[milestone] Render Simple Triangle

[damyanp]

Vertex and Pixel shaders have been implemented enough that a simple triangle can be rendered.

Workstreams

Language (#21)

• Semantic language components TBD (see Semantics workstream)

Semantics (#25)

• Prefix-stable Signature Element packing and diagnostics #140
• Semantic: SV_Position vertex shader output #141
• Semantic: SV_Target pixel shader output #142
• Design Signature metadata for IR #143
• IRGen: Capture signatures to metadata #144
• Add LoadInput intrinsic and calls to initialize basic scalar/vector for wrapped entry function outputs #145
• Add StoreOutput intrinsic and calls to store basic scalar/vector for wrapped entry function outputs #146

Resources (#8)

• [HLSL][DirectX] Texture and Sampler resource types and operations llvm-project#101558

DirectX Container (#9)

• Semantic support in PSV0 part.
• Fill Input/Output Signature parts.