Hide private symbols in shared library

[rhubner]

Add new build flag HIDE_PRIVATE_SYMBOLS to allow compile shared library without exported private symbols.

Work only in Release mode.

Fix #12929

[ottok]

I tested this in https://salsa.debian.org/debian/rocksdb/-/merge_requests/3 and it didn't work. I wonder did I enable the flag and 'Release mode' correctly?

...
+ _ZZNSt19_Sp_make_shared_tag5_S_tiEvE5__tag@Base 9.3.1-1
+ _ZZNSt6vectorIN7rocksdb12FileMetaDataESaIS1_EE17_M_realloc_appendIJRKS1_EEEvDpOT_EN11_Guard_eltsD1Ev@Base 9.3.1-1
+ _ZZNSt6vectorIN7rocksdb12FileMetaDataESaIS1_EE17_M_realloc_appendIJRKS1_EEEvDpOT_EN11_Guard_eltsD2Ev@Base 9.3.1-1
+ _ZZNSt6vectorIN7rocksdb13LevelMetaDataESaIS1_EE17_M_realloc_appendIJRiRmS_INS0_15SstFileMetaDataESaIS7_EEEEEvDpOT_EN11_Guard_eltsD1Ev@Base 9.3.1-1
+ _ZZNSt6vectorIN7rocksdb13LevelMetaDataESaIS1_EE17_M_realloc_appendIJRiRmS_INS0_15SstFileMetaDataESaIS7_EEEEEvDpOT_EN11_Guard_eltsD2Ev@Base 9.3.1-1
+ _ZZNSt6vectorIN7rocksdb16IngestedFileInfoESaIS1_EE17_M_realloc_appendIJRKS1_EEEvDpOT_EN11_Guard_eltsD1Ev@Base 9.3.1-1
+ _ZZNSt6vectorIN7rocksdb16IngestedFileInfoESaIS1_EE17_M_realloc_appendIJRKS1_EEEvDpOT_EN11_Guard_eltsD2Ev@Base 9.3.1-1
+ _ZZNSt6vectorIN7rocksdb16IngestedFileInfoESaIS1_EE17_M_realloc_appendIJS1_EEEvDpOT_EN11_Guard_eltsD1Ev@Base 9.3.1-1
+ _ZZNSt6vectorIN7rocksdb16IngestedFileInfoESaIS1_EE17_M_realloc_appendIJS1_EEEvDpOT_EN11_Guard_eltsD2Ev@Base 9.3.1-1
+ _ZZNSt6vectorIN7rocksdb17CompactionOutputs6OutputESaIS2_EE17_M_realloc_appendIJNS0_12FileMetaDataERKNS0_21InternalKeyComparatorERbSA_RmEEEvDpOT_EN11_Guard_eltsD1Ev@Base 9.3.1-1
+ _ZZNSt6vectorIN7rocksdb17CompactionOutputs6OutputESaIS2_EE17_M_realloc_appendIJNS0_12FileMetaDataERKNS0_21InternalKeyComparatorERbSA_RmEEEvDpOT_EN11_Guard_eltsD2Ev@Base 9.3.1-1
+ _ZZNSt6vectorISt4pairIiN7rocksdb12FileMetaDataEESaIS3_EE17_M_realloc_appendIJRiRKS2_EEEvDpOT_EN11_Guard_eltsD1Ev@Base 9.3.1-1
+ _ZZNSt6vectorISt4pairIiN7rocksdb12FileMetaDataEESaIS3_EE17_M_realloc_appendIJRiRKS2_EEEvDpOT_EN11_Guard_eltsD2Ev@Base 9.3.1-1
+ _ZZNSt6vectorISt4pairIiN7rocksdb12FileMetaDataEESaIS3_EE17_M_realloc_appendIJRiS2_EEEvDpOT_EN11_Guard_eltsD1Ev@Base 9.3.1-1
+ _ZZNSt6vectorISt4pairIiN7rocksdb12FileMetaDataEESaIS3_EE17_M_realloc_appendIJRiS2_EEEvDpOT_EN11_Guard_eltsD2Ev@Base 9.3.1-1
+ _ZZNSt6vectorISt4pairIiN7rocksdb12FileMetaDataEESaIS3_EE17_M_realloc_appendIJS3_EEEvDpOT_EN11_Guard_eltsD1Ev@Base 9.3.1-1
+ _ZZNSt6vectorISt4pairIiN7rocksdb12FileMetaDataEESaIS3_EE17_M_realloc_appendIJS3_EEEvDpOT_EN11_Guard_eltsD2Ev@Base 9.3.1-1
+ _ZZNSt9once_flag18_Prepare_executionC4IZSt9call_onceIMNSt13__future_base13_State_baseV2EFvPSt8functionIFSt10unique_ptrINS3_12_Result_baseENS7_8_DeleterEEvEEPbEJPS4_SC_SD_EEvRS_OT_DpOT0_EUlvE_EERSI_ENUlvE_4_FUNEv@Base 9.3.1-1
...

[ottok]

More info on how Debian scans the ABI:

• https://manpages.debian.org/unstable/dpkg-dev/dpkg-gensymbols.1.en.html
• https://manpages.debian.org/unstable/dpkg-dev/deb-symbols.5.en.html

[rhubner]

Hello @ottok,

thanks for quick reply. I think we need to update CMake parameters. This is what I found in your build system :

cmake -DCMAKE_INSTALL_PREFIX=/usr -DCMAKE_BUILD_TYPE=None -DCMAKE_INSTALL_SYSCONFDIR=/etc -DCMAKE_INSTALL_LOCALSTATEDIR=/var -DCMAKE_EXPORT_NO_PACKAGE_REGISTRY=ON -DCMAKE_FIND_USE_PACKAGE_REGISTRY=OFF -DCMAKE_FIND_PACKAGE_NO_PACKAGE_REGISTRY=ON -DFETCHCONTENT_FULLY_DISCONNECTED=ON -DCMAKE_INSTALL_RUNSTATEDIR=/run -DCMAKE_SKIP_INSTALL_ALL_DEPENDENCY=ON "-GUnix Makefiles" -DCMAKE_VERBOSE_MAKEFILE=ON -DCMAKE_INSTALL_LIBDIR=lib/x86_64-linux-gnu -DWITH_BZ2=ON -DWITH_LZ4=ON -DWITH_ZLIB=ON -DWITH_ZSTD=ON -DWITH_SNAPPY=ON -DROCKSDB_BUILD_SHARED=ON -DWITH_BENCHMARK_TOOLS=ON -DWITH_CORE_TOOLS=ON -DWITH_TOOLS=ON -DWITH_TESTS=ON -DPORTABLE=1 -DHIDE_PRIVATE_SYMBOLS=1 -DFAIL_ON_WARNINGS=OFF ..

I think the problem is -DCMAKE_BUILD_TYPE=None. Try to change to -DCMAKE_BUILD_TYPE=Release.

Radek

[ottok]

I applied -DCMAKE_BUILD_TYPE=Release in https://salsa.debian.org/debian/rocksdb/-/merge_requests/3 and now build fails with:

/usr/bin/ld: CMakeFiles/db_bench.dir/tools/db_bench_tool.cc.o:(.data.rel.ro._ZTVN7rocksdb9Benchmark10KeepFilterE[_ZTVN7rocksdb9Benchmark10KeepFilterE]+0x28): undefined reference to `rocksdb::Customizable::AreEquivalent(rocksdb::ConfigOptions const&, rocksdb::Configurable const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*) const'
/usr/bin/ld: CMakeFiles/db_bench.dir/tools/db_bench_tool.cc.o:(.data.rel.ro._ZTVN7rocksdb9Benchmark10KeepFilterE[_ZTVN7rocksdb9Benchmark10KeepFilterE]+0x38): undefined reference to `rocksdb::Configurable::PrepareOptions(rocksdb::ConfigOptions const&)'
/usr/bin/ld: CMakeFiles/db_bench.dir/tools/db_bench_tool.cc.o:(.data.rel.ro._ZTVN7rocksdb9Benchmark10KeepFilterE[_ZTVN7rocksdb9Benchmark10KeepFilterE]+0x40): undefined reference to `rocksdb::Configurable::ValidateOptions(rocksdb::DBOptions const&, rocksdb::ColumnFamilyOptions const&) const'
/usr/bin/ld: CMakeFiles/db_bench.dir/tools/db_bench_tool.cc.o:(.data.rel.ro._ZTVN7rocksdb9Benchmark10KeepFilterE[_ZTVN7rocksdb9Benchmark10KeepFilterE]+0x50): undefined reference to `rocksdb::Configurable::ParseStringOptions(rocksdb::ConfigOptions const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
/usr/bin/ld: CMakeFiles/db_bench.dir/tools/db_bench_tool.cc.o:(.data.rel.ro._ZTVN7rocksdb9Benchmark10KeepFilterE[_ZTVN7rocksdb9Benchmark10KeepFilterE]+0x58): undefined reference to `rocksdb::Configurable::ConfigureOptions(rocksdb::ConfigOptions const&, std::unordered_map<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::hash<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::equal_to<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > > const&, std::unordered_map<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::hash<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::equal_to<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >*)'
/usr/bin/ld: CMakeFiles/db_bench.dir/tools/db_bench_tool.cc.o:(.data.rel.ro._ZTVN7rocksdb9Benchmark10KeepFilterE[_ZTVN7rocksdb9Benchmark10KeepFilterE]+0x60): undefined reference to `rocksdb::Configurable::ParseOption(rocksdb::ConfigOptions const&, rocksdb::OptionTypeInfo const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, void*)'
/usr/bin/ld: CMakeFiles/db_bench.dir/tools/db_bench_tool.cc.o:(.data.rel.ro._ZTVN7rocksdb9Benchmark10KeepFilterE[_ZTVN7rocksdb9Benchmark10KeepFilterE]+0x68): undefined reference to `rocksdb::Configurable::OptionsAreEqual(rocksdb::ConfigOptions const&, rocksdb::OptionTypeInfo const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, void const*, void const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*) const'
/usr/bin/ld: CMakeFiles/db_bench.dir/tools/db_bench_tool.cc.o:(.data.rel.ro._ZTVN7rocksdb9Benchmark10KeepFilterE[_ZTVN7rocksdb9Benchmark10KeepFilterE]+0x70): undefined reference to `rocksdb::Customizable::SerializeOptions(rocksdb::ConfigOptions const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) const'
/usr/bin/ld: CMakeFiles/db_bench.dir/tools/db_bench_tool.cc.o:(.data.rel.ro._ZTVN7rocksdb9Benchmark10KeepFilterE[_ZTVN7rocksdb9Benchmark10KeepFilterE]+0x78): undefined reference to `rocksdb::Customizable::GetOptionName(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) const'
/usr/bin/ld: CMakeFiles/db_bench.dir/tools/db_bench_tool.cc.o:(.data.rel.ro+0x0): undefined reference to `vtable for rocksdb::BlockCacheTierMetadata'
/usr/bin/ld: warning: creating DT_TEXTREL in a PIE
collect2: error: ld returned 1 exit status
make[3]: *** [CMakeFiles/db_bench.dir/build.make:139: db_bench] Error 1
make[3]: Leaving directory '/tmp/build/source/obj-x86_64-linux-gnu'
make[2]: *** [CMakeFiles/Makefile2:254: CMakeFiles/db_bench.dir/all] Error 2
make[2]: Leaving directory '/tmp/build/source/obj-x86_64-linux-gnu'
make[1]: *** [Makefile:139: all] Error 2
make[1]: Leaving directory '/tmp/build/source/obj-x86_64-linux-gnu'
dh_auto_build: error: cd obj-x86_64-linux-gnu && make -j4 "INSTALL=install --strip-program=true" VERBOSE=1 returned exit code 2
make: *** [debian/rules:60: binary] Error 2

Seems now that the linker still sees the private symbols and fails to compute as they have become hidden..?

[rhubner]

Hello @ottok,

thanks for quick reply. It looks like this will be bigger problem. As you suggested I hide all symbols except C API. But as you can see, other program are using also C++ API. I don't know how to efficiently export only the public symbols and hide others.

I'm able to compile librocksdb.so with thees flags : -DWITH_TESTS=OFF -DWITH_BENCHMARK_TOOLS=OFF -DWITH_TOOLS=OFF and then make rocksdb. But then it may not have some C++ API. 🤔

I think this will need more refactoring across RocksDB codebase to define which classes/structs/methods are public API and what is private.

cc: @adamretter: What are your thoughts?

Radek

[ottok]

Thanks for looking into this and considering refactoring! RocksDB does not strictly require this, but it would be good engineering practice to have clear separation of private and public symbols as it decreases the chance of bugs and makes long-term maintenance and upgrades of the library easier and less likely to have unexpected breakage with consuming software. Both Debian and Fedora care about ABI symbols and tracking them.