// Implementation of LLVMUtils, useful common LLVM-related functionality.
// 
// Copyright (c) 2013 Pekka Jääskeläinen / TUT
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#include "LLVMUtils.h"

#include "pocl_spir.h"

#include <llvm/IR/Instructions.h>
#include <llvm/IR/Module.h>
#include <llvm/IR/Metadata.h>

using namespace llvm;

namespace pocl {

/**
 * Regenerates the metadata that points to the original kernel
 * (of which finger print was modified) to point to the new
 * kernel.
 *
 * Only checks if the first operand of the metadata is the kernel
 * function.
 */
void
regenerate_kernel_metadata(llvm::Module &M, FunctionMapping &kernels)
{
  // reproduce the opencl.kernel_wg_size_info metadata
  NamedMDNode *wg_sizes = M.getNamedMetadata("opencl.kernel_wg_size_info");
  if (wg_sizes != NULL && wg_sizes->getNumOperands() > 0) 
    {
      for (std::size_t mni = 0; mni < wg_sizes->getNumOperands(); ++mni)
        {
          MDNode *wgsizeMD = dyn_cast<MDNode>(wg_sizes->getOperand(mni));
          for (FunctionMapping::const_iterator i = kernels.begin(),
                 e = kernels.end(); i != e; ++i) 
            {
              Function *old_kernel = (*i).first;
              Function *new_kernel = (*i).second;
              Function *func_from_md;
              func_from_md = dyn_cast<Function>(
                dyn_cast<ValueAsMetadata>(wgsizeMD->getOperand(0))->getValue());
              if (old_kernel == new_kernel || wgsizeMD->getNumOperands() == 0 ||
                  func_from_md != old_kernel) 
                continue;
              // found a wg size metadata that points to the old kernel, copy its
              // operands except the first one to a new MDNode
              SmallVector<Metadata*, 8> operands;
              operands.push_back(llvm::ValueAsMetadata::get(new_kernel));
              for (unsigned opr = 1; opr < wgsizeMD->getNumOperands(); ++opr) {
                  operands.push_back(wgsizeMD->getOperand(opr));
              }
              MDNode *new_wg_md = MDNode::get(M.getContext(), operands);
              wg_sizes->addOperand(new_wg_md);
            }
        }
    }

  // reproduce the opencl.kernels metadata, if it exists
  // unconditionally adding opencl.kernels confuses the
  // metadata parser in pocl_llvm_metadata.cc, which uses
  // "opencl.kernels" to distinguish old SPIR format from new
  NamedMDNode *nmd = M.getNamedMetadata("opencl.kernels");
  if (nmd) {
    M.eraseNamedMetadata(nmd);

    nmd = M.getOrInsertNamedMetadata("opencl.kernels");
    for (FunctionMapping::const_iterator i = kernels.begin(),
         e = kernels.end();
       i != e; ++i) {
      MDNode *md = MDNode::get(M.getContext(), ArrayRef<Metadata *>(
        llvm::ValueAsMetadata::get((*i).second)));
      nmd->addOperand(md);
    }
  }

}

void eraseFunctionAndCallers(llvm::Function *Function) {
  if (!Function)
    return;

  std::vector<llvm::Value *> Callers(Function->user_begin(),
                                     Function->user_end());
  for (auto &U : Callers) {
    llvm::CallInst *Call = llvm::dyn_cast<llvm::CallInst>(U);
    if (!Call)
      continue;
    Call->eraseFromParent();
  }
  Function->eraseFromParent();
}

}
