[PATCH] D100900: [CMake][llvm] avoid changing global flags (may be used outside of llvm)

[Jim Radford via Phabricator via llvm-commits]

radford created this revision.
radford added reviewers: arphaman, rnk.
Herald added a subscriber: mgorny.
radford requested review of this revision.
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.

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 <https://reviews.llvm.org/D9025>) isn't supported.  At least we can limit
the effect to only MSVC.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D100900

Files:
  llvm/cmake/modules/HandleLLVMOptions.cmake


Index: llvm/cmake/modules/HandleLLVMOptions.cmake
===================================================================
--- llvm/cmake/modules/HandleLLVMOptions.cmake
+++ llvm/cmake/modules/HandleLLVMOptions.cmake
@@ -62,18 +62,19 @@
     # 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()
 


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