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<p class="MsoNormal"><span style="font-size:14.0pt">This is on the master branch of LLVM (11.0.0). I am using clang-7.1.0 to make the build on a CentOS6.6 machine. The complete cmake command line is also below. Any hints on how to resolve this build failure?
Note that I am using: </span><span style="font-size:9.0pt;font-family:"Courier New"">-DLIBCXXABI_USE_COMPILER_RT=ON -DLIBCXXABI_USE_LLVM_UNWINDER=ON
</span><span style="font-size:14.0pt">as I am creating a self-contained clang toolchain that does not depend on libgcc. The 64-bit version builds fine (only 32-bit fails).
</span><span style="font-size:9.0pt;font-family:"Courier New""><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt">The problem seems to be that in 32-bit builds, clang now generates a call to __udivdi3 in cxa_demangle.cpp.o but when linking libc++abi.so results in an the undefined symbol. I am not sure if getting libc++abi.so
to be linked with libclang_rt.builtins (which contains the definition of __udivdi3) is the correct fix. I haven’t looked at why
</span><span style="font-size:9.0pt;font-family:"Courier New"">-DLIBCXXABI_USE_COMPILER_RT=ON</span><span style="font-size:14.0pt"> doesn’t result in libc++abi.so to be linked with compiler-rt builtins. Can anyone familiar with this stuff comment on this?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">projects/libcxxabi/src/CMakeFiles/cxxabi_shared.dir/cxa_demangle.cpp.o: In function `(anonymous namespace)::itanium_demangle::SyntheticTemplateParamName::printLeft((anonymous namespace)::itanium_demangle::OutputStream&)
const': cxa_demangle.cpp:(.text._ZNK12_GLOBAL__N_116itanium_demangle26SyntheticTemplateParamName9printLeftERNS0_12OutputStreamE+0x12a): undefined reference to `__udivdi3'<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">cmake -G Ninja -DLLVM_PATH=/u/riyaz/src/llvm-project/llvm \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DLLVM_ENABLE_PROJECTS=clang;clang-tools-extra;compiler-rt;libcxx;libcxxabi;libunwind;mlir;openmp \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DLLVM_TARGETS_TO_BUILD=X86 \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DLLVM_BUILD_32_BITS=ON \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DLLVM_ENABLE_ZLIB=OFF \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DLLVM_ENABLE_LIBCXX=ON \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DLIBCXXABI_USE_COMPILER_RT=ON \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DLIBCXXABI_USE_LLVM_UNWINDER=ON \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DLIBCXXABI_ENABLE_SHARED=ON \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DLIBCXX_USE_COMPILER_RT=ON \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DLIBCXX_ENABLE_SHARED=ON \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DLIBCXX_ENABLE_ABI_LINKER_SCRIPT=ON \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DLIBCXX_ENABLE_STATIC_ABI_LIBRARY=OFF \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DCOMPILER_RT_USE_BUILTINS_LIBRARY=ON \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DSANITIZER_USE_COMPILER_RT=ON \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DSANITIZER_CXX_ABI=libc++ \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DLIBOMP_USE_COMPILER_RT=ON \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DCMAKE_INSTALL_PREFIX=/u/tools/llvm-11.0.0/linux \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DCMAKE_BUILD_TYPE=Release \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DCMAKE_EXE_LINKER_FLAGS="-rtlib=compiler-rt" \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DCMAKE_SHARED_LINKER_FLAGS="-rtlib=compiler-rt" \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DCMAKE_MODULE_LINKER_FLAGS="-rtlib=compiler-rt" \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DCMAKE_CXX_COMPILER=/u/tools/llvm-7.1.0/linux64/bin/clang++ \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DCMAKE_C_COMPILER=/u/tools/llvm-7.1.0/linux64/bin/clang \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DLIBOMP_COPY_EXPORTS=FALSE \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">-DLIBOMP_CFLAGS=-stdlib=libc++ \<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Courier New"">/u/riyaz/src/llvm-project/llvm<o:p></o:p></span></p>
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