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Re: PATCH] PR target/65612: Multiversioning doesn't work with DSO nor PIE
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Jack Howarth <howarth dot at dot gcc at gmail dot com>, Ian Lance Taylor <ian at airs dot com>
- Cc: Jakub Jelinek <jakub at redhat dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>, Uros Bizjak <ubizjak at gmail dot com>, Iain Sandoe <iain at codesourcery dot com>, Mike Stump <mikestump at comcast dot net>
- Date: Tue, 31 Mar 2015 08:58:23 -0700
- Subject: Re: PATCH] PR target/65612: Multiversioning doesn't work with DSO nor PIE
- Authentication-results: sourceware.org; auth=none
- References: <20150330022527 dot GA4148 at gmail dot com> <CAMe9rOrUpMmt8XyqO9fXZB-Bn+tRs-AKHTaQzu7jeGCZFXen8g at mail dot gmail dot com> <CAMe9rOp_LfJ8C4Xh4NoRD=rTutNCeqwN_OV=8+c5rFfnRHbV_g at mail dot gmail dot com> <CAMe9rOrGCRJhWpNT0hMJwKCG2+vaDsaRou7JV0tdjiANnmRm=g at mail dot gmail dot com> <CAJMcOU8nON6S=+be8C94F_tB8-VPCusa8VrEq_f5P2PZCdk7vg at mail dot gmail dot com> <CAMe9rOo2ORmyvndySKr3vzEQmZScpKQfnVVw7HW94BXvPFJqdQ at mail dot gmail dot com> <20150331053855 dot GB2121 at tucnak dot redhat dot com> <CAMe9rOrm=9gkqjFwEX8GVtri3t2mSmgOqfm_Q+LizCJqbLSAKQ at mail dot gmail dot com> <CAJMcOU_Pjryr7TxKx9zYKBtVEvBj8bmXDr=UBqShyE0CPr-cOA at mail dot gmail dot com>
On Tue, Mar 31, 2015 at 7:25 AM, Jack Howarth <howarth.at.gcc@gmail.com> wrote:
> H.J.,
> While the latest patch fails to bootstrap on x86_64-apple-darwin14...
>
> _restore_x86_fp_state in os-unix-sysdep.o
> _sysdep_save_fp_ctrl_state in os-unix-sysdep.o
> ld: symbol(s) not found for architecture x86_64
> collect2: error: ld returned 1 exit status
> Makefile:540: recipe for target 'libcilkrts.la' failed
> make[2]: *** [libcilkrts.la] Error 1
> make[2]: Leaving directory
> '/sw/src/fink.build/gcc5-5.0.0-1/darwin_objdir/x86_64-apple-darwin14.3.0/libcilkrts'
> Makefile:13569: recipe for target 'all-target-libcilkrts' failed
> make[1]: *** [all-target-libcilkrts] Error 2
> make[1]: Leaving directory '/sw/src/fink.build/gcc5-5.0.0-1/darwin_objdir'
> Makefile:21064: recipe for target 'bootstrap' failed
> make: *** [bootstrap] Error 2
>
> as darwin will require the new usage of libgcc_nonshared.a to be added
> to the spec handling with...
Here is the updated patch to make libgcc_nonshared.a optional
so that it is only needed on Linux.
> Index: gcc/config/darwin.h
> ===================================================================
> --- gcc/config/darwin.h (revision 221794)
> +++ gcc/config/darwin.h (working copy)
> @@ -325,7 +325,7 @@ extern GTY(()) int darwin_ms_struct;
> need symbols from -lgcc. */
> #undef REAL_LIBGCC_SPEC
> #define REAL_LIBGCC_SPEC \
> - "%{static-libgcc|static: -lgcc_eh -lgcc; \
> + "%{static-libgcc|static: -lgcc_eh -lgcc_nonshared -lgcc; \
> shared-libgcc|fexceptions|fgnu-runtime: \
> %:version-compare(!> 10.5 mmacosx-version-min= -lgcc_s.10.4) \
> %:version-compare(>< 10.5 10.6 mmacosx-version-min= -lgcc_s.10.5) \
> @@ -336,7 +336,7 @@ extern GTY(()) int darwin_ms_struct;
> %:version-compare(>< 10.5 10.6 mmacosx-version-min= -lgcc_s.10.5) \
> %:version-compare(!> 10.5 mmacosx-version-min= -lgcc_ext.10.4) \
> %:version-compare(>= 10.5 mmacosx-version-min= -lgcc_ext.10.5) \
> - -lgcc }"
> + -lgcc_nonshared -lgcc }"
>
> /* We specify crt0.o as -lcrt0.o so that ld will search the library path.
>
> Jack
> ps One minor nit...
>
> Index: gcc/gcc.c
> ===================================================================
> --- gcc/gcc.c (revision 221794)
> +++ gcc/gcc.c (working copy)
> @@ -1566,11 +1566,13 @@ init_spec (void)
> if (in_sep && *p == '-' && strncmp (p, "-lgcc", 5) == 0)
> {
> init_gcc_specs (&obstack,
> + "-lgcc_nonshared "
> "-lgcc_s"
> #ifdef USE_LIBUNWIND_EXCEPTIONS
> " -lunwind"
> #endif
> ,
> + "-lgcc_nonshared "
> "-lgcc",
> "-lgcc_eh"
> #ifdef USE_LIBUNWIND_EXCEPTIONS
> @@ -1591,7 +1593,9 @@ init_spec (void)
> /* Ug. We don't know shared library extensions. Hope that
> systems that use this form don't do shared libraries. */
> init_gcc_specs (&obstack,
> + "libgcc_nonshared.a%s "
> "-lgcc_s",
> + "libgcc_nonshared.a%s "
> "libgcc.a%s",
> "libgcc_eh.a%s"
>
> You seem to have unnecessary trailing whitespace at the end of these flags.
>
The white space is needed to avoid -lgcc_nonshared-lgcc_s.
--
H.J.
---
We shouldn't call external function, __cpu_indicator_init, while an object
is being relocated since its .got.plt section hasn't been updated. It
works for non-PIE since no update on .got.plt section is required. This
patch hides __cpu_indicator_init/__cpu_model from linker to force linker
to resolve __cpu_indicator_init/__cpu_model to their hidden definitions
in libgcc_nonshared.a while providing backward binary compatibility. The
new libgcc_nonshared.a is always linked togther with -lgcc_s and -lgcc.
gcc/
PR target/65612
* gcc.c (init_spec): Add -lgcc_nonshared/libgcc_nonshared.a%s
to -lgcc_s.
gcc/testsuite/
PR target/65612
* g++.dg/ext/mv18.C: New test.
* g++.dg/ext/mv19.C: Likewise.
* g++.dg/ext/mv20.C: Likewise.
* g++.dg/ext/mv21.C: Likewise.
* g++.dg/ext/mv22.C: Likewise.
* g++.dg/ext/mv23.C: Likewise.
libgcc/
PR target/65612
* Makefile.in (LIB2ADDNONSHARED): New.
(libgcc-nonshared-objects): Likewise.
(libgcc_nonshared.a): Likewise.
Check unsupported files in LIB2ADDNONSHARED.
(iter-items): Add $(LIB2ADDNONSHARED).
(all): Depend on libgcc_nonshared.a.
($(libgcc-nonshared-objects)): Depend on libgcc_tm.h.
(install-leaf): Install libgcc_nonshared.a.
* shared-object.mk: Check empty $o.
* config/i386/cpuinfo.c (__cpu_model): Initialize.
(__cpu_indicator_init@GCC_4.8.0): New.
(__cpu_model@GCC_4.8.0): Likewise.
* config/i386/t-cpuinfo (LIB2ADDNONSHARED): New.
* config/i386/t-linux (HOST_LIBGCC2_CFLAGS): Add
-DUSE_ELF_SYMVER.
---
From 760b79124482860b4317f4d39fbe898cfbe8e47b Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Sun, 29 Mar 2015 18:03:49 -0700
Subject: [PATCH] Hide __cpu_indicator_init/__cpu_model from linker
We shouldn't call external function, __cpu_indicator_init, while an object
is being relocated since its .got.plt section hasn't been updated. It
works for non-PIE since no update on .got.plt section is required. This
patch hides __cpu_indicator_init/__cpu_model from linker to force linker
to resolve __cpu_indicator_init/__cpu_model to their hidden definitions
in libgcc_nonshared.a while providing backward binary compatibility. The
new libgcc_nonshared.a is always linked togther with -lgcc_s and -lgcc.
gcc/
PR target/65612
* gcc.c (init_spec): Add -lgcc_nonshared/libgcc_nonshared.a%s
to -lgcc_s.
gcc/testsuite/
PR target/65612
* g++.dg/ext/mv18.C: New test.
* g++.dg/ext/mv19.C: Likewise.
* g++.dg/ext/mv20.C: Likewise.
* g++.dg/ext/mv21.C: Likewise.
* g++.dg/ext/mv22.C: Likewise.
* g++.dg/ext/mv23.C: Likewise.
libgcc/
PR target/65612
* Makefile.in (LIB2ADDNONSHARED): New.
(libgcc-nonshared-objects): Likewise.
(libgcc_nonshared.a): Likewise.
Check unsupported files in LIB2ADDNONSHARED.
(iter-items): Add $(LIB2ADDNONSHARED).
(all): Depend on libgcc_nonshared.a.
($(libgcc-nonshared-objects)): Depend on libgcc_tm.h.
(install-leaf): Install libgcc_nonshared.a.
* shared-object.mk: Check empty $o.
* config/i386/cpuinfo.c (__cpu_model): Initialize.
(__cpu_indicator_init@GCC_4.8.0): New.
(__cpu_model@GCC_4.8.0): Likewise.
* config/i386/t-cpuinfo (LIB2ADDNONSHARED): New.
* config/i386/t-linux (HOST_LIBGCC2_CFLAGS): Add
-DUSE_ELF_SYMVER.
---
gcc/gcc.c | 2 ++
gcc/testsuite/g++.dg/ext/mv18.C | 7 +++++++
gcc/testsuite/g++.dg/ext/mv19.C | 7 +++++++
gcc/testsuite/g++.dg/ext/mv20.C | 7 +++++++
gcc/testsuite/g++.dg/ext/mv21.C | 7 +++++++
gcc/testsuite/g++.dg/ext/mv22.C | 7 +++++++
gcc/testsuite/g++.dg/ext/mv23.C | 7 +++++++
libgcc/Makefile.in | 22 +++++++++++++++++++---
libgcc/config/i386/cpuinfo.c | 7 ++++++-
libgcc/config/i386/t-cpuinfo | 1 +
libgcc/config/i386/t-linux | 2 +-
libgcc/shared-object.mk | 2 ++
12 files changed, 73 insertions(+), 5 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/ext/mv18.C
create mode 100644 gcc/testsuite/g++.dg/ext/mv19.C
create mode 100644 gcc/testsuite/g++.dg/ext/mv20.C
create mode 100644 gcc/testsuite/g++.dg/ext/mv21.C
create mode 100644 gcc/testsuite/g++.dg/ext/mv22.C
create mode 100644 gcc/testsuite/g++.dg/ext/mv23.C
diff --git a/gcc/gcc.c b/gcc/gcc.c
index d956c36..3fbd549 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -1566,6 +1566,7 @@ init_spec (void)
if (in_sep && *p == '-' && strncmp (p, "-lgcc", 5) == 0)
{
init_gcc_specs (&obstack,
+ "-lgcc_nonshared "
"-lgcc_s"
#ifdef USE_LIBUNWIND_EXCEPTIONS
" -lunwind"
@@ -1591,6 +1592,7 @@ init_spec (void)
/* Ug. We don't know shared library extensions. Hope that
systems that use this form don't do shared libraries. */
init_gcc_specs (&obstack,
+ "libgcc_nonshared.a%s "
"-lgcc_s",
"libgcc.a%s",
"libgcc_eh.a%s"
diff --git a/gcc/testsuite/g++.dg/ext/mv18.C b/gcc/testsuite/g++.dg/ext/mv18.C
new file mode 100644
index 0000000..1f024de
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/mv18.C
@@ -0,0 +1,7 @@
+/* Test case to check if Multiversioning works. */
+/* { dg-do run { target i?86-*-* x86_64-*-* } } */
+/* { dg-require-ifunc "" } */
+/* { dg-require-effective-target pie } */
+/* { dg-options "-O2 -fPIE -pie" } */
+
+#include "mv1.C"
diff --git a/gcc/testsuite/g++.dg/ext/mv19.C b/gcc/testsuite/g++.dg/ext/mv19.C
new file mode 100644
index 0000000..d1ea788
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/mv19.C
@@ -0,0 +1,7 @@
+/* Test case to check if Multiversioning works. */
+/* { dg-do run { target i?86-*-* x86_64-*-* } } */
+/* { dg-require-ifunc "" } */
+/* { dg-require-effective-target pie } */
+/* { dg-options "-O2 -fPIE -pie -march=x86-64" } */
+
+#include "mv14.C"
diff --git a/gcc/testsuite/g++.dg/ext/mv20.C b/gcc/testsuite/g++.dg/ext/mv20.C
new file mode 100644
index 0000000..98f7408
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/mv20.C
@@ -0,0 +1,7 @@
+/* Test case to check if Multiversioning works. */
+/* { dg-do run { target i?86-*-* x86_64-*-* } } */
+/* { dg-require-ifunc "" } */
+/* { dg-require-effective-target pie } */
+/* { dg-options "-O2 -fPIE -pie -march=x86-64" } */
+
+#include "mv15.C"
diff --git a/gcc/testsuite/g++.dg/ext/mv21.C b/gcc/testsuite/g++.dg/ext/mv21.C
new file mode 100644
index 0000000..9708ad9
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/mv21.C
@@ -0,0 +1,7 @@
+/* Test case to check if Multiversioning works. */
+/* { dg-do run { target i?86-*-* x86_64-*-* } } */
+/* { dg-require-ifunc "" } */
+/* { dg-require-effective-target static } */
+/* { dg-options "-O2 -static" } */
+
+#include "mv1.C"
diff --git a/gcc/testsuite/g++.dg/ext/mv22.C b/gcc/testsuite/g++.dg/ext/mv22.C
new file mode 100644
index 0000000..2550136
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/mv22.C
@@ -0,0 +1,7 @@
+/* Test case to check if Multiversioning works. */
+/* { dg-do run { target i?86-*-* x86_64-*-* } } */
+/* { dg-require-ifunc "" } */
+/* { dg-require-effective-target static } */
+/* { dg-options "-O2 -static -march=x86-64" } */
+
+#include "mv14.C"
diff --git a/gcc/testsuite/g++.dg/ext/mv23.C b/gcc/testsuite/g++.dg/ext/mv23.C
new file mode 100644
index 0000000..f00afb0
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/mv23.C
@@ -0,0 +1,7 @@
+/* Test case to check if Multiversioning works. */
+/* { dg-do run { target i?86-*-* x86_64-*-* } } */
+/* { dg-require-ifunc "" } */
+/* { dg-require-effective-target static } */
+/* { dg-options "-O2 -static -march=x86-64" } */
+
+#include "mv15.C"
diff --git a/libgcc/Makefile.in b/libgcc/Makefile.in
index 88ddfea..f78b1ac 100644
--- a/libgcc/Makefile.in
+++ b/libgcc/Makefile.in
@@ -261,6 +261,10 @@ LIB2ADD =
# Assembler files should have names ending in `.S'.
LIB2ADD_ST =
+# List of extra C and assembler files to add to libgcc_nonshared.a.
+# Assembler files should have names ending in `.S'.
+LIB2ADDNONSHARED =
+
# Specify the directories to be searched for header files.
# Both . and srcdir are used, in that order,
# so that *config.h will be found in the compilation
@@ -807,8 +811,15 @@ endif
libgcc-objects += $(addsuffix $(objext),$(basename $(notdir $(LIB2ADD))))
libgcc-objects += $(addsuffix $(objext),$(basename $(notdir $(LIB2ADD_ST))))
+# Build LIB2ADDNONSHARED.
+ifneq ($(filter-out %.c %.S %.asm,$(LIB2ADDNONSHARED)),)
+$(error Unsupported files in LIB2ADDNONSHARED.)
+endif
+
+libgcc-nonshared-objects += $(addsuffix $(objext),$(basename $(notdir $(LIB2ADDNONSHARED))))
+
c_flags :=
-iter-items := $(LIB2ADD) $(LIB2ADD_ST)
+iter-items := $(LIB2ADD) $(LIB2ADD_ST) $(LIB2ADDNONSHARED)
include $(iterator)
ifeq ($(enable_shared),yes)
@@ -890,8 +901,9 @@ libgcc.a: $(libgcc-objects)
libgcov.a: $(libgcov-objects)
libunwind.a: $(libunwind-objects)
libgcc_eh.a: $(libgcc-eh-objects)
+libgcc_nonshared.a: $(libgcc-nonshared-objects)
-libgcc.a libgcov.a libunwind.a libgcc_eh.a:
+libgcc.a libgcov.a libunwind.a libgcc_eh.a libgcc_nonshared.a:
-rm -f $@
objects="$(objects)"; \
@@ -905,7 +917,7 @@ libgcc.a libgcov.a libunwind.a libgcc_eh.a:
$(RANLIB) $@
-all: libgcc.a libgcov.a
+all: libgcc.a libgcc_nonshared.a libgcov.a
ifneq ($(LIBUNWIND),)
all: libunwind.a
@@ -1051,6 +1063,7 @@ libgcc-extra-parts: $(EXTRA_PARTS)
all: $(extra-parts)
$(libgcc-objects) $(libgcc-s-objects) $(libgcc-eh-objects) \
+ $(libgcc-nonshared-objects) \
$(libgcov-objects) \
$(libunwind-objects) $(libunwind-s-objects) \
$(EXTRA_PARTS): libgcc_tm.h
@@ -1118,6 +1131,9 @@ install-leaf: $(install-shared) $(install-libunwind)
$(INSTALL_DATA) libgcc.a $(DESTDIR)$(inst_libdir)/
chmod 644 $(DESTDIR)$(inst_libdir)/libgcc.a
$(RANLIB) $(DESTDIR)$(inst_libdir)/libgcc.a
+ $(INSTALL_DATA) libgcc_nonshared.a $(DESTDIR)$(inst_libdir)/
+ chmod 644 $(DESTDIR)$(inst_libdir)/libgcc_nonshared.a
+ $(RANLIB) $(DESTDIR)$(inst_libdir)/libgcc_nonshared.a
$(INSTALL_DATA) libgcov.a $(DESTDIR)$(inst_libdir)/
chmod 644 $(DESTDIR)$(inst_libdir)/libgcov.a
$(RANLIB) $(DESTDIR)$(inst_libdir)/libgcov.a
diff --git a/libgcc/config/i386/cpuinfo.c b/libgcc/config/i386/cpuinfo.c
index eaf2f10..f6f91dd 100644
--- a/libgcc/config/i386/cpuinfo.c
+++ b/libgcc/config/i386/cpuinfo.c
@@ -109,7 +109,7 @@ struct __processor_model
unsigned int __cpu_type;
unsigned int __cpu_subtype;
unsigned int __cpu_features[1];
-} __cpu_model;
+} __cpu_model = { };
/* Get the specific type of AMD CPU. */
@@ -424,3 +424,8 @@ __cpu_indicator_init (void)
return 0;
}
+
+#if defined SHARED && defined USE_ELF_SYMVER
+__asm__ (".symver __cpu_indicator_init, __cpu_indicator_init@GCC_4.8.0");
+__asm__ (".symver __cpu_model, __cpu_model@GCC_4.8.0");
+#endif
diff --git a/libgcc/config/i386/t-cpuinfo b/libgcc/config/i386/t-cpuinfo
index 31c8db9..b20ef30 100644
--- a/libgcc/config/i386/t-cpuinfo
+++ b/libgcc/config/i386/t-cpuinfo
@@ -1 +1,2 @@
LIB2ADD += $(srcdir)/config/i386/cpuinfo.c
+LIB2ADDNONSHARED += $(srcdir)/config/i386/cpuinfo.c
diff --git a/libgcc/config/i386/t-linux b/libgcc/config/i386/t-linux
index 4f47f7b..11bb46e 100644
--- a/libgcc/config/i386/t-linux
+++ b/libgcc/config/i386/t-linux
@@ -3,4 +3,4 @@
# t-slibgcc-elf-ver and t-linux
SHLIB_MAPFILES = libgcc-std.ver $(srcdir)/config/i386/libgcc-glibc.ver
-HOST_LIBGCC2_CFLAGS += -mlong-double-80
+HOST_LIBGCC2_CFLAGS += -mlong-double-80 -DUSE_ELF_SYMVER
diff --git a/libgcc/shared-object.mk b/libgcc/shared-object.mk
index efac797..306176d 100644
--- a/libgcc/shared-object.mk
+++ b/libgcc/shared-object.mk
@@ -4,6 +4,7 @@
o := $(firstword $(iter-items))
iter-items := $(filter-out $o,$(iter-items))
+ifneq ($o,)
base := $(basename $(notdir $o))
c_flags-$o := $(c_flags)
@@ -36,3 +37,4 @@ $(base)_s$(objext): $o
$(gcc_s_compile) -c $(as_flags-$<) $<
endif
+endif
--
1.9.3