target-specific contents for libstdc++: how to? [with actual patch!]

[Geoffrey Keating]

Due to the timing of Apple's Tiger release, we used a simpler method
of making all the libgcc functions be hidden.  Unfortunately, the
simpler method worked for everything but libstdc++, and so libstdc++
ended up exporting __eprintf in Tiger.  (This was especially annoying
since __eprintf is probably the last symbol from libgcc.a that we'd want
it to export.)  However, we're stuck with it now, and so if you want
to build a libstdc++ for Darwin you need to include __eprintf somehow.

It looks like other similar compatibility stuff goes in
src/compatibility.cc.  Is that right?  More generally, is this patch
right?  (The ugly bit is at the end.)  If not right, how should this
be done?

-- 
- Geoffrey Keating <geoffk@apple.com>

===File ~/patches/libstdc++-darwin-eprintf.patch============
2005-08-18  Geoffrey Keating  <geoffk@apple.com>

	* config/os/bsd/darwin/eprintf.ver: New.
	* src/Makefile.am (libstdc++-symbol.ver): Move outside conditionals,
	and make dependent on port symbol files.
	(libstdc++-symbol.explist): Use the generated .ver file, not
	the template.
	* src/compatibility.cc [APPLE] (__eprintf): New.

Index: config/os/bsd/darwin/eprintf.ver
===================================================================
RCS file: config/os/bsd/darwin/eprintf.ver
diff -N config/os/bsd/darwin/eprintf.ver
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ config/os/bsd/darwin/eprintf.ver	19 Aug 2005 01:59:34 -0000
@@ -0,0 +1 @@
+  __eprintf;
Index: src/Makefile.am
===================================================================
RCS file: /cvs/gcc/gcc/libstdc++-v3/src/Makefile.am,v
retrieving revision 1.151
diff -u -p -u -p -r1.151 Makefile.am
--- src/Makefile.am	17 Aug 2005 02:14:20 -0000	1.151
+++ src/Makefile.am	19 Aug 2005 01:59:34 -0000
@@ -28,10 +28,11 @@ include $(top_srcdir)/fragment.am
 toolexeclib_LTLIBRARIES = libstdc++.la
 
 # Symbol versioning for shared libraries.
-if ENABLE_SYMVERS_GNU
-version_arg = -Wl,--version-script=libstdc++-symbol.ver
-version_dep = libstdc++-symbol.ver
-libstdc++-symbol.ver:  ${glibcxx_srcdir}/$(SYMVER_MAP)
+# This could be conditional on
+# ENABLE_SYMVERS_GNU || ENABLE_SYMVERS_DARWIN_EXPORT
+# but automake doesn't support OR operations in conditionals.
+libstdc++-symbol.ver:  ${glibcxx_srcdir}/$(SYMVER_MAP) \
+		$(port_specific_symbol_files)
 	cp ${glibcxx_srcdir}/$(SYMVER_MAP) ./libstdc++-symbol.ver
 	if test "x$(port_specific_symbol_files)" != x; then \
 	  sed -n '1,/DO NOT DELETE/p' $@ > tmp.top; \
@@ -39,15 +40,19 @@ libstdc++-symbol.ver:  ${glibcxx_srcdir}
 	  cat tmp.top $(port_specific_symbol_files) tmp.bottom > $@; \
 	  rm tmp.top tmp.bottom; \
 	fi
+
+if ENABLE_SYMVERS_GNU
+version_arg = -Wl,--version-script=libstdc++-symbol.ver
+version_dep = libstdc++-symbol.ver
 else
 if ENABLE_SYMVERS_DARWIN_EXPORT
 version_arg = -Wl,-exported_symbols_list,libstdc++-symbol.explist
 version_dep = libstdc++-symbol.explist
-libstdc++-symbol.explist : ${glibcxx_srcdir}/$(SYMVER_MAP) \
+libstdc++-symbol.explist : libstdc++-symbol.ver \
 		${glibcxx_srcdir}/scripts/make_exports.pl \
 		$(libstdc___la_OBJECTS) $(libstdc___la_LIBADD)
 	perl ${glibcxx_srcdir}/scripts/make_exports.pl \
-	  ${glibcxx_srcdir}/$(SYMVER_MAP) \
+	  libstdc++-symbol.ver \
 	  $(libstdc___la_OBJECTS:%.lo=.libs/%.o) \
 	 `echo $(libstdc___la_LIBADD) | \
 	    sed 's,/\([^/.]*\)\.la,/.libs/\1.a,g'` \
@@ -169,7 +174,6 @@ libstdc___la_DEPENDENCIES = ${version_de
 libstdc___la_LDFLAGS = \
 	-version-info $(libtool_VERSION) ${version_arg} -lm 
 
-
 # Use special rules for the deprecated source files so that they find
 # deprecated include files.
 GLIBCXX_INCLUDE_DIR=$(glibcxx_builddir)/include
Index: src/compatibility.cc
===================================================================
RCS file: /cvs/gcc/gcc/libstdc++-v3/src/compatibility.cc,v
retrieving revision 1.4
diff -u -p -u -p -r1.4 compatibility.cc
--- src/compatibility.cc	17 Aug 2005 02:14:20 -0000	1.4
+++ src/compatibility.cc	19 Aug 2005 01:59:34 -0000
@@ -361,3 +361,28 @@ namespace std
 #undef _GLIBCXX_APPLY_SYMVER
 
 #endif
+
+#ifdef __APPLE__
+#if (defined(__ppc__) || defined (__ppc64__)) && defined (PIC)
+/* __eprintf shouldn't have been made visible from libstdc++, or
+   anywhere, but on Mac OS X 10.4 it was defined in
+   libstdc++.6.0.3.dylib; so on that platform we have to keep defining
+   it to keep binary compatibility.  We can't just put the libgcc
+   version in the export list, because that doesn't work; once a
+   symbol is marked as hidden, it stays that way.  */
+
+#include <cstdio>
+#include <cstdlib>
+
+using namespace std;
+
+extern "C" void
+__eprintf (const char *string, const char *expression,
+	   unsigned int line, const char *filename)
+{
+  fprintf (stderr, string, expression, line, filename);
+  fflush (stderr);
+  abort ();
+}
+#endif
+#endif /* __APPLE__ */
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