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
   3    Free Software Foundation, Inc.
   4    Contributed by Richard Henderson (rth@tamu.edu).
   5
   6 This file is part of GNU CC.
   7
   8 GNU CC 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 2, or (at your option)
  11 any later version.
  12
  13 GNU CC 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 GNU CC; see the file COPYING.  If not, write to
  20 the Free Software Foundation, 59 Temple Place - Suite 330,
  21 Boston, MA 02111-1307, USA.    */
  22
  23 #undef OBJECT_FORMAT_COFF
  24 #undef EXTENDED_COFF
  25 #define OBJECT_FORMAT_ELF
  26
  27 /* ??? Move all SDB stuff from alpha.h to osf.h.  */
  28 #undef SDB_DEBUGGING_INFO
  29
  30 #define DBX_DEBUGGING_INFO
  31 #define DWARF2_DEBUGGING_INFO
  32
  33 #undef  PREFERRED_DEBUGGING_TYPE
  34 #define PREFERRED_DEBUGGING_TYPE DWARF2_DEBUG
  35
  36 #undef ASM_FINAL_SPEC
  37
  38 #undef  CPP_SUBTARGET_SPEC
  39 #define CPP_SUBTARGET_SPEC "-D__ELF__"
  40
  41 #undef  CC1_SPEC
  42 #define CC1_SPEC  "%{G*}"
  43
  44 #undef  ASM_SPEC
  45 #define ASM_SPEC  "%{G*} %{relax:-relax} %{!gstabs*:-no-mdebug}%{gstabs*:-mdebug}"
  46
  47 /* Output at beginning of assembler file.  */
  48 #undef  ASM_FILE_START
  49 #define ASM_FILE_START(FILE)                                    \
  50 do {                                                            \
  51   if (write_symbols == DBX_DEBUG)                               \
  52     {                                                           \
  53       alpha_write_verstamp (FILE);                              \
  54       output_file_directive (FILE, main_input_filename);        \
  55     }                                                           \
  56   fprintf (FILE, "\t.set noat\n");                              \
  57   fprintf (FILE, "\t.set noreorder\n");                         \
  58   if (TARGET_EXPLICIT_RELOCS)                                   \
  59     fprintf (FILE, "\t.set nomacro\n");                         \
  60   if (TARGET_BWX | TARGET_MAX | TARGET_FIX | TARGET_CIX)        \
  61     {                                                           \
  62       fprintf (FILE, "\t.arch %s\n",                            \
  63                (TARGET_CPU_EV6 ? "ev6"                          \
  64                 : TARGET_MAX ? "pca56" : "ev56"));              \
  65     }                                                           \
  66 } while (0)
  67
  68 #undef  IDENT_ASM_OP
  69 #define IDENT_ASM_OP "\t.ident\t"
  70
  71 /* Allow #sccs in preprocessor.  */
  72 #define SCCS_DIRECTIVE
  73
  74 /* Output #ident as a .ident.  */
  75 #undef  ASM_OUTPUT_IDENT
  76 #define ASM_OUTPUT_IDENT(FILE, NAME) \
  77   fprintf (FILE, "%s\"%s\"\n", IDENT_ASM_OP, NAME);
  78
  79 /* This is how to allocate empty space in some section.  The .zero
  80    pseudo-op is used for this on most svr4 assemblers.  */
  81
  82 #undef  SKIP_ASM_OP
  83 #define SKIP_ASM_OP     "\t.zero\t"
  84
  85 #undef  ASM_OUTPUT_SKIP
  86 #define ASM_OUTPUT_SKIP(FILE, SIZE) \
  87   fprintf (FILE, "%s%u\n", SKIP_ASM_OP, (SIZE))
  88
  89 /* Output the label which precedes a jumptable.  Note that for all svr4
  90    systems where we actually generate jumptables (which is to say every
  91    svr4 target except i386, where we use casesi instead) we put the jump-
  92    tables into the .rodata section and since other stuff could have been
  93    put into the .rodata section prior to any given jumptable, we have to
  94    make sure that the location counter for the .rodata section gets pro-
  95    perly re-aligned prior to the actual beginning of the jump table.  */
  96
  97 #undef  ALIGN_ASM_OP
  98 #define ALIGN_ASM_OP "\t.align\t"
  99
 100 #ifndef ASM_OUTPUT_BEFORE_CASE_LABEL
 101 #define ASM_OUTPUT_BEFORE_CASE_LABEL(FILE, PREFIX, NUM, TABLE) \
 102   ASM_OUTPUT_ALIGN ((FILE), 2);
 103 #endif
 104
 105 #undef  ASM_OUTPUT_CASE_LABEL
 106 #define ASM_OUTPUT_CASE_LABEL(FILE, PREFIX, NUM, JUMPTABLE)             \
 107   do {                                                                  \
 108     ASM_OUTPUT_BEFORE_CASE_LABEL (FILE, PREFIX, NUM, JUMPTABLE)         \
 109     ASM_OUTPUT_INTERNAL_LABEL (FILE, PREFIX, NUM);                      \
 110   } while (0)
 111
 112 /* The standard SVR4 assembler seems to require that certain builtin
 113    library routines (e.g. .udiv) be explicitly declared as .globl
 114    in each assembly file where they are referenced.  */
 115
 116 #undef  ASM_OUTPUT_EXTERNAL_LIBCALL
 117 #define ASM_OUTPUT_EXTERNAL_LIBCALL(FILE, FUN)                          \
 118   ASM_GLOBALIZE_LABEL (FILE, XSTR (FUN, 0))
 119
 120 /* This says how to output assembler code to declare an
 121    uninitialized external linkage data object.  Under SVR4,
 122    the linker seems to want the alignment of data objects
 123    to depend on their types.  We do exactly that here.  */
 124
 125 #undef  COMMON_ASM_OP
 126 #define COMMON_ASM_OP   "\t.comm\t"
 127
 128 #undef  ASM_OUTPUT_ALIGNED_COMMON
 129 #define ASM_OUTPUT_ALIGNED_COMMON(FILE, NAME, SIZE, ALIGN)              \
 130 do {                                                                    \
 131   fprintf ((FILE), "%s", COMMON_ASM_OP);                                \
 132   assemble_name ((FILE), (NAME));                                       \
 133   fprintf ((FILE), ",%u,%u\n", (SIZE), (ALIGN) / BITS_PER_UNIT);        \
 134 } while (0)
 135
 136 /* This says how to output assembler code to declare an
 137    uninitialized internal linkage data object.  Under SVR4,
 138    the linker seems to want the alignment of data objects
 139    to depend on their types.  We do exactly that here.  */
 140
 141 #undef  ASM_OUTPUT_ALIGNED_LOCAL
 142 #define ASM_OUTPUT_ALIGNED_LOCAL(FILE, NAME, SIZE, ALIGN)               \
 143 do {                                                                    \
 144   if ((SIZE) <= g_switch_value)                                         \
 145     sbss_section();                                                     \
 146   else                                                                  \
 147     bss_section();                                                      \
 148   fprintf (FILE, "%s", TYPE_ASM_OP);                                    \
 149   assemble_name (FILE, NAME);                                           \
 150   putc (',', FILE);                                                     \
 151   fprintf (FILE, TYPE_OPERAND_FMT, "object");                           \
 152   putc ('\n', FILE);                                                    \
 153   if (!flag_inhibit_size_directive)                                     \
 154     {                                                                   \
 155       fprintf (FILE, "%s", SIZE_ASM_OP);                                \
 156       assemble_name (FILE, NAME);                                       \
 157       fprintf (FILE, ",%d\n", (SIZE));                                  \
 158     }                                                                   \
 159   ASM_OUTPUT_ALIGN ((FILE), exact_log2((ALIGN) / BITS_PER_UNIT));       \
 160   ASM_OUTPUT_LABEL(FILE, NAME);                                         \
 161   ASM_OUTPUT_SKIP((FILE), (SIZE));                                      \
 162 } while (0)
 163
 164 /* This says how to output assembler code to declare an
 165    uninitialized external linkage data object.  */
 166
 167 #undef  ASM_OUTPUT_ALIGNED_BSS
 168 #define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN)           \
 169 do {                                                                    \
 170   ASM_GLOBALIZE_LABEL (FILE, NAME);                                     \
 171   ASM_OUTPUT_ALIGNED_LOCAL (FILE, NAME, SIZE, ALIGN);                   \
 172 } while (0)
 173
 174 /* Biggest alignment supported by the object file format of this
 175    machine.  Use this macro to limit the alignment which can be
 176    specified using the `__attribute__ ((aligned (N)))' construct.  If
 177    not defined, the default value is `BIGGEST_ALIGNMENT'.
 178
 179    This value is really 2^63.  Since gcc figures the alignment in bits,
 180    we could only potentially get to 2^60 on suitible hosts.  Due to other
 181    considerations in varasm, we must restrict this to what fits in an int.  */
 182
 183 #undef  MAX_OFILE_ALIGNMENT
 184 #define MAX_OFILE_ALIGNMENT \
 185   (1 << (HOST_BITS_PER_INT < 64 ? HOST_BITS_PER_INT - 2 : 62))
 186
 187 /* This is the pseudo-op used to generate a contiguous sequence of byte
 188    values from a double-quoted string WITHOUT HAVING A TERMINATING NUL
 189    AUTOMATICALLY APPENDED.  This is the same for most svr4 assemblers.  */
 190
 191 #undef  ASCII_DATA_ASM_OP
 192 #define ASCII_DATA_ASM_OP       "\t.ascii\t"
 193
 194 #undef  READONLY_DATA_SECTION_ASM_OP
 195 #define READONLY_DATA_SECTION_ASM_OP    "\t.section\t.rodata"
 196 #undef  BSS_SECTION_ASM_OP
 197 #define BSS_SECTION_ASM_OP      "\t.section\t.bss"
 198 #undef  SBSS_SECTION_ASM_OP
 199 #define SBSS_SECTION_ASM_OP     "\t.section\t.sbss,\"aw\""
 200 #undef  SDATA_SECTION_ASM_OP
 201 #define SDATA_SECTION_ASM_OP    "\t.section\t.sdata,\"aw\""
 202
 203 /* On svr4, we *do* have support for the .init and .fini sections, and we
 204    can put stuff in there to be executed before and after `main'.  We let
 205    crtstuff.c and other files know this by defining the following symbols.
 206    The definitions say how to change sections to the .init and .fini
 207    sections.  This is the same for all known svr4 assemblers.  */
 208
 209 #undef  INIT_SECTION_ASM_OP
 210 #define INIT_SECTION_ASM_OP     "\t.section\t.init"
 211 #undef  FINI_SECTION_ASM_OP
 212 #define FINI_SECTION_ASM_OP     "\t.section\t.fini"
 213
 214 #ifdef HAVE_GAS_SUBSECTION_ORDERING
 215
 216 #define ASM_SECTION_START_OP    "\t.subsection\t-1"
 217
 218 /* Output assembly directive to move to the beginning of current section.  */
 219 #define ASM_OUTPUT_SECTION_START(FILE)  \
 220   fprintf ((FILE), "%s\n", ASM_SECTION_START_OP)
 221
 222 #endif
 223
 224 /* A default list of other sections which we might be "in" at any given
 225    time.  For targets that use additional sections (e.g. .tdesc) you
 226    should override this definition in the target-specific file which
 227    includes this file.  */
 228
 229 #undef  EXTRA_SECTIONS
 230 #define EXTRA_SECTIONS in_sbss, in_sdata
 231
 232 /* A default list of extra section function definitions.  For targets
 233    that use additional sections (e.g. .tdesc) you should override this
 234    definition in the target-specific file which includes this file.  */
 235
 236 #undef  EXTRA_SECTION_FUNCTIONS
 237 #define EXTRA_SECTION_FUNCTIONS                                         \
 238   SECTION_FUNCTION_TEMPLATE(sbss_section, in_sbss, SBSS_SECTION_ASM_OP) \
 239   SECTION_FUNCTION_TEMPLATE(sdata_section, in_sdata, SDATA_SECTION_ASM_OP)
 240
 241 extern void sbss_section                PARAMS ((void));
 242 extern void sdata_section               PARAMS ((void));
 243
 244 #undef  SECTION_FUNCTION_TEMPLATE
 245 #define SECTION_FUNCTION_TEMPLATE(FN, ENUM, OP) \
 246 void FN ()                                      \
 247 {                                               \
 248   if (in_section != ENUM)                       \
 249     {                                           \
 250       fprintf (asm_out_file, "%s\n", OP);       \
 251       in_section = ENUM;                        \
 252     }                                           \
 253 }
 254
 255 /* Switch into a generic section.  */
 256 #define TARGET_ASM_NAMED_SECTION  default_elf_asm_named_section
 257 #define TARGET_ASM_SELECT_SECTION  default_elf_select_section
 258
 259 #define MAKE_DECL_ONE_ONLY(DECL) (DECL_WEAK (DECL) = 1)
 260
 261 /* A C statement or statements to switch to the appropriate
 262    section for output of RTX in mode MODE.  RTX is some kind
 263    of constant in RTL.  The argument MODE is redundant except
 264    in the case of a `const_int' rtx.  Currently, these always
 265    go into the const section.  */
 266
 267 #undef  SELECT_RTX_SECTION
 268 #define SELECT_RTX_SECTION(MODE, RTX, ALIGN)                            \
 269 do {                                                                    \
 270   if (TARGET_SMALL_DATA && GET_MODE_SIZE (MODE) <= g_switch_value)      \
 271      /* ??? Consider .sdata.{lit4,lit8} as SHF_MERGE|SHF_ALPHA_GPREL.  */ \
 272     sdata_section ();                                                   \
 273   else                                                                  \
 274     mergeable_constant_section((MODE), (ALIGN), 0);                     \
 275 } while (0)
 276
 277 /* Define the strings used for the special svr4 .type and .size directives.
 278    These strings generally do not vary from one system running svr4 to
 279    another, but if a given system (e.g. m88k running svr) needs to use
 280    different pseudo-op names for these, they may be overridden in the
 281    file which includes this one.  */
 282
 283 #undef  TYPE_ASM_OP
 284 #define TYPE_ASM_OP     "\t.type\t"
 285 #undef  SIZE_ASM_OP
 286 #define SIZE_ASM_OP     "\t.size\t"
 287
 288 /* This is how we tell the assembler that a symbol is weak.  */
 289
 290 #undef  ASM_WEAKEN_LABEL
 291 #define ASM_WEAKEN_LABEL(FILE, NAME) \
 292   do { fputs ("\t.weak\t", FILE); assemble_name (FILE, NAME); \
 293        fputc ('\n', FILE); } while (0)
 294
 295 /* This is how we tell the assembler that two symbols have the same value.  */
 296
 297 #undef  ASM_OUTPUT_DEF
 298 #define ASM_OUTPUT_DEF(FILE, ALIAS, NAME)                       \
 299   do {                                                          \
 300     assemble_name(FILE, ALIAS);                                 \
 301     fputs(" = ", FILE);                                         \
 302     assemble_name(FILE, NAME);                                  \
 303     fputc('\n', FILE);                                          \
 304   } while (0)
 305
 306 #undef  ASM_OUTPUT_DEF_FROM_DECLS
 307 #define ASM_OUTPUT_DEF_FROM_DECLS(FILE, DECL, TARGET)           \
 308   do {                                                          \
 309     const char *alias = XSTR (XEXP (DECL_RTL (DECL), 0), 0);    \
 310     const char *name = IDENTIFIER_POINTER (TARGET);             \
 311     if (TREE_CODE (DECL) == FUNCTION_DECL)                      \
 312       {                                                         \
 313         fputc ('$', FILE);                                      \
 314         assemble_name (FILE, alias);                            \
 315         fputs ("..ng = $", FILE);                               \
 316         assemble_name (FILE, name);                             \
 317         fputs ("..ng\n", FILE);                                 \
 318       }                                                         \
 319     assemble_name(FILE, alias);                                 \
 320     fputs(" = ", FILE);                                         \
 321     assemble_name(FILE, name);                                  \
 322     fputc('\n', FILE);                                          \
 323   } while (0)
 324
 325 /* The following macro defines the format used to output the second
 326    operand of the .type assembler directive.  Different svr4 assemblers
 327    expect various different forms for this operand.  The one given here
 328    is just a default.  You may need to override it in your machine-
 329    specific tm.h file (depending upon the particulars of your assembler).  */
 330
 331 #undef  TYPE_OPERAND_FMT
 332 #define TYPE_OPERAND_FMT        "@%s"
 333
 334 /* Write the extra assembler code needed to declare a function's result.
 335    Most svr4 assemblers don't require any special declaration of the
 336    result value, but there are exceptions.  */
 337
 338 #ifndef ASM_DECLARE_RESULT
 339 #define ASM_DECLARE_RESULT(FILE, RESULT)
 340 #endif
 341
 342 /* These macros generate the special .type and .size directives which
 343    are used to set the corresponding fields of the linker symbol table
 344    entries in an ELF object file under SVR4.  These macros also output
 345    the starting labels for the relevant functions/objects.  */
 346
 347 /* Write the extra assembler code needed to declare an object properly.  */
 348
 349 #undef  ASM_DECLARE_OBJECT_NAME
 350 #define ASM_DECLARE_OBJECT_NAME(FILE, NAME, DECL)               \
 351   do {                                                          \
 352     HOST_WIDE_INT size;                                         \
 353     fprintf (FILE, "%s", TYPE_ASM_OP);                          \
 354     assemble_name (FILE, NAME);                                 \
 355     putc (',', FILE);                                           \
 356     fprintf (FILE, TYPE_OPERAND_FMT, "object");                 \
 357     putc ('\n', FILE);                                          \
 358     size_directive_output = 0;                                  \
 359     if (!flag_inhibit_size_directive                            \
 360         && DECL_SIZE (DECL)                                     \
 361         && (size = int_size_in_bytes (TREE_TYPE (DECL))) > 0)   \
 362       {                                                         \
 363         size_directive_output = 1;                              \
 364         fprintf (FILE, "%s", SIZE_ASM_OP);                      \
 365         assemble_name (FILE, NAME);                             \
 366         fputc (',', FILE);                                      \
 367         fprintf (FILE, HOST_WIDE_INT_PRINT_DEC, size);          \
 368         fputc ('\n', FILE);                                     \
 369       }                                                         \
 370     ASM_OUTPUT_LABEL(FILE, NAME);                               \
 371   } while (0)
 372
 373 /* Output the size directive for a decl in rest_of_decl_compilation
 374    in the case where we did not do so before the initializer.
 375    Once we find the error_mark_node, we know that the value of
 376    size_directive_output was set
 377    by ASM_DECLARE_OBJECT_NAME when it was run for the same decl.  */
 378
 379 #undef  ASM_FINISH_DECLARE_OBJECT
 380 #define ASM_FINISH_DECLARE_OBJECT(FILE, DECL, TOP_LEVEL, AT_END)        \
 381   do {                                                                  \
 382     const char *name = XSTR (XEXP (DECL_RTL (DECL), 0), 0);             \
 383     HOST_WIDE_INT size;                                                 \
 384     if (!flag_inhibit_size_directive                                    \
 385         && DECL_SIZE (DECL)                                             \
 386         && ! AT_END && TOP_LEVEL                                        \
 387         && DECL_INITIAL (DECL) == error_mark_node                       \
 388         && !size_directive_output                                       \
 389         && (size = int_size_in_bytes (TREE_TYPE (DECL))) > 0)           \
 390       {                                                                 \
 391         size_directive_output = 1;                                      \
 392         fprintf (FILE, "%s", SIZE_ASM_OP);                              \
 393         assemble_name (FILE, name);                                     \
 394         fputc (',', FILE);                                              \
 395         fprintf (FILE, HOST_WIDE_INT_PRINT_DEC, size);                  \
 396         fputc ('\n', FILE);                                             \
 397       }                                                                 \
 398   } while (0)
 399
 400 /* A table of bytes codes used by the ASM_OUTPUT_ASCII and
 401    ASM_OUTPUT_LIMITED_STRING macros.  Each byte in the table
 402    corresponds to a particular byte value [0..255].  For any
 403    given byte value, if the value in the corresponding table
 404    position is zero, the given character can be output directly.
 405    If the table value is 1, the byte must be output as a \ooo
 406    octal escape.  If the tables value is anything else, then the
 407    byte value should be output as a \ followed by the value
 408    in the table.  Note that we can use standard UN*X escape
 409    sequences for many control characters, but we don't use
 410    \a to represent BEL because some svr4 assemblers (e.g. on
 411    the i386) don't know about that.  Also, we don't use \v
 412    since some versions of gas, such as 2.2 did not accept it.  */
 413
 414 #undef  ESCAPES
 415 #define ESCAPES \
 416 "\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\
 417 \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\
 418 \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\
 419 \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\
 420 \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\
 421 \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\
 422 \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\
 423 \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"
 424
 425 /* Some svr4 assemblers have a limit on the number of characters which
 426    can appear in the operand of a .string directive.  If your assembler
 427    has such a limitation, you should define STRING_LIMIT to reflect that
 428    limit.  Note that at least some svr4 assemblers have a limit on the
 429    actual number of bytes in the double-quoted string, and that they
 430    count each character in an escape sequence as one byte.  Thus, an
 431    escape sequence like \377 would count as four bytes.
 432
 433    If your target assembler doesn't support the .string directive, you
 434    should define this to zero.  */
 435
 436 #undef  STRING_LIMIT
 437 #define STRING_LIMIT    ((unsigned) 256)
 438 #undef  STRING_ASM_OP
 439 #define STRING_ASM_OP   "\t.string\t"
 440
 441 /* GAS is the only Alpha/ELF assembler.  */
 442 #undef  TARGET_GAS
 443 #define TARGET_GAS      (1)
 444
 445 /* Provide a STARTFILE_SPEC appropriate for ELF.  Here we add the
 446    (even more) magical crtbegin.o file which provides part of the
 447    support for getting C++ file-scope static object constructed
 448    before entering `main'.   */
 449
 450 #undef  STARTFILE_SPEC
 451 #define STARTFILE_SPEC \
 452   "%{!shared: \
 453      %{pg:gcrt1.o%s} %{!pg:%{p:gcrt1.o%s} %{!p:crt1.o%s}}}\
 454    crti.o%s %{static:crtbeginT.o%s}\
 455    %{!static:%{shared:crtbeginS.o%s}%{!shared:crtbegin.o%s}}"
 456
 457 /* Provide a ENDFILE_SPEC appropriate for ELF.  Here we tack on the
 458    magical crtend.o file which provides part of the support for
 459    getting C++ file-scope static object constructed before entering
 460    `main', followed by a normal ELF "finalizer" file, `crtn.o'.  */
 461
 462 #undef  ENDFILE_SPEC
 463 #define ENDFILE_SPEC \
 464   "%{ffast-math|funsafe-math-optimizations:crtfastmath.o%s} \
 465    %{shared:crtendS.o%s}%{!shared:crtend.o%s} crtn.o%s"
 466
 467 /* We support #pragma.  */
 468 #define HANDLE_SYSV_PRAGMA
 469
 470 /* Select a format to encode pointers in exception handling data.  CODE
 471    is 0 for data, 1 for code labels, 2 for function pointers.  GLOBAL is
 472    true if the symbol may be affected by dynamic relocations.
 473
 474    Since application size is already constrained to <2GB by the form of
 475    the ldgp relocation, we can use a 32-bit pc-relative relocation to
 476    static data.  Dynamic data is accessed indirectly to allow for read
 477    only EH sections.  */
 478 #define ASM_PREFERRED_EH_DATA_FORMAT(CODE,GLOBAL)       \
 479   (((GLOBAL) ? DW_EH_PE_indirect : 0) | DW_EH_PE_pcrel | DW_EH_PE_sdata4)
 480
 481 /* If defined, a C statement to be executed just prior to the output of
 482    assembler code for INSN.  */
 483 #define FINAL_PRESCAN_INSN(INSN, OPVEC, NOPERANDS)      \
 484  (alpha_this_literal_sequence_number = 0,               \
 485   alpha_this_gpdisp_sequence_number = 0)
 486 extern int alpha_this_literal_sequence_number;
 487 extern int alpha_this_gpdisp_sequence_number;
 488
 489 /* Since the bits of the _init and _fini function is spread across
 490    many object files, each potentially with its own GP, we must assume
 491    we need to load our GP.  Further, the .init/.fini section can
 492    easily be more than 4MB away from the function to call so we can't
 493    use bsr.  */
 494 #define CRT_CALL_STATIC_FUNCTION(SECTION_OP, FUNC)      \
 495    asm (SECTION_OP "\n"                                 \
 496 "       br $29,1f\n"                                    \
 497 "1:     ldgp $29,0($29)\n"                              \
 498 "       unop\n"                                         \
 499 "       jsr $26," USER_LABEL_PREFIX #FUNC "\n"          \
 500 "       .align 3\n"                                     \
 501 "       .previous");
 502
 503 /* If we have the capability create headers for efficient EH lookup.
 504    As of Jan 2002, only glibc 2.2.4 can actually make use of this, but
 505    I imagine that other systems will catch up.  In the meantime, it
 506    doesn't harm to make sure that the data exists to be used later.  */
 507 #if defined(HAVE_LD_EH_FRAME_HDR)
 508 #define LINK_EH_SPEC "%{!static:--eh-frame-hdr} "
 509 #endif