[PATCH] D67298: [ASan] Fix test case dlopen-mixed-c-cxx.c without C++ stdlib

[Jonas Hahnfeld via Phabricator via llvm-commits]

Hahnfeld added a comment.

In D67298#1661672 <https://reviews.llvm.org/D67298#1661672>, @serge-sans-paille wrote:

> Mmmmh the whole point of the test is to test how asan behaves when meeting a symbol like `__cxa_throw` in a dlopened library when the calling compilation unit is not linked against libstdc++. Previous behavior was a segfault, we should now get a reasonable error. By defining `__cxa_throw` in the c file, you remove the origin of the bug, so sure it works, but it no longer tests the faulty situation. Maybe there's a symbol caught by asan and defined in both libcxx and libstdc++?


And that's what I don't understand and what I have been trying to sort out in my comments in D63877 <https://reviews.llvm.org/D63877>: In the default configuration the asan shared library is linked against libstdc++. As the C file is compiled with `-fsanitize=address` it pulls in a definition of `__cxa_throw`, so what's the difference?

For me, it's unacceptable that the test is failing for more than a month on a totally legit configuration. We should get this fixed rather sooner than later, and not being the author I'm grabbing at any straw without really getting insight into what's going on.


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https://reviews.llvm.org/D67298