New version of v8 from bleeding edge at revision 3649

1 files changed, 34 insertions, 14 deletions

diff --git a/src/runtime.js b/src/runtime.js
index 105749a7..ce2f197f 100644
--- a/src/runtime.js
+++ b/src/runtime.js
@@ -114,24 +114,33 @@ function STRICT_EQUALS(x) {
 // ECMA-262, section 11.8.5, page 53. The 'ncr' parameter is used as
 // the result when either (or both) the operands are NaN.
 function COMPARE(x, ncr) {
-  // Fast case for numbers and strings.
-  if (IS_NUMBER(this) && IS_NUMBER(x)) {
-    return %NumberCompare(this, x, ncr);
-  }
-  if (IS_STRING(this) && IS_STRING(x)) {
-    return %StringCompare(this, x);
+  var left;
+
+  // Fast cases for string, numbers and undefined compares.
+  if (IS_STRING(this)) {
+    if (IS_STRING(x)) return %_StringCompare(this, x);
+    if (IS_UNDEFINED(x)) return ncr;
+    left = this;
+  } else if (IS_NUMBER(this)) {
+    if (IS_NUMBER(x)) return %NumberCompare(this, x, ncr);
+    if (IS_UNDEFINED(x)) return ncr;
+    left = this;
+  } else if (IS_UNDEFINED(this)) {
+    return ncr;
+  } else {
+    if (IS_UNDEFINED(x)) return ncr;
+    left = %ToPrimitive(this, NUMBER_HINT);
   }
 
   // Default implementation.
-  var a = %ToPrimitive(this, NUMBER_HINT);
-  var b = %ToPrimitive(x, NUMBER_HINT);
-  if (IS_STRING(a) && IS_STRING(b)) {
-    return %StringCompare(a, b);
+  var right = %ToPrimitive(x, NUMBER_HINT);
+  if (IS_STRING(left) && IS_STRING(right)) {
+    return %_StringCompare(left, right);
   } else {
-    var a_number = %ToNumber(a);
-    var b_number = %ToNumber(b);
-    if (NUMBER_IS_NAN(a_number) || NUMBER_IS_NAN(b_number)) return ncr;
-    return %NumberCompare(a_number, b_number, ncr);
+    var left_number = %ToNumber(left);
+    var right_number = %ToNumber(right);
+    if (NUMBER_IS_NAN(left_number) || NUMBER_IS_NAN(right_number)) return ncr;
+    return %NumberCompare(left_number, right_number, ncr);
   }
 }
 
@@ -468,6 +477,17 @@ function TO_STRING() {
 }
 
 
+// Specialized version of String.charAt. It assumes string as
+// the receiver type and that the index is a number.
+function STRING_CHAR_AT(pos) {
+  var char_code = %_FastCharCodeAt(this, pos);
+  if (!%_IsSmi(char_code)) {
+    return %StringCharAt(this, pos);
+  }
+  return %CharFromCode(char_code);
+}
+
+
 /* -------------------------------------
    - - -   C o n v e r s i o n s   - - -
    -------------------------------------