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llvm-project/llvm/lib/CodeGen/RegAlloc/PhyRegAlloc.cpp

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// $Id$
//***************************************************************************
// File:
// PhyRegAlloc.cpp
//
// Purpose:
// Register allocation for LLVM.
//
// History:
// 9/10/01 - Ruchira Sasanka - created.
//**************************************************************************/
#include "llvm/CodeGen/PhyRegAlloc.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/MachineFrameInfo.h"
// ***TODO: There are several places we add instructions. Validate the order
// of adding these instructions.
cl::Enum<RegAllocDebugLevel_t> DEBUG_RA("dregalloc", cl::NoFlags,
"enable register allocation debugging information",
clEnumValN(RA_DEBUG_None , "n", "disable debug output"),
clEnumValN(RA_DEBUG_Normal , "y", "enable debug output"),
clEnumValN(RA_DEBUG_Verbose, "v", "enable extra debug output"), 0);
//----------------------------------------------------------------------------
// Constructor: Init local composite objects and create register classes.
//----------------------------------------------------------------------------
PhyRegAlloc::PhyRegAlloc(Method *M,
const TargetMachine& tm,
MethodLiveVarInfo *const Lvi)
: RegClassList(),
TM(tm),
Meth(M),
mcInfo(MachineCodeForMethod::get(M)),
LVI(Lvi), LRI(M, tm, RegClassList),
MRI( tm.getRegInfo() ),
NumOfRegClasses(MRI.getNumOfRegClasses()),
AddedInstrMap()
/*, PhiInstList()*/
{
// **TODO: use an actual reserved color list
ReservedColorListType *RCL = new ReservedColorListType();
// create each RegisterClass and put in RegClassList
for( unsigned int rc=0; rc < NumOfRegClasses; rc++)
RegClassList.push_back( new RegClass(M, MRI.getMachineRegClass(rc), RCL) );
}
//----------------------------------------------------------------------------
// This method initally creates interference graphs (one in each reg class)
// and IGNodeList (one in each IG). The actual nodes will be pushed later.
//----------------------------------------------------------------------------
void PhyRegAlloc::createIGNodeListsAndIGs()
{
if(DEBUG_RA ) cout << "Creating LR lists ..." << endl;
// hash map iterator
LiveRangeMapType::const_iterator HMI = (LRI.getLiveRangeMap())->begin();
// hash map end
LiveRangeMapType::const_iterator HMIEnd = (LRI.getLiveRangeMap())->end();
for( ; HMI != HMIEnd ; ++HMI ) {
if( (*HMI).first ) {
LiveRange *L = (*HMI).second; // get the LiveRange
if( !L) {
if( DEBUG_RA) {
cout << "\n*?!?Warning: Null liver range found for: ";
printValue( (*HMI).first) ; cout << endl;
}
continue;
}
// if the Value * is not null, and LR
// is not yet written to the IGNodeList
if( !(L->getUserIGNode()) ) {
RegClass *const RC = // RegClass of first value in the LR
//RegClassList [MRI.getRegClassIDOfValue(*(L->begin()))];
RegClassList[ L->getRegClass()->getID() ];
RC-> addLRToIG( L ); // add this LR to an IG
}
}
}
// init RegClassList
for( unsigned int rc=0; rc < NumOfRegClasses ; rc++)
RegClassList[ rc ]->createInterferenceGraph();
if( DEBUG_RA)
cout << "LRLists Created!" << endl;
}
//----------------------------------------------------------------------------
// This method will add all interferences at for a given instruction.
// Interence occurs only if the LR of Def (Inst or Arg) is of the same reg
// class as that of live var. The live var passed to this function is the
// LVset AFTER the instruction
//----------------------------------------------------------------------------
void PhyRegAlloc::addInterference(const Value *const Def,
const LiveVarSet *const LVSet,
const bool isCallInst) {
LiveVarSet::const_iterator LIt = LVSet->begin();
// get the live range of instruction
const LiveRange *const LROfDef = LRI.getLiveRangeForValue( Def );
IGNode *const IGNodeOfDef = LROfDef->getUserIGNode();
assert( IGNodeOfDef );
RegClass *const RCOfDef = LROfDef->getRegClass();
// for each live var in live variable set
for( ; LIt != LVSet->end(); ++LIt) {
if( DEBUG_RA > 1) {
cout << "< Def="; printValue(Def);
cout << ", Lvar="; printValue( *LIt); cout << "> ";
}
// get the live range corresponding to live var
LiveRange *const LROfVar = LRI.getLiveRangeForValue(*LIt );
// LROfVar can be null if it is a const since a const
// doesn't have a dominating def - see Assumptions above
if( LROfVar) {
if(LROfDef == LROfVar) // do not set interf for same LR
continue;
// if 2 reg classes are the same set interference
if( RCOfDef == LROfVar->getRegClass() ){
RCOfDef->setInterference( LROfDef, LROfVar);
}
else if(DEBUG_RA > 1) {
// we will not have LRs for values not explicitly allocated in the
// instruction stream (e.g., constants)
cout << " warning: no live range for " ;
printValue( *LIt); cout << endl; }
}
}
}
//----------------------------------------------------------------------------
// For a call instruction, this method sets the CallInterference flag in
// the LR of each variable live int the Live Variable Set live after the
// call instruction (except the return value of the call instruction - since
// the return value does not interfere with that call itself).
//----------------------------------------------------------------------------
void PhyRegAlloc::setCallInterferences(const MachineInstr *MInst,
const LiveVarSet *const LVSetAft )
{
// Now find the LR of the return value of the call
// We do this because, we look at the LV set *after* the instruction
// to determine, which LRs must be saved across calls. The return value
// of the call is live in this set - but it does not interfere with call
// (i.e., we can allocate a volatile register to the return value)
LiveRange *RetValLR = NULL;
const Value *RetVal = MRI.getCallInstRetVal( MInst );
if( RetVal ) {
RetValLR = LRI.getLiveRangeForValue( RetVal );
assert( RetValLR && "No LR for RetValue of call");
}
if( DEBUG_RA)
cout << "\n For call inst: " << *MInst;
LiveVarSet::const_iterator LIt = LVSetAft->begin();
// for each live var in live variable set after machine inst
for( ; LIt != LVSetAft->end(); ++LIt) {
// get the live range corresponding to live var
LiveRange *const LR = LRI.getLiveRangeForValue(*LIt );
if( LR && DEBUG_RA) {
cout << "\n\tLR Aft Call: ";
LR->printSet();
}
// LR can be null if it is a const since a const
// doesn't have a dominating def - see Assumptions above
if( LR && (LR != RetValLR) ) {
LR->setCallInterference();
if( DEBUG_RA) {
cout << "\n ++Added call interf for LR: " ;
LR->printSet();
}
}
}
}
//----------------------------------------------------------------------------
// This method will walk thru code and create interferences in the IG of
// each RegClass.
//----------------------------------------------------------------------------
void PhyRegAlloc::buildInterferenceGraphs()
{
if(DEBUG_RA) cout << "Creating interference graphs ..." << endl;
Method::const_iterator BBI = Meth->begin(); // random iterator for BBs
for( ; BBI != Meth->end(); ++BBI) { // traverse BBs in random order
// get the iterator for machine instructions
const MachineCodeForBasicBlock& MIVec = (*BBI)->getMachineInstrVec();
MachineCodeForBasicBlock::const_iterator
MInstIterator = MIVec.begin();
// iterate over all the machine instructions in BB
for( ; MInstIterator != MIVec.end(); ++MInstIterator) {
const MachineInstr * MInst = *MInstIterator;
// get the LV set after the instruction
const LiveVarSet *const LVSetAI =
LVI->getLiveVarSetAfterMInst(MInst, *BBI);
const bool isCallInst = TM.getInstrInfo().isCall(MInst->getOpCode());
if( isCallInst ) {
//cout << "\nFor call inst: " << *MInst;
// set the isCallInterference flag of each live range wich extends
// accross this call instruction. This information is used by graph
// coloring algo to avoid allocating volatile colors to live ranges
// that span across calls (since they have to be saved/restored)
setCallInterferences( MInst, LVSetAI);
}
// iterate over MI operands to find defs
for( MachineInstr::val_op_const_iterator OpI(MInst);!OpI.done(); ++OpI) {
if( OpI.isDef() ) {
// create a new LR iff this operand is a def
addInterference(*OpI, LVSetAI, isCallInst );
} //if this is a def
} // for all operands
// Also add interference for any implicit definitions in a machine
// instr (currently, only calls have this).
unsigned NumOfImpRefs = MInst->getNumImplicitRefs();
if( NumOfImpRefs > 0 ) {
for(unsigned z=0; z < NumOfImpRefs; z++)
if( MInst->implicitRefIsDefined(z) )
addInterference( MInst->getImplicitRef(z), LVSetAI, isCallInst );
}
/*
// record phi instrns in PhiInstList
if( TM.getInstrInfo().isDummyPhiInstr(MInst->getOpCode()) )
PhiInstList.push_back( MInst );
*/
} // for all machine instructions in BB
} // for all BBs in method
// add interferences for method arguments. Since there are no explict
// defs in method for args, we have to add them manually
addInterferencesForArgs(); // add interference for method args
if( DEBUG_RA)
cout << "Interference graphs calculted!" << endl;
}
//----------------------------------------------------------------------------
// This method will add interferences for incoming arguments to a method.
//----------------------------------------------------------------------------
void PhyRegAlloc::addInterferencesForArgs()
{
// get the InSet of root BB
const LiveVarSet *const InSet = LVI->getInSetOfBB( Meth->front() );
// get the argument list
const Method::ArgumentListType& ArgList = Meth->getArgumentList();
// get an iterator to arg list
Method::ArgumentListType::const_iterator ArgIt = ArgList.begin();
for( ; ArgIt != ArgList.end() ; ++ArgIt) { // for each argument
addInterference( *ArgIt, InSet, false ); // add interferences between
// args and LVars at start
if( DEBUG_RA > 1) {
cout << " - %% adding interference for argument ";
printValue( (const Value *) *ArgIt); cout << endl;
}
}
}
//----------------------------------------------------------------------------
// This method is called after register allocation is complete to set the
// allocated reisters in the machine code. This code will add register numbers
// to MachineOperands that contain a Value.
//----------------------------------------------------------------------------
void PhyRegAlloc::updateMachineCode()
{
Method::const_iterator BBI = Meth->begin(); // random iterator for BBs
for( ; BBI != Meth->end(); ++BBI) { // traverse BBs in random order
// get the iterator for machine instructions
MachineCodeForBasicBlock& MIVec = (*BBI)->getMachineInstrVec();
MachineCodeForBasicBlock::iterator MInstIterator = MIVec.begin();
// iterate over all the machine instructions in BB
for( ; MInstIterator != MIVec.end(); ++MInstIterator) {
MachineInstr *MInst = *MInstIterator;
// do not process Phis
if( (TM.getInstrInfo()).isPhi( MInst->getOpCode()) )
continue;
// if this machine instr is call, insert caller saving code
if( (TM.getInstrInfo()).isCall( MInst->getOpCode()) )
MRI.insertCallerSavingCode(MInst, *BBI, *this );
// If there are instructions to be added, *before* this machine
// instruction, add them now.
if( AddedInstrMap[ MInst ] ) {
deque<MachineInstr *> &IBef = (AddedInstrMap[MInst])->InstrnsBefore;
if( ! IBef.empty() ) {
deque<MachineInstr *>::iterator AdIt;
for( AdIt = IBef.begin(); AdIt != IBef.end() ; ++AdIt ) {
if( DEBUG_RA )
cerr << " PREPENDed instr: " << **AdIt << endl;
MInstIterator = MIVec.insert( MInstIterator, *AdIt );
++MInstIterator;
}
}
}
// reset the stack offset for temporary variables since we may
// need that to spill
mcInfo.popAllTempValues(TM);
//for(MachineInstr::val_op_const_iterator OpI(MInst);!OpI.done();++OpI) {
for(unsigned OpNum=0; OpNum < MInst->getNumOperands(); ++OpNum) {
MachineOperand& Op = MInst->getOperand(OpNum);
if( Op.getOperandType() == MachineOperand::MO_VirtualRegister ||
Op.getOperandType() == MachineOperand::MO_CCRegister) {
const Value *const Val = Op.getVRegValue();
// delete this condition checking later (must assert if Val is null)
if( !Val) {
if (DEBUG_RA)
cout << "Warning: NULL Value found for operand" << endl;
continue;
}
assert( Val && "Value is NULL");
LiveRange *const LR = LRI.getLiveRangeForValue(Val);
if ( !LR ) {
// nothing to worry if it's a const or a label
if (DEBUG_RA) {
cout << "*NO LR for operand : " << Op ;
cout << " [reg:" << Op.getAllocatedRegNum() << "]";
cout << " in inst:\t" << *MInst << endl;
}
// if register is not allocated, mark register as invalid
if( Op.getAllocatedRegNum() == -1)
Op.setRegForValue( MRI.getInvalidRegNum());
continue;
}
unsigned RCID = (LR->getRegClass())->getID();
if( LR->hasColor() ) {
Op.setRegForValue( MRI.getUnifiedRegNum(RCID, LR->getColor()) );
}
else {
// LR did NOT receive a color (register). Now, insert spill code
// for spilled opeands in this machine instruction
//assert(0 && "LR must be spilled");
insertCode4SpilledLR(LR, MInst, *BBI, OpNum );
}
}
} // for each operand
// If there are instructions to be added *after* this machine
// instruction, add them now
if( AddedInstrMap[ MInst ] &&
! (AddedInstrMap[ MInst ]->InstrnsAfter).empty() ) {
// if there are delay slots for this instruction, the instructions
// added after it must really go after the delayed instruction(s)
// So, we move the InstrAfter of the current instruction to the
// corresponding delayed instruction
unsigned delay;
if((delay=TM.getInstrInfo().getNumDelaySlots(MInst->getOpCode())) >0){
move2DelayedInstr(MInst, *(MInstIterator+delay) );
if(DEBUG_RA) cout<< "\nMoved an added instr after the delay slot";
}
else {
// Here we can add the "instructions after" to the current
// instruction since there are no delay slots for this instruction
deque<MachineInstr *> &IAft = (AddedInstrMap[MInst])->InstrnsAfter;
if( ! IAft.empty() ) {
deque<MachineInstr *>::iterator AdIt;
++MInstIterator; // advance to the next instruction
for( AdIt = IAft.begin(); AdIt != IAft.end() ; ++AdIt ) {
if(DEBUG_RA)
cerr << " APPENDed instr: " << **AdIt << endl;
MInstIterator = MIVec.insert( MInstIterator, *AdIt );
++MInstIterator;
}
// MInsterator already points to the next instr. Since the
// for loop also increments it, decrement it to point to the
// instruction added last
--MInstIterator;
}
} // if not delay
}
} // for each machine instruction
}
}
//----------------------------------------------------------------------------
// This method inserts spill code for AN operand whose LR was spilled.
// This method may be called several times for a single machine instruction
// if it contains many spilled operands. Each time it is called, it finds
// a register which is not live at that instruction and also which is not
// used by other spilled operands of the same instruction. Then it uses
// this register temporarily to accomodate the spilled value.
//----------------------------------------------------------------------------
void PhyRegAlloc::insertCode4SpilledLR(const LiveRange *LR,
MachineInstr *MInst,
const BasicBlock *BB,
const unsigned OpNum) {
MachineOperand& Op = MInst->getOperand(OpNum);
bool isDef = MInst->operandIsDefined(OpNum);
unsigned RegType = MRI.getRegType( LR );
int SpillOff = LR->getSpillOffFromFP();
RegClass *RC = LR->getRegClass();
const LiveVarSet *LVSetBef = LVI->getLiveVarSetBeforeMInst(MInst, BB);
/**** NOTE: THIS SHOULD USE THE RIGHT SIZE FOR THE REG BEING PUSHED ****/
int TmpOff =
mcInfo.pushTempValue(TM, 8 /* TM.findOptimalStorageSize(LR->getType()) */);
MachineInstr *MIBef=NULL, *AdIMid=NULL, *MIAft=NULL;
int TmpReg;
TmpReg = getUsableRegAtMI(RC, RegType, MInst,LVSetBef, MIBef, MIAft);
TmpReg = MRI.getUnifiedRegNum( RC->getID(), TmpReg );
// get the added instructions for this instruciton
AddedInstrns *AI = AddedInstrMap[ MInst ];
if ( !AI ) {
AI = new AddedInstrns();
AddedInstrMap[ MInst ] = AI;
}
if( !isDef ) {
// for a USE, we have to load the value of LR from stack to a TmpReg
// and use the TmpReg as one operand of instruction
// actual loading instruction
AdIMid = MRI.cpMem2RegMI(MRI.getFramePointer(), SpillOff, TmpReg, RegType);
if( MIBef )
(AI->InstrnsBefore).push_back(MIBef);
(AI->InstrnsBefore).push_back(AdIMid);
if( MIAft)
(AI->InstrnsAfter).push_front(MIAft);
}
else { // if this is a Def
// for a DEF, we have to store the value produced by this instruction
// on the stack position allocated for this LR
// actual storing instruction
AdIMid = MRI.cpReg2MemMI(TmpReg, MRI.getFramePointer(), SpillOff, RegType);
if( MIBef )
(AI->InstrnsBefore).push_back(MIBef);
(AI->InstrnsBefore).push_back(AdIMid);
if( MIAft)
(AI->InstrnsAfter).push_front(MIAft);
} // if !DEF
cerr << "\nFor Inst " << *MInst;
cerr << " - SPILLED LR: "; LR->printSet();
cerr << "\n - Added Instructions:";
if( MIBef ) cerr << *MIBef;
cerr << *AdIMid;
if( MIAft ) cerr << *MIAft;
Op.setRegForValue( TmpReg ); // set the opearnd
}
//----------------------------------------------------------------------------
// We can use the following method to get a temporary register to be used
// BEFORE any given machine instruction. If there is a register available,
// this method will simply return that register and set MIBef = MIAft = NULL.
// Otherwise, it will return a register and MIAft and MIBef will contain
// two instructions used to free up this returned register.
// Returned register number is the UNIFIED register number
//----------------------------------------------------------------------------
int PhyRegAlloc::getUsableRegAtMI(RegClass *RC,
const int RegType,
const MachineInstr *MInst,
const LiveVarSet *LVSetBef,
MachineInstr *MIBef,
MachineInstr *MIAft) {
int Reg = getUnusedRegAtMI(RC, MInst, LVSetBef);
Reg = MRI.getUnifiedRegNum(RC->getID(), Reg);
if( Reg != -1) {
// we found an unused register, so we can simply used
MIBef = MIAft = NULL;
}
else {
// we couldn't find an unused register. Generate code to free up a reg by
// saving it on stack and restoring after the instruction
/**** NOTE: THIS SHOULD USE THE RIGHT SIZE FOR THE REG BEING PUSHED ****/
int TmpOff = mcInfo.pushTempValue(TM, /*size*/ 8);
Reg = getRegNotUsedByThisInst(RC, MInst);
MIBef = MRI.cpReg2MemMI(Reg, MRI.getFramePointer(), TmpOff, RegType );
MIAft = MRI.cpMem2RegMI(MRI.getFramePointer(), TmpOff, Reg, RegType );
}
return Reg;
}
//----------------------------------------------------------------------------
// This method is called to get a new unused register that can be used to
// accomodate a spilled value.
// This method may be called several times for a single machine instruction
// if it contains many spilled operands. Each time it is called, it finds
// a register which is not live at that instruction and also which is not
// used by other spilled operands of the same instruction.
// Return register number is relative to the register class. NOT
// unified number
//----------------------------------------------------------------------------
int PhyRegAlloc::getUnusedRegAtMI(RegClass *RC,
const MachineInstr *MInst,
const LiveVarSet *LVSetBef) {
unsigned NumAvailRegs = RC->getNumOfAvailRegs();
bool *IsColorUsedArr = RC->getIsColorUsedArr();
for(unsigned i=0; i < NumAvailRegs; i++)
IsColorUsedArr[i] = false;
LiveVarSet::const_iterator LIt = LVSetBef->begin();
// for each live var in live variable set after machine inst
for( ; LIt != LVSetBef->end(); ++LIt) {
// get the live range corresponding to live var
LiveRange *const LRofLV = LRI.getLiveRangeForValue(*LIt );
// LR can be null if it is a const since a const
// doesn't have a dominating def - see Assumptions above
if( LRofLV )
if( LRofLV->hasColor() )
IsColorUsedArr[ LRofLV->getColor() ] = true;
}
// It is possible that one operand of this MInst was already spilled
// and it received some register temporarily. If that's the case,
// it is recorded in machine operand. We must skip such registers.
setRegsUsedByThisInst(RC, MInst);
unsigned c; // find first unused color
for( c=0; c < NumAvailRegs; c++)
if( ! IsColorUsedArr[ c ] ) break;
if(c < NumAvailRegs)
return c;
else
return -1;
}
//----------------------------------------------------------------------------
// This method modifies the IsColorUsedArr of the register class passed to it.
// It sets the bits corresponding to the registers used by this machine
// instructions. Explicit operands are set.
//----------------------------------------------------------------------------
void PhyRegAlloc::setRegsUsedByThisInst(RegClass *RC,
const MachineInstr *MInst ) {
bool *IsColorUsedArr = RC->getIsColorUsedArr();
for(unsigned OpNum=0; OpNum < MInst->getNumOperands(); ++OpNum) {
const MachineOperand& Op = MInst->getOperand(OpNum);
if( Op.getOperandType() == MachineOperand::MO_VirtualRegister ||
Op.getOperandType() == MachineOperand::MO_CCRegister) {
const Value *const Val = Op.getVRegValue();
if( !Val )
if( MRI.getRegClassIDOfValue( Val )== RC->getID() ) {
int Reg;
if( (Reg=Op.getAllocatedRegNum()) != -1)
IsColorUsedArr[ Reg ] = true;
}
}
}
// If there are implicit references, mark them as well
for(unsigned z=0; z < MInst->getNumImplicitRefs(); z++) {
LiveRange *const LRofImpRef =
LRI.getLiveRangeForValue( MInst->getImplicitRef(z) );
if( LRofImpRef )
if( LRofImpRef->hasColor() )
IsColorUsedArr[ LRofImpRef->getColor() ] = true;
}
}
//----------------------------------------------------------------------------
// Get any other register in a register class, other than what is used
// by operands of a machine instruction.
//----------------------------------------------------------------------------
int PhyRegAlloc::getRegNotUsedByThisInst(RegClass *RC,
const MachineInstr *MInst) {
bool *IsColorUsedArr = RC->getIsColorUsedArr();
unsigned NumAvailRegs = RC->getNumOfAvailRegs();
for(unsigned i=0; i < NumAvailRegs ; i++)
IsColorUsedArr[i] = false;
setRegsUsedByThisInst(RC, MInst);
unsigned c; // find first unused color
for( c=0; c < RC->getNumOfAvailRegs(); c++)
if( ! IsColorUsedArr[ c ] ) break;
if(c < NumAvailRegs)
return c;
else
assert( 0 && "FATAL: No free register could be found in reg class!!");
}
//----------------------------------------------------------------------------
// If there are delay slots for an instruction, the instructions
// added after it must really go after the delayed instruction(s).
// So, we move the InstrAfter of that instruction to the
// corresponding delayed instruction using the following method.
//----------------------------------------------------------------------------
void PhyRegAlloc:: move2DelayedInstr(const MachineInstr *OrigMI,
const MachineInstr *DelayedMI) {
// "added after" instructions of the original instr
deque<MachineInstr *> &OrigAft = (AddedInstrMap[OrigMI])->InstrnsAfter;
// "added instructions" of the delayed instr
AddedInstrns *DelayAdI = AddedInstrMap[DelayedMI];
if(! DelayAdI ) { // create a new "added after" if necessary
DelayAdI = new AddedInstrns();
AddedInstrMap[DelayedMI] = DelayAdI;
}
// "added after" instructions of the delayed instr
deque<MachineInstr *> &DelayedAft = DelayAdI->InstrnsAfter;
// go thru all the "added after instructions" of the original instruction
// and append them to the "addded after instructions" of the delayed
// instructions
deque<MachineInstr *>::iterator OrigAdIt;
for( OrigAdIt = OrigAft.begin(); OrigAdIt != OrigAft.end() ; ++OrigAdIt ) {
DelayedAft.push_back( *OrigAdIt );
}
// empty the "added after instructions" of the original instruction
OrigAft.clear();
}
//----------------------------------------------------------------------------
// This method prints the code with registers after register allocation is
// complete.
//----------------------------------------------------------------------------
void PhyRegAlloc::printMachineCode()
{
cout << endl << ";************** Method ";
cout << Meth->getName() << " *****************" << endl;
Method::const_iterator BBI = Meth->begin(); // random iterator for BBs
for( ; BBI != Meth->end(); ++BBI) { // traverse BBs in random order
cout << endl ; printLabel( *BBI); cout << ": ";
// get the iterator for machine instructions
MachineCodeForBasicBlock& MIVec = (*BBI)->getMachineInstrVec();
MachineCodeForBasicBlock::iterator MInstIterator = MIVec.begin();
// iterate over all the machine instructions in BB
for( ; MInstIterator != MIVec.end(); ++MInstIterator) {
MachineInstr *const MInst = *MInstIterator;
cout << endl << "\t";
cout << TargetInstrDescriptors[MInst->getOpCode()].opCodeString;
//for(MachineInstr::val_op_const_iterator OpI(MInst);!OpI.done();++OpI) {
for(unsigned OpNum=0; OpNum < MInst->getNumOperands(); ++OpNum) {
MachineOperand& Op = MInst->getOperand(OpNum);
if( Op.getOperandType() == MachineOperand::MO_VirtualRegister ||
Op.getOperandType() == MachineOperand::MO_CCRegister /*||
Op.getOperandType() == MachineOperand::MO_PCRelativeDisp*/ ) {
const Value *const Val = Op.getVRegValue () ;
// ****this code is temporary till NULL Values are fixed
if( ! Val ) {
cout << "\t<*NULL*>";
continue;
}
// if a label or a constant
if( (Val->getValueType() == Value::BasicBlockVal) ) {
cout << "\t"; printLabel( Op.getVRegValue () );
}
else {
// else it must be a register value
const int RegNum = Op.getAllocatedRegNum();
cout << "\t" << "%" << MRI.getUnifiedRegName( RegNum );
}
}
else if(Op.getOperandType() == MachineOperand::MO_MachineRegister) {
cout << "\t" << "%" << MRI.getUnifiedRegName(Op.getMachineRegNum());
}
else
cout << "\t" << Op; // use dump field
}
unsigned NumOfImpRefs = MInst->getNumImplicitRefs();
if( NumOfImpRefs > 0 ) {
cout << "\tImplicit:";
for(unsigned z=0; z < NumOfImpRefs; z++) {
printValue( MInst->getImplicitRef(z) );
cout << "\t";
}
}
} // for all machine instructions
cout << endl;
} // for all BBs
cout << endl;
}
//----------------------------------------------------------------------------
//
//----------------------------------------------------------------------------
void PhyRegAlloc::colorCallRetArgs()
{
CallRetInstrListType &CallRetInstList = LRI.getCallRetInstrList();
CallRetInstrListType::const_iterator It = CallRetInstList.begin();
for( ; It != CallRetInstList.end(); ++It ) {
const MachineInstr *const CRMI = *It;
unsigned OpCode = CRMI->getOpCode();
// get the added instructions for this Call/Ret instruciton
AddedInstrns *AI = AddedInstrMap[ CRMI ];
if ( !AI ) {
AI = new AddedInstrns();
AddedInstrMap[ CRMI ] = AI;
}
// Tmp stack poistions are needed by some calls that have spilled args
// So reset it before we call each such method
mcInfo.popAllTempValues(TM);
if( (TM.getInstrInfo()).isCall( OpCode ) )
MRI.colorCallArgs( CRMI, LRI, AI, *this );
else if ( (TM.getInstrInfo()).isReturn(OpCode) )
MRI.colorRetValue( CRMI, LRI, AI );
else assert( 0 && "Non Call/Ret instrn in CallRetInstrList\n" );
}
}
//----------------------------------------------------------------------------
//----------------------------------------------------------------------------
void PhyRegAlloc::colorIncomingArgs()
{
const BasicBlock *const FirstBB = Meth->front();
const MachineInstr *FirstMI = *((FirstBB->getMachineInstrVec()).begin());
assert( FirstMI && "No machine instruction in entry BB");
AddedInstrns *AI = AddedInstrMap[ FirstMI ];
if ( !AI ) {
AI = new AddedInstrns();
AddedInstrMap[ FirstMI ] = AI;
}
MRI.colorMethodArgs(Meth, LRI, AI );
}
//----------------------------------------------------------------------------
// Used to generate a label for a basic block
//----------------------------------------------------------------------------
void PhyRegAlloc::printLabel(const Value *const Val)
{
if( Val->hasName() )
cout << Val->getName();
else
cout << "Label" << Val;
}
//----------------------------------------------------------------------------
// This method calls setSugColorUsable method of each live range. This
// will determine whether the suggested color of LR is really usable.
// A suggested color is not usable when the suggested color is volatile
// AND when there are call interferences
//----------------------------------------------------------------------------
void PhyRegAlloc::markUnusableSugColors()
{
if(DEBUG_RA ) cout << "\nmarking unusable suggested colors ..." << endl;
// hash map iterator
LiveRangeMapType::const_iterator HMI = (LRI.getLiveRangeMap())->begin();
LiveRangeMapType::const_iterator HMIEnd = (LRI.getLiveRangeMap())->end();
for( ; HMI != HMIEnd ; ++HMI ) {
if( (*HMI).first ) {
LiveRange *L = (*HMI).second; // get the LiveRange
if(L) {
if( L->hasSuggestedColor() ) {
int RCID = (L->getRegClass())->getID();
if( MRI.isRegVolatile( RCID, L->getSuggestedColor()) &&
L->isCallInterference() )
L->setSuggestedColorUsable( false );
else
L->setSuggestedColorUsable( true );
}
} // if L->hasSuggestedColor()
}
} // for all LR's in hash map
}
//----------------------------------------------------------------------------
// The following method will set the stack offsets of the live ranges that
// are decided to be spillled. This must be called just after coloring the
// LRs using the graph coloring algo. For each live range that is spilled,
// this method allocate a new spill position on the stack.
//----------------------------------------------------------------------------
void PhyRegAlloc::allocateStackSpace4SpilledLRs()
{
if(DEBUG_RA ) cout << "\nsetting LR stack offsets ..." << endl;
// hash map iterator
LiveRangeMapType::const_iterator HMI = (LRI.getLiveRangeMap())->begin();
LiveRangeMapType::const_iterator HMIEnd = (LRI.getLiveRangeMap())->end();
for( ; HMI != HMIEnd ; ++HMI ) {
if( (*HMI).first ) {
LiveRange *L = (*HMI).second; // get the LiveRange
if(L)
if( ! L->hasColor() )
L->setSpillOffFromFP(mcInfo.allocateSpilledValue(TM,L->getType()));
}
} // for all LR's in hash map
}
//----------------------------------------------------------------------------
// The entry pont to Register Allocation
//----------------------------------------------------------------------------
void PhyRegAlloc::allocateRegisters()
{
// make sure that we put all register classes into the RegClassList
// before we call constructLiveRanges (now done in the constructor of
// PhyRegAlloc class).
constructLiveRanges(); // create LR info
if( DEBUG_RA )
LRI.printLiveRanges();
createIGNodeListsAndIGs(); // create IGNode list and IGs
buildInterferenceGraphs(); // build IGs in all reg classes
if( DEBUG_RA ) {
// print all LRs in all reg classes
for( unsigned int rc=0; rc < NumOfRegClasses ; rc++)
RegClassList[ rc ]->printIGNodeList();
// print IGs in all register classes
for( unsigned int rc=0; rc < NumOfRegClasses ; rc++)
RegClassList[ rc ]->printIG();
}
LRI.coalesceLRs(); // coalesce all live ranges
// coalscing could not get rid of all phi's, add phi elimination
// instructions
// insertPhiEleminateInstrns();
if( DEBUG_RA) {
// print all LRs in all reg classes
for( unsigned int rc=0; rc < NumOfRegClasses ; rc++)
RegClassList[ rc ]->printIGNodeList();
// print IGs in all register classes
for( unsigned int rc=0; rc < NumOfRegClasses ; rc++)
RegClassList[ rc ]->printIG();
}
// mark un-usable suggested color before graph coloring algorithm.
// When this is done, the graph coloring algo will not reserve
// suggested color unnecessarily - they can be used by another LR
markUnusableSugColors();
// color all register classes using the graph coloring algo
for( unsigned int rc=0; rc < NumOfRegClasses ; rc++)
RegClassList[ rc ]->colorAllRegs();
// Atter grpah coloring, if some LRs did not receive a color (i.e, spilled)
// a poistion for such spilled LRs
allocateStackSpace4SpilledLRs();
// color incoming args and call args
colorIncomingArgs();
colorCallRetArgs();
updateMachineCode();
if (DEBUG_RA) {
MachineCodeForMethod::get(Meth).dump();
printMachineCode(); // only for DEBUGGING
}
}
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