swift explicit modules examples

examples/apple/objc_interop_modulemap/BUILD

@@ -5,13 +5,26 @@
 load("@rules_cc//cc:objc_library.bzl", "objc_library")
 load("//swift:swift_binary.bzl", "swift_binary")
 load("//swift:swift_library.bzl", "swift_library")
+load("//swift:swift_interop_hint.bzl", "swift_interop_hint")
 
 licenses(["notice"])
 
+swift_interop_hint(
+    name = "PrintStream_swift_interop",
+    module_name = "examples_apple_objc_interop_modulemap_PrintStream",
+    system_pcms = select({
+        # this lets objc library to depend on the same system_sdks as the swift library
+        "//conditions:default": [
+            "@build_bazel_rules_swift//system_sdks:system_sdks",
+        ],
+    }),
+)
+
 objc_library(
     name = "PrintStream",
     srcs = ["OIPrintStream.m"],
     hdrs = ["OIPrintStream.h"],
+    aspect_hints = [":PrintStream_swift_interop"],
     target_compatible_with = ["@platforms//os:macos"],
 )
 

swift/internal/compiling.bzl

@@ -730,6 +730,7 @@ to use swift_common.compile(include_dev_srch_paths = ...) instead.\
         feature_configuration = feature_configuration,
         feature_name = SWIFT_FEATURE_NO_GENERATED_MODULE_MAP,
     ):
+
         compilation_context_to_compile = (
             compilation_context_for_explicit_module_compilation(
                 compilation_contexts = [

swift/internal/swift_interop_info.bzl

@@ -71,6 +71,10 @@ be disabled when the aspect processes that target; for example, a rule that
 processes frameworks with headers that do not follow strict layering can request
 that `swift.strict_module` always be disabled for its targets even if it is
 enabled by default in the toolchain.
+""",
+        "system_pcms": """\
+A list of precompiled clang modules with `SwiftInfo` providers for system modules.
+This is used to pass `system_pcm` dependencies originating from `swift_interop_hint`.
 """,
     },
 )

swift/swift_clang_module_aspect.bzl

@@ -408,7 +408,7 @@ def _handle_module(
     )
 
     output_groups = {}
-
+    
     pcm_outputs = precompile_clang_module(
         actions = aspect_ctx.actions,
         cc_compilation_context = compilation_context_to_compile,
@@ -420,6 +420,7 @@ def _handle_module(
         target_name = target.label.name,
         toolchain_type = toolchain_type,
     )
+
     precompiled_module = getattr(pcm_outputs, "pcm_file", None)
     pcm_indexstore = getattr(pcm_outputs, "indexstore_directory", None)
 
@@ -734,6 +735,10 @@ def _swift_clang_module_aspect_impl(target, aspect_ctx, toolchain_type):
         if interop_info.suppressed:
             return providers
 
+        # Add system_pcms passed via `swift_interop_hint` to swift_infos 
+        for system_pcm in interop_info.system_pcms:
+            swift_infos.append(system_pcm[SwiftInfo])
+
         exclude_headers = interop_info.exclude_headers
         module_map_file = interop_info.module_map
         module_name = (

swift/swift_interop_hint.bzl

@@ -24,6 +24,7 @@ def _swift_interop_hint_impl(ctx):
         module_map = ctx.file.module_map,
         module_name = ctx.attr.module_name,
         suppressed = ctx.attr.suppressed,
+        system_pcms = ctx.attr.system_pcms,
     )
 
 swift_interop_hint = rule(
@@ -73,6 +74,14 @@ other non-identifier characters with underscores.
             doc = """\
 If `True`, the hinted target should suppress any module that it would otherwise
 generate.
+""",
+            mandatory = False,
+        ),
+        "system_pcms": attr.label_list(
+            doc = """\
+A list of precompiled clang modules with `SwiftInfo` providers for system modules.
+This is used to define system pcm dependencies and eventually propagated to swift_interop_info.
+swift_interop_info will pass those to compile actions. 
 """,
             mandatory = False,
         ),

swift/swift_interop_info.bzl

@@ -38,7 +38,8 @@ def create_swift_interop_info(
         requested_features = [],
         suppressed = False,
         swift_infos = [],
-        unsupported_features = []):
+        unsupported_features = [],
+        system_pcms = []):
     """Returns a provider that lets a target expose C/Objective-C APIs to Swift.
 
     The provider returned by this function allows custom build rules written in
@@ -107,6 +108,9 @@ def create_swift_interop_info(
             strict layering can request that `swift.strict_module` always be
             disabled for its targets even if it is enabled by default in the
             toolchain.
+        system_pcms: A list of precompiled clang modules with `SwiftInfo`
+            providers for system modules. This is used to define system pcm 
+            dependencies passed from `swift_interop_hint`.
 
     Returns:
         A provider whose type/layout is an implementation detail and should not
@@ -128,4 +132,5 @@ def create_swift_interop_info(
         suppressed = suppressed,
         swift_infos = swift_infos,
         unsupported_features = unsupported_features,
+        system_pcms = system_pcms,
     )

swift/swift_library.bzl

@@ -33,8 +33,10 @@ load(
     "SWIFT_FEATURE_EMIT_PRIVATE_SWIFTINTERFACE",
     "SWIFT_FEATURE_EMIT_SWIFTINTERFACE",
     "SWIFT_FEATURE_ENABLE_LIBRARY_EVOLUTION",
+    "SWIFT_FEATURE_USE_C_MODULES",
+    "SWIFT_FEATURE_EMIT_C_MODULE",
 )
-load("//swift/internal:features.bzl", "configure_features")
+load("//swift/internal:features.bzl", "configure_features", "is_feature_enabled")
 load(
     "//swift/internal:linking.bzl",
     "create_linking_context_from_compilation_outputs",
@@ -159,6 +161,18 @@ def _swift_library_impl(ctx):
     swift_infos = get_providers(deps, SwiftInfo)
     private_swift_infos = get_providers(private_deps, SwiftInfo)
 
+    if is_feature_enabled(
+        feature_configuration = feature_configuration,
+        feature_name = SWIFT_FEATURE_USE_C_MODULES,
+    ) and is_feature_enabled(
+        feature_configuration = feature_configuration,
+        feature_name = SWIFT_FEATURE_EMIT_C_MODULE,
+    ):
+        # only add system_deps if both features are enabled
+        system_deps = ctx.attr.system_deps
+        system_swift_infos = get_providers(system_deps, SwiftInfo)
+        swift_infos.extend(system_swift_infos)
+
     if ctx.attr.generates_header:
         generated_header_name = (
             ctx.attr.generated_header_name or
@@ -288,6 +302,20 @@ dependent for linking, but artifacts/flags required for compilation (such as
             # TODO(b/301253335): Once AEGs are enabled in Bazel, set the swift toolchain type in the
             # exec configuration of `plugins` attribute and enable AEGs in swift_library.
             "_use_auto_exec_groups": attr.bool(default = False),
+            # TODO : system deps
+            "system_deps": swift_deps_attr(
+                aspects = [swift_clang_module_aspect],
+                doc = """\
+Default and universal system modules necessary for Swift compilation with explicit C modules.
+It's desired that each swift_library rule target defines its own system module dependencies, 
+however, we are defining a long list of commonly used system modules here just to ease the burden 
+of the developers during the migration to explicit C modules. This attribute should be removed once 
+the explicit c modules are fully adopted and enabled by default.
+""",
+                default = [
+                    "//system_sdks:system_sdks",
+                ],
+            )
         },
     ),
     doc = """\

swift/toolchains/config/compile_config.bzl

@@ -1348,6 +1348,7 @@ def compile_action_configs(
                     SWIFT_ACTION_COMPILE_MODULE_INTERFACE,
                     SWIFT_ACTION_DERIVE_FILES,
                     SWIFT_ACTION_DUMP_AST,
+                    SWIFT_ACTION_PRECOMPILE_C_MODULE,
                 ],
                 configurators = [
                     lambda _, args: args.add_all(

system_sdks/16.3.0.16E140/BUILD

@@ -0,0 +1,104 @@
+load("@build_bazel_rules_swift//swift:swift.bzl", "swift_library_group")
+package(default_visibility = ["//visibility:public"])
+
+config_setting(
+    name = "macos_x86_64",
+    constraint_values = [
+        "@platforms//os:macos",
+        "@platforms//cpu:x86_64",
+    ],
+)
+
+config_setting(
+    name = "macos_arm64",
+    constraint_values = [
+        "@platforms//os:macos",
+        "@platforms//cpu:arm64",
+    ],
+)
+
+config_setting(
+    name = "ios_device_arm64",
+    constraint_values = [
+        "@platforms//os:ios",
+        "@platforms//cpu:arm64",
+        "@build_bazel_apple_support//constraints:device",
+    ],
+)
+
+config_setting(
+    name = "ios_sim_x86_64",
+    constraint_values = [
+        "@platforms//os:ios",
+        "@platforms//cpu:x86_64",
+        "@build_bazel_apple_support//constraints:simulator",
+    ],
+)
+
+config_setting(
+    name = "ios_sim_arm64",
+    constraint_values = [
+        "@platforms//os:ios",
+        "@platforms//cpu:arm64",
+        "@build_bazel_apple_support//constraints:simulator",
+    ],
+)
+
+config_setting(
+    name = "watchos_sim_arm64",
+    constraint_values = [
+        "@platforms//os:watchos",
+        "@platforms//cpu:arm64",
+        "@build_bazel_apple_support//constraints:simulator",
+    ],
+)
+
+config_setting(
+    name = "watchos_sim_x86_64",
+    constraint_values = [
+        "@platforms//os:watchos",
+        "@platforms//cpu:x86_64",
+        "@build_bazel_apple_support//constraints:simulator",
+    ],
+)
+
+config_setting(
+    name = "watchos_device_arm64_32",
+    constraint_values = [
+        "@platforms//os:watchos",
+        "@platforms//cpu:arm64_32",
+        "@build_bazel_apple_support//constraints:device",
+    ],
+)
+
+swift_library_group(
+    name = "system_sdks",
+    deps = select({
+        "ios_device_arm64": ["//system_sdks/16.3.0.16E140/iPhoneOS/arm64:all_generated_targets"],
+        "watchos_device_arm64_32": ["//system_sdks/16.3.0.16E140/WatchOS/arm64_32:all_generated_targets"],
+        "watchos_sim_arm64": ["//system_sdks/16.3.0.16E140/WatchSimulator/arm64:all_generated_targets"],
+        "watchos_sim_x86_64": ["//system_sdks/16.3.0.16E140/WatchSimulator/x86_64:all_generated_targets"],
+        "ios_sim_arm64": ["//system_sdks/16.3.0.16E140/iPhoneSimulator/arm64:all_generated_targets"],
+        "ios_sim_x86_64": ["//system_sdks/16.3.0.16E140/iPhoneSimulator/x86_64:all_generated_targets"],
+        "macos_arm64": ["//system_sdks/16.3.0.16E140/MacOSX/arm64:all_generated_targets"],
+        "macos_x86_64": ["//system_sdks/16.3.0.16E140/MacOSX/x86_64:all_generated_targets"],
+        "//conditions:default": [],
+    }),
+)
+
+
+swift_library_group(
+    name = "testonly_system_sdks",
+    testonly = True,
+    deps = select({
+        "ios_device_arm64": ["//system_sdks/16.3.0.16E140/iPhoneOS/arm64:all_generated_testonly_targets"],
+        "watchos_device_arm64_32": ["//system_sdks/16.3.0.16E140/WatchOS/arm64_32:all_generated_testonly_targets"],
+        "watchos_sim_arm64": ["//system_sdks/16.3.0.16E140/WatchSimulator/arm64:all_generated_testonly_targets"],
+        "watchos_sim_x86_64": ["//system_sdks/16.3.0.16E140/WatchSimulator/x86_64:all_generated_testonly_targets"],
+        "ios_sim_arm64": ["//system_sdks/16.3.0.16E140/iPhoneSimulator/arm64:all_generated_testonly_targets"],
+        "ios_sim_x86_64": ["//system_sdks/16.3.0.16E140/iPhoneSimulator/x86_64:all_generated_testonly_targets"],
+        "macos_arm64": ["//system_sdks/16.3.0.16E140/MacOSX/arm64:all_generated_testonly_targets"],
+        "macos_x86_64": ["//system_sdks/16.3.0.16E140/MacOSX/x86_64:all_generated_testonly_targets"],
+        "//conditions:default": [],
+    }),
+)