| Message ID | 20150330022527.GA4148@gmail.com |
|---|---|
| State | New |
| Headers | show |
On Sun, Mar 29, 2015 at 7:25 PM, H.J. Lu <hjl.tools@gmail.com> wrote: > 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.a while providing backward binary compatibility. > > OK for trunk, 4.9 and 4.9 branches? > > Thanks. > > > H.J. > --- > libgcc/ > > PR target/65612 > * config/i386/cpuinfo.c (__cpu_model): Initialize. > (__cpu_indicator_init@GCC_4.8.0): New. > (__cpu_model@GCC_4.8.0): Likewise. > > gcc/testsuite/ > > PR target/65612 > * g++.dg/ext/mv18.C: New test. > * g++.dg/ext/mv19.C: Likewise. > * g++.dg/ext/mv20.C: Likewise. It doesn' work for shared C++ library: /export/build/gnu/gcc-x32/release/usr/gcc-5.0.0-x32/bin/g++ -O2 -c -o main.o main.cc /export/build/gnu/gcc-x32/release/usr/gcc-5.0.0-x32/bin/g++ -shared -fPIC -O2 -o libmv20.so mv20.cc /export/build/gnu/gcc-x32/release/usr/gcc-5.0.0-x32/bin/g++ -O2 -o x main.o libmv20.so -Wl,-R,. /usr/local/bin/ld: x: hidden symbol `__cpu_model' in /export/build/gnu/gcc-x32/release/usr/gcc-5.0.0-x32/bin/../lib/gcc/x86_64-unknown-linux-gnu/5.0.0/libgcc.a(cpuinfo.o) is referenced by DSO /usr/local/bin/ld: final link failed: Bad value collect2: error: ld returned 1 exit status Makefile:12: recipe for target 'x' failed make: *** [x] Error 1 [hjl@gnu-tools-1 pr65612]$
On Sun, Mar 29, 2015 at 7:34 PM, H.J. Lu <hjl.tools@gmail.com> wrote: > On Sun, Mar 29, 2015 at 7:25 PM, H.J. Lu <hjl.tools@gmail.com> wrote: >> 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.a while providing backward binary compatibility. >> >> OK for trunk, 4.9 and 4.9 branches? >> >> Thanks. >> >> >> H.J. >> --- >> libgcc/ >> >> PR target/65612 >> * config/i386/cpuinfo.c (__cpu_model): Initialize. >> (__cpu_indicator_init@GCC_4.8.0): New. >> (__cpu_model@GCC_4.8.0): Likewise. >> >> gcc/testsuite/ >> >> PR target/65612 >> * g++.dg/ext/mv18.C: New test. >> * g++.dg/ext/mv19.C: Likewise. >> * g++.dg/ext/mv20.C: Likewise. > > It doesn' work for shared C++ library: > > /export/build/gnu/gcc-x32/release/usr/gcc-5.0.0-x32/bin/g++ -O2 -c > -o main.o main.cc > /export/build/gnu/gcc-x32/release/usr/gcc-5.0.0-x32/bin/g++ -shared > -fPIC -O2 -o libmv20.so mv20.cc > /export/build/gnu/gcc-x32/release/usr/gcc-5.0.0-x32/bin/g++ -O2 -o x > main.o libmv20.so -Wl,-R,. > /usr/local/bin/ld: x: hidden symbol `__cpu_model' in > /export/build/gnu/gcc-x32/release/usr/gcc-5.0.0-x32/bin/../lib/gcc/x86_64-unknown-linux-gnu/5.0.0/libgcc.a(cpuinfo.o) > is referenced by DSO > /usr/local/bin/ld: final link failed: Bad value > collect2: error: ld returned 1 exit status > Makefile:12: recipe for target 'x' failed > make: *** [x] Error 1 > [hjl@gnu-tools-1 pr65612]$ > > -- > H.J. We need something like libgcc_nonshared.a, which contains cpuinfo.o, and link together with -lgcc_s when creating executable or DSO.
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/libgcc/config/i386/cpuinfo.c b/libgcc/config/i386/cpuinfo.c index eaf2f10..9639c8d 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 _WIN32 +__asm__ (".symver __cpu_indicator_init, __cpu_indicator_init@GCC_4.8.0"); +__asm__ (".symver __cpu_model, __cpu_model@GCC_4.8.0"); +#endif