TGParser.h

Go to the documentation of this file.

//===- TGParser.h - Parser for TableGen Files -------------------*- 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 class represents the Parser for tablegen files.
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_LIB_TABLEGEN_TGPARSER_H
#define LLVM_LIB_TABLEGEN_TGPARSER_H
 
#include "TGLexer.h"
#include "llvm/TableGen/Error.h"
#include "llvm/TableGen/Record.h"
#include <map>
 
namespace llvm {
  class SourceMgr;
  class Twine;
  struct ForeachLoop;
  struct MultiClass;
  struct SubClassReference;
  struct SubMultiClassReference;
 
  struct LetRecord {
    StringInit *Name;
    std::vector<unsigned> Bits;
    Init *Value;
    SMLoc Loc;
    LetRecord(StringInit *N, ArrayRef<unsigned> B, Init *V, SMLoc L)
      : Name(N), Bits(B), Value(V), Loc(L) {
    }
  };
 
  /// RecordsEntry - Holds exactly one of a Record, ForeachLoop, or
  /// AssertionInfo.
  struct RecordsEntry {
    std::unique_ptr<Record> Rec;
    std::unique_ptr<ForeachLoop> Loop;
    std::unique_ptr<Record::AssertionInfo> Assertion;
 
    void dump() const;
 
    RecordsEntry() = default;
    RecordsEntry(std::unique_ptr<Record> Rec) : Rec(std::move(Rec)) {}
    RecordsEntry(std::unique_ptr<ForeachLoop> Loop)
        : Loop(std::move(Loop)) {}
    RecordsEntry(std::unique_ptr<Record::AssertionInfo> Assertion)
        : Assertion(std::move(Assertion)) {}
  };
 
  /// ForeachLoop - Record the iteration state associated with a for loop.
  /// This is used to instantiate items in the loop body.
  ///
  /// IterVar is allowed to be null, in which case no iteration variable is
  /// defined in the loop at all. (This happens when a ForeachLoop is
  /// constructed by desugaring an if statement.)
  struct ForeachLoop {
    SMLoc Loc;
    VarInit *IterVar;
    Init *ListValue;
    std::vector<RecordsEntry> Entries;
 
    void dump() const;
 
    ForeachLoop(SMLoc Loc, VarInit *IVar, Init *LValue)
      : Loc(Loc), IterVar(IVar), ListValue(LValue) {}
  };
 
  struct DefsetRecord {
    SMLoc Loc;
    RecTy *EltTy = nullptr;
    SmallVector<Init *, 16> Elements;
  };
 
  struct MultiClass {
    Record Rec; // Placeholder for template args and Name.
    std::vector<RecordsEntry> Entries;
 
    void dump() const;
 
    MultiClass(StringRef Name, SMLoc Loc, RecordKeeper &Records)
        : Rec(Name, Loc, Records) {}
  };
 
  class TGVarScope {
  public:
    enum ScopeKind { SK_Local, SK_Record, SK_ForeachLoop, SK_MultiClass };
 
  private:
    ScopeKind Kind;
    std::unique_ptr<TGVarScope> Parent;
    // A scope to hold variable definitions from defvar.
    std::map<std::string, Init *, std::less<>> Vars;
    Record *CurRec = nullptr;
    ForeachLoop *CurLoop = nullptr;
    MultiClass *CurMultiClass = nullptr;
 
  public:
    TGVarScope(std::unique_ptr<TGVarScope> Parent)
        : Kind(SK_Local), Parent(std::move(Parent)) {}
    TGVarScope(std::unique_ptr<TGVarScope> Parent, Record *Rec)
        : Kind(SK_Record), Parent(std::move(Parent)), CurRec(Rec) {}
    TGVarScope(std::unique_ptr<TGVarScope> Parent, ForeachLoop *Loop)
        : Kind(SK_ForeachLoop), Parent(std::move(Parent)), CurLoop(Loop) {}
    TGVarScope(std::unique_ptr<TGVarScope> Parent, MultiClass *Multiclass)
        : Kind(SK_MultiClass), Parent(std::move(Parent)),
          CurMultiClass(Multiclass) {}
 
    std::unique_ptr<TGVarScope> extractParent() {
      // This is expected to be called just before we are destructed, so
      // it doesn't much matter what state we leave 'parent' in.
      return std::move(Parent);
    }
 
    Init *getVar(RecordKeeper &Records, MultiClass *ParsingMultiClass,
                 StringInit *Name, SMRange NameLoc,
                 bool TrackReferenceLocs) const;
 
    bool varAlreadyDefined(StringRef Name) const {
      // When we check whether a variable is already defined, for the purpose of
      // reporting an error on redefinition, we don't look up to the parent
      // scope, because it's all right to shadow an outer definition with an
      // inner one.
      return Vars.find(Name) != Vars.end();
    }
 
    void addVar(StringRef Name, Init *I) {
      bool Ins = Vars.insert(std::make_pair(std::string(Name), I)).second;
      (void)Ins;
      assert(Ins && "Local variable already exists");
    }
 
    bool isOutermost() const { return Parent == nullptr; }
  };
 
class TGParser {
  TGLexer Lex;
  std::vector<SmallVector<LetRecord, 4>> LetStack;
  std::map<std::string, std::unique_ptr<MultiClass>> MultiClasses;
 
  /// Loops - Keep track of any foreach loops we are within.
  ///
  std::vector<std::unique_ptr<ForeachLoop>> Loops;
 
  SmallVector<DefsetRecord *, 2> Defsets;
 
  /// CurMultiClass - If we are parsing a 'multiclass' definition, this is the
  /// current value.
  MultiClass *CurMultiClass;
 
  /// CurScope - Innermost of the current nested scopes for 'defvar' variables.
  std::unique_ptr<TGVarScope> CurScope;
 
  // Record tracker
  RecordKeeper &Records;
 
  // A "named boolean" indicating how to parse identifiers.  Usually
  // identifiers map to some existing object but in special cases
  // (e.g. parsing def names) no such object exists yet because we are
  // in the middle of creating in.  For those situations, allow the
  // parser to ignore missing object errors.
  enum IDParseMode {
    ParseValueMode,   // We are parsing a value we expect to look up.
    ParseNameMode,    // We are parsing a name of an object that does not yet
                      // exist.
  };
 
  bool NoWarnOnUnusedTemplateArgs = false;
  bool TrackReferenceLocs = false;
 
public:
  TGParser(SourceMgr &SM, ArrayRef<std::string> Macros, RecordKeeper &records,
           const bool NoWarnOnUnusedTemplateArgs = false,
           const bool TrackReferenceLocs = false)
      : Lex(SM, Macros), CurMultiClass(nullptr), Records(records),
        NoWarnOnUnusedTemplateArgs(NoWarnOnUnusedTemplateArgs),
        TrackReferenceLocs(TrackReferenceLocs) {}
 
  /// ParseFile - Main entrypoint for parsing a tblgen file.  These parser
  /// routines return true on error, or false on success.
  bool ParseFile();
 
  bool Error(SMLoc L, const Twine &Msg) const {
    PrintError(L, Msg);
    return true;
  }
  bool TokError(const Twine &Msg) const {
    return Error(Lex.getLoc(), Msg);
  }
  const TGLexer::DependenciesSetTy &getDependencies() const {
    return Lex.getDependencies();
  }
 
  TGVarScope *PushScope() {
    CurScope = std::make_unique<TGVarScope>(std::move(CurScope));
    // Returns a pointer to the new scope, so that the caller can pass it back
    // to PopScope which will check by assertion that the pushes and pops
    // match up properly.
    return CurScope.get();
  }
  TGVarScope *PushScope(Record *Rec) {
    CurScope = std::make_unique<TGVarScope>(std::move(CurScope), Rec);
    return CurScope.get();
  }
  TGVarScope *PushScope(ForeachLoop *Loop) {
    CurScope = std::make_unique<TGVarScope>(std::move(CurScope), Loop);
    return CurScope.get();
  }
  TGVarScope *PushScope(MultiClass *Multiclass) {
    CurScope = std::make_unique<TGVarScope>(std::move(CurScope), Multiclass);
    return CurScope.get();
  }
  void PopScope(TGVarScope *ExpectedStackTop) {
    assert(ExpectedStackTop == CurScope.get() &&
           "Mismatched pushes and pops of local variable scopes");
    CurScope = CurScope->extractParent();
  }
 
private: // Semantic analysis methods.
  bool AddValue(Record *TheRec, SMLoc Loc, const RecordVal &RV);
  /// Set the value of a RecordVal within the given record. If `OverrideDefLoc`
  /// is set, the provided location overrides any existing location of the
  /// RecordVal.
  bool SetValue(Record *TheRec, SMLoc Loc, Init *ValName,
                ArrayRef<unsigned> BitList, Init *V,
                bool AllowSelfAssignment = false, bool OverrideDefLoc = true);
  bool AddSubClass(Record *Rec, SubClassReference &SubClass);
  bool AddSubClass(RecordsEntry &Entry, SubClassReference &SubClass);
  bool AddSubMultiClass(MultiClass *CurMC,
                        SubMultiClassReference &SubMultiClass);
 
  using SubstStack = SmallVector<std::pair<Init *, Init *>, 8>;
 
  bool addEntry(RecordsEntry E);
  bool resolve(const ForeachLoop &Loop, SubstStack &Stack, bool Final,
               std::vector<RecordsEntry> *Dest, SMLoc *Loc = nullptr);
  bool resolve(const std::vector<RecordsEntry> &Source, SubstStack &Substs,
               bool Final, std::vector<RecordsEntry> *Dest,
               SMLoc *Loc = nullptr);
  bool addDefOne(std::unique_ptr<Record> Rec);
 
private:  // Parser methods.
  bool consume(tgtok::TokKind K);
  bool ParseObjectList(MultiClass *MC = nullptr);
  bool ParseObject(MultiClass *MC);
  bool ParseClass();
  bool ParseMultiClass();
  bool ParseDefm(MultiClass *CurMultiClass);
  bool ParseDef(MultiClass *CurMultiClass);
  bool ParseDefset();
  bool ParseDefvar(Record *CurRec = nullptr);
  bool ParseForeach(MultiClass *CurMultiClass);
  bool ParseIf(MultiClass *CurMultiClass);
  bool ParseIfBody(MultiClass *CurMultiClass, StringRef Kind);
  bool ParseAssert(MultiClass *CurMultiClass, Record *CurRec = nullptr);
  bool ParseTopLevelLet(MultiClass *CurMultiClass);
  void ParseLetList(SmallVectorImpl<LetRecord> &Result);
 
  bool ParseObjectBody(Record *CurRec);
  bool ParseBody(Record *CurRec);
  bool ParseBodyItem(Record *CurRec);
 
  bool ParseTemplateArgList(Record *CurRec);
  Init *ParseDeclaration(Record *CurRec, bool ParsingTemplateArgs);
  VarInit *ParseForeachDeclaration(Init *&ForeachListValue);
 
  SubClassReference ParseSubClassReference(Record *CurRec, bool isDefm);
  SubMultiClassReference ParseSubMultiClassReference(MultiClass *CurMC);
 
  Init *ParseIDValue(Record *CurRec, StringInit *Name, SMRange NameLoc,
                     IDParseMode Mode = ParseValueMode);
  Init *ParseSimpleValue(Record *CurRec, RecTy *ItemType = nullptr,
                         IDParseMode Mode = ParseValueMode);
  Init *ParseValue(Record *CurRec, RecTy *ItemType = nullptr,
                   IDParseMode Mode = ParseValueMode);
  void ParseValueList(SmallVectorImpl<llvm::Init*> &Result,
                      Record *CurRec, RecTy *ItemType = nullptr);
  bool ParseTemplateArgValueList(SmallVectorImpl<llvm::Init *> &Result,
                                 Record *CurRec, Record *ArgsRec);
  void ParseDagArgList(
      SmallVectorImpl<std::pair<llvm::Init*, StringInit*>> &Result,
      Record *CurRec);
  bool ParseOptionalRangeList(SmallVectorImpl<unsigned> &Ranges);
  bool ParseOptionalBitList(SmallVectorImpl<unsigned> &Ranges);
  TypedInit *ParseSliceElement(Record *CurRec);
  TypedInit *ParseSliceElements(Record *CurRec, bool Single = false);
  void ParseRangeList(SmallVectorImpl<unsigned> &Result);
  bool ParseRangePiece(SmallVectorImpl<unsigned> &Ranges,
                       TypedInit *FirstItem = nullptr);
  RecTy *ParseType();
  Init *ParseOperation(Record *CurRec, RecTy *ItemType);
  Init *ParseOperationSubstr(Record *CurRec, RecTy *ItemType);
  Init *ParseOperationFind(Record *CurRec, RecTy *ItemType);
  Init *ParseOperationForEachFilter(Record *CurRec, RecTy *ItemType);
  Init *ParseOperationCond(Record *CurRec, RecTy *ItemType);
  RecTy *ParseOperatorType();
  Init *ParseObjectName(MultiClass *CurMultiClass);
  Record *ParseClassID();
  MultiClass *ParseMultiClassID();
  bool ApplyLetStack(Record *CurRec);
  bool ApplyLetStack(RecordsEntry &Entry);
  bool CheckTemplateArgValues(SmallVectorImpl<llvm::Init *> &Values,
                              SMLoc Loc, Record *ArgsRec);
};
 
} // end namespace llvm
 
#endif