1 /* Target hook definitions.
2 Copyright (C) 2001-2021 Free Software Foundation, Inc.
4 This program is free software; you can redistribute it and/or modify it
5 under the terms of the GNU General Public License as published by the
6 Free Software Foundation; either version 3, or (at your option) any
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; see the file COPYING3. If not see
16 <http://www.gnu.org/licenses/>.
18 In other words, you are welcome to use, share and improve this program.
19 You are forbidden to forbid anyone else to use, share and improve
20 what you give them. Help stamp out software-hoarding! */
22 /* See target-hooks-macros.h for details of macros that should be
23 provided by the including file, and how to use them here. */
24 #include "target-hooks-macros.h"
27 #define HOOK_TYPE "Target Hook"
29 HOOK_VECTOR (TARGET_INITIALIZER, gcc_target)
31 /* Functions that output assembler for the target. */
32 #define HOOK_PREFIX "TARGET_ASM_"
33 HOOK_VECTOR (TARGET_ASM_OUT, asm_out)
35 /* Opening and closing parentheses for asm expression grouping. */
38 "These target hooks are C string constants, describing the syntax in the\n\
39 assembler for grouping arithmetic expressions. If not overridden, they\n\
40 default to normal parentheses, which is correct for most assemblers.",
42 DEFHOOKPODX (close_paren, const char *, ")")
44 /* Assembler instructions for creating various kinds of integer object. */
47 "@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_HI_OP\n\
48 @deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_PSI_OP\n\
49 @deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_SI_OP\n\
50 @deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_PDI_OP\n\
51 @deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_DI_OP\n\
52 @deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_PTI_OP\n\
53 @deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_TI_OP\n\
54 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_HI_OP\n\
55 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_PSI_OP\n\
56 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_SI_OP\n\
57 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_PDI_OP\n\
58 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_DI_OP\n\
59 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_PTI_OP\n\
60 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_TI_OP\n\
61 These hooks specify assembly directives for creating certain kinds\n\
62 of integer object. The @code{TARGET_ASM_BYTE_OP} directive creates a\n\
63 byte-sized object, the @code{TARGET_ASM_ALIGNED_HI_OP} one creates an\n\
64 aligned two-byte object, and so on. Any of the hooks may be\n\
65 @code{NULL}, indicating that no suitable directive is available.\n\
67 The compiler will print these strings at the start of a new line,\n\
68 followed immediately by the object's initial value. In most cases,\n\
69 the string should contain a tab, a pseudo-op, and then another tab.",
70 const char *, "\t.byte\t")
71 DEFHOOKPOD (aligned_op, "*", struct asm_int_op, TARGET_ASM_ALIGNED_INT_OP)
72 DEFHOOKPOD (unaligned_op, "*", struct asm_int_op, TARGET_ASM_UNALIGNED_INT_OP)
74 /* Try to output the assembler code for an integer object whose
75 value is given by X. SIZE is the size of the object in bytes and
76 ALIGNED_P indicates whether it is aligned. Return true if
77 successful. Only handles cases for which BYTE_OP, ALIGNED_OP
78 and UNALIGNED_OP are NULL. */
81 "The @code{assemble_integer} function uses this hook to output an\n\
82 integer object. @var{x} is the object's value, @var{size} is its size\n\
83 in bytes and @var{aligned_p} indicates whether it is aligned. The\n\
84 function should return @code{true} if it was able to output the\n\
85 object. If it returns false, @code{assemble_integer} will try to\n\
86 split the object into smaller parts.\n\
88 The default implementation of this hook will use the\n\
89 @code{TARGET_ASM_BYTE_OP} family of strings, returning @code{false}\n\
90 when the relevant string is @code{NULL}.",
91 /* Only handles cases for which BYTE_OP, ALIGNED_OP and UNALIGNED_OP are
93 bool, (rtx x, unsigned int size, int aligned_p),
94 default_assemble_integer)
96 /* Assembly strings required after the .cfi_startproc label. */
99 "This target hook is used to emit assembly strings required by the target\n\
100 after the .cfi_startproc directive. The first argument is the file stream to\n\
101 write the strings to and the second argument is the function\'s declaration. The\n\
102 expected use is to add more .cfi_* directives.\n\
104 The default is to not output any assembly strings.",
105 void, (FILE *, tree),
106 hook_void_FILEptr_tree)
108 /* Notify the backend that we have completed emitting the data for a
112 "Define this hook if the target assembler requires a special marker to\n\
113 terminate an initialized variable declaration.",
117 /* Output code that will globalize a label. */
120 "This target hook is a function to output to the stdio stream\n\
121 @var{stream} some commands that will make the label @var{name} global;\n\
122 that is, available for reference from other files.\n\
124 The default implementation relies on a proper definition of\n\
125 @code{GLOBAL_ASM_OP}.",
126 void, (FILE *stream, const char *name),
127 default_globalize_label)
129 /* Output code that will globalize a declaration. */
131 (globalize_decl_name,
132 "This target hook is a function to output to the stdio stream\n\
133 @var{stream} some commands that will make the name associated with @var{decl}\n\
134 global; that is, available for reference from other files.\n\
136 The default implementation uses the TARGET_ASM_GLOBALIZE_LABEL target hook.",
137 void, (FILE *stream, tree decl), default_globalize_decl_name)
139 /* Output code that will declare an external variable. */
141 (assemble_undefined_decl,
142 "This target hook is a function to output to the stdio stream\n\
143 @var{stream} some commands that will declare the name associated with\n\
144 @var{decl} which is not defined in the current translation unit. Most\n\
145 assemblers do not require anything to be output in this case.",
146 void, (FILE *stream, const char *name, const_tree decl),
147 hook_void_FILEptr_constcharptr_const_tree)
149 /* Output code that will emit a label for unwind info, if this
150 target requires such labels. Second argument is the decl the
151 unwind info is associated with, third is a boolean: true if
152 this is for exception handling, fourth is a boolean: true if
153 this is only a placeholder for an omitted FDE. */
156 "This target hook emits a label at the beginning of each FDE@. It\n\
157 should be defined on targets where FDEs need special labels, and it\n\
158 should write the appropriate label, for the FDE associated with the\n\
159 function declaration @var{decl}, to the stdio stream @var{stream}.\n\
160 The third argument, @var{for_eh}, is a boolean: true if this is for an\n\
161 exception table. The fourth argument, @var{empty}, is a boolean:\n\
162 true if this is a placeholder label for an omitted FDE@.\n\
164 The default is that FDEs are not given nonlocal labels.",
165 void, (FILE *stream, tree decl, int for_eh, int empty),
166 default_emit_unwind_label)
168 /* Output code that will emit a label to divide up the exception table. */
170 (emit_except_table_label,
171 "This target hook emits a label at the beginning of the exception table.\n\
172 It should be defined on targets where it is desirable for the table\n\
173 to be broken up according to function.\n\
175 The default is that no label is emitted.",
176 void, (FILE *stream),
177 default_emit_except_table_label)
179 /* Emit a directive for setting the personality for the function. */
181 (emit_except_personality,
182 "If the target implements @code{TARGET_ASM_UNWIND_EMIT}, this hook may be\
183 used to emit a directive to install a personality hook into the unwind\
184 info. This hook should not be used if dwarf2 unwind info is used.",
185 void, (rtx personality),
188 /* If necessary, modify personality and LSDA references to handle
189 indirection. This is used when the assembler supports CFI directives. */
191 (make_eh_symbol_indirect,
192 "If necessary, modify personality and LSDA references to handle indirection.\
193 The original symbol is in @code{origsymbol} and if @code{pubvis} is true\
194 the symbol is visible outside the TU.",
195 rtx, (rtx origsymbol, bool pubvis),
198 /* Emit any directives required to unwind this instruction. */
201 "This target hook emits assembly directives required to unwind the\n\
202 given instruction. This is only used when @code{TARGET_EXCEPT_UNWIND_INFO}\n\
203 returns @code{UI_TARGET}.",
204 void, (FILE *stream, rtx_insn *insn),
208 (unwind_emit_before_insn,
209 "True if the @code{TARGET_ASM_UNWIND_EMIT} hook should be called before\
210 the assembly for @var{insn} has been emitted, false if the hook should\
211 be called afterward.",
214 /* Return true if the target needs extra instructions to restore the current
215 frame address after a DW_CFA_restore_state opcode. */
217 (should_restore_cfa_state,
218 "For DWARF-based unwind frames, two CFI instructions provide for save and\
219 restore of register state. GCC maintains the current frame address (CFA)\
220 separately from the register bank but the unwinder in libgcc preserves this\
221 state along with the registers (and this is expected by the code that writes\
222 the unwind frames). This hook allows the target to specify that the CFA data\
223 is not saved/restored along with the registers by the target unwinder so that\
224 suitable additional instructions should be emitted to restore it.",
226 hook_bool_void_false)
228 /* Generate an internal label.
229 For now this is just a wrapper for ASM_GENERATE_INTERNAL_LABEL. */
231 (generate_internal_label,
233 void, (char *buf, const char *prefix, unsigned long labelno),
234 default_generate_internal_label)
236 /* Output an internal label. */
239 "A function to output to the stdio stream @var{stream} a label whose\n\
240 name is made from the string @var{prefix} and the number @var{labelno}.\n\
242 It is absolutely essential that these labels be distinct from the labels\n\
243 used for user-level functions and variables. Otherwise, certain programs\n\
244 will have name conflicts with internal labels.\n\
246 It is desirable to exclude internal labels from the symbol table of the\n\
247 object file. Most assemblers have a naming convention for labels that\n\
248 should be excluded; on many systems, the letter @samp{L} at the\n\
249 beginning of a label has this effect. You should find out what\n\
250 convention your system uses, and follow it.\n\
252 The default version of this function utilizes @code{ASM_GENERATE_INTERNAL_LABEL}.",
253 void, (FILE *stream, const char *prefix, unsigned long labelno),
254 default_internal_label)
256 /* Output label for the constant. */
258 (declare_constant_name,
259 "A target hook to output to the stdio stream @var{file} any text necessary\n\
260 for declaring the name @var{name} of a constant which is being defined. This\n\
261 target hook is responsible for outputting the label definition (perhaps using\n\
262 @code{assemble_label}). The argument @var{exp} is the value of the constant,\n\
263 and @var{size} is the size of the constant in bytes. The @var{name}\n\
264 will be an internal label.\n\
266 The default version of this target hook, define the @var{name} in the\n\
267 usual manner as a label (by means of @code{assemble_label}).\n\
269 You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} in this target hook.",
270 void, (FILE *file, const char *name, const_tree expr, HOST_WIDE_INT size),
271 default_asm_declare_constant_name)
273 /* Emit a ttype table reference to a typeinfo object. */
276 "This hook is used to output a reference from a frame unwinding table to\n\
277 the type_info object identified by @var{sym}. It should return @code{true}\n\
278 if the reference was output. Returning @code{false} will cause the\n\
279 reference to be output using the normal Dwarf2 routines.",
283 /* Emit an assembler directive to set visibility for the symbol
284 associated with the tree decl. */
286 (assemble_visibility,
287 "This target hook is a function to output to @var{asm_out_file} some\n\
288 commands that will make the symbol(s) associated with @var{decl} have\n\
289 hidden, protected or internal visibility as specified by @var{visibility}.",
290 void, (tree decl, int visibility),
291 default_assemble_visibility)
294 (print_patchable_function_entry,
295 "Generate a patchable area at the function start, consisting of\n\
296 @var{patch_area_size} NOP instructions. If the target supports named\n\
297 sections and if @var{record_p} is true, insert a pointer to the current\n\
298 location in the table of patchable functions. The default implementation\n\
299 of the hook places the table of pointers in the special section named\n\
300 @code{__patchable_function_entries}.",
301 void, (FILE *file, unsigned HOST_WIDE_INT patch_area_size, bool record_p),
302 default_print_patchable_function_entry)
304 /* Output the assembler code for entry to a function. */
307 "If defined, a function that outputs the assembler code for entry to a\n\
308 function. The prologue is responsible for setting up the stack frame,\n\
309 initializing the frame pointer register, saving registers that must be\n\
310 saved, and allocating @var{size} additional bytes of storage for the\n\
311 local variables. @var{file} is a stdio stream to which the assembler\n\
312 code should be output.\n\
314 The label for the beginning of the function need not be output by this\n\
315 macro. That has already been done when the macro is run.\n\
317 @findex regs_ever_live\n\
318 To determine which registers to save, the macro can refer to the array\n\
319 @code{regs_ever_live}: element @var{r} is nonzero if hard register\n\
320 @var{r} is used anywhere within the function. This implies the function\n\
321 prologue should save register @var{r}, provided it is not one of the\n\
322 call-used registers. (@code{TARGET_ASM_FUNCTION_EPILOGUE} must likewise use\n\
323 @code{regs_ever_live}.)\n\
325 On machines that have ``register windows'', the function entry code does\n\
326 not save on the stack the registers that are in the windows, even if\n\
327 they are supposed to be preserved by function calls; instead it takes\n\
328 appropriate steps to ``push'' the register stack, if any non-call-used\n\
329 registers are used in the function.\n\
331 @findex frame_pointer_needed\n\
332 On machines where functions may or may not have frame-pointers, the\n\
333 function entry code must vary accordingly; it must set up the frame\n\
334 pointer if one is wanted, and not otherwise. To determine whether a\n\
335 frame pointer is in wanted, the macro can refer to the variable\n\
336 @code{frame_pointer_needed}. The variable's value will be 1 at run\n\
337 time in a function that needs a frame pointer. @xref{Elimination}.\n\
339 The function entry code is responsible for allocating any stack space\n\
340 required for the function. This stack space consists of the regions\n\
341 listed below. In most cases, these regions are allocated in the\n\
342 order listed, with the last listed region closest to the top of the\n\
343 stack (the lowest address if @code{STACK_GROWS_DOWNWARD} is defined, and\n\
344 the highest address if it is not defined). You can use a different order\n\
345 for a machine if doing so is more convenient or required for\n\
346 compatibility reasons. Except in cases where required by standard\n\
347 or by a debugger, there is no reason why the stack layout used by GCC\n\
348 need agree with that used by other compilers for a machine.",
350 default_function_pro_epilogue)
352 /* Output the assembler code for end of prologue. */
354 (function_end_prologue,
355 "If defined, a function that outputs assembler code at the end of a\n\
356 prologue. This should be used when the function prologue is being\n\
357 emitted as RTL, and you have some extra assembler that needs to be\n\
358 emitted. @xref{prologue instruction pattern}.",
362 /* Output the assembler code for start of epilogue. */
364 (function_begin_epilogue,
365 "If defined, a function that outputs assembler code at the start of an\n\
366 epilogue. This should be used when the function epilogue is being\n\
367 emitted as RTL, and you have some extra assembler that needs to be\n\
368 emitted. @xref{epilogue instruction pattern}.",
372 /* Output the assembler code for function exit. */
375 "If defined, a function that outputs the assembler code for exit from a\n\
376 function. The epilogue is responsible for restoring the saved\n\
377 registers and stack pointer to their values when the function was\n\
378 called, and returning control to the caller. This macro takes the\n\
379 same argument as the macro @code{TARGET_ASM_FUNCTION_PROLOGUE}, and the\n\
380 registers to restore are determined from @code{regs_ever_live} and\n\
381 @code{CALL_USED_REGISTERS} in the same way.\n\
383 On some machines, there is a single instruction that does all the work\n\
384 of returning from the function. On these machines, give that\n\
385 instruction the name @samp{return} and do not define the macro\n\
386 @code{TARGET_ASM_FUNCTION_EPILOGUE} at all.\n\
388 Do not define a pattern named @samp{return} if you want the\n\
389 @code{TARGET_ASM_FUNCTION_EPILOGUE} to be used. If you want the target\n\
390 switches to control whether return instructions or epilogues are used,\n\
391 define a @samp{return} pattern with a validity condition that tests the\n\
392 target switches appropriately. If the @samp{return} pattern's validity\n\
393 condition is false, epilogues will be used.\n\
395 On machines where functions may or may not have frame-pointers, the\n\
396 function exit code must vary accordingly. Sometimes the code for these\n\
397 two cases is completely different. To determine whether a frame pointer\n\
398 is wanted, the macro can refer to the variable\n\
399 @code{frame_pointer_needed}. The variable's value will be 1 when compiling\n\
400 a function that needs a frame pointer.\n\
402 Normally, @code{TARGET_ASM_FUNCTION_PROLOGUE} and\n\
403 @code{TARGET_ASM_FUNCTION_EPILOGUE} must treat leaf functions specially.\n\
404 The C variable @code{current_function_is_leaf} is nonzero for such a\n\
405 function. @xref{Leaf Functions}.\n\
407 On some machines, some functions pop their arguments on exit while\n\
408 others leave that for the caller to do. For example, the 68020 when\n\
409 given @option{-mrtd} pops arguments in functions that take a fixed\n\
410 number of arguments.\n\
413 @findex crtl->args.pops_args\n\
414 Your definition of the macro @code{RETURN_POPS_ARGS} decides which\n\
415 functions pop their own arguments. @code{TARGET_ASM_FUNCTION_EPILOGUE}\n\
416 needs to know what was decided. The number of bytes of the current\n\
417 function's arguments that this function should pop is available in\n\
418 @code{crtl->args.pops_args}. @xref{Scalar Return}.",
420 default_function_pro_epilogue)
422 /* Initialize target-specific sections. */
425 "Define this hook if you need to do something special to set up the\n\
426 @file{varasm.c} sections, or if your target has some special sections\n\
427 of its own that you need to create.\n\
429 GCC calls this hook after processing the command line, but before writing\n\
430 any assembly code, and before calling any of the section-returning hooks\n\
435 /* Tell assembler to change to section NAME with attributes FLAGS.
436 If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with
437 which this section is associated. */
440 "Output assembly directives to switch to section @var{name}. The section\n\
441 should have attributes as specified by @var{flags}, which is a bit mask\n\
442 of the @code{SECTION_*} flags defined in @file{output.h}. If @var{decl}\n\
443 is non-NULL, it is the @code{VAR_DECL} or @code{FUNCTION_DECL} with which\n\
444 this section is associated.",
445 void, (const char *name, unsigned int flags, tree decl),
446 default_no_named_section)
448 /* Tell assembler what section attributes to assign this elf section
449 declaration, using their numerical value. */
452 "This hook can be used to encode ELF section flags for which no letter\n\
453 code has been defined in the assembler. It is called by\n\
454 @code{default_asm_named_section} whenever the section flags need to be\n\
455 emitted in the assembler output. If the hook returns true, then the\n\
456 numerical value for ELF section flags should be calculated from\n\
457 @var{flags} and saved in @var{*num}; the value is printed out instead of the\n\
458 normal sequence of letter codes. If the hook is not defined, or if it\n\
459 returns false, then @var{num} is ignored and the traditional letter sequence\n\
461 bool, (unsigned int flags, unsigned int *num),
462 hook_bool_uint_uintp_false)
464 /* Return preferred text (sub)section for function DECL.
465 Main purpose of this function is to separate cold, normal and hot
466 functions. STARTUP is true when function is known to be used only
467 at startup (from static constructors or it is main()).
468 EXIT is true when function is known to be used only at exit
469 (from static destructors).
470 Return NULL if function should go to default text section. */
473 "Return preferred text (sub)section for function @var{decl}.\n\
474 Main purpose of this function is to separate cold, normal and hot\n\
475 functions. @var{startup} is true when function is known to be used only\n\
476 at startup (from static constructors or it is @code{main()}).\n\
477 @var{exit} is true when function is known to be used only at exit\n\
478 (from static destructors).\n\
479 Return NULL if function should go to default text section.",
480 section *, (tree decl, enum node_frequency freq, bool startup, bool exit),
481 default_function_section)
483 /* Output the assembler code for function exit. */
485 (function_switched_text_sections,
486 "Used by the target to emit any assembler directives or additional\
487 labels needed when a function is partitioned between different\
488 sections. Output should be written to @var{file}. The function\
489 decl is available as @var{decl} and the new section is `cold' if\
490 @var{new_is_cold} is @code{true}.",
491 void, (FILE *file, tree decl, bool new_is_cold),
492 default_function_switched_text_sections)
494 /* Return a mask describing how relocations should be treated when
495 selecting sections. Bit 1 should be set if global relocations
496 should be placed in a read-write section; bit 0 should be set if
497 local relocations should be placed in a read-write section. */
500 "Return a mask describing how relocations should be treated when\n\
501 selecting sections. Bit 1 should be set if global relocations\n\
502 should be placed in a read-write section; bit 0 should be set if\n\
503 local relocations should be placed in a read-write section.\n\
505 The default version of this function returns 3 when @option{-fpic}\n\
506 is in effect, and 0 otherwise. The hook is typically redefined\n\
507 when the target cannot support (some kinds of) dynamic relocations\n\
508 in read-only sections even in executables.",
510 default_reloc_rw_mask)
512 /* Return a flag for either generating ADDR_DIF_VEC table
513 or ADDR_VEC table for jumps in case of -fPIC/-fPIE. */
515 (generate_pic_addr_diff_vec,
516 "Return true to generate ADDR_DIF_VEC table\n\
517 or false to generate ADDR_VEC table for jumps in case of -fPIC.\n\
519 The default version of this function returns true if flag_pic\n\
520 equals true and false otherwise",
522 default_generate_pic_addr_diff_vec)
524 /* Return a section for EXP. It may be a DECL or a constant. RELOC
525 is nonzero if runtime relocations must be applied; bit 1 will be
526 set if the runtime relocations require non-local name resolution.
527 ALIGN is the required alignment of the data. */
530 "Return the section into which @var{exp} should be placed. You can\n\
531 assume that @var{exp} is either a @code{VAR_DECL} node or a constant of\n\
532 some sort. @var{reloc} indicates whether the initial value of @var{exp}\n\
533 requires link-time relocations. Bit 0 is set when variable contains\n\
534 local relocations only, while bit 1 is set for global relocations.\n\
535 @var{align} is the constant alignment in bits.\n\
537 The default version of this function takes care of putting read-only\n\
538 variables in @code{readonly_data_section}.\n\
540 See also @var{USE_SELECT_SECTION_FOR_FUNCTIONS}.",
541 section *, (tree exp, int reloc, unsigned HOST_WIDE_INT align),
542 default_select_section)
544 /* Return a section for X. MODE is X's mode and ALIGN is its
545 alignment in bits. */
548 "Return the section into which a constant @var{x}, of mode @var{mode},\n\
549 should be placed. You can assume that @var{x} is some kind of\n\
550 constant in RTL@. The argument @var{mode} is redundant except in the\n\
551 case of a @code{const_int} rtx. @var{align} is the constant alignment\n\
554 The default version of this function takes care of putting symbolic\n\
555 constants in @code{flag_pic} mode in @code{data_section} and everything\n\
556 else in @code{readonly_data_section}.",
557 section *, (machine_mode mode, rtx x, unsigned HOST_WIDE_INT align),
558 default_select_rtx_section)
560 /* Select a unique section name for DECL. RELOC is the same as
561 for SELECT_SECTION. */
564 "Build up a unique section name, expressed as a @code{STRING_CST} node,\n\
565 and assign it to @samp{DECL_SECTION_NAME (@var{decl})}.\n\
566 As with @code{TARGET_ASM_SELECT_SECTION}, @var{reloc} indicates whether\n\
567 the initial value of @var{exp} requires link-time relocations.\n\
569 The default version of this function appends the symbol name to the\n\
570 ELF section name that would normally be used for the symbol. For\n\
571 example, the function @code{foo} would be placed in @code{.text.foo}.\n\
572 Whatever the actual target object format, this is often good enough.",
573 void, (tree decl, int reloc),
574 default_unique_section)
576 /* Return the readonly data or relocated readonly data section
577 associated with function DECL. */
579 (function_rodata_section,
580 "Return the readonly data or reloc readonly data section associated with\n\
581 @samp{DECL_SECTION_NAME (@var{decl})}. @var{relocatable} selects the latter\n\
583 The default version of this function selects @code{.gnu.linkonce.r.name} if\n\
584 the function's section is @code{.gnu.linkonce.t.name}, @code{.rodata.name}\n\
585 or @code{.data.rel.ro.name} if function is in @code{.text.name}, and\n\
586 the normal readonly-data or reloc readonly data section otherwise.",
587 section *, (tree decl, bool relocatable),
588 default_function_rodata_section)
590 /* Nonnull if the target wants to override the default ".rodata" prefix
591 for mergeable data sections. */
593 (mergeable_rodata_prefix,
594 "Usually, the compiler uses the prefix @code{\".rodata\"} to construct\n\
595 section names for mergeable constant data. Define this macro to override\n\
596 the string if a different section name should be used.",
597 const char *, ".rodata")
599 /* Return the section to be used for transactional memory clone tables. */
601 (tm_clone_table_section,
602 "Return the section that should be used for transactional memory clone\
604 section *, (void), default_clone_table_section)
606 /* Output a constructor for a symbol with a given priority. */
609 "If defined, a function that outputs assembler code to arrange to call\n\
610 the function referenced by @var{symbol} at initialization time.\n\
612 Assume that @var{symbol} is a @code{SYMBOL_REF} for a function taking\n\
613 no arguments and with no return value. If the target supports initialization\n\
614 priorities, @var{priority} is a value between 0 and @code{MAX_INIT_PRIORITY};\n\
615 otherwise it must be @code{DEFAULT_INIT_PRIORITY}.\n\
617 If this macro is not defined by the target, a suitable default will\n\
618 be chosen if (1) the target supports arbitrary section names, (2) the\n\
619 target defines @code{CTORS_SECTION_ASM_OP}, or (3) @code{USE_COLLECT2}\n\
621 void, (rtx symbol, int priority), NULL)
623 /* Output a destructor for a symbol with a given priority. */
626 "This is like @code{TARGET_ASM_CONSTRUCTOR} but used for termination\n\
627 functions rather than initialization functions.",
628 void, (rtx symbol, int priority), NULL)
630 /* Output the assembler code for a thunk function. THUNK_DECL is the
631 declaration for the thunk function itself, FUNCTION is the decl for
632 the target function. DELTA is an immediate constant offset to be
633 added to THIS. If VCALL_OFFSET is nonzero, the word at
634 *(*this + vcall_offset) should be added to THIS. */
637 "A function that outputs the assembler code for a thunk\n\
638 function, used to implement C++ virtual function calls with multiple\n\
639 inheritance. The thunk acts as a wrapper around a virtual function,\n\
640 adjusting the implicit object parameter before handing control off to\n\
641 the real function.\n\
643 First, emit code to add the integer @var{delta} to the location that\n\
644 contains the incoming first argument. Assume that this argument\n\
645 contains a pointer, and is the one used to pass the @code{this} pointer\n\
646 in C++. This is the incoming argument @emph{before} the function prologue,\n\
647 e.g.@: @samp{%o0} on a sparc. The addition must preserve the values of\n\
648 all other incoming arguments.\n\
650 Then, if @var{vcall_offset} is nonzero, an additional adjustment should be\n\
651 made after adding @code{delta}. In particular, if @var{p} is the\n\
652 adjusted pointer, the following adjustment should be made:\n\
655 p += (*((ptrdiff_t **)p))[vcall_offset/sizeof(ptrdiff_t)]\n\
658 After the additions, emit code to jump to @var{function}, which is a\n\
659 @code{FUNCTION_DECL}. This is a direct pure jump, not a call, and does\n\
660 not touch the return address. Hence returning from @var{FUNCTION} will\n\
661 return to whoever called the current @samp{thunk}.\n\
663 The effect must be as if @var{function} had been called directly with\n\
664 the adjusted first argument. This macro is responsible for emitting all\n\
665 of the code for a thunk function; @code{TARGET_ASM_FUNCTION_PROLOGUE}\n\
666 and @code{TARGET_ASM_FUNCTION_EPILOGUE} are not invoked.\n\
668 The @var{thunk_fndecl} is redundant. (@var{delta} and @var{function}\n\
669 have already been extracted from it.) It might possibly be useful on\n\
670 some targets, but probably not.\n\
672 If you do not define this macro, the target-independent code in the C++\n\
673 front end will generate a less efficient heavyweight thunk that calls\n\
674 @var{function} instead of jumping to it. The generic approach does\n\
675 not support varargs.",
676 void, (FILE *file, tree thunk_fndecl, HOST_WIDE_INT delta,
677 HOST_WIDE_INT vcall_offset, tree function),
680 /* Determine whether output_mi_thunk would succeed. */
681 /* ??? Ideally, this hook would not exist, and success or failure
682 would be returned from output_mi_thunk directly. But there's
683 too much undo-able setup involved in invoking output_mi_thunk.
684 Could be fixed by making output_mi_thunk emit rtl instead of
685 text to the output file. */
687 (can_output_mi_thunk,
688 "A function that returns true if TARGET_ASM_OUTPUT_MI_THUNK would be able\n\
689 to output the assembler code for the thunk function specified by the\n\
690 arguments it is passed, and false otherwise. In the latter case, the\n\
691 generic approach will be used by the C++ front end, with the limitations\n\
692 previously exposed.",
693 bool, (const_tree thunk_fndecl, HOST_WIDE_INT delta,
694 HOST_WIDE_INT vcall_offset, const_tree function),
695 hook_bool_const_tree_hwi_hwi_const_tree_false)
697 /* Output any boilerplate text needed at the beginning of a
701 "Output to @code{asm_out_file} any text which the assembler expects to\n\
702 find at the beginning of a file. The default behavior is controlled\n\
703 by two flags, documented below. Unless your target's assembler is\n\
704 quite unusual, if you override the default, you should call\n\
705 @code{default_file_start} at some point in your target hook. This\n\
706 lets other target files rely on these variables.",
710 /* Output any boilerplate text needed at the end of a translation unit. */
713 "Output to @code{asm_out_file} any text which the assembler expects\n\
714 to find at the end of a file. The default is to output nothing.",
718 /* Output any boilerplate text needed at the beginning of an
719 LTO output stream. */
722 "Output to @code{asm_out_file} any text which the assembler expects\n\
723 to find at the start of an LTO section. The default is to output\n\
728 /* Output any boilerplate text needed at the end of an
729 LTO output stream. */
732 "Output to @code{asm_out_file} any text which the assembler expects\n\
733 to find at the end of an LTO section. The default is to output\n\
738 /* Output any boilerplace text needed at the end of a
739 translation unit before debug and unwind info is emitted. */
742 "Output to @code{asm_out_file} any text which is needed before emitting\n\
743 unwind info and debug info at the end of a file. Some targets emit\n\
744 here PIC setup thunks that cannot be emitted at the end of file,\n\
745 because they couldn't have unwind info then. The default is to output\n\
750 /* Output an assembler pseudo-op to declare a library function name
754 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
755 pseudo-op to declare a library function name external. The name of the\n\
756 library function is given by @var{symref}, which is a @code{symbol_ref}.",
758 default_external_libcall)
760 /* Output an assembler directive to mark decl live. This instructs
761 linker to not dead code strip this symbol. */
763 (mark_decl_preserved,
764 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
765 directive to annotate @var{symbol} as used. The Darwin target uses the\n\
766 .no_dead_code_strip directive.",
767 void, (const char *symbol),
768 hook_void_constcharptr)
770 /* Output a record of the command line switches that have been passed. */
772 (record_gcc_switches,
773 "Provides the target with the ability to record the gcc command line\n\
774 switches provided as argument.\n\
776 By default this hook is set to NULL, but an example implementation is\n\
777 provided for ELF based targets. Called @var{elf_record_gcc_switches},\n\
778 it records the switches as ASCII text inside a new, string mergeable\n\
779 section in the assembler output file. The name of the new section is\n\
780 provided by the @code{TARGET_ASM_RECORD_GCC_SWITCHES_SECTION} target\n\
782 void, (const char *),
785 /* The name of the section that the example ELF implementation of
786 record_gcc_switches will use to store the information. Target
787 specific versions of record_gcc_switches may or may not use
790 (record_gcc_switches_section,
791 "This is the name of the section that will be created by the example\n\
792 ELF implementation of the @code{TARGET_ASM_RECORD_GCC_SWITCHES} target\n\
794 const char *, ".GCC.command.line")
796 /* Output the definition of a section anchor. */
799 "Write the assembly code to define section anchor @var{x}, which is a\n\
800 @code{SYMBOL_REF} for which @samp{SYMBOL_REF_ANCHOR_P (@var{x})} is true.\n\
801 The hook is called with the assembly output position set to the beginning\n\
802 of @code{SYMBOL_REF_BLOCK (@var{x})}.\n\
804 If @code{ASM_OUTPUT_DEF} is available, the hook's default definition uses\n\
805 it to define the symbol as @samp{. + SYMBOL_REF_BLOCK_OFFSET (@var{x})}.\n\
806 If @code{ASM_OUTPUT_DEF} is not available, the hook's default definition\n\
807 is @code{NULL}, which disables the use of section anchors altogether.",
809 default_asm_output_anchor)
813 "Output a string based on @var{name}, suitable for the @samp{#ident} \
814 directive, or the equivalent directive or pragma in non-C-family languages. \
815 If this hook is not defined, nothing is output for the @samp{#ident} \
817 void, (const char *name),
818 hook_void_constcharptr)
820 /* Output a DTP-relative reference to a TLS symbol. */
822 (output_dwarf_dtprel,
823 "If defined, this target hook is a function which outputs a DTP-relative\n\
824 reference to the given TLS symbol of the specified size.",
825 void, (FILE *file, int size, rtx x),
828 /* Some target machines need to postscan each insn after it is output. */
830 (final_postscan_insn,
831 "If defined, this target hook is a function which is executed just after the\n\
832 output of assembler code for @var{insn}, to change the mode of the assembler\n\
835 Here the argument @var{opvec} is the vector containing the operands\n\
836 extracted from @var{insn}, and @var{noperands} is the number of\n\
837 elements of the vector which contain meaningful data for this insn.\n\
838 The contents of this vector are what was used to convert the insn\n\
839 template into assembler code, so you can change the assembler mode\n\
840 by checking the contents of the vector.",
841 void, (FILE *file, rtx_insn *insn, rtx *opvec, int noperands),
844 /* Emit the trampoline template. This hook may be NULL. */
846 (trampoline_template,
847 "This hook is called by @code{assemble_trampoline_template} to output,\n\
848 on the stream @var{f}, assembler code for a block of data that contains\n\
849 the constant parts of a trampoline. This code should not include a\n\
850 label---the label is taken care of automatically.\n\
852 If you do not define this hook, it means no template is needed\n\
853 for the target. Do not define this hook on systems where the block move\n\
854 code to copy the trampoline into place would be larger than the code\n\
855 to generate it on the spot.",
860 (output_source_filename,
861 "Output DWARF debugging information which indicates that filename\
862 @var{name} is the current source file to the stdio stream @var{file}.\n\
864 This target hook need not be defined if the standard form of output\
865 for the file format in use is appropriate.",
866 void ,(FILE *file, const char *name),
867 default_asm_output_source_filename)
870 (output_addr_const_extra,
871 "A target hook to recognize @var{rtx} patterns that @code{output_addr_const}\n\
872 can't deal with, and output assembly code to @var{file} corresponding to\n\
873 the pattern @var{x}. This may be used to allow machine-dependent\n\
874 @code{UNSPEC}s to appear within constants.\n\
876 If target hook fails to recognize a pattern, it must return @code{false},\n\
877 so that a standard error message is printed. If it prints an error message\n\
878 itself, by calling, for example, @code{output_operand_lossage}, it may just\n\
879 return @code{true}.",
880 bool, (FILE *file, rtx x),
881 hook_bool_FILEptr_rtx_false)
883 /* ??? The TARGET_PRINT_OPERAND* hooks are part of the asm_out struct,
884 even though that is not reflected in the macro name to override their
887 #define HOOK_PREFIX "TARGET_"
889 /* Emit a machine-specific insn operand. */
890 /* ??? tm.texi only documents the old macro PRINT_OPERAND,
891 not this hook, and uses a different name for the argument FILE. */
895 void, (FILE *file, rtx x, int code),
896 default_print_operand)
898 /* Emit a machine-specific memory address. */
899 /* ??? tm.texi only documents the old macro PRINT_OPERAND_ADDRESS,
900 not this hook, and uses different argument names. */
902 (print_operand_address,
904 void, (FILE *file, machine_mode mode, rtx addr),
905 default_print_operand_address)
907 /* Determine whether CODE is a valid punctuation character for the
908 `print_operand' hook. */
909 /* ??? tm.texi only documents the old macro PRINT_OPERAND_PUNCT_VALID_P,
912 (print_operand_punct_valid_p,
914 bool ,(unsigned char code),
915 default_print_operand_punct_valid_p)
917 /* Given a symbol name, perform same mangling as assemble_name and
918 ASM_OUTPUT_LABELREF, returning result as an IDENTIFIER_NODE. */
920 (mangle_assembler_name,
921 "Given a symbol @var{name}, perform same mangling as @code{varasm.c}'s\
922 @code{assemble_name}, but in memory rather than to a file stream, returning\
923 result as an @code{IDENTIFIER_NODE}. Required for correct LTO symtabs. The\
924 default implementation calls the @code{TARGET_STRIP_NAME_ENCODING} hook and\
925 then prepends the @code{USER_LABEL_PREFIX}, if any.",
926 tree, (const char *name),
927 default_mangle_assembler_name)
929 HOOK_VECTOR_END (asm_out)
931 /* Functions relating to instruction scheduling. All of these
932 default to null pointers, which haifa-sched.c looks for and handles. */
934 #define HOOK_PREFIX "TARGET_SCHED_"
935 HOOK_VECTOR (TARGET_SCHED, sched)
937 /* Given the current cost, COST, of an insn, INSN, calculate and
938 return a new cost based on its relationship to DEP_INSN through
939 the dependence LINK. The default is to make no adjustment. */
942 "This function corrects the value of @var{cost} based on the\n\
943 relationship between @var{insn} and @var{dep_insn} through a\n\
944 dependence of type dep_type, and strength @var{dw}. It should return the new\n\
945 value. The default is to make no adjustment to @var{cost}. This can be\n\
946 used for example to specify to the scheduler using the traditional pipeline\n\
947 description that an output- or anti-dependence does not incur the same cost\n\
948 as a data-dependence. If the scheduler using the automaton based pipeline\n\
949 description, the cost of anti-dependence is zero and the cost of\n\
950 output-dependence is maximum of one and the difference of latency\n\
951 times of the first and the second insns. If these values are not\n\
952 acceptable, you could use the hook to modify them too. See also\n\
953 @pxref{Processor pipeline description}.",
954 int, (rtx_insn *insn, int dep_type1, rtx_insn *dep_insn, int cost,
958 /* Adjust the priority of an insn as you see fit. Returns the new priority. */
961 "This hook adjusts the integer scheduling priority @var{priority} of\n\
962 @var{insn}. It should return the new priority. Increase the priority to\n\
963 execute @var{insn} earlier, reduce the priority to execute @var{insn}\n\
964 later. Do not define this hook if you do not need to adjust the\n\
965 scheduling priorities of insns.",
966 int, (rtx_insn *insn, int priority), NULL)
968 /* Function which returns the maximum number of insns that can be
969 scheduled in the same machine cycle. This must be constant
970 over an entire compilation. The default is 1. */
973 "This hook returns the maximum number of instructions that can ever\n\
974 issue at the same time on the target machine. The default is one.\n\
975 Although the insn scheduler can define itself the possibility of issue\n\
976 an insn on the same cycle, the value can serve as an additional\n\
977 constraint to issue insns on the same simulated processor cycle (see\n\
978 hooks @samp{TARGET_SCHED_REORDER} and @samp{TARGET_SCHED_REORDER2}).\n\
979 This value must be constant over the entire compilation. If you need\n\
980 it to vary depending on what the instructions are, you must use\n\
981 @samp{TARGET_SCHED_VARIABLE_ISSUE}.",
984 /* Calculate how much this insn affects how many more insns we
985 can emit this cycle. Default is they all cost the same. */
988 "This hook is executed by the scheduler after it has scheduled an insn\n\
989 from the ready list. It should return the number of insns which can\n\
990 still be issued in the current cycle. The default is\n\
991 @samp{@w{@var{more} - 1}} for insns other than @code{CLOBBER} and\n\
992 @code{USE}, which normally are not counted against the issue rate.\n\
993 You should define this hook if some insns take more machine resources\n\
994 than others, so that fewer insns can follow them in the same cycle.\n\
995 @var{file} is either a null pointer, or a stdio stream to write any\n\
996 debug output to. @var{verbose} is the verbose level provided by\n\
997 @option{-fsched-verbose-@var{n}}. @var{insn} is the instruction that\n\
999 int, (FILE *file, int verbose, rtx_insn *insn, int more), NULL)
1001 /* Initialize machine-dependent scheduling code. */
1004 "This hook is executed by the scheduler at the beginning of each block of\n\
1005 instructions that are to be scheduled. @var{file} is either a null\n\
1006 pointer, or a stdio stream to write any debug output to. @var{verbose}\n\
1007 is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
1008 @var{max_ready} is the maximum number of insns in the current scheduling\n\
1009 region that can be live at the same time. This can be used to allocate\n\
1010 scratch space if it is needed, e.g.@: by @samp{TARGET_SCHED_REORDER}.",
1011 void, (FILE *file, int verbose, int max_ready), NULL)
1013 /* Finalize machine-dependent scheduling code. */
1016 "This hook is executed by the scheduler at the end of each block of\n\
1017 instructions that are to be scheduled. It can be used to perform\n\
1018 cleanup of any actions done by the other scheduling hooks. @var{file}\n\
1019 is either a null pointer, or a stdio stream to write any debug output\n\
1020 to. @var{verbose} is the verbose level provided by\n\
1021 @option{-fsched-verbose-@var{n}}.",
1022 void, (FILE *file, int verbose), NULL)
1024 /* Initialize machine-dependent function wide scheduling code. */
1027 "This hook is executed by the scheduler after function level initializations.\n\
1028 @var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1029 @var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
1030 @var{old_max_uid} is the maximum insn uid when scheduling begins.",
1031 void, (FILE *file, int verbose, int old_max_uid), NULL)
1033 /* Finalize machine-dependent function wide scheduling code. */
1036 "This is the cleanup hook corresponding to @code{TARGET_SCHED_INIT_GLOBAL}.\n\
1037 @var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1038 @var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.",
1039 void, (FILE *file, int verbose), NULL)
1041 /* Reorder insns in a machine-dependent fashion, in two different
1042 places. Default does nothing. */
1045 "This hook is executed by the scheduler after it has scheduled the ready\n\
1046 list, to allow the machine description to reorder it (for example to\n\
1047 combine two small instructions together on @samp{VLIW} machines).\n\
1048 @var{file} is either a null pointer, or a stdio stream to write any\n\
1049 debug output to. @var{verbose} is the verbose level provided by\n\
1050 @option{-fsched-verbose-@var{n}}. @var{ready} is a pointer to the ready\n\
1051 list of instructions that are ready to be scheduled. @var{n_readyp} is\n\
1052 a pointer to the number of elements in the ready list. The scheduler\n\
1053 reads the ready list in reverse order, starting with\n\
1054 @var{ready}[@var{*n_readyp} @minus{} 1] and going to @var{ready}[0]. @var{clock}\n\
1055 is the timer tick of the scheduler. You may modify the ready list and\n\
1056 the number of ready insns. The return value is the number of insns that\n\
1057 can issue this cycle; normally this is just @code{issue_rate}. See also\n\
1058 @samp{TARGET_SCHED_REORDER2}.",
1059 int, (FILE *file, int verbose, rtx_insn **ready, int *n_readyp, int clock), NULL)
1063 "Like @samp{TARGET_SCHED_REORDER}, but called at a different time. That\n\
1064 function is called whenever the scheduler starts a new cycle. This one\n\
1065 is called once per iteration over a cycle, immediately after\n\
1066 @samp{TARGET_SCHED_VARIABLE_ISSUE}; it can reorder the ready list and\n\
1067 return the number of insns to be scheduled in the same cycle. Defining\n\
1068 this hook can be useful if there are frequent situations where\n\
1069 scheduling one insn causes other insns to become ready in the same\n\
1070 cycle. These other insns can then be taken into account properly.",
1071 int, (FILE *file, int verbose, rtx_insn **ready, int *n_readyp, int clock), NULL)
1075 "This hook is used to check whether target platform supports macro fusion.",
1079 (macro_fusion_pair_p,
1080 "This hook is used to check whether two insns should be macro fused for\n\
1081 a target microarchitecture. If this hook returns true for the given insn pair\n\
1082 (@var{prev} and @var{curr}), the scheduler will put them into a sched\n\
1083 group, and they will not be scheduled apart. The two insns will be either\n\
1084 two SET insns or a compare and a conditional jump and this hook should\n\
1085 validate any dependencies needed to fuse the two insns together.",
1086 bool, (rtx_insn *prev, rtx_insn *curr), NULL)
1088 /* The following member value is a pointer to a function called
1089 after evaluation forward dependencies of insns in chain given
1090 by two parameter values (head and tail correspondingly). */
1092 (dependencies_evaluation_hook,
1093 "This hook is called after evaluation forward dependencies of insns in\n\
1094 chain given by two parameter values (@var{head} and @var{tail}\n\
1095 correspondingly) but before insns scheduling of the insn chain. For\n\
1096 example, it can be used for better insn classification if it requires\n\
1097 analysis of dependencies. This hook can use backward and forward\n\
1098 dependencies of the insn scheduler because they are already\n\
1100 void, (rtx_insn *head, rtx_insn *tail), NULL)
1102 /* The values of the following four members are pointers to functions
1103 used to simplify the automaton descriptions. dfa_pre_cycle_insn and
1104 dfa_post_cycle_insn give functions returning insns which are used to
1105 change the pipeline hazard recognizer state when the new simulated
1106 processor cycle correspondingly starts and finishes. The function
1107 defined by init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are
1108 used to initialize the corresponding insns. The default values of
1109 the members result in not changing the automaton state when the
1110 new simulated processor cycle correspondingly starts and finishes. */
1113 (init_dfa_pre_cycle_insn,
1114 "The hook can be used to initialize data used by the previous hook.",
1118 (dfa_pre_cycle_insn,
1119 "The hook returns an RTL insn. The automaton state used in the\n\
1120 pipeline hazard recognizer is changed as if the insn were scheduled\n\
1121 when the new simulated processor cycle starts. Usage of the hook may\n\
1122 simplify the automaton pipeline description for some @acronym{VLIW}\n\
1123 processors. If the hook is defined, it is used only for the automaton\n\
1124 based pipeline description. The default is not to change the state\n\
1125 when the new simulated processor cycle starts.",
1129 (init_dfa_post_cycle_insn,
1130 "The hook is analogous to @samp{TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN} but\n\
1131 used to initialize data used by the previous hook.",
1135 (dfa_post_cycle_insn,
1136 "The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1137 to changed the state as if the insn were scheduled when the new\n\
1138 simulated processor cycle finishes.",
1139 rtx_insn *, (void), NULL)
1141 /* The values of the following two members are pointers to
1142 functions used to simplify the automaton descriptions.
1143 dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called
1144 immediately before and after cycle is advanced. */
1147 (dfa_pre_advance_cycle,
1148 "The hook to notify target that the current simulated cycle is about to finish.\n\
1149 The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1150 to change the state in more complicated situations - e.g., when advancing\n\
1151 state on a single insn is not enough.",
1155 (dfa_post_advance_cycle,
1156 "The hook to notify target that new simulated cycle has just started.\n\
1157 The hook is analogous to @samp{TARGET_SCHED_DFA_POST_CYCLE_INSN} but used\n\
1158 to change the state in more complicated situations - e.g., when advancing\n\
1159 state on a single insn is not enough.",
1162 /* The following member value is a pointer to a function returning value
1163 which defines how many insns in queue `ready' will we try for
1164 multi-pass scheduling. If the member value is nonzero and the
1165 function returns positive value, the DFA based scheduler will make
1166 multi-pass scheduling for the first cycle. In other words, we will
1167 try to choose ready insn which permits to start maximum number of
1168 insns on the same cycle. */
1170 (first_cycle_multipass_dfa_lookahead,
1171 "This hook controls better choosing an insn from the ready insn queue\n\
1172 for the @acronym{DFA}-based insn scheduler. Usually the scheduler\n\
1173 chooses the first insn from the queue. If the hook returns a positive\n\
1174 value, an additional scheduler code tries all permutations of\n\
1175 @samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD ()}\n\
1176 subsequent ready insns to choose an insn whose issue will result in\n\
1177 maximal number of issued insns on the same cycle. For the\n\
1178 @acronym{VLIW} processor, the code could actually solve the problem of\n\
1179 packing simple insns into the @acronym{VLIW} insn. Of course, if the\n\
1180 rules of @acronym{VLIW} packing are described in the automaton.\n\
1182 This code also could be used for superscalar @acronym{RISC}\n\
1183 processors. Let us consider a superscalar @acronym{RISC} processor\n\
1184 with 3 pipelines. Some insns can be executed in pipelines @var{A} or\n\
1185 @var{B}, some insns can be executed only in pipelines @var{B} or\n\
1186 @var{C}, and one insn can be executed in pipeline @var{B}. The\n\
1187 processor may issue the 1st insn into @var{A} and the 2nd one into\n\
1188 @var{B}. In this case, the 3rd insn will wait for freeing @var{B}\n\
1189 until the next cycle. If the scheduler issues the 3rd insn the first,\n\
1190 the processor could issue all 3 insns per cycle.\n\
1192 Actually this code demonstrates advantages of the automaton based\n\
1193 pipeline hazard recognizer. We try quickly and easy many insn\n\
1194 schedules to choose the best one.\n\
1196 The default is no multipass scheduling.",
1199 /* The following member value is pointer to a function controlling
1200 what insns from the ready insn queue will be considered for the
1201 multipass insn scheduling. If the hook returns zero for insn
1202 passed as the parameter, the insn will be not chosen to be issued. */
1204 (first_cycle_multipass_dfa_lookahead_guard,
1206 This hook controls what insns from the ready insn queue will be\n\
1207 considered for the multipass insn scheduling. If the hook returns\n\
1208 zero for @var{insn}, the insn will be considered in multipass scheduling.\n\
1209 Positive return values will remove @var{insn} from consideration on\n\
1210 the current round of multipass scheduling.\n\
1211 Negative return values will remove @var{insn} from consideration for given\n\
1212 number of cycles.\n\
1213 Backends should be careful about returning non-zero for highest priority\n\
1214 instruction at position 0 in the ready list. @var{ready_index} is passed\n\
1215 to allow backends make correct judgements.\n\
1217 The default is that any ready insns can be chosen to be issued.",
1218 int, (rtx_insn *insn, int ready_index), NULL)
1220 /* This hook prepares the target for a new round of multipass
1222 DATA is a pointer to target-specific data used for multipass scheduling.
1223 READY_TRY and N_READY represent the current state of search in the
1224 optimization space. The target can filter out instructions that
1225 should not be tried during current round by setting corresponding
1226 elements in READY_TRY to non-zero.
1227 FIRST_CYCLE_INSN_P is true if this is the first round of multipass
1228 scheduling on current cycle. */
1230 (first_cycle_multipass_begin,
1231 "This hook prepares the target backend for a new round of multipass\n\
1233 void, (void *data, signed char *ready_try, int n_ready, bool first_cycle_insn_p),
1236 /* This hook is called when multipass scheduling evaluates instruction INSN.
1237 DATA is a pointer to target-specific data that can be used to record effects
1238 of INSN on CPU that are not described in DFA.
1239 READY_TRY and N_READY represent the current state of search in the
1240 optimization space. The target can filter out instructions that
1241 should not be tried after issuing INSN by setting corresponding
1242 elements in READY_TRY to non-zero.
1243 INSN is the instruction being evaluated.
1244 PREV_DATA is a pointer to target-specific data corresponding
1245 to a state before issuing INSN. */
1247 (first_cycle_multipass_issue,
1248 "This hook is called when multipass scheduling evaluates instruction INSN.",
1249 void, (void *data, signed char *ready_try, int n_ready, rtx_insn *insn,
1250 const void *prev_data), NULL)
1252 /* This hook is called when multipass scheduling backtracks from evaluation of
1253 instruction corresponding to DATA.
1254 DATA is a pointer to target-specific data that stores the effects
1255 of instruction from which the algorithm backtracks on CPU that are not
1257 READY_TRY and N_READY represent the current state of search in the
1258 optimization space. The target can filter out instructions that
1259 should not be tried after issuing INSN by setting corresponding
1260 elements in READY_TRY to non-zero. */
1262 (first_cycle_multipass_backtrack,
1263 "This is called when multipass scheduling backtracks from evaluation of\n\
1265 void, (const void *data, signed char *ready_try, int n_ready), NULL)
1267 /* This hook notifies the target about the result of the concluded current
1268 round of multipass scheduling.
1270 If DATA is non-NULL it points to target-specific data used for multipass
1271 scheduling which corresponds to instruction at the start of the chain of
1272 the winning solution. DATA is NULL when multipass scheduling cannot find
1273 a good enough solution on current cycle and decides to retry later,
1274 usually after advancing the cycle count. */
1276 (first_cycle_multipass_end,
1277 "This hook notifies the target about the result of the concluded current\n\
1278 round of multipass scheduling.",
1279 void, (const void *data), NULL)
1281 /* This hook is called to initialize target-specific data for multipass
1282 scheduling after it has been allocated.
1283 DATA is a pointer to target-specific data that stores the effects
1284 of instruction from which the algorithm backtracks on CPU that are not
1285 described in DFA. */
1287 (first_cycle_multipass_init,
1288 "This hook initializes target-specific data used in multipass scheduling.",
1289 void, (void *data), NULL)
1291 /* This hook is called to finalize target-specific data for multipass
1292 scheduling before it is deallocated.
1293 DATA is a pointer to target-specific data that stores the effects
1294 of instruction from which the algorithm backtracks on CPU that are not
1295 described in DFA. */
1297 (first_cycle_multipass_fini,
1298 "This hook finalizes target-specific data used in multipass scheduling.",
1299 void, (void *data), NULL)
1301 /* The following member value is pointer to a function called by
1302 the insn scheduler before issuing insn passed as the third
1303 parameter on given cycle. If the hook returns nonzero, the
1304 insn is not issued on given processors cycle. Instead of that,
1305 the processor cycle is advanced. If the value passed through
1306 the last parameter is zero, the insn ready queue is not sorted
1307 on the new cycle start as usually. The first parameter passes
1308 file for debugging output. The second one passes the scheduler
1309 verbose level of the debugging output. The forth and the fifth
1310 parameter values are correspondingly processor cycle on which
1311 the previous insn has been issued and the current processor cycle. */
1314 "This hook is called by the insn scheduler before issuing @var{insn}\n\
1315 on cycle @var{clock}. If the hook returns nonzero,\n\
1316 @var{insn} is not issued on this processor cycle. Instead,\n\
1317 the processor cycle is advanced. If *@var{sort_p}\n\
1318 is zero, the insn ready queue is not sorted on the new cycle\n\
1319 start as usually. @var{dump} and @var{verbose} specify the file and\n\
1320 verbosity level to use for debugging output.\n\
1321 @var{last_clock} and @var{clock} are, respectively, the\n\
1322 processor cycle on which the previous insn has been issued,\n\
1323 and the current processor cycle.",
1324 int, (FILE *dump, int verbose, rtx_insn *insn, int last_clock,
1325 int clock, int *sort_p),
1328 /* The following member value is a pointer to a function called by the
1329 insn scheduler. It should return true if there exists a dependence
1330 which is considered costly by the target, between the insn
1331 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
1332 the dep that represents the dependence between the two insns. The
1333 second argument is the cost of the dependence as estimated by
1334 the scheduler. The last argument is the distance in cycles
1335 between the already scheduled insn (first parameter) and the
1336 second insn (second parameter). */
1338 (is_costly_dependence,
1339 "This hook is used to define which dependences are considered costly by\n\
1340 the target, so costly that it is not advisable to schedule the insns that\n\
1341 are involved in the dependence too close to one another. The parameters\n\
1342 to this hook are as follows: The first parameter @var{_dep} is the dependence\n\
1343 being evaluated. The second parameter @var{cost} is the cost of the\n\
1344 dependence as estimated by the scheduler, and the third\n\
1345 parameter @var{distance} is the distance in cycles between the two insns.\n\
1346 The hook returns @code{true} if considering the distance between the two\n\
1347 insns the dependence between them is considered costly by the target,\n\
1348 and @code{false} otherwise.\n\
1350 Defining this hook can be useful in multiple-issue out-of-order machines,\n\
1351 where (a) it's practically hopeless to predict the actual data/resource\n\
1352 delays, however: (b) there's a better chance to predict the actual grouping\n\
1353 that will be formed, and (c) correctly emulating the grouping can be very\n\
1354 important. In such targets one may want to allow issuing dependent insns\n\
1355 closer to one another---i.e., closer than the dependence distance; however,\n\
1356 not in cases of ``costly dependences'', which this hooks allows to define.",
1357 bool, (struct _dep *_dep, int cost, int distance), NULL)
1359 /* The following member value is a pointer to a function called
1360 by the insn scheduler. This hook is called to notify the backend
1361 that new instructions were emitted. */
1364 "This hook is called by the insn scheduler after emitting a new instruction to\n\
1365 the instruction stream. The hook notifies a target backend to extend its\n\
1366 per instruction data structures.",
1369 /* Next 5 functions are for multi-point scheduling. */
1371 /* Allocate memory for scheduler context. */
1373 (alloc_sched_context,
1374 "Return a pointer to a store large enough to hold target scheduling context.",
1375 void *, (void), NULL)
1377 /* Fills the context from the local machine scheduler context. */
1379 (init_sched_context,
1380 "Initialize store pointed to by @var{tc} to hold target scheduling context.\n\
1381 It @var{clean_p} is true then initialize @var{tc} as if scheduler is at the\n\
1382 beginning of the block. Otherwise, copy the current context into @var{tc}.",
1383 void, (void *tc, bool clean_p), NULL)
1385 /* Sets local machine scheduler context to a saved value. */
1388 "Copy target scheduling context pointed to by @var{tc} to the current context.",
1389 void, (void *tc), NULL)
1391 /* Clears a scheduler context so it becomes like after init. */
1393 (clear_sched_context,
1394 "Deallocate internal data in target scheduling context pointed to by @var{tc}.",
1395 void, (void *tc), NULL)
1397 /* Frees the scheduler context. */
1399 (free_sched_context,
1400 "Deallocate a store for target scheduling context pointed to by @var{tc}.",
1401 void, (void *tc), NULL)
1403 /* The following member value is a pointer to a function called
1404 by the insn scheduler.
1405 The first parameter is an instruction, the second parameter is the type
1406 of the requested speculation, and the third parameter is a pointer to the
1407 speculative pattern of the corresponding type (set if return value == 1).
1409 -1, if there is no pattern, that will satisfy the requested speculation type,
1410 0, if current pattern satisfies the requested speculation type,
1411 1, if pattern of the instruction should be changed to the newly
1415 "This hook is called by the insn scheduler when @var{insn} has only\n\
1416 speculative dependencies and therefore can be scheduled speculatively.\n\
1417 The hook is used to check if the pattern of @var{insn} has a speculative\n\
1418 version and, in case of successful check, to generate that speculative\n\
1419 pattern. The hook should return 1, if the instruction has a speculative form,\n\
1420 or @minus{}1, if it doesn't. @var{request} describes the type of requested\n\
1421 speculation. If the return value equals 1 then @var{new_pat} is assigned\n\
1422 the generated speculative pattern.",
1423 int, (rtx_insn *insn, unsigned int dep_status, rtx *new_pat), NULL)
1425 /* The following member value is a pointer to a function called
1426 by the insn scheduler. It should return true if the check instruction
1427 passed as the parameter needs a recovery block. */
1430 "This hook is called by the insn scheduler during generation of recovery code\n\
1431 for @var{insn}. It should return @code{true}, if the corresponding check\n\
1432 instruction should branch to recovery code, or @code{false} otherwise.",
1433 bool, (unsigned int dep_status), NULL)
1435 /* The following member value is a pointer to a function called
1436 by the insn scheduler. It should return a pattern for the check
1438 The first parameter is a speculative instruction, the second parameter
1439 is the label of the corresponding recovery block (or null, if it is a
1440 simple check). The third parameter is the kind of speculation that
1441 is being performed. */
1444 "This hook is called by the insn scheduler to generate a pattern for recovery\n\
1445 check instruction. If @var{mutate_p} is zero, then @var{insn} is a\n\
1446 speculative instruction for which the check should be generated.\n\
1447 @var{label} is either a label of a basic block, where recovery code should\n\
1448 be emitted, or a null pointer, when requested check doesn't branch to\n\
1449 recovery code (a simple check). If @var{mutate_p} is nonzero, then\n\
1450 a pattern for a branchy check corresponding to a simple check denoted by\n\
1451 @var{insn} should be generated. In this case @var{label} can't be null.",
1452 rtx, (rtx_insn *insn, rtx_insn *label, unsigned int ds), NULL)
1454 /* The following member value is a pointer to a function that provides
1455 information about the speculation capabilities of the target.
1456 The parameter is a pointer to spec_info variable. */
1459 "This hook is used by the insn scheduler to find out what features should be\n\
1461 The structure *@var{spec_info} should be filled in by the target.\n\
1462 The structure describes speculation types that can be used in the scheduler.",
1463 void, (struct spec_info_def *spec_info), NULL)
1467 "Return speculation types of instruction @var{insn}.",
1468 unsigned int, (rtx_insn *insn), NULL)
1471 (get_insn_checked_ds,
1472 "Return speculation types that are checked for instruction @var{insn}",
1473 unsigned int, (rtx_insn *insn), NULL)
1476 (can_speculate_insn,
1477 "Some instructions should never be speculated by the schedulers, usually\n\
1478 because the instruction is too expensive to get this wrong. Often such\n\
1479 instructions have long latency, and often they are not fully modeled in the\n\
1480 pipeline descriptions. This hook should return @code{false} if @var{insn}\n\
1481 should not be speculated.",
1482 bool, (rtx_insn *insn), hook_bool_rtx_insn_true)
1486 "Return bool if rtx scanning should just skip current layer and\
1487 advance to the inner rtxes.",
1488 bool, (const_rtx x), NULL)
1490 /* The following member value is a pointer to a function that provides
1491 information about the target resource-based lower bound which is
1492 used by the swing modulo scheduler. The parameter is a pointer
1496 "This hook is called by the swing modulo scheduler to calculate a\n\
1497 resource-based lower bound which is based on the resources available in\n\
1498 the machine and the resources required by each instruction. The target\n\
1499 backend can use @var{g} to calculate such bound. A very simple lower\n\
1500 bound will be used in case this hook is not implemented: the total number\n\
1501 of instructions divided by the issue rate.",
1502 int, (struct ddg *g), NULL)
1504 /* The following member value is a function that initializes dispatch
1505 schedling and adds instructions to dispatch window according to its
1509 "This hook is called by Haifa Scheduler. It performs the operation specified\n\
1510 in its second parameter.",
1511 void, (rtx_insn *insn, int x),
1512 hook_void_rtx_insn_int)
1514 /* The following member value is a function that returns true is
1515 dispatch schedling is supported in hardware and condition passed
1516 as the second parameter is true. */
1519 "This hook is called by Haifa Scheduler. It returns true if dispatch scheduling\n\
1520 is supported in hardware and the condition specified in the parameter is true.",
1521 bool, (rtx_insn *insn, int x),
1522 hook_bool_rtx_insn_int_false)
1526 "True if the processor has an exposed pipeline, which means that not just\n\
1527 the order of instructions is important for correctness when scheduling, but\n\
1528 also the latencies of operations.",
1531 /* The following member value is a function that returns number
1532 of operations reassociator should try to put in parallel for
1533 statements of the given type. By default 1 is used. */
1535 (reassociation_width,
1536 "This hook is called by tree reassociator to determine a level of\n\
1537 parallelism required in output calculations chain.",
1538 int, (unsigned int opc, machine_mode mode),
1539 hook_int_uint_mode_1)
1541 /* The following member value is a function that returns priority for
1542 fusion of each instruction via pointer parameters. */
1545 "This hook is called by scheduling fusion pass. It calculates fusion\n\
1546 priorities for each instruction passed in by parameter. The priorities\n\
1547 are returned via pointer parameters.\n\
1549 @var{insn} is the instruction whose priorities need to be calculated.\n\
1550 @var{max_pri} is the maximum priority can be returned in any cases.\n\
1551 @var{fusion_pri} is the pointer parameter through which @var{insn}'s\n\
1552 fusion priority should be calculated and returned.\n\
1553 @var{pri} is the pointer parameter through which @var{insn}'s priority\n\
1554 should be calculated and returned.\n\
1556 Same @var{fusion_pri} should be returned for instructions which should\n\
1557 be scheduled together. Different @var{pri} should be returned for\n\
1558 instructions with same @var{fusion_pri}. @var{fusion_pri} is the major\n\
1559 sort key, @var{pri} is the minor sort key. All instructions will be\n\
1560 scheduled according to the two priorities. All priorities calculated\n\
1561 should be between 0 (exclusive) and @var{max_pri} (inclusive). To avoid\n\
1562 false dependencies, @var{fusion_pri} of instructions which need to be\n\
1563 scheduled together should be smaller than @var{fusion_pri} of irrelevant\n\
1566 Given below example:\n\
1575 ldr r16, [r2, 12]\n\
1577 @end smallexample\n\
1579 On targets like ARM/AArch64, the two pairs of consecutive loads should be\n\
1580 merged. Since peephole2 pass can't help in this case unless consecutive\n\
1581 loads are actually next to each other in instruction flow. That's where\n\
1582 this scheduling fusion pass works. This hook calculates priority for each\n\
1583 instruction based on its fustion type, like:\n\
1586 ldr r10, [r1, 4] ; fusion_pri=99, pri=96\n\
1587 add r4, r4, r10 ; fusion_pri=100, pri=100\n\
1588 ldr r15, [r2, 8] ; fusion_pri=98, pri=92\n\
1589 sub r5, r5, r15 ; fusion_pri=100, pri=100\n\
1590 ldr r11, [r1, 0] ; fusion_pri=99, pri=100\n\
1591 add r4, r4, r11 ; fusion_pri=100, pri=100\n\
1592 ldr r16, [r2, 12] ; fusion_pri=98, pri=88\n\
1593 sub r5, r5, r16 ; fusion_pri=100, pri=100\n\
1594 @end smallexample\n\
1596 Scheduling fusion pass then sorts all ready to issue instructions according\n\
1597 to the priorities. As a result, instructions of same fusion type will be\n\
1598 pushed together in instruction flow, like:\n\
1604 ldr r16, [r2, 12]\n\
1609 @end smallexample\n\
1611 Now peephole2 pass can simply merge the two pairs of loads.\n\
1613 Since scheduling fusion pass relies on peephole2 to do real fusion\n\
1614 work, it is only enabled by default when peephole2 is in effect.\n\
1616 This is firstly introduced on ARM/AArch64 targets, please refer to\n\
1617 the hook implementation for how different fusion types are supported.",
1618 void, (rtx_insn *insn, int max_pri, int *fusion_pri, int *pri), NULL)
1620 HOOK_VECTOR_END (sched)
1622 /* Functions relating to OpenMP SIMD and __attribute__((simd)) clones. */
1624 #define HOOK_PREFIX "TARGET_SIMD_CLONE_"
1625 HOOK_VECTOR (TARGET_SIMD_CLONE, simd_clone)
1628 (compute_vecsize_and_simdlen,
1629 "This hook should set @var{vecsize_mangle}, @var{vecsize_int}, @var{vecsize_float}\n\
1630 fields in @var{simd_clone} structure pointed by @var{clone_info} argument and also\n\
1631 @var{simdlen} field if it was previously 0.\n\
1632 The hook should return 0 if SIMD clones shouldn't be emitted,\n\
1633 or number of @var{vecsize_mangle} variants that should be emitted.",
1634 int, (struct cgraph_node *, struct cgraph_simd_clone *, tree, int), NULL)
1638 "This hook should add implicit @code{attribute(target(\"...\"))} attribute\n\
1639 to SIMD clone @var{node} if needed.",
1640 void, (struct cgraph_node *), NULL)
1644 "This hook should return -1 if SIMD clone @var{node} shouldn't be used\n\
1645 in vectorized loops in current function, or non-negative number if it is\n\
1646 usable. In that case, the smaller the number is, the more desirable it is\n\
1648 int, (struct cgraph_node *), NULL)
1650 HOOK_VECTOR_END (simd_clone)
1652 /* Functions relating to OpenMP SIMT vectorization transform. */
1654 #define HOOK_PREFIX "TARGET_SIMT_"
1655 HOOK_VECTOR (TARGET_SIMT, simt)
1659 "Return number of threads in SIMT thread group on the target.",
1662 HOOK_VECTOR_END (simt)
1664 /* Functions relating to OpenMP. */
1666 #define HOOK_PREFIX "TARGET_OMP_"
1667 HOOK_VECTOR (TARGET_OMP, omp)
1670 (device_kind_arch_isa,
1671 "Return 1 if @var{trait} @var{name} is present in the OpenMP context's\n\
1672 device trait set, return 0 if not present in any OpenMP context in the\n\
1673 whole translation unit, or -1 if not present in the current OpenMP context\n\
1674 but might be present in another OpenMP context in the same TU.",
1675 int, (enum omp_device_kind_arch_isa trait, const char *name), NULL)
1677 HOOK_VECTOR_END (omp)
1679 /* Functions relating to openacc. */
1681 #define HOOK_PREFIX "TARGET_GOACC_"
1682 HOOK_VECTOR (TARGET_GOACC, goacc)
1686 "This hook should check the launch dimensions provided for an OpenACC\n\
1687 compute region, or routine. Defaulted values are represented as -1\n\
1688 and non-constant values as 0. The @var{fn_level} is negative for the\n\
1689 function corresponding to the compute region. For a routine it is the\n\
1690 outermost level at which partitioned execution may be spawned. The hook\n\
1691 should verify non-default values. If DECL is NULL, global defaults\n\
1692 are being validated and unspecified defaults should be filled in.\n\
1693 Diagnostics should be issued as appropriate. Return\n\
1694 true, if changes have been made. You must override this hook to\n\
1695 provide dimensions larger than 1.",
1696 bool, (tree decl, int *dims, int fn_level, unsigned used),
1697 default_goacc_validate_dims)
1701 "This hook should return the maximum size of a particular dimension,\n\
1702 or zero if unbounded.",
1704 default_goacc_dim_limit)
1708 "This hook can be used to convert IFN_GOACC_FORK and IFN_GOACC_JOIN\n\
1709 function calls to target-specific gimple, or indicate whether they\n\
1710 should be retained. It is executed during the oacc_device_lower pass.\n\
1711 It should return true, if the call should be retained. It should\n\
1712 return false, if it is to be deleted (either because target-specific\n\
1713 gimple has been inserted before it, or there is no need for it).\n\
1714 The default hook returns false, if there are no RTL expanders for them.",
1715 bool, (gcall *call, const int *dims, bool is_fork),
1716 default_goacc_fork_join)
1720 "This hook is used by the oacc_transform pass to expand calls to the\n\
1721 @var{GOACC_REDUCTION} internal function, into a sequence of gimple\n\
1722 instructions. @var{call} is gimple statement containing the call to\n\
1723 the function. This hook removes statement @var{call} after the\n\
1724 expanded sequence has been inserted. This hook is also responsible\n\
1725 for allocating any storage for reductions when necessary.",
1726 void, (gcall *call),
1727 default_goacc_reduction)
1730 (adjust_private_decl,
1731 "This hook, if defined, is used by accelerator target back-ends to adjust\n\
1732 OpenACC variable declarations that should be made private to the given\n\
1733 parallelism level (i.e. @code{GOMP_DIM_GANG}, @code{GOMP_DIM_WORKER} or\n\
1734 @code{GOMP_DIM_VECTOR}). A typical use for this hook is to force variable\n\
1735 declarations at the @code{gang} level to reside in GPU shared memory.\n\
1737 You may also use the @code{TARGET_GOACC_EXPAND_VAR_DECL} hook if the\n\
1738 adjusted variable declaration needs to be expanded to RTL in a non-standard\n\
1740 tree, (tree var, int level),
1745 "This hook, if defined, is used by accelerator target back-ends to expand\n\
1746 specially handled kinds of @code{VAR_DECL} expressions. A particular use is\n\
1747 to place variables with specific attributes inside special accelarator\n\
1748 memories. A return value of @code{NULL} indicates that the target does not\n\
1749 handle this @code{VAR_DECL}, and normal RTL expanding is resumed.\n\
1751 Only define this hook if your accelerator target needs to expand certain\n\
1752 @code{VAR_DECL} nodes in a way that differs from the default. You can also adjust\n\
1753 private variables at OpenACC device-lowering time using the\n\
1754 @code{TARGET_GOACC_ADJUST_PRIVATE_DECL} target hook.",
1758 HOOK_VECTOR_END (goacc)
1760 /* Functions relating to vectorization. */
1762 #define HOOK_PREFIX "TARGET_VECTORIZE_"
1763 HOOK_VECTOR (TARGET_VECTORIZE, vectorize)
1765 /* The following member value is a pointer to a function called
1766 by the vectorizer, and return the decl of the target builtin
1769 (builtin_mask_for_load,
1770 "This hook should return the DECL of a function @var{f} that given an\n\
1771 address @var{addr} as an argument returns a mask @var{m} that can be\n\
1772 used to extract from two vectors the relevant data that resides in\n\
1773 @var{addr} in case @var{addr} is not properly aligned.\n\
1775 The autovectorizer, when vectorizing a load operation from an address\n\
1776 @var{addr} that may be unaligned, will generate two vector loads from\n\
1777 the two aligned addresses around @var{addr}. It then generates a\n\
1778 @code{REALIGN_LOAD} operation to extract the relevant data from the\n\
1779 two loaded vectors. The first two arguments to @code{REALIGN_LOAD},\n\
1780 @var{v1} and @var{v2}, are the two vectors, each of size @var{VS}, and\n\
1781 the third argument, @var{OFF}, defines how the data will be extracted\n\
1782 from these two vectors: if @var{OFF} is 0, then the returned vector is\n\
1783 @var{v2}; otherwise, the returned vector is composed from the last\n\
1784 @var{VS}-@var{OFF} elements of @var{v1} concatenated to the first\n\
1785 @var{OFF} elements of @var{v2}.\n\
1787 If this hook is defined, the autovectorizer will generate a call\n\
1788 to @var{f} (using the DECL tree that this hook returns) and will\n\
1789 use the return value of @var{f} as the argument @var{OFF} to\n\
1790 @code{REALIGN_LOAD}. Therefore, the mask @var{m} returned by @var{f}\n\
1791 should comply with the semantics expected by @code{REALIGN_LOAD}\n\
1793 If this hook is not defined, then @var{addr} will be used as\n\
1794 the argument @var{OFF} to @code{REALIGN_LOAD}, in which case the low\n\
1795 log2(@var{VS}) @minus{} 1 bits of @var{addr} will be considered.",
1798 /* Returns a built-in function that realizes the vectorized version of
1799 a target-independent function, or NULL_TREE if not available. */
1801 (builtin_vectorized_function,
1802 "This hook should return the decl of a function that implements the\n\
1803 vectorized variant of the function with the @code{combined_fn} code\n\
1804 @var{code} or @code{NULL_TREE} if such a function is not available.\n\
1805 The return type of the vectorized function shall be of vector type\n\
1806 @var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1807 tree, (unsigned code, tree vec_type_out, tree vec_type_in),
1808 default_builtin_vectorized_function)
1810 /* Returns a built-in function that realizes the vectorized version of
1811 a target-specific function, or NULL_TREE if not available. */
1813 (builtin_md_vectorized_function,
1814 "This hook should return the decl of a function that implements the\n\
1815 vectorized variant of target built-in function @code{fndecl}. The\n\
1816 return type of the vectorized function shall be of vector type\n\
1817 @var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1818 tree, (tree fndecl, tree vec_type_out, tree vec_type_in),
1819 default_builtin_md_vectorized_function)
1821 /* Cost of different vector/scalar statements in vectorization cost
1822 model. In case of misaligned vector loads and stores the cost depends
1823 on the data type and misalignment value. */
1825 (builtin_vectorization_cost,
1826 "Returns cost of different scalar or vector statements for vectorization cost model.\n\
1827 For vector memory operations the cost may depend on type (@var{vectype}) and\n\
1828 misalignment value (@var{misalign}).",
1829 int, (enum vect_cost_for_stmt type_of_cost, tree vectype, int misalign),
1830 default_builtin_vectorization_cost)
1833 (preferred_vector_alignment,
1834 "This hook returns the preferred alignment in bits for accesses to\n\
1835 vectors of type @var{type} in vectorized code. This might be less than\n\
1836 or greater than the ABI-defined value returned by\n\
1837 @code{TARGET_VECTOR_ALIGNMENT}. It can be equal to the alignment of\n\
1838 a single element, in which case the vectorizer will not try to optimize\n\
1841 The default hook returns @code{TYPE_ALIGN (@var{type})}, which is\n\
1842 correct for most targets.",
1843 poly_uint64, (const_tree type),
1844 default_preferred_vector_alignment)
1846 /* Return true if vector alignment is reachable (by peeling N
1847 iterations) for the given scalar type. */
1849 (vector_alignment_reachable,
1850 "Return true if vector alignment is reachable (by peeling N iterations) for the given scalar type @var{type}. @var{is_packed} is false if the scalar access using @var{type} is known to be naturally aligned.",
1851 bool, (const_tree type, bool is_packed),
1852 default_builtin_vector_alignment_reachable)
1856 "This hook is used to test whether the target can permute up to two\n\
1857 vectors of mode @var{mode} using the permutation vector @code{sel}, and\n\
1858 also to emit such a permutation. In the former case @var{in0}, @var{in1}\n\
1859 and @var{out} are all null. In the latter case @var{in0} and @var{in1} are\n\
1860 the source vectors and @var{out} is the destination vector; all three are\n\
1861 registers of mode @var{mode}. @var{in1} is the same as @var{in0} if\n\
1862 @var{sel} describes a permutation on one vector instead of two.\n\
1864 Return true if the operation is possible, emitting instructions for it\n\
1865 if rtxes are provided.\n\
1867 @cindex @code{vec_perm@var{m}} instruction pattern\n\
1868 If the hook returns false for a mode with multibyte elements, GCC will\n\
1869 try the equivalent byte operation. If that also fails, it will try forcing\n\
1870 the selector into a register and using the @var{vec_perm@var{mode}}\n\
1871 instruction pattern. There is no need for the hook to handle these two\n\
1872 implementation approaches itself.",
1873 bool, (machine_mode mode, rtx output, rtx in0, rtx in1,
1874 const vec_perm_indices &sel),
1877 /* Return true if the target supports misaligned store/load of a
1878 specific factor denoted in the third parameter. The last parameter
1879 is true if the access is defined in a packed struct. */
1881 (support_vector_misalignment,
1882 "This hook should return true if the target supports misaligned vector\n\
1883 store/load of a specific factor denoted in the @var{misalignment}\n\
1884 parameter. The vector store/load should be of machine mode @var{mode} and\n\
1885 the elements in the vectors should be of type @var{type}. @var{is_packed}\n\
1886 parameter is true if the memory access is defined in a packed struct.",
1888 (machine_mode mode, const_tree type, int misalignment, bool is_packed),
1889 default_builtin_support_vector_misalignment)
1891 /* Returns the preferred mode for SIMD operations for the specified
1894 (preferred_simd_mode,
1895 "This hook should return the preferred mode for vectorizing scalar\n\
1896 mode @var{mode}. The default is\n\
1897 equal to @code{word_mode}, because the vectorizer can do some\n\
1898 transformations even in absence of specialized @acronym{SIMD} hardware.",
1901 default_preferred_simd_mode)
1903 /* Returns the preferred mode for splitting SIMD reductions to. */
1906 "This hook should return the preferred mode to split the final reduction\n\
1907 step on @var{mode} to. The reduction is then carried out reducing upper\n\
1908 against lower halves of vectors recursively until the specified mode is\n\
1909 reached. The default is @var{mode} which means no splitting.",
1912 default_split_reduction)
1914 /* Returns a mask of vector sizes to iterate over when auto-vectorizing
1915 after processing the preferred one derived from preferred_simd_mode. */
1917 (autovectorize_vector_modes,
1918 "If using the mode returned by @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE}\n\
1919 is not the only approach worth considering, this hook should add one mode to\n\
1920 @var{modes} for each useful alternative approach. These modes are then\n\
1921 passed to @code{TARGET_VECTORIZE_RELATED_MODE} to obtain the vector mode\n\
1922 for a given element mode.\n\
1924 The modes returned in @var{modes} should use the smallest element mode\n\
1925 possible for the vectorization approach that they represent, preferring\n\
1926 integer modes over floating-poing modes in the event of a tie. The first\n\
1927 mode should be the @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE} for its\n\
1930 If @var{all} is true, add suitable vector modes even when they are generally\n\
1931 not expected to be worthwhile.\n\
1933 The hook returns a bitmask of flags that control how the modes in\n\
1934 @var{modes} are used. The flags are:\n\
1936 @item VECT_COMPARE_COSTS\n\
1937 Tells the loop vectorizer to try all the provided modes and pick the one\n\
1938 with the lowest cost. By default the vectorizer will choose the first\n\
1942 The hook does not need to do anything if the vector returned by\n\
1943 @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE} is the only one relevant\n\
1944 for autovectorization. The default implementation adds no modes and\n\
1947 (vector_modes *modes, bool all),
1948 default_autovectorize_vector_modes)
1952 "If a piece of code is using vector mode @var{vector_mode} and also wants\n\
1953 to operate on elements of mode @var{element_mode}, return the vector mode\n\
1954 it should use for those elements. If @var{nunits} is nonzero, ensure that\n\
1955 the mode has exactly @var{nunits} elements, otherwise pick whichever vector\n\
1956 size pairs the most naturally with @var{vector_mode}. Return an empty\n\
1957 @code{opt_machine_mode} if there is no supported vector mode with the\n\
1958 required properties.\n\
1960 There is no prescribed way of handling the case in which @var{nunits}\n\
1961 is zero. One common choice is to pick a vector mode with the same size\n\
1962 as @var{vector_mode}; this is the natural choice if the target has a\n\
1963 fixed vector size. Another option is to choose a vector mode with the\n\
1964 same number of elements as @var{vector_mode}; this is the natural choice\n\
1965 if the target has a fixed number of elements. Alternatively, the hook\n\
1966 might choose a middle ground, such as trying to keep the number of\n\
1967 elements as similar as possible while applying maximum and minimum\n\
1970 The default implementation uses @code{mode_for_vector} to find the\n\
1971 requested mode, returning a mode with the same size as @var{vector_mode}\n\
1972 when @var{nunits} is zero. This is the correct behavior for most targets.",
1974 (machine_mode vector_mode, scalar_mode element_mode, poly_uint64 nunits),
1975 default_vectorize_related_mode)
1977 /* Function to get a target mode for a vector mask. */
1980 "Return the mode to use for a vector mask that holds one boolean\n\
1981 result for each element of vector mode @var{mode}. The returned mask mode\n\
1982 can be a vector of integers (class @code{MODE_VECTOR_INT}), a vector of\n\
1983 booleans (class @code{MODE_VECTOR_BOOL}) or a scalar integer (class\n\
1984 @code{MODE_INT}). Return an empty @code{opt_machine_mode} if no such\n\
1985 mask mode exists.\n\
1987 The default implementation returns a @code{MODE_VECTOR_INT} with the\n\
1988 same size and number of elements as @var{mode}, if such a mode exists.",
1990 (machine_mode mode),
1991 default_get_mask_mode)
1993 /* Function to say whether a masked operation is expensive when the
1994 mask is all zeros. */
1996 (empty_mask_is_expensive,
1997 "This hook returns true if masked internal function @var{ifn} (really of\n\
1998 type @code{internal_fn}) should be considered expensive when the mask is\n\
1999 all zeros. GCC can then try to branch around the instruction instead.",
2002 default_empty_mask_is_expensive)
2004 /* Target builtin that implements vector gather operation. */
2007 "Target builtin that implements vector gather operation. @var{mem_vectype}\n\
2008 is the vector type of the load and @var{index_type} is scalar type of\n\
2009 the index, scaled by @var{scale}.\n\
2010 The default is @code{NULL_TREE} which means to not vectorize gather\n\
2013 (const_tree mem_vectype, const_tree index_type, int scale),
2016 /* Target builtin that implements vector scatter operation. */
2019 "Target builtin that implements vector scatter operation. @var{vectype}\n\
2020 is the vector type of the store and @var{index_type} is scalar type of\n\
2021 the index, scaled by @var{scale}.\n\
2022 The default is @code{NULL_TREE} which means to not vectorize scatter\n\
2025 (const_tree vectype, const_tree index_type, int scale),
2028 /* Target function to initialize the cost model for a loop or block. */
2031 "This hook should initialize target-specific data structures in preparation "
2032 "for modeling the costs of vectorizing a loop or basic block. The default "
2033 "allocates three unsigned integers for accumulating costs for the prologue, "
2034 "body, and epilogue of the loop or basic block. If @var{loop_info} is "
2035 "non-NULL, it identifies the loop being vectorized; otherwise a single block "
2036 "is being vectorized. If @var{costing_for_scalar} is true, it indicates the "
2037 "current cost model is for the scalar version of a loop or block; otherwise "
2038 "it is for the vector version.",
2040 (class loop *loop_info, bool costing_for_scalar),
2043 /* Target function to record N statements of the given kind using the
2044 given vector type within the cost model data for the current loop or
2048 "This hook should update the target-specific @var{data} in response to "
2049 "adding @var{count} copies of the given @var{kind} of statement to a "
2050 "loop or basic block. The default adds the builtin vectorizer cost for "
2051 "the copies of the statement to the accumulator specified by @var{where}, "
2052 "(the prologue, body, or epilogue) and returns the amount added. The "
2053 "return value should be viewed as a tentative cost that may later be "
2056 (class vec_info *, void *data, int count, enum vect_cost_for_stmt kind,
2057 class _stmt_vec_info *stmt_info, tree vectype, int misalign,
2058 enum vect_cost_model_location where),
2059 default_add_stmt_cost)
2061 /* Target function to calculate the total cost of the current vectorized
2065 "This hook should complete calculations of the cost of vectorizing a loop "
2066 "or basic block based on @var{data}, and return the prologue, body, and "
2067 "epilogue costs as unsigned integers. The default returns the value of "
2068 "the three accumulators.",
2070 (void *data, unsigned *prologue_cost, unsigned *body_cost,
2071 unsigned *epilogue_cost),
2072 default_finish_cost)
2074 /* Function to delete target-specific cost modeling data. */
2077 "This hook should release @var{data} and any related data structures "
2078 "allocated by TARGET_VECTORIZE_INIT_COST. The default releases the "
2082 default_destroy_cost_data)
2084 HOOK_VECTOR_END (vectorize)
2087 #define HOOK_PREFIX "TARGET_"
2090 (preferred_else_value,
2091 "This hook returns the target's preferred final argument for a call\n\
2092 to conditional internal function @var{ifn} (really of type\n\
2093 @code{internal_fn}). @var{type} specifies the return type of the\n\
2094 function and @var{ops} are the operands to the conditional operation,\n\
2095 of which there are @var{nops}.\n\
2097 For example, if @var{ifn} is @code{IFN_COND_ADD}, the hook returns\n\
2098 a value of type @var{type} that should be used when @samp{@var{ops}[0]}\n\
2099 and @samp{@var{ops}[1]} are conditionally added together.\n\
2101 This hook is only relevant if the target supports conditional patterns\n\
2102 like @code{cond_add@var{m}}. The default implementation returns a zero\n\
2103 constant of type @var{type}.",
2105 (unsigned ifn, tree type, unsigned nops, tree *ops),
2106 default_preferred_else_value)
2109 (record_offload_symbol,
2110 "Used when offloaded functions are seen in the compilation unit and no named\n\
2111 sections are available. It is called once for each symbol that must be\n\
2112 recorded in the offload function and variable table.",
2117 (absolute_biggest_alignment,
2118 "If defined, this target hook specifies the absolute biggest alignment\n\
2119 that a type or variable can have on this machine, otherwise,\n\
2120 @code{BIGGEST_ALIGNMENT} is used.",
2121 HOST_WIDE_INT, BIGGEST_ALIGNMENT)
2123 /* Allow target specific overriding of option settings after options have
2124 been changed by an attribute or pragma or when it is reset at the
2125 end of the code affected by an attribute or pragma. */
2127 (override_options_after_change,
2128 "This target function is similar to the hook @code{TARGET_OPTION_OVERRIDE}\n\
2129 but is called when the optimize level is changed via an attribute or\n\
2130 pragma or when it is reset at the end of the code affected by the\n\
2131 attribute or pragma. It is not called at the beginning of compilation\n\
2132 when @code{TARGET_OPTION_OVERRIDE} is called so if you want to perform these\n\
2133 actions then, you should have @code{TARGET_OPTION_OVERRIDE} call\n\
2134 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}.",
2140 "Used when writing out the list of options into an LTO file. It should\n\
2141 translate any relevant target-specific options (such as the ABI in use)\n\
2142 into one of the @option{-foffload} options that exist as a common interface\n\
2143 to express such options. It should return a string containing these options,\n\
2144 separated by spaces, which the caller will free.\n",
2145 char *, (void), hook_charptr_void_null)
2148 (eh_return_filter_mode,
2149 "Return machine mode for filter value.",
2150 scalar_int_mode, (void),
2151 default_eh_return_filter_mode)
2153 /* Return machine mode for libgcc expanded cmp instructions. */
2155 (libgcc_cmp_return_mode,
2156 "This target hook should return the mode to be used for the return value\n\
2157 of compare instructions expanded to libgcc calls. If not defined\n\
2158 @code{word_mode} is returned which is the right choice for a majority of\n\
2160 scalar_int_mode, (void),
2161 default_libgcc_cmp_return_mode)
2163 /* Return machine mode for libgcc expanded shift instructions. */
2165 (libgcc_shift_count_mode,
2166 "This target hook should return the mode to be used for the shift count operand\n\
2167 of shift instructions expanded to libgcc calls. If not defined\n\
2168 @code{word_mode} is returned which is the right choice for a majority of\n\
2170 scalar_int_mode, (void),
2171 default_libgcc_shift_count_mode)
2173 /* Return machine mode to be used for _Unwind_Word type. */
2176 "Return machine mode to be used for @code{_Unwind_Word} type.\n\
2177 The default is to use @code{word_mode}.",
2178 scalar_int_mode, (void),
2179 default_unwind_word_mode)
2181 /* Given two decls, merge their attributes and return the result. */
2183 (merge_decl_attributes,
2184 "Define this target hook if the merging of decl attributes needs special\n\
2185 handling. If defined, the result is a list of the combined\n\
2186 @code{DECL_ATTRIBUTES} of @var{olddecl} and @var{newdecl}.\n\
2187 @var{newdecl} is a duplicate declaration of @var{olddecl}. Examples of\n\
2188 when this is needed are when one attribute overrides another, or when an\n\
2189 attribute is nullified by a subsequent definition. This function may\n\
2190 call @code{merge_attributes} to handle machine-independent merging.\n\
2192 @findex TARGET_DLLIMPORT_DECL_ATTRIBUTES\n\
2193 If the only target-specific handling you require is @samp{dllimport}\n\
2194 for Microsoft Windows targets, you should define the macro\n\
2195 @code{TARGET_DLLIMPORT_DECL_ATTRIBUTES} to @code{1}. The compiler\n\
2196 will then define a function called\n\
2197 @code{merge_dllimport_decl_attributes} which can then be defined as\n\
2198 the expansion of @code{TARGET_MERGE_DECL_ATTRIBUTES}. You can also\n\
2199 add @code{handle_dll_attribute} in the attribute table for your port\n\
2200 to perform initial processing of the @samp{dllimport} and\n\
2201 @samp{dllexport} attributes. This is done in @file{i386/cygwin.h} and\n\
2202 @file{i386/i386.c}, for example.",
2203 tree, (tree olddecl, tree newdecl),
2204 merge_decl_attributes)
2206 /* Given two types, merge their attributes and return the result. */
2208 (merge_type_attributes,
2209 "Define this target hook if the merging of type attributes needs special\n\
2210 handling. If defined, the result is a list of the combined\n\
2211 @code{TYPE_ATTRIBUTES} of @var{type1} and @var{type2}. It is assumed\n\
2212 that @code{comptypes} has already been called and returned 1. This\n\
2213 function may call @code{merge_attributes} to handle machine-independent\n\
2215 tree, (tree type1, tree type2),
2216 merge_type_attributes)
2218 /* Table of machine attributes and functions to handle them.
2222 "If defined, this target hook points to an array of @samp{struct\n\
2223 attribute_spec} (defined in @file{tree-core.h}) specifying the machine\n\
2224 specific attributes for this target and some of the restrictions on the\n\
2225 entities to which these attributes are applied and the arguments they\n\
2227 const struct attribute_spec *, NULL)
2229 /* Return true iff attribute NAME expects a plain identifier as its first
2232 (attribute_takes_identifier_p,
2233 "If defined, this target hook is a function which returns true if the\n\
2234 machine-specific attribute named @var{name} expects an identifier\n\
2235 given as its first argument to be passed on as a plain identifier, not\n\
2236 subjected to name lookup. If this is not defined, the default is\n\
2237 false for all machine-specific attributes.",
2238 bool, (const_tree name),
2239 hook_bool_const_tree_false)
2241 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
2242 one if they are compatible and two if they are nearly compatible
2243 (which causes a warning to be generated). */
2245 (comp_type_attributes,
2246 "If defined, this target hook is a function which returns zero if the attributes on\n\
2247 @var{type1} and @var{type2} are incompatible, one if they are compatible,\n\
2248 and two if they are nearly compatible (which causes a warning to be\n\
2249 generated). If this is not defined, machine-specific attributes are\n\
2250 supposed always to be compatible.",
2251 int, (const_tree type1, const_tree type2),
2252 hook_int_const_tree_const_tree_1)
2254 /* Assign default attributes to the newly defined TYPE. */
2256 (set_default_type_attributes,
2257 "If defined, this target hook is a function which assigns default attributes to\n\
2258 the newly defined @var{type}.",
2262 /* Insert attributes on the newly created DECL. */
2265 "Define this target hook if you want to be able to add attributes to a decl\n\
2266 when it is being created. This is normally useful for back ends which\n\
2267 wish to implement a pragma by using the attributes which correspond to\n\
2268 the pragma's effect. The @var{node} argument is the decl which is being\n\
2269 created. The @var{attr_ptr} argument is a pointer to the attribute list\n\
2270 for this decl. The list itself should not be modified, since it may be\n\
2271 shared with other decls, but attributes may be chained on the head of\n\
2272 the list and @code{*@var{attr_ptr}} modified to point to the new\n\
2273 attributes, or a copy of the list may be made if further changes are\n\
2275 void, (tree node, tree *attr_ptr),
2276 hook_void_tree_treeptr)
2278 /* Perform additional target-specific processing of generic attributes. */
2280 (handle_generic_attribute,
2281 "Define this target hook if you want to be able to perform additional\n\
2282 target-specific processing of an attribute which is handled generically\n\
2283 by a front end. The arguments are the same as those which are passed to\n\
2284 attribute handlers. So far this only affects the @var{noinit} and\n\
2285 @var{section} attribute.",
2286 tree, (tree *node, tree name, tree args, int flags, bool *no_add_attrs),
2287 hook_tree_treeptr_tree_tree_int_boolptr_null)
2289 /* Return true if FNDECL (which has at least one machine attribute)
2290 can be inlined despite its machine attributes, false otherwise. */
2292 (function_attribute_inlinable_p,
2293 "@cindex inlining\n\
2294 This target hook returns @code{true} if it is OK to inline @var{fndecl}\n\
2295 into the current function, despite its having target-specific\n\
2296 attributes, @code{false} otherwise. By default, if a function has a\n\
2297 target specific attribute attached to it, it will not be inlined.",
2298 bool, (const_tree fndecl),
2299 hook_bool_const_tree_false)
2301 /* Return true if bitfields in RECORD_TYPE should follow the
2302 Microsoft Visual C++ bitfield layout rules. */
2304 (ms_bitfield_layout_p,
2305 "This target hook returns @code{true} if bit-fields in the given\n\
2306 @var{record_type} are to be laid out following the rules of Microsoft\n\
2307 Visual C/C++, namely: (i) a bit-field won't share the same storage\n\
2308 unit with the previous bit-field if their underlying types have\n\
2309 different sizes, and the bit-field will be aligned to the highest\n\
2310 alignment of the underlying types of itself and of the previous\n\
2311 bit-field; (ii) a zero-sized bit-field will affect the alignment of\n\
2312 the whole enclosing structure, even if it is unnamed; except that\n\
2313 (iii) a zero-sized bit-field will be disregarded unless it follows\n\
2314 another bit-field of nonzero size. If this hook returns @code{true},\n\
2315 other macros that control bit-field layout are ignored.\n\
2317 When a bit-field is inserted into a packed record, the whole size\n\
2318 of the underlying type is used by one or more same-size adjacent\n\
2319 bit-fields (that is, if its long:3, 32 bits is used in the record,\n\
2320 and any additional adjacent long bit-fields are packed into the same\n\
2321 chunk of 32 bits. However, if the size changes, a new field of that\n\
2322 size is allocated). In an unpacked record, this is the same as using\n\
2323 alignment, but not equivalent when packing.\n\
2325 If both MS bit-fields and @samp{__attribute__((packed))} are used,\n\
2326 the latter will take precedence. If @samp{__attribute__((packed))} is\n\
2327 used on a single field when MS bit-fields are in use, it will take\n\
2328 precedence for that field, but the alignment of the rest of the structure\n\
2329 may affect its placement.",
2330 bool, (const_tree record_type),
2331 hook_bool_const_tree_false)
2333 /* For now this is only an interface to WORDS_BIG_ENDIAN for
2334 target-independent code like the front ends, need performance testing
2335 before switching completely to the target hook. */
2340 targhook_words_big_endian)
2342 /* Likewise for FLOAT_WORDS_BIG_ENDIAN. */
2344 (float_words_big_endian,
2347 targhook_float_words_big_endian)
2350 (float_exceptions_rounding_supported_p,
2351 "Returns true if the target supports IEEE 754 floating-point exceptions\
2352 and rounding modes, false otherwise. This is intended to relate to the\
2353 @code{float} and @code{double} types, but not necessarily @code{long double}.\
2354 By default, returns true if the @code{adddf3} instruction pattern is\
2355 available and false otherwise, on the assumption that hardware floating\
2356 point supports exceptions and rounding modes but software floating point\
2359 default_float_exceptions_rounding_supported_p)
2361 /* True if the target supports decimal floating point. */
2363 (decimal_float_supported_p,
2364 "Returns true if the target supports decimal floating point.",
2366 default_decimal_float_supported_p)
2368 /* True if the target supports fixed-point. */
2370 (fixed_point_supported_p,
2371 "Returns true if the target supports fixed-point arithmetic.",
2373 default_fixed_point_supported_p)
2375 /* Return true if anonymous bitfields affect structure alignment. */
2377 (align_anon_bitfield,
2378 "When @code{PCC_BITFIELD_TYPE_MATTERS} is true this hook will determine\n\
2379 whether unnamed bitfields affect the alignment of the containing\n\
2380 structure. The hook should return true if the structure should inherit\n\
2381 the alignment requirements of an unnamed bitfield's type.",
2383 hook_bool_void_false)
2385 /* Return true if volatile bitfields should use the narrowest type possible.
2386 Return false if they should use the container type. */
2388 (narrow_volatile_bitfield,
2389 "This target hook should return @code{true} if accesses to volatile bitfields\n\
2390 should use the narrowest mode possible. It should return @code{false} if\n\
2391 these accesses should use the bitfield container type.\n\
2393 The default is @code{false}.",
2395 hook_bool_void_false)
2397 /* Set up target-specific built-in functions. */
2400 "Define this hook if you have any machine-specific built-in functions\n\
2401 that need to be defined. It should be a function that performs the\n\
2404 Machine specific built-in functions can be useful to expand special machine\n\
2405 instructions that would otherwise not normally be generated because\n\
2406 they have no equivalent in the source language (for example, SIMD vector\n\
2407 instructions or prefetch instructions).\n\
2409 To create a built-in function, call the function\n\
2410 @code{lang_hooks.builtin_function}\n\
2411 which is defined by the language front end. You can use any type nodes set\n\
2412 up by @code{build_common_tree_nodes};\n\
2413 only language front ends that use those two functions will call\n\
2414 @samp{TARGET_INIT_BUILTINS}.",
2418 /* Initialize (if INITIALIZE_P is true) and return the target-specific
2419 built-in function decl for CODE.
2420 Return NULL if that is not possible. Return error_mark_node if CODE
2421 is outside of the range of valid target builtin function codes. */
2424 "Define this hook if you have any machine-specific built-in functions\n\
2425 that need to be defined. It should be a function that returns the\n\
2426 builtin function declaration for the builtin function code @var{code}.\n\
2427 If there is no such builtin and it cannot be initialized at this time\n\
2428 if @var{initialize_p} is true the function should return @code{NULL_TREE}.\n\
2429 If @var{code} is out of range the function should return\n\
2430 @code{error_mark_node}.",
2431 tree, (unsigned code, bool initialize_p), NULL)
2433 /* Expand a target-specific builtin. */
2437 Expand a call to a machine specific built-in function that was set up by\n\
2438 @samp{TARGET_INIT_BUILTINS}. @var{exp} is the expression for the\n\
2439 function call; the result should go to @var{target} if that is\n\
2440 convenient, and have mode @var{mode} if that is convenient.\n\
2441 @var{subtarget} may be used as the target for computing one of\n\
2442 @var{exp}'s operands. @var{ignore} is nonzero if the value is to be\n\
2443 ignored. This function should return the result of the call to the\n\
2444 built-in function.",
2446 (tree exp, rtx target, rtx subtarget, machine_mode mode, int ignore),
2447 default_expand_builtin)
2449 /* Select a replacement for a target-specific builtin. This is done
2450 *before* regular type checking, and so allows the target to
2451 implement a crude form of function overloading. The result is a
2452 complete expression that implements the operation. PARAMS really
2453 has type VEC(tree,gc)*, but we don't want to include tree.h here. */
2455 (resolve_overloaded_builtin,
2456 "Select a replacement for a machine specific built-in function that\n\
2457 was set up by @samp{TARGET_INIT_BUILTINS}. This is done\n\
2458 @emph{before} regular type checking, and so allows the target to\n\
2459 implement a crude form of function overloading. @var{fndecl} is the\n\
2460 declaration of the built-in function. @var{arglist} is the list of\n\
2461 arguments passed to the built-in function. The result is a\n\
2462 complete expression that implements the operation, usually\n\
2463 another @code{CALL_EXPR}.\n\
2464 @var{arglist} really has type @samp{VEC(tree,gc)*}",
2465 tree, (unsigned int /*location_t*/ loc, tree fndecl, void *arglist), NULL)
2468 (check_builtin_call,
2469 "Perform semantic checking on a call to a machine-specific built-in\n\
2470 function after its arguments have been constrained to the function\n\
2471 signature. Return true if the call is valid, otherwise report an error\n\
2472 and return false.\n\
2474 This hook is called after @code{TARGET_RESOLVE_OVERLOADED_BUILTIN}.\n\
2475 The call was originally to built-in function @var{orig_fndecl},\n\
2476 but after the optional @code{TARGET_RESOLVE_OVERLOADED_BUILTIN}\n\
2477 step is now to built-in function @var{fndecl}. @var{loc} is the\n\
2478 location of the call and @var{args} is an array of function arguments,\n\
2479 of which there are @var{nargs}. @var{arg_loc} specifies the location\n\
2481 bool, (location_t loc, vec<location_t> arg_loc, tree fndecl,
2482 tree orig_fndecl, unsigned int nargs, tree *args),
2485 /* Fold a target-specific builtin to a tree valid for both GIMPLE
2489 "Fold a call to a machine specific built-in function that was set up by\n\
2490 @samp{TARGET_INIT_BUILTINS}. @var{fndecl} is the declaration of the\n\
2491 built-in function. @var{n_args} is the number of arguments passed to\n\
2492 the function; the arguments themselves are pointed to by @var{argp}.\n\
2493 The result is another tree, valid for both GIMPLE and GENERIC,\n\
2494 containing a simplified expression for the call's result. If\n\
2495 @var{ignore} is true the value will be ignored.",
2496 tree, (tree fndecl, int n_args, tree *argp, bool ignore),
2497 hook_tree_tree_int_treep_bool_null)
2499 /* Fold a target-specific builtin to a valid GIMPLE tree. */
2501 (gimple_fold_builtin,
2502 "Fold a call to a machine specific built-in function that was set up\n\
2503 by @samp{TARGET_INIT_BUILTINS}. @var{gsi} points to the gimple\n\
2504 statement holding the function call. Returns true if any change\n\
2505 was made to the GIMPLE stream.",
2506 bool, (gimple_stmt_iterator *gsi),
2507 hook_bool_gsiptr_false)
2509 /* Target hook is used to compare the target attributes in two functions to
2510 determine which function's features get higher priority. This is used
2511 during function multi-versioning to figure out the order in which two
2512 versions must be dispatched. A function version with a higher priority
2513 is checked for dispatching earlier. DECL1 and DECL2 are
2514 the two function decls that will be compared. It returns positive value
2515 if DECL1 is higher priority, negative value if DECL2 is higher priority
2516 and 0 if they are the same. */
2518 (compare_version_priority,
2519 "This hook is used to compare the target attributes in two functions to\n\
2520 determine which function's features get higher priority. This is used\n\
2521 during function multi-versioning to figure out the order in which two\n\
2522 versions must be dispatched. A function version with a higher priority\n\
2523 is checked for dispatching earlier. @var{decl1} and @var{decl2} are\n\
2524 the two function decls that will be compared.",
2525 int, (tree decl1, tree decl2), NULL)
2527 /* Target hook is used to generate the dispatcher logic to invoke the right
2528 function version at run-time for a given set of function versions.
2529 ARG points to the callgraph node of the dispatcher function whose body
2530 must be generated. */
2532 (generate_version_dispatcher_body,
2533 "This hook is used to generate the dispatcher logic to invoke the right\n\
2534 function version at run-time for a given set of function versions.\n\
2535 @var{arg} points to the callgraph node of the dispatcher function whose\n\
2536 body must be generated.",
2537 tree, (void *arg), NULL)
2539 /* Target hook is used to get the dispatcher function for a set of function
2540 versions. The dispatcher function is called to invoke the right function
2541 version at run-time. DECL is one version from a set of semantically
2542 identical versions. */
2544 (get_function_versions_dispatcher,
2545 "This hook is used to get the dispatcher function for a set of function\n\
2546 versions. The dispatcher function is called to invoke the right function\n\
2547 version at run-time. @var{decl} is one version from a set of semantically\n\
2548 identical versions.",
2549 tree, (void *decl), NULL)
2551 /* Returns a code for a target-specific builtin that implements
2552 reciprocal of a target-specific function, or NULL_TREE if not available. */
2554 (builtin_reciprocal,
2555 "This hook should return the DECL of a function that implements the\n\
2556 reciprocal of the machine-specific builtin function @var{fndecl}, or\n\
2557 @code{NULL_TREE} if such a function is not available.",
2558 tree, (tree fndecl),
2559 default_builtin_reciprocal)
2561 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
2562 string containing the C++ mangling for TYPE. In all other cases, return
2566 "If your target defines any fundamental types, or any types your target\n\
2567 uses should be mangled differently from the default, define this hook\n\
2568 to return the appropriate encoding for these types as part of a C++\n\
2569 mangled name. The @var{type} argument is the tree structure representing\n\
2570 the type to be mangled. The hook may be applied to trees which are\n\
2571 not target-specific fundamental types; it should return @code{NULL}\n\
2572 for all such types, as well as arguments it does not recognize. If the\n\
2573 return value is not @code{NULL}, it must point to a statically-allocated\n\
2576 Target-specific fundamental types might be new fundamental types or\n\
2577 qualified versions of ordinary fundamental types. Encode new\n\
2578 fundamental types as @samp{@w{u @var{n} @var{name}}}, where @var{name}\n\
2579 is the name used for the type in source code, and @var{n} is the\n\
2580 length of @var{name} in decimal. Encode qualified versions of\n\
2581 ordinary types as @samp{@w{U @var{n} @var{name} @var{code}}}, where\n\
2582 @var{name} is the name used for the type qualifier in source code,\n\
2583 @var{n} is the length of @var{name} as above, and @var{code} is the\n\
2584 code used to represent the unqualified version of this type. (See\n\
2585 @code{write_builtin_type} in @file{cp/mangle.c} for the list of\n\
2586 codes.) In both cases the spaces are for clarity; do not include any\n\
2587 spaces in your string.\n\
2589 This hook is applied to types prior to typedef resolution. If the mangled\n\
2590 name for a particular type depends only on that type's main variant, you\n\
2591 can perform typedef resolution yourself using @code{TYPE_MAIN_VARIANT}\n\
2594 The default version of this hook always returns @code{NULL}, which is\n\
2595 appropriate for a target that does not define any new fundamental\n\
2597 const char *, (const_tree type),
2598 hook_constcharptr_const_tree_null)
2600 /* Make any adjustments to libfunc names needed for this target. */
2603 "This hook should declare additional library routines or rename\n\
2604 existing ones, using the functions @code{set_optab_libfunc} and\n\
2605 @code{init_one_libfunc} defined in @file{optabs.c}.\n\
2606 @code{init_optabs} calls this macro after initializing all the normal\n\
2607 library routines.\n\
2609 The default is to do nothing. Most ports don't need to define this hook.",
2613 /* Add a __gnu_ prefix to library functions rather than just __. */
2615 (libfunc_gnu_prefix,
2616 "If false (the default), internal library routines start with two\n\
2617 underscores. If set to true, these routines start with @code{__gnu_}\n\
2618 instead. E.g., @code{__muldi3} changes to @code{__gnu_muldi3}. This\n\
2619 currently only affects functions defined in @file{libgcc2.c}. If this\n\
2620 is set to true, the @file{tm.h} file must also\n\
2621 @code{#define LIBGCC2_GNU_PREFIX}.",
2624 /* Given a decl, a section name, and whether the decl initializer
2625 has relocs, choose attributes for the section. */
2626 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
2628 (section_type_flags,
2629 "Choose a set of section attributes for use by @code{TARGET_ASM_NAMED_SECTION}\n\
2630 based on a variable or function decl, a section name, and whether or not the\n\
2631 declaration's initializer may contain runtime relocations. @var{decl} may be\n\
2632 null, in which case read-write data should be assumed.\n\
2634 The default version of this function handles choosing code vs data,\n\
2635 read-only vs read-write data, and @code{flag_pic}. You should only\n\
2636 need to override this if your target has special flags that might be\n\
2637 set via @code{__attribute__}.",
2638 unsigned int, (tree decl, const char *name, int reloc),
2639 default_section_type_flags)
2643 "This hook determines whether a function from a class of functions\n\
2644 @var{fn_class} is present in the target C library. If @var{type} is NULL,\n\
2645 the caller asks for support for all standard (float, double, long double)\n\
2646 types. If @var{type} is non-NULL, the caller asks for support for a\n\
2648 bool, (enum function_class fn_class, tree type),
2649 default_libc_has_function)
2652 (libc_has_fast_function,
2653 "This hook determines whether a function from a class of functions\n\
2654 @code{(enum function_class)}@var{fcode} has a fast implementation.",
2656 default_libc_has_fast_function)
2658 /* True if new jumps cannot be created, to replace existing ones or
2659 not, at the current point in the compilation. */
2661 (cannot_modify_jumps_p,
2662 "This target hook returns @code{true} past the point in which new jump\n\
2663 instructions could be created. On machines that require a register for\n\
2664 every jump such as the SHmedia ISA of SH5, this point would typically be\n\
2665 reload, so this target hook should be defined to a function such as:\n\
2669 cannot_modify_jumps_past_reload_p ()\n\
2671 return (reload_completed || reload_in_progress);\n\
2675 hook_bool_void_false)
2677 /* True if FOLLOWER may be modified to follow FOLLOWEE. */
2680 "FOLLOWER and FOLLOWEE are JUMP_INSN instructions;\
2681 return true if FOLLOWER may be modified to follow FOLLOWEE;\
2682 false, if it can't.\
2683 For example, on some targets, certain kinds of branches can't be made to\
2684 follow through a hot/cold partitioning.",
2685 bool, (const rtx_insn *follower, const rtx_insn *followee),
2686 hook_bool_const_rtx_insn_const_rtx_insn_true)
2688 /* Return true if the target supports conditional execution. */
2690 (have_conditional_execution,
2691 "This target hook returns true if the target supports conditional execution.\n\
2692 This target hook is required only when the target has several different\n\
2693 modes and they have different conditional execution capability, such as ARM.",
2695 default_have_conditional_execution)
2699 "This function prepares to emit a comparison insn for the first compare in a\n\
2700 sequence of conditional comparisions. It returns an appropriate comparison\n\
2701 with @code{CC} for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2702 The insns to prepare the compare are saved in @var{prep_seq} and the compare\n\
2703 insns are saved in @var{gen_seq}. They will be emitted when all the\n\
2704 compares in the conditional comparision are generated without error.\n\
2705 @var{code} is the @code{rtx_code} of the compare for @var{op0} and @var{op1}.",
2706 rtx, (rtx_insn **prep_seq, rtx_insn **gen_seq, int code, tree op0, tree op1),
2711 "This function prepares to emit a conditional comparison within a sequence\n\
2712 of conditional comparisons. It returns an appropriate comparison with\n\
2713 @code{CC} for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2714 The insns to prepare the compare are saved in @var{prep_seq} and the compare\n\
2715 insns are saved in @var{gen_seq}. They will be emitted when all the\n\
2716 compares in the conditional comparision are generated without error. The\n\
2717 @var{prev} expression is the result of a prior call to @code{gen_ccmp_first}\n\
2718 or @code{gen_ccmp_next}. It may return @code{NULL} if the combination of\n\
2719 @var{prev} and this comparison is not supported, otherwise the result must\n\
2720 be appropriate for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2721 @var{code} is the @code{rtx_code} of the compare for @var{op0} and @var{op1}.\n\
2722 @var{bit_code} is @code{AND} or @code{IOR}, which is the op on the compares.",
2723 rtx, (rtx_insn **prep_seq, rtx_insn **gen_seq, rtx prev, int cmp_code, tree op0, tree op1, int bit_code),
2726 /* Return a new value for loop unroll size. */
2728 (loop_unroll_adjust,
2729 "This target hook returns a new value for the number of times @var{loop}\n\
2730 should be unrolled. The parameter @var{nunroll} is the number of times\n\
2731 the loop is to be unrolled. The parameter @var{loop} is a pointer to\n\
2732 the loop, which is going to be checked for unrolling. This target hook\n\
2733 is required only when the target has special constraints like maximum\n\
2734 number of memory accesses.",
2735 unsigned, (unsigned nunroll, class loop *loop),
2738 /* True if X is a legitimate MODE-mode immediate operand. */
2740 (legitimate_constant_p,
2741 "This hook returns true if @var{x} is a legitimate constant for a\n\
2742 @var{mode}-mode immediate operand on the target machine. You can assume that\n\
2743 @var{x} satisfies @code{CONSTANT_P}, so you need not check this.\n\
2745 The default definition returns true.",
2746 bool, (machine_mode mode, rtx x),
2747 hook_bool_mode_rtx_true)
2749 /* True if X is a TLS operand whose value should be pre-computed. */
2752 "This hook returns true if @var{x} is a TLS operand on the target\n\
2753 machine that should be pre-computed when used as the argument in a call.\n\
2754 You can assume that @var{x} satisfies @code{CONSTANT_P}, so you need not \n\
2757 The default definition returns false.",
2758 bool, (machine_mode mode, rtx x),
2759 hook_bool_mode_rtx_false)
2761 /* True if the constant X cannot be placed in the constant pool. */
2763 (cannot_force_const_mem,
2764 "This hook should return true if @var{x} is of a form that cannot (or\n\
2765 should not) be spilled to the constant pool. @var{mode} is the mode\n\
2768 The default version of this hook returns false.\n\
2770 The primary reason to define this hook is to prevent reload from\n\
2771 deciding that a non-legitimate constant would be better reloaded\n\
2772 from the constant pool instead of spilling and reloading a register\n\
2773 holding the constant. This restriction is often true of addresses\n\
2774 of TLS symbols for various targets.",
2775 bool, (machine_mode mode, rtx x),
2776 hook_bool_mode_rtx_false)
2779 (cannot_copy_insn_p,
2780 "True if the insn @var{x} cannot be duplicated.",
2781 bool, (rtx_insn *), NULL)
2783 /* True if X is considered to be commutative. */
2786 "This target hook returns @code{true} if @var{x} is considered to be commutative.\n\
2787 Usually, this is just COMMUTATIVE_P (@var{x}), but the HP PA doesn't consider\n\
2788 PLUS to be commutative inside a MEM@. @var{outer_code} is the rtx code\n\
2789 of the enclosing rtl, if known, otherwise it is UNKNOWN.",
2790 bool, (const_rtx x, int outer_code),
2791 hook_bool_const_rtx_commutative_p)
2793 /* True if ADDR is an address-expression whose effect depends
2794 on the mode of the memory reference it is used in. */
2796 (mode_dependent_address_p,
2797 "This hook returns @code{true} if memory address @var{addr} in address\n\
2798 space @var{addrspace} can have\n\
2799 different meanings depending on the machine mode of the memory\n\
2800 reference it is used for or if the address is valid for some modes\n\
2803 Autoincrement and autodecrement addresses typically have mode-dependent\n\
2804 effects because the amount of the increment or decrement is the size\n\
2805 of the operand being addressed. Some machines have other mode-dependent\n\
2806 addresses. Many RISC machines have no mode-dependent addresses.\n\
2808 You may assume that @var{addr} is a valid address for the machine.\n\
2810 The default version of this hook returns @code{false}.",
2811 bool, (const_rtx addr, addr_space_t addrspace),
2812 default_mode_dependent_address_p)
2814 /* Given an invalid address X for a given machine mode, try machine-specific
2815 ways to make it legitimate. Return X or an invalid address on failure. */
2817 (legitimize_address,
2818 "This hook is given an invalid memory address @var{x} for an\n\
2819 operand of mode @var{mode} and should try to return a valid memory\n\
2822 @findex break_out_memory_refs\n\
2823 @var{x} will always be the result of a call to @code{break_out_memory_refs},\n\
2824 and @var{oldx} will be the operand that was given to that function to produce\n\
2827 The code of the hook should not alter the substructure of\n\
2828 @var{x}. If it transforms @var{x} into a more legitimate form, it\n\
2829 should return the new @var{x}.\n\
2831 It is not necessary for this hook to come up with a legitimate address,\n\
2832 with the exception of native TLS addresses (@pxref{Emulated TLS}).\n\
2833 The compiler has standard ways of doing so in all cases. In fact, if\n\
2834 the target supports only emulated TLS, it\n\
2835 is safe to omit this hook or make it return @var{x} if it cannot find\n\
2836 a valid way to legitimize the address. But often a machine-dependent\n\
2837 strategy can generate better code.",
2838 rtx, (rtx x, rtx oldx, machine_mode mode),
2839 default_legitimize_address)
2841 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
2843 (delegitimize_address,
2844 "This hook is used to undo the possibly obfuscating effects of the\n\
2845 @code{LEGITIMIZE_ADDRESS} and @code{LEGITIMIZE_RELOAD_ADDRESS} target\n\
2846 macros. Some backend implementations of these macros wrap symbol\n\
2847 references inside an @code{UNSPEC} rtx to represent PIC or similar\n\
2848 addressing modes. This target hook allows GCC's optimizers to understand\n\
2849 the semantics of these opaque @code{UNSPEC}s by converting them back\n\
2850 into their original form.",
2852 delegitimize_mem_from_attrs)
2854 /* Given an RTX, return true if it is not ok to emit it into debug info
2857 (const_not_ok_for_debug_p,
2858 "This hook should return true if @var{x} should not be emitted into\n\
2861 default_const_not_ok_for_debug_p)
2863 /* Given an address RTX, say whether it is valid. */
2865 (legitimate_address_p,
2866 "A function that returns whether @var{x} (an RTX) is a legitimate memory\n\
2867 address on the target machine for a memory operand of mode @var{mode}.\n\
2869 Legitimate addresses are defined in two variants: a strict variant and a\n\
2870 non-strict one. The @var{strict} parameter chooses which variant is\n\
2871 desired by the caller.\n\
2873 The strict variant is used in the reload pass. It must be defined so\n\
2874 that any pseudo-register that has not been allocated a hard register is\n\
2875 considered a memory reference. This is because in contexts where some\n\
2876 kind of register is required, a pseudo-register with no hard register\n\
2877 must be rejected. For non-hard registers, the strict variant should look\n\
2878 up the @code{reg_renumber} array; it should then proceed using the hard\n\
2879 register number in the array, or treat the pseudo as a memory reference\n\
2880 if the array holds @code{-1}.\n\
2882 The non-strict variant is used in other passes. It must be defined to\n\
2883 accept all pseudo-registers in every context where some kind of\n\
2884 register is required.\n\
2886 Normally, constant addresses which are the sum of a @code{symbol_ref}\n\
2887 and an integer are stored inside a @code{const} RTX to mark them as\n\
2888 constant. Therefore, there is no need to recognize such sums\n\
2889 specifically as legitimate addresses. Normally you would simply\n\
2890 recognize any @code{const} as legitimate.\n\
2892 Usually @code{PRINT_OPERAND_ADDRESS} is not prepared to handle constant\n\
2893 sums that are not marked with @code{const}. It assumes that a naked\n\
2894 @code{plus} indicates indexing. If so, then you @emph{must} reject such\n\
2895 naked constant sums as illegitimate addresses, so that none of them will\n\
2896 be given to @code{PRINT_OPERAND_ADDRESS}.\n\
2898 @cindex @code{TARGET_ENCODE_SECTION_INFO} and address validation\n\
2899 On some machines, whether a symbolic address is legitimate depends on\n\
2900 the section that the address refers to. On these machines, define the\n\
2901 target hook @code{TARGET_ENCODE_SECTION_INFO} to store the information\n\
2902 into the @code{symbol_ref}, and then check for it here. When you see a\n\
2903 @code{const}, you will have to look inside it to find the\n\
2904 @code{symbol_ref} in order to determine the section. @xref{Assembler\n\
2907 @cindex @code{GO_IF_LEGITIMATE_ADDRESS}\n\
2908 Some ports are still using a deprecated legacy substitute for\n\
2909 this hook, the @code{GO_IF_LEGITIMATE_ADDRESS} macro. This macro\n\
2913 #define GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label})\n\
2917 and should @code{goto @var{label}} if the address @var{x} is a valid\n\
2918 address on the target machine for a memory operand of mode @var{mode}.\n\
2920 @findex REG_OK_STRICT\n\
2921 Compiler source files that want to use the strict variant of this\n\
2922 macro define the macro @code{REG_OK_STRICT}. You should use an\n\
2923 @code{#ifdef REG_OK_STRICT} conditional to define the strict variant in\n\
2924 that case and the non-strict variant otherwise.\n\
2926 Using the hook is usually simpler because it limits the number of\n\
2927 files that are recompiled when changes are made.",
2928 bool, (machine_mode mode, rtx x, bool strict),
2929 default_legitimate_address_p)
2931 /* True if the given constant can be put into an object_block. */
2933 (use_blocks_for_constant_p,
2934 "This hook should return true if pool entries for constant @var{x} can\n\
2935 be placed in an @code{object_block} structure. @var{mode} is the mode\n\
2938 The default version returns false for all constants.",
2939 bool, (machine_mode mode, const_rtx x),
2940 hook_bool_mode_const_rtx_false)
2942 /* True if the given decl can be put into an object_block. */
2944 (use_blocks_for_decl_p,
2945 "This hook should return true if pool entries for @var{decl} should\n\
2946 be placed in an @code{object_block} structure.\n\
2948 The default version returns true for all decls.",
2949 bool, (const_tree decl),
2950 hook_bool_const_tree_true)
2952 /* The minimum and maximum byte offsets for anchored addresses. */
2955 "The minimum offset that should be applied to a section anchor.\n\
2956 On most targets, it should be the smallest offset that can be\n\
2957 applied to a base register while still giving a legitimate address\n\
2958 for every mode. The default value is 0.",
2963 "Like @code{TARGET_MIN_ANCHOR_OFFSET}, but the maximum (inclusive)\n\
2964 offset that should be applied to section anchors. The default\n\
2968 /* True if section anchors can be used to access the given symbol. */
2970 (use_anchors_for_symbol_p,
2971 "Return true if GCC should attempt to use anchors to access @code{SYMBOL_REF}\n\
2972 @var{x}. You can assume @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})} and\n\
2973 @samp{!SYMBOL_REF_ANCHOR_P (@var{x})}.\n\
2975 The default version is correct for most targets, but you might need to\n\
2976 intercept this hook to handle things like target-specific attributes\n\
2977 or target-specific sections.",
2978 bool, (const_rtx x),
2979 default_use_anchors_for_symbol_p)
2981 /* True if target supports indirect functions. */
2984 "It returns true if the target supports GNU indirect functions.\n\
2985 The support includes the assembler, linker and dynamic linker.\n\
2986 The default value of this hook is based on target's libc.",
2988 default_has_ifunc_p)
2990 /* True if it is OK to do sibling call optimization for the specified
2991 call expression EXP. DECL will be the called function, or NULL if
2992 this is an indirect call. */
2994 (function_ok_for_sibcall,
2995 "True if it is OK to do sibling call optimization for the specified\n\
2996 call expression @var{exp}. @var{decl} will be the called function,\n\
2997 or @code{NULL} if this is an indirect call.\n\
2999 It is not uncommon for limitations of calling conventions to prevent\n\
3000 tail calls to functions outside the current unit of translation, or\n\
3001 during PIC compilation. The hook is used to enforce these restrictions,\n\
3002 as the @code{sibcall} md pattern cannot fail, or fall over to a\n\
3003 ``normal'' call. The criteria for successful sibling call optimization\n\
3004 may vary greatly between different architectures.",
3005 bool, (tree decl, tree exp),
3006 hook_bool_tree_tree_false)
3008 /* Establish appropriate back-end context for processing the function
3009 FNDECL. The argument might be NULL to indicate processing at top
3010 level, outside of any function scope. */
3012 (set_current_function,
3013 "The compiler invokes this hook whenever it changes its current function\n\
3014 context (@code{cfun}). You can define this function if\n\
3015 the back end needs to perform any initialization or reset actions on a\n\
3016 per-function basis. For example, it may be used to implement function\n\
3017 attributes that affect register usage or code generation patterns.\n\
3018 The argument @var{decl} is the declaration for the new function context,\n\
3019 and may be null to indicate that the compiler has left a function context\n\
3020 and is returning to processing at the top level.\n\
3021 The default hook function does nothing.\n\
3023 GCC sets @code{cfun} to a dummy function context during initialization of\n\
3024 some parts of the back end. The hook function is not invoked in this\n\
3025 situation; you need not worry about the hook being invoked recursively,\n\
3026 or when the back end is in a partially-initialized state.\n\
3027 @code{cfun} might be @code{NULL} to indicate processing at top level,\n\
3028 outside of any function scope.",
3029 void, (tree decl), hook_void_tree)
3031 /* True if EXP should be placed in a "small data" section. */
3034 "Returns true if @var{exp} should be placed into a ``small data'' section.\n\
3035 The default version of this hook always returns false.",
3036 bool, (const_tree exp),
3037 hook_bool_const_tree_false)
3039 /* True if EXP names an object for which name resolution must resolve
3040 to the current executable or shared library. */
3043 "Returns true if @var{exp} names an object for which name resolution\n\
3044 rules must resolve to the current ``module'' (dynamic shared library\n\
3045 or executable image).\n\
3047 The default version of this hook implements the name resolution rules\n\
3048 for ELF, which has a looser model of global name binding than other\n\
3049 currently supported object file formats.",
3050 bool, (const_tree exp),
3051 default_binds_local_p)
3053 /* Check if profiling code is before or after prologue. */
3055 (profile_before_prologue,
3056 "It returns true if target wants profile code emitted before prologue.\n\n\
3057 The default version of this hook use the target macro\n\
3058 @code{PROFILE_BEFORE_PROLOGUE}.",
3060 default_profile_before_prologue)
3062 /* Return true if a leaf function should stay leaf even with profiling
3065 (keep_leaf_when_profiled,
3066 "This target hook returns true if the target wants the leaf flag for\
3067 the current function to stay true even if it calls mcount. This might\
3068 make sense for targets using the leaf flag only to determine whether a\
3069 stack frame needs to be generated or not and for which the call to\
3070 mcount is generated before the function prologue.",
3072 default_keep_leaf_when_profiled)
3074 /* Modify and return the identifier of a DECL's external name,
3075 originally identified by ID, as required by the target,
3076 (eg, append @nn to windows32 stdcall function names).
3077 The default is to return ID without modification. */
3079 (mangle_decl_assembler_name,
3080 "Define this hook if you need to postprocess the assembler name generated\n\
3081 by target-independent code. The @var{id} provided to this hook will be\n\
3082 the computed name (e.g., the macro @code{DECL_NAME} of the @var{decl} in C,\n\
3083 or the mangled name of the @var{decl} in C++). The return value of the\n\
3084 hook is an @code{IDENTIFIER_NODE} for the appropriate mangled name on\n\
3085 your target system. The default implementation of this hook just\n\
3086 returns the @var{id} provided.",
3087 tree, (tree decl, tree id),
3088 default_mangle_decl_assembler_name)
3090 /* Do something target-specific to record properties of the DECL into
3091 the associated SYMBOL_REF. */
3093 (encode_section_info,
3094 "Define this hook if references to a symbol or a constant must be\n\
3095 treated differently depending on something about the variable or\n\
3096 function named by the symbol (such as what section it is in).\n\
3098 The hook is executed immediately after rtl has been created for\n\
3099 @var{decl}, which may be a variable or function declaration or\n\
3100 an entry in the constant pool. In either case, @var{rtl} is the\n\
3101 rtl in question. Do @emph{not} use @code{DECL_RTL (@var{decl})}\n\
3102 in this hook; that field may not have been initialized yet.\n\
3104 In the case of a constant, it is safe to assume that the rtl is\n\
3105 a @code{mem} whose address is a @code{symbol_ref}. Most decls\n\
3106 will also have this form, but that is not guaranteed. Global\n\
3107 register variables, for instance, will have a @code{reg} for their\n\
3108 rtl. (Normally the right thing to do with such unusual rtl is\n\
3111 The @var{new_decl_p} argument will be true if this is the first time\n\
3112 that @code{TARGET_ENCODE_SECTION_INFO} has been invoked on this decl. It will\n\
3113 be false for subsequent invocations, which will happen for duplicate\n\
3114 declarations. Whether or not anything must be done for the duplicate\n\
3115 declaration depends on whether the hook examines @code{DECL_ATTRIBUTES}.\n\
3116 @var{new_decl_p} is always true when the hook is called for a constant.\n\
3118 @cindex @code{SYMBOL_REF_FLAG}, in @code{TARGET_ENCODE_SECTION_INFO}\n\
3119 The usual thing for this hook to do is to record flags in the\n\
3120 @code{symbol_ref}, using @code{SYMBOL_REF_FLAG} or @code{SYMBOL_REF_FLAGS}.\n\
3121 Historically, the name string was modified if it was necessary to\n\
3122 encode more than one bit of information, but this practice is now\n\
3123 discouraged; use @code{SYMBOL_REF_FLAGS}.\n\
3125 The default definition of this hook, @code{default_encode_section_info}\n\
3126 in @file{varasm.c}, sets a number of commonly-useful bits in\n\
3127 @code{SYMBOL_REF_FLAGS}. Check whether the default does what you need\n\
3128 before overriding it.",
3129 void, (tree decl, rtx rtl, int new_decl_p),
3130 default_encode_section_info)
3132 /* Undo the effects of encode_section_info on the symbol string. */
3134 (strip_name_encoding,
3135 "Decode @var{name} and return the real name part, sans\n\
3136 the characters that @code{TARGET_ENCODE_SECTION_INFO}\n\
3138 const char *, (const char *name),
3139 default_strip_name_encoding)
3141 /* If shift optabs for MODE are known to always truncate the shift count,
3142 return the mask that they apply. Return 0 otherwise. */
3144 (shift_truncation_mask,
3145 "This function describes how the standard shift patterns for @var{mode}\n\
3146 deal with shifts by negative amounts or by more than the width of the mode.\n\
3147 @xref{shift patterns}.\n\
3149 On many machines, the shift patterns will apply a mask @var{m} to the\n\
3150 shift count, meaning that a fixed-width shift of @var{x} by @var{y} is\n\
3151 equivalent to an arbitrary-width shift of @var{x} by @var{y & m}. If\n\
3152 this is true for mode @var{mode}, the function should return @var{m},\n\
3153 otherwise it should return 0. A return value of 0 indicates that no\n\
3154 particular behavior is guaranteed.\n\
3156 Note that, unlike @code{SHIFT_COUNT_TRUNCATED}, this function does\n\
3157 @emph{not} apply to general shift rtxes; it applies only to instructions\n\
3158 that are generated by the named shift patterns.\n\
3160 The default implementation of this function returns\n\
3161 @code{GET_MODE_BITSIZE (@var{mode}) - 1} if @code{SHIFT_COUNT_TRUNCATED}\n\
3162 and 0 otherwise. This definition is always safe, but if\n\
3163 @code{SHIFT_COUNT_TRUNCATED} is false, and some shift patterns\n\
3164 nevertheless truncate the shift count, you may get better code\n\
3166 unsigned HOST_WIDE_INT, (machine_mode mode),
3167 default_shift_truncation_mask)
3169 /* Return the number of divisions in the given MODE that should be present,
3170 so that it is profitable to turn the division into a multiplication by
3173 (min_divisions_for_recip_mul,
3174 "When @option{-ffast-math} is in effect, GCC tries to optimize\n\
3175 divisions by the same divisor, by turning them into multiplications by\n\
3176 the reciprocal. This target hook specifies the minimum number of divisions\n\
3177 that should be there for GCC to perform the optimization for a variable\n\
3178 of mode @var{mode}. The default implementation returns 3 if the machine\n\
3179 has an instruction for the division, and 2 if it does not.",
3180 unsigned int, (machine_mode mode),
3181 default_min_divisions_for_recip_mul)
3184 (truly_noop_truncation,
3185 "This hook returns true if it is safe to ``convert'' a value of\n\
3186 @var{inprec} bits to one of @var{outprec} bits (where @var{outprec} is\n\
3187 smaller than @var{inprec}) by merely operating on it as if it had only\n\
3188 @var{outprec} bits. The default returns true unconditionally, which\n\
3189 is correct for most machines. When @code{TARGET_TRULY_NOOP_TRUNCATION}\n\
3190 returns false, the machine description should provide a @code{trunc}\n\
3191 optab to specify the RTL that performs the required truncation.\n\
3193 If @code{TARGET_MODES_TIEABLE_P} returns false for a pair of modes,\n\
3194 suboptimal code can result if this hook returns true for the corresponding\n\
3195 mode sizes. Making this hook return false in such cases may improve things.",
3196 bool, (poly_uint64 outprec, poly_uint64 inprec),
3197 hook_bool_puint64_puint64_true)
3199 /* If the representation of integral MODE is such that values are
3200 always sign-extended to a wider mode MODE_REP then return
3201 SIGN_EXTEND. Return UNKNOWN otherwise. */
3202 /* Note that the return type ought to be RTX_CODE, but that's not
3203 necessarily defined at this point. */
3206 "The representation of an integral mode can be such that the values\n\
3207 are always extended to a wider integral mode. Return\n\
3208 @code{SIGN_EXTEND} if values of @var{mode} are represented in\n\
3209 sign-extended form to @var{rep_mode}. Return @code{UNKNOWN}\n\
3210 otherwise. (Currently, none of the targets use zero-extended\n\
3211 representation this way so unlike @code{LOAD_EXTEND_OP},\n\
3212 @code{TARGET_MODE_REP_EXTENDED} is expected to return either\n\
3213 @code{SIGN_EXTEND} or @code{UNKNOWN}. Also no target extends\n\
3214 @var{mode} to @var{rep_mode} so that @var{rep_mode} is not the next\n\
3215 widest integral mode and currently we take advantage of this fact.)\n\
3217 Similarly to @code{LOAD_EXTEND_OP} you may return a non-@code{UNKNOWN}\n\
3218 value even if the extension is not performed on certain hard registers\n\
3219 as long as for the @code{REGNO_REG_CLASS} of these hard registers\n\
3220 @code{TARGET_CAN_CHANGE_MODE_CLASS} returns false.\n\
3222 Note that @code{TARGET_MODE_REP_EXTENDED} and @code{LOAD_EXTEND_OP}\n\
3223 describe two related properties. If you define\n\
3224 @code{TARGET_MODE_REP_EXTENDED (mode, word_mode)} you probably also want\n\
3225 to define @code{LOAD_EXTEND_OP (mode)} to return the same type of\n\
3228 In order to enforce the representation of @code{mode},\n\
3229 @code{TARGET_TRULY_NOOP_TRUNCATION} should return false when truncating to\n\
3231 int, (scalar_int_mode mode, scalar_int_mode rep_mode),
3232 default_mode_rep_extended)
3235 (setjmp_preserves_nonvolatile_regs_p,
3236 "On some targets, it is assumed that the compiler will spill all pseudos\n\
3237 that are live across a call to @code{setjmp}, while other targets treat\n\
3238 @code{setjmp} calls as normal function calls.\n\
3240 This hook returns false if @code{setjmp} calls do not preserve all\n\
3241 non-volatile registers so that gcc that must spill all pseudos that are\n\
3242 live across @code{setjmp} calls. Define this to return true if the\n\
3243 target does not need to spill all pseudos live across @code{setjmp} calls.\n\
3244 The default implementation conservatively assumes all pseudos must be\n\
3245 spilled across @code{setjmp} calls.",
3247 hook_bool_void_false)
3249 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
3251 (valid_pointer_mode,
3252 "Define this to return nonzero if the port can handle pointers\n\
3253 with machine mode @var{mode}. The default version of this\n\
3254 hook returns true for both @code{ptr_mode} and @code{Pmode}.",
3255 bool, (scalar_int_mode mode),
3256 default_valid_pointer_mode)
3258 /* Disambiguate with errno. */
3260 (ref_may_alias_errno,
3261 "Define this to return nonzero if the memory reference @var{ref}\
3262 may alias with the system C library errno location. The default\
3263 version of this hook assumes the system C library errno location\
3264 is either a declaration of type int or accessed by dereferencing\
3266 bool, (ao_ref *ref),
3267 default_ref_may_alias_errno)
3269 /* Support for named address spaces. */
3271 #define HOOK_PREFIX "TARGET_ADDR_SPACE_"
3272 HOOK_VECTOR (TARGET_ADDR_SPACE_HOOKS, addr_space)
3274 /* MODE to use for a pointer into another address space. */
3277 "Define this to return the machine mode to use for pointers to\n\
3278 @var{address_space} if the target supports named address spaces.\n\
3279 The default version of this hook returns @code{ptr_mode}.",
3280 scalar_int_mode, (addr_space_t address_space),
3281 default_addr_space_pointer_mode)
3283 /* MODE to use for an address in another address space. */
3286 "Define this to return the machine mode to use for addresses in\n\
3287 @var{address_space} if the target supports named address spaces.\n\
3288 The default version of this hook returns @code{Pmode}.",
3289 scalar_int_mode, (addr_space_t address_space),
3290 default_addr_space_address_mode)
3292 /* True if MODE is valid for a pointer in __attribute__((mode("MODE")))
3293 in another address space. */
3295 (valid_pointer_mode,
3296 "Define this to return nonzero if the port can handle pointers\n\
3297 with machine mode @var{mode} to address space @var{as}. This target\n\
3298 hook is the same as the @code{TARGET_VALID_POINTER_MODE} target hook,\n\
3299 except that it includes explicit named address space support. The default\n\
3300 version of this hook returns true for the modes returned by either the\n\
3301 @code{TARGET_ADDR_SPACE_POINTER_MODE} or @code{TARGET_ADDR_SPACE_ADDRESS_MODE}\n\
3302 target hooks for the given address space.",
3303 bool, (scalar_int_mode mode, addr_space_t as),
3304 default_addr_space_valid_pointer_mode)
3306 /* True if an address is a valid memory address to a given named address
3307 space for a given mode. */
3309 (legitimate_address_p,
3310 "Define this to return true if @var{exp} is a valid address for mode\n\
3311 @var{mode} in the named address space @var{as}. The @var{strict}\n\
3312 parameter says whether strict addressing is in effect after reload has\n\
3313 finished. This target hook is the same as the\n\
3314 @code{TARGET_LEGITIMATE_ADDRESS_P} target hook, except that it includes\n\
3315 explicit named address space support.",
3316 bool, (machine_mode mode, rtx exp, bool strict, addr_space_t as),
3317 default_addr_space_legitimate_address_p)
3319 /* Return an updated address to convert an invalid pointer to a named
3320 address space to a valid one. If NULL_RTX is returned use machine
3321 independent methods to make the address valid. */
3323 (legitimize_address,
3324 "Define this to modify an invalid address @var{x} to be a valid address\n\
3325 with mode @var{mode} in the named address space @var{as}. This target\n\
3326 hook is the same as the @code{TARGET_LEGITIMIZE_ADDRESS} target hook,\n\
3327 except that it includes explicit named address space support.",
3328 rtx, (rtx x, rtx oldx, machine_mode mode, addr_space_t as),
3329 default_addr_space_legitimize_address)
3331 /* True if one named address space is a subset of another named address. */
3334 "Define this to return whether the @var{subset} named address space is\n\
3335 contained within the @var{superset} named address space. Pointers to\n\
3336 a named address space that is a subset of another named address space\n\
3337 will be converted automatically without a cast if used together in\n\
3338 arithmetic operations. Pointers to a superset address space can be\n\
3339 converted to pointers to a subset address space via explicit casts.",
3340 bool, (addr_space_t subset, addr_space_t superset),
3341 default_addr_space_subset_p)
3343 /* True if 0 is a valid address in the address space, or false if
3344 0 is a NULL in the address space. */
3346 (zero_address_valid,
3347 "Define this to modify the default handling of address 0 for the\n\
3348 address space. Return true if 0 should be considered a valid address.",
3349 bool, (addr_space_t as),
3350 default_addr_space_zero_address_valid)
3352 /* Function to convert an rtl expression from one address space to another. */
3355 "Define this to convert the pointer expression represented by the RTL\n\
3356 @var{op} with type @var{from_type} that points to a named address\n\
3357 space to a new pointer expression with type @var{to_type} that points\n\
3358 to a different named address space. When this hook it called, it is\n\
3359 guaranteed that one of the two address spaces is a subset of the other,\n\
3360 as determined by the @code{TARGET_ADDR_SPACE_SUBSET_P} target hook.",
3361 rtx, (rtx op, tree from_type, tree to_type),
3362 default_addr_space_convert)
3364 /* Function to encode an address space into dwarf. */
3367 "Define this to define how the address space is encoded in dwarf.\n\
3368 The result is the value to be used with @code{DW_AT_address_class}.",
3369 int, (addr_space_t as),
3370 default_addr_space_debug)
3372 /* Function to emit custom diagnostic if an address space is used. */
3375 "Define this hook if the availability of an address space depends on\n\
3376 command line options and some diagnostics should be printed when the\n\
3377 address space is used. This hook is called during parsing and allows\n\
3378 to emit a better diagnostic compared to the case where the address space\n\
3379 was not registered with @code{c_register_addr_space}. @var{as} is\n\
3380 the address space as registered with @code{c_register_addr_space}.\n\
3381 @var{loc} is the location of the address space qualifier token.\n\
3382 The default implementation does nothing.",
3383 void, (addr_space_t as, location_t loc),
3384 default_addr_space_diagnose_usage)
3386 HOOK_VECTOR_END (addr_space)
3389 #define HOOK_PREFIX "TARGET_"
3392 (lower_local_decl_alignment,
3393 "Define this hook to lower alignment of local, parm or result\n\
3394 decl @samp{(@var{decl})}.",
3399 (static_rtx_alignment,
3400 "This hook returns the preferred alignment in bits for a\n\
3401 statically-allocated rtx, such as a constant pool entry. @var{mode}\n\
3402 is the mode of the rtx. The default implementation returns\n\
3403 @samp{GET_MODE_ALIGNMENT (@var{mode})}.",
3404 HOST_WIDE_INT, (machine_mode mode),
3405 default_static_rtx_alignment)
3408 (constant_alignment,
3409 "This hook returns the alignment in bits of a constant that is being\n\
3410 placed in memory. @var{constant} is the constant and @var{basic_align}\n\
3411 is the alignment that the object would ordinarily have.\n\
3413 The default definition just returns @var{basic_align}.\n\
3415 The typical use of this hook is to increase alignment for string\n\
3416 constants to be word aligned so that @code{strcpy} calls that copy\n\
3417 constants can be done inline. The function\n\
3418 @code{constant_alignment_word_strings} provides such a definition.",
3419 HOST_WIDE_INT, (const_tree constant, HOST_WIDE_INT basic_align),
3420 default_constant_alignment)
3423 (translate_mode_attribute,
3424 "Define this hook if during mode attribute processing, the port should\n\
3425 translate machine_mode @var{mode} to another mode. For example, rs6000's\n\
3426 @code{KFmode}, when it is the same as @code{TFmode}.\n\
3428 The default version of the hook returns that mode that was passed in.",
3429 machine_mode, (machine_mode mode),
3430 default_translate_mode_attribute)
3432 /* True if MODE is valid for the target. By "valid", we mean able to
3433 be manipulated in non-trivial ways. In particular, this means all
3434 the arithmetic is supported. */
3436 (scalar_mode_supported_p,
3437 "Define this to return nonzero if the port is prepared to handle\n\
3438 insns involving scalar mode @var{mode}. For a scalar mode to be\n\
3439 considered supported, all the basic arithmetic and comparisons\n\
3442 The default version of this hook returns true for any mode\n\
3443 required to handle the basic C types (as defined by the port).\n\
3444 Included here are the double-word arithmetic supported by the\n\
3445 code in @file{optabs.c}.",
3446 bool, (scalar_mode mode),
3447 default_scalar_mode_supported_p)
3449 /* Similarly for vector modes. "Supported" here is less strict. At
3450 least some operations are supported; need to check optabs or builtins
3451 for further details. */
3453 (vector_mode_supported_p,
3454 "Define this to return nonzero if the port is prepared to handle\n\
3455 insns involving vector mode @var{mode}. At the very least, it\n\
3456 must have move patterns for this mode.",
3457 bool, (machine_mode mode),
3458 hook_bool_mode_false)
3461 (compatible_vector_types_p,
3462 "Return true if there is no target-specific reason for treating\n\
3463 vector types @var{type1} and @var{type2} as distinct types. The caller\n\
3464 has already checked for target-independent reasons, meaning that the\n\
3465 types are known to have the same mode, to have the same number of elements,\n\
3466 and to have what the caller considers to be compatible element types.\n\
3468 The main reason for defining this hook is to reject pairs of types\n\
3469 that are handled differently by the target's calling convention.\n\
3470 For example, when a new @var{N}-bit vector architecture is added\n\
3471 to a target, the target may want to handle normal @var{N}-bit\n\
3472 @code{VECTOR_TYPE} arguments and return values in the same way as\n\
3473 before, to maintain backwards compatibility. However, it may also\n\
3474 provide new, architecture-specific @code{VECTOR_TYPE}s that are passed\n\
3475 and returned in a more efficient way. It is then important to maintain\n\
3476 a distinction between the ``normal'' @code{VECTOR_TYPE}s and the new\n\
3477 architecture-specific ones.\n\
3479 The default implementation returns true, which is correct for most targets.",
3480 bool, (const_tree type1, const_tree type2),
3481 hook_bool_const_tree_const_tree_true)
3485 "This hook can be used to define the alignment for a vector of type\n\
3486 @var{type}, in order to comply with a platform ABI. The default is to\n\
3487 require natural alignment for vector types. The alignment returned by\n\
3488 this hook must be a power-of-two multiple of the default alignment of\n\
3489 the vector element type.",
3490 HOST_WIDE_INT, (const_tree type),
3491 default_vector_alignment)
3495 "Return the mode that GCC should use for an array that has\n\
3496 @var{nelems} elements, with each element having mode @var{mode}.\n\
3497 Return no mode if the target has no special requirements. In the\n\
3498 latter case, GCC looks for an integer mode of the appropriate size\n\
3499 if available and uses BLKmode otherwise. Usually the search for the\n\
3500 integer mode is limited to @code{MAX_FIXED_MODE_SIZE}, but the\n\
3501 @code{TARGET_ARRAY_MODE_SUPPORTED_P} hook allows a larger mode to be\n\
3502 used in specific cases.\n\
3504 The main use of this hook is to specify that an array of vectors should\n\
3505 also have a vector mode. The default implementation returns no mode.",
3506 opt_machine_mode, (machine_mode mode, unsigned HOST_WIDE_INT nelems),
3507 hook_optmode_mode_uhwi_none)
3509 /* True if we should try to use a scalar mode to represent an array,
3510 overriding the usual MAX_FIXED_MODE limit. */
3512 (array_mode_supported_p,
3513 "Return true if GCC should try to use a scalar mode to store an array\n\
3514 of @var{nelems} elements, given that each element has mode @var{mode}.\n\
3515 Returning true here overrides the usual @code{MAX_FIXED_MODE} limit\n\
3516 and allows GCC to use any defined integer mode.\n\
3518 One use of this hook is to support vector load and store operations\n\
3519 that operate on several homogeneous vectors. For example, ARM NEON\n\
3520 has operations like:\n\
3523 int8x8x3_t vld3_s8 (const int8_t *)\n\
3524 @end smallexample\n\
3526 where the return type is defined as:\n\
3529 typedef struct int8x8x3_t\n\
3533 @end smallexample\n\
3535 If this hook allows @code{val} to have a scalar mode, then\n\
3536 @code{int8x8x3_t} can have the same mode. GCC can then store\n\
3537 @code{int8x8x3_t}s in registers rather than forcing them onto the stack.",
3538 bool, (machine_mode mode, unsigned HOST_WIDE_INT nelems),
3539 hook_bool_mode_uhwi_false)
3542 (libgcc_floating_mode_supported_p,
3543 "Define this to return nonzero if libgcc provides support for the \n\
3544 floating-point mode @var{mode}, which is known to pass \n\
3545 @code{TARGET_SCALAR_MODE_SUPPORTED_P}. The default version of this \n\
3546 hook returns true for all of @code{SFmode}, @code{DFmode}, \n\
3547 @code{XFmode} and @code{TFmode}, if such modes exist.",
3548 bool, (scalar_float_mode mode),
3549 default_libgcc_floating_mode_supported_p)
3553 "Define this to return the machine mode to use for the type \n\
3554 @code{_Float@var{n}}, if @var{extended} is false, or the type \n\
3555 @code{_Float@var{n}x}, if @var{extended} is true. If such a type is not\n\
3556 supported, return @code{opt_scalar_float_mode ()}. The default version of\n\
3557 this hook returns @code{SFmode} for @code{_Float32}, @code{DFmode} for\n\
3558 @code{_Float64} and @code{_Float32x} and @code{TFmode} for \n\
3559 @code{_Float128}, if those modes exist and satisfy the requirements for \n\
3560 those types and pass @code{TARGET_SCALAR_MODE_SUPPORTED_P} and \n\
3561 @code{TARGET_LIBGCC_FLOATING_MODE_SUPPORTED_P}; for @code{_Float64x}, it \n\
3562 returns the first of @code{XFmode} and @code{TFmode} that exists and \n\
3563 satisfies the same requirements; for other types, it returns \n\
3564 @code{opt_scalar_float_mode ()}. The hook is only called for values\n\
3565 of @var{n} and @var{extended} that are valid according to\n\
3566 ISO/IEC TS 18661-3:2015; that is, @var{n} is one of 32, 64, 128, or,\n\
3567 if @var{extended} is false, 16 or greater than 128 and a multiple of 32.",
3568 opt_scalar_float_mode, (int n, bool extended),
3569 default_floatn_mode)
3573 "Define this to return true if the @code{_Float@var{n}} and\n\
3574 @code{_Float@var{n}x} built-in functions should implicitly enable the\n\
3575 built-in function without the @code{__builtin_} prefix in addition to the\n\
3576 normal built-in function with the @code{__builtin_} prefix. The default is\n\
3577 to only enable built-in functions without the @code{__builtin_} prefix for\n\
3578 the GNU C langauge. In strict ANSI/ISO mode, the built-in function without\n\
3579 the @code{__builtin_} prefix is not enabled. The argument @code{FUNC} is the\n\
3580 @code{enum built_in_function} id of the function to be enabled.",
3582 default_floatn_builtin_p)
3584 /* Compute cost of moving data from a register of class FROM to one of
3587 (register_move_cost,
3588 "This target hook should return the cost of moving data of mode @var{mode}\n\
3589 from a register in class @var{from} to one in class @var{to}. The classes\n\
3590 are expressed using the enumeration values such as @code{GENERAL_REGS}.\n\
3591 A value of 2 is the default; other values are interpreted relative to\n\
3594 It is not required that the cost always equal 2 when @var{from} is the\n\
3595 same as @var{to}; on some machines it is expensive to move between\n\
3596 registers if they are not general registers.\n\
3598 If reload sees an insn consisting of a single @code{set} between two\n\
3599 hard registers, and if @code{TARGET_REGISTER_MOVE_COST} applied to their\n\
3600 classes returns a value of 2, reload does not check to ensure that the\n\
3601 constraints of the insn are met. Setting a cost of other than 2 will\n\
3602 allow reload to verify that the constraints are met. You should do this\n\
3603 if the @samp{mov@var{m}} pattern's constraints do not allow such copying.\n\
3605 The default version of this function returns 2.",
3606 int, (machine_mode mode, reg_class_t from, reg_class_t to),
3607 default_register_move_cost)
3609 /* Compute cost of moving registers to/from memory. */
3610 /* ??? Documenting the argument types for this hook requires a GFDL
3611 license grant. Also, the documentation uses a different name for RCLASS. */
3614 "This target hook should return the cost of moving data of mode @var{mode}\n\
3615 between a register of class @var{rclass} and memory; @var{in} is @code{false}\n\
3616 if the value is to be written to memory, @code{true} if it is to be read in.\n\
3617 This cost is relative to those in @code{TARGET_REGISTER_MOVE_COST}.\n\
3618 If moving between registers and memory is more expensive than between two\n\
3619 registers, you should add this target hook to express the relative cost.\n\
3621 If you do not add this target hook, GCC uses a default cost of 4 plus\n\
3622 the cost of copying via a secondary reload register, if one is\n\
3623 needed. If your machine requires a secondary reload register to copy\n\
3624 between memory and a register of @var{rclass} but the reload mechanism is\n\
3625 more complex than copying via an intermediate, use this target hook to\n\
3626 reflect the actual cost of the move.\n\
3628 GCC defines the function @code{memory_move_secondary_cost} if\n\
3629 secondary reloads are needed. It computes the costs due to copying via\n\
3630 a secondary register. If your machine copies from memory using a\n\
3631 secondary register in the conventional way but the default base value of\n\
3632 4 is not correct for your machine, use this target hook to add some other\n\
3633 value to the result of that function. The arguments to that function\n\
3634 are the same as to this target hook.",
3635 int, (machine_mode mode, reg_class_t rclass, bool in),
3636 default_memory_move_cost)
3639 (use_by_pieces_infrastructure_p,
3640 "GCC will attempt several strategies when asked to copy between\n\
3641 two areas of memory, or to set, clear or store to memory, for example\n\
3642 when copying a @code{struct}. The @code{by_pieces} infrastructure\n\
3643 implements such memory operations as a sequence of load, store or move\n\
3644 insns. Alternate strategies are to expand the\n\
3645 @code{cpymem} or @code{setmem} optabs, to emit a library call, or to emit\n\
3646 unit-by-unit, loop-based operations.\n\
3648 This target hook should return true if, for a memory operation with a\n\
3649 given @var{size} and @var{alignment}, using the @code{by_pieces}\n\
3650 infrastructure is expected to result in better code generation.\n\
3651 Both @var{size} and @var{alignment} are measured in terms of storage\n\
3654 The parameter @var{op} is one of: @code{CLEAR_BY_PIECES},\n\
3655 @code{MOVE_BY_PIECES}, @code{SET_BY_PIECES}, @code{STORE_BY_PIECES} or\n\
3656 @code{COMPARE_BY_PIECES}. These describe the type of memory operation\n\
3657 under consideration.\n\
3659 The parameter @var{speed_p} is true if the code is currently being\n\
3660 optimized for speed rather than size.\n\
3662 Returning true for higher values of @var{size} can improve code generation\n\
3663 for speed if the target does not provide an implementation of the\n\
3664 @code{cpymem} or @code{setmem} standard names, if the @code{cpymem} or\n\
3665 @code{setmem} implementation would be more expensive than a sequence of\n\
3666 insns, or if the overhead of a library call would dominate that of\n\
3667 the body of the memory operation.\n\
3669 Returning true for higher values of @code{size} may also cause an increase\n\
3670 in code size, for example where the number of insns emitted to perform a\n\
3671 move would be greater than that of a library call.",
3672 bool, (unsigned HOST_WIDE_INT size, unsigned int alignment,
3673 enum by_pieces_operation op, bool speed_p),
3674 default_use_by_pieces_infrastructure_p)
3677 (overlap_op_by_pieces_p,
3678 "This target hook should return true if when the @code{by_pieces}\n\
3679 infrastructure is used, an offset adjusted unaligned memory operation\n\
3680 in the smallest integer mode for the last piece operation of a memory\n\
3681 region can be generated to avoid doing more than one smaller operations.",
3683 hook_bool_void_false)
3686 (compare_by_pieces_branch_ratio,
3687 "When expanding a block comparison in MODE, gcc can try to reduce the\n\
3688 number of branches at the expense of more memory operations. This hook\n\
3689 allows the target to override the default choice. It should return the\n\
3690 factor by which branches should be reduced over the plain expansion with\n\
3691 one comparison per @var{mode}-sized piece. A port can also prevent a\n\
3692 particular mode from being used for block comparisons by returning a\n\
3693 negative number from this hook.",
3694 int, (machine_mode mode),
3695 default_compare_by_pieces_branch_ratio)
3698 (slow_unaligned_access,
3699 "This hook returns true if memory accesses described by the\n\
3700 @var{mode} and @var{alignment} parameters have a cost many times greater\n\
3701 than aligned accesses, for example if they are emulated in a trap handler.\n\
3702 This hook is invoked only for unaligned accesses, i.e.@: when\n\
3703 @code{@var{alignment} < GET_MODE_ALIGNMENT (@var{mode})}.\n\
3705 When this hook returns true, the compiler will act as if\n\
3706 @code{STRICT_ALIGNMENT} were true when generating code for block\n\
3707 moves. This can cause significantly more instructions to be produced.\n\
3708 Therefore, do not make this hook return true if unaligned accesses only\n\
3709 add a cycle or two to the time for a memory access.\n\
3711 The hook must return true whenever @code{STRICT_ALIGNMENT} is true.\n\
3712 The default implementation returns @code{STRICT_ALIGNMENT}.",
3713 bool, (machine_mode mode, unsigned int align),
3714 default_slow_unaligned_access)
3718 "Return true if the optimizers should use optab @var{op} with\n\
3719 modes @var{mode1} and @var{mode2} for optimization type @var{opt_type}.\n\
3720 The optab is known to have an associated @file{.md} instruction\n\
3721 whose C condition is true. @var{mode2} is only meaningful for conversion\n\
3722 optabs; for direct optabs it is a copy of @var{mode1}.\n\
3724 For example, when called with @var{op} equal to @code{rint_optab} and\n\
3725 @var{mode1} equal to @code{DFmode}, the hook should say whether the\n\
3726 optimizers should use optab @code{rintdf2}.\n\
3728 The default hook returns true for all inputs.",
3729 bool, (int op, machine_mode mode1, machine_mode mode2,
3730 optimization_type opt_type),
3731 default_optab_supported_p)
3733 /* True for MODE if the target expects that registers in this mode will
3734 be allocated to registers in a small register class. The compiler is
3735 allowed to use registers explicitly used in the rtl as spill registers
3736 but it should prevent extending the lifetime of these registers. */
3738 (small_register_classes_for_mode_p,
3739 "Define this to return nonzero for machine modes for which the port has\n\
3740 small register classes. If this target hook returns nonzero for a given\n\
3741 @var{mode}, the compiler will try to minimize the lifetime of registers\n\
3742 in @var{mode}. The hook may be called with @code{VOIDmode} as argument.\n\
3743 In this case, the hook is expected to return nonzero if it returns nonzero\n\
3746 On some machines, it is risky to let hard registers live across arbitrary\n\
3747 insns. Typically, these machines have instructions that require values\n\
3748 to be in specific registers (like an accumulator), and reload will fail\n\
3749 if the required hard register is used for another purpose across such an\n\
3752 Passes before reload do not know which hard registers will be used\n\
3753 in an instruction, but the machine modes of the registers set or used in\n\
3754 the instruction are already known. And for some machines, register\n\
3755 classes are small for, say, integer registers but not for floating point\n\
3756 registers. For example, the AMD x86-64 architecture requires specific\n\
3757 registers for the legacy x86 integer instructions, but there are many\n\
3758 SSE registers for floating point operations. On such targets, a good\n\
3759 strategy may be to return nonzero from this hook for @code{INTEGRAL_MODE_P}\n\
3760 machine modes but zero for the SSE register classes.\n\
3762 The default version of this hook returns false for any mode. It is always\n\
3763 safe to redefine this hook to return with a nonzero value. But if you\n\
3764 unnecessarily define it, you will reduce the amount of optimizations\n\
3765 that can be performed in some cases. If you do not define this hook\n\
3766 to return a nonzero value when it is required, the compiler will run out\n\
3767 of spill registers and print a fatal error message.",
3768 bool, (machine_mode mode),
3769 hook_bool_mode_false)
3771 /* Register number for a flags register. Only needs to be defined if the
3772 target is constrainted to use post-reload comparison elimination. */
3775 "If the target has a dedicated flags register, and it needs to use the\n\
3776 post-reload comparison elimination pass, or the delay slot filler pass,\n\
3777 then this value should be set appropriately.",
3778 unsigned int, INVALID_REGNUM)
3780 /* Compute a (partial) cost for rtx X. Return true if the complete
3781 cost has been computed, and false if subexpressions should be
3782 scanned. In either case, *TOTAL contains the cost result. */
3783 /* Note that OUTER_CODE ought to be RTX_CODE, but that's
3784 not necessarily defined at this point. */
3787 "This target hook describes the relative costs of RTL expressions.\n\
3789 The cost may depend on the precise form of the expression, which is\n\
3790 available for examination in @var{x}, and the fact that @var{x} appears\n\
3791 as operand @var{opno} of an expression with rtx code @var{outer_code}.\n\
3792 That is, the hook can assume that there is some rtx @var{y} such\n\
3793 that @samp{GET_CODE (@var{y}) == @var{outer_code}} and such that\n\
3794 either (a) @samp{XEXP (@var{y}, @var{opno}) == @var{x}} or\n\
3795 (b) @samp{XVEC (@var{y}, @var{opno})} contains @var{x}.\n\
3797 @var{mode} is @var{x}'s machine mode, or for cases like @code{const_int} that\n\
3798 do not have a mode, the mode in which @var{x} is used.\n\
3800 In implementing this hook, you can use the construct\n\
3801 @code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3804 On entry to the hook, @code{*@var{total}} contains a default estimate\n\
3805 for the cost of the expression. The hook should modify this value as\n\
3806 necessary. Traditionally, the default costs are @code{COSTS_N_INSNS (5)}\n\
3807 for multiplications, @code{COSTS_N_INSNS (7)} for division and modulus\n\
3808 operations, and @code{COSTS_N_INSNS (1)} for all other operations.\n\
3810 When optimizing for code size, i.e.@: when @code{speed} is\n\
3811 false, this target hook should be used to estimate the relative\n\
3812 size cost of an expression, again relative to @code{COSTS_N_INSNS}.\n\
3814 The hook returns true when all subexpressions of @var{x} have been\n\
3815 processed, and false when @code{rtx_cost} should recurse.",
3816 bool, (rtx x, machine_mode mode, int outer_code, int opno, int *total, bool speed),
3817 hook_bool_rtx_mode_int_int_intp_bool_false)
3819 /* Compute the cost of X, used as an address. Never called with
3820 invalid addresses. */
3823 "This hook computes the cost of an addressing mode that contains\n\
3824 @var{address}. If not defined, the cost is computed from\n\
3825 the @var{address} expression and the @code{TARGET_RTX_COST} hook.\n\
3827 For most CISC machines, the default cost is a good approximation of the\n\
3828 true cost of the addressing mode. However, on RISC machines, all\n\
3829 instructions normally have the same length and execution time. Hence\n\
3830 all addresses will have equal costs.\n\
3832 In cases where more than one form of an address is known, the form with\n\
3833 the lowest cost will be used. If multiple forms have the same, lowest,\n\
3834 cost, the one that is the most complex will be used.\n\
3836 For example, suppose an address that is equal to the sum of a register\n\
3837 and a constant is used twice in the same basic block. When this macro\n\
3838 is not defined, the address will be computed in a register and memory\n\
3839 references will be indirect through that register. On machines where\n\
3840 the cost of the addressing mode containing the sum is no higher than\n\
3841 that of a simple indirect reference, this will produce an additional\n\
3842 instruction and possibly require an additional register. Proper\n\
3843 specification of this macro eliminates this overhead for such machines.\n\
3845 This hook is never called with an invalid address.\n\
3847 On machines where an address involving more than one register is as\n\
3848 cheap as an address computation involving only one register, defining\n\
3849 @code{TARGET_ADDRESS_COST} to reflect this can cause two registers to\n\
3850 be live over a region of code where only one would have been if\n\
3851 @code{TARGET_ADDRESS_COST} were not defined in that manner. This effect\n\
3852 should be considered in the definition of this macro. Equivalent costs\n\
3853 should probably only be given to addresses with different numbers of\n\
3854 registers on machines with lots of registers.",
3855 int, (rtx address, machine_mode mode, addr_space_t as, bool speed),
3856 default_address_cost)
3858 /* Compute a cost for INSN. */
3861 "This target hook describes the relative costs of RTL instructions.\n\
3863 In implementing this hook, you can use the construct\n\
3864 @code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3867 When optimizing for code size, i.e.@: when @code{speed} is\n\
3868 false, this target hook should be used to estimate the relative\n\
3869 size cost of an expression, again relative to @code{COSTS_N_INSNS}.",
3870 int, (rtx_insn *insn, bool speed), NULL)
3872 /* Give a cost, in RTX Costs units, for an edge. Like BRANCH_COST, but with
3873 well defined units. */
3875 (max_noce_ifcvt_seq_cost,
3876 "This hook returns a value in the same units as @code{TARGET_RTX_COSTS},\n\
3877 giving the maximum acceptable cost for a sequence generated by the RTL\n\
3878 if-conversion pass when conditional execution is not available.\n\
3879 The RTL if-conversion pass attempts to convert conditional operations\n\
3880 that would require a branch to a series of unconditional operations and\n\
3881 @code{mov@var{mode}cc} insns. This hook returns the maximum cost of the\n\
3882 unconditional instructions and the @code{mov@var{mode}cc} insns.\n\
3883 RTL if-conversion is cancelled if the cost of the converted sequence\n\
3884 is greater than the value returned by this hook.\n\
3886 @code{e} is the edge between the basic block containing the conditional\n\
3887 branch to the basic block which would be executed if the condition\n\
3890 The default implementation of this hook uses the\n\
3891 @code{max-rtl-if-conversion-[un]predictable} parameters if they are set,\n\
3892 and uses a multiple of @code{BRANCH_COST} otherwise.",
3893 unsigned int, (edge e),
3894 default_max_noce_ifcvt_seq_cost)
3896 /* Return true if the given instruction sequence is a good candidate
3897 as a replacement for the if-convertible sequence. */
3899 (noce_conversion_profitable_p,
3900 "This hook returns true if the instruction sequence @code{seq} is a good\n\
3901 candidate as a replacement for the if-convertible sequence described in\n\
3903 bool, (rtx_insn *seq, struct noce_if_info *if_info),
3904 default_noce_conversion_profitable_p)
3906 /* Return true if new_addr should be preferred over the existing address used by
3909 (new_address_profitable_p,
3910 "Return @code{true} if it is profitable to replace the address in\n\
3911 @var{memref} with @var{new_addr}. This allows targets to prevent the\n\
3912 scheduler from undoing address optimizations. The instruction containing the\n\
3913 memref is @var{insn}. The default implementation returns @code{true}.",
3914 bool, (rtx memref, rtx_insn * insn, rtx new_addr),
3915 default_new_address_profitable_p)
3918 (estimated_poly_value,
3919 "Return an estimate of the runtime value of @var{val}, for use in\n\
3920 things like cost calculations or profiling frequencies. @var{kind} is used\n\
3921 to ask for the minimum, maximum, and likely estimates of the value through\n\
3922 the @code{POLY_VALUE_MIN}, @code{POLY_VALUE_MAX} and\n\
3923 @code{POLY_VALUE_LIKELY} values. The default\n\
3924 implementation returns the lowest possible value of @var{val}.",
3925 HOST_WIDE_INT, (poly_int64 val, poly_value_estimate_kind kind),
3926 default_estimated_poly_value)
3928 /* Permit speculative instructions in delay slots during delayed-branch
3931 (no_speculation_in_delay_slots_p,
3932 "This predicate controls the use of the eager delay slot filler to disallow\n\
3933 speculatively executed instructions being placed in delay slots. Targets\n\
3934 such as certain MIPS architectures possess both branches with and without\n\
3935 delay slots. As the eager delay slot filler can decrease performance,\n\
3936 disabling it is beneficial when ordinary branches are available. Use of\n\
3937 delay slot branches filled using the basic filler is often still desirable\n\
3938 as the delay slot can hide a pipeline bubble.", bool, (void),
3939 hook_bool_void_false)
3941 /* Return where to allocate pseudo for a given hard register initial value. */
3943 (allocate_initial_value,
3945 When the initial value of a hard register has been copied in a pseudo\n\
3946 register, it is often not necessary to actually allocate another register\n\
3947 to this pseudo register, because the original hard register or a stack slot\n\
3948 it has been saved into can be used. @code{TARGET_ALLOCATE_INITIAL_VALUE}\n\
3949 is called at the start of register allocation once for each hard register\n\
3950 that had its initial value copied by using\n\
3951 @code{get_func_hard_reg_initial_val} or @code{get_hard_reg_initial_val}.\n\
3952 Possible values are @code{NULL_RTX}, if you don't want\n\
3953 to do any special allocation, a @code{REG} rtx---that would typically be\n\
3954 the hard register itself, if it is known not to be clobbered---or a\n\
3956 If you are returning a @code{MEM}, this is only a hint for the allocator;\n\
3957 it might decide to use another register anyways.\n\
3958 You may use @code{current_function_is_leaf} or \n\
3959 @code{REG_N_SETS} in the hook to determine if the hard\n\
3960 register in question will not be clobbered.\n\
3961 The default value of this hook is @code{NULL}, which disables any special\n\
3963 rtx, (rtx hard_reg), NULL)
3965 /* Return nonzero if evaluating UNSPEC X might cause a trap.
3966 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */
3969 "This target hook returns nonzero if @var{x}, an @code{unspec} or\n\
3970 @code{unspec_volatile} operation, might cause a trap. Targets can use\n\
3971 this hook to enhance precision of analysis for @code{unspec} and\n\
3972 @code{unspec_volatile} operations. You may call @code{may_trap_p_1}\n\
3973 to analyze inner elements of @var{x} in which case @var{flags} should be\n\
3975 int, (const_rtx x, unsigned flags),
3976 default_unspec_may_trap_p)
3978 /* Given a register, this hook should return a parallel of registers
3979 to represent where to find the register pieces. Define this hook
3980 if the register and its mode are represented in Dwarf in
3981 non-contiguous locations, or if the register should be
3982 represented in more than one register in Dwarf. Otherwise, this
3983 hook should return NULL_RTX. */
3985 (dwarf_register_span,
3986 "Given a register, this hook should return a parallel of registers to\n\
3987 represent where to find the register pieces. Define this hook if the\n\
3988 register and its mode are represented in Dwarf in non-contiguous\n\
3989 locations, or if the register should be represented in more than one\n\
3990 register in Dwarf. Otherwise, this hook should return @code{NULL_RTX}.\n\
3991 If not defined, the default is to return @code{NULL_RTX}.",
3995 /* Given a register return the mode of the corresponding DWARF frame
3998 (dwarf_frame_reg_mode,
3999 "Given a register, this hook should return the mode which the\n\
4000 corresponding Dwarf frame register should have. This is normally\n\
4001 used to return a smaller mode than the raw mode to prevent call\n\
4002 clobbered parts of a register altering the frame register size",
4003 machine_mode, (int regno),
4004 default_dwarf_frame_reg_mode)
4006 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
4007 entries not corresponding directly to registers below
4008 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
4009 code, given the address of the table. */
4011 (init_dwarf_reg_sizes_extra,
4012 "If some registers are represented in Dwarf-2 unwind information in\n\
4013 multiple pieces, define this hook to fill in information about the\n\
4014 sizes of those pieces in the table used by the unwinder at runtime.\n\
4015 It will be called by @code{expand_builtin_init_dwarf_reg_sizes} after\n\
4016 filling in a single size corresponding to each hard register;\n\
4017 @var{address} is the address of the table.",
4018 void, (tree address),
4021 /* Fetch the fixed register(s) which hold condition codes, for
4022 targets where it makes sense to look for duplicate assignments to
4023 the condition codes. This should return true if there is such a
4024 register, false otherwise. The arguments should be set to the
4025 fixed register numbers. Up to two condition code registers are
4026 supported. If there is only one for this target, the int pointed
4027 at by the second argument should be set to -1. */
4029 (fixed_condition_code_regs,
4030 "On targets which use a hard\n\
4031 register rather than a pseudo-register to hold condition codes, the\n\
4032 regular CSE passes are often not able to identify cases in which the\n\
4033 hard register is set to a common value. Use this hook to enable a\n\
4034 small pass which optimizes such cases. This hook should return true\n\
4035 to enable this pass, and it should set the integers to which its\n\
4036 arguments point to the hard register numbers used for condition codes.\n\
4037 When there is only one such register, as is true on most systems, the\n\
4038 integer pointed to by @var{p2} should be set to\n\
4039 @code{INVALID_REGNUM}.\n\
4041 The default version of this hook returns false.",
4042 bool, (unsigned int *p1, unsigned int *p2),
4043 hook_bool_uintp_uintp_false)
4045 /* If two condition code modes are compatible, return a condition
4046 code mode which is compatible with both, such that a comparison
4047 done in the returned mode will work for both of the original
4048 modes. If the condition code modes are not compatible, return
4051 (cc_modes_compatible,
4052 "On targets which use multiple condition code modes in class\n\
4053 @code{MODE_CC}, it is sometimes the case that a comparison can be\n\
4054 validly done in more than one mode. On such a system, define this\n\
4055 target hook to take two mode arguments and to return a mode in which\n\
4056 both comparisons may be validly done. If there is no such mode,\n\
4057 return @code{VOIDmode}.\n\
4059 The default version of this hook checks whether the modes are the\n\
4060 same. If they are, it returns that mode. If they are different, it\n\
4061 returns @code{VOIDmode}.",
4062 machine_mode, (machine_mode m1, machine_mode m2),
4063 default_cc_modes_compatible)
4065 /* Do machine-dependent code transformations. Called just before
4066 delayed-branch scheduling. */
4068 (machine_dependent_reorg,
4069 "If non-null, this hook performs a target-specific pass over the\n\
4070 instruction stream. The compiler will run it at all optimization levels,\n\
4071 just before the point at which it normally does delayed-branch scheduling.\n\
4073 The exact purpose of the hook varies from target to target. Some use\n\
4074 it to do transformations that are necessary for correctness, such as\n\
4075 laying out in-function constant pools or avoiding hardware hazards.\n\
4076 Others use it as an opportunity to do some machine-dependent optimizations.\n\
4078 You need not implement the hook if it has nothing to do. The default\n\
4079 definition is null.",
4082 /* Create the __builtin_va_list type. */
4084 (build_builtin_va_list,
4085 "This hook returns a type node for @code{va_list} for the target.\n\
4086 The default version of the hook returns @code{void*}.",
4088 std_build_builtin_va_list)
4090 /* Enumerate the va list variants. */
4093 "This target hook is used in function @code{c_common_nodes_and_builtins}\n\
4094 to iterate through the target specific builtin types for va_list. The\n\
4095 variable @var{idx} is used as iterator. @var{pname} has to be a pointer\n\
4096 to a @code{const char *} and @var{ptree} a pointer to a @code{tree} typed\n\
4098 The arguments @var{pname} and @var{ptree} are used to store the result of\n\
4099 this macro and are set to the name of the va_list builtin type and its\n\
4101 If the return value of this macro is zero, then there is no more element.\n\
4102 Otherwise the @var{IDX} should be increased for the next call of this\n\
4103 macro to iterate through all types.",
4104 int, (int idx, const char **pname, tree *ptree),
4107 /* Get the cfun/fndecl calling abi __builtin_va_list type. */
4110 "This hook returns the va_list type of the calling convention specified by\n\
4112 The default version of this hook returns @code{va_list_type_node}.",
4113 tree, (tree fndecl),
4116 /* Get the __builtin_va_list type dependent on input type. */
4118 (canonical_va_list_type,
4119 "This hook returns the va_list type of the calling convention specified by the\n\
4120 type of @var{type}. If @var{type} is not a valid va_list type, it returns\n\
4123 std_canonical_va_list_type)
4125 /* ??? Documenting this hook requires a GFDL license grant. */
4127 (expand_builtin_va_start,
4128 "Expand the @code{__builtin_va_start} builtin.",
4129 void, (tree valist, rtx nextarg), NULL)
4131 /* Gimplifies a VA_ARG_EXPR. */
4133 (gimplify_va_arg_expr,
4134 "This hook performs target-specific gimplification of\n\
4135 @code{VA_ARG_EXPR}. The first two parameters correspond to the\n\
4136 arguments to @code{va_arg}; the latter two are as in\n\
4137 @code{gimplify.c:gimplify_expr}.",
4138 tree, (tree valist, tree type, gimple_seq *pre_p, gimple_seq *post_p),
4139 std_gimplify_va_arg_expr)
4141 /* Validity-checking routines for PCH files, target-specific.
4142 get_pch_validity returns a pointer to the data to be stored,
4143 and stores the size in its argument. pch_valid_p gets the same
4144 information back and returns NULL if the PCH is valid,
4145 or an error message if not. */
4148 "This hook returns a pointer to the data needed by\n\
4149 @code{TARGET_PCH_VALID_P} and sets\n\
4150 @samp{*@var{sz}} to the size of the data in bytes.",
4151 void *, (size_t *sz),
4152 default_get_pch_validity)
4156 "This hook checks whether the options used to create a PCH file are\n\
4157 compatible with the current settings. It returns @code{NULL}\n\
4158 if so and a suitable error message if not. Error messages will\n\
4159 be presented to the user and must be localized using @samp{_(@var{msg})}.\n\
4161 @var{data} is the data that was returned by @code{TARGET_GET_PCH_VALIDITY}\n\
4162 when the PCH file was created and @var{sz} is the size of that data in bytes.\n\
4163 It's safe to assume that the data was created by the same version of the\n\
4164 compiler, so no format checking is needed.\n\
4166 The default definition of @code{default_pch_valid_p} should be\n\
4167 suitable for most targets.",
4168 const char *, (const void *data, size_t sz),
4169 default_pch_valid_p)
4173 "Called before writing out a PCH file. If the target has some\n\
4174 garbage-collected data that needs to be in a particular state on PCH loads,\n\
4175 it can use this hook to enforce that state. Very few targets need\n\
4176 to do anything here.",
4180 /* If nonnull, this function checks whether a PCH file with the
4181 given set of target flags can be used. It returns NULL if so,
4182 otherwise it returns an error message. */
4184 (check_pch_target_flags,
4185 "If this hook is nonnull, the default implementation of\n\
4186 @code{TARGET_PCH_VALID_P} will use it to check for compatible values\n\
4187 of @code{target_flags}. @var{pch_flags} specifies the value that\n\
4188 @code{target_flags} had when the PCH file was created. The return\n\
4189 value is the same as for @code{TARGET_PCH_VALID_P}.",
4190 const char *, (int pch_flags), NULL)
4192 /* True if the compiler should give an enum type only as many
4193 bytes as it takes to represent the range of possible values of
4196 (default_short_enums,
4197 "This target hook should return true if the compiler should give an\n\
4198 @code{enum} type only as many bytes as it takes to represent the range\n\
4199 of possible values of that type. It should return false if all\n\
4200 @code{enum} types should be allocated like @code{int}.\n\
4202 The default is to return false.",
4204 hook_bool_void_false)
4206 /* This target hook returns an rtx that is used to store the address
4207 of the current frame into the built-in setjmp buffer. */
4209 (builtin_setjmp_frame_value,
4210 "This target hook should return an rtx that is used to store\n\
4211 the address of the current frame into the built in @code{setjmp} buffer.\n\
4212 The default value, @code{virtual_stack_vars_rtx}, is correct for most\n\
4213 machines. One reason you may need to define this target hook is if\n\
4214 @code{hard_frame_pointer_rtx} is the appropriate value on your machine.",
4216 default_builtin_setjmp_frame_value)
4218 /* This target hook should manipulate the outputs, inputs, constraints,
4219 and clobbers the port wishes for pre-processing the asm. */
4222 "This target hook may add @dfn{clobbers} to @var{clobbers} and\n\
4223 @var{clobbered_regs} for any hard regs the port wishes to automatically\n\
4224 clobber for an asm. The @var{outputs} and @var{inputs} may be inspected\n\
4225 to avoid clobbering a register that is already used by the asm.\n\
4227 It may modify the @var{outputs}, @var{inputs}, @var{input_modes}, and\n\
4228 @var{constraints} as necessary for other pre-processing. In this case the\n\
4229 return value is a sequence of insns to emit after the asm. Note that\n\
4230 changes to @var{inputs} must be accompanied by the corresponding changes\n\
4231 to @var{input_modes}.",
4233 (vec<rtx>& outputs, vec<rtx>& inputs, vec<machine_mode>& input_modes,
4234 vec<const char *>& constraints, vec<rtx>& clobbers,
4235 HARD_REG_SET& clobbered_regs),
4238 /* This target hook allows the backend to specify a calling convention
4239 in the debug information. This function actually returns an
4240 enum dwarf_calling_convention, but because of forward declarations
4241 and not wanting to include dwarf2.h everywhere target.h is included
4242 the function is being declared as an int. */
4244 (dwarf_calling_convention,
4245 "Define this to enable the dwarf attribute @code{DW_AT_calling_convention} to\n\
4246 be emitted for each function. Instead of an integer return the enum\n\
4247 value for the @code{DW_CC_} tag.",
4248 int, (const_tree function),
4249 hook_int_const_tree_0)
4251 /* This target hook allows the backend to emit frame-related insns that
4252 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
4253 engine will invoke it on insns of the form
4254 (set (reg) (unspec [...] UNSPEC_INDEX))
4256 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
4257 to let the backend emit the call frame instructions. */
4259 (dwarf_handle_frame_unspec,
4260 "This target hook allows the backend to emit frame-related insns that\n\
4261 contain UNSPECs or UNSPEC_VOLATILEs. The DWARF 2 call frame debugging\n\
4262 info engine will invoke it on insns of the form\n\
4264 (set (reg) (unspec [@dots{}] UNSPEC_INDEX))\n\
4265 @end smallexample\n\
4268 (set (reg) (unspec_volatile [@dots{}] UNSPECV_INDEX)).\n\
4269 @end smallexample\n\
4270 to let the backend emit the call frame instructions. @var{label} is\n\
4271 the CFI label attached to the insn, @var{pattern} is the pattern of\n\
4272 the insn and @var{index} is @code{UNSPEC_INDEX} or @code{UNSPECV_INDEX}.",
4273 void, (const char *label, rtx pattern, int index), NULL)
4276 (dwarf_poly_indeterminate_value,
4277 "Express the value of @code{poly_int} indeterminate @var{i} as a DWARF\n\
4278 expression, with @var{i} counting from 1. Return the number of a DWARF\n\
4279 register @var{R} and set @samp{*@var{factor}} and @samp{*@var{offset}} such\n\
4280 that the value of the indeterminate is:\n\
4282 value_of(@var{R}) / @var{factor} - @var{offset}\n\
4283 @end smallexample\n\
4285 A target only needs to define this hook if it sets\n\
4286 @samp{NUM_POLY_INT_COEFFS} to a value greater than 1.",
4287 unsigned int, (unsigned int i, unsigned int *factor, int *offset),
4288 default_dwarf_poly_indeterminate_value)
4290 /* ??? Documenting this hook requires a GFDL license grant. */
4292 (stdarg_optimize_hook,
4293 "Perform architecture specific checking of statements gimplified\
4294 from @code{VA_ARG_EXPR}. @var{stmt} is the statement. Returns true if\
4295 the statement doesn't need to be checked for @code{va_list} references.",
4296 bool, (struct stdarg_info *ai, const gimple *stmt), NULL)
4298 /* This target hook allows the operating system to override the DECL
4299 that represents the external variable that contains the stack
4300 protection guard variable. The type of this DECL is ptr_type_node. */
4302 (stack_protect_guard,
4303 "This hook returns a @code{DECL} node for the external variable to use\n\
4304 for the stack protection guard. This variable is initialized by the\n\
4305 runtime to some random value and is used to initialize the guard value\n\
4306 that is placed at the top of the local stack frame. The type of this\n\
4307 variable must be @code{ptr_type_node}.\n\
4309 The default version of this hook creates a variable called\n\
4310 @samp{__stack_chk_guard}, which is normally defined in @file{libgcc2.c}.",
4312 default_stack_protect_guard)
4314 /* This target hook allows the operating system to override the CALL_EXPR
4315 that is invoked when a check vs the guard variable fails. */
4317 (stack_protect_fail,
4318 "This hook returns a @code{CALL_EXPR} that alerts the runtime that the\n\
4319 stack protect guard variable has been modified. This expression should\n\
4320 involve a call to a @code{noreturn} function.\n\
4322 The default version of this hook invokes a function called\n\
4323 @samp{__stack_chk_fail}, taking no arguments. This function is\n\
4324 normally defined in @file{libgcc2.c}.",
4326 default_external_stack_protect_fail)
4328 /* This target hook allows the operating system to disable the default stack
4329 protector runtime support. */
4331 (stack_protect_runtime_enabled_p,
4332 "Returns true if the target wants GCC's default stack protect runtime support,\
4333 otherwise return false. The default implementation always returns true.",
4335 hook_bool_void_true)
4338 (have_speculation_safe_value,
4339 "This hook is used to determine the level of target support for\n\
4340 @code{__builtin_speculation_safe_value}. If called with an argument\n\
4341 of false, it returns true if the target has been modified to support\n\
4342 this builtin. If called with an argument of true, it returns true\n\
4343 if the target requires active mitigation execution might be speculative.\n\
4345 The default implementation returns false if the target does not define\n\
4346 a pattern named @code{speculation_barrier}. Else it returns true\n\
4347 for the first case and whether the pattern is enabled for the current\n\
4348 compilation for the second case.\n\
4350 For targets that have no processors that can execute instructions\n\
4351 speculatively an alternative implemenation of this hook is available:\n\
4352 simply redefine this hook to @code{speculation_safe_value_not_needed}\n\
4353 along with your other target hooks.",
4354 bool, (bool active), default_have_speculation_safe_value)
4357 (speculation_safe_value,
4358 "This target hook can be used to generate a target-specific code\n\
4359 sequence that implements the @code{__builtin_speculation_safe_value}\n\
4360 built-in function. The function must always return @var{val} in\n\
4361 @var{result} in mode @var{mode} when the cpu is not executing\n\
4362 speculatively, but must never return that when speculating until it\n\
4363 is known that the speculation will not be unwound. The hook supports\n\
4364 two primary mechanisms for implementing the requirements. The first\n\
4365 is to emit a speculation barrier which forces the processor to wait\n\
4366 until all prior speculative operations have been resolved; the second\n\
4367 is to use a target-specific mechanism that can track the speculation\n\
4368 state and to return @var{failval} if it can determine that\n\
4369 speculation must be unwound at a later time.\n\
4371 The default implementation simply copies @var{val} to @var{result} and\n\
4372 emits a @code{speculation_barrier} instruction if that is defined.",
4373 rtx, (machine_mode mode, rtx result, rtx val, rtx failval),
4374 default_speculation_safe_value)
4378 "Return true if we can predict it is possible to use a low-overhead loop\n\
4379 for a particular loop. The parameter @var{loop} is a pointer to the loop.\n\
4380 This target hook is required only when the target supports low-overhead\n\
4381 loops, and will help ivopts to make some decisions.\n\
4382 The default version of this hook returns false.",
4383 bool, (class loop *loop),
4384 default_predict_doloop_p)
4387 (have_count_reg_decr_p,
4388 "Return true if the target supports hardware count register for decrement\n\
4390 The default value is false.",
4394 (doloop_cost_for_generic,
4395 "One IV candidate dedicated for doloop is introduced in IVOPTs, we can\n\
4396 calculate the computation cost of adopting it to any generic IV use by\n\
4397 function get_computation_cost as before. But for targets which have\n\
4398 hardware count register support for decrement and branch, it may have to\n\
4399 move IV value from hardware count register to general purpose register\n\
4400 while doloop IV candidate is used for generic IV uses. It probably takes\n\
4401 expensive penalty. This hook allows target owners to define the cost for\n\
4402 this especially for generic IV uses.\n\
4403 The default value is zero.",
4407 (doloop_cost_for_address,
4408 "One IV candidate dedicated for doloop is introduced in IVOPTs, we can\n\
4409 calculate the computation cost of adopting it to any address IV use by\n\
4410 function get_computation_cost as before. But for targets which have\n\
4411 hardware count register support for decrement and branch, it may have to\n\
4412 move IV value from hardware count register to general purpose register\n\
4413 while doloop IV candidate is used for address IV uses. It probably takes\n\
4414 expensive penalty. This hook allows target owners to define the cost for\n\
4415 this escpecially for address IV uses.\n\
4416 The default value is zero.",
4421 "Return true if it is possible to use low-overhead loops (@code{doloop_end}\n\
4422 and @code{doloop_begin}) for a particular loop. @var{iterations} gives the\n\
4423 exact number of iterations, or 0 if not known. @var{iterations_max} gives\n\
4424 the maximum number of iterations, or 0 if not known. @var{loop_depth} is\n\
4425 the nesting depth of the loop, with 1 for innermost loops, 2 for loops that\n\
4426 contain innermost loops, and so on. @var{entered_at_top} is true if the\n\
4427 loop is only entered from the top.\n\
4429 This hook is only used if @code{doloop_end} is available. The default\n\
4430 implementation returns true. You can use @code{can_use_doloop_if_innermost}\n\
4431 if the loop must be the innermost, and if there are no other restrictions.",
4432 bool, (const widest_int &iterations, const widest_int &iterations_max,
4433 unsigned int loop_depth, bool entered_at_top),
4434 hook_bool_wint_wint_uint_bool_true)
4436 /* Returns NULL if target supports the insn within a doloop block,
4437 otherwise it returns an error message. */
4439 (invalid_within_doloop,
4441 Take an instruction in @var{insn} and return NULL if it is valid within a\n\
4442 low-overhead loop, otherwise return a string explaining why doloop\n\
4443 could not be applied.\n\
4445 Many targets use special registers for low-overhead looping. For any\n\
4446 instruction that clobbers these this function should return a string indicating\n\
4447 the reason why the doloop could not be applied.\n\
4448 By default, the RTL loop optimizer does not use a present doloop pattern for\n\
4449 loops containing function calls or branch on table instructions.",
4450 const char *, (const rtx_insn *insn),
4451 default_invalid_within_doloop)
4453 /* Returns true for a legitimate combined insn. */
4455 (legitimate_combined_insn,
4456 "Take an instruction in @var{insn} and return @code{false} if the instruction\
4457 is not appropriate as a combination of two or more instructions. The\
4458 default is to accept all instructions.",
4459 bool, (rtx_insn *insn),
4460 hook_bool_rtx_insn_true)
4463 (valid_dllimport_attribute_p,
4464 "@var{decl} is a variable or function with @code{__attribute__((dllimport))}\
4465 specified. Use this hook if the target needs to add extra validation\
4466 checks to @code{handle_dll_attribute}.",
4467 bool, (const_tree decl),
4468 hook_bool_const_tree_true)
4470 /* If non-zero, align constant anchors in CSE to a multiple of this
4474 "On some architectures it can take multiple instructions to synthesize\n\
4475 a constant. If there is another constant already in a register that\n\
4476 is close enough in value then it is preferable that the new constant\n\
4477 is computed from this register using immediate addition or\n\
4478 subtraction. We accomplish this through CSE. Besides the value of\n\
4479 the constant we also add a lower and an upper constant anchor to the\n\
4480 available expressions. These are then queried when encountering new\n\
4481 constants. The anchors are computed by rounding the constant up and\n\
4482 down to a multiple of the value of @code{TARGET_CONST_ANCHOR}.\n\
4483 @code{TARGET_CONST_ANCHOR} should be the maximum positive value\n\
4484 accepted by immediate-add plus one. We currently assume that the\n\
4485 value of @code{TARGET_CONST_ANCHOR} is a power of 2. For example, on\n\
4486 MIPS, where add-immediate takes a 16-bit signed value,\n\
4487 @code{TARGET_CONST_ANCHOR} is set to @samp{0x8000}. The default value\n\
4488 is zero, which disables this optimization.",
4489 unsigned HOST_WIDE_INT, 0)
4491 /* Defines, which target-dependent bits (upper 16) are used by port */
4494 "Validate target specific memory model mask bits. When NULL no target specific\n\
4495 memory model bits are allowed.",
4496 unsigned HOST_WIDE_INT, (unsigned HOST_WIDE_INT val), NULL)
4498 /* Defines an offset bitwise ored into shifted address to get corresponding
4499 Address Sanitizer shadow address, or -1 if Address Sanitizer is not
4500 supported by the target. */
4502 (asan_shadow_offset,
4503 "Return the offset bitwise ored into shifted address to get corresponding\n\
4504 Address Sanitizer shadow memory address. NULL if Address Sanitizer is not\n\
4505 supported by the target. May return 0 if Address Sanitizer is not supported\n\
4507 unsigned HOST_WIDE_INT, (void),
4510 /* Functions relating to calls - argument passing, returns, etc. */
4511 /* Members of struct call have no special macro prefix. */
4512 HOOK_VECTOR (TARGET_CALLS, calls)
4515 (promote_function_mode,
4516 "Like @code{PROMOTE_MODE}, but it is applied to outgoing function arguments or\n\
4517 function return values. The target hook should return the new mode\n\
4518 and possibly change @code{*@var{punsignedp}} if the promotion should\n\
4519 change signedness. This function is called only for scalar @emph{or\n\
4522 @var{for_return} allows to distinguish the promotion of arguments and\n\
4523 return values. If it is @code{1}, a return value is being promoted and\n\
4524 @code{TARGET_FUNCTION_VALUE} must perform the same promotions done here.\n\
4525 If it is @code{2}, the returned mode should be that of the register in\n\
4526 which an incoming parameter is copied, or the outgoing result is computed;\n\
4527 then the hook should return the same mode as @code{promote_mode}, though\n\
4528 the signedness may be different.\n\
4530 @var{type} can be NULL when promoting function arguments of libcalls.\n\
4532 The default is to not promote arguments and return values. You can\n\
4533 also define the hook to @code{default_promote_function_mode_always_promote}\n\
4534 if you would like to apply the same rules given by @code{PROMOTE_MODE}.",
4535 machine_mode, (const_tree type, machine_mode mode, int *punsignedp,
4536 const_tree funtype, int for_return),
4537 default_promote_function_mode)
4540 (promote_prototypes,
4541 "This target hook returns @code{true} if an argument declared in a\n\
4542 prototype as an integral type smaller than @code{int} should actually be\n\
4543 passed as an @code{int}. In addition to avoiding errors in certain\n\
4544 cases of mismatch, it also makes for better code on certain machines.\n\
4545 The default is to not promote prototypes.",
4546 bool, (const_tree fntype),
4547 hook_bool_const_tree_false)
4551 "This target hook should return the location of the structure value\n\
4552 address (normally a @code{mem} or @code{reg}), or 0 if the address is\n\
4553 passed as an ``invisible'' first argument. Note that @var{fndecl} may\n\
4554 be @code{NULL}, for libcalls. You do not need to define this target\n\
4555 hook if the address is always passed as an ``invisible'' first\n\
4558 On some architectures the place where the structure value address\n\
4559 is found by the called function is not the same place that the\n\
4560 caller put it. This can be due to register windows, or it could\n\
4561 be because the function prologue moves it to a different place.\n\
4562 @var{incoming} is @code{1} or @code{2} when the location is needed in\n\
4563 the context of the called function, and @code{0} in the context of\n\
4566 If @var{incoming} is nonzero and the address is to be found on the\n\
4567 stack, return a @code{mem} which refers to the frame pointer. If\n\
4568 @var{incoming} is @code{2}, the result is being used to fetch the\n\
4569 structure value address at the beginning of a function. If you need\n\
4570 to emit adjusting code, you should do it at this point.",
4571 rtx, (tree fndecl, int incoming),
4572 hook_rtx_tree_int_null)
4575 (omit_struct_return_reg,
4576 "Normally, when a function returns a structure by memory, the address\n\
4577 is passed as an invisible pointer argument, but the compiler also\n\
4578 arranges to return the address from the function like it would a normal\n\
4579 pointer return value. Define this to true if that behavior is\n\
4580 undesirable on your target.",
4585 "This target hook should return a nonzero value to say to return the\n\
4586 function value in memory, just as large structures are always returned.\n\
4587 Here @var{type} will be the data type of the value, and @var{fntype}\n\
4588 will be the type of the function doing the returning, or @code{NULL} for\n\
4591 Note that values of mode @code{BLKmode} must be explicitly handled\n\
4592 by this function. Also, the option @option{-fpcc-struct-return}\n\
4593 takes effect regardless of this macro. On most systems, it is\n\
4594 possible to leave the hook undefined; this causes a default\n\
4595 definition to be used, whose value is the constant 1 for @code{BLKmode}\n\
4596 values, and 0 otherwise.\n\
4598 Do not use this hook to indicate that structures and unions should always\n\
4599 be returned in memory. You should instead use @code{DEFAULT_PCC_STRUCT_RETURN}\n\
4601 bool, (const_tree type, const_tree fntype),
4602 default_return_in_memory)
4606 "This hook should return true if values of type @var{type} are returned\n\
4607 at the most significant end of a register (in other words, if they are\n\
4608 padded at the least significant end). You can assume that @var{type}\n\
4609 is returned in a register; the caller is required to check this.\n\
4611 Note that the register provided by @code{TARGET_FUNCTION_VALUE} must\n\
4612 be able to hold the complete return value. For example, if a 1-, 2-\n\
4613 or 3-byte structure is returned at the most significant end of a\n\
4614 4-byte register, @code{TARGET_FUNCTION_VALUE} should provide an\n\
4615 @code{SImode} rtx.",
4616 bool, (const_tree type),
4617 hook_bool_const_tree_false)
4619 /* Return true if a parameter must be passed by reference. TYPE may
4620 be null if this is a libcall. CA may be null if this query is
4621 from __builtin_va_arg. */
4624 "This target hook should return @code{true} if argument @var{arg} at the\n\
4625 position indicated by @var{cum} should be passed by reference. This\n\
4626 predicate is queried after target independent reasons for being\n\
4627 passed by reference, such as @code{TREE_ADDRESSABLE (@var{arg}.type)}.\n\
4629 If the hook returns true, a copy of that argument is made in memory and a\n\
4630 pointer to the argument is passed instead of the argument itself.\n\
4631 The pointer is passed in whatever way is appropriate for passing a pointer\n\
4634 (cumulative_args_t cum, const function_arg_info &arg),
4635 hook_bool_CUMULATIVE_ARGS_arg_info_false)
4638 (expand_builtin_saveregs,
4639 "If defined, this hook produces the machine-specific code for a call to\n\
4640 @code{__builtin_saveregs}. This code will be moved to the very\n\
4641 beginning of the function, before any parameter access are made. The\n\
4642 return value of this function should be an RTX that contains the value\n\
4643 to use as the return of @code{__builtin_saveregs}.",
4645 default_expand_builtin_saveregs)
4647 /* Returns pretend_argument_size. */
4649 (setup_incoming_varargs,
4650 "This target hook offers an alternative to using\n\
4651 @code{__builtin_saveregs} and defining the hook\n\
4652 @code{TARGET_EXPAND_BUILTIN_SAVEREGS}. Use it to store the anonymous\n\
4653 register arguments into the stack so that all the arguments appear to\n\
4654 have been passed consecutively on the stack. Once this is done, you can\n\
4655 use the standard implementation of varargs that works for machines that\n\
4656 pass all their arguments on the stack.\n\
4658 The argument @var{args_so_far} points to the @code{CUMULATIVE_ARGS} data\n\
4659 structure, containing the values that are obtained after processing the\n\
4660 named arguments. The argument @var{arg} describes the last of these named\n\
4663 The target hook should do two things: first, push onto the stack all the\n\
4664 argument registers @emph{not} used for the named arguments, and second,\n\
4665 store the size of the data thus pushed into the @code{int}-valued\n\
4666 variable pointed to by @var{pretend_args_size}. The value that you\n\
4667 store here will serve as additional offset for setting up the stack\n\
4670 Because you must generate code to push the anonymous arguments at\n\
4671 compile time without knowing their data types,\n\
4672 @code{TARGET_SETUP_INCOMING_VARARGS} is only useful on machines that\n\
4673 have just a single category of argument register and use it uniformly\n\
4674 for all data types.\n\
4676 If the argument @var{second_time} is nonzero, it means that the\n\
4677 arguments of the function are being analyzed for the second time. This\n\
4678 happens for an inline function, which is not actually compiled until the\n\
4679 end of the source file. The hook @code{TARGET_SETUP_INCOMING_VARARGS} should\n\
4680 not generate any instructions in this case.",
4681 void, (cumulative_args_t args_so_far, const function_arg_info &arg,
4682 int *pretend_args_size, int second_time),
4683 default_setup_incoming_varargs)
4686 (load_bounds_for_arg,
4687 "This hook is used by expand pass to emit insn to load bounds of\n\
4688 @var{arg} passed in @var{slot}. Expand pass uses this hook in case\n\
4689 bounds of @var{arg} are not passed in register. If @var{slot} is a\n\
4690 memory, then bounds are loaded as for regular pointer loaded from\n\
4691 memory. If @var{slot} is not a memory then @var{slot_no} is an integer\n\
4692 constant holding number of the target dependent special slot which\n\
4693 should be used to obtain bounds. Hook returns RTX holding loaded bounds.",
4694 rtx, (rtx slot, rtx arg, rtx slot_no),
4695 default_load_bounds_for_arg)
4698 (store_bounds_for_arg,
4699 "This hook is used by expand pass to emit insns to store @var{bounds} of\n\
4700 @var{arg} passed in @var{slot}. Expand pass uses this hook in case\n\
4701 @var{bounds} of @var{arg} are not passed in register. If @var{slot} is a\n\
4702 memory, then @var{bounds} are stored as for regular pointer stored in\n\
4703 memory. If @var{slot} is not a memory then @var{slot_no} is an integer\n\
4704 constant holding number of the target dependent special slot which\n\
4705 should be used to store @var{bounds}.",
4706 void, (rtx arg, rtx slot, rtx bounds, rtx slot_no),
4707 default_store_bounds_for_arg)
4710 (load_returned_bounds,
4711 "This hook is used by expand pass to emit insn to load bounds\n\
4712 returned by function call in @var{slot}. Hook returns RTX holding\n\
4715 default_load_returned_bounds)
4718 (store_returned_bounds,
4719 "This hook is used by expand pass to emit insn to store @var{bounds}\n\
4720 returned by function call into @var{slot}.",
4721 void, (rtx slot, rtx bounds),
4722 default_store_returned_bounds)
4726 "While generating RTL for a function call, this target hook is invoked once\n\
4727 for each argument passed to the function, either a register returned by\n\
4728 @code{TARGET_FUNCTION_ARG} or a memory location. It is called just\n\
4729 before the point where argument registers are stored. The type of the\n\
4730 function to be called is also passed as the second argument; it is\n\
4731 @code{NULL_TREE} for libcalls. The @code{TARGET_END_CALL_ARGS} hook is\n\
4732 invoked just after the code to copy the return reg has been emitted.\n\
4733 This functionality can be used to perform special setup of call argument\n\
4734 registers if a target needs it.\n\
4735 For functions without arguments, the hook is called once with @code{pc_rtx}\n\
4736 passed instead of an argument register.\n\
4737 Most ports do not need to implement anything for this hook.",
4743 "This target hook is invoked while generating RTL for a function call,\n\
4744 just after the point where the return reg is copied into a pseudo. It\n\
4745 signals that all the call argument and return registers for the just\n\
4746 emitted call are now no longer in use.\n\
4747 Most ports do not need to implement anything for this hook.",
4752 (strict_argument_naming,
4753 "Define this hook to return @code{true} if the location where a function\n\
4754 argument is passed depends on whether or not it is a named argument.\n\
4756 This hook controls how the @var{named} argument to @code{TARGET_FUNCTION_ARG}\n\
4757 is set for varargs and stdarg functions. If this hook returns\n\
4758 @code{true}, the @var{named} argument is always true for named\n\
4759 arguments, and false for unnamed arguments. If it returns @code{false},\n\
4760 but @code{TARGET_PRETEND_OUTGOING_VARARGS_NAMED} returns @code{true},\n\
4761 then all arguments are treated as named. Otherwise, all named arguments\n\
4762 except the last are treated as named.\n\
4764 You need not define this hook if it always returns @code{false}.",
4765 bool, (cumulative_args_t ca),
4766 hook_bool_CUMULATIVE_ARGS_false)
4768 /* Returns true if we should use
4769 targetm.calls.setup_incoming_varargs() and/or
4770 targetm.calls.strict_argument_naming(). */
4772 (pretend_outgoing_varargs_named,
4773 "If you need to conditionally change ABIs so that one works with\n\
4774 @code{TARGET_SETUP_INCOMING_VARARGS}, but the other works like neither\n\
4775 @code{TARGET_SETUP_INCOMING_VARARGS} nor @code{TARGET_STRICT_ARGUMENT_NAMING} was\n\
4776 defined, then define this hook to return @code{true} if\n\
4777 @code{TARGET_SETUP_INCOMING_VARARGS} is used, @code{false} otherwise.\n\
4778 Otherwise, you should not define this hook.",
4779 bool, (cumulative_args_t ca),
4780 default_pretend_outgoing_varargs_named)
4782 /* Given a complex type T, return true if a parameter of type T
4783 should be passed as two scalars. */
4786 "This hook should return true if parameter of type @var{type} are passed\n\
4787 as two scalar parameters. By default, GCC will attempt to pack complex\n\
4788 arguments into the target's word size. Some ABIs require complex arguments\n\
4789 to be split and treated as their individual components. For example, on\n\
4790 AIX64, complex floats should be passed in a pair of floating point\n\
4791 registers, even though a complex float would fit in one 64-bit floating\n\
4794 The default value of this hook is @code{NULL}, which is treated as always\n\
4796 bool, (const_tree type), NULL)
4798 /* Return true if type T, mode MODE, may not be passed in registers,
4799 but must be passed on the stack. */
4800 /* ??? This predicate should be applied strictly after pass-by-reference.
4801 Need audit to verify that this is the case. */
4803 (must_pass_in_stack,
4804 "This target hook should return @code{true} if we should not pass @var{arg}\n\
4805 solely in registers. The file @file{expr.h} defines a\n\
4806 definition that is usually appropriate, refer to @file{expr.h} for additional\n\
4808 bool, (const function_arg_info &arg),
4809 must_pass_in_stack_var_size_or_pad)
4811 /* Return true if type TYPE, mode MODE, which is passed by reference,
4812 should have the object copy generated by the callee rather than
4813 the caller. It is never called for TYPE requiring constructors. */
4816 "The function argument described by the parameters to this hook is\n\
4817 known to be passed by reference. The hook should return true if the\n\
4818 function argument should be copied by the callee instead of copied\n\
4821 For any argument for which the hook returns true, if it can be\n\
4822 determined that the argument is not modified, then a copy need\n\
4823 not be generated.\n\
4825 The default version of this hook always returns false.",
4827 (cumulative_args_t cum, const function_arg_info &arg),
4828 hook_bool_CUMULATIVE_ARGS_arg_info_false)
4830 /* Return zero for arguments passed entirely on the stack or entirely
4831 in registers. If passed in both, return the number of bytes passed
4832 in registers; the balance is therefore passed on the stack. */
4835 "This target hook returns the number of bytes at the beginning of an\n\
4836 argument that must be put in registers. The value must be zero for\n\
4837 arguments that are passed entirely in registers or that are entirely\n\
4838 pushed on the stack.\n\
4840 On some machines, certain arguments must be passed partially in\n\
4841 registers and partially in memory. On these machines, typically the\n\
4842 first few words of arguments are passed in registers, and the rest\n\
4843 on the stack. If a multi-word argument (a @code{double} or a\n\
4844 structure) crosses that boundary, its first few words must be passed\n\
4845 in registers and the rest must be pushed. This macro tells the\n\
4846 compiler when this occurs, and how many bytes should go in registers.\n\
4848 @code{TARGET_FUNCTION_ARG} for these arguments should return the first\n\
4849 register to be used by the caller for this argument; likewise\n\
4850 @code{TARGET_FUNCTION_INCOMING_ARG}, for the called function.",
4851 int, (cumulative_args_t cum, const function_arg_info &arg),
4852 hook_int_CUMULATIVE_ARGS_arg_info_0)
4854 /* Update the state in CA to advance past an argument in the
4855 argument list. The values MODE, TYPE, and NAMED describe that
4858 (function_arg_advance,
4859 "This hook updates the summarizer variable pointed to by @var{ca} to\n\
4860 advance past argument @var{arg} in the argument list. Once this is done,\n\
4861 the variable @var{cum} is suitable for analyzing the @emph{following}\n\
4862 argument with @code{TARGET_FUNCTION_ARG}, etc.\n\
4864 This hook need not do anything if the argument in question was passed\n\
4865 on the stack. The compiler knows how to track the amount of stack space\n\
4866 used for arguments without any special help.",
4868 (cumulative_args_t ca, const function_arg_info &arg),
4869 default_function_arg_advance)
4872 (function_arg_offset,
4873 "This hook returns the number of bytes to add to the offset of an\n\
4874 argument of type @var{type} and mode @var{mode} when passed in memory.\n\
4875 This is needed for the SPU, which passes @code{char} and @code{short}\n\
4876 arguments in the preferred slot that is in the middle of the quad word\n\
4877 instead of starting at the top. The default implementation returns 0.",
4878 HOST_WIDE_INT, (machine_mode mode, const_tree type),
4879 default_function_arg_offset)
4882 (function_arg_padding,
4883 "This hook determines whether, and in which direction, to pad out\n\
4884 an argument of mode @var{mode} and type @var{type}. It returns\n\
4885 @code{PAD_UPWARD} to insert padding above the argument, @code{PAD_DOWNWARD}\n\
4886 to insert padding below the argument, or @code{PAD_NONE} to inhibit padding.\n\
4888 The @emph{amount} of padding is not controlled by this hook, but by\n\
4889 @code{TARGET_FUNCTION_ARG_ROUND_BOUNDARY}. It is always just enough\n\
4890 to reach the next multiple of that boundary.\n\
4892 This hook has a default definition that is right for most systems.\n\
4893 For little-endian machines, the default is to pad upward. For\n\
4894 big-endian machines, the default is to pad downward for an argument of\n\
4895 constant size shorter than an @code{int}, and upward otherwise.",
4896 pad_direction, (machine_mode mode, const_tree type),
4897 default_function_arg_padding)
4899 /* Return zero if the argument described by the state of CA should
4900 be placed on a stack, or a hard register in which to store the
4901 argument. The values MODE, TYPE, and NAMED describe that
4905 "Return an RTX indicating whether function argument @var{arg} is passed\n\
4906 in a register and if so, which register. Argument @var{ca} summarizes all\n\
4907 the previous arguments.\n\
4909 The return value is usually either a @code{reg} RTX for the hard\n\
4910 register in which to pass the argument, or zero to pass the argument\n\
4913 The return value can be a @code{const_int} which means argument is\n\
4914 passed in a target specific slot with specified number. Target hooks\n\
4915 should be used to store or load argument in such case. See\n\
4916 @code{TARGET_STORE_BOUNDS_FOR_ARG} and @code{TARGET_LOAD_BOUNDS_FOR_ARG}\n\
4917 for more information.\n\
4919 The value of the expression can also be a @code{parallel} RTX@. This is\n\
4920 used when an argument is passed in multiple locations. The mode of the\n\
4921 @code{parallel} should be the mode of the entire argument. The\n\
4922 @code{parallel} holds any number of @code{expr_list} pairs; each one\n\
4923 describes where part of the argument is passed. In each\n\
4924 @code{expr_list} the first operand must be a @code{reg} RTX for the hard\n\
4925 register in which to pass this part of the argument, and the mode of the\n\
4926 register RTX indicates how large this part of the argument is. The\n\
4927 second operand of the @code{expr_list} is a @code{const_int} which gives\n\
4928 the offset in bytes into the entire argument of where this part starts.\n\
4929 As a special exception the first @code{expr_list} in the @code{parallel}\n\
4930 RTX may have a first operand of zero. This indicates that the entire\n\
4931 argument is also stored on the stack.\n\
4933 The last time this hook is called, it is called with @code{MODE ==\n\
4934 VOIDmode}, and its result is passed to the @code{call} or @code{call_value}\n\
4935 pattern as operands 2 and 3 respectively.\n\
4937 @cindex @file{stdarg.h} and register arguments\n\
4938 The usual way to make the ISO library @file{stdarg.h} work on a\n\
4939 machine where some arguments are usually passed in registers, is to\n\
4940 cause nameless arguments to be passed on the stack instead. This is\n\
4941 done by making @code{TARGET_FUNCTION_ARG} return 0 whenever\n\
4942 @var{named} is @code{false}.\n\
4944 @cindex @code{TARGET_MUST_PASS_IN_STACK}, and @code{TARGET_FUNCTION_ARG}\n\
4945 @cindex @code{REG_PARM_STACK_SPACE}, and @code{TARGET_FUNCTION_ARG}\n\
4946 You may use the hook @code{targetm.calls.must_pass_in_stack}\n\
4947 in the definition of this macro to determine if this argument is of a\n\
4948 type that must be passed in the stack. If @code{REG_PARM_STACK_SPACE}\n\
4949 is not defined and @code{TARGET_FUNCTION_ARG} returns nonzero for such an\n\
4950 argument, the compiler will abort. If @code{REG_PARM_STACK_SPACE} is\n\
4951 defined, the argument will be computed in the stack and then loaded into\n\
4953 rtx, (cumulative_args_t ca, const function_arg_info &arg),
4954 default_function_arg)
4957 (function_incoming_arg,
4958 "Define this hook if the caller and callee on the target have different\n\
4959 views of where arguments are passed. Also define this hook if there are\n\
4960 functions that are never directly called, but are invoked by the hardware\n\
4961 and which have nonstandard calling conventions.\n\
4963 In this case @code{TARGET_FUNCTION_ARG} computes the register in\n\
4964 which the caller passes the value, and\n\
4965 @code{TARGET_FUNCTION_INCOMING_ARG} should be defined in a similar\n\
4966 fashion to tell the function being called where the arguments will\n\
4969 @code{TARGET_FUNCTION_INCOMING_ARG} can also return arbitrary address\n\
4970 computation using hard register, which can be forced into a register,\n\
4971 so that it can be used to pass special arguments.\n\
4973 If @code{TARGET_FUNCTION_INCOMING_ARG} is not defined,\n\
4974 @code{TARGET_FUNCTION_ARG} serves both purposes.",
4975 rtx, (cumulative_args_t ca, const function_arg_info &arg),
4976 default_function_incoming_arg)
4979 (function_arg_boundary,
4980 "This hook returns the alignment boundary, in bits, of an argument\n\
4981 with the specified mode and type. The default hook returns\n\
4982 @code{PARM_BOUNDARY} for all arguments.",
4983 unsigned int, (machine_mode mode, const_tree type),
4984 default_function_arg_boundary)
4987 (function_arg_round_boundary,
4988 "Normally, the size of an argument is rounded up to @code{PARM_BOUNDARY},\n\
4989 which is the default value for this hook. You can define this hook to\n\
4990 return a different value if an argument size must be rounded to a larger\n\
4992 unsigned int, (machine_mode mode, const_tree type),
4993 default_function_arg_round_boundary)
4995 /* Return the diagnostic message string if function without a prototype
4996 is not allowed for this 'val' argument; NULL otherwise. */
4998 (invalid_arg_for_unprototyped_fn,
4999 "If defined, this macro returns the diagnostic message when it is\n\
5000 illegal to pass argument @var{val} to function @var{funcdecl}\n\
5001 with prototype @var{typelist}.",
5002 const char *, (const_tree typelist, const_tree funcdecl, const_tree val),
5003 hook_invalid_arg_for_unprototyped_fn)
5005 /* Return an rtx for the return value location of the function
5006 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
5010 Define this to return an RTX representing the place where a function\n\
5011 returns or receives a value of data type @var{ret_type}, a tree node\n\
5012 representing a data type. @var{fn_decl_or_type} is a tree node\n\
5013 representing @code{FUNCTION_DECL} or @code{FUNCTION_TYPE} of a\n\
5014 function being called. If @var{outgoing} is false, the hook should\n\
5015 compute the register in which the caller will see the return value.\n\
5016 Otherwise, the hook should return an RTX representing the place where\n\
5017 a function returns a value.\n\
5019 On many machines, only @code{TYPE_MODE (@var{ret_type})} is relevant.\n\
5020 (Actually, on most machines, scalar values are returned in the same\n\
5021 place regardless of mode.) The value of the expression is usually a\n\
5022 @code{reg} RTX for the hard register where the return value is stored.\n\
5023 The value can also be a @code{parallel} RTX, if the return value is in\n\
5024 multiple places. See @code{TARGET_FUNCTION_ARG} for an explanation of the\n\
5025 @code{parallel} form. Note that the callee will populate every\n\
5026 location specified in the @code{parallel}, but if the first element of\n\
5027 the @code{parallel} contains the whole return value, callers will use\n\
5028 that element as the canonical location and ignore the others. The m68k\n\
5029 port uses this type of @code{parallel} to return pointers in both\n\
5030 @samp{%a0} (the canonical location) and @samp{%d0}.\n\
5032 If @code{TARGET_PROMOTE_FUNCTION_RETURN} returns true, you must apply\n\
5033 the same promotion rules specified in @code{PROMOTE_MODE} if\n\
5034 @var{valtype} is a scalar type.\n\
5036 If the precise function being called is known, @var{func} is a tree\n\
5037 node (@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null\n\
5038 pointer. This makes it possible to use a different value-returning\n\
5039 convention for specific functions when all their calls are\n\
5042 Some target machines have ``register windows'' so that the register in\n\
5043 which a function returns its value is not the same as the one in which\n\
5044 the caller sees the value. For such machines, you should return\n\
5045 different RTX depending on @var{outgoing}.\n\
5047 @code{TARGET_FUNCTION_VALUE} is not used for return values with\n\
5048 aggregate data types, because these are returned in another way. See\n\
5049 @code{TARGET_STRUCT_VALUE_RTX} and related macros, below.",
5050 rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
5051 default_function_value)
5053 /* Return the rtx for the result of a libcall of mode MODE,
5054 calling the function FN_NAME. */
5057 "Define this hook if the back-end needs to know the name of the libcall\n\
5058 function in order to determine where the result should be returned.\n\
5060 The mode of the result is given by @var{mode} and the name of the called\n\
5061 library function is given by @var{fun}. The hook should return an RTX\n\
5062 representing the place where the library function result will be returned.\n\
5064 If this hook is not defined, then LIBCALL_VALUE will be used.",
5065 rtx, (machine_mode mode, const_rtx fun),
5066 default_libcall_value)
5068 /* Return true if REGNO is a possible register number for
5069 a function value as seen by the caller. */
5071 (function_value_regno_p,
5072 "A target hook that return @code{true} if @var{regno} is the number of a hard\n\
5073 register in which the values of called function may come back.\n\
5075 A register whose use for returning values is limited to serving as the\n\
5076 second of a pair (for a value of type @code{double}, say) need not be\n\
5077 recognized by this target hook.\n\
5079 If the machine has register windows, so that the caller and the called\n\
5080 function use different registers for the return value, this target hook\n\
5081 should recognize only the caller's register numbers.\n\
5083 If this hook is not defined, then FUNCTION_VALUE_REGNO_P will be used.",
5084 bool, (const unsigned int regno),
5085 default_function_value_regno_p)
5089 "Return the ABI used by a function with type @var{type}; see the\n\
5090 definition of @code{predefined_function_abi} for details of the ABI\n\
5091 descriptor. Targets only need to define this hook if they support\n\
5092 interoperability between several ABIs in the same translation unit.",
5093 const predefined_function_abi &, (const_tree type),
5098 "This hook returns a description of the ABI used by the target of\n\
5099 call instruction @var{insn}; see the definition of\n\
5100 @code{predefined_function_abi} for details of the ABI descriptor.\n\
5101 Only the global function @code{insn_callee_abi} should call this hook\n\
5104 Targets only need to define this hook if they support\n\
5105 interoperability between several ABIs in the same translation unit.",
5106 const predefined_function_abi &, (const rtx_insn *insn),
5109 /* ??? Documenting this hook requires a GFDL license grant. */
5111 (internal_arg_pointer,
5112 "Return an rtx for the argument pointer incoming to the\
5115 default_internal_arg_pointer)
5117 /* Update the current function stack boundary if needed. */
5119 (update_stack_boundary,
5120 "Define this macro to update the current function stack boundary if\n\
5124 /* Handle stack alignment and return an rtx for Dynamic Realign
5125 Argument Pointer if necessary. */
5128 "This hook should return an rtx for Dynamic Realign Argument Pointer (DRAP) if a\n\
5129 different argument pointer register is needed to access the function's\n\
5130 argument list due to stack realignment. Return @code{NULL} if no DRAP\n\
5134 /* Generate instruction sequence to zero call used registers. */
5136 (zero_call_used_regs,
5137 "This target hook emits instructions to zero the subset of @var{selected_regs}\n\
5138 that could conceivably contain values that are useful to an attacker.\n\
5139 Return the set of registers that were actually cleared.\n\
5141 The default implementation uses normal move instructions to zero\n\
5142 all the registers in @var{selected_regs}. Define this hook if the\n\
5143 target has more efficient ways of zeroing certain registers,\n\
5144 or if you believe that certain registers would never contain\n\
5145 values that are useful to an attacker.",
5146 HARD_REG_SET, (HARD_REG_SET selected_regs),
5147 default_zero_call_used_regs)
5149 /* Return true if all function parameters should be spilled to the
5152 (allocate_stack_slots_for_args,
5153 "When optimization is disabled, this hook indicates whether or not\n\
5154 arguments should be allocated to stack slots. Normally, GCC allocates\n\
5155 stacks slots for arguments when not optimizing in order to make\n\
5156 debugging easier. However, when a function is declared with\n\
5157 @code{__attribute__((naked))}, there is no stack frame, and the compiler\n\
5158 cannot safely move arguments from the registers in which they are passed\n\
5159 to the stack. Therefore, this hook should return true in general, but\n\
5160 false for naked functions. The default implementation always returns true.",
5162 hook_bool_void_true)
5164 /* Return an rtx for the static chain for FNDECL_OR_TYPE. If INCOMING_P
5165 is true, then it should be for the callee; otherwise for the caller. */
5168 "This hook replaces the use of @code{STATIC_CHAIN_REGNUM} et al for\n\
5169 targets that may use different static chain locations for different\n\
5170 nested functions. This may be required if the target has function\n\
5171 attributes that affect the calling conventions of the function and\n\
5172 those calling conventions use different static chain locations.\n\
5174 The default version of this hook uses @code{STATIC_CHAIN_REGNUM} et al.\n\
5176 If the static chain is passed in memory, this hook should be used to\n\
5177 provide rtx giving @code{mem} expressions that denote where they are stored.\n\
5178 Often the @code{mem} expression as seen by the caller will be at an offset\n\
5179 from the stack pointer and the @code{mem} expression as seen by the callee\n\
5180 will be at an offset from the frame pointer.\n\
5181 @findex stack_pointer_rtx\n\
5182 @findex frame_pointer_rtx\n\
5183 @findex arg_pointer_rtx\n\
5184 The variables @code{stack_pointer_rtx}, @code{frame_pointer_rtx}, and\n\
5185 @code{arg_pointer_rtx} will have been initialized and should be used\n\
5186 to refer to those items.",
5187 rtx, (const_tree fndecl_or_type, bool incoming_p),
5188 default_static_chain)
5190 /* Fill in the trampoline at MEM with a call to FNDECL and a
5191 static chain value of CHAIN. */
5194 "This hook is called to initialize a trampoline.\n\
5195 @var{m_tramp} is an RTX for the memory block for the trampoline; @var{fndecl}\n\
5196 is the @code{FUNCTION_DECL} for the nested function; @var{static_chain} is an\n\
5197 RTX for the static chain value that should be passed to the function\n\
5198 when it is called.\n\
5200 If the target defines @code{TARGET_ASM_TRAMPOLINE_TEMPLATE}, then the\n\
5201 first thing this hook should do is emit a block move into @var{m_tramp}\n\
5202 from the memory block returned by @code{assemble_trampoline_template}.\n\
5203 Note that the block move need only cover the constant parts of the\n\
5204 trampoline. If the target isolates the variable parts of the trampoline\n\
5205 to the end, not all @code{TRAMPOLINE_SIZE} bytes need be copied.\n\
5207 If the target requires any other actions, such as flushing caches\n\
5208 (possibly calling function maybe_emit_call_builtin___clear_cache) or\n\
5209 enabling stack execution, these actions should be performed after\n\
5210 initializing the trampoline proper.",
5211 void, (rtx m_tramp, tree fndecl, rtx static_chain),
5212 default_trampoline_init)
5214 /* Emit a call to a function to clear the instruction cache. */
5216 (emit_call_builtin___clear_cache,
5217 "On targets that do not define a @code{clear_cache} insn expander,\n\
5218 but that define the @code{CLEAR_CACHE_INSN} macro,\n\
5219 maybe_emit_call_builtin___clear_cache relies on this target hook\n\
5220 to clear an address range in the instruction cache.\n\
5222 The default implementation calls the @code{__clear_cache} builtin,\n\
5223 taking the assembler name from the builtin declaration. Overriding\n\
5224 definitions may call alternate functions, with alternate calling\n\
5225 conventions, or emit alternate RTX to perform the job.",
5226 void, (rtx begin, rtx end),
5227 default_emit_call_builtin___clear_cache)
5229 /* Adjust the address of the trampoline in a target-specific way. */
5231 (trampoline_adjust_address,
5232 "This hook should perform any machine-specific adjustment in\n\
5233 the address of the trampoline. Its argument contains the address of the\n\
5234 memory block that was passed to @code{TARGET_TRAMPOLINE_INIT}. In case\n\
5235 the address to be used for a function call should be different from the\n\
5236 address at which the template was stored, the different address should\n\
5237 be returned; otherwise @var{addr} should be returned unchanged.\n\
5238 If this hook is not defined, @var{addr} will be used for function calls.",
5239 rtx, (rtx addr), NULL)
5242 (custom_function_descriptors,
5243 "If the target can use GCC's generic descriptor mechanism for nested\n\
5244 functions, define this hook to a power of 2 representing an unused bit\n\
5245 in function pointers which can be used to differentiate descriptors at\n\
5246 run time. This value gives the number of bytes by which descriptor\n\
5247 pointers are misaligned compared to function pointers. For example, on\n\
5248 targets that require functions to be aligned to a 4-byte boundary, a\n\
5249 value of either 1 or 2 is appropriate unless the architecture already\n\
5250 reserves the bit for another purpose, such as on ARM.\n\
5252 Define this hook to 0 if the target implements ABI support for\n\
5253 function descriptors in its standard calling sequence, like for example\n\
5256 Using descriptors for nested functions\n\
5257 eliminates the need for trampolines that reside on the stack and require\n\
5258 it to be made executable.",\
5261 /* Return the number of bytes of its own arguments that a function
5262 pops on returning, or 0 if the function pops no arguments and the
5263 caller must therefore pop them all after the function returns. */
5264 /* ??? tm.texi has no types for the parameters. */
5267 "This target hook returns the number of bytes of its own arguments that\n\
5268 a function pops on returning, or 0 if the function pops no arguments\n\
5269 and the caller must therefore pop them all after the function returns.\n\
5271 @var{fundecl} is a C variable whose value is a tree node that describes\n\
5272 the function in question. Normally it is a node of type\n\
5273 @code{FUNCTION_DECL} that describes the declaration of the function.\n\
5274 From this you can obtain the @code{DECL_ATTRIBUTES} of the function.\n\
5276 @var{funtype} is a C variable whose value is a tree node that\n\
5277 describes the function in question. Normally it is a node of type\n\
5278 @code{FUNCTION_TYPE} that describes the data type of the function.\n\
5279 From this it is possible to obtain the data types of the value and\n\
5280 arguments (if known).\n\
5282 When a call to a library function is being considered, @var{fundecl}\n\
5283 will contain an identifier node for the library function. Thus, if\n\
5284 you need to distinguish among various library functions, you can do so\n\
5285 by their names. Note that ``library function'' in this context means\n\
5286 a function used to perform arithmetic, whose name is known specially\n\
5287 in the compiler and was not mentioned in the C code being compiled.\n\
5289 @var{size} is the number of bytes of arguments passed on the\n\
5290 stack. If a variable number of bytes is passed, it is zero, and\n\
5291 argument popping will always be the responsibility of the calling function.\n\
5293 On the VAX, all functions always pop their arguments, so the definition\n\
5294 of this macro is @var{size}. On the 68000, using the standard\n\
5295 calling convention, no functions pop their arguments, so the value of\n\
5296 the macro is always 0 in this case. But an alternative calling\n\
5297 convention is available in which functions that take a fixed number of\n\
5298 arguments pop them but other functions (such as @code{printf}) pop\n\
5299 nothing (the caller pops all). When this convention is in use,\n\
5300 @var{funtype} is examined to determine whether a function takes a fixed\n\
5301 number of arguments.",
5302 poly_int64, (tree fundecl, tree funtype, poly_int64 size),
5303 default_return_pops_args)
5305 /* Return a mode wide enough to copy any function value that might be
5308 (get_raw_result_mode,
5309 "This target hook returns the mode to be used when accessing raw return\
5310 registers in @code{__builtin_return}. Define this macro if the value\
5311 in @var{reg_raw_mode} is not correct.",
5312 fixed_size_mode, (int regno),
5313 default_get_reg_raw_mode)
5315 /* Return a mode wide enough to copy any argument value that might be
5319 "This target hook returns the mode to be used when accessing raw argument\
5320 registers in @code{__builtin_apply_args}. Define this macro if the value\
5321 in @var{reg_raw_mode} is not correct.",
5322 fixed_size_mode, (int regno),
5323 default_get_reg_raw_mode)
5325 /* Return true if a type is an empty record. */
5328 "This target hook returns true if the type is an empty record. The default\n\
5329 is to return @code{false}.",
5330 bool, (const_tree type),
5331 hook_bool_const_tree_false)
5333 /* Warn about the change in empty class parameter passing ABI. */
5335 (warn_parameter_passing_abi,
5336 "This target hook warns about the change in empty class parameter passing\n\
5338 void, (cumulative_args_t ca, tree type),
5339 hook_void_CUMULATIVE_ARGS_tree)
5341 HOOK_VECTOR_END (calls)
5344 (use_pseudo_pic_reg,
5345 "This hook should return 1 in case pseudo register should be created\n\
5346 for pic_offset_table_rtx during function expand.",
5348 hook_bool_void_false)
5352 "Perform a target dependent initialization of pic_offset_table_rtx.\n\
5353 This hook is called at the start of register allocation.",
5357 /* Return the diagnostic message string if conversion from FROMTYPE
5358 to TOTYPE is not allowed, NULL otherwise. */
5360 (invalid_conversion,
5361 "If defined, this macro returns the diagnostic message when it is\n\
5362 invalid to convert from @var{fromtype} to @var{totype}, or @code{NULL}\n\
5363 if validity should be determined by the front end.",
5364 const char *, (const_tree fromtype, const_tree totype),
5365 hook_constcharptr_const_tree_const_tree_null)
5367 /* Return the diagnostic message string if the unary operation OP is
5368 not permitted on TYPE, NULL otherwise. */
5371 "If defined, this macro returns the diagnostic message when it is\n\
5372 invalid to apply operation @var{op} (where unary plus is denoted by\n\
5373 @code{CONVERT_EXPR}) to an operand of type @var{type}, or @code{NULL}\n\
5374 if validity should be determined by the front end.",
5375 const char *, (int op, const_tree type),
5376 hook_constcharptr_int_const_tree_null)
5378 /* Return the diagnostic message string if the binary operation OP
5379 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
5382 "If defined, this macro returns the diagnostic message when it is\n\
5383 invalid to apply operation @var{op} to operands of types @var{type1}\n\
5384 and @var{type2}, or @code{NULL} if validity should be determined by\n\
5386 const char *, (int op, const_tree type1, const_tree type2),
5387 hook_constcharptr_int_const_tree_const_tree_null)
5389 /* If values of TYPE are promoted to some other type when used in
5390 expressions (analogous to the integer promotions), return that type,
5391 or NULL_TREE otherwise. */
5394 "If defined, this target hook returns the type to which values of\n\
5395 @var{type} should be promoted when they appear in expressions,\n\
5396 analogous to the integer promotions, or @code{NULL_TREE} to use the\n\
5397 front end's normal promotion rules. This hook is useful when there are\n\
5398 target-specific types with special promotion rules.\n\
5399 This is currently used only by the C and C++ front ends.",
5400 tree, (const_tree type),
5401 hook_tree_const_tree_null)
5403 /* Convert EXPR to TYPE, if target-specific types with special conversion
5404 rules are involved. Return the converted expression, or NULL to apply
5405 the standard conversion rules. */
5408 "If defined, this hook returns the result of converting @var{expr} to\n\
5409 @var{type}. It should return the converted expression,\n\
5410 or @code{NULL_TREE} to apply the front end's normal conversion rules.\n\
5411 This hook is useful when there are target-specific types with special\n\
5412 conversion rules.\n\
5413 This is currently used only by the C and C++ front ends.",
5414 tree, (tree type, tree expr),
5415 hook_tree_tree_tree_null)
5418 (verify_type_context,
5419 "If defined, this hook returns false if there is a target-specific reason\n\
5420 why type @var{type} cannot be used in the source language context described\n\
5421 by @var{context}. When @var{silent_p} is false, the hook also reports an\n\
5422 error against @var{loc} for invalid uses of @var{type}.\n\
5424 Calls to this hook should be made through the global function\n\
5425 @code{verify_type_context}, which makes the @var{silent_p} parameter\n\
5426 default to false and also handles @code{error_mark_node}.\n\
5428 The default implementation always returns true.",
5429 bool, (location_t loc, type_context_kind context, const_tree type,
5434 (can_change_mode_class,
5435 "This hook returns true if it is possible to bitcast values held in\n\
5436 registers of class @var{rclass} from mode @var{from} to mode @var{to}\n\
5437 and if doing so preserves the low-order bits that are common to both modes.\n\
5438 The result is only meaningful if @var{rclass} has registers that can hold\n\
5439 both @code{from} and @code{to}. The default implementation returns true.\n\
5441 As an example of when such bitcasting is invalid, loading 32-bit integer or\n\
5442 floating-point objects into floating-point registers on Alpha extends them\n\
5443 to 64 bits. Therefore loading a 64-bit object and then storing it as a\n\
5444 32-bit object does not store the low-order 32 bits, as would be the case\n\
5445 for a normal register. Therefore, @file{alpha.h} defines\n\
5446 @code{TARGET_CAN_CHANGE_MODE_CLASS} to return:\n\
5449 (GET_MODE_SIZE (from) == GET_MODE_SIZE (to)\n\
5450 || !reg_classes_intersect_p (FLOAT_REGS, rclass))\n\
5451 @end smallexample\n\
5453 Even if storing from a register in mode @var{to} would be valid,\n\
5454 if both @var{from} and @code{raw_reg_mode} for @var{rclass} are wider\n\
5455 than @code{word_mode}, then we must prevent @var{to} narrowing the\n\
5456 mode. This happens when the middle-end assumes that it can load\n\
5457 or store pieces of an @var{N}-word pseudo, and that the pseudo will\n\
5458 eventually be allocated to @var{N} @code{word_mode} hard registers.\n\
5459 Failure to prevent this kind of mode change will result in the\n\
5460 entire @code{raw_reg_mode} being modified instead of the partial\n\
5461 value that the middle-end intended.",
5462 bool, (machine_mode from, machine_mode to, reg_class_t rclass),
5463 hook_bool_mode_mode_reg_class_t_true)
5465 /* Change pseudo allocno class calculated by IRA. */
5467 (ira_change_pseudo_allocno_class,
5468 "A target hook which can change allocno class for given pseudo from\n\
5469 allocno and best class calculated by IRA.\n\
5471 The default version of this target hook always returns given class.",
5472 reg_class_t, (int, reg_class_t, reg_class_t),
5473 default_ira_change_pseudo_allocno_class)
5475 /* Return true if we use LRA instead of reload. */
5478 "A target hook which returns true if we use LRA instead of reload pass.\
5480 The default version of this target hook returns true. New ports\
5481 should use LRA, and existing ports are encouraged to convert.",
5485 /* Return register priority of given hard regno for the current target. */
5488 "A target hook which returns the register priority number to which the\
5489 register @var{hard_regno} belongs to. The bigger the number, the\
5490 more preferable the hard register usage (when all other conditions are\
5491 the same). This hook can be used to prefer some hard register over\
5492 others in LRA. For example, some x86-64 register usage needs\
5493 additional prefix which makes instructions longer. The hook can\
5494 return lower priority number for such registers make them less favorable\
5495 and as result making the generated code smaller.\
5497 The default version of this target hook returns always zero.",
5499 default_register_priority)
5501 /* Return true if we need register usage leveling. */
5503 (register_usage_leveling_p,
5504 "A target hook which returns true if we need register usage leveling.\
5505 That means if a few hard registers are equally good for the\
5506 assignment, we choose the least used hard register. The register\
5507 usage leveling may be profitable for some targets. Don't use the\
5508 usage leveling for targets with conditional execution or targets\
5509 with big register files as it hurts if-conversion and cross-jumping\
5512 The default version of this target hook returns always false.",
5514 default_register_usage_leveling_p)
5516 /* Return true if maximal address displacement can be different. */
5518 (different_addr_displacement_p,
5519 "A target hook which returns true if an address with the same structure\
5520 can have different maximal legitimate displacement. For example, the\
5521 displacement can depend on memory mode or on operand combinations in\
5524 The default version of this target hook returns always false.",
5526 default_different_addr_displacement_p)
5528 /* Determine class for spilling pseudos of given mode into registers
5529 instead of memory. */
5532 "This hook defines a class of registers which could be used for spilling\
5533 pseudos of the given mode and class, or @code{NO_REGS} if only memory\
5534 should be used. Not defining this hook is equivalent to returning\
5535 @code{NO_REGS} for all inputs.",
5536 reg_class_t, (reg_class_t, machine_mode),
5539 /* Determine an additional allocno class. */
5541 (additional_allocno_class_p,
5542 "This hook should return @code{true} if given class of registers should\
5543 be an allocno class in any way. Usually RA uses only one register\
5544 class from all classes containing the same register set. In some\
5545 complicated cases, you need to have two or more such classes as\
5546 allocno ones for RA correct work. Not defining this hook is\
5547 equivalent to returning @code{false} for all inputs.",
5548 bool, (reg_class_t),
5549 hook_bool_reg_class_t_false)
5553 "This hook defines the machine mode to use for the boolean result of\
5554 conditional store patterns. The ICODE argument is the instruction code\
5555 for the cstore being performed. Not definiting this hook is the same\
5556 as accepting the mode encoded into operand 0 of the cstore expander\
5558 scalar_int_mode, (enum insn_code icode),
5559 default_cstore_mode)
5561 /* This target hook allows the backend to compute the register pressure
5564 (compute_pressure_classes,
5565 "A target hook which lets a backend compute the set of pressure classes to\
5566 be used by those optimization passes which take register pressure into\
5567 account, as opposed to letting IRA compute them. It returns the number of\
5568 register classes stored in the array @var{pressure_classes}.",
5569 int, (enum reg_class *pressure_classes), NULL)
5571 /* True if a structure, union or array with MODE containing FIELD should
5572 be accessed using BLKmode. */
5574 (member_type_forces_blk,
5575 "Return true if a structure, union or array containing @var{field} should\n\
5576 be accessed using @code{BLKMODE}.\n\
5578 If @var{field} is the only field in the structure, @var{mode} is its\n\
5579 mode, otherwise @var{mode} is VOIDmode. @var{mode} is provided in the\n\
5580 case where structures of one field would require the structure's mode to\n\
5581 retain the field's mode.\n\
5583 Normally, this is not needed.",
5584 bool, (const_tree field, machine_mode mode),
5585 default_member_type_forces_blk)
5587 /* See tree-ssa-math-opts.c:divmod_candidate_p for conditions
5588 that gate the divod transform. */
5590 (expand_divmod_libfunc,
5591 "Define this hook for enabling divmod transform if the port does not have\n\
5592 hardware divmod insn but defines target-specific divmod libfuncs.",
5593 void, (rtx libfunc, machine_mode mode, rtx op0, rtx op1, rtx *quot, rtx *rem),
5596 /* Return the class for a secondary reload, and fill in extra information. */
5599 "Many machines have some registers that cannot be copied directly to or\n\
5600 from memory or even from other types of registers. An example is the\n\
5601 @samp{MQ} register, which on most machines, can only be copied to or\n\
5602 from general registers, but not memory. Below, we shall be using the\n\
5603 term 'intermediate register' when a move operation cannot be performed\n\
5604 directly, but has to be done by copying the source into the intermediate\n\
5605 register first, and then copying the intermediate register to the\n\
5606 destination. An intermediate register always has the same mode as\n\
5607 source and destination. Since it holds the actual value being copied,\n\
5608 reload might apply optimizations to re-use an intermediate register\n\
5609 and eliding the copy from the source when it can determine that the\n\
5610 intermediate register still holds the required value.\n\
5612 Another kind of secondary reload is required on some machines which\n\
5613 allow copying all registers to and from memory, but require a scratch\n\
5614 register for stores to some memory locations (e.g., those with symbolic\n\
5615 address on the RT, and those with certain symbolic address on the SPARC\n\
5616 when compiling PIC)@. Scratch registers need not have the same mode\n\
5617 as the value being copied, and usually hold a different value than\n\
5618 that being copied. Special patterns in the md file are needed to\n\
5619 describe how the copy is performed with the help of the scratch register;\n\
5620 these patterns also describe the number, register class(es) and mode(s)\n\
5621 of the scratch register(s).\n\
5623 In some cases, both an intermediate and a scratch register are required.\n\
5625 For input reloads, this target hook is called with nonzero @var{in_p},\n\
5626 and @var{x} is an rtx that needs to be copied to a register of class\n\
5627 @var{reload_class} in @var{reload_mode}. For output reloads, this target\n\
5628 hook is called with zero @var{in_p}, and a register of class @var{reload_class}\n\
5629 needs to be copied to rtx @var{x} in @var{reload_mode}.\n\
5631 If copying a register of @var{reload_class} from/to @var{x} requires\n\
5632 an intermediate register, the hook @code{secondary_reload} should\n\
5633 return the register class required for this intermediate register.\n\
5634 If no intermediate register is required, it should return NO_REGS.\n\
5635 If more than one intermediate register is required, describe the one\n\
5636 that is closest in the copy chain to the reload register.\n\
5638 If scratch registers are needed, you also have to describe how to\n\
5639 perform the copy from/to the reload register to/from this\n\
5640 closest intermediate register. Or if no intermediate register is\n\
5641 required, but still a scratch register is needed, describe the\n\
5642 copy from/to the reload register to/from the reload operand @var{x}.\n\
5644 You do this by setting @code{sri->icode} to the instruction code of a pattern\n\
5645 in the md file which performs the move. Operands 0 and 1 are the output\n\
5646 and input of this copy, respectively. Operands from operand 2 onward are\n\
5647 for scratch operands. These scratch operands must have a mode, and a\n\
5648 single-register-class\n\
5649 @c [later: or memory]\n\
5650 output constraint.\n\
5652 When an intermediate register is used, the @code{secondary_reload}\n\
5653 hook will be called again to determine how to copy the intermediate\n\
5654 register to/from the reload operand @var{x}, so your hook must also\n\
5655 have code to handle the register class of the intermediate operand.\n\
5657 @c [For later: maybe we'll allow multi-alternative reload patterns -\n\
5658 @c the port maintainer could name a mov<mode> pattern that has clobbers -\n\
5659 @c and match the constraints of input and output to determine the required\n\
5660 @c alternative. A restriction would be that constraints used to match\n\
5661 @c against reloads registers would have to be written as register class\n\
5662 @c constraints, or we need a new target macro / hook that tells us if an\n\
5663 @c arbitrary constraint can match an unknown register of a given class.\n\
5664 @c Such a macro / hook would also be useful in other places.]\n\
5667 @var{x} might be a pseudo-register or a @code{subreg} of a\n\
5668 pseudo-register, which could either be in a hard register or in memory.\n\
5669 Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is\n\
5670 in memory and the hard register number if it is in a register.\n\
5672 Scratch operands in memory (constraint @code{\"=m\"} / @code{\"=&m\"}) are\n\
5673 currently not supported. For the time being, you will have to continue\n\
5674 to use @code{TARGET_SECONDARY_MEMORY_NEEDED} for that purpose.\n\
5676 @code{copy_cost} also uses this target hook to find out how values are\n\
5677 copied. If you want it to include some extra cost for the need to allocate\n\
5678 (a) scratch register(s), set @code{sri->extra_cost} to the additional cost.\n\
5679 Or if two dependent moves are supposed to have a lower cost than the sum\n\
5680 of the individual moves due to expected fortuitous scheduling and/or special\n\
5681 forwarding logic, you can set @code{sri->extra_cost} to a negative amount.",
5683 (bool in_p, rtx x, reg_class_t reload_class, machine_mode reload_mode,
5684 secondary_reload_info *sri),
5685 default_secondary_reload)
5688 (secondary_memory_needed,
5689 "Certain machines have the property that some registers cannot be copied\n\
5690 to some other registers without using memory. Define this hook on\n\
5691 those machines to return true if objects of mode @var{m} in registers\n\
5692 of @var{class1} can only be copied to registers of class @var{class2} by\n\
5693 storing a register of @var{class1} into memory and loading that memory\n\
5694 location into a register of @var{class2}. The default definition returns\n\
5695 false for all inputs.",
5696 bool, (machine_mode mode, reg_class_t class1, reg_class_t class2),
5697 hook_bool_mode_reg_class_t_reg_class_t_false)
5700 (secondary_memory_needed_mode,
5701 "If @code{TARGET_SECONDARY_MEMORY_NEEDED} tells the compiler to use memory\n\
5702 when moving between two particular registers of mode @var{mode},\n\
5703 this hook specifies the mode that the memory should have.\n\
5705 The default depends on @code{TARGET_LRA_P}. Without LRA, the default\n\
5706 is to use a word-sized mode for integral modes that are smaller than a\n\
5707 a word. This is right thing to do on most machines because it ensures\n\
5708 that all bits of the register are copied and prevents accesses to the\n\
5709 registers in a narrower mode, which some machines prohibit for\n\
5710 floating-point registers.\n\
5712 However, this default behavior is not correct on some machines, such as\n\
5713 the DEC Alpha, that store short integers in floating-point registers\n\
5714 differently than in integer registers. On those machines, the default\n\
5715 widening will not work correctly and you must define this hook to\n\
5716 suppress that widening in some cases. See the file @file{alpha.c} for\n\
5719 With LRA, the default is to use @var{mode} unmodified.",
5720 machine_mode, (machine_mode mode),
5721 default_secondary_memory_needed_mode)
5723 /* Given an rtx X being reloaded into a reg required to be in class CLASS,
5724 return the class of reg to actually use. */
5726 (preferred_reload_class,
5727 "A target hook that places additional restrictions on the register class\n\
5728 to use when it is necessary to copy value @var{x} into a register in class\n\
5729 @var{rclass}. The value is a register class; perhaps @var{rclass}, or perhaps\n\
5730 another, smaller class.\n\
5732 The default version of this hook always returns value of @code{rclass} argument.\n\
5734 Sometimes returning a more restrictive class makes better code. For\n\
5735 example, on the 68000, when @var{x} is an integer constant that is in range\n\
5736 for a @samp{moveq} instruction, the value of this macro is always\n\
5737 @code{DATA_REGS} as long as @var{rclass} includes the data registers.\n\
5738 Requiring a data register guarantees that a @samp{moveq} will be used.\n\
5740 One case where @code{TARGET_PREFERRED_RELOAD_CLASS} must not return\n\
5741 @var{rclass} is if @var{x} is a legitimate constant which cannot be\n\
5742 loaded into some register class. By returning @code{NO_REGS} you can\n\
5743 force @var{x} into a memory location. For example, rs6000 can load\n\
5744 immediate values into general-purpose registers, but does not have an\n\
5745 instruction for loading an immediate value into a floating-point\n\
5746 register, so @code{TARGET_PREFERRED_RELOAD_CLASS} returns @code{NO_REGS} when\n\
5747 @var{x} is a floating-point constant. If the constant can't be loaded\n\
5748 into any kind of register, code generation will be better if\n\
5749 @code{TARGET_LEGITIMATE_CONSTANT_P} makes the constant illegitimate instead\n\
5750 of using @code{TARGET_PREFERRED_RELOAD_CLASS}.\n\
5752 If an insn has pseudos in it after register allocation, reload will go\n\
5753 through the alternatives and call repeatedly @code{TARGET_PREFERRED_RELOAD_CLASS}\n\
5754 to find the best one. Returning @code{NO_REGS}, in this case, makes\n\
5755 reload add a @code{!} in front of the constraint: the x86 back-end uses\n\
5756 this feature to discourage usage of 387 registers when math is done in\n\
5757 the SSE registers (and vice versa).",
5759 (rtx x, reg_class_t rclass),
5760 default_preferred_reload_class)
5762 /* Like TARGET_PREFERRED_RELOAD_CLASS, but for output reloads instead of
5765 (preferred_output_reload_class,
5766 "Like @code{TARGET_PREFERRED_RELOAD_CLASS}, but for output reloads instead of\n\
5769 The default version of this hook always returns value of @code{rclass}\n\
5772 You can also use @code{TARGET_PREFERRED_OUTPUT_RELOAD_CLASS} to discourage\n\
5773 reload from using some alternatives, like @code{TARGET_PREFERRED_RELOAD_CLASS}.",
5775 (rtx x, reg_class_t rclass),
5776 default_preferred_output_reload_class)
5779 (select_early_remat_modes,
5780 "On some targets, certain modes cannot be held in registers around a\n\
5781 standard ABI call and are relatively expensive to spill to the stack.\n\
5782 The early rematerialization pass can help in such cases by aggressively\n\
5783 recomputing values after calls, so that they don't need to be spilled.\n\
5785 This hook returns the set of such modes by setting the associated bits\n\
5786 in @var{modes}. The default implementation selects no modes, which has\n\
5787 the effect of disabling the early rematerialization pass.",
5788 void, (sbitmap modes),
5789 default_select_early_remat_modes)
5792 (class_likely_spilled_p,
5793 "A target hook which returns @code{true} if pseudos that have been assigned\n\
5794 to registers of class @var{rclass} would likely be spilled because\n\
5795 registers of @var{rclass} are needed for spill registers.\n\
5797 The default version of this target hook returns @code{true} if @var{rclass}\n\
5798 has exactly one register and @code{false} otherwise. On most machines, this\n\
5799 default should be used. For generally register-starved machines, such as\n\
5800 i386, or machines with right register constraints, such as SH, this hook\n\
5801 can be used to avoid excessive spilling.\n\
5803 This hook is also used by some of the global intra-procedural code\n\
5804 transformations to throtle code motion, to avoid increasing register\n\
5806 bool, (reg_class_t rclass),
5807 default_class_likely_spilled_p)
5809 /* Return the maximum number of consecutive registers
5810 needed to represent mode MODE in a register of class RCLASS. */
5813 "A target hook returns the maximum number of consecutive registers\n\
5814 of class @var{rclass} needed to hold a value of mode @var{mode}.\n\
5816 This is closely related to the macro @code{TARGET_HARD_REGNO_NREGS}.\n\
5817 In fact, the value returned by @code{TARGET_CLASS_MAX_NREGS (@var{rclass},\n\
5818 @var{mode})} target hook should be the maximum value of\n\
5819 @code{TARGET_HARD_REGNO_NREGS (@var{regno}, @var{mode})} for all @var{regno}\n\
5820 values in the class @var{rclass}.\n\
5822 This target hook helps control the handling of multiple-word values\n\
5823 in the reload pass.\n\
5825 The default version of this target hook returns the size of @var{mode}\n\
5827 unsigned char, (reg_class_t rclass, machine_mode mode),
5828 default_class_max_nregs)
5831 (preferred_rename_class,
5832 "A target hook that places additional preference on the register\
5833 class to use when it is necessary to rename a register in class\
5834 @var{rclass} to another class, or perhaps @var{NO_REGS}, if no\
5835 preferred register class is found or hook @code{preferred_rename_class}\
5836 is not implemented.\
5837 Sometimes returning a more restrictive class makes better code. For\
5838 example, on ARM, thumb-2 instructions using @code{LO_REGS} may be\
5839 smaller than instructions using @code{GENERIC_REGS}. By returning\
5840 @code{LO_REGS} from @code{preferred_rename_class}, code size can\
5842 reg_class_t, (reg_class_t rclass),
5843 default_preferred_rename_class)
5845 /* This target hook allows the backend to avoid unsafe substitution
5846 during register allocation. */
5848 (cannot_substitute_mem_equiv_p,
5849 "A target hook which returns @code{true} if @var{subst} can't\n\
5850 substitute safely pseudos with equivalent memory values during\n\
5851 register allocation.\n\
5852 The default version of this target hook returns @code{false}.\n\
5853 On most machines, this default should be used. For generally\n\
5854 machines with non orthogonal register usage for addressing, such\n\
5855 as SH, this hook can be used to avoid excessive spilling.",
5857 hook_bool_rtx_false)
5859 /* This target hook allows the backend to legitimize base plus
5860 displacement addressing. */
5862 (legitimize_address_displacement,
5863 "This hook tries to split address offset @var{orig_offset} into\n\
5864 two parts: one that should be added to the base address to create\n\
5865 a local anchor point, and an additional offset that can be applied\n\
5866 to the anchor to address a value of mode @var{mode}. The idea is that\n\
5867 the local anchor could be shared by other accesses to nearby locations.\n\
5869 The hook returns true if it succeeds, storing the offset of the\n\
5870 anchor from the base in @var{offset1} and the offset of the final address\n\
5871 from the anchor in @var{offset2}. The default implementation returns false.",
5872 bool, (rtx *offset1, rtx *offset2, poly_int64 orig_offset, machine_mode mode),
5873 default_legitimize_address_displacement)
5875 /* This target hook allows the backend to perform additional
5876 processing while initializing for variable expansion. */
5878 (expand_to_rtl_hook,
5879 "This hook is called just before expansion into rtl, allowing the target\n\
5880 to perform additional initializations or analysis before the expansion.\n\
5881 For example, the rs6000 port uses it to allocate a scratch stack slot\n\
5882 for use in copying SDmode values between memory and floating point\n\
5883 registers whenever the function being expanded has any SDmode\n\
5888 /* This target hook allows the backend to perform additional
5889 instantiations on rtx that are not actually in insns yet,
5890 but will be later. */
5893 "This hook allows the backend to perform additional instantiations on rtl\n\
5894 that are not actually in any insns yet, but will be later.",
5900 "This hook returns the number of consecutive hard registers, starting\n\
5901 at register number @var{regno}, required to hold a value of mode\n\
5902 @var{mode}. This hook must never return zero, even if a register\n\
5903 cannot hold the requested mode - indicate that with\n\
5904 @code{TARGET_HARD_REGNO_MODE_OK} and/or\n\
5905 @code{TARGET_CAN_CHANGE_MODE_CLASS} instead.\n\
5907 The default definition returns the number of words in @var{mode}.",
5908 unsigned int, (unsigned int regno, machine_mode mode),
5909 default_hard_regno_nregs)
5912 (hard_regno_mode_ok,
5913 "This hook returns true if it is permissible to store a value\n\
5914 of mode @var{mode} in hard register number @var{regno} (or in several\n\
5915 registers starting with that one). The default definition returns true\n\
5918 You need not include code to check for the numbers of fixed registers,\n\
5919 because the allocation mechanism considers them to be always occupied.\n\
5921 @cindex register pairs\n\
5922 On some machines, double-precision values must be kept in even/odd\n\
5923 register pairs. You can implement that by defining this hook to reject\n\
5924 odd register numbers for such modes.\n\
5926 The minimum requirement for a mode to be OK in a register is that the\n\
5927 @samp{mov@var{mode}} instruction pattern support moves between the\n\
5928 register and other hard register in the same class and that moving a\n\
5929 value into the register and back out not alter it.\n\
5931 Since the same instruction used to move @code{word_mode} will work for\n\
5932 all narrower integer modes, it is not necessary on any machine for\n\
5933 this hook to distinguish between these modes, provided you define\n\
5934 patterns @samp{movhi}, etc., to take advantage of this. This is\n\
5935 useful because of the interaction between @code{TARGET_HARD_REGNO_MODE_OK}\n\
5936 and @code{TARGET_MODES_TIEABLE_P}; it is very desirable for all integer\n\
5937 modes to be tieable.\n\
5939 Many machines have special registers for floating point arithmetic.\n\
5940 Often people assume that floating point machine modes are allowed only\n\
5941 in floating point registers. This is not true. Any registers that\n\
5942 can hold integers can safely @emph{hold} a floating point machine\n\
5943 mode, whether or not floating arithmetic can be done on it in those\n\
5944 registers. Integer move instructions can be used to move the values.\n\
5946 On some machines, though, the converse is true: fixed-point machine\n\
5947 modes may not go in floating registers. This is true if the floating\n\
5948 registers normalize any value stored in them, because storing a\n\
5949 non-floating value there would garble it. In this case,\n\
5950 @code{TARGET_HARD_REGNO_MODE_OK} should reject fixed-point machine modes in\n\
5951 floating registers. But if the floating registers do not automatically\n\
5952 normalize, if you can store any bit pattern in one and retrieve it\n\
5953 unchanged without a trap, then any machine mode may go in a floating\n\
5954 register, so you can define this hook to say so.\n\
5956 The primary significance of special floating registers is rather that\n\
5957 they are the registers acceptable in floating point arithmetic\n\
5958 instructions. However, this is of no concern to\n\
5959 @code{TARGET_HARD_REGNO_MODE_OK}. You handle it by writing the proper\n\
5960 constraints for those instructions.\n\
5962 On some machines, the floating registers are especially slow to access,\n\
5963 so that it is better to store a value in a stack frame than in such a\n\
5964 register if floating point arithmetic is not being done. As long as the\n\
5965 floating registers are not in class @code{GENERAL_REGS}, they will not\n\
5966 be used unless some pattern's constraint asks for one.",
5967 bool, (unsigned int regno, machine_mode mode),
5968 hook_bool_uint_mode_true)
5972 "This hook returns true if a value of mode @var{mode1} is accessible\n\
5973 in mode @var{mode2} without copying.\n\
5975 If @code{TARGET_HARD_REGNO_MODE_OK (@var{r}, @var{mode1})} and\n\
5976 @code{TARGET_HARD_REGNO_MODE_OK (@var{r}, @var{mode2})} are always\n\
5977 the same for any @var{r}, then\n\
5978 @code{TARGET_MODES_TIEABLE_P (@var{mode1}, @var{mode2})}\n\
5979 should be true. If they differ for any @var{r}, you should define\n\
5980 this hook to return false unless some other mechanism ensures the\n\
5981 accessibility of the value in a narrower mode.\n\
5983 You should define this hook to return true in as many cases as\n\
5984 possible since doing so will allow GCC to perform better register\n\
5985 allocation. The default definition returns true unconditionally.",
5986 bool, (machine_mode mode1, machine_mode mode2),
5987 hook_bool_mode_mode_true)
5989 /* Return true if is OK to use a hard register REGNO as scratch register
5992 (hard_regno_scratch_ok,
5993 "This target hook should return @code{true} if it is OK to use a hard register\n\
5994 @var{regno} as scratch reg in peephole2.\n\
5996 One common use of this macro is to prevent using of a register that\n\
5997 is not saved by a prologue in an interrupt handler.\n\
5999 The default version of this hook always returns @code{true}.",
6000 bool, (unsigned int regno),
6001 default_hard_regno_scratch_ok)
6004 (hard_regno_call_part_clobbered,
6005 "ABIs usually specify that calls must preserve the full contents\n\
6006 of a particular register, or that calls can alter any part of a\n\
6007 particular register. This information is captured by the target macro\n\
6008 @code{CALL_REALLY_USED_REGISTERS}. However, some ABIs specify that calls\n\
6009 must preserve certain bits of a particular register but can alter others.\n\
6010 This hook should return true if this applies to at least one of the\n\
6011 registers in @samp{(reg:@var{mode} @var{regno})}, and if as a result the\n\
6012 call would alter part of the @var{mode} value. For example, if a call\n\
6013 preserves the low 32 bits of a 64-bit hard register @var{regno} but can\n\
6014 clobber the upper 32 bits, this hook should return true for a 64-bit mode\n\
6015 but false for a 32-bit mode.\n\
6017 The value of @var{abi_id} comes from the @code{predefined_function_abi}\n\
6018 structure that describes the ABI of the call; see the definition of the\n\
6019 structure for more details. If (as is usual) the target uses the same ABI\n\
6020 for all functions in a translation unit, @var{abi_id} is always 0.\n\
6022 The default implementation returns false, which is correct\n\
6023 for targets that don't have partly call-clobbered registers.",
6024 bool, (unsigned int abi_id, unsigned int regno, machine_mode mode),
6025 hook_bool_uint_uint_mode_false)
6028 (get_multilib_abi_name,
6029 "This hook returns name of multilib ABI name.",
6030 const char *, (void),
6031 hook_constcharptr_void_null)
6033 /* Return the smallest number of different values for which it is best to
6034 use a jump-table instead of a tree of conditional branches. */
6036 (case_values_threshold,
6037 "This function return the smallest number of different values for which it\n\
6038 is best to use a jump-table instead of a tree of conditional branches.\n\
6039 The default is four for machines with a @code{casesi} instruction and\n\
6040 five otherwise. This is best for most machines.",
6041 unsigned int, (void),
6042 default_case_values_threshold)
6045 (starting_frame_offset,
6046 "This hook returns the offset from the frame pointer to the first local\n\
6047 variable slot to be allocated. If @code{FRAME_GROWS_DOWNWARD}, it is the\n\
6048 offset to @emph{end} of the first slot allocated, otherwise it is the\n\
6049 offset to @emph{beginning} of the first slot allocated. The default\n\
6050 implementation returns 0.",
6051 HOST_WIDE_INT, (void),
6054 /* Optional callback to advise the target to compute the frame layout. */
6056 (compute_frame_layout,
6057 "This target hook is called once each time the frame layout needs to be\n\
6058 recalculated. The calculations can be cached by the target and can then\n\
6059 be used by @code{INITIAL_ELIMINATION_OFFSET} instead of re-computing the\n\
6060 layout on every invocation of that hook. This is particularly useful\n\
6061 for targets that have an expensive frame layout function. Implementing\n\
6062 this callback is optional.",
6066 /* Return true if a function must have and use a frame pointer. */
6068 (frame_pointer_required,
6069 "This target hook should return @code{true} if a function must have and use\n\
6070 a frame pointer. This target hook is called in the reload pass. If its return\n\
6071 value is @code{true} the function will have a frame pointer.\n\
6073 This target hook can in principle examine the current function and decide\n\
6074 according to the facts, but on most machines the constant @code{false} or the\n\
6075 constant @code{true} suffices. Use @code{false} when the machine allows code\n\
6076 to be generated with no frame pointer, and doing so saves some time or space.\n\
6077 Use @code{true} when there is no possible advantage to avoiding a frame\n\
6080 In certain cases, the compiler does not know how to produce valid code\n\
6081 without a frame pointer. The compiler recognizes those cases and\n\
6082 automatically gives the function a frame pointer regardless of what\n\
6083 @code{targetm.frame_pointer_required} returns. You don't need to worry about\n\
6086 In a function that does not require a frame pointer, the frame pointer\n\
6087 register can be allocated for ordinary usage, unless you mark it as a\n\
6088 fixed register. See @code{FIXED_REGISTERS} for more information.\n\
6090 Default return value is @code{false}.",
6092 hook_bool_void_false)
6094 /* Returns true if the compiler is allowed to try to replace register number
6095 from-reg with register number to-reg. */
6098 "This target hook should return @code{true} if the compiler is allowed to\n\
6099 try to replace register number @var{from_reg} with register number\n\
6100 @var{to_reg}. This target hook will usually be @code{true}, since most of the\n\
6101 cases preventing register elimination are things that the compiler already\n\
6104 Default return value is @code{true}.",
6105 bool, (const int from_reg, const int to_reg),
6106 hook_bool_const_int_const_int_true)
6108 /* Modify any or all of fixed_regs, call_used_regs, global_regs,
6109 reg_names, and reg_class_contents to account of the vagaries of the
6112 (conditional_register_usage,
6113 "This hook may conditionally modify five variables\n\
6114 @code{fixed_regs}, @code{call_used_regs}, @code{global_regs},\n\
6115 @code{reg_names}, and @code{reg_class_contents}, to take into account\n\
6116 any dependence of these register sets on target flags. The first three\n\
6117 of these are of type @code{char []} (interpreted as boolean vectors).\n\
6118 @code{global_regs} is a @code{const char *[]}, and\n\
6119 @code{reg_class_contents} is a @code{HARD_REG_SET}. Before the macro is\n\
6120 called, @code{fixed_regs}, @code{call_used_regs},\n\
6121 @code{reg_class_contents}, and @code{reg_names} have been initialized\n\
6122 from @code{FIXED_REGISTERS}, @code{CALL_USED_REGISTERS},\n\
6123 @code{REG_CLASS_CONTENTS}, and @code{REGISTER_NAMES}, respectively.\n\
6124 @code{global_regs} has been cleared, and any @option{-ffixed-@var{reg}},\n\
6125 @option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}\n\
6126 command options have been applied.\n\
6128 @cindex disabling certain registers\n\
6129 @cindex controlling register usage\n\
6130 If the usage of an entire class of registers depends on the target\n\
6131 flags, you may indicate this to GCC by using this macro to modify\n\
6132 @code{fixed_regs} and @code{call_used_regs} to 1 for each of the\n\
6133 registers in the classes which should not be used by GCC@. Also make\n\
6134 @code{define_register_constraint}s return @code{NO_REGS} for constraints\n\
6135 that shouldn't be used.\n\
6137 (However, if this class is not included in @code{GENERAL_REGS} and all\n\
6138 of the insn patterns whose constraints permit this class are\n\
6139 controlled by target switches, then GCC will automatically avoid using\n\
6140 these registers when the target switches are opposed to them.)",
6145 (stack_clash_protection_alloca_probe_range,
6146 "Some targets have an ABI defined interval for which no probing needs to be done.\n\
6147 When a probe does need to be done this same interval is used as the probe distance \
6148 up when doing stack clash protection for alloca.\n\
6149 On such targets this value can be set to override the default probing up interval.\n\
6150 Define this variable to return nonzero if such a probe range is required or zero otherwise. \
6151 Defining this hook also requires your functions which make use of alloca to have at least 8 byes\
6152 of outgoing arguments. If this is not the case the stack will be corrupted.\n\
6153 You need not define this macro if it would always have the value zero.",
6154 HOST_WIDE_INT, (void),
6155 default_stack_clash_protection_alloca_probe_range)
6158 /* Functions specific to the C family of frontends. */
6160 #define HOOK_PREFIX "TARGET_C_"
6161 HOOK_VECTOR (TARGET_C, c)
6163 /* ??? Documenting this hook requires a GFDL license grant. */
6166 "Return machine mode for non-standard constant literal suffix @var{c},\
6167 or VOIDmode if non-standard suffixes are unsupported.",
6168 machine_mode, (char c),
6169 default_mode_for_suffix)
6173 "Return a value, with the same meaning as the C99 macro\
6174 @code{FLT_EVAL_METHOD} that describes which excess precision should be\
6175 applied. @var{type} is either @code{EXCESS_PRECISION_TYPE_IMPLICIT},\
6176 @code{EXCESS_PRECISION_TYPE_FAST}, or\
6177 @code{EXCESS_PRECISION_TYPE_STANDARD}. For\
6178 @code{EXCESS_PRECISION_TYPE_IMPLICIT}, the target should return which\
6179 precision and range operations will be implictly evaluated in regardless\
6180 of the excess precision explicitly added. For\
6181 @code{EXCESS_PRECISION_TYPE_STANDARD} and\
6182 @code{EXCESS_PRECISION_TYPE_FAST}, the target should return the\
6183 explicit excess precision that should be added depending on the\
6184 value set for @option{-fexcess-precision=@r{[}standard@r{|}fast@r{]}}.\
6185 Note that unpredictable explicit excess precision does not make sense,\
6186 so a target should never return @code{FLT_EVAL_METHOD_UNPREDICTABLE}\
6187 when @var{type} is @code{EXCESS_PRECISION_TYPE_STANDARD} or\
6188 @code{EXCESS_PRECISION_TYPE_FAST}.",
6189 enum flt_eval_method, (enum excess_precision_type type),
6190 default_excess_precision)
6194 /* Functions specific to the C++ frontend. */
6196 #define HOOK_PREFIX "TARGET_CXX_"
6197 HOOK_VECTOR (TARGET_CXX, cxx)
6199 /* Return the integer type used for guard variables. */
6202 "Define this hook to override the integer type used for guard variables.\n\
6203 These are used to implement one-time construction of static objects. The\n\
6204 default is long_long_integer_type_node.",
6206 default_cxx_guard_type)
6208 /* Return true if only the low bit of the guard should be tested. */
6211 "This hook determines how guard variables are used. It should return\n\
6212 @code{false} (the default) if the first byte should be used. A return value of\n\
6213 @code{true} indicates that only the least significant bit should be used.",
6215 hook_bool_void_false)
6217 /* Returns the size of the array cookie for an array of type. */
6220 "This hook returns the size of the cookie to use when allocating an array\n\
6221 whose elements have the indicated @var{type}. Assumes that it is already\n\
6222 known that a cookie is needed. The default is\n\
6223 @code{max(sizeof (size_t), alignof(type))}, as defined in section 2.7 of the\n\
6224 IA64/Generic C++ ABI@.",
6226 default_cxx_get_cookie_size)
6228 /* Returns true if the element size should be stored in the array cookie. */
6231 "This hook should return @code{true} if the element size should be stored in\n\
6232 array cookies. The default is to return @code{false}.",
6234 hook_bool_void_false)
6236 /* Allows backends to perform additional processing when
6237 deciding if a class should be exported or imported. */
6239 (import_export_class,
6240 "If defined by a backend this hook allows the decision made to export\n\
6241 class @var{type} to be overruled. Upon entry @var{import_export}\n\
6242 will contain 1 if the class is going to be exported, @minus{}1 if it is going\n\
6243 to be imported and 0 otherwise. This function should return the\n\
6244 modified value and perform any other actions necessary to support the\n\
6245 backend's targeted operating system.",
6246 int, (tree type, int import_export), NULL)
6248 /* Returns true if constructors and destructors return "this". */
6250 (cdtor_returns_this,
6251 "This hook should return @code{true} if constructors and destructors return\n\
6252 the address of the object created/destroyed. The default is to return\n\
6255 hook_bool_void_false)
6257 /* Returns true if the key method for a class can be an inline
6258 function, so long as it is not declared inline in the class
6259 itself. Returning true is the behavior required by the Itanium C++ ABI. */
6261 (key_method_may_be_inline,
6262 "This hook returns true if the key method for a class (i.e., the method\n\
6263 which, if defined in the current translation unit, causes the virtual\n\
6264 table to be emitted) may be an inline function. Under the standard\n\
6265 Itanium C++ ABI the key method may be an inline function so long as\n\
6266 the function is not declared inline in the class definition. Under\n\
6267 some variants of the ABI, an inline function can never be the key\n\
6268 method. The default is to return @code{true}.",
6270 hook_bool_void_true)
6273 (determine_class_data_visibility,
6274 "@var{decl} is a virtual table, virtual table table, typeinfo object,\
6275 or other similar implicit class data object that will be emitted with\
6276 external linkage in this translation unit. No ELF visibility has been\
6277 explicitly specified. If the target needs to specify a visibility\
6278 other than that of the containing class, use this hook to set\
6279 @code{DECL_VISIBILITY} and @code{DECL_VISIBILITY_SPECIFIED}.",
6283 /* Returns true (the default) if virtual tables and other
6284 similar implicit class data objects are always COMDAT if they
6285 have external linkage. If this hook returns false, then
6286 class data for classes whose virtual table will be emitted in
6287 only one translation unit will not be COMDAT. */
6289 (class_data_always_comdat,
6290 "This hook returns true (the default) if virtual tables and other\n\
6291 similar implicit class data objects are always COMDAT if they have\n\
6292 external linkage. If this hook returns false, then class data for\n\
6293 classes whose virtual table will be emitted in only one translation\n\
6294 unit will not be COMDAT.",
6296 hook_bool_void_true)
6298 /* Returns true (the default) if the RTTI for the basic types,
6299 which is always defined in the C++ runtime, should be COMDAT;
6300 false if it should not be COMDAT. */
6302 (library_rtti_comdat,
6303 "This hook returns true (the default) if the RTTI information for\n\
6304 the basic types which is defined in the C++ runtime should always\n\
6305 be COMDAT, false if it should not be COMDAT.",
6307 hook_bool_void_true)
6309 /* Returns true if __aeabi_atexit should be used to register static
6313 "This hook returns true if @code{__aeabi_atexit} (as defined by the ARM EABI)\n\
6314 should be used to register static destructors when @option{-fuse-cxa-atexit}\n\
6315 is in effect. The default is to return false to use @code{__cxa_atexit}.",
6317 hook_bool_void_false)
6319 /* Returns true if target may use atexit in the same manner as
6320 __cxa_atexit to register static destructors. */
6322 (use_atexit_for_cxa_atexit,
6323 "This hook returns true if the target @code{atexit} function can be used\n\
6324 in the same manner as @code{__cxa_atexit} to register C++ static\n\
6325 destructors. This requires that @code{atexit}-registered functions in\n\
6326 shared libraries are run in the correct order when the libraries are\n\
6327 unloaded. The default is to return false.",
6329 hook_bool_void_false)
6332 (adjust_class_at_definition,
6333 "@var{type} is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has just\
6334 been defined. Use this hook to make adjustments to the class (eg, tweak\
6335 visibility or perform any other required target modifications).",
6340 (decl_mangling_context,
6341 "Return target-specific mangling context of @var{decl} or @code{NULL_TREE}.",
6342 tree, (const_tree decl),
6343 hook_tree_const_tree_null)
6345 HOOK_VECTOR_END (cxx)
6347 /* Functions and data for emulated TLS support. */
6349 #define HOOK_PREFIX "TARGET_EMUTLS_"
6350 HOOK_VECTOR (TARGET_EMUTLS, emutls)
6352 /* Name of the address and common functions. */
6355 "Contains the name of the helper function that uses a TLS control\n\
6356 object to locate a TLS instance. The default causes libgcc's\n\
6357 emulated TLS helper function to be used.",
6358 const char *, "__builtin___emutls_get_address")
6362 "Contains the name of the helper function that should be used at\n\
6363 program startup to register TLS objects that are implicitly\n\
6364 initialized to zero. If this is @code{NULL}, all TLS objects will\n\
6365 have explicit initializers. The default causes libgcc's emulated TLS\n\
6366 registration function to be used.",
6367 const char *, "__builtin___emutls_register_common")
6369 /* Prefixes for proxy variable and template. */
6372 "Contains the name of the section in which TLS control variables should\n\
6373 be placed. The default of @code{NULL} allows these to be placed in\n\
6379 "Contains the name of the section in which TLS initializers should be\n\
6380 placed. The default of @code{NULL} allows these to be placed in any\n\
6384 /* Prefixes for proxy variable and template. */
6387 "Contains the prefix to be prepended to TLS control variable names.\n\
6388 The default of @code{NULL} uses a target-specific prefix.",
6393 "Contains the prefix to be prepended to TLS initializer objects. The\n\
6394 default of @code{NULL} uses a target-specific prefix.",
6397 /* Function to generate field definitions of the proxy variable. */
6400 "Specifies a function that generates the FIELD_DECLs for a TLS control\n\
6401 object type. @var{type} is the RECORD_TYPE the fields are for and\n\
6402 @var{name} should be filled with the structure tag, if the default of\n\
6403 @code{__emutls_object} is unsuitable. The default creates a type suitable\n\
6404 for libgcc's emulated TLS function.",
6405 tree, (tree type, tree *name),
6406 default_emutls_var_fields)
6408 /* Function to initialize a proxy variable. */
6411 "Specifies a function that generates the CONSTRUCTOR to initialize a\n\
6412 TLS control object. @var{var} is the TLS control object, @var{decl}\n\
6413 is the TLS object and @var{tmpl_addr} is the address of the\n\
6414 initializer. The default initializes libgcc's emulated TLS control object.",
6415 tree, (tree var, tree decl, tree tmpl_addr),
6416 default_emutls_var_init)
6418 /* Whether we are allowed to alter the usual alignment of the
6422 "Specifies whether the alignment of TLS control variable objects is\n\
6423 fixed and should not be increased as some backends may do to optimize\n\
6424 single objects. The default is false.",
6427 /* Whether we can emit debug information for TLS vars. */
6429 (debug_form_tls_address,
6430 "Specifies whether a DWARF @code{DW_OP_form_tls_address} location descriptor\n\
6431 may be used to describe emulated TLS control objects.",
6434 HOOK_VECTOR_END (emutls)
6437 #define HOOK_PREFIX "TARGET_OPTION_"
6438 HOOK_VECTOR (TARGET_OPTION_HOOKS, target_option_hooks)
6440 /* Function to validate the attribute((target(...))) strings. If
6441 the option is validated, the hook should also fill in
6442 DECL_FUNCTION_SPECIFIC_TARGET in the function decl node. */
6445 "This hook is called to parse @code{attribute(target(\"...\"))}, which\n\
6446 allows setting target-specific options on individual functions.\n\
6447 These function-specific options may differ\n\
6448 from the options specified on the command line. The hook should return\n\
6449 @code{true} if the options are valid.\n\
6451 The hook should set the @code{DECL_FUNCTION_SPECIFIC_TARGET} field in\n\
6452 the function declaration to hold a pointer to a target-specific\n\
6453 @code{struct cl_target_option} structure.",
6454 bool, (tree fndecl, tree name, tree args, int flags),
6455 default_target_option_valid_attribute_p)
6457 /* Function to save any extra target state in the target options structure. */
6460 "This hook is called to save any additional target-specific information\n\
6461 in the @code{struct cl_target_option} structure for function-specific\n\
6462 options from the @code{struct gcc_options} structure.\n\
6463 @xref{Option file format}.",
6464 void, (struct cl_target_option *ptr, struct gcc_options *opts,
6465 struct gcc_options *opts_set), NULL)
6467 /* Function to restore any extra target state from the target options
6471 "This hook is called to restore any additional target-specific\n\
6472 information in the @code{struct cl_target_option} structure for\n\
6473 function-specific options to the @code{struct gcc_options} structure.",
6474 void, (struct gcc_options *opts, struct gcc_options *opts_set,
6475 struct cl_target_option *ptr), NULL)
6477 /* Function to update target-specific option information after being
6481 "This hook is called to update target-specific information in the\n\
6482 @code{struct cl_target_option} structure after it is streamed in from\n\
6484 void, (struct cl_target_option *ptr), NULL)
6486 /* Function to print any extra target state from the target options
6490 "This hook is called to print any additional target-specific\n\
6491 information in the @code{struct cl_target_option} structure for\n\
6492 function-specific options.",
6493 void, (FILE *file, int indent, struct cl_target_option *ptr), NULL)
6495 /* Function to parse arguments to be validated for #pragma target, and to
6496 change the state if the options are valid. If the first argument is
6497 NULL, the second argument specifies the default options to use. Return
6498 true if the options are valid, and set the current state. */
6501 "This target hook parses the options for @code{#pragma GCC target}, which\n\
6502 sets the target-specific options for functions that occur later in the\n\
6503 input stream. The options accepted should be the same as those handled by the\n\
6504 @code{TARGET_OPTION_VALID_ATTRIBUTE_P} hook.",
6505 bool, (tree args, tree pop_target),
6506 default_target_option_pragma_parse)
6508 /* Do option overrides for the target. */
6511 "Sometimes certain combinations of command options do not make sense on\n\
6512 a particular target machine. You can override the hook\n\
6513 @code{TARGET_OPTION_OVERRIDE} to take account of this. This hooks is called\n\
6514 once just after all the command options have been parsed.\n\
6516 Don't use this hook to turn on various extra optimizations for\n\
6517 @option{-O}. That is what @code{TARGET_OPTION_OPTIMIZATION} is for.\n\
6519 If you need to do something whenever the optimization level is\n\
6520 changed via the optimize attribute or pragma, see\n\
6521 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}",
6525 /* This function returns true if DECL1 and DECL2 are versions of the same
6526 function. DECL1 and DECL2 are function versions if and only if they
6527 have the same function signature and different target specific attributes,
6528 that is, they are compiled for different target machines. */
6531 "This target hook returns @code{true} if @var{DECL1} and @var{DECL2} are\n\
6532 versions of the same function. @var{DECL1} and @var{DECL2} are function\n\
6533 versions if and only if they have the same function signature and\n\
6534 different target specific attributes, that is, they are compiled for\n\
6535 different target machines.",
6536 bool, (tree decl1, tree decl2),
6537 hook_bool_tree_tree_false)
6539 /* Function to determine if one function can inline another function. */
6541 #define HOOK_PREFIX "TARGET_"
6544 "This target hook returns @code{false} if the @var{caller} function\n\
6545 cannot inline @var{callee}, based on target specific information. By\n\
6546 default, inlining is not allowed if the callee function has function\n\
6547 specific target options and the caller does not use the same options.",
6548 bool, (tree caller, tree callee),
6549 default_target_can_inline_p)
6553 "This target hook fixes function @var{fndecl} after attributes are processed. Default does nothing. On ARM, the default function's alignment is updated with the attribute target.",
6554 void, (tree fndecl),
6557 HOOK_VECTOR_END (target_option)
6559 /* For targets that need to mark extra registers as live on entry to
6560 the function, they should define this target hook and set their
6561 bits in the bitmap passed in. */
6563 (extra_live_on_entry,
6564 "Add any hard registers to @var{regs} that are live on entry to the\n\
6565 function. This hook only needs to be defined to provide registers that\n\
6566 cannot be found by examination of FUNCTION_ARG_REGNO_P, the callee saved\n\
6567 registers, STATIC_CHAIN_INCOMING_REGNUM, STATIC_CHAIN_REGNUM,\n\
6568 TARGET_STRUCT_VALUE_RTX, FRAME_POINTER_REGNUM, EH_USES,\n\
6569 FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM.",
6570 void, (bitmap regs),
6573 /* Targets should define this target hook to mark that non-callee clobbers are
6574 present in CALL_INSN_FUNCTION_USAGE for all the calls that bind to a local
6577 (call_fusage_contains_non_callee_clobbers,
6578 "Set to true if each call that binds to a local definition explicitly\n\
6579 clobbers or sets all non-fixed registers modified by performing the call.\n\
6580 That is, by the call pattern itself, or by code that might be inserted by the\n\
6581 linker (e.g.@: stubs, veneers, branch islands), but not including those\n\
6582 modifiable by the callee. The affected registers may be mentioned explicitly\n\
6583 in the call pattern, or included as clobbers in CALL_INSN_FUNCTION_USAGE.\n\
6584 The default version of this hook is set to false. The purpose of this hook\n\
6585 is to enable the fipa-ra optimization.",
6589 /* Fill in additional registers set up by prologue into a regset. */
6591 (set_up_by_prologue,
6592 "This hook should add additional registers that are computed by the prologue\
6593 to the hard regset for shrink-wrapping optimization purposes.",
6594 void, (struct hard_reg_set_container *),
6597 /* For targets that have attributes that can affect whether a
6598 function's return statements need checking. For instance a 'naked'
6599 function attribute. */
6602 "True if a function's return statements should be checked for matching the function's return type. This includes checking for falling off the end of a non-void function. Return false if no such check should be made.",
6604 hook_bool_tree_true)
6607 #define HOOK_PREFIX "TARGET_SHRINK_WRAP_"
6608 HOOK_VECTOR (TARGET_SHRINK_WRAP_HOOKS, shrink_wrap)
6611 (get_separate_components,
6612 "This hook should return an @code{sbitmap} with the bits set for those\n\
6613 components that can be separately shrink-wrapped in the current function.\n\
6614 Return @code{NULL} if the current function should not get any separate\n\
6616 Don't define this hook if it would always return @code{NULL}.\n\
6617 If it is defined, the other hooks in this group have to be defined as well.",
6623 "This hook should return an @code{sbitmap} with the bits set for those\n\
6624 components where either the prologue component has to be executed before\n\
6625 the @code{basic_block}, or the epilogue component after it, or both.",
6626 sbitmap, (basic_block),
6630 (disqualify_components,
6631 "This hook should clear the bits in the @var{components} bitmap for those\n\
6632 components in @var{edge_components} that the target cannot handle on edge\n\
6633 @var{e}, where @var{is_prologue} says if this is for a prologue or an\n\
6635 void, (sbitmap components, edge e, sbitmap edge_components, bool is_prologue),
6639 (emit_prologue_components,
6640 "Emit prologue insns for the components indicated by the parameter.",
6645 (emit_epilogue_components,
6646 "Emit epilogue insns for the components indicated by the parameter.",
6651 (set_handled_components,
6652 "Mark the components in the parameter as handled, so that the\n\
6653 @code{prologue} and @code{epilogue} named patterns know to ignore those\n\
6654 components. The target code should not hang on to the @code{sbitmap}, it\n\
6655 will be deleted after this call.",
6659 HOOK_VECTOR_END (shrink_wrap)
6661 #define HOOK_PREFIX "TARGET_"
6663 /* Determine the type of unwind info to emit for debugging. */
6666 "This hook defines the mechanism that will be used for describing frame\n\
6667 unwind information to the debugger. Normally the hook will return\n\
6668 @code{UI_DWARF2} if DWARF 2 debug information is enabled, and\n\
6669 return @code{UI_NONE} otherwise.\n\
6671 A target may return @code{UI_DWARF2} even when DWARF 2 debug information\n\
6672 is disabled in order to always output DWARF 2 frame information.\n\
6674 A target may return @code{UI_TARGET} if it has ABI specified unwind tables.\n\
6675 This will suppress generation of the normal debug frame unwind information.",
6676 enum unwind_info_type, (void),
6677 default_debug_unwind_info)
6680 (reset_location_view, "\
6681 This hook, if defined, enables -ginternal-reset-location-views, and\n\
6682 uses its result to override cases in which the estimated min insn\n\
6683 length might be nonzero even when a PC advance (i.e., a view reset)\n\
6684 cannot be taken for granted.\n\
6686 If the hook is defined, it must return a positive value to indicate\n\
6687 the insn definitely advances the PC, and so the view number can be\n\
6688 safely assumed to be reset; a negative value to mean the insn\n\
6689 definitely does not advance the PC, and os the view number must not\n\
6690 be reset; or zero to decide based on the estimated insn length.\n\
6692 If insn length is to be regarded as reliable, set the hook to\n\
6693 @code{hook_int_rtx_insn_0}.",
6694 int, (rtx_insn *), NULL)
6696 /* The code parameter should be of type enum rtx_code but this is not
6697 defined at this time. */
6699 (canonicalize_comparison,
6700 "On some machines not all possible comparisons are defined, but you can\n\
6701 convert an invalid comparison into a valid one. For example, the Alpha\n\
6702 does not have a @code{GT} comparison, but you can use an @code{LT}\n\
6703 comparison instead and swap the order of the operands.\n\
6705 On such machines, implement this hook to do any required conversions.\n\
6706 @var{code} is the initial comparison code and @var{op0} and @var{op1}\n\
6707 are the left and right operands of the comparison, respectively. If\n\
6708 @var{op0_preserve_value} is @code{true} the implementation is not\n\
6709 allowed to change the value of @var{op0} since the value might be used\n\
6710 in RTXs which aren't comparisons. E.g. the implementation is not\n\
6711 allowed to swap operands in that case.\n\
6713 GCC will not assume that the comparison resulting from this macro is\n\
6714 valid but will see if the resulting insn matches a pattern in the\n\
6717 You need not to implement this hook if it would never change the\n\
6718 comparison code or operands.",
6719 void, (int *code, rtx *op0, rtx *op1, bool op0_preserve_value),
6720 default_canonicalize_comparison)
6723 (min_arithmetic_precision,
6724 "On some RISC architectures with 64-bit registers, the processor also\n\
6725 maintains 32-bit condition codes that make it possible to do real 32-bit\n\
6726 arithmetic, although the operations are performed on the full registers.\n\
6728 On such architectures, defining this hook to 32 tells the compiler to try\n\
6729 using 32-bit arithmetical operations setting the condition codes instead\n\
6730 of doing full 64-bit arithmetic.\n\
6732 More generally, define this hook on RISC architectures if you want the\n\
6733 compiler to try using arithmetical operations setting the condition codes\n\
6734 with a precision lower than the word precision.\n\
6736 You need not define this hook if @code{WORD_REGISTER_OPERATIONS} is not\n\
6738 unsigned int, (void), default_min_arithmetic_precision)
6741 (atomic_test_and_set_trueval,
6742 "This value should be set if the result written by\
6743 @code{atomic_test_and_set} is not exactly 1, i.e.@: the\
6744 @code{bool} @code{true}.",
6747 /* Return an unsigned int representing the alignment (in bits) of the atomic
6748 type which maps to machine MODE. This allows alignment to be overridden
6751 (atomic_align_for_mode,
6752 "If defined, this function returns an appropriate alignment in bits for an\
6753 atomic object of machine_mode @var{mode}. If 0 is returned then the\
6754 default alignment for the specified mode is used. ",
6755 unsigned int, (machine_mode mode),
6759 (atomic_assign_expand_fenv,
6760 "ISO C11 requires atomic compound assignments that may raise floating-point\
6761 exceptions to raise exceptions corresponding to the arithmetic operation\
6762 whose result was successfully stored in a compare-and-exchange sequence. \
6763 This requires code equivalent to calls to @code{feholdexcept},\
6764 @code{feclearexcept} and @code{feupdateenv} to be generated at\
6765 appropriate points in the compare-and-exchange sequence. This hook should\
6766 set @code{*@var{hold}} to an expression equivalent to the call to\
6767 @code{feholdexcept}, @code{*@var{clear}} to an expression equivalent to\
6768 the call to @code{feclearexcept} and @code{*@var{update}} to an expression\
6769 equivalent to the call to @code{feupdateenv}. The three expressions are\
6770 @code{NULL_TREE} on entry to the hook and may be left as @code{NULL_TREE}\
6771 if no code is required in a particular place. The default implementation\
6772 leaves all three expressions as @code{NULL_TREE}. The\
6773 @code{__atomic_feraiseexcept} function from @code{libatomic} may be of use\
6774 as part of the code generated in @code{*@var{update}}.",
6775 void, (tree *hold, tree *clear, tree *update),
6776 default_atomic_assign_expand_fenv)
6778 /* Leave the boolean fields at the end. */
6780 /* True if we can create zeroed data by switching to a BSS section
6781 and then using ASM_OUTPUT_SKIP to allocate the space. */
6783 (have_switchable_bss_sections,
6784 "This flag is true if we can create zeroed data by switching to a BSS\n\
6785 section and then using @code{ASM_OUTPUT_SKIP} to allocate the space.\n\
6786 This is true on most ELF targets.",
6789 /* True if "native" constructors and destructors are supported,
6790 false if we're using collect2 for the job. */
6793 "This value is true if the target supports some ``native'' method of\n\
6794 collecting constructors and destructors to be run at startup and exit.\n\
6795 It is false if we must use @command{collect2}.",
6798 /* True if thread-local storage is supported. */
6801 "Contains the value true if the target supports thread-local storage.\n\
6802 The default value is false.",
6805 /* True if a small readonly data section is supported. */
6807 (have_srodata_section,
6808 "Contains the value true if the target places read-only\n\
6809 ``small data'' into a separate section. The default value is false.",
6812 /* True if EH frame info sections should be zero-terminated. */
6814 (terminate_dw2_eh_frame_info,
6815 "Contains the value true if the target should add a zero word onto the\n\
6816 end of a Dwarf-2 frame info section when used for exception handling.\n\
6817 Default value is false if @code{EH_FRAME_SECTION_NAME} is defined, and\n\
6821 /* True if #NO_APP should be emitted at the beginning of assembly output. */
6823 (asm_file_start_app_off,
6824 "If this flag is true, the text of the macro @code{ASM_APP_OFF} will be\n\
6825 printed as the very first line in the assembly file, unless\n\
6826 @option{-fverbose-asm} is in effect. (If that macro has been defined\n\
6827 to the empty string, this variable has no effect.) With the normal\n\
6828 definition of @code{ASM_APP_OFF}, the effect is to notify the GNU\n\
6829 assembler that it need not bother stripping comments or extra\n\
6830 whitespace from its input. This allows it to work a bit faster.\n\
6832 The default is false. You should not set it to true unless you have\n\
6833 verified that your port does not generate any extra whitespace or\n\
6834 comments that will cause GAS to issue errors in NO_APP mode.",
6837 /* True if output_file_directive should be called for main_input_filename
6838 at the beginning of assembly output. */
6840 (asm_file_start_file_directive,
6841 "If this flag is true, @code{output_file_directive} will be called\n\
6842 for the primary source file, immediately after printing\n\
6843 @code{ASM_APP_OFF} (if that is enabled). Most ELF assemblers expect\n\
6844 this to be done. The default is false.",
6847 /* Returns true if we should generate exception tables for use with the
6848 ARM EABI. The effects the encoding of function exception specifications. */
6851 "This flag should be set to @code{true} on targets that use an ARM EABI\n\
6852 based unwinding library, and @code{false} on other targets. This effects\n\
6853 the format of unwinding tables, and how the unwinder in entered after\n\
6854 running a cleanup. The default is @code{false}.",
6858 (want_debug_pub_sections,
6859 "True if the @code{.debug_pubtypes} and @code{.debug_pubnames} sections\
6860 should be emitted. These sections are not used on most platforms, and\
6861 in particular GDB does not use them.",
6865 (delay_sched2, "True if sched2 is not to be run at its normal place.\n\
6866 This usually means it will be run as part of machine-specific reorg.",
6870 (delay_vartrack, "True if vartrack is not to be run at its normal place.\n\
6871 This usually means it will be run as part of machine-specific reorg.",
6875 (no_register_allocation, "True if register allocation and the passes\n\
6876 following it should not be run. Usually true only for virtual assembler\n\
6880 /* Leave the boolean fields at the end. */
6882 /* Functions related to mode switching. */
6884 #define HOOK_PREFIX "TARGET_MODE_"
6885 HOOK_VECTOR (TARGET_TOGGLE_, mode_switching)
6889 "Generate one or more insns to set @var{entity} to @var{mode}. @var{hard_reg_live} is the set of hard registers live at the point where the insn(s) are to be inserted. @var{prev_moxde} indicates the mode to switch from. Sets of a lower numbered entity will be emitted before sets of a higher numbered entity to a mode of the same or lower priority.",
6890 void, (int entity, int mode, int prev_mode, HARD_REG_SET regs_live), NULL)
6894 "@var{entity} is an integer specifying a mode-switched entity. If @code{OPTIMIZE_MODE_SWITCHING} is defined, you must define this macro to return an integer value not larger than the corresponding element in @code{NUM_MODES_FOR_MODE_SWITCHING}, to denote the mode that @var{entity} must be switched into prior to the execution of @var{insn}.",
6895 int, (int entity, rtx_insn *insn), NULL)
6899 "@var{entity} is an integer specifying a mode-switched entity. If this macro is defined, it is evaluated for every @var{insn} during mode switching. It determines the mode that an insn results in (if different from the incoming mode).",
6900 int, (int entity, int mode, rtx_insn *insn), NULL)
6904 "If this macro is defined, it is evaluated for every @var{entity} that needs mode switching. It should evaluate to an integer, which is a mode that @var{entity} is assumed to be switched to at function entry. If @code{TARGET_MODE_ENTRY} is defined then @code{TARGET_MODE_EXIT} must be defined.",
6905 int, (int entity), NULL)
6909 "If this macro is defined, it is evaluated for every @var{entity} that needs mode switching. It should evaluate to an integer, which is a mode that @var{entity} is assumed to be switched to at function exit. If @code{TARGET_MODE_EXIT} is defined then @code{TARGET_MODE_ENTRY} must be defined.",
6910 int, (int entity), NULL)
6914 "This macro specifies the order in which modes for @var{entity} are processed. 0 is the highest priority, @code{NUM_MODES_FOR_MODE_SWITCHING[@var{entity}] - 1} the lowest. The value of the macro should be an integer designating a mode for @var{entity}. For any fixed @var{entity}, @code{mode_priority} (@var{entity}, @var{n}) shall be a bijection in 0 @dots{} @code{num_modes_for_mode_switching[@var{entity}] - 1}.",
6915 int, (int entity, int n), NULL)
6917 HOOK_VECTOR_END (mode_switching)
6920 #define HOOK_PREFIX "TARGET_MEMTAG_"
6921 HOOK_VECTOR (TARGET_MEMTAG_, memtag)
6925 "True if the backend architecture naturally supports ignoring some region\n\
6926 of pointers. This feature means that @option{-fsanitize=hwaddress} can\n\
6929 At preset, this feature does not support address spaces. It also requires\n\
6930 @code{Pmode} to be the same as @code{ptr_mode}.",
6931 bool, (), default_memtag_can_tag_addresses)
6935 "Return the size of a tag (in bits) for this platform.\n\
6937 The default returns 8.",
6938 uint8_t, (), default_memtag_tag_size)
6942 "Return the size in real memory that each byte in shadow memory refers to.\n\
6943 I.e. if a variable is @var{X} bytes long in memory, then this hook should\n\
6944 return the value @var{Y} such that the tag in shadow memory spans\n\
6945 @var{X}/@var{Y} bytes.\n\
6947 Most variables will need to be aligned to this amount since two variables\n\
6948 that are neighbors in memory and share a tag granule would need to share\n\
6951 The default returns 16.",
6952 uint8_t, (), default_memtag_granule_size)
6956 "Return an RTX representing the value of @var{untagged} but with a\n\
6957 (possibly) random tag in it.\n\
6958 Put that value into @var{target} if it is convenient to do so.\n\
6959 This function is used to generate a tagged base for the current stack frame.",
6960 rtx, (rtx untagged, rtx target), default_memtag_insert_random_tag)
6964 "Return an RTX that represents the result of adding @var{addr_offset} to\n\
6965 the address in pointer @var{base} and @var{tag_offset} to the tag in pointer\n\
6967 The resulting RTX must either be a valid memory address or be able to get\n\
6968 put into an operand with @code{force_operand}.\n\
6970 Unlike other memtag hooks, this must return an expression and not emit any\n\
6972 rtx, (rtx base, poly_int64 addr_offset, uint8_t tag_offset),
6973 default_memtag_add_tag)
6977 "Return an RTX representing @var{untagged_base} but with the tag @var{tag}.\n\
6978 Try and store this in @var{target} if convenient.\n\
6979 @var{untagged_base} is required to have a zero tag when this hook is called.\n\
6980 The default of this hook is to set the top byte of @var{untagged_base} to\n\
6982 rtx, (rtx untagged_base, rtx tag, rtx target), default_memtag_set_tag)
6986 "Return an RTX representing the tag stored in @var{tagged_pointer}.\n\
6987 Store the result in @var{target} if it is convenient.\n\
6988 The default represents the top byte of the original pointer.",
6989 rtx, (rtx tagged_pointer, rtx target), default_memtag_extract_tag)
6993 "Return an RTX representing @var{tagged_pointer} with its tag set to zero.\n\
6994 Store the result in @var{target} if convenient.\n\
6995 The default clears the top byte of the original pointer.",
6996 rtx, (rtx tagged_pointer, rtx target), default_memtag_untagged_pointer)
6998 HOOK_VECTOR_END (memtag)
7000 #define HOOK_PREFIX "TARGET_"
7002 #define DEF_TARGET_INSN(NAME, PROTO) \
7003 DEFHOOK_UNDOC (have_##NAME, "", bool, (void), false)
7004 #include "target-insns.def"
7005 #undef DEF_TARGET_INSN
7007 #define DEF_TARGET_INSN(NAME, PROTO) \
7008 DEFHOOK_UNDOC (gen_##NAME, "", rtx_insn *, PROTO, NULL)
7009 #include "target-insns.def"
7010 #undef DEF_TARGET_INSN
7012 #define DEF_TARGET_INSN(NAME, PROTO) \
7013 DEFHOOKPOD (code_for_##NAME, "*", enum insn_code, CODE_FOR_nothing)
7014 #include "target-insns.def"
7015 #undef DEF_TARGET_INSN
7018 (run_target_selftests,
7019 "If selftests are enabled, run any selftests for this target.",
7023 /* Close the 'struct gcc_target' definition. */
7024 HOOK_VECTOR_END (C90_EMPTY_HACK)