[cfe-dev] UBSAN: undefined symbols when compiling on macOS Sierra (local config issue?)

[Vedant Kumar via cfe-dev]

You're hitting a bug which is fixed by this patch:

  https://reviews.llvm.org/D24990
  [ubsan] Turn on 'Has CXXABI' to enable support for -fsanitize=vptr on Darwin

As a workaround, try building with:

  -DSANITIZER_CAN_USE_CXXABI:BOOL=ON

vedant

> On Sep 29, 2016, at 10:23 AM, Kevin Ushey via cfe-dev <cfe-dev at lists.llvm.org> wrote:
> 
> Hi everyone,
> 
> I'm running into some issues when attempting to link while using the 'undefined' sanitizer -- when linking my program, I'm getting errors of the form:
> 
> Undefined symbols for architecture x86_64:
>   "___ubsan_handle_dynamic_type_cache_miss", referenced from: <...>
>   "___ubsan_vptr_type_cache", referenced from: <...>
> ld: symbol(s) not found for architecture x86_64
> 
> Looking at the generated ubsan dynamic library, those symbols are not present:
> 
> kevin at cdrv:/usr/local/llvm/db79113/lib/clang/4.0.0/lib/darwin
> $ nm libclang_rt.ubsan_osx_dynamic.dylib | grep "ubsan_vptr_type_cache"
> 
> However, with clang-3.8 provided by Homebrew, these symbols are indeed present:
> 
> kevin at cdrv:/usr/local/Cellar/llvm38/3.8.0/lib/llvm-3.8/lib/clang/3.8.0/lib/darwin
> $ nm libclang_rt.ubsan_osx_dynamic.dylib | grep "ubsan_vptr_type_cache"
> 0000000000b20c00 S ___ubsan_vptr_type_cache
> 
> which I think implies I'm probably missing some bit of configuration when building clang with sanitizers. For reference, I'm building the LLVM tree with:
> 
> cmake -G "Ninja" ..                                  \
>     -DCMAKE_C_COMPILER=/usr/bin/clang                \
>     -DCMAKE_C_FLAGS="${INCLUDE_FLAGS}"               \
>     -DCMAKE_CXX_COMPILER=/usr/bin/clang++            \
>     -DCMAKE_CXX_FLAGS="${INCLUDE_FLAGS}"             \
>     -DCMAKE_SHARED_LINKER_FLAGS="-L/usr/local/lib"   \
>     -DCMAKE_BUILD_TYPE=Release                       \
>     -DCMAKE_INSTALL_PREFIX="${CMAKE_INSTALL_PREFIX}" \
>     -DLLVM_ENABLE_EH=Yes                             \
>     -DLLVM_ENABLE_RTTI=Yes
> cmake --build .
> cmake --build . --target install
> 
> This is built with 'clang' and 'lldb' checked out in the 'llvm/tools' folder, and 'compiler-rt', 'openmp', 'libcxx' and 'libcxxabi' checked out in the 'llvm/projects' folder, and the master branch from the various git mirrors for each project.
> 
> A bit of googling brought me to http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20150622/283017.html, but I'm not sure if it's relevant to this particular issue.
> 
> Any idea what I could be missing?
> 
> Thanks,
> Kevin
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