Oilpan: Make sure that vtables for garbage collected mixin objects have

Oilpan: Make sure that vtables for garbage collected mixin objects have
vtable entries for the trace method.

If we get garbage collection during construction of an object with
a virtual trace method we need to make sure that all vtables in
the inheritance hierarchy have entries for the trace method.
Otherwise, we can get out-of-bounds access of a super class vtable.

R=erik.corry@gmail.com, haraken@chromium.org, wibling@chromium.org
BUG=382557
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=178431

[Mads Ager (chromium), 2014-07-18 08:41:27]

+oilpan-reviews

[wibling-chromium, 2014-07-18 08:52:12]

lgtm

[Erik Corry, 2014-07-18 09:05:52]

lgtm

[tkent, 2014-07-18 09:13:39]

lgtm

[Mads Ager (chromium), 2014-07-18 09:27:59]

The CQ bit was checked by ager@chromium.org

[commit-bot: I haz the power, 2014-07-18 09:29:48]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/ager@chromium.org/406523002/1

[haraken, 2014-07-18 09:37:38]

LGTM

[Mads Ager (chromium), 2014-07-18 10:04:54]

The CQ bit was checked by ager@chromium.org

[commit-bot: I haz the power, 2014-07-18 10:05:59]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/ager@chromium.org/406523002/20001

[commit-bot: I haz the power, 2014-07-18 11:12:02]

Change committed as 178431

[zerny-chromium, 2014-07-19 07:21:58]

https://codereview.chromium.org/406523002/diff/20001/Source/platform/Suppleme...
File Source/platform/Supplementable.h (right):

https://codereview.chromium.org/406523002/diff/20001/Source/platform/Suppleme...
Source/platform/Supplementable.h:219: class
GC_PLUGIN_IGNORE("http://crbug.com/395036") HeapSupplementable : public
SupplementableBase<T, true>, public GarbageCollectedMixin {
DBC this ignore is really bad since it will executively disable the plugin
checks for all derived classes too.

https://codereview.chromium.org/406523002/diff/20001/Source/platform/heap/Vis...
File Source/platform/heap/Visitor.h (right):

https://codereview.chromium.org/406523002/diff/20001/Source/platform/heap/Vis...
Source/platform/heap/Visitor.h:589: virtual void adjustAndMark(Visitor*) const {
};
DBC we need to extend the plugin checks (or find a suitable static assert) after
this change since we relied on the pure virtual compiler checks to catch the
error if a mixin did not use the USING... macro.

[zerny-chromium, 2014-07-19 07:23:51]

On 2014/07/19 07:21:58, zerny-chromium wrote:
>
https://codereview.chromium.org/406523002/diff/20001/Source/platform/Suppleme...
> File Source/platform/Supplementable.h (right):
> 
>
https://codereview.chromium.org/406523002/diff/20001/Source/platform/Suppleme...
> Source/platform/Supplementable.h:219: class
> GC_PLUGIN_IGNORE("http://crbug.com/395036") HeapSupplementable : public
> SupplementableBase<T, true>, public GarbageCollectedMixin {
> DBC this ignore is really bad since it will executively disable the plugin
> checks for all derived classes too.
> 
>
https://codereview.chromium.org/406523002/diff/20001/Source/platform/heap/Vis...
> File Source/platform/heap/Visitor.h (right):
> 
>
https://codereview.chromium.org/406523002/diff/20001/Source/platform/heap/Vis...
> Source/platform/heap/Visitor.h:589: virtual void adjustAndMark(Visitor*) const
{
> };
> DBC we need to extend the plugin checks (or find a suitable static assert)
after
> this change since we relied on the pure virtual compiler checks to catch the
> error if a mixin did not use the USING... macro.

s/executively/effectively (swipe fail)

[wibling-chromium, 2014-07-21 08:38:49]

https://codereview.chromium.org/406523002/diff/20001/Source/platform/Suppleme...
File Source/platform/Supplementable.h (right):

https://codereview.chromium.org/406523002/diff/20001/Source/platform/Suppleme...
Source/platform/Supplementable.h:219: class
GC_PLUGIN_IGNORE("http://crbug.com/395036") HeapSupplementable : public
SupplementableBase<T, true>, public GarbageCollectedMixin {
On 2014/07/19 07:21:58, zerny-chromium wrote:
> DBC this ignore is really bad since it will executively disable the plugin
> checks for all derived classes too. 

FYI I am removing this ignore as part of removing off-heap tracing for hashmaps.
See
https://codereview.chromium.org/403333002/diff/1/Source/platform/Supplementab...
for details.