[Module] Use stricter module hash

lib/Frontend/ModuleInterfaceLoader.cpp

@@ -2071,8 +2071,24 @@ StringRef InterfaceSubContextDelegateImpl::computeCachedOutputPath(
 std::string
 InterfaceSubContextDelegateImpl::getCacheHash(StringRef useInterfacePath,
                                               StringRef sdkPath) {
-  auto normalizedTargetTriple =
-      getTargetSpecificModuleTriple(genericSubInvocation.getLangOptions().Target);
+  // When doing dependency scanning for explicit module, use strict context hash
+  // to ensure sound module hash.
+  bool useStrictCacheHash =
+      genericSubInvocation.getFrontendOptions().RequestedAction ==
+      FrontendOptions::ActionType::ScanDependencies;
+
+  // Include the normalized target triple when not using strict hash.
+  // Otherwise, use the full target to ensure soundness of the hash. In
+  // practice, .swiftinterface files will be in target-specific subdirectories
+  // and would have target-specific pieces #if'd out. However, it doesn't hurt
+  // to include it, and it guards against mistakenly reusing cached modules
+  // across targets. Note that this normalization explicitly doesn't include the
+  // minimum deployment target (e.g. the '12.0' in 'ios12.0').
+  auto targetToHash = useStrictCacheHash
+                          ? genericSubInvocation.getLangOptions().Target
+                          : getTargetSpecificModuleTriple(
+                                genericSubInvocation.getLangOptions().Target);
+
   std::string sdkBuildVersion = getSDKBuildVersion(sdkPath);
   const auto ExtraArgs = genericSubInvocation.getClangImporterOptions()
                              .getReducedExtraArgsForSwiftModuleDependency();
@@ -2089,13 +2105,8 @@ InterfaceSubContextDelegateImpl::getCacheHash(StringRef useInterfacePath,
       // anyways.
       useInterfacePath,
 
-      // Include the normalized target triple. In practice, .swiftinterface
-      // files will be in target-specific subdirectories and would have
-      // target-specific pieces #if'd out. However, it doesn't hurt to include
-      // it, and it guards against mistakenly reusing cached modules across
-      // targets. Note that this normalization explicitly doesn't include the
-      // minimum deployment target (e.g. the '12.0' in 'ios12.0').
-      normalizedTargetTriple.str(),
+      // The target triple to hash.
+      targetToHash.str(),
 
       // The SDK path is going to affect how this module is imported, so
       // include it.
@@ -2121,6 +2132,10 @@ InterfaceSubContextDelegateImpl::getCacheHash(StringRef useInterfacePath,
       // module.
       llvm::hash_combine_range(ExtraArgs.begin(), ExtraArgs.end()),
 
+      /// Application extension.
+      unsigned(
+          genericSubInvocation.getLangOptions().EnableAppExtensionRestrictions),
+
       // Whether or not OSSA modules are enabled.
       //
       // If OSSA modules are enabled, we use a separate namespace of modules to

test/ScanDependencies/module_hash.swift

@@ -14,7 +14,7 @@
 // RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -O \
 // RUN:   -o %t/deps-3.json -Xcc -fapplication-extension -I %t/include
 
-/// Check module hash for the swiftmodule. 1 and 2 should match, but not 3.
+/// Check module hash for the swiftmodule. They should all not match.
 // RUN: %{python} %S/../CAS/Inputs/SwiftDepsExtractor.py %t/deps-1.json Library modulePath > %t/path-1
 // RUN: %{python} %S/../CAS/Inputs/SwiftDepsExtractor.py %t/deps-2.json Library modulePath > %t/path-2
 // RUN: %{python} %S/../CAS/Inputs/SwiftDepsExtractor.py %t/deps-3.json Library modulePath > %t/path-3

test/ScanDependencies/module_hash_macos.swift

@@ -0,0 +1,47 @@
+// REQUIRES: OS=macosx, objc_interop
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+/// Different version should not match.
+// RUN: %target-swift-frontend -target %module-target-triple -scan-dependencies -module-name Test %t/main.swift -module-cache-path %t/clang-module-cache \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -O \
+// RUN:   -o %t/deps-now.json -I %t/include
+// RUN: %target-swift-frontend -target %module-target-future -scan-dependencies -module-name Test %t/main.swift -module-cache-path %t/clang-module-cache \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -O \
+// RUN:   -o %t/deps-future.json -I %t/include
+// RUN: %{python} %S/../CAS/Inputs/SwiftDepsExtractor.py %t/deps-now.json Library modulePath > %t/path-now
+// RUN: %{python} %S/../CAS/Inputs/SwiftDepsExtractor.py %t/deps-future.json Library modulePath > %t/path-future
+// RUN: not diff %t/path-now %t/path-future
+
+/// Application extension should not match.
+// RUN: %target-swift-frontend -scan-dependencies -module-name Test %t/main.swift -module-cache-path %t/clang-module-cache \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -O \
+// RUN:   -o %t/deps.json -I %t/include
+// RUN: %target-swift-frontend -scan-dependencies -module-name Test %t/main.swift -module-cache-path %t/clang-module-cache \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -O \
+// RUN:   -o %t/deps-ae.json -I %t/include -application-extension
+// RUN: %{python} %S/../CAS/Inputs/SwiftDepsExtractor.py %t/deps.json Library modulePath > %t/path
+// RUN: %{python} %S/../CAS/Inputs/SwiftDepsExtractor.py %t/deps-ae.json Library modulePath > %t/path-ae
+// RUN: not diff %t/path %t/path-ae
+
+//--- main.swift
+import Library
+
+//--- include/Library.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name Library -O -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -user-module-version 1.0
+import Swift
+@_exported import A
+@inlinable
+public func test() {
+    foo()
+}
+
+//--- include/a.h
+void foo(void);
+
+//--- include/module.modulemap
+module A {
+  header "a.h"
+  export *
+}