static intnat large_alloc_sweep(struct caml_heap_state* local) {
large_alloc* a = local->unswept_large;
if (!a) return 0;
local->unswept_large = a->next;
header_t hd = *(header_t*)((char*)a + LARGE_ALLOC_HEADER_SZ);
if (Has_status_hd(hd, global.GARBAGE)) {
local->large_bytes_allocated -= Bhsize_hd(hd);
free(a);
} else {
a->next = local->swept_large;
local->swept_large = a;
}
return Whsize_hd(hd);
}
static void caml_oldify_one (value v, value *p)
{
value result;
header_t hd;
mlsize_t sz, i;
tag_t tag;
tail_call:
if (Is_block (v) && Is_young (v)){
Assert (Hp_val (v) >= caml_domain_state->young_ptr);
hd = Hd_val (v);
stat_live_bytes += Bhsize_hd(hd);
if (Is_promoted_hd (hd)) {
*p = caml_addrmap_lookup(&caml_domain_state->remembered_set->promotion, v);
} else if (hd == 0){ /* If already forwarded */
*p = Op_val(v)[0]; /* then forward pointer is first field. */
}else{
tag = Tag_hd (hd);
if (tag < Infix_tag){
value field0;
sz = Wosize_hd (hd);
result = alloc_shared (sz, tag);
*p = result;
if (tag == Stack_tag) {
memcpy((void*)result, (void*)v, sizeof(value) * sz);
Hd_val (v) = 0;
Op_val(v)[0] = result;
Op_val(v)[1] = oldify_todo_list;
oldify_todo_list = v;
} else {
field0 = Op_val(v)[0];
Hd_val (v) = 0; /* Set forward flag */
Op_val(v)[0] = result; /* and forward pointer. */
if (sz > 1){
Op_val (result)[0] = field0;
Op_val (result)[1] = oldify_todo_list; /* Add this block */
oldify_todo_list = v; /* to the "to do" list. */
}else{
Assert (sz == 1);
p = Op_val(result);
v = field0;
goto tail_call;
}
}
}else if (tag >= No_scan_tag){
sz = Wosize_hd (hd);
result = alloc_shared(sz, tag);
for (i = 0; i < sz; i++) Op_val (result)[i] = Op_val(v)[i];
Hd_val (v) = 0; /* Set forward flag */
Op_val (v)[0] = result; /* and forward pointer. */
*p = result;
}else if (tag == Infix_tag){
mlsize_t offset = Infix_offset_hd (hd);
caml_oldify_one (v - offset, p); /* Cannot recurse deeper than 1. */
*p += offset;
} else{
value f = Forward_val (v);
tag_t ft = 0;
int vv = 1;
Assert (tag == Forward_tag);
if (Is_block (f)){
if (Is_young (f)){
vv = 1;
ft = Tag_val (Hd_val (f) == 0 ? Op_val (f)[0] : f);
}else{
vv = 1;
if (vv){
ft = Tag_val (f);
}
}
}
if (!vv || ft == Forward_tag || ft == Lazy_tag || ft == Double_tag){
/* Do not short-circuit the pointer. Copy as a normal block. */
Assert (Wosize_hd (hd) == 1);
result = alloc_shared (1, Forward_tag);
*p = result;
Hd_val (v) = 0; /* Set (GC) forward flag */
Op_val (v)[0] = result; /* and forward pointer. */
p = Op_val (result);
v = f;
goto tail_call;
}else{
v = f; /* Follow the forwarding */
goto tail_call; /* then oldify. */
}
}
}
}else{
*p = v;
}
}
static void do_compaction_r (CAML_R)
{
char *ch, *chend;
Assert (caml_gc_phase == Phase_idle);
caml_gc_message (0x10, "Compacting heap...\n", 0);
#ifdef DEBUG
caml_heap_check_r (ctx);
#endif
/* First pass: encode all noninfix headers. */
{
ch = caml_heap_start;
while (ch != NULL){
header_t *p = (header_t *) ch;
chend = ch + Chunk_size (ch);
while ((char *) p < chend){
header_t hd = Hd_hp (p);
mlsize_t sz = Wosize_hd (hd);
if (Is_blue_hd (hd)){
/* Free object. Give it a string tag. */
Hd_hp (p) = Make_ehd (sz, String_tag, 3);
}else{ Assert (Is_white_hd (hd));
/* Live object. Keep its tag. */
Hd_hp (p) = Make_ehd (sz, Tag_hd (hd), 3);
}
p += Whsize_wosize (sz);
}
ch = Chunk_next (ch);
}
}
/* Second pass: invert pointers.
Link infix headers in each block in an inverted list of inverted lists.
Don't forget roots and weak pointers. */
{
/* Invert roots first because the threads library needs some heap
data structures to find its roots. Fortunately, it doesn't need
the headers (see above). */
caml_do_roots_r (ctx, invert_root_r);
caml_final_do_weak_roots_r (ctx, invert_root_r);
ch = caml_heap_start;
while (ch != NULL){
word *p = (word *) ch;
chend = ch + Chunk_size (ch);
while ((char *) p < chend){
word q = *p;
size_t sz, i;
tag_t t;
word *infixes;
while (Ecolor (q) == 0) q = * (word *) q;
sz = Whsize_ehd (q);
t = Tag_ehd (q);
if (t == Infix_tag){
/* Get the original header of this block. */
infixes = p + sz;
q = *infixes;
while (Ecolor (q) != 3) q = * (word *) (q & ~(uintnat)3);
sz = Whsize_ehd (q);
t = Tag_ehd (q);
}
if (t < No_scan_tag){
for (i = 1; i < sz; i++) invert_pointer_at_r (ctx, &(p[i]));
}
p += sz;
}
ch = Chunk_next (ch);
}
/* Invert weak pointers. */
{
value *pp = &caml_weak_list_head;
value p;
word q;
size_t sz, i;
while (1){
p = *pp;
if (p == (value) NULL) break;
q = Hd_val (p);
while (Ecolor (q) == 0) q = * (word *) q;
sz = Wosize_ehd (q);
for (i = 1; i < sz; i++){
if (Field (p,i) != caml_weak_none){
invert_pointer_at_r (ctx, (word *) &(Field (p,i)));
}
}
invert_pointer_at_r (ctx, (word *) pp);
pp = &Field (p, 0);
}
}
}
/* Third pass: reallocate virtually; revert pointers; decode headers.
Rebuild infix headers. */
{
init_compact_allocate_r (ctx);
ch = caml_heap_start;
while (ch != NULL){
word *p = (word *) ch;
chend = ch + Chunk_size (ch);
while ((char *) p < chend){
word q = *p;
if (Ecolor (q) == 0 || Tag_ehd (q) == Infix_tag){
/* There were (normal or infix) pointers to this block. */
size_t sz;
tag_t t;
char *newadr;
word *infixes = NULL;
while (Ecolor (q) == 0) q = * (word *) q;
sz = Whsize_ehd (q);
t = Tag_ehd (q);
if (t == Infix_tag){
/* Get the original header of this block. */
infixes = p + sz;
q = *infixes; Assert (Ecolor (q) == 2);
while (Ecolor (q) != 3) q = * (word *) (q & ~(uintnat)3);
sz = Whsize_ehd (q);
t = Tag_ehd (q);
}
newadr = compact_allocate_r (ctx, Bsize_wsize (sz));
q = *p;
while (Ecolor (q) == 0){
word next = * (word *) q;
* (word *) q = (word) Val_hp (newadr);
q = next;
}
*p = Make_header (Wosize_whsize (sz), t, Caml_white);
if (infixes != NULL){
/* Rebuild the infix headers and revert the infix pointers. */
while (Ecolor ((word) infixes) != 3){
infixes = (word *) ((word) infixes & ~(uintnat) 3);
q = *infixes;
while (Ecolor (q) == 2){
word next;
q = (word) q & ~(uintnat) 3;
next = * (word *) q;
* (word *) q = (word) Val_hp ((word *) newadr + (infixes - p));
q = next;
} Assert (Ecolor (q) == 1 || Ecolor (q) == 3);
*infixes = Make_header (infixes - p, Infix_tag, Caml_white);
infixes = (word *) q;
}
}
p += sz;
}else{ Assert (Ecolor (q) == 3);
/* This is guaranteed only if caml_compact_heap was called after a
nonincremental major GC: Assert (Tag_ehd (q) == String_tag);
*/
/* No pointers to the header and no infix header:
the object was free. */
*p = Make_header (Wosize_ehd (q), Tag_ehd (q), Caml_blue);
p += Whsize_ehd (q);
}
}
ch = Chunk_next (ch);
}
}
/* Fourth pass: reallocate and move objects.
Use the exact same allocation algorithm as pass 3. */
{
init_compact_allocate_r (ctx);
ch = caml_heap_start;
while (ch != NULL){
word *p = (word *) ch;
chend = ch + Chunk_size (ch);
while ((char *) p < chend){
word q = *p;
if (Color_hd (q) == Caml_white){
size_t sz = Bhsize_hd (q);
char *newadr = compact_allocate_r (ctx, sz);
memmove (newadr, p, sz);
p += Wsize_bsize (sz);
}else{
Assert (Color_hd (q) == Caml_blue);
p += Whsize_hd (q);
}
}
ch = Chunk_next (ch);
}
}
/* Shrink the heap if needed. */
{
/* Find the amount of live data and the unshrinkable free space. */
asize_t live = 0;
asize_t free = 0;
asize_t wanted;
ch = caml_heap_start;
while (ch != NULL){
if (Chunk_alloc (ch) != 0){
live += Wsize_bsize (Chunk_alloc (ch));
free += Wsize_bsize (Chunk_size (ch) - Chunk_alloc (ch));
}
ch = Chunk_next (ch);
}
/* Add up the empty chunks until there are enough, then remove the
other empty chunks. */
wanted = caml_percent_free * (live / 100 + 1);
ch = caml_heap_start;
while (ch != NULL){
char *next_chunk = Chunk_next (ch); /* Chunk_next (ch) will be erased */
if (Chunk_alloc (ch) == 0){
if (free < wanted){
free += Wsize_bsize (Chunk_size (ch));
}else{
caml_shrink_heap_r (ctx, ch);
}
}
ch = next_chunk;
}
}
/* Rebuild the free list. */
{
ch = caml_heap_start;
caml_fl_reset_r (ctx);
while (ch != NULL){
if (Chunk_size (ch) > Chunk_alloc (ch)){
caml_make_free_blocks_r (ctx, (value *) (ch + Chunk_alloc (ch)),
Wsize_bsize (Chunk_size(ch)-Chunk_alloc(ch)), 1,
Caml_white);
}
ch = Chunk_next (ch);
}
}
++ caml_stat_compactions;
caml_gc_message (0x10, "done.\n", 0);
}
/* Note that the tests on the tag depend on the fact that Infix_tag,
Forward_tag, and No_scan_tag are contiguous. */
static void oldify_one (void* st_v, value v, value *p)
{
struct oldify_state* st = st_v;
value result;
header_t hd;
mlsize_t sz, i;
mlsize_t infix_offset;
tag_t tag;
caml_domain_state* domain_state =
st->promote_domain ? st->promote_domain->state : Caml_state;
char* young_ptr = domain_state->young_ptr;
char* young_end = domain_state->young_end;
CAMLassert (domain_state->young_start <= domain_state->young_ptr &&
domain_state->young_ptr <= domain_state->young_end);
tail_call:
if (!(Is_block(v) && is_in_interval((value)Hp_val(v), young_ptr, young_end))) {
/* not a minor block */
*p = v;
return;
}
infix_offset = 0;
do {
hd = Hd_val (v);
if (hd == 0) {
/* already forwarded, forward pointer is first field. */
*p = Op_val(v)[0] + infix_offset;
return;
}
tag = Tag_hd (hd);
if (tag == Infix_tag) {
/* Infix header, retry with the real block */
CAMLassert (infix_offset == 0);
infix_offset = Infix_offset_hd (hd);
CAMLassert(infix_offset > 0);
v -= infix_offset;
}
} while (tag == Infix_tag);
if (((value)Hp_val(v)) > st->oldest_promoted) {
st->oldest_promoted = (value)Hp_val(v);
}
if (tag == Cont_tag) {
struct stack_info* stk = Ptr_val(Op_val(v)[0]);
CAMLassert(Wosize_hd(hd) == 1 && infix_offset == 0);
result = alloc_shared(1, Cont_tag);
*p = result;
Op_val(result)[0] = Val_ptr(stk);
*Hp_val (v) = 0;
Op_val(v)[0] = result;
if (stk != NULL)
caml_scan_stack(&oldify_one, st, stk);
} else if (tag < Infix_tag) {
value field0;
sz = Wosize_hd (hd);
st->live_bytes += Bhsize_hd(hd);
result = alloc_shared (sz, tag);
*p = result + infix_offset;
field0 = Op_val(v)[0];
CAMLassert (!Is_debug_tag(field0));
*Hp_val (v) = 0; /* Set forward flag */
Op_val(v)[0] = result; /* and forward pointer. */
if (sz > 1){
Op_val (result)[0] = field0;
Op_val (result)[1] = st->todo_list; /* Add this block */
st->todo_list = v; /* to the "to do" list. */
}else{
CAMLassert (sz == 1);
p = Op_val(result);
v = field0;
goto tail_call;
}
} else if (tag >= No_scan_tag) {
sz = Wosize_hd (hd);
st->live_bytes += Bhsize_hd(hd);
result = alloc_shared(sz, tag);
for (i = 0; i < sz; i++) {
value curr = Op_val(v)[i];
Op_val (result)[i] = curr;
}
*Hp_val (v) = 0; /* Set forward flag */
Op_val (v)[0] = result; /* and forward pointer. */
CAMLassert (infix_offset == 0);
*p = result;
} else {
CAMLassert (tag == Forward_tag);
CAMLassert (infix_offset == 0);
value f = Forward_val (v);
tag_t ft = 0;
if (Is_block (f)) {
ft = Tag_val (Hd_val (f) == 0 ? Op_val (f)[0] : f);
}
if (ft == Forward_tag || ft == Lazy_tag || ft == Double_tag) {
/* Do not short-circuit the pointer. Copy as a normal block. */
CAMLassert (Wosize_hd (hd) == 1);
st->live_bytes += Bhsize_hd(hd);
result = alloc_shared (1, Forward_tag);
*p = result;
*Hp_val (v) = 0; /* Set (GC) forward flag */
Op_val (v)[0] = result; /* and forward pointer. */
p = Op_val (result);
v = f;
goto tail_call;
} else {
v = f; /* Follow the forwarding */
goto tail_call; /* then oldify. */
}
}
}
