[WinEH] Require token linkage in EH pad/ret signatures

Summary:
WinEHPrepare is going to require that cleanuppad and catchpad produce values
of token type which are consumed by any cleanupret or catchret exiting the
pad.  This change updates the signatures of those operators to require/enforce
that the type produced by the pads is token type and that the rets have an
appropriate argument.

The catchpad argument of a `CatchReturnInst` must be a `CatchPadInst` (and
similarly for `CleanupReturnInst`/`CleanupPadInst`).  To accommodate that
restriction, this change adds a notion of an operator constraint to both
LLParser and BitcodeReader, allowing appropriate sentinels to be constructed
for forward references and appropriate error messages to be emitted for
illegal inputs.

Also add a verifier rule (noted in LangRef) that a catchpad with a catchpad
predecessor must have no other predecessors; this ensures that WinEHPrepare
will see the expected linear relationship between sibling catches on the
same try.

Lastly, remove some superfluous/vestigial casts from instruction operand
setters operating on BasicBlocks.

Reviewers: rnk, majnemer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D12108

llvm-svn: 245797

1 files changed, 42 insertions, 60 deletions

diff --git a/llvm/lib/IR/Instructions.cpp b/llvm/lib/IR/Instructions.cpp
index 46c799ece2c..e79fa415ffb 100644
--- a/llvm/lib/IR/Instructions.cpp
+++ b/llvm/lib/IR/Instructions.cpp
@@ -684,51 +684,39 @@ CleanupReturnInst::CleanupReturnInst(const CleanupReturnInst &CRI)
                      CRI.getNumOperands()) {
   SubclassOptionalData = CRI.SubclassOptionalData;
   setInstructionSubclassData(CRI.getSubclassDataFromInstruction());
-  if (Value *RetVal = CRI.getReturnValue())
-    setReturnValue(RetVal);
-  if (BasicBlock *UnwindDest = CRI.getUnwindDest())
-    setUnwindDest(UnwindDest);
+  Op<-1>() = CRI.Op<-1>();
+  if (CRI.hasUnwindDest())
+    Op<-2>() = CRI.Op<-2>();
 }
 
-void CleanupReturnInst::init(Value *RetVal, BasicBlock *UnwindBB) {
+void CleanupReturnInst::init(CleanupPadInst *CleanupPad, BasicBlock *UnwindBB) {
   SubclassOptionalData = 0;
   if (UnwindBB)
     setInstructionSubclassData(getSubclassDataFromInstruction() | 1);
-  if (RetVal)
-    setInstructionSubclassData(getSubclassDataFromInstruction() | 2);
 
+  Op<-1>() = CleanupPad;
   if (UnwindBB)
-    setUnwindDest(UnwindBB);
-  if (RetVal)
-    setReturnValue(RetVal);
+    Op<-2>() = UnwindBB;
 }
 
-CleanupReturnInst::CleanupReturnInst(LLVMContext &C, Value *RetVal,
+CleanupReturnInst::CleanupReturnInst(CleanupPadInst *CleanupPad,
                                      BasicBlock *UnwindBB, unsigned Values,
                                      Instruction *InsertBefore)
-    : TerminatorInst(Type::getVoidTy(C), Instruction::CleanupRet,
+    : TerminatorInst(Type::getVoidTy(CleanupPad->getContext()),
+                     Instruction::CleanupRet,
                      OperandTraits<CleanupReturnInst>::op_end(this) - Values,
                      Values, InsertBefore) {
-  init(RetVal, UnwindBB);
+  init(CleanupPad, UnwindBB);
 }
 
-CleanupReturnInst::CleanupReturnInst(LLVMContext &C, Value *RetVal,
+CleanupReturnInst::CleanupReturnInst(CleanupPadInst *CleanupPad,
                                      BasicBlock *UnwindBB, unsigned Values,
                                      BasicBlock *InsertAtEnd)
-    : TerminatorInst(Type::getVoidTy(C), Instruction::CleanupRet,
+    : TerminatorInst(Type::getVoidTy(CleanupPad->getContext()),
+                     Instruction::CleanupRet,
                      OperandTraits<CleanupReturnInst>::op_end(this) - Values,
                      Values, InsertAtEnd) {
-  init(RetVal, UnwindBB);
-}
-
-BasicBlock *CleanupReturnInst::getUnwindDest() const {
-  if (hasUnwindDest())
-    return cast<BasicBlock>(getOperand(getUnwindLabelOpIdx()));
-  return nullptr;
-}
-void CleanupReturnInst::setUnwindDest(BasicBlock *NewDest) {
-  assert(NewDest);
-  setOperand(getUnwindLabelOpIdx(), NewDest);
+  init(CleanupPad, UnwindBB);
 }
 
 BasicBlock *CleanupReturnInst::getSuccessorV(unsigned Idx) const {
@@ -797,38 +785,32 @@ void CatchEndPadInst::setSuccessorV(unsigned Idx, BasicBlock *B) {
 //===----------------------------------------------------------------------===//
 //                        CatchReturnInst Implementation
 //===----------------------------------------------------------------------===//
-void CatchReturnInst::init(BasicBlock *BB, Value *RetVal) {
-  Op<-1>() = BB;
-  if (RetVal)
-    Op<-2>() = RetVal;
+void CatchReturnInst::init(CatchPadInst *CatchPad, BasicBlock *BB) {
+  Op<0>() = CatchPad;
+  Op<1>() = BB;
 }
 
 CatchReturnInst::CatchReturnInst(const CatchReturnInst &CRI)
     : TerminatorInst(Type::getVoidTy(CRI.getContext()), Instruction::CatchRet,
-                     OperandTraits<CatchReturnInst>::op_end(this) -
-                         CRI.getNumOperands(),
-                     CRI.getNumOperands()) {
-  Op<-1>() = CRI.Op<-1>();
-  if (CRI.getNumOperands() != 1) {
-    assert(CRI.getNumOperands() == 2);
-    Op<-2>() = CRI.Op<-2>();
-  }
+                     OperandTraits<CatchReturnInst>::op_begin(this), 2) {
+  Op<0>() = CRI.Op<0>();
+  Op<1>() = CRI.Op<1>();
 }
 
-CatchReturnInst::CatchReturnInst(BasicBlock *BB, Value *RetVal, unsigned Values,
+CatchReturnInst::CatchReturnInst(CatchPadInst *CatchPad, BasicBlock *BB,
                                  Instruction *InsertBefore)
     : TerminatorInst(Type::getVoidTy(BB->getContext()), Instruction::CatchRet,
-                     OperandTraits<CatchReturnInst>::op_end(this) - Values,
-                     Values, InsertBefore) {
-  init(BB, RetVal);
+                     OperandTraits<CatchReturnInst>::op_begin(this), 2,
+                     InsertBefore) {
+  init(CatchPad, BB);
 }
 
-CatchReturnInst::CatchReturnInst(BasicBlock *BB, Value *RetVal, unsigned Values,
+CatchReturnInst::CatchReturnInst(CatchPadInst *CatchPad, BasicBlock *BB,
                                  BasicBlock *InsertAtEnd)
     : TerminatorInst(Type::getVoidTy(BB->getContext()), Instruction::CatchRet,
-                     OperandTraits<CatchReturnInst>::op_end(this) - Values,
-                     Values, InsertAtEnd) {
-  init(BB, RetVal);
+                     OperandTraits<CatchReturnInst>::op_begin(this), 2,
+                     InsertAtEnd) {
+  init(CatchPad, BB);
 }
 
 BasicBlock *CatchReturnInst::getSuccessorV(unsigned Idx) const {
@@ -863,21 +845,21 @@ CatchPadInst::CatchPadInst(const CatchPadInst &CPI)
   std::copy(CPI.op_begin(), CPI.op_end(), op_begin());
 }
 
-CatchPadInst::CatchPadInst(Type *RetTy, BasicBlock *IfNormal,
-                           BasicBlock *IfException, ArrayRef<Value *> Args,
-                           unsigned Values, const Twine &NameStr,
-                           Instruction *InsertBefore)
-    : TerminatorInst(RetTy, Instruction::CatchPad,
+CatchPadInst::CatchPadInst(BasicBlock *IfNormal, BasicBlock *IfException,
+                           ArrayRef<Value *> Args, unsigned Values,
+                           const Twine &NameStr, Instruction *InsertBefore)
+    : TerminatorInst(Type::getTokenTy(IfNormal->getContext()),
+                     Instruction::CatchPad,
                      OperandTraits<CatchPadInst>::op_end(this) - Values, Values,
                      InsertBefore) {
   init(IfNormal, IfException, Args, NameStr);
 }
 
-CatchPadInst::CatchPadInst(Type *RetTy, BasicBlock *IfNormal,
-                           BasicBlock *IfException, ArrayRef<Value *> Args,
-                           unsigned Values, const Twine &NameStr,
-                           BasicBlock *InsertAtEnd)
-    : TerminatorInst(RetTy, Instruction::CatchPad,
+CatchPadInst::CatchPadInst(BasicBlock *IfNormal, BasicBlock *IfException,
+                           ArrayRef<Value *> Args, unsigned Values,
+                           const Twine &NameStr, BasicBlock *InsertAtEnd)
+    : TerminatorInst(Type::getTokenTy(IfNormal->getContext()),
+                     Instruction::CatchPad,
                      OperandTraits<CatchPadInst>::op_end(this) - Values, Values,
                      InsertAtEnd) {
   init(IfNormal, IfException, Args, NameStr);
@@ -962,17 +944,17 @@ CleanupPadInst::CleanupPadInst(const CleanupPadInst &CPI)
   std::copy(CPI.op_begin(), CPI.op_end(), op_begin());
 }
 
-CleanupPadInst::CleanupPadInst(Type *RetTy, ArrayRef<Value *> Args,
+CleanupPadInst::CleanupPadInst(LLVMContext &C, ArrayRef<Value *> Args,
                                const Twine &NameStr, Instruction *InsertBefore)
-    : Instruction(RetTy, Instruction::CleanupPad,
+    : Instruction(Type::getTokenTy(C), Instruction::CleanupPad,
                   OperandTraits<CleanupPadInst>::op_end(this) - Args.size(),
                   Args.size(), InsertBefore) {
   init(Args, NameStr);
 }
 
-CleanupPadInst::CleanupPadInst(Type *RetTy, ArrayRef<Value *> Args,
+CleanupPadInst::CleanupPadInst(LLVMContext &C, ArrayRef<Value *> Args,
                                const Twine &NameStr, BasicBlock *InsertAtEnd)
-    : Instruction(RetTy, Instruction::CleanupPad,
+    : Instruction(Type::getTokenTy(C), Instruction::CleanupPad,
                   OperandTraits<CleanupPadInst>::op_end(this) - Args.size(),
                   Args.size(), InsertAtEnd) {
   init(Args, NameStr);