static void thread_static( StgClosure* p ) { const StgInfoTable *info; // keep going until we've threaded all the objects on the linked // list... while (p != END_OF_STATIC_LIST) { info = get_itbl(p); switch (info->type) { case IND_STATIC: thread(&((StgInd *)p)->indirectee); p = *IND_STATIC_LINK(p); continue; case THUNK_STATIC: p = *THUNK_STATIC_LINK(p); continue; case FUN_STATIC: p = *FUN_STATIC_LINK(p); continue; case CONSTR_STATIC: p = *STATIC_LINK(info,p); continue; default: barf("thread_static: strange closure %d", (int)(info->type)); } } }
/* Check the static objects list. */ void checkStaticObjects ( StgClosure* static_objects ) { StgClosure *p = static_objects; const StgInfoTable *info; while (p != END_OF_STATIC_OBJECT_LIST) { p = UNTAG_STATIC_LIST_PTR(p); checkClosure(p); info = get_itbl(p); switch (info->type) { case IND_STATIC: { const StgClosure *indirectee; indirectee = UNTAG_CONST_CLOSURE(((StgIndStatic *)p)->indirectee); ASSERT(LOOKS_LIKE_CLOSURE_PTR(indirectee)); ASSERT(LOOKS_LIKE_INFO_PTR((StgWord)indirectee->header.info)); p = *IND_STATIC_LINK((StgClosure *)p); break; } case THUNK_STATIC: p = *THUNK_STATIC_LINK((StgClosure *)p); break; case FUN_STATIC: p = *STATIC_LINK(info,(StgClosure *)p); break; case CONSTR: case CONSTR_NOCAF: case CONSTR_1_0: case CONSTR_2_0: case CONSTR_1_1: p = *STATIC_LINK(info,(StgClosure *)p); break; default: barf("checkStaticObjetcs: strange closure %p (%s)", p, info_type(p)); } } }
/* Check the static objects list. */ void checkStaticObjects ( StgClosure* static_objects ) { StgClosure *p = static_objects; StgInfoTable *info; while (p != END_OF_STATIC_LIST) { checkClosure(p); info = get_itbl(p); switch (info->type) { case IND_STATIC: { StgClosure *indirectee = UNTAG_CLOSURE(((StgIndStatic *)p)->indirectee); ASSERT(LOOKS_LIKE_CLOSURE_PTR(indirectee)); ASSERT(LOOKS_LIKE_INFO_PTR((StgWord)indirectee->header.info)); p = *IND_STATIC_LINK((StgClosure *)p); break; } case THUNK_STATIC: p = *THUNK_STATIC_LINK((StgClosure *)p); break; case FUN_STATIC: p = *FUN_STATIC_LINK((StgClosure *)p); break; case CONSTR_STATIC: p = *STATIC_LINK(info,(StgClosure *)p); break; default: barf("checkStaticObjetcs: strange closure %p (%s)", p, #ifndef HaLVM_TARGET_OS info_type(p) #else "[HaLVM has no info_type()]" #endif ); } } }
REGPARM1 GNUC_ATTR_HOT void evacuate(StgClosure **p) { bdescr *bd = NULL; nat gen_no; StgClosure *q; const StgInfoTable *info; StgWord tag; q = *p; loop: /* The tag and the pointer are split, to be merged after evacing */ tag = GET_CLOSURE_TAG(q); q = UNTAG_CLOSURE(q); ASSERTM(LOOKS_LIKE_CLOSURE_PTR(q), "invalid closure, info=%p", q->header.info); if (!HEAP_ALLOCED_GC(q)) { if (!major_gc) return; info = get_itbl(q); switch (info->type) { case THUNK_STATIC: if (info->srt_bitmap != 0) { evacuate_static_object(THUNK_STATIC_LINK((StgClosure *)q), q); } return; case FUN_STATIC: if (info->srt_bitmap != 0) { evacuate_static_object(FUN_STATIC_LINK((StgClosure *)q), q); } return; case IND_STATIC: /* If q->saved_info != NULL, then it's a revertible CAF - it'll be * on the CAF list, so don't do anything with it here (we'll * scavenge it later). */ evacuate_static_object(IND_STATIC_LINK((StgClosure *)q), q); return; case CONSTR_STATIC: evacuate_static_object(STATIC_LINK(info,(StgClosure *)q), q); return; case CONSTR_NOCAF_STATIC: /* no need to put these on the static linked list, they don't need * to be scavenged. */ return; default: barf("evacuate(static): strange closure type %d", (int)(info->type)); } } bd = Bdescr((P_)q); if ((bd->flags & (BF_LARGE | BF_MARKED | BF_EVACUATED)) != 0) { // pointer into to-space: just return it. It might be a pointer // into a generation that we aren't collecting (> N), or it // might just be a pointer into to-space. The latter doesn't // happen often, but allowing it makes certain things a bit // easier; e.g. scavenging an object is idempotent, so it's OK to // have an object on the mutable list multiple times. if (bd->flags & BF_EVACUATED) { // We aren't copying this object, so we have to check // whether it is already in the target generation. (this is // the write barrier). if (bd->gen_no < gct->evac_gen_no) { gct->failed_to_evac = rtsTrue; TICK_GC_FAILED_PROMOTION(); } return; } /* evacuate large objects by re-linking them onto a different list. */ if (bd->flags & BF_LARGE) { evacuate_large((P_)q); return; } /* If the object is in a gen that we're compacting, then we * need to use an alternative evacuate procedure. */ if (!is_marked((P_)q,bd)) { mark((P_)q,bd); push_mark_stack((P_)q); } return; } gen_no = bd->dest_no; info = q->header.info; if (IS_FORWARDING_PTR(info)) { /* Already evacuated, just return the forwarding address. * HOWEVER: if the requested destination generation (gct->evac_gen) is * older than the actual generation (because the object was * already evacuated to a younger generation) then we have to * set the gct->failed_to_evac flag to indicate that we couldn't * manage to promote the object to the desired generation. */ /* * Optimisation: the check is fairly expensive, but we can often * shortcut it if either the required generation is 0, or the * current object (the EVACUATED) is in a high enough generation. * We know that an EVACUATED always points to an object in the * same or an older generation. gen is the lowest generation that the * current object would be evacuated to, so we only do the full * check if gen is too low. */ StgClosure *e = (StgClosure*)UN_FORWARDING_PTR(info); *p = TAG_CLOSURE(tag,e); if (gen_no < gct->evac_gen_no) { // optimisation if (Bdescr((P_)e)->gen_no < gct->evac_gen_no) { gct->failed_to_evac = rtsTrue; TICK_GC_FAILED_PROMOTION(); } } return; } switch (INFO_PTR_TO_STRUCT(info)->type) { case WHITEHOLE: goto loop; // For ints and chars of low value, save space by replacing references to // these with closures with references to common, shared ones in the RTS. // // * Except when compiling into Windows DLLs which don't support cross-package // data references very well. // case CONSTR_0_1: { #if defined(COMPILING_WINDOWS_DLL) copy_tag_nolock(p,info,q,sizeofW(StgHeader)+1,gen_no,tag); #else StgWord w = (StgWord)q->payload[0]; if (info == Czh_con_info && // unsigned, so always true: (StgChar)w >= MIN_CHARLIKE && (StgChar)w <= MAX_CHARLIKE) { *p = TAG_CLOSURE(tag, (StgClosure *)CHARLIKE_CLOSURE((StgChar)w) ); } else if (info == Izh_con_info && (StgInt)w >= MIN_INTLIKE && (StgInt)w <= MAX_INTLIKE) { *p = TAG_CLOSURE(tag, (StgClosure *)INTLIKE_CLOSURE((StgInt)w) ); } else { copy_tag_nolock(p,info,q,sizeofW(StgHeader)+1,gen_no,tag); } #endif return; } case FUN_0_1: case FUN_1_0: case CONSTR_1_0: copy_tag_nolock(p,info,q,sizeofW(StgHeader)+1,gen_no,tag); return; case THUNK_1_0: case THUNK_0_1: copy(p,info,q,sizeofW(StgThunk)+1,gen_no); return; case THUNK_1_1: case THUNK_2_0: case THUNK_0_2: #ifdef NO_PROMOTE_THUNKS #error bitrotted #endif copy(p,info,q,sizeofW(StgThunk)+2,gen_no); return; case FUN_1_1: case FUN_2_0: case FUN_0_2: case CONSTR_1_1: case CONSTR_2_0: copy_tag_nolock(p,info,q,sizeofW(StgHeader)+2,gen_no,tag); return; case CONSTR_0_2: copy_tag_nolock(p,info,q,sizeofW(StgHeader)+2,gen_no,tag); return; case THUNK: copy(p,info,q,thunk_sizeW_fromITBL(INFO_PTR_TO_STRUCT(info)),gen_no); return; case FUN: case CONSTR: copy_tag_nolock(p,info,q,sizeW_fromITBL(INFO_PTR_TO_STRUCT(info)),gen_no,tag); return; case BLACKHOLE: { StgClosure *r; const StgInfoTable *i; r = ((StgInd*)q)->indirectee; if (GET_CLOSURE_TAG(r) == 0) { i = r->header.info; if (IS_FORWARDING_PTR(i)) { r = (StgClosure *)UN_FORWARDING_PTR(i); i = r->header.info; } if (i == &stg_TSO_info || i == &stg_WHITEHOLE_info || i == &stg_BLOCKING_QUEUE_CLEAN_info || i == &stg_BLOCKING_QUEUE_DIRTY_info) { copy(p,info,q,sizeofW(StgInd),gen_no); return; } ASSERT(i != &stg_IND_info); } q = r; *p = r; goto loop; } case MUT_VAR_CLEAN: case MUT_VAR_DIRTY: case MVAR_CLEAN: case MVAR_DIRTY: case TVAR: case BLOCKING_QUEUE: case WEAK: case PRIM: case MUT_PRIM: copy(p,info,q,sizeW_fromITBL(INFO_PTR_TO_STRUCT(info)),gen_no); return; case BCO: copy(p,info,q,bco_sizeW((StgBCO *)q),gen_no); return; case THUNK_SELECTOR: eval_thunk_selector(p, (StgSelector *)q, rtsTrue); return; case IND: // follow chains of indirections, don't evacuate them q = ((StgInd*)q)->indirectee; *p = q; goto loop; case RET_BCO: case RET_SMALL: case RET_BIG: case UPDATE_FRAME: case UNDERFLOW_FRAME: case STOP_FRAME: case CATCH_FRAME: case CATCH_STM_FRAME: case CATCH_RETRY_FRAME: case ATOMICALLY_FRAME: // shouldn't see these barf("evacuate: stack frame at %p\n", q); case PAP: copy(p,info,q,pap_sizeW((StgPAP*)q),gen_no); return; case AP: copy(p,info,q,ap_sizeW((StgAP*)q),gen_no); return; case AP_STACK: copy(p,info,q,ap_stack_sizeW((StgAP_STACK*)q),gen_no); return; case ARR_WORDS: // just copy the block copy(p,info,q,arr_words_sizeW((StgArrBytes *)q),gen_no); return; case MUT_ARR_PTRS_CLEAN: case MUT_ARR_PTRS_DIRTY: case MUT_ARR_PTRS_FROZEN: case MUT_ARR_PTRS_FROZEN0: // just copy the block copy(p,info,q,mut_arr_ptrs_sizeW((StgMutArrPtrs *)q),gen_no); return; case SMALL_MUT_ARR_PTRS_CLEAN: case SMALL_MUT_ARR_PTRS_DIRTY: case SMALL_MUT_ARR_PTRS_FROZEN: case SMALL_MUT_ARR_PTRS_FROZEN0: // just copy the block copy(p,info,q,small_mut_arr_ptrs_sizeW((StgSmallMutArrPtrs *)q),gen_no); return; case TSO: copy(p,info,q,sizeofW(StgTSO),gen_no); return; case STACK: { StgStack *stack = (StgStack *)q; /* To evacuate a small STACK, we need to adjust the stack pointer */ { StgStack *new_stack; StgPtr r, s; rtsBool mine; mine = copyPart(p,(StgClosure *)stack, stack_sizeW(stack), sizeofW(StgStack), gen_no); if (mine) { new_stack = (StgStack *)*p; move_STACK(stack, new_stack); for (r = stack->sp, s = new_stack->sp; r < stack->stack + stack->stack_size;) { *s++ = *r++; } } return; } } case TREC_CHUNK: copy(p,info,q,sizeofW(StgTRecChunk),gen_no); return; default: barf("evacuate: strange closure type %d", (int)(INFO_PTR_TO_STRUCT(info)->type)); } barf("evacuate"); }
void pruneSparkQueue (Capability *cap) { SparkPool *pool; StgClosurePtr spark, tmp, *elements; nat n, pruned_sparks; // stats only StgWord botInd,oldBotInd,currInd; // indices in array (always < size) const StgInfoTable *info; n = 0; pruned_sparks = 0; pool = cap->sparks; // it is possible that top > bottom, indicating an empty pool. We // fix that here; this is only necessary because the loop below // assumes it. if (pool->top > pool->bottom) pool->top = pool->bottom; // Take this opportunity to reset top/bottom modulo the size of // the array, to avoid overflow. This is only possible because no // stealing is happening during GC. pool->bottom -= pool->top & ~pool->moduloSize; pool->top &= pool->moduloSize; pool->topBound = pool->top; debugTrace(DEBUG_sparks, "markSparkQueue: current spark queue len=%ld; (hd=%ld; tl=%ld)", sparkPoolSize(pool), pool->bottom, pool->top); ASSERT_WSDEQUE_INVARIANTS(pool); elements = (StgClosurePtr *)pool->elements; /* We have exclusive access to the structure here, so we can reset bottom and top counters, and prune invalid sparks. Contents are copied in-place if they are valuable, otherwise discarded. The routine uses "real" indices t and b, starts by computing them as the modulus size of top and bottom, Copying: At the beginning, the pool structure can look like this: ( bottom % size >= top % size , no wrap-around) t b ___________***********_________________ or like this ( bottom % size < top % size, wrap-around ) b t ***********__________****************** As we need to remove useless sparks anyway, we make one pass between t and b, moving valuable content to b and subsequent cells (wrapping around when the size is reached). b t ***********OOO_______XX_X__X?********** ^____move?____/ After this movement, botInd becomes the new bottom, and old bottom becomes the new top index, both as indices in the array size range. */ // starting here currInd = (pool->top) & (pool->moduloSize); // mod // copies of evacuated closures go to space from botInd on // we keep oldBotInd to know when to stop oldBotInd = botInd = (pool->bottom) & (pool->moduloSize); // mod // on entry to loop, we are within the bounds ASSERT( currInd < pool->size && botInd < pool->size ); while (currInd != oldBotInd ) { /* must use != here, wrap-around at size subtle: loop not entered if queue empty */ /* check element at currInd. if valuable, evacuate and move to botInd, otherwise move on */ spark = elements[currInd]; // We have to be careful here: in the parallel GC, another // thread might evacuate this closure while we're looking at it, // so grab the info pointer just once. if (GET_CLOSURE_TAG(spark) != 0) { // Tagged pointer is a value, so the spark has fizzled. It // probably never happens that we get a tagged pointer in // the spark pool, because we would have pruned the spark // during the previous GC cycle if it turned out to be // evaluated, but it doesn't hurt to have this check for // robustness. pruned_sparks++; cap->sparks_fizzled++; } else { info = spark->header.info; if (IS_FORWARDING_PTR(info)) { tmp = (StgClosure*)UN_FORWARDING_PTR(info); /* if valuable work: shift inside the pool */ if (closure_SHOULD_SPARK(tmp)) { elements[botInd] = tmp; // keep entry (new address) botInd++; n++; } else { pruned_sparks++; // discard spark cap->sparks_fizzled++; } } else if (HEAP_ALLOCED(spark)) { if ((Bdescr((P_)spark)->flags & BF_EVACUATED)) { if (closure_SHOULD_SPARK(spark)) { elements[botInd] = spark; // keep entry (new address) botInd++; n++; } else { pruned_sparks++; // discard spark cap->sparks_fizzled++; } } else { pruned_sparks++; // discard spark cap->sparks_gcd++; } } else { if (INFO_PTR_TO_STRUCT(info)->type == THUNK_STATIC) { if (*THUNK_STATIC_LINK(spark) != NULL) { elements[botInd] = spark; // keep entry (new address) botInd++; n++; } else { pruned_sparks++; // discard spark cap->sparks_gcd++; } } else { pruned_sparks++; // discard spark cap->sparks_fizzled++; } } } currInd++; // in the loop, we may reach the bounds, and instantly wrap around ASSERT( currInd <= pool->size && botInd <= pool->size ); if ( currInd == pool->size ) { currInd = 0; } if ( botInd == pool->size ) { botInd = 0; } } // while-loop over spark pool elements ASSERT(currInd == oldBotInd); pool->top = oldBotInd; // where we started writing pool->topBound = pool->top; pool->bottom = (oldBotInd <= botInd) ? botInd : (botInd + pool->size); // first free place we did not use (corrected by wraparound) debugTrace(DEBUG_sparks, "pruned %d sparks", pruned_sparks); debugTrace(DEBUG_sparks, "new spark queue len=%ld; (hd=%ld; tl=%ld)", sparkPoolSize(pool), pool->bottom, pool->top); ASSERT_WSDEQUE_INVARIANTS(pool); }