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 StgInfoTable *saved_info;
133 StgWord payload[FLEXIBLE_ARRAY];
139 StgWord size; // ptrs plus card table
140 StgClosure *payload[FLEXIBLE_ARRAY];
141 // see also: StgMutArrPtrs macros in ClosureMacros.h
149 typedef struct _StgUpdateFrame {
156 StgInt exceptions_blocked;
167 } StgIntCharlikeClosure;
169 /* statically allocated */
174 typedef struct _StgStableName {
179 typedef struct _StgWeak { /* Weak v */
181 StgClosure *cfinalizer;
183 StgClosure *value; /* v */
184 StgClosure *finalizer;
185 struct _StgWeak *link;
188 typedef struct _StgDeadWeak { /* Weak v */
190 struct _StgWeak *link;
193 /* Byte code objects. These are fixed size objects with pointers to
194 * four arrays, designed so that a BCO can be easily "re-linked" to
195 * other BCOs, to facilitate GHC's intelligent recompilation. The
196 * array of instructions is static and not re-generated when the BCO
197 * is re-linked, but the other 3 arrays will be regenerated.
199 * A BCO represents either a function or a stack frame. In each case,
200 * it needs a bitmap to describe to the garbage collector the
201 * pointerhood of its arguments/free variables respectively, and in
202 * the case of a function it also needs an arity. These are stored
203 * directly in the BCO, rather than in the instrs array, for two
205 * (a) speed: we need to get at the bitmap info quickly when
206 * the GC is examining APs and PAPs that point to this BCO
207 * (b) a subtle interaction with the compacting GC. In compacting
208 * GC, the info that describes the size/layout of a closure
209 * cannot be in an object more than one level of indirection
210 * away from the current object, because of the order in
211 * which pointers are updated to point to their new locations.
216 StgArrWords *instrs; /* a pointer to an ArrWords */
217 StgArrWords *literals; /* a pointer to an ArrWords */
218 StgMutArrPtrs *ptrs; /* a pointer to a MutArrPtrs */
219 StgHalfWord arity; /* arity of this BCO */
220 StgHalfWord size; /* size of this BCO (in words) */
221 StgWord bitmap[FLEXIBLE_ARRAY]; /* an StgLargeBitmap */
224 #define BCO_BITMAP(bco) ((StgLargeBitmap *)((StgBCO *)(bco))->bitmap)
225 #define BCO_BITMAP_SIZE(bco) (BCO_BITMAP(bco)->size)
226 #define BCO_BITMAP_BITS(bco) (BCO_BITMAP(bco)->bitmap)
227 #define BCO_BITMAP_SIZEW(bco) ((BCO_BITMAP_SIZE(bco) + BITS_IN(StgWord) - 1) \
230 /* -----------------------------------------------------------------------------
231 Dynamic stack frames for generic heap checks.
233 These generic heap checks are slow, but have the advantage of being
234 usable in a variety of situations.
236 The one restriction is that any relevant SRTs must already be pointed
237 to from the stack. The return address doesn't need to have an info
238 table attached: hence it can be any old code pointer.
240 The liveness mask contains a 1 at bit n, if register Rn contains a
241 non-pointer. The contents of all 8 vanilla registers are always saved
242 on the stack; the liveness mask tells the GC which ones contain
245 Good places to use a generic heap check:
247 - case alternatives (the return address with an SRT is already
250 - primitives (no SRT required).
252 The stack frame layout for a RET_DYN is like this:
254 some pointers |-- RET_DYN_PTRS(liveness) words
255 some nonpointers |-- RET_DYN_NONPTRS(liveness) words
258 D1-2 |-- RET_DYN_NONPTR_REGS_SIZE words
261 R1-8 |-- RET_DYN_BITMAP_SIZE words
264 liveness mask |-- StgRetDyn structure
267 we assume that the size of a double is always 2 pointers (wasting a
268 word when it is only one pointer, but avoiding lots of #ifdefs).
270 See Liveness.h for the macros (RET_DYN_PTRS() etc.).
272 NOTE: if you change the layout of RET_DYN stack frames, then you
273 might also need to adjust the value of RESERVED_STACK_WORDS in
275 -------------------------------------------------------------------------- */
278 const StgInfoTable* info;
281 StgClosure * payload[FLEXIBLE_ARRAY];
284 /* A function return stack frame: used when saving the state for a
285 * garbage collection at a function entry point. The function
286 * arguments are on the stack, and we also save the function (its
287 * info table describes the pointerhood of the arguments).
289 * The stack frame size is also cached in the frame for convenience.
292 const StgInfoTable* info;
295 StgClosure * payload[FLEXIBLE_ARRAY];
298 /* Concurrent communication objects */
302 struct StgTSO_ *head;
303 struct StgTSO_ *tail;
308 /* STM data structures
310 * StgTVar defines the only type that can be updated through the STM
313 * Note that various optimisations may be possible in order to use less
314 * space for these data structures at the cost of more complexity in the
317 * - In StgTVar, current_value and first_watch_queue_entry could be held in
318 * the same field: if any thread is waiting then its expected_value for
319 * the tvar is the current value.
321 * - In StgTRecHeader, it might be worthwhile having separate chunks
322 * of read-only and read-write locations. This would save a
323 * new_value field in the read-only locations.
325 * - In StgAtomicallyFrame, we could combine the waiting bit into
326 * the header (maybe a different info tbl for a waiting transaction).
327 * This means we can specialise the code for the atomically frame
328 * (it immediately switches on frame->waiting anyway).
331 typedef struct StgTRecHeader_ StgTRecHeader;
333 typedef struct StgTVarWatchQueue_ {
335 StgClosure *closure; // StgTSO or StgAtomicInvariant
336 struct StgTVarWatchQueue_ *next_queue_entry;
337 struct StgTVarWatchQueue_ *prev_queue_entry;
342 StgClosure *volatile current_value;
343 StgTVarWatchQueue *volatile first_watch_queue_entry;
344 #if defined(THREADED_RTS)
345 StgInt volatile num_updates;
352 StgTRecHeader *last_execution;
354 } StgAtomicInvariant;
356 /* new_value == expected_value for read-only accesses */
357 /* new_value is a StgTVarWatchQueue entry when trec in state TREC_WAITING */
360 StgClosure *expected_value;
361 StgClosure *new_value;
362 #if defined(THREADED_RTS)
367 #define TREC_CHUNK_NUM_ENTRIES 16
369 typedef struct StgTRecChunk_ {
371 struct StgTRecChunk_ *prev_chunk;
372 StgWord next_entry_idx;
373 TRecEntry entries[TREC_CHUNK_NUM_ENTRIES];
377 TREC_ACTIVE, /* Transaction in progress, outcome undecided */
378 TREC_CONDEMNED, /* Transaction in progress, inconsistent / out of date reads */
379 TREC_COMMITTED, /* Transaction has committed, now updating tvars */
380 TREC_ABORTED, /* Transaction has aborted, now reverting tvars */
381 TREC_WAITING, /* Transaction currently waiting */
384 typedef struct StgInvariantCheckQueue_ {
386 StgAtomicInvariant *invariant;
387 StgTRecHeader *my_execution;
388 struct StgInvariantCheckQueue_ *next_queue_entry;
389 } StgInvariantCheckQueue;
391 struct StgTRecHeader_ {
394 struct StgTRecHeader_ *enclosing_trec;
395 StgTRecChunk *current_chunk;
396 StgInvariantCheckQueue *invariants_to_check;
402 StgTVarWatchQueue *next_invariant_to_check;
404 } StgAtomicallyFrame;
414 StgBool running_alt_code;
415 StgClosure *first_code;
416 StgClosure *alt_code;
417 } StgCatchRetryFrame;
419 #endif /* RTS_STORAGE_CLOSURES_H */