build: introduce and use swift_target_link_search_directories

Introduce a swift_target_link_search_directories which allows you to
append a search path to the linker.  This interface also allows a tweak
to make the library search directory addition more portable across
compilers (e.g. cl vs clang).

Author: compnerd

cmake/modules/AddSwift.cmake

@@ -294,7 +294,7 @@ endfunction()
 function(_add_variant_link_flags)
   set(oneValueArgs SDK ARCH BUILD_TYPE ENABLE_ASSERTIONS ANALYZE_CODE_COVERAGE
   DEPLOYMENT_VERSION_OSX DEPLOYMENT_VERSION_IOS DEPLOYMENT_VERSION_TVOS DEPLOYMENT_VERSION_WATCHOS
-  RESULT_VAR_NAME ENABLE_LTO LTO_OBJECT_NAME)
+  RESULT_VAR_NAME ENABLE_LTO LTO_OBJECT_NAME LIBRARY_SEARCH_DIRECTORIES)
   cmake_parse_arguments(LFLAGS
     ""
     "${oneValueArgs}"
@@ -310,6 +310,7 @@ function(_add_variant_link_flags)
   endif()
 
   set(result ${${LFLAGS_RESULT_VAR_NAME}})
+  set(library_search_directories ${${LFLAGS_LIBRARY_SEARCH_DIRECTORIES}})
 
   _add_variant_c_compile_link_flags(
     SDK "${LFLAGS_SDK}"
@@ -337,8 +338,9 @@ function(_add_variant_link_flags)
   elseif("${LFLAGS_SDK}" STREQUAL "ANDROID")
     list(APPEND result
         "-ldl"
-        "-L${SWIFT_ANDROID_PREBUILT_PATH}/lib/gcc/arm-linux-androideabi/${SWIFT_ANDROID_NDK_GCC_VERSION}.x"
         "${SWIFT_ANDROID_NDK_PATH}/sources/cxx-stl/llvm-libc++/libs/armeabi-v7a/libc++_shared.so")
+    list(APPEND library_search_directories
+        "${SWIFT_ANDROID_PREBUILT_PATH}/lib/gcc/arm-linux-androideabi/${SWIFT_ANDROID_NDK_GCC_VERSION}.x")
   else()
     list(APPEND result "-lobjc")
 
@@ -357,13 +359,14 @@ function(_add_variant_link_flags)
   endif()
 
   if(NOT "${SWIFT_${LFLAGS_SDK}_ICU_UC}" STREQUAL "")
-    list(APPEND result "-L${SWIFT_${sdk}_ICU_UC}")
+    list(APPEND library_search_directories "${SWIFT_${sdk}_ICU_UC}")
   endif()
   if(NOT "${SWIFT_${LFLAGS_SDK}_ICU_I18N}" STREQUAL "")
-    list(APPEND result "-L${SWIFT_${sdk}_ICU_I18N}")
+    list(APPEND library_search_directories "${SWIFT_${sdk}_ICU_I18N}")
   endif()
 
   set("${LFLAGS_RESULT_VAR_NAME}" "${result}" PARENT_SCOPE)
+  set("${LFLAGS_LIBRARY_SEARCH_DIRECTORIES}" "${library_search_directories}" PARENT_SCOPE)
 endfunction()
 
 # Look up extra flags for a module that matches a regexp.
@@ -460,6 +463,14 @@ function(_add_swift_lipo_target)
   endif()
 endfunction()
 
+function(swift_target_link_search_directories target directories)
+  set(STLD_FLAGS "")
+  foreach(directory ${directories})
+    set(STLD_FLAGS " ${CMAKE_LIBRARY_PATH_FLAG}${directory}")
+  endforeach()
+  set_property(TARGET ${target} APPEND_STRING PROPERTY LINK_FLAGS ${STLD_FLAGS})
+endfunction()
+
 # Add a single variant of a new Swift library.
 #
 # Usage:
@@ -988,6 +999,10 @@ function(_add_swift_library_single target name)
   # Don't set PROPERTY COMPILE_FLAGS or LINK_FLAGS directly.
   set(c_compile_flags ${SWIFTLIB_SINGLE_C_COMPILE_FLAGS})
   set(link_flags ${SWIFTLIB_SINGLE_LINK_FLAGS})
+  set(library_search_directories
+      "${SWIFTLIB_DIR}/${SWIFTLIB_SINGLE_SUBDIR}"
+      "${SWIFT_NATIVE_SWIFT_TOOLS_PATH}/../lib/swift/${SWIFTLIB_SINGLE_SUBDIR}"
+      "${SWIFT_NATIVE_SWIFT_TOOLS_PATH}/../lib/swift/${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_LIB_SUBDIR}")
 
   # Add variant-specific flags.
   if(SWIFTLIB_SINGLE_TARGET_LIBRARY)
@@ -1029,6 +1044,7 @@ function(_add_swift_library_single target name)
     DEPLOYMENT_VERSION_TVOS "${SWIFTLIB_DEPLOYMENT_VERSION_TVOS}"
     DEPLOYMENT_VERSION_WATCHOS "${SWIFTLIB_DEPLOYMENT_VERSION_WATCHOS}"
     RESULT_VAR_NAME link_flags
+    LIBRARY_SEARCH_DIRECTORIES library_search_directories
       )
 
   if(SWIFT_ENABLE_GOLD_LINKER AND
@@ -1081,7 +1097,8 @@ function(_add_swift_library_single target name)
   set_property(TARGET "${target}" APPEND_STRING PROPERTY
       COMPILE_FLAGS " ${c_compile_flags}")
   set_property(TARGET "${target}" APPEND_STRING PROPERTY
-    LINK_FLAGS " ${link_flags} -L${SWIFTLIB_DIR}/${SWIFTLIB_SINGLE_SUBDIR} -L${SWIFT_NATIVE_SWIFT_TOOLS_PATH}/../lib/swift/${SWIFTLIB_SINGLE_SUBDIR} -L${SWIFT_NATIVE_SWIFT_TOOLS_PATH}/../lib/swift/${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_LIB_SUBDIR}")
+      LINK_FLAGS " ${link_flags}")
+  swift_target_link_search_directories(${target} ${library_search_directories})
 
   # Adjust the linked libraries for windows targets.  On Windows, the link is
   # performed against the import library, and the runtime uses the dll.  Not
@@ -1133,8 +1150,12 @@ function(_add_swift_library_single target name)
   if(target_static)
     set_property(TARGET "${target_static}" APPEND_STRING PROPERTY
         COMPILE_FLAGS " ${c_compile_flags}")
-    set_property(TARGET "${target_static}" APPEND_STRING PROPERTY
-      LINK_FLAGS " ${link_flags} -L${SWIFTSTATICLIB_DIR}/${SWIFTLIB_SINGLE_SUBDIR} -L${SWIFT_NATIVE_SWIFT_TOOLS_PATH}/../lib/swift/${SWIFTLIB_SINGLE_SUBDIR} -L${SWIFT_NATIVE_SWIFT_TOOLS_PATH}/../lib/swift/${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_LIB_SUBDIR}")
+    set(library_search_directories
+        "${SWIFTSTATICLIB_DIR}/${SWIFTLIB_SINGLE_SUBDIR}"
+        "${SWIFT_NATIVE_SWIFT_TOOLS_PATH}/../lib/swift/${SWIFTLIB_SINGLE_SUBDIR}"
+        "${SWIFT_NATIVE_SWIFT_TOOLS_PATH}/../lib/swift/${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_LIB_SUBDIR}")
+    swift_target_link_search_directories(${target_static}
+      ${library_search_directories})
     target_link_libraries("${target_static}" PRIVATE
         ${SWIFTLIB_SINGLE_PRIVATE_LINK_LIBRARIES})
   endif()
@@ -1773,9 +1794,6 @@ function(_add_swift_executable_single name)
     ANALYZE_CODE_COVERAGE "${SWIFT_ANALYZE_CODE_COVERAGE}"
     RESULT_VAR_NAME link_flags)
 
-  list(APPEND link_flags
-      "-L${SWIFTLIB_DIR}/${SWIFT_SDK_${SWIFTEXE_SINGLE_SDK}_LIB_SUBDIR}")
-
   if(SWIFTEXE_SINGLE_DISABLE_ASLR)
     list(APPEND link_flags "-Wl,-no_pie")
   endif()
@@ -1839,6 +1857,8 @@ function(_add_swift_executable_single name)
 
   set_property(TARGET ${name} APPEND_STRING PROPERTY
       COMPILE_FLAGS " ${c_compile_flags}")
+  swift_target_link_search_directories(${name}
+      "${SWIFTLIB_DIR}/${SWIFT_SDK_${SWIFTEXE_SINGLE_SDK}_LIB_SUBDIR}")
   set_property(TARGET ${name} APPEND_STRING PROPERTY
       LINK_FLAGS " ${link_flags}")
   if (SWIFT_PARALLEL_LINK_JOBS)