Changeset 43854 in webkit for trunk/JavaScriptCore/jit/JITStubs.cpp

Timestamp:

May 18, 2009, 10:39:07 PM (16 years ago)

Author:

[email protected]

Message:

2009-05-18 Maciej Stachowiak <​[email protected]>

Reviewed by Oliver Hunt.

• tighten up the code for the load_varargs stub

~1-2% on v8-raytrace

• jit/JITStubs.cpp: (JSC::JITStubs::cti_op_load_varargs): Hoist some loop invariants that the compiler didn't feel like hoisting for us. Remove unneeded exception check.

File:

• trunk/JavaScriptCore/jit/JITStubs.cpp (modified) (2 diffs)

trunk/JavaScriptCore/jit/JITStubs.cpp

@@ -1596 +1596 @@
         int32_t expectedParams = asFunction(callFrame[RegisterFile::Callee].jsValue())->body()->parameterCount();
         int32_t inplaceArgs = min(providedParams, expectedParams);
-        int32_t i = 0;
-        Register* argStore = callFrame->registers() + argsOffset;
         
+        Register* inplaceArgsDst = callFrame->registers() + argsOffset;
+
+        Register* inplaceArgsEnd = inplaceArgsDst + inplaceArgs;
+        Register* inplaceArgsEnd2 = inplaceArgsDst + providedParams;
+
+        Register* inplaceArgsSrc = callFrame->registers() - RegisterFile::CallFrameHeaderSize - expectedParams;
+        Register* inplaceArgsSrc2 = inplaceArgsSrc - providedParams - 1 + inplaceArgs;
+ 
         // First step is to copy the "expected" parameters from their normal location relative to the callframe
-        for (; i < inplaceArgs; i++)
-            argStore[i] = callFrame->registers()[i - RegisterFile::CallFrameHeaderSize - expectedParams];
+        while (inplaceArgsDst < inplaceArgsEnd)
+            *inplaceArgsDst++ = *inplaceArgsSrc++;
+
         // Then we copy any additional arguments that may be further up the stack ('-1' to account for 'this')
-        for (; i < providedParams; i++)
-            argStore[i] = callFrame->registers()[i - RegisterFile::CallFrameHeaderSize - expectedParams - providedParams - 1];
+        while (inplaceArgsDst < inplaceArgsEnd2)
+            *inplaceArgsDst++ = *inplaceArgsSrc2++;
+
     } else if (!arguments.isUndefinedOrNull()) {
         if (!arguments.isObject()) {
@@ -1653 +1661 @@
         }
     }
-    CHECK_FOR_EXCEPTION_AT_END();
+
     return argCount + 1;
 }