RE: [PATCH 1/5] Fix size of external_reloc for pe-aarch64

[Tamar Christina <Tamar.Christina@arm.com>]

> -----Original Message-----
> From: Jan Beulich <jbeulich@suse.com>
> Sent: Friday, December 16, 2022 7:04 AM
> To: Mark Harmstone <mark@harmstone.com>
> Cc: binutils@sourceware.org; wej22007@outlook.com;
> zac.walker@linaro.org; Tamar Christina <Tamar.Christina@arm.com>
> Subject: Re: [PATCH 1/5] Fix size of external_reloc for pe-aarch64
> 
> On 16.12.2022 03:13, Mark Harmstone wrote:
> > This patch series finishes off the work by Jedidiah Thompson, and adds
> > support for creating aarch64 PE images.
> >
> > This should be essentially complete: I've used this to create a "hello
> > world" Windows program in asm, and (with GCC patches) a UEFI program
> > in C. I think the only things missing are the .secidx relocation,
> > which is needed for PDBs, and the SEH pseudos used for C++ exceptions.
> >
> > This first patch fixes the size of RELSZ; I'm not sure why it was 14
> > in the first place. This is the size of the "Base Relocation Block" in
> > https://learn.microsoft.com/en-us/windows/win32/debug/pe-format, and
> > AFAIK should be 10 for everything.
> 
> Not sure - there look to be different formats in use, judging from other
> headers in include/coff/. See e.g. arm.h which even has two forms.
> Clearly in the original commit (b69c9d41e894), targeting only objcopy (and
> maybe objdump) for PE binaries, this didn't really matter. Does it actually
> matter for you, when you're also only targeting PE? Or are you (in spite of
> the title) really after COFF objects as well?
> 
> Let me Cc Tamar, the author of the original patch, to possibly shed some
> more light on what the struct was initially derived from.

The code was taken from the Arm port which weirdly had a different size
for this whether it was a WINCE target or not.  For WINCE target it has 10, but for
everything else 14 (See include/coff/arm.h).   Since I didn't have relocations
support anyway (the original intention was only to support objcopy workflow)
I didn't dig too deeply into why Arm has it as 14 and the extra field.

That said 10 looks to be the correct value.

Thanks,
Tamar

> 
> Jan