hphp/runtime/vm/jit/edge.h

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010-2014 Facebook, Inc. (http://www.facebook.com)     |
   6    +----------------------------------------------------------------------+
   7    | This source file is subject to version 3.01 of the PHP license,      |
   8    | that is bundled with this package in the file LICENSE, and is        |
   9    | available through the world-wide-web at the following url:           |
  10    | http://www.php.net/license/3_01.txt                                  |
  11    | If you did not receive a copy of the PHP license and are unable to   |
  12    | obtain it through the world-wide-web, please send a note to          |
  13    | license@php.net so we can mail you a copy immediately.               |
  14    +----------------------------------------------------------------------+
  15 */
  16
  17 #ifndef incl_HPHP_VM_EDGE_H_
  18 #define incl_HPHP_VM_EDGE_H_
  19
  20 #include <boost/intrusive/list.hpp>
  21 #include <boost/noncopyable.hpp>
  22
  23 namespace HPHP { namespace JIT {
  24
  25 struct Block;
  26 struct IRInstruction;
  27
  28 /*
  29  * An Edge represents a control-flow edge as an encapsulated pointer to a
  30  * successor block that maintains a list of predecessors of each block.
  31  * The predecessor list is updated by calling setTo().
  32  */
  33 struct Edge : private boost::noncopyable {
  34   Edge() : m_to(nullptr), m_inst(nullptr) {}
  35   Edge(const Edge& other) : m_to(nullptr), m_inst(nullptr) {
  36     setTo(other.m_to);
  37   }
  38   explicit Edge(IRInstruction* inst, Block* to) : m_to(nullptr), m_inst(inst) {
  39     setTo(to);
  40   }
  41
  42   // The instruction that owns this edge
  43   IRInstruction* inst() const { return m_inst; }
  44   void setInst(IRInstruction* inst) { m_inst = inst; };
  45
  46   // The block this edge takes us to.  Changing this property updates
  47   // the affected Block's preds property.
  48   Block* to() const { return m_to; }
  49   void setTo(Block* to);
  50
  51   // set the to field but don't update any predecessor lists. Only used
  52   // for transient instructions.
  53   void setTransientTo(Block* to) {
  54     m_to = to;
  55   }
  56
  57   // Use to/from accessors to access or mutate pointers
  58   Edge& operator=(const Edge& other) = delete;
  59
  60  private:
  61   Block* m_to;
  62   IRInstruction* m_inst;
  63  public:
  64   boost::intrusive::list_member_hook<> m_node; // for Block::m_preds
  65 };
  66
  67 typedef boost::intrusive::member_hook<Edge,
  68                                       boost::intrusive::list_member_hook<>,
  69                                       &Edge::m_node>
  70         EdgeHookOption;
  71 typedef boost::intrusive::list<Edge, EdgeHookOption> EdgeList;
  72
  73 }}
  74
  75 #endif