elf.h

gcc-2.95.3 Linux下最常用的C编译器

/* Definitions of target machine for GNU compiler, for DEC Alpha w/ELF.
   Copyright (C) 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
   Contributed by Richard Henderson ([e-mail]).

This file is part of GNU CC.

GNU CC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU CC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.    */

#undef OBJECT_FORMAT_COFF
#undef EXTENDED_COFF
#define OBJECT_FORMAT_ELF

#define DBX_DEBUGGING_INFO
#define DWARF2_DEBUGGING_INFO

#undef PREFERRED_DEBUGGING_TYPE
#define PREFERRED_DEBUGGING_TYPE DBX_DEBUG

#undef ASM_FINAL_SPEC

#undef CC1_SPEC
#define CC1_SPEC  "%{G*}"

#undef ASM_SPEC
#define ASM_SPEC  "%{G*} %{relax:-relax} %{gdwarf*:-no-mdebug}"

#undef LINK_SPEC
#define LINK_SPEC "-m elf64alpha %{G*} %{relax:-relax}		\
  %{O*:-O3} %{!O*:-O1}						\
  %{shared:-shared}						\
  %{!shared:							\
    %{!static:							\
      %{rdynamic:-export-dynamic}				\
      %{!dynamic-linker:-dynamic-linker %(elf_dynamic_linker)}}	\
    %{static:-static}}"

/* Output at beginning of assembler file.  */
#undef ASM_FILE_START
#define ASM_FILE_START(FILE)					\
do {								\
  if (write_symbols != DWARF2_DEBUG)				\
    {								\
      alpha_write_verstamp (FILE);				\
      output_file_directive (FILE, main_input_filename);	\
    }								\
  fprintf (FILE, "\t.set noat\n");				\
  fprintf (FILE, "\t.set noreorder\n");				\
  if (TARGET_BWX | TARGET_MAX | TARGET_FIX | TARGET_CIX)	\
    {								\
      fprintf (FILE, "\t.arch %s\n",				\
               (alpha_cpu == PROCESSOR_EV6 ? "ev6"		\
                : TARGET_MAX ? "pca56" : "ev56"));		\
    }								\
} while (0)

extern void output_file_directive ();

/* Attach a special .ident directive to the end of the file to identify
   the version of GCC which compiled this code.  The format of the
   .ident string is patterned after the ones produced by native svr4
   C compilers.  */

#define IDENT_ASM_OP ".ident"

#ifdef IDENTIFY_WITH_IDENT
#define ASM_IDENTIFY_GCC(FILE) /* nothing */
#define ASM_IDENTIFY_LANGUAGE(FILE)			\
 fprintf(FILE, "\t%s \"GCC (%s) %s\"\n", IDENT_ASM_OP,	\
	 lang_identify(), version_string)
#else
#define ASM_FILE_END(FILE)					\
do {				 				\
     if (!flag_no_ident)					\
	fprintf ((FILE), "\t%s\t\"GCC: (GNU) %s\"\n",		\
		 IDENT_ASM_OP, version_string);			\
   } while (0)
#endif

/* Allow #sccs in preprocessor.  */
#define SCCS_DIRECTIVE

/* Output #ident as a .ident.  */
#define ASM_OUTPUT_IDENT(FILE, NAME) \
  fprintf (FILE, "\t%s\t\"%s\"\n", IDENT_ASM_OP, NAME);

/* This is how to allocate empty space in some section.  The .zero
   pseudo-op is used for this on most svr4 assemblers.  */

#define SKIP_ASM_OP	".zero"

#undef ASM_OUTPUT_SKIP
#define ASM_OUTPUT_SKIP(FILE,SIZE) \
  fprintf (FILE, "\t%s\t%u\n", SKIP_ASM_OP, (SIZE))

/* Output the label which precedes a jumptable.  Note that for all svr4
   systems where we actually generate jumptables (which is to say every
   svr4 target except i386, where we use casesi instead) we put the jump-
   tables into the .rodata section and since other stuff could have been
   put into the .rodata section prior to any given jumptable, we have to
   make sure that the location counter for the .rodata section gets pro-
   perly re-aligned prior to the actual beginning of the jump table.  */

#define ALIGN_ASM_OP ".align"

#ifndef ASM_OUTPUT_BEFORE_CASE_LABEL
#define ASM_OUTPUT_BEFORE_CASE_LABEL(FILE,PREFIX,NUM,TABLE) \
  ASM_OUTPUT_ALIGN ((FILE), 2);
#endif

#undef ASM_OUTPUT_CASE_LABEL
#define ASM_OUTPUT_CASE_LABEL(FILE,PREFIX,NUM,JUMPTABLE)		\
  do {									\
    ASM_OUTPUT_BEFORE_CASE_LABEL (FILE, PREFIX, NUM, JUMPTABLE)		\
    ASM_OUTPUT_INTERNAL_LABEL (FILE, PREFIX, NUM);			\
  } while (0)

/* The standard SVR4 assembler seems to require that certain builtin
   library routines (e.g. .udiv) be explicitly declared as .globl
   in each assembly file where they are referenced.  */

#define ASM_OUTPUT_EXTERNAL_LIBCALL(FILE, FUN)				\
  ASM_GLOBALIZE_LABEL (FILE, XSTR (FUN, 0))

/* This says how to output assembler code to declare an
   uninitialized external linkage data object.  Under SVR4,
   the linker seems to want the alignment of data objects
   to depend on their types.  We do exactly that here.  */

#define COMMON_ASM_OP	".comm"

#undef ASM_OUTPUT_ALIGNED_COMMON
#define ASM_OUTPUT_ALIGNED_COMMON(FILE, NAME, SIZE, ALIGN)		\
do {									\
  fprintf ((FILE), "\t%s\t", COMMON_ASM_OP);				\
  assemble_name ((FILE), (NAME));					\
  fprintf ((FILE), ",%u,%u\n", (SIZE), (ALIGN) / BITS_PER_UNIT);	\
} while (0)

/* This says how to output assembler code to declare an
   uninitialized internal linkage data object.  Under SVR4,
   the linker seems to want the alignment of data objects
   to depend on their types.  We do exactly that here.  */

#undef ASM_OUTPUT_ALIGNED_LOCAL
#define ASM_OUTPUT_ALIGNED_LOCAL(FILE, NAME, SIZE, ALIGN)		\
do {									\
  if ((SIZE) <= g_switch_value)						\
    sbss_section();							\
  else									\
    bss_section();							\
  fprintf (FILE, "\t%s\t ", TYPE_ASM_OP);				\
  assemble_name (FILE, NAME);						\
  putc (',', FILE);							\
  fprintf (FILE, TYPE_OPERAND_FMT, "object");				\
  putc ('\n', FILE);							\
  if (!flag_inhibit_size_directive)					\
    {									\
      fprintf (FILE, "\t%s\t ", SIZE_ASM_OP);				\
      assemble_name (FILE, NAME);					\
      fprintf (FILE, ",%d\n", (SIZE));					\
    }									\
  ASM_OUTPUT_ALIGN ((FILE), exact_log2((ALIGN) / BITS_PER_UNIT));	\
  ASM_OUTPUT_LABEL(FILE, NAME);						\
  ASM_OUTPUT_SKIP((FILE), (SIZE));					\
} while (0)

/* This is the pseudo-op used to generate a 64-bit word of data with a
   specific value in some section.  */

#define INT_ASM_OP		".quad"

/* Biggest alignment supported by the object file format of this
   machine.  Use this macro to limit the alignment which can be
   specified using the `__attribute__ ((aligned (N)))' construct.  If
   not defined, the default value is `BIGGEST_ALIGNMENT'. 

   This value is really 2^63.  Since gcc figures the alignment in bits,
   we could only potentially get to 2^60 on suitible hosts.  Due to other
   considerations in varasm, we must restrict this to what fits in an int.  */

#define MAX_OFILE_ALIGNMENT \
  (1 << (HOST_BITS_PER_INT < 64 ? HOST_BITS_PER_INT - 2 : 62))

/* This is the pseudo-op used to generate a contiguous sequence of byte
   values from a double-quoted string WITHOUT HAVING A TERMINATING NUL
   AUTOMATICALLY APPENDED.  This is the same for most svr4 assemblers.  */

#undef ASCII_DATA_ASM_OP
#define ASCII_DATA_ASM_OP	".ascii"

/* Support const sections and the ctors and dtors sections for g++.
   Note that there appears to be two different ways to support const
   sections at the moment.  You can either #define the symbol
   READONLY_DATA_SECTION (giving it some code which switches to the
   readonly data section) or else you can #define the symbols
   EXTRA_SECTIONS, EXTRA_SECTION_FUNCTIONS, SELECT_SECTION, and
   SELECT_RTX_SECTION.  We do both here just to be on the safe side.  */

#define USE_CONST_SECTION	1

#define CONST_SECTION_ASM_OP	".section\t.rodata"

/* Define the pseudo-ops used to switch to the .ctors and .dtors sections.

   Note that we want to give these sections the SHF_WRITE attribute
   because these sections will actually contain data (i.e. tables of
   addresses of functions in the current root executable or shared library
   file) and, in the case of a shared library, the relocatable addresses
   will have to be properly resolved/relocated (and then written into) by
   the dynamic linker when it actually attaches the given shared library
   to the executing process.  (Note that on SVR4, you may wish to use the
   `-z text' option to the ELF linker, when building a shared library, as
   an additional check that you are doing everything right.  But if you do
   use the `-z text' option when building a shared library, you will get
   errors unless the .ctors and .dtors sections are marked as writable
   via the SHF_WRITE attribute.)  */

#define CTORS_SECTION_ASM_OP	".section\t.ctors,\"aw\""
#define DTORS_SECTION_ASM_OP	".section\t.dtors,\"aw\""

/* Handle the small data sections.  */
#define BSS_SECTION_ASM_OP	".section\t.bss"
#define SBSS_SECTION_ASM_OP	".section\t.sbss,\"aw\""
#define SDATA_SECTION_ASM_OP	".section\t.sdata,\"aw\""

/* On svr4, we *do* have support for the .init and .fini sections, and we
   can put stuff in there to be executed before and after `main'.  We let
   crtstuff.c and other files know this by defining the following symbols.
   The definitions say how to change sections to the .init and .fini
   sections.  This is the same for all known svr4 assemblers.  */

#define INIT_SECTION_ASM_OP	".section\t.init"
#define FINI_SECTION_ASM_OP	".section\t.fini"

/* A default list of other sections which we might be "in" at any given
   time.  For targets that use additional sections (e.g. .tdesc) you
   should override this definition in the target-specific file which
   includes this file.  */

#undef EXTRA_SECTIONS
#define EXTRA_SECTIONS in_const, in_ctors, in_dtors, in_sbss, in_sdata

/* A default list of extra section function definitions.  For targets
   that use additional sections (e.g. .tdesc) you should override this
   definition in the target-specific file which includes this file.  */

#undef EXTRA_SECTION_FUNCTIONS
#define EXTRA_SECTION_FUNCTIONS						\
  CONST_SECTION_FUNCTION						\
  SECTION_FUNCTION_TEMPLATE(ctors_section, in_ctors, CTORS_SECTION_ASM_OP) \
  SECTION_FUNCTION_TEMPLATE(dtors_section, in_dtors, DTORS_SECTION_ASM_OP) \
  SECTION_FUNCTION_TEMPLATE(sbss_section, in_sbss, SBSS_SECTION_ASM_OP)	\
  SECTION_FUNCTION_TEMPLATE(sdata_section, in_sdata, SDATA_SECTION_ASM_OP)

#undef READONLY_DATA_SECTION