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 
13 using namespace clang::ast_matchers;
14 
15 namespace {
16 
17 AST_MATCHER(clang::TypeLoc, hasValidBeginLoc) {
18   return Node.getBeginLoc().isValid();
19 }
20 
21 AST_MATCHER_P(clang::TypeLoc, hasType,
22               clang::ast_matchers::internal::Matcher<clang::Type>,
23               InnerMatcher) {
24   const clang::Type *TypeNode = Node.getTypePtr();
25   return TypeNode != nullptr &&
26          InnerMatcher.matches(*TypeNode, Finder, Builder);
27 }
28 
29 AST_MATCHER(clang::RecordDecl, isExternCContext) {
30   return Node.isExternCContext();
31 }
32 
33 AST_MATCHER(clang::ParmVarDecl, isArgvOfMain) {
34   const clang::DeclContext *DC = Node.getDeclContext();
35   const auto *FD = llvm::dyn_cast<clang::FunctionDecl>(DC);
36   return FD ? FD->isMain() : false;
37 }
38 
39 } // namespace
40 
41 namespace clang {
42 namespace tidy {
43 namespace modernize {
44 
45 void AvoidCArraysCheck::registerMatchers(MatchFinder *Finder) {
46   Finder->addMatcher(
47       typeLoc(hasValidBeginLoc(), hasType(arrayType()),
48               unless(anyOf(hasParent(parmVarDecl(isArgvOfMain())),
49                            hasParent(varDecl(isExternC())),
50                            hasParent(fieldDecl(
51                                hasParent(recordDecl(isExternCContext())))),
52                            hasAncestor(functionDecl(isExternC())))))
53           .bind("typeloc"),
54       this);
55 }
56 
57 void AvoidCArraysCheck::check(const MatchFinder::MatchResult &Result) {
58   const auto *ArrayType = Result.Nodes.getNodeAs<TypeLoc>("typeloc");
59 
60   diag(ArrayType->getBeginLoc(),
61        "do not declare %select{C-style|C VLA}0 arrays, use "
62        "%select{std::array<>|std::vector<>}0 instead")
63       << ArrayType->getTypePtr()->isVariableArrayType();
64 }
65 
66 } // namespace modernize
67 } // namespace tidy
68 } // namespace clang
69