[patch][rfc] "alias weak" X "weak alias"

[Rafael Espíndola]

ping

On 23 July 2014 20:05, Rafael Espíndola <rafael.espindola at gmail.com> wrote:
> Rebased patch attached now that we have agreed that the .ll format is
> not stable.
>
> On 5 June 2014 02:33, Duncan P. N. Exon Smith <dexonsmith at apple.com> wrote:
>>
>> On 2014 Jun 3, at 12:42, Rafael Espíndola <rafael.espindola at gmail.com> wrote:
>>
>>> 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
>>> <clang.patch><llvm.patch>
>>
>> This change SGTM -- the alias ordering is unnatural, and given the
>> current grammar, I don't think it makes parsing any easier.  Might
>> be worth pinging llvmdev about it though.
>>
>> Also, it looks to me like you added an extra space in
>> test/CodeGenCXX/extern-c.cpp:
>>
>>> diff --git a/test/CodeGenCXX/extern-c.cpp b/test/CodeGenCXX/extern-c.cpp
>>> index fefb216..3e87d51 100644
>>> --- a/test/CodeGenCXX/extern-c.cpp
>>> +++ b/test/CodeGenCXX/extern-c.cpp
>>> @@ -59,10 +59,10 @@ extern "C" {
>>>
>>>    // CHECK-NOT: @unused
>>>    // CHECK-NOT: @duplicate_internal
>>> -  // CHECK: @internal_var = alias internal i32* @_Z12internal_var
>>> +  // CHECK: @internal_var =  internal alias i32* @_Z12internal_var
>>
>> here ~~~~~~~~~~~~~~~~~~~~~~~~~~^
>>
>>>    // CHECK-NOT: @unused
>>>    // CHECK-NOT: @duplicate_internal
>>> -  // CHECK: @internal_fn = alias internal i32 ()* @_Z11internal_fnv
>>> +  // CHECK: @internal_fn = internal alias i32 ()* @_Z11internal_fnv
>>>    // CHECK-NOT: @unused
>>>    // CHECK-NOT: @duplicate_internal
>>>  }
>>>
>>