1 //===--- UseUsingCheck.cpp - clang-tidy------------------------------------===// 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 #include "UseUsingCheck.h" 10 #include "clang/AST/ASTContext.h" 11 #include "clang/Lex/Lexer.h" 12 13 using namespace clang::ast_matchers; 14 15 namespace clang { 16 namespace tidy { 17 namespace modernize { 18 19 UseUsingCheck::UseUsingCheck(StringRef Name, ClangTidyContext *Context) 20 : ClangTidyCheck(Name, Context), 21 IgnoreMacros(Options.getLocalOrGlobal("IgnoreMacros", true)) {} 22 23 void UseUsingCheck::registerMatchers(MatchFinder *Finder) { 24 if (!getLangOpts().CPlusPlus11) 25 return; 26 Finder->addMatcher(typedefDecl(unless(isInstantiated())).bind("typedef"), 27 this); 28 // This matcher used to find structs defined in source code within typedefs. 29 // They appear in the AST just *prior* to the typedefs. 30 Finder->addMatcher(cxxRecordDecl(unless(isImplicit())).bind("struct"), this); 31 } 32 33 void UseUsingCheck::check(const MatchFinder::MatchResult &Result) { 34 // Match CXXRecordDecl only to store the range of the last non-implicit full 35 // declaration, to later check whether it's within the typdef itself. 36 const auto *MatchedCxxRecordDecl = 37 Result.Nodes.getNodeAs<CXXRecordDecl>("struct"); 38 if (MatchedCxxRecordDecl) { 39 LastCxxDeclRange = MatchedCxxRecordDecl->getSourceRange(); 40 return; 41 } 42 43 const auto *MatchedDecl = Result.Nodes.getNodeAs<TypedefDecl>("typedef"); 44 if (MatchedDecl->getLocation().isInvalid()) 45 return; 46 47 SourceLocation StartLoc = MatchedDecl->getBeginLoc(); 48 49 if (StartLoc.isMacroID() && IgnoreMacros) 50 return; 51 52 static const char *UseUsingWarning = "use 'using' instead of 'typedef'"; 53 54 // Warn at StartLoc but do not fix if there is macro or array. 55 if (MatchedDecl->getUnderlyingType()->isArrayType() || StartLoc.isMacroID()) { 56 diag(StartLoc, UseUsingWarning); 57 return; 58 } 59 60 auto printPolicy = PrintingPolicy(getLangOpts()); 61 printPolicy.SuppressScope = true; 62 printPolicy.ConstantArraySizeAsWritten = true; 63 printPolicy.UseVoidForZeroParams = false; 64 65 std::string Type = MatchedDecl->getUnderlyingType().getAsString(printPolicy); 66 std::string Name = MatchedDecl->getNameAsString(); 67 SourceRange ReplaceRange = MatchedDecl->getSourceRange(); 68 69 // typedefs with multiple comma-separated definitions produce multiple 70 // consecutive TypedefDecl nodes whose SourceRanges overlap. Each range starts 71 // at the "typedef" and then continues *across* previous definitions through 72 // the end of the current TypedefDecl definition. 73 std::string Using = "using "; 74 if (ReplaceRange.getBegin().isMacroID() || 75 ReplaceRange.getBegin() >= LastReplacementEnd) { 76 // This is the first (and possibly the only) TypedefDecl in a typedef. Save 77 // Type and Name in case we find subsequent TypedefDecl's in this typedef. 78 FirstTypedefType = Type; 79 FirstTypedefName = Name; 80 } else { 81 // This is additional TypedefDecl in a comma-separated typedef declaration. 82 // Start replacement *after* prior replacement and separate with semicolon. 83 ReplaceRange.setBegin(LastReplacementEnd); 84 Using = ";\nusing "; 85 86 // If this additional TypedefDecl's Type starts with the first TypedefDecl's 87 // type, make this using statement refer back to the first type, e.g. make 88 // "typedef int Foo, *Foo_p;" -> "using Foo = int;\nusing Foo_p = Foo*;" 89 if (Type.size() > FirstTypedefType.size() && 90 Type.substr(0, FirstTypedefType.size()) == FirstTypedefType) 91 Type = FirstTypedefName + Type.substr(FirstTypedefType.size() + 1); 92 } 93 if (!ReplaceRange.getEnd().isMacroID()) 94 LastReplacementEnd = ReplaceRange.getEnd().getLocWithOffset(Name.size()); 95 96 auto Diag = diag(ReplaceRange.getBegin(), UseUsingWarning); 97 98 // If typedef contains a full struct/class declaration, extract its full text. 99 if (LastCxxDeclRange.isValid() && ReplaceRange.fullyContains(LastCxxDeclRange)) { 100 bool Invalid; 101 Type = std::string( 102 Lexer::getSourceText(CharSourceRange::getTokenRange(LastCxxDeclRange), 103 *Result.SourceManager, getLangOpts(), &Invalid)); 104 if (Invalid) 105 return; 106 } 107 108 std::string Replacement = Using + Name + " = " + Type; 109 Diag << FixItHint::CreateReplacement(ReplaceRange, Replacement); 110 } 111 112 } // namespace modernize 113 } // namespace tidy 114 } // namespace clang 115