Imported Upstream version 3.15.0upstream/3.15.0

1 files changed, 38 insertions, 6 deletions

diff --git a/Modules/FindThreads.cmake b/Modules/FindThreads.cmake
index 36b55c274..b0c91b2ac 100644
--- a/Modules/FindThreads.cmake
+++ b/Modules/FindThreads.cmake
@@ -35,19 +35,42 @@ recommended for new code.
 #]=======================================================================]
 
 include (CheckLibraryExists)
-include (CheckSymbolExists)
 set(Threads_FOUND FALSE)
 set(CMAKE_REQUIRED_QUIET_SAVE ${CMAKE_REQUIRED_QUIET})
 set(CMAKE_REQUIRED_QUIET ${Threads_FIND_QUIETLY})
 
 if(CMAKE_C_COMPILER_LOADED)
   include (CheckIncludeFile)
+  include (CheckCSourceCompiles)
 elseif(CMAKE_CXX_COMPILER_LOADED)
   include (CheckIncludeFileCXX)
+  include (CheckCXXSourceCompiles)
 else()
   message(FATAL_ERROR "FindThreads only works if either C or CXX language is enabled")
 endif()
 
+# simple pthread test code
+set(PTHREAD_C_CXX_TEST_SOURCE [====[
+#include <pthread.h>
+
+void* test_func(void* data)
+{
+  return data;
+}
+
+int main(void)
+{
+  pthread_t thread;
+  pthread_create(&thread, NULL, test_func, NULL);
+  pthread_detach(thread);
+  pthread_join(thread, NULL);
+  pthread_atfork(NULL, NULL, NULL);
+  pthread_exit(NULL);
+
+  return 0;
+}
+]====])
+
 # Internal helper macro.
 # Do NOT even think about using it outside of this file!
 macro(_check_threads_lib LIBNAME FUNCNAME VARNAME)
@@ -106,8 +129,8 @@ if(CMAKE_C_COMPILER_LOADED)
 else()
   CHECK_INCLUDE_FILE_CXX("pthread.h" CMAKE_HAVE_PTHREAD_H)
 endif()
-if(CMAKE_HAVE_PTHREAD_H)
 
+if(CMAKE_HAVE_PTHREAD_H)
   #
   # We have pthread.h
   # Let's check for the library now.
@@ -115,13 +138,19 @@ if(CMAKE_HAVE_PTHREAD_H)
   set(CMAKE_HAVE_THREADS_LIBRARY)
   if(NOT THREADS_HAVE_PTHREAD_ARG)
     # Check if pthread functions are in normal C library.
-    CHECK_SYMBOL_EXISTS(pthread_create pthread.h CMAKE_HAVE_LIBC_CREATE)
-    if(CMAKE_HAVE_LIBC_CREATE)
+    # We list some pthread functions in PTHREAD_C_CXX_TEST_SOURCE test code.
+    # If the pthread functions already exist in C library, we could just use
+    # them instead of linking to the additional pthread library.
+    if(CMAKE_C_COMPILER_LOADED)
+      CHECK_C_SOURCE_COMPILES("${PTHREAD_C_CXX_TEST_SOURCE}" CMAKE_HAVE_LIBC_PTHREAD)
+    elseif(CMAKE_CXX_COMPILER_LOADED)
+      CHECK_CXX_SOURCE_COMPILES("${PTHREAD_C_CXX_TEST_SOURCE}" CMAKE_HAVE_LIBC_PTHREAD)
+    endif()
+    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.
@@ -129,6 +158,9 @@ if(CMAKE_HAVE_PTHREAD_H)
          _check_pthreads_flag()
       endif ()
 
+      if(CMAKE_SYSTEM MATCHES "GHS-MULTI")
+        _check_threads_lib(posix pthread_create CMAKE_HAVE_PTHREADS_CREATE)
+      endif()
       _check_threads_lib(pthreads pthread_create CMAKE_HAVE_PTHREADS_CREATE)
       _check_threads_lib(pthread  pthread_create CMAKE_HAVE_PTHREAD_CREATE)
       if(CMAKE_SYSTEM_NAME MATCHES "SunOS")
@@ -141,7 +173,7 @@ if(CMAKE_HAVE_PTHREAD_H)
   _check_pthreads_flag()
 endif()
 
-if(CMAKE_THREAD_LIBS_INIT OR CMAKE_HAVE_LIBC_CREATE)
+if(CMAKE_THREAD_LIBS_INIT OR CMAKE_HAVE_LIBC_PTHREAD)
   set(CMAKE_USE_PTHREADS_INIT 1)
   set(Threads_FOUND TRUE)
 endif()