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Bug #7158 » 0003-Index-LOADED_FEATURES-so-require-isn-t-so-slow.patch

Patch 3 - index for $LOADED_FEATURES - gregprice (Greg Price), 10/14/2012 01:56 PM

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ChangeLog
Tue Sep 4 14:15:18 2012 Greg Price <price@mit.edu>
* load.c (rb_feature_p, rb_provide_feature, et al.):
index $LOADED_FEATURES so that require isn't so slow.
* load.c (rb_provide_feature, get_loaded_features_index): ensure
that $LOADED_FEATURES entries are frozen strings. The user
must mutate $LOADED_FEATURES itself rather than its individual
entries.
* vm_core.h (rb_vm_struct): add fields.
* vm.c (rb_vm_mark): mark new fields.
* include/ruby/intern.h (rb_hash_clear): declare function.
* hash.c (rb_hash_clear): make function non-static.
Tue Sep 4 14:16:52 2012 Greg Price <price@mit.edu>
* array.c (rb_ary_shared_with_p): new function.
hash.c
*
*/
static VALUE
VALUE
rb_hash_clear(VALUE hash)
{
rb_hash_modify_check(hash);
include/ruby/intern.h
VALUE rb_hash_lookup2(VALUE, VALUE, VALUE);
VALUE rb_hash_fetch(VALUE, VALUE);
VALUE rb_hash_aset(VALUE, VALUE, VALUE);
VALUE rb_hash_clear(VALUE);
VALUE rb_hash_delete_if(VALUE);
VALUE rb_hash_delete(VALUE,VALUE);
typedef VALUE rb_hash_update_func(VALUE newkey, VALUE oldkey, VALUE value);
load.c
#define IS_DLEXT(e) (strcmp((e), DLEXT) == 0)
#endif
static const char *const loadable_ext[] = {
".rb", DLEXT,
#ifdef DLEXT2
......
return GET_VM()->loaded_features;
}
static void
reset_loaded_features_snapshot(void)
{
rb_vm_t *vm = GET_VM();
rb_ary_replace(vm->loaded_features_snapshot, vm->loaded_features);
}
static VALUE
get_loaded_features_index_raw(void)
{
return GET_VM()->loaded_features_index;
}
static st_table *
get_loading_table(void)
{
return GET_VM()->loading_table;
}
static void
features_index_add_single(VALUE short_feature, VALUE offset)
{
VALUE features_index, this_feature_index;
features_index = get_loaded_features_index_raw();
if ((this_feature_index = rb_hash_lookup(features_index, short_feature)) == Qnil) {
this_feature_index = rb_ary_new();
rb_hash_aset(features_index, short_feature, this_feature_index);
}
rb_ary_push(this_feature_index, offset);
}
/* Add to the loaded-features index all the required entries for
`feature`, located at `offset` in $LOADED_FEATURES. We add an
index entry at each string `short_feature` for which
feature == "#{prefix}#{short_feature}#{e}"
where `e` is empty or matches %r{^\.[^./]*$}, and `prefix` is empty
or ends in '/'. This maintains the invariant that `rb_feature_p()`
relies on for its fast lookup.
*/
static void
features_index_add(VALUE feature, VALUE offset)
{
VALUE short_feature;
const char *feature_str, *feature_end, *ext, *p;
feature_str = StringValuePtr(feature);
feature_end = feature_str + RSTRING_LEN(feature);
for (ext = feature_end; ext > feature_str; ext--)
if (*ext == '.' || *ext == '/')
break;
if (*ext != '.')
ext = NULL;
/* Now `ext` points to the only string matching %r{^\.[^./]*$} that is
at the end of `feature`, or is NULL if there is no such string. */
p = ext ? ext : feature_end;
while (1) {
p--;
while (p >= feature_str && *p != '/')
p--;
if (p < feature_str)
break;
/* Now *p == '/'. We reach this point for every '/' in `feature`. */
short_feature = rb_str_substr(feature, p + 1 - feature_str, feature_end - p - 1);
features_index_add_single(short_feature, offset);
if (ext) {
short_feature = rb_str_substr(feature, p + 1 - feature_str, ext - p - 1);
features_index_add_single(short_feature, offset);
}
}
features_index_add_single(feature, offset);
if (ext) {
short_feature = rb_str_substr(feature, 0, ext - feature_str);
features_index_add_single(short_feature, offset);
}
}
static VALUE
get_loaded_features_index(void)
{
VALUE features;
int i;
rb_vm_t *vm = GET_VM();
if (!rb_ary_shared_with_p(vm->loaded_features_snapshot, vm->loaded_features)) {
/* The sharing was broken; something (other than us in rb_provide_feature())
modified loaded_features. Rebuild the index. */
rb_hash_clear(vm->loaded_features_index);
features = vm->loaded_features;
for (i = 0; i < RARRAY_LEN(features); i++) {
VALUE entry, as_str;
as_str = entry = rb_ary_entry(features, i);
StringValue(as_str);
if (as_str != entry)
rb_ary_store(features, i, as_str);
rb_str_freeze(as_str);
features_index_add(as_str, INT2FIX(i));
}
reset_loaded_features_snapshot();
}
return vm->loaded_features_index;
}
/* This searches `load_path` for a value such that
name == "#{load_path[i]}/#{feature}"
if `feature` is a suffix of `name`, or otherwise
......
static int
rb_feature_p(const char *feature, const char *ext, int rb, int expanded, const char **fn)
{
VALUE v, features, p, load_path = 0;
VALUE features, features_index, feature_val, this_feature_index, v, p, load_path = 0;
const char *f, *e;
long i, len, elen, n;
st_table *loading_tbl;
......
type = 0;
}
features = get_loaded_features();
for (i = 0; i < RARRAY_LEN(features); ++i) {
/* This loop searches `features` for an entry such that either
"#{features[i]}" == "#{load_path[j]}/#{feature}#{e}"
for some j, or
"#{features[i]}" == "#{feature}#{e}"
Here `e` is an "allowed" extension -- either empty or one
of the extensions accepted by IS_RBEXT, IS_SOEXT, or
IS_DLEXT. Further, if `ext && rb` then `IS_RBEXT(e)`,
and if `ext && !rb` then `IS_SOEXT(e) || IS_DLEXT(e)`.
If `expanded`, then only the latter form (without
load_path[j]) is accepted. Otherwise either form is
accepted, *unless* `ext` is false and an otherwise-matching
entry of the first form is preceded by an entry of the form
"#{features[i2]}" == "#{load_path[j2]}/#{feature}#{e2}"
where `e2` matches /^\.[^./]*$/ but is not an allowed extension.
After a "distractor" entry of this form, only entries of the
form "#{feature}#{e}" are accepted.
*/
v = RARRAY_PTR(features)[i];
features_index = get_loaded_features_index();
feature_val = rb_str_new(feature, len);
this_feature_index = rb_hash_lookup(features_index, feature_val);
/* We search `features` for an entry such that either
"#{features[i]}" == "#{load_path[j]}/#{feature}#{e}"
for some j, or
"#{features[i]}" == "#{feature}#{e}"
Here `e` is an "allowed" extension -- either empty or one
of the extensions accepted by IS_RBEXT, IS_SOEXT, or
IS_DLEXT. Further, if `ext && rb` then `IS_RBEXT(e)`,
and if `ext && !rb` then `IS_SOEXT(e) || IS_DLEXT(e)`.
If `expanded`, then only the latter form (without load_path[j])
is accepted. Otherwise either form is accepted, *unless* `ext`
is false and an otherwise-matching entry of the first form is
preceded by an entry of the form
"#{features[i2]}" == "#{load_path[j2]}/#{feature}#{e2}"
where `e2` matches %r{^\.[^./]*$} but is not an allowed extension.
After a "distractor" entry of this form, only entries of the
form "#{feature}#{e}" are accepted.
In `rb_provide_feature()` and `get_loaded_features_index()` we
maintain an invariant that the array `this_feature_index` will
point to every entry in `features` which has the form
"#{prefix}#{feature}#{e}"
where `e` is empty or matches %r{^\.[^./]*$}, and `prefix` is empty
or ends in '/'. This includes both match forms above, as well
as any distractors, so we may ignore all other entries in `features`.
*/
for (i = 0; this_feature_index != Qnil && i < RARRAY_LEN(this_feature_index); i++) {
long index = FIX2LONG(rb_ary_entry(this_feature_index, i));
v = RARRAY_PTR(features)[index];
f = StringValuePtr(v);
if ((n = RSTRING_LEN(v)) < len) continue;
if (strncmp(f, feature, len) != 0) {
......
return 'r';
}
}
loading_tbl = get_loading_table();
if (loading_tbl) {
f = 0;
......
static void
rb_provide_feature(VALUE feature)
{
if (OBJ_FROZEN(get_loaded_features())) {
VALUE features;
features = get_loaded_features();
if (OBJ_FROZEN(features)) {
rb_raise(rb_eRuntimeError,
"$LOADED_FEATURES is frozen; cannot append feature");
}
rb_ary_push(get_loaded_features(), feature);
rb_str_freeze(feature);
rb_ary_push(features, feature);
features_index_add(feature, INT2FIX(RARRAY_LEN(features)-1));
reset_loaded_features_snapshot();
}
void
......
rb_define_virtual_variable("$\"", get_loaded_features, 0);
rb_define_virtual_variable("$LOADED_FEATURES", get_loaded_features, 0);
vm->loaded_features = rb_ary_new();
vm->loaded_features_snapshot = rb_ary_new();
vm->loaded_features_index = rb_hash_new();
rb_define_global_function("load", rb_f_load, -1);
rb_define_global_function("require", rb_f_require, 1);
vm.c
RUBY_MARK_UNLESS_NULL(vm->mark_object_ary);
RUBY_MARK_UNLESS_NULL(vm->load_path);
RUBY_MARK_UNLESS_NULL(vm->loaded_features);
RUBY_MARK_UNLESS_NULL(vm->loaded_features_snapshot);
RUBY_MARK_UNLESS_NULL(vm->loaded_features_index);
RUBY_MARK_UNLESS_NULL(vm->top_self);
RUBY_MARK_UNLESS_NULL(vm->coverages);
rb_gc_mark_locations(vm->special_exceptions, vm->special_exceptions + ruby_special_error_count);
vm_core.h
VALUE top_self;
VALUE load_path;
VALUE loaded_features;
VALUE loaded_features_snapshot;
VALUE loaded_features_index;
struct st_table *loading_table;
/* signal */
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