clang-tools  8.0.0
UseUsingCheck.cpp
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1 //===--- UseUsingCheck.cpp - clang-tidy------------------------------------===//
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 #include "UseUsingCheck.h"
11 #include "clang/AST/ASTContext.h"
12 #include "clang/Lex/Lexer.h"
13 
14 using namespace clang::ast_matchers;
15 
16 namespace clang {
17 namespace tidy {
18 namespace modernize {
19 
20 UseUsingCheck::UseUsingCheck(StringRef Name, ClangTidyContext *Context)
21  : ClangTidyCheck(Name, Context),
22  IgnoreMacros(Options.getLocalOrGlobal("IgnoreMacros", true)) {}
23 
24 void UseUsingCheck::registerMatchers(MatchFinder *Finder) {
25  if (!getLangOpts().CPlusPlus11)
26  return;
27  Finder->addMatcher(typedefDecl(unless(isInstantiated())).bind("typedef"),
28  this);
29 }
30 
31 // Checks if 'typedef' keyword can be removed - we do it only if
32 // it is the only declaration in a declaration chain.
33 static bool CheckRemoval(SourceManager &SM, SourceLocation StartLoc,
34  ASTContext &Context) {
35  assert(StartLoc.isFileID() && "StartLoc must not be in a macro");
36  std::pair<FileID, unsigned> LocInfo = SM.getDecomposedLoc(StartLoc);
37  StringRef File = SM.getBufferData(LocInfo.first);
38  const char *TokenBegin = File.data() + LocInfo.second;
39  Lexer DeclLexer(SM.getLocForStartOfFile(LocInfo.first), Context.getLangOpts(),
40  File.begin(), TokenBegin, File.end());
41 
42  Token Tok;
43  int ParenLevel = 0;
44  bool FoundTypedef = false;
45 
46  while (!DeclLexer.LexFromRawLexer(Tok) && !Tok.is(tok::semi)) {
47  switch (Tok.getKind()) {
48  case tok::l_brace:
49  case tok::r_brace:
50  // This might be the `typedef struct {...} T;` case.
51  return false;
52  case tok::l_paren:
53  ParenLevel++;
54  break;
55  case tok::r_paren:
56  ParenLevel--;
57  break;
58  case tok::comma:
59  if (ParenLevel == 0) {
60  // If there is comma and we are not between open parenthesis then it is
61  // two or more declarations in this chain.
62  return false;
63  }
64  break;
65  case tok::raw_identifier:
66  if (Tok.getRawIdentifier() == "typedef") {
67  FoundTypedef = true;
68  }
69  break;
70  default:
71  break;
72  }
73  }
74 
75  // Sanity check against weird macro cases.
76  return FoundTypedef;
77 }
78 
79 void UseUsingCheck::check(const MatchFinder::MatchResult &Result) {
80  const auto *MatchedDecl = Result.Nodes.getNodeAs<TypedefDecl>("typedef");
81  if (MatchedDecl->getLocation().isInvalid())
82  return;
83 
84  auto &Context = *Result.Context;
85  auto &SM = *Result.SourceManager;
86 
87  SourceLocation StartLoc = MatchedDecl->getBeginLoc();
88 
89  if (StartLoc.isMacroID() && IgnoreMacros)
90  return;
91 
92  auto Diag =
93  diag(StartLoc, "use 'using' instead of 'typedef'");
94 
95  // do not fix if there is macro or array
96  if (MatchedDecl->getUnderlyingType()->isArrayType() || StartLoc.isMacroID())
97  return;
98 
99  if (CheckRemoval(SM, StartLoc, Context)) {
100  auto printPolicy = PrintingPolicy(getLangOpts());
101  printPolicy.SuppressScope = true;
102  printPolicy.ConstantArraySizeAsWritten = true;
103  printPolicy.UseVoidForZeroParams = false;
104 
105  Diag << FixItHint::CreateReplacement(
106  MatchedDecl->getSourceRange(),
107  "using " + MatchedDecl->getNameAsString() + " = " +
108  MatchedDecl->getUnderlyingType().getAsString(printPolicy));
109  }
110 }
111 
112 } // namespace modernize
113 } // namespace tidy
114 } // namespace clang
LangOptions getLangOpts() const
Returns the language options from the context.
Definition: ClangTidy.h:187
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
Base class for all clang-tidy checks.
Definition: ClangTidy.h:127
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
static constexpr llvm::StringLiteral Name
llvm::Optional< llvm::Expected< tooling::AtomicChanges > > Result
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check&#39;s name.
Definition: ClangTidy.cpp:438
static bool CheckRemoval(SourceManager &SM, SourceLocation StartLoc, ASTContext &Context)