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reuse existing typemap search for method overwrite detection (#48968)
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It does not really make sense to scan the tree twice, when we already
will extra this info near completely from the intersection search.
The cost was small, but non-negligible.
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@vtjnash
vtjnash authored Mar 16, 2023
1 parent 551f303 commit 38d9d83
Showing 1 changed file with 38 additions and 24 deletions.
62 changes: 38 additions & 24 deletions src/gf.c
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Original file line number Diff line number Diff line change
Expand Up @@ -207,6 +207,9 @@ JL_DLLEXPORT jl_value_t *jl_specializations_lookup(jl_method_t *m, jl_value_t *t

JL_DLLEXPORT jl_value_t *jl_methtable_lookup(jl_methtable_t *mt, jl_value_t *type, size_t world)
{
// TODO: this is sort of an odd lookup strategy (and the only user of
// jl_typemap_assoc_by_type with subtype=0), while normally jl_gf_invoke_lookup would be
// expected to be used instead
struct jl_typemap_assoc search = {type, world, NULL, 0, ~(size_t)0};
jl_typemap_entry_t *sf = jl_typemap_assoc_by_type(jl_atomic_load_relaxed(&mt->defs), &search, /*offs*/0, /*subtype*/0);
if (!sf)
Expand Down Expand Up @@ -1379,7 +1382,9 @@ struct matches_env {
struct typemap_intersection_env match;
jl_typemap_entry_t *newentry;
jl_value_t *shadowed;
jl_typemap_entry_t *replaced;
};

static int get_intersect_visitor(jl_typemap_entry_t *oldentry, struct typemap_intersection_env *closure0)
{
struct matches_env *closure = container_of(closure0, struct matches_env, match);
Expand All @@ -1390,13 +1395,17 @@ static int get_intersect_visitor(jl_typemap_entry_t *oldentry, struct typemap_in
// also be careful not to try to scan something from the current dump-reload though
return 1;
jl_method_t *oldmethod = oldentry->func.method;
if (closure->match.issubty // e.g. jl_subtype(closure->newentry.sig, oldentry->sig)
&& jl_subtype(oldmethod->sig, (jl_value_t*)closure->newentry->sig)) { // e.g. jl_type_equal(closure->newentry->sig, oldentry->sig)
closure->replaced = oldentry;
}
if (closure->shadowed == NULL)
closure->shadowed = (jl_value_t*)jl_alloc_vec_any(0);
jl_array_ptr_1d_push((jl_array_t*)closure->shadowed, (jl_value_t*)oldmethod);
return 1;
}

static jl_value_t *get_intersect_matches(jl_typemap_t *defs, jl_typemap_entry_t *newentry)
static jl_value_t *get_intersect_matches(jl_typemap_t *defs, jl_typemap_entry_t *newentry, jl_typemap_entry_t **replaced)
{
jl_tupletype_t *type = newentry->sig;
jl_tupletype_t *ttypes = (jl_tupletype_t*)jl_unwrap_unionall((jl_value_t*)type);
Expand All @@ -1411,9 +1420,12 @@ static jl_value_t *get_intersect_matches(jl_typemap_t *defs, jl_typemap_entry_t
}
struct matches_env env = {{get_intersect_visitor, (jl_value_t*)type, va,
/* .ti = */ NULL, /* .env = */ jl_emptysvec, /* .issubty = */ 0},
/* .newentry = */ newentry, /* .shadowed */ NULL};
/* .newentry = */ newentry, /* .shadowed */ NULL, /* .replaced */ NULL};
JL_GC_PUSH3(&env.match.env, &env.match.ti, &env.shadowed);
jl_typemap_intersection_visitor(defs, 0, &env.match);
env.match.env = NULL;
env.match.ti = NULL;
*replaced = env.replaced;
JL_GC_POP();
return env.shadowed;
}
Expand Down Expand Up @@ -1735,8 +1747,9 @@ static jl_typemap_entry_t *do_typemap_search(jl_methtable_t *mt JL_PROPAGATES_RO
}
#endif

static void jl_method_table_invalidate(jl_methtable_t *mt, jl_typemap_entry_t *methodentry, jl_method_t *method, size_t max_world)
static void jl_method_table_invalidate(jl_methtable_t *mt, jl_typemap_entry_t *methodentry, size_t max_world)
{
jl_method_t *method = methodentry->func.method;
assert(!method->is_for_opaque_closure);
method->deleted_world = methodentry->max_world = max_world;
// drop this method from mt->cache
Expand All @@ -1760,16 +1773,18 @@ static void jl_method_table_invalidate(jl_methtable_t *mt, jl_typemap_entry_t *m
}
// Invalidate the backedges
int invalidated = 0;
jl_svec_t *specializations = jl_atomic_load_relaxed(&methodentry->func.method->specializations);
jl_svec_t *specializations = jl_atomic_load_relaxed(&method->specializations);
l = jl_svec_len(specializations);
for (i = 0; i < l; i++) {
jl_method_instance_t *mi = (jl_method_instance_t*)jl_svecref(specializations, i);
if ((jl_value_t*)mi != jl_nothing) {
invalidated = 1;
invalidate_external(mi, methodentry->max_world);
invalidate_backedges(&do_nothing_with_codeinst, mi, methodentry->max_world, "jl_method_table_disable");
invalidate_external(mi, max_world);
invalidate_backedges(&do_nothing_with_codeinst, mi, max_world, "jl_method_table_disable");
}
}
// XXX: this might have resolved an ambiguity, for which we have not tracked the edge here,
// and thus now introduce a mistake into inference
if (invalidated && _jl_debug_method_invalidation) {
jl_array_ptr_1d_push(_jl_debug_method_invalidation, (jl_value_t*)method);
jl_value_t *loctag = jl_cstr_to_string("jl_method_table_disable");
Expand All @@ -1788,7 +1803,7 @@ JL_DLLEXPORT void jl_method_table_disable(jl_methtable_t *mt, jl_method_t *metho
JL_LOCK(&mt->writelock);
// Narrow the world age on the method to make it uncallable
size_t world = jl_atomic_fetch_add(&jl_world_counter, 1);
jl_method_table_invalidate(mt, methodentry, method, world);
jl_method_table_invalidate(mt, methodentry, world);
JL_UNLOCK(&mt->writelock);
}

Expand Down Expand Up @@ -1866,22 +1881,21 @@ JL_DLLEXPORT void jl_method_table_insert(jl_methtable_t *mt, jl_method_t *method
jl_typemap_entry_t *newentry = NULL;
JL_GC_PUSH7(&oldvalue, &oldmi, &newentry, &loctag, &isect, &isect2, &isect3);
JL_LOCK(&mt->writelock);
// first find if we have an existing entry to delete
struct jl_typemap_assoc search = {(jl_value_t*)type, method->primary_world, NULL, 0, ~(size_t)0};
jl_typemap_entry_t *oldentry = jl_typemap_assoc_by_type(jl_atomic_load_relaxed(&mt->defs), &search, /*offs*/0, /*subtype*/0);
// then add our new entry
// add our new entry
newentry = jl_typemap_alloc((jl_tupletype_t*)type, simpletype, jl_emptysvec,
(jl_value_t*)method, method->primary_world, method->deleted_world);
jl_typemap_insert(&mt->defs, (jl_value_t*)mt, newentry, 0);
if (oldentry) {
jl_method_t *m = oldentry->func.method;
method_overwrite(newentry, m);
jl_method_table_invalidate(mt, oldentry, m, max_world);
jl_typemap_entry_t *replaced = NULL;
// then check what entries we replaced
oldvalue = get_intersect_matches(jl_atomic_load_relaxed(&mt->defs), newentry, &replaced);
int invalidated = 0;
if (replaced) {
oldvalue = (jl_value_t*)replaced;
invalidated = 1;
method_overwrite(newentry, replaced->func.method);
jl_method_table_invalidate(mt, replaced, max_world);
}
else {
oldvalue = get_intersect_matches(jl_atomic_load_relaxed(&mt->defs), newentry);

int invalidated = 0;
jl_method_t *const *d;
size_t j, n;
if (oldvalue == NULL) {
Expand Down Expand Up @@ -2033,13 +2047,13 @@ JL_DLLEXPORT void jl_method_table_insert(jl_methtable_t *mt, jl_method_t *method
}
}
}
if (invalidated && _jl_debug_method_invalidation) {
jl_array_ptr_1d_push(_jl_debug_method_invalidation, (jl_value_t*)method);
loctag = jl_cstr_to_string("jl_method_table_insert");
jl_array_ptr_1d_push(_jl_debug_method_invalidation, loctag);
}
update_max_args(mt, type);
}
if (invalidated && _jl_debug_method_invalidation) {
jl_array_ptr_1d_push(_jl_debug_method_invalidation, (jl_value_t*)method);
loctag = jl_cstr_to_string("jl_method_table_insert");
jl_array_ptr_1d_push(_jl_debug_method_invalidation, loctag);
}
update_max_args(mt, type);
JL_UNLOCK(&mt->writelock);
JL_GC_POP();
}
Expand Down

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