Changeset 68338 in webkit for trunk/JavaScriptCore/bytecompiler/NodesCodegen.cpp

Timestamp:

Sep 25, 2010, 2:42:00 PM (15 years ago)

Author:

[email protected]

Message:

2010-09-25 Oliver Hunt <​[email protected]>

Reviewed by Cameron Zwarich.

Avoid constructing arguments object when accessing length and index properties
​https://bugs.webkit.org/show_bug.cgi?id=46572

Add opcodes to read argument length and properties, and then implement them.
Much like other lazy opcodes these opcodes take a fast path when the arguments
object has not been instantiated, and fall back on generic access mechanisms
if they are acting on an instantiated object.

3% win on v8-earleyboyer, no change elsewhere.

• bytecode/CodeBlock.cpp: (JSC::CodeBlock::dump):
• bytecode/Opcode.h:
• bytecompiler/BytecodeGenerator.cpp: (JSC::BytecodeGenerator::emitGetArgumentsLength): (JSC::BytecodeGenerator::emitGetArgumentByVal):
• bytecompiler/BytecodeGenerator.h:
• bytecompiler/NodesCodegen.cpp: (JSC::BracketAccessorNode::emitBytecode): (JSC::DotAccessorNode::emitBytecode):
• interpreter/Interpreter.cpp: (JSC::Interpreter::privateExecute):
• jit/JIT.cpp: (JSC::JIT::privateCompileMainPass): (JSC::JIT::privateCompileSlowCases):
• jit/JIT.h:
• jit/JITOpcodes.cpp: (JSC::JIT::emit_op_get_arguments_length): (JSC::JIT::emitSlow_op_get_arguments_length): (JSC::JIT::emit_op_get_argument_by_val): (JSC::JIT::emitSlow_op_get_argument_by_val):
• jit/JITOpcodes32_64.cpp: (JSC::JIT::emit_op_get_arguments_length): (JSC::JIT::emitSlow_op_get_arguments_length): (JSC::JIT::emit_op_get_argument_by_val): (JSC::JIT::emitSlow_op_get_argument_by_val):

File:

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

trunk/JavaScriptCore/bytecompiler/NodesCodegen.cpp

@@ -291 +291 @@
 RegisterID* BracketAccessorNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
+    if (m_base->isResolveNode() && generator.willResolveToArguments(static_cast<ResolveNode*>(m_base)->identifier())) {
+        RegisterID* property = generator.emitNode(m_subscript);
+        generator.emitExpressionInfo(divot(), startOffset(), endOffset());    
+        return generator.emitGetArgumentByVal(generator.finalDestination(dst), generator.uncheckedRegisterForArguments(), property);
+    }
+
     RefPtr<RegisterID> base = generator.emitNodeForLeftHandSide(m_base, m_subscriptHasAssignments, m_subscript->isPure(generator));
     RegisterID* property = generator.emitNode(m_subscript);
@@ -301 +307 @@
 RegisterID* DotAccessorNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
+    if (m_ident == generator.propertyNames().length) {
+        if (!m_base->isResolveNode())
+            goto nonArgumentsPath;
+        ResolveNode* resolveNode = static_cast<ResolveNode*>(m_base);
+        if (!generator.willResolveToArguments(resolveNode->identifier()))
+            goto nonArgumentsPath;
+        generator.emitExpressionInfo(divot(), startOffset(), endOffset());    
+        return generator.emitGetArgumentsLength(generator.finalDestination(dst), generator.uncheckedRegisterForArguments());
+    }
+
+nonArgumentsPath:
     RegisterID* base = generator.emitNode(m_base);
     generator.emitExpressionInfo(divot(), startOffset(), endOffset());