Avoid infinite growth of linked hash map implementation

Avoid infinite growth of linked hash map implementation

R=iposva@google.com, koda@google.com

Committed: https://code.google.com/p/dart/source/detail?r=44671

[kustermann, 2015-03-24 16:14:33]

kustermann@google.com changed reviewers:
+ iposva@google.com

[kustermann, 2015-03-24 16:14:33]

The set implementation should be correct.

[Ivan Posva, 2015-03-24 16:24:38]

iposva@google.com changed reviewers:
+ koda@google.com

[Ivan Posva, 2015-03-24 16:24:38]

LGTM -ip

[koda, 2015-03-24 16:27:57]

LGTM, thanks. We should have a test will lots of repeated add/delete. I can add
one.

https://codereview.chromium.org/1005083004/diff/1/dart/runtime/lib/compact_ha...
File dart/runtime/lib/compact_hash.dart (right):

https://codereview.chromium.org/1005083004/diff/1/dart/runtime/lib/compact_ha...
dart/runtime/lib/compact_hash.dart:98: if ((_deletedKeys << 2) > _usedData) {
Perhaps expressing this in terms of 'length' instead would have made the bug
easier to spot:

if (_deletedKeys > length)
...

[kustermann, 2015-03-24 16:32:39]

Committed patchset #1 (id:1) manually as 44671 (presubmit successful).

[kustermann, 2015-03-24 16:44:01]

https://codereview.chromium.org/1005083004/diff/1/dart/runtime/lib/compact_ha...
File dart/runtime/lib/compact_hash.dart (right):

https://codereview.chromium.org/1005083004/diff/1/dart/runtime/lib/compact_ha...
dart/runtime/lib/compact_hash.dart:98: if ((_deletedKeys << 2) > _usedData) {
On 2015/03/24 16:27:57, koda wrote:
> Perhaps expressing this in terms of 'length' instead would have made the bug
> easier to spot:
> 
> if (_deletedKeys > length)
> ...
Good point. Ivan wanted me to submit the CL as is -  sorry for not addressing
the comment - in order to get it cherry-picked to dev channel.

If you'll add a test, I guess you can rename it to length.

You could use the VMOptions setting from our test runner to reduce old space
size. i.e. something like:

$ cat tests/standalone/map_literal_oom_test.dart
// VMOptions=--old_gen_heap_size=10

main() {
  var x = {};
  for (int i = 0; i < 1000000000; i++) {
    x[i] = 10;
    x.remove(i);
  }
}