| Index: tools/clang/blink_gc_plugin/CheckGCRootsVisitor.cpp
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| diff --git a/tools/clang/blink_gc_plugin/CheckGCRootsVisitor.cpp b/tools/clang/blink_gc_plugin/CheckGCRootsVisitor.cpp
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| new file mode 100644
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| index 0000000000000000000000000000000000000000..ab2d2601bc3e527a39e144b1b0d6ccb022a4f7de
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| --- /dev/null
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| +++ b/tools/clang/blink_gc_plugin/CheckGCRootsVisitor.cpp
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| @@ -0,0 +1,53 @@
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| +// Copyright 2015 The Chromium Authors. All rights reserved.
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| +// Use of this source code is governed by a BSD-style license that can be
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| +// found in the LICENSE file.
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| +
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| +#include "CheckGCRootsVisitor.h"
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| +
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| +CheckGCRootsVisitor::CheckGCRootsVisitor() {
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| +}
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| +
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| +CheckGCRootsVisitor::Errors& CheckGCRootsVisitor::gc_roots() {
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| +  return gc_roots_;
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| +}
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| +
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| +bool CheckGCRootsVisitor::ContainsGCRoots(RecordInfo* info) {
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| +  for (RecordInfo::Fields::iterator it = info->GetFields().begin();
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| +       it != info->GetFields().end();
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| +       ++it) {
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| +    current_.push_back(&it->second);
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| +    it->second.edge()->Accept(this);
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| +    current_.pop_back();
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| +  }
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| +  return !gc_roots_.empty();
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| +}
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| +
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| +void CheckGCRootsVisitor::VisitValue(Value* edge) {
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| +  // TODO: what should we do to check unions?
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| +  if (edge->value()->record()->isUnion())
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| +    return;
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| +
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| +  // Prevent infinite regress for cyclic part objects.
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| +  if (visiting_set_.find(edge->value()) != visiting_set_.end())
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| +    return;
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| +
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| +  visiting_set_.insert(edge->value());
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| +  // If the value is a part object, then continue checking for roots.
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| +  for (Context::iterator it = context().begin();
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| +       it != context().end();
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| +       ++it) {
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| +    if (!(*it)->IsCollection())
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| +      return;
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| +  }
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| +  ContainsGCRoots(edge->value());
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| +  visiting_set_.erase(edge->value());
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| +}
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| +
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| +void CheckGCRootsVisitor::VisitPersistent(Persistent* edge) {
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| +  gc_roots_.push_back(current_);
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| +}
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| +
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| +void CheckGCRootsVisitor::AtCollection(Collection* edge) {
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| +  if (edge->is_root())
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| +    gc_roots_.push_back(current_);
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| +}
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| 
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