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