1 //===--- InitVariablesCheck.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 "InitVariablesCheck.h" 10 11 #include "../utils/LexerUtils.h" 12 #include "clang/AST/ASTContext.h" 13 #include "clang/AST/Type.h" 14 #include "clang/ASTMatchers/ASTMatchFinder.h" 15 #include "clang/Lex/Preprocessor.h" 16 #include <optional> 17 18 using namespace clang::ast_matchers; 19 20 namespace clang::tidy::cppcoreguidelines { 21 22 namespace { 23 AST_MATCHER(VarDecl, isLocalVarDecl) { return Node.isLocalVarDecl(); } 24 } // namespace 25 26 InitVariablesCheck::InitVariablesCheck(StringRef Name, 27 ClangTidyContext *Context) 28 : ClangTidyCheck(Name, Context), 29 IncludeInserter(Options.getLocalOrGlobal("IncludeStyle", 30 utils::IncludeSorter::IS_LLVM), 31 areDiagsSelfContained()), 32 MathHeader(Options.get("MathHeader", "<math.h>")) {} 33 34 void InitVariablesCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) { 35 Options.store(Opts, "IncludeStyle", IncludeInserter.getStyle()); 36 Options.store(Opts, "MathHeader", MathHeader); 37 } 38 39 void InitVariablesCheck::registerMatchers(MatchFinder *Finder) { 40 std::string BadDecl = "badDecl"; 41 Finder->addMatcher( 42 varDecl(unless(hasInitializer(anything())), unless(isInstantiated()), 43 isLocalVarDecl(), unless(isStaticLocal()), isDefinition(), 44 unless(hasParent(cxxCatchStmt())), 45 optionally(hasParent(declStmt(hasParent( 46 cxxForRangeStmt(hasLoopVariable(varDecl().bind(BadDecl))))))), 47 unless(equalsBoundNode(BadDecl))) 48 .bind("vardecl"), 49 this); 50 } 51 52 void InitVariablesCheck::registerPPCallbacks(const SourceManager &SM, 53 Preprocessor *PP, 54 Preprocessor *ModuleExpanderPP) { 55 IncludeInserter.registerPreprocessor(PP); 56 } 57 58 void InitVariablesCheck::check(const MatchFinder::MatchResult &Result) { 59 const auto *MatchedDecl = Result.Nodes.getNodeAs<VarDecl>("vardecl"); 60 const ASTContext &Context = *Result.Context; 61 const SourceManager &Source = Context.getSourceManager(); 62 63 // Clang diagnostic error may cause the variable to be an invalid int vardecl 64 if (MatchedDecl->isInvalidDecl()) 65 return; 66 67 // We want to warn about cases where the type name 68 // comes from a macro like this: 69 // 70 // TYPENAME_FROM_MACRO var; 71 // 72 // but not if the entire declaration comes from 73 // one: 74 // 75 // DEFINE_SOME_VARIABLE(); 76 // 77 // or if the definition comes from a macro like SWAP 78 // that uses an internal temporary variable. 79 // 80 // Thus check that the variable name does 81 // not come from a macro expansion. 82 if (MatchedDecl->getEndLoc().isMacroID()) 83 return; 84 85 QualType TypePtr = MatchedDecl->getType(); 86 std::optional<const char *> InitializationString; 87 bool AddMathInclude = false; 88 89 if (TypePtr->isEnumeralType()) 90 InitializationString = nullptr; 91 else if (TypePtr->isBooleanType()) 92 InitializationString = " = false"; 93 else if (TypePtr->isIntegerType()) 94 InitializationString = " = 0"; 95 else if (TypePtr->isFloatingType()) { 96 InitializationString = " = NAN"; 97 AddMathInclude = true; 98 } else if (TypePtr->isAnyPointerType()) { 99 if (getLangOpts().CPlusPlus11) 100 InitializationString = " = nullptr"; 101 else 102 InitializationString = " = NULL"; 103 } 104 105 if (InitializationString) { 106 auto Diagnostic = 107 diag(MatchedDecl->getLocation(), "variable %0 is not initialized") 108 << MatchedDecl; 109 if (*InitializationString != nullptr) 110 Diagnostic << FixItHint::CreateInsertion( 111 utils::lexer::findNextTerminator(MatchedDecl->getLocation(), 112 *Result.SourceManager, 113 Result.Context->getLangOpts()), 114 *InitializationString); 115 if (AddMathInclude) { 116 Diagnostic << IncludeInserter.createIncludeInsertion( 117 Source.getFileID(MatchedDecl->getBeginLoc()), MathHeader); 118 } 119 } 120 } 121 } // namespace clang::tidy::cppcoreguidelines 122