Re: [patch] PR40134, use a linker script on arm-linux to link with -lgcc_s -lgcc

[Jakub Jelinek <jakub at redhat dot com>]

On Mon, Jul 13, 2009 at 09:12:27AM -0400, Matthias Klose wrote:
> this doesn't seem to work together with -nostdlib, e.g. how libstdc++ is linked
> (libstdc++ ends up with undefined symbols from libgcc). Current libtool has it's
> own idea about linking with libgcc, and doesn't link with -lgcc (explicitely
> removing it from the command line if it's there). So do we have to change
> libtool at the same time to support linking with both libgcc_s and libgcc?

After discussing this with Alex on IRC today, we agreed that the linker
script for targets that need it is probably easier.

But, completely duplicating the SHLIB_LINK/SHLIB_INSTALL variables,
especially without all the variables that can tweak it, is IMHO a wrong
idea.  We should avoid the duplication.

The following patch has been tested on powerpc64-linux --with-cpu=default32
together with a
--- rs6000.c.jj	2009-09-04 16:42:37.465404822 +0200
+++ rs6000.c	2009-09-09 12:15:01.502404904 +0200
@@ -18011,7 +18011,7 @@ static bool
 no_global_regs_above (int first, bool gpr)
 {
   int i;
-  for (i = first; i < gpr ? 32 : 64 ; i++)
+  for (i = first; i < (gpr ? 32 : 64) ; i++)
     if (global_regs[i])
       return false;
   return true;
fix (I know Nathan has a more complete patch).  arm*-*-linux* could add the
same into config.gcc, similarly sh*-*-linux* (you said sh uses it already,
but I couldn't find anything like that in config/sh/t-*).

If this patch is committed, I hope Nathan could commit his rs6000 fix as
well (would it be acceptable to 4.4 as well)?

2009-09-09  Jakub Jelinek  <jakub@redhat.com>

	* config/t-slibgcc-elf-ver (SHLIB_MAKE_SOLINK, SHLIB_INSTALL_SOLINK):
	New variables.
	(SHLIB_LINK, SHLIB_INSTALL): Use them.
	* config/t-slibgcc-libgcc: New file.
	* config.gcc (powerpc*-*-linux*, powerpc*-*-gnu*): Use it.

--- gcc/config/t-slibgcc-elf-ver.jj	2009-05-04 16:46:30.000000000 +0200
+++ gcc/config/t-slibgcc-elf-ver	2009-09-09 11:45:36.000000000 +0200
@@ -28,6 +28,9 @@ SHLIB_OBJS = @shlib_objs@
 SHLIB_DIR = @multilib_dir@
 SHLIB_SLIBDIR_QUAL = @shlib_slibdir_qual@
 SHLIB_LC = -lc
+SHLIB_MAKE_SOLINK = $(LN_S) $(SHLIB_SONAME) $(SHLIB_DIR)/$(SHLIB_SOLINK)
+SHLIB_INSTALL_SOLINK = $(LN_S) $(SHLIB_SONAME) \
+	$$(DESTDIR)$$(slibdir)$(SHLIB_SLIBDIR_QUAL)/$(SHLIB_SOLINK)
 
 SHLIB_LINK = $(GCC_FOR_TARGET) $(LIBGCC2_CFLAGS) -shared -nodefaultlibs \
 	-Wl,--soname=$(SHLIB_SONAME) \
@@ -40,7 +43,7 @@ SHLIB_LINK = $(GCC_FOR_TARGET) $(LIBGCC2
 		$(SHLIB_DIR)/$(SHLIB_SONAME).backup; \
 	else true; fi && \
 	mv $(SHLIB_DIR)/$(SHLIB_SONAME).tmp $(SHLIB_DIR)/$(SHLIB_SONAME) && \
-	$(LN_S) $(SHLIB_SONAME) $(SHLIB_DIR)/$(SHLIB_SOLINK)
+	$(SHLIB_MAKE_SOLINK)
 # $(slibdir) double quoted to protect it from expansion while building
 # libgcc.mk.  We want this delayed until actual install time.
 SHLIB_INSTALL = \
@@ -48,7 +51,6 @@ SHLIB_INSTALL = \
 	$(INSTALL_DATA) $(SHLIB_DIR)/$(SHLIB_SONAME) \
 	  $$(DESTDIR)$$(slibdir)$(SHLIB_SLIBDIR_QUAL)/$(SHLIB_SONAME); \
 	rm -f $$(DESTDIR)$$(slibdir)$(SHLIB_SLIBDIR_QUAL)/$(SHLIB_SOLINK); \
-	$(LN_S) $(SHLIB_SONAME) \
-	  $$(DESTDIR)$$(slibdir)$(SHLIB_SLIBDIR_QUAL)/$(SHLIB_SOLINK)
+	$(SHLIB_INSTALL_SOLINK)
 SHLIB_MKMAP = $(srcdir)/mkmap-symver.awk
 SHLIB_MAPFILES = $(srcdir)/libgcc-std.ver
--- gcc/config/t-slibgcc-libgcc.jj	2009-09-09 12:01:29.000000000 +0200
+++ gcc/config/t-slibgcc-libgcc	2009-09-09 11:54:46.000000000 +0200
@@ -0,0 +1,32 @@
+# Copyright (C) 2009 Free Software Foundation, Inc.
+#
+# This file is part of GCC.
+#
+# GCC is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+#
+# GCC is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GCC; see the file COPYING3.  If not see
+# <http://www.gnu.org/licenses/>.
+
+# Instead of creating $(SHLIB_SOLINK) symlink create a GNU ld
+# linker script which sources in both $(SHLIB_SONAME) and libgcc.a.
+# This is needed on targets where libgcc.a contains routines that aren't in
+# $(SHLIB_SONAME) and are needed for shared libraries.
+
+SHLIB_MAKE_SOLINK = \
+	(echo "/* GNU ld script"; \
+	 echo "   Use the shared library, but some functions are only in"; \
+	 echo "   the static library.  */"; \
+	 echo "GROUP ( $(SHLIB_SONAME) libgcc.a )" \
+	) > $(SHLIB_DIR)/$(SHLIB_SOLINK)
+SHLIB_INSTALL_SOLINK = \
+	$(INSTALL_DATA) $(SHLIB_DIR)/$(SHLIB_SOLINK) \
+	  $$(DESTDIR)$$(slibdir)$(SHLIB_SLIBDIR_QUAL)/$(SHLIB_SOLINK)
--- gcc/config.gcc.jj	2009-09-03 09:59:40.000000000 +0200
+++ gcc/config.gcc	2009-09-09 12:03:28.000000000 +0200
@@ -1927,7 +1927,7 @@ powerpc-*-linux* | powerpc64-*-linux*)
 		tm_file="${tm_file} rs6000/linux.h glibc-stdint.h"
 		;;
 	esac
-	tmake_file="${tmake_file} rs6000/t-fprules-softfp soft-fp/t-softfp"
+	tmake_file="${tmake_file} t-slibgcc-libgcc rs6000/t-fprules-softfp soft-fp/t-softfp"
 	case ${target} in
 	    powerpc*-*-linux*altivec*)
 		tm_file="${tm_file} rs6000/linuxaltivec.h" ;;
@@ -1943,19 +1943,19 @@ powerpc-*-linux* | powerpc64-*-linux*)
 powerpc64-*-gnu*)
 	tm_file="${tm_file} elfos.h svr4.h freebsd-spec.h gnu.h rs6000/sysv4.h rs6000/default64.h rs6000/linux64.h rs6000/gnu.h glibc-stdint.h"
 	extra_options="${extra_options} rs6000/sysv4.opt rs6000/linux64.opt"
-	tmake_file="t-slibgcc-elf-ver t-gnu"
+	tmake_file="t-slibgcc-elf-ver t-slibgcc-libgcc t-gnu"
 	;;
 powerpc-*-gnu-gnualtivec*)
 	tm_file="${cpu_type}/${cpu_type}.h elfos.h svr4.h freebsd-spec.h gnu.h rs6000/sysv4.h rs6000/linux.h rs6000/linuxaltivec.h rs6000/gnu.h glibc-stdint.h"
 	extra_options="${extra_options} rs6000/sysv4.opt"
-	tmake_file="rs6000/t-fprules rs6000/t-fprules-fpbit rs6000/t-ppcos t-slibgcc-elf-ver t-gnu rs6000/t-ppccomm"
+	tmake_file="rs6000/t-fprules rs6000/t-fprules-fpbit rs6000/t-ppcos t-slibgcc-elf-ver t-slibgcc-libgcc t-gnu rs6000/t-ppccomm"
 	if test x$enable_threads = xyes; then
 		thread_file='posix'
 	fi
 	;;
 powerpc-*-gnu*)
 	tm_file="${cpu_type}/${cpu_type}.h elfos.h svr4.h freebsd-spec.h gnu.h rs6000/sysv4.h rs6000/linux.h rs6000/gnu.h glibc-stdint.h"
-	tmake_file="rs6000/t-fprules rs6000/t-fprules-fpbit rs6000/t-ppcos t-slibgcc-elf-ver t-gnu rs6000/t-ppccomm"
+	tmake_file="rs6000/t-fprules rs6000/t-fprules-fpbit rs6000/t-ppcos t-slibgcc-elf-ver t-slibgcc-libgcc t-gnu rs6000/t-ppccomm"
 	extra_options="${extra_options} rs6000/sysv4.opt"
 	if test x$enable_threads = xyes; then
 		thread_file='posix'


	Jakub