[llvm] Add -Wms-bitfield-padding warning when possible (PR #139828)

[Oliver Hunt via llvm-commits]

https://github.com/ojhunt created https://github.com/llvm/llvm-project/pull/139828

None

>From 9c28f07d03e07fd7d65f35bb6411fabd0df64d6f Mon Sep 17 00:00:00 2001
From: Oliver Hunt <oliver at apple.com>
Date: Tue, 13 May 2025 19:58:08 -0700
Subject: [PATCH] Add -Wms-bitfield-padding warning when possible

---
 llvm/cmake/modules/HandleLLVMOptions.cmake | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/llvm/cmake/modules/HandleLLVMOptions.cmake b/llvm/cmake/modules/HandleLLVMOptions.cmake
index c427a65ee030c..fa476c1239279 100644
--- a/llvm/cmake/modules/HandleLLVMOptions.cmake
+++ b/llvm/cmake/modules/HandleLLVMOptions.cmake
@@ -935,6 +935,10 @@ if (LLVM_ENABLE_WARNINGS AND (LLVM_COMPILER_IS_GCC_COMPATIBLE OR CLANG_CL))
 
   # Enable -Wctad-maybe-unsupported to catch unintended use of CTAD.
   add_flag_if_supported("-Wctad-maybe-unsupported" CTAD_MAYBE_UNSPPORTED_FLAG)
+
+  # Enable -Wms-bitfield-padding to catch padding problems when compiling with
+  # msvc
+  add_flag_if_supported("-Wms-bitfield-padding" MS_BITFIELD_PADDING_FLAG)
 endif (LLVM_ENABLE_WARNINGS AND (LLVM_COMPILER_IS_GCC_COMPATIBLE OR CLANG_CL))
 
 if (LLVM_COMPILER_IS_GCC_COMPATIBLE AND NOT LLVM_ENABLE_WARNINGS)