path: root/packages/glibc/2.12.1/0050-do-not-use-libgcc_eh.patch

commit 95f5a9a866695da4e038aa4e6ccbbfd5d9cf63b7
Author: Joseph Myers <joseph@codesourcery.com>
Date:   Tue Jul 3 19:14:59 2012 +0000

    Avoid use of libgcc_s and libgcc_eh when building glibc.

---
 Makeconfig         |   69 ++++++++++++++++++++++++++++++++++++++++++++++-------
 Rules              |   39 +++++++++++++++++++++++------
 elf/Makefile       |    6 +++-
 elf/static-stubs.c |   46 +++++++++++++++++++++++++++++++++++
 4 files changed, 142 insertions(+), 18 deletions(-)

--- a/Makeconfig
+++ b/Makeconfig
@@ -429,9 +429,9 @@
 LDFLAGS-rtld += $(hashstyle-LDFLAGS)
 endif
 
-# Command for linking programs with the C library.
+# Commands for linking programs with the C library.
 ifndef +link
-+link = $(CC) -nostdlib -nostartfiles -o $@ \
++link-before-libc = $(CC) -nostdlib -nostartfiles -o $@ \
 	      $(sysdep-LDFLAGS) $(config-LDFLAGS) $(LDFLAGS) $(LDFLAGS-$(@F)) \
 	      $(combreloc-LDFLAGS) $(relro-LDFLAGS) $(hashstyle-LDFLAGS) \
 	      $(addprefix $(csu-objpfx),$(start-installed-name)) \
@@ -440,7 +440,10 @@
 						     $(start-installed-name))\
 			   $(+preinit) $(link-extra-libs) \
 			   $(common-objpfx)libc% $(+postinit),$^) \
-	      $(link-extra-libs) $(link-libc) $(+postctor) $(+postinit)
+	      $(link-extra-libs)
++link-after-libc = $(+postctor) $(+postinit)
++link = $(+link-before-libc) $(link-libc) $(+link-after-libc)
++link-tests = $(+link-before-libc) $(link-libc-tests) $(+link-after-libc)
 endif
 # Command for linking PIE programs with the C library.
 ifndef +link-pie
@@ -457,7 +460,7 @@
 endif
 # Command for statically linking programs with the C library.
 ifndef +link-static
-+link-static = $(CC) -nostdlib -nostartfiles -static -o $@ \
++link-static-before-libc = $(CC) -nostdlib -nostartfiles -static -o $@ \
 	      $(sysdep-LDFLAGS) $(LDFLAGS) $(LDFLAGS-$(@F))  \
 	      $(addprefix $(csu-objpfx),$(static-start-installed-name)) \
 	      $(+preinit) $(+prector) \
@@ -465,7 +468,12 @@
 						     $(start-installed-name))\
 			   $(+preinit) $(link-extra-libs-static) \
 			   $(common-objpfx)libc% $(+postinit),$^) \
-	      $(link-extra-libs-static) $(link-libc-static) $(+postctor) $(+postinit)
+	      $(link-extra-libs-static) $(link-libc-static)
++link-static-after-libc = $(+postctor) $(+postinit)
++link-static = $(+link-static-before-libc) $(link-libc-static) \
+	       $(+link-static-after-libc)
++link-static-tests = $(+link-static-before-libc) $(link-libc-static-tests) \
+		     $(+link-static-after-libc)
 endif
 # Command for statically linking bounded-pointer programs with the C library.
 ifndef +link-bounded
@@ -490,10 +498,12 @@
 # We need the versioned name of libc.so in the deps of $(others) et al
 # so that the symlink to libc.so is created before anything tries to
 # run the linked programs.
-link-libc = -Wl,-rpath-link=$(rpath-link) \
+link-libc-before-gnulib = -Wl,-rpath-link=$(rpath-link) \
 	    $(common-objpfx)libc.so$(libc.so-version) \
 	    $(common-objpfx)$(patsubst %,$(libtype.oS),c) \
-	    $(as-needed) $(common-objpfx)elf/ld.so $(no-as-needed) $(gnulib)
+	    $(as-needed) $(common-objpfx)elf/ld.so $(no-as-needed)
+link-libc = $(link-libc-before-gnulib) $(gnulib)
+link-libc-tests = $(link-libc-before-gnulib) $(gnulib-tests)
 # This is how to find at build-time things that will be installed there.
 rpath-dirs = math elf dlfcn nss nis rt resolv crypt
 endif
@@ -504,6 +514,7 @@
 nssobjdir := $(patsubst ../$(subdir),.,$(common-objpfx)nss)
 resolvobjdir := $(patsubst ../$(subdir),.,$(common-objpfx)resolv)
 link-libc = $(common-objpfx)libc.a $(otherlibs) $(gnulib) $(common-objpfx)libc.a $(gnulib)
+link-libc-tests = $(common-objpfx)libc.a $(otherlibs) $(gnulib-tests) $(common-objpfx)libc.a $(gnulib-tests)
 endif
 endif
 
@@ -532,14 +543,50 @@
 # The static libraries.
 ifeq (yes,$(build-static))
 link-libc-static = $(common-objpfx)libc.a $(static-gnulib) $(otherlibs) $(common-objpfx)libc.a
+link-libc-static-tests = $(common-objpfx)libc.a $(static-gnulib-tests) $(otherlibs) $(common-objpfx)libc.a
 else
 ifeq (yes,$(build-shared))
 # We can try to link the programs with lib*_pic.a...
 link-libc-static = $(static-gnulib) $(common-objpfx)libc_pic.a
+link-libc-static-tests = $(static-gnulib-tests) $(common-objpfx)libc_pic.a
 endif
 endif
 link-libc-bounded = $(common-objpfx)libc_b.a $(gnulib) $(common-objpfx)libc_b.a
 
+# How to link against libgcc.  Some libgcc functions, such as those
+# for "long long" arithmetic or software floating point, can always be
+# built without use of C library headers and do not have any global
+# state so can safely be linked statically into any executable or
+# shared library requiring them; these functions are in libgcc.a.
+# Other functions, relating to exception handling, may require C
+# library headers to build and it may not be safe to have more than
+# one copy of them in a process; these functions are only in
+# libgcc_s.so and libgcc_eh.a.
+#
+# To avoid circular dependencies when bootstrapping, it is desirable
+# to avoid use of libgcc_s and libgcc_eh in building glibc.  Where any
+# glibc functionality (in particular, thread cancellation) requires
+# exception handling, this is implemented through dlopen of libgcc_s
+# to avoid unnecessary dependencies on libgcc_s by programs not using
+# that functionality; executables built with glibc do not use
+# exception handling other than through thread cancellation.
+#
+# Undefined references to functions from libgcc_eh or libgcc_s may
+# arise for code built with -fexceptions.  In the case of statically
+# linked programs installed by glibc, unwinding will never actually
+# occur at runtime and the use of elf/static-stubs.c to resolve these
+# references is safe.  In the case of statically linked test programs
+# and test programs built with -fexceptions, unwinding may occur in
+# some cases and it is preferable to link with libgcc_eh or libgcc_s
+# so that the testing is as similar as possible to how programs will
+# be built with the installed glibc.
+#
+# Some architectures have architecture-specific systems for exception
+# handling that may involve undefined references to
+# architecture-specific functions.  On those architectures,
+# gnulib-arch and static-gnulib-arch may be defined in sysdeps
+# makefiles to use additional libraries for linking executables and
+# shared libraries built by glibc.
 ifndef gnulib
 ifneq ($(have-cc-with-libunwind),yes)
   libunwind =
@@ -551,8 +598,12 @@
 else
  libgcc_eh := -Wl,--as-needed -lgcc_s$(libgcc_s_suffix) $(libunwind) -Wl,--no-as-needed
 endif
-gnulib := -lgcc $(libgcc_eh)
-static-gnulib := -lgcc -lgcc_eh $(libunwind)
+gnulib-arch =
+gnulib = -lgcc $(gnulib-arch)
+gnulib-tests := -lgcc $(libgcc_eh)
+static-gnulib-arch =
+static-gnulib = -lgcc $(static-gnulib-arch)
+static-gnulib-tests := -lgcc -lgcc_eh $(libunwind)
 libc.so-gnulib := -lgcc
 endif
 ifeq ($(elf),yes)
--- a/Rules
+++ b/Rules
@@ -104,29 +104,52 @@
 endif
 
 ifeq ($(build-programs),yes)
-binaries-all = $(others) $(sysdep-others) $(tests) $(xtests) $(test-srcs)
-binaries-static = $(others-static) $(tests-static) $(xtests-static)
+binaries-all-notests = $(others) $(sysdep-others)
+binaries-all-tests = $(tests) $(xtests) $(test-srcs)
+binaries-all = $(binaries-all-notests) $(binaries-all-tests)
+binaries-static-notests = $(others-static)
+binaries-static-tests = $(tests-static) $(xtests-static)
+binaries-static = $(binaries-static-notests) $(binaries-static-tests)
 else
-binaries-all = $(tests) $(xtests) $(test-srcs)
+binaries-all-notests =
+binaries-all-tests = $(tests) $(xtests) $(test-srcs)
+binaries-all = $(binaries-all-tests)
+binaries-static-notests =
+binaries-static-tests =
 binaries-static =
 endif
 
-binaries-shared = $(filter-out $(binaries-static), $(binaries-all))
+binaries-shared-tests = $(filter-out $(binaries-static), $(binaries-all-tests))
+binaries-shared-notests = $(filter-out $(binaries-static), $(binaries-all-notests))
 
-ifneq "$(strip $(binaries-shared))" ""
-$(addprefix $(objpfx),$(binaries-shared)): %: %.o \
+ifneq "$(strip $(binaries-shared-notests))" ""
+$(addprefix $(objpfx),$(binaries-shared-notests)): %: %.o \
   $(sort $(filter $(common-objpfx)lib%,$(link-libc))) \
   $(addprefix $(csu-objpfx),start.o) $(+preinit) $(+postinit)
 	$(+link)
 endif
 
-ifneq "$(strip $(binaries-static))" ""
-$(addprefix $(objpfx),$(binaries-static)): %: %.o \
+ifneq "$(strip $(binaries-shared-tests))" ""
+$(addprefix $(objpfx),$(binaries-shared-tests)): %: %.o \
+  $(sort $(filter $(common-objpfx)lib%,$(link-libc))) \
+  $(addprefix $(csu-objpfx),start.o) $(+preinit) $(+postinit)
+	$(+link-tests)
+endif
+
+ifneq "$(strip $(binaries-static-notests))" ""
+$(addprefix $(objpfx),$(binaries-static-notests)): %: %.o \
   $(sort $(filter $(common-objpfx)lib%,$(link-libc-static))) \
   $(addprefix $(csu-objpfx),start.o) $(+preinit) $(+postinit)
 	$(+link-static)
 endif
 
+ifneq "$(strip $(binaries-static-tests))" ""
+$(addprefix $(objpfx),$(binaries-static-tests)): %: %.o \
+  $(sort $(filter $(common-objpfx)lib%,$(link-libc-static-tests))) \
+  $(addprefix $(csu-objpfx),start.o) $(+preinit) $(+postinit)
+	$(+link-static-tests)
+endif
+
 ifeq ($(build-bounded),yes)
 binaries-bounded = $(addsuffix -bp,$(tests) $(xtests) $(test-srcs))
 $(addprefix $(objpfx),$(binaries-bounded)): %-bp: %.ob \
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -157,6 +157,8 @@
 install-bin	= sprof
 others-static   = sln
 install-rootsbin = sln
+sln-modules	:= static-stubs
+extra-objs	+= $(sln-modules:=.o)
 
 ifeq (yes,$(use-ldconfig))
 ifeq (yes,$(build-shared))
@@ -164,7 +166,7 @@
 others		+= ldconfig
 install-rootsbin += ldconfig
 
-ldconfig-modules := cache readlib xmalloc xstrdup chroot_canon
+ldconfig-modules := cache readlib xmalloc xstrdup chroot_canon static-stubs
 extra-objs	+= $(ldconfig-modules:=.o)
 
 # To find xmalloc.c and xstrdup.c
@@ -455,6 +457,8 @@
 
 $(objpfx)sprof: $(libdl)
 
+$(objpfx)sln: $(sln-modules:%=$(objpfx)%.o)
+
 $(objpfx)ldconfig: $(ldconfig-modules:%=$(objpfx)%.o)
 SYSCONF-FLAGS := -D'SYSCONFDIR="$(sysconfdir)"'
 CFLAGS-ldconfig.c = $(SYSCONF-FLAGS) -D'LIBDIR="$(libdir)"' \
--- /dev/null
+++ b/elf/static-stubs.c
@@ -0,0 +1,46 @@
+/* Stub implementations of functions to link into statically linked
+   programs without needing libgcc_eh.
+   Copyright (C) 2012 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* Avoid backtrace (and so _Unwind_Backtrace) dependencies from
+   sysdeps/unix/sysv/linux/libc_fatal.c.  */
+#include <sysdeps/posix/libc_fatal.c>
+
+#include <stdlib.h>
+#include <unwind.h>
+
+/* These programs do not use thread cancellation, so _Unwind_Resume
+   and the personality routine are never actually called.  */
+
+void
+_Unwind_Resume (struct _Unwind_Exception *exc __attribute__ ((unused)))
+{
+  abort ();
+}
+
+_Unwind_Reason_Code
+__gcc_personality_v0 (int version __attribute__ ((unused)),
+		      _Unwind_Action actions __attribute__ ((unused)),
+		      _Unwind_Exception_Class exception_class
+		      __attribute__ ((unused)),
+		      struct _Unwind_Exception *ue_header
+		      __attribute__ ((unused)),
+		      struct _Unwind_Context *context __attribute__ ((unused)))
+{
+  abort ();
+}