1 /* ----------------------------------------------------------------------------
3 * (c) The GHC Team, 1998-2004
7 * -------------------------------------------------------------------------- */
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 /* -----------------------------------------------------------------------------
31 -------------------------------------------------------------------------- */
34 StgWord procs; /* bitmask indicating on which PEs this closure resides */
37 /* -----------------------------------------------------------------------------
38 The full fixed-size closure header
40 The size of the fixed header is the sum of the optional parts plus a single
41 word for the entry code pointer.
42 -------------------------------------------------------------------------- */
45 const struct _StgInfoTable* info;
54 /* -----------------------------------------------------------------------------
57 For any given closure type (defined in InfoTables.h), there is a
58 corresponding structure defined below. The name of the structure
59 is obtained by concatenating the closure type with '_closure'
60 -------------------------------------------------------------------------- */
62 /* All closures follow the generic format */
66 struct StgClosure_ *payload[FLEXIBLE_ARRAY];
76 StgHalfWord arity; /* zero if it is an AP */
78 StgClosure *fun; /* really points to a fun */
79 StgClosure *payload[FLEXIBLE_ARRAY];
82 /* AP closures have the same layout, for convenience */
87 StgWord size; /* number of words in payload */
89 StgClosure *payload[FLEXIBLE_ARRAY]; /* contains a chunk of *stack* */
94 StgClosure *indirectee;
99 StgClosure *indirectee;
100 StgClosure *static_link;
101 struct _StgInfoTable *saved_info;
107 StgWord payload[FLEXIBLE_ARRAY];
113 StgClosure *payload[FLEXIBLE_ARRAY];
121 typedef struct _StgUpdateFrame {
128 StgInt exceptions_blocked;
144 } StgIntCharlikeClosure;
146 /* statically allocated */
151 typedef struct _StgForeignObj {
153 StgAddr data; /* pointer to data in non-haskell-land */
156 typedef struct _StgStableName {
161 typedef struct _StgWeak { /* Weak v */
164 StgClosure *value; /* v */
165 StgClosure *finalizer;
166 struct _StgWeak *link;
169 typedef struct _StgDeadWeak { /* Weak v */
171 struct _StgWeak *link;
174 /* Byte code objects. These are fixed size objects with pointers to
175 * four arrays, designed so that a BCO can be easily "re-linked" to
176 * other BCOs, to facilitate GHC's intelligent recompilation. The
177 * array of instructions is static and not re-generated when the BCO
178 * is re-linked, but the other 3 arrays will be regenerated.
180 * A BCO represents either a function or a stack frame. In each case,
181 * it needs a bitmap to describe to the garbage collector the
182 * pointerhood of its arguments/free variables respectively, and in
183 * the case of a function it also needs an arity. These are stored
184 * directly in the BCO, rather than in the instrs array, for two
186 * (a) speed: we need to get at the bitmap info quickly when
187 * the GC is examining APs and PAPs that point to this BCO
188 * (b) a subtle interaction with the compacting GC. In compacting
189 * GC, the info that describes the size/layout of a closure
190 * cannot be in an object more than one level of indirection
191 * away from the current object, because of the order in
192 * which pointers are updated to point to their new locations.
197 StgArrWords *instrs; /* a pointer to an ArrWords */
198 StgArrWords *literals; /* a pointer to an ArrWords */
199 StgMutArrPtrs *ptrs; /* a pointer to a MutArrPtrs */
200 StgArrWords *itbls; /* a pointer to an ArrWords */
201 StgHalfWord arity; /* arity of this BCO */
202 StgHalfWord size; /* size of this BCO (in words) */
203 StgWord bitmap[FLEXIBLE_ARRAY]; /* an StgLargeBitmap */
206 #define BCO_BITMAP(bco) ((StgLargeBitmap *)((StgBCO *)(bco))->bitmap)
207 #define BCO_BITMAP_SIZE(bco) (BCO_BITMAP(bco)->size)
208 #define BCO_BITMAP_BITS(bco) (BCO_BITMAP(bco)->bitmap)
209 #define BCO_BITMAP_SIZEW(bco) ((BCO_BITMAP_SIZE(bco) + BITS_IN(StgWord) - 1) \
212 /* -----------------------------------------------------------------------------
213 Dynamic stack frames for generic heap checks.
215 These generic heap checks are slow, but have the advantage of being
216 usable in a variety of situations.
218 The one restriction is that any relevant SRTs must already be pointed
219 to from the stack. The return address doesn't need to have an info
220 table attached: hence it can be any old code pointer.
222 The liveness mask contains a 1 at bit n, if register Rn contains a
223 non-pointer. The contents of all 8 vanilla registers are always saved
224 on the stack; the liveness mask tells the GC which ones contain
227 Good places to use a generic heap check:
229 - case alternatives (the return address with an SRT is already
232 - primitives (no SRT required).
234 The stack frame layout for a RET_DYN is like this:
236 some pointers |-- RET_DYN_PTRS(liveness) words
237 some nonpointers |-- RET_DYN_NONPTRS(liveness) words
240 D1-2 |-- RET_DYN_NONPTR_REGS_SIZE words
243 R1-8 |-- RET_DYN_BITMAP_SIZE words
246 liveness mask |-- StgRetDyn structure
249 we assume that the size of a double is always 2 pointers (wasting a
250 word when it is only one pointer, but avoiding lots of #ifdefs).
252 See Liveness.h for the macros (RET_DYN_PTRS() etc.).
254 NOTE: if you change the layout of RET_DYN stack frames, then you
255 might also need to adjust the value of RESERVED_STACK_WORDS in
257 -------------------------------------------------------------------------- */
260 const struct _StgInfoTable* info;
263 StgClosure * payload[FLEXIBLE_ARRAY];
266 /* A function return stack frame: used when saving the state for a
267 * garbage collection at a function entry point. The function
268 * arguments are on the stack, and we also save the function (its
269 * info table describes the pointerhood of the arguments).
271 * The stack frame size is also cached in the frame for convenience.
274 const struct _StgInfoTable* info;
277 StgClosure * payload[FLEXIBLE_ARRAY];
280 /* Concurrent communication objects */
284 struct StgTSO_ *head;
285 struct StgTSO_ *tail;
289 /* STM data structures
291 * StgTVar defines the only type that can be updated through the STM
294 * Note that various optimisations may be possible in order to use less
295 * space for these data structures at the cost of more complexity in the
298 * - In StgTVar, current_value and first_wait_queue_entry could be held in
299 * the same field: if any thread is waiting then its expected_value for
300 * the tvar is the current value.
302 * - In StgTRecHeader, it might be worthwhile having separate chunks
303 * of read-only and read-write locations. This would save a
304 * new_value field in the read-only locations.
307 typedef struct StgTVarWaitQueue_ {
309 struct StgTSO_ *waiting_tso;
310 struct StgTVarWaitQueue_ *next_queue_entry;
311 struct StgTVarWaitQueue_ *prev_queue_entry;
316 StgClosure *current_value;
317 StgTVarWaitQueue *first_wait_queue_entry;
320 /* new_value == expected_value for read-only accesses */
321 /* new_value is a StgTVarWaitQueue entry when trec in state TREC_WAITING */
324 StgClosure *expected_value;
325 StgClosure *new_value;
328 #define TREC_CHUNK_NUM_ENTRIES 256
330 typedef struct StgTRecChunk_ {
332 struct StgTRecChunk_ *prev_chunk;
333 StgWord next_entry_idx;
334 TRecEntry entries[TREC_CHUNK_NUM_ENTRIES];
338 TREC_ACTIVE, /* Transaction in progress, outcome undecided */
339 TREC_CANNOT_COMMIT, /* Transaction in progress, inconsistent writes performed */
340 TREC_MUST_ABORT, /* Transaction in progress, inconsistent / out of date reads */
341 TREC_COMMITTED, /* Transaction has committed, now updating tvars */
342 TREC_ABORTED, /* Transaction has aborted, now reverting tvars */
343 TREC_WAITING, /* Transaction currently waiting */
346 typedef struct StgTRecHeader_ {
349 struct StgTRecHeader_ *enclosing_trec;
350 StgTRecChunk *current_chunk;
357 } StgAtomicallyFrame;
366 StgBool running_alt_code;
367 StgClosure *first_code;
368 StgClosure *alt_code;
369 StgTRecHeader *first_code_trec;
370 } StgCatchRetryFrame;
372 #if defined(PAR) || defined(GRAN)
374 StgBlockingQueueElement is a ``collective type'' representing the types
375 of closures that can be found on a blocking queue: StgTSO, StgRBHSave,
376 StgBlockedFetch. (StgRBHSave can only appear at the end of a blocking
377 queue). Logically, this is a union type, but defining another struct
378 with a common layout is easier to handle in the code.
379 Note that in the standard setup only StgTSOs can be on a blocking queue.
380 This is one of the main reasons for slightly different code in files
383 typedef struct StgBlockingQueueElement_ {
385 struct StgBlockingQueueElement_ *link; /* next elem in BQ */
386 struct StgClosure_ *payload[FLEXIBLE_ARRAY];/* contents of the closure */
387 } StgBlockingQueueElement;
389 /* only difference to std code is type of the elem in the BQ */
390 typedef struct StgBlockingQueue_ {
392 struct StgBlockingQueueElement_ *blocking_queue; /* start of the BQ */
395 /* this closure is hanging at the end of a blocking queue in (see RBH.c) */
396 typedef struct StgRBHSave_ {
398 StgClosure *payload[FLEXIBLE_ARRAY]; /* 2 words ripped out of the guts of the */
399 } StgRBHSave; /* closure holding the blocking queue */
401 typedef struct StgRBH_ {
403 struct StgBlockingQueueElement_ *blocking_queue; /* start of the BQ */
409 /* global indirections aka FETCH_ME closures */
410 typedef struct StgFetchMe_ {
412 globalAddr *ga; /* ptr to unique id for a closure */
415 /* same contents as an ordinary StgBlockingQueue */
416 typedef struct StgFetchMeBlockingQueue_ {
418 struct StgBlockingQueueElement_ *blocking_queue; /* start of the BQ */
419 } StgFetchMeBlockingQueue;
421 /* This is an entry in a blocking queue. It indicates a fetch request from a
422 TSO on another PE demanding the value of this closur. Note that a
423 StgBlockedFetch can only occur in a BQ. Once the node is evaluated and
424 updated with the result, the result will be sent back (the PE is encoded
425 in the globalAddr) and the StgBlockedFetch closure will be nuked.
427 typedef struct StgBlockedFetch_ {
429 struct StgBlockingQueueElement_ *link; /* next elem in the BQ */
430 StgClosure *node; /* node to fetch */
431 globalAddr ga; /* where to send the result to */
432 } StgBlockedFetch; /* NB: not just a ptr to a GA */
435 #endif /* CLOSURES_H */