Re: [PATCH 3/3][DejaGNU] target: Wrap linker flags into `-largs'/`-margs' for Ada

[Maciej Rozycki]

On Thu, 16 May 2019, Jacob Bachmeyer wrote:

> >  I suspect the origins may be different, however as valuable as your 
> > observation is functional problems have precedence over issues with code 
> > structuring, so we need to fix the problem at hand first.  I'm sure 
> > DejaGNU maintainers will be happy to review your implementation of code 
> > restructuring afterwards.
> 
> My concern is that your patch may only solve a small part of the problem 
> -- enough to make your specific case work, yes, but then someone else 
> will hit other parts of the problem later and we spiral towards "tissue 
> of hacks" unmaintainability.

 I think however that fixing problems in small steps as they are 
discovered is also a reasonable approach and a way to move forward: 
perfect is the enemy of good.

 So I don't think the prospect of making a comprehensive solution should 
prevent a simple fix for the problem at hand that has been already 
developed from being applied.

 IOW I don't discourage you from developing a comprehensive solution, 
however applying my proposal right away will help at least some people and 
will not block you in any way.

> The biggest hint to me that your patch is incomplete is that it only 
> adds -largs/-margs to wrap LDFLAGS.  I suspect that there are other 
> -?args options that should be used also with other flag sets, but those 
> do not appear in this patch.  Do we know what the GNU Ada frontend 
> actually expects?

 At first glance it looks to me we should be safe overall as compiler 
flags are supposed to be passed through by `gnatmake' (barring switch 
processing bugs, as observed with 1/3), and IIUC assembler flags are 
considered compiler flags for the purpose of this consideration as 
`gnatmake' does not make assembly a separate build stage.  So while we 
could wrap compiler flags into `-cargs'/`-margs', it would only serve to 
avoid possible `gnatmake' switch processing bugs.

 There's also `-bargs' for binder switches, but I can't see any use for it 
here.

 Finally boards are offered the choice of `adaflags', `cflags', 
`cxxflags', etc. for the individual languages, where the correct syntax 
can be used if anything unusual is needed beyond what I have noted above.

 I'll defer any further consideration to the Ada maintainers cc-ed; I do 
hope I haven't missed anything here, but then Ada is far from being my 
primary area of experience.

> >  The ordering rules are system-specific I'm afraid and we have to be 
> > careful not to break working systems out there.  People may be forced to a 
> > DejaGNU upgrate, due to a newer version of a program being tested having 
> > such a requirement, and can legitimately expect their system to continue 
> > working.
> 
> We can start by simply preserving the existing ordering until we know 
> something should change, but the main goal of my previous message was to 
> collect the requirements for a specification for default_target_compile 
> so I can write regression tests (some of which will fail due to known 
> bugs like broken Ada support in our current implementation) before 
> embarking on extensive changes to that procedure.  Improving 
> "target.test" was already on my local TODO list.

 You are welcome to go ahead with your effort as far as I am concerned.

> Unfortunately, people with that particular attitude seem to have 
> acquired outsize influence over the last few years.  I would suspect an 
> organized attack if I were more conspiracy-oriented, but Hanlon's razor 
> strongly suggests that this is simply a consequence of lowering barriers 
> to entry.

 Nod.

  Maciej