gcc/config/arm/elf.h

   1 /* Definitions of target machine for GNU compiler,
   2    for ARM with ELF obj format.
   3    Copyright (C) 1995, 1996, 1997, 1998, 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 /* The following macro defines the format used to output the second
  40    operand of the .type assembler directive.  Different svr4 assemblers
  41    expect various different forms for this operand.  The one given here
  42    is just a default.  You may need to override it in your machine-
  43    specific tm.h file (depending upon the particulars of your assembler).  */
  44 #define TYPE_OPERAND_FMT        "%s"
  45
  46 /* Write the extra assembler code needed to declare a function's result.
  47    Most svr4 assemblers don't require any special declaration of the
  48    result value, but there are exceptions.  */
  49 #ifndef ASM_DECLARE_RESULT
  50 #define ASM_DECLARE_RESULT(FILE, RESULT)
  51 #endif
  52
  53 /* These macros generate the special .type and .size directives which
  54    are used to set the corresponding fields of the linker symbol table
  55    entries in an ELF object file under SVR4.  These macros also output
  56    the starting labels for the relevant functions/objects.  */
  57 #define TYPE_ASM_OP     ".type"
  58 #define SIZE_ASM_OP     ".size"
  59
  60 /* Write the extra assembler code needed to declare a function properly.
  61    Some svr4 assemblers need to also have something extra said about the
  62    function's return value.  We allow for that here.  */
  63 #define ASM_DECLARE_FUNCTION_NAME(FILE, NAME, DECL)     \
  64   do                                                    \
  65     {                                                   \
  66       ARM_DECLARE_FUNCTION_NAME (FILE, NAME, DECL);     \
  67       fprintf (FILE, "\t%s\t ", TYPE_ASM_OP);           \
  68       assemble_name (FILE, NAME);                       \
  69       putc (',', FILE);                                 \
  70       fprintf (FILE, TYPE_OPERAND_FMT, "function");     \
  71       putc ('\n', FILE);                                \
  72       ASM_DECLARE_RESULT (FILE, DECL_RESULT (DECL));    \
  73       ASM_OUTPUT_LABEL(FILE, NAME);                     \
  74     }                                                   \
  75   while (0)
  76
  77 /* Write the extra assembler code needed to declare an object properly.  */
  78 #define ASM_DECLARE_OBJECT_NAME(FILE, NAME, DECL)               \
  79   do                                                            \
  80     {                                                           \
  81       fprintf (FILE, "\t%s\t ", TYPE_ASM_OP);                   \
  82       assemble_name (FILE, NAME);                               \
  83       putc (',', FILE);                                         \
  84       fprintf (FILE, TYPE_OPERAND_FMT, "object");               \
  85       putc ('\n', FILE);                                        \
  86       size_directive_output = 0;                                \
  87       if (!flag_inhibit_size_directive && DECL_SIZE (DECL))     \
  88         {                                                       \
  89           size_directive_output = 1;                            \
  90           fprintf (FILE, "\t%s\t ", SIZE_ASM_OP);               \
  91           assemble_name (FILE, NAME);                           \
  92           putc (',', FILE);                                     \
  93           fprintf (FILE, HOST_WIDE_INT_PRINT_DEC,               \
  94                    int_size_in_bytes (TREE_TYPE (DECL)));       \
  95           fputc ('\n', FILE);                                   \
  96         }                                                       \
  97       ASM_OUTPUT_LABEL(FILE, NAME);                             \
  98     }                                                           \
  99   while (0)
 100
 101 /* Output the size directive for a decl in rest_of_decl_compilation
 102    in the case where we did not do so before the initializer.
 103    Once we find the error_mark_node, we know that the value of
 104    size_directive_output was set
 105    by ASM_DECLARE_OBJECT_NAME when it was run for the same decl.  */
 106 #define ASM_FINISH_DECLARE_OBJECT(FILE, DECL, TOP_LEVEL, AT_END)        \
 107   do                                                                    \
 108     {                                                                   \
 109       char * name = XSTR (XEXP (DECL_RTL (DECL), 0), 0);                \
 110       if (!flag_inhibit_size_directive && DECL_SIZE (DECL)              \
 111           && ! AT_END && TOP_LEVEL                                      \
 112           && DECL_INITIAL (DECL) == error_mark_node                     \
 113           && !size_directive_output)                                    \
 114         {                                                               \
 115           size_directive_output = 1;                                    \
 116           fprintf (FILE, "\t%s\t ", SIZE_ASM_OP);                       \
 117           assemble_name (FILE, name);                                   \
 118           putc (',', FILE);                                             \
 119           fprintf (FILE, HOST_WIDE_INT_PRINT_DEC,                       \
 120                   int_size_in_bytes (TREE_TYPE (DECL)));                \
 121          fputc ('\n', FILE);                                            \
 122         }                                                               \
 123     }                                                                   \
 124   while (0)
 125
 126 /* This is how to declare the size of a function.  */
 127 #define ASM_DECLARE_FUNCTION_SIZE(FILE, FNAME, DECL)            \
 128   do                                                            \
 129     {                                                           \
 130       if (!flag_inhibit_size_directive)                         \
 131         {                                                       \
 132           char label[256];                                      \
 133           static int labelno;                                   \
 134           labelno ++;                                           \
 135           ASM_GENERATE_INTERNAL_LABEL (label, "Lfe", labelno);  \
 136           ASM_OUTPUT_INTERNAL_LABEL (FILE, "Lfe", labelno);     \
 137           fprintf (FILE, "\t%s\t ", SIZE_ASM_OP);               \
 138           assemble_name (FILE, (FNAME));                        \
 139           fprintf (FILE, ",");                                  \
 140           assemble_name (FILE, label);                          \
 141           fprintf (FILE, "-");                                  \
 142           assemble_name (FILE, (FNAME));                        \
 143           putc ('\n', FILE);                                    \
 144         }                                                       \
 145     }                                                           \
 146   while (0)
 147
 148 /* Define this macro if jump tables (for `tablejump' insns) should be
 149    output in the text section, along with the assembler instructions.
 150    Otherwise, the readonly data section is used.  */
 151 #define JUMP_TABLES_IN_TEXT_SECTION 1
 152
 153 #ifndef ASM_SPEC
 154 #define ASM_SPEC "%{mbig-endian:-EB} %{mcpu=*:-m%*} %{march=*:-m%*} \
 155  %{mapcs-*:-mapcs-%*} %{mthumb-interwork:-mthumb-interwork} %{mapcs-float:mfloat}"
 156 #endif
 157
 158 #ifndef LINK_SPEC
 159 #define LINK_SPEC "%{mbig-endian:-EB} -X"
 160 #endif
 161
 162 /* Run-time Target Specification.  */
 163 #ifndef TARGET_VERSION
 164 #define TARGET_VERSION fputs (" (ARM/elf)", stderr)
 165 #endif
 166
 167 #ifndef TARGET_DEFAULT
 168 #define TARGET_DEFAULT (ARM_FLAG_SOFT_FLOAT | ARM_FLAG_APCS_32)
 169 #endif
 170
 171 #ifndef MULTILIB_DEFAULTS
 172 #define MULTILIB_DEFAULTS { "mlittle-endian", "msoft-float", "mapcs-32", "mno-thumb-interwork" }
 173 #endif
 174
 175 /* A C expression whose value is nonzero if IDENTIFIER with arguments ARGS
 176    is a valid machine specific attribute for DECL.
 177    The attributes in ATTRIBUTES have previously been assigned to DECL.  */
 178 #define VALID_MACHINE_DECL_ATTRIBUTE(DECL, ATTRIBUTES, IDENTIFIER, ARGS) \
 179   arm_valid_machine_decl_attribute (DECL, IDENTIFIER, ARGS)
 180 \f
 181
 182 /* A C statement to output assembler commands which will identify the
 183    object file as having been compiled with GNU CC (or another GNU
 184    compiler).  */
 185 /* Define this to NULL so we don't get anything.
 186    We have ASM_IDENTIFY_LANGUAGE.
 187    Also, when using stabs, gcc2_compiled must be a stabs entry, not an
 188    ordinary symbol, or gdb won't see it.  The stabs entry must be
 189    before the N_SO in order for gdb to find it.  */
 190 #ifndef ASM_IDENTIFY_GCC
 191 #define ASM_IDENTIFY_GCC(STREAM)                                \
 192   fprintf (STREAM, "%sgcc2_compiled.:\n", LOCAL_LABEL_PREFIX )
 193 #endif
 194
 195 /* This outputs a lot of .req's to define alias for various registers.
 196    Let's try to avoid this.  */
 197 #ifndef ASM_FILE_START
 198 #define ASM_FILE_START(STREAM)                                  \
 199   do                                                            \
 200     {                                                           \
 201       fprintf (STREAM, "%s Generated by gcc %s for ARM/elf\n",  \
 202                ASM_COMMENT_START, version_string);              \
 203       output_file_directive (STREAM, main_input_filename);      \
 204       fprintf (STREAM, ASM_APP_OFF);                            \
 205     }                                                           \
 206   while (0)
 207 #endif
 208
 209 /* Output an internal label definition.  */
 210 #ifndef ASM_OUTPUT_INTERNAL_LABEL
 211 #define ASM_OUTPUT_INTERNAL_LABEL(STREAM, PREFIX, NUM)          \
 212   do                                                            \
 213     {                                                           \
 214       char * s = (char *) alloca (40 + strlen (PREFIX));        \
 215       extern int arm_target_label, arm_ccfsm_state;             \
 216       extern rtx arm_target_insn;                               \
 217                                                                 \
 218       if (arm_ccfsm_state == 3 && arm_target_label == (NUM)     \
 219         && !strcmp (PREFIX, "L"))                               \
 220         {                                                       \
 221           arm_ccfsm_state = 0;                                  \
 222           arm_target_insn = NULL;                               \
 223         }                                                       \
 224         ASM_GENERATE_INTERNAL_LABEL (s, (PREFIX), (NUM));       \
 225         ASM_OUTPUT_LABEL (STREAM, s);                           \
 226     }                                                           \
 227   while (0)
 228 #endif
 229 \f
 230 /* Support the ctors/dtors and other sections.  */
 231
 232 /* Define the pseudo-ops used to switch to the .ctors and .dtors sections.
 233
 234    Note that we want to give these sections the SHF_WRITE attribute
 235    because these sections will actually contain data (i.e. tables of
 236    addresses of functions in the current root executable or shared library
 237    file) and, in the case of a shared library, the relocatable addresses
 238    will have to be properly resolved/relocated (and then written into) by
 239    the dynamic linker when it actually attaches the given shared library
 240    to the executing process.  (Note that on SVR4, you may wish to use the
 241    `-z text' option to the ELF linker, when building a shared library, as
 242    an additional check that you are doing everything right.  But if you do
 243    use the `-z text' option when building a shared library, you will get
 244    errors unless the .ctors and .dtors sections are marked as writable
 245    via the SHF_WRITE attribute.)  */
 246 #ifndef CTORS_SECTION_ASM_OP
 247 #define CTORS_SECTION_ASM_OP    "\t.section\t.ctors,\"aw\""
 248 #endif
 249
 250 #ifndef DTORS_SECTION_ASM_OP
 251 #define DTORS_SECTION_ASM_OP    "\t.section\t.dtors,\"aw\""
 252 #endif
 253
 254 /* A list of other sections which the compiler might be "in" at any
 255    given time.  */
 256 #ifndef SUBTARGET_EXTRA_SECTIONS
 257 #define SUBTARGET_EXTRA_SECTIONS
 258 #endif
 259
 260 #ifndef EXTRA_SECTIONS
 261 #define EXTRA_SECTIONS SUBTARGET_EXTRA_SECTIONS in_ctors, in_dtors
 262 #endif
 263
 264 /* A list of extra section function definitions.  */
 265 #ifndef SUBTARGET_EXTRA_SECTION_FUNCTIONS
 266 #define SUBTARGET_EXTRA_SECTION_FUNCTIONS
 267 #endif
 268
 269 #ifndef EXTRA_SECTION_FUNCTIONS
 270 #define EXTRA_SECTION_FUNCTIONS                 \
 271   SUBTARGET_EXTRA_SECTION_FUNCTIONS             \
 272   CTORS_SECTION_FUNCTION                        \
 273   DTORS_SECTION_FUNCTION
 274 #endif
 275
 276 #ifndef CTORS_SECTION_FUNCTION
 277 #define CTORS_SECTION_FUNCTION                                          \
 278 void                                                                    \
 279 ctors_section ()                                                        \
 280 {                                                                       \
 281   if (in_section != in_ctors)                                           \
 282     {                                                                   \
 283       fprintf (asm_out_file, "%s\n", CTORS_SECTION_ASM_OP);             \
 284       in_section = in_ctors;                                            \
 285     }                                                                   \
 286 }
 287 #endif
 288
 289 #ifndef DTORS_SECTION_FUNCTION
 290 #define DTORS_SECTION_FUNCTION                                          \
 291 void                                                                    \
 292 dtors_section ()                                                        \
 293 {                                                                       \
 294   if (in_section != in_dtors)                                           \
 295     {                                                                   \
 296       fprintf (asm_out_file, "%s\n", DTORS_SECTION_ASM_OP);             \
 297       in_section = in_dtors;                                            \
 298     }                                                                   \
 299 }
 300 #endif
 301 \f
 302 /* Support the ctors/dtors sections for g++.  */
 303 #ifndef INT_ASM_OP
 304 #define INT_ASM_OP      ".word"
 305 #endif
 306
 307 /* A C statement (sans semicolon) to output an element in the table of
 308    global constructors.  */
 309 #ifndef ASM_OUTPUT_CONSTRUCTOR
 310 #define ASM_OUTPUT_CONSTRUCTOR(STREAM, NAME)    \
 311   do                                            \
 312     {                                           \
 313       ctors_section ();                         \
 314       fprintf (STREAM, "\t%s\t ", INT_ASM_OP);  \
 315       assemble_name (STREAM, NAME);             \
 316       fprintf (STREAM, "\n");                   \
 317     }                                           \
 318   while (0)
 319 #endif
 320
 321 /* A C statement (sans semicolon) to output an element in the table of
 322    global destructors.  */
 323 #ifndef ASM_OUTPUT_DESTRUCTOR
 324 #define ASM_OUTPUT_DESTRUCTOR(STREAM, NAME)     \
 325   do                                            \
 326     {                                           \
 327       dtors_section ();                         \
 328       fprintf (STREAM, "\t%s\t ", INT_ASM_OP);  \
 329       assemble_name (STREAM, NAME);             \
 330       fprintf (STREAM, "\n");                   \
 331     }                                           \
 332   while (0)
 333 #endif
 334
 335 /* This is how we tell the assembler that a symbol is weak.  */
 336
 337 #define ASM_WEAKEN_LABEL(FILE, NAME)            \
 338   do                                            \
 339     {                                           \
 340       fputs ("\t.weak\t", FILE);                \
 341       assemble_name (FILE, NAME);               \
 342       fputc ('\n', FILE);                       \
 343     }                                           \
 344   while (0)
 345
 346 /* For PIC code we need to explicitly specify (PLT) and (GOT) relocs.  */
 347 #define NEED_PLT_RELOC  flag_pic
 348 #define NEED_GOT_RELOC  flag_pic
 349
 350 /* The ELF assembler handles GOT addressing differently to NetBSD.  */
 351 #define GOT_PCREL       0
 352
 353 /* Biggest alignment supported by the object file format of this
 354    machine.  Use this macro to limit the alignment which can be
 355    specified using the `__attribute__ ((aligned (N)))' construct.  If
 356    not defined, the default value is `BIGGEST_ALIGNMENT'.  */
 357 #define MAX_OFILE_ALIGNMENT (32768 * 8)
 358
 359 /* Align output to a power of two.  Note ".align 0" is redundant,
 360    and also GAS will treat it as ".align 2" which we do not want.  */
 361 #define ASM_OUTPUT_ALIGN(STREAM, POWER)                 \
 362   do                                                    \
 363     {                                                   \
 364       if ((POWER) > 0)                                  \
 365         fprintf (STREAM, "\t.align\t%d\n", POWER);      \
 366     }                                                   \
 367   while (0)
 368
 369 #include "arm/aout.h"