elf.h

gcc-2.95.3 Linux下最常用的C编译器

#define READONLY_DATA_SECTION() const_section ()

extern void text_section ();

#define CONST_SECTION_FUNCTION						\
void									\
const_section ()							\
{									\
  if (!USE_CONST_SECTION)						\
    text_section();							\
  else if (in_section != in_const)					\
    {									\
      fprintf (asm_out_file, "%s\n", CONST_SECTION_ASM_OP);		\
      in_section = in_const;						\
    }									\
}

#define SECTION_FUNCTION_TEMPLATE(FN, ENUM, OP)				\
void FN ()								\
{									\
  if (in_section != ENUM)						\
    {									\
      fprintf (asm_out_file, "%s\n", OP);				\
      in_section = ENUM;						\
    }									\
}


/* Switch into a generic section.
   This is currently only used to support section attributes.

   We make the section read-only and executable for a function decl,
   read-only for a const data decl, and writable for a non-const data decl.  */
#define ASM_OUTPUT_SECTION_NAME(FILE, DECL, NAME, RELOC) \
  fprintf (FILE, ".section\t%s,\"%s\",@progbits\n", NAME, \
	   (DECL) && TREE_CODE (DECL) == FUNCTION_DECL ? "ax" : \
	   (DECL) && DECL_READONLY_SECTION (DECL, RELOC) ? "a" : "aw")


/* A C statement (sans semicolon) to output an element in the table of
   global constructors.  */
#define ASM_OUTPUT_CONSTRUCTOR(FILE,NAME)				\
  do {									\
    ctors_section ();							\
    fprintf (FILE, "\t%s\t ", INT_ASM_OP);				\
    assemble_name (FILE, NAME);						\
    fprintf (FILE, "\n");						\
  } while (0)

/* A C statement (sans semicolon) to output an element in the table of
   global destructors.  */
#define ASM_OUTPUT_DESTRUCTOR(FILE,NAME)       				\
  do {									\
    dtors_section ();                   				\
    fprintf (FILE, "\t%s\t ", INT_ASM_OP);				\
    assemble_name (FILE, NAME);              				\
    fprintf (FILE, "\n");						\
  } while (0)

/* A C statement or statements to switch to the appropriate
   section for output of DECL.  DECL is either a `VAR_DECL' node
   or a constant of some sort.  RELOC indicates whether forming
   the initial value of DECL requires link-time relocations.  */

#define SELECT_SECTION(DECL,RELOC)					\
{									\
  if (TREE_CODE (DECL) == STRING_CST)					\
    {									\
      if (! flag_writable_strings)					\
	const_section ();						\
      else								\
	data_section ();						\
    }									\
  else if (TREE_CODE (DECL) == VAR_DECL)				\
    {									\
      if ((flag_pic && RELOC)						\
	  || !TREE_READONLY (DECL) || TREE_SIDE_EFFECTS (DECL)		\
	  || !DECL_INITIAL (DECL)					\
	  || (DECL_INITIAL (DECL) != error_mark_node			\
	      && !TREE_CONSTANT (DECL_INITIAL (DECL))))			\
	{								\
	  int size = int_size_in_bytes (TREE_TYPE (DECL));		\
	  if (size >= 0 && size <= g_switch_value)			\
	    sdata_section ();						\
	  else								\
	    data_section ();						\
	}								\
      else								\
	const_section ();						\
    }									\
  else									\
    const_section ();							\
}

/* A C statement or statements to switch to the appropriate
   section for output of RTX in mode MODE.  RTX is some kind
   of constant in RTL.  The argument MODE is redundant except
   in the case of a `const_int' rtx.  Currently, these always
   go into the const section.  */

#undef SELECT_RTX_SECTION
#define SELECT_RTX_SECTION(MODE,RTX) const_section()

/* 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.  */

#define TYPE_ASM_OP	".type"
#define SIZE_ASM_OP	".size"

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

#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.  */

#define ASM_OUTPUT_DEF(FILE,NAME1,NAME2) \
  do { assemble_name(FILE, NAME1); 	 \
       fputs(" = ", FILE);		 \
       assemble_name(FILE, NAME2);	 \
       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).  */

#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.  */

#define ASM_DECLARE_OBJECT_NAME(FILE, NAME, DECL)			\
  do {									\
    fprintf (FILE, "\t%s\t ", TYPE_ASM_OP);				\
    assemble_name (FILE, NAME);						\
    putc (',', FILE);							\
    fprintf (FILE, TYPE_OPERAND_FMT, "object");				\
    putc ('\n', FILE);							\
    size_directive_output = 0;						\
    if (!flag_inhibit_size_directive && DECL_SIZE (DECL))		\
      {									\
	size_directive_output = 1;					\
	fprintf (FILE, "\t%s\t ", SIZE_ASM_OP);				\
	assemble_name (FILE, NAME);					\
	fprintf (FILE, ",%d\n",  int_size_in_bytes (TREE_TYPE (DECL)));	\
      }									\
    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.  */

#define ASM_FINISH_DECLARE_OBJECT(FILE, DECL, TOP_LEVEL, AT_END)	\
do {									\
  char *name = XSTR (XEXP (DECL_RTL (DECL), 0), 0);			\
  if (!flag_inhibit_size_directive && DECL_SIZE (DECL)			\
      && ! AT_END && TOP_LEVEL						\
      && DECL_INITIAL (DECL) == error_mark_node				\
      && !size_directive_output)					\
    {									\
      size_directive_output = 1;					\
      fprintf (FILE, "\t%s\t ", SIZE_ASM_OP);				\
      assemble_name (FILE, name);					\
      putc (',', FILE);							\
      fprintf (FILE, HOST_WIDE_INT_PRINT_DEC,				\
	       int_size_in_bytes (TREE_TYPE (DECL)));			\
      putc ('\n', FILE);						\
    }									\
} 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.  */

#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.  */

#define STRING_LIMIT	((unsigned) 256)
#define STRING_ASM_OP	".string"

/* 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'. 

   Don't bother seeing crtstuff.c -- there is absolutely no hope of
   getting that file to understand multiple GPs.  GNU Libc provides a
   hand-coded version that is used on Linux; it could be copied here
   if there is ever a need. */
   
#undef	STARTFILE_SPEC
#define STARTFILE_SPEC \
  "%{!shared: \
     %{pg:gcrt1.o%s} %{!pg:%{p:gcrt1.o%s} %{!p:crt1.o%s}}}\
   crti.o%s 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 \
  "crtend.o%s crtn.o%s"

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

/* Undo the auto-alignment stuff from alpha.h.  ELF has unaligned data
   pseudos natively.  */
#undef UNALIGNED_SHORT_ASM_OP
#undef UNALIGNED_INT_ASM_OP
#undef UNALIGNED_DOUBLE_INT_ASM_OP