Changeset 39799 in webkit for trunk/JavaScriptCore/interpreter

Timestamp:

Jan 11, 2009, 11:12:47 AM (16 years ago)

Author:

[email protected]

Message:

Bug 23128: get/put_by_val need to respecialise in the face of ByteArray

Reviewed by Darin Adler and Anders Carlsson

Restructure the code slightly, and add comments per Darin's suggestions

File:

• trunk/JavaScriptCore/interpreter/Interpreter.cpp (modified) (4 diffs)

trunk/JavaScriptCore/interpreter/Interpreter.cpp

@@ -5119 +5119 @@
             result = JSValuePtr::encode(asString(baseValue)->getIndex(ARG_globalData, i));
         else if (interpreter->isJSByteArray(baseValue) && asByteArray(baseValue)->canAccessIndex(i)) {
+            // All fast byte array accesses are safe from exceptions so return immediately to avoid exception checks.
             ctiPatchCallByReturnAddress(STUB_RETURN_ADDRESS, reinterpret_cast<void*>(cti_op_get_by_val_byte_array));
             return JSValuePtr::encode(asByteArray(baseValue)->getIndex(i));
@@ -5147 +5148 @@
     bool isUInt32 = JSImmediate::getUInt32(subscript, i);
     if (LIKELY(isUInt32)) {
-        if (interpreter->isJSByteArray(baseValue) && asByteArray(baseValue)->canAccessIndex(i))
+        if (interpreter->isJSByteArray(baseValue) && asByteArray(baseValue)->canAccessIndex(i)) {
+            // All fast byte array accesses are safe from exceptions so return immediately to avoid exception checks.
             return JSValuePtr::encode(asByteArray(baseValue)->getIndex(i));
-        else {
-            result = baseValue->get(callFrame, i);
-            if (!interpreter->isJSByteArray(baseValue))
-                ctiPatchCallByReturnAddress(STUB_RETURN_ADDRESS, reinterpret_cast<void*>(cti_op_get_by_val));
-        }
+        }
+
+        result = baseValue->get(callFrame, i);
+        if (!interpreter->isJSByteArray(baseValue))
+            ctiPatchCallByReturnAddress(STUB_RETURN_ADDRESS, reinterpret_cast<void*>(cti_op_get_by_val));
     } else {
         Identifier property(callFrame, subscript->toString(callFrame));
@@ -5246 +5248 @@
         } else if (interpreter->isJSByteArray(baseValue) && asByteArray(baseValue)->canAccessIndex(i)) {
             JSByteArray* jsByteArray = asByteArray(baseValue);
-            double dValue = 0;
             ctiPatchCallByReturnAddress(STUB_RETURN_ADDRESS, reinterpret_cast<void*>(cti_op_put_by_val_byte_array));
+            // All fast byte array accesses are safe from exceptions so return immediately to avoid exception checks.
             if (JSImmediate::isNumber(value)) {
                 jsByteArray->setIndex(i, JSImmediate::getTruncatedInt32(value));
                 return;
-            } else if (fastIsNumber(value, dValue)) {
-                jsByteArray->setIndex(i, dValue);
-                return;
-            } else
-                baseValue->put(callFrame, i, value);
+            } else {
+                double dValue = 0;
+                if (fastIsNumber(value, dValue)) {
+                    jsByteArray->setIndex(i, dValue);
+                    return;
+                }
+            }
+
+            baseValue->put(callFrame, i, value);
         } else
             baseValue->put(callFrame, i, value);
@@ -5312 +5318 @@
         if (interpreter->isJSByteArray(baseValue) && asByteArray(baseValue)->canAccessIndex(i)) {
             JSByteArray* jsByteArray = asByteArray(baseValue);
-            double dValue = 0;
+            
+            // All fast byte array accesses are safe from exceptions so return immediately to avoid exception checks.
             if (JSImmediate::isNumber(value)) {
                 jsByteArray->setIndex(i, JSImmediate::getTruncatedInt32(value));
                 return;
-            } else if (fastIsNumber(value, dValue)) {
-                jsByteArray->setIndex(i, dValue);
-                return;
-            } else
-                baseValue->put(callFrame, i, value);
-        } else {
-            if (!interpreter->isJSByteArray(baseValue))
-                ctiPatchCallByReturnAddress(STUB_RETURN_ADDRESS, reinterpret_cast<void*>(cti_op_put_by_val));
-            baseValue->put(callFrame, i, value);
-        }
+            } else {
+                double dValue = 0;                
+                if (fastIsNumber(value, dValue)) {
+                    jsByteArray->setIndex(i, dValue);
+                    return;
+                }
+            }
+        }
+
+        if (!interpreter->isJSByteArray(baseValue))
+            ctiPatchCallByReturnAddress(STUB_RETURN_ADDRESS, reinterpret_cast<void*>(cti_op_put_by_val));
+        baseValue->put(callFrame, i, value);
     } else {
         Identifier property(callFrame, subscript->toString(callFrame));