CallIC customization stubs must accept that a vector slot is cleared.

src/arm64/code-stubs-arm64.cc

Index: src/arm64/code-stubs-arm64.cc
diff --git a/src/arm64/code-stubs-arm64.cc b/src/arm64/code-stubs-arm64.cc
index 6a98589b022eee28a5510e4a2675559297f171d7..21a7e7dccef0367ebcbe31714c4f57f6bcafc081 100644
--- a/src/arm64/code-stubs-arm64.cc
+++ b/src/arm64/code-stubs-arm64.cc
@@ -3230,15 +3230,19 @@ void CallIC_ArrayStub::Generate(MacroAssembler* masm) {
   __ Cmp(function, scratch);
   __ B(ne, &miss);
 
-  Register allocation_site = feedback_vector;
   __ Mov(x0, Operand(arg_count()));
 
   __ Add(scratch, feedback_vector,
          Operand::UntagSmiAndScale(index, kPointerSizeLog2));
-  __ Ldr(allocation_site, FieldMemOperand(scratch, FixedArray::kHeaderSize));
+  __ Ldr(scratch, FieldMemOperand(scratch, FixedArray::kHeaderSize));
+
+  // Verify that scratch contains an AllocationSite
+  Register map = x5;
+  __ Ldr(map, FieldMemOperand(scratch, AllocationSite::kMapOffset));

[Toon Verwaest, 2014/07/28 14:11:38]

HeapObject::kMapOffset?
(You don't know yet whether it's an AllocationSite, just that it's a HeapObject)

[mvstanton, 2014/07/28 16:02:50]

Right, we will store in this slot the uninitialized symbol, the megamorphic
symbol, a function pointer or an allocationsite. Since those are all heap
objects with maps, I can dereference here. Changed to HeapObject::kMapOffset.

+  __ JumpIfNotRoot(map, Heap::kAllocationSiteMapRootIndex, &miss);
 
-  // Verify that x2 contains an AllocationSite
-  __ AssertUndefinedOrAllocationSite(allocation_site, scratch);
+  Register allocation_site = feedback_vector;
+  __ Mov(allocation_site, scratch);
   ArrayConstructorStub stub(masm->isolate(), arg_count());
   __ TailCallStub(&stub);