[llvm-branch-commits] [clang] [llvm] release/20.x: [CMake][Release] Enable bolt optimization for clang on Linux (#128090) (PR #128730)

[via llvm-branch-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-github-workflow

Author: None (llvmbot)

<details>
<summary>Changes</summary>

Backport 148111fdcf0e807fe74274b18fcf65c4cff45d63

Requested by: @<!-- -->tstellar

---
Full diff: https://github.com/llvm/llvm-project/pull/128730.diff


2 Files Affected:

- (modified) .github/workflows/release-binaries.yml (+1-1) 
- (modified) clang/cmake/caches/Release.cmake (+16-1) 


``````````diff
diff --git a/.github/workflows/release-binaries.yml b/.github/workflows/release-binaries.yml
index fa3dfa5b7d313..a18f64d6bc226 100644
--- a/.github/workflows/release-binaries.yml
+++ b/.github/workflows/release-binaries.yml
@@ -142,7 +142,7 @@ jobs:
             # 2-3 hours to build on macOS, much slower than on Linux.
             # The long build time causes the release build to time out on x86_64,
             # so we need to disable flang there.
-            target_cmake_flags="$target_cmake_flags -DLLVM_RELEASE_ENABLE_PROJECTS='clang;lld;lldb;clang-tools-extra;bolt;polly;mlir'"
+            target_cmake_flags="$target_cmake_flags -DLLVM_RELEASE_ENABLE_PROJECTS='clang;lld;lldb;clang-tools-extra;polly;mlir'"
           fi
           target_cmake_flags="$target_cmake_flags -DBOOTSTRAP_DARWIN_osx_ARCHS=$arches -DBOOTSTRAP_DARWIN_osx_BUILTIN_ARCHS=$arches"
         fi
diff --git a/clang/cmake/caches/Release.cmake b/clang/cmake/caches/Release.cmake
index a1c68fc51dbd0..aedbd1a25fb38 100644
--- a/clang/cmake/caches/Release.cmake
+++ b/clang/cmake/caches/Release.cmake
@@ -29,6 +29,13 @@ endfunction()
 # cache file to CMake via -C. e.g.
 #
 # cmake -D LLVM_RELEASE_ENABLE_PGO=ON -C Release.cmake
+
+set (DEFAULT_PROJECTS "clang;lld;lldb;clang-tools-extra;polly;mlir;flang")
+# bolt only supports ELF, so only enable it for Linux.
+if (${CMAKE_HOST_SYSTEM_NAME} MATCHES "Linux")
+  list(APPEND DEFAULT_PROJECTS "bolt")
+endif()
+
 set (DEFAULT_RUNTIMES "compiler-rt;libcxx")
 if (NOT WIN32)
   list(APPEND DEFAULT_RUNTIMES "libcxxabi" "libunwind")
@@ -36,7 +43,7 @@ endif()
 set(LLVM_RELEASE_ENABLE_LTO THIN CACHE STRING "")
 set(LLVM_RELEASE_ENABLE_PGO ON CACHE BOOL "")
 set(LLVM_RELEASE_ENABLE_RUNTIMES ${DEFAULT_RUNTIMES} CACHE STRING "")
-set(LLVM_RELEASE_ENABLE_PROJECTS "clang;lld;lldb;clang-tools-extra;bolt;polly;mlir;flang" CACHE STRING "")
+set(LLVM_RELEASE_ENABLE_PROJECTS ${DEFAULT_PROJECTS} CACHE STRING "")
 # Note we don't need to add install here, since it is one of the pre-defined
 # steps.
 set(LLVM_RELEASE_FINAL_STAGE_TARGETS "clang;package;check-all;check-llvm;check-clang" CACHE STRING "")
@@ -118,6 +125,11 @@ if(NOT ${CMAKE_HOST_SYSTEM_NAME} MATCHES "Darwin")
   set(RELEASE_LINKER_FLAGS "${RELEASE_LINKER_FLAGS} -static-libgcc")
 endif()
 
+# Set flags for bolt
+if (${CMAKE_HOST_SYSTEM_NAME} MATCHES "Linux")
+  set(RELEASE_LINKER_FLAGS "${RELEASE_LINKER_FLAGS} -Wl,--emit-relocs,-znow")
+endif()
+
 set_instrument_and_final_stage_var(CMAKE_EXE_LINKER_FLAGS ${RELEASE_LINKER_FLAGS} STRING)
 set_instrument_and_final_stage_var(CMAKE_SHARED_LINKER_FLAGS ${RELEASE_LINKER_FLAGS} STRING)
 set_instrument_and_final_stage_var(CMAKE_MODULE_LINKER_FLAGS ${RELEASE_LINKER_FLAGS} STRING)
@@ -125,6 +137,9 @@ set_instrument_and_final_stage_var(CMAKE_MODULE_LINKER_FLAGS ${RELEASE_LINKER_FL
 # Final Stage Config (stage2)
 set_final_stage_var(LLVM_ENABLE_RUNTIMES "${LLVM_RELEASE_ENABLE_RUNTIMES}" STRING)
 set_final_stage_var(LLVM_ENABLE_PROJECTS "${LLVM_RELEASE_ENABLE_PROJECTS}" STRING)
+if (${CMAKE_HOST_SYSTEM_NAME} MATCHES "Linux")
+  set_final_stage_var(CLANG_BOLT "INSTRUMENT" STRING)
+endif()
 set_final_stage_var(CPACK_GENERATOR "TXZ" STRING)
 set_final_stage_var(CPACK_ARCHIVE_THREADS "0" STRING)
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/128730