Remove checks for Xcode versions prior to 14.0 and unconditionally enable features that require 14.0 or greater

swift/internal/feature_names.bzl

@@ -200,11 +200,6 @@ SWIFT_FEATURE_USE_GLOBAL_MODULE_CACHE = "swift.use_global_module_cache"
 # This feature requires `swift.use_global_module_cache` to be enabled.
 SWIFT_FEATURE_GLOBAL_MODULE_CACHE_USES_TMPDIR = "swift.global_module_cache_uses_tmpdir"
 
-# If enabled, actions invoking the Swift driver will use the legacy driver
-# instead of the new driver (https://github.com/apple/swift-driver) that
-# launched in Xcode 13/Swift 5.5.
-SWIFT_FEATURE_USE_OLD_DRIVER = "swift.use_old_driver"
-
 # If enabled, Swift linking actions will use `swift-autolink-extract` to extract
 # the linker arguments.  This is required for ELF targets.  This is used
 # internally to determine the behaviour of the actions across different

swift/internal/swift_autoconfiguration.bzl

@@ -39,7 +39,6 @@ load(
     "SWIFT_FEATURE_SUPPORTS_BARE_SLASH_REGEX",
     "SWIFT_FEATURE_USE_AUTOLINK_EXTRACT",
     "SWIFT_FEATURE_USE_MODULE_WRAP",
-    "SWIFT_FEATURE_USE_OLD_DRIVER",
 )
 load(":toolchain_utils.bzl", "SWIFT_TOOLCHAIN_TYPE")
 
@@ -368,9 +367,7 @@ def _create_windows_toolchain(repository_ctx):
         SWIFT_FEATURE_NO_EMBED_DEBUG_MODULE,
         SWIFT_FEATURE_MODULE_MAP_NO_PRIVATE_HEADERS,
     ]
-    disabled_features = [
-        SWIFT_FEATURE_USE_OLD_DRIVER,
-    ]
+    disabled_features = []
 
     version_file = _write_swift_version(repository_ctx, path_to_swiftc)
     xctest_version = repository_ctx.execute([

swift/toolchains/config/compile_config.bzl

@@ -72,7 +72,6 @@ load(
     "SWIFT_FEATURE_USE_EXPLICIT_SWIFT_MODULE_MAP",
     "SWIFT_FEATURE_USE_GLOBAL_INDEX_STORE",
     "SWIFT_FEATURE_USE_GLOBAL_MODULE_CACHE",
-    "SWIFT_FEATURE_USE_OLD_DRIVER",
     "SWIFT_FEATURE_USE_PCH_OUTPUT_DIR",
     "SWIFT_FEATURE_VFSOVERLAY",
     "SWIFT_FEATURE__NUM_THREADS_0_IN_SWIFTCOPTS",
@@ -120,24 +119,8 @@ def compile_action_configs(
         The list of action configs needed to perform compilation.
     """
 
-    #### Flags that control the driver
-    action_configs = [
-        # Use the legacy driver if requested.
-        ActionConfigInfo(
-            actions = [
-                SWIFT_ACTION_COMPILE,
-                SWIFT_ACTION_COMPILE_MODULE_INTERFACE,
-                SWIFT_ACTION_DERIVE_FILES,
-                SWIFT_ACTION_DUMP_AST,
-                SWIFT_ACTION_PRECOMPILE_C_MODULE,
-            ],
-            configurators = [add_arg("-disallow-use-new-driver")],
-            features = [SWIFT_FEATURE_USE_OLD_DRIVER],
-        ),
-    ]
-
     #### Flags that control compilation outputs
-    action_configs += [
+    action_configs = [
         # Emit object file(s).
         ActionConfigInfo(
             actions = [SWIFT_ACTION_COMPILE],

swift/toolchains/swift_toolchain.bzl

@@ -530,7 +530,9 @@ def _swift_toolchain_impl(ctx):
         generated_header_module_implicit_deps_providers = (
             collect_implicit_deps_providers([])
         ),
-        module_aliases = ctx.attr._module_mapping[SwiftModuleAliasesInfo].aliases,
+        module_aliases = (
+            ctx.attr._module_mapping[SwiftModuleAliasesInfo].aliases
+        ),
         implicit_deps_providers = collect_implicit_deps_providers(
             [],
             additional_cc_infos = [swift_linkopts_cc_info],

swift/toolchains/xcode_swift_toolchain.bzl

@@ -487,8 +487,7 @@ def _all_tool_configs(
         execution_requirements,
         generated_header_rewriter,
         swift_executable,
-        toolchain_root,
-        xcode_config):
+        toolchain_root):
     """Returns the tool configurations for the Swift toolchain.
 
     Args:
@@ -501,7 +500,6 @@ def _all_tool_configs(
         swift_executable: A custom Swift driver executable to be used during the
             build, if provided.
         toolchain_root: The root directory of the toolchain, if provided.
-        xcode_config: The `apple_common.XcodeVersionConfig` provider.
 
     Returns:
         A dictionary mapping action name to tool configuration.
@@ -514,15 +512,6 @@ def _all_tool_configs(
         env = dict(env)
         env["TOOLCHAINS"] = custom_toolchain
 
-    # In Xcode 13.3 and 13.4 (Swift 5.6), the legacy driver prints a warning
-    # if it is used. Suppress it, since we still have to use it on those
-    # specific versions due to response file bugs.
-    if (
-        _is_xcode_at_least_version(xcode_config, "13.3") and
-        not _is_xcode_at_least_version(xcode_config, "14.0")
-    ):
-        env["SWIFT_AVOID_WARNING_USING_OLD_DRIVER"] = "1"
-
     def _driver_config(*, mode):
         return {
             "mode": mode,
@@ -747,7 +736,6 @@ def _xcode_swift_toolchain_impl(ctx):
         generated_header_rewriter = generated_header_rewriter,
         swift_executable = swift_executable,
         toolchain_root = toolchain_root,
-        xcode_config = xcode_config,
     )
     all_action_configs = _all_action_configs(
         additional_objc_copts = _command_line_objc_copts(
@@ -786,13 +774,6 @@ def _xcode_swift_toolchain_impl(ctx):
             ),
         )
 
-    module_aliases = ctx.attr._module_mapping[SwiftModuleAliasesInfo].aliases
-    if module_aliases and not _is_xcode_at_least_version(xcode_config, "14.0"):
-        fail(
-            "Module mappings are only supported by Swift 5.7 (Xcode 14.0) " +
-            "and higher.",
-        )
-
     swift_toolchain_info = SwiftToolchainInfo(
         action_configs = all_action_configs,
         cc_toolchain_info = cc_toolchain,
@@ -820,7 +801,9 @@ def _xcode_swift_toolchain_impl(ctx):
             additional_cc_infos = [swift_linkopts_providers.cc_info],
             additional_objc_infos = [swift_linkopts_providers.objc_info],
         ),
-        module_aliases = module_aliases,
+        module_aliases = (
+            ctx.attr._module_mapping[SwiftModuleAliasesInfo].aliases
+        ),
         package_configurations = [
             target[SwiftPackageConfigurationInfo]
             for target in ctx.attr.package_configurations