Complete HLSL -> SPIR-V translator

[johnkslang]

Requested HLSL features. If it's checked, it's been implemented and working for some workload. If a checked feature is not working correctly, there should be an issue reporting the incorrect behavior. A missing feature should be requested here.

• geometry, domain, and hull shaders
• member methods inside a structure, see issue HLSL: Struct/class members #535
• full pass through of attributes on loops/if/switch, e.g., [unroll], [flatten], etc., see issue HLSL: emit OpLoopMerge Unroll for HLSL [unroll] #836
• Maphalf to float. See issue HLSL: Halfs are not recognized as a type #492.
• namespace (about half done)
• conversions
  • structure cast of scalar: PS_OUTPUT __output__ = (PS_OUTPUT)(scalar)
  • inout arguments needing bidirectional conversion
  • smearing implicit-conversion
  • vector truncation conversion
  • vector of size 1 vs. scalar
• Basic RWBuffer support
• deference of textures
• arbitrary (structure) texture return-type, see issue StructuredBuffer syntax not supported #569.
• sub-vec4 return types from sampling
• compute shaders
  • numthreads
  • SV_DispatchThreadID -> gl_GlobalInvocationID
  • groupshared -> shared
• HLSL-specific preprocessing
  • trailing () parens are required/prohibited with an empty argument list in #defines
  • #include support
  • -D and -U for macros on command line
• class keyword, member functions, variables, static and non static
• class inheritance from interface see https://msdn.microsoft.com/en-us/library/windows/desktop/ff471421(v=vs.85).aspx
• Multi-dimensional arrays, ala float myfloat[4][5];
• minN types, ala https://msdn.microsoft.com/en-us/library/windows/desktop/bb509646(v=vs.85).aspx.
• vertical path hookup through to SPIR-V generation
• generic preprocessor (same as GLSL)
• scanner (keywords, identifiers, etc.)
• basic types: all int/uint/float/double scalar/vector/matrix
• basic recursive-decent language grammar: declarations, expressions, statements, loops, if-else, functions
• parsing of semantics, annotations, registers, etc. on declarations
• parsing of attributes on loops/if/switch, e.g., [unroll], [flatten], etc.
• basic symbol-table scoping
• switch statements, { } initializers, typedef
• templatized vector/matrix/etc. declaration grammar
• base set of all intrinsics mappable to existing operators
• HLSL-specific intrinsics, mapped to new operators
• vec1/mat1xN/matNx1-based, etc.
• DX10 style sampler declarations
• immediate (literal) samplers
• DX9 style sampler declarations
• 2DMS and Buffer texture support
• method-based image/texture lookup
• cbuffer/tbuffer
• register and packoffset for buffers
• in/out/inout qualifiers, e.g, void MyFunc(out float x)
• default parameters, e.g, void MyFunc(float x=3)
• overloaded function signature selection under implicit type conversion
• DX12 and beyond
  • syntax: ConstantBuffer
  • Wave Query,Wave Vote,Wave Broadcast,Wave Reduction,Wave Scan and Prefix,Quad-wide Shuffle operations,etc..
  • 64-bit types.
• printf

[ ] packoffset?

The "misc pending intrinsics" line above includes both the "unusual" intrinsics like printf as well as ones that accept either 1-vectors or Nx1 mats, which can be added, but aren't yet available.

[oscarbg]

also would be nice if you can add DX12 HLSL support.. parsing RootSignature,etc..
for ex. I see in:
https://github.com/Microsoft/DirectX-Graphics-Samples
miniengine AdaptExposureCS.hlsl shader

[RootSignature(PostEffects_RootSig)]
#define PostEffects_RootSig
"RootFlags(ALLOW_INPUT_ASSEMBLER_INPUT_LAYOUT), "
"CBV(b0, visibility = SHADER_VISIBILITY_VERTEX),"
"CBV(b0, visibility = SHADER_VISIBILITY_PIXEL),"
"DescriptorTable(SRV(t0, numDescriptors = 1), visibility = SHADER_VISIBILITY_PIXEL),"
"StaticSampler(s0, visibility = SHADER_VISIBILITY_PIXEL,"
"addressU = TEXTURE_ADDRESS_CLAMP,"
"addressV = TEXTURE_ADDRESS_CLAMP,"
"addressW = TEXTURE_ADDRESS_CLAMP,"
"filter = FILTER_MIN_MAG_MIP_LINEAR)"

[ ] in/out/inout qualifiers, e.g, void MyFunc(out float x);. Widely used - I have local code for this which I'll submit a PR for. Edit: #385.

[ ] Default parameters, e.g, void MyFunc(float x=3); but maybe this shouldn't move to the main list without a concrete use case.

DX10 style sampler declarations [in progress]

The only things missing there now are arguably orthogonal features such as sub-vec4 returns and 2DMS/Buffer, which is currently missing everywhere and touches a lot besides the decls. Otherwise, DX10 texture decls are working. (DX9 is still TODO, and the methods are still in progress).

conditional expressions (a ? b : c ternary operator).

(Edit for strikethrough now that this is in the main list)

I think this can be marked as done, modulo a few things with no feature mappings:

method-based image/texture lookup

DX9 texturing is still a TODO.