1 /* -----------------------------------------------------------------------------
2 * $Id: Storage.h,v 1.29 2001/02/11 17:51:08 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 #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 if (info != &stg_BLACKHOLE_BQ_info) { \
180 StgInfoTable *inf = get_itbl(p1); \
181 nat np = inf->layout.payload.ptrs, \
182 nw = inf->layout.payload.nptrs, i; \
183 if (inf->type != THUNK_SELECTOR) { \
184 for (i = np; i < np + nw; i++) { \
185 ((StgClosure *)p1)->payload[i] = 0; \
189 ACQUIRE_LOCK(&sm_mutex); \
190 ((StgIndOldGen *)p1)->mut_link = bd->gen->mut_once_list; \
191 bd->gen->mut_once_list = (StgMutClosure *)p1; \
192 RELEASE_LOCK(&sm_mutex); \
194 ((StgIndOldGen *)p1)->indirectee = p2; \
195 SET_INFO(p1,&stg_IND_OLDGEN_info); \
196 TICK_UPD_OLD_IND(); \
201 /* Static objects all live in the oldest generation
203 #define updateWithStaticIndirection(info, p1, p2) \
205 ASSERT( ((StgMutClosure*)p1)->mut_link == NULL ); \
207 ACQUIRE_LOCK(&sm_mutex); \
208 ((StgMutClosure *)p1)->mut_link = oldest_gen->mut_once_list; \
209 oldest_gen->mut_once_list = (StgMutClosure *)p1; \
210 RELEASE_LOCK(&sm_mutex); \
212 ((StgInd *)p1)->indirectee = p2; \
213 SET_INFO((StgInd *)p1, &stg_IND_STATIC_info); \
214 TICK_UPD_STATIC_IND(); \
217 #if defined(TICKY_TICKY) || defined(PROFILING)
219 updateWithPermIndirection(const StgInfoTable *info, StgClosure *p1, StgClosure *p2)
224 if (bd->gen->no == 0) {
225 ((StgInd *)p1)->indirectee = p2;
226 SET_INFO(p1,&stg_IND_PERM_info);
227 TICK_UPD_NEW_PERM_IND(p1);
229 ((StgIndOldGen *)p1)->indirectee = p2;
230 if (info != &stg_BLACKHOLE_BQ_info) {
231 ACQUIRE_LOCK(&sm_mutex);
232 ((StgIndOldGen *)p1)->mut_link = bd->gen->mut_once_list;
233 bd->gen->mut_once_list = (StgMutClosure *)p1;
234 RELEASE_LOCK(&sm_mutex);
236 SET_INFO(p1,&stg_IND_OLDGEN_PERM_info);
237 TICK_UPD_OLD_PERM_IND();
242 /* -----------------------------------------------------------------------------
243 The CAF table - used to let us revert CAFs
244 -------------------------------------------------------------------------- */
247 void printMutOnceList(generation *gen);
248 void printMutableList(generation *gen);
251 /* --------------------------------------------------------------------------
252 Address space layout macros
253 --------------------------------------------------------------------------
255 Here are the assumptions GHC makes about address space layout.
256 Broadly, it thinks there are three sections:
258 CODE Read-only. Contains code and read-only data (such as
262 DATA Read-write data. Contains static closures (and on some
263 architectures, info tables too)
265 HEAP Dynamically-allocated closures
267 USER None of the above. The only way USER things arise right
268 now is when GHCi allocates a constructor info table, which
269 it does by mallocing them.
271 Three macros identify these three areas:
272 IS_CODE(p), IS_DATA(p), HEAP_ALLOCED(p)
274 HEAP_ALLOCED is called FOR EVERY SINGLE CLOSURE during GC.
277 Implementation of HEAP_ALLOCED
278 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
279 Concerning HEAP, most of the time (certainly under [Static] and [GHCi],
280 we ensure that the heap is allocated above some fixed address HEAP_BASE
281 (defined in MBlock.h). In this case we set TEXT_BEFORE_HEAP, and we
282 get a nice fast test.
284 Sometimes we can't be quite sure. For example in Windows, we can't
285 fix where our heap address space comes from. In this case we un-set
286 TEXT_BEFORE_HEAP. That makes it more expensive to test whether a pointer
287 comes from the HEAP section, because we need to look at the allocator's
288 address maps (see HEAP_ALLOCED macro)
290 Implementation of CODE and DATA
291 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
292 Concerning CODE and DATA, there are three main regimes:
294 [Static] Totally The segments are contiguous, and laid out
295 statically linked exactly as above
297 [GHCi] Static, GHCi may load new modules, but it knows the
298 except for GHCi address map, so for any given address it can
299 still tell which section it belongs to
301 [DLL] OS-supported Chunks of CODE and DATA may be mixed in
302 dynamic loading the address space, and we can't tell how
305 For the [Static] case, we assume memory is laid out like this
306 (in order of increasing addresses)
310 TEXT_SECTION_END_MARKER (usually _etext)
312 DATA_SECTION_END_MARKER (usually _end)
317 For the [GHCi] case, we have to consult GHCi's dynamic linker's
318 address maps, which is done by macros
319 is_dynamically_loaded_code_or_rodata_ptr
320 is_dynamically_loaded_code_or_rwdata_ptr
322 For the [DLL] case, IS_CODE and IS_DATA are really not usable at all.
326 #undef TEXT_BEFORE_HEAP
327 #ifndef mingw32_TARGET_OS
328 #define TEXT_BEFORE_HEAP 1
331 extern void* TEXT_SECTION_END_MARKER_DECL;
332 extern void* DATA_SECTION_END_MARKER_DECL;
334 /* Take into account code sections in dynamically loaded object files. */
335 #define IS_CODE_PTR(p) ( ((P_)(p) < (P_)&TEXT_SECTION_END_MARKER) \
336 || is_dynamically_loaded_code_or_rodata_ptr((char *)p) )
337 #define IS_DATA_PTR(p) ( ((P_)(p) >= (P_)&TEXT_SECTION_END_MARKER && \
338 (P_)(p) < (P_)&DATA_SECTION_END_MARKER) \
339 || is_dynamically_loaded_rwdata_ptr((char *)p) )
340 #define IS_USER_PTR(p) ( ((P_)(p) >= (P_)&DATA_SECTION_END_MARKER) \
341 && is_not_dynamically_loaded_ptr((char *)p) )
343 /* The HEAP_ALLOCED test below is called FOR EVERY SINGLE CLOSURE
344 * during GC. It needs to be FAST.
346 * BEWARE: when we're dynamically loading code (for GHCi), make sure
347 * that we don't load any code above HEAP_BASE, or this test won't work.
349 #ifdef TEXT_BEFORE_HEAP
350 # define HEAP_ALLOCED(x) ((StgPtr)(x) >= (StgPtr)(HEAP_BASE))
352 extern int is_heap_alloced(const void* x);
353 # define HEAP_ALLOCED(x) (is_heap_alloced(x))
357 /* --------------------------------------------------------------------------
358 Macros for distinguishing data pointers from code pointers
359 --------------------------------------------------------------------------
363 The garbage collector needs to make some critical distinctions between pointers.
364 In particular we need
366 LOOKS_LIKE_GHC_INFO(p) p points to an info table
368 For both of these macros, p is
369 *either* a pointer to a closure (static or heap allocated)
370 *or* a return address on the (Haskell) stack
372 (Return addresses are in fact info-pointers, so that the Haskell stack
373 looks very like a chunk of heap.)
375 The garbage collector uses LOOKS_LIKE_GHC_INFO when walking the stack, as it
376 walks over the "pending arguments" on its way to the next return address.
377 It is called moderately often, but not as often as HEAP_ALLOCED
379 ToDo: LOOKS_LIKE_GHC_INFO(p) does not return True when p points to a
380 constructor info table allocated by GHCi. We should really rename
381 LOOKS_LIKE_GHC_INFO to LOOKS_LIKE_GHC_RETURN_INFO.
385 LOOKS_LIKE_GHC_INFO is more complicated because of the need to distinguish
386 between static closures and info tables. It's a known portability problem.
387 We have three approaches:
389 Plan A: Address-space partitioning.
390 Keep info tables in the (single, contiguous) text segment: IS_CODE_PTR(p)
391 and static closures in the (single, contiguous) data segment: IS_DATA_PTR(p)
393 Plan A can fail for two reasons:
394 * In many environments (eg. dynamic loading),
395 text and data aren't in a single contiguous range.
396 * When we compile through vanilla C (no mangling) we sometimes
397 can't guaranteee to put info tables in the text section. This
398 happens eg. on MacOS where the C compiler refuses to put const
399 data in the text section if it has any code pointers in it
400 (which info tables do *only* when we're compiling without
401 TABLES_NEXT_TO_CODE).
403 Hence, Plan B: (compile-via-C-with-mangling, or native code generation)
404 Put a zero word before each static closure.
405 When compiling to native code, or via C-with-mangling, info tables
406 are laid out "backwards" from the address specified in the info pointer
407 (the entry code goes forward from the info pointer). Hence, the word
408 before the one referenced the info pointer is part of the info table,
409 and is guaranteed non-zero.
411 For reasons nobody seems to fully understand, the statically-allocated tables
412 of INTLIKE and CHARLIKE closures can't have this zero word, so we
413 have to test separately for them.
415 Plan B fails altogether for the compile-through-vanilla-C route, because
416 info tables aren't laid out backwards.
419 Hence, Plan C: (unregisterised, compile-through-vanilla-C route only)
420 If we didn't manage to get info tables into the text section, then
421 we can distinguish between a static closure pointer and an info
422 pointer as follows: the first word of an info table is a code pointer,
423 and therefore in text space, whereas the first word of a closure pointer
424 is an info pointer, and therefore not. Shazam!
428 /* When working with Win32 DLLs, static closures are identified by
429 being prefixed with a zero word. This is needed so that we can
430 distinguish between pointers to static closures and (reversed!)
433 This 'scheme' breaks down for closure tables such as CHARLIKE,
434 so we catch these separately.
436 LOOKS_LIKE_STATIC_CLOSURE()
437 - discriminates between static closures and info tbls
438 (needed by LOOKS_LIKE_GHC_INFO() below - [Win32 DLLs only.])
440 - distinguishes between static and heap allocated data.
442 #if defined(ENABLE_WIN32_DLL_SUPPORT)
443 /* definitely do not enable for mingw DietHEP */
444 #define LOOKS_LIKE_STATIC(r) (!(HEAP_ALLOCED(r)))
446 /* Tiresome predicates needed to check for pointers into the closure tables */
447 #define IS_CHARLIKE_CLOSURE(p) \
448 ( (P_)(p) >= (P_)stg_CHARLIKE_closure && \
449 (char*)(p) <= ((char*)stg_CHARLIKE_closure + \
450 (MAX_CHARLIKE-MIN_CHARLIKE) * sizeof(StgIntCharlikeClosure)) )
451 #define IS_INTLIKE_CLOSURE(p) \
452 ( (P_)(p) >= (P_)stg_INTLIKE_closure && \
453 (char*)(p) <= ((char*)stg_INTLIKE_closure + \
454 (MAX_INTLIKE-MIN_INTLIKE) * sizeof(StgIntCharlikeClosure)) )
456 #define LOOKS_LIKE_STATIC_CLOSURE(r) (((*(((unsigned long *)(r))-1)) == 0) || IS_CHARLIKE_CLOSURE(r) || IS_INTLIKE_CLOSURE(r))
458 #define LOOKS_LIKE_STATIC(r) IS_DATA_PTR(r)
459 #define LOOKS_LIKE_STATIC_CLOSURE(r) IS_DATA_PTR(r)
463 /* -----------------------------------------------------------------------------
464 Macros for distinguishing infotables from closures.
466 You'd think it'd be easy to tell an info pointer from a closure pointer:
467 closures live on the heap and infotables are in read only memory. Right?
468 Wrong! Static closures live in read only memory and Hugs allocates
469 infotables for constructors on the (writable) C heap.
470 -------------------------------------------------------------------------- */
472 /* not accurate by any means, but stops the assertions failing... */
473 /* TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO TODO */
474 #define IS_HUGS_CONSTR_INFO(info) IS_USER_PTR(info)
476 /* LOOKS_LIKE_GHC_INFO is called moderately often during GC, but
477 * Certainly not as often as HEAP_ALLOCED.
479 #ifdef TEXT_BEFORE_HEAP /* needed for mingw DietHEP */
480 # define LOOKS_LIKE_GHC_INFO(info) IS_CODE_PTR(info)
482 # define LOOKS_LIKE_GHC_INFO(info) (!HEAP_ALLOCED(info) \
483 && !LOOKS_LIKE_STATIC_CLOSURE(info))
487 /* -----------------------------------------------------------------------------
488 Macros for calculating how big a closure will be (used during allocation)
489 -------------------------------------------------------------------------- */
491 /* ToDo: replace unsigned int by nat. The only fly in the ointment is that
492 * nat comes from Rts.h which many folk dont include. Sigh!
494 static __inline__ StgOffset AP_sizeW ( unsigned int n_args )
495 { return sizeofW(StgAP_UPD) + n_args; }
497 static __inline__ StgOffset PAP_sizeW ( unsigned int n_args )
498 { return sizeofW(StgPAP) + n_args; }
500 static __inline__ StgOffset CONSTR_sizeW( unsigned int p, unsigned int np )
501 { return sizeofW(StgHeader) + p + np; }
503 static __inline__ StgOffset THUNK_SELECTOR_sizeW ( void )
504 { return sizeofW(StgHeader) + MIN_UPD_SIZE; }
506 static __inline__ StgOffset BLACKHOLE_sizeW ( void )
507 { return sizeofW(StgHeader) + MIN_UPD_SIZE; }
509 /* --------------------------------------------------------------------------
511 * ------------------------------------------------------------------------*/
513 static __inline__ StgOffset sizeW_fromITBL( const StgInfoTable* itbl )
514 { return sizeofW(StgClosure)
515 + sizeofW(StgPtr) * itbl->layout.payload.ptrs
516 + sizeofW(StgWord) * itbl->layout.payload.nptrs; }
518 static __inline__ StgOffset pap_sizeW( StgPAP* x )
519 { return PAP_sizeW(x->n_args); }
521 static __inline__ StgOffset arr_words_sizeW( StgArrWords* x )
522 { return sizeofW(StgArrWords) + x->words; }
524 static __inline__ StgOffset mut_arr_ptrs_sizeW( StgMutArrPtrs* x )
525 { return sizeofW(StgMutArrPtrs) + x->ptrs; }
527 static __inline__ StgWord tso_sizeW ( StgTSO *tso )
528 { return TSO_STRUCT_SIZEW + tso->stack_size; }