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[JAEGER] Second try at start/end iterator fast paths, bug 578756. r=dmandelin, dvander, gal

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This commit is contained in:
Brian Hackett
2010-08-12 17:26:07 -04:00
parent c1fd155b54
commit 469d338181
8 changed files with 284 additions and 46 deletions
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126
js/src/jsiter.cpp
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@@ -484,11 +484,11 @@ NativeIterator::allocateKeyIterator(JSContext *cx, uint32 slength, const AutoIdV
}
NativeIterator *
NativeIterator::allocateValueIterator(JSContext *cx, uint32 slength, const AutoValueVector &props)
NativeIterator::allocateValueIterator(JSContext *cx, const AutoValueVector &props)
{
size_t plength = props.length();
NativeIterator *ni = (NativeIterator *)
cx->malloc(sizeof(NativeIterator) + plength * sizeof(Value) + slength * sizeof(uint32));
cx->malloc(sizeof(NativeIterator) + plength * sizeof(Value));
if (!ni)
return NULL;
ni->props_array = ni->props_cursor = (Value *) (ni + 1);
@@ -499,20 +499,21 @@ NativeIterator::allocateValueIterator(JSContext *cx, uint32 slength, const AutoV
}
inline void
NativeIterator::init(JSObject *obj, uintN flags, const uint32 *sarray, uint32 slength, uint32 key)
NativeIterator::init(JSObject *obj, uintN flags, uint32 slength, uint32 key)
{
this->obj = obj;
this->flags = flags;
this->shapes_array = (uint32 *) this->props_end;
this->shapes_length = slength;
this->shapes_key = key;
if (slength)
memcpy(this->shapes_array, sarray, slength * sizeof(uint32));
}
static inline void
RegisterEnumerator(JSContext *cx, JSObject *iterobj, NativeIterator *ni)
{
JS_ASSERT(!(ni->flags & JSITER_ACTIVE));
ni->flags |= JSITER_ACTIVE;
/* Register non-escaping native enumerators (for-in) with the current context. */
if (ni->flags & JSITER_ENUMERATE) {
ni->next = cx->enumerators;
@@ -522,7 +523,7 @@ RegisterEnumerator(JSContext *cx, JSObject *iterobj, NativeIterator *ni)
static inline bool
VectorToKeyIterator(JSContext *cx, JSObject *obj, uintN flags, AutoIdVector &keys,
const uint32 *sarray, uint32 slength, uint32 key, Value *vp)
uint32 slength, uint32 key, Value *vp)
{
JS_ASSERT(!(flags & JSITER_FOREACH));
@@ -530,11 +531,27 @@ VectorToKeyIterator(JSContext *cx, JSObject *obj, uintN flags, AutoIdVector &key
if (!iterobj)
return false;
NativeIterator *ni = NativeIterator::allocateKeyIterator(cx, slength, keys);
if (!ni)
return NULL;
ni->init(obj, flags, sarray, slength, key);
return false;
ni->init(obj, flags, slength, key);
if (slength) {
/*
* Fill in the shape array from scratch. We can't use the array that was
* computed for the cache lookup earlier, as constructing iterobj could
* have triggered a shape-regenerating GC. Don't bother with regenerating
* the shape key; if such a GC *does* occur, we can only get hits through
* the one-slot lastNativeIterator cache.
*/
JSObject *pobj = obj;
size_t ind = 0;
do {
ni->shapes_array[ind++] = pobj->shape();
pobj = pobj->getProto();
} while (pobj);
JS_ASSERT(ind == slength);
}
iterobj->setNativeIterator(ni);
vp->setObject(*iterobj);
@@ -546,12 +563,12 @@ VectorToKeyIterator(JSContext *cx, JSObject *obj, uintN flags, AutoIdVector &key
bool
VectorToKeyIterator(JSContext *cx, JSObject *obj, uintN flags, AutoIdVector &props, Value *vp)
{
return VectorToKeyIterator(cx, obj, flags, props, NULL, 0, 0, vp);
return VectorToKeyIterator(cx, obj, flags, props, 0, 0, vp);
}
static inline bool
bool
VectorToValueIterator(JSContext *cx, JSObject *obj, uintN flags, AutoValueVector &vals,
const uint32 *sarray, uint32 slength, uint32 key, Value *vp)
Value *vp)
{
JS_ASSERT(flags & JSITER_FOREACH);
@@ -559,10 +576,10 @@ VectorToValueIterator(JSContext *cx, JSObject *obj, uintN flags, AutoValueVector
if (!iterobj)
return false;
NativeIterator *ni = NativeIterator::allocateValueIterator(cx, slength, vals);
NativeIterator *ni = NativeIterator::allocateValueIterator(cx, vals);
if (!ni)
return NULL;
ni->init(obj, flags, sarray, slength, key);
return false;
ni->init(obj, flags, 0, 0);
iterobj->setNativeIterator(ni);
vp->setObject(*iterobj);
@@ -571,12 +588,6 @@ VectorToValueIterator(JSContext *cx, JSObject *obj, uintN flags, AutoValueVector
return true;
}
bool
VectorToValueIterator(JSContext *cx, JSObject *obj, uintN flags, AutoValueVector &props, Value *vp)
{
return VectorToValueIterator(cx, obj, flags, props, NULL, 0, 0, vp);
}
bool
EnumeratedIdVectorToIterator(JSContext *cx, JSObject *obj, uintN flags, AutoIdVector &props, Value *vp)
{
@@ -613,11 +624,31 @@ GetIterator(JSContext *cx, JSObject *obj, uintN flags, Value *vp)
if (obj) {
if (keysOnly) {
/*
* Check to see if this is the same as the most recent object which
* was iterated over. We don't explicitly check for shapeless
* objects here, as they are not inserted into the cache and
* will result in a miss.
*/
JSObject *last = JS_THREAD_DATA(cx)->lastNativeIterator;
JSObject *proto = obj->getProto();
if (last) {
NativeIterator *lastni = last->getNativeIterator();
if (!(lastni->flags & JSITER_ACTIVE) &&
obj->shapeUnchecked() == lastni->shapes_array[0] &&
proto && proto->shapeUnchecked() == lastni->shapes_array[1] &&
!proto->getProto()) {
vp->setObject(*last);
RegisterEnumerator(cx, last, lastni);
return true;
}
}
/*
* The iterator object for JSITER_ENUMERATE never escapes, so we
* don't care for the proper parent/proto to be set. This also
* allows us to re-use a previous iterator object that was freed
* by JSOP_ENDITER.
* allows us to re-use a previous iterator object that is not
* currently active.
*/
JSObject *pobj = obj;
do {
@@ -639,13 +670,15 @@ GetIterator(JSContext *cx, JSObject *obj, uintN flags, Value *vp)
JSObject *iterobj = *hp;
if (iterobj) {
NativeIterator *ni = iterobj->getNativeIterator();
if (ni->shapes_key == key &&
if (!(ni->flags & JSITER_ACTIVE) &&
ni->shapes_key == key &&
ni->shapes_length == shapes.length() &&
Compare(ni->shapes_array, shapes.begin(), ni->shapes_length)) {
vp->setObject(*iterobj);
*hp = ni->next;
RegisterEnumerator(cx, iterobj, ni);
if (shapes.length() == 2)
JS_THREAD_DATA(cx)->lastNativeIterator = iterobj;
return true;
}
}
@@ -666,13 +699,29 @@ GetIterator(JSContext *cx, JSObject *obj, uintN flags, Value *vp)
AutoValueVector vals(cx);
if (JS_LIKELY(obj != NULL) && !Snapshot<ValueEnumeration>(cx, obj, flags, vals))
return false;
return VectorToValueIterator(cx, obj, flags, vals, shapes.begin(), shapes.length(), key, vp);
JS_ASSERT(shapes.empty());
if (!VectorToValueIterator(cx, obj, flags, vals, vp))
return false;
} else {
AutoIdVector keys(cx);
if (JS_LIKELY(obj != NULL) && !Snapshot<KeyEnumeration>(cx, obj, flags, keys))
return false;
if (!VectorToKeyIterator(cx, obj, flags, keys, shapes.length(), key, vp))
return false;
}
AutoIdVector keys(cx);
if (JS_LIKELY(obj != NULL) && !Snapshot<KeyEnumeration>(cx, obj, flags, keys))
return false;
return VectorToKeyIterator(cx, obj, flags, keys, shapes.begin(), shapes.length(), key, vp);
JSObject *iterobj = &vp->toObject();
/* Cache the iterator object if possible. */
if (shapes.length()) {
uint32 hash = key % NATIVE_ITER_CACHE_SIZE;
JSObject **hp = &JS_THREAD_DATA(cx)->cachedNativeIterators[hash];
*hp = iterobj;
}
if (shapes.length() == 2)
JS_THREAD_DATA(cx)->lastNativeIterator = iterobj;
return true;
}
static JSObject *
@@ -799,21 +848,18 @@ js_CloseIterator(JSContext *cx, JSObject *obj)
if (clasp == &js_IteratorClass) {
/* Remove enumerators from the active list, which is a stack. */
NativeIterator *ni = obj->getNativeIterator();
JS_ASSERT(ni->flags & JSITER_ACTIVE);
ni->flags &= ~JSITER_ACTIVE;
if (ni->flags & JSITER_ENUMERATE) {
JS_ASSERT(cx->enumerators == obj);
cx->enumerators = ni->next;
}
/* Cache the iterator object if possible. */
if (ni->shapes_length) {
uint32 hash = ni->shapes_key % NATIVE_ITER_CACHE_SIZE;
JSObject **hp = &JS_THREAD_DATA(cx)->cachedNativeIterators[hash];
ni->props_cursor = ni->props_array;
ni->next = *hp;
*hp = obj;
} else {
iterator_finalize(cx, obj);
}
/* Reset the enumerator; it may still be in the cached iterators
* for this thread, and can be reused. */
ni->props_cursor = ni->props_array;
}
#if JS_HAS_GENERATORS
else if (clasp == &js_GeneratorClass) {