Megamorphic KeyedLoadIC needs special handling for vector ics.

src/ic/x64/ic-x64.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_X64
 
 #include "src/codegen.h"
 #include "src/ic/ic.h"
@@ skipping 314 matching lines @@
   GenerateKeyedLoadReceiverCheck(masm, receiver, rax, Map::kHasNamedInterceptor,
                                  &slow);
 
   // If the receiver is a fast-case object, check the stub cache. Otherwise
   // probe the dictionary.
   __ movp(rbx, FieldOperand(receiver, JSObject::kPropertiesOffset));
   __ CompareRoot(FieldOperand(rbx, HeapObject::kMapOffset),
                  Heap::kHashTableMapRootIndex);
   __ j(equal, &probe_dictionary);
 
+  Register megamorphic_scratch = rdi;
+  if (FLAG_vector_ics) {
+    // When vector ics are in use, the handlers in the stub cache expect a
+    // vector and slot. Since we won't change the IC from any downstream
+    // misses, a dummy vector can be used.
+    Register vector = VectorLoadICDescriptor::VectorRegister();
+    Register slot = VectorLoadICDescriptor::SlotRegister();
+    DCHECK(!AreAliased(megamorphic_scratch, vector, slot));
+    Handle<TypeFeedbackVector> dummy_vector = Handle<TypeFeedbackVector>::cast(
+        masm->isolate()->factory()->keyed_load_dummy_vector());
+    int int_slot = dummy_vector->GetIndex(FeedbackVectorICSlot(0));
+    __ Move(vector, dummy_vector);
+    __ Move(slot, Smi::FromInt(int_slot));
+  }
+
   Code::Flags flags = Code::RemoveTypeAndHolderFromFlags(
       Code::ComputeHandlerFlags(Code::LOAD_IC));
-  masm->isolate()->stub_cache()->GenerateProbe(
-      masm, Code::LOAD_IC, flags, false, receiver, key, rbx, no_reg);
+  masm->isolate()->stub_cache()->GenerateProbe(masm, Code::KEYED_LOAD_IC, flags,
+                                               false, receiver, key,
+                                               megamorphic_scratch, no_reg);
   // Cache miss.
   GenerateMiss(masm);
 
   // Do a quick inline probe of the receiver's dictionary, if it
   // exists.
   __ bind(&probe_dictionary);
   // rbx: elements
 
   __ movp(rax, FieldOperand(receiver, JSObject::kMapOffset));
   __ movb(rax, FieldOperand(rax, Map::kInstanceTypeOffset));
@@ skipping 597 matching lines @@
   Condition cc =
       (check == ENABLE_INLINED_SMI_CHECK)
           ? (*jmp_address == Assembler::kJncShortOpcode ? not_zero : zero)
           : (*jmp_address == Assembler::kJnzShortOpcode ? not_carry : carry);
   *jmp_address = static_cast<byte>(Assembler::kJccShortPrefix | cc);
 }
 }
 }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64