libunwind is reentrant and signal safe, and works faster then then
gcc_eh (plus it has some custom patches for problems that have been
found during it's usage in ClickHouse).
gcc_eh may be missing in the system (if gcc was not installed), and
even if it exists clickhouse uses -nodefaultlibs, so some care should be
made to make it work.
Also this library is tiny and there shouln't be any problem to require
it always (there is already tendency to require some contrib libraries,
i.e. poco).
Signed-off-by: Azat Khuzhin <a.khuzhin@semrush.com>
Cross-compiling on Linux for Mac failed with CMake parameters
-DCMAKE_BUILD_TYPE=None -DENABLE_CLICKHOUSE_SELF_EXTRACTING=1
-DENABLE_TESTS=0 (see below). This happened e.g. in #51243.
The problem was that ThinLTO enabled/disabled depends on ENABLE_TESTS
(see the top-level CMakeLists.txt). If ENABLE_TESTS=0 then ThinLTO is
activated. On Linux, building/linking works with or without ThinLTO but
on Mac building/linking the self-extracting compressor binary doesn’t
work if ThinLTO is on. This is quite weird, as a workaround restrict
ThinLTO to Linux.
-------
[185/187] Linking CXX static library base/glibc-compatibility/libglibc-compatibility.a
[186/187] Linking CXX static library contrib/zstd-cmake/lib_zstd.a
[187/187] Linking CXX executable utils/self-extracting-executable/pre_compressor
-- Configuring done
-- Generating done
-- Build files have been written to: /home/ubuntu/repo/ch4/build
[0/2] Re-checking globbed directories...
[108/108] Linking CXX executable utils/self-extracting-executable/pre_compressor
FAILED: utils/self-extracting-executable/pre_compressor
: && /usr/bin/clang++-16 --target=x86_64-apple-darwin -std=c++20 -fdiagnostics-color=always -Xclang -fuse-ctor-homing -Wno-enum-constexpr-conversion -fsized-deallocation -gdwarf-aranges -pipe -mssse3 -msse4.1 -msse4.2 -mpclmul -mpopcnt -fasynchronous-unwind-tables -ffile-prefix-map=/home/ubuntu/repo/ch4=. -falign-functions=32 -mbranches-within-32B-boundaries -stdlib=libc++ -fdiagnostics-absolute-paths -fstrict
-vtable-pointers -Wall -Wextra -Wframe-larger-than=65536 -Weverything -Wpedantic -Wno-zero-length-array -Wno-c++98-compat-pedantic -Wno-c++98-compat -Wno-c++20-compat -Wno-sign-conversion -Wno-implicit-int-conversion -Wno-implicit-int-float-conversion -Wno-ctad-maybe-unsupported -Wno-disabled-macro-expansion -Wno-documentation-unknown-command -Wno-double-promotion -Wno-exit-time-destructors -Wno-float-equal -Wn
o-global-constructors -Wno-missing-prototypes -Wno-missing-variable-declarations -Wno-padded -Wno-switch-enum -Wno-undefined-func-template -Wno-unused-template -Wno-vla -Wno-weak-template-vtables -Wno-weak-vtables -Wno-thread-safety-negative -Wno-enum-constexpr-conversion -Wno-unsafe-buffer-usage -O2 -g -DNDEBUG -O3 -g -gdwarf-4 -flto=thin -fwhole-program-vtables -isysroot /home/ubuntu/repo/ch4/cmake/darwin/..
/toolchain/darwin-x86_64 -mmacosx-version-min=10.15 -Wl,-headerpad_max_install_names --ld-path=/home/ubuntu/cctools/bin/x86_64-apple-darwin-ld -rdynamic -Wl,-U,_inside_main -flto=thin -fwhole-program-vtables utils/self-extracting-executable/CMakeFiles/pre_compressor.dir/compressor.cpp.o -o utils/self-extracting-executable/pre_compressor contrib/zstd-cmake/lib_zstd.a contrib/libcxx-cmake/libcxx.a contrib/lib
cxxabi-cmake/libcxxabi.a -nodefaultlibs -lc -lm -lpthread -ldl && :
clang: warning: argument unused during compilation: '-stdlib=libc++' [-Wunused-command-line-argument]
ld: warning: ignoring file utils/self-extracting-executable/CMakeFiles/pre_compressor.dir/compressor.cpp.o, building for macOS-x86_64 but attempting to link with file built for unknown-unsupported file format ( 0xDE 0xC0 0x17 0x0B 0x00 0x00 0x00 0x00 0x14 0x00 0x00 0x00 0x88 0x3E 0x03 0x00 )
ld: warning: ignoring file contrib/zstd-cmake/lib_zstd.a, building for macOS-x86_64 but attempting to link with file built for macOS-x86_64
ld: warning: ignoring file contrib/libcxxabi-cmake/libcxxabi.a, building for macOS-x86_64 but attempting to link with file built for unknown-unsupported file format ( 0x21 0x3C 0x61 0x72 0x63 0x68 0x3E 0x0A 0x23 0x31 0x2F 0x31 0x32 0x20 0x20 0x20 )
ld: warning: ignoring file contrib/libcxx-cmake/libcxx.a, building for macOS-x86_64 but attempting to link with file built for unknown-unsupported file format ( 0x21 0x3C 0x61 0x72 0x63 0x68 0x3E 0x0A 0x23 0x31 0x2F 0x31 0x32 0x20 0x20 0x20 )
Undefined symbols for architecture x86_64:
"_main", referenced from:
implicit entry/start for main executable
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
ninja: build stopped: subcommand failed.
