Internal change

PiperOrigin-RevId: 540589258

examples/xplatform/macros/BUILD

@@ -0,0 +1,57 @@
+load(
+    "//swift:swift_binary.bzl",
+    "swift_binary",
+)
+load(
+    "//swift:swift_compiler_plugin.bzl",
+    "swift_compiler_plugin",
+)
+load(
+    "//swift:swift_library.bzl",
+    "swift_library",
+)
+load(
+    "//swift:swift_test.bzl",
+    "swift_test",
+)
+
+licenses(["notice"])
+
+swift_library(
+    name = "stringify",
+    srcs = ["Stringify.swift"],
+    module_name = "Stringify",
+    plugins = [":stringify_macro"],
+)
+
+swift_compiler_plugin(
+    name = "stringify_macro",
+    srcs = [
+        "StringifyMacro.swift",
+        "StringifyMacroPlugin.swift",
+    ],
+    module_name = "StringifyMacroPlugin",
+    deps = [
+        "@SwiftSyntax",
+        "@SwiftSyntax//:SwiftCompilerPlugin",
+        "@SwiftSyntax//:SwiftSyntaxBuilder",
+        "@SwiftSyntax//:SwiftSyntaxMacros",
+    ],
+)
+
+swift_binary(
+    name = "stringify_client",
+    srcs = ["StringifyClient.swift"],
+    deps = [":stringify"],
+)
+
+swift_test(
+    name = "stringify_macro_test",
+    srcs = ["StringifyMacroTests.swift"],
+    deps = [
+        ":stringify_macro",
+        "@SwiftSyntax",
+        "@SwiftSyntax//:SwiftSyntaxBuilder",
+        "@SwiftSyntax//:SwiftSyntaxMacros",
+    ],
+)

examples/xplatform/macros/Stringify.swift

@@ -0,0 +1,17 @@
+// Copyright 2023 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+@freestanding(expression)
+public macro stringify<T>(_ value: T) -> (T, String) =
+  #externalMacro(module: "StringifyMacroPlugin", type: "StringifyMacro")

examples/xplatform/macros/StringifyClient.swift

@@ -0,0 +1,17 @@
+// Copyright 2023 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import Stringify
+
+print(#stringify(1 + 2))

examples/xplatform/macros/StringifyMacro.swift

@@ -0,0 +1,29 @@
+// Copyright 2023 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import SwiftSyntax
+import SwiftSyntaxBuilder
+import SwiftSyntaxMacros
+
+public struct StringifyMacro: ExpressionMacro {
+  public static func expansion(
+    of node: some FreestandingMacroExpansionSyntax,
+    in context: some MacroExpansionContext
+  ) -> ExprSyntax {
+    guard let argument = node.argumentList.first?.expression else {
+      fatalError("compiler bug: the macro does not have any arguments")
+    }
+    return "(\(argument), \(literal: argument.description))"
+  }
+}

examples/xplatform/macros/StringifyMacroPlugin.swift

@@ -0,0 +1,25 @@
+// Copyright 2023 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#if canImport(SwiftCompilerPlugin)
+import SwiftCompilerPlugin
+import SwiftSyntaxMacros
+
+@main
+struct StringifyMacroPlugin: CompilerPlugin {
+  let providingMacros: [Macro.Type] = [
+    StringifyMacro.self
+  ]
+}
+#endif

examples/xplatform/macros/StringifyMacroTests.swift

@@ -0,0 +1,38 @@
+// Copyright 2023 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import SwiftSyntax
+import SwiftSyntaxBuilder
+import SwiftSyntaxMacros
+import StringifyMacroPlugin
+import XCTest
+
+class StringifyMacroTests: XCTestCase {
+  func testStringify() {
+    let sourceFile: SourceFileSyntax = #"""
+      _ = #stringify(1 + 2)
+      """#
+    let context = BasicMacroExpansionContext(
+      sourceFiles: [sourceFile: .init(moduleName: "TestModule", fullFilePath: "Test.swift")]
+    )
+    let transformedSourceFile =
+      sourceFile.expand(macros: ["stringify": StringifyMacro.self], in: context)
+    XCTAssertEqual(
+      String(describing: transformedSourceFile),
+      #"""
+      _ = (1 + 2, "1 + 2")
+      """#
+    )
+  }
+}

swift/BUILD

@@ -34,6 +34,7 @@ bzl_library(
         ":providers",
         "//swift/internal:compiling",
         "//swift/internal:linking",
+        "//swift/internal:providers",
         "//swift/internal:toolchain_utils",
         "//swift/internal:utils",
     ],
@@ -70,6 +71,21 @@ bzl_library(
     ],
 )
 
+bzl_library(
+    name = "swift_compiler_plugin",
+    srcs = ["swift_compiler_plugin.bzl"],
+    deps = [
+        ":module_name",
+        ":providers",
+        "//swift/internal:compiling",
+        "//swift/internal:linking",
+        "//swift/internal:providers",
+        "//swift/internal:toolchain_utils",
+        "//swift/internal:utils",
+        "@bazel_skylib//lib:dicts",
+    ],
+)
+
 bzl_library(
     name = "swift_cross_import_overlay",
     srcs = ["swift_cross_import_overlay.bzl"],
@@ -158,6 +174,7 @@ bzl_library(
         "//swift/internal:feature_names",
         "//swift/internal:features",
         "//swift/internal:linking",
+        "//swift/internal:providers",
         "//swift/internal:toolchain_utils",
         "//swift/internal:utils",
         "@bazel_skylib//lib:dicts",
@@ -216,8 +233,8 @@ bzl_library(
         ":module_name",
         ":providers",
         "//swift/internal:compiling",
-        "//swift/internal:features",
         "//swift/internal:linking",
+        "//swift/internal:providers",
         "//swift/internal:swift_symbol_graph_aspect",
         "//swift/internal:symbol_graph_extracting",
         "//swift/internal:toolchain_utils",

swift/internal/BUILD

@@ -27,6 +27,7 @@ bzl_library(
     name = "attrs",
     srcs = ["attrs.bzl"],
     deps = [
+        ":providers",
         "//swift:providers",
         "@bazel_skylib//lib:dicts",
     ],
@@ -122,6 +123,9 @@ bzl_library(
 bzl_library(
     name = "providers",
     srcs = ["providers.bzl"],
+    visibility = [
+        "//swift:__subpackages__",
+    ],
 )
 
 bzl_library(

swift/internal/attrs.bzl

@@ -16,12 +16,15 @@
 
 load("@build_bazel_rules_swift//swift:providers.bzl", "SwiftInfo")
 load("@bazel_skylib//lib:dicts.bzl", "dicts")
+load(":providers.bzl", "SwiftCompilerPluginInfo")
 
 visibility([
     "@build_bazel_rules_swift//swift/...",
 ])
 
-def swift_common_rule_attrs(additional_deps_aspects = []):
+def swift_common_rule_attrs(
+        additional_deps_aspects = [],
+        additional_deps_providers = []):
     return {
         "data": attr.label_list(
             allow_files = True,
@@ -34,6 +37,7 @@ binary or library, or other programs needed by it.
 """,
         ),
         "deps": swift_deps_attr(
+            additional_deps_providers = additional_deps_providers,
             aspects = additional_deps_aspects,
             doc = """\
 A list of targets that are dependencies of the target being built, which will be
@@ -52,6 +56,7 @@ indirect (transitive) dependents.
 
 def swift_compilation_attrs(
         additional_deps_aspects = [],
+        additional_deps_providers = [],
         requires_srcs = True):
     """Returns an attribute dictionary for rules that compile Swift code.
 
@@ -85,6 +90,9 @@ def swift_compilation_attrs(
             by the individual rules to avoid potential circular dependencies
             between the API and the aspects; the API loaded the aspects
             directly, then those aspects would not be able to load the API.
+        additional_deps_providers: A list of lists representing additional
+            providers that should be allowed by the `deps` attribute of the
+            rule.
         requires_srcs: Indicates whether the `srcs` attribute should be marked
             as mandatory and non-empty. Defaults to `True`.
 
@@ -96,6 +104,7 @@ def swift_compilation_attrs(
     return dicts.add(
         swift_common_rule_attrs(
             additional_deps_aspects = additional_deps_aspects,
+            additional_deps_providers = additional_deps_providers,
         ),
         swift_toolchain_attrs(),
         {
@@ -138,6 +147,14 @@ build label, by stripping the leading `//` and replacing `/`, `:`, and other
 non-identifier characters with underscores.
 """,
             ),
+            "plugins": attr.label_list(
+                cfg = "exec",
+                doc = """\
+A list of `swift_compiler_plugin` targets that should be loaded by the compiler
+when compiling this module and any modules that directly depend on it.
+""",
+                providers = [[SwiftCompilerPluginInfo]],
+            ),
             "swiftc_inputs": attr.label_list(
                 allow_files = True,
                 doc = """\
@@ -164,13 +181,16 @@ def swift_config_attrs():
         ),
     }
 
-def swift_deps_attr(doc, **kwargs):
+def swift_deps_attr(*, additional_deps_providers = [], doc, **kwargs):
     """Returns an attribute suitable for representing Swift rule dependencies.
 
     The returned attribute will be configured to accept targets that propagate
     `CcInfo` or `SwiftInfo` providers.
 
     Args:
+        additional_deps_providers: A list of lists representing additional
+            providers that should be allowed by the `deps` attribute of the
+            rule.
         doc: A string containing a summary description of the purpose of the
             attribute. This string will be followed by additional text that
             lists the permitted kinds of targets that may go in this attribute.
@@ -189,7 +209,7 @@ Allowed kinds of dependencies are:
 
 *   `cc_library` and `objc_library` (or anything propagating `CcInfo`)
 """,
-        providers = [[CcInfo], [SwiftInfo]],
+        providers = [[CcInfo], [SwiftInfo]] + additional_deps_providers,
         **kwargs
     )
 

swift/internal/compiling.bzl

@@ -216,6 +216,7 @@ def compile(
         feature_configuration,
         generated_header_name = None,
         module_name,
+        plugins = [],
         private_swift_infos = [],
         srcs,
         swift_infos,
@@ -249,6 +250,8 @@ def compile(
         module_name: The name of the Swift module being compiled. This must be
             present and valid; use `derive_swift_module_name` to generate a
             default from the target's label if needed.
+        plugins: A list of `SwiftCompilerPluginInfo` providers that represent
+            plugins that should be loaded by the compiler.
         private_swift_infos: A list of `SwiftInfo` providers from private
             (implementation-only) dependencies of the target being compiled. The
             modules defined by these providers are used as dependencies of the
@@ -428,6 +431,18 @@ def compile(
     else:
         deps_modules_file = None
 
+    # As of the time of this writing (Xcode 15.0), macros are the only kind of
+    # plugins that are available. Since macros do source-level transformations,
+    # we only need to load plugins directly used by the module being compiled.
+    # Plugins that are only used by transitive dependencies do *not* need to be
+    # passed; the compiler does not attempt to load them when deserializing
+    # modules.
+    used_plugins = list(plugins)
+    for swift_info in swift_infos:
+        for module_context in swift_info.direct_modules:
+            if module_context.swift and module_context.swift.plugins:
+                used_plugins.extend(module_context.swift.plugins)
+
     prerequisites = struct(
         additional_inputs = additional_inputs,
         always_include_headers = is_feature_enabled(
@@ -443,6 +458,7 @@ def compile(
         is_swift = True,
         module_name = module_name,
         original_module_name = original_module_name,
+        plugins = used_plugins,
         source_files = srcs,
         target_label = feature_configuration._label,
         transitive_modules = transitive_modules,
@@ -521,6 +537,7 @@ def compile(
         swift = create_swift_module_inputs(
             defines = defines,
             original_module_name = original_module_name,
+            plugins = plugins,
             swiftdoc = compile_outputs.swiftdoc_file,
             swiftinterface = compile_outputs.swiftinterface_file,
             swiftmodule = compile_outputs.swiftmodule_file,