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Bug 500431 - Encapsulate the property cache using C++ best practices - Part 1, just moving a few functions to a new file.

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This commit is contained in:
Jason Orendorff 2009-09-17 18:23:36 -05:00
parent 8180b3b7c3
commit 666b4c3e13
5 changed files with 795 additions and 703 deletions
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1
js/src/Makefile.in
View File

@ -147,6 +147,7 @@ CPPSRCS = \
jsopcode.cpp \
jsparse.cpp \
jsprf.cpp \
jspropcache.cpp \
jsregexp.cpp \
jsscan.cpp \
jsscope.cpp \

486
js/src/jsinterp.cpp
View File

@ -91,492 +91,6 @@
/* jsinvoke_cpp___ indicates inclusion from jsinvoke.cpp. */
#if !JS_LONE_INTERPRET ^ defined jsinvoke_cpp___
JS_REQUIRES_STACK JSPropCacheEntry *
js_FillPropertyCache(JSContext *cx, JSObject *obj,
uintN scopeIndex, uintN protoIndex, JSObject *pobj,
JSScopeProperty *sprop, JSBool adding)
{
JSPropertyCache *cache;
jsbytecode *pc;
JSScope *scope;
jsuword kshape, vshape, khash;
JSOp op;
const JSCodeSpec *cs;
jsuword vword;
ptrdiff_t pcoff;
JSAtom *atom;
JSPropCacheEntry *entry;
JS_ASSERT(!cx->runtime->gcRunning);
cache = &JS_PROPERTY_CACHE(cx);
/* FIXME bug 489098: consider enabling the property cache for eval. */
if (js_IsPropertyCacheDisabled(cx) || (cx->fp->flags & JSFRAME_EVAL)) {
PCMETER(cache->disfills++);
return JS_NO_PROP_CACHE_FILL;
}
/*
* Check for fill from js_SetPropertyHelper where the setter removed sprop
* from pobj's scope (via unwatch or delete, e.g.).
*/
scope = OBJ_SCOPE(pobj);
if (!scope->has(sprop)) {
PCMETER(cache->oddfills++);
return JS_NO_PROP_CACHE_FILL;
}
/*
* Check for overdeep scope and prototype chain. Because resolve, getter,
* and setter hooks can change the prototype chain using JS_SetPrototype
* after js_LookupPropertyWithFlags has returned the nominal protoIndex,
* we have to validate protoIndex if it is non-zero. If it is zero, then
* we know thanks to the scope->has test above, combined with the fact that
* obj == pobj, that protoIndex is invariant.
*
* The scopeIndex can't be wrong. We require JS_SetParent calls to happen
* before any running script might consult a parent-linked scope chain. If
* this requirement is not satisfied, the fill in progress will never hit,
* but vcap vs. scope shape tests ensure nothing malfunctions.
*/
JS_ASSERT_IF(scopeIndex == 0 && protoIndex == 0, obj == pobj);
if (protoIndex != 0) {
JSObject *tmp = obj;
for (uintN i = 0; i != scopeIndex; i++)
tmp = OBJ_GET_PARENT(cx, tmp);
JS_ASSERT(tmp != pobj);
protoIndex = 1;
for (;;) {
tmp = OBJ_GET_PROTO(cx, tmp);
/*
* We cannot cache properties coming from native objects behind
* non-native ones on the prototype chain. The non-natives can
* mutate in arbitrary way without changing any shapes.
*/
if (!tmp || !OBJ_IS_NATIVE(tmp)) {
PCMETER(cache->noprotos++);
return JS_NO_PROP_CACHE_FILL;
}
if (tmp == pobj)
break;
++protoIndex;
}
}
if (scopeIndex > PCVCAP_SCOPEMASK || protoIndex > PCVCAP_PROTOMASK) {
PCMETER(cache->longchains++);
return JS_NO_PROP_CACHE_FILL;
}
/*
* Optimize the cached vword based on our parameters and the current pc's
* opcode format flags.
*/
pc = cx->fp->regs->pc;
op = js_GetOpcode(cx, cx->fp->script, pc);
cs = &js_CodeSpec[op];
kshape = 0;
do {
/*
* Check for a prototype "plain old method" callee computation. What
* is a plain old method? It's a function-valued property with stub
* getter, so get of a function is idempotent.
*/
if (cs->format & JOF_CALLOP) {
jsval v;
if (sprop->isMethod()) {
/*
* A compiler-created function object, AKA a method, already
* memoized in the property tree.
*/
JS_ASSERT(scope->hasMethodBarrier());
v = sprop->methodValue();
JS_ASSERT(VALUE_IS_FUNCTION(cx, v));
JS_ASSERT(v == LOCKED_OBJ_GET_SLOT(pobj, sprop->slot));
vword = JSVAL_OBJECT_TO_PCVAL(v);
break;
}
if (SPROP_HAS_STUB_GETTER(sprop) &&
SPROP_HAS_VALID_SLOT(sprop, scope)) {
v = LOCKED_OBJ_GET_SLOT(pobj, sprop->slot);
if (VALUE_IS_FUNCTION(cx, v)) {
/*
* Great, we have a function-valued prototype property
* where the getter is JS_PropertyStub. The type id in
* pobj's scope does not evolve with changes to property
* values, however.
*
* So here, on first cache fill for this method, we brand
* the scope with a new shape and set the JSScope::BRANDED
* flag. Once this flag is set, any property assignment
* that changes the value from or to a different function
* object will result in shape being regenerated.
*/
if (!scope->branded()) {
PCMETER(cache->brandfills++);
#ifdef DEBUG_notme
fprintf(stderr,
"branding %p (%s) for funobj %p (%s), shape %lu\n",
pobj, pobj->getClass()->name,
JSVAL_TO_OBJECT(v),
JS_GetFunctionName(GET_FUNCTION_PRIVATE(cx, JSVAL_TO_OBJECT(v))),
OBJ_SHAPE(obj));
#endif
scope->brandingShapeChange(cx, sprop->slot, v);
if (js_IsPropertyCacheDisabled(cx)) /* check for rt->shapeGen overflow */
return JS_NO_PROP_CACHE_FILL;
scope->setBranded();
}
vword = JSVAL_OBJECT_TO_PCVAL(v);
break;
}
}
}
/* If getting a value via a stub getter, we can cache the slot. */
if (!(cs->format & (JOF_SET | JOF_INCDEC | JOF_FOR)) &&
SPROP_HAS_STUB_GETTER(sprop) &&
SPROP_HAS_VALID_SLOT(sprop, scope)) {
/* Great, let's cache sprop's slot and use it on cache hit. */
vword = SLOT_TO_PCVAL(sprop->slot);
} else {
/* Best we can do is to cache sprop (still a nice speedup). */
vword = SPROP_TO_PCVAL(sprop);
if (adding &&
sprop == scope->lastProp &&
scope->shape == sprop->shape) {
/*
* Our caller added a new property. We also know that a setter
* that js_NativeSet could have run has not mutated the scope,
* so the added property is still the last one added, and the
* scope is not branded.
*
* We want to cache under scope's shape before the property
* addition to bias for the case when the mutator opcode
* always adds the same property. This allows us to optimize
* periodic execution of object initializers or other explicit
* initialization sequences such as
*
* obj = {}; obj.x = 1; obj.y = 2;
*
* We assume that on average the win from this optimization is
* greater than the cost of an extra mismatch per loop owing to
* the bias for the following case:
*
* obj = {}; ... for (...) { ... obj.x = ... }
*
* On the first iteration of such a for loop, JSOP_SETPROP
* fills the cache with the shape of the newly created object
* obj, not the shape of obj after obj.x has been assigned.
* That mismatches obj's shape on the second iteration. Note
* that on the third and subsequent iterations the cache will
* be hit because the shape is no longer updated.
*/
JS_ASSERT(scope->owned());
if (sprop->parent) {
kshape = sprop->parent->shape;
} else {
/*
* If obj had its own empty scope before, with a unique
* shape, that is lost. Here we only attempt to find a
* matching empty scope. In unusual cases involving
* __proto__ assignment we may not find one.
*/
JSObject *proto = STOBJ_GET_PROTO(obj);
if (!proto || !OBJ_IS_NATIVE(proto))
return JS_NO_PROP_CACHE_FILL;
JSScope *protoscope = OBJ_SCOPE(proto);
if (!protoscope->emptyScope ||
!js_ObjectIsSimilarToProto(cx, obj, obj->map->ops, OBJ_GET_CLASS(cx, obj),
proto)) {
return JS_NO_PROP_CACHE_FILL;
}
kshape = protoscope->emptyScope->shape;
}
/*
* When adding we predict no prototype object will later gain a
* readonly property or setter.
*/
vshape = cx->runtime->protoHazardShape;
}
}
} while (0);
if (kshape == 0) {
kshape = OBJ_SHAPE(obj);
vshape = scope->shape;
}
khash = PROPERTY_CACHE_HASH_PC(pc, kshape);
if (obj == pobj) {
JS_ASSERT(scopeIndex == 0 && protoIndex == 0);
} else {
if (op == JSOP_LENGTH) {
atom = cx->runtime->atomState.lengthAtom;
} else {
pcoff = (JOF_TYPE(cs->format) == JOF_SLOTATOM) ? SLOTNO_LEN : 0;
GET_ATOM_FROM_BYTECODE(cx->fp->script, pc, pcoff, atom);
}
#ifdef DEBUG
if (scopeIndex == 0) {
JS_ASSERT(protoIndex != 0);
JS_ASSERT((protoIndex == 1) == (OBJ_GET_PROTO(cx, obj) == pobj));
}
#endif
if (scopeIndex != 0 || protoIndex != 1) {
khash = PROPERTY_CACHE_HASH_ATOM(atom, obj);
PCMETER(if (PCVCAP_TAG(cache->table[khash].vcap) <= 1)
cache->pcrecycles++);
pc = (jsbytecode *) atom;
kshape = (jsuword) obj;
/*
* Make sure that a later shadowing assignment will enter
* PurgeProtoChain and invalidate this entry, bug 479198.
*
* This is thread-safe even though obj is not locked. Only the
* DELEGATE bit of obj->classword can change at runtime, given that
* obj is native; and the bit is only set, never cleared. And on
* platforms where another CPU can fail to see this write, it's OK
* because the property cache and JIT cache are thread-local.
*/
obj->setDelegate();
}
}
entry = &cache->table[khash];
PCMETER(PCVAL_IS_NULL(entry->vword) || cache->recycles++);
entry->kpc = pc;
entry->kshape = kshape;
entry->vcap = PCVCAP_MAKE(vshape, scopeIndex, protoIndex);
entry->vword = vword;
cache->empty = JS_FALSE;
PCMETER(cache->fills++);
/*
* The modfills counter is not exact. It increases if a getter or setter
* recurse into the interpreter.
*/
PCMETER(entry == cache->pctestentry || cache->modfills++);
PCMETER(cache->pctestentry = NULL);
return entry;
}
JS_REQUIRES_STACK JSAtom *
js_FullTestPropertyCache(JSContext *cx, jsbytecode *pc,
JSObject **objp, JSObject **pobjp,
JSPropCacheEntry **entryp)
{
JSOp op;
const JSCodeSpec *cs;
ptrdiff_t pcoff;
JSAtom *atom;
JSObject *obj, *pobj, *tmp;
JSPropCacheEntry *entry;
uint32 vcap;
JS_ASSERT(uintN((cx->fp->imacpc ? cx->fp->imacpc : pc) - cx->fp->script->code)
< cx->fp->script->length);
op = js_GetOpcode(cx, cx->fp->script, pc);
cs = &js_CodeSpec[op];
if (op == JSOP_LENGTH) {
atom = cx->runtime->atomState.lengthAtom;
} else {
pcoff = (JOF_TYPE(cs->format) == JOF_SLOTATOM) ? SLOTNO_LEN : 0;
GET_ATOM_FROM_BYTECODE(cx->fp->script, pc, pcoff, atom);
}
obj = *objp;
JS_ASSERT(OBJ_IS_NATIVE(obj));
entry = &JS_PROPERTY_CACHE(cx).table[PROPERTY_CACHE_HASH_ATOM(atom, obj)];
*entryp = entry;
vcap = entry->vcap;
if (entry->kpc != (jsbytecode *) atom) {
PCMETER(JS_PROPERTY_CACHE(cx).idmisses++);
#ifdef DEBUG_notme
entry = &JS_PROPERTY_CACHE(cx).table[PROPERTY_CACHE_HASH_PC(pc, OBJ_SHAPE(obj))];
fprintf(stderr,
"id miss for %s from %s:%u"
" (pc %u, kpc %u, kshape %u, shape %u)\n",
js_AtomToPrintableString(cx, atom),
cx->fp->script->filename,
js_PCToLineNumber(cx, cx->fp->script, pc),
pc - cx->fp->script->code,
entry->kpc - cx->fp->script->code,
entry->kshape,
OBJ_SHAPE(obj));
js_Disassemble1(cx, cx->fp->script, pc,
pc - cx->fp->script->code,
JS_FALSE, stderr);
#endif
return atom;
}
if (entry->kshape != (jsuword) obj) {
PCMETER(JS_PROPERTY_CACHE(cx).komisses++);
return atom;
}
pobj = obj;
if (JOF_MODE(cs->format) == JOF_NAME) {
while (vcap & (PCVCAP_SCOPEMASK << PCVCAP_PROTOBITS)) {
tmp = OBJ_GET_PARENT(cx, pobj);
if (!tmp || !OBJ_IS_NATIVE(tmp))
break;
pobj = tmp;
vcap -= PCVCAP_PROTOSIZE;
}
*objp = pobj;
}
while (vcap & PCVCAP_PROTOMASK) {
tmp = OBJ_GET_PROTO(cx, pobj);
if (!tmp || !OBJ_IS_NATIVE(tmp))
break;
pobj = tmp;
--vcap;
}
if (JS_LOCK_OBJ_IF_SHAPE(cx, pobj, PCVCAP_SHAPE(vcap))) {
#ifdef DEBUG
jsid id = ATOM_TO_JSID(atom);
id = js_CheckForStringIndex(id);
JS_ASSERT(OBJ_SCOPE(pobj)->lookup(id));
JS_ASSERT_IF(OBJ_SCOPE(pobj)->object, OBJ_SCOPE(pobj)->object == pobj);
#endif
*pobjp = pobj;
return NULL;
}
PCMETER(JS_PROPERTY_CACHE(cx).vcmisses++);
return atom;
}
#ifdef DEBUG
#define ASSERT_CACHE_IS_EMPTY(cache) \
JS_BEGIN_MACRO \
JSPropertyCache *cache_ = (cache); \
uintN i_; \
JS_ASSERT(cache_->empty); \
for (i_ = 0; i_ < PROPERTY_CACHE_SIZE; i_++) { \
JS_ASSERT(!cache_->table[i_].kpc); \
JS_ASSERT(!cache_->table[i_].kshape); \
JS_ASSERT(!cache_->table[i_].vcap); \
JS_ASSERT(!cache_->table[i_].vword); \
} \
JS_END_MACRO
#else
#define ASSERT_CACHE_IS_EMPTY(cache) ((void)0)
#endif
JS_STATIC_ASSERT(PCVAL_NULL == 0);
void
js_PurgePropertyCache(JSContext *cx, JSPropertyCache *cache)
{
if (cache->empty) {
ASSERT_CACHE_IS_EMPTY(cache);
return;
}
memset(cache->table, 0, sizeof cache->table);
cache->empty = JS_TRUE;
#ifdef JS_PROPERTY_CACHE_METERING
{ static FILE *fp;
if (!fp)
fp = fopen("/tmp/propcache.stats", "w");
if (fp) {
fputs("Property cache stats for ", fp);
#ifdef JS_THREADSAFE
fprintf(fp, "thread %lu, ", (unsigned long) cx->thread->id);
#endif
fprintf(fp, "GC %u\n", cx->runtime->gcNumber);
# define P(mem) fprintf(fp, "%11s %10lu\n", #mem, (unsigned long)cache->mem)
P(fills);
P(nofills);
P(rofills);
P(disfills);
P(oddfills);
P(modfills);
P(brandfills);
P(noprotos);
P(longchains);
P(recycles);
P(pcrecycles);
P(tests);
P(pchits);
P(protopchits);
P(initests);
P(inipchits);
P(inipcmisses);
P(settests);
P(addpchits);
P(setpchits);
P(setpcmisses);
P(slotchanges);
P(setmisses);
P(idmisses);
P(komisses);
P(vcmisses);
P(misses);
P(flushes);
P(pcpurges);
# undef P
fprintf(fp, "hit rates: pc %g%% (proto %g%%), set %g%%, ini %g%%, full %g%%\n",
(100. * cache->pchits) / cache->tests,
(100. * cache->protopchits) / cache->tests,
(100. * (cache->addpchits + cache->setpchits))
/ cache->settests,
(100. * cache->inipchits) / cache->initests,
(100. * (cache->tests - cache->misses)) / cache->tests);
fflush(fp);
}
}
#endif
PCMETER(cache->flushes++);
}
void
js_PurgePropertyCacheForScript(JSContext *cx, JSScript *script)
{
JSPropertyCache *cache;
JSPropCacheEntry *entry;
cache = &JS_PROPERTY_CACHE(cx);
for (entry = cache->table; entry < cache->table + PROPERTY_CACHE_SIZE;
entry++) {
if (JS_UPTRDIFF(entry->kpc, script->code) < script->length) {
entry->kpc = NULL;
entry->kshape = 0;
#ifdef DEBUG
entry->vcap = entry->vword = 0;
#endif
}
}
}
/*
* Check if the current arena has enough space to fit nslots after sp and, if
* so, reserve the necessary space.

218
js/src/jsinterp.h
View File

@ -47,6 +47,7 @@
#include "jspubtd.h"
#include "jsfun.h"
#include "jsopcode.h"
#include "jspropcache.h"
#include "jsscript.h"
JS_BEGIN_EXTERN_C
@ -204,223 +205,6 @@ typedef struct JSInlineFrame {
#define JSFRAME_SPECIAL (JSFRAME_DEBUGGER | JSFRAME_EVAL)
/*
* Property cache with structurally typed capabilities for invalidation, for
* polymorphic callsite method/get/set speedups. For details, see
* <https://developer.mozilla.org/en/SpiderMonkey/Internals/Property_cache>.
*/
#define PROPERTY_CACHE_LOG2 12
#define PROPERTY_CACHE_SIZE JS_BIT(PROPERTY_CACHE_LOG2)
#define PROPERTY_CACHE_MASK JS_BITMASK(PROPERTY_CACHE_LOG2)
/*
* Add kshape rather than xor it to avoid collisions between nearby bytecode
* that are evolving an object by setting successive properties, incrementing
* the object's scope->shape on each set.
*/
#define PROPERTY_CACHE_HASH(pc,kshape) \
(((((jsuword)(pc) >> PROPERTY_CACHE_LOG2) ^ (jsuword)(pc)) + (kshape)) & \
PROPERTY_CACHE_MASK)
#define PROPERTY_CACHE_HASH_PC(pc,kshape) \
PROPERTY_CACHE_HASH(pc, kshape)
#define PROPERTY_CACHE_HASH_ATOM(atom,obj) \
PROPERTY_CACHE_HASH((jsuword)(atom) >> 2, OBJ_SHAPE(obj))
/*
* Property cache value capability macros.
*/
#define PCVCAP_PROTOBITS 4
#define PCVCAP_PROTOSIZE JS_BIT(PCVCAP_PROTOBITS)
#define PCVCAP_PROTOMASK JS_BITMASK(PCVCAP_PROTOBITS)
#define PCVCAP_SCOPEBITS 4
#define PCVCAP_SCOPESIZE JS_BIT(PCVCAP_SCOPEBITS)
#define PCVCAP_SCOPEMASK JS_BITMASK(PCVCAP_SCOPEBITS)
#define PCVCAP_TAGBITS (PCVCAP_PROTOBITS + PCVCAP_SCOPEBITS)
#define PCVCAP_TAGMASK JS_BITMASK(PCVCAP_TAGBITS)
#define PCVCAP_TAG(t) ((t) & PCVCAP_TAGMASK)
#define PCVCAP_MAKE(t,s,p) ((uint32(t) << PCVCAP_TAGBITS) | \
((s) << PCVCAP_PROTOBITS) | \
(p))
#define PCVCAP_SHAPE(t) ((t) >> PCVCAP_TAGBITS)
#define SHAPE_OVERFLOW_BIT JS_BIT(32 - PCVCAP_TAGBITS)
struct JSPropCacheEntry {
jsbytecode *kpc; /* pc if vcap tag is <= 1, else atom */
jsuword kshape; /* key shape if pc, else obj for atom */
jsuword vcap; /* value capability, see above */
jsuword vword; /* value word, see PCVAL_* below */
bool adding() const {
return PCVCAP_TAG(vcap) == 0 && kshape != PCVCAP_SHAPE(vcap);
}
bool directHit() const {
return PCVCAP_TAG(vcap) == 0 && kshape == PCVCAP_SHAPE(vcap);
}
};
/*
* Special value for functions returning JSPropCacheEntry * to distinguish
* between failure and no no-cache-fill cases.
*/
#define JS_NO_PROP_CACHE_FILL ((JSPropCacheEntry *) NULL + 1)
#if defined DEBUG_brendan || defined DEBUG_brendaneich
#define JS_PROPERTY_CACHE_METERING 1
#endif
typedef struct JSPropertyCache {
JSPropCacheEntry table[PROPERTY_CACHE_SIZE];
JSBool empty;
#ifdef JS_PROPERTY_CACHE_METERING
JSPropCacheEntry *pctestentry; /* entry of the last PC-based test */
uint32 fills; /* number of cache entry fills */
uint32 nofills; /* couldn't fill (e.g. default get) */
uint32 rofills; /* set on read-only prop can't fill */
uint32 disfills; /* fill attempts on disabled cache */
uint32 oddfills; /* fill attempt after setter deleted */
uint32 modfills; /* fill that rehashed to a new entry */
uint32 brandfills; /* scope brandings to type structural
method fills */
uint32 noprotos; /* resolve-returned non-proto pobj */
uint32 longchains; /* overlong scope and/or proto chain */
uint32 recycles; /* cache entries recycled by fills */
uint32 pcrecycles; /* pc-keyed entries recycled by atom-
keyed fills */
uint32 tests; /* cache probes */
uint32 pchits; /* fast-path polymorphic op hits */
uint32 protopchits; /* pchits hitting immediate prototype */
uint32 initests; /* cache probes from JSOP_INITPROP */
uint32 inipchits; /* init'ing next property pchit case */
uint32 inipcmisses; /* init'ing next property pc misses */
uint32 settests; /* cache probes from JOF_SET opcodes */
uint32 addpchits; /* adding next property pchit case */
uint32 setpchits; /* setting existing property pchit */
uint32 setpcmisses; /* setting/adding property pc misses */
uint32 slotchanges; /* clasp->reserveSlots result variance-
induced slot changes */
uint32 setmisses; /* JSOP_SET{NAME,PROP} total misses */
uint32 idmisses; /* slow-path key id == atom misses */
uint32 komisses; /* slow-path key object misses */
uint32 vcmisses; /* value capability misses */
uint32 misses; /* cache misses */
uint32 flushes; /* cache flushes */
uint32 pcpurges; /* shadowing purges on proto chain */
# define PCMETER(x) x
#else
# define PCMETER(x) ((void)0)
#endif
} JSPropertyCache;
/*
* Property cache value tagging/untagging macros.
*/
#define PCVAL_OBJECT 0
#define PCVAL_SLOT 1
#define PCVAL_SPROP 2
#define PCVAL_TAGBITS 2
#define PCVAL_TAGMASK JS_BITMASK(PCVAL_TAGBITS)
#define PCVAL_TAG(v) ((v) & PCVAL_TAGMASK)
#define PCVAL_CLRTAG(v) ((v) & ~(jsuword)PCVAL_TAGMASK)
#define PCVAL_SETTAG(v,t) ((jsuword)(v) | (t))
#define PCVAL_NULL 0
#define PCVAL_IS_NULL(v) ((v) == PCVAL_NULL)
#define PCVAL_IS_OBJECT(v) (PCVAL_TAG(v) == PCVAL_OBJECT)
#define PCVAL_TO_OBJECT(v) ((JSObject *) (v))
#define OBJECT_TO_PCVAL(obj) ((jsuword) (obj))
#define PCVAL_OBJECT_TO_JSVAL(v) OBJECT_TO_JSVAL(PCVAL_TO_OBJECT(v))
#define JSVAL_OBJECT_TO_PCVAL(v) OBJECT_TO_PCVAL(JSVAL_TO_OBJECT(v))
#define PCVAL_IS_SLOT(v) ((v) & PCVAL_SLOT)
#define PCVAL_TO_SLOT(v) ((jsuint)(v) >> 1)
#define SLOT_TO_PCVAL(i) (((jsuword)(i) << 1) | PCVAL_SLOT)
#define PCVAL_IS_SPROP(v) (PCVAL_TAG(v) == PCVAL_SPROP)
#define PCVAL_TO_SPROP(v) ((JSScopeProperty *) PCVAL_CLRTAG(v))
#define SPROP_TO_PCVAL(sprop) PCVAL_SETTAG(sprop, PCVAL_SPROP)
/*
* Fill property cache entry for key cx->fp->pc, optimized value word computed
* from obj and sprop, and entry capability forged from 24-bit OBJ_SHAPE(obj),
* 4-bit scopeIndex, and 4-bit protoIndex.
*
* Return the filled cache entry or JS_NO_PROP_CACHE_FILL if caching was not
* possible.
*/
extern JS_REQUIRES_STACK JSPropCacheEntry *
js_FillPropertyCache(JSContext *cx, JSObject *obj,
uintN scopeIndex, uintN protoIndex, JSObject *pobj,
JSScopeProperty *sprop, JSBool adding);
/*
* Property cache lookup macros. PROPERTY_CACHE_TEST is designed to inline the
* fast path in js_Interpret, so it makes "just-so" restrictions on parameters,
* e.g. pobj and obj should not be the same variable, since for JOF_PROP-mode
* opcodes, obj must not be changed because of a cache miss.
*
* On return from PROPERTY_CACHE_TEST, if atom is null then obj points to the
* scope chain element in which the property was found, pobj is locked, and
* entry is valid. If atom is non-null then no object is locked but entry is
* still set correctly for use, e.g., by js_FillPropertyCache and atom should
* be used as the id to find.
*
* We must lock pobj on a hit in order to close races with threads that might
* be deleting a property from its scope, or otherwise invalidating property
* caches (on all threads) by re-generating scope->shape.
*/
#define PROPERTY_CACHE_TEST(cx, pc, obj, pobj, entry, atom) \
do { \
JSPropertyCache *cache_ = &JS_PROPERTY_CACHE(cx); \
uint32 kshape_ = (JS_ASSERT(OBJ_IS_NATIVE(obj)), OBJ_SHAPE(obj)); \
entry = &cache_->table[PROPERTY_CACHE_HASH_PC(pc, kshape_)]; \
PCMETER(cache_->pctestentry = entry); \
PCMETER(cache_->tests++); \
JS_ASSERT(&obj != &pobj); \
if (entry->kpc == pc && entry->kshape == kshape_) { \
JSObject *tmp_; \
pobj = obj; \
JS_ASSERT(PCVCAP_TAG(entry->vcap) <= 1); \
if (PCVCAP_TAG(entry->vcap) == 1 && \
(tmp_ = OBJ_GET_PROTO(cx, pobj)) != NULL) { \
pobj = tmp_; \
} \
\
if (JS_LOCK_OBJ_IF_SHAPE(cx, pobj, PCVCAP_SHAPE(entry->vcap))) { \
PCMETER(cache_->pchits++); \
PCMETER(!PCVCAP_TAG(entry->vcap) || cache_->protopchits++); \
atom = NULL; \
break; \
} \
} \
atom = js_FullTestPropertyCache(cx, pc, &obj, &pobj, &entry); \
if (atom) \
PCMETER(cache_->misses++); \
} while (0)
extern JS_REQUIRES_STACK JSAtom *
js_FullTestPropertyCache(JSContext *cx, jsbytecode *pc,
JSObject **objp, JSObject **pobjp,
JSPropCacheEntry **entryp);
/* The property cache does not need a destructor. */
#define js_FinishPropertyCache(cache) ((void) 0)
extern void
js_PurgePropertyCache(JSContext *cx, JSPropertyCache *cache);
extern void
js_PurgePropertyCacheForScript(JSContext *cx, JSScript *script);
/*
* Interpreter stack arena-pool alloc and free functions.
*/

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sw=4 et tw=79:
*
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla Communicator client code, released
* March 31, 1998.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include <string.h>
#include "jsapi.h"
#include "jscntxt.h"
#include "jsinterp.h"
#include "jsobj.h"
#include "jsscope.h"
JS_REQUIRES_STACK JSPropCacheEntry *
js_FillPropertyCache(JSContext *cx, JSObject *obj,
uintN scopeIndex, uintN protoIndex, JSObject *pobj,
JSScopeProperty *sprop, JSBool adding)
{
JSPropertyCache *cache;
jsbytecode *pc;
JSScope *scope;
jsuword kshape, vshape, khash;
JSOp op;
const JSCodeSpec *cs;
jsuword vword;
ptrdiff_t pcoff;
JSAtom *atom;
JSPropCacheEntry *entry;
JS_ASSERT(!cx->runtime->gcRunning);
cache = &JS_PROPERTY_CACHE(cx);
/* FIXME bug 489098: consider enabling the property cache for eval. */
if (js_IsPropertyCacheDisabled(cx) || (cx->fp->flags & JSFRAME_EVAL)) {
PCMETER(cache->disfills++);
return JS_NO_PROP_CACHE_FILL;
}
/*
* Check for fill from js_SetPropertyHelper where the setter removed sprop
* from pobj's scope (via unwatch or delete, e.g.).
*/
scope = OBJ_SCOPE(pobj);
if (!scope->has(sprop)) {
PCMETER(cache->oddfills++);
return JS_NO_PROP_CACHE_FILL;
}
/*
* Check for overdeep scope and prototype chain. Because resolve, getter,
* and setter hooks can change the prototype chain using JS_SetPrototype
* after js_LookupPropertyWithFlags has returned the nominal protoIndex,
* we have to validate protoIndex if it is non-zero. If it is zero, then
* we know thanks to the scope->has test above, combined with the fact that
* obj == pobj, that protoIndex is invariant.
*
* The scopeIndex can't be wrong. We require JS_SetParent calls to happen
* before any running script might consult a parent-linked scope chain. If
* this requirement is not satisfied, the fill in progress will never hit,
* but vcap vs. scope shape tests ensure nothing malfunctions.
*/
JS_ASSERT_IF(scopeIndex == 0 && protoIndex == 0, obj == pobj);
if (protoIndex != 0) {
JSObject *tmp = obj;
for (uintN i = 0; i != scopeIndex; i++)
tmp = OBJ_GET_PARENT(cx, tmp);
JS_ASSERT(tmp != pobj);
protoIndex = 1;
for (;;) {
tmp = OBJ_GET_PROTO(cx, tmp);
/*
* We cannot cache properties coming from native objects behind
* non-native ones on the prototype chain. The non-natives can
* mutate in arbitrary way without changing any shapes.
*/
if (!tmp || !OBJ_IS_NATIVE(tmp)) {
PCMETER(cache->noprotos++);
return JS_NO_PROP_CACHE_FILL;
}
if (tmp == pobj)
break;
++protoIndex;
}
}
if (scopeIndex > PCVCAP_SCOPEMASK || protoIndex > PCVCAP_PROTOMASK) {
PCMETER(cache->longchains++);
return JS_NO_PROP_CACHE_FILL;
}
/*
* Optimize the cached vword based on our parameters and the current pc's
* opcode format flags.
*/
pc = cx->fp->regs->pc;
op = js_GetOpcode(cx, cx->fp->script, pc);
cs = &js_CodeSpec[op];
kshape = 0;
do {
/*
* Check for a prototype "plain old method" callee computation. What
* is a plain old method? It's a function-valued property with stub
* getter, so get of a function is idempotent.
*/
if (cs->format & JOF_CALLOP) {
jsval v;
if (sprop->isMethod()) {
/*
* A compiler-created function object, AKA a method, already
* memoized in the property tree.
*/
JS_ASSERT(scope->hasMethodBarrier());
v = sprop->methodValue();
JS_ASSERT(VALUE_IS_FUNCTION(cx, v));
JS_ASSERT(v == LOCKED_OBJ_GET_SLOT(pobj, sprop->slot));
vword = JSVAL_OBJECT_TO_PCVAL(v);
break;
}
if (SPROP_HAS_STUB_GETTER(sprop) &&
SPROP_HAS_VALID_SLOT(sprop, scope)) {
v = LOCKED_OBJ_GET_SLOT(pobj, sprop->slot);
if (VALUE_IS_FUNCTION(cx, v)) {
/*
* Great, we have a function-valued prototype property
* where the getter is JS_PropertyStub. The type id in
* pobj's scope does not evolve with changes to property
* values, however.
*
* So here, on first cache fill for this method, we brand
* the scope with a new shape and set the JSScope::BRANDED
* flag. Once this flag is set, any property assignment
* that changes the value from or to a different function
* object will result in shape being regenerated.
*/
if (!scope->branded()) {
PCMETER(cache->brandfills++);
#ifdef DEBUG_notme
fprintf(stderr,
"branding %p (%s) for funobj %p (%s), shape %lu\n",
pobj, pobj->getClass()->name,
JSVAL_TO_OBJECT(v),
JS_GetFunctionName(GET_FUNCTION_PRIVATE(cx, JSVAL_TO_OBJECT(v))),
OBJ_SHAPE(obj));
#endif
scope->brandingShapeChange(cx, sprop->slot, v);
if (js_IsPropertyCacheDisabled(cx)) /* check for rt->shapeGen overflow */
return JS_NO_PROP_CACHE_FILL;
scope->setBranded();
}
vword = JSVAL_OBJECT_TO_PCVAL(v);
break;
}
}
}
/* If getting a value via a stub getter, we can cache the slot. */
if (!(cs->format & (JOF_SET | JOF_INCDEC | JOF_FOR)) &&
SPROP_HAS_STUB_GETTER(sprop) &&
SPROP_HAS_VALID_SLOT(sprop, scope)) {
/* Great, let's cache sprop's slot and use it on cache hit. */
vword = SLOT_TO_PCVAL(sprop->slot);
} else {
/* Best we can do is to cache sprop (still a nice speedup). */
vword = SPROP_TO_PCVAL(sprop);
if (adding &&
sprop == scope->lastProp &&
scope->shape == sprop->shape) {
/*
* Our caller added a new property. We also know that a setter
* that js_NativeSet could have run has not mutated the scope,
* so the added property is still the last one added, and the
* scope is not branded.
*
* We want to cache under scope's shape before the property
* addition to bias for the case when the mutator opcode
* always adds the same property. This allows us to optimize
* periodic execution of object initializers or other explicit
* initialization sequences such as
*
* obj = {}; obj.x = 1; obj.y = 2;
*
* We assume that on average the win from this optimization is
* greater than the cost of an extra mismatch per loop owing to
* the bias for the following case:
*
* obj = {}; ... for (...) { ... obj.x = ... }
*
* On the first iteration of such a for loop, JSOP_SETPROP
* fills the cache with the shape of the newly created object
* obj, not the shape of obj after obj.x has been assigned.
* That mismatches obj's shape on the second iteration. Note
* that on the third and subsequent iterations the cache will
* be hit because the shape is no longer updated.
*/
JS_ASSERT(scope->owned());
if (sprop->parent) {
kshape = sprop->parent->shape;
} else {
/*
* If obj had its own empty scope before, with a unique
* shape, that is lost. Here we only attempt to find a
* matching empty scope. In unusual cases involving
* __proto__ assignment we may not find one.
*/
JSObject *proto = STOBJ_GET_PROTO(obj);
if (!proto || !OBJ_IS_NATIVE(proto))
return JS_NO_PROP_CACHE_FILL;
JSScope *protoscope = OBJ_SCOPE(proto);
if (!protoscope->emptyScope ||
!js_ObjectIsSimilarToProto(cx, obj, obj->map->ops, OBJ_GET_CLASS(cx, obj),
proto)) {
return JS_NO_PROP_CACHE_FILL;
}
kshape = protoscope->emptyScope->shape;
}
/*
* When adding we predict no prototype object will later gain a
* readonly property or setter.
*/
vshape = cx->runtime->protoHazardShape;
}
}
} while (0);
if (kshape == 0) {
kshape = OBJ_SHAPE(obj);
vshape = scope->shape;
}
khash = PROPERTY_CACHE_HASH_PC(pc, kshape);
if (obj == pobj) {
JS_ASSERT(scopeIndex == 0 && protoIndex == 0);
} else {
if (op == JSOP_LENGTH) {
atom = cx->runtime->atomState.lengthAtom;
} else {
pcoff = (JOF_TYPE(cs->format) == JOF_SLOTATOM) ? SLOTNO_LEN : 0;
GET_ATOM_FROM_BYTECODE(cx->fp->script, pc, pcoff, atom);
}
#ifdef DEBUG
if (scopeIndex == 0) {
JS_ASSERT(protoIndex != 0);
JS_ASSERT((protoIndex == 1) == (OBJ_GET_PROTO(cx, obj) == pobj));
}
#endif
if (scopeIndex != 0 || protoIndex != 1) {
khash = PROPERTY_CACHE_HASH_ATOM(atom, obj);
PCMETER(if (PCVCAP_TAG(cache->table[khash].vcap) <= 1)
cache->pcrecycles++);
pc = (jsbytecode *) atom;
kshape = (jsuword) obj;
/*
* Make sure that a later shadowing assignment will enter
* PurgeProtoChain and invalidate this entry, bug 479198.
*
* This is thread-safe even though obj is not locked. Only the
* DELEGATE bit of obj->classword can change at runtime, given that
* obj is native; and the bit is only set, never cleared. And on
* platforms where another CPU can fail to see this write, it's OK
* because the property cache and JIT cache are thread-local.
*/
obj->setDelegate();
}
}
entry = &cache->table[khash];
PCMETER(PCVAL_IS_NULL(entry->vword) || cache->recycles++);
entry->kpc = pc;
entry->kshape = kshape;
entry->vcap = PCVCAP_MAKE(vshape, scopeIndex, protoIndex);
entry->vword = vword;
cache->empty = JS_FALSE;
PCMETER(cache->fills++);
/*
* The modfills counter is not exact. It increases if a getter or setter
* recurse into the interpreter.
*/
PCMETER(entry == cache->pctestentry || cache->modfills++);
PCMETER(cache->pctestentry = NULL);
return entry;
}
JS_REQUIRES_STACK JSAtom *
js_FullTestPropertyCache(JSContext *cx, jsbytecode *pc,
JSObject **objp, JSObject **pobjp,
JSPropCacheEntry **entryp)
{
JSOp op;
const JSCodeSpec *cs;
ptrdiff_t pcoff;
JSAtom *atom;
JSObject *obj, *pobj, *tmp;
JSPropCacheEntry *entry;
uint32 vcap;
JS_ASSERT(uintN((cx->fp->imacpc ? cx->fp->imacpc : pc) - cx->fp->script->code)
< cx->fp->script->length);
op = js_GetOpcode(cx, cx->fp->script, pc);
cs = &js_CodeSpec[op];
if (op == JSOP_LENGTH) {
atom = cx->runtime->atomState.lengthAtom;
} else {
pcoff = (JOF_TYPE(cs->format) == JOF_SLOTATOM) ? SLOTNO_LEN : 0;
GET_ATOM_FROM_BYTECODE(cx->fp->script, pc, pcoff, atom);
}
obj = *objp;
JS_ASSERT(OBJ_IS_NATIVE(obj));
entry = &JS_PROPERTY_CACHE(cx).table[PROPERTY_CACHE_HASH_ATOM(atom, obj)];
*entryp = entry;
vcap = entry->vcap;
if (entry->kpc != (jsbytecode *) atom) {
PCMETER(JS_PROPERTY_CACHE(cx).idmisses++);
#ifdef DEBUG_notme
entry = &JS_PROPERTY_CACHE(cx).table[PROPERTY_CACHE_HASH_PC(pc, OBJ_SHAPE(obj))];
fprintf(stderr,
"id miss for %s from %s:%u"
" (pc %u, kpc %u, kshape %u, shape %u)\n",
js_AtomToPrintableString(cx, atom),
cx->fp->script->filename,
js_PCToLineNumber(cx, cx->fp->script, pc),
pc - cx->fp->script->code,
entry->kpc - cx->fp->script->code,
entry->kshape,
OBJ_SHAPE(obj));
js_Disassemble1(cx, cx->fp->script, pc,
pc - cx->fp->script->code,
JS_FALSE, stderr);
#endif
return atom;
}
if (entry->kshape != (jsuword) obj) {
PCMETER(JS_PROPERTY_CACHE(cx).komisses++);
return atom;
}
pobj = obj;
if (JOF_MODE(cs->format) == JOF_NAME) {
while (vcap & (PCVCAP_SCOPEMASK << PCVCAP_PROTOBITS)) {
tmp = OBJ_GET_PARENT(cx, pobj);
if (!tmp || !OBJ_IS_NATIVE(tmp))
break;
pobj = tmp;
vcap -= PCVCAP_PROTOSIZE;
}
*objp = pobj;
}
while (vcap & PCVCAP_PROTOMASK) {
tmp = OBJ_GET_PROTO(cx, pobj);
if (!tmp || !OBJ_IS_NATIVE(tmp))
break;
pobj = tmp;
--vcap;
}
if (JS_LOCK_OBJ_IF_SHAPE(cx, pobj, PCVCAP_SHAPE(vcap))) {
#ifdef DEBUG
jsid id = ATOM_TO_JSID(atom);
id = js_CheckForStringIndex(id);
JS_ASSERT(OBJ_SCOPE(pobj)->lookup(id));
JS_ASSERT_IF(OBJ_SCOPE(pobj)->object, OBJ_SCOPE(pobj)->object == pobj);
#endif
*pobjp = pobj;
return NULL;
}
PCMETER(JS_PROPERTY_CACHE(cx).vcmisses++);
return atom;
}
#ifdef DEBUG
#define ASSERT_CACHE_IS_EMPTY(cache) \
JS_BEGIN_MACRO \
JSPropertyCache *cache_ = (cache); \
uintN i_; \
JS_ASSERT(cache_->empty); \
for (i_ = 0; i_ < PROPERTY_CACHE_SIZE; i_++) { \
JS_ASSERT(!cache_->table[i_].kpc); \
JS_ASSERT(!cache_->table[i_].kshape); \
JS_ASSERT(!cache_->table[i_].vcap); \
JS_ASSERT(!cache_->table[i_].vword); \
} \
JS_END_MACRO
#else
#define ASSERT_CACHE_IS_EMPTY(cache) ((void)0)
#endif
JS_STATIC_ASSERT(PCVAL_NULL == 0);
void
js_PurgePropertyCache(JSContext *cx, JSPropertyCache *cache)
{
if (cache->empty) {
ASSERT_CACHE_IS_EMPTY(cache);
return;
}
memset(cache->table, 0, sizeof cache->table);
cache->empty = JS_TRUE;
#ifdef JS_PROPERTY_CACHE_METERING
{ static FILE *fp;
if (!fp)
fp = fopen("/tmp/propcache.stats", "w");
if (fp) {
fputs("Property cache stats for ", fp);
#ifdef JS_THREADSAFE
fprintf(fp, "thread %lu, ", (unsigned long) cx->thread->id);
#endif
fprintf(fp, "GC %u\n", cx->runtime->gcNumber);
# define P(mem) fprintf(fp, "%11s %10lu\n", #mem, (unsigned long)cache->mem)
P(fills);
P(nofills);
P(rofills);
P(disfills);
P(oddfills);
P(modfills);
P(brandfills);
P(noprotos);
P(longchains);
P(recycles);
P(pcrecycles);
P(tests);
P(pchits);
P(protopchits);
P(initests);
P(inipchits);
P(inipcmisses);
P(settests);
P(addpchits);
P(setpchits);
P(setpcmisses);
P(slotchanges);
P(setmisses);
P(idmisses);
P(komisses);
P(vcmisses);
P(misses);
P(flushes);
P(pcpurges);
# undef P
fprintf(fp, "hit rates: pc %g%% (proto %g%%), set %g%%, ini %g%%, full %g%%\n",
(100. * cache->pchits) / cache->tests,
(100. * cache->protopchits) / cache->tests,
(100. * (cache->addpchits + cache->setpchits))
/ cache->settests,
(100. * cache->inipchits) / cache->initests,
(100. * (cache->tests - cache->misses)) / cache->tests);
fflush(fp);
}
}
#endif
PCMETER(cache->flushes++);
}
void
js_PurgePropertyCacheForScript(JSContext *cx, JSScript *script)
{
JSPropertyCache *cache;
JSPropCacheEntry *entry;
cache = &JS_PROPERTY_CACHE(cx);
for (entry = cache->table; entry < cache->table + PROPERTY_CACHE_SIZE;
entry++) {
if (JS_UPTRDIFF(entry->kpc, script->code) < script->length) {
entry->kpc = NULL;
entry->kshape = 0;
#ifdef DEBUG
entry->vcap = entry->vword = 0;
#endif
}
}
}

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sw=4 et tw=79:
*
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla Communicator client code, released
* March 31, 1998.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifndef jspropcache_h___
#define jspropcache_h___
/*
* Property cache with structurally typed capabilities for invalidation, for
* polymorphic callsite method/get/set speedups. For details, see
* <https://developer.mozilla.org/en/SpiderMonkey/Internals/Property_cache>.
*/
#define PROPERTY_CACHE_LOG2 12
#define PROPERTY_CACHE_SIZE JS_BIT(PROPERTY_CACHE_LOG2)
#define PROPERTY_CACHE_MASK JS_BITMASK(PROPERTY_CACHE_LOG2)
/*
* Add kshape rather than xor it to avoid collisions between nearby bytecode
* that are evolving an object by setting successive properties, incrementing
* the object's scope->shape on each set.
*/
#define PROPERTY_CACHE_HASH(pc,kshape) \
(((((jsuword)(pc) >> PROPERTY_CACHE_LOG2) ^ (jsuword)(pc)) + (kshape)) & \
PROPERTY_CACHE_MASK)
#define PROPERTY_CACHE_HASH_PC(pc,kshape) \
PROPERTY_CACHE_HASH(pc, kshape)
#define PROPERTY_CACHE_HASH_ATOM(atom,obj) \
PROPERTY_CACHE_HASH((jsuword)(atom) >> 2, OBJ_SHAPE(obj))
/*
* Property cache value capability macros.
*/
#define PCVCAP_PROTOBITS 4
#define PCVCAP_PROTOSIZE JS_BIT(PCVCAP_PROTOBITS)
#define PCVCAP_PROTOMASK JS_BITMASK(PCVCAP_PROTOBITS)
#define PCVCAP_SCOPEBITS 4
#define PCVCAP_SCOPESIZE JS_BIT(PCVCAP_SCOPEBITS)
#define PCVCAP_SCOPEMASK JS_BITMASK(PCVCAP_SCOPEBITS)
#define PCVCAP_TAGBITS (PCVCAP_PROTOBITS + PCVCAP_SCOPEBITS)
#define PCVCAP_TAGMASK JS_BITMASK(PCVCAP_TAGBITS)
#define PCVCAP_TAG(t) ((t) & PCVCAP_TAGMASK)
#define PCVCAP_MAKE(t,s,p) ((uint32(t) << PCVCAP_TAGBITS) | \
((s) << PCVCAP_PROTOBITS) | \
(p))
#define PCVCAP_SHAPE(t) ((t) >> PCVCAP_TAGBITS)
#define SHAPE_OVERFLOW_BIT JS_BIT(32 - PCVCAP_TAGBITS)
struct JSPropCacheEntry {
jsbytecode *kpc; /* pc if vcap tag is <= 1, else atom */
jsuword kshape; /* key shape if pc, else obj for atom */
jsuword vcap; /* value capability, see above */
jsuword vword; /* value word, see PCVAL_* below */
bool adding() const {
return PCVCAP_TAG(vcap) == 0 && kshape != PCVCAP_SHAPE(vcap);
}
bool directHit() const {
return PCVCAP_TAG(vcap) == 0 && kshape == PCVCAP_SHAPE(vcap);
}
};
/*
* Special value for functions returning JSPropCacheEntry * to distinguish
* between failure and no no-cache-fill cases.
*/
#define JS_NO_PROP_CACHE_FILL ((JSPropCacheEntry *) NULL + 1)
#if defined DEBUG_brendan || defined DEBUG_brendaneich
#define JS_PROPERTY_CACHE_METERING 1
#endif
typedef struct JSPropertyCache {
JSPropCacheEntry table[PROPERTY_CACHE_SIZE];
JSBool empty;
#ifdef JS_PROPERTY_CACHE_METERING
JSPropCacheEntry *pctestentry; /* entry of the last PC-based test */
uint32 fills; /* number of cache entry fills */
uint32 nofills; /* couldn't fill (e.g. default get) */
uint32 rofills; /* set on read-only prop can't fill */
uint32 disfills; /* fill attempts on disabled cache */
uint32 oddfills; /* fill attempt after setter deleted */
uint32 modfills; /* fill that rehashed to a new entry */
uint32 brandfills; /* scope brandings to type structural
method fills */
uint32 noprotos; /* resolve-returned non-proto pobj */
uint32 longchains; /* overlong scope and/or proto chain */
uint32 recycles; /* cache entries recycled by fills */
uint32 pcrecycles; /* pc-keyed entries recycled by atom-
keyed fills */
uint32 tests; /* cache probes */
uint32 pchits; /* fast-path polymorphic op hits */
uint32 protopchits; /* pchits hitting immediate prototype */
uint32 initests; /* cache probes from JSOP_INITPROP */
uint32 inipchits; /* init'ing next property pchit case */
uint32 inipcmisses; /* init'ing next property pc misses */
uint32 settests; /* cache probes from JOF_SET opcodes */
uint32 addpchits; /* adding next property pchit case */
uint32 setpchits; /* setting existing property pchit */
uint32 setpcmisses; /* setting/adding property pc misses */
uint32 slotchanges; /* clasp->reserveSlots result variance-
induced slot changes */
uint32 setmisses; /* JSOP_SET{NAME,PROP} total misses */
uint32 idmisses; /* slow-path key id == atom misses */
uint32 komisses; /* slow-path key object misses */
uint32 vcmisses; /* value capability misses */
uint32 misses; /* cache misses */
uint32 flushes; /* cache flushes */
uint32 pcpurges; /* shadowing purges on proto chain */
# define PCMETER(x) x
#else
# define PCMETER(x) ((void)0)
#endif
} JSPropertyCache;
/*
* Property cache value tagging/untagging macros.
*/
#define PCVAL_OBJECT 0
#define PCVAL_SLOT 1
#define PCVAL_SPROP 2
#define PCVAL_TAGBITS 2
#define PCVAL_TAGMASK JS_BITMASK(PCVAL_TAGBITS)
#define PCVAL_TAG(v) ((v) & PCVAL_TAGMASK)
#define PCVAL_CLRTAG(v) ((v) & ~(jsuword)PCVAL_TAGMASK)
#define PCVAL_SETTAG(v,t) ((jsuword)(v) | (t))
#define PCVAL_NULL 0
#define PCVAL_IS_NULL(v) ((v) == PCVAL_NULL)
#define PCVAL_IS_OBJECT(v) (PCVAL_TAG(v) == PCVAL_OBJECT)
#define PCVAL_TO_OBJECT(v) ((JSObject *) (v))
#define OBJECT_TO_PCVAL(obj) ((jsuword) (obj))
#define PCVAL_OBJECT_TO_JSVAL(v) OBJECT_TO_JSVAL(PCVAL_TO_OBJECT(v))
#define JSVAL_OBJECT_TO_PCVAL(v) OBJECT_TO_PCVAL(JSVAL_TO_OBJECT(v))
#define PCVAL_IS_SLOT(v) ((v) & PCVAL_SLOT)
#define PCVAL_TO_SLOT(v) ((jsuint)(v) >> 1)
#define SLOT_TO_PCVAL(i) (((jsuword)(i) << 1) | PCVAL_SLOT)
#define PCVAL_IS_SPROP(v) (PCVAL_TAG(v) == PCVAL_SPROP)
#define PCVAL_TO_SPROP(v) ((JSScopeProperty *) PCVAL_CLRTAG(v))
#define SPROP_TO_PCVAL(sprop) PCVAL_SETTAG(sprop, PCVAL_SPROP)
/*
* Fill property cache entry for key cx->fp->pc, optimized value word computed
* from obj and sprop, and entry capability forged from 24-bit OBJ_SHAPE(obj),
* 4-bit scopeIndex, and 4-bit protoIndex.
*
* Return the filled cache entry or JS_NO_PROP_CACHE_FILL if caching was not
* possible.
*/
extern JS_REQUIRES_STACK JSPropCacheEntry *
js_FillPropertyCache(JSContext *cx, JSObject *obj,
uintN scopeIndex, uintN protoIndex, JSObject *pobj,
JSScopeProperty *sprop, JSBool adding);
/*
* Property cache lookup macros. PROPERTY_CACHE_TEST is designed to inline the
* fast path in js_Interpret, so it makes "just-so" restrictions on parameters,
* e.g. pobj and obj should not be the same variable, since for JOF_PROP-mode
* opcodes, obj must not be changed because of a cache miss.
*
* On return from PROPERTY_CACHE_TEST, if atom is null then obj points to the
* scope chain element in which the property was found, pobj is locked, and
* entry is valid. If atom is non-null then no object is locked but entry is
* still set correctly for use, e.g., by js_FillPropertyCache and atom should
* be used as the id to find.
*
* We must lock pobj on a hit in order to close races with threads that might
* be deleting a property from its scope, or otherwise invalidating property
* caches (on all threads) by re-generating scope->shape.
*/
#define PROPERTY_CACHE_TEST(cx, pc, obj, pobj, entry, atom) \
do { \
JSPropertyCache *cache_ = &JS_PROPERTY_CACHE(cx); \
uint32 kshape_ = (JS_ASSERT(OBJ_IS_NATIVE(obj)), OBJ_SHAPE(obj)); \
entry = &cache_->table[PROPERTY_CACHE_HASH_PC(pc, kshape_)]; \
PCMETER(cache_->pctestentry = entry); \
PCMETER(cache_->tests++); \
JS_ASSERT(&obj != &pobj); \
if (entry->kpc == pc && entry->kshape == kshape_) { \
JSObject *tmp_; \
pobj = obj; \
JS_ASSERT(PCVCAP_TAG(entry->vcap) <= 1); \
if (PCVCAP_TAG(entry->vcap) == 1 && \
(tmp_ = OBJ_GET_PROTO(cx, pobj)) != NULL) { \
pobj = tmp_; \
} \
\
if (JS_LOCK_OBJ_IF_SHAPE(cx, pobj, PCVCAP_SHAPE(entry->vcap))) { \
PCMETER(cache_->pchits++); \
PCMETER(!PCVCAP_TAG(entry->vcap) || cache_->protopchits++); \
atom = NULL; \
break; \
} \
} \
atom = js_FullTestPropertyCache(cx, pc, &obj, &pobj, &entry); \
if (atom) \
PCMETER(cache_->misses++); \
} while (0)
extern JS_REQUIRES_STACK JSAtom *
js_FullTestPropertyCache(JSContext *cx, jsbytecode *pc,
JSObject **objp, JSObject **pobjp,
JSPropCacheEntry **entryp);
/* The property cache does not need a destructor. */
#define js_FinishPropertyCache(cache) ((void) 0)
extern void
js_PurgePropertyCache(JSContext *cx, JSPropertyCache *cache);
extern void
js_PurgePropertyCacheForScript(JSContext *cx, JSScript *script);
#endif /* jspropcache_h___ */