1 //===--- StringFindStartswithCheck.cc - clang-tidy---------------*- C++ -*-===// 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 "StringFindStartswithCheck.h" 10 11 #include "../utils/OptionsUtils.h" 12 #include "clang/AST/ASTContext.h" 13 #include "clang/ASTMatchers/ASTMatchers.h" 14 #include "clang/Frontend/CompilerInstance.h" 15 16 #include <cassert> 17 18 using namespace clang::ast_matchers; 19 20 namespace clang { 21 namespace tidy { 22 namespace abseil { 23 24 StringFindStartswithCheck::StringFindStartswithCheck(StringRef Name, 25 ClangTidyContext *Context) 26 : ClangTidyCheck(Name, Context), 27 StringLikeClasses(utils::options::parseStringList( 28 Options.get("StringLikeClasses", "::std::basic_string"))), 29 IncludeStyle(Options.getLocalOrGlobal("IncludeStyle", 30 utils::IncludeSorter::getMapping(), 31 utils::IncludeSorter::IS_LLVM)), 32 AbseilStringsMatchHeader( 33 Options.get("AbseilStringsMatchHeader", "absl/strings/match.h")) {} 34 35 void StringFindStartswithCheck::registerMatchers(MatchFinder *Finder) { 36 auto ZeroLiteral = integerLiteral(equals(0)); 37 auto StringClassMatcher = cxxRecordDecl(hasAnyName(SmallVector<StringRef, 4>( 38 StringLikeClasses.begin(), StringLikeClasses.end()))); 39 auto StringType = hasUnqualifiedDesugaredType( 40 recordType(hasDeclaration(StringClassMatcher))); 41 42 auto StringFind = cxxMemberCallExpr( 43 // .find()-call on a string... 44 callee(cxxMethodDecl(hasName("find"))), 45 on(hasType(StringType)), 46 // ... with some search expression ... 47 hasArgument(0, expr().bind("needle")), 48 // ... and either "0" as second argument or the default argument (also 0). 49 anyOf(hasArgument(1, ZeroLiteral), hasArgument(1, cxxDefaultArgExpr()))); 50 51 Finder->addMatcher( 52 // Match [=!]= with a zero on one side and a string.find on the other. 53 binaryOperator( 54 hasAnyOperatorName("==", "!="), 55 hasOperands(ignoringParenImpCasts(ZeroLiteral), 56 ignoringParenImpCasts(StringFind.bind("findexpr")))) 57 .bind("expr"), 58 this); 59 } 60 61 void StringFindStartswithCheck::check(const MatchFinder::MatchResult &Result) { 62 const ASTContext &Context = *Result.Context; 63 const SourceManager &Source = Context.getSourceManager(); 64 65 // Extract matching (sub)expressions 66 const auto *ComparisonExpr = Result.Nodes.getNodeAs<BinaryOperator>("expr"); 67 assert(ComparisonExpr != nullptr); 68 const auto *Needle = Result.Nodes.getNodeAs<Expr>("needle"); 69 assert(Needle != nullptr); 70 const Expr *Haystack = Result.Nodes.getNodeAs<CXXMemberCallExpr>("findexpr") 71 ->getImplicitObjectArgument(); 72 assert(Haystack != nullptr); 73 74 if (ComparisonExpr->getBeginLoc().isMacroID()) 75 return; 76 77 // Get the source code blocks (as characters) for both the string object 78 // and the search expression 79 const StringRef NeedleExprCode = Lexer::getSourceText( 80 CharSourceRange::getTokenRange(Needle->getSourceRange()), Source, 81 Context.getLangOpts()); 82 const StringRef HaystackExprCode = Lexer::getSourceText( 83 CharSourceRange::getTokenRange(Haystack->getSourceRange()), Source, 84 Context.getLangOpts()); 85 86 // Create the StartsWith string, negating if comparison was "!=". 87 bool Neg = ComparisonExpr->getOpcodeStr() == "!="; 88 StringRef StartswithStr; 89 if (Neg) { 90 StartswithStr = "!absl::StartsWith"; 91 } else { 92 StartswithStr = "absl::StartsWith"; 93 } 94 95 // Create the warning message and a FixIt hint replacing the original expr. 96 auto Diagnostic = 97 diag(ComparisonExpr->getBeginLoc(), 98 (StringRef("use ") + StartswithStr + " instead of find() " + 99 ComparisonExpr->getOpcodeStr() + " 0") 100 .str()); 101 102 Diagnostic << FixItHint::CreateReplacement( 103 ComparisonExpr->getSourceRange(), 104 (StartswithStr + "(" + HaystackExprCode + ", " + NeedleExprCode + ")") 105 .str()); 106 107 // Create a preprocessor #include FixIt hint (CreateIncludeInsertion checks 108 // whether this already exists). 109 Diagnostic << IncludeInserter->CreateIncludeInsertion( 110 Source.getFileID(ComparisonExpr->getBeginLoc()), AbseilStringsMatchHeader, 111 false); 112 } 113 114 void StringFindStartswithCheck::registerPPCallbacks( 115 const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) { 116 IncludeInserter = std::make_unique<utils::IncludeInserter>(SM, getLangOpts(), 117 IncludeStyle); 118 PP->addPPCallbacks(IncludeInserter->CreatePPCallbacks()); 119 } 120 121 void StringFindStartswithCheck::storeOptions( 122 ClangTidyOptions::OptionMap &Opts) { 123 Options.store(Opts, "StringLikeClasses", 124 utils::options::serializeStringList(StringLikeClasses)); 125 Options.store(Opts, "IncludeStyle", IncludeStyle, 126 utils::IncludeSorter::getMapping()); 127 Options.store(Opts, "AbseilStringsMatchHeader", AbseilStringsMatchHeader); 128 } 129 130 } // namespace abseil 131 } // namespace tidy 132 } // namespace clang 133