Remove the -enable-ossa-modules option.

OSSA modules are enabled by default.
The compiler still accepts this option but it has no effect.

Runtimes/Core/CMakeLists.txt

@@ -194,7 +194,6 @@ add_compile_options(
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-implicit-string-processing-module-import>"
   "$<$<COMPILE_LANGUAGE:Swift>:-no-link-objc-runtime>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -enforce-exclusivity=unchecked>"
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -enable-ossa-modules>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -empty-abi-descriptor>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -target-min-inlining-version -Xfrontend min>"
   "$<$<AND:$<NOT:$<BOOL:${SwiftCore_ENABLE_OBJC_INTEROP}>>,$<COMPILE_LANGUAGE:Swift>>:SHELL:-Xfrontend -disable-objc-interop>"

Runtimes/Overlay/CMakeLists.txt

@@ -71,7 +71,6 @@ add_compile_options(
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-implicit-concurrency-module-import>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -disable-implicit-string-processing-module-import>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -enforce-exclusivity=unchecked>"
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -enable-ossa-modules>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -target-min-inlining-version -Xfrontend min>"
   "$<$<AND:$<BOOL:${${PROJECT_NAME}_ENABLE_LIBRARY_EVOLUTION}>,$<COMPILE_LANGUAGE:Swift>>:-enable-library-evolution>"
   "$<$<AND:$<BOOL:${${PROJECT_NAME}_ENABLE_PRESPECIALIZATION}>,$<COMPILE_LANGUAGE:Swift>>:SHELL:-Xfrontend -prespecialize-generic-metadata>")

Runtimes/Supplemental/Observation/CMakeLists.txt

@@ -81,7 +81,6 @@ add_compile_options(
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature Macros>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-enable-experimental-feature ExtensionMacros>"
   "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -enable-lexical-lifetimes=false>"
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xfrontend -enable-ossa-modules>"
   "$<$<COMPILE_LANGUAGE:Swift>:-warn-implicit-overrides>"
   "$<$<AND:$<BOOL:${${PROJECT_NAME}_ENABLE_LIBRARY_EVOLUTION}>,$<COMPILE_LANGUAGE:Swift>>:-enable-library-evolution>"
   "$<$<AND:$<BOOL:${${PROJECT_NAME}_ENABLE_PRESPECIALIZATION}>,$<COMPILE_LANGUAGE:Swift>>:SHELL:-Xfrontend -prespecialize-generic-metadata>")

include/swift/AST/SILOptions.h

@@ -45,13 +45,12 @@ enum class CopyPropagationOption : uint8_t {
   // Do not add any copy propagation passes.
   Off = 0,
 
-  // Only add the copy propagation passes requested by other flags, currently
+  // Only add the copy propagation passes requested by other flags.
-  // just -enable-ossa-modules.
   RequestedPassesOnly,
 
   // Run copy propagation during optimized builds only.
   //
-  // If a setting, e.g. -enable-ossa-modules, requests to add copy propagation
+  // If a setting, requests to add copy propagation
   // to the performance pipeline, do so.
   Optimizing,
 
@@ -189,11 +188,6 @@ public:
   /// and go from OSSA to non-ownership SIL.
   bool StopOptimizationBeforeLoweringOwnership = false;
 
-  /// Do we always serialize SIL in OSSA form?
-  ///
-  /// If this is disabled we do not serialize in OSSA form when optimizing.
-  bool EnableOSSAModules = true;
-
   /// Allow recompilation of a non-OSSA module to an OSSA module when imported
   /// from another OSSA module.
   bool EnableRecompilationToOSSAModule = false;

include/swift/Frontend/ModuleInterfaceLoader.h

@@ -478,25 +478,6 @@ public:
   ModuleInterfaceLoaderOptions() = default;
 };
 
-/// Strongly typed enum that represents if we require all SILModules to have
-/// OSSA modules emitted. This is implemented by incorporating this bit into the
-/// module cache hash.
-struct RequireOSSAModules_t {
-  enum ValueTy {
-    No = 0,
-    Yes = 1,
-  };
-
-  ValueTy value;
-
-  RequireOSSAModules_t(const SILOptions &opts)
-      : value(opts.EnableOSSAModules ? RequireOSSAModules_t::Yes
-                                     : RequireOSSAModules_t::No) {}
-
-  operator ValueTy() const { return value; }
-  explicit operator bool() const { return bool(value); }
-};
-
 class ModuleInterfaceCheckerImpl: public ModuleInterfaceChecker {
   friend class ModuleInterfaceLoader;
   ASTContext &Ctx;
@@ -504,23 +485,20 @@ class ModuleInterfaceCheckerImpl: public ModuleInterfaceChecker {
   std::string PrebuiltCacheDir;
   std::string BackupInterfaceDir;
   ModuleInterfaceLoaderOptions Opts;
-  RequireOSSAModules_t RequiresOSSAModules;
 
 public:
   explicit ModuleInterfaceCheckerImpl(ASTContext &Ctx, StringRef cacheDir,
                                 StringRef prebuiltCacheDir,
                                 StringRef BackupInterfaceDir,
-                                ModuleInterfaceLoaderOptions opts,
+                                ModuleInterfaceLoaderOptions opts)
-                                RequireOSSAModules_t requiresOSSAModules)
       : Ctx(Ctx), CacheDir(cacheDir), PrebuiltCacheDir(prebuiltCacheDir),
         BackupInterfaceDir(BackupInterfaceDir),
-        Opts(opts), RequiresOSSAModules(requiresOSSAModules) {}
+        Opts(opts) {}
   explicit ModuleInterfaceCheckerImpl(ASTContext &Ctx, StringRef cacheDir,
                                 StringRef prebuiltCacheDir,
-                                ModuleInterfaceLoaderOptions opts,
+                                ModuleInterfaceLoaderOptions opts):
-                                RequireOSSAModules_t requiresOSSAModules):
     ModuleInterfaceCheckerImpl(Ctx, cacheDir, prebuiltCacheDir, StringRef(),
-                               opts, requiresOSSAModules) {}
+                               opts) {}
   std::vector<std::string>
   getCompiledModuleCandidatesForInterface(StringRef moduleName,
                                           StringRef interfacePath) override;
@@ -596,7 +574,6 @@ public:
       ArrayRef<std::pair<std::string, std::string>> replayPrefixMap,
       bool SerializeDependencyHashes, bool TrackSystemDependencies,
       ModuleInterfaceLoaderOptions Opts,
-      RequireOSSAModules_t RequireOSSAModules,
       bool silenceInterfaceDiagnostics);
 
   /// Unconditionally build \p InPath (a swiftinterface file) to \p OutPath (as
@@ -666,8 +643,7 @@ private:
                                      const LangOptions &LangOpts,
                                      const ClangImporterOptions &clangImporterOpts,
                                      const CASOptions &casOpts,
-                                     bool suppressRemarks,
+                                     bool suppressRemarks);
-                                     RequireOSSAModules_t requireOSSAModules);
   bool extractSwiftInterfaceVersionAndArgs(CompilerInvocation &subInvocation,
                                            DiagnosticEngine &subInstanceDiags,
                                            SwiftInterfaceInfo &interfaceInfo,
@@ -684,7 +660,7 @@ public:
       StringRef backupModuleInterfaceDir,
       ArrayRef<std::pair<std::string, std::string>> replayPrefixMap,
       bool serializeDependencyHashes,
-      bool trackSystemDependencies, RequireOSSAModules_t requireOSSAModules);
+      bool trackSystemDependencies);
 
   template<typename ...ArgTypes>
   static InFlightDiagnostic diagnose(StringRef interfacePath,

include/swift/Option/FrontendOptions.td

@@ -1320,8 +1320,7 @@ def disable_ast_verifier : Flag<["-"], "disable-ast-verifier">,
 
 let Flags = [FrontendOption, NoDriverOption, HelpHidden, ModuleInterfaceOptionIgnorable] in {
   def enable_ossa_modules : Flag<["-"], "enable-ossa-modules">,
-    HelpText<"Always serialize SIL in ossa form. If this flag is not passed in, "
+    HelpText<"Obsolete. This option is ignored">;
-            "when optimizing ownership will be lowered before serializing SIL">;
 }
 
 def enable_recompilation_to_ossa_module : Flag<["-"], "enable-recompilation-to-ossa-module">,

include/swift/Serialization/SerializedModuleLoader.h

@@ -193,7 +193,6 @@ protected:
   static llvm::ErrorOr<std::vector<ScannerImportStatementInfo>>
   getMatchingPackageOnlyImportsOfModule(Twine modulePath,
                                         bool isFramework,
-                                        bool isRequiredOSSAModules,
                                         StringRef SDKName,
                                         const llvm::Triple &target,
                                         StringRef packageName,
@@ -222,8 +221,6 @@ public:
           std::unique_ptr<llvm::MemoryBuffer> moduleSourceInfoInputBuffer,
           bool isFramework);
 
-  bool isRequiredOSSAModules() const;
-
   /// Check whether the module with a given name can be imported without
   /// importing it.
   ///

include/swift/Serialization/Validation.h

@@ -297,8 +297,6 @@ struct SearchPath {
 ///
 /// \param data A buffer containing the serialized AST. Result information
 /// 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 target The target triple of the current compilation for
@@ -309,7 +307,7 @@ struct SearchPath {
 /// \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,
     StringRef requiredSDK,
     ExtendedValidationInfo *extendedInfo = nullptr,
     SmallVectorImpl<SerializationOptions::FileDependency> *dependencies =

lib/ASTSectionImporter/ASTSectionImporter.cpp

@@ -58,7 +58,7 @@ swift::parseASTSection(MemoryBufferSerializedModuleLoader &Loader,
   // headers. Iterate over all AST modules.
   while (!buf.empty()) {
     auto info = serialization::validateSerializedAST(
-        buf, Loader.isRequiredOSSAModules(),
+        buf,
         /*requiredSDK*/StringRef());
 
     assert(info.name.size() < (2 << 10) && "name failed sanity check");

lib/DependencyScan/ModuleDependencyScanner.cpp

@@ -252,8 +252,8 @@ ModuleDependencyScanningWorker::ModuleDependencyScanningWorker(
       workerCompilerInvocation->getFrontendOptions()
           .SerializeModuleInterfaceDependencyHashes,
       workerCompilerInvocation->getFrontendOptions()
-          .shouldTrackSystemDependencies(),
+          .shouldTrackSystemDependencies()
-      RequireOSSAModules_t(SILOptions));
+      );
 
   auto loader = std::make_unique<PluginLoader>(
       *workerASTContext, /*DepTracker=*/nullptr,

lib/DriverTool/sil_func_extractor_main.cpp

@@ -118,12 +118,6 @@ struct SILFuncExtractorOptions {
                  llvm::cl::init(false),
                  llvm::cl::desc("Do not dump AST."));
 
-  llvm::cl::opt<bool> EnableOSSAModules = llvm::cl::opt<bool>(
-      "enable-ossa-modules", llvm::cl::init(true),
-      llvm::cl::desc("Do we always serialize SIL in OSSA form? If "
-                     "this is disabled we do not serialize in OSSA "
-                     "form when optimizing."));
-
   llvm::cl::opt<llvm::cl::boolOrDefault>
     EnableObjCInterop = llvm::cl::opt<llvm::cl::boolOrDefault>(
       "enable-objc-interop",
@@ -275,7 +269,6 @@ int sil_func_extractor_main(ArrayRef<const char *> argv, void *MainAddr) {
   SILOptions &Opts = Invocation.getSILOptions();
   Opts.EmitVerboseSIL = options.EmitVerboseSIL;
   Opts.EmitSortedSIL = options.EmitSortedSIL;
-  Opts.EnableOSSAModules = options.EnableOSSAModules;
   Opts.StopOptimizationAfterSerialization |= options.EmitSIB;
 
   serialization::ExtendedValidationInfo extendedInfo;
@@ -368,7 +361,7 @@ int sil_func_extractor_main(ArrayRef<const char *> argv, void *MainAddr) {
     serializationOpts.OutputPath = OutputFile;
     serializationOpts.SerializeAllSIL = true;
     serializationOpts.IsSIB = true;
-    serializationOpts.IsOSSA = options.EnableOSSAModules;
+    serializationOpts.IsOSSA = true;
 
     symbolgraphgen::SymbolGraphOptions symbolGraphOpts;
 

lib/DriverTool/sil_opt_main.cpp

@@ -316,12 +316,6 @@ struct SILOptOptions {
   EnableMoveInoutStackProtection = llvm::cl::opt<bool>("enable-move-inout-stack-protector",
                     llvm::cl::desc("Enable the stack protector by moving values to temporaries."));
 
-  llvm::cl::opt<bool> EnableOSSAModules = llvm::cl::opt<bool>(
-      "enable-ossa-modules", llvm::cl::init(true),
-      llvm::cl::desc("Do we always serialize SIL in OSSA form? If "
-                     "this is disabled we do not serialize in OSSA "
-                     "form when optimizing."));
-
   cl::opt<EnforceExclusivityMode>
     EnforceExclusivity = cl::opt<EnforceExclusivityMode>(
     "enforce-exclusivity", cl::desc("Enforce law of exclusivity "
@@ -902,7 +896,6 @@ int sil_opt_main(ArrayRef<const char *> argv, void *MainAddr) {
   SILOpts.EnableThrowsPrediction = options.EnableThrowsPrediction;
   SILOpts.EnableNoReturnCold = options.EnableNoReturnCold;
   SILOpts.IgnoreAlwaysInline = options.IgnoreAlwaysInline;
-  SILOpts.EnableOSSAModules = options.EnableOSSAModules;
   SILOpts.EnableSILOpaqueValues = options.EnableSILOpaqueValues;
   SILOpts.OSSACompleteLifetimes = options.EnableOSSACompleteLifetimes;
   SILOpts.OSSAVerifyComplete = options.EnableOSSAVerifyComplete;
@@ -1088,7 +1081,7 @@ int sil_opt_main(ArrayRef<const char *> argv, void *MainAddr) {
     serializationOpts.OutputPath = OutputFile;
     serializationOpts.SerializeAllSIL = options.EmitSIB;
     serializationOpts.IsSIB = options.EmitSIB;
-    serializationOpts.IsOSSA = SILOpts.EnableOSSAModules;
+    serializationOpts.IsOSSA = true;
 
     symbolgraphgen::SymbolGraphOptions symbolGraphOptions;
 

lib/Frontend/CompilerInvocation.cpp

@@ -3047,7 +3047,6 @@ static bool ParseSILArgs(SILOptions &Opts, ArgList &Args,
         enablePackMetadataStackPromotionFlag.value();
 
   Opts.EnableARCOptimizations &= !Args.hasArg(OPT_disable_arc_opts);
-  Opts.EnableOSSAModules |= Args.hasArg(OPT_enable_ossa_modules);
   Opts.EnableRecompilationToOSSAModule |=
       Args.hasArg(OPT_enable_recompilation_to_ossa_module);
   Opts.EnableOSSAOptimizations &= !Args.hasArg(OPT_disable_ossa_opts);
@@ -4190,8 +4189,6 @@ bool CompilerInvocation::parseArgs(
     SILOpts.CMOMode = CrossModuleOptimizationMode::Everything;
     SILOpts.EmbeddedSwift = true;
     SILOpts.UseAggressiveReg2MemForCodeSize = true;
-    // OSSA modules are required for deinit de-virtualization.
-    SILOpts.EnableOSSAModules = true;
     // -g is promoted to -gdwarf-types in embedded Swift
     if (IRGenOpts.DebugInfoLevel == IRGenDebugInfoLevel::ASTTypes) {
       IRGenOpts.DebugInfoLevel = IRGenDebugInfoLevel::DwarfTypes;
@@ -4244,7 +4241,6 @@ CompilerInvocation::loadFromSerializedAST(StringRef data) {
   serialization::ValidationInfo info =
       serialization::validateSerializedAST(
         data,
-        getSILOptions().EnableOSSAModules,
         LangOpts.SDKName,
         &extendedInfo);
 
@@ -4282,7 +4278,6 @@ CompilerInvocation::setUpInputForSILTool(
 
   auto result = serialization::validateSerializedAST(
       fileBufOrErr.get()->getBuffer(),
-      getSILOptions().EnableOSSAModules,
       LangOpts.SDKName,
       &extendedInfo);
   bool hasSerializedAST = result.status == serialization::Status::Valid;

lib/Frontend/Frontend.cpp

@@ -281,7 +281,7 @@ SerializationOptions CompilerInvocation::computeSerializationOptions(
     serializationOpts.SerializeDebugInfoSIL = true;
   }
 
-  serializationOpts.IsOSSA = getSILOptions().EnableOSSAModules;
+  serializationOpts.IsOSSA = true;
 
   serializationOpts.SkipNonExportableDecls =
       getLangOptions().SkipNonExportableDecls;
@@ -792,8 +792,7 @@ bool CompilerInstance::setUpModuleLoaders() {
     Context->addModuleInterfaceChecker(
         std::make_unique<ModuleInterfaceCheckerImpl>(
             *Context, ModuleCachePathFromInvocation, FEOpts.PrebuiltModuleCachePath,
-            FEOpts.BackupModuleInterfaceDir, LoaderOpts,
+            FEOpts.BackupModuleInterfaceDir, LoaderOpts));
-            RequireOSSAModules_t(Invocation.getSILOptions())));
 
     if (MLM != ModuleLoadingMode::OnlySerialized) {
       // We only need ModuleInterfaceLoader for implicit modules.
@@ -867,8 +866,7 @@ bool CompilerInstance::setUpModuleLoaders() {
   Context->addModuleInterfaceChecker(
       std::make_unique<ModuleInterfaceCheckerImpl>(
           *Context, ModuleCachePath, FEOpts.PrebuiltModuleCachePath,
-          FEOpts.BackupModuleInterfaceDir, LoaderOpts,
+          FEOpts.BackupModuleInterfaceDir, LoaderOpts));
-          RequireOSSAModules_t(Invocation.getSILOptions())));
 
   // Install an explicit module loader if it was created earlier.
   if (ESML) {
@@ -910,8 +908,7 @@ bool CompilerInstance::setUpModuleLoaders() {
         FEOpts.PrebuiltModuleCachePath, FEOpts.BackupModuleInterfaceDir,
         FEOpts.CacheReplayPrefixMap,
         FEOpts.SerializeModuleInterfaceDependencyHashes,
-        FEOpts.shouldTrackSystemDependencies(),
+        FEOpts.shouldTrackSystemDependencies());
-        RequireOSSAModules_t(Invocation.getSILOptions()));
   }
 
   return false;

lib/Frontend/ModuleInterfaceBuilder.cpp

@@ -310,7 +310,7 @@ std::error_code ExplicitModuleInterfaceBuilder::buildSwiftModuleFromInterface(
       return std::make_error_code(std::errc::not_supported);
     SerializationOpts.Dependencies = Deps;
   }
-  SerializationOpts.IsOSSA = SILOpts.EnableOSSAModules;
+  SerializationOpts.IsOSSA = true;
 
   SILMod->setSerializeSILAction([&]() {
     // We don't want to serialize module docs in the cache -- they

lib/Frontend/ModuleInterfaceLoader.cpp

@@ -213,10 +213,8 @@ public:
 namespace path = llvm::sys::path;
 
 static bool serializedASTLooksValid(const llvm::MemoryBuffer &buf,
-                                    bool requiresOSSAModules,
                                     StringRef requiredSDK) {
   auto VI = serialization::validateSerializedAST(buf.getBuffer(),
-                                                 requiresOSSAModules,
                                                  requiredSDK);
   return VI.status == serialization::Status::Valid;
 }
@@ -408,14 +406,11 @@ StringRef getFullDependencyPath(const FileDependency &dep,
 class UpToDateModuleCheker {
   ASTContext &ctx;
   llvm::vfs::FileSystem &fs;
-  RequireOSSAModules_t requiresOSSAModules;
 
 public:
-  UpToDateModuleCheker(ASTContext &ctx,
+  UpToDateModuleCheker(ASTContext &ctx)
-                       RequireOSSAModules_t requiresOSSAModules)
      : ctx(ctx),
-       fs(*ctx.SourceMgr.getFileSystem()),
+       fs(*ctx.SourceMgr.getFileSystem()) {}
-       requiresOSSAModules(requiresOSSAModules) {}
 
   // Check if all the provided file dependencies are up-to-date compared to
   // what's currently on disk.
@@ -460,7 +455,7 @@ public:
 
     LLVM_DEBUG(llvm::dbgs() << "Validating deps of " << path << "\n");
     auto validationInfo = serialization::validateSerializedAST(
-        buf.getBuffer(), requiresOSSAModules,
+        buf.getBuffer(),
         ctx.LangOpts.SDKName, /*ExtendedValidationInfo=*/nullptr, &allDeps);
 
     if (validationInfo.status != serialization::Status::Valid) {
@@ -551,25 +546,22 @@ class ModuleInterfaceLoaderImpl {
   DependencyTracker *const dependencyTracker;
   const ModuleLoadingMode loadMode;
   ModuleInterfaceLoaderOptions Opts;
-  RequireOSSAModules_t requiresOSSAModules;
 
   ModuleInterfaceLoaderImpl(
       ASTContext &ctx, StringRef modulePath, StringRef interfacePath,
       StringRef moduleName, StringRef cacheDir, StringRef prebuiltCacheDir,
       StringRef backupInterfaceDir,
       SourceLoc diagLoc, ModuleInterfaceLoaderOptions Opts,
-      RequireOSSAModules_t requiresOSSAModules,
       DependencyTracker *dependencyTracker = nullptr,
       ModuleLoadingMode loadMode = ModuleLoadingMode::PreferSerialized)
       : ctx(ctx), fs(*ctx.SourceMgr.getFileSystem()), diags(ctx.Diags),
-        upToDateChecker(ctx, requiresOSSAModules),
+        upToDateChecker(ctx),
         modulePath(modulePath), interfacePath(interfacePath),
         moduleName(moduleName),
         prebuiltCacheDir(prebuiltCacheDir),
         backupInterfaceDir(backupInterfaceDir),
         cacheDir(cacheDir), diagnosticLoc(diagLoc),
-        dependencyTracker(dependencyTracker), loadMode(loadMode), Opts(Opts),
+        dependencyTracker(dependencyTracker), loadMode(loadMode), Opts(Opts) {}
-        requiresOSSAModules(requiresOSSAModules) {}
 
   std::string getBackupPublicModuleInterfacePath() {
     return getBackupPublicModuleInterfacePath(ctx.SourceMgr, backupInterfaceDir,
@@ -622,7 +614,6 @@ class ModuleInterfaceLoaderImpl {
       return false;
 
     auto looksValid = serializedASTLooksValid(*modBuf.get(),
-                                              requiresOSSAModules,
                                               ctx.LangOpts.SDKName);
     if (!looksValid)
       return false;
@@ -935,15 +926,7 @@ class ModuleInterfaceLoaderImpl {
                    version::getCurrentCompilerSerializationTag().empty() &&
                    rebuildInfo.getOrInsertCandidateModule(adjacentMod)
                            .serializationStatus !=
-                       serialization::Status::SDKMismatch &&
+                       serialization::Status::SDKMismatch) {
-                   // FIXME (meg-gupta): We need to support recompilation of
-                   // modules in the resource directory if the mismatch is due
-                   // to importing a non-ossa module to an ossa module. This is
-                   // needed during ossa bringup, once -enable-ossa-modules is
-                   // on by default, this can be deleted.
-                   rebuildInfo.getOrInsertCandidateModule(adjacentMod)
-                           .serializationStatus !=
-                       serialization::Status::NotInOSSA) {
           // Special-case here: If we're loading a .swiftmodule from the resource
           // dir adjacent to the compiler, defer to the serialized loader instead
           // of falling back. This is to support local development of Swift,
@@ -1130,8 +1113,7 @@ class ModuleInterfaceLoaderImpl {
         ctx.ClangImporterOpts, ctx.CASOpts, Opts,
         /*buildModuleCacheDirIfAbsent*/ true, cacheDir, prebuiltCacheDir,
         backupInterfaceDir, /*replayPrefixMap=*/{},
-        /*serializeDependencyHashes*/ false, trackSystemDependencies,
+        /*serializeDependencyHashes*/ false, trackSystemDependencies);
-        requiresOSSAModules);
 
     // Compute the output path if we're loading or emitting a cached module.
     SwiftInterfaceModuleOutputPathResolution::ResultTy resolvedOutputPath;
@@ -1375,7 +1357,6 @@ std::error_code ModuleInterfaceLoader::findModuleFilesInDirectory(
       Ctx, ModPath, *InPath, ModuleName, InterfaceChecker.CacheDir,
       InterfaceChecker.PrebuiltCacheDir, InterfaceChecker.BackupInterfaceDir,
       ModuleID.Loc, InterfaceChecker.Opts,
-      InterfaceChecker.RequiresOSSAModules,
       dependencyTracker,
       llvm::is_contained(PreferInterfaceForModules, ModuleName)
           ? ModuleLoadingMode::PreferInterface
@@ -1429,7 +1410,7 @@ ModuleInterfaceCheckerImpl::getCompiledModuleCandidatesForInterface(
 
   ModuleInterfaceLoaderImpl Impl(Ctx, modulePath, interfacePath, moduleName,
                                  CacheDir, PrebuiltCacheDir, BackupInterfaceDir,
-                                 SourceLoc(), Opts, RequiresOSSAModules,
+                                 SourceLoc(), Opts,
                                  nullptr, Ctx.SearchPathOpts.ModuleLoadMode);
   std::vector<std::string> results;
   std::string adjacentMod, prebuiltMod;
@@ -1469,7 +1450,6 @@ bool ModuleInterfaceCheckerImpl::tryEmitForwardingModule(
   ModuleInterfaceLoaderImpl Impl(Ctx, modulePath, interfacePath, moduleName,
                                  CacheDir, PrebuiltCacheDir,
                                  BackupInterfaceDir, SourceLoc(), Opts,
-                                 RequiresOSSAModules,
                                  nullptr,
                                  ModuleLoadingMode::PreferSerialized);
   SmallVector<FileDependency, 16> deps;
@@ -1503,13 +1483,13 @@ bool ModuleInterfaceLoader::buildSwiftModuleFromSwiftInterface(
     ArrayRef<std::pair<std::string, std::string>> replayPrefixMap,
     bool SerializeDependencyHashes, bool TrackSystemDependencies,
     ModuleInterfaceLoaderOptions LoaderOpts,
-    RequireOSSAModules_t RequireOSSAModules, bool silenceInterfaceDiagnostics) {
+    bool silenceInterfaceDiagnostics) {
   InterfaceSubContextDelegateImpl astDelegate(
       SourceMgr, &Diags, SearchPathOpts, LangOpts, ClangOpts, CASOpts,
       LoaderOpts,
       /*CreateCacheDirIfAbsent*/ true, CacheDir, PrebuiltCacheDir,
       BackupInterfaceDir, replayPrefixMap, SerializeDependencyHashes,
-      TrackSystemDependencies, RequireOSSAModules);
+      TrackSystemDependencies);
   ImplicitModuleInterfaceBuilder builder(SourceMgr, &Diags, astDelegate, InPath,
                                          SearchPathOpts.getSDKPath(),
                                          SearchPathOpts.getSysRoot(),
@@ -1635,8 +1615,7 @@ bool ModuleInterfaceLoader::buildExplicitSwiftModuleFromSwiftInterface(
     // up-to-date w.r.t. all of the dependencies it was built with. If so, early
     // exit.
     UpToDateModuleCheker checker(
-        Instance.getASTContext(),
+        Instance.getASTContext());
-        RequireOSSAModules_t(Instance.getSILOptions()));
     ModuleRebuildInfo rebuildInfo;
     SmallVector<FileDependency, 3> allDeps;
     std::unique_ptr<llvm::MemoryBuffer> moduleBuffer;
@@ -1684,7 +1663,7 @@ void InterfaceSubContextDelegateImpl::inheritOptionsForBuildingInterface(
     FrontendOptions::ActionType requestedAction,
     const SearchPathOptions &SearchPathOpts, const LangOptions &LangOpts,
     const ClangImporterOptions &clangImporterOpts, const CASOptions &casOpts,
-    bool suppressRemarks, RequireOSSAModules_t RequireOSSAModules) {
+    bool suppressRemarks) {
   GenericArgs.push_back("-frontend");
   // Start with a genericSubInvocation that copies various state from our
   // invoking ASTContext.
@@ -1791,12 +1770,6 @@ void InterfaceSubContextDelegateImpl::inheritOptionsForBuildingInterface(
   genericSubInvocation.getLangOptions().EnableObjCAttrRequiresFoundation = false;
   GenericArgs.push_back("-disable-objc-attr-requires-foundation-module");
 
-  // If we are supposed to use RequireOSSAModules, do so.
-  if (RequireOSSAModules) {
-    genericSubInvocation.getSILOptions().EnableOSSAModules = true;
-    GenericArgs.push_back("-enable-ossa-modules");
-  }
-
   if (LangOpts.DisableAvailabilityChecking) {
     genericSubInvocation.getLangOptions().DisableAvailabilityChecking = true;
     GenericArgs.push_back("-disable-availability-checking");
@@ -1885,14 +1858,12 @@ InterfaceSubContextDelegateImpl::InterfaceSubContextDelegateImpl(
     StringRef moduleCachePath, StringRef prebuiltCachePath,
     StringRef backupModuleInterfaceDir,
     ArrayRef<std::pair<std::string, std::string>> replayPrefixMap,
-    bool serializeDependencyHashes, bool trackSystemDependencies,
+    bool serializeDependencyHashes, bool trackSystemDependencies)
-    RequireOSSAModules_t requireOSSAModules)
     : SM(SM), Diags(Diags), ArgSaver(Allocator) {
   genericSubInvocation.setMainExecutablePath(LoaderOpts.mainExecutablePath);
   inheritOptionsForBuildingInterface(LoaderOpts.requestedAction, searchPathOpts,
                                      langOpts, clangImporterOpts, casOpts,
-                                     Diags->getSuppressRemarks(),
+                                     Diags->getSuppressRemarks());
-                                     requireOSSAModules);
   // Configure front-end input.
   auto &SubFEOpts = genericSubInvocation.getFrontendOptions();
   SubFEOpts.RequestedAction = LoaderOpts.requestedAction;
@@ -2447,7 +2418,6 @@ bool ExplicitSwiftModuleLoader::canImportModule(
 
   auto metaData = serialization::validateSerializedAST(
       (*moduleBuf)->getBuffer(),
-      Ctx.SILOpts.EnableOSSAModules,
       Ctx.LangOpts.SDKName);
   versionInfo->setVersion(metaData.userModuleVersion,
                           ModuleVersionSourceKind::SwiftBinaryModule);
@@ -2802,7 +2772,7 @@ bool ExplicitCASModuleLoader::canImportModule(
     return false;
   }
   auto metaData = serialization::validateSerializedAST(
-      moduleBuf->getBuffer(), Ctx.SILOpts.EnableOSSAModules,
+      moduleBuf->getBuffer(),
       Ctx.LangOpts.SDKName);
   versionInfo->setVersion(metaData.userModuleVersion,
                           ModuleVersionSourceKind::SwiftBinaryModule);
@@ -2915,12 +2885,6 @@ static std::string getContextHash(const CompilerInvocation &CI,
       // Application extension.
       unsigned(CI.getLangOptions().EnableAppExtensionRestrictions),
 
-      // Whether or not OSSA modules are enabled.
-      //
-      // If OSSA modules are enabled, we use a separate namespace of modules to
-      // ensure that we compile all swift interface files with the option set.
-      unsigned(CI.getSILOptions().EnableOSSAModules),
-
       // Is the C++ interop enabled?
       unsigned(CI.getLangOptions().EnableCXXInterop),
 

lib/FrontendTool/FrontendTool.cpp

@@ -391,7 +391,7 @@ static bool buildModuleFromInterface(CompilerInstance &Instance) {
       Invocation.getOutputFilename(), ABIPath, FEOpts.CacheReplayPrefixMap,
       FEOpts.SerializeModuleInterfaceDependencyHashes,
       FEOpts.shouldTrackSystemDependencies(), LoaderOpts,
-      RequireOSSAModules_t(Invocation.getSILOptions()), IgnoreAdjacentModules);
+      IgnoreAdjacentModules);
 }
 
 static bool compileLLVMIR(CompilerInstance &Instance) {
@@ -1754,7 +1754,7 @@ static bool serializeSIB(SILModule *SM, const PrimarySpecificPaths &PSPs,
   serializationOpts.OutputPath = moduleOutputPath;
   serializationOpts.SerializeAllSIL = true;
   serializationOpts.IsSIB = true;
-  serializationOpts.IsOSSA = Context.SILOpts.EnableOSSAModules;
+  serializationOpts.IsOSSA = true;
 
   symbolgraphgen::SymbolGraphOptions symbolGraphOptions;
 

lib/SILOptimizer/PassManager/PassPipeline.cpp

@@ -543,16 +543,6 @@ void addFunctionPasses(SILPassPipelinePlan &P,
   P.addSemanticARCOpts();
   P.addCopyToBorrowOptimization();
 
-  if (!P.getOptions().EnableOSSAModules) {
-    if (P.getOptions().StopOptimizationBeforeLoweringOwnership)
-      return;
-
-    if (SILPrintFinalOSSAModule) {
-      addModulePrinterPipeline(P, "SIL Print Final OSSA Module");
-    }
-    P.addNonTransparentFunctionOwnershipModelEliminator();
-  }
-
   switch (OpLevel) {
   case OptimizationLevelKind::HighLevel:
     // Does not inline functions with defined semantics or effects.
@@ -566,13 +556,11 @@ void addFunctionPasses(SILPassPipelinePlan &P,
   }
 
   // Clean up Semantic ARC before we perform additional post-inliner opts.
-  if (P.getOptions().EnableOSSAModules) {
+  if (P.getOptions().CopyPropagation != CopyPropagationOption::Off) {
-    if (P.getOptions().CopyPropagation != CopyPropagationOption::Off) {
+    P.addCopyPropagation();
-      P.addCopyPropagation();
-    }
-    P.addSemanticARCOpts();
-    P.addCopyToBorrowOptimization();
   }
+  P.addSemanticARCOpts();
+  P.addCopyToBorrowOptimization();
 
   // Promote stack allocations to values and eliminate redundant
   // loads.
@@ -633,14 +621,12 @@ void addFunctionPasses(SILPassPipelinePlan &P,
   P.addARCSequenceOpts();
 
   // Run a final round of ARC opts when ownership is enabled.
-  if (P.getOptions().EnableOSSAModules) {
+  P.addDestroyHoisting();
-    P.addDestroyHoisting();
+  if (P.getOptions().CopyPropagation != CopyPropagationOption::Off) {
-    if (P.getOptions().CopyPropagation != CopyPropagationOption::Off) {
+    P.addCopyPropagation();
-      P.addCopyPropagation();
-    }
-    P.addSemanticARCOpts();
-    P.addCopyToBorrowOptimization();
   }
+  P.addSemanticARCOpts();
+  P.addCopyToBorrowOptimization();
 }
 
 static void addPerfDebugSerializationPipeline(SILPassPipelinePlan &P) {
@@ -1022,13 +1008,11 @@ SILPassPipelinePlan::getPerformancePassPipeline(const SILOptions &Options) {
 
   // Run one last copy propagation/semantic arc opts run before serialization/us
   // lowering ownership.
-  if (P.getOptions().EnableOSSAModules) {
+  if (P.getOptions().CopyPropagation != CopyPropagationOption::Off) {
-    if (P.getOptions().CopyPropagation != CopyPropagationOption::Off) {
+    P.addCopyPropagation();
-      P.addCopyPropagation();
-    }
-    P.addSemanticARCOpts();
-    P.addCopyToBorrowOptimization();
   }
+  P.addSemanticARCOpts();
+  P.addCopyToBorrowOptimization();
 
   P.addCrossModuleOptimization();
 
@@ -1042,10 +1026,9 @@ SILPassPipelinePlan::getPerformancePassPipeline(const SILOptions &Options) {
   if (Options.StopOptimizationAfterSerialization)
     return P;
 
-  if (P.getOptions().EnableOSSAModules && SILPrintFinalOSSAModule) {
+  if (SILPrintFinalOSSAModule) {
     addModulePrinterPipeline(P, "SIL Print Final OSSA Module");
   }
-  // Strip any transparent functions that still have ownership.
   P.addOwnershipModelEliminator();
 
   P.addAutodiffClosureSpecialization();
@@ -1126,7 +1109,6 @@ SILPassPipelinePlan::getOnonePassPipeline(const SILOptions &Options) {
   if (P.Options.StopOptimizationBeforeLoweringOwnership)
     return P;
 
-  // Now strip any transparent functions that still have ownership.
   P.addOwnershipModelEliminator();
 
   // Finally perform some small transforms.

lib/SILOptimizer/SILCombiner/SILCombine.cpp

@@ -669,10 +669,8 @@ class SILCombine : public SILFunctionTransform {
   void run() override {
     bool enableCopyPropagation =
         getOptions().CopyPropagation >= CopyPropagationOption::Optimizing;
-    if (getOptions().EnableOSSAModules) {
+    enableCopyPropagation =
-      enableCopyPropagation =
+        getOptions().CopyPropagation != CopyPropagationOption::Off;
-          getOptions().CopyPropagation != CopyPropagationOption::Off;
-    }
 
     SILCombiner Combiner(this, getOptions().RemoveRuntimeAsserts,
                          enableCopyPropagation);

lib/Serialization/ModuleFile.cpp

@@ -426,7 +426,7 @@ ModuleFile::getModuleName(ASTContext &Ctx, StringRef modulePath,
   bool isFramework = false;
   serialization::ValidationInfo loadInfo = ModuleFileSharedCore::load(
       "", "", std::move(newBuf), nullptr, nullptr,
-      /*isFramework=*/isFramework, Ctx.SILOpts.EnableOSSAModules,
+      /*isFramework=*/isFramework,
       Ctx.LangOpts.SDKName, Ctx.LangOpts.Target,
       Ctx.SearchPathOpts.DeserializedPathRecoverer, loadedModuleFile);
   Name = loadedModuleFile->Name.str();

lib/Serialization/ModuleFileSharedCore.cpp

@@ -242,7 +242,6 @@ static bool readOptionsBlock(llvm::BitstreamCursor &cursor,
 static ValidationInfo validateControlBlock(
     llvm::BitstreamCursor &cursor, SmallVectorImpl<uint64_t> &scratch,
     std::pair<uint16_t, uint16_t> expectedVersion,
-    bool requiresOSSAModules,
     bool requiresRevisionMatch,
     StringRef requiredSDK,
     std::optional<llvm::Triple> target,
@@ -486,7 +485,7 @@ static ValidationInfo validateControlBlock(
     }
     case control_block::IS_OSSA: {
       auto isModuleInOSSA = scratch[0];
-      if (requiresOSSAModules && !isModuleInOSSA)
+      if (!isModuleInOSSA)
         result.status = Status::NotInOSSA;
       break;
     }
@@ -615,7 +614,7 @@ bool serialization::isSerializedAST(StringRef data) {
 }
 
 ValidationInfo serialization::validateSerializedAST(
-    StringRef data, bool requiresOSSAModules,
+    StringRef data,
     StringRef requiredSDK,
     ExtendedValidationInfo *extendedInfo,
     SmallVectorImpl<SerializationOptions::FileDependency> *dependencies,
@@ -661,7 +660,6 @@ ValidationInfo serialization::validateSerializedAST(
       result = validateControlBlock(
           cursor, scratch,
           {SWIFTMODULE_VERSION_MAJOR, SWIFTMODULE_VERSION_MINOR},
-          requiresOSSAModules,
           /*requiresRevisionMatch=*/true,
           requiredSDK, target,
           extendedInfo, localObfuscator);
@@ -1213,7 +1211,6 @@ bool ModuleFileSharedCore::readModuleDocIfPresent(PathObfuscator &pathRecoverer)
 
       info = validateControlBlock(
           docCursor, scratch, {SWIFTDOC_VERSION_MAJOR, SWIFTDOC_VERSION_MINOR},
-          RequiresOSSAModules,
           /*requiresRevisionMatch*/false,
           /*requiredSDK*/StringRef(), /*target*/std::nullopt,
           /*extendedInfo*/nullptr, pathRecoverer);
@@ -1359,7 +1356,6 @@ bool ModuleFileSharedCore::readModuleSourceInfoIfPresent(PathObfuscator &pathRec
       info = validateControlBlock(
           infoCursor, scratch,
           {SWIFTSOURCEINFO_VERSION_MAJOR, SWIFTSOURCEINFO_VERSION_MINOR},
-          RequiresOSSAModules,
           /*requiresRevisionMatch*/false,
           /*requiredSDK*/StringRef(), /*target*/std::nullopt,
           /*extendedInfo*/nullptr, pathRecoverer);
@@ -1439,14 +1435,12 @@ ModuleFileSharedCore::ModuleFileSharedCore(
     std::unique_ptr<llvm::MemoryBuffer> moduleDocInputBuffer,
     std::unique_ptr<llvm::MemoryBuffer> moduleSourceInfoInputBuffer,
     bool isFramework,
-    bool requiresOSSAModules,
     StringRef requiredSDK,
     std::optional<llvm::Triple> target,
     serialization::ValidationInfo &info, PathObfuscator &pathRecoverer)
     : ModuleInputBuffer(std::move(moduleInputBuffer)),
       ModuleDocInputBuffer(std::move(moduleDocInputBuffer)),
-      ModuleSourceInfoInputBuffer(std::move(moduleSourceInfoInputBuffer)),
+      ModuleSourceInfoInputBuffer(std::move(moduleSourceInfoInputBuffer)) {
-      RequiresOSSAModules(requiresOSSAModules) {
   assert(!hasError());
   Bits.IsFramework = isFramework;
 
@@ -1493,7 +1487,6 @@ ModuleFileSharedCore::ModuleFileSharedCore(
       info = validateControlBlock(
           cursor, scratch,
           {SWIFTMODULE_VERSION_MAJOR, SWIFTMODULE_VERSION_MINOR},
-          RequiresOSSAModules,
           /*requiresRevisionMatch=*/true, requiredSDK, target,
           &extInfo, pathRecoverer);
       if (info.status != Status::Valid) {

lib/Serialization/ModuleFileSharedCore.h

@@ -114,9 +114,6 @@ class ModuleFileSharedCore {
   /// \c true if this module has incremental dependency information.
   bool HasIncrementalInfo = false;
 
-  /// \c true if this module was compiled with -enable-ossa-modules.
-  bool RequiresOSSAModules;
-
   /// An array of module names that are allowed to import this one.
   ArrayRef<StringRef> AllowableClientNames;
 
@@ -445,7 +442,6 @@ private:
       std::unique_ptr<llvm::MemoryBuffer> moduleDocInputBuffer,
       std::unique_ptr<llvm::MemoryBuffer> moduleSourceInfoInputBuffer,
       bool isFramework,
-      bool requiresOSSAModules,
       StringRef requiredSDK,
       std::optional<llvm::Triple> target,
       serialization::ValidationInfo &info, PathObfuscator &pathRecoverer);
@@ -573,8 +569,6 @@ public:
   /// of the buffer, even if there's an error in loading.
   /// \param isFramework If true, this is treated as a framework module for
   /// linking purposes.
-  /// \param requiresOSSAModules If true, this requires dependent modules to be
-  /// compiled with -enable-ossa-modules.
   /// \param requiredSDK A string denoting the name of the currently-used SDK,
   /// to ensure that the loaded module was built with a compatible SDK.
   /// \param target The target triple of the current compilation for
@@ -587,7 +581,7 @@ public:
        std::unique_ptr<llvm::MemoryBuffer> moduleInputBuffer,
        std::unique_ptr<llvm::MemoryBuffer> moduleDocInputBuffer,
        std::unique_ptr<llvm::MemoryBuffer> moduleSourceInfoInputBuffer,
-       bool isFramework, bool requiresOSSAModules,
+       bool isFramework,
        StringRef requiredSDK, std::optional<llvm::Triple> target,
        PathObfuscator &pathRecoverer,
        std::shared_ptr<const ModuleFileSharedCore> &theModule) {
@@ -595,7 +589,7 @@ public:
     auto *core = new ModuleFileSharedCore(
         std::move(moduleInputBuffer), std::move(moduleDocInputBuffer),
         std::move(moduleSourceInfoInputBuffer), isFramework,
-        requiresOSSAModules, requiredSDK, target, info,
+        requiredSDK, target, info,
         pathRecoverer);
     if (!moduleInterfacePath.empty()) {
       ArrayRef<char> path;

lib/Serialization/ScanningLoaders.cpp

@@ -252,7 +252,7 @@ SwiftModuleScanner::scanInterfaceFile(Identifier moduleID,
           if (adjacentBinaryModule != compiledCandidates.end()) {
             auto adjacentBinaryModulePackageOnlyImports =
                 getMatchingPackageOnlyImportsOfModule(
-                    *adjacentBinaryModule, isFramework, isRequiredOSSAModules(),
+                    *adjacentBinaryModule, isFramework,
                     Ctx.LangOpts.SDKName, Ctx.LangOpts.Target,
                     ScannerPackageName, Ctx.SourceMgr.getFileSystem().get(),
                     Ctx.SearchPathOpts.DeserializedPathRecoverer);
@@ -294,7 +294,7 @@ llvm::ErrorOr<ModuleDependencyInfo> SwiftModuleScanner::scanBinaryModuleFile(
   std::shared_ptr<const ModuleFileSharedCore> loadedModuleFile;
   serialization::ValidationInfo loadInfo = ModuleFileSharedCore::load(
       "", "", std::move(moduleBuf.get()), nullptr, nullptr, isFramework,
-      isRequiredOSSAModules(), Ctx.LangOpts.SDKName, Ctx.LangOpts.Target,
+      Ctx.LangOpts.SDKName, Ctx.LangOpts.Target,
       Ctx.SearchPathOpts.DeserializedPathRecoverer, loadedModuleFile);
 
   if (Ctx.SearchPathOpts.ScannerModuleValidation) {

lib/Serialization/SerializedModuleLoader.cpp

@@ -343,7 +343,7 @@ std::optional<std::string> SerializedModuleLoaderBase::invalidModuleReason(seria
 
 llvm::ErrorOr<std::vector<ScannerImportStatementInfo>>
 SerializedModuleLoaderBase::getMatchingPackageOnlyImportsOfModule(
-    Twine modulePath, bool isFramework, bool isRequiredOSSAModules,
+    Twine modulePath, bool isFramework,
     StringRef SDKName, const llvm::Triple &target, StringRef packageName,
     llvm::vfs::FileSystem *fileSystem, PathObfuscator &recoverer) {
   auto moduleBuf = fileSystem->getBufferForFile(modulePath);
@@ -355,7 +355,7 @@ SerializedModuleLoaderBase::getMatchingPackageOnlyImportsOfModule(
   std::shared_ptr<const ModuleFileSharedCore> loadedModuleFile;
   serialization::ValidationInfo loadInfo = ModuleFileSharedCore::load(
       "", "", std::move(moduleBuf.get()), nullptr, nullptr, isFramework,
-      isRequiredOSSAModules, SDKName, target, recoverer, loadedModuleFile);
+      SDKName, target, recoverer, loadedModuleFile);
 
   if (loadedModuleFile->getModulePackageName() != packageName)
     return importedModuleNames;
@@ -953,7 +953,6 @@ LoadedFile *SerializedModuleLoaderBase::loadAST(
       moduleInterfacePath, moduleInterfaceSourcePath,
       std::move(moduleInputBuffer), std::move(moduleDocInputBuffer),
       std::move(moduleSourceInfoInputBuffer), isFramework,
-      isRequiredOSSAModules(),
       Ctx.LangOpts.SDKName, Ctx.LangOpts.Target,
       Ctx.SearchPathOpts.DeserializedPathRecoverer, loadedModuleFileCore);
   SerializedASTFile *fileUnit = nullptr;
@@ -1113,10 +1112,6 @@ LoadedFile *SerializedModuleLoaderBase::loadAST(
   return fileUnit;
 }
 
-bool SerializedModuleLoaderBase::isRequiredOSSAModules() const {
-  return Ctx.SILOpts.EnableOSSAModules;
-}
-
 void swift::serialization::diagnoseSerializedASTLoadFailure(
     ASTContext &Ctx, SourceLoc diagLoc,
     const serialization::ValidationInfo &loadInfo,
@@ -1155,12 +1150,9 @@ void swift::serialization::diagnoseSerializedASTLoadFailure(
                        moduleBufferID);
     break;
   case serialization::Status::NotInOSSA:
-    if (Ctx.SerializationOpts.ExplicitModuleBuild ||
+    Ctx.Diags.diagnose(diagLoc,
-        Ctx.SILOpts.EnableOSSAModules) {
+                       diag::serialization_non_ossa_module_incompatible,
-      Ctx.Diags.diagnose(diagLoc,
+                       ModuleName);
-                         diag::serialization_non_ossa_module_incompatible,
-                         ModuleName);
-    }
     break;
   case serialization::Status::RevisionIncompatible:
     Ctx.Diags.diagnose(diagLoc, diag::serialization_module_incompatible_revision,
@@ -1498,7 +1490,7 @@ std::unique_ptr<llvm::MemoryBuffer> swift::extractEmbeddedBridgingHeaderContent(
   std::shared_ptr<const ModuleFileSharedCore> loadedModuleFile;
   serialization::ValidationInfo loadInfo = ModuleFileSharedCore::load(
       "", "", std::move(file), nullptr, nullptr, false,
-      Context.SILOpts.EnableOSSAModules, Context.LangOpts.SDKName,
+      Context.LangOpts.SDKName,
       Context.LangOpts.Target,
       Context.SearchPathOpts.DeserializedPathRecoverer,
       loadedModuleFile);
@@ -1553,7 +1545,7 @@ bool SerializedModuleLoaderBase::canImportModule(
 
   if (moduleInputBuffer) {
     auto metaData = serialization::validateSerializedAST(
-        moduleInputBuffer->getBuffer(), Ctx.SILOpts.EnableOSSAModules,
+        moduleInputBuffer->getBuffer(),
         Ctx.LangOpts.SDKName);
 
     // If we only found binary module, make sure that is valid.

stdlib/cmake/modules/AddSwiftStdlib.cmake

@@ -1920,9 +1920,6 @@ endfunction()
 # INSTALL_WITH_SHARED
 #   Install a static library target alongside shared libraries
 #
-# IMPORTS_NON_OSSA
-#   Imports a non-ossa module
-#
 # MACCATALYST_BUILD_FLAVOR
 #   Possible values are 'ios-like', 'macos-like', 'zippered', 'unzippered-twin'
 #   Presence of a build flavor requires SWIFT_MODULE_DEPENDS_MACCATALYST to be
@@ -1984,8 +1981,7 @@ function(add_swift_target_library name)
         SHARED
         STATIC
         NO_LINK_NAME
-        INSTALL_WITH_SHARED
+        INSTALL_WITH_SHARED)
-        IMPORTS_NON_OSSA)
   set(SWIFTLIB_single_parameter_options
         DEPLOYMENT_VERSION_IOS
         DEPLOYMENT_VERSION_OSX
@@ -2150,10 +2146,6 @@ function(add_swift_target_library name)
     list(APPEND SWIFTLIB_SWIFT_COMPILE_FLAGS "-Xfrontend;-enable-lexical-lifetimes=false")
   endif()
 
-  if (NOT SWIFTLIB_IMPORTS_NON_OSSA)
-    list(APPEND SWIFTLIB_SWIFT_COMPILE_FLAGS "-Xfrontend;-enable-ossa-modules")
-  endif()
-
   if(NOT DEFINED SWIFTLIB_INSTALL_BINARY_SWIFTMODULE)
     set(SWIFTLIB_INSTALL_BINARY_SWIFTMODULE TRUE)
   endif()

stdlib/public/Distributed/CMakeLists.txt

@@ -25,7 +25,7 @@ set(swift_distributed_link_libraries
   swiftCore)
 
 
-add_swift_target_library(swiftDistributed ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB IMPORTS_NON_OSSA 
+add_swift_target_library(swiftDistributed ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
   DistributedActor.cpp
   DistributedActor.swift
   DistributedActorSystem.swift

stdlib/public/Synchronization/CMakeLists.txt

@@ -96,7 +96,7 @@ set(SWIFT_SYNCHRNOIZATION_SWIFT_FLAGS
   "-strict-memory-safety"
 )
 
-add_swift_target_library(swiftSynchronization ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB IMPORTS_NON_OSSA 
+add_swift_target_library(swiftSynchronization ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
   ${SWIFT_SYNCHRONIZATION_SOURCES}
 
   GYB_SOURCES

stdlib/public/core/CMakeLists.txt

@@ -536,7 +536,6 @@ if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB)
       GYB_SOURCES ${SWIFTLIB_EMBEDDED_GYB_SOURCES}
       SWIFT_COMPILE_FLAGS
         ${swift_stdlib_compile_flags} -Xcc -ffreestanding -enable-experimental-feature Embedded
-        -Xfrontend -enable-ossa-modules
       MODULE_DIR "${CMAKE_BINARY_DIR}/lib/swift/embedded"
       SDK "embedded"
       ARCHITECTURE "${arch}"

test/DebugInfo/optimizer_pipeline.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend %s -emit-sil -g -Osize -parse-stdlib -parse-as-library -enable-ossa-modules -o - | %FileCheck %s
+// RUN: %target-swift-frontend %s -emit-sil -g -Osize -parse-stdlib -parse-as-library -o - | %FileCheck %s
 
 // REQUIRES: asserts
 

test/Interpreter/moveonly_linkedlist.swift

@@ -1,6 +1,5 @@
 // RUN: %target-run-simple-swift(-Xfrontend -sil-verify-all)
 // RUN: %target-run-simple-swift(-O -Xfrontend -sil-verify-all)
-// RUN: %target-run-simple-swift(-O -Xfrontend -sil-verify-all -Xfrontend -enable-ossa-modules)
 
 // REQUIRES: executable_test
 

test/Interpreter/moveonly_linkedlist_2_simple.swift

@@ -6,7 +6,6 @@
 // RUN: %FileCheck %s --check-prefix=CHECK-IR
 // RUN: %target-run-simple-swift(-parse-as-library -enable-builtin-module -Xfrontend -sil-verify-all) | %FileCheck %s
 // RUN: %target-run-simple-swift(-O -parse-as-library -enable-builtin-module -Xfrontend -sil-verify-all) | %FileCheck %s
-// RUN: %target-run-simple-swift(-O -parse-as-library -enable-builtin-module -Xfrontend -sil-verify-all -Xfrontend -enable-ossa-modules) | %FileCheck %s
 
 // REQUIRES: executable_test
 

test/ModuleInterface/ossa-modules/sdk-test-stdlib-ossa.swift

@@ -13,7 +13,7 @@
 // RUN: %empty-directory(%t/SDK/usr/lib/swift/%relative-platform-module-dir-prefix/Swift.swiftmodule)
 // RUN: %empty-directory(%t/PreBuiltSDKModules)
 
-// RUN: %target-swift-frontend -c -emit-module-interface-path %t/SDK/usr/lib/swift/%relative-platform-module-dir-prefix/Swift.swiftmodule/%target-swiftinterface-name -emit-module-path %t/SDK/usr/lib/swift/%relative-platform-module-dir-prefix/Swift.swiftmodule/%target-swiftmodule-name -o %t/Swift.o -parse-stdlib -module-name Swift -enable-library-evolution -module-cache-path %t/TempModuleCacheLibrary -swift-version 5 %s -disable-objc-interop -enable-ossa-modules
+// RUN: %target-swift-frontend -c -emit-module-interface-path %t/SDK/usr/lib/swift/%relative-platform-module-dir-prefix/Swift.swiftmodule/%target-swiftinterface-name -emit-module-path %t/SDK/usr/lib/swift/%relative-platform-module-dir-prefix/Swift.swiftmodule/%target-swiftmodule-name -o %t/Swift.o -parse-stdlib -module-name Swift -enable-library-evolution -module-cache-path %t/TempModuleCacheLibrary -swift-version 5 %s -disable-objc-interop
 
 // RUN: %swift_build_sdk_interfaces_base -o %t/PreBuiltSDKModules -j 1 -sdk %t/SDK -module-cache-path %t/TempModuleCacheBuilder %t/SDK -v
 
@@ -23,7 +23,7 @@
 
 // In this case also, we should not rebuild.
 
-// RUN: %target-swift-frontend -typecheck -sdk '%t/SDK' -prebuilt-module-cache-path '%t/PreBuiltSDKModules' -module-cache-path %t/TempModuleCacheOther -resource-dir '' -parse-stdlib -Rmodule-interface-rebuild %S/Inputs/sdk-test-stdlib-no-ossa-referent-no-rebuild-remark.swift -verify -enable-ossa-modules
+// RUN: %target-swift-frontend -typecheck -sdk '%t/SDK' -prebuilt-module-cache-path '%t/PreBuiltSDKModules' -module-cache-path %t/TempModuleCacheOther -resource-dir '' -parse-stdlib -Rmodule-interface-rebuild %S/Inputs/sdk-test-stdlib-no-ossa-referent-no-rebuild-remark.swift -verify
 
 // Flaky hangs: rdar://77288690
 // UNSUPPORTED: CPU=arm64, CPU=arm64e

test/SIL/Serialization/shared_function_serialization.sil

@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend %S/Inputs/shared_function_serialization_input.swift -o %t/Swift.swiftmodule -emit-module -parse-as-library -parse-stdlib -module-link-name swiftCore -module-name Swift -O -enable-ossa-modules
+// RUN: %target-swift-frontend %S/Inputs/shared_function_serialization_input.swift -o %t/Swift.swiftmodule -emit-module -parse-as-library -parse-stdlib -module-link-name swiftCore -module-name Swift -O
-// RUN: %target-sil-opt -enable-sil-verify-all -I %t -performance-linker -enable-ossa-modules -inline %s -o - | %FileCheck %s
+// RUN: %target-sil-opt -enable-sil-verify-all -I %t -performance-linker -inline %s -o - | %FileCheck %s
 
 // CHECK: sil private @top_level_code
 // CHECK: sil public_external [serialized] [ossa] @$ss1XVABycfC{{.*}}

test/SILOptimizer/jumpthreadtest.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -O -parse-as-library -emit-sil -enable-ossa-modules %s | %FileCheck %s
+// RUN: %target-swift-frontend -O -parse-as-library -emit-sil %s | %FileCheck %s
 // REQUIRES: PTRSIZE=32,swift_stdlib_asserts
 
 import Swift

test/SILOptimizer/opaque_values_mandatory.sil

@@ -1,7 +1,7 @@
 // RUN: %target-sil-opt -diagnostics -enable-sil-opaque-values %s | \
 // RUN:     %target-sil-opt -Onone-performance -enable-sil-verify-all \
 // RUN:                     -enable-sil-opaque-values -emit-sorted-sil \
-// RUN:                     -enable-ossa-modules -enable-copy-propagation \
+// RUN:                     -enable-copy-propagation \
 // RUN:                     -enable-lexical-borrow-scopes | \
 // RUN:     %FileCheck %s
 //

test/SILOptimizer/optimize_keypath_bug.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -emit-sil -O  -enable-ossa-modules -sil-verify-all %s
+// RUN: %target-swift-frontend -emit-sil -O -sil-verify-all %s
 // REQUIRES: OS=macosx
 
 import Foundation

test/SILOptimizer/outliner.swift

@@ -1,8 +1,6 @@
 // RUN: %target-swift-frontend -Osize -import-objc-header %S/Inputs/Outliner.h %s -Xllvm -sil-print-types -emit-sil -enforce-exclusivity=unchecked -enable-copy-propagation | %FileCheck %s
 // RUN: %target-swift-frontend -Osize -g -import-objc-header %S/Inputs/Outliner.h %s -Xllvm -sil-print-types -emit-sil -enforce-exclusivity=unchecked -enable-copy-propagation | %FileCheck %s
 
-// RUN: %target-swift-frontend -Osize -import-objc-header %S/Inputs/Outliner.h %s -Xllvm -sil-print-types -emit-sil -enforce-exclusivity=unchecked -enable-copy-propagation -enable-ossa-modules | %FileCheck %s
-// RUN: %target-swift-frontend -Osize -g -import-objc-header %S/Inputs/Outliner.h %s -Xllvm -sil-print-types -emit-sil -enforce-exclusivity=unchecked -enable-copy-propagation -enable-ossa-modules | %FileCheck %s
 // REQUIRES: objc_interop
 // REQUIRES: optimized_stdlib
 // REQUIRES: swift_in_compiler

test/SILOptimizer/sil_combine1.swift

@@ -1,5 +1,4 @@
 // RUN: %target-swift-frontend %s -O -Xllvm -sil-print-types -emit-sil | %FileCheck %s
-// RUN: %target-swift-frontend %s -O -Xllvm -sil-print-types -enable-ossa-modules -emit-sil | %FileCheck %s
 
 func curry<T1, T2, T3, T4>(_ f: @escaping (T1, T2, T3) -> T4) -> (T1) -> (T2) -> (T3) -> T4 {
   return { x in { y in { z in f(x, y, z) } } }

test/SILOptimizer/sil_combine_apply_ossa.sil

@@ -1,4 +1,4 @@
-// RUN: %target-sil-opt -sil-print-types -enable-ossa-modules -enable-copy-propagation -enable-lexical-lifetimes=false -enable-sil-verify-all %s -sil-combine -sil-combine-disable-alloc-stack-opts | %FileCheck %s
+// RUN: %target-sil-opt -sil-print-types -enable-copy-propagation -enable-lexical-lifetimes=false -enable-sil-verify-all %s -sil-combine -sil-combine-disable-alloc-stack-opts | %FileCheck %s
 
 import Swift
 import Builtin

test/SILOptimizer/sil_combine_concrete_existential_ossa.swift

@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend -O -enable-ossa-modules -Xllvm -sil-print-types -emit-sil -sil-verify-all -Xllvm -sil-disable-pass=function-signature-opts %s | %FileCheck %s
+// RUN: %target-swift-frontend -O -Xllvm -sil-print-types -emit-sil -sil-verify-all -Xllvm -sil-disable-pass=function-signature-opts %s | %FileCheck %s
-// RUN: %target-swift-frontend -O -enable-ossa-modules -Xllvm -sil-print-types -emit-sil -Xllvm -sil-verify-force-analysis-around-pass=devirtualizer -Xllvm -sil-disable-pass=function-signature-opts %s | %FileCheck %s
+// RUN: %target-swift-frontend -O -Xllvm -sil-print-types -emit-sil -Xllvm -sil-verify-force-analysis-around-pass=devirtualizer -Xllvm -sil-disable-pass=function-signature-opts %s | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 

test/SILOptimizer/simplify_cfg_crash.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -O %s -enable-ossa-modules -emit-sil -o /dev/null
+// RUN: %target-swift-frontend -O %s -emit-sil -o /dev/null
 
 public class X {}
 

test/SILOptimizer/stdlib/Atomics.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -O -Xllvm -sil-print-types -emit-sil -disable-availability-checking -enable-ossa-modules %s | %IRGenFileCheck %s
+// RUN: %target-swift-frontend -O -Xllvm -sil-print-types -emit-sil -disable-availability-checking %s | %IRGenFileCheck %s
 
 // REQUIRES: synchronization
 

test/SILOptimizer/string_optimization.swift

@@ -1,5 +1,4 @@
 // RUN: %target-build-swift -O %s -module-name=test -Xfrontend -sil-verify-all -emit-sil | %FileCheck %s
-// RUN: %target-build-swift -O %s -module-name=test -Xfrontend -sil-verify-all -emit-sil -Xfrontend -enable-ossa-modules | %FileCheck %s
 
 // RUN: %empty-directory(%t) 
 // RUN: %target-build-swift -O -module-name=test %s -o %t/a.out

test/SILOptimizer/templvalueopt.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -module-name=test -O -enable-ossa-modules -Xllvm -sil-print-types -emit-sil  %s | %FileCheck %s
+// RUN: %target-swift-frontend -module-name=test -O -Xllvm -sil-print-types -emit-sil  %s | %FileCheck %s
 
 // RUN: %empty-directory(%t) 
 // RUN: %target-build-swift -O -module-name=test %s -o %t/a.out

test/ScanDependencies/enable-ossa-modules-pass-down.swift

@@ -1,21 +0,0 @@
-// REQUIRES: objc_interop
-// RUN: %empty-directory(%t)
-// RUN: mkdir -p %t/clang-module-cache
-// RUN: mkdir -p %t/Frameworks
-// RUN: mkdir -p %t/Frameworks/E.framework/
-// RUN: mkdir -p %t/Frameworks/E.framework/Modules
-// RUN: mkdir -p %t/Frameworks/E.framework/Modules/E.swiftmodule
-
-// Copy over the interface
-// RUN: cp %S/Inputs/Swift/E.swiftinterface %t/Frameworks/E.framework/Modules/E.swiftmodule/%module-target-triple.swiftinterface
-
-// Run the scan
-// RUN: %target-swift-frontend -scan-dependencies -enable-ossa-modules -disable-implicit-swift-modules -module-load-mode prefer-interface %s -o %t/deps.json -F %t/Frameworks/ -sdk %t
-// RUN: %validate-json %t/deps.json | %FileCheck %s
-
-import E
-
-// CHECK: E.swiftmodule/{{.*}}.swiftinterface
-// CHECK: "commandLine": [
-// CHECK: "-enable-ossa-modules"
-// CHECK: ]

test/Serialization/early-serialization.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-module -O -module-name Swift -module-link-name swiftCore -parse-as-library -parse-stdlib -emit-module %s -o %t/Swift.swiftmodule -enable-ossa-modules
+// RUN: %target-swift-frontend -emit-module -O -module-name Swift -module-link-name swiftCore -parse-as-library -parse-stdlib -emit-module %s -o %t/Swift.swiftmodule
 // RUN: %target-sil-opt -enable-sil-verify-all %t/Swift.swiftmodule -emit-sorted-sil -o - | %FileCheck %s
 
 // Test that early serialization works as expected:

test/embedded/basic-modules-validation-no-stdlib.swift

@@ -6,7 +6,7 @@
 // RUN: %target-swift-frontend -emit-ir -I %t %t/Main.swift -parse-stdlib -enable-experimental-feature Embedded -wmo
 
 // MyModule is not embedded - error
-// RUN: %target-swift-frontend -emit-module -enable-ossa-modules -o %t/MyModule.swiftmodule %t/MyModule.swift -parse-stdlib -wmo
+// RUN: %target-swift-frontend -emit-module -o %t/MyModule.swiftmodule %t/MyModule.swift -parse-stdlib -wmo
 // RUN: not %target-swift-frontend -emit-ir -I %t %t/Main.swift -parse-stdlib -enable-experimental-feature Embedded -wmo 2>&1 | %FileCheck %s --check-prefix CHECK-A
 
 // main module is not embedded - error

test/sil-func-extractor/load-serialized-sil.swift

@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend -primary-file %s -module-name Swift -g -module-link-name swiftCore -O -parse-as-library -parse-stdlib -emit-module -emit-module-path - -enable-ossa-modules -o /dev/null | %target-sil-func-extractor -module-name="Swift" -enable-ossa-modules -func='$ss1XV4testyyF' | %FileCheck %s
+// RUN: %target-swift-frontend -primary-file %s -module-name Swift -g -module-link-name swiftCore -O -parse-as-library -parse-stdlib -emit-module -emit-module-path - -o /dev/null | %target-sil-func-extractor -module-name="Swift" -func='$ss1XV4testyyF' | %FileCheck %s
-// RUN: %target-swift-frontend -primary-file %s -module-name Swift -g -O -parse-as-library -parse-stdlib -emit-sib -enable-ossa-modules -o - | %target-sil-func-extractor -module-name="Swift" -enable-ossa-modules -func='$ss1XV4testyyF' | %FileCheck %s -check-prefix=SIB-CHECK
+// RUN: %target-swift-frontend -primary-file %s -module-name Swift -g -O -parse-as-library -parse-stdlib -emit-sib -o - | %target-sil-func-extractor -module-name="Swift" -func='$ss1XV4testyyF' | %FileCheck %s -check-prefix=SIB-CHECK
 
 // CHECK: import Builtin
 // CHECK: import Swift

test/sil-opt/sil-opt.swift

@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend -primary-file %s -enable-ossa-modules -module-name Swift -g -module-link-name swiftCore -O -parse-as-library -parse-stdlib -emit-module -emit-module-path - -o /dev/null | %target-sil-opt -enable-sil-verify-all -module-name="Swift" -emit-sorted-sil | %FileCheck %s
+// RUN: %target-swift-frontend -primary-file %s -module-name Swift -g -module-link-name swiftCore -O -parse-as-library -parse-stdlib -emit-module -emit-module-path - -o /dev/null | %target-sil-opt -enable-sil-verify-all -module-name="Swift" -emit-sorted-sil | %FileCheck %s
-// RUN: %target-swift-frontend -primary-file %s -enable-ossa-modules -module-name Swift -g -O -parse-as-library -parse-stdlib -emit-sib -o - | %target-sil-opt -enable-sil-verify-all -module-name="Swift" -emit-sorted-sil | %FileCheck %s -check-prefix=SIB-CHECK
+// RUN: %target-swift-frontend -primary-file %s -module-name Swift -g -O -parse-as-library -parse-stdlib -emit-sib -o - | %target-sil-opt -enable-sil-verify-all -module-name="Swift" -emit-sorted-sil | %FileCheck %s -check-prefix=SIB-CHECK
 
 // CHECK: import Builtin
 // CHECK: import Swift

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

@@ -46,12 +46,12 @@ void anchorForGetMainExecutable() {}
 using namespace llvm::MachO;
 
 static bool validateModule(
-    llvm::StringRef data, bool Verbose, bool requiresOSSAModules,
+    llvm::StringRef data, bool Verbose,
     swift::serialization::ValidationInfo &info,
     swift::serialization::ExtendedValidationInfo &extendedInfo,
     llvm::SmallVectorImpl<swift::serialization::SearchPath> &searchPaths) {
   info = swift::serialization::validateSerializedAST(
-      data, requiresOSSAModules,
+      data,
       /*requiredSDK*/ StringRef(), &extendedInfo, /* dependencies*/ nullptr,
       &searchPaths);
   if (info.status != swift::serialization::Status::Valid) {
@@ -284,9 +284,6 @@ int main(int argc, char **argv) {
   opt<bool> QualifyTypes("qualify-types", desc("Qualify dumped types"),
                          cat(Visible));
 
-  opt<bool> EnableOSSAModules("enable-ossa-modules", init(false),
-                              desc("Serialize modules in OSSA"), cat(Visible));
-
   ParseCommandLineOptions(argc, argv);
 
   // Unregister our options so they don't interfere with the command line
@@ -331,7 +328,6 @@ int main(int argc, char **argv) {
     info = {};
     extendedInfo = {};
     if (!validateModule(StringRef(Module.first, Module.second), Verbose,
-                        EnableOSSAModules,
                         info, extendedInfo, searchPaths)) {
       llvm::errs() << "Malformed module!\n";
       return 1;
@@ -355,7 +351,6 @@ int main(int argc, char **argv) {
   Invocation.setModuleName("lldbtest");
   Invocation.getClangImporterOptions().ModuleCachePath = ModuleCachePath;
   Invocation.getLangOptions().EnableMemoryBufferImporter = true;
-  Invocation.getSILOptions().EnableOSSAModules = EnableOSSAModules;
 
   if (!ResourceDir.empty()) {
     Invocation.setRuntimeResourcePath(ResourceDir);

unittests/FrontendTool/ModuleLoadingTests.cpp

@@ -111,8 +111,7 @@ protected:
 
     ctx->addModuleInterfaceChecker(
       std::make_unique<ModuleInterfaceCheckerImpl>(*ctx, cacheDir,
-        prebuiltCacheDir, ModuleInterfaceLoaderOptions(),
+        prebuiltCacheDir, ModuleInterfaceLoaderOptions()));
-        swift::RequireOSSAModules_t(silOpts)));
 
     auto loader = ModuleInterfaceLoader::create(
         *ctx, *static_cast<ModuleInterfaceCheckerImpl*>(
@@ -152,7 +151,7 @@ protected:
 
     auto bufData = (*bufOrErr)->getBuffer();
     auto validationInfo = serialization::validateSerializedAST(
-        bufData, silOpts.EnableOSSAModules,
+        bufData,
         /*requiredSDK*/StringRef());
     ASSERT_EQ(serialization::Status::Valid, validationInfo.status);
     ASSERT_EQ(bufData, moduleBuffer->getBuffer());