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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/Lex/Lexer.h"
17 #include "clang/Lex/ScratchBuffer.h"
18 #include "clang/Basic/SourceManager.h"
19 using namespace clang;
20 
TokenRewriter(FileID FID,SourceManager & SM,const LangOptions & LangOpts)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 
~TokenRewriter()49 TokenRewriter::~TokenRewriter() {
50 }
51 
52 
53 /// RemapIterator - Convert from token_iterator (a const iterator) to
54 /// TokenRefTy (a non-const iterator).
RemapIterator(token_iterator I)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
AddToken(const Token & T,TokenRefTy Where)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
AddTokenBefore(token_iterator I,const char * Val)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