Fix debugger stub patching on x64 architecture

runtime/vm/instructions_x64.cc

 // Copyright (c) 2012, 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/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/cpu.h"
 #include "vm/instructions.h"
 #include "vm/object.h"
 
 namespace dart {
 
 intptr_t InstructionPattern::IndexFromPPLoad(uword start) {
   int32_t offset = *reinterpret_cast<int32_t*>(start);
   offset += kHeapObjectTag;
   return (offset - Array::data_offset()) / kWordSize;
 }
 
 
+intptr_t InstructionPattern::OffsetFromPPIndex(intptr_t index) {
+  intptr_t offset = Array::element_offset(index);
+  return offset - kHeapObjectTag;
+}
+
+
 bool InstructionPattern::TestBytesWith(const int* data, int num_bytes) const {
   ASSERT(data != NULL);
   const uint8_t* byte_array = reinterpret_cast<const uint8_t*>(start_);
   for (int i = 0; i < num_bytes; i++) {
     // Skip comparison for data[i] < 0.
     if ((data[i] >= 0) && (byte_array[i] != (0xFF & data[i]))) {
       return false;
     }
   }
   return true;
@@ skipping 55 matching lines @@
 
 
 const int* ShortCallPattern::pattern() const {
   static const int kCallPattern[kLengthInBytes] = {0xE8, -1, -1, -1, -1};
   return kCallPattern;
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64