gcc.c

gcc关键代码

  INIT_STATIC_SPEC ("asm_debug",		&asm_debug),
  INIT_STATIC_SPEC ("asm_final",		&asm_final_spec),
  INIT_STATIC_SPEC ("asm_options",		&asm_options),
  INIT_STATIC_SPEC ("invoke_as",		&invoke_as),
  INIT_STATIC_SPEC ("cpp",			&cpp_spec),
  INIT_STATIC_SPEC ("cpp_options",		&cpp_options),
  INIT_STATIC_SPEC ("cpp_debug_options",	&cpp_debug_options),
  INIT_STATIC_SPEC ("cpp_unique_options",	&cpp_unique_options),
  INIT_STATIC_SPEC ("trad_capable_cpp",		&trad_capable_cpp),
  INIT_STATIC_SPEC ("cc1",			&cc1_spec),
  INIT_STATIC_SPEC ("cc1_options",		&cc1_options),
  INIT_STATIC_SPEC ("cc1plus",			&cc1plus_spec),
  INIT_STATIC_SPEC ("link_gcc_c_sequence",	&link_gcc_c_sequence_spec),
  INIT_STATIC_SPEC ("link_ssp",			&link_ssp_spec),
  INIT_STATIC_SPEC ("endfile",			&endfile_spec),
  INIT_STATIC_SPEC ("link",			&link_spec),
  INIT_STATIC_SPEC ("lib",			&lib_spec),
  INIT_STATIC_SPEC ("mfwrap",			&mfwrap_spec),
  INIT_STATIC_SPEC ("mflib",			&mflib_spec),
  INIT_STATIC_SPEC ("libgcc",			&libgcc_spec),
  INIT_STATIC_SPEC ("startfile",		&startfile_spec),
  INIT_STATIC_SPEC ("switches_need_spaces",	&switches_need_spaces),
  INIT_STATIC_SPEC ("cross_compile",		&cross_compile),
  INIT_STATIC_SPEC ("version",			&compiler_version),
  INIT_STATIC_SPEC ("multilib",			&multilib_select),
  INIT_STATIC_SPEC ("multilib_defaults",	&multilib_defaults),
  INIT_STATIC_SPEC ("multilib_extra",		&multilib_extra),
  INIT_STATIC_SPEC ("multilib_matches",		&multilib_matches),
  INIT_STATIC_SPEC ("multilib_exclusions",	&multilib_exclusions),
  INIT_STATIC_SPEC ("multilib_options",		&multilib_options),
  INIT_STATIC_SPEC ("linker",			&linker_name_spec),
  INIT_STATIC_SPEC ("link_libgcc",		&link_libgcc_spec),
  INIT_STATIC_SPEC ("md_exec_prefix",		&md_exec_prefix),
  INIT_STATIC_SPEC ("md_startfile_prefix",	&md_startfile_prefix),
  INIT_STATIC_SPEC ("md_startfile_prefix_1",	&md_startfile_prefix_1),
  INIT_STATIC_SPEC ("startfile_prefix_spec",	&startfile_prefix_spec),
  INIT_STATIC_SPEC ("sysroot_spec",             &sysroot_spec),
  INIT_STATIC_SPEC ("sysroot_suffix_spec",	&sysroot_suffix_spec),
  INIT_STATIC_SPEC ("sysroot_hdrs_suffix_spec",	&sysroot_hdrs_suffix_spec),
};

#ifdef EXTRA_SPECS		/* additional specs needed */
/* Structure to keep track of just the first two args of a spec_list.
   That is all that the EXTRA_SPECS macro gives us.  */
struct spec_list_1
{
  const char *const name;
  const char *const ptr;
};

static const struct spec_list_1 extra_specs_1[] = { EXTRA_SPECS };
static struct spec_list *extra_specs = (struct spec_list *) 0;
#endif

/* List of dynamically allocates specs that have been defined so far.  */

static struct spec_list *specs = (struct spec_list *) 0;

/* List of static spec functions.  */

static const struct spec_function static_spec_functions[] =
{
  { "if-exists",		if_exists_spec_function },
  { "if-exists-else",		if_exists_else_spec_function },
  { "replace-outfile",		replace_outfile_spec_function },
  { "version-compare",		version_compare_spec_function },
  { 0, 0 }
};

static int processing_spec_function;

/* Add appropriate libgcc specs to OBSTACK, taking into account
   various permutations of -shared-libgcc, -shared, and such.  */

#if defined(ENABLE_SHARED_LIBGCC) && !defined(REAL_LIBGCC_SPEC)

#ifndef USE_LD_AS_NEEDED
#define USE_LD_AS_NEEDED 0
#endif

static void
init_gcc_specs (struct obstack *obstack, const char *shared_name,
		const char *static_name, const char *eh_name)
{
  char *buf;

  buf = concat ("%{static|static-libgcc:", static_name, " ", eh_name,
		"}%{!static:%{!static-libgcc:",
#if USE_LD_AS_NEEDED
		"%{!shared-libgcc:", static_name,
		" --as-needed ", shared_name, " --no-as-needed}"
		"%{shared-libgcc:", shared_name, "%{!shared: ", static_name,
		"}",
#else
		"%{!shared:%{!shared-libgcc:", static_name, " ",
		eh_name, "}%{shared-libgcc:", shared_name, " ",
		static_name, "}}%{shared:",
#ifdef LINK_EH_SPEC
		"%{shared-libgcc:", shared_name,
		"}%{!shared-libgcc:", static_name, "}",
#else
		shared_name,
#endif
#endif
		"}}}", NULL);

  obstack_grow (obstack, buf, strlen (buf));
  free (buf);
}
#endif /* ENABLE_SHARED_LIBGCC */

/* Initialize the specs lookup routines.  */

static void
init_spec (void)
{
  struct spec_list *next = (struct spec_list *) 0;
  struct spec_list *sl   = (struct spec_list *) 0;
  int i;

  if (specs)
    return;			/* Already initialized.  */

  if (verbose_flag)
    notice ("Using built-in specs.\n");

#ifdef EXTRA_SPECS
  extra_specs = xcalloc (sizeof (struct spec_list),
			 ARRAY_SIZE (extra_specs_1));

  for (i = ARRAY_SIZE (extra_specs_1) - 1; i >= 0; i--)
    {
      sl = &extra_specs[i];
      sl->name = extra_specs_1[i].name;
      sl->ptr = extra_specs_1[i].ptr;
      sl->next = next;
      sl->name_len = strlen (sl->name);
      sl->ptr_spec = &sl->ptr;
      next = sl;
    }
#endif

  /* Initialize here, not in definition.  The IRIX 6 O32 cc sometimes chokes
     on ?: in file-scope variable initializations.  */
  asm_debug = ASM_DEBUG_SPEC;

  for (i = ARRAY_SIZE (static_specs) - 1; i >= 0; i--)
    {
      sl = &static_specs[i];
      sl->next = next;
      next = sl;
    }

#if defined(ENABLE_SHARED_LIBGCC) && !defined(REAL_LIBGCC_SPEC)
  /* ??? If neither -shared-libgcc nor --static-libgcc was
     seen, then we should be making an educated guess.  Some proposed
     heuristics for ELF include:

	(1) If "-Wl,--export-dynamic", then it's a fair bet that the
	    program will be doing dynamic loading, which will likely
	    need the shared libgcc.

	(2) If "-ldl", then it's also a fair bet that we're doing
	    dynamic loading.

	(3) For each ET_DYN we're linking against (either through -lfoo
	    or /some/path/foo.so), check to see whether it or one of
	    its dependencies depends on a shared libgcc.

	(4) If "-shared"

	    If the runtime is fixed to look for program headers instead
	    of calling __register_frame_info at all, for each object,
	    use the shared libgcc if any EH symbol referenced.

	    If crtstuff is fixed to not invoke __register_frame_info
	    automatically, for each object, use the shared libgcc if
	    any non-empty unwind section found.

     Doing any of this probably requires invoking an external program to
     do the actual object file scanning.  */
  {
    const char *p = libgcc_spec;
    int in_sep = 1;

    /* Transform the extant libgcc_spec into one that uses the shared libgcc
       when given the proper command line arguments.  */
    while (*p)
      {
	if (in_sep && *p == '-' && strncmp (p, "-lgcc", 5) == 0)
	  {
	    init_gcc_specs (&obstack,
			    "-lgcc_s"
#ifdef USE_LIBUNWIND_EXCEPTIONS
			    " -lunwind"
#endif
			    ,
			    "-lgcc",
			    "-lgcc_eh"
#ifdef USE_LIBUNWIND_EXCEPTIONS
# ifdef HAVE_LD_STATIC_DYNAMIC
			    " %{!static:-Bstatic} -lunwind %{!static:-Bdynamic}"
# else
			    " -lunwind"
# endif
#endif
			    );

	    p += 5;
	    in_sep = 0;
	  }
	else if (in_sep && *p == 'l' && strncmp (p, "libgcc.a%s", 10) == 0)
	  {
	    /* Ug.  We don't know shared library extensions.  Hope that
	       systems that use this form don't do shared libraries.  */
	    init_gcc_specs (&obstack,
			    "-lgcc_s",
			    "libgcc.a%s",
			    "libgcc_eh.a%s"
#ifdef USE_LIBUNWIND_EXCEPTIONS
			    " -lunwind"
#endif
			    );
	    p += 10;
	    in_sep = 0;
	  }
	else
	  {
	    obstack_1grow (&obstack, *p);
	    in_sep = (*p == ' ');
	    p += 1;
	  }
      }

    obstack_1grow (&obstack, '\0');
    libgcc_spec = XOBFINISH (&obstack, const char *);
  }
#endif
#ifdef USE_AS_TRADITIONAL_FORMAT
  /* Prepend "--traditional-format" to whatever asm_spec we had before.  */
  {
    static const char tf[] = "--traditional-format ";
    obstack_grow (&obstack, tf, sizeof(tf) - 1);
    obstack_grow0 (&obstack, asm_spec, strlen (asm_spec));
    asm_spec = XOBFINISH (&obstack, const char *);
  }
#endif
#ifdef LINK_EH_SPEC
  /* Prepend LINK_EH_SPEC to whatever link_spec we had before.  */
  obstack_grow (&obstack, LINK_EH_SPEC, sizeof(LINK_EH_SPEC) - 1);
  obstack_grow0 (&obstack, link_spec, strlen (link_spec));
  link_spec = XOBFINISH (&obstack, const char *);
#endif

  specs = sl;
}

/* Change the value of spec NAME to SPEC.  If SPEC is empty, then the spec is
   removed; If the spec starts with a + then SPEC is added to the end of the
   current spec.  */

static void
set_spec (const char *name, const char *spec)
{
  struct spec_list *sl;
  const char *old_spec;
  int name_len = strlen (name);
  int i;

  /* If this is the first call, initialize the statically allocated specs.  */
  if (!specs)
    {
      struct spec_list *next = (struct spec_list *) 0;
      for (i = ARRAY_SIZE (static_specs) - 1; i >= 0; i--)
	{
	  sl = &static_specs[i];
	  sl->next = next;
	  next = sl;
	}
      specs = sl;
    }

  /* See if the spec already exists.  */
  for (sl = specs; sl; sl = sl->next)
    if (name_len == sl->name_len && !strcmp (sl->name, name))
      break;

  if (!sl)
    {
      /* Not found - make it.  */
      sl = xmalloc (sizeof (struct spec_list));
      sl->name = xstrdup (name);
      sl->name_len = name_len;
      sl->ptr_spec = &sl->ptr;
      sl->alloc_p = 0;
      *(sl->ptr_spec) = "";
      sl->next = specs;
      specs = sl;
    }

  old_spec = *(sl->ptr_spec);
  *(sl->ptr_spec) = ((spec[0] == '+' && ISSPACE ((unsigned char)spec[1]))
		     ? concat (old_spec, spec + 1, NULL)
		     : xstrdup (spec));

#ifdef DEBUG_SPECS
  if (verbose_flag)
    notice ("Setting spec %s to '%s'\n\n", name, *(sl->ptr_spec));
#endif

  /* Free the old spec.  */
  if (old_spec && sl->alloc_p)
    free ((void *) old_spec);

  sl->alloc_p = 1;
}

/* Accumulate a command (program name and args), and run it.  */

/* Vector of pointers to arguments in the current line of specifications.  */

static const char **argbuf;

/* Number of elements allocated in argbuf.  */

static int argbuf_length;

/* Number of elements in argbuf currently in use (containing args).  */

static int argbuf_index;

/* Position in the argbuf array containing the name of the output file
   (the value associated with the "-o" flag).  */

static int have_o_argbuf_index = 0;

/* Were the options -c or -S passed.  */
static int have_c = 0;

/* Was the option -o passed.  */
static int have_o = 0;

/* This is the list of suffixes and codes (%g/%u/%U/%j) and the associated
   temp file.  If the HOST_BIT_BUCKET is used for %j, no entry is made for
   it here.  */

static struct temp_name {
  const char *suffix;	/* suffix associated with the code.  */
  int length;		/* strlen (suffix).  */
  int unique;		/* Indicates whether %g or %u/%U was used.  */
  const char *filename;	/* associated filename.  */
  int filename_length;	/* strlen (filename).  */
  struct temp_name *next;
} *temp_names;

/* Number of commands executed so far.  */

static int execution_count;

/* Number of commands that exited with a signal.  */

static int signal_count;

/* Name with which this program was invoked.  */

static const char *programname;

/* Allocate the argument vector.  */

static void
alloc_args (void)
{
  argbuf_length = 10;
  argbuf = xmalloc (argbuf_length * sizeof (const char *));
}

/* Clear out the vector of arguments (after a command is executed).  */

stati