Adds support for accessing individual resources from fixed-size global resource arrays.
Design proposal:
https://github.com/llvm/wg-hlsl/blob/main/proposals/0028-resource-arrays.md
Enables indexing into globally scoped, fixed-size resource arrays to retrieve individual resources. The initialization logic is primarily handled during codegen. When a global resource array is indexed, the
codegen translates the `ArraySubscriptExpr` AST node into a constructor call for the corresponding resource record type and binding.
To support this behavior, Sema needs to ensure that:
- The constructor for the specific resource type is instantiated.
- An implicit binding attribute is added to resource arrays that lack explicit bindings (#152452).
Closes#145424
Adds constructor for resources with implicit binding and applies it to
all resources without binding at the global scope.
Adds Clang builtin function
`__builtin_hlsl_resource_handlefromimplicitbinding` that gets translated
to `llvm.dx|spv.resource.handlefromimplicitbinding` intrinsic calls.
Specific bindings are assigned in DXILResourceImplicitBinding pass.
Design proposals:
https://github.com/llvm/wg-hlsl/blob/main/proposals/0024-implicit-resource-binding.mdhttps://github.com/llvm/wg-hlsl/blob/main/proposals/0025-resource-constructors.md
One change from the proposals is that the `orderId` parameter is added
onto the constructor. Originally it was supposed to be generated in
codegen when the `llvm.dx|spv.resource.handlefromimplicitbinding` call
is emitted, but that is not possible because the call is inside a
constructor, and the constructor body is generated once per resource
type and not resource instance. So the only way to inject instance-based
data like `orderId` into the
`llvm.dx|spv.resource.handlefromimplicitbinding` call is that it must
come in via the constructor argument.
Closes#136784
Implicit bindings will cause very confusing crashes in the backend at
present, so this is intended at least partially as a stop gap until we
get them implemented (see #110722).
However, I do think that this is useful in the longer term as well as an
off-by-default warning, as it is quite easy to miss a binding or two
when using explicit bindings and the results of that can be surprisingly
hard to debug. I've filed #135907 to track turning this into an
off-by-default warning or removing it eventually as we see fit.
To consolidate behavior of function mangling and limit the number of
places that ABI changes will need to be made, this switches the DirectX
target used for HLSL to use the Itanium ABI from the Microsoft ABI. The
Itanium ABI has greater flexibility in decisions regarding mangling of
new types of which we have more than a few yet to add.
One effect of this will be that linking library shaders compiled with
DXC will not be possible with shaders compiled with clang. That isn't
considered a terribly interesting use case and one that would likely
have been onerous to maintain anyway.
This involved adding a function to call all global destructors as the
Microsoft ABI had done.
This requires a few changes to tests. Most notably the mangling style
has changed which accounts for most of the changes. In making those
changes, I took the opportunity to harmonize some very similar tests for
greater consistency. I also shaved off some unneeded run flags that had
probably been copied over from one test to another.
Other changes effected by using the new ABI include using different
types when manipulating smaller bitfields, eliminating an unnecessary
alloca in one instance in this-assignment.hlsl, changing the way static
local initialization is guarded, and changing the order of inout
parameters getting copied in and out. That last is a subtle change in
functionality, but one where there was sufficient inconsistency in the
past that standardizing is important, but the particular direction of
the standardization is less important for the sake of existing shaders.
fixes#110736
Thread init guards are generated for local static variables when using
the Microsoft CXX ABI. This ABI is also used for HLSL generation, but
DXIL doesn't need the corresponding _Init_thread_header/footer calls and
doesn't really have a way to handle them in its output targets.
This modifies the language ops when the target is DXIL to exclude this
so that they won't be generated and an alternate guardvar method is used
that is compatible with the usage.
Done to facilitate testing for #89806, but isn't really related
