107 lines
3.6 KiB
C++
107 lines
3.6 KiB
C++
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//===--- ComparePointerToMemberVirtualFunctionCheck.cpp - clang-tidy ------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "ComparePointerToMemberVirtualFunctionCheck.h"
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#include "clang/AST/ASTContext.h"
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#include "clang/AST/ASTTypeTraits.h"
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#include "clang/AST/DeclCXX.h"
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#include "clang/AST/OperationKinds.h"
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#include "clang/AST/Type.h"
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#include "clang/ASTMatchers/ASTMatchFinder.h"
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#include "clang/ASTMatchers/ASTMatchers.h"
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#include "clang/ASTMatchers/ASTMatchersMacros.h"
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#include "clang/Basic/Diagnostic.h"
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#include "clang/Basic/DiagnosticIDs.h"
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#include "llvm/ADT/SmallVector.h"
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using namespace clang::ast_matchers;
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namespace clang::tidy::bugprone {
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namespace {
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AST_MATCHER(CXXMethodDecl, isVirtual) { return Node.isVirtual(); }
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static const char *const ErrorMsg =
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"comparing a pointer to member virtual function with other pointer is "
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"unspecified behavior, only compare it with a null-pointer constant for "
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"equality.";
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} // namespace
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void ComparePointerToMemberVirtualFunctionCheck::registerMatchers(
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MatchFinder *Finder) {
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auto DirectMemberVirtualFunctionPointer = unaryOperator(
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allOf(hasOperatorName("&"),
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hasUnaryOperand(declRefExpr(to(cxxMethodDecl(isVirtual()))))));
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auto IndirectMemberPointer =
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ignoringImpCasts(declRefExpr().bind("indirect_member_pointer"));
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Finder->addMatcher(
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binaryOperator(
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allOf(hasAnyOperatorName("==", "!="),
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hasEitherOperand(
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hasType(memberPointerType(pointee(functionType())))),
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anyOf(hasEitherOperand(DirectMemberVirtualFunctionPointer),
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hasEitherOperand(IndirectMemberPointer)),
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unless(hasEitherOperand(
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castExpr(hasCastKind(CK_NullToMemberPointer))))))
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.bind("binary_operator"),
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this);
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}
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void ComparePointerToMemberVirtualFunctionCheck::check(
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const MatchFinder::MatchResult &Result) {
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const auto *BO = Result.Nodes.getNodeAs<BinaryOperator>("binary_operator");
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const auto *DRE =
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Result.Nodes.getNodeAs<DeclRefExpr>("indirect_member_pointer");
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if (DRE == nullptr) {
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// compare with pointer to member virtual function.
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diag(BO->getOperatorLoc(), ErrorMsg);
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return;
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}
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// compare with variable which type is pointer to member function.
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llvm::SmallVector<SourceLocation, 12U> SameSignatureVirtualMethods{};
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const auto *MPT = cast<MemberPointerType>(DRE->getType().getCanonicalType());
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const Type *T = MPT->getClass();
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if (T == nullptr)
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return;
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const CXXRecordDecl *RD = T->getAsCXXRecordDecl();
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if (RD == nullptr)
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return;
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constexpr bool StopVisit = false;
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auto VisitSameSignatureVirtualMethods =
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[&](const CXXRecordDecl *CurrentRecordDecl) -> bool {
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bool Ret = !StopVisit;
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for (const auto *MD : CurrentRecordDecl->methods()) {
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if (MD->isVirtual() && MD->getType() == MPT->getPointeeType()) {
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SameSignatureVirtualMethods.push_back(MD->getBeginLoc());
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Ret = StopVisit;
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}
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}
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return Ret;
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};
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if (StopVisit != VisitSameSignatureVirtualMethods(RD)) {
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RD->forallBases(VisitSameSignatureVirtualMethods);
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}
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if (!SameSignatureVirtualMethods.empty()) {
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diag(BO->getOperatorLoc(), ErrorMsg);
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for (const auto Loc : SameSignatureVirtualMethods)
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diag(Loc, "potential member virtual function is declared here.",
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DiagnosticIDs::Note);
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}
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}
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} // namespace clang::tidy::bugprone
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