[libunwind] 6b7a49b - Fix all the CMake code that can only handle -stdlib= but not --stdlib=

[Raphael Isemann via cfe-commits]

Author: Raphael Isemann
Date: 2020-10-13T16:05:21+02:00
New Revision: 6b7a49bb43d58c2c08fddb9f6c538ee52806de0a

URL: https://github.com/llvm/llvm-project/commit/6b7a49bb43d58c2c08fddb9f6c538ee52806de0a
DIFF: https://github.com/llvm/llvm-project/commit/6b7a49bb43d58c2c08fddb9f6c538ee52806de0a.diff

LOG: Fix all the CMake code that can only handle -stdlib= but not --stdlib=

There are several places in LLVM's CMake setup that try to remove the
`stdlib=...` flag from the CMake flags. All this code however only considered
the `-stdlib=` variant of the flag but not the alternative spelling with a
double dash. This causes that when one adds `--stdlib=...` to the user-provided
CMake flags that this gets transformed into just `-` which ends up causing the
build system to think it should read the source from stdin (which then lead to
very confusing build errors).

This just adds the alternative spelling before the`-stdlib=` variant in all
these places

Reviewed By: ldionne

Differential Revision: https://reviews.llvm.org/D87133

Added: 
    

Modified: 
    libcxx/CMakeLists.txt
    libcxxabi/CMakeLists.txt
    libunwind/CMakeLists.txt

Removed: 
    


################################################################################
diff  --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt
index 287059548e42..ee250374732d 100644
--- a/libcxx/CMakeLists.txt
+++ b/libcxx/CMakeLists.txt
@@ -478,7 +478,7 @@ if (NOT LIBCXX_STANDALONE_BUILD)
   remove_flags(-DNDEBUG -UNDEBUG -D_DEBUG
                -lc++abi)
 endif()
-remove_flags(-stdlib=libc++ -stdlib=libstdc++)
+remove_flags(--stdlib=libc++ -stdlib=libc++ --stdlib=libstdc++ -stdlib=libstdc++)
 
 # FIXME: Remove all debug flags and flags that change which Windows
 # default libraries are linked. Currently we only support linking the

diff  --git a/libcxxabi/CMakeLists.txt b/libcxxabi/CMakeLists.txt
index 10ac112c90d9..c4d76ea22eca 100644
--- a/libcxxabi/CMakeLists.txt
+++ b/libcxxabi/CMakeLists.txt
@@ -248,6 +248,8 @@ if (LIBCXXABI_HAS_NOSTDINCXX_FLAG)
   # See: https://gitlab.kitware.com/cmake/cmake/issues/19227
   set(CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES "")
   # Remove -stdlib flags to prevent them from causing an unused flag warning.
+  string(REPLACE "--stdlib=libc++" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+  string(REPLACE "--stdlib=libstdc++" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
   string(REPLACE "-stdlib=libc++" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
   string(REPLACE "-stdlib=libstdc++" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
 endif()

diff  --git a/libunwind/CMakeLists.txt b/libunwind/CMakeLists.txt
index 7851f3e45d0c..ebe9e449ec02 100644
--- a/libunwind/CMakeLists.txt
+++ b/libunwind/CMakeLists.txt
@@ -321,6 +321,8 @@ add_cxx_compile_flags_if_supported(-fno-rtti)
 if (LIBUNWIND_HAS_NOSTDINCXX_FLAG)
   list(APPEND LIBUNWIND_COMPILE_FLAGS -nostdinc++)
   # Remove -stdlib flags to prevent them from causing an unused flag warning.
+  string(REPLACE "--stdlib=libc++" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+  string(REPLACE "--stdlib=libstdc++" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
   string(REPLACE "-stdlib=libc++" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
   string(REPLACE "-stdlib=libstdc++" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
 endif()