// LLVM function pass to convert the sampler initializer calls to a target
// desired format
//
// Copyright (c) 2017 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 <set>

#include "CompilerWarnings.h"
IGNORE_COMPILER_WARNING("-Wunused-parameter")

#include "pocl.h"
#include "HandleSamplerInitialization.h"
#include "Workgroup.h"
#include "VariableUniformityAnalysis.h"

#include <llvm/IR/Instructions.h>
#include <llvm/IR/IRBuilder.h>

POP_COMPILER_DIAGS

using namespace llvm;

namespace {
  static
  RegisterPass<pocl::HandleSamplerInitialization>
  X("handle-samplers",
    "Handles sampler initialization calls.");
}

namespace pocl {

char HandleSamplerInitialization::ID = 0;

HandleSamplerInitialization::HandleSamplerInitialization() : FunctionPass(ID) {
}

bool
HandleSamplerInitialization::runOnFunction(Function &F) {

#ifdef LLVM_OLDER_THAN_4_0
  return false;
#else
  // Collect the sampler init calls to handle first, do not remove them
  // instantly as it'd invalidate the iterators.
  std::set<CallInst*> Calls;

  for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
    for (BasicBlock::iterator BI = I->begin(), BE = I->end(); BI != BE; ++BI) {
      Instruction *Instr = dyn_cast<Instruction>(BI);
      if (!llvm::isa<CallInst>(Instr)) continue;
      CallInst *CallInstr = dyn_cast<CallInst>(Instr);
      if (CallInstr->getCalledFunction() != nullptr &&
	  CallInstr->getCalledFunction()->getName() ==
	  "__translate_sampler_initializer") {
	Calls.insert(CallInstr);
      }
    }
  }

  bool Changed = false;
  for (auto C : Calls) {
    llvm::IRBuilder<> Builder(C);
    ConstantInt *SamplerValue = dyn_cast<ConstantInt>(C->arg_begin()->get());

    llvm::AllocaInst *Alloca = Builder.CreateAlloca(SamplerValue->getType());
    Builder.CreateStore(
      ConstantInt::get(SamplerValue->getType(), SamplerValue->getValue()),
      Alloca);
    C->replaceAllUsesWith(Builder.CreateBitOrPointerCast(Alloca, C->getType()));
    C->eraseFromParent();
    Changed = true;
  }
  return Changed;
#endif
}

void
HandleSamplerInitialization::getAnalysisUsage(AnalysisUsage &AU) const {
  AU.addPreserved<pocl::VariableUniformityAnalysis>();
}

}
