1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181
|
//===--- CrtpConstructorAccessibilityCheck.cpp - clang-tidy ---------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "CrtpConstructorAccessibilityCheck.h"
#include "../utils/LexerUtils.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
using namespace clang::ast_matchers;
namespace clang::tidy::bugprone {
static bool hasPrivateConstructor(const CXXRecordDecl *RD) {
return llvm::any_of(RD->ctors(), [](const CXXConstructorDecl *Ctor) {
return Ctor->getAccess() == AS_private;
});
}
static bool isDerivedParameterBefriended(const CXXRecordDecl *CRTP,
const NamedDecl *Param) {
return llvm::any_of(CRTP->friends(), [&](const FriendDecl *Friend) {
const TypeSourceInfo *const FriendType = Friend->getFriendType();
if (!FriendType) {
return false;
}
const auto *const TTPT =
dyn_cast<TemplateTypeParmType>(FriendType->getType());
return TTPT && TTPT->getDecl() == Param;
});
}
static bool isDerivedClassBefriended(const CXXRecordDecl *CRTP,
const CXXRecordDecl *Derived) {
return llvm::any_of(CRTP->friends(), [&](const FriendDecl *Friend) {
const TypeSourceInfo *const FriendType = Friend->getFriendType();
if (!FriendType) {
return false;
}
return FriendType->getType()->getAsCXXRecordDecl() == Derived;
});
}
static const NamedDecl *
getDerivedParameter(const ClassTemplateSpecializationDecl *CRTP,
const CXXRecordDecl *Derived) {
size_t Idx = 0;
const bool AnyOf = llvm::any_of(
CRTP->getTemplateArgs().asArray(), [&](const TemplateArgument &Arg) {
++Idx;
return Arg.getKind() == TemplateArgument::Type &&
Arg.getAsType()->getAsCXXRecordDecl() == Derived;
});
return AnyOf ? CRTP->getSpecializedTemplate()
->getTemplateParameters()
->getParam(Idx - 1)
: nullptr;
}
static std::vector<FixItHint>
hintMakeCtorPrivate(const CXXConstructorDecl *Ctor,
const std::string &OriginalAccess) {
std::vector<FixItHint> Hints;
Hints.emplace_back(FixItHint::CreateInsertion(
Ctor->getBeginLoc().getLocWithOffset(-1), "private:\n"));
const ASTContext &ASTCtx = Ctor->getASTContext();
const SourceLocation CtorEndLoc =
Ctor->isExplicitlyDefaulted()
? utils::lexer::findNextTerminator(Ctor->getEndLoc(),
ASTCtx.getSourceManager(),
ASTCtx.getLangOpts())
: Ctor->getEndLoc();
Hints.emplace_back(FixItHint::CreateInsertion(
CtorEndLoc.getLocWithOffset(1), '\n' + OriginalAccess + ':' + '\n'));
return Hints;
}
void CrtpConstructorAccessibilityCheck::registerMatchers(MatchFinder *Finder) {
Finder->addMatcher(
classTemplateSpecializationDecl(
decl().bind("crtp"),
hasAnyTemplateArgument(refersToType(recordType(hasDeclaration(
cxxRecordDecl(
isDerivedFrom(cxxRecordDecl(equalsBoundNode("crtp"))))
.bind("derived")))))),
this);
}
void CrtpConstructorAccessibilityCheck::check(
const MatchFinder::MatchResult &Result) {
const auto *CRTPInstantiation =
Result.Nodes.getNodeAs<ClassTemplateSpecializationDecl>("crtp");
const auto *DerivedRecord = Result.Nodes.getNodeAs<CXXRecordDecl>("derived");
const CXXRecordDecl *CRTPDeclaration =
CRTPInstantiation->getSpecializedTemplate()->getTemplatedDecl();
if (!CRTPDeclaration->hasDefinition()) {
return;
}
const auto *DerivedTemplateParameter =
getDerivedParameter(CRTPInstantiation, DerivedRecord);
assert(DerivedTemplateParameter &&
"No template parameter corresponds to the derived class of the CRTP.");
bool NeedsFriend = !isDerivedParameterBefriended(CRTPDeclaration,
DerivedTemplateParameter) &&
!isDerivedClassBefriended(CRTPDeclaration, DerivedRecord);
const FixItHint HintFriend = FixItHint::CreateInsertion(
CRTPDeclaration->getBraceRange().getEnd(),
"friend " + DerivedTemplateParameter->getNameAsString() + ';' + '\n');
if (hasPrivateConstructor(CRTPDeclaration) && NeedsFriend) {
diag(CRTPDeclaration->getLocation(),
"the CRTP cannot be constructed from the derived class; consider "
"declaring the derived class as friend")
<< HintFriend;
}
auto WithFriendHintIfNeeded =
[&](const DiagnosticBuilder &Diag,
bool NeedsFriend) -> const DiagnosticBuilder & {
if (NeedsFriend)
Diag << HintFriend;
return Diag;
};
if (!CRTPDeclaration->hasUserDeclaredConstructor()) {
const bool IsStruct = CRTPDeclaration->isStruct();
WithFriendHintIfNeeded(
diag(CRTPDeclaration->getLocation(),
"the implicit default constructor of the CRTP is publicly "
"accessible; consider making it private%select{| and declaring "
"the derived class as friend}0")
<< NeedsFriend
<< FixItHint::CreateInsertion(
CRTPDeclaration->getBraceRange().getBegin().getLocWithOffset(
1),
(IsStruct ? "\nprivate:\n" : "\n") +
CRTPDeclaration->getNameAsString() + "() = default;\n" +
(IsStruct ? "public:\n" : "")),
NeedsFriend);
}
for (auto &&Ctor : CRTPDeclaration->ctors()) {
if (Ctor->getAccess() == AS_private)
continue;
const bool IsPublic = Ctor->getAccess() == AS_public;
const std::string Access = IsPublic ? "public" : "protected";
WithFriendHintIfNeeded(
diag(Ctor->getLocation(),
"%0 contructor allows the CRTP to be %select{inherited "
"from|constructed}1 as a regular template class; consider making "
"it private%select{| and declaring the derived class as friend}2")
<< Access << IsPublic << NeedsFriend
<< hintMakeCtorPrivate(Ctor, Access),
NeedsFriend);
}
}
bool CrtpConstructorAccessibilityCheck::isLanguageVersionSupported(
const LangOptions &LangOpts) const {
return LangOpts.CPlusPlus11;
}
} // namespace clang::tidy::bugprone
|