Propagate Swift-specific linker flags as an implicit dependency of the toolchain.

apple/apple_binary.bzl

@@ -22,14 +22,6 @@ load(
     "@build_bazel_rules_apple//apple/internal:rule_factory.bzl",
     "rule_factory",
 )
-load(
-    "@build_bazel_rules_apple//apple/internal:swift_support.bzl",
-    "swift_support",
-)
-load(
-    "@build_bazel_rules_swift//swift:swift.bzl",
-    "swift_common",
-)
 
 def _linker_flag_for_sdk_dylib(dylib):
     """Returns a linker flag suitable for linking the given `sdk_dylib` value.
@@ -60,16 +52,6 @@ def _apple_binary_impl(ctx):
         for framework in ctx.attr.weak_sdk_frameworks
     ]
 
-    deps = getattr(ctx.attr, "deps", [])
-    swift_usage_info = swift_support.swift_usage_info(deps)
-    if swift_usage_info:
-        swift_linkopts = swift_common.swift_runtime_linkopts(
-            is_static = False,
-            is_test = False,
-            toolchain = swift_usage_info.toolchain,
-        )
-        extra_linkopts.extend(swift_linkopts)
-
     link_result = linking_support.register_linking_action(
         ctx,
         extra_linkopts = extra_linkopts,

apple/internal/apple_framework_import.bzl

@@ -174,12 +174,15 @@ def _grouped_framework_files(framework_imports):
 
     return framework_groups
 
-def _objc_provider_with_dependencies(ctx, objc_provider_fields):
+def _objc_provider_with_dependencies(ctx, objc_provider_fields, additional_objc_infos = []):
     """Returns a new Objc provider which includes transitive Objc dependencies."""
-    objc_provider_fields["providers"] = [dep[apple_common.Objc] for dep in ctx.attr.deps]
+    objc_provider_fields["providers"] = [
+        dep[apple_common.Objc]
+        for dep in ctx.attr.deps
+    ] + additional_objc_infos
     return apple_common.new_objc_provider(**objc_provider_fields)
 
-def _cc_info_with_dependencies(ctx, header_imports):
+def _cc_info_with_dependencies(ctx, header_imports, additional_cc_infos = []):
     """Returns a new CcInfo which includes transitive Cc dependencies."""
     cc_info = CcInfo(
         compilation_context = cc_common.create_compilation_context(
@@ -189,7 +192,7 @@ def _cc_info_with_dependencies(ctx, header_imports):
     )
     dep_cc_infos = [dep[CcInfo] for dep in ctx.attr.deps]
     return cc_common.merge_cc_infos(
-        cc_infos = [cc_info] + dep_cc_infos,
+        cc_infos = [cc_info] + dep_cc_infos + additional_cc_infos,
     )
 
 def _transitive_framework_imports(deps):
@@ -415,18 +418,33 @@ def _apple_static_framework_import_impl(ctx):
         if _is_swiftmodule(header.basename)
     ]
 
+    additional_objc_infos = []
+    additional_cc_infos = []
+
     if swiftmodule_imports:
         toolchain = ctx.attr._toolchain[SwiftToolchainInfo]
         providers.append(SwiftUsageInfo(toolchain = toolchain))
 
+        # The Swift toolchain propagates Swift-specific linker flags (e.g.,
+        # library/framework search paths) as an implicit dependency. In the
+        # rare case that a binary has a Swift framework import dependency but
+        # no other Swift dependencies, make sure we pick those up so that it
+        # links to the standard libraries correctly.
+        additional_objc_infos.extend(toolchain.implicit_deps_providers.objc_infos)
+        additional_cc_infos.extend(toolchain.implicit_deps_providers.cc_infos)
+
         if _is_debugging(ctx):
             cpu = ctx.fragments.apple.single_arch_cpu
             swiftmodule = _swiftmodule_for_cpu(swiftmodule_imports, cpu)
             if swiftmodule:
                 objc_provider_fields.update(_ensure_swiftmodule_is_embedded(swiftmodule))
 
-    providers.append(_objc_provider_with_dependencies(ctx, objc_provider_fields))
-    providers.append(_cc_info_with_dependencies(ctx, header_imports))
+    providers.append(
+        _objc_provider_with_dependencies(ctx, objc_provider_fields, additional_objc_infos),
+    )
+    providers.append(
+        _cc_info_with_dependencies(ctx, header_imports, additional_cc_infos),
+    )
 
     # For now, Swift interop is restricted only to a Clang module map inside
     # the framework.

apple/internal/aspects/swift_dynamic_framework_aspect.bzl

@@ -82,11 +82,8 @@ framework module {module_name} {{
 def _swift_dynamic_framework_aspect_impl(target, ctx):
     """Aspect implementation for Swift dynamic framework support."""
 
-    if not hasattr(ctx.rule.attr, "deps"):
-        return []
-
-    swiftdeps = [x for x in ctx.rule.attr.deps if SwiftInfo in x]
-    ccinfos = [x for x in ctx.rule.attr.deps if CcInfo in x]
+    swiftdeps = [x for x in [target] if SwiftInfo in x]
+    ccinfos = [x for x in [target] if CcInfo in x]
 
     # If there are no Swift dependencies, return nothing.
     if not swiftdeps:

apple/internal/binary_support.bzl

@@ -18,61 +18,20 @@ load(
     "@build_bazel_rules_apple//apple/internal:entitlement_rules.bzl",
     "entitlements",
 )
-load(
-    "@build_bazel_rules_apple//apple/internal:swift_support.bzl",
-    "swift_runtime_linkopts",
-)
 
-def _create_swift_runtime_linkopts_target(
-        name,
-        deps,
-        is_static,
-        is_test,
-        tags,
-        testonly):
-    """Creates a build target to propagate Swift runtime linker flags.
-
-    Args:
-      name: The name of the base target.
-      deps: The list of dependencies of the base target.
-      is_static: True to use the static Swift runtime, or False to use the
-          dynamic Swift runtime.
-      is_test: True to make sure test specific linkopts are propagated.
-      tags: Tags to add to the created targets.
-      testonly: Whether the target should be testonly.
-
-    Returns:
-      A build label that can be added to the deps of the binary target.
-    """
-    swift_runtime_linkopts_name = name + ".swift_runtime_linkopts"
-    swift_runtime_linkopts(
-        name = swift_runtime_linkopts_name,
-        is_static = is_static,
-        is_test = is_test,
-        testonly = testonly,
-        tags = tags,
-        deps = deps,
-    )
-    return ":" + swift_runtime_linkopts_name
-
-def _add_entitlements_and_swift_linkopts(
+def _add_entitlements(
         name,
         platform_type,
         product_type,
         include_entitlements = True,
         is_stub = False,
-        link_swift_statically = False,
-        is_test = False,
         **kwargs):
-    """Adds entitlements and Swift linkopts targets for a bundle target.
+    """Adds entitlements targets for a bundle target.
 
     This function creates an entitlements target to ensure that a binary
     created using the `link_multi_arch_binary` API or by copying a stub
     executable gets signed appropriately.
 
-    Similarly, for bundles with user-provided binaries, this function also
-    adds any Swift linkopts that are necessary for it to link correctly.
-
     Args:
       name: The name of the bundle target, from which the targets' names
           will be derived.
@@ -82,9 +41,6 @@ def _add_entitlements_and_swift_linkopts(
           Defaults to True.
       is_stub: True/False, indicates whether the function is being called for a bundle that uses a
           stub executable.
-      link_swift_statically: True/False, indicates whether the static versions of the Swift standard
-          libraries should be used during linking. Only used if include_swift_linkopts is True.
-      is_test: True/False, indicates if test specific linker flags should be propagated.
       **kwargs: The arguments that were passed into the top-level macro.
 
     Returns:
@@ -119,29 +75,13 @@ def _add_entitlements_and_swift_linkopts(
             # propagate linkopts.
             additional_deps.append(":{}".format(entitlements_name))
 
-    deps = bundling_args.get("deps", [])
-
-    if not is_stub:
-        # Propagate the linker flags that dynamically link the Swift runtime, if Swift was used. If
-        # it wasn't, this target propagates no linkopts.
-        additional_deps.append(
-            _create_swift_runtime_linkopts_target(
-                name,
-                deps,
-                link_swift_statically,
-                bool(is_test or testonly),
-                tags = tags,
-                testonly = testonly,
-            ),
-        )
-
-    all_deps = deps + additional_deps
+    all_deps = bundling_args.get("deps", []) + additional_deps
     if all_deps:
         bundling_args["deps"] = all_deps
 
     return bundling_args
 
 # Define the loadable module that lists the exported symbols in this file.
 binary_support = struct(
-    add_entitlements_and_swift_linkopts = _add_entitlements_and_swift_linkopts,
+    add_entitlements = _add_entitlements,
 )

apple/internal/ios_rules.bzl

@@ -1013,17 +1013,16 @@ def _ios_extension_impl(ctx):
 def _ios_dynamic_framework_impl(ctx):
     """Experimental implementation of ios_dynamic_framework."""
 
-    # This rule should only have one swift_library dependency. This means len(ctx.attr.deps) should be 2
-    # because of the swift_runtime_linkopts dep that comes with the swift_libray
+    # This rule should only have one swift_library dependency. This means len(ctx.attr.deps) should be 1
     swiftdeps = [x for x in ctx.attr.deps if SwiftInfo in x]
-    if len(swiftdeps) != 1 or len(ctx.attr.deps) > 2:
+    if len(swiftdeps) != 1 or len(ctx.attr.deps) > 1:
         fail(
             """\
     error: Swift dynamic frameworks expect a single swift_library dependency.
     """,
         )
 
-    binary_target = [deps for deps in ctx.attr.deps if deps.label.name.endswith("swift_runtime_linkopts")][0]
+    binary_target = ctx.attr.deps[0]
     extra_linkopts = []
     if ctx.attr.extension_safe:
         extra_linkopts.append("-fapplication-extension")

apple/internal/swift_support.bzl

@@ -17,8 +17,6 @@
 load(
     "@build_bazel_rules_swift//swift:swift.bzl",
     "SwiftUsageInfo",
-    "swift_common",
-    "swift_usage_aspect",
 )
 
 def _swift_usage_info(targets):
@@ -56,48 +54,6 @@ def _uses_swift(targets):
     """
     return (_swift_usage_info(targets) != None)
 
-def _swift_runtime_linkopts_impl(ctx):
-    """Implementation of the internal `swift_runtime_linkopts` rule.
-
-    This rule is an internal implementation detail and should not be used directly
-    by clients. It examines the dependencies of the target to determine if Swift
-    was used and, if so, propagates additional linker options to have the runtime
-    either dynamically or statically linked.
-
-    Args:
-      ctx: The rule context.
-
-    Returns:
-      A `struct` containing the `objc` provider that should be propagated to a
-      binary to dynamically or statically link the Swift runtime.
-    """
-    linkopts = []
-    swift_usage_info = _swift_usage_info(ctx.attr.deps)
-    if swift_usage_info:
-        linkopts.extend(swift_common.swift_runtime_linkopts(
-            is_static = ctx.attr.is_static,
-            is_test = ctx.attr.is_test,
-            toolchain = swift_usage_info.toolchain,
-        ))
-
-    if linkopts:
-        return [apple_common.new_objc_provider(linkopt = depset(linkopts, order = "topological"))]
-    else:
-        return [apple_common.new_objc_provider()]
-
-swift_runtime_linkopts = rule(
-    _swift_runtime_linkopts_impl,
-    attrs = {
-        "is_static": attr.bool(mandatory = True),
-        "is_test": attr.bool(mandatory = True),
-        "deps": attr.label_list(
-            aspects = [swift_usage_aspect],
-            mandatory = True,
-        ),
-    },
-    fragments = ["apple", "objc"],
-)
-
 # Define the loadable module that lists the exported symbols in this file.
 swift_support = struct(
     swift_usage_info = _swift_usage_info,

apple/internal/testing/apple_test_assembler.bzl

@@ -98,12 +98,11 @@ def _assemble(name, bundle_rule, test_rule, runner = None, runners = None, **kwa
     if "bundle_name" in kwargs:
         fail("bundle_name is not supported in test rules.")
 
-    bundling_args = binary_support.add_entitlements_and_swift_linkopts(
+    bundling_args = binary_support.add_entitlements(
         test_bundle_name,
         bundle_name = name,
         platform_type = str(apple_common.platform_type.ios),
         product_type = apple_product_type.unit_test_bundle,
-        is_test = True,
         include_entitlements = False,
         testonly = True,
         **bundle_attrs

apple/internal/tvos_rules.bzl

@@ -302,17 +302,16 @@ def _tvos_application_impl(ctx):
 def _tvos_dynamic_framework_impl(ctx):
     """Experimental implementation of tvos_dynamic_framework."""
 
-    # This rule should only have one swift_library dependency. This means len(ctx.attr.deps) should be 2
-    # because of the swift_runtime_linkopts dep that comes with the swift_libray
+    # This rule should only have one swift_library dependency. This means len(ctx.attr.deps) should be 1
     swiftdeps = [x for x in ctx.attr.deps if SwiftInfo in x]
-    if len(swiftdeps) != 1 or len(ctx.attr.deps) > 2:
+    if len(swiftdeps) != 1 or len(ctx.attr.deps) > 1:
         fail(
             """\
     error: Swift dynamic frameworks expect a single swift_library dependency.
     """,
         )
 
-    binary_target = [deps for deps in ctx.attr.deps if deps.label.name.endswith("swift_runtime_linkopts")][0]
+    binary_target = ctx.attr.deps[0]
     link_result = linking_support.register_linking_action(
         ctx,
         stamp = ctx.attr.stamp,

apple/internal/watchos_rules.bzl

@@ -94,17 +94,16 @@ load(
 def _watchos_dynamic_framework_impl(ctx):
     """Experimental implementation of watchos_dynamic_framework."""
 
-    # This rule should only have one swift_library dependency. This means len(ctx.attr.deps) should be 2
-    # because of the swift_runtime_linkopts dep that comes with the swift_libray
+    # This rule should only have one swift_library dependency. This means len(ctx.attr.deps) should be 1
     swiftdeps = [x for x in ctx.attr.deps if SwiftInfo in x]
-    if len(swiftdeps) != 1 or len(ctx.attr.deps) > 2:
+    if len(swiftdeps) != 1 or len(ctx.attr.deps) > 1:
         fail(
             """\
     error: Swift dynamic frameworks expect a single swift_library dependency.
     """,
         )
 
-    binary_target = [deps for deps in ctx.attr.deps if deps.label.name.endswith("swift_runtime_linkopts")][0]
+    binary_target = ctx.attr.deps[0]
     extra_linkopts = []
     if ctx.attr.extension_safe:
         extra_linkopts.append("-fapplication-extension")