This patch introduces `SemaHLSL` class, and moves some HLSL-related
functions there. No functional changes intended.
Removing "HLSL" from function names inside `SemaHLSL` is left for a
subsequent PR by HLSL contributors, if they deem that desirable.
This is a part of the effort to split `Sema` into smaller manageable
parts, and follows the example of OpenACC. See #82217, #84184, #87634
for additional context.
This is first part for support cbuffer/tbuffer.
The format for cbuffer/tbuffer is
BufferType [Name] [: register(b#)] { VariableDeclaration [: packoffset(c#.xyzw)]; ... };
More details at https://docs.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-constants
New keyword 'cbuffer' and 'tbuffer' are added.
New AST node HLSLBufferDecl is added.
Build AST for simple cbuffer/tbuffer without attribute support.
The special thing is variables declared inside cbuffer is exposed into global scope.
So isTransparentContext should return true for HLSLBuffer.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D129883
