clang-tools-extra/clang-tidy/portability/StdAllocatorConstCheck.cpp

   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
  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
  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