text: /*
     +----------------------------------------------------------------------+
     | HipHop for PHP                                                       |
     +----------------------------------------------------------------------+
     | Copyright (c) 2010-present Facebook, Inc. (http://www.facebook.com)  |
     +----------------------------------------------------------------------+
     | This source file is subject to version 3.01 of the PHP license,      |
     | that is bundled with this package in the file LICENSE, and is        |
     | available through the world-wide-web at the following url:           |
     | http://www.php.net/license/3_01.txt                                  |
     | If you did not receive a copy of the PHP license and are unable to   |
     | obtain it through the world-wide-web, please send a note to          |
     | license@php.net so we can mail you a copy immediately.               |
     +----------------------------------------------------------------------+
  */
  
  #ifndef incl_HPHP_VM_GUARD_CONSTRAINTS_H_
  #define incl_HPHP_VM_GUARD_CONSTRAINTS_H_
  
  #include "hphp/runtime/vm/jit/containers.h"
  #include "hphp/runtime/vm/jit/type-constraint.h"
  #include "hphp/runtime/vm/jit/type-source.h"
  #include "hphp/runtime/vm/jit/type.h"
  
  namespace HPHP { namespace jit {
  
  struct IRInstruction;
  
  /*
   * GuardConstraints holds state that is collected during initial IR generation
   * and needed by the guard relaxation pass.
   */
  struct GuardConstraints {
    /*
     * Maps guard instructions (CheckLoc, CheckStk, etc.) to TypeConstraints. The
     * TypeConstraints for a guard start out fully generic and are tightened
     * appropriately when a value's type is used.
     */
    jit::hash_map<const IRInstruction*, TypeConstraint> guards;
  
    /*
     * Maps certain instructions dealing with locals to the source of the
     * local's type coming into the instruction: usually either a guard or the
     * last known value of the local.
     */
    jit::hash_map<const IRInstruction*, TypeSourceSet> typeSrcs;
  
    /*
     * Maps AssertLoc/CheckLoc instructions to the type of the local coming into
     * the instruction. It is needed to compute the type of the local after the
     * guard.
     */
    jit::hash_map<const IRInstruction*, Type> prevTypes;
  };
  
  }}
  
  #endif
  