Merge pull request #84443 from artemcm/RestrictEmbeddedToBinarySwift

[Dependency Scanning] Avoid querying Swift Overlay for underlying module

Author: artemcm

lib/DependencyScan/ModuleDependencyScanner.cpp

@@ -1456,7 +1456,7 @@ void ModuleDependencyScanner::resolveSwiftOverlayDependenciesForModule(
 
   // A scanning task to query a Swift module by-name. If the module already
   // exists in the cache, do nothing and return.
-  auto scanForSwiftDependency = [this, &cache, &lookupResultLock,
+  auto scanForSwiftDependency = [this, &moduleID, &cache, &lookupResultLock,
                                  &swiftOverlayLookupResult](
                                     Identifier moduleIdentifier) {
     auto moduleName = moduleIdentifier.str();
@@ -1467,6 +1467,13 @@ void ModuleDependencyScanner::resolveSwiftOverlayDependenciesForModule(
         return;
     }
 
+    // Avoid Swift overlay lookup for the underlying clang module of a known
+    // Swift module. i.e. When computing set of Swift Overlay dependencies
+    // for module 'A', which depends on a Clang module 'A', ensure we don't
+    // lookup Swift module 'A' itself here.
+    if (moduleName == moduleID.ModuleName)
+      return;
+
     auto moduleDependencies = withDependencyScanningWorker(
         [moduleIdentifier](ModuleDependencyScanningWorker *ScanningWorker) {
           return ScanningWorker->scanFilesystemForSwiftModuleDependency(

lib/Frontend/CompilerInvocation.cpp

@@ -4171,6 +4171,7 @@ bool CompilerInvocation::parseArgs(
     IRGenOpts.ReflectionMetadata = ReflectionMetadataMode::None;
     IRGenOpts.EnableReflectionNames = false;
     FrontendOpts.DisableBuildingInterface = true;
+    SearchPathOpts.ModuleLoadMode = ModuleLoadingMode::OnlySerialized;
     TypeCheckerOpts.SkipFunctionBodies = FunctionBodySkipping::None;
     SILOpts.SkipFunctionBodies = FunctionBodySkipping::None;
     SILOpts.CMOMode = CrossModuleOptimizationMode::Everything;

test/ScanDependencies/embedded_no_textual.swift

@@ -0,0 +1,18 @@
+// REQUIRES: swift_feature_Embedded
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -emit-module %t/Foo.swift -emit-module-path %t/Foo.swiftmodule/%target-swiftmodule-name -module-name Foo -emit-module-interface-path %t/Foo.swiftmodule/%target-swiftinterface-name -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib -enable-library-evolution
+
+// RUN: %target-swift-frontend -scan-dependencies \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib \
+// RUN:   %t/main.swift -I %t -enable-experimental-feature Embedded -o - | %FileCheck %s --check-prefix=SERIALIZED
+
+// SERIALIZED: "swiftPrebuiltExternal": "Foo"
+
+//--- main.swift
+import Foo
+
+//--- Foo.swift
+public func foo() {}
+