gcc.c (init_gcc_specs): New function.

	* gcc.c (init_gcc_specs): New function.  Make -shared-libgcc
	the default when building a shared object.
	(init_spec): Use it.
	* testsuite/lib/g++.exp: Include the directory where libgcc
	is located to the LD_LIBRARY_PATH list.
	* inovke.texi (-shared-libgcc): Document the cases in which

	* Make-lang.in (g++spec.o): Add DRIVER_DEFINES to the list
	of macros used when compiling g++spec.c.
	* g++spec.c (lang_specific_driver): Link with the shared
	libgcc by default.

From-SVN: r39408

7 files changed, 90 insertions, 16 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 415c9ea..5c53c08 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2001-02-02  Mark Mitchell  <mark@codesourcery.com>
+
+	* gcc.c (init_gcc_specs): New function.  Make -shared-libgcc 
+	the default when building a shared object.
+	(init_spec): Use it.
+	* testsuite/lib/g++.exp: Include the directory where libgcc
+	is located to the LD_LIBRARY_PATH list.
+	* inovke.texi (-shared-libgcc): Document the cases in which
+	GCC defaults to using the shared libgcc.
+	
 2001-02-02  Alexandre Oliva  <aoliva@redhat.com>
 
 	* config/fp-bit.h (MAX_USI_INT, MAX_SI_INT): Don't assume
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 996adb3..12486a4 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,10 @@
+2001-02-02  Mark Mitchell  <mark@codesourcery.com>
+
+	* Make-lang.in (g++spec.o): Add DRIVER_DEFINES to the list
+	of macros used when compiling g++spec.c.
+	* g++spec.c (lang_specific_driver): Link with the shared
+	libgcc by default.
+
 2001-01-29  Joseph S. Myers  <jsm28@cam.ac.uk>
 
 	* decl2.c (build_expr_from_tree), lex.c (make_pointer_declarator,
diff --git a/gcc/cp/Make-lang.in b/gcc/cp/Make-lang.in
index c383626..c1fe09b 100644
--- a/gcc/cp/Make-lang.in
+++ b/gcc/cp/Make-lang.in
@@ -61,7 +61,8 @@ C++ c++: cc1plus$(exeext)
 .PHONY: C++ c++
 
 g++spec.o: $(srcdir)/cp/g++spec.c system.h $(GCC_H) $(CONFIG_H)
-	$(CC) -c $(ALL_CFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $(srcdir)/cp/g++spec.c
+	$(CC) -c $(ALL_CFLAGS) $(ALL_CPPFLAGS) $(DRIVER_DEFINES) \
+		$(INCLUDES) $(srcdir)/cp/g++spec.c
 
 $(INTL_TARGETS): $(srcdir)/cp/parse.c
 
diff --git a/gcc/cp/g++spec.c b/gcc/cp/g++spec.c
index 1d18a08..fec6434 100644
--- a/gcc/cp/g++spec.c
+++ b/gcc/cp/g++spec.c
@@ -1,5 +1,5 @@
 /* Specific flags and argument handling of the C++ front-end.
-   Copyright (C) 1996, 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
+   Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
 
 This file is part of GNU CC.
 
@@ -82,6 +82,9 @@ lang_specific_driver (in_argc, in_argv, in_added_libraries)
   /* By default, we throw on the math library if we have one.  */
   int need_math = (MATH_LIBRARY[0] != '\0');
 
+  /* True if we should add -shared-libgcc to the command-line.  */
+  int shared_libgcc = 1;
+
   /* The total number of arguments with the new stuff.  */
   int argc;
 
@@ -160,6 +163,9 @@ lang_specific_driver (in_argc, in_argv, in_added_libraries)
 	      library = 0;
 	      added -= 2;
 	    }
+	  else if (strcmp (argv[i], "-static-libgcc") == 0 
+		   || strcmp (argv[i], "-static") == 0)
+	    shared_libgcc = 0;
 	  else
 	    /* Pass other options through.  */
 	    continue;
@@ -197,8 +203,14 @@ lang_specific_driver (in_argc, in_argv, in_added_libraries)
       return;
     }
 
+  /* There's no point adding -shared-libgcc if we don't have a shared
+     libgcc.  */
+#ifndef ENABLE_SHARED_LIBGCC
+  shared_libgcc = 0;
+#endif
+
   /* Make sure to have room for the trailing NULL argument.  */
-  num_args = argc + added + need_math + 1;
+  num_args = argc + added + need_math + shared_libgcc + 1;
   arglist = (const char **) xmalloc (num_args * sizeof (char *));
 
   i = 0;
@@ -258,6 +270,8 @@ lang_specific_driver (in_argc, in_argv, in_added_libraries)
     }
   if (saw_libc)
     arglist[j++] = saw_libc;
+  if (shared_libgcc)
+    arglist[j++] = "-shared-libgcc";
 
   arglist[j] = NULL;
 
diff --git a/gcc/gcc.c b/gcc/gcc.c
index f66fc82..9a7a941 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -268,6 +268,9 @@ static int execute			PARAMS ((void));
 static void clear_args			PARAMS ((void));
 static void fatal_error			PARAMS ((int));
 static void set_input			PARAMS ((const char *));
+static void init_gcc_specs              PARAMS ((struct obstack *,
+						 const char *,
+						 const char *));
 
 /* Specs are strings containing lines, each of which (if not blank)
 is made up of a program name, and arguments separated by spaces.
@@ -1252,6 +1255,35 @@ static struct spec_list *extra_specs = (struct spec_list *) 0;
 
 static struct spec_list *specs = (struct spec_list *) 0;
 
+/* Add appropriate libgcc specs to OBSTACK, taking into account
+   various permutations of -shared-libgcc, -shared, and such.  */
+
+static void
+init_gcc_specs (obstack, shared_name, static_name)
+     struct obstack *obstack;
+     const char *shared_name;
+     const char *static_name;
+{
+  char buffer[128];
+
+  /* If we see -shared-libgcc, then use the shared version.  */
+  sprintf (buffer, "%%{shared-libgcc:%s}", shared_name);
+  obstack_grow (obstack, buffer, strlen (buffer));
+  /* If we see -static-libgcc, then use the shared version.  */
+  sprintf (buffer, "%%{static-libgcc:%s}", static_name);
+  obstack_grow (obstack, buffer, strlen (buffer));
+  /* Otherwise, if we see -shared, then use the shared version.  */
+  sprintf (buffer,
+	   "%%{!shared-libgcc:%%{!static-libgcc:%%{shared:%s}}}", 
+	   shared_name);
+  obstack_grow (obstack, buffer, strlen (buffer));
+  /* Otherwise, use the static version.  */
+  sprintf (buffer, 
+	   "%%{!shared-libgcc:%%{!static-libgcc:%%{!shared:%s}}}", 
+	   static_name);
+  obstack_grow (obstack, buffer, strlen (buffer));
+}
+
 /* Initialize the specs lookup routines.  */
 
 static void
@@ -1326,15 +1358,16 @@ init_spec ()
        when given the proper command line arguments.  */
     while (*p)
       {
-	const char *r;
         if (in_sep && *p == '-' && strncmp (p, "-lgcc", 5) == 0)
 	  {
+	    init_gcc_specs (&obstack,
 #ifdef NO_SHARED_LIBGCC_MULTILIB
-	    r = "%{shared-libgcc:-lgcc_s}%{!shared-libgcc:-lgcc}";
+			    "-lgcc_s"
 #else
-	    r = "%{shared-libgcc:-lgcc_s%M}%{!shared-libgcc:-lgcc}";
+			    "-lgcc_s%M"
 #endif
-	    obstack_grow (&obstack, r, strlen(r));
+			    ,
+			    "-lgcc");
 	    p += 5;
 	    in_sep = 0;
 	  }
@@ -1342,12 +1375,14 @@ init_spec ()
 	  {
 	    /* Ug.  We don't know shared library extensions.  Hope that
 	       systems that use this form don't do shared libraries.  */
+	    init_gcc_specs (&obstack,
 #ifdef NO_SHARED_LIBGCC_MULTILIB
-	    r = "%{shared-libgcc:-lgcc_s}%{!shared-libgcc:libgcc.a%s}";
+			    "-lgcc_s"
 #else
-	    r = "%{shared-libgcc:-lgcc_s%M}%{!shared-libgcc:libgcc.a%s}";
+			    "-lgcc_s%M"
 #endif
-	    obstack_grow (&obstack, r, strlen(r));
+			    ,
+			    "libgcc.a%s");
 	    p += 10;
 	    in_sep = 0;
 	  }
diff --git a/gcc/invoke.texi b/gcc/invoke.texi
index 560041e..e161491 100644
--- a/gcc/invoke.texi
+++ b/gcc/invoke.texi
@@ -3688,11 +3688,16 @@ 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.
+Therefore, whenever you specify the @samp{-shared} option, the GCC
+driver automatically adds @samp{-shared-libgcc}, unless you explicitly
+specify @samp{-static-libgcc}.  The G++ driver automatically adds
+@samp{-shared-libgcc} when you build a main executable as well because
+for C++ programs that is typically the right thing to do.
+(Exception-handling will not work reliably otherwise.)
+
+However, when linking a main executable written in C, you must
+explicitly say @samp{-shared-libgcc} if you want to use the shared
+@file{libgcc}.
 
 @item -symbolic
 Bind references to global symbols when building a shared object.  Warn
diff --git a/gcc/testsuite/lib/g++.exp b/gcc/testsuite/lib/g++.exp
index dd71b7b..640cd40 100644
--- a/gcc/testsuite/lib/g++.exp
+++ b/gcc/testsuite/lib/g++.exp
@@ -1,4 +1,4 @@
-# Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 2000 Free Software Foundation, Inc.
+# Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 2000, 2001 Free Software Foundation, Inc.
 
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -97,6 +97,7 @@ proc g++_include_flags { args } {
 }
 
 proc g++_link_flags { args } {
+    global rootme
     global srcdir
     global ld_library_path
 
@@ -127,6 +128,7 @@ proc g++_link_flags { args } {
       if [file exists "${gccpath}/librx/librx.a"] {
           append flags "-L${gccpath}/librx "
       }
+      append ld_library_path ":${rootme}"
     } else {
       global tool_root_dir;