[llvm] 16a0d80 - [CMake][llvm] avoid changing global flags (may be used outside of llvm)

[Francis Visoiu Mistrih via llvm-commits]

Author: Jim Radford
Date: 2021-04-20T16:06:25-07:00
New Revision: 16a0d80912ed9840756edf8b85356cea09456eec

URL: https://github.com/llvm/llvm-project/commit/16a0d80912ed9840756edf8b85356cea09456eec
DIFF: https://github.com/llvm/llvm-project/commit/16a0d80912ed9840756edf8b85356cea09456eec.diff

LOG: [CMake][llvm] avoid changing global flags (may be used outside of llvm)

Changing global flags can break builds of projects that include/build
llvm as a sub-project, as the effect is global. Ideally we would
disable this warning at the directory level instead, but the obvious
way (disabling warning D9025) isn't supported. At least we can limit
the effect to only MSVC.

Patch by Jim Radford.

Differential Revision: https://reviews.llvm.org/D100900

Added: 
    

Modified: 
    llvm/cmake/modules/HandleLLVMOptions.cmake

Removed: 
    


################################################################################
diff  --git a/llvm/cmake/modules/HandleLLVMOptions.cmake b/llvm/cmake/modules/HandleLLVMOptions.cmake
index 8b64694757e9f..e7c30e9d00821 100644
--- a/llvm/cmake/modules/HandleLLVMOptions.cmake
+++ b/llvm/cmake/modules/HandleLLVMOptions.cmake
@@ -62,18 +62,19 @@ if( LLVM_ENABLE_ASSERTIONS )
     # NOTE: use `add_compile_options` rather than `add_definitions` since
     # `add_definitions` does not support generator expressions.
     add_compile_options($<$<OR:$<COMPILE_LANGUAGE:C>,$<COMPILE_LANGUAGE:CXX>>:-UNDEBUG>)
-
-    # Also remove /D NDEBUG to avoid MSVC warnings about conflicting defines.
-    foreach (flags_var_to_scrub
-        CMAKE_CXX_FLAGS_RELEASE
-        CMAKE_CXX_FLAGS_RELWITHDEBINFO
-        CMAKE_CXX_FLAGS_MINSIZEREL
-        CMAKE_C_FLAGS_RELEASE
-        CMAKE_C_FLAGS_RELWITHDEBINFO
-        CMAKE_C_FLAGS_MINSIZEREL)
-      string (REGEX REPLACE "(^| )[/-]D *NDEBUG($| )" " "
-        "${flags_var_to_scrub}" "${${flags_var_to_scrub}}")
-    endforeach()
+    if (MSVC)
+      # Also remove /D NDEBUG to avoid MSVC warnings about conflicting defines.
+      foreach (flags_var_to_scrub
+          CMAKE_CXX_FLAGS_RELEASE
+          CMAKE_CXX_FLAGS_RELWITHDEBINFO
+          CMAKE_CXX_FLAGS_MINSIZEREL
+          CMAKE_C_FLAGS_RELEASE
+          CMAKE_C_FLAGS_RELWITHDEBINFO
+          CMAKE_C_FLAGS_MINSIZEREL)
+        string (REGEX REPLACE "(^| )[/-]D *NDEBUG($| )" " "
+          "${flags_var_to_scrub}" "${${flags_var_to_scrub}}")
+      endforeach()
+     endif()
   endif()
 endif()