Reviewers: Michael Starzinger,
Message:
PTAL.
Description:
Moving the WhitenessWitness back to DescriptorArray.
TransitionArrays never allocate while being created.
Please review this at https://chromiumcodereview.appspot.com/10908237/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files:
M src/objects-inl.h
M src/objects.h
M src/objects.cc
M src/transitions-inl.h
M src/transitions.h
M src/transitions.cc
Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index
65a96612b76b1e321767d05515cfa4401cee445f..36d0b6c15c5be65ccea2b5d09a3894308288fc50
100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -2167,14 +2167,14 @@ void DescriptorArray::SwapSortedKeys(int first, int
second) {
}
-FixedArray::WhitenessWitness::WhitenessWitness(FixedArray* array)
+DescriptorArray::WhitenessWitness::WhitenessWitness(FixedArray* array)
: marking_(array->GetHeap()->incremental_marking()) {
marking_->EnterNoMarkingScope();
ASSERT(Marking::Color(array) == Marking::WHITE_OBJECT);
}
-FixedArray::WhitenessWitness::~WhitenessWitness() {
+DescriptorArray::WhitenessWitness::~WhitenessWitness() {
marking_->LeaveNoMarkingScope();
}
Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index
a7d6faa5e6ca06a8c0e53662dd58bfa1a22a27f1..a5339438add817cf02241fd379846d45d99f6cbb
100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -5008,7 +5008,7 @@ MaybeObject* Map::ShareDescriptor(Descriptor*
descriptor) {
DescriptorArray* new_descriptors;
MaybeObject* maybe_descriptors = DescriptorArray::Allocate(old_size + 1);
if (!maybe_descriptors->To(&new_descriptors)) return maybe_descriptors;
- FixedArray::WhitenessWitness witness(new_descriptors);
+ DescriptorArray::WhitenessWitness witness(new_descriptors);
for (int i = 0; i < old_size; ++i) {
new_descriptors->CopyFrom(i, descriptors, i, witness);
@@ -5198,7 +5198,7 @@ MaybeObject* Map::CopyAddDescriptor(Descriptor*
descriptor,
MaybeObject* maybe_descriptors = DescriptorArray::Allocate(old_size + 1);
if (!maybe_descriptors->To(&new_descriptors)) return maybe_descriptors;
- FixedArray::WhitenessWitness witness(new_descriptors);
+ DescriptorArray::WhitenessWitness witness(new_descriptors);
// Copy the descriptors, inserting a descriptor.
for (int i = 0; i < old_size; ++i) {
@@ -12897,7 +12897,7 @@ MaybeObject*
StringDictionary::TransformPropertiesToFastFor(
return maybe_descriptors;
}
- FixedArray::WhitenessWitness witness(descriptors);
+ DescriptorArray::WhitenessWitness witness(descriptors);
int number_of_allocated_fields =
number_of_fields + unused_property_fields - inobject_props;
Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index
e1f1d3bad4df0aaf18bb5379caaf1a5c655d5f5f..76503e7975f85cc7d6e4af6cddfd960914337dfc
100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -2375,23 +2375,6 @@ class FixedArray: public FixedArrayBase {
}
};
- // WhitenessWitness is used to prove that a descriptor array is white
- // (unmarked), so incremental write barriers can be skipped because the
- // marking invariant cannot be broken and slots pointing into evacuation
- // candidates will be discovered when the object is scanned. A witness is
- // always stack-allocated right after creating an array. By allocating a
- // witness, incremental marking is globally disabled. The witness is then
- // passed along wherever needed to statically prove that the array is
known to
- // be white.
- class WhitenessWitness {
- public:
- inline explicit WhitenessWitness(FixedArray* array);
- inline ~WhitenessWitness();
-
- private:
- IncrementalMarking* marking_;
- };
-
protected:
// Set operation on FixedArray without using write barriers. Can
// only be used for storing old space objects or smis.
@@ -2475,6 +2458,23 @@ class FixedDoubleArray: public FixedArrayBase {
// [length() - kDescriptorSize]: last key
class DescriptorArray: public FixedArray {
public:
+ // WhitenessWitness is used to prove that a descriptor array is white
+ // (unmarked), so incremental write barriers can be skipped because the
+ // marking invariant cannot be broken and slots pointing into evacuation
+ // candidates will be discovered when the object is scanned. A witness is
+ // always stack-allocated right after creating an array. By allocating a
+ // witness, incremental marking is globally disabled. The witness is then
+ // passed along wherever needed to statically prove that the array is
known to
+ // be white.
+ class WhitenessWitness {
+ public:
+ inline explicit WhitenessWitness(FixedArray* array);
+ inline ~WhitenessWitness();
+
+ private:
+ IncrementalMarking* marking_;
+ };
+
// Returns true for both shared empty_descriptor_array and for smis,
which the
// map uses to encode additional bit fields when the descriptor array is
not
// yet used.
Index: src/transitions-inl.h
diff --git a/src/transitions-inl.h b/src/transitions-inl.h
index
fd97ad25ab57d3946245b9e40c618083e2cbd1c4..517e6423ad24ad22d15a613e1d947f22da3245cf
100644
--- a/src/transitions-inl.h
+++ b/src/transitions-inl.h
@@ -200,16 +200,9 @@ int TransitionArray::Search(String* name) {
}
-void TransitionArray::Set(int transition_number,
- String* key,
- Map* target,
- const WhitenessWitness&) {
- NoIncrementalWriteBarrierSet(this,
- ToKeyIndex(transition_number),
- key);
- NoIncrementalWriteBarrierSet(this,
- ToTargetIndex(transition_number),
- target);
+void TransitionArray::Set(int transition_number, String* key, Map* target)
{
+ NoIncrementalWriteBarrierSet(this, ToKeyIndex(transition_number), key);
+ NoIncrementalWriteBarrierSet(this, ToTargetIndex(transition_number),
target);
}
Index: src/transitions.cc
diff --git a/src/transitions.cc b/src/transitions.cc
index
0ea58c7d5f530164611c5292658ac6a91d275bc0..9955022a3ee205f2bbfbad70a5e195671535c48a
100644
--- a/src/transitions.cc
+++ b/src/transitions.cc
@@ -60,12 +60,10 @@ MaybeObject* TransitionArray::Allocate(int
number_of_transitions,
void TransitionArray::CopyFrom(TransitionArray* origin,
int origin_transition,
- int target_transition,
- const WhitenessWitness& witness) {
+ int target_transition) {
Set(target_transition,
origin->GetKey(origin_transition),
- origin->GetTarget(origin_transition),
- witness);
+ origin->GetTarget(origin_transition));
}
@@ -84,9 +82,7 @@ MaybeObject* TransitionArray::NewWith(
MaybeObject* maybe_array = TransitionArray::Allocate(1,
descriptors_pointer);
if (!maybe_array->To(&result)) return maybe_array;
- FixedArray::WhitenessWitness witness(result);
-
- result->Set(0, name, target, witness);
+ result->Set(0, name, target);
result->set_back_pointer_storage(back_pointer);
return result;
}
@@ -113,26 +109,24 @@ MaybeObject* TransitionArray::CopyInsert(String*
name, Map* target) {
result->SetPrototypeTransitions(GetPrototypeTransitions());
}
- FixedArray::WhitenessWitness witness(result);
-
if (insertion_index != kNotFound) {
for (int i = 0; i < number_of_transitions; ++i) {
- if (i != insertion_index) result->CopyFrom(this, i, i, witness);
+ if (i != insertion_index) result->CopyFrom(this, i, i);
}
- result->Set(insertion_index, name, target, witness);
+ result->Set(insertion_index, name, target);
return result;
}
insertion_index = 0;
for (; insertion_index < number_of_transitions; ++insertion_index) {
if (InsertionPointFound(GetKey(insertion_index), name)) break;
- result->CopyFrom(this, insertion_index, insertion_index, witness);
+ result->CopyFrom(this, insertion_index, insertion_index);
}
- result->Set(insertion_index, name, target, witness);
+ result->Set(insertion_index, name, target);
for (; insertion_index < number_of_transitions; ++insertion_index) {
- result->CopyFrom(this, insertion_index, insertion_index + 1, witness);
+ result->CopyFrom(this, insertion_index, insertion_index + 1);
}
result->set_back_pointer_storage(back_pointer_storage());
Index: src/transitions.h
diff --git a/src/transitions.h b/src/transitions.h
index
e79d6cae54f7d74c51c5380286b974f904ab1fa1..f937e847da91a8d06da02126fe78635bbcd6b460
100644
--- a/src/transitions.h
+++ b/src/transitions.h
@@ -113,8 +113,7 @@ class TransitionArray: public FixedArray {
// Copy a single transition from the origin array.
inline void CopyFrom(TransitionArray* origin,
int origin_transition,
- int target_transition,
- const WhitenessWitness& witness);
+ int target_transition);
// Search a transition for a given property name.
inline int Search(String* name);
@@ -184,8 +183,7 @@ class TransitionArray: public FixedArray {
inline void Set(int transition_number,
String* key,
- Map* target,
- const WhitenessWitness&);
+ Map* target);
DISALLOW_IMPLICIT_CONSTRUCTORS(TransitionArray);
};
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