Re: [PATCH, OpenACC 2.7] readonly modifier support in front-ends

[Tobias Burnus <tobias@codesourcery.com>]

Hi,

just a remark regarding OpenMP. With

...omp ... firstprivate(var) allocator(omp_const_mem_alloc: var) one can also create constant memory in OpenMP.
Likewise with a custom allocator that uses the memory space
omp_const_mem_space, which is then a run-time thing. I don't think
that's particular useful on the host as the !PROT_WRITE property is a
memory-page thing which requires to allocate a multiple of a page size
(and after writing the value, mprotect can make it read only). But I
think it can be useful on the device (cf. OpenACC). OpenMP and OpenACC
likely differ in terms of whether an entry is in the mapping table
(firstprivate vs copy) and in the ref count. In any case, it would be
good to have the code written such that both OpenACC's and OpenMP's use
case can share as much code as possible, even if only OpenACC is
initially supported. Tobias PS: I should eventually have a closer look
at your patch!

On 10.07.23 20:33, Chung-Lin Tang wrote:
> this patch contains support for the 'readonly' modifier in copyin clauses
> and the cache directive.
>
> As we discussed earlier, the work for actually linking this to middle-end
> points-to analysis is a somewhat non-trivial issue. This first patch allows
> the language feature to be used in OpenACC directives first (with no effect for now).
> The middle-end changes are probably going to be a later patch.
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