GDC 9 and ARM Cortex-M

[Iain Buclaw]

On Sun, 7 Jul 2019 at 08:25, Timo Sintonen via D.gnu
<d.gnu at puremagic.com> wrote:
>
> My little test program is nearly working now.
> Some funny things I have found:
>
> - When not using -O2 4 extra bytes appear in front of tdata init
> values. With -O2 they disappear.

Don't think that has anything to do with gdc.

> - I have my own calloc where I first allocate a block with malloc
> and then use memset to zero it. GCC can see this and replaces
> these two calls with a call to calloc...
>

Use -fno-builtin to disable C function recognition.

> >
> > There were big changes in exception handling code about 2 years
> > ago and my exception code stopped to work. What was changed
> > back then? How can I get my code to work again? Could this be
> > some struct alignment problem like some years ago?
>
> The program dies somewhere in unwinding code. It looks like the
> stack pointer is moved incorrectly and values are popped to wrong
> registers in function return. There might be a size mismatch
> between c and d side when function arguments are passed in stack.
> Any idea where to look?
>

The only recent change that would have affected ABI is the addition of
the general-regs-only attribute added for ARM EABI.  As far as I still
know - and I have done testing on my phone that sports a Cortex-A53 -
the unwind routines for gdc work well.  I'm not aware of there being
any differences between ARM targets regarding type sizes.

Function and type definitions are in gcc/unwind/arm_commond.d, and
that has been translated from gcc/ginclude/unwind-arm-common.h.

-- 
Iain