https://github.com/arsenm created https://github.com/llvm/llvm-project/pull/205130
After #203504, runtime sub-builds for GPU/baremetal targets are configured with CMAKE_SYSTEM_NAME=Generic rather than inheriting the host's system name. CMake's Platform/Generic.cmake sets the global TARGET_SUPPORTS_SHARED_LIBS property to FALSE, which causes CMake to silently turn SHARED library targets into STATIC ones. libcxx, libcxxabi and libunwind always define their shared library target (gated by EXCLUDE_FROM_ALL) even when *_ENABLE_SHARED is off, and the shared and static targets share the same OUTPUT_NAME. With the shared target demoted to a static archive, both targets generate e.g. "libc++abi.a", which Ninja rejects: ninja: error: build.ninja:147837: multiple rules generate lib/amdgcn-amd-amdhsa/libc++abi.a [-w dupbuild=err] Default the shared library output name to a distinct "-shared" name when the platform does not support shared libraries, mirroring the existing workaround in libcxx/cmake/caches/Armv7M-picolibc.cmake. This makes the GPU and other Generic-targeted runtimes builds configure again. See https://gitlab.kitware.com/cmake/cmake/-/issues/25759. This was generated by AI. This is the quick fix, I have a more comprehensive patch pending. Co-Authored-By: Claude <[email protected]> >From 0ec3a61e79115e885329453718481ed0ad3805e5 Mon Sep 17 00:00:00 2001 From: Matt Arsenault <[email protected]> Date: Mon, 22 Jun 2026 17:25:12 +0200 Subject: [PATCH] [runtimes] Avoid duplicate static archive when shared libs are unsupported After #203504, runtime sub-builds for GPU/baremetal targets are configured with CMAKE_SYSTEM_NAME=Generic rather than inheriting the host's system name. CMake's Platform/Generic.cmake sets the global TARGET_SUPPORTS_SHARED_LIBS property to FALSE, which causes CMake to silently turn SHARED library targets into STATIC ones. libcxx, libcxxabi and libunwind always define their shared library target (gated by EXCLUDE_FROM_ALL) even when *_ENABLE_SHARED is off, and the shared and static targets share the same OUTPUT_NAME. With the shared target demoted to a static archive, both targets generate e.g. "libc++abi.a", which Ninja rejects: ninja: error: build.ninja:147837: multiple rules generate lib/amdgcn-amd-amdhsa/libc++abi.a [-w dupbuild=err] Default the shared library output name to a distinct "-shared" name when the platform does not support shared libraries, mirroring the existing workaround in libcxx/cmake/caches/Armv7M-picolibc.cmake. This makes the GPU and other Generic-targeted runtimes builds configure again. See https://gitlab.kitware.com/cmake/cmake/-/issues/25759. This was generated by AI. This is the quick fix, I have a more comprehensive patch pending. Co-Authored-By: Claude <[email protected]> --- libcxx/CMakeLists.txt | 16 +++++++++++++++- libcxxabi/CMakeLists.txt | 16 +++++++++++++++- libunwind/CMakeLists.txt | 16 +++++++++++++++- 3 files changed, 45 insertions(+), 3 deletions(-) diff --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt index 845240d1b894c..72f1eda6393e6 100644 --- a/libcxx/CMakeLists.txt +++ b/libcxx/CMakeLists.txt @@ -445,7 +445,21 @@ set(LIBCXX_INSTALL_RUNTIME_DIR "${CMAKE_INSTALL_BINDIR}" CACHE STRING set(LIBCXX_INSTALL_MODULES_DIR "share/libc++/v1" CACHE STRING "Path where target-agnostic libc++ module source files should be installed.") -set(LIBCXX_SHARED_OUTPUT_NAME "c++" CACHE STRING "Output name for the shared libc++ runtime library.") +# On platforms that don't support shared library targets (e.g. CMAKE_SYSTEM_NAME +# of "Generic", used for GPU and other baremetal targets), CMake implicitly +# changes shared library targets into static library targets. The shared target +# is always defined even when LIBCXX_ENABLE_SHARED is off, so this would result +# in two targets producing the same "libc++.a" output and break the build. Give +# the shared library a different default output name in that case so it can't +# collide with the static library. +# See https://gitlab.kitware.com/cmake/cmake/-/issues/25759. +get_property(LIBCXX_TARGET_SUPPORTS_SHARED_LIBS GLOBAL PROPERTY TARGET_SUPPORTS_SHARED_LIBS) +if(DEFINED LIBCXX_TARGET_SUPPORTS_SHARED_LIBS AND NOT LIBCXX_TARGET_SUPPORTS_SHARED_LIBS) + set(LIBCXX_DEFAULT_SHARED_OUTPUT_NAME "c++-shared") +else() + set(LIBCXX_DEFAULT_SHARED_OUTPUT_NAME "c++") +endif() +set(LIBCXX_SHARED_OUTPUT_NAME "${LIBCXX_DEFAULT_SHARED_OUTPUT_NAME}" CACHE STRING "Output name for the shared libc++ runtime library.") set(LIBCXX_STATIC_OUTPUT_NAME "c++" CACHE STRING "Output name for the static libc++ runtime library.") # TODO: Use common runtimes infrastructure for output and install paths diff --git a/libcxxabi/CMakeLists.txt b/libcxxabi/CMakeLists.txt index e1a1587fb6283..f6ad2e1bf314a 100644 --- a/libcxxabi/CMakeLists.txt +++ b/libcxxabi/CMakeLists.txt @@ -89,7 +89,21 @@ set(LIBCXXABI_LIBDIR_SUFFIX "${LLVM_LIBDIR_SUFFIX}" CACHE STRING option(LIBCXXABI_INSTALL_HEADERS "Install the libc++abi headers." ON) option(LIBCXXABI_INSTALL_LIBRARY "Install the libc++abi library." ON) -set(LIBCXXABI_SHARED_OUTPUT_NAME "c++abi" CACHE STRING "Output name for the shared libc++abi runtime library.") +# On platforms that don't support shared library targets (e.g. CMAKE_SYSTEM_NAME +# of "Generic", used for GPU and other baremetal targets), CMake implicitly +# changes shared library targets into static library targets. The shared target +# is always defined even when LIBCXXABI_ENABLE_SHARED is off, so this would +# result in two targets producing the same "libc++abi.a" output and break the +# build. Give the shared library a different default output name in that case so +# it can't collide with the static library. +# See https://gitlab.kitware.com/cmake/cmake/-/issues/25759. +get_property(LIBCXXABI_TARGET_SUPPORTS_SHARED_LIBS GLOBAL PROPERTY TARGET_SUPPORTS_SHARED_LIBS) +if(DEFINED LIBCXXABI_TARGET_SUPPORTS_SHARED_LIBS AND NOT LIBCXXABI_TARGET_SUPPORTS_SHARED_LIBS) + set(LIBCXXABI_DEFAULT_SHARED_OUTPUT_NAME "c++abi-shared") +else() + set(LIBCXXABI_DEFAULT_SHARED_OUTPUT_NAME "c++abi") +endif() +set(LIBCXXABI_SHARED_OUTPUT_NAME "${LIBCXXABI_DEFAULT_SHARED_OUTPUT_NAME}" CACHE STRING "Output name for the shared libc++abi runtime library.") set(LIBCXXABI_STATIC_OUTPUT_NAME "c++abi" CACHE STRING "Output name for the static libc++abi runtime library.") set(LIBCXXABI_INSTALL_INCLUDE_DIR "${CMAKE_INSTALL_INCLUDEDIR}/c++/v1" CACHE STRING "Path to install the libc++abi headers at.") diff --git a/libunwind/CMakeLists.txt b/libunwind/CMakeLists.txt index 02132f6c07fcd..65dabf605f252 100644 --- a/libunwind/CMakeLists.txt +++ b/libunwind/CMakeLists.txt @@ -137,7 +137,21 @@ set(LIBUNWIND_INSTALL_INCLUDE_DIR "${CMAKE_INSTALL_INCLUDEDIR}" CACHE STRING set(LIBUNWIND_INSTALL_RUNTIME_DIR "${CMAKE_INSTALL_BINDIR}" CACHE STRING "Path where built libunwind runtime libraries should be installed.") -set(LIBUNWIND_SHARED_OUTPUT_NAME "unwind" CACHE STRING "Output name for the shared libunwind runtime library.") +# On platforms that don't support shared library targets (e.g. CMAKE_SYSTEM_NAME +# of "Generic", used for GPU and other baremetal targets), CMake implicitly +# changes shared library targets into static library targets. The shared target +# is always defined even when LIBUNWIND_ENABLE_SHARED is off, so this would +# result in two targets producing the same "libunwind.a" output and break the +# build. Give the shared library a different default output name in that case so +# it can't collide with the static library. +# See https://gitlab.kitware.com/cmake/cmake/-/issues/25759. +get_property(LIBUNWIND_TARGET_SUPPORTS_SHARED_LIBS GLOBAL PROPERTY TARGET_SUPPORTS_SHARED_LIBS) +if(DEFINED LIBUNWIND_TARGET_SUPPORTS_SHARED_LIBS AND NOT LIBUNWIND_TARGET_SUPPORTS_SHARED_LIBS) + set(LIBUNWIND_DEFAULT_SHARED_OUTPUT_NAME "unwind-shared") +else() + set(LIBUNWIND_DEFAULT_SHARED_OUTPUT_NAME "unwind") +endif() +set(LIBUNWIND_SHARED_OUTPUT_NAME "${LIBUNWIND_DEFAULT_SHARED_OUTPUT_NAME}" CACHE STRING "Output name for the shared libunwind runtime library.") set(LIBUNWIND_STATIC_OUTPUT_NAME "unwind" CACHE STRING "Output name for the static libunwind runtime library.") # TODO: Use common runtimes infrastructure for output and install paths _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
