gcc/config/alpha/elf.h

   1 /* Definitions of target machine for GNU compiler, for DEC Alpha w/ELF.
   2    Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2007, 2008,
   3    2009, 2010, 2012 Free Software Foundation, Inc.
   4    Contributed by Richard Henderson (rth@tamu.edu).
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 3, or (at your option)
  11 any later version.
  12
  13 GCC is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #define OBJECT_FORMAT_ELF
  23
  24 #define DWARF2_DEBUGGING_INFO 1
  25
  26 #undef  PREFERRED_DEBUGGING_TYPE
  27 #define PREFERRED_DEBUGGING_TYPE DWARF2_DEBUG
  28
  29 #undef ASM_FINAL_SPEC
  30
  31 /* alpha/ doesn't use elfos.h for some reason.  */
  32 #define TARGET_OBJFMT_CPP_BUILTINS()            \
  33   do                                            \
  34     {                                           \
  35         builtin_define ("__ELF__");             \
  36     }                                           \
  37   while (0)
  38
  39 #undef  CC1_SPEC
  40 #define CC1_SPEC  "%{G*}"
  41
  42 #undef  ASM_SPEC
  43 #define ASM_SPEC  "%{G*} %{relax:-relax} %{!gstabs*:-no-mdebug}%{gstabs*:-mdebug}"
  44
  45 #undef  IDENT_ASM_OP
  46 #define IDENT_ASM_OP "\t.ident\t"
  47
  48 /* Output #ident as a .ident.  */
  49 #undef  ASM_OUTPUT_IDENT
  50 #define ASM_OUTPUT_IDENT(FILE, NAME) \
  51   fprintf (FILE, "%s\"%s\"\n", IDENT_ASM_OP, NAME);
  52
  53 /* This is how to allocate empty space in some section.  The .zero
  54    pseudo-op is used for this on most svr4 assemblers.  */
  55
  56 #undef  SKIP_ASM_OP
  57 #define SKIP_ASM_OP     "\t.zero\t"
  58
  59 #undef  ASM_OUTPUT_SKIP
  60 #define ASM_OUTPUT_SKIP(FILE, SIZE) \
  61   fprintf (FILE, "%s"HOST_WIDE_INT_PRINT_UNSIGNED"\n", SKIP_ASM_OP, (SIZE))
  62
  63 /* Output the label which precedes a jumptable.  Note that for all svr4
  64    systems where we actually generate jumptables (which is to say every
  65    svr4 target except i386, where we use casesi instead) we put the jump-
  66    tables into the .rodata section and since other stuff could have been
  67    put into the .rodata section prior to any given jumptable, we have to
  68    make sure that the location counter for the .rodata section gets pro-
  69    perly re-aligned prior to the actual beginning of the jump table.  */
  70
  71 #undef  ALIGN_ASM_OP
  72 #define ALIGN_ASM_OP "\t.align\t"
  73
  74 #ifndef ASM_OUTPUT_BEFORE_CASE_LABEL
  75 #define ASM_OUTPUT_BEFORE_CASE_LABEL(FILE, PREFIX, NUM, TABLE) \
  76   ASM_OUTPUT_ALIGN ((FILE), 2);
  77 #endif
  78
  79 #undef  ASM_OUTPUT_CASE_LABEL
  80 #define ASM_OUTPUT_CASE_LABEL(FILE, PREFIX, NUM, JUMPTABLE)             \
  81   do {                                                                  \
  82     ASM_OUTPUT_BEFORE_CASE_LABEL (FILE, PREFIX, NUM, JUMPTABLE)         \
  83     (*targetm.asm_out.internal_label) (FILE, PREFIX, NUM);                      \
  84   } while (0)
  85
  86 /* The standard SVR4 assembler seems to require that certain builtin
  87    library routines (e.g. .udiv) be explicitly declared as .globl
  88    in each assembly file where they are referenced.  */
  89
  90 #undef  ASM_OUTPUT_EXTERNAL_LIBCALL
  91 #define ASM_OUTPUT_EXTERNAL_LIBCALL(FILE, FUN)                          \
  92   (*targetm.asm_out.globalize_label) (FILE, XSTR (FUN, 0))
  93
  94 /* This says how to output assembler code to declare an
  95    uninitialized external linkage data object.  Under SVR4,
  96    the linker seems to want the alignment of data objects
  97    to depend on their types.  We do exactly that here.  */
  98
  99 #undef  COMMON_ASM_OP
 100 #define COMMON_ASM_OP   "\t.comm\t"
 101
 102 #undef  ASM_OUTPUT_ALIGNED_COMMON
 103 #define ASM_OUTPUT_ALIGNED_COMMON(FILE, NAME, SIZE, ALIGN)              \
 104 do {                                                                    \
 105   fprintf ((FILE), "%s", COMMON_ASM_OP);                                \
 106   assemble_name ((FILE), (NAME));                                       \
 107   fprintf ((FILE), "," HOST_WIDE_INT_PRINT_UNSIGNED ",%u\n", (SIZE), (ALIGN) / BITS_PER_UNIT);  \
 108 } while (0)
 109
 110 /* This says how to output assembler code to declare an
 111    uninitialized internal linkage data object.  Under SVR4,
 112    the linker seems to want the alignment of data objects
 113    to depend on their types.  We do exactly that here.  */
 114
 115 #undef  ASM_OUTPUT_ALIGNED_LOCAL
 116 #define ASM_OUTPUT_ALIGNED_LOCAL(FILE, NAME, SIZE, ALIGN)               \
 117 do {                                                                    \
 118   if ((SIZE) <= (unsigned HOST_WIDE_INT) g_switch_value)                \
 119     switch_to_section (sbss_section);                                   \
 120   else                                                                  \
 121     switch_to_section (bss_section);                                    \
 122   ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "object");                     \
 123   if (!flag_inhibit_size_directive)                                     \
 124     ASM_OUTPUT_SIZE_DIRECTIVE (FILE, NAME, SIZE);                       \
 125   ASM_OUTPUT_ALIGN ((FILE), exact_log2((ALIGN) / BITS_PER_UNIT));       \
 126   ASM_OUTPUT_LABEL(FILE, NAME);                                         \
 127   ASM_OUTPUT_SKIP((FILE), (SIZE) ? (SIZE) : 1);                         \
 128 } while (0)
 129
 130 /* This says how to output assembler code to declare an
 131    uninitialized external linkage data object.  */
 132
 133 #undef  ASM_OUTPUT_ALIGNED_BSS
 134 #define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN)           \
 135 do {                                                                    \
 136   ASM_OUTPUT_ALIGNED_LOCAL (FILE, NAME, SIZE, ALIGN);                   \
 137 } while (0)
 138
 139 /* The biggest alignment supported by ELF in bits. 32-bit ELF
 140    supports section alignment up to (0x80000000 * 8), while
 141    64-bit ELF supports (0x8000000000000000 * 8). If this macro
 142    is not defined, the default is the largest alignment supported
 143    by 32-bit ELF and representable on a 32-bit host. Use this
 144    macro to limit the alignment which can be specified using
 145    the `__attribute__ ((aligned (N)))' construct.
 146
 147    This value is really 2^63.  Since gcc figures the alignment in bits,
 148    we could only potentially get to 2^60 on suitable hosts.  Due to other
 149    considerations in varasm, we must restrict this to what fits in an int.  */
 150
 151 #undef  MAX_OFILE_ALIGNMENT
 152 #define MAX_OFILE_ALIGNMENT (((unsigned int) 1 << 28) * 8)
 153
 154 /* This is the pseudo-op used to generate a contiguous sequence of byte
 155    values from a double-quoted string WITHOUT HAVING A TERMINATING NUL
 156    AUTOMATICALLY APPENDED.  This is the same for most svr4 assemblers.  */
 157
 158 #undef  ASCII_DATA_ASM_OP
 159 #define ASCII_DATA_ASM_OP       "\t.ascii\t"
 160
 161 #undef  READONLY_DATA_SECTION_ASM_OP
 162 #define READONLY_DATA_SECTION_ASM_OP    "\t.section\t.rodata"
 163 #undef  BSS_SECTION_ASM_OP
 164 #define BSS_SECTION_ASM_OP      "\t.section\t.bss"
 165 #undef  SBSS_SECTION_ASM_OP
 166 #define SBSS_SECTION_ASM_OP     "\t.section\t.sbss,\"aw\""
 167 #undef  SDATA_SECTION_ASM_OP
 168 #define SDATA_SECTION_ASM_OP    "\t.section\t.sdata,\"aw\""
 169
 170 /* On svr4, we *do* have support for the .init and .fini sections, and we
 171    can put stuff in there to be executed before and after `main'.  We let
 172    crtstuff.c and other files know this by defining the following symbols.
 173    The definitions say how to change sections to the .init and .fini
 174    sections.  This is the same for all known svr4 assemblers.  */
 175
 176 #undef  INIT_SECTION_ASM_OP
 177 #define INIT_SECTION_ASM_OP     "\t.section\t.init"
 178 #undef  FINI_SECTION_ASM_OP
 179 #define FINI_SECTION_ASM_OP     "\t.section\t.fini"
 180
 181 #ifdef HAVE_GAS_SUBSECTION_ORDERING
 182
 183 #define ASM_SECTION_START_OP    "\t.subsection\t-1"
 184
 185 /* Output assembly directive to move to the beginning of current section.  */
 186 #define ASM_OUTPUT_SECTION_START(FILE)  \
 187   fprintf ((FILE), "%s\n", ASM_SECTION_START_OP)
 188
 189 #endif
 190
 191 /* Switch into a generic section.  */
 192 #define TARGET_ASM_NAMED_SECTION  default_elf_asm_named_section
 193 #define TARGET_ASM_SELECT_SECTION  default_elf_select_section
 194
 195 #define MAKE_DECL_ONE_ONLY(DECL) (DECL_WEAK (DECL) = 1)
 196
 197 /* Define the strings used for the special svr4 .type and .size directives.
 198    These strings generally do not vary from one system running svr4 to
 199    another, but if a given system (e.g. m88k running svr) needs to use
 200    different pseudo-op names for these, they may be overridden in the
 201    file which includes this one.  */
 202
 203 #undef  TYPE_ASM_OP
 204 #define TYPE_ASM_OP     "\t.type\t"
 205 #undef  SIZE_ASM_OP
 206 #define SIZE_ASM_OP     "\t.size\t"
 207
 208 /* This is how we tell the assembler that a symbol is weak.  */
 209
 210 #undef  ASM_WEAKEN_LABEL
 211 #define ASM_WEAKEN_LABEL(FILE, NAME) \
 212   do { fputs ("\t.weak\t", FILE); assemble_name (FILE, NAME); \
 213        fputc ('\n', FILE); } while (0)
 214
 215 /* This is how we tell the assembler that two symbols have the same value.  */
 216
 217 #undef  ASM_OUTPUT_DEF
 218 #define ASM_OUTPUT_DEF(FILE, ALIAS, NAME)                       \
 219   do {                                                          \
 220     assemble_name(FILE, ALIAS);                                 \
 221     fputs(" = ", FILE);                                         \
 222     assemble_name(FILE, NAME);                                  \
 223     fputc('\n', FILE);                                          \
 224   } while (0)
 225
 226 #undef  ASM_OUTPUT_DEF_FROM_DECLS
 227 #define ASM_OUTPUT_DEF_FROM_DECLS(FILE, DECL, TARGET)           \
 228   do {                                                          \
 229     const char *alias = XSTR (XEXP (DECL_RTL (DECL), 0), 0);    \
 230     const char *name = IDENTIFIER_POINTER (TARGET);             \
 231     if (TREE_CODE (DECL) == FUNCTION_DECL)                      \
 232       {                                                         \
 233         fputc ('$', FILE);                                      \
 234         assemble_name (FILE, alias);                            \
 235         fputs ("..ng = $", FILE);                               \
 236         assemble_name (FILE, name);                             \
 237         fputs ("..ng\n", FILE);                                 \
 238       }                                                         \
 239     assemble_name(FILE, alias);                                 \
 240     fputs(" = ", FILE);                                         \
 241     assemble_name(FILE, name);                                  \
 242     fputc('\n', FILE);                                          \
 243   } while (0)
 244
 245 /* The following macro defines the format used to output the second
 246    operand of the .type assembler directive.  Different svr4 assemblers
 247    expect various different forms for this operand.  The one given here
 248    is just a default.  You may need to override it in your machine-
 249    specific tm.h file (depending upon the particulars of your assembler).  */
 250
 251 #undef  TYPE_OPERAND_FMT
 252 #define TYPE_OPERAND_FMT        "@%s"
 253
 254 /* Write the extra assembler code needed to declare a function's result.
 255    Most svr4 assemblers don't require any special declaration of the
 256    result value, but there are exceptions.  */
 257
 258 #ifndef ASM_DECLARE_RESULT
 259 #define ASM_DECLARE_RESULT(FILE, RESULT)
 260 #endif
 261
 262 /* These macros generate the special .type and .size directives which
 263    are used to set the corresponding fields of the linker symbol table
 264    entries in an ELF object file under SVR4.  These macros also output
 265    the starting labels for the relevant functions/objects.  */
 266
 267 /* Write the extra assembler code needed to declare an object properly.  */
 268
 269 #ifdef HAVE_GAS_GNU_UNIQUE_OBJECT
 270 #define USE_GNU_UNIQUE_OBJECT 1
 271 #else
 272 #define USE_GNU_UNIQUE_OBJECT 0
 273 #endif
 274
 275 #undef  ASM_DECLARE_OBJECT_NAME
 276 #define ASM_DECLARE_OBJECT_NAME(FILE, NAME, DECL)                       \
 277   do {                                                                  \
 278     HOST_WIDE_INT size;                                                 \
 279                                                                         \
 280     /* For template static data member instantiations or                \
 281        inline fn local statics and their guard variables, use           \
 282        gnu_unique_object so that they will be combined even under       \
 283        RTLD_LOCAL.  Don't use gnu_unique_object for typeinfo,           \
 284        vtables and other read-only artificial decls.  */                \
 285     if (USE_GNU_UNIQUE_OBJECT   && DECL_ONE_ONLY (DECL)                 \
 286         && (!DECL_ARTIFICIAL (DECL) || !TREE_READONLY (DECL)))          \
 287       ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "gnu_unique_object");      \
 288     else                                                                \
 289       ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "object");                 \
 290                                                                         \
 291     size_directive_output = 0;                                          \
 292     if (!flag_inhibit_size_directive                                    \
 293         && (DECL) && DECL_SIZE (DECL))                                  \
 294       {                                                                 \
 295         size_directive_output = 1;                                      \
 296         size = int_size_in_bytes (TREE_TYPE (DECL));                    \
 297         ASM_OUTPUT_SIZE_DIRECTIVE (FILE, NAME, size);                   \
 298       }                                                                 \
 299                                                                         \
 300     ASM_OUTPUT_LABEL (FILE, NAME);                                      \
 301   } while (0)
 302
 303 /* Output the size directive for a decl in rest_of_decl_compilation
 304    in the case where we did not do so before the initializer.
 305    Once we find the error_mark_node, we know that the value of
 306    size_directive_output was set
 307    by ASM_DECLARE_OBJECT_NAME when it was run for the same decl.  */
 308
 309 #undef  ASM_FINISH_DECLARE_OBJECT
 310 #define ASM_FINISH_DECLARE_OBJECT(FILE, DECL, TOP_LEVEL, AT_END)        \
 311   do {                                                                  \
 312     const char *name = XSTR (XEXP (DECL_RTL (DECL), 0), 0);             \
 313     HOST_WIDE_INT size;                                                 \
 314     if (!flag_inhibit_size_directive                                    \
 315         && DECL_SIZE (DECL)                                             \
 316         && ! AT_END && TOP_LEVEL                                        \
 317         && DECL_INITIAL (DECL) == error_mark_node                       \
 318         && !size_directive_output                                       \
 319         && (size = int_size_in_bytes (TREE_TYPE (DECL))) > 0)           \
 320       {                                                                 \
 321         size_directive_output = 1;                                      \
 322         ASM_OUTPUT_SIZE_DIRECTIVE (FILE, name, size);                   \
 323       }                                                                 \
 324   } while (0)
 325
 326 /* A table of bytes codes used by the ASM_OUTPUT_ASCII and
 327    ASM_OUTPUT_LIMITED_STRING macros.  Each byte in the table
 328    corresponds to a particular byte value [0..255].  For any
 329    given byte value, if the value in the corresponding table
 330    position is zero, the given character can be output directly.
 331    If the table value is 1, the byte must be output as a \ooo
 332    octal escape.  If the tables value is anything else, then the
 333    byte value should be output as a \ followed by the value
 334    in the table.  Note that we can use standard UN*X escape
 335    sequences for many control characters, but we don't use
 336    \a to represent BEL because some svr4 assemblers (e.g. on
 337    the i386) don't know about that.  Also, we don't use \v
 338    since some versions of gas, such as 2.2 did not accept it.  */
 339
 340 #undef  ELF_ASCII_ESCAPES
 341 #define ELF_ASCII_ESCAPES \
 342 "\1\1\1\1\1\1\1\1btn\1fr\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\
 343 \0\0\"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\
 344 \0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\\\0\0\0\
 345 \0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\1\
 346 \1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\
 347 \1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\
 348 \1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\
 349 \1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1"
 350
 351 /* Some svr4 assemblers have a limit on the number of characters which
 352    can appear in the operand of a .string directive.  If your assembler
 353    has such a limitation, you should define STRING_LIMIT to reflect that
 354    limit.  Note that at least some svr4 assemblers have a limit on the
 355    actual number of bytes in the double-quoted string, and that they
 356    count each character in an escape sequence as one byte.  Thus, an
 357    escape sequence like \377 would count as four bytes.
 358
 359    If your target assembler doesn't support the .string directive, you
 360    should define this to zero.  */
 361
 362 #undef  ELF_STRING_LIMIT
 363 #define ELF_STRING_LIMIT        ((unsigned) 256)
 364
 365 #undef  STRING_ASM_OP
 366 #define STRING_ASM_OP   "\t.string\t"
 367
 368 /* Provide a STARTFILE_SPEC appropriate for ELF.  Here we add the
 369    (even more) magical crtbegin.o file which provides part of the
 370    support for getting C++ file-scope static object constructed
 371    before entering `main'.  */
 372
 373 #undef  STARTFILE_SPEC
 374 #ifdef HAVE_LD_PIE
 375 #define STARTFILE_SPEC \
 376   "%{!shared: %{pg|p:gcrt1.o%s;pie:Scrt1.o%s;:crt1.o%s}}\
 377    crti.o%s %{static:crtbeginT.o%s;shared|pie:crtbeginS.o%s;:crtbegin.o%s}"
 378 #else
 379 #define STARTFILE_SPEC \
 380   "%{!shared: %{pg|p:gcrt1.o%s;:crt1.o%s}}\
 381    crti.o%s %{static:crtbeginT.o%s;shared|pie:crtbeginS.o%s;:crtbegin.o%s}"
 382 #endif
 383
 384 /* Provide a ENDFILE_SPEC appropriate for ELF.  Here we tack on the
 385    magical crtend.o file which provides part of the support for
 386    getting C++ file-scope static object constructed before entering
 387    `main', followed by a normal ELF "finalizer" file, `crtn.o'.  */
 388
 389 #undef  ENDFILE_SPEC
 390 #define ENDFILE_SPEC \
 391   "%{Ofast|ffast-math|funsafe-math-optimizations:crtfastmath.o%s} \
 392    %{shared|pie:crtendS.o%s;:crtend.o%s} crtn.o%s"
 393
 394 /* Select a format to encode pointers in exception handling data.  CODE
 395    is 0 for data, 1 for code labels, 2 for function pointers.  GLOBAL is
 396    true if the symbol may be affected by dynamic relocations.
 397
 398    Since application size is already constrained to <2GB by the form of
 399    the ldgp relocation, we can use a 32-bit pc-relative relocation to
 400    static data.  Dynamic data is accessed indirectly to allow for read
 401    only EH sections.  */
 402 #define ASM_PREFERRED_EH_DATA_FORMAT(CODE,GLOBAL)       \
 403   (((GLOBAL) ? DW_EH_PE_indirect : 0) | DW_EH_PE_pcrel | DW_EH_PE_sdata4)
 404
 405 /* If defined, a C statement to be executed just prior to the output of
 406    assembler code for INSN.  */
 407 #define FINAL_PRESCAN_INSN(INSN, OPVEC, NOPERANDS)      \
 408  (alpha_this_literal_sequence_number = 0,               \
 409   alpha_this_gpdisp_sequence_number = 0)
 410 extern int alpha_this_literal_sequence_number;
 411 extern int alpha_this_gpdisp_sequence_number;
 412
 413 /* Since the bits of the _init and _fini function is spread across
 414    many object files, each potentially with its own GP, we must assume
 415    we need to load our GP.  Further, the .init/.fini section can
 416    easily be more than 4MB away from the function to call so we can't
 417    use bsr.  */
 418 #define CRT_CALL_STATIC_FUNCTION(SECTION_OP, FUNC)      \
 419    asm (SECTION_OP "\n"                                 \
 420 "       br $29,1f\n"                                    \
 421 "1:     ldgp $29,0($29)\n"                              \
 422 "       unop\n"                                         \
 423 "       jsr $26," USER_LABEL_PREFIX #FUNC "\n"          \
 424 "       .align 3\n"                                     \
 425 "       .previous");
 426
 427 /* If we have the capability create headers for efficient EH lookup.
 428    As of Jan 2002, only glibc 2.2.4 can actually make use of this, but
 429    I imagine that other systems will catch up.  In the meantime, it
 430    doesn't harm to make sure that the data exists to be used later.  */
 431 #if defined(HAVE_LD_EH_FRAME_HDR)
 432 #define LINK_EH_SPEC "%{!static:--eh-frame-hdr} "
 433 #endif
 434
 435 /* A C statement (sans semicolon) to output to the stdio stream STREAM
 436    any text necessary for declaring the name of an external symbol
 437    named NAME which is referenced in this compilation but not defined.
 438    It is needed to properly support non-default visibility.  */
 439
 440 #ifndef ASM_OUTPUT_EXTERNAL
 441 #define ASM_OUTPUT_EXTERNAL(FILE, DECL, NAME) \
 442   default_elf_asm_output_external (FILE, DECL, NAME)
 443 #endif