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From 95f5a9a866695da4e038aa4e6ccbbfd5d9cf63b7 Mon Sep 17 00:00:00 2001From: Joseph Myers <joseph@codesourcery.com>Date: Tue, 3 Jul 2012 19:14:59 +0000Subject: [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
diff --git a/Makeconfig b/Makeconfig
index 417fa50..859b588 100644
--- a/Makeconfig
+++ b/Makeconfig
@@ -415,9 +415,9 @@ LDFLAGS.so += $(hashstyle-LDFLAGS)
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 @@ ifndef +link
$(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 @@ ifndef +link-pie
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 @@ ifndef +link-static
$(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) \
+ $(+link-static-after-libc)
endif # Command for statically linking bounded-pointer programs with the C library. ifndef +link-bounded@@ -475,10 +483,12 @@ ifeq (yes,$(build-shared))
# 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 @@ else
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 @@ endif
# 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 @@ else
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)diff --git a/Rules b/Rules
index 3c61a29..17d938e 100644
--- a/Rules
+++ b/Rules
@@ -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 @@ xtests: tests $(xtests:%=$(objpfx)%.out) $(xtests-bp.out)
endif ifeq ($(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 @@ $(addprefix $(objpfx),$(binaries-pie)): %: %.o \
$(+link-pie) endif -ifneq "$(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 \diff --git a/elf/Makefile b/elf/Makefile
index 0c26ce5..9054199 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -71,6 +71,8 @@ others = sprof sln pldd
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-static += ldconfig
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@@ -411,6 +413,8 @@ $(objpfx)ldd: ldd.bash.in $(common-objpfx)soversions.mk \
$(objpfx)sprof: $(libdl) +$(objpfx)sln: $(sln-modules:%=$(objpfx)%.o)
+
$(objpfx)ldconfig: $(ldconfig-modules:%=$(objpfx)%.o) $(objpfx)pldd: $(pldd-modules:%=$(objpfx)%.o)diff --git a/elf/static-stubs.c b/elf/static-stubs.c
new file mode 100644index 0000000..6c5eebc
--- /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 ();
+}
diff --git a/ports/ChangeLog.arm b/ports/ChangeLog.arm
index c411e1c..71e8b1b 100644
--- a/ports/ChangeLog.arm
+++ b/ports/ChangeLog.arm
@@ -1,3 +1,10 @@
+2012-07-03 Joseph Myers <joseph@codesourcery.com>
+
+ * sysdeps/arm/Makefile (gnulib-arch): New variable.
+ (static-gnulib-arch): Likewise.
+ [subdir = elf] ($(objpfx)libgcc-stubs.a): New rule.
+ [subdir = elf] (lib-noranlib): Depend on $(objpfx)libgcc-stubs.a.
+
2012-06-12 Joseph Myers <joseph@codesourcery.com> * sysdeps/unix/sysv/linux/arm/setcontext.S (__startcontext): Usediff --git a/ports/sysdeps/arm/Makefile b/ports/sysdeps/arm/Makefile
index 5fd5136..3bdb6b3 100644
--- a/ports/sysdeps/arm/Makefile
+++ b/ports/sysdeps/arm/Makefile
@@ -1,8 +1,16 @@
+gnulib-arch = $(elfobjdir)/libgcc-stubs.a
+static-gnulib-arch = $(elfobjdir)/libgcc-stubs.a
+
ifeq ($(subdir),elf) sysdep-dl-routines += tlsdesc dl-tlsdesc sysdep_routines += aeabi_unwind_cpp_pr1 find_exidx tlsdesc dl-tlsdesc sysdep-rtld-routines += aeabi_unwind_cpp_pr1 tlsdesc dl-tlsdesc shared-only-routines += aeabi_unwind_cpp_pr1+
+$(objpfx)libgcc-stubs.a: $(objpfx)aeabi_unwind_cpp_pr1.os
+ $(build-extra-lib)
+
+lib-noranlib: $(objpfx)libgcc-stubs.a
endif ifeq ($(subdir),csu)--
1.7.3.4
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