commit 9ed67668564257c27e49ff7a07fac0b23f27ba85
Date: Mon, 26 Oct 2020 23:13:22 +0530
Subject: [build-script] Move --native-{clang,llvm,swift}-tools-path
 flags into the Python build-script

Also, fix two places where the LLVM path was wrongly employed to set up clang,
and use the Swift path in install_toolchain_path().

diff --git a/swift/stdlib/CMakeLists.txt b/swift/stdlib/CMakeLists.txt
index 81cad0966a1d..a0e3b138809f 100644
--- a/swift/stdlib/CMakeLists.txt
+++ b/swift/stdlib/CMakeLists.txt
@@ -102,11 +102,11 @@ else()
   # If we use Clang-cl or MSVC, CMake provides default compiler and linker flags that are incompatible
   # with the frontend of Clang or Clang++.
   if(SWIFT_COMPILER_IS_MSVC_LIKE)
-    set(CMAKE_CXX_COMPILER "${SWIFT_NATIVE_LLVM_TOOLS_PATH}/clang-cl")
-    set(CMAKE_C_COMPILER "${SWIFT_NATIVE_LLVM_TOOLS_PATH}/clang-cl")
+    set(CMAKE_CXX_COMPILER "${SWIFT_NATIVE_CLANG_TOOLS_PATH}/clang-cl")
+    set(CMAKE_C_COMPILER "${SWIFT_NATIVE_CLANG_TOOLS_PATH}/clang-cl")
   else()
-    set(CMAKE_CXX_COMPILER "${SWIFT_NATIVE_LLVM_TOOLS_PATH}/clang++")
-    set(CMAKE_C_COMPILER "${SWIFT_NATIVE_LLVM_TOOLS_PATH}/clang")
+    set(CMAKE_CXX_COMPILER "${SWIFT_NATIVE_CLANG_TOOLS_PATH}/clang++")
+    set(CMAKE_C_COMPILER "${SWIFT_NATIVE_CLANG_TOOLS_PATH}/clang")
   endif()
 
   if(CMAKE_C_COMPILER_LAUNCHER MATCHES ".*distcc")
diff --git a/swift/utils/build-script b/swift/utils/build-script
index 639f790fe354..9ccb8ef6e2dc 100755
--- a/swift/utils/build-script
+++ b/swift/utils/build-script
@@ -704,6 +704,18 @@ class BuildScriptInvocation(object):
             impl_args += [
                 "--host-libtool", toolchain.libtool,
             ]
+        if args.native_clang_tools_path is not None:
+            impl_args += [
+                "--native-clang-tools-path=%s" % args.native_clang_tools_path
+            ]
+        if args.native_llvm_tools_path is not None:
+            impl_args += [
+                "--native-llvm-tools-path=%s" % args.native_llvm_tools_path
+            ]
+        if args.native_swift_tools_path is not None:
+            impl_args += [
+                "--native-swift-tools-path=%s" % args.native_swift_tools_path
+            ]
 
         # If we have extra_swift_args, combine all of them together and then
         # add them as one command.
diff --git a/swift/utils/build_swift/build_swift/driver_arguments.py b/swift/utils/build_swift/build_swift/driver_arguments.py
index cb1c5c0b0e38..73fbd7c95e18 100644
--- a/swift/utils/build_swift/build_swift/driver_arguments.py
+++ b/swift/utils/build_swift/build_swift/driver_arguments.py
@@ -374,6 +374,15 @@ def create_argument_parser():
     option('--host-cxx', store_path(executable=True),
            help='the absolute path to CXX, the "clang++" compiler for the '
                 'host platform. Default is auto detected.')
+    option('--native-swift-tools-path', store_path,
+           help='the path to a directory that contains prebuilt Swift tools '
+                'that are executable on the host platform')
+    option('--native-clang-tools-path', store_path,
+           help='the path to a directory that contains prebuilt Clang tools '
+                'that are executable on the host platform')
+    option('--native-llvm-tools-path', store_path,
+           help='the path to a directory that contains prebuilt LLVM tools '
+                'that are executable on the host platform')
     option('--cmake-c-launcher', store_path(executable=True),
            default=os.environ.get('C_COMPILER_LAUNCHER', None),
            help='the absolute path to set CMAKE_C_COMPILER_LAUNCHER')
diff --git a/swift/utils/swift_build_support/swift_build_support/products/product.py b/swift/utils/swift_build_support/swift_build_support/products/product.py
index ba6f673bb6c9..001e2bf03083 100644
--- a/swift/utils/swift_build_support/swift_build_support/products/product.py
+++ b/swift/utils/swift_build_support/swift_build_support/products/product.py
@@ -169,6 +169,9 @@ def install_toolchain_path(self, host_target):
         Returns the path to the toolchain that is being created as part of this
         build.
         """
+        if self.args.native_swift_tools_path is not None:
+            return os.path.split(self.args.native_swift_tools_path)[0]
+
         install_destdir = self.args.install_destdir
         if self.args.cross_compile_hosts:
             build_root = os.path.dirname(self.build_dir)