2 //***************************************************************************
7 // Register allocation for LLVM.
10 // 9/10/01 - Ruchira Sasanka - created.
11 //**************************************************************************/
13 #include "llvm/CodeGen/PhyRegAlloc.h"
14 #include "llvm/CodeGen/MachineInstr.h"
15 #include "llvm/Target/TargetMachine.h"
16 #include "llvm/Target/MachineFrameInfo.h"
19 // ***TODO: There are several places we add instructions. Validate the order
20 // of adding these instructions.
24 cl::Enum<RegAllocDebugLevel_t> DEBUG_RA("dregalloc", cl::NoFlags,
25 "enable register allocation debugging information",
26 clEnumValN(RA_DEBUG_None , "n", "disable debug output"),
27 clEnumValN(RA_DEBUG_Normal , "y", "enable debug output"),
28 clEnumValN(RA_DEBUG_Verbose, "v", "enable extra debug output"), 0);
31 //----------------------------------------------------------------------------
32 // Constructor: Init local composite objects and create register classes.
33 //----------------------------------------------------------------------------
34 PhyRegAlloc::PhyRegAlloc(Method *M,
35 const TargetMachine& tm,
36 MethodLiveVarInfo *const Lvi)
40 mcInfo(MachineCodeForMethod::get(M)),
41 LVI(Lvi), LRI(M, tm, RegClassList),
42 MRI( tm.getRegInfo() ),
43 NumOfRegClasses(MRI.getNumOfRegClasses()),
47 // **TODO: use an actual reserved color list
48 ReservedColorListType *RCL = new ReservedColorListType();
50 // create each RegisterClass and put in RegClassList
51 for( unsigned int rc=0; rc < NumOfRegClasses; rc++)
52 RegClassList.push_back( new RegClass(M, MRI.getMachineRegClass(rc), RCL) );
55 //----------------------------------------------------------------------------
56 // This method initally creates interference graphs (one in each reg class)
57 // and IGNodeList (one in each IG). The actual nodes will be pushed later.
58 //----------------------------------------------------------------------------
60 void PhyRegAlloc::createIGNodeListsAndIGs()
62 if(DEBUG_RA ) cout << "Creating LR lists ..." << endl;
65 LiveRangeMapType::const_iterator HMI = (LRI.getLiveRangeMap())->begin();
68 LiveRangeMapType::const_iterator HMIEnd = (LRI.getLiveRangeMap())->end();
70 for( ; HMI != HMIEnd ; ++HMI ) {
74 LiveRange *L = (*HMI).second; // get the LiveRange
78 cout << "\n*?!?Warning: Null liver range found for: ";
79 printValue( (*HMI).first) ; cout << endl;
83 // if the Value * is not null, and LR
84 // is not yet written to the IGNodeList
85 if( !(L->getUserIGNode()) ) {
87 RegClass *const RC = // RegClass of first value in the LR
88 //RegClassList [MRI.getRegClassIDOfValue(*(L->begin()))];
89 RegClassList[ L->getRegClass()->getID() ];
91 RC-> addLRToIG( L ); // add this LR to an IG
97 for( unsigned int rc=0; rc < NumOfRegClasses ; rc++)
98 RegClassList[ rc ]->createInterferenceGraph();
101 cout << "LRLists Created!" << endl;
106 //----------------------------------------------------------------------------
107 // This method will add all interferences at for a given instruction.
108 // Interence occurs only if the LR of Def (Inst or Arg) is of the same reg
109 // class as that of live var. The live var passed to this function is the
110 // LVset AFTER the instruction
111 //----------------------------------------------------------------------------
113 void PhyRegAlloc::addInterference(const Value *const Def,
114 const LiveVarSet *const LVSet,
115 const bool isCallInst) {
117 LiveVarSet::const_iterator LIt = LVSet->begin();
119 // get the live range of instruction
120 const LiveRange *const LROfDef = LRI.getLiveRangeForValue( Def );
122 IGNode *const IGNodeOfDef = LROfDef->getUserIGNode();
123 assert( IGNodeOfDef );
125 RegClass *const RCOfDef = LROfDef->getRegClass();
127 // for each live var in live variable set
128 for( ; LIt != LVSet->end(); ++LIt) {
131 cout << "< Def="; printValue(Def);
132 cout << ", Lvar="; printValue( *LIt); cout << "> ";
135 // get the live range corresponding to live var
136 LiveRange *const LROfVar = LRI.getLiveRangeForValue(*LIt );
138 // LROfVar can be null if it is a const since a const
139 // doesn't have a dominating def - see Assumptions above
142 if(LROfDef == LROfVar) // do not set interf for same LR
145 // if 2 reg classes are the same set interference
146 if( RCOfDef == LROfVar->getRegClass() ){
147 RCOfDef->setInterference( LROfDef, LROfVar);
151 else if(DEBUG_RA > 1) {
152 // we will not have LRs for values not explicitly allocated in the
153 // instruction stream (e.g., constants)
154 cout << " warning: no live range for " ;
155 printValue( *LIt); cout << endl; }
164 //----------------------------------------------------------------------------
165 // For a call instruction, this method sets the CallInterference flag in
166 // the LR of each variable live int the Live Variable Set live after the
167 // call instruction (except the return value of the call instruction - since
168 // the return value does not interfere with that call itself).
169 //----------------------------------------------------------------------------
171 void PhyRegAlloc::setCallInterferences(const MachineInstr *MInst,
172 const LiveVarSet *const LVSetAft )
174 // Now find the LR of the return value of the call
177 // We do this because, we look at the LV set *after* the instruction
178 // to determine, which LRs must be saved across calls. The return value
179 // of the call is live in this set - but it does not interfere with call
180 // (i.e., we can allocate a volatile register to the return value)
182 LiveRange *RetValLR = NULL;
184 const Value *RetVal = MRI.getCallInstRetVal( MInst );
187 RetValLR = LRI.getLiveRangeForValue( RetVal );
188 assert( RetValLR && "No LR for RetValue of call");
192 cout << "\n For call inst: " << *MInst;
194 LiveVarSet::const_iterator LIt = LVSetAft->begin();
196 // for each live var in live variable set after machine inst
197 for( ; LIt != LVSetAft->end(); ++LIt) {
199 // get the live range corresponding to live var
200 LiveRange *const LR = LRI.getLiveRangeForValue(*LIt );
202 if( LR && DEBUG_RA) {
203 cout << "\n\tLR Aft Call: ";
208 // LR can be null if it is a const since a const
209 // doesn't have a dominating def - see Assumptions above
210 if( LR && (LR != RetValLR) ) {
211 LR->setCallInterference();
213 cout << "\n ++Added call interf for LR: " ;
223 //----------------------------------------------------------------------------
224 // This method will walk thru code and create interferences in the IG of
226 //----------------------------------------------------------------------------
228 void PhyRegAlloc::buildInterferenceGraphs()
231 if(DEBUG_RA) cout << "Creating interference graphs ..." << endl;
233 Method::const_iterator BBI = Meth->begin(); // random iterator for BBs
235 for( ; BBI != Meth->end(); ++BBI) { // traverse BBs in random order
237 // get the iterator for machine instructions
238 const MachineCodeForBasicBlock& MIVec = (*BBI)->getMachineInstrVec();
239 MachineCodeForBasicBlock::const_iterator
240 MInstIterator = MIVec.begin();
242 // iterate over all the machine instructions in BB
243 for( ; MInstIterator != MIVec.end(); ++MInstIterator) {
245 const MachineInstr * MInst = *MInstIterator;
247 // get the LV set after the instruction
248 const LiveVarSet *const LVSetAI =
249 LVI->getLiveVarSetAfterMInst(MInst, *BBI);
251 const bool isCallInst = TM.getInstrInfo().isCall(MInst->getOpCode());
254 //cout << "\nFor call inst: " << *MInst;
256 // set the isCallInterference flag of each live range wich extends
257 // accross this call instruction. This information is used by graph
258 // coloring algo to avoid allocating volatile colors to live ranges
259 // that span across calls (since they have to be saved/restored)
260 setCallInterferences( MInst, LVSetAI);
264 // iterate over MI operands to find defs
265 for( MachineInstr::val_op_const_iterator OpI(MInst);!OpI.done(); ++OpI) {
268 // create a new LR iff this operand is a def
269 addInterference(*OpI, LVSetAI, isCallInst );
273 } // for all operands
276 // Also add interference for any implicit definitions in a machine
277 // instr (currently, only calls have this).
279 unsigned NumOfImpRefs = MInst->getNumImplicitRefs();
280 if( NumOfImpRefs > 0 ) {
281 for(unsigned z=0; z < NumOfImpRefs; z++)
282 if( MInst->implicitRefIsDefined(z) )
283 addInterference( MInst->getImplicitRef(z), LVSetAI, isCallInst );
287 // record phi instrns in PhiInstList
288 if( TM.getInstrInfo().isDummyPhiInstr(MInst->getOpCode()) )
289 PhiInstList.push_back( MInst );
292 } // for all machine instructions in BB
294 } // for all BBs in method
297 // add interferences for method arguments. Since there are no explict
298 // defs in method for args, we have to add them manually
300 addInterferencesForArgs(); // add interference for method args
303 cout << "Interference graphs calculted!" << endl;
310 //----------------------------------------------------------------------------
311 // This method will add interferences for incoming arguments to a method.
312 //----------------------------------------------------------------------------
313 void PhyRegAlloc::addInterferencesForArgs()
315 // get the InSet of root BB
316 const LiveVarSet *const InSet = LVI->getInSetOfBB( Meth->front() );
318 // get the argument list
319 const Method::ArgumentListType& ArgList = Meth->getArgumentList();
321 // get an iterator to arg list
322 Method::ArgumentListType::const_iterator ArgIt = ArgList.begin();
325 for( ; ArgIt != ArgList.end() ; ++ArgIt) { // for each argument
326 addInterference( *ArgIt, InSet, false ); // add interferences between
327 // args and LVars at start
329 cout << " - %% adding interference for argument ";
330 printValue( (const Value *) *ArgIt); cout << endl;
336 //----------------------------------------------------------------------------
337 // This method is called after register allocation is complete to set the
338 // allocated reisters in the machine code. This code will add register numbers
339 // to MachineOperands that contain a Value.
340 //----------------------------------------------------------------------------
342 void PhyRegAlloc::updateMachineCode()
345 Method::const_iterator BBI = Meth->begin(); // random iterator for BBs
347 for( ; BBI != Meth->end(); ++BBI) { // traverse BBs in random order
349 // get the iterator for machine instructions
350 MachineCodeForBasicBlock& MIVec = (*BBI)->getMachineInstrVec();
351 MachineCodeForBasicBlock::iterator MInstIterator = MIVec.begin();
353 // iterate over all the machine instructions in BB
354 for( ; MInstIterator != MIVec.end(); ++MInstIterator) {
356 MachineInstr *MInst = *MInstIterator;
358 // do not process Phis
359 if( (TM.getInstrInfo()).isPhi( MInst->getOpCode()) )
363 // if this machine instr is call, insert caller saving code
365 if( (TM.getInstrInfo()).isCall( MInst->getOpCode()) )
366 MRI.insertCallerSavingCode(MInst, *BBI, *this );
368 // If there are instructions to be added, *before* this machine
369 // instruction, add them now.
371 if( AddedInstrMap[ MInst ] ) {
373 deque<MachineInstr *> &IBef = (AddedInstrMap[MInst])->InstrnsBefore;
375 if( ! IBef.empty() ) {
377 deque<MachineInstr *>::iterator AdIt;
379 for( AdIt = IBef.begin(); AdIt != IBef.end() ; ++AdIt ) {
382 cerr << " PREPENDed instr: " << **AdIt << endl;
384 MInstIterator = MIVec.insert( MInstIterator, *AdIt );
392 // reset the stack offset for temporary variables since we may
393 // need that to spill
394 mcInfo.popAllTempValues(TM);
396 //for(MachineInstr::val_op_const_iterator OpI(MInst);!OpI.done();++OpI) {
398 for(unsigned OpNum=0; OpNum < MInst->getNumOperands(); ++OpNum) {
400 MachineOperand& Op = MInst->getOperand(OpNum);
402 if( Op.getOperandType() == MachineOperand::MO_VirtualRegister ||
403 Op.getOperandType() == MachineOperand::MO_CCRegister) {
405 const Value *const Val = Op.getVRegValue();
407 // delete this condition checking later (must assert if Val is null)
410 cout << "Warning: NULL Value found for operand" << endl;
413 assert( Val && "Value is NULL");
415 LiveRange *const LR = LRI.getLiveRangeForValue(Val);
419 // nothing to worry if it's a const or a label
422 cout << "*NO LR for operand : " << Op ;
423 cout << " [reg:" << Op.getAllocatedRegNum() << "]";
424 cout << " in inst:\t" << *MInst << endl;
427 // if register is not allocated, mark register as invalid
428 if( Op.getAllocatedRegNum() == -1)
429 Op.setRegForValue( MRI.getInvalidRegNum());
435 unsigned RCID = (LR->getRegClass())->getID();
437 if( LR->hasColor() ) {
438 Op.setRegForValue( MRI.getUnifiedRegNum(RCID, LR->getColor()) );
442 // LR did NOT receive a color (register). Now, insert spill code
443 // for spilled opeands in this machine instruction
445 //assert(0 && "LR must be spilled");
446 insertCode4SpilledLR(LR, MInst, *BBI, OpNum );
451 } // for each operand
454 // If there are instructions to be added *after* this machine
455 // instruction, add them now
457 if( AddedInstrMap[ MInst ] &&
458 ! (AddedInstrMap[ MInst ]->InstrnsAfter).empty() ) {
460 // if there are delay slots for this instruction, the instructions
461 // added after it must really go after the delayed instruction(s)
462 // So, we move the InstrAfter of the current instruction to the
463 // corresponding delayed instruction
466 if((delay=TM.getInstrInfo().getNumDelaySlots(MInst->getOpCode())) >0){
467 move2DelayedInstr(MInst, *(MInstIterator+delay) );
469 if(DEBUG_RA) cout<< "\nMoved an added instr after the delay slot";
475 // Here we can add the "instructions after" to the current
476 // instruction since there are no delay slots for this instruction
478 deque<MachineInstr *> &IAft = (AddedInstrMap[MInst])->InstrnsAfter;
480 if( ! IAft.empty() ) {
482 deque<MachineInstr *>::iterator AdIt;
484 ++MInstIterator; // advance to the next instruction
486 for( AdIt = IAft.begin(); AdIt != IAft.end() ; ++AdIt ) {
489 cerr << " APPENDed instr: " << **AdIt << endl;
491 MInstIterator = MIVec.insert( MInstIterator, *AdIt );
495 // MInsterator already points to the next instr. Since the
496 // for loop also increments it, decrement it to point to the
497 // instruction added last
506 } // for each machine instruction
512 //----------------------------------------------------------------------------
513 // This method inserts spill code for AN operand whose LR was spilled.
514 // This method may be called several times for a single machine instruction
515 // if it contains many spilled operands. Each time it is called, it finds
516 // a register which is not live at that instruction and also which is not
517 // used by other spilled operands of the same instruction. Then it uses
518 // this register temporarily to accomodate the spilled value.
519 //----------------------------------------------------------------------------
520 void PhyRegAlloc::insertCode4SpilledLR(const LiveRange *LR,
522 const BasicBlock *BB,
523 const unsigned OpNum) {
525 MachineOperand& Op = MInst->getOperand(OpNum);
526 bool isDef = MInst->operandIsDefined(OpNum);
527 unsigned RegType = MRI.getRegType( LR );
528 int SpillOff = LR->getSpillOffFromFP();
529 RegClass *RC = LR->getRegClass();
530 const LiveVarSet *LVSetBef = LVI->getLiveVarSetBeforeMInst(MInst, BB);
532 mcInfo.pushTempValue(TM, TM.findOptimalStorageSize(LR->getType()));
534 MachineInstr *MIBef=NULL, *AdIMid=NULL, *MIAft=NULL;
537 TmpReg = getUsableRegAtMI(RC, RegType, MInst,LVSetBef, MIBef, MIAft);
538 TmpReg = MRI.getUnifiedRegNum( RC->getID(), TmpReg );
541 // get the added instructions for this instruciton
542 AddedInstrns *AI = AddedInstrMap[ MInst ];
544 AI = new AddedInstrns();
545 AddedInstrMap[ MInst ] = AI;
552 // for a USE, we have to load the value of LR from stack to a TmpReg
553 // and use the TmpReg as one operand of instruction
555 // actual loading instruction
556 AdIMid = MRI.cpMem2RegMI(MRI.getFramePointer(), SpillOff, TmpReg, RegType);
559 (AI->InstrnsBefore).push_back(MIBef);
561 (AI->InstrnsBefore).push_back(AdIMid);
564 (AI->InstrnsAfter).push_front(MIAft);
568 else { // if this is a Def
570 // for a DEF, we have to store the value produced by this instruction
571 // on the stack position allocated for this LR
573 // actual storing instruction
574 AdIMid = MRI.cpReg2MemMI(TmpReg, MRI.getFramePointer(), SpillOff, RegType);
577 (AI->InstrnsBefore).push_back(MIBef);
579 (AI->InstrnsBefore).push_back(AdIMid);
582 (AI->InstrnsAfter).push_front(MIAft);
586 cerr << "\nFor Inst " << *MInst;
587 cerr << " - SPILLED LR: "; LR->printSet();
588 cerr << "\n - Added Instructions:";
589 if( MIBef ) cerr << *MIBef;
591 if( MIAft ) cerr << *MIAft;
593 Op.setRegForValue( TmpReg ); // set the opearnd
603 //----------------------------------------------------------------------------
604 // We can use the following method to get a temporary register to be used
605 // BEFORE any given machine instruction. If there is a register available,
606 // this method will simply return that register and set MIBef = MIAft = NULL.
607 // Otherwise, it will return a register and MIAft and MIBef will contain
608 // two instructions used to free up this returned register.
609 // Returned register number is the UNIFIED register number
610 //----------------------------------------------------------------------------
612 int PhyRegAlloc::getUsableRegAtMI(RegClass *RC,
614 const MachineInstr *MInst,
615 const LiveVarSet *LVSetBef,
617 MachineInstr *MIAft) {
619 int Reg = getUnusedRegAtMI(RC, MInst, LVSetBef);
620 Reg = MRI.getUnifiedRegNum(RC->getID(), Reg);
623 // we found an unused register, so we can simply used
624 MIBef = MIAft = NULL;
627 // we couldn't find an unused register. Generate code to free up a reg by
628 // saving it on stack and restoring after the instruction
630 /**** NOTE: THIS SHOULD USE THE RIGHT SIZE FOR THE REG BEING PUSHED ****/
631 int TmpOff = mcInfo.pushTempValue(TM, /*size*/ 8);
633 Reg = getRegNotUsedByThisInst(RC, MInst);
634 MIBef = MRI.cpReg2MemMI(Reg, MRI.getFramePointer(), TmpOff, RegType );
635 MIAft = MRI.cpMem2RegMI(MRI.getFramePointer(), TmpOff, Reg, RegType );
641 //----------------------------------------------------------------------------
642 // This method is called to get a new unused register that can be used to
643 // accomodate a spilled value.
644 // This method may be called several times for a single machine instruction
645 // if it contains many spilled operands. Each time it is called, it finds
646 // a register which is not live at that instruction and also which is not
647 // used by other spilled operands of the same instruction.
648 // Return register number is relative to the register class. NOT
650 //----------------------------------------------------------------------------
651 int PhyRegAlloc::getUnusedRegAtMI(RegClass *RC,
652 const MachineInstr *MInst,
653 const LiveVarSet *LVSetBef) {
655 unsigned NumAvailRegs = RC->getNumOfAvailRegs();
657 bool *IsColorUsedArr = RC->getIsColorUsedArr();
659 for(unsigned i=0; i < NumAvailRegs; i++)
660 IsColorUsedArr[i] = false;
662 LiveVarSet::const_iterator LIt = LVSetBef->begin();
664 // for each live var in live variable set after machine inst
665 for( ; LIt != LVSetBef->end(); ++LIt) {
667 // get the live range corresponding to live var
668 LiveRange *const LRofLV = LRI.getLiveRangeForValue(*LIt );
670 // LR can be null if it is a const since a const
671 // doesn't have a dominating def - see Assumptions above
673 if( LRofLV->hasColor() )
674 IsColorUsedArr[ LRofLV->getColor() ] = true;
677 // It is possible that one operand of this MInst was already spilled
678 // and it received some register temporarily. If that's the case,
679 // it is recorded in machine operand. We must skip such registers.
681 setRegsUsedByThisInst(RC, MInst);
683 unsigned c; // find first unused color
684 for( c=0; c < NumAvailRegs; c++)
685 if( ! IsColorUsedArr[ c ] ) break;
697 //----------------------------------------------------------------------------
698 // This method modifies the IsColorUsedArr of the register class passed to it.
699 // It sets the bits corresponding to the registers used by this machine
700 // instructions. Explicit operands are set.
701 //----------------------------------------------------------------------------
702 void PhyRegAlloc::setRegsUsedByThisInst(RegClass *RC,
703 const MachineInstr *MInst ) {
705 bool *IsColorUsedArr = RC->getIsColorUsedArr();
707 for(unsigned OpNum=0; OpNum < MInst->getNumOperands(); ++OpNum) {
709 const MachineOperand& Op = MInst->getOperand(OpNum);
711 if( Op.getOperandType() == MachineOperand::MO_VirtualRegister ||
712 Op.getOperandType() == MachineOperand::MO_CCRegister) {
714 const Value *const Val = Op.getVRegValue();
717 if( MRI.getRegClassIDOfValue( Val )== RC->getID() ) {
719 if( (Reg=Op.getAllocatedRegNum()) != -1)
720 IsColorUsedArr[ Reg ] = true;
726 // If there are implicit references, mark them as well
728 for(unsigned z=0; z < MInst->getNumImplicitRefs(); z++) {
730 LiveRange *const LRofImpRef =
731 LRI.getLiveRangeForValue( MInst->getImplicitRef(z) );
734 if( LRofImpRef->hasColor() )
735 IsColorUsedArr[ LRofImpRef->getColor() ] = true;
744 //----------------------------------------------------------------------------
745 // Get any other register in a register class, other than what is used
746 // by operands of a machine instruction.
747 //----------------------------------------------------------------------------
748 int PhyRegAlloc::getRegNotUsedByThisInst(RegClass *RC,
749 const MachineInstr *MInst) {
751 bool *IsColorUsedArr = RC->getIsColorUsedArr();
752 unsigned NumAvailRegs = RC->getNumOfAvailRegs();
755 for(unsigned i=0; i < NumAvailRegs ; i++)
756 IsColorUsedArr[i] = false;
758 setRegsUsedByThisInst(RC, MInst);
760 unsigned c; // find first unused color
761 for( c=0; c < RC->getNumOfAvailRegs(); c++)
762 if( ! IsColorUsedArr[ c ] ) break;
767 assert( 0 && "FATAL: No free register could be found in reg class!!");
775 //----------------------------------------------------------------------------
776 // If there are delay slots for an instruction, the instructions
777 // added after it must really go after the delayed instruction(s).
778 // So, we move the InstrAfter of that instruction to the
779 // corresponding delayed instruction using the following method.
781 //----------------------------------------------------------------------------
782 void PhyRegAlloc:: move2DelayedInstr(const MachineInstr *OrigMI,
783 const MachineInstr *DelayedMI) {
786 // "added after" instructions of the original instr
787 deque<MachineInstr *> &OrigAft = (AddedInstrMap[OrigMI])->InstrnsAfter;
789 // "added instructions" of the delayed instr
790 AddedInstrns *DelayAdI = AddedInstrMap[DelayedMI];
792 if(! DelayAdI ) { // create a new "added after" if necessary
793 DelayAdI = new AddedInstrns();
794 AddedInstrMap[DelayedMI] = DelayAdI;
797 // "added after" instructions of the delayed instr
798 deque<MachineInstr *> &DelayedAft = DelayAdI->InstrnsAfter;
800 // go thru all the "added after instructions" of the original instruction
801 // and append them to the "addded after instructions" of the delayed
804 deque<MachineInstr *>::iterator OrigAdIt;
806 for( OrigAdIt = OrigAft.begin(); OrigAdIt != OrigAft.end() ; ++OrigAdIt ) {
807 DelayedAft.push_back( *OrigAdIt );
810 // empty the "added after instructions" of the original instruction
815 //----------------------------------------------------------------------------
816 // This method prints the code with registers after register allocation is
818 //----------------------------------------------------------------------------
819 void PhyRegAlloc::printMachineCode()
822 cout << endl << ";************** Method ";
823 cout << Meth->getName() << " *****************" << endl;
825 Method::const_iterator BBI = Meth->begin(); // random iterator for BBs
827 for( ; BBI != Meth->end(); ++BBI) { // traverse BBs in random order
829 cout << endl ; printLabel( *BBI); cout << ": ";
831 // get the iterator for machine instructions
832 MachineCodeForBasicBlock& MIVec = (*BBI)->getMachineInstrVec();
833 MachineCodeForBasicBlock::iterator MInstIterator = MIVec.begin();
835 // iterate over all the machine instructions in BB
836 for( ; MInstIterator != MIVec.end(); ++MInstIterator) {
838 MachineInstr *const MInst = *MInstIterator;
841 cout << endl << "\t";
842 cout << TargetInstrDescriptors[MInst->getOpCode()].opCodeString;
845 //for(MachineInstr::val_op_const_iterator OpI(MInst);!OpI.done();++OpI) {
847 for(unsigned OpNum=0; OpNum < MInst->getNumOperands(); ++OpNum) {
849 MachineOperand& Op = MInst->getOperand(OpNum);
851 if( Op.getOperandType() == MachineOperand::MO_VirtualRegister ||
852 Op.getOperandType() == MachineOperand::MO_CCRegister /*||
853 Op.getOperandType() == MachineOperand::MO_PCRelativeDisp*/ ) {
855 const Value *const Val = Op.getVRegValue () ;
856 // ****this code is temporary till NULL Values are fixed
858 cout << "\t<*NULL*>";
862 // if a label or a constant
863 if( (Val->getValueType() == Value::BasicBlockVal) ) {
865 cout << "\t"; printLabel( Op.getVRegValue () );
868 // else it must be a register value
869 const int RegNum = Op.getAllocatedRegNum();
871 cout << "\t" << "%" << MRI.getUnifiedRegName( RegNum );
875 else if(Op.getOperandType() == MachineOperand::MO_MachineRegister) {
876 cout << "\t" << "%" << MRI.getUnifiedRegName(Op.getMachineRegNum());
880 cout << "\t" << Op; // use dump field
885 unsigned NumOfImpRefs = MInst->getNumImplicitRefs();
886 if( NumOfImpRefs > 0 ) {
888 cout << "\tImplicit:";
890 for(unsigned z=0; z < NumOfImpRefs; z++) {
891 printValue( MInst->getImplicitRef(z) );
897 } // for all machine instructions
908 //----------------------------------------------------------------------------
910 //----------------------------------------------------------------------------
912 void PhyRegAlloc::colorCallRetArgs()
915 CallRetInstrListType &CallRetInstList = LRI.getCallRetInstrList();
916 CallRetInstrListType::const_iterator It = CallRetInstList.begin();
918 for( ; It != CallRetInstList.end(); ++It ) {
920 const MachineInstr *const CRMI = *It;
921 unsigned OpCode = CRMI->getOpCode();
923 // get the added instructions for this Call/Ret instruciton
924 AddedInstrns *AI = AddedInstrMap[ CRMI ];
926 AI = new AddedInstrns();
927 AddedInstrMap[ CRMI ] = AI;
930 // Tmp stack poistions are needed by some calls that have spilled args
931 // So reset it before we call each such method
932 mcInfo.popAllTempValues(TM);
934 if( (TM.getInstrInfo()).isCall( OpCode ) )
935 MRI.colorCallArgs( CRMI, LRI, AI, *this );
937 else if ( (TM.getInstrInfo()).isReturn(OpCode) )
938 MRI.colorRetValue( CRMI, LRI, AI );
940 else assert( 0 && "Non Call/Ret instrn in CallRetInstrList\n" );
948 //----------------------------------------------------------------------------
950 //----------------------------------------------------------------------------
951 void PhyRegAlloc::colorIncomingArgs()
953 const BasicBlock *const FirstBB = Meth->front();
954 const MachineInstr *FirstMI = *((FirstBB->getMachineInstrVec()).begin());
955 assert( FirstMI && "No machine instruction in entry BB");
957 AddedInstrns *AI = AddedInstrMap[ FirstMI ];
959 AI = new AddedInstrns();
960 AddedInstrMap[ FirstMI ] = AI;
963 MRI.colorMethodArgs(Meth, LRI, AI );
967 //----------------------------------------------------------------------------
968 // Used to generate a label for a basic block
969 //----------------------------------------------------------------------------
970 void PhyRegAlloc::printLabel(const Value *const Val)
973 cout << Val->getName();
975 cout << "Label" << Val;
979 //----------------------------------------------------------------------------
980 // This method calls setSugColorUsable method of each live range. This
981 // will determine whether the suggested color of LR is really usable.
982 // A suggested color is not usable when the suggested color is volatile
983 // AND when there are call interferences
984 //----------------------------------------------------------------------------
986 void PhyRegAlloc::markUnusableSugColors()
988 if(DEBUG_RA ) cout << "\nmarking unusable suggested colors ..." << endl;
991 LiveRangeMapType::const_iterator HMI = (LRI.getLiveRangeMap())->begin();
992 LiveRangeMapType::const_iterator HMIEnd = (LRI.getLiveRangeMap())->end();
994 for( ; HMI != HMIEnd ; ++HMI ) {
998 LiveRange *L = (*HMI).second; // get the LiveRange
1001 if( L->hasSuggestedColor() ) {
1003 int RCID = (L->getRegClass())->getID();
1004 if( MRI.isRegVolatile( RCID, L->getSuggestedColor()) &&
1005 L->isCallInterference() )
1006 L->setSuggestedColorUsable( false );
1008 L->setSuggestedColorUsable( true );
1010 } // if L->hasSuggestedColor()
1012 } // for all LR's in hash map
1017 //----------------------------------------------------------------------------
1018 // The following method will set the stack offsets of the live ranges that
1019 // are decided to be spillled. This must be called just after coloring the
1020 // LRs using the graph coloring algo. For each live range that is spilled,
1021 // this method allocate a new spill position on the stack.
1022 //----------------------------------------------------------------------------
1024 void PhyRegAlloc::allocateStackSpace4SpilledLRs()
1026 if(DEBUG_RA ) cout << "\nsetting LR stack offsets ..." << endl;
1028 // hash map iterator
1029 LiveRangeMapType::const_iterator HMI = (LRI.getLiveRangeMap())->begin();
1030 LiveRangeMapType::const_iterator HMIEnd = (LRI.getLiveRangeMap())->end();
1032 for( ; HMI != HMIEnd ; ++HMI ) {
1033 if( (*HMI).first ) {
1034 LiveRange *L = (*HMI).second; // get the LiveRange
1036 if( ! L->hasColor() )
1037 L->setSpillOffFromFP(mcInfo.allocateSpilledValue(TM,L->getType()));
1039 } // for all LR's in hash map
1044 //----------------------------------------------------------------------------
1045 // The entry pont to Register Allocation
1046 //----------------------------------------------------------------------------
1048 void PhyRegAlloc::allocateRegisters()
1051 // make sure that we put all register classes into the RegClassList
1052 // before we call constructLiveRanges (now done in the constructor of
1053 // PhyRegAlloc class).
1055 constructLiveRanges(); // create LR info
1058 LRI.printLiveRanges();
1060 createIGNodeListsAndIGs(); // create IGNode list and IGs
1062 buildInterferenceGraphs(); // build IGs in all reg classes
1066 // print all LRs in all reg classes
1067 for( unsigned int rc=0; rc < NumOfRegClasses ; rc++)
1068 RegClassList[ rc ]->printIGNodeList();
1070 // print IGs in all register classes
1071 for( unsigned int rc=0; rc < NumOfRegClasses ; rc++)
1072 RegClassList[ rc ]->printIG();
1075 LRI.coalesceLRs(); // coalesce all live ranges
1077 // coalscing could not get rid of all phi's, add phi elimination
1079 // insertPhiEleminateInstrns();
1082 // print all LRs in all reg classes
1083 for( unsigned int rc=0; rc < NumOfRegClasses ; rc++)
1084 RegClassList[ rc ]->printIGNodeList();
1086 // print IGs in all register classes
1087 for( unsigned int rc=0; rc < NumOfRegClasses ; rc++)
1088 RegClassList[ rc ]->printIG();
1092 // mark un-usable suggested color before graph coloring algorithm.
1093 // When this is done, the graph coloring algo will not reserve
1094 // suggested color unnecessarily - they can be used by another LR
1095 markUnusableSugColors();
1097 // color all register classes using the graph coloring algo
1098 for( unsigned int rc=0; rc < NumOfRegClasses ; rc++)
1099 RegClassList[ rc ]->colorAllRegs();
1101 // Atter grpah coloring, if some LRs did not receive a color (i.e, spilled)
1102 // a poistion for such spilled LRs
1103 allocateStackSpace4SpilledLRs();
1105 // color incoming args and call args
1106 colorIncomingArgs();
1110 updateMachineCode();
1112 MachineCodeForMethod::get(Meth).dump();
1113 printMachineCode(); // only for DEBUGGING