[all-commits] [llvm/llvm-project] 938c70: Revert "Enable `-funwind-tables` flag when buildin...

[Martin Storsjö via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 938c70b86c7d2165f8c28d5700e9c1ac1263307e
      https://github.com/llvm/llvm-project/commit/938c70b86c7d2165f8c28d5700e9c1ac1263307e
  Author: Martin Storsjö <martin at martin.st>
  Date:   2019-12-04 (Wed, 04 Dec 2019)

  Changed paths:
    M libunwind/CMakeLists.txt
    M libunwind/cmake/config-ix.cmake
    M libunwind/test/CMakeLists.txt
    M libunwind/test/libunwind/test/config.py
    M libunwind/test/lit.site.cfg.in
    M libunwind/test/signal_frame.pass.cpp

  Log Message:
  -----------
  Revert "Enable `-funwind-tables` flag when building libunwind"

This reverts commit b3fdf33ba6aa7ef80621696f74aaf2f6f8e1d1de.

This change broke building libunwind for Windows/MinGW, and broke
on aspect of the CMake tests in libunwind in general.

After set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY), CMake
skips the linking step in tests, but cmake/config-ix.cmake also
does a few checks for functions in libraries (looking for whether
-lc provides fopen and whether -ldl provides dladdr).

As CMake only tests building a static library, these tests
incorrectly succeed and CMake concludes "Looking for fopen in c -
found" and "Looking for dladdr in dl - found", while building
then fails at the end with errors about unable to find -lc and -ldl.