Changeset 49717 in webkit for trunk/JavaScriptCore/runtime/JSPropertyNameIterator.cpp

Timestamp:

Oct 16, 2009, 5:28:19 PM (16 years ago)

Author:

[email protected]

Message:

Fast for-in enumeration: Cache JSPropertyNameIterator; cache JSStrings
in JSPropertyNameIterator; inline more code.

Patch by Geoffrey Garen <​[email protected]> on 2009-10-16
Reviewed by Oliver Hunt.

1.024x as fast on SunSpider (fasta: 1.43x as fast).

• bytecode/CodeBlock.cpp:

(JSC::CodeBlock::dump):

• bytecode/Opcode.h:
• bytecompiler/BytecodeGenerator.cpp:

(JSC::BytecodeGenerator::emitGetPropertyNames):
(JSC::BytecodeGenerator::emitNextPropertyName):

• bytecompiler/BytecodeGenerator.h: Added a few extra operands to

op_get_pnames and op_next_pname so that we can track iteration state
in the register file instead of in the JSPropertyNameIterator. (To be
cacheable, the JSPropertyNameIterator must be stateless.)

• interpreter/Interpreter.cpp:

(JSC::Interpreter::tryCachePutByID):
(JSC::Interpreter::tryCacheGetByID): Updated for rename to
"normalizePrototypeChain" and removal of "isCacheable".

(JSC::Interpreter::privateExecute): Updated for in-RegisterFile
iteration state tracking.

• jit/JIT.cpp:

(JSC::JIT::privateCompileMainPass):

• jit/JIT.h:
• jit/JITOpcodes.cpp:

(JSC::JIT::emit_op_get_pnames): Updated for in-RegisterFile
iteration state tracking.

(JSC::JIT::emit_op_next_pname): Inlined code generation for op_next_pname.

• jit/JITStubs.cpp:

(JSC::JITThunks::tryCachePutByID):
(JSC::JITThunks::tryCacheGetByID): Updated for rename to
"normalizePrototypeChain" and removal of "isCacheable".

(JSC::DEFINE_STUB_FUNCTION):

• jit/JITStubs.h:

(JSC::): Added has_property and to_object stubs. Removed op_next_pname
stub, since has_property is all we need anymore.

• parser/Nodes.cpp:

(JSC::ForInNode::emitBytecode): Updated for in-RegisterFile
iteration state tracking.

• runtime/JSCell.h:
• runtime/JSObject.cpp:

(JSC::JSObject::getPropertyNames): Don't do caching at this layer
anymore, since we don't create a JSPropertyNameIterator at this layer.

• runtime/JSPropertyNameIterator.cpp:

(JSC::JSPropertyNameIterator::create): Do do caching at this layer.
(JSC::JSPropertyNameIterator::get): Updated for in-RegisterFile
iteration state tracking.
(JSC::JSPropertyNameIterator::markChildren): Mark our JSStrings.

• runtime/JSPropertyNameIterator.h:

(JSC::JSPropertyNameIterator::size):
(JSC::JSPropertyNameIterator::setCachedStructure):
(JSC::JSPropertyNameIterator::cachedStructure):
(JSC::JSPropertyNameIterator::setCachedPrototypeChain):
(JSC::JSPropertyNameIterator::cachedPrototypeChain):
(JSC::JSPropertyNameIterator::JSPropertyNameIterator):
(JSC::Structure::setEnumerationCache): Don't store iteration state in
a JSPropertyNameIterator. Do cache a JSPropertyNameIterator in a
Structure.

• runtime/JSValue.h:

(JSC::asCell):

• runtime/MarkStack.h: Make those mischievous #include gods happy.

• runtime/ObjectConstructor.cpp:

• runtime/Operations.h:

(JSC::normalizePrototypeChain): Renamed countPrototypeChainEntriesAndCheckForProxies
to normalizePrototypeChain, since it changes dictionary prototypes to
non-dictionary objects.

• runtime/PropertyNameArray.cpp:

(JSC::PropertyNameArray::add):

• runtime/PropertyNameArray.h:

(JSC::PropertyNameArrayData::PropertyNameArrayData):
(JSC::PropertyNameArray::data):
(JSC::PropertyNameArray::size):
(JSC::PropertyNameArray::begin):
(JSC::PropertyNameArray::end): Simplified some code here to help with
current and future refactoring.

• runtime/Protect.h:
• runtime/Structure.cpp:

(JSC::Structure::~Structure):
(JSC::Structure::addPropertyWithoutTransition):
(JSC::Structure::removePropertyWithoutTransition): No need to clear
the enumeration cache with adding / removing properties without
transition. It is an error to add / remove properties without transition
once an object has been observed, and we can ASSERT to catch that.

• runtime/Structure.h:

(JSC::Structure::enumerationCache): Changed the enumeration cache to
hold a JSPropertyNameIterator.

• runtime/StructureChain.cpp:
• runtime/StructureChain.h:

(JSC::StructureChain::head): Removed StructureChain::isCacheable because
it was wrong-headed in two ways: (1) It gave up when a prototype was a
dictionary, but instead we want un-dictionary heavily accessed
prototypes; (2) It folded a test for hasDefaultGetPropertyNames() into
a generic test for "cacheable-ness", but hasDefaultGetPropertyNames()
is only releavant to for-in caching.

File:

• trunk/JavaScriptCore/runtime/JSPropertyNameIterator.cpp (modified) (1 diff)

trunk/JavaScriptCore/runtime/JSPropertyNameIterator.cpp

@@ -30 +30 @@
 #include "JSPropertyNameIterator.h"
 
+#include "JSGlobalObject.h"
+
 namespace JSC {
 
 ASSERT_CLASS_FITS_IN_CELL(JSPropertyNameIterator);
 
-JSPropertyNameIterator::~JSPropertyNameIterator()
+JSPropertyNameIterator* JSPropertyNameIterator::create(ExecState* exec, JSObject* o)
 {
+    ASSERT(!o->structure()->enumerationCache() ||
+            o->structure()->enumerationCache()->cachedStructure() != o->structure() ||
+            o->structure()->enumerationCache()->cachedPrototypeChain() != o->structure()->prototypeChain(exec));
+
+    PropertyNameArray propertyNames(exec);
+    o->getPropertyNames(exec, propertyNames);
+    JSPropertyNameIterator* jsPropertyNameIterator = new (exec) JSPropertyNameIterator(exec, propertyNames.data());
+
+    if (o->structure()->isDictionary())
+        return jsPropertyNameIterator;
+
+    if (o->structure()->typeInfo().overridesGetPropertyNames())
+        return jsPropertyNameIterator;
+    
+    size_t count = normalizePrototypeChain(exec, o);
+    StructureChain* structureChain = o->structure()->prototypeChain(exec);
+    RefPtr<Structure>* structure = structureChain->head();
+    for (size_t i = 0; i < count; ++i) {
+        if (structure[i]->typeInfo().overridesGetPropertyNames())
+            return jsPropertyNameIterator;
+    }
+
+    jsPropertyNameIterator->setCachedPrototypeChain(structureChain);
+    jsPropertyNameIterator->setCachedStructure(o->structure());
+    o->structure()->setEnumerationCache(jsPropertyNameIterator);
+    return jsPropertyNameIterator;
+}
+
+JSValue JSPropertyNameIterator::get(ExecState* exec, JSObject* base, size_t i)
+{
+    JSValue& identifier = m_jsStrings[i];
+    if (m_cachedStructure == base->structure() && m_cachedPrototypeChain == base->structure()->prototypeChain(exec))
+        return identifier;
+
+    if (!base->hasProperty(exec, Identifier(exec, asString(identifier)->value())))
+        return JSValue();
+    return identifier;
 }
 
 void JSPropertyNameIterator::markChildren(MarkStack& markStack)
 {
-    JSCell::markChildren(markStack);
-    if (m_object)
-        markStack.append(m_object);
-}
-
-void JSPropertyNameIterator::invalidate()
-{
-    ASSERT(m_position == m_end);
-    m_object = 0;
-    m_data.clear();
+    markStack.appendValues(m_jsStrings.get(), m_jsStringsSize, MayContainNullValues);
 }