//===- SPLInstrScheduling.cpp - Modulo Software Pipelining Instruction Scheduling support -------===//
//
// this file implements the llvm/CodeGen/ModuloScheduling.h interface
//
//
//===----------------------------------------------------------------------===//

#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineCodeForInstruction.h"
#include "llvm/CodeGen/MachineCodeForBasicBlock.h"
#include "llvm/CodeGen/MachineCodeForMethod.h"
#include "llvm/Analysis/LiveVar/FunctionLiveVarInfo.h" // FIXME: Remove when modularized better
#include "llvm/Target/TargetMachine.h"
#include "llvm/BasicBlock.h"
#include "llvm/Instruction.h"
#include "Support/CommandLine.h"
#include <algorithm>
#include "ModuloSchedGraph.h"
#include "ModuloScheduling.h"
#include "llvm/Target/MachineSchedInfo.h"
#include "llvm/BasicBlock.h"
#include "llvm/iTerminators.h"
#include "llvm/iPHINode.h"
#include "llvm/Constants.h"
#include <iostream>
#include <swig.h>
#include <fstream>
#include "llvm/CodeGen/InstrSelection.h"

#define max(x,y) (x>y?x:y)
#define min(x,y) (x<y?x:y)
using std::cerr;
using std::cout;
using std::ostream;
using std::ios;
using std::filebuf;

//************************************************************
//printing Debug information
//ModuloSchedDebugLevel stores the value of debug level
// modsched_os is the ostream to dump debug information, which is written into the file 'moduloSchedDebugInfo.output'
//see ModuloSchedulingPass::runOnFunction()
//************************************************************

ModuloSchedDebugLevel_t ModuloSchedDebugLevel;
static cl::opt<ModuloSchedDebugLevel_t, true>
SDL_opt("modsched", cl::Hidden, cl::location(ModuloSchedDebugLevel),
        cl::desc("enable modulo scheduling debugging information"),
        cl::values(
 clEnumValN(ModuloSched_NoDebugInfo,      "n", "disable debug output"),
 clEnumValN(ModuloSched_Disable,        "off", "disable modulo scheduling"),
 clEnumValN(ModuloSched_PrintSchedule,  "psched", "print original and new schedule"),
 clEnumValN(ModuloSched_PrintScheduleProcess,"pschedproc", "print how the new schdule is produced"),
                   0));

filebuf modSched_fb;
ostream modSched_os(&modSched_fb);

//************************************************************


///the method to compute schedule and instert epilogue and prologue
void ModuloScheduling::instrScheduling(){
  
  if( ModuloSchedDebugLevel >= ModuloSched_PrintScheduleProcess)
    modSched_os<<"*************************computing modulo schedule ************************\n";
  
  
  const MachineSchedInfo& msi=target.getSchedInfo();

  //number of issue slots in the in each cycle
  int numIssueSlots=msi.maxNumIssueTotal;



  //compute the schedule
  bool success=false;
  while(!success)
    {
      //clear memory from the last round and initialize if necessary
      clearInitMem(msi);

      //compute schedule and coreSchedule with the current II
      success=computeSchedule();
      
      if(!success){
	II++;
	if( ModuloSchedDebugLevel >= ModuloSched_PrintScheduleProcess)
	  modSched_os<<"increase II  to "<<II<<"\n";
      }
    }
  
  //print the final schedule if necessary
  if( ModuloSchedDebugLevel >= ModuloSched_PrintSchedule)
    dumpScheduling();
  

  //the schedule has been computed
  //create epilogue, prologue and kernel BasicBlock
 
  //find the successor for this BasicBlock
  BasicBlock* succ_bb= getSuccBB(bb); 
  
  //print the original BasicBlock if necessary
  if( ModuloSchedDebugLevel >= ModuloSched_PrintSchedule){
    modSched_os<<"dumping the orginal block\n";  
    graph.dump(bb);
  }

  //construction of prologue, kernel and epilogue
  BasicBlock* kernel=bb->splitBasicBlock(bb->begin());
  BasicBlock* prologue= bb;
  BasicBlock* epilogue=kernel->splitBasicBlock(kernel->begin());
  
  
  //construct prologue
  constructPrologue(prologue);

  //construct kernel
  constructKernel(prologue,kernel,epilogue);

  //construct epilogue
  constructEpilogue(epilogue,succ_bb);

 
  //print the BasicBlocks if necessary
  if( ModuloSchedDebugLevel >= ModuloSched_PrintSchedule){
    modSched_os<<"dumping the prologue block:\n";
    graph.dump(prologue);
    modSched_os<<"dumping the kernel block\n";
    graph.dump(kernel);
    modSched_os<<"dumping the epilogue block\n";
    graph.dump(epilogue);
  }
  
}    

//clear memory from the last round and initialize if necessary
void ModuloScheduling::clearInitMem(const MachineSchedInfo& msi){
  

  unsigned numIssueSlots = msi.maxNumIssueTotal;
  //clear nodeScheduled from the last round
  if( ModuloSchedDebugLevel >= ModuloSched_PrintScheduleProcess){
    modSched_os<< "***** new round  with II= "<<II<<" *******************"<<endl;
    modSched_os<< " **************clear the vector nodeScheduled**************** \n";
  }
  nodeScheduled.clear();
  
  
  //clear resourceTable from the last round and reset it 
  resourceTable.clear();
  for(unsigned i=0;i< II;i++)
    resourceTable.push_back(msi.resourceNumVector);
  
  
  //clear the schdule and coreSchedule from the last round 
  schedule.clear();
  coreSchedule.clear();
  
  //create a coreSchedule of size II*numIssueSlots
  //each entry is NULL
  while( coreSchedule.size() <  II){
    std::vector<ModuloSchedGraphNode*>* newCycle=new  std::vector<ModuloSchedGraphNode*>();
    for(unsigned k=0;k<numIssueSlots;k++)
      newCycle->push_back(NULL);
    coreSchedule.push_back(*newCycle);
  }  
}


//compute schedule and coreSchedule with the current II
bool ModuloScheduling::computeSchedule(){
  
  if( ModuloSchedDebugLevel >= ModuloSched_PrintScheduleProcess)
    modSched_os <<"start to compute schedule \n";
  
  //loop over the ordered nodes
  for(NodeVec::const_iterator I=oNodes.begin();I!=oNodes.end();I++)
    {
      //try to schedule for node I
      if( ModuloSchedDebugLevel >= ModuloSched_PrintScheduleProcess)
	dumpScheduling();
      ModuloSchedGraphNode* node=*I;

      //compute whether this node has successor(s)
      bool succ=true;

      //compute whether this node has predessor(s)
      bool pred=true;

      NodeVec schSucc=graph.vectorConj(nodeScheduled,graph.succSet(node));
      if(schSucc.empty())
	succ=false;
      NodeVec schPred=graph.vectorConj(nodeScheduled,graph.predSet(node));   
      if(schPred.empty())
	pred=false;
      
      //startTime: the earliest time we will try to schedule this node
      //endTime: the latest time we will try to schedule this node
      int startTime, endTime;

      //node's earlyStart: possible earliest time to schedule this node
      //node's lateStart: possible latest time to schedule this node
      node->setEarlyStart(-1);
      node->setLateStart(9999);
      

      //this node has predessor but no successor
      if(!succ && pred){

	//this node's earlyStart is it's predessor's schedule time + the edge delay 
	// - the iteration difference* II    
	for(unsigned i=0;i<schPred.size();i++){
	  ModuloSchedGraphNode* predNode=schPred[i];
	  SchedGraphEdge* edge=graph.getMaxDelayEdge(predNode->getNodeId(),node->getNodeId());
	  int temp=predNode->getSchTime()+edge->getMinDelay() - edge->getIteDiff()*II;
	  node->setEarlyStart( max(node->getEarlyStart(),temp));
	}
	startTime=node->getEarlyStart();
	endTime=node->getEarlyStart()+II-1;
      }
      

      //this node has successor but no predessor
      if(succ && !pred){
	for(unsigned i=0;i<schSucc.size();i++){
	  ModuloSchedGraphNode* succNode=schSucc[i];
	  SchedGraphEdge* edge=graph.getMaxDelayEdge(succNode->getNodeId(),node->getNodeId());
	  int temp=succNode->getSchTime() - edge->getMinDelay() + edge->getIteDiff()*II;
	  node->setLateStart(min(node->getEarlyStart(),temp));
	}
	startTime=node->getLateStart()- II+1;
	endTime=node->getLateStart();
      }

      //this node has both successors and predessors
      if(succ && pred)
	{
	  for(unsigned i=0;i<schPred.size();i++){
	    ModuloSchedGraphNode* predNode=schPred[i];
	    SchedGraphEdge* edge=graph.getMaxDelayEdge(predNode->getNodeId(),node->getNodeId());
	    int temp=predNode->getSchTime()+edge->getMinDelay() - edge->getIteDiff()*II;
	    node->setEarlyStart(max(node->getEarlyStart(),temp));
	  }
	  for(unsigned i=0;i<schSucc.size();i++){
	    ModuloSchedGraphNode* succNode=schSucc[i];
	    SchedGraphEdge* edge=graph.getMaxDelayEdge(succNode->getNodeId(),node->getNodeId());
	    int temp=succNode->getSchTime() - edge->getMinDelay() + edge->getIteDiff()*II;
	    node->setLateStart(min(node->getEarlyStart(),temp));
	  }
	  startTime=node->getEarlyStart();
	  endTime=min(node->getLateStart(),node->getEarlyStart()+((int)II)-1);
	}
      
      //this node has no successor or predessor
      if(!succ && !pred){
	node->setEarlyStart(node->getASAP());
	startTime=node->getEarlyStart();
	endTime=node->getEarlyStart()+II -1;
      }

      //try to schedule this node based on the startTime and endTime
      if( ModuloSchedDebugLevel >= ModuloSched_PrintScheduleProcess)
	modSched_os<<"scheduling the node "<<(*I)->getNodeId()<<"\n";      

      bool success= this->ScheduleNode(node,startTime, endTime,nodeScheduled);
      if(!success)return false;
    }
  return true;
}


//get the successor of the BasicBlock
BasicBlock* ModuloScheduling::getSuccBB(BasicBlock* bb){

  BasicBlock* succ_bb;
  for(unsigned i=0;i < II; i++)
    for(unsigned j=0;j< coreSchedule[i].size();j++)
      if(coreSchedule[i][j]){
	const Instruction* ist=coreSchedule[i][j]->getInst();
	
	//we can get successor from the BranchInst instruction
	//assume we only have one successor (besides itself) here
	if(BranchInst::classof(ist)){
	  BranchInst* bi=(BranchInst*)ist;
	  assert(bi->isConditional()&&"the branchInst is not a conditional one");
	  assert(bi->getNumSuccessors() ==2&&" more than two successors?");
	  BasicBlock* bb1=bi->getSuccessor(0);
	  BasicBlock* bb2=bi->getSuccessor(1);
	  assert( (bb1 ==  bb|| bb2 == bb) && " None of its successor is itself?");
	  if(bb1 == bb) succ_bb=bb2;
	  else succ_bb=bb1;
	  return succ_bb;
	}
      }
  assert( 0 && "NO Successor?");
  return NULL;
}


//get the predecessor of the BasicBlock
BasicBlock* ModuloScheduling::getPredBB(BasicBlock* bb){

  BasicBlock* pred_bb;

  for(unsigned i=0;i < II; i++)
    for(unsigned j=0;j< coreSchedule[i].size();j++)
      if(coreSchedule[i][j]){
	const Instruction* ist=coreSchedule[i][j]->getInst();
	
	//we can get predecessor from the PHINode instruction
	//assume we only have one predecessor (besides itself) here
	if(PHINode::classof(ist)){
	  PHINode* phi=(PHINode*) ist;
	  assert(phi->getNumIncomingValues() == 2 &&" the number of incoming value is not equal to two? ");
	  BasicBlock* bb1= phi->getIncomingBlock(0);
	  BasicBlock* bb2= phi->getIncomingBlock(1);
	  assert( (bb1 ==  bb || bb2 == bb) && " None of its predecessor is itself?");
	  if(bb1 == bb) pred_bb=bb2;
	  else pred_bb=bb1;	  
	  return pred_bb;
	}
      }
  assert(0 && " no predecessor?");
  return NULL;
}


//construct the prologue
void ModuloScheduling::constructPrologue(BasicBlock* prologue){
  
  InstListType& prologue_ist = prologue->getInstList();
  vvNodeType& tempSchedule_prologue= *(new vector< std::vector<ModuloSchedGraphNode*> >(schedule));
  
  //compute the schedule for prologue
  unsigned round=0;
  unsigned scheduleSize=schedule.size();
  while(round < scheduleSize/II){
    round++;
    for(unsigned i=0;i < scheduleSize ;i++){
      if(round*II + i >= scheduleSize) break;
      for(unsigned j=0;j < schedule[i].size(); j++) 
	if(schedule[i][j]){
	  assert( tempSchedule_prologue[round*II +i ][j] == NULL && "table not consitant with core table");
	  
	  //move  the schedule one iteration ahead and overlap with the original one
	  tempSchedule_prologue[round*II + i][j]=schedule[i][j];
	}
    }
  }

  //clear the clone memory in the core schedule instructions
  clearCloneMemory();
  
  //fill in the prologue
  for(unsigned i=0;i < ceil(1.0*scheduleSize/II -1)*II ;i++)
    for(unsigned j=0;j < tempSchedule_prologue[i].size();j++)
      if(tempSchedule_prologue[i][j]){

	//get the instruction
	Instruction* orn=(Instruction*)tempSchedule_prologue[i][j]->getInst();

	//made a clone of it
	Instruction* cln=cloneInstSetMemory(orn);

	//insert the instruction
	prologue_ist.insert(prologue_ist.back(),cln );

	//if there is PHINode in the prologue, the incoming value from itself should be removed
	//because it is not a loop any longer
	if( PHINode::classof(cln)){
	  PHINode* phi=(PHINode*)cln;
	  phi->removeIncomingValue(phi->getParent());
	}
      }
}


//construct the kernel BasicBlock
void ModuloScheduling::constructKernel(BasicBlock* prologue,BasicBlock* kernel,BasicBlock* epilogue){

  //*************fill instructions in the kernel****************
  InstListType& kernel_ist   = kernel->getInstList();
  BranchInst* brchInst;
  PHINode* phiInst, *phiCln;

  for(unsigned i=0;i<coreSchedule.size();i++)
    for(unsigned j=0;j<coreSchedule[i].size();j++)
      if(coreSchedule[i][j]){
	
	//we should take care of branch instruction differently with normal instructions
	if(BranchInst::classof(coreSchedule[i][j]->getInst())){
	  brchInst=(BranchInst*)coreSchedule[i][j]->getInst();
	  continue;
	}
	
	//we should take care of PHINode instruction differently with normal instructions
	if( PHINode::classof(coreSchedule[i][j]->getInst())){
	  phiInst= (PHINode*)coreSchedule[i][j]->getInst();
	  Instruction* cln=cloneInstSetMemory(phiInst);
	  kernel_ist.insert(kernel_ist.back(),cln);
	  phiCln=(PHINode*)cln;
	  continue;
	}
	
	//for normal instructions: made a clone and insert it in the kernel_ist
	Instruction* cln=cloneInstSetMemory( (Instruction*)coreSchedule[i][j]->getInst());
	kernel_ist.insert(kernel_ist.back(),cln);
      }

  //the two incoming BasicBlock for PHINode is the prologue and the kernel (itself)
  phiCln->setIncomingBlock(0,prologue);
  phiCln->setIncomingBlock(1,kernel);

  //the incoming value for the kernel (itself) is the new value which is computed in the kernel
  Instruction* originalVal=(Instruction*)phiInst->getIncomingValue(1);
  phiCln->setIncomingValue(1, originalVal->getClone());
  

  //make a clone of the branch instruction and insert it in the end
  BranchInst* cln=(BranchInst*)cloneInstSetMemory( brchInst);
  kernel_ist.insert(kernel_ist.back(),cln);

  //delete the unconditional branch instruction, which is generated when splitting the basicBlock
  kernel_ist.erase( --kernel_ist.end());

  //set the first successor to itself
  ((BranchInst*)cln)->setSuccessor(0, kernel);
  //set the second successor to eiplogue
  ((BranchInst*)cln)->setSuccessor(1,epilogue);

  //*****change the condition*******

  //get the condition instruction
  Instruction* cond=(Instruction*)cln->getCondition();

  //get the condition's second operand, it should be a constant
  Value* operand=cond->getOperand(1);
  assert(ConstantSInt::classof(operand));

  //change the constant in the condtion instruction
  ConstantSInt* iteTimes=ConstantSInt::get(operand->getType(),((ConstantSInt*)operand)->getValue()-II+1);
  cond->setOperand(1,iteTimes);

}





//construct the epilogue 
void ModuloScheduling::constructEpilogue(BasicBlock* epilogue, BasicBlock* succ_bb){
  
  //compute the schedule for epilogue
  vvNodeType& tempSchedule_epilogue= *(new vector< std::vector<ModuloSchedGraphNode*> >(schedule));
  unsigned scheduleSize=schedule.size();
  int round =0;
  while(round < ceil(1.0*scheduleSize/II )-1 ){
    round++;
    for( unsigned i=0;i < scheduleSize ; i++){
      if(i + round *II >= scheduleSize) break;
      for(unsigned j=0;j < schedule[i].size();j++)
	if(schedule[i + round*II ][j]){
	  assert( tempSchedule_epilogue[i][j] == NULL && "table not consitant with core table");

	  //move the schdule one iteration behind and overlap
	  tempSchedule_epilogue[i][j]=schedule[i + round*II][j];
	}
    }
  }
  
  //fill in the epilogue
  InstListType& epilogue_ist = epilogue->getInstList();
  for(unsigned i=II;i <scheduleSize ;i++)
    for(unsigned j=0;j < tempSchedule_epilogue[i].size();j++)
      if(tempSchedule_epilogue[i][j]){
	Instruction* inst=(Instruction*)tempSchedule_epilogue[i][j]->getInst();

	//BranchInst and PHINode should be treated differently
	//BranchInst:unecessary, simly omitted
	//PHINode: omitted
	if( !BranchInst::classof(inst) && ! PHINode::classof(inst) ){
	  //make a clone instruction and insert it into the epilogue
	  Instruction* cln=cloneInstSetMemory(inst);	
	  epilogue_ist.push_front(cln);
	}
      }


  //*************delete the original instructions****************//
  //to delete the original instructions, we have to make sure their use is zero
  
  //update original core instruction's uses, using its clone instread
  for(unsigned i=0;i < II; i++)
    for(unsigned j=0;j < coreSchedule[i].size() ;j++){
      if(coreSchedule[i][j])
	updateUseWithClone((Instruction*)coreSchedule[i][j]->getInst() );
    }
  
  //erase these instructions
  for(unsigned i=0;i < II; i++)
    for(unsigned j=0;j < coreSchedule[i].size();j++)
      if(coreSchedule[i][j]){
	Instruction* ist=(Instruction*)coreSchedule[i][j]->getInst();
	ist->getParent()->getInstList().erase(ist);
      }
  //**************************************************************//


  //finally, insert an unconditional branch instruction at the end
  epilogue_ist.push_back(new BranchInst(succ_bb));
  
}


//----------------------------------------------------------------------------------------------
//this function replace the value(instruction) ist in other instructions with its latest clone
//i.e. after this function is called, the ist is not used anywhere and it can be erased.
//----------------------------------------------------------------------------------------------
void ModuloScheduling::updateUseWithClone(Instruction* ist){
  
  while(ist->use_size() >0){
    bool destroyed=false;
    
    //other instruction is using this value ist
    assert(Instruction::classof(*ist->use_begin()));
    Instruction *inst=(Instruction*)(* ist->use_begin());

    for(unsigned i=0;i<inst->getNumOperands();i++)
      if(inst->getOperand(i) == ist && ist->getClone()){

	//if the instruction is TmpInstruction, simly delete it because it has no parent
	// and it does not belongs to any BasicBlock
	if(TmpInstruction::classof(inst)) {
	  delete inst;
	  destroyed=true;
	  break;
	}


	//otherwise, set the instruction's operand to the value's clone
	inst->setOperand(i, ist->getClone());

	//the use from the original value ist is destroyed
	destroyed=true;
	break;
      }
    if( !destroyed)
      {
	//if the use can not be destroyed , something is wrong
	inst->dump();
	assert( 0  &&"this use can not be destroyed"); 
      }
  }
  
}


//********************************************************
//this function clear all clone mememoy
//i.e. set all instruction's clone memory to NULL
//*****************************************************
void ModuloScheduling::clearCloneMemory(){
for(unsigned i=0; i < coreSchedule.size();i++)
  for(unsigned j=0;j<coreSchedule[i].size();j++)
    if(coreSchedule[i][j]) ((Instruction*)coreSchedule[i][j]->getInst())->clearClone();
 
}


//********************************************************************************
//this function make a clone of the instruction orn
//the cloned instruction will use the orn's operands' latest clone as its operands
//it is done this way because LLVM is in SSA form and we should use the correct value
//
//this fuction also update the instruction orn's latest clone memory
//**********************************************************************************
Instruction*  ModuloScheduling::cloneInstSetMemory(Instruction* orn) {

//make a clone instruction
  Instruction* cln=orn->clone();
  

  //update the operands
  for(unsigned k=0;k<orn->getNumOperands();k++){
    const Value* op=orn->getOperand(k);
    if(Instruction::classof(op) && ((Instruction*)op)->getClone()){      
      Instruction* op_inst=(Instruction*)op;
      cln->setOperand(k, op_inst->getClone());
    }
  }

  //update clone memory
  orn->setClone(cln);
  return cln;
}



bool ModuloScheduling::ScheduleNode(ModuloSchedGraphNode* node,unsigned start, unsigned end, NodeVec& nodeScheduled)
{
  
  const MachineSchedInfo& msi=target.getSchedInfo();
  unsigned int numIssueSlots=msi.maxNumIssueTotal;

  if( ModuloSchedDebugLevel >= ModuloSched_PrintScheduleProcess)
    modSched_os<<"startTime= "<<start<<" endTime= "<<end<<"\n";
  bool isScheduled=false;
  for(unsigned i=start;i<= end;i++){
    if( ModuloSchedDebugLevel >= ModuloSched_PrintScheduleProcess)
      modSched_os<< " now try cycle " <<i<<":"<<"\n"; 
    for(unsigned j=0;j<numIssueSlots;j++){
      unsigned int core_i = i%II;
      unsigned int core_j=j;
      if( ModuloSchedDebugLevel >= ModuloSched_PrintScheduleProcess)
	modSched_os <<"\t Trying slot "<<j<<"...........";
      //check the resouce table, make sure there is no resource conflicts
      const Instruction* instr=node->getInst();
      MachineCodeForInstruction& tempMvec=  MachineCodeForInstruction::get(instr);
      bool resourceConflict=false;
      const MachineInstrInfo &mii=msi.getInstrInfo();
      
      if(coreSchedule.size() < core_i+1 || !coreSchedule[core_i][core_j]){
	//this->dumpResourceUsageTable();
	int latency=0;
	for(unsigned k=0;k< tempMvec.size();k++)
	  {
	    MachineInstr* minstr=tempMvec[k];
	    InstrRUsage rUsage=msi.getInstrRUsage(minstr->getOpCode());
	    std::vector<std::vector<resourceId_t> > resources
	      =rUsage.resourcesByCycle;
	    updateResourceTable(resources,i + latency);
	    latency +=max(mii.minLatency(minstr->getOpCode()),1) ;
	  }
	
	//this->dumpResourceUsageTable();
	
	latency=0;
	if( resourceTableNegative()){
	  
	  //undo-update the resource table
	  for(unsigned k=0;k< tempMvec.size();k++){
	    MachineInstr* minstr=tempMvec[k];
	    InstrRUsage rUsage=msi.getInstrRUsage(minstr->getOpCode());
	    std::vector<std::vector<resourceId_t> > resources
	      =rUsage.resourcesByCycle;
	    undoUpdateResourceTable(resources,i + latency);
	    latency +=max(mii.minLatency(minstr->getOpCode()),1) ;
	  }
	  resourceConflict=true;
	}
      }
      if( !resourceConflict &&  !coreSchedule[core_i][core_j]){
	if( ModuloSchedDebugLevel >= ModuloSched_PrintScheduleProcess){
	  modSched_os <<" OK!"<<"\n";
	  modSched_os<<"Node "<<node->getNodeId()<< " is scheduleed."<<"\n";
	}
	//schedule[i][j]=node;
	while(schedule.size() <= i){
	  std::vector<ModuloSchedGraphNode*>* newCycle=new  std::vector<ModuloSchedGraphNode*>();
	  for(unsigned  k=0;k<numIssueSlots;k++)
	    newCycle->push_back(NULL);
	  schedule.push_back(*newCycle);
	}
	vector<ModuloSchedGraphNode*>::iterator startIterator;
	startIterator = schedule[i].begin();
	schedule[i].insert(startIterator+j,node);
	startIterator = schedule[i].begin();
	schedule[i].erase(startIterator+j+1);

	//update coreSchedule
	//coreSchedule[core_i][core_j]=node;
	while(coreSchedule.size() <= core_i){
	  std::vector<ModuloSchedGraphNode*>* newCycle=new  std::vector<ModuloSchedGraphNode*>();
	  for(unsigned k=0;k<numIssueSlots;k++)
	    newCycle->push_back(NULL);
	  coreSchedule.push_back(*newCycle);
	}

	startIterator = coreSchedule[core_i].begin();
	coreSchedule[core_i].insert(startIterator+core_j,node);
	startIterator = coreSchedule[core_i].begin();
	coreSchedule[core_i].erase(startIterator+core_j+1);

	node->setSchTime(i);
	isScheduled=true;
	nodeScheduled.push_back(node);
	
	break;
      }
      else if( coreSchedule[core_i][core_j]) {
	if( ModuloSchedDebugLevel >= ModuloSched_PrintScheduleProcess)
	  modSched_os <<" Slot not available "<<"\n";
      }
      else{
	if( ModuloSchedDebugLevel >= ModuloSched_PrintScheduleProcess)
	  modSched_os <<" Resource conflicts"<<"\n";
      }
    }
    if(isScheduled) break;
  }
  //assert(nodeScheduled &&"this node can not be scheduled?");
  return isScheduled;
}

void ModuloScheduling::updateResourceTable(std::vector<std::vector<unsigned int> > useResources, int startCycle){
  for(unsigned i=0;i< useResources.size();i++){
    int absCycle=startCycle+i;
    int coreCycle=absCycle % II;
    std::vector<pair<int,int> >& resourceRemained=resourceTable[coreCycle];
    std::vector<unsigned int>& resourceUsed= useResources[i];
    for(unsigned j=0;j< resourceUsed.size();j++){
      for(unsigned k=0;k< resourceRemained.size();k++)
	if((int)resourceUsed[j] == resourceRemained[k].first){
	  resourceRemained[k].second--;
	}
    }
  }
}

void ModuloScheduling::undoUpdateResourceTable(std::vector<std::vector<unsigned int> > useResources, int startCycle){
  for(unsigned i=0;i< useResources.size();i++){
    int absCycle=startCycle+i;
    int coreCycle=absCycle % II;
    std::vector<pair<int,int> >& resourceRemained=resourceTable[coreCycle];
    std::vector<unsigned int>& resourceUsed= useResources[i];
    for(unsigned j=0;j< resourceUsed.size();j++){
      for(unsigned k=0;k< resourceRemained.size();k++)
	if((int)resourceUsed[j] == resourceRemained[k].first){
	  resourceRemained[k].second++;
	}
    }
  }
}


//-----------------------------------------------------------------------
//Function: resouceTableNegative
//return value:
//          return false if any element in the resouceTable is negative
//          otherwise return true
//Purpose:
//          this function is used to determine if an instruction is eligible for schedule at certain cycle
//---------------------------------------------------------------------------------------

bool ModuloScheduling::resourceTableNegative(){
  assert(resourceTable.size() == (unsigned)II&& "resouceTable size must be equal to II");
  bool isNegative=false;
  for(unsigned i=0; i < resourceTable.size();i++)
    for(unsigned j=0;j < resourceTable[i].size();j++){
      if(resourceTable[i][j].second <0) {
	isNegative=true;
	break;
      } 
    }
  return isNegative;
}


//----------------------------------------------------------------------
//Function: dumpResouceUsageTable
//Purpose:
//          print out ResouceTable for debug
//
//------------------------------------------------------------------------

void ModuloScheduling::dumpResourceUsageTable(){
  modSched_os<<"dumping resource usage table"<<"\n";
  for(unsigned i=0;i< resourceTable.size();i++){
    for(unsigned j=0;j < resourceTable[i].size();j++)
      modSched_os <<resourceTable[i][j].first<<":"<< resourceTable[i][j].second<<" ";
    modSched_os <<"\n";
  }
  
}

//----------------------------------------------------------------------
//Function: dumpSchedule
//Purpose:
//       print out thisSchedule for debug
//
//-----------------------------------------------------------------------
void ModuloScheduling::dumpSchedule(std::vector< std::vector<ModuloSchedGraphNode*> > thisSchedule){
  
  const MachineSchedInfo& msi=target.getSchedInfo();
  unsigned numIssueSlots=msi.maxNumIssueTotal;
  for(unsigned i=0;i< numIssueSlots;i++)
      modSched_os <<"\t#";
  modSched_os<<"\n";
  for(unsigned i=0;i < thisSchedule.size();i++)
    {
      modSched_os<<"cycle"<<i<<": ";
      for(unsigned j=0;j<thisSchedule[i].size();j++)
	if(thisSchedule[i][j]!= NULL)
	  modSched_os<<thisSchedule[i][j]->getNodeId()<<"\t";
	else
	  modSched_os<<"\t";
      modSched_os<<"\n";
    }

}


//----------------------------------------------------
//Function: dumpScheduling
//Purpose:
//   print out the schedule and coreSchedule for debug      
//
//-------------------------------------------------------

void ModuloScheduling::dumpScheduling(){
  modSched_os<<"dump schedule:"<<"\n";
  const MachineSchedInfo& msi=target.getSchedInfo();
  unsigned numIssueSlots=msi.maxNumIssueTotal;
  for(unsigned i=0;i< numIssueSlots;i++)
    modSched_os <<"\t#";
  modSched_os<<"\n";
  for(unsigned i=0;i < schedule.size();i++)
    {
      modSched_os<<"cycle"<<i<<": ";
      for(unsigned j=0;j<schedule[i].size();j++)
	if(schedule[i][j]!= NULL)
	  modSched_os<<schedule[i][j]->getNodeId()<<"\t";
	else
	  modSched_os<<"\t";
      modSched_os<<"\n";
    }
  
  modSched_os<<"dump coreSchedule:"<<"\n";
  for(unsigned i=0;i< numIssueSlots;i++)
    modSched_os <<"\t#";
  modSched_os<<"\n";
  for(unsigned i=0;i < coreSchedule.size();i++){
    modSched_os<<"cycle"<<i<<": ";
    for(unsigned j=0;j< coreSchedule[i].size();j++)
      if(coreSchedule[i][j] !=NULL)
	modSched_os<<coreSchedule[i][j]->getNodeId()<<"\t";
      else
	modSched_os<<"\t";
    modSched_os<<"\n";
  }
}



//---------------------------------------------------------------------------
// Function: ModuloSchedulingPass
// 
// Purpose:
//   Entry point for Modulo Scheduling
//   Schedules LLVM instruction
//   
//---------------------------------------------------------------------------

namespace {
  class ModuloSchedulingPass : public FunctionPass {
    const TargetMachine &target;
  public:
    ModuloSchedulingPass(const TargetMachine &T) : target(T) {}
    const char *getPassName() const { return "Modulo Scheduling"; }
    
    // getAnalysisUsage - We use LiveVarInfo...
    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
      //AU.addRequired(FunctionLiveVarInfo::ID);
    }
    bool runOnFunction(Function &F);
  };
} // end anonymous namespace



bool ModuloSchedulingPass::runOnFunction(Function &F)
{
 
  //if necessary , open the output for debug purpose
  if(ModuloSchedDebugLevel== ModuloSched_Disable)
    return false;
  
  if(ModuloSchedDebugLevel>= ModuloSched_PrintSchedule){
    modSched_fb.open("moduloSchedDebugInfo.output", ios::out);
    modSched_os<<"******************Modula Scheduling debug information*************************"<<endl;
  }
  
  ModuloSchedGraphSet* graphSet = new ModuloSchedGraphSet(&F,target);
  ModuloSchedulingSet ModuloSchedulingSet(*graphSet);
  
  if(ModuloSchedDebugLevel>= ModuloSched_PrintSchedule)
    modSched_fb.close();
  
  return false;
}


Pass *createModuloSchedulingPass(const TargetMachine &tgt) {
  return new ModuloSchedulingPass(tgt);
}