Array constructor shouldn't require a Cell, just an AllocationSite.

src/arm/code-stubs-arm.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 182 matching lines @@
 }
 
 
 static void InitializeArrayConstructorDescriptor(
     Isolate* isolate,
     CodeStubInterfaceDescriptor* descriptor,
     int constant_stack_parameter_count) {
   // register state
   // r0 -- number of arguments
   // r1 -- function
-  // r2 -- type info cell with elements kind
+  // r2 -- allocation site with elements kind
   static Register registers_variable_args[] = { r1, r2, r0 };
   static Register registers_no_args[] = { r1, r2 };
 
   if (constant_stack_parameter_count == 0) {
     descriptor->register_param_count_ = 2;
     descriptor->register_params_ = registers_no_args;
   } else {
     // stack param count needs (constructor pointer, and single argument)
     descriptor->handler_arguments_mode_ = PASS_ARGUMENTS;
     descriptor->stack_parameter_count_ = r0;
@@ skipping 5359 matching lines @@
     // If we reached this point there is a problem.
     __ Abort(kUnexpectedElementsKindInArrayConstructor);
   } else {
     UNREACHABLE();
   }
 }
 
 
 static void CreateArrayDispatchOneArgument(MacroAssembler* masm,
                                            AllocationSiteOverrideMode mode) {
-  // r2 - type info cell (if mode != DISABLE_ALLOCATION_SITES)
+  // r2 - allocation site (if mode != DISABLE_ALLOCATION_SITES)
   // r3 - kind (if mode != DISABLE_ALLOCATION_SITES)
   // r0 - number of arguments
   // r1 - constructor?
   // sp[0] - last argument
   Label normal_sequence;
   if (mode == DONT_OVERRIDE) {
     ASSERT(FAST_SMI_ELEMENTS == 0);
     ASSERT(FAST_HOLEY_SMI_ELEMENTS == 1);
     ASSERT(FAST_ELEMENTS == 2);
     ASSERT(FAST_HOLEY_ELEMENTS == 3);
@@ skipping 19 matching lines @@
     __ TailCallStub(&stub_holey);
 
     __ bind(&normal_sequence);
     ArraySingleArgumentConstructorStub stub(initial,
                                             DISABLE_ALLOCATION_SITES);
     __ TailCallStub(&stub);
   } else if (mode == DONT_OVERRIDE) {
     // We are going to create a holey array, but our kind is non-holey.
     // Fix kind and retry (only if we have an allocation site in the cell).
     __ add(r3, r3, Operand(1));
-    __ ldr(r5, FieldMemOperand(r2, Cell::kValueOffset));
-
-    if (FLAG_debug_code) {
-      __ ldr(r5, FieldMemOperand(r5, 0));
-      __ CompareRoot(r5, Heap::kAllocationSiteMapRootIndex);

[Benedikt Meurer, 2014/01/20 12:24:22]

Can we please keep this check?

[mvstanton, 2014/01/20 13:36:11]

Sure thing, done for all platforms.

-      __ Assert(eq, kExpectedAllocationSiteInCell);
-      __ ldr(r5, FieldMemOperand(r2, Cell::kValueOffset));
-    }
 
     // Save the resulting elements kind in type info. We can't just store r3
     // in the AllocationSite::transition_info field because elements kind is
     // restricted to a portion of the field...upper bits need to be left alone.
     STATIC_ASSERT(AllocationSite::ElementsKindBits::kShift == 0);
-    __ ldr(r4, FieldMemOperand(r5, AllocationSite::kTransitionInfoOffset));
+    __ ldr(r4, FieldMemOperand(r2, AllocationSite::kTransitionInfoOffset));
     __ add(r4, r4, Operand(Smi::FromInt(kFastElementsKindPackedToHoley)));
-    __ str(r4, FieldMemOperand(r5, AllocationSite::kTransitionInfoOffset));
+    __ str(r4, FieldMemOperand(r2, AllocationSite::kTransitionInfoOffset));
 
     __ bind(&normal_sequence);
     int last_index = GetSequenceIndexFromFastElementsKind(
         TERMINAL_FAST_ELEMENTS_KIND);
     for (int i = 0; i <= last_index; ++i) {
       ElementsKind kind = GetFastElementsKindFromSequenceIndex(i);
       __ cmp(r3, Operand(kind));
       ArraySingleArgumentConstructorStub stub(kind);
       __ TailCallStub(&stub, eq);
     }
@@ skipping 103 matching lines @@
     __ ldr(r3, FieldMemOperand(r2, 0));
     __ cmp(r3, Operand(cell_map));
     __ Assert(eq, kExpectedPropertyCellInRegisterEbx);
     __ bind(&okay_here);
   }
 
   Label no_info;
   // Get the elements kind and case on that.
   __ CompareRoot(r2, Heap::kUndefinedValueRootIndex);
   __ b(eq, &no_info);
-  __ ldr(r3, FieldMemOperand(r2, Cell::kValueOffset));
+  __ ldr(r2, FieldMemOperand(r2, Cell::kValueOffset));
 
   // If the type cell is undefined, or contains anything other than an
   // AllocationSite, call an array constructor that doesn't use AllocationSites.
-  __ ldr(r4, FieldMemOperand(r3, 0));
+  __ ldr(r4, FieldMemOperand(r2, 0));
   __ CompareRoot(r4, Heap::kAllocationSiteMapRootIndex);
   __ b(ne, &no_info);
 
-  __ ldr(r3, FieldMemOperand(r3, AllocationSite::kTransitionInfoOffset));
+  __ ldr(r3, FieldMemOperand(r2, AllocationSite::kTransitionInfoOffset));
   __ SmiUntag(r3);
   STATIC_ASSERT(AllocationSite::ElementsKindBits::kShift == 0);
   __ and_(r3, r3, Operand(AllocationSite::ElementsKindBits::kMask));
   GenerateDispatchToArrayStub(masm, DONT_OVERRIDE);
 
   __ bind(&no_info);
   GenerateDispatchToArrayStub(masm, DISABLE_ALLOCATION_SITES);
 }
 
 
@@ skipping 70 matching lines @@
   __ bind(&fast_elements_case);
   GenerateCase(masm, FAST_ELEMENTS);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM