include/AD/gc/gcintern.h

   1 //////////////////////////////////////////////////////////////////////////////
   2 // NOTICE:
   3 //
   4 // ADLib, Prop and their related set of tools and documentation are in the
   5 // public domain.   The author(s) of this software reserve no copyrights on
   6 // the source code and any code generated using the tools.  You are encouraged
   7 // to use ADLib and Prop to develop software, in both academic and commercial
   8 // settings, and are welcomed to incorporate any part of ADLib and Prop into
   9 // your programs.
  10 //
  11 // Although you are under no obligation to do so, we strongly recommend that
  12 // you give away all software developed using our tools.
  13 //
  14 // We also ask that credit be given to us when ADLib and/or Prop are used in
  15 // your programs, and that this notice be preserved intact in all the source
  16 // code.
  17 //
  18 // This software is still under development and we welcome(read crave for)
  19 // any suggestions and help from the users.
  20 //
  21 // Allen Leung (leunga@cs.nyu.edu)
  22 // 1994
  23 //////////////////////////////////////////////////////////////////////////////
  24
  25 #ifndef garbage_collector_internals_h
  26 #define garbage_collector_internals_h
  27
  28 #include <new.h>
  29
  30 //////////////////////////////////////////////////////////////////////////////
  31 //  Some opaque forward definitions
  32 //////////////////////////////////////////////////////////////////////////////
  33 class GCObject;  // garbage collectable objects
  34 class GC;        // garbage collectors
  35 class BGC;       // Barlett's mostly copying garbage collector
  36
  37 //////////////////////////////////////////////////////////////////////////////
  38 //  Object headers definitions.
  39 //  The object header has the following format:
  40 //  For copying collectors:
  41 //     Bit 0     -- the forward bit.
  42 //     Bit 1-31  -- If this is 1 then bit 1 - 31 is the forwarding address.
  43 //                  Otherwise, bit 1 - 31 is the length of the object in bytes,
  44 //                  *including* the length of the header and any other
  45 //                  alignment needs.
  46 //  For marksweep collectors:
  47 //     Bit 0     -- the freelist bit; object in the free list has this
  48 //                  bit set.
  49 //     Bit 1-31  -- the length of the object with header info.
  50 //////////////////////////////////////////////////////////////////////////////
  51 typedef unsigned long GCHeader;
  52
  53 //////////////////////////////////////////////////////////////////////////////
  54 //  Macros for manipulating headers.
  55 // GC_OBJ_HEADER_ADDR(obj) --- return the address of the header given an object
  56 // GC_OBJ_HEADER(obj)      --- return the header given an object address
  57 // GC_OBJ_OBJECT_ADDR(ptr) --- return the object address given a header address
  58 // GC_OBJ_HEADER_LEN(h)    --- return the object length given a header
  59 // GC_OBJ_IS_FORWARDED(h)  --- test if a header is forwarded
  60 // GC_OBJ_FORWARD_ADDR(h)  --- return the forwarded address of a header
  61 // GC_OBJ_SET_FORWARD(obj,ptr) --- set the header to a forwarded address
  62 // GC_OBJ_SET_HEADER(obj,len)  --- set a normal header with an object length
  63 //////////////////////////////////////////////////////////////////////////////
  64 #define GC_OBJ_HEADER_ADDR(obj) (((GCHeader*)(obj))-1)
  65 #define GC_OBJ_HEADER(obj)      (*GC_OBJ_HEADER_ADDR(obj))
  66 #define GC_OBJ_OBJECT_ADDR(ptr) ((GCObject*)(((GCHeader*)(ptr))+1))
  67 #define GC_OBJ_HEADER_LEN(h)    (h)
  68 #define GC_OBJ_IS_FORWARDED(h)  ((h) & 0x1)
  69 #define GC_OBJ_FORWARD_ADDR(h)  ((GCObject*)((h) & 0xfffffffe))
  70 #define GC_OBJ_SET_FORWARD(obj,ptr) \
  71    (GC_OBJ_HEADER(obj) = ((GCHeader)(ptr) | 0x1))
  72 #define GC_OBJ_SET_HEADER(obj,len)  (GC_OBJ_HEADER(obj) = len)
  73 #define GC_OBJ_FREELIST_LEN(h)       ((h) & 0xfffffffe)
  74 #define GC_OBJ_SET_FREELIST(obj,len) (GC_OBJ_HEADER(obj) = ((len) & 0x1))
  75 #define GC_OBJ_IS_ON_FREELIST(h)     ((h) & 0x1)
  76
  77 #endif