Makefile.in (DRIVER_DEFINES): Define ENABLE_SHARED_LIBGCC and NO_SHARED_LIBGCC_MULTILIB as required for the...

        * Makefile.in (DRIVER_DEFINES): Define ENABLE_SHARED_LIBGCC and
        NO_SHARED_LIBGCC_MULTILIB as required for the target.
        * gcc.c (init_spec): Massage the existing libgcc_spec into a
        variant that handles a shared libgcc.
        (process_command): Always validate -{static,shared}-libgcc.
        (do_spec_1): New 'M' case.
        * invoke.text (Link Options): Document -{static,shared}-libgcc.

From-SVN: r38762

4 files changed, 134 insertions, 7 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 567f293..c2fdbf9 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,15 @@
 2001-01-07  Richard Henderson  <rth@redhat.com>
 
+	* Makefile.in (DRIVER_DEFINES): Define ENABLE_SHARED_LIBGCC and
+	NO_SHARED_LIBGCC_MULTILIB as required for the target.
+	* gcc.c (init_spec): Massage the existing libgcc_spec into a
+	variant that handles a shared libgcc.
+	(process_command): Always validate -{static,shared}-libgcc.
+	(do_spec_1): New 'M' case.
+	* invoke.text (Link Options): Document -{static,shared}-libgcc.
+
+2001-01-07  Richard Henderson  <rth@redhat.com>
+
 	* Makefile.in (slibdir): New variable.
 	(libgcc.mk): Pass SHLIB_INSTALL to mklibgcc.
 	(installdirs): Create slibdir.
diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index b52678d..74ced6e 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -1248,7 +1248,10 @@ DRIVER_DEFINES = \
   -DDEFAULT_TARGET_VERSION=\"$(version)\" \
   -DDEFAULT_TARGET_MACHINE=\"$(target_alias)\" \
   -DSTANDARD_BINDIR_PREFIX=\"$(bindir)/\" \
-  -DTOOLDIR_BASE_PREFIX=\"$(unlibsubdir)/../\"
+  -DTOOLDIR_BASE_PREFIX=\"$(unlibsubdir)/../\" \
+  `test "$SHLIB_LINK" -a "@enable_shared@" = "yes" && echo "-DENABLE_SHARED_LIBGCC"` \
+  `test "$SHLIB_MULTILIB" && echo "-DNO_SHARED_LIBGCC_MULTILIB"`
+
 gcc.o: gcc.c $(CONFIG_H) system.h intl.h multilib.h \
     Makefile $(lang_specs_files) prefix.h $(GCC_H)
 	$(CC) $(ALL_CFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) \
diff --git a/gcc/gcc.c b/gcc/gcc.c
index 65fa520..9d73608 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -373,10 +373,12 @@ or with constant text in a single argument.
  %l     process LINK_SPEC as a spec.
  %L     process LIB_SPEC as a spec.
  %G     process LIBGCC_SPEC as a spec.
+ %M     output multilib_dir with directory separators replaced with "_";
+	if multilib_dir is not set or is ".", output "".
  %S     process STARTFILE_SPEC as a spec.  A capital S is actually used here.
  %E     process ENDFILE_SPEC as a spec.  A capital E is actually used here.
  %c	process SIGNED_CHAR_SPEC as a spec.
- %C     process CPP_SPEC as a spec.  A capital C is actually used here.
+ %C     process CPP_SPEC as a spec.
  %1	process CC1_SPEC as a spec.
  %2	process CC1PLUS_SPEC as a spec.
  %|	output "-" if the input for the current command is coming from a pipe.
@@ -1283,6 +1285,80 @@ init_spec ()
       next = sl;
     }
 
+#ifdef ENABLE_SHARED_LIBGCC
+  /* ??? 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 dependancies 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)
+      {
+	const char *r;
+        if (in_sep && *p == '-' && strncmp (p, "-lgcc", 5) == 0)
+	  {
+#ifdef NO_SHARED_LIBGCC_MULTILIB
+	    r = "%{shared-libgcc:-lgcc_s}%{!shared-libgcc:-lgcc}";
+#else
+	    r = "%{shared-libgcc:-lgcc_s%M}%{!shared-libgcc:-lgcc}";
+#endif
+	    obstack_grow (&obstack, r, strlen(r));
+	    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.  */
+#ifdef NO_SHARED_LIBGCC_MULTILIB
+	    r = "%{shared-libgcc:-lgcc_s}%{!shared-libgcc:libgcc.a%s}";
+#else
+	    r = "%{shared-libgcc:-lgcc_s%M}%{!shared-libgcc:libgcc.a%s}";
+#endif
+	    obstack_grow (&obstack, r, strlen(r));
+	    p += 10;
+	    in_sep = 0;
+	  }
+	else
+	  {
+	    obstack_1grow (&obstack, *p);
+	    in_sep = (*p == ' ');
+	    p += 1;
+	  }
+      }
+
+    obstack_1grow (&obstack, '\0');
+    libgcc_spec = obstack_finish (&obstack);
+  }
+#endif
+
   specs = sl;
 }
 
@@ -3552,7 +3628,7 @@ process_command (argc, argv)
            switches[n_switches].part1     = "--target-help";
            switches[n_switches].args      = 0;
            switches[n_switches].live_cond = SWITCH_OK;
-           switches[n_switches].validated     = 0;
+           switches[n_switches].validated = 0;
 
            n_switches++;
         }
@@ -3570,7 +3646,7 @@ process_command (argc, argv)
 	      switches[n_switches].part1     = "--help";
 	      switches[n_switches].args      = 0;
 	      switches[n_switches].live_cond = SWITCH_OK;
-	      switches[n_switches].validated     = 0;
+	      switches[n_switches].validated = 0;
 
 	      n_switches++;
 	    }
@@ -3697,8 +3773,10 @@ process_command (argc, argv)
 
 	  switches[n_switches].live_cond = SWITCH_OK;
 	  switches[n_switches].validated = 0;
-	  /* This is always valid, since gcc.c itself understands it.  */
-	  if (!strcmp (p, "save-temps"))
+	  /* These are always valid, since gcc.c itself understands it.  */
+	  if (!strcmp (p, "save-temps")
+	      || !strcmp (p, "static-libgcc")
+	      || !strcmp (p, "shared-libgcc"))
 	    switches[n_switches].validated = 1;
 	  else
 	    {
@@ -4346,6 +4424,23 @@ do_spec_1 (spec, inswitch, soft_matched_part)
 	      return value;
 	    break;
 
+	  case 'M':
+	    if (multilib_dir && strcmp (multilib_dir, ".") != 0)
+	      {
+		char *p;
+		const char *q;
+		size_t len;
+
+		len = strlen (multilib_dir);
+		obstack_blank (&obstack, len + 1);
+		p = obstack_next_free (&obstack) - len;
+
+		*p++ = '_';
+		for (q = multilib_dir; *q ; ++q, ++p)
+		  *p = (IS_DIR_SEPARATOR (*q) ? '_' : *q);
+	      }
+	    break;
+
 	  case 'p':
 	    {
 	      char *x = (char *) alloca (strlen (cpp_predefines) + 1);
diff --git a/gcc/invoke.texi b/gcc/invoke.texi
index c8cdb1a..941029f 100644
--- a/gcc/invoke.texi
+++ b/gcc/invoke.texi
@@ -276,7 +276,7 @@ in the following sections.
 @smallexample
 @var{object-file-name}  -l@var{library}
 -nostartfiles  -nodefaultlibs  -nostdlib
--s  -static  -shared  -symbolic
+-s  -static  -static-libgcc  -shared  -shared-libgcc  -symbolic
 -Wl,@var{option}  -Xlinker @var{option}
 -u @var{symbol}
 @end smallexample
@@ -3502,6 +3502,25 @@ libraries to link against.  Failing to supply the correct flags may lead
 to subtle defects. Supplying them in cases where they are not necessary
 is innocuous.}
 
+@item -shared-libgcc
+@itemx -static-libgcc
+On systems that provide @file{libgcc} as a shared library, these options
+force the use of either the shared or static version respectively.
+If no shared version of @file{libgcc} was built when the compiler was
+configured, these options have no effect.
+
+There are several situations in which an application should use the
+shared @file{libgcc} instead of the static version.  The most common
+of these is when the application wishes to throw and catch exceptions
+across different shared libraries.  In that case, each of the libraries
+as well as the application itself should use the shared @file{libgcc}.
+
+At present the GCC driver makes no attempt to recognize the situations
+in which the shared @file{libgcc} should be used, and defaults to using
+the static @file{libgcc} always.  This will likely change in the future,
+at which time @samp{-static-libgcc} becomes useful as a means for 
+overriding GCC's choice.
+
 @item -symbolic
 Bind references to global symbols when building a shared object.  Warn
 about any unresolved references (unless overridden by the link editor