1 /* -----------------------------------------------------------------------------
3 * (c) The GHC Team, 1998-2004
7 * ---------------------------------------------------------------------------*/
12 /* -----------------------------------------------------------------------------
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:
18 - if the closure being updated is a blocking queue, then all the
19 threads waiting on the blocking queue are updated.
21 - then the lower level updateWithIndirection() macro is invoked
22 to actually replace the closure with an indirection (see below).
24 -------------------------------------------------------------------------- */
27 # define UPD_IND(updclosure, heapptr) \
28 UPD_REAL_IND(updclosure,INFO_PTR(stg_IND_info),heapptr,SEMI)
29 # define UPD_SPEC_IND(updclosure, ind_info, heapptr, and_then) \
30 UPD_REAL_IND(updclosure,ind_info,heapptr,and_then)
32 /* These macros have to work in both C and C--, so here's the
38 #define INFO_PTR(info) info
42 #define INFO_PTR(info) &info
43 #define StgBlockingQueue_blocking_queue(closure) \
44 (((StgBlockingQueue *)closure)->blocking_queue)
47 /* krc: there used to be an UPD_REAL_IND and an
48 UPD_PERM_IND, the latter of which was used for
49 ticky and cost-centre profiling.
50 for now, we just have UPD_REAL_IND. */
51 #define UPD_REAL_IND(updclosure, ind_info, heapptr, and_then) \
53 updateWithIndirection(ind_info, \
59 /* -----------------------------------------------------------------------------
60 Awaken any threads waiting on a blocking queue (BLACKHOLE_BQ).
61 -------------------------------------------------------------------------- */
63 /* -----------------------------------------------------------------------------
64 Updates: lower-level macros which update a closure with an
65 indirection to another closure.
67 There are several variants of this code.
70 -------------------------------------------------------------------------- */
73 * We call LDV_recordDead_FILL_SLOP_DYNAMIC(p1) regardless of the generation in
77 * After all, we do *NOT* need to call LDV_RECORD_CREATE() for both IND and
78 * IND_OLDGEN closures because they are inherently used. But, it corrupts
79 * the invariants that every closure keeps its creation time in the profiling
80 * field. So, we call LDV_RECORD_CREATE().
83 /* In the DEBUG case, we also zero out the slop of the old closure,
84 * so that the sanity checker can tell where the next closure is.
86 * Two important invariants: we should never try to update a closure
87 * to point to itself, and the closure being updated should not
88 * already have been updated (the mutable list will get messed up
91 * NB. We do *not* do this in THREADED_RTS mode, because when we have the
92 * possibility of multiple threads entering the same closure, zeroing
93 * the slop in one of the threads would have a disastrous effect on
94 * the other (seen in the wild!).
98 #define FILL_SLOP(p) \
102 inf = %GET_STD_INFO(p); \
103 if (%INFO_TYPE(inf) != HALF_W_(BLACKHOLE) \
104 && %INFO_TYPE(inf) != HALF_W_(CAF_BLACKHOLE)) { \
105 if (%INFO_TYPE(inf) == HALF_W_(THUNK_SELECTOR)) { \
106 sz = BYTES_TO_WDS(SIZEOF_StgSelector_NoThunkHdr); \
108 if (%INFO_TYPE(inf) == HALF_W_(AP_STACK)) { \
109 sz = StgAP_STACK_size(p) + BYTES_TO_WDS(SIZEOF_StgAP_STACK_NoThunkHdr); \
111 if (%INFO_TYPE(inf) == HALF_W_(AP)) { \
112 sz = TO_W_(StgAP_n_args(p)) + BYTES_TO_WDS(SIZEOF_StgAP_NoThunkHdr); \
114 sz = TO_W_(%INFO_PTRS(inf)) + TO_W_(%INFO_NPTRS(inf)); \
121 StgThunk_payload(p,i) = 0; \
127 #else /* !CMINUSMINUS */
130 FILL_SLOP(StgClosure *p)
132 StgInfoTable *inf = get_itbl(p);
139 // we already filled in the slop when we overwrote the thunk
140 // with BLACKHOLE, and also an evacuated BLACKHOLE is only the
143 sz = sizeofW(StgSelector) - sizeofW(StgThunkHeader);
146 sz = ((StgAP *)p)->n_args + sizeofW(StgAP) - sizeofW(StgThunkHeader);
149 sz = ((StgAP_STACK *)p)->size + sizeofW(StgAP_STACK) - sizeofW(StgThunkHeader);
152 sz = inf->layout.payload.ptrs + inf->layout.payload.nptrs;
155 for (i = 0; i < sz; i++) {
156 ((StgThunk *)p)->payload[i] = 0;
162 #endif /* CMINUSMINUS */
164 #if !defined(DEBUG) || defined(THREADED_RTS)
165 #define DEBUG_FILL_SLOP(p) /* do nothing */
167 #define DEBUG_FILL_SLOP(p) FILL_SLOP(p)
170 /* We have two versions of this macro (sadly), one for use in C-- code,
171 * and the other for C.
173 * The and_then argument is a performance hack so that we can paste in
174 * the continuation code directly. It helps shave a couple of
175 * instructions off the common case in the update code, which is
176 * worthwhile (the update code is often part of the inner loop).
177 * (except that gcc now appears to common up this code again and
178 * invert the optimisation. Grrrr --SDM).
181 #define generation(n) (W_[generations] + n*SIZEOF_generation)
182 #define updateWithIndirection(ind_info, p1, p2, and_then) \
185 DEBUG_FILL_SLOP(p1); \
186 LDV_RECORD_DEAD_FILL_SLOP_DYNAMIC(p1); \
187 StgInd_indirectee(p1) = p2; \
188 prim %write_barrier() []; \
190 if (bdescr_gen_no(bd) != 0 :: CInt) { \
191 recordMutableCap(p1, TO_W_(bdescr_gen_no(bd)), R1); \
192 SET_INFO(p1, stg_IND_OLDGEN_info); \
193 LDV_RECORD_CREATE(p1); \
194 TICK_UPD_OLD_IND(); \
197 SET_INFO(p1, ind_info); \
198 LDV_RECORD_CREATE(p1); \
199 TICK_UPD_NEW_IND(); \
203 #define updateWithIndirection(ind_info, p1, p2, and_then) \
207 ASSERT( (P_)p1 != (P_)p2 ); \
208 /* not necessarily true: ASSERT( !closure_IND(p1) ); */ \
209 /* occurs in RaiseAsync.c:raiseAsync() */ \
210 DEBUG_FILL_SLOP(p1); \
211 LDV_RECORD_DEAD_FILL_SLOP_DYNAMIC(p1); \
212 ((StgInd *)p1)->indirectee = p2; \
214 bd = Bdescr((P_)p1); \
215 if (bd->gen_no != 0) { \
216 recordMutableGenLock(p1, bd->gen_no); \
217 SET_INFO(p1, &stg_IND_OLDGEN_info); \
218 TICK_UPD_OLD_IND(); \
221 SET_INFO(p1, ind_info); \
222 LDV_RECORD_CREATE(p1); \
223 TICK_UPD_NEW_IND(); \
227 #endif /* CMINUSMINUS */
228 #endif /* UPDATES_H */