Merge commit '8f90e6937a1f' from llvm.org/main into next

Author: git apple-llvm automerger

.github/workflows/libcxx-build-and-test.yaml

@@ -163,7 +163,6 @@ jobs:
           'generic-no-rtti',
           'generic-optimized-speed',
           'generic-static',
-          'generic-with_llvm_unwinder',
           # TODO Find a better place for the benchmark and bootstrapping builds to live. They're either very expensive
           # or don't provide much value since the benchmark run results are too noise on the bots.
           'benchmarks',

libcxx/CMakeLists.txt

@@ -274,7 +274,7 @@ option(LIBCXX_ENABLE_NEW_DELETE_DEFINITIONS
    libc++abi. Doing otherwise is an ODR violation." OFF)
 # Build libc++abi with libunwind. We need this option to determine whether to
 # link with libunwind or libgcc_s while running the test cases.
-option(LIBCXXABI_USE_LLVM_UNWINDER "Build and use the LLVM unwinder." OFF)
+option(LIBCXXABI_USE_LLVM_UNWINDER "Build and use the LLVM unwinder." ON)
 
 # Target options --------------------------------------------------------------
 option(LIBCXX_BUILD_32_BITS "Build 32 bit multilib libc++. This option is not supported anymore when building the runtimes. Please specify a full triple instead." ${LLVM_BUILD_32_BITS})

libcxx/cmake/caches/AArch64.cmake

@@ -1,2 +1 @@
-set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
 set(CMAKE_CXX_COMPILER_TARGET "aarch64-linux-gnu" CACHE STRING "")

libcxx/cmake/caches/AIX.cmake

@@ -13,6 +13,5 @@ set(LIBCXX_ENABLE_STATIC OFF CACHE BOOL "")
 set(LIBCXXABI_ENABLE_SHARED ON CACHE BOOL "")
 set(LIBCXXABI_ENABLE_STATIC OFF CACHE BOOL "")
 set(LIBCXX_CXX_ABI libcxxabi CACHE STRING "")
-set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
 set(LIBUNWIND_ENABLE_SHARED ON CACHE BOOL "")
 set(LIBUNWIND_ENABLE_STATIC OFF CACHE BOOL "")

libcxx/cmake/caches/AndroidNDK.cmake

@@ -22,6 +22,9 @@ set(LIBCXX_ENABLE_ABI_LINKER_SCRIPT OFF CACHE BOOL "")
 set(LIBCXX_STATICALLY_LINK_ABI_IN_SHARED_LIBRARY ON CACHE BOOL "")
 set(LIBCXXABI_ENABLE_SHARED OFF CACHE BOOL "")
 
+# Android uses its own unwinder library
+set(LIBCXXABI_USE_LLVM_UNWINDER OFF CACHE BOOL "")
+
 # Clang links libc++ by default, but it doesn't exist yet. The libc++ CMake
 # files specify -nostdlib++ to avoid this problem, but CMake's default "compiler
 # works" testing doesn't pass that flag, so force those tests to pass.

libcxx/cmake/caches/Apple.cmake

@@ -14,6 +14,7 @@ set(LIBCXXABI_HERMETIC_STATIC_LIBRARY ON CACHE BOOL "")
 
 set(LIBCXXABI_ENABLE_ASSERTIONS OFF CACHE BOOL "")
 set(LIBCXXABI_ENABLE_FORGIVING_DYNAMIC_CAST ON CACHE BOOL "")
+set(LIBCXXABI_USE_LLVM_UNWINDER OFF CACHE BOOL "") # libunwind is built separately
 
 set(LIBCXX_TEST_CONFIG "apple-libc++-shared.cfg.in" CACHE STRING "")
 set(LIBCXXABI_TEST_CONFIG "apple-libc++abi-shared.cfg.in" CACHE STRING "")

libcxx/cmake/caches/Armv7Arm.cmake

@@ -1,4 +1,3 @@
-set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
 set(CMAKE_CXX_COMPILER_TARGET "armv7l-linux-gnueabihf" CACHE STRING "")
 set(CMAKE_CXX_FLAGS "-marm" CACHE STRING "")
 set(CMAKE_C_FLAGS "-marm" CACHE STRING "")

libcxx/cmake/caches/Armv7M-picolibc.cmake

@@ -19,7 +19,6 @@ set(LIBCXXABI_ENABLE_STATIC ON CACHE BOOL "")
 set(LIBCXXABI_ENABLE_STATIC_UNWINDER ON CACHE BOOL "")
 set(LIBCXXABI_ENABLE_THREADS OFF CACHE BOOL "")
 set(LIBCXXABI_USE_COMPILER_RT ON CACHE BOOL "")
-set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
 set(LIBCXX_ENABLE_EXCEPTIONS ON CACHE BOOL "")
 set(LIBCXX_ENABLE_FILESYSTEM OFF CACHE STRING "")
 set(LIBCXX_ENABLE_MONOTONIC_CLOCK OFF CACHE BOOL "")

libcxx/cmake/caches/Armv7Thumb-no-exceptions.cmake

@@ -1,4 +1,3 @@
-set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
 set(CMAKE_CXX_COMPILER_TARGET "armv7l-linux-gnueabihf" CACHE STRING "")
 set(CMAKE_CXX_FLAGS "-mthumb" CACHE STRING "")
 set(CMAKE_C_FLAGS "-mthumb" CACHE STRING "")

libcxx/cmake/caches/Armv8Arm.cmake

@@ -1,4 +1,3 @@
-set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
 set(CMAKE_CXX_COMPILER_TARGET "armv8l-linux-gnueabihf" CACHE STRING "")
 set(CMAKE_CXX_FLAGS "-marm" CACHE STRING "")
 set(CMAKE_C_FLAGS "-marm" CACHE STRING "")

libcxx/cmake/caches/Armv8Thumb-no-exceptions.cmake

@@ -1,4 +1,3 @@
-set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
 set(CMAKE_CXX_COMPILER_TARGET "armv8l-linux-gnueabihf" CACHE STRING "")
 set(CMAKE_CXX_FLAGS "-mthumb" CACHE STRING "")
 set(CMAKE_C_FLAGS "-mthumb" CACHE STRING "")

libcxx/cmake/caches/Generic-merged.cmake

@@ -5,7 +5,6 @@ set(LIBCXX_ENABLE_STATIC_ABI_LIBRARY ON CACHE BOOL "")
 set(LIBCXX_STATICALLY_LINK_ABI_IN_SHARED_LIBRARY ON CACHE BOOL "")
 
 set(LIBCXXABI_ENABLE_SHARED OFF CACHE BOOL "")
-set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
 set(LIBCXXABI_ENABLE_STATIC_UNWINDER ON CACHE BOOL "")
 set(LIBCXXABI_STATICALLY_LINK_UNWINDER_IN_STATIC_LIBRARY ON CACHE BOOL "")
 

libcxx/cmake/caches/Generic-msan.cmake

@@ -1 +1,2 @@
 set(LLVM_USE_SANITIZER "MemoryWithOrigins" CACHE STRING "")
+set(LIBCXXABI_USE_LLVM_UNWINDER OFF CACHE BOOL "") # MSAN is compiled against the system unwinder, which leads to false positives

libcxx/cmake/caches/Generic-tsan.cmake

@@ -1 +1,2 @@
 set(LLVM_USE_SANITIZER "Thread" CACHE STRING "")
+set(LIBCXXABI_USE_LLVM_UNWINDER OFF CACHE BOOL "") # TSAN is compiled against the system unwinder, which leads to false positives

libcxx/cmake/caches/MinGW.cmake

@@ -1,5 +1,4 @@
 set(LIBCXX_CXX_ABI libcxxabi CACHE STRING "")
-set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
 
 set(LIBCXXABI_ENABLE_SHARED OFF CACHE BOOL "")
 set(LIBCXX_ENABLE_STATIC_ABI_LIBRARY ON CACHE BOOL "")

libcxx/docs/BuildingLibcxx.rst

@@ -337,7 +337,7 @@ ABI Library Specific Options
 
 .. option:: LIBCXXABI_USE_LLVM_UNWINDER:BOOL
 
-  **Default**: ``OFF``
+  **Default**: ``ON``
 
   Build and use the LLVM unwinder. Note: This option can only be used when
   libc++abi is the C++ ABI library used.

libcxx/docs/ReleaseNotes/18.rst

@@ -191,3 +191,10 @@ Build System Changes
   passing ``-Dexecutor=...`` to ``llvm-lit``. Alternatively, this flag can be made persistent in the generated test
   configuration file by passing ``-DLIBCXX_TEST_PARAMS=executor=...``. This also applies to the ``LIBUWIND_EXECTOR``
   and ``LIBCXXABI_EXECUTOR`` CMake variables. LLVM 19 will completely remove support for the ``*_EXECUTOR`` variables.
+
+- ``LIBCXXABI_USE_LLVM_UNWINDER`` and ``COMPILER_RT_USE_LLVM_UNWINDER`` switched defaults from ``OFF`` to ``ON``.
+  This means that by default, libc++abi and compiler-rt will link against the LLVM provided ``libunwind`` library
+  instead of the system-provided unwinding library. If you are building the LLVM runtimes with the goal of shipping
+  them so that they can interoperate with other system-provided libraries that might be using a different unwinding
+  library (such as ``libgcc_s``), you should pass ``LIBCXXABI_USE_LLVM_UNWINDER=OFF`` and ``COMPILER_RT_USE_LLVM_UNWINDER=OFF``
+  to make sure the system-provided unwinding library is used by the LLVM runtimes.

libcxx/utils/ci/run-buildbot

@@ -439,11 +439,6 @@ generic-hardening-mode-debug)
     check-runtimes
     check-abi-list
 ;;
-generic-with_llvm_unwinder)
-    clean
-    generate-cmake -DLIBCXXABI_USE_LLVM_UNWINDER=ON
-    check-runtimes
-;;
 #
 # Module builds
 #

libcxxabi/CMakeLists.txt

@@ -46,7 +46,7 @@ option(LIBCXXABI_ENABLE_EXCEPTIONS
 option(LIBCXXABI_ENABLE_ASSERTIONS "Enable assertions independent of build mode." ON)
 option(LIBCXXABI_ENABLE_PEDANTIC "Compile with pedantic enabled." OFF)
 option(LIBCXXABI_ENABLE_WERROR "Fail and stop if a warning is triggered." OFF)
-option(LIBCXXABI_USE_LLVM_UNWINDER "Build and use the LLVM unwinder." OFF)
+option(LIBCXXABI_USE_LLVM_UNWINDER "Build and use the LLVM unwinder." ON)
 option(LIBCXXABI_ENABLE_STATIC_UNWINDER "Statically link the LLVM unwinder." OFF)
 option(LIBCXXABI_USE_COMPILER_RT "Use compiler-rt instead of libgcc" OFF)
 option(LIBCXXABI_ENABLE_THREADS "Build with threads enabled" ON)