ghc/includes/Updates.h

   1 /* -----------------------------------------------------------------------------
   2  * $Id: Updates.h,v 1.28 2002/12/11 15:36:40 simonmar Exp $
   3  *
   4  * (c) The GHC Team, 1998-1999
   5  *
   6  * Definitions related to updates.
   7  *
   8  * ---------------------------------------------------------------------------*/
   9
  10 #ifndef UPDATES_H
  11 #define UPDATES_H
  12
  13 /* -----------------------------------------------------------------------------
  14    Update a closure with an indirection.  This may also involve waking
  15    up a queue of blocked threads waiting on the result of this
  16    computation.
  17    -------------------------------------------------------------------------- */
  18
  19 /* ToDo: overwrite slop words with something safe in case sanity checking
  20  *       is turned on.
  21  *       (I think the fancy version of the GC is supposed to do this too.)
  22  */
  23
  24 /* This expands to a fair chunk of code, what with waking up threads
  25  * and checking whether we're updating something in a old generation.
  26  * preferably don't use this macro inline in compiled code.
  27  */
  28
  29 #ifdef TICKY_TICKY
  30 # define UPD_IND(updclosure, heapptr) UPD_PERM_IND(updclosure,heapptr)
  31 #else
  32 # define UPD_IND(updclosure, heapptr) UPD_REAL_IND(updclosure,heapptr)
  33 #endif
  34
  35 /* UPD_IND actually does a PERM_IND if TICKY_TICKY is on;
  36    if you *really* need an IND use UPD_REAL_IND
  37  */
  38 #ifdef SMP
  39 #define UPD_REAL_IND(updclosure, heapptr)                               \
  40    {                                                                    \
  41         const StgInfoTable *info;                                       \
  42         if (Bdescr((P_)updclosure)->u.back != (bdescr *)BaseReg) {      \
  43                 info = LOCK_CLOSURE(updclosure);                        \
  44         } else {                                                        \
  45                 info = updclosure->header.info;                         \
  46         }                                                               \
  47         AWAKEN_BQ(info,updclosure);                                     \
  48         updateWithIndirection(info,                                     \
  49                               (StgClosure *)updclosure,                 \
  50                               (StgClosure *)heapptr);                   \
  51    }
  52 #else
  53 #define UPD_REAL_IND(updclosure, heapptr)               \
  54    {                                                    \
  55         const StgInfoTable *info;                       \
  56         info = ((StgClosure *)updclosure)->header.info; \
  57         AWAKEN_BQ(info,updclosure);                     \
  58         updateWithIndirection(info,                     \
  59                               (StgClosure *)updclosure, \
  60                               (StgClosure *)heapptr);   \
  61    }
  62 #endif
  63
  64 #define UPD_STATIC_IND(updclosure, heapptr)                     \
  65    {                                                            \
  66         const StgInfoTable *info;                               \
  67         info = ((StgClosure *)updclosure)->header.info;         \
  68         AWAKEN_STATIC_BQ(info,updclosure);                      \
  69         updateWithStaticIndirection(info,                       \
  70                                     (StgClosure *)updclosure,   \
  71                                     (StgClosure *)heapptr);     \
  72    }
  73
  74 #if defined(PROFILING) || defined(TICKY_TICKY)
  75 #define UPD_PERM_IND(updclosure, heapptr)                       \
  76    {                                                            \
  77         const StgInfoTable *info;                               \
  78         info = ((StgClosure *)updclosure)->header.info;         \
  79         AWAKEN_BQ(info,updclosure);                             \
  80         updateWithPermIndirection(info,                         \
  81                                   (StgClosure *)updclosure,     \
  82                                   (StgClosure *)heapptr);       \
  83    }
  84 #endif
  85
  86 #ifdef SMP
  87 #define UPD_IND_NOLOCK(updclosure, heapptr)                             \
  88    {                                                                    \
  89         const StgInfoTable *info;                                       \
  90         info = updclosure->header.info;                                 \
  91         AWAKEN_BQ(info,updclosure);                                     \
  92         updateWithIndirection(info,                                     \
  93                               (StgClosure *)updclosure,                 \
  94                               (StgClosure *)heapptr);                   \
  95    }
  96 #else
  97 #define UPD_IND_NOLOCK(updclosure,heapptr) UPD_IND(updclosure,heapptr)
  98 #endif
  99
 100 /* -----------------------------------------------------------------------------
 101    Awaken any threads waiting on this computation
 102    -------------------------------------------------------------------------- */
 103
 104 #if defined(PAR)
 105
 106 /*
 107    In a parallel setup several types of closures might have a blocking queue:
 108      BLACKHOLE_BQ ... same as in the default concurrent setup; it will be
 109                       reawakened via calling UPD_IND on that closure after
 110                       having finished the computation of the graph
 111      FETCH_ME_BQ  ... a global indirection (FETCH_ME) may be entered by a
 112                       local TSO, turning it into a FETCH_ME_BQ; it will be
 113                       reawakened via calling processResume
 114      RBH          ... a revertible black hole may be entered by another
 115                       local TSO, putting it onto its blocking queue; since
 116                       RBHs only exist while the corresponding closure is in
 117                       transit, they will be reawakened via calling
 118                       convertToFetchMe (upon processing an ACK message)
 119
 120    In a parallel setup a blocking queue may contain 3 types of closures:
 121      TSO           ... as in the default concurrent setup
 122      BLOCKED_FETCH ... indicating that a TSO on another PE is waiting for
 123                        the result of the current computation
 124      CONSTR        ... an RBHSave closure (which contains data ripped out of
 125                        the closure to make room for a blocking queue; since
 126                        it only contains data we use the exisiting type of
 127                        a CONSTR closure); this closure is the end of a
 128                        blocking queue for an RBH closure; it only exists in
 129                        this kind of blocking queue and must be at the end
 130                        of the queue
 131 */
 132 extern void awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node);
 133 #define DO_AWAKEN_BQ(bqe, node)  STGCALL2(awakenBlockedQueue, bqe, node);
 134
 135 #define AWAKEN_BQ(info,closure)                                         \
 136         if (info == &stg_BLACKHOLE_BQ_info ||               \
 137             info == &stg_FETCH_ME_BQ_info ||                \
 138             get_itbl(closure)->type == RBH) {                           \
 139                 DO_AWAKEN_BQ(((StgBlockingQueue *)closure)->blocking_queue, closure);                           \
 140         }
 141
 142 #elif defined(GRAN)
 143
 144 extern void awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node);
 145 #define DO_AWAKEN_BQ(bq, node)  STGCALL2(awakenBlockedQueue, bq, node);
 146
 147 /* In GranSim we don't have FETCH_ME or FETCH_ME_BQ closures, so they are
 148    not checked. The rest of the code is the same as for GUM.
 149 */
 150 #define AWAKEN_BQ(info,closure)                                         \
 151         if (info == &stg_BLACKHOLE_BQ_info ||               \
 152             get_itbl(closure)->type == RBH) {                           \
 153                 DO_AWAKEN_BQ(((StgBlockingQueue *)closure)->blocking_queue, closure);                           \
 154         }
 155
 156
 157 #else /* !GRAN && !PAR */
 158
 159 extern void awakenBlockedQueue(StgTSO *q);
 160 #define DO_AWAKEN_BQ(closure)   \
 161         STGCALL1(awakenBlockedQueue,            \
 162                  ((StgBlockingQueue *)closure)->blocking_queue);
 163
 164 #define AWAKEN_BQ(info,closure)                                         \
 165         if (info == &stg_BLACKHOLE_BQ_info) {                           \
 166           DO_AWAKEN_BQ(closure);                                        \
 167         }
 168
 169 #define AWAKEN_STATIC_BQ(info,closure)                                  \
 170         if (info == &stg_BLACKHOLE_BQ_STATIC_info) {                    \
 171           DO_AWAKEN_BQ(closure);                                        \
 172         }
 173
 174 #endif /* GRAN || PAR */
 175
 176 /* -------------------------------------------------------------------------
 177    Push an update frame on the stack.
 178    ------------------------------------------------------------------------- */
 179
 180 #if defined(PROFILING)
 181 // frame->header.prof.hp.rs = NULL (or frame-header.prof.hp.ldvw = 0) is unnecessary
 182 // because it is not used anyhow.
 183 #define PUSH_STD_CCCS(frame) (frame->header.prof.ccs = CCCS)
 184 #else
 185 #define PUSH_STD_CCCS(frame)
 186 #endif
 187
 188 extern DLL_IMPORT_RTS const StgPolyInfoTable stg_upd_frame_info;
 189 extern DLL_IMPORT_RTS const StgPolyInfoTable stg_noupd_frame_info;
 190
 191 #define PUSH_UPD_FRAME(target, Sp_offset)                       \
 192         {                                                       \
 193                 StgUpdateFrame *__frame;                        \
 194                 TICK_UPDF_PUSHED(target, GET_INFO((StgClosure*)target)); \
 195                 __frame = (StgUpdateFrame *)(Sp + (Sp_offset)) - 1; \
 196                 SET_INFO(__frame, (StgInfoTable *)&stg_upd_frame_info);   \
 197                 __frame->updatee = (StgClosure *)(target);      \
 198                 PUSH_STD_CCCS(__frame);                         \
 199         }
 200
 201 /* -----------------------------------------------------------------------------
 202    Entering CAFs
 203
 204    When a CAF is first entered, it creates a black hole in the heap,
 205    and updates itself with an indirection to this new black hole.
 206
 207    We update the CAF with an indirection to a newly-allocated black
 208    hole in the heap.  We also set the blocking queue on the newly
 209    allocated black hole to be empty.
 210
 211    Why do we make a black hole in the heap when we enter a CAF?
 212
 213        - for a  generational garbage collector, which needs a fast
 214          test for whether an updatee is in an old generation or not
 215
 216        - for the parallel system, which can implement updates more
 217          easily if the updatee is always in the heap. (allegedly).
 218
 219    When debugging, we maintain a separate CAF list so we can tell when
 220    a CAF has been garbage collected.
 221    -------------------------------------------------------------------------- */
 222
 223 /* ToDo: only call newCAF when debugging. */
 224
 225 extern void newCAF(StgClosure*);
 226
 227 /* newCAF must be called before the itbl ptr is overwritten, since
 228    newCAF records the old itbl ptr in order to do CAF reverting
 229    (which Hugs needs to do in order that combined mode works right.)
 230 */
 231 #define UPD_CAF(cafptr, bhptr)                                          \
 232   {                                                                     \
 233     LOCK_CLOSURE(cafptr);                                               \
 234     STGCALL1(newCAF,(StgClosure *)cafptr);                              \
 235     ((StgInd *)cafptr)->indirectee   = (StgClosure *)(bhptr);           \
 236     SET_INFO((StgInd *)cafptr,(const StgInfoTable*)&stg_IND_STATIC_info);\
 237   }
 238
 239 /* -----------------------------------------------------------------------------
 240    Update-related prototypes
 241    -------------------------------------------------------------------------- */
 242
 243 #endif /* UPDATES_H */