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// Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#include "vm/object_graph.h"
#include "platform/assert.h"
#include "vm/unit_test.h"
namespace dart {
class CounterVisitor : public ObjectGraph::Visitor {
public:
// Records the number of objects and total size visited, excluding 'skip'
// and any objects only reachable through 'skip'.
CounterVisitor(RawObject* skip, RawObject* expected_parent)
: count_(0), size_(0), skip_(skip), expected_parent_(expected_parent) {}
virtual Direction VisitObject(ObjectGraph::StackIterator* it) {
RawObject* obj = it->Get();
if (obj == skip_) {
EXPECT(it->MoveToParent());
EXPECT_EQ(expected_parent_, it->Get());
return kBacktrack;
}
++count_;
size_ += obj->HeapSize();
return kProceed;
}
int count() const { return count_; }
int size() const { return size_; }
private:
int count_;
intptr_t size_;
RawObject* skip_;
RawObject* expected_parent_;
};
ISOLATE_UNIT_TEST_CASE(ObjectGraph) {
Isolate* isolate = thread->isolate();
// Create a simple object graph with objects a, b, c, d:
// a+->b+->c
// +   +
// |   v
// +-->d
Array& a = Array::Handle(Array::New(12, Heap::kNew));
Array& b = Array::Handle(Array::New(2, Heap::kOld));
Array& c = Array::Handle(Array::New(0, Heap::kOld));
Array& d = Array::Handle(Array::New(0, Heap::kOld));
a.SetAt(10, b);
b.SetAt(0, c);
b.SetAt(1, d);
a.SetAt(11, d);
intptr_t a_size = a.raw()->HeapSize();
intptr_t b_size = b.raw()->HeapSize();
intptr_t c_size = c.raw()->HeapSize();
intptr_t d_size = d.raw()->HeapSize();
{
// No more allocation; raw pointers ahead.
SafepointOperationScope safepoint(thread);
RawObject* b_raw = b.raw();
// Clear handles to cut unintended retained paths.
b = Array::null();
c = Array::null();
d = Array::null();
ObjectGraph graph(thread);
{
HeapIterationScope iteration_scope(thread, true);
{
// Compare count and size when 'b' is/isn't skipped.
CounterVisitor with(Object::null(), Object::null());
graph.IterateObjectsFrom(a, &with);
CounterVisitor without(b_raw, a.raw());
graph.IterateObjectsFrom(a, &without);
// Only 'b' and 'c' were cut off.
EXPECT_EQ(2, with.count() - without.count());
EXPECT_EQ(b_size + c_size, with.size() - without.size());
}
{
// Like above, but iterate over the entire isolate. The counts and sizes
// are thus larger, but the difference should still be just 'b' and 'c'.
CounterVisitor with(Object::null(), Object::null());
graph.IterateObjects(&with);
CounterVisitor without(b_raw, a.raw());
graph.IterateObjects(&without);
EXPECT_EQ(2, with.count() - without.count());
EXPECT_EQ(b_size + c_size, with.size() - without.size());
}
}
EXPECT_EQ(a_size + b_size + c_size + d_size,
graph.SizeRetainedByInstance(a));
}
{
// Get hold of c again.
b ^= a.At(10);
c ^= b.At(0);
b = Array::null();
ObjectGraph graph(thread);
// A retaining path should end like this: c <- b <- a <- ...
{
HANDLESCOPE(thread);
// Test null, empty, and length 1 array.
intptr_t null_length = graph.RetainingPath(&c, Object::null_array());
intptr_t empty_length = graph.RetainingPath(&c, Object::empty_array());
Array& path = Array::Handle(Array::New(1, Heap::kNew));
intptr_t one_length = graph.RetainingPath(&c, path);
EXPECT_EQ(null_length, empty_length);
EXPECT_EQ(null_length, one_length);
EXPECT_LE(3, null_length);
}
{
HANDLESCOPE(thread);
Array& path = Array::Handle(Array::New(6, Heap::kNew));
// Trigger a full GC to increase probability of concurrent tasks.
isolate->heap()->CollectAllGarbage();
intptr_t length = graph.RetainingPath(&c, path);
EXPECT_LE(3, length);
Array& expected_c = Array::Handle();
expected_c ^= path.At(0);
// c is the first element in b.
Smi& offset_from_parent = Smi::Handle();
offset_from_parent ^= path.At(1);
EXPECT_EQ(Array::element_offset(0),
offset_from_parent.Value() * kWordSize);
Array& expected_b = Array::Handle();
expected_b ^= path.At(2);
// b is the element with index 10 in a.
offset_from_parent ^= path.At(3);
EXPECT_EQ(Array::element_offset(10),
offset_from_parent.Value() * kWordSize);
Array& expected_a = Array::Handle();
expected_a ^= path.At(4);
EXPECT(expected_c.raw() == c.raw());
EXPECT(expected_b.raw() == a.At(10));
EXPECT(expected_a.raw() == a.raw());
}
}
}
} // namespace dart