Bisect clang

tools/clang/blink_gc_plugin/CheckFinalizerVisitor.cpp

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// 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:
+  explicit MightBeCollectedVisitor(bool is_eagerly_finalized);
+
+  bool might_be_collected() const;
+  bool as_eagerly_finalized() const;
+
+  void VisitMember(Member* edge) override;
+  void VisitCollection(Collection* edge) override;
+
+ private:
+  bool might_be_collected_;
+  bool is_eagerly_finalized_;
+  bool as_eagerly_finalized_;
+};
+
+MightBeCollectedVisitor::MightBeCollectedVisitor(bool is_eagerly_finalized)
+    : might_be_collected_(false),
+      is_eagerly_finalized_(is_eagerly_finalized),
+      as_eagerly_finalized_(false) {
+}
+
+bool MightBeCollectedVisitor::might_be_collected() const {
+  return might_be_collected_;
+}
+
+bool MightBeCollectedVisitor::as_eagerly_finalized() const {
+  return as_eagerly_finalized_;
+}
+
+void MightBeCollectedVisitor::VisitMember(Member* edge) {
+  if (is_eagerly_finalized_) {
+    if (edge->ptr()->IsValue()) {
+      Value* member = static_cast<Value*>(edge->ptr());
+      if (member->value()->IsEagerlyFinalized()) {
+        might_be_collected_ = true;
+        as_eagerly_finalized_ = true;
+      }
+    }
+    return;
+  }
+  might_be_collected_ = true;
+}
+
+void MightBeCollectedVisitor::VisitCollection(Collection* edge) {
+  if (edge->on_heap() && !is_eagerly_finalized_) {
+    might_be_collected_ = !edge->is_root();
+  } else {
+    edge->AcceptMembers(this);
+  }
+}
+
+}  // namespace
+
+CheckFinalizerVisitor::CheckFinalizerVisitor(RecordCache* cache,
+                                             bool is_eagerly_finalized)
+    : blacklist_context_(false),
+      cache_(cache),
+      is_eagerly_finalized_(is_eagerly_finalized) {
+}
+
+CheckFinalizerVisitor::Errors& CheckFinalizerVisitor::finalized_fields() {
+  return finalized_fields_;
+}
+
+bool CheckFinalizerVisitor::WalkUpFromCXXOperatorCallExpr(
+    CXXOperatorCallExpr* expr) {
+  // Only continue the walk-up if the operator is a blacklisted 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 blacklisted contexts.
+  bool prev_blacklist_context = blacklist_context_;
+  blacklist_context_ = true;
+  for (size_t i = 0; i < expr->getNumArgs(); ++i)
+    this->TraverseStmt(expr->getArg(i));
+  blacklist_context_ = prev_blacklist_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;
+
+  bool as_eagerly_finalized = false;
+  if (blacklist_context_ &&
+      MightBeCollected(&it->second, &as_eagerly_finalized)) {
+    finalized_fields_.push_back(
+        Error(member, as_eagerly_finalized, &it->second));
+    seen_members_.insert(member);
+  }
+  return true;
+}
+
+bool CheckFinalizerVisitor::MightBeCollected(FieldPoint* point,
+                                             bool* as_eagerly_finalized) {
+  MightBeCollectedVisitor visitor(is_eagerly_finalized_);
+  point->edge()->Accept(&visitor);
+  *as_eagerly_finalized = visitor.as_eagerly_finalized();
+  return visitor.might_be_collected();
+}