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			283 lines
		
	
	
		
			9.8 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			283 lines
		
	
	
		
			9.8 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| //===-- llvm/CodeGen/VirtRegMap.cpp - Virtual Register Map ----------------===//
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| //
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| //                     The LLVM Compiler Infrastructure
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| //
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| // This file is distributed under the University of Illinois Open Source
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| // License. See LICENSE.TXT for details.
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| //
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| //===----------------------------------------------------------------------===//
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| //
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| // This file implements the VirtRegMap class.
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| //
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| // It also contains implementations of the the Spiller interface, which, given a
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| // virtual register map and a machine function, eliminates all virtual
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| // references by replacing them with physical register references - adding spill
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| // code as necessary.
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| //
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| //===----------------------------------------------------------------------===//
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| 
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| #define DEBUG_TYPE "virtregmap"
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| #include "VirtRegMap.h"
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| #include "llvm/Function.h"
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| #include "llvm/CodeGen/LiveIntervalAnalysis.h"
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| #include "llvm/CodeGen/MachineFrameInfo.h"
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| #include "llvm/CodeGen/MachineFunction.h"
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| #include "llvm/CodeGen/MachineInstrBuilder.h"
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| #include "llvm/CodeGen/MachineRegisterInfo.h"
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| #include "llvm/Target/TargetMachine.h"
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| #include "llvm/Target/TargetInstrInfo.h"
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| #include "llvm/Target/TargetRegisterInfo.h"
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| #include "llvm/Support/CommandLine.h"
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| #include "llvm/Support/Compiler.h"
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| #include "llvm/Support/Debug.h"
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| #include "llvm/Support/raw_ostream.h"
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| #include "llvm/ADT/BitVector.h"
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| #include "llvm/ADT/DenseMap.h"
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| #include "llvm/ADT/DepthFirstIterator.h"
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| #include "llvm/ADT/Statistic.h"
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| #include "llvm/ADT/STLExtras.h"
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| #include "llvm/ADT/SmallSet.h"
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| #include <algorithm>
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| using namespace llvm;
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| 
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| STATISTIC(NumSpills  , "Number of register spills");
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| 
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| //===----------------------------------------------------------------------===//
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| //  VirtRegMap implementation
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| //===----------------------------------------------------------------------===//
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| 
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| char VirtRegMap::ID = 0;
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| 
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| static RegisterPass<VirtRegMap>
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| X("virtregmap", "Virtual Register Map");
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| 
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| bool VirtRegMap::runOnMachineFunction(MachineFunction &mf) {
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|   MRI = &mf.getRegInfo();
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|   TII = mf.getTarget().getInstrInfo();
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|   TRI = mf.getTarget().getRegisterInfo();
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|   MF = &mf;
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|   
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|   ReMatId = MAX_STACK_SLOT+1;
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|   LowSpillSlot = HighSpillSlot = NO_STACK_SLOT;
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|   
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|   Virt2PhysMap.clear();
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|   Virt2StackSlotMap.clear();
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|   Virt2ReMatIdMap.clear();
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|   Virt2SplitMap.clear();
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|   Virt2SplitKillMap.clear();
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|   ReMatMap.clear();
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|   ImplicitDefed.clear();
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|   SpillSlotToUsesMap.clear();
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|   MI2VirtMap.clear();
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|   SpillPt2VirtMap.clear();
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|   RestorePt2VirtMap.clear();
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|   EmergencySpillMap.clear();
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|   EmergencySpillSlots.clear();
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|   
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|   SpillSlotToUsesMap.resize(8);
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|   ImplicitDefed.resize(MF->getRegInfo().getLastVirtReg()+1-
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|                        TargetRegisterInfo::FirstVirtualRegister);
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| 
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|   allocatableRCRegs.clear();
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|   for (TargetRegisterInfo::regclass_iterator I = TRI->regclass_begin(),
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|          E = TRI->regclass_end(); I != E; ++I)
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|     allocatableRCRegs.insert(std::make_pair(*I,
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|                                             TRI->getAllocatableSet(mf, *I)));
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| 
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|   grow();
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|   
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|   return false;
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| }
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| 
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| void VirtRegMap::grow() {
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|   unsigned LastVirtReg = MF->getRegInfo().getLastVirtReg();
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|   Virt2PhysMap.grow(LastVirtReg);
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|   Virt2StackSlotMap.grow(LastVirtReg);
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|   Virt2ReMatIdMap.grow(LastVirtReg);
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|   Virt2SplitMap.grow(LastVirtReg);
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|   Virt2SplitKillMap.grow(LastVirtReg);
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|   ReMatMap.grow(LastVirtReg);
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|   ImplicitDefed.resize(LastVirtReg-TargetRegisterInfo::FirstVirtualRegister+1);
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| }
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| 
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| unsigned VirtRegMap::getRegAllocPref(unsigned virtReg) {
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|   std::pair<unsigned, unsigned> Hint = MRI->getRegAllocationHint(virtReg);
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|   unsigned physReg = Hint.second;
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|   if (physReg &&
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|       TargetRegisterInfo::isVirtualRegister(physReg) && hasPhys(physReg))
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|     physReg = getPhys(physReg);
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|   if (Hint.first == 0)
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|     return (physReg && TargetRegisterInfo::isPhysicalRegister(physReg))
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|       ? physReg : 0;
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|   return TRI->ResolveRegAllocHint(Hint.first, physReg, *MF);
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| }
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| 
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| int VirtRegMap::assignVirt2StackSlot(unsigned virtReg) {
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|   assert(TargetRegisterInfo::isVirtualRegister(virtReg));
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|   assert(Virt2StackSlotMap[virtReg] == NO_STACK_SLOT &&
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|          "attempt to assign stack slot to already spilled register");
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|   const TargetRegisterClass* RC = MF->getRegInfo().getRegClass(virtReg);
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|   int SS = MF->getFrameInfo()->CreateStackObject(RC->getSize(),
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|                                                 RC->getAlignment());
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|   if (LowSpillSlot == NO_STACK_SLOT)
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|     LowSpillSlot = SS;
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|   if (HighSpillSlot == NO_STACK_SLOT || SS > HighSpillSlot)
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|     HighSpillSlot = SS;
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|   unsigned Idx = SS-LowSpillSlot;
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|   while (Idx >= SpillSlotToUsesMap.size())
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|     SpillSlotToUsesMap.resize(SpillSlotToUsesMap.size()*2);
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|   Virt2StackSlotMap[virtReg] = SS;
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|   ++NumSpills;
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|   return SS;
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| }
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| 
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| void VirtRegMap::assignVirt2StackSlot(unsigned virtReg, int SS) {
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|   assert(TargetRegisterInfo::isVirtualRegister(virtReg));
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|   assert(Virt2StackSlotMap[virtReg] == NO_STACK_SLOT &&
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|          "attempt to assign stack slot to already spilled register");
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|   assert((SS >= 0 ||
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|           (SS >= MF->getFrameInfo()->getObjectIndexBegin())) &&
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|          "illegal fixed frame index");
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|   Virt2StackSlotMap[virtReg] = SS;
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| }
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| 
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| int VirtRegMap::assignVirtReMatId(unsigned virtReg) {
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|   assert(TargetRegisterInfo::isVirtualRegister(virtReg));
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|   assert(Virt2ReMatIdMap[virtReg] == NO_STACK_SLOT &&
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|          "attempt to assign re-mat id to already spilled register");
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|   Virt2ReMatIdMap[virtReg] = ReMatId;
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|   return ReMatId++;
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| }
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| 
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| void VirtRegMap::assignVirtReMatId(unsigned virtReg, int id) {
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|   assert(TargetRegisterInfo::isVirtualRegister(virtReg));
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|   assert(Virt2ReMatIdMap[virtReg] == NO_STACK_SLOT &&
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|          "attempt to assign re-mat id to already spilled register");
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|   Virt2ReMatIdMap[virtReg] = id;
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| }
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| 
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| int VirtRegMap::getEmergencySpillSlot(const TargetRegisterClass *RC) {
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|   std::map<const TargetRegisterClass*, int>::iterator I =
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|     EmergencySpillSlots.find(RC);
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|   if (I != EmergencySpillSlots.end())
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|     return I->second;
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|   int SS = MF->getFrameInfo()->CreateStackObject(RC->getSize(),
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|                                                 RC->getAlignment());
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|   if (LowSpillSlot == NO_STACK_SLOT)
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|     LowSpillSlot = SS;
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|   if (HighSpillSlot == NO_STACK_SLOT || SS > HighSpillSlot)
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|     HighSpillSlot = SS;
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|   EmergencySpillSlots[RC] = SS;
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|   return SS;
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| }
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| 
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| void VirtRegMap::addSpillSlotUse(int FI, MachineInstr *MI) {
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|   if (!MF->getFrameInfo()->isFixedObjectIndex(FI)) {
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|     // If FI < LowSpillSlot, this stack reference was produced by
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|     // instruction selection and is not a spill
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|     if (FI >= LowSpillSlot) {
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|       assert(FI >= 0 && "Spill slot index should not be negative!");
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|       assert((unsigned)FI-LowSpillSlot < SpillSlotToUsesMap.size()
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|              && "Invalid spill slot");
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|       SpillSlotToUsesMap[FI-LowSpillSlot].insert(MI);
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|     }
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|   }
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| }
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| 
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| void VirtRegMap::virtFolded(unsigned VirtReg, MachineInstr *OldMI,
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|                             MachineInstr *NewMI, ModRef MRInfo) {
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|   // Move previous memory references folded to new instruction.
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|   MI2VirtMapTy::iterator IP = MI2VirtMap.lower_bound(NewMI);
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|   for (MI2VirtMapTy::iterator I = MI2VirtMap.lower_bound(OldMI),
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|          E = MI2VirtMap.end(); I != E && I->first == OldMI; ) {
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|     MI2VirtMap.insert(IP, std::make_pair(NewMI, I->second));
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|     MI2VirtMap.erase(I++);
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|   }
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| 
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|   // add new memory reference
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|   MI2VirtMap.insert(IP, std::make_pair(NewMI, std::make_pair(VirtReg, MRInfo)));
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| }
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| 
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| void VirtRegMap::virtFolded(unsigned VirtReg, MachineInstr *MI, ModRef MRInfo) {
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|   MI2VirtMapTy::iterator IP = MI2VirtMap.lower_bound(MI);
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|   MI2VirtMap.insert(IP, std::make_pair(MI, std::make_pair(VirtReg, MRInfo)));
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| }
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| 
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| void VirtRegMap::RemoveMachineInstrFromMaps(MachineInstr *MI) {
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|   for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
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|     MachineOperand &MO = MI->getOperand(i);
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|     if (!MO.isFI())
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|       continue;
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|     int FI = MO.getIndex();
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|     if (MF->getFrameInfo()->isFixedObjectIndex(FI))
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|       continue;
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|     // This stack reference was produced by instruction selection and
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|     // is not a spill
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|     if (FI < LowSpillSlot)
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|       continue;
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|     assert((unsigned)FI-LowSpillSlot < SpillSlotToUsesMap.size()
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|            && "Invalid spill slot");
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|     SpillSlotToUsesMap[FI-LowSpillSlot].erase(MI);
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|   }
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|   MI2VirtMap.erase(MI);
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|   SpillPt2VirtMap.erase(MI);
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|   RestorePt2VirtMap.erase(MI);
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|   EmergencySpillMap.erase(MI);
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| }
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| 
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| /// FindUnusedRegisters - Gather a list of allocatable registers that
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| /// have not been allocated to any virtual register.
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| bool VirtRegMap::FindUnusedRegisters(LiveIntervals* LIs) {
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|   unsigned NumRegs = TRI->getNumRegs();
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|   UnusedRegs.reset();
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|   UnusedRegs.resize(NumRegs);
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| 
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|   BitVector Used(NumRegs);
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|   for (unsigned i = TargetRegisterInfo::FirstVirtualRegister,
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|          e = MF->getRegInfo().getLastVirtReg(); i <= e; ++i)
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|     if (Virt2PhysMap[i] != (unsigned)VirtRegMap::NO_PHYS_REG)
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|       Used.set(Virt2PhysMap[i]);
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| 
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|   BitVector Allocatable = TRI->getAllocatableSet(*MF);
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|   bool AnyUnused = false;
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|   for (unsigned Reg = 1; Reg < NumRegs; ++Reg) {
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|     if (Allocatable[Reg] && !Used[Reg] && !LIs->hasInterval(Reg)) {
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|       bool ReallyUnused = true;
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|       for (const unsigned *AS = TRI->getAliasSet(Reg); *AS; ++AS) {
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|         if (Used[*AS] || LIs->hasInterval(*AS)) {
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|           ReallyUnused = false;
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|           break;
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|         }
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|       }
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|       if (ReallyUnused) {
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|         AnyUnused = true;
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|         UnusedRegs.set(Reg);
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|       }
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|     }
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|   }
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| 
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|   return AnyUnused;
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| }
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| 
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| void VirtRegMap::print(raw_ostream &OS, const Module* M) const {
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|   const TargetRegisterInfo* TRI = MF->getTarget().getRegisterInfo();
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| 
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|   OS << "********** REGISTER MAP **********\n";
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|   for (unsigned i = TargetRegisterInfo::FirstVirtualRegister,
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|          e = MF->getRegInfo().getLastVirtReg(); i <= e; ++i) {
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|     if (Virt2PhysMap[i] != (unsigned)VirtRegMap::NO_PHYS_REG)
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|       OS << "[reg" << i << " -> " << TRI->getName(Virt2PhysMap[i])
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|          << "]\n";
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|   }
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| 
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|   for (unsigned i = TargetRegisterInfo::FirstVirtualRegister,
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|          e = MF->getRegInfo().getLastVirtReg(); i <= e; ++i)
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|     if (Virt2StackSlotMap[i] != VirtRegMap::NO_STACK_SLOT)
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|       OS << "[reg" << i << " -> fi#" << Virt2StackSlotMap[i] << "]\n";
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|   OS << '\n';
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| }
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| 
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| void VirtRegMap::dump() const {
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|   print(errs());
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| }
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