diff mbox

PATCH] PR target/65612: Multiversioning doesn't work with DSO nor PIE

Message ID CAMe9rOrm=9gkqjFwEX8GVtri3t2mSmgOqfm_Q+LizCJqbLSAKQ@mail.gmail.com
State New
Headers show

Commit Message

H.J. Lu March 31, 2015, 10:38 a.m. UTC
On Mon, Mar 30, 2015 at 10:38 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> On Mon, Mar 30, 2015 at 07:08:00PM -0700, H.J. Lu wrote:
>> --- a/gcc/gcc.c
>> +++ b/gcc/gcc.c
>> @@ -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"
>
> Why do you need to link libgcc_nonshared.a twice here?  -lgcc_s surely won't
> add any new __cpu* undefined references.

The one added for -lgcc_s is for building shared C++ library since -lgcc isn't
used and only -lgcc_s is used.  The one added for -lgcc is for static linking
since -lgcc_s isn't used.  I updated the patch to add some testcases
for -static.
I couldn't find a way to add tests for:

export/build/gnu/gcc/build-x86_64-linux/gcc/xg++
-B/export/build/gnu/gcc/build-x86_64-linux/gcc/ -O2    -c -o main.o
main.cc
/export/build/gnu/gcc/build-x86_64-linux/gcc/xg++
-B/export/build/gnu/gcc/build-x86_64-linux/gcc/ -shared -fPIC -O2  -o
libmv20.so mv20.cc
-L/export/build/gnu/gcc/build-x86_64-linux/x86_64-unknown-linux-gnu/libstdc++-v3/src/.libs
/export/build/gnu/gcc/build-x86_64-linux/gcc/xg++
-B/export/build/gnu/gcc/build-x86_64-linux/gcc/ -O2  -o x main.o
libmv20.so -Wl,-R,.
-L/export/build/gnu/gcc/build-x86_64-linux/x86_64-unknown-linux-gnu/libstdc++-v3/src/.libs
/usr/local/bin/ld: x: hidden symbol `__cpu_model' in
/export/build/gnu/gcc/build-x86_64-linux/gcc/libgcc_nonshared.a(cpuinfo.o)
is referenced by DSO
/usr/local/bin/ld: final link failed: Bad value
collect2: error: ld returned 1 exit status

>> @@ -424,3 +424,8 @@ __cpu_indicator_init (void)
>>
>>    return 0;
>>  }
>> +
>> +#if defined SHARED && !defined _WIN32
>> +__asm__ (".symver __cpu_indicator_init, __cpu_indicator_init@GCC_4.8.0");
>> +__asm__ (".symver __cpu_model, __cpu_model@GCC_4.8.0");
>> +#endif
>
> Will this work on Solaris?
> I'd say you at least want to also guard with some configure check if
> .symver is supported by assembler.
>

I updated my patch with:

@@ -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


OK for master?
diff mbox

Patch

From 259457afe0add56064ed49da1954d0770b1e1975 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/-lgcc/libgcc.a%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 (LIB2ADDSHARED): New.
	(LIB2ADDNONSHARED): Likewise.
	(libgcc-nonshared-objects): Likewise.
	(libgcc_nonshared.a): Likewise.
	Check unsupported files in LIB2ADDNONSHARED or LIB2ADDSHARED.
	(iter-items): Add $(LIB2ADDNONSHARED) $(LIB2ADDSHARED).
	(libgcc-s-objects): Add $(LIB2ADDSHARED).
	(all): Depend on libgcc_nonshared.a.
	($(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 (LIB2ADD): Renamed to ...
	(LIB2ADDSHARED): This.
	(LIB2ADDNONSHARED): New.
	* config/i386/t-linux (HOST_LIBGCC2_CFLAGS): Add
	-DUSE_ELF_SYMVER.
---
 gcc/gcc.c                       |  4 ++++
 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              | 28 ++++++++++++++++++++++++----
 libgcc/config/i386/cpuinfo.c    |  7 ++++++-
 libgcc/config/i386/t-cpuinfo    |  3 ++-
 libgcc/config/i386/t-linux      |  2 +-
 libgcc/shared-object.mk         |  2 ++
 12 files changed, 81 insertions(+), 7 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..88a8dac 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -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"
 #ifdef USE_LIBUNWIND_EXCEPTIONS
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..f6eb047 100644
--- a/libgcc/Makefile.in
+++ b/libgcc/Makefile.in
@@ -261,6 +261,14 @@  LIB2ADD =
 # Assembler files should have names ending in `.S'.
 LIB2ADD_ST =
 
+# List of extra C and assembler files to add to shared libgcc2.
+# Assembler files should have names ending in `.S'.
+LIB2ADDSHARED =
+
+# 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
@@ -807,12 +815,19 @@  endif
 libgcc-objects += $(addsuffix $(objext),$(basename $(notdir $(LIB2ADD))))
 libgcc-objects += $(addsuffix $(objext),$(basename $(notdir $(LIB2ADD_ST))))
 
+# Build LIB2ADDNONSHARED and LIB2ADDSHARED.
+ifneq ($(filter-out %.c %.S %.asm,$(LIB2ADDNONSHARED) $(LIB2ADDSHARED)),)
+$(error Unsupported files in LIB2ADDNONSHARED or LIB2ADDSHARED.)
+endif
+
+libgcc-nonshared-objects += $(addsuffix $(objext),$(basename $(notdir $(LIB2ADDNONSHARED))))
+
 c_flags :=
-iter-items := $(LIB2ADD) $(LIB2ADD_ST)
+iter-items := $(LIB2ADD) $(LIB2ADD_ST) $(LIB2ADDNONSHARED) $(LIB2ADDSHARED)
 include $(iterator)
 
 ifeq ($(enable_shared),yes)
-libgcc-s-objects += $(addsuffix _s$(objext),$(basename $(notdir $(LIB2ADD))))
+libgcc-s-objects += $(addsuffix _s$(objext),$(basename $(notdir $(LIB2ADD) $(LIB2ADDSHARED))))
 endif
 
 # Build LIB2ADDEH, LIB2ADDEHSTATIC, and LIB2ADDEHSHARED.  If we don't have
@@ -890,8 +905,9 @@  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 +921,7 @@  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 +1067,7 @@  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 +1135,9 @@  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..8dbe9e6 100644
--- a/libgcc/config/i386/t-cpuinfo
+++ b/libgcc/config/i386/t-cpuinfo
@@ -1 +1,2 @@ 
-LIB2ADD += $(srcdir)/config/i386/cpuinfo.c
+LIB2ADDSHARED += $(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
-- 
2.1.0