[arm] Don't call branch_offset within CheckConstPool.

[arm] Don't call branch_offset within CheckConstPool.

This basically means that we must not use the b(Label*) version here,
but the b(int) version instead to jump over the constant pool.

BUG=v8:4292
LOG=y

Committed: https://crrev.com/879550ce0f8d3cffb519440101a4026635bc6026
Cr-Commit-Position: refs/heads/master@{#29552}

[Benedikt Meurer, 2015-07-09 09:52:33]

bmeurer@chromium.org changed reviewers:
+ rmcilroy@chromium.org, rodolph.perfetta@arm.com

[rmcilroy, 2015-07-09 09:59:51]

On 2015/07/09 09:52:34, Benedikt Meurer wrote:

As discussed offline, let's add a DCHECK in BlockConstPoolFor to ensure it's
never called from within a BlockConstPoolScope. I'll try and think of a way to
repo your bug...

[Benedikt Meurer, 2015-07-09 10:03:46]

On 2015/07/09 09:59:51, rmcilroy wrote:
> On 2015/07/09 09:52:34, Benedikt Meurer wrote:
> 
> As discussed offline, let's add a DCHECK in BlockConstPoolFor to ensure it's
> never called from within a BlockConstPoolScope. I'll try and think of a way to
> repo your bug...

As mentioned by Rodolph offline, BlockConstPoolFor is safe to call within a
BlockConstPoolScope.
The issue is really the call to branch_offset from within CheckConstPool, it
seems.

[rmcilroy, 2015-07-09 10:18:43]

On 2015/07/09 10:03:46, Benedikt Meurer wrote:
> On 2015/07/09 09:59:51, rmcilroy wrote:
> > On 2015/07/09 09:52:34, Benedikt Meurer wrote:
> > 
> > As discussed offline, let's add a DCHECK in BlockConstPoolFor to ensure it's
> > never called from within a BlockConstPoolScope. I'll try and think of a way
to
> > repo your bug...
> 
> As mentioned by Rodolph offline, BlockConstPoolFor is safe to call within a
> BlockConstPoolScope.
> The issue is really the call to branch_offset from within CheckConstPool, it
> seems.

lgtm, thanks!

[Benedikt Meurer, 2015-07-09 10:20:35]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2015-07-09 10:20:40]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1224243002/20001

[commit-bot: I haz the power, 2015-07-09 10:32:28]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-07-09 10:32:40]

Patchset 2 (id:??) landed as
https://crrev.com/879550ce0f8d3cffb519440101a4026635bc6026
Cr-Commit-Position: refs/heads/master@{#29552}