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);
}