diff --git a/docs/Branches.md b/docs/Branches.md
index edd871fe00b..e533c3af5e3 100644
--- a/docs/Branches.md
+++ b/docs/Branches.md
@@ -56,9 +56,17 @@ You can use any of the branch names as the argument to `--scheme`, such as `mast
 
 - Swift: new commits go to `master`
 
-- LLVM Project: new commits go to `swift/master-next`
+- LLVM Project: the destination branch depends on the kind of change that must be made:
 
-...then cherry-pick to the release branch (`swift/swift-x.y-branch`) if necessary, following the appropriate release process. (Usually this means filling out a standard template, finding someone to review your code if that hasn't already happened, and getting approval from that repo's *release manager.)*
+  1) LLVM Project changes that don't depend on Swift: New commits go to `master` in the upstream [llvm-project](https://github.com/llvm/llvm-project).
+
+  ... then these commits can be cherry-picked to an appropriate, `swift/master` aligned `apple/stable/*` branch in Apple's fork of [llvm-project](https://github.com/apple/llvm-project). Please see
+  [Apple's branching scheme](https://github.com/apple/llvm-project/blob/apple/master/apple-docs/AppleBranchingScheme.md)
+  document to determine which `apple/stable/*` branch you should cherry-pick to.
+
+  2) Changes that depend on Swift (this only applies to LLDB): new commits go to `swift/master-next`
+
+  ...then cherry-pick to the release branch (`swift/swift-x.y-branch`) if necessary, following the appropriate release   process. (Usually this means filling out a standard template, finding someone to review your code if that hasn't already happened, and getting approval from that repo's *release manager.)*
 
 ## Automerging
 
diff --git a/include/swift/AST/IRGenOptions.h b/include/swift/AST/IRGenOptions.h
index dc6cb89d402..699385ad271 100644
--- a/include/swift/AST/IRGenOptions.h
+++ b/include/swift/AST/IRGenOptions.h
@@ -272,7 +272,7 @@ public:
   /// Appends to \p os an arbitrary string representing all options which
   /// influence the llvm compilation but are not reflected in the llvm module
   /// itself.
-  void writeLLVMCodeGenOptionsTo(llvm::raw_ostream &os) {
+  void writeLLVMCodeGenOptionsTo(llvm::raw_ostream &os) const {
     // We put a letter between each value simply to keep them from running into
     // one another. There might be a vague correspondence between meaning and
     // letter, but don't sweat it.
@@ -303,6 +303,16 @@ public:
     return OptMode == OptimizationMode::ForSize;
   }
 
+  std::string getDebugFlags(StringRef PrivateDiscriminator) const {
+    std::string Flags = DebugFlags;
+    if (!PrivateDiscriminator.empty()) {
+      if (!Flags.empty())
+        Flags += " ";
+      Flags += ("-private-discriminator " + PrivateDiscriminator).str();
+    }
+    return Flags;
+  }
+
   /// Return a hash code of any components from these options that should
   /// contribute to a Swift Bridging PCH hash.
   llvm::hash_code getPCHHashComponents() const {
diff --git a/include/swift/AST/TypeMatcher.h b/include/swift/AST/TypeMatcher.h
index a81232d1d6b..05fdd68f26c 100644
--- a/include/swift/AST/TypeMatcher.h
+++ b/include/swift/AST/TypeMatcher.h
@@ -114,8 +114,7 @@ class TypeMatcher {
     bool visitUnresolvedType(CanUnresolvedType firstType, Type secondType,
                              Type sugaredFirstType) {
       // Unresolved types never match.
-      return mismatch(firstType.getPointer(), secondType,                \
-                      sugaredFirstType);                                 \
+      return mismatch(firstType.getPointer(), secondType, sugaredFirstType);
     }
 
     bool visitTupleType(CanTupleType firstTuple, Type secondType,
diff --git a/include/swift/AST/Types.h b/include/swift/AST/Types.h
index e27eab4896e..c0cee8dab04 100644
--- a/include/swift/AST/Types.h
+++ b/include/swift/AST/Types.h
@@ -3859,7 +3859,7 @@ namespace Lowering {
 /// function parameter and result types.
 class SILFunctionType final : public TypeBase, public llvm::FoldingSetNode,
     private llvm::TrailingObjects<SILFunctionType, SILParameterInfo,
-                                  SILResultInfo> {
+                                  SILResultInfo, SILYieldInfo, CanType> {
   friend TrailingObjects;
 
   size_t numTrailingObjects(OverloadToken<SILParameterInfo>) const {
@@ -3867,7 +3867,15 @@ class SILFunctionType final : public TypeBase, public llvm::FoldingSetNode,
   }
 
   size_t numTrailingObjects(OverloadToken<SILResultInfo>) const {
-    return hasErrorResult() ? 1 : 0;
+    return getNumResults() + (hasErrorResult() ? 1 : 0);
+  }
+
+  size_t numTrailingObjects(OverloadToken<SILYieldInfo>) const {
+    return getNumYields();
+  }
+
+  size_t numTrailingObjects(OverloadToken<CanType>) const {
+    return hasResultCache() ? 2 : 0;
   }
 
 public:
@@ -4040,12 +4048,13 @@ private:
   unsigned NumAnyResults : 16;         // Not including the ErrorResult.
   unsigned NumAnyIndirectFormalResults : 16; // Subset of NumAnyResults.
 
+  // [SILFunctionType-layout]
   // The layout of a SILFunctionType in memory is:
   //   SILFunctionType
   //   SILParameterInfo[NumParameters]
   //   SILResultInfo[isCoroutine() ? 0 : NumAnyResults]
-  //   SILYieldInfo[isCoroutine() ? NumAnyResults : 0]
   //   SILResultInfo?    // if hasErrorResult()
+  //   SILYieldInfo[isCoroutine() ? NumAnyResults : 0]
   //   CanType?          // if !isCoro && NumAnyResults > 1, formal result cache
   //   CanType?          // if !isCoro && NumAnyResults > 1, all result cache
 
@@ -4058,34 +4067,16 @@ private:
   }
 
   MutableArrayRef<SILResultInfo> getMutableResults() {
-    auto *ptr = reinterpret_cast<SILResultInfo *>(getMutableParameters().end());
-    return {ptr, getNumResults()};
+    return {getTrailingObjects<SILResultInfo>(), getNumResults()};
   }
 
   MutableArrayRef<SILYieldInfo> getMutableYields() {
-    auto *ptr = reinterpret_cast<SILYieldInfo *>(getMutableParameters().end());
-    return {ptr, getNumYields()};
-  }
-
-  /// Return a pointer past the end of the formal results, whether they
-  /// are yield-results or normal results.
-  void *getEndOfFormalResults() {
-    return isCoroutine() ? static_cast<void*>(getMutableYields().end())
-                         : static_cast<void*>(getMutableResults().end());
+    return {getTrailingObjects<SILYieldInfo>(), getNumYields()};
   }
 
   SILResultInfo &getMutableErrorResult() {
     assert(hasErrorResult());
-    return *reinterpret_cast<SILResultInfo*>(getEndOfFormalResults());
-  }
-
-  /// Return a pointer past the end of all of the results, including the
-  /// error result if one is present.
-  void *getEndOfAllResults() {
-    void *end = getEndOfFormalResults();
-    if (hasErrorResult())
-      end = reinterpret_cast<char*>(end) + sizeof(SILResultInfo);
-    return end;
+    return *(getTrailingObjects<SILResultInfo>() + getNumResults());
   }
 
   /// Do we have slots for caches of the normal-result tuple type?
@@ -4095,14 +4086,13 @@ private:
 
   CanType &getMutableFormalResultsCache() const {
     assert(hasResultCache());
-    auto *ptr = const_cast<SILFunctionType *>(this)->getEndOfAllResults();
-    return *reinterpret_cast<CanType*>(ptr);
+    return *const_cast<SILFunctionType *>(this)->getTrailingObjects<CanType>();
   }
 
   CanType &getMutableAllResultsCache() const {
     assert(hasResultCache());
-    auto *ptr = const_cast<SILFunctionType *>(this)->getEndOfAllResults();
-    return *(reinterpret_cast<CanType *>(ptr) + 1);
+    return *(const_cast<SILFunctionType *>(this)->getTrailingObjects<CanType>()
+             + 1);
   }
 
   SILFunctionType(GenericSignature genericSig, ExtInfo ext,
diff --git a/include/swift/Frontend/Frontend.h b/include/swift/Frontend/Frontend.h
index e58c2c61c98..183892bce3e 100644
--- a/include/swift/Frontend/Frontend.h
+++ b/include/swift/Frontend/Frontend.h
@@ -328,7 +328,7 @@ public:
   /// in generating a cached PCH file for the bridging header.
   std::string getPCHHash() const;
 
-  SourceFile::ImplicitModuleImportKind getImplicitModuleImportKind() {
+  SourceFile::ImplicitModuleImportKind getImplicitModuleImportKind() const {
     if (getInputKind() == InputFileKind::SIL) {
       return SourceFile::ImplicitModuleImportKind::None;
     }
@@ -380,7 +380,7 @@ public:
 
   SerializationOptions
   computeSerializationOptions(const SupplementaryOutputPaths &outs,
-                              bool moduleIsPublic);
+                              bool moduleIsPublic) const;
 };
 
 /// A class which manages the state and execution of the compiler.
@@ -404,7 +404,7 @@ class CompilerInstance {
   /// Null if no tracker.
   std::unique_ptr<DependencyTracker> DepTracker;
 
-  ModuleDecl *MainModule = nullptr;
+  mutable ModuleDecl *MainModule = nullptr;
   SerializedModuleLoader *SML = nullptr;
   MemoryBufferSerializedModuleLoader *MemoryBufferLoader = nullptr;
 
@@ -453,14 +453,16 @@ public:
   void operator=(CompilerInstance &&) = delete;
 
   SourceManager &getSourceMgr() { return SourceMgr; }
+  const SourceManager &getSourceMgr() const { return SourceMgr; }
 
   DiagnosticEngine &getDiags() { return Diagnostics; }
+  const DiagnosticEngine &getDiags() const { return Diagnostics; }
 
   llvm::vfs::FileSystem &getFileSystem() { return *SourceMgr.getFileSystem(); }
 
-  ASTContext &getASTContext() {
-    return *Context;
-  }
+  ASTContext &getASTContext() { return *Context; }
+  const ASTContext &getASTContext() const { return *Context; }
+
   bool hasASTContext() const { return Context != nullptr; }
 
   SILOptions &getSILOptions() { return Invocation.getSILOptions(); }
@@ -483,11 +485,7 @@ public:
     DepTracker = std::make_unique<DependencyTracker>(TrackSystemDeps);
   }
   DependencyTracker *getDependencyTracker() { return DepTracker.get(); }
-
-  /// Set the SIL module for this compilation instance.
-  ///
-  /// The CompilerInstance takes ownership of the given SILModule object.
-  void setSILModule(std::unique_ptr<SILModule> M);
+  const DependencyTracker *getDependencyTracker() const { return DepTracker.get(); }
 
   SILModule *getSILModule() {
     return TheSILModule.get();
@@ -499,7 +497,7 @@ public:
     return static_cast<bool>(TheSILModule);
   }
 
-  ModuleDecl *getMainModule();
+  ModuleDecl *getMainModule() const;
 
   MemoryBufferSerializedModuleLoader *
   getMemoryBufferSerializedModuleLoader() const {
@@ -520,7 +518,7 @@ public:
 
   /// Gets the set of SourceFiles which are the primary inputs for this
   /// CompilerInstance.
-  ArrayRef<SourceFile *> getPrimarySourceFiles() {
+  ArrayRef<SourceFile *> getPrimarySourceFiles() const {
     return PrimarySourceFiles;
   }
 
@@ -530,7 +528,7 @@ public:
   ///
   /// FIXME: This should be removed eventually, once there are no longer any
   /// codepaths that rely on a single primary file.
-  SourceFile *getPrimarySourceFile() {
+  SourceFile *getPrimarySourceFile() const {
     if (PrimarySourceFiles.empty()) {
       return nullptr;
     } else {
diff --git a/include/swift/IRGen/IRGenPublic.h b/include/swift/IRGen/IRGenPublic.h
index 3d1c11c4877..e92e85d18e1 100644
--- a/include/swift/IRGen/IRGenPublic.h
+++ b/include/swift/IRGen/IRGenPublic.h
@@ -31,6 +31,7 @@ class IRGenModule;
 std::pair<IRGenerator *, IRGenModule *>
 createIRGenModule(SILModule *SILMod, StringRef OutputFilename,
                   StringRef MainInputFilenameForDebugInfo,
+                  StringRef PrivateDiscriminator,
                   llvm::LLVMContext &LLVMContext);
 
 /// Delete the IRGenModule and IRGenerator obtained by the above call.
diff --git a/include/swift/Immediate/Immediate.h b/include/swift/Immediate/Immediate.h
index 3a54005aeed..e4f78f50ba5 100644
--- a/include/swift/Immediate/Immediate.h
+++ b/include/swift/Immediate/Immediate.h
@@ -18,6 +18,7 @@
 #ifndef SWIFT_IMMEDIATE_IMMEDIATE_H
 #define SWIFT_IMMEDIATE_IMMEDIATE_H
 
+#include <memory>
 #include <string>
 #include <vector>
 
@@ -25,6 +26,7 @@ namespace swift {
   class CompilerInstance;
   class IRGenOptions;
   class SILOptions;
+  class SILModule;
 
   // Using LLVM containers to store command-line arguments turns out
   // to be a lose, because LLVM's execution engine demands this vector
@@ -37,7 +39,8 @@ namespace swift {
   ///
   /// \return the result returned from main(), if execution succeeded
   int RunImmediately(CompilerInstance &CI, const ProcessCmdLine &CmdLine,
-                     IRGenOptions &IRGenOpts, const SILOptions &SILOpts);
+                     const IRGenOptions &IRGenOpts, const SILOptions &SILOpts,
+                     std::unique_ptr<SILModule> &&SM);
 
   void runREPL(CompilerInstance &CI, const ProcessCmdLine &CmdLine,
                bool ParseStdlib);
diff --git a/include/swift/SIL/SILModule.h b/include/swift/SIL/SILModule.h
index 1e81ecb91d2..d72b69a29e2 100644
--- a/include/swift/SIL/SILModule.h
+++ b/include/swift/SIL/SILModule.h
@@ -254,7 +254,7 @@ private:
   bool wholeModule;
 
   /// The options passed into this SILModule.
-  SILOptions &Options;
+  const SILOptions &Options;
 
   /// Set if the SILModule was serialized already. It is used
   /// to ensure that the module is serialized only once.
@@ -270,7 +270,7 @@ private:
   // Intentionally marked private so that we need to use 'constructSIL()'
   // to construct a SILModule.
   SILModule(ModuleDecl *M, Lowering::TypeConverter &TC,
-            SILOptions &Options, const DeclContext *associatedDC,
+            const SILOptions &Options, const DeclContext *associatedDC,
             bool wholeModule);
 
   SILModule(const SILModule&) = delete;
@@ -351,13 +351,13 @@ public:
   /// source file.
   static std::unique_ptr<SILModule>
   constructSIL(ModuleDecl *M, Lowering::TypeConverter &TC,
-               SILOptions &Options, FileUnit *sf = nullptr);
+               const SILOptions &Options, FileUnit *sf = nullptr);
 
   /// Create and return an empty SIL module that we can
   /// later parse SIL bodies directly into, without converting from an AST.
   static std::unique_ptr<SILModule>
   createEmptyModule(ModuleDecl *M, Lowering::TypeConverter &TC,
-                    SILOptions &Options,
+                    const SILOptions &Options,
                     bool WholeModule = false);
 
   /// Get the Swift module associated with this SIL module.
@@ -390,7 +390,7 @@ public:
   /// Returns true if it is the optimized OnoneSupport module.
   bool isOptimizedOnoneSupportModule() const;
 
-  SILOptions &getOptions() const { return Options; }
+  const SILOptions &getOptions() const { return Options; }
 
   using iterator = FunctionListType::iterator;
   using const_iterator = FunctionListType::const_iterator;
diff --git a/include/swift/Subsystems.h b/include/swift/Subsystems.h
index 57b4fd6e318..2d577e7c7f3 100644
--- a/include/swift/Subsystems.h
+++ b/include/swift/Subsystems.h
@@ -234,12 +234,12 @@ namespace swift {
   /// SIL of all files in the module is present in the SILModule.
   std::unique_ptr<SILModule>
   performSILGeneration(ModuleDecl *M, Lowering::TypeConverter &TC,
-                       SILOptions &options);
+                       const SILOptions &options);
 
   /// Turn a source file into SIL IR.
   std::unique_ptr<SILModule>
   performSILGeneration(FileUnit &SF, Lowering::TypeConverter &TC,
-                       SILOptions &options);
+                       const SILOptions &options);
 
   using ModuleOrSourceFile = PointerUnion<ModuleDecl *, SourceFile *>;
 
@@ -263,13 +263,13 @@ namespace swift {
   /// Get the CPU, subtarget feature options, and triple to use when emitting code.
   std::tuple<llvm::TargetOptions, std::string, std::vector<std::string>,
              std::string>
-  getIRTargetOptions(IRGenOptions &Opts, ASTContext &Ctx);
+  getIRTargetOptions(const IRGenOptions &Opts, ASTContext &Ctx);
 
   /// Turn the given Swift module into either LLVM IR or native code
   /// and return the generated LLVM IR module.
   /// If you set an outModuleHash, then you need to call performLLVM.
   std::unique_ptr<llvm::Module>
-  performIRGeneration(IRGenOptions &Opts, ModuleDecl *M,
+  performIRGeneration(const IRGenOptions &Opts, ModuleDecl *M,
                       std::unique_ptr<SILModule> SILMod,
                       StringRef ModuleName, const PrimarySpecificPaths &PSPs,
                       llvm::LLVMContext &LLVMContext,
@@ -281,9 +281,10 @@ namespace swift {
   /// and return the generated LLVM IR module.
   /// If you set an outModuleHash, then you need to call performLLVM.
   std::unique_ptr<llvm::Module>
-  performIRGeneration(IRGenOptions &Opts, SourceFile &SF,
+  performIRGeneration(const IRGenOptions &Opts, SourceFile &SF,
                       std::unique_ptr<SILModule> SILMod,
                       StringRef ModuleName, const PrimarySpecificPaths &PSPs,
+                      StringRef PrivateDiscriminator,
                       llvm::LLVMContext &LLVMContext,
                       llvm::GlobalVariable **outModuleHash = nullptr,
                       llvm::StringSet<> *LinkerDirectives = nullptr);
@@ -291,7 +292,7 @@ namespace swift {
   /// Given an already created LLVM module, construct a pass pipeline and run
   /// the Swift LLVM Pipeline upon it. This does not cause the module to be
   /// printed, only to be optimized.
-  void performLLVMOptimizations(IRGenOptions &Opts, llvm::Module *Module,
+  void performLLVMOptimizations(const IRGenOptions &Opts, llvm::Module *Module,
                                 llvm::TargetMachine *TargetMachine);
 
   /// Wrap a serialized module inside a swift AST section in an object file.
@@ -299,7 +300,7 @@ namespace swift {
                                    StringRef OutputPath);
 
   /// Turn the given LLVM module into native code and return true on error.
-  bool performLLVM(IRGenOptions &Opts, ASTContext &Ctx, llvm::Module *Module,
+  bool performLLVM(const IRGenOptions &Opts, ASTContext &Ctx, llvm::Module *Module,
                    StringRef OutputFilename,
                    UnifiedStatsReporter *Stats=nullptr);
 
@@ -314,7 +315,7 @@ namespace swift {
   /// \param TargetMachine target of code gen, required.
   /// \param effectiveLanguageVersion version of the language, effectively.
   /// \param OutputFilename Filename for output.
-  bool performLLVM(IRGenOptions &Opts, DiagnosticEngine *Diags,
+  bool performLLVM(const IRGenOptions &Opts, DiagnosticEngine *Diags,
                    llvm::sys::Mutex *DiagMutex,
                    llvm::GlobalVariable *HashGlobal,
                    llvm::Module *Module,
@@ -324,13 +325,13 @@ namespace swift {
                    UnifiedStatsReporter *Stats=nullptr);
 
   /// Dump YAML describing all fixed-size types imported from the given module.
-  bool performDumpTypeInfo(IRGenOptions &Opts,
+  bool performDumpTypeInfo(const IRGenOptions &Opts,
                            SILModule &SILMod,
                            llvm::LLVMContext &LLVMContext);
 
   /// Creates a TargetMachine from the IRGen opts and AST Context.
   std::unique_ptr<llvm::TargetMachine>
-  createTargetMachine(IRGenOptions &Opts, ASTContext &Ctx);
+  createTargetMachine(const IRGenOptions &Opts, ASTContext &Ctx);
 
   /// A convenience wrapper for Parser functionality.
   class ParserUnit {
diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index 4e42c94749f..e41d830becd 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -3376,13 +3376,13 @@ CanSILFunctionType SILFunctionType::get(
 
   // All SILFunctionTypes are canonical.
 
-  // Allocate storage for the object.
-  size_t bytes = sizeof(SILFunctionType)
-                 + sizeof(SILParameterInfo) * params.size()
-                 + sizeof(SILYieldInfo) * yields.size()
-                 + sizeof(SILResultInfo) * normalResults.size()
-                 + (errorResult ? sizeof(SILResultInfo) : 0)
-                 + (normalResults.size() > 1 ? sizeof(CanType) * 2 : 0);
+  // See [SILFunctionType-layout]
+  bool hasResultCache = normalResults.size() > 1;
+  size_t bytes =
+    totalSizeToAlloc<SILParameterInfo, SILResultInfo, SILYieldInfo, CanType>(
+      params.size(), normalResults.size() + (errorResult ? 1 : 0),
+      yields.size(), hasResultCache ? 2 : 0);
+
   void *mem = ctx.Allocate(bytes, alignof(SILFunctionType));
 
   RecursiveTypeProperties properties;
@@ -3413,6 +3413,8 @@ CanSILFunctionType SILFunctionType::get(
                                 params, yields, normalResults, errorResult,
                                 substitutions, genericSigIsImplied,
                                 ctx, properties, witnessMethodConformance);
+  assert(fnType->hasResultCache() == hasResultCache);
+
   ctx.getImpl().SILFunctionTypes.InsertNode(fnType, insertPos);
   return CanSILFunctionType(fnType);
 }
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 3d36dbe0a7f..9d861e5b126 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -111,6 +111,54 @@ static void updateRuntimeLibraryPaths(SearchPathOptions &SearchPathOpts,
   }
 }
 
+static void
+setIRGenOutputOptsFromFrontendOptions(IRGenOptions &IRGenOpts,
+                                      const FrontendOptions &FrontendOpts) {
+  // Set the OutputKind for the given Action.
+  IRGenOpts.OutputKind = [](FrontendOptions::ActionType Action) {
+    switch (Action) {
+    case FrontendOptions::ActionType::EmitIR:
+      return IRGenOutputKind::LLVMAssembly;
+    case FrontendOptions::ActionType::EmitBC:
+      return IRGenOutputKind::LLVMBitcode;
+    case FrontendOptions::ActionType::EmitAssembly:
+      return IRGenOutputKind::NativeAssembly;
+    case FrontendOptions::ActionType::Immediate:
+      return IRGenOutputKind::Module;
+    case FrontendOptions::ActionType::EmitObject:
+    default:
+      // Just fall back to emitting an object file. If we aren't going to run
+      // IRGen, it doesn't really matter what we put here anyways.
+      return IRGenOutputKind::ObjectFile;
+    }
+  }(FrontendOpts.RequestedAction);
+
+  // If we're in JIT mode, set the requisite flags.
+  if (FrontendOpts.RequestedAction == FrontendOptions::ActionType::Immediate) {
+    IRGenOpts.UseJIT = true;
+    IRGenOpts.DebugInfoLevel = IRGenDebugInfoLevel::Normal;
+    IRGenOpts.DebugInfoFormat = IRGenDebugInfoFormat::DWARF;
+  }
+}
+
+static void
+setBridgingHeaderFromFrontendOptions(ClangImporterOptions &ImporterOpts,
+                                     const FrontendOptions &FrontendOpts) {
+  if (FrontendOpts.RequestedAction != FrontendOptions::ActionType::EmitPCH)
+    return;
+
+  // If there aren't any inputs, there's nothing to do.
+  if (!FrontendOpts.InputsAndOutputs.hasInputs())
+    return;
+
+  // If we aren't asked to output a bridging header, we don't need to set this.
+  if (ImporterOpts.PrecompiledHeaderOutputDir.empty())
+    return;
+
+  ImporterOpts.BridgingHeader =
+      FrontendOpts.InputsAndOutputs.getFilenameOfFirstInput();
+}
+
 void CompilerInvocation::setRuntimeResourcePath(StringRef Path) {
   SearchPathOpts.RuntimeResourcePath = Path;
   updateRuntimeLibraryPaths(SearchPathOpts, LangOpts.Target);
@@ -1486,6 +1534,10 @@ bool CompilerInvocation::parseArgs(
   setDefaultPrebuiltCacheIfNecessary(FrontendOpts, SearchPathOpts,
                                      LangOpts.Target);
 
+  // Now that we've parsed everything, setup some inter-option-dependent state.
+  setIRGenOutputOptsFromFrontendOptions(IRGenOpts, FrontendOpts);
+  setBridgingHeaderFromFrontendOptions(ClangImporterOpts, FrontendOpts);
+
   return false;
 }
 
diff --git a/lib/Frontend/Frontend.cpp b/lib/Frontend/Frontend.cpp
index a043b7353e5..5c0daf0020d 100644
--- a/lib/Frontend/Frontend.cpp
+++ b/lib/Frontend/Frontend.cpp
@@ -142,7 +142,7 @@ CompilerInvocation::getModuleInterfaceOutputPathForWholeModule() const {
 }
 
 SerializationOptions CompilerInvocation::computeSerializationOptions(
-    const SupplementaryOutputPaths &outs, bool moduleIsPublic) {
+    const SupplementaryOutputPaths &outs, bool moduleIsPublic) const {
   const FrontendOptions &opts = getFrontendOptions();
 
   SerializationOptions serializationOpts;
@@ -185,10 +185,6 @@ void CompilerInstance::createSILModule() {
       Invocation.getFrontendOptions().InputsAndOutputs.isWholeModule());
 }
 
-void CompilerInstance::setSILModule(std::unique_ptr<SILModule> M) {
-  TheSILModule = std::move(M);
-}
-
 void CompilerInstance::recordPrimaryInputBuffer(unsigned BufID) {
   PrimaryBufferIDs.insert(BufID);
 }
@@ -618,7 +614,7 @@ std::unique_ptr<SILModule> CompilerInstance::takeSILModule() {
   return std::move(TheSILModule);
 }
 
-ModuleDecl *CompilerInstance::getMainModule() {
+ModuleDecl *CompilerInstance::getMainModule() const {
   if (!MainModule) {
     Identifier ID = Context->getIdentifier(Invocation.getModuleName());
     MainModule = ModuleDecl::create(ID, *Context);
diff --git a/lib/FrontendTool/FrontendTool.cpp b/lib/FrontendTool/FrontendTool.cpp
index 8ece4bb67cb..a1bef6a198a 100644
--- a/lib/FrontendTool/FrontendTool.cpp
+++ b/lib/FrontendTool/FrontendTool.cpp
@@ -482,8 +482,7 @@ getFileOutputStream(StringRef OutputFilename, ASTContext &Ctx) {
 }
 
 /// Writes the Syntax tree to the given file
-static bool emitSyntax(SourceFile *SF, LangOptions &LangOpts,
-                       SourceManager &SM, StringRef OutputFilename) {
+static bool emitSyntax(SourceFile *SF, StringRef OutputFilename) {
   auto bufferID = SF->getBufferID();
   assert(bufferID && "frontend should have a buffer ID "
          "for the main source file");
@@ -510,8 +509,8 @@ static bool writeSIL(SILModule &SM, ModuleDecl *M, bool EmitVerboseSIL,
 }
 
 static bool writeSIL(SILModule &SM, const PrimarySpecificPaths &PSPs,
-                     CompilerInstance &Instance,
-                     CompilerInvocation &Invocation) {
+                     const CompilerInstance &Instance,
+                     const CompilerInvocation &Invocation) {
   const FrontendOptions &opts = Invocation.getFrontendOptions();
   return writeSIL(SM, Instance.getMainModule(), opts.EmitVerboseSIL,
                   PSPs.OutputFilename, opts.EmitSortedSIL);
@@ -569,25 +568,6 @@ printModuleInterfaceIfNeeded(StringRef outputPath,
   });
 }
 
-/// Returns the OutputKind for the given Action.
-static IRGenOutputKind getOutputKind(FrontendOptions::ActionType Action) {
-  switch (Action) {
-  case FrontendOptions::ActionType::EmitIR:
-    return IRGenOutputKind::LLVMAssembly;
-  case FrontendOptions::ActionType::EmitBC:
-    return IRGenOutputKind::LLVMBitcode;
-  case FrontendOptions::ActionType::EmitAssembly:
-    return IRGenOutputKind::NativeAssembly;
-  case FrontendOptions::ActionType::EmitObject:
-    return IRGenOutputKind::ObjectFile;
-  case FrontendOptions::ActionType::Immediate:
-    return IRGenOutputKind::Module;
-  default:
-    llvm_unreachable("Unknown ActionType which requires IRGen");
-    return IRGenOutputKind::ObjectFile;
-  }
-}
-
 namespace {
 
 /// If there is an error with fixits it writes the fixits as edits in json
@@ -660,10 +640,10 @@ static void debugFailWithCrash() {
 /// \return true on error.
 static bool emitIndexDataIfNeeded(SourceFile *PrimarySourceFile,
                                   const CompilerInvocation &Invocation,
-                                  CompilerInstance &Instance);
+                                  const CompilerInstance &Instance);
 
 static void countStatsOfSourceFile(UnifiedStatsReporter &Stats,
-                                   CompilerInstance &Instance,
+                                   const CompilerInstance &Instance,
                                    SourceFile *SF) {
   auto &C = Stats.getFrontendCounters();
   auto &SM = Instance.getSourceMgr();
@@ -743,16 +723,13 @@ createOptRecordFile(StringRef Filename, DiagnosticEngine &DE) {
   return File;
 }
 
-static bool precompileBridgingHeader(CompilerInvocation &Invocation,
-                                     CompilerInstance &Instance) {
+static bool precompileBridgingHeader(const CompilerInvocation &Invocation,
+                                     const CompilerInstance &Instance) {
   auto clangImporter = static_cast<ClangImporter *>(
       Instance.getASTContext().getClangModuleLoader());
   auto &ImporterOpts = Invocation.getClangImporterOptions();
   auto &PCHOutDir = ImporterOpts.PrecompiledHeaderOutputDir;
   if (!PCHOutDir.empty()) {
-    ImporterOpts.BridgingHeader =
-        Invocation.getFrontendOptions()
-            .InputsAndOutputs.getFilenameOfFirstInput();
     // Create or validate a persistent PCH.
     auto SwiftPCHHash = Invocation.getPCHHash();
     auto PCH = clangImporter->getOrCreatePCH(ImporterOpts, SwiftPCHHash);
@@ -765,8 +742,8 @@ static bool precompileBridgingHeader(CompilerInvocation &Invocation,
           .InputsAndOutputs.getSingleOutputFilename());
 }
 
-static bool precompileClangModule(CompilerInvocation &Invocation,
-                                  CompilerInstance &Instance) {
+static bool precompileClangModule(const CompilerInvocation &Invocation,
+                                  const CompilerInstance &Instance) {
   auto clangImporter = static_cast<ClangImporter *>(
       Instance.getASTContext().getClangModuleLoader());
   return clangImporter->emitPrecompiledModule(
@@ -777,8 +754,8 @@ static bool precompileClangModule(CompilerInvocation &Invocation,
           .InputsAndOutputs.getSingleOutputFilename());
 }
 
-static bool dumpPrecompiledClangModule(CompilerInvocation &Invocation,
-                                       CompilerInstance &Instance) {
+static bool dumpPrecompiledClangModule(const CompilerInvocation &Invocation,
+                                       const CompilerInstance &Instance) {
   auto clangImporter = static_cast<ClangImporter *>(
       Instance.getASTContext().getClangModuleLoader());
   return clangImporter->dumpPrecompiledModule(
@@ -788,7 +765,7 @@ static bool dumpPrecompiledClangModule(CompilerInvocation &Invocation,
           .InputsAndOutputs.getSingleOutputFilename());
 }
 
-static bool buildModuleFromInterface(CompilerInvocation &Invocation,
+static bool buildModuleFromInterface(const CompilerInvocation &Invocation,
                                      CompilerInstance &Instance) {
   const FrontendOptions &FEOpts = Invocation.getFrontendOptions();
   assert(FEOpts.InputsAndOutputs.hasSingleInput());
@@ -804,7 +781,7 @@ static bool buildModuleFromInterface(CompilerInvocation &Invocation,
       FEOpts.TrackSystemDeps, FEOpts.RemarkOnRebuildFromModuleInterface);
 }
 
-static bool compileLLVMIR(CompilerInvocation &Invocation,
+static bool compileLLVMIR(const CompilerInvocation &Invocation,
                           CompilerInstance &Instance,
                           UnifiedStatsReporter *Stats) {
   auto &LLVMContext = getGlobalLLVMContext();
@@ -840,18 +817,14 @@ static bool compileLLVMIR(CompilerInvocation &Invocation,
         Err.getMessage());
     return true;
   }
-  IRGenOptions &IRGenOpts = Invocation.getIRGenOptions();
-  // TODO: remove once the frontend understands what action it should perform
-  IRGenOpts.OutputKind =
-      getOutputKind(Invocation.getFrontendOptions().RequestedAction);
-
-  return performLLVM(IRGenOpts, Instance.getASTContext(), Module.get(),
+  return performLLVM(Invocation.getIRGenOptions(),
+                     Instance.getASTContext(), Module.get(),
                      Invocation.getFrontendOptions()
                          .InputsAndOutputs.getSingleOutputFilename(),
                      Stats);
 }
 
-static void verifyGenericSignaturesIfNeeded(CompilerInvocation &Invocation,
+static void verifyGenericSignaturesIfNeeded(const CompilerInvocation &Invocation,
                                             ASTContext &Context) {
   auto verifyGenericSignaturesInModule =
       Invocation.getFrontendOptions().VerifyGenericSignaturesInModule;
@@ -861,8 +834,8 @@ static void verifyGenericSignaturesIfNeeded(CompilerInvocation &Invocation,
     GenericSignatureBuilder::verifyGenericSignaturesInModule(module);
 }
 
-static void dumpAndPrintScopeMap(CompilerInvocation &Invocation,
-                                 CompilerInstance &Instance, SourceFile *SF) {
+static void dumpAndPrintScopeMap(const CompilerInvocation &Invocation,
+                                 const CompilerInstance &Instance, SourceFile *SF) {
   // Not const because may require reexpansion
   ASTScope &scope = SF->getScope();
 
@@ -880,8 +853,8 @@ static void dumpAndPrintScopeMap(CompilerInvocation &Invocation,
   }
 }
 
-static SourceFile *getPrimaryOrMainSourceFile(CompilerInvocation &Invocation,
-                                              CompilerInstance &Instance) {
+static SourceFile *getPrimaryOrMainSourceFile(const CompilerInvocation &Invocation,
+                                              const CompilerInstance &Instance) {
   SourceFile *SF = Instance.getPrimarySourceFile();
   if (!SF) {
     SourceFileKind Kind = Invocation.getSourceFileKind();
@@ -892,7 +865,7 @@ static SourceFile *getPrimaryOrMainSourceFile(CompilerInvocation &Invocation,
 
 /// Dumps the AST of all available primary source files. If corresponding output
 /// files were specified, use them; otherwise, dump the AST to stdout.
-static void dumpAST(CompilerInvocation &Invocation,
+static void dumpAST(const CompilerInvocation &Invocation,
                     CompilerInstance &Instance) {
   auto primaryFiles = Instance.getPrimarySourceFiles();
   if (!primaryFiles.empty()) {
@@ -914,10 +887,10 @@ static void dumpAST(CompilerInvocation &Invocation,
 /// CompilerInstance::performSema()), so dump or print the main source file and
 /// return.
 
-static Optional<bool> dumpASTIfNeeded(CompilerInvocation &Invocation,
+static Optional<bool> dumpASTIfNeeded(const CompilerInvocation &Invocation,
                                       CompilerInstance &Instance) {
-  FrontendOptions &opts = Invocation.getFrontendOptions();
-  FrontendOptions::ActionType Action = opts.RequestedAction;
+  const FrontendOptions &opts = Invocation.getFrontendOptions();
+  const FrontendOptions::ActionType Action = opts.RequestedAction;
   ASTContext &Context = Instance.getASTContext();
   switch (Action) {
   default:
@@ -946,7 +919,6 @@ static Optional<bool> dumpASTIfNeeded(CompilerInvocation &Invocation,
 
   case FrontendOptions::ActionType::EmitSyntax:
     emitSyntax(getPrimaryOrMainSourceFile(Invocation, Instance),
-               Invocation.getLangOptions(), Instance.getSourceMgr(),
                opts.InputsAndOutputs.getSingleOutputFilename());
     break;
 
@@ -963,7 +935,7 @@ static Optional<bool> dumpASTIfNeeded(CompilerInvocation &Invocation,
 }
 
 static void emitReferenceDependenciesForAllPrimaryInputsIfNeeded(
-    CompilerInvocation &Invocation, CompilerInstance &Instance) {
+    const CompilerInvocation &Invocation, CompilerInstance &Instance) {
   if (Invocation.getFrontendOptions()
           .InputsAndOutputs.hasReferenceDependenciesPath() &&
       Instance.getPrimarySourceFiles().empty()) {
@@ -990,8 +962,8 @@ static void emitReferenceDependenciesForAllPrimaryInputsIfNeeded(
   }
 }
 static void
-emitSwiftRangesForAllPrimaryInputsIfNeeded(CompilerInvocation &Invocation,
-                                           CompilerInstance &Instance) {
+emitSwiftRangesForAllPrimaryInputsIfNeeded(const CompilerInvocation &Invocation,
+                                           const CompilerInstance &Instance) {
   if (Invocation.getFrontendOptions().InputsAndOutputs.hasSwiftRangesPath() &&
       Instance.getPrimarySourceFiles().empty()) {
     Instance.getASTContext().Diags.diagnose(
@@ -1008,8 +980,8 @@ emitSwiftRangesForAllPrimaryInputsIfNeeded(CompilerInvocation &Invocation,
   }
 }
 static void
-emitCompiledSourceForAllPrimaryInputsIfNeeded(CompilerInvocation &Invocation,
-                                              CompilerInstance &Instance) {
+emitCompiledSourceForAllPrimaryInputsIfNeeded(const CompilerInvocation &Invocation,
+                                              const CompilerInstance &Instance) {
   if (Invocation.getFrontendOptions()
           .InputsAndOutputs.hasCompiledSourcePath() &&
       Instance.getPrimarySourceFiles().empty()) {
@@ -1027,7 +999,7 @@ emitCompiledSourceForAllPrimaryInputsIfNeeded(CompilerInvocation &Invocation,
   }
 }
 
-static bool writeTBDIfNeeded(CompilerInvocation &Invocation,
+static bool writeTBDIfNeeded(const CompilerInvocation &Invocation,
                              CompilerInstance &Instance) {
   const auto &frontendOpts = Invocation.getFrontendOptions();
   const auto &tbdOpts = Invocation.getTBDGenOptions();
@@ -1055,7 +1027,7 @@ static std::string changeToLdAdd(StringRef ldHide) {
   return OS.str().str();
 }
 
-static bool writeLdAddCFileIfNeeded(CompilerInvocation &Invocation,
+static bool writeLdAddCFileIfNeeded(const CompilerInvocation &Invocation,
                                     CompilerInstance &Instance) {
   auto frontendOpts = Invocation.getFrontendOptions();
   if (!frontendOpts.InputsAndOutputs.isWholeModule())
@@ -1104,14 +1076,14 @@ static bool writeLdAddCFileIfNeeded(CompilerInvocation &Invocation,
 }
 
 static bool performCompileStepsPostSILGen(
-    CompilerInstance &Instance, CompilerInvocation &Invocation,
+    CompilerInstance &Instance, const CompilerInvocation &Invocation,
     std::unique_ptr<SILModule> SM, bool astGuaranteedToCorrespondToSIL,
     ModuleOrSourceFile MSF, const PrimarySpecificPaths &PSPs,
     bool moduleIsPublic, int &ReturnValue, FrontendObserver *observer,
     UnifiedStatsReporter *Stats);
 
 static bool
-performCompileStepsPostSema(CompilerInvocation &Invocation,
+performCompileStepsPostSema(const CompilerInvocation &Invocation,
                             CompilerInstance &Instance,
                             bool moduleIsPublic, int &ReturnValue,
                             FrontendObserver *observer,
@@ -1126,8 +1098,8 @@ performCompileStepsPostSema(CompilerInvocation &Invocation,
                                          ReturnValue, observer, Stats);
   }
 
-  SILOptions &SILOpts = Invocation.getSILOptions();
-  FrontendOptions &opts = Invocation.getFrontendOptions();
+  const SILOptions &SILOpts = Invocation.getSILOptions();
+  const FrontendOptions &opts = Invocation.getFrontendOptions();
   auto fileIsSIB = [](const FileUnit *File) -> bool {
     auto SASTF = dyn_cast<SerializedASTFile>(File);
     return SASTF && SASTF->isSIB();
@@ -1186,7 +1158,7 @@ performCompileStepsPostSema(CompilerInvocation &Invocation,
 
 /// Emits index data for all primary inputs, or the main module.
 static bool
-emitIndexData(CompilerInvocation &Invocation, CompilerInstance &Instance) {
+emitIndexData(const CompilerInvocation &Invocation, const CompilerInstance &Instance) {
   bool hadEmitIndexDataError = false;
   if (Instance.getPrimarySourceFiles().empty())
     return emitIndexDataIfNeeded(nullptr, Invocation, Instance);
@@ -1203,7 +1175,7 @@ emitIndexData(CompilerInvocation &Invocation, CompilerInstance &Instance) {
 /// `-typecheck`, but skipped for any mode that runs SIL diagnostics if there's
 /// an error found there (to get those diagnostics back to the user faster).
 static bool emitAnyWholeModulePostTypeCheckSupplementaryOutputs(
-    CompilerInstance &Instance, CompilerInvocation &Invocation,
+    CompilerInstance &Instance, const CompilerInvocation &Invocation,
     bool moduleIsPublic) {
   const FrontendOptions &opts = Invocation.getFrontendOptions();
 
@@ -1240,7 +1212,7 @@ static bool emitAnyWholeModulePostTypeCheckSupplementaryOutputs(
 ///                 mode is NoVerify and there were no errors.
 /// \returns true on error
 static bool performCompile(CompilerInstance &Instance,
-                           CompilerInvocation &Invocation,
+                           const CompilerInvocation &Invocation,
                            ArrayRef<const char *> Args,
                            int &ReturnValue,
                            FrontendObserver *observer,
@@ -1371,23 +1343,8 @@ static bool performCompile(CompilerInstance &Instance,
                                      ReturnValue, observer, Stats);
 }
 
-/// Get the main source file's private discriminator and attach it to
-/// the compile unit's flags.
-static void setPrivateDiscriminatorIfNeeded(IRGenOptions &IRGenOpts,
-                                            ModuleOrSourceFile MSF) {
-  if (IRGenOpts.DebugInfoLevel == IRGenDebugInfoLevel::None ||
-      !MSF.is<SourceFile *>())
-    return;
-  Identifier PD = MSF.get<SourceFile *>()->getPrivateDiscriminator();
-  if (!PD.empty()) {
-    if (!IRGenOpts.DebugFlags.empty())
-      IRGenOpts.DebugFlags += " ";
-    IRGenOpts.DebugFlags += ("-private-discriminator " + PD.str()).str();
-  }
-}
-
 static bool serializeSIB(SILModule *SM, const PrimarySpecificPaths &PSPs,
-                         ASTContext &Context, ModuleOrSourceFile MSF) {
+                         const ASTContext &Context, ModuleOrSourceFile MSF) {
   const std::string &moduleOutputPath =
       PSPs.SupplementaryOutputs.ModuleOutputPath;
   assert(!moduleOutputPath.empty() && "must have an output path");
@@ -1401,7 +1358,8 @@ static bool serializeSIB(SILModule *SM, const PrimarySpecificPaths &PSPs,
   return Context.hadError();
 }
 
-static void generateIR(IRGenOptions &IRGenOpts, std::unique_ptr<SILModule> SM,
+static void generateIR(const IRGenOptions &IRGenOpts,
+                       std::unique_ptr<SILModule> SM,
                        const PrimarySpecificPaths &PSPs,
                        StringRef OutputFilename, ModuleOrSourceFile MSF,
                        std::unique_ptr<llvm::Module> &IRModule,
@@ -1414,6 +1372,7 @@ static void generateIR(IRGenOptions &IRGenOpts, std::unique_ptr<SILModule> SM,
   IRModule = MSF.is<SourceFile *>()
                  ? performIRGeneration(IRGenOpts, *MSF.get<SourceFile *>(),
                                        std::move(SM), OutputFilename, PSPs,
+                                       MSF.get<SourceFile *>()->getPrivateDiscriminator().str(),
                                        LLVMContext, &HashGlobal,
                                        &LinkerDirectives)
                  : performIRGeneration(IRGenOpts, MSF.get<ModuleDecl *>(),
@@ -1422,22 +1381,17 @@ static void generateIR(IRGenOptions &IRGenOpts, std::unique_ptr<SILModule> SM,
                                        &HashGlobal, &LinkerDirectives);
 }
 
-static bool processCommandLineAndRunImmediately(CompilerInvocation &Invocation,
+static bool processCommandLineAndRunImmediately(const CompilerInvocation &Invocation,
                                                 CompilerInstance &Instance,
-                                                std::unique_ptr<SILModule> SM,
+                                                std::unique_ptr<SILModule> &&SM,
                                                 ModuleOrSourceFile MSF,
                                                 FrontendObserver *observer,
                                                 int &ReturnValue) {
-  FrontendOptions &opts = Invocation.getFrontendOptions();
+  const FrontendOptions &opts = Invocation.getFrontendOptions();
   assert(!MSF.is<SourceFile *>() && "-i doesn't work in -primary-file mode");
-  IRGenOptions &IRGenOpts = Invocation.getIRGenOptions();
-  IRGenOpts.UseJIT = true;
-  IRGenOpts.DebugInfoLevel = IRGenDebugInfoLevel::Normal;
-  IRGenOpts.DebugInfoFormat = IRGenDebugInfoFormat::DWARF;
+  const IRGenOptions &IRGenOpts = Invocation.getIRGenOptions();
   const ProcessCmdLine &CmdLine =
       ProcessCmdLine(opts.ImmediateArgv.begin(), opts.ImmediateArgv.end());
-  Instance.setSILModule(std::move(SM));
-
 
   PrettyStackTraceStringAction trace(
       "running user code",
@@ -1445,11 +1399,12 @@ static bool processCommandLineAndRunImmediately(CompilerInvocation &Invocation,
                      : MSF.get<ModuleDecl *>()->getModuleFilename());
 
   ReturnValue =
-      RunImmediately(Instance, CmdLine, IRGenOpts, Invocation.getSILOptions());
+      RunImmediately(Instance, CmdLine, IRGenOpts, Invocation.getSILOptions(),
+                     std::move(SM));
   return Instance.getASTContext().hadError();
 }
 
-static bool validateTBDIfNeeded(CompilerInvocation &Invocation,
+static bool validateTBDIfNeeded(const CompilerInvocation &Invocation,
                                 ModuleOrSourceFile MSF,
                                 bool astGuaranteedToCorrespondToSIL,
                                 llvm::Module &IRModule) {
@@ -1488,7 +1443,7 @@ static bool validateTBDIfNeeded(CompilerInvocation &Invocation,
                            Invocation.getTBDGenOptions(), allSymbols);
 }
 
-static bool generateCode(CompilerInvocation &Invocation,
+static bool generateCode(const CompilerInvocation &Invocation,
                          CompilerInstance &Instance, StringRef OutputFilename,
                          llvm::Module *IRModule,
                          llvm::GlobalVariable *HashGlobal,
@@ -1518,7 +1473,7 @@ static bool generateCode(CompilerInvocation &Invocation,
                      EffectiveLanguageVersion, OutputFilename, Stats);
 }
 
-static void collectLinkerDirectives(CompilerInvocation &Invocation,
+static void collectLinkerDirectives(const CompilerInvocation &Invocation,
                                     ModuleOrSourceFile MSF,
                                     llvm::StringSet<> &Symbols) {
   auto tbdOpts = Invocation.getTBDGenOptions();
@@ -1530,7 +1485,7 @@ static void collectLinkerDirectives(CompilerInvocation &Invocation,
 }
 
 static bool performCompileStepsPostSILGen(
-    CompilerInstance &Instance, CompilerInvocation &Invocation,
+    CompilerInstance &Instance, const CompilerInvocation &Invocation,
     std::unique_ptr<SILModule> SM, bool astGuaranteedToCorrespondToSIL,
     ModuleOrSourceFile MSF, const PrimarySpecificPaths &PSPs,
     bool moduleIsPublic, int &ReturnValue, FrontendObserver *observer,
@@ -1538,9 +1493,9 @@ static bool performCompileStepsPostSILGen(
 
   FrontendOptions opts = Invocation.getFrontendOptions();
   FrontendOptions::ActionType Action = opts.RequestedAction;
-  ASTContext &Context = Instance.getASTContext();
-  SILOptions &SILOpts = Invocation.getSILOptions();
-  IRGenOptions &IRGenOpts = Invocation.getIRGenOptions();
+  const ASTContext &Context = Instance.getASTContext();
+  const SILOptions &SILOpts = Invocation.getSILOptions();
+  const IRGenOptions &IRGenOpts = Invocation.getIRGenOptions();
 
   Optional<BufferIndirectlyCausingDiagnosticRAII> ricd;
   if (auto *SF = MSF.dyn_cast<SourceFile *>())
@@ -1558,7 +1513,7 @@ static bool performCompileStepsPostSILGen(
   }
 
   if (Action == FrontendOptions::ActionType::EmitSIBGen) {
-    serializeSIB(SM.get(), PSPs, Instance.getASTContext(), MSF);
+    serializeSIB(SM.get(), PSPs, Context, MSF);
     return Context.hadError();
   }
 
@@ -1601,10 +1556,8 @@ static bool performCompileStepsPostSILGen(
   emitAnyWholeModulePostTypeCheckSupplementaryOutputs(Instance, Invocation,
                                                       moduleIsPublic);
 
-  setPrivateDiscriminatorIfNeeded(IRGenOpts, MSF);
-
   if (Action == FrontendOptions::ActionType::EmitSIB)
-    return serializeSIB(SM.get(), PSPs, Instance.getASTContext(), MSF);
+    return serializeSIB(SM.get(), PSPs, Context, MSF);
 
   {
     if (PSPs.haveModuleOrModuleDocOutputPaths()) {
@@ -1651,8 +1604,6 @@ static bool performCompileStepsPostSILGen(
   if (Action == FrontendOptions::ActionType::DumpTypeInfo)
     return performDumpTypeInfo(IRGenOpts, *SM, getGlobalLLVMContext());
 
-  // TODO: remove once the frontend understands what action it should perform
-  IRGenOpts.OutputKind = getOutputKind(Action);
   if (Action == FrontendOptions::ActionType::Immediate)
     return processCommandLineAndRunImmediately(
         Invocation, Instance, std::move(SM), MSF, observer, ReturnValue);
@@ -1693,7 +1644,7 @@ static bool performCompileStepsPostSILGen(
 
 static bool emitIndexDataIfNeeded(SourceFile *PrimarySourceFile,
                                   const CompilerInvocation &Invocation,
-                                  CompilerInstance &Instance) {
+                                  const CompilerInstance &Instance) {
   const FrontendOptions &opts = Invocation.getFrontendOptions();
 
   if (opts.IndexStorePath.empty())
@@ -1942,7 +1893,7 @@ createJSONFixItDiagnosticConsumerIfNeeded(
 }
 
 /// Print information about the selected target in JSON.
-static void printTargetInfo(CompilerInvocation &invocation,
+static void printTargetInfo(const CompilerInvocation &invocation,
                             llvm::raw_ostream &out) {
   out << "{\n";
 
diff --git a/lib/IRGen/GenObjC.cpp b/lib/IRGen/GenObjC.cpp
index e7aee4142c7..77ce2bedaed 100644
--- a/lib/IRGen/GenObjC.cpp
+++ b/lib/IRGen/GenObjC.cpp
@@ -919,8 +919,11 @@ static llvm::Constant *findSwiftAsObjCThunk(IRGenModule &IGM, SILDeclRef ref,
   assert(SILFn && "no IR function for swift-as-objc thunk");
   auto fn = IGM.getAddrOfSILFunction(SILFn, NotForDefinition);
   ApplyIRLinkage(IRLinkage::Internal).to(fn);
-  fn->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
-
+  // Don't add the unnamed_addr attribute: in some places Foundation is
+  // comparing ObjC method pointers. Therefore LLVM's function merging pass must
+  // not create aliases for identical functions, but create thunks.
+  // This can be ensured if ObjC methods are not created with the unnamed_addr
+  // attribute.
   return llvm::ConstantExpr::getBitCast(fn, IGM.Int8PtrTy);
 }
 
diff --git a/lib/IRGen/IRGen.cpp b/lib/IRGen/IRGen.cpp
index e672678fa50..e9c0c9235a9 100644
--- a/lib/IRGen/IRGen.cpp
+++ b/lib/IRGen/IRGen.cpp
@@ -153,7 +153,7 @@ static void addSanitizerCoveragePass(const PassManagerBuilder &Builder,
 
 std::tuple<llvm::TargetOptions, std::string, std::vector<std::string>,
            std::string>
-swift::getIRTargetOptions(IRGenOptions &Opts, ASTContext &Ctx) {
+swift::getIRTargetOptions(const IRGenOptions &Opts, ASTContext &Ctx) {
   // Things that maybe we should collect from the command line:
   //   - relocation model
   //   - code model
@@ -180,7 +180,8 @@ void setModuleFlags(IRGenModule &IGM) {
                         IRGenModule::swiftVersion);
 }
 
-void swift::performLLVMOptimizations(IRGenOptions &Opts, llvm::Module *Module,
+void swift::performLLVMOptimizations(const IRGenOptions &Opts,
+                                     llvm::Module *Module,
                                      llvm::TargetMachine *TargetMachine) {
   // Set up a pipeline.
   PassManagerBuilderWrapper PMBuilder(Opts);
@@ -346,7 +347,7 @@ public:
 
 /// Computes the MD5 hash of the llvm \p Module including the compiler version
 /// and options which influence the compilation.
-static void getHashOfModule(MD5::MD5Result &Result, IRGenOptions &Opts,
+static void getHashOfModule(MD5::MD5Result &Result, const IRGenOptions &Opts,
                             llvm::Module *Module,
                             llvm::TargetMachine *TargetMachine,
                             version::Version const& effectiveLanguageVersion) {
@@ -463,7 +464,7 @@ diagnoseSync(DiagnosticEngine *Diags, llvm::sys::Mutex *DiagMutex,
 
 /// Run the LLVM passes. In multi-threaded compilation this will be done for
 /// multiple LLVM modules in parallel.
-bool swift::performLLVM(IRGenOptions &Opts, DiagnosticEngine *Diags,
+bool swift::performLLVM(const IRGenOptions &Opts, DiagnosticEngine *Diags,
                         llvm::sys::Mutex *DiagMutex,
                         llvm::GlobalVariable *HashGlobal,
                         llvm::Module *Module,
@@ -651,7 +652,7 @@ bool swift::performLLVM(IRGenOptions &Opts, DiagnosticEngine *Diags,
 }
 
 std::unique_ptr<llvm::TargetMachine>
-swift::createTargetMachine(IRGenOptions &Opts, ASTContext &Ctx) {
+swift::createTargetMachine(const IRGenOptions &Opts, ASTContext &Ctx) {
   CodeGenOpt::Level OptLevel = Opts.shouldOptimize()
                                    ? CodeGenOpt::Default // -Os
                                    : CodeGenOpt::None;
@@ -703,7 +704,7 @@ swift::createTargetMachine(IRGenOptions &Opts, ASTContext &Ctx) {
   return std::unique_ptr<llvm::TargetMachine>(TargetMachine);
 }
 
-IRGenerator::IRGenerator(IRGenOptions &options, SILModule &module)
+IRGenerator::IRGenerator(const IRGenOptions &options, SILModule &module)
   : Opts(options), SIL(module), QueueIndex(0) {
 }
 
@@ -814,6 +815,7 @@ static void initLLVMModule(const IRGenModule &IGM, ModuleDecl &M) {
 std::pair<IRGenerator *, IRGenModule *>
 swift::irgen::createIRGenModule(SILModule *SILMod, StringRef OutputFilename,
                                 StringRef MainInputFilenameForDebugInfo,
+                                StringRef PrivateDiscriminator,
                                 llvm::LLVMContext &LLVMContext) {
 
   IRGenOptions Opts;
@@ -825,7 +827,8 @@ swift::irgen::createIRGenModule(SILModule *SILMod, StringRef OutputFilename,
   // Create the IR emitter.
   IRGenModule *IGM =
       new IRGenModule(*irgen, std::move(targetMachine), nullptr, LLVMContext,
-                      "", OutputFilename, MainInputFilenameForDebugInfo);
+                      "", OutputFilename, MainInputFilenameForDebugInfo,
+                      PrivateDiscriminator);
 
   initLLVMModule(*IGM, *SILMod->getSwiftModule());
 
@@ -861,9 +864,10 @@ static void runIRGenPreparePasses(SILModule &Module,
 /// Generates LLVM IR, runs the LLVM passes and produces the output file.
 /// All this is done in a single thread.
 static std::unique_ptr<llvm::Module>
-performIRGeneration(IRGenOptions &Opts, ModuleDecl *M,
+performIRGeneration(const IRGenOptions &Opts, ModuleDecl *M,
                     std::unique_ptr<SILModule> SILMod, StringRef ModuleName,
                     const PrimarySpecificPaths &PSPs,
+                    StringRef PrivateDiscriminator,
                     llvm::LLVMContext &LLVMContext, SourceFile *SF = nullptr,
                     llvm::GlobalVariable **outModuleHash = nullptr,
                     llvm::StringSet<> *linkerDirectives = nullptr) {
@@ -878,7 +882,8 @@ performIRGeneration(IRGenOptions &Opts, ModuleDecl *M,
   // Create the IR emitter.
   IRGenModule IGM(irgen, std::move(targetMachine), nullptr, LLVMContext,
                   ModuleName, PSPs.OutputFilename,
-                  PSPs.MainInputFilenameForDebugInfo);
+                  PSPs.MainInputFilenameForDebugInfo,
+                  PrivateDiscriminator);
 
   initLLVMModule(IGM, *SILMod->getSwiftModule());
 
@@ -1075,7 +1080,7 @@ struct LLVMCodeGenThreads {
 /// Generates LLVM IR, runs the LLVM passes and produces the output files.
 /// All this is done in multiple threads.
 static void performParallelIRGeneration(
-    IRGenOptions &Opts, swift::ModuleDecl *M, std::unique_ptr<SILModule> SILMod,
+    const IRGenOptions &Opts, swift::ModuleDecl *M, std::unique_ptr<SILModule> SILMod,
     StringRef ModuleName, int numThreads,
     ArrayRef<std::string> outputFilenames,
     llvm::StringSet<> *linkerDirectives) {
@@ -1125,7 +1130,8 @@ static void performParallelIRGeneration(
     // Create the IR emitter.
     IRGenModule *IGM =
         new IRGenModule(irgen, std::move(targetMachine), nextSF, *Context,
-                        ModuleName, *OutputIter++, nextSF->getFilename());
+                        ModuleName, *OutputIter++, nextSF->getFilename(),
+                        nextSF->getPrivateDiscriminator().str());
     IGMcreated = true;
 
     initLLVMModule(*IGM, *SILMod->getSwiftModule());
@@ -1268,7 +1274,7 @@ static void performParallelIRGeneration(
 }
 
 std::unique_ptr<llvm::Module> swift::performIRGeneration(
-    IRGenOptions &Opts, swift::ModuleDecl *M, std::unique_ptr<SILModule> SILMod,
+    const IRGenOptions &Opts, swift::ModuleDecl *M, std::unique_ptr<SILModule> SILMod,
     StringRef ModuleName, const PrimarySpecificPaths &PSPs,
     llvm::LLVMContext &LLVMContext,
     ArrayRef<std::string> parallelOutputFilenames,
@@ -1285,19 +1291,21 @@ std::unique_ptr<llvm::Module> swift::performIRGeneration(
     return nullptr;
   }
   return ::performIRGeneration(Opts, M, std::move(SILMod), ModuleName, PSPs,
-                               LLVMContext, nullptr, outModuleHash,
-                               LinkerDirectives);
+                               "", LLVMContext, nullptr,
+                               outModuleHash, LinkerDirectives);
 }
 
 std::unique_ptr<llvm::Module> swift::
-performIRGeneration(IRGenOptions &Opts, SourceFile &SF,
+performIRGeneration(const IRGenOptions &Opts, SourceFile &SF,
                     std::unique_ptr<SILModule> SILMod,
                     StringRef ModuleName, const PrimarySpecificPaths &PSPs,
+                    StringRef PrivateDiscriminator,
                     llvm::LLVMContext &LLVMContext,
                     llvm::GlobalVariable **outModuleHash,
                     llvm::StringSet<> *LinkerDirectives) {
   return ::performIRGeneration(Opts, SF.getParentModule(), std::move(SILMod),
-                               ModuleName, PSPs, LLVMContext, &SF,
+                               ModuleName, PSPs, PrivateDiscriminator,
+                               LLVMContext, &SF,
                                outModuleHash, LinkerDirectives);
 }
 
@@ -1317,7 +1325,7 @@ swift::createSwiftModuleObjectFile(SILModule &SILMod, StringRef Buffer,
   if (!targetMachine) return;
 
   IRGenModule IGM(irgen, std::move(targetMachine), nullptr, VMContext,
-                  OutputPath, OutputPath, "");
+                  OutputPath, OutputPath, "", "");
   initLLVMModule(IGM, *SILMod.getSwiftModule());
   auto *Ty = llvm::ArrayType::get(IGM.Int8Ty, Buffer.size());
   auto *Data =
@@ -1352,7 +1360,7 @@ swift::createSwiftModuleObjectFile(SILModule &SILMod, StringRef Buffer,
                 OutputPath);
 }
 
-bool swift::performLLVM(IRGenOptions &Opts, ASTContext &Ctx,
+bool swift::performLLVM(const IRGenOptions &Opts, ASTContext &Ctx,
                         llvm::Module *Module, StringRef OutputFilename,
                         UnifiedStatsReporter *Stats) {
   // Build TargetMachine.
diff --git a/lib/IRGen/IRGenDebugInfo.cpp b/lib/IRGen/IRGenDebugInfo.cpp
index 59a3b75da93..1e047b2060f 100644
--- a/lib/IRGen/IRGenDebugInfo.cpp
+++ b/lib/IRGen/IRGenDebugInfo.cpp
@@ -143,7 +143,8 @@ class IRGenDebugInfoImpl : public IRGenDebugInfo {
 public:
   IRGenDebugInfoImpl(const IRGenOptions &Opts, ClangImporter &CI,
                      IRGenModule &IGM, llvm::Module &M,
-                     StringRef MainOutputFilenameForDebugInfo);
+                     StringRef MainOutputFilenameForDebugInfo,
+                     StringRef PrivateDiscriminator);
   void finalize();
 
   void setCurrentLoc(IRBuilder &Builder, const SILDebugScope *DS,
@@ -1664,7 +1665,8 @@ private:
 IRGenDebugInfoImpl::IRGenDebugInfoImpl(const IRGenOptions &Opts,
                                        ClangImporter &CI, IRGenModule &IGM,
                                        llvm::Module &M,
-                                       StringRef MainOutputFilenameForDebugInfo)
+                                       StringRef MainOutputFilenameForDebugInfo,
+                                       StringRef PD)
     : Opts(Opts), CI(CI), SM(IGM.Context.SourceMgr), M(M), DBuilder(M),
       IGM(IGM), DebugPrefixMap(Opts.DebugPrefixMap) {
   assert(Opts.DebugInfoLevel > IRGenDebugInfoLevel::None &&
@@ -1678,7 +1680,6 @@ IRGenDebugInfoImpl::IRGenDebugInfoImpl(const IRGenOptions &Opts,
   unsigned Lang = llvm::dwarf::DW_LANG_Swift;
   std::string Producer = version::getSwiftFullVersion(
       IGM.Context.LangOpts.EffectiveLanguageVersion);
-  StringRef Flags = Opts.DebugFlags;
   unsigned Major, Minor;
   std::tie(Major, Minor) = version::getSwiftNumericVersion();
   unsigned MajorRuntimeVersion = Major;
@@ -1693,7 +1694,8 @@ IRGenDebugInfoImpl::IRGenDebugInfoImpl(const IRGenOptions &Opts,
 
   TheCU = DBuilder.createCompileUnit(
       Lang, MainFile,
-      Producer, Opts.shouldOptimize(), Flags, MajorRuntimeVersion, SplitName,
+      Producer, Opts.shouldOptimize(), Opts.getDebugFlags(PD),
+      MajorRuntimeVersion, SplitName,
       Opts.DebugInfoLevel > IRGenDebugInfoLevel::LineTables
           ? llvm::DICompileUnit::FullDebug
           : llvm::DICompileUnit::LineTablesOnly);
@@ -2356,9 +2358,11 @@ SILLocation::DebugLoc IRGenDebugInfoImpl::decodeSourceLoc(SourceLoc SL) {
 
 std::unique_ptr<IRGenDebugInfo> IRGenDebugInfo::createIRGenDebugInfo(
     const IRGenOptions &Opts, ClangImporter &CI, IRGenModule &IGM,
-    llvm::Module &M, StringRef MainOutputFilenameForDebugInfo) {
+    llvm::Module &M, StringRef MainOutputFilenameForDebugInfo,
+    StringRef PrivateDiscriminator) {
   return std::make_unique<IRGenDebugInfoImpl>(Opts, CI, IGM, M,
-                                               MainOutputFilenameForDebugInfo);
+                                              MainOutputFilenameForDebugInfo,
+                                              PrivateDiscriminator);
 }
 
 
diff --git a/lib/IRGen/IRGenDebugInfo.h b/lib/IRGen/IRGenDebugInfo.h
index 6b59daeaaf7..229a544b7ce 100644
--- a/lib/IRGen/IRGenDebugInfo.h
+++ b/lib/IRGen/IRGenDebugInfo.h
@@ -49,7 +49,8 @@ public:
   static std::unique_ptr<IRGenDebugInfo>
   createIRGenDebugInfo(const IRGenOptions &Opts, ClangImporter &CI,
                        IRGenModule &IGM, llvm::Module &M,
-                       StringRef MainOutputFilenameForDebugInfo);
+                       StringRef MainOutputFilenameForDebugInfo,
+                       StringRef PrivateDiscriminator);
   virtual ~IRGenDebugInfo();
 
   /// Finalize the llvm::DIBuilder owned by this object.
diff --git a/lib/IRGen/IRGenModule.cpp b/lib/IRGen/IRGenModule.cpp
index 49ed490b884..3ed07808b41 100644
--- a/lib/IRGen/IRGenModule.cpp
+++ b/lib/IRGen/IRGenModule.cpp
@@ -87,8 +87,9 @@ static llvm::PointerType *createStructPointerType(IRGenModule &IGM,
 
 static clang::CodeGenerator *createClangCodeGenerator(ASTContext &Context,
                                                  llvm::LLVMContext &LLVMContext,
-                                                      IRGenOptions &Opts,
-                                                      StringRef ModuleName) {
+                                                      const IRGenOptions &Opts,
+                                                      StringRef ModuleName,
+                                                      StringRef PD) {
   auto Loader = Context.getClangModuleLoader();
   auto *Importer = static_cast<ClangImporter*>(&*Loader);
   assert(Importer && "No clang module loader!");
@@ -119,13 +120,13 @@ static clang::CodeGenerator *createClangCodeGenerator(ASTContext &Context,
   case IRGenDebugInfoFormat::DWARF:
     CGO.DebugCompilationDir = Opts.DebugCompilationDir;
     CGO.DwarfVersion = Opts.DWARFVersion;
-    CGO.DwarfDebugFlags = Opts.DebugFlags;
+    CGO.DwarfDebugFlags = Opts.getDebugFlags(PD);
     break;
   case IRGenDebugInfoFormat::CodeView:
     CGO.EmitCodeView = true;
     CGO.DebugCompilationDir = Opts.DebugCompilationDir;
     // This actually contains the debug flags for codeview.
-    CGO.DwarfDebugFlags = Opts.DebugFlags;
+    CGO.DwarfDebugFlags = Opts.getDebugFlags(PD);
     break;
   }
 
@@ -144,10 +145,11 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
                          std::unique_ptr<llvm::TargetMachine> &&target,
                          SourceFile *SF, llvm::LLVMContext &LLVMContext,
                          StringRef ModuleName, StringRef OutputFilename,
-                         StringRef MainInputFilenameForDebugInfo)
+                         StringRef MainInputFilenameForDebugInfo,
+                         StringRef PrivateDiscriminator)
     : IRGen(irgen), Context(irgen.SIL.getASTContext()),
       ClangCodeGen(createClangCodeGenerator(Context, LLVMContext, irgen.Opts,
-                                            ModuleName)),
+                                            ModuleName, PrivateDiscriminator)),
       Module(*ClangCodeGen->GetModule()), LLVMContext(Module.getContext()),
       DataLayout(irgen.getClangDataLayout()),
       Triple(irgen.getEffectiveClangTriple()), TargetMachine(std::move(target)),
@@ -491,7 +493,8 @@ IRGenModule::IRGenModule(IRGenerator &irgen,
   if (opts.DebugInfoLevel > IRGenDebugInfoLevel::None)
     DebugInfo = IRGenDebugInfo::createIRGenDebugInfo(IRGen.Opts, *CI, *this,
                                                      Module,
-                                                 MainInputFilenameForDebugInfo);
+                                                 MainInputFilenameForDebugInfo,
+                                                     PrivateDiscriminator);
 
   initClangTypeConverter();
 
diff --git a/lib/IRGen/IRGenModule.h b/lib/IRGen/IRGenModule.h
index 7f7e4a78896..2e88aee79eb 100644
--- a/lib/IRGen/IRGenModule.h
+++ b/lib/IRGen/IRGenModule.h
@@ -194,7 +194,7 @@ enum RequireMetadata_t : bool {
 /// IRGenModules - one for each LLVM module (= one for each input/output file).
 class IRGenerator {
 public:
-  IRGenOptions &Opts;
+  const IRGenOptions &Opts;
 
   SILModule &SIL;
 
@@ -298,7 +298,7 @@ private:
   
   friend class CurrentIGMPtr;  
 public:
-  explicit IRGenerator(IRGenOptions &opts, SILModule &module);
+  explicit IRGenerator(const IRGenOptions &opts, SILModule &module);
 
   /// Attempt to create an llvm::TargetMachine for the current target.
   std::unique_ptr<llvm::TargetMachine> createTargetMachine();
@@ -1225,14 +1225,15 @@ public:
   IRGenModule(IRGenerator &irgen, std::unique_ptr<llvm::TargetMachine> &&target,
               SourceFile *SF, llvm::LLVMContext &LLVMContext,
               StringRef ModuleName, StringRef OutputFilename,
-              StringRef MainInputFilenameForDebugInfo);
+              StringRef MainInputFilenameForDebugInfo,
+              StringRef PrivateDiscriminator);
 
   /// The constructor used when we just need an IRGenModule for type lowering.
   IRGenModule(IRGenerator &irgen, std::unique_ptr<llvm::TargetMachine> &&target,
               llvm::LLVMContext &LLVMContext)
     : IRGenModule(irgen, std::move(target), /*SF=*/nullptr, LLVMContext,
                   "<fake module name>", "<fake output filename>",
-                  "<fake main input filename>") {}
+                  "<fake main input filename>", "") {}
 
   ~IRGenModule();
 
diff --git a/lib/IRGen/MetadataRequest.cpp b/lib/IRGen/MetadataRequest.cpp
index 88e2fc4033f..5b9f33dbb2c 100644
--- a/lib/IRGen/MetadataRequest.cpp
+++ b/lib/IRGen/MetadataRequest.cpp
@@ -2138,10 +2138,7 @@ static bool shouldAccessByMangledName(IRGenModule &IGM, CanType type) {
   if (auto nom = dyn_cast<NominalType>(type)) {
     if (!isa<ProtocolDecl>(nom->getDecl())
         && (!nom->getDecl()->isGenericContext()
-            || nom->getDecl()->getGenericSignature()->areAllParamsConcrete())
-        && (!nom->getClassOrBoundGenericClass()
-            || !nom->getClassOrBoundGenericClass()->hasClangNode()
-            || nom->getClassOrBoundGenericClass()->isForeign())) {
+            || nom->getDecl()->getGenericSignature()->areAllParamsConcrete())) {
       return false;
     }
   }
diff --git a/lib/IRGen/TypeLayoutDumper.cpp b/lib/IRGen/TypeLayoutDumper.cpp
index 49b8e52f4aa..614416956eb 100644
--- a/lib/IRGen/TypeLayoutDumper.cpp
+++ b/lib/IRGen/TypeLayoutDumper.cpp
@@ -152,7 +152,7 @@ void TypeLayoutDumper::write(ArrayRef<ModuleDecl *> AllModules,
   }
 }
 
-bool swift::performDumpTypeInfo(IRGenOptions &Opts,
+bool swift::performDumpTypeInfo(const IRGenOptions &Opts,
                                 SILModule &SILMod,
                                 llvm::LLVMContext &LLVMContext) {
   auto &Ctx = SILMod.getASTContext();
diff --git a/lib/Immediate/Immediate.cpp b/lib/Immediate/Immediate.cpp
index b6554d9ea45..4037c9efabf 100644
--- a/lib/Immediate/Immediate.cpp
+++ b/lib/Immediate/Immediate.cpp
@@ -220,7 +220,7 @@ bool swift::immediate::linkLLVMModules(llvm::Module *Module,
 }
 
 bool swift::immediate::autolinkImportedModules(ModuleDecl *M,
-                                               IRGenOptions &IRGenOpts) {
+                                               const IRGenOptions &IRGenOpts) {
   // Perform autolinking.
   SmallVector<LinkLibrary, 4> AllLinkLibraries(IRGenOpts.LinkLibraries);
   auto addLinkLibrary = [&](LinkLibrary linkLib) {
@@ -234,8 +234,11 @@ bool swift::immediate::autolinkImportedModules(ModuleDecl *M,
   return false;
 }
 
-int swift::RunImmediately(CompilerInstance &CI, const ProcessCmdLine &CmdLine,
-                          IRGenOptions &IRGenOpts, const SILOptions &SILOpts) {
+int swift::RunImmediately(CompilerInstance &CI,
+                          const ProcessCmdLine &CmdLine,
+                          const IRGenOptions &IRGenOpts,
+                          const SILOptions &SILOpts,
+                          std::unique_ptr<SILModule> &&SM) {
   ASTContext &Context = CI.getASTContext();
   
   // IRGen the main module.
@@ -244,7 +247,7 @@ int swift::RunImmediately(CompilerInstance &CI, const ProcessCmdLine &CmdLine,
   // FIXME: We shouldn't need to use the global context here, but
   // something is persisting across calls to performIRGeneration.
   auto ModuleOwner = performIRGeneration(
-      IRGenOpts, swiftModule, CI.takeSILModule(), swiftModule->getName().str(),
+      IRGenOpts, swiftModule, std::move(SM), swiftModule->getName().str(),
       PSPs, getGlobalLLVMContext(), ArrayRef<std::string>());
   auto *Module = ModuleOwner.get();
 
diff --git a/lib/Immediate/ImmediateImpl.h b/lib/Immediate/ImmediateImpl.h
index a309385910b..904e09691a4 100644
--- a/lib/Immediate/ImmediateImpl.h
+++ b/lib/Immediate/ImmediateImpl.h
@@ -44,7 +44,7 @@ bool tryLoadLibraries(ArrayRef<LinkLibrary> LinkLibraries,
                       DiagnosticEngine &Diags);
 bool linkLLVMModules(llvm::Module *Module,
                      std::unique_ptr<llvm::Module> SubModule);
-bool autolinkImportedModules(ModuleDecl *M, IRGenOptions &IRGenOpts);
+bool autolinkImportedModules(ModuleDecl *M, const IRGenOptions &IRGenOpts);
 
 } // end namespace immediate
 } // end namespace swift
diff --git a/lib/RemoteAST/RemoteAST.cpp b/lib/RemoteAST/RemoteAST.cpp
index 9b264e8665e..943a1dad7ba 100644
--- a/lib/RemoteAST/RemoteAST.cpp
+++ b/lib/RemoteAST/RemoteAST.cpp
@@ -59,7 +59,7 @@ namespace {
 
 /// A "minimal" class for querying IRGen.
 struct IRGenContext {
-  IRGenOptions IROpts;
+  const IRGenOptions IROpts;
   SILOptions SILOpts;
   Lowering::TypeConverter TC;
   std::unique_ptr<SILModule> SILMod;
diff --git a/lib/SIL/SILDeclRef.cpp b/lib/SIL/SILDeclRef.cpp
index c78e6674b15..b5244327851 100644
--- a/lib/SIL/SILDeclRef.cpp
+++ b/lib/SIL/SILDeclRef.cpp
@@ -958,31 +958,52 @@ SubclassScope SILDeclRef::getSubclassScope() const {
   if (!isa<AbstractFunctionDecl>(decl))
     return SubclassScope::NotApplicable;
 
-  // If this declaration is a function which goes into a vtable, then it's
-  // symbol must be as visible as its class, because derived classes have to put
-  // all less visible methods of the base class into their vtables.
+  DeclContext *context = decl->getDeclContext();
+
+  // Only methods in non-final classes go in the vtable.
+  auto *classType = dyn_cast<ClassDecl>(context);
+  if (!classType || classType->isFinal())
+    return SubclassScope::NotApplicable;
+
+  // If a method appears in the vtable of a class, we must give it's symbol
+  // special consideration when computing visibility because the SIL-level
+  // linkage does not map to the symbol's visibility in a straightforward
+  // way.
+  //
+  // In particular, the rules are:
+  // - If the class metadata is not resilient, then all method symbols must
+  //   be visible from any translation unit where a subclass might be defined,
+  //   because the subclass metadata will re-emit all vtable entries.
+  //
+  // - For resilient classes, we do the opposite: generally, a method's symbol
+  //   can be hidden from other translation units, because we want to enforce
+  //   that resilient access patterns are used for method calls and overrides.
+  //
+  //   Constructors and final methods are the exception here, because they can
+  //   be called directly.
+
+  // FIXME: This is too narrow. Any class with resilient metadata should
+  // probably have this, at least for method overrides that don't add new
+  // vtable entries.
+  bool isResilientClass = classType->isResilient();
 
   if (auto *CD = dyn_cast<ConstructorDecl>(decl)) {
+    if (isResilientClass)
+      return SubclassScope::NotApplicable;
     // Initializing entry points do not appear in the vtable.
     if (kind == SILDeclRef::Kind::Initializer)
       return SubclassScope::NotApplicable;
-    // Non-required convenience inits do not apper in the vtable.
+    // Non-required convenience inits do not appear in the vtable.
     if (!CD->isRequired() && !CD->isDesignatedInit())
       return SubclassScope::NotApplicable;
   } else if (isa<DestructorDecl>(decl)) {
-    // Detructors do not appear in the vtable.
+    // Destructors do not appear in the vtable.
     return SubclassScope::NotApplicable;
   } else {
     assert(isa<FuncDecl>(decl));
   }
 
-  DeclContext *context = decl->getDeclContext();
-
-  // Methods from extensions don't go in the vtable.
-  if (isa<ExtensionDecl>(context))
-    return SubclassScope::NotApplicable;
-
-  // Various forms of thunks don't either.
+  // Various forms of thunks don't go in the vtable.
   if (isThunk() || isForeign)
     return SubclassScope::NotApplicable;
 
@@ -990,35 +1011,41 @@ SubclassScope SILDeclRef::getSubclassScope() const {
   if (isDefaultArgGenerator())
     return SubclassScope::NotApplicable;
 
-  // Only methods in non-final classes go in the vtable.
-  auto *classType = context->getSelfClassDecl();
-  if (!classType || classType->isFinal())
-    return SubclassScope::NotApplicable;
+  if (decl->isFinal()) {
+    // Final methods only go in the vtable if they override something.
+    if (!decl->getOverriddenDecl())
+      return SubclassScope::NotApplicable;
 
-  // Final methods only go in the vtable if they override something.
-  if (decl->isFinal() && !decl->getOverriddenDecl())
-    return SubclassScope::NotApplicable;
+    // In the resilient case, we're going to be making symbols _less_
+    // visible, so make sure we stop now; final methods can always be
+    // called directly.
+    if (isResilientClass)
+      return SubclassScope::Internal;
+  }
 
   assert(decl->getEffectiveAccess() <= classType->getEffectiveAccess() &&
          "class must be as visible as its members");
 
-  // FIXME: This is too narrow. Any class with resilient metadata should
-  // probably have this, at least for method overrides that don't add new
-  // vtable entries.
-  if (classType->isResilient()) {
-    if (isa<ConstructorDecl>(decl))
-      return SubclassScope::NotApplicable;
+  if (isResilientClass) {
+    // The symbol should _only_ be reached via the vtable, so we're
+    // going to make it hidden.
     return SubclassScope::Resilient;
   }
 
   switch (classType->getEffectiveAccess()) {
   case AccessLevel::Private:
   case AccessLevel::FilePrivate:
+    // If the class is private, it can only be subclassed from the same
+    // SILModule, so we don't need to do anything.
     return SubclassScope::NotApplicable;
   case AccessLevel::Internal:
   case AccessLevel::Public:
+    // If the class is internal or public, it can only be subclassed from
+    // the same AST Module, but possibly a different SILModule.
     return SubclassScope::Internal;
   case AccessLevel::Open:
+    // If the class is open, it can be subclassed from a different
+    // AST Module. All method symbols are public.
     return SubclassScope::External;
   }
 
diff --git a/lib/SIL/SILModule.cpp b/lib/SIL/SILModule.cpp
index 6b2f749aeb5..6b022676ca2 100644
--- a/lib/SIL/SILModule.cpp
+++ b/lib/SIL/SILModule.cpp
@@ -90,7 +90,7 @@ class SILModule::SerializationCallback final
 };
 
 SILModule::SILModule(ModuleDecl *SwiftModule, TypeConverter &TC,
-                     SILOptions &Options, const DeclContext *associatedDC,
+                     const SILOptions &Options, const DeclContext *associatedDC,
                      bool wholeModule)
     : TheSwiftModule(SwiftModule),
       AssociatedDeclContext(associatedDC),
@@ -120,7 +120,7 @@ SILModule::~SILModule() {
 }
 
 std::unique_ptr<SILModule>
-SILModule::createEmptyModule(ModuleDecl *M, TypeConverter &TC, SILOptions &Options,
+SILModule::createEmptyModule(ModuleDecl *M, TypeConverter &TC, const SILOptions &Options,
                              bool WholeModule) {
   return std::unique_ptr<SILModule>(
       new SILModule(M, TC, Options, M, WholeModule));
diff --git a/lib/SILGen/SILGen.cpp b/lib/SILGen/SILGen.cpp
index b87b9521dbf..888aadc02cf 100644
--- a/lib/SILGen/SILGen.cpp
+++ b/lib/SILGen/SILGen.cpp
@@ -49,15 +49,15 @@ using namespace Lowering;
 
 SILGenModule::SILGenModule(SILModule &M, ModuleDecl *SM)
     : M(M), Types(M.Types), SwiftModule(SM), TopLevelSGF(nullptr) {
-  SILOptions &Opts = M.getOptions();
+  const SILOptions &Opts = M.getOptions();
   if (!Opts.UseProfile.empty()) {
     auto ReaderOrErr = llvm::IndexedInstrProfReader::create(Opts.UseProfile);
     if (auto E = ReaderOrErr.takeError()) {
       diagnose(SourceLoc(), diag::profile_read_error, Opts.UseProfile,
                llvm::toString(std::move(E)));
-      Opts.UseProfile.erase();
+    } else {
+      M.setPGOReader(std::move(ReaderOrErr.get()));
     }
-    M.setPGOReader(std::move(ReaderOrErr.get()));
   }
 }
 
@@ -1691,7 +1691,7 @@ void SILGenModule::emitSourceFile(SourceFile *sf) {
 
 std::unique_ptr<SILModule>
 SILModule::constructSIL(ModuleDecl *mod, TypeConverter &tc,
-                        SILOptions &options, FileUnit *SF) {
+                        const SILOptions &options, FileUnit *SF) {
   FrontendStatsTracer tracer(mod->getASTContext().Stats, "SILGen");
   const DeclContext *DC;
   if (SF) {
@@ -1751,12 +1751,12 @@ SILModule::constructSIL(ModuleDecl *mod, TypeConverter &tc,
 
 std::unique_ptr<SILModule>
 swift::performSILGeneration(ModuleDecl *mod, Lowering::TypeConverter &tc,
-                            SILOptions &options) {
+                            const SILOptions &options) {
   return SILModule::constructSIL(mod, tc, options, nullptr);
 }
 
 std::unique_ptr<SILModule>
 swift::performSILGeneration(FileUnit &sf, Lowering::TypeConverter &tc,
-                            SILOptions &options) {
+                            const SILOptions &options) {
   return SILModule::constructSIL(sf.getParentModule(), tc, options, &sf);
 }
diff --git a/lib/SILGen/SILGenBridging.cpp b/lib/SILGen/SILGenBridging.cpp
index 873ef443695..9ecb35559c5 100644
--- a/lib/SILGen/SILGenBridging.cpp
+++ b/lib/SILGen/SILGenBridging.cpp
@@ -730,7 +730,7 @@ static ManagedValue emitNativeToCBridgedNonoptionalValue(SILGenFunction &SGF,
                                  nativeType);
 
     // Put the value into memory if necessary.
-    assert(v.getType().isTrivial(SGF.F) || v.hasCleanup());
+    assert(v.getOwnershipKind() == ValueOwnershipKind::None || v.hasCleanup());
     SILModuleConventions silConv(SGF.SGM.M);
     // bridgeAnything always takes an indirect argument as @in.
     // Since we don't have the SIL type here, check the current SIL stage/mode
diff --git a/lib/SILGen/SILGenBuilder.cpp b/lib/SILGen/SILGenBuilder.cpp
index 7815383d495..503e6d6d9b5 100644
--- a/lib/SILGen/SILGenBuilder.cpp
+++ b/lib/SILGen/SILGenBuilder.cpp
@@ -669,8 +669,7 @@ ManagedValue SILGenBuilder::createStore(SILLocation loc, ManagedValue value,
                                         SILValue address,
                                         StoreOwnershipQualifier qualifier) {
   CleanupCloner cloner(*this, value);
-  if (value.getType().isTrivial(SGF.F) ||
-      value.getOwnershipKind() == ValueOwnershipKind::None)
+  if (value.getOwnershipKind() == ValueOwnershipKind::None)
     qualifier = StoreOwnershipQualifier::Trivial;
   createStore(loc, value.forward(SGF), address, qualifier);
   return cloner.clone(address);
diff --git a/lib/SILGen/SILGenFunction.h b/lib/SILGen/SILGenFunction.h
index 1026c859ab0..f0a4c9d7646 100644
--- a/lib/SILGen/SILGenFunction.h
+++ b/lib/SILGen/SILGenFunction.h
@@ -492,7 +492,7 @@ public:
   SILFunction &getFunction() { return F; }
   SILModule &getModule() { return F.getModule(); }
   SILGenBuilder &getBuilder() { return B; }
-  SILOptions &getOptions() { return getModule().getOptions(); }
+  const SILOptions &getOptions() { return getModule().getOptions(); }
 
   // Returns the type expansion context for types in this function.
   TypeExpansionContext getTypeExpansionContext() {
diff --git a/lib/Sema/CSBindings.cpp b/lib/Sema/CSBindings.cpp
index b7b5cbf4b09..acd726261f6 100644
--- a/lib/Sema/CSBindings.cpp
+++ b/lib/Sema/CSBindings.cpp
@@ -21,6 +21,66 @@
 using namespace swift;
 using namespace constraints;
 
+void ConstraintSystem::inferTransitiveSupertypeBindings(
+    const llvm::SmallDenseMap<TypeVariableType *, PotentialBindings>
+        &inferredBindings,
+    PotentialBindings &bindings) {
+  auto *typeVar = bindings.TypeVar;
+
+  llvm::SmallVector<Constraint *, 4> subtypeOf;
+  // First, let's collect all of the `subtype` constraints associated
+  // with this type variable.
+  llvm::copy_if(bindings.Sources, std::back_inserter(subtypeOf),
+                [&](const Constraint *constraint) -> bool {
+                  if (constraint->getKind() != ConstraintKind::Subtype)
+                    return false;
+
+                  auto rhs = simplifyType(constraint->getSecondType());
+                  return rhs->getAs<TypeVariableType>() == typeVar;
+                });
+
+  if (subtypeOf.empty())
+    return;
+
+  // We need to make sure that there are no duplicate bindings in the
+  // set, other we'll produce multiple identical solutions.
+  llvm::SmallPtrSet<CanType, 4> existingTypes;
+  for (const auto &binding : bindings.Bindings)
+    existingTypes.insert(binding.BindingType->getCanonicalType());
+
+  for (auto *constraint : subtypeOf) {
+    auto *tv =
+        simplifyType(constraint->getFirstType())->getAs<TypeVariableType>();
+    if (!tv)
+      continue;
+
+    auto relatedBindings = inferredBindings.find(tv);
+    if (relatedBindings == inferredBindings.end())
+      continue;
+
+    for (auto &binding : relatedBindings->getSecond().Bindings) {
+      // We need the binding kind for the potential binding to
+      // either be Exact or Supertypes in order for it to make sense
+      // to add Supertype bindings based on the relationship between
+      // our type variables.
+      if (binding.Kind != AllowedBindingKind::Exact &&
+          binding.Kind != AllowedBindingKind::Supertypes)
+        continue;
+
+      auto type = binding.BindingType;
+
+      if (!existingTypes.insert(type->getCanonicalType()).second)
+        continue;
+
+      if (ConstraintSystem::typeVarOccursInType(typeVar, type))
+        continue;
+
+      bindings.addPotentialBinding(
+          binding.withSameSource(type, AllowedBindingKind::Supertypes));
+    }
+  }
+}
+
 Optional<ConstraintSystem::PotentialBindings>
 ConstraintSystem::determineBestBindings() {
   // Look for potential type variable bindings.
@@ -44,46 +104,8 @@ ConstraintSystem::determineBestBindings() {
       continue;
 
     auto &bindings = cachedBindings->getSecond();
-    // All of the relevant relational constraints associated with
-    // current type variable should be recored by its potential bindings.
-    for (auto *constraint : bindings.Sources) {
-      if (constraint->getKind() != ConstraintKind::Subtype)
-        continue;
 
-      auto lhs = simplifyType(constraint->getFirstType());
-      auto rhs = simplifyType(constraint->getSecondType());
-
-      // We are only interested in 'subtype' constraints which have
-      // type variable on the left-hand side.
-      if (rhs->getAs<TypeVariableType>() != typeVar)
-        continue;
-
-      auto *tv = lhs->getAs<TypeVariableType>();
-      if (!tv)
-        continue;
-
-      auto relatedBindings = cache.find(tv);
-      if (relatedBindings == cache.end())
-        continue;
-
-      for (auto &binding : relatedBindings->getSecond().Bindings) {
-        // We need the binding kind for the potential binding to
-        // either be Exact or Supertypes in order for it to make sense
-        // to add Supertype bindings based on the relationship between
-        // our type variables.
-        if (binding.Kind != AllowedBindingKind::Exact &&
-            binding.Kind != AllowedBindingKind::Supertypes)
-          continue;
-
-        auto type = binding.BindingType;
-
-        if (ConstraintSystem::typeVarOccursInType(typeVar, type))
-          continue;
-
-        bindings.addPotentialBinding(
-            binding.withSameSource(type, AllowedBindingKind::Supertypes));
-      }
-    }
+    inferTransitiveSupertypeBindings(cache, bindings);
 
     if (getASTContext().TypeCheckerOpts.DebugConstraintSolver) {
       auto &log = getASTContext().TypeCheckerDebug->getStream();
diff --git a/lib/Sema/CSDiag.cpp b/lib/Sema/CSDiag.cpp
index c100cc30c0a..acb50536c10 100644
--- a/lib/Sema/CSDiag.cpp
+++ b/lib/Sema/CSDiag.cpp
@@ -2303,19 +2303,3 @@ void FailureDiagnosis::diagnoseAmbiguity(Expr *E) {
   diagnose(E->getLoc(), diag::type_of_expression_is_ambiguous)
     .highlight(E->getSourceRange());
 }
-
-/// If an UnresolvedDotExpr, SubscriptMember, etc has been resolved by the
-/// constraint system, return the decl that it references.
-ValueDecl *ConstraintSystem::findResolvedMemberRef(ConstraintLocator *locator) {
-  // See if we have a resolution for this member.
-  auto overload = findSelectedOverloadFor(locator);
-  if (!overload)
-    return nullptr;
-
-  // We only want to handle the simplest decl binding.
-  auto choice = overload->choice;
-  if (choice.getKind() != OverloadChoiceKind::Decl)
-    return nullptr;
-
-  return choice.getDecl();
-}
diff --git a/lib/Sema/ConstraintSystem.cpp b/lib/Sema/ConstraintSystem.cpp
index aefad4f372b..904a9222a9e 100644
--- a/lib/Sema/ConstraintSystem.cpp
+++ b/lib/Sema/ConstraintSystem.cpp
@@ -3940,3 +3940,19 @@ Expr *ConstraintSystem::buildAutoClosureExpr(Expr *expr,
   cacheExprTypes(result);
   return result;
 }
+
+/// If an UnresolvedDotExpr, SubscriptMember, etc has been resolved by the
+/// constraint system, return the decl that it references.
+ValueDecl *ConstraintSystem::findResolvedMemberRef(ConstraintLocator *locator) {
+  // See if we have a resolution for this member.
+  auto overload = findSelectedOverloadFor(locator);
+  if (!overload)
+    return nullptr;
+
+  // We only want to handle the simplest decl binding.
+  auto choice = overload->choice;
+  if (choice.getKind() != OverloadChoiceKind::Decl)
+    return nullptr;
+
+  return choice.getDecl();
+}
diff --git a/lib/Sema/ConstraintSystem.h b/lib/Sema/ConstraintSystem.h
index 4e4610ea32f..75d1aad3ca7 100644
--- a/lib/Sema/ConstraintSystem.h
+++ b/lib/Sema/ConstraintSystem.h
@@ -3761,6 +3761,22 @@ private:
       bool &addOptionalSupertypeBindings) const;
   PotentialBindings getPotentialBindings(TypeVariableType *typeVar) const;
 
+  /// Detect `subtype` relationship between two type variables and
+  /// attempt to infer supertype bindings transitively e.g.
+  ///
+  /// Given A <: T1 <: T2 transitively A <: T2
+  ///
+  /// Which gives us a new (superclass A) binding for T2 as well as T1.
+  ///
+  /// \param inferredBindings The set of all bindings inferred for type
+  /// variables in the workset.
+  /// \param bindings The type variable we aim to infer new supertype
+  /// bindings for.
+  void inferTransitiveSupertypeBindings(
+      const llvm::SmallDenseMap<TypeVariableType *, PotentialBindings>
+          &inferredBindings,
+      PotentialBindings &bindings);
+
 private:
   /// Add a constraint to the constraint system.
   SolutionKind addConstraintImpl(ConstraintKind kind, Type first, Type second,
diff --git a/test/Driver/autolink-force-load-no-comdat.swift b/test/Driver/autolink-force-load-no-comdat.swift
index c4dc53a4734..f87d27a0337 100644
--- a/test/Driver/autolink-force-load-no-comdat.swift
+++ b/test/Driver/autolink-force-load-no-comdat.swift
@@ -2,7 +2,7 @@
 // RUN: not %swiftc_driver -autolink-force-load -incremental %s 2>&1 | %FileCheck -check-prefix=AUTOLINK_FORCE_LOAD %s
 
 // MACHO targets do not support COMDAT
-// REQUIRES-ANY: OS=macosx, OS=tvos, OS=watchos, OS=ios
+// REQUIRES: OS=macosx || OS=tvos || OS=watchos || OS=ios
 
 // AUTOLINK_FORCE_LOAD: error: '-autolink-force-load' is not supported with '-incremental'
 
diff --git a/test/Driver/multi-threaded.swift b/test/Driver/multi-threaded.swift
index 76e33545bbb..84a15e5c6d5 100644
--- a/test/Driver/multi-threaded.swift
+++ b/test/Driver/multi-threaded.swift
@@ -55,9 +55,9 @@
 // EXEC: -frontend
 // EXEC-DAG: -num-threads 4
 // EXEC-DAG: {{[^ ]*[/\\]}}Inputs{{/|\\\\}}main.swift{{"?}} {{[^ ]*[/\\]}}multi-threaded.swift 
-// EXEC-DAG:  -o {{.*te?mp.*[/\\]}}main{{[^ ]*}}.o{{"?}} -o {{.*te?mp.*[/\\]}}multi-threaded{{[^ ]*}}.o
+// EXEC-DAG:  -o {{.*[tT]e?mp.*[/\\]}}main{{[^ ]*}}.o{{"?}} -o {{.*[tT]e?mp.*[/\\]}}multi-threaded{{[^ ]*}}.o
 // EXEC: {{ld|clang}}
-// EXEC:  {{.*te?mp.*[/\\]}}main{{[^ ]*}}.o{{"?}} {{.*te?mp.*[/\\]}}multi-threaded{{[^ ]*}}.o
+// EXEC:  {{.*[tT]e?mp.*[/\\]}}main{{[^ ]*}}.o{{"?}} {{.*[tT]e?mp.*[/\\]}}multi-threaded{{[^ ]*}}.o
 
 // DEPENDENCIES-DAG: {{.*}}multi-threaded.o : {{.*[/\\]}}multi-threaded.swift {{.*[/\\]}}Inputs{{[/\\]}}main.swift
 // DEPENDENCIES-DAG: {{.*}}main.o : {{.*[/\\]}}multi-threaded.swift {{.*[/\\]}}Inputs{{[/\\]}}main.swift
diff --git a/test/IRGen/abitypes.swift b/test/IRGen/abitypes.swift
index 44e3db6869e..fd9b0eafabd 100644
--- a/test/IRGen/abitypes.swift
+++ b/test/IRGen/abitypes.swift
@@ -19,50 +19,50 @@ import Foundation
 
 class Foo {
   // x86_64-macosx: define hidden swiftcc { float, float, float, float } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(%T8abitypes3FooC* swiftself %0) {{.*}} {
-  // x86_64-macosx: define hidden { <2 x float>, <2 x float> } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1) unnamed_addr {{.*}} {
+  // x86_64-macosx: define hidden { <2 x float>, <2 x float> } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1) {{.*}} {
   // x86_64-ios: define hidden swiftcc { float, float, float, float } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(%T8abitypes3FooC* swiftself %0) {{.*}} {
-  // x86_64-ios: define hidden { <2 x float>, <2 x float> } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1) unnamed_addr {{.*}} {
+  // x86_64-ios: define hidden { <2 x float>, <2 x float> } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1) {{.*}} {
   // i386-ios: define hidden swiftcc void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(%TSo6MyRectV* noalias nocapture sret %0, %T8abitypes3FooC* swiftself %1) {{.*}} {
-  // i386-ios: define hidden void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(%TSo6MyRectV* noalias nocapture sret %0, i8* %1, i8* %2) unnamed_addr {{.*}} {
+  // i386-ios: define hidden void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(%TSo6MyRectV* noalias nocapture sret %0, i8* %1, i8* %2) {{.*}} {
   // armv7-ios: define hidden swiftcc { float, float, float, float } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(%T8abitypes3FooC* swiftself %0) {{.*}} {
-  // armv7-ios: define hidden void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(%TSo6MyRectV* noalias nocapture sret %0, i8* %1, i8* %2) unnamed_addr {{.*}} {
+  // armv7-ios: define hidden void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(%TSo6MyRectV* noalias nocapture sret %0, i8* %1, i8* %2) {{.*}} {
   // armv7s-ios: define hidden swiftcc { float, float, float, float } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(%T8abitypes3FooC* swiftself %0) {{.*}} {
-  // armv7s-ios: define hidden void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(%TSo6MyRectV* noalias nocapture sret %0, i8* %1, i8* %2) unnamed_addr {{.*}} {
+  // armv7s-ios: define hidden void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(%TSo6MyRectV* noalias nocapture sret %0, i8* %1, i8* %2) {{.*}} {
   // arm64-ios: define hidden swiftcc { float, float, float, float } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(%T8abitypes3FooC* swiftself %0) {{.*}} {
-  // arm64-ios: define hidden [[ARM64_MYRECT]] @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1) unnamed_addr {{.*}} {
+  // arm64-ios: define hidden [[ARM64_MYRECT]] @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1) {{.*}} {
   // x86_64-tvos: define hidden swiftcc { float, float, float, float } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(%T8abitypes3FooC* swiftself %0) {{.*}} {
-  // x86_64-tvos: define hidden { <2 x float>, <2 x float> } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %0) unnamed_addr {{.*}} {
+  // x86_64-tvos: define hidden { <2 x float>, <2 x float> } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %0) {{.*}} {
   // arm64-tvos: define hidden swiftcc { float, float, float, float }  @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(%T8abitypes3FooC* swiftself %0) {{.*}} {
-  // arm64-tvos: define hidden [[ARM64_MYRECT]] @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1) unnamed_addr {{.*}} {
+  // arm64-tvos: define hidden [[ARM64_MYRECT]] @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1) {{.*}} {
   // i386-watchos: define hidden swiftcc void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(%TSo6MyRectV* noalias nocapture sret %0, %T8abitypes3FooC* swiftself %1) {{.*}} {
-  // i386-watchos: define hidden void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(%TSo6MyRectV* noalias nocapture sret %0, i8* %1, i8* %2) unnamed_addr {{.*}} {
+  // i386-watchos: define hidden void @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(%TSo6MyRectV* noalias nocapture sret %0, i8* %1, i8* %2) {{.*}} {
   // armv7k-watchos: define hidden swiftcc { float, float, float, float } @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}F"(%T8abitypes3FooC* swiftself %0) {{.*}} {
-  // armv7k-watchos: define hidden [[ARMV7K_MYRECT]] @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1) unnamed_addr {{.*}} {
+  // armv7k-watchos: define hidden [[ARMV7K_MYRECT]] @"$s8abitypes3FooC3bar{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1) {{.*}} {
   @objc dynamic func bar() -> MyRect {
     return MyRect(x: 1, y: 2, width: 3, height: 4)
   }
 
 
   // x86_64-macosx: define hidden swiftcc double @"$s8abitypes3FooC14getXFromNSRect{{[_0-9a-zA-Z]*}}F"(double %0, double %1, double %2, double %3, %T8abitypes3FooC* swiftself %4) {{.*}} {
-  // x86_64-macosx: define hidden double @"$s8abitypes3FooC14getXFromNSRect{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, %TSo6CGRectV* byval align 8 %2) unnamed_addr {{.*}} {
+  // x86_64-macosx: define hidden double @"$s8abitypes3FooC14getXFromNSRect{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, %TSo6CGRectV* byval align 8 %2) {{.*}} {
   // armv7-ios: define hidden swiftcc double @"$s8abitypes3FooC14getXFromNSRect{{[_0-9a-zA-Z]*}}F"(float %0, float %1, float %2, float %3, %T8abitypes3FooC* swiftself %4) {{.*}} {
-  // armv7-ios: define hidden double @"$s8abitypes3FooC14getXFromNSRect{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, [4 x i32] %2) unnamed_addr {{.*}} {
+  // armv7-ios: define hidden double @"$s8abitypes3FooC14getXFromNSRect{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, [4 x i32] %2) {{.*}} {
   // armv7s-ios: define hidden swiftcc double @"$s8abitypes3FooC14getXFromNSRect{{[_0-9a-zA-Z]*}}F"(float %0, float %1, float %2, float %3, %T8abitypes3FooC* swiftself %3) {{.*}} {
-  // armv7s-ios: define hidden double @"$s8abitypes3FooC14getXFromNSRect{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, [4 x i32] %3) unnamed_addr {{.*}} {
+  // armv7s-ios: define hidden double @"$s8abitypes3FooC14getXFromNSRect{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, [4 x i32] %3) {{.*}} {
   // armv7k-watchos: define hidden swiftcc double @"$s8abitypes3FooC14getXFromNSRect{{[_0-9a-zA-Z]*}}F"(float %0, float %1, float %2, float %3, %T8abitypes3FooC* swiftself %4) {{.*}} {
-  // armv7k-watchos: define hidden double @"$s8abitypes3FooC14getXFromNSRect{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, [4 x float] %2) unnamed_addr {{.*}} {
+  // armv7k-watchos: define hidden double @"$s8abitypes3FooC14getXFromNSRect{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, [4 x float] %2) {{.*}} {
   @objc dynamic func getXFromNSRect(_ r: NSRect) -> Double {
     return Double(r.origin.x)
   }
 
   // x86_64-macosx: define hidden swiftcc float @"$s8abitypes3FooC12getXFromRect{{[_0-9a-zA-Z]*}}F"(float %0, float %1, float %2, float %3, %T8abitypes3FooC* swiftself %4) {{.*}} {
-  // x86_64-macosx: define hidden float @"$s8abitypes3FooC12getXFromRect{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, <2 x float> %2, <2 x float> %3) unnamed_addr {{.*}} {
+  // x86_64-macosx: define hidden float @"$s8abitypes3FooC12getXFromRect{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, <2 x float> %2, <2 x float> %3) {{.*}} {
   // armv7-ios: define hidden swiftcc float @"$s8abitypes3FooC12getXFromRect{{[_0-9a-zA-Z]*}}F"(float %0, float %1, float %2, float %3, %T8abitypes3FooC* swiftself %4) {{.*}} {
-  // armv7-ios: define hidden float @"$s8abitypes3FooC12getXFromRect{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, [4 x i32] %2) unnamed_addr {{.*}} {
+  // armv7-ios: define hidden float @"$s8abitypes3FooC12getXFromRect{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, [4 x i32] %2) {{.*}} {
   // armv7s-ios: define hidden swiftcc float @"$s8abitypes3FooC12getXFromRect{{[_0-9a-zA-Z]*}}F"(float %0, float %1, float %2, float %3, %T8abitypes3FooC* swiftself %4) {{.*}} {
-  // armv7s-ios: define hidden float @"$s8abitypes3FooC12getXFromRect{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, [4 x i32] %2) unnamed_addr {{.*}} {
+  // armv7s-ios: define hidden float @"$s8abitypes3FooC12getXFromRect{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, [4 x i32] %2) {{.*}} {
   // armv7k-watchos: define hidden swiftcc float @"$s8abitypes3FooC12getXFromRect{{[_0-9a-zA-Z]*}}F"(float %0, float %1, float %2, float %3, %T8abitypes3FooC* swiftself %4) {{.*}} {
-  // armv7k-watchos: define hidden float @"$s8abitypes3FooC12getXFromRect{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, [4 x float] %3) unnamed_addr {{.*}} {
+  // armv7k-watchos: define hidden float @"$s8abitypes3FooC12getXFromRect{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, [4 x float] %3) {{.*}} {
   @objc dynamic func getXFromRect(_ r: MyRect) -> Float {
     return r.x
   }
@@ -110,7 +110,7 @@ class Foo {
   }
 
   // Ensure that MyRect is passed as an indirect-byval on x86_64 because we run out of registers for direct arguments
-  // x86_64-macosx: define hidden float @"$s8abitypes3FooC25getXFromRectIndirectByVal{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, float %2, float %3, float %4, float %5, float %6, float %7, float %8, %TSo6MyRectV* byval align 8 %9) unnamed_addr {{.*}} {
+  // x86_64-macosx: define hidden float @"$s8abitypes3FooC25getXFromRectIndirectByVal{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, float %2, float %3, float %4, float %5, float %6, float %7, float %8, %TSo6MyRectV* byval align 8 %9) {{[#0-9]*}} {
   @objc dynamic func getXFromRectIndirectByVal(_: Float, second _: Float, 
                                        third _: Float, fourth _: Float,
                                        fifth _: Float, sixth _: Float,
@@ -173,7 +173,7 @@ class Foo {
   }
 
   // x86_64-macosx: define hidden swiftcc { double, double, double } @"$s8abitypes3FooC3baz{{[_0-9a-zA-Z]*}}F"(%T8abitypes3FooC* swiftself %0) {{.*}} {
-  // x86_64-macosx: define hidden void @"$s8abitypes3FooC3baz{{[_0-9a-zA-Z]*}}FTo"(%TSo4TrioV* noalias nocapture sret %0, i8* %1, i8* %2) unnamed_addr {{.*}} {
+  // x86_64-macosx: define hidden void @"$s8abitypes3FooC3baz{{[_0-9a-zA-Z]*}}FTo"(%TSo4TrioV* noalias nocapture sret %0, i8* %1, i8* %2) {{.*}} {
   @objc dynamic func baz() -> Trio {
     return Trio(i: 1.0, j: 2.0, k: 3.0)
   }
@@ -197,7 +197,7 @@ class Foo {
     return p.newPair()
   }
 
-  // x86_64-macosx:      define hidden i64 @"$s8abitypes3FooC8takepair{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, i64 %2) unnamed_addr {{.*}} {
+  // x86_64-macosx:      define hidden i64 @"$s8abitypes3FooC8takepair{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, i64 %2) {{.*}} {
   @objc dynamic func takepair(_ p: IntPair) -> IntPair {
     return p
   }
@@ -217,7 +217,7 @@ class Foo {
     return p.newNestedInts()
   }
 
-  // x86_64-macosx:      define hidden i8* @"$s8abitypes3FooC9copyClass{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, i8* %2) unnamed_addr {{.*}} {
+  // x86_64-macosx:      define hidden i8* @"$s8abitypes3FooC9copyClass{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, i8* %2) {{.*}} {
   // x86_64-macosx:      [[VALUE:%[0-9]+]] = call swiftcc [[TYPE:%.*]]* @"$s8abitypes3FooC9copyClass{{[_0-9a-zA-Z]*}}F"
   // x86_64-macosx:      [[T0:%.*]] = call [[OBJC:%objc_class]]* @swift_getObjCClassFromMetadata([[TYPE]]* [[VALUE]])
   // x86_64-macosx:      [[RESULT:%[0-9]+]] = bitcast [[OBJC]]* [[T0]] to i8*
@@ -226,7 +226,7 @@ class Foo {
     return a
   }
 
-  // x86_64-macosx:      define hidden i8* @"$s8abitypes3FooC9copyProto{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, i8* %2) unnamed_addr {{.*}} {
+  // x86_64-macosx:      define hidden i8* @"$s8abitypes3FooC9copyProto{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, i8* %2) {{.*}} {
   // x86_64-macosx:      [[VALUE:%[0-9]+]] = call swiftcc [[TYPE:%.*]] @"$s8abitypes3FooC9copyProto{{[_0-9a-zA-Z]*}}F"
   // x86_64-macosx:      [[RESULT:%[0-9]+]] = bitcast [[TYPE]] [[VALUE]] to i8*
   // x86_64-macosx:      ret i8* [[RESULT]]
@@ -234,7 +234,7 @@ class Foo {
     return a
   }
 
-  // x86_64-macosx:      define hidden i8* @"$s8abitypes3FooC13copyProtoComp{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, i8* %2) unnamed_addr {{.*}} {
+  // x86_64-macosx:      define hidden i8* @"$s8abitypes3FooC13copyProtoComp{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, i8* %2) {{.*}} {
   // x86_64-macosx:      [[VALUE:%[0-9]+]] = call swiftcc [[TYPE:%.*]] @"$s8abitypes3FooC13copyProtoComp{{[_0-9a-zA-Z]*}}F"
   // x86_64-macosx:      [[RESULT:%[0-9]+]] = bitcast [[TYPE]] [[VALUE]] to i8*
   // x86_64-macosx:      ret i8* [[RESULT]]
@@ -243,7 +243,7 @@ class Foo {
   }
 
   // x86_64-macosx:       define hidden swiftcc i1 @"$s8abitypes3FooC6negate{{[_0-9a-zA-Z]*}}F"(i1 %0, %T8abitypes3FooC* swiftself %1) {{.*}} {
-  // x86_64-macosx:       define hidden signext i8 @"$s8abitypes3FooC6negate{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, i8 signext %2) unnamed_addr {{.*}} {
+  // x86_64-macosx:       define hidden signext i8 @"$s8abitypes3FooC6negate{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, i8 signext %2) {{.*}} {
   // x86_64-macosx:       [[R1:%[0-9]+]] = call swiftcc i1 @"$s10ObjectiveC22_convertObjCBoolToBool{{[_0-9a-zA-Z]*}}F"
   // x86_64-macosx:       [[R2:%[0-9]+]] = call swiftcc i1 @"$s8abitypes3FooC6negate{{[_0-9a-zA-Z]*}}F"
   // x86_64-macosx:       [[R3:%[0-9]+]] = call swiftcc i8 @"$s10ObjectiveC22_convertBoolToObjCBool{{[_0-9a-zA-Z]*}}F"(i1 [[R2]]
@@ -257,14 +257,14 @@ class Foo {
   // x86_64-ios-fixme:          ret i1 [[R3]]
   //
   // armv7-ios-fixme:     define hidden i1 @"$s8abitypes3FooC6negate{{[_0-9a-zA-Z]*}}F"(i1 %0, %T8abitypes3FooC* %1) {{.*}} {
-  // armv7-ios-fixme:     define internal signext i8 @"$s8abitypes3FooC6negate{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, i8 signext %2) unnamed_addr {{.*}} {
+  // armv7-ios-fixme:     define internal signext i8 @"$s8abitypes3FooC6negate{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, i8 signext %2) {{.*}} {
   // armv7-ios-fixme:     [[R1:%[0-9]+]] = call i1 @"$s10ObjectiveC22_convertObjCBoolToBool1xSbAA0cD0V_tF"
   // armv7-ios-fixme:     [[R2:%[0-9]+]] = call i1 @"$s8abitypes3FooC6negate{{[_0-9a-zA-Z]*}}F"(i1 [[R1]]
   // armv7-ios-fixme:     [[R3:%[0-9]+]] = call i8 @"$s10ObjectiveC22_convertBoolToObjCBoolAA0eF0VSb1x_tF"(i1 [[R2]]
   // armv7-ios-fixme:     ret i8 [[R3]]
   //
   // armv7s-ios-fixme:     define hidden i1 @"$s8abitypes3FooC6negate{{[_0-9a-zA-Z]*}}F"(i1, %T8abitypes3FooC*) {{.*}} {
-  // armv7s-ios-fixme:     define internal signext i8 @"$s8abitypes3FooC6negate{{[_0-9a-zA-Z]*}}FTo"(i8*, i8*, i8 signext) unnamed_addr {{.*}} {
+  // armv7s-ios-fixme:     define internal signext i8 @"$s8abitypes3FooC6negate{{[_0-9a-zA-Z]*}}FTo"(i8*, i8*, i8 signext) {{[#0-9]*}} {
   // armv7s-ios-fixme:     [[R1:%[0-9]+]] = call i1 @"$s10ObjectiveC22_convertObjCBoolToBool1xSbAA0cD0V_tF"
   // armv7s-ios-fixme:     [[R2:%[0-9]+]] = call i1 @"$s8abitypes3FooC6negate{{[_0-9a-zA-Z]*}}F"(i1 [[R1]]
   // armv7s-ios-fixme:     [[R3:%[0-9]+]] = call i8 @"$s10ObjectiveC22_convertBoolToObjCBoolAA0eF0VSb1x_tF"(i1 [[R2]]
@@ -276,7 +276,7 @@ class Foo {
   // arm64-ios-fixme:     ret i1 [[R2]]
   //
   // i386-ios-fixme:      define hidden i1 @"$s8abitypes3FooC6negate{{[_0-9a-zA-Z]*}}F"(i1, %T8abitypes3FooC*) {{.*}} {
-  // i386-ios-fixme:      define internal signext i8 @"$s8abitypes3FooC6negate{{[_0-9a-zA-Z]*}}FTo"(i8*, i8*, i8 signext) unnamed_addr {{.*}} {
+  // i386-ios-fixme:      define internal signext i8 @"$s8abitypes3FooC6negate{{[_0-9a-zA-Z]*}}FTo"(i8*, i8*, i8 signext) {{[#0-9]*}} {
   // i386-ios-fixme:     [[R1:%[0-9]+]] = call i1 @"$s10ObjectiveC22_convertObjCBoolToBool{{[_0-9a-zA-Z]*}}F"
   // i386-ios-fixme:     [[R2:%[0-9]+]] = call i1 @"$s8abitypes3FooC6negate{{[_0-9a-zA-Z]*}}F"(i1 [[R1]]
   // i386-ios-fixme:     [[R3:%[0-9]+]] = call i8 @"$s10ObjectiveC22_convertBoolToObjCBool{{[_0-9a-zA-Z]*}}F"(i1 [[R2]]
@@ -464,17 +464,17 @@ class Foo {
     try g.negateThrowing(b)
   }
 
-  // x86_64-macosx: define hidden i32* @"$s8abitypes3FooC24copyUnsafeMutablePointer{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, i32* %2) unnamed_addr {{.*}} {
+  // x86_64-macosx: define hidden i32* @"$s8abitypes3FooC24copyUnsafeMutablePointer{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, i32* %2) {{.*}} {
   @objc dynamic func copyUnsafeMutablePointer(_ p: UnsafeMutablePointer<Int32>) -> UnsafeMutablePointer<Int32> {
     return p
   }
 
-  // x86_64-macosx: define hidden i64 @"$s8abitypes3FooC17returnNSEnumValue{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1) unnamed_addr {{.*}} {
+  // x86_64-macosx: define hidden i64 @"$s8abitypes3FooC17returnNSEnumValue{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1) {{.*}} {
   @objc dynamic func returnNSEnumValue() -> ByteCountFormatter.CountStyle {
     return .file
   }
 
-  // x86_64-macosx: define hidden zeroext i16 @"$s8abitypes3FooC20returnOtherEnumValue{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, i16 zeroext %2) unnamed_addr {{.*}} {
+  // x86_64-macosx: define hidden zeroext i16 @"$s8abitypes3FooC20returnOtherEnumValue{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, i16 zeroext %2) {{.*}} {
   @objc dynamic func returnOtherEnumValue(_ choice: ChooseTo) -> ChooseTo {
     switch choice {
       case .takeIt: return .leaveIt
@@ -483,7 +483,7 @@ class Foo {
   }
 
   // x86_64-macosx: define hidden swiftcc i32 @"$s8abitypes3FooC10getRawEnum{{[_0-9a-zA-Z]*}}F"(%T8abitypes3FooC* swiftself %0) {{.*}} {
-  // x86_64-macosx: define hidden i32 @"$s8abitypes3FooC10getRawEnum{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1) unnamed_addr {{.*}} {
+  // x86_64-macosx: define hidden i32 @"$s8abitypes3FooC10getRawEnum{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1) {{.*}} {
   @objc dynamic func getRawEnum() -> RawEnum {
     return Intergalactic
   }
@@ -493,7 +493,7 @@ class Foo {
     self.work = work
   }
 
-  // x86_64-macosx: define hidden void @"$s8abitypes3FooC13testArchetype{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, i8* %2) unnamed_addr {{.*}} {
+  // x86_64-macosx: define hidden void @"$s8abitypes3FooC13testArchetype{{[_0-9a-zA-Z]*}}FTo"(i8* %0, i8* %1, i8* %2) {{.*}} {
   @objc dynamic func testArchetype(_ work: Work) {
     work.doStuff(1)
     // x86_64-macosx: [[OBJCPTR:%.*]] = bitcast i8* %2 to %objc_object*
@@ -514,10 +514,10 @@ class Foo {
   }
 
   // arm64-ios: define hidden swiftcc { i64, i64, i64, i64 } @"$s8abitypes3FooC14callJustReturn{{[_0-9a-zA-Z]*}}F"(%TSo13StructReturnsC* %0, i64 %1, i64 %2, i64 %3, i64 %4, %T8abitypes3FooC* swiftself %5) {{.*}} {
-  // arm64-ios: define hidden void @"$s8abitypes3FooC14callJustReturn{{[_0-9a-zA-Z]*}}FTo"(%TSo9BigStructV* noalias nocapture sret, i8*, i8*, [[OPAQUE:.*]]*, %TSo9BigStructV*) unnamed_addr {{.*}} {
+  // arm64-ios: define hidden void @"$s8abitypes3FooC14callJustReturn{{[_0-9a-zA-Z]*}}FTo"(%TSo9BigStructV* noalias nocapture sret, i8*, i8*, [[OPAQUE:.*]]*, %TSo9BigStructV*) {{.*}} {
   //
   // arm64-tvos: define hidden swiftcc { i64, i64, i64, i64 } @"$s8abitypes3FooC14callJustReturn{{[_0-9a-zA-Z]*}}F"(%TSo13StructReturnsC* %0, i64 %1, i64 %2, i64 %3, i64 %4, %T8abitypes3FooC* swiftself %5) {{.*}} {
-  // arm64-tvos: define hidden void @"$s8abitypes3FooC14callJustReturn{{[_0-9a-zA-Z]*}}FTo"(%TSo9BigStructV* noalias nocapture sret, i8*, i8*, [[OPAQUE:.*]]*, %TSo9BigStructV*) unnamed_addr {{.*}} {
+  // arm64-tvos: define hidden void @"$s8abitypes3FooC14callJustReturn{{[_0-9a-zA-Z]*}}FTo"(%TSo9BigStructV* noalias nocapture sret, i8*, i8*, [[OPAQUE:.*]]*, %TSo9BigStructV*) {{.*}} {
   @objc dynamic func callJustReturn(_ r: StructReturns, with v: BigStruct) -> BigStruct {
     return r.justReturn(v)
   }
diff --git a/test/IRGen/access_type_metadata_by_mangled_name_objc.swift b/test/IRGen/access_type_metadata_by_mangled_name_objc.swift
index 3322426d97d..68b1d646733 100644
--- a/test/IRGen/access_type_metadata_by_mangled_name_objc.swift
+++ b/test/IRGen/access_type_metadata_by_mangled_name_objc.swift
@@ -12,7 +12,8 @@ public func test() {
   var x: Any.Type
 
   // Access ObjC classes by mangled name.
-  // CHECK: @"$sSo8NSObjectCMD"
+  // FIXME: Disabled for now.
+  // CHECK: @"$sSo8NSObjectCMa"
   x = NSObject.self
 
   // Use the metadata accessor for CF classes that already has to exist.
diff --git a/test/IRGen/method_linkage.swift b/test/IRGen/method_linkage.swift
index 1598200d4fe..886191eac93 100644
--- a/test/IRGen/method_linkage.swift
+++ b/test/IRGen/method_linkage.swift
@@ -118,6 +118,10 @@ open class OpenSubclass : OpenClass {
   fileprivate final override var prop: () {
     return ()
   }
+
+  // CHECK: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s14method_linkage12OpenSubclassC4pbazyyF"
+  // RESILIENT: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s14method_linkage12OpenSubclassC4pbazyyF"
+  public final override func pbaz() {}
 }
 
 // Just in case anyone wants to delete unused methods...
diff --git a/test/IRGen/objc_bridge.swift b/test/IRGen/objc_bridge.swift
index 340f4a577c7..20147403ce4 100644
--- a/test/IRGen/objc_bridge.swift
+++ b/test/IRGen/objc_bridge.swift
@@ -130,8 +130,8 @@ var NSS : NSString = NSString()
 
 // -- NSString methods don't convert 'self'
 extension NSString {
-  // CHECK: define internal [[OPAQUE:.*]]* @"$sSo8NSStringC11objc_bridgeE13nsstrFakePropABvgTo"([[OPAQUE:.*]]* %0, i8* %1) unnamed_addr
-  // CHECK: define internal void @"$sSo8NSStringC11objc_bridgeE13nsstrFakePropABvsTo"([[OPAQUE:.*]]* %0, i8* %1, [[OPAQUE:.*]]* %2) unnamed_addr
+  // CHECK: define internal [[OPAQUE:.*]]* @"$sSo8NSStringC11objc_bridgeE13nsstrFakePropABvgTo"([[OPAQUE:.*]]* %0, i8* %1)
+  // CHECK: define internal void @"$sSo8NSStringC11objc_bridgeE13nsstrFakePropABvsTo"([[OPAQUE:.*]]* %0, i8* %1, [[OPAQUE:.*]]* %2)
   @objc var nsstrFakeProp : NSString {
     get {
       return NSS
@@ -139,20 +139,20 @@ extension NSString {
     set {}
   }
 
-  // CHECK: define internal [[OPAQUE:.*]]* @"$sSo8NSStringC11objc_bridgeE11nsstrResultAByFTo"([[OPAQUE:.*]]* %0, i8* %1) unnamed_addr
+  // CHECK: define internal [[OPAQUE:.*]]* @"$sSo8NSStringC11objc_bridgeE11nsstrResultAByFTo"([[OPAQUE:.*]]* %0, i8* %1)
   @objc func nsstrResult() -> NSString { return NSS }
 
-  // CHECK: define internal void @"$sSo8NSStringC11objc_bridgeE8nsstrArg1syAB_tFTo"([[OPAQUE:.*]]* %0, i8* %1, [[OPAQUE:.*]]* %2) unnamed_addr
+  // CHECK: define internal void @"$sSo8NSStringC11objc_bridgeE8nsstrArg1syAB_tFTo"([[OPAQUE:.*]]* %0, i8* %1, [[OPAQUE:.*]]* %2)
   @objc func nsstrArg(s s: NSString) { }
 }
 
 class Bas : NSObject {
-  // CHECK: define internal [[OPAQUE:.*]]* @"$s11objc_bridge3BasC11strRealPropSSvgTo"([[OPAQUE:.*]]* %0, i8* %1) unnamed_addr {{.*}} {
-  // CHECK: define internal void @"$s11objc_bridge3BasC11strRealPropSSvsTo"([[OPAQUE:.*]]* %0, i8* %1, [[OPAQUE:.*]]* %2) unnamed_addr {{.*}} {
+  // CHECK: define internal [[OPAQUE:.*]]* @"$s11objc_bridge3BasC11strRealPropSSvgTo"([[OPAQUE:.*]]* %0, i8* %1) {{.*}} {
+  // CHECK: define internal void @"$s11objc_bridge3BasC11strRealPropSSvsTo"([[OPAQUE:.*]]* %0, i8* %1, [[OPAQUE:.*]]* %2) {{.*}} {
   @objc var strRealProp : String
 
-  // CHECK: define internal [[OPAQUE:.*]]* @"$s11objc_bridge3BasC11strFakePropSSvgTo"([[OPAQUE:.*]]* %0, i8* %1) unnamed_addr {{.*}} {
-  // CHECK: define internal void @"$s11objc_bridge3BasC11strFakePropSSvsTo"([[OPAQUE:.*]]* %0, i8* %1, [[OPAQUE:.*]]* %2) unnamed_addr {{.*}} {
+  // CHECK: define internal [[OPAQUE:.*]]* @"$s11objc_bridge3BasC11strFakePropSSvgTo"([[OPAQUE:.*]]* %0, i8* %1) {{.*}} {
+  // CHECK: define internal void @"$s11objc_bridge3BasC11strFakePropSSvsTo"([[OPAQUE:.*]]* %0, i8* %1, [[OPAQUE:.*]]* %2) {{.*}} {
   @objc var strFakeProp : String {
     get {
       return ""
@@ -160,12 +160,12 @@ class Bas : NSObject {
     set {}
   }
 
-  // CHECK: define internal [[OPAQUE:.*]]* @"$s11objc_bridge3BasC13nsstrRealPropSo8NSStringCvgTo"([[OPAQUE:.*]]* %0, i8* %1) unnamed_addr {{.*}} {
-  // CHECK: define internal void @"$s11objc_bridge3BasC13nsstrRealPropSo8NSStringCvsTo"([[OPAQUE:.*]]* %0, i8* %1, [[OPAQUE:.*]]* %2) unnamed_addr {{.*}} {
+  // CHECK: define internal [[OPAQUE:.*]]* @"$s11objc_bridge3BasC13nsstrRealPropSo8NSStringCvgTo"([[OPAQUE:.*]]* %0, i8* %1) {{.*}} {
+  // CHECK: define internal void @"$s11objc_bridge3BasC13nsstrRealPropSo8NSStringCvsTo"([[OPAQUE:.*]]* %0, i8* %1, [[OPAQUE:.*]]* %2) {{.*}} {
   @objc var nsstrRealProp : NSString
 
   // CHECK: define hidden swiftcc %TSo8NSStringC* @"$s11objc_bridge3BasC13nsstrFakePropSo8NSStringCvg"(%T11objc_bridge3BasC* swiftself %0) {{.*}} {
-  // CHECK: define internal void @"$s11objc_bridge3BasC13nsstrFakePropSo8NSStringCvsTo"([[OPAQUE:.*]]* %0, i8* %1, [[OPAQUE:.*]]* %2) unnamed_addr {{.*}} {
+  // CHECK: define internal void @"$s11objc_bridge3BasC13nsstrFakePropSo8NSStringCvsTo"([[OPAQUE:.*]]* %0, i8* %1, [[OPAQUE:.*]]* %2) {{.*}} {
   @objc var nsstrFakeProp : NSString {
     get {
       return NSS
@@ -173,14 +173,14 @@ class Bas : NSObject {
     set {}
   }
 
-  // CHECK: define internal [[OPAQUE:.*]]* @"$s11objc_bridge3BasC9strResultSSyFTo"([[OPAQUE:.*]]* %0, i8* %1) unnamed_addr {{.*}} {
+  // CHECK: define internal [[OPAQUE:.*]]* @"$s11objc_bridge3BasC9strResultSSyFTo"([[OPAQUE:.*]]* %0, i8* %1) {{.*}} {
   @objc func strResult() -> String { return "" }
-  // CHECK: define internal void @"$s11objc_bridge3BasC6strArg1sySS_tFTo"([[OPAQUE:.*]]* %0, i8* %1, [[OPAQUE:.*]]* %2) unnamed_addr {{.*}} {
+  // CHECK: define internal void @"$s11objc_bridge3BasC6strArg1sySS_tFTo"([[OPAQUE:.*]]* %0, i8* %1, [[OPAQUE:.*]]* %2) {{.*}} {
   @objc func strArg(s s: String) { }
 
-  // CHECK: define internal [[OPAQUE:.*]]* @"$s11objc_bridge3BasC11nsstrResultSo8NSStringCyFTo"([[OPAQUE:.*]]* %0, i8* %1) unnamed_addr {{.*}} {
+  // CHECK: define internal [[OPAQUE:.*]]* @"$s11objc_bridge3BasC11nsstrResultSo8NSStringCyFTo"([[OPAQUE:.*]]* %0, i8* %1) {{.*}} {
   @objc func nsstrResult() -> NSString { return NSS }
-  // CHECK: define internal void @"$s11objc_bridge3BasC8nsstrArg1sySo8NSStringC_tFTo"([[OPAQUE:.*]]* %0, i8* %1, [[OPAQUE:.*]]* %2) unnamed_addr {{.*}} {
+  // CHECK: define internal void @"$s11objc_bridge3BasC8nsstrArg1sySo8NSStringC_tFTo"([[OPAQUE:.*]]* %0, i8* %1, [[OPAQUE:.*]]* %2) {{.*}} {
   @objc func nsstrArg(s s: NSString) { }
 
   override init() { 
diff --git a/test/IRGen/objc_class_export.swift b/test/IRGen/objc_class_export.swift
index d627da20b8d..f181fb6f442 100644
--- a/test/IRGen/objc_class_export.swift
+++ b/test/IRGen/objc_class_export.swift
@@ -81,7 +81,7 @@ struct BigStructWithNativeObjects {
 
   @objc func drawInRect(dirty dirty: NSRect) {
   }
-  // CHECK: define internal void @"$s17objc_class_export3FooC10drawInRect5dirtyySo6NSRectV_tFTo"([[OPAQUE:%.*]]* %0, i8* %1, [[NSRECT]]* byval align 8 %2) unnamed_addr {{.*}} {
+  // CHECK: define internal void @"$s17objc_class_export3FooC10drawInRect5dirtyySo6NSRectV_tFTo"([[OPAQUE:%.*]]* %0, i8* %1, [[NSRECT]]* byval align 8 %2) {{[#0-9]*}} {
   // CHECK:   [[CAST:%[a-zA-Z0-9]+]] = bitcast [[OPAQUE]]* %0 to [[FOO]]*
   // CHECK:   call swiftcc void @"$s17objc_class_export3FooC10drawInRect5dirtyySo6NSRectV_tF"(double {{.*}}, double {{.*}}, double {{.*}}, double {{.*}}, [[FOO]]* swiftself [[CAST]])
   // CHECK: }
@@ -90,14 +90,14 @@ struct BigStructWithNativeObjects {
     return NSRect(origin: NSPoint(x: 0, y: 0), 
                   size: NSSize(width: 0, height: 0))
   }
-  // CHECK: define internal void @"$s17objc_class_export3FooC6boundsSo6NSRectVyFTo"([[NSRECT]]* noalias nocapture sret %0, [[OPAQUE4:%.*]]* %1, i8* %2) unnamed_addr {{.*}} {
+  // CHECK: define internal void @"$s17objc_class_export3FooC6boundsSo6NSRectVyFTo"([[NSRECT]]* noalias nocapture sret %0, [[OPAQUE4:%.*]]* %1, i8* %2) {{.*}} {
   // CHECK:   [[CAST:%[a-zA-Z0-9]+]] = bitcast [[OPAQUE4]]* %1 to [[FOO]]*
   // CHECK:   call swiftcc { double, double, double, double } @"$s17objc_class_export3FooC6boundsSo6NSRectVyF"([[FOO]]* swiftself [[CAST]])
 
   @objc func convertRectToBacking(r r: NSRect) -> NSRect {
     return r
   }
-  // CHECK: define internal void @"$s17objc_class_export3FooC20convertRectToBacking1rSo6NSRectVAG_tFTo"([[NSRECT]]* noalias nocapture sret %0, [[OPAQUE5:%.*]]* %1, i8* %2, [[NSRECT]]* byval align 8 %3) unnamed_addr {{.*}} {
+  // CHECK: define internal void @"$s17objc_class_export3FooC20convertRectToBacking1rSo6NSRectVAG_tFTo"([[NSRECT]]* noalias nocapture sret %0, [[OPAQUE5:%.*]]* %1, i8* %2, [[NSRECT]]* byval align 8 %3) {{.*}} {
   // CHECK:   [[CAST:%[a-zA-Z0-9]+]] = bitcast [[OPAQUE5]]* %1 to [[FOO]]*
   // CHECK:   call swiftcc { double, double, double, double } @"$s17objc_class_export3FooC20convertRectToBacking1rSo6NSRectVAG_tF"(double {{.*}}, double {{.*}}, double {{.*}}, double {{.*}}, [[FOO]]* swiftself [[CAST]])
 
diff --git a/test/IRGen/objc_dealloc.sil b/test/IRGen/objc_dealloc.sil
index ef6609225a7..15a33f7f184 100644
--- a/test/IRGen/objc_dealloc.sil
+++ b/test/IRGen/objc_dealloc.sil
@@ -70,7 +70,7 @@ bb0(%0 : @unowned $X, %1 : @unowned $SwiftGizmo):
   return %7 : $()                                 // id: %8
 }
 
-// CHECK: define internal void @"$s12objc_dealloc10SwiftGizmoCfDTo"([[OPAQUE:%.*]]* %0, i8* %1) unnamed_addr
+// CHECK: define internal void @"$s12objc_dealloc10SwiftGizmoCfDTo"([[OPAQUE:%.*]]* %0, i8* %1) {{[#0-9]*}} {
 sil [ossa] @$s12objc_dealloc10SwiftGizmoCfDTo : $@convention(objc_method) (SwiftGizmo) -> () {
 bb0(%0 : @unowned $SwiftGizmo):
   // CHECK-NEXT: entry
diff --git a/test/IRGen/objc_function_merge.swift b/test/IRGen/objc_function_merge.swift
new file mode 100644
index 00000000000..c2e07effb02
--- /dev/null
+++ b/test/IRGen/objc_function_merge.swift
@@ -0,0 +1,56 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift -O %s -module-name=test -o %t/a.out
+// RUN: %target-build-swift -O %s -module-name=test -emit-ir | %FileCheck --check-prefix=CHECK-IR %s
+// RUN: %target-codesign %t/a.out
+// RUN: %target-run %t/a.out | %FileCheck %s
+// REQUIRES: executable_test
+// REQUIRES: objc_interop
+
+// In some places Foundation is comparing ObjC method pointers.
+// Therefore LLVM's function merging pass must not create aliases for identical
+// functions, but create thunks. This can be ensured if ObjC methods are not
+// created with the unnamed_addr attribute.
+
+import Foundation
+
+class Base: NSObject, NSSecureCoding {
+  @objc public class var supportsSecureCoding: Bool {
+    return true
+  }
+  
+  @objc let s: String
+  
+  func encode(with coder: NSCoder) {
+    coder.encode(s, forKey:  #keyPath(s))
+  }
+  
+  init(s: String) {
+    self.s = s
+  }
+  
+  required init?(coder: NSCoder) {
+    self.s = coder.value(forKey: #keyPath(s)) as! String
+  }
+}
+
+class Derived : Base {
+  // Make sure the overridden method is not merged with the base method (without
+  // creating a thunk), so that the method pointers remain distinct.
+  @objc public class override var supportsSecureCoding: Bool {
+    return true
+  }
+}
+
+
+// Check if the objc methods are not generated with the unnamed_addr attribute.
+// CHECK-IR-DAG: define {{.*}} @"$s4test4BaseC20supportsSecureCodingSbvgZTo"({{[^\)]*}}) #{{[0-9]+}} {
+// CHECK-IR-DAG: define {{.*}} @"$s4test4BaseC6encode4withySo7NSCoderC_tFTo"({{[^\)]*}}) #{{[0-9]+}} {
+// CHECK-IR-DAG: define {{.*}} @"$s4test7DerivedC20supportsSecureCodingSbvgZTo"({{[^\)]*}}) #{{[0-9]+}} {
+
+let d = Derived(s: "")
+if #available(macOS 10.13, iOS 11, tvOS 11, watchOS 4, *) {
+  // Check that we don't crash here.
+  _ = try NSKeyedArchiver.archivedData(withRootObject: d, requiringSecureCoding: true)
+}
+// CHECK: okay
+print("okay")
diff --git a/test/IRGen/objc_subscripts.swift b/test/IRGen/objc_subscripts.swift
index 498d7941a02..2399743a743 100644
--- a/test/IRGen/objc_subscripts.swift
+++ b/test/IRGen/objc_subscripts.swift
@@ -42,7 +42,7 @@
 
 @objc class SomeObject {
   @objc subscript (i : Int) -> SomeObject {
-    // CHECK: define internal [[OPAQUE0:%.*]]* @"$s15objc_subscripts10SomeObjectCyACSicigTo"([[OPAQUE1]]* %0, i8* %1, i64 %2) unnamed_addr
+    // CHECK: define internal [[OPAQUE0:%.*]]* @"$s15objc_subscripts10SomeObjectCyACSicigTo"([[OPAQUE1]]* %0, i8* %1, i64 %2) {{[#0-9]*}} {
     get {
       // CHECK: call swiftcc %T15objc_subscripts10SomeObjectC* @"$s15objc_subscripts10SomeObjectCyACSicig"
       return self
diff --git a/test/IRGen/objc_types_as_member.sil b/test/IRGen/objc_types_as_member.sil
index b996fe96c2e..381b3528e41 100644
--- a/test/IRGen/objc_types_as_member.sil
+++ b/test/IRGen/objc_types_as_member.sil
@@ -9,8 +9,10 @@ import gizmo
 sil @use_metatype : $@convention(thin) <T> (@thin T.Type) -> ()
 
 // CHECK-LABEL: define swiftcc void @test(%TSo014OuterTypeInnerB0C* swiftself %0, %swift.type* %Self, i8** %SelfWitnessTable)
-// CHECK:   [[TMP:%.*]] = call {{.*}}@"$sSo9OuterTypeCMD"
-// CHECK:   call swiftcc void @use_metatype(%swift.type* [[TMP]])
+// FIXME:   Metadata realization via demangling is disabled for now
+// CHECK:   [[TMP:%.*]] = call swiftcc %swift.metadata_response @"$sSo9OuterTypeCMa"
+// CHECK:   [[METADATA:%.*]] = extractvalue %swift.metadata_response %1, 0
+// CHECK:   call swiftcc void @use_metatype(%swift.type* [[METADATA]])
 // CHECK:   ret void
 
 sil @test : $@convention(witness_method: NSRuncing) (@guaranteed OuterType.InnerType) -> () {
diff --git a/test/IRGen/prespecialized-metadata/struct-inmodule-1argument-clang_node-1distinct_use.swift b/test/IRGen/prespecialized-metadata/struct-inmodule-1argument-clang_node-1distinct_use.swift
index 447889caac1..d8003b4b7e3 100644
--- a/test/IRGen/prespecialized-metadata/struct-inmodule-1argument-clang_node-1distinct_use.swift
+++ b/test/IRGen/prespecialized-metadata/struct-inmodule-1argument-clang_node-1distinct_use.swift
@@ -26,7 +26,7 @@ struct Value<T> {
 
 // CHECK: define hidden swiftcc void @"$s4main4doityyF"() #{{[0-9]+}} {
 // CHECK:   [[TYPE:%[0-9]+]] = call %swift.type* @__swift_instantiateConcreteTypeFromMangledName({ i32, i32 }* @"$s4main5ValueVySo12NSDictionaryCGMD") #{{[0-9]+}}
-// CHECK:   call swiftcc void @"$s4main7consumeyyxlF"(%swift.opaque* noalias nocapture %12, %swift.type* [[TYPE]])
+// CHECK:   call swiftcc void @"$s4main7consumeyyxlF"(%swift.opaque* noalias nocapture {{%.*}}, %swift.type* [[TYPE]])
 // CHECK: }
 func doit() {
   consume(Value(NSDictionary()))
diff --git a/test/ModuleInterface/ModuleCache/prebuilt-module-cache-forwarding.swift b/test/ModuleInterface/ModuleCache/prebuilt-module-cache-forwarding.swift
index a882d8843b6..67be554ade6 100644
--- a/test/ModuleInterface/ModuleCache/prebuilt-module-cache-forwarding.swift
+++ b/test/ModuleInterface/ModuleCache/prebuilt-module-cache-forwarding.swift
@@ -50,3 +50,5 @@ struct X {}
 let _: X = Lib.testValue
 // FROM-INTERFACE: [[@LINE-1]]:16: error: cannot convert value of type 'FromInterface' to specified type 'X'
 // FROM-PREBUILT: [[@LINE-2]]:16: error: cannot convert value of type 'FromPrebuilt' to specified type 'X'
+
+// REQUIRES: rdar58578342
diff --git a/test/ModuleInterface/swift_build_sdk_interfaces/early-exits.test-sh b/test/ModuleInterface/swift_build_sdk_interfaces/early-exits.test-sh
index bf9f8ced03b..d6e53a0135c 100644
--- a/test/ModuleInterface/swift_build_sdk_interfaces/early-exits.test-sh
+++ b/test/ModuleInterface/swift_build_sdk_interfaces/early-exits.test-sh
@@ -1,8 +1,8 @@
-RUN: not %swift_build_sdk_interfaces 2>&1 | %FileCheck -check-prefix NO-OUTPUT %s
+RUN: env SWIFT_EXEC=%swiftc_driver_plain not %{python} %utils/swift_build_sdk_interfaces.py %mcp_opt 2>&1 | %FileCheck -check-prefix NO-OUTPUT %s
 NO-OUTPUT: argument -o is required
 
-RUN: not env -u SDKROOT %swift_build_sdk_interfaces -o %t 2>&1 | %FileCheck -check-prefix NO-SDK %s
+RUN: env -u SDKROOT SWIFT_EXEC=%swiftc_driver_plain not %{python} %utils/swift_build_sdk_interfaces.py %mcp_opt -o %t 2>&1 | %FileCheck -check-prefix NO-SDK %s
 NO-SDK: SDKROOT must be set
 
-RUN: not %swift_build_sdk_interfaces -o %t -sdk %S/nonexistent 2>&1 | %FileCheck -check-prefix BAD-SDK %s
+RUN: env SWIFT_EXEC=%swiftc_driver_plain not %{python} %utils/swift_build_sdk_interfaces.py %mcp_opt -o %t -sdk %S/nonexistent 2>&1 | %FileCheck -check-prefix BAD-SDK %s
 BAD-SDK: invalid SDK: {{.+[/\\]nonexistent$}}
diff --git a/test/ModuleInterface/swift_build_sdk_interfaces/ignore-non-stdlib-failures.test-sh b/test/ModuleInterface/swift_build_sdk_interfaces/ignore-non-stdlib-failures.test-sh
index 2e2c6e925f5..5747b3cfe0d 100644
--- a/test/ModuleInterface/swift_build_sdk_interfaces/ignore-non-stdlib-failures.test-sh
+++ b/test/ModuleInterface/swift_build_sdk_interfaces/ignore-non-stdlib-failures.test-sh
@@ -1,4 +1,4 @@
-RUN: not %swift_build_sdk_interfaces -sdk %S/Inputs/xfails-sdk/ -v -o %t/output | %FileCheck %s
+RUN: env SWIFT_EXEC=%swiftc_driver_plain not %{python} %utils/swift_build_sdk_interfaces.py %mcp_opt -sdk %S/Inputs/xfails-sdk/ -v -o %t/output | %FileCheck %s
 
 CHECK-DAG: # (FAIL) {{.+}}{{\\|/}}Bad.swiftinterface
 CHECK-DAG: # (PASS) {{.+}}{{\\|/}}Good.swiftinterface
@@ -8,11 +8,11 @@ RUN: %swift_build_sdk_interfaces -sdk %S/Inputs/xfails-sdk/ -v -o %t/output -ign
 CHECK-IGNORING-FAILURES-DAG: # (XFAIL) {{.+}}{{\\|/}}Bad.swiftinterface
 CHECK-IGNORING-FAILURES-DAG: # (UPASS) {{.+}}{{\\|/}}Good.swiftinterface
 
-RUN: not %swift_build_sdk_interfaces -sdk %S/Inputs/broken-stdlib-sdk/ -v -o %t/output | %FileCheck -check-prefix CHECK-BROKEN-STDLIB %s
-RUN: not %swift_build_sdk_interfaces -sdk %S/Inputs/broken-stdlib-sdk/ -v -o %t/output -ignore-non-stdlib-failures | %FileCheck -check-prefix CHECK-BROKEN-STDLIB %s
+RUN: env SWIFT_EXEC=%swiftc_driver_plain not %{python} %utils/swift_build_sdk_interfaces.py %mcp_opt -sdk %S/Inputs/broken-stdlib-sdk/ -v -o %t/output | %FileCheck -check-prefix CHECK-BROKEN-STDLIB %s
+RUN: env SWIFT_EXEC=%swiftc_driver_plain not %{python} %utils/swift_build_sdk_interfaces.py %mcp_opt -sdk %S/Inputs/broken-stdlib-sdk/ -v -o %t/output -ignore-non-stdlib-failures | %FileCheck -check-prefix CHECK-BROKEN-STDLIB %s
 
 CHECK-BROKEN-STDLIB: # (FAIL) {{.+}}{{\\|/}}Swift.swiftinterface
 CHECK-BROKEN-STDLIB-NOT: {{^}}#
 
-RUN: not %swift_build_sdk_interfaces -sdk %S/Inputs/broken-stdlib-sdk/ -v -o %t/output -skip-stdlib | %FileCheck %s
+RUN: env SWIFT_EXEC=%swiftc_driver_plain not %{python} %utils/swift_build_sdk_interfaces.py %mcp_opt -sdk %S/Inputs/broken-stdlib-sdk/ -v -o %t/output -skip-stdlib | %FileCheck %s
 RUN: %swift_build_sdk_interfaces -sdk %S/Inputs/broken-stdlib-sdk/ -v -o %t/output -skip-stdlib -ignore-non-stdlib-failures | %FileCheck -check-prefix=CHECK-IGNORING-FAILURES %s
diff --git a/test/ModuleInterface/swift_build_sdk_interfaces/xfail-logs.test-sh b/test/ModuleInterface/swift_build_sdk_interfaces/xfail-logs.test-sh
index d6e9aabae4b..d9c8457df68 100644
--- a/test/ModuleInterface/swift_build_sdk_interfaces/xfail-logs.test-sh
+++ b/test/ModuleInterface/swift_build_sdk_interfaces/xfail-logs.test-sh
@@ -1,5 +1,5 @@
 RUN: %empty-directory(%t)
-RUN: not %swift_build_sdk_interfaces -sdk %S/Inputs/xfails-sdk/ -o %t/output -log-path %t/logs | %FileCheck %s
+RUN: env SWIFT_EXEC=%swiftc_driver_plain not %{python} %utils/swift_build_sdk_interfaces.py %mcp_opt -sdk %S/Inputs/xfails-sdk/ -o %t/output -log-path %t/logs | %FileCheck %s
 RUN: %FileCheck -check-prefix PRINTS-ERROR %s < %t/logs/Bad-Bad-err.txt
 
 CHECK: # (FAIL) {{.+}}{{\\|/}}Bad.swiftinterface
@@ -8,7 +8,7 @@ PRINTS-ERROR: unresolved identifier 'garbage'
 
 RUN: %empty-directory(%t)
 RUN: echo '["Good"]' > %t/xfails-good.json
-RUN: not %swift_build_sdk_interfaces -sdk %S/Inputs/xfails-sdk/ -o %t/output -log-path %t/logs -xfails %t/xfails-good.json | %FileCheck -check-prefix=CHECK-XFAIL-GOOD %s
+RUN: env SWIFT_EXEC=%swiftc_driver_plain not %{python} %utils/swift_build_sdk_interfaces.py %mcp_opt -sdk %S/Inputs/xfails-sdk/ -o %t/output -log-path %t/logs -xfails %t/xfails-good.json | %FileCheck -check-prefix=CHECK-XFAIL-GOOD %s
 RUN: %FileCheck -check-prefix PRINTS-ERROR %s < %t/logs/Bad-Bad-err.txt
 
 CHECK-XFAIL-GOOD-DAG: # (FAIL) {{.+}}{{\\|/}}Bad.swiftinterface
@@ -30,7 +30,7 @@ RUN: %FileCheck -check-prefix PRINTS-ERROR %s < %t/logs/Bad-Bad-err.txt
 CHECK-XFAIL-BAD: # (XFAIL) {{.+}}{{\\|/}}Bad.swiftinterface
 
 RUN: %empty-directory(%t)
-RUN: not %swift_build_sdk_interfaces -sdk %t -o %t/output -log-path %t/logs %S/Inputs/xfail-logs-framework/ | %FileCheck -check-prefix=CHECK-FRAMEWORK %s
+RUN: env SWIFT_EXEC=%swiftc_driver_plain not %{python} %utils/swift_build_sdk_interfaces.py %mcp_opt -sdk %t -o %t/output -log-path %t/logs %S/Inputs/xfail-logs-framework/ | %FileCheck -check-prefix=CHECK-FRAMEWORK %s
 RUN: %FileCheck -check-prefix PRINTS-ERROR %s < %t/logs/BadFMWK-x86_64-apple-macos-err.txt
 
 CHECK-FRAMEWORK: # (FAIL) {{.+}}{{\\|/}}BadFMWK.swiftmodule{{\\|/}}x86_64-apple-macos.swiftinterface
diff --git a/test/ModuleInterface/swift_build_sdk_interfaces/xfails.test-sh b/test/ModuleInterface/swift_build_sdk_interfaces/xfails.test-sh
index 6e8f19a2371..b85baf7cd02 100644
--- a/test/ModuleInterface/swift_build_sdk_interfaces/xfails.test-sh
+++ b/test/ModuleInterface/swift_build_sdk_interfaces/xfails.test-sh
@@ -1,7 +1,7 @@
 RUN: %empty-directory(%t)
-RUN: not %swift_build_sdk_interfaces -sdk %S/Inputs/xfails-sdk/ -o %t/output 2> %t/stderr.txt | %FileCheck %s
+RUN: env SWIFT_EXEC=%swiftc_driver_plain not %{python} %utils/swift_build_sdk_interfaces.py %mcp_opt -sdk %S/Inputs/xfails-sdk/ -o %t/output 2> %t/stderr.txt | %FileCheck %s
 RUN: %FileCheck -check-prefix PRINTS-ERROR %s < %t/stderr.txt
-RUN: not %swift_build_sdk_interfaces -sdk %S/Inputs/xfails-sdk/ -v -o %t/output 2> %t/stderr.txt | %FileCheck -check-prefix CHECK-VERBOSE %s
+RUN: env SWIFT_EXEC=%swiftc_driver_plain not %{python} %utils/swift_build_sdk_interfaces.py %mcp_opt -sdk %S/Inputs/xfails-sdk/ -v -o %t/output 2> %t/stderr.txt | %FileCheck -check-prefix CHECK-VERBOSE %s
 RUN: %FileCheck -check-prefix PRINTS-ERROR %s < %t/stderr.txt
 
 CHECK: # (FAIL) {{.+}}{{\\|/}}Bad.swiftinterface
@@ -13,9 +13,9 @@ HIDES-ERROR-NOT: unresolved identifier 'garbage'
 
 RUN: %empty-directory(%t)
 RUN: echo '["Good"]' > %t/xfails-good.json
-RUN: not %swift_build_sdk_interfaces -sdk %S/Inputs/xfails-sdk/ -o %t/output -xfails %t/xfails-good.json 2> %t/stderr.txt | %FileCheck -check-prefix=CHECK-XFAIL-GOOD %s
+RUN: env SWIFT_EXEC=%swiftc_driver_plain not %{python} %utils/swift_build_sdk_interfaces.py %mcp_opt -sdk %S/Inputs/xfails-sdk/ -o %t/output -xfails %t/xfails-good.json 2> %t/stderr.txt | %FileCheck -check-prefix=CHECK-XFAIL-GOOD %s
 RUN: %FileCheck -check-prefix PRINTS-ERROR %s < %t/stderr.txt
-RUN: not %swift_build_sdk_interfaces -sdk %S/Inputs/xfails-sdk/ -v -o %t/output -xfails %t/xfails-good.json 2> %t/stderr.txt | %FileCheck -check-prefix=CHECK-XFAIL-GOOD %s
+RUN: env SWIFT_EXEC=%swiftc_driver_plain not %{python} %utils/swift_build_sdk_interfaces.py %mcp_opt -sdk %S/Inputs/xfails-sdk/ -v -o %t/output -xfails %t/xfails-good.json 2> %t/stderr.txt | %FileCheck -check-prefix=CHECK-XFAIL-GOOD %s
 RUN: %FileCheck -check-prefix PRINTS-ERROR %s < %t/stderr.txt
 
 CHECK-XFAIL-GOOD-DAG: # (FAIL) {{.+}}{{\\|/}}Bad.swiftinterface
diff --git a/test/SILGen/objc_bridging_any.swift b/test/SILGen/objc_bridging_any.swift
index 3a3f9f53f4a..1e1b6a0d04c 100644
--- a/test/SILGen/objc_bridging_any.swift
+++ b/test/SILGen/objc_bridging_any.swift
@@ -690,7 +690,15 @@ class SwiftAnyEnjoyer: NSIdLover, NSIdLoving {
   func takesId(viaProtocol x: Any) { }
 }
 
+enum SillyOptional {
+  case nothing
+  case something(NSObject)
+}
 
+func bridgeNoPayloadEnumCase(_ receiver: NSIdLover) {
+  let value = SillyOptional.nothing
+  receiver.takesId(value)
+}
 
 // CHECK-LABEL: sil_witness_table shared [serialized] GenericOption: Hashable module objc_generics {
 // CHECK-NEXT: base_protocol Equatable: GenericOption: Equatable module objc_generics
diff --git a/test/SourceKit/CursorInfo/cursor_rename.swift b/test/SourceKit/CursorInfo/cursor_rename.swift
index 32344a0734e..9dc350a2f42 100644
--- a/test/SourceKit/CursorInfo/cursor_rename.swift
+++ b/test/SourceKit/CursorInfo/cursor_rename.swift
@@ -18,4 +18,4 @@ _ = Foo.init(2)
 // CHECK1: Rename
 // CHECK2-NOT: Rename
 
-// REQUIRES-ANY: OS=macosx, OS=linux-gnu
\ No newline at end of file
+// REQUIRES: OS=macosx || OS=linux-gnu
diff --git a/test/SourceKit/DocSupport/doc_clang_module.swift b/test/SourceKit/DocSupport/doc_clang_module.swift
index d40aac8ac4a..22be45cc641 100644
--- a/test/SourceKit/DocSupport/doc_clang_module.swift
+++ b/test/SourceKit/DocSupport/doc_clang_module.swift
@@ -1,7 +1,7 @@
 // REQUIRES: objc_interop
 
 // FIXME: the test output we're comparing to is specific to macOS.
-// REQUIRES-ANY: OS=macosx
+// REQUIRES: OS=macosx
 
 // RUN: %empty-directory(%t)
 // RUN: %build-clang-importer-objc-overlays
diff --git a/test/SourceKit/InterfaceGen/gen_clang_module.swift b/test/SourceKit/InterfaceGen/gen_clang_module.swift
index b9cef439699..e6e6bfb89e3 100644
--- a/test/SourceKit/InterfaceGen/gen_clang_module.swift
+++ b/test/SourceKit/InterfaceGen/gen_clang_module.swift
@@ -5,7 +5,7 @@ var x: FooClassBase
 // REQUIRES: objc_interop
 
 // FIXME: the test output we're comparing to is specific to macOS.
-// REQUIRES-ANY: OS=macosx
+// REQUIRES: OS=macosx
 
 // RUN: %empty-directory(%t.overlays)
 // RUN: %empty-directory(%t)
diff --git a/test/SourceKit/InterfaceGen/gen_mixed_module.swift b/test/SourceKit/InterfaceGen/gen_mixed_module.swift
index 0bfd7119ebb..c6c9fe276c1 100644
--- a/test/SourceKit/InterfaceGen/gen_mixed_module.swift
+++ b/test/SourceKit/InterfaceGen/gen_mixed_module.swift
@@ -3,7 +3,7 @@ var x = 10
 // REQUIRES: objc_interop
 
 // FIXME: the test output we're comparing to is specific to macOS.
-// REQUIRES-ANY: OS=macosx
+// REQUIRES: OS=macosx
 
 // RUN: %empty-directory(%t.overlays)
 // RUN: %empty-directory(%t)
diff --git a/test/SourceKit/Refactoring/basic.swift b/test/SourceKit/Refactoring/basic.swift
index b20f674b48a..2a0f0d439a3 100644
--- a/test/SourceKit/Refactoring/basic.swift
+++ b/test/SourceKit/Refactoring/basic.swift
@@ -152,4 +152,4 @@ func foo7() -> String {
 
 // CHECK-LOCALIZE-STRING: source.refactoring.kind.localize.string
 
-// REQUIRES-ANY: OS=macosx, OS=linux-gnu
\ No newline at end of file
+// REQUIRES: OS=macosx || OS=linux-gnu
diff --git a/test/SourceKit/Refactoring/rename-objc.swift b/test/SourceKit/Refactoring/rename-objc.swift
index ac95dc4351f..6cb45bd71e3 100644
--- a/test/SourceKit/Refactoring/rename-objc.swift
+++ b/test/SourceKit/Refactoring/rename-objc.swift
@@ -18,4 +18,4 @@ func foo1() {
 // CHECK2: ACTIONS BEGIN
 // CHECK2-NEXT: ACTIONS END
 
-// REQUIRES-ANY: OS=macosx, OS=linux-gnu
\ No newline at end of file
+// REQUIRES: OS=macosx || OS=linux-gnu
diff --git a/test/SourceKit/Refactoring/semantic-refactoring/expand-default.swift b/test/SourceKit/Refactoring/semantic-refactoring/expand-default.swift
index 92d35368f99..688df4ed9ae 100644
--- a/test/SourceKit/Refactoring/semantic-refactoring/expand-default.swift
+++ b/test/SourceKit/Refactoring/semantic-refactoring/expand-default.swift
@@ -13,4 +13,4 @@ func foo(e : E) {
 // RUN: %sourcekitd-test -req=expand-default -pos=7:7 %s -- %s > %t.result/expand-default.swift.expected
 // RUN: diff -u %S/expand-default.swift.expected %t.result/expand-default.swift.expected
 
-// REQUIRES-ANY: OS=macosx, OS=linux-gnu
+// REQUIRES: OS=macosx || OS=linux-gnu
diff --git a/test/SourceKit/Refactoring/semantic-refactoring/extract-func-default.swift b/test/SourceKit/Refactoring/semantic-refactoring/extract-func-default.swift
index f547b87edab..80fc52ff520 100644
--- a/test/SourceKit/Refactoring/semantic-refactoring/extract-func-default.swift
+++ b/test/SourceKit/Refactoring/semantic-refactoring/extract-func-default.swift
@@ -9,4 +9,4 @@ func foo() -> Int {
 // RUN: diff -u %S/extract-func-default.swift.expected %t.result/extract-func-default.swift.expected
 
 // FIXME: Fails on linux with assertion: "!GlibcModuleMapPath.empty()"" failed
-// REQUIRES-ANY: OS=macosx
+// REQUIRES: OS=macosx
diff --git a/test/SourceKit/Refactoring/semantic-refactoring/extract-func-with-args.swift b/test/SourceKit/Refactoring/semantic-refactoring/extract-func-with-args.swift
index 458690823ce..76a349655f0 100644
--- a/test/SourceKit/Refactoring/semantic-refactoring/extract-func-with-args.swift
+++ b/test/SourceKit/Refactoring/semantic-refactoring/extract-func-with-args.swift
@@ -9,4 +9,4 @@ func foo() -> Int {
 // RUN: diff -u %S/extract-func-with-args.swift.expected %t.result/extract-func-with-args.swift.expected
 
 // FIXME: Fails on linux with assertion: "!GlibcModuleMapPath.empty()"" failed
-// REQUIRES-ANY: OS=macosx
+// REQUIRES: OS=macosx
diff --git a/test/SourceKit/Refactoring/semantic-refactoring/extract-func.swift b/test/SourceKit/Refactoring/semantic-refactoring/extract-func.swift
index c4426191725..c8bbdb82b14 100644
--- a/test/SourceKit/Refactoring/semantic-refactoring/extract-func.swift
+++ b/test/SourceKit/Refactoring/semantic-refactoring/extract-func.swift
@@ -9,4 +9,4 @@ func foo() -> Int {
 // RUN: diff -u %S/extract-func.swift.expected %t.result/extract-func.swift.expected
 
 // FIXME: Fails on linux with assertion: "!GlibcModuleMapPath.empty()"" failed
-// REQUIRES-ANY: OS=macosx
+// REQUIRES: OS=macosx
diff --git a/test/SourceKit/Refactoring/semantic-refactoring/extract-repeated-expression.swift b/test/SourceKit/Refactoring/semantic-refactoring/extract-repeated-expression.swift
index 143c855647e..02ebf45aeb2 100644
--- a/test/SourceKit/Refactoring/semantic-refactoring/extract-repeated-expression.swift
+++ b/test/SourceKit/Refactoring/semantic-refactoring/extract-repeated-expression.swift
@@ -8,4 +8,4 @@ func foo() -> Int {
 // RUN: %sourcekitd-test -req=extract-repeated -pos=3:11 -end-pos 3:12 -name new_name %s -- %s > %t.result/extract-repeated-expression.swift.expected
 // RUN: diff -u %S/extract-repeated-expression.swift.expected %t.result/extract-repeated-expression.swift.expected
 
-// REQUIRES-ANY: OS=macosx, OS=linux-gnu
+// REQUIRES: OS=macosx || OS=linux-gnu
diff --git a/test/SourceKit/Refactoring/semantic-refactoring/fill-stub.swift b/test/SourceKit/Refactoring/semantic-refactoring/fill-stub.swift
index f972d14bc38..87bd053fa6c 100644
--- a/test/SourceKit/Refactoring/semantic-refactoring/fill-stub.swift
+++ b/test/SourceKit/Refactoring/semantic-refactoring/fill-stub.swift
@@ -8,4 +8,4 @@ class C1 : P {}
 // RUN: %sourcekitd-test -req=fill-stub -pos=5:8 %s -- %s > %t.result/fill-stub.swift.expected
 // RUN: diff -u %S/fill-stub.swift.expected %t.result/fill-stub.swift.expected
 
-// REQUIRES-ANY: OS=macosx, OS=linux-gnu
+// REQUIRES: OS=macosx || OS=linux-gnu
diff --git a/test/SourceKit/Refactoring/semantic-refactoring/local-rename.swift b/test/SourceKit/Refactoring/semantic-refactoring/local-rename.swift
index a6664eb151a..587ebcd0b26 100644
--- a/test/SourceKit/Refactoring/semantic-refactoring/local-rename.swift
+++ b/test/SourceKit/Refactoring/semantic-refactoring/local-rename.swift
@@ -19,4 +19,4 @@ func foo() {
 // RUN: %sourcekitd-test -req=find-local-rename-ranges -pos=7:11 %s -- %s > %t.result/local-rename-lazy.swift.expected
 // RUN: diff -u %S/local-rename-lazy.swift.expected %t.result/local-rename-lazy.swift.expected
 
-// REQUIRES-ANY: OS=macosx, OS=linux-gnu
+// REQUIRES: OS=macosx || OS=linux-gnu
diff --git a/test/SourceKit/Refactoring/semantic-refactoring/localize-string.swift b/test/SourceKit/Refactoring/semantic-refactoring/localize-string.swift
index ab53261d7cd..ec207d35438 100644
--- a/test/SourceKit/Refactoring/semantic-refactoring/localize-string.swift
+++ b/test/SourceKit/Refactoring/semantic-refactoring/localize-string.swift
@@ -6,4 +6,4 @@ func foo() -> String {
 // RUN: %sourcekitd-test -req=localize-string -pos=2:10 %s -- %s > %t.result/localize-string.swift.expected
 // RUN: diff -u %S/localize-string.swift.expected %t.result/localize-string.swift.expected
 
-// REQUIRES-ANY: OS=macosx, OS=linux-gnu
+// REQUIRES: OS=macosx || OS=linux-gnu
diff --git a/test/TBD/previous-install-name-map.swift b/test/TBD/previous-install-name-map.swift
index 25bfff72ebb..9099ce5a2f2 100644
--- a/test/TBD/previous-install-name-map.swift
+++ b/test/TBD/previous-install-name-map.swift
@@ -11,3 +11,5 @@
 // CHECK: remark: previous install name for Foo in iOS is /System/Others
 // CHECK: remark: previous install name for Foo in tvOS is /System/Others
 // CHECK: remark: previous install name for Foo in watchOS is /System/Others
+
+// REQUIRES: rdar58569201
diff --git a/tools/SourceKit/lib/SwiftLang/SwiftASTManager.cpp b/tools/SourceKit/lib/SwiftLang/SwiftASTManager.cpp
index 1e2b1fd10a2..1ebbcfeb254 100644
--- a/tools/SourceKit/lib/SwiftLang/SwiftASTManager.cpp
+++ b/tools/SourceKit/lib/SwiftLang/SwiftASTManager.cpp
@@ -539,6 +539,11 @@ bool SwiftASTManager::initCompilerInvocation(
   // We don't care about LLVMArgs
   FrontendOpts.LLVMArgs.clear();
 
+  // This validation may call stat(2) many times. Disable it to prevent
+  // performance issues.
+  Invocation.getSearchPathOptions().DisableModulesValidateSystemDependencies =
+      true;
+
   // SwiftSourceInfo files provide source location information for decls coming
   // from loaded modules. For most IDE use cases it either has an undesirable
   // impact on performance with no benefit (code completion), results in stale
diff --git a/tools/sil-opt/SILOpt.cpp b/tools/sil-opt/SILOpt.cpp
index 410604741a0..d157810f096 100644
--- a/tools/sil-opt/SILOpt.cpp
+++ b/tools/sil-opt/SILOpt.cpp
@@ -450,7 +450,7 @@ int main(int argc, char **argv) {
       auto T = irgen::createIRGenModule(
           SILMod, Invocation.getOutputFilenameForAtMostOnePrimary(),
           Invocation.getMainInputFilenameForDebugInfoForAtMostOnePrimary(),
-          getGlobalLLVMContext());
+          "", getGlobalLLVMContext());
       runCommandLineSelectedPasses(SILMod, T.second);
       irgen::deleteIRGenModule(T);
     }
diff --git a/tools/swift-ide-test/swift-ide-test.cpp b/tools/swift-ide-test/swift-ide-test.cpp
index f09d37aa625..e49842609c5 100644
--- a/tools/swift-ide-test/swift-ide-test.cpp
+++ b/tools/swift-ide-test/swift-ide-test.cpp
@@ -3436,6 +3436,8 @@ int main(int argc, char *argv[]) {
     options::DebugForbidTypecheckPrefix;
   InitInvok.getTypeCheckerOptions().DebugConstraintSolver =
       options::DebugConstraintSolver;
+  InitInvok.getSearchPathOptions().DisableModulesValidateSystemDependencies =
+      true;
 
   for (auto ConfigName : options::BuildConfigs)
     InitInvok.getLangOptions().addCustomConditionalCompilationFlag(ConfigName);
diff --git a/validation-test/stdlib/Glibc.swift b/validation-test/stdlib/Glibc.swift
index 4b1a9351641..70276d29e0b 100644
--- a/validation-test/stdlib/Glibc.swift
+++ b/validation-test/stdlib/Glibc.swift
@@ -6,7 +6,7 @@
 // UNSUPPORTED: OS=tvos
 // UNSUPPORTED: OS=watchos
 
-// REQUIRES-ANY: OS=linux-gnu, OS=linux-androideabi, OS=linux-android
+// REQUIRES: OS=linux-gnu || OS=linux-androideabi || OS=linux-android
 
 import Swift
 import StdlibUnittest
diff --git a/validation-test/stdlib/POSIXErrorCode.swift b/validation-test/stdlib/POSIXErrorCode.swift
index 794425a1e6f..fe60b0c33cf 100644
--- a/validation-test/stdlib/POSIXErrorCode.swift
+++ b/validation-test/stdlib/POSIXErrorCode.swift
@@ -1,7 +1,7 @@
 // RUN: %target-run-simple-swift
 // REQUIRES: executable_test
 //
-// REQUIRES-ANY: OS=macosx, OS=ios, OS=tvos, OS=watchos, OS=linux-androideabi, OS=linux-android, OS=linux-gnu
+// REQUIRES: OS=macosx || OS=ios || OS=tvos || OS=watchos || OS=linux-androideabi || OS=linux-android || OS=linux-gnu
 
 import Swift
 import StdlibUnittest
diff --git a/validation-test/stdlib/StringLowercasedUppercased.swift b/validation-test/stdlib/StringLowercasedUppercased.swift
index 60f92a552e2..7ac789cc922 100644
--- a/validation-test/stdlib/StringLowercasedUppercased.swift
+++ b/validation-test/stdlib/StringLowercasedUppercased.swift
@@ -5,7 +5,7 @@
 // directly.  It is not specific to Linux, it is just that on
 // Apple platforms we are using the NSString bridge right now.
 
-// REQUIRES-ANY: OS=linux-gnu, OS=linux-android, OS=linux-androideabi
+// REQUIRES: OS=linux-gnu || OS=linux-android || OS=linux-androideabi
 
 import StdlibUnittest