Changeset 222421 in webkit for trunk/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp

Timestamp:

Sep 22, 2017, 7:08:04 PM (8 years ago)

Author:

[email protected]

Message:

Speculatively change iteration protocall to use the same next function
​https://bugs.webkit.org/show_bug.cgi?id=175653

Reviewed by Saam Barati.

JSTests:

Change test to match the new iteration behavior.

• stress/spread-optimized-properly.js:

Source/JavaScriptCore:

This patch speculatively makes a change to the iteration protocall to fetch the next
property immediately after calling the Symbol.iterator function. This is, in theory,
a breaking change, so we will see if this breaks things (most likely it won't as this
is a relatively subtle point).

See: ​https://github.com/tc39/ecma262/issues/976

• builtins/IteratorHelpers.js:

(performIteration):

• bytecompiler/BytecodeGenerator.cpp:

(JSC::BytecodeGenerator::emitEnumeration):
(JSC::BytecodeGenerator::emitIteratorNext):
(JSC::BytecodeGenerator::emitIteratorNextWithValue):
(JSC::BytecodeGenerator::emitDelegateYield):

• bytecompiler/BytecodeGenerator.h:
• bytecompiler/NodesCodegen.cpp:

(JSC::ArrayPatternNode::bindValue const):

• inspector/JSInjectedScriptHost.cpp:

(Inspector::JSInjectedScriptHost::iteratorEntries):

• runtime/IteratorOperations.cpp:

(JSC::iteratorNext):
(JSC::iteratorStep):
(JSC::iteratorClose):
(JSC::iteratorForIterable):

• runtime/IteratorOperations.h:

(JSC::forEachInIterable):

• runtime/JSGenericTypedArrayViewConstructorInlines.h:

(JSC::constructGenericTypedArrayViewFromIterator):
(JSC::constructGenericTypedArrayViewWithArguments):

LayoutTests:

Change test to match the new iteration behavior.

• js/sequence-iterator-protocol-2-expected.txt:
• js/sequence-iterator-protocol-2.html:

File:

• trunk/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp (modified) (3 diffs)

trunk/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp

@@ -3945 +3945 @@
         generator.emitCall(iterator.get(), iterator.get(), NoExpectedFunction, args, divot(), divotStart(), divotEnd(), DebuggableCall::No);
     }
+    RefPtr<RegisterID> nextMethod = generator.emitGetById(generator.newTemporary(), iterator.get(), generator.propertyNames().next);
 
     if (m_targetPatterns.isEmpty()) {
@@ -3963 +3964 @@
 
             RefPtr<RegisterID> value = generator.newTemporary();
-            generator.emitIteratorNext(value.get(), iterator.get(), this);
+            generator.emitIteratorNext(value.get(), nextMethod.get(), iterator.get(), this);
             generator.emitGetById(done.get(), value.get(), generator.propertyNames().done);
             generator.emitJumpIfTrue(done.get(), iterationSkipped.get());
@@ -3999 +4000 @@
 
             RefPtr<RegisterID> value = generator.newTemporary();
-            generator.emitIteratorNext(value.get(), iterator.get(), this);
+            generator.emitIteratorNext(value.get(), nextMethod.get(), iterator.get(), this);
             generator.emitGetById(done.get(), value.get(), generator.propertyNames().done);
             generator.emitJumpIfTrue(done.get(), iterationDone.get());