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      1 //===- TGParser.h - Parser for TableGen Files -------------------*- C++ -*-===//
      2 //
      3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
      4 // See https://llvm.org/LICENSE.txt for license information.
      5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
      6 //
      7 //===----------------------------------------------------------------------===//
      8 //
      9 // This class represents the Parser for tablegen files.
     10 //
     11 //===----------------------------------------------------------------------===//
     12 
     13 #ifndef LLVM_LIB_TABLEGEN_TGPARSER_H
     14 #define LLVM_LIB_TABLEGEN_TGPARSER_H
     15 
     16 #include "TGLexer.h"
     17 #include "llvm/TableGen/Error.h"
     18 #include "llvm/TableGen/Record.h"
     19 #include <map>
     20 
     21 namespace llvm {
     22   class SourceMgr;
     23   class Twine;
     24   struct ForeachLoop;
     25   struct MultiClass;
     26   struct SubClassReference;
     27   struct SubMultiClassReference;
     28 
     29   struct LetRecord {
     30     StringInit *Name;
     31     std::vector<unsigned> Bits;
     32     Init *Value;
     33     SMLoc Loc;
     34     LetRecord(StringInit *N, ArrayRef<unsigned> B, Init *V, SMLoc L)
     35       : Name(N), Bits(B), Value(V), Loc(L) {
     36     }
     37   };
     38 
     39   /// RecordsEntry - Holds exactly one of a Record, ForeachLoop, or
     40   /// AssertionInfo.
     41   struct RecordsEntry {
     42     std::unique_ptr<Record> Rec;
     43     std::unique_ptr<ForeachLoop> Loop;
     44     std::unique_ptr<Record::AssertionInfo> Assertion;
     45 
     46     void dump() const;
     47 
     48     RecordsEntry() {}
     49     RecordsEntry(std::unique_ptr<Record> Rec) : Rec(std::move(Rec)) {}
     50     RecordsEntry(std::unique_ptr<ForeachLoop> Loop)
     51         : Loop(std::move(Loop)) {}
     52     RecordsEntry(std::unique_ptr<Record::AssertionInfo> Assertion)
     53         : Assertion(std::move(Assertion)) {}
     54   };
     55 
     56   /// ForeachLoop - Record the iteration state associated with a for loop.
     57   /// This is used to instantiate items in the loop body.
     58   ///
     59   /// IterVar is allowed to be null, in which case no iteration variable is
     60   /// defined in the loop at all. (This happens when a ForeachLoop is
     61   /// constructed by desugaring an if statement.)
     62   struct ForeachLoop {
     63     SMLoc Loc;
     64     VarInit *IterVar;
     65     Init *ListValue;
     66     std::vector<RecordsEntry> Entries;
     67 
     68     void dump() const;
     69 
     70     ForeachLoop(SMLoc Loc, VarInit *IVar, Init *LValue)
     71       : Loc(Loc), IterVar(IVar), ListValue(LValue) {}
     72   };
     73 
     74   struct DefsetRecord {
     75     SMLoc Loc;
     76     RecTy *EltTy = nullptr;
     77     SmallVector<Init *, 16> Elements;
     78   };
     79 
     80 class TGLocalVarScope {
     81   // A scope to hold local variable definitions from defvar.
     82   std::map<std::string, Init *, std::less<>> vars;
     83   std::unique_ptr<TGLocalVarScope> parent;
     84 
     85 public:
     86   TGLocalVarScope() = default;
     87   TGLocalVarScope(std::unique_ptr<TGLocalVarScope> parent)
     88       : parent(std::move(parent)) {}
     89 
     90   std::unique_ptr<TGLocalVarScope> extractParent() {
     91     // This is expected to be called just before we are destructed, so
     92     // it doesn't much matter what state we leave 'parent' in.
     93     return std::move(parent);
     94   }
     95 
     96   Init *getVar(StringRef Name) const {
     97     auto It = vars.find(Name);
     98     if (It != vars.end())
     99       return It->second;
    100     if (parent)
    101       return parent->getVar(Name);
    102     return nullptr;
    103   }
    104 
    105   bool varAlreadyDefined(StringRef Name) const {
    106     // When we check whether a variable is already defined, for the purpose of
    107     // reporting an error on redefinition, we don't look up to the parent
    108     // scope, because it's all right to shadow an outer definition with an
    109     // inner one.
    110     return vars.find(Name) != vars.end();
    111   }
    112 
    113   void addVar(StringRef Name, Init *I) {
    114     bool Ins = vars.insert(std::make_pair(std::string(Name), I)).second;
    115     (void)Ins;
    116     assert(Ins && "Local variable already exists");
    117   }
    118 };
    119 
    120 struct MultiClass {
    121   Record Rec;  // Placeholder for template args and Name.
    122   std::vector<RecordsEntry> Entries;
    123 
    124   void dump() const;
    125 
    126   MultiClass(StringRef Name, SMLoc Loc, RecordKeeper &Records) :
    127     Rec(Name, Loc, Records) {}
    128 };
    129 
    130 class TGParser {
    131   TGLexer Lex;
    132   std::vector<SmallVector<LetRecord, 4>> LetStack;
    133   std::map<std::string, std::unique_ptr<MultiClass>> MultiClasses;
    134 
    135   /// Loops - Keep track of any foreach loops we are within.
    136   ///
    137   std::vector<std::unique_ptr<ForeachLoop>> Loops;
    138 
    139   SmallVector<DefsetRecord *, 2> Defsets;
    140 
    141   /// CurMultiClass - If we are parsing a 'multiclass' definition, this is the
    142   /// current value.
    143   MultiClass *CurMultiClass;
    144 
    145   /// CurLocalScope - Innermost of the current nested scopes for 'defvar' local
    146   /// variables.
    147   std::unique_ptr<TGLocalVarScope> CurLocalScope;
    148 
    149   // Record tracker
    150   RecordKeeper &Records;
    151 
    152   // A "named boolean" indicating how to parse identifiers.  Usually
    153   // identifiers map to some existing object but in special cases
    154   // (e.g. parsing def names) no such object exists yet because we are
    155   // in the middle of creating in.  For those situations, allow the
    156   // parser to ignore missing object errors.
    157   enum IDParseMode {
    158     ParseValueMode,   // We are parsing a value we expect to look up.
    159     ParseNameMode,    // We are parsing a name of an object that does not yet
    160                       // exist.
    161   };
    162 
    163 public:
    164   TGParser(SourceMgr &SM, ArrayRef<std::string> Macros,
    165            RecordKeeper &records)
    166     : Lex(SM, Macros), CurMultiClass(nullptr), Records(records) {}
    167 
    168   /// ParseFile - Main entrypoint for parsing a tblgen file.  These parser
    169   /// routines return true on error, or false on success.
    170   bool ParseFile();
    171 
    172   bool Error(SMLoc L, const Twine &Msg) const {
    173     PrintError(L, Msg);
    174     return true;
    175   }
    176   bool TokError(const Twine &Msg) const {
    177     return Error(Lex.getLoc(), Msg);
    178   }
    179   const TGLexer::DependenciesSetTy &getDependencies() const {
    180     return Lex.getDependencies();
    181   }
    182 
    183   TGLocalVarScope *PushLocalScope() {
    184     CurLocalScope = std::make_unique<TGLocalVarScope>(std::move(CurLocalScope));
    185     // Returns a pointer to the new scope, so that the caller can pass it back
    186     // to PopLocalScope which will check by assertion that the pushes and pops
    187     // match up properly.
    188     return CurLocalScope.get();
    189   }
    190   void PopLocalScope(TGLocalVarScope *ExpectedStackTop) {
    191     assert(ExpectedStackTop == CurLocalScope.get() &&
    192            "Mismatched pushes and pops of local variable scopes");
    193     CurLocalScope = CurLocalScope->extractParent();
    194   }
    195 
    196 private: // Semantic analysis methods.
    197   bool AddValue(Record *TheRec, SMLoc Loc, const RecordVal &RV);
    198   bool SetValue(Record *TheRec, SMLoc Loc, Init *ValName,
    199                 ArrayRef<unsigned> BitList, Init *V,
    200                 bool AllowSelfAssignment = false);
    201   bool AddSubClass(Record *Rec, SubClassReference &SubClass);
    202   bool AddSubClass(RecordsEntry &Entry, SubClassReference &SubClass);
    203   bool AddSubMultiClass(MultiClass *CurMC,
    204                         SubMultiClassReference &SubMultiClass);
    205 
    206   using SubstStack = SmallVector<std::pair<Init *, Init *>, 8>;
    207 
    208   bool addEntry(RecordsEntry E);
    209   bool resolve(const ForeachLoop &Loop, SubstStack &Stack, bool Final,
    210                std::vector<RecordsEntry> *Dest, SMLoc *Loc = nullptr);
    211   bool resolve(const std::vector<RecordsEntry> &Source, SubstStack &Substs,
    212                bool Final, std::vector<RecordsEntry> *Dest,
    213                SMLoc *Loc = nullptr);
    214   bool addDefOne(std::unique_ptr<Record> Rec);
    215 
    216 private:  // Parser methods.
    217   bool consume(tgtok::TokKind K);
    218   bool ParseObjectList(MultiClass *MC = nullptr);
    219   bool ParseObject(MultiClass *MC);
    220   bool ParseClass();
    221   bool ParseMultiClass();
    222   bool ParseDefm(MultiClass *CurMultiClass);
    223   bool ParseDef(MultiClass *CurMultiClass);
    224   bool ParseDefset();
    225   bool ParseDefvar();
    226   bool ParseForeach(MultiClass *CurMultiClass);
    227   bool ParseIf(MultiClass *CurMultiClass);
    228   bool ParseIfBody(MultiClass *CurMultiClass, StringRef Kind);
    229   bool ParseAssert(MultiClass *CurMultiClass, Record *CurRec = nullptr);
    230   bool ParseTopLevelLet(MultiClass *CurMultiClass);
    231   void ParseLetList(SmallVectorImpl<LetRecord> &Result);
    232 
    233   bool ParseObjectBody(Record *CurRec);
    234   bool ParseBody(Record *CurRec);
    235   bool ParseBodyItem(Record *CurRec);
    236 
    237   bool ParseTemplateArgList(Record *CurRec);
    238   Init *ParseDeclaration(Record *CurRec, bool ParsingTemplateArgs);
    239   VarInit *ParseForeachDeclaration(Init *&ForeachListValue);
    240 
    241   SubClassReference ParseSubClassReference(Record *CurRec, bool isDefm);
    242   SubMultiClassReference ParseSubMultiClassReference(MultiClass *CurMC);
    243 
    244   Init *ParseIDValue(Record *CurRec, StringInit *Name, SMLoc NameLoc,
    245                      IDParseMode Mode = ParseValueMode);
    246   Init *ParseSimpleValue(Record *CurRec, RecTy *ItemType = nullptr,
    247                          IDParseMode Mode = ParseValueMode);
    248   Init *ParseValue(Record *CurRec, RecTy *ItemType = nullptr,
    249                    IDParseMode Mode = ParseValueMode);
    250   void ParseValueList(SmallVectorImpl<llvm::Init*> &Result,
    251                       Record *CurRec, RecTy *ItemType = nullptr);
    252   bool ParseTemplateArgValueList(SmallVectorImpl<llvm::Init *> &Result,
    253                                  Record *CurRec, Record *ArgsRec);
    254   void ParseDagArgList(
    255       SmallVectorImpl<std::pair<llvm::Init*, StringInit*>> &Result,
    256       Record *CurRec);
    257   bool ParseOptionalRangeList(SmallVectorImpl<unsigned> &Ranges);
    258   bool ParseOptionalBitList(SmallVectorImpl<unsigned> &Ranges);
    259   void ParseRangeList(SmallVectorImpl<unsigned> &Result);
    260   bool ParseRangePiece(SmallVectorImpl<unsigned> &Ranges,
    261                        TypedInit *FirstItem = nullptr);
    262   RecTy *ParseType();
    263   Init *ParseOperation(Record *CurRec, RecTy *ItemType);
    264   Init *ParseOperationSubstr(Record *CurRec, RecTy *ItemType);
    265   Init *ParseOperationFind(Record *CurRec, RecTy *ItemType);
    266   Init *ParseOperationForEachFilter(Record *CurRec, RecTy *ItemType);
    267   Init *ParseOperationCond(Record *CurRec, RecTy *ItemType);
    268   RecTy *ParseOperatorType();
    269   Init *ParseObjectName(MultiClass *CurMultiClass);
    270   Record *ParseClassID();
    271   MultiClass *ParseMultiClassID();
    272   bool ApplyLetStack(Record *CurRec);
    273   bool ApplyLetStack(RecordsEntry &Entry);
    274   bool CheckTemplateArgValues(SmallVectorImpl<llvm::Init *> &Values,
    275                               SMLoc Loc, Record *ArgsRec);
    276 };
    277 
    278 } // end namespace llvm
    279 
    280 #endif
    281