[CIR] Disable gcc partially overloaded virtual warning

[andykaylor]

GCC, unlike clang, issues a warning when one virtual function is overridden in a derived class but one or more other virtual functions with the same name and different signature from a base class are not overridden. This leads to many warnings in the MLIR and ClangIR code when using the OpenConversionPattern<>::matchAndRewrite() function in the ordinary way. The "hiding" behavior is what we want, so we're just disabling the warning here.

[llvmbot]

@llvm/pr-subscribers-clang

@llvm/pr-subscribers-clangir

Author: Andy Kaylor (andykaylor)

Changes

GCC, unlike clang, issues a warning when one virtual function is overridden in a derived class but one or more other virtual functions with the same name and different signature from a base class are not overridden. This leads to many warnings in the MLIR and ClangIR code when using the OpenConversionPattern<>::matchAndRewrite() function in the ordinary way. The "hiding" behavior is what we want, so we're just disabling the warning here.

---

Full diff: https://github.com/llvm/llvm-project/pull/130322.diff

2 Files Affected:

• (modified) clang/lib/CIR/CMakeLists.txt (+11)
• (modified) clang/tools/cir-opt/CMakeLists.txt (+11)

diff --git a/clang/lib/CIR/CMakeLists.txt b/clang/lib/CIR/CMakeLists.txt
index 4a99ecb33dfb2..7bdf3fcc59035 100644
--- a/clang/lib/CIR/CMakeLists.txt
+++ b/clang/lib/CIR/CMakeLists.txt
@@ -1,6 +1,17 @@
 include_directories(${LLVM_MAIN_SRC_DIR}/../mlir/include)
 include_directories(${CMAKE_BINARY_DIR}/tools/mlir/include)
 
+# GCC, unlike clang, issues a warning when one virtual function is overridden
+# in a derived class but one or more other virtual functions with the same
+# name and different signature from a base class are not overridden. This
+# leads to many warnings in the MLIR and ClangIR code when using the
+# OpenConversionPattern<>::matchAndRewrite() function in the ordinary way.
+# The "hiding" behavior is what we want, so we're just disabling the warning
+# here.
+if (LLVM_COMPILER_IS_GCC_COMPATIBLE AND (NOT "${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang"))
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-overloaded-virtual")
+endif()
+
 add_subdirectory(Dialect)
 add_subdirectory(CodeGen)
 add_subdirectory(FrontendAction)
diff --git a/clang/tools/cir-opt/CMakeLists.txt b/clang/tools/cir-opt/CMakeLists.txt
index 75bec5f4e1b0b..ca7ee44f6fd75 100644
--- a/clang/tools/cir-opt/CMakeLists.txt
+++ b/clang/tools/cir-opt/CMakeLists.txt
@@ -4,6 +4,17 @@ get_property(conversion_libs GLOBAL PROPERTY MLIR_CONVERSION_LIBS)
 include_directories(${LLVM_MAIN_SRC_DIR}/../mlir/include)
 include_directories(${CMAKE_BINARY_DIR}/tools/mlir/include)
 
+# GCC, unlike clang, issues a warning when one virtual function is overridden
+# in a derived class but one or more other virtual functions with the same
+# name and different signature from a base class are not overridden. This
+# leads to many warnings in the MLIR and ClangIR code when using the
+# OpenConversionPattern<>::matchAndRewrite() function in the ordinary way.
+# The "hiding" behavior is what we want, so we're just disabling the warning
+# here.
+if (LLVM_COMPILER_IS_GCC_COMPATIBLE AND (NOT "${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang"))
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-overloaded-virtual")
+endif()
+
 add_clang_tool(cir-opt
   cir-opt.cpp
 )

[erichkeane]

Someone better equipped to review cmake should review this, but looks ok to me.

[andykaylor]

Someone better equipped to review cmake should review this, but looks ok to me.

I'm not sure who is well-versed in the dark art of cmake. I made this same change in the incubator, and it's working there, so I'm confident that it works as intended.

[bcardosolopes]

LGTM, same observation as Erich regarding CMAKE stuff tho