Merge clang trunk r238337 from ^/vendor/clang/dist, resolve conflicts,

and preserve our customizations, where necessary.

1 files changed, 541 insertions, 485 deletions

diff --git a/contrib/llvm/tools/clang/lib/CodeGen/CGException.cpp b/contrib/llvm/tools/clang/lib/CodeGen/CGException.cpp
index cb8eb8f..d9a3f0b 100644
--- a/contrib/llvm/tools/clang/lib/CodeGen/CGException.cpp
+++ b/contrib/llvm/tools/clang/lib/CodeGen/CGException.cpp
@@ -16,23 +16,18 @@
 #include "CGCleanup.h"
 #include "CGObjCRuntime.h"
 #include "TargetInfo.h"
+#include "clang/AST/Mangle.h"
 #include "clang/AST/StmtCXX.h"
 #include "clang/AST/StmtObjC.h"
+#include "clang/AST/StmtVisitor.h"
 #include "llvm/IR/CallSite.h"
 #include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/Support/SaveAndRestore.h"
 
 using namespace clang;
 using namespace CodeGen;
 
-static llvm::Constant *getAllocateExceptionFn(CodeGenModule &CGM) {
-  // void *__cxa_allocate_exception(size_t thrown_size);
-
-  llvm::FunctionType *FTy =
-    llvm::FunctionType::get(CGM.Int8PtrTy, CGM.SizeTy, /*IsVarArgs=*/false);
-
-  return CGM.CreateRuntimeFunction(FTy, "__cxa_allocate_exception");
-}
-
 static llvm::Constant *getFreeExceptionFn(CodeGenModule &CGM) {
   // void __cxa_free_exception(void *thrown_exception);
 
@@ -42,44 +37,6 @@ static llvm::Constant *getFreeExceptionFn(CodeGenModule &CGM) {
   return CGM.CreateRuntimeFunction(FTy, "__cxa_free_exception");
 }
 
-static llvm::Constant *getThrowFn(CodeGenModule &CGM) {
-  // void __cxa_throw(void *thrown_exception, std::type_info *tinfo,
-  //                  void (*dest) (void *));
-
-  llvm::Type *Args[3] = { CGM.Int8PtrTy, CGM.Int8PtrTy, CGM.Int8PtrTy };
-  llvm::FunctionType *FTy =
-    llvm::FunctionType::get(CGM.VoidTy, Args, /*IsVarArgs=*/false);
-
-  return CGM.CreateRuntimeFunction(FTy, "__cxa_throw");
-}
-
-static llvm::Constant *getGetExceptionPtrFn(CodeGenModule &CGM) {
-  // void *__cxa_get_exception_ptr(void*);
-
-  llvm::FunctionType *FTy =
-    llvm::FunctionType::get(CGM.Int8PtrTy, CGM.Int8PtrTy, /*IsVarArgs=*/false);
-
-  return CGM.CreateRuntimeFunction(FTy, "__cxa_get_exception_ptr");
-}
-
-static llvm::Constant *getBeginCatchFn(CodeGenModule &CGM) {
-  // void *__cxa_begin_catch(void*);
-
-  llvm::FunctionType *FTy =
-    llvm::FunctionType::get(CGM.Int8PtrTy, CGM.Int8PtrTy, /*IsVarArgs=*/false);
-
-  return CGM.CreateRuntimeFunction(FTy, "__cxa_begin_catch");
-}
-
-static llvm::Constant *getEndCatchFn(CodeGenModule &CGM) {
-  // void __cxa_end_catch();
-
-  llvm::FunctionType *FTy =
-    llvm::FunctionType::get(CGM.VoidTy, /*IsVarArgs=*/false);
-
-  return CGM.CreateRuntimeFunction(FTy, "__cxa_end_catch");
-}
-
 static llvm::Constant *getUnexpectedFn(CodeGenModule &CGM) {
   // void __cxa_call_unexpected(void *thrown_exception);
 
@@ -89,23 +46,30 @@ static llvm::Constant *getUnexpectedFn(CodeGenModule &CGM) {
   return CGM.CreateRuntimeFunction(FTy, "__cxa_call_unexpected");
 }
 
-static llvm::Constant *getTerminateFn(CodeGenModule &CGM) {
+llvm::Constant *CodeGenModule::getTerminateFn() {
   // void __terminate();
 
   llvm::FunctionType *FTy =
-    llvm::FunctionType::get(CGM.VoidTy, /*IsVarArgs=*/false);
+    llvm::FunctionType::get(VoidTy, /*IsVarArgs=*/false);
 
   StringRef name;
 
   // In C++, use std::terminate().
-  if (CGM.getLangOpts().CPlusPlus)
-    name = "_ZSt9terminatev"; // FIXME: mangling!
-  else if (CGM.getLangOpts().ObjC1 &&
-           CGM.getLangOpts().ObjCRuntime.hasTerminate())
+  if (getLangOpts().CPlusPlus &&
+      getTarget().getCXXABI().isItaniumFamily()) {
+    name = "_ZSt9terminatev";
+  } else if (getLangOpts().CPlusPlus &&
+             getTarget().getCXXABI().isMicrosoft()) {
+    if (getLangOpts().isCompatibleWithMSVC(LangOptions::MSVC2015))
+      name = "__std_terminate";
+    else
+      name = "\01?terminate@@YAXXZ";
+  } else if (getLangOpts().ObjC1 &&
+             getLangOpts().ObjCRuntime.hasTerminate())
     name = "objc_terminate";
   else
     name = "abort";
-  return CGM.CreateRuntimeFunction(FTy, name);
+  return CreateRuntimeFunction(FTy, name);
 }
 
 static llvm::Constant *getCatchallRethrowFn(CodeGenModule &CGM,
@@ -126,7 +90,12 @@ namespace {
     // This function must have prototype void(void*).
     const char *CatchallRethrowFn;
 
-    static const EHPersonality &get(CodeGenModule &CGM);
+    static const EHPersonality &get(CodeGenModule &CGM,
+                                    const FunctionDecl *FD);
+    static const EHPersonality &get(CodeGenFunction &CGF) {
+      return get(CGF.CGM, dyn_cast_or_null<FunctionDecl>(CGF.CurCodeDecl));
+    }
+
     static const EHPersonality GNU_C;
     static const EHPersonality GNU_C_SJLJ;
     static const EHPersonality GNU_C_SEH;
@@ -137,6 +106,9 @@ namespace {
     static const EHPersonality GNU_CPlusPlus;
     static const EHPersonality GNU_CPlusPlus_SJLJ;
     static const EHPersonality GNU_CPlusPlus_SEH;
+    static const EHPersonality MSVC_except_handler;
+    static const EHPersonality MSVC_C_specific_handler;
+    static const EHPersonality MSVC_CxxFrameHandler3;
   };
 }
 
@@ -159,6 +131,12 @@ const EHPersonality
 EHPersonality::GNU_ObjCXX = { "__gnustep_objcxx_personality_v0", nullptr };
 const EHPersonality
 EHPersonality::GNUstep_ObjC = { "__gnustep_objc_personality_v0", nullptr };
+const EHPersonality
+EHPersonality::MSVC_except_handler = { "_except_handler3", nullptr };
+const EHPersonality
+EHPersonality::MSVC_C_specific_handler = { "__C_specific_handler", nullptr };
+const EHPersonality
+EHPersonality::MSVC_CxxFrameHandler3 = { "__CxxFrameHandler3", nullptr };
 
 /// On Win64, use libgcc's SEH personality function. We fall back to dwarf on
 /// other platforms, unless the user asked for SjLj exceptions.
@@ -231,9 +209,29 @@ static const EHPersonality &getObjCXXPersonality(const llvm::Triple &T,
   llvm_unreachable("bad runtime kind");
 }
 
-const EHPersonality &EHPersonality::get(CodeGenModule &CGM) {
+static const EHPersonality &getSEHPersonalityMSVC(const llvm::Triple &T) {
+  if (T.getArch() == llvm::Triple::x86)
+    return EHPersonality::MSVC_except_handler;
+  return EHPersonality::MSVC_C_specific_handler;
+}
+
+const EHPersonality &EHPersonality::get(CodeGenModule &CGM,
+                                        const FunctionDecl *FD) {
   const llvm::Triple &T = CGM.getTarget().getTriple();
   const LangOptions &L = CGM.getLangOpts();
+
+  // Try to pick a personality function that is compatible with MSVC if we're
+  // not compiling Obj-C. Obj-C users better have an Obj-C runtime that supports
+  // the GCC-style personality function.
+  if (T.isWindowsMSVCEnvironment() && !L.ObjC1) {
+    if (L.SjLjExceptions)
+      return EHPersonality::GNU_CPlusPlus_SJLJ;
+    else if (FD && FD->usesSEHTry())
+      return getSEHPersonalityMSVC(T);
+    else
+      return EHPersonality::MSVC_CxxFrameHandler3;
+  }
+
   if (L.CPlusPlus && L.ObjC1)
     return getObjCXXPersonality(T, L);
   else if (L.CPlusPlus)
@@ -318,7 +316,7 @@ void CodeGenModule::SimplifyPersonality() {
   if (!LangOpts.ObjCRuntime.isNeXTFamily())
     return;
 
-  const EHPersonality &ObjCXX = EHPersonality::get(*this);
+  const EHPersonality &ObjCXX = EHPersonality::get(*this, /*FD=*/nullptr);
   const EHPersonality &CXX =
       getCXXPersonality(getTarget().getTriple(), LangOpts);
   if (&ObjCXX == &CXX)
@@ -369,17 +367,16 @@ namespace {
 // differs from EmitAnyExprToMem only in that, if a final copy-ctor
 // call is required, an exception within that copy ctor causes
 // std::terminate to be invoked.
-static void EmitAnyExprToExn(CodeGenFunction &CGF, const Expr *e,
-                             llvm::Value *addr) {
+void CodeGenFunction::EmitAnyExprToExn(const Expr *e, llvm::Value *addr) {
   // Make sure the exception object is cleaned up if there's an
   // exception during initialization.
-  CGF.pushFullExprCleanup<FreeException>(EHCleanup, addr);
-  EHScopeStack::stable_iterator cleanup = CGF.EHStack.stable_begin();
+  pushFullExprCleanup<FreeException>(EHCleanup, addr);
+  EHScopeStack::stable_iterator cleanup = EHStack.stable_begin();
 
   // __cxa_allocate_exception returns a void*;  we need to cast this
   // to the appropriate type for the object.
-  llvm::Type *ty = CGF.ConvertTypeForMem(e->getType())->getPointerTo();
-  llvm::Value *typedAddr = CGF.Builder.CreateBitCast(addr, ty);
+  llvm::Type *ty = ConvertTypeForMem(e->getType())->getPointerTo();
+  llvm::Value *typedAddr = Builder.CreateBitCast(addr, ty);
 
   // FIXME: this isn't quite right!  If there's a final unelided call
   // to a copy constructor, then according to [except.terminate]p1 we
@@ -388,11 +385,11 @@ static void EmitAnyExprToExn(CodeGenFunction &CGF, const Expr *e,
   // evaluated but before the exception is caught.  But the best way
   // to handle that is to teach EmitAggExpr to do the final copy
   // differently if it can't be elided.
-  CGF.EmitAnyExprToMem(e, typedAddr, e->getType().getQualifiers(), 
-                       /*IsInit*/ true);
+  EmitAnyExprToMem(e, typedAddr, e->getType().getQualifiers(),
+                   /*IsInit*/ true);
 
   // Deactivate the cleanup block.
-  CGF.DeactivateCleanupBlock(cleanup, cast<llvm::Instruction>(typedAddr));
+  DeactivateCleanupBlock(cleanup, cast<llvm::Instruction>(typedAddr));
 }
 
 llvm::Value *CodeGenFunction::getExceptionSlot() {
@@ -417,67 +414,18 @@ llvm::Value *CodeGenFunction::getSelectorFromSlot() {
 
 void CodeGenFunction::EmitCXXThrowExpr(const CXXThrowExpr *E,
                                        bool KeepInsertionPoint) {
-  if (!E->getSubExpr()) {
-    CGM.getCXXABI().emitRethrow(*this, /*isNoReturn*/true);
-
-    // throw is an expression, and the expression emitters expect us
-    // to leave ourselves at a valid insertion point.
-    if (KeepInsertionPoint)
-      EmitBlock(createBasicBlock("throw.cont"));
-
-    return;
-  }
-
-  if (CGM.getTarget().getTriple().isKnownWindowsMSVCEnvironment()) {
-    ErrorUnsupported(E, "throw expression");
-    return;
-  }
-
-  QualType ThrowType = E->getSubExpr()->getType();
-
-  if (ThrowType->isObjCObjectPointerType()) {
-    const Stmt *ThrowStmt = E->getSubExpr();
-    const ObjCAtThrowStmt S(E->getExprLoc(),
-                            const_cast<Stmt *>(ThrowStmt));
-    CGM.getObjCRuntime().EmitThrowStmt(*this, S, false);
-    // This will clear insertion point which was not cleared in
-    // call to EmitThrowStmt.
-    if (KeepInsertionPoint)
-      EmitBlock(createBasicBlock("throw.cont"));
-    return;
-  }
-  
-  // Now allocate the exception object.
-  llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
-  uint64_t TypeSize = getContext().getTypeSizeInChars(ThrowType).getQuantity();
-
-  llvm::Constant *AllocExceptionFn = getAllocateExceptionFn(CGM);
-  llvm::CallInst *ExceptionPtr =
-    EmitNounwindRuntimeCall(AllocExceptionFn,
-                            llvm::ConstantInt::get(SizeTy, TypeSize),
-                            "exception");
-  
-  EmitAnyExprToExn(*this, E->getSubExpr(), ExceptionPtr);
-
-  // Now throw the exception.
-  llvm::Constant *TypeInfo = CGM.GetAddrOfRTTIDescriptor(ThrowType, 
-                                                         /*ForEH=*/true);
-
-  // The address of the destructor.  If the exception type has a
-  // trivial destructor (or isn't a record), we just pass null.
-  llvm::Constant *Dtor = nullptr;
-  if (const RecordType *RecordTy = ThrowType->getAs<RecordType>()) {
-    CXXRecordDecl *Record = cast<CXXRecordDecl>(RecordTy->getDecl());
-    if (!Record->hasTrivialDestructor()) {
-      CXXDestructorDecl *DtorD = Record->getDestructor();
-      Dtor = CGM.getAddrOfCXXStructor(DtorD, StructorType::Complete);
-      Dtor = llvm::ConstantExpr::getBitCast(Dtor, Int8PtrTy);
+  if (const Expr *SubExpr = E->getSubExpr()) {
+    QualType ThrowType = SubExpr->getType();
+    if (ThrowType->isObjCObjectPointerType()) {
+      const Stmt *ThrowStmt = E->getSubExpr();
+      const ObjCAtThrowStmt S(E->getExprLoc(), const_cast<Stmt *>(ThrowStmt));
+      CGM.getObjCRuntime().EmitThrowStmt(*this, S, false);
+    } else {
+      CGM.getCXXABI().emitThrow(*this, E);
     }
+  } else {
+    CGM.getCXXABI().emitRethrow(*this, /*isNoReturn=*/true);
   }
-  if (!Dtor) Dtor = llvm::Constant::getNullValue(Int8PtrTy);
-
-  llvm::Value *args[] = { ExceptionPtr, TypeInfo, Dtor };
-  EmitNoreturnRuntimeCallOrInvoke(getThrowFn(CGM), args);
 
   // throw is an expression, and the expression emitters expect us
   // to leave ourselves at a valid insertion point.
@@ -509,6 +457,10 @@ void CodeGenFunction::EmitStartEHSpec(const Decl *D) {
       EHStack.pushTerminate();
     }
   } else if (EST == EST_Dynamic || EST == EST_DynamicNone) {
+    // TODO: Revisit exception specifications for the MS ABI.  There is a way to
+    // encode these in an object file but MSVC doesn't do anything with it.
+    if (getTarget().getCXXABI().isMicrosoft())
+      return;
     unsigned NumExceptions = Proto->getNumExceptions();
     EHFilterScope *Filter = EHStack.pushFilter(NumExceptions);
 
@@ -543,8 +495,9 @@ static void emitFilterDispatchBlock(CodeGenFunction &CGF,
 
     llvm::Value *zero = CGF.Builder.getInt32(0);
     llvm::Value *failsFilter =
-      CGF.Builder.CreateICmpSLT(selector, zero, "ehspec.fails");
-    CGF.Builder.CreateCondBr(failsFilter, unexpectedBB, CGF.getEHResumeBlock(false));
+        CGF.Builder.CreateICmpSLT(selector, zero, "ehspec.fails");
+    CGF.Builder.CreateCondBr(failsFilter, unexpectedBB,
+                             CGF.getEHResumeBlock(false));
 
     CGF.EmitBlock(unexpectedBB);
   }
@@ -582,6 +535,10 @@ void CodeGenFunction::EmitEndEHSpec(const Decl *D) {
       EHStack.popTerminate();
     }
   } else if (EST == EST_Dynamic || EST == EST_DynamicNone) {
+    // TODO: Revisit exception specifications for the MS ABI.  There is a way to
+    // encode these in an object file but MSVC doesn't do anything with it.
+    if (getTarget().getCXXABI().isMicrosoft())
+      return;
     EHFilterScope &filterScope = cast<EHFilterScope>(*EHStack.begin());
     emitFilterDispatchBlock(*this, filterScope);
     EHStack.popFilter();
@@ -589,11 +546,6 @@ void CodeGenFunction::EmitEndEHSpec(const Decl *D) {
 }
 
 void CodeGenFunction::EmitCXXTryStmt(const CXXTryStmt &S) {
-  if (CGM.getTarget().getTriple().isKnownWindowsMSVCEnvironment()) {
-    ErrorUnsupported(&S, "try statement");
-    return;
-  }
-
   EnterCXXTryStmt(S);
   EmitStmt(S.getTryBlock());
   ExitCXXTryStmt(S);
@@ -622,7 +574,8 @@ void CodeGenFunction::EnterCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
       if (CaughtType->isObjCObjectPointerType())
         TypeInfo = CGM.getObjCRuntime().GetEHType(CaughtType);
       else
-        TypeInfo = CGM.GetAddrOfRTTIDescriptor(CaughtType, /*ForEH=*/true);
+        TypeInfo =
+            CGM.getAddrOfCXXCatchHandlerType(CaughtType, C->getCaughtType());
       CatchScope->setHandler(I, TypeInfo, Handler);
     } else {
       // No exception decl indicates '...', a catch-all.
@@ -695,8 +648,15 @@ llvm::BasicBlock *CodeGenFunction::getInvokeDestImpl() {
   assert(EHStack.requiresLandingPad());
   assert(!EHStack.empty());
 
-  if (!CGM.getLangOpts().Exceptions)
-    return nullptr;
+  // If exceptions are disabled, there are usually no landingpads. However, when
+  // SEH is enabled, functions using SEH still get landingpads.
+  const LangOptions &LO = CGM.getLangOpts();
+  if (!LO.Exceptions) {
+    if (!LO.Borland && !LO.MicrosoftExt)
+      return nullptr;
+    if (!currentFunctionUsesSEHTry())
+      return nullptr;
+  }
 
   // Check the innermost scope for a cached landing pad.  If this is
   // a non-EH cleanup, we'll check enclosing scopes in EmitLandingPad.
@@ -734,9 +694,9 @@ llvm::BasicBlock *CodeGenFunction::EmitLandingPad() {
 
   // Save the current IR generation state.
   CGBuilderTy::InsertPoint savedIP = Builder.saveAndClearIP();
-  ApplyDebugLocation AutoRestoreLocation(*this, CurEHLocation);
+  auto DL = ApplyDebugLocation::CreateDefaultArtificial(*this, CurEHLocation);
 
-  const EHPersonality &personality = EHPersonality::get(CGM);
+  const EHPersonality &personality = EHPersonality::get(*this);
 
   // Create and configure the landing pad.
   llvm::BasicBlock *lpad = createBasicBlock("lpad");
@@ -762,8 +722,8 @@ llvm::BasicBlock *CodeGenFunction::EmitLandingPad() {
   bool hasFilter = false;
   SmallVector<llvm::Value*, 4> filterTypes;
   llvm::SmallPtrSet<llvm::Value*, 4> catchTypes;
-  for (EHScopeStack::iterator I = EHStack.begin(), E = EHStack.end();
-         I != E; ++I) {
+  for (EHScopeStack::iterator I = EHStack.begin(), E = EHStack.end(); I != E;
+       ++I) {
 
     switch (I->getKind()) {
     case EHScope::Cleanup:
@@ -857,263 +817,6 @@ llvm::BasicBlock *CodeGenFunction::EmitLandingPad() {
   return lpad;
 }
 
-namespace {
-  /// A cleanup to call __cxa_end_catch.  In many cases, the caught
-  /// exception type lets us state definitively that the thrown exception
-  /// type does not have a destructor.  In particular:
-  ///   - Catch-alls tell us nothing, so we have to conservatively
-  ///     assume that the thrown exception might have a destructor.
-  ///   - Catches by reference behave according to their base types.
-  ///   - Catches of non-record types will only trigger for exceptions
-  ///     of non-record types, which never have destructors.
-  ///   - Catches of record types can trigger for arbitrary subclasses
-  ///     of the caught type, so we have to assume the actual thrown
-  ///     exception type might have a throwing destructor, even if the
-  ///     caught type's destructor is trivial or nothrow.
-  struct CallEndCatch : EHScopeStack::Cleanup {
-    CallEndCatch(bool MightThrow) : MightThrow(MightThrow) {}
-    bool MightThrow;
-
-    void Emit(CodeGenFunction &CGF, Flags flags) override {
-      if (!MightThrow) {
-        CGF.EmitNounwindRuntimeCall(getEndCatchFn(CGF.CGM));
-        return;
-      }
-
-      CGF.EmitRuntimeCallOrInvoke(getEndCatchFn(CGF.CGM));
-    }
-  };
-}
-
-/// Emits a call to __cxa_begin_catch and enters a cleanup to call
-/// __cxa_end_catch.
-///
-/// \param EndMightThrow - true if __cxa_end_catch might throw
-static llvm::Value *CallBeginCatch(CodeGenFunction &CGF,
-                                   llvm::Value *Exn,
-                                   bool EndMightThrow) {
-  llvm::CallInst *call =
-    CGF.EmitNounwindRuntimeCall(getBeginCatchFn(CGF.CGM), Exn);
-
-  CGF.EHStack.pushCleanup<CallEndCatch>(NormalAndEHCleanup, EndMightThrow);
-
-  return call;
-}
-
-/// A "special initializer" callback for initializing a catch
-/// parameter during catch initialization.
-static void InitCatchParam(CodeGenFunction &CGF,
-                           const VarDecl &CatchParam,
-                           llvm::Value *ParamAddr,
-                           SourceLocation Loc) {
-  // Load the exception from where the landing pad saved it.
-  llvm::Value *Exn = CGF.getExceptionFromSlot();
-
-  CanQualType CatchType =
-    CGF.CGM.getContext().getCanonicalType(CatchParam.getType());
-  llvm::Type *LLVMCatchTy = CGF.ConvertTypeForMem(CatchType);
-
-  // If we're catching by reference, we can just cast the object
-  // pointer to the appropriate pointer.
-  if (isa<ReferenceType>(CatchType)) {
-    QualType CaughtType = cast<ReferenceType>(CatchType)->getPointeeType();
-    bool EndCatchMightThrow = CaughtType->isRecordType();
-
-    // __cxa_begin_catch returns the adjusted object pointer.
-    llvm::Value *AdjustedExn = CallBeginCatch(CGF, Exn, EndCatchMightThrow);
-
-    // We have no way to tell the personality function that we're
-    // catching by reference, so if we're catching a pointer,
-    // __cxa_begin_catch will actually return that pointer by value.
-    if (const PointerType *PT = dyn_cast<PointerType>(CaughtType)) {
-      QualType PointeeType = PT->getPointeeType();
-
-      // When catching by reference, generally we should just ignore
-      // this by-value pointer and use the exception object instead.
-      if (!PointeeType->isRecordType()) {
-
-        // Exn points to the struct _Unwind_Exception header, which
-        // we have to skip past in order to reach the exception data.
-        unsigned HeaderSize =
-          CGF.CGM.getTargetCodeGenInfo().getSizeOfUnwindException();
-        AdjustedExn = CGF.Builder.CreateConstGEP1_32(Exn, HeaderSize);
-
-      // However, if we're catching a pointer-to-record type that won't
-      // work, because the personality function might have adjusted
-      // the pointer.  There's actually no way for us to fully satisfy
-      // the language/ABI contract here:  we can't use Exn because it
-      // might have the wrong adjustment, but we can't use the by-value
-      // pointer because it's off by a level of abstraction.
-      //
-      // The current solution is to dump the adjusted pointer into an
-      // alloca, which breaks language semantics (because changing the
-      // pointer doesn't change the exception) but at least works.
-      // The better solution would be to filter out non-exact matches
-      // and rethrow them, but this is tricky because the rethrow
-      // really needs to be catchable by other sites at this landing
-      // pad.  The best solution is to fix the personality function.
-      } else {
-        // Pull the pointer for the reference type off.
-        llvm::Type *PtrTy =
-          cast<llvm::PointerType>(LLVMCatchTy)->getElementType();
-
-        // Create the temporary and write the adjusted pointer into it.
-        llvm::Value *ExnPtrTmp = CGF.CreateTempAlloca(PtrTy, "exn.byref.tmp");
-        llvm::Value *Casted = CGF.Builder.CreateBitCast(AdjustedExn, PtrTy);
-        CGF.Builder.CreateStore(Casted, ExnPtrTmp);
-
-        // Bind the reference to the temporary.
-        AdjustedExn = ExnPtrTmp;
-      }
-    }
-
-    llvm::Value *ExnCast =
-      CGF.Builder.CreateBitCast(AdjustedExn, LLVMCatchTy, "exn.byref");
-    CGF.Builder.CreateStore(ExnCast, ParamAddr);
-    return;
-  }
-
-  // Scalars and complexes.
-  TypeEvaluationKind TEK = CGF.getEvaluationKind(CatchType);
-  if (TEK != TEK_Aggregate) {
-    llvm::Value *AdjustedExn = CallBeginCatch(CGF, Exn, false);
-    
-    // If the catch type is a pointer type, __cxa_begin_catch returns
-    // the pointer by value.
-    if (CatchType->hasPointerRepresentation()) {
-      llvm::Value *CastExn =
-        CGF.Builder.CreateBitCast(AdjustedExn, LLVMCatchTy, "exn.casted");
-
-      switch (CatchType.getQualifiers().getObjCLifetime()) {
-      case Qualifiers::OCL_Strong:
-        CastExn = CGF.EmitARCRetainNonBlock(CastExn);
-        // fallthrough
-
-      case Qualifiers::OCL_None:
-      case Qualifiers::OCL_ExplicitNone:
-      case Qualifiers::OCL_Autoreleasing:
-        CGF.Builder.CreateStore(CastExn, ParamAddr);
-        return;
-
-      case Qualifiers::OCL_Weak:
-        CGF.EmitARCInitWeak(ParamAddr, CastExn);
-        return;
-      }
-      llvm_unreachable("bad ownership qualifier!");
-    }
-
-    // Otherwise, it returns a pointer into the exception object.
-
-    llvm::Type *PtrTy = LLVMCatchTy->getPointerTo(0); // addrspace 0 ok
-    llvm::Value *Cast = CGF.Builder.CreateBitCast(AdjustedExn, PtrTy);
-
-    LValue srcLV = CGF.MakeNaturalAlignAddrLValue(Cast, CatchType);
-    LValue destLV = CGF.MakeAddrLValue(ParamAddr, CatchType,
-                                  CGF.getContext().getDeclAlign(&CatchParam));
-    switch (TEK) {
-    case TEK_Complex:
-      CGF.EmitStoreOfComplex(CGF.EmitLoadOfComplex(srcLV, Loc), destLV,
-                             /*init*/ true);
-      return;
-    case TEK_Scalar: {
-      llvm::Value *ExnLoad = CGF.EmitLoadOfScalar(srcLV, Loc);
-      CGF.EmitStoreOfScalar(ExnLoad, destLV, /*init*/ true);
-      return;
-    }
-    case TEK_Aggregate:
-      llvm_unreachable("evaluation kind filtered out!");
-    }
-    llvm_unreachable("bad evaluation kind");
-  }
-
-  assert(isa<RecordType>(CatchType) && "unexpected catch type!");
-
-  llvm::Type *PtrTy = LLVMCatchTy->getPointerTo(0); // addrspace 0 ok
-
-  // Check for a copy expression.  If we don't have a copy expression,
-  // that means a trivial copy is okay.
-  const Expr *copyExpr = CatchParam.getInit();
-  if (!copyExpr) {
-    llvm::Value *rawAdjustedExn = CallBeginCatch(CGF, Exn, true);
-    llvm::Value *adjustedExn = CGF.Builder.CreateBitCast(rawAdjustedExn, PtrTy);
-    CGF.EmitAggregateCopy(ParamAddr, adjustedExn, CatchType);
-    return;
-  }
-
-  // We have to call __cxa_get_exception_ptr to get the adjusted
-  // pointer before copying.
-  llvm::CallInst *rawAdjustedExn =
-    CGF.EmitNounwindRuntimeCall(getGetExceptionPtrFn(CGF.CGM), Exn);
-
-  // Cast that to the appropriate type.
-  llvm::Value *adjustedExn = CGF.Builder.CreateBitCast(rawAdjustedExn, PtrTy);
-
-  // The copy expression is defined in terms of an OpaqueValueExpr.
-  // Find it and map it to the adjusted expression.
-  CodeGenFunction::OpaqueValueMapping
-    opaque(CGF, OpaqueValueExpr::findInCopyConstruct(copyExpr),
-           CGF.MakeAddrLValue(adjustedExn, CatchParam.getType()));
-
-  // Call the copy ctor in a terminate scope.
-  CGF.EHStack.pushTerminate();
-
-  // Perform the copy construction.
-  CharUnits Alignment = CGF.getContext().getDeclAlign(&CatchParam);
-  CGF.EmitAggExpr(copyExpr,
-                  AggValueSlot::forAddr(ParamAddr, Alignment, Qualifiers(),
-                                        AggValueSlot::IsNotDestructed,
-                                        AggValueSlot::DoesNotNeedGCBarriers,
-                                        AggValueSlot::IsNotAliased));
-
-  // Leave the terminate scope.
-  CGF.EHStack.popTerminate();
-
-  // Undo the opaque value mapping.
-  opaque.pop();
-
-  // Finally we can call __cxa_begin_catch.
-  CallBeginCatch(CGF, Exn, true);
-}
-
-/// Begins a catch statement by initializing the catch variable and
-/// calling __cxa_begin_catch.
-static void BeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *S) {
-  // We have to be very careful with the ordering of cleanups here:
-  //   C++ [except.throw]p4:
-  //     The destruction [of the exception temporary] occurs
-  //     immediately after the destruction of the object declared in
-  //     the exception-declaration in the handler.
-  //
-  // So the precise ordering is:
-  //   1.  Construct catch variable.
-  //   2.  __cxa_begin_catch
-  //   3.  Enter __cxa_end_catch cleanup
-  //   4.  Enter dtor cleanup
-  //
-  // We do this by using a slightly abnormal initialization process.
-  // Delegation sequence:
-  //   - ExitCXXTryStmt opens a RunCleanupsScope
-  //     - EmitAutoVarAlloca creates the variable and debug info
-  //       - InitCatchParam initializes the variable from the exception
-  //       - CallBeginCatch calls __cxa_begin_catch
-  //       - CallBeginCatch enters the __cxa_end_catch cleanup
-  //     - EmitAutoVarCleanups enters the variable destructor cleanup
-  //   - EmitCXXTryStmt emits the code for the catch body
-  //   - EmitCXXTryStmt close the RunCleanupsScope
-
-  VarDecl *CatchParam = S->getExceptionDecl();
-  if (!CatchParam) {
-    llvm::Value *Exn = CGF.getExceptionFromSlot();
-    CallBeginCatch(CGF, Exn, true);
-    return;
-  }
-
-  // Emit the local.
-  CodeGenFunction::AutoVarEmission var = CGF.EmitAutoVarAlloca(*CatchParam);
-  InitCatchParam(CGF, *CatchParam, var.getObjectAddress(CGF), S->getLocStart());
-  CGF.EmitAutoVarCleanups(var);
-}
-
 /// Emit the structure of the dispatch block for the given catch scope.
 /// It is an invariant that the dispatch block already exists.
 static void emitCatchDispatchBlock(CodeGenFunction &CGF,
@@ -1252,11 +955,10 @@ void CodeGenFunction::ExitCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
     RunCleanupsScope CatchScope(*this);
 
     // Initialize the catch variable and set up the cleanups.
-    BeginCatch(*this, C);
+    CGM.getCXXABI().emitBeginCatch(*this, C);
 
     // Emit the PGO counter increment.
-    RegionCounter CatchCnt = getPGORegionCounter(C);
-    CatchCnt.beginRegion(Builder);
+    incrementProfileCounter(C);
 
     // Perform the body of the catch.
     EmitStmt(C->getHandlerBlock());
@@ -1284,9 +986,8 @@ void CodeGenFunction::ExitCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
       Builder.CreateBr(ContBB);
   }
 
-  RegionCounter ContCnt = getPGORegionCounter(&S);
   EmitBlock(ContBB);
-  ContCnt.beginRegion(Builder);
+  incrementProfileCounter(&S);
 }
 
 namespace {
@@ -1480,68 +1181,6 @@ void CodeGenFunction::FinallyInfo::exit(CodeGenFunction &CGF) {
   CGF.PopCleanupBlock();
 }
 
-/// In a terminate landing pad, should we use __clang__call_terminate
-/// or just a naked call to std::terminate?
-///
-/// __clang_call_terminate calls __cxa_begin_catch, which then allows
-/// std::terminate to usefully report something about the
-/// violating exception.
-static bool useClangCallTerminate(CodeGenModule &CGM) {
-  // Only do this for Itanium-family ABIs in C++ mode.
-  return (CGM.getLangOpts().CPlusPlus &&
-          CGM.getTarget().getCXXABI().isItaniumFamily());
-}
-
-/// Get or define the following function:
-///   void @__clang_call_terminate(i8* %exn) nounwind noreturn
-/// This code is used only in C++.
-static llvm::Constant *getClangCallTerminateFn(CodeGenModule &CGM) {
-  llvm::FunctionType *fnTy =
-    llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*IsVarArgs=*/false);
-  llvm::Constant *fnRef =
-    CGM.CreateRuntimeFunction(fnTy, "__clang_call_terminate");
-
-  llvm::Function *fn = dyn_cast<llvm::Function>(fnRef);
-  if (fn && fn->empty()) {
-    fn->setDoesNotThrow();
-    fn->setDoesNotReturn();
-
-    // What we really want is to massively penalize inlining without
-    // forbidding it completely.  The difference between that and
-    // 'noinline' is negligible.
-    fn->addFnAttr(llvm::Attribute::NoInline);
-
-    // Allow this function to be shared across translation units, but
-    // we don't want it to turn into an exported symbol.
-    fn->setLinkage(llvm::Function::LinkOnceODRLinkage);
-    fn->setVisibility(llvm::Function::HiddenVisibility);
-
-    // Set up the function.
-    llvm::BasicBlock *entry =
-      llvm::BasicBlock::Create(CGM.getLLVMContext(), "", fn);
-    CGBuilderTy builder(entry);
-
-    // Pull the exception pointer out of the parameter list.
-    llvm::Value *exn = &*fn->arg_begin();
-
-    // Call __cxa_begin_catch(exn).
-    llvm::CallInst *catchCall = builder.CreateCall(getBeginCatchFn(CGM), exn);
-    catchCall->setDoesNotThrow();
-    catchCall->setCallingConv(CGM.getRuntimeCC());
-
-    // Call std::terminate().
-    llvm::CallInst *termCall = builder.CreateCall(getTerminateFn(CGM));
-    termCall->setDoesNotThrow();
-    termCall->setDoesNotReturn();
-    termCall->setCallingConv(CGM.getRuntimeCC());
-
-    // std::terminate cannot return.
-    builder.CreateUnreachable();
-  }
-
-  return fnRef;
-}
-
 llvm::BasicBlock *CodeGenFunction::getTerminateLandingPad() {
   if (TerminateLandingPad)
     return TerminateLandingPad;
@@ -1553,20 +1192,17 @@ llvm::BasicBlock *CodeGenFunction::getTerminateLandingPad() {
   Builder.SetInsertPoint(TerminateLandingPad);
 
   // Tell the backend that this is a landing pad.
-  const EHPersonality &Personality = EHPersonality::get(CGM);
+  const EHPersonality &Personality = EHPersonality::get(*this);
   llvm::LandingPadInst *LPadInst =
     Builder.CreateLandingPad(llvm::StructType::get(Int8PtrTy, Int32Ty, nullptr),
                              getOpaquePersonalityFn(CGM, Personality), 0);
   LPadInst->addClause(getCatchAllValue(*this));
 
-  llvm::CallInst *terminateCall;
-  if (useClangCallTerminate(CGM)) {
-    // Extract out the exception pointer.
-    llvm::Value *exn = Builder.CreateExtractValue(LPadInst, 0);
-    terminateCall = EmitNounwindRuntimeCall(getClangCallTerminateFn(CGM), exn);
-  } else {
-    terminateCall = EmitNounwindRuntimeCall(getTerminateFn(CGM));
-  }
+  llvm::Value *Exn = 0;
+  if (getLangOpts().CPlusPlus)
+    Exn = Builder.CreateExtractValue(LPadInst, 0);
+  llvm::CallInst *terminateCall =
+      CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
   terminateCall->setDoesNotReturn();
   Builder.CreateUnreachable();
 
@@ -1586,14 +1222,11 @@ llvm::BasicBlock *CodeGenFunction::getTerminateHandler() {
   // end of the function by FinishFunction.
   TerminateHandler = createBasicBlock("terminate.handler");
   Builder.SetInsertPoint(TerminateHandler);
-  llvm::CallInst *terminateCall;
-  if (useClangCallTerminate(CGM)) {
-    // Load the exception pointer.
-    llvm::Value *exn = getExceptionFromSlot();
-    terminateCall = EmitNounwindRuntimeCall(getClangCallTerminateFn(CGM), exn);
-  } else {
-    terminateCall = EmitNounwindRuntimeCall(getTerminateFn(CGM));
-  }
+  llvm::Value *Exn = 0;
+  if (getLangOpts().CPlusPlus)
+    Exn = getExceptionFromSlot();
+  llvm::CallInst *terminateCall =
+      CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
   terminateCall->setDoesNotReturn();
   Builder.CreateUnreachable();
 
@@ -1612,15 +1245,14 @@ llvm::BasicBlock *CodeGenFunction::getEHResumeBlock(bool isCleanup) {
   EHResumeBlock = createBasicBlock("eh.resume");
   Builder.SetInsertPoint(EHResumeBlock);
 
-  const EHPersonality &Personality = EHPersonality::get(CGM);
+  const EHPersonality &Personality = EHPersonality::get(*this);
 
   // This can always be a call because we necessarily didn't find
   // anything on the EH stack which needs our help.
   const char *RethrowName = Personality.CatchallRethrowFn;
   if (RethrowName != nullptr && !isCleanup) {
     EmitRuntimeCall(getCatchallRethrowFn(CGM, RethrowName),
-                    getExceptionFromSlot())
-      ->setDoesNotReturn();
+                    getExceptionFromSlot())->setDoesNotReturn();
     Builder.CreateUnreachable();
     Builder.restoreIP(SavedIP);
     return EHResumeBlock;
@@ -1642,9 +1274,433 @@ llvm::BasicBlock *CodeGenFunction::getEHResumeBlock(bool isCleanup) {
 }
 
 void CodeGenFunction::EmitSEHTryStmt(const SEHTryStmt &S) {
-  CGM.ErrorUnsupported(&S, "SEH __try");
+  // FIXME: Implement SEH on other architectures.
+  const llvm::Triple &T = CGM.getTarget().getTriple();
+  if (T.getArch() != llvm::Triple::x86_64 ||
+      !T.isKnownWindowsMSVCEnvironment()) {
+    ErrorUnsupported(&S, "__try statement");
+    return;
+  }
+
+  EnterSEHTryStmt(S);
+  {
+    JumpDest TryExit = getJumpDestInCurrentScope("__try.__leave");
+
+    SEHTryEpilogueStack.push_back(&TryExit);
+    EmitStmt(S.getTryBlock());
+    SEHTryEpilogueStack.pop_back();
+
+    if (!TryExit.getBlock()->use_empty())
+      EmitBlock(TryExit.getBlock(), /*IsFinished=*/true);
+    else
+      delete TryExit.getBlock();
+  }
+  ExitSEHTryStmt(S);
+}
+
+namespace {
+struct PerformSEHFinally : EHScopeStack::Cleanup {
+  llvm::Function *OutlinedFinally;
+  PerformSEHFinally(llvm::Function *OutlinedFinally)
+      : OutlinedFinally(OutlinedFinally) {}
+
+  void Emit(CodeGenFunction &CGF, Flags F) override {
+    ASTContext &Context = CGF.getContext();
+    QualType ArgTys[2] = {Context.UnsignedCharTy, Context.VoidPtrTy};
+    FunctionProtoType::ExtProtoInfo EPI;
+    const auto *FTP = cast<FunctionType>(
+        Context.getFunctionType(Context.VoidTy, ArgTys, EPI));
+
+    CallArgList Args;
+    llvm::Value *IsForEH =
+        llvm::ConstantInt::get(CGF.ConvertType(ArgTys[0]), F.isForEHCleanup());
+    Args.add(RValue::get(IsForEH), ArgTys[0]);
+
+    CodeGenModule &CGM = CGF.CGM;
+    llvm::Value *Zero = llvm::ConstantInt::get(CGM.Int32Ty, 0);
+    llvm::Value *FrameAddr = CGM.getIntrinsic(llvm::Intrinsic::frameaddress);
+    llvm::Value *FP = CGF.Builder.CreateCall(FrameAddr, Zero);
+    Args.add(RValue::get(FP), ArgTys[1]);
+
+    const CGFunctionInfo &FnInfo =
+        CGM.getTypes().arrangeFreeFunctionCall(Args, FTP, /*chainCall=*/false);
+    CGF.EmitCall(FnInfo, OutlinedFinally, ReturnValueSlot(), Args);
+  }
+};
+}
+
+namespace {
+/// Find all local variable captures in the statement.
+struct CaptureFinder : ConstStmtVisitor<CaptureFinder> {
+  CodeGenFunction &ParentCGF;
+  const VarDecl *ParentThis;
+  SmallVector<const VarDecl *, 4> Captures;
+  CaptureFinder(CodeGenFunction &ParentCGF, const VarDecl *ParentThis)
+      : ParentCGF(ParentCGF), ParentThis(ParentThis) {}
+
+  void Visit(const Stmt *S) {
+    // See if this is a capture, then recurse.
+    ConstStmtVisitor<CaptureFinder>::Visit(S);
+    for (const Stmt *Child : S->children())
+      if (Child)
+        Visit(Child);
+  }
+
+  void VisitDeclRefExpr(const DeclRefExpr *E) {
+    // If this is already a capture, just make sure we capture 'this'.
+    if (E->refersToEnclosingVariableOrCapture()) {
+      Captures.push_back(ParentThis);
+      return;
+    }
+
+    const auto *D = dyn_cast<VarDecl>(E->getDecl());
+    if (D && D->isLocalVarDeclOrParm() && D->hasLocalStorage())
+      Captures.push_back(D);
+  }
+
+  void VisitCXXThisExpr(const CXXThisExpr *E) {
+    Captures.push_back(ParentThis);
+  }
+};
+}
+
+void CodeGenFunction::EmitCapturedLocals(CodeGenFunction &ParentCGF,
+                                         const Stmt *OutlinedStmt,
+                                         llvm::Value *ParentFP) {
+  // Find all captures in the Stmt.
+  CaptureFinder Finder(ParentCGF, ParentCGF.CXXABIThisDecl);
+  Finder.Visit(OutlinedStmt);
+
+  // Typically there are no captures and we can exit early.
+  if (Finder.Captures.empty())
+    return;
+
+  // Prepare the first two arguments to llvm.framerecover.
+  llvm::Function *FrameRecoverFn = llvm::Intrinsic::getDeclaration(
+      &CGM.getModule(), llvm::Intrinsic::framerecover);
+  llvm::Constant *ParentI8Fn =
+      llvm::ConstantExpr::getBitCast(ParentCGF.CurFn, Int8PtrTy);
+
+  // Create llvm.framerecover calls for all captures.
+  for (const VarDecl *VD : Finder.Captures) {
+    if (isa<ImplicitParamDecl>(VD)) {
+      CGM.ErrorUnsupported(VD, "'this' captured by SEH");
+      CXXThisValue = llvm::UndefValue::get(ConvertTypeForMem(VD->getType()));
+      continue;
+    }
+    if (VD->getType()->isVariablyModifiedType()) {
+      CGM.ErrorUnsupported(VD, "VLA captured by SEH");
+      continue;
+    }
+    assert((isa<ImplicitParamDecl>(VD) || VD->isLocalVarDeclOrParm()) &&
+           "captured non-local variable");
+
+    // If this decl hasn't been declared yet, it will be declared in the
+    // OutlinedStmt.
+    auto I = ParentCGF.LocalDeclMap.find(VD);
+    if (I == ParentCGF.LocalDeclMap.end())
+      continue;
+    llvm::Value *ParentVar = I->second;
+
+    llvm::CallInst *RecoverCall = nullptr;
+    CGBuilderTy Builder(AllocaInsertPt);
+    if (auto *ParentAlloca = dyn_cast<llvm::AllocaInst>(ParentVar)) {
+      // Mark the variable escaped if nobody else referenced it and compute the
+      // frameescape index.
+      auto InsertPair =
+          ParentCGF.EscapedLocals.insert(std::make_pair(ParentAlloca, -1));
+      if (InsertPair.second)
+        InsertPair.first->second = ParentCGF.EscapedLocals.size() - 1;
+      int FrameEscapeIdx = InsertPair.first->second;
+      // call i8* @llvm.framerecover(i8* bitcast(@parentFn), i8* %fp, i32 N)
+      RecoverCall = Builder.CreateCall(
+          FrameRecoverFn, {ParentI8Fn, ParentFP,
+                           llvm::ConstantInt::get(Int32Ty, FrameEscapeIdx)});
+
+    } else {
+      // If the parent didn't have an alloca, we're doing some nested outlining.
+      // Just clone the existing framerecover call, but tweak the FP argument to
+      // use our FP value. All other arguments are constants.
+      auto *ParentRecover =
+          cast<llvm::IntrinsicInst>(ParentVar->stripPointerCasts());
+      assert(ParentRecover->getIntrinsicID() == llvm::Intrinsic::framerecover &&
+             "expected alloca or framerecover in parent LocalDeclMap");
+      RecoverCall = cast<llvm::CallInst>(ParentRecover->clone());
+      RecoverCall->setArgOperand(1, ParentFP);
+      RecoverCall->insertBefore(AllocaInsertPt);
+    }
+
+    // Bitcast the variable, rename it, and insert it in the local decl map.
+    llvm::Value *ChildVar =
+        Builder.CreateBitCast(RecoverCall, ParentVar->getType());
+    ChildVar->setName(ParentVar->getName());
+    LocalDeclMap[VD] = ChildVar;
+  }
+}
+
+/// Arrange a function prototype that can be called by Windows exception
+/// handling personalities. On Win64, the prototype looks like:
+/// RetTy func(void *EHPtrs, void *ParentFP);
+void CodeGenFunction::startOutlinedSEHHelper(CodeGenFunction &ParentCGF,
+                                             StringRef Name, QualType RetTy,
+                                             FunctionArgList &Args,
+                                             const Stmt *OutlinedStmt) {
+  llvm::Function *ParentFn = ParentCGF.CurFn;
+  const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeFreeFunctionDeclaration(
+      RetTy, Args, FunctionType::ExtInfo(), /*isVariadic=*/false);
+
+  llvm::FunctionType *FnTy = CGM.getTypes().GetFunctionType(FnInfo);
+  llvm::Function *Fn = llvm::Function::Create(
+      FnTy, llvm::GlobalValue::InternalLinkage, Name.str(), &CGM.getModule());
+  // The filter is either in the same comdat as the function, or it's internal.
+  if (llvm::Comdat *C = ParentFn->getComdat()) {
+    Fn->setComdat(C);
+  } else if (ParentFn->hasWeakLinkage() || ParentFn->hasLinkOnceLinkage()) {
+    llvm::Comdat *C = CGM.getModule().getOrInsertComdat(ParentFn->getName());
+    ParentFn->setComdat(C);
+    Fn->setComdat(C);
+  } else {
+    Fn->setLinkage(llvm::GlobalValue::InternalLinkage);
+  }
+
+  IsOutlinedSEHHelper = true;
+
+  StartFunction(GlobalDecl(), RetTy, Fn, FnInfo, Args,
+                OutlinedStmt->getLocStart(), OutlinedStmt->getLocStart());
+
+  CGM.SetLLVMFunctionAttributes(nullptr, FnInfo, CurFn);
+
+  auto AI = Fn->arg_begin();
+  ++AI;
+  EmitCapturedLocals(ParentCGF, OutlinedStmt, &*AI);
+}
+
+/// Create a stub filter function that will ultimately hold the code of the
+/// filter expression. The EH preparation passes in LLVM will outline the code
+/// from the main function body into this stub.
+llvm::Function *
+CodeGenFunction::GenerateSEHFilterFunction(CodeGenFunction &ParentCGF,
+                                           const SEHExceptStmt &Except) {
+  const Expr *FilterExpr = Except.getFilterExpr();
+  SourceLocation StartLoc = FilterExpr->getLocStart();
+
+  SEHPointersDecl = ImplicitParamDecl::Create(
+      getContext(), nullptr, StartLoc,
+      &getContext().Idents.get("exception_pointers"), getContext().VoidPtrTy);
+  FunctionArgList Args;
+  Args.push_back(SEHPointersDecl);
+  Args.push_back(ImplicitParamDecl::Create(
+      getContext(), nullptr, StartLoc,
+      &getContext().Idents.get("frame_pointer"), getContext().VoidPtrTy));
+
+  // Get the mangled function name.
+  SmallString<128> Name;
+  {
+    llvm::raw_svector_ostream OS(Name);
+    const Decl *ParentCodeDecl = ParentCGF.CurCodeDecl;
+    const NamedDecl *Parent = dyn_cast_or_null<NamedDecl>(ParentCodeDecl);
+    assert(Parent && "FIXME: handle unnamed decls (lambdas, blocks) with SEH");
+    CGM.getCXXABI().getMangleContext().mangleSEHFilterExpression(Parent, OS);
+  }
+
+  startOutlinedSEHHelper(ParentCGF, Name, getContext().LongTy, Args,
+                         FilterExpr);
+
+  // Mark finally block calls as nounwind and noinline to make LLVM's job a
+  // little easier.
+  // FIXME: Remove these restrictions in the future.
+  CurFn->addFnAttr(llvm::Attribute::NoUnwind);
+  CurFn->addFnAttr(llvm::Attribute::NoInline);
+
+  EmitSEHExceptionCodeSave();
+
+  // Emit the original filter expression, convert to i32, and return.
+  llvm::Value *R = EmitScalarExpr(FilterExpr);
+  R = Builder.CreateIntCast(R, ConvertType(getContext().LongTy),
+                            FilterExpr->getType()->isSignedIntegerType());
+  Builder.CreateStore(R, ReturnValue);
+
+  FinishFunction(FilterExpr->getLocEnd());
+
+  return CurFn;
+}
+
+llvm::Function *
+CodeGenFunction::GenerateSEHFinallyFunction(CodeGenFunction &ParentCGF,
+                                            const SEHFinallyStmt &Finally) {
+  const Stmt *FinallyBlock = Finally.getBlock();
+  SourceLocation StartLoc = FinallyBlock->getLocStart();
+
+  FunctionArgList Args;
+  Args.push_back(ImplicitParamDecl::Create(
+      getContext(), nullptr, StartLoc,
+      &getContext().Idents.get("abnormal_termination"),
+      getContext().UnsignedCharTy));
+  Args.push_back(ImplicitParamDecl::Create(
+      getContext(), nullptr, StartLoc,
+      &getContext().Idents.get("frame_pointer"), getContext().VoidPtrTy));
+
+  // Get the mangled function name.
+  SmallString<128> Name;
+  {
+    llvm::raw_svector_ostream OS(Name);
+    const Decl *ParentCodeDecl = ParentCGF.CurCodeDecl;
+    const NamedDecl *Parent = dyn_cast_or_null<NamedDecl>(ParentCodeDecl);
+    assert(Parent && "FIXME: handle unnamed decls (lambdas, blocks) with SEH");
+    CGM.getCXXABI().getMangleContext().mangleSEHFinallyBlock(Parent, OS);
+  }
+
+  startOutlinedSEHHelper(ParentCGF, Name, getContext().VoidTy, Args,
+                         FinallyBlock);
+
+  // Emit the original filter expression, convert to i32, and return.
+  EmitStmt(FinallyBlock);
+
+  FinishFunction(FinallyBlock->getLocEnd());
+
+  return CurFn;
+}
+
+void CodeGenFunction::EmitSEHExceptionCodeSave() {
+  // Save the exception code in the exception slot to unify exception access in
+  // the filter function and the landing pad.
+  // struct EXCEPTION_POINTERS {
+  //   EXCEPTION_RECORD *ExceptionRecord;
+  //   CONTEXT *ContextRecord;
+  // };
+  // void *exn.slot =
+  //     (void *)(uintptr_t)exception_pointers->ExceptionRecord->ExceptionCode;
+  llvm::Value *Ptrs = Builder.CreateLoad(GetAddrOfLocalVar(SEHPointersDecl));
+  llvm::Type *RecordTy = CGM.Int32Ty->getPointerTo();
+  llvm::Type *PtrsTy = llvm::StructType::get(RecordTy, CGM.VoidPtrTy, nullptr);
+  Ptrs = Builder.CreateBitCast(Ptrs, PtrsTy->getPointerTo());
+  llvm::Value *Rec = Builder.CreateStructGEP(PtrsTy, Ptrs, 0);
+  Rec = Builder.CreateLoad(Rec);
+  llvm::Value *Code = Builder.CreateLoad(Rec);
+  Code = Builder.CreateZExt(Code, CGM.IntPtrTy);
+  // FIXME: Change landing pads to produce {i32, i32} and make the exception
+  // slot an i32.
+  Code = Builder.CreateIntToPtr(Code, CGM.VoidPtrTy);
+  Builder.CreateStore(Code, getExceptionSlot());
+}
+
+llvm::Value *CodeGenFunction::EmitSEHExceptionInfo() {
+  // Sema should diagnose calling this builtin outside of a filter context, but
+  // don't crash if we screw up.
+  if (!SEHPointersDecl)
+    return llvm::UndefValue::get(Int8PtrTy);
+  return Builder.CreateLoad(GetAddrOfLocalVar(SEHPointersDecl));
+}
+
+llvm::Value *CodeGenFunction::EmitSEHExceptionCode() {
+  // If we're in a landing pad or filter function, the exception slot contains
+  // the code.
+  assert(ExceptionSlot);
+  llvm::Value *Code =
+      Builder.CreatePtrToInt(getExceptionFromSlot(), CGM.IntPtrTy);
+  return Builder.CreateTrunc(Code, CGM.Int32Ty);
+}
+
+llvm::Value *CodeGenFunction::EmitSEHAbnormalTermination() {
+  // Abnormal termination is just the first parameter to the outlined finally
+  // helper.
+  auto AI = CurFn->arg_begin();
+  return Builder.CreateZExt(&*AI, Int32Ty);
+}
+
+void CodeGenFunction::EnterSEHTryStmt(const SEHTryStmt &S) {
+  CodeGenFunction HelperCGF(CGM, /*suppressNewContext=*/true);
+  if (const SEHFinallyStmt *Finally = S.getFinallyHandler()) {
+    // Push a cleanup for __finally blocks.
+    llvm::Function *FinallyFunc =
+        HelperCGF.GenerateSEHFinallyFunction(*this, *Finally);
+    EHStack.pushCleanup<PerformSEHFinally>(NormalAndEHCleanup, FinallyFunc);
+    return;
+  }
+
+  // Otherwise, we must have an __except block.
+  const SEHExceptStmt *Except = S.getExceptHandler();
+  assert(Except);
+  EHCatchScope *CatchScope = EHStack.pushCatch(1);
+
+  // If the filter is known to evaluate to 1, then we can use the clause "catch
+  // i8* null".
+  llvm::Constant *C =
+      CGM.EmitConstantExpr(Except->getFilterExpr(), getContext().IntTy, this);
+  if (C && C->isOneValue()) {
+    CatchScope->setCatchAllHandler(0, createBasicBlock("__except"));
+    return;
+  }
+
+  // In general, we have to emit an outlined filter function. Use the function
+  // in place of the RTTI typeinfo global that C++ EH uses.
+  llvm::Function *FilterFunc =
+      HelperCGF.GenerateSEHFilterFunction(*this, *Except);
+  llvm::Constant *OpaqueFunc =
+      llvm::ConstantExpr::getBitCast(FilterFunc, Int8PtrTy);
+  CatchScope->setHandler(0, OpaqueFunc, createBasicBlock("__except"));
+}
+
+void CodeGenFunction::ExitSEHTryStmt(const SEHTryStmt &S) {
+  // Just pop the cleanup if it's a __finally block.
+  if (S.getFinallyHandler()) {
+    PopCleanupBlock();
+    return;
+  }
+
+  // Otherwise, we must have an __except block.
+  const SEHExceptStmt *Except = S.getExceptHandler();
+  assert(Except && "__try must have __finally xor __except");
+  EHCatchScope &CatchScope = cast<EHCatchScope>(*EHStack.begin());
+
+  // Don't emit the __except block if the __try block lacked invokes.
+  // TODO: Model unwind edges from instructions, either with iload / istore or
+  // a try body function.
+  if (!CatchScope.hasEHBranches()) {
+    CatchScope.clearHandlerBlocks();
+    EHStack.popCatch();
+    return;
+  }
+
+  // The fall-through block.
+  llvm::BasicBlock *ContBB = createBasicBlock("__try.cont");
+
+  // We just emitted the body of the __try; jump to the continue block.
+  if (HaveInsertPoint())
+    Builder.CreateBr(ContBB);
+
+  // Check if our filter function returned true.
+  emitCatchDispatchBlock(*this, CatchScope);
+
+  // Grab the block before we pop the handler.
+  llvm::BasicBlock *ExceptBB = CatchScope.getHandler(0).Block;
+  EHStack.popCatch();
+
+  EmitBlockAfterUses(ExceptBB);
+
+  // Emit the __except body.
+  EmitStmt(Except->getBlock());
+
+  if (HaveInsertPoint())
+    Builder.CreateBr(ContBB);
+
+  EmitBlock(ContBB);
 }
 
 void CodeGenFunction::EmitSEHLeaveStmt(const SEHLeaveStmt &S) {
-  CGM.ErrorUnsupported(&S, "SEH __leave");
+  // If this code is reachable then emit a stop point (if generating
+  // debug info). We have to do this ourselves because we are on the
+  // "simple" statement path.
+  if (HaveInsertPoint())
+    EmitStopPoint(&S);
+
+  // This must be a __leave from a __finally block, which we warn on and is UB.
+  // Just emit unreachable.
+  if (!isSEHTryScope()) {
+    Builder.CreateUnreachable();
+    Builder.ClearInsertionPoint();
+    return;
+  }
+
+  EmitBranchThroughCleanup(*SEHTryEpilogueStack.back());
 }