[arrow] branch master updated: ARROW-4330: [C++] More robust discovery of pthreads

[uw...@apache.org]

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uwe pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/arrow.git


The following commit(s) were added to refs/heads/master by this push:
     new b427864  ARROW-4330: [C++] More robust discovery of pthreads
b427864 is described below

commit b4278641a6a56c56d2007469b0eb840d52cc007d
Author: Wes McKinney <we...@apache.org>
AuthorDate: Sun Jan 27 21:38:37 2019 +0100

    ARROW-4330: [C++] More robust discovery of pthreads
    
    I found when using a non-system gcc (e.g. the `gcc_linux-64` and `gxx_linux-64` gcc7 conda packages) that CMake is not able to discover pthreads. The conda-forge community regards this as a bug in CMake, but there is another better way to do this using the built-in `FindThreads.cmake`.
    
    There's a chance this might also resolve the missing thread symbol in the Gandiva windows build, but I haven't tried it yet
    
    Author: Wes McKinney <we...@apache.org>
    
    Closes #3494 from wesm/pthreads-cmake and squashes the following commits:
    
    828d6bf1 <Wes McKinney> Code review
    38349ad8 <Wes McKinney> Restore jemalloc dependencies on pthreads
    122e2647 <Wes McKinney> Clean up system link libraries for pthread, librt
    7522a60a <Wes McKinney> Use FindThreads.cmake to handle -pthread
---
 cpp/CMakeLists.txt                          | 52 +++++++++--------------------
 cpp/cmake_modules/ThirdpartyToolchain.cmake | 14 +++-----
 2 files changed, 19 insertions(+), 47 deletions(-)

diff --git a/cpp/CMakeLists.txt b/cpp/CMakeLists.txt
index 5309c35..3ec430e 100644
--- a/cpp/CMakeLists.txt
+++ b/cpp/CMakeLists.txt
@@ -839,50 +839,28 @@ if (ARROW_BUILD_BENCHMARKS)
     ${ARROW_TEST_LINK_LIBS})
 endif()
 
+set(ARROW_SYSTEM_LINK_LIBS)
+
 if (ARROW_JEMALLOC)
   add_definitions(-DARROW_JEMALLOC)
   add_definitions(-DARROW_JEMALLOC_INCLUDE_DIR=${JEMALLOC_INCLUDE_DIR})
-
-  if (NOT WIN32 AND NOT APPLE)
-    set(ARROW_JEMALLOC_LINK_LIBS
-      jemalloc_static
-      # For glibc <2.17 we need to link to librt.
-      # As we compile with --as-needed by default, the linker will omit this
-      # dependency if not required.
-      rt
-      )
-  else()
-    set(ARROW_JEMALLOC_LINK_LIBS
-      jemalloc_static
-      )
-  endif()
-  list(APPEND
-    ARROW_SHARED_PRIVATE_LINK_LIBS
-    ${ARROW_JEMALLOC_LINK_LIBS})
-  list(APPEND
-    ARROW_STATIC_LINK_LIBS
-    ${ARROW_JEMALLOC_LINK_LIBS})
-  list(APPEND
-    ARROW_STATIC_INSTALL_INTERFACE_LIBS
-    jemalloc
-    rt)
+  list(APPEND ARROW_SYSTEM_LINK_LIBS jemalloc_static)
 endif(ARROW_JEMALLOC)
 
-if (PTHREAD_LIBRARY)
-  list(APPEND
-    ARROW_LINK_LIBS
-    pthreadshared)
-  list(APPEND
-    ARROW_SHARED_INSTALL_INTERFACE_LIBS
-    pthread)
-  list(APPEND
-    ARROW_STATIC_LINK_LIBS
-    pthreadshared)
-  list(APPEND
-    ARROW_STATIC_INSTALL_INTERFACE_LIBS
-    pthread)
+if (THREADS_FOUND)
+  list(APPEND ARROW_SYSTEM_LINK_LIBS Threads::Threads)
 endif()
 
+if (NOT WIN32 AND NOT APPLE)
+  # Pass -lrt on Linux only
+  list(APPEND ARROW_SYSTEM_LINK_LIBS rt)
+endif()
+
+list(APPEND ARROW_LINK_LIBS ${ARROW_SYSTEM_LINK_LIBS})
+list(APPEND ARROW_STATIC_LINK_LIBS ${ARROW_SYSTEM_LINK_LIBS})
+list(APPEND ARROW_SHARED_INSTALL_INTERFACE_LIBS ${ARROW_SYSTEM_LINK_LIBS})
+list(APPEND ARROW_STATIC_INSTALL_INTERFACE_LIBS ${ARROW_SYSTEM_LINK_LIBS})
+
 ############################################################
 # Subdirectories
 ############################################################
diff --git a/cpp/cmake_modules/ThirdpartyToolchain.cmake b/cpp/cmake_modules/ThirdpartyToolchain.cmake
index 5a75a9b..13a6a47 100644
--- a/cpp/cmake_modules/ThirdpartyToolchain.cmake
+++ b/cpp/cmake_modules/ThirdpartyToolchain.cmake
@@ -334,14 +334,8 @@ endif()
 # ----------------------------------------------------------------------
 # Find pthreads
 
-if (WIN32)
-  set(PTHREAD_LIBRARY "PTHREAD_LIBRARY-NOTFOUND")
-else()
-  find_library(PTHREAD_LIBRARY pthread)
-  message(STATUS "Found pthread: ${PTHREAD_LIBRARY}")
-  add_library(pthreadshared SHARED IMPORTED)
-  set_target_properties(pthreadshared PROPERTIES IMPORTED_LOCATION ${PTHREAD_LIBRARY})
-endif()
+set(THREADS_PREFER_PTHREAD_FLAG ON)
+find_package(Threads REQUIRED)
 
 # ----------------------------------------------------------------------
 # Add Boost dependencies (code adapted from Apache Kudu (incubating))
@@ -802,7 +796,7 @@ if (ARROW_JEMALLOC)
   ADD_THIRDPARTY_LIB(jemalloc
     STATIC_LIB ${JEMALLOC_STATIC_LIB}
     SHARED_LIB ${JEMALLOC_SHARED_LIB}
-    DEPS ${PTHREAD_LIBRARY})
+    DEPS Threads::Threads)
   add_dependencies(jemalloc_static jemalloc_ep)
 endif()
 
@@ -1532,7 +1526,7 @@ if (ARROW_USE_GLOG)
     set(GLOG_STATIC_LIB "${GLOG_BUILD_DIR}/lib/${CMAKE_STATIC_LIBRARY_PREFIX}glog${CMAKE_STATIC_LIBRARY_SUFFIX}")
     set(GLOG_CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fPIC")
     set(GLOG_CMAKE_C_FLAGS "${EP_C_FLAGS} -fPIC")
-    if (PTHREAD_LIBRARY)
+    if (Threads::Threads)
       set(GLOG_CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fPIC -pthread")
       set(GLOG_CMAKE_C_FLAGS "${EP_C_FLAGS} -fPIC -pthread")
     endif()