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fix bytecode-reading time-complexity bug

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When a tree marshaled to bytecode form has many shared pieces,
the unmarshaling process can lose track of the sharing in one
place and traverse too much of the structure as pieces are
loaded.
This commit is contained in:
Matthew Flatt 2016-01-01 11:48:41 -07:00
parent 8b7f5bc046
commit d3bb9d0412
3 changed files with 75 additions and 20 deletions
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4
racket/src/racket/src/mzmark_read.inc
View File

@ -50,6 +50,7 @@ static int mark_cport_MARK(void *p, struct NewGC *gc) {
gcMARK2(cp->ht, gc);
gcMARK2(cp->ut, gc);
gcMARK2(cp->symtab, gc);
gcMARK2(cp->symtab_entries, gc);
gcMARK2(cp->relto, gc);
gcMARK2(cp->magic_sym, gc);
gcMARK2(cp->magic_val, gc);
@ -73,6 +74,7 @@ static int mark_cport_FIXUP(void *p, struct NewGC *gc) {
gcFIXUP2(cp->ht, gc);
gcFIXUP2(cp->ut, gc);
gcFIXUP2(cp->symtab, gc);
gcFIXUP2(cp->symtab_entries, gc);
gcFIXUP2(cp->relto, gc);
gcFIXUP2(cp->magic_sym, gc);
gcFIXUP2(cp->magic_val, gc);
@ -195,6 +197,7 @@ static int mark_delay_load_MARK(void *p, struct NewGC *gc) {
Scheme_Load_Delay *ld = (Scheme_Load_Delay *)p;
gcMARK2(ld->path, gc);
gcMARK2(ld->symtab, gc);
gcMARK2(ld->symtab_entries, gc);
gcMARK2(ld->shared_offsets, gc);
gcMARK2(ld->relto, gc);
gcMARK2(ld->ut, gc);
@ -215,6 +218,7 @@ static int mark_delay_load_FIXUP(void *p, struct NewGC *gc) {
Scheme_Load_Delay *ld = (Scheme_Load_Delay *)p;
gcFIXUP2(ld->path, gc);
gcFIXUP2(ld->symtab, gc);
gcFIXUP2(ld->symtab_entries, gc);
gcFIXUP2(ld->shared_offsets, gc);
gcFIXUP2(ld->relto, gc);
gcFIXUP2(ld->ut, gc);

2
racket/src/racket/src/mzmarksrc.c
View File

@ -2274,6 +2274,7 @@ mark_cport {
gcMARK2(cp->ht, gc);
gcMARK2(cp->ut, gc);
gcMARK2(cp->symtab, gc);
gcMARK2(cp->symtab_entries, gc);
gcMARK2(cp->relto, gc);
gcMARK2(cp->magic_sym, gc);
gcMARK2(cp->magic_val, gc);
@ -2312,6 +2313,7 @@ mark_delay_load {
Scheme_Load_Delay *ld = (Scheme_Load_Delay *)p;
gcMARK2(ld->path, gc);
gcMARK2(ld->symtab, gc);
gcMARK2(ld->symtab_entries, gc);
gcMARK2(ld->shared_offsets, gc);
gcMARK2(ld->relto, gc);
gcMARK2(ld->ut, gc);

77
racket/src/racket/src/read.c
View File

@ -2079,6 +2079,7 @@ static Scheme_Object *resolve_references(Scheme_Object *obj,
Scheme_Object *top,
Scheme_Hash_Table *dht,
Scheme_Hash_Table *tht,
Scheme_Hash_Table *self_contained_ht,
int clone,
int tail_depth);
@ -2089,7 +2090,8 @@ static Scheme_Object *resolve_k(void)
Scheme_Object *port = (Scheme_Object *)p->ku.k.p2;
Scheme_Object *top = (Scheme_Object *)p->ku.k.p5;
Scheme_Hash_Table *dht = (Scheme_Hash_Table *)p->ku.k.p3;
Scheme_Hash_Table *tht = (Scheme_Hash_Table *)p->ku.k.p4;
Scheme_Hash_Table *tht = (Scheme_Hash_Table *)SCHEME_CAR((Scheme_Object *)p->ku.k.p4);
Scheme_Hash_Table *self_contained_ht = (Scheme_Hash_Table *)SCHEME_CDR((Scheme_Object *)p->ku.k.p4);
p->ku.k.p1 = NULL;
p->ku.k.p2 = NULL;
@ -2097,7 +2099,7 @@ static Scheme_Object *resolve_k(void)
p->ku.k.p4 = NULL;
p->ku.k.p5 = NULL;
return resolve_references(o, port, top, dht, tht, p->ku.k.i1, p->ku.k.i2);
return resolve_references(o, port, top, dht, tht, self_contained_ht, p->ku.k.i1, p->ku.k.i2);
}
#endif
@ -2106,6 +2108,7 @@ static Scheme_Object *resolve_references(Scheme_Object *obj,
Scheme_Object *top,
Scheme_Hash_Table *dht,
Scheme_Hash_Table *tht,
Scheme_Hash_Table *self_contained_ht,
int clone,
int tail_depth)
{
@ -2120,7 +2123,9 @@ static Scheme_Object *resolve_references(Scheme_Object *obj,
p->ku.k.p2 = (void *)port;
p->ku.k.p5 = (void *)top;
p->ku.k.p3 = (void *)dht;
p->ku.k.p4 = (void *)tht;
result = scheme_make_pair((Scheme_Object *)tht,
(Scheme_Object *)self_contained_ht);
p->ku.k.p4 = (void *)result;
p->ku.k.i1 = clone;
p->ku.k.i2 = tail_depth;
return scheme_handle_stack_overflow(resolve_k);
@ -2149,6 +2154,10 @@ static Scheme_Object *resolve_references(Scheme_Object *obj,
}
}
if (self_contained_ht
&& scheme_hash_get(self_contained_ht, obj))
return obj;
result = scheme_hash_get(dht, obj);
if (result) {
if (SCHEME_PAIRP(result)) {
@ -2168,12 +2177,14 @@ static Scheme_Object *resolve_references(Scheme_Object *obj,
result = scheme_make_pair(scheme_false, scheme_false);
scheme_hash_set(dht, obj, result);
rr = resolve_references(SCHEME_CAR(obj), port, top, dht, tht, clone, tail_depth + 1);
rr = resolve_references(SCHEME_CAR(obj), port, top, dht, tht, self_contained_ht,
clone, tail_depth + 1);
SCHEME_CAR(result) = rr;
scheme_hash_set(tht, result, scheme_make_integer(tail_depth));
rr = resolve_references(SCHEME_CDR(obj), port, top, dht, tht, clone, tail_depth);
rr = resolve_references(SCHEME_CDR(obj), port, top, dht, tht, self_contained_ht,
clone, tail_depth);
SCHEME_CDR(result) = rr;
scheme_hash_set(tht, result, NULL);
@ -2195,7 +2206,8 @@ static Scheme_Object *resolve_references(Scheme_Object *obj,
}
scheme_hash_set(dht, obj, result);
rr = resolve_references(SCHEME_BOX_VAL(obj), port, top, dht, tht, clone, tail_depth + 1);
rr = resolve_references(SCHEME_BOX_VAL(obj), port, top, dht, tht, self_contained_ht,
clone, tail_depth + 1);
SCHEME_BOX_VAL(result) = rr;
if (clone
@ -2227,7 +2239,8 @@ static Scheme_Object *resolve_references(Scheme_Object *obj,
rr = prev_rr;
} else {
prev_v = SCHEME_VEC_ELS(obj)[i];
rr = resolve_references(prev_v, port, top, dht, tht, clone, tail_depth + 1);
rr = resolve_references(prev_v, port, top, dht, tht, self_contained_ht,
clone, tail_depth + 1);
if (!SAME_OBJ(prev_v, rr))
diff = 1;
prev_rr = rr;
@ -2280,7 +2293,8 @@ static Scheme_Object *resolve_references(Scheme_Object *obj,
result = (Scheme_Object *)t;
scheme_hash_set(dht, obj, result);
lst = resolve_references(lst, port, top, dht, tht, clone, tail_depth + 1);
lst = resolve_references(lst, port, top, dht, tht, self_contained_ht,
clone, tail_depth + 1);
for (; SCHEME_PAIRP(lst); lst = SCHEME_CDR(lst)) {
a = SCHEME_CAR(lst);
@ -2312,7 +2326,8 @@ static Scheme_Object *resolve_references(Scheme_Object *obj,
}
orig_l = l;
l = resolve_references(l, port, top, dht, tht, clone, tail_depth + 1);
l = resolve_references(l, port, top, dht, tht, self_contained_ht,
clone, tail_depth + 1);
if (SAME_OBJ(l, orig_l)) {
result = obj;
@ -2347,7 +2362,8 @@ static Scheme_Object *resolve_references(Scheme_Object *obj,
diff = 0;
for (i = 0; i < c; i++) {
prev_v = ((Scheme_Structure *)result)->slots[i];
v = resolve_references(prev_v, port, top, dht, tht, clone, tail_depth + 1);
v = resolve_references(prev_v, port, top, dht, tht, self_contained_ht,
clone, tail_depth + 1);
if (!SAME_OBJ(prev_v, v))
diff = 1;
((Scheme_Structure *)result)->slots[i] = v;
@ -2491,12 +2507,12 @@ _internal_read(Scheme_Object *port, Scheme_Object *stxsrc, int crc, int cant_fai
tht = scheme_make_hash_table(SCHEME_hash_ptr);
if (v)
v = resolve_references(v, port, NULL, dht, tht, clone, 0);
v = resolve_references(v, port, NULL, dht, tht, NULL, clone, 0);
/* In case some placeholders were introduced by #;: */
v2 = scheme_hash_get(*ht, unresolved_uninterned_symbol);
if (v2)
resolve_references(v2, port, NULL, dht, tht, clone, 0);
resolve_references(v2, port, NULL, dht, tht, NULL, clone, 0);
if (!v)
*ht = NULL;
@ -2585,6 +2601,7 @@ Scheme_Object *scheme_resolve_placeholders(Scheme_Object *obj)
return resolve_references(obj, NULL, obj,
scheme_make_hash_table(SCHEME_hash_ptr),
scheme_make_hash_table(SCHEME_hash_ptr),
NULL,
1, 0);
}
@ -4491,6 +4508,7 @@ typedef struct Scheme_Load_Delay {
uintptr_t symtab_size;
Scheme_Object **symtab;
intptr_t *shared_offsets;
Scheme_Hash_Table *symtab_entries; /* `symtab` content to be skipped by resolve_references */
Scheme_Object *relto;
Scheme_Unmarshal_Tables *ut;
struct CPort *current_rp;
@ -4520,6 +4538,7 @@ typedef struct CPort {
Scheme_Object *symtab_refs;
Scheme_Unmarshal_Tables *ut;
Scheme_Object **symtab;
Scheme_Hash_Table *symtab_entries;
Scheme_Object *magic_sym, *magic_val;
Scheme_Object *relto;
intptr_t *shared_offsets;
@ -4771,6 +4790,20 @@ static Scheme_Object *read_compact_escape(CPort *port)
return read_escape_from_string(s, len, port->relto, port->ht);
}
static void record_symtab_self_contained(Scheme_Hash_Table *symtab_entries, Scheme_Object *v)
{
if (SCHEME_PAIRP(v)
|| SCHEME_BOXP(v)
|| SCHEME_VECTORP(v)
|| SCHEME_HASHTRP(v)
|| SCHEME_STRUCTP(v)) {
/* Register `v` as a value that is shared through the symbol table,
so that later calls to resolve_references() can avoid re-traversing
the value. (Otherwise, bytecode reading can become quadratic-time.) */
scheme_hash_set(symtab_entries, v, scheme_true);
}
}
static Scheme_Object *resolve_symtab_refs(Scheme_Object *v, CPort *port)
{
Scheme_Object *l;
@ -4784,6 +4817,7 @@ static Scheme_Object *resolve_symtab_refs(Scheme_Object *v, CPort *port)
v = resolve_references(v, port->orig_port, NULL,
scheme_make_hash_table(SCHEME_hash_ptr),
scheme_make_hash_table(SCHEME_hash_ptr),
port->symtab_entries,
0, 0);
l = SCHEME_CDR(v);
@ -4791,9 +4825,10 @@ static Scheme_Object *resolve_symtab_refs(Scheme_Object *v, CPort *port)
l = port->symtab_refs;
for (; !SCHEME_NULLP(l); l = SCHEME_CDR(l)) {
if (v)
if (v) {
port->symtab[SCHEME_INT_VAL(SCHEME_CAR(SCHEME_CAR(l)))] = SCHEME_CDR(SCHEME_CAR(l));
else {
record_symtab_self_contained(port->symtab_entries, SCHEME_CDR(SCHEME_CAR(l)));
} else {
/* interrupted; discard partial constructions */
port->symtab[SCHEME_INT_VAL(SCHEME_CAR(SCHEME_CAR(l)))] = NULL;
}
@ -5042,6 +5077,7 @@ static Scheme_Object *read_compact(CPort *port, int use_stack)
v = resolve_references(v, port->orig_port, NULL,
scheme_make_hash_table(SCHEME_hash_ptr),
scheme_make_hash_table(SCHEME_hash_ptr),
port->symtab_entries,
0, 0);
}
@ -5529,6 +5565,7 @@ static Scheme_Object *read_compact_quote(CPort *port, int embedded)
v = resolve_references(v, port->orig_port, NULL,
scheme_make_hash_table(SCHEME_hash_ptr),
scheme_make_hash_table(SCHEME_hash_ptr),
port->symtab_entries,
0, 0);
return v;
@ -5864,6 +5901,14 @@ static Scheme_Object *read_compiled(Scheme_Object *port,
rp->symtab = symtab;
rp->unsafe_ok = params->can_read_unsafe;
{
Scheme_Hash_Table *se_ht;
se_ht = scheme_make_hash_table(SCHEME_hash_ptr);
rp->symtab_entries = se_ht;
if (delay_info)
delay_info->symtab_entries = se_ht;
}
config = scheme_current_config();
dir = scheme_get_param(config, MZCONFIG_LOAD_DIRECTORY);
@ -6151,6 +6196,7 @@ Scheme_Object *scheme_load_delayed_code(int _which, Scheme_Load_Delay *_delay_in
rp->ut = delay_info->ut;
rp->unsafe_ok = delay_info->unsafe_ok;
rp->bytecode_hash = delay_info->bytecode_hash;
rp->symtab_entries = delay_info->symtab_entries;
if (delay_info->ut)
delay_info->ut->rp = rp;
@ -6207,10 +6253,12 @@ Scheme_Object *scheme_load_delayed_code(int _which, Scheme_Load_Delay *_delay_in
v = resolve_references(v, port, NULL,
scheme_make_hash_table(SCHEME_hash_ptr),
scheme_make_hash_table(SCHEME_hash_ptr),
delay_info->symtab_entries,
0, 0);
}
delay_info->symtab[which] = v;
record_symtab_self_contained(delay_info->symtab_entries, v);
return v;
} else {
@ -6392,6 +6440,7 @@ static Scheme_Object *readtable_call(int w_char, int ch, Scheme_Object *proc, Re
v = resolve_references(v, port, NULL,
scheme_make_hash_table(SCHEME_hash_ptr),
scheme_make_hash_table(SCHEME_hash_ptr),
NULL,
1, 0);
}