Implement subclassing Arrays.

src/ia32/code-stubs-ia32.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_IA32
 
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
@@ skipping 4644 matching lines @@
 
   __ cmp(edx, edi);
   __ j(not_equal, &subclassing);
 
   Label no_info;
   // If the feedback vector is the undefined value call an array constructor
   // that doesn't use AllocationSites.
   __ cmp(ebx, isolate()->factory()->undefined_value());
   __ j(equal, &no_info);
 
-  __ cmp(edx, edi);
-  __ j(not_equal, &subclassing);
-
   // Only look at the lower 16 bits of the transition info.
   __ mov(edx, FieldOperand(ebx, AllocationSite::kTransitionInfoOffset));
   __ SmiUntag(edx);
   STATIC_ASSERT(AllocationSite::ElementsKindBits::kShift == 0);
   __ and_(edx, Immediate(AllocationSite::ElementsKindBits::kMask));
   GenerateDispatchToArrayStub(masm, DONT_OVERRIDE);
 
   __ bind(&no_info);
   GenerateDispatchToArrayStub(masm, DISABLE_ALLOCATION_SITES);
 
   __ bind(&subclassing);
-  __ TailCallRuntime(Runtime::kThrowArrayNotSubclassableError, 0, 1);
+  __ pop(ecx);  // return address.
+  __ push(edi);
+  __ push(edx);
+  __ add(eax, Immediate(2));

[mvstanton, 2015/03/02 16:46:18]

A comment about the add would be good, or maybe an overview comment indicating
that you are cleverly altering the arguments length.

+  __ push(ecx);
+  __ JumpToExternalReference(
+      ExternalReference(Runtime::kArrayConstructorWithSubclassing, isolate()));
 }
 
 
 void InternalArrayConstructorStub::GenerateCase(
     MacroAssembler* masm, ElementsKind kind) {
   Label not_zero_case, not_one_case;
   Label normal_sequence;
 
   __ test(eax, eax);
   __ j(not_zero, &not_zero_case);
@@ skipping 461 matching lines @@
                            ApiParameterOperand(2), kStackSpace, nullptr,
                            Operand(ebp, 7 * kPointerSize), NULL);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32