Replace --swiftcopt with starlark flag

swift/BUILD

@@ -3,6 +3,7 @@ load("@bazel_skylib//rules:common_settings.bzl", "bool_flag", "bool_setting")
 load(
  "//swift/internal:build_settings.bzl",
  "per_module_swiftcopt_flag",
+ "repeatable_string_flag",
 )
 
 package(default_visibility = ["//visibility:public"])
@@ -81,6 +82,24 @@ filegroup(
  ],
 )
 
+# Additional Swift compiler flags that will be applied to all `SwiftCompile`
+# actions in non-execution configurations (but not module interface compile
+# actions or Clang module compile actions).
+repeatable_string_flag(
+ name = "copt",
+ build_setting_default = [],
+ visibility = ["//visibility:public"],
+)
+
+# Additional Swift compiler flags that will be applied to all `SwiftCompile`
+# actions in execution configurations (but not module interface compile
+# actions or Clang module compile actions).
+repeatable_string_flag(
+ name = "exec_copt",
+ build_setting_default = [],
+ visibility = ["//visibility:public"],
+)
+
 # User settable flag that specifies additional Swift copts on a per-swiftmodule basis.
 per_module_swiftcopt_flag(
  name = "per_module_swiftcopt",

swift/internal/BUILD

@@ -424,6 +424,7 @@ bzl_library(
 bzl_library(
  name = "build_settings",
  srcs = ["build_settings.bzl"],
+ deps = ["@bazel_skylib//rules:common_settings"],
 )
 
 # Indirection needed to prevent using `objc_library` outside of macOS

swift/internal/build_settings.bzl

@@ -14,6 +14,25 @@
 
 """Custom build settings rules for Swift rules."""
 
+load("@bazel_skylib//rules:common_settings.bzl", "BuildSettingInfo")
+
+def _repeatable_string_flag_impl(ctx):
+ return BuildSettingInfo(value = ctx.build_setting_value)
+
+repeatable_string_flag = rule(
+ build_setting = config.string_list(
+ flag = True,
+ repeatable = True,
+ ),
+ doc = """\
+A string-valued flag that can occur on the command line multiple times, used for
+flags like `copt`. This allows flags to be stacked in `--config`s (rather than
+overwriting previous occurrences) and also makes no assumption about the values
+of the flags (comma-splitting does not occur).
+""",
+ implementation = _repeatable_string_flag_impl,
+)
+
 PerModuleSwiftCoptSettingInfo = provider(
  doc = "A provider for the parsed per-swiftmodule swift copts.",
  fields = {

swift/internal/swift_toolchain.bzl

@@ -21,6 +21,7 @@ toolchain, see `swift.bzl`.
 
 load("@bazel_skylib//lib:dicts.bzl", "dicts")
 load("@bazel_skylib//lib:paths.bzl", "paths")
+load("@bazel_skylib//rules:common_settings.bzl", "BuildSettingInfo")
 load("@bazel_tools//tools/cpp:toolchain_utils.bzl", "find_cpp_toolchain")
 load(":actions.bzl", "swift_action_names")
 load(":attrs.bzl", "swift_toolchain_driver_attrs")
@@ -292,11 +293,19 @@ def _swift_toolchain_impl(ctx):
  toolchain_root,
  )
 
+ # TODO: b/312204041 - Remove the use of the `swift` fragment once we've
+ # migrated the `--swiftcopt` flag via `--flag_alias`.
+ swiftcopts = list(ctx.fragments.swift.copts())
+ if "-exec-" in ctx.bin_dir.path:
+ swiftcopts.extend(ctx.attr._exec_copts[BuildSettingInfo].value)
+ else:
+ swiftcopts.extend(ctx.attr._copts[BuildSettingInfo].value)
+
  # Combine build mode features, autoconfigured features, and required
  # features.
  requested_features = (
  features_for_build_modes(ctx) +
- features_from_swiftcopts(swiftcopts = ctx.fragments.swift.copts())
+ features_from_swiftcopts(swiftcopts = swiftcopts)
  )
  requested_features.extend([
  SWIFT_FEATURE_CACHEABLE_SWIFTMODULES,
@@ -330,7 +339,7 @@ def _swift_toolchain_impl(ctx):
  arch = ctx.attr.arch,
  sdkroot = ctx.attr.sdkroot,
  xctest_version = ctx.attr.xctest_version,
- additional_swiftc_copts = ctx.fragments.swift.copts(),
+ additional_swiftc_copts = swiftcopts,
  )
 
  if ctx.attr.os == "windows":
@@ -441,6 +450,20 @@ configuration options that are applied to targets on a per-package basis.
  doc = """\
 The C++ toolchain from which other tools needed by the Swift toolchain (such as
 `clang` and `ar`) will be retrieved.
+""",
+ ),
+ "_copts": attr.label(
+ default = Label("@build_bazel_rules_swift//swift:copt"),
+ doc = """\
+The label of the `string_list` containing additional flags that should be passed
+to the compiler.
+""",
+ ),
+ "_exec_copts": attr.label(
+ default = Label("@build_bazel_rules_swift//swift:exec_copt"),
+ doc = """\
+The label of the `string_list` containing additional flags that should be passed
+to the compiler for exec transition builds.
 """,
  ),
  "_worker": attr.label(

swift/internal/xcode_swift_toolchain.bzl

@@ -22,6 +22,7 @@ toolchain, see `swift.bzl`.
 load("@bazel_skylib//lib:dicts.bzl", "dicts")
 load("@bazel_skylib//lib:partial.bzl", "partial")
 load("@bazel_skylib//lib:paths.bzl", "paths")
+load("@bazel_skylib//rules:common_settings.bzl", "BuildSettingInfo")
 load("@bazel_tools//tools/cpp:toolchain_utils.bzl", "find_cpp_toolchain")
 load(":actions.bzl", "swift_action_names")
 load(":attrs.bzl", "swift_toolchain_driver_attrs")
@@ -551,6 +552,14 @@ def _xcode_swift_toolchain_impl(ctx):
 
  xcode_config = ctx.attr._xcode_config[apple_common.XcodeVersionConfig]
 
+ # TODO: b/312204041 - Remove the use of the `swift` fragment once we've
+ # migrated the `--swiftcopt` flag via `--flag_alias`.
+ swiftcopts = list(ctx.fragments.swift.copts())
+ if "-exec-" in ctx.bin_dir.path:
+ swiftcopts.extend(ctx.attr._exec_copts[BuildSettingInfo].value)
+ else:
+ swiftcopts.extend(ctx.attr._copts[BuildSettingInfo].value)
+
  # `--define=SWIFT_USE_TOOLCHAIN_ROOT=<path>` is a rapid development feature
  # that lets you build *just* a custom `swift` driver (and `swiftc`
  # symlink), rather than a full toolchain, and point compilation actions at
@@ -589,7 +598,7 @@ def _xcode_swift_toolchain_impl(ctx):
  requested_features = features_for_build_modes(
  ctx,
  cpp_fragment = cpp_fragment,
- ) + features_from_swiftcopts(swiftcopts = ctx.fragments.swift.copts())
+ ) + features_from_swiftcopts(swiftcopts = swiftcopts)
  requested_features.extend(ctx.features)
  requested_features.extend([
  SWIFT_FEATURE_BUNDLED_XCTESTS,
@@ -640,7 +649,7 @@ def _xcode_swift_toolchain_impl(ctx):
  ctx.fragments.cpp,
  ctx.fragments.objc,
  ),
- additional_swiftc_copts = ctx.fragments.swift.copts(),
+ additional_swiftc_copts = swiftcopts,
  apple_toolchain = apple_toolchain,
  generated_header_rewriter = generated_header_rewriter,
  needs_resource_directory = swift_executable or toolchain_root,
@@ -783,6 +792,20 @@ configuration options that are applied to targets on a per-package basis.
  doc = """\
 The C++ toolchain from which linking flags and other tools needed by the Swift
 toolchain (such as `clang`) will be retrieved.
+""",
+ ),
+ "_copts": attr.label(
+ default = Label("@build_bazel_rules_swift//swift:copt"),
+ doc = """\
+The label of the `string_list` containing additional flags that should be passed
+to the compiler.
+""",
+ ),
+ "_exec_copts": attr.label(
+ default = Label("@build_bazel_rules_swift//swift:exec_copt"),
+ doc = """\
+The label of the `string_list` containing additional flags that should be passed
+to the compiler for exec transition builds.
 """,
  ),
  "_worker": attr.label(