[CMake][WinMsvc] Fix user passed compiler/linker flags

Users could pass flags by environment variables like CFLAGS/CXXFLAGS/LDFLAGS
or by using CMAKE_<LANG>_FLAGS_INIT/CMAKE_<t>_LINKER_FLAGS_INIT. So this
toolchain file should append to INIT flags instead. Otherwise, user
flags would be discarded here by assigning to CMAKE_<LANG>_FLAGS
directly.

Reviewed By: smeenai, mstorsjo

Differential Revision: https://reviews.llvm.org/D116709
This commit is contained in:
Yuanfang Chen 2022-01-07 16:34:38 -08:00
parent 69c8e64ba6
commit d6d3000a2f
1 changed files with 8 additions and 22 deletions

View File

@ -84,6 +84,7 @@
# up a VFS overlay for the SDK headers and case-correcting symlinks for the
# libraries when running on a case-sensitive filesystem.
include_guard(GLOBAL)
# When configuring CMake with a toolchain file against a top-level CMakeLists.txt,
# it will actually run CMake many times, once for each small test program used to
@ -251,6 +252,8 @@ list(APPEND _CTF_NATIVE_DEFAULT "-DCMAKE_ASM_COMPILER=${LLVM_NATIVE_TOOLCHAIN}/b
list(APPEND _CTF_NATIVE_DEFAULT "-DCMAKE_C_COMPILER=${LLVM_NATIVE_TOOLCHAIN}/bin/clang")
list(APPEND _CTF_NATIVE_DEFAULT "-DCMAKE_CXX_COMPILER=${LLVM_NATIVE_TOOLCHAIN}/bin/clang++")
# These flags are used during build time. So if CFLAGS/CXXFLAGS/LDFLAGS is set
# for the target, makes sure these are unset during build time.
set(CROSS_TOOLCHAIN_FLAGS_NATIVE "${_CTF_NATIVE_DEFAULT}" CACHE STRING "")
set(COMPILE_FLAGS
@ -277,18 +280,8 @@ if(case_sensitive_filesystem)
endif()
string(REPLACE ";" " " COMPILE_FLAGS "${COMPILE_FLAGS}")
# We need to preserve any flags that were passed in by the user. However, we
# can't append to CMAKE_C_FLAGS and friends directly, because toolchain files
# will be re-invoked on each reconfigure and therefore need to be idempotent.
# The assignments to the _INITIAL cache variables don't use FORCE, so they'll
# only be populated on the initial configure, and their values won't change
# afterward.
set(_CMAKE_C_FLAGS_INITIAL "${CMAKE_C_FLAGS}" CACHE STRING "")
set(CMAKE_C_FLAGS "${_CMAKE_C_FLAGS_INITIAL} ${COMPILE_FLAGS}" CACHE STRING "" FORCE)
set(_CMAKE_CXX_FLAGS_INITIAL "${CMAKE_CXX_FLAGS}" CACHE STRING "")
set(CMAKE_CXX_FLAGS "${_CMAKE_CXX_FLAGS_INITIAL} ${COMPILE_FLAGS}" CACHE STRING "" FORCE)
string(APPEND CMAKE_C_FLAGS_INIT " ${COMPILE_FLAGS}")
string(APPEND CMAKE_CXX_FLAGS_INIT " ${COMPILE_FLAGS}")
set(LINK_FLAGS
# Prevent CMake from attempting to invoke mt.exe. It only recognizes the slashed form and not the dashed form.
@ -312,16 +305,9 @@ if(case_sensitive_filesystem)
endif()
string(REPLACE ";" " " LINK_FLAGS "${LINK_FLAGS}")
# See explanation for compiler flags above for the _INITIAL variables.
set(_CMAKE_EXE_LINKER_FLAGS_INITIAL "${CMAKE_EXE_LINKER_FLAGS}" CACHE STRING "")
set(CMAKE_EXE_LINKER_FLAGS "${_CMAKE_EXE_LINKER_FLAGS_INITIAL} ${LINK_FLAGS}" CACHE STRING "" FORCE)
set(_CMAKE_MODULE_LINKER_FLAGS_INITIAL "${CMAKE_MODULE_LINKER_FLAGS}" CACHE STRING "")
set(CMAKE_MODULE_LINKER_FLAGS "${_CMAKE_MODULE_LINKER_FLAGS_INITIAL} ${LINK_FLAGS}" CACHE STRING "" FORCE)
set(_CMAKE_SHARED_LINKER_FLAGS_INITIAL "${CMAKE_SHARED_LINKER_FLAGS}" CACHE STRING "")
set(CMAKE_SHARED_LINKER_FLAGS "${_CMAKE_SHARED_LINKER_FLAGS_INITIAL} ${LINK_FLAGS}" CACHE STRING "" FORCE)
string(APPEND CMAKE_EXE_LINKER_FLAGS_INIT " ${LINK_FLAGS}")
string(APPEND CMAKE_MODULE_LINKER_FLAGS_INIT " ${LINK_FLAGS}")
string(APPEND CMAKE_SHARED_LINKER_FLAGS_INIT " ${LINK_FLAGS}")
# CMake populates these with a bunch of unnecessary libraries, which requires
# extra case-correcting symlinks and what not. Instead, let projects explicitly