Changeset 127393 in webkit for trunk/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp

Timestamp:

Sep 2, 2012, 2:27:23 PM (13 years ago)

Author:

[email protected]

Message:

Refactored scope chain opcodes to support optimization for named function expressions
​https://bugs.webkit.org/show_bug.cgi?id=95658

Reviewed by Sam Weinig.

Renamed

push_scope => push_with_scope
push_new_scope => push_name_scope

to clarify the difference between them.

Changed push_with_scope and push_name_scope not to save the new scope in
a temporary register, since doing so made optimization harder.

(The old behavior was a hold-over from when the scope chain wasn't
a GC object, and wouldn't be marked otherwise. Now, the scope chain is
marked because it is a GC object pointed to by the call frame.)

Changed push_name_scope to accept an operand specifying the attributes
for the named property, instead of assuming DontDelete, because a named
function expression needs ReadOnly|DontDelete.

• bytecompiler/BytecodeGenerator.cpp:

(JSC::BytecodeGenerator::highestUsedRegister): Removed this function,
which used to be related to preserving saved scope object temporaries,
because it had no callers.

File:

• trunk/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp (modified) (2 diffs)

trunk/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp

@@ -1757 +1757 @@
 {
     generator.emitDebugHook(WillExecuteStatement, firstLine(), lastLine(), column());
-    
-    RefPtr<RegisterID> scope = generator.newTemporary();
-    generator.emitNode(scope.get(), m_expr); // scope must be protected until popped
+
+    RefPtr<RegisterID> scope = generator.emitNode(m_expr);
     generator.emitExpressionInfo(m_divot, m_expressionLength, 0);
-    generator.emitPushScope(scope.get());
+    generator.emitPushWithScope(scope.get());
     RegisterID* result = generator.emitNode(dst, m_statement);
     generator.emitPopScope();
@@ -1997 +1996 @@
         }
         
-        generator.emitPushNewScope(exceptionRegister.get(), m_exceptionIdent, exceptionRegister.get());
+        generator.emitPushNameScope(m_exceptionIdent, exceptionRegister.get(), DontDelete);
         generator.emitNode(dst, m_catchBlock);
         generator.emitPopScope();