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
   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 bitfield forces int alignment for the structure.  */
  50
  51 #define PCC_BITFIELD_TYPE_MATTERS 1
  52
  53 /* Implicit library calls should use memcpy, not bcopy, etc.  */
  54
  55 #define TARGET_MEM_FUNCTIONS
  56
  57 /* Handle #pragma weak and #pragma pack.  */
  58
  59 #define HANDLE_SYSV_PRAGMA
  60
  61 /* System V Release 4 uses DWARF debugging info.  */
  62
  63 #define DWARF_DEBUGGING_INFO 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 /* This is how to begin an assembly language file.  Most svr4 assemblers want
  92    at least a .file directive to come first, and some want to see a .version
  93    directive come right after that.  Here we just establish a default
  94    which generates only the .file directive.  If you need a .version
  95    directive for any specific target, you should override this definition
  96    in the target-specific file which includes this one.  */
  97
  98 #undef ASM_FILE_START
  99 #define ASM_FILE_START(FILE)                            \
 100   output_file_directive ((FILE), main_input_filename)
 101
 102 /* This is how to allocate empty space in some section.  The .zero
 103    pseudo-op is used for this on most svr4 assemblers.  */
 104
 105 #define SKIP_ASM_OP     "\t.zero\t"
 106
 107 #undef  ASM_OUTPUT_SKIP
 108 #define ASM_OUTPUT_SKIP(FILE, SIZE) \
 109   fprintf (FILE, "%s%u\n", SKIP_ASM_OP, (SIZE))
 110
 111 /* This is how to output an internal numbered label where
 112    PREFIX is the class of label and NUM is the number within the class.
 113
 114    For most svr4 systems, the convention is that any symbol which begins
 115    with a period is not put into the linker symbol table by the assembler.  */
 116
 117 #undef  ASM_OUTPUT_INTERNAL_LABEL
 118 #define ASM_OUTPUT_INTERNAL_LABEL(FILE, PREFIX, NUM)            \
 119   do                                                            \
 120     {                                                           \
 121       fprintf (FILE, ".%s%u:\n", PREFIX, (unsigned) (NUM));     \
 122     }                                                           \
 123   while (0)
 124
 125 /* This is how to store into the string LABEL
 126    the symbol_ref name of an internal numbered label where
 127    PREFIX is the class of label and NUM is the number within the class.
 128    This is suitable for output with `assemble_name'.
 129
 130    For most svr4 systems, the convention is that any symbol which begins
 131    with a period is not put into the linker symbol table by the assembler.  */
 132
 133 #undef  ASM_GENERATE_INTERNAL_LABEL
 134 #define ASM_GENERATE_INTERNAL_LABEL(LABEL, PREFIX, NUM)         \
 135   do                                                            \
 136     {                                                           \
 137       sprintf (LABEL, "*.%s%u", PREFIX, (unsigned) (NUM));      \
 138     }                                                           \
 139   while (0)
 140
 141 /* Output the label which precedes a jumptable.  Note that for all svr4
 142    systems where we actually generate jumptables (which is to say every
 143    svr4 target except i386, where we use casesi instead) we put the jump-
 144    tables into the .rodata section and since other stuff could have been
 145    put into the .rodata section prior to any given jumptable, we have to
 146    make sure that the location counter for the .rodata section gets pro-
 147    perly re-aligned prior to the actual beginning of the jump table.  */
 148
 149 #undef ALIGN_ASM_OP
 150 #define ALIGN_ASM_OP "\t.align\t"
 151
 152 #ifndef ASM_OUTPUT_BEFORE_CASE_LABEL
 153 #define ASM_OUTPUT_BEFORE_CASE_LABEL(FILE, PREFIX, NUM, TABLE) \
 154   ASM_OUTPUT_ALIGN ((FILE), 2);
 155 #endif
 156
 157 #undef  ASM_OUTPUT_CASE_LABEL
 158 #define ASM_OUTPUT_CASE_LABEL(FILE, PREFIX, NUM, JUMPTABLE)             \
 159   do                                                                    \
 160     {                                                                   \
 161       ASM_OUTPUT_BEFORE_CASE_LABEL (FILE, PREFIX, NUM, JUMPTABLE)       \
 162         ASM_OUTPUT_INTERNAL_LABEL (FILE, PREFIX, NUM);                  \
 163     }                                                                   \
 164   while (0)
 165
 166 /* The standard SVR4 assembler seems to require that certain builtin
 167    library routines (e.g. .udiv) be explicitly declared as .globl
 168    in each assembly file where they are referenced.  */
 169
 170 #define ASM_OUTPUT_EXTERNAL_LIBCALL(FILE, FUN)  \
 171   (*targetm.asm_out.globalize_label) (FILE, XSTR (FUN, 0))
 172
 173 /* This says how to output assembler code to declare an
 174    uninitialized external linkage data object.  Under SVR4,
 175    the linker seems to want the alignment of data objects
 176    to depend on their types.  We do exactly that here.  */
 177
 178 #define COMMON_ASM_OP   "\t.comm\t"
 179
 180 #undef  ASM_OUTPUT_ALIGNED_COMMON
 181 #define ASM_OUTPUT_ALIGNED_COMMON(FILE, NAME, SIZE, ALIGN)              \
 182   do                                                                    \
 183     {                                                                   \
 184       fprintf ((FILE), "%s", COMMON_ASM_OP);                            \
 185       assemble_name ((FILE), (NAME));                                   \
 186       fprintf ((FILE), ",%u,%u\n", (SIZE), (ALIGN) / BITS_PER_UNIT);    \
 187     }                                                                   \
 188   while (0)
 189
 190 /* This says how to output assembler code to declare an
 191    uninitialized internal linkage data object.  Under SVR4,
 192    the linker seems to want the alignment of data objects
 193    to depend on their types.  We do exactly that here.  */
 194
 195 #define LOCAL_ASM_OP    "\t.local\t"
 196
 197 #undef  ASM_OUTPUT_ALIGNED_LOCAL
 198 #define ASM_OUTPUT_ALIGNED_LOCAL(FILE, NAME, SIZE, ALIGN)       \
 199   do                                                            \
 200     {                                                           \
 201       fprintf ((FILE), "%s", LOCAL_ASM_OP);                     \
 202       assemble_name ((FILE), (NAME));                           \
 203       fprintf ((FILE), "\n");                                   \
 204       ASM_OUTPUT_ALIGNED_COMMON (FILE, NAME, SIZE, ALIGN);      \
 205     }                                                           \
 206   while (0)
 207
 208 /* This is the pseudo-op used to generate a contiguous sequence of byte
 209    values from a double-quoted string WITHOUT HAVING A TERMINATING NUL
 210    AUTOMATICALLY APPENDED.  This is the same for most svr4 assemblers.  */
 211
 212 #undef  ASCII_DATA_ASM_OP
 213 #define ASCII_DATA_ASM_OP       "\t.ascii\t"
 214
 215 /* Support a read-only data section.  */
 216 #define READONLY_DATA_SECTION_ASM_OP    "\t.section\t.rodata"
 217
 218 /* On svr4, we *do* have support for the .init and .fini sections, and we
 219    can put stuff in there to be executed before and after `main'.  We let
 220    crtstuff.c and other files know this by defining the following symbols.
 221    The definitions say how to change sections to the .init and .fini
 222    sections.  This is the same for all known svr4 assemblers.  */
 223
 224 #define INIT_SECTION_ASM_OP     "\t.section\t.init"
 225 #define FINI_SECTION_ASM_OP     "\t.section\t.fini"
 226
 227 /* Output assembly directive to move to the beginning of current section.  */
 228 #ifdef HAVE_GAS_SUBSECTION_ORDERING
 229 # define ASM_SECTION_START_OP   "\t.subsection\t-1"
 230 # define ASM_OUTPUT_SECTION_START(FILE) \
 231   fprintf ((FILE), "%s\n", ASM_SECTION_START_OP)
 232 #endif
 233
 234 #define MAKE_DECL_ONE_ONLY(DECL) (DECL_WEAK (DECL) = 1)
 235
 236 /* Switch into a generic section.  */
 237 #define TARGET_ASM_NAMED_SECTION  default_elf_asm_named_section
 238
 239 #undef  TARGET_ASM_SELECT_RTX_SECTION
 240 #define TARGET_ASM_SELECT_RTX_SECTION default_elf_select_rtx_section
 241 #undef  TARGET_ASM_SELECT_SECTION
 242 #define TARGET_ASM_SELECT_SECTION default_elf_select_section
 243
 244 /* Define the strings used for the special svr4 .type and .size directives.
 245    These strings generally do not vary from one system running svr4 to
 246    another, but if a given system (e.g. m88k running svr) needs to use
 247    different pseudo-op names for these, they may be overridden in the
 248    file which includes this one.  */
 249
 250 #define TYPE_ASM_OP     "\t.type\t"
 251 #define SIZE_ASM_OP     "\t.size\t"
 252
 253 /* This is how we tell the assembler that a symbol is weak.  */
 254
 255 #define ASM_WEAKEN_LABEL(FILE, NAME)    \
 256   do                                    \
 257     {                                   \
 258       fputs ("\t.weak\t", (FILE));      \
 259       assemble_name ((FILE), (NAME));   \
 260       fputc ('\n', (FILE));             \
 261     }                                   \
 262   while (0)
 263
 264 /* The following macro defines the format used to output the second
 265    operand of the .type assembler directive.  Different svr4 assemblers
 266    expect various different forms for this operand.  The one given here
 267    is just a default.  You may need to override it in your machine-
 268    specific tm.h file (depending upon the particulars of your assembler).  */
 269
 270 #define TYPE_OPERAND_FMT        "@%s"
 271
 272 /* Write the extra assembler code needed to declare a function's result.
 273    Most svr4 assemblers don't require any special declaration of the
 274    result value, but there are exceptions.  */
 275
 276 #ifndef ASM_DECLARE_RESULT
 277 #define ASM_DECLARE_RESULT(FILE, RESULT)
 278 #endif
 279
 280 /* These macros generate the special .type and .size directives which
 281    are used to set the corresponding fields of the linker symbol table
 282    entries in an ELF object file under SVR4.  These macros also output
 283    the starting labels for the relevant functions/objects.  */
 284
 285 /* Write the extra assembler code needed to declare a function properly.
 286    Some svr4 assemblers need to also have something extra said about the
 287    function's return value.  We allow for that here.  */
 288
 289 #ifndef ASM_DECLARE_FUNCTION_NAME
 290 #define ASM_DECLARE_FUNCTION_NAME(FILE, NAME, DECL)             \
 291   do                                                            \
 292     {                                                           \
 293       ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "function");       \
 294       ASM_DECLARE_RESULT (FILE, DECL_RESULT (DECL));            \
 295       ASM_OUTPUT_LABEL (FILE, NAME);                            \
 296     }                                                           \
 297   while (0)
 298 #endif
 299
 300 /* Write the extra assembler code needed to declare an object properly.  */
 301
 302 #define ASM_DECLARE_OBJECT_NAME(FILE, NAME, DECL)               \
 303   do                                                            \
 304     {                                                           \
 305       HOST_WIDE_INT size;                                       \
 306                                                                 \
 307       ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "object");         \
 308                                                                 \
 309       size_directive_output = 0;                                \
 310       if (!flag_inhibit_size_directive                          \
 311           && (DECL) && DECL_SIZE (DECL))                        \
 312         {                                                       \
 313           size_directive_output = 1;                            \
 314           size = int_size_in_bytes (TREE_TYPE (DECL));          \
 315           ASM_OUTPUT_SIZE_DIRECTIVE (FILE, NAME, size);         \
 316         }                                                       \
 317                                                                 \
 318       ASM_OUTPUT_LABEL (FILE, NAME);                            \
 319     }                                                           \
 320   while (0)
 321
 322 /* Output the size directive for a decl in rest_of_decl_compilation
 323    in the case where we did not do so before the initializer.
 324    Once we find the error_mark_node, we know that the value of
 325    size_directive_output was set
 326    by ASM_DECLARE_OBJECT_NAME when it was run for the same decl.  */
 327
 328 #define ASM_FINISH_DECLARE_OBJECT(FILE, DECL, TOP_LEVEL, AT_END)\
 329   do                                                            \
 330     {                                                           \
 331       const char *name = XSTR (XEXP (DECL_RTL (DECL), 0), 0);   \
 332       HOST_WIDE_INT size;                                       \
 333                                                                 \
 334       if (!flag_inhibit_size_directive                          \
 335           && DECL_SIZE (DECL)                                   \
 336           && ! AT_END && TOP_LEVEL                              \
 337           && DECL_INITIAL (DECL) == error_mark_node             \
 338           && !size_directive_output)                            \
 339         {                                                       \
 340           size_directive_output = 1;                            \
 341           size = int_size_in_bytes (TREE_TYPE (DECL));          \
 342           ASM_OUTPUT_SIZE_DIRECTIVE (FILE, name, size);         \
 343         }                                                       \
 344     }                                                           \
 345   while (0)
 346
 347 /* This is how to declare the size of a function.  */
 348 #ifndef ASM_DECLARE_FUNCTION_SIZE
 349 #define ASM_DECLARE_FUNCTION_SIZE(FILE, FNAME, DECL)            \
 350   do                                                            \
 351     {                                                           \
 352       if (!flag_inhibit_size_directive)                         \
 353         ASM_OUTPUT_MEASURED_SIZE (FILE, FNAME);                 \
 354     }                                                           \
 355   while (0)
 356 #endif
 357
 358 /* A table of bytes codes used by the ASM_OUTPUT_ASCII and
 359    ASM_OUTPUT_LIMITED_STRING macros.  Each byte in the table
 360    corresponds to a particular byte value [0..255].  For any
 361    given byte value, if the value in the corresponding table
 362    position is zero, the given character can be output directly.
 363    If the table value is 1, the byte must be output as a \ooo
 364    octal escape.  If the tables value is anything else, then the
 365    byte value should be output as a \ followed by the value
 366    in the table.  Note that we can use standard UN*X escape
 367    sequences for many control characters, but we don't use
 368    \a to represent BEL because some svr4 assemblers (e.g. on
 369    the i386) don't know about that.  Also, we don't use \v
 370    since some versions of gas, such as 2.2 did not accept it.  */
 371
 372 #define ESCAPES \
 373 "\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\
 374 \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\
 375 \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\
 376 \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\
 377 \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\
 378 \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\
 379 \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\
 380 \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"
 381
 382 /* Some svr4 assemblers have a limit on the number of characters which
 383    can appear in the operand of a .string directive.  If your assembler
 384    has such a limitation, you should define STRING_LIMIT to reflect that
 385    limit.  Note that at least some svr4 assemblers have a limit on the
 386    actual number of bytes in the double-quoted string, and that they
 387    count each character in an escape sequence as one byte.  Thus, an
 388    escape sequence like \377 would count as four bytes.
 389
 390    If your target assembler doesn't support the .string directive, you
 391    should define this to zero.
 392 */
 393
 394 #define STRING_LIMIT    ((unsigned) 256)
 395
 396 #define STRING_ASM_OP   "\t.string\t"
 397
 398 /* The routine used to output NUL terminated strings.  We use a special
 399    version of this for most svr4 targets because doing so makes the
 400    generated assembly code more compact (and thus faster to assemble)
 401    as well as more readable, especially for targets like the i386
 402    (where the only alternative is to output character sequences as
 403    comma separated lists of numbers).   */
 404
 405 #define ASM_OUTPUT_LIMITED_STRING(FILE, STR)            \
 406   do                                                    \
 407     {                                                   \
 408       register const unsigned char *_limited_str =      \
 409         (const unsigned char *) (STR);                  \
 410       register unsigned ch;                             \
 411                                                         \
 412       fprintf ((FILE), "%s\"", STRING_ASM_OP);          \
 413                                                         \
 414       for (; (ch = *_limited_str); _limited_str++)      \
 415         {                                               \
 416           register int escape;                          \
 417                                                         \
 418           switch (escape = ESCAPES[ch])                 \
 419             {                                           \
 420             case 0:                                     \
 421               putc (ch, (FILE));                        \
 422               break;                                    \
 423             case 1:                                     \
 424               fprintf ((FILE), "\\%03o", ch);           \
 425               break;                                    \
 426             default:                                    \
 427               putc ('\\', (FILE));                      \
 428               putc (escape, (FILE));                    \
 429               break;                                    \
 430             }                                           \
 431         }                                               \
 432                                                         \
 433       fprintf ((FILE), "\"\n");                         \
 434     }                                                   \
 435   while (0)
 436
 437 /* The routine used to output sequences of byte values.  We use a special
 438    version of this for most svr4 targets because doing so makes the
 439    generated assembly code more compact (and thus faster to assemble)
 440    as well as more readable.  Note that if we find subparts of the
 441    character sequence which end with NUL (and which are shorter than
 442    STRING_LIMIT) we output those using ASM_OUTPUT_LIMITED_STRING.  */
 443
 444 #undef  ASM_OUTPUT_ASCII
 445 #define ASM_OUTPUT_ASCII(FILE, STR, LENGTH)                             \
 446   do                                                                    \
 447     {                                                                   \
 448       register const unsigned char *_ascii_bytes =                      \
 449         (const unsigned char *) (STR);                                  \
 450       register const unsigned char *limit = _ascii_bytes + (LENGTH);    \
 451       register unsigned bytes_in_chunk = 0;                             \
 452                                                                         \
 453       for (; _ascii_bytes < limit; _ascii_bytes++)                      \
 454         {                                                               \
 455           register const unsigned char *p;                              \
 456                                                                         \
 457           if (bytes_in_chunk >= 60)                                     \
 458             {                                                           \
 459               fprintf ((FILE), "\"\n");                                 \
 460               bytes_in_chunk = 0;                                       \
 461             }                                                           \
 462                                                                         \
 463           for (p = _ascii_bytes; p < limit && *p != '\0'; p++)          \
 464             continue;                                                   \
 465                                                                         \
 466           if (p < limit && (p - _ascii_bytes) <= (long)STRING_LIMIT)    \
 467             {                                                           \
 468               if (bytes_in_chunk > 0)                                   \
 469                 {                                                       \
 470                   fprintf ((FILE), "\"\n");                             \
 471                   bytes_in_chunk = 0;                                   \
 472                 }                                                       \
 473                                                                         \
 474               ASM_OUTPUT_LIMITED_STRING ((FILE), _ascii_bytes);         \
 475               _ascii_bytes = p;                                         \
 476             }                                                           \
 477           else                                                          \
 478             {                                                           \
 479               register int escape;                                      \
 480               register unsigned ch;                                     \
 481                                                                         \
 482               if (bytes_in_chunk == 0)                                  \
 483                 fprintf ((FILE), "%s\"", ASCII_DATA_ASM_OP);            \
 484                                                                         \
 485               switch (escape = ESCAPES[ch = *_ascii_bytes])             \
 486                 {                                                       \
 487                 case 0:                                                 \
 488                   putc (ch, (FILE));                                    \
 489                   bytes_in_chunk++;                                     \
 490                   break;                                                \
 491                 case 1:                                                 \
 492                   fprintf ((FILE), "\\%03o", ch);                       \
 493                   bytes_in_chunk += 4;                                  \
 494                   break;                                                \
 495                 default:                                                \
 496                   putc ('\\', (FILE));                                  \
 497                   putc (escape, (FILE));                                \
 498                   bytes_in_chunk += 2;                                  \
 499                   break;                                                \
 500                 }                                                       \
 501             }                                                           \
 502         }                                                               \
 503                                                                         \
 504       if (bytes_in_chunk > 0)                                           \
 505         fprintf ((FILE), "\"\n");                                       \
 506     }                                                                   \
 507   while (0)