som.h

linux下的gcc编译器

	       fputs (",RTNVAL=GR", FILE);				\
	     fputs ("\n", FILE);					\
	   }} while (0)

/* Output at beginning of assembler file.  */

#define ASM_FILE_START(FILE) \
do {  \
     if (TARGET_PA_20) \
       fputs("\t.LEVEL 2.0\n", FILE); \
     else if (TARGET_PA_11) \
       fputs("\t.LEVEL 1.1\n", FILE); \
     else \
       fputs("\t.LEVEL 1.0\n", FILE); \
     fputs ("\t.SPACE $PRIVATE$\n\
\t.SUBSPA $DATA$,QUAD=1,ALIGN=8,ACCESS=31\n\
\t.SUBSPA $BSS$,QUAD=1,ALIGN=8,ACCESS=31,ZERO,SORT=82\n\
\t.SPACE $TEXT$\n\
\t.SUBSPA $LIT$,QUAD=0,ALIGN=8,ACCESS=44\n\
\t.SUBSPA $CODE$,QUAD=0,ALIGN=8,ACCESS=44,CODE_ONLY\n\
\t.IMPORT $global$,DATA\n\
\t.IMPORT $$dyncall,MILLICODE\n", FILE);\
     if (profile_flag)\
       fprintf (FILE, "\t.IMPORT _mcount, CODE\n");\
     if (write_symbols != NO_DEBUG) \
       output_file_directive ((FILE), main_input_filename); \
   } while (0)

/* Output before code.  */

/* Supposedly the assembler rejects the command if there is no tab!  */
#define TEXT_SECTION_ASM_OP "\t.SPACE $TEXT$\n\t.SUBSPA $CODE$\n"

/* Output before read-only data.  */

/* Supposedly the assembler rejects the command if there is no tab!  */
#define READONLY_DATA_ASM_OP "\t.SPACE $TEXT$\n\t.SUBSPA $LIT$\n"

#define EXTRA_SECTIONS in_readonly_data

#define EXTRA_SECTION_FUNCTIONS						\
extern void readonly_data PARAMS ((void));				\
void									\
readonly_data ()							\
{									\
  if (in_section != in_readonly_data)					\
    {									\
      in_section = in_readonly_data;					\
      fprintf (asm_out_file, "%s\n", READONLY_DATA_ASM_OP);		\
    }									\
}

/* FIXME: HPUX ld generates incorrect GOT entries for "T" fixups
   which reference data within the $TEXT$ space (for example constant
   strings in the $LIT$ subspace).

   The assemblers (GAS and HP as) both have problems with handling
   the difference of two symbols which is the other correct way to
   reference constant data during PIC code generation.

   So, there's no way to reference constant data which is in the
   $TEXT$ space during PIC generation.  Instead place all constant
   data into the $PRIVATE$ subspace (this reduces sharing, but it
   works correctly).  */

#define READONLY_DATA_SECTION (flag_pic ? data_section : readonly_data)

/* Output before writable data.  */

/* Supposedly the assembler rejects the command if there is no tab!  */
#define DATA_SECTION_ASM_OP "\t.SPACE $PRIVATE$\n\t.SUBSPA $DATA$\n"

/* Output before uninitialized data.  */

#define BSS_SECTION_ASM_OP "\t.SPACE $PRIVATE$\n\t.SUBSPA $BSS$\n"

/* We must not have a reference to an external symbol defined in a
   shared library in a readonly section, else the SOM linker will
   complain.

   So, we force exception information into the data section.  */
#define TARGET_ASM_EXCEPTION_SECTION data_section

/* This is how to output a command to make the user-level label named NAME
   defined for reference from other files.

   We call assemble_name, which in turn sets TREE_SYMBOL_REFERENCED.  This
   macro will restore the original value of TREE_SYMBOL_REFERENCED to avoid
   placing useless function definitions in the output file.

   Also note that the SOM based tools need the symbol imported as a CODE
   symbol, while the ELF based tools require the symbol to be imported as
   an ENTRY symbol.  What a crock.  */

#define ASM_OUTPUT_EXTERNAL(FILE, DECL, NAME)	\
  do { int save_referenced;					\
       save_referenced = TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (DECL)); \
       fputs ("\t.IMPORT ", FILE);				\
       assemble_name (FILE, NAME);				\
       if (FUNCTION_NAME_P (NAME))     				\
	 fputs (",CODE\n", FILE);				\
       else							\
	 fputs (",DATA\n", FILE);				\
       TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (DECL)) = save_referenced; \
     } while (0)

/* The bogus HP assembler requires ALL external references to be
   "imported", even library calls. They look a bit different, so
   here's this macro.

   Also note not all libcall names are passed to pa_encode_section_info
   (__main for example).  To make sure all libcall names have section
   info recorded in them, we do it here.  We must also ensure that
   we don't import a libcall that has been previously exported since
   the HP assembler may change an ENTRY symbol to a CODE symbol.  */

#define ASM_OUTPUT_EXTERNAL_LIBCALL(FILE, RTL) \
  do { const char *name;						\
       tree id;								\
									\
       if (!function_label_operand (RTL, VOIDmode))			\
	 hppa_encode_label (RTL);					\
									\
       name = (*targetm.strip_name_encoding) (XSTR ((RTL), 0));		\
       id = maybe_get_identifier (name);				\
       if (! id || ! TREE_SYMBOL_REFERENCED (id))			\
	 {								\
	   fputs ("\t.IMPORT ", FILE);					\
	   assemble_name (FILE, XSTR ((RTL), 0));		       	\
	   fputs (",CODE\n", FILE);					\
	 }								\
     } while (0)

/* We want __gcc_plt_call to appear in every program built by
   gcc, so we make a reference to it out of __main.
   We use the asm statement to fool the optimizer into not
   removing the dead (but important) initialization of
   REFERENCE.  */

#define DO_GLOBAL_DTORS_BODY			\
do {						\
  extern void __gcc_plt_call ();		\
  void (*reference)() = &__gcc_plt_call;	\
  func_ptr *p;					\
  __asm__ ("" : : "r" (reference));		\
  for (p = __DTOR_LIST__ + 1; *p; )		\
    (*p++) ();					\
} while (0)

/* The .align directive in the HP assembler allows up to a 32 alignment.  */
#define MAX_OFILE_ALIGNMENT 32768

/* The SOM linker hardcodes paths into binaries.  As a result, dotdots
   must be removed from library prefixes to prevent binaries from depending
   on the location of the GCC tool directory.  The downside is GCC
   cannot be moved after installation using a symlink.  */
#define ALWAYS_STRIP_DOTDOT 1

/* Aggregates with a single float or double field should be passed and
   returned in the general registers.  */
#define MEMBER_TYPE_FORCES_BLK(FIELD, MODE) (MODE==SFmode || MODE==DFmode)

/* If GAS supports weak, we can support weak when we have working linker
   support for secondary definitions and are generating code for GAS.  */
#ifdef HAVE_GAS_WEAK
#define SUPPORTS_WEAK (TARGET_SOM_SDEF && TARGET_GAS)
#else
#define SUPPORTS_WEAK 0
#endif

/* We can support one only if we support weak.  */
#define SUPPORTS_ONE_ONLY SUPPORTS_WEAK

/* Use weak (secondary definitions) to make one only declarations.  */
#define MAKE_DECL_ONE_ONLY(DECL) (DECL_WEAK (DECL) = 1)

/* This is how we tell the assembler that a symbol is weak.  The SOM
   weak implementation uses the secondary definition (sdef) flag.

   The behavior of sdef symbols is similar to ELF weak symbols in that
   multiple definitions can occur without incurring a link error.
   However, they differ in the following ways:
     1) Undefined sdef symbols are not allowed.
     2) The linker searches for undefined sdef symbols and will load an
	archive library member to resolve an undefined sdef symbol.
     3) The exported symbol from a shared library is a primary symbol
        rather than a sdef symbol.  Thus, more care is needed in the
	ordering of libraries.

   It appears that the linker discards extra copies of "weak" functions
   when linking shared libraries, independent of whether or not they
   are in their own section.  In linking final executables, -Wl,-O can
   be used to remove dead procedures.  Thus, support for named sections
   is not needed and in previous testing caused problems with various
   HP tools.  */
#define ASM_WEAKEN_LABEL(FILE,NAME) \
  do { fputs ("\t.weak\t", FILE);				\
       assemble_name (FILE, NAME);				\
       fputc ('\n', FILE);					\
       if (! FUNCTION_NAME_P (NAME))				\
	 {							\
	   fputs ("\t.EXPORT ", FILE);				\
	   assemble_name (FILE, NAME);				\
	   fputs (",DATA\n", FILE);				\
	 }							\
  } while (0)

/* We can't handle weak aliases, and therefore can't support pragma weak.
   Suppress the use of pragma weak in gthr-dce.h and gthr-posix.h.  */
#define GTHREAD_USE_WEAK 0