Translates `cbuffer` declaration blocks to `target("dx.CBuffer")` type. Creates global variables in `hlsl_constant` address space for all `cbuffer` constant and adds metadata describing which global constant belongs to which constant buffer. For explicit constant buffer layout information an explicit layout type `target("dx.Layout")` is used. This might change in the future.

The constant globals are temporary and will be removed in upcoming pass that will translate `load` instructions in the `hlsl_constant` address space to constant buffer load intrinsics calls off a CBV handle (#124630, #112992).

See [Constant buffer design
doc](llvm/wg-hlsl#94) for more details.

Fixes #113514, #106596

This introduces a pass that walks accesses to globals in cbuffers and
replaces them with accesses via the cbuffer handle itself. The logic to
interpret the cbuffer metadata is kept in `lib/Frontend/HLSL` so that it
can be reused by other consumers of that metadata.

Fixes llvm#124630.

This introduces a pass that walks accesses to globals in cbuffers and
replaces them with accesses via the cbuffer handle itself. The logic to
interpret the cbuffer metadata is kept in `lib/Frontend/HLSL` so that it
can be reused by other consumers of that metadata.

Fixes llvm#124630.

This introduces a pass that walks accesses to globals in cbuffers and
replaces them with accesses via the cbuffer handle itself. The logic to
interpret the cbuffer metadata is kept in `lib/Frontend/HLSL` so that it
can be reused by other consumers of that metadata.

Fixes llvm#124630.