python3kgae added inline comments.
================
Comment at: clang/test/SemaHLSL/resource_binding_attr_error.hlsl:15
+// expected-error@+1 {{invalid space specifier 's2' used; expected 'space'
followed by an integer, like space1}}
+cbuffer a : register(b0, s2) {
+
----------------
beanz wrote:
> aaron.ballman wrote:
> > python3kgae wrote:
> > > aaron.ballman wrote:
> > > > Isn't this a re-definition of `a` which would cause an error?
> > > The name for cbuffer is not used.
> > > And no error should be reported for re-definition.
> > >
> > > Discussed with the team, have to keep it like this for back-compat reason.
> > Wow.
> >
> > Please either add a comment explaining why this bizarre situation gets no
> > diagnostic, or change the identifiers used so nobody else gets confused by
> > this when reading the test file.
> `cbuffer` is really weird (and hopefully someday will disappear entirely).
> From a language perspective it behaves almost more like a named anonymous
> namespace than a datatype (yea, I know that sentence makes no sense).
>
> The functionality that it provides is the ability to group a set of global
> constant variables so that the CPU-code can pack and provide those constants
> in known clumps.
>
> One might ask why have them named at all? Which is a fair question... The
> names do get exposed via the CPU-side reflection API which supports querying
> bindings and the like. We _probably_ shouldn't have ever allowed duplicate
> names, but as long as they have unique "slot" bindings the names don't really
> matter.
>
> `cbuffers` are important because we try to strip unused resources from
> shaders (because resource binding costs time). A `cbuffer` can either be
> striped entirely or not at all, which prevents individual binding elements
> from being stripped and simplifies shader calling code so the caller doesn't
> need to condition binding every individual resource element.
>
> We have newer structures in the language which can handle all of the use
> cases for `cbuffer`, however there are still some cases (particularly
> targeting older versions of windows), where `cbuffer` is still the dominant
> technique.
Changed the names to avoid confusion.
More comment is added to https://reviews.llvm.org/D129883
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D130033/new/
https://reviews.llvm.org/D130033
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