//===--------- SPIR.cpp - Emit LLVM Code for builtins ---------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This contains code to emit Builtin calls as LLVM code.
//
//===----------------------------------------------------------------------===//

#include "CGHLSLRuntime.h"
#include "CodeGenFunction.h"
#include "clang/Basic/TargetBuiltins.h"
#include "llvm/IR/Intrinsics.h"

using namespace clang;
using namespace CodeGen;
using namespace llvm;

Value *CodeGenFunction::EmitSPIRVBuiltinExpr(unsigned BuiltinID,
                                             const CallExpr *E) {
  switch (BuiltinID) {
  case SPIRV::BI__builtin_spirv_distance: {
    Value *X = EmitScalarExpr(E->getArg(0));
    Value *Y = EmitScalarExpr(E->getArg(1));
    assert(E->getArg(0)->getType()->hasFloatingRepresentation() &&
           E->getArg(1)->getType()->hasFloatingRepresentation() &&
           "Distance operands must have a float representation");
    assert(E->getArg(0)->getType()->isVectorType() &&
           E->getArg(1)->getType()->isVectorType() &&
           "Distance operands must be a vector");
    return Builder.CreateIntrinsic(
        /*ReturnType=*/X->getType()->getScalarType(), Intrinsic::spv_distance,
        ArrayRef<Value *>{X, Y}, nullptr, "spv.distance");
  }
  case SPIRV::BI__builtin_spirv_length: {
    Value *X = EmitScalarExpr(E->getArg(0));
    assert(E->getArg(0)->getType()->hasFloatingRepresentation() &&
           "length operand must have a float representation");
    assert(E->getArg(0)->getType()->isVectorType() &&
           "length operand must be a vector");
    return Builder.CreateIntrinsic(
        /*ReturnType=*/X->getType()->getScalarType(), Intrinsic::spv_length,
        ArrayRef<Value *>{X}, nullptr, "spv.length");
  }
  case SPIRV::BI__builtin_spirv_reflect: {
    Value *I = EmitScalarExpr(E->getArg(0));
    Value *N = EmitScalarExpr(E->getArg(1));
    assert(E->getArg(0)->getType()->hasFloatingRepresentation() &&
           E->getArg(1)->getType()->hasFloatingRepresentation() &&
           "Reflect operands must have a float representation");
    assert(E->getArg(0)->getType()->isVectorType() &&
           E->getArg(1)->getType()->isVectorType() &&
           "Reflect operands must be a vector");
    return Builder.CreateIntrinsic(
        /*ReturnType=*/I->getType(), Intrinsic::spv_reflect,
        ArrayRef<Value *>{I, N}, nullptr, "spv.reflect");
  }
  case SPIRV::BI__builtin_spirv_refract: {
    Value *I = EmitScalarExpr(E->getArg(0));
    Value *N = EmitScalarExpr(E->getArg(1));
    Value *eta = EmitScalarExpr(E->getArg(2));
    assert(E->getArg(0)->getType()->hasFloatingRepresentation() &&
           E->getArg(1)->getType()->hasFloatingRepresentation() &&
           E->getArg(2)->getType()->isFloatingType() &&
           "refract operands must have a float representation");
    return Builder.CreateIntrinsic(
        /*ReturnType=*/I->getType(), Intrinsic::spv_refract,
        ArrayRef<Value *>{I, N, eta}, nullptr, "spv.refract");
  }
  case SPIRV::BI__builtin_spirv_smoothstep: {
    Value *Min = EmitScalarExpr(E->getArg(0));
    Value *Max = EmitScalarExpr(E->getArg(1));
    Value *X = EmitScalarExpr(E->getArg(2));
    assert(E->getArg(0)->getType()->hasFloatingRepresentation() &&
           E->getArg(1)->getType()->hasFloatingRepresentation() &&
           E->getArg(2)->getType()->hasFloatingRepresentation() &&
           "SmoothStep operands must have a float representation");
    return Builder.CreateIntrinsic(
        /*ReturnType=*/Min->getType(), Intrinsic::spv_smoothstep,
        ArrayRef<Value *>{Min, Max, X}, /*FMFSource=*/nullptr,
        "spv.smoothstep");
  }
  case SPIRV::BI__builtin_spirv_faceforward: {
    Value *N = EmitScalarExpr(E->getArg(0));
    Value *I = EmitScalarExpr(E->getArg(1));
    Value *Ng = EmitScalarExpr(E->getArg(2));
    assert(E->getArg(0)->getType()->hasFloatingRepresentation() &&
           E->getArg(1)->getType()->hasFloatingRepresentation() &&
           E->getArg(2)->getType()->hasFloatingRepresentation() &&
           "FaceForward operands must have a float representation");
    return Builder.CreateIntrinsic(
        /*ReturnType=*/N->getType(), Intrinsic::spv_faceforward,
        ArrayRef<Value *>{N, I, Ng}, /*FMFSource=*/nullptr, "spv.faceforward");
  }
  case SPIRV::BI__builtin_spirv_generic_cast_to_ptr_explicit: {
    Value *Ptr = EmitScalarExpr(E->getArg(0));
    assert(E->getArg(0)->getType()->hasPointerRepresentation() &&
           E->getArg(1)->getType()->hasIntegerRepresentation() &&
           "GenericCastToPtrExplicit takes a pointer and an int");
    llvm::Type *Res = getTypes().ConvertType(E->getType());
    assert(Res->isPointerTy() &&
           "GenericCastToPtrExplicit doesn't return a pointer");
    llvm::CallInst *Call = Builder.CreateIntrinsicWithoutFolding(
        /*ReturnType=*/Res, Intrinsic::spv_generic_cast_to_ptr_explicit,
        ArrayRef<Value *>{Ptr}, nullptr, "spv.generic_cast");
    Call->addRetAttr(llvm::Attribute::AttrKind::NoUndef);
    return Call;
  }
  case SPIRV::BI__builtin_spirv_subgroup_shuffle: {
    Value *X = EmitScalarExpr(E->getArg(0));
    Value *Y = EmitScalarExpr(E->getArg(1));
    assert(E->getArg(1)->getType()->hasIntegerRepresentation());
    return Builder.CreateIntrinsic(
        /*ReturnType=*/getTypes().ConvertType(E->getArg(0)->getType()),
        Intrinsic::spv_wave_readlane, {X, Y}, nullptr, "spv.shuffle");
  }
  case SPIRV::BI__builtin_spirv_num_workgroups:
    return Builder.CreateIntrinsic(
        /*ReturnType=*/getTypes().ConvertType(E->getType()),
        Intrinsic::spv_num_workgroups,
        ArrayRef<Value *>{EmitScalarExpr(E->getArg(0))}, nullptr,
        "spv.num.workgroups");
  case SPIRV::BI__builtin_spirv_workgroup_size:
    return Builder.CreateIntrinsic(
        /*ReturnType=*/getTypes().ConvertType(E->getType()),
        Intrinsic::spv_workgroup_size,
        ArrayRef<Value *>{EmitScalarExpr(E->getArg(0))}, nullptr,
        "spv.workgroup.size");
  case SPIRV::BI__builtin_spirv_workgroup_id:
    return Builder.CreateIntrinsic(
        /*ReturnType=*/getTypes().ConvertType(E->getType()),
        Intrinsic::spv_group_id,
        ArrayRef<Value *>{EmitScalarExpr(E->getArg(0))}, nullptr,
        "spv.group.id");
  case SPIRV::BI__builtin_spirv_local_invocation_id:
    return Builder.CreateIntrinsic(
        /*ReturnType=*/getTypes().ConvertType(E->getType()),
        Intrinsic::spv_thread_id_in_group,
        ArrayRef<Value *>{EmitScalarExpr(E->getArg(0))}, nullptr,
        "spv.thread.id.in.group");
  case SPIRV::BI__builtin_spirv_global_invocation_id:
    return Builder.CreateIntrinsic(
        /*ReturnType=*/getTypes().ConvertType(E->getType()),
        Intrinsic::spv_thread_id,
        ArrayRef<Value *>{EmitScalarExpr(E->getArg(0))}, nullptr,
        "spv.thread.id");
  case SPIRV::BI__builtin_spirv_global_size:
    return Builder.CreateIntrinsic(
        /*ReturnType=*/getTypes().ConvertType(E->getType()),
        Intrinsic::spv_global_size,
        ArrayRef<Value *>{EmitScalarExpr(E->getArg(0))}, nullptr,
        "spv.num.workgroups");
  case SPIRV::BI__builtin_spirv_global_offset:
    return Builder.CreateIntrinsic(
        /*ReturnType=*/getTypes().ConvertType(E->getType()),
        Intrinsic::spv_global_offset,
        ArrayRef<Value *>{EmitScalarExpr(E->getArg(0))}, nullptr,
        "spv.global.offset");
  case SPIRV::BI__builtin_spirv_ddx:
    return Builder.CreateIntrinsic(
        /*ReturnType=*/getTypes().ConvertType(E->getType()), Intrinsic::spv_ddx,
        ArrayRef<Value *>{EmitScalarExpr(E->getArg(0))}, nullptr, "spv.ddx");
  case SPIRV::BI__builtin_spirv_ddy:
    return Builder.CreateIntrinsic(
        /*ReturnType=*/getTypes().ConvertType(E->getType()), Intrinsic::spv_ddy,
        ArrayRef<Value *>{EmitScalarExpr(E->getArg(0))}, nullptr, "spv.ddy");
  case SPIRV::BI__builtin_spirv_fwidth:
    return Builder.CreateIntrinsic(
        /*ReturnType=*/getTypes().ConvertType(E->getType()),
        Intrinsic::spv_fwidth, ArrayRef<Value *>{EmitScalarExpr(E->getArg(0))},
        nullptr, "spv.fwidth");
  }
  return nullptr;
}