Changeset 228860 in webkit for trunk/Source/JavaScriptCore/dfg/DFGArgumentsUtilities.cpp

Timestamp:

Feb 20, 2018, 10:56:11 PM (7 years ago)

Author:

[email protected]

Message:

DFG::VarargsForwardingPhase should eliminate getting argument length
​https://bugs.webkit.org/show_bug.cgi?id=182959

Reviewed by Keith Miller.

JSTests:

• microbenchmarks/forward-arguments-dont-escape-on-arguments-length.js: Added.

Source/JavaScriptCore:

This patch teaches the DFG VarargsForwardingPhase to not treat
length accesses on Cloned/Direct Arguments objects as escapes.
It teaches this phase to materialize the length in the same
way the ArgumentsEliminationPhase does.

This is around a 0.5-1% speedup on ARES6 on my iMac. It speeds
up the ML subtest by 2-4%.

This patch also extends compileGetArgumentCountIncludingThis to take
a parameter that is the inline call frame to load from (in the case
where the inline call frame is a varargs frame). This allows the
the emitCodeToGetArgumentsArrayLength helper function to just emit
a GetArgumentCountIncludingThis node instead of a GetLocal. If we
emitted a GetLocal, we'd need to rerun CPS rethreading.

• dfg/DFGArgumentsEliminationPhase.cpp:
• dfg/DFGArgumentsUtilities.cpp:

(JSC::DFG::emitCodeToGetArgumentsArrayLength):

• dfg/DFGByteCodeParser.cpp:

(JSC::DFG::ByteCodeParser::getArgumentCount):

• dfg/DFGClobberize.h:

(JSC::DFG::clobberize):

• dfg/DFGNode.h:

(JSC::DFG::Node::argumentsInlineCallFrame):

• dfg/DFGSpeculativeJIT.cpp:

(JSC::DFG::SpeculativeJIT::compileGetArgumentCountIncludingThis):

• dfg/DFGVarargsForwardingPhase.cpp:
• ftl/FTLLowerDFGToB3.cpp:

(JSC::FTL::DFG::LowerDFGToB3::compileGetArgumentCountIncludingThis):

File:

• trunk/Source/JavaScriptCore/dfg/DFGArgumentsUtilities.cpp (modified) (1 diff)

trunk/Source/JavaScriptCore/dfg/DFGArgumentsUtilities.cpp

@@ -92 +92 @@
     }
     
-    Node* argumentCount;
-    if (!inlineCallFrame)
-        argumentCount = insertionSet.insertNode(nodeIndex, SpecInt32Only, GetArgumentCountIncludingThis, origin);
-    else {
-        VirtualRegister argumentCountRegister(inlineCallFrame->stackOffset + CallFrameSlot::argumentCount);
-        
-        argumentCount = insertionSet.insertNode(
-            nodeIndex, SpecInt32Only, GetStack, origin,
-            OpInfo(graph.m_stackAccessData.add(argumentCountRegister, FlushedInt32)));
-    }
+    Node* argumentCount = insertionSet.insertNode(nodeIndex,
+        SpecInt32Only, GetArgumentCountIncludingThis, origin, OpInfo(inlineCallFrame));
 
     Node* result = insertionSet.insertNode(