TokenRewriter.cpp revision 360660 
1//===- TokenRewriter.cpp - Token-based code rewriting interface -----------===//
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 file implements the TokenRewriter class, which is used for code
10//  transformations.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/Rewrite/Core/TokenRewriter.h"
15#include "clang/Basic/SourceManager.h"
16#include "clang/Lex/Lexer.h"
17#include "clang/Lex/ScratchBuffer.h"
18#include "clang/Lex/Token.h"
19#include <cassert>
20#include <cstring>
21#include <map>
22#include <utility>
23
24using namespace clang;
25
26TokenRewriter::TokenRewriter(FileID FID, SourceManager &SM,
27                             const LangOptions &LangOpts) {
28  ScratchBuf.reset(new ScratchBuffer(SM));
29
30  // Create a lexer to lex all the tokens of the main file in raw mode.
31  const llvm::MemoryBuffer *FromFile = SM.getBuffer(FID);
32  Lexer RawLex(FID, FromFile, SM, LangOpts);
33
34  // Return all comments and whitespace as tokens.
35  RawLex.SetKeepWhitespaceMode(true);
36
37  // Lex the file, populating our datastructures.
38  Token RawTok;
39  RawLex.LexFromRawLexer(RawTok);
40  while (RawTok.isNot(tok::eof)) {
41#if 0
42    if (Tok.is(tok::raw_identifier)) {
43      // Look up the identifier info for the token.  This should use
44      // IdentifierTable directly instead of PP.
45      PP.LookUpIdentifierInfo(Tok);
46    }
47#endif
48
49    AddToken(RawTok, TokenList.end());
50    RawLex.LexFromRawLexer(RawTok);
51  }
52}
53
54TokenRewriter::~TokenRewriter() = default;
55
56/// RemapIterator - Convert from token_iterator (a const iterator) to
57/// TokenRefTy (a non-const iterator).
58TokenRewriter::TokenRefTy TokenRewriter::RemapIterator(token_iterator I) {
59  if (I == token_end()) return TokenList.end();
60
61  // FIXME: This is horrible, we should use our own list or something to avoid
62  // this.
63  std::map<SourceLocation, TokenRefTy>::iterator MapIt =
64    TokenAtLoc.find(I->getLocation());
65  assert(MapIt != TokenAtLoc.end() && "iterator not in rewriter?");
66  return MapIt->second;
67}
68
69/// AddToken - Add the specified token into the Rewriter before the other
70/// position.
71TokenRewriter::TokenRefTy
72TokenRewriter::AddToken(const Token &T, TokenRefTy Where) {
73  Where = TokenList.insert(Where, T);
74
75  bool InsertSuccess = TokenAtLoc.insert(std::make_pair(T.getLocation(),
76                                                        Where)).second;
77  assert(InsertSuccess && "Token location already in rewriter!");
78  (void)InsertSuccess;
79  return Where;
80}
81
82TokenRewriter::token_iterator
83TokenRewriter::AddTokenBefore(token_iterator I, const char *Val) {
84  unsigned Len = strlen(Val);
85
86  // Plop the string into the scratch buffer, then create a token for this
87  // string.
88  Token Tok;
89  Tok.startToken();
90  const char *Spelling;
91  Tok.setLocation(ScratchBuf->getToken(Val, Len, Spelling));
92  Tok.setLength(Len);
93
94  // TODO: Form a whole lexer around this and relex the token!  For now, just
95  // set kind to tok::unknown.
96  Tok.setKind(tok::unknown);
97
98  return AddToken(Tok, RemapIterator(I));
99}
100