1 /* -----------------------------------------------------------------------------
2 * $Id: Storage.h,v 1.32 2001/05/03 16:33:27 simonmar Exp $
4 * (c) The GHC Team, 1998-1999
6 * External Storage Manger Interface
8 * ---------------------------------------------------------------------------*/
14 #include "BlockAlloc.h"
15 #include "StoragePriv.h"
17 /* -----------------------------------------------------------------------------
18 Initialisation / De-initialisation
19 -------------------------------------------------------------------------- */
21 extern void initStorage(void);
22 extern void exitStorage(void);
24 /* -----------------------------------------------------------------------------
27 StgPtr allocate(int n) Allocates a chunk of contiguous store
28 n words long, returning a pointer to
29 the first word. Always succeeds.
31 Don't forget to TICK_ALLOC_XXX(...)
32 after calling allocate, for the
33 benefit of the ticky-ticky profiler.
35 rtsBool doYouWantToGC(void) Returns True if the storage manager is
36 ready to perform a GC, False otherwise.
38 lnat allocated_bytes(void) Returns the number of bytes allocated
39 via allocate() since the last GC.
40 Used in the reoprting of statistics.
42 SMP: allocate and doYouWantToGC can be used from STG code, they are
43 surrounded by a mutex.
44 -------------------------------------------------------------------------- */
46 extern StgPtr allocate(nat n);
47 static inline rtsBool doYouWantToGC(void)
49 return (alloc_blocks >= alloc_blocks_lim);
51 extern lnat allocated_bytes(void);
53 /* -----------------------------------------------------------------------------
54 ExtendNursery(hp,hplim) When hplim is reached, try to grab
55 some more allocation space. Returns
56 False if the allocation space is
57 exhausted, and the application should
58 call GarbageCollect().
59 -------------------------------------------------------------------------- */
61 #define ExtendNursery(hp,hplim) \
62 (CurrentNursery->free = (P_)(hp)+1, \
63 CurrentNursery->link == NULL ? rtsFalse : \
64 (CurrentNursery = CurrentNursery->link, \
65 OpenNursery(hp,hplim), \
68 extern void PleaseStopAllocating(void);
70 /* -----------------------------------------------------------------------------
71 Performing Garbage Collection
73 GarbageCollect(get_roots) Performs a garbage collection.
74 'get_roots' is called to find all the
75 roots that the system knows about.
77 StgClosure Called by get_roots on each root.
78 MarkRoot(StgClosure *p) Returns the new location of the root.
79 -------------------------------------------------------------------------- */
81 extern void GarbageCollect(void (*get_roots)(void),rtsBool force_major_gc);
82 extern StgClosure *MarkRoot(StgClosure *p);
84 /* -----------------------------------------------------------------------------
85 Generational garbage collection support
87 recordMutable(StgPtr p) Informs the garbage collector that a
88 previously immutable object has
89 become (permanently) mutable. Used
90 by thawArray and similar.
92 updateWithIndirection(p1,p2) Updates the object at p1 with an
93 indirection pointing to p2. This is
94 normally called for objects in an old
95 generation (>0) when they are updated.
97 updateWithPermIndirection(p1,p2) As above but uses a permanent indir.
99 -------------------------------------------------------------------------- */
102 * Storage manager mutex
105 extern pthread_mutex_t sm_mutex;
108 /* ToDo: shouldn't recordMutable and recordOldToNewPtrs acquire some
109 * kind of lock in the SMP case?
112 recordMutable(StgMutClosure *p)
117 ASSERT(p->header.info == &stg_WHITEHOLE_info || closure_MUTABLE(p));
119 ASSERT(closure_MUTABLE(p));
123 if (bd->gen->no > 0) {
124 p->mut_link = bd->gen->mut_list;
125 bd->gen->mut_list = p;
130 recordOldToNewPtrs(StgMutClosure *p)
135 if (bd->gen->no > 0) {
136 p->mut_link = bd->gen->mut_once_list;
137 bd->gen->mut_once_list = p;
142 #define updateWithIndirection(info, p1, p2) \
146 bd = Bdescr((P_)p1); \
147 if (bd->gen->no == 0) { \
148 ((StgInd *)p1)->indirectee = p2; \
149 SET_INFO(p1,&stg_IND_info); \
150 TICK_UPD_NEW_IND(); \
152 ((StgIndOldGen *)p1)->indirectee = p2; \
153 if (info != &stg_BLACKHOLE_BQ_info) { \
154 ACQUIRE_LOCK(&sm_mutex); \
155 ((StgIndOldGen *)p1)->mut_link = bd->gen->mut_once_list; \
156 bd->gen->mut_once_list = (StgMutClosure *)p1; \
157 RELEASE_LOCK(&sm_mutex); \
159 SET_INFO(p1,&stg_IND_OLDGEN_info); \
160 TICK_UPD_OLD_IND(); \
165 /* In the DEBUG case, we also zero out the slop of the old closure,
166 * so that the sanity checker can tell where the next closure is.
168 * Two important invariants: we should never try to update a closure
169 * to point to itself, and the closure being updated should not
170 * already have been updated (the mutable list will get messed up
173 #define updateWithIndirection(info, p1, p2) \
177 ASSERT( p1 != p2 && !closure_IND(p1) ); \
178 bd = Bdescr((P_)p1); \
179 if (bd->gen->no == 0) { \
180 ((StgInd *)p1)->indirectee = p2; \
181 SET_INFO(p1,&stg_IND_info); \
182 TICK_UPD_NEW_IND(); \
184 if (info != &stg_BLACKHOLE_BQ_info) { \
186 StgInfoTable *inf = get_itbl(p1); \
187 nat np = inf->layout.payload.ptrs, \
188 nw = inf->layout.payload.nptrs, i; \
189 if (inf->type != THUNK_SELECTOR) { \
190 for (i = np; i < np + nw; i++) { \
191 ((StgClosure *)p1)->payload[i] = 0; \
195 ACQUIRE_LOCK(&sm_mutex); \
196 ((StgIndOldGen *)p1)->mut_link = bd->gen->mut_once_list; \
197 bd->gen->mut_once_list = (StgMutClosure *)p1; \
198 RELEASE_LOCK(&sm_mutex); \
200 ((StgIndOldGen *)p1)->indirectee = p2; \
201 SET_INFO(p1,&stg_IND_OLDGEN_info); \
202 TICK_UPD_OLD_IND(); \
207 /* Static objects all live in the oldest generation
209 #define updateWithStaticIndirection(info, p1, p2) \
211 ASSERT( p1 != p2 && !closure_IND(p1) ); \
212 ASSERT( ((StgMutClosure*)p1)->mut_link == NULL ); \
214 ACQUIRE_LOCK(&sm_mutex); \
215 ((StgMutClosure *)p1)->mut_link = oldest_gen->mut_once_list; \
216 oldest_gen->mut_once_list = (StgMutClosure *)p1; \
217 RELEASE_LOCK(&sm_mutex); \
219 ((StgInd *)p1)->indirectee = p2; \
220 SET_INFO((StgInd *)p1, &stg_IND_STATIC_info); \
221 TICK_UPD_STATIC_IND(); \
224 #if defined(TICKY_TICKY) || defined(PROFILING)
226 updateWithPermIndirection(const StgInfoTable *info, StgClosure *p1, StgClosure *p2)
230 ASSERT( p1 != p2 && !closure_IND(p1) );
232 if (bd->gen->no == 0) {
233 ((StgInd *)p1)->indirectee = p2;
234 SET_INFO(p1,&stg_IND_PERM_info);
235 TICK_UPD_NEW_PERM_IND(p1);
237 ((StgIndOldGen *)p1)->indirectee = p2;
238 if (info != &stg_BLACKHOLE_BQ_info) {
239 ACQUIRE_LOCK(&sm_mutex);
240 ((StgIndOldGen *)p1)->mut_link = bd->gen->mut_once_list;
241 bd->gen->mut_once_list = (StgMutClosure *)p1;
242 RELEASE_LOCK(&sm_mutex);
244 SET_INFO(p1,&stg_IND_OLDGEN_PERM_info);
245 TICK_UPD_OLD_PERM_IND();
250 /* -----------------------------------------------------------------------------
251 The CAF table - used to let us revert CAFs
252 -------------------------------------------------------------------------- */
255 void printMutOnceList(generation *gen);
256 void printMutableList(generation *gen);
259 /* --------------------------------------------------------------------------
260 Address space layout macros
261 --------------------------------------------------------------------------
263 Here are the assumptions GHC makes about address space layout.
264 Broadly, it thinks there are three sections:
266 CODE Read-only. Contains code and read-only data (such as
270 DATA Read-write data. Contains static closures (and on some
271 architectures, info tables too)
273 HEAP Dynamically-allocated closures
275 USER None of the above. The only way USER things arise right
276 now is when GHCi allocates a constructor info table, which
277 it does by mallocing them.
279 Three macros identify these three areas:
280 IS_CODE(p), IS_DATA(p), HEAP_ALLOCED(p)
282 HEAP_ALLOCED is called FOR EVERY SINGLE CLOSURE during GC.
285 Implementation of HEAP_ALLOCED
286 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
287 Concerning HEAP, most of the time (certainly under [Static] and [GHCi],
288 we ensure that the heap is allocated above some fixed address HEAP_BASE
289 (defined in MBlock.h). In this case we set TEXT_BEFORE_HEAP, and we
290 get a nice fast test.
292 Sometimes we can't be quite sure. For example in Windows, we can't
293 fix where our heap address space comes from. In this case we un-set
294 TEXT_BEFORE_HEAP. That makes it more expensive to test whether a pointer
295 comes from the HEAP section, because we need to look at the allocator's
296 address maps (see HEAP_ALLOCED macro)
298 Implementation of CODE and DATA
299 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
300 Concerning CODE and DATA, there are three main regimes:
302 [Static] Totally The segments are contiguous, and laid out
303 statically linked exactly as above
305 [GHCi] Static, GHCi may load new modules, but it knows the
306 except for GHCi address map, so for any given address it can
307 still tell which section it belongs to
309 [DLL] OS-supported Chunks of CODE and DATA may be mixed in
310 dynamic loading the address space, and we can't tell how
313 For the [Static] case, we assume memory is laid out like this
314 (in order of increasing addresses)
318 TEXT_SECTION_END_MARKER (usually _etext)
320 DATA_SECTION_END_MARKER (usually _end)
325 For the [GHCi] case, we have to consult GHCi's dynamic linker's
326 address maps, which is done by macros
327 is_dynamically_loaded_code_or_rodata_ptr
328 is_dynamically_loaded_code_or_rwdata_ptr
330 For the [DLL] case, IS_CODE and IS_DATA are really not usable at all.
334 #undef TEXT_BEFORE_HEAP
335 #ifndef mingw32_TARGET_OS
336 #define TEXT_BEFORE_HEAP 1
339 extern void* TEXT_SECTION_END_MARKER_DECL;
340 extern void* DATA_SECTION_END_MARKER_DECL;
342 /* Take into account code sections in dynamically loaded object files. */
343 #define IS_CODE_PTR(p) ( ((P_)(p) < (P_)&TEXT_SECTION_END_MARKER) \
344 || is_dynamically_loaded_code_or_rodata_ptr((char *)p) )
345 #define IS_DATA_PTR(p) ( ((P_)(p) >= (P_)&TEXT_SECTION_END_MARKER && \
346 (P_)(p) < (P_)&DATA_SECTION_END_MARKER) \
347 || is_dynamically_loaded_rwdata_ptr((char *)p) )
348 #define IS_USER_PTR(p) ( ((P_)(p) >= (P_)&DATA_SECTION_END_MARKER) \
349 && is_not_dynamically_loaded_ptr((char *)p) )
351 /* The HEAP_ALLOCED test below is called FOR EVERY SINGLE CLOSURE
352 * during GC. It needs to be FAST.
354 * BEWARE: when we're dynamically loading code (for GHCi), make sure
355 * that we don't load any code above HEAP_BASE, or this test won't work.
357 #ifdef TEXT_BEFORE_HEAP
358 # define HEAP_ALLOCED(x) ((StgPtr)(x) >= (StgPtr)(HEAP_BASE))
360 extern int is_heap_alloced(const void* x);
361 # define HEAP_ALLOCED(x) (is_heap_alloced(x))
365 /* --------------------------------------------------------------------------
366 Macros for distinguishing data pointers from code pointers
367 --------------------------------------------------------------------------
371 The garbage collector needs to make some critical distinctions between pointers.
372 In particular we need
374 LOOKS_LIKE_GHC_INFO(p) p points to an info table
376 For both of these macros, p is
377 *either* a pointer to a closure (static or heap allocated)
378 *or* a return address on the (Haskell) stack
380 (Return addresses are in fact info-pointers, so that the Haskell stack
381 looks very like a chunk of heap.)
383 The garbage collector uses LOOKS_LIKE_GHC_INFO when walking the stack, as it
384 walks over the "pending arguments" on its way to the next return address.
385 It is called moderately often, but not as often as HEAP_ALLOCED
387 ToDo: LOOKS_LIKE_GHC_INFO(p) does not return True when p points to a
388 constructor info table allocated by GHCi. We should really rename
389 LOOKS_LIKE_GHC_INFO to LOOKS_LIKE_GHC_RETURN_INFO.
393 LOOKS_LIKE_GHC_INFO is more complicated because of the need to distinguish
394 between static closures and info tables. It's a known portability problem.
395 We have three approaches:
397 Plan A: Address-space partitioning.
398 Keep info tables in the (single, contiguous) text segment: IS_CODE_PTR(p)
399 and static closures in the (single, contiguous) data segment: IS_DATA_PTR(p)
401 Plan A can fail for two reasons:
402 * In many environments (eg. dynamic loading),
403 text and data aren't in a single contiguous range.
404 * When we compile through vanilla C (no mangling) we sometimes
405 can't guaranteee to put info tables in the text section. This
406 happens eg. on MacOS where the C compiler refuses to put const
407 data in the text section if it has any code pointers in it
408 (which info tables do *only* when we're compiling without
409 TABLES_NEXT_TO_CODE).
411 Hence, Plan B: (compile-via-C-with-mangling, or native code generation)
412 Put a zero word before each static closure.
413 When compiling to native code, or via C-with-mangling, info tables
414 are laid out "backwards" from the address specified in the info pointer
415 (the entry code goes forward from the info pointer). Hence, the word
416 before the one referenced the info pointer is part of the info table,
417 and is guaranteed non-zero.
419 For reasons nobody seems to fully understand, the statically-allocated tables
420 of INTLIKE and CHARLIKE closures can't have this zero word, so we
421 have to test separately for them.
423 Plan B fails altogether for the compile-through-vanilla-C route, because
424 info tables aren't laid out backwards.
427 Hence, Plan C: (unregisterised, compile-through-vanilla-C route only)
428 If we didn't manage to get info tables into the text section, then
429 we can distinguish between a static closure pointer and an info
430 pointer as follows: the first word of an info table is a code pointer,
431 and therefore in text space, whereas the first word of a closure pointer
432 is an info pointer, and therefore not. Shazam!
436 /* When working with Win32 DLLs, static closures are identified by
437 being prefixed with a zero word. This is needed so that we can
438 distinguish between pointers to static closures and (reversed!)
441 This 'scheme' breaks down for closure tables such as CHARLIKE,
442 so we catch these separately.
444 LOOKS_LIKE_STATIC_CLOSURE()
445 - discriminates between static closures and info tbls
446 (needed by LOOKS_LIKE_GHC_INFO() below - [Win32 DLLs only.])
448 - distinguishes between static and heap allocated data.
450 #if defined(ENABLE_WIN32_DLL_SUPPORT)
451 /* definitely do not enable for mingw DietHEP */
452 #define LOOKS_LIKE_STATIC(r) (!(HEAP_ALLOCED(r)))
454 /* Tiresome predicates needed to check for pointers into the closure tables */
455 #define IS_CHARLIKE_CLOSURE(p) \
456 ( (P_)(p) >= (P_)stg_CHARLIKE_closure && \
457 (char*)(p) <= ((char*)stg_CHARLIKE_closure + \
458 (MAX_CHARLIKE-MIN_CHARLIKE) * sizeof(StgIntCharlikeClosure)) )
459 #define IS_INTLIKE_CLOSURE(p) \
460 ( (P_)(p) >= (P_)stg_INTLIKE_closure && \
461 (char*)(p) <= ((char*)stg_INTLIKE_closure + \
462 (MAX_INTLIKE-MIN_INTLIKE) * sizeof(StgIntCharlikeClosure)) )
464 #define LOOKS_LIKE_STATIC_CLOSURE(r) (((*(((unsigned long *)(r))-1)) == 0) || IS_CHARLIKE_CLOSURE(r) || IS_INTLIKE_CLOSURE(r))
466 #define LOOKS_LIKE_STATIC(r) IS_DATA_PTR(r)
467 #define LOOKS_LIKE_STATIC_CLOSURE(r) IS_DATA_PTR(r)
471 /* -----------------------------------------------------------------------------
472 Macros for distinguishing infotables from closures.
474 You'd think it'd be easy to tell an info pointer from a closure pointer:
475 closures live on the heap and infotables are in read only memory. Right?
476 Wrong! Static closures live in read only memory and Hugs allocates
477 infotables for constructors on the (writable) C heap.
478 -------------------------------------------------------------------------- */
480 /* not accurate by any means, but stops the assertions failing... */
481 /* TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO */
482 #define IS_HUGS_CONSTR_INFO(info) IS_USER_PTR(info)
484 /* LOOKS_LIKE_GHC_INFO is called moderately often during GC, but
485 * Certainly not as often as HEAP_ALLOCED.
487 #ifdef TEXT_BEFORE_HEAP /* needed for mingw DietHEP */
488 # define LOOKS_LIKE_GHC_INFO(info) IS_CODE_PTR(info)
490 # define LOOKS_LIKE_GHC_INFO(info) (!HEAP_ALLOCED(info) \
491 && !LOOKS_LIKE_STATIC_CLOSURE(info))
495 /* -----------------------------------------------------------------------------
496 Macros for calculating how big a closure will be (used during allocation)
497 -------------------------------------------------------------------------- */
499 /* ToDo: replace unsigned int by nat. The only fly in the ointment is that
500 * nat comes from Rts.h which many folk dont include. Sigh!
502 static __inline__ StgOffset AP_sizeW ( unsigned int n_args )
503 { return sizeofW(StgAP_UPD) + n_args; }
505 static __inline__ StgOffset PAP_sizeW ( unsigned int n_args )
506 { return sizeofW(StgPAP) + n_args; }
508 static __inline__ StgOffset CONSTR_sizeW( unsigned int p, unsigned int np )
509 { return sizeofW(StgHeader) + p + np; }
511 static __inline__ StgOffset THUNK_SELECTOR_sizeW ( void )
512 { return sizeofW(StgHeader) + MIN_UPD_SIZE; }
514 static __inline__ StgOffset BLACKHOLE_sizeW ( void )
515 { return sizeofW(StgHeader) + MIN_UPD_SIZE; }
517 /* --------------------------------------------------------------------------
519 * ------------------------------------------------------------------------*/
521 static __inline__ StgOffset sizeW_fromITBL( const StgInfoTable* itbl )
522 { return sizeofW(StgClosure)
523 + sizeofW(StgPtr) * itbl->layout.payload.ptrs
524 + sizeofW(StgWord) * itbl->layout.payload.nptrs; }
526 static __inline__ StgOffset pap_sizeW( StgPAP* x )
527 { return PAP_sizeW(x->n_args); }
529 static __inline__ StgOffset arr_words_sizeW( StgArrWords* x )
530 { return sizeofW(StgArrWords) + x->words; }
532 static __inline__ StgOffset mut_arr_ptrs_sizeW( StgMutArrPtrs* x )
533 { return sizeofW(StgMutArrPtrs) + x->ptrs; }
535 static __inline__ StgWord tso_sizeW ( StgTSO *tso )
536 { return TSO_STRUCT_SIZEW + tso->stack_size; }
538 #endif /* STORAGE_H */