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    2007, 2009, 2010 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 3, 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 Under Section 7 of GPL version 3, you are granted additional
  20 permissions described in the GCC Runtime Library Exception, version
  21 3.1, as published by the Free Software Foundation.
  22
  23 You should have received a copy of the GNU General Public License and
  24 a copy of the GCC Runtime Library Exception along with this program;
  25 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  26 <http://www.gnu.org/licenses/>.  */
  27
  28 #define TARGET_OBJFMT_CPP_BUILTINS()            \
  29   do                                            \
  30     {                                           \
  31         builtin_define ("__ELF__");             \
  32     }                                           \
  33   while (0)
  34
  35 /* Define a symbol indicating that we are using elfos.h.
  36    Some CPU specific configuration files use this.  */
  37 #define USING_ELFOS_H
  38
  39 /* The prefix to add to user-visible assembler symbols.
  40
  41    For ELF systems the convention is *not* to prepend a leading
  42    underscore onto user-level symbol names.  */
  43
  44 #undef  USER_LABEL_PREFIX
  45 #define USER_LABEL_PREFIX ""
  46
  47 /* The biggest alignment supported by ELF in bits. 32-bit ELF
  48    supports section alignment up to (0x80000000 * 8), while
  49    64-bit ELF supports (0x8000000000000000 * 8). If this macro
  50    is not defined, the default is the largest alignment supported
  51    by 32-bit ELF and representable on a 32-bit host. Use this
  52    macro to limit the alignment which can be specified using
  53    the `__attribute__ ((aligned (N)))' construct.  */
  54 #ifndef MAX_OFILE_ALIGNMENT
  55 #define MAX_OFILE_ALIGNMENT (((unsigned int) 1 << 28) * 8)
  56 #endif
  57
  58 /* Use periods rather than dollar signs in special g++ assembler names.  */
  59
  60 #define NO_DOLLAR_IN_LABEL
  61
  62 /* Writing `int' for a bit-field forces int alignment for the structure.  */
  63
  64 #ifndef PCC_BITFIELD_TYPE_MATTERS
  65 #define PCC_BITFIELD_TYPE_MATTERS 1
  66 #endif
  67
  68 /* All ELF targets can support DWARF-2.  */
  69
  70 #define DWARF2_DEBUGGING_INFO 1
  71
  72 /* The GNU tools operate better with dwarf2, and it is required by some
  73    psABI's.  Since we don't have any native tools to be compatible with,
  74    default to dwarf2.  */
  75
  76 #ifndef PREFERRED_DEBUGGING_TYPE
  77 #define PREFERRED_DEBUGGING_TYPE DWARF2_DEBUG
  78 #endif
  79
  80 /* All SVR4 targets use the ELF object file format.  */
  81 #define OBJECT_FORMAT_ELF
  82
  83
  84 /* Output #ident as a .ident.  */
  85
  86 #undef TARGET_ASM_OUTPUT_IDENT
  87 #define TARGET_ASM_OUTPUT_IDENT default_asm_output_ident_directive
  88
  89 #undef  SET_ASM_OP
  90 #define SET_ASM_OP      "\t.set\t"
  91
  92 /* Most svr4 assemblers want a .file directive at the beginning of
  93    their input file.  */
  94 #define TARGET_ASM_FILE_START_FILE_DIRECTIVE true
  95
  96 /* This is how to allocate empty space in some section.  The .zero
  97    pseudo-op is used for this on most svr4 assemblers.  */
  98
  99 #define SKIP_ASM_OP     "\t.zero\t"
 100
 101 #undef  ASM_OUTPUT_SKIP
 102 #define ASM_OUTPUT_SKIP(FILE, SIZE) \
 103    fprintf ((FILE), "%s"HOST_WIDE_INT_PRINT_UNSIGNED"\n",\
 104             SKIP_ASM_OP, (SIZE))
 105
 106 /* This is how to store into the string LABEL
 107    the symbol_ref name of an internal numbered label where
 108    PREFIX is the class of label and NUM is the number within the class.
 109    This is suitable for output with `assemble_name'.
 110
 111    For most svr4 systems, the convention is that any symbol which begins
 112    with a period is not put into the linker symbol table by the assembler.  */
 113
 114 #undef  ASM_GENERATE_INTERNAL_LABEL
 115 #define ASM_GENERATE_INTERNAL_LABEL(LABEL, PREFIX, NUM)         \
 116   do                                                            \
 117     {                                                           \
 118       char *__p;                                                \
 119       (LABEL)[0] = '*';                                         \
 120       (LABEL)[1] = '.';                                         \
 121       __p = stpcpy (&(LABEL)[2], PREFIX);                       \
 122       sprint_ul (__p, (unsigned long) (NUM));                   \
 123     }                                                           \
 124   while (0)
 125
 126 /* Output the label which precedes a jumptable.  Note that for all svr4
 127    systems where we actually generate jumptables (which is to say every
 128    svr4 target except i386, where we use casesi instead) we put the jump-
 129    tables into the .rodata section and since other stuff could have been
 130    put into the .rodata section prior to any given jumptable, we have to
 131    make sure that the location counter for the .rodata section gets pro-
 132    perly re-aligned prior to the actual beginning of the jump table.  */
 133
 134 #undef ALIGN_ASM_OP
 135 #define ALIGN_ASM_OP "\t.align\t"
 136
 137 #ifndef ASM_OUTPUT_BEFORE_CASE_LABEL
 138 #define ASM_OUTPUT_BEFORE_CASE_LABEL(FILE, PREFIX, NUM, TABLE) \
 139   ASM_OUTPUT_ALIGN ((FILE), 2);
 140 #endif
 141
 142 #undef  ASM_OUTPUT_CASE_LABEL
 143 #define ASM_OUTPUT_CASE_LABEL(FILE, PREFIX, NUM, JUMPTABLE)             \
 144   do                                                                    \
 145     {                                                                   \
 146       ASM_OUTPUT_BEFORE_CASE_LABEL (FILE, PREFIX, NUM, JUMPTABLE)       \
 147         (*targetm.asm_out.internal_label) (FILE, PREFIX, NUM);                  \
 148     }                                                                   \
 149   while (0)
 150
 151 /* The standard SVR4 assembler seems to require that certain builtin
 152    library routines (e.g. .udiv) be explicitly declared as .globl
 153    in each assembly file where they are referenced.  */
 154
 155 #define ASM_OUTPUT_EXTERNAL_LIBCALL(FILE, FUN)  \
 156   (*targetm.asm_out.globalize_label) (FILE, XSTR (FUN, 0))
 157
 158 /* This says how to output assembler code to declare an
 159    uninitialized external linkage data object.  Under SVR4,
 160    the linker seems to want the alignment of data objects
 161    to depend on their types.  We do exactly that here.  */
 162
 163 #define COMMON_ASM_OP   "\t.comm\t"
 164
 165 #undef  ASM_OUTPUT_ALIGNED_COMMON
 166 #define ASM_OUTPUT_ALIGNED_COMMON(FILE, NAME, SIZE, ALIGN)              \
 167   do                                                                    \
 168     {                                                                   \
 169       fprintf ((FILE), "%s", COMMON_ASM_OP);                            \
 170       assemble_name ((FILE), (NAME));                                   \
 171       fprintf ((FILE), ","HOST_WIDE_INT_PRINT_UNSIGNED",%u\n",          \
 172                (SIZE), (ALIGN) / BITS_PER_UNIT);                        \
 173     }                                                                   \
 174   while (0)
 175
 176 /* This says how to output assembler code to declare an
 177    uninitialized internal linkage data object.  Under SVR4,
 178    the linker seems to want the alignment of data objects
 179    to depend on their types.  We do exactly that here.  */
 180
 181 #define LOCAL_ASM_OP    "\t.local\t"
 182
 183 #undef  ASM_OUTPUT_ALIGNED_LOCAL
 184 #define ASM_OUTPUT_ALIGNED_LOCAL(FILE, NAME, SIZE, ALIGN)       \
 185   do                                                            \
 186     {                                                           \
 187       fprintf ((FILE), "%s", LOCAL_ASM_OP);                     \
 188       assemble_name ((FILE), (NAME));                           \
 189       fprintf ((FILE), "\n");                                   \
 190       ASM_OUTPUT_ALIGNED_COMMON (FILE, NAME, SIZE, ALIGN);      \
 191     }                                                           \
 192   while (0)
 193
 194 /* This is the pseudo-op used to generate a contiguous sequence of byte
 195    values from a double-quoted string WITHOUT HAVING A TERMINATING NUL
 196    AUTOMATICALLY APPENDED.  This is the same for most svr4 assemblers.  */
 197
 198 #undef  ASCII_DATA_ASM_OP
 199 #define ASCII_DATA_ASM_OP       "\t.ascii\t"
 200
 201 /* Support a read-only data section.  */
 202 #define READONLY_DATA_SECTION_ASM_OP    "\t.section\t.rodata"
 203
 204 /* On svr4, we *do* have support for the .init and .fini sections, and we
 205    can put stuff in there to be executed before and after `main'.  We let
 206    crtstuff.c and other files know this by defining the following symbols.
 207    The definitions say how to change sections to the .init and .fini
 208    sections.  This is the same for all known svr4 assemblers.  */
 209
 210 #define INIT_SECTION_ASM_OP     "\t.section\t.init"
 211 #define FINI_SECTION_ASM_OP     "\t.section\t.fini"
 212
 213 /* Output assembly directive to move to the beginning of current section.  */
 214 #ifdef HAVE_GAS_SUBSECTION_ORDERING
 215 # define ASM_SECTION_START_OP   "\t.subsection\t-1"
 216 # define ASM_OUTPUT_SECTION_START(FILE) \
 217   fprintf ((FILE), "%s\n", ASM_SECTION_START_OP)
 218 #endif
 219
 220 #define MAKE_DECL_ONE_ONLY(DECL) (DECL_WEAK (DECL) = 1)
 221
 222 /* Switch into a generic section.  */
 223 #define TARGET_ASM_NAMED_SECTION  default_elf_asm_named_section
 224
 225 #undef  TARGET_ASM_SELECT_RTX_SECTION
 226 #define TARGET_ASM_SELECT_RTX_SECTION default_elf_select_rtx_section
 227 #undef  TARGET_ASM_SELECT_SECTION
 228 #define TARGET_ASM_SELECT_SECTION default_elf_select_section
 229 #undef  TARGET_HAVE_SWITCHABLE_BSS_SECTIONS
 230 #define TARGET_HAVE_SWITCHABLE_BSS_SECTIONS true
 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_FUNCTION_LABEL (FILE, NAME, DECL);             \
 284     }                                                           \
 285   while (0)
 286 #endif
 287
 288 /* Write the extra assembler code needed to declare an object properly.  */
 289
 290 #ifdef HAVE_GAS_GNU_UNIQUE_OBJECT
 291 #define USE_GNU_UNIQUE_OBJECT 1
 292 #else
 293 #define USE_GNU_UNIQUE_OBJECT 0
 294 #endif
 295
 296 #define ASM_DECLARE_OBJECT_NAME(FILE, NAME, DECL)                       \
 297   do                                                                    \
 298     {                                                                   \
 299       HOST_WIDE_INT size;                                               \
 300                                                                         \
 301       /* For template static data member instantiations or              \
 302          inline fn local statics and their guard variables, use         \
 303          gnu_unique_object so that they will be combined even under     \
 304          RTLD_LOCAL.  Don't use gnu_unique_object for typeinfo,         \
 305          vtables and other read-only artificial decls.  */              \
 306       if (USE_GNU_UNIQUE_OBJECT && DECL_ONE_ONLY (DECL)                 \
 307           && (!DECL_ARTIFICIAL (DECL) || !TREE_READONLY (DECL)))        \
 308         ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "gnu_unique_object");    \
 309       else                                                              \
 310         ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "object");               \
 311                                                                         \
 312       size_directive_output = 0;                                        \
 313       if (!flag_inhibit_size_directive                                  \
 314           && (DECL) && DECL_SIZE (DECL))                                \
 315         {                                                               \
 316           size_directive_output = 1;                                    \
 317           size = int_size_in_bytes (TREE_TYPE (DECL));                  \
 318           ASM_OUTPUT_SIZE_DIRECTIVE (FILE, NAME, size);                 \
 319         }                                                               \
 320                                                                         \
 321       ASM_OUTPUT_LABEL (FILE, NAME);                                    \
 322     }                                                                   \
 323   while (0)
 324
 325 /* Output the size directive for a decl in rest_of_decl_compilation
 326    in the case where we did not do so before the initializer.
 327    Once we find the error_mark_node, we know that the value of
 328    size_directive_output was set
 329    by ASM_DECLARE_OBJECT_NAME when it was run for the same decl.  */
 330
 331 #undef ASM_FINISH_DECLARE_OBJECT
 332 #define ASM_FINISH_DECLARE_OBJECT(FILE, DECL, TOP_LEVEL, AT_END)\
 333   do                                                            \
 334     {                                                           \
 335       const char *name = XSTR (XEXP (DECL_RTL (DECL), 0), 0);   \
 336       HOST_WIDE_INT size;                                       \
 337                                                                 \
 338       if (!flag_inhibit_size_directive                          \
 339           && DECL_SIZE (DECL)                                   \
 340           && ! AT_END && TOP_LEVEL                              \
 341           && DECL_INITIAL (DECL) == error_mark_node             \
 342           && !size_directive_output)                            \
 343         {                                                       \
 344           size_directive_output = 1;                            \
 345           size = int_size_in_bytes (TREE_TYPE (DECL));          \
 346           ASM_OUTPUT_SIZE_DIRECTIVE (FILE, name, size);         \
 347         }                                                       \
 348     }                                                           \
 349   while (0)
 350
 351 /* This is how to declare the size of a function.  */
 352 #ifndef ASM_DECLARE_FUNCTION_SIZE
 353 #define ASM_DECLARE_FUNCTION_SIZE(FILE, FNAME, DECL)            \
 354   do                                                            \
 355     {                                                           \
 356       if (!flag_inhibit_size_directive)                         \
 357         ASM_OUTPUT_MEASURED_SIZE (FILE, FNAME);                 \
 358     }                                                           \
 359   while (0)
 360 #endif
 361
 362 /* A table of bytes codes used by the ASM_OUTPUT_ASCII and
 363    ASM_OUTPUT_LIMITED_STRING macros.  Each byte in the table
 364    corresponds to a particular byte value [0..255].  For any
 365    given byte value, if the value in the corresponding table
 366    position is zero, the given character can be output directly.
 367    If the table value is 1, the byte must be output as a \ooo
 368    octal escape.  If the tables value is anything else, then the
 369    byte value should be output as a \ followed by the value
 370    in the table.  Note that we can use standard UN*X escape
 371    sequences for many control characters, but we don't use
 372    \a to represent BEL because some svr4 assemblers (e.g. on
 373    the i386) don't know about that.  Also, we don't use \v
 374    since some versions of gas, such as 2.2 did not accept it.  */
 375
 376 #define ELF_ASCII_ESCAPES \
 377 "\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\
 378 \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\
 379 \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\
 380 \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\
 381 \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\
 382 \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\
 383 \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\
 384 \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"
 385
 386 /* Some svr4 assemblers have a limit on the number of characters which
 387    can appear in the operand of a .string directive.  If your assembler
 388    has such a limitation, you should define STRING_LIMIT to reflect that
 389    limit.  Note that at least some svr4 assemblers have a limit on the
 390    actual number of bytes in the double-quoted string, and that they
 391    count each character in an escape sequence as one byte.  Thus, an
 392    escape sequence like \377 would count as four bytes.
 393
 394    If your target assembler doesn't support the .string directive, you
 395    should define this to zero.
 396 */
 397
 398 #define ELF_STRING_LIMIT        ((unsigned) 256)
 399
 400 #define STRING_ASM_OP   "\t.string\t"
 401
 402 /* The routine used to output NUL terminated strings.  We use a special
 403    version of this for most svr4 targets because doing so makes the
 404    generated assembly code more compact (and thus faster to assemble)
 405    as well as more readable, especially for targets like the i386
 406    (where the only alternative is to output character sequences as
 407    comma separated lists of numbers).  */
 408
 409 #define ASM_OUTPUT_LIMITED_STRING(FILE, STR)            \
 410   default_elf_asm_output_limited_string ((FILE), (STR))
 411
 412 /* The routine used to output sequences of byte values.  We use a special
 413    version of this for most svr4 targets because doing so makes the
 414    generated assembly code more compact (and thus faster to assemble)
 415    as well as more readable.  Note that if we find subparts of the
 416    character sequence which end with NUL (and which are shorter than
 417    STRING_LIMIT) we output those using ASM_OUTPUT_LIMITED_STRING.  */
 418
 419 #undef  ASM_OUTPUT_ASCII
 420 #define ASM_OUTPUT_ASCII(FILE, STR, LENGTH)                     \
 421   default_elf_asm_output_ascii ((FILE), (STR), (LENGTH));
 422
 423 /* Allow the use of the -frecord-gcc-switches switch via the
 424    elf_record_gcc_switches function defined in varasm.c.  */
 425 #undef  TARGET_ASM_RECORD_GCC_SWITCHES
 426 #define TARGET_ASM_RECORD_GCC_SWITCHES elf_record_gcc_switches
 427
 428 /* A C statement (sans semicolon) to output to the stdio stream STREAM
 429    any text necessary for declaring the name of an external symbol
 430    named NAME which is referenced in this compilation but not defined.
 431    It is needed to properly support non-default visibility.  */
 432
 433 #ifndef ASM_OUTPUT_EXTERNAL
 434 #define ASM_OUTPUT_EXTERNAL(FILE, DECL, NAME) \
 435   default_elf_asm_output_external (FILE, DECL, NAME)
 436 #endif