Revert "Enable -Wsuggest-override in the LLVM build" and the follow-ups.

After lots of follow-up fixes, there are still problems, such as
-Wno-suggest-override getting passed to the Windows Resource Compiler
because it was added with add_definitions in the CMake file.

Rather than piling on another fix, let's revert so this can be re-landed
when there's a proper fix.

This reverts commit 21c0b4c.
This reverts commit 81d68ad.
This reverts commit a361aa5.
This reverts commit fa42b7c.
This reverts commit 955f87f.
This reverts commit 8b16e45.
This reverts commit 308a127.
This reverts commit 274b6b0.
This reverts commit 1c7037a.

Author: zmodem

clang-tools-extra/clangd/unittests/CMakeLists.txt

@@ -22,10 +22,6 @@ if(CLANG_BUILT_STANDALONE)
   endif()
 endif()
 
-if (CXX_SUPPORTS_SUGGEST_OVERRIDE_FLAG)
-  add_definitions("-Wno-suggest-override")
-endif()
-
 if (CLANGD_ENABLE_REMOTE)
   include_directories(${CMAKE_CURRENT_BINARY_DIR}/../index/remote)
   add_definitions(-DGOOGLE_PROTOBUF_NO_RTTI=1)

clang-tools-extra/unittests/CMakeLists.txt

@@ -5,10 +5,6 @@ function(add_extra_unittest test_dirname)
   add_unittest(ExtraToolsUnitTests ${test_dirname} ${ARGN})
 endfunction()
 
-if (CXX_SUPPORTS_SUGGEST_OVERRIDE_FLAG)
-  add_definitions("-Wno-suggest-override")
-endif()
-
 add_subdirectory(clang-apply-replacements)
 add_subdirectory(clang-change-namespace)
 add_subdirectory(clang-doc)

clang/unittests/CMakeLists.txt

@@ -10,10 +10,6 @@ if(CLANG_BUILT_STANDALONE)
   endif()
 endif()
 
-if (CXX_SUPPORTS_SUGGEST_OVERRIDE_FLAG)
-  add_definitions("-Wno-suggest-override")
-endif()
-
 # add_clang_unittest(test_dirname file1.cpp file2.cpp)
 #
 # Will compile the list of files together and link against the clang

compiler-rt/cmake/Modules/AddCompilerRT.cmake

@@ -403,7 +403,6 @@ set(COMPILER_RT_GMOCK_CFLAGS
 
 append_list_if(COMPILER_RT_DEBUG -DSANITIZER_DEBUG=1 COMPILER_RT_UNITTEST_CFLAGS)
 append_list_if(COMPILER_RT_HAS_WCOVERED_SWITCH_DEFAULT_FLAG -Wno-covered-switch-default COMPILER_RT_UNITTEST_CFLAGS)
-append_list_if(COMPILER_RT_HAS_WSUGGEST_OVERRIDE_FLAG -Wno-suggest-override COMPILER_RT_UNITTEST_CFLAGS)
 
 if(MSVC)
   # gtest use a lot of stuff marked as deprecated on Windows.

compiler-rt/cmake/config-ix.cmake

@@ -106,7 +106,6 @@ check_cxx_compiler_flag("-Werror -Wnon-virtual-dtor"   COMPILER_RT_HAS_WNON_VIRT
 check_cxx_compiler_flag("-Werror -Wvariadic-macros"    COMPILER_RT_HAS_WVARIADIC_MACROS_FLAG)
 check_cxx_compiler_flag("-Werror -Wunused-parameter"   COMPILER_RT_HAS_WUNUSED_PARAMETER_FLAG)
 check_cxx_compiler_flag("-Werror -Wcovered-switch-default" COMPILER_RT_HAS_WCOVERED_SWITCH_DEFAULT_FLAG)
-check_cxx_compiler_flag("-Werror -Wsuggest-override"   COMPILER_RT_HAS_WSUGGEST_OVERRIDE_FLAG)
 check_cxx_compiler_flag(-Wno-pedantic COMPILER_RT_HAS_WNO_PEDANTIC)
 
 check_cxx_compiler_flag(/W4 COMPILER_RT_HAS_W4_FLAG)

flang/unittests/CMakeLists.txt

@@ -5,10 +5,6 @@ function(add_flang_unittest test_dirname)
   add_unittest(FlangUnitTests ${test_dirname} ${ARGN})
 endfunction()
 
-if (CXX_SUPPORTS_SUGGEST_OVERRIDE_FLAG)
-  add_definitions("-Wno-suggest-override")
-endif()
-
 add_subdirectory(Optimizer)
 add_subdirectory(Decimal)
 add_subdirectory(Evaluate)

libcxx/CMakeLists.txt

@@ -578,7 +578,6 @@ function(cxx_add_warning_flags target)
     target_add_compile_flags_if_supported(${target} PRIVATE
       -Wno-user-defined-literals
       -Wno-covered-switch-default
-      -Wno-suggest-override
       -Wno-ignored-attributes # FIXME: Caused by _LIBCPP_NODEBUG_TYPE not being supported on older clangs
     )
     if (LIBCXX_TARGETING_CLANG_CL)
@@ -603,8 +602,7 @@ function(cxx_add_warning_flags target)
     target_add_compile_flags_if_supported(${target} PRIVATE
       -Wno-literal-suffix
       -Wno-c++14-compat
-      -Wno-noexcept-type
-      -Wno-suggest-override)
+      -Wno-noexcept-type)
   endif()
   if (LIBCXX_ENABLE_WERROR)
     target_add_compile_flags_if_supported(${target} PRIVATE -Werror)

libcxxabi/CMakeLists.txt

@@ -283,8 +283,6 @@ add_compile_flags_if_supported(-Wunused-variable)
 add_compile_flags_if_supported(-Wwrite-strings)
 add_compile_flags_if_supported(-Wundef)
 
-add_compile_flags_if_supported(-Wno-suggest-override)
-
 if (LIBCXXABI_ENABLE_WERROR)
   add_compile_flags_if_supported(-Werror)
   add_compile_flags_if_supported(-WX)

lld/unittests/CMakeLists.txt

@@ -12,9 +12,5 @@ function(add_lld_unittest test_dirname)
   target_link_libraries(${test_dirname} ${LLVM_COMMON_LIBS})
 endfunction()
 
-if (CXX_SUPPORTS_SUGGEST_OVERRIDE_FLAG)
-  add_definitions("-Wno-suggest-override")
-endif()
-
 add_subdirectory(DriverTests)
 add_subdirectory(MachOTests)

lldb/unittests/CMakeLists.txt

@@ -5,10 +5,6 @@ add_dependencies(lldb-test-deps LLDBUnitTests)
 include_directories(${LLDB_SOURCE_ROOT})
 include_directories(${LLDB_PROJECT_ROOT}/unittests)
 
-if (CXX_SUPPORTS_SUGGEST_OVERRIDE_FLAG)
-  add_definitions("-Wno-suggest-override")
-endif()
-
 set(LLDB_GTEST_COMMON_INCLUDE ${CMAKE_CURRENT_SOURCE_DIR}/gtest_common.h)
 if (MSVC)
   list(APPEND LLVM_COMPILE_FLAGS /FI ${LLDB_GTEST_COMMON_INCLUDE})

llvm/cmake/modules/HandleLLVMOptions.cmake

@@ -672,21 +672,6 @@ if (LLVM_ENABLE_WARNINGS AND (LLVM_COMPILER_IS_GCC_COMPATIBLE OR CLANG_CL))
   # Enable -Wdelete-non-virtual-dtor if available.
   add_flag_if_supported("-Wdelete-non-virtual-dtor" DELETE_NON_VIRTUAL_DTOR_FLAG)
 
-  # Enable -Wsuggest-override if it's available, and only if it doesn't
-  # suggest adding 'override' to functions that are already marked 'final'
-  # (which means it is disabled for GCC < 9.2).
-  check_cxx_compiler_flag("-Wsuggest-override" CXX_SUPPORTS_SUGGEST_OVERRIDE_FLAG)
-  if (CXX_SUPPORTS_SUGGEST_OVERRIDE_FLAG)
-    set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
-    set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -Werror=suggest-override")
-    CHECK_CXX_SOURCE_COMPILES("class base {public: virtual void anchor();};
-                               class derived : base {public: void anchor() final;};
-                               int main() { return 0; }"
-                              CXX_WSUGGEST_OVERRIDE_ALLOWS_ONLY_FINAL)
-    set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
-    append_if(CXX_WSUGGEST_OVERRIDE_ALLOWS_ONLY_FINAL "-Wsuggest-override" CMAKE_CXX_FLAGS)
-  endif()
-
   # Check if -Wcomment is OK with an // comment ending with '\' if the next
   # line is also a // comment.
   set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})

llvm/lib/Testing/Support/CMakeLists.txt

@@ -15,10 +15,6 @@ add_llvm_library(LLVMTestingSupport
   Support
   )
 
-if (CXX_SUPPORTS_SUGGEST_OVERRIDE_FLAG)
-  add_definitions("-Wno-suggest-override")
-endif()
-
 include_directories(${LLVM_MAIN_SRC_DIR}/utils/unittest/googletest/include)
 include_directories(${LLVM_MAIN_SRC_DIR}/utils/unittest/googlemock/include)
 target_link_libraries(LLVMTestingSupport PRIVATE gtest)

llvm/unittests/CMakeLists.txt

@@ -14,10 +14,6 @@ function(add_llvm_target_unittest test_dir_name)
   add_llvm_unittest(${test_dir_name} DISABLE_LLVM_LINK_LLVM_DYLIB ${ARGN})
 endfunction()
 
-if (CXX_SUPPORTS_SUGGEST_OVERRIDE_FLAG)
-  add_definitions("-Wno-suggest-override")
-endif()
-
 add_subdirectory(ADT)
 add_subdirectory(Analysis)
 add_subdirectory(AsmParser)

llvm/utils/benchmark/CMakeLists.txt

@@ -156,10 +156,6 @@ else()
     add_cxx_compiler_flag(-fno-exceptions)
   endif()
 
-  if (CXX_SUPPORTS_SUGGEST_OVERRIDE_FLAG)
-    add_cxx_compiler_flag(-Wno-suggest-override)
-  endif()
-
   if (HAVE_CXX_FLAG_FSTRICT_ALIASING)
     if (NOT CMAKE_CXX_COMPILER_ID STREQUAL "Intel") #ICC17u2: Many false positives for Wstrict-aliasing
       add_cxx_compiler_flag(-Wstrict-aliasing)

llvm/utils/unittest/CMakeLists.txt

@@ -43,9 +43,6 @@ endif()
 if(CXX_SUPPORTS_COVERED_SWITCH_DEFAULT_FLAG)
   add_definitions("-Wno-covered-switch-default")
 endif()
-if(CXX_SUPPORTS_SUGGEST_OVERRIDE_FLAG)
-  add_definitions("-Wno-suggest-override")
-endif()
 
 set(LLVM_REQUIRES_RTTI 1)
 add_definitions( -DGTEST_HAS_RTTI=0 )

mlir/unittests/CMakeLists.txt

@@ -5,10 +5,6 @@ function(add_mlir_unittest test_dirname)
   add_unittest(MLIRUnitTests ${test_dirname} ${ARGN})
 endfunction()
 
-if (CXX_SUPPORTS_SUGGEST_OVERRIDE_FLAG)
-  add_definitions("-Wno-suggest-override")
-endif()
-
 add_subdirectory(Analysis)
 add_subdirectory(Dialect)
 add_subdirectory(IR)

parallel-libs/acxxel/CMakeLists.txt

@@ -36,9 +36,6 @@ set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 # Add warning flags.
 set(CMAKE_CXX_FLAGS  "${CMAKE_CXX_FLAGS} -Wall -Wextra")
-if (CXX_SUPPORTS_SUGGEST_OVERRIDE_FLAG)
-  add_definitions("-Wno-suggest-override")
-endif()
 
 add_library(
     acxxel

polly/unittests/CMakeLists.txt

@@ -19,10 +19,6 @@ function(add_polly_unittest test_name)
   target_link_libraries(${test_name} PRIVATE Polly)
 endfunction()
 
-if (CXX_SUPPORTS_SUGGEST_OVERRIDE_FLAG)
-  add_definitions("-Wno-suggest-override")
-endif()
-
 add_subdirectory(Isl)
 add_subdirectory(Flatten)
 add_subdirectory(DeLICM)