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/ADT/Twine.h"
18 #include "llvm/Support/SourceMgr.h"
19 #include "llvm/TableGen/Error.h"
20 #include "llvm/TableGen/Record.h"
21 #include <map>
22 
23 namespace llvm {
24   class Record;
25   class RecordVal;
26   class RecordKeeper;
27   class RecTy;
28   class Init;
29   struct ForeachLoop;
30   struct MultiClass;
31   struct SubClassReference;
32   struct SubMultiClassReference;
33 
34   struct LetRecord {
35     StringInit *Name;
36     std::vector<unsigned> Bits;
37     Init *Value;
38     SMLoc Loc;
LetRecordLetRecord39     LetRecord(StringInit *N, ArrayRef<unsigned> B, Init *V, SMLoc L)
40       : Name(N), Bits(B), Value(V), Loc(L) {
41     }
42   };
43 
44   /// RecordsEntry - Can be either a record or a foreach loop.
45   struct RecordsEntry {
46     std::unique_ptr<Record> Rec;
47     std::unique_ptr<ForeachLoop> Loop;
48 
49     void dump() const;
50 
RecordsEntryRecordsEntry51     RecordsEntry() {}
RecordsEntryRecordsEntry52     RecordsEntry(std::unique_ptr<Record> Rec) : Rec(std::move(Rec)) {}
RecordsEntryRecordsEntry53     RecordsEntry(std::unique_ptr<ForeachLoop> Loop)
54       : Loop(std::move(Loop)) {}
55   };
56 
57   /// ForeachLoop - Record the iteration state associated with a for loop.
58   /// This is used to instantiate items in the loop body.
59   ///
60   /// IterVar is allowed to be null, in which case no iteration variable is
61   /// defined in the loop at all. (This happens when a ForeachLoop is
62   /// constructed by desugaring an if statement.)
63   struct ForeachLoop {
64     SMLoc Loc;
65     VarInit *IterVar;
66     Init *ListValue;
67     std::vector<RecordsEntry> Entries;
68 
69     void dump() const;
70 
ForeachLoopForeachLoop71     ForeachLoop(SMLoc Loc, VarInit *IVar, Init *LValue)
72       : Loc(Loc), IterVar(IVar), ListValue(LValue) {}
73   };
74 
75   struct DefsetRecord {
76     SMLoc Loc;
77     RecTy *EltTy = nullptr;
78     SmallVector<Init *, 16> Elements;
79   };
80 
81 class TGLocalVarScope {
82   // A scope to hold local variable definitions from defvar.
83   std::map<std::string, Init *, std::less<>> vars;
84   std::unique_ptr<TGLocalVarScope> parent;
85 
86 public:
87   TGLocalVarScope() = default;
TGLocalVarScope(std::unique_ptr<TGLocalVarScope> parent)88   TGLocalVarScope(std::unique_ptr<TGLocalVarScope> parent)
89       : parent(std::move(parent)) {}
90 
extractParent()91   std::unique_ptr<TGLocalVarScope> extractParent() {
92     // This is expected to be called just before we are destructed, so
93     // it doesn't much matter what state we leave 'parent' in.
94     return std::move(parent);
95   }
96 
getVar(StringRef Name)97   Init *getVar(StringRef Name) const {
98     auto It = vars.find(Name);
99     if (It != vars.end())
100       return It->second;
101     if (parent)
102       return parent->getVar(Name);
103     return nullptr;
104   }
105 
varAlreadyDefined(StringRef Name)106   bool varAlreadyDefined(StringRef Name) const {
107     // When we check whether a variable is already defined, for the purpose of
108     // reporting an error on redefinition, we don't look up to the parent
109     // scope, because it's all right to shadow an outer definition with an
110     // inner one.
111     return vars.find(Name) != vars.end();
112   }
113 
addVar(StringRef Name,Init * I)114   void addVar(StringRef Name, Init *I) {
115     bool Ins = vars.insert(std::make_pair(Name, I)).second;
116     (void)Ins;
117     assert(Ins && "Local variable already exists");
118   }
119 };
120 
121 struct MultiClass {
122   Record Rec;  // Placeholder for template args and Name.
123   std::vector<RecordsEntry> Entries;
124 
125   void dump() const;
126 
MultiClassMultiClass127   MultiClass(StringRef Name, SMLoc Loc, RecordKeeper &Records) :
128     Rec(Name, Loc, Records) {}
129 };
130 
131 class TGParser {
132   TGLexer Lex;
133   std::vector<SmallVector<LetRecord, 4>> LetStack;
134   std::map<std::string, std::unique_ptr<MultiClass>> MultiClasses;
135 
136   /// Loops - Keep track of any foreach loops we are within.
137   ///
138   std::vector<std::unique_ptr<ForeachLoop>> Loops;
139 
140   SmallVector<DefsetRecord *, 2> Defsets;
141 
142   /// CurMultiClass - If we are parsing a 'multiclass' definition, this is the
143   /// current value.
144   MultiClass *CurMultiClass;
145 
146   /// CurLocalScope - Innermost of the current nested scopes for 'defvar' local
147   /// variables.
148   std::unique_ptr<TGLocalVarScope> CurLocalScope;
149 
150   // Record tracker
151   RecordKeeper &Records;
152 
153   // A "named boolean" indicating how to parse identifiers.  Usually
154   // identifiers map to some existing object but in special cases
155   // (e.g. parsing def names) no such object exists yet because we are
156   // in the middle of creating in.  For those situations, allow the
157   // parser to ignore missing object errors.
158   enum IDParseMode {
159     ParseValueMode,   // We are parsing a value we expect to look up.
160     ParseNameMode,    // We are parsing a name of an object that does not yet
161                       // exist.
162   };
163 
164 public:
TGParser(SourceMgr & SM,ArrayRef<std::string> Macros,RecordKeeper & records)165   TGParser(SourceMgr &SM, ArrayRef<std::string> Macros,
166            RecordKeeper &records)
167     : Lex(SM, Macros), CurMultiClass(nullptr), Records(records) {}
168 
169   /// ParseFile - Main entrypoint for parsing a tblgen file.  These parser
170   /// routines return true on error, or false on success.
171   bool ParseFile();
172 
Error(SMLoc L,const Twine & Msg)173   bool Error(SMLoc L, const Twine &Msg) const {
174     PrintError(L, Msg);
175     return true;
176   }
TokError(const Twine & Msg)177   bool TokError(const Twine &Msg) const {
178     return Error(Lex.getLoc(), Msg);
179   }
getDependencies()180   const TGLexer::DependenciesSetTy &getDependencies() const {
181     return Lex.getDependencies();
182   }
183 
PushLocalScope()184   TGLocalVarScope *PushLocalScope() {
185     CurLocalScope = std::make_unique<TGLocalVarScope>(std::move(CurLocalScope));
186     // Returns a pointer to the new scope, so that the caller can pass it back
187     // to PopLocalScope which will check by assertion that the pushes and pops
188     // match up properly.
189     return CurLocalScope.get();
190   }
PopLocalScope(TGLocalVarScope * ExpectedStackTop)191   void PopLocalScope(TGLocalVarScope *ExpectedStackTop) {
192     assert(ExpectedStackTop == CurLocalScope.get() &&
193            "Mismatched pushes and pops of local variable scopes");
194     CurLocalScope = CurLocalScope->extractParent();
195   }
196 
197 private: // Semantic analysis methods.
198   bool AddValue(Record *TheRec, SMLoc Loc, const RecordVal &RV);
199   bool SetValue(Record *TheRec, SMLoc Loc, Init *ValName,
200                 ArrayRef<unsigned> BitList, Init *V,
201                 bool AllowSelfAssignment = false);
202   bool AddSubClass(Record *Rec, SubClassReference &SubClass);
203   bool AddSubClass(RecordsEntry &Entry, SubClassReference &SubClass);
204   bool AddSubMultiClass(MultiClass *CurMC,
205                         SubMultiClassReference &SubMultiClass);
206 
207   using SubstStack = SmallVector<std::pair<Init *, Init *>, 8>;
208 
209   bool addEntry(RecordsEntry E);
210   bool resolve(const ForeachLoop &Loop, SubstStack &Stack, bool Final,
211                std::vector<RecordsEntry> *Dest, SMLoc *Loc = nullptr);
212   bool resolve(const std::vector<RecordsEntry> &Source, SubstStack &Substs,
213                bool Final, std::vector<RecordsEntry> *Dest,
214                SMLoc *Loc = nullptr);
215   bool addDefOne(std::unique_ptr<Record> Rec);
216 
217 private:  // Parser methods.
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 ParseTopLevelLet(MultiClass *CurMultiClass);
230   void ParseLetList(SmallVectorImpl<LetRecord> &Result);
231 
232   bool ParseObjectBody(Record *CurRec);
233   bool ParseBody(Record *CurRec);
234   bool ParseBodyItem(Record *CurRec);
235 
236   bool ParseTemplateArgList(Record *CurRec);
237   Init *ParseDeclaration(Record *CurRec, bool ParsingTemplateArgs);
238   VarInit *ParseForeachDeclaration(Init *&ForeachListValue);
239 
240   SubClassReference ParseSubClassReference(Record *CurRec, bool isDefm);
241   SubMultiClassReference ParseSubMultiClassReference(MultiClass *CurMC);
242 
243   Init *ParseIDValue(Record *CurRec, StringInit *Name, SMLoc NameLoc,
244                      IDParseMode Mode = ParseValueMode);
245   Init *ParseSimpleValue(Record *CurRec, RecTy *ItemType = nullptr,
246                          IDParseMode Mode = ParseValueMode);
247   Init *ParseValue(Record *CurRec, RecTy *ItemType = nullptr,
248                    IDParseMode Mode = ParseValueMode);
249   void ParseValueList(SmallVectorImpl<llvm::Init*> &Result, Record *CurRec,
250                       Record *ArgsRec = nullptr, RecTy *EltTy = nullptr);
251   void ParseDagArgList(
252       SmallVectorImpl<std::pair<llvm::Init*, StringInit*>> &Result,
253       Record *CurRec);
254   bool ParseOptionalRangeList(SmallVectorImpl<unsigned> &Ranges);
255   bool ParseOptionalBitList(SmallVectorImpl<unsigned> &Ranges);
256   void ParseRangeList(SmallVectorImpl<unsigned> &Result);
257   bool ParseRangePiece(SmallVectorImpl<unsigned> &Ranges,
258                        TypedInit *FirstItem = nullptr);
259   RecTy *ParseType();
260   Init *ParseOperation(Record *CurRec, RecTy *ItemType);
261   Init *ParseOperationCond(Record *CurRec, RecTy *ItemType);
262   RecTy *ParseOperatorType();
263   Init *ParseObjectName(MultiClass *CurMultiClass);
264   Record *ParseClassID();
265   MultiClass *ParseMultiClassID();
266   bool ApplyLetStack(Record *CurRec);
267   bool ApplyLetStack(RecordsEntry &Entry);
268 };
269 
270 } // end namespace llvm
271 
272 #endif
273