Rewrite the tblgen parser in a recursive descent style, eliminating the bison parser.

This makes the parser much easier to understand, eliminates a ton of global variables,
and gives tblgen nice caret diagnostics.  It is also faster, but tblgen probably doesn't
care about performance.

There are a couple of FIXMEs which I will take care of next.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44274 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 109 insertions, 0 deletions

diff --git a/utils/TableGen/TGParser.h b/utils/TableGen/TGParser.h
new file mode 100644
index 0000000000..6ec0415a57
--- /dev/null
+++ b/utils/TableGen/TGParser.h
@@ -0,0 +1,109 @@
+//===- TGParser.h - Parser for TableGen Files -------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Chris Lattner and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This class represents the Parser for tablegen files.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef TGPARSER_H
+#define TGPARSER_H
+
+#include "TGLexer.h"
+#include <map>
+
+namespace llvm {
+  class Record;
+  class RecordVal;
+  class RecTy;
+  class Init;
+  struct MultiClass;
+  struct SubClassReference;
+  
+  struct LetRecord {
+    std::string Name;
+    std::vector<unsigned> Bits;
+    Init *Value;
+    TGLexer::LocTy Loc;
+    LetRecord(const std::string &N, const std::vector<unsigned> &B, Init *V,
+              TGLexer::LocTy L)
+      : Name(N), Bits(B), Value(V), Loc(L) {
+    }
+  };
+  
+class TGParser {
+  TGLexer Lex;
+  std::vector<std::vector<LetRecord> > LetStack;
+  std::map<std::string, MultiClass*> MultiClasses;
+  
+  /// CurMultiClass - If we are parsing a 'multiclass' definition, this is the 
+  /// current value.
+  MultiClass *CurMultiClass;
+public:
+  typedef TGLexer::LocTy LocTy;
+  
+  TGParser(MemoryBuffer *StartBuf) : Lex(StartBuf), CurMultiClass(0) {}
+  
+  void setIncludeDirs(const std::vector<std::string> &D){Lex.setIncludeDirs(D);}
+
+  /// ParseFile - Main entrypoint for parsing a tblgen file.  These parser
+  /// routines return true on error, or false on success.
+  bool ParseFile();
+  
+  bool Error(LocTy L, const std::string &Msg) const {
+    Lex.PrintError(L, Msg);
+    return true;
+  }
+  bool TokError(const std::string &Msg) const {
+    return Error(Lex.getLoc(), Msg);
+  }
+private:  // Semantic analysis methods.
+  bool AddValue(Record *TheRec, LocTy Loc, const RecordVal &RV);
+  bool SetValue(Record *TheRec, LocTy Loc, const std::string &ValName, 
+                const std::vector<unsigned> &BitList, Init *V);
+  bool AddSubClass(Record *Rec, class SubClassReference &SubClass);
+
+private:  // Parser methods.
+  bool ParseObjectList();
+  bool ParseObject();
+  bool ParseClass();
+  bool ParseMultiClass();
+  bool ParseMultiClassDef(MultiClass *CurMC);
+  bool ParseDefm();
+  bool ParseTopLevelLet();
+  std::vector<LetRecord> ParseLetList();
+
+  Record *ParseDef(MultiClass *CurMultiClass);
+  bool ParseObjectBody(Record *CurRec);
+  bool ParseBody(Record *CurRec);
+  bool ParseBodyItem(Record *CurRec);
+
+  bool ParseTemplateArgList(Record *CurRec);
+  std::string ParseDeclaration(Record *CurRec, bool ParsingTemplateArgs);
+
+  SubClassReference ParseSubClassReference(Record *CurRec, bool isDefm);
+
+  Init *ParseIDValue(Record *CurRec);
+  Init *ParseIDValue(Record *CurRec, const std::string &Name, LocTy NameLoc);
+  Init *ParseSimpleValue(Record *CurRec);
+  Init *ParseValue(Record *CurRec);
+  std::vector<Init*> ParseValueList(Record *CurRec);
+  std::vector<std::pair<llvm::Init*, std::string> > ParseDagArgList(Record *);
+  bool ParseOptionalRangeList(std::vector<unsigned> &Ranges);
+  bool ParseOptionalBitList(std::vector<unsigned> &Ranges);
+  std::vector<unsigned> ParseRangeList();
+  bool ParseRangePiece(std::vector<unsigned> &Ranges);
+  RecTy *ParseType();
+  std::string ParseObjectName();
+  Record *ParseClassID();
+  Record *ParseDefmID();
+};
+  
+} // end namespace llvm
+
+#endif