1 //===--- AvoidCArraysCheck.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 "AvoidCArraysCheck.h" 10 #include "clang/AST/ASTContext.h" 11 #include "clang/ASTMatchers/ASTMatchFinder.h" 12 #include "clang/ASTMatchers/ASTMatchers.h" 13 14 using namespace clang::ast_matchers; 15 16 namespace clang::tidy::modernize { 17 18 namespace { 19 20 AST_MATCHER(clang::TypeLoc, hasValidBeginLoc) { 21 return Node.getBeginLoc().isValid(); 22 } 23 24 AST_MATCHER_P(clang::TypeLoc, hasType, 25 clang::ast_matchers::internal::Matcher<clang::Type>, 26 InnerMatcher) { 27 const clang::Type *TypeNode = Node.getTypePtr(); 28 return TypeNode != nullptr && 29 InnerMatcher.matches(*TypeNode, Finder, Builder); 30 } 31 32 AST_MATCHER(clang::RecordDecl, isExternCContext) { 33 return Node.isExternCContext(); 34 } 35 36 AST_MATCHER(clang::ParmVarDecl, isArgvOfMain) { 37 const clang::DeclContext *DC = Node.getDeclContext(); 38 const auto *FD = llvm::dyn_cast<clang::FunctionDecl>(DC); 39 return FD ? FD->isMain() : false; 40 } 41 42 } // namespace 43 44 AvoidCArraysCheck::AvoidCArraysCheck(StringRef Name, ClangTidyContext *Context) 45 : ClangTidyCheck(Name, Context), 46 AllowStringArrays(Options.get("AllowStringArrays", false)) {} 47 48 void AvoidCArraysCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) { 49 Options.store(Opts, "AllowStringArrays", AllowStringArrays); 50 } 51 52 void AvoidCArraysCheck::registerMatchers(MatchFinder *Finder) { 53 ast_matchers::internal::Matcher<TypeLoc> IgnoreStringArrayIfNeededMatcher = 54 anything(); 55 if (AllowStringArrays) 56 IgnoreStringArrayIfNeededMatcher = 57 unless(typeLoc(loc(hasCanonicalType(incompleteArrayType( 58 hasElementType(isAnyCharacter())))), 59 hasParent(varDecl(hasInitializer(stringLiteral()), 60 unless(parmVarDecl()))))); 61 62 Finder->addMatcher( 63 typeLoc(hasValidBeginLoc(), hasType(arrayType()), 64 optionally(hasParent(parmVarDecl().bind("param_decl"))), 65 unless(anyOf(hasParent(parmVarDecl(isArgvOfMain())), 66 hasParent(varDecl(isExternC())), 67 hasParent(fieldDecl( 68 hasParent(recordDecl(isExternCContext())))), 69 hasAncestor(functionDecl(isExternC())))), 70 std::move(IgnoreStringArrayIfNeededMatcher)) 71 .bind("typeloc"), 72 this); 73 } 74 75 void AvoidCArraysCheck::check(const MatchFinder::MatchResult &Result) { 76 const auto *ArrayType = Result.Nodes.getNodeAs<TypeLoc>("typeloc"); 77 const bool IsInParam = 78 Result.Nodes.getNodeAs<ParmVarDecl>("param_decl") != nullptr; 79 const bool IsVLA = ArrayType->getTypePtr()->isVariableArrayType(); 80 enum class RecommendType { Array, Vector, Span }; 81 llvm::SmallVector<const char *> RecommendTypes{}; 82 if (IsVLA) { 83 RecommendTypes.push_back("'std::vector'"); 84 } else if (ArrayType->getTypePtr()->isIncompleteArrayType() && IsInParam) { 85 // in function parameter, we also don't know the size of 86 // IncompleteArrayType. 87 if (Result.Context->getLangOpts().CPlusPlus20) 88 RecommendTypes.push_back("'std::span'"); 89 else { 90 RecommendTypes.push_back("'std::array'"); 91 RecommendTypes.push_back("'std::vector'"); 92 } 93 } else { 94 RecommendTypes.push_back("'std::array'"); 95 } 96 diag(ArrayType->getBeginLoc(), 97 "do not declare %select{C-style|C VLA}0 arrays, use %1 instead") 98 << IsVLA << llvm::join(RecommendTypes, " or "); 99 } 100 101 } // namespace clang::tidy::modernize 102