Disable GCC's -Wclass-memaccess warning
It fires on things like SmallVector<std::pair<int, int>>, where we
intentionally use memcpy instead of calling the assignment operator.
This warning fires in practically every LLVM TU, so we have to do
something about it, even if we aren't interested in being 100% warning
clean with GCC.
Reported as PR37337
llvm-svn: 337492
diff --git a/llvm/cmake/modules/HandleLLVMOptions.cmake b/llvm/cmake/modules/HandleLLVMOptions.cmake
index 3d2dd48..efaad89 100644
--- a/llvm/cmake/modules/HandleLLVMOptions.cmake
+++ b/llvm/cmake/modules/HandleLLVMOptions.cmake
@@ -579,6 +579,11 @@
append_if(USE_NO_UNINITIALIZED "-Wno-uninitialized" CMAKE_CXX_FLAGS)
append_if(USE_NO_MAYBE_UNINITIALIZED "-Wno-maybe-uninitialized" CMAKE_CXX_FLAGS)
+ # Disable -Wclass-memaccess, a C++-only warning from GCC 8 that fires on
+ # LLVM's ADT classes.
+ check_cxx_compiler_flag("-Wclass-memaccess" CXX_SUPPORTS_CLASS_MEMACCESS_FLAG)
+ append_if(CXX_SUPPORTS_CLASS_MEMACCESS_FLAG "-Wno-class-memaccess" CMAKE_CXX_FLAGS)
+
# Check if -Wnon-virtual-dtor warns even though the class is marked final.
# If it does, don't add it. So it won't be added on clang 3.4 and older.
# This also catches cases when -Wnon-virtual-dtor isn't supported by