// Copyright 2018 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 <vector>

#include "llvm/IR/CallingConv.h"
#include "llvm/IR/Instructions.h"
#include "llvm/Pass.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/Cloning.h"

#include "clspv/AddressSpace.h"
#include "clspv/Option.h"

#include "BitcastUtils.h"
#include "InlineEntryPointsPass.h"

using namespace llvm;

PreservedAnalyses clspv::InlineEntryPointsPass::run(Module &M,
                                                    ModuleAnalysisManager &) {
  PreservedAnalyses PA;
  if (!RequiresInlining(M))
    return PA;


  bool changed = true;
  while (changed) {
    changed &= InlineFunctions(M);
  }

  return PA;
}

bool clspv::InlineEntryPointsPass::InlineFunctions(Module &M) {
  bool Changed = false;
  std::vector<CallInst *> to_inline;
  for (auto &F : M) {
    if (F.isDeclaration() || F.getCallingConv() == CallingConv::SPIR_KERNEL)
      continue;

    for (auto user : F.users()) {
      if (auto call = dyn_cast<CallInst>(user))
        to_inline.push_back(call);
    }
  }

  for (auto call : to_inline) {
    InlineFunctionInfo IFI;
    // Disable generation of lifetime intrinsic.
    Changed |= InlineFunction(*call, IFI, false, nullptr, false).isSuccess();
  }

  return Changed;
}

bool clspv::InlineEntryPointsPass::RequiresInlining(Module &M) {
  if (clspv::Option::InlineEntryPoints())
    return true;

  auto HasGeneric = [](const Type *ty) {
    if (ty->isPointerTy() &&
        ty->getPointerAddressSpace() == clspv::AddressSpace::Generic)
      return true;
    return false;
  };

  for (auto &F : M) {
    // Remove constant expressions to find the generic address space more
    // easily. This is also useful throughout the flow.
    BitcastUtils::RemoveCstExprFromFunction(&F);

    auto f_ty = F.getFunctionType();
    for (auto *p_ty : f_ty->params()) {
      if (HasGeneric(p_ty))
        return true;
    }
    for (auto &BB : F) {
      for (auto &I : BB) {
        if (HasGeneric(I.getType()))
          return true;
        for (auto *op : I.operand_values()) {
          if (HasGeneric(op->getType()))
            return true;
        }
      }
    }
  }

  return false;
}