Add the 'resume' instruction for the new EH rewrite.

This adds the 'resume' instruction class, IR parsing, and bitcode reading and
writing. The 'resume' instruction resumes propagation of an existing (in-flight)
exception whose unwinding was interrupted with a 'landingpad' instruction (to be
added later).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136589 91177308-0d34-0410-b5e6-96231b3b80d8

17 files changed, 95 insertions, 8 deletions

diff --git a/lib/AsmParser/LLLexer.cpp b/lib/AsmParser/LLLexer.cpp
index 95b40c9838..c3a5a4d0db 100644
--- a/lib/AsmParser/LLLexer.cpp
+++ b/lib/AsmParser/LLLexer.cpp
@@ -636,6 +636,7 @@ lltok::Kind LLLexer::LexIdentifier() {
   INSTKEYWORD(switch,      Switch);
   INSTKEYWORD(indirectbr,  IndirectBr);
   INSTKEYWORD(invoke,      Invoke);
+  INSTKEYWORD(resume,      Resume);
   INSTKEYWORD(unwind,      Unwind);
   INSTKEYWORD(unreachable, Unreachable);
 
diff --git a/lib/AsmParser/LLParser.cpp b/lib/AsmParser/LLParser.cpp
index 4727fac8ef..82fab917fe 100644
--- a/lib/AsmParser/LLParser.cpp
+++ b/lib/AsmParser/LLParser.cpp
@@ -2885,6 +2885,7 @@ int LLParser::ParseInstruction(Instruction *&Inst, BasicBlock *BB,
   case lltok::kw_switch:      return ParseSwitch(Inst, PFS);
   case lltok::kw_indirectbr:  return ParseIndirectBr(Inst, PFS);
   case lltok::kw_invoke:      return ParseInvoke(Inst, PFS);
+  case lltok::kw_resume:      return ParseResume(Inst, PFS);
   // Binary Operators.
   case lltok::kw_add:
   case lltok::kw_sub:
@@ -3253,7 +3254,18 @@ bool LLParser::ParseInvoke(Instruction *&Inst, PerFunctionState &PFS) {
   return false;
 }
 
+/// ParseResume
+///   ::= 'resume' TypeAndValue
+bool LLParser::ParseResume(Instruction *&Inst, PerFunctionState &PFS) {
+  Value *Exn; LocTy ExnLoc;
+  LocTy Loc = Lex.getLoc();
+  if (ParseTypeAndValue(Exn, ExnLoc, PFS))
+    return true;
 
+  ResumeInst *RI = ResumeInst::Create(Exn);
+  Inst = RI;
+  return false;
+}
 
 //===----------------------------------------------------------------------===//
 // Binary Operators.
diff --git a/lib/AsmParser/LLParser.h b/lib/AsmParser/LLParser.h
index 2a7210a311..df058edd76 100644
--- a/lib/AsmParser/LLParser.h
+++ b/lib/AsmParser/LLParser.h
@@ -347,6 +347,7 @@ namespace llvm {
     bool ParseSwitch(Instruction *&Inst, PerFunctionState &PFS);
     bool ParseIndirectBr(Instruction *&Inst, PerFunctionState &PFS);
     bool ParseInvoke(Instruction *&Inst, PerFunctionState &PFS);
+    bool ParseResume(Instruction *&Inst, PerFunctionState &PFS);
 
     bool ParseArithmetic(Instruction *&I, PerFunctionState &PFS, unsigned Opc,
                          unsigned OperandType);
diff --git a/lib/AsmParser/LLToken.h b/lib/AsmParser/LLToken.h
index 75b332b6be..3da85ad5d7 100644
--- a/lib/AsmParser/LLToken.h
+++ b/lib/AsmParser/LLToken.h
@@ -124,7 +124,7 @@ namespace lltok {
     kw_fptoui, kw_fptosi, kw_inttoptr, kw_ptrtoint, kw_bitcast,
     kw_select, kw_va_arg,
 
-    kw_ret, kw_br, kw_switch, kw_indirectbr, kw_invoke, kw_unwind,
+    kw_ret, kw_br, kw_switch, kw_indirectbr, kw_invoke, kw_unwind, kw_resume,
     kw_unreachable,
 
     kw_alloca, kw_load, kw_store, kw_fence, kw_cmpxchg, kw_atomicrmw,
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index b4f47ad670..b4e105055e 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -2508,6 +2508,14 @@ bool BitcodeReader::ParseFunctionBody(Function *F) {
       cast<InvokeInst>(I)->setAttributes(PAL);
       break;
     }
+    case bitc::FUNC_CODE_INST_RESUME: { // RESUME: [opval]
+      unsigned Idx = 0;
+      Value *Val = 0;
+      if (getValueTypePair(Record, Idx, NextValueNo, Val))
+        return Error("Invalid RESUME record");
+      I = ResumeInst::Create(Val);
+      break;
+    }
     case bitc::FUNC_CODE_INST_UNWIND: // UNWIND
       I = new UnwindInst(Context);
       InstructionList.push_back(I);
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index dd071d89a6..9954400e5e 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -1143,6 +1143,10 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
     }
     break;
   }
+  case Instruction::Resume:
+    Code = bitc::FUNC_CODE_INST_RESUME;
+    PushValueAndType(I.getOperand(0), InstID, Vals, VE);
+    break;
   case Instruction::Unwind:
     Code = bitc::FUNC_CODE_INST_UNWIND;
     break;
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 86d32c218b..449f87ebda 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -1810,6 +1810,10 @@ void SelectionDAGBuilder::visitInvoke(const InvokeInst &I) {
 void SelectionDAGBuilder::visitUnwind(const UnwindInst &I) {
 }
 
+void SelectionDAGBuilder::visitResume(const ResumeInst &RI) {
+  llvm_unreachable("SelectionDAGBuilder shouldn't visit resume instructions!");
+}
+
 /// handleSmallSwitchCaseRange - Emit a series of specific tests (suitable for
 /// small case ranges).
 bool SelectionDAGBuilder::handleSmallSwitchRange(CaseRec& CR,
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
index aae56ba06a..050b86fb60 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
@@ -467,6 +467,7 @@ public:
 private:
   // These all get lowered before this pass.
   void visitInvoke(const InvokeInst &I);
+  void visitResume(const ResumeInst &I);
   void visitUnwind(const UnwindInst &I);
 
   void visitBinary(const User &I, unsigned OpCode);
diff --git a/lib/CodeGen/ShadowStackGC.cpp b/lib/CodeGen/ShadowStackGC.cpp
index 9807c8cb27..daab89b8f2 100644
--- a/lib/CodeGen/ShadowStackGC.cpp
+++ b/lib/CodeGen/ShadowStackGC.cpp
@@ -113,9 +113,11 @@ namespace {
         while (StateBB != StateE) {
           BasicBlock *CurBB = StateBB++;
 
-          // Branches and invokes do not escape, only unwind and return do.
+          // Branches and invokes do not escape, only unwind, resume, and return
+          // do.
           TerminatorInst *TI = CurBB->getTerminator();
-          if (!isa<UnwindInst>(TI) && !isa<ReturnInst>(TI))
+          if (!isa<UnwindInst>(TI) && !isa<ReturnInst>(TI) &&
+              !isa<ResumeInst>(TI))
             continue;
 
           Builder.SetInsertPoint(TI->getParent(), TI);
diff --git a/lib/Target/CBackend/CBackend.cpp b/lib/Target/CBackend/CBackend.cpp
index 18a27d2dc3..5b9a0a297f 100644
--- a/lib/Target/CBackend/CBackend.cpp
+++ b/lib/Target/CBackend/CBackend.cpp
@@ -288,10 +288,12 @@ namespace {
     void visitInvokeInst(InvokeInst &I) {
       llvm_unreachable("Lowerinvoke pass didn't work!");
     }
-
     void visitUnwindInst(UnwindInst &I) {
       llvm_unreachable("Lowerinvoke pass didn't work!");
     }
+    void visitResumeInst(ResumeInst &I) {
+      llvm_unreachable("DwarfEHPrepare pass didn't work!");
+    }
     void visitUnreachableInst(UnreachableInst &I);
 
     void visitPHINode(PHINode &I);
diff --git a/lib/Target/CppBackend/CPPBackend.cpp b/lib/Target/CppBackend/CPPBackend.cpp
index 7f5f5e189e..108023da95 100644
--- a/lib/Target/CppBackend/CPPBackend.cpp
+++ b/lib/Target/CppBackend/CPPBackend.cpp
@@ -1064,6 +1064,11 @@ void CppWriter::printInstruction(const Instruction *I,
     }
     break;
   }
+  case Instruction::Resume: {
+    Out << "ResumeInst::Create(mod->getContext(), " << opNames[0]
+        << ", " << bbname << ");";
+    break;
+  }
   case Instruction::Invoke: {
     const InvokeInst* inv = cast<InvokeInst>(I);
     Out << "std::vector<Value*> " << iName << "_params;";
diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp
index 0283568f2c..771a50b49d 100644
--- a/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/lib/Transforms/IPO/GlobalOpt.cpp
@@ -2506,7 +2506,7 @@ static bool EvaluateFunction(Function *F, Constant *&RetVal,
         CallStack.pop_back();  // return from fn.
         return true;  // We succeeded at evaluating this ctor!
       } else {
-        // invoke, unwind, unreachable.
+        // invoke, unwind, resume, unreachable.
         return false;  // Cannot handle this terminator.
       }
 
diff --git a/lib/Transforms/InstCombine/InstCombineCalls.cpp b/lib/Transforms/InstCombine/InstCombineCalls.cpp
index c33dec1740..09edc41997 100644
--- a/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -732,9 +732,11 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
       }
     }
     
-    // If the stack restore is in a return/unwind block and if there are no
-    // allocas or calls between the restore and the return, nuke the restore.
-    if (!CannotRemove && (isa<ReturnInst>(TI) || isa<UnwindInst>(TI)))
+    // If the stack restore is in a return, resume, or unwind block and if there
+    // are no allocas or calls between the restore and the return, nuke the
+    // restore.
+    if (!CannotRemove && (isa<ReturnInst>(TI) || isa<ResumeInst>(TI) ||
+                          isa<UnwindInst>(TI)))
       return EraseInstFromFunction(CI);
     break;
   }
diff --git a/lib/Transforms/Scalar/SCCP.cpp b/lib/Transforms/Scalar/SCCP.cpp
index 749ba40a64..4e1c27446c 100644
--- a/lib/Transforms/Scalar/SCCP.cpp
+++ b/lib/Transforms/Scalar/SCCP.cpp
@@ -528,6 +528,7 @@ private:
     visitTerminatorInst(II);
   }
   void visitCallSite      (CallSite CS);
+  void visitResumeInst    (TerminatorInst &I) { /*returns void*/ }
   void visitUnwindInst    (TerminatorInst &I) { /*returns void*/ }
   void visitUnreachableInst(TerminatorInst &I) { /*returns void*/ }
   void visitFenceInst     (FenceInst &I) { /*returns void*/ }
diff --git a/lib/VMCore/Core.cpp b/lib/VMCore/Core.cpp
index 3c93736ce1..ce010c1b7d 100644
--- a/lib/VMCore/Core.cpp
+++ b/lib/VMCore/Core.cpp
@@ -1687,6 +1687,10 @@ LLVMValueRef LLVMBuildUnwind(LLVMBuilderRef B) {
   return wrap(unwrap(B)->CreateUnwind());
 }
 
+LLVMValueRef LLVMBuildResume(LLVMBuilderRef B, LLVMValueRef Exn) {
+  return wrap(unwrap(B)->CreateResume(unwrap(Exn)));
+}
+
 LLVMValueRef LLVMBuildUnreachable(LLVMBuilderRef B) {
   return wrap(unwrap(B)->CreateUnreachable());
 }
diff --git a/lib/VMCore/Instruction.cpp b/lib/VMCore/Instruction.cpp
index c4365fcca6..216bb35d4d 100644
--- a/lib/VMCore/Instruction.cpp
+++ b/lib/VMCore/Instruction.cpp
@@ -101,6 +101,7 @@ const char *Instruction::getOpcodeName(unsigned OpCode) {
   case Switch: return "switch";
   case IndirectBr: return "indirectbr";
   case Invoke: return "invoke";
+  case Resume: return "resume";
   case Unwind: return "unwind";
   case Unreachable: return "unreachable";
 
diff --git a/lib/VMCore/Instructions.cpp b/lib/VMCore/Instructions.cpp
index 75458babfb..c36102d706 100644
--- a/lib/VMCore/Instructions.cpp
+++ b/lib/VMCore/Instructions.cpp
@@ -574,6 +574,41 @@ BasicBlock *UnwindInst::getSuccessorV(unsigned idx) const {
 }
 
 //===----------------------------------------------------------------------===//
+//                        ResumeInst Implementation
+//===----------------------------------------------------------------------===//
+
+ResumeInst::ResumeInst(const ResumeInst &RI)
+  : TerminatorInst(Type::getVoidTy(RI.getContext()), Instruction::Resume,
+                   OperandTraits<ResumeInst>::op_begin(this), 1) {
+  Op<0>() = RI.Op<0>();
+}
+
+ResumeInst::ResumeInst(Value *Exn, Instruction *InsertBefore)
+  : TerminatorInst(Type::getVoidTy(Exn->getContext()), Instruction::Resume,
+                   OperandTraits<ResumeInst>::op_begin(this), 1, InsertBefore) {
+  Op<0>() = Exn;
+}
+
+ResumeInst::ResumeInst(Value *Exn, BasicBlock *InsertAtEnd)
+  : TerminatorInst(Type::getVoidTy(Exn->getContext()), Instruction::Resume,
+                   OperandTraits<ResumeInst>::op_begin(this), 1, InsertAtEnd) {
+  Op<0>() = Exn;
+}
+
+unsigned ResumeInst::getNumSuccessorsV() const {
+  return getNumSuccessors();
+}
+
+void ResumeInst::setSuccessorV(unsigned idx, BasicBlock *NewSucc) {
+  llvm_unreachable("ResumeInst has no successors!");
+}
+
+BasicBlock *ResumeInst::getSuccessorV(unsigned idx) const {
+  llvm_unreachable("ResumeInst has no successors!");
+  return 0;
+}
+
+//===----------------------------------------------------------------------===//
 //                      UnreachableInst Implementation
 //===----------------------------------------------------------------------===//
 
@@ -3254,6 +3289,10 @@ InvokeInst *InvokeInst::clone_impl() const {
   return new(getNumOperands()) InvokeInst(*this);
 }
 
+ResumeInst *ResumeInst::clone_impl() const {
+  return new(1) ResumeInst(*this);
+}
+
 UnwindInst *UnwindInst::clone_impl() const {
   LLVMContext &Context = getContext();
   return new UnwindInst(Context);