Revision: 10711
Author: [email protected]
Date: Wed Feb 15 04:13:55 2012
Log: Remove unnecessary elements type check when allocating array in
runtime.
BUG=
TEST=--smi-only-arrays should be perf-neutral to allocating big arrays in a
tight loop.
Review URL: https://chromiumcodereview.appspot.com/9356002
http://code.google.com/p/v8/source/detail?r=10711
Modified:
/branches/bleeding_edge/src/builtins.cc
/branches/bleeding_edge/src/heap.cc
=======================================
--- /branches/bleeding_edge/src/builtins.cc Wed Feb 8 01:50:13 2012
+++ /branches/bleeding_edge/src/builtins.cc Wed Feb 15 04:13:55 2012
@@ -218,12 +218,13 @@
if (obj->IsSmi()) {
int len = Smi::cast(obj)->value();
if (len >= 0 && len < JSObject::kInitialMaxFastElementArray) {
- Object* obj;
+ Object* fixed_array;
{ MaybeObject* maybe_obj = heap->AllocateFixedArrayWithHoles(len);
- if (!maybe_obj->ToObject(&obj)) return maybe_obj;
- }
- MaybeObject* maybe_obj = array->SetContent(FixedArray::cast(obj));
- if (maybe_obj->IsFailure()) return maybe_obj;
+ if (!maybe_obj->ToObject(&fixed_array)) return maybe_obj;
+ }
+ // We do not use SetContent to skip the unnecessary elements type
check.
+ array->set_elements(FixedArray::cast(fixed_array));
+ array->set_length(Smi::cast(obj));
return array;
}
}
=======================================
--- /branches/bleeding_edge/src/heap.cc Fri Feb 10 04:36:05 2012
+++ /branches/bleeding_edge/src/heap.cc Wed Feb 15 04:13:55 2012
@@ -4361,10 +4361,10 @@
Context* global_context = isolate()->context()->global_context();
JSFunction* array_function = global_context->array_function();
Map* map = array_function->initial_map();
- if (elements_kind == FAST_ELEMENTS || !FLAG_smi_only_arrays) {
- map = Map::cast(global_context->object_js_array_map());
- } else if (elements_kind == FAST_DOUBLE_ELEMENTS) {
+ if (elements_kind == FAST_DOUBLE_ELEMENTS) {
map = Map::cast(global_context->double_js_array_map());
+ } else if (elements_kind == FAST_ELEMENTS || !FLAG_smi_only_arrays) {
+ map = Map::cast(global_context->object_js_array_map());
} else {
ASSERT(elements_kind == FAST_SMI_ONLY_ELEMENTS);
ASSERT(map == global_context->smi_js_array_map());
--
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