Move sparc-specific livevar code into lib/Target/Sparc

llvm-svn: 10733

6 files changed, 688 insertions, 1 deletions

diff --git a/llvm/lib/Target/Sparc/LiveVar/BBLiveVar.cpp b/llvm/lib/Target/Sparc/LiveVar/BBLiveVar.cpp
new file mode 100644
index 00000000000..f54b42ab12a
--- /dev/null
+++ b/llvm/lib/Target/Sparc/LiveVar/BBLiveVar.cpp
@@ -0,0 +1,230 @@
+//===-- BBLiveVar.cpp - Live Variable Analysis for a BasicBlock -----------===//
+// 
+//                     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 is a wrapper class for BasicBlock which is used by live var analysis.
+//
+//===----------------------------------------------------------------------===//
+
+#include "BBLiveVar.h"
+#include "llvm/CodeGen/FunctionLiveVarInfo.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/Support/CFG.h"
+#include "Support/SetOperations.h"
+#include "../SparcInternals.h"
+
+namespace llvm {
+
+BBLiveVar::BBLiveVar(const BasicBlock &bb, MachineBasicBlock &mbb, unsigned id)
+  : BB(bb), MBB(mbb), POID(id) {
+  InSetChanged = OutSetChanged = false;
+
+  calcDefUseSets();
+}
+
+//-----------------------------------------------------------------------------
+// calculates def and use sets for each BB
+// There are two passes over operands of a machine instruction. This is
+// because, we can have instructions like V = V + 1, since we no longer
+// assume single definition.
+//-----------------------------------------------------------------------------
+
+void BBLiveVar::calcDefUseSets() {
+  // iterate over all the machine instructions in BB
+  for (MachineBasicBlock::const_reverse_iterator MII = MBB.rbegin(),
+         MIE = MBB.rend(); MII != MIE; ++MII) {
+    const MachineInstr *MI = *MII;
+    
+    if (DEBUG_LV >= LV_DEBUG_Verbose) {
+      std::cerr << " *Iterating over machine instr ";
+      MI->dump();
+      std::cerr << "\n";
+    }
+
+    // iterate over  MI operands to find defs
+    for (MachineInstr::const_val_op_iterator OpI = MI->begin(), OpE = MI->end();
+         OpI != OpE; ++OpI)
+      if (OpI.isDef()) // add to Defs if this operand is a def
+	addDef(*OpI);
+
+    // do for implicit operands as well
+    for (unsigned i = 0; i < MI->getNumImplicitRefs(); ++i)
+      if (MI->getImplicitOp(i).isDef())
+	addDef(MI->getImplicitRef(i));
+    
+    // iterate over MI operands to find uses
+    for (MachineInstr::const_val_op_iterator OpI = MI->begin(), OpE = MI->end();
+         OpI != OpE; ++OpI) {
+      const Value *Op = *OpI;
+
+      if (isa<BasicBlock>(Op))
+	continue;             // don't process labels
+
+      if (OpI.isUse()) { // add to Uses only if this operand is a use
+        //
+        // *** WARNING: The following code for handling dummy PHI machine
+        //     instructions is untested.  The previous code was broken and I
+        //     fixed it, but it turned out to be unused as long as Phi
+        //     elimination is performed during instruction selection.
+        // 
+        // Put Phi operands in UseSet for the incoming edge, not node.
+        // They must not "hide" later defs, and must be handled specially
+        // during set propagation over the CFG.
+	if (MI->getOpCode() == V9::PHI) {         // for a phi node
+          const Value *ArgVal = Op;
+	  const BasicBlock *PredBB = cast<BasicBlock>(*++OpI); // next ptr is BB
+	  
+	  PredToEdgeInSetMap[PredBB].insert(ArgVal); 
+	  
+	  if (DEBUG_LV >= LV_DEBUG_Verbose)
+	    std::cerr << "   - phi operand " << RAV(ArgVal) << " came from BB "
+                      << RAV(PredBB) << "\n";
+	} // if( IsPhi )
+        else {
+          // It is not a Phi use: add to regular use set and remove later defs.
+          addUse(Op);
+        }
+      } // if a use
+    } // for all operands
+
+    // do for implicit operands as well
+    for (unsigned i = 0; i < MI->getNumImplicitRefs(); ++i) {
+      assert(MI->getOpCode() != V9::PHI && "Phi cannot have implicit operands");
+      const Value *Op = MI->getImplicitRef(i);
+
+      if (Op->getType() == Type::LabelTy)             // don't process labels
+	continue;
+
+      if (MI->getImplicitOp(i).isUse())
+	addUse(Op);
+    }
+  } // for all machine instructions
+} 
+
+
+	
+//-----------------------------------------------------------------------------
+// To add an operand which is a def
+//-----------------------------------------------------------------------------
+void BBLiveVar::addDef(const Value *Op) {
+  DefSet.insert(Op);     // operand is a def - so add to def set
+  InSet.erase(Op);       // this definition kills any later uses
+  InSetChanged = true; 
+
+  if (DEBUG_LV >= LV_DEBUG_Verbose) std::cerr << "  +Def: " << RAV(Op) << "\n";
+}
+
+
+//-----------------------------------------------------------------------------
+// To add an operand which is a use
+//-----------------------------------------------------------------------------
+void  BBLiveVar::addUse(const Value *Op) {
+  InSet.insert(Op);   // An operand is a use - so add to use set
+  DefSet.erase(Op);   // remove if there is a def below this use
+  InSetChanged = true; 
+
+  if (DEBUG_LV >= LV_DEBUG_Verbose) std::cerr << "   Use: " << RAV(Op) << "\n";
+}
+
+
+//-----------------------------------------------------------------------------
+// Applies the transfer function to a basic block to produce the InSet using
+// the OutSet. 
+//-----------------------------------------------------------------------------
+
+bool BBLiveVar::applyTransferFunc() {
+  // IMPORTANT: caller should check whether the OutSet changed 
+  //           (else no point in calling)
+
+  ValueSet OutMinusDef = set_difference(OutSet, DefSet);
+  InSetChanged = set_union(InSet, OutMinusDef);
+ 
+  OutSetChanged = false;      // no change to OutSet since transf func applied
+  return InSetChanged;
+}
+
+
+//-----------------------------------------------------------------------------
+// calculates Out set using In sets of the successors
+//-----------------------------------------------------------------------------
+
+bool BBLiveVar::setPropagate(ValueSet *OutSet, const ValueSet *InSet, 
+                             const BasicBlock *PredBB) {
+  bool Changed = false;
+  
+  // merge all members of InSet into OutSet of the predecessor
+  for (ValueSet::const_iterator InIt = InSet->begin(), InE = InSet->end();
+       InIt != InE; ++InIt)
+    if ((OutSet->insert(*InIt)).second)
+      Changed = true;
+  
+  // 
+  //**** WARNING: The following code for handling dummy PHI machine
+  //     instructions is untested.  See explanation above.
+  // 
+  // then merge all members of the EdgeInSet for the predecessor into the OutSet
+  const ValueSet& EdgeInSet = PredToEdgeInSetMap[PredBB];
+  for (ValueSet::const_iterator InIt = EdgeInSet.begin(), InE = EdgeInSet.end();
+       InIt != InE; ++InIt)
+    if ((OutSet->insert(*InIt)).second)
+      Changed = true;
+  // 
+  //****
+  
+  return Changed;
+} 
+
+
+//-----------------------------------------------------------------------------
+// propagates in set to OutSets of PREDECESSORs
+//-----------------------------------------------------------------------------
+
+bool BBLiveVar::applyFlowFunc(hash_map<const BasicBlock*,
+                                       BBLiveVar*> &BBLiveVarInfo) {
+  // IMPORTANT: caller should check whether inset changed 
+  //            (else no point in calling)
+  
+  // If this BB changed any OutSets of preds whose POID is lower, than we need
+  // another iteration...
+  //
+  bool needAnotherIt = false;  
+
+  for (pred_const_iterator PI = pred_begin(&BB), PE = pred_end(&BB);
+       PI != PE ; ++PI) {
+    BBLiveVar *PredLVBB = BBLiveVarInfo[*PI];
+
+    // do set union
+    if (setPropagate(&PredLVBB->OutSet, &InSet, *PI)) {  
+      PredLVBB->OutSetChanged = true;
+
+      // if the predec POID is lower than mine
+      if (PredLVBB->getPOId() <= POID)
+	needAnotherIt = true;   
+    }
+  }  // for
+
+  return needAnotherIt;
+}
+
+
+
+// ----------------- Methods For Debugging (Printing) -----------------
+
+void BBLiveVar::printAllSets() const {
+  std::cerr << "  Defs: "; printSet(DefSet);  std::cerr << "\n";
+  std::cerr << "  In: ";  printSet(InSet);  std::cerr << "\n";
+  std::cerr << "  Out: "; printSet(OutSet);  std::cerr << "\n";
+}
+
+void BBLiveVar::printInOutSets() const {
+  std::cerr << "  In: ";   printSet(InSet);  std::cerr << "\n";
+  std::cerr << "  Out: ";  printSet(OutSet);  std::cerr << "\n";
+}
+
+} // End llvm namespace
diff --git a/llvm/lib/Target/Sparc/LiveVar/BBLiveVar.h b/llvm/lib/Target/Sparc/LiveVar/BBLiveVar.h
new file mode 100644
index 00000000000..781143a93df
--- /dev/null
+++ b/llvm/lib/Target/Sparc/LiveVar/BBLiveVar.h
@@ -0,0 +1,90 @@
+//===-- BBLiveVar.h - Live Variable Analysis for a BasicBlock ---*- C++ -*-===//
+// 
+//                     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 is a BasicBlock annotation class that is used by live var analysis to
+// hold data flow information for a basic block.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LIVE_VAR_BB_H
+#define LIVE_VAR_BB_H
+
+#include "llvm/CodeGen/ValueSet.h"
+#include "Support/hash_map"
+
+namespace llvm {
+
+class BasicBlock;
+class Value;
+class MachineBasicBlock;
+
+enum LiveVarDebugLevel_t {
+  LV_DEBUG_None,
+  LV_DEBUG_Normal,
+  LV_DEBUG_Instr,
+  LV_DEBUG_Verbose
+};
+
+extern LiveVarDebugLevel_t DEBUG_LV;
+
+class BBLiveVar {
+  const BasicBlock &BB;         // pointer to BasicBlock
+  MachineBasicBlock &MBB;       // Pointer to MachineBasicBlock
+  unsigned POID;                // Post-Order ID
+
+  ValueSet DefSet;           // Def set (with no preceding uses) for LV analysis
+  ValueSet InSet, OutSet;       // In & Out for LV analysis
+  bool InSetChanged, OutSetChanged;   // set if the InSet/OutSet is modified
+
+                                // map that contains PredBB -> Phi arguments
+                                // coming in on that edge.  such uses have to be
+                                // treated differently from ordinary uses.
+  hash_map<const BasicBlock *, ValueSet> PredToEdgeInSetMap;
+  
+  // method to propagate an InSet to OutSet of a predecessor
+  bool setPropagate(ValueSet *OutSetOfPred, 
+                    const ValueSet *InSetOfThisBB,
+                    const BasicBlock *PredBB);
+
+  // To add an operand which is a def
+  void addDef(const Value *Op); 
+
+  // To add an operand which is a use
+  void addUse(const Value *Op);
+
+  void calcDefUseSets();         // calculates the Def & Use sets for this BB
+public:
+
+  BBLiveVar(const BasicBlock &BB, MachineBasicBlock &MBB, unsigned POID);
+
+  inline bool isInSetChanged() const  { return InSetChanged; }    
+  inline bool isOutSetChanged() const { return OutSetChanged; }
+
+  MachineBasicBlock &getMachineBasicBlock() const { return MBB; }
+
+  inline unsigned getPOId() const { return POID; }
+
+  bool applyTransferFunc();      // calcultes the In in terms of Out 
+
+  // calculates Out set using In sets of the predecessors
+  bool applyFlowFunc(hash_map<const BasicBlock*, BBLiveVar*> &BBLiveVarInfo);
+
+  inline const ValueSet &getOutSet() const { return OutSet; }
+  inline       ValueSet &getOutSet()       { return OutSet; }
+
+  inline const ValueSet  &getInSet() const { return InSet; }
+  inline       ValueSet  &getInSet()       { return InSet; }
+
+  void printAllSets() const;      // for printing Def/In/Out sets
+  void printInOutSets() const;    // for printing In/Out sets
+};
+
+} // End llvm namespace
+
+#endif
diff --git a/llvm/lib/Target/Sparc/LiveVar/FunctionLiveVarInfo.cpp b/llvm/lib/Target/Sparc/LiveVar/FunctionLiveVarInfo.cpp
new file mode 100644
index 00000000000..e342760f723
--- /dev/null
+++ b/llvm/lib/Target/Sparc/LiveVar/FunctionLiveVarInfo.cpp
@@ -0,0 +1,322 @@
+//===-- FunctionLiveVarInfo.cpp - Live Variable Analysis for a Function ---===//
+// 
+//                     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 is the interface to function level live variable information that is
+// provided by live variable analysis.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/FunctionLiveVarInfo.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Support/CFG.h"
+#include "Support/PostOrderIterator.h"
+#include "Support/SetOperations.h"
+#include "Support/CommandLine.h"
+#include "BBLiveVar.h"
+
+namespace llvm {
+
+static RegisterAnalysis<FunctionLiveVarInfo>
+X("livevar", "Live Variable Analysis");
+
+LiveVarDebugLevel_t DEBUG_LV;
+
+static cl::opt<LiveVarDebugLevel_t, true>
+DEBUG_LV_opt("dlivevar", cl::Hidden, cl::location(DEBUG_LV),
+             cl::desc("enable live-variable debugging information"),
+             cl::values(
+clEnumValN(LV_DEBUG_None   , "n", "disable debug output"),
+clEnumValN(LV_DEBUG_Normal , "y", "enable debug output"),
+clEnumValN(LV_DEBUG_Instr,   "i", "print live-var sets before/after "
+           "every machine instrn"),
+clEnumValN(LV_DEBUG_Verbose, "v", "print def, use sets for every instrn also"),
+                        0));
+
+
+
+//-----------------------------------------------------------------------------
+// Accessor Functions
+//-----------------------------------------------------------------------------
+
+// gets OutSet of a BB
+const ValueSet &FunctionLiveVarInfo::getOutSetOfBB(const BasicBlock *BB) const {
+  return BBLiveVarInfo.find(BB)->second->getOutSet();
+}
+      ValueSet &FunctionLiveVarInfo::getOutSetOfBB(const BasicBlock *BB)       {
+  return BBLiveVarInfo[BB]->getOutSet();
+}
+
+// gets InSet of a BB
+const ValueSet &FunctionLiveVarInfo::getInSetOfBB(const BasicBlock *BB) const {
+  return BBLiveVarInfo.find(BB)->second->getInSet();
+}
+ValueSet &FunctionLiveVarInfo::getInSetOfBB(const BasicBlock *BB) {
+  return BBLiveVarInfo[BB]->getInSet();
+}
+
+
+//-----------------------------------------------------------------------------
+// Performs live var analysis for a function
+//-----------------------------------------------------------------------------
+
+bool FunctionLiveVarInfo::runOnFunction(Function &F) {
+  M = &F;
+  if (DEBUG_LV) std::cerr << "Analysing live variables ...\n";
+
+  // create and initialize all the BBLiveVars of the CFG
+  constructBBs(M);
+
+  unsigned int iter=0;
+  while (doSingleBackwardPass(M, iter++))
+    ; // Iterate until we are done.
+  
+  if (DEBUG_LV) std::cerr << "Live Variable Analysis complete!\n";
+  return false;
+}
+
+
+//-----------------------------------------------------------------------------
+// constructs BBLiveVars and init Def and In sets
+//-----------------------------------------------------------------------------
+
+void FunctionLiveVarInfo::constructBBs(const Function *F) {
+  unsigned POId = 0;                // Reverse Depth-first Order ID
+  std::map<const BasicBlock*, unsigned> PONumbering;
+
+  for (po_iterator<const Function*> BBI = po_begin(M), BBE = po_end(M);
+      BBI != BBE; ++BBI)
+    PONumbering[*BBI] = POId++;
+
+  MachineFunction &MF = MachineFunction::get(F);
+  for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
+    const BasicBlock &BB = *I->getBasicBlock();        // get the current BB 
+    if (DEBUG_LV) std::cerr << " For BB " << RAV(BB) << ":\n";
+
+    BBLiveVar *LVBB;
+    std::map<const BasicBlock*, unsigned>::iterator POI = PONumbering.find(&BB);
+    if (POI != PONumbering.end()) {
+      // create a new BBLiveVar
+      LVBB = new BBLiveVar(BB, *I, POId);
+    } else {
+      // The PO iterator does not discover unreachable blocks, but the random
+      // iterator later may access these blocks.  We must make sure to
+      // initialize unreachable blocks as well.  However, LV info is not correct
+      // for those blocks (they are not analyzed)
+      //
+      LVBB = new BBLiveVar(BB, *I, ++POId);
+    }
+    BBLiveVarInfo[&BB] = LVBB;
+    
+    if (DEBUG_LV)
+      LVBB->printAllSets();
+  }
+}
+
+
+//-----------------------------------------------------------------------------
+// do one backward pass over the CFG (for iterative analysis)
+//-----------------------------------------------------------------------------
+
+bool FunctionLiveVarInfo::doSingleBackwardPass(const Function *M,
+                                               unsigned iter) {
+  if (DEBUG_LV) std::cerr << "\n After Backward Pass " << iter << "...\n";
+
+  bool NeedAnotherIteration = false;
+  for (po_iterator<const Function*> BBI = po_begin(M), BBE = po_end(M);
+       BBI != BBE; ++BBI) {
+    BBLiveVar *LVBB = BBLiveVarInfo[*BBI];
+    assert(LVBB && "BasicBlock information not set for block!");
+
+    if (DEBUG_LV) std::cerr << " For BB " << (*BBI)->getName() << ":\n";
+
+    // InSets are initialized to "GenSet". Recompute only if OutSet changed.
+    if(LVBB->isOutSetChanged()) 
+      LVBB->applyTransferFunc();        // apply the Tran Func to calc InSet
+    
+    // OutSets are initialized to EMPTY.  Recompute on first iter or if InSet
+    // changed.
+    if (iter == 0 || LVBB->isInSetChanged())        // to calc Outsets of preds
+      NeedAnotherIteration |= LVBB->applyFlowFunc(BBLiveVarInfo);
+    
+    if (DEBUG_LV) LVBB->printInOutSets();
+  }
+
+  // true if we need to reiterate over the CFG
+  return NeedAnotherIteration;         
+}
+
+
+void FunctionLiveVarInfo::releaseMemory() {
+  // First remove all BBLiveVars created in constructBBs().
+  if (M) {
+    for (Function::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
+      delete BBLiveVarInfo[I];
+    BBLiveVarInfo.clear();
+  }
+  M = 0;
+
+  // Then delete all objects of type ValueSet created in calcLiveVarSetsForBB
+  // and entered into MInst2LVSetBI and MInst2LVSetAI (these are caches
+  // to return ValueSet's before/after a machine instruction quickly).
+  // We do not need to free up ValueSets in MInst2LVSetAI because it holds
+  // pointers to the same sets as in MInst2LVSetBI (for all instructions
+  // except the last one in a BB) or in BBLiveVar (for the last instruction).
+  //
+  for (hash_map<const MachineInstr*, ValueSet*>::iterator
+         MI = MInst2LVSetBI.begin(),
+         ME = MInst2LVSetBI.end(); MI != ME; ++MI)
+    delete MI->second;           // delete all ValueSets in  MInst2LVSetBI
+
+  MInst2LVSetBI.clear();
+  MInst2LVSetAI.clear();
+}
+
+
+
+
+//-----------------------------------------------------------------------------
+// Following functions will give the LiveVar info for any machine instr in
+// a function. It should be called after a call to analyze().
+//
+// These functions calculate live var info for all the machine instrs in a 
+// BB when LVInfo for one inst is requested. Hence, this function is useful 
+// when live var info is required for many (or all) instructions in a basic 
+// block. Also, the arguments to this function does not require specific 
+// iterators.
+//-----------------------------------------------------------------------------
+
+//-----------------------------------------------------------------------------
+// Gives live variable information before a machine instruction
+//-----------------------------------------------------------------------------
+
+const ValueSet &
+FunctionLiveVarInfo::getLiveVarSetBeforeMInst(const MachineInstr *MI,
+                                              const BasicBlock *BB) {
+  ValueSet* &LVSet = MInst2LVSetBI[MI]; // ref. to map entry
+  if (LVSet == NULL && BB != NULL) {    // if not found and BB provided
+    calcLiveVarSetsForBB(BB);           // calc LVSet for all instrs in BB
+    assert(LVSet != NULL);
+  }
+  return *LVSet;
+}
+
+
+//-----------------------------------------------------------------------------
+// Gives live variable information after a machine instruction
+//-----------------------------------------------------------------------------
+
+const ValueSet & 
+FunctionLiveVarInfo::getLiveVarSetAfterMInst(const MachineInstr *MI,
+                                             const BasicBlock *BB) {
+
+  ValueSet* &LVSet = MInst2LVSetAI[MI]; // ref. to map entry
+  if (LVSet == NULL && BB != NULL) {    // if not found and BB provided 
+    calcLiveVarSetsForBB(BB);           // calc LVSet for all instrs in BB
+    assert(LVSet != NULL);
+  }
+  return *LVSet;
+}
+
+// This function applies a machine instr to a live var set (accepts OutSet) and
+// makes necessary changes to it (produces InSet). Note that two for loops are
+// used to first kill all defs and then to add all uses. This is because there
+// can be instructions like Val = Val + 1 since we allow multiple defs to a 
+// machine instruction operand.
+//
+static void applyTranferFuncForMInst(ValueSet &LVS, const MachineInstr *MInst) {
+  for (MachineInstr::const_val_op_iterator OpI = MInst->begin(),
+         OpE = MInst->end(); OpI != OpE; ++OpI) {
+    if (OpI.isDef())                          // kill if this operand is a def
+      LVS.erase(*OpI);                        // this definition kills any uses
+  }
+
+  // do for implicit operands as well
+  for (unsigned i=0; i < MInst->getNumImplicitRefs(); ++i) {
+    if (MInst->getImplicitOp(i).isDef())
+      LVS.erase(MInst->getImplicitRef(i));
+  }
+
+  for (MachineInstr::const_val_op_iterator OpI = MInst->begin(),
+         OpE = MInst->end(); OpI != OpE; ++OpI) {
+    if (!isa<BasicBlock>(*OpI))      // don't process labels
+      // add only if this operand is a use
+      if (OpI.isUse())
+        LVS.insert(*OpI);            // An operand is a use - so add to use set
+  }
+
+  // do for implicit operands as well
+  for (unsigned i = 0, e = MInst->getNumImplicitRefs(); i != e; ++i)
+    if (MInst->getImplicitOp(i).isUse())
+      LVS.insert(MInst->getImplicitRef(i));
+}
+
+//-----------------------------------------------------------------------------
+// This method calculates the live variable information for all the 
+// instructions in a basic block and enter the newly constructed live
+// variable sets into a the caches (MInst2LVSetAI, MInst2LVSetBI)
+//-----------------------------------------------------------------------------
+
+void FunctionLiveVarInfo::calcLiveVarSetsForBB(const BasicBlock *BB) {
+  BBLiveVar *BBLV = BBLiveVarInfo[BB];
+  assert(BBLV && "BBLiveVar annotation doesn't exist?");
+  const MachineBasicBlock &MIVec = BBLV->getMachineBasicBlock();
+  const MachineFunction &MF = MachineFunction::get(M);
+  const TargetMachine &TM = MF.getTarget();
+
+  if (DEBUG_LV >= LV_DEBUG_Instr)
+    std::cerr << "\n======For BB " << BB->getName()
+              << ": Live var sets for instructions======\n";
+  
+  ValueSet *SetAI = &getOutSetOfBB(BB);         // init SetAI with OutSet
+  ValueSet CurSet(*SetAI);                      // CurSet now contains OutSet
+
+  // iterate over all the machine instructions in BB
+  for (MachineBasicBlock::const_reverse_iterator MII = MIVec.rbegin(),
+         MIE = MIVec.rend(); MII != MIE; ++MII) {  
+    // MI is cur machine inst
+    const MachineInstr *MI = *MII;  
+
+    MInst2LVSetAI[MI] = SetAI;                 // record in After Inst map
+
+    applyTranferFuncForMInst(CurSet, MI);      // apply the transfer Func
+    ValueSet *NewSet = new ValueSet(CurSet);   // create a new set with a copy
+                                               // of the set after T/F
+    MInst2LVSetBI[MI] = NewSet;                // record in Before Inst map
+
+    // If the current machine instruction has delay slots, mark values
+    // used by this instruction as live before and after each delay slot
+    // instruction (After(MI) is the same as Before(MI+1) except for last MI).
+    if (unsigned DS = TM.getInstrInfo().getNumDelaySlots(MI->getOpCode())) {
+      MachineBasicBlock::const_iterator fwdMII = MII.base(); // ptr to *next* MI
+      for (unsigned i = 0; i < DS; ++i, ++fwdMII) {
+        assert(fwdMII != MIVec.end() && "Missing instruction in delay slot?");
+        MachineInstr* DelaySlotMI = *fwdMII;
+        if (! TM.getInstrInfo().isNop(DelaySlotMI->getOpCode())) {
+          set_union(*MInst2LVSetBI[DelaySlotMI], *NewSet);
+          if (i+1 == DS)
+            set_union(*MInst2LVSetAI[DelaySlotMI], *NewSet);
+        }
+      }
+    }
+
+    if (DEBUG_LV >= LV_DEBUG_Instr) {
+      std::cerr << "\nLive var sets before/after instruction " << *MI;
+      std::cerr << "  Before: ";   printSet(*NewSet);  std::cerr << "\n";
+      std::cerr << "  After : ";   printSet(*SetAI);   std::cerr << "\n";
+    }
+
+    // SetAI will be used in the next iteration
+    SetAI = NewSet;                 
+  }
+}
+
+} // End llvm namespace
diff --git a/llvm/lib/Target/Sparc/LiveVar/Makefile b/llvm/lib/Target/Sparc/LiveVar/Makefile
new file mode 100644
index 00000000000..90a664e56ce
--- /dev/null
+++ b/llvm/lib/Target/Sparc/LiveVar/Makefile
@@ -0,0 +1,14 @@
+##===- lib/Target/Sparc/LiveVar/Makefile -------------------*- Makefile -*-===##
+# 
+#                     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.
+# 
+##===----------------------------------------------------------------------===##
+
+LEVEL = ../../../..
+LIBRARYNAME = livevar
+
+include $(LEVEL)/Makefile.common
+
diff --git a/llvm/lib/Target/Sparc/LiveVar/ValueSet.cpp b/llvm/lib/Target/Sparc/LiveVar/ValueSet.cpp
new file mode 100644
index 00000000000..fd8289675a2
--- /dev/null
+++ b/llvm/lib/Target/Sparc/LiveVar/ValueSet.cpp
@@ -0,0 +1,31 @@
+// 
+//                     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.
+// 
+//===----------------------------------------------------------------------===//
+// FIXME: Eliminate this file.
+
+#include "llvm/CodeGen/ValueSet.h"
+#include "llvm/Value.h"
+#include <iostream>
+
+namespace llvm {
+
+std::ostream &operator<<(std::ostream &O, RAV V) { // func to print a Value 
+  const Value &v = V.V;
+  if (v.hasName())
+    return O << (void*)&v << "(" << v.getName() << ") ";
+  else if (isa<Constant>(v))
+    return O << (void*)&v << "(" << v << ") ";
+  else
+    return O << (void*)&v << " ";
+}
+
+void printSet(const ValueSet &S) {
+  for (ValueSet::const_iterator I = S.begin(), E = S.end(); I != E; ++I)
+    std::cerr << RAV(*I);
+}
+
+} // End llvm namespace
diff --git a/llvm/lib/Target/Sparc/Makefile b/llvm/lib/Target/Sparc/Makefile
index cf61657d753..619c9d02e7c 100644
--- a/llvm/lib/Target/Sparc/Makefile
+++ b/llvm/lib/Target/Sparc/Makefile
@@ -8,7 +8,7 @@
 ##===----------------------------------------------------------------------===##
 LEVEL = ../../..
 LIBRARYNAME = sparc
-DIRS = InstrSelection RegAlloc
+DIRS = InstrSelection RegAlloc LiveVar
 
 ExtraSource = Sparc.burm.cpp