[HLSL] Split [[hlsl::resource_class]] out of the HLSLResource attribute

[bogner]

Create a new hlsl::resource_class attribute to replace the resource class argument of the HLSLResource unspellable attribute. The attribute should be spellable so that we can use it to simplify testing.

AC:

• Decide what the spelling should be
• The attribute [[hlsl::resource_class(...)]] can be applied to types in HLSL source
• The attribute is parametrized with uav, srv, cbuffer, or sampler
• HLSLResource no longer has a ResourceClass argument, and existing code that used that now uses the new attribute

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Justin Bogner (bogner)

Create a new `hlsl::resource_class` attribute to replace the resource class argument of the HLSLResource unspellable attribute. The attribute should be spellable so that we can use it to simplify testing.

AC:

• Decide what the spelling should be
• The attribute [[hlsl::resource_class(...)]] can be applied to types in HLSL source
• The attribute is parametrized with uav, srv, cbuffer, or sampler
• HLSLResource no longer has a ResourceClass argument, and existing code that used that now uses the new attribute

[llvmbot]

@llvm/issue-subscribers-clang-codegen

Author: Justin Bogner (bogner)

Create a new `hlsl::resource_class` attribute to replace the resource class argument of the HLSLResource unspellable attribute. The attribute should be spellable so that we can use it to simplify testing.

AC:

• Decide what the spelling should be
• The attribute [[hlsl::resource_class(...)]] can be applied to types in HLSL source
• The attribute is parametrized with uav, srv, cbuffer, or sampler
• HLSLResource no longer has a ResourceClass argument, and existing code that used that now uses the new attribute