[Dependency Scanning] Respect the Language Option for cross-import overlay enablement

Author: artemcm

lib/DependencyScan/ModuleDependencyScanner.cpp

@@ -327,9 +327,10 @@ ModuleDependencyScanner::getModuleDependencies(ModuleDependencyID moduleID,
   }
 
   // Resolve cross-import overlays.
-  discoverCrossImportOverlayDependencies(
-      moduleID.ModuleName, allModules.getArrayRef().slice(1), cache,
-      [&](ModuleDependencyID id) { allModules.insert(id); });
+  if (ScanCompilerInvocation.getLangOptions().EnableCrossImportOverlays)
+    discoverCrossImportOverlayDependencies(
+        moduleID.ModuleName, allModules.getArrayRef().slice(1), cache,
+        [&](ModuleDependencyID id) { allModules.insert(id); });
 
   return allModules.takeVector();
 }

test/ScanDependencies/module_deps_cross_import_overlay.swift

@@ -1,11 +1,11 @@
 // RUN: %empty-directory(%t)
 // RUN: mkdir -p %t/clang-module-cache
-// RUN: %target-swift-frontend -scan-dependencies -module-load-mode prefer-interface -module-cache-path %t/clang-module-cache %s -o %t/deps.json -I %S/Inputs/CHeaders -I %S/Inputs/Swift -I %S/Inputs/CHeaders/ExtraCModules -emit-dependencies -emit-dependencies-path %t/deps.d -import-objc-header %S/Inputs/CHeaders/Bridging.h -swift-version 4 -module-name CrossImportTestModule
+// RUN: %target-swift-frontend -scan-dependencies -module-load-mode prefer-interface -module-cache-path %t/clang-module-cache %s -o %t/deps.json -I %S/Inputs/CHeaders -I %S/Inputs/Swift -I %S/Inputs/CHeaders/ExtraCModules -emit-dependencies -emit-dependencies-path %t/deps.d -import-objc-header %S/Inputs/CHeaders/Bridging.h -swift-version 4 -module-name CrossImportTestModule -enable-cross-import-overlays
 // Check the contents of the JSON output
 // RUN: %validate-json %t/deps.json | %FileCheck %s
 
 // Ensure that round-trip serialization does not affect result
-// RUN: %target-swift-frontend -scan-dependencies -module-load-mode prefer-interface -test-dependency-scan-cache-serialization -module-cache-path %t/clang-module-cache %s -o %t/deps.json -I %S/Inputs/CHeaders -I %S/Inputs/Swift -I %S/Inputs/CHeaders/ExtraCModules -emit-dependencies -emit-dependencies-path %t/deps.d -import-objc-header %S/Inputs/CHeaders/Bridging.h -swift-version 4 -module-name CrossImportTestModule
+// RUN: %target-swift-frontend -scan-dependencies -module-load-mode prefer-interface -test-dependency-scan-cache-serialization -module-cache-path %t/clang-module-cache %s -o %t/deps.json -I %S/Inputs/CHeaders -I %S/Inputs/Swift -I %S/Inputs/CHeaders/ExtraCModules -emit-dependencies -emit-dependencies-path %t/deps.d -import-objc-header %S/Inputs/CHeaders/Bridging.h -swift-version 4 -module-name CrossImportTestModule -enable-cross-import-overlays
 // RUN: %validate-json %t/deps.json | %FileCheck %s
 
 // REQUIRES: executable_test

test/ScanDependencies/module_deps_disable_cross_import_overlays.swift

@@ -0,0 +1,28 @@
+// RUN: %empty-directory(%t)
+// RUN: mkdir -p %t/clang-module-cache
+// RUN: %target-swift-frontend -scan-dependencies -module-load-mode prefer-interface -module-cache-path %t/clang-module-cache %s -o %t/deps.json -I %S/Inputs/CHeaders -I %S/Inputs/Swift -I %S/Inputs/CHeaders/ExtraCModules -emit-dependencies -emit-dependencies-path %t/deps.d -import-objc-header %S/Inputs/CHeaders/Bridging.h -module-name CrossImportTestModule -disable-cross-import-overlays
+
+// Check the contents of the JSON output
+// RUN: %validate-json %t/deps.json | %FileCheck %s
+
+// REQUIRES: executable_test
+// REQUIRES: objc_interop
+
+@_exported import CrossImportTestModule
+import EWrapper
+import SubEWrapper
+
+// CHECK:  "directDependencies": [
+// CHECK-DAG:   "swift": "EWrapper"
+// CHECK-DAG:   "swift": "F"
+// CHECK-DAG:   "swift": "SubEWrapper"
+// CHECK-DAG:   "swift": "Swift"
+// CHECK-DAG:   "swift": "SwiftOnoneSupport"
+// CHECK-DAG:   "swift": "_Concurrency"
+// CHECK-DAG:   "swift": "_StringProcessing"
+// CHECK-DAG:   "clang": "_SwiftConcurrencyShims"
+// CHECK-DAG:   "clang": "CrossImportTestModule"
+
+// Ensure the cross-import overlay is not detected with -disable-cross-import-overlays
+// CHECK-NOT:   "swift": "_cross_import_E"
+