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, 2004
   4    Free Software Foundation, Inc.
   5    Based on svr4.h contributed by Ron Guilmette (rfg@netcom.com).
   6
   7 This file is part of GCC.
   8
   9 GCC 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 GCC 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 GCC; see the file COPYING.  If not, write to
  21 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
  22 Boston, MA 02110-1301, USA.  */
  23
  24 #define TARGET_OBJFMT_CPP_BUILTINS()            \
  25   do                                            \
  26     {                                           \
  27         builtin_define ("__ELF__");             \
  28     }                                           \
  29   while (0)
  30
  31 /* Define a symbol indicating that we are using elfos.h.
  32    Some CPU specific configuration files use this.  */
  33 #define USING_ELFOS_H
  34
  35 /* The prefix to add to user-visible assembler symbols.
  36
  37    For ELF systems the convention is *not* to prepend a leading
  38    underscore onto user-level symbol names.  */
  39
  40 #undef  USER_LABEL_PREFIX
  41 #define USER_LABEL_PREFIX ""
  42
  43 /* Biggest alignment supported by the object file format of this
  44    machine.  Use this macro to limit the alignment which can be
  45    specified using the `__attribute__ ((aligned (N)))' construct.  If
  46    not defined, the default value is `BIGGEST_ALIGNMENT'.  */
  47 #ifndef MAX_OFILE_ALIGNMENT
  48 #define MAX_OFILE_ALIGNMENT (32768 * 8)
  49 #endif
  50
  51 /* Use periods rather than dollar signs in special g++ assembler names.  */
  52
  53 #define NO_DOLLAR_IN_LABEL
  54
  55 /* Writing `int' for a bit-field forces int alignment for the structure.  */
  56
  57 #ifndef PCC_BITFIELD_TYPE_MATTERS
  58 #define PCC_BITFIELD_TYPE_MATTERS 1
  59 #endif
  60
  61 /* Handle #pragma weak and #pragma pack.  */
  62
  63 #define HANDLE_SYSV_PRAGMA 1
  64
  65 /* All ELF targets can support DWARF-2.  */
  66
  67 #define DWARF2_DEBUGGING_INFO 1
  68
  69 /* The GNU tools operate better with dwarf2, and it is required by some
  70    psABI's.  Since we don't have any native tools to be compatible with,
  71    default to dwarf2.  */
  72
  73 #ifndef PREFERRED_DEBUGGING_TYPE
  74 #define PREFERRED_DEBUGGING_TYPE DWARF2_DEBUG
  75 #endif
  76
  77 /* All SVR4 targets use the ELF object file format.  */
  78 #define OBJECT_FORMAT_ELF
  79
  80
  81 /* Output #ident as a .ident.  */
  82
  83 #define ASM_OUTPUT_IDENT(FILE, NAME) \
  84   fprintf (FILE, "%s\"%s\"\n", IDENT_ASM_OP, NAME);
  85
  86 #define IDENT_ASM_OP "\t.ident\t"
  87
  88 #undef  SET_ASM_OP
  89 #define SET_ASM_OP      "\t.set\t"
  90
  91 /* Most svr4 assemblers want a .file directive at the beginning of
  92    their input file.  */
  93 #define TARGET_ASM_FILE_START_FILE_DIRECTIVE true
  94
  95 /* This is how to allocate empty space in some section.  The .zero
  96    pseudo-op is used for this on most svr4 assemblers.  */
  97
  98 #define SKIP_ASM_OP     "\t.zero\t"
  99
 100 #undef  ASM_OUTPUT_SKIP
 101 #define ASM_OUTPUT_SKIP(FILE, SIZE) \
 102    fprintf ((FILE), "%s"HOST_WIDE_INT_PRINT_UNSIGNED"\n",\
 103             SKIP_ASM_OP, (SIZE))
 104
 105 /* This is how to store into the string LABEL
 106    the symbol_ref name of an internal numbered label where
 107    PREFIX is the class of label and NUM is the number within the class.
 108    This is suitable for output with `assemble_name'.
 109
 110    For most svr4 systems, the convention is that any symbol which begins
 111    with a period is not put into the linker symbol table by the assembler.  */
 112
 113 #undef  ASM_GENERATE_INTERNAL_LABEL
 114 #define ASM_GENERATE_INTERNAL_LABEL(LABEL, PREFIX, NUM)         \
 115   do                                                            \
 116     {                                                           \
 117       sprintf (LABEL, "*.%s%u", PREFIX, (unsigned) (NUM));      \
 118     }                                                           \
 119   while (0)
 120
 121 /* Output the label which precedes a jumptable.  Note that for all svr4
 122    systems where we actually generate jumptables (which is to say every
 123    svr4 target except i386, where we use casesi instead) we put the jump-
 124    tables into the .rodata section and since other stuff could have been
 125    put into the .rodata section prior to any given jumptable, we have to
 126    make sure that the location counter for the .rodata section gets pro-
 127    perly re-aligned prior to the actual beginning of the jump table.  */
 128
 129 #undef ALIGN_ASM_OP
 130 #define ALIGN_ASM_OP "\t.align\t"
 131
 132 #ifndef ASM_OUTPUT_BEFORE_CASE_LABEL
 133 #define ASM_OUTPUT_BEFORE_CASE_LABEL(FILE, PREFIX, NUM, TABLE) \
 134   ASM_OUTPUT_ALIGN ((FILE), 2);
 135 #endif
 136
 137 #undef  ASM_OUTPUT_CASE_LABEL
 138 #define ASM_OUTPUT_CASE_LABEL(FILE, PREFIX, NUM, JUMPTABLE)             \
 139   do                                                                    \
 140     {                                                                   \
 141       ASM_OUTPUT_BEFORE_CASE_LABEL (FILE, PREFIX, NUM, JUMPTABLE)       \
 142         (*targetm.asm_out.internal_label) (FILE, PREFIX, NUM);                  \
 143     }                                                                   \
 144   while (0)
 145
 146 /* The standard SVR4 assembler seems to require that certain builtin
 147    library routines (e.g. .udiv) be explicitly declared as .globl
 148    in each assembly file where they are referenced.  */
 149
 150 #define ASM_OUTPUT_EXTERNAL_LIBCALL(FILE, FUN)  \
 151   (*targetm.asm_out.globalize_label) (FILE, XSTR (FUN, 0))
 152
 153 /* This says how to output assembler code to declare an
 154    uninitialized external linkage data object.  Under SVR4,
 155    the linker seems to want the alignment of data objects
 156    to depend on their types.  We do exactly that here.  */
 157
 158 #define COMMON_ASM_OP   "\t.comm\t"
 159
 160 #undef  ASM_OUTPUT_ALIGNED_COMMON
 161 #define ASM_OUTPUT_ALIGNED_COMMON(FILE, NAME, SIZE, ALIGN)              \
 162   do                                                                    \
 163     {                                                                   \
 164       fprintf ((FILE), "%s", COMMON_ASM_OP);                            \
 165       assemble_name ((FILE), (NAME));                                   \
 166       fprintf ((FILE), ","HOST_WIDE_INT_PRINT_UNSIGNED",%u\n",          \
 167                (SIZE), (ALIGN) / BITS_PER_UNIT);                        \
 168     }                                                                   \
 169   while (0)
 170
 171 /* This says how to output assembler code to declare an
 172    uninitialized internal linkage data object.  Under SVR4,
 173    the linker seems to want the alignment of data objects
 174    to depend on their types.  We do exactly that here.  */
 175
 176 #define LOCAL_ASM_OP    "\t.local\t"
 177
 178 #undef  ASM_OUTPUT_ALIGNED_LOCAL
 179 #define ASM_OUTPUT_ALIGNED_LOCAL(FILE, NAME, SIZE, ALIGN)       \
 180   do                                                            \
 181     {                                                           \
 182       fprintf ((FILE), "%s", LOCAL_ASM_OP);                     \
 183       assemble_name ((FILE), (NAME));                           \
 184       fprintf ((FILE), "\n");                                   \
 185       ASM_OUTPUT_ALIGNED_COMMON (FILE, NAME, SIZE, ALIGN);      \
 186     }                                                           \
 187   while (0)
 188
 189 /* This is the pseudo-op used to generate a contiguous sequence of byte
 190    values from a double-quoted string WITHOUT HAVING A TERMINATING NUL
 191    AUTOMATICALLY APPENDED.  This is the same for most svr4 assemblers.  */
 192
 193 #undef  ASCII_DATA_ASM_OP
 194 #define ASCII_DATA_ASM_OP       "\t.ascii\t"
 195
 196 /* Support a read-only data section.  */
 197 #define READONLY_DATA_SECTION_ASM_OP    "\t.section\t.rodata"
 198
 199 /* On svr4, we *do* have support for the .init and .fini sections, and we
 200    can put stuff in there to be executed before and after `main'.  We let
 201    crtstuff.c and other files know this by defining the following symbols.
 202    The definitions say how to change sections to the .init and .fini
 203    sections.  This is the same for all known svr4 assemblers.  */
 204
 205 #define INIT_SECTION_ASM_OP     "\t.section\t.init"
 206 #define FINI_SECTION_ASM_OP     "\t.section\t.fini"
 207
 208 /* Output assembly directive to move to the beginning of current section.  */
 209 #ifdef HAVE_GAS_SUBSECTION_ORDERING
 210 # define ASM_SECTION_START_OP   "\t.subsection\t-1"
 211 # define ASM_OUTPUT_SECTION_START(FILE) \
 212   fprintf ((FILE), "%s\n", ASM_SECTION_START_OP)
 213 #endif
 214
 215 #define MAKE_DECL_ONE_ONLY(DECL) (DECL_WEAK (DECL) = 1)
 216
 217 /* Switch into a generic section.  */
 218 #define TARGET_ASM_NAMED_SECTION  default_elf_asm_named_section
 219
 220 #undef  TARGET_ASM_SELECT_RTX_SECTION
 221 #define TARGET_ASM_SELECT_RTX_SECTION default_elf_select_rtx_section
 222 #undef  TARGET_ASM_SELECT_SECTION
 223 #define TARGET_ASM_SELECT_SECTION default_elf_select_section
 224 #undef  TARGET_HAVE_SWITCHABLE_BSS_SECTIONS
 225 #define TARGET_HAVE_SWITCHABLE_BSS_SECTIONS true
 226
 227 /* Define the strings used for the special svr4 .type and .size directives.
 228    These strings generally do not vary from one system running svr4 to
 229    another, but if a given system (e.g. m88k running svr) needs to use
 230    different pseudo-op names for these, they may be overridden in the
 231    file which includes this one.  */
 232
 233 #define TYPE_ASM_OP     "\t.type\t"
 234 #define SIZE_ASM_OP     "\t.size\t"
 235
 236 /* This is how we tell the assembler that a symbol is weak.  */
 237
 238 #define ASM_WEAKEN_LABEL(FILE, NAME)    \
 239   do                                    \
 240     {                                   \
 241       fputs ("\t.weak\t", (FILE));      \
 242       assemble_name ((FILE), (NAME));   \
 243       fputc ('\n', (FILE));             \
 244     }                                   \
 245   while (0)
 246
 247 /* The following macro defines the format used to output the second
 248    operand of the .type assembler directive.  Different svr4 assemblers
 249    expect various different forms for this operand.  The one given here
 250    is just a default.  You may need to override it in your machine-
 251    specific tm.h file (depending upon the particulars of your assembler).  */
 252
 253 #define TYPE_OPERAND_FMT        "@%s"
 254
 255 /* Write the extra assembler code needed to declare a function's result.
 256    Most svr4 assemblers don't require any special declaration of the
 257    result value, but there are exceptions.  */
 258
 259 #ifndef ASM_DECLARE_RESULT
 260 #define ASM_DECLARE_RESULT(FILE, RESULT)
 261 #endif
 262
 263 /* These macros generate the special .type and .size directives which
 264    are used to set the corresponding fields of the linker symbol table
 265    entries in an ELF object file under SVR4.  These macros also output
 266    the starting labels for the relevant functions/objects.  */
 267
 268 /* Write the extra assembler code needed to declare a function properly.
 269    Some svr4 assemblers need to also have something extra said about the
 270    function's return value.  We allow for that here.  */
 271
 272 #ifndef ASM_DECLARE_FUNCTION_NAME
 273 #define ASM_DECLARE_FUNCTION_NAME(FILE, NAME, DECL)             \
 274   do                                                            \
 275     {                                                           \
 276       ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "function");       \
 277       ASM_DECLARE_RESULT (FILE, DECL_RESULT (DECL));            \
 278       ASM_OUTPUT_LABEL (FILE, NAME);                            \
 279     }                                                           \
 280   while (0)
 281 #endif
 282
 283 /* Write the extra assembler code needed to declare an object properly.  */
 284
 285 #define ASM_DECLARE_OBJECT_NAME(FILE, NAME, DECL)               \
 286   do                                                            \
 287     {                                                           \
 288       HOST_WIDE_INT size;                                       \
 289                                                                 \
 290       ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "object");         \
 291                                                                 \
 292       size_directive_output = 0;                                \
 293       if (!flag_inhibit_size_directive                          \
 294           && (DECL) && DECL_SIZE (DECL))                        \
 295         {                                                       \
 296           size_directive_output = 1;                            \
 297           size = int_size_in_bytes (TREE_TYPE (DECL));          \
 298           ASM_OUTPUT_SIZE_DIRECTIVE (FILE, NAME, size);         \
 299         }                                                       \
 300                                                                 \
 301       ASM_OUTPUT_LABEL (FILE, NAME);                            \
 302     }                                                           \
 303   while (0)
 304
 305 /* Output the size directive for a decl in rest_of_decl_compilation
 306    in the case where we did not do so before the initializer.
 307    Once we find the error_mark_node, we know that the value of
 308    size_directive_output was set
 309    by ASM_DECLARE_OBJECT_NAME when it was run for the same decl.  */
 310
 311 #undef ASM_FINISH_DECLARE_OBJECT
 312 #define ASM_FINISH_DECLARE_OBJECT(FILE, DECL, TOP_LEVEL, AT_END)\
 313   do                                                            \
 314     {                                                           \
 315       const char *name = XSTR (XEXP (DECL_RTL (DECL), 0), 0);   \
 316       HOST_WIDE_INT size;                                       \
 317                                                                 \
 318       if (!flag_inhibit_size_directive                          \
 319           && DECL_SIZE (DECL)                                   \
 320           && ! AT_END && TOP_LEVEL                              \
 321           && DECL_INITIAL (DECL) == error_mark_node             \
 322           && !size_directive_output)                            \
 323         {                                                       \
 324           size_directive_output = 1;                            \
 325           size = int_size_in_bytes (TREE_TYPE (DECL));          \
 326           ASM_OUTPUT_SIZE_DIRECTIVE (FILE, name, size);         \
 327         }                                                       \
 328     }                                                           \
 329   while (0)
 330
 331 /* This is how to declare the size of a function.  */
 332 #ifndef ASM_DECLARE_FUNCTION_SIZE
 333 #define ASM_DECLARE_FUNCTION_SIZE(FILE, FNAME, DECL)            \
 334   do                                                            \
 335     {                                                           \
 336       if (!flag_inhibit_size_directive)                         \
 337         ASM_OUTPUT_MEASURED_SIZE (FILE, FNAME);                 \
 338     }                                                           \
 339   while (0)
 340 #endif
 341
 342 /* A table of bytes codes used by the ASM_OUTPUT_ASCII and
 343    ASM_OUTPUT_LIMITED_STRING macros.  Each byte in the table
 344    corresponds to a particular byte value [0..255].  For any
 345    given byte value, if the value in the corresponding table
 346    position is zero, the given character can be output directly.
 347    If the table value is 1, the byte must be output as a \ooo
 348    octal escape.  If the tables value is anything else, then the
 349    byte value should be output as a \ followed by the value
 350    in the table.  Note that we can use standard UN*X escape
 351    sequences for many control characters, but we don't use
 352    \a to represent BEL because some svr4 assemblers (e.g. on
 353    the i386) don't know about that.  Also, we don't use \v
 354    since some versions of gas, such as 2.2 did not accept it.  */
 355
 356 #define ESCAPES \
 357 "\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\
 358 \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\
 359 \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\
 360 \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\
 361 \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\
 362 \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\
 363 \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\
 364 \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"
 365
 366 /* Some svr4 assemblers have a limit on the number of characters which
 367    can appear in the operand of a .string directive.  If your assembler
 368    has such a limitation, you should define STRING_LIMIT to reflect that
 369    limit.  Note that at least some svr4 assemblers have a limit on the
 370    actual number of bytes in the double-quoted string, and that they
 371    count each character in an escape sequence as one byte.  Thus, an
 372    escape sequence like \377 would count as four bytes.
 373
 374    If your target assembler doesn't support the .string directive, you
 375    should define this to zero.
 376 */
 377
 378 #define STRING_LIMIT    ((unsigned) 256)
 379
 380 #define STRING_ASM_OP   "\t.string\t"
 381
 382 /* The routine used to output NUL terminated strings.  We use a special
 383    version of this for most svr4 targets because doing so makes the
 384    generated assembly code more compact (and thus faster to assemble)
 385    as well as more readable, especially for targets like the i386
 386    (where the only alternative is to output character sequences as
 387    comma separated lists of numbers).  */
 388
 389 #define ASM_OUTPUT_LIMITED_STRING(FILE, STR)            \
 390   do                                                    \
 391     {                                                   \
 392       register const unsigned char *_limited_str =      \
 393         (const unsigned char *) (STR);                  \
 394       register unsigned ch;                             \
 395                                                         \
 396       fprintf ((FILE), "%s\"", STRING_ASM_OP);          \
 397                                                         \
 398       for (; (ch = *_limited_str); _limited_str++)      \
 399         {                                               \
 400           register int escape;                          \
 401                                                         \
 402           switch (escape = ESCAPES[ch])                 \
 403             {                                           \
 404             case 0:                                     \
 405               putc (ch, (FILE));                        \
 406               break;                                    \
 407             case 1:                                     \
 408               fprintf ((FILE), "\\%03o", ch);           \
 409               break;                                    \
 410             default:                                    \
 411               putc ('\\', (FILE));                      \
 412               putc (escape, (FILE));                    \
 413               break;                                    \
 414             }                                           \
 415         }                                               \
 416                                                         \
 417       fprintf ((FILE), "\"\n");                         \
 418     }                                                   \
 419   while (0)
 420
 421 /* The routine used to output sequences of byte values.  We use a special
 422    version of this for most svr4 targets because doing so makes the
 423    generated assembly code more compact (and thus faster to assemble)
 424    as well as more readable.  Note that if we find subparts of the
 425    character sequence which end with NUL (and which are shorter than
 426    STRING_LIMIT) we output those using ASM_OUTPUT_LIMITED_STRING.  */
 427
 428 #undef  ASM_OUTPUT_ASCII
 429 #define ASM_OUTPUT_ASCII(FILE, STR, LENGTH)                             \
 430   do                                                                    \
 431     {                                                                   \
 432       register const unsigned char *_ascii_bytes =                      \
 433         (const unsigned char *) (STR);                                  \
 434       register const unsigned char *limit = _ascii_bytes + (LENGTH);    \
 435       register unsigned bytes_in_chunk = 0;                             \
 436                                                                         \
 437       for (; _ascii_bytes < limit; _ascii_bytes++)                      \
 438         {                                                               \
 439           register const unsigned char *p;                              \
 440                                                                         \
 441           if (bytes_in_chunk >= 60)                                     \
 442             {                                                           \
 443               fprintf ((FILE), "\"\n");                                 \
 444               bytes_in_chunk = 0;                                       \
 445             }                                                           \
 446                                                                         \
 447           for (p = _ascii_bytes; p < limit && *p != '\0'; p++)          \
 448             continue;                                                   \
 449                                                                         \
 450           if (p < limit && (p - _ascii_bytes) <= (long)STRING_LIMIT)    \
 451             {                                                           \
 452               if (bytes_in_chunk > 0)                                   \
 453                 {                                                       \
 454                   fprintf ((FILE), "\"\n");                             \
 455                   bytes_in_chunk = 0;                                   \
 456                 }                                                       \
 457                                                                         \
 458               ASM_OUTPUT_LIMITED_STRING ((FILE), _ascii_bytes);         \
 459               _ascii_bytes = p;                                         \
 460             }                                                           \
 461           else                                                          \
 462             {                                                           \
 463               register int escape;                                      \
 464               register unsigned ch;                                     \
 465                                                                         \
 466               if (bytes_in_chunk == 0)                                  \
 467                 fprintf ((FILE), "%s\"", ASCII_DATA_ASM_OP);            \
 468                                                                         \
 469               switch (escape = ESCAPES[ch = *_ascii_bytes])             \
 470                 {                                                       \
 471                 case 0:                                                 \
 472                   putc (ch, (FILE));                                    \
 473                   bytes_in_chunk++;                                     \
 474                   break;                                                \
 475                 case 1:                                                 \
 476                   fprintf ((FILE), "\\%03o", ch);                       \
 477                   bytes_in_chunk += 4;                                  \
 478                   break;                                                \
 479                 default:                                                \
 480                   putc ('\\', (FILE));                                  \
 481                   putc (escape, (FILE));                                \
 482                   bytes_in_chunk += 2;                                  \
 483                   break;                                                \
 484                 }                                                       \
 485             }                                                           \
 486         }                                                               \
 487                                                                         \
 488       if (bytes_in_chunk > 0)                                           \
 489         fprintf ((FILE), "\"\n");                                       \
 490     }                                                                   \
 491   while (0)