Fixes and updates for CMake build system

A number of small fixes and updates to enable
libdispatch's CMake-based build system to be
invoked from Swift's utils/build-script.
 + removed libpwq support and added internal_workqueue
 + added dtrace rule to generate provider.h
 + build shared libraries by default
 + enable using gold linker by default
 + fixes for building tests with Swift enabled
 + symlink src/. to src/.libs for compatibility with
   autoconf-based builds (avoids need for tightly
   coupled changes across multiple Swift repositories
   which expect to find src/.libs/libdispatch.so).
 + Increase test timeout to 600 seconds to reduce risk of
   spurious failures when run under Swift CI.

Author: dgrove-oss

CMakeLists.txt

@@ -16,45 +16,32 @@ set(THREADS_PREFER_PTHREAD_FLAG TRUE)
 find_package(Threads REQUIRED)
 
 include(GNUInstallDirs)
-include(ExternalProject)
 
 set(WITH_BLOCKS_RUNTIME "" CACHE PATH "Path to blocks runtime")
-set(WITH_PTHREAD_WORKQUEUES "" CACHE PATH "Path to pthread-workqueues")
 
 include(DispatchAppleOptions)
 
 option(ENABLE_DISPATCH_INIT_CONSTRUCTOR "enable libdispatch_init as a constructor" ON)
 set(USE_LIBDISPATCH_INIT_CONSTRUCTOR ${ENABLE_DISPATCH_INIT_CONSTRUCTOR})
 
-# TODO(compnerd) swift options
+option(BUILD_SHARED_LIBS "build shared libraries" ON)
+
+option(USE_GOLD_LINKER "use the gold linker" ON)
 
-# TODO(compnerd) consider adding a flag for USE_GOLD_LINKER.  Currently, we
-# expect the user to specify `-fuse-ld=gold`
+# TODO(compnerd) swift options
 
 option(ENABLE_THREAD_LOCAL_STORAGE "enable usage of thread local storage via __thread" ON)
 set(DISPATCH_USE_THREAD_LOCAL_STORAGE ${ENABLE_THREAD_LOCAL_STORAGE})
 
-if(EXISTS "${CMAKE_SOURCE_DIR}/libpwq/CMakeLists.txt")
-  ExternalProject_Add(pwq
-                      SOURCE_DIR
-                        "${CMAKE_SOURCE_DIR}/libpwq"
-                      CMAKE_ARGS
-                        -DCMAKE_INSTALL_PREFIX=<INSTALL_DIR>
-                        -DCMAKE_INSTALL_LIBDIR=${CMAKE_INSTALL_LIBDIR}
-                        -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}
-                      BUILD_BYPRODUCTS
-                        <INSTALL_DIR>/${CMAKE_INSTALL_LIBDIR}/${CMAKE_STATIC_LIBRARY_PREFIX}pthread_workqueue${CMAKE_STATIC_LIBRARY_SUFFIX})
-  ExternalProject_Get_Property(pwq install_dir)
-  add_library(PTHREAD::workqueue UNKNOWN IMPORTED)
-  set_target_properties(PTHREAD::workqueue
-                        PROPERTIES
-                          IMPORTED_LOCATION ${install_dir}/${CMAKE_INSTALL_LIBDIR}/${CMAKE_STATIC_LIBRARY_PREFIX}pthread_workqueue${CMAKE_STATIC_LIBRARY_SUFFIX})
-  set(WITH_PTHREAD_WORKQUEUES "${install_dir}" CACHE PATH "Path to pthread-workqueues" FORCE)
-  set(HAVE_PTHREAD_WORKQUEUES 1)
+# TODO: Real CMake logic for internal workqueues
+if(CMAKE_SYSTEM_NAME STREQUAL Linux OR
+   CMAKE_SYSTEM_NAME STREQUAL Android OR
+   CMAKE_SYSTEM_NAME STREQUAL Windows)
+ set(DISPATCH_USE_INTERNAL_WORKQUEUE 1)
+ set(HAVE_PTHREAD_WORKQUEUES 0)
 else()
-  # TODO(compnerd) support system installed pthread-workqueues
-  # find_package(pthread_workqueues REQUIRED)
-  # set(HAVE_PTHREAD_WORKQUEUES 1)
+ set(DISPATCH_USE_INTERNAL_WORKQUEUE 0)
+ set(HAVE_PTHREAD_WORKQUEUES 1)
 endif()
 
 if(CMAKE_SYSTEM_NAME STREQUAL Linux OR
@@ -179,12 +166,13 @@ check_symbol_exists(VQ_VERYLOWDISK "sys/mount.h" HAVE_DECL_VQ_VERYLOWDISK)
 
 check_symbol_exists(program_invocation_name "errno.h" HAVE_DECL_PROGRAM_INVOCATION_SHORT_NAME)
 
-find_program(dtrace_EXECUTABLE dtrace)
-if(dtrace_EXECUTABLE)
+find_program(DTRACE dtrace)
+if(DTRACE)
   add_definitions(-DDISPATCH_USE_DTRACE=1)
 else()
   add_definitions(-DDISPATCH_USE_DTRACE=0)
 endif()
+include(DTrace)
 
 find_program(leaks_EXECUTABLE leaks)
 if(leaks_EXECUTABLE)

cmake/config.h.in

@@ -1,6 +1,5 @@
-
-/* Define if building pthread work queues from source */
-#cmakedefine BUILD_OWN_PTHREAD_WORKQUEUES
+/* Use libdispatch's own implementation of pthread workqueues */
+#cmakedefine01 DISPATCH_USE_INTERNAL_WORKQUEUE
 
 /* Enable usage of thread local storage via __thread */
 #cmakedefine01 DISPATCH_USE_THREAD_LOCAL_STORAGE

cmake/modules/DTrace.cmake

@@ -0,0 +1,10 @@
+MACRO (DTRACE_HEADER provider header)
+  if (DTRACE)
+    ADD_CUSTOM_COMMAND(
+      OUTPUT  ${header}
+      COMMAND ${DTRACE} -h -s ${provider} -o ${header}
+      DEPENDS ${provider}
+    )
+  ENDIF()
+ENDMACRO()
+

src/CMakeLists.txt

@@ -1,10 +1,17 @@
 
 include(SwiftSupport)
 
+set(dispatch_DTRACE_HEADERS)
+if(DTRACE)
+  list(APPEND dispatch_DTRACE_HEADERS ${CMAKE_CURRENT_BINARY_DIR}/provider.h)
+endif()
+DTRACE_HEADER(${CMAKE_CURRENT_SOURCE_DIR}/provider.d ${CMAKE_CURRENT_BINARY_DIR}/provider.h)
+
 set(dispatch_BLOCK_SOURCES block.cpp)
 if(HAVE_OBJC)
   list(APPEND dispatch_BLOCK_SOURCES data.m object.m)
 endif()
+
 set(dispatch_SWIFT_SOURCES)
 if(CMAKE_SWIFT_COMPILER)
   set(swift_optimization_flags)
@@ -39,7 +46,9 @@ if(CMAKE_SWIFT_COMPILER)
   list(APPEND dispatch_SWIFT_SOURCES
        swift/DispatchStubs.cc;${CMAKE_CURRENT_BINARY_DIR}/swiftDispatch.o)
 endif()
+
 add_library(dispatch
+              ${dispatch_DTRACE_HEADERS}
               allocator.c
               apply.c
               benchmark.c
@@ -77,6 +86,8 @@ add_library(dispatch
               event/event_epoll.c
               event/event_internal.h
               event/event_kevent.c
+              event/workqueue_internal.h
+              event/workqueue.c
               firehose/firehose_internal.h
               shims/android_stubs.h
               shims/atomic.h
@@ -93,12 +104,24 @@ add_library(dispatch
               shims/yield.h
               ${dispatch_BLOCK_SOURCES}
               ${dispatch_SWIFT_SOURCES})
+# Temporary staging; the various swift projects that depend on libdispatch
+# all expect libdispatch.so to be in src/.libs/libdispatch.so
+# So make a symlink so we don't have to do a coordinated commit across all the
+# swift projects to change this assumption.
+add_custom_target(.libs ALL
+                  COMMAND cmake -E create_symlink . .libs)
 target_include_directories(dispatch
                            PRIVATE
                              ${CMAKE_BINARY_DIR}
+                             ${CMAKE_CURRENT_BINARY_DIR}
                              ${CMAKE_SOURCE_DIR}
                              ${CMAKE_CURRENT_SOURCE_DIR}
                              ${CMAKE_SOURCE_DIR}/private)
+if (USE_GOLD_LINKER)
+  target_link_libraries(dispatch
+	                    PRIVATE
+	                    -fuse-ld=gold)
+endif()
 if(WITH_PTHREAD_WORKQUEUES)
   target_include_directories(dispatch
                              SYSTEM BEFORE PRIVATE

tests/CMakeLists.txt

@@ -38,6 +38,9 @@ if(BSD_OVERLAY_FOUND)
                         PRIVATE
                           ${BSD_OVERLAY_LDFLAGS})
 endif()
+if(CMAKE_SWIFT_RUNTIME_LIBDIR)
+  target_link_libraries(bsdtestharness PRIVATE -L${CMAKE_SWIFT_RUNTIME_LIBDIR} -lswiftCore -lswiftSwiftOnoneSupport -Wl,-rpath -Wl,${CMAKE_SWIFT_RUNTIME_LIBDIR})
+endif()
 
 function(add_unit_test name)
   set(options DISABLED_TEST)
@@ -86,11 +89,14 @@ function(add_unit_test name)
                             ${BSD_OVERLAY_LDFLAGS})
   endif()
   target_link_libraries(${name} PRIVATE bsdtests)
+  if(CMAKE_SWIFT_RUNTIME_LIBDIR)
+	target_link_libraries(${name} PRIVATE -L${CMAKE_SWIFT_RUNTIME_LIBDIR} -lswiftCore -lswiftSwiftOnoneSupport -Wl,-rpath -Wl,${CMAKE_SWIFT_RUNTIME_LIBDIR})
+  endif()
   add_test(NAME ${name}
            COMMAND bsdtestharness $<TARGET_FILE:${name}>)
   set_tests_properties(${name}
                        PROPERTIES
-                         TIMEOUT 30
+                         TIMEOUT 600
                          DEPENDS bsdtestharness
                          WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
   if(NOT leaks_EXECUTABLE)