ghc/includes/Updates.h

   1 /* -----------------------------------------------------------------------------
   2  *
   3  * (c) The GHC Team, 1998-2004
   4  *
   5  * Performing updates.
   6  *
   7  * ---------------------------------------------------------------------------*/
   8
   9 #ifndef UPDATES_H
  10 #define UPDATES_H
  11
  12 /* -----------------------------------------------------------------------------
  13    Updates
  14
  15    We have two layers of update macros.  The top layer, UPD_IND() and
  16    friends perform all the work of an update.  In detail:
  17
  18       - if the closure being updated is a blocking queue, then all the
  19         threads waiting on the blocking queue are updated.
  20
  21       - then the lower level updateWithIndirection() macro is invoked
  22         to actually replace the closure with an indirection (see below).
  23
  24    -------------------------------------------------------------------------- */
  25
  26 #ifdef TICKY_TICKY
  27 # define UPD_IND(updclosure, heapptr) \
  28    UPD_PERM_IND(updclosure,heapptr)
  29 # define UPD_SPEC_IND(updclosure, ind_info, heapptr, and_then) \
  30    UPD_PERM_IND(updclosure,heapptr); and_then
  31 #else
  32 #  define SEMI ;
  33 # define UPD_IND(updclosure, heapptr) \
  34    UPD_REAL_IND(updclosure,INFO_PTR(stg_IND_info),heapptr,SEMI)
  35 # define UPD_SPEC_IND(updclosure, ind_info, heapptr, and_then) \
  36    UPD_REAL_IND(updclosure,ind_info,heapptr,and_then)
  37 #endif
  38
  39 /* These macros have to work in both C and C--, so here's the
  40  * impedence matching:
  41  */
  42 #ifdef CMINUSMINUS
  43 #define BLOCK_BEGIN
  44 #define BLOCK_END
  45 #define DECLARE_IPTR(info)  W_ info
  46 #define FCALL               foreign "C"
  47 #define INFO_PTR(info)      info
  48 #define ARG_PTR             "ptr"
  49 #else
  50 #define BLOCK_BEGIN         {
  51 #define BLOCK_END           }
  52 #define DECLARE_IPTR(info)  const StgInfoTable *(info)
  53 #define FCALL               /* nothing */
  54 #define INFO_PTR(info)      &info
  55 #define StgBlockingQueue_blocking_queue(closure) \
  56     (((StgBlockingQueue *)closure)->blocking_queue)
  57 #define ARG_PTR             /* nothing */
  58 #endif
  59
  60 /* UPD_IND actually does a PERM_IND if TICKY_TICKY is on;
  61    if you *really* need an IND use UPD_REAL_IND
  62  */
  63 #define UPD_REAL_IND(updclosure, ind_info, heapptr, and_then)   \
  64         BLOCK_BEGIN                                             \
  65         DECLARE_IPTR(info);                                     \
  66         info = GET_INFO(updclosure);                            \
  67         AWAKEN_BQ(info,updclosure);                             \
  68         updateWithIndirection(GET_INFO(updclosure), ind_info,   \
  69                               updclosure,                       \
  70                               heapptr,                          \
  71                               and_then);                        \
  72         BLOCK_END
  73
  74 #if defined(PROFILING) || defined(TICKY_TICKY)
  75 #define UPD_PERM_IND(updclosure, heapptr)       \
  76         BLOCK_BEGIN                             \
  77         DECLARE_IPTR(info);                     \
  78         info = GET_INFO(updclosure);            \
  79         AWAKEN_BQ(info,updclosure);             \
  80         updateWithPermIndirection(info,         \
  81                                   updclosure,   \
  82                                   heapptr);     \
  83         BLOCK_END
  84 #endif
  85
  86 #if defined(RTS_SUPPORTS_THREADS)
  87
  88 # ifdef TICKY_TICKY
  89 #  define UPD_IND_NOLOCK(updclosure, heapptr)   \
  90         BLOCK_BEGIN                             \
  91         DECLARE_IPTR(info);                     \
  92         info = GET_INFO(updclosure);            \
  93         AWAKEN_BQ_NOLOCK(info,updclosure);      \
  94         updateWithPermIndirection(info,         \
  95                                   updclosure,   \
  96                                   heapptr);     \
  97         BLOCK_END
  98 # else
  99 #  define UPD_IND_NOLOCK(updclosure, heapptr)                   \
 100         BLOCK_BEGIN                                             \
 101         DECLARE_IPTR(info);                                     \
 102         info = GET_INFO(updclosure);                            \
 103         AWAKEN_BQ_NOLOCK(info,updclosure);                      \
 104         updateWithIndirection(info, INFO_PTR(stg_IND_info),     \
 105                               updclosure,                       \
 106                               heapptr,);                        \
 107         BLOCK_END
 108 # endif
 109
 110 #else
 111 #define UPD_IND_NOLOCK(updclosure,heapptr) UPD_IND(updclosure,heapptr)
 112 #endif
 113
 114 /* -----------------------------------------------------------------------------
 115    Awaken any threads waiting on a blocking queue (BLACKHOLE_BQ).
 116    -------------------------------------------------------------------------- */
 117
 118 #if defined(PAR)
 119
 120 /*
 121    In a parallel setup several types of closures might have a blocking queue:
 122      BLACKHOLE_BQ ... same as in the default concurrent setup; it will be
 123                       reawakened via calling UPD_IND on that closure after
 124                       having finished the computation of the graph
 125      FETCH_ME_BQ  ... a global indirection (FETCH_ME) may be entered by a
 126                       local TSO, turning it into a FETCH_ME_BQ; it will be
 127                       reawakened via calling processResume
 128      RBH          ... a revertible black hole may be entered by another
 129                       local TSO, putting it onto its blocking queue; since
 130                       RBHs only exist while the corresponding closure is in
 131                       transit, they will be reawakened via calling
 132                       convertToFetchMe (upon processing an ACK message)
 133
 134    In a parallel setup a blocking queue may contain 3 types of closures:
 135      TSO           ... as in the default concurrent setup
 136      BLOCKED_FETCH ... indicating that a TSO on another PE is waiting for
 137                        the result of the current computation
 138      CONSTR        ... an RBHSave closure (which contains data ripped out of
 139                        the closure to make room for a blocking queue; since
 140                        it only contains data we use the exisiting type of
 141                        a CONSTR closure); this closure is the end of a
 142                        blocking queue for an RBH closure; it only exists in
 143                        this kind of blocking queue and must be at the end
 144                        of the queue
 145 */
 146 extern void awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node);
 147 #define DO_AWAKEN_BQ(bqe, node)  STGCALL2(awakenBlockedQueue, bqe, node);
 148
 149 #define AWAKEN_BQ(info,closure)                                         \
 150         if (info == &stg_BLACKHOLE_BQ_info ||               \
 151             info == &stg_FETCH_ME_BQ_info ||                \
 152             get_itbl(closure)->type == RBH) {                           \
 153                 DO_AWAKEN_BQ(((StgBlockingQueue *)closure)->blocking_queue, closure);                           \
 154         }
 155
 156 #elif defined(GRAN)
 157
 158 extern void awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node);
 159 #define DO_AWAKEN_BQ(bq, node)  STGCALL2(awakenBlockedQueue, bq, node);
 160
 161 /* In GranSim we don't have FETCH_ME or FETCH_ME_BQ closures, so they are
 162    not checked. The rest of the code is the same as for GUM.
 163 */
 164 #define AWAKEN_BQ(info,closure)                                         \
 165         if (info == &stg_BLACKHOLE_BQ_info ||               \
 166             get_itbl(closure)->type == RBH) {                           \
 167                 DO_AWAKEN_BQ(((StgBlockingQueue *)closure)->blocking_queue, closure);                           \
 168         }
 169
 170
 171 #else /* !GRAN && !PAR */
 172
 173 #define DO_AWAKEN_BQ(closure)   \
 174         FCALL awakenBlockedQueue(StgBlockingQueue_blocking_queue(closure) ARG_PTR);
 175
 176 #define AWAKEN_BQ(info,closure)                                         \
 177         if (info == INFO_PTR(stg_BLACKHOLE_BQ_info)) {                  \
 178           DO_AWAKEN_BQ(closure);                                        \
 179         }
 180
 181 #define AWAKEN_STATIC_BQ(info,closure)                                  \
 182         if (info == INFO_PTR(stg_BLACKHOLE_BQ_STATIC_info)) {           \
 183           DO_AWAKEN_BQ(closure);                                        \
 184         }
 185
 186 #ifdef RTS_SUPPORTS_THREADS
 187 #define DO_AWAKEN_BQ_NOLOCK(closure) \
 188         FCALL awakenBlockedQueueNoLock(StgBlockingQueue_blocking_queue(closure) ARG_PTR);
 189
 190 #define AWAKEN_BQ_NOLOCK(info,closure)                                  \
 191         if (info == INFO_PTR(stg_BLACKHOLE_BQ_info)) {                  \
 192           DO_AWAKEN_BQ_NOLOCK(closure);                                 \
 193         }
 194 #endif
 195 #endif /* GRAN || PAR */
 196
 197 /* -----------------------------------------------------------------------------
 198    Updates: lower-level macros which update a closure with an
 199    indirection to another closure.
 200
 201    There are several variants of this code.
 202
 203        PROFILING:
 204    -------------------------------------------------------------------------- */
 205
 206 /* LDV profiling:
 207  * We call LDV_recordDead_FILL_SLOP_DYNAMIC(p1) regardless of the generation in
 208  * which p1 resides.
 209  *
 210  * Note:
 211  *   After all, we do *NOT* need to call LDV_RECORD_CREATE() for both IND and
 212  *   IND_OLDGEN closures because they are inherently used. But, it corrupts
 213  *   the invariants that every closure keeps its creation time in the profiling
 214  *  field. So, we call LDV_RECORD_CREATE().
 215  */
 216
 217 /* In the DEBUG case, we also zero out the slop of the old closure,
 218  * so that the sanity checker can tell where the next closure is.
 219  *
 220  * Two important invariants: we should never try to update a closure
 221  * to point to itself, and the closure being updated should not
 222  * already have been updated (the mutable list will get messed up
 223  * otherwise).
 224  */
 225 #if !defined(DEBUG)
 226
 227 #define DEBUG_FILL_SLOP(p) /* nothing */
 228
 229 #else  /* DEBUG */
 230
 231 #ifdef CMINUSMINUS
 232
 233 #define DEBUG_FILL_SLOP(p)                      \
 234   W_ inf;                                       \
 235   W_ np;                                        \
 236   W_ nw;                                        \
 237   W_ i;                                         \
 238   inf = %GET_STD_INFO(p);                       \
 239   np = TO_W_(%INFO_PTRS(inf));                  \
 240   nw = TO_W_(%INFO_NPTRS(inf));                 \
 241   if (%INFO_TYPE(inf) != HALF_W_(THUNK_SELECTOR)) {     \
 242     i = 0;                                      \
 243     for:                                        \
 244       if (i < np + nw) {                        \
 245         StgClosure_payload(p,i) = 0;            \
 246         i = i + 1;                              \
 247         goto for;                               \
 248       }                                         \
 249   }
 250
 251
 252 #else /* !CMINUSMINUS */
 253
 254 INLINE_HEADER void
 255 DEBUG_FILL_SLOP(StgClosure *p)
 256 {
 257     StgInfoTable *inf = get_itbl(p);
 258     nat np = inf->layout.payload.ptrs,
 259         nw = inf->layout.payload.nptrs, i;
 260     if (inf->type != THUNK_SELECTOR) {
 261         for (i = 0; i < np + nw; i++) {
 262             ((StgClosure *)p)->payload[i] = 0;
 263         }
 264     }
 265 }
 266
 267 #endif /* CMINUSMINUS */
 268 #endif /* DEBUG */
 269
 270 /* We have two versions of this macro (sadly), one for use in C-- code,
 271  * and the other for C.
 272  *
 273  * The and_then argument is a performance hack so that we can paste in
 274  * the continuation code directly.  It helps shave a couple of
 275  * instructions off the common case in the update code, which is
 276  * worthwhile (the update code is often part of the inner loop).
 277  * (except that gcc now appears to common up this code again and
 278  * invert the optimisation.  Grrrr --SDM).
 279  */
 280 #ifdef CMINUSMINUS
 281 #define generation(n) (W_[generations] + n*SIZEOF_generation)
 282 #define updateWithIndirection(info, ind_info, p1, p2, and_then) \
 283     W_ bd;                                                      \
 284                                                                 \
 285 /*    ASSERT( p1 != p2 && !closure_IND(p1) );                   \
 286  */ LDV_RECORD_DEAD_FILL_SLOP_DYNAMIC(p1);                      \
 287     bd = Bdescr(p1);                                            \
 288     if (bdescr_gen_no(bd) == 0 :: CInt) {                       \
 289       StgInd_indirectee(p1) = p2;                               \
 290       SET_INFO(p1, ind_info);                                   \
 291       LDV_RECORD_CREATE(p1);                                    \
 292       TICK_UPD_NEW_IND();                                       \
 293       and_then;                                                 \
 294     } else {                                                    \
 295       if (info != stg_BLACKHOLE_BQ_info) {                      \
 296         DEBUG_FILL_SLOP(p1);                                    \
 297         foreign "C" recordMutableGen(p1 "ptr",                  \
 298                  generation(TO_W_(bdescr_gen_no(bd))) "ptr");   \
 299       }                                                         \
 300       StgInd_indirectee(p1) = p2;                               \
 301       SET_INFO(p1, stg_IND_OLDGEN_info);                        \
 302       LDV_RECORD_CREATE(p1);                                    \
 303       TICK_UPD_OLD_IND();                                       \
 304       and_then;                                                 \
 305   }
 306 #else
 307 #define updateWithIndirection(_info, ind_info, p1, p2, and_then)        \
 308   {                                                                     \
 309     bdescr *bd;                                                         \
 310                                                                         \
 311     ASSERT( (P_)p1 != (P_)p2 && !closure_IND(p1) );                     \
 312     LDV_RECORD_DEAD_FILL_SLOP_DYNAMIC(p1);                              \
 313     bd = Bdescr((P_)p1);                                                \
 314     if (bd->gen_no == 0) {                                              \
 315       ((StgInd *)p1)->indirectee = p2;                                  \
 316       SET_INFO(p1, ind_info);                                           \
 317       LDV_RECORD_CREATE(p1);                                            \
 318       TICK_UPD_NEW_IND();                                               \
 319       and_then;                                                         \
 320     } else {                                                            \
 321       if (_info != &stg_BLACKHOLE_BQ_info) {                            \
 322         DEBUG_FILL_SLOP(p1);                                            \
 323         recordMutableGen(p1, &generations[bd->gen_no]);                 \
 324       }                                                                 \
 325       ((StgInd *)p1)->indirectee = p2;                                  \
 326       SET_INFO(p1, &stg_IND_OLDGEN_info);                               \
 327       TICK_UPD_OLD_IND();                                               \
 328       and_then;                                                         \
 329     }                                                                   \
 330   }
 331 #endif
 332
 333 /* The permanent indirection version isn't performance critical.  We
 334  * therefore use an inline C function instead of the C-- macro.
 335  */
 336 #ifndef CMINUSMINUS
 337 INLINE_HEADER void
 338 updateWithPermIndirection(const StgInfoTable *info,
 339                           StgClosure *p1,
 340                           StgClosure *p2)
 341 {
 342   bdescr *bd;
 343
 344   ASSERT( p1 != p2 && !closure_IND(p1) );
 345
 346   // @LDV profiling
 347   // Destroy the old closure.
 348   // Nb: LDV_* stuff cannot mix with ticky-ticky
 349   LDV_RECORD_DEAD_FILL_SLOP_DYNAMIC(p1);
 350
 351   bd = Bdescr((P_)p1);
 352   if (bd->gen_no == 0) {
 353     ((StgInd *)p1)->indirectee = p2;
 354     SET_INFO(p1, &stg_IND_PERM_info);
 355     // @LDV profiling
 356     // We have just created a new closure.
 357     LDV_RECORD_CREATE(p1);
 358     TICK_UPD_NEW_PERM_IND(p1);
 359   } else {
 360     if (info != &stg_BLACKHOLE_BQ_info) {
 361         recordMutableGen(p1, &generations[bd->gen_no]);
 362     }
 363     ((StgInd *)p1)->indirectee = p2;
 364     SET_INFO(p1, &stg_IND_OLDGEN_PERM_info);
 365     // @LDV profiling
 366     // We have just created a new closure.
 367     LDV_RECORD_CREATE(p1);
 368     TICK_UPD_OLD_PERM_IND();
 369   }
 370 }
 371 #endif
 372
 373 #endif /* UPDATES_H */