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[CMake] Set correct flags for clang-cl (#278)

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clang-cl produce binaries with MSVC ABI and wants to be as flag-compatible with pure MSVC as possible, so this leads to all sorts of weird cases.

clang-cl alias /Wall as clang's -Weverything which is way too verbose, so it needs /W3 like pure MSVC.
clang-cl only understand GCC style warning flags (-W[no]blah) and just silent drop MSVC style warning flags (/wd[num]).
clang-cl needs MSVC define flags since it is consuming the same header files as pure MSVC.
CMake set CMAKE_CXX_COMPILER_ID as Clang when clang-cl is detected, so need extra if (MSVC) to differentiate it.

We are not doing clang-cl specialization in Bazel as currently there is no reliable way to detect clang-cl in Bazel..

This PR should be NFC for LLVM/GCC users on Unix platforms.

Other changes:

Add ABSL_ prefix to variable names to avoid name collision in CMake.
This commit is contained in:
Loo Rong Jie 2019-03-23 03:23:01 +08:00 • committed by Derek Mauro
parent e75672f6af
commit 253eb74164
6 changed files with 346 additions and 169 deletions
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39
absl/copts/AbseilConfigureCopts.cmake
View file

@ -5,26 +5,33 @@ set(ABSL_LSAN_LINKOPTS "")
set(ABSL_HAVE_LSAN OFF)
if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
set(ABSL_DEFAULT_COPTS "${GCC_FLAGS}")
set(ABSL_TEST_COPTS "${GCC_FLAGS};${GCC_TEST_FLAGS}")
set(ABSL_EXCEPTIONS_FLAG "${GCC_EXCEPTIONS_FLAGS}")
set(ABSL_DEFAULT_COPTS "${ABSL_GCC_FLAGS}")
set(ABSL_TEST_COPTS "${ABSL_GCC_FLAGS};${ABSL_GCC_TEST_FLAGS}")
set(ABSL_EXCEPTIONS_FLAG "${ABSL_GCC_EXCEPTIONS_FLAGS}")
elseif("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
# MATCHES so we get both Clang and AppleClang
set(ABSL_DEFAULT_COPTS "${LLVM_FLAGS}")
set(ABSL_TEST_COPTS "${LLVM_FLAGS};${LLVM_TEST_FLAGS}")
set(ABSL_EXCEPTIONS_FLAG "${LLVM_EXCEPTIONS_FLAGS}")
if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
# AppleClang doesn't have lsan
# https://developer.apple.com/documentation/code_diagnostics
if(CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 3.5)
set(ABSL_LSAN_LINKOPTS "-fsanitize=leak")
set(ABSL_HAVE_LSAN ON)
if (MSVC)
# clang-cl is half MSVC, half LLVM
set(ABSL_DEFAULT_COPTS "${ABSL_CLANG_CL_FLAGS}")
set(ABSL_TEST_COPTS "${ABSL_CLANG_CL_FLAGS};${ABSL_CLANG_CL_TEST_FLAGS}")
set(ABSL_EXCEPTIONS_FLAG "${ABSL_CLANG_CL_EXCEPTIONS_FLAGS}")
else()
set(ABSL_DEFAULT_COPTS "${ABSL_LLVM_FLAGS}")
set(ABSL_TEST_COPTS "${ABSL_LLVM_FLAGS};${ABSL_LLVM_TEST_FLAGS}")
set(ABSL_EXCEPTIONS_FLAG "${ABSL_LLVM_EXCEPTIONS_FLAGS}")
if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
# AppleClang doesn't have lsan
# https://developer.apple.com/documentation/code_diagnostics
if(CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 3.5)
set(ABSL_LSAN_LINKOPTS "-fsanitize=leak")
set(ABSL_HAVE_LSAN ON)
endif()
endif()
endif()
elseif("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
set(ABSL_DEFAULT_COPTS "${MSVC_FLAGS}")
set(ABSL_TEST_COPTS "${MSVC_FLAGS};${MSVC_TEST_FLAGS}")
set(ABSL_EXCEPTIONS_FLAG "${MSVC_EXCEPTIONS_FLAGS}")
set(ABSL_DEFAULT_COPTS "${ABSL_MSVC_FLAGS}")
set(ABSL_TEST_COPTS "${ABSL_MSVC_FLAGS};${ABSL_MSVC_TEST_FLAGS}")
set(ABSL_EXCEPTIONS_FLAG "${ABSL_MSVC_EXCEPTIONS_FLAGS}")
else()
message(WARNING "Unknown compiler: ${CMAKE_CXX_COMPILER}. Building with no default flags")
set(ABSL_DEFAULT_COPTS "")
@ -42,4 +49,4 @@ elseif(NOT "${CMAKE_CXX_STANDARD}")
set(ABSL_CXX_STANDARD 11)
else()
set(ABSL_CXX_STANDARD "${CMAKE_CXX_STANDARD}")
endif()
endif()