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       ARM_DECLARE_FUNCTION_SIZE (FILE, FNAME, DECL);            \
 131       if (!flag_inhibit_size_directive)                         \
 132         {                                                       \
 133           char label[256];                                      \
 134           static int labelno;                                   \
 135           labelno ++;                                           \
 136           ASM_GENERATE_INTERNAL_LABEL (label, "Lfe", labelno);  \
 137           ASM_OUTPUT_INTERNAL_LABEL (FILE, "Lfe", labelno);     \
 138           fprintf (FILE, "\t%s\t ", SIZE_ASM_OP);               \
 139           assemble_name (FILE, (FNAME));                        \
 140           fprintf (FILE, ",");                                  \
 141           assemble_name (FILE, label);                          \
 142           fprintf (FILE, "-");                                  \
 143           assemble_name (FILE, (FNAME));                        \
 144           putc ('\n', FILE);                                    \
 145         }                                                       \
 146     }                                                           \
 147   while (0)
 148
 149 /* Define this macro if jump tables (for `tablejump' insns) should be
 150    output in the text section, along with the assembler instructions.
 151    Otherwise, the readonly data section is used.  */
 152 #define JUMP_TABLES_IN_TEXT_SECTION 1
 153
 154 #ifndef ASM_SPEC
 155 #define ASM_SPEC "%{mbig-endian:-EB} %{mcpu=*:-m%*} %{march=*:-m%*} \
 156  %{mapcs-*:-mapcs-%*} %{mthumb-interwork:-mthumb-interwork} %{mapcs-float:mfloat}"
 157 #endif
 158
 159 #ifndef LINK_SPEC
 160 #define LINK_SPEC "%{mbig-endian:-EB} -X"
 161 #endif
 162
 163 /* Run-time Target Specification.  */
 164 #ifndef TARGET_VERSION
 165 #define TARGET_VERSION fputs (" (ARM/elf)", stderr)
 166 #endif
 167
 168 #ifndef TARGET_DEFAULT
 169 #define TARGET_DEFAULT (ARM_FLAG_SOFT_FLOAT | ARM_FLAG_APCS_32)
 170 #endif
 171
 172 #ifndef MULTILIB_DEFAULTS
 173 #define MULTILIB_DEFAULTS { "mlittle-endian", "msoft-float", "mapcs-32", "mno-thumb-interwork" }
 174 #endif
 175
 176 /* A C expression whose value is nonzero if IDENTIFIER with arguments ARGS
 177    is a valid machine specific attribute for DECL.
 178    The attributes in ATTRIBUTES have previously been assigned to DECL.  */
 179 #define VALID_MACHINE_DECL_ATTRIBUTE(DECL, ATTRIBUTES, IDENTIFIER, ARGS) \
 180   arm_valid_machine_decl_attribute (DECL, IDENTIFIER, ARGS)
 181 \f
 182
 183 /* A C statement to output assembler commands which will identify the
 184    object file as having been compiled with GNU CC (or another GNU
 185    compiler).  */
 186 /* Define this to NULL so we don't get anything.
 187    We have ASM_IDENTIFY_LANGUAGE.
 188    Also, when using stabs, gcc2_compiled must be a stabs entry, not an
 189    ordinary symbol, or gdb won't see it.  The stabs entry must be
 190    before the N_SO in order for gdb to find it.  */
 191 #ifndef ASM_IDENTIFY_GCC
 192 #define ASM_IDENTIFY_GCC(STREAM)                                \
 193   fprintf (STREAM, "%sgcc2_compiled.:\n", LOCAL_LABEL_PREFIX )
 194 #endif
 195
 196 /* This outputs a lot of .req's to define alias for various registers.
 197    Let's try to avoid this.  */
 198 #ifndef ASM_FILE_START
 199 #define ASM_FILE_START(STREAM)                                  \
 200   do                                                            \
 201     {                                                           \
 202       fprintf (STREAM, "%s Generated by gcc %s for ARM/elf\n",  \
 203                ASM_COMMENT_START, version_string);              \
 204       output_file_directive (STREAM, main_input_filename);      \
 205       fprintf (STREAM, ASM_APP_OFF);                            \
 206     }                                                           \
 207   while (0)
 208 #endif
 209
 210 /* Output an internal label definition.  */
 211 #ifndef ASM_OUTPUT_INTERNAL_LABEL
 212 #define ASM_OUTPUT_INTERNAL_LABEL(STREAM, PREFIX, NUM)          \
 213   do                                                            \
 214     {                                                           \
 215       char * s = (char *) alloca (40 + strlen (PREFIX));        \
 216       extern int arm_target_label, arm_ccfsm_state;             \
 217       extern rtx arm_target_insn;                               \
 218                                                                 \
 219       if (arm_ccfsm_state == 3 && arm_target_label == (NUM)     \
 220         && !strcmp (PREFIX, "L"))                               \
 221         {                                                       \
 222           arm_ccfsm_state = 0;                                  \
 223           arm_target_insn = NULL;                               \
 224         }                                                       \
 225         ASM_GENERATE_INTERNAL_LABEL (s, (PREFIX), (NUM));       \
 226         ASM_OUTPUT_LABEL (STREAM, s);                           \
 227     }                                                           \
 228   while (0)
 229 #endif
 230 \f
 231 /* Support the ctors/dtors and other sections.  */
 232
 233 /* Define the pseudo-ops used to switch to the .ctors and .dtors sections.
 234
 235    Note that we want to give these sections the SHF_WRITE attribute
 236    because these sections will actually contain data (i.e. tables of
 237    addresses of functions in the current root executable or shared library
 238    file) and, in the case of a shared library, the relocatable addresses
 239    will have to be properly resolved/relocated (and then written into) by
 240    the dynamic linker when it actually attaches the given shared library
 241    to the executing process.  (Note that on SVR4, you may wish to use the
 242    `-z text' option to the ELF linker, when building a shared library, as
 243    an additional check that you are doing everything right.  But if you do
 244    use the `-z text' option when building a shared library, you will get
 245    errors unless the .ctors and .dtors sections are marked as writable
 246    via the SHF_WRITE attribute.)  */
 247 #ifndef CTORS_SECTION_ASM_OP
 248 #define CTORS_SECTION_ASM_OP    "\t.section\t.ctors,\"aw\""
 249 #endif
 250
 251 #ifndef DTORS_SECTION_ASM_OP
 252 #define DTORS_SECTION_ASM_OP    "\t.section\t.dtors,\"aw\""
 253 #endif
 254
 255 /* A list of other sections which the compiler might be "in" at any
 256    given time.  */
 257 #ifndef SUBTARGET_EXTRA_SECTIONS
 258 #define SUBTARGET_EXTRA_SECTIONS
 259 #endif
 260
 261 #ifndef EXTRA_SECTIONS
 262 #define EXTRA_SECTIONS SUBTARGET_EXTRA_SECTIONS in_ctors, in_dtors
 263 #endif
 264
 265 /* A list of extra section function definitions.  */
 266 #ifndef SUBTARGET_EXTRA_SECTION_FUNCTIONS
 267 #define SUBTARGET_EXTRA_SECTION_FUNCTIONS
 268 #endif
 269
 270 #ifndef EXTRA_SECTION_FUNCTIONS
 271 #define EXTRA_SECTION_FUNCTIONS                 \
 272   SUBTARGET_EXTRA_SECTION_FUNCTIONS             \
 273   CTORS_SECTION_FUNCTION                        \
 274   DTORS_SECTION_FUNCTION
 275 #endif
 276
 277 #ifndef CTORS_SECTION_FUNCTION
 278 #define CTORS_SECTION_FUNCTION                                          \
 279 void                                                                    \
 280 ctors_section ()                                                        \
 281 {                                                                       \
 282   if (in_section != in_ctors)                                           \
 283     {                                                                   \
 284       fprintf (asm_out_file, "%s\n", CTORS_SECTION_ASM_OP);             \
 285       in_section = in_ctors;                                            \
 286     }                                                                   \
 287 }
 288 #endif
 289
 290 #ifndef DTORS_SECTION_FUNCTION
 291 #define DTORS_SECTION_FUNCTION                                          \
 292 void                                                                    \
 293 dtors_section ()                                                        \
 294 {                                                                       \
 295   if (in_section != in_dtors)                                           \
 296     {                                                                   \
 297       fprintf (asm_out_file, "%s\n", DTORS_SECTION_ASM_OP);             \
 298       in_section = in_dtors;                                            \
 299     }                                                                   \
 300 }
 301 #endif
 302 \f
 303 /* Support the ctors/dtors sections for g++.  */
 304 #ifndef INT_ASM_OP
 305 #define INT_ASM_OP      ".word"
 306 #endif
 307
 308 /* A C statement (sans semicolon) to output an element in the table of
 309    global constructors.  */
 310 #ifndef ASM_OUTPUT_CONSTRUCTOR
 311 #define ASM_OUTPUT_CONSTRUCTOR(STREAM, NAME)    \
 312   do                                            \
 313     {                                           \
 314       ctors_section ();                         \
 315       fprintf (STREAM, "\t%s\t ", INT_ASM_OP);  \
 316       assemble_name (STREAM, NAME);             \
 317       fprintf (STREAM, "\n");                   \
 318     }                                           \
 319   while (0)
 320 #endif
 321
 322 /* A C statement (sans semicolon) to output an element in the table of
 323    global destructors.  */
 324 #ifndef ASM_OUTPUT_DESTRUCTOR
 325 #define ASM_OUTPUT_DESTRUCTOR(STREAM, NAME)     \
 326   do                                            \
 327     {                                           \
 328       dtors_section ();                         \
 329       fprintf (STREAM, "\t%s\t ", INT_ASM_OP);  \
 330       assemble_name (STREAM, NAME);             \
 331       fprintf (STREAM, "\n");                   \
 332     }                                           \
 333   while (0)
 334 #endif
 335
 336 /* This is how we tell the assembler that a symbol is weak.  */
 337
 338 #define ASM_WEAKEN_LABEL(FILE, NAME)            \
 339   do                                            \
 340     {                                           \
 341       fputs ("\t.weak\t", FILE);                \
 342       assemble_name (FILE, NAME);               \
 343       fputc ('\n', FILE);                       \
 344     }                                           \
 345   while (0)
 346
 347 /* For PIC code we need to explicitly specify (PLT) and (GOT) relocs.  */
 348 #define NEED_PLT_RELOC  flag_pic
 349 #define NEED_GOT_RELOC  flag_pic
 350
 351 /* The ELF assembler handles GOT addressing differently to NetBSD.  */
 352 #define GOT_PCREL       0
 353
 354 /* Biggest alignment supported by the object file format of this
 355    machine.  Use this macro to limit the alignment which can be
 356    specified using the `__attribute__ ((aligned (N)))' construct.  If
 357    not defined, the default value is `BIGGEST_ALIGNMENT'.  */
 358 #define MAX_OFILE_ALIGNMENT (32768 * 8)
 359
 360 /* Align output to a power of two.  Note ".align 0" is redundant,
 361    and also GAS will treat it as ".align 2" which we do not want.  */
 362 #define ASM_OUTPUT_ALIGN(STREAM, POWER)                 \
 363   do                                                    \
 364     {                                                   \
 365       if ((POWER) > 0)                                  \
 366         fprintf (STREAM, "\t.align\t%d\n", POWER);      \
 367     }                                                   \
 368   while (0)
 369
 370 #include "arm/aout.h"