[WinEH] Remove NewMSEH and enable its behavior by default

Testing has shown that it is at least as reliable as the old landingpad
pattern matching code.

llvm-svn: 249647

5 files changed, 44 insertions, 77 deletions

diff --git a/clang/lib/CodeGen/CGCleanup.cpp b/clang/lib/CodeGen/CGCleanup.cpp
index 31c870ff6f6..5796320894b 100644
--- a/clang/lib/CodeGen/CGCleanup.cpp
+++ b/clang/lib/CodeGen/CGCleanup.cpp
@@ -933,8 +933,7 @@ void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
     EmitBlock(EHEntry);
     llvm::CleanupPadInst *CPI = nullptr;
     llvm::BasicBlock *NextAction = getEHDispatchBlock(EHParent);
-    if (CGM.getCodeGenOpts().NewMSEH &&
-        EHPersonality::get(*this).isMSVCPersonality())
+    if (EHPersonality::get(*this).usesFuncletPads())
       CPI = Builder.CreateCleanupPad({});
 
     // We only actually emit the cleanup code if the cleanup is either
diff --git a/clang/lib/CodeGen/CGCleanup.h b/clang/lib/CodeGen/CGCleanup.h
index 51b33f43e90..5a0145eb0b8 100644
--- a/clang/lib/CodeGen/CGCleanup.h
+++ b/clang/lib/CodeGen/CGCleanup.h
@@ -633,6 +633,10 @@ struct EHPersonality {
   static const EHPersonality MSVC_C_specific_handler;
   static const EHPersonality MSVC_CxxFrameHandler3;
 
+  /// Does this personality use landingpads or the family of pad instructions
+  /// designed to form funclets?
+  bool usesFuncletPads() const { return isMSVCPersonality(); }
+
   bool isMSVCPersonality() const {
     return this == &MSVC_except_handler || this == &MSVC_C_specific_handler ||
            this == &MSVC_CxxFrameHandler3;
diff --git a/clang/lib/CodeGen/CGException.cpp b/clang/lib/CodeGen/CGException.cpp
index 2490098d67c..16f6e83647b 100644
--- a/clang/lib/CodeGen/CGException.cpp
+++ b/clang/lib/CodeGen/CGException.cpp
@@ -572,8 +572,7 @@ void CodeGenFunction::EnterCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
 
 llvm::BasicBlock *
 CodeGenFunction::getEHDispatchBlock(EHScopeStack::stable_iterator si) {
-  if (CGM.getCodeGenOpts().NewMSEH &&
-      EHPersonality::get(*this).isMSVCPersonality())
+  if (EHPersonality::get(*this).usesFuncletPads())
     return getMSVCDispatchBlock(si);
 
   // The dispatch block for the end of the scope chain is a block that
@@ -705,8 +704,8 @@ llvm::BasicBlock *CodeGenFunction::getInvokeDestImpl() {
   if (!CurFn->hasPersonalityFn())
     CurFn->setPersonalityFn(getOpaquePersonalityFn(CGM, Personality));
 
-  if (CGM.getCodeGenOpts().NewMSEH && Personality.isMSVCPersonality()) {
-    // We don't need separate landing pads in the MSVC model.
+  if (Personality.usesFuncletPads()) {
+    // We don't need separate landing pads in the funclet model.
     LP = getEHDispatchBlock(EHStack.getInnermostEHScope());
   } else {
     // Build the landing pad for this scope.
@@ -870,8 +869,8 @@ llvm::BasicBlock *CodeGenFunction::EmitLandingPad() {
   return lpad;
 }
 
-static llvm::BasicBlock *emitMSVCCatchDispatchBlock(CodeGenFunction &CGF,
-                                                    EHCatchScope &CatchScope) {
+static llvm::BasicBlock *emitCatchPadBlock(CodeGenFunction &CGF,
+                                           EHCatchScope &CatchScope) {
   llvm::BasicBlock *DispatchBlock = CatchScope.getCachedEHDispatchBlock();
   assert(DispatchBlock);
 
@@ -922,9 +921,8 @@ static llvm::BasicBlock *emitMSVCCatchDispatchBlock(CodeGenFunction &CGF,
 /// block holding the final catchendblock instruction is returned.
 static llvm::BasicBlock *emitCatchDispatchBlock(CodeGenFunction &CGF,
                                                 EHCatchScope &catchScope) {
-  if (CGF.CGM.getCodeGenOpts().NewMSEH &&
-      EHPersonality::get(CGF).isMSVCPersonality())
-    return emitMSVCCatchDispatchBlock(CGF, catchScope);
+  if (EHPersonality::get(CGF).usesFuncletPads())
+    return emitCatchPadBlock(CGF, catchScope);
 
   llvm::BasicBlock *dispatchBlock = catchScope.getCachedEHDispatchBlock();
   assert(dispatchBlock);
@@ -1337,8 +1335,7 @@ llvm::BasicBlock *CodeGenFunction::getTerminateHandler() {
   // end of the function by FinishFunction.
   TerminateHandler = createBasicBlock("terminate.handler");
   Builder.SetInsertPoint(TerminateHandler);
-  if (CGM.getCodeGenOpts().NewMSEH &&
-      EHPersonality::get(*this).isMSVCPersonality()) {
+  if (EHPersonality::get(*this).usesFuncletPads()) {
     Builder.CreateTerminatePad(/*UnwindBB=*/nullptr, CGM.getTerminateFn());
   } else {
     llvm::Value *Exn = nullptr;
@@ -1441,8 +1438,8 @@ struct PerformSEHFinally final : EHScopeStack::Cleanup {
         CGM.getTypes().arrangeFreeFunctionCall(Args, FPT,
                                                /*chainCall=*/false);
 
-    // If this is the normal cleanup or using the old EH IR, just emit the call.
-    if (!F.isForEHCleanup() || !CGM.getCodeGenOpts().NewMSEH) {
+    // If this is the normal cleanup, just emit the call.
+    if (!F.isForEHCleanup()) {
       CGF.EmitCall(FnInfo, OutlinedFinally, ReturnValueSlot(), Args);
       return;
     }
@@ -1888,31 +1885,22 @@ void CodeGenFunction::ExitSEHTryStmt(const SEHTryStmt &S) {
 
   EmitBlockAfterUses(ExceptBB);
 
-  if (CGM.getCodeGenOpts().NewMSEH) {
-    // __except blocks don't get outlined into funclets, so immediately do a
-    // catchret.
-    llvm::BasicBlock *CatchPadBB = ExceptBB->getSinglePredecessor();
-    assert(CatchPadBB && "only ExceptBB pred should be catchpad");
-    llvm::CatchPadInst *CPI =
-        cast<llvm::CatchPadInst>(CatchPadBB->getFirstNonPHI());
-    ExceptBB = createBasicBlock("__except");
-    Builder.CreateCatchRet(CPI, ExceptBB);
-    EmitBlock(ExceptBB);
-    // On Win64, the exception code is returned in EAX. Copy it into the slot.
-    if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
-      llvm::Function *SEHCodeIntrin =
-          CGM.getIntrinsic(llvm::Intrinsic::eh_exceptioncode);
-      llvm::Value *Code = Builder.CreateCall(SEHCodeIntrin, {CPI});
-      Builder.CreateStore(Code, SEHCodeSlotStack.back());
-    }
-  } else {
-    // On Win64, the exception pointer is the exception code. Copy it to the slot.
-    if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
-      llvm::Value *Code =
-          Builder.CreatePtrToInt(getExceptionFromSlot(), IntPtrTy);
-      Code = Builder.CreateTrunc(Code, Int32Ty);
-      Builder.CreateStore(Code, SEHCodeSlotStack.back());
-    }
+  // __except blocks don't get outlined into funclets, so immediately do a
+  // catchret.
+  llvm::BasicBlock *CatchPadBB = ExceptBB->getSinglePredecessor();
+  assert(CatchPadBB && "only ExceptBB pred should be catchpad");
+  llvm::CatchPadInst *CPI =
+      cast<llvm::CatchPadInst>(CatchPadBB->getFirstNonPHI());
+  ExceptBB = createBasicBlock("__except");
+  Builder.CreateCatchRet(CPI, ExceptBB);
+  EmitBlock(ExceptBB);
+
+  // On Win64, the exception code is returned in EAX. Copy it into the slot.
+  if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
+    llvm::Function *SEHCodeIntrin =
+        CGM.getIntrinsic(llvm::Intrinsic::eh_exceptioncode);
+    llvm::Value *Code = Builder.CreateCall(SEHCodeIntrin, {CPI});
+    Builder.CreateStore(Code, SEHCodeSlotStack.back());
   }
 
   // Emit the __except body.
diff --git a/clang/lib/CodeGen/MicrosoftCXXABI.cpp b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
index 504dc3fa09b..369d21f3988 100644
--- a/clang/lib/CodeGen/MicrosoftCXXABI.cpp
+++ b/clang/lib/CodeGen/MicrosoftCXXABI.cpp
@@ -879,20 +879,15 @@ void MicrosoftCXXABI::emitRethrow(CodeGenFunction &CGF, bool isNoReturn) {
 }
 
 namespace {
-struct CallEndCatchMSVC final : EHScopeStack::Cleanup {
+struct CatchRetScope final : EHScopeStack::Cleanup {
   llvm::CatchPadInst *CPI;
 
-  CallEndCatchMSVC(llvm::CatchPadInst *CPI) : CPI(CPI) {}
+  CatchRetScope(llvm::CatchPadInst *CPI) : CPI(CPI) {}
 
   void Emit(CodeGenFunction &CGF, Flags flags) override {
-    if (CGF.CGM.getCodeGenOpts().NewMSEH) {
-      llvm::BasicBlock *BB = CGF.createBasicBlock("catchret.dest");
-      CGF.Builder.CreateCatchRet(CPI, BB);
-      CGF.EmitBlock(BB);
-    } else {
-      CGF.EmitNounwindRuntimeCall(
-          CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_endcatch));
-    }
+    llvm::BasicBlock *BB = CGF.createBasicBlock("catchret.dest");
+    CGF.Builder.CreateCatchRet(CPI, BB);
+    CGF.EmitBlock(BB);
   }
 };
 }
@@ -902,39 +897,21 @@ void MicrosoftCXXABI::emitBeginCatch(CodeGenFunction &CGF,
   // In the MS ABI, the runtime handles the copy, and the catch handler is
   // responsible for destruction.
   VarDecl *CatchParam = S->getExceptionDecl();
-  llvm::Value *Exn = nullptr;
-  llvm::Function *BeginCatch = nullptr;
-  llvm::CatchPadInst *CPI = nullptr;
-  bool NewEH = CGF.CGM.getCodeGenOpts().NewMSEH;
-  if (!NewEH) {
-    Exn = CGF.getExceptionFromSlot();
-    BeginCatch = CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_begincatch);
-  } else {
-    llvm::BasicBlock *CatchPadBB =
-        CGF.Builder.GetInsertBlock()->getSinglePredecessor();
-    CPI = cast<llvm::CatchPadInst>(CatchPadBB->getFirstNonPHI());
-  }
+  llvm::BasicBlock *CatchPadBB =
+      CGF.Builder.GetInsertBlock()->getSinglePredecessor();
+  llvm::CatchPadInst *CPI =
+      cast<llvm::CatchPadInst>(CatchPadBB->getFirstNonPHI());
+
   // If this is a catch-all or the catch parameter is unnamed, we don't need to
   // emit an alloca to the object.
   if (!CatchParam || !CatchParam->getDeclName()) {
-    if (!NewEH) {
-      llvm::Value *Args[2] = {Exn, llvm::Constant::getNullValue(CGF.Int8PtrTy)};
-      CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
-    }
-    CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalCleanup, CPI);
+    CGF.EHStack.pushCleanup<CatchRetScope>(NormalCleanup, CPI);
     return;
   }
 
   CodeGenFunction::AutoVarEmission var = CGF.EmitAutoVarAlloca(*CatchParam);
-  if (!NewEH) {
-    Address ParamAddr =
-        CGF.Builder.CreateElementBitCast(var.getObjectAddress(CGF), CGF.Int8Ty);
-    llvm::Value *Args[2] = {Exn, ParamAddr.getPointer()};
-    CGF.EmitNounwindRuntimeCall(BeginCatch, Args);
-  } else {
-    CPI->setArgOperand(2, var.getObjectAddress(CGF).getPointer());
-  }
-  CGF.EHStack.pushCleanup<CallEndCatchMSVC>(NormalCleanup, CPI);
+  CPI->setArgOperand(2, var.getObjectAddress(CGF).getPointer());
+  CGF.EHStack.pushCleanup<CatchRetScope>(NormalCleanup, CPI);
   CGF.EmitAutoVarCleanups(var);
 }
 
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index a1afd80f699..8a7e879d07b 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -462,7 +462,6 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.DumpCoverageMapping = Args.hasArg(OPT_dump_coverage_mapping);
   Opts.AsmVerbose = Args.hasArg(OPT_masm_verbose);
   Opts.ObjCAutoRefCountExceptions = Args.hasArg(OPT_fobjc_arc_exceptions);
-  Opts.NewMSEH = Args.hasArg(OPT_fnew_ms_eh);
   Opts.CXAAtExit = !Args.hasArg(OPT_fno_use_cxa_atexit);
   Opts.CXXCtorDtorAliases = Args.hasArg(OPT_mconstructor_aliases);
   Opts.CodeModel = getCodeModel(Args, Diags);