X87: Only dynamically perform access checks on the receiver if it's a JSGlobalProxy.

src/ic/x87/handler-compiler-x87.cc

Index: src/ic/x87/handler-compiler-x87.cc
diff --git a/src/ic/x87/handler-compiler-x87.cc b/src/ic/x87/handler-compiler-x87.cc
index 2eb10c3a3bce9bfc32e51dd755f9b8286d02cad9..f64e7d8f0d083aba5d7ceef18e7412c04e731f79 100644
--- a/src/ic/x87/handler-compiler-x87.cc
+++ b/src/ic/x87/handler-compiler-x87.cc
@@ -431,6 +431,17 @@ Register PropertyHandlerCompiler::CheckPrototypes(
   if (receiver_map->IsJSGlobalObjectMap()) {
     current = isolate()->global_object();
   }
+
+  // Check access rights to the global object.  This has to happen after
+  // the map check so that we know that the object is actually a global
+  // object.
+  // This allows us to install generated handlers for accesses to the
+  // global proxy (as opposed to using slow ICs). See corresponding code
+  // in LookupForRead().
+  if (receiver_map->IsJSGlobalProxyMap()) {
+    __ CheckAccessGlobalProxy(reg, scratch1, scratch2, miss);
+  }
+
   Handle<JSObject> prototype = Handle<JSObject>::null();
   Handle<Map> current_map = receiver_map;
   Handle<Map> holder_map(holder()->map());
@@ -471,17 +482,7 @@ Register PropertyHandlerCompiler::CheckPrototypes(
         __ j(not_equal, miss);
       }
 
-      // Check access rights to the global object.  This has to happen after
-      // the map check so that we know that the object is actually a global
-      // object.
-      // This allows us to install generated handlers for accesses to the
-      // global proxy (as opposed to using slow ICs). See corresponding code
-      // in LookupForRead().
-      if (current_map->IsJSGlobalProxyMap()) {
-        __ CheckAccessGlobalProxy(reg, map_reg, scratch2, miss);
-        // Restore map_reg.
-        __ mov(map_reg, FieldOperand(reg, HeapObject::kMapOffset));
-      } else if (current_map->IsJSGlobalObjectMap()) {
+      if (current_map->IsJSGlobalObjectMap()) {
         GenerateCheckPropertyCell(masm(), Handle<JSGlobalObject>::cast(current),
                                   name, scratch2, miss);
       }
@@ -505,13 +506,6 @@ Register PropertyHandlerCompiler::CheckPrototypes(
     __ j(not_equal, miss);
   }
 
-  // Perform security check for access to the global object.
-  DCHECK(current_map->IsJSGlobalProxyMap() ||
-         !current_map->is_access_check_needed());
-  if (current_map->IsJSGlobalProxyMap()) {
-    __ CheckAccessGlobalProxy(reg, scratch1, scratch2, miss);
-  }
-
   // Return the register containing the holder.
   return reg;
 }