sysv4.h

gcc-you can use this code to learn something about gcc, and inquire further into linux,

  rs6000_file_start (FILE, TARGET_CPU_DEFAULT);				\
} while (0)


extern int fixuplabelno;

/* Handle constructors specially for -mrelocatable.  */
#define TARGET_ASM_CONSTRUCTOR  rs6000_elf_asm_out_constructor
#define TARGET_ASM_DESTRUCTOR   rs6000_elf_asm_out_destructor

/* This is the end of what might become sysv4.h.  */

/* Use DWARF 2 debugging information by default.  */
#undef  PREFERRED_DEBUGGING_TYPE
#define PREFERRED_DEBUGGING_TYPE DWARF2_DEBUG

/* Historically we have also supported stabs debugging.  */
#define DBX_DEBUGGING_INFO 1

#define TARGET_ENCODE_SECTION_INFO  rs6000_elf_encode_section_info
#define TARGET_STRIP_NAME_ENCODING  rs6000_elf_strip_name_encoding
#define TARGET_IN_SMALL_DATA_P  rs6000_elf_in_small_data_p
#define TARGET_SECTION_TYPE_FLAGS  rs6000_elf_section_type_flags

/* The ELF version doesn't encode [DS] or whatever at the end of symbols.  */

#define	RS6000_OUTPUT_BASENAME(FILE, NAME)	\
    assemble_name (FILE, NAME)

/* This is how to output a reference to a user-level label named NAME.
   `assemble_name' uses this.  */

/* Override elfos.h definition.  */
#undef	ASM_OUTPUT_LABELREF
#define	ASM_OUTPUT_LABELREF(FILE,NAME)		\
do {						\
  const char *_name = NAME;			\
  if (*_name == '@')				\
    _name++;					\
 						\
  if (*_name == '*')				\
    fprintf (FILE, "%s", _name + 1);		\
  else						\
    asm_fprintf (FILE, "%U%s", _name);		\
} while (0)

/* But, to make this work, we have to output the stabs for the function
   name *first*...  */

#define	DBX_FUNCTION_FIRST

/* This is the end of what might become sysv4dbx.h.  */

#ifndef	TARGET_VERSION
#define	TARGET_VERSION fprintf (stderr, " (PowerPC System V.4)");
#endif

#ifndef	TARGET_OS_CPP_BUILTINS
#define TARGET_OS_CPP_BUILTINS()          \
  do                                      \
    {                                     \
      builtin_define_std ("PPC");         \
      builtin_define_std ("unix");        \
      builtin_define ("__svr4__");        \
      builtin_assert ("system=unix");     \
      builtin_assert ("system=svr4");     \
      builtin_assert ("cpu=powerpc");     \
      builtin_assert ("machine=powerpc"); \
    }                                     \
  while (0)
#endif

/* Pass various options to the assembler.  */
/* Override svr4.h definition.  */
#undef	ASM_SPEC
#define	ASM_SPEC "%(asm_cpu) \
%{.s: %{mregnames} %{mno-regnames}} %{.S: %{mregnames} %{mno-regnames}} \
%{v:-V} %{Qy:} %{!Qn:-Qy} %{n} %{T} %{Ym,*} %{Yd,*} %{Wa,*:%*} \
%{mrelocatable} %{mrelocatable-lib} %{fpic:-K PIC} %{fPIC:-K PIC} \
%{memb} %{!memb: %{msdata: -memb} %{msdata=eabi: -memb}} \
%{mlittle} %{mlittle-endian} %{mbig} %{mbig-endian} \
%{!mlittle: %{!mlittle-endian: %{!mbig: %{!mbig-endian: \
    %{mcall-freebsd: -mbig} \
    %{mcall-i960-old: -mlittle} \
    %{mcall-linux: -mbig} \
    %{mcall-gnu: -mbig} \
    %{mcall-netbsd: -mbig} \
}}}}"

#define	CC1_ENDIAN_BIG_SPEC ""

#define	CC1_ENDIAN_LITTLE_SPEC "\
%{!mstrict-align: %{!mno-strict-align: \
    %{!mcall-i960-old: \
	-mstrict-align \
    } \
}}"

#define	CC1_ENDIAN_DEFAULT_SPEC "%(cc1_endian_big)"

/* Pass -G xxx to the compiler and set correct endian mode.  */
#define	CC1_SPEC "%{G*} \
%{mlittle: %(cc1_endian_little)} %{!mlittle: %{mlittle-endian: %(cc1_endian_little)}} \
%{mbig: %(cc1_endian_big)} %{!mbig: %{mbig-endian: %(cc1_endian_big)}} \
%{!mlittle: %{!mlittle-endian: %{!mbig: %{!mbig-endian: \
    %{mcall-aixdesc: -mbig %(cc1_endian_big) } \
    %{mcall-freebsd: -mbig %(cc1_endian_big) } \
    %{mcall-i960-old: -mlittle %(cc1_endian_little) } \
    %{mcall-linux: -mbig %(cc1_endian_big) } \
    %{mcall-gnu: -mbig %(cc1_endian_big) } \
    %{mcall-netbsd: -mbig %(cc1_endian_big) } \
    %{!mcall-aixdesc: %{!mcall-freebsd: %{!mcall-i960-old: %{!mcall-linux: %{!mcall-gnu: %{!mcall-netbsd: \
	    %(cc1_endian_default) \
    }}}}}} \
}}}} \
%{mno-sdata: -msdata=none } \
%{meabi: %{!mcall-*: -mcall-sysv }} \
%{!meabi: %{!mno-eabi: \
    %{mrelocatable: -meabi } \
    %{mcall-freebsd: -mno-eabi } \
    %{mcall-i960-old: -meabi } \
    %{mcall-linux: -mno-eabi } \
    %{mcall-gnu: -mno-eabi } \
    %{mcall-netbsd: -mno-eabi }}} \
%{msdata: -msdata=default} \
%{mno-sdata: -msdata=none} \
%{profile: -p}"

/* Don't put -Y P,<path> for cross compilers.  */
#ifndef CROSS_COMPILE
#define LINK_PATH_SPEC "\
%{!R*:%{L*:-R %*}} \
%{!nostdlib: %{!YP,*: \
    %{compat-bsd: \
	%{p:-Y P,/usr/ucblib:/usr/ccs/lib/libp:/usr/lib/libp:/usr/ccs/lib:/usr/lib} \
	%{!p:-Y P,/usr/ucblib:/usr/ccs/lib:/usr/lib}} \
	%{!R*: %{!L*: -R /usr/ucblib}} \
    %{!compat-bsd: \
	%{p:-Y P,/usr/ccs/lib/libp:/usr/lib/libp:/usr/ccs/lib:/usr/lib} \
	%{!p:-Y P,/usr/ccs/lib:/usr/lib}}}}"

#else
#define LINK_PATH_SPEC ""
#endif

/* Default starting address if specified.  */
#define LINK_START_SPEC "\
%{mads: %(link_start_ads) } \
%{myellowknife: %(link_start_yellowknife) } \
%{mmvme: %(link_start_mvme) } \
%{msim: %(link_start_sim) } \
%{mwindiss: %(link_start_windiss) } \
%{mcall-freebsd: %(link_start_freebsd) } \
%{mcall-linux: %(link_start_linux) } \
%{mcall-gnu: %(link_start_gnu) } \
%{mcall-netbsd: %(link_start_netbsd) } \
%{!mads: %{!myellowknife: %{!mmvme: %{!msim: %{!mwindiss: \
         %{!mcall-linux: %{!mcall-gnu: %{!mcall-netbsd:   \
         %{!mcall-freebsd: %(link_start_default) }}}}}}}}}"

#define LINK_START_DEFAULT_SPEC ""

/* Override svr4.h definition.  */
#undef	LINK_SPEC
#define	LINK_SPEC "\
%{h*} %{v:-V} %{!msdata=none:%{G*}} %{msdata=none:-G0} \
%{YP,*} %{R*} \
%{Qy:} %{!Qn:-Qy} \
%(link_shlib) \
%{!Wl,-T*: %{!T*: %(link_start) }} \
%(link_target) \
%(link_os)"

/* For now, turn off shared libraries by default.  */
#ifndef SHARED_LIB_SUPPORT
#define NO_SHARED_LIB_SUPPORT
#endif

#ifndef NO_SHARED_LIB_SUPPORT
/* Shared libraries are default.  */
#define LINK_SHLIB_SPEC "\
%{!static: %(link_path) %{!R*:%{L*:-R %*}}} \
%{mshlib: } \
%{static:-dn -Bstatic} \
%{shared:-G -dy -z text} \
%{symbolic:-Bsymbolic -G -dy -z text}"

#else
/* Shared libraries are not default.  */
#define LINK_SHLIB_SPEC "\
%{mshlib: %(link_path) } \
%{!mshlib: %{!shared: %{!symbolic: -dn -Bstatic}}} \
%{static: } \
%{shared:-G -dy -z text %(link_path) } \
%{symbolic:-Bsymbolic -G -dy -z text %(link_path) }"
#endif

/* Override the default target of the linker.  */
#define	LINK_TARGET_SPEC "\
%{mlittle: --oformat elf32-powerpcle } %{mlittle-endian: --oformat elf32-powerpcle } \
%{!mlittle: %{!mlittle-endian: %{!mbig: %{!mbig-endian: \
    %{mcall-i960-old: --oformat elf32-powerpcle} \
  }}}}"

/* Any specific OS flags.  */
#define LINK_OS_SPEC "\
%{mads: %(link_os_ads) } \
%{myellowknife: %(link_os_yellowknife) } \
%{mmvme: %(link_os_mvme) } \
%{msim: %(link_os_sim) } \
%{mwindiss: %(link_os_windiss) } \
%{mcall-freebsd: %(link_os_freebsd) } \
%{mcall-linux: %(link_os_linux) } \
%{mcall-gnu: %(link_os_gnu) } \
%{mcall-netbsd: %(link_os_netbsd) } \
%{!mads: %{!myellowknife: %{!mmvme: %{!msim: %{!mwindiss: \
         %{!mcall-freebsd: %{!mcall-linux: %{!mcall-gnu: \
         %{!mcall-netbsd: %(link_os_default) }}}}}}}}}"

#define LINK_OS_DEFAULT_SPEC ""

#define CPP_SYSV_SPEC \
"%{mrelocatable*: -D_RELOCATABLE} \
%{fpic: -D__PIC__=1 -D__pic__=1} \
%{!fpic: %{fPIC: -D__PIC__=2 -D__pic__=2}}"

/* Override rs6000.h definition.  */
#undef	CPP_SPEC
#define	CPP_SPEC "%{posix: -D_POSIX_SOURCE} %(cpp_sysv) \
%{mads: %(cpp_os_ads) } \
%{myellowknife: %(cpp_os_yellowknife) } \
%{mmvme: %(cpp_os_mvme) } \
%{msim: %(cpp_os_sim) } \
%{mwindiss: %(cpp_os_windiss) } \
%{mcall-freebsd: %(cpp_os_freebsd) } \
%{mcall-linux: %(cpp_os_linux) } \
%{mcall-gnu: %(cpp_os_gnu) } \
%{mcall-netbsd: %(cpp_os_netbsd) } \
%{!mads: %{!myellowknife: %{!mmvme: %{!msim: %{!mwindiss: \
         %{!mcall-freebsd: %{!mcall-linux: %{!mcall-gnu: \
         %{!mcall-netbsd: %(cpp_os_default) }}}}}}}}}"

#define	CPP_OS_DEFAULT_SPEC ""

/* Override svr4.h definition.  */
#undef	STARTFILE_SPEC
#define	STARTFILE_SPEC "\
%{mads: %(startfile_ads) } \
%{myellowknife: %(startfile_yellowknife) } \
%{mmvme: %(startfile_mvme) } \
%{msim: %(startfile_sim) } \
%{mwindiss: %(startfile_windiss) } \
%{mcall-freebsd: %(startfile_freebsd) } \
%{mcall-linux: %(startfile_linux) } \
%{mcall-gnu: %(startfile_gnu) } \
%{mcall-netbsd: %(startfile_netbsd) } \
%{!mads: %{!myellowknife: %{!mmvme: %{!msim: %{!mwindiss: \
         %{!mcall-freebsd: %{!mcall-linux: %{!mcall-gnu: \
         %{!mcall-netbsd: %(startfile_default) }}}}}}}}}"

#define	STARTFILE_DEFAULT_SPEC ""

/* Override svr4.h definition.  */
#undef	LIB_SPEC
#define	LIB_SPEC "\
%{mads: %(lib_ads) } \
%{myellowknife: %(lib_yellowknife) } \
%{mmvme: %(lib_mvme) } \
%{msim: %(lib_sim) } \
%{mwindiss: %(lib_windiss) } \
%{mcall-freebsd: %(lib_freebsd) } \
%{mcall-linux: %(lib_linux) } \
%{mcall-gnu: %(lib_gnu) } \
%{mcall-netbsd: %(lib_netbsd) } \
%{!mads: %{!myellowknife: %{!mmvme: %{!msim: %{!mwindiss: \
         %{!mcall-freebsd: %{!mcall-linux: %{!mcall-gnu: \
         %{!mcall-netbsd: %(lib_default) }}}}}}}}}"

#define LIB_DEFAULT_SPEC ""

/* Override svr4.h definition.  */
#undef	ENDFILE_SPEC
#define	ENDFILE_SPEC "\
%{mads: crtsavres.o%s %(endfile_ads)} \
%{myellowknife: crtsavres.o%s %(endfile_yellowknife)} \
%{mmvme: crtsavres.o%s %(endfile_mvme)} \
%{msim: crtsavres.o%s %(endfile_sim)} \
%{mwindiss: %(endfile_windiss)} \
%{mcall-freebsd: crtsavres.o%s %(endfile_freebsd) } \
%{mcall-linux: crtsavres.o%s %(endfile_linux) } \
%{mcall-gnu: crtsavres.o%s %(endfile_gnu) } \
%{mcall-netbsd: crtsavres.o%s %(endfile_netbsd) } \
%{mvxworks: crtsavres.o%s %(endfile_vxworks) } \
%{!mads: %{!myellowknife: %{!mmvme: %{!msim: %{!mwindiss: \
         %{!mcall-freebsd: %{!mcall-linux: %{!mcall-gnu: \
         %{!mcall-netbsd: %{!mvxworks: %(crtsavres_default) \
                                       %(endfile_default) }}}}}}}}}}"

#define CRTSAVRES_DEFAULT_SPEC "crtsavres.o%s"

#define	ENDFILE_DEFAULT_SPEC ""

/* Motorola ADS support.  */
#define LIB_ADS_SPEC "--start-group -lads -lc --end-group"

#define	STARTFILE_ADS_SPEC "ecrti.o%s crt0.o%s crtbegin.o%s"

#define	ENDFILE_ADS_SPEC "crtend.o%s ecrtn.o%s"

#define LINK_START_ADS_SPEC "-T ads.ld%s"

#define LINK_OS_ADS_SPEC ""

#define CPP_OS_ADS_SPEC ""

/* Motorola Yellowknife support.  */
#define LIB_YELLOWKNIFE_SPEC "--start-group -lyk -lc --end-group"

#define	STARTFILE_YELLOWKNIFE_SPEC "ecrti.o%s crt0.o%s crtbegin.o%s"

#define	ENDFILE_YELLOWKNIFE_SPEC "crtend.o%s ecrtn.o%s"

#define LINK_START_YELLOWKNIFE_SPEC "-T yellowknife.ld%s"

#define LINK_OS_YELLOWKNIFE_SPEC ""

#define CPP_OS_YELLOWKNIFE_SPEC ""

/* Motorola MVME support.  */
#define LIB_MVME_SPEC "--start-group -lmvme -lc --end-group"

#define	STARTFILE_MVME_SPEC "ecrti.o%s crt0.o%s crtbegin.o%s"

#define	ENDFILE_MVME_SPEC "crtend.o%s ecrtn.o%s"

#define LINK_START_MVME_SPEC "-Ttext 0x40000"

#define LINK_OS_MVME_SPEC ""

#define CPP_OS_MVME_SPEC ""

/* PowerPC simulator based on netbsd system calls support.  */
#define LIB_SIM_SPEC "--start-group -lsim -lc --end-group"

#define	STARTFILE_SIM_SPEC "ecrti.o%s sim-crt0.o%s crtbegin.o%s"

#define	ENDFILE_SIM_SPEC "crtend.o%s ecrtn.o%s"

#define LINK_START_SIM_SPEC ""

#define LINK_OS_SIM_SPEC "-m elf32ppcsim"

#define CPP_OS_SIM_SPEC ""

/* FreeBSD support.  */

#define CPP_OS_FREEBSD_SPEC	"\
  -D__ELF__ -D__PPC__ -D__ppc__ -D__PowerPC__ -D__powerpc__ \
  -Acpu=powerpc -Amachine=powerpc"

#define	STARTFILE_FREEBSD_SPEC	FBSD_STARTFILE_SPEC
#define ENDFILE_FREEBSD_SPEC	FBSD_ENDFILE_SPEC
#define LIB_FREEBSD_SPEC	FBSD_LIB_SPEC
#define LINK_START_FREEBSD_SPEC	""

#define LINK_OS_FREEBSD_SPEC "\
  %{p:%e`-p' not supported; use `-pg' and gprof(1)} \
    %{Wl,*:%*} \
    %{v:-V} \
    %{assert*} %{R*} %{rpath*} %{defsym*} \