Track prologue offset of Code and use for more precise return addresses

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"
@@ skipping 61 matching lines @@
   static const int kCallPattern[kLengthInBytes] = {0xE8, -1, -1, -1, -1};
   return kCallPattern;
 }
 
 
 const int* ReturnPattern::pattern() const {
   static const int kReturnPattern[kLengthInBytes] = { 0xC3 };
   return kReturnPattern;
 }
 
+
+const int* ProloguePattern::pattern() const {
+  static const int kProloguePattern[kLengthInBytes] =
+      { 0x55, 0x48, 0x89, 0xe5 };
+  return kProloguePattern;
+}
+
+
+const int* SetFramePointerPattern::pattern() const {
+  static const int kFramePointerPattern[kLengthInBytes] = { 0x48, 0x89, 0xe5 };
+  return kFramePointerPattern;
+}
+
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64