llvm dev - Jun 2014 - [LLVMdev] [rfc] "alias weak" X "weak alias"

moving to llvmdev.

It always amused me that we have

@a = weak global ...
but
@b = alias weak ...

I decided to dig why that is. The best I could find was

http://llvm.org/bugs/show_bug.cgi?id=1017#c15

Looking at some really old cold then suggests that the reason was that
the old bison based parser hard a reduction for alias linkages and
another one for global variable linkages. Putting the alias first
avoided the reduce/reduce conflict.

The days of the old .ll parser are long gone, but is it too late to
change? In case it is not, the attached patches implement just that
:-)

Cheers,
Rafael
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rebased patches attached.

On 5 June 2014 09:51, Rafael Espíndola <rafael.espindola at gmail.com>
wrote:
> moving to llvmdev.
>
> It always amused me that we have
>
> @a = weak global ...
> but
> @b = alias weak ...
>
> I decided to dig why that is. The best I could find was
>
> http://llvm.org/bugs/show_bug.cgi?id=1017#c15
>
> Looking at some really old cold then suggests that the reason was that
> the old bison based parser hard a reduction for alias linkages and
> another one for global variable linkages. Putting the alias first
> avoided the reduce/reduce conflict.
>
> The days of the old .ll parser are long gone, but is it too late to
> change? In case it is not, the attached patches implement just that
> :-)
>
> Cheers,
> Rafael
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> Looking at some really old cold then suggests that the reason was that
> the old bison based parser hard a reduction for alias linkages and
> another one for global variable linkages. Putting the alias first
> avoided the reduce/reduce conflict.
Exactly
> The days of the old .ll parser are long gone, but is it too late to
> change? In case it is not, the attached patches implement just that
> :-)
I'm afraid you need to provide syntax autoupgrade until 4.0

-- 
With best regards, Anton Korobeynikov
Faculty of Mathematics and Mechanics, Saint Petersburg State University

>> The days of the old .ll parser are long gone, but is it too late to
>> change? In case it is not, the attached patches implement just that
>> :-)
> I'm afraid you need to provide syntax autoupgrade until 4.0
Why, we moved to doing autoupgrade via bitcode quiet some time ago.
There were quiet a few format changes to the .ll in the process.

Cheers,
Rafael