Implement the RayFlags HLSL Function

[farzonl]

• Implement RayFlags clang builtin,
• Link RayFlags clang builtin with hlsl_intrinsics.h
• Add sema checks for RayFlags to CheckHLSLBuiltinFunctionCall in SemaChecking.cpp
• Add codegen for RayFlags to EmitHLSLBuiltinExpr in CGBuiltin.cpp
• Add codegen tests to clang/test/CodeGenHLSL/builtins/RayFlags.hlsl
• Add sema tests to clang/test/SemaHLSL/BuiltIns/RayFlags-errors.hlsl
• Create the int_dx_RayFlags intrinsic in IntrinsicsDirectX.td
• Create the DXILOpMapping of int_dx_RayFlags to 144 in DXIL.td
• Create the RayFlags.ll and RayFlags_errors.ll tests in llvm/test/CodeGen/DirectX/
• Create the int_spv_RayFlags intrinsic in IntrinsicsSPIRV.td
• In SPIRVInstructionSelector.cpp create the RayFlags lowering and map it to int_spv_RayFlags in SPIRVInstructionSelector::selectIntrinsic.
• Create SPIR-V backend test case in llvm/test/CodeGen/SPIRV/hlsl-intrinsics/RayFlags.ll

DirectX

DXIL Opcode	DXIL OpName	Shader Model	Shader Stages
144	RayFlags	6.3	('library', 'intersection', 'anyhit', 'closesthit', 'miss')

SPIR-V

IncomingRayFlagsKHR

Short Description

IncomingRayFlagsKHR - Flags used to trace a ray

Description

IncomingRayFlagsKHR
A variable with the IncomingRayFlagsKHR decoration will contain the
ray flags passed in to the trace call that invoked this particular
shader. Setting pipeline flags on the ray tracing pipeline must not
cause any corresponding flags to be set in variables with this
decoration.

Valid Usage

• 
  VUID-IncomingRayFlagsKHR-IncomingRayFlagsKHR-04248
  
  The IncomingRayFlagsKHR decoration must be used only within
  the IntersectionKHR , AnyHitKHR , ClosestHitKHR , or
  MissKHR Execution Model

• 
  VUID-IncomingRayFlagsKHR-IncomingRayFlagsKHR-04249
  
  The variable decorated with IncomingRayFlagsKHR must be
  declared using the Input Storage Class

• 
  VUID-IncomingRayFlagsKHR-IncomingRayFlagsKHR-04250
  
  The variable decorated with IncomingRayFlagsKHR must be
  declared as a scalar 32-bit integer value

Test Case(s)

Example 1

//dxc RayFlags_test.hlsl -T lib_6_8 -enable-16bit-types -O0

export uint fn() {
    return RayFlags();
}

SPIRV Example(s):

Example 2

//dxc RayFlags_spirv_test.hlsl -T lib_6_8 -E fn -enable-16bit-types -spirv -fspv-target-env=universal1.5 -fcgl -O0

[shader("intersection")]
void fn() {
uint 	ret = RayFlags();
}

HLSL:

An unsigned integer containing the current ray_flag flags.

Syntax

uint RayFlags();

Remarks

This function can be called from the following raytracing shader types:

• Any Hit Shader
• Closest Hit Shader
• Intersection Shader
• Miss Shader

See also

Direct3D 12 Raytracing HLSL Reference