[arm] Make CEntryStub's handling of triple return values more robust.

[arm] Make CEntryStub's handling of triple return values more robust.

At the moment the code assumes C-function returns the address of the
struct with the values. Unfortunately, the arm ABI does not guarantee that.
After this CL, we do not assume that, and instead just take the value from the stack.

BUG=chromium:611885
LOG=n

Committed: https://crrev.com/ca266e74cdbb53d2dc8a2103f877014888185c7f
Cr-Commit-Position: refs/heads/master@{#36415}

[Jarin, 2016-05-20 14:07:45]

Description was changed from

==========
[arm] Make CEntryStub's handling of triple return values more robust.

At the moment the code assumes C-function returns the address of the
struct with the values. After this CL, we do not assume that, and
instead just take the value from the stack.

BUG=chromium:611885
LOG=n
==========

to

==========
[arm] Make CEntryStub's handling of triple return values more robust.

At the moment the code assumes C-function returns the address of the
struct with the values. After this CL, we do not assume that, and
instead just take the value from the stack.

BUG=chromium:611885
LOG=n
==========

[Jarin, 2016-05-20 14:07:45]

jarin@chromium.org changed reviewers:
+ rmcilroy@chromium.org

[Jarin, 2016-05-20 14:09:06]

Description was changed from

==========
[arm] Make CEntryStub's handling of triple return values more robust.

At the moment the code assumes C-function returns the address of the
struct with the values. After this CL, we do not assume that, and
instead just take the value from the stack.

BUG=chromium:611885
LOG=n
==========

to

==========
[arm] Make CEntryStub's handling of triple return values more robust.

At the moment the code assumes C-function returns the address of the
struct with the values. Unfortunately, the arm ABI does not guarantee that. 
After this CL, we do not assume that, and instead just take the value from the
stack.

BUG=chromium:611885
LOG=n
==========

[Jarin, 2016-05-20 14:13:05]

Could you take a look please? 

Unfortunately, I do not have a repro that would work just with d8. The only way
I could reproduce was to build chromium for android arm, and then run an example
with for-in compiled with turbofan (such as the one below). With this patch
applied, chrome would not crash anymore.

<script>
function f(a) {
  with({}) {}  // This makes sure that Turbofan kicks in.
  for (var x in a) { }
}
for (var i = 0; i < 100000; i++) {
  f([1]);
}
</script>

[rmcilroy, 2016-05-20 14:21:18]

LGTM, thanks for the fix, sorry about the bug!

I had a look at the other ports - Arm64 doesn't have this problem. Mips/Misp64
do use v0, however the MIPS ABI (AFAIKT) does explicitly require that the return
address is passed back in v0 so this is fine (MIPS folks, chime in if you think
differently).

[Jarin, 2016-05-20 14:23:15]

The CQ bit was checked by jarin@chromium.org

[commit-bot: I haz the power, 2016-05-20 14:23:20]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2000713002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/2000713002/1

[commit-bot: I haz the power, 2016-05-20 14:37:00]

Description was changed from

==========
[arm] Make CEntryStub's handling of triple return values more robust.

At the moment the code assumes C-function returns the address of the
struct with the values. Unfortunately, the arm ABI does not guarantee that. 
After this CL, we do not assume that, and instead just take the value from the
stack.

BUG=chromium:611885
LOG=n
==========

to

==========
[arm] Make CEntryStub's handling of triple return values more robust.

At the moment the code assumes C-function returns the address of the
struct with the values. Unfortunately, the arm ABI does not guarantee that. 
After this CL, we do not assume that, and instead just take the value from the
stack.

BUG=chromium:611885
LOG=n
==========

[commit-bot: I haz the power, 2016-05-20 14:37:01]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-05-20 14:38:54]

Description was changed from

==========
[arm] Make CEntryStub's handling of triple return values more robust.

At the moment the code assumes C-function returns the address of the
struct with the values. Unfortunately, the arm ABI does not guarantee that. 
After this CL, we do not assume that, and instead just take the value from the
stack.

BUG=chromium:611885
LOG=n
==========

to

==========
[arm] Make CEntryStub's handling of triple return values more robust.

At the moment the code assumes C-function returns the address of the
struct with the values. Unfortunately, the arm ABI does not guarantee that.
After this CL, we do not assume that, and instead just take the value from the
stack.

BUG=chromium:611885
LOG=n

Committed: https://crrev.com/ca266e74cdbb53d2dc8a2103f877014888185c7f
Cr-Commit-Position: refs/heads/master@{#36415}
==========

[commit-bot: I haz the power, 2016-05-20 14:38:55]

Patchset 1 (id:??) landed as
https://crrev.com/ca266e74cdbb53d2dc8a2103f877014888185c7f
Cr-Commit-Position: refs/heads/master@{#36415}