LLParser.h

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//===-- LLParser.h - Parser Class -------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
//  This file defines the parser class for .ll files.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_LIB_ASMPARSER_LLPARSER_H
#define LLVM_LIB_ASMPARSER_LLPARSER_H

#include "LLLexer.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/ModuleSummaryIndex.h"
#include "llvm/IR/Operator.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/ValueHandle.h"
#include <map>

namespace llvm {
  class Module;
  class OpaqueType;
  class Function;
  class Value;
  class BasicBlock;
  class Instruction;
  class Constant;
  class GlobalValue;
  class Comdat;
  class MDString;
  class MDNode;
  struct SlotMapping;
  class StructType;

  /// ValID - Represents a reference of a definition of some sort with no type.
  /// There are several cases where we have to parse the value but where the
  /// type can depend on later context.  This may either be a numeric reference
  /// or a symbolic (%var) reference.  This is just a discriminated union.
  struct ValID {
    enum {
      t_LocalID, t_GlobalID,           // ID in UIntVal.
      t_LocalName, t_GlobalName,       // Name in StrVal.
      t_APSInt, t_APFloat,             // Value in APSIntVal/APFloatVal.
      t_Null, t_Undef, t_Zero, t_None, // No value.
      t_EmptyArray,                    // No value:  []
      t_Constant,                      // Value in ConstantVal.
      t_InlineAsm,                     // Value in FTy/StrVal/StrVal2/UIntVal.
      t_ConstantStruct,                // Value in ConstantStructElts.
      t_PackedConstantStruct           // Value in ConstantStructElts.
    } Kind = t_LocalID;

    LLLexer::LocTy Loc;
    unsigned UIntVal;
    FunctionType *FTy = nullptr;
    std::string StrVal, StrVal2;
    APSInt APSIntVal;
    APFloat APFloatVal{0.0};
    Constant *ConstantVal;
    std::unique_ptr<Constant *[]> ConstantStructElts;

    ValID() = default;
    ValID(const ValID &RHS)
        : Kind(RHS.Kind), Loc(RHS.Loc), UIntVal(RHS.UIntVal), FTy(RHS.FTy),
          StrVal(RHS.StrVal), StrVal2(RHS.StrVal2), APSIntVal(RHS.APSIntVal),
          APFloatVal(RHS.APFloatVal), ConstantVal(RHS.ConstantVal) {
      assert(!RHS.ConstantStructElts);
    }

    bool operator<(const ValID &RHS) const {
      if (Kind == t_LocalID || Kind == t_GlobalID)
        return UIntVal < RHS.UIntVal;
      assert((Kind == t_LocalName || Kind == t_GlobalName ||
              Kind == t_ConstantStruct || Kind == t_PackedConstantStruct) &&
             "Ordering not defined for this ValID kind yet");
      return StrVal < RHS.StrVal;
    }
  };

  class LLParser {
  public:
    typedef LLLexer::LocTy LocTy;
  private:
    LLVMContext &Context;
    LLLexer Lex;
    // Module being parsed, null if we are only parsing summary index.
    Module *M;
    // Summary index being parsed, null if we are only parsing Module.
    ModuleSummaryIndex *Index;
    SlotMapping *Slots;

    // Instruction metadata resolution.  Each instruction can have a list of
    // MDRef info associated with them.
    //
    // The simpler approach of just creating temporary MDNodes and then calling
    // RAUW on them when the definition is processed doesn't work because some
    // instruction metadata kinds, such as dbg, get stored in the IR in an
    // "optimized" format which doesn't participate in the normal value use
    // lists. This means that RAUW doesn't work, even on temporary MDNodes
    // which otherwise support RAUW. Instead, we defer resolving MDNode
    // references until the definitions have been processed.
    struct MDRef {
      SMLoc Loc;
      unsigned MDKind, MDSlot;
    };

    SmallVector<Instruction*, 64> InstsWithTBAATag;

    // Type resolution handling data structures.  The location is set when we
    // have processed a use of the type but not a definition yet.
    StringMap<std::pair<Type*, LocTy> > NamedTypes;
    std::map<unsigned, std::pair<Type*, LocTy> > NumberedTypes;

    std::map<unsigned, TrackingMDNodeRef> NumberedMetadata;
    std::map<unsigned, std::pair<TempMDTuple, LocTy>> ForwardRefMDNodes;

    // Global Value reference information.
    std::map<std::string, std::pair<GlobalValue*, LocTy> > ForwardRefVals;
    std::map<unsigned, std::pair<GlobalValue*, LocTy> > ForwardRefValIDs;
    std::vector<GlobalValue*> NumberedVals;

    // Comdat forward reference information.
    std::map<std::string, LocTy> ForwardRefComdats;

    // References to blockaddress.  The key is the function ValID, the value is
    // a list of references to blocks in that function.
    std::map<ValID, std::map<ValID, GlobalValue *>> ForwardRefBlockAddresses;
    class PerFunctionState;
    /// Reference to per-function state to allow basic blocks to be
    /// forward-referenced by blockaddress instructions within the same
    /// function.
    PerFunctionState *BlockAddressPFS;

    // Attribute builder reference information.
    std::map<Value*, std::vector<unsigned> > ForwardRefAttrGroups;
    std::map<unsigned, AttrBuilder> NumberedAttrBuilders;

    // Summary global value reference information.
    std::map<unsigned, std::vector<std::pair<ValueInfo *, LocTy>>>
        ForwardRefValueInfos;
    std::map<unsigned, std::vector<std::pair<AliasSummary *, LocTy>>>
        ForwardRefAliasees;
    std::vector<ValueInfo> NumberedValueInfos;

    // Summary type id reference information.
    std::map<unsigned, std::vector<std::pair<GlobalValue::GUID *, LocTy>>>
        ForwardRefTypeIds;

    // Map of module ID to path.
    std::map<unsigned, StringRef> ModuleIdMap;

    /// Only the llvm-as tool may set this to false to bypass
    /// UpgradeDebuginfo so it can generate broken bitcode.
    bool UpgradeDebugInfo;

    /// DataLayout string to override that in LLVM assembly.
    StringRef DataLayoutStr;

    std::string SourceFileName;

  public:
    LLParser(StringRef F, SourceMgr &SM, SMDiagnostic &Err, Module *M,
             ModuleSummaryIndex *Index, LLVMContext &Context,
             SlotMapping *Slots = nullptr, bool UpgradeDebugInfo = true,
             StringRef DataLayoutString = "")
        : Context(Context), Lex(F, SM, Err, Context), M(M), Index(Index),
          Slots(Slots), BlockAddressPFS(nullptr),
          UpgradeDebugInfo(UpgradeDebugInfo), DataLayoutStr(DataLayoutString) {
      if (!DataLayoutStr.empty())
        M->setDataLayout(DataLayoutStr);
    }
    bool Run();

    bool parseStandaloneConstantValue(Constant *&C, const SlotMapping *Slots);

    bool parseTypeAtBeginning(Type *&Ty, unsigned &Read,
                              const SlotMapping *Slots);

    LLVMContext &getContext() { return Context; }

  private:

    bool Error(LocTy L, const Twine &Msg) const {
      return Lex.Error(L, Msg);
    }
    bool TokError(const Twine &Msg) const {
      return Error(Lex.getLoc(), Msg);
    }

    /// Restore the internal name and slot mappings using the mappings that
    /// were created at an earlier parsing stage.
    void restoreParsingState(const SlotMapping *Slots);

    /// GetGlobalVal - Get a value with the specified name or ID, creating a
    /// forward reference record if needed.  This can return null if the value
    /// exists but does not have the right type.
    GlobalValue *GetGlobalVal(const std::string &N, Type *Ty, LocTy Loc,
                              bool IsCall);
    GlobalValue *GetGlobalVal(unsigned ID, Type *Ty, LocTy Loc, bool IsCall);

    /// Get a Comdat with the specified name, creating a forward reference
    /// record if needed.
    Comdat *getComdat(const std::string &Name, LocTy Loc);

    // Helper Routines.
    bool ParseToken(lltok::Kind T, const char *ErrMsg);
    bool EatIfPresent(lltok::Kind T) {
      if (Lex.getKind() != T) return false;
      Lex.Lex();
      return true;
    }

    FastMathFlags EatFastMathFlagsIfPresent() {
      FastMathFlags FMF;
      while (true)
        switch (Lex.getKind()) {
        case lltok::kw_fast: FMF.setFast();            Lex.Lex(); continue;
        case lltok::kw_nnan: FMF.setNoNaNs();          Lex.Lex(); continue;
        case lltok::kw_ninf: FMF.setNoInfs();          Lex.Lex(); continue;
        case lltok::kw_nsz:  FMF.setNoSignedZeros();   Lex.Lex(); continue;
        case lltok::kw_arcp: FMF.setAllowReciprocal(); Lex.Lex(); continue;
        case lltok::kw_contract:
          FMF.setAllowContract(true);
          Lex.Lex();
          continue;
        case lltok::kw_reassoc: FMF.setAllowReassoc(); Lex.Lex(); continue;
        case lltok::kw_afn:     FMF.setApproxFunc();   Lex.Lex(); continue;
        default: return FMF;
        }
      return FMF;
    }

    bool ParseOptionalToken(lltok::Kind T, bool &Present,
                            LocTy *Loc = nullptr) {
      if (Lex.getKind() != T) {
        Present = false;
      } else {
        if (Loc)
          *Loc = Lex.getLoc();
        Lex.Lex();
        Present = true;
      }
      return false;
    }
    bool ParseStringConstant(std::string &Result);
    bool ParseUInt32(unsigned &Val);
    bool ParseUInt32(unsigned &Val, LocTy &Loc) {
      Loc = Lex.getLoc();
      return ParseUInt32(Val);
    }
    bool ParseUInt64(uint64_t &Val);
    bool ParseUInt64(uint64_t &Val, LocTy &Loc) {
      Loc = Lex.getLoc();
      return ParseUInt64(Val);
    }
    bool ParseFlag(unsigned &Val);

    bool ParseStringAttribute(AttrBuilder &B);

    bool ParseTLSModel(GlobalVariable::ThreadLocalMode &TLM);
    bool ParseOptionalThreadLocal(GlobalVariable::ThreadLocalMode &TLM);
    bool ParseOptionalUnnamedAddr(GlobalVariable::UnnamedAddr &UnnamedAddr);
    bool ParseOptionalAddrSpace(unsigned &AddrSpace, unsigned DefaultAS = 0);
    bool ParseOptionalProgramAddrSpace(unsigned &AddrSpace) {
      return ParseOptionalAddrSpace(
          AddrSpace, M->getDataLayout().getProgramAddressSpace());
    };
    bool ParseOptionalParamAttrs(AttrBuilder &B);
    bool ParseOptionalReturnAttrs(AttrBuilder &B);
    bool ParseOptionalLinkage(unsigned &Res, bool &HasLinkage,
                              unsigned &Visibility, unsigned &DLLStorageClass,
                              bool &DSOLocal);
    void ParseOptionalDSOLocal(bool &DSOLocal);
    void ParseOptionalVisibility(unsigned &Res);
    void ParseOptionalDLLStorageClass(unsigned &Res);
    bool ParseOptionalCallingConv(unsigned &CC);
    bool ParseOptionalAlignment(unsigned &Alignment);
    bool ParseOptionalDerefAttrBytes(lltok::Kind AttrKind, uint64_t &Bytes);
    bool ParseScopeAndOrdering(bool isAtomic, SyncScope::ID &SSID,
                               AtomicOrdering &Ordering);
    bool ParseScope(SyncScope::ID &SSID);
    bool ParseOrdering(AtomicOrdering &Ordering);
    bool ParseOptionalStackAlignment(unsigned &Alignment);
    bool ParseOptionalCommaAlign(unsigned &Alignment, bool &AteExtraComma);
    bool ParseOptionalCommaAddrSpace(unsigned &AddrSpace, LocTy &Loc,
                                     bool &AteExtraComma);
    bool ParseOptionalCommaInAlloca(bool &IsInAlloca);
    bool parseAllocSizeArguments(unsigned &BaseSizeArg,
                                 Optional<unsigned> &HowManyArg);
    bool ParseIndexList(SmallVectorImpl<unsigned> &Indices,
                        bool &AteExtraComma);
    bool ParseIndexList(SmallVectorImpl<unsigned> &Indices) {
      bool AteExtraComma;
      if (ParseIndexList(Indices, AteExtraComma)) return true;
      if (AteExtraComma)
        return TokError("expected index");
      return false;
    }

    // Top-Level Entities
    bool ParseTopLevelEntities();
    bool ValidateEndOfModule();
    bool ValidateEndOfIndex();
    bool ParseTargetDefinition();
    bool ParseModuleAsm();
    bool ParseSourceFileName();
    bool ParseDepLibs();        // FIXME: Remove in 4.0.
    bool ParseUnnamedType();
    bool ParseNamedType();
    bool ParseDeclare();
    bool ParseDefine();

    bool ParseGlobalType(bool &IsConstant);
    bool ParseUnnamedGlobal();
    bool ParseNamedGlobal();
    bool ParseGlobal(const std::string &Name, LocTy NameLoc, unsigned Linkage,
                     bool HasLinkage, unsigned Visibility,
                     unsigned DLLStorageClass, bool DSOLocal,
                     GlobalVariable::ThreadLocalMode TLM,
                     GlobalVariable::UnnamedAddr UnnamedAddr);
    bool parseIndirectSymbol(const std::string &Name, LocTy NameLoc,
                             unsigned L, unsigned Visibility,
                             unsigned DLLStorageClass, bool DSOLocal,
                             GlobalVariable::ThreadLocalMode TLM,
                             GlobalVariable::UnnamedAddr UnnamedAddr);
    bool parseComdat();
    bool ParseStandaloneMetadata();
    bool ParseNamedMetadata();
    bool ParseMDString(MDString *&Result);
    bool ParseMDNodeID(MDNode *&Result);
    bool ParseUnnamedAttrGrp();
    bool ParseFnAttributeValuePairs(AttrBuilder &B,
                                    std::vector<unsigned> &FwdRefAttrGrps,
                                    bool inAttrGrp, LocTy &BuiltinLoc);
    bool ParseByValWithOptionalType(Type *&Result);

    // Module Summary Index Parsing.
    bool SkipModuleSummaryEntry();
    bool ParseSummaryEntry();
    bool ParseModuleEntry(unsigned ID);
    bool ParseModuleReference(StringRef &ModulePath);
    bool ParseGVReference(ValueInfo &VI, unsigned &GVId);
    bool ParseGVEntry(unsigned ID);
    bool ParseFunctionSummary(std::string Name, GlobalValue::GUID, unsigned ID);
    bool ParseVariableSummary(std::string Name, GlobalValue::GUID, unsigned ID);
    bool ParseAliasSummary(std::string Name, GlobalValue::GUID, unsigned ID);
    bool ParseGVFlags(GlobalValueSummary::GVFlags &GVFlags);
    bool ParseGVarFlags(GlobalVarSummary::GVarFlags &GVarFlags);
    bool ParseOptionalFFlags(FunctionSummary::FFlags &FFlags);
    bool ParseOptionalCalls(std::vector<FunctionSummary::EdgeTy> &Calls);
    bool ParseHotness(CalleeInfo::HotnessType &Hotness);
    bool ParseOptionalTypeIdInfo(FunctionSummary::TypeIdInfo &TypeIdInfo);
    bool ParseTypeTests(std::vector<GlobalValue::GUID> &TypeTests);
    bool ParseVFuncIdList(lltok::Kind Kind,
                          std::vector<FunctionSummary::VFuncId> &VFuncIdList);
    bool ParseConstVCallList(
        lltok::Kind Kind,
        std::vector<FunctionSummary::ConstVCall> &ConstVCallList);
    using IdToIndexMapType =
        std::map<unsigned, std::vector<std::pair<unsigned, LocTy>>>;
    bool ParseConstVCall(FunctionSummary::ConstVCall &ConstVCall,
                         IdToIndexMapType &IdToIndexMap, unsigned Index);
    bool ParseVFuncId(FunctionSummary::VFuncId &VFuncId,
                      IdToIndexMapType &IdToIndexMap, unsigned Index);
    bool ParseOptionalVTableFuncs(VTableFuncList &VTableFuncs);
    bool ParseOptionalRefs(std::vector<ValueInfo> &Refs);
    bool ParseTypeIdEntry(unsigned ID);
    bool ParseTypeIdSummary(TypeIdSummary &TIS);
    bool ParseTypeIdCompatibleVtableEntry(unsigned ID);
    bool ParseTypeTestResolution(TypeTestResolution &TTRes);
    bool ParseOptionalWpdResolutions(
        std::map<uint64_t, WholeProgramDevirtResolution> &WPDResMap);
    bool ParseWpdRes(WholeProgramDevirtResolution &WPDRes);
    bool ParseOptionalResByArg(
        std::map<std::vector<uint64_t>, WholeProgramDevirtResolution::ByArg>
            &ResByArg);
    bool ParseArgs(std::vector<uint64_t> &Args);
    void AddGlobalValueToIndex(std::string Name, GlobalValue::GUID,
                               GlobalValue::LinkageTypes Linkage, unsigned ID,
                               std::unique_ptr<GlobalValueSummary> Summary);

    // Type Parsing.
    bool ParseType(Type *&Result, const Twine &Msg, bool AllowVoid = false);
    bool ParseType(Type *&Result, bool AllowVoid = false) {
      return ParseType(Result, "expected type", AllowVoid);
    }
    bool ParseType(Type *&Result, const Twine &Msg, LocTy &Loc,
                   bool AllowVoid = false) {
      Loc = Lex.getLoc();
      return ParseType(Result, Msg, AllowVoid);
    }
    bool ParseType(Type *&Result, LocTy &Loc, bool AllowVoid = false) {
      Loc = Lex.getLoc();
      return ParseType(Result, AllowVoid);
    }
    bool ParseAnonStructType(Type *&Result, bool Packed);
    bool ParseStructBody(SmallVectorImpl<Type*> &Body);
    bool ParseStructDefinition(SMLoc TypeLoc, StringRef Name,
                               std::pair<Type*, LocTy> &Entry,
                               Type *&ResultTy);

    bool ParseArrayVectorType(Type *&Result, bool isVector);
    bool ParseFunctionType(Type *&Result);

    // Function Semantic Analysis.
    class PerFunctionState {
      LLParser &P;
      Function &F;
      std::map<std::string, std::pair<Value*, LocTy> > ForwardRefVals;
      std::map<unsigned, std::pair<Value*, LocTy> > ForwardRefValIDs;
      std::vector<Value*> NumberedVals;

      /// FunctionNumber - If this is an unnamed function, this is the slot
      /// number of it, otherwise it is -1.
      int FunctionNumber;
    public:
      PerFunctionState(LLParser &p, Function &f, int functionNumber);
      ~PerFunctionState();

      Function &getFunction() const { return F; }

      bool FinishFunction();

      /// GetVal - Get a value with the specified name or ID, creating a
      /// forward reference record if needed.  This can return null if the value
      /// exists but does not have the right type.
      Value *GetVal(const std::string &Name, Type *Ty, LocTy Loc, bool IsCall);
      Value *GetVal(unsigned ID, Type *Ty, LocTy Loc, bool IsCall);

      /// SetInstName - After an instruction is parsed and inserted into its
      /// basic block, this installs its name.
      bool SetInstName(int NameID, const std::string &NameStr, LocTy NameLoc,
                       Instruction *Inst);

      /// GetBB - Get a basic block with the specified name or ID, creating a
      /// forward reference record if needed.  This can return null if the value
      /// is not a BasicBlock.
      BasicBlock *GetBB(const std::string &Name, LocTy Loc);
      BasicBlock *GetBB(unsigned ID, LocTy Loc);

      /// DefineBB - Define the specified basic block, which is either named or
      /// unnamed.  If there is an error, this returns null otherwise it returns
      /// the block being defined.
      BasicBlock *DefineBB(const std::string &Name, int NameID, LocTy Loc);

      bool resolveForwardRefBlockAddresses();
    };

    bool ConvertValIDToValue(Type *Ty, ValID &ID, Value *&V,
                             PerFunctionState *PFS, bool IsCall);

    Value *checkValidVariableType(LocTy Loc, const Twine &Name, Type *Ty,
                                  Value *Val, bool IsCall);

    bool parseConstantValue(Type *Ty, Constant *&C);
    bool ParseValue(Type *Ty, Value *&V, PerFunctionState *PFS);
    bool ParseValue(Type *Ty, Value *&V, PerFunctionState &PFS) {
      return ParseValue(Ty, V, &PFS);
    }

    bool ParseValue(Type *Ty, Value *&V, LocTy &Loc,
                    PerFunctionState &PFS) {
      Loc = Lex.getLoc();
      return ParseValue(Ty, V, &PFS);
    }

    bool ParseTypeAndValue(Value *&V, PerFunctionState *PFS);
    bool ParseTypeAndValue(Value *&V, PerFunctionState &PFS) {
      return ParseTypeAndValue(V, &PFS);
    }
    bool ParseTypeAndValue(Value *&V, LocTy &Loc, PerFunctionState &PFS) {
      Loc = Lex.getLoc();
      return ParseTypeAndValue(V, PFS);
    }
    bool ParseTypeAndBasicBlock(BasicBlock *&BB, LocTy &Loc,
                                PerFunctionState &PFS);
    bool ParseTypeAndBasicBlock(BasicBlock *&BB, PerFunctionState &PFS) {
      LocTy Loc;
      return ParseTypeAndBasicBlock(BB, Loc, PFS);
    }


    struct ParamInfo {
      LocTy Loc;
      Value *V;
      AttributeSet Attrs;
      ParamInfo(LocTy loc, Value *v, AttributeSet attrs)
          : Loc(loc), V(v), Attrs(attrs) {}
    };
    bool ParseParameterList(SmallVectorImpl<ParamInfo> &ArgList,
                            PerFunctionState &PFS,
                            bool IsMustTailCall = false,
                            bool InVarArgsFunc = false);

    bool
    ParseOptionalOperandBundles(SmallVectorImpl<OperandBundleDef> &BundleList,
                                PerFunctionState &PFS);

    bool ParseExceptionArgs(SmallVectorImpl<Value *> &Args,
                            PerFunctionState &PFS);

    // Constant Parsing.
    bool ParseValID(ValID &ID, PerFunctionState *PFS = nullptr);
    bool ParseGlobalValue(Type *Ty, Constant *&C);
    bool ParseGlobalTypeAndValue(Constant *&V);
    bool ParseGlobalValueVector(SmallVectorImpl<Constant *> &Elts,
                                Optional<unsigned> *InRangeOp = nullptr);
    bool parseOptionalComdat(StringRef GlobalName, Comdat *&C);
    bool ParseMetadataAsValue(Value *&V, PerFunctionState &PFS);
    bool ParseValueAsMetadata(Metadata *&MD, const Twine &TypeMsg,
                              PerFunctionState *PFS);
    bool ParseMetadata(Metadata *&MD, PerFunctionState *PFS);
    bool ParseMDTuple(MDNode *&MD, bool IsDistinct = false);
    bool ParseMDNode(MDNode *&N);
    bool ParseMDNodeTail(MDNode *&N);
    bool ParseMDNodeVector(SmallVectorImpl<Metadata *> &Elts);
    bool ParseMetadataAttachment(unsigned &Kind, MDNode *&MD);
    bool ParseInstructionMetadata(Instruction &Inst);
    bool ParseGlobalObjectMetadataAttachment(GlobalObject &GO);
    bool ParseOptionalFunctionMetadata(Function &F);

    template <class FieldTy>
    bool ParseMDField(LocTy Loc, StringRef Name, FieldTy &Result);
    template <class FieldTy> bool ParseMDField(StringRef Name, FieldTy &Result);
    template <class ParserTy>
    bool ParseMDFieldsImplBody(ParserTy parseField);
    template <class ParserTy>
    bool ParseMDFieldsImpl(ParserTy parseField, LocTy &ClosingLoc);
    bool ParseSpecializedMDNode(MDNode *&N, bool IsDistinct = false);

#define HANDLE_SPECIALIZED_MDNODE_LEAF(CLASS)                                  \
  bool Parse##CLASS(MDNode *&Result, bool IsDistinct);
#include "llvm/IR/Metadata.def"

    // Function Parsing.
    struct ArgInfo {
      LocTy Loc;
      Type *Ty;
      AttributeSet Attrs;
      std::string Name;
      ArgInfo(LocTy L, Type *ty, AttributeSet Attr, const std::string &N)
          : Loc(L), Ty(ty), Attrs(Attr), Name(N) {}
    };
    bool ParseArgumentList(SmallVectorImpl<ArgInfo> &ArgList, bool &isVarArg);
    bool ParseFunctionHeader(Function *&Fn, bool isDefine);
    bool ParseFunctionBody(Function &Fn);
    bool ParseBasicBlock(PerFunctionState &PFS);

    enum TailCallType { TCT_None, TCT_Tail, TCT_MustTail };

    // Instruction Parsing.  Each instruction parsing routine can return with a
    // normal result, an error result, or return having eaten an extra comma.
    enum InstResult { InstNormal = 0, InstError = 1, InstExtraComma = 2 };
    int ParseInstruction(Instruction *&Inst, BasicBlock *BB,
                         PerFunctionState &PFS);
    bool ParseCmpPredicate(unsigned &P, unsigned Opc);

    bool ParseRet(Instruction *&Inst, BasicBlock *BB, PerFunctionState &PFS);
    bool ParseBr(Instruction *&Inst, PerFunctionState &PFS);
    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 ParseCleanupRet(Instruction *&Inst, PerFunctionState &PFS);
    bool ParseCatchRet(Instruction *&Inst, PerFunctionState &PFS);
    bool ParseCatchSwitch(Instruction *&Inst, PerFunctionState &PFS);
    bool ParseCatchPad(Instruction *&Inst, PerFunctionState &PFS);
    bool ParseCleanupPad(Instruction *&Inst, PerFunctionState &PFS);
    bool ParseCallBr(Instruction *&Inst, PerFunctionState &PFS);

    bool ParseUnaryOp(Instruction *&Inst, PerFunctionState &PFS, unsigned Opc,
                      bool IsFP);
    bool ParseArithmetic(Instruction *&Inst, PerFunctionState &PFS, unsigned Opc,
                         bool IsFP);
    bool ParseLogical(Instruction *&Inst, PerFunctionState &PFS, unsigned Opc);
    bool ParseCompare(Instruction *&Inst, PerFunctionState &PFS, unsigned Opc);
    bool ParseCast(Instruction *&Inst, PerFunctionState &PFS, unsigned Opc);
    bool ParseSelect(Instruction *&Inst, PerFunctionState &PFS);
    bool ParseVA_Arg(Instruction *&Inst, PerFunctionState &PFS);
    bool ParseExtractElement(Instruction *&Inst, PerFunctionState &PFS);
    bool ParseInsertElement(Instruction *&Inst, PerFunctionState &PFS);
    bool ParseShuffleVector(Instruction *&Inst, PerFunctionState &PFS);
    int ParsePHI(Instruction *&Inst, PerFunctionState &PFS);
    bool ParseLandingPad(Instruction *&Inst, PerFunctionState &PFS);
    bool ParseCall(Instruction *&Inst, PerFunctionState &PFS,
                   CallInst::TailCallKind TCK);
    int ParseAlloc(Instruction *&Inst, PerFunctionState &PFS);
    int ParseLoad(Instruction *&Inst, PerFunctionState &PFS);
    int ParseStore(Instruction *&Inst, PerFunctionState &PFS);
    int ParseCmpXchg(Instruction *&Inst, PerFunctionState &PFS);
    int ParseAtomicRMW(Instruction *&Inst, PerFunctionState &PFS);
    int ParseFence(Instruction *&Inst, PerFunctionState &PFS);
    int ParseGetElementPtr(Instruction *&Inst, PerFunctionState &PFS);
    int ParseExtractValue(Instruction *&Inst, PerFunctionState &PFS);
    int ParseInsertValue(Instruction *&Inst, PerFunctionState &PFS);

    // Use-list order directives.
    bool ParseUseListOrder(PerFunctionState *PFS = nullptr);
    bool ParseUseListOrderBB();
    bool ParseUseListOrderIndexes(SmallVectorImpl<unsigned> &Indexes);
    bool sortUseListOrder(Value *V, ArrayRef<unsigned> Indexes, SMLoc Loc);
  };
} // End llvm namespace

#endif