[CMake][Release] Statically link clang with stage1 runtimes #127268
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This change will cause clang and the other tools to statically link against the runtimes built in stage1. This will make the built binaries more portable by eliminating dependencies on system libraries like libgcc and libstdc++.
|
@llvm/pr-subscribers-flang-runtime @llvm/pr-subscribers-clang Author: Tom Stellard (tstellar) ChangesThis change will cause clang and the other tools to statically link against the runtimes built in stage1. This will make the built binaries more portable by eliminating dependencies on system libraries like libgcc and libstdc++. Full diff: https://github.com/llvm/llvm-project/pull/127268.diff 1 Files Affected:
diff --git a/clang/cmake/caches/Release.cmake b/clang/cmake/caches/Release.cmake
index 23e99493087ff..290e186baf6fe 100644
--- a/clang/cmake/caches/Release.cmake
+++ b/clang/cmake/caches/Release.cmake
@@ -48,10 +48,8 @@ set(CLANG_ENABLE_BOOTSTRAP ON CACHE BOOL "")
set(STAGE1_PROJECTS "clang")
-# Building Flang on Windows requires compiler-rt, so we need to build it in
-# stage1. compiler-rt is also required for building the Flang tests on
-# macOS.
-set(STAGE1_RUNTIMES "compiler-rt")
+# Build all runtimes so we can statically link them into the stage2 compiler.
+set(STAGE1_RUNTIMES "compiler-rt;libcxx;libcxxabi;libunwind")
if (LLVM_RELEASE_ENABLE_PGO)
list(APPEND STAGE1_PROJECTS "lld")
@@ -90,9 +88,18 @@ else()
set(CLANG_BOOTSTRAP_TARGETS ${LLVM_RELEASE_FINAL_STAGE_TARGETS} CACHE STRING "")
endif()
+if (LLVM_RELEASE_ENABLE_LTO)
+ # Enable LTO for the runtimes. We need to configure stage1 clang to default
+ # to using lld as the linker because the stage1 toolchain will be used to
+ # build and link the runtimes.
+ set(RUNTIMES_CMAKE_ARGS "-DCMAKE_INTERPROCEDURAL_OPTIMIZATION=ON" CACHE STRING "")
+ set(LLVM_ENABLE_LLD ON CACHE STRING "")
+endif()
+
# Stage 1 Common Config
set(LLVM_ENABLE_RUNTIMES ${STAGE1_RUNTIMES} CACHE STRING "")
set(LLVM_ENABLE_PROJECTS ${STAGE1_PROJECTS} CACHE STRING "")
+set(LIBCXX_STATICALLY_LINK_ABI_IN_STATIC_LIBRARY ON CACHE STRING "")
# stage2-instrumented and Final Stage Config:
# Options that need to be set in both the instrumented stage (if we are doing
@@ -102,6 +109,11 @@ set_instrument_and_final_stage_var(LLVM_ENABLE_LTO "${LLVM_RELEASE_ENABLE_LTO}"
if (LLVM_RELEASE_ENABLE_LTO)
set_instrument_and_final_stage_var(LLVM_ENABLE_LLD "ON" BOOL)
endif()
+set_instrument_and_final_stage_var(LLVM_ENABLE_LIBCXX "ON" BOOL)
+set_instrument_and_final_stage_var(LLVM_STATIC_LINK_CXX_STDLIB "ON" BOOL)
+set_instrument_and_final_stage_var(CMAKE_EXE_LINKER_FLAGS "-rtlib=compiler-rt --unwindlib=libunwind -static-libgcc" STRING)
+set_instrument_and_final_stage_var(CMAKE_SHARED_LINKER_FLAGS "-rtlib=compiler-rt --unwindlib=libunwind -static-libgcc" STRING)
+set_instrument_and_final_stage_var(CMAKE_MODULE_LINKER_FLAGS "-rtlib=compiler-rt --unwindlib=libunwind -static-libgcc" STRING)
# Final Stage Config (stage2)
set_final_stage_var(LLVM_ENABLE_RUNTIMES "${LLVM_RELEASE_ENABLE_RUNTIMES}" STRING)
|
I think this first stopped working with 9548366. This patch fixes the following error: /home/runner/work/llvm-project/llvm-project/flang/runtime/io-api-minimal.cpp:153:11: error: '__libcpp_verbose_abort' is missing exception specification 'noexcept' 153 | void std::__libcpp_verbose_abort(char const *format, ...) { | ^ | noexcept /mnt/build/bin/../include/c++/v1/__verbose_abort:30:28: note: previous declaration is here 30 | __printf__, 1, 2) void __libcpp_verbose_abort(const char* __format, ...) _LIBCPP_VERBOSE_ABORT_NOEXCEPT; | ^ 1 error generated.
llvmbot
added
flang:runtime
flang
|
✅ With the latest revision this PR passed the C/C++ code formatter. |
tru
reviewed
Feb 19, 2025
| # Enable LTO for the runtimes. We need to configure stage1 clang to default | ||
| # to using lld as the linker because the stage1 toolchain will be used to | ||
| # build and link the runtimes. | ||
| set(RUNTIMES_CMAKE_ARGS "-DCMAKE_INTERPROCEDURAL_OPTIMIZATION=ON -DLLVM_ENABLE_LLD=ON" CACHE STRING "") |
There was a problem hiding this comment.
Is there a reason we can't use LLVM_ENABLE_LTO=Thin here? It would be more explicit that we enable ThinLTO over whatever CMake deems good in that case.
There was a problem hiding this comment.
LLVM_ENABLE_LTO=Thin causes some of the CMake checks for the runtime build to fail which fails the whole build. -DCMAKE_INTERPROCEDURAL_OPTIMIZATION=ON does enable ThinLTO, so it's effectively the same.
There was a problem hiding this comment.
That's odd. Maybe we could at least say why we are not using that flag there since that's the one that's documented in the llvm documentation.
tru
approved these changes
Feb 19, 2025
|
/cherry-pick f5b311e |
|
/pull-request #127949 |
swift-ci
pushed a commit
to swiftlang/llvm-project
that referenced
this pull request
Feb 21, 2025
) This change will cause clang and the other tools to statically link against the runtimes built in stage1. This will make the built binaries more portable by eliminating dependencies on system libraries like libgcc and libstdc++. (cherry picked from commit f5b311e)
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This change will cause clang and the other tools to statically link against the runtimes built in stage1. This will make the built binaries more portable by eliminating dependencies on system libraries like libgcc and libstdc++.