From c6da90bd39f3e03ba6a2a4cfac0d179e04e0b236 Mon Sep 17 00:00:00 2001 From: Brad King Date: Mon, 28 Feb 2022 12:53:15 -0500 Subject: FindThreads: Revert "Honor THREADS_PREFER_PTHREAD_FLAG when ... in libc" Revert commit 5efb6fb516 (FindThreads: Honor THREADS_PREFER_PTHREAD_FLAG when pthread is found in libc, 2021-11-03, v3.21.5~4^2). The check for the `-pthread` flag can pass on compilers like XL, that interprets it as `-p -t hread` and returns zero. Prior to that commit, we did not use the check in the `CMAKE_HAVE_LIBC_PTHREAD` code path. Now we do, it succeeds, and we incorrectly add the `-pthread` flag for XL. This change was backported to the 3.21 and 3.22 release series long after they initially came out. Since there may be more cases where we now add `-pthread` incorrectly, it is simplest to revert the change in all release series pending further investigation. Fixes: #23270 --- Modules/FindThreads.cmake | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) diff --git a/Modules/FindThreads.cmake b/Modules/FindThreads.cmake index ffd3352..c6a3451 100644 --- a/Modules/FindThreads.cmake +++ b/Modules/FindThreads.cmake @@ -164,21 +164,18 @@ if(CMAKE_HAVE_PTHREAD_H) elseif(CMAKE_CXX_COMPILER_LOADED) CHECK_CXX_SOURCE_COMPILES("${PTHREAD_C_CXX_TEST_SOURCE}" CMAKE_HAVE_LIBC_PTHREAD) endif() - - # Check for -pthread first if enabled. This is the recommended - # way, but not backwards compatible as one must also pass -pthread - # as compiler flag then. - if(THREADS_PREFER_PTHREAD_FLAG) - _check_pthreads_flag() - endif() - - if(Threads_FOUND) - # do nothing, we are done - elseif(CMAKE_HAVE_LIBC_PTHREAD) + if(CMAKE_HAVE_LIBC_PTHREAD) set(CMAKE_THREAD_LIBS_INIT "") set(CMAKE_HAVE_THREADS_LIBRARY 1) set(Threads_FOUND TRUE) else() + # Check for -pthread first if enabled. This is the recommended + # way, but not backwards compatible as one must also pass -pthread + # as compiler flag then. + if (THREADS_PREFER_PTHREAD_FLAG) + _check_pthreads_flag() + endif () + if(CMAKE_SYSTEM MATCHES "GHS-MULTI") _check_threads_lib(posix pthread_create CMAKE_HAVE_PTHREADS_CREATE) endif() -- cgit v0.12