Revision: 20710
Author: [email protected]
Date: Mon Apr 14 08:58:00 2014 UTC
Log: Some tests and simplified TransitionArray copying
Tests for verifying that we deal correctly with shrinking transition
arrays while allocating a copy of one.
Also, we can rely on a transition array only shrinking and not
disappearing during gc while copying one.
[email protected]
Review URL: https://codereview.chromium.org/232883003
http://code.google.com/p/v8/source/detail?r=20710
Modified:
/branches/bleeding_edge/src/objects.cc
/branches/bleeding_edge/src/transitions.cc
/branches/bleeding_edge/test/cctest/test-heap.cc
=======================================
--- /branches/bleeding_edge/src/objects.cc Mon Apr 14 08:24:15 2014 UTC
+++ /branches/bleeding_edge/src/objects.cc Mon Apr 14 08:58:00 2014 UTC
@@ -9474,11 +9474,16 @@
}
}
+ // Note that we never eliminate a transition array, though we might
right-trim
+ // such that number_of_transitions() == 0. If this assumption changes,
+ // TransitionArray::CopyInsert() will need to deal with the case that a
+ // transition array disappeared during GC.
int trim = t->number_of_transitions() - transition_index;
if (trim > 0) {
RightTrimFixedArray<Heap::FROM_GC>(heap, t, t->IsSimpleTransition()
? trim : trim * TransitionArray::kTransitionSize);
}
+ ASSERT(HasTransitionArray());
}
=======================================
--- /branches/bleeding_edge/src/transitions.cc Fri Apr 11 14:25:00 2014 UTC
+++ /branches/bleeding_edge/src/transitions.cc Mon Apr 14 08:58:00 2014 UTC
@@ -124,26 +124,11 @@
Handle<TransitionArray> result = Allocate(map->GetIsolate(), new_size);
- // The map's transition array may have disappeared or grown smaller
during
- // the allocation above as it was weakly traversed. Trim the result copy
if
- // needed, and recompute variables.
+ // The map's transition array may grown smaller during the allocation
above as
+ // it was weakly traversed, though it is guaranteed not to disappear.
Trim the
+ // result copy if needed, and recompute variables.
+ ASSERT(map->HasTransitionArray());
DisallowHeapAllocation no_gc;
- if (!map->HasTransitionArray()) {
- if (flag == SIMPLE_TRANSITION) {
- ASSERT(result->length() >= kSimpleTransitionSize);
- result->Shrink(kSimpleTransitionSize);
- result->set(kSimpleTransitionTarget, *target);
- } else {
- ASSERT(result->length() >= ToKeyIndex(1));
- result->Shrink(ToKeyIndex(1));
- result->set(kPrototypeTransitionsIndex, Smi::FromInt(0));
- result->NoIncrementalWriteBarrierSet(0, *name, *target);
- }
- result->set_back_pointer_storage(map->GetBackPointer());
-
- return result;
- }
-
TransitionArray* array = map->transitions();
if (array->number_of_transitions() != number_of_transitions) {
ASSERT(array->number_of_transitions() < number_of_transitions);
=======================================
--- /branches/bleeding_edge/test/cctest/test-heap.cc Fri Apr 11 12:47:34
2014 UTC
+++ /branches/bleeding_edge/test/cctest/test-heap.cc Mon Apr 14 08:58:00
2014 UTC
@@ -2669,6 +2669,145 @@
CompileRun("%DebugPrint(root);");
CHECK_EQ(1, transitions_after);
}
+
+
+#ifdef DEBUG
+static void AddTransitions(int transitions_count) {
+ AlwaysAllocateScope always_allocate(CcTest::i_isolate());
+ for (int i = 0; i < transitions_count; i++) {
+ EmbeddedVector<char, 64> buffer;
+ OS::SNPrintF(buffer, "var o = new Object; o.prop%d = %d;", i, i);
+ CompileRun(buffer.start());
+ }
+}
+
+
+static Handle<JSObject> GetByName(const char* name) {
+ return v8::Utils::OpenHandle(
+ *v8::Handle<v8::Object>::Cast(
+ CcTest::global()->Get(v8_str(name))));
+}
+
+
+static void AddPropertyTo(
+ int gc_count, Handle<JSObject> object, const char* property_name) {
+ Isolate* isolate = CcTest::i_isolate();
+ Factory* factory = isolate->factory();
+ Handle<String> prop_name = factory->InternalizeUtf8String(property_name);
+ Handle<Smi> twenty_three(Smi::FromInt(23), isolate);
+ i::FLAG_gc_interval = gc_count;
+ i::FLAG_gc_global = true;
+ CcTest::heap()->set_allocation_timeout(gc_count);
+ JSReceiver::SetProperty(
+ object, prop_name, twenty_three, NONE, SLOPPY).Check();
+}
+
+
+TEST(TransitionArrayShrinksDuringAllocToZero) {
+ i::FLAG_stress_compaction = false;
+ i::FLAG_allow_natives_syntax = true;
+ CcTest::InitializeVM();
+ v8::HandleScope scope(CcTest::isolate());
+ static const int transitions_count = 10;
+ AddTransitions(transitions_count);
+ CompileRun("var root = new Object;");
+ Handle<JSObject> root = GetByName("root");
+
+ // Count number of live transitions before marking.
+ int transitions_before = CountMapTransitions(root->map());
+ CHECK_EQ(transitions_count, transitions_before);
+
+ // Get rid of o
+ CompileRun("o = new Object;"
+ "root = new Object");
+ root = GetByName("root");
+ AddPropertyTo(2, root, "funny");
+
+ // Count number of live transitions after marking. Note that one
transition
+ // is left, because 'o' still holds an instance of one transition target.
+ int transitions_after = CountMapTransitions(
+ Map::cast(root->map()->GetBackPointer()));
+ CHECK_EQ(1, transitions_after);
+}
+
+
+TEST(TransitionArrayShrinksDuringAllocToOne) {
+ i::FLAG_stress_compaction = false;
+ i::FLAG_allow_natives_syntax = true;
+ CcTest::InitializeVM();
+ v8::HandleScope scope(CcTest::isolate());
+ static const int transitions_count = 10;
+ AddTransitions(transitions_count);
+ CompileRun("var root = new Object;");
+ Handle<JSObject> root = GetByName("root");
+
+ // Count number of live transitions before marking.
+ int transitions_before = CountMapTransitions(root->map());
+ CHECK_EQ(transitions_count, transitions_before);
+
+ root = GetByName("root");
+ AddPropertyTo(2, root, "funny");
+
+ // Count number of live transitions after marking. Note that one
transition
+ // is left, because 'o' still holds an instance of one transition target.
+ int transitions_after = CountMapTransitions(
+ Map::cast(root->map()->GetBackPointer()));
+ CHECK_EQ(2, transitions_after);
+}
+
+
+TEST(TransitionArrayShrinksDuringAllocToOnePropertyFound) {
+ i::FLAG_stress_compaction = false;
+ i::FLAG_allow_natives_syntax = true;
+ CcTest::InitializeVM();
+ v8::HandleScope scope(CcTest::isolate());
+ static const int transitions_count = 10;
+ AddTransitions(transitions_count);
+ CompileRun("var root = new Object;");
+ Handle<JSObject> root = GetByName("root");
+
+ // Count number of live transitions before marking.
+ int transitions_before = CountMapTransitions(root->map());
+ CHECK_EQ(transitions_count, transitions_before);
+
+ root = GetByName("root");
+ AddPropertyTo(0, root, "prop9");
+
+ // Count number of live transitions after marking. Note that one
transition
+ // is left, because 'o' still holds an instance of one transition target.
+ int transitions_after = CountMapTransitions(
+ Map::cast(root->map()->GetBackPointer()));
+ CHECK_EQ(1, transitions_after);
+}
+
+
+TEST(TransitionArraySimpleToFull) {
+ i::FLAG_stress_compaction = false;
+ i::FLAG_allow_natives_syntax = true;
+ CcTest::InitializeVM();
+ v8::HandleScope scope(CcTest::isolate());
+ static const int transitions_count = 1;
+ AddTransitions(transitions_count);
+ CompileRun("var root = new Object;");
+ Handle<JSObject> root = GetByName("root");
+
+ // Count number of live transitions before marking.
+ int transitions_before = CountMapTransitions(root->map());
+ CHECK_EQ(transitions_count, transitions_before);
+
+ CompileRun("o = new Object;"
+ "root = new Object");
+ root = GetByName("root");
+ ASSERT(root->map()->transitions()->IsSimpleTransition());
+ AddPropertyTo(2, root, "happy");
+
+ // Count number of live transitions after marking. Note that one
transition
+ // is left, because 'o' still holds an instance of one transition target.
+ int transitions_after = CountMapTransitions(
+ Map::cast(root->map()->GetBackPointer()));
+ CHECK_EQ(1, transitions_after);
+}
+#endif // DEBUG
TEST(Regress2143a) {
--
--
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