dispatch: remove DispatchStubs on non-ObjC targets

This is no longer required. Address the long standing FIXME and simplify
the build.

Author: compnerd

Diff for: CMakeLists.txt

@@ -13,6 +13,8 @@ project(dispatch
   VERSION 1.3
   LANGUAGES C CXX)
 
+set(CMAKE_POSITION_INDEPENDENT_CODE YES)
+
 if("${CMAKE_C_SIMULATE_ID}" STREQUAL "MSVC")
   include(ClangClCompileRules)
 endif()

Diff for: dispatch/CMakeLists.txt

@@ -1,10 +1,8 @@
 
 if(CMAKE_SYSTEM_NAME STREQUAL Darwin)
   set(DISPATCH_MODULE_MAP ${PROJECT_SOURCE_DIR}/dispatch/darwin/module.modulemap)
-elseif(BUILD_SHARED_LIBS)
-  set(DISPATCH_MODULE_MAP ${PROJECT_SOURCE_DIR}/dispatch/generic/module.modulemap)
 else()
-  set(DISPATCH_MODULE_MAP ${PROJECT_SOURCE_DIR}/dispatch/generic_static/module.modulemap)
+  set(DISPATCH_MODULE_MAP ${PROJECT_SOURCE_DIR}/dispatch/generic/module.modulemap)
 endif()
 configure_file(dispatch-vfs.yaml.in
   ${CMAKE_BINARY_DIR}/dispatch-vfs-overlay.yaml

Diff for: dispatch/generic_static/module.modulemap

@@ -19,9 +19,6 @@ if(HAVE_OBJC AND CMAKE_DL_LIBS)
     ${CMAKE_DL_LIBS})
 endif()
 
-set_target_properties(BlocksRuntime PROPERTIES
-  POSITION_INDEPENDENT_CODE TRUE)
-
 if(LINKER_SUPPORTS_BUILD_ID)
   target_link_options(BlocksRuntime PRIVATE "LINKER:--build-id=sha1")
 endif()

Diff for: src/BlocksRuntime/CMakeLists.txt

@@ -82,19 +82,12 @@ if(ENABLE_DTRACE)
 endif()
 
 if(HAVE_OBJC)
-  # TODO(compnerd) split DispatchStubs.cc into a separate component for the ObjC
-  # registration and a separate component for the swift compiler's emission of a
-  # call to the ObjC autorelease elision entry point.
   target_sources(dispatch PRIVATE
     data.m
     object.m
-    swift/DispatchStubs.cc)
+    swift/DispatchStubs.m)
 endif()
 
-
-set_target_properties(dispatch PROPERTIES
-  POSITION_INDEPENDENT_CODE YES)
-
 target_include_directories(dispatch PUBLIC
   ${PROJECT_BINARY_DIR}
   ${PROJECT_SOURCE_DIR}

Diff for: src/CMakeLists.txt

@@ -1,9 +1,9 @@
-add_library(DispatchStubs STATIC
-  DispatchStubs.cc)
-target_include_directories(DispatchStubs PRIVATE
-  ${PROJECT_SOURCE_DIR})
-set_target_properties(DispatchStubs PROPERTIES
-  POSITION_INDEPENDENT_CODE YES)
+if(HAVE_OBJC)
+  add_library(DispatchStubs STATIC
+    DispatchStubs.m)
+  target_include_directories(DispatchStubs PRIVATE
+    ${PROJECT_SOURCE_DIR})
+endif()
 
 add_library(swiftDispatch
   Block.swift
@@ -27,10 +27,14 @@ set_target_properties(swiftDispatch PROPERTIES
   Swift_MODULE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/swift
   INTERFACE_INCLUDE_DIRECTORIES ${CMAKE_CURRENT_BINARY_DIR}/swift)
 target_link_libraries(swiftDispatch PRIVATE
-  DispatchStubs
+  $<$<BOOL:${HAVE_OBJC}>:DispatchStubs>
   BlocksRuntime::BlocksRuntime)
 target_link_libraries(swiftDispatch PUBLIC
   dispatch)
+if(NOT CMAKE_SYSTEM_NAME MATCHES "Darwin|Windows")
+  target_link_options(swiftDispatch PRIVATE "SHELL:-no-toolchain-stdlib-rpath")
+  set_target_properties(swiftDispatch PROPERTIES INSTALL_RPATH "$ORIGIN")
+endif()
 
 get_swift_host_arch(swift_arch)
 install(FILES
@@ -43,12 +47,9 @@ install(TARGETS swiftDispatch
   ARCHIVE DESTINATION ${INSTALL_TARGET_DIR}
   LIBRARY DESTINATION ${INSTALL_TARGET_DIR}
   RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
-if(NOT BUILD_SHARED_LIBS)
+if(HAVE_OBJC AND NOT BUILD_SHARED_LIBS)
   set_property(GLOBAL APPEND PROPERTY DISPATCH_EXPORTS DispatchStubs)
   install(TARGETS DispatchStubs
     EXPORT dispatchExports
     DESTINATION ${INSTALL_TARGET_DIR})
-elseif(NOT CMAKE_SYSTEM_NAME MATCHES "Darwin|Windows")
-  target_link_options(swiftDispatch PRIVATE "SHELL:-no-toolchain-stdlib-rpath")
-  set_target_properties(swiftDispatch PROPERTIES INSTALL_RPATH "$ORIGIN")
 endif()

Diff for: src/swift/CMakeLists.txt

@@ -11,13 +11,6 @@
 //===----------------------------------------------------------------------===//
 
 #include <dispatch/dispatch.h>
-#include <stdio.h>
-
-#if defined(__ELF__) || defined(__MACH__) || defined(__WASM__)
-#define DISPATCH_RUNTIME_STDLIB_INTERFACE __attribute__((__visibility__("default")))
-#else
-#define DISPATCH_RUNTIME_STDLIB_INTERFACE __declspec(dllexport)
-#endif
 
 #if USE_OBJC
 @protocol OS_dispatch_source;
@@ -34,11 +27,9 @@
 @protocol OS_dispatch_source_vnode;
 @protocol OS_dispatch_source_write;
 
-// #include <dispatch/private.h>
-__attribute__((constructor))
+__attribute__((__constructor__))
 static void _dispatch_overlay_constructor() {
-  Class source = objc_lookUpClass("OS_dispatch_source");
-  if (source) {
+  if (Class source = objc_lookUpClass("OS_dispatch_source")) {
     class_addProtocol(source, @protocol(OS_dispatch_source));
     class_addProtocol(source, @protocol(OS_dispatch_source_mach_send));
     class_addProtocol(source, @protocol(OS_dispatch_source_mach_recv));
@@ -54,5 +45,4 @@ static void _dispatch_overlay_constructor() {
     class_addProtocol(source, @protocol(OS_dispatch_source_write));
   }
 }
-
 #endif /* USE_OBJC */