/* ###
 * IP: GHIDRA
 *
 * 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 "subflow.hh"

/// \brief Return \e slot of constant if INT_OR op sets all bits in mask, otherwise -1
///
/// \param orop is the given CPUI_INT_OR op
/// \param mask is the given mask
/// \return constant slot or -1
int4 SubvariableFlow::doesOrSet(PcodeOp *orop,uintb mask)

{
  int4 index = (orop->getIn(1)->isConstant() ? 1 : 0);
  if (!orop->getIn(index)->isConstant())
    return -1;
  uintb orval = orop->getIn(index)->getOffset();
  if ((mask&(~orval))==(uintb)0) // Are all masked bits one
    return index;
  return -1;
}

/// \brief Return \e slot of constant if INT_AND op clears all bits in mask, otherwise -1
///
/// \param andop is the given CPUI_INT_AND op
/// \param mask is the given mask
/// \return constant slot or -1
int4 SubvariableFlow::doesAndClear(PcodeOp *andop,uintb mask)

{
  int4 index = (andop->getIn(1)->isConstant() ? 1 : 0);
  if (!andop->getIn(index)->isConstant())
    return -1;
  uintb andval = andop->getIn(index)->getOffset();
  if ((mask&andval)==(uintb)0) // Are all masked bits zero
    return index;
  return -1;
}

/// \brief Add the given Varnode as a new node in the logical subgraph
///
/// A new ReplaceVarnode object is created, representing the given Varnode within
/// the logical subgraph, and returned.  If an object representing the Varnode already
/// exists it is returned.  A mask describing the subset of bits within the Varnode
/// representing the logical value is also passed in. This method also determines if
/// the new node needs to be added to the worklist for continued tracing.
/// \param vn is the given Varnode holding the logical value
/// \param mask is the given mask describing the bits of the logical value
/// \param inworklist will hold \b true if the new node should be traced further
/// \return the new subgraph variable node
SubvariableFlow::ReplaceVarnode *SubvariableFlow::setReplacement(Varnode *vn,uintb mask,bool &inworklist)

{
  ReplaceVarnode *res;
  if (vn->isMark()) {		// Already seen before
    map<Varnode *,ReplaceVarnode>::iterator iter;
    iter = varmap.find(vn);
    res = &(*iter).second;
    inworklist = false;
    if (res->mask != mask)
      return (ReplaceVarnode *)0;
    return res;
  }

  if (vn->isConstant()) {
    inworklist = false;
    if (sextrestrictions) {	// Check that -vn- is a sign extension
      uintb cval = vn->getOffset();
      uintb smallval = cval & mask; // From its logical size
      uintb sextval = sign_extend(smallval,flowsize,vn->getSize());// to its fullsize
      if (sextval != cval)
	return (ReplaceVarnode *)0;
    }
    return addConstant((ReplaceOp *)0,mask,0,vn);
  }

  if (vn->isFree())
    return (ReplaceVarnode *)0; // Abort

  if (vn->isAddrForce() && (vn->getSize() != flowsize))
    return (ReplaceVarnode *)0;

  if (sextrestrictions) {
    if (vn->getSize() != flowsize) {
      if ((!aggressive)&& vn->isInput()) return (ReplaceVarnode *)0; // Cannot assume input is sign extended
      if (vn->isPersist()) return (ReplaceVarnode *)0;
    }
    if (vn->isTypeLock()) {
      if (vn->getType()->getSize() != flowsize)
	return (ReplaceVarnode *)0;
    }
  }
  else {
    if (bitsize >= 8) {		// Not a flag
      // If the logical variable is not a flag, don't consider the case where multiple variables
      // are packed into a single location, i.e. always consider it a single variable
      if ((!aggressive)&&((vn->getConsume()&~mask)!=0)) // If there is any use of value outside of the logical variable
	return (ReplaceVarnode *)0; // This probably means the whole thing is a variable, i.e. quit
      if (vn->isTypeLock()) {
	int4 sz = vn->getType()->getSize();
	if (sz != flowsize)
	  return (ReplaceVarnode *)0;
      }
    }
    
    if (vn->isInput()) {		// Must be careful with inputs
      // Inputs must come in from the right register/memory
      if (bitsize < 8) return (ReplaceVarnode *)0; // Dont create input flag
      if ((mask&1)==0) return (ReplaceVarnode *)0; // Dont create unique input
      // Its extremely important that the code (above) which doesn't allow packed variables be applied
      // or the mechanisms we use for inputs will give us spurious temporary inputs
    }
  }

  res = & varmap[ vn ];
  vn->setMark();
  res->vn = vn;
  res->replacement = (Varnode *)0;
  res->mask = mask;
  res->def = (ReplaceOp *)0;
  inworklist = true;
  // Check if vn already represents the logical variable being traced
  if (vn->getSize() == flowsize) {
    if (mask == calc_mask(flowsize)) {
      inworklist = false;
      res->replacement = vn;
    }
    else if (mask == 1) {
      if ((vn->isWritten())&&(vn->getDef()->isBoolOutput())) {
	inworklist = false;
	res->replacement = vn;
      }
    }
  }
  return res;
}

/// \brief Create a logical subgraph operator node given its output variable node
///
/// \param opc is the opcode of the new logical operator
/// \param numparam is the number of parameters in the new operator
/// \param outrvn is the given output variable node
/// \return the new logical subgraph operator object
SubvariableFlow::ReplaceOp *SubvariableFlow::createOp(OpCode opc,int4 numparam,ReplaceVarnode *outrvn)

{
  if (outrvn->def != (ReplaceOp *)0)
    return outrvn->def;
  oplist.emplace_back();
  ReplaceOp *rop = &oplist.back();
  outrvn->def = rop;
  rop->op = outrvn->vn->getDef();
  rop->numparams = numparam;
  rop->opc = opc;
  rop->output = outrvn;

  return rop;
}


/// \brief Create a logical subgraph operator node given one of its input variable nodes
///
/// \param opc is the opcode of the new logical operator
/// \param numparam is the number of parameters in the new operator
/// \param op is the original PcodeOp being replaced
/// \param inrvn is the given input variable node
/// \param slot is the input slot of the variable node
/// \return the new logical subgraph operator objects
SubvariableFlow::ReplaceOp *SubvariableFlow::createOpDown(OpCode opc,int4 numparam,PcodeOp *op,ReplaceVarnode *inrvn,int4 slot)

{
  oplist.emplace_back();
  ReplaceOp *rop = &oplist.back();
  rop->op = op;
  rop->opc = opc;
  rop->numparams = numparam;
  rop->output = (ReplaceVarnode *)0;
  while(rop->input.size() <= slot)
    rop->input.push_back((ReplaceVarnode *)0);
  rop->input[slot] = inrvn;
  return rop;
}

/// \brief Determine if the given subgraph variable can act as a parameter to the given CALL op
///
/// We assume the variable flows as a parameter to the CALL. If the CALL doesn't lock the parameter
/// size, create a PatchRecord within the subgraph that allows the CALL to take the parameter
/// with its smaller logical size.
/// \param op is the given CALL op
/// \param rvn is the given subgraph variable acting as a parameter
/// \param slot is the input slot of the variable within the CALL
/// \return \b true if the parameter can be successfully trimmed to its logical size
bool SubvariableFlow::tryCallPull(PcodeOp *op,ReplaceVarnode *rvn,int4 slot)

{
  if (slot == 0) return false;
  if (!aggressive) {
    if ((rvn->vn->getConsume()&~rvn->mask)!=0)	// If there's something outside the mask being consumed
      return false;				// Don't truncate
  }
  FuncCallSpecs *fc = fd->getCallSpecs(op);
  if (fc == (FuncCallSpecs *)0) return false;
  if (fc->isInputActive()) return false; // Don't trim while in the middle of figuring out params
  if (fc->isInputLocked() && (!fc->isDotdotdot())) return false;

  patchlist.emplace_back();
  patchlist.back().type = PatchRecord::parameter_patch;
  patchlist.back().patchOp = op;
  patchlist.back().in1 = rvn;
  patchlist.back().slot = slot;
  pullcount += 1;		// A true terminal modification
  return true;
}

/// \brief Determine if the given subgraph variable can act as return value for the given RETURN op
///
/// We assume the variable flows the RETURN. If the return value size is not locked. Create a
/// PatchRecord within the subgraph that allows the RETURN to take a smaller logical value.
/// \param op is the given RETURN op
/// \param rvn is the given subgraph variable flowing to the RETURN
/// \param slot is the input slot of the subgraph variable
/// \return \b true if the return value can be successfully trimmed to its logical size
bool SubvariableFlow::tryReturnPull(PcodeOp *op,ReplaceVarnode *rvn,int4 slot)

{
  if (slot == 0) return false;	// Don't deal with actual return address container
  if (fd->getFuncProto().isOutputLocked()) return false;
  if (!aggressive) {
    if ((rvn->vn->getConsume()&~rvn->mask)!=0)	// If there's something outside the mask being consumed
      return false;				// Don't truncate
  }

  if (!returnsTraversed) {
    // If we plan to truncate the size of a return variable, we need to propagate the logical size to any other
    // return variables so that there can still be a single return value type for the function
    list<PcodeOp *>::const_iterator iter,enditer;
    iter = fd->beginOp(CPUI_RETURN);
    enditer = fd->endOp(CPUI_RETURN);
    while(iter != enditer) {
      PcodeOp *retop = *iter;
      ++iter;
      if (retop->getHaltType() != 0) continue;		// Artificial halt
      Varnode *retvn = retop->getIn(slot);
      bool inworklist;
      ReplaceVarnode *rep = setReplacement(retvn,rvn->mask,inworklist);
      if (rep == (ReplaceVarnode *)0)
	return false;
      if (inworklist)
	worklist.push_back(rep);
      else if (retvn->isConstant() && retop != op) {
	// Trace won't revisit this RETURN, so we need to generate patch now
	patchlist.emplace_back();
	patchlist.back().type = PatchRecord::parameter_patch;
	patchlist.back().patchOp = retop;
	patchlist.back().in1 = rep;
	patchlist.back().slot = slot;
	pullcount += 1;
      }
    }
    returnsTraversed = true;
  }
  patchlist.emplace_back();
  patchlist.back().type = PatchRecord::parameter_patch;
  patchlist.back().patchOp = op;
  patchlist.back().in1 = rvn;
  patchlist.back().slot = slot;
  pullcount += 1;		// A true terminal modification
  return true;
}

/// \brief Determine if the given subgraph variable can act as a \e created value for the given INDIRECT op
///
/// Check if the INDIRECT is an \e indirect \e creation and is not representing a locked return value.
/// If we can, create the INDIRECT node in the subgraph representing the logical \e indirect \e creation.
/// \param op is the given INDIRECT
/// \param rvn is the given subgraph variable acting as the output of the INDIRECT
/// \return \b true if we can successfully trim the value to its logical size
bool SubvariableFlow::tryCallReturnPush(PcodeOp *op,ReplaceVarnode *rvn)

{
  if (!aggressive) {
    if ((rvn->vn->getConsume()&~rvn->mask)!=0)	// If there's something outside the mask being consumed
      return false;				// Don't truncate
  }
  if ((rvn->mask & 1) == 0) return false;	// Verify the logical value is the least significant part
  if (bitsize < 8) return false;		// Make sure logical value is at least a byte
  FuncCallSpecs *fc = fd->getCallSpecs(op);
  if (fc == (FuncCallSpecs *)0) return false;
  if (fc->isOutputLocked()) return false;
  if (fc->isOutputActive()) return false;	// Don't trim while in the middle of figuring out return value

  addPush(op,rvn);
  // pullcount += 1;		// This is a push NOT a pull
  return true;
}

/// \brief Determine if the subgraph variable can act as a switch variable for the given BRANCHIND
///
/// We query the JumpTable associated with the BRANCHIND to see if its switch variable
/// can be trimmed as indicated by the logical flow.
/// \param op is the given BRANCHIND op
/// \param rvn is the subgraph variable flowing to the BRANCHIND
/// \return \b true if the switch variable can be successfully trimmed to its logical size
bool SubvariableFlow::trySwitchPull(PcodeOp *op,ReplaceVarnode *rvn)

{
  if ((rvn->mask & 1) == 0) return false;	// Logical value must be justified
  if ((rvn->vn->getConsume()&~rvn->mask)!=0)	// If there's something outside the mask being consumed
    return false;				//  we can't trim
  patchlist.emplace_back();
  patchlist.back().type = PatchRecord::parameter_patch;
  patchlist.back().patchOp = op;
  patchlist.back().in1 = rvn;
  patchlist.back().slot = 0;
  pullcount += 1;		// A true terminal modification
  return true;
}

/// Try to trace the logical variable through descendant Varnodes
/// creating new nodes in the logical subgraph and updating the worklist.
/// \param rvn is the given subgraph variable to trace
/// \return \b true if the logical value can be traced forward one level
bool SubvariableFlow::traceForward(ReplaceVarnode *rvn)

{
  ReplaceOp *rop;
  PcodeOp *op;
  Varnode *outvn;
  int4 slot;
  int4 sa;
  uintb newmask;
  bool booldir;
  int4 dcount = 0;
  int4 hcount = 0;
  int4 callcount = 0;

  list<PcodeOp *>::const_iterator iter,enditer;
  enditer = rvn->vn->endDescend();
  for(iter = rvn->vn->beginDescend();iter != enditer;++iter) {
    op = *iter;
    outvn = op->getOut();
    if ((outvn!=(Varnode *)0)&&outvn->isMark()&&!op->isCall())
      continue;
    dcount += 1;		// Count this descendant
    slot = op->getSlot(rvn->vn);
    switch(op->code()) {
    case CPUI_COPY:
    case CPUI_MULTIEQUAL:
    case CPUI_INT_NEGATE:
    case CPUI_INT_XOR:
      rop = createOpDown(op->code(),op->numInput(),op,rvn,slot);
      if (!createLink(rop,rvn->mask,-1,outvn)) return false;
      hcount += 1;		// Dealt with this descendant
      break;
    case CPUI_INT_OR:
      if (doesOrSet(op,rvn->mask)!=-1) break; // Subvar set to 1s, truncate flow
      rop = createOpDown(CPUI_INT_OR,2,op,rvn,slot);
      if (!createLink(rop,rvn->mask,-1,outvn)) return false;
      hcount += 1;		// Dealt with this descendant
      break;
    case CPUI_INT_AND:
      if ((op->getIn(1)->isConstant())&&(op->getIn(1)->getOffset() == rvn->mask)) {
	if ((outvn->getSize() == flowsize)&&((rvn->mask & 1)!=0)) {
	  addTerminalPatch(op,rvn);
	  hcount += 1;		// Dealt with this descendant
	  break;
	}
	// Is the small variable getting zero padded into something that is fully consumed
	if ((!aggressive)&&((outvn->getConsume() & rvn->mask) != outvn->getConsume())) {
	  addSuggestedPatch(rvn,op,-1);
	  hcount += 1;		// Dealt with this descendant
	  break;
	}
      }
      if (doesAndClear(op,rvn->mask)!=-1) break; // Subvar set to zero, truncate flow
      rop = createOpDown(CPUI_INT_AND,2,op,rvn,slot);
      if (!createLink(rop,rvn->mask,-1,outvn)) return false;
      hcount += 1;		// Dealt with this descendant
      break;
    case CPUI_INT_ZEXT:
    case CPUI_INT_SEXT:
      rop = createOpDown(CPUI_COPY,1,op,rvn,0);
      if (!createLink(rop,rvn->mask,-1,outvn)) return false;
      hcount += 1;		// Dealt with this descendant
      break;
    case CPUI_INT_MULT:
      if ((rvn->mask & 1)==0)
	return false;		// Cannot account for carry
      sa = leastsigbit_set(op->getIn(1-slot)->getNZMask());
      sa &= ~7;			// Should be nearest multiple of 8
      if (bitsize + sa > 8*rvn->vn->getSize()) return false;
      rop = createOpDown(CPUI_INT_MULT,2,op,rvn,slot);
      if (!createLink(rop,rvn->mask<<sa,-1,outvn)) return false;
      hcount += 1;
      break;
    case CPUI_INT_ADD:
      if ((rvn->mask & 1)==0) 
	return false;		// Cannot account for carry
      rop = createOpDown(CPUI_INT_ADD,2,op,rvn,slot);
      if (!createLink(rop,rvn->mask,-1,outvn)) return false;
      hcount += 1;		// Dealt with this descendant
      break;
    case CPUI_INT_LEFT:
      if (slot == 1) {		// Logical flow is into shift amount
	if ((rvn->mask & 1)==0) return false;	// Cannot account for effect of extraneous bits
	if (bitsize <8) return false;
	// Its possible that truncating to the logical value could have an effect, if there were non-zero bits
	// being truncated.  Non-zero bits here would mean the shift-amount was very large (>255), indicating the
	// the result was undefined
	addTerminalPatchSameOp(op,rvn,slot);
	hcount += 1;
	break;
      }
      if (!op->getIn(1)->isConstant()) return false; // Dynamic shift
      sa = (int4)op->getIn(1)->getOffset();
      newmask = (rvn->mask << sa) & calc_mask( outvn->getSize() );
      if (newmask == 0) break;	// Subvar is cleared, truncate flow
      if (rvn->mask != (newmask >> sa)) return false; // subvar is clipped
	// Is the small variable getting zero padded into something that is fully consumed
      if (((rvn->mask & 1)!=0)&&(sa + bitsize == 8*outvn->getSize())
	  &&(calc_mask(outvn->getSize()) == outvn->getConsume())) {
	addSuggestedPatch(rvn,op,sa);
	hcount += 1;
	break;
      }
      rop = createOpDown(CPUI_COPY,1,op,rvn,0);
      if (!createLink(rop,newmask,-1,outvn)) return false;
      hcount += 1;		// Dealt with this descendant
      break;
    case CPUI_INT_RIGHT:
    case CPUI_INT_SRIGHT:
      if (slot == 1) {		// Logical flow is into shift amount
	if ((rvn->mask & 1)==0) return false;	// Cannot account for effect of extraneous bits
	if (bitsize <8) return false;
	addTerminalPatchSameOp(op,rvn,slot);
	hcount += 1;
	break;
      }
      if (!op->getIn(1)->isConstant()) return false;
      sa = (int4)op->getIn(1)->getOffset();
      newmask = rvn->mask >> sa;
      if (newmask == 0) {
	if (op->code()==CPUI_INT_RIGHT) break; // subvar is set to zero, truncate flow
	return false;
      }
      if (rvn->mask != (newmask << sa)) return false;
      if ((outvn->getSize()==flowsize)&&((newmask&1)==1)&&
	  (op->getIn(0)->getNZMask()==rvn->mask)) {
	addTerminalPatch(op,rvn);
	hcount += 1;		// Dealt with this descendant
	break;
      }
	// Is the small variable getting zero padded into something that is fully consumed
      if (((newmask&1)==1)&&(sa + bitsize == 8*outvn->getSize())
	  &&(calc_mask(outvn->getSize()) == outvn->getConsume())) {
	addSuggestedPatch(rvn,op,0);
	hcount += 1;
	break;
      }
      rop = createOpDown(CPUI_COPY,1,op,rvn,0);
      if (!createLink(rop,newmask,-1,outvn)) return false;
      hcount += 1;		// Dealt with this descendant
      break;
    case CPUI_SUBPIECE:
      sa = (int4)op->getIn(1)->getOffset() * 8;
      newmask = (rvn->mask >> sa) & calc_mask(outvn->getSize());
      if (newmask == 0) break;	// subvar is set to zero, truncate flow
      if (rvn->mask != (newmask << sa)) {	// Some kind of truncation of the logical value
	if (flowsize > ((sa/8) + outvn->getSize()) && (rvn->mask & 1) != 0) {
	  // Only a piece of the logical value remains
	  addTerminalPatchSameOp(op, rvn, 0);
	  hcount += 1;
	  break;
	}
	return false;
      }
      if (((newmask & 1)!=0)&&(outvn->getSize()==flowsize)) {
	addTerminalPatch(op,rvn);
	hcount += 1;		// Dealt with this descendant
	break;
      }
      rop = createOpDown(CPUI_COPY,1,op,rvn,0);
      if (!createLink(rop,newmask,-1,outvn)) return false;
      hcount += 1;		// Dealt with this descendant
      break;
    case CPUI_PIECE:
      if (rvn->vn == op->getIn(0))
	newmask = rvn->mask << (8*op->getIn(1)->getSize());
      else
	newmask = rvn->mask;
      rop = createOpDown(CPUI_COPY,1,op,rvn,0);
      if (!createLink(rop,newmask,-1,outvn)) return false;
      hcount += 1;		// Dealt with this descendant
      break;
    case CPUI_INT_LESS:
    case CPUI_INT_LESSEQUAL:
      outvn = op->getIn(1-slot); // The OTHER side of the comparison
      if ((!aggressive)&&(((rvn->vn->getNZMask() | rvn->mask) != rvn->mask)))
	return false;		// Everything but logical variable must definitely be zero (unless we are aggressive)
      if (outvn->isConstant()) {
	if ((rvn->mask | outvn->getOffset()) != rvn->mask)
	  return false;		// Must compare only bits of logical variable
      }
      else {
	if ((!aggressive)&&(((rvn->mask | outvn->getNZMask()) != rvn->mask))) // unused bits of otherside must be zero
	  return false;
      }
      if (!createCompareBridge(op,rvn,slot,outvn))
	return false;
      hcount += 1;		// Dealt with this descendant
      break;
    case CPUI_INT_NOTEQUAL:
    case CPUI_INT_EQUAL:
      outvn = op->getIn(1-slot); // The OTHER side of the comparison
      if (bitsize != 1) {
	if ((!aggressive)&&(((rvn->vn->getNZMask() | rvn->mask) != rvn->mask)))
	  return false;	// Everything but logical variable must definitely be zero (unless we are aggressive)
	if (outvn->isConstant()) {
	  if ((rvn->mask | outvn->getOffset()) != rvn->mask)
	    return false;	// Not comparing to just bits of the logical variable
	}
	else {
	  if ((!aggressive)&&(((rvn->mask | outvn->getNZMask()) != rvn->mask))) // unused bits must be zero
	    return false;
	}
	if (!createCompareBridge(op,rvn,slot,outvn))
	  return false;
      }
      else {			// Movement of boolean variables
	if (!outvn->isConstant()) return false;
	newmask = rvn->vn->getNZMask();
	if (newmask != rvn->mask) return false;
	if (op->getIn(1-slot)->getOffset() == (uintb)0)
	  booldir = true;
	else if (op->getIn(1-slot)->getOffset() == newmask)
	  booldir = false;
	else
	  return false;
	if (op->code() == CPUI_INT_EQUAL)
	  booldir = !booldir;
	if (booldir)
	  addTerminalPatch(op,rvn);
	else {
	  rop = createOpDown(CPUI_BOOL_NEGATE,1,op,rvn,0);
	  createNewOut(rop,(uintb)1);
	  addTerminalPatch(op,rop->output);
	}
      }
      hcount += 1;		// Dealt with this descendant
      break;
    case CPUI_CALL:
    case CPUI_CALLIND:
      callcount += 1;
      if (callcount > 1)
	slot = op->getRepeatSlot(rvn->vn, slot, iter);
      if (!tryCallPull(op,rvn,slot)) return false;
      hcount += 1;		// Dealt with this descendant
      break;
    case CPUI_RETURN:
      if (!tryReturnPull(op,rvn,slot)) return false;
      hcount += 1;
      break;
    case CPUI_BRANCHIND:
      if (!trySwitchPull(op, rvn)) return false;
      hcount += 1;
      break;
    case CPUI_BOOL_NEGATE:
    case CPUI_BOOL_AND:
    case CPUI_BOOL_OR:
    case CPUI_BOOL_XOR:
      if (bitsize != 1) return false;
      if (rvn->mask != 1) return false;
      addBooleanPatch(op,rvn,slot);
      break;
    case CPUI_CBRANCH:
      if ((bitsize != 1)||(slot != 1)) return false;
      if (rvn->mask != 1) return false;
      addBooleanPatch(op,rvn,1);
      hcount += 1;
      break;
    default:
      return false;
    }
  }
  if (dcount != hcount) {
    // Must account for all descendants of an input
    if (rvn->vn->isInput()) return false;
  }
  return true;
}

/// Trace the logical value backward through one PcodeOp adding new nodes to the
/// logical subgraph and updating the worklist.
/// \param rvn is the given logical value to trace
/// \return \b true if the logical value can be traced backward one level
bool SubvariableFlow::traceBackward(ReplaceVarnode *rvn)

{
  PcodeOp *op = rvn->vn->getDef();
  if (op == (PcodeOp *)0) return true; // If vn is input
  int4 sa;
  uintb newmask;
  ReplaceOp *rop;

  switch(op->code()) {
  case CPUI_COPY:
  case CPUI_MULTIEQUAL:
  case CPUI_INT_NEGATE:
  case CPUI_INT_XOR:
    rop = createOp(op->code(),op->numInput(),rvn);
    for(int4 i=0;i<op->numInput();++i)
      if (!createLink(rop,rvn->mask,i,op->getIn(i))) // Same inputs and mask
	return false;
    return true;
  case CPUI_INT_AND:
    sa = doesAndClear(op,rvn->mask);
    if (sa != -1) {
      rop = createOp(CPUI_COPY,1,rvn);
      addConstant(rop,rvn->mask,0,op->getIn(sa));
    }
    else {
      rop = createOp(CPUI_INT_AND,2,rvn);
      if (!createLink(rop,rvn->mask,0,op->getIn(0))) return false;
      if (!createLink(rop,rvn->mask,1,op->getIn(1))) return false;
    }
    return true;
  case CPUI_INT_OR:
    sa = doesOrSet(op,rvn->mask);
    if (sa != -1) {
      rop = createOp(CPUI_COPY,1,rvn);
      addConstant(rop,rvn->mask,0,op->getIn(sa));
    }
    else {
      rop = createOp(CPUI_INT_OR,2,rvn);
      if (!createLink(rop,rvn->mask,0,op->getIn(0))) return false;
      if (!createLink(rop,rvn->mask,1,op->getIn(1))) return false;
    }
    return true;
  case CPUI_INT_ZEXT:
  case CPUI_INT_SEXT:
    if ((rvn->mask & calc_mask(op->getIn(0)->getSize())) != rvn->mask) {
      if ((rvn->mask & 1)!=0 && flowsize > op->getIn(0)->getSize()) {
	addPush(op,rvn);
	return true;
      }
      break;	       // Check if subvariable comes through extension
    }
    rop = createOp(CPUI_COPY,1,rvn);
    if (!createLink(rop,rvn->mask,0,op->getIn(0))) return false;
    return true;
  case CPUI_INT_ADD:
    if ((rvn->mask & 1)==0)
      break;			// Cannot account for carry
    if (rvn->mask == (uintb)1)
      rop = createOp(CPUI_INT_XOR,2,rvn); // Single bit add
    else
      rop = createOp(CPUI_INT_ADD,2,rvn);
    if (!createLink(rop,rvn->mask,0,op->getIn(0))) return false;
    if (!createLink(rop,rvn->mask,1,op->getIn(1))) return false;
    return true;
  case CPUI_INT_LEFT:
    if (!op->getIn(1)->isConstant()) break; // Dynamic shift
    sa = (int4)op->getIn(1)->getOffset();
    newmask = rvn->mask >> sa;	// What mask looks like before shift
    if (newmask == 0) {		// Subvariable filled with shifted zero
      rop = createOp(CPUI_COPY,1,rvn);
      addNewConstant(rop,0,(uintb)0);
      return true;
    }
    if ((newmask<<sa) != rvn->mask)
      break;			// subvariable is truncated by shift
    rop = createOp(CPUI_COPY,1,rvn);
    if (!createLink(rop,newmask,0,op->getIn(0))) return false;
    return true;
  case CPUI_INT_RIGHT:
    if (!op->getIn(1)->isConstant()) break; // Dynamic shift
    sa = (int4)op->getIn(1)->getOffset();
    newmask = (rvn->mask << sa) & calc_mask(op->getIn(0)->getSize());
    if (newmask == 0) {		// Subvariable filled with shifted zero
      rop = createOp(CPUI_COPY,1,rvn);
      addNewConstant(rop,0,(uintb)0);
      return true;
    }
    if ((newmask>>sa) != rvn->mask)
      break;			// subvariable is truncated by shift
    rop = createOp(CPUI_COPY,1,rvn);
    if (!createLink(rop,newmask,0,op->getIn(0))) return false;
    return true;
  case CPUI_INT_SRIGHT:
    if (!op->getIn(1)->isConstant()) break; // Dynamic shift
    sa = (int4)op->getIn(1)->getOffset();
    newmask = (rvn->mask << sa) & calc_mask(op->getIn(0)->getSize());
    if ((newmask>>sa) != rvn->mask)
      break;			// subvariable is truncated by shift
    rop = createOp(CPUI_COPY,1,rvn);
    if (!createLink(rop,newmask,0,op->getIn(0))) return false;
    return true;
  case CPUI_INT_MULT:
    sa = leastsigbit_set(rvn->mask);
    if (sa!=0) {
      int4 sa2 = leastsigbit_set(op->getIn(1)->getNZMask());
      if (sa2 < sa) return false; // Cannot deal with carries into logical multiply
      newmask = rvn->mask >> sa;
      rop = createOp(CPUI_INT_MULT,2,rvn);
      if (!createLink(rop,newmask,0,op->getIn(0))) return false;
      if (!createLink(rop,rvn->mask,1,op->getIn(1))) return false;
    }
    else {
      if (rvn->mask == (uintb)1)
	rop = createOp(CPUI_INT_AND,2,rvn); // Single bit multiply
      else
	rop = createOp(CPUI_INT_MULT,2,rvn);
      if (!createLink(rop,rvn->mask,0,op->getIn(0))) return false;
      if (!createLink(rop,rvn->mask,1,op->getIn(1))) return false;
    }
    return true;
  case CPUI_SUBPIECE:
    sa = (int4)op->getIn(1)->getOffset() * 8;
    newmask = rvn->mask << sa;
    rop = createOp(CPUI_COPY,1,rvn);
    if (!createLink(rop,newmask,0,op->getIn(0))) return false;
    return true;
  case CPUI_PIECE:
    if ((rvn->mask & calc_mask(op->getIn(1)->getSize()))==rvn->mask) {
      rop = createOp(CPUI_COPY,1,rvn);
      if (!createLink(rop,rvn->mask,0,op->getIn(1))) return false;
      return true;
    }
    sa = op->getIn(1)->getSize() * 8;
    newmask = rvn->mask>>sa;
    if (newmask<<sa == rvn->mask) {
      rop = createOp(CPUI_COPY,1,rvn);
      if (!createLink(rop,newmask,0,op->getIn(0))) return false;
      return true;
    }
    break;
  case CPUI_CALL:
  case CPUI_CALLIND:
    if (tryCallReturnPush(op,rvn))
      return true;
    break;
  case CPUI_INT_EQUAL:
  case CPUI_INT_NOTEQUAL:
  case CPUI_INT_SLESS:
  case CPUI_INT_SLESSEQUAL:
  case CPUI_INT_LESS:
  case CPUI_INT_LESSEQUAL:
  case CPUI_INT_CARRY:
  case CPUI_INT_SCARRY:
  case CPUI_INT_SBORROW:
  case CPUI_BOOL_NEGATE:
  case CPUI_BOOL_XOR:
  case CPUI_BOOL_AND:
  case CPUI_BOOL_OR:
  case CPUI_FLOAT_EQUAL:
  case CPUI_FLOAT_NOTEQUAL:
  case CPUI_FLOAT_LESSEQUAL:
  case CPUI_FLOAT_NAN:
    // Mask won't be 1, because setReplacement takes care of it
    if ((rvn->mask&1)==1) break; // Not normal variable flow
    // Variable is filled with zero
    rop = createOp(CPUI_COPY,1,rvn);
    addNewConstant(rop,0,(uintb)0);
    return true;
  default:
    break;			// Everything else we abort
  }
  
  return false;
}

/// Try to trace the logical variable through descendant Varnodes, updating the logical subgraph.
/// We assume (and check) that the logical variable has always been sign extended (sextstate) into its container.
/// \param rvn is the given subgraph variable to trace
/// \return \b true if the logical value can successfully traced forward one level
bool SubvariableFlow::traceForwardSext(ReplaceVarnode *rvn)

{
  ReplaceOp *rop;
  PcodeOp *op;
  Varnode *outvn;
  int4 slot;
  int4 dcount = 0;
  int4 hcount = 0;
  int4 callcount = 0;

  list<PcodeOp *>::const_iterator iter,enditer;
  enditer = rvn->vn->endDescend();
  for(iter=rvn->vn->beginDescend();iter != enditer;++iter) {
    op = *iter;
    outvn = op->getOut();
    if ((outvn!=(Varnode *)0)&&outvn->isMark()&&!op->isCall())
      continue;
    dcount += 1;		// Count this descendant
    slot = op->getSlot(rvn->vn);
    switch(op->code()) {
    case CPUI_COPY:
    case CPUI_MULTIEQUAL:
    case CPUI_INT_NEGATE:
    case CPUI_INT_XOR:
    case CPUI_INT_OR:
    case CPUI_INT_AND:
      rop = createOpDown(op->code(),op->numInput(),op,rvn,slot);
      if (!createLink(rop,rvn->mask,-1,outvn)) return false;
      hcount += 1;
      break;
    case CPUI_INT_SEXT:		// extended logical variable into even larger container
      rop = createOpDown(CPUI_COPY,1,op,rvn,0);
      if (!createLink(rop,rvn->mask,-1,outvn)) return false;
      hcount += 1;
      break;
    case CPUI_INT_SRIGHT:
      if (!op->getIn(1)->isConstant()) return false; // Right now we only deal with constant shifts
      rop = createOpDown(CPUI_INT_SRIGHT,2,op,rvn,0);
      if (!createLink(rop,rvn->mask,-1,outvn)) return false; // Keep the same mask size
      addConstant(rop,calc_mask(op->getIn(1)->getSize()),1,op->getIn(1)); // Preserve the shift amount
      hcount += 1;
      break;
    case CPUI_SUBPIECE:
      if (op->getIn(1)->getOffset() != 0) return false;	// Only allow proper truncation
      if (outvn->getSize() > flowsize) return false;
      if (outvn->getSize() == flowsize)
	addTerminalPatch(op,rvn);		// Termination of flow, convert SUBPIECE to COPY
      else
	addTerminalPatchSameOp(op,rvn,0);	// Termination of flow, SUBPIECE truncates even more
      hcount +=1;
      break;
    case CPUI_INT_LESS:		// Unsigned comparisons are equivalent at the 2 sizes on sign extended values
    case CPUI_INT_LESSEQUAL:
    case CPUI_INT_SLESS:
    case CPUI_INT_SLESSEQUAL:
    case CPUI_INT_EQUAL:	// Everything works if both sides are sign extended
    case CPUI_INT_NOTEQUAL:
      outvn = op->getIn(1-slot); // The OTHER side of the comparison
      if (!createCompareBridge(op,rvn,slot,outvn)) return false;
      hcount += 1;
      break;
    case CPUI_CALL:
    case CPUI_CALLIND:
      callcount += 1;
      if (callcount > 1)
	slot = op->getRepeatSlot(rvn->vn, slot, iter);
      if (!tryCallPull(op,rvn,slot)) return false;
      hcount += 1;		// Dealt with this descendant
      break;
    case CPUI_RETURN:
      if (!tryReturnPull(op,rvn,slot)) return false;
      hcount += 1;
      break;
    case CPUI_BRANCHIND:
      if (!trySwitchPull(op,rvn)) return false;
      hcount += 1;
      break;
    default:
      return false;
    }
  }
  if (dcount != hcount) {
    // Must account for all descendants of an input
    if (rvn->vn->isInput()) return false;
  }
  return true;
}

/// Try to trace the logical variable up through its defining op, updating the logical subgraph.
/// We assume (and check) that the logical variable has always been sign extended (sextstate) into its container.
/// \param rvn is the given subgraph variable to trace
/// \return \b true if the logical value can successfully traced backward one level
bool SubvariableFlow::traceBackwardSext(ReplaceVarnode *rvn)

{
  PcodeOp *op = rvn->vn->getDef();
  if (op == (PcodeOp *)0) return true; // If vn is input
  ReplaceOp *rop;

  switch(op->code()) {
  case CPUI_COPY:
  case CPUI_MULTIEQUAL:
  case CPUI_INT_NEGATE:
  case CPUI_INT_XOR:
  case CPUI_INT_AND:
  case CPUI_INT_OR:
    rop = createOp(op->code(),op->numInput(),rvn);
    for(int4 i=0;i<op->numInput();++i)
      if (!createLink(rop,rvn->mask,i,op->getIn(i))) // Same inputs and mask
	return false;
    return true;
  case CPUI_INT_ZEXT:
    if (op->getIn(0)->getSize() < flowsize) {
      // zero extension from a smaller size still acts as a signed extension
      addPush(op,rvn);
      return true;
    }
    break;
  case CPUI_INT_SEXT:
    if (flowsize != op->getIn(0)->getSize()) return false;
    rop = createOp(CPUI_COPY,1,rvn);
    if (!createLink(rop,rvn->mask,0,op->getIn(0))) return false;
    return true;
  case CPUI_INT_SRIGHT:
    // A sign-extended logical value is arithmetically right-shifted
    // we can replace with the logical value, keeping the same shift amount
    if (!op->getIn(1)->isConstant()) return false;
    rop = createOp(CPUI_INT_SRIGHT,2,rvn);
    if (!createLink(rop,rvn->mask,0,op->getIn(0))) return false; // Keep the same mask
    if (rop->input.size()==1)
      addConstant(rop,calc_mask(op->getIn(1)->getSize()),1,op->getIn(1)); // Preserve the shift amount
    return true;
  case CPUI_CALL:
  case CPUI_CALLIND:
    if (tryCallReturnPush(op,rvn))
      return true;
    break;
  default:
    break;
  }
  return false;
}

/// \brief Add a new variable to the logical subgraph as an input to the given operation
///
/// The subgraph is extended by the specified input edge, and a new variable node is created
/// if necessary or a preexisting node corresponding to the Varnode is used.
/// If the logical value described by the given mask cannot be made to line up with the
/// subgraph variable node, \b false is returned.
/// \param rop is the given operation
/// \param mask is the mask describing the logical value within the input Varnode
/// \param slot is the input slot of the Varnode to the operation
/// \param vn is the original input Varnode holding the logical value
/// \return \b true is the subgraph is successfully extended to the input
bool SubvariableFlow::createLink(ReplaceOp *rop,uintb mask,int4 slot,Varnode *vn)

{
  bool inworklist;
  ReplaceVarnode *rep = setReplacement(vn,mask,inworklist);
  if (rep == (ReplaceVarnode *)0) return false;

  if (rop != (ReplaceOp *)0) {
    if (slot == -1) {
      rop->output = rep;
      rep->def = rop;
    }
    else {
      while(rop->input.size() <= slot)
	rop->input.push_back((ReplaceVarnode *)0);
      rop->input[slot] = rep;
    }
  }

  if (inworklist)
    worklist.push_back(rep);
  return true;
}

/// \brief Extend the logical subgraph through a given comparison operator if possible
///
/// Given the variable already in the subgraph that is compared and the other side of the
/// comparison, add the other side as a logical value to the subgraph and create a PatchRecord
/// for the comparison operation.
/// \param op is the given comparison operation
/// \param inrvn is the variable already in the logical subgraph
/// \param slot is the input slot to the comparison of the variable already in the subgraph
/// \param othervn is the Varnode holding the other side of the comparison
/// \return \b true if the logical subgraph can successfully be extended through the comparison
bool SubvariableFlow::createCompareBridge(PcodeOp *op,ReplaceVarnode *inrvn,int4 slot,Varnode *othervn)

{
  bool inworklist;
  ReplaceVarnode *rep = setReplacement(othervn,inrvn->mask,inworklist);
  if (rep == (ReplaceVarnode *)0) return false;

  if (slot==0)
    addComparePatch(inrvn,rep,op);
  else
    addComparePatch(rep,inrvn,op);

  if (inworklist)
    worklist.push_back(rep);
  return true;
}

/// \brief Add a constant variable node to the logical subgraph
///
/// \param rop is the logical operation taking the constant as input
/// \param mask is the set of bits holding the logical value (within a bigger value)
/// \param slot is the input slot to the operation
/// \param constvn is the original constant
/// \return the new constant variable node
SubvariableFlow::ReplaceVarnode *SubvariableFlow::addConstant(ReplaceOp *rop,uintb mask,
					      uint4 slot,Varnode *constvn)
{
  newvarlist.emplace_back();
  ReplaceVarnode *res = &newvarlist.back();
  res->vn = constvn;
  res->replacement = (Varnode *)0;
  res->mask = mask;

  // Calculate the actual constant value
  int4 sa = leastsigbit_set(mask);
  res->val = (mask & constvn->getOffset()) >> sa;
  res->def = (ReplaceOp *)0;
  if (rop != (ReplaceOp *)0) {
    while(rop->input.size() <= slot)
      rop->input.push_back((ReplaceVarnode *)0);
    rop->input[slot] = res;
  }
  return res;
}

/// \brief Add a new constant variable node as an input to a logical operation.
///
/// The constant is new and isn't associated with a constant in the original graph.
/// \param rop is the logical operation taking the constant as input
/// \param slot is the input slot to the operation
/// \param val is the constant value
/// \return the new constant variable node
SubvariableFlow::ReplaceVarnode *SubvariableFlow::addNewConstant(ReplaceOp *rop,uint4 slot,uintb val)

{
  newvarlist.emplace_back();
  ReplaceVarnode *res = &newvarlist.back();
  res->vn = (Varnode *)0;
  res->replacement = (Varnode *)0;
  res->mask = 0;
  res->val = val;
  res->def = (ReplaceOp *)0;
  if (rop != (ReplaceOp *)0) {
    while(rop->input.size() <= slot)
      rop->input.push_back((ReplaceVarnode *)0);
    rop->input[slot] = res;
  }
  return res;
}

/// \brief Create a new, non-shadowing, subgraph variable node as an operation output
///
/// The new node does not shadow a preexisting Varnode. Because the ReplaceVarnode record
/// is defined by rop (the -def- field is filled in) this can still be distinguished from a constant.
/// \param rop is the logical operation taking the new output
/// \param mask describes the logical value
void SubvariableFlow::createNewOut(ReplaceOp *rop,uintb mask)

{
  newvarlist.emplace_back();
  ReplaceVarnode *res = &newvarlist.back();
  res->vn = (Varnode *)0;
  res->replacement = (Varnode *)0;
  res->mask = mask;

  rop->output = res;
  res->def = rop;
}

/// \brief Mark an operation where original data-flow is being pushed into a subgraph variable
///
/// The operation is not manipulating the logical value, but it produces a variable containing
/// the logical value. The original op will not change but will just produce a smaller value.
/// \param pushOp is the operation to mark
/// \param rvn is the output variable holding the logical value
void SubvariableFlow::addPush(PcodeOp *pushOp,ReplaceVarnode *rvn)

{
  patchlist.push_front(PatchRecord());		// Push to the front of the patch list
  patchlist.front().type = PatchRecord::push_patch;
  patchlist.front().patchOp = pushOp;
  patchlist.front().in1 = rvn;
}

/// \brief Mark an operation where a subgraph variable is naturally copied into the original data-flow
///
/// If the operations naturally takes the given logical value as input but the output
/// doesn't need to be traced as a logical value, a subgraph terminator (PatchRecord) is created
/// noting this. The original PcodeOp will be converted to a COPY.
/// \param pullop is the PcodeOp pulling the logical value out of the subgraph
/// \param rvn is the given subgraph variable holding the logical value
void SubvariableFlow::addTerminalPatch(PcodeOp *pullop,ReplaceVarnode *rvn)

{
  patchlist.emplace_back();
  patchlist.back().type = PatchRecord::copy_patch;	// Ultimately gets converted to a COPY
  patchlist.back().patchOp = pullop;	// Operation pulling the variable out
  patchlist.back().in1 = rvn;	// Point in container flow for pull
  pullcount += 1;		// a true terminal modification
}

/// \brief Mark an operation where a subgraph variable is naturally pulled into the original data-flow
///
/// If the operations naturally takes the given logical value as input but the output
/// doesn't need to be traced as a logical value, a subgraph terminator (PatchRecord) is created
/// noting this. The opcode of the operation will not change.
/// \param pullop is the PcodeOp pulling the logical value out of the subgraph
/// \param rvn is the given subgraph variable holding the logical value
/// \param slot is the input slot to the operation
void SubvariableFlow::addTerminalPatchSameOp(PcodeOp *pullop,ReplaceVarnode *rvn,int4 slot)

{
  patchlist.emplace_back();
  patchlist.back().type = PatchRecord::parameter_patch;	// Keep the original op, just change input
  patchlist.back().patchOp = pullop;	// Operation pulling the variable out
  patchlist.back().in1 = rvn;	// Point in container flow for pull
  patchlist.back().slot = slot;
  pullcount += 1;		// a true terminal modification
}

/// \brief Mark a subgraph bit variable flowing into an operation taking a boolean input
///
/// This doesn't count as a Varnode holding a logical value that needs to be patched (by itself).
/// A PatchRecord terminating the logical subgraph along the given edge is created.
/// \param pullop is the operation taking the boolean input
/// \param rvn is the given bit variable
/// \param slot is the input slot of the variable to the operation
void SubvariableFlow::addBooleanPatch(PcodeOp *pullop,ReplaceVarnode *rvn,int4 slot)

{
  patchlist.emplace_back();
  patchlist.back().type = PatchRecord::parameter_patch;	// Make no change to the operator, just put in the new input
  patchlist.back().patchOp = pullop;	// Operation pulling the variable out
  patchlist.back().in1 = rvn;	// Point in container flow for pull
  patchlist.back().slot = slot;
  // this is not a true modification
}

/// \brief Mark a subgraph variable flowing to an operation that expands it by padding with zero bits.
///
/// Data-flow along the specified edge within the logical subgraph is terminated by added a PatchRecord.
/// This doesn't count as a logical value that needs to be patched (by itself).
/// \param rvn is the given subgraph variable
/// \param pushop is the operation that pads the variable
/// \param sa is the amount the logical value is shifted to the left
void SubvariableFlow::addSuggestedPatch(ReplaceVarnode *rvn,PcodeOp *pushop,int4 sa)

{
  patchlist.emplace_back();
  patchlist.back().type = PatchRecord::extension_patch;
  patchlist.back().in1 = rvn;
  patchlist.back().patchOp = pushop;
  if (sa == -1)
    sa = leastsigbit_set(rvn->mask);
  patchlist.back().slot = sa;
  // This is not a true modification because the output is still the expanded size
}

/// \brief Mark subgraph variables flowing into a comparison operation
///
/// The operation accomplishes the logical comparison by comparing the larger containers.
/// A PatchRecord is created indicating that data-flow from the subgraph terminates at the comparison.
/// \param in1 is the first logical value to the comparison
/// \param in2 is the second logical value
/// \param op is the comparison operation
void SubvariableFlow::addComparePatch(ReplaceVarnode *in1,ReplaceVarnode *in2,PcodeOp *op)

{
  patchlist.emplace_back();
  patchlist.back().type = PatchRecord::compare_patch;
  patchlist.back().patchOp = op;
  patchlist.back().in1 = in1;
  patchlist.back().in2 = in2;
  pullcount += 1;
}

/// \brief Replace an input Varnode in the subgraph with a temporary register
///
/// This is used to avoid overlapping input Varnode errors. The temporary register
/// is typically short lived and gets quickly eliminated in favor of the new
/// logically sized Varnode.
/// \param rvn is the logical variable to replace
void SubvariableFlow::replaceInput(ReplaceVarnode *rvn)

{
  Varnode *newvn = fd->newUnique(rvn->vn->getSize());
  newvn = fd->setInputVarnode(newvn);
  fd->totalReplace(rvn->vn,newvn);
  fd->deleteVarnode(rvn->vn);
  rvn->vn = newvn;
}

/// \brief Decide if we use the same memory range of the original Varnode for the logical replacement
///
/// Usually the logical Varnode can use the \e true storage bytes that hold the value,
/// but there are a few corner cases where we want to use a new temporary register to hold the value.
/// \param rvn is the subgraph variable
/// \return \b true if the same memory range can be used to hold the value
bool SubvariableFlow::useSameAddress(ReplaceVarnode *rvn)

{
  if (rvn->vn->isInput()) return true;
  // If we trim an addrtied varnode, because of required merges, we increase chance of conflicting forms for one variable
  if (rvn->vn->isAddrTied()) return false;
  if ((rvn->mask&1)==0) return false; // Not aligned
  if (bitsize >= 8) return true;
  if (aggressive) return true;
  uint4 bitmask = 1;
  // Try to decide if this is the ONLY subvariable passing through
  // this container
  bitmask = (bitmask<<bitsize)-1;
  uintb mask = rvn->vn->getConsume();
  mask |= (uintb)bitmask;
  if (mask == rvn->mask) return true;
  return false;			// If more of the varnode is consumed than is in just this flow
}

/// \brief Calculcate address of replacement Varnode for given subgraph variable node
///
/// \param rvn is the given subgraph variable node
/// \return the address of the new logical Varnode
Address SubvariableFlow::getReplacementAddress(ReplaceVarnode *rvn) const

{
  Address addr = rvn->vn->getAddr();
  int4 sa = leastsigbit_set(rvn->mask) / 8; // Number of bytes value is shifted into container
  if (addr.isBigEndian())
    addr = addr + (rvn->vn->getSize() - flowsize - sa);
  else
    addr = addr + sa;
  addr.renormalize(flowsize);
  return addr;
}

/// \brief Build the logical Varnode which will replace its original containing Varnode
///
/// This is the main routine for converting a logical variable in the subgraph into
/// an actual Varnode object.
/// \param rvn is the logical variable
/// \return the (new or existing) Varnode object
Varnode *SubvariableFlow::getReplaceVarnode(ReplaceVarnode *rvn)

{
  if (rvn->replacement != (Varnode *)0)
    return rvn->replacement;
  if (rvn->vn == (Varnode *)0) {
    if (rvn->def==(ReplaceOp *)0) // A constant that did not come from an original Varnode
      return fd->newConstant(flowsize,rvn->val);
    rvn->replacement = fd->newUnique(flowsize);
    return rvn->replacement;
  }
  if (rvn->vn->isConstant()) {
    Varnode *newVn = fd->newConstant(flowsize,rvn->val);
    newVn->copySymbolIfValid(rvn->vn);
    return newVn;
  }

  bool isinput = rvn->vn->isInput();
  if (useSameAddress(rvn)) {
    Address addr = getReplacementAddress(rvn);
    if (isinput)
      replaceInput(rvn);	// Replace input to avoid overlap errors
    rvn->replacement = fd->newVarnode(flowsize,addr);
  }
  else
    rvn->replacement = fd->newUnique(flowsize);
  if (isinput)	// Is this an input
    rvn->replacement = fd->setInputVarnode(rvn->replacement);
  return rvn->replacement;
}

/// The subgraph is extended from the variable node at the top of the worklist.
/// Data-flow is traced forward and backward one level, possibly extending the subgraph
/// and adding new nodes to the worklist.
/// \return \b true if the node was successfully processed
bool SubvariableFlow::processNextWork(void)

{
  ReplaceVarnode *rvn = worklist.back();

  worklist.pop_back();

  if (sextrestrictions) {
    if (!traceBackwardSext(rvn)) return false;
    return traceForwardSext(rvn);
  }
  if (!traceBackward(rvn)) return false;
  return traceForward(rvn);
}

/// \param f is the function to attempt the subvariable transform on
/// \param root is a starting Varnode containing a smaller logical value
/// \param mask is a mask where 1 bits indicate the position of the logical value within the \e root Varnode
/// \param aggr is \b true if we should use aggressive (less restrictive) tests during the trace
/// \param sext is \b true if we should assume sign extensions from the logical value into its container
/// \param big is \b true if we look for subvariable flow for \e big (8-byte) logical values
SubvariableFlow::SubvariableFlow(Funcdata *f,Varnode *root,uintb mask,bool aggr,bool sext,bool big)

{
  fd = f;
  returnsTraversed = false;
  if (mask == (uintb)0) {
    fd = (Funcdata *)0;
    return;
  }
  aggressive = aggr;
  sextrestrictions = sext;
  bitsize = (mostsigbit_set(mask)-leastsigbit_set(mask))+1;
  if (bitsize <= 8)
    flowsize = 1;
  else if (bitsize <= 16)
    flowsize = 2;
  else if (bitsize <= 24)
    flowsize = 3;
  else if (bitsize <= 32)
    flowsize = 4;
  else if (bitsize <= 64) {
    if (!big) {
      fd = (Funcdata *)0;
      return;
    }
    flowsize = 8;
  }
  else {
    fd = (Funcdata *)0;
    return;
  }
  createLink((ReplaceOp *)0,mask,0,root);
}

/// Push the logical value around, setting up explicit transforms as we go that convert them
/// into explicit Varnodes. If at any point, we cannot naturally interpret the flow of the
/// logical value, return \b false.
/// \return \b true if a full transform has been constructed that can make logical values into explicit Varnodes
bool SubvariableFlow::doTrace(void)

{
  pullcount = 0;
  bool retval = false;
  if (fd != (Funcdata *)0) {
    retval = true;
    while(!worklist.empty()) {
      if (!processNextWork()) {
	retval = false;
	break;
      }
    }
  }

  // Clear marks
  map<Varnode *,ReplaceVarnode>::iterator iter;
  for(iter=varmap.begin();iter!=varmap.end();++iter)
    (*iter).first->clearMark();

  if (!retval) return false;
  if (pullcount == 0) return false;
  return true;
}

void SubvariableFlow::doReplacement(void)

{
  list<PatchRecord>::iterator piter;
  list<ReplaceOp>::iterator iter;

  // Do up front processing of the call return patches, which will be at the front of the list
  for(piter=patchlist.begin();piter!=patchlist.end();++piter) {
    if ((*piter).type != PatchRecord::push_patch) break;
    PcodeOp *pushOp = (*piter).patchOp;
    Varnode *newVn = getReplaceVarnode((*piter).in1);
    Varnode *oldVn = pushOp->getOut();
    fd->opSetOutput(pushOp, newVn);

    // Create placeholder defining op for old Varnode, until dead code cleans it up
    PcodeOp *newZext = fd->newOp(1, pushOp->getAddr());
    fd->opSetOpcode(newZext, CPUI_INT_ZEXT);
    fd->opSetInput(newZext,newVn,0);
    fd->opSetOutput(newZext,oldVn);
    fd->opInsertAfter(newZext, pushOp);
  }

  // Define all the outputs first
  for(iter=oplist.begin();iter!=oplist.end();++iter) {
    PcodeOp *newop = fd->newOp((*iter).numparams,(*iter).op->getAddr());
    (*iter).replacement = newop;
    fd->opSetOpcode(newop,(*iter).opc);
    ReplaceVarnode *rout = (*iter).output;
    //      if (rout != (ReplaceVarnode *)0) {
    //	if (rout->replacement == (Varnode *)0)
    //	  rout->replacement = fd->newUniqueOut(flowsize,newop);
    //	else
    //	  fd->opSetOutput(newop,rout->replacement);
    //      }
    fd->opSetOutput(newop,getReplaceVarnode(rout));
    fd->opInsertAfter(newop,(*iter).op);
  }

  // Set all the inputs
  for(iter=oplist.begin();iter!=oplist.end();++iter) {
    PcodeOp *newop = (*iter).replacement;
    for(uint4 i=0;i<(*iter).input.size();++i)
      fd->opSetInput(newop,getReplaceVarnode((*iter).input[i]),i);
  }

  // These are operations that carry flow from the small variable into an existing
  // variable of the correct size
  for(;piter!=patchlist.end();++piter) {
    PcodeOp *pullop = (*piter).patchOp;
    switch((*piter).type) {
    case PatchRecord::copy_patch:
      while(pullop->numInput() > 1)
	fd->opRemoveInput(pullop,pullop->numInput()-1);
      fd->opSetInput(pullop,getReplaceVarnode((*piter).in1),0);
      fd->opSetOpcode(pullop,CPUI_COPY);
      break;
    case PatchRecord::compare_patch:
      fd->opSetInput(pullop,getReplaceVarnode((*piter).in1),0);
      fd->opSetInput(pullop,getReplaceVarnode((*piter).in2),1);
      break;
    case PatchRecord::parameter_patch:
      fd->opSetInput(pullop,getReplaceVarnode((*piter).in1),(*piter).slot);
      break;
    case PatchRecord::extension_patch:
      {
	// These are operations that flow the small variable into a bigger variable but
	// where all the remaining bits are zero
	int4 sa = (*piter).slot;
	vector<Varnode *> invec;
	Varnode *inVn = getReplaceVarnode((*piter).in1);
	int4 outSize = pullop->getOut()->getSize();
	if (sa == 0) {
	  invec.push_back(inVn);
	  OpCode opc = (inVn->getSize() == outSize) ? CPUI_COPY : CPUI_INT_ZEXT;
	  fd->opSetOpcode(pullop, opc);
	  fd->opSetAllInput(pullop, invec);
	}
	else {
	  if (inVn->getSize() != outSize) {
	    PcodeOp *zextop = fd->newOp(1, pullop->getAddr());
	    fd->opSetOpcode(zextop, CPUI_INT_ZEXT);
	    Varnode *zextout = fd->newUniqueOut(outSize, zextop);
	    fd->opSetInput(zextop, inVn, 0);
	    fd->opInsertBefore(zextop, pullop);
	    invec.push_back(zextout);
	  }
	  else
	    invec.push_back(inVn);
	  invec.push_back(fd->newConstant(4, sa));
	  fd->opSetAllInput(pullop, invec);
	  fd->opSetOpcode(pullop, CPUI_INT_LEFT);
	}
	break;
      }
    case PatchRecord::push_patch:
      break;	// Shouldn't see these here, handled earlier
    }
  }
}

/// \brief Find or build the placeholder objects for a Varnode that needs to be split
///
/// Mark the Varnode so it doesn't get revisited.
/// Decide if the Varnode needs to go into the worklist.
/// \param vn is the Varnode that needs to be split
/// \return the array of placeholders describing the split or null
TransformVar *SplitFlow::setReplacement(Varnode *vn)

{
  TransformVar *res;
  if (vn->isMark()) {		// Already seen before
    res = getSplit(vn, laneDescription);
    return res;
  }

  if (vn->isTypeLock())
    return (TransformVar *)0;
  if (vn->isInput())
    return (TransformVar *)0;		// Right now we can't split inputs
  if (vn->isFree() && (!vn->isConstant()))
    return (TransformVar *)0;		// Abort

  res = newSplit(vn, laneDescription);	// Create new ReplaceVarnode and put it in map
  vn->setMark();
  if (!vn->isConstant())
    worklist.push_back(res);

  return res;
}

/// \brief Split given op into its lanes.
///
/// We assume op is a logical operation, or a COPY, or an INDIRECT. It must have an output.
/// All inputs and output have their placeholders generated and added to the worklist
/// if appropriate.
/// \param op is the given op
/// \param rvn is a known parameter of the op
/// \param slot is the incoming slot of the known parameter (-1 means parameter is output)
/// \return \b true if the op is successfully split
bool SplitFlow::addOp(PcodeOp *op,TransformVar *rvn,int4 slot)

{
  TransformVar *outvn;
  if (slot == -1)
    outvn = rvn;
  else {
    outvn = setReplacement(op->getOut());
    if (outvn == (TransformVar *)0)
      return false;
  }

  if (outvn->getDef() != (TransformOp *)0)
    return true;	// Already traversed

  TransformOp *loOp = newOpReplace(op->numInput(), op->code(), op);
  TransformOp *hiOp = newOpReplace(op->numInput(), op->code(), op);
  int4 numParam = op->numInput();
  if (op->code() == CPUI_INDIRECT) {
    opSetInput(loOp,newIop(op->getIn(1)),1);
    opSetInput(hiOp,newIop(op->getIn(1)),1);
    numParam = 1;
  }
  for(int4 i=0;i<numParam;++i) {
    TransformVar *invn;
    if (i == slot)
      invn = rvn;
    else {
      invn = setReplacement(op->getIn(i));
      if (invn == (TransformVar *)0)
	return false;
    }
    opSetInput(loOp,invn,i);		// Low piece with low op
    opSetInput(hiOp,invn+1,i);		// High piece with high op
  }
  opSetOutput(loOp,outvn);
  opSetOutput(hiOp,outvn+1);
  return true;
}

/// \brief Try to trace the pair of logical values, forward, through ops that read them
///
/// Try to trace pieces of TransformVar pair forward, through reading ops, update worklist
/// \param rvn is the TransformVar pair to trace, as an array
/// \return \b true if logical pieces can be naturally traced, \b false otherwise
bool SplitFlow::traceForward(TransformVar *rvn)

{
  Varnode *origvn = rvn->getOriginal();
  list<PcodeOp *>::const_iterator iter,enditer;
  iter = origvn->beginDescend();
  enditer = origvn->endDescend();
  while(iter != enditer) {
    PcodeOp *op = *iter++;
    Varnode *outvn = op->getOut();
    if ((outvn!=(Varnode *)0)&&(outvn->isMark()))
      continue;
    switch(op->code()) {
    case CPUI_COPY:
    case CPUI_MULTIEQUAL:
    case CPUI_INDIRECT:
    case CPUI_INT_AND:
    case CPUI_INT_OR:
    case CPUI_INT_XOR:
  //  case CPUI_INT_NEGATE:
      if (!addOp(op,rvn,op->getSlot(origvn)))
	return false;
      break;
    case CPUI_SUBPIECE:
    {
      if (outvn->isPrecisLo() || outvn->isPrecisHi())
	return false;		// Do not split if we know value comes from double precision pieces
      uintb val = op->getIn(1)->getOffset();
      if ((val==0)&&(outvn->getSize() == laneDescription.getSize(0))) {
	TransformOp *rop = newPreexistingOp(1,CPUI_COPY,op);	// Grabs the low piece
	opSetInput(rop, rvn, 0);
      }
      else if ((val == laneDescription.getSize(0))&&(outvn->getSize() == laneDescription.getSize(1))) {
	TransformOp *rop = newPreexistingOp(1,CPUI_COPY,op);	// Grabs the high piece
	opSetInput(rop, rvn+1, 0);
      }
      else
	return false;
      break;
    }
    case CPUI_INT_LEFT:
    {
      Varnode *tmpvn = op->getIn(1);
      if (!tmpvn->isConstant())
	return false;
      uintb val = tmpvn->getOffset();
      if (val < laneDescription.getSize(1) * 8)
	return false;			// Must obliterate all high bits
      TransformOp *rop = newPreexistingOp(2,CPUI_INT_LEFT,op);		// Keep original shift
      TransformOp *zextrop = newOp(1, CPUI_INT_ZEXT, rop);
      opSetInput(zextrop, rvn, 0);		// Input is just the low piece
      opSetOutput(zextrop, newUnique(laneDescription.getWholeSize()));
      opSetInput(rop, zextrop->getOut(), 0);
      opSetInput(rop, newConstant(op->getIn(1)->getSize(), 0, op->getIn(1)->getOffset()), 1);	// Original shift amount
      break;
    }
    case CPUI_INT_SRIGHT:
    case CPUI_INT_RIGHT:
    {
      Varnode *tmpvn = op->getIn(1);
      if (!tmpvn->isConstant())
	return false;
      uintb val = tmpvn->getOffset();
      if (val < laneDescription.getSize(0) * 8)
	return false;
      OpCode extOpCode = (op->code() == CPUI_INT_RIGHT) ? CPUI_INT_ZEXT : CPUI_INT_SEXT;
      if (val == laneDescription.getSize(0) * 8) {	// Shift of exactly loSize bytes
	TransformOp *rop = newPreexistingOp(1,extOpCode,op);
	opSetInput(rop, rvn+1, 0);	// Input is the high piece
      }
      else {
	uintb remainShift = val - laneDescription.getSize(0) * 8;
	TransformOp *rop = newPreexistingOp(2,op->code(),op);
	TransformOp *extrop = newOp(1, extOpCode, rop);
	opSetInput(extrop, rvn+1, 0);	// Input is the high piece
	opSetOutput(extrop, newUnique(laneDescription.getWholeSize()));
	opSetInput(rop, extrop->getOut(), 0);
	opSetInput(rop, newConstant(op->getIn(1)->getSize(), 0, remainShift), 1);	// Shift any remaining bits
      }
      break;
    }
    default:
      return false;
    }
  }
  return true;
}

/// \brief Try to trace the pair of logical values, backward, through the defining op
///
/// Create part of transform related to the defining op, and update the worklist as necessary.
/// \param rvn is the logical value to examine
/// \return \b false if the trace is not possible
bool SplitFlow::traceBackward(TransformVar *rvn)

{
  PcodeOp *op = rvn->getOriginal()->getDef();
  if (op == (PcodeOp *)0) return true; // If vn is input

  switch(op->code()) {
  case CPUI_COPY:
  case CPUI_MULTIEQUAL:
  case CPUI_INT_AND:
  case CPUI_INT_OR:
  case CPUI_INT_XOR:
  case CPUI_INDIRECT:
//  case CPUI_INT_NEGATE:
    if (!addOp(op,rvn,-1))
      return false;
    break;
  case CPUI_PIECE:
  {
    if (op->getIn(0)->getSize() != laneDescription.getSize(1))
      return false;
    if (op->getIn(1)->getSize() != laneDescription.getSize(0))
      return false;
    TransformOp *loOp = newOpReplace(1, CPUI_COPY, op);
    TransformOp *hiOp = newOpReplace(1, CPUI_COPY, op);
    opSetInput(loOp,getPreexistingVarnode(op->getIn(1)),0);
    opSetOutput(loOp,rvn);	// Least sig -> low
    opSetInput(hiOp,getPreexistingVarnode(op->getIn(0)),0);
    opSetOutput(hiOp,rvn+1);	// Most sig -> high
    break;
  }
  case CPUI_INT_ZEXT:
  {
    if (op->getIn(0)->getSize() != laneDescription.getSize(0))
      return false;
    if (op->getOut()->getSize() != laneDescription.getWholeSize())
      return false;
    TransformOp *loOp = newOpReplace(1, CPUI_COPY, op);
    TransformOp *hiOp = newOpReplace(1, CPUI_COPY, op);
    opSetInput(loOp,getPreexistingVarnode(op->getIn(0)),0);
    opSetOutput(loOp,rvn);	// ZEXT input -> low
    opSetInput(hiOp,newConstant(laneDescription.getSize(1), 0, 0), 0);
    opSetOutput(hiOp,rvn+1);	// zero -> high
    break;
  }
  case CPUI_INT_LEFT:
  {
    Varnode *cvn = op->getIn(1);
    if (!cvn->isConstant()) return false;
    if (cvn->getOffset() != laneDescription.getSize(0) * 8) return false;
    Varnode *invn = op->getIn(0);
    if (!invn->isWritten()) return false;
    PcodeOp *zextOp = invn->getDef();
    if (zextOp->code() != CPUI_INT_ZEXT) return false;
    invn = zextOp->getIn(0);
    if (invn->getSize() != laneDescription.getSize(1)) return false;
    if (invn->isFree()) return false;
    TransformOp *loOp = newOpReplace(1, CPUI_COPY, op);
    TransformOp *hiOp = newOpReplace(1, CPUI_COPY, op);
    opSetInput(loOp,newConstant(laneDescription.getSize(0), 0, 0), 0);
    opSetOutput(loOp, rvn);	// zero -> low
    opSetInput(hiOp,getPreexistingVarnode(invn), 0);
    opSetOutput(hiOp, rvn+1);	// invn -> high
    break;
  }
//  case CPUI_LOAD:		// We could split into two different loads
  default:
    return false;
  }
  return true;
}

/// \return \b true if the logical split was successfully pushed through its local operators
bool SplitFlow::processNextWork(void)

{
  TransformVar *rvn = worklist.back();

  worklist.pop_back();

  if (!traceBackward(rvn)) return false;
  return traceForward(rvn);
}

SplitFlow::SplitFlow(Funcdata *f,Varnode *root,int4 lowSize)
  : TransformManager(f), laneDescription(root->getSize(),lowSize,root->getSize()-lowSize)

{
  setReplacement(root);
}

/// Push the logical split around, setting up the explicit transforms as we go.
/// If at any point, the split cannot be naturally pushed, return \b false.
/// \return \b true if a full transform has been constructed that can perform the split
bool SplitFlow::doTrace(void)

{
  if (worklist.empty())
    return false;		// Nothing to do
  bool retval = true;
  while(!worklist.empty()) {	// Process the worklist until its done
    if (!processNextWork()) {
      retval = false;
      break;
    }
  }

  clearVarnodeMarks();
  if (!retval) return false;
  return true;
}

/// \brief Create and return a placeholder associated with the given Varnode
///
/// Add the placeholder to the worklist if it hasn't been visited before
/// \param vn is the given Varnode
/// \return the placeholder or null if the Varnode is not suitable for replacement
TransformVar *SubfloatFlow::setReplacement(Varnode *vn)

{
  if (vn->isMark())		// Already seen before
    return getPiece(vn, precision*8, 0);

  if (vn->isConstant()) {
    const FloatFormat *form2 = getFunction()->getArch()->translate->getFloatFormat(vn->getSize());
    if (form2 == (const FloatFormat *)0)
      return (TransformVar *)0;	// Unsupported constant format
    // Return the converted form of the constant
    return newConstant(precision, 0, format->convertEncoding(vn->getOffset(),form2));
  }

  if (vn->isFree())
    return (TransformVar *)0; // Abort

  if (vn->isAddrForce() && (vn->getSize() != precision))
    return (TransformVar *)0;

  if (vn->isTypeLock()) {
    int4 sz = vn->getType()->getSize();
    if (sz != precision)
      return (TransformVar *)0;
  }

  if (vn->isInput()) {		// Must be careful with inputs
    if (vn->getSize() != precision) return (TransformVar *)0;
  }

  vn->setMark();
  TransformVar *res;
  // Check if vn already represents the logical variable being traced
  if (vn->getSize() == precision)
    res = newPreexistingVarnode(vn);
  else {
    res = newPiece(vn, precision*8, 0);
    worklist.push_back(res);
  }
  return res;
}

/// \brief Try to trace logical variable through descendant Varnodes
///
/// Given a Varnode placeholder, look at all descendent PcodeOps and create
/// placeholders for the op and its output Varnode.  If appropriate add the
/// output placeholder to the worklist.
/// \param rvn is the given Varnode placeholder
/// \return \b true if tracing the logical variable forward was possible
bool SubfloatFlow::traceForward(TransformVar *rvn)

{
  list<PcodeOp *>::const_iterator iter,enditer;
  Varnode *vn = rvn->getOriginal();
  iter = vn->beginDescend();
  enditer = vn->endDescend();
  while(iter != enditer) {
    PcodeOp *op = *iter++;
    Varnode *outvn = op->getOut();
    if ((outvn!=(Varnode *)0)&&(outvn->isMark()))
      continue;
    switch(op->code()) {
    case CPUI_COPY:
    case CPUI_FLOAT_CEIL:
    case CPUI_FLOAT_FLOOR:
    case CPUI_FLOAT_ROUND:
    case CPUI_FLOAT_NEG:
    case CPUI_FLOAT_ABS:
    case CPUI_FLOAT_SQRT:
    case CPUI_FLOAT_ADD:
    case CPUI_FLOAT_SUB:
    case CPUI_FLOAT_MULT:
    case CPUI_FLOAT_DIV:
    case CPUI_MULTIEQUAL:
    {
      TransformOp *rop = newOpReplace(op->numInput(), op->code(), op);
      TransformVar *outrvn = setReplacement(outvn);
      if (outrvn == (TransformVar *)0) return false;
      opSetInput(rop,rvn,op->getSlot(vn));
      opSetOutput(rop,outrvn);
      break;
    }
    case CPUI_FLOAT_FLOAT2FLOAT:
    {
      if (outvn->getSize() < precision)
	return false;
      TransformOp *rop = newPreexistingOp(1, (outvn->getSize() == precision) ? CPUI_COPY : CPUI_FLOAT_FLOAT2FLOAT, op);
      opSetInput(rop,rvn,0);
      terminatorCount += 1;
      break;
    }
    case CPUI_FLOAT_EQUAL:
    case CPUI_FLOAT_NOTEQUAL:
    case CPUI_FLOAT_LESS:
    case CPUI_FLOAT_LESSEQUAL:
    {
      int4 slot = op->getSlot(vn);
      TransformVar *rvn2 = setReplacement(op->getIn(1-slot));
      if (rvn2 == (TransformVar *)0) return false;
      if (rvn == rvn2) {
	list<PcodeOp *>::const_iterator ourIter = iter;
	--ourIter;	// Back up one to our original iterator
	slot = op->getRepeatSlot(vn, slot, ourIter);
      }
      if (preexistingGuard(slot, rvn2)) {
	TransformOp *rop = newPreexistingOp(2, op->code(), op);
	opSetInput(rop, rvn, 0);
	opSetInput(rop, rvn2, 1);
	terminatorCount += 1;
      }
      break;
    }
    case CPUI_FLOAT_TRUNC:
    case CPUI_FLOAT_NAN:
    {
      TransformOp *rop = newPreexistingOp(1,op->code(), op);
      opSetInput(rop,rvn,0);
      terminatorCount += 1;
      break;
    }
    default:
      return false;
    }
  }
  return true;
}

/// \brief Trace a logical value backward through defining op one level
///
/// Given an existing variable placeholder look at the op defining it and
/// define placeholder variables for all its inputs.  Put the new placeholders
/// onto the worklist if appropriate.
/// \param rvn is the given variable placeholder
/// \return \b true if the logical value can be traced properly
bool SubfloatFlow::traceBackward(TransformVar *rvn)

{
  PcodeOp *op = rvn->getOriginal()->getDef();
  if (op == (PcodeOp *)0) return true; // If vn is input

  switch(op->code()) {
  case CPUI_COPY:
  case CPUI_FLOAT_CEIL:
  case CPUI_FLOAT_FLOOR:
  case CPUI_FLOAT_ROUND:
  case CPUI_FLOAT_NEG:
  case CPUI_FLOAT_ABS:
  case CPUI_FLOAT_SQRT:
  case CPUI_FLOAT_ADD:
  case CPUI_FLOAT_SUB:
  case CPUI_FLOAT_MULT:
  case CPUI_FLOAT_DIV:
  case CPUI_MULTIEQUAL:
  {
    TransformOp *rop = rvn->getDef();
    if (rop == (TransformOp *)0) {
      rop = newOpReplace(op->numInput(), op->code(), op);
      opSetOutput(rop, rvn);
    }
    for(int4 i=0;i<op->numInput();++i) {
      TransformVar *newvar = rop->getIn(i);
      if (newvar == (TransformVar *)0) {
	newvar = setReplacement(op->getIn(i));
	if (newvar == (TransformVar *)0)
	  return false;
	opSetInput(rop,newvar,i);
      }
    }
    return true;
  }
  case CPUI_FLOAT_INT2FLOAT:
  {
    Varnode *vn = op->getIn(0);
    if (!vn->isConstant() && vn->isFree())
      return false;
    TransformOp *rop = newOpReplace(1, CPUI_FLOAT_INT2FLOAT, op);
    opSetOutput(rop, rvn);
    TransformVar *newvar = getPreexistingVarnode(vn);
    opSetInput(rop,newvar,0);
    return true;
  }
  case CPUI_FLOAT_FLOAT2FLOAT:
  {
    Varnode *vn = op->getIn(0);
    TransformVar *newvar;
    OpCode opc;
    if (vn->isConstant()) {
      opc = CPUI_COPY;
      if (vn->getSize() == precision)
	newvar = newConstant(precision, 0, vn->getOffset());
      else {
	newvar = setReplacement(vn);	// Convert constant to precision size
	if (newvar == (TransformVar *)0)
	  return false;			// Unsupported float format
      }
    }
    else {
      if (vn->isFree()) return false;
      opc = (vn->getSize() == precision) ? CPUI_COPY : CPUI_FLOAT_FLOAT2FLOAT;
      newvar = getPreexistingVarnode(vn);
    }
    TransformOp *rop = newOpReplace(1, opc, op);
    opSetOutput(rop, rvn);
    opSetInput(rop,newvar,0);
    return true;
  }
  default:
    break;			// Everything else we abort
  }
  
  return false;
}

/// \brief Push the trace one hop from the placeholder at the top of the worklist
///
/// The logical value for the value on top of the worklist stack is pushed back
/// to the input Varnodes of the operation defining it.  Then the value is pushed
/// forward through all operations that read it.
/// \return \b true if the trace is successfully pushed
bool SubfloatFlow::processNextWork(void)

{
  TransformVar *rvn = worklist.back();

  worklist.pop_back();

  if (!traceBackward(rvn)) return false;
  return traceForward(rvn);
}

/// \param f is the function being transformed
/// \param root is the start Varnode containing the logical value
/// \param prec is the precision to assume for the logical value
SubfloatFlow::SubfloatFlow(Funcdata *f,Varnode *root,int4 prec)
  : TransformManager(f)
{
  precision = prec;
  format = f->getArch()->translate->getFloatFormat(precision);
  if (format == (const FloatFormat *)0)
    return;
  setReplacement(root);
}

bool SubfloatFlow::preserveAddress(Varnode *vn,int4 bitSize,int4 lsbOffset) const

{
  return vn->isInput();		// Only try to preserve address for input varnodes
}

/// The interpretation that the root Varnode contains a logical value with
/// smaller precision is pushed through the data-flow.  If the interpretation is
/// inconsistent, \b false is returned.  Otherwise a transform is constructed that
/// makes the smaller precision the explicit size of Varnodes within the data-flow.
/// \return \b true if a transform consistent with the given precision can be built
bool SubfloatFlow::doTrace(void)

{
  if (format == (const FloatFormat *)0)
    return false;
  terminatorCount = 0;	// Have seen no terminators
  bool retval = true;
  while(!worklist.empty()) {
    if (!processNextWork()) {
      retval = false;
      break;
    }
  }

  clearVarnodeMarks();

  if (!retval) return false;
  if (terminatorCount == 0) return false;	// Must see at least 1 terminator
  return true;
}

/// \brief Find or build the placeholder objects for a Varnode that needs to be split into lanes
///
/// The Varnode is split based on the given subset of the lane description.
/// Constants can be split. Decide if the Varnode needs to go into the work list.
/// If the Varnode cannot be acceptably split, return null.
/// \param vn is the Varnode that needs to be split
/// \param numLanes is the number of lanes in the subset
/// \param skipLanes is the start (least significant) lane in the subset
/// \return the array of placeholders describing the split or null
TransformVar *LaneDivide::setReplacement(Varnode *vn,int4 numLanes,int4 skipLanes)

{
  if (vn->isMark())		// Already seen before
    return getSplit(vn, description, numLanes, skipLanes);

  if (vn->isConstant()) {
    return newSplit(vn,description, numLanes, skipLanes);
  }

  // Allow free varnodes to be split
//  if (vn->isFree())
//    return (TransformVar *)0;

  if (vn->isTypeLock())
    return (TransformVar *)0;

  vn->setMark();
  TransformVar *res = newSplit(vn, description, numLanes, skipLanes);
  if (!vn->isFree()) {
    workList.emplace_back();
    workList.back().lanes = res;
    workList.back().numLanes = numLanes;
    workList.back().skipLanes = skipLanes;
  }
  return res;
}

/// \brief Build unary op placeholders with the same opcode across a set of lanes
///
/// We assume the input and output placeholder variables have already been collected
/// \param opc is the desired opcode for the new op placeholders
/// \param op is the PcodeOp getting replaced
/// \param inVars is the array of input variables, 1 for each unary op
/// \param outVars is the array of output variables, 1 for each unary op
/// \param numLanes is the number of unary ops to create
void LaneDivide::buildUnaryOp(OpCode opc,PcodeOp *op,TransformVar *inVars,TransformVar *outVars,int4 numLanes)

{
  for(int4 i=0;i<numLanes;++i) {
    TransformOp *rop = newOpReplace(1, opc, op);
    opSetOutput(rop, outVars + i);
    opSetInput(rop,inVars + i,0);
  }
}

/// \brief Build binary op placeholders with the same opcode across a set of lanes
///
/// We assume the input and output placeholder variables have already been collected
/// \param opc is the desired opcode for the new op placeholders
/// \param op is the PcodeOp getting replaced
/// \param in0Vars is the array of input[0] variables, 1 for each binary op
/// \param in1Vars is the array of input[1] variables, 1 for each binar op
/// \param outVars is the array of output variables, 1 for each binary op
/// \param numLanes is the number of binary ops to create
void LaneDivide::buildBinaryOp(OpCode opc,PcodeOp *op,TransformVar *in0Vars,TransformVar *in1Vars,
			       TransformVar *outVars,int4 numLanes)
{
  for(int4 i=0;i<numLanes;++i) {
    TransformOp *rop = newOpReplace(2, opc, op);
    opSetOutput(rop, outVars + i);
    opSetInput(rop,in0Vars + i, 0);
    opSetInput(rop,in1Vars + i, 1);
  }
}

/// \brief Convert a CPUI_PIECE operation into copies between placeholders, given the output lanes
///
/// Model the given CPUI_PIECE either as either copies from preexisting Varnodes into the
/// output lanes, or as copies from placeholder variables into the output lanes.  Return \b false
/// if the operation cannot be modeled as natural copies between lanes.
/// \param op is the original CPUI_PIECE PcodeOp
/// \param outVars is the placeholder variables making up the lanes of the output
/// \param numLanes is the number of lanes in the output
/// \param skipLanes is the index of the least significant output lane within the global description
/// \return \b true if the CPUI_PIECE was modeled as natural lane copies
bool LaneDivide::buildPiece(PcodeOp *op,TransformVar *outVars,int4 numLanes,int4 skipLanes)

{
  int4 highLanes,highSkip;
  int4 lowLanes,lowSkip;
  Varnode *highVn = op->getIn(0);
  Varnode *lowVn = op->getIn(1);

  if (!description.restriction(numLanes,skipLanes,lowVn->getSize(),highVn->getSize(),highLanes,highSkip))
    return false;
  if (!description.restriction(numLanes,skipLanes,0,lowVn->getSize(),lowLanes,lowSkip))
    return false;
  if (highLanes == 1) {
    TransformVar *highRvn = getPreexistingVarnode(highVn);
    TransformOp *rop = newOpReplace(1, CPUI_COPY, op);
    opSetInput(rop,highRvn,0);
    opSetOutput(rop,outVars + (numLanes-1));
  }
  else {	// Multi-lane high
    TransformVar *highRvn = setReplacement(highVn, highLanes, highSkip);
    if (highRvn == (TransformVar *)0) return false;
    int4 outHighStart = numLanes - highLanes;
    for(int4 i=0;i<highLanes;++i) {
      TransformOp *rop = newOpReplace(1, CPUI_COPY, op);
      opSetInput(rop,highRvn+i,0);
      opSetOutput(rop,outVars + (outHighStart + i));
    }
  }
  if (lowLanes == 1) {
    TransformVar *lowRvn = getPreexistingVarnode(lowVn);
    TransformOp *rop = newOpReplace(1, CPUI_COPY, op);
    opSetInput(rop,lowRvn,0);
    opSetOutput(rop,outVars);
  }
  else {	// Multi-lane low
    TransformVar *lowRvn = setReplacement(lowVn, lowLanes, lowSkip);
    if (lowRvn == (TransformVar *)0) return false;
    for(int4 i=0;i<lowLanes;++i) {
      TransformOp *rop = newOpReplace(1, CPUI_COPY, op);
      opSetInput(rop,lowRvn+i,0);
      opSetOutput(rop,outVars + i);
    }
  }
  return true;
}

/// \brief Split a given CPUI_MULTIEQUAL operation into placeholders given the output lanes
///
/// Model the single given CPUI_MULTIEQUAL as a sequence of smaller MULTIEQUALs on
/// each individual lane. Return \b false if the operation cannot be modeled as naturally.
/// \param op is the original CPUI_MULTIEQUAL PcodeOp
/// \param outVars is the placeholder variables making up the lanes of the output
/// \param numLanes is the number of lanes in the output
/// \param skipLanes is the index of the least significant output lane within the global description
/// \return \b true if the operation was fully modeled
bool LaneDivide::buildMultiequal(PcodeOp *op,TransformVar *outVars,int4 numLanes,int4 skipLanes)

{
  vector<TransformVar *> inVarSets;
  int4 numInput = op->numInput();
  for(int4 i=0;i<numInput;++i) {
    TransformVar *inVn = setReplacement(op->getIn(i), numLanes, skipLanes);
    if (inVn == (TransformVar *)0) return false;
    inVarSets.push_back(inVn);
  }
  for(int4 i=0;i<numLanes;++i) {
    TransformOp *rop = newOpReplace(numInput, CPUI_MULTIEQUAL, op);
    opSetOutput(rop, outVars + i);
    for(int4 j=0;j<numInput;++j)
      opSetInput(rop, inVarSets[j] + i, j);
  }
  return true;
}

/// \brief Split a given CPUI_STORE operation into a sequence of STOREs of individual lanes
///
/// A new pointer is constructed for each individual lane into a temporary, then a
/// STORE is created using the pointer that stores an individual lane.
/// \param op is the given CPUI_STORE PcodeOp
/// \param numLanes is the number of lanes the STORE is split into
/// \param skipLanes is the starting lane (within the global description) of the value being stored
/// \return \b true if the CPUI_STORE was successfully modeled on lanes
bool LaneDivide::buildStore(PcodeOp *op,int4 numLanes,int4 skipLanes)

{
  TransformVar *inVars = setReplacement(op->getIn(2), numLanes, skipLanes);
  if (inVars == (TransformVar *)0) return false;
  uintb spaceConst = op->getIn(0)->getOffset();
  int4 spaceConstSize = op->getIn(0)->getSize();
  AddrSpace *spc = Address::getSpaceFromConst(op->getIn(0)->getAddr());	// Address space being stored to
  Varnode *origPtr = op->getIn(1);
  if (origPtr->isFree()) {
    if (!origPtr->isConstant()) return false;
  }
  TransformVar *basePtr = getPreexistingVarnode(origPtr);
  int4 ptrSize = origPtr->getSize();
  Varnode *valueVn = op->getIn(2);
  for(int4 i=0;i<numLanes;++i) {
    TransformOp *ropStore = newOpReplace(3, CPUI_STORE, op);
    int4 bytePos = description.getPosition(skipLanes + i);
    int4 sz = description.getSize(skipLanes + i);
    if (spc->isBigEndian())
      bytePos = valueVn->getSize() - (bytePos + sz);	// Convert position to address order

    // Construct the pointer
    TransformVar *ptrVn;
    if (bytePos == 0)
      ptrVn = basePtr;
    else {
      ptrVn = newUnique(ptrSize);
      TransformOp *addOp = newOp(2, CPUI_INT_ADD, ropStore);
      opSetOutput(addOp,ptrVn);
      opSetInput(addOp,basePtr,0);
      opSetInput(addOp,newConstant(ptrSize, 0, bytePos), 1);
    }

    opSetInput(ropStore,newConstant(spaceConstSize,0,spaceConst),0);
    opSetInput(ropStore,ptrVn,1);
    opSetInput(ropStore,inVars+i,2);
  }
  return true;
}

/// \brief Split a given CPUI_LOAD operation into a sequence of LOADs of individual lanes
///
/// A new pointer is constructed for each individual lane into a temporary, then a
/// LOAD is created using the pointer that loads an individual lane.
/// \param op is the given CPUI_LOAD PcodeOp
/// \param outVars is the output placeholders for the LOAD
/// \param numLanes is the number of lanes the LOAD is split into
/// \param skipLanes is the starting lane (within the global description) of the value being loaded
/// \return \b true if the CPUI_LOAD was successfully modeled on lanes
bool LaneDivide::buildLoad(PcodeOp *op,TransformVar *outVars,int4 numLanes,int4 skipLanes)

{
  uintb spaceConst = op->getIn(0)->getOffset();
  int4 spaceConstSize = op->getIn(0)->getSize();
  AddrSpace *spc = Address::getSpaceFromConst(op->getIn(0)->getAddr());	// Address space being stored to
  Varnode *origPtr = op->getIn(1);
  if (origPtr->isFree()) {
    if (!origPtr->isConstant()) return false;
  }
  TransformVar *basePtr = getPreexistingVarnode(origPtr);
  int4 ptrSize = origPtr->getSize();
  int4 outSize = op->getOut()->getSize();
  for(int4 i=0;i<numLanes;++i) {
    TransformOp *ropLoad = newOpReplace(2, CPUI_LOAD, op);
    int4 bytePos = description.getPosition(skipLanes + i);
    int4 sz = description.getSize(skipLanes + i);
    if (spc->isBigEndian())
      bytePos = outSize - (bytePos + sz);	// Convert position to address order

    // Construct the pointer
    TransformVar *ptrVn;
    if (bytePos == 0)
      ptrVn = basePtr;
    else {
      ptrVn = newUnique(ptrSize);
      TransformOp *addOp = newOp(2, CPUI_INT_ADD, ropLoad);
      opSetOutput(addOp,ptrVn);
      opSetInput(addOp,basePtr,0);
      opSetInput(addOp,newConstant(ptrSize, 0, bytePos), 1);
    }

    opSetInput(ropLoad,newConstant(spaceConstSize,0,spaceConst),0);
    opSetInput(ropLoad,ptrVn,1);
    opSetOutput(ropLoad,outVars+i);
  }
  return true;
}

/// \brief Check that a CPUI_INT_RIGHT respects the lanes then generate lane placeholders
///
/// For the given lane scheme, check that the RIGHT shift is copying whole lanes to each other.
/// If so, generate the placeholder COPYs that model the shift.
/// \param op is the given CPUI_INT_RIGHT PcodeOp
/// \param outVars is the output placeholders for the RIGHT shift
/// \param numLanes is the number of lanes the shift is split into
/// \param skipLanes is the starting lane (within the global description) of the value being loaded
/// \return \b true if the CPUI_INT_RIGHT was successfully modeled on lanes
bool LaneDivide::buildRightShift(PcodeOp *op,TransformVar *outVars,int4 numLanes,int4 skipLanes)

{
  if (!op->getIn(1)->isConstant()) return false;
  int4 shiftSize = (int4)op->getIn(1)->getOffset();
  if ((shiftSize & 7) != 0) return false;		// Not a multiple of 8
  shiftSize /= 8;
  int4 startPos = shiftSize + description.getPosition(skipLanes);
  int4 startLane = description.getBoundary(startPos);
  if (startLane < 0) return false;		// Shift does not end on a lane boundary
  int4 srcLane = startLane;
  int4 destLane = skipLanes;
  while(srcLane - skipLanes < numLanes) {
    if (description.getSize(srcLane) != description.getSize(destLane)) return false;
    srcLane += 1;
    destLane += 1;
  }
  TransformVar *inVars = setReplacement(op->getIn(0), numLanes, skipLanes);
  if (inVars == (TransformVar *)0) return false;
  buildUnaryOp(CPUI_COPY, op, inVars + (startLane - skipLanes), outVars, numLanes - (startLane - skipLanes));
  for(int4 zeroLane=numLanes - (startLane - skipLanes);zeroLane < numLanes;++zeroLane) {
    TransformOp *rop = newOpReplace(1, CPUI_COPY, op);
    opSetOutput(rop,outVars + zeroLane);
    opSetInput(rop,newConstant(description.getSize(zeroLane), 0, 0),0);
  }
  return true;
}

/// \brief Push the logical lanes forward through any PcodeOp reading the given variable
///
/// Determine if the logical lanes can be pushed forward naturally, and create placeholder
/// variables and ops representing the logical data-flow.  Update the worklist with any
/// new Varnodes that the lanes get pushed into.
/// \param rvn is the placeholder variable to push forward from
/// \param numLanes is the number of lanes represented by the placeholder variable
/// \param skipLanes is the index of the starting lane within the global description of the placeholder variable
/// \return \b true if the lanes can be naturally pushed forward
bool LaneDivide::traceForward(TransformVar *rvn,int4 numLanes,int4 skipLanes)

{
  Varnode *origvn = rvn->getOriginal();
  list<PcodeOp *>::const_iterator iter,enditer;
  iter = origvn->beginDescend();
  enditer = origvn->endDescend();
  while(iter != enditer) {
    PcodeOp *op = *iter++;
    Varnode *outvn = op->getOut();
    if ((outvn!=(Varnode *)0)&&(outvn->isMark()))
      continue;
    switch(op->code()) {
      case CPUI_SUBPIECE:
      {
	int4 bytePos = (int4)op->getIn(1)->getOffset();
	int4 outLanes,outSkip;
	if (!description.restriction(numLanes, skipLanes, bytePos, outvn->getSize(), outLanes, outSkip)) {
	  if (allowSubpieceTerminator) {
	    int4 laneIndex = description.getBoundary(bytePos);
	    if (laneIndex < 0 || laneIndex >= description.getNumLanes())	// Does piece start on lane boundary?
	      return false;
	    if (description.getSize(laneIndex) <= outvn->getSize())		// Is the piece smaller than a lane?
	      return false;
	    // Treat SUBPIECE as terminating
	    TransformOp *rop = newPreexistingOp(2, CPUI_SUBPIECE, op);
	    opSetInput(rop, rvn + (laneIndex - skipLanes), 0);
	    opSetInput(rop, newConstant(4, 0, 0), 1);
	    break;
	  }
	  return false;
	}
	if (outLanes == 1) {
	  TransformOp *rop = newPreexistingOp(1, CPUI_COPY, op);
	  opSetInput(rop,rvn + (outSkip-skipLanes), 0);
	}
	else {
	  TransformVar *outRvn = setReplacement(outvn,outLanes,outSkip);
	  if (outRvn == (TransformVar *)0) return false;
	  // Don't create the placeholder ops, let traceBackward make them
	}
	break;
      }
      case CPUI_PIECE:
      {
	int4 outLanes,outSkip;
	int4 bytePos = (op->getIn(0) == origvn) ? op->getIn(1)->getSize() : 0;
	if (!description.extension(numLanes, skipLanes, bytePos, outvn->getSize(), outLanes, outSkip))
	  return false;
	TransformVar *outRvn = setReplacement(outvn,outLanes,outSkip);
	if (outRvn == (TransformVar *)0) return false;
	// Don't create the placeholder ops, let traceBackward make them
	break;
      }
      case CPUI_COPY:
      case CPUI_INT_NEGATE:
      case CPUI_INT_AND:
      case CPUI_INT_OR:
      case CPUI_INT_XOR:
      case CPUI_MULTIEQUAL:
      {
	TransformVar *outRvn = setReplacement(outvn,numLanes,skipLanes);
	if (outRvn == (TransformVar *)0) return false;
	// Don't create the placeholder ops, let traceBackward make them
	break;
      }
      case CPUI_INT_RIGHT:
      {
	if (!op->getIn(1)->isConstant()) return false;	// Trace must come through op->getIn(0)
	TransformVar *outRvn = setReplacement(outvn, numLanes, skipLanes);
	if (outRvn == (TransformVar *)0) return false;
	// Don't create the placeholder ops, let traceBackward make them
	break;
      }
      case CPUI_STORE:
	if (op->getIn(2) != origvn) return false;	// Can only propagate through value being stored
	if (!buildStore(op,numLanes,skipLanes))
	  return false;
	break;
      default:
	return false;
    }
  }
  return true;
}

/// \brief Pull the logical lanes back through the defining PcodeOp of the given variable
///
/// Determine if the logical lanes can be pulled back naturally, and create placeholder
/// variables and ops representing the logical data-flow.  Update the worklist with any
/// new Varnodes that the lanes get pulled back into.
/// \param rvn is the placeholder variable to pull back
/// \param numLanes is the number of lanes represented by the placeholder variable
/// \param skipLanes is the index of the starting lane within the global description of the placeholder variable
/// \return \b true if the lanes can be naturally pulled back
bool LaneDivide::traceBackward(TransformVar *rvn,int4 numLanes,int4 skipLanes)

{
  PcodeOp *op = rvn->getOriginal()->getDef();
  if (op == (PcodeOp *)0) return true; // If vn is input

  switch(op->code()) {
    case CPUI_INT_NEGATE:
    case CPUI_COPY:
    {
      TransformVar *inVars = setReplacement(op->getIn(0),numLanes,skipLanes);
      if (inVars == (TransformVar *)0) return false;
      buildUnaryOp(op->code(), op, inVars, rvn, numLanes);
      break;
    }
    case CPUI_INT_AND:
    case CPUI_INT_OR:
    case CPUI_INT_XOR:
    {
      TransformVar *in0Vars = setReplacement(op->getIn(0),numLanes,skipLanes);
      if (in0Vars == (TransformVar *)0) return false;
      TransformVar *in1Vars = setReplacement(op->getIn(1),numLanes,skipLanes);
      if (in1Vars == (TransformVar *)0) return false;
      buildBinaryOp(op->code(),op,in0Vars,in1Vars,rvn,numLanes);
      break;
    }
    case CPUI_MULTIEQUAL:
      if (!buildMultiequal(op, rvn, numLanes, skipLanes))
	return false;
      break;
    case CPUI_SUBPIECE:
    {
      Varnode *inVn = op->getIn(0);
      int4 bytePos = (int4)op->getIn(1)->getOffset();
      int4 inLanes,inSkip;
      if (!description.extension(numLanes, skipLanes, bytePos, inVn->getSize(), inLanes, inSkip))
	return false;
      TransformVar *inVars = setReplacement(inVn,inLanes,inSkip);
      if (inVars == (TransformVar *)0) return false;
      buildUnaryOp(CPUI_COPY,op,inVars + (skipLanes - inSkip), rvn, numLanes);
      break;
    }
    case CPUI_PIECE:
      if (!buildPiece(op, rvn, numLanes, skipLanes))
	return false;
      break;
    case CPUI_LOAD:
      if (!buildLoad(op, rvn, numLanes, skipLanes))
	return false;
      break;
    case CPUI_INT_RIGHT:
      if (!buildRightShift(op, rvn, numLanes, skipLanes))
	return false;
      break;
    default:
      return false;
  }
  return true;
}

/// \return \b true if the lane split for the top Varnode on the work list is propagated through local operators
bool LaneDivide::processNextWork(void)

{
  TransformVar *rvn = workList.back().lanes;
  int4 numLanes = workList.back().numLanes;
  int4 skipLanes = workList.back().skipLanes;

  workList.pop_back();

  if (!traceBackward(rvn,numLanes,skipLanes)) return false;
  return traceForward(rvn,numLanes,skipLanes);
}

/// \param f is the function being transformed
/// \param root is the root Varnode to start tracing lanes from
/// \param desc is a description of the lanes on the root Varnode
/// \param allowDowncast is \b true if we all SUBPIECE to be treated as terminating
LaneDivide::LaneDivide(Funcdata *f,Varnode *root,const LaneDescription &desc,bool allowDowncast)
  : TransformManager(f), description(desc)
{
  allowSubpieceTerminator = allowDowncast;
  setReplacement(root, desc.getNumLanes(), 0);
}

/// Push the lanes around from the root, setting up the explicit transforms as we go.
/// If at any point, the lanes cannot be naturally pushed, return \b false.
/// \return \b true if a full transform has been constructed that can split into explicit lanes
bool LaneDivide::doTrace(void)

{
  if (workList.empty())
    return false;		// Nothing to do
  bool retval = true;
  while(!workList.empty()) {	// Process the work list until its done
    if (!processNextWork()) {
      retval = false;
      break;
    }
  }

  clearVarnodeMarks();
  if (!retval) return false;
  return true;
}