128 lines
4.3 KiB
C++
128 lines
4.3 KiB
C++
//===--- MultipleInheritanceCheck.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 "MultipleInheritanceCheck.h"
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#include "clang/AST/ASTContext.h"
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#include "clang/ASTMatchers/ASTMatchFinder.h"
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using namespace clang;
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using namespace clang::ast_matchers;
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namespace clang {
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namespace tidy {
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namespace fuchsia {
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namespace {
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AST_MATCHER(CXXRecordDecl, hasBases) {
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if (Node.hasDefinition())
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return Node.getNumBases() > 0;
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return false;
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}
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} // namespace
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// Adds a node (by name) to the interface map, if it was not present in the map
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// previously.
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void MultipleInheritanceCheck::addNodeToInterfaceMap(const CXXRecordDecl *Node,
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bool IsInterface) {
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assert(Node->getIdentifier());
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StringRef Name = Node->getIdentifier()->getName();
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InterfaceMap.insert(std::make_pair(Name, IsInterface));
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}
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// Returns "true" if the boolean "isInterface" has been set to the
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// interface status of the current Node. Return "false" if the
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// interface status for the current node is not yet known.
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bool MultipleInheritanceCheck::getInterfaceStatus(const CXXRecordDecl *Node,
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bool &IsInterface) const {
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assert(Node->getIdentifier());
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StringRef Name = Node->getIdentifier()->getName();
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llvm::StringMapConstIterator<bool> Pair = InterfaceMap.find(Name);
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if (Pair == InterfaceMap.end())
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return false;
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IsInterface = Pair->second;
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return true;
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}
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bool MultipleInheritanceCheck::isCurrentClassInterface(
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const CXXRecordDecl *Node) const {
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// Interfaces should have no fields.
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if (!Node->field_empty()) return false;
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// Interfaces should have exclusively pure methods.
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return llvm::none_of(Node->methods(), [](const CXXMethodDecl *M) {
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return M->isUserProvided() && !M->isPure() && !M->isStatic();
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});
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}
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bool MultipleInheritanceCheck::isInterface(const CXXRecordDecl *Node) {
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if (!Node->getIdentifier())
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return false;
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// Short circuit the lookup if we have analyzed this record before.
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bool PreviousIsInterfaceResult;
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if (getInterfaceStatus(Node, PreviousIsInterfaceResult))
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return PreviousIsInterfaceResult;
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// To be an interface, all base classes must be interfaces as well.
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for (const auto &I : Node->bases()) {
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if (I.isVirtual()) continue;
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const auto *Ty = I.getType()->getAs<RecordType>();
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if (!Ty) continue;
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const RecordDecl *D = Ty->getDecl()->getDefinition();
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if (!D) continue;
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const auto *Base = cast<CXXRecordDecl>(D);
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if (!isInterface(Base)) {
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addNodeToInterfaceMap(Node, false);
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return false;
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}
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}
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bool CurrentClassIsInterface = isCurrentClassInterface(Node);
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addNodeToInterfaceMap(Node, CurrentClassIsInterface);
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return CurrentClassIsInterface;
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}
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void MultipleInheritanceCheck::registerMatchers(MatchFinder *Finder) {
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// Match declarations which have bases.
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Finder->addMatcher(
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cxxRecordDecl(allOf(hasBases(), isDefinition())).bind("decl"), this);
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}
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void MultipleInheritanceCheck::check(const MatchFinder::MatchResult &Result) {
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if (const auto *D = Result.Nodes.getNodeAs<CXXRecordDecl>("decl")) {
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// Check against map to see if if the class inherits from multiple
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// concrete classes
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unsigned NumConcrete = 0;
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for (const auto &I : D->bases()) {
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if (I.isVirtual()) continue;
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const auto *Ty = I.getType()->getAs<RecordType>();
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if (!Ty) continue;
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const auto *Base = cast<CXXRecordDecl>(Ty->getDecl()->getDefinition());
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if (!isInterface(Base)) NumConcrete++;
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}
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// Check virtual bases to see if there is more than one concrete
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// non-virtual base.
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for (const auto &V : D->vbases()) {
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const auto *Ty = V.getType()->getAs<RecordType>();
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if (!Ty) continue;
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const auto *Base = cast<CXXRecordDecl>(Ty->getDecl()->getDefinition());
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if (!isInterface(Base)) NumConcrete++;
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}
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if (NumConcrete > 1) {
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diag(D->getBeginLoc(), "inheriting multiple classes that aren't "
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"pure virtual is discouraged");
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}
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}
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}
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} // namespace fuchsia
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} // namespace tidy
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} // namespace clang
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