[llvm] r337492 - Disable GCC's -Wclass-memaccess warning

[Reid Kleckner via llvm-commits]

Author: rnk
Date: Thu Jul 19 13:14:46 2018
New Revision: 337492

URL: http://llvm.org/viewvc/llvm-project?rev=337492&view=rev
Log:
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

Modified:
    llvm/trunk/cmake/modules/HandleLLVMOptions.cmake

Modified: llvm/trunk/cmake/modules/HandleLLVMOptions.cmake
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/cmake/modules/HandleLLVMOptions.cmake?rev=337492&r1=337491&r2=337492&view=diff
==============================================================================
--- llvm/trunk/cmake/modules/HandleLLVMOptions.cmake (original)
+++ llvm/trunk/cmake/modules/HandleLLVMOptions.cmake Thu Jul 19 13:14:46 2018
@@ -579,6 +579,11 @@ if (LLVM_ENABLE_WARNINGS AND (LLVM_COMPI
   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