Re-add EXTRA_RPATHS CMake logic.

This logic is used for the TensorFlow module.
It was somehow lost in the merge.
I marked all additions within SWIFT_ENABLE_TENSORFLOW comments.

Author: dan-zheng

cmake/modules/AddSwift.cmake

@@ -593,6 +593,9 @@ endfunction()
 #     [LINK_FLAGS flag1...]
 #     [API_NOTES_NON_OVERLAY]
 #     [FILE_DEPENDS target1 ...]
+# SWIFT_ENABLE_TENSORFLOW
+#     [EXTRA_RPATHS rpath1 ...]
+# END SWIFT_ENABLE_TENSORFLOW
 #     [DONT_EMBED_BITCODE]
 #     [IS_STDLIB]
 #     [FORCE_BUILD_OPTIMIZED]
@@ -652,6 +655,11 @@ endfunction()
 # FILE_DEPENDS
 #   Additional files this library depends on.
 #
+# SWIFT_ENABLE_TENSORFLOW
+# EXTRA_RPATHS
+#   List of directories to add to this library's RPATH.
+# END SWIFT_ENABLE_TENSORFLOW
+#
 # DONT_EMBED_BITCODE
 #   Don't embed LLVM bitcode in this target, even if it is enabled globally.
 #
@@ -695,6 +703,9 @@ function(_add_swift_library_single target name)
         C_COMPILE_FLAGS
         DEPENDS
         FILE_DEPENDS
+        # SWIFT_ENABLE_TENSORFLOW
+        EXTRA_RPATHS
+        # END SWIFT_ENABLE_TENSORFLOW
         FRAMEWORK_DEPENDS
         FRAMEWORK_DEPENDS_WEAK
         INCORPORATE_OBJECT_LIBRARIES
@@ -1031,6 +1042,28 @@ function(_add_swift_library_single target name)
       INSTALL_RPATH "$ORIGIN:/usr/lib/swift/cygwin")
   endif()
 
+  # SWIFT_ENABLE_TENSORFLOW
+  # Hande extra RPATHs.
+  set(local_rpath "")
+  if("${SWIFTLIB_SINGLE_SDK}" STREQUAL "LINUX" AND NOT "${SWIFTLIB_SINGLE_SDK}" STREQUAL "ANDROID")
+    set(local_rpath "$ORIGIN:/usr/lib/swift/linux")
+  elseif("${SWIFTLIB_SINGLE_SDK}" STREQUAL "CYGWIN")
+    set(local_rpath "$ORIGIN:/usr/lib/swift/cygwin")
+  endif()
+  foreach(rpath_element ${SWIFTLIB_SINGLE_EXTRA_RPATHS})
+    if("${local_rpath}" STREQUAL "")
+      set(local_rpath "${rpath_element}")
+    else()
+      set(local_rpath "${local_rpath}:${rpath_element}")
+    endif()
+  endforeach()
+  if(NOT "${local_rpath}" STREQUAL "")
+    set_target_properties("${target}"
+      PROPERTIES
+      INSTALL_RPATH "${local_rpath}")
+  endif()
+  # END SWIFT_ENABLE_TENSORFLOW
+
   set_target_properties("${target}" PROPERTIES BUILD_WITH_INSTALL_RPATH YES)
   set_target_properties("${target}" PROPERTIES FOLDER "Swift libraries")
 
@@ -2131,6 +2164,20 @@ function(_add_swift_executable_single name)
         "-Xlinker" "@executable_path/../lib/swift/${SWIFT_SDK_${SWIFTEXE_SINGLE_SDK}_LIB_SUBDIR}")
   endif()
 
+  # SWIFT_ENABLE_TENSORFLOW
+  set(swift_relative_library_path "../lib/swift/${SWIFT_SDK_${SWIFTEXE_SINGLE_SDK}_LIB_SUBDIR}")
+  is_darwin_based_sdk("${SWIFTEXE_SINGLE_SDK}" IS_DARWIN)
+  # NOTE: Adding "${SWIFTLIB_DIR}/linux" to the rpath is a hack solely for
+  # working around tests like Driver/linker.swift which copy/hard link Swift
+  # executables to different directories without also copying the "libs"
+  # directory. A more robust solution should be found.
+  if("${SWIFTEXE_SINGLE_SDK}" STREQUAL "LINUX" AND NOT "${SWIFTEXE_SINGLE_SDK}" STREQUAL "ANDROID")
+    set(local_rpath "$ORIGIN:$ORIGIN/${swift_relative_library_path}:${SWIFTLIB_DIR}/linux:/usr/lib/swift/linux")
+  elseif("${SWIFTEXE_SINGLE_SDK}" STREQUAL "CYGWIN")
+    set(local_rpath "$ORIGIN:$ORIGIN/${swift_relative_library_path}:${SWIFTLIB_DIR}/cygwin:/usr/lib/swift/cygwin")
+  endif()
+  # END SWIFT_ENABLE_TENSORFLOW
+
   # Find the names of dependency library targets.
   #
   # We don't add the ${ARCH} to the target suffix because we want to link
@@ -2192,6 +2239,13 @@ function(_add_swift_executable_single name)
 
   set_target_properties(${name}
       PROPERTIES FOLDER "Swift executables")
+
+  # SWIFT_ENABLE_TENSORFLOW
+  if(NOT "${local_rpath}" STREQUAL "")
+    set_target_properties("${name}" PROPERTIES INSTALL_RPATH "${local_rpath}")
+  endif()
+  set_target_properties("${name}" PROPERTIES BUILD_WITH_INSTALL_RPATH YES)
+  # END SWIFT_ENABLE_TENSORFLOW
 endfunction()
 
 # Add an executable for each target variant. Executables are given suffixes

stdlib/public/TensorFlow/CMakeLists.txt

@@ -87,4 +87,4 @@ add_swift_target_library(swiftTensorFlow ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_
   SWIFT_COMPILE_FLAGS "${swift_stdlib_compile_flags}"
   LINK_FLAGS "${SWIFT_RUNTIME_SWIFT_LINK_FLAGS}"
   INSTALL_IN_COMPONENT stdlib
-  EXTRA_RPATH "${SWIFT_TENSORFLOW_TARGET_LIB_DIR}")
+  EXTRA_RPATHS "${SWIFT_TENSORFLOW_TARGET_LIB_DIR}")