[PATCH] Always add -lc++abi when using vptr sanitizer on Darwin.

[Kuba Brecka]

I can reproduce on the testcase from https://code.google.com/p/address-sanitizer/issues/detail?id=367:

  $ ./bin/clang++ a.cpp
  $ ./bin/clang++ a.cpp -fsanitize=undefined
  Undefined symbols for architecture x86_64:
    "typeinfo for __cxxabiv1::__class_type_info", referenced from:
        __ubsan::checkDynamicType(void*, void*, unsigned long) in libclang_rt.ubsan_osx.a(ubsan_type_hash.cc.o)
        isDerivedFromAtOffset(__cxxabiv1::__class_type_info const*, __cxxabiv1::__class_type_info const*, long) in libclang_rt.ubsan_osx.a(ubsan_type_hash.cc.o)
        findBaseAtOffset(__cxxabiv1::__class_type_info const*, long) in libclang_rt.ubsan_osx.a(ubsan_type_hash.cc.o)
    "typeinfo for __cxxabiv1::__si_class_type_info", referenced from:
        isDerivedFromAtOffset(__cxxabiv1::__class_type_info const*, __cxxabiv1::__class_type_info const*, long) in libclang_rt.ubsan_osx.a(ubsan_type_hash.cc.o)
        findBaseAtOffset(__cxxabiv1::__class_type_info const*, long) in libclang_rt.ubsan_osx.a(ubsan_type_hash.cc.o)
    "typeinfo for __cxxabiv1::__vmi_class_type_info", referenced from:
        isDerivedFromAtOffset(__cxxabiv1::__class_type_info const*, __cxxabiv1::__class_type_info const*, long) in libclang_rt.ubsan_osx.a(ubsan_type_hash.cc.o)
        findBaseAtOffset(__cxxabiv1::__class_type_info const*, long) in libclang_rt.ubsan_osx.a(ubsan_type_hash.cc.o)
  ld: symbol(s) not found for architecture x86_64
  clang-3.6: error: linker command failed with exit code 1 (use -v to see invocation)
  $ ./bin/clang++ a.cpp -fsanitize=undefined -lc++abi
  $

The mangled names of these are:

  __ZTIN10__cxxabiv117__class_type_infoE
  __ZTIN10__cxxabiv120__si_class_type_infoE
  __ZTIN10__cxxabiv121__vmi_class_type_infoE

It looks like libc++ is actually re-exporting a lot of symbols from libc++abi, but it doesn't re-export all of them:

  $ dyldinfo -export /usr/lib/libc++.dylib | grep cxxabiv117__class
  [re-export] __ZTSN10__cxxabiv117__class_type_infoE (from libc++abi)
  [re-export] __ZTVN10__cxxabiv117__class_type_infoE (from libc++abi)
  [re-export] __ZTSN10__cxxabiv117__class_type_infoE (from libc++abi)
  [re-export] __ZTVN10__cxxabiv117__class_type_infoE (from libc++abi)
  $ dyldinfo -export /usr/lib/libc++.dylib | grep __ZTIN10__cxxabiv117__class_type_infoE
  $ 

So it looks like a libc++ issue (assuming the missing symbols are meant to be re-exported), and they need to be added to libcxx/lib/libc++abi.exp.


http://reviews.llvm.org/D6960

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