Changeset 154199 in webkit for trunk/Source/JavaScriptCore/runtime/Structure.cpp

Timestamp:

Aug 16, 2013, 12:15:31 PM (12 years ago)

Author:

[email protected]

Message:

Object properties added using dot syntax (o.f = ...) from code that isn't in eval should be less likely to cause an object to become a dictionary
​https://bugs.webkit.org/show_bug.cgi?id=119897

Source/JavaScriptCore:

Reviewed by Oliver Hunt.

6-10x speed-up on microbenchmarks that create large static objects. 40-65% speed-up
on Octane/gbemu. 3% overall speed-up on Octane. No slow-downs anywhere; our ability
to turn objects into dictionaries when you're storing using bracket syntax or using
eval is still in place.

• bytecode/CodeBlock.h:

(JSC::CodeBlock::putByIdContext):

• dfg/DFGOperations.cpp:
• jit/JITStubs.cpp:

(JSC::DEFINE_STUB_FUNCTION):

• llint/LLIntSlowPaths.cpp:

(JSC::LLInt::LLINT_SLOW_PATH_DECL):

• runtime/JSObject.h:

(JSC::JSObject::putDirectInternal):

• runtime/PutPropertySlot.h:

(JSC::PutPropertySlot::PutPropertySlot):
(JSC::PutPropertySlot::context):

• runtime/Structure.cpp:

(JSC::Structure::addPropertyTransition):

• runtime/Structure.h:

LayoutTests:

Reviewed by Oliver Hunt.

• fast/js/regress/lots-of-fields-expected.txt: Added.
• fast/js/regress/lots-of-fields.html: Added.
• fast/js/regress/script-tests/lots-of-fields.js: Added.

(foo):

File:

• trunk/Source/JavaScriptCore/runtime/Structure.cpp (modified) (2 diffs)

trunk/Source/JavaScriptCore/runtime/Structure.cpp

@@ -381 +381 @@
 }
 
-Structure* Structure::addPropertyTransition(VM& vm, Structure* structure, PropertyName propertyName, unsigned attributes, JSCell* specificValue, PropertyOffset& offset)
+Structure* Structure::addPropertyTransition(VM& vm, Structure* structure, PropertyName propertyName, unsigned attributes, JSCell* specificValue, PropertyOffset& offset, PutPropertySlot::Context context)
 {
     // If we have a specific function, we may have got to this point if there is
@@ -400 +400 @@
         specificValue = 0;
 
-    if (structure->transitionCount() > s_maxTransitionLength) {
+    int maxTransitionLength;
+    if (context == PutPropertySlot::PutById)
+        maxTransitionLength = s_maxTransitionLengthForNonEvalPutById;
+    else
+        maxTransitionLength = s_maxTransitionLength;
+    if (structure->transitionCount() > maxTransitionLength) {
         Structure* transition = toCacheableDictionaryTransition(vm, structure);
         ASSERT(structure != transition);