Revision: 11344
Author: [email protected]
Date: Tue Apr 17 00:52:39 2012
Log: Try aligning unboxed double array backing store in allocation or
scavenge promotion.
This CL does not align them during compaction or mark-sweep promotion
because we are not using specialized evacuation visitors.
[email protected]
Review URL: https://chromiumcodereview.appspot.com/10001012
http://code.google.com/p/v8/source/detail?r=11344
Modified:
/branches/bleeding_edge/src/heap.cc
/branches/bleeding_edge/src/ia32/codegen-ia32.cc
/branches/bleeding_edge/src/ia32/stub-cache-ia32.cc
/branches/bleeding_edge/src/v8globals.h
=======================================
--- /branches/bleeding_edge/src/heap.cc Tue Apr 17 00:16:19 2012
+++ /branches/bleeding_edge/src/heap.cc Tue Apr 17 00:52:39 2012
@@ -1482,6 +1482,27 @@
return new_space_front;
}
+
+
+STATIC_ASSERT((FixedDoubleArray::kHeaderSize & kDoubleAlignmentMask) == 0);
+
+
+INLINE(static HeapObject* EnsureDoubleAligned(Heap* heap,
+ HeapObject* object,
+ int size));
+
+static HeapObject* EnsureDoubleAligned(Heap* heap,
+ HeapObject* object,
+ int size) {
+ if ((OffsetFrom(object->address()) & kDoubleAlignmentMask) != 0) {
+ heap->CreateFillerObjectAt(object->address(), kPointerSize);
+ return HeapObject::FromAddress(object->address() + kPointerSize);
+ } else {
+ heap->CreateFillerObjectAt(object->address() + size - kPointerSize,
+ kPointerSize);
+ return object;
+ }
+}
enum LoggingAndProfiling {
@@ -1607,7 +1628,10 @@
}
}
- template<ObjectContents object_contents, SizeRestriction
size_restriction>
+
+ template<ObjectContents object_contents,
+ SizeRestriction size_restriction,
+ int alignment>
static inline void EvacuateObject(Map* map,
HeapObject** slot,
HeapObject* object,
@@ -1615,20 +1639,27 @@
SLOW_ASSERT((size_restriction != SMALL) ||
(object_size <= Page::kMaxNonCodeHeapObjectSize));
SLOW_ASSERT(object->Size() == object_size);
+
+ int allocation_size = object_size;
+ if (alignment != kObjectAlignment) {
+ ASSERT(alignment == kDoubleAlignment);
+ allocation_size += kPointerSize;
+ }
Heap* heap = map->GetHeap();
if (heap->ShouldBePromoted(object->address(), object_size)) {
MaybeObject* maybe_result;
if ((size_restriction != SMALL) &&
- (object_size > Page::kMaxNonCodeHeapObjectSize)) {
- maybe_result = heap->lo_space()->AllocateRaw(object_size,
+ (allocation_size > Page::kMaxNonCodeHeapObjectSize)) {
+ maybe_result = heap->lo_space()->AllocateRaw(allocation_size,
NOT_EXECUTABLE);
} else {
if (object_contents == DATA_OBJECT) {
- maybe_result = heap->old_data_space()->AllocateRaw(object_size);
+ maybe_result =
heap->old_data_space()->AllocateRaw(allocation_size);
} else {
- maybe_result =
heap->old_pointer_space()->AllocateRaw(object_size);
+ maybe_result =
+ heap->old_pointer_space()->AllocateRaw(allocation_size);
}
}
@@ -1636,6 +1667,10 @@
if (maybe_result->ToObject(&result)) {
HeapObject* target = HeapObject::cast(result);
+ if (alignment != kObjectAlignment) {
+ target = EnsureDoubleAligned(heap, target, allocation_size);
+ }
+
// Order is important: slot might be inside of the target if target
// was allocated over a dead object and slot comes from the store
// buffer.
@@ -1650,11 +1685,15 @@
return;
}
}
- MaybeObject* allocation = heap->new_space()->AllocateRaw(object_size);
+ MaybeObject* allocation =
heap->new_space()->AllocateRaw(allocation_size);
heap->promotion_queue()->SetNewLimit(heap->new_space()->top());
Object* result = allocation->ToObjectUnchecked();
HeapObject* target = HeapObject::cast(result);
+ if (alignment != kObjectAlignment) {
+ target = EnsureDoubleAligned(heap, target, allocation_size);
+ }
+
// Order is important: slot might be inside of the target if target
// was allocated over a dead object and slot comes from the store
// buffer.
@@ -1690,7 +1729,7 @@
HeapObject** slot,
HeapObject* object) {
int object_size = FixedArray::BodyDescriptor::SizeOf(map, object);
- EvacuateObject<POINTER_OBJECT, UNKNOWN_SIZE>(map,
+ EvacuateObject<POINTER_OBJECT, UNKNOWN_SIZE, kObjectAlignment>(map,
slot,
object,
object_size);
@@ -1702,10 +1741,11 @@
HeapObject* object) {
int length = reinterpret_cast<FixedDoubleArray*>(object)->length();
int object_size = FixedDoubleArray::SizeFor(length);
- EvacuateObject<DATA_OBJECT, UNKNOWN_SIZE>(map,
- slot,
- object,
- object_size);
+ EvacuateObject<DATA_OBJECT, UNKNOWN_SIZE, kDoubleAlignment>(
+ map,
+ slot,
+ object,
+ object_size);
}
@@ -1713,7 +1753,8 @@
HeapObject** slot,
HeapObject* object) {
int object_size =
reinterpret_cast<ByteArray*>(object)->ByteArraySize();
- EvacuateObject<DATA_OBJECT, UNKNOWN_SIZE>(map, slot, object,
object_size);
+ EvacuateObject<DATA_OBJECT, UNKNOWN_SIZE, kObjectAlignment>(
+ map, slot, object, object_size);
}
@@ -1722,7 +1763,8 @@
HeapObject* object) {
int object_size = SeqAsciiString::cast(object)->
SeqAsciiStringSize(map->instance_type());
- EvacuateObject<DATA_OBJECT, UNKNOWN_SIZE>(map, slot, object,
object_size);
+ EvacuateObject<DATA_OBJECT, UNKNOWN_SIZE, kObjectAlignment>(
+ map, slot, object, object_size);
}
@@ -1731,7 +1773,8 @@
HeapObject* object) {
int object_size = SeqTwoByteString::cast(object)->
SeqTwoByteStringSize(map->instance_type());
- EvacuateObject<DATA_OBJECT, UNKNOWN_SIZE>(map, slot, object,
object_size);
+ EvacuateObject<DATA_OBJECT, UNKNOWN_SIZE, kObjectAlignment>(
+ map, slot, object, object_size);
}
@@ -1774,7 +1817,8 @@
}
int object_size = ConsString::kSize;
- EvacuateObject<POINTER_OBJECT, SMALL>(map, slot, object, object_size);
+ EvacuateObject<POINTER_OBJECT, SMALL, kObjectAlignment>(
+ map, slot, object, object_size);
}
template<ObjectContents object_contents>
@@ -1784,14 +1828,16 @@
static inline void VisitSpecialized(Map* map,
HeapObject** slot,
HeapObject* object) {
- EvacuateObject<object_contents, SMALL>(map, slot, object,
object_size);
+ EvacuateObject<object_contents, SMALL, kObjectAlignment>(
+ map, slot, object, object_size);
}
static inline void Visit(Map* map,
HeapObject** slot,
HeapObject* object) {
int object_size = map->instance_size();
- EvacuateObject<object_contents, SMALL>(map, slot, object,
object_size);
+ EvacuateObject<object_contents, SMALL, kObjectAlignment>(
+ map, slot, object, object_size);
}
};
@@ -4666,6 +4712,11 @@
AllocationSpace space =
(pretenure == TENURED) ? OLD_DATA_SPACE : NEW_SPACE;
int size = FixedDoubleArray::SizeFor(length);
+
+#ifndef V8_HOST_ARCH_64_BIT
+ size += kPointerSize;
+#endif
+
if (space == NEW_SPACE && size > kMaxObjectSizeInNewSpace) {
// Too big for new space.
space = LO_SPACE;
@@ -4678,7 +4729,12 @@
AllocationSpace retry_space =
(size <= Page::kMaxNonCodeHeapObjectSize) ? OLD_DATA_SPACE :
LO_SPACE;
- return AllocateRaw(size, space, retry_space);
+ HeapObject* object;
+ { MaybeObject* maybe_object = AllocateRaw(size, space, retry_space);
+ if (!maybe_object->To<HeapObject>(&object)) return maybe_object;
+ }
+
+ return EnsureDoubleAligned(this, object, size);
}
=======================================
--- /branches/bleeding_edge/src/ia32/codegen-ia32.cc Mon Mar 12 07:56:04
2012
+++ /branches/bleeding_edge/src/ia32/codegen-ia32.cc Tue Apr 17 00:52:39
2012
@@ -397,9 +397,25 @@
// Allocate new FixedDoubleArray.
// edx: receiver
// edi: length of source FixedArray (smi-tagged)
- __ lea(esi, Operand(edi, times_4, FixedDoubleArray::kHeaderSize));
+ __ lea(esi, Operand(edi,
+ times_4,
+ FixedDoubleArray::kHeaderSize + kPointerSize));
__ AllocateInNewSpace(esi, eax, ebx, no_reg, &gc_required, TAG_OBJECT);
+ Label aligned, aligned_done;
+ __ test(eax, Immediate(kDoubleAlignmentMask - kHeapObjectTag));
+ __ j(zero, &aligned, Label::kNear);
+ __ mov(FieldOperand(eax, 0),
+ Immediate(masm->isolate()->factory()->one_pointer_filler_map()));
+ __ add(eax, Immediate(kPointerSize));
+ __ jmp(&aligned_done);
+
+ __ bind(&aligned);
+ __ mov(Operand(eax, esi, times_1, -kPointerSize-1),
+ Immediate(masm->isolate()->factory()->one_pointer_filler_map()));
+
+ __ bind(&aligned_done);
+
// eax: destination FixedDoubleArray
// edi: number of elements
// edx: receiver
=======================================
--- /branches/bleeding_edge/src/ia32/stub-cache-ia32.cc Fri Apr 13 02:38:00
2012
+++ /branches/bleeding_edge/src/ia32/stub-cache-ia32.cc Tue Apr 17 00:52:39
2012
@@ -4030,6 +4030,7 @@
int size =
FixedDoubleArray::SizeFor(JSArray::kPreallocatedArrayElements);
__ AllocateInNewSpace(size, edi, ebx, ecx, &prepare_slow, TAG_OBJECT);
+
// Restore the key, which is known to be the array length.
__ mov(ecx, Immediate(0));
=======================================
--- /branches/bleeding_edge/src/v8globals.h Mon Feb 20 06:02:59 2012
+++ /branches/bleeding_edge/src/v8globals.h Tue Apr 17 00:52:39 2012
@@ -48,6 +48,10 @@
const intptr_t kPointerAlignment = (1 << kPointerSizeLog2);
const intptr_t kPointerAlignmentMask = kPointerAlignment - 1;
+// Desired alignment for double values.
+const intptr_t kDoubleAlignment = 8;
+const intptr_t kDoubleAlignmentMask = kDoubleAlignment - 1;
+
// Desired alignment for maps.
#if V8_HOST_ARCH_64_BIT
const intptr_t kMapAlignmentBits = kObjectAlignmentBits;
--
v8-dev mailing list
[email protected]
http://groups.google.com/group/v8-dev
