1 /* -----------------------------------------------------------------------------
2 * $Id: Storage.h,v 1.40 2002/02/04 20:21:16 sof Exp $
4 * (c) The GHC Team, 1998-1999
6 * External Storage Manger Interface
8 * ---------------------------------------------------------------------------*/
15 #include "BlockAlloc.h"
16 #include "StoragePriv.h"
18 #include "LdvProfile.h"
21 /* -----------------------------------------------------------------------------
22 Initialisation / De-initialisation
23 -------------------------------------------------------------------------- */
25 extern void initStorage(void);
26 extern void exitStorage(void);
28 /* -----------------------------------------------------------------------------
31 StgPtr allocate(nat n) Allocates a chunk of contiguous store
32 n words long, returning a pointer to
33 the first word. Always succeeds.
35 StgPtr allocatePinned(nat n) Allocates a chunk of contiguous store
36 n words long, which is at a fixed
37 address (won't be moved by GC).
38 Returns a pointer to the first word.
41 NOTE: the GC can't in general handle
42 pinned objects, so allocatePinned()
43 can only be used for ByteArrays at the
46 Don't forget to TICK_ALLOC_XXX(...)
47 after calling allocate or
48 allocatePinned, for the
49 benefit of the ticky-ticky profiler.
51 rtsBool doYouWantToGC(void) Returns True if the storage manager is
52 ready to perform a GC, False otherwise.
54 lnat allocated_bytes(void) Returns the number of bytes allocated
55 via allocate() since the last GC.
56 Used in the reoprting of statistics.
58 SMP: allocate and doYouWantToGC can be used from STG code, they are
59 surrounded by a mutex.
60 -------------------------------------------------------------------------- */
62 extern StgPtr allocate ( nat n );
63 extern StgPtr allocatePinned ( nat n );
64 extern lnat allocated_bytes ( void );
69 return (alloc_blocks >= alloc_blocks_lim);
72 /* -----------------------------------------------------------------------------
73 ExtendNursery(hp,hplim) When hplim is reached, try to grab
74 some more allocation space. Returns
75 False if the allocation space is
76 exhausted, and the application should
77 call GarbageCollect().
78 -------------------------------------------------------------------------- */
80 #define ExtendNursery(hp,hplim) \
81 (CurrentNursery->free = (P_)(hp)+1, \
82 CurrentNursery->link == NULL ? rtsFalse : \
83 (CurrentNursery = CurrentNursery->link, \
84 OpenNursery(hp,hplim), \
87 extern void PleaseStopAllocating(void);
89 /* -----------------------------------------------------------------------------
90 Performing Garbage Collection
92 GarbageCollect(get_roots) Performs a garbage collection.
93 'get_roots' is called to find all the
94 roots that the system knows about.
96 StgClosure Called by get_roots on each root.
97 MarkRoot(StgClosure *p) Returns the new location of the root.
98 -------------------------------------------------------------------------- */
100 extern void GarbageCollect(void (*get_roots)(evac_fn),rtsBool force_major_gc);
102 /* -----------------------------------------------------------------------------
103 Generational garbage collection support
105 recordMutable(StgPtr p) Informs the garbage collector that a
106 previously immutable object has
107 become (permanently) mutable. Used
108 by thawArray and similar.
110 updateWithIndirection(p1,p2) Updates the object at p1 with an
111 indirection pointing to p2. This is
112 normally called for objects in an old
113 generation (>0) when they are updated.
115 updateWithPermIndirection(p1,p2) As above but uses a permanent indir.
117 -------------------------------------------------------------------------- */
120 * Storage manager mutex
123 extern Mutex sm_mutex;
124 #define ACQUIRE_SM_LOCK ACQUIRE_LOCK(&sm_mutex)
125 #define RELEASE_SM_LOCK RELEASE_LOCK(&sm_mutex)
127 #define ACQUIRE_SM_LOCK
128 #define RELEASE_SM_LOCK
131 /* ToDo: shouldn't recordMutable and recordOldToNewPtrs acquire some
132 * kind of lock in the SMP case?
135 recordMutable(StgMutClosure *p)
140 ASSERT(p->header.info == &stg_WHITEHOLE_info || closure_MUTABLE(p));
142 ASSERT(closure_MUTABLE(p));
146 if (bd->gen_no > 0) {
147 p->mut_link = generations[bd->gen_no].mut_list;
148 generations[bd->gen_no].mut_list = p;
153 recordOldToNewPtrs(StgMutClosure *p)
158 if (bd->gen_no > 0) {
159 p->mut_link = generations[bd->gen_no].mut_once_list;
160 generations[bd->gen_no].mut_once_list = p;
165 // We zero out the slop when PROFILING is on.
167 #if !defined(DEBUG) && !defined(PROFILING)
168 #define updateWithIndirection(info, p1, p2) \
172 bd = Bdescr((P_)p1); \
173 if (bd->gen_no == 0) { \
174 ((StgInd *)p1)->indirectee = p2; \
175 SET_INFO(p1,&stg_IND_info); \
176 TICK_UPD_NEW_IND(); \
178 ((StgIndOldGen *)p1)->indirectee = p2; \
179 if (info != &stg_BLACKHOLE_BQ_info) { \
181 ((StgIndOldGen *)p1)->mut_link = generations[bd->gen_no].mut_once_list; \
182 generations[bd->gen_no].mut_once_list = (StgMutClosure *)p1; \
185 SET_INFO(p1,&stg_IND_OLDGEN_info); \
186 TICK_UPD_OLD_IND(); \
189 #elif defined(PROFILING)
191 // We call LDV_recordDead_FILL_SLOP_DYNAMIC(p1) regardless of the generation in
195 // After all, we do *NOT* need to call LDV_recordCreate() for both IND and
196 // IND_OLDGEN closures because they are inherently used. But, it corrupts
197 // the invariants that every closure keeps its creation time in the profiling
198 // field. So, we call LDV_recordCreate().
200 #define updateWithIndirection(info, p1, p2) \
204 LDV_recordDead_FILL_SLOP_DYNAMIC((p1)); \
205 bd = Bdescr((P_)p1); \
206 if (bd->gen_no == 0) { \
207 ((StgInd *)p1)->indirectee = p2; \
208 SET_INFO(p1,&stg_IND_info); \
209 LDV_recordCreate((p1)); \
210 TICK_UPD_NEW_IND(); \
212 ((StgIndOldGen *)p1)->indirectee = p2; \
213 if (info != &stg_BLACKHOLE_BQ_info) { \
215 ((StgIndOldGen *)p1)->mut_link = generations[bd->gen_no].mut_once_list; \
216 generations[bd->gen_no].mut_once_list = (StgMutClosure *)p1; \
219 SET_INFO(p1,&stg_IND_OLDGEN_info); \
220 LDV_recordCreate((p1)); \
226 /* In the DEBUG case, we also zero out the slop of the old closure,
227 * so that the sanity checker can tell where the next closure is.
229 * Two important invariants: we should never try to update a closure
230 * to point to itself, and the closure being updated should not
231 * already have been updated (the mutable list will get messed up
234 #define updateWithIndirection(info, p1, p2) \
238 ASSERT( p1 != p2 && !closure_IND(p1) ); \
239 bd = Bdescr((P_)p1); \
240 if (bd->gen_no == 0) { \
241 ((StgInd *)p1)->indirectee = p2; \
242 SET_INFO(p1,&stg_IND_info); \
243 TICK_UPD_NEW_IND(); \
245 if (info != &stg_BLACKHOLE_BQ_info) { \
247 StgInfoTable *inf = get_itbl(p1); \
248 nat np = inf->layout.payload.ptrs, \
249 nw = inf->layout.payload.nptrs, i; \
250 if (inf->type != THUNK_SELECTOR) { \
251 for (i = np; i < np + nw; i++) { \
252 ((StgClosure *)p1)->payload[i] = 0; \
257 ((StgIndOldGen *)p1)->mut_link = generations[bd->gen_no].mut_once_list; \
258 generations[bd->gen_no].mut_once_list = (StgMutClosure *)p1; \
261 ((StgIndOldGen *)p1)->indirectee = p2; \
262 SET_INFO(p1,&stg_IND_OLDGEN_info); \
263 TICK_UPD_OLD_IND(); \
268 /* Static objects all live in the oldest generation
270 #define updateWithStaticIndirection(info, p1, p2) \
272 ASSERT( p1 != p2 && !closure_IND(p1) ); \
273 ASSERT( ((StgMutClosure*)p1)->mut_link == NULL ); \
276 ((StgMutClosure *)p1)->mut_link = oldest_gen->mut_once_list; \
277 oldest_gen->mut_once_list = (StgMutClosure *)p1; \
280 ((StgInd *)p1)->indirectee = p2; \
281 SET_INFO((StgInd *)p1, &stg_IND_STATIC_info); \
282 TICK_UPD_STATIC_IND(); \
285 #if defined(TICKY_TICKY) || defined(PROFILING)
287 updateWithPermIndirection(const StgInfoTable *info, StgClosure *p1, StgClosure *p2)
291 ASSERT( p1 != p2 && !closure_IND(p1) );
295 // Destroy the old closure.
296 // Nb: LDV_* stuff cannot mix with ticky-ticky
297 LDV_recordDead_FILL_SLOP_DYNAMIC(p1);
300 if (bd->gen_no == 0) {
301 ((StgInd *)p1)->indirectee = p2;
302 SET_INFO(p1,&stg_IND_PERM_info);
305 // We have just created a new closure.
306 LDV_recordCreate(p1);
308 TICK_UPD_NEW_PERM_IND(p1);
310 ((StgIndOldGen *)p1)->indirectee = p2;
311 if (info != &stg_BLACKHOLE_BQ_info) {
313 ((StgIndOldGen *)p1)->mut_link = generations[bd->gen_no].mut_once_list;
314 generations[bd->gen_no].mut_once_list = (StgMutClosure *)p1;
317 SET_INFO(p1,&stg_IND_OLDGEN_PERM_info);
320 // We have just created a new closure.
321 LDV_recordCreate(p1);
323 TICK_UPD_OLD_PERM_IND();
328 /* -----------------------------------------------------------------------------
329 The CAF table - used to let us revert CAFs
330 -------------------------------------------------------------------------- */
332 void revertCAFs( void );
335 void printMutOnceList(generation *gen);
336 void printMutableList(generation *gen);
339 /* --------------------------------------------------------------------------
340 Address space layout macros
341 --------------------------------------------------------------------------
343 Here are the assumptions GHC makes about address space layout.
344 Broadly, it thinks there are three sections:
346 CODE Read-only. Contains code and read-only data (such as
350 DATA Read-write data. Contains static closures (and on some
351 architectures, info tables too)
353 HEAP Dynamically-allocated closures
355 USER None of the above. The only way USER things arise right
356 now is when GHCi allocates a constructor info table, which
357 it does by mallocing them.
359 Three macros identify these three areas:
360 IS_DATA(p), HEAP_ALLOCED(p)
362 HEAP_ALLOCED is called FOR EVERY SINGLE CLOSURE during GC.
365 Implementation of HEAP_ALLOCED
366 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
367 Concerning HEAP, most of the time (certainly under [Static] and [GHCi],
368 we ensure that the heap is allocated above some fixed address HEAP_BASE
369 (defined in MBlock.h). In this case we set TEXT_BEFORE_HEAP, and we
370 get a nice fast test.
372 Sometimes we can't be quite sure. For example in Windows, we can't
373 fix where our heap address space comes from. In this case we un-set
374 TEXT_BEFORE_HEAP. That makes it more expensive to test whether a pointer
375 comes from the HEAP section, because we need to look at the allocator's
376 address maps (see HEAP_ALLOCED macro)
378 Implementation of CODE and DATA
379 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
380 Concerning CODE and DATA, there are three main regimes:
382 [Static] Totally The segments are contiguous, and laid out
383 statically linked exactly as above
385 [GHCi] Static, GHCi may load new modules, but it knows the
386 except for GHCi address map, so for any given address it can
387 still tell which section it belongs to
389 [DLL] OS-supported Chunks of CODE and DATA may be mixed in
390 dynamic loading the address space, and we can't tell how
393 For the [Static] case, we assume memory is laid out like this
394 (in order of increasing addresses)
398 TEXT_SECTION_END_MARKER (usually _etext)
400 DATA_SECTION_END_MARKER (usually _end)
405 For the [GHCi] case, we have to consult GHCi's dynamic linker's
406 address maps, which is done by macros
407 is_dynamically_loaded_code_or_rodata_ptr
408 is_dynamically_loaded_code_or_rwdata_ptr
410 For the [DLL] case, IS_DATA is really not usable at all.
414 #undef TEXT_BEFORE_HEAP
415 #ifndef mingw32_TARGET_OS
416 #define TEXT_BEFORE_HEAP 1
419 extern void* TEXT_SECTION_END_MARKER_DECL;
420 extern void* DATA_SECTION_END_MARKER_DECL;
422 /* Take into account code sections in dynamically loaded object files. */
423 #define IS_DATA_PTR(p) ( ((P_)(p) >= (P_)&TEXT_SECTION_END_MARKER && \
424 (P_)(p) < (P_)&DATA_SECTION_END_MARKER) \
425 || is_dynamically_loaded_rwdata_ptr((char *)p) )
426 #define IS_USER_PTR(p) ( ((P_)(p) >= (P_)&DATA_SECTION_END_MARKER) \
427 && is_not_dynamically_loaded_ptr((char *)p) )
429 /* The HEAP_ALLOCED test below is called FOR EVERY SINGLE CLOSURE
430 * during GC. It needs to be FAST.
432 * BEWARE: when we're dynamically loading code (for GHCi), make sure
433 * that we don't load any code above HEAP_BASE, or this test won't work.
435 #ifdef TEXT_BEFORE_HEAP
436 # define HEAP_ALLOCED(x) ((StgPtr)(x) >= (StgPtr)(HEAP_BASE))
438 extern int is_heap_alloced(const void* x);
439 # define HEAP_ALLOCED(x) (is_heap_alloced(x))
443 /* --------------------------------------------------------------------------
444 Macros for distinguishing data pointers from code pointers
445 --------------------------------------------------------------------------
449 The garbage collector needs to make some critical distinctions between pointers.
450 In particular we need
452 LOOKS_LIKE_GHC_INFO(p) p points to an info table
454 For both of these macros, p is
455 *either* a pointer to a closure (static or heap allocated)
456 *or* a return address on the (Haskell) stack
458 (Return addresses are in fact info-pointers, so that the Haskell stack
459 looks very like a chunk of heap.)
461 The garbage collector uses LOOKS_LIKE_GHC_INFO when walking the stack, as it
462 walks over the "pending arguments" on its way to the next return address.
463 It is called moderately often, but not as often as HEAP_ALLOCED
465 ToDo: LOOKS_LIKE_GHC_INFO(p) does not return True when p points to a
466 constructor info table allocated by GHCi. We should really rename
467 LOOKS_LIKE_GHC_INFO to LOOKS_LIKE_GHC_RETURN_INFO.
471 LOOKS_LIKE_GHC_INFO is more complicated because of the need to distinguish
472 between static closures and info tables. It's a known portability problem.
473 We have three approaches:
475 Plan A: Address-space partitioning.
476 keep static closures in the (single, contiguous) data segment: IS_DATA_PTR(p)
478 Plan A can fail for two reasons:
479 * In many environments (eg. dynamic loading),
480 text and data aren't in a single contiguous range.
481 * When we compile through vanilla C (no mangling) we sometimes
482 can't guaranteee to put info tables in the text section. This
483 happens eg. on MacOS where the C compiler refuses to put const
484 data in the text section if it has any code pointers in it
485 (which info tables do *only* when we're compiling without
486 TABLES_NEXT_TO_CODE).
488 Hence, Plan B: (compile-via-C-with-mangling, or native code generation)
489 Put a zero word before each static closure.
490 When compiling to native code, or via C-with-mangling, info tables
491 are laid out "backwards" from the address specified in the info pointer
492 (the entry code goes forward from the info pointer). Hence, the word
493 before the one referenced the info pointer is part of the info table,
494 and is guaranteed non-zero.
496 For reasons nobody seems to fully understand, the statically-allocated tables
497 of INTLIKE and CHARLIKE closures can't have this zero word, so we
498 have to test separately for them.
500 Plan B fails altogether for the compile-through-vanilla-C route, because
501 info tables aren't laid out backwards.
504 Hence, Plan C: (unregisterised, compile-through-vanilla-C route only)
505 If we didn't manage to get info tables into the text section, then
506 we can distinguish between a static closure pointer and an info
507 pointer as follows: the first word of an info table is a code pointer,
508 and therefore in text space, whereas the first word of a closure pointer
509 is an info pointer, and therefore not. Shazam!
513 /* When working with Win32 DLLs, static closures are identified by
514 being prefixed with a zero word. This is needed so that we can
515 distinguish between pointers to static closures and (reversed!)
518 This 'scheme' breaks down for closure tables such as CHARLIKE,
519 so we catch these separately.
521 LOOKS_LIKE_STATIC_CLOSURE()
522 - discriminates between static closures and info tbls
523 (needed by LOOKS_LIKE_GHC_INFO() below - [Win32 DLLs only.])
525 - distinguishes between static and heap allocated data.
527 #if defined(ENABLE_WIN32_DLL_SUPPORT)
528 /* definitely do not enable for mingw DietHEP */
529 #define LOOKS_LIKE_STATIC(r) (!(HEAP_ALLOCED(r)))
531 /* Tiresome predicates needed to check for pointers into the closure tables */
532 #define IS_CHARLIKE_CLOSURE(p) \
533 ( (P_)(p) >= (P_)stg_CHARLIKE_closure && \
534 (char*)(p) <= ((char*)stg_CHARLIKE_closure + \
535 (MAX_CHARLIKE-MIN_CHARLIKE) * sizeof(StgIntCharlikeClosure)) )
536 #define IS_INTLIKE_CLOSURE(p) \
537 ( (P_)(p) >= (P_)stg_INTLIKE_closure && \
538 (char*)(p) <= ((char*)stg_INTLIKE_closure + \
539 (MAX_INTLIKE-MIN_INTLIKE) * sizeof(StgIntCharlikeClosure)) )
541 #define LOOKS_LIKE_STATIC_CLOSURE(r) (((*(((unsigned long *)(r))-1)) == 0) || IS_CHARLIKE_CLOSURE(r) || IS_INTLIKE_CLOSURE(r))
543 #define LOOKS_LIKE_STATIC(r) IS_DATA_PTR(r)
544 #define LOOKS_LIKE_STATIC_CLOSURE(r) IS_DATA_PTR(r)
548 /* -----------------------------------------------------------------------------
549 Macros for distinguishing infotables from closures.
551 You'd think it'd be easy to tell an info pointer from a closure pointer:
552 closures live on the heap and infotables are in read only memory. Right?
553 Wrong! Static closures live in read only memory and Hugs allocates
554 infotables for constructors on the (writable) C heap.
555 -------------------------------------------------------------------------- */
557 /* not accurate by any means, but stops the assertions failing... */
558 /* TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO */
559 #define IS_HUGS_CONSTR_INFO(info) IS_USER_PTR(info)
561 /* LOOKS_LIKE_GHC_INFO is called moderately often during GC, but
562 * Certainly not as often as HEAP_ALLOCED.
564 #define LOOKS_LIKE_GHC_INFO(info) (!HEAP_ALLOCED(info) \
565 && !LOOKS_LIKE_STATIC_CLOSURE(info))
567 /* -----------------------------------------------------------------------------
568 Macros for calculating how big a closure will be (used during allocation)
569 -------------------------------------------------------------------------- */
571 static __inline__ StgOffset AP_sizeW ( nat n_args )
572 { return sizeofW(StgAP_UPD) + n_args; }
574 static __inline__ StgOffset PAP_sizeW ( nat n_args )
575 { return sizeofW(StgPAP) + n_args; }
577 static __inline__ StgOffset CONSTR_sizeW( nat p, nat np )
578 { return sizeofW(StgHeader) + p + np; }
580 static __inline__ StgOffset THUNK_SELECTOR_sizeW ( void )
581 { return sizeofW(StgHeader) + MIN_UPD_SIZE; }
583 static __inline__ StgOffset BLACKHOLE_sizeW ( void )
584 { return sizeofW(StgHeader) + MIN_UPD_SIZE; }
586 /* --------------------------------------------------------------------------
588 * ------------------------------------------------------------------------*/
590 static __inline__ StgOffset sizeW_fromITBL( const StgInfoTable* itbl )
591 { return sizeofW(StgClosure)
592 + sizeofW(StgPtr) * itbl->layout.payload.ptrs
593 + sizeofW(StgWord) * itbl->layout.payload.nptrs; }
595 static __inline__ StgOffset pap_sizeW( StgPAP* x )
596 { return PAP_sizeW(x->n_args); }
598 static __inline__ StgOffset arr_words_sizeW( StgArrWords* x )
599 { return sizeofW(StgArrWords) + x->words; }
601 static __inline__ StgOffset mut_arr_ptrs_sizeW( StgMutArrPtrs* x )
602 { return sizeofW(StgMutArrPtrs) + x->ptrs; }
604 static __inline__ StgWord tso_sizeW ( StgTSO *tso )
605 { return TSO_STRUCT_SIZEW + tso->stack_size; }
607 #endif /* STORAGE_H */