Fix background compilation queue access. Some cleanups.

runtime/vm/intermediate_language.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/intermediate_language.h"
 
 #include "vm/bit_vector.h"
 #include "vm/bootstrap.h"
 #include "vm/compiler.h"
 #include "vm/constant_propagator.h"
@@ skipping 73 matching lines @@
 
 
 const ICData* Instruction::GetICData(
     const ZoneGrowableArray<const ICData*>& ic_data_array) const {
   // The deopt_id can be outside the range of the IC data array for
   // computations added in the optimizing compiler.
   ASSERT(deopt_id_ != Thread::kNoDeoptId);
   if (deopt_id_ < ic_data_array.length()) {
     const ICData* result = ic_data_array[deopt_id_];
 #if defined(TAG_IC_DATA)
-    if (result->tag() == -1) {
-      result->set_tag(tag());
-    } else if (result->tag() != tag()) {
-      FATAL("ICData tag mismatch");
+    if (result != NULL) {
+      if (result->tag() == -1) {
+        result->set_tag(tag());
+      } else if (result->tag() != tag()) {
+        FATAL("ICData tag mismatch");
+      }
     }
 #endif
     return result;
   }
   return NULL;
 }
 
 
 intptr_t Instruction::Hashcode() const {
   intptr_t result = tag();
@@ skipping 3651 matching lines @@
   set_native_c_function(native_function);
   function().SetIsNativeAutoSetupScope(auto_setup_scope);
   Dart_NativeEntryResolver resolver = library.native_entry_resolver();
   bool is_bootstrap_native = Bootstrap::IsBootstapResolver(resolver);
   set_is_bootstrap_native(is_bootstrap_native);
 }
 
 #undef __
 
 }  // namespace dart