lib/SPIRVOp.cpp

// Copyright 2019 The Clspv Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "SPIRVOp.h"

#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Module.h"

#include "Constants.h"

namespace clspv {

using namespace llvm;

// The mangling loosely follows the Itanium convention.
// Its purpose is solely to ensure uniqueness of names, it is not
// meant to convey type information.
static std::string mangleType(Type *Ty) {
  if (auto VecTy = dyn_cast<VectorType>(Ty)) {
    auto NumVecElems = std::to_string(VecTy->getNumElements());
    return "Dv" + NumVecElems + "_" + mangleType(Ty->getScalarType());
  } else if (Ty->isIntegerTy()) {
    switch (Ty->getScalarSizeInBits()) {
    case 1:
      return "b";
    case 8:
      return "h";
    case 16:
      return "t";
    case 32:
      return "j";
    case 64:
      return "m";
    }
  } else if (Ty->isFloatingPointTy()) {
    switch (Ty->getScalarSizeInBits()) {
    case 16:
      return "Dh";
    case 32:
      return "f";
    case 64:
      return "d";
    }
  } else if (Ty->isPointerTy()) {
    auto PtrTy = cast<PointerType>(Ty);
    auto AS = std::to_string(PtrTy->getAddressSpace());
    return "P" + AS + mangleType(PtrTy->getElementType());
  }

  llvm_unreachable("Unhandled type in SPIR-V intrinsic name mangler");
}

Instruction *InsertSPIRVOp(Instruction *Insert, spv::Op Opcode,
                           ArrayRef<Attribute::AttrKind> Attributes,
                           Type *RetType, ArrayRef<Value *> Args) {

  // Prepare mangled name
  std::string MangledName = clspv::SPIRVOpIntrinsicFunction();
  MangledName += std::to_string(Opcode);
  MangledName += ".";
  for (auto Arg : Args) {
    MangledName += mangleType(Arg->getType());
  }

  // Create a function in the module
  auto M = Insert->getModule();
  auto Int32Ty = Type::getInt32Ty(M->getContext());
  SmallVector<Type *, 8> ArgTypes = {Int32Ty};
  for (auto Arg : Args) {
    ArgTypes.push_back(Arg->getType());
  }
  auto NewFType = FunctionType::get(RetType, ArgTypes, false);
  auto NewFTyC = M->getOrInsertFunction(MangledName, NewFType);
  auto NewF = cast<Function>(NewFTyC.getCallee());
  for (auto A : Attributes) {
    NewF->addFnAttr(A);
  }

  // Now call it with the values we were passed
  SmallVector<Value *, 8> ArgValues = {ConstantInt::get(Int32Ty, Opcode)};
  for (auto Arg : Args) {
    ArgValues.push_back(Arg);
  }

  return CallInst::Create(NewF, ArgValues, "", Insert);
}

}; // namespace clspv