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"HOST_WIDE_INT_PRINT_UNSIGNED"\n",\
 112             SKIP_ASM_OP, (SIZE))
 113
 114 /* This is how to store into the string LABEL
 115    the symbol_ref name of an internal numbered label where
 116    PREFIX is the class of label and NUM is the number within the class.
 117    This is suitable for output with `assemble_name'.
 118
 119    For most svr4 systems, the convention is that any symbol which begins
 120    with a period is not put into the linker symbol table by the assembler.  */
 121
 122 #undef  ASM_GENERATE_INTERNAL_LABEL
 123 #define ASM_GENERATE_INTERNAL_LABEL(LABEL, PREFIX, NUM)         \
 124   do                                                            \
 125     {                                                           \
 126       sprintf (LABEL, "*.%s%u", PREFIX, (unsigned) (NUM));      \
 127     }                                                           \
 128   while (0)
 129
 130 /* Output the label which precedes a jumptable.  Note that for all svr4
 131    systems where we actually generate jumptables (which is to say every
 132    svr4 target except i386, where we use casesi instead) we put the jump-
 133    tables into the .rodata section and since other stuff could have been
 134    put into the .rodata section prior to any given jumptable, we have to
 135    make sure that the location counter for the .rodata section gets pro-
 136    perly re-aligned prior to the actual beginning of the jump table.  */
 137
 138 #undef ALIGN_ASM_OP
 139 #define ALIGN_ASM_OP "\t.align\t"
 140
 141 #ifndef ASM_OUTPUT_BEFORE_CASE_LABEL
 142 #define ASM_OUTPUT_BEFORE_CASE_LABEL(FILE, PREFIX, NUM, TABLE) \
 143   ASM_OUTPUT_ALIGN ((FILE), 2);
 144 #endif
 145
 146 #undef  ASM_OUTPUT_CASE_LABEL
 147 #define ASM_OUTPUT_CASE_LABEL(FILE, PREFIX, NUM, JUMPTABLE)             \
 148   do                                                                    \
 149     {                                                                   \
 150       ASM_OUTPUT_BEFORE_CASE_LABEL (FILE, PREFIX, NUM, JUMPTABLE)       \
 151         (*targetm.asm_out.internal_label) (FILE, PREFIX, NUM);                  \
 152     }                                                                   \
 153   while (0)
 154
 155 /* The standard SVR4 assembler seems to require that certain builtin
 156    library routines (e.g. .udiv) be explicitly declared as .globl
 157    in each assembly file where they are referenced.  */
 158
 159 #define ASM_OUTPUT_EXTERNAL_LIBCALL(FILE, FUN)  \
 160   (*targetm.asm_out.globalize_label) (FILE, XSTR (FUN, 0))
 161
 162 /* This says how to output assembler code to declare an
 163    uninitialized external linkage data object.  Under SVR4,
 164    the linker seems to want the alignment of data objects
 165    to depend on their types.  We do exactly that here.  */
 166
 167 #define COMMON_ASM_OP   "\t.comm\t"
 168
 169 #undef  ASM_OUTPUT_ALIGNED_COMMON
 170 #define ASM_OUTPUT_ALIGNED_COMMON(FILE, NAME, SIZE, ALIGN)              \
 171   do                                                                    \
 172     {                                                                   \
 173       fprintf ((FILE), "%s", COMMON_ASM_OP);                            \
 174       assemble_name ((FILE), (NAME));                                   \
 175       fprintf ((FILE), ","HOST_WIDE_INT_PRINT_UNSIGNED",%u\n",          \
 176                (SIZE), (ALIGN) / BITS_PER_UNIT);                        \
 177     }                                                                   \
 178   while (0)
 179
 180 /* This says how to output assembler code to declare an
 181    uninitialized internal linkage data object.  Under SVR4,
 182    the linker seems to want the alignment of data objects
 183    to depend on their types.  We do exactly that here.  */
 184
 185 #define LOCAL_ASM_OP    "\t.local\t"
 186
 187 #undef  ASM_OUTPUT_ALIGNED_LOCAL
 188 #define ASM_OUTPUT_ALIGNED_LOCAL(FILE, NAME, SIZE, ALIGN)       \
 189   do                                                            \
 190     {                                                           \
 191       fprintf ((FILE), "%s", LOCAL_ASM_OP);                     \
 192       assemble_name ((FILE), (NAME));                           \
 193       fprintf ((FILE), "\n");                                   \
 194       ASM_OUTPUT_ALIGNED_COMMON (FILE, NAME, SIZE, ALIGN);      \
 195     }                                                           \
 196   while (0)
 197
 198 /* This is the pseudo-op used to generate a contiguous sequence of byte
 199    values from a double-quoted string WITHOUT HAVING A TERMINATING NUL
 200    AUTOMATICALLY APPENDED.  This is the same for most svr4 assemblers.  */
 201
 202 #undef  ASCII_DATA_ASM_OP
 203 #define ASCII_DATA_ASM_OP       "\t.ascii\t"
 204
 205 /* Support a read-only data section.  */
 206 #define READONLY_DATA_SECTION_ASM_OP    "\t.section\t.rodata"
 207
 208 /* On svr4, we *do* have support for the .init and .fini sections, and we
 209    can put stuff in there to be executed before and after `main'.  We let
 210    crtstuff.c and other files know this by defining the following symbols.
 211    The definitions say how to change sections to the .init and .fini
 212    sections.  This is the same for all known svr4 assemblers.  */
 213
 214 #define INIT_SECTION_ASM_OP     "\t.section\t.init"
 215 #define FINI_SECTION_ASM_OP     "\t.section\t.fini"
 216
 217 /* Output assembly directive to move to the beginning of current section.  */
 218 #ifdef HAVE_GAS_SUBSECTION_ORDERING
 219 # define ASM_SECTION_START_OP   "\t.subsection\t-1"
 220 # define ASM_OUTPUT_SECTION_START(FILE) \
 221   fprintf ((FILE), "%s\n", ASM_SECTION_START_OP)
 222 #endif
 223
 224 #define MAKE_DECL_ONE_ONLY(DECL) (DECL_WEAK (DECL) = 1)
 225
 226 /* Switch into a generic section.  */
 227 #define TARGET_ASM_NAMED_SECTION  default_elf_asm_named_section
 228
 229 #undef  TARGET_ASM_SELECT_RTX_SECTION
 230 #define TARGET_ASM_SELECT_RTX_SECTION default_elf_select_rtx_section
 231 #undef  TARGET_ASM_SELECT_SECTION
 232 #define TARGET_ASM_SELECT_SECTION default_elf_select_section
 233
 234 /* Define the strings used for the special svr4 .type and .size directives.
 235    These strings generally do not vary from one system running svr4 to
 236    another, but if a given system (e.g. m88k running svr) needs to use
 237    different pseudo-op names for these, they may be overridden in the
 238    file which includes this one.  */
 239
 240 #define TYPE_ASM_OP     "\t.type\t"
 241 #define SIZE_ASM_OP     "\t.size\t"
 242
 243 /* This is how we tell the assembler that a symbol is weak.  */
 244
 245 #define ASM_WEAKEN_LABEL(FILE, NAME)    \
 246   do                                    \
 247     {                                   \
 248       fputs ("\t.weak\t", (FILE));      \
 249       assemble_name ((FILE), (NAME));   \
 250       fputc ('\n', (FILE));             \
 251     }                                   \
 252   while (0)
 253
 254 /* The following macro defines the format used to output the second
 255    operand of the .type assembler directive.  Different svr4 assemblers
 256    expect various different forms for this operand.  The one given here
 257    is just a default.  You may need to override it in your machine-
 258    specific tm.h file (depending upon the particulars of your assembler).  */
 259
 260 #define TYPE_OPERAND_FMT        "@%s"
 261
 262 /* Write the extra assembler code needed to declare a function's result.
 263    Most svr4 assemblers don't require any special declaration of the
 264    result value, but there are exceptions.  */
 265
 266 #ifndef ASM_DECLARE_RESULT
 267 #define ASM_DECLARE_RESULT(FILE, RESULT)
 268 #endif
 269
 270 /* These macros generate the special .type and .size directives which
 271    are used to set the corresponding fields of the linker symbol table
 272    entries in an ELF object file under SVR4.  These macros also output
 273    the starting labels for the relevant functions/objects.  */
 274
 275 /* Write the extra assembler code needed to declare a function properly.
 276    Some svr4 assemblers need to also have something extra said about the
 277    function's return value.  We allow for that here.  */
 278
 279 #ifndef ASM_DECLARE_FUNCTION_NAME
 280 #define ASM_DECLARE_FUNCTION_NAME(FILE, NAME, DECL)             \
 281   do                                                            \
 282     {                                                           \
 283       ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "function");       \
 284       ASM_DECLARE_RESULT (FILE, DECL_RESULT (DECL));            \
 285       ASM_OUTPUT_LABEL (FILE, NAME);                            \
 286     }                                                           \
 287   while (0)
 288 #endif
 289
 290 /* Write the extra assembler code needed to declare an object properly.  */
 291
 292 #define ASM_DECLARE_OBJECT_NAME(FILE, NAME, DECL)               \
 293   do                                                            \
 294     {                                                           \
 295       HOST_WIDE_INT size;                                       \
 296                                                                 \
 297       ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "object");         \
 298                                                                 \
 299       size_directive_output = 0;                                \
 300       if (!flag_inhibit_size_directive                          \
 301           && (DECL) && DECL_SIZE (DECL))                        \
 302         {                                                       \
 303           size_directive_output = 1;                            \
 304           size = int_size_in_bytes (TREE_TYPE (DECL));          \
 305           ASM_OUTPUT_SIZE_DIRECTIVE (FILE, NAME, size);         \
 306         }                                                       \
 307                                                                 \
 308       ASM_OUTPUT_LABEL (FILE, NAME);                            \
 309     }                                                           \
 310   while (0)
 311
 312 /* Output the size directive for a decl in rest_of_decl_compilation
 313    in the case where we did not do so before the initializer.
 314    Once we find the error_mark_node, we know that the value of
 315    size_directive_output was set
 316    by ASM_DECLARE_OBJECT_NAME when it was run for the same decl.  */
 317
 318 #undef ASM_FINISH_DECLARE_OBJECT
 319 #define ASM_FINISH_DECLARE_OBJECT(FILE, DECL, TOP_LEVEL, AT_END)\
 320   do                                                            \
 321     {                                                           \
 322       const char *name = XSTR (XEXP (DECL_RTL (DECL), 0), 0);   \
 323       HOST_WIDE_INT size;                                       \
 324                                                                 \
 325       if (!flag_inhibit_size_directive                          \
 326           && DECL_SIZE (DECL)                                   \
 327           && ! AT_END && TOP_LEVEL                              \
 328           && DECL_INITIAL (DECL) == error_mark_node             \
 329           && !size_directive_output)                            \
 330         {                                                       \
 331           size_directive_output = 1;                            \
 332           size = int_size_in_bytes (TREE_TYPE (DECL));          \
 333           ASM_OUTPUT_SIZE_DIRECTIVE (FILE, name, size);         \
 334         }                                                       \
 335     }                                                           \
 336   while (0)
 337
 338 /* This is how to declare the size of a function.  */
 339 #ifndef ASM_DECLARE_FUNCTION_SIZE
 340 #define ASM_DECLARE_FUNCTION_SIZE(FILE, FNAME, DECL)            \
 341   do                                                            \
 342     {                                                           \
 343       if (!flag_inhibit_size_directive)                         \
 344         ASM_OUTPUT_MEASURED_SIZE (FILE, FNAME);                 \
 345     }                                                           \
 346   while (0)
 347 #endif
 348
 349 /* A table of bytes codes used by the ASM_OUTPUT_ASCII and
 350    ASM_OUTPUT_LIMITED_STRING macros.  Each byte in the table
 351    corresponds to a particular byte value [0..255].  For any
 352    given byte value, if the value in the corresponding table
 353    position is zero, the given character can be output directly.
 354    If the table value is 1, the byte must be output as a \ooo
 355    octal escape.  If the tables value is anything else, then the
 356    byte value should be output as a \ followed by the value
 357    in the table.  Note that we can use standard UN*X escape
 358    sequences for many control characters, but we don't use
 359    \a to represent BEL because some svr4 assemblers (e.g. on
 360    the i386) don't know about that.  Also, we don't use \v
 361    since some versions of gas, such as 2.2 did not accept it.  */
 362
 363 #define ESCAPES \
 364 "\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\
 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\
 366 \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\
 367 \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\
 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 \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\
 371 \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"
 372
 373 /* Some svr4 assemblers have a limit on the number of characters which
 374    can appear in the operand of a .string directive.  If your assembler
 375    has such a limitation, you should define STRING_LIMIT to reflect that
 376    limit.  Note that at least some svr4 assemblers have a limit on the
 377    actual number of bytes in the double-quoted string, and that they
 378    count each character in an escape sequence as one byte.  Thus, an
 379    escape sequence like \377 would count as four bytes.
 380
 381    If your target assembler doesn't support the .string directive, you
 382    should define this to zero.
 383 */
 384
 385 #define STRING_LIMIT    ((unsigned) 256)
 386
 387 #define STRING_ASM_OP   "\t.string\t"
 388
 389 /* The routine used to output NUL terminated strings.  We use a special
 390    version of this for most svr4 targets because doing so makes the
 391    generated assembly code more compact (and thus faster to assemble)
 392    as well as more readable, especially for targets like the i386
 393    (where the only alternative is to output character sequences as
 394    comma separated lists of numbers).  */
 395
 396 #define ASM_OUTPUT_LIMITED_STRING(FILE, STR)            \
 397   do                                                    \
 398     {                                                   \
 399       register const unsigned char *_limited_str =      \
 400         (const unsigned char *) (STR);                  \
 401       register unsigned ch;                             \
 402                                                         \
 403       fprintf ((FILE), "%s\"", STRING_ASM_OP);          \
 404                                                         \
 405       for (; (ch = *_limited_str); _limited_str++)      \
 406         {                                               \
 407           register int escape;                          \
 408                                                         \
 409           switch (escape = ESCAPES[ch])                 \
 410             {                                           \
 411             case 0:                                     \
 412               putc (ch, (FILE));                        \
 413               break;                                    \
 414             case 1:                                     \
 415               fprintf ((FILE), "\\%03o", ch);           \
 416               break;                                    \
 417             default:                                    \
 418               putc ('\\', (FILE));                      \
 419               putc (escape, (FILE));                    \
 420               break;                                    \
 421             }                                           \
 422         }                                               \
 423                                                         \
 424       fprintf ((FILE), "\"\n");                         \
 425     }                                                   \
 426   while (0)
 427
 428 /* The routine used to output sequences of byte values.  We use a special
 429    version of this for most svr4 targets because doing so makes the
 430    generated assembly code more compact (and thus faster to assemble)
 431    as well as more readable.  Note that if we find subparts of the
 432    character sequence which end with NUL (and which are shorter than
 433    STRING_LIMIT) we output those using ASM_OUTPUT_LIMITED_STRING.  */
 434
 435 #undef  ASM_OUTPUT_ASCII
 436 #define ASM_OUTPUT_ASCII(FILE, STR, LENGTH)                             \
 437   do                                                                    \
 438     {                                                                   \
 439       register const unsigned char *_ascii_bytes =                      \
 440         (const unsigned char *) (STR);                                  \
 441       register const unsigned char *limit = _ascii_bytes + (LENGTH);    \
 442       register unsigned bytes_in_chunk = 0;                             \
 443                                                                         \
 444       for (; _ascii_bytes < limit; _ascii_bytes++)                      \
 445         {                                                               \
 446           register const unsigned char *p;                              \
 447                                                                         \
 448           if (bytes_in_chunk >= 60)                                     \
 449             {                                                           \
 450               fprintf ((FILE), "\"\n");                                 \
 451               bytes_in_chunk = 0;                                       \
 452             }                                                           \
 453                                                                         \
 454           for (p = _ascii_bytes; p < limit && *p != '\0'; p++)          \
 455             continue;                                                   \
 456                                                                         \
 457           if (p < limit && (p - _ascii_bytes) <= (long)STRING_LIMIT)    \
 458             {                                                           \
 459               if (bytes_in_chunk > 0)                                   \
 460                 {                                                       \
 461                   fprintf ((FILE), "\"\n");                             \
 462                   bytes_in_chunk = 0;                                   \
 463                 }                                                       \
 464                                                                         \
 465               ASM_OUTPUT_LIMITED_STRING ((FILE), _ascii_bytes);         \
 466               _ascii_bytes = p;                                         \
 467             }                                                           \
 468           else                                                          \
 469             {                                                           \
 470               register int escape;                                      \
 471               register unsigned ch;                                     \
 472                                                                         \
 473               if (bytes_in_chunk == 0)                                  \
 474                 fprintf ((FILE), "%s\"", ASCII_DATA_ASM_OP);            \
 475                                                                         \
 476               switch (escape = ESCAPES[ch = *_ascii_bytes])             \
 477                 {                                                       \
 478                 case 0:                                                 \
 479                   putc (ch, (FILE));                                    \
 480                   bytes_in_chunk++;                                     \
 481                   break;                                                \
 482                 case 1:                                                 \
 483                   fprintf ((FILE), "\\%03o", ch);                       \
 484                   bytes_in_chunk += 4;                                  \
 485                   break;                                                \
 486                 default:                                                \
 487                   putc ('\\', (FILE));                                  \
 488                   putc (escape, (FILE));                                \
 489                   bytes_in_chunk += 2;                                  \
 490                   break;                                                \
 491                 }                                                       \
 492             }                                                           \
 493         }                                                               \
 494                                                                         \
 495       if (bytes_in_chunk > 0)                                           \
 496         fprintf ((FILE), "\"\n");                                       \
 497     }                                                                   \
 498   while (0)