Diff
Modified: trunk/LayoutTests/ChangeLog (175845 => 175846)
--- trunk/LayoutTests/ChangeLog 2014-11-11 03:05:25 UTC (rev 175845)
+++ trunk/LayoutTests/ChangeLog 2014-11-11 03:10:13 UTC (rev 175846)
@@ -1,3 +1,27 @@
+2014-11-10 Andreas Kling <akl...@apple.com>
+
+ The JIT should cache property lookup misses.
+ <https://webkit.org/b/135578>
+
+ Add a JSRegress test for caching of property lookup misses.
+ There are three subtests:
+
+ 1. Pure speed test.
+ 2. Test for when a property previously cached as missing suddenly
+ appears on the object.
+ 3. Same as (2), but it appears on the prototype.
+
+ The test runs ~5.5x faster with the optimization.
+
+ Reviewed by Filip Pizlo.
+
+ * js/regress/script-tests/undefined-property-access.js: Added.
+ (foo):
+ (bar):
+ (baz):
+ * js/regress/undefined-property-access-expected.txt: Added.
+ * js/regress/undefined-property-access.html: Added.
+
2014-11-10 Myles C. Maxfield <mmaxfi...@apple.com>
Test that complext and fast text codepaths measure the same width
Added: trunk/LayoutTests/js/regress/script-tests/undefined-property-access.js (0 => 175846)
--- trunk/LayoutTests/js/regress/script-tests/undefined-property-access.js (rev 0)
+++ trunk/LayoutTests/js/regress/script-tests/undefined-property-access.js 2014-11-11 03:10:13 UTC (rev 175846)
@@ -0,0 +1,48 @@
+var someGlobal;
+
+// This is a simple speed test. It should go fast.
+
+function foo() {
+ var myObject = {};
+ for (var i = 0; i < 10000000; ++i) {
+ someGlobal = myObject.undefinedProperty;
+ }
+ return someGlobal;
+}
+result = foo();
+if (result != undefined)
+ throw "Bad result: " + result;
+
+// This test checks that a cached property lookup miss doesn't continue to fire when the property suddenly appears on the object.
+
+function bar() {
+ var myObject = {};
+ for (var i = 0; i < 100000000; ++i) {
+ someGlobal = myObject.someProperty;
+ if (i == 50000000)
+ myObject.someProperty = 1;
+ }
+ return someGlobal;
+}
+var result = bar();
+if (result != 1)
+ throw "Bad result: " + result;
+someGlobal = undefined;
+
+// This test checks that a cached property lookup miss doesn't continue to fire when the property suddenly appears on the object's prototype.
+
+function baz() {
+ var myPrototype = {}
+ var myObject = {};
+ myObject.__proto__ = myPrototype;
+ for (var i = 0; i < 100000000; ++i) {
+ someGlobal = myObject.someProperty;
+ if (i == 50000000)
+ myPrototype.someProperty = 2;
+ }
+ return someGlobal;
+}
+var result = baz();
+if (result != 2)
+ throw "Bad result: " + result;
+
Added: trunk/LayoutTests/js/regress/undefined-property-access-expected.txt (0 => 175846)
--- trunk/LayoutTests/js/regress/undefined-property-access-expected.txt (rev 0)
+++ trunk/LayoutTests/js/regress/undefined-property-access-expected.txt 2014-11-11 03:10:13 UTC (rev 175846)
@@ -0,0 +1,10 @@
+JSRegress/undefined-property-access
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+PASS no exception thrown
+PASS successfullyParsed is true
+
+TEST COMPLETE
+
Added: trunk/LayoutTests/js/regress/undefined-property-access.html (0 => 175846)
--- trunk/LayoutTests/js/regress/undefined-property-access.html (rev 0)
+++ trunk/LayoutTests/js/regress/undefined-property-access.html 2014-11-11 03:10:13 UTC (rev 175846)
@@ -0,0 +1,12 @@
+<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN">
+<html>
+<head>
+<script src=""
+</head>
+<body>
+<script src=""
+<script src=""
+<script src=""
+<script src=""
+</body>
+</html>
Modified: trunk/Source/_javascript_Core/ChangeLog (175845 => 175846)
--- trunk/Source/_javascript_Core/ChangeLog 2014-11-11 03:05:25 UTC (rev 175845)
+++ trunk/Source/_javascript_Core/ChangeLog 2014-11-11 03:10:13 UTC (rev 175846)
@@ -1,3 +1,41 @@
+2014-11-10 Andreas Kling <akl...@apple.com>
+
+ The JIT should cache property lookup misses.
+ <https://webkit.org/b/135578>
+
+ Add support for inline caching of missed property lookups.
+ Previously this would banish us to C++ slow path.
+
+ It's implemented as a simple GetById cache that returns jsUndefined()
+ as long as the Structure chain check passes. There's no DFG exploitation
+ of this knowledge in this patch.
+
+ Test: js/regress/undefined-property-access.js (~5.5x speedup)
+
+ Reviewed by Filip Pizlo.
+
+ * bytecode/PolymorphicGetByIdList.h:
+ * bytecode/GetByIdStatus.cpp:
+ (JSC::GetByIdStatus::computeForStubInfo):
+
+ Add GetByIdAccess::SimpleMiss so we can communicate to the DFG that
+ the access has been cached.
+
+ * jit/Repatch.cpp:
+ (JSC::toString):
+ (JSC::kindFor):
+ (JSC::generateByIdStub):
+ (JSC::tryCacheGetByID):
+ (JSC::tryBuildGetByIDList):
+
+ Added a GetUndefined stub kind, just a simple "store jsUndefined()" snippet.
+ Use this to cache missed lookups, piggybacking mostly on the GetValue kind.
+
+ * runtime/PropertySlot.h:
+ (JSC::PropertySlot::isUnset):
+
+ Exposed the unset state so PropertySlot can communicate that lookup failed.
+
2014-11-10 Michael Saboff <msab...@apple.com>
Add scope operand to op_create_lexical_environment
Modified: trunk/Source/_javascript_Core/bytecode/GetByIdStatus.cpp (175845 => 175846)
--- trunk/Source/_javascript_Core/bytecode/GetByIdStatus.cpp 2014-11-11 03:05:25 UTC (rev 175845)
+++ trunk/Source/_javascript_Core/bytecode/GetByIdStatus.cpp 2014-11-11 03:10:13 UTC (rev 175846)
@@ -189,6 +189,7 @@
locker, profiledBlock, *stub->m_callLinkInfo, callExitSiteData));
break;
}
+ case GetByIdAccess::SimpleMiss:
case GetByIdAccess::CustomGetter:
case GetByIdAccess::WatchedStub:{
// FIXME: It would be totally sweet to support this at some point in the future.
Modified: trunk/Source/_javascript_Core/bytecode/PolymorphicGetByIdList.h (175845 => 175846)
--- trunk/Source/_javascript_Core/bytecode/PolymorphicGetByIdList.h 2014-11-11 03:05:25 UTC (rev 175845)
+++ trunk/Source/_javascript_Core/bytecode/PolymorphicGetByIdList.h 2014-11-11 03:10:13 UTC (rev 175846)
@@ -47,7 +47,8 @@
SimpleStub, // This is a stub.
WatchedStub,
Getter,
- CustomGetter
+ CustomGetter,
+ SimpleMiss,
};
GetByIdAccess()
Modified: trunk/Source/_javascript_Core/jit/Repatch.cpp (175845 => 175846)
--- trunk/Source/_javascript_Core/jit/Repatch.cpp 2014-11-11 03:05:25 UTC (rev 175845)
+++ trunk/Source/_javascript_Core/jit/Repatch.cpp 2014-11-11 03:10:13 UTC (rev 175846)
@@ -228,6 +228,7 @@
enum ByIdStubKind {
GetValue,
+ GetUndefined,
CallGetter,
CallCustomGetter,
CallSetter,
@@ -239,6 +240,8 @@
switch (kind) {
case GetValue:
return "GetValue";
+ case GetUndefined:
+ return "GetUndefined";
case CallGetter:
return "CallGetter";
case CallCustomGetter:
@@ -257,6 +260,8 @@
{
if (slot.isCacheableValue())
return GetValue;
+ if (slot.isUnset())
+ return GetUndefined;
if (slot.isCacheableCustom())
return CallCustomGetter;
RELEASE_ASSERT(slot.isCacheableGetter());
@@ -301,7 +306,7 @@
static_cast<GPRReg>(stubInfo.patch.valueGPR));
GPRReg scratchGPR = TempRegisterSet(stubInfo.patch.usedRegisters).getFreeGPR();
bool needToRestoreScratch = scratchGPR == InvalidGPRReg;
- RELEASE_ASSERT(!needToRestoreScratch || kind == GetValue);
+ RELEASE_ASSERT(!needToRestoreScratch || (kind == GetValue || kind == GetUndefined));
CCallHelpers stubJit(&exec->vm(), exec->codeBlock());
if (needToRestoreScratch) {
@@ -361,24 +366,28 @@
}
currStructure->startWatchingPropertyForReplacements(*vm, offset);
- GPRReg baseForAccessGPR;
- if (chain) {
- // We could have clobbered scratchGPR earlier, so we have to reload from baseGPR to get the target.
- if (loadTargetFromProxy)
- stubJit.loadPtr(MacroAssembler::Address(baseGPR, JSProxy::targetOffset()), baseForGetGPR);
- stubJit.move(MacroAssembler::TrustedImmPtr(protoObject), scratchGPR);
- baseForAccessGPR = scratchGPR;
- } else {
- // For proxy objects, we need to do all the Structure checks before moving the baseGPR into
- // baseForGetGPR because if we fail any of the checks then we would have the wrong value in baseGPR
- // on the slow path.
- if (loadTargetFromProxy)
- stubJit.move(scratchGPR, baseForGetGPR);
- baseForAccessGPR = baseForGetGPR;
+ GPRReg baseForAccessGPR = InvalidGPRReg;
+ if (kind != GetUndefined) {
+ if (chain) {
+ // We could have clobbered scratchGPR earlier, so we have to reload from baseGPR to get the target.
+ if (loadTargetFromProxy)
+ stubJit.loadPtr(MacroAssembler::Address(baseGPR, JSProxy::targetOffset()), baseForGetGPR);
+ stubJit.move(MacroAssembler::TrustedImmPtr(protoObject), scratchGPR);
+ baseForAccessGPR = scratchGPR;
+ } else {
+ // For proxy objects, we need to do all the Structure checks before moving the baseGPR into
+ // baseForGetGPR because if we fail any of the checks then we would have the wrong value in baseGPR
+ // on the slow path.
+ if (loadTargetFromProxy)
+ stubJit.move(scratchGPR, baseForGetGPR);
+ baseForAccessGPR = baseForGetGPR;
+ }
}
GPRReg loadedValueGPR = InvalidGPRReg;
- if (kind != CallCustomGetter && kind != CallCustomSetter) {
+ if (kind == GetUndefined)
+ stubJit.moveTrustedValue(jsUndefined(), valueRegs);
+ else if (kind != CallCustomGetter && kind != CallCustomSetter) {
if (kind == GetValue)
loadedValueGPR = valueRegs.payloadGPR();
else
@@ -412,7 +421,7 @@
std::unique_ptr<CallLinkInfo> callLinkInfo;
MacroAssembler::Jump success, fail;
- if (kind != GetValue) {
+ if (kind != GetValue && kind != GetUndefined) {
// Need to make sure that whenever this call is made in the future, we remember the
// place that we made it from. It just so happens to be the place that we are at
// right now!
@@ -733,10 +742,12 @@
// FIXME: Cache property access for immediates.
if (!baseValue.isCell())
return GiveUpOnCache;
+
+ if (!slot.isCacheable() && !slot.isUnset())
+ return GiveUpOnCache;
+
JSCell* baseCell = baseValue.asCell();
Structure* structure = baseCell->structure();
- if (!slot.isCacheable())
- return GiveUpOnCache;
InlineCacheAction action = "" baseCell);
if (action != AttemptToCache)
@@ -783,7 +794,7 @@
static InlineCacheAction tryBuildGetByIDList(ExecState* exec, JSValue baseValue, const Identifier& ident, const PropertySlot& slot, StructureStubInfo& stubInfo)
{
if (!baseValue.isCell()
- || !slot.isCacheable())
+ || (!slot.isCacheable() && !slot.isUnset()))
return GiveUpOnCache;
JSCell* baseCell = baseValue.asCell();
@@ -808,20 +819,23 @@
// We cannot do as much inline caching if the registers were not flushed prior to this GetById. In particular,
// non-Value cached properties require planting calls, which requires registers to have been flushed. Thus,
// if registers were not flushed, don't do non-Value caching.
- if (!slot.isCacheableValue())
+ if (!slot.isCacheableValue() && !slot.isUnset())
return GiveUpOnCache;
}
-
- PropertyOffset offset = slot.cachedOffset();
+
+ PropertyOffset offset = slot.isUnset() ? invalidOffset : slot.cachedOffset();
StructureChain* prototypeChain = 0;
size_t count = 0;
- if (slot.slotBase() != baseValue) {
+ if (slot.isUnset() || slot.slotBase() != baseValue) {
if (typeInfo.prohibitsPropertyCaching() || structure->isDictionary())
return GiveUpOnCache;
-
- count = normalizePrototypeChainForChainAccess(
- exec, baseValue, slot.slotBase(), ident, offset);
+
+ if (slot.isUnset())
+ count = normalizePrototypeChain(exec, baseCell);
+ else
+ count = normalizePrototypeChainForChainAccess(
+ exec, baseValue, slot.slotBase(), ident, offset);
if (count == InvalidPrototypeChain)
return GiveUpOnCache;
prototypeChain = structure->prototypeChain(exec);
@@ -843,6 +857,8 @@
GetByIdAccess::AccessType accessType;
if (slot.isCacheableValue())
accessType = slot.watchpointSet() ? GetByIdAccess::WatchedStub : GetByIdAccess::SimpleStub;
+ else if (slot.isUnset())
+ accessType = GetByIdAccess::SimpleMiss;
else if (slot.isCacheableGetter())
accessType = GetByIdAccess::Getter;
else
Modified: trunk/Source/_javascript_Core/runtime/PropertySlot.h (175845 => 175846)
--- trunk/Source/_javascript_Core/runtime/PropertySlot.h 2014-11-11 03:05:25 UTC (rev 175845)
+++ trunk/Source/_javascript_Core/runtime/PropertySlot.h 2014-11-11 03:10:13 UTC (rev 175846)
@@ -78,6 +78,7 @@
JSValue getValue(ExecState*, unsigned propertyName) const;
bool isCacheable() const { return m_cacheability == CachingAllowed && m_offset != invalidOffset; }
+ bool isUnset() const { return m_propertyType == TypeUnset; }
bool isValue() const { return m_propertyType == TypeValue; }
bool isAccessor() const { return m_propertyType == TypeGetter; }
bool isCustom() const { return m_propertyType == TypeCustom; }
