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#include "llvm/Analysis/LiveVar/BBLiveVar.h"
#include "llvm/Analysis/LiveVar/MethodLiveVarInfo.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "../../Target/Sparc/SparcInternals.h" // TODO: FIXME!! Only for PHI defn
/********************* Implementation **************************************/
BBLiveVar::BBLiveVar( const BasicBlock *const baseBB, unsigned int RdfoId)
: BaseBB(baseBB), DefSet(), InSet(),
OutSet(), PhiArgMap() {
BaseBB = baseBB;
InSetChanged = OutSetChanged = false;
POId = RdfoId;
}
// caluculates 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()
{
// get the iterator for machine instructions
const MachineCodeForBasicBlock& MIVec = BaseBB->getMachineInstrVec();
MachineCodeForBasicBlock::const_reverse_iterator
MInstIterator = MIVec.rbegin();
// iterate over all the machine instructions in BB
for( ; MInstIterator != MIVec.rend(); ++MInstIterator) {
const MachineInstr * MInst = *MInstIterator; // MInst is the machine inst
assert(MInst);
if( DEBUG_LV > 1) { // debug msg
cout << " *Iterating over machine instr ";
MInst->dump();
cout << endl;
}
// iterate over MI operands to find defs
for( MachineInstr::val_op_const_iterator OpI(MInst); !OpI.done() ; ++OpI) {
if( OpI.isDef() ) // add to Defs only if this operand is a def
addDef( *OpI );
}
// do for implicit operands as well
for( unsigned i=0; i < MInst->getNumImplicitRefs(); ++i) {
if( MInst->implicitRefIsDefined(i) )
addDef( MInst->getImplicitRef(i) );
}
bool IsPhi = ( MInst->getOpCode() == PHI );
// iterate over MI operands to find uses
for(MachineInstr::val_op_const_iterator OpI(MInst); !OpI.done() ; ++OpI) {
const Value *Op = *OpI;
if ( ((Op)->getType())->isLabelType() )
continue; // don't process labels
if(! OpI.isDef() ) { // add to Defs only if this operand is a use
addUse( Op );
if( IsPhi ) { // for a phi node
// put args into the PhiArgMap (Val -> BB)
const Value * ArgVal = Op;
++OpI; // increment to point to BB of value
const Value * BBVal = *OpI;
assert( (BBVal)->getValueType() == Value::BasicBlockVal );
PhiArgMap[ ArgVal ] = (const BasicBlock *) (BBVal);
assert( PhiArgMap[ ArgVal ] );
if( DEBUG_LV > 1) { // debug msg of level 2
cout << " - phi operand ";
printValue( ArgVal );
cout << " came from BB ";
printValue( PhiArgMap[ ArgVal ]);
cout<<endl;
}
} // if( IsPhi )
} // if a use
} // for all operands
// do for implicit operands as well
for( unsigned i=0; i < MInst->getNumImplicitRefs(); ++i) {
assert( !IsPhi && "Phi cannot have implicit opeands");
const Value *Op = MInst->getImplicitRef(i);
if ( ((Op)->getType())->isLabelType() )
continue; // don't process labels
if( ! MInst->implicitRefIsDefined(i) )
addUse( Op );
}
} // for all machine instructions
}
// To add an operand wichi is a def
void BBLiveVar::addDef(const Value *Op)
{
DefSet.add( Op ); // operand is a def - so add to def set
InSet.remove( Op); // this definition kills any uses
InSetChanged = true;
if( DEBUG_LV > 1) {
cout << " +Def: "; printValue( Op ); cout << endl;
}
}
// To add an operand which is a use
void BBLiveVar::addUse(const Value *Op)
{
InSet.add( Op ); // An operand is a use - so add to use set
OutSet.remove( Op ); // remove if there is a def below this use
InSetChanged = true;
if( DEBUG_LV > 1) { // debug msg of level 2
cout << " Use: "; printValue( Op ); cout << endl;
}
}
bool BBLiveVar::applyTransferFunc() // calculates the InSet in terms of OutSet
{
// IMPORTANT: caller should check whether the OutSet changed
// (else no point in calling)
LiveVarSet OutMinusDef; // set to hold (Out[B] - Def[B])
OutMinusDef.setDifference( &OutSet, &DefSet);
InSetChanged = InSet.setUnion( &OutMinusDef );
OutSetChanged = false; // no change to OutSet since transf func applied
return InSetChanged;
}
// calculates Out set using In sets of the predecessors
bool BBLiveVar::setPropagate( LiveVarSet *const OutSet,
const LiveVarSet *const InSet,
const BasicBlock *const PredBB) {
LiveVarSet::const_iterator InIt;
pair<LiveVarSet::iterator, bool> result;
bool changed = false;
const BasicBlock *PredBBOfPhiArg;
// for all all elements in InSet
for( InIt = InSet->begin() ; InIt != InSet->end(); InIt++) {
PredBBOfPhiArg = PhiArgMap[ *InIt ];
// if this var is not a phi arg OR
// it's a phi arg and the var went down from this BB
if( !PredBBOfPhiArg || PredBBOfPhiArg == PredBB) {
result = OutSet->insert( *InIt ); // insert to this set
if( result.second == true) changed = true;
}
}
return changed;
}
// propogates in set to OutSets of PREDECESSORs
bool BBLiveVar::applyFlowFunc(BBToBBLiveVarMapType LVMap)
{
// IMPORTANT: caller should check whether inset changed
// (else no point in calling)
bool needAnotherIt= false; // did this BB change any OutSets of pred.s
// whose POId is lower
BasicBlock::pred_const_iterator PredBBI = BaseBB->pred_begin();
for( ; PredBBI != BaseBB->pred_end() ; PredBBI++) {
assert( *PredBBI ); // assert that the predecessor is valid
BBLiveVar *PredLVBB = LVMap[*PredBBI];
// do set union
if( setPropagate( &(PredLVBB->OutSet), &InSet, *PredBBI ) == true) {
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
{
cout << " Defs: "; DefSet.printSet(); cout << endl;
cout << " In: "; InSet.printSet(); cout << endl;
cout << " Out: "; OutSet.printSet(); cout << endl;
}
void BBLiveVar::printInOutSets() const
{
cout << " In: "; InSet.printSet(); cout << endl;
cout << " Out: "; OutSet.printSet(); cout << endl;
}
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