[libcxx-commits] [PATCH] D111290: [libunwind] Fix test execution.

[Alexander Richardson via Phabricator via libcxx-commits]

arichardson added inline comments.


================
Comment at: libunwind/test/libunwind/test/config.py:70
+        if sanitizers is not None:
+            super().configure_link_flags_cxx_library()
 
----------------
Why do we need the C++ library?

I can see the following issue:
```
$ nm -D -u /usr/lib/gcc/x86_64-linux-gnu/7/libasan.so
                 U _Unwind_Backtrace
                 U _Unwind_GetIP
```

```
readelf --dynamic /usr/lib/gcc/x86_64-linux-gnu/7/libasan.so

Dynamic section at offset 0x151550 contains 31 entries:
  Tag        Type                         Name/Value
 0x0000000000000001 (NEEDED)             Shared library: [libdl.so.2]
 0x0000000000000001 (NEEDED)             Shared library: [librt.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libpthread.so.0]
 0x0000000000000001 (NEEDED)             Shared library: [libm.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [libc.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [libgcc_s.so.1]
 0x000000000000000e (SONAME)             Library soname: [libasan.so.4]
```
And on Ubuntu clang's libclang-rt even links against libstdc++...
```
$ readelf --dynamic /usr/lib/clang/10/lib/linux/libclang_rt.asan-x86_64.so
 0x0000000000000001 (NEEDED)             Shared library: [libstdc++.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [libgcc_s.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libc.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [libdl.so.2]
 0x0000000000000001 (NEEDED)             Shared library: [librt.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libm.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [libpthread.so.0]
 0x000000000000000e (SONAME)             Library soname: [libclang_rt.asan-x86_64.so]
```

Is that the problem?
I don't think we should be linking against the C++ library since that might pull in another unwind library.


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  https://reviews.llvm.org/D111290/new/

https://reviews.llvm.org/D111290