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
14using namespace clang::ast_matchers;
15
16namespace clang::tidy::modernize {
17
18namespace {
19
20AST_MATCHER(clang::TypeLoc, hasValidBeginLoc) {
21 return Node.getBeginLoc().isValid();
22}
23
24AST_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(Node: *TypeNode, Finder, Builder);
30}
31
32AST_MATCHER(clang::RecordDecl, isExternCContext) {
33 return Node.isExternCContext();
34}
35
36AST_MATCHER(clang::ParmVarDecl, isArgvOfMain) {
37 const clang::DeclContext *DC = Node.getDeclContext();
38 const auto *FD = llvm::dyn_cast<clang::FunctionDecl>(Val: DC);
39 return FD ? FD->isMain() : false;
40}
41
42} // namespace
43
44AvoidCArraysCheck::AvoidCArraysCheck(StringRef Name, ClangTidyContext *Context)
45 : ClangTidyCheck(Name, Context),
46 AllowStringArrays(Options.get(LocalName: "AllowStringArrays", Default: false)) {}
47
48void AvoidCArraysCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
49 Options.store(Options&: Opts, LocalName: "AllowStringArrays", Value: AllowStringArrays);
50}
51
52void AvoidCArraysCheck::registerMatchers(MatchFinder *Finder) {
53 ast_matchers::internal::Matcher<TypeLoc> IgnoreStringArrayIfNeededMatcher =
54 anything();
55 if (AllowStringArrays)
56 IgnoreStringArrayIfNeededMatcher =
57 unless(typeLoc(loc(InnerMatcher: hasCanonicalType(InnerMatcher: incompleteArrayType(
58 hasElementType(isAnyCharacter())))),
59 hasParent(varDecl(hasInitializer(InnerMatcher: stringLiteral()),
60 unless(parmVarDecl())))));
61
62 Finder->addMatcher(
63 NodeMatch: typeLoc(hasValidBeginLoc(), hasType(InnerMatcher: arrayType()),
64 optionally(hasParent(parmVarDecl().bind(ID: "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(ID: "typeloc"),
72 Action: this);
73}
74
75void AvoidCArraysCheck::check(const MatchFinder::MatchResult &Result) {
76 const auto *ArrayType = Result.Nodes.getNodeAs<TypeLoc>(ID: "typeloc");
77 const bool IsInParam =
78 Result.Nodes.getNodeAs<ParmVarDecl>(ID: "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(Elt: "'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(Elt: "'std::span'");
89 else {
90 RecommendTypes.push_back(Elt: "'std::array'");
91 RecommendTypes.push_back(Elt: "'std::vector'");
92 }
93 } else {
94 RecommendTypes.push_back(Elt: "'std::array'");
95 }
96 diag(Loc: ArrayType->getBeginLoc(),
97 Description: "do not declare %select{C-style|C VLA}0 arrays, use %1 instead")
98 << IsVLA << llvm::join(R&: RecommendTypes, Separator: " or ");
99}
100
101} // namespace clang::tidy::modernize
102

source code of clang-tools-extra/clang-tidy/modernize/AvoidCArraysCheck.cpp