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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 {
#if !defined(PRODUCT)
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(ObjectPtr skip, ObjectPtr expected_parent)
: count_(0), size_(0), skip_(skip), expected_parent_(expected_parent) {}
virtual Direction VisitObject(ObjectGraph::StackIterator* it) {
ObjectPtr obj = it->Get();
if (obj == skip_) {
EXPECT(it->MoveToParent());
EXPECT_EQ(expected_parent_, it->Get());
return kBacktrack;
}
++count_;
size_ += obj->untag()->HeapSize();
return kProceed;
}
int count() const { return count_; }
int size() const { return size_; }
private:
int count_;
intptr_t size_;
ObjectPtr skip_;
ObjectPtr expected_parent_;
};
ISOLATE_UNIT_TEST_CASE(ObjectGraph) {
auto heap = thread->isolate_group()->heap();
// 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.ptr()->untag()->HeapSize();
intptr_t b_size = b.ptr()->untag()->HeapSize();
intptr_t c_size = c.ptr()->untag()->HeapSize();
intptr_t d_size = d.ptr()->untag()->HeapSize();
{
// No more allocation; raw pointers ahead.
GcSafepointOperationScope safepoint(thread);
ObjectPtr b_raw = b.ptr();
// 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.ptr());
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.ptr());
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()).length;
intptr_t empty_length =
graph.RetainingPath(&c, Object::empty_array()).length;
Array& path = Array::Handle(Array::New(1, Heap::kNew));
intptr_t one_length = graph.RetainingPath(&c, path).length;
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.
heap->CollectAllGarbage();
intptr_t length = graph.RetainingPath(&c, path).length;
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());
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());
Array& expected_a = Array::Handle();
expected_a ^= path.At(4);
EXPECT(expected_c.ptr() == c.ptr());
EXPECT(expected_b.ptr() == a.At(10));
EXPECT(expected_a.ptr() == a.ptr());
}
}
}
static void WeakHandleFinalizer(void* isolate_callback_data, void* peer) {}
ISOLATE_UNIT_TEST_CASE(RetainingPathGCRoot) {
Dart_PersistentHandle persistent_handle;
Dart_WeakPersistentHandle weak_persistent_handle;
Array& path = Array::Handle(Array::New(1, Heap::kNew));
ObjectGraph graph(thread);
Dart_Handle handle = Api::NewHandle(thread, path.ptr());
// GC root should be a local handle
auto result = graph.RetainingPath(&path, path);
EXPECT_STREQ(result.gc_root_type, "local handle");
// GC root should now be a weak persistent handle
{
TransitionVMToNative transition(thread);
weak_persistent_handle = Dart_NewWeakPersistentHandle(
handle, reinterpret_cast<void*>(0xdeadbeef), 128, WeakHandleFinalizer);
}
result = graph.RetainingPath(&path, path);
EXPECT_STREQ(result.gc_root_type, "weak persistent handle");
// GC root should now be a persistent handle
{
TransitionVMToNative transition(thread);
persistent_handle = Dart_NewPersistentHandle(handle);
}
result = graph.RetainingPath(&path, path);
EXPECT_STREQ(result.gc_root_type, "persistent handle");
// Delete the persistent handle. GC root should now be weak persistent handle
{
TransitionVMToNative transition(thread);
Dart_DeletePersistentHandle(persistent_handle);
persistent_handle = nullptr;
}
result = graph.RetainingPath(&path, path);
EXPECT_STREQ(result.gc_root_type, "weak persistent handle");
// Delete the weak persistent handle. GC root should now be local handle.
{
TransitionVMToNative transition(thread);
Dart_DeleteWeakPersistentHandle(weak_persistent_handle);
weak_persistent_handle = nullptr;
}
result = graph.RetainingPath(&path, path);
EXPECT_STREQ(result.gc_root_type, "local handle");
}
#endif // !defined(PRODUCT)
} // namespace dart