Revision: 10024
Author: [email protected]
Date: Thu Nov 17 09:22:21 2011
Log: Optimize array literal boilerplate copy for fast cases.
[email protected]
BUG=none
TEST=none
Review URL: http://codereview.chromium.org/8590026
http://code.google.com/p/v8/source/detail?r=10024
Modified:
/branches/bleeding_edge/src/ia32/full-codegen-ia32.cc
/branches/bleeding_edge/src/x64/code-stubs-x64.cc
/branches/bleeding_edge/src/x64/full-codegen-x64.cc
=======================================
--- /branches/bleeding_edge/src/ia32/full-codegen-ia32.cc Thu Nov 17
07:08:59 2011
+++ /branches/bleeding_edge/src/ia32/full-codegen-ia32.cc Thu Nov 17
09:22:21 2011
@@ -1477,10 +1477,9 @@
int length = subexprs->length();
Handle<FixedArray> constant_elements = expr->constant_elements();
ASSERT_EQ(2, constant_elements->length());
-#if DEBUG
ElementsKind constant_elements_kind =
static_cast<ElementsKind>(Smi::cast(constant_elements->get(0))->value());
-#endif
+ bool has_constant_fast_elements = constant_elements_kind ==
FAST_ELEMENTS;
Handle<FixedArrayBase> constant_elements_values(
FixedArrayBase::cast(constant_elements->get(1)));
@@ -1488,7 +1487,17 @@
__ push(FieldOperand(ebx, JSFunction::kLiteralsOffset));
__ push(Immediate(Smi::FromInt(expr->literal_index())));
__ push(Immediate(constant_elements));
- if (expr->depth() > 1) {
+ Heap* heap = isolate()->heap();
+ if (has_constant_fast_elements &&
+ constant_elements_values->map() == heap->fixed_cow_array_map()) {
+ // If the elements are already FAST_ELEMENTS, the boilerplate cannot
+ // change, so it's possible to specialize the stub in advance.
+ __ IncrementCounter(isolate()->counters()->cow_arrays_created_stub(),
1);
+ FastCloneShallowArrayStub stub(
+ FastCloneShallowArrayStub::COPY_ON_WRITE_ELEMENTS,
+ length);
+ __ CallStub(&stub);
+ } else if (expr->depth() > 1) {
__ CallRuntime(Runtime::kCreateArrayLiteral, 3);
} else if (length > FastCloneShallowArrayStub::kMaximumClonedLength) {
__ CallRuntime(Runtime::kCreateArrayLiteralShallow, 3);
@@ -1496,13 +1505,12 @@
ASSERT(constant_elements_kind == FAST_ELEMENTS ||
constant_elements_kind == FAST_SMI_ONLY_ELEMENTS ||
FLAG_smi_only_arrays);
- if (constant_elements_values->map() ==
- isolate()->heap()->fixed_cow_array_map()) {
- __ IncrementCounter(isolate()->counters()->cow_arrays_created_stub(),
- 1);
- }
- FastCloneShallowArrayStub stub(
- FastCloneShallowArrayStub::CLONE_ANY_ELEMENTS, length);
+ // If the elements are already FAST_ELEMENTS, the boilerplate cannot
+ // change, so it's possible to specialize the stub in advance.
+ FastCloneShallowArrayStub::Mode mode = has_constant_fast_elements
+ ? FastCloneShallowArrayStub::CLONE_ELEMENTS
+ : FastCloneShallowArrayStub::CLONE_ANY_ELEMENTS;
+ FastCloneShallowArrayStub stub(mode, length);
__ CallStub(&stub);
}
=======================================
--- /branches/bleeding_edge/src/x64/code-stubs-x64.cc Thu Nov 17 07:08:59
2011
+++ /branches/bleeding_edge/src/x64/code-stubs-x64.cc Thu Nov 17 09:22:21
2011
@@ -226,7 +226,7 @@
Label* fail) {
// Registers on entry:
//
- // rcx: boilerplate array.
+ // rcx: boilerplate literal array.
ASSERT(mode != FastCloneShallowArrayStub::CLONE_ANY_ELEMENTS);
// All sizes here are multiples of kPointerSize.
@@ -315,7 +315,7 @@
__ Cmp(FieldOperand(rbx, HeapObject::kMapOffset),
factory->fixed_array_map());
__ j(not_equal, &double_elements);
- GenerateFastCloneShallowArrayCommon(masm, 0,
+ GenerateFastCloneShallowArrayCommon(masm, length_,
CLONE_ELEMENTS, &slow_case);
__ ret(3 * kPointerSize);
@@ -346,8 +346,7 @@
__ pop(rcx);
}
- GenerateFastCloneShallowArrayCommon(masm, 0,
- CLONE_DOUBLE_ELEMENTS, &slow_case);
+ GenerateFastCloneShallowArrayCommon(masm, length_, mode, &slow_case);
__ ret(3 * kPointerSize);
__ bind(&slow_case);
=======================================
--- /branches/bleeding_edge/src/x64/full-codegen-x64.cc Thu Nov 17 07:08:59
2011
+++ /branches/bleeding_edge/src/x64/full-codegen-x64.cc Thu Nov 17 09:22:21
2011
@@ -1480,10 +1480,9 @@
int length = subexprs->length();
Handle<FixedArray> constant_elements = expr->constant_elements();
ASSERT_EQ(2, constant_elements->length());
-#if DEBUG
ElementsKind constant_elements_kind =
static_cast<ElementsKind>(Smi::cast(constant_elements->get(0))->value());
-#endif
+ bool has_constant_fast_elements = constant_elements_kind ==
FAST_ELEMENTS;
Handle<FixedArrayBase> constant_elements_values(
FixedArrayBase::cast(constant_elements->get(1)));
@@ -1491,7 +1490,17 @@
__ push(FieldOperand(rbx, JSFunction::kLiteralsOffset));
__ Push(Smi::FromInt(expr->literal_index()));
__ Push(constant_elements);
- if (expr->depth() > 1) {
+ Heap* heap = isolate()->heap();
+ if (has_constant_fast_elements &&
+ constant_elements_values->map() == heap->fixed_cow_array_map()) {
+ // If the elements are already FAST_ELEMENTS, the boilerplate cannot
+ // change, so it's possible to specialize the stub in advance.
+ __ IncrementCounter(isolate()->counters()->cow_arrays_created_stub(),
1);
+ FastCloneShallowArrayStub stub(
+ FastCloneShallowArrayStub::COPY_ON_WRITE_ELEMENTS,
+ length);
+ __ CallStub(&stub);
+ } else if (expr->depth() > 1) {
__ CallRuntime(Runtime::kCreateArrayLiteral, 3);
} else if (length > FastCloneShallowArrayStub::kMaximumClonedLength) {
__ CallRuntime(Runtime::kCreateArrayLiteralShallow, 3);
@@ -1499,13 +1508,12 @@
ASSERT(constant_elements_kind == FAST_ELEMENTS ||
constant_elements_kind == FAST_SMI_ONLY_ELEMENTS ||
FLAG_smi_only_arrays);
- if (constant_elements_values->map() ==
- isolate()->heap()->fixed_cow_array_map()) {
- __ IncrementCounter(isolate()->counters()->cow_arrays_created_stub(),
- 1);
- }
- FastCloneShallowArrayStub stub(
- FastCloneShallowArrayStub::CLONE_ANY_ELEMENTS, length);
+ // If the elements are already FAST_ELEMENTS, the boilerplate cannot
+ // change, so it's possible to specialize the stub in advance.
+ FastCloneShallowArrayStub::Mode mode = has_constant_fast_elements
+ ? FastCloneShallowArrayStub::CLONE_ELEMENTS
+ : FastCloneShallowArrayStub::CLONE_ANY_ELEMENTS;
+ FastCloneShallowArrayStub stub(mode, length);
__ CallStub(&stub);
}
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