Re: gnat-2017 - ZFP add tasking support

[alby.gamper@gmail.com]

On Monday, June 26, 2017 at 11:35:38 PM UTC+10, Mark Lorenzen wrote:
> On Monday, June 26, 2017 at 12:20:49 PM UTC+2, alby....@gmail.com wrote:
> > On Monday, June 26, 2017 at 5:56:18 PM UTC+10, Mark Lorenzen wrote:
> > > On Monday, June 26, 2017 at 3:20:22 AM UTC+2, alby....@gmail.com wrote:
> > > > I was pleasantly surprised that the recent distribution of gnat-2017 (GPL)
> > > > included a ZFP for native platforms (mine is windows x86). And the project(s)
> > > > compiled cleanly, even on my personal x64 gnat build
> > > > 
> > > > Using this ZFP, along with my WinRT/UWP library, I was a able to build a
> > > > simple Hello World (XAML based) that now PASSES the "Windows Store app Certification". Note this is a true blue native Windows Store app, and does
> > > > NOT use the bridging/Centennial technology.
> > > > 
> > > > The main caveat in all this is, the use of the ZFP which is fairly
> > > > restrictive, and does not allow me to use features of Ada that I feel would be
> > > > a must have running under this environment. In particular "Tasking and maybe
> > > > controlled types"
> > > > 
> > > > Could someone give me guidance on how to add "Tasking" support to the ZFP ?
> > > > I can use the Mingw-64 code base, I assume its not just as simple as adding
> > > > these source files to the ZFP source tree ? Is their any other configuration
> > > > changes needed other than in system.ads ?
> > > > 
> > > > Thanks
> > > > 
> > > > Alex
> > > 
> > > So you want to use the ZERO footprint run-time system, but at the same time you want to use tasks and controlled types? How does this stack up?
> > > 
> > > Why don't you simply use the default run-time system?
> > > 
> > > Regards,
> > > 
> > > Mark L
> > 
> > Hi Mark
> > 
> > Apologies for the slight confusion, what I should have said/meant was that I
> > would like to use the ZFP as a base for a new runtime profile (similar to
> > what AdaCore do for some of their non default run-time systems, such as the
> > various flavours of Ravenscar and high integrity run-time systems)
> > 
> > And yes I could use the default run-time, but in its current form on mingw-64
> > its NOT certified to be distributed via "Windows Store" since it uses parts
> > of the "C/C++" runtime that are not compatible with that environment.
> > 
> > So I have 2 options
> > 
> > 1) Start from the ZFP and add the relevant features such as Tasking
> > or
> > 2) Use the default runtime and strip out all the "Windows Store" functions
> > that are not compatible
> > 
> > I would tend to favour the second approach, but the intent of my original
> > question was to try and determine the amount of effort needed for option 1)
> > 
> > Please note that the central theme of incompatibles with the default run-time
> > and "windows store" are the following
> > 
> > a) Store apps have no notion of a "Console" so "C" functions like printf
> > and family wont work.
> > b) "C" functions such as memcpy, memset are NOT supported in "Windows Store"
> > c) There are some other functions in libgnat to do with exception handling
> > that are also NOT supported in "Windows Store"
> > 
> > I hope this helps in clarifying what I am trying to achieve
> > 
> > Thanks
> > 
> > Alex
> 
> OK that makes sense. I would definately try option 2!
> 
> Try and look in this document for information on restricted run-time systems: http://docs.adacore.com/gnathie_ug-docs/html/gnathie_ug/gnathie_ug.html You should especially check chapter 5.
> 
> Regards,
> 
> Mark L

Hi Mark and Simon

Thanks for your valued advise, Option 2) was a lot easier to implement than I
thought it would be. However in removing the "restricted" functions, and I
believe this centres around the SEH (ie exception handling API's such as
RtlVirtualUnwind and RtlCaptureContext) I have inadvertently screwed up Ada's
exception handling !

I'll try and dig deeper and analyse the issue more deeply, But if anyone could
give me pointers on the SEH code in "raise_gcc.c", "unwind_seh.c" and
"traceback.c", that would be greatly appreciated.

Thanks

Alex