[Serialization] Soft-reject swiftmodules built against a different SDK

Change the way swiftmodules built against a different SDK than their
clients are rejected. This makes them silently ignored when the module
can be rebuilt from their swiftinterface, instead of reporting a hard
error.

rdar://93257769

include/swift/Serialization/Validation.h

@@ -196,13 +196,15 @@ public:
 /// refers directly into this buffer.
 /// \param requiresOSSAModules If true, necessitates the module to be
 /// compiled with -enable-ossa-modules.
+/// \param requiredSDK If not empty, only accept modules built with
+/// a compatible SDK. The StringRef represents the canonical SDK name.
 /// \param[out] extendedInfo If present, will be populated with additional
 /// compilation options serialized into the AST at build time that may be
 /// necessary to load it properly.
 /// \param[out] dependencies If present, will be populated with list of
 /// input files the module depends on, if present in INPUT_BLOCK.
 ValidationInfo validateSerializedAST(
-    StringRef data, bool requiresOSSAModules,
+    StringRef data, bool requiresOSSAModules, StringRef requiredSDK,
     ExtendedValidationInfo *extendedInfo = nullptr,
     SmallVectorImpl<SerializationOptions::FileDependency> *dependencies =
         nullptr);

lib/ASTSectionImporter/ASTSectionImporter.cpp

@@ -36,7 +36,7 @@ bool swift::parseASTSection(MemoryBufferSerializedModuleLoader &Loader,
   // headers. Iterate over all AST modules.
   while (!buf.empty()) {
     auto info = serialization::validateSerializedAST(
-        buf, Loader.isRequiredOSSAModules());
+        buf, Loader.isRequiredOSSAModules(), /*requiredSDK*/StringRef());
 
     assert(info.name.size() < (2 << 10) && "name failed sanity check");
 

lib/Frontend/CompilerInvocation.cpp

@@ -2522,7 +2522,7 @@ serialization::Status
 CompilerInvocation::loadFromSerializedAST(StringRef data) {
   serialization::ExtendedValidationInfo extendedInfo;
   serialization::ValidationInfo info = serialization::validateSerializedAST(
-      data, getSILOptions().EnableOSSAModules, &extendedInfo);
+      data, getSILOptions().EnableOSSAModules, LangOpts.SDKName, &extendedInfo);
 
   if (info.status != serialization::Status::Valid)
     return info.status;
@@ -2558,7 +2558,7 @@ CompilerInvocation::setUpInputForSILTool(
 
   auto result = serialization::validateSerializedAST(
       fileBufOrErr.get()->getBuffer(), getSILOptions().EnableOSSAModules,
-      &extendedInfo);
+      LangOpts.SDKName, &extendedInfo);
   bool hasSerializedAST = result.status == serialization::Status::Valid;
 
   if (hasSerializedAST) {

lib/Frontend/ModuleInterfaceLoader.cpp

@@ -200,9 +200,11 @@ public:
 namespace path = llvm::sys::path;
 
 static bool serializedASTLooksValid(const llvm::MemoryBuffer &buf,
-                                    bool requiresOSSAModules) {
+                                    bool requiresOSSAModules,
+                                    StringRef requiredSDK) {
   auto VI = serialization::validateSerializedAST(buf.getBuffer(),
-                                                 requiresOSSAModules);
+                                                 requiresOSSAModules,
+                                                 requiredSDK);
   return VI.status == serialization::Status::Valid;
 }
 
@@ -500,7 +502,7 @@ class ModuleInterfaceLoaderImpl {
 
     LLVM_DEBUG(llvm::dbgs() << "Validating deps of " << path << "\n");
     auto validationInfo = serialization::validateSerializedAST(
-        buf.getBuffer(), requiresOSSAModules,
+        buf.getBuffer(), requiresOSSAModules, ctx.LangOpts.SDKName,
         /*ExtendedValidationInfo=*/nullptr, &allDeps);
 
     if (validationInfo.status != serialization::Status::Valid) {
@@ -542,7 +544,8 @@ class ModuleInterfaceLoaderImpl {
 
     // First, make sure the underlying module path exists and is valid.
     auto modBuf = fs.getBufferForFile(fwd.underlyingModulePath);
-    if (!modBuf || !serializedASTLooksValid(*modBuf.get(), requiresOSSAModules))
+    if (!modBuf || !serializedASTLooksValid(*modBuf.get(), requiresOSSAModules,
+                                                           ctx.LangOpts.SDKName))
       return false;
 
     // Next, check the dependencies in the forwarding file.

lib/Serialization/ModuleFile.cpp

@@ -156,22 +156,6 @@ Status ModuleFile::associateWithFileContext(FileUnit *file, SourceLoc diagLoc,
       return error(status);
   }
 
-  // The loaded module was built with a compatible SDK if either:
-  // * it was the same SDK
-  // * or one who's name is a prefix of the clients' SDK name. This expects
-  // that a module built with macOS11 can be used with the macOS11.secret SDK.
-  // This is generally the case as SDKs with suffixes are a superset of the
-  // short SDK name equivalent. While this is accepted, this is still not a
-  // recommended configuration and may lead to unreadable swiftmodules.
-  StringRef moduleSDK = Core->SDKName;
-  StringRef clientSDK = ctx.LangOpts.SDKName;
-  if (ctx.SearchPathOpts.EnableSameSDKCheck &&
-      !moduleSDK.empty() && !clientSDK.empty() &&
-      !clientSDK.startswith(moduleSDK)) {
-    status = Status::SDKMismatch;
-    return error(status);
-  }
-
   StringRef SDKPath = ctx.SearchPathOpts.getSDKPath();
   if (SDKPath.empty() ||
       !Core->ModuleInputBuffer->getBufferIdentifier().startswith(SDKPath)) {
@@ -372,7 +356,7 @@ ModuleFile::getModuleName(ASTContext &Ctx, StringRef modulePath,
   bool isFramework = false;
   serialization::ValidationInfo loadInfo = ModuleFileSharedCore::load(
       modulePath.str(), std::move(newBuf), nullptr, nullptr,
-      /*isFramework*/ isFramework, Ctx.SILOpts.EnableOSSAModules,
+      /*isFramework*/ isFramework, Ctx.SILOpts.EnableOSSAModules, Ctx.LangOpts.SDKName,
       Ctx.SearchPathOpts.DeserializedPathRecoverer,
       loadedModuleFile);
   Name = loadedModuleFile->Name.str();

lib/Serialization/ModuleFileSharedCore.cpp

@@ -173,6 +173,7 @@ static ValidationInfo validateControlBlock(
     llvm::BitstreamCursor &cursor, SmallVectorImpl<uint64_t> &scratch,
     std::pair<uint16_t, uint16_t> expectedVersion, bool requiresOSSAModules,
     bool requiresRevisionMatch,
+    StringRef requiredSDK,
     ExtendedValidationInfo *extendedInfo,
     PathObfuscator &pathRecoverer) {
   // The control block is malformed until we've at least read a major version
@@ -307,6 +308,21 @@ static ValidationInfo validateControlBlock(
       break;
     case control_block::SDK_NAME: {
       result.sdkName = blobData;
+
+      // The loaded module was built with a compatible SDK if either:
+      // * it was the same SDK
+      // * or one who's name is a prefix of the clients' SDK name. This expects
+      // that a module built with macOS11 can be used with the macOS11.secret SDK.
+      // This is generally the case as SDKs with suffixes are a superset of the
+      // short SDK name equivalent. While this is accepted, this is still not a
+      // recommended configuration and may lead to unreadable swiftmodules.
+      StringRef moduleSDK = blobData;
+      if (!moduleSDK.empty() && !requiredSDK.empty() &&
+          !requiredSDK.startswith(moduleSDK)) {
+        result.status = Status::SDKMismatch;
+        return result;
+      }
+
       break;
     }
     case control_block::REVISION: {
@@ -443,7 +459,7 @@ bool serialization::isSerializedAST(StringRef data) {
 }
 
 ValidationInfo serialization::validateSerializedAST(
-    StringRef data, bool requiresOSSAModules,
+    StringRef data, bool requiresOSSAModules, StringRef requiredSDK,
     ExtendedValidationInfo *extendedInfo,
     SmallVectorImpl<SerializationOptions::FileDependency> *dependencies) {
   ValidationInfo result;
@@ -487,6 +503,7 @@ ValidationInfo serialization::validateSerializedAST(
           cursor, scratch,
           {SWIFTMODULE_VERSION_MAJOR, SWIFTMODULE_VERSION_MINOR},
           requiresOSSAModules, /*requiresRevisionMatch=*/true,
+          requiredSDK,
           extendedInfo, localObfuscator);
       if (result.status == Status::Malformed)
         return result;
@@ -995,8 +1012,8 @@ bool ModuleFileSharedCore::readModuleDocIfPresent(PathObfuscator &pathRecoverer)
 
       info = validateControlBlock(
           docCursor, scratch, {SWIFTDOC_VERSION_MAJOR, SWIFTDOC_VERSION_MINOR},
-          RequiresOSSAModules, /*requiresRevisionMatch=*/false,
+          RequiresOSSAModules, /*requiresRevisionMatch*/false,
-          /*extendedInfo*/ nullptr, pathRecoverer);
+          /*requiredSDK*/StringRef(), /*extendedInfo*/nullptr, pathRecoverer);
       if (info.status != Status::Valid)
         return false;
       // Check that the swiftdoc is actually for this module.
@@ -1139,9 +1156,8 @@ bool ModuleFileSharedCore::readModuleSourceInfoIfPresent(PathObfuscator &pathRec
       info = validateControlBlock(
           infoCursor, scratch,
           {SWIFTSOURCEINFO_VERSION_MAJOR, SWIFTSOURCEINFO_VERSION_MINOR},
-          RequiresOSSAModules, /*requiresRevisionMatch=*/false,
+          RequiresOSSAModules, /*requiresRevisionMatch*/false,
-          /*extendedInfo*/ nullptr,
+          /*requiredSDK*/StringRef(), /*extendedInfo*/nullptr, pathRecoverer);
-          pathRecoverer);
       if (info.status != Status::Valid)
         return false;
       // Check that the swiftsourceinfo is actually for this module.
@@ -1215,7 +1231,7 @@ ModuleFileSharedCore::ModuleFileSharedCore(
     std::unique_ptr<llvm::MemoryBuffer> moduleInputBuffer,
     std::unique_ptr<llvm::MemoryBuffer> moduleDocInputBuffer,
     std::unique_ptr<llvm::MemoryBuffer> moduleSourceInfoInputBuffer,
-    bool isFramework, bool requiresOSSAModules,
+    bool isFramework, bool requiresOSSAModules, StringRef requiredSDK,
     serialization::ValidationInfo &info, PathObfuscator &pathRecoverer)
     : ModuleInputBuffer(std::move(moduleInputBuffer)),
       ModuleDocInputBuffer(std::move(moduleDocInputBuffer)),
@@ -1267,7 +1283,7 @@ ModuleFileSharedCore::ModuleFileSharedCore(
       info = validateControlBlock(
           cursor, scratch,
           {SWIFTMODULE_VERSION_MAJOR, SWIFTMODULE_VERSION_MINOR},
-          RequiresOSSAModules, /*requiresRevisionMatch=*/true,
+          RequiresOSSAModules, /*requiresRevisionMatch=*/true, requiredSDK,
           &extInfo, pathRecoverer);
       if (info.status != Status::Valid) {
         error(info.status);

lib/Serialization/ModuleFileSharedCore.h

@@ -373,7 +373,7 @@ private:
       std::unique_ptr<llvm::MemoryBuffer> moduleInputBuffer,
       std::unique_ptr<llvm::MemoryBuffer> moduleDocInputBuffer,
       std::unique_ptr<llvm::MemoryBuffer> moduleSourceInfoInputBuffer,
-      bool isFramework, bool requiresOSSAModules,
+      bool isFramework, bool requiresOSSAModules, StringRef requiredSDK,
       serialization::ValidationInfo &info, PathObfuscator &pathRecoverer);
 
   /// Change the status of the current module.
@@ -510,13 +510,13 @@ public:
        std::unique_ptr<llvm::MemoryBuffer> moduleDocInputBuffer,
        std::unique_ptr<llvm::MemoryBuffer> moduleSourceInfoInputBuffer,
        bool isFramework, bool requiresOSSAModules,
-       PathObfuscator &pathRecoverer,
+       StringRef requiredSDK, PathObfuscator &pathRecoverer,
        std::shared_ptr<const ModuleFileSharedCore> &theModule) {
     serialization::ValidationInfo info;
     auto *core = new ModuleFileSharedCore(
         std::move(moduleInputBuffer), std::move(moduleDocInputBuffer),
         std::move(moduleSourceInfoInputBuffer), isFramework,
-        requiresOSSAModules, info, pathRecoverer);
+        requiresOSSAModules, requiredSDK, info, pathRecoverer);
     if (!moduleInterfacePath.empty()) {
       ArrayRef<char> path;
       core->allocateBuffer(path, moduleInterfacePath);

lib/Serialization/SerializedModuleLoader.cpp

@@ -402,7 +402,7 @@ llvm::ErrorOr<ModuleDependencies> SerializedModuleLoaderBase::scanModuleFile(
   bool isFramework = false;
   serialization::ValidationInfo loadInfo = ModuleFileSharedCore::load(
       modulePath.str(), std::move(moduleBuf.get()), nullptr, nullptr,
-      isFramework, isRequiredOSSAModules(),
+      isFramework, isRequiredOSSAModules(), Ctx.LangOpts.SDKName,
       Ctx.SearchPathOpts.DeserializedPathRecoverer,
       loadedModuleFile);
 
@@ -753,7 +753,7 @@ LoadedFile *SerializedModuleLoaderBase::loadAST(
   serialization::ValidationInfo loadInfo = ModuleFileSharedCore::load(
       moduleInterfacePath, std::move(moduleInputBuffer),
       std::move(moduleDocInputBuffer), std::move(moduleSourceInfoInputBuffer),
-      isFramework, isRequiredOSSAModules(),
+      isFramework, isRequiredOSSAModules(), Ctx.LangOpts.SDKName,
       Ctx.SearchPathOpts.DeserializedPathRecoverer,
       loadedModuleFileCore);
   SerializedASTFile *fileUnit = nullptr;
@@ -1176,7 +1176,8 @@ bool SerializedModuleLoaderBase::canImportModule(ImportPath::Module path,
   // format, if present.
   if (currentVersion.empty() && *unusedModuleBuffer) {
     auto metaData = serialization::validateSerializedAST(
-        (*unusedModuleBuffer)->getBuffer(), Ctx.SILOpts.EnableOSSAModules);
+        (*unusedModuleBuffer)->getBuffer(), Ctx.SILOpts.EnableOSSAModules,
+        Ctx.LangOpts.SDKName);
     currentVersion = metaData.userModuleVersion;
   }
 

test/Serialization/restrict-swiftmodule-to-sdk.swift

@@ -20,6 +20,15 @@
 // RUN: not %target-swift-frontend -typecheck %t/Client.swift -swift-version 5 -target-sdk-name C -I %t/build -parse-stdlib -module-cache-path %t/cache 2>&1 | %FileCheck %s -check-prefix=CHECK-C
 // CHECK-C: cannot load module 'Lib' built with SDK 'C.Secret' when using SDK 'C': {{.*}}Lib.swiftmodule
 
+/// Build a resilient Lib against SDK A, and a client against SDK B.
+/// This should succeed after rebuilding from the swiftinterface.
+// RUN: %empty-directory(%t/cache)
+// RUN: %target-swift-frontend -emit-module %t/Lib.swift -swift-version 5 -target-sdk-name A -o %t/build -parse-stdlib -module-cache-path %t/cache \
+// RUN:   -enable-library-evolution -emit-module-interface-path %t/build/Lib.swiftinterface
+// RUN: %target-swift-frontend -typecheck %t/Client.swift -swift-version 5 -target-sdk-name B -I %t/build -parse-stdlib -module-cache-path %t/cache \
+// RUN:   -Rmodule-interface-rebuild 2>&1 | %FileCheck %s -check-prefix=CHECK-AvsB-REBUILD
+// CHECK-AvsB-REBUILD: remark: rebuilding module 'Lib' from interface
+
 // BEGIN Lib.swift
 public func foo() {}
 

tools/lldb-moduleimport-test/lldb-moduleimport-test.cpp

@@ -49,6 +49,7 @@ validateModule(llvm::StringRef data, bool Verbose, bool requiresOSSAModules,
                swift::serialization::ValidationInfo &info,
                swift::serialization::ExtendedValidationInfo &extendedInfo) {
   info = swift::serialization::validateSerializedAST(data, requiresOSSAModules,
+                                                     /*requiredSDK*/StringRef(),
                                                      &extendedInfo);
   if (info.status != swift::serialization::Status::Valid) {
     llvm::outs() << "error: validateSerializedAST() failed\n";

unittests/FrontendTool/ModuleLoadingTests.cpp

@@ -149,7 +149,7 @@ protected:
 
     auto bufData = (*bufOrErr)->getBuffer();
     auto validationInfo = serialization::validateSerializedAST(
-        bufData, silOpts.EnableOSSAModules);
+        bufData, silOpts.EnableOSSAModules, /*requiredSDK*/StringRef());
     ASSERT_EQ(serialization::Status::Valid, validationInfo.status);
     ASSERT_EQ(bufData, moduleBuffer->getBuffer());
   }