[CIR] Disable gcc partially overloaded virtual warning (#130322)

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.

Author: andykaylor

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)

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
 )