1 /* -----------------------------------------------------------------------------
2 * $Id: Storage.h,v 1.23 2001/01/26 14:17:01 simonpj 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 /* Temporary measure to ensure we retain all the dynamically-loaded CAFs */
86 extern void markCafs( void );
89 /* -----------------------------------------------------------------------------
90 Generational garbage collection support
92 recordMutable(StgPtr p) Informs the garbage collector that a
93 previously immutable object has
94 become (permanently) mutable. Used
95 by thawArray and similar.
97 updateWithIndirection(p1,p2) Updates the object at p1 with an
98 indirection pointing to p2. This is
99 normally called for objects in an old
100 generation (>0) when they are updated.
102 updateWithPermIndirection(p1,p2) As above but uses a permanent indir.
104 -------------------------------------------------------------------------- */
106 /* ToDo: shouldn't recordMutable and recordOldToNewPtrs acquire some
107 * kind of lock in the SMP case?
110 recordMutable(StgMutClosure *p)
115 ASSERT(p->header.info == &stg_WHITEHOLE_info || closure_MUTABLE(p));
117 ASSERT(closure_MUTABLE(p));
121 if (bd->gen->no > 0) {
122 p->mut_link = bd->gen->mut_list;
123 bd->gen->mut_list = p;
128 recordOldToNewPtrs(StgMutClosure *p)
133 if (bd->gen->no > 0) {
134 p->mut_link = bd->gen->mut_once_list;
135 bd->gen->mut_once_list = p;
140 #define updateWithIndirection(info, p1, p2) \
144 bd = Bdescr((P_)p1); \
145 if (bd->gen->no == 0) { \
146 ((StgInd *)p1)->indirectee = p2; \
147 SET_INFO(p1,&stg_IND_info); \
148 TICK_UPD_NEW_IND(); \
150 ((StgIndOldGen *)p1)->indirectee = p2; \
151 if (info != &stg_BLACKHOLE_BQ_info) { \
152 ACQUIRE_LOCK(&sm_mutex); \
153 ((StgIndOldGen *)p1)->mut_link = bd->gen->mut_once_list; \
154 bd->gen->mut_once_list = (StgMutClosure *)p1; \
155 RELEASE_LOCK(&sm_mutex); \
157 SET_INFO(p1,&stg_IND_OLDGEN_info); \
158 TICK_UPD_OLD_IND(); \
163 /* In the DEBUG case, we also zero out the slop of the old closure,
164 * so that the sanity checker can tell where the next closure is.
166 #define updateWithIndirection(info, p1, p2) \
170 bd = Bdescr((P_)p1); \
171 if (bd->gen->no == 0) { \
172 ((StgInd *)p1)->indirectee = p2; \
173 SET_INFO(p1,&stg_IND_info); \
174 TICK_UPD_NEW_IND(); \
176 if (info != &stg_BLACKHOLE_BQ_info) { \
178 StgInfoTable *inf = get_itbl(p1); \
179 nat np = inf->layout.payload.ptrs, \
180 nw = inf->layout.payload.nptrs, i; \
181 for (i = np; i < np + nw; i++) { \
182 ((StgClosure *)p1)->payload[i] = 0; \
185 ACQUIRE_LOCK(&sm_mutex); \
186 ((StgIndOldGen *)p1)->mut_link = bd->gen->mut_once_list; \
187 bd->gen->mut_once_list = (StgMutClosure *)p1; \
188 RELEASE_LOCK(&sm_mutex); \
190 ((StgIndOldGen *)p1)->indirectee = p2; \
191 SET_INFO(p1,&stg_IND_OLDGEN_info); \
192 TICK_UPD_OLD_IND(); \
197 /* Static objects all live in the oldest generation
199 #define updateWithStaticIndirection(info, p1, p2) \
201 ASSERT( ((StgMutClosure*)p1)->mut_link == NULL ); \
203 ACQUIRE_LOCK(&sm_mutex); \
204 ((StgMutClosure *)p1)->mut_link = oldest_gen->mut_once_list; \
205 oldest_gen->mut_once_list = (StgMutClosure *)p1; \
206 RELEASE_LOCK(&sm_mutex); \
208 ((StgInd *)p1)->indirectee = p2; \
209 SET_INFO((StgInd *)p1, &stg_IND_STATIC_info); \
210 TICK_UPD_STATIC_IND(); \
213 #if defined(TICKY_TICKY) || defined(PROFILING)
215 updateWithPermIndirection(const StgInfoTable *info, StgClosure *p1, StgClosure *p2)
220 if (bd->gen->no == 0) {
221 ((StgInd *)p1)->indirectee = p2;
222 SET_INFO(p1,&stg_IND_PERM_info);
223 TICK_UPD_NEW_PERM_IND(p1);
225 ((StgIndOldGen *)p1)->indirectee = p2;
226 if (info != &stg_BLACKHOLE_BQ_info) {
227 ACQUIRE_LOCK(&sm_mutex);
228 ((StgIndOldGen *)p1)->mut_link = bd->gen->mut_once_list;
229 bd->gen->mut_once_list = (StgMutClosure *)p1;
230 RELEASE_LOCK(&sm_mutex);
232 SET_INFO(p1,&stg_IND_OLDGEN_PERM_info);
233 TICK_UPD_OLD_PERM_IND();
238 /* -----------------------------------------------------------------------------
239 The CAF table - used to let us revert CAFs
240 -------------------------------------------------------------------------- */
242 #if defined(INTERPRETER)
243 typedef struct StgCAFTabEntry_ {
245 StgInfoTable* origItbl;
248 extern void addToECafTable ( StgClosure* closure, StgInfoTable* origItbl );
249 extern void clearECafTable ( void );
251 extern StgCAF* ecafList;
252 extern StgCAFTabEntry* ecafTable;
253 extern StgInt usedECafTable;
254 extern StgInt sizeECafTable;
258 void printMutOnceList(generation *gen);
259 void printMutableList(generation *gen);
262 /* --------------------------------------------------------------------------
263 Address space layout macros
264 --------------------------------------------------------------------------
266 Here are the assumptions GHC makes about address space layout.
267 Broadly, it thinks there are three sections:
269 CODE Read-only. Contains code and read-only data (such as
273 DATA Read-write data. Contains static closures (and on some
274 architectures, info tables too)
276 HEAP Dynamically-allocated closures
278 Three macros identify these three areas:
279 IS_CODE(p), IS_DATA(p), HEAP_ALLOCED(p)
281 HEAP_ALLOCED is called FOR EVERY SINGLE CLOSURE during GC.
284 Implementation of HEAP_ALLOCED
285 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
286 Concerning HEAP, most of the time (certainly under [Static] and [GHCi],
287 we ensure that the heap is allocated above some fixed address HEAP_BASE
288 (defined in MBlock.h). In this case we set TEXT_BEFORE_HEAP, and we
289 get a nice fast test.
291 Sometimes we can't be quite sure. For example in Windows, we can't
292 fix where our heap address space comes from. In this case we un-set
293 TEXT_BEFORE_HEAP. That makes it more expensive to test whether a pointer
294 comes from the HEAP section, because we need to look at the allocator's
295 address maps (see HEAP_ALLOCED macro)
297 Implementation of CODE and DATA
298 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
299 Concerning CODE and DATA, there are three main regimes:
301 [Static] Totally The segments are contiguous, and laid out
302 statically linked exactly as above
304 [GHCi] Static, GHCi may load new modules, but it knows the
305 except for GHCi address map, so for any given address it can
306 still tell which section it belongs to
308 [DLL] OS-supported Chunks of CODE and DATA may be mixed in
309 dynamic loading the address space, and we can't tell how
312 For the [Static] case, we assume memory is laid out like this
313 (in order of increasing addresses)
317 TEXT_SECTION_END_MARKER (usually _etext)
319 DATA_SECTION_END_MARKER (usually _end)
324 For the [GHCi] case, we have to consult GHCi's dynamic linker's
325 address maps, which is done by macros
326 is_dynamically_loaded_code_or_rodata_ptr
327 is_dynamically_loaded_code_or_rwdata_ptr
329 For the [DLL] case, IS_CODE and IS_DATA are really not usable at all.
333 #undef TEXT_BEFORE_HEAP
334 #ifndef mingw32_TARGET_OS
335 #define TEXT_BEFORE_HEAP 1
338 extern void* TEXT_SECTION_END_MARKER_DECL;
339 extern void* DATA_SECTION_END_MARKER_DECL;
341 #if defined(INTERPRETER) || defined(GHCI)
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 #define IS_CODE_PTR(p) ((P_)(p) < (P_)&TEXT_SECTION_END_MARKER)
352 #define IS_DATA_PTR(p) ((P_)(p) >= (P_)&TEXT_SECTION_END_MARKER && (P_)(p) < (P_)&DATA_SECTION_END_MARKER)
353 #define IS_USER_PTR(p) ((P_)(p) >= (P_)&DATA_SECTION_END_MARKER)
356 /* The HEAP_ALLOCED test below is called FOR EVERY SINGLE CLOSURE
357 * during GC. It needs to be FAST.
359 * BEWARE: when we're dynamically loading code (for GHCi), make sure
360 * that we don't load any code above HEAP_BASE, or this test won't work.
362 #ifdef TEXT_BEFORE_HEAP
363 # define HEAP_ALLOCED(x) ((StgPtr)(x) >= (StgPtr)(HEAP_BASE))
365 extern int is_heap_alloced(const void* x);
366 # define HEAP_ALLOCED(x) (is_heap_alloced(x))
370 /* --------------------------------------------------------------------------
371 Macros for distinguishing data pointers from code pointers
372 --------------------------------------------------------------------------
376 The garbage collector needs to make some critical distinctions between pointers.
377 In particular we need
379 LOOKS_LIKE_GHC_INFO(p) p points to an info table
381 For both of these macros, p is
382 *either* a pointer to a closure (static or heap allocated)
383 *or* a return address on the (Haskell) stack
385 (Return addresses are in fact info-pointers, so that the Haskell stack
386 looks very like a chunk of heap.)
388 The garbage collector uses LOOKS_LIKE_GHC_INFO when walking the stack, as it
389 walks over the "pending arguments" on its way to the next return address.
390 It is called moderately often, but not as often as HEAP_ALLOCED
395 LOOKS_LIKE_GHC_INFO is more complicated because of the need to distinguish
396 between static closures and info tables. It's a known portability problem.
397 We have three approaches:
399 Plan A: Address-space partitioning.
400 Keep info tables in the (single, contiguous) text segment: IS_CODE_PTR(p)
401 and static closures in the (single, contiguous) data segment: IS_DATA_PTR(p)
403 Plan A can fail for two reasons:
404 * In many environments (eg. dynamic loading),
405 text and data aren't in a single contiguous range.
406 * When we compile through vanilla C (no mangling) we sometimes
407 can't guaranteee to put info tables in the text section. This
408 happens eg. on MacOS where the C compiler refuses to put const
409 data in the text section if it has any code pointers in it
410 (which info tables do *only* when we're compiling without
411 TABLES_NEXT_TO_CODE).
413 Hence, Plan B: (compile-via-C-with-mangling, or native code generation)
414 Put a zero word before each static closure.
415 When compiling to native code, or via C-with-mangling, info tables
416 are laid out "backwards" from the address specified in the info pointer
417 (the entry code goes forward from the info pointer). Hence, the word
418 before the one referenced the info pointer is part of the info table,
419 and is guaranteed non-zero.
421 For reasons nobody seems to fully understand, the statically-allocated tables
422 of INTLIKE and CHARLIKE closures can't have this zero word, so we
423 have to test separately for them.
425 Plan B fails altogether for the compile-through-vanilla-C route, because
426 info tables aren't laid out backwards.
429 Hence, Plan C: (unregisterised, compile-through-vanilla-C route only)
430 If we didn't manage to get info tables into the text section, then
431 we can distinguish between a static closure pointer and an info
432 pointer as follows: the first word of an info table is a code pointer,
433 and therefore in text space, whereas the first word of a closure pointer
434 is an info pointer, and therefore not. Shazam!
438 /* When working with Win32 DLLs, static closures are identified by
439 being prefixed with a zero word. This is needed so that we can
440 distinguish between pointers to static closures and (reversed!)
443 This 'scheme' breaks down for closure tables such as CHARLIKE,
444 so we catch these separately.
446 LOOKS_LIKE_STATIC_CLOSURE()
447 - discriminates between static closures and info tbls
448 (needed by LOOKS_LIKE_GHC_INFO() below - [Win32 DLLs only.])
450 - distinguishes between static and heap allocated data.
452 #if defined(ENABLE_WIN32_DLL_SUPPORT) && !defined(INTERPRETER)
453 /* definitely do not enable for mingw DietHEP */
454 #define LOOKS_LIKE_STATIC(r) (!(HEAP_ALLOCED(r)))
456 /* Tiresome predicates needed to check for pointers into the closure tables */
457 #define IS_CHARLIKE_CLOSURE(p) \
458 ( (P_)(p) >= (P_)stg_CHARLIKE_closure && \
459 (char*)(p) <= ((char*)stg_CHARLIKE_closure + \
460 (MAX_CHARLIKE-MIN_CHARLIKE) * sizeof(StgIntCharlikeClosure)) )
461 #define IS_INTLIKE_CLOSURE(p) \
462 ( (P_)(p) >= (P_)stg_INTLIKE_closure && \
463 (char*)(p) <= ((char*)stg_INTLIKE_closure + \
464 (MAX_INTLIKE-MIN_INTLIKE) * sizeof(StgIntCharlikeClosure)) )
466 #define LOOKS_LIKE_STATIC_CLOSURE(r) (((*(((unsigned long *)(r))-1)) == 0) || IS_CHARLIKE_CLOSURE(r) || IS_INTLIKE_CLOSURE(r))
468 #define LOOKS_LIKE_STATIC(r) IS_DATA_PTR(r)
469 #define LOOKS_LIKE_STATIC_CLOSURE(r) IS_DATA_PTR(r)
473 /* -----------------------------------------------------------------------------
474 Macros for distinguishing infotables from closures.
476 You'd think it'd be easy to tell an info pointer from a closure pointer:
477 closures live on the heap and infotables are in read only memory. Right?
478 Wrong! Static closures live in read only memory and Hugs allocates
479 infotables for constructors on the (writable) C heap.
480 -------------------------------------------------------------------------- */
483 # ifdef USE_MINIINTERPRETER
484 /* yoiks: one of the dreaded pointer equality tests */
485 # define IS_HUGS_CONSTR_INFO(info) \
486 (((StgInfoTable *)(info))->entry == (StgFunPtr)&Hugs_CONSTR_entry)
488 # define IS_HUGS_CONSTR_INFO(info) 0 /* ToDo: more than mildly bogus */
491 /* not accurate by any means, but stops the assertions failing... */
492 # define IS_HUGS_CONSTR_INFO(info) IS_USER_PTR(info)
494 # define IS_HUGS_CONSTR_INFO(info) 0 /* ToDo: more than mildly bogus */
497 /* LOOKS_LIKE_GHC_INFO is called moderately often during GC, but
498 * Certainly not as often as HEAP_ALLOCED.
500 #ifdef TEXT_BEFORE_HEAP /* needed for mingw DietHEP */
501 # define LOOKS_LIKE_GHC_INFO(info) IS_CODE_PTR(info)
503 # define LOOKS_LIKE_GHC_INFO(info) (!HEAP_ALLOCED(info) \
504 && !LOOKS_LIKE_STATIC_CLOSURE(info))
508 /* -----------------------------------------------------------------------------
509 Macros for calculating how big a closure will be (used during allocation)
510 -------------------------------------------------------------------------- */
512 /* ToDo: replace unsigned int by nat. The only fly in the ointment is that
513 * nat comes from Rts.h which many folk dont include. Sigh!
515 static __inline__ StgOffset AP_sizeW ( unsigned int n_args )
516 { return sizeofW(StgAP_UPD) + n_args; }
518 static __inline__ StgOffset PAP_sizeW ( unsigned int n_args )
519 { return sizeofW(StgPAP) + n_args; }
521 static __inline__ StgOffset CONSTR_sizeW( unsigned int p, unsigned int np )
522 { return sizeofW(StgHeader) + p + np; }
524 static __inline__ StgOffset THUNK_SELECTOR_sizeW ( void )
525 { return sizeofW(StgHeader) + MIN_UPD_SIZE; }
527 static __inline__ StgOffset BLACKHOLE_sizeW ( void )
528 { return sizeofW(StgHeader) + MIN_UPD_SIZE; }
530 static __inline__ StgOffset CAF_sizeW ( void )
531 { return sizeofW(StgCAF); }
533 /* --------------------------------------------------------------------------
535 * ------------------------------------------------------------------------*/
537 static __inline__ StgOffset sizeW_fromITBL( const StgInfoTable* itbl )
538 { return sizeofW(StgClosure)
539 + sizeofW(StgPtr) * itbl->layout.payload.ptrs
540 + sizeofW(StgWord) * itbl->layout.payload.nptrs; }
542 static __inline__ StgOffset pap_sizeW( StgPAP* x )
543 { return PAP_sizeW(x->n_args); }
545 static __inline__ StgOffset arr_words_sizeW( StgArrWords* x )
546 { return sizeofW(StgArrWords) + x->words; }
548 static __inline__ StgOffset mut_arr_ptrs_sizeW( StgMutArrPtrs* x )
549 { return sizeofW(StgMutArrPtrs) + x->ptrs; }
551 static __inline__ StgWord tso_sizeW ( StgTSO *tso )
552 { return TSO_STRUCT_SIZEW + tso->stack_size; }