Implement the `InstanceID` HLSL Function

farzonl commented 5 months ago

[ ] Implement InstanceID clang builtin,
[ ] Link InstanceID clang builtin with hlsl_intrinsics.h
[ ] Add sema checks for InstanceID to CheckHLSLBuiltinFunctionCall in SemaChecking.cpp
[ ] Add codegen for InstanceID to EmitHLSLBuiltinExpr in CGBuiltin.cpp
[ ] Add codegen tests to clang/test/CodeGenHLSL/builtins/InstanceID.hlsl
[ ] Add sema tests to clang/test/SemaHLSL/BuiltIns/InstanceID-errors.hlsl
[ ] Create the int_dx_InstanceID intrinsic in IntrinsicsDirectX.td
[ ] Create the DXILOpMapping of int_dx_InstanceID to 141 in DXIL.td
[ ] Create the InstanceID.ll and InstanceID_errors.ll tests in llvm/test/CodeGen/DirectX/
[ ] Create the int_spv_InstanceID intrinsic in IntrinsicsSPIRV.td
[ ] In SPIRVInstructionSelector.cpp create the InstanceID lowering and map it to int_spv_InstanceID in SPIRVInstructionSelector::selectIntrinsic.
[ ] Create SPIR-V backend test case in llvm/test/CodeGen/SPIRV/hlsl-intrinsics/InstanceID.ll

DirectX

DXIL Opcode	DXIL OpName	Shader Model	Shader Stages
141	InstanceID	6.3	('library', 'intersection', 'anyhit', 'closesthit')

SPIR-V

## Description

` InstanceCustomIndexKHR ` A variable decorated with the ` InstanceCustomIndexKHR ` decoration will contain the application-defined value of the instance that intersects the current ray. This variable contains the value that was specified in [VkAccelerationStructureInstanceKHR](https://registry.khronos.org/vulkan/specs/1.3-extensions/man/html/None) :: ` instanceCustomIndex ` for the current acceleration structure instance in the lower 24 bits and the upper 8 bits will be zero.

Valid Usage

- VUID-InstanceCustomIndexKHR-InstanceCustomIndexKHR-04251 The ` InstanceCustomIndexKHR ` decoration **must** be used only within the ` IntersectionKHR ` , ` AnyHitKHR ` , or ` ClosestHitKHR ` ` Execution ` ` Model ` - VUID-InstanceCustomIndexKHR-InstanceCustomIndexKHR-04252 The variable decorated with ` InstanceCustomIndexKHR ` **must** be declared using the ` Input ` ` Storage ` ` Class ` - VUID-InstanceCustomIndexKHR-InstanceCustomIndexKHR-04253 The variable decorated with ` InstanceCustomIndexKHR ` **must** be declared as a scalar 32-bit integer value

Test Case(s)

Example 1

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

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

SPIRV Example(s):

Example 2

//dxc InstanceID_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 = InstanceID();
}

HLSL:

The user-provided identifier for the instance on the bottom-level acceleration structure instance within the top-level structure.

Syntax

uint InstanceID();

Remarks

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

llvm / llvm-project