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// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "CheckFinalizerVisitor.h"
using namespace clang;
namespace {
// Simple visitor to determine if the content of a field might be collected
// during finalization.
class MightBeCollectedVisitor : public EdgeVisitor {
public:
bool might_be_collected() const;
void VisitMember(Member* edge) override;
void VisitCollection(Collection* edge) override;
private:
bool might_be_collected_ = false;
};
bool MightBeCollectedVisitor::might_be_collected() const {
return might_be_collected_;
}
void MightBeCollectedVisitor::VisitMember(Member* edge) {
might_be_collected_ = true;
}
void MightBeCollectedVisitor::VisitCollection(Collection* edge) {
if (edge->on_heap()) {
might_be_collected_ = true;
} else {
edge->AcceptMembers(this);
}
}
} // namespace
CheckFinalizerVisitor::CheckFinalizerVisitor(RecordCache* cache)
: blocklist_context_(false),
cache_(cache) {
}
CheckFinalizerVisitor::Errors& CheckFinalizerVisitor::finalized_fields() {
return finalized_fields_;
}
bool CheckFinalizerVisitor::WalkUpFromCXXOperatorCallExpr(
CXXOperatorCallExpr* expr) {
// Only continue the walk-up if the operator is a blocklisted one.
switch (expr->getOperator()) {
case OO_Arrow:
case OO_Subscript:
this->WalkUpFromCallExpr(expr);
return true;
default:
return true;
}
}
bool CheckFinalizerVisitor::WalkUpFromCallExpr(CallExpr* expr) {
// We consider all non-operator calls to be blocklisted contexts.
bool prev_blocklist_context = blocklist_context_;
blocklist_context_ = true;
for (size_t i = 0; i < expr->getNumArgs(); ++i)
this->TraverseStmt(expr->getArg(i));
blocklist_context_ = prev_blocklist_context;
return true;
}
bool CheckFinalizerVisitor::VisitMemberExpr(MemberExpr* member) {
FieldDecl* field = dyn_cast<FieldDecl>(member->getMemberDecl());
if (!field)
return true;
RecordInfo* info = cache_->Lookup(field->getParent());
if (!info)
return true;
RecordInfo::Fields::iterator it = info->GetFields().find(field);
if (it == info->GetFields().end())
return true;
if (seen_members_.find(member) != seen_members_.end())
return true;
if (blocklist_context_ &&
MightBeCollected(&it->second)) {
finalized_fields_.push_back(
Error(member, &it->second));
seen_members_.insert(member);
}
return true;
}
bool CheckFinalizerVisitor::MightBeCollected(FieldPoint* point) {
MightBeCollectedVisitor visitor;
point->edge()->Accept(&visitor);
return visitor.might_be_collected();
}
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