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

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/bootstrapper.h"
 #include "src/code-stubs.h"
@@ skipping 2357 matching lines @@
   int argc = state_.arg_count();
   ParameterCount actual(argc);
 
   EmitLoadTypeFeedbackVector(masm, ebx);
 
   __ LoadGlobalFunction(Context::ARRAY_FUNCTION_INDEX, ecx);
   __ cmp(edi, ecx);
   __ j(not_equal, &miss);
 
   __ mov(eax, arg_count());
-  __ mov(ebx, FieldOperand(ebx, edx, times_half_pointer_size,
+  __ mov(ecx, FieldOperand(ebx, edx, times_half_pointer_size,
                            FixedArray::kHeaderSize));
+
   // Verify that ecx contains an AllocationSite
-  __ AssertUndefinedOrAllocationSite(ebx);
+  Factory* factory = masm->isolate()->factory();
+  __ cmp(FieldOperand(ecx, HeapObject::kMapOffset),
+         factory->allocation_site_map());
+  __ j(not_equal, &miss);
+
+  __ mov(ebx, ecx);
   ArrayConstructorStub stub(masm->isolate(), arg_count());
   __ TailCallStub(&stub);
 
   __ bind(&miss);
   GenerateMiss(masm, IC::kCallIC_Customization_Miss);
 
   // The slow case, we need this no matter what to complete a call after a miss.
   CallFunctionNoFeedback(masm,
                          arg_count(),
                          true,
@@ skipping 50 matching lines @@
   Label miss;
 
   __ mov(ecx, FieldOperand(ebx, edx, times_half_pointer_size,
                            FixedArray::kHeaderSize));
   __ cmp(ecx, Immediate(TypeFeedbackInfo::MegamorphicSentinel(isolate)));
   __ j(equal, &slow_start);
   __ cmp(ecx, Immediate(TypeFeedbackInfo::UninitializedSentinel(isolate)));
   __ j(equal, &miss);
 
   if (!FLAG_trace_ic) {
-    // We are going megamorphic, and we don't want to visit the runtime.
+    // We are going megamorphic. If the feedback is a JSFunction, it is fine
+    // to handle it here. More complex cases are dealt with in the runtime.
+    __ AssertNotSmi(ecx);
+    __ CmpObjectType(ecx, JS_FUNCTION_TYPE, ecx);
+    __ j(not_equal, &miss);
     __ mov(FieldOperand(ebx, edx, times_half_pointer_size,
                         FixedArray::kHeaderSize),
            Immediate(TypeFeedbackInfo::MegamorphicSentinel(isolate)));
     __ jmp(&slow_start);
   }
 
   // We are here because tracing is on or we are going monomorphic.
   __ bind(&miss);
   GenerateMiss(masm, IC::kCallIC_Miss);
 
@@ skipping 2513 matching lines @@
                               Operand(ebp, 7 * kPointerSize),
                               NULL);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32