Upstream-Status: Backport

Signed-off-by: Khem Raj <raj.khem@gmail.com>

From 95f5a9a866695da4e038aa4e6ccbbfd5d9cf63b7 Mon Sep 17 00:00:00 2001

From: Joseph Myers <joseph@codesourcery.com>

Date: Tue, 3 Jul 2012 19:14:59 +0000

Subject: [PATCH] Avoid use of libgcc_s and libgcc_eh when building glibc.

---

 ChangeLog                  |   47 ++++++++++++++++++++++++++++++

 Makeconfig                 |   68 ++++++++++++++++++++++++++++++++++++++------

 Rules                      |   45 ++++++++++++++++++++++-------

 elf/Makefile               |    6 +++-

 elf/static-stubs.c         |   46 ++++++++++++++++++++++++++++++

 ports/ChangeLog.arm        |    7 +++++

 ports/sysdeps/arm/Makefile |    8 ++++++

 7 files changed, 206 insertions(+), 21 deletions(-)

 create mode 100644 elf/static-stubs.c

Index: a/Makeconfig

===================================================================

--- a/Makeconfig	2012-07-04 18:26:22.000000000 -0700

+++ b/Makeconfig	2012-08-14 20:16:10.197093639 -0700

@@ -415,9 +415,9 @@

 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)) \

@@ -426,7 +426,10 @@

 						     $(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

@@ -443,7 +446,7 @@

 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) \

@@ -451,7 +454,12 @@

 						     $(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

@@ -475,10 +483,12 @@

 # 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

 rpath-link = \

@@ -488,6 +498,7 @@

 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

@@ -513,8 +524,43 @@

 # The static libraries.

 link-libc-static = -Wl,--start-group $(common-objpfx)libc.a $(static-gnulib) -Wl,--end-group

+link-libc-static-tests = -Wl,--start-group $(common-objpfx)libc.a $(static-gnulib-tests) -Wl,--end-group

 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 =

@@ -522,8 +568,12 @@

   libunwind = -lunwind

 endif

 libgcc_eh := -Wl,--as-needed -lgcc_s $(libunwind) -Wl,--no-as-needed

-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

 +preinit = $(addprefix $(csu-objpfx),crti.o)

Index: a/Rules

===================================================================

--- a/Rules	2012-07-04 18:25:47.000000000 -0700

+++ b/Rules	2012-08-14 20:16:10.197093639 -0700

@@ -1,5 +1,4 @@

-# Copyright (C) 1991-2000,2002,2003,2004,2005,2006,2011

-#	Free Software Foundation, Inc.

+# Copyright (C) 1991-2012 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

@@ -103,29 +102,46 @@

 # eglibc: 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)

 ifeq (yesyes,$(have-fpie)$(build-shared))

 binaries-pie = $(others-pie) $(tests-pie) $(xtests-pie)

 else

 binaries-pie =

 endif

 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 =

 binaries-pie =

 endif

-binaries-shared = $(filter-out $(binaries-pie) $(binaries-static), \

-			       $(binaries-all))

+binaries-shared-tests = $(filter-out $(binaries-pie) $(binaries-static), \

+				     $(binaries-all-tests))

+binaries-shared-notests = $(filter-out $(binaries-pie) $(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-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-pie))" ""

 $(addprefix $(objpfx),$(binaries-pie)): %: %.o \

   $(sort $(filter $(common-objpfx)lib%,$(link-libc))) \

@@ -133,13 +149,20 @@

 	$(+link-pie)

 endif

-ifneq "$(strip $(binaries-static))" ""

-$(addprefix $(objpfx),$(binaries-static)): %: %.o \

+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 \

Index: a/elf/Makefile

===================================================================

--- a/elf/Makefile	2012-07-04 18:26:34.000000000 -0700

+++ b/elf/Makefile	2012-08-14 20:16:10.197093639 -0700

@@ -71,6 +71,8 @@

 install-bin	= sprof pldd

 others-static   = sln

 install-rootsbin = sln

+sln-modules	:= static-stubs

+extra-objs	+= $(sln-modules:=.o)

 ifeq (yes,$(use-ldconfig))

 ifeq (yes,$(build-shared))

@@ -78,7 +80,7 @@

 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)

 endif

 endif

@@ -417,6 +419,8 @@

 $(objpfx)sprof: $(libdl)

+$(objpfx)sln: $(sln-modules:%=$(objpfx)%.o)

+

 $(objpfx)ldconfig: $(ldconfig-modules:%=$(objpfx)%.o)

 $(objpfx)pldd: $(pldd-modules:%=$(objpfx)%.o)

Index: a/elf/static-stubs.c

===================================================================

--- /dev/null	1970-01-01 00:00:00.000000000 +0000

+++ a/elf/static-stubs.c	2012-08-14 20:16:10.197093639 -0700

@@ -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 ();

+}