//===-- TransformFunctionBody.cpp - Pool Function Transformer -------------===//
// 
//                     The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
// 
//===----------------------------------------------------------------------===//
//
// This file defines the PoolAllocate::TransformBody method.
//
//===----------------------------------------------------------------------===//

#define DEBUG_TYPE "PoolAllocator"

#include "dsa/DataStructure.h"
#include "dsa/DSGraph.h"
#include "dsa/CallTargets.h"
#include "poolalloc/PoolAllocate.h"
#include "llvm/Module.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Constants.h"
#include "llvm/Instructions.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Support/InstVisitor.h"
#include "llvm/Support/Debug.h"
#include "llvm/ADT/VectorExtras.h"
#include <iostream>
using namespace llvm;
using namespace PA;

//
// Flag: UsingBugpoint
//
// Description:
//  There are certain assertions that interfere with bugpoint's ability to
//  reduce test cases.  When using bugpoint, set this variable to true.
//
static bool UsingBugpoint = false;

//
// Variables for referencing LLVM basic types.
//
static const Type * VoidType  = 0;
static const Type * Int8Type  = 0;
static const Type * Int32Type = 0;
static const Type * Int64Type = 0;

namespace {
  /// FuncTransform - This class implements transformation required of pool
  /// allocated functions.
  struct FuncTransform : public InstVisitor<FuncTransform> {
    PoolAllocate &PAInfo;
    DSGraph* G;      // The Bottom-up DS Graph
    FuncInfo &FI;

    // PoolUses - For each pool (identified by the pool descriptor) keep track
    // of which blocks require the memory in the pool to not be freed.  This
    // does not include poolfree's.  Note that this is only tracked for pools
    // which this is the home of, ie, they are Alloca instructions.
    std::multimap<AllocaInst*, Instruction*> &PoolUses;

    // PoolDestroys - For each pool, keep track of the actual poolfree calls
    // inserted into the code.  This is seperated out from PoolUses.
    std::multimap<AllocaInst*, CallInst*> &PoolFrees;

    FuncTransform(PoolAllocate &P, DSGraph* g, FuncInfo &fi,
                  std::multimap<AllocaInst*, Instruction*> &poolUses,
                  std::multimap<AllocaInst*, CallInst*> &poolFrees)
      : PAInfo(P), G(g), FI(fi), 
        PoolUses(poolUses), PoolFrees(poolFrees) {
      //
      // Get pointers to 8 and 32 bit LLVM integer types.
      //
      VoidType  = Type::getVoidTy(getGlobalContext());
      Int8Type  = IntegerType::getInt8Ty(getGlobalContext());
      Int32Type = IntegerType::getInt32Ty(getGlobalContext());
      Int64Type = IntegerType::getInt64Ty(getGlobalContext());
    }

    template <typename InstType, typename SetType>
    void AddPoolUse(InstType &I, Value *PoolHandle, SetType &Set) {
      if (AllocaInst *AI = dyn_cast<AllocaInst>(PoolHandle))
        Set.insert(std::make_pair(AI, &I));
    }

    void visitInstruction(Instruction &I);
    void visitMallocInst(MallocInst &MI);
    void visitAllocaInst(AllocaInst &MI);
    void visitCallocCall(CallSite CS);
    void visitReallocCall(CallSite CS);
    void visitMemAlignCall(CallSite CS);
    void visitStrdupCall(CallSite CS);
    void visitFreeInst(FreeInst &FI);
    void visitCallSite(CallSite &CS);
    void visitCallInst(CallInst &CI) {
      CallSite CS(&CI);
      visitCallSite(CS);
    }
    void visitInvokeInst(InvokeInst &II) {
      CallSite CS(&II);
      visitCallSite(CS);
    }
    void visitLoadInst(LoadInst &I);
    void visitStoreInst (StoreInst &I);

  private:
    Instruction *TransformAllocationInstr(Instruction *I, Value *Size);
    Instruction *InsertPoolFreeInstr(Value *V, Instruction *Where);

    void UpdateNewToOldValueMap(Value *OldVal, Value *NewV1, Value *NewV2 = 0) {
      std::map<Value*, const Value*>::iterator I =
        FI.NewToOldValueMap.find(OldVal);
      assert(I != FI.NewToOldValueMap.end() && "OldVal not found in clone?");
      FI.NewToOldValueMap.insert(std::make_pair(NewV1, I->second));
      if (NewV2)
        FI.NewToOldValueMap.insert(std::make_pair(NewV2, I->second));
      FI.NewToOldValueMap.erase(I);
    }

    Value* getOldValueIfAvailable(Value* V) {
      if (!FI.NewToOldValueMap.empty()) {
        // If the NewToOldValueMap is in effect, use it.
        std::map<Value*,const Value*>::iterator I = FI.NewToOldValueMap.find(V);
        if (I != FI.NewToOldValueMap.end())
          V = (Value*)I->second;
      }
      return V;
    }

    DSNodeHandle& getDSNodeHFor(Value *V) {
      return G->getScalarMap()[getOldValueIfAvailable(V)];
    }

    Value *getPoolHandle(Value *V) {
      DSNode *Node = getDSNodeHFor(V).getNode();
      // Get the pool handle for this DSNode...
      std::map<const DSNode*, Value*>::iterator I =
        FI.PoolDescriptors.find(Node);
      return I != FI.PoolDescriptors.end() ? I->second : 0;
    }
    
    Function* retCloneIfFunc(Value *V);
  };
}

void PoolAllocate::TransformBody(DSGraph* g, PA::FuncInfo &fi,
                              std::multimap<AllocaInst*,Instruction*> &poolUses,
                              std::multimap<AllocaInst*, CallInst*> &poolFrees,
                                 Function &F) {
  FuncTransform(*this, g, fi, poolUses, poolFrees).visit(F);
}


// Returns the clone if  V is a static function (not a pointer) and belongs 
// to an equivalence class i.e. is pool allocated
Function* FuncTransform::retCloneIfFunc(Value *V) {
  if (Function *F = dyn_cast<Function>(V))
    if (FuncInfo *FI = PAInfo.getFuncInfo(*F))
      return FI->Clone;

  return 0;
}

void FuncTransform::visitLoadInst(LoadInst &LI) {
  if (Value *PH = getPoolHandle(LI.getOperand(0)))
    AddPoolUse(LI, PH, PoolUses);
  visitInstruction(LI);
}

void FuncTransform::visitStoreInst(StoreInst &SI) {
  if (Value *PH = getPoolHandle(SI.getOperand(1)))
    AddPoolUse(SI, PH, PoolUses);
  visitInstruction(SI);
}

Instruction *FuncTransform::TransformAllocationInstr(Instruction *I,
                                                     Value *Size) {
  std::string Name = I->getName(); I->setName("");

  if (Size->getType() != Int32Type)
    Size = CastInst::CreateIntegerCast(Size, Int32Type, false, Size->getName(), I);

  // Insert a call to poolalloc
  Value *PH = getPoolHandle(I);

  // Do not change the instruction into a poolalloc() call unless we have a
  // real pool descriptor
  if (PH == 0 || isa<ConstantPointerNull>(PH)) return I;
  
  Value* Opts[2] = {PH, Size};
  Instruction *V = CallInst::Create(PAInfo.PoolAlloc, Opts, Opts + 2, Name, I);

  AddPoolUse(*V, PH, PoolUses);

  // Cast to the appropriate type if necessary
  Instruction *Casted = V;
  if (V->getType() != I->getType())
    Casted = CastInst::CreatePointerCast(V, I->getType(), V->getName(), I);
    
  // Update def-use info
  I->replaceAllUsesWith(Casted);

  // If we are modifying the original function, update the DSGraph.
  if (!FI.Clone) {
    // V and Casted now point to whatever the original allocation did.
    G->getScalarMap().replaceScalar(I, V);
    if (V != Casted)
      G->getScalarMap()[Casted] = G->getScalarMap()[V];
  } else {             // Otherwise, update the NewToOldValueMap
    UpdateNewToOldValueMap(I, V, V != Casted ? Casted : 0);
  }

  // If this was an invoke, fix up the CFG.
  if (InvokeInst *II = dyn_cast<InvokeInst>(I)) {
    BranchInst::Create (II->getNormalDest(), I);
    II->getUnwindDest()->removePredecessor(II->getParent(), true);
  }

  // Remove old allocation instruction.
  I->eraseFromParent();
  return Casted;
}


void FuncTransform::visitMallocInst(MallocInst &MI) {
  // Get the pool handle for the node that this contributes to...
  Value *PH = getPoolHandle(&MI);
  
  if (PH == 0 || isa<ConstantPointerNull>(PH)) return;

  TargetData &TD = PAInfo.getAnalysis<TargetData>();
  Value *AllocSize = ConstantInt::get(Int32Type,
				      TD.getTypeAllocSize(MI.getAllocatedType()));

  if (MI.isArrayAllocation())
    AllocSize = BinaryOperator::Create(Instruction::Mul, AllocSize,
                                       MI.getOperand(0), "sizetmp", &MI);
  //
  // NOTE:
  //  The code below used to be used by SAFECode.  However, it requires
  //  Pool Allocation to depend upon SAFECode passes, which is messy.
  //
  //  I believe the code below is an unneeded optimization.  Basically, when
  //  SAFECode promotes a stack allocation to the heap, this makes it a stack
  //  allocation again if the DSNode has no heap allocations.  This seems to be
  //  a performance optimization and unnecessary for the first prototype.
  //
  if (PAInfo.SAFECodeEnabled) {
#if 0
    const MallocInst *originalMalloc = &MI;
    if (FI.NewToOldValueMap.count(&MI)) {
      originalMalloc = cast<MallocInst>(FI.NewToOldValueMap[&MI]);
    }
    //Dinakar to test stack safety & array safety 
    if (PAInfo.CUAPass->ArrayMallocs.find(originalMalloc) ==
        PAInfo.CUAPass->ArrayMallocs.end()) {
      TransformAllocationInstr(&MI, AllocSize);
    } else {
      AllocaInst *AI = new AllocaInst(MI.getType()->getElementType(), MI.getArraySize(), MI.getName(), MI.getNext());
      MI.replaceAllUsesWith(AI);
      MI.getParent()->getInstList().erase(&MI);
      Value *Casted = AI;
      Instruction *aiNext = AI->getNext();
      if (AI->getType() != PointerType::getUnqual(Int8Type))
        Casted = CastInst::CreatePointerCast(AI, PointerType::getUnqual(Int8Type),
              AI->getName()+".casted",aiNext);
      
      Instruction *V = CallInst::Create(PAInfo.PoolRegister,
            make_vector(PH, AllocSize, Casted, 0), "", aiNext);
      AddPoolUse(*V, PH, PoolUses);
    }
#else
    TransformAllocationInstr(&MI, AllocSize);  
#endif
  } else {
    TransformAllocationInstr(&MI, AllocSize);  
  }
}

void FuncTransform::visitAllocaInst(AllocaInst &MI) {
  //
  // SAFECode will register alloca instructions with the run-time, so do not
  // do that here.
  //
  // FIXME:
  //  There is a chance that we may need to update PoolUses to make sure that
  //  the pool handle is available in this function.
  //
  return;
}


Instruction *FuncTransform::InsertPoolFreeInstr(Value *Arg, Instruction *Where){
  Value *PH = getPoolHandle(Arg);  // Get the pool handle for this DSNode...
  if (PH == 0 || isa<ConstantPointerNull>(PH)) return 0;

  // Insert a cast and a call to poolfree...
  Value *Casted = Arg;
  if (Arg->getType() != PointerType::getUnqual(Int8Type)) {
    Casted = CastInst::CreatePointerCast(Arg, PointerType::getUnqual(Int8Type),
				 Arg->getName()+".casted", Where);
    G->getScalarMap()[Casted] = G->getScalarMap()[Arg];
  }

  Value* Opts[2] = {PH, Casted};
  CallInst *FreeI = CallInst::Create(PAInfo.PoolFree, Opts, Opts + 2, "", Where);
  AddPoolUse(*FreeI, PH, PoolFrees);
  return FreeI;
}


void FuncTransform::visitFreeInst(FreeInst &FrI) {
  if (Instruction *I = InsertPoolFreeInstr(FrI.getOperand(0), &FrI)) {
    // Delete the now obsolete free instruction...
    FrI.getParent()->getInstList().erase(&FrI);
 
    // Update the NewToOldValueMap if this is a clone
    if (!FI.NewToOldValueMap.empty()) {
      std::map<Value*,const Value*>::iterator II =
        FI.NewToOldValueMap.find(&FrI);
      assert(II != FI.NewToOldValueMap.end() && 
             "FrI not found in clone?");
      FI.NewToOldValueMap.insert(std::make_pair(I, II->second));
      FI.NewToOldValueMap.erase(II);
    }
  }
}


void FuncTransform::visitCallocCall(CallSite CS) {
  TargetData& TD = PAInfo.getAnalysis<TargetData>();
  bool useLong = TD.getTypeAllocSize(PointerType::getUnqual(Int8Type)) != 4;
  
  Module *M = CS.getInstruction()->getParent()->getParent()->getParent();
  assert(CS.arg_end()-CS.arg_begin() == 2 && "calloc takes two arguments!");
  Value *V1 = CS.getArgument(0);
  Value *V2 = CS.getArgument(1);
  if (V1->getType() != V2->getType()) {
    V1 = CastInst::CreateZExtOrBitCast(V1, useLong ? Int64Type : Int32Type, V1->getName(), CS.getInstruction());
    V2 = CastInst::CreateZExtOrBitCast(V2, useLong ? Int64Type : Int32Type, V2->getName(), CS.getInstruction());
  }

  V2 = BinaryOperator::Create(Instruction::Mul, V1, V2, "size",
                              CS.getInstruction());
  if (V2->getType() != (useLong ? Int64Type : Int32Type))
    V2 = CastInst::CreateZExtOrBitCast(V2, useLong ? Int64Type : Int32Type, V2->getName(), CS.getInstruction());

  BasicBlock::iterator BBI =
    TransformAllocationInstr(CS.getInstruction(), V2);
  Value *Ptr = BBI++;

  // We just turned the call of 'calloc' into the equivalent of malloc.  To
  // finish calloc, we need to zero out the memory.
  Constant *MemSet =  M->getOrInsertFunction((useLong ? "llvm.memset.i64" : "llvm.memset.i32"),
                                             VoidType,
                                             PointerType::getUnqual(Int8Type),
                                             Int8Type, (useLong ? Int64Type : Int32Type),
                                             Int32Type, NULL);

  if (Ptr->getType() != PointerType::getUnqual(Int8Type))
    Ptr = CastInst::CreatePointerCast(Ptr, PointerType::getUnqual(Int8Type), Ptr->getName(),
                       BBI);
  
  // We know that the memory returned by poolalloc is at least 4 byte aligned.
  Value* Opts[4] = {Ptr, ConstantInt::get(Int8Type, 0),
                    V2,  ConstantInt::get(Int32Type, 4)};
  CallInst::Create(MemSet, Opts, Opts + 4, "", BBI);
}


void FuncTransform::visitReallocCall(CallSite CS) {
  assert(CS.arg_end()-CS.arg_begin() == 2 && "realloc takes two arguments!");
  Instruction *I = CS.getInstruction();
  Value *PH = getPoolHandle(I);
  Value *OldPtr = CS.getArgument(0);
  Value *Size = CS.getArgument(1);

  // Don't poolallocate if we have no pool handle
  if (PH == 0 || isa<ConstantPointerNull>(PH)) return;

  if (Size->getType() != Int32Type)
    Size = CastInst::CreateIntegerCast(Size, Int32Type, false, Size->getName(), I);

  static Type *VoidPtrTy = PointerType::getUnqual(Int8Type);
  if (OldPtr->getType() != VoidPtrTy)
    OldPtr = CastInst::CreatePointerCast(OldPtr, VoidPtrTy, OldPtr->getName(), I);

  std::string Name = I->getName(); I->setName("");
  Value* Opts[3] = {PH, OldPtr, Size};
  Instruction *V = CallInst::Create(PAInfo.PoolRealloc, Opts, Opts + 3, Name, I);
  Instruction *Casted = V;
  if (V->getType() != I->getType())
    Casted = CastInst::CreatePointerCast(V, I->getType(), V->getName(), I);

  // Update def-use info
  I->replaceAllUsesWith(Casted);

  // If we are modifying the original function, update the DSGraph.
  if (!FI.Clone) {
    // V and Casted now point to whatever the original allocation did.
    G->getScalarMap().replaceScalar(I, V);
    if (V != Casted)
      G->getScalarMap()[Casted] = G->getScalarMap()[V];
  } else {             // Otherwise, update the NewToOldValueMap
    UpdateNewToOldValueMap(I, V, V != Casted ? Casted : 0);
  }

  // If this was an invoke, fix up the CFG.
  if (InvokeInst *II = dyn_cast<InvokeInst>(I)) {
    BranchInst::Create (II->getNormalDest(), I);
    II->getUnwindDest()->removePredecessor(II->getParent(), true);
  }

  // Remove old allocation instruction.
  I->eraseFromParent();
}


/// visitMemAlignCall - Handle memalign and posix_memalign.
///
void FuncTransform::visitMemAlignCall(CallSite CS) {
  Instruction *I = CS.getInstruction();
  Value *ResultDest = 0;
  Value *Align = 0;
  Value *Size = 0;
  Value *PH;

  if (CS.getCalledFunction()->getName() == "memalign") {
    Align = CS.getArgument(0);
    Size = CS.getArgument(1);
    PH = getPoolHandle(I);
  } else {
    assert(CS.getCalledFunction()->getName() == "posix_memalign");
    ResultDest = CS.getArgument(0);
    Align   = CS.getArgument(1);
    Size    = CS.getArgument(2);

    assert(0 && "posix_memalign not implemented fully!");
    // We need to get the pool descriptor corresponding to *ResultDest.
    PH = getPoolHandle(I);

    // Return success always.
    const PointerType * PT = dyn_cast<PointerType>(I->getType());
    assert (PT && "memalign() does not return pointer type!\n");
    Value *RetVal = ConstantPointerNull::get(PT);
    I->replaceAllUsesWith(RetVal);

    static const Type *PtrPtr=PointerType::getUnqual(PointerType::getUnqual(Int8Type));
    if (ResultDest->getType() != PtrPtr)
      ResultDest = CastInst::CreatePointerCast(ResultDest, PtrPtr, ResultDest->getName(), I);
  }

  if (Align->getType() != Int32Type)
    Align = CastInst::CreateIntegerCast(Align, Int32Type, false, Align->getName(), I);
  if (Size->getType() != Int32Type)
    Size = CastInst::CreateIntegerCast(Size, Int32Type, false, Size->getName(), I);

  std::string Name = I->getName(); I->setName("");
  Value* Opts[3] = {PH, Align, Size};
  Instruction *V = CallInst::Create(PAInfo.PoolMemAlign, Opts, Opts + 3, Name, I);

  Instruction *Casted = V;
  if (V->getType() != I->getType())
    Casted = CastInst::CreatePointerCast(V, I->getType(), V->getName(), I);

  if (ResultDest)
    new StoreInst(V, ResultDest, I);
  else
    I->replaceAllUsesWith(Casted);

  // If we are modifying the original function, update the DSGraph.
  if (!FI.Clone) {
    // V and Casted now point to whatever the original allocation did.
    G->getScalarMap().replaceScalar(I, V);
    if (V != Casted)
      G->getScalarMap()[Casted] = G->getScalarMap()[V];
  } else {             // Otherwise, update the NewToOldValueMap
    UpdateNewToOldValueMap(I, V, V != Casted ? Casted : 0);
  }

  // If this was an invoke, fix up the CFG.
  if (InvokeInst *II = dyn_cast<InvokeInst>(I)) {
    BranchInst::Create (II->getNormalDest(), I);
    II->getUnwindDest()->removePredecessor(II->getParent(), true);
  }

  // Remove old allocation instruction.
  I->eraseFromParent();
}

/// visitStrdupCall - Handle strdup().
///
void FuncTransform::visitStrdupCall(CallSite CS) {
  assert(CS.arg_end()-CS.arg_begin() == 1 && "strdup takes one argument!");
  Instruction *I = CS.getInstruction();
  DSNode *Node = getDSNodeHFor(I).getNode();
  assert (Node && "strdup has NULL DSNode!\n");
  Value *PH = getPoolHandle(I);
#if 0
  assert (PH && "PH for strdup is null!\n");
#else
  if (!PH) {
    std::cerr << "strdup: NoPH" << std::endl;
    return;
  }
#endif
  Value *OldPtr = CS.getArgument(0);

  static Type *VoidPtrTy = PointerType::getUnqual(Int8Type);
  if (OldPtr->getType() != VoidPtrTy)
    OldPtr = CastInst::CreatePointerCast(OldPtr, VoidPtrTy, OldPtr->getName(), I);

  std::string Name = I->getName(); I->setName("");
  Value* Opts[3] = {PH, OldPtr, 0};
  Instruction *V = CallInst::Create(PAInfo.PoolStrdup, Opts, Opts + 2, Name, I);
  Instruction *Casted = V;
  if (V->getType() != I->getType())
    Casted = CastInst::CreatePointerCast(V, I->getType(), V->getName(), I);

  // Update def-use info
  I->replaceAllUsesWith(Casted);

  // If we are modifying the original function, update the DSGraph.
  if (!FI.Clone) {
    // V and Casted now point to whatever the original allocation did.
    G->getScalarMap().replaceScalar(I, V);
    if (V != Casted)
      G->getScalarMap()[Casted] = G->getScalarMap()[V];
  } else {             // Otherwise, update the NewToOldValueMap
    UpdateNewToOldValueMap(I, V, V != Casted ? Casted : 0);
  }

  // If this was an invoke, fix up the CFG.
  if (InvokeInst *II = dyn_cast<InvokeInst>(I)) {
    BranchInst::Create (II->getNormalDest(), I);
    II->getUnwindDest()->removePredecessor(II->getParent(), true);
  }

  // Remove old allocation instruction.
  I->eraseFromParent();
}


void FuncTransform::visitCallSite(CallSite& CS) {
  const Function *CF = CS.getCalledFunction();
  Instruction *TheCall = CS.getInstruction();
  bool thread_creation_point = false;

  // If the called function is casted from one function type to another, peer
  // into the cast instruction and pull out the actual function being called.
  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(CS.getCalledValue()))
    if (CE->getOpcode() == Instruction::BitCast &&
        isa<Function>(CE->getOperand(0)))
      CF = cast<Function>(CE->getOperand(0));

  if (isa<InlineAsm>(TheCall->getOperand(0))) {
    std::cerr << "INLINE ASM: ignoring.  Hoping that's safe.\n";
    return;
  }

  // Ignore calls to NULL pointers.
  if (isa<ConstantPointerNull>(CS.getCalledValue())) {
    std::cerr << "WARNING: Ignoring call using NULL function pointer.\n";
    return;
  }

  // If this function is one of the memory manipulating functions built into
  // libc, emulate it with pool calls as appropriate.
  if (CF && CF->isDeclaration()) {
    if (CF->getName() == "calloc") {
      visitCallocCall(CS);
      return;
    } else if (CF->getName() == "realloc") {
      visitReallocCall(CS);
      return;
    } else if (CF->getName() == "memalign" ||
               CF->getName() == "posix_memalign") {
      visitMemAlignCall(CS);
      return;
    } else if (CF->getName() == "strdup") {
      visitStrdupCall(CS);
      return;
    } else if (CF->getName() == "valloc") {
      std::cerr << "VALLOC USED BUT NOT HANDLED!\n";
      abort();
    } else if (CF->getName() == "pthread_create") {
      thread_creation_point = true;

      //Get DSNode representing the DSNode of the function pointer Value of the pthread_create call
      DSNode* thread_callee_node = G->getNodeForValue(CS.getArgument(2)).getNode();
      if(!thread_callee_node)
      {
    	  assert(0 && "apparently you need this code");
    	  FuncInfo *CFI = PAInfo.getFuncInfo(*CF);
    	  thread_callee_node = G->getNodeForValue(CFI->MapValueToOriginal(CS.getArgument(2))).getNode();
      }

      //Fill in CF with the name of one of the functions in thread_callee_node
      CF = const_cast<Function*>(dyn_cast<Function>(*thread_callee_node->globals_begin()));
    }
  }

  // We need to figure out which local pool descriptors correspond to the pool
  // descriptor arguments passed into the function call.  Calculate a mapping
  // from callee DSNodes to caller DSNodes.  We construct a partial isomophism
  // between the graphs to figure out which pool descriptors need to be passed
  // in.  The roots of this mapping is found from arguments and return values.
  //
  DataStructures& Graphs = PAInfo.getGraphs();
  DSGraph::NodeMapTy NodeMapping;
  Instruction *NewCall;
  Value *NewCallee;
  std::vector<const DSNode*> ArgNodes;
  DSGraph *CalleeGraph;  // The callee graph

  // For indirect callees, find any callee since all DS graphs have been
  // merged.
  if (CF) {   // Direct calls are nice and simple.
    DEBUG(std::cerr << "  Handling direct call: " << *TheCall);
    FuncInfo *CFI = PAInfo.getFuncInfo(*CF);
    if (CFI == 0 || CFI->Clone == 0) {   // Nothing to transform...
      visitInstruction(*TheCall);
      return;
    }
    NewCallee = CFI->Clone;
    ArgNodes = CFI->ArgNodes;
    
    assert ((Graphs.hasDSGraph (*CF)) && "Function has no ECGraph!\n");
    CalleeGraph = Graphs.getDSGraph(*CF);
  } else {
    DEBUG(std::cerr << "  Handling indirect call: " << *TheCall);
    
    // Here we fill in CF with one of the possible called functions.  Because we
    // merged together all of the arguments to all of the functions in the
    // equivalence set, it doesn't really matter which one we pick.
    // (If the function was cloned, we have to map the cloned call instruction
    // in CS back to the original call instruction.)
    Instruction *OrigInst =
      cast<Instruction>(getOldValueIfAvailable(CS.getInstruction()));

    DataStructures::callee_iterator I = Graphs.callee_begin(OrigInst);
    if (I != Graphs.callee_end(OrigInst))
      CF = *I;
    
    // If we didn't find the callee in the constructed call graph, try
    // checking in the DSNode itself.
    // This isn't ideal as it means that this call site didn't have inlining
    // happen.
    if (!CF) {
      DSGraph* dg = Graphs.getDSGraph(*OrigInst->getParent()->getParent());
      DSNode* d = dg->getNodeForValue(OrigInst->getOperand(0)).getNode();
      assert (d && "No DSNode!\n");
      std::vector<const Function*> g;
      d->addFullFunctionList(g);
      if (g.size()) {
        EquivalenceClasses< const GlobalValue *> & EC = dg->getGlobalECs();
        for(std::vector<const Function*>::const_iterator ii = g.begin(), ee = g.end();
            !CF && ii != ee; ++ii) {
          for (EquivalenceClasses<const GlobalValue *>::member_iterator MI = EC.findLeader(*ii);
               MI != EC.member_end(); ++MI)   // Loop over members in this set.
            if ((CF = dyn_cast<Function>(*MI))) {
              break;
            }
        }
      }
    }

    //
    // Do an assert unless we're bugpointing something.
    //
    if ((UsingBugpoint) && (!CF)) return;
    assert (CF && "No call graph info");

    // Get the common graph for the set of functions this call may invoke.
    if (UsingBugpoint && (!(Graphs.hasDSGraph(*CF)))) return;
    assert ((Graphs.hasDSGraph(*CF)) && "Function has no DSGraph!\n");
    CalleeGraph = Graphs.getDSGraph(*CF);
    
#ifndef NDEBUG
    // Verify that all potential callees at call site have the same DS graph.
    DataStructures::callee_iterator E = Graphs.callee_end(OrigInst);
    for (; I != E; ++I)
      if (!(*I)->isDeclaration())
        assert(CalleeGraph == Graphs.getDSGraph(**I) &&
               "Callees at call site do not have a common graph!");
#endif    

    // Find the DS nodes for the arguments that need to be added, if any.
    FuncInfo *CFI = PAInfo.getFuncInfo(*CF);
    assert(CFI && "No function info for callee at indirect call?");
    ArgNodes = CFI->ArgNodes;

    if (ArgNodes.empty())
      return;           // No arguments to add?  Transformation is a noop!

    // Cast the function pointer to an appropriate type!
    std::vector<const Type*> ArgTys(ArgNodes.size(),
                                    PoolAllocate::PoolDescPtrTy);
    for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
         I != E; ++I)
      ArgTys.push_back((*I)->getType());
    
    FunctionType *FTy = FunctionType::get(TheCall->getType(), ArgTys, false);
    PointerType *PFTy = PointerType::getUnqual(FTy);
    
    // If there are any pool arguments cast the func ptr to the right type.
    NewCallee = CastInst::CreatePointerCast(CS.getCalledValue(), PFTy, "tmp", TheCall);
  }

  Function::const_arg_iterator FAI = CF->arg_begin(), E = CF->arg_end();
  CallSite::arg_iterator AI = CS.arg_begin() + (thread_creation_point ? 3 : 0), AE = CS.arg_end();
  for ( ; FAI != E && AI != AE; ++FAI, ++AI)
    if (!isa<Constant>(*AI))
      DSGraph::computeNodeMapping(CalleeGraph->getNodeForValue(FAI),
                                  getDSNodeHFor(*AI), NodeMapping, false);

  //assert(AI == AE && "Varargs calls not handled yet!");

  // Map the return value as well...
  if (isa<PointerType>(TheCall->getType()))
    DSGraph::computeNodeMapping(CalleeGraph->getReturnNodeFor(*CF),
                                getDSNodeHFor(TheCall), NodeMapping, false);

  // This code seems redundant (and crashes occasionally)
  // There is no reason to map globals here, since they are not passed as
  // arguments

//   // Map the nodes that are pointed to by globals.
//    DSScalarMap &CalleeSM = CalleeGraph->getScalarMap();
//    for (DSScalarMap::global_iterator GI = G.getScalarMap().global_begin(), 
//           E = G.getScalarMap().global_end(); GI != E; ++GI)
//      if (CalleeSM.count(*GI))
//        DSGraph::computeNodeMapping(CalleeGraph->getNodeForValue(*GI),
//                                    getDSNodeHFor(*GI),
//                                    NodeMapping, false);

  // Okay, now that we have established our mapping, we can figure out which
  // pool descriptors to pass in...
  std::vector<Value*> Args;
  for (unsigned i = 0, e = ArgNodes.size(); i != e; ++i) {
    Value *ArgVal = Constant::getNullValue(PoolAllocate::PoolDescPtrTy);
    if (NodeMapping.count(ArgNodes[i]))
      if (DSNode *LocalNode = NodeMapping[ArgNodes[i]].getNode())
        if (FI.PoolDescriptors.count(LocalNode))
          ArgVal = FI.PoolDescriptors.find(LocalNode)->second;
    if (isa<Constant>(ArgVal) && cast<Constant>(ArgVal)->isNullValue()) {
      if ((!(PAInfo.BoundsChecksEnabled)) || (ArgNodes[i]->isArray())) {
        if (!isa<InvokeInst>(TheCall)) {
          // Dinakar: We need pooldescriptors for allocas in the callee if it
          //          escapes
          BasicBlock::iterator InsertPt = TheCall->getParent()->getParent()->front().begin();
          ArgVal =  new AllocaInst(PAInfo.getPoolType(),
                                   0,
                                   "PD",
                                   InsertPt);
          Value *ElSize = ConstantInt::get(Int32Type,0);
          Value *Align  = ConstantInt::get(Int32Type,0);
          Value* Opts[3] = {ArgVal, ElSize, Align};
          CallInst::Create(PAInfo.PoolInit, Opts, Opts + 3,"", TheCall);
          BasicBlock::iterator BBI = TheCall;
          CallInst::Create(PAInfo.PoolDestroy, ArgVal, "", ++BBI);
        }

        //probably need to update DSG
        //      std::cerr << "WARNING: NULL POOL ARGUMENTS ARE PASSED IN!\n";
      }
    }
    Args.push_back(ArgVal);
  }

  // Add the rest of the arguments unless we're a thread creation point, in which case we only need the pools
  if(!thread_creation_point)
	  Args.insert(Args.end(), CS.arg_begin(), CS.arg_end());
    
  //
  // There are circumstances where a function is casted to another type and
  // then called (que horible).  We need to perform a similar cast if the
  // type doesn't match the number of arguments.
  //
  if (Function * NewFunction = dyn_cast<Function>(NewCallee)) {
    const FunctionType * NewCalleeType = NewFunction->getFunctionType();
    if (NewCalleeType->getNumParams() != Args.size()) {
      std::vector<const Type *> Types;
      Type * FuncTy = FunctionType::get (NewCalleeType->getReturnType(),
                                         Types,
                                         true);
      FuncTy = PointerType::getUnqual (FuncTy);
      NewCallee = new BitCastInst (NewCallee, FuncTy, "", TheCall);
    }
  }

  std::string Name = TheCall->getName();    TheCall->setName("");

  if(thread_creation_point) {
	Module *M = CS.getInstruction()->getParent()->getParent()->getParent();
	Value* pthread_replacement = M->getFunction("poolalloc_pthread_create");
	vector<Value*> thread_args;

	//Push back original thread arguments through the callee
	thread_args.push_back(CS.getArgument(0));
	thread_args.push_back(CS.getArgument(1));
	thread_args.push_back(CS.getArgument(2));

	//Push back the integer argument saying how many uses there are
	thread_args.push_back(Constant::getIntegerValue(llvm::Type::getInt32Ty(M->getContext()),APInt(32,Args.size())));
	thread_args.insert(thread_args.end(),Args.begin(),Args.end());
	thread_args.push_back(CS.getArgument(3));

	//Make the thread creation call
	NewCall = CallInst::Create(pthread_replacement,
							   thread_args.begin(),thread_args.end(),
							   Name,TheCall);
  }
  else if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
    NewCall = InvokeInst::Create (NewCallee, II->getNormalDest(),
                                  II->getUnwindDest(),
                                  Args.begin(), Args.end(), Name, TheCall);
  } else {
    NewCall = CallInst::Create (NewCallee, Args.begin(), Args.end(), Name,
                                TheCall);
  }

  // Add all of the uses of the pool descriptor
  for (unsigned i = 0, e = ArgNodes.size(); i != e; ++i)
    AddPoolUse(*NewCall, Args[i], PoolUses);

  TheCall->replaceAllUsesWith(NewCall);
  DEBUG(std::cerr << "  Result Call: " << *NewCall);

  if (TheCall->getType() != VoidType) {
    // If we are modifying the original function, update the DSGraph... 
    DSGraph::ScalarMapTy &SM = G->getScalarMap();
    DSGraph::ScalarMapTy::iterator CII = SM.find(TheCall);
    if (CII != SM.end()) {
      SM[NewCall] = CII->second;
      SM.erase(CII);                     // Destroy the CallInst
    } else if (!FI.NewToOldValueMap.empty()) {
      // Otherwise, if this is a clone, update the NewToOldValueMap with the new
      // CI return value.
      UpdateNewToOldValueMap(TheCall, NewCall);
    }
  } else if (!FI.NewToOldValueMap.empty()) {
    UpdateNewToOldValueMap(TheCall, NewCall);
  }

  CallSite(NewCall).setCallingConv(CallSite(TheCall).getCallingConv());

  TheCall->eraseFromParent();
  visitInstruction(*NewCall);
}


// visitInstruction - For all instructions in the transformed function bodies,
// replace any references to the original calls with references to the
// transformed calls.  Many instructions can "take the address of" a function,
// and we must make sure to catch each of these uses, and transform it into a
// reference to the new, transformed, function.
void FuncTransform::visitInstruction(Instruction &I) {
  for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
    if (Function *clonedFunc = retCloneIfFunc(I.getOperand(i))) {
      Constant *CF = clonedFunc;
      I.setOperand(i, ConstantExpr::getPointerCast(CF, I.getOperand(i)->getType()));
    }
}