Do not try to collect the map if the monomorphic IC stub has no map.

This is necessary for monomorphic stubs that rely on instance types,
such as ArrayLength, StringLength and FunctionPrototype.

BUG=chromium:172345

Review URL: https://chromiumcodereview.appspot.com/12082023

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13526 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/ic.cc

@@ -1139,32 +1139,35 @@ static bool AddOneReceiverMapIfMissing(MapHandleList* receiver_maps,
 static void GetReceiverMapsForStub(Handle<Code> stub,
                                    MapHandleList* result) {
   ASSERT(stub->is_inline_cache_stub());
-  if (stub->is_keyed_load_stub() || stub->is_keyed_store_stub()) {
-    switch (stub->ic_state()) {
-      case MONOMORPHIC:
-        result->Add(Handle<Map>(stub->FindFirstMap()));
-        break;
-      case POLYMORPHIC: {
-        AssertNoAllocation no_allocation;
-        int mask = RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT);
-        for (RelocIterator it(*stub, mask); !it.done(); it.next()) {
-          RelocInfo* info = it.rinfo();
-          Handle<Object> object(info->target_object());
-          ASSERT(object->IsMap());
-          AddOneReceiverMapIfMissing(result, Handle<Map>::cast(object));
-        }
-        break;
+  ASSERT(stub->is_keyed_load_stub() || stub->is_keyed_store_stub());
+  switch (stub->ic_state()) {
+    case MONOMORPHIC: {
+      Map* map = stub->FindFirstMap();
+      if (map != NULL) {
+        result->Add(Handle<Map>(map));
+      }
+      break;
+    }
+    case POLYMORPHIC: {
+      AssertNoAllocation no_allocation;
+      int mask = RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT);
+      for (RelocIterator it(*stub, mask); !it.done(); it.next()) {
+        RelocInfo* info = it.rinfo();
+        Handle<Object> object(info->target_object());
+        ASSERT(object->IsMap());
+        AddOneReceiverMapIfMissing(result, Handle<Map>::cast(object));
       }
-      case MEGAMORPHIC:
-      case GENERIC:
-        break;
-      case UNINITIALIZED:
-      case PREMONOMORPHIC:
-      case MONOMORPHIC_PROTOTYPE_FAILURE:
-      case DEBUG_STUB:
-        UNREACHABLE();
-        break;
+      break;
     }
+    case MEGAMORPHIC:
+    case GENERIC:
+      break;
+    case UNINITIALIZED:
+    case PREMONOMORPHIC:
+    case MONOMORPHIC_PROTOTYPE_FAILURE:
+    case DEBUG_STUB:
+      UNREACHABLE();
+      break;
   }
 }
 
@@ -1192,6 +1195,9 @@ Handle<Code> KeyedLoadIC::LoadElementStub(Handle<JSObject> receiver) {
     target_receiver_maps.Add(isolate()->factory()->string_map());
   } else {
     GetReceiverMapsForStub(Handle<Code>(target()), &target_receiver_maps);
+    if (target_receiver_maps.length() == 0) {
+      return isolate()->stub_cache()->ComputeKeyedLoadElement(receiver_map);
+    }
   }
 
   // The first time a receiver is seen that is a transitioned version of the
@@ -1564,6 +1570,13 @@ Handle<Code> KeyedStoreIC::StoreElementStub(Handle<JSObject> receiver,
   }
 
   GetReceiverMapsForStub(Handle<Code>(target()), &target_receiver_maps);
+  if (target_receiver_maps.length() == 0) {
+    // Optimistically assume that ICs that haven't reached the MONOMORPHIC state
+    // yet will do so and stay there.
+    stub_kind = GetNoTransitionStubKind(stub_kind);
+    return isolate()->stub_cache()->ComputeKeyedStoreElement(
+        receiver_map, stub_kind, strict_mode, grow_mode);
+  }
   // The first time a receiver is seen that is a transitioned version of the
   // previous monomorphic receiver type, assume the new ElementsKind is the
   // monomorphic type. This benefits global arrays that only transition

test/mjsunit/regress/regress-crbug-172345.js

+// Copyright 2013 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+function f(a,i) {
+  return a[i];
+}
+
+f([1,2,3], "length");
+f([1,2,3], "length");
+f([1,2,3], 2);