gcc/config/elfos.h

   1 /* elfos.h  --  operating system specific defines to be used when
   2    targeting GCC for some generic ELF system
   3    Copyright (C) 1991, 1994, 1995, 1999, 2000, 2001, 2002, 2003
   4    Free Software Foundation, Inc.
   5    Based on svr4.h contributed by Ron Guilmette (rfg@netcom.com).
   6
   7 This file is part of GNU CC.
   8
   9 GNU CC is free software; you can redistribute it and/or modify
  10 it under the terms of the GNU General Public License as published by
  11 the Free Software Foundation; either version 2, or (at your option)
  12 any later version.
  13
  14 GNU CC is distributed in the hope that it will be useful,
  15 but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 GNU General Public License for more details.
  18
  19 You should have received a copy of the GNU General Public License
  20 along with GNU CC; see the file COPYING.  If not, write to
  21 the Free Software Foundation, 59 Temple Place - Suite 330,
  22 Boston, MA 02111-1307, USA.  */
  23
  24
  25 /* Define a symbol indicating that we are using elfos.h.
  26    Some CPU specific configuration files use this.  */
  27 #define USING_ELFOS_H
  28
  29 /* The prefix to add to user-visible assembler symbols.
  30
  31    For ELF systems the convention is *not* to prepend a leading
  32    underscore onto user-level symbol names.  */
  33
  34 #undef  USER_LABEL_PREFIX
  35 #define USER_LABEL_PREFIX ""
  36
  37 /* Biggest alignment supported by the object file format of this
  38    machine.  Use this macro to limit the alignment which can be
  39    specified using the `__attribute__ ((aligned (N)))' construct.  If
  40    not defined, the default value is `BIGGEST_ALIGNMENT'.  */
  41 #ifndef MAX_OFILE_ALIGNMENT
  42 #define MAX_OFILE_ALIGNMENT (32768 * 8)
  43 #endif
  44
  45 /* Use periods rather than dollar signs in special g++ assembler names.  */
  46
  47 #define NO_DOLLAR_IN_LABEL
  48
  49 /* Writing `int' for a bit-field forces int alignment for the structure.  */
  50
  51 #ifndef PCC_BITFIELD_TYPE_MATTERS
  52 #define PCC_BITFIELD_TYPE_MATTERS 1
  53 #endif
  54
  55 /* Implicit library calls should use memcpy, not bcopy, etc.  */
  56
  57 #define TARGET_MEM_FUNCTIONS
  58
  59 /* Handle #pragma weak and #pragma pack.  */
  60
  61 #define HANDLE_SYSV_PRAGMA 1
  62
  63 /* System V Release 4 uses DWARF debugging info.  */
  64
  65 #define DWARF_DEBUGGING_INFO 1
  66
  67 /* All ELF targets can support DWARF-2.  */
  68
  69 #define DWARF2_DEBUGGING_INFO 1
  70
  71 /* The GNU tools operate better with dwarf2, and it is required by some
  72    psABI's.  Since we don't have any native tools to be compatible with,
  73    default to dwarf2.  */
  74
  75 #ifndef PREFERRED_DEBUGGING_TYPE
  76 #define PREFERRED_DEBUGGING_TYPE DWARF2_DEBUG
  77 #endif
  78
  79 /* All SVR4 targets use the ELF object file format.  */
  80 #define OBJECT_FORMAT_ELF
  81
  82
  83 /* Output #ident as a .ident.  */
  84
  85 #define ASM_OUTPUT_IDENT(FILE, NAME) \
  86   fprintf (FILE, "%s\"%s\"\n", IDENT_ASM_OP, NAME);
  87
  88 #define IDENT_ASM_OP "\t.ident\t"
  89
  90 #undef  SET_ASM_OP
  91 #define SET_ASM_OP      "\t.set\t"
  92
  93 /* This is how to begin an assembly language file.  Most svr4 assemblers want
  94    at least a .file directive to come first, and some want to see a .version
  95    directive come right after that.  Here we just establish a default
  96    which generates only the .file directive.  If you need a .version
  97    directive for any specific target, you should override this definition
  98    in the target-specific file which includes this one.  */
  99
 100 #undef ASM_FILE_START
 101 #define ASM_FILE_START(FILE)                            \
 102   output_file_directive ((FILE), main_input_filename)
 103
 104 /* This is how to allocate empty space in some section.  The .zero
 105    pseudo-op is used for this on most svr4 assemblers.  */
 106
 107 #define SKIP_ASM_OP     "\t.zero\t"
 108
 109 #undef  ASM_OUTPUT_SKIP
 110 #define ASM_OUTPUT_SKIP(FILE, SIZE) \
 111   fprintf (FILE, "%s%u\n", SKIP_ASM_OP, (SIZE))
 112
 113 /* This is how to store into the string LABEL
 114    the symbol_ref name of an internal numbered label where
 115    PREFIX is the class of label and NUM is the number within the class.
 116    This is suitable for output with `assemble_name'.
 117
 118    For most svr4 systems, the convention is that any symbol which begins
 119    with a period is not put into the linker symbol table by the assembler.  */
 120
 121 #undef  ASM_GENERATE_INTERNAL_LABEL
 122 #define ASM_GENERATE_INTERNAL_LABEL(LABEL, PREFIX, NUM)         \
 123   do                                                            \
 124     {                                                           \
 125       sprintf (LABEL, "*.%s%u", PREFIX, (unsigned) (NUM));      \
 126     }                                                           \
 127   while (0)
 128
 129 /* Output the label which precedes a jumptable.  Note that for all svr4
 130    systems where we actually generate jumptables (which is to say every
 131    svr4 target except i386, where we use casesi instead) we put the jump-
 132    tables into the .rodata section and since other stuff could have been
 133    put into the .rodata section prior to any given jumptable, we have to
 134    make sure that the location counter for the .rodata section gets pro-
 135    perly re-aligned prior to the actual beginning of the jump table.  */
 136
 137 #undef ALIGN_ASM_OP
 138 #define ALIGN_ASM_OP "\t.align\t"
 139
 140 #ifndef ASM_OUTPUT_BEFORE_CASE_LABEL
 141 #define ASM_OUTPUT_BEFORE_CASE_LABEL(FILE, PREFIX, NUM, TABLE) \
 142   ASM_OUTPUT_ALIGN ((FILE), 2);
 143 #endif
 144
 145 #undef  ASM_OUTPUT_CASE_LABEL
 146 #define ASM_OUTPUT_CASE_LABEL(FILE, PREFIX, NUM, JUMPTABLE)             \
 147   do                                                                    \
 148     {                                                                   \
 149       ASM_OUTPUT_BEFORE_CASE_LABEL (FILE, PREFIX, NUM, JUMPTABLE)       \
 150         (*targetm.asm_out.internal_label) (FILE, PREFIX, NUM);                  \
 151     }                                                                   \
 152   while (0)
 153
 154 /* The standard SVR4 assembler seems to require that certain builtin
 155    library routines (e.g. .udiv) be explicitly declared as .globl
 156    in each assembly file where they are referenced.  */
 157
 158 #define ASM_OUTPUT_EXTERNAL_LIBCALL(FILE, FUN)  \
 159   (*targetm.asm_out.globalize_label) (FILE, XSTR (FUN, 0))
 160
 161 /* This says how to output assembler code to declare an
 162    uninitialized external linkage data object.  Under SVR4,
 163    the linker seems to want the alignment of data objects
 164    to depend on their types.  We do exactly that here.  */
 165
 166 #define COMMON_ASM_OP   "\t.comm\t"
 167
 168 #undef  ASM_OUTPUT_ALIGNED_COMMON
 169 #define ASM_OUTPUT_ALIGNED_COMMON(FILE, NAME, SIZE, ALIGN)              \
 170   do                                                                    \
 171     {                                                                   \
 172       fprintf ((FILE), "%s", COMMON_ASM_OP);                            \
 173       assemble_name ((FILE), (NAME));                                   \
 174       fprintf ((FILE), ",%u,%u\n", (SIZE), (ALIGN) / BITS_PER_UNIT);    \
 175     }                                                                   \
 176   while (0)
 177
 178 /* This says how to output assembler code to declare an
 179    uninitialized internal linkage data object.  Under SVR4,
 180    the linker seems to want the alignment of data objects
 181    to depend on their types.  We do exactly that here.  */
 182
 183 #define LOCAL_ASM_OP    "\t.local\t"
 184
 185 #undef  ASM_OUTPUT_ALIGNED_LOCAL
 186 #define ASM_OUTPUT_ALIGNED_LOCAL(FILE, NAME, SIZE, ALIGN)       \
 187   do                                                            \
 188     {                                                           \
 189       fprintf ((FILE), "%s", LOCAL_ASM_OP);                     \
 190       assemble_name ((FILE), (NAME));                           \
 191       fprintf ((FILE), "\n");                                   \
 192       ASM_OUTPUT_ALIGNED_COMMON (FILE, NAME, SIZE, ALIGN);      \
 193     }                                                           \
 194   while (0)
 195
 196 /* This is the pseudo-op used to generate a contiguous sequence of byte
 197    values from a double-quoted string WITHOUT HAVING A TERMINATING NUL
 198    AUTOMATICALLY APPENDED.  This is the same for most svr4 assemblers.  */
 199
 200 #undef  ASCII_DATA_ASM_OP
 201 #define ASCII_DATA_ASM_OP       "\t.ascii\t"
 202
 203 /* Support a read-only data section.  */
 204 #define READONLY_DATA_SECTION_ASM_OP    "\t.section\t.rodata"
 205
 206 /* On svr4, we *do* have support for the .init and .fini sections, and we
 207    can put stuff in there to be executed before and after `main'.  We let
 208    crtstuff.c and other files know this by defining the following symbols.
 209    The definitions say how to change sections to the .init and .fini
 210    sections.  This is the same for all known svr4 assemblers.  */
 211
 212 #define INIT_SECTION_ASM_OP     "\t.section\t.init"
 213 #define FINI_SECTION_ASM_OP     "\t.section\t.fini"
 214
 215 /* Output assembly directive to move to the beginning of current section.  */
 216 #ifdef HAVE_GAS_SUBSECTION_ORDERING
 217 # define ASM_SECTION_START_OP   "\t.subsection\t-1"
 218 # define ASM_OUTPUT_SECTION_START(FILE) \
 219   fprintf ((FILE), "%s\n", ASM_SECTION_START_OP)
 220 #endif
 221
 222 #define MAKE_DECL_ONE_ONLY(DECL) (DECL_WEAK (DECL) = 1)
 223
 224 /* Switch into a generic section.  */
 225 #define TARGET_ASM_NAMED_SECTION  default_elf_asm_named_section
 226
 227 #undef  TARGET_ASM_SELECT_RTX_SECTION
 228 #define TARGET_ASM_SELECT_RTX_SECTION default_elf_select_rtx_section
 229 #undef  TARGET_ASM_SELECT_SECTION
 230 #define TARGET_ASM_SELECT_SECTION default_elf_select_section
 231
 232 /* Define the strings used for the special svr4 .type and .size directives.
 233    These strings generally do not vary from one system running svr4 to
 234    another, but if a given system (e.g. m88k running svr) needs to use
 235    different pseudo-op names for these, they may be overridden in the
 236    file which includes this one.  */
 237
 238 #define TYPE_ASM_OP     "\t.type\t"
 239 #define SIZE_ASM_OP     "\t.size\t"
 240
 241 /* This is how we tell the assembler that a symbol is weak.  */
 242
 243 #define ASM_WEAKEN_LABEL(FILE, NAME)    \
 244   do                                    \
 245     {                                   \
 246       fputs ("\t.weak\t", (FILE));      \
 247       assemble_name ((FILE), (NAME));   \
 248       fputc ('\n', (FILE));             \
 249     }                                   \
 250   while (0)
 251
 252 /* The following macro defines the format used to output the second
 253    operand of the .type assembler directive.  Different svr4 assemblers
 254    expect various different forms for this operand.  The one given here
 255    is just a default.  You may need to override it in your machine-
 256    specific tm.h file (depending upon the particulars of your assembler).  */
 257
 258 #define TYPE_OPERAND_FMT        "@%s"
 259
 260 /* Write the extra assembler code needed to declare a function's result.
 261    Most svr4 assemblers don't require any special declaration of the
 262    result value, but there are exceptions.  */
 263
 264 #ifndef ASM_DECLARE_RESULT
 265 #define ASM_DECLARE_RESULT(FILE, RESULT)
 266 #endif
 267
 268 /* These macros generate the special .type and .size directives which
 269    are used to set the corresponding fields of the linker symbol table
 270    entries in an ELF object file under SVR4.  These macros also output
 271    the starting labels for the relevant functions/objects.  */
 272
 273 /* Write the extra assembler code needed to declare a function properly.
 274    Some svr4 assemblers need to also have something extra said about the
 275    function's return value.  We allow for that here.  */
 276
 277 #ifndef ASM_DECLARE_FUNCTION_NAME
 278 #define ASM_DECLARE_FUNCTION_NAME(FILE, NAME, DECL)             \
 279   do                                                            \
 280     {                                                           \
 281       ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "function");       \
 282       ASM_DECLARE_RESULT (FILE, DECL_RESULT (DECL));            \
 283       ASM_OUTPUT_LABEL (FILE, NAME);                            \
 284     }                                                           \
 285   while (0)
 286 #endif
 287
 288 /* Write the extra assembler code needed to declare an object properly.  */
 289
 290 #define ASM_DECLARE_OBJECT_NAME(FILE, NAME, DECL)               \
 291   do                                                            \
 292     {                                                           \
 293       HOST_WIDE_INT size;                                       \
 294                                                                 \
 295       ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "object");         \
 296                                                                 \
 297       size_directive_output = 0;                                \
 298       if (!flag_inhibit_size_directive                          \
 299           && (DECL) && DECL_SIZE (DECL))                        \
 300         {                                                       \
 301           size_directive_output = 1;                            \
 302           size = int_size_in_bytes (TREE_TYPE (DECL));          \
 303           ASM_OUTPUT_SIZE_DIRECTIVE (FILE, NAME, size);         \
 304         }                                                       \
 305                                                                 \
 306       ASM_OUTPUT_LABEL (FILE, NAME);                            \
 307     }                                                           \
 308   while (0)
 309
 310 /* Output the size directive for a decl in rest_of_decl_compilation
 311    in the case where we did not do so before the initializer.
 312    Once we find the error_mark_node, we know that the value of
 313    size_directive_output was set
 314    by ASM_DECLARE_OBJECT_NAME when it was run for the same decl.  */
 315
 316 #undef ASM_FINISH_DECLARE_OBJECT
 317 #define ASM_FINISH_DECLARE_OBJECT(FILE, DECL, TOP_LEVEL, AT_END)\
 318   do                                                            \
 319     {                                                           \
 320       const char *name = XSTR (XEXP (DECL_RTL (DECL), 0), 0);   \
 321       HOST_WIDE_INT size;                                       \
 322                                                                 \
 323       if (!flag_inhibit_size_directive                          \
 324           && DECL_SIZE (DECL)                                   \
 325           && ! AT_END && TOP_LEVEL                              \
 326           && DECL_INITIAL (DECL) == error_mark_node             \
 327           && !size_directive_output)                            \
 328         {                                                       \
 329           size_directive_output = 1;                            \
 330           size = int_size_in_bytes (TREE_TYPE (DECL));          \
 331           ASM_OUTPUT_SIZE_DIRECTIVE (FILE, name, size);         \
 332         }                                                       \
 333     }                                                           \
 334   while (0)
 335
 336 /* This is how to declare the size of a function.  */
 337 #ifndef ASM_DECLARE_FUNCTION_SIZE
 338 #define ASM_DECLARE_FUNCTION_SIZE(FILE, FNAME, DECL)            \
 339   do                                                            \
 340     {                                                           \
 341       if (!flag_inhibit_size_directive)                         \
 342         ASM_OUTPUT_MEASURED_SIZE (FILE, FNAME);                 \
 343     }                                                           \
 344   while (0)
 345 #endif
 346
 347 /* A table of bytes codes used by the ASM_OUTPUT_ASCII and
 348    ASM_OUTPUT_LIMITED_STRING macros.  Each byte in the table
 349    corresponds to a particular byte value [0..255].  For any
 350    given byte value, if the value in the corresponding table
 351    position is zero, the given character can be output directly.
 352    If the table value is 1, the byte must be output as a \ooo
 353    octal escape.  If the tables value is anything else, then the
 354    byte value should be output as a \ followed by the value
 355    in the table.  Note that we can use standard UN*X escape
 356    sequences for many control characters, but we don't use
 357    \a to represent BEL because some svr4 assemblers (e.g. on
 358    the i386) don't know about that.  Also, we don't use \v
 359    since some versions of gas, such as 2.2 did not accept it.  */
 360
 361 #define ESCAPES \
 362 "\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\
 363 \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\
 364 \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\
 365 \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\
 366 \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\
 367 \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\
 368 \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\
 369 \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"
 370
 371 /* Some svr4 assemblers have a limit on the number of characters which
 372    can appear in the operand of a .string directive.  If your assembler
 373    has such a limitation, you should define STRING_LIMIT to reflect that
 374    limit.  Note that at least some svr4 assemblers have a limit on the
 375    actual number of bytes in the double-quoted string, and that they
 376    count each character in an escape sequence as one byte.  Thus, an
 377    escape sequence like \377 would count as four bytes.
 378
 379    If your target assembler doesn't support the .string directive, you
 380    should define this to zero.
 381 */
 382
 383 #define STRING_LIMIT    ((unsigned) 256)
 384
 385 #define STRING_ASM_OP   "\t.string\t"
 386
 387 /* The routine used to output NUL terminated strings.  We use a special
 388    version of this for most svr4 targets because doing so makes the
 389    generated assembly code more compact (and thus faster to assemble)
 390    as well as more readable, especially for targets like the i386
 391    (where the only alternative is to output character sequences as
 392    comma separated lists of numbers).  */
 393
 394 #define ASM_OUTPUT_LIMITED_STRING(FILE, STR)            \
 395   do                                                    \
 396     {                                                   \
 397       register const unsigned char *_limited_str =      \
 398         (const unsigned char *) (STR);                  \
 399       register unsigned ch;                             \
 400                                                         \
 401       fprintf ((FILE), "%s\"", STRING_ASM_OP);          \
 402                                                         \
 403       for (; (ch = *_limited_str); _limited_str++)      \
 404         {                                               \
 405           register int escape;                          \
 406                                                         \
 407           switch (escape = ESCAPES[ch])                 \
 408             {                                           \
 409             case 0:                                     \
 410               putc (ch, (FILE));                        \
 411               break;                                    \
 412             case 1:                                     \
 413               fprintf ((FILE), "\\%03o", ch);           \
 414               break;                                    \
 415             default:                                    \
 416               putc ('\\', (FILE));                      \
 417               putc (escape, (FILE));                    \
 418               break;                                    \
 419             }                                           \
 420         }                                               \
 421                                                         \
 422       fprintf ((FILE), "\"\n");                         \
 423     }                                                   \
 424   while (0)
 425
 426 /* The routine used to output sequences of byte values.  We use a special
 427    version of this for most svr4 targets because doing so makes the
 428    generated assembly code more compact (and thus faster to assemble)
 429    as well as more readable.  Note that if we find subparts of the
 430    character sequence which end with NUL (and which are shorter than
 431    STRING_LIMIT) we output those using ASM_OUTPUT_LIMITED_STRING.  */
 432
 433 #undef  ASM_OUTPUT_ASCII
 434 #define ASM_OUTPUT_ASCII(FILE, STR, LENGTH)                             \
 435   do                                                                    \
 436     {                                                                   \
 437       register const unsigned char *_ascii_bytes =                      \
 438         (const unsigned char *) (STR);                                  \
 439       register const unsigned char *limit = _ascii_bytes + (LENGTH);    \
 440       register unsigned bytes_in_chunk = 0;                             \
 441                                                                         \
 442       for (; _ascii_bytes < limit; _ascii_bytes++)                      \
 443         {                                                               \
 444           register const unsigned char *p;                              \
 445                                                                         \
 446           if (bytes_in_chunk >= 60)                                     \
 447             {                                                           \
 448               fprintf ((FILE), "\"\n");                                 \
 449               bytes_in_chunk = 0;                                       \
 450             }                                                           \
 451                                                                         \
 452           for (p = _ascii_bytes; p < limit && *p != '\0'; p++)          \
 453             continue;                                                   \
 454                                                                         \
 455           if (p < limit && (p - _ascii_bytes) <= (long)STRING_LIMIT)    \
 456             {                                                           \
 457               if (bytes_in_chunk > 0)                                   \
 458                 {                                                       \
 459                   fprintf ((FILE), "\"\n");                             \
 460                   bytes_in_chunk = 0;                                   \
 461                 }                                                       \
 462                                                                         \
 463               ASM_OUTPUT_LIMITED_STRING ((FILE), _ascii_bytes);         \
 464               _ascii_bytes = p;                                         \
 465             }                                                           \
 466           else                                                          \
 467             {                                                           \
 468               register int escape;                                      \
 469               register unsigned ch;                                     \
 470                                                                         \
 471               if (bytes_in_chunk == 0)                                  \
 472                 fprintf ((FILE), "%s\"", ASCII_DATA_ASM_OP);            \
 473                                                                         \
 474               switch (escape = ESCAPES[ch = *_ascii_bytes])             \
 475                 {                                                       \
 476                 case 0:                                                 \
 477                   putc (ch, (FILE));                                    \
 478                   bytes_in_chunk++;                                     \
 479                   break;                                                \
 480                 case 1:                                                 \
 481                   fprintf ((FILE), "\\%03o", ch);                       \
 482                   bytes_in_chunk += 4;                                  \
 483                   break;                                                \
 484                 default:                                                \
 485                   putc ('\\', (FILE));                                  \
 486                   putc (escape, (FILE));                                \
 487                   bytes_in_chunk += 2;                                  \
 488                   break;                                                \
 489                 }                                                       \
 490             }                                                           \
 491         }                                                               \
 492                                                                         \
 493       if (bytes_in_chunk > 0)                                           \
 494         fprintf ((FILE), "\"\n");                                       \
 495     }                                                                   \
 496   while (0)