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)
1729 HOOK_VECTOR_END (goacc)
1731 /* Functions relating to vectorization. */
1733 #define HOOK_PREFIX "TARGET_VECTORIZE_"
1734 HOOK_VECTOR (TARGET_VECTORIZE, vectorize)
1736 /* The following member value is a pointer to a function called
1737 by the vectorizer, and return the decl of the target builtin
1740 (builtin_mask_for_load,
1741 "This hook should return the DECL of a function @var{f} that given an\n\
1742 address @var{addr} as an argument returns a mask @var{m} that can be\n\
1743 used to extract from two vectors the relevant data that resides in\n\
1744 @var{addr} in case @var{addr} is not properly aligned.\n\
1746 The autovectorizer, when vectorizing a load operation from an address\n\
1747 @var{addr} that may be unaligned, will generate two vector loads from\n\
1748 the two aligned addresses around @var{addr}. It then generates a\n\
1749 @code{REALIGN_LOAD} operation to extract the relevant data from the\n\
1750 two loaded vectors. The first two arguments to @code{REALIGN_LOAD},\n\
1751 @var{v1} and @var{v2}, are the two vectors, each of size @var{VS}, and\n\
1752 the third argument, @var{OFF}, defines how the data will be extracted\n\
1753 from these two vectors: if @var{OFF} is 0, then the returned vector is\n\
1754 @var{v2}; otherwise, the returned vector is composed from the last\n\
1755 @var{VS}-@var{OFF} elements of @var{v1} concatenated to the first\n\
1756 @var{OFF} elements of @var{v2}.\n\
1758 If this hook is defined, the autovectorizer will generate a call\n\
1759 to @var{f} (using the DECL tree that this hook returns) and will\n\
1760 use the return value of @var{f} as the argument @var{OFF} to\n\
1761 @code{REALIGN_LOAD}. Therefore, the mask @var{m} returned by @var{f}\n\
1762 should comply with the semantics expected by @code{REALIGN_LOAD}\n\
1764 If this hook is not defined, then @var{addr} will be used as\n\
1765 the argument @var{OFF} to @code{REALIGN_LOAD}, in which case the low\n\
1766 log2(@var{VS}) @minus{} 1 bits of @var{addr} will be considered.",
1769 /* Returns a built-in function that realizes the vectorized version of
1770 a target-independent function, or NULL_TREE if not available. */
1772 (builtin_vectorized_function,
1773 "This hook should return the decl of a function that implements the\n\
1774 vectorized variant of the function with the @code{combined_fn} code\n\
1775 @var{code} or @code{NULL_TREE} if such a function is not available.\n\
1776 The return type of the vectorized function shall be of vector type\n\
1777 @var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1778 tree, (unsigned code, tree vec_type_out, tree vec_type_in),
1779 default_builtin_vectorized_function)
1781 /* Returns a built-in function that realizes the vectorized version of
1782 a target-specific function, or NULL_TREE if not available. */
1784 (builtin_md_vectorized_function,
1785 "This hook should return the decl of a function that implements the\n\
1786 vectorized variant of target built-in function @code{fndecl}. The\n\
1787 return type of the vectorized function shall be of vector type\n\
1788 @var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1789 tree, (tree fndecl, tree vec_type_out, tree vec_type_in),
1790 default_builtin_md_vectorized_function)
1792 /* Cost of different vector/scalar statements in vectorization cost
1793 model. In case of misaligned vector loads and stores the cost depends
1794 on the data type and misalignment value. */
1796 (builtin_vectorization_cost,
1797 "Returns cost of different scalar or vector statements for vectorization cost model.\n\
1798 For vector memory operations the cost may depend on type (@var{vectype}) and\n\
1799 misalignment value (@var{misalign}).",
1800 int, (enum vect_cost_for_stmt type_of_cost, tree vectype, int misalign),
1801 default_builtin_vectorization_cost)
1804 (preferred_vector_alignment,
1805 "This hook returns the preferred alignment in bits for accesses to\n\
1806 vectors of type @var{type} in vectorized code. This might be less than\n\
1807 or greater than the ABI-defined value returned by\n\
1808 @code{TARGET_VECTOR_ALIGNMENT}. It can be equal to the alignment of\n\
1809 a single element, in which case the vectorizer will not try to optimize\n\
1812 The default hook returns @code{TYPE_ALIGN (@var{type})}, which is\n\
1813 correct for most targets.",
1814 poly_uint64, (const_tree type),
1815 default_preferred_vector_alignment)
1817 /* Return true if vector alignment is reachable (by peeling N
1818 iterations) for the given scalar type. */
1820 (vector_alignment_reachable,
1821 "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.",
1822 bool, (const_tree type, bool is_packed),
1823 default_builtin_vector_alignment_reachable)
1827 "This hook is used to test whether the target can permute up to two\n\
1828 vectors of mode @var{mode} using the permutation vector @code{sel}, and\n\
1829 also to emit such a permutation. In the former case @var{in0}, @var{in1}\n\
1830 and @var{out} are all null. In the latter case @var{in0} and @var{in1} are\n\
1831 the source vectors and @var{out} is the destination vector; all three are\n\
1832 registers of mode @var{mode}. @var{in1} is the same as @var{in0} if\n\
1833 @var{sel} describes a permutation on one vector instead of two.\n\
1835 Return true if the operation is possible, emitting instructions for it\n\
1836 if rtxes are provided.\n\
1838 @cindex @code{vec_perm@var{m}} instruction pattern\n\
1839 If the hook returns false for a mode with multibyte elements, GCC will\n\
1840 try the equivalent byte operation. If that also fails, it will try forcing\n\
1841 the selector into a register and using the @var{vec_perm@var{mode}}\n\
1842 instruction pattern. There is no need for the hook to handle these two\n\
1843 implementation approaches itself.",
1844 bool, (machine_mode mode, rtx output, rtx in0, rtx in1,
1845 const vec_perm_indices &sel),
1848 /* Return true if the target supports misaligned store/load of a
1849 specific factor denoted in the third parameter. The last parameter
1850 is true if the access is defined in a packed struct. */
1852 (support_vector_misalignment,
1853 "This hook should return true if the target supports misaligned vector\n\
1854 store/load of a specific factor denoted in the @var{misalignment}\n\
1855 parameter. The vector store/load should be of machine mode @var{mode} and\n\
1856 the elements in the vectors should be of type @var{type}. @var{is_packed}\n\
1857 parameter is true if the memory access is defined in a packed struct.",
1859 (machine_mode mode, const_tree type, int misalignment, bool is_packed),
1860 default_builtin_support_vector_misalignment)
1862 /* Returns the preferred mode for SIMD operations for the specified
1865 (preferred_simd_mode,
1866 "This hook should return the preferred mode for vectorizing scalar\n\
1867 mode @var{mode}. The default is\n\
1868 equal to @code{word_mode}, because the vectorizer can do some\n\
1869 transformations even in absence of specialized @acronym{SIMD} hardware.",
1872 default_preferred_simd_mode)
1874 /* Returns the preferred mode for splitting SIMD reductions to. */
1877 "This hook should return the preferred mode to split the final reduction\n\
1878 step on @var{mode} to. The reduction is then carried out reducing upper\n\
1879 against lower halves of vectors recursively until the specified mode is\n\
1880 reached. The default is @var{mode} which means no splitting.",
1883 default_split_reduction)
1885 /* Returns a mask of vector sizes to iterate over when auto-vectorizing
1886 after processing the preferred one derived from preferred_simd_mode. */
1888 (autovectorize_vector_modes,
1889 "If using the mode returned by @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE}\n\
1890 is not the only approach worth considering, this hook should add one mode to\n\
1891 @var{modes} for each useful alternative approach. These modes are then\n\
1892 passed to @code{TARGET_VECTORIZE_RELATED_MODE} to obtain the vector mode\n\
1893 for a given element mode.\n\
1895 The modes returned in @var{modes} should use the smallest element mode\n\
1896 possible for the vectorization approach that they represent, preferring\n\
1897 integer modes over floating-poing modes in the event of a tie. The first\n\
1898 mode should be the @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE} for its\n\
1901 If @var{all} is true, add suitable vector modes even when they are generally\n\
1902 not expected to be worthwhile.\n\
1904 The hook returns a bitmask of flags that control how the modes in\n\
1905 @var{modes} are used. The flags are:\n\
1907 @item VECT_COMPARE_COSTS\n\
1908 Tells the loop vectorizer to try all the provided modes and pick the one\n\
1909 with the lowest cost. By default the vectorizer will choose the first\n\
1913 The hook does not need to do anything if the vector returned by\n\
1914 @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE} is the only one relevant\n\
1915 for autovectorization. The default implementation adds no modes and\n\
1918 (vector_modes *modes, bool all),
1919 default_autovectorize_vector_modes)
1923 "If a piece of code is using vector mode @var{vector_mode} and also wants\n\
1924 to operate on elements of mode @var{element_mode}, return the vector mode\n\
1925 it should use for those elements. If @var{nunits} is nonzero, ensure that\n\
1926 the mode has exactly @var{nunits} elements, otherwise pick whichever vector\n\
1927 size pairs the most naturally with @var{vector_mode}. Return an empty\n\
1928 @code{opt_machine_mode} if there is no supported vector mode with the\n\
1929 required properties.\n\
1931 There is no prescribed way of handling the case in which @var{nunits}\n\
1932 is zero. One common choice is to pick a vector mode with the same size\n\
1933 as @var{vector_mode}; this is the natural choice if the target has a\n\
1934 fixed vector size. Another option is to choose a vector mode with the\n\
1935 same number of elements as @var{vector_mode}; this is the natural choice\n\
1936 if the target has a fixed number of elements. Alternatively, the hook\n\
1937 might choose a middle ground, such as trying to keep the number of\n\
1938 elements as similar as possible while applying maximum and minimum\n\
1941 The default implementation uses @code{mode_for_vector} to find the\n\
1942 requested mode, returning a mode with the same size as @var{vector_mode}\n\
1943 when @var{nunits} is zero. This is the correct behavior for most targets.",
1945 (machine_mode vector_mode, scalar_mode element_mode, poly_uint64 nunits),
1946 default_vectorize_related_mode)
1948 /* Function to get a target mode for a vector mask. */
1951 "Return the mode to use for a vector mask that holds one boolean\n\
1952 result for each element of vector mode @var{mode}. The returned mask mode\n\
1953 can be a vector of integers (class @code{MODE_VECTOR_INT}), a vector of\n\
1954 booleans (class @code{MODE_VECTOR_BOOL}) or a scalar integer (class\n\
1955 @code{MODE_INT}). Return an empty @code{opt_machine_mode} if no such\n\
1956 mask mode exists.\n\
1958 The default implementation returns a @code{MODE_VECTOR_INT} with the\n\
1959 same size and number of elements as @var{mode}, if such a mode exists.",
1961 (machine_mode mode),
1962 default_get_mask_mode)
1964 /* Function to say whether a masked operation is expensive when the
1965 mask is all zeros. */
1967 (empty_mask_is_expensive,
1968 "This hook returns true if masked internal function @var{ifn} (really of\n\
1969 type @code{internal_fn}) should be considered expensive when the mask is\n\
1970 all zeros. GCC can then try to branch around the instruction instead.",
1973 default_empty_mask_is_expensive)
1975 /* Target builtin that implements vector gather operation. */
1978 "Target builtin that implements vector gather operation. @var{mem_vectype}\n\
1979 is the vector type of the load and @var{index_type} is scalar type of\n\
1980 the index, scaled by @var{scale}.\n\
1981 The default is @code{NULL_TREE} which means to not vectorize gather\n\
1984 (const_tree mem_vectype, const_tree index_type, int scale),
1987 /* Target builtin that implements vector scatter operation. */
1990 "Target builtin that implements vector scatter operation. @var{vectype}\n\
1991 is the vector type of the store and @var{index_type} is scalar type of\n\
1992 the index, scaled by @var{scale}.\n\
1993 The default is @code{NULL_TREE} which means to not vectorize scatter\n\
1996 (const_tree vectype, const_tree index_type, int scale),
1999 /* Target function to initialize the cost model for a loop or block. */
2002 "This hook should initialize target-specific data structures in preparation "
2003 "for modeling the costs of vectorizing a loop or basic block. The default "
2004 "allocates three unsigned integers for accumulating costs for the prologue, "
2005 "body, and epilogue of the loop or basic block. If @var{loop_info} is "
2006 "non-NULL, it identifies the loop being vectorized; otherwise a single block "
2007 "is being vectorized.",
2009 (class loop *loop_info),
2012 /* Target function to record N statements of the given kind using the
2013 given vector type within the cost model data for the current loop or
2017 "This hook should update the target-specific @var{data} in response to "
2018 "adding @var{count} copies of the given @var{kind} of statement to a "
2019 "loop or basic block. The default adds the builtin vectorizer cost for "
2020 "the copies of the statement to the accumulator specified by @var{where}, "
2021 "(the prologue, body, or epilogue) and returns the amount added. The "
2022 "return value should be viewed as a tentative cost that may later be "
2025 (class vec_info *, void *data, int count, enum vect_cost_for_stmt kind,
2026 class _stmt_vec_info *stmt_info, tree vectype, int misalign,
2027 enum vect_cost_model_location where),
2028 default_add_stmt_cost)
2030 /* Target function to calculate the total cost of the current vectorized
2034 "This hook should complete calculations of the cost of vectorizing a loop "
2035 "or basic block based on @var{data}, and return the prologue, body, and "
2036 "epilogue costs as unsigned integers. The default returns the value of "
2037 "the three accumulators.",
2039 (void *data, unsigned *prologue_cost, unsigned *body_cost,
2040 unsigned *epilogue_cost),
2041 default_finish_cost)
2043 /* Function to delete target-specific cost modeling data. */
2046 "This hook should release @var{data} and any related data structures "
2047 "allocated by TARGET_VECTORIZE_INIT_COST. The default releases the "
2051 default_destroy_cost_data)
2053 HOOK_VECTOR_END (vectorize)
2056 #define HOOK_PREFIX "TARGET_"
2059 (preferred_else_value,
2060 "This hook returns the target's preferred final argument for a call\n\
2061 to conditional internal function @var{ifn} (really of type\n\
2062 @code{internal_fn}). @var{type} specifies the return type of the\n\
2063 function and @var{ops} are the operands to the conditional operation,\n\
2064 of which there are @var{nops}.\n\
2066 For example, if @var{ifn} is @code{IFN_COND_ADD}, the hook returns\n\
2067 a value of type @var{type} that should be used when @samp{@var{ops}[0]}\n\
2068 and @samp{@var{ops}[1]} are conditionally added together.\n\
2070 This hook is only relevant if the target supports conditional patterns\n\
2071 like @code{cond_add@var{m}}. The default implementation returns a zero\n\
2072 constant of type @var{type}.",
2074 (unsigned ifn, tree type, unsigned nops, tree *ops),
2075 default_preferred_else_value)
2078 (record_offload_symbol,
2079 "Used when offloaded functions are seen in the compilation unit and no named\n\
2080 sections are available. It is called once for each symbol that must be\n\
2081 recorded in the offload function and variable table.",
2086 (absolute_biggest_alignment,
2087 "If defined, this target hook specifies the absolute biggest alignment\n\
2088 that a type or variable can have on this machine, otherwise,\n\
2089 @code{BIGGEST_ALIGNMENT} is used.",
2090 HOST_WIDE_INT, BIGGEST_ALIGNMENT)
2092 /* Allow target specific overriding of option settings after options have
2093 been changed by an attribute or pragma or when it is reset at the
2094 end of the code affected by an attribute or pragma. */
2096 (override_options_after_change,
2097 "This target function is similar to the hook @code{TARGET_OPTION_OVERRIDE}\n\
2098 but is called when the optimize level is changed via an attribute or\n\
2099 pragma or when it is reset at the end of the code affected by the\n\
2100 attribute or pragma. It is not called at the beginning of compilation\n\
2101 when @code{TARGET_OPTION_OVERRIDE} is called so if you want to perform these\n\
2102 actions then, you should have @code{TARGET_OPTION_OVERRIDE} call\n\
2103 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}.",
2109 "Used when writing out the list of options into an LTO file. It should\n\
2110 translate any relevant target-specific options (such as the ABI in use)\n\
2111 into one of the @option{-foffload} options that exist as a common interface\n\
2112 to express such options. It should return a string containing these options,\n\
2113 separated by spaces, which the caller will free.\n",
2114 char *, (void), hook_charptr_void_null)
2117 (eh_return_filter_mode,
2118 "Return machine mode for filter value.",
2119 scalar_int_mode, (void),
2120 default_eh_return_filter_mode)
2122 /* Return machine mode for libgcc expanded cmp instructions. */
2124 (libgcc_cmp_return_mode,
2125 "This target hook should return the mode to be used for the return value\n\
2126 of compare instructions expanded to libgcc calls. If not defined\n\
2127 @code{word_mode} is returned which is the right choice for a majority of\n\
2129 scalar_int_mode, (void),
2130 default_libgcc_cmp_return_mode)
2132 /* Return machine mode for libgcc expanded shift instructions. */
2134 (libgcc_shift_count_mode,
2135 "This target hook should return the mode to be used for the shift count operand\n\
2136 of shift instructions expanded to libgcc calls. If not defined\n\
2137 @code{word_mode} is returned which is the right choice for a majority of\n\
2139 scalar_int_mode, (void),
2140 default_libgcc_shift_count_mode)
2142 /* Return machine mode to be used for _Unwind_Word type. */
2145 "Return machine mode to be used for @code{_Unwind_Word} type.\n\
2146 The default is to use @code{word_mode}.",
2147 scalar_int_mode, (void),
2148 default_unwind_word_mode)
2150 /* Given two decls, merge their attributes and return the result. */
2152 (merge_decl_attributes,
2153 "Define this target hook if the merging of decl attributes needs special\n\
2154 handling. If defined, the result is a list of the combined\n\
2155 @code{DECL_ATTRIBUTES} of @var{olddecl} and @var{newdecl}.\n\
2156 @var{newdecl} is a duplicate declaration of @var{olddecl}. Examples of\n\
2157 when this is needed are when one attribute overrides another, or when an\n\
2158 attribute is nullified by a subsequent definition. This function may\n\
2159 call @code{merge_attributes} to handle machine-independent merging.\n\
2161 @findex TARGET_DLLIMPORT_DECL_ATTRIBUTES\n\
2162 If the only target-specific handling you require is @samp{dllimport}\n\
2163 for Microsoft Windows targets, you should define the macro\n\
2164 @code{TARGET_DLLIMPORT_DECL_ATTRIBUTES} to @code{1}. The compiler\n\
2165 will then define a function called\n\
2166 @code{merge_dllimport_decl_attributes} which can then be defined as\n\
2167 the expansion of @code{TARGET_MERGE_DECL_ATTRIBUTES}. You can also\n\
2168 add @code{handle_dll_attribute} in the attribute table for your port\n\
2169 to perform initial processing of the @samp{dllimport} and\n\
2170 @samp{dllexport} attributes. This is done in @file{i386/cygwin.h} and\n\
2171 @file{i386/i386.c}, for example.",
2172 tree, (tree olddecl, tree newdecl),
2173 merge_decl_attributes)
2175 /* Given two types, merge their attributes and return the result. */
2177 (merge_type_attributes,
2178 "Define this target hook if the merging of type attributes needs special\n\
2179 handling. If defined, the result is a list of the combined\n\
2180 @code{TYPE_ATTRIBUTES} of @var{type1} and @var{type2}. It is assumed\n\
2181 that @code{comptypes} has already been called and returned 1. This\n\
2182 function may call @code{merge_attributes} to handle machine-independent\n\
2184 tree, (tree type1, tree type2),
2185 merge_type_attributes)
2187 /* Table of machine attributes and functions to handle them.
2191 "If defined, this target hook points to an array of @samp{struct\n\
2192 attribute_spec} (defined in @file{tree-core.h}) specifying the machine\n\
2193 specific attributes for this target and some of the restrictions on the\n\
2194 entities to which these attributes are applied and the arguments they\n\
2196 const struct attribute_spec *, NULL)
2198 /* Return true iff attribute NAME expects a plain identifier as its first
2201 (attribute_takes_identifier_p,
2202 "If defined, this target hook is a function which returns true if the\n\
2203 machine-specific attribute named @var{name} expects an identifier\n\
2204 given as its first argument to be passed on as a plain identifier, not\n\
2205 subjected to name lookup. If this is not defined, the default is\n\
2206 false for all machine-specific attributes.",
2207 bool, (const_tree name),
2208 hook_bool_const_tree_false)
2210 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
2211 one if they are compatible and two if they are nearly compatible
2212 (which causes a warning to be generated). */
2214 (comp_type_attributes,
2215 "If defined, this target hook is a function which returns zero if the attributes on\n\
2216 @var{type1} and @var{type2} are incompatible, one if they are compatible,\n\
2217 and two if they are nearly compatible (which causes a warning to be\n\
2218 generated). If this is not defined, machine-specific attributes are\n\
2219 supposed always to be compatible.",
2220 int, (const_tree type1, const_tree type2),
2221 hook_int_const_tree_const_tree_1)
2223 /* Assign default attributes to the newly defined TYPE. */
2225 (set_default_type_attributes,
2226 "If defined, this target hook is a function which assigns default attributes to\n\
2227 the newly defined @var{type}.",
2231 /* Insert attributes on the newly created DECL. */
2234 "Define this target hook if you want to be able to add attributes to a decl\n\
2235 when it is being created. This is normally useful for back ends which\n\
2236 wish to implement a pragma by using the attributes which correspond to\n\
2237 the pragma's effect. The @var{node} argument is the decl which is being\n\
2238 created. The @var{attr_ptr} argument is a pointer to the attribute list\n\
2239 for this decl. The list itself should not be modified, since it may be\n\
2240 shared with other decls, but attributes may be chained on the head of\n\
2241 the list and @code{*@var{attr_ptr}} modified to point to the new\n\
2242 attributes, or a copy of the list may be made if further changes are\n\
2244 void, (tree node, tree *attr_ptr),
2245 hook_void_tree_treeptr)
2247 /* Perform additional target-specific processing of generic attributes. */
2249 (handle_generic_attribute,
2250 "Define this target hook if you want to be able to perform additional\n\
2251 target-specific processing of an attribute which is handled generically\n\
2252 by a front end. The arguments are the same as those which are passed to\n\
2253 attribute handlers. So far this only affects the @var{noinit} and\n\
2254 @var{section} attribute.",
2255 tree, (tree *node, tree name, tree args, int flags, bool *no_add_attrs),
2256 hook_tree_treeptr_tree_tree_int_boolptr_null)
2258 /* Return true if FNDECL (which has at least one machine attribute)
2259 can be inlined despite its machine attributes, false otherwise. */
2261 (function_attribute_inlinable_p,
2262 "@cindex inlining\n\
2263 This target hook returns @code{true} if it is OK to inline @var{fndecl}\n\
2264 into the current function, despite its having target-specific\n\
2265 attributes, @code{false} otherwise. By default, if a function has a\n\
2266 target specific attribute attached to it, it will not be inlined.",
2267 bool, (const_tree fndecl),
2268 hook_bool_const_tree_false)
2270 /* Return true if bitfields in RECORD_TYPE should follow the
2271 Microsoft Visual C++ bitfield layout rules. */
2273 (ms_bitfield_layout_p,
2274 "This target hook returns @code{true} if bit-fields in the given\n\
2275 @var{record_type} are to be laid out following the rules of Microsoft\n\
2276 Visual C/C++, namely: (i) a bit-field won't share the same storage\n\
2277 unit with the previous bit-field if their underlying types have\n\
2278 different sizes, and the bit-field will be aligned to the highest\n\
2279 alignment of the underlying types of itself and of the previous\n\
2280 bit-field; (ii) a zero-sized bit-field will affect the alignment of\n\
2281 the whole enclosing structure, even if it is unnamed; except that\n\
2282 (iii) a zero-sized bit-field will be disregarded unless it follows\n\
2283 another bit-field of nonzero size. If this hook returns @code{true},\n\
2284 other macros that control bit-field layout are ignored.\n\
2286 When a bit-field is inserted into a packed record, the whole size\n\
2287 of the underlying type is used by one or more same-size adjacent\n\
2288 bit-fields (that is, if its long:3, 32 bits is used in the record,\n\
2289 and any additional adjacent long bit-fields are packed into the same\n\
2290 chunk of 32 bits. However, if the size changes, a new field of that\n\
2291 size is allocated). In an unpacked record, this is the same as using\n\
2292 alignment, but not equivalent when packing.\n\
2294 If both MS bit-fields and @samp{__attribute__((packed))} are used,\n\
2295 the latter will take precedence. If @samp{__attribute__((packed))} is\n\
2296 used on a single field when MS bit-fields are in use, it will take\n\
2297 precedence for that field, but the alignment of the rest of the structure\n\
2298 may affect its placement.",
2299 bool, (const_tree record_type),
2300 hook_bool_const_tree_false)
2302 /* For now this is only an interface to WORDS_BIG_ENDIAN for
2303 target-independent code like the front ends, need performance testing
2304 before switching completely to the target hook. */
2309 targhook_words_big_endian)
2311 /* Likewise for FLOAT_WORDS_BIG_ENDIAN. */
2313 (float_words_big_endian,
2316 targhook_float_words_big_endian)
2319 (float_exceptions_rounding_supported_p,
2320 "Returns true if the target supports IEEE 754 floating-point exceptions\
2321 and rounding modes, false otherwise. This is intended to relate to the\
2322 @code{float} and @code{double} types, but not necessarily @code{long double}.\
2323 By default, returns true if the @code{adddf3} instruction pattern is\
2324 available and false otherwise, on the assumption that hardware floating\
2325 point supports exceptions and rounding modes but software floating point\
2328 default_float_exceptions_rounding_supported_p)
2330 /* True if the target supports decimal floating point. */
2332 (decimal_float_supported_p,
2333 "Returns true if the target supports decimal floating point.",
2335 default_decimal_float_supported_p)
2337 /* True if the target supports fixed-point. */
2339 (fixed_point_supported_p,
2340 "Returns true if the target supports fixed-point arithmetic.",
2342 default_fixed_point_supported_p)
2344 /* Return true if anonymous bitfields affect structure alignment. */
2346 (align_anon_bitfield,
2347 "When @code{PCC_BITFIELD_TYPE_MATTERS} is true this hook will determine\n\
2348 whether unnamed bitfields affect the alignment of the containing\n\
2349 structure. The hook should return true if the structure should inherit\n\
2350 the alignment requirements of an unnamed bitfield's type.",
2352 hook_bool_void_false)
2354 /* Return true if volatile bitfields should use the narrowest type possible.
2355 Return false if they should use the container type. */
2357 (narrow_volatile_bitfield,
2358 "This target hook should return @code{true} if accesses to volatile bitfields\n\
2359 should use the narrowest mode possible. It should return @code{false} if\n\
2360 these accesses should use the bitfield container type.\n\
2362 The default is @code{false}.",
2364 hook_bool_void_false)
2366 /* Set up target-specific built-in functions. */
2369 "Define this hook if you have any machine-specific built-in functions\n\
2370 that need to be defined. It should be a function that performs the\n\
2373 Machine specific built-in functions can be useful to expand special machine\n\
2374 instructions that would otherwise not normally be generated because\n\
2375 they have no equivalent in the source language (for example, SIMD vector\n\
2376 instructions or prefetch instructions).\n\
2378 To create a built-in function, call the function\n\
2379 @code{lang_hooks.builtin_function}\n\
2380 which is defined by the language front end. You can use any type nodes set\n\
2381 up by @code{build_common_tree_nodes};\n\
2382 only language front ends that use those two functions will call\n\
2383 @samp{TARGET_INIT_BUILTINS}.",
2387 /* Initialize (if INITIALIZE_P is true) and return the target-specific
2388 built-in function decl for CODE.
2389 Return NULL if that is not possible. Return error_mark_node if CODE
2390 is outside of the range of valid target builtin function codes. */
2393 "Define this hook if you have any machine-specific built-in functions\n\
2394 that need to be defined. It should be a function that returns the\n\
2395 builtin function declaration for the builtin function code @var{code}.\n\
2396 If there is no such builtin and it cannot be initialized at this time\n\
2397 if @var{initialize_p} is true the function should return @code{NULL_TREE}.\n\
2398 If @var{code} is out of range the function should return\n\
2399 @code{error_mark_node}.",
2400 tree, (unsigned code, bool initialize_p), NULL)
2402 /* Expand a target-specific builtin. */
2406 Expand a call to a machine specific built-in function that was set up by\n\
2407 @samp{TARGET_INIT_BUILTINS}. @var{exp} is the expression for the\n\
2408 function call; the result should go to @var{target} if that is\n\
2409 convenient, and have mode @var{mode} if that is convenient.\n\
2410 @var{subtarget} may be used as the target for computing one of\n\
2411 @var{exp}'s operands. @var{ignore} is nonzero if the value is to be\n\
2412 ignored. This function should return the result of the call to the\n\
2413 built-in function.",
2415 (tree exp, rtx target, rtx subtarget, machine_mode mode, int ignore),
2416 default_expand_builtin)
2418 /* Select a replacement for a target-specific builtin. This is done
2419 *before* regular type checking, and so allows the target to
2420 implement a crude form of function overloading. The result is a
2421 complete expression that implements the operation. PARAMS really
2422 has type VEC(tree,gc)*, but we don't want to include tree.h here. */
2424 (resolve_overloaded_builtin,
2425 "Select a replacement for a machine specific built-in function that\n\
2426 was set up by @samp{TARGET_INIT_BUILTINS}. This is done\n\
2427 @emph{before} regular type checking, and so allows the target to\n\
2428 implement a crude form of function overloading. @var{fndecl} is the\n\
2429 declaration of the built-in function. @var{arglist} is the list of\n\
2430 arguments passed to the built-in function. The result is a\n\
2431 complete expression that implements the operation, usually\n\
2432 another @code{CALL_EXPR}.\n\
2433 @var{arglist} really has type @samp{VEC(tree,gc)*}",
2434 tree, (unsigned int /*location_t*/ loc, tree fndecl, void *arglist), NULL)
2437 (check_builtin_call,
2438 "Perform semantic checking on a call to a machine-specific built-in\n\
2439 function after its arguments have been constrained to the function\n\
2440 signature. Return true if the call is valid, otherwise report an error\n\
2441 and return false.\n\
2443 This hook is called after @code{TARGET_RESOLVE_OVERLOADED_BUILTIN}.\n\
2444 The call was originally to built-in function @var{orig_fndecl},\n\
2445 but after the optional @code{TARGET_RESOLVE_OVERLOADED_BUILTIN}\n\
2446 step is now to built-in function @var{fndecl}. @var{loc} is the\n\
2447 location of the call and @var{args} is an array of function arguments,\n\
2448 of which there are @var{nargs}. @var{arg_loc} specifies the location\n\
2450 bool, (location_t loc, vec<location_t> arg_loc, tree fndecl,
2451 tree orig_fndecl, unsigned int nargs, tree *args),
2454 /* Fold a target-specific builtin to a tree valid for both GIMPLE
2458 "Fold a call to a machine specific built-in function that was set up by\n\
2459 @samp{TARGET_INIT_BUILTINS}. @var{fndecl} is the declaration of the\n\
2460 built-in function. @var{n_args} is the number of arguments passed to\n\
2461 the function; the arguments themselves are pointed to by @var{argp}.\n\
2462 The result is another tree, valid for both GIMPLE and GENERIC,\n\
2463 containing a simplified expression for the call's result. If\n\
2464 @var{ignore} is true the value will be ignored.",
2465 tree, (tree fndecl, int n_args, tree *argp, bool ignore),
2466 hook_tree_tree_int_treep_bool_null)
2468 /* Fold a target-specific builtin to a valid GIMPLE tree. */
2470 (gimple_fold_builtin,
2471 "Fold a call to a machine specific built-in function that was set up\n\
2472 by @samp{TARGET_INIT_BUILTINS}. @var{gsi} points to the gimple\n\
2473 statement holding the function call. Returns true if any change\n\
2474 was made to the GIMPLE stream.",
2475 bool, (gimple_stmt_iterator *gsi),
2476 hook_bool_gsiptr_false)
2478 /* Target hook is used to compare the target attributes in two functions to
2479 determine which function's features get higher priority. This is used
2480 during function multi-versioning to figure out the order in which two
2481 versions must be dispatched. A function version with a higher priority
2482 is checked for dispatching earlier. DECL1 and DECL2 are
2483 the two function decls that will be compared. It returns positive value
2484 if DECL1 is higher priority, negative value if DECL2 is higher priority
2485 and 0 if they are the same. */
2487 (compare_version_priority,
2488 "This hook is used to compare the target attributes in two functions to\n\
2489 determine which function's features get higher priority. This is used\n\
2490 during function multi-versioning to figure out the order in which two\n\
2491 versions must be dispatched. A function version with a higher priority\n\
2492 is checked for dispatching earlier. @var{decl1} and @var{decl2} are\n\
2493 the two function decls that will be compared.",
2494 int, (tree decl1, tree decl2), NULL)
2496 /* Target hook is used to generate the dispatcher logic to invoke the right
2497 function version at run-time for a given set of function versions.
2498 ARG points to the callgraph node of the dispatcher function whose body
2499 must be generated. */
2501 (generate_version_dispatcher_body,
2502 "This hook is used to generate the dispatcher logic to invoke the right\n\
2503 function version at run-time for a given set of function versions.\n\
2504 @var{arg} points to the callgraph node of the dispatcher function whose\n\
2505 body must be generated.",
2506 tree, (void *arg), NULL)
2508 /* Target hook is used to get the dispatcher function for a set of function
2509 versions. The dispatcher function is called to invoke the right function
2510 version at run-time. DECL is one version from a set of semantically
2511 identical versions. */
2513 (get_function_versions_dispatcher,
2514 "This hook is used to get the dispatcher function for a set of function\n\
2515 versions. The dispatcher function is called to invoke the right function\n\
2516 version at run-time. @var{decl} is one version from a set of semantically\n\
2517 identical versions.",
2518 tree, (void *decl), NULL)
2520 /* Returns a code for a target-specific builtin that implements
2521 reciprocal of a target-specific function, or NULL_TREE if not available. */
2523 (builtin_reciprocal,
2524 "This hook should return the DECL of a function that implements the\n\
2525 reciprocal of the machine-specific builtin function @var{fndecl}, or\n\
2526 @code{NULL_TREE} if such a function is not available.",
2527 tree, (tree fndecl),
2528 default_builtin_reciprocal)
2530 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
2531 string containing the C++ mangling for TYPE. In all other cases, return
2535 "If your target defines any fundamental types, or any types your target\n\
2536 uses should be mangled differently from the default, define this hook\n\
2537 to return the appropriate encoding for these types as part of a C++\n\
2538 mangled name. The @var{type} argument is the tree structure representing\n\
2539 the type to be mangled. The hook may be applied to trees which are\n\
2540 not target-specific fundamental types; it should return @code{NULL}\n\
2541 for all such types, as well as arguments it does not recognize. If the\n\
2542 return value is not @code{NULL}, it must point to a statically-allocated\n\
2545 Target-specific fundamental types might be new fundamental types or\n\
2546 qualified versions of ordinary fundamental types. Encode new\n\
2547 fundamental types as @samp{@w{u @var{n} @var{name}}}, where @var{name}\n\
2548 is the name used for the type in source code, and @var{n} is the\n\
2549 length of @var{name} in decimal. Encode qualified versions of\n\
2550 ordinary types as @samp{@w{U @var{n} @var{name} @var{code}}}, where\n\
2551 @var{name} is the name used for the type qualifier in source code,\n\
2552 @var{n} is the length of @var{name} as above, and @var{code} is the\n\
2553 code used to represent the unqualified version of this type. (See\n\
2554 @code{write_builtin_type} in @file{cp/mangle.c} for the list of\n\
2555 codes.) In both cases the spaces are for clarity; do not include any\n\
2556 spaces in your string.\n\
2558 This hook is applied to types prior to typedef resolution. If the mangled\n\
2559 name for a particular type depends only on that type's main variant, you\n\
2560 can perform typedef resolution yourself using @code{TYPE_MAIN_VARIANT}\n\
2563 The default version of this hook always returns @code{NULL}, which is\n\
2564 appropriate for a target that does not define any new fundamental\n\
2566 const char *, (const_tree type),
2567 hook_constcharptr_const_tree_null)
2569 /* Make any adjustments to libfunc names needed for this target. */
2572 "This hook should declare additional library routines or rename\n\
2573 existing ones, using the functions @code{set_optab_libfunc} and\n\
2574 @code{init_one_libfunc} defined in @file{optabs.c}.\n\
2575 @code{init_optabs} calls this macro after initializing all the normal\n\
2576 library routines.\n\
2578 The default is to do nothing. Most ports don't need to define this hook.",
2582 /* Add a __gnu_ prefix to library functions rather than just __. */
2584 (libfunc_gnu_prefix,
2585 "If false (the default), internal library routines start with two\n\
2586 underscores. If set to true, these routines start with @code{__gnu_}\n\
2587 instead. E.g., @code{__muldi3} changes to @code{__gnu_muldi3}. This\n\
2588 currently only affects functions defined in @file{libgcc2.c}. If this\n\
2589 is set to true, the @file{tm.h} file must also\n\
2590 @code{#define LIBGCC2_GNU_PREFIX}.",
2593 /* Given a decl, a section name, and whether the decl initializer
2594 has relocs, choose attributes for the section. */
2595 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
2597 (section_type_flags,
2598 "Choose a set of section attributes for use by @code{TARGET_ASM_NAMED_SECTION}\n\
2599 based on a variable or function decl, a section name, and whether or not the\n\
2600 declaration's initializer may contain runtime relocations. @var{decl} may be\n\
2601 null, in which case read-write data should be assumed.\n\
2603 The default version of this function handles choosing code vs data,\n\
2604 read-only vs read-write data, and @code{flag_pic}. You should only\n\
2605 need to override this if your target has special flags that might be\n\
2606 set via @code{__attribute__}.",
2607 unsigned int, (tree decl, const char *name, int reloc),
2608 default_section_type_flags)
2612 "This hook determines whether a function from a class of functions\n\
2613 @var{fn_class} is present in the target C library. If @var{type} is NULL,\n\
2614 the caller asks for support for all standard (float, double, long double)\n\
2615 types. If @var{type} is non-NULL, the caller asks for support for a\n\
2617 bool, (enum function_class fn_class, tree type),
2618 default_libc_has_function)
2621 (libc_has_fast_function,
2622 "This hook determines whether a function from a class of functions\n\
2623 @code{(enum function_class)}@var{fcode} has a fast implementation.",
2625 default_libc_has_fast_function)
2627 /* True if new jumps cannot be created, to replace existing ones or
2628 not, at the current point in the compilation. */
2630 (cannot_modify_jumps_p,
2631 "This target hook returns @code{true} past the point in which new jump\n\
2632 instructions could be created. On machines that require a register for\n\
2633 every jump such as the SHmedia ISA of SH5, this point would typically be\n\
2634 reload, so this target hook should be defined to a function such as:\n\
2638 cannot_modify_jumps_past_reload_p ()\n\
2640 return (reload_completed || reload_in_progress);\n\
2644 hook_bool_void_false)
2646 /* True if FOLLOWER may be modified to follow FOLLOWEE. */
2649 "FOLLOWER and FOLLOWEE are JUMP_INSN instructions;\
2650 return true if FOLLOWER may be modified to follow FOLLOWEE;\
2651 false, if it can't.\
2652 For example, on some targets, certain kinds of branches can't be made to\
2653 follow through a hot/cold partitioning.",
2654 bool, (const rtx_insn *follower, const rtx_insn *followee),
2655 hook_bool_const_rtx_insn_const_rtx_insn_true)
2657 /* Return true if the target supports conditional execution. */
2659 (have_conditional_execution,
2660 "This target hook returns true if the target supports conditional execution.\n\
2661 This target hook is required only when the target has several different\n\
2662 modes and they have different conditional execution capability, such as ARM.",
2664 default_have_conditional_execution)
2668 "This function prepares to emit a comparison insn for the first compare in a\n\
2669 sequence of conditional comparisions. It returns an appropriate comparison\n\
2670 with @code{CC} for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2671 The insns to prepare the compare are saved in @var{prep_seq} and the compare\n\
2672 insns are saved in @var{gen_seq}. They will be emitted when all the\n\
2673 compares in the conditional comparision are generated without error.\n\
2674 @var{code} is the @code{rtx_code} of the compare for @var{op0} and @var{op1}.",
2675 rtx, (rtx_insn **prep_seq, rtx_insn **gen_seq, int code, tree op0, tree op1),
2680 "This function prepares to emit a conditional comparison within a sequence\n\
2681 of conditional comparisons. It returns an appropriate comparison with\n\
2682 @code{CC} for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2683 The insns to prepare the compare are saved in @var{prep_seq} and the compare\n\
2684 insns are saved in @var{gen_seq}. They will be emitted when all the\n\
2685 compares in the conditional comparision are generated without error. The\n\
2686 @var{prev} expression is the result of a prior call to @code{gen_ccmp_first}\n\
2687 or @code{gen_ccmp_next}. It may return @code{NULL} if the combination of\n\
2688 @var{prev} and this comparison is not supported, otherwise the result must\n\
2689 be appropriate for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2690 @var{code} is the @code{rtx_code} of the compare for @var{op0} and @var{op1}.\n\
2691 @var{bit_code} is @code{AND} or @code{IOR}, which is the op on the compares.",
2692 rtx, (rtx_insn **prep_seq, rtx_insn **gen_seq, rtx prev, int cmp_code, tree op0, tree op1, int bit_code),
2695 /* Return a new value for loop unroll size. */
2697 (loop_unroll_adjust,
2698 "This target hook returns a new value for the number of times @var{loop}\n\
2699 should be unrolled. The parameter @var{nunroll} is the number of times\n\
2700 the loop is to be unrolled. The parameter @var{loop} is a pointer to\n\
2701 the loop, which is going to be checked for unrolling. This target hook\n\
2702 is required only when the target has special constraints like maximum\n\
2703 number of memory accesses.",
2704 unsigned, (unsigned nunroll, class loop *loop),
2707 /* True if X is a legitimate MODE-mode immediate operand. */
2709 (legitimate_constant_p,
2710 "This hook returns true if @var{x} is a legitimate constant for a\n\
2711 @var{mode}-mode immediate operand on the target machine. You can assume that\n\
2712 @var{x} satisfies @code{CONSTANT_P}, so you need not check this.\n\
2714 The default definition returns true.",
2715 bool, (machine_mode mode, rtx x),
2716 hook_bool_mode_rtx_true)
2718 /* True if X is a TLS operand whose value should be pre-computed. */
2721 "This hook returns true if @var{x} is a TLS operand on the target\n\
2722 machine that should be pre-computed when used as the argument in a call.\n\
2723 You can assume that @var{x} satisfies @code{CONSTANT_P}, so you need not \n\
2726 The default definition returns false.",
2727 bool, (machine_mode mode, rtx x),
2728 hook_bool_mode_rtx_false)
2730 /* True if the constant X cannot be placed in the constant pool. */
2732 (cannot_force_const_mem,
2733 "This hook should return true if @var{x} is of a form that cannot (or\n\
2734 should not) be spilled to the constant pool. @var{mode} is the mode\n\
2737 The default version of this hook returns false.\n\
2739 The primary reason to define this hook is to prevent reload from\n\
2740 deciding that a non-legitimate constant would be better reloaded\n\
2741 from the constant pool instead of spilling and reloading a register\n\
2742 holding the constant. This restriction is often true of addresses\n\
2743 of TLS symbols for various targets.",
2744 bool, (machine_mode mode, rtx x),
2745 hook_bool_mode_rtx_false)
2748 (cannot_copy_insn_p,
2749 "True if the insn @var{x} cannot be duplicated.",
2750 bool, (rtx_insn *), NULL)
2752 /* True if X is considered to be commutative. */
2755 "This target hook returns @code{true} if @var{x} is considered to be commutative.\n\
2756 Usually, this is just COMMUTATIVE_P (@var{x}), but the HP PA doesn't consider\n\
2757 PLUS to be commutative inside a MEM@. @var{outer_code} is the rtx code\n\
2758 of the enclosing rtl, if known, otherwise it is UNKNOWN.",
2759 bool, (const_rtx x, int outer_code),
2760 hook_bool_const_rtx_commutative_p)
2762 /* True if ADDR is an address-expression whose effect depends
2763 on the mode of the memory reference it is used in. */
2765 (mode_dependent_address_p,
2766 "This hook returns @code{true} if memory address @var{addr} in address\n\
2767 space @var{addrspace} can have\n\
2768 different meanings depending on the machine mode of the memory\n\
2769 reference it is used for or if the address is valid for some modes\n\
2772 Autoincrement and autodecrement addresses typically have mode-dependent\n\
2773 effects because the amount of the increment or decrement is the size\n\
2774 of the operand being addressed. Some machines have other mode-dependent\n\
2775 addresses. Many RISC machines have no mode-dependent addresses.\n\
2777 You may assume that @var{addr} is a valid address for the machine.\n\
2779 The default version of this hook returns @code{false}.",
2780 bool, (const_rtx addr, addr_space_t addrspace),
2781 default_mode_dependent_address_p)
2783 /* Given an invalid address X for a given machine mode, try machine-specific
2784 ways to make it legitimate. Return X or an invalid address on failure. */
2786 (legitimize_address,
2787 "This hook is given an invalid memory address @var{x} for an\n\
2788 operand of mode @var{mode} and should try to return a valid memory\n\
2791 @findex break_out_memory_refs\n\
2792 @var{x} will always be the result of a call to @code{break_out_memory_refs},\n\
2793 and @var{oldx} will be the operand that was given to that function to produce\n\
2796 The code of the hook should not alter the substructure of\n\
2797 @var{x}. If it transforms @var{x} into a more legitimate form, it\n\
2798 should return the new @var{x}.\n\
2800 It is not necessary for this hook to come up with a legitimate address,\n\
2801 with the exception of native TLS addresses (@pxref{Emulated TLS}).\n\
2802 The compiler has standard ways of doing so in all cases. In fact, if\n\
2803 the target supports only emulated TLS, it\n\
2804 is safe to omit this hook or make it return @var{x} if it cannot find\n\
2805 a valid way to legitimize the address. But often a machine-dependent\n\
2806 strategy can generate better code.",
2807 rtx, (rtx x, rtx oldx, machine_mode mode),
2808 default_legitimize_address)
2810 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
2812 (delegitimize_address,
2813 "This hook is used to undo the possibly obfuscating effects of the\n\
2814 @code{LEGITIMIZE_ADDRESS} and @code{LEGITIMIZE_RELOAD_ADDRESS} target\n\
2815 macros. Some backend implementations of these macros wrap symbol\n\
2816 references inside an @code{UNSPEC} rtx to represent PIC or similar\n\
2817 addressing modes. This target hook allows GCC's optimizers to understand\n\
2818 the semantics of these opaque @code{UNSPEC}s by converting them back\n\
2819 into their original form.",
2821 delegitimize_mem_from_attrs)
2823 /* Given an RTX, return true if it is not ok to emit it into debug info
2826 (const_not_ok_for_debug_p,
2827 "This hook should return true if @var{x} should not be emitted into\n\
2830 default_const_not_ok_for_debug_p)
2832 /* Given an address RTX, say whether it is valid. */
2834 (legitimate_address_p,
2835 "A function that returns whether @var{x} (an RTX) is a legitimate memory\n\
2836 address on the target machine for a memory operand of mode @var{mode}.\n\
2838 Legitimate addresses are defined in two variants: a strict variant and a\n\
2839 non-strict one. The @var{strict} parameter chooses which variant is\n\
2840 desired by the caller.\n\
2842 The strict variant is used in the reload pass. It must be defined so\n\
2843 that any pseudo-register that has not been allocated a hard register is\n\
2844 considered a memory reference. This is because in contexts where some\n\
2845 kind of register is required, a pseudo-register with no hard register\n\
2846 must be rejected. For non-hard registers, the strict variant should look\n\
2847 up the @code{reg_renumber} array; it should then proceed using the hard\n\
2848 register number in the array, or treat the pseudo as a memory reference\n\
2849 if the array holds @code{-1}.\n\
2851 The non-strict variant is used in other passes. It must be defined to\n\
2852 accept all pseudo-registers in every context where some kind of\n\
2853 register is required.\n\
2855 Normally, constant addresses which are the sum of a @code{symbol_ref}\n\
2856 and an integer are stored inside a @code{const} RTX to mark them as\n\
2857 constant. Therefore, there is no need to recognize such sums\n\
2858 specifically as legitimate addresses. Normally you would simply\n\
2859 recognize any @code{const} as legitimate.\n\
2861 Usually @code{PRINT_OPERAND_ADDRESS} is not prepared to handle constant\n\
2862 sums that are not marked with @code{const}. It assumes that a naked\n\
2863 @code{plus} indicates indexing. If so, then you @emph{must} reject such\n\
2864 naked constant sums as illegitimate addresses, so that none of them will\n\
2865 be given to @code{PRINT_OPERAND_ADDRESS}.\n\
2867 @cindex @code{TARGET_ENCODE_SECTION_INFO} and address validation\n\
2868 On some machines, whether a symbolic address is legitimate depends on\n\
2869 the section that the address refers to. On these machines, define the\n\
2870 target hook @code{TARGET_ENCODE_SECTION_INFO} to store the information\n\
2871 into the @code{symbol_ref}, and then check for it here. When you see a\n\
2872 @code{const}, you will have to look inside it to find the\n\
2873 @code{symbol_ref} in order to determine the section. @xref{Assembler\n\
2876 @cindex @code{GO_IF_LEGITIMATE_ADDRESS}\n\
2877 Some ports are still using a deprecated legacy substitute for\n\
2878 this hook, the @code{GO_IF_LEGITIMATE_ADDRESS} macro. This macro\n\
2882 #define GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label})\n\
2886 and should @code{goto @var{label}} if the address @var{x} is a valid\n\
2887 address on the target machine for a memory operand of mode @var{mode}.\n\
2889 @findex REG_OK_STRICT\n\
2890 Compiler source files that want to use the strict variant of this\n\
2891 macro define the macro @code{REG_OK_STRICT}. You should use an\n\
2892 @code{#ifdef REG_OK_STRICT} conditional to define the strict variant in\n\
2893 that case and the non-strict variant otherwise.\n\
2895 Using the hook is usually simpler because it limits the number of\n\
2896 files that are recompiled when changes are made.",
2897 bool, (machine_mode mode, rtx x, bool strict),
2898 default_legitimate_address_p)
2900 /* True if the given constant can be put into an object_block. */
2902 (use_blocks_for_constant_p,
2903 "This hook should return true if pool entries for constant @var{x} can\n\
2904 be placed in an @code{object_block} structure. @var{mode} is the mode\n\
2907 The default version returns false for all constants.",
2908 bool, (machine_mode mode, const_rtx x),
2909 hook_bool_mode_const_rtx_false)
2911 /* True if the given decl can be put into an object_block. */
2913 (use_blocks_for_decl_p,
2914 "This hook should return true if pool entries for @var{decl} should\n\
2915 be placed in an @code{object_block} structure.\n\
2917 The default version returns true for all decls.",
2918 bool, (const_tree decl),
2919 hook_bool_const_tree_true)
2921 /* The minimum and maximum byte offsets for anchored addresses. */
2924 "The minimum offset that should be applied to a section anchor.\n\
2925 On most targets, it should be the smallest offset that can be\n\
2926 applied to a base register while still giving a legitimate address\n\
2927 for every mode. The default value is 0.",
2932 "Like @code{TARGET_MIN_ANCHOR_OFFSET}, but the maximum (inclusive)\n\
2933 offset that should be applied to section anchors. The default\n\
2937 /* True if section anchors can be used to access the given symbol. */
2939 (use_anchors_for_symbol_p,
2940 "Return true if GCC should attempt to use anchors to access @code{SYMBOL_REF}\n\
2941 @var{x}. You can assume @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})} and\n\
2942 @samp{!SYMBOL_REF_ANCHOR_P (@var{x})}.\n\
2944 The default version is correct for most targets, but you might need to\n\
2945 intercept this hook to handle things like target-specific attributes\n\
2946 or target-specific sections.",
2947 bool, (const_rtx x),
2948 default_use_anchors_for_symbol_p)
2950 /* True if target supports indirect functions. */
2953 "It returns true if the target supports GNU indirect functions.\n\
2954 The support includes the assembler, linker and dynamic linker.\n\
2955 The default value of this hook is based on target's libc.",
2957 default_has_ifunc_p)
2959 /* True if it is OK to do sibling call optimization for the specified
2960 call expression EXP. DECL will be the called function, or NULL if
2961 this is an indirect call. */
2963 (function_ok_for_sibcall,
2964 "True if it is OK to do sibling call optimization for the specified\n\
2965 call expression @var{exp}. @var{decl} will be the called function,\n\
2966 or @code{NULL} if this is an indirect call.\n\
2968 It is not uncommon for limitations of calling conventions to prevent\n\
2969 tail calls to functions outside the current unit of translation, or\n\
2970 during PIC compilation. The hook is used to enforce these restrictions,\n\
2971 as the @code{sibcall} md pattern cannot fail, or fall over to a\n\
2972 ``normal'' call. The criteria for successful sibling call optimization\n\
2973 may vary greatly between different architectures.",
2974 bool, (tree decl, tree exp),
2975 hook_bool_tree_tree_false)
2977 /* Establish appropriate back-end context for processing the function
2978 FNDECL. The argument might be NULL to indicate processing at top
2979 level, outside of any function scope. */
2981 (set_current_function,
2982 "The compiler invokes this hook whenever it changes its current function\n\
2983 context (@code{cfun}). You can define this function if\n\
2984 the back end needs to perform any initialization or reset actions on a\n\
2985 per-function basis. For example, it may be used to implement function\n\
2986 attributes that affect register usage or code generation patterns.\n\
2987 The argument @var{decl} is the declaration for the new function context,\n\
2988 and may be null to indicate that the compiler has left a function context\n\
2989 and is returning to processing at the top level.\n\
2990 The default hook function does nothing.\n\
2992 GCC sets @code{cfun} to a dummy function context during initialization of\n\
2993 some parts of the back end. The hook function is not invoked in this\n\
2994 situation; you need not worry about the hook being invoked recursively,\n\
2995 or when the back end is in a partially-initialized state.\n\
2996 @code{cfun} might be @code{NULL} to indicate processing at top level,\n\
2997 outside of any function scope.",
2998 void, (tree decl), hook_void_tree)
3000 /* True if EXP should be placed in a "small data" section. */
3003 "Returns true if @var{exp} should be placed into a ``small data'' section.\n\
3004 The default version of this hook always returns false.",
3005 bool, (const_tree exp),
3006 hook_bool_const_tree_false)
3008 /* True if EXP names an object for which name resolution must resolve
3009 to the current executable or shared library. */
3012 "Returns true if @var{exp} names an object for which name resolution\n\
3013 rules must resolve to the current ``module'' (dynamic shared library\n\
3014 or executable image).\n\
3016 The default version of this hook implements the name resolution rules\n\
3017 for ELF, which has a looser model of global name binding than other\n\
3018 currently supported object file formats.",
3019 bool, (const_tree exp),
3020 default_binds_local_p)
3022 /* Check if profiling code is before or after prologue. */
3024 (profile_before_prologue,
3025 "It returns true if target wants profile code emitted before prologue.\n\n\
3026 The default version of this hook use the target macro\n\
3027 @code{PROFILE_BEFORE_PROLOGUE}.",
3029 default_profile_before_prologue)
3031 /* Return true if a leaf function should stay leaf even with profiling
3034 (keep_leaf_when_profiled,
3035 "This target hook returns true if the target wants the leaf flag for\
3036 the current function to stay true even if it calls mcount. This might\
3037 make sense for targets using the leaf flag only to determine whether a\
3038 stack frame needs to be generated or not and for which the call to\
3039 mcount is generated before the function prologue.",
3041 default_keep_leaf_when_profiled)
3043 /* Modify and return the identifier of a DECL's external name,
3044 originally identified by ID, as required by the target,
3045 (eg, append @nn to windows32 stdcall function names).
3046 The default is to return ID without modification. */
3048 (mangle_decl_assembler_name,
3049 "Define this hook if you need to postprocess the assembler name generated\n\
3050 by target-independent code. The @var{id} provided to this hook will be\n\
3051 the computed name (e.g., the macro @code{DECL_NAME} of the @var{decl} in C,\n\
3052 or the mangled name of the @var{decl} in C++). The return value of the\n\
3053 hook is an @code{IDENTIFIER_NODE} for the appropriate mangled name on\n\
3054 your target system. The default implementation of this hook just\n\
3055 returns the @var{id} provided.",
3056 tree, (tree decl, tree id),
3057 default_mangle_decl_assembler_name)
3059 /* Do something target-specific to record properties of the DECL into
3060 the associated SYMBOL_REF. */
3062 (encode_section_info,
3063 "Define this hook if references to a symbol or a constant must be\n\
3064 treated differently depending on something about the variable or\n\
3065 function named by the symbol (such as what section it is in).\n\
3067 The hook is executed immediately after rtl has been created for\n\
3068 @var{decl}, which may be a variable or function declaration or\n\
3069 an entry in the constant pool. In either case, @var{rtl} is the\n\
3070 rtl in question. Do @emph{not} use @code{DECL_RTL (@var{decl})}\n\
3071 in this hook; that field may not have been initialized yet.\n\
3073 In the case of a constant, it is safe to assume that the rtl is\n\
3074 a @code{mem} whose address is a @code{symbol_ref}. Most decls\n\
3075 will also have this form, but that is not guaranteed. Global\n\
3076 register variables, for instance, will have a @code{reg} for their\n\
3077 rtl. (Normally the right thing to do with such unusual rtl is\n\
3080 The @var{new_decl_p} argument will be true if this is the first time\n\
3081 that @code{TARGET_ENCODE_SECTION_INFO} has been invoked on this decl. It will\n\
3082 be false for subsequent invocations, which will happen for duplicate\n\
3083 declarations. Whether or not anything must be done for the duplicate\n\
3084 declaration depends on whether the hook examines @code{DECL_ATTRIBUTES}.\n\
3085 @var{new_decl_p} is always true when the hook is called for a constant.\n\
3087 @cindex @code{SYMBOL_REF_FLAG}, in @code{TARGET_ENCODE_SECTION_INFO}\n\
3088 The usual thing for this hook to do is to record flags in the\n\
3089 @code{symbol_ref}, using @code{SYMBOL_REF_FLAG} or @code{SYMBOL_REF_FLAGS}.\n\
3090 Historically, the name string was modified if it was necessary to\n\
3091 encode more than one bit of information, but this practice is now\n\
3092 discouraged; use @code{SYMBOL_REF_FLAGS}.\n\
3094 The default definition of this hook, @code{default_encode_section_info}\n\
3095 in @file{varasm.c}, sets a number of commonly-useful bits in\n\
3096 @code{SYMBOL_REF_FLAGS}. Check whether the default does what you need\n\
3097 before overriding it.",
3098 void, (tree decl, rtx rtl, int new_decl_p),
3099 default_encode_section_info)
3101 /* Undo the effects of encode_section_info on the symbol string. */
3103 (strip_name_encoding,
3104 "Decode @var{name} and return the real name part, sans\n\
3105 the characters that @code{TARGET_ENCODE_SECTION_INFO}\n\
3107 const char *, (const char *name),
3108 default_strip_name_encoding)
3110 /* If shift optabs for MODE are known to always truncate the shift count,
3111 return the mask that they apply. Return 0 otherwise. */
3113 (shift_truncation_mask,
3114 "This function describes how the standard shift patterns for @var{mode}\n\
3115 deal with shifts by negative amounts or by more than the width of the mode.\n\
3116 @xref{shift patterns}.\n\
3118 On many machines, the shift patterns will apply a mask @var{m} to the\n\
3119 shift count, meaning that a fixed-width shift of @var{x} by @var{y} is\n\
3120 equivalent to an arbitrary-width shift of @var{x} by @var{y & m}. If\n\
3121 this is true for mode @var{mode}, the function should return @var{m},\n\
3122 otherwise it should return 0. A return value of 0 indicates that no\n\
3123 particular behavior is guaranteed.\n\
3125 Note that, unlike @code{SHIFT_COUNT_TRUNCATED}, this function does\n\
3126 @emph{not} apply to general shift rtxes; it applies only to instructions\n\
3127 that are generated by the named shift patterns.\n\
3129 The default implementation of this function returns\n\
3130 @code{GET_MODE_BITSIZE (@var{mode}) - 1} if @code{SHIFT_COUNT_TRUNCATED}\n\
3131 and 0 otherwise. This definition is always safe, but if\n\
3132 @code{SHIFT_COUNT_TRUNCATED} is false, and some shift patterns\n\
3133 nevertheless truncate the shift count, you may get better code\n\
3135 unsigned HOST_WIDE_INT, (machine_mode mode),
3136 default_shift_truncation_mask)
3138 /* Return the number of divisions in the given MODE that should be present,
3139 so that it is profitable to turn the division into a multiplication by
3142 (min_divisions_for_recip_mul,
3143 "When @option{-ffast-math} is in effect, GCC tries to optimize\n\
3144 divisions by the same divisor, by turning them into multiplications by\n\
3145 the reciprocal. This target hook specifies the minimum number of divisions\n\
3146 that should be there for GCC to perform the optimization for a variable\n\
3147 of mode @var{mode}. The default implementation returns 3 if the machine\n\
3148 has an instruction for the division, and 2 if it does not.",
3149 unsigned int, (machine_mode mode),
3150 default_min_divisions_for_recip_mul)
3153 (truly_noop_truncation,
3154 "This hook returns true if it is safe to ``convert'' a value of\n\
3155 @var{inprec} bits to one of @var{outprec} bits (where @var{outprec} is\n\
3156 smaller than @var{inprec}) by merely operating on it as if it had only\n\
3157 @var{outprec} bits. The default returns true unconditionally, which\n\
3158 is correct for most machines. When @code{TARGET_TRULY_NOOP_TRUNCATION}\n\
3159 returns false, the machine description should provide a @code{trunc}\n\
3160 optab to specify the RTL that performs the required truncation.\n\
3162 If @code{TARGET_MODES_TIEABLE_P} returns false for a pair of modes,\n\
3163 suboptimal code can result if this hook returns true for the corresponding\n\
3164 mode sizes. Making this hook return false in such cases may improve things.",
3165 bool, (poly_uint64 outprec, poly_uint64 inprec),
3166 hook_bool_puint64_puint64_true)
3168 /* If the representation of integral MODE is such that values are
3169 always sign-extended to a wider mode MODE_REP then return
3170 SIGN_EXTEND. Return UNKNOWN otherwise. */
3171 /* Note that the return type ought to be RTX_CODE, but that's not
3172 necessarily defined at this point. */
3175 "The representation of an integral mode can be such that the values\n\
3176 are always extended to a wider integral mode. Return\n\
3177 @code{SIGN_EXTEND} if values of @var{mode} are represented in\n\
3178 sign-extended form to @var{rep_mode}. Return @code{UNKNOWN}\n\
3179 otherwise. (Currently, none of the targets use zero-extended\n\
3180 representation this way so unlike @code{LOAD_EXTEND_OP},\n\
3181 @code{TARGET_MODE_REP_EXTENDED} is expected to return either\n\
3182 @code{SIGN_EXTEND} or @code{UNKNOWN}. Also no target extends\n\
3183 @var{mode} to @var{rep_mode} so that @var{rep_mode} is not the next\n\
3184 widest integral mode and currently we take advantage of this fact.)\n\
3186 Similarly to @code{LOAD_EXTEND_OP} you may return a non-@code{UNKNOWN}\n\
3187 value even if the extension is not performed on certain hard registers\n\
3188 as long as for the @code{REGNO_REG_CLASS} of these hard registers\n\
3189 @code{TARGET_CAN_CHANGE_MODE_CLASS} returns false.\n\
3191 Note that @code{TARGET_MODE_REP_EXTENDED} and @code{LOAD_EXTEND_OP}\n\
3192 describe two related properties. If you define\n\
3193 @code{TARGET_MODE_REP_EXTENDED (mode, word_mode)} you probably also want\n\
3194 to define @code{LOAD_EXTEND_OP (mode)} to return the same type of\n\
3197 In order to enforce the representation of @code{mode},\n\
3198 @code{TARGET_TRULY_NOOP_TRUNCATION} should return false when truncating to\n\
3200 int, (scalar_int_mode mode, scalar_int_mode rep_mode),
3201 default_mode_rep_extended)
3204 (setjmp_preserves_nonvolatile_regs_p,
3205 "On some targets, it is assumed that the compiler will spill all pseudos\n\
3206 that are live across a call to @code{setjmp}, while other targets treat\n\
3207 @code{setjmp} calls as normal function calls.\n\
3209 This hook returns false if @code{setjmp} calls do not preserve all\n\
3210 non-volatile registers so that gcc that must spill all pseudos that are\n\
3211 live across @code{setjmp} calls. Define this to return true if the\n\
3212 target does not need to spill all pseudos live across @code{setjmp} calls.\n\
3213 The default implementation conservatively assumes all pseudos must be\n\
3214 spilled across @code{setjmp} calls.",
3216 hook_bool_void_false)
3218 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
3220 (valid_pointer_mode,
3221 "Define this to return nonzero if the port can handle pointers\n\
3222 with machine mode @var{mode}. The default version of this\n\
3223 hook returns true for both @code{ptr_mode} and @code{Pmode}.",
3224 bool, (scalar_int_mode mode),
3225 default_valid_pointer_mode)
3227 /* Disambiguate with errno. */
3229 (ref_may_alias_errno,
3230 "Define this to return nonzero if the memory reference @var{ref}\
3231 may alias with the system C library errno location. The default\
3232 version of this hook assumes the system C library errno location\
3233 is either a declaration of type int or accessed by dereferencing\
3235 bool, (ao_ref *ref),
3236 default_ref_may_alias_errno)
3238 /* Support for named address spaces. */
3240 #define HOOK_PREFIX "TARGET_ADDR_SPACE_"
3241 HOOK_VECTOR (TARGET_ADDR_SPACE_HOOKS, addr_space)
3243 /* MODE to use for a pointer into another address space. */
3246 "Define this to return the machine mode to use for pointers to\n\
3247 @var{address_space} if the target supports named address spaces.\n\
3248 The default version of this hook returns @code{ptr_mode}.",
3249 scalar_int_mode, (addr_space_t address_space),
3250 default_addr_space_pointer_mode)
3252 /* MODE to use for an address in another address space. */
3255 "Define this to return the machine mode to use for addresses in\n\
3256 @var{address_space} if the target supports named address spaces.\n\
3257 The default version of this hook returns @code{Pmode}.",
3258 scalar_int_mode, (addr_space_t address_space),
3259 default_addr_space_address_mode)
3261 /* True if MODE is valid for a pointer in __attribute__((mode("MODE")))
3262 in another address space. */
3264 (valid_pointer_mode,
3265 "Define this to return nonzero if the port can handle pointers\n\
3266 with machine mode @var{mode} to address space @var{as}. This target\n\
3267 hook is the same as the @code{TARGET_VALID_POINTER_MODE} target hook,\n\
3268 except that it includes explicit named address space support. The default\n\
3269 version of this hook returns true for the modes returned by either the\n\
3270 @code{TARGET_ADDR_SPACE_POINTER_MODE} or @code{TARGET_ADDR_SPACE_ADDRESS_MODE}\n\
3271 target hooks for the given address space.",
3272 bool, (scalar_int_mode mode, addr_space_t as),
3273 default_addr_space_valid_pointer_mode)
3275 /* True if an address is a valid memory address to a given named address
3276 space for a given mode. */
3278 (legitimate_address_p,
3279 "Define this to return true if @var{exp} is a valid address for mode\n\
3280 @var{mode} in the named address space @var{as}. The @var{strict}\n\
3281 parameter says whether strict addressing is in effect after reload has\n\
3282 finished. This target hook is the same as the\n\
3283 @code{TARGET_LEGITIMATE_ADDRESS_P} target hook, except that it includes\n\
3284 explicit named address space support.",
3285 bool, (machine_mode mode, rtx exp, bool strict, addr_space_t as),
3286 default_addr_space_legitimate_address_p)
3288 /* Return an updated address to convert an invalid pointer to a named
3289 address space to a valid one. If NULL_RTX is returned use machine
3290 independent methods to make the address valid. */
3292 (legitimize_address,
3293 "Define this to modify an invalid address @var{x} to be a valid address\n\
3294 with mode @var{mode} in the named address space @var{as}. This target\n\
3295 hook is the same as the @code{TARGET_LEGITIMIZE_ADDRESS} target hook,\n\
3296 except that it includes explicit named address space support.",
3297 rtx, (rtx x, rtx oldx, machine_mode mode, addr_space_t as),
3298 default_addr_space_legitimize_address)
3300 /* True if one named address space is a subset of another named address. */
3303 "Define this to return whether the @var{subset} named address space is\n\
3304 contained within the @var{superset} named address space. Pointers to\n\
3305 a named address space that is a subset of another named address space\n\
3306 will be converted automatically without a cast if used together in\n\
3307 arithmetic operations. Pointers to a superset address space can be\n\
3308 converted to pointers to a subset address space via explicit casts.",
3309 bool, (addr_space_t subset, addr_space_t superset),
3310 default_addr_space_subset_p)
3312 /* True if 0 is a valid address in the address space, or false if
3313 0 is a NULL in the address space. */
3315 (zero_address_valid,
3316 "Define this to modify the default handling of address 0 for the\n\
3317 address space. Return true if 0 should be considered a valid address.",
3318 bool, (addr_space_t as),
3319 default_addr_space_zero_address_valid)
3321 /* Function to convert an rtl expression from one address space to another. */
3324 "Define this to convert the pointer expression represented by the RTL\n\
3325 @var{op} with type @var{from_type} that points to a named address\n\
3326 space to a new pointer expression with type @var{to_type} that points\n\
3327 to a different named address space. When this hook it called, it is\n\
3328 guaranteed that one of the two address spaces is a subset of the other,\n\
3329 as determined by the @code{TARGET_ADDR_SPACE_SUBSET_P} target hook.",
3330 rtx, (rtx op, tree from_type, tree to_type),
3331 default_addr_space_convert)
3333 /* Function to encode an address space into dwarf. */
3336 "Define this to define how the address space is encoded in dwarf.\n\
3337 The result is the value to be used with @code{DW_AT_address_class}.",
3338 int, (addr_space_t as),
3339 default_addr_space_debug)
3341 /* Function to emit custom diagnostic if an address space is used. */
3344 "Define this hook if the availability of an address space depends on\n\
3345 command line options and some diagnostics should be printed when the\n\
3346 address space is used. This hook is called during parsing and allows\n\
3347 to emit a better diagnostic compared to the case where the address space\n\
3348 was not registered with @code{c_register_addr_space}. @var{as} is\n\
3349 the address space as registered with @code{c_register_addr_space}.\n\
3350 @var{loc} is the location of the address space qualifier token.\n\
3351 The default implementation does nothing.",
3352 void, (addr_space_t as, location_t loc),
3353 default_addr_space_diagnose_usage)
3355 HOOK_VECTOR_END (addr_space)
3358 #define HOOK_PREFIX "TARGET_"
3361 (lower_local_decl_alignment,
3362 "Define this hook to lower alignment of local, parm or result\n\
3363 decl @samp{(@var{decl})}.",
3368 (static_rtx_alignment,
3369 "This hook returns the preferred alignment in bits for a\n\
3370 statically-allocated rtx, such as a constant pool entry. @var{mode}\n\
3371 is the mode of the rtx. The default implementation returns\n\
3372 @samp{GET_MODE_ALIGNMENT (@var{mode})}.",
3373 HOST_WIDE_INT, (machine_mode mode),
3374 default_static_rtx_alignment)
3377 (constant_alignment,
3378 "This hook returns the alignment in bits of a constant that is being\n\
3379 placed in memory. @var{constant} is the constant and @var{basic_align}\n\
3380 is the alignment that the object would ordinarily have.\n\
3382 The default definition just returns @var{basic_align}.\n\
3384 The typical use of this hook is to increase alignment for string\n\
3385 constants to be word aligned so that @code{strcpy} calls that copy\n\
3386 constants can be done inline. The function\n\
3387 @code{constant_alignment_word_strings} provides such a definition.",
3388 HOST_WIDE_INT, (const_tree constant, HOST_WIDE_INT basic_align),
3389 default_constant_alignment)
3392 (translate_mode_attribute,
3393 "Define this hook if during mode attribute processing, the port should\n\
3394 translate machine_mode @var{mode} to another mode. For example, rs6000's\n\
3395 @code{KFmode}, when it is the same as @code{TFmode}.\n\
3397 The default version of the hook returns that mode that was passed in.",
3398 machine_mode, (machine_mode mode),
3399 default_translate_mode_attribute)
3401 /* True if MODE is valid for the target. By "valid", we mean able to
3402 be manipulated in non-trivial ways. In particular, this means all
3403 the arithmetic is supported. */
3405 (scalar_mode_supported_p,
3406 "Define this to return nonzero if the port is prepared to handle\n\
3407 insns involving scalar mode @var{mode}. For a scalar mode to be\n\
3408 considered supported, all the basic arithmetic and comparisons\n\
3411 The default version of this hook returns true for any mode\n\
3412 required to handle the basic C types (as defined by the port).\n\
3413 Included here are the double-word arithmetic supported by the\n\
3414 code in @file{optabs.c}.",
3415 bool, (scalar_mode mode),
3416 default_scalar_mode_supported_p)
3418 /* Similarly for vector modes. "Supported" here is less strict. At
3419 least some operations are supported; need to check optabs or builtins
3420 for further details. */
3422 (vector_mode_supported_p,
3423 "Define this to return nonzero if the port is prepared to handle\n\
3424 insns involving vector mode @var{mode}. At the very least, it\n\
3425 must have move patterns for this mode.",
3426 bool, (machine_mode mode),
3427 hook_bool_mode_false)
3430 (compatible_vector_types_p,
3431 "Return true if there is no target-specific reason for treating\n\
3432 vector types @var{type1} and @var{type2} as distinct types. The caller\n\
3433 has already checked for target-independent reasons, meaning that the\n\
3434 types are known to have the same mode, to have the same number of elements,\n\
3435 and to have what the caller considers to be compatible element types.\n\
3437 The main reason for defining this hook is to reject pairs of types\n\
3438 that are handled differently by the target's calling convention.\n\
3439 For example, when a new @var{N}-bit vector architecture is added\n\
3440 to a target, the target may want to handle normal @var{N}-bit\n\
3441 @code{VECTOR_TYPE} arguments and return values in the same way as\n\
3442 before, to maintain backwards compatibility. However, it may also\n\
3443 provide new, architecture-specific @code{VECTOR_TYPE}s that are passed\n\
3444 and returned in a more efficient way. It is then important to maintain\n\
3445 a distinction between the ``normal'' @code{VECTOR_TYPE}s and the new\n\
3446 architecture-specific ones.\n\
3448 The default implementation returns true, which is correct for most targets.",
3449 bool, (const_tree type1, const_tree type2),
3450 hook_bool_const_tree_const_tree_true)
3454 "This hook can be used to define the alignment for a vector of type\n\
3455 @var{type}, in order to comply with a platform ABI. The default is to\n\
3456 require natural alignment for vector types. The alignment returned by\n\
3457 this hook must be a power-of-two multiple of the default alignment of\n\
3458 the vector element type.",
3459 HOST_WIDE_INT, (const_tree type),
3460 default_vector_alignment)
3464 "Return the mode that GCC should use for an array that has\n\
3465 @var{nelems} elements, with each element having mode @var{mode}.\n\
3466 Return no mode if the target has no special requirements. In the\n\
3467 latter case, GCC looks for an integer mode of the appropriate size\n\
3468 if available and uses BLKmode otherwise. Usually the search for the\n\
3469 integer mode is limited to @code{MAX_FIXED_MODE_SIZE}, but the\n\
3470 @code{TARGET_ARRAY_MODE_SUPPORTED_P} hook allows a larger mode to be\n\
3471 used in specific cases.\n\
3473 The main use of this hook is to specify that an array of vectors should\n\
3474 also have a vector mode. The default implementation returns no mode.",
3475 opt_machine_mode, (machine_mode mode, unsigned HOST_WIDE_INT nelems),
3476 hook_optmode_mode_uhwi_none)
3478 /* True if we should try to use a scalar mode to represent an array,
3479 overriding the usual MAX_FIXED_MODE limit. */
3481 (array_mode_supported_p,
3482 "Return true if GCC should try to use a scalar mode to store an array\n\
3483 of @var{nelems} elements, given that each element has mode @var{mode}.\n\
3484 Returning true here overrides the usual @code{MAX_FIXED_MODE} limit\n\
3485 and allows GCC to use any defined integer mode.\n\
3487 One use of this hook is to support vector load and store operations\n\
3488 that operate on several homogeneous vectors. For example, ARM NEON\n\
3489 has operations like:\n\
3492 int8x8x3_t vld3_s8 (const int8_t *)\n\
3493 @end smallexample\n\
3495 where the return type is defined as:\n\
3498 typedef struct int8x8x3_t\n\
3502 @end smallexample\n\
3504 If this hook allows @code{val} to have a scalar mode, then\n\
3505 @code{int8x8x3_t} can have the same mode. GCC can then store\n\
3506 @code{int8x8x3_t}s in registers rather than forcing them onto the stack.",
3507 bool, (machine_mode mode, unsigned HOST_WIDE_INT nelems),
3508 hook_bool_mode_uhwi_false)
3511 (libgcc_floating_mode_supported_p,
3512 "Define this to return nonzero if libgcc provides support for the \n\
3513 floating-point mode @var{mode}, which is known to pass \n\
3514 @code{TARGET_SCALAR_MODE_SUPPORTED_P}. The default version of this \n\
3515 hook returns true for all of @code{SFmode}, @code{DFmode}, \n\
3516 @code{XFmode} and @code{TFmode}, if such modes exist.",
3517 bool, (scalar_float_mode mode),
3518 default_libgcc_floating_mode_supported_p)
3522 "Define this to return the machine mode to use for the type \n\
3523 @code{_Float@var{n}}, if @var{extended} is false, or the type \n\
3524 @code{_Float@var{n}x}, if @var{extended} is true. If such a type is not\n\
3525 supported, return @code{opt_scalar_float_mode ()}. The default version of\n\
3526 this hook returns @code{SFmode} for @code{_Float32}, @code{DFmode} for\n\
3527 @code{_Float64} and @code{_Float32x} and @code{TFmode} for \n\
3528 @code{_Float128}, if those modes exist and satisfy the requirements for \n\
3529 those types and pass @code{TARGET_SCALAR_MODE_SUPPORTED_P} and \n\
3530 @code{TARGET_LIBGCC_FLOATING_MODE_SUPPORTED_P}; for @code{_Float64x}, it \n\
3531 returns the first of @code{XFmode} and @code{TFmode} that exists and \n\
3532 satisfies the same requirements; for other types, it returns \n\
3533 @code{opt_scalar_float_mode ()}. The hook is only called for values\n\
3534 of @var{n} and @var{extended} that are valid according to\n\
3535 ISO/IEC TS 18661-3:2015; that is, @var{n} is one of 32, 64, 128, or,\n\
3536 if @var{extended} is false, 16 or greater than 128 and a multiple of 32.",
3537 opt_scalar_float_mode, (int n, bool extended),
3538 default_floatn_mode)
3542 "Define this to return true if the @code{_Float@var{n}} and\n\
3543 @code{_Float@var{n}x} built-in functions should implicitly enable the\n\
3544 built-in function without the @code{__builtin_} prefix in addition to the\n\
3545 normal built-in function with the @code{__builtin_} prefix. The default is\n\
3546 to only enable built-in functions without the @code{__builtin_} prefix for\n\
3547 the GNU C langauge. In strict ANSI/ISO mode, the built-in function without\n\
3548 the @code{__builtin_} prefix is not enabled. The argument @code{FUNC} is the\n\
3549 @code{enum built_in_function} id of the function to be enabled.",
3551 default_floatn_builtin_p)
3553 /* Compute cost of moving data from a register of class FROM to one of
3556 (register_move_cost,
3557 "This target hook should return the cost of moving data of mode @var{mode}\n\
3558 from a register in class @var{from} to one in class @var{to}. The classes\n\
3559 are expressed using the enumeration values such as @code{GENERAL_REGS}.\n\
3560 A value of 2 is the default; other values are interpreted relative to\n\
3563 It is not required that the cost always equal 2 when @var{from} is the\n\
3564 same as @var{to}; on some machines it is expensive to move between\n\
3565 registers if they are not general registers.\n\
3567 If reload sees an insn consisting of a single @code{set} between two\n\
3568 hard registers, and if @code{TARGET_REGISTER_MOVE_COST} applied to their\n\
3569 classes returns a value of 2, reload does not check to ensure that the\n\
3570 constraints of the insn are met. Setting a cost of other than 2 will\n\
3571 allow reload to verify that the constraints are met. You should do this\n\
3572 if the @samp{mov@var{m}} pattern's constraints do not allow such copying.\n\
3574 The default version of this function returns 2.",
3575 int, (machine_mode mode, reg_class_t from, reg_class_t to),
3576 default_register_move_cost)
3578 /* Compute cost of moving registers to/from memory. */
3579 /* ??? Documenting the argument types for this hook requires a GFDL
3580 license grant. Also, the documentation uses a different name for RCLASS. */
3583 "This target hook should return the cost of moving data of mode @var{mode}\n\
3584 between a register of class @var{rclass} and memory; @var{in} is @code{false}\n\
3585 if the value is to be written to memory, @code{true} if it is to be read in.\n\
3586 This cost is relative to those in @code{TARGET_REGISTER_MOVE_COST}.\n\
3587 If moving between registers and memory is more expensive than between two\n\
3588 registers, you should add this target hook to express the relative cost.\n\
3590 If you do not add this target hook, GCC uses a default cost of 4 plus\n\
3591 the cost of copying via a secondary reload register, if one is\n\
3592 needed. If your machine requires a secondary reload register to copy\n\
3593 between memory and a register of @var{rclass} but the reload mechanism is\n\
3594 more complex than copying via an intermediate, use this target hook to\n\
3595 reflect the actual cost of the move.\n\
3597 GCC defines the function @code{memory_move_secondary_cost} if\n\
3598 secondary reloads are needed. It computes the costs due to copying via\n\
3599 a secondary register. If your machine copies from memory using a\n\
3600 secondary register in the conventional way but the default base value of\n\
3601 4 is not correct for your machine, use this target hook to add some other\n\
3602 value to the result of that function. The arguments to that function\n\
3603 are the same as to this target hook.",
3604 int, (machine_mode mode, reg_class_t rclass, bool in),
3605 default_memory_move_cost)
3608 (use_by_pieces_infrastructure_p,
3609 "GCC will attempt several strategies when asked to copy between\n\
3610 two areas of memory, or to set, clear or store to memory, for example\n\
3611 when copying a @code{struct}. The @code{by_pieces} infrastructure\n\
3612 implements such memory operations as a sequence of load, store or move\n\
3613 insns. Alternate strategies are to expand the\n\
3614 @code{cpymem} or @code{setmem} optabs, to emit a library call, or to emit\n\
3615 unit-by-unit, loop-based operations.\n\
3617 This target hook should return true if, for a memory operation with a\n\
3618 given @var{size} and @var{alignment}, using the @code{by_pieces}\n\
3619 infrastructure is expected to result in better code generation.\n\
3620 Both @var{size} and @var{alignment} are measured in terms of storage\n\
3623 The parameter @var{op} is one of: @code{CLEAR_BY_PIECES},\n\
3624 @code{MOVE_BY_PIECES}, @code{SET_BY_PIECES}, @code{STORE_BY_PIECES} or\n\
3625 @code{COMPARE_BY_PIECES}. These describe the type of memory operation\n\
3626 under consideration.\n\
3628 The parameter @var{speed_p} is true if the code is currently being\n\
3629 optimized for speed rather than size.\n\
3631 Returning true for higher values of @var{size} can improve code generation\n\
3632 for speed if the target does not provide an implementation of the\n\
3633 @code{cpymem} or @code{setmem} standard names, if the @code{cpymem} or\n\
3634 @code{setmem} implementation would be more expensive than a sequence of\n\
3635 insns, or if the overhead of a library call would dominate that of\n\
3636 the body of the memory operation.\n\
3638 Returning true for higher values of @code{size} may also cause an increase\n\
3639 in code size, for example where the number of insns emitted to perform a\n\
3640 move would be greater than that of a library call.",
3641 bool, (unsigned HOST_WIDE_INT size, unsigned int alignment,
3642 enum by_pieces_operation op, bool speed_p),
3643 default_use_by_pieces_infrastructure_p)
3646 (overlap_op_by_pieces_p,
3647 "This target hook should return true if when the @code{by_pieces}\n\
3648 infrastructure is used, an offset adjusted unaligned memory operation\n\
3649 in the smallest integer mode for the last piece operation of a memory\n\
3650 region can be generated to avoid doing more than one smaller operations.",
3652 hook_bool_void_false)
3655 (compare_by_pieces_branch_ratio,
3656 "When expanding a block comparison in MODE, gcc can try to reduce the\n\
3657 number of branches at the expense of more memory operations. This hook\n\
3658 allows the target to override the default choice. It should return the\n\
3659 factor by which branches should be reduced over the plain expansion with\n\
3660 one comparison per @var{mode}-sized piece. A port can also prevent a\n\
3661 particular mode from being used for block comparisons by returning a\n\
3662 negative number from this hook.",
3663 int, (machine_mode mode),
3664 default_compare_by_pieces_branch_ratio)
3667 (slow_unaligned_access,
3668 "This hook returns true if memory accesses described by the\n\
3669 @var{mode} and @var{alignment} parameters have a cost many times greater\n\
3670 than aligned accesses, for example if they are emulated in a trap handler.\n\
3671 This hook is invoked only for unaligned accesses, i.e.@: when\n\
3672 @code{@var{alignment} < GET_MODE_ALIGNMENT (@var{mode})}.\n\
3674 When this hook returns true, the compiler will act as if\n\
3675 @code{STRICT_ALIGNMENT} were true when generating code for block\n\
3676 moves. This can cause significantly more instructions to be produced.\n\
3677 Therefore, do not make this hook return true if unaligned accesses only\n\
3678 add a cycle or two to the time for a memory access.\n\
3680 The hook must return true whenever @code{STRICT_ALIGNMENT} is true.\n\
3681 The default implementation returns @code{STRICT_ALIGNMENT}.",
3682 bool, (machine_mode mode, unsigned int align),
3683 default_slow_unaligned_access)
3687 "Return true if the optimizers should use optab @var{op} with\n\
3688 modes @var{mode1} and @var{mode2} for optimization type @var{opt_type}.\n\
3689 The optab is known to have an associated @file{.md} instruction\n\
3690 whose C condition is true. @var{mode2} is only meaningful for conversion\n\
3691 optabs; for direct optabs it is a copy of @var{mode1}.\n\
3693 For example, when called with @var{op} equal to @code{rint_optab} and\n\
3694 @var{mode1} equal to @code{DFmode}, the hook should say whether the\n\
3695 optimizers should use optab @code{rintdf2}.\n\
3697 The default hook returns true for all inputs.",
3698 bool, (int op, machine_mode mode1, machine_mode mode2,
3699 optimization_type opt_type),
3700 default_optab_supported_p)
3702 /* True for MODE if the target expects that registers in this mode will
3703 be allocated to registers in a small register class. The compiler is
3704 allowed to use registers explicitly used in the rtl as spill registers
3705 but it should prevent extending the lifetime of these registers. */
3707 (small_register_classes_for_mode_p,
3708 "Define this to return nonzero for machine modes for which the port has\n\
3709 small register classes. If this target hook returns nonzero for a given\n\
3710 @var{mode}, the compiler will try to minimize the lifetime of registers\n\
3711 in @var{mode}. The hook may be called with @code{VOIDmode} as argument.\n\
3712 In this case, the hook is expected to return nonzero if it returns nonzero\n\
3715 On some machines, it is risky to let hard registers live across arbitrary\n\
3716 insns. Typically, these machines have instructions that require values\n\
3717 to be in specific registers (like an accumulator), and reload will fail\n\
3718 if the required hard register is used for another purpose across such an\n\
3721 Passes before reload do not know which hard registers will be used\n\
3722 in an instruction, but the machine modes of the registers set or used in\n\
3723 the instruction are already known. And for some machines, register\n\
3724 classes are small for, say, integer registers but not for floating point\n\
3725 registers. For example, the AMD x86-64 architecture requires specific\n\
3726 registers for the legacy x86 integer instructions, but there are many\n\
3727 SSE registers for floating point operations. On such targets, a good\n\
3728 strategy may be to return nonzero from this hook for @code{INTEGRAL_MODE_P}\n\
3729 machine modes but zero for the SSE register classes.\n\
3731 The default version of this hook returns false for any mode. It is always\n\
3732 safe to redefine this hook to return with a nonzero value. But if you\n\
3733 unnecessarily define it, you will reduce the amount of optimizations\n\
3734 that can be performed in some cases. If you do not define this hook\n\
3735 to return a nonzero value when it is required, the compiler will run out\n\
3736 of spill registers and print a fatal error message.",
3737 bool, (machine_mode mode),
3738 hook_bool_mode_false)
3740 /* Register number for a flags register. Only needs to be defined if the
3741 target is constrainted to use post-reload comparison elimination. */
3744 "If the target has a dedicated flags register, and it needs to use the\n\
3745 post-reload comparison elimination pass, or the delay slot filler pass,\n\
3746 then this value should be set appropriately.",
3747 unsigned int, INVALID_REGNUM)
3749 /* Compute a (partial) cost for rtx X. Return true if the complete
3750 cost has been computed, and false if subexpressions should be
3751 scanned. In either case, *TOTAL contains the cost result. */
3752 /* Note that OUTER_CODE ought to be RTX_CODE, but that's
3753 not necessarily defined at this point. */
3756 "This target hook describes the relative costs of RTL expressions.\n\
3758 The cost may depend on the precise form of the expression, which is\n\
3759 available for examination in @var{x}, and the fact that @var{x} appears\n\
3760 as operand @var{opno} of an expression with rtx code @var{outer_code}.\n\
3761 That is, the hook can assume that there is some rtx @var{y} such\n\
3762 that @samp{GET_CODE (@var{y}) == @var{outer_code}} and such that\n\
3763 either (a) @samp{XEXP (@var{y}, @var{opno}) == @var{x}} or\n\
3764 (b) @samp{XVEC (@var{y}, @var{opno})} contains @var{x}.\n\
3766 @var{mode} is @var{x}'s machine mode, or for cases like @code{const_int} that\n\
3767 do not have a mode, the mode in which @var{x} is used.\n\
3769 In implementing this hook, you can use the construct\n\
3770 @code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3773 On entry to the hook, @code{*@var{total}} contains a default estimate\n\
3774 for the cost of the expression. The hook should modify this value as\n\
3775 necessary. Traditionally, the default costs are @code{COSTS_N_INSNS (5)}\n\
3776 for multiplications, @code{COSTS_N_INSNS (7)} for division and modulus\n\
3777 operations, and @code{COSTS_N_INSNS (1)} for all other operations.\n\
3779 When optimizing for code size, i.e.@: when @code{speed} is\n\
3780 false, this target hook should be used to estimate the relative\n\
3781 size cost of an expression, again relative to @code{COSTS_N_INSNS}.\n\
3783 The hook returns true when all subexpressions of @var{x} have been\n\
3784 processed, and false when @code{rtx_cost} should recurse.",
3785 bool, (rtx x, machine_mode mode, int outer_code, int opno, int *total, bool speed),
3786 hook_bool_rtx_mode_int_int_intp_bool_false)
3788 /* Compute the cost of X, used as an address. Never called with
3789 invalid addresses. */
3792 "This hook computes the cost of an addressing mode that contains\n\
3793 @var{address}. If not defined, the cost is computed from\n\
3794 the @var{address} expression and the @code{TARGET_RTX_COST} hook.\n\
3796 For most CISC machines, the default cost is a good approximation of the\n\
3797 true cost of the addressing mode. However, on RISC machines, all\n\
3798 instructions normally have the same length and execution time. Hence\n\
3799 all addresses will have equal costs.\n\
3801 In cases where more than one form of an address is known, the form with\n\
3802 the lowest cost will be used. If multiple forms have the same, lowest,\n\
3803 cost, the one that is the most complex will be used.\n\
3805 For example, suppose an address that is equal to the sum of a register\n\
3806 and a constant is used twice in the same basic block. When this macro\n\
3807 is not defined, the address will be computed in a register and memory\n\
3808 references will be indirect through that register. On machines where\n\
3809 the cost of the addressing mode containing the sum is no higher than\n\
3810 that of a simple indirect reference, this will produce an additional\n\
3811 instruction and possibly require an additional register. Proper\n\
3812 specification of this macro eliminates this overhead for such machines.\n\
3814 This hook is never called with an invalid address.\n\
3816 On machines where an address involving more than one register is as\n\
3817 cheap as an address computation involving only one register, defining\n\
3818 @code{TARGET_ADDRESS_COST} to reflect this can cause two registers to\n\
3819 be live over a region of code where only one would have been if\n\
3820 @code{TARGET_ADDRESS_COST} were not defined in that manner. This effect\n\
3821 should be considered in the definition of this macro. Equivalent costs\n\
3822 should probably only be given to addresses with different numbers of\n\
3823 registers on machines with lots of registers.",
3824 int, (rtx address, machine_mode mode, addr_space_t as, bool speed),
3825 default_address_cost)
3827 /* Compute a cost for INSN. */
3830 "This target hook describes the relative costs of RTL instructions.\n\
3832 In implementing this hook, you can use the construct\n\
3833 @code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3836 When optimizing for code size, i.e.@: when @code{speed} is\n\
3837 false, this target hook should be used to estimate the relative\n\
3838 size cost of an expression, again relative to @code{COSTS_N_INSNS}.",
3839 int, (rtx_insn *insn, bool speed), NULL)
3841 /* Give a cost, in RTX Costs units, for an edge. Like BRANCH_COST, but with
3842 well defined units. */
3844 (max_noce_ifcvt_seq_cost,
3845 "This hook returns a value in the same units as @code{TARGET_RTX_COSTS},\n\
3846 giving the maximum acceptable cost for a sequence generated by the RTL\n\
3847 if-conversion pass when conditional execution is not available.\n\
3848 The RTL if-conversion pass attempts to convert conditional operations\n\
3849 that would require a branch to a series of unconditional operations and\n\
3850 @code{mov@var{mode}cc} insns. This hook returns the maximum cost of the\n\
3851 unconditional instructions and the @code{mov@var{mode}cc} insns.\n\
3852 RTL if-conversion is cancelled if the cost of the converted sequence\n\
3853 is greater than the value returned by this hook.\n\
3855 @code{e} is the edge between the basic block containing the conditional\n\
3856 branch to the basic block which would be executed if the condition\n\
3859 The default implementation of this hook uses the\n\
3860 @code{max-rtl-if-conversion-[un]predictable} parameters if they are set,\n\
3861 and uses a multiple of @code{BRANCH_COST} otherwise.",
3862 unsigned int, (edge e),
3863 default_max_noce_ifcvt_seq_cost)
3865 /* Return true if the given instruction sequence is a good candidate
3866 as a replacement for the if-convertible sequence. */
3868 (noce_conversion_profitable_p,
3869 "This hook returns true if the instruction sequence @code{seq} is a good\n\
3870 candidate as a replacement for the if-convertible sequence described in\n\
3872 bool, (rtx_insn *seq, struct noce_if_info *if_info),
3873 default_noce_conversion_profitable_p)
3875 /* Return true if new_addr should be preferred over the existing address used by
3878 (new_address_profitable_p,
3879 "Return @code{true} if it is profitable to replace the address in\n\
3880 @var{memref} with @var{new_addr}. This allows targets to prevent the\n\
3881 scheduler from undoing address optimizations. The instruction containing the\n\
3882 memref is @var{insn}. The default implementation returns @code{true}.",
3883 bool, (rtx memref, rtx_insn * insn, rtx new_addr),
3884 default_new_address_profitable_p)
3887 (estimated_poly_value,
3888 "Return an estimate of the runtime value of @var{val}, for use in\n\
3889 things like cost calculations or profiling frequencies. @var{kind} is used\n\
3890 to ask for the minimum, maximum, and likely estimates of the value through\n\
3891 the @code{POLY_VALUE_MIN}, @code{POLY_VALUE_MAX} and\n\
3892 @code{POLY_VALUE_LIKELY} values. The default\n\
3893 implementation returns the lowest possible value of @var{val}.",
3894 HOST_WIDE_INT, (poly_int64 val, poly_value_estimate_kind kind),
3895 default_estimated_poly_value)
3897 /* Permit speculative instructions in delay slots during delayed-branch
3900 (no_speculation_in_delay_slots_p,
3901 "This predicate controls the use of the eager delay slot filler to disallow\n\
3902 speculatively executed instructions being placed in delay slots. Targets\n\
3903 such as certain MIPS architectures possess both branches with and without\n\
3904 delay slots. As the eager delay slot filler can decrease performance,\n\
3905 disabling it is beneficial when ordinary branches are available. Use of\n\
3906 delay slot branches filled using the basic filler is often still desirable\n\
3907 as the delay slot can hide a pipeline bubble.", bool, (void),
3908 hook_bool_void_false)
3910 /* Return where to allocate pseudo for a given hard register initial value. */
3912 (allocate_initial_value,
3914 When the initial value of a hard register has been copied in a pseudo\n\
3915 register, it is often not necessary to actually allocate another register\n\
3916 to this pseudo register, because the original hard register or a stack slot\n\
3917 it has been saved into can be used. @code{TARGET_ALLOCATE_INITIAL_VALUE}\n\
3918 is called at the start of register allocation once for each hard register\n\
3919 that had its initial value copied by using\n\
3920 @code{get_func_hard_reg_initial_val} or @code{get_hard_reg_initial_val}.\n\
3921 Possible values are @code{NULL_RTX}, if you don't want\n\
3922 to do any special allocation, a @code{REG} rtx---that would typically be\n\
3923 the hard register itself, if it is known not to be clobbered---or a\n\
3925 If you are returning a @code{MEM}, this is only a hint for the allocator;\n\
3926 it might decide to use another register anyways.\n\
3927 You may use @code{current_function_is_leaf} or \n\
3928 @code{REG_N_SETS} in the hook to determine if the hard\n\
3929 register in question will not be clobbered.\n\
3930 The default value of this hook is @code{NULL}, which disables any special\n\
3932 rtx, (rtx hard_reg), NULL)
3934 /* Return nonzero if evaluating UNSPEC X might cause a trap.
3935 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */
3938 "This target hook returns nonzero if @var{x}, an @code{unspec} or\n\
3939 @code{unspec_volatile} operation, might cause a trap. Targets can use\n\
3940 this hook to enhance precision of analysis for @code{unspec} and\n\
3941 @code{unspec_volatile} operations. You may call @code{may_trap_p_1}\n\
3942 to analyze inner elements of @var{x} in which case @var{flags} should be\n\
3944 int, (const_rtx x, unsigned flags),
3945 default_unspec_may_trap_p)
3947 /* Given a register, this hook should return a parallel of registers
3948 to represent where to find the register pieces. Define this hook
3949 if the register and its mode are represented in Dwarf in
3950 non-contiguous locations, or if the register should be
3951 represented in more than one register in Dwarf. Otherwise, this
3952 hook should return NULL_RTX. */
3954 (dwarf_register_span,
3955 "Given a register, this hook should return a parallel of registers to\n\
3956 represent where to find the register pieces. Define this hook if the\n\
3957 register and its mode are represented in Dwarf in non-contiguous\n\
3958 locations, or if the register should be represented in more than one\n\
3959 register in Dwarf. Otherwise, this hook should return @code{NULL_RTX}.\n\
3960 If not defined, the default is to return @code{NULL_RTX}.",
3964 /* Given a register return the mode of the corresponding DWARF frame
3967 (dwarf_frame_reg_mode,
3968 "Given a register, this hook should return the mode which the\n\
3969 corresponding Dwarf frame register should have. This is normally\n\
3970 used to return a smaller mode than the raw mode to prevent call\n\
3971 clobbered parts of a register altering the frame register size",
3972 machine_mode, (int regno),
3973 default_dwarf_frame_reg_mode)
3975 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
3976 entries not corresponding directly to registers below
3977 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
3978 code, given the address of the table. */
3980 (init_dwarf_reg_sizes_extra,
3981 "If some registers are represented in Dwarf-2 unwind information in\n\
3982 multiple pieces, define this hook to fill in information about the\n\
3983 sizes of those pieces in the table used by the unwinder at runtime.\n\
3984 It will be called by @code{expand_builtin_init_dwarf_reg_sizes} after\n\
3985 filling in a single size corresponding to each hard register;\n\
3986 @var{address} is the address of the table.",
3987 void, (tree address),
3990 /* Fetch the fixed register(s) which hold condition codes, for
3991 targets where it makes sense to look for duplicate assignments to
3992 the condition codes. This should return true if there is such a
3993 register, false otherwise. The arguments should be set to the
3994 fixed register numbers. Up to two condition code registers are
3995 supported. If there is only one for this target, the int pointed
3996 at by the second argument should be set to -1. */
3998 (fixed_condition_code_regs,
3999 "On targets which use a hard\n\
4000 register rather than a pseudo-register to hold condition codes, the\n\
4001 regular CSE passes are often not able to identify cases in which the\n\
4002 hard register is set to a common value. Use this hook to enable a\n\
4003 small pass which optimizes such cases. This hook should return true\n\
4004 to enable this pass, and it should set the integers to which its\n\
4005 arguments point to the hard register numbers used for condition codes.\n\
4006 When there is only one such register, as is true on most systems, the\n\
4007 integer pointed to by @var{p2} should be set to\n\
4008 @code{INVALID_REGNUM}.\n\
4010 The default version of this hook returns false.",
4011 bool, (unsigned int *p1, unsigned int *p2),
4012 hook_bool_uintp_uintp_false)
4014 /* If two condition code modes are compatible, return a condition
4015 code mode which is compatible with both, such that a comparison
4016 done in the returned mode will work for both of the original
4017 modes. If the condition code modes are not compatible, return
4020 (cc_modes_compatible,
4021 "On targets which use multiple condition code modes in class\n\
4022 @code{MODE_CC}, it is sometimes the case that a comparison can be\n\
4023 validly done in more than one mode. On such a system, define this\n\
4024 target hook to take two mode arguments and to return a mode in which\n\
4025 both comparisons may be validly done. If there is no such mode,\n\
4026 return @code{VOIDmode}.\n\
4028 The default version of this hook checks whether the modes are the\n\
4029 same. If they are, it returns that mode. If they are different, it\n\
4030 returns @code{VOIDmode}.",
4031 machine_mode, (machine_mode m1, machine_mode m2),
4032 default_cc_modes_compatible)
4034 /* Do machine-dependent code transformations. Called just before
4035 delayed-branch scheduling. */
4037 (machine_dependent_reorg,
4038 "If non-null, this hook performs a target-specific pass over the\n\
4039 instruction stream. The compiler will run it at all optimization levels,\n\
4040 just before the point at which it normally does delayed-branch scheduling.\n\
4042 The exact purpose of the hook varies from target to target. Some use\n\
4043 it to do transformations that are necessary for correctness, such as\n\
4044 laying out in-function constant pools or avoiding hardware hazards.\n\
4045 Others use it as an opportunity to do some machine-dependent optimizations.\n\
4047 You need not implement the hook if it has nothing to do. The default\n\
4048 definition is null.",
4051 /* Create the __builtin_va_list type. */
4053 (build_builtin_va_list,
4054 "This hook returns a type node for @code{va_list} for the target.\n\
4055 The default version of the hook returns @code{void*}.",
4057 std_build_builtin_va_list)
4059 /* Enumerate the va list variants. */
4062 "This target hook is used in function @code{c_common_nodes_and_builtins}\n\
4063 to iterate through the target specific builtin types for va_list. The\n\
4064 variable @var{idx} is used as iterator. @var{pname} has to be a pointer\n\
4065 to a @code{const char *} and @var{ptree} a pointer to a @code{tree} typed\n\
4067 The arguments @var{pname} and @var{ptree} are used to store the result of\n\
4068 this macro and are set to the name of the va_list builtin type and its\n\
4070 If the return value of this macro is zero, then there is no more element.\n\
4071 Otherwise the @var{IDX} should be increased for the next call of this\n\
4072 macro to iterate through all types.",
4073 int, (int idx, const char **pname, tree *ptree),
4076 /* Get the cfun/fndecl calling abi __builtin_va_list type. */
4079 "This hook returns the va_list type of the calling convention specified by\n\
4081 The default version of this hook returns @code{va_list_type_node}.",
4082 tree, (tree fndecl),
4085 /* Get the __builtin_va_list type dependent on input type. */
4087 (canonical_va_list_type,
4088 "This hook returns the va_list type of the calling convention specified by the\n\
4089 type of @var{type}. If @var{type} is not a valid va_list type, it returns\n\
4092 std_canonical_va_list_type)
4094 /* ??? Documenting this hook requires a GFDL license grant. */
4096 (expand_builtin_va_start,
4097 "Expand the @code{__builtin_va_start} builtin.",
4098 void, (tree valist, rtx nextarg), NULL)
4100 /* Gimplifies a VA_ARG_EXPR. */
4102 (gimplify_va_arg_expr,
4103 "This hook performs target-specific gimplification of\n\
4104 @code{VA_ARG_EXPR}. The first two parameters correspond to the\n\
4105 arguments to @code{va_arg}; the latter two are as in\n\
4106 @code{gimplify.c:gimplify_expr}.",
4107 tree, (tree valist, tree type, gimple_seq *pre_p, gimple_seq *post_p),
4108 std_gimplify_va_arg_expr)
4110 /* Validity-checking routines for PCH files, target-specific.
4111 get_pch_validity returns a pointer to the data to be stored,
4112 and stores the size in its argument. pch_valid_p gets the same
4113 information back and returns NULL if the PCH is valid,
4114 or an error message if not. */
4117 "This hook returns a pointer to the data needed by\n\
4118 @code{TARGET_PCH_VALID_P} and sets\n\
4119 @samp{*@var{sz}} to the size of the data in bytes.",
4120 void *, (size_t *sz),
4121 default_get_pch_validity)
4125 "This hook checks whether the options used to create a PCH file are\n\
4126 compatible with the current settings. It returns @code{NULL}\n\
4127 if so and a suitable error message if not. Error messages will\n\
4128 be presented to the user and must be localized using @samp{_(@var{msg})}.\n\
4130 @var{data} is the data that was returned by @code{TARGET_GET_PCH_VALIDITY}\n\
4131 when the PCH file was created and @var{sz} is the size of that data in bytes.\n\
4132 It's safe to assume that the data was created by the same version of the\n\
4133 compiler, so no format checking is needed.\n\
4135 The default definition of @code{default_pch_valid_p} should be\n\
4136 suitable for most targets.",
4137 const char *, (const void *data, size_t sz),
4138 default_pch_valid_p)
4142 "Called before writing out a PCH file. If the target has some\n\
4143 garbage-collected data that needs to be in a particular state on PCH loads,\n\
4144 it can use this hook to enforce that state. Very few targets need\n\
4145 to do anything here.",
4149 /* If nonnull, this function checks whether a PCH file with the
4150 given set of target flags can be used. It returns NULL if so,
4151 otherwise it returns an error message. */
4153 (check_pch_target_flags,
4154 "If this hook is nonnull, the default implementation of\n\
4155 @code{TARGET_PCH_VALID_P} will use it to check for compatible values\n\
4156 of @code{target_flags}. @var{pch_flags} specifies the value that\n\
4157 @code{target_flags} had when the PCH file was created. The return\n\
4158 value is the same as for @code{TARGET_PCH_VALID_P}.",
4159 const char *, (int pch_flags), NULL)
4161 /* True if the compiler should give an enum type only as many
4162 bytes as it takes to represent the range of possible values of
4165 (default_short_enums,
4166 "This target hook should return true if the compiler should give an\n\
4167 @code{enum} type only as many bytes as it takes to represent the range\n\
4168 of possible values of that type. It should return false if all\n\
4169 @code{enum} types should be allocated like @code{int}.\n\
4171 The default is to return false.",
4173 hook_bool_void_false)
4175 /* This target hook returns an rtx that is used to store the address
4176 of the current frame into the built-in setjmp buffer. */
4178 (builtin_setjmp_frame_value,
4179 "This target hook should return an rtx that is used to store\n\
4180 the address of the current frame into the built in @code{setjmp} buffer.\n\
4181 The default value, @code{virtual_stack_vars_rtx}, is correct for most\n\
4182 machines. One reason you may need to define this target hook is if\n\
4183 @code{hard_frame_pointer_rtx} is the appropriate value on your machine.",
4185 default_builtin_setjmp_frame_value)
4187 /* This target hook should manipulate the outputs, inputs, constraints,
4188 and clobbers the port wishes for pre-processing the asm. */
4191 "This target hook may add @dfn{clobbers} to @var{clobbers} and\n\
4192 @var{clobbered_regs} for any hard regs the port wishes to automatically\n\
4193 clobber for an asm. The @var{outputs} and @var{inputs} may be inspected\n\
4194 to avoid clobbering a register that is already used by the asm.\n\
4196 It may modify the @var{outputs}, @var{inputs}, @var{input_modes}, and\n\
4197 @var{constraints} as necessary for other pre-processing. In this case the\n\
4198 return value is a sequence of insns to emit after the asm. Note that\n\
4199 changes to @var{inputs} must be accompanied by the corresponding changes\n\
4200 to @var{input_modes}.",
4202 (vec<rtx>& outputs, vec<rtx>& inputs, vec<machine_mode>& input_modes,
4203 vec<const char *>& constraints, vec<rtx>& clobbers,
4204 HARD_REG_SET& clobbered_regs),
4207 /* This target hook allows the backend to specify a calling convention
4208 in the debug information. This function actually returns an
4209 enum dwarf_calling_convention, but because of forward declarations
4210 and not wanting to include dwarf2.h everywhere target.h is included
4211 the function is being declared as an int. */
4213 (dwarf_calling_convention,
4214 "Define this to enable the dwarf attribute @code{DW_AT_calling_convention} to\n\
4215 be emitted for each function. Instead of an integer return the enum\n\
4216 value for the @code{DW_CC_} tag.",
4217 int, (const_tree function),
4218 hook_int_const_tree_0)
4220 /* This target hook allows the backend to emit frame-related insns that
4221 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
4222 engine will invoke it on insns of the form
4223 (set (reg) (unspec [...] UNSPEC_INDEX))
4225 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
4226 to let the backend emit the call frame instructions. */
4228 (dwarf_handle_frame_unspec,
4229 "This target hook allows the backend to emit frame-related insns that\n\
4230 contain UNSPECs or UNSPEC_VOLATILEs. The DWARF 2 call frame debugging\n\
4231 info engine will invoke it on insns of the form\n\
4233 (set (reg) (unspec [@dots{}] UNSPEC_INDEX))\n\
4234 @end smallexample\n\
4237 (set (reg) (unspec_volatile [@dots{}] UNSPECV_INDEX)).\n\
4238 @end smallexample\n\
4239 to let the backend emit the call frame instructions. @var{label} is\n\
4240 the CFI label attached to the insn, @var{pattern} is the pattern of\n\
4241 the insn and @var{index} is @code{UNSPEC_INDEX} or @code{UNSPECV_INDEX}.",
4242 void, (const char *label, rtx pattern, int index), NULL)
4245 (dwarf_poly_indeterminate_value,
4246 "Express the value of @code{poly_int} indeterminate @var{i} as a DWARF\n\
4247 expression, with @var{i} counting from 1. Return the number of a DWARF\n\
4248 register @var{R} and set @samp{*@var{factor}} and @samp{*@var{offset}} such\n\
4249 that the value of the indeterminate is:\n\
4251 value_of(@var{R}) / @var{factor} - @var{offset}\n\
4252 @end smallexample\n\
4254 A target only needs to define this hook if it sets\n\
4255 @samp{NUM_POLY_INT_COEFFS} to a value greater than 1.",
4256 unsigned int, (unsigned int i, unsigned int *factor, int *offset),
4257 default_dwarf_poly_indeterminate_value)
4259 /* ??? Documenting this hook requires a GFDL license grant. */
4261 (stdarg_optimize_hook,
4262 "Perform architecture specific checking of statements gimplified\
4263 from @code{VA_ARG_EXPR}. @var{stmt} is the statement. Returns true if\
4264 the statement doesn't need to be checked for @code{va_list} references.",
4265 bool, (struct stdarg_info *ai, const gimple *stmt), NULL)
4267 /* This target hook allows the operating system to override the DECL
4268 that represents the external variable that contains the stack
4269 protection guard variable. The type of this DECL is ptr_type_node. */
4271 (stack_protect_guard,
4272 "This hook returns a @code{DECL} node for the external variable to use\n\
4273 for the stack protection guard. This variable is initialized by the\n\
4274 runtime to some random value and is used to initialize the guard value\n\
4275 that is placed at the top of the local stack frame. The type of this\n\
4276 variable must be @code{ptr_type_node}.\n\
4278 The default version of this hook creates a variable called\n\
4279 @samp{__stack_chk_guard}, which is normally defined in @file{libgcc2.c}.",
4281 default_stack_protect_guard)
4283 /* This target hook allows the operating system to override the CALL_EXPR
4284 that is invoked when a check vs the guard variable fails. */
4286 (stack_protect_fail,
4287 "This hook returns a @code{CALL_EXPR} that alerts the runtime that the\n\
4288 stack protect guard variable has been modified. This expression should\n\
4289 involve a call to a @code{noreturn} function.\n\
4291 The default version of this hook invokes a function called\n\
4292 @samp{__stack_chk_fail}, taking no arguments. This function is\n\
4293 normally defined in @file{libgcc2.c}.",
4295 default_external_stack_protect_fail)
4297 /* This target hook allows the operating system to disable the default stack
4298 protector runtime support. */
4300 (stack_protect_runtime_enabled_p,
4301 "Returns true if the target wants GCC's default stack protect runtime support,\
4302 otherwise return false. The default implementation always returns true.",
4304 hook_bool_void_true)
4307 (have_speculation_safe_value,
4308 "This hook is used to determine the level of target support for\n\
4309 @code{__builtin_speculation_safe_value}. If called with an argument\n\
4310 of false, it returns true if the target has been modified to support\n\
4311 this builtin. If called with an argument of true, it returns true\n\
4312 if the target requires active mitigation execution might be speculative.\n\
4314 The default implementation returns false if the target does not define\n\
4315 a pattern named @code{speculation_barrier}. Else it returns true\n\
4316 for the first case and whether the pattern is enabled for the current\n\
4317 compilation for the second case.\n\
4319 For targets that have no processors that can execute instructions\n\
4320 speculatively an alternative implemenation of this hook is available:\n\
4321 simply redefine this hook to @code{speculation_safe_value_not_needed}\n\
4322 along with your other target hooks.",
4323 bool, (bool active), default_have_speculation_safe_value)
4326 (speculation_safe_value,
4327 "This target hook can be used to generate a target-specific code\n\
4328 sequence that implements the @code{__builtin_speculation_safe_value}\n\
4329 built-in function. The function must always return @var{val} in\n\
4330 @var{result} in mode @var{mode} when the cpu is not executing\n\
4331 speculatively, but must never return that when speculating until it\n\
4332 is known that the speculation will not be unwound. The hook supports\n\
4333 two primary mechanisms for implementing the requirements. The first\n\
4334 is to emit a speculation barrier which forces the processor to wait\n\
4335 until all prior speculative operations have been resolved; the second\n\
4336 is to use a target-specific mechanism that can track the speculation\n\
4337 state and to return @var{failval} if it can determine that\n\
4338 speculation must be unwound at a later time.\n\
4340 The default implementation simply copies @var{val} to @var{result} and\n\
4341 emits a @code{speculation_barrier} instruction if that is defined.",
4342 rtx, (machine_mode mode, rtx result, rtx val, rtx failval),
4343 default_speculation_safe_value)
4347 "Return true if we can predict it is possible to use a low-overhead loop\n\
4348 for a particular loop. The parameter @var{loop} is a pointer to the loop.\n\
4349 This target hook is required only when the target supports low-overhead\n\
4350 loops, and will help ivopts to make some decisions.\n\
4351 The default version of this hook returns false.",
4352 bool, (class loop *loop),
4353 default_predict_doloop_p)
4356 (have_count_reg_decr_p,
4357 "Return true if the target supports hardware count register for decrement\n\
4359 The default value is false.",
4363 (doloop_cost_for_generic,
4364 "One IV candidate dedicated for doloop is introduced in IVOPTs, we can\n\
4365 calculate the computation cost of adopting it to any generic IV use by\n\
4366 function get_computation_cost as before. But for targets which have\n\
4367 hardware count register support for decrement and branch, it may have to\n\
4368 move IV value from hardware count register to general purpose register\n\
4369 while doloop IV candidate is used for generic IV uses. It probably takes\n\
4370 expensive penalty. This hook allows target owners to define the cost for\n\
4371 this especially for generic IV uses.\n\
4372 The default value is zero.",
4376 (doloop_cost_for_address,
4377 "One IV candidate dedicated for doloop is introduced in IVOPTs, we can\n\
4378 calculate the computation cost of adopting it to any address IV use by\n\
4379 function get_computation_cost as before. But for targets which have\n\
4380 hardware count register support for decrement and branch, it may have to\n\
4381 move IV value from hardware count register to general purpose register\n\
4382 while doloop IV candidate is used for address IV uses. It probably takes\n\
4383 expensive penalty. This hook allows target owners to define the cost for\n\
4384 this escpecially for address IV uses.\n\
4385 The default value is zero.",
4390 "Return true if it is possible to use low-overhead loops (@code{doloop_end}\n\
4391 and @code{doloop_begin}) for a particular loop. @var{iterations} gives the\n\
4392 exact number of iterations, or 0 if not known. @var{iterations_max} gives\n\
4393 the maximum number of iterations, or 0 if not known. @var{loop_depth} is\n\
4394 the nesting depth of the loop, with 1 for innermost loops, 2 for loops that\n\
4395 contain innermost loops, and so on. @var{entered_at_top} is true if the\n\
4396 loop is only entered from the top.\n\
4398 This hook is only used if @code{doloop_end} is available. The default\n\
4399 implementation returns true. You can use @code{can_use_doloop_if_innermost}\n\
4400 if the loop must be the innermost, and if there are no other restrictions.",
4401 bool, (const widest_int &iterations, const widest_int &iterations_max,
4402 unsigned int loop_depth, bool entered_at_top),
4403 hook_bool_wint_wint_uint_bool_true)
4405 /* Returns NULL if target supports the insn within a doloop block,
4406 otherwise it returns an error message. */
4408 (invalid_within_doloop,
4410 Take an instruction in @var{insn} and return NULL if it is valid within a\n\
4411 low-overhead loop, otherwise return a string explaining why doloop\n\
4412 could not be applied.\n\
4414 Many targets use special registers for low-overhead looping. For any\n\
4415 instruction that clobbers these this function should return a string indicating\n\
4416 the reason why the doloop could not be applied.\n\
4417 By default, the RTL loop optimizer does not use a present doloop pattern for\n\
4418 loops containing function calls or branch on table instructions.",
4419 const char *, (const rtx_insn *insn),
4420 default_invalid_within_doloop)
4422 /* Returns true for a legitimate combined insn. */
4424 (legitimate_combined_insn,
4425 "Take an instruction in @var{insn} and return @code{false} if the instruction\
4426 is not appropriate as a combination of two or more instructions. The\
4427 default is to accept all instructions.",
4428 bool, (rtx_insn *insn),
4429 hook_bool_rtx_insn_true)
4432 (valid_dllimport_attribute_p,
4433 "@var{decl} is a variable or function with @code{__attribute__((dllimport))}\
4434 specified. Use this hook if the target needs to add extra validation\
4435 checks to @code{handle_dll_attribute}.",
4436 bool, (const_tree decl),
4437 hook_bool_const_tree_true)
4439 /* If non-zero, align constant anchors in CSE to a multiple of this
4443 "On some architectures it can take multiple instructions to synthesize\n\
4444 a constant. If there is another constant already in a register that\n\
4445 is close enough in value then it is preferable that the new constant\n\
4446 is computed from this register using immediate addition or\n\
4447 subtraction. We accomplish this through CSE. Besides the value of\n\
4448 the constant we also add a lower and an upper constant anchor to the\n\
4449 available expressions. These are then queried when encountering new\n\
4450 constants. The anchors are computed by rounding the constant up and\n\
4451 down to a multiple of the value of @code{TARGET_CONST_ANCHOR}.\n\
4452 @code{TARGET_CONST_ANCHOR} should be the maximum positive value\n\
4453 accepted by immediate-add plus one. We currently assume that the\n\
4454 value of @code{TARGET_CONST_ANCHOR} is a power of 2. For example, on\n\
4455 MIPS, where add-immediate takes a 16-bit signed value,\n\
4456 @code{TARGET_CONST_ANCHOR} is set to @samp{0x8000}. The default value\n\
4457 is zero, which disables this optimization.",
4458 unsigned HOST_WIDE_INT, 0)
4460 /* Defines, which target-dependent bits (upper 16) are used by port */
4463 "Validate target specific memory model mask bits. When NULL no target specific\n\
4464 memory model bits are allowed.",
4465 unsigned HOST_WIDE_INT, (unsigned HOST_WIDE_INT val), NULL)
4467 /* Defines an offset bitwise ored into shifted address to get corresponding
4468 Address Sanitizer shadow address, or -1 if Address Sanitizer is not
4469 supported by the target. */
4471 (asan_shadow_offset,
4472 "Return the offset bitwise ored into shifted address to get corresponding\n\
4473 Address Sanitizer shadow memory address. NULL if Address Sanitizer is not\n\
4474 supported by the target. May return 0 if Address Sanitizer is not supported\n\
4476 unsigned HOST_WIDE_INT, (void),
4479 /* Functions relating to calls - argument passing, returns, etc. */
4480 /* Members of struct call have no special macro prefix. */
4481 HOOK_VECTOR (TARGET_CALLS, calls)
4484 (promote_function_mode,
4485 "Like @code{PROMOTE_MODE}, but it is applied to outgoing function arguments or\n\
4486 function return values. The target hook should return the new mode\n\
4487 and possibly change @code{*@var{punsignedp}} if the promotion should\n\
4488 change signedness. This function is called only for scalar @emph{or\n\
4491 @var{for_return} allows to distinguish the promotion of arguments and\n\
4492 return values. If it is @code{1}, a return value is being promoted and\n\
4493 @code{TARGET_FUNCTION_VALUE} must perform the same promotions done here.\n\
4494 If it is @code{2}, the returned mode should be that of the register in\n\
4495 which an incoming parameter is copied, or the outgoing result is computed;\n\
4496 then the hook should return the same mode as @code{promote_mode}, though\n\
4497 the signedness may be different.\n\
4499 @var{type} can be NULL when promoting function arguments of libcalls.\n\
4501 The default is to not promote arguments and return values. You can\n\
4502 also define the hook to @code{default_promote_function_mode_always_promote}\n\
4503 if you would like to apply the same rules given by @code{PROMOTE_MODE}.",
4504 machine_mode, (const_tree type, machine_mode mode, int *punsignedp,
4505 const_tree funtype, int for_return),
4506 default_promote_function_mode)
4509 (promote_prototypes,
4510 "This target hook returns @code{true} if an argument declared in a\n\
4511 prototype as an integral type smaller than @code{int} should actually be\n\
4512 passed as an @code{int}. In addition to avoiding errors in certain\n\
4513 cases of mismatch, it also makes for better code on certain machines.\n\
4514 The default is to not promote prototypes.",
4515 bool, (const_tree fntype),
4516 hook_bool_const_tree_false)
4520 "This target hook should return the location of the structure value\n\
4521 address (normally a @code{mem} or @code{reg}), or 0 if the address is\n\
4522 passed as an ``invisible'' first argument. Note that @var{fndecl} may\n\
4523 be @code{NULL}, for libcalls. You do not need to define this target\n\
4524 hook if the address is always passed as an ``invisible'' first\n\
4527 On some architectures the place where the structure value address\n\
4528 is found by the called function is not the same place that the\n\
4529 caller put it. This can be due to register windows, or it could\n\
4530 be because the function prologue moves it to a different place.\n\
4531 @var{incoming} is @code{1} or @code{2} when the location is needed in\n\
4532 the context of the called function, and @code{0} in the context of\n\
4535 If @var{incoming} is nonzero and the address is to be found on the\n\
4536 stack, return a @code{mem} which refers to the frame pointer. If\n\
4537 @var{incoming} is @code{2}, the result is being used to fetch the\n\
4538 structure value address at the beginning of a function. If you need\n\
4539 to emit adjusting code, you should do it at this point.",
4540 rtx, (tree fndecl, int incoming),
4541 hook_rtx_tree_int_null)
4544 (omit_struct_return_reg,
4545 "Normally, when a function returns a structure by memory, the address\n\
4546 is passed as an invisible pointer argument, but the compiler also\n\
4547 arranges to return the address from the function like it would a normal\n\
4548 pointer return value. Define this to true if that behavior is\n\
4549 undesirable on your target.",
4554 "This target hook should return a nonzero value to say to return the\n\
4555 function value in memory, just as large structures are always returned.\n\
4556 Here @var{type} will be the data type of the value, and @var{fntype}\n\
4557 will be the type of the function doing the returning, or @code{NULL} for\n\
4560 Note that values of mode @code{BLKmode} must be explicitly handled\n\
4561 by this function. Also, the option @option{-fpcc-struct-return}\n\
4562 takes effect regardless of this macro. On most systems, it is\n\
4563 possible to leave the hook undefined; this causes a default\n\
4564 definition to be used, whose value is the constant 1 for @code{BLKmode}\n\
4565 values, and 0 otherwise.\n\
4567 Do not use this hook to indicate that structures and unions should always\n\
4568 be returned in memory. You should instead use @code{DEFAULT_PCC_STRUCT_RETURN}\n\
4570 bool, (const_tree type, const_tree fntype),
4571 default_return_in_memory)
4575 "This hook should return true if values of type @var{type} are returned\n\
4576 at the most significant end of a register (in other words, if they are\n\
4577 padded at the least significant end). You can assume that @var{type}\n\
4578 is returned in a register; the caller is required to check this.\n\
4580 Note that the register provided by @code{TARGET_FUNCTION_VALUE} must\n\
4581 be able to hold the complete return value. For example, if a 1-, 2-\n\
4582 or 3-byte structure is returned at the most significant end of a\n\
4583 4-byte register, @code{TARGET_FUNCTION_VALUE} should provide an\n\
4584 @code{SImode} rtx.",
4585 bool, (const_tree type),
4586 hook_bool_const_tree_false)
4588 /* Return true if a parameter must be passed by reference. TYPE may
4589 be null if this is a libcall. CA may be null if this query is
4590 from __builtin_va_arg. */
4593 "This target hook should return @code{true} if argument @var{arg} at the\n\
4594 position indicated by @var{cum} should be passed by reference. This\n\
4595 predicate is queried after target independent reasons for being\n\
4596 passed by reference, such as @code{TREE_ADDRESSABLE (@var{arg}.type)}.\n\
4598 If the hook returns true, a copy of that argument is made in memory and a\n\
4599 pointer to the argument is passed instead of the argument itself.\n\
4600 The pointer is passed in whatever way is appropriate for passing a pointer\n\
4603 (cumulative_args_t cum, const function_arg_info &arg),
4604 hook_bool_CUMULATIVE_ARGS_arg_info_false)
4607 (expand_builtin_saveregs,
4608 "If defined, this hook produces the machine-specific code for a call to\n\
4609 @code{__builtin_saveregs}. This code will be moved to the very\n\
4610 beginning of the function, before any parameter access are made. The\n\
4611 return value of this function should be an RTX that contains the value\n\
4612 to use as the return of @code{__builtin_saveregs}.",
4614 default_expand_builtin_saveregs)
4616 /* Returns pretend_argument_size. */
4618 (setup_incoming_varargs,
4619 "This target hook offers an alternative to using\n\
4620 @code{__builtin_saveregs} and defining the hook\n\
4621 @code{TARGET_EXPAND_BUILTIN_SAVEREGS}. Use it to store the anonymous\n\
4622 register arguments into the stack so that all the arguments appear to\n\
4623 have been passed consecutively on the stack. Once this is done, you can\n\
4624 use the standard implementation of varargs that works for machines that\n\
4625 pass all their arguments on the stack.\n\
4627 The argument @var{args_so_far} points to the @code{CUMULATIVE_ARGS} data\n\
4628 structure, containing the values that are obtained after processing the\n\
4629 named arguments. The argument @var{arg} describes the last of these named\n\
4632 The target hook should do two things: first, push onto the stack all the\n\
4633 argument registers @emph{not} used for the named arguments, and second,\n\
4634 store the size of the data thus pushed into the @code{int}-valued\n\
4635 variable pointed to by @var{pretend_args_size}. The value that you\n\
4636 store here will serve as additional offset for setting up the stack\n\
4639 Because you must generate code to push the anonymous arguments at\n\
4640 compile time without knowing their data types,\n\
4641 @code{TARGET_SETUP_INCOMING_VARARGS} is only useful on machines that\n\
4642 have just a single category of argument register and use it uniformly\n\
4643 for all data types.\n\
4645 If the argument @var{second_time} is nonzero, it means that the\n\
4646 arguments of the function are being analyzed for the second time. This\n\
4647 happens for an inline function, which is not actually compiled until the\n\
4648 end of the source file. The hook @code{TARGET_SETUP_INCOMING_VARARGS} should\n\
4649 not generate any instructions in this case.",
4650 void, (cumulative_args_t args_so_far, const function_arg_info &arg,
4651 int *pretend_args_size, int second_time),
4652 default_setup_incoming_varargs)
4655 (load_bounds_for_arg,
4656 "This hook is used by expand pass to emit insn to load bounds of\n\
4657 @var{arg} passed in @var{slot}. Expand pass uses this hook in case\n\
4658 bounds of @var{arg} are not passed in register. If @var{slot} is a\n\
4659 memory, then bounds are loaded as for regular pointer loaded from\n\
4660 memory. If @var{slot} is not a memory then @var{slot_no} is an integer\n\
4661 constant holding number of the target dependent special slot which\n\
4662 should be used to obtain bounds. Hook returns RTX holding loaded bounds.",
4663 rtx, (rtx slot, rtx arg, rtx slot_no),
4664 default_load_bounds_for_arg)
4667 (store_bounds_for_arg,
4668 "This hook is used by expand pass to emit insns to store @var{bounds} of\n\
4669 @var{arg} passed in @var{slot}. Expand pass uses this hook in case\n\
4670 @var{bounds} of @var{arg} are not passed in register. If @var{slot} is a\n\
4671 memory, then @var{bounds} are stored as for regular pointer stored in\n\
4672 memory. If @var{slot} is not a memory then @var{slot_no} is an integer\n\
4673 constant holding number of the target dependent special slot which\n\
4674 should be used to store @var{bounds}.",
4675 void, (rtx arg, rtx slot, rtx bounds, rtx slot_no),
4676 default_store_bounds_for_arg)
4679 (load_returned_bounds,
4680 "This hook is used by expand pass to emit insn to load bounds\n\
4681 returned by function call in @var{slot}. Hook returns RTX holding\n\
4684 default_load_returned_bounds)
4687 (store_returned_bounds,
4688 "This hook is used by expand pass to emit insn to store @var{bounds}\n\
4689 returned by function call into @var{slot}.",
4690 void, (rtx slot, rtx bounds),
4691 default_store_returned_bounds)
4695 "While generating RTL for a function call, this target hook is invoked once\n\
4696 for each argument passed to the function, either a register returned by\n\
4697 @code{TARGET_FUNCTION_ARG} or a memory location. It is called just\n\
4698 before the point where argument registers are stored. The type of the\n\
4699 function to be called is also passed as the second argument; it is\n\
4700 @code{NULL_TREE} for libcalls. The @code{TARGET_END_CALL_ARGS} hook is\n\
4701 invoked just after the code to copy the return reg has been emitted.\n\
4702 This functionality can be used to perform special setup of call argument\n\
4703 registers if a target needs it.\n\
4704 For functions without arguments, the hook is called once with @code{pc_rtx}\n\
4705 passed instead of an argument register.\n\
4706 Most ports do not need to implement anything for this hook.",
4712 "This target hook is invoked while generating RTL for a function call,\n\
4713 just after the point where the return reg is copied into a pseudo. It\n\
4714 signals that all the call argument and return registers for the just\n\
4715 emitted call are now no longer in use.\n\
4716 Most ports do not need to implement anything for this hook.",
4721 (strict_argument_naming,
4722 "Define this hook to return @code{true} if the location where a function\n\
4723 argument is passed depends on whether or not it is a named argument.\n\
4725 This hook controls how the @var{named} argument to @code{TARGET_FUNCTION_ARG}\n\
4726 is set for varargs and stdarg functions. If this hook returns\n\
4727 @code{true}, the @var{named} argument is always true for named\n\
4728 arguments, and false for unnamed arguments. If it returns @code{false},\n\
4729 but @code{TARGET_PRETEND_OUTGOING_VARARGS_NAMED} returns @code{true},\n\
4730 then all arguments are treated as named. Otherwise, all named arguments\n\
4731 except the last are treated as named.\n\
4733 You need not define this hook if it always returns @code{false}.",
4734 bool, (cumulative_args_t ca),
4735 hook_bool_CUMULATIVE_ARGS_false)
4737 /* Returns true if we should use
4738 targetm.calls.setup_incoming_varargs() and/or
4739 targetm.calls.strict_argument_naming(). */
4741 (pretend_outgoing_varargs_named,
4742 "If you need to conditionally change ABIs so that one works with\n\
4743 @code{TARGET_SETUP_INCOMING_VARARGS}, but the other works like neither\n\
4744 @code{TARGET_SETUP_INCOMING_VARARGS} nor @code{TARGET_STRICT_ARGUMENT_NAMING} was\n\
4745 defined, then define this hook to return @code{true} if\n\
4746 @code{TARGET_SETUP_INCOMING_VARARGS} is used, @code{false} otherwise.\n\
4747 Otherwise, you should not define this hook.",
4748 bool, (cumulative_args_t ca),
4749 default_pretend_outgoing_varargs_named)
4751 /* Given a complex type T, return true if a parameter of type T
4752 should be passed as two scalars. */
4755 "This hook should return true if parameter of type @var{type} are passed\n\
4756 as two scalar parameters. By default, GCC will attempt to pack complex\n\
4757 arguments into the target's word size. Some ABIs require complex arguments\n\
4758 to be split and treated as their individual components. For example, on\n\
4759 AIX64, complex floats should be passed in a pair of floating point\n\
4760 registers, even though a complex float would fit in one 64-bit floating\n\
4763 The default value of this hook is @code{NULL}, which is treated as always\n\
4765 bool, (const_tree type), NULL)
4767 /* Return true if type T, mode MODE, may not be passed in registers,
4768 but must be passed on the stack. */
4769 /* ??? This predicate should be applied strictly after pass-by-reference.
4770 Need audit to verify that this is the case. */
4772 (must_pass_in_stack,
4773 "This target hook should return @code{true} if we should not pass @var{arg}\n\
4774 solely in registers. The file @file{expr.h} defines a\n\
4775 definition that is usually appropriate, refer to @file{expr.h} for additional\n\
4777 bool, (const function_arg_info &arg),
4778 must_pass_in_stack_var_size_or_pad)
4780 /* Return true if type TYPE, mode MODE, which is passed by reference,
4781 should have the object copy generated by the callee rather than
4782 the caller. It is never called for TYPE requiring constructors. */
4785 "The function argument described by the parameters to this hook is\n\
4786 known to be passed by reference. The hook should return true if the\n\
4787 function argument should be copied by the callee instead of copied\n\
4790 For any argument for which the hook returns true, if it can be\n\
4791 determined that the argument is not modified, then a copy need\n\
4792 not be generated.\n\
4794 The default version of this hook always returns false.",
4796 (cumulative_args_t cum, const function_arg_info &arg),
4797 hook_bool_CUMULATIVE_ARGS_arg_info_false)
4799 /* Return zero for arguments passed entirely on the stack or entirely
4800 in registers. If passed in both, return the number of bytes passed
4801 in registers; the balance is therefore passed on the stack. */
4804 "This target hook returns the number of bytes at the beginning of an\n\
4805 argument that must be put in registers. The value must be zero for\n\
4806 arguments that are passed entirely in registers or that are entirely\n\
4807 pushed on the stack.\n\
4809 On some machines, certain arguments must be passed partially in\n\
4810 registers and partially in memory. On these machines, typically the\n\
4811 first few words of arguments are passed in registers, and the rest\n\
4812 on the stack. If a multi-word argument (a @code{double} or a\n\
4813 structure) crosses that boundary, its first few words must be passed\n\
4814 in registers and the rest must be pushed. This macro tells the\n\
4815 compiler when this occurs, and how many bytes should go in registers.\n\
4817 @code{TARGET_FUNCTION_ARG} for these arguments should return the first\n\
4818 register to be used by the caller for this argument; likewise\n\
4819 @code{TARGET_FUNCTION_INCOMING_ARG}, for the called function.",
4820 int, (cumulative_args_t cum, const function_arg_info &arg),
4821 hook_int_CUMULATIVE_ARGS_arg_info_0)
4823 /* Update the state in CA to advance past an argument in the
4824 argument list. The values MODE, TYPE, and NAMED describe that
4827 (function_arg_advance,
4828 "This hook updates the summarizer variable pointed to by @var{ca} to\n\
4829 advance past argument @var{arg} in the argument list. Once this is done,\n\
4830 the variable @var{cum} is suitable for analyzing the @emph{following}\n\
4831 argument with @code{TARGET_FUNCTION_ARG}, etc.\n\
4833 This hook need not do anything if the argument in question was passed\n\
4834 on the stack. The compiler knows how to track the amount of stack space\n\
4835 used for arguments without any special help.",
4837 (cumulative_args_t ca, const function_arg_info &arg),
4838 default_function_arg_advance)
4841 (function_arg_offset,
4842 "This hook returns the number of bytes to add to the offset of an\n\
4843 argument of type @var{type} and mode @var{mode} when passed in memory.\n\
4844 This is needed for the SPU, which passes @code{char} and @code{short}\n\
4845 arguments in the preferred slot that is in the middle of the quad word\n\
4846 instead of starting at the top. The default implementation returns 0.",
4847 HOST_WIDE_INT, (machine_mode mode, const_tree type),
4848 default_function_arg_offset)
4851 (function_arg_padding,
4852 "This hook determines whether, and in which direction, to pad out\n\
4853 an argument of mode @var{mode} and type @var{type}. It returns\n\
4854 @code{PAD_UPWARD} to insert padding above the argument, @code{PAD_DOWNWARD}\n\
4855 to insert padding below the argument, or @code{PAD_NONE} to inhibit padding.\n\
4857 The @emph{amount} of padding is not controlled by this hook, but by\n\
4858 @code{TARGET_FUNCTION_ARG_ROUND_BOUNDARY}. It is always just enough\n\
4859 to reach the next multiple of that boundary.\n\
4861 This hook has a default definition that is right for most systems.\n\
4862 For little-endian machines, the default is to pad upward. For\n\
4863 big-endian machines, the default is to pad downward for an argument of\n\
4864 constant size shorter than an @code{int}, and upward otherwise.",
4865 pad_direction, (machine_mode mode, const_tree type),
4866 default_function_arg_padding)
4868 /* Return zero if the argument described by the state of CA should
4869 be placed on a stack, or a hard register in which to store the
4870 argument. The values MODE, TYPE, and NAMED describe that
4874 "Return an RTX indicating whether function argument @var{arg} is passed\n\
4875 in a register and if so, which register. Argument @var{ca} summarizes all\n\
4876 the previous arguments.\n\
4878 The return value is usually either a @code{reg} RTX for the hard\n\
4879 register in which to pass the argument, or zero to pass the argument\n\
4882 The return value can be a @code{const_int} which means argument is\n\
4883 passed in a target specific slot with specified number. Target hooks\n\
4884 should be used to store or load argument in such case. See\n\
4885 @code{TARGET_STORE_BOUNDS_FOR_ARG} and @code{TARGET_LOAD_BOUNDS_FOR_ARG}\n\
4886 for more information.\n\
4888 The value of the expression can also be a @code{parallel} RTX@. This is\n\
4889 used when an argument is passed in multiple locations. The mode of the\n\
4890 @code{parallel} should be the mode of the entire argument. The\n\
4891 @code{parallel} holds any number of @code{expr_list} pairs; each one\n\
4892 describes where part of the argument is passed. In each\n\
4893 @code{expr_list} the first operand must be a @code{reg} RTX for the hard\n\
4894 register in which to pass this part of the argument, and the mode of the\n\
4895 register RTX indicates how large this part of the argument is. The\n\
4896 second operand of the @code{expr_list} is a @code{const_int} which gives\n\
4897 the offset in bytes into the entire argument of where this part starts.\n\
4898 As a special exception the first @code{expr_list} in the @code{parallel}\n\
4899 RTX may have a first operand of zero. This indicates that the entire\n\
4900 argument is also stored on the stack.\n\
4902 The last time this hook is called, it is called with @code{MODE ==\n\
4903 VOIDmode}, and its result is passed to the @code{call} or @code{call_value}\n\
4904 pattern as operands 2 and 3 respectively.\n\
4906 @cindex @file{stdarg.h} and register arguments\n\
4907 The usual way to make the ISO library @file{stdarg.h} work on a\n\
4908 machine where some arguments are usually passed in registers, is to\n\
4909 cause nameless arguments to be passed on the stack instead. This is\n\
4910 done by making @code{TARGET_FUNCTION_ARG} return 0 whenever\n\
4911 @var{named} is @code{false}.\n\
4913 @cindex @code{TARGET_MUST_PASS_IN_STACK}, and @code{TARGET_FUNCTION_ARG}\n\
4914 @cindex @code{REG_PARM_STACK_SPACE}, and @code{TARGET_FUNCTION_ARG}\n\
4915 You may use the hook @code{targetm.calls.must_pass_in_stack}\n\
4916 in the definition of this macro to determine if this argument is of a\n\
4917 type that must be passed in the stack. If @code{REG_PARM_STACK_SPACE}\n\
4918 is not defined and @code{TARGET_FUNCTION_ARG} returns nonzero for such an\n\
4919 argument, the compiler will abort. If @code{REG_PARM_STACK_SPACE} is\n\
4920 defined, the argument will be computed in the stack and then loaded into\n\
4922 rtx, (cumulative_args_t ca, const function_arg_info &arg),
4923 default_function_arg)
4926 (function_incoming_arg,
4927 "Define this hook if the caller and callee on the target have different\n\
4928 views of where arguments are passed. Also define this hook if there are\n\
4929 functions that are never directly called, but are invoked by the hardware\n\
4930 and which have nonstandard calling conventions.\n\
4932 In this case @code{TARGET_FUNCTION_ARG} computes the register in\n\
4933 which the caller passes the value, and\n\
4934 @code{TARGET_FUNCTION_INCOMING_ARG} should be defined in a similar\n\
4935 fashion to tell the function being called where the arguments will\n\
4938 @code{TARGET_FUNCTION_INCOMING_ARG} can also return arbitrary address\n\
4939 computation using hard register, which can be forced into a register,\n\
4940 so that it can be used to pass special arguments.\n\
4942 If @code{TARGET_FUNCTION_INCOMING_ARG} is not defined,\n\
4943 @code{TARGET_FUNCTION_ARG} serves both purposes.",
4944 rtx, (cumulative_args_t ca, const function_arg_info &arg),
4945 default_function_incoming_arg)
4948 (function_arg_boundary,
4949 "This hook returns the alignment boundary, in bits, of an argument\n\
4950 with the specified mode and type. The default hook returns\n\
4951 @code{PARM_BOUNDARY} for all arguments.",
4952 unsigned int, (machine_mode mode, const_tree type),
4953 default_function_arg_boundary)
4956 (function_arg_round_boundary,
4957 "Normally, the size of an argument is rounded up to @code{PARM_BOUNDARY},\n\
4958 which is the default value for this hook. You can define this hook to\n\
4959 return a different value if an argument size must be rounded to a larger\n\
4961 unsigned int, (machine_mode mode, const_tree type),
4962 default_function_arg_round_boundary)
4964 /* Return the diagnostic message string if function without a prototype
4965 is not allowed for this 'val' argument; NULL otherwise. */
4967 (invalid_arg_for_unprototyped_fn,
4968 "If defined, this macro returns the diagnostic message when it is\n\
4969 illegal to pass argument @var{val} to function @var{funcdecl}\n\
4970 with prototype @var{typelist}.",
4971 const char *, (const_tree typelist, const_tree funcdecl, const_tree val),
4972 hook_invalid_arg_for_unprototyped_fn)
4974 /* Return an rtx for the return value location of the function
4975 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
4979 Define this to return an RTX representing the place where a function\n\
4980 returns or receives a value of data type @var{ret_type}, a tree node\n\
4981 representing a data type. @var{fn_decl_or_type} is a tree node\n\
4982 representing @code{FUNCTION_DECL} or @code{FUNCTION_TYPE} of a\n\
4983 function being called. If @var{outgoing} is false, the hook should\n\
4984 compute the register in which the caller will see the return value.\n\
4985 Otherwise, the hook should return an RTX representing the place where\n\
4986 a function returns a value.\n\
4988 On many machines, only @code{TYPE_MODE (@var{ret_type})} is relevant.\n\
4989 (Actually, on most machines, scalar values are returned in the same\n\
4990 place regardless of mode.) The value of the expression is usually a\n\
4991 @code{reg} RTX for the hard register where the return value is stored.\n\
4992 The value can also be a @code{parallel} RTX, if the return value is in\n\
4993 multiple places. See @code{TARGET_FUNCTION_ARG} for an explanation of the\n\
4994 @code{parallel} form. Note that the callee will populate every\n\
4995 location specified in the @code{parallel}, but if the first element of\n\
4996 the @code{parallel} contains the whole return value, callers will use\n\
4997 that element as the canonical location and ignore the others. The m68k\n\
4998 port uses this type of @code{parallel} to return pointers in both\n\
4999 @samp{%a0} (the canonical location) and @samp{%d0}.\n\
5001 If @code{TARGET_PROMOTE_FUNCTION_RETURN} returns true, you must apply\n\
5002 the same promotion rules specified in @code{PROMOTE_MODE} if\n\
5003 @var{valtype} is a scalar type.\n\
5005 If the precise function being called is known, @var{func} is a tree\n\
5006 node (@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null\n\
5007 pointer. This makes it possible to use a different value-returning\n\
5008 convention for specific functions when all their calls are\n\
5011 Some target machines have ``register windows'' so that the register in\n\
5012 which a function returns its value is not the same as the one in which\n\
5013 the caller sees the value. For such machines, you should return\n\
5014 different RTX depending on @var{outgoing}.\n\
5016 @code{TARGET_FUNCTION_VALUE} is not used for return values with\n\
5017 aggregate data types, because these are returned in another way. See\n\
5018 @code{TARGET_STRUCT_VALUE_RTX} and related macros, below.",
5019 rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
5020 default_function_value)
5022 /* Return the rtx for the result of a libcall of mode MODE,
5023 calling the function FN_NAME. */
5026 "Define this hook if the back-end needs to know the name of the libcall\n\
5027 function in order to determine where the result should be returned.\n\
5029 The mode of the result is given by @var{mode} and the name of the called\n\
5030 library function is given by @var{fun}. The hook should return an RTX\n\
5031 representing the place where the library function result will be returned.\n\
5033 If this hook is not defined, then LIBCALL_VALUE will be used.",
5034 rtx, (machine_mode mode, const_rtx fun),
5035 default_libcall_value)
5037 /* Return true if REGNO is a possible register number for
5038 a function value as seen by the caller. */
5040 (function_value_regno_p,
5041 "A target hook that return @code{true} if @var{regno} is the number of a hard\n\
5042 register in which the values of called function may come back.\n\
5044 A register whose use for returning values is limited to serving as the\n\
5045 second of a pair (for a value of type @code{double}, say) need not be\n\
5046 recognized by this target hook.\n\
5048 If the machine has register windows, so that the caller and the called\n\
5049 function use different registers for the return value, this target hook\n\
5050 should recognize only the caller's register numbers.\n\
5052 If this hook is not defined, then FUNCTION_VALUE_REGNO_P will be used.",
5053 bool, (const unsigned int regno),
5054 default_function_value_regno_p)
5058 "Return the ABI used by a function with type @var{type}; see the\n\
5059 definition of @code{predefined_function_abi} for details of the ABI\n\
5060 descriptor. Targets only need to define this hook if they support\n\
5061 interoperability between several ABIs in the same translation unit.",
5062 const predefined_function_abi &, (const_tree type),
5067 "This hook returns a description of the ABI used by the target of\n\
5068 call instruction @var{insn}; see the definition of\n\
5069 @code{predefined_function_abi} for details of the ABI descriptor.\n\
5070 Only the global function @code{insn_callee_abi} should call this hook\n\
5073 Targets only need to define this hook if they support\n\
5074 interoperability between several ABIs in the same translation unit.",
5075 const predefined_function_abi &, (const rtx_insn *insn),
5078 /* ??? Documenting this hook requires a GFDL license grant. */
5080 (internal_arg_pointer,
5081 "Return an rtx for the argument pointer incoming to the\
5084 default_internal_arg_pointer)
5086 /* Update the current function stack boundary if needed. */
5088 (update_stack_boundary,
5089 "Define this macro to update the current function stack boundary if\n\
5093 /* Handle stack alignment and return an rtx for Dynamic Realign
5094 Argument Pointer if necessary. */
5097 "This hook should return an rtx for Dynamic Realign Argument Pointer (DRAP) if a\n\
5098 different argument pointer register is needed to access the function's\n\
5099 argument list due to stack realignment. Return @code{NULL} if no DRAP\n\
5103 /* Generate instruction sequence to zero call used registers. */
5105 (zero_call_used_regs,
5106 "This target hook emits instructions to zero the subset of @var{selected_regs}\n\
5107 that could conceivably contain values that are useful to an attacker.\n\
5108 Return the set of registers that were actually cleared.\n\
5110 The default implementation uses normal move instructions to zero\n\
5111 all the registers in @var{selected_regs}. Define this hook if the\n\
5112 target has more efficient ways of zeroing certain registers,\n\
5113 or if you believe that certain registers would never contain\n\
5114 values that are useful to an attacker.",
5115 HARD_REG_SET, (HARD_REG_SET selected_regs),
5116 default_zero_call_used_regs)
5118 /* Return true if all function parameters should be spilled to the
5121 (allocate_stack_slots_for_args,
5122 "When optimization is disabled, this hook indicates whether or not\n\
5123 arguments should be allocated to stack slots. Normally, GCC allocates\n\
5124 stacks slots for arguments when not optimizing in order to make\n\
5125 debugging easier. However, when a function is declared with\n\
5126 @code{__attribute__((naked))}, there is no stack frame, and the compiler\n\
5127 cannot safely move arguments from the registers in which they are passed\n\
5128 to the stack. Therefore, this hook should return true in general, but\n\
5129 false for naked functions. The default implementation always returns true.",
5131 hook_bool_void_true)
5133 /* Return an rtx for the static chain for FNDECL_OR_TYPE. If INCOMING_P
5134 is true, then it should be for the callee; otherwise for the caller. */
5137 "This hook replaces the use of @code{STATIC_CHAIN_REGNUM} et al for\n\
5138 targets that may use different static chain locations for different\n\
5139 nested functions. This may be required if the target has function\n\
5140 attributes that affect the calling conventions of the function and\n\
5141 those calling conventions use different static chain locations.\n\
5143 The default version of this hook uses @code{STATIC_CHAIN_REGNUM} et al.\n\
5145 If the static chain is passed in memory, this hook should be used to\n\
5146 provide rtx giving @code{mem} expressions that denote where they are stored.\n\
5147 Often the @code{mem} expression as seen by the caller will be at an offset\n\
5148 from the stack pointer and the @code{mem} expression as seen by the callee\n\
5149 will be at an offset from the frame pointer.\n\
5150 @findex stack_pointer_rtx\n\
5151 @findex frame_pointer_rtx\n\
5152 @findex arg_pointer_rtx\n\
5153 The variables @code{stack_pointer_rtx}, @code{frame_pointer_rtx}, and\n\
5154 @code{arg_pointer_rtx} will have been initialized and should be used\n\
5155 to refer to those items.",
5156 rtx, (const_tree fndecl_or_type, bool incoming_p),
5157 default_static_chain)
5159 /* Fill in the trampoline at MEM with a call to FNDECL and a
5160 static chain value of CHAIN. */
5163 "This hook is called to initialize a trampoline.\n\
5164 @var{m_tramp} is an RTX for the memory block for the trampoline; @var{fndecl}\n\
5165 is the @code{FUNCTION_DECL} for the nested function; @var{static_chain} is an\n\
5166 RTX for the static chain value that should be passed to the function\n\
5167 when it is called.\n\
5169 If the target defines @code{TARGET_ASM_TRAMPOLINE_TEMPLATE}, then the\n\
5170 first thing this hook should do is emit a block move into @var{m_tramp}\n\
5171 from the memory block returned by @code{assemble_trampoline_template}.\n\
5172 Note that the block move need only cover the constant parts of the\n\
5173 trampoline. If the target isolates the variable parts of the trampoline\n\
5174 to the end, not all @code{TRAMPOLINE_SIZE} bytes need be copied.\n\
5176 If the target requires any other actions, such as flushing caches\n\
5177 (possibly calling function maybe_emit_call_builtin___clear_cache) or\n\
5178 enabling stack execution, these actions should be performed after\n\
5179 initializing the trampoline proper.",
5180 void, (rtx m_tramp, tree fndecl, rtx static_chain),
5181 default_trampoline_init)
5183 /* Emit a call to a function to clear the instruction cache. */
5185 (emit_call_builtin___clear_cache,
5186 "On targets that do not define a @code{clear_cache} insn expander,\n\
5187 but that define the @code{CLEAR_CACHE_INSN} macro,\n\
5188 maybe_emit_call_builtin___clear_cache relies on this target hook\n\
5189 to clear an address range in the instruction cache.\n\
5191 The default implementation calls the @code{__clear_cache} builtin,\n\
5192 taking the assembler name from the builtin declaration. Overriding\n\
5193 definitions may call alternate functions, with alternate calling\n\
5194 conventions, or emit alternate RTX to perform the job.",
5195 void, (rtx begin, rtx end),
5196 default_emit_call_builtin___clear_cache)
5198 /* Adjust the address of the trampoline in a target-specific way. */
5200 (trampoline_adjust_address,
5201 "This hook should perform any machine-specific adjustment in\n\
5202 the address of the trampoline. Its argument contains the address of the\n\
5203 memory block that was passed to @code{TARGET_TRAMPOLINE_INIT}. In case\n\
5204 the address to be used for a function call should be different from the\n\
5205 address at which the template was stored, the different address should\n\
5206 be returned; otherwise @var{addr} should be returned unchanged.\n\
5207 If this hook is not defined, @var{addr} will be used for function calls.",
5208 rtx, (rtx addr), NULL)
5211 (custom_function_descriptors,
5212 "If the target can use GCC's generic descriptor mechanism for nested\n\
5213 functions, define this hook to a power of 2 representing an unused bit\n\
5214 in function pointers which can be used to differentiate descriptors at\n\
5215 run time. This value gives the number of bytes by which descriptor\n\
5216 pointers are misaligned compared to function pointers. For example, on\n\
5217 targets that require functions to be aligned to a 4-byte boundary, a\n\
5218 value of either 1 or 2 is appropriate unless the architecture already\n\
5219 reserves the bit for another purpose, such as on ARM.\n\
5221 Define this hook to 0 if the target implements ABI support for\n\
5222 function descriptors in its standard calling sequence, like for example\n\
5225 Using descriptors for nested functions\n\
5226 eliminates the need for trampolines that reside on the stack and require\n\
5227 it to be made executable.",\
5230 /* Return the number of bytes of its own arguments that a function
5231 pops on returning, or 0 if the function pops no arguments and the
5232 caller must therefore pop them all after the function returns. */
5233 /* ??? tm.texi has no types for the parameters. */
5236 "This target hook returns the number of bytes of its own arguments that\n\
5237 a function pops on returning, or 0 if the function pops no arguments\n\
5238 and the caller must therefore pop them all after the function returns.\n\
5240 @var{fundecl} is a C variable whose value is a tree node that describes\n\
5241 the function in question. Normally it is a node of type\n\
5242 @code{FUNCTION_DECL} that describes the declaration of the function.\n\
5243 From this you can obtain the @code{DECL_ATTRIBUTES} of the function.\n\
5245 @var{funtype} is a C variable whose value is a tree node that\n\
5246 describes the function in question. Normally it is a node of type\n\
5247 @code{FUNCTION_TYPE} that describes the data type of the function.\n\
5248 From this it is possible to obtain the data types of the value and\n\
5249 arguments (if known).\n\
5251 When a call to a library function is being considered, @var{fundecl}\n\
5252 will contain an identifier node for the library function. Thus, if\n\
5253 you need to distinguish among various library functions, you can do so\n\
5254 by their names. Note that ``library function'' in this context means\n\
5255 a function used to perform arithmetic, whose name is known specially\n\
5256 in the compiler and was not mentioned in the C code being compiled.\n\
5258 @var{size} is the number of bytes of arguments passed on the\n\
5259 stack. If a variable number of bytes is passed, it is zero, and\n\
5260 argument popping will always be the responsibility of the calling function.\n\
5262 On the VAX, all functions always pop their arguments, so the definition\n\
5263 of this macro is @var{size}. On the 68000, using the standard\n\
5264 calling convention, no functions pop their arguments, so the value of\n\
5265 the macro is always 0 in this case. But an alternative calling\n\
5266 convention is available in which functions that take a fixed number of\n\
5267 arguments pop them but other functions (such as @code{printf}) pop\n\
5268 nothing (the caller pops all). When this convention is in use,\n\
5269 @var{funtype} is examined to determine whether a function takes a fixed\n\
5270 number of arguments.",
5271 poly_int64, (tree fundecl, tree funtype, poly_int64 size),
5272 default_return_pops_args)
5274 /* Return a mode wide enough to copy any function value that might be
5277 (get_raw_result_mode,
5278 "This target hook returns the mode to be used when accessing raw return\
5279 registers in @code{__builtin_return}. Define this macro if the value\
5280 in @var{reg_raw_mode} is not correct.",
5281 fixed_size_mode, (int regno),
5282 default_get_reg_raw_mode)
5284 /* Return a mode wide enough to copy any argument value that might be
5288 "This target hook returns the mode to be used when accessing raw argument\
5289 registers in @code{__builtin_apply_args}. Define this macro if the value\
5290 in @var{reg_raw_mode} is not correct.",
5291 fixed_size_mode, (int regno),
5292 default_get_reg_raw_mode)
5294 /* Return true if a type is an empty record. */
5297 "This target hook returns true if the type is an empty record. The default\n\
5298 is to return @code{false}.",
5299 bool, (const_tree type),
5300 hook_bool_const_tree_false)
5302 /* Warn about the change in empty class parameter passing ABI. */
5304 (warn_parameter_passing_abi,
5305 "This target hook warns about the change in empty class parameter passing\n\
5307 void, (cumulative_args_t ca, tree type),
5308 hook_void_CUMULATIVE_ARGS_tree)
5310 HOOK_VECTOR_END (calls)
5313 (use_pseudo_pic_reg,
5314 "This hook should return 1 in case pseudo register should be created\n\
5315 for pic_offset_table_rtx during function expand.",
5317 hook_bool_void_false)
5321 "Perform a target dependent initialization of pic_offset_table_rtx.\n\
5322 This hook is called at the start of register allocation.",
5326 /* Return the diagnostic message string if conversion from FROMTYPE
5327 to TOTYPE is not allowed, NULL otherwise. */
5329 (invalid_conversion,
5330 "If defined, this macro returns the diagnostic message when it is\n\
5331 invalid to convert from @var{fromtype} to @var{totype}, or @code{NULL}\n\
5332 if validity should be determined by the front end.",
5333 const char *, (const_tree fromtype, const_tree totype),
5334 hook_constcharptr_const_tree_const_tree_null)
5336 /* Return the diagnostic message string if the unary operation OP is
5337 not permitted on TYPE, NULL otherwise. */
5340 "If defined, this macro returns the diagnostic message when it is\n\
5341 invalid to apply operation @var{op} (where unary plus is denoted by\n\
5342 @code{CONVERT_EXPR}) to an operand of type @var{type}, or @code{NULL}\n\
5343 if validity should be determined by the front end.",
5344 const char *, (int op, const_tree type),
5345 hook_constcharptr_int_const_tree_null)
5347 /* Return the diagnostic message string if the binary operation OP
5348 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
5351 "If defined, this macro returns the diagnostic message when it is\n\
5352 invalid to apply operation @var{op} to operands of types @var{type1}\n\
5353 and @var{type2}, or @code{NULL} if validity should be determined by\n\
5355 const char *, (int op, const_tree type1, const_tree type2),
5356 hook_constcharptr_int_const_tree_const_tree_null)
5358 /* If values of TYPE are promoted to some other type when used in
5359 expressions (analogous to the integer promotions), return that type,
5360 or NULL_TREE otherwise. */
5363 "If defined, this target hook returns the type to which values of\n\
5364 @var{type} should be promoted when they appear in expressions,\n\
5365 analogous to the integer promotions, or @code{NULL_TREE} to use the\n\
5366 front end's normal promotion rules. This hook is useful when there are\n\
5367 target-specific types with special promotion rules.\n\
5368 This is currently used only by the C and C++ front ends.",
5369 tree, (const_tree type),
5370 hook_tree_const_tree_null)
5372 /* Convert EXPR to TYPE, if target-specific types with special conversion
5373 rules are involved. Return the converted expression, or NULL to apply
5374 the standard conversion rules. */
5377 "If defined, this hook returns the result of converting @var{expr} to\n\
5378 @var{type}. It should return the converted expression,\n\
5379 or @code{NULL_TREE} to apply the front end's normal conversion rules.\n\
5380 This hook is useful when there are target-specific types with special\n\
5381 conversion rules.\n\
5382 This is currently used only by the C and C++ front ends.",
5383 tree, (tree type, tree expr),
5384 hook_tree_tree_tree_null)
5387 (verify_type_context,
5388 "If defined, this hook returns false if there is a target-specific reason\n\
5389 why type @var{type} cannot be used in the source language context described\n\
5390 by @var{context}. When @var{silent_p} is false, the hook also reports an\n\
5391 error against @var{loc} for invalid uses of @var{type}.\n\
5393 Calls to this hook should be made through the global function\n\
5394 @code{verify_type_context}, which makes the @var{silent_p} parameter\n\
5395 default to false and also handles @code{error_mark_node}.\n\
5397 The default implementation always returns true.",
5398 bool, (location_t loc, type_context_kind context, const_tree type,
5403 (can_change_mode_class,
5404 "This hook returns true if it is possible to bitcast values held in\n\
5405 registers of class @var{rclass} from mode @var{from} to mode @var{to}\n\
5406 and if doing so preserves the low-order bits that are common to both modes.\n\
5407 The result is only meaningful if @var{rclass} has registers that can hold\n\
5408 both @code{from} and @code{to}. The default implementation returns true.\n\
5410 As an example of when such bitcasting is invalid, loading 32-bit integer or\n\
5411 floating-point objects into floating-point registers on Alpha extends them\n\
5412 to 64 bits. Therefore loading a 64-bit object and then storing it as a\n\
5413 32-bit object does not store the low-order 32 bits, as would be the case\n\
5414 for a normal register. Therefore, @file{alpha.h} defines\n\
5415 @code{TARGET_CAN_CHANGE_MODE_CLASS} to return:\n\
5418 (GET_MODE_SIZE (from) == GET_MODE_SIZE (to)\n\
5419 || !reg_classes_intersect_p (FLOAT_REGS, rclass))\n\
5420 @end smallexample\n\
5422 Even if storing from a register in mode @var{to} would be valid,\n\
5423 if both @var{from} and @code{raw_reg_mode} for @var{rclass} are wider\n\
5424 than @code{word_mode}, then we must prevent @var{to} narrowing the\n\
5425 mode. This happens when the middle-end assumes that it can load\n\
5426 or store pieces of an @var{N}-word pseudo, and that the pseudo will\n\
5427 eventually be allocated to @var{N} @code{word_mode} hard registers.\n\
5428 Failure to prevent this kind of mode change will result in the\n\
5429 entire @code{raw_reg_mode} being modified instead of the partial\n\
5430 value that the middle-end intended.",
5431 bool, (machine_mode from, machine_mode to, reg_class_t rclass),
5432 hook_bool_mode_mode_reg_class_t_true)
5434 /* Change pseudo allocno class calculated by IRA. */
5436 (ira_change_pseudo_allocno_class,
5437 "A target hook which can change allocno class for given pseudo from\n\
5438 allocno and best class calculated by IRA.\n\
5440 The default version of this target hook always returns given class.",
5441 reg_class_t, (int, reg_class_t, reg_class_t),
5442 default_ira_change_pseudo_allocno_class)
5444 /* Return true if we use LRA instead of reload. */
5447 "A target hook which returns true if we use LRA instead of reload pass.\
5449 The default version of this target hook returns true. New ports\
5450 should use LRA, and existing ports are encouraged to convert.",
5454 /* Return register priority of given hard regno for the current target. */
5457 "A target hook which returns the register priority number to which the\
5458 register @var{hard_regno} belongs to. The bigger the number, the\
5459 more preferable the hard register usage (when all other conditions are\
5460 the same). This hook can be used to prefer some hard register over\
5461 others in LRA. For example, some x86-64 register usage needs\
5462 additional prefix which makes instructions longer. The hook can\
5463 return lower priority number for such registers make them less favorable\
5464 and as result making the generated code smaller.\
5466 The default version of this target hook returns always zero.",
5468 default_register_priority)
5470 /* Return true if we need register usage leveling. */
5472 (register_usage_leveling_p,
5473 "A target hook which returns true if we need register usage leveling.\
5474 That means if a few hard registers are equally good for the\
5475 assignment, we choose the least used hard register. The register\
5476 usage leveling may be profitable for some targets. Don't use the\
5477 usage leveling for targets with conditional execution or targets\
5478 with big register files as it hurts if-conversion and cross-jumping\
5481 The default version of this target hook returns always false.",
5483 default_register_usage_leveling_p)
5485 /* Return true if maximal address displacement can be different. */
5487 (different_addr_displacement_p,
5488 "A target hook which returns true if an address with the same structure\
5489 can have different maximal legitimate displacement. For example, the\
5490 displacement can depend on memory mode or on operand combinations in\
5493 The default version of this target hook returns always false.",
5495 default_different_addr_displacement_p)
5497 /* Determine class for spilling pseudos of given mode into registers
5498 instead of memory. */
5501 "This hook defines a class of registers which could be used for spilling\
5502 pseudos of the given mode and class, or @code{NO_REGS} if only memory\
5503 should be used. Not defining this hook is equivalent to returning\
5504 @code{NO_REGS} for all inputs.",
5505 reg_class_t, (reg_class_t, machine_mode),
5508 /* Determine an additional allocno class. */
5510 (additional_allocno_class_p,
5511 "This hook should return @code{true} if given class of registers should\
5512 be an allocno class in any way. Usually RA uses only one register\
5513 class from all classes containing the same register set. In some\
5514 complicated cases, you need to have two or more such classes as\
5515 allocno ones for RA correct work. Not defining this hook is\
5516 equivalent to returning @code{false} for all inputs.",
5517 bool, (reg_class_t),
5518 hook_bool_reg_class_t_false)
5522 "This hook defines the machine mode to use for the boolean result of\
5523 conditional store patterns. The ICODE argument is the instruction code\
5524 for the cstore being performed. Not definiting this hook is the same\
5525 as accepting the mode encoded into operand 0 of the cstore expander\
5527 scalar_int_mode, (enum insn_code icode),
5528 default_cstore_mode)
5530 /* This target hook allows the backend to compute the register pressure
5533 (compute_pressure_classes,
5534 "A target hook which lets a backend compute the set of pressure classes to\
5535 be used by those optimization passes which take register pressure into\
5536 account, as opposed to letting IRA compute them. It returns the number of\
5537 register classes stored in the array @var{pressure_classes}.",
5538 int, (enum reg_class *pressure_classes), NULL)
5540 /* True if a structure, union or array with MODE containing FIELD should
5541 be accessed using BLKmode. */
5543 (member_type_forces_blk,
5544 "Return true if a structure, union or array containing @var{field} should\n\
5545 be accessed using @code{BLKMODE}.\n\
5547 If @var{field} is the only field in the structure, @var{mode} is its\n\
5548 mode, otherwise @var{mode} is VOIDmode. @var{mode} is provided in the\n\
5549 case where structures of one field would require the structure's mode to\n\
5550 retain the field's mode.\n\
5552 Normally, this is not needed.",
5553 bool, (const_tree field, machine_mode mode),
5554 default_member_type_forces_blk)
5556 /* See tree-ssa-math-opts.c:divmod_candidate_p for conditions
5557 that gate the divod transform. */
5559 (expand_divmod_libfunc,
5560 "Define this hook for enabling divmod transform if the port does not have\n\
5561 hardware divmod insn but defines target-specific divmod libfuncs.",
5562 void, (rtx libfunc, machine_mode mode, rtx op0, rtx op1, rtx *quot, rtx *rem),
5565 /* Return the class for a secondary reload, and fill in extra information. */
5568 "Many machines have some registers that cannot be copied directly to or\n\
5569 from memory or even from other types of registers. An example is the\n\
5570 @samp{MQ} register, which on most machines, can only be copied to or\n\
5571 from general registers, but not memory. Below, we shall be using the\n\
5572 term 'intermediate register' when a move operation cannot be performed\n\
5573 directly, but has to be done by copying the source into the intermediate\n\
5574 register first, and then copying the intermediate register to the\n\
5575 destination. An intermediate register always has the same mode as\n\
5576 source and destination. Since it holds the actual value being copied,\n\
5577 reload might apply optimizations to re-use an intermediate register\n\
5578 and eliding the copy from the source when it can determine that the\n\
5579 intermediate register still holds the required value.\n\
5581 Another kind of secondary reload is required on some machines which\n\
5582 allow copying all registers to and from memory, but require a scratch\n\
5583 register for stores to some memory locations (e.g., those with symbolic\n\
5584 address on the RT, and those with certain symbolic address on the SPARC\n\
5585 when compiling PIC)@. Scratch registers need not have the same mode\n\
5586 as the value being copied, and usually hold a different value than\n\
5587 that being copied. Special patterns in the md file are needed to\n\
5588 describe how the copy is performed with the help of the scratch register;\n\
5589 these patterns also describe the number, register class(es) and mode(s)\n\
5590 of the scratch register(s).\n\
5592 In some cases, both an intermediate and a scratch register are required.\n\
5594 For input reloads, this target hook is called with nonzero @var{in_p},\n\
5595 and @var{x} is an rtx that needs to be copied to a register of class\n\
5596 @var{reload_class} in @var{reload_mode}. For output reloads, this target\n\
5597 hook is called with zero @var{in_p}, and a register of class @var{reload_class}\n\
5598 needs to be copied to rtx @var{x} in @var{reload_mode}.\n\
5600 If copying a register of @var{reload_class} from/to @var{x} requires\n\
5601 an intermediate register, the hook @code{secondary_reload} should\n\
5602 return the register class required for this intermediate register.\n\
5603 If no intermediate register is required, it should return NO_REGS.\n\
5604 If more than one intermediate register is required, describe the one\n\
5605 that is closest in the copy chain to the reload register.\n\
5607 If scratch registers are needed, you also have to describe how to\n\
5608 perform the copy from/to the reload register to/from this\n\
5609 closest intermediate register. Or if no intermediate register is\n\
5610 required, but still a scratch register is needed, describe the\n\
5611 copy from/to the reload register to/from the reload operand @var{x}.\n\
5613 You do this by setting @code{sri->icode} to the instruction code of a pattern\n\
5614 in the md file which performs the move. Operands 0 and 1 are the output\n\
5615 and input of this copy, respectively. Operands from operand 2 onward are\n\
5616 for scratch operands. These scratch operands must have a mode, and a\n\
5617 single-register-class\n\
5618 @c [later: or memory]\n\
5619 output constraint.\n\
5621 When an intermediate register is used, the @code{secondary_reload}\n\
5622 hook will be called again to determine how to copy the intermediate\n\
5623 register to/from the reload operand @var{x}, so your hook must also\n\
5624 have code to handle the register class of the intermediate operand.\n\
5626 @c [For later: maybe we'll allow multi-alternative reload patterns -\n\
5627 @c the port maintainer could name a mov<mode> pattern that has clobbers -\n\
5628 @c and match the constraints of input and output to determine the required\n\
5629 @c alternative. A restriction would be that constraints used to match\n\
5630 @c against reloads registers would have to be written as register class\n\
5631 @c constraints, or we need a new target macro / hook that tells us if an\n\
5632 @c arbitrary constraint can match an unknown register of a given class.\n\
5633 @c Such a macro / hook would also be useful in other places.]\n\
5636 @var{x} might be a pseudo-register or a @code{subreg} of a\n\
5637 pseudo-register, which could either be in a hard register or in memory.\n\
5638 Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is\n\
5639 in memory and the hard register number if it is in a register.\n\
5641 Scratch operands in memory (constraint @code{\"=m\"} / @code{\"=&m\"}) are\n\
5642 currently not supported. For the time being, you will have to continue\n\
5643 to use @code{TARGET_SECONDARY_MEMORY_NEEDED} for that purpose.\n\
5645 @code{copy_cost} also uses this target hook to find out how values are\n\
5646 copied. If you want it to include some extra cost for the need to allocate\n\
5647 (a) scratch register(s), set @code{sri->extra_cost} to the additional cost.\n\
5648 Or if two dependent moves are supposed to have a lower cost than the sum\n\
5649 of the individual moves due to expected fortuitous scheduling and/or special\n\
5650 forwarding logic, you can set @code{sri->extra_cost} to a negative amount.",
5652 (bool in_p, rtx x, reg_class_t reload_class, machine_mode reload_mode,
5653 secondary_reload_info *sri),
5654 default_secondary_reload)
5657 (secondary_memory_needed,
5658 "Certain machines have the property that some registers cannot be copied\n\
5659 to some other registers without using memory. Define this hook on\n\
5660 those machines to return true if objects of mode @var{m} in registers\n\
5661 of @var{class1} can only be copied to registers of class @var{class2} by\n\
5662 storing a register of @var{class1} into memory and loading that memory\n\
5663 location into a register of @var{class2}. The default definition returns\n\
5664 false for all inputs.",
5665 bool, (machine_mode mode, reg_class_t class1, reg_class_t class2),
5666 hook_bool_mode_reg_class_t_reg_class_t_false)
5669 (secondary_memory_needed_mode,
5670 "If @code{TARGET_SECONDARY_MEMORY_NEEDED} tells the compiler to use memory\n\
5671 when moving between two particular registers of mode @var{mode},\n\
5672 this hook specifies the mode that the memory should have.\n\
5674 The default depends on @code{TARGET_LRA_P}. Without LRA, the default\n\
5675 is to use a word-sized mode for integral modes that are smaller than a\n\
5676 a word. This is right thing to do on most machines because it ensures\n\
5677 that all bits of the register are copied and prevents accesses to the\n\
5678 registers in a narrower mode, which some machines prohibit for\n\
5679 floating-point registers.\n\
5681 However, this default behavior is not correct on some machines, such as\n\
5682 the DEC Alpha, that store short integers in floating-point registers\n\
5683 differently than in integer registers. On those machines, the default\n\
5684 widening will not work correctly and you must define this hook to\n\
5685 suppress that widening in some cases. See the file @file{alpha.c} for\n\
5688 With LRA, the default is to use @var{mode} unmodified.",
5689 machine_mode, (machine_mode mode),
5690 default_secondary_memory_needed_mode)
5692 /* Given an rtx X being reloaded into a reg required to be in class CLASS,
5693 return the class of reg to actually use. */
5695 (preferred_reload_class,
5696 "A target hook that places additional restrictions on the register class\n\
5697 to use when it is necessary to copy value @var{x} into a register in class\n\
5698 @var{rclass}. The value is a register class; perhaps @var{rclass}, or perhaps\n\
5699 another, smaller class.\n\
5701 The default version of this hook always returns value of @code{rclass} argument.\n\
5703 Sometimes returning a more restrictive class makes better code. For\n\
5704 example, on the 68000, when @var{x} is an integer constant that is in range\n\
5705 for a @samp{moveq} instruction, the value of this macro is always\n\
5706 @code{DATA_REGS} as long as @var{rclass} includes the data registers.\n\
5707 Requiring a data register guarantees that a @samp{moveq} will be used.\n\
5709 One case where @code{TARGET_PREFERRED_RELOAD_CLASS} must not return\n\
5710 @var{rclass} is if @var{x} is a legitimate constant which cannot be\n\
5711 loaded into some register class. By returning @code{NO_REGS} you can\n\
5712 force @var{x} into a memory location. For example, rs6000 can load\n\
5713 immediate values into general-purpose registers, but does not have an\n\
5714 instruction for loading an immediate value into a floating-point\n\
5715 register, so @code{TARGET_PREFERRED_RELOAD_CLASS} returns @code{NO_REGS} when\n\
5716 @var{x} is a floating-point constant. If the constant can't be loaded\n\
5717 into any kind of register, code generation will be better if\n\
5718 @code{TARGET_LEGITIMATE_CONSTANT_P} makes the constant illegitimate instead\n\
5719 of using @code{TARGET_PREFERRED_RELOAD_CLASS}.\n\
5721 If an insn has pseudos in it after register allocation, reload will go\n\
5722 through the alternatives and call repeatedly @code{TARGET_PREFERRED_RELOAD_CLASS}\n\
5723 to find the best one. Returning @code{NO_REGS}, in this case, makes\n\
5724 reload add a @code{!} in front of the constraint: the x86 back-end uses\n\
5725 this feature to discourage usage of 387 registers when math is done in\n\
5726 the SSE registers (and vice versa).",
5728 (rtx x, reg_class_t rclass),
5729 default_preferred_reload_class)
5731 /* Like TARGET_PREFERRED_RELOAD_CLASS, but for output reloads instead of
5734 (preferred_output_reload_class,
5735 "Like @code{TARGET_PREFERRED_RELOAD_CLASS}, but for output reloads instead of\n\
5738 The default version of this hook always returns value of @code{rclass}\n\
5741 You can also use @code{TARGET_PREFERRED_OUTPUT_RELOAD_CLASS} to discourage\n\
5742 reload from using some alternatives, like @code{TARGET_PREFERRED_RELOAD_CLASS}.",
5744 (rtx x, reg_class_t rclass),
5745 default_preferred_output_reload_class)
5748 (select_early_remat_modes,
5749 "On some targets, certain modes cannot be held in registers around a\n\
5750 standard ABI call and are relatively expensive to spill to the stack.\n\
5751 The early rematerialization pass can help in such cases by aggressively\n\
5752 recomputing values after calls, so that they don't need to be spilled.\n\
5754 This hook returns the set of such modes by setting the associated bits\n\
5755 in @var{modes}. The default implementation selects no modes, which has\n\
5756 the effect of disabling the early rematerialization pass.",
5757 void, (sbitmap modes),
5758 default_select_early_remat_modes)
5761 (class_likely_spilled_p,
5762 "A target hook which returns @code{true} if pseudos that have been assigned\n\
5763 to registers of class @var{rclass} would likely be spilled because\n\
5764 registers of @var{rclass} are needed for spill registers.\n\
5766 The default version of this target hook returns @code{true} if @var{rclass}\n\
5767 has exactly one register and @code{false} otherwise. On most machines, this\n\
5768 default should be used. For generally register-starved machines, such as\n\
5769 i386, or machines with right register constraints, such as SH, this hook\n\
5770 can be used to avoid excessive spilling.\n\
5772 This hook is also used by some of the global intra-procedural code\n\
5773 transformations to throtle code motion, to avoid increasing register\n\
5775 bool, (reg_class_t rclass),
5776 default_class_likely_spilled_p)
5778 /* Return the maximum number of consecutive registers
5779 needed to represent mode MODE in a register of class RCLASS. */
5782 "A target hook returns the maximum number of consecutive registers\n\
5783 of class @var{rclass} needed to hold a value of mode @var{mode}.\n\
5785 This is closely related to the macro @code{TARGET_HARD_REGNO_NREGS}.\n\
5786 In fact, the value returned by @code{TARGET_CLASS_MAX_NREGS (@var{rclass},\n\
5787 @var{mode})} target hook should be the maximum value of\n\
5788 @code{TARGET_HARD_REGNO_NREGS (@var{regno}, @var{mode})} for all @var{regno}\n\
5789 values in the class @var{rclass}.\n\
5791 This target hook helps control the handling of multiple-word values\n\
5792 in the reload pass.\n\
5794 The default version of this target hook returns the size of @var{mode}\n\
5796 unsigned char, (reg_class_t rclass, machine_mode mode),
5797 default_class_max_nregs)
5800 (preferred_rename_class,
5801 "A target hook that places additional preference on the register\
5802 class to use when it is necessary to rename a register in class\
5803 @var{rclass} to another class, or perhaps @var{NO_REGS}, if no\
5804 preferred register class is found or hook @code{preferred_rename_class}\
5805 is not implemented.\
5806 Sometimes returning a more restrictive class makes better code. For\
5807 example, on ARM, thumb-2 instructions using @code{LO_REGS} may be\
5808 smaller than instructions using @code{GENERIC_REGS}. By returning\
5809 @code{LO_REGS} from @code{preferred_rename_class}, code size can\
5811 reg_class_t, (reg_class_t rclass),
5812 default_preferred_rename_class)
5814 /* This target hook allows the backend to avoid unsafe substitution
5815 during register allocation. */
5817 (cannot_substitute_mem_equiv_p,
5818 "A target hook which returns @code{true} if @var{subst} can't\n\
5819 substitute safely pseudos with equivalent memory values during\n\
5820 register allocation.\n\
5821 The default version of this target hook returns @code{false}.\n\
5822 On most machines, this default should be used. For generally\n\
5823 machines with non orthogonal register usage for addressing, such\n\
5824 as SH, this hook can be used to avoid excessive spilling.",
5826 hook_bool_rtx_false)
5828 /* This target hook allows the backend to legitimize base plus
5829 displacement addressing. */
5831 (legitimize_address_displacement,
5832 "This hook tries to split address offset @var{orig_offset} into\n\
5833 two parts: one that should be added to the base address to create\n\
5834 a local anchor point, and an additional offset that can be applied\n\
5835 to the anchor to address a value of mode @var{mode}. The idea is that\n\
5836 the local anchor could be shared by other accesses to nearby locations.\n\
5838 The hook returns true if it succeeds, storing the offset of the\n\
5839 anchor from the base in @var{offset1} and the offset of the final address\n\
5840 from the anchor in @var{offset2}. The default implementation returns false.",
5841 bool, (rtx *offset1, rtx *offset2, poly_int64 orig_offset, machine_mode mode),
5842 default_legitimize_address_displacement)
5844 /* This target hook allows the backend to perform additional
5845 processing while initializing for variable expansion. */
5847 (expand_to_rtl_hook,
5848 "This hook is called just before expansion into rtl, allowing the target\n\
5849 to perform additional initializations or analysis before the expansion.\n\
5850 For example, the rs6000 port uses it to allocate a scratch stack slot\n\
5851 for use in copying SDmode values between memory and floating point\n\
5852 registers whenever the function being expanded has any SDmode\n\
5857 /* This target hook allows the backend to perform additional
5858 instantiations on rtx that are not actually in insns yet,
5859 but will be later. */
5862 "This hook allows the backend to perform additional instantiations on rtl\n\
5863 that are not actually in any insns yet, but will be later.",
5869 "This hook returns the number of consecutive hard registers, starting\n\
5870 at register number @var{regno}, required to hold a value of mode\n\
5871 @var{mode}. This hook must never return zero, even if a register\n\
5872 cannot hold the requested mode - indicate that with\n\
5873 @code{TARGET_HARD_REGNO_MODE_OK} and/or\n\
5874 @code{TARGET_CAN_CHANGE_MODE_CLASS} instead.\n\
5876 The default definition returns the number of words in @var{mode}.",
5877 unsigned int, (unsigned int regno, machine_mode mode),
5878 default_hard_regno_nregs)
5881 (hard_regno_mode_ok,
5882 "This hook returns true if it is permissible to store a value\n\
5883 of mode @var{mode} in hard register number @var{regno} (or in several\n\
5884 registers starting with that one). The default definition returns true\n\
5887 You need not include code to check for the numbers of fixed registers,\n\
5888 because the allocation mechanism considers them to be always occupied.\n\
5890 @cindex register pairs\n\
5891 On some machines, double-precision values must be kept in even/odd\n\
5892 register pairs. You can implement that by defining this hook to reject\n\
5893 odd register numbers for such modes.\n\
5895 The minimum requirement for a mode to be OK in a register is that the\n\
5896 @samp{mov@var{mode}} instruction pattern support moves between the\n\
5897 register and other hard register in the same class and that moving a\n\
5898 value into the register and back out not alter it.\n\
5900 Since the same instruction used to move @code{word_mode} will work for\n\
5901 all narrower integer modes, it is not necessary on any machine for\n\
5902 this hook to distinguish between these modes, provided you define\n\
5903 patterns @samp{movhi}, etc., to take advantage of this. This is\n\
5904 useful because of the interaction between @code{TARGET_HARD_REGNO_MODE_OK}\n\
5905 and @code{TARGET_MODES_TIEABLE_P}; it is very desirable for all integer\n\
5906 modes to be tieable.\n\
5908 Many machines have special registers for floating point arithmetic.\n\
5909 Often people assume that floating point machine modes are allowed only\n\
5910 in floating point registers. This is not true. Any registers that\n\
5911 can hold integers can safely @emph{hold} a floating point machine\n\
5912 mode, whether or not floating arithmetic can be done on it in those\n\
5913 registers. Integer move instructions can be used to move the values.\n\
5915 On some machines, though, the converse is true: fixed-point machine\n\
5916 modes may not go in floating registers. This is true if the floating\n\
5917 registers normalize any value stored in them, because storing a\n\
5918 non-floating value there would garble it. In this case,\n\
5919 @code{TARGET_HARD_REGNO_MODE_OK} should reject fixed-point machine modes in\n\
5920 floating registers. But if the floating registers do not automatically\n\
5921 normalize, if you can store any bit pattern in one and retrieve it\n\
5922 unchanged without a trap, then any machine mode may go in a floating\n\
5923 register, so you can define this hook to say so.\n\
5925 The primary significance of special floating registers is rather that\n\
5926 they are the registers acceptable in floating point arithmetic\n\
5927 instructions. However, this is of no concern to\n\
5928 @code{TARGET_HARD_REGNO_MODE_OK}. You handle it by writing the proper\n\
5929 constraints for those instructions.\n\
5931 On some machines, the floating registers are especially slow to access,\n\
5932 so that it is better to store a value in a stack frame than in such a\n\
5933 register if floating point arithmetic is not being done. As long as the\n\
5934 floating registers are not in class @code{GENERAL_REGS}, they will not\n\
5935 be used unless some pattern's constraint asks for one.",
5936 bool, (unsigned int regno, machine_mode mode),
5937 hook_bool_uint_mode_true)
5941 "This hook returns true if a value of mode @var{mode1} is accessible\n\
5942 in mode @var{mode2} without copying.\n\
5944 If @code{TARGET_HARD_REGNO_MODE_OK (@var{r}, @var{mode1})} and\n\
5945 @code{TARGET_HARD_REGNO_MODE_OK (@var{r}, @var{mode2})} are always\n\
5946 the same for any @var{r}, then\n\
5947 @code{TARGET_MODES_TIEABLE_P (@var{mode1}, @var{mode2})}\n\
5948 should be true. If they differ for any @var{r}, you should define\n\
5949 this hook to return false unless some other mechanism ensures the\n\
5950 accessibility of the value in a narrower mode.\n\
5952 You should define this hook to return true in as many cases as\n\
5953 possible since doing so will allow GCC to perform better register\n\
5954 allocation. The default definition returns true unconditionally.",
5955 bool, (machine_mode mode1, machine_mode mode2),
5956 hook_bool_mode_mode_true)
5958 /* Return true if is OK to use a hard register REGNO as scratch register
5961 (hard_regno_scratch_ok,
5962 "This target hook should return @code{true} if it is OK to use a hard register\n\
5963 @var{regno} as scratch reg in peephole2.\n\
5965 One common use of this macro is to prevent using of a register that\n\
5966 is not saved by a prologue in an interrupt handler.\n\
5968 The default version of this hook always returns @code{true}.",
5969 bool, (unsigned int regno),
5970 default_hard_regno_scratch_ok)
5973 (hard_regno_call_part_clobbered,
5974 "ABIs usually specify that calls must preserve the full contents\n\
5975 of a particular register, or that calls can alter any part of a\n\
5976 particular register. This information is captured by the target macro\n\
5977 @code{CALL_REALLY_USED_REGISTERS}. However, some ABIs specify that calls\n\
5978 must preserve certain bits of a particular register but can alter others.\n\
5979 This hook should return true if this applies to at least one of the\n\
5980 registers in @samp{(reg:@var{mode} @var{regno})}, and if as a result the\n\
5981 call would alter part of the @var{mode} value. For example, if a call\n\
5982 preserves the low 32 bits of a 64-bit hard register @var{regno} but can\n\
5983 clobber the upper 32 bits, this hook should return true for a 64-bit mode\n\
5984 but false for a 32-bit mode.\n\
5986 The value of @var{abi_id} comes from the @code{predefined_function_abi}\n\
5987 structure that describes the ABI of the call; see the definition of the\n\
5988 structure for more details. If (as is usual) the target uses the same ABI\n\
5989 for all functions in a translation unit, @var{abi_id} is always 0.\n\
5991 The default implementation returns false, which is correct\n\
5992 for targets that don't have partly call-clobbered registers.",
5993 bool, (unsigned int abi_id, unsigned int regno, machine_mode mode),
5994 hook_bool_uint_uint_mode_false)
5997 (get_multilib_abi_name,
5998 "This hook returns name of multilib ABI name.",
5999 const char *, (void),
6000 hook_constcharptr_void_null)
6002 /* Return the smallest number of different values for which it is best to
6003 use a jump-table instead of a tree of conditional branches. */
6005 (case_values_threshold,
6006 "This function return the smallest number of different values for which it\n\
6007 is best to use a jump-table instead of a tree of conditional branches.\n\
6008 The default is four for machines with a @code{casesi} instruction and\n\
6009 five otherwise. This is best for most machines.",
6010 unsigned int, (void),
6011 default_case_values_threshold)
6014 (starting_frame_offset,
6015 "This hook returns the offset from the frame pointer to the first local\n\
6016 variable slot to be allocated. If @code{FRAME_GROWS_DOWNWARD}, it is the\n\
6017 offset to @emph{end} of the first slot allocated, otherwise it is the\n\
6018 offset to @emph{beginning} of the first slot allocated. The default\n\
6019 implementation returns 0.",
6020 HOST_WIDE_INT, (void),
6023 /* Optional callback to advise the target to compute the frame layout. */
6025 (compute_frame_layout,
6026 "This target hook is called once each time the frame layout needs to be\n\
6027 recalculated. The calculations can be cached by the target and can then\n\
6028 be used by @code{INITIAL_ELIMINATION_OFFSET} instead of re-computing the\n\
6029 layout on every invocation of that hook. This is particularly useful\n\
6030 for targets that have an expensive frame layout function. Implementing\n\
6031 this callback is optional.",
6035 /* Return true if a function must have and use a frame pointer. */
6037 (frame_pointer_required,
6038 "This target hook should return @code{true} if a function must have and use\n\
6039 a frame pointer. This target hook is called in the reload pass. If its return\n\
6040 value is @code{true} the function will have a frame pointer.\n\
6042 This target hook can in principle examine the current function and decide\n\
6043 according to the facts, but on most machines the constant @code{false} or the\n\
6044 constant @code{true} suffices. Use @code{false} when the machine allows code\n\
6045 to be generated with no frame pointer, and doing so saves some time or space.\n\
6046 Use @code{true} when there is no possible advantage to avoiding a frame\n\
6049 In certain cases, the compiler does not know how to produce valid code\n\
6050 without a frame pointer. The compiler recognizes those cases and\n\
6051 automatically gives the function a frame pointer regardless of what\n\
6052 @code{targetm.frame_pointer_required} returns. You don't need to worry about\n\
6055 In a function that does not require a frame pointer, the frame pointer\n\
6056 register can be allocated for ordinary usage, unless you mark it as a\n\
6057 fixed register. See @code{FIXED_REGISTERS} for more information.\n\
6059 Default return value is @code{false}.",
6061 hook_bool_void_false)
6063 /* Returns true if the compiler is allowed to try to replace register number
6064 from-reg with register number to-reg. */
6067 "This target hook should return @code{true} if the compiler is allowed to\n\
6068 try to replace register number @var{from_reg} with register number\n\
6069 @var{to_reg}. This target hook will usually be @code{true}, since most of the\n\
6070 cases preventing register elimination are things that the compiler already\n\
6073 Default return value is @code{true}.",
6074 bool, (const int from_reg, const int to_reg),
6075 hook_bool_const_int_const_int_true)
6077 /* Modify any or all of fixed_regs, call_used_regs, global_regs,
6078 reg_names, and reg_class_contents to account of the vagaries of the
6081 (conditional_register_usage,
6082 "This hook may conditionally modify five variables\n\
6083 @code{fixed_regs}, @code{call_used_regs}, @code{global_regs},\n\
6084 @code{reg_names}, and @code{reg_class_contents}, to take into account\n\
6085 any dependence of these register sets on target flags. The first three\n\
6086 of these are of type @code{char []} (interpreted as boolean vectors).\n\
6087 @code{global_regs} is a @code{const char *[]}, and\n\
6088 @code{reg_class_contents} is a @code{HARD_REG_SET}. Before the macro is\n\
6089 called, @code{fixed_regs}, @code{call_used_regs},\n\
6090 @code{reg_class_contents}, and @code{reg_names} have been initialized\n\
6091 from @code{FIXED_REGISTERS}, @code{CALL_USED_REGISTERS},\n\
6092 @code{REG_CLASS_CONTENTS}, and @code{REGISTER_NAMES}, respectively.\n\
6093 @code{global_regs} has been cleared, and any @option{-ffixed-@var{reg}},\n\
6094 @option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}\n\
6095 command options have been applied.\n\
6097 @cindex disabling certain registers\n\
6098 @cindex controlling register usage\n\
6099 If the usage of an entire class of registers depends on the target\n\
6100 flags, you may indicate this to GCC by using this macro to modify\n\
6101 @code{fixed_regs} and @code{call_used_regs} to 1 for each of the\n\
6102 registers in the classes which should not be used by GCC@. Also make\n\
6103 @code{define_register_constraint}s return @code{NO_REGS} for constraints\n\
6104 that shouldn't be used.\n\
6106 (However, if this class is not included in @code{GENERAL_REGS} and all\n\
6107 of the insn patterns whose constraints permit this class are\n\
6108 controlled by target switches, then GCC will automatically avoid using\n\
6109 these registers when the target switches are opposed to them.)",
6114 (stack_clash_protection_alloca_probe_range,
6115 "Some targets have an ABI defined interval for which no probing needs to be done.\n\
6116 When a probe does need to be done this same interval is used as the probe distance \
6117 up when doing stack clash protection for alloca.\n\
6118 On such targets this value can be set to override the default probing up interval.\n\
6119 Define this variable to return nonzero if such a probe range is required or zero otherwise. \
6120 Defining this hook also requires your functions which make use of alloca to have at least 8 byes\
6121 of outgoing arguments. If this is not the case the stack will be corrupted.\n\
6122 You need not define this macro if it would always have the value zero.",
6123 HOST_WIDE_INT, (void),
6124 default_stack_clash_protection_alloca_probe_range)
6127 /* Functions specific to the C family of frontends. */
6129 #define HOOK_PREFIX "TARGET_C_"
6130 HOOK_VECTOR (TARGET_C, c)
6132 /* ??? Documenting this hook requires a GFDL license grant. */
6135 "Return machine mode for non-standard constant literal suffix @var{c},\
6136 or VOIDmode if non-standard suffixes are unsupported.",
6137 machine_mode, (char c),
6138 default_mode_for_suffix)
6142 "Return a value, with the same meaning as the C99 macro\
6143 @code{FLT_EVAL_METHOD} that describes which excess precision should be\
6144 applied. @var{type} is either @code{EXCESS_PRECISION_TYPE_IMPLICIT},\
6145 @code{EXCESS_PRECISION_TYPE_FAST}, or\
6146 @code{EXCESS_PRECISION_TYPE_STANDARD}. For\
6147 @code{EXCESS_PRECISION_TYPE_IMPLICIT}, the target should return which\
6148 precision and range operations will be implictly evaluated in regardless\
6149 of the excess precision explicitly added. For\
6150 @code{EXCESS_PRECISION_TYPE_STANDARD} and\
6151 @code{EXCESS_PRECISION_TYPE_FAST}, the target should return the\
6152 explicit excess precision that should be added depending on the\
6153 value set for @option{-fexcess-precision=@r{[}standard@r{|}fast@r{]}}.\
6154 Note that unpredictable explicit excess precision does not make sense,\
6155 so a target should never return @code{FLT_EVAL_METHOD_UNPREDICTABLE}\
6156 when @var{type} is @code{EXCESS_PRECISION_TYPE_STANDARD} or\
6157 @code{EXCESS_PRECISION_TYPE_FAST}.",
6158 enum flt_eval_method, (enum excess_precision_type type),
6159 default_excess_precision)
6163 /* Functions specific to the C++ frontend. */
6165 #define HOOK_PREFIX "TARGET_CXX_"
6166 HOOK_VECTOR (TARGET_CXX, cxx)
6168 /* Return the integer type used for guard variables. */
6171 "Define this hook to override the integer type used for guard variables.\n\
6172 These are used to implement one-time construction of static objects. The\n\
6173 default is long_long_integer_type_node.",
6175 default_cxx_guard_type)
6177 /* Return true if only the low bit of the guard should be tested. */
6180 "This hook determines how guard variables are used. It should return\n\
6181 @code{false} (the default) if the first byte should be used. A return value of\n\
6182 @code{true} indicates that only the least significant bit should be used.",
6184 hook_bool_void_false)
6186 /* Returns the size of the array cookie for an array of type. */
6189 "This hook returns the size of the cookie to use when allocating an array\n\
6190 whose elements have the indicated @var{type}. Assumes that it is already\n\
6191 known that a cookie is needed. The default is\n\
6192 @code{max(sizeof (size_t), alignof(type))}, as defined in section 2.7 of the\n\
6193 IA64/Generic C++ ABI@.",
6195 default_cxx_get_cookie_size)
6197 /* Returns true if the element size should be stored in the array cookie. */
6200 "This hook should return @code{true} if the element size should be stored in\n\
6201 array cookies. The default is to return @code{false}.",
6203 hook_bool_void_false)
6205 /* Allows backends to perform additional processing when
6206 deciding if a class should be exported or imported. */
6208 (import_export_class,
6209 "If defined by a backend this hook allows the decision made to export\n\
6210 class @var{type} to be overruled. Upon entry @var{import_export}\n\
6211 will contain 1 if the class is going to be exported, @minus{}1 if it is going\n\
6212 to be imported and 0 otherwise. This function should return the\n\
6213 modified value and perform any other actions necessary to support the\n\
6214 backend's targeted operating system.",
6215 int, (tree type, int import_export), NULL)
6217 /* Returns true if constructors and destructors return "this". */
6219 (cdtor_returns_this,
6220 "This hook should return @code{true} if constructors and destructors return\n\
6221 the address of the object created/destroyed. The default is to return\n\
6224 hook_bool_void_false)
6226 /* Returns true if the key method for a class can be an inline
6227 function, so long as it is not declared inline in the class
6228 itself. Returning true is the behavior required by the Itanium C++ ABI. */
6230 (key_method_may_be_inline,
6231 "This hook returns true if the key method for a class (i.e., the method\n\
6232 which, if defined in the current translation unit, causes the virtual\n\
6233 table to be emitted) may be an inline function. Under the standard\n\
6234 Itanium C++ ABI the key method may be an inline function so long as\n\
6235 the function is not declared inline in the class definition. Under\n\
6236 some variants of the ABI, an inline function can never be the key\n\
6237 method. The default is to return @code{true}.",
6239 hook_bool_void_true)
6242 (determine_class_data_visibility,
6243 "@var{decl} is a virtual table, virtual table table, typeinfo object,\
6244 or other similar implicit class data object that will be emitted with\
6245 external linkage in this translation unit. No ELF visibility has been\
6246 explicitly specified. If the target needs to specify a visibility\
6247 other than that of the containing class, use this hook to set\
6248 @code{DECL_VISIBILITY} and @code{DECL_VISIBILITY_SPECIFIED}.",
6252 /* Returns true (the default) if virtual tables and other
6253 similar implicit class data objects are always COMDAT if they
6254 have external linkage. If this hook returns false, then
6255 class data for classes whose virtual table will be emitted in
6256 only one translation unit will not be COMDAT. */
6258 (class_data_always_comdat,
6259 "This hook returns true (the default) if virtual tables and other\n\
6260 similar implicit class data objects are always COMDAT if they have\n\
6261 external linkage. If this hook returns false, then class data for\n\
6262 classes whose virtual table will be emitted in only one translation\n\
6263 unit will not be COMDAT.",
6265 hook_bool_void_true)
6267 /* Returns true (the default) if the RTTI for the basic types,
6268 which is always defined in the C++ runtime, should be COMDAT;
6269 false if it should not be COMDAT. */
6271 (library_rtti_comdat,
6272 "This hook returns true (the default) if the RTTI information for\n\
6273 the basic types which is defined in the C++ runtime should always\n\
6274 be COMDAT, false if it should not be COMDAT.",
6276 hook_bool_void_true)
6278 /* Returns true if __aeabi_atexit should be used to register static
6282 "This hook returns true if @code{__aeabi_atexit} (as defined by the ARM EABI)\n\
6283 should be used to register static destructors when @option{-fuse-cxa-atexit}\n\
6284 is in effect. The default is to return false to use @code{__cxa_atexit}.",
6286 hook_bool_void_false)
6288 /* Returns true if target may use atexit in the same manner as
6289 __cxa_atexit to register static destructors. */
6291 (use_atexit_for_cxa_atexit,
6292 "This hook returns true if the target @code{atexit} function can be used\n\
6293 in the same manner as @code{__cxa_atexit} to register C++ static\n\
6294 destructors. This requires that @code{atexit}-registered functions in\n\
6295 shared libraries are run in the correct order when the libraries are\n\
6296 unloaded. The default is to return false.",
6298 hook_bool_void_false)
6301 (adjust_class_at_definition,
6302 "@var{type} is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has just\
6303 been defined. Use this hook to make adjustments to the class (eg, tweak\
6304 visibility or perform any other required target modifications).",
6309 (decl_mangling_context,
6310 "Return target-specific mangling context of @var{decl} or @code{NULL_TREE}.",
6311 tree, (const_tree decl),
6312 hook_tree_const_tree_null)
6314 HOOK_VECTOR_END (cxx)
6316 /* Functions and data for emulated TLS support. */
6318 #define HOOK_PREFIX "TARGET_EMUTLS_"
6319 HOOK_VECTOR (TARGET_EMUTLS, emutls)
6321 /* Name of the address and common functions. */
6324 "Contains the name of the helper function that uses a TLS control\n\
6325 object to locate a TLS instance. The default causes libgcc's\n\
6326 emulated TLS helper function to be used.",
6327 const char *, "__builtin___emutls_get_address")
6331 "Contains the name of the helper function that should be used at\n\
6332 program startup to register TLS objects that are implicitly\n\
6333 initialized to zero. If this is @code{NULL}, all TLS objects will\n\
6334 have explicit initializers. The default causes libgcc's emulated TLS\n\
6335 registration function to be used.",
6336 const char *, "__builtin___emutls_register_common")
6338 /* Prefixes for proxy variable and template. */
6341 "Contains the name of the section in which TLS control variables should\n\
6342 be placed. The default of @code{NULL} allows these to be placed in\n\
6348 "Contains the name of the section in which TLS initializers should be\n\
6349 placed. The default of @code{NULL} allows these to be placed in any\n\
6353 /* Prefixes for proxy variable and template. */
6356 "Contains the prefix to be prepended to TLS control variable names.\n\
6357 The default of @code{NULL} uses a target-specific prefix.",
6362 "Contains the prefix to be prepended to TLS initializer objects. The\n\
6363 default of @code{NULL} uses a target-specific prefix.",
6366 /* Function to generate field definitions of the proxy variable. */
6369 "Specifies a function that generates the FIELD_DECLs for a TLS control\n\
6370 object type. @var{type} is the RECORD_TYPE the fields are for and\n\
6371 @var{name} should be filled with the structure tag, if the default of\n\
6372 @code{__emutls_object} is unsuitable. The default creates a type suitable\n\
6373 for libgcc's emulated TLS function.",
6374 tree, (tree type, tree *name),
6375 default_emutls_var_fields)
6377 /* Function to initialize a proxy variable. */
6380 "Specifies a function that generates the CONSTRUCTOR to initialize a\n\
6381 TLS control object. @var{var} is the TLS control object, @var{decl}\n\
6382 is the TLS object and @var{tmpl_addr} is the address of the\n\
6383 initializer. The default initializes libgcc's emulated TLS control object.",
6384 tree, (tree var, tree decl, tree tmpl_addr),
6385 default_emutls_var_init)
6387 /* Whether we are allowed to alter the usual alignment of the
6391 "Specifies whether the alignment of TLS control variable objects is\n\
6392 fixed and should not be increased as some backends may do to optimize\n\
6393 single objects. The default is false.",
6396 /* Whether we can emit debug information for TLS vars. */
6398 (debug_form_tls_address,
6399 "Specifies whether a DWARF @code{DW_OP_form_tls_address} location descriptor\n\
6400 may be used to describe emulated TLS control objects.",
6403 HOOK_VECTOR_END (emutls)
6406 #define HOOK_PREFIX "TARGET_OPTION_"
6407 HOOK_VECTOR (TARGET_OPTION_HOOKS, target_option_hooks)
6409 /* Function to validate the attribute((target(...))) strings. If
6410 the option is validated, the hook should also fill in
6411 DECL_FUNCTION_SPECIFIC_TARGET in the function decl node. */
6414 "This hook is called to parse @code{attribute(target(\"...\"))}, which\n\
6415 allows setting target-specific options on individual functions.\n\
6416 These function-specific options may differ\n\
6417 from the options specified on the command line. The hook should return\n\
6418 @code{true} if the options are valid.\n\
6420 The hook should set the @code{DECL_FUNCTION_SPECIFIC_TARGET} field in\n\
6421 the function declaration to hold a pointer to a target-specific\n\
6422 @code{struct cl_target_option} structure.",
6423 bool, (tree fndecl, tree name, tree args, int flags),
6424 default_target_option_valid_attribute_p)
6426 /* Function to save any extra target state in the target options structure. */
6429 "This hook is called to save any additional target-specific information\n\
6430 in the @code{struct cl_target_option} structure for function-specific\n\
6431 options from the @code{struct gcc_options} structure.\n\
6432 @xref{Option file format}.",
6433 void, (struct cl_target_option *ptr, struct gcc_options *opts,
6434 struct gcc_options *opts_set), NULL)
6436 /* Function to restore any extra target state from the target options
6440 "This hook is called to restore any additional target-specific\n\
6441 information in the @code{struct cl_target_option} structure for\n\
6442 function-specific options to the @code{struct gcc_options} structure.",
6443 void, (struct gcc_options *opts, struct gcc_options *opts_set,
6444 struct cl_target_option *ptr), NULL)
6446 /* Function to update target-specific option information after being
6450 "This hook is called to update target-specific information in the\n\
6451 @code{struct cl_target_option} structure after it is streamed in from\n\
6453 void, (struct cl_target_option *ptr), NULL)
6455 /* Function to print any extra target state from the target options
6459 "This hook is called to print any additional target-specific\n\
6460 information in the @code{struct cl_target_option} structure for\n\
6461 function-specific options.",
6462 void, (FILE *file, int indent, struct cl_target_option *ptr), NULL)
6464 /* Function to parse arguments to be validated for #pragma target, and to
6465 change the state if the options are valid. If the first argument is
6466 NULL, the second argument specifies the default options to use. Return
6467 true if the options are valid, and set the current state. */
6470 "This target hook parses the options for @code{#pragma GCC target}, which\n\
6471 sets the target-specific options for functions that occur later in the\n\
6472 input stream. The options accepted should be the same as those handled by the\n\
6473 @code{TARGET_OPTION_VALID_ATTRIBUTE_P} hook.",
6474 bool, (tree args, tree pop_target),
6475 default_target_option_pragma_parse)
6477 /* Do option overrides for the target. */
6480 "Sometimes certain combinations of command options do not make sense on\n\
6481 a particular target machine. You can override the hook\n\
6482 @code{TARGET_OPTION_OVERRIDE} to take account of this. This hooks is called\n\
6483 once just after all the command options have been parsed.\n\
6485 Don't use this hook to turn on various extra optimizations for\n\
6486 @option{-O}. That is what @code{TARGET_OPTION_OPTIMIZATION} is for.\n\
6488 If you need to do something whenever the optimization level is\n\
6489 changed via the optimize attribute or pragma, see\n\
6490 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}",
6494 /* This function returns true if DECL1 and DECL2 are versions of the same
6495 function. DECL1 and DECL2 are function versions if and only if they
6496 have the same function signature and different target specific attributes,
6497 that is, they are compiled for different target machines. */
6500 "This target hook returns @code{true} if @var{DECL1} and @var{DECL2} are\n\
6501 versions of the same function. @var{DECL1} and @var{DECL2} are function\n\
6502 versions if and only if they have the same function signature and\n\
6503 different target specific attributes, that is, they are compiled for\n\
6504 different target machines.",
6505 bool, (tree decl1, tree decl2),
6506 hook_bool_tree_tree_false)
6508 /* Function to determine if one function can inline another function. */
6510 #define HOOK_PREFIX "TARGET_"
6513 "This target hook returns @code{false} if the @var{caller} function\n\
6514 cannot inline @var{callee}, based on target specific information. By\n\
6515 default, inlining is not allowed if the callee function has function\n\
6516 specific target options and the caller does not use the same options.",
6517 bool, (tree caller, tree callee),
6518 default_target_can_inline_p)
6522 "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.",
6523 void, (tree fndecl),
6526 HOOK_VECTOR_END (target_option)
6528 /* For targets that need to mark extra registers as live on entry to
6529 the function, they should define this target hook and set their
6530 bits in the bitmap passed in. */
6532 (extra_live_on_entry,
6533 "Add any hard registers to @var{regs} that are live on entry to the\n\
6534 function. This hook only needs to be defined to provide registers that\n\
6535 cannot be found by examination of FUNCTION_ARG_REGNO_P, the callee saved\n\
6536 registers, STATIC_CHAIN_INCOMING_REGNUM, STATIC_CHAIN_REGNUM,\n\
6537 TARGET_STRUCT_VALUE_RTX, FRAME_POINTER_REGNUM, EH_USES,\n\
6538 FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM.",
6539 void, (bitmap regs),
6542 /* Targets should define this target hook to mark that non-callee clobbers are
6543 present in CALL_INSN_FUNCTION_USAGE for all the calls that bind to a local
6546 (call_fusage_contains_non_callee_clobbers,
6547 "Set to true if each call that binds to a local definition explicitly\n\
6548 clobbers or sets all non-fixed registers modified by performing the call.\n\
6549 That is, by the call pattern itself, or by code that might be inserted by the\n\
6550 linker (e.g.@: stubs, veneers, branch islands), but not including those\n\
6551 modifiable by the callee. The affected registers may be mentioned explicitly\n\
6552 in the call pattern, or included as clobbers in CALL_INSN_FUNCTION_USAGE.\n\
6553 The default version of this hook is set to false. The purpose of this hook\n\
6554 is to enable the fipa-ra optimization.",
6558 /* Fill in additional registers set up by prologue into a regset. */
6560 (set_up_by_prologue,
6561 "This hook should add additional registers that are computed by the prologue\
6562 to the hard regset for shrink-wrapping optimization purposes.",
6563 void, (struct hard_reg_set_container *),
6566 /* For targets that have attributes that can affect whether a
6567 function's return statements need checking. For instance a 'naked'
6568 function attribute. */
6571 "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.",
6573 hook_bool_tree_true)
6576 #define HOOK_PREFIX "TARGET_SHRINK_WRAP_"
6577 HOOK_VECTOR (TARGET_SHRINK_WRAP_HOOKS, shrink_wrap)
6580 (get_separate_components,
6581 "This hook should return an @code{sbitmap} with the bits set for those\n\
6582 components that can be separately shrink-wrapped in the current function.\n\
6583 Return @code{NULL} if the current function should not get any separate\n\
6585 Don't define this hook if it would always return @code{NULL}.\n\
6586 If it is defined, the other hooks in this group have to be defined as well.",
6592 "This hook should return an @code{sbitmap} with the bits set for those\n\
6593 components where either the prologue component has to be executed before\n\
6594 the @code{basic_block}, or the epilogue component after it, or both.",
6595 sbitmap, (basic_block),
6599 (disqualify_components,
6600 "This hook should clear the bits in the @var{components} bitmap for those\n\
6601 components in @var{edge_components} that the target cannot handle on edge\n\
6602 @var{e}, where @var{is_prologue} says if this is for a prologue or an\n\
6604 void, (sbitmap components, edge e, sbitmap edge_components, bool is_prologue),
6608 (emit_prologue_components,
6609 "Emit prologue insns for the components indicated by the parameter.",
6614 (emit_epilogue_components,
6615 "Emit epilogue insns for the components indicated by the parameter.",
6620 (set_handled_components,
6621 "Mark the components in the parameter as handled, so that the\n\
6622 @code{prologue} and @code{epilogue} named patterns know to ignore those\n\
6623 components. The target code should not hang on to the @code{sbitmap}, it\n\
6624 will be deleted after this call.",
6628 HOOK_VECTOR_END (shrink_wrap)
6630 #define HOOK_PREFIX "TARGET_"
6632 /* Determine the type of unwind info to emit for debugging. */
6635 "This hook defines the mechanism that will be used for describing frame\n\
6636 unwind information to the debugger. Normally the hook will return\n\
6637 @code{UI_DWARF2} if DWARF 2 debug information is enabled, and\n\
6638 return @code{UI_NONE} otherwise.\n\
6640 A target may return @code{UI_DWARF2} even when DWARF 2 debug information\n\
6641 is disabled in order to always output DWARF 2 frame information.\n\
6643 A target may return @code{UI_TARGET} if it has ABI specified unwind tables.\n\
6644 This will suppress generation of the normal debug frame unwind information.",
6645 enum unwind_info_type, (void),
6646 default_debug_unwind_info)
6649 (reset_location_view, "\
6650 This hook, if defined, enables -ginternal-reset-location-views, and\n\
6651 uses its result to override cases in which the estimated min insn\n\
6652 length might be nonzero even when a PC advance (i.e., a view reset)\n\
6653 cannot be taken for granted.\n\
6655 If the hook is defined, it must return a positive value to indicate\n\
6656 the insn definitely advances the PC, and so the view number can be\n\
6657 safely assumed to be reset; a negative value to mean the insn\n\
6658 definitely does not advance the PC, and os the view number must not\n\
6659 be reset; or zero to decide based on the estimated insn length.\n\
6661 If insn length is to be regarded as reliable, set the hook to\n\
6662 @code{hook_int_rtx_insn_0}.",
6663 int, (rtx_insn *), NULL)
6665 /* The code parameter should be of type enum rtx_code but this is not
6666 defined at this time. */
6668 (canonicalize_comparison,
6669 "On some machines not all possible comparisons are defined, but you can\n\
6670 convert an invalid comparison into a valid one. For example, the Alpha\n\
6671 does not have a @code{GT} comparison, but you can use an @code{LT}\n\
6672 comparison instead and swap the order of the operands.\n\
6674 On such machines, implement this hook to do any required conversions.\n\
6675 @var{code} is the initial comparison code and @var{op0} and @var{op1}\n\
6676 are the left and right operands of the comparison, respectively. If\n\
6677 @var{op0_preserve_value} is @code{true} the implementation is not\n\
6678 allowed to change the value of @var{op0} since the value might be used\n\
6679 in RTXs which aren't comparisons. E.g. the implementation is not\n\
6680 allowed to swap operands in that case.\n\
6682 GCC will not assume that the comparison resulting from this macro is\n\
6683 valid but will see if the resulting insn matches a pattern in the\n\
6686 You need not to implement this hook if it would never change the\n\
6687 comparison code or operands.",
6688 void, (int *code, rtx *op0, rtx *op1, bool op0_preserve_value),
6689 default_canonicalize_comparison)
6692 (min_arithmetic_precision,
6693 "On some RISC architectures with 64-bit registers, the processor also\n\
6694 maintains 32-bit condition codes that make it possible to do real 32-bit\n\
6695 arithmetic, although the operations are performed on the full registers.\n\
6697 On such architectures, defining this hook to 32 tells the compiler to try\n\
6698 using 32-bit arithmetical operations setting the condition codes instead\n\
6699 of doing full 64-bit arithmetic.\n\
6701 More generally, define this hook on RISC architectures if you want the\n\
6702 compiler to try using arithmetical operations setting the condition codes\n\
6703 with a precision lower than the word precision.\n\
6705 You need not define this hook if @code{WORD_REGISTER_OPERATIONS} is not\n\
6707 unsigned int, (void), default_min_arithmetic_precision)
6710 (atomic_test_and_set_trueval,
6711 "This value should be set if the result written by\
6712 @code{atomic_test_and_set} is not exactly 1, i.e.@: the\
6713 @code{bool} @code{true}.",
6716 /* Return an unsigned int representing the alignment (in bits) of the atomic
6717 type which maps to machine MODE. This allows alignment to be overridden
6720 (atomic_align_for_mode,
6721 "If defined, this function returns an appropriate alignment in bits for an\
6722 atomic object of machine_mode @var{mode}. If 0 is returned then the\
6723 default alignment for the specified mode is used. ",
6724 unsigned int, (machine_mode mode),
6728 (atomic_assign_expand_fenv,
6729 "ISO C11 requires atomic compound assignments that may raise floating-point\
6730 exceptions to raise exceptions corresponding to the arithmetic operation\
6731 whose result was successfully stored in a compare-and-exchange sequence. \
6732 This requires code equivalent to calls to @code{feholdexcept},\
6733 @code{feclearexcept} and @code{feupdateenv} to be generated at\
6734 appropriate points in the compare-and-exchange sequence. This hook should\
6735 set @code{*@var{hold}} to an expression equivalent to the call to\
6736 @code{feholdexcept}, @code{*@var{clear}} to an expression equivalent to\
6737 the call to @code{feclearexcept} and @code{*@var{update}} to an expression\
6738 equivalent to the call to @code{feupdateenv}. The three expressions are\
6739 @code{NULL_TREE} on entry to the hook and may be left as @code{NULL_TREE}\
6740 if no code is required in a particular place. The default implementation\
6741 leaves all three expressions as @code{NULL_TREE}. The\
6742 @code{__atomic_feraiseexcept} function from @code{libatomic} may be of use\
6743 as part of the code generated in @code{*@var{update}}.",
6744 void, (tree *hold, tree *clear, tree *update),
6745 default_atomic_assign_expand_fenv)
6747 /* Leave the boolean fields at the end. */
6749 /* True if we can create zeroed data by switching to a BSS section
6750 and then using ASM_OUTPUT_SKIP to allocate the space. */
6752 (have_switchable_bss_sections,
6753 "This flag is true if we can create zeroed data by switching to a BSS\n\
6754 section and then using @code{ASM_OUTPUT_SKIP} to allocate the space.\n\
6755 This is true on most ELF targets.",
6758 /* True if "native" constructors and destructors are supported,
6759 false if we're using collect2 for the job. */
6762 "This value is true if the target supports some ``native'' method of\n\
6763 collecting constructors and destructors to be run at startup and exit.\n\
6764 It is false if we must use @command{collect2}.",
6767 /* True if thread-local storage is supported. */
6770 "Contains the value true if the target supports thread-local storage.\n\
6771 The default value is false.",
6774 /* True if a small readonly data section is supported. */
6776 (have_srodata_section,
6777 "Contains the value true if the target places read-only\n\
6778 ``small data'' into a separate section. The default value is false.",
6781 /* True if EH frame info sections should be zero-terminated. */
6783 (terminate_dw2_eh_frame_info,
6784 "Contains the value true if the target should add a zero word onto the\n\
6785 end of a Dwarf-2 frame info section when used for exception handling.\n\
6786 Default value is false if @code{EH_FRAME_SECTION_NAME} is defined, and\n\
6790 /* True if #NO_APP should be emitted at the beginning of assembly output. */
6792 (asm_file_start_app_off,
6793 "If this flag is true, the text of the macro @code{ASM_APP_OFF} will be\n\
6794 printed as the very first line in the assembly file, unless\n\
6795 @option{-fverbose-asm} is in effect. (If that macro has been defined\n\
6796 to the empty string, this variable has no effect.) With the normal\n\
6797 definition of @code{ASM_APP_OFF}, the effect is to notify the GNU\n\
6798 assembler that it need not bother stripping comments or extra\n\
6799 whitespace from its input. This allows it to work a bit faster.\n\
6801 The default is false. You should not set it to true unless you have\n\
6802 verified that your port does not generate any extra whitespace or\n\
6803 comments that will cause GAS to issue errors in NO_APP mode.",
6806 /* True if output_file_directive should be called for main_input_filename
6807 at the beginning of assembly output. */
6809 (asm_file_start_file_directive,
6810 "If this flag is true, @code{output_file_directive} will be called\n\
6811 for the primary source file, immediately after printing\n\
6812 @code{ASM_APP_OFF} (if that is enabled). Most ELF assemblers expect\n\
6813 this to be done. The default is false.",
6816 /* Returns true if we should generate exception tables for use with the
6817 ARM EABI. The effects the encoding of function exception specifications. */
6820 "This flag should be set to @code{true} on targets that use an ARM EABI\n\
6821 based unwinding library, and @code{false} on other targets. This effects\n\
6822 the format of unwinding tables, and how the unwinder in entered after\n\
6823 running a cleanup. The default is @code{false}.",
6827 (want_debug_pub_sections,
6828 "True if the @code{.debug_pubtypes} and @code{.debug_pubnames} sections\
6829 should be emitted. These sections are not used on most platforms, and\
6830 in particular GDB does not use them.",
6834 (delay_sched2, "True if sched2 is not to be run at its normal place.\n\
6835 This usually means it will be run as part of machine-specific reorg.",
6839 (delay_vartrack, "True if vartrack is not to be run at its normal place.\n\
6840 This usually means it will be run as part of machine-specific reorg.",
6844 (no_register_allocation, "True if register allocation and the passes\n\
6845 following it should not be run. Usually true only for virtual assembler\n\
6849 /* Leave the boolean fields at the end. */
6851 /* Functions related to mode switching. */
6853 #define HOOK_PREFIX "TARGET_MODE_"
6854 HOOK_VECTOR (TARGET_TOGGLE_, mode_switching)
6858 "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.",
6859 void, (int entity, int mode, int prev_mode, HARD_REG_SET regs_live), NULL)
6863 "@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}.",
6864 int, (int entity, rtx_insn *insn), NULL)
6868 "@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).",
6869 int, (int entity, int mode, rtx_insn *insn), NULL)
6873 "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.",
6874 int, (int entity), NULL)
6878 "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.",
6879 int, (int entity), NULL)
6883 "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}.",
6884 int, (int entity, int n), NULL)
6886 HOOK_VECTOR_END (mode_switching)
6889 #define HOOK_PREFIX "TARGET_MEMTAG_"
6890 HOOK_VECTOR (TARGET_MEMTAG_, memtag)
6894 "True if the backend architecture naturally supports ignoring some region\n\
6895 of pointers. This feature means that @option{-fsanitize=hwaddress} can\n\
6898 At preset, this feature does not support address spaces. It also requires\n\
6899 @code{Pmode} to be the same as @code{ptr_mode}.",
6900 bool, (), default_memtag_can_tag_addresses)
6904 "Return the size of a tag (in bits) for this platform.\n\
6906 The default returns 8.",
6907 uint8_t, (), default_memtag_tag_size)
6911 "Return the size in real memory that each byte in shadow memory refers to.\n\
6912 I.e. if a variable is @var{X} bytes long in memory, then this hook should\n\
6913 return the value @var{Y} such that the tag in shadow memory spans\n\
6914 @var{X}/@var{Y} bytes.\n\
6916 Most variables will need to be aligned to this amount since two variables\n\
6917 that are neighbors in memory and share a tag granule would need to share\n\
6920 The default returns 16.",
6921 uint8_t, (), default_memtag_granule_size)
6925 "Return an RTX representing the value of @var{untagged} but with a\n\
6926 (possibly) random tag in it.\n\
6927 Put that value into @var{target} if it is convenient to do so.\n\
6928 This function is used to generate a tagged base for the current stack frame.",
6929 rtx, (rtx untagged, rtx target), default_memtag_insert_random_tag)
6933 "Return an RTX that represents the result of adding @var{addr_offset} to\n\
6934 the address in pointer @var{base} and @var{tag_offset} to the tag in pointer\n\
6936 The resulting RTX must either be a valid memory address or be able to get\n\
6937 put into an operand with @code{force_operand}.\n\
6939 Unlike other memtag hooks, this must return an expression and not emit any\n\
6941 rtx, (rtx base, poly_int64 addr_offset, uint8_t tag_offset),
6942 default_memtag_add_tag)
6946 "Return an RTX representing @var{untagged_base} but with the tag @var{tag}.\n\
6947 Try and store this in @var{target} if convenient.\n\
6948 @var{untagged_base} is required to have a zero tag when this hook is called.\n\
6949 The default of this hook is to set the top byte of @var{untagged_base} to\n\
6951 rtx, (rtx untagged_base, rtx tag, rtx target), default_memtag_set_tag)
6955 "Return an RTX representing the tag stored in @var{tagged_pointer}.\n\
6956 Store the result in @var{target} if it is convenient.\n\
6957 The default represents the top byte of the original pointer.",
6958 rtx, (rtx tagged_pointer, rtx target), default_memtag_extract_tag)
6962 "Return an RTX representing @var{tagged_pointer} with its tag set to zero.\n\
6963 Store the result in @var{target} if convenient.\n\
6964 The default clears the top byte of the original pointer.",
6965 rtx, (rtx tagged_pointer, rtx target), default_memtag_untagged_pointer)
6967 HOOK_VECTOR_END (memtag)
6969 #define HOOK_PREFIX "TARGET_"
6971 #define DEF_TARGET_INSN(NAME, PROTO) \
6972 DEFHOOK_UNDOC (have_##NAME, "", bool, (void), false)
6973 #include "target-insns.def"
6974 #undef DEF_TARGET_INSN
6976 #define DEF_TARGET_INSN(NAME, PROTO) \
6977 DEFHOOK_UNDOC (gen_##NAME, "", rtx_insn *, PROTO, NULL)
6978 #include "target-insns.def"
6979 #undef DEF_TARGET_INSN
6981 #define DEF_TARGET_INSN(NAME, PROTO) \
6982 DEFHOOKPOD (code_for_##NAME, "*", enum insn_code, CODE_FOR_nothing)
6983 #include "target-insns.def"
6984 #undef DEF_TARGET_INSN
6987 (run_target_selftests,
6988 "If selftests are enabled, run any selftests for this target.",
6992 /* Close the 'struct gcc_target' definition. */
6993 HOOK_VECTOR_END (C90_EMPTY_HACK)