hphp/runtime/vm/pc-filter.h

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010-2013 Facebook, Inc. (http://www.facebook.com)     |
   6    | Copyright (c) 1997-2010 The PHP Group                                |
   7    +----------------------------------------------------------------------+
   8    | This source file is subject to version 3.01 of the PHP license,      |
   9    | that is bundled with this package in the file LICENSE, and is        |
  10    | available through the world-wide-web at the following url:           |
  11    | http://www.php.net/license/3_01.txt                                  |
  12    | If you did not receive a copy of the PHP license and are unable to   |
  13    | obtain it through the world-wide-web, please send a note to          |
  14    | license@php.net so we can mail you a copy immediately.               |
  15    +----------------------------------------------------------------------+
  16 */
  17
  18 #ifndef incl_HPHP_PC_FILTER_H_
  19 #define incl_HPHP_PC_FILTER_H_
  20
  21 #include "hphp/runtime/vm/unit.h"
  22
  23 namespace HPHP {
  24 ////////////////////////////////////////////////////////////////////////////////
  25
  26 // Map which holds a set of PCs and supports reasonably fast addition and
  27 // lookup. Used to decide if a given PC falls within an interesting area, e.g.,
  28 // for breakpoints and stepping.
  29 class PCFilter {
  30 private:
  31   // Radix-tree implementation of pointer map
  32   struct PtrMapNode;
  33   class PtrMap {
  34 #define PTRMAP_PTR_SIZE       (sizeof(void*) * 8)
  35 #define PTRMAP_LEVEL_BITS     8LL
  36 #define PTRMAP_LEVEL_ENTRIES  (1LL << PTRMAP_LEVEL_BITS)
  37 #define PTRMAP_LEVEL_MASK     (PTRMAP_LEVEL_ENTRIES - 1LL)
  38
  39   public:
  40     PtrMap() {
  41       static_assert(PTRMAP_PTR_SIZE % PTRMAP_LEVEL_BITS == 0,
  42                     "PTRMAP_PTR_SIZE must be a multiple of PTRMAP_LEVEL_BITS");
  43       m_root = MakeNode();
  44     }
  45     ~PtrMap();
  46     void setPointer(void* ptr, void* val);
  47     void* getPointer(void* ptr);
  48     void clear();
  49
  50   private:
  51     PtrMapNode* m_root;
  52     static PtrMapNode* MakeNode();
  53   };
  54
  55   PtrMap m_map;
  56
  57 public:
  58   PCFilter() {}
  59
  60   // Filter function to exclude opcodes when adding ranges.
  61   typedef std::function<bool(Op)> OpcodeFilter;
  62
  63   // Add/remove offsets, either individually or by range. By default allow all
  64   // opcodes.
  65   void addRanges(const Unit* unit, const OffsetRangeVec& offsets,
  66                  OpcodeFilter isOpcodeAllowed = [] (Op) { return true; });
  67   void removeRanges(const Unit* unit, const OffsetRangeVec& offsets,
  68                     OpcodeFilter isOpcodeAllowed = [] (Op) { return true; });
  69   void removeOffset(const Unit* unit, Offset offset);
  70
  71   // Add/remove/check explicit PCs.
  72   void addPC(const unsigned char* pc) {
  73     m_map.setPointer((void*)pc, (void*)pc);
  74   }
  75   void removePC(const unsigned char* pc) {
  76     m_map.setPointer((void*)pc, nullptr);
  77   }
  78   bool checkPC(const unsigned char* pc) {
  79     return m_map.getPointer((void*)pc) == (void*)pc;
  80   }
  81
  82   void clear() {
  83     m_map.clear();
  84   }
  85 };
  86
  87 ///////////////////////////////////////////////////////////////////////////////
  88 }
  89
  90 #endif // incl_HPHP_PC_FILTER_H_