Alice Carlotti <alice.carlo...@arm.com> writes:
> On Tue, Apr 29, 2025 at 02:47:21PM +0100, Alice Carlotti wrote:
>> This demonstrates a clear benefit to make the makefile rules automatic. I
>> thought this might be quite tricky, but it turns out to be fairly
>> straightforward.
>
> Actually, it turns out I missed at least one more thing that's needed, so the
> first two patches combined don't even build cleanly. The issue is that
> dependencies on generated files need some mechanism to ensure that the
> generated files are available before their dependants are built during a clean
> build. This means that I can't just delete the dependency
>
> aarch64-builtins.o: aarch64-builtin-iterators.h
>
>
> Many other generated files are currently specified as prerequisites via the
> rule:
> $(ALL_HOST_OBJS) : | $(generated_files)
>
> I think it would make sense to include the backend generated files into this
> variable. Currently some backend files are included, but this is done using
> the variables TM_H, TM_P_H, TM_D_H and TM_RUST_H variables, which looks like a
> misuse of these variables.
>
> The intended meaning/use of the TM_* variables is also unclear. As far as I
> can tell, it looks like they should list the dependencies of the corresponding
> files generated by mkconfig, of which the direct includes are added
> automatically, but this isn't quite consistent with the current values in
> t-aarch64.
Which files are you thinking of when you say that those macros are being
misused, and that the current values in t-aarch64 aren't consistent with
the intended usage? It looks from a quick glance at:
TM_H += $(srcdir)/config/aarch64/aarch64-fusion-pairs.def \
$(srcdir)/config/aarch64/aarch64-tuning-flags.def \
$(srcdir)/config/aarch64/aarch64-option-extensions.def \
$(srcdir)/config/aarch64/aarch64-cores.def \
$(srcdir)/config/aarch64/aarch64-isa-modes.def \
$(srcdir)/config/aarch64/aarch64-arches.def
that aarch64-fusion-pairs.def and aarch64-tuning-flags.def could be put
in TM_P_H instead of TM_H, since they are included via aarch64-protos.h
but not (apparently) via aarch64.h. But the others look correct.
> Another related observation is that aarch64-builtin-iterators.h is missing
> from
> MOSTLYCLEANFILES, so it isn't removed in a clean build. It ought to be
> included, and I think it would be good if we could use the same list (or
> mostly
> the same list) of generated files for both the order-only prerequiste rule and
> in MOSTLYCLEANFILES.
I agree that it would be good for the common subset to be specified once
rather than twice. But generated_files includes things generated by
configure, which shouldn't be removed by "make mostlyclean".
And MOSTLYCLEANFILES includes .cc files, which shouldn't be
included in the ordering dependency. And I think some targets
use tools to generate installed headers, which also shouldn't be
included in the ordering dependency.
So I suppose this amounts to a macro that means "generated header files
that are included by host code". I'm not going to suggest a name for that :)
Richard
