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[llvm-libgcc][CMake] Refactor llvm-libgcc #65455

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Merged
merged 8 commits into from
Sep 19, 2023
Merged

[llvm-libgcc][CMake] Refactor llvm-libgcc #65455

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eb938ef
[llvm-libgcc][CMake] Fix broken libgcc_s.so
ur4t Aug 17, 2023
1b8a9ba
[llvm-libgcc][CMake] Refactor llvm-libgcc CMakeLists
ur4t Aug 19, 2023
c790fd0
[llvm-libgcc][CMake] Fix mismatched target names of llvm-libgcc
ur4t Sep 7, 2023
358ff00
[llvm-libgcc][CMake] Refuse improper COMPILER_RT_BUILD_BUILTINS
ur4t Sep 7, 2023
6f7088b
[llvm-libgcc][CMake] Fix broken component llvm-libgcc
ur4t Sep 8, 2023
b61aed7
[llvm-libgcc][CMake] Restore to inhibit co-existence of llvm-libgcc a…
ur4t Sep 8, 2023
656d900
[llvm-libgcc][CMake] Remove uncessary dependency on compiler-rt or li…
ur4t Sep 8, 2023
60eccd0
[llvm-libgcc][CMake] Improve standalone build for llvm-libgcc
ur4t Sep 13, 2023
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153 changes: 134 additions & 19 deletions llvm-libgcc/CMakeLists.txt
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Original file line number Diff line number Diff line change
@@ -1,19 +1,38 @@
cmake_minimum_required(VERSION 3.20.0)
#===============================================================================
# Setup Project
#===============================================================================

if (NOT IS_DIRECTORY "${CMAKE_CURRENT_LIST_DIR}/../libunwind")
message(FATAL_ERROR "llvm-libgcc requires being built in a monorepo layout with libunwind available")
endif()
cmake_minimum_required(VERSION 3.20.0)

set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")

list(APPEND CMAKE_MODULE_PATH
# Check if llvm-libgcc is built as a standalone project
if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR OR LLVM_LIBGCC_STANDALONE_BUILD)
project(llvm-libgcc LANGUAGES C CXX ASM)
set(COMPILER_RT_STANDALONE_BUILD ON)
set_property(GLOBAL PROPERTY USE_FOLDERS ON)
set(LLVM_LIBGCC_COMPILER_RT_BINARY_DIR "compiler-rt")
set(LLVM_LIBGCC_LIBUNWIND_BINARY_DIR "libunwind")
else()
set(LLVM_LIBGCC_COMPILER_RT_BINARY_DIR "../compiler-rt")
set(LLVM_LIBGCC_LIBUNWIND_BINARY_DIR "../libunwind")
endif()

# Add path for custom modules
list(INSERT CMAKE_MODULE_PATH 0
"${CMAKE_CURRENT_SOURCE_DIR}/cmake"
"${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules"
"${CMAKE_CURRENT_SOURCE_DIR}/../runtimes/cmake/Modules"
"${LLVM_COMMON_CMAKE_UTILS}"
"${LLVM_COMMON_CMAKE_UTILS}/Modules"
)
)

set(LLVM_LIBGCC_LIBUNWIND_PATH "${CMAKE_CURRENT_LIST_DIR}/../libunwind"
CACHE PATH "Specify path to libunwind source.")
set(LLVM_LIBGCC_COMPILER_RT_PATH "${CMAKE_CURRENT_LIST_DIR}/../compiler-rt"
CACHE PATH "Specify path to compiler-rt source.")

project(llvm-libgcc LANGUAGES C CXX ASM)
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Why is this being removed?

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libunwind/CMakeLists.txt does not contains a project(libunwind LANGUAGES C CXX ASM). To keep consistent with libunwind/CMakeLists.txt, project(llvm-libgcc LANGUAGES C CXX ASM) is not added.

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compiler-rt does have it, and I'd prefer to keep this regardless.

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Now llvm-libgcc use the same approach as compiler-rt in 60eccd0.

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I'm not following what you mean, sorry. Since this is the driver for compiler-rt and libunwind, it makes sense to me for this project to indicate this information.

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compiler-rt/CMakeLists.txt detects whether compiler-rt is built as a subproject of runtimes or a standalone project. In standalone mode it sets options to detect llvm and declares the project name with project(CompilerRT C CXX ASM).

Now llvm-libgcc/CMakeLists.txt does the same: in standalone mode, it tells added compiler-rt that we are not built as a subproject of runtimes and we have to detect llvm ourselves.

Here "standalone" means cmake -B build -S compiler-rt or cmake -B build -S llvm-libgcc, not cmake -B build -S runtimes nor cmake -B build -S llvm. Even in the whole llvm-project source tree, directly using compiler-rt/CMakeLists.txt or llvm-libgcc/CMakeLists.txt is "standalone".

If included by other CMakeLists.txt, runtimes/CMakeLists.txt for example, it does not matter whether there is a project(CompilerRT C CXX ASM) or project(llvm-libgcc LANGUAGES C CXX ASM) declaration actually performed. To keep consistent with compiler-rt, llvm-libgcc/CMakeLists.txt is adjusted correspondingly in 60eccd0.

Correspondingly lines from compiler-rt/CMakeLists.txt :

# Check if compiler-rt is built as a standalone project.
if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR OR COMPILER_RT_STANDALONE_BUILD)
  project(CompilerRT C CXX ASM)
  set(COMPILER_RT_STANDALONE_BUILD TRUE)
  set_property(GLOBAL PROPERTY USE_FOLDERS ON)
endif()

Correspondingly lines in llvm-libgcc/CMakeLists.txt:

# Check if llvm-libgcc is built as a standalone project
if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR OR LLVM_LIBGCC_STANDALONE_BUILD)
  project(llvm-libgcc LANGUAGES C CXX ASM)
  set(COMPILER_RT_STANDALONE_BUILD ON)
  set_property(GLOBAL PROPERTY USE_FOLDERS ON)
  set(LLVM_LIBGCC_COMPILER_RT_BINARY_DIR "compiler-rt")
  set(LLVM_LIBGCC_LIBUNWIND_BINARY_DIR "libunwind")
else()
  set(LLVM_LIBGCC_COMPILER_RT_BINARY_DIR "../compiler-rt")
  set(LLVM_LIBGCC_LIBUNWIND_BINARY_DIR "../libunwind")
endif()

And I am a bit confused how should we indicate "this is the driver for compiler-rt and libunwind". It is completely acceptable to perform project(llvm-libgcc LANGUAGES C CXX ASM) declaration unconditionally, but does it makes sense in this scenario?

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Understood, thanks for highlighting the change to llvm-libgcc/CMakeLists.txt, which I'd missed.

include(GNUInstallDirs)

if(NOT LLVM_LIBGCC_EXPLICIT_OPT_IN)
message(FATAL_ERROR
Expand All @@ -25,18 +44,114 @@ if(NOT LLVM_LIBGCC_EXPLICIT_OPT_IN)
"to your CMake invocation and try again.")
endif()

set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY "${PROJECT_BINARY_DIR}/lib${LLVMLIB_DIR_SUFFIX}")
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY "${PROJECT_BINARY_DIR}/lib${LLVMLIB_DIR_SUFFIX}")
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY "${PROJECT_BINARY_DIR}/bin")
if(HAVE_COMPILER_RT)
message(FATAL_ERROR
"Attempting to build both compiler-rt and llvm-libgcc will cause irreconcilable "
"target clashes. Please choose one or the other, but not both.")
endif()

if(HAVE_LIBUNWIND)
message(FATAL_ERROR
"Attempting to build both libunwind and llvm-libgcc will cause irreconcilable "
"target clashes. Please choose one or the other, but not both.")
endif()

#===============================================================================
# Configure System
#===============================================================================

if(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR AND NOT APPLE)
set(LLVM_LIBGCC_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR}/${LLVM_DEFAULT_TARGET_TRIPLE})
set(LLVM_LIBGCC_INSTALL_LIBRARY_DIR lib${LLVM_LIBDIR_SUFFIX}/${LLVM_DEFAULT_TARGET_TRIPLE} CACHE PATH
"Path where built llvm-libgcc libraries should be installed.")
if(LIBCXX_LIBDIR_SUBDIR)
string(APPEND LLVM_LIBGCC_LIBRARY_DIR /${LLVM_LIBGCC_LIBDIR_SUBDIR})
string(APPEND LLVM_LIBGCC_INSTALL_LIBRARY_DIR /${LLVM_LIBGCC_LIBDIR_SUBDIR})
endif()
else()
if(LLVM_LIBRARY_OUTPUT_INTDIR)
set(LLVM_LIBGCC_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR})
else()
set(LLVM_LIBGCC_LIBRARY_DIR ${CMAKE_BINARY_DIR}/lib${LLVM_LIBGCC_LIBDIR_SUFFIX})
endif()
set(LLVM_LIBGCC_INSTALL_LIBRARY_DIR lib${LLVM_LIBGCC_LIBDIR_SUFFIX} CACHE PATH
"Path where built llvm-libgcc libraries should be installed.")
endif()

set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${LLVM_LIBGCC_LIBRARY_DIR})
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${LLVM_LIBGCC_LIBRARY_DIR})
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${LLVM_LIBGCC_LIBRARY_DIR})

#===============================================================================
# Build libraries
#===============================================================================

set(COMPILER_RT_BUILD_BUILTINS ON)
set(COMPILER_RT_BUILTINS_HIDE_SYMBOLS OFF)
add_subdirectory(${LLVM_LIBGCC_COMPILER_RT_PATH} ${LLVM_LIBGCC_COMPILER_RT_BINARY_DIR})

set(LIBUNWIND_ENABLE_STATIC ON)
set(LIBUNWIND_ENABLE_SHARED ON)
set(LIBUNWIND_USE_COMPILER_RT OFF)
set(LIBUNWIND_HAS_GCC_LIB OFF)
set(LIBUNWIND_HAS_GCC_S_LIB OFF)
add_subdirectory(${LLVM_LIBGCC_LIBUNWIND_PATH} ${LLVM_LIBGCC_LIBUNWIND_BINARY_DIR})

add_custom_target(gcc_s.ver
SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/gcc_s.ver.in
COMMAND ${CMAKE_C_COMPILER} -E
-xc ${CMAKE_CURRENT_SOURCE_DIR}/gcc_s.ver.in
-o ${CMAKE_CURRENT_BINARY_DIR}/gcc_s.ver
)

add_dependencies(unwind_shared gcc_s.ver)

construct_compiler_rt_default_triple()

target_link_options(unwind_shared PUBLIC
-Wl,--version-script,${CMAKE_CURRENT_BINARY_DIR}/gcc_s.ver
)

target_link_libraries(unwind_shared PUBLIC
$<TARGET_OBJECTS:clang_rt.builtins-${COMPILER_RT_DEFAULT_TARGET_ARCH}>
m
)

#===============================================================================
# Install Symlinks
#===============================================================================

get_compiler_rt_install_dir(${COMPILER_RT_DEFAULT_TARGET_ARCH} install_dir_builtins)
string(REGEX REPLACE "^lib/" "" install_dir_builtins "${install_dir_builtins}")
string(FIND "${install_dir_builtins}" "clang" install_path_contains_triple)
if(install_path_contains_triple EQUAL -1)
set(builtins_suffix "-${COMPILER_RT_DEFAULT_TARGET_ARCH}")
else()
string(PREPEND install_dir_builtins "../")
endif()
set(LLVM_LIBGCC_COMPILER_RT ${install_dir_builtins}/libclang_rt.builtins${builtins_suffix}.a)

add_custom_target(llvm-libgcc ALL
DEPENDS unwind_shared unwind_static clang_rt.builtins-${COMPILER_RT_DEFAULT_TARGET_ARCH}
COMMAND ${CMAKE_COMMAND} -E create_symlink ${LLVM_LIBGCC_COMPILER_RT} libgcc.a
COMMAND ${CMAKE_COMMAND} -E create_symlink libunwind.a libgcc_eh.a
COMMAND ${CMAKE_COMMAND} -E create_symlink libunwind.so libgcc_s.so.1.0
COMMAND ${CMAKE_COMMAND} -E create_symlink libgcc_s.so.1.0 libgcc_s.so.1
COMMAND ${CMAKE_COMMAND} -E create_symlink libgcc_s.so.1 libgcc_s.so
)

set(COMPILER_RT_BUILD_BUILTINS On)
set(COMPILER_RT_BUILTINS_HIDE_SYMBOLS Off)
add_subdirectory("../compiler-rt" "compiler-rt")
install(TARGETS unwind_shared unwind_static
LIBRARY DESTINATION ${LLVM_LIBGCC_INSTALL_LIBRARY_DIR} COMPONENT llvm-libgcc
ARCHIVE DESTINATION ${LLVM_LIBGCC_INSTALL_LIBRARY_DIR} COMPONENT llvm-libgcc
RUNTIME DESTINATION ${LLVM_LIBGCC_INSTALL_RUNTIME_DIR} COMPONENT llvm-libgcc)

set(LIBUNWIND_ENABLE_STATIC On)
set(LIBUNWIND_ENABLE_SHARED Off)
set(LIBUNWIND_HAS_COMMENT_LIB_PRAGMA Off)
set(LIBUNWIND_USE_COMPILER_RT On)
add_subdirectory("../libunwind" "libunwind")
install(TARGETS clang_rt.builtins-${COMPILER_RT_DEFAULT_TARGET_ARCH}
LIBRARY DESTINATION ${LLVM_LIBGCC_INSTALL_LIBRARY_DIR}/${install_dir_builtins} COMPONENT llvm-libgcc
ARCHIVE DESTINATION ${LLVM_LIBGCC_INSTALL_LIBRARY_DIR}/${install_dir_builtins} COMPONENT llvm-libgcc
RUNTIME DESTINATION ${LLVM_LIBGCC_INSTALL_RUNTIME_DIR}/${install_dir_builtins} COMPONENT llvm-libgcc)

add_subdirectory(lib)
foreach(VAR libgcc.a libgcc_eh.a libgcc_s.so.1.0 libgcc_s.so.1 libgcc_s.so)
install(FILES ${CMAKE_CURRENT_BINARY_DIR}/${VAR}
DESTINATION ${LLVM_LIBGCC_INSTALL_LIBRARY_DIR}
COMPONENT llvm-libgcc)
endforeach()
0 llvm-libgcc/lib/gcc_s.ver → llvm-libgcc/gcc_s.ver.in
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86 changes: 0 additions & 86 deletions llvm-libgcc/lib/CMakeLists.txt
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This file was deleted.

Empty file removed llvm-libgcc/lib/blank.c
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17 changes: 0 additions & 17 deletions runtimes/CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -212,23 +212,6 @@ if(LLVM_INCLUDE_TESTS)
umbrella_lit_testsuite_begin(check-runtimes)
endif()

# llvm-libgcc incorporates both compiler-rt and libunwind as subprojects with very
# specific flags, which causes clashes when they're independently built too.
if("llvm-libgcc" IN_LIST runtimes)
if("compiler-rt" IN_LIST runtimes OR "compiler-rt" IN_LIST LLVM_ENABLE_PROJECTS)
message(FATAL_ERROR
"Attempting to build both compiler-rt and llvm-libgcc will cause irreconcilable "
"target clashes. Please choose one or the other, but not both.")
endif()

if("libunwind" IN_LIST runtimes)
message(
FATAL_ERROR
"Attempting to build both libunwind and llvm-libgcc will cause irreconcilable "
"target clashes. Please choose one or the other, but not both.")
endif()
endif()

# We do this in two loops so that HAVE_* is set for each runtime before the
# other runtimes are added.
foreach(entry ${runtimes})
Expand Down