release_33 branch: proposing r183297

[Eric Christopher]

I'm fine with merging this change, though I don't think it was in
isolation. Dave should be able to comment on any dependencies.

-eric

On Mon, Jul 8, 2013 at 12:55 PM, Dimitry Andric <dimitry at andric.com> wrote:
> Hi,
>
> For the 3.3 release branch, I would like to propose merging r183297:
>
> r183297 from llvm trunk (by David Blaikie):
>
>   PR15662: Optimized debug info produces out of order function
>   parameters
>
>   When a function is inlined we lazily construct the variables
>   representing the function's parameters. After that, we add any
>   remaining unused parameters.
>
>   If the function doesn't use all the parameters, or uses them out of
>   order, then the DWARF would produce them in that order, producing a
>   parameter order that doesn't match the source.
>
>   This fix causes us to always keep the arg variables at the start of
>   the variable list & in the original order from the source.
>
> On FreeBSD, this enables DTrace to work properly on certain functions compiled with optimization, where previously the debug information had its arguments swapped around.
>
> This commit should apply to the release_33 branch without modification.
>
> -Dimitry
>