From e546bbfda0ab91cf78c096d8c035851cc7c3b9f3 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Martin=20Storsj=C3=B6?= Date: Wed, 6 Apr 2022 13:45:20 +0300 Subject: [PATCH] [lldb] Fix detecting warning options for GCC MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit If testing for a warning option like -Wno- with GCC, GCC won't print any diagnostic at all, leading to the options being accepted incorrectly. However later, if compiling a file that actually prints another warning, GCC will also print warnings about these -Wno- options being unrecognized. This avoids warning spam like this, for every lldb source file that produces build warnings with GCC: At global scope: cc1plus: warning: unrecognized command line option ‘-Wno-vla-extension’ cc1plus: warning: unrecognized command line option ‘-Wno-deprecated-register’ This matches how such warning options are detected and added in llvm/cmake/modules/HandleLLVMOptions.cmake, e.g. like this: check_cxx_compiler_flag("-Wclass-memaccess" CXX_SUPPORTS_CLASS_MEMACCESS_FLAG) append_if(CXX_SUPPORTS_CLASS_MEMACCESS_FLAG "-Wno-class-memaccess" CMAKE_CXX_FLAGS) Differential Revision: https://reviews.llvm.org/D123202 --- lldb/cmake/modules/LLDBConfig.cmake | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) diff --git a/lldb/cmake/modules/LLDBConfig.cmake b/lldb/cmake/modules/LLDBConfig.cmake index 69aaadf..25d1cc5 100644 --- a/lldb/cmake/modules/LLDBConfig.cmake +++ b/lldb/cmake/modules/LLDBConfig.cmake @@ -168,22 +168,27 @@ else () endif () include_directories("${CMAKE_CURRENT_BINARY_DIR}/../clang/include") +# GCC silently accepts any -Wno- option, but warns about those options +# being unrecognized only if the compilation triggers other warnings to be +# printed. Therefore, check for whether the compiler supports options in the +# form -W, and if supported, add the corresponding -Wno- option. + # Disable GCC warnings -check_cxx_compiler_flag("-Wno-deprecated-declarations" CXX_SUPPORTS_NO_DEPRECATED_DECLARATIONS) -append_if(CXX_SUPPORTS_NO_DEPRECATED_DECLARATIONS "-Wno-deprecated-declarations" CMAKE_CXX_FLAGS) +check_cxx_compiler_flag("-Wdeprecated-declarations" CXX_SUPPORTS_DEPRECATED_DECLARATIONS) +append_if(CXX_SUPPORTS_DEPRECATED_DECLARATIONS "-Wno-deprecated-declarations" CMAKE_CXX_FLAGS) -check_cxx_compiler_flag("-Wno-unknown-pragmas" CXX_SUPPORTS_NO_UNKNOWN_PRAGMAS) -append_if(CXX_SUPPORTS_NO_UNKNOWN_PRAGMAS "-Wno-unknown-pragmas" CMAKE_CXX_FLAGS) +check_cxx_compiler_flag("-Wunknown-pragmas" CXX_SUPPORTS_UNKNOWN_PRAGMAS) +append_if(CXX_SUPPORTS_UNKNOWN_PRAGMAS "-Wno-unknown-pragmas" CMAKE_CXX_FLAGS) -check_cxx_compiler_flag("-Wno-strict-aliasing" CXX_SUPPORTS_NO_STRICT_ALIASING) -append_if(CXX_SUPPORTS_NO_STRICT_ALIASING "-Wno-strict-aliasing" CMAKE_CXX_FLAGS) +check_cxx_compiler_flag("-Wstrict-aliasing" CXX_SUPPORTS_STRICT_ALIASING) +append_if(CXX_SUPPORTS_STRICT_ALIASING "-Wno-strict-aliasing" CMAKE_CXX_FLAGS) # Disable Clang warnings -check_cxx_compiler_flag("-Wno-deprecated-register" CXX_SUPPORTS_NO_DEPRECATED_REGISTER) -append_if(CXX_SUPPORTS_NO_DEPRECATED_REGISTER "-Wno-deprecated-register" CMAKE_CXX_FLAGS) +check_cxx_compiler_flag("-Wdeprecated-register" CXX_SUPPORTS_DEPRECATED_REGISTER) +append_if(CXX_SUPPORTS_DEPRECATED_REGISTER "-Wno-deprecated-register" CMAKE_CXX_FLAGS) -check_cxx_compiler_flag("-Wno-vla-extension" CXX_SUPPORTS_NO_VLA_EXTENSION) -append_if(CXX_SUPPORTS_NO_VLA_EXTENSION "-Wno-vla-extension" CMAKE_CXX_FLAGS) +check_cxx_compiler_flag("-Wvla-extension" CXX_SUPPORTS_VLA_EXTENSION) +append_if(CXX_SUPPORTS_VLA_EXTENSION "-Wno-vla-extension" CMAKE_CXX_FLAGS) # Disable MSVC warnings if( MSVC ) -- 2.7.4