On Dec 6, 2023, Jan Hubicka <hubi...@ucw.cz> wrote:
> I am sorry for sending this late.
No need to be sorry. Thank you very much for taking the time to review
and comment on it.
> I think the ipa changes are generally fine.
Phew :-)
>> +static inline bool
>> +strub_always_inline_p (cgraph_node *node)
>> +{
>> + return lookup_attribute ("always_inline", DECL_ATTRIBUTES (node->decl));
>> +}
> We may want to ahve this as cgraph_node::always_inline_p since there are
> now quite many places we look up this attribute.
Can do. Would such a global refactoring still be welcome at this stage,
or should it be saved for stage1? I guess it could still go in, so
simple it is...
>> +/* The strub pass proper adjusts types, signatures, and at-calls calls, and
>> + splits internal-strub functions. */
>> +
>> +unsigned int
>> +pass_ipa_strub::execute (function *)
>> +{
>> + cgraph_node *onode;
>> +
>> + ipa_strub_set_mode_for_new_functions ();
>> +
>> + /* First, adjust the signature of at-calls functions. We adjust types of
>> + at-calls functions first, so that we don't modify types in place unless
>> + strub is explicitly requested. */
> I think Martin ma have more specific opinion on this, but since this is
> not running as the ipa pass during WPA stage, I think the param
> modification infrastructure is not really that much hepful here.
Hmm... I wonder if this is indeed what Martin refers to. There are two
separate pieces of logic for parm-tweaking, one for "at-calls" strub
functions, that get the signature and the type of the function itself
modified (akin to adding the implicit "this" parameter to a C++
nonstatic member-function), and is implemented under the comment above,
and there's the splitting-out of "internal" strub function bodies into a
clone with a modified signature, that is implemented elsewhere. The
latter uses cloning and thus (some, but not much) IPA param modification
infrastructure, but the former doesn't IIRC.
>> + /* ??? Maybe we could adjust it instead. */
>> + if (drop_fnspec)
>> + remove_named_attribute_unsharing ("fn spec",
>> + &TYPE_ATTRIBUTES (nftype));
> ipa param modification also doesn't know how to update fn spec, this is
> something we should look into next stage1...
> There is also access attribute which speaks directly about individual
> arugments, perhaps you want to drop this one too?
Hmm, I can't recall whether I've come across it before (it sounds
vaguely familiar, but unless they become "fn spec" (ISTR synthetic "fn
spec"s), I think I'd have dealt with them already.
I'll dig it a little further.
> Are variadic thunks working with scrubbing?
Yeah, the wrapper is rewritten to call va_start itself, and the
split-out wrapped body is modified to call va_copy instead of va_start.
--
Alexandre Oliva, happy hacker https://FSFLA.org/blogs/lxo/
Free Software Activist GNU Toolchain Engineer
More tolerance and less prejudice are key for inclusion and diversity
Excluding neuro-others for not behaving ""normal"" is *not* inclusive
