[libav-devel] [GASPP PATCH] Comment out "it" instructions for armasm

Martin Storsjö martin at martin.st
Fri Oct 4 14:37:34 CEST 2019


On Thu, 3 Oct 2019, Martin Storsjö wrote:

> On Thu, 3 Oct 2019, Janne Grunau wrote:
>
>> On 2019-10-02 11:53:28 +0300, Martin Storsjö wrote:
>>> Armasm implicitly adds it instructions as needed. In VS 2019 16.3,
>>> there's a bug [1] in armasm making it fail to parse these it instructions
>>> (but it can still add them implicitly just fine).
>>> 
>>> I'm not sure if it really is worth working around this issue, or just
>>> wait for it to hopefully be fixed by the next release again.
>>> 
>>> [1] 
> https://developercommunity.visualstudio.com/content/problem/757709/armasm-fails-to-handle-it-instructions.html
>>> ---
>>>  gas-preprocessor.pl | 4 ++++
>>>  1 file changed, 4 insertions(+)
>>> 
>>> diff --git a/gas-preprocessor.pl b/gas-preprocessor.pl
>>> index b6c2786..9d8fb5d 100755
>>> --- a/gas-preprocessor.pl
>>> +++ b/gas-preprocessor.pl
>>> @@ -1168,6 +1168,10 @@ sub handle_serialized_line {
>>>          $line =~ s/fmxr/vmsr/;
>>>          $line =~ s/fmrx/vmrs/;
>>>          $line =~ s/fadds/vadd.f32/;
>>> +        # Armasm in VS 2019 16.3 errors out on "it" instructions. But
>>> +        # armasm implicitly adds the necessary it instructions anyway, so 
> we
>>> +        # can just filter it out.
>>> +        $line =~ s/^\s*it[te]*\s+/$comm$&/;
>>>      }
>>>      if ($as_type eq "armasm" and $arch eq "aarch64") {
>>>          # Convert "b.eq" into "beq"
>>
>> I guess ok-ish since armasm can handle implicit it instructions. Do you 
>> have expectation when a fixed version might be released? If it's more 
>> than a couple of weeks I'd say the workaround is worth it.
>
> There's roughly one stable release per 3 months, and the first preview for 
> the next one (16.4) was already posted. In some cases, bugfixes do get 
> into the next release (if deemed urgent enough I guess), but otherwise 
> into current+2. So estimate of fix in a stable release is anywhere between 
> 2 and 5 months maybe.
>
> If I would have caught this in August when the first preview actually 
> containing the new broken armasm was out, it might have been possible to 
> have it fixed sooner...

Pushed both of these now.

// Martin


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