[wasm] Fix checking of unreachable code (clear stack after unreachable).

[wasm] Fix checking of unreachable code (clear stack after unreachable).

R=rossberg@chromium.org
BUG=chromium:682659
Review-Url: https://codereview.chromium.org/2638383004
Cr-Commit-Position: refs/heads/master@{#42502}
Committed: https://chromium.googlesource.com/v8/v8/+/34b337fae6bc7c354ec76ada6e10e21e492492e4

[titzer, 2017-01-19 12:48:46]

The CQ bit was checked by titzer@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-01-19 12:48:54]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[rossberg, 2017-01-19 12:55:11]

lgtm

https://codereview.chromium.org/2638383004/diff/1/src/wasm/function-body-deco...
File src/wasm/function-body-decoder.cc (right):

https://codereview.chromium.org/2638383004/diff/1/src/wasm/function-body-deco...
src/wasm/function-body-decoder.cc:1246: if (control_.empty()) {
I suppose you could avoid spurious case distinctions like this by pushing a
control frame for the function block itself, so that the stack is never empty?

[titzer, 2017-01-19 12:58:17]

On 2017/01/19 12:55:11, rossberg wrote:
> lgtm
> 
>
https://codereview.chromium.org/2638383004/diff/1/src/wasm/function-body-deco...
> File src/wasm/function-body-decoder.cc (right):
> 
>
https://codereview.chromium.org/2638383004/diff/1/src/wasm/function-body-deco...
> src/wasm/function-body-decoder.cc:1246: if (control_.empty()) {
> I suppose you could avoid spurious case distinctions like this by pushing a
> control frame for the function block itself, so that the stack is never empty?

Actually we do push a control frame for it, but this is more defensive
programming. I suppose I could make it a DCHECK.

[commit-bot: I haz the power, 2017-01-19 13:20:41]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-01-19 13:20:42]

Dry run: This issue passed the CQ dry run.

[titzer, 2017-01-19 13:21:59]

The CQ bit was checked by titzer@chromium.org

[commit-bot: I haz the power, 2017-01-19 13:22:02]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-01-19 13:23:57]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1484832119309520, "parent_rev":
"695026d411edcc222e514aa7090a42554237cb2a", "commit_rev":
"34b337fae6bc7c354ec76ada6e10e21e492492e4"}

[commit-bot: I haz the power, 2017-01-19 13:24:03]

Description was changed from

==========
[wasm] Fix checking of unreachable code (clear stack after unreachable).

R=rossberg@chromium.org
BUG=chromium:682659
==========

to

==========
[wasm] Fix checking of unreachable code (clear stack after unreachable).

R=rossberg@chromium.org
BUG=chromium:682659

Review-Url: https://codereview.chromium.org/2638383004
Cr-Commit-Position: refs/heads/master@{#42502}
Committed:
https://chromium.googlesource.com/v8/v8/+/34b337fae6bc7c354ec76ada6e10e21e492...
==========

[commit-bot: I haz the power, 2017-01-19 13:24:04]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/v8/v8/+/34b337fae6bc7c354ec76ada6e10e21e492...