1 /* ----------------------------------------------------------------------------
3 * (c) The GHC Team, 1998-2004
7 * -------------------------------------------------------------------------- */
9 #ifndef RTS_STORAGE_CLOSURES_H
10 #define RTS_STORAGE_CLOSURES_H
13 * The Layout of a closure header depends on which kind of system we're
14 * compiling for: profiling, parallel, ticky, etc.
17 /* -----------------------------------------------------------------------------
19 -------------------------------------------------------------------------- */
24 struct _RetainerSet *rs; /* Retainer Set */
25 StgWord ldvw; /* Lag/Drag/Void Word */
29 /* -----------------------------------------------------------------------------
32 A thunk has a padding word to take the updated value. This is so
33 that the update doesn't overwrite the payload, so we can avoid
34 needing to lock the thunk during entry and update.
36 Note: this doesn't apply to THUNK_STATICs, which have no payload.
38 Note: we leave this padding word in all ways, rather than just SMP,
39 so that we don't have to recompile all our libraries for SMP.
40 -------------------------------------------------------------------------- */
46 /* -----------------------------------------------------------------------------
47 The full fixed-size closure header
49 The size of the fixed header is the sum of the optional parts plus a single
50 word for the entry code pointer.
51 -------------------------------------------------------------------------- */
54 const StgInfoTable* info;
61 const StgInfoTable* info;
65 StgSMPThunkHeader smp;
68 #define THUNK_EXTRA_HEADER_W (sizeofW(StgThunkHeader)-sizeofW(StgHeader))
70 /* -----------------------------------------------------------------------------
73 For any given closure type (defined in InfoTables.h), there is a
74 corresponding structure defined below. The name of the structure
75 is obtained by concatenating the closure type with '_closure'
76 -------------------------------------------------------------------------- */
78 /* All closures follow the generic format */
80 typedef struct StgClosure_ {
82 struct StgClosure_ *payload[FLEXIBLE_ARRAY];
83 } *StgClosurePtr; // StgClosure defined in Rts.h
86 StgThunkHeader header;
87 struct StgClosure_ *payload[FLEXIBLE_ARRAY];
91 StgThunkHeader header;
97 StgHalfWord arity; /* zero if it is an AP */
99 StgClosure *fun; /* really points to a fun */
100 StgClosure *payload[FLEXIBLE_ARRAY];
104 StgThunkHeader header;
105 StgHalfWord arity; /* zero if it is an AP */
107 StgClosure *fun; /* really points to a fun */
108 StgClosure *payload[FLEXIBLE_ARRAY];
112 StgThunkHeader header;
113 StgWord size; /* number of words in payload */
115 StgClosure *payload[FLEXIBLE_ARRAY]; /* contains a chunk of *stack* */
120 StgClosure *indirectee;
125 StgClosure *indirectee;
126 StgClosure *static_link;
127 const StgInfoTable *saved_info;
130 typedef struct StgBlockingQueue_ {
132 struct StgBlockingQueue_ *link; // here so it looks like an IND
133 StgClosure *bh; // the BLACKHOLE
135 struct MessageBlackHole_ *queue;
141 StgWord payload[FLEXIBLE_ARRAY];
147 StgWord size; // ptrs plus card table
148 StgClosure *payload[FLEXIBLE_ARRAY];
149 // see also: StgMutArrPtrs macros in ClosureMacros.h
157 typedef struct _StgUpdateFrame {
164 StgWord exceptions_blocked;
169 const StgInfoTable* info;
170 struct StgStack_ *next_chunk;
180 } StgIntCharlikeClosure;
182 /* statically allocated */
187 typedef struct _StgStableName {
192 typedef struct _StgWeak { /* Weak v */
194 StgClosure *cfinalizer;
196 StgClosure *value; /* v */
197 StgClosure *finalizer;
198 struct _StgWeak *link;
201 typedef struct _StgDeadWeak { /* Weak v */
203 struct _StgWeak *link;
206 /* Byte code objects. These are fixed size objects with pointers to
207 * four arrays, designed so that a BCO can be easily "re-linked" to
208 * other BCOs, to facilitate GHC's intelligent recompilation. The
209 * array of instructions is static and not re-generated when the BCO
210 * is re-linked, but the other 3 arrays will be regenerated.
212 * A BCO represents either a function or a stack frame. In each case,
213 * it needs a bitmap to describe to the garbage collector the
214 * pointerhood of its arguments/free variables respectively, and in
215 * the case of a function it also needs an arity. These are stored
216 * directly in the BCO, rather than in the instrs array, for two
218 * (a) speed: we need to get at the bitmap info quickly when
219 * the GC is examining APs and PAPs that point to this BCO
220 * (b) a subtle interaction with the compacting GC. In compacting
221 * GC, the info that describes the size/layout of a closure
222 * cannot be in an object more than one level of indirection
223 * away from the current object, because of the order in
224 * which pointers are updated to point to their new locations.
229 StgArrWords *instrs; /* a pointer to an ArrWords */
230 StgArrWords *literals; /* a pointer to an ArrWords */
231 StgMutArrPtrs *ptrs; /* a pointer to a MutArrPtrs */
232 StgHalfWord arity; /* arity of this BCO */
233 StgHalfWord size; /* size of this BCO (in words) */
234 StgWord bitmap[FLEXIBLE_ARRAY]; /* an StgLargeBitmap */
237 #define BCO_BITMAP(bco) ((StgLargeBitmap *)((StgBCO *)(bco))->bitmap)
238 #define BCO_BITMAP_SIZE(bco) (BCO_BITMAP(bco)->size)
239 #define BCO_BITMAP_BITS(bco) (BCO_BITMAP(bco)->bitmap)
240 #define BCO_BITMAP_SIZEW(bco) ((BCO_BITMAP_SIZE(bco) + BITS_IN(StgWord) - 1) \
243 /* -----------------------------------------------------------------------------
244 Dynamic stack frames for generic heap checks.
246 These generic heap checks are slow, but have the advantage of being
247 usable in a variety of situations.
249 The one restriction is that any relevant SRTs must already be pointed
250 to from the stack. The return address doesn't need to have an info
251 table attached: hence it can be any old code pointer.
253 The liveness mask contains a 1 at bit n, if register Rn contains a
254 non-pointer. The contents of all 8 vanilla registers are always saved
255 on the stack; the liveness mask tells the GC which ones contain
258 Good places to use a generic heap check:
260 - case alternatives (the return address with an SRT is already
263 - primitives (no SRT required).
265 The stack frame layout for a RET_DYN is like this:
267 some pointers |-- RET_DYN_PTRS(liveness) words
268 some nonpointers |-- RET_DYN_NONPTRS(liveness) words
271 D1-2 |-- RET_DYN_NONPTR_REGS_SIZE words
274 R1-8 |-- RET_DYN_BITMAP_SIZE words
277 liveness mask |-- StgRetDyn structure
280 we assume that the size of a double is always 2 pointers (wasting a
281 word when it is only one pointer, but avoiding lots of #ifdefs).
283 See Liveness.h for the macros (RET_DYN_PTRS() etc.).
285 NOTE: if you change the layout of RET_DYN stack frames, then you
286 might also need to adjust the value of RESERVED_STACK_WORDS in
288 -------------------------------------------------------------------------- */
291 const StgInfoTable* info;
294 StgClosure * payload[FLEXIBLE_ARRAY];
297 /* A function return stack frame: used when saving the state for a
298 * garbage collection at a function entry point. The function
299 * arguments are on the stack, and we also save the function (its
300 * info table describes the pointerhood of the arguments).
302 * The stack frame size is also cached in the frame for convenience.
305 const StgInfoTable* info;
308 StgClosure * payload[FLEXIBLE_ARRAY];
311 /* Concurrent communication objects */
313 typedef struct StgMVarTSOQueue_ {
315 struct StgMVarTSOQueue_ *link;
321 struct StgMVarTSOQueue_ *head;
322 struct StgMVarTSOQueue_ *tail;
327 /* STM data structures
329 * StgTVar defines the only type that can be updated through the STM
332 * Note that various optimisations may be possible in order to use less
333 * space for these data structures at the cost of more complexity in the
336 * - In StgTVar, current_value and first_watch_queue_entry could be held in
337 * the same field: if any thread is waiting then its expected_value for
338 * the tvar is the current value.
340 * - In StgTRecHeader, it might be worthwhile having separate chunks
341 * of read-only and read-write locations. This would save a
342 * new_value field in the read-only locations.
344 * - In StgAtomicallyFrame, we could combine the waiting bit into
345 * the header (maybe a different info tbl for a waiting transaction).
346 * This means we can specialise the code for the atomically frame
347 * (it immediately switches on frame->waiting anyway).
350 typedef struct StgTRecHeader_ StgTRecHeader;
352 typedef struct StgTVarWatchQueue_ {
354 StgClosure *closure; // StgTSO or StgAtomicInvariant
355 struct StgTVarWatchQueue_ *next_queue_entry;
356 struct StgTVarWatchQueue_ *prev_queue_entry;
361 StgClosure *volatile current_value;
362 StgTVarWatchQueue *volatile first_watch_queue_entry;
363 #if defined(THREADED_RTS)
364 StgInt volatile num_updates;
371 StgTRecHeader *last_execution;
373 } StgAtomicInvariant;
375 /* new_value == expected_value for read-only accesses */
376 /* new_value is a StgTVarWatchQueue entry when trec in state TREC_WAITING */
379 StgClosure *expected_value;
380 StgClosure *new_value;
381 #if defined(THREADED_RTS)
386 #define TREC_CHUNK_NUM_ENTRIES 16
388 typedef struct StgTRecChunk_ {
390 struct StgTRecChunk_ *prev_chunk;
391 StgWord next_entry_idx;
392 TRecEntry entries[TREC_CHUNK_NUM_ENTRIES];
396 TREC_ACTIVE, /* Transaction in progress, outcome undecided */
397 TREC_CONDEMNED, /* Transaction in progress, inconsistent / out of date reads */
398 TREC_COMMITTED, /* Transaction has committed, now updating tvars */
399 TREC_ABORTED, /* Transaction has aborted, now reverting tvars */
400 TREC_WAITING, /* Transaction currently waiting */
403 typedef struct StgInvariantCheckQueue_ {
405 StgAtomicInvariant *invariant;
406 StgTRecHeader *my_execution;
407 struct StgInvariantCheckQueue_ *next_queue_entry;
408 } StgInvariantCheckQueue;
410 struct StgTRecHeader_ {
412 struct StgTRecHeader_ *enclosing_trec;
413 StgTRecChunk *current_chunk;
414 StgInvariantCheckQueue *invariants_to_check;
421 StgTVarWatchQueue *next_invariant_to_check;
423 } StgAtomicallyFrame;
433 StgBool running_alt_code;
434 StgClosure *first_code;
435 StgClosure *alt_code;
436 } StgCatchRetryFrame;
438 /* ----------------------------------------------------------------------------
440 ------------------------------------------------------------------------- */
442 typedef struct Message_ {
444 struct Message_ *link;
447 typedef struct MessageWakeup_ {
453 typedef struct MessageThrowTo_ {
455 struct MessageThrowTo_ *link;
458 StgClosure *exception;
461 typedef struct MessageBlackHole_ {
463 struct MessageBlackHole_ *link;
468 #endif /* RTS_STORAGE_CLOSURES_H */