Disallow subclassing Arrays.

src/x64/code-stubs-x64.cc

Index: src/x64/code-stubs-x64.cc
diff --git a/src/x64/code-stubs-x64.cc b/src/x64/code-stubs-x64.cc
index 23565140bf890caf77a23ab2f313b9125754f19f..eabb22690ab7843ce198eb23a805ff384b1ccea1 100644
--- a/src/x64/code-stubs-x64.cc
+++ b/src/x64/code-stubs-x64.cc
@@ -2122,6 +2122,7 @@ void CallIC_ArrayStub::Generate(MacroAssembler* masm) {
   __ j(not_equal, &miss);
 
   __ movp(rbx, rcx);
+  __ movp(rdx, rdi);
   ArrayConstructorStub stub(masm->isolate(), arg_count());
   __ TailCallStub(&stub);
 
@@ -4572,6 +4573,7 @@ void ArrayConstructorStub::Generate(MacroAssembler* masm) {
   //  -- rax    : argc
   //  -- rbx    : AllocationSite or undefined
   //  -- rdi    : constructor
+  //  -- rdx    : original constructor
   //  -- rsp[0] : return address
   //  -- rsp[8] : last argument
   // -----------------------------------
@@ -4592,6 +4594,10 @@ void ArrayConstructorStub::Generate(MacroAssembler* masm) {
     __ AssertUndefinedOrAllocationSite(rbx);
   }
 
+  Label subclassing;
+  __ cmpp(rdi, rdx);
+  __ j(not_equal, &subclassing);
+
   Label no_info;
   // If the feedback vector is the undefined value call an array constructor
   // that doesn't use AllocationSites.
@@ -4607,6 +4613,9 @@ void ArrayConstructorStub::Generate(MacroAssembler* masm) {
 
   __ bind(&no_info);
   GenerateDispatchToArrayStub(masm, DISABLE_ALLOCATION_SITES);
+
+  __ bind(&subclassing);
+  __ TailCallRuntime(Runtime::kThrowArrayNotSubclassableError, 0, 1);
 }