Fix some leaks in lld's YAML parser

[Pete Cooper via llvm-commits]

Thanks for pinging this.  I’d forgotten about it.

Spoke to Nick in person.  He said he was happy to defer to Lang on this one.

And thanks for your LGTM.  Assuming Lang is ok with it i’ll commit it.

Cheers,
Pete
> On Feb 4, 2016, at 4:53 PM, Rafael Espíndola <rafael.espindola at gmail.com> wrote:
> 
> Nick, any thought on this? It would be awesome to have check-lld asan clean.
> 
> The patch looks good to me in that all that I see is an allocator
> being passed to more places, but I don't know if that was the
> intention.
> 
> Cheers,
> Rafael
> 
> 
> On 26 January 2016 at 10:42, Rafael Espíndola
> <rafael.espindola at gmail.com> wrote:
>> Nick is probably the best reviewer for the yaml code.
>> 
>> Cheers,
>> Rafael
>> 
>> 
>> On 25 January 2016 at 12:34, Pete Cooper <peter_cooper at apple.com> wrote:
>>> Hi Rafael
>>> 
>>> This should fix some of the leaks seen in PR 21466.
>>> 
>>> The cause was the MappingNormalizationHeap struct which was allocating atoms.  In the binary file parser we allocate atoms in the file::allocator() so that we can avoid the free cost later.
>>> 
>>> This patch makes atoms use the file allocator in the YAML parser when needed.
>>> 
>>> Note, this doesn’t fix all the leaks.  There’s still a bunch I’m trying to understand, but its a good start.
>>> 
>>> Thanks
>>> Pete
>>>