path: root/source/slang/slang-emit-cuda.cpp

// slang-emit-cuda.cpp
#include "slang-emit-cuda.h"

#include "../core/slang-writer.h"

#include "slang-emit-source-writer.h"
#include "slang-mangled-lexer.h"

#include <assert.h>

namespace Slang {



void CUDAExtensionTracker::finalize()
{
    if (isBaseTypeRequired(BaseType::Half))
    {
        // The cuda_fp16.hpp header indicates the need is for version 5.3, but when this is tried
        // NVRTC says it cannot load builtins.
        // The lowest version that this does work for is 6.0, so that's what we use here.

        // https://docs.nvidia.com/cuda/nvrtc/index.html#group__options
        requireSMVersion(SemanticVersion(6, 0));
    }
}

UnownedStringSlice CUDASourceEmitter::getBuiltinTypeName(IROp op)
{
    switch (op)
    {
        case kIROp_VoidType:    return UnownedStringSlice("void");
        case kIROp_BoolType:    return UnownedStringSlice("bool");

        case kIROp_Int8Type:    return UnownedStringSlice("char");
        case kIROp_Int16Type:   return UnownedStringSlice("short");
        case kIROp_IntType:     return UnownedStringSlice("int");
        case kIROp_Int64Type:   return UnownedStringSlice("longlong");

        case kIROp_UInt8Type:   return UnownedStringSlice("uchar");
        case kIROp_UInt16Type:  return UnownedStringSlice("ushort");
        case kIROp_UIntType:    return UnownedStringSlice("uint");
        case kIROp_UInt64Type:  return UnownedStringSlice("ulonglong");
#if SLANG_PTR_IS_64
        case kIROp_IntPtrType:  return UnownedStringSlice("int64_t");
        case kIROp_UIntPtrType: return UnownedStringSlice("uint64_t");
#else
        case kIROp_IntPtrType:  return UnownedStringSlice("int");
        case kIROp_UIntPtrType: return UnownedStringSlice("uint");
#endif
        case kIROp_HalfType:
        {
            m_extensionTracker->requireBaseType(BaseType::Half);
            return UnownedStringSlice("__half");
        }

        case kIROp_FloatType:   return UnownedStringSlice("float");
        case kIROp_DoubleType:  return UnownedStringSlice("double");
        default:                return UnownedStringSlice();
    }
}


UnownedStringSlice CUDASourceEmitter::getVectorPrefix(IROp op)
{
    switch (op)
    {
        case kIROp_BoolType:    return UnownedStringSlice("bool");

        case kIROp_Int8Type:    return UnownedStringSlice("char");
        case kIROp_Int16Type:   return UnownedStringSlice("short");
        case kIROp_IntType:     return UnownedStringSlice("int");
        case kIROp_Int64Type:   return UnownedStringSlice("longlong");

        case kIROp_UInt8Type:   return UnownedStringSlice("uchar");
        case kIROp_UInt16Type:  return UnownedStringSlice("ushort");
        case kIROp_UIntType:    return UnownedStringSlice("uint");
        case kIROp_UInt64Type:  return UnownedStringSlice("ulonglong");

        case kIROp_HalfType:
        {
            m_extensionTracker->requireBaseType(BaseType::Half);
            return UnownedStringSlice("__half");
        }

        case kIROp_FloatType:   return UnownedStringSlice("float");
        case kIROp_DoubleType:  return UnownedStringSlice("double");
        default:                return UnownedStringSlice();
    }
}

void CUDASourceEmitter::emitTempModifiers(IRInst* temp)
{
    CPPSourceEmitter::emitTempModifiers(temp);
    if (as<IRModuleInst>(temp->getParent()))
    {
        m_writer->emit("__device__ ");
    }
}

SlangResult CUDASourceEmitter::_calcCUDATextureTypeName(IRTextureTypeBase* texType, StringBuilder& outName)
{
    // Not clear how to do this yet
    if (texType->isMultisample())
    {
        return SLANG_FAIL;
    }

    switch (texType->getAccess())
    {
        case SLANG_RESOURCE_ACCESS_READ:
        {
            outName << "CUtexObject";
            return SLANG_OK;
        }
        case SLANG_RESOURCE_ACCESS_READ_WRITE:
        {
            outName << "CUsurfObject";
            return SLANG_OK;
        }
        default: break;
    }
    return SLANG_FAIL;
}

SlangResult CUDASourceEmitter::calcTypeName(IRType* type, CodeGenTarget target, StringBuilder& out)
{
    SLANG_UNUSED(target);

    // The names CUDA produces are all compatible with 'C' (ie they aren't templated types)
    SLANG_ASSERT(target == CodeGenTarget::CUDASource || target == CodeGenTarget::CSource);

    switch (type->getOp())
    {
        case kIROp_VectorType:
        {
            auto vecType = static_cast<IRVectorType*>(type);
            auto vecCount = int(getIntVal(vecType->getElementCount()));
            const IROp elemType = vecType->getElementType()->getOp();

            UnownedStringSlice prefix = getVectorPrefix(elemType);
            if (prefix.getLength() <= 0)
            {
                return SLANG_FAIL;
            }
            out << prefix << vecCount;
            return SLANG_OK;
        }
        case kIROp_TensorViewType:
        {
            out << "TensorView";
            return SLANG_OK;
        }
        default:
        {
            if (isNominalOp(type->getOp()))
            {
                out << getName(type);
                return SLANG_OK;
            }

            if (IRBasicType::isaImpl(type->getOp()))
            {
                out << getBuiltinTypeName(type->getOp());
                return SLANG_OK;
            }

            if (auto texType = as<IRTextureTypeBase>(type))
            {
                // We don't support TextureSampler, so ignore that
                if (texType->getOp() != kIROp_TextureSamplerType)
                {
                    return _calcCUDATextureTypeName(texType, out);
                }
            }

            switch (type->getOp())
            {
                case kIROp_SamplerStateType:                    out << "SamplerState"; return SLANG_OK;
                case kIROp_SamplerComparisonStateType:          out << "SamplerComparisonState"; return SLANG_OK;
                default: break;
            }

            break;
        }
    }

    if (auto untypedBufferType = as<IRUntypedBufferResourceType>(type)) {
        switch (untypedBufferType->getOp())
        {
            case kIROp_RaytracingAccelerationStructureType:
            {
                m_writer->emit("OptixTraversableHandle");
                return SLANG_OK;
                break;
            }

            default: break;
        }
    }

    return Super::calcTypeName(type, target, out);
}

void CUDASourceEmitter::emitLayoutSemanticsImpl(IRInst* inst, char const* uniformSemanticSpelling)
{
    Super::emitLayoutSemanticsImpl(inst, uniformSemanticSpelling);
}

void CUDASourceEmitter::emitParameterGroupImpl(IRGlobalParam* varDecl, IRUniformParameterGroupType* type)
{
    auto elementType = type->getElementType();

    m_writer->emit("extern \"C\" __constant__ ");
    emitType(elementType, "SLANG_globalParams");
    m_writer->emit(";\n");

    m_writer->emit("#define ");
    m_writer->emit(getName(varDecl));
    m_writer->emit(" (&SLANG_globalParams)\n");
}

void CUDASourceEmitter::emitEntryPointAttributesImpl(IRFunc* irFunc, IREntryPointDecoration* entryPointDecor)
{
    SLANG_UNUSED(irFunc);
    SLANG_UNUSED(entryPointDecor);
}

void CUDASourceEmitter::emitFunctionPreambleImpl(IRInst* inst)
{
    if (!inst)
        return;
    if (inst->findDecoration<IREntryPointDecoration>())
    {
        m_writer->emit("extern \"C\" __global__ ");
        return;
    }

    if (inst->findDecoration<IRCudaKernelDecoration>())
    {
        m_writer->emit("__global__ ");
    }
    else if (inst->findDecoration<IRCudaHostDecoration>())
    {
        m_writer->emit("__host__ ");
    }
    else
    {
        m_writer->emit("__device__ ");
    }
}

String CUDASourceEmitter::generateEntryPointNameImpl(IREntryPointDecoration* entryPointDecor)
{
    // We have an entry-point function in the IR module, which we
    // will want to emit as a `__global__` function in the generated
    // CUDA C++.
    //
    // The most common case will be a compute kernel, in which case
    // we will emit the function more or less as-is, including
    // usingits original name as the name of the global symbol.
    //
    String funcName = Super::generateEntryPointNameImpl(entryPointDecor);
    String globalSymbolName = funcName;

    // We also suport emitting ray tracing kernels for use with
    // OptiX, and in that case the name of the global symbol
    // must be prefixed to indicate to the OptiX runtime what
    // stage it is to be compiled for.
    //
    auto stage = entryPointDecor->getProfile().getStage();
    switch( stage )
    {
    default:
        break;

#define CASE(STAGE, PREFIX) \
    case Stage::STAGE: globalSymbolName = #PREFIX + funcName; break

    // Optix 7 Guide, Section 6.1 (Program input)
    //
    // > The input PTX should include one or more NVIDIA OptiX programs.
    // > The type of program affects how the program can be used during
    // > the execution of the pipeline. These program types are specified
    // by prefixing the program name with the following:
    //
    // >    Program type        Function name prefix
    CASE(   RayGeneration,      __raygen__);
    CASE(   Intersection,       __intersection__);
    CASE(   AnyHit,             __anyhit__);
    CASE(   ClosestHit,         __closesthit__);
    CASE(   Miss,               __miss__);
    CASE(   Callable,           __direct_callable__);
    //
    // There are two stages (or "program types") supported by OptiX
    // that Slang currently cannot target:
    //
    // CASE(ContinuationCallable,   __continuation_callable__);
    // CASE(Exception,              __exception__);
    //
#undef CASE
    }

    return globalSymbolName;
}

void CUDASourceEmitter::emitGlobalRTTISymbolPrefix()
{
    m_writer->emit("__constant__ ");
}

void CUDASourceEmitter::emitLoopControlDecorationImpl(IRLoopControlDecoration* decl)
{
    if (decl->getMode() == kIRLoopControl_Unroll)
    {
        m_writer->emit("#pragma unroll\n");
    }
}

void CUDASourceEmitter::_emitInitializerListValue(IRType* dstType, IRInst* value)
{
    // When constructing a matrix or vector from a single value this is handled by the default path

    switch (value->getOp())
    {
        case kIROp_MakeVector:
        case kIROp_MakeMatrix:
        {
            IRType* type = value->getDataType();

            // If the types are the same, we can can just break down and use
            if (dstType == type)
            {
                if (auto vecType = as<IRVectorType>(type))
                {
                    if (UInt(getIntVal(vecType->getElementCount())) == value->getOperandCount())
                    {
                        emitType(type);
                        _emitInitializerList(vecType->getElementType(), value->getOperands(), value->getOperandCount());
                        return;
                    }
                }
                else if (auto matType = as<IRMatrixType>(type))
                {
                    const Index colCount = Index(getIntVal(matType->getColumnCount()));
                    const Index rowCount = Index(getIntVal(matType->getRowCount()));

                    // TODO(JS): If num cols = 1, then it *doesn't* actually return a vector.
                    // That could be argued is an error because we want swizzling or [] to work.
                    IRBuilder builder(matType->getModule());
                    builder.setInsertBefore(matType);
                    const Index operandCount = Index(value->getOperandCount());

                    // Can init, with vectors.
                    // For now special case if the rowVectorType is not actually a vector (when elementSize == 1)
                    if (operandCount == rowCount)
                    {
                        // Emit the braces for the Matrix struct, and then each row vector in its own line.
                        emitType(matType);
                        m_writer->emit("{\n");
                        m_writer->indent();
                        for (Index i = 0; i < rowCount; ++i)
                        {
                            if (i != 0) m_writer->emit(",\n");
                            emitType(matType->getElementType());
                            m_writer->emit(colCount);
                            _emitInitializerList(matType->getElementType(), value->getOperand(i)->getOperands(), colCount);
                        }
                        m_writer->dedent();
                        m_writer->emit("\n}");
                        return;
                    }
                    else if (operandCount == rowCount * colCount)
                    {
                        // Handle if all are explicitly defined
                        IRType* elementType = matType->getElementType();                                        
                        IRUse* operands = value->getOperands();

                        // Emit the braces for the Matrix struct, and the elements of each row in its own line.
                        emitType(matType);
                        m_writer->emit("{\n");
                        m_writer->indent();
                        for (Index i = 0; i < rowCount; ++i)
                        {
                            if (i != 0) m_writer->emit(",\n");
                            _emitInitializerListContent(elementType, operands, colCount);
                            operands += colCount;
                        }
                        m_writer->dedent();
                        m_writer->emit("\n}");
                        return;
                    }
                }
            }
                      
            break;
        }
    }

    // All other cases we just use the default emitting - might not work on arrays defined in global scope on CUDA though
    emitOperand(value, getInfo(EmitOp::General));
}

void CUDASourceEmitter::_emitInitializerListContent(IRType* elementType, IRUse* operands, Index operandCount)
{
    for (Index i = 0; i < operandCount; ++i)
    {
        if (i != 0) m_writer->emit(", ");
        _emitInitializerListValue(elementType, operands[i].get());
    }
}


void CUDASourceEmitter::_emitInitializerList(IRType* elementType, IRUse* operands, Index operandCount)
{
    m_writer->emit("{\n");
    m_writer->indent();

    _emitInitializerListContent(elementType, operands, operandCount);

    m_writer->dedent();
    m_writer->emit("\n}");
}

void CUDASourceEmitter::emitIntrinsicCallExprImpl(IRCall* inst, IRTargetIntrinsicDecoration* targetIntrinsic, EmitOpInfo const& inOuterPrec)
{
    if (targetIntrinsic->getDefinition().startsWith("__half"))
        m_extensionTracker->requireBaseType(BaseType::Half);
    Super::emitIntrinsicCallExprImpl(inst, targetIntrinsic, inOuterPrec);
}

bool CUDASourceEmitter::tryEmitInstExprImpl(IRInst* inst, const EmitOpInfo& inOuterPrec)
{
    switch(inst->getOp())
    {
        case kIROp_MakeVector:
        case kIROp_MakeVectorFromScalar:
        {
            m_writer->emit("make_");
            emitType(inst->getDataType());
            m_writer->emit("(");
            bool isFirst = true;
            char xyzwNames[] = "xyzw";
            for (UInt i = 0; i < inst->getOperandCount(); i++)
            {
                auto arg = inst->getOperand(i);
                if (auto vectorType = as<IRVectorType>(arg->getDataType()))
                {
                    for (int j = 0; j < cast<IRIntLit>(vectorType->getElementCount())->getValue(); j++)
                    {
                        if (isFirst)
                            isFirst = false;
                        else
                            m_writer->emit(", ");
                        auto outerPrec = getInfo(EmitOp::General);
                        auto prec = getInfo(EmitOp::Postfix);
                        emitOperand(arg, leftSide(outerPrec, prec));
                        m_writer->emit(".");
                        m_writer->emitChar(xyzwNames[j]);
                    }
                }
                else
                {
                    if (isFirst)
                        isFirst = false;
                    else
                        m_writer->emit(", ");
                    emitOperand(arg, getInfo(EmitOp::General));
                }
            }
            m_writer->emit(")");
            return true;
        }
        case kIROp_FloatCast:
        case kIROp_CastIntToFloat:
        case kIROp_IntCast:
        case kIROp_CastFloatToInt:
        {
            if (auto dstVectorType = as<IRVectorType>(inst->getDataType()))
            {
                m_writer->emit("make_");
                emitType(inst->getDataType());
                m_writer->emit("(");
                bool isFirst = true;
                char xyzwNames[] = "xyzw";
                for (UInt i = 0; i < inst->getOperandCount(); i++)
                {
                    auto arg = inst->getOperand(i);
                    if (auto vectorType = as<IRVectorType>(arg->getDataType()))
                    {
                        for (int j = 0; j < cast<IRIntLit>(vectorType->getElementCount())->getValue(); j++)
                        {
                            if (isFirst)
                                isFirst = false;
                            else
                                m_writer->emit(", ");
                            m_writer->emit("(");
                            emitType(dstVectorType->getElementType());
                            m_writer->emit(")");
                            auto outerPrec = getInfo(EmitOp::General);
                            auto prec = getInfo(EmitOp::Postfix);
                            emitOperand(arg, leftSide(outerPrec, prec));
                            m_writer->emit(".");
                            m_writer->emitChar(xyzwNames[j]);
                        }
                    }
                    else
                    {
                        if (isFirst)
                            isFirst = false;
                        else
                            m_writer->emit(", ");
                        m_writer->emit("(");
                        emitType(dstVectorType->getElementType());
                        m_writer->emit(")");
                        emitOperand(arg, getInfo(EmitOp::General));
                    }
                }
                m_writer->emit(")");
                return true;
            }
            else if (const auto matrixType = as<IRMatrixType>(inst->getDataType()))
            {
                m_writer->emit("make");
                emitType(inst->getDataType());
                m_writer->emit("(");
                for (UInt i = 0; i < inst->getOperandCount(); i++)
                {
                    auto arg = inst->getOperand(i);
                    if (i > 0)
                        m_writer->emit(", ");
                    emitOperand(arg, getInfo(EmitOp::General));
                }
                m_writer->emit(")");
                return true;
            }
            return false;
        }
        case kIROp_MakeMatrix:
        case kIROp_MakeMatrixFromScalar:
        case kIROp_MatrixReshape:
        {
            m_writer->emit("make");
            emitType(inst->getDataType());
            m_writer->emit("(");
            for (UInt i = 0; i < inst->getOperandCount(); i++)
            {
                auto arg = inst->getOperand(i);
                if (i > 0)
                    m_writer->emit(", ");
                emitOperand(arg, getInfo(EmitOp::General));
            }
            m_writer->emit(")");
            return true;
        }
        case kIROp_MakeArray:
        {
            IRType* dataType = inst->getDataType();
            IRArrayType* arrayType = as<IRArrayType>(dataType);

            IRType* elementType = arrayType->getElementType();

            // Emit braces for the FixedArray struct. 

            _emitInitializerList(elementType, inst->getOperands(), Index(inst->getOperandCount()));

            return true;
        }
        case kIROp_WaveMaskBallot:
        {
             m_extensionTracker->requireSMVersion(SemanticVersion(7, 0));

            m_writer->emit("__ballot_sync(");
            emitOperand(inst->getOperand(0), getInfo(EmitOp::General));
            m_writer->emit(", ");
            emitOperand(inst->getOperand(1), getInfo(EmitOp::General));
            m_writer->emit(")");
            return true;
        }
        case kIROp_WaveMaskMatch:
        {
             m_extensionTracker->requireSMVersion(SemanticVersion(7, 0));

            m_writer->emit("__match_any_sync(");
            emitOperand(inst->getOperand(0), getInfo(EmitOp::General));
            m_writer->emit(", ");
            emitOperand(inst->getOperand(1), getInfo(EmitOp::General));
            m_writer->emit(")");
            return true;
        }
        case kIROp_GetOptiXRayPayloadPtr:
        {
            m_writer->emit("(");
            emitType(inst->getDataType());
            m_writer->emit(")getOptiXRayPayloadPtr()");
            return true;
        }
        case kIROp_GetOptiXHitAttribute:
        {
            auto typeToFetch = inst->getOperand(0);
            auto idxInst = as<IRIntLit>(inst->getOperand(1));
            IRIntegerValue idx = idxInst->getValue();
            if (typeToFetch->getOp() == kIROp_FloatType) {
                m_writer->emit("__int_as_float(optixGetAttribute_");
            }
            else
            {
                m_writer->emit("optixGetAttribute_");
            }
            m_writer->emit(idx);
            if (typeToFetch->getOp() == kIROp_FloatType)
            {
                m_writer->emit("())");
            }
            else
            {
                m_writer->emit("()");
            }
            return true;
        }
        case kIROp_GetOptiXSbtDataPtr:
        {
            m_writer->emit("((");
            emitType(inst->getDataType());
            m_writer->emit(")optixGetSbtDataPointer())");
            return true;
        }
        case kIROp_DispatchKernel:
        {
            auto dispatchInst = as<IRDispatchKernel>(inst);
            emitOperand(dispatchInst->getBaseFn(), getInfo(EmitOp::Atomic));
            m_writer->emit("<<<");
            emitOperand(dispatchInst->getThreadGroupSize(), getInfo(EmitOp::General));
            m_writer->emit(", ");
            emitOperand(dispatchInst->getDispatchSize(), getInfo(EmitOp::General));
            m_writer->emit(">>>(");
            for (UInt i = 0; i < dispatchInst->getArgCount(); i++)
            {
                if (i > 0)
                    m_writer->emit(", ");
                emitOperand(dispatchInst->getArg(i), getInfo(EmitOp::General));
            }
            m_writer->emit(")");
            return true;
        }
        default: break;
    }

    return Super::tryEmitInstExprImpl(inst, inOuterPrec);
}

void CUDASourceEmitter::handleRequiredCapabilitiesImpl(IRInst* inst)
{
    // Does this function declare any requirements on CUDA capabilities
    // that should affect output?

    for (auto decoration : inst->getDecorations())
    {
        if( auto smDecoration = as<IRRequireCUDASMVersionDecoration>(decoration))
        {
            SemanticVersion version;
            version.setFromInteger(SemanticVersion::IntegerType(smDecoration->getCUDASMVersion()));
            m_extensionTracker->requireSMVersion(version);
        }
    }
}

void CUDASourceEmitter::emitVectorTypeNameImpl(IRType* elementType, IRIntegerValue elementCount)
{
    m_writer->emit(getVectorPrefix(elementType->getOp()));
    m_writer->emit(elementCount);
}

void CUDASourceEmitter::emitSimpleTypeImpl(IRType* type)
{
    switch (type->getOp())
    {
    case kIROp_VectorType:
        {
            auto vectorType = as<IRVectorType>(type);
            m_writer->emit(getVectorPrefix(vectorType->getElementType()->getOp()));
            m_writer->emit(as<IRIntLit>(vectorType->getElementCount())->getValue());
            break;
        }
    default:
        m_writer->emit(_getTypeName(type));
        break;
    }
}

void CUDASourceEmitter::emitRateQualifiersImpl(IRRate* rate)
{
    if (as<IRGroupSharedRate>(rate))
    {
        m_writer->emit("__shared__ ");
    }
}

void CUDASourceEmitter::emitSimpleFuncParamsImpl(IRFunc* func)
{
    m_writer->emit("(");

    bool hasEmittedParam = false;
    auto firstParam = func->getFirstParam();
    for (auto pp = firstParam; pp; pp = pp->getNextParam())
    {
        auto varLayout = getVarLayout(pp);
        if (varLayout && varLayout->findSystemValueSemanticAttr())
        {
            // If it has a semantic don't output, it will be accessed via a global
            continue;
        }

        if (hasEmittedParam)
            m_writer->emit(", ");

        emitSimpleFuncParamImpl(pp);
        hasEmittedParam = true;
    }

    m_writer->emit(")");
}

void CUDASourceEmitter::emitSimpleFuncImpl(IRFunc* func)
{
    // Skip the CPP impl - as it does some processing we don't need here for entry points.
    CLikeSourceEmitter::emitSimpleFuncImpl(func);
}

void CUDASourceEmitter::emitSimpleValueImpl(IRInst* inst)
{
    // Make sure we convert float to half when emitting a half literal to avoid
    // overload ambiguity errors from CUDA.
    if (inst->getOp() == kIROp_FloatLit)
    {
        if (inst->getDataType()->getOp() == kIROp_HalfType)
        {
            m_writer->emit("__half(");
            CLikeSourceEmitter::emitSimpleValueImpl(inst);
            m_writer->emit(")");
            return;
        }
    }
    Super::emitSimpleValueImpl(inst);
}


void CUDASourceEmitter::emitSemanticsImpl(IRInst* inst, bool allowOffsetLayout)
{
    Super::emitSemanticsImpl(inst, allowOffsetLayout);
}

void CUDASourceEmitter::emitInterpolationModifiersImpl(IRInst* varInst, IRType* valueType, IRVarLayout* layout)
{
    Super::emitInterpolationModifiersImpl(varInst, valueType, layout);
}

void CUDASourceEmitter::emitVarDecorationsImpl(IRInst* varDecl)
{
    Super::emitVarDecorationsImpl(varDecl);
}

void CUDASourceEmitter::emitMatrixLayoutModifiersImpl(IRVarLayout* layout)
{
    Super::emitMatrixLayoutModifiersImpl(layout);
}

void CUDASourceEmitter::emitPreModuleImpl()
{
    SourceWriter* writer = getSourceWriter();

    // Emit generated types/functions

    writer->emit("\n");
}


bool CUDASourceEmitter::tryEmitGlobalParamImpl(IRGlobalParam* varDecl, IRType* varType)
{
    // A global shader parameter in the IR for CUDA output will
    // either be the unique constant buffer that wraps all the
    // global-scope parameters in the original code (which is
    // handled as a special-case before this routine would be
    // called), or it is one of the system-defined varying inputs
    // like `threadIdx`. We won't need to emit anything in the
    // output code for the latter case, so we need to emit
    // nothing here and return `true` so that the base class
    // uses our logic instead of the default.
    //
    SLANG_UNUSED(varDecl);
    SLANG_UNUSED(varType);
    return true;
}


void CUDASourceEmitter::emitModuleImpl(IRModule* module, DiagnosticSink* sink)
{
    CLikeSourceEmitter::emitModuleImpl(module, sink);

    // Emit all witness table definitions.
    _emitWitnessTableDefinitions();
}


} // namespace Slang