| //===-- SelectionDAGBuilder.h - Selection-DAG building --------*- C++ -*---===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This implements routines for translating from LLVM IR into SelectionDAG IR. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #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/Analysis/AliasAnalysis.h" |
| #include "llvm/CodeGen/Analysis.h" |
| #include "llvm/CodeGen/SelectionDAG.h" |
| #include "llvm/CodeGen/SelectionDAGNodes.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 <vector> |
| |
| namespace llvm { |
| |
| class AddrSpaceCastInst; |
| class AllocaInst; |
| class BasicBlock; |
| class BitCastInst; |
| class BranchInst; |
| class CallInst; |
| class DbgValueInst; |
| class ExtractElementInst; |
| class ExtractValueInst; |
| class FCmpInst; |
| class FPExtInst; |
| class FPToSIInst; |
| class FPToUIInst; |
| class FPTruncInst; |
| class Function; |
| class FunctionLoweringInfo; |
| class GetElementPtrInst; |
| class GCFunctionInfo; |
| class ICmpInst; |
| class IntToPtrInst; |
| class IndirectBrInst; |
| class InvokeInst; |
| class InsertElementInst; |
| class InsertValueInst; |
| class Instruction; |
| class LoadInst; |
| class MachineBasicBlock; |
| class MachineInstr; |
| class MachineRegisterInfo; |
| class MDNode; |
| class MVT; |
| class PHINode; |
| class PtrToIntInst; |
| class ReturnInst; |
| class SDDbgValue; |
| class SExtInst; |
| class SelectInst; |
| class ShuffleVectorInst; |
| class SIToFPInst; |
| class StoreInst; |
| class SwitchInst; |
| class DataLayout; |
| class TargetLibraryInfo; |
| class TargetLowering; |
| class TruncInst; |
| class UIToFPInst; |
| class UnreachableInst; |
| class VAArgInst; |
| class ZExtInst; |
| |
| //===----------------------------------------------------------------------===// |
| /// SelectionDAGBuilder - This is the common target-independent lowering |
| /// implementation that is parameterized by a TargetLowering object. |
| /// |
| class SelectionDAGBuilder { |
| /// CurInst - The current instruction being visited |
| const Instruction *CurInst; |
| |
| DenseMap<const Value*, SDValue> NodeMap; |
| |
| /// UnusedArgNodeMap - Maps argument value for unused arguments. This is used |
| /// to preserve debug information for incoming arguments. |
| DenseMap<const Value*, SDValue> UnusedArgNodeMap; |
| |
| /// DanglingDebugInfo - Helper type for DanglingDebugInfoMap. |
| class DanglingDebugInfo { |
| const DbgValueInst* DI; |
| DebugLoc dl; |
| unsigned SDNodeOrder; |
| public: |
| 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; } |
| DebugLoc getdl() { return dl; } |
| unsigned getSDNodeOrder() { return SDNodeOrder; } |
| }; |
| |
| /// DanglingDebugInfoMap - Keeps track of dbg_values for which we have not |
| /// yet seen the referent. We defer handling these until we do see it. |
| DenseMap<const Value*, DanglingDebugInfo> DanglingDebugInfoMap; |
| |
| public: |
| /// PendingLoads - Loads are not emitted to the program immediately. We bunch |
| /// them up and then emit token factor nodes when possible. This allows us to |
| /// get simple disambiguation between loads without worrying about alias |
| /// analysis. |
| SmallVector<SDValue, 8> 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 |
| /// for export to other blocks need to be emitted before any terminator |
| /// instruction, but they have no other ordering requirements. We bunch them |
| /// up and the emit a single tokenfactor for them just before terminator |
| /// instructions. |
| SmallVector<SDValue, 8> PendingExports; |
| |
| /// SDNodeOrder - A unique monotonically increasing number used to order the |
| /// SDNodes we create. |
| unsigned SDNodeOrder; |
| |
| enum CaseClusterKind { |
| /// A cluster of adjacent case labels with the same destination, or just one |
| /// case. |
| CC_Range, |
| /// A cluster of cases suitable for jump table lowering. |
| CC_JumpTable, |
| /// A cluster of cases suitable for bit test lowering. |
| CC_BitTests |
| }; |
| |
| /// A cluster of case labels. |
| struct CaseCluster { |
| CaseClusterKind Kind; |
| const ConstantInt *Low, *High; |
| union { |
| MachineBasicBlock *MBB; |
| unsigned JTCasesIndex; |
| unsigned BTCasesIndex; |
| }; |
| BranchProbability Prob; |
| |
| static CaseCluster range(const ConstantInt *Low, const ConstantInt *High, |
| MachineBasicBlock *MBB, BranchProbability Prob) { |
| CaseCluster C; |
| C.Kind = CC_Range; |
| C.Low = Low; |
| C.High = High; |
| C.MBB = MBB; |
| C.Prob = Prob; |
| return C; |
| } |
| |
| static CaseCluster jumpTable(const ConstantInt *Low, |
| const ConstantInt *High, unsigned JTCasesIndex, |
| BranchProbability Prob) { |
| CaseCluster C; |
| C.Kind = CC_JumpTable; |
| C.Low = Low; |
| C.High = High; |
| C.JTCasesIndex = JTCasesIndex; |
| C.Prob = Prob; |
| return C; |
| } |
| |
| static CaseCluster bitTests(const ConstantInt *Low, const ConstantInt *High, |
| unsigned BTCasesIndex, BranchProbability Prob) { |
| CaseCluster C; |
| C.Kind = CC_BitTests; |
| C.Low = Low; |
| C.High = High; |
| C.BTCasesIndex = BTCasesIndex; |
| C.Prob = Prob; |
| return C; |
| } |
| }; |
| |
| typedef std::vector<CaseCluster> CaseClusterVector; |
| typedef CaseClusterVector::iterator CaseClusterIt; |
| |
| struct CaseBits { |
| uint64_t Mask; |
| MachineBasicBlock* BB; |
| unsigned Bits; |
| BranchProbability ExtraProb; |
| |
| CaseBits(uint64_t mask, MachineBasicBlock* bb, unsigned bits, |
| BranchProbability Prob): |
| Mask(mask), BB(bb), Bits(bits), ExtraProb(Prob) { } |
| |
| CaseBits() : Mask(0), BB(nullptr), Bits(0) {} |
| }; |
| |
| typedef std::vector<CaseBits> CaseBitsVector; |
| |
| /// Sort Clusters and merge adjacent cases. |
| void sortAndRangeify(CaseClusterVector &Clusters); |
| |
| /// CaseBlock - This structure is used to communicate between |
| /// SelectionDAGBuilder and SDISel for the code generation of additional basic |
| /// blocks needed by multi-case switch statements. |
| struct CaseBlock { |
| CaseBlock(ISD::CondCode cc, const Value *cmplhs, const Value *cmprhs, |
| const Value *cmpmiddle, MachineBasicBlock *truebb, |
| MachineBasicBlock *falsebb, MachineBasicBlock *me, |
| BranchProbability trueprob = BranchProbability::getUnknown(), |
| BranchProbability falseprob = BranchProbability::getUnknown()) |
| : CC(cc), CmpLHS(cmplhs), CmpMHS(cmpmiddle), CmpRHS(cmprhs), |
| TrueBB(truebb), FalseBB(falsebb), ThisBB(me), TrueProb(trueprob), |
| FalseProb(falseprob) {} |
| |
| // CC - the condition code to use for the case block's setcc node |
| ISD::CondCode CC; |
| |
| // CmpLHS/CmpRHS/CmpMHS - The LHS/MHS/RHS of the comparison to emit. |
| // Emit by default LHS op RHS. MHS is used for range comparisons: |
| // If MHS is not null: (LHS <= MHS) and (MHS <= RHS). |
| const Value *CmpLHS, *CmpMHS, *CmpRHS; |
| |
| // TrueBB/FalseBB - the block to branch to if the setcc is true/false. |
| MachineBasicBlock *TrueBB, *FalseBB; |
| |
| // ThisBB - the block into which to emit the code for the setcc and branches |
| MachineBasicBlock *ThisBB; |
| |
| // TrueProb/FalseProb - branch weights. |
| BranchProbability TrueProb, FalseProb; |
| }; |
| |
| 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; |
| /// JTI - the JumpTableIndex for this jump table in the function. |
| unsigned JTI; |
| /// MBB - the MBB into which to emit the code for the indirect jump. |
| MachineBasicBlock *MBB; |
| /// Default - the MBB of the default bb, which is a successor of the range |
| /// check MBB. This is when updating PHI nodes in successors. |
| MachineBasicBlock *Default; |
| }; |
| struct JumpTableHeader { |
| JumpTableHeader(APInt F, APInt L, const Value *SV, MachineBasicBlock *H, |
| bool E = false): |
| First(F), Last(L), SValue(SV), HeaderBB(H), Emitted(E) {} |
| APInt First; |
| APInt Last; |
| const Value *SValue; |
| MachineBasicBlock *HeaderBB; |
| bool Emitted; |
| }; |
| typedef std::pair<JumpTableHeader, JumpTable> JumpTableBlock; |
| |
| struct BitTestCase { |
| BitTestCase(uint64_t M, MachineBasicBlock* T, MachineBasicBlock* Tr, |
| BranchProbability Prob): |
| Mask(M), ThisBB(T), TargetBB(Tr), ExtraProb(Prob) { } |
| uint64_t Mask; |
| MachineBasicBlock *ThisBB; |
| MachineBasicBlock *TargetBB; |
| BranchProbability ExtraProb; |
| }; |
| |
| typedef SmallVector<BitTestCase, 3> BitTestInfo; |
| |
| struct BitTestBlock { |
| BitTestBlock(APInt F, APInt R, const Value *SV, unsigned Rg, MVT RgVT, |
| bool E, bool CR, MachineBasicBlock *P, MachineBasicBlock *D, |
| BitTestInfo C, BranchProbability Pr) |
| : First(F), Range(R), SValue(SV), Reg(Rg), RegVT(RgVT), Emitted(E), |
| ContiguousRange(CR), Parent(P), Default(D), Cases(std::move(C)), |
| Prob(Pr) {} |
| APInt First; |
| APInt Range; |
| const Value *SValue; |
| unsigned Reg; |
| MVT RegVT; |
| bool Emitted; |
| bool ContiguousRange; |
| MachineBasicBlock *Parent; |
| MachineBasicBlock *Default; |
| BitTestInfo Cases; |
| BranchProbability Prob; |
| BranchProbability DefaultProb; |
| }; |
| |
| /// Minimum jump table density, in percent. |
| enum { MinJumpTableDensity = 40 }; |
| |
| /// Check whether a range of clusters is dense enough for a jump table. |
| bool isDense(const CaseClusterVector &Clusters, unsigned *TotalCases, |
| unsigned First, unsigned Last); |
| |
| /// Build a jump table cluster from Clusters[First..Last]. Returns false if it |
| /// decides it's not a good idea. |
| bool buildJumpTable(CaseClusterVector &Clusters, unsigned First, |
| unsigned Last, const SwitchInst *SI, |
| MachineBasicBlock *DefaultMBB, CaseCluster &JTCluster); |
| |
| /// Find clusters of cases suitable for jump table lowering. |
| void findJumpTables(CaseClusterVector &Clusters, const SwitchInst *SI, |
| MachineBasicBlock *DefaultMBB); |
| |
| /// Check whether the range [Low,High] fits in a machine word. |
| bool rangeFitsInWord(const APInt &Low, const APInt &High); |
| |
| /// Check whether these clusters are suitable for lowering with bit tests based |
| /// on the number of destinations, comparison metric, and range. |
| bool isSuitableForBitTests(unsigned NumDests, unsigned NumCmps, |
| const APInt &Low, const APInt &High); |
| |
| /// Build a bit test cluster from Clusters[First..Last]. Returns false if it |
| /// decides it's not a good idea. |
| bool buildBitTests(CaseClusterVector &Clusters, unsigned First, unsigned Last, |
| const SwitchInst *SI, CaseCluster &BTCluster); |
| |
| /// Find clusters of cases suitable for bit test lowering. |
| void findBitTestClusters(CaseClusterVector &Clusters, const SwitchInst *SI); |
| |
| struct SwitchWorkListItem { |
| MachineBasicBlock *MBB; |
| CaseClusterIt FirstCluster; |
| CaseClusterIt LastCluster; |
| const ConstantInt *GE; |
| const ConstantInt *LT; |
| BranchProbability DefaultProb; |
| }; |
| typedef SmallVector<SwitchWorkListItem, 4> SwitchWorkList; |
| |
| /// Determine the rank by weight of CC in [First,Last]. If CC has more weight |
| /// than each cluster in the range, its rank is 0. |
| static unsigned caseClusterRank(const CaseCluster &CC, CaseClusterIt First, |
| CaseClusterIt Last); |
| |
| /// Emit comparison and split W into two subtrees. |
| void splitWorkItem(SwitchWorkList &WorkList, const SwitchWorkListItem &W, |
| Value *Cond, MachineBasicBlock *SwitchMBB); |
| |
| /// Lower W. |
| void lowerWorkItem(SwitchWorkListItem W, Value *Cond, |
| MachineBasicBlock *SwitchMBB, |
| MachineBasicBlock *DefaultMBB); |
| |
| |
| /// 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; |
| GuardReg = 0; |
| } |
| |
| 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; |
| 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 *DL; |
| AliasAnalysis *AA; |
| const TargetLibraryInfo *LibInfo; |
| |
| /// SwitchCases - Vector of CaseBlock structures used to communicate |
| /// SwitchInst code generation information. |
| std::vector<CaseBlock> SwitchCases; |
| /// JTCases - Vector of JumpTable structures used to communicate |
| /// SwitchInst code generation information. |
| std::vector<JumpTableBlock> JTCases; |
| /// BitTestCases - Vector of BitTestBlock structures used to communicate |
| /// SwitchInst code generation information. |
| std::vector<BitTestBlock> 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. |
| DenseMap<const Constant *, unsigned> ConstantsOut; |
| |
| /// FuncInfo - Information about the function as a whole. |
| /// |
| FunctionLoweringInfo &FuncInfo; |
| |
| /// GFI - Garbage collection metadata for the function. |
| GCFunctionInfo *GFI; |
| |
| /// LPadToCallSiteMap - Map a landing pad to the call site indexes. |
| DenseMap<MachineBasicBlock*, SmallVector<unsigned, 4> > LPadToCallSiteMap; |
| |
| /// HasTailCall - This is set to true if a call in the current |
| /// block has been translated as a tail call. In this case, |
| /// no subsequent DAG nodes should be created. |
| /// |
| bool HasTailCall; |
| |
| LLVMContext *Context; |
| |
| SelectionDAGBuilder(SelectionDAG &dag, FunctionLoweringInfo &funcinfo, |
| CodeGenOpt::Level ol) |
| : CurInst(nullptr), SDNodeOrder(LowestSDNodeOrder), TM(dag.getTarget()), |
| DAG(dag), FuncInfo(funcinfo), |
| HasTailCall(false) { |
| } |
| |
| void init(GCFunctionInfo *gfi, AliasAnalysis &aa, |
| const TargetLibraryInfo *li); |
| |
| /// clear - Clear out the current SelectionDAG and the associated |
| /// state and prepare this SelectionDAGBuilder object to be used |
| /// for a new block. This doesn't clear out information about |
| /// additional blocks that are needed to complete switch lowering |
| /// or PHI node updating; that information is cleared out as it is |
| /// consumed. |
| void clear(); |
| |
| /// clearDanglingDebugInfo - Clear the dangling debug information |
| /// map. This function is separated from the clear so that debug |
| /// information that is dangling in a basic block can be properly |
| /// resolved in a different basic block. This allows the |
| /// SelectionDAG to resolve dangling debug information attached |
| /// to PHI nodes. |
| void clearDanglingDebugInfo(); |
| |
| /// getRoot - Return the current virtual root of the Selection DAG, |
| /// flushing any PendingLoad items. This must be done before emitting |
| /// a store or any other node that may need to be ordered after any |
| /// prior load instructions. |
| /// |
| SDValue getRoot(); |
| |
| /// getControlRoot - Similar to getRoot, but instead of flushing all the |
| /// PendingLoad items, flush all the PendingExports items. It is necessary |
| /// to do this before emitting a terminator instruction. |
| /// |
| SDValue getControlRoot(); |
| |
| 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); |
| |
| 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); |
| SDValue getValue(const Value *V); |
| bool findValue(const Value *V) const; |
| |
| SDValue getNonRegisterValue(const Value *V); |
| SDValue getValueImpl(const Value *V); |
| |
| void setValue(const Value *V, SDValue NewN) { |
| SDValue &N = NodeMap[V]; |
| assert(!N.getNode() && "Already set a value for this node!"); |
| N = NewN; |
| } |
| |
| void setUnusedArgValue(const Value *V, SDValue NewN) { |
| SDValue &N = UnusedArgNodeMap[V]; |
| 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, |
| Instruction::BinaryOps Opc, BranchProbability TW, |
| BranchProbability FW); |
| void EmitBranchForMergedCondition(const Value *Cond, MachineBasicBlock *TBB, |
| MachineBasicBlock *FBB, |
| MachineBasicBlock *CurBB, |
| MachineBasicBlock *SwitchBB, |
| BranchProbability TW, BranchProbability FW); |
| bool ShouldEmitAsBranches(const std::vector<CaseBlock> &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, |
| const BasicBlock *EHPadBB = nullptr); |
| |
| std::pair<SDValue, SDValue> lowerCallOperands( |
| ImmutableCallSite CS, |
| unsigned ArgIdx, |
| unsigned NumArgs, |
| SDValue Callee, |
| Type *ReturnTy, |
| const BasicBlock *EHPadBB = nullptr, |
| bool IsPatchPoint = false); |
| |
| /// UpdateSplitBlock - When an MBB was split during scheduling, update the |
| /// 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, |
| const BasicBlock *EHPadBB = nullptr); |
| private: |
| std::pair<SDValue, SDValue> |
| lowerInvokable(TargetLowering::CallLoweringInfo &CLI, |
| const BasicBlock *EHPadBB = nullptr); |
| |
| // 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); |
| void visitCleanupRet(const CleanupReturnInst &I); |
| void visitCatchSwitch(const CatchSwitchInst &I); |
| void visitCatchRet(const CatchReturnInst &I); |
| void visitCatchPad(const CatchPadInst &I); |
| void visitCleanupPad(const CleanupPadInst &CPI); |
| |
| BranchProbability getEdgeProbability(const MachineBasicBlock *Src, |
| const MachineBasicBlock *Dst) const; |
| void addSuccessorWithProb( |
| MachineBasicBlock *Src, MachineBasicBlock *Dst, |
| BranchProbability Prob = BranchProbability::getUnknown()); |
| |
| 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, |
| BranchProbability BranchProbToNext, |
| unsigned Reg, |
| BitTestCase &B, |
| MachineBasicBlock *SwitchBB); |
| void visitJumpTable(JumpTable &JT); |
| void visitJumpTableHeader(JumpTable &JT, JumpTableHeader &JTH, |
| MachineBasicBlock *SwitchBB); |
| |
| private: |
| // These all get lowered before this pass. |
| void visitInvoke(const InvokeInst &I); |
| void visitResume(const ResumeInst &I); |
| |
| void visitBinary(const User &I, unsigned OpCode); |
| void visitShift(const User &I, unsigned Opcode); |
| void visitAdd(const User &I) { visitBinary(I, ISD::ADD); } |
| void visitFAdd(const User &I) { visitBinary(I, ISD::FADD); } |
| void visitSub(const User &I) { visitBinary(I, ISD::SUB); } |
| void visitFSub(const User &I); |
| void visitMul(const User &I) { visitBinary(I, ISD::MUL); } |
| void visitFMul(const User &I) { visitBinary(I, ISD::FMUL); } |
| void visitURem(const User &I) { visitBinary(I, ISD::UREM); } |
| void visitSRem(const User &I) { visitBinary(I, ISD::SREM); } |
| void visitFRem(const User &I) { visitBinary(I, ISD::FREM); } |
| void visitUDiv(const User &I) { visitBinary(I, ISD::UDIV); } |
| void visitSDiv(const User &I); |
| void visitFDiv(const User &I) { visitBinary(I, ISD::FDIV); } |
| void visitAnd (const User &I) { visitBinary(I, ISD::AND); } |
| void visitOr (const User &I) { visitBinary(I, ISD::OR); } |
| void visitXor (const User &I) { visitBinary(I, ISD::XOR); } |
| void visitShl (const User &I) { visitShift(I, ISD::SHL); } |
| void visitLShr(const User &I) { visitShift(I, ISD::SRL); } |
| void visitAShr(const User &I) { visitShift(I, ISD::SRA); } |
| void visitICmp(const User &I); |
| void visitFCmp(const User &I); |
| // Visit the conversion instructions |
| void visitTrunc(const User &I); |
| void visitZExt(const User &I); |
| void visitSExt(const User &I); |
| void visitFPTrunc(const User &I); |
| void visitFPExt(const User &I); |
| void visitFPToUI(const User &I); |
| void visitFPToSI(const User &I); |
| void visitUIToFP(const User &I); |
| void visitSIToFP(const User &I); |
| 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); |
| void visitShuffleVector(const User &I); |
| |
| void visitExtractValue(const ExtractValueInst &I); |
| void visitInsertValue(const InsertValueInst &I); |
| void visitLandingPad(const LandingPadInst &I); |
| |
| void visitGetElementPtr(const User &I); |
| void visitSelect(const User &I); |
| |
| 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 visitMaskedGather(const CallInst &I); |
| void visitMaskedScatter(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); |
| |
| void visitInlineAsm(ImmutableCallSite CS); |
| const char *visitIntrinsicCall(const CallInst &I, unsigned Intrinsic); |
| void visitTargetIntrinsic(const CallInst &I, unsigned Intrinsic); |
| |
| void visitVAStart(const CallInst &I); |
| void visitVAArg(const VAArgInst &I); |
| void visitVAEnd(const CallInst &I); |
| void visitVACopy(const CallInst &I); |
| void visitStackmap(const CallInst &I); |
| void visitPatchpoint(ImmutableCallSite CS, |
| const BasicBlock *EHPadBB = 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!"); |
| } |
| void visitUserOp2(const Instruction &I) { |
| 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 |
| /// instruction selection, they will be inserted to the entry BB. |
| bool EmitFuncArgumentDbgValue(const Value *V, DILocalVariable *Variable, |
| DIExpression *Expr, DILocation *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); |
| }; |
| |
| /// RegsForValue - This struct represents the registers (physical or virtual) |
| /// that a particular set of values is assigned, and the type information about |
| /// the value. The most common situation is to represent one value at a time, |
| /// but struct or array values are handled element-wise as multiple values. The |
| /// splitting of aggregates is performed recursively, so that we never have |
| /// aggregate-typed registers. The values at this point do not necessarily have |
| /// legal types, so each value may require one or more registers of some legal |
| /// type. |
| /// |
| struct RegsForValue { |
| /// ValueVTs - The value types of the values, which may not be legal, and |
| /// may need be promoted or synthesized from one or more registers. |
| /// |
| SmallVector<EVT, 4> ValueVTs; |
| |
| /// RegVTs - The value types of the registers. This is the same size as |
| /// ValueVTs and it records, for each value, what the type of the assigned |
| /// register or registers are. (Individual values are never synthesized |
| /// from more than one type of register.) |
| /// |
| /// With virtual registers, the contents of RegVTs is redundant with TLI's |
| /// getRegisterType member function, however when with physical registers |
| /// it is necessary to have a separate record of the types. |
| /// |
| SmallVector<MVT, 4> RegVTs; |
| |
| /// Regs - This list holds the registers assigned to the values. |
| /// Each legal or promoted value requires one register, and each |
| /// expanded value requires multiple registers. |
| /// |
| SmallVector<unsigned, 4> Regs; |
| |
| RegsForValue(); |
| |
| RegsForValue(const SmallVector<unsigned, 4> ®s, MVT regvt, EVT valuevt); |
| |
| RegsForValue(LLVMContext &Context, const TargetLowering &TLI, |
| const DataLayout &DL, unsigned Reg, Type *Ty); |
| |
| /// append - Add the specified values to this one. |
| void append(const RegsForValue &RHS) { |
| ValueVTs.append(RHS.ValueVTs.begin(), RHS.ValueVTs.end()); |
| RegVTs.append(RHS.RegVTs.begin(), RHS.RegVTs.end()); |
| Regs.append(RHS.Regs.begin(), RHS.Regs.end()); |
| } |
| |
| /// getCopyFromRegs - Emit a series of CopyFromReg nodes that copies from |
| /// this value and returns the result as a ValueVTs value. This uses |
| /// Chain/Flag as the input and updates them for the output Chain/Flag. |
| /// If the Flag pointer is NULL, no flag is used. |
| SDValue getCopyFromRegs(SelectionDAG &DAG, FunctionLoweringInfo &FuncInfo, |
| SDLoc dl, |
| SDValue &Chain, SDValue *Flag, |
| const Value *V = nullptr) const; |
| |
| /// getCopyToRegs - Emit a series of CopyToReg nodes that copies the specified |
| /// value into the registers specified by this object. This uses Chain/Flag |
| /// as the input and updates them for the output Chain/Flag. If the Flag |
| /// pointer is nullptr, no flag is used. If V is not nullptr, then it is used |
| /// in printing better diagnostic messages on error. |
| void |
| getCopyToRegs(SDValue Val, SelectionDAG &DAG, SDLoc dl, SDValue &Chain, |
| SDValue *Flag, const Value *V = nullptr, |
| ISD::NodeType PreferredExtendType = ISD::ANY_EXTEND) const; |
| |
| /// AddInlineAsmOperands - Add this value to the specified inlineasm node |
| /// operand list. This adds the code marker, matching input operand index |
| /// (if applicable), and includes the number of values added into it. |
| void AddInlineAsmOperands(unsigned Kind, |
| bool HasMatching, unsigned MatchingIdx, SDLoc dl, |
| SelectionDAG &DAG, |
| std::vector<SDValue> &Ops) const; |
| }; |
| |
| } // end namespace llvm |
| |
| #endif |