mono/sgen/sgen-scan-object.h

   1 /**
   2  * \file
   3  * Generic object scan.
   4  *
   5  * Copyright 2001-2003 Ximian, Inc
   6  * Copyright 2003-2010 Novell, Inc.
   7  * Copyright (C) 2013 Xamarin Inc
   8  *
   9  * Licensed under the MIT license. See LICENSE file in the project root for full license information.
  10  *
  11  *
  12  * Scans one object, using the OBJ_XXX macros.  The start of the
  13  * object must be given in the variable "char* start".  Afterwards,
  14  * "start" will point to the start of the next object, if the scanned
  15  * object contained references.  If not, the value of "start" should
  16  * be considered undefined after executing this code.  The object's
  17  * GC descriptor must be in the variable "mword desc".
  18  *
  19  * The macro `HANDLE_PTR` will be invoked for every reference encountered while scanning the
  20  * object.  It is called with two parameters: The pointer to the reference (not the
  21  * reference itself!) as well as the pointer to the scanned object.
  22  *
  23  * Modifiers (automatically undefined):
  24  *
  25  * SCAN_OBJECT_NOSCAN - if defined, don't actually scan the object,
  26  * i.e. don't invoke the OBJ_XXX macros.
  27  *
  28  * SCAN_OBJECT_NOVTABLE - desc is provided by the includer, instead of
  29  * vt.  Complex arrays cannot not be scanned.
  30  *
  31  * SCAN_OBJECT_PROTOCOL - if defined, binary protocol the scan.
  32  * Should only be used for scanning that's done for the actual
  33  * collection, not for debugging scans.
  34  */
  35
  36 {
  37 #ifndef SCAN_OBJECT_NOVTABLE
  38 #if defined(SGEN_HEAVY_BINARY_PROTOCOL) && defined(SCAN_OBJECT_PROTOCOL)
  39         sgen_binary_protocol_scan_begin ((GCObject*)start, SGEN_LOAD_VTABLE ((GCObject*)start), sgen_safe_object_get_size ((GCObject*)start));
  40 #endif
  41 #else
  42 #if defined(SGEN_HEAVY_BINARY_PROTOCOL) && defined(SCAN_OBJECT_PROTOCOL)
  43         sgen_binary_protocol_scan_vtype_begin (start + SGEN_CLIENT_OBJECT_HEADER_SIZE, size);
  44 #endif
  45 #endif
  46         switch (desc & DESC_TYPE_MASK) {
  47         case DESC_TYPE_RUN_LENGTH:
  48 #define SCAN OBJ_RUN_LEN_FOREACH_PTR (desc, ((GCObject*)start))
  49 #ifndef SCAN_OBJECT_NOSCAN
  50                 SCAN;
  51 #endif
  52 #undef SCAN
  53                 break;
  54         case DESC_TYPE_VECTOR:
  55 #define SCAN OBJ_VECTOR_FOREACH_PTR (desc, ((GCObject*)start))
  56 #ifndef SCAN_OBJECT_NOSCAN
  57                 SCAN;
  58 #endif
  59 #undef SCAN
  60                 break;
  61         case DESC_TYPE_BITMAP:
  62 #define SCAN OBJ_BITMAP_FOREACH_PTR (desc, ((GCObject*)start))
  63 #ifndef SCAN_OBJECT_NOSCAN
  64                 SCAN;
  65 #endif
  66 #undef SCAN
  67                 break;
  68         case DESC_TYPE_COMPLEX:
  69                 /* this is a complex object */
  70 #define SCAN OBJ_COMPLEX_FOREACH_PTR (desc, ((GCObject*)start))
  71 #ifndef SCAN_OBJECT_NOSCAN
  72                 SCAN;
  73 #endif
  74 #undef SCAN
  75                 break;
  76 #ifndef SCAN_OBJECT_NOVTABLE
  77         case DESC_TYPE_COMPLEX_ARR:
  78                 /* this is an array of complex structs */
  79 #define SCAN OBJ_COMPLEX_ARR_FOREACH_PTR (desc, ((GCObject*)start))
  80 #ifndef SCAN_OBJECT_NOSCAN
  81                 SCAN;
  82 #endif
  83 #undef SCAN
  84                 break;
  85 #endif
  86         case DESC_TYPE_SMALL_PTRFREE:
  87         case DESC_TYPE_COMPLEX_PTRFREE:
  88                 /*Nothing to do*/
  89                 break;
  90         default:
  91                 g_assert_not_reached ();
  92         }
  93 }
  94
  95 #undef SCAN_OBJECT_NOSCAN
  96 #undef SCAN_OBJECT_NOVTABLE
  97 #undef SCAN_OBJECT_PROTOCOL