Re: [edk2-devel] Progress on getting Uncrustify working for EDK2?

["Andrew Fish" <afish@apple.com>]

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> On Oct 7, 2021, at 1:43 PM, Marvin Häuser <mhaeuser@posteo.de> wrote:
> 
> Hey Mike,
> Hey Andrew,
> 
> I'll just reply to both mails at once :)
> 
> On 07/10/2021 19:36, Andrew Fish wrote:
>> 
>> 
>>> On Oct 7, 2021, at 1:19 PM, Michael D Kinney <michael.d.kinney@intel.com> wrote:
>>> 
>>> Hi Marvin,
>>> 
>>> Some comments below.
>>> 
>>> Mike
>>> 
>>>> -----Original Message-----
>>>> From:devel@edk2.groups.io<devel@edk2.groups.io> On Behalf Of Marvin Häuser
>>>> Sent: Thursday, October 7, 2021 11:31 AM
>>>> To: Leif Lindholm <leif@nuviainc.com>;devel@edk2.groups.io;mikuback@linux.microsoft.com
>>>> Cc:rebecca@nuviainc.com; Michael Kubacki <Michael.Kubacki@microsoft.com>; Bret Barkelew <Bret.Barkelew@microsoft.com>;
>>>> Kinney, Michael D <michael.d.kinney@intel.com>
>>>> Subject: Re: [edk2-devel] Progress on getting Uncrustify working for EDK2?
>>>> 
>>>> Good day,
>>>> 
>>>> +1, but while you're at it, can we have arguments not align to the
>>>> function name...
>>>> 
>>>>   Status = Test (
>>>>              a
>>>>              );
>>>> 
>>>> ... but to the next natural indentation level?
>>>> 
>>>>   Status = Test (
>>>>     a
>>>>     );
>>>> 
>>>> Basically no IDE I have seen supports EDK II's style, and I wouldn't be
>>>> keen on writing known-broken style to then rely on Uncrustify to fix it.
>>>> 
>>>> I also have heard some controversy regarding casts off-list, where some
>>>> prefer no spaces after casts to stress the evaluation order, and some
>>>> prefer spaces to have clearer visuals (as a cast *ideally* would be
>>>> something rare that requires good justification). Just throwing that out
>>>> there.
>>>> 
>>>> 
>>>> For things unrelated to autoformat (so semi-offtopic) but still relevant
>>>> to the coding spec:
>>>> 
>>>> 1. Allow STATIC functions (if the debugging concerns are still relevant,
>>>> there could be another level of indirection, like RELEASE_STATIC)?
>>> 
>>> Debugging concerns are no longer relevant.  The suggestion in the BZ below
>>> is to remove the STATIC macro and allow EDK II sources to add 'static'
>>> to any functions it makes sense to use on.
>>> 
>>> https://bugzilla.tianocore.org/show_bug.cgi?id=1766
> 
> Thanks! I'd keep STATIC actually just for the sake of not doing no-op changes that do not really do anything and for consistency with CONST, but whatever works really.
> 
>>> 
>>>> 
>>>> 2. Allow variable assignments on definition (basically non-static CONST
>>>> variables are banned...)?
>>> 
>>> Are referring to use of pre-initialized CONST variables declared within
>>> a function?  I think Bret brought this topic up when implementing some
>>> unit tests and the suggestion to pass ECCC was to promote them to
>>> pre-initialized CONST global variables.
> 
> Yes.
> 
>>> 
>>> The challenges we have seen in the past with pre-initialized variables within
>>> a function is that they can cause compilers to inject use of memcpy() calls,
>>> especially if the variable being initialized on the stack is a structure.
>>> These cause build breaks today.
>> 
>> This issue is independent of CONST. I’m not sure a coding style tool is smart enough to catch this generically? You need an understanding of C types to know if the local variable assignment is going to trigger a memcpy().
>> 
>> What I’ve seen in the real world is the firmware compiles with -Os or LTO to fit int he ROM for DEBUG and RELEASE, and the optimizer optimizes away the call to memcpy. Then if you try to build NOOPT (or over ride the compiler flags on an individual driver/lib) you fail to link as only the NOOPT build injects the memcpy.
> 
> +1
> 
>> 
>> Thus I think the best way to enforce this rule is to compile a project NOOPT. I’m trying to remember are there flags to built to tell it to compile and skip the FD construction? Maybe we should advocate platforms add a NOOPT build target that just compiles the code, but does not create the FD?
> 
> I know there were stability concerns with intrinsics in the past, but memcpy() is in the standard, and the rest remained stable to my knowledge. Maybe it's time to fix the issues at the root? Works for us:
> https://github.com/acidanthera/OpenCorePkg/tree/master/Library/OcCompilerIntrinsicsLib <https://github.com/acidanthera/OpenCorePkg/tree/master/Library/OcCompilerIntrinsicsLib>
> 

Marvin,

Good point. This would make the rule moot. So maybe just removing the requirement would be the easiest long term fix. 

Other embedded projects I know of do this too, and as you point out the compilers keep these APIs standard for folks the provide their own runtimes.

Thanks,

Andrew Fish

> Best regards,
> Marvin
> 
>> 
>> Thanks,
>> 
>> Andrew Fish
>> 
>>> 
>>>> 
>>>> 3. Allow variable declarations at any scope (I had some nasty shadowing
>>>> bugs before, probably prohibit shadowing with warnings)?
>>> 
>>> By shadowing do you mean the declaration of the same variable name in
>>> multiple scoped within the same function?
>>> 
>>>> 
>>>> 4. Require that exactly all function declarations and all function
>>>> definitions with no prior declaration must be documented (first
>>>> direction is enforcing docs, second is prohibiting doc duplication, I've
>>>> seen them go out-of-sync plenty of times)?
>>> 
>>> I agree that this can reduce duplication and sync issues.  The uncrustify
>>> tool being discussed here could not help clean this up or enforce this
>>> type of rule.  It is a good topic, but may need to be split out into its
>>> own thread.
>>> 
>>>> 
>>>> The latter bunch would not require any autoformat rules or reformatation
>>>> of existing code, but would be target only new submissions in my
>>>> opinion. Thoughts?
>>>> 
>>>> 
>>>> Thanks for your efforts!
>>>> 
>>>> Best regards,
>>>> Marvin
>>>> 
>>>> 
>>>> Am 07.10.2021 um 12:48 schrieb Leif Lindholm:
>>>>> Hi Michael,
>>>>> 
>>>>> Apologies, I've owed you a response (promised off-list) for a while
>>>>> now.
>>>>> 
>>>>> First, let me say I hugely appreciate this effort. Apart from aligning
>>>>> the codebase(s), this will reduce manual reviewing effort
>>>>> substantially, as well as cutting down on number of rework cycles for
>>>>> developers.
>>>>> 
>>>>> Looking at the changes to (well, the comments in) uncrustify, this
>>>>> seems to be constrained to:
>>>>> - Newline after '(' for multi-line function calls.
>>>>> - Dealing with "(("/"))" for DEBUG macros.
>>>>> - Function pointer typedefs:
>>>>>   - typedef\nEFIAPI
>>>>>   - closing parentheses indentation
>>>>> 
>>>>> I don't think I've made any secret over the years that I am not a
>>>>> massive fan of the EDK2 coding style in general. So I think for any
>>>>> of its quirks that are substantial enough that they require not just
>>>>> custom configuration but actual new function added to existing code
>>>>> conformance tools, this would be an excellent point to sanitise the
>>>>> coding style instead.
>>>>> 
>>>>> Taking these in order:
>>>>> 
>>>>> Newline after '('
>>>>> -----------------
>>>>> I think we already reached a level of flexibility around this, where
>>>>> we don't actually enforce this (or single argument per
>>>>> line). Personally, I'd be happy to update the coding style as
>>>>> required instead.
>>>>> 
>>>>> DEBUG macro parentheses
>>>>> -----------------------
>>>>> How does uncrustify treat DEBUG macros without this modification?
>>>>> Do we start getting everything turned into multi-level indented
>>>>> multi-line statements without this change?
>>>>> 
>>>>> Function pointer typedefs:
>>>>> --------------------------
>>>>> I don't see that function pointer typedefs need to rigidly follow the
>>>>> same pattern as the declaration of functions implementing them. Could
>>>>> we update the coding style (if needed) instead?
>>>>> 
>>>>> Best Regards,
>>>>> 
>>>>> Leif
>>>>> 
>>>>> On Mon, Aug 16, 2021 at 16:00:38 -0400, Michael Kubacki wrote:
>>>>>> The edk2 branch was created here:
>>>>>> https://github.com/makubacki/edk2/tree/uncrustify_poc_2
>>>>>> 
>>>>>> We have a Project Mu fork with custom changes to the Uncrustify tool to help
>>>>>> comply with EDK II formatting here:
>>>>>> https://dev.azure.com/projectmu/_git/Uncrustify
>>>>>> 
>>>>>> The latest information about the status and how to experiment with the
>>>>>> configuration file and the tool are in that fork:
>>>> https://dev.azure.com/projectmu/Uncrustify/_wiki/wikis/Uncrustify.wiki/1/Project-Mu-(EDK-II)-Fork-Readme
>>>>>> 
>>>>>> That said, I have also finished a CI plugin to run Uncrustify that should be
>>>>>> ready soon to initially deploy in Project Mu. Before doing so, I am trying
>>>>>> to settle on an initial configuration file that less strictly but more
>>>>>> reliably formats the code than in the examples in those branches. For
>>>>>> example, remove heuristics that when run against the same set of code
>>>>>> multiple times can produce different results. An example would be a rule
>>>>>> that reformats code because it exceeds a specified column width on one run
>>>>>> but on the next run that reformatted code triggers a different rule to
>>>>>> further align the code and so on. At least initially, some rules might be
>>>>>> tweaked in a more conservative approach that can be tightened in the future.
>>>>>> Once this configuration file is ready, we will baseline Project Mu code as
>>>>>> an example and turn on the plugin. The CI plugin runs Uncrustify against
>>>>>> modified files and if there's any changes, indicating a formatting
>>>>>> deviation, the diff chunks are saved in a log so they can be viewed as a
>>>>>> build artifact.
>>>>>> 
>>>>>> I am making progress on the updated config file and I should be able to post
>>>>>> a "uncrustify_poc_3" branch soon with the results.
>>>>>> 
>>>>>> Regarding indentation, Marvin is right that Uncrustify cannot support edk2
>>>>>> indentation style out-of-box. Some changes are made in that fork to handle
>>>>>> the formatting. At this point, it can handle the indentation in the cases
>>>>>> I've seen. Uncrustify does potentially give us the ability to massively
>>>>>> deploy changes across the codebase in case a decision were made to change
>>>>>> the style.
>>>>>> 
>>>>>> Thanks,
>>>>>> Michael
>>>>>> 
>>>>>> On 8/16/2021 3:39 PM, Marvin Häuser wrote:
>>>>>>> Hey Rebecca,
>>>>>>> 
>>>>>>> I think even Uncrustify has issues with the EDK II indentation style.
>>>>>>> You might want to check the UEFI Talkbox Discord server, I had a brief
>>>>>>> chat with Michael about it there. I don't think realistically any tool
>>>>>>> supports EDK II's indentation style however, so I'd propose it is
>>>>>>> changed. This could be for new submissions only, or actually the entire
>>>>>>> codebase could be reformatted at once with a good tool setup. While this
>>>>>>> screws with git blame, the (to my understanding) decided on CRLF -> LF
>>>>>>> change does that anyway, so at least two evils could be dealt with in
>>>>>>> one go really.
>>>>>>> 
>>>>>>> Best regards,
>>>>>>> Marvin
>>>>>>> 
>>>>>>> On 16/08/2021 21:34, Rebecca Cran wrote:
>>>>>>>> 
>>>>>>>> cc devel@ .
>>>>>>>> 
>>>>>>>> On 8/16/21 1:33 PM, Rebecca Cran wrote:
>>>>>>>>> 
>>>>>>>>> I noticed a message on Twitter about an idea of using Uncrustify
>>>>>>>>> for EDK2 instead of the ECC tool, and came across https://www.mail-
>>>> archive.com/search?l=devel@edk2.groups.io&q=subject:%22Re%5C%3A+%5C%5Bedk2%5C-
>>>> devel%5C%5D+TianoCore+Community+Meeting+Minutes+%5C-+2%5C%2F4%22&o=newest&f=1
>>>>>>>>> .
>>>>>>>>> 
>>>>>>>>> I was wondering if there's been any progress on it that I could
>>>>>>>>> check out?
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> Michael Kubacki: in that message, you said:
>>>>>>>>> 
>>>>>>>>> "I'm planning to put up a branch that we can use as a reference
>>>>>>>>> for a conversation around uncrustify in the next couple of
>>>>>>>>> weeks."
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> Did you end up creating that branch, and if so could you provide
>>>>>>>>> a link to it please?
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> --
>>>>>>>>> Rebecca Cran
>>>>>>>>> 
>>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>> 
>>> 
>>> 
>>> 


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