Dart2js: Fix stack overflow in new String.fromCharCodes bug=6919

sdk/lib/_internal/compiler/implementation/lib/js_helper.dart

Index: sdk/lib/_internal/compiler/implementation/lib/js_helper.dart
diff --git a/sdk/lib/_internal/compiler/implementation/lib/js_helper.dart b/sdk/lib/_internal/compiler/implementation/lib/js_helper.dart
index ea31fe24088f2941034de76a538745bf5acd89e5..7d838f891fecb121f1c7180ee638838f08abae08 100644
--- a/sdk/lib/_internal/compiler/implementation/lib/js_helper.dart
+++ b/sdk/lib/_internal/compiler/implementation/lib/js_helper.dart
@@ -535,7 +535,22 @@ class Primitives {
 
   static num dateNow() => JS('num', r'Date.now()');
 
-  static stringFromCodePoints(codePoints) {
+  // This is to fix http://dartbug.com/6919

[floitsch, 2012/11/26 12:01:28]

Please add a little bit of context, so that you don't need to go to the
issue-tracker.

[erikcorry, 2012/12/03 12:37:24]

Done.

+  static String _doFromCharCode(List<int> array) {

[floitsch, 2012/11/26 12:01:28]

_fromCharCodeApply
?

[erikcorry, 2012/12/03 12:37:24]

Done.

+    String acc = "";

[floitsch, 2012/11/26 12:01:28]

result

[erikcorry, 2012/12/03 12:37:24]

Done.

+    const kMaxApply = 500;
+    int end = array.length;
+    for (var i = 0; i < end; i += kMaxApply) {
+      var subarray = end <= kMaxApply ? array :

[floitsch, 2012/11/26 12:01:28]

nit: I would prefer having an "if" there.

[erikcorry, 2012/12/03 12:37:24]

Done.

+          JS('List<int>', r'array.slice(#, #)',

[sra1, 2012/12/03 16:22:44]

JS('=List', ...)

The result of Array.prototype.slice is a JS Array with no type info.

+             i, i + kMaxApply < end ? i + kMaxApply: end);
+      acc = JS('String', '# + String.fromCharCode.apply(#, #)',
+               acc, null, subarray);
+    }
+    return acc;
+  }
+
+  static String stringFromCodePoints(codePoints) {
     List<int> a = <int>[];
     for (var i in codePoints) {
       if (i is !int) throw new ArgumentError(i);
@@ -548,7 +563,7 @@ class Primitives {
         throw new ArgumentError(i);
       }
     }
-    return JS('String', r'String.fromCharCode.apply(#, #)', null, a);
+    _doFromCharCode(a);
   }
 
   static String stringFromCharCodes(charCodes) {
@@ -557,7 +572,7 @@ class Primitives {
       if (i < 0) throw new ArgumentError(i);
       if (i > 0xffff) return stringFromCodePoints(charCodes);
     }
-    return JS('String', r'String.fromCharCode.apply(#, #)', null, charCodes);
+    _doFromCharCode(a);
   }
 
   static String getTimeZoneName(receiver) {