1 //===-- StdAllocatorConstCheck.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 "StdAllocatorConstCheck.h"
10 #include "clang/ASTMatchers/ASTMatchFinder.h"
11
12 using namespace clang::ast_matchers;
13
14 namespace clang::tidy::portability {
15
registerMatchers(MatchFinder * Finder)16 void StdAllocatorConstCheck::registerMatchers(MatchFinder *Finder) {
17 // Match std::allocator<const T>.
18 auto allocatorConst =
19 recordType(hasDeclaration(classTemplateSpecializationDecl(
20 hasName("::std::allocator"),
21 hasTemplateArgument(0, refersToType(qualType(isConstQualified()))))));
22
23 auto hasContainerName =
24 hasAnyName("::std::vector", "::std::deque", "::std::list",
25 "::std::multiset", "::std::set", "::std::unordered_multiset",
26 "::std::unordered_set", "::absl::flat_hash_set");
27
28 // Match `std::vector<const T> var;` and other common containers like deque,
29 // list, and absl::flat_hash_set. Containers like queue and stack use deque
30 // but do not directly use std::allocator as a template argument, so they
31 // aren't caught.
32 Finder->addMatcher(
33 typeLoc(
34 templateSpecializationTypeLoc(),
35 loc(hasUnqualifiedDesugaredType(anyOf(
36 recordType(hasDeclaration(classTemplateSpecializationDecl(
37 hasContainerName,
38 anyOf(
39 hasTemplateArgument(1, refersToType(allocatorConst)),
40 hasTemplateArgument(2, refersToType(allocatorConst)),
41 hasTemplateArgument(3, refersToType(allocatorConst)))))),
42 // Match std::vector<const dependent>
43 templateSpecializationType(
44 templateArgumentCountIs(1),
45 hasTemplateArgument(
46 0, refersToType(qualType(isConstQualified()))),
47 hasDeclaration(namedDecl(hasContainerName)))))))
48 .bind("type_loc"),
49 this);
50 }
51
check(const MatchFinder::MatchResult & Result)52 void StdAllocatorConstCheck::check(const MatchFinder::MatchResult &Result) {
53 const auto *T = Result.Nodes.getNodeAs<TypeLoc>("type_loc");
54 if (!T)
55 return;
56 // Exclude TypeLoc matches in STL headers.
57 if (isSystem(Result.Context->getSourceManager().getFileCharacteristic(
58 T->getBeginLoc())))
59 return;
60
61 diag(T->getBeginLoc(),
62 "container using std::allocator<const T> is a deprecated libc++ "
63 "extension; remove const for compatibility with other standard "
64 "libraries");
65 }
66
67 } // namespace clang::tidy::portability
68