X87: Disallow subclassing Arrays.

src/x87/code-stubs-x87.cc

Index: src/x87/code-stubs-x87.cc
diff --git a/src/x87/code-stubs-x87.cc b/src/x87/code-stubs-x87.cc
index 5e69b809b05cbd9abcd70b33ea481acacf5cdb76..5da200d66e8c6b60d66dd9deeaabb10197981820 100644
--- a/src/x87/code-stubs-x87.cc
+++ b/src/x87/code-stubs-x87.cc
@@ -1939,6 +1939,7 @@ void CallIC_ArrayStub::Generate(MacroAssembler* masm) {
   __ j(not_equal, &miss);
 
   __ mov(ebx, ecx);
+  __ mov(edx, edi);
   ArrayConstructorStub stub(masm->isolate(), arg_count());
   __ TailCallStub(&stub);
 
@@ -4290,6 +4291,7 @@ void ArrayConstructorStub::Generate(MacroAssembler* masm) {
   //  -- eax : argc (only if argument_count() == ANY)
   //  -- ebx : AllocationSite or undefined
   //  -- edi : constructor
+  //  -- edx : Original constructor
   //  -- esp[0] : return address
   //  -- esp[4] : last argument
   // -----------------------------------
@@ -4309,12 +4311,20 @@ void ArrayConstructorStub::Generate(MacroAssembler* masm) {
     __ AssertUndefinedOrAllocationSite(ebx);
   }
 
+  Label subclassing;
+
+  __ 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);
@@ -4324,6 +4334,9 @@ void ArrayConstructorStub::Generate(MacroAssembler* masm) {
 
   __ bind(&no_info);
   GenerateDispatchToArrayStub(masm, DISABLE_ALLOCATION_SITES);
+
+  __ bind(&subclassing);
+  __ TailCallRuntime(Runtime::kThrowArrayNotSubclassableError, 0, 1);
 }