gcc/config/arm/elf.h

   1 /* Definitions of target machine for GNU compiler.
   2    For ARM with ELF obj format.
   3    Copyright (C) 1995 - 1999 Free Software Foundation, Inc.
   4    Contributed by Philip Blundell <philb@gnu.org> and
   5    Catherine Moore <clm@cygnus.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 OBJECT_FORMAT_ELF
  26
  27 #ifndef LOCAL_LABEL_PREFIX
  28 #define LOCAL_LABEL_PREFIX "."
  29 #endif
  30
  31 #ifndef USER_LABEL_PREFIX
  32 #define USER_LABEL_PREFIX ""
  33 #endif
  34
  35 #ifndef SUBTARGET_CPP_SPEC
  36 #define SUBTARGET_CPP_SPEC  "-Darm_elf -D__ELF__"
  37 #endif
  38
  39 #ifndef SUBTARGET_EXTRA_ASM_SPEC
  40 #define SUBTARGET_EXTRA_ASM_SPEC
  41 #endif
  42
  43 #ifndef ASM_SPEC
  44 #define ASM_SPEC "\
  45 %{mbig-endian:-EB} \
  46 %{mcpu=*:-m%*} \
  47 %{march=*:-m%*} \
  48 %{mapcs-*:-mapcs-%*} \
  49 %{mapcs-float:-mfloat} \
  50 %{msoft-float:-mno-fpu} \
  51 %{mthumb-interwork:-mthumb-interwork} \
  52 " SUBTARGET_EXTRA_ASM_SPEC
  53 #endif
  54
  55 /* The following macro defines the format used to output the second
  56    operand of the .type assembler directive.  Different svr4 assemblers
  57    expect various different forms for this operand.  The one given here
  58    is just a default.  You may need to override it in your machine-
  59    specific tm.h file (depending upon the particulars of your assembler).  */
  60 #define TYPE_OPERAND_FMT        "%s"
  61
  62 /* Write the extra assembler code needed to declare a function's result.
  63    Most svr4 assemblers don't require any special declaration of the
  64    result value, but there are exceptions.  */
  65 #ifndef ASM_DECLARE_RESULT
  66 #define ASM_DECLARE_RESULT(FILE, RESULT)
  67 #endif
  68
  69 /* These macros generate the special .type and .size directives which
  70    are used to set the corresponding fields of the linker symbol table
  71    entries in an ELF object file under SVR4.  These macros also output
  72    the starting labels for the relevant functions/objects.  */
  73 #define TYPE_ASM_OP     ".type"
  74 #define SIZE_ASM_OP     ".size"
  75
  76 /* Write the extra assembler code needed to declare a function properly.
  77    Some svr4 assemblers need to also have something extra said about the
  78    function's return value.  We allow for that here.  */
  79 #define ASM_DECLARE_FUNCTION_NAME(FILE, NAME, DECL)     \
  80   do                                                    \
  81     {                                                   \
  82       ARM_DECLARE_FUNCTION_NAME (FILE, NAME, DECL);     \
  83       fprintf (FILE, "\t%s\t ", TYPE_ASM_OP);           \
  84       assemble_name (FILE, NAME);                       \
  85       putc (',', FILE);                                 \
  86       fprintf (FILE, TYPE_OPERAND_FMT, "function");     \
  87       putc ('\n', FILE);                                \
  88       ASM_DECLARE_RESULT (FILE, DECL_RESULT (DECL));    \
  89       ASM_OUTPUT_LABEL(FILE, NAME);                     \
  90     }                                                   \
  91   while (0)
  92
  93 /* Write the extra assembler code needed to declare an object properly.  */
  94 #define ASM_DECLARE_OBJECT_NAME(FILE, NAME, DECL)               \
  95   do                                                            \
  96     {                                                           \
  97       fprintf (FILE, "\t%s\t ", TYPE_ASM_OP);                   \
  98       assemble_name (FILE, NAME);                               \
  99       putc (',', FILE);                                         \
 100       fprintf (FILE, TYPE_OPERAND_FMT, "object");               \
 101       putc ('\n', FILE);                                        \
 102       size_directive_output = 0;                                \
 103       if (!flag_inhibit_size_directive && DECL_SIZE (DECL))     \
 104         {                                                       \
 105           size_directive_output = 1;                            \
 106           fprintf (FILE, "\t%s\t ", SIZE_ASM_OP);               \
 107           assemble_name (FILE, NAME);                           \
 108           putc (',', FILE);                                     \
 109           fprintf (FILE, HOST_WIDE_INT_PRINT_DEC,               \
 110                    int_size_in_bytes (TREE_TYPE (DECL)));       \
 111           fputc ('\n', FILE);                                   \
 112         }                                                       \
 113       ASM_OUTPUT_LABEL(FILE, NAME);                             \
 114     }                                                           \
 115   while (0)
 116
 117 /* Output the size directive for a decl in rest_of_decl_compilation
 118    in the case where we did not do so before the initializer.
 119    Once we find the error_mark_node, we know that the value of
 120    size_directive_output was set
 121    by ASM_DECLARE_OBJECT_NAME when it was run for the same decl.  */
 122 #define ASM_FINISH_DECLARE_OBJECT(FILE, DECL, TOP_LEVEL, AT_END)        \
 123   do                                                                    \
 124     {                                                                   \
 125       const char * name = XSTR (XEXP (DECL_RTL (DECL), 0), 0);          \
 126       if (!flag_inhibit_size_directive && DECL_SIZE (DECL)              \
 127           && ! AT_END && TOP_LEVEL                                      \
 128           && DECL_INITIAL (DECL) == error_mark_node                     \
 129           && !size_directive_output)                                    \
 130         {                                                               \
 131           size_directive_output = 1;                                    \
 132           fprintf (FILE, "\t%s\t ", SIZE_ASM_OP);                       \
 133           assemble_name (FILE, name);                                   \
 134           putc (',', FILE);                                             \
 135           fprintf (FILE, HOST_WIDE_INT_PRINT_DEC,                       \
 136                   int_size_in_bytes (TREE_TYPE (DECL)));                \
 137          fputc ('\n', FILE);                                            \
 138         }                                                               \
 139     }                                                                   \
 140   while (0)
 141
 142 /* This is how to declare the size of a function.  */
 143 #define ASM_DECLARE_FUNCTION_SIZE(FILE, FNAME, DECL)            \
 144   do                                                            \
 145     {                                                           \
 146       ARM_DECLARE_FUNCTION_SIZE (FILE, FNAME, DECL);            \
 147       if (!flag_inhibit_size_directive)                         \
 148         {                                                       \
 149           char label[256];                                      \
 150           static int labelno;                                   \
 151           labelno ++;                                           \
 152           ASM_GENERATE_INTERNAL_LABEL (label, "Lfe", labelno);  \
 153           ASM_OUTPUT_INTERNAL_LABEL (FILE, "Lfe", labelno);     \
 154           fprintf (FILE, "\t%s\t ", SIZE_ASM_OP);               \
 155           assemble_name (FILE, (FNAME));                        \
 156           fprintf (FILE, ",");                                  \
 157           assemble_name (FILE, label);                          \
 158           fprintf (FILE, "-");                                  \
 159           assemble_name (FILE, (FNAME));                        \
 160           putc ('\n', FILE);                                    \
 161         }                                                       \
 162     }                                                           \
 163   while (0)
 164
 165 /* Define this macro if jump tables (for `tablejump' insns) should be
 166    output in the text section, along with the assembler instructions.
 167    Otherwise, the readonly data section is used.  */
 168 #define JUMP_TABLES_IN_TEXT_SECTION 1
 169
 170 #ifndef LINK_SPEC
 171 #define LINK_SPEC "%{mbig-endian:-EB} -X"
 172 #endif
 173
 174 /* Run-time Target Specification.  */
 175 #ifndef TARGET_VERSION
 176 #define TARGET_VERSION fputs (" (ARM/elf)", stderr)
 177 #endif
 178
 179 #ifndef TARGET_DEFAULT
 180 #define TARGET_DEFAULT (ARM_FLAG_SOFT_FLOAT | ARM_FLAG_APCS_32 | ARM_FLAG_APCS_FRAME)
 181 #endif
 182
 183 #ifndef MULTILIB_DEFAULTS
 184 #define MULTILIB_DEFAULTS \
 185   { "marm", "mlittle-endian", "msoft-float", "mapcs-32", "mno-thumb-interwork", "fno-leading-underscore" }
 186 #endif
 187
 188 /* A C expression whose value is nonzero if IDENTIFIER with arguments ARGS
 189    is a valid machine specific attribute for DECL.
 190    The attributes in ATTRIBUTES have previously been assigned to DECL.  */
 191 #define VALID_MACHINE_DECL_ATTRIBUTE(DECL, ATTRIBUTES, IDENTIFIER, ARGS) \
 192   arm_valid_machine_decl_attribute (DECL, IDENTIFIER, ARGS)
 193 \f
 194
 195 /* A C statement to output assembler commands which will identify the
 196    object file as having been compiled with GNU CC (or another GNU
 197    compiler).  */
 198 /* Define this to NULL so we don't get anything.
 199    We have ASM_IDENTIFY_LANGUAGE.
 200    Also, when using stabs, gcc2_compiled must be a stabs entry, not an
 201    ordinary symbol, or gdb won't see it.  The stabs entry must be
 202    before the N_SO in order for gdb to find it.  */
 203 #ifndef ASM_IDENTIFY_GCC
 204 #define ASM_IDENTIFY_GCC(STREAM)                                \
 205   fprintf (STREAM, "%sgcc2_compiled.:\n", LOCAL_LABEL_PREFIX )
 206 #endif
 207
 208 /* This outputs a lot of .req's to define alias for various registers.
 209    Let's try to avoid this.  */
 210 #ifndef ASM_FILE_START
 211 #define ASM_FILE_START(STREAM)                                  \
 212   do                                                            \
 213     {                                                           \
 214       fprintf (STREAM, "%s Generated by gcc %s for ARM/elf\n",  \
 215                ASM_COMMENT_START, version_string);              \
 216       output_file_directive (STREAM, main_input_filename);      \
 217       fprintf (STREAM, ASM_APP_OFF);                            \
 218     }                                                           \
 219   while (0)
 220 #endif
 221
 222 /* Output an internal label definition.  */
 223 #ifndef ASM_OUTPUT_INTERNAL_LABEL
 224 #define ASM_OUTPUT_INTERNAL_LABEL(STREAM, PREFIX, NUM)          \
 225   do                                                            \
 226     {                                                           \
 227       char * s = (char *) alloca (40 + strlen (PREFIX));        \
 228       extern int arm_target_label, arm_ccfsm_state;             \
 229       extern rtx arm_target_insn;                               \
 230                                                                 \
 231       if (arm_ccfsm_state == 3 && arm_target_label == (NUM)     \
 232         && !strcmp (PREFIX, "L"))                               \
 233         {                                                       \
 234           arm_ccfsm_state = 0;                                  \
 235           arm_target_insn = NULL;                               \
 236         }                                                       \
 237         ASM_GENERATE_INTERNAL_LABEL (s, (PREFIX), (NUM));       \
 238         ASM_OUTPUT_LABEL (STREAM, s);                           \
 239     }                                                           \
 240   while (0)
 241 #endif
 242 \f
 243 /* Support the ctors/dtors and other sections.  */
 244
 245 /* Define the pseudo-ops used to switch to the .ctors and .dtors sections.
 246
 247    Note that we want to give these sections the SHF_WRITE attribute
 248    because these sections will actually contain data (i.e. tables of
 249    addresses of functions in the current root executable or shared library
 250    file) and, in the case of a shared library, the relocatable addresses
 251    will have to be properly resolved/relocated (and then written into) by
 252    the dynamic linker when it actually attaches the given shared library
 253    to the executing process.  (Note that on SVR4, you may wish to use the
 254    `-z text' option to the ELF linker, when building a shared library, as
 255    an additional check that you are doing everything right.  But if you do
 256    use the `-z text' option when building a shared library, you will get
 257    errors unless the .ctors and .dtors sections are marked as writable
 258    via the SHF_WRITE attribute.)  */
 259 #ifndef CTORS_SECTION_ASM_OP
 260 #define CTORS_SECTION_ASM_OP    "\t.section\t.ctors,\"aw\""
 261 #endif
 262
 263 #ifndef DTORS_SECTION_ASM_OP
 264 #define DTORS_SECTION_ASM_OP    "\t.section\t.dtors,\"aw\""
 265 #endif
 266
 267 /* A list of other sections which the compiler might be "in" at any
 268    given time.  */
 269 #ifndef SUBTARGET_EXTRA_SECTIONS
 270 #define SUBTARGET_EXTRA_SECTIONS
 271 #endif
 272
 273 #ifndef EXTRA_SECTIONS
 274 #define EXTRA_SECTIONS SUBTARGET_EXTRA_SECTIONS in_ctors, in_dtors
 275 #endif
 276
 277 /* A list of extra section function definitions.  */
 278 #ifndef SUBTARGET_EXTRA_SECTION_FUNCTIONS
 279 #define SUBTARGET_EXTRA_SECTION_FUNCTIONS
 280 #endif
 281
 282 #ifndef EXTRA_SECTION_FUNCTIONS
 283 #define EXTRA_SECTION_FUNCTIONS                 \
 284   SUBTARGET_EXTRA_SECTION_FUNCTIONS             \
 285   CTORS_SECTION_FUNCTION                        \
 286   DTORS_SECTION_FUNCTION
 287 #endif
 288
 289 #ifndef CTORS_SECTION_FUNCTION
 290 #define CTORS_SECTION_FUNCTION                                  \
 291 void                                                            \
 292 ctors_section ()                                                \
 293 {                                                               \
 294   if (in_section != in_ctors)                                   \
 295     {                                                           \
 296       fprintf (asm_out_file, "%s\n", CTORS_SECTION_ASM_OP);     \
 297       in_section = in_ctors;                                    \
 298     }                                                           \
 299 }
 300 #endif
 301
 302 #ifndef DTORS_SECTION_FUNCTION
 303 #define DTORS_SECTION_FUNCTION                                  \
 304 void                                                            \
 305 dtors_section ()                                                \
 306 {                                                               \
 307   if (in_section != in_dtors)                                   \
 308     {                                                           \
 309       fprintf (asm_out_file, "%s\n", DTORS_SECTION_ASM_OP);     \
 310       in_section = in_dtors;                                    \
 311     }                                                           \
 312 }
 313 #endif
 314
 315 /* A C statement to output something to the assembler file to switch to
 316    section NAME for object DECL which is either a FUNCTION_DECL, a VAR_DECL
 317    or NULL_TREE.  */
 318 #undef  ASM_OUTPUT_SECTION_NAME
 319 #define ASM_OUTPUT_SECTION_NAME(STREAM, DECL, NAME, RELOC)              \
 320   do                                                                    \
 321     {                                                                   \
 322       if ((DECL) && TREE_CODE (DECL) == FUNCTION_DECL)                  \
 323         fprintf (STREAM, "\t.section %s,\"ax\",%%progbits\n", NAME);    \
 324       else if ((DECL) && DECL_READONLY_SECTION (DECL, RELOC))           \
 325         fprintf (STREAM, "\t.section %s,\"a\"\n", NAME);                \
 326       else if (! strncmp (NAME, ".bss", 4))                             \
 327         fprintf (STREAM, "\t.section %s,\"aw\",%%nobits\n", NAME);      \
 328       else                                                              \
 329         fprintf (STREAM, "\t.section %s,\"aw\"\n", NAME);               \
 330     }                                                                   \
 331   while (0)
 332 \f
 333 /* Support the ctors/dtors sections for g++.  */
 334 #ifndef INT_ASM_OP
 335 #define INT_ASM_OP      ".word"
 336 #endif
 337
 338 /* A C statement (sans semicolon) to output an element in the table of
 339    global constructors.  */
 340 #ifndef ASM_OUTPUT_CONSTRUCTOR
 341 #define ASM_OUTPUT_CONSTRUCTOR(STREAM, NAME)    \
 342   do                                            \
 343     {                                           \
 344       ctors_section ();                         \
 345       fprintf (STREAM, "\t%s\t ", INT_ASM_OP);  \
 346       assemble_name (STREAM, NAME);             \
 347       fprintf (STREAM, "\n");                   \
 348     }                                           \
 349   while (0)
 350 #endif
 351
 352 /* A C statement (sans semicolon) to output an element in the table of
 353    global destructors.  */
 354 #ifndef ASM_OUTPUT_DESTRUCTOR
 355 #define ASM_OUTPUT_DESTRUCTOR(STREAM, NAME)     \
 356   do                                            \
 357     {                                           \
 358       dtors_section ();                         \
 359       fprintf (STREAM, "\t%s\t ", INT_ASM_OP);  \
 360       assemble_name (STREAM, NAME);             \
 361       fprintf (STREAM, "\n");                   \
 362     }                                           \
 363   while (0)
 364 #endif
 365
 366 /* This is how we tell the assembler that a symbol is weak.  */
 367
 368 #define ASM_WEAKEN_LABEL(FILE, NAME)            \
 369   do                                            \
 370     {                                           \
 371       fputs ("\t.weak\t", FILE);                \
 372       assemble_name (FILE, NAME);               \
 373       fputc ('\n', FILE);                       \
 374     }                                           \
 375   while (0)
 376
 377 /* For PIC code we need to explicitly specify (PLT) and (GOT) relocs.  */
 378 #define NEED_PLT_RELOC  flag_pic
 379 #define NEED_GOT_RELOC  flag_pic
 380
 381 /* The ELF assembler handles GOT addressing differently to NetBSD.  */
 382 #define GOT_PCREL       0
 383
 384 /* Biggest alignment supported by the object file format of this
 385    machine.  Use this macro to limit the alignment which can be
 386    specified using the `__attribute__ ((aligned (N)))' construct.  If
 387    not defined, the default value is `BIGGEST_ALIGNMENT'.  */
 388 #define MAX_OFILE_ALIGNMENT (32768 * 8)
 389
 390 /* Align output to a power of two.  Note ".align 0" is redundant,
 391    and also GAS will treat it as ".align 2" which we do not want.  */
 392 #define ASM_OUTPUT_ALIGN(STREAM, POWER)                 \
 393   do                                                    \
 394     {                                                   \
 395       if ((POWER) > 0)                                  \
 396         fprintf (STREAM, "\t.align\t%d\n", POWER);      \
 397     }                                                   \
 398   while (0)
 399
 400 #include "aout.h"