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      1 //===--- TokenRewriter.cpp - Token-based code rewriting interface ---------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 //  This file implements the TokenRewriter class, which is used for code
     11 //  transformations.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #include "clang/Rewrite/Core/TokenRewriter.h"
     16 #include "clang/Basic/SourceManager.h"
     17 #include "clang/Lex/Lexer.h"
     18 #include "clang/Lex/ScratchBuffer.h"
     19 using namespace clang;
     20 
     21 TokenRewriter::TokenRewriter(FileID FID, SourceManager &SM,
     22                              const LangOptions &LangOpts) {
     23   ScratchBuf.reset(new ScratchBuffer(SM));
     24 
     25   // Create a lexer to lex all the tokens of the main file in raw mode.
     26   const llvm::MemoryBuffer *FromFile = SM.getBuffer(FID);
     27   Lexer RawLex(FID, FromFile, SM, LangOpts);
     28 
     29   // Return all comments and whitespace as tokens.
     30   RawLex.SetKeepWhitespaceMode(true);
     31 
     32   // Lex the file, populating our datastructures.
     33   Token RawTok;
     34   RawLex.LexFromRawLexer(RawTok);
     35   while (RawTok.isNot(tok::eof)) {
     36 #if 0
     37     if (Tok.is(tok::raw_identifier)) {
     38       // Look up the identifier info for the token.  This should use
     39       // IdentifierTable directly instead of PP.
     40       PP.LookUpIdentifierInfo(Tok);
     41     }
     42 #endif
     43 
     44     AddToken(RawTok, TokenList.end());
     45     RawLex.LexFromRawLexer(RawTok);
     46   }
     47 }
     48 
     49 TokenRewriter::~TokenRewriter() {
     50 }
     51 
     52 
     53 /// RemapIterator - Convert from token_iterator (a const iterator) to
     54 /// TokenRefTy (a non-const iterator).
     55 TokenRewriter::TokenRefTy TokenRewriter::RemapIterator(token_iterator I) {
     56   if (I == token_end()) return TokenList.end();
     57 
     58   // FIXME: This is horrible, we should use our own list or something to avoid
     59   // this.
     60   std::map<SourceLocation, TokenRefTy>::iterator MapIt =
     61     TokenAtLoc.find(I->getLocation());
     62   assert(MapIt != TokenAtLoc.end() && "iterator not in rewriter?");
     63   return MapIt->second;
     64 }
     65 
     66 
     67 /// AddToken - Add the specified token into the Rewriter before the other
     68 /// position.
     69 TokenRewriter::TokenRefTy
     70 TokenRewriter::AddToken(const Token &T, TokenRefTy Where) {
     71   Where = TokenList.insert(Where, T);
     72 
     73   bool InsertSuccess = TokenAtLoc.insert(std::make_pair(T.getLocation(),
     74                                                         Where)).second;
     75   assert(InsertSuccess && "Token location already in rewriter!");
     76   (void)InsertSuccess;
     77   return Where;
     78 }
     79 
     80 
     81 TokenRewriter::token_iterator
     82 TokenRewriter::AddTokenBefore(token_iterator I, const char *Val) {
     83   unsigned Len = strlen(Val);
     84 
     85   // Plop the string into the scratch buffer, then create a token for this
     86   // string.
     87   Token Tok;
     88   Tok.startToken();
     89   const char *Spelling;
     90   Tok.setLocation(ScratchBuf->getToken(Val, Len, Spelling));
     91   Tok.setLength(Len);
     92 
     93   // TODO: Form a whole lexer around this and relex the token!  For now, just
     94   // set kind to tok::unknown.
     95   Tok.setKind(tok::unknown);
     96 
     97   return AddToken(Tok, RemapIterator(I));
     98 }
     99 
    100