Disallow subclassing Arrays.

src/arm/code-stubs-arm.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_ARM
 
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
@@ skipping 2645 matching lines @@
   __ mov(r0, Operand(arg_count()));
   __ add(r4, r2, Operand::PointerOffsetFromSmiKey(r3));
   __ ldr(r4, FieldMemOperand(r4, FixedArray::kHeaderSize));
 
   // Verify that r4 contains an AllocationSite
   __ ldr(r5, FieldMemOperand(r4, HeapObject::kMapOffset));
   __ CompareRoot(r5, Heap::kAllocationSiteMapRootIndex);
   __ b(ne, &miss);
 
   __ mov(r2, r4);
+  __ mov(r3, r1);
   ArrayConstructorStub stub(masm->isolate(), arg_count());
   __ TailCallStub(&stub);
 
   __ bind(&miss);
   GenerateMiss(masm);
 
   // The slow case, we need this no matter what to complete a call after a miss.
   CallFunctionNoFeedback(masm,
                          arg_count(),
                          true,
@@ skipping 1890 matching lines @@
     UNREACHABLE();
   }
 }
 
 
 void ArrayConstructorStub::Generate(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- r0 : argc (only if argument_count() == ANY)
   //  -- r1 : constructor
   //  -- r2 : AllocationSite or undefined
+  //  -- r3 : original constructor
   //  -- sp[0] : return address
   //  -- sp[4] : last argument
   // -----------------------------------
 
   if (FLAG_debug_code) {
     // The array construct code is only set for the global and natives
     // builtin Array functions which always have maps.
 
     // Initial map for the builtin Array function should be a map.
     __ ldr(r4, FieldMemOperand(r1, JSFunction::kPrototypeOrInitialMapOffset));
     // Will both indicate a NULL and a Smi.
     __ tst(r4, Operand(kSmiTagMask));
     __ Assert(ne, kUnexpectedInitialMapForArrayFunction);
     __ CompareObjectType(r4, r4, r5, MAP_TYPE);
     __ Assert(eq, kUnexpectedInitialMapForArrayFunction);
 
     // We should either have undefined in r2 or a valid AllocationSite
     __ AssertUndefinedOrAllocationSite(r2, r4);
   }
 
+  Label subclassing;
+  __ cmp(r3, r1);
+  __ b(ne, &subclassing);
+
   Label no_info;
   // Get the elements kind and case on that.
   __ CompareRoot(r2, Heap::kUndefinedValueRootIndex);
   __ b(eq, &no_info);
 
   __ 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);
+
+  __ bind(&subclassing);
+  __ TailCallRuntime(Runtime::kThrowArrayNotSubclassableError, 0, 1);
 }
 
 
 void InternalArrayConstructorStub::GenerateCase(
     MacroAssembler* masm, ElementsKind kind) {
   __ cmp(r0, Operand(1));
 
   InternalArrayNoArgumentConstructorStub stub0(isolate(), kind);
   __ TailCallStub(&stub0, lo);
 
@@ skipping 383 matching lines @@
                            kStackUnwindSpace, NULL,
                            MemOperand(fp, 6 * kPointerSize), NULL);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM