X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FSelectionDAG%2FSelectionDAGBuilder.h;h=a27f470df17c8a48e10f2c9c62413f79ec5bec0a;hb=fcc330abfef50ecb692d72e5c853b2668cfedcc2;hp=1f4a247f0dfdd040872b87574842d66e883fa44f;hpb=8963fecc86def73634dabf7545322287aa6ae9f8;p=oota-llvm.git diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h index 1f4a247f0df..a27f470df17 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h +++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h @@ -1,4 +1,4 @@ -//===-- SelectionDAGBuilder.h - Selection-DAG building --------------------===// +//===-- SelectionDAGBuilder.h - Selection-DAG building --------*- C++ -*---===// // // The LLVM Compiler Infrastructure // @@ -11,21 +11,24 @@ // //===----------------------------------------------------------------------===// -#ifndef SELECTIONDAGBUILDER_H -#define SELECTIONDAGBUILDER_H +#ifndef LLVM_LIB_CODEGEN_SELECTIONDAG_SELECTIONDAGBUILDER_H +#define LLVM_LIB_CODEGEN_SELECTIONDAG_SELECTIONDAGBUILDER_H +#include "StatepointLowering.h" #include "llvm/ADT/APInt.h" #include "llvm/ADT/DenseMap.h" #include "llvm/CodeGen/SelectionDAG.h" #include "llvm/CodeGen/SelectionDAGNodes.h" -#include "llvm/CodeGen/ValueTypes.h" -#include "llvm/Constants.h" -#include "llvm/Support/CallSite.h" +#include "llvm/IR/CallSite.h" +#include "llvm/IR/Statepoint.h" +#include "llvm/IR/Constants.h" #include "llvm/Support/ErrorHandling.h" +#include "llvm/Target/TargetLowering.h" #include namespace llvm { +class AddrSpaceCastInst; class AliasAnalysis; class AllocaInst; class BasicBlock; @@ -56,6 +59,7 @@ class MachineBasicBlock; class MachineInstr; class MachineRegisterInfo; class MDNode; +class MVT; class PHINode; class PtrToIntInst; class ReturnInst; @@ -80,11 +84,11 @@ class ZExtInst; /// implementation that is parameterized by a TargetLowering object. /// class SelectionDAGBuilder { - /// CurDebugLoc - current file + line number. Changes as we build the DAG. - DebugLoc CurDebugLoc; + /// CurInst - The current instruction being visited + const Instruction *CurInst; DenseMap NodeMap; - + /// UnusedArgNodeMap - Maps argument value for unused arguments. This is used /// to preserve debug information for incoming arguments. DenseMap UnusedArgNodeMap; @@ -95,7 +99,7 @@ class SelectionDAGBuilder { DebugLoc dl; unsigned SDNodeOrder; public: - DanglingDebugInfo() : DI(0), dl(DebugLoc()), SDNodeOrder(0) { } + DanglingDebugInfo() : DI(nullptr), dl(DebugLoc()), SDNodeOrder(0) { } DanglingDebugInfo(const DbgValueInst *di, DebugLoc DL, unsigned SDNO) : DI(di), dl(DL), SDNodeOrder(SDNO) { } const DbgValueInst* getDI() { return DI; } @@ -113,6 +117,10 @@ public: /// get simple disambiguation between loads without worrying about alias /// analysis. SmallVector PendingLoads; + + /// State used while lowering a statepoint sequence (gc_statepoint, + /// gc_relocate, and gc_result). See StatepointLowering.hpp/cpp for details. + StatepointLoweringState StatepointLowering; private: /// PendingExports - CopyToReg nodes that copy values to virtual registers @@ -129,19 +137,19 @@ private: /// Case - A struct to record the Value for a switch case, and the /// case's target basic block. struct Case { - const Constant *Low; - const Constant *High; + const ConstantInt *Low; + const ConstantInt *High; MachineBasicBlock* BB; uint32_t ExtraWeight; - Case() : Low(0), High(0), BB(0), ExtraWeight(0) { } - Case(const Constant *low, const Constant *high, MachineBasicBlock *bb, + Case() : Low(nullptr), High(nullptr), BB(nullptr), ExtraWeight(0) { } + Case(const ConstantInt *low, const ConstantInt *high, MachineBasicBlock *bb, uint32_t extraweight) : Low(low), High(high), BB(bb), ExtraWeight(extraweight) { } APInt size() const { - const APInt &rHigh = cast(High)->getValue(); - const APInt &rLow = cast(Low)->getValue(); + const APInt &rHigh = High->getValue(); + const APInt &rLow = Low->getValue(); return (rHigh - rLow + 1ULL); } }; @@ -165,7 +173,7 @@ private: /// CaseRec - A struct with ctor used in lowering switches to a binary tree /// of conditional branches. struct CaseRec { - CaseRec(MachineBasicBlock *bb, const Constant *lt, const Constant *ge, + CaseRec(MachineBasicBlock *bb, const ConstantInt *lt, const ConstantInt *ge, CaseRange r) : CaseBB(bb), LT(lt), GE(ge), Range(r) {} @@ -173,8 +181,8 @@ private: MachineBasicBlock *CaseBB; /// LT, GE - If nonzero, we know the current case value must be less-than or /// greater-than-or-equal-to these Constants. - const Constant *LT; - const Constant *GE; + const ConstantInt *LT; + const ConstantInt *GE; /// Range - A pair of iterators representing the range of case values to be /// processed at this point in the binary search tree. CaseRange Range; @@ -188,7 +196,9 @@ private: } }; - size_t Clusterify(CaseVector &Cases, const SwitchInst &SI); + /// Populate Cases with the cases in SI, clustering adjacent cases with the + /// same destination together. + void Clusterify(CaseVector &Cases, const SwitchInst *SI); /// CaseBlock - This structure is used to communicate between /// SelectionDAGBuilder and SDISel for the code generation of additional basic @@ -224,7 +234,7 @@ private: struct JumpTable { JumpTable(unsigned R, unsigned J, MachineBasicBlock *M, MachineBasicBlock *D): Reg(R), JTI(J), MBB(M), Default(D) {} - + /// Reg - the virtual register containing the index of the jump table entry //. to jump to. unsigned Reg; @@ -264,9 +274,9 @@ private: BitTestBlock(APInt F, APInt R, const Value* SV, unsigned Rg, MVT RgVT, bool E, MachineBasicBlock* P, MachineBasicBlock* D, - const BitTestInfo& C): + BitTestInfo C): First(F), Range(R), SValue(SV), Reg(Rg), RegVT(RgVT), Emitted(E), - Parent(P), Default(D), Cases(C) { } + Parent(P), Default(D), Cases(std::move(C)) { } APInt First; APInt Range; const Value *SValue; @@ -278,14 +288,217 @@ private: BitTestInfo Cases; }; -public: - // TLI - This is information that describes the available target features we - // need for lowering. This indicates when operations are unavailable, - // implemented with a libcall, etc. + /// A class which encapsulates all of the information needed to generate a + /// stack protector check and signals to isel via its state being initialized + /// that a stack protector needs to be generated. + /// + /// *NOTE* The following is a high level documentation of SelectionDAG Stack + /// Protector Generation. The reason that it is placed here is for a lack of + /// other good places to stick it. + /// + /// High Level Overview of SelectionDAG Stack Protector Generation: + /// + /// Previously, generation of stack protectors was done exclusively in the + /// pre-SelectionDAG Codegen LLVM IR Pass "Stack Protector". This necessitated + /// splitting basic blocks at the IR level to create the success/failure basic + /// blocks in the tail of the basic block in question. As a result of this, + /// calls that would have qualified for the sibling call optimization were no + /// longer eligible for optimization since said calls were no longer right in + /// the "tail position" (i.e. the immediate predecessor of a ReturnInst + /// instruction). + /// + /// Then it was noticed that since the sibling call optimization causes the + /// callee to reuse the caller's stack, if we could delay the generation of + /// the stack protector check until later in CodeGen after the sibling call + /// decision was made, we get both the tail call optimization and the stack + /// protector check! + /// + /// A few goals in solving this problem were: + /// + /// 1. Preserve the architecture independence of stack protector generation. + /// + /// 2. Preserve the normal IR level stack protector check for platforms like + /// OpenBSD for which we support platform-specific stack protector + /// generation. + /// + /// The main problem that guided the present solution is that one can not + /// solve this problem in an architecture independent manner at the IR level + /// only. This is because: + /// + /// 1. The decision on whether or not to perform a sibling call on certain + /// platforms (for instance i386) requires lower level information + /// related to available registers that can not be known at the IR level. + /// + /// 2. Even if the previous point were not true, the decision on whether to + /// perform a tail call is done in LowerCallTo in SelectionDAG which + /// occurs after the Stack Protector Pass. As a result, one would need to + /// put the relevant callinst into the stack protector check success + /// basic block (where the return inst is placed) and then move it back + /// later at SelectionDAG/MI time before the stack protector check if the + /// tail call optimization failed. The MI level option was nixed + /// immediately since it would require platform-specific pattern + /// matching. The SelectionDAG level option was nixed because + /// SelectionDAG only processes one IR level basic block at a time + /// implying one could not create a DAG Combine to move the callinst. + /// + /// To get around this problem a few things were realized: + /// + /// 1. While one can not handle multiple IR level basic blocks at the + /// SelectionDAG Level, one can generate multiple machine basic blocks + /// for one IR level basic block. This is how we handle bit tests and + /// switches. + /// + /// 2. At the MI level, tail calls are represented via a special return + /// MIInst called "tcreturn". Thus if we know the basic block in which we + /// wish to insert the stack protector check, we get the correct behavior + /// by always inserting the stack protector check right before the return + /// statement. This is a "magical transformation" since no matter where + /// the stack protector check intrinsic is, we always insert the stack + /// protector check code at the end of the BB. + /// + /// Given the aforementioned constraints, the following solution was devised: + /// + /// 1. On platforms that do not support SelectionDAG stack protector check + /// generation, allow for the normal IR level stack protector check + /// generation to continue. + /// + /// 2. On platforms that do support SelectionDAG stack protector check + /// generation: + /// + /// a. Use the IR level stack protector pass to decide if a stack + /// protector is required/which BB we insert the stack protector check + /// in by reusing the logic already therein. If we wish to generate a + /// stack protector check in a basic block, we place a special IR + /// intrinsic called llvm.stackprotectorcheck right before the BB's + /// returninst or if there is a callinst that could potentially be + /// sibling call optimized, before the call inst. + /// + /// b. Then when a BB with said intrinsic is processed, we codegen the BB + /// normally via SelectBasicBlock. In said process, when we visit the + /// stack protector check, we do not actually emit anything into the + /// BB. Instead, we just initialize the stack protector descriptor + /// class (which involves stashing information/creating the success + /// mbbb and the failure mbb if we have not created one for this + /// function yet) and export the guard variable that we are going to + /// compare. + /// + /// c. After we finish selecting the basic block, in FinishBasicBlock if + /// the StackProtectorDescriptor attached to the SelectionDAGBuilder is + /// initialized, we first find a splice point in the parent basic block + /// before the terminator and then splice the terminator of said basic + /// block into the success basic block. Then we code-gen a new tail for + /// the parent basic block consisting of the two loads, the comparison, + /// and finally two branches to the success/failure basic blocks. We + /// conclude by code-gening the failure basic block if we have not + /// code-gened it already (all stack protector checks we generate in + /// the same function, use the same failure basic block). + class StackProtectorDescriptor { + public: + StackProtectorDescriptor() : ParentMBB(nullptr), SuccessMBB(nullptr), + FailureMBB(nullptr), Guard(nullptr), + GuardReg(0) { } + + /// Returns true if all fields of the stack protector descriptor are + /// initialized implying that we should/are ready to emit a stack protector. + bool shouldEmitStackProtector() const { + return ParentMBB && SuccessMBB && FailureMBB && Guard; + } + + /// Initialize the stack protector descriptor structure for a new basic + /// block. + void initialize(const BasicBlock *BB, + MachineBasicBlock *MBB, + const CallInst &StackProtCheckCall) { + // Make sure we are not initialized yet. + assert(!shouldEmitStackProtector() && "Stack Protector Descriptor is " + "already initialized!"); + ParentMBB = MBB; + SuccessMBB = AddSuccessorMBB(BB, MBB, /* IsLikely */ true); + FailureMBB = AddSuccessorMBB(BB, MBB, /* IsLikely */ false, FailureMBB); + if (!Guard) + Guard = StackProtCheckCall.getArgOperand(0); + } + + /// Reset state that changes when we handle different basic blocks. + /// + /// This currently includes: + /// + /// 1. The specific basic block we are generating a + /// stack protector for (ParentMBB). + /// + /// 2. The successor machine basic block that will contain the tail of + /// parent mbb after we create the stack protector check (SuccessMBB). This + /// BB is visited only on stack protector check success. + void resetPerBBState() { + ParentMBB = nullptr; + SuccessMBB = nullptr; + } + + /// Reset state that only changes when we switch functions. + /// + /// This currently includes: + /// + /// 1. FailureMBB since we reuse the failure code path for all stack + /// protector checks created in an individual function. + /// + /// 2.The guard variable since the guard variable we are checking against is + /// always the same. + void resetPerFunctionState() { + FailureMBB = nullptr; + Guard = nullptr; + } + + MachineBasicBlock *getParentMBB() { return ParentMBB; } + MachineBasicBlock *getSuccessMBB() { return SuccessMBB; } + MachineBasicBlock *getFailureMBB() { return FailureMBB; } + const Value *getGuard() { return Guard; } + + unsigned getGuardReg() const { return GuardReg; } + void setGuardReg(unsigned R) { GuardReg = R; } + + private: + /// The basic block for which we are generating the stack protector. + /// + /// As a result of stack protector generation, we will splice the + /// terminators of this basic block into the successor mbb SuccessMBB and + /// replace it with a compare/branch to the successor mbbs + /// SuccessMBB/FailureMBB depending on whether or not the stack protector + /// was violated. + MachineBasicBlock *ParentMBB; + + /// A basic block visited on stack protector check success that contains the + /// terminators of ParentMBB. + MachineBasicBlock *SuccessMBB; + + /// This basic block visited on stack protector check failure that will + /// contain a call to __stack_chk_fail(). + MachineBasicBlock *FailureMBB; + + /// The guard variable which we will compare against the stored value in the + /// stack protector stack slot. + const Value *Guard; + + /// The virtual register holding the stack guard value. + unsigned GuardReg; + + /// Add a successor machine basic block to ParentMBB. If the successor mbb + /// has not been created yet (i.e. if SuccMBB = 0), then the machine basic + /// block will be created. Assign a large weight if IsLikely is true. + MachineBasicBlock *AddSuccessorMBB(const BasicBlock *BB, + MachineBasicBlock *ParentMBB, + bool IsLikely, + MachineBasicBlock *SuccMBB = nullptr); + }; + +private: const TargetMachine &TM; - const TargetLowering &TLI; +public: + /// Lowest valid SDNodeOrder. The special case 0 is reserved for scheduling + /// nodes without a corresponding SDNode. + static const unsigned LowestSDNodeOrder = 1; + SelectionDAG &DAG; - const DataLayout *TD; + const DataLayout *DL; AliasAnalysis *AA; const TargetLibraryInfo *LibInfo; @@ -298,6 +511,9 @@ public: /// BitTestCases - Vector of BitTestBlock structures used to communicate /// SwitchInst code generation information. std::vector BitTestCases; + /// A StackProtectorDescriptor structure used to communicate stack protector + /// information in between SelectBasicBlock and FinishBasicBlock. + StackProtectorDescriptor SPDescriptor; // Emit PHI-node-operand constants only once even if used by multiple // PHI nodes. @@ -308,9 +524,9 @@ public: FunctionLoweringInfo &FuncInfo; /// OptLevel - What optimization level we're generating code for. - /// + /// CodeGenOpt::Level OptLevel; - + /// GFI - Garbage collection metadata for the function. GCFunctionInfo *GFI; @@ -327,7 +543,7 @@ public: SelectionDAGBuilder(SelectionDAG &dag, FunctionLoweringInfo &funcinfo, CodeGenOpt::Level ol) - : SDNodeOrder(0), TM(dag.getTarget()), TLI(dag.getTargetLoweringInfo()), + : CurInst(nullptr), SDNodeOrder(LowestSDNodeOrder), TM(dag.getTarget()), DAG(dag), FuncInfo(funcinfo), OptLevel(ol), HasTailCall(false) { } @@ -364,21 +580,26 @@ public: /// SDValue getControlRoot(); - DebugLoc getCurDebugLoc() const { return CurDebugLoc; } + SDLoc getCurSDLoc() const { + return SDLoc(CurInst, SDNodeOrder); + } + + DebugLoc getCurDebugLoc() const { + return CurInst ? CurInst->getDebugLoc() : DebugLoc(); + } unsigned getSDNodeOrder() const { return SDNodeOrder; } void CopyValueToVirtualRegister(const Value *V, unsigned Reg); - /// AssignOrderingToNode - Assign an ordering to the node. The order is gotten - /// from how the code appeared in the source. The ordering is used by the - /// scheduler to effectively turn off scheduling. - void AssignOrderingToNode(const SDNode *Node); - void visit(const Instruction &I); void visit(unsigned Opcode, const User &I); + /// getCopyFromRegs - If there was virtual register allocated for the value V + /// emit CopyFromReg of the specified type Ty. Return empty SDValue() otherwise. + SDValue getCopyFromRegs(const Value *V, Type *Ty); + // resolveDanglingDebugInfo - if we saw an earlier dbg_value referring to V, // generate the debug data structures now that we've seen its definition. void resolveDanglingDebugInfo(const Value *V, SDValue Val); @@ -388,41 +609,66 @@ public: void setValue(const Value *V, SDValue NewN) { SDValue &N = NodeMap[V]; - assert(N.getNode() == 0 && "Already set a value for this node!"); + assert(!N.getNode() && "Already set a value for this node!"); N = NewN; } - + + void removeValue(const Value *V) { + // This is to support hack in lowerCallFromStatepoint + // Should be removed when hack is resolved + NodeMap.erase(V); + } + void setUnusedArgValue(const Value *V, SDValue NewN) { SDValue &N = UnusedArgNodeMap[V]; - assert(N.getNode() == 0 && "Already set a value for this node!"); + assert(!N.getNode() && "Already set a value for this node!"); N = NewN; } void FindMergedConditions(const Value *Cond, MachineBasicBlock *TBB, MachineBasicBlock *FBB, MachineBasicBlock *CurBB, - MachineBasicBlock *SwitchBB, unsigned Opc); + MachineBasicBlock *SwitchBB, unsigned Opc, + uint32_t TW, uint32_t FW); void EmitBranchForMergedCondition(const Value *Cond, MachineBasicBlock *TBB, MachineBasicBlock *FBB, MachineBasicBlock *CurBB, - MachineBasicBlock *SwitchBB); + MachineBasicBlock *SwitchBB, + uint32_t TW, uint32_t FW); bool ShouldEmitAsBranches(const std::vector &Cases); bool isExportableFromCurrentBlock(const Value *V, const BasicBlock *FromBB); void CopyToExportRegsIfNeeded(const Value *V); void ExportFromCurrentBlock(const Value *V); void LowerCallTo(ImmutableCallSite CS, SDValue Callee, bool IsTailCall, - MachineBasicBlock *LandingPad = NULL); + MachineBasicBlock *LandingPad = nullptr); + + std::pair lowerCallOperands( + ImmutableCallSite CS, + unsigned ArgIdx, + unsigned NumArgs, + SDValue Callee, + bool UseVoidTy = false, + MachineBasicBlock *LandingPad = nullptr, + bool IsPatchPoint = false); /// UpdateSplitBlock - When an MBB was split during scheduling, update the - /// references that ned to refer to the last resulting block. + /// references that need to refer to the last resulting block. void UpdateSplitBlock(MachineBasicBlock *First, MachineBasicBlock *Last); + // This function is responsible for the whole statepoint lowering process. + // It uniformly handles invoke and call statepoints. + void LowerStatepoint(ImmutableStatepoint Statepoint, + MachineBasicBlock *LandingPad = nullptr); private: + std::pair lowerInvokable( + TargetLowering::CallLoweringInfo &CLI, + MachineBasicBlock *LandingPad); + // Terminator instructions. void visitRet(const ReturnInst &I); void visitBr(const BranchInst &I); void visitSwitch(const SwitchInst &I); void visitIndirectBr(const IndirectBrInst &I); - void visitUnreachable(const UnreachableInst &I) { /* noop */ } + void visitUnreachable(const UnreachableInst &I); // Helpers for visitSwitch bool handleSmallSwitchRange(CaseRec& CR, @@ -438,8 +684,9 @@ private: bool handleBTSplitSwitchCase(CaseRec& CR, CaseRecVector& WorkList, const Value* SV, - MachineBasicBlock* Default, MachineBasicBlock *SwitchBB); + void splitSwitchCase(CaseRec &CR, CaseItr Pivot, CaseRecVector &WorkList, + const Value *SV, MachineBasicBlock *SwitchBB); bool handleBitTestsSwitchCase(CaseRec& CR, CaseRecVector& WorkList, const Value* SV, @@ -453,6 +700,9 @@ private: public: void visitSwitchCase(CaseBlock &CB, MachineBasicBlock *SwitchBB); + void visitSPDescriptorParent(StackProtectorDescriptor &SPD, + MachineBasicBlock *ParentBB); + void visitSPDescriptorFailure(StackProtectorDescriptor &SPD); void visitBitTestHeader(BitTestBlock &B, MachineBasicBlock *SwitchBB); void visitBitTestCase(BitTestBlock &BB, MachineBasicBlock* NextMBB, @@ -463,7 +713,9 @@ public: void visitJumpTable(JumpTable &JT); void visitJumpTableHeader(JumpTable &JT, JumpTableHeader &JTH, MachineBasicBlock *SwitchBB); - + unsigned visitLandingPadClauseBB(GlobalValue *ClauseGV, + MachineBasicBlock *LPadMBB); + private: // These all get lowered before this pass. void visitInvoke(const InvokeInst &I); @@ -504,6 +756,7 @@ private: void visitPtrToInt(const User &I); void visitIntToPtr(const User &I); void visitBitCast(const User &I); + void visitAddrSpaceCast(const User &I); void visitExtractElement(const User &I); void visitInsertElement(const User &I); @@ -519,13 +772,21 @@ private: void visitAlloca(const AllocaInst &I); void visitLoad(const LoadInst &I); void visitStore(const StoreInst &I); + void visitMaskedLoad(const CallInst &I); + void visitMaskedStore(const CallInst &I); void visitAtomicCmpXchg(const AtomicCmpXchgInst &I); void visitAtomicRMW(const AtomicRMWInst &I); void visitFence(const FenceInst &I); void visitPHI(const PHINode &I); void visitCall(const CallInst &I); bool visitMemCmpCall(const CallInst &I); + bool visitMemChrCall(const CallInst &I); + bool visitStrCpyCall(const CallInst &I, bool isStpcpy); + bool visitStrCmpCall(const CallInst &I); + bool visitStrLenCall(const CallInst &I); + bool visitStrNLenCall(const CallInst &I); bool visitUnaryFloatCall(const CallInst &I, unsigned Opcode); + bool visitBinaryFloatCall(const CallInst &I, unsigned Opcode); void visitAtomicLoad(const LoadInst &I); void visitAtomicStore(const StoreInst &I); @@ -537,6 +798,14 @@ private: void visitVAArg(const VAArgInst &I); void visitVAEnd(const CallInst &I); void visitVACopy(const CallInst &I); + void visitStackmap(const CallInst &I); + void visitPatchpoint(ImmutableCallSite CS, + MachineBasicBlock *LandingPad = nullptr); + + // These three are implemented in StatepointLowering.cpp + void visitStatepoint(const CallInst &I); + void visitGCRelocate(const CallInst &I); + void visitGCResult(const CallInst &I); void visitUserOp1(const Instruction &I) { llvm_unreachable("UserOp1 should not exist at instruction selection time!"); @@ -545,13 +814,25 @@ private: llvm_unreachable("UserOp2 should not exist at instruction selection time!"); } + void processIntegerCallValue(const Instruction &I, + SDValue Value, bool IsSigned); + void HandlePHINodesInSuccessorBlocks(const BasicBlock *LLVMBB); /// EmitFuncArgumentDbgValue - If V is an function argument then create - /// corresponding DBG_VALUE machine instruction for it now. At the end of + /// corresponding DBG_VALUE machine instruction for it now. At the end of /// instruction selection, they will be inserted to the entry BB. - bool EmitFuncArgumentDbgValue(const Value *V, MDNode *Variable, - int64_t Offset, const SDValue &N); + bool EmitFuncArgumentDbgValue(const Value *V, MDLocalVariable *Variable, + MDExpression *Expr, MDLocation *DL, + int64_t Offset, bool IsIndirect, + const SDValue &N); + + /// Return the next block after MBB, or nullptr if there is none. + MachineBasicBlock *NextBlock(MachineBasicBlock *MBB); + + /// Update the DAG and DAG builder with the relevant information after + /// a new root node has been created which could be a tail call. + void updateDAGForMaybeTailCall(SDValue MaybeTC); }; } // end namespace llvm