include/jitcs_memmgr.h

   1 //===-- jitcs_memmgr.h - A memory manager for code and data -----*- C++ -*-===//
   2 //
   3 // The manager is an allocator based on Doug Leah's malloc. Memory is allocated
   4 // from the system with execution permission.
   5 // TODO:
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef _JITCS_MEMMGR_H_
  10 #define _JITCS_MEMMGR_H_
  11
  12 #include "jitcs_base.h"
  13 #include "jitcs_adt_refcounter.h"
  14 #include "jitcs_adt_slice.h"
  15 #include <memory>
  16
  17 namespace jitcs {
  18 class MemoryMgrImpl;
  19
  20 class MemoryMgr {
  21 public:
  22   struct CodeAndData {
  23     Slice<u8> data, code;
  24   };
  25 public:
  26   static RefCounter<MemoryMgr> Create();
  27 protected:
  28   MemoryMgr();
  29   ~MemoryMgr();
  30
  31 public:
  32   /* todo
  33    * allocate area for function relevant constants (aligned to 16 byte)
  34    * allocate area for code (aligned to cache line size, currently 64 byte)
  35    * allocated areas are stored in a function object, function objects can be forced to free allocated storage
  36    */
  37   CodeAndData allocate(size_t data, size_t code);
  38   CodeAndData shortenAllocation(CodeAndData, size_t data, size_t code);
  39   void deallocate(CodeAndData);
  40
  41   bool check();
  42   size_t getTotalSpace();
  43   size_t getAllocatedSpace();
  44   size_t getFreeSpace();
  45   size_t getReachableFreeSpace();
  46   bool shrink();
  47
  48 private:
  49   // called from RefCounter
  50   friend class RefCounter<MemoryMgr>;
  51   void _incRef() { ++_refCnt; }
  52   void _decRef() { if (!--_refCnt) _release(); }
  53   void _release();
  54
  55 private:
  56   std::unique_ptr<MemoryMgrImpl> _mgr;
  57   size_t _refCnt;
  58 };
  59
  60 } // end of namespace jitcs
  61
  62 #endif
  63 // _JITCS_MEMMGR_H_