Reviewers: Michael Starzinger,
Description:
Change nonsensical SmartMove no-op behavior to match SimpleMove
The previous behavior, which caused Array.prototype.unshift() (with no args)
to have side-effects, is not spec-compliant nor web-compatible.
This is a baby step towards getting rid of SmartMove; it isolates the test
change in this patch, instead of lumping it in confusingly with all the
other test updates necessary for moving away from SmartMove.
Please review this at https://codereview.chromium.org/666883009/
Base URL: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files (+13, -15 lines):
M src/array.js
M test/mjsunit/array-unshift.js
Index: src/array.js
diff --git a/src/array.js b/src/array.js
index
9e83d979e09b5f31c034cc457a32d62d809e0b15..585d1da8427507f0ef0ea3cb12470d3c9bc21488
100644
--- a/src/array.js
+++ b/src/array.js
@@ -234,6 +234,8 @@ function SmartSlice(array, start_i, del_count, len,
deleted_elements) {
// This function implements the optimized splice implementation that can
use
// special array operations to handle sparse arrays in a sensible fashion.
function SmartMove(array, start_i, del_count, len, num_additional_args) {
+ // Bail out if no moving is necessary.
+ if (num_additional_args === del_count) return;
// Move data to new array.
var new_array = new InternalArray(len - del_count + num_additional_args);
var indices = %GetArrayKeys(array, len);
Index: test/mjsunit/array-unshift.js
diff --git a/test/mjsunit/array-unshift.js b/test/mjsunit/array-unshift.js
index
0eb299a0cee2a145396c2e7036d2237667c256c7..50aab4f52a4b58a316053604c719d4465c48be9a
100644
--- a/test/mjsunit/array-unshift.js
+++ b/test/mjsunit/array-unshift.js
@@ -37,9 +37,7 @@
})();
-// Check that unshift with no args has a side-effect of
-// filling the holes with elements from the prototype
-// (if present, of course)
+// Check that unshift with no args has no side-effects.
(function() {
var len = 3;
var array = new Array(len);
@@ -65,15 +63,15 @@
assertTrue(delete Array.prototype[0]);
assertTrue(delete Array.prototype[2]);
- // unshift makes array own 0 and 2...
- assertTrue(array.hasOwnProperty(0));
+ // array still owns nothing...
+ assertFalse(array.hasOwnProperty(0));
assertFalse(array.hasOwnProperty(1));
- assertTrue(array.hasOwnProperty(2));
+ assertFalse(array.hasOwnProperty(2));
// ... so they are not affected be delete.
- assertEquals(array[0], at0);
+ assertEquals(array[0], undefined);
assertEquals(array[1], undefined);
- assertEquals(array[2], at2);
+ assertEquals(array[2], undefined);
})();
@@ -115,9 +113,7 @@
assertTrue(delete Array.prototype[7]);
})();
-// Check that unshift with no args has a side-effect of
-// filling the holes with elements from the prototype
-// (if present, of course)
+// Check that unshift with no args has no side-effects.
(function() {
var len = 3;
var array = new Array(len);
@@ -142,12 +138,12 @@
assertEquals(len, array.unshift());
- // unshift makes array own 0 and 2...
- assertTrue(array.hasOwnProperty(0));
+ // array still owns nothing.
+ assertFalse(array.hasOwnProperty(0));
assertFalse(array.hasOwnProperty(1));
- assertTrue(array.hasOwnProperty(2));
+ assertFalse(array.hasOwnProperty(2));
- // ... so they are not affected be delete.
+ // ... but still sees values from array_proto.
assertEquals(array[0], at0);
assertEquals(array[1], undefined);
assertEquals(array[2], at2);
--
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