Adapt Danno's Track Allocation Info idea to fast literals. When allocating a literal array,

src/ia32/macro-assembler-ia32.cc

Index: src/ia32/macro-assembler-ia32.cc
diff --git a/src/ia32/macro-assembler-ia32.cc b/src/ia32/macro-assembler-ia32.cc
index 7b41defabfecd86fbf47cfe8206e59f099f40591..c0e1f378d33d790ab8c2b87056367276d2ebbd22 100644
--- a/src/ia32/macro-assembler-ia32.cc
+++ b/src/ia32/macro-assembler-ia32.cc
@@ -3051,6 +3051,31 @@ void MacroAssembler::CheckEnumCache(Label* call_runtime) {
   j(not_equal, &next);
 }
 
+
+void MacroAssembler::TestJSArrayForAllocationSiteInfo(
+    Register receiver_reg,
+    Register scratch_reg,
+    Label* allocation_info_present) {
+  Label no_info_available;
+  ExternalReference new_space_start =
+      ExternalReference::new_space_start(isolate());
+  ExternalReference new_space_allocation_top =
+      ExternalReference::new_space_allocation_top_address(isolate());
+
+  lea(scratch_reg, Operand(receiver_reg,
+                           JSArray::kSize + AllocationSiteInfo::kSize));
+  cmp(scratch_reg, Immediate(new_space_start));
+  j(less, &no_info_available);
+  cmp(scratch_reg, Operand::StaticVariable(new_space_allocation_top));
+  j(greater_equal, &no_info_available);
+  cmp(MemOperand(scratch_reg, 0),
+      Immediate(Handle<Map>(isolate()->heap()->
+                               allocation_site_info_map())));

[danno, 2013/01/07 08:03:48]

nit: indentation (4 spaces)

[mvstanton, 2013/01/07 09:28:41]

Done.

+  j(equal, allocation_info_present);
+  bind(&no_info_available);
+}
+
+
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32