Merge pull request #3210 from compnerd/experimental-linkers

Author: swift-ci

CMakeLists.txt

@@ -110,6 +110,10 @@ set(SWIFT_COMPILER_VERSION "" CACHE STRING
 set(CLANG_COMPILER_VERSION "" CACHE STRING
     "The internal version of the Clang compiler")
 
+# Indicate whether Swift should attempt to use the lld linker.
+set(SWIFT_ENABLE_LLD_LINKER FALSE CACHE BOOL
+    "Enable using the lld linker when available")
+
 # Indicate whether Swift should attempt to use the gold linker.
 # This is not used on Darwin.
 set(SWIFT_ENABLE_GOLD_LINKER FALSE CACHE BOOL

cmake/modules/AddSwift.cmake

@@ -888,6 +888,9 @@ function(_add_swift_library_single target name)
      "${SWIFT_SDK_${SWIFTLIB_SINGLE_SDK}_OBJECT_FORMAT}" STREQUAL "ELF")
     list(APPEND link_flags "-fuse-ld=gold")
   endif()
+  if (SWIFT_ENABLE_LLD_LINKER)
+    list(APPEND link_flags "-fuse-ld=lld")
+  endif()
 
   # Configure plist creation for OS X.
   set(PLIST_INFO_PLIST "Info.plist" CACHE STRING "Plist name")
@@ -1530,6 +1533,9 @@ function(_add_swift_executable_single name)
      "${SWIFT_SDK_${SWIFTEXE_SINGLE_SDK}_OBJECT_FORMAT}" STREQUAL "ELF")
     list(APPEND link_flags "-fuse-ld=gold")
   endif()
+  if(SWIFT_ENABLE_LLD_LINKER)
+    list(APPEND link_flags "-fuse-ld=lld")
+  endif()
 
   # Find the names of dependency library targets.
   #

cmake/modules/AddSwiftUnittests.cmake

@@ -54,6 +54,10 @@ function(add_swift_unittest test_dirname)
     set_property(TARGET "${test_dirname}" APPEND_STRING PROPERTY
       LINK_FLAGS " -fuse-ld=gold")
   endif()
+  if(SWIFT_ENABLE_LLD_LINKER)
+    set_property(TARGET "${test_dirname}" APPEND_STRING PROPERTY
+      LINK_FLAGS " -fuse-ld=lld")
+  endif()
 endfunction()