This patch replaces the `__arm_new_za`, `__arm_shared_za` and
`__arm_preserves_za` attributes in favour of:
* `__arm_new("za")`
* `__arm_in("za")`
* `__arm_out("za")`
* `__arm_inout("za")`
* `__arm_preserves("za")`
As described in https://github.com/ARM-software/acle/pull/276.
One change is that `__arm_in/out/inout/preserves(S)` are all mutually
exclusive, whereas previously it was fine to write `__arm_shared_za
__arm_preserves_za`. This case is now represented with `__arm_in("za")`.
The current implementation uses the same LLVM attributes under the hood,
since `__arm_in/out/inout` are all variations of "shared ZA", so can use
the existing `aarch64_pstate_za_shared` attribute in LLVM.
#77941 will add support for the new "zt0" state as introduced
with SME2.
This patch adds all the language-level function keywords defined in:
https://github.com/ARM-software/acle/pull/188 (merged)
https://github.com/ARM-software/acle/pull/261 (update after D148700 landed)
The keywords are used to control PSTATE.ZA and PSTATE.SM, which are
respectively used for enabling the use of the ZA matrix array and Streaming
mode. This information needs to be available on call sites, since the use
of ZA or streaming mode may have to be enabled or disabled around the
call-site (depending on the IR attributes set on the caller and the
callee). For calls to functions from a function pointer, there is no IR
declaration available, so the IR attributes must be added explicitly to the
call-site.
With the exception of '__arm_locally_streaming' and '__arm_new_za' the
information is part of the function's interface, not just the function
definition, and thus needs to be propagated through the
FunctionProtoType::ExtProtoInfo.
This patch adds the defintions of these keywords, as well as codegen and
semantic analysis to ensure conversions between function pointers are valid
and that no conflicting keywords are set. For example, '__arm_streaming'
and '__arm_streaming_compatible' are mutually exclusive.
Differential Revision: https://reviews.llvm.org/D127762
