1 /* -----------------------------------------------------------------------------
2 * $Id: Updates.h,v 1.6 1999/01/21 10:31:45 simonm Exp $
4 * Definitions related to updates.
6 * ---------------------------------------------------------------------------*/
11 /* -----------------------------------------------------------------------------
12 Update a closure with an indirection. This may also involve waking
13 up a queue of blocked threads waiting on the result of this
15 -------------------------------------------------------------------------- */
17 /* ToDo: overwrite slop words with something safe in case sanity checking
19 * (I think the fancy version of the GC is supposed to do this too.)
22 /* This expands to a fair chunk of code, what with waking up threads
23 * and checking whether we're updating something in a old generation.
24 * preferably don't use this macro inline in compiled code.
27 #define UPD_IND(updclosure, heapptr) \
28 AWAKEN_BQ(updclosure); \
29 updateWithIndirection((StgClosure *)updclosure, \
30 (StgClosure *)heapptr);
32 /* -----------------------------------------------------------------------------
33 Awaken any threads waiting on this computation
34 -------------------------------------------------------------------------- */
36 extern void awaken_blocked_queue(StgTSO *q);
38 #define AWAKEN_BQ(closure) \
39 if (closure->header.info == &BLACKHOLE_BQ_info) { \
40 StgTSO *bq = ((StgBlockingQueue *)closure)->blocking_queue;\
41 if (bq != (StgTSO *)&END_TSO_QUEUE_closure) { \
42 STGCALL1(awaken_blocked_queue, bq); \
47 /* -----------------------------------------------------------------------------
48 Push an update frame on the stack.
49 -------------------------------------------------------------------------- */
51 #if defined(PROFILING)
52 #define PUSH_STD_CCCS(frame) frame->header.prof.ccs = CCCS
54 #define PUSH_STD_CCCS(frame)
57 extern const StgPolyInfoTable Upd_frame_info;
59 #define PUSH_UPD_FRAME(target, Sp_offset) \
61 StgUpdateFrame *__frame; \
63 __frame = stgCast(StgUpdateFrame*,Sp + (Sp_offset)) - 1; \
64 SET_INFO(__frame,stgCast(StgInfoTable*,&Upd_frame_info)); \
66 __frame->updatee = (StgClosure *)(target); \
67 PUSH_STD_CCCS(__frame); \
71 /* -----------------------------------------------------------------------------
74 When a CAF is first entered, it creates a black hole in the heap,
75 and updates itself with an indirection to this new black hole.
77 We update the CAF with an indirection to a newly-allocated black
78 hole in the heap. We also set the blocking queue on the newly
79 allocated black hole to be empty.
81 Why do we make a black hole in the heap when we enter a CAF?
83 - for a generational garbage collector, which needs a fast
84 test for whether an updatee is in an old generation or not
86 - for the parallel system, which can implement updates more
87 easily if the updatee is always in the heap. (allegedly).
89 When debugging, we maintain a separate CAF list so we can tell when
90 a CAF has been garbage collected.
91 -------------------------------------------------------------------------- */
93 /* ToDo: only call newCAF when debugging. */
95 extern void newCAF(StgClosure*);
97 #define UPD_CAF(cafptr, bhptr) \
99 SET_INFO((StgInd *)cafptr,&IND_STATIC_info); \
100 ((StgInd *)cafptr)->indirectee = (StgClosure *)(bhptr); \
101 STGCALL1(newCAF,(StgClosure *)cafptr); \
104 /* -----------------------------------------------------------------------------
105 Update-related prototypes
106 -------------------------------------------------------------------------- */
108 extern STGFUN(Upd_frame_entry);
110 extern const StgInfoTable PAP_info;
113 EXTFUN(stg_update_PAP);
115 extern const StgInfoTable AP_UPD_info;
116 STGFUN(AP_UPD_entry);
118 extern const StgInfoTable raise_info;
120 #endif /* UPDATES_H */