[Index] Force indexing from the swiftinterfaces of system modules

Use setIgnoreAdjacentModules before indexing any resilient system module
to force indexing to read only from resilient modules.

rdar://100644036

Author: xymus

lib/Index/IndexRecord.cpp

@@ -495,6 +495,22 @@ emitDataForSwiftSerializedModule(ModuleDecl *module,
                                  IndexUnitWriter &parentUnitWriter,
                                  const PathRemapper &pathRemapper,
                                  SourceFile *initialFile) {
+  // Reload resilient modules from swiftinterface to avoid indexing
+  // internal details.
+  if (module->getResilienceStrategy() == ResilienceStrategy::Resilient) {
+    module->getASTContext().setIgnoreAdjacentModules(true);
+
+    ImportPath::Module::Builder builder(module->getName());
+    auto reloadedModule = module->getASTContext().getModule(builder.get());
+
+    if (reloadedModule) {
+      module = reloadedModule;
+    } else {
+      // If we can't rebuild from the swiftinterface, don't index this module.
+      return true;
+    }
+  }
+
   StringRef filename = module->getModuleFilename();
   std::string moduleName = module->getNameStr().str();
 

test/Index/index_system_modules_swiftinterfaces.swift

@@ -0,0 +1,79 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/modulecache)
+// RUN: split-file %s %t
+
+/// Setup the SDK composed of SecretModule and SystemModule
+// RUN: %empty-directory(%t/SDK)
+// RUN: mkdir -p %t/SDK/Frameworks/SecretModule.framework/Modules/SecretModule.swiftmodule
+// RUN: %target-swift-frontend -emit-module -module-name SecretModule \
+// RUN:     -swift-version 5 -enable-library-evolution -parse-stdlib \
+// RUN:     -o %t/SDK/Frameworks/SecretModule.framework/Modules/SecretModule.swiftmodule/%module-target-triple.swiftmodule \
+// RUN:     -emit-module-interface-path %t/SDK/Frameworks/SecretModule.framework/Modules/SecretModule.swiftmodule/%module-target-triple.swiftinterface \
+// RUN:     %t/SecretModule.swift
+// RUN: mkdir -p %t/SDK/Frameworks/SystemModule.framework/Modules/SystemModule.swiftmodule
+// RUN: %target-swift-frontend -emit-module -module-name SystemModule \
+// RUN:     -swift-version 5 -enable-library-evolution -parse-stdlib \
+// RUN:     -o %t/SDK/Frameworks/SystemModule.framework/Modules/SystemModule.swiftmodule/%module-target-triple.swiftmodule \
+// RUN:     -emit-module-interface-path %t/SDK/Frameworks/SystemModule.framework/Modules/SystemModule.swiftmodule/%module-target-triple.swiftinterface \
+// RUN:     -Fsystem %t/SDK/Frameworks \
+// RUN:     %t/SystemModule.swift
+
+/// Index a client of SystemModule reading from the swiftinterface.
+/// Because of disable-deserialization-recovery and leakyFunc, reading from
+/// the swiftmodule would crash.
+// RUN: %empty-directory(%t/idx)
+// RUN: %target-swift-frontend -typecheck -parse-stdlib -swift-version 5 \
+// RUN:     -index-system-modules \
+// RUN:     -index-store-path %t/idx \
+// RUN:     -index-ignore-stdlib \
+// RUN:     -sdk %t/SDK \
+// RUN:     -Fsystem %t/SDK/Frameworks \
+// RUN:     -module-cache-path %t/modulecache \
+// RUN:     %t/Client.swift -disable-deserialization-recovery
+
+/// The index should have the public API of SystemModule
+// RUN: c-index-test core -print-unit %t/idx | %FileCheck -check-prefix=UNIT %s
+// UNIT: Unit | system | SystemModule |
+// UNIT: Record | system | SystemModule |
+// RUN: c-index-test core -print-record %t/idx | %FileCheck -check-prefix=RECORD %s
+// RECORD: function/Swift | systemFunc()
+
+/// Index a client reading from a broken swiftinterface
+// RUN: %empty-directory(%t/idx)
+// RUN: %empty-directory(%t/modulecache)
+// RUN: echo "breaking_the_swifinterface" >> %t/SDK/Frameworks/SystemModule.framework/Modules/SystemModule.swiftmodule/%module-target-triple.swiftinterface
+// RUN: %target-swift-frontend -typecheck -parse-stdlib \
+// RUN:     -index-system-modules \
+// RUN:     -index-store-path %t/idx \
+// RUN:     -index-ignore-stdlib \
+// RUN:     -sdk %t/SDK \
+// RUN:     -Fsystem %t/SDK/Frameworks \
+// RUN:     -module-cache-path %t/modulecache \
+// RUN:     %t/Client.swift \
+// RUN:     2>&1 | %FileCheck -check-prefix=BROKEN-BUILD --allow-empty %s
+
+/// We don't expect so see the swiftinterface error for indexing
+// BROKEN-BUILD-NOT: error
+// BROKEN-BUILD-NOT: breaking_the_swifinterface
+
+/// We don't expect SystemModule to be indexed with a broken swiftinterface
+// RUN: c-index-test core -print-unit %t/idx | %FileCheck -check-prefix=BROKEN-UNIT %s
+// BROKEN-UNIT: Unit | system | SystemModule |
+// BROKEN-UNIT-NOT: Record | system | SystemModule |
+// RUN: c-index-test core -print-record %t/idx | %FileCheck -check-prefix=BROKEN-RECORD %s
+// BROKEN-RECORD-NOT: function/Swift | systemFunc()
+
+//--- SecretModule.swift
+public struct SecretType {}
+
+//--- SystemModule.swift
+// Use this dependency to hit an easy deserialization failure when recovery is disabled.
+@_implementationOnly import SecretModule
+
+public func systemFunc() { }
+func leakyFunc(_ a: SecretType) { }
+
+//--- Client.swift
+import SystemModule
+
+public func clientFunc() {}