Skip to content

[CMake][Release] Stop linking against stage1 runtimes #164017

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 2 commits into
base: main
Choose a base branch
from
Open

[CMake][Release] Stop linking against stage1 runtimes #164017

Changes from 1 commit
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
e0d52ed
[CMake][Release] Stop linking against stage1 runtimes
tstellar Oct 15, 2025
d0753d8
Change variable name
tstellar Oct 20, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
39 changes: 30 additions & 9 deletions clang/cmake/caches/Release.cmake
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,19 @@ 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 ${DEFAULT_PROJECTS} CACHE STRING "")

# This option enables linking stage2 clang statically with the runtimes
# (libc++ and compiler-rt) from stage1. In theory this will give the
# binaries better performance and make them more portable. However,
# this configuration is not well tested and causes build failures with
# the flang-rt tests cases, since the -stclib=libc++ flag does not
# get propagated to the runtimes build. There is also a separate
# issue on Darwin where clang will use the local libc++ headers, but
# link with system libc++ which can cause some incompatibilities.
# See https://github.com/llvm/llvm-project/issues/77653
# Because of these problems, this option will default to OFF.
set(LLVM_RELEASE_LINK_LOCAL_RUNTIMES OFF CACHE BOOL "")
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

nit:

Suggested change
set(LLVM_RELEASE_LINK_LOCAL_RUNTIMES OFF CACHE BOOL "")
set(LLVM_RELEASE_ENABLE_LINK_LOCAL_RUNTIMES OFF CACHE BOOL "")


# 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 "")
Expand All @@ -55,8 +68,12 @@ set(CLANG_ENABLE_BOOTSTRAP ON CACHE BOOL "")

set(STAGE1_PROJECTS "clang")

# Need to build compiler-rt in order to use PGO for later stages.
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_LINK_LOCAL_RUNTIMES)
list(APPEND STAGE1_RUNTIMES "libcxx;libcxxabi;libunwind")
endif()

if (LLVM_RELEASE_ENABLE_PGO)
list(APPEND STAGE1_PROJECTS "lld")
Expand Down Expand Up @@ -118,21 +135,25 @@ 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(RELEASE_LINKER_FLAGS "-rtlib=compiler-rt --unwindlib=libunwind")
if(NOT ${CMAKE_HOST_SYSTEM_NAME} MATCHES "Darwin")
set(RELEASE_LINKER_FLAGS "${RELEASE_LINKER_FLAGS} -static-libgcc")
if(LLVM_RELEASE_LINK_LOCAL_RUNTIMES)
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(RELEASE_LINKER_FLAGS "-rtlib=compiler-rt --unwindlib=libunwind")
if(NOT ${CMAKE_HOST_SYSTEM_NAME} MATCHES "Darwin")
set(RELEASE_LINKER_FLAGS "${RELEASE_LINKER_FLAGS} -static-libgcc")
endif()
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)
if (RELEASE_LINKER_FLAGS)
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)
endif()

# Final Stage Config (stage2)
set_final_stage_var(LLVM_ENABLE_RUNTIMES "${LLVM_RELEASE_ENABLE_RUNTIMES}" STRING)
Expand Down
Loading