diff options
author | Jakub Jelinek <jakub@redhat.com> | 2023-04-28 10:49:40 +0200 |
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committer | Jakub Jelinek <jakub@redhat.com> | 2023-04-28 10:49:40 +0200 |
commit | 9a41d2cdbcd2af77a3a91a840a3a13f0eb39971b (patch) | |
tree | 08da1fc2a41f85039f21fb63886d2254c4d1b788 /libstdc++-v3 | |
parent | 889a0791c632aa2804c4e01cc7dddca1ae0d229c (diff) | |
download | gcc-9a41d2cdbcd2af77a3a91a840a3a13f0eb39971b.tar.gz |
libstdc++: Another attempt to ensure g++ 13+ compiled programs enforce gcc 13.2+ libstdc++.so.6 [PR108969]
GCC used to emit an instance of an empty ios_base::Init class in
every TU which included <iostream> to ensure it is std::cout etc.
is initialized, but thanks to Patrick work on some targets (which have
init_priority attribute support) it is now initialized only inside of
libstdc++.so.6/libstdc++.a.
This causes a problem if people do something that has never been supported,
try to run GCC 13 compiled C++ code against GCC 12 or earlier
libstdc++.so.6 - std::cout etc. are then never initialized because code
including <iostream> expects the library to initialize it and the library
expects code including <iostream> to do that.
The following patch is second attempt to make this work cheaply as the
earlier attempt of aliasing the std::cout etc. symbols with another symbol
version didn't work out due to copy relocation breaking the aliases appart.
The patch forces just a _ZSt21ios_base_library_initv undefined symbol
into all *.o files which include <iostream> and while there is no runtime
relocation against that, it seems to enforce the right version of
libstdc++.so.6. /home/jakub/src/gcc/obj08i/usr/local/ is the install
directory of trunk patched with this patch, /home/jakub/src/gcc/obj06/
is builddir of trunk without this patch, system g++ is GCC 12.1.1.
$ cat /tmp/hw.C
#include <iostream>
int
main ()
{
std::cout << "Hello, world!" << std::endl;
}
$ cd /home/jakub/src/gcc/obj08i/usr/local/bin
$ ./g++ -o /tmp/hw /tmp/hw.C
$ readelf -Wa /tmp/hw 2>/dev/null | grep initv
4: 0000000000000000 0 FUNC GLOBAL DEFAULT UND _ZSt21ios_base_library_initv@GLIBCXX_3.4.32 (4)
71: 0000000000000000 0 FUNC GLOBAL DEFAULT UND _ZSt21ios_base_library_initv@GLIBCXX_3.4.32
$ /tmp/hw
/tmp/hw: /lib64/libstdc++.so.6: version `GLIBCXX_3.4.32' not found (required by /tmp/hw)
$ LD_LIBRARY_PATH=/home/jakub/src/gcc/obj08i/usr/local/lib64/ /tmp/hw
Hello, world!
$ LD_LIBRARY_PATH=/home/jakub/src/gcc/obj06/x86_64-pc-linux-gnu/libstdc++-v3/src/.libs/ /tmp/hw
/tmp/hw: /home/jakub/src/gcc/obj06/x86_64-pc-linux-gnu/libstdc++-v3/src/.libs/libstdc++.so.6: version `GLIBCXX_3.4.32' not found (required by /tmp/hw)
$ g++ -o /tmp/hw /tmp/hw.C
$ /tmp/hw
Hello, world!
$ LD_LIBRARY_PATH=/home/jakub/src/gcc/obj06/x86_64-pc-linux-gnu/libstdc++-v3/src/.libs/ /tmp/hw
Hello, world!
$ LD_LIBRARY_PATH=/home/jakub/src/gcc/obj08i/usr/local/lib64/ /tmp/hw
Hello, world!
On sparc-sun-solaris2.11 one I've actually checked a version which had
defined(_GLIBCXX_SYMVER_SUN) next to defined(_GLIBCXX_SYMVER_GNU), but
init_priority attribute doesn't seem to be supported there and so I couldn't
actually test how this works there. Using gas and Sun ld, Rainer, does one
need to use gas + gld for init_priority or something else?
2023-04-28 Jakub Jelinek <jakub@redhat.com>
PR libstdc++/108969
* config/abi/pre/gnu.ver (GLIBCXX_3.4.32): Export
_ZSt21ios_base_library_initv.
* testsuite/util/testsuite_abi.cc (check_version): Add GLIBCXX_3.4.32
symver and make it the latestp.
* src/c++98/ios_init.cc (ios_base_library_init): New alias.
* acinclude.m4 (libtool_VERSION): Change to 6:32:0.
* include/std/iostream: If init_priority attribute is supported
and _GLIBCXX_SYMVER_GNU, force undefined _ZSt21ios_base_library_initv
symbol into the object.
* configure: Regenerated.
Diffstat (limited to 'libstdc++-v3')
-rw-r--r-- | libstdc++-v3/acinclude.m4 | 2 | ||||
-rw-r--r-- | libstdc++-v3/config/abi/pre/gnu.ver | 4 | ||||
-rwxr-xr-x | libstdc++-v3/configure | 2 | ||||
-rw-r--r-- | libstdc++-v3/include/std/iostream | 2 | ||||
-rw-r--r-- | libstdc++-v3/src/c++98/ios_init.cc | 5 | ||||
-rw-r--r-- | libstdc++-v3/testsuite/util/testsuite_abi.cc | 3 |
6 files changed, 15 insertions, 3 deletions
diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4 index 5136c0571e8..89e7f5f5f45 100644 --- a/libstdc++-v3/acinclude.m4 +++ b/libstdc++-v3/acinclude.m4 @@ -3841,7 +3841,7 @@ changequote([,])dnl fi # For libtool versioning info, format is CURRENT:REVISION:AGE -libtool_VERSION=6:31:0 +libtool_VERSION=6:32:0 # Everything parsed; figure out what files and settings to use. case $enable_symvers in diff --git a/libstdc++-v3/config/abi/pre/gnu.ver b/libstdc++-v3/config/abi/pre/gnu.ver index 4ae63094eb7..36bb87880d7 100644 --- a/libstdc++-v3/config/abi/pre/gnu.ver +++ b/libstdc++-v3/config/abi/pre/gnu.ver @@ -2514,6 +2514,10 @@ GLIBCXX_3.4.31 { } GLIBCXX_3.4.30; +GLIBCXX_3.4.32 { + _ZSt21ios_base_library_initv; +} GLIBCXX_3.4.31; + # Symbols in the support library (libsupc++) have their own tag. CXXABI_1.3 { diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure index 68ee94c9e28..99f4927aa8c 100755 --- a/libstdc++-v3/configure +++ b/libstdc++-v3/configure @@ -68652,7 +68652,7 @@ $as_echo "$as_me: WARNING: === Symbol versioning will be disabled." >&2;} fi # For libtool versioning info, format is CURRENT:REVISION:AGE -libtool_VERSION=6:31:0 +libtool_VERSION=6:32:0 # Everything parsed; figure out what files and settings to use. case $enable_symvers in diff --git a/libstdc++-v3/include/std/iostream b/libstdc++-v3/include/std/iostream index 76530029b86..cfd124dcf43 100644 --- a/libstdc++-v3/include/std/iostream +++ b/libstdc++-v3/include/std/iostream @@ -77,6 +77,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION // in the compiled library instead (src/c++98/globals_io.cc). #if !__has_attribute(__init_priority__) static ios_base::Init __ioinit; +#elif defined(_GLIBCXX_SYMVER_GNU) + __extension__ __asm (".globl _ZSt21ios_base_library_initv"); #endif _GLIBCXX_END_NAMESPACE_VERSION diff --git a/libstdc++-v3/src/c++98/ios_init.cc b/libstdc++-v3/src/c++98/ios_init.cc index 6b43a6bf563..0c2ba945f36 100644 --- a/libstdc++-v3/src/c++98/ios_init.cc +++ b/libstdc++-v3/src/c++98/ios_init.cc @@ -199,5 +199,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION return __ret; } +#ifdef _GLIBCXX_SYMVER_GNU + void ios_base_library_init (void) + __attribute__((alias ("_ZNSt8ios_base4InitC1Ev"))); +#endif + _GLIBCXX_END_NAMESPACE_VERSION } // namespace diff --git a/libstdc++-v3/testsuite/util/testsuite_abi.cc b/libstdc++-v3/testsuite/util/testsuite_abi.cc index 5b7d0435110..cea6c217433 100644 --- a/libstdc++-v3/testsuite/util/testsuite_abi.cc +++ b/libstdc++-v3/testsuite/util/testsuite_abi.cc @@ -213,6 +213,7 @@ check_version(symbol& test, bool added) known_versions.push_back("GLIBCXX_LDBL_3.4.29"); known_versions.push_back("GLIBCXX_3.4.30"); known_versions.push_back("GLIBCXX_3.4.31"); + known_versions.push_back("GLIBCXX_3.4.32"); known_versions.push_back("GLIBCXX_LDBL_3.4.31"); known_versions.push_back("GLIBCXX_IEEE128_3.4.29"); known_versions.push_back("GLIBCXX_IEEE128_3.4.30"); @@ -251,7 +252,7 @@ check_version(symbol& test, bool added) test.version_status = symbol::incompatible; // Check that added symbols are added in the latest pre-release version. - bool latestp = (test.version_name == "GLIBCXX_3.4.31" + bool latestp = (test.version_name == "GLIBCXX_3.4.32" // XXX remove next 2 lines when baselines have been regenerated. || test.version_name == "GLIBCXX_IEEE128_3.4.31" || test.version_name == "GLIBCXX_LDBL_3.4.31" |