elf.h

linux下的gcc编译器

  if (in_section != ENUM)			\
    {						\
      fprintf (asm_out_file, "%s\n", OP);	\
      in_section = ENUM;			\
    }						\
}

/* Switch into a generic section.  */
#define TARGET_ASM_NAMED_SECTION  default_elf_asm_named_section
#define TARGET_ASM_SELECT_SECTION  default_elf_select_section

#define MAKE_DECL_ONE_ONLY(DECL) (DECL_WEAK (DECL) = 1)

/* Define the strings used for the special svr4 .type and .size directives.
   These strings generally do not vary from one system running svr4 to
   another, but if a given system (e.g. m88k running svr) needs to use
   different pseudo-op names for these, they may be overridden in the
   file which includes this one.  */

#undef  TYPE_ASM_OP
#define TYPE_ASM_OP	"\t.type\t"
#undef  SIZE_ASM_OP
#define SIZE_ASM_OP	"\t.size\t"

/* This is how we tell the assembler that a symbol is weak.  */

#undef  ASM_WEAKEN_LABEL
#define ASM_WEAKEN_LABEL(FILE, NAME) \
  do { fputs ("\t.weak\t", FILE); assemble_name (FILE, NAME); \
       fputc ('\n', FILE); } while (0)

/* This is how we tell the assembler that two symbols have the same value.  */

#undef  ASM_OUTPUT_DEF
#define ASM_OUTPUT_DEF(FILE, ALIAS, NAME)			\
  do {								\
    assemble_name(FILE, ALIAS);					\
    fputs(" = ", FILE);						\
    assemble_name(FILE, NAME);					\
    fputc('\n', FILE);						\
  } while (0)

#undef  ASM_OUTPUT_DEF_FROM_DECLS
#define ASM_OUTPUT_DEF_FROM_DECLS(FILE, DECL, TARGET)		\
  do {								\
    const char *alias = XSTR (XEXP (DECL_RTL (DECL), 0), 0);	\
    const char *name = IDENTIFIER_POINTER (TARGET);		\
    if (TREE_CODE (DECL) == FUNCTION_DECL)			\
      {								\
	fputc ('$', FILE);					\
	assemble_name (FILE, alias);				\
	fputs ("..ng = $", FILE);				\
	assemble_name (FILE, name);				\
	fputs ("..ng\n", FILE);					\
      }								\
    assemble_name(FILE, alias);					\
    fputs(" = ", FILE);						\
    assemble_name(FILE, name);					\
    fputc('\n', FILE);						\
  } while (0)

/* The following macro defines the format used to output the second
   operand of the .type assembler directive.  Different svr4 assemblers
   expect various different forms for this operand.  The one given here
   is just a default.  You may need to override it in your machine-
   specific tm.h file (depending upon the particulars of your assembler).  */

#undef  TYPE_OPERAND_FMT
#define TYPE_OPERAND_FMT	"@%s"

/* Write the extra assembler code needed to declare a function's result.
   Most svr4 assemblers don't require any special declaration of the
   result value, but there are exceptions.  */

#ifndef ASM_DECLARE_RESULT
#define ASM_DECLARE_RESULT(FILE, RESULT)
#endif

/* These macros generate the special .type and .size directives which
   are used to set the corresponding fields of the linker symbol table
   entries in an ELF object file under SVR4.  These macros also output
   the starting labels for the relevant functions/objects.  */

/* Write the extra assembler code needed to declare an object properly.  */

#undef  ASM_DECLARE_OBJECT_NAME
#define ASM_DECLARE_OBJECT_NAME(FILE, NAME, DECL)		\
  do {								\
    HOST_WIDE_INT size;						\
    ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "object");		\
    size_directive_output = 0;					\
    if (!flag_inhibit_size_directive				\
	&& DECL_SIZE (DECL)					\
	&& (size = int_size_in_bytes (TREE_TYPE (DECL))) > 0)	\
      {								\
	size_directive_output = 1;				\
        ASM_OUTPUT_SIZE_DIRECTIVE (FILE, NAME, size);		\
      }								\
    ASM_OUTPUT_LABEL(FILE, NAME);				\
  } while (0)

/* Output the size directive for a decl in rest_of_decl_compilation
   in the case where we did not do so before the initializer.
   Once we find the error_mark_node, we know that the value of
   size_directive_output was set
   by ASM_DECLARE_OBJECT_NAME when it was run for the same decl.  */

#undef  ASM_FINISH_DECLARE_OBJECT
#define ASM_FINISH_DECLARE_OBJECT(FILE, DECL, TOP_LEVEL, AT_END)	\
  do {									\
    const char *name = XSTR (XEXP (DECL_RTL (DECL), 0), 0);		\
    HOST_WIDE_INT size;							\
    if (!flag_inhibit_size_directive					\
	&& DECL_SIZE (DECL)						\
	&& ! AT_END && TOP_LEVEL					\
	&& DECL_INITIAL (DECL) == error_mark_node			\
	&& !size_directive_output					\
	&& (size = int_size_in_bytes (TREE_TYPE (DECL))) > 0)		\
      {									\
	size_directive_output = 1;					\
	ASM_OUTPUT_SIZE_DIRECTIVE (FILE, name, size);			\
      }									\
  } while (0)

/* A table of bytes codes used by the ASM_OUTPUT_ASCII and
   ASM_OUTPUT_LIMITED_STRING macros.  Each byte in the table
   corresponds to a particular byte value [0..255].  For any
   given byte value, if the value in the corresponding table
   position is zero, the given character can be output directly.
   If the table value is 1, the byte must be output as a \ooo
   octal escape.  If the tables value is anything else, then the
   byte value should be output as a \ followed by the value
   in the table.  Note that we can use standard UN*X escape
   sequences for many control characters, but we don't use
   \a to represent BEL because some svr4 assemblers (e.g. on
   the i386) don't know about that.  Also, we don't use \v
   since some versions of gas, such as 2.2 did not accept it.  */

#undef  ESCAPES
#define ESCAPES \
"\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\
\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\
\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\
\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\
\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\
\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\
\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\
\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"

/* Some svr4 assemblers have a limit on the number of characters which
   can appear in the operand of a .string directive.  If your assembler
   has such a limitation, you should define STRING_LIMIT to reflect that
   limit.  Note that at least some svr4 assemblers have a limit on the
   actual number of bytes in the double-quoted string, and that they
   count each character in an escape sequence as one byte.  Thus, an
   escape sequence like \377 would count as four bytes.

   If your target assembler doesn't support the .string directive, you
   should define this to zero.  */

#undef  STRING_LIMIT
#define STRING_LIMIT	((unsigned) 256)
#undef  STRING_ASM_OP
#define STRING_ASM_OP	"\t.string\t"

/* GAS is the only Alpha/ELF assembler.  */
#undef  TARGET_GAS
#define TARGET_GAS	(1)

/* Provide a STARTFILE_SPEC appropriate for ELF.  Here we add the
   (even more) magical crtbegin.o file which provides part of the
   support for getting C++ file-scope static object constructed
   before entering `main'.   */

#undef	STARTFILE_SPEC
#define STARTFILE_SPEC \
  "%{!shared: \
     %{pg:gcrt1.o%s} %{!pg:%{p:gcrt1.o%s} %{!p:crt1.o%s}}}\
   crti.o%s %{static:crtbeginT.o%s}\
   %{!static:%{shared:crtbeginS.o%s}%{!shared:crtbegin.o%s}}"

/* Provide a ENDFILE_SPEC appropriate for ELF.  Here we tack on the
   magical crtend.o file which provides part of the support for
   getting C++ file-scope static object constructed before entering
   `main', followed by a normal ELF "finalizer" file, `crtn.o'.  */

#undef	ENDFILE_SPEC
#define ENDFILE_SPEC \
  "%{ffast-math|funsafe-math-optimizations:crtfastmath.o%s} \
   %{shared:crtendS.o%s}%{!shared:crtend.o%s} crtn.o%s"

/* We support #pragma.  */
#define HANDLE_SYSV_PRAGMA 1

/* Select a format to encode pointers in exception handling data.  CODE
   is 0 for data, 1 for code labels, 2 for function pointers.  GLOBAL is
   true if the symbol may be affected by dynamic relocations.

   Since application size is already constrained to <2GB by the form of
   the ldgp relocation, we can use a 32-bit pc-relative relocation to
   static data.  Dynamic data is accessed indirectly to allow for read
   only EH sections.  */
#define ASM_PREFERRED_EH_DATA_FORMAT(CODE,GLOBAL)       \
  (((GLOBAL) ? DW_EH_PE_indirect : 0) | DW_EH_PE_pcrel | DW_EH_PE_sdata4)

/* If defined, a C statement to be executed just prior to the output of
   assembler code for INSN.  */
#define FINAL_PRESCAN_INSN(INSN, OPVEC, NOPERANDS)	\
 (alpha_this_literal_sequence_number = 0,		\
  alpha_this_gpdisp_sequence_number = 0)
extern int alpha_this_literal_sequence_number;
extern int alpha_this_gpdisp_sequence_number;

/* Since the bits of the _init and _fini function is spread across
   many object files, each potentially with its own GP, we must assume
   we need to load our GP.  Further, the .init/.fini section can
   easily be more than 4MB away from the function to call so we can't
   use bsr.  */
#define CRT_CALL_STATIC_FUNCTION(SECTION_OP, FUNC)	\
   asm (SECTION_OP "\n"					\
"	br $29,1f\n"					\
"1:	ldgp $29,0($29)\n"				\
"	unop\n"						\
"	jsr $26," USER_LABEL_PREFIX #FUNC "\n"		\
"	.align 3\n"					\
"	.previous");

/* If we have the capability create headers for efficient EH lookup.
   As of Jan 2002, only glibc 2.2.4 can actually make use of this, but
   I imagine that other systems will catch up.  In the meantime, it
   doesn't harm to make sure that the data exists to be used later.  */
#if defined(HAVE_LD_EH_FRAME_HDR)
#define LINK_EH_SPEC "%{!static:--eh-frame-hdr} "
#endif