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[flang-rt] Remove hard-coded dependency on compiler-rt path on Windows (#150244)

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This fixes an issue where if the build folder is no longer present flang
cannot link anything on Windows because the path to compiler-rt in the
binary is hard-coded. Flang already links compiler-rt on Windows so it
isn't necessary for flang-rt to specify that it depends on compiler-rt
at all, other than for the unit tests, so instead we can move that logic
into the unit test compile lines.
This commit is contained in:
David Truby 2025-07-26 14:42:42 +01:00 committed by GitHub
parent 70e0f31747
commit c20a95a7dd
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
2 changed files with 23 additions and 21 deletions
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21
flang-rt/cmake/modules/AddFlangRT.cmake
View File

@ -286,27 +286,6 @@ function (add_flangrt_library name)
target_compile_options(${tgtname} PUBLIC -U_LIBCPP_ENABLE_ASSERTIONS)
endif ()
# Flang/Clang (including clang-cl) -compiled programs targeting the MSVC ABI
# should only depend on msvcrt/ucrt. LLVM still emits libgcc/compiler-rt
# functions in some cases like 128-bit integer math (__udivti3, __modti3,
# __fixsfti, __floattidf, ...) that msvc does not support. We are injecting a
# dependency to Compiler-RT's builtin library where these are implemented.
if (MSVC AND CMAKE_CXX_COMPILER_ID MATCHES "Clang")
if (FLANG_RT_BUILTINS_LIBRARY)
target_compile_options(${tgtname} PRIVATE "$<$<COMPILE_LANGUAGE:CXX,C>:-Xclang>" "$<$<COMPILE_LANGUAGE:CXX,C>:--dependent-lib=${FLANG_RT_BUILTINS_LIBRARY}>")
endif ()
endif ()
if (MSVC AND CMAKE_Fortran_COMPILER_ID STREQUAL "LLVMFlang")
if (FLANG_RT_BUILTINS_LIBRARY)
target_compile_options(${tgtname} PRIVATE "$<$<COMPILE_LANGUAGE:Fortran>:-Xflang>" "$<$<COMPILE_LANGUAGE:Fortran>:--dependent-lib=${FLANG_RT_BUILTINS_LIBRARY}>")
else ()
message(WARNING "Did not find libclang_rt.builtins.lib.
LLVM may emit builtins that are not implemented in msvcrt/ucrt and
instead falls back to builtins from Compiler-RT. Linking with ${tgtname}
may result in a linker error.")
endif ()
endif ()
# Non-GTest unittests depend on LLVMSupport
if (ARG_LINK_TO_LLVM)
if (LLVM_LINK_LLVM_DYLIB)

23
flang-rt/unittests/CMakeLists.txt
View File

@ -60,6 +60,27 @@ function(add_flangrt_unittest_offload_properties target)
endif()
endfunction()
# flang-rt on Windows requires compiler-rt for some symbols. For binaries built
# with flang this dependency is added by the flang driver, but since the unit
# tests are built with clang we need to add the dependency manually.
function(add_flangrt_dependent_libs target)
if (MSVC AND CMAKE_CXX_COMPILER_ID MATCHES "Clang")
if (FLANG_RT_BUILTINS_LIBRARY)
target_compile_options(${target} PRIVATE "$<$<COMPILE_LANGUAGE:CXX,C>:-Xclang>" "$<$<COMPILE_LANGUAGE:CXX,C>:--dependent-lib=${FLANG_RT_BUILTINS_LIBRARY}>")
endif ()
endif ()
if (MSVC AND CMAKE_Fortran_COMPILER_ID STREQUAL "LLVMFlang")
if (FLANG_RT_BUILTINS_LIBRARY)
target_compile_options(${target} PRIVATE "$<$<COMPILE_LANGUAGE:Fortran>:-Xflang>" "$<$<COMPILE_LANGUAGE:Fortran>:--dependent-lib=${FLANG_RT_BUILTINS_LIBRARY}>")
else ()
message(WARNING "Did not find libclang_rt.builtins.lib.
LLVM may emit builtins that are not implemented in msvcrt/ucrt and
instead falls back to builtins from Compiler-RT. Linking with ${tgtname}
may result in a linker error.")
endif ()
endif ()
endfunction()
function(add_flangrt_unittest test_dirname)
cmake_parse_arguments(ARG
@ -72,6 +93,7 @@ function(add_flangrt_unittest test_dirname)
target_link_libraries(${test_dirname} PRIVATE ${ARG_LINK_LIBS})
add_flangrt_unittest_offload_properties(${test_dirname})
add_flangrt_dependent_libs(${test_dirname})
# Required because LLVMSupport is compiled with this option.
# FIXME: According to CMake documentation, this is the default. Why is it
@ -99,6 +121,7 @@ function(add_flangrt_nongtest_unittest test_name)
set_target_properties(${test_name}${suffix} PROPERTIES FOLDER "Flang-RT/Tests/Unit")
target_link_libraries(${test_name}${suffix} PRIVATE NonGTestTesting ${ARG_LINK_LIBS})
add_flangrt_dependent_libs(${test_name}${suffix})
if(NOT ARG_SLOW_TEST)
add_dependencies(FlangRTUnitTests ${test_name}${suffix})