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//===-- llvm/CodeGen/VirtRegMap.h - Virtual Register Map -*- C++ -*--------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements a virtual register map. This maps virtual registers to
// physical registers and virtual registers to stack slots. It is created and
// updated by a register allocator and then used by a machine code rewriter that
// adds spill code and rewrites virtual into physical register references.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_VIRTREGMAP_H
#define LLVM_CODEGEN_VIRTREGMAP_H
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/IndexedMap.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/Streams.h"
#include <map>
namespace llvm {
class LiveIntervals;
class MachineInstr;
class MachineFunction;
class TargetInstrInfo;
class VirtRegMap : public MachineFunctionPass {
public:
enum {
NO_PHYS_REG = 0,
NO_STACK_SLOT = (1L << 30)-1,
MAX_STACK_SLOT = (1L << 18)-1
};
enum ModRef { isRef = 1, isMod = 2, isModRef = 3 };
typedef std::multimap<MachineInstr*,
std::pair<unsigned, ModRef> > MI2VirtMapTy;
private:
const TargetInstrInfo *TII;
MachineFunction *MF;
/// Virt2PhysMap - This is a virtual to physical register
/// mapping. Each virtual register is required to have an entry in
/// it; even spilled virtual registers (the register mapped to a
/// spilled register is the temporary used to load it from the
/// stack).
IndexedMap<unsigned, VirtReg2IndexFunctor> Virt2PhysMap;
/// Virt2StackSlotMap - This is virtual register to stack slot
/// mapping. Each spilled virtual register has an entry in it
/// which corresponds to the stack slot this register is spilled
/// at.
IndexedMap<int, VirtReg2IndexFunctor> Virt2StackSlotMap;
/// Virt2ReMatIdMap - This is virtual register to rematerialization id
/// mapping. Each spilled virtual register that should be remat'd has an
/// entry in it which corresponds to the remat id.
IndexedMap<int, VirtReg2IndexFunctor> Virt2ReMatIdMap;
/// Virt2SplitMap - This is virtual register to splitted virtual register
/// mapping.
IndexedMap<unsigned, VirtReg2IndexFunctor> Virt2SplitMap;
/// Virt2SplitKillMap - This is splitted virtual register to its last use
/// (kill) index mapping.
IndexedMap<unsigned> Virt2SplitKillMap;
/// ReMatMap - This is virtual register to re-materialized instruction
/// mapping. Each virtual register whose definition is going to be
/// re-materialized has an entry in it.
IndexedMap<MachineInstr*, VirtReg2IndexFunctor> ReMatMap;
/// MI2VirtMap - This is MachineInstr to virtual register
/// mapping. In the case of memory spill code being folded into
/// instructions, we need to know which virtual register was
/// read/written by this instruction.
MI2VirtMapTy MI2VirtMap;
/// SpillPt2VirtMap - This records the virtual registers which should
/// be spilled right after the MachineInstr due to live interval
/// splitting.
std::map<MachineInstr*, std::vector<std::pair<unsigned,bool> > >
SpillPt2VirtMap;
/// RestorePt2VirtMap - This records the virtual registers which should
/// be restored right before the MachineInstr due to live interval
/// splitting.
std::map<MachineInstr*, std::vector<unsigned> > RestorePt2VirtMap;
/// EmergencySpillMap - This records the physical registers that should
/// be spilled / restored around the MachineInstr since the register
/// allocator has run out of registers.
std::map<MachineInstr*, std::vector<unsigned> > EmergencySpillMap;
/// EmergencySpillSlots - This records emergency spill slots used to
/// spill physical registers when the register allocator runs out of
/// registers. Ideally only one stack slot is used per function per
/// register class.
std::map<const TargetRegisterClass*, int> EmergencySpillSlots;
/// ReMatId - Instead of assigning a stack slot to a to be rematerialized
/// virtual register, an unique id is being assigned. This keeps track of
/// the highest id used so far. Note, this starts at (1<<18) to avoid
/// conflicts with stack slot numbers.
int ReMatId;
/// LowSpillSlot, HighSpillSlot - Lowest and highest spill slot indexes.
int LowSpillSlot, HighSpillSlot;
/// SpillSlotToUsesMap - Records uses for each register spill slot.
SmallVector<SmallPtrSet<MachineInstr*, 4>, 8> SpillSlotToUsesMap;
/// ImplicitDefed - One bit for each virtual register. If set it indicates
/// the register is implicitly defined.
BitVector ImplicitDefed;
/// UnusedRegs - A list of physical registers that have not been used.
BitVector UnusedRegs;
VirtRegMap(const VirtRegMap&); // DO NOT IMPLEMENT
void operator=(const VirtRegMap&); // DO NOT IMPLEMENT
public:
static char ID;
VirtRegMap() : MachineFunctionPass(&ID), Virt2PhysMap(NO_PHYS_REG),
Virt2StackSlotMap(NO_STACK_SLOT),
Virt2ReMatIdMap(NO_STACK_SLOT), Virt2SplitMap(0),
Virt2SplitKillMap(0), ReMatMap(NULL),
ReMatId(MAX_STACK_SLOT+1),
LowSpillSlot(NO_STACK_SLOT), HighSpillSlot(NO_STACK_SLOT) { }
virtual bool runOnMachineFunction(MachineFunction &MF);
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
MachineFunctionPass::getAnalysisUsage(AU);
}
void grow();
/// @brief returns true if the specified virtual register is
/// mapped to a physical register
bool hasPhys(unsigned virtReg) const {
return getPhys(virtReg) != NO_PHYS_REG;
}
/// @brief returns the physical register mapped to the specified
/// virtual register
unsigned getPhys(unsigned virtReg) const {
assert(TargetRegisterInfo::isVirtualRegister(virtReg));
return Virt2PhysMap[virtReg];
}
/// @brief creates a mapping for the specified virtual register to
/// the specified physical register
void assignVirt2Phys(unsigned virtReg, unsigned physReg) {
assert(TargetRegisterInfo::isVirtualRegister(virtReg) &&
TargetRegisterInfo::isPhysicalRegister(physReg));
assert(Virt2PhysMap[virtReg] == NO_PHYS_REG &&
"attempt to assign physical register to already mapped "
"virtual register");
Virt2PhysMap[virtReg] = physReg;
}
/// @brief clears the specified virtual register's, physical
/// register mapping
void clearVirt(unsigned virtReg) {
assert(TargetRegisterInfo::isVirtualRegister(virtReg));
assert(Virt2PhysMap[virtReg] != NO_PHYS_REG &&
"attempt to clear a not assigned virtual register");
Virt2PhysMap[virtReg] = NO_PHYS_REG;
}
/// @brief clears all virtual to physical register mappings
void clearAllVirt() {
Virt2PhysMap.clear();
grow();
}
/// @brief records virtReg is a split live interval from SReg.
void setIsSplitFromReg(unsigned virtReg, unsigned SReg) {
Virt2SplitMap[virtReg] = SReg;
}
/// @brief returns the live interval virtReg is split from.
unsigned getPreSplitReg(unsigned virtReg) {
return Virt2SplitMap[virtReg];
}
/// @brief returns true if the specified virtual register is not
/// mapped to a stack slot or rematerialized.
bool isAssignedReg(unsigned virtReg) const {
if (getStackSlot(virtReg) == NO_STACK_SLOT &&
getReMatId(virtReg) == NO_STACK_SLOT)
return true;
// Split register can be assigned a physical register as well as a
// stack slot or remat id.
return (Virt2SplitMap[virtReg] && Virt2PhysMap[virtReg] != NO_PHYS_REG);
}
/// @brief returns the stack slot mapped to the specified virtual
/// register
int getStackSlot(unsigned virtReg) const {
assert(TargetRegisterInfo::isVirtualRegister(virtReg));
return Virt2StackSlotMap[virtReg];
}
/// @brief returns the rematerialization id mapped to the specified virtual
/// register
int getReMatId(unsigned virtReg) const {
assert(TargetRegisterInfo::isVirtualRegister(virtReg));
return Virt2ReMatIdMap[virtReg];
}
/// @brief create a mapping for the specifed virtual register to
/// the next available stack slot
int assignVirt2StackSlot(unsigned virtReg);
/// @brief create a mapping for the specified virtual register to
/// the specified stack slot
void assignVirt2StackSlot(unsigned virtReg, int frameIndex);
/// @brief assign an unique re-materialization id to the specified
/// virtual register.
int assignVirtReMatId(unsigned virtReg);
/// @brief assign an unique re-materialization id to the specified
/// virtual register.
void assignVirtReMatId(unsigned virtReg, int id);
/// @brief returns true if the specified virtual register is being
/// re-materialized.
bool isReMaterialized(unsigned virtReg) const {
return ReMatMap[virtReg] != NULL;
}
/// @brief returns the original machine instruction being re-issued
/// to re-materialize the specified virtual register.
MachineInstr *getReMaterializedMI(unsigned virtReg) const {
return ReMatMap[virtReg];
}
/// @brief records the specified virtual register will be
/// re-materialized and the original instruction which will be re-issed
/// for this purpose. If parameter all is true, then all uses of the
/// registers are rematerialized and it's safe to delete the definition.
void setVirtIsReMaterialized(unsigned virtReg, MachineInstr *def) {
ReMatMap[virtReg] = def;
}
/// @brief record the last use (kill) of a split virtual register.
void addKillPoint(unsigned virtReg, unsigned index) {
Virt2SplitKillMap[virtReg] = index;
}
unsigned getKillPoint(unsigned virtReg) const {
return Virt2SplitKillMap[virtReg];
}
/// @brief remove the last use (kill) of a split virtual register.
void removeKillPoint(unsigned virtReg) {
Virt2SplitKillMap[virtReg] = 0;
}
/// @brief returns true if the specified MachineInstr is a spill point.
bool isSpillPt(MachineInstr *Pt) const {
return SpillPt2VirtMap.find(Pt) != SpillPt2VirtMap.end();
}
/// @brief returns the virtual registers that should be spilled due to
/// splitting right after the specified MachineInstr.
std::vector<std::pair<unsigned,bool> > &getSpillPtSpills(MachineInstr *Pt) {
return SpillPt2VirtMap[Pt];
}
/// @brief records the specified MachineInstr as a spill point for virtReg.
void addSpillPoint(unsigned virtReg, bool isKill, MachineInstr *Pt) {
std::map<MachineInstr*, std::vector<std::pair<unsigned,bool> > >::iterator
I = SpillPt2VirtMap.find(Pt);
if (I != SpillPt2VirtMap.end())
I->second.push_back(std::make_pair(virtReg, isKill));
else {
std::vector<std::pair<unsigned,bool> > Virts;
Virts.push_back(std::make_pair(virtReg, isKill));
SpillPt2VirtMap.insert(std::make_pair(Pt, Virts));
}
}
/// @brief - transfer spill point information from one instruction to
/// another.
void transferSpillPts(MachineInstr *Old, MachineInstr *New) {
std::map<MachineInstr*, std::vector<std::pair<unsigned,bool> > >::iterator
I = SpillPt2VirtMap.find(Old);
if (I == SpillPt2VirtMap.end())
return;
while (!I->second.empty()) {
unsigned virtReg = I->second.back().first;
bool isKill = I->second.back().second;
I->second.pop_back();
addSpillPoint(virtReg, isKill, New);
}
SpillPt2VirtMap.erase(I);
}
/// @brief returns true if the specified MachineInstr is a restore point.
bool isRestorePt(MachineInstr *Pt) const {
return RestorePt2VirtMap.find(Pt) != RestorePt2VirtMap.end();
}
/// @brief returns the virtual registers that should be restoreed due to
/// splitting right after the specified MachineInstr.
std::vector<unsigned> &getRestorePtRestores(MachineInstr *Pt) {
return RestorePt2VirtMap[Pt];
}
/// @brief records the specified MachineInstr as a restore point for virtReg.
void addRestorePoint(unsigned virtReg, MachineInstr *Pt) {
std::map<MachineInstr*, std::vector<unsigned> >::iterator I =
RestorePt2VirtMap.find(Pt);
if (I != RestorePt2VirtMap.end())
I->second.push_back(virtReg);
else {
std::vector<unsigned> Virts;
Virts.push_back(virtReg);
RestorePt2VirtMap.insert(std::make_pair(Pt, Virts));
}
}
/// @brief - transfer restore point information from one instruction to
/// another.
void transferRestorePts(MachineInstr *Old, MachineInstr *New) {
std::map<MachineInstr*, std::vector<unsigned> >::iterator I =
RestorePt2VirtMap.find(Old);
if (I == RestorePt2VirtMap.end())
return;
while (!I->second.empty()) {
unsigned virtReg = I->second.back();
I->second.pop_back();
addRestorePoint(virtReg, New);
}
RestorePt2VirtMap.erase(I);
}
/// @brief records that the specified physical register must be spilled
/// around the specified machine instr.
void addEmergencySpill(unsigned PhysReg, MachineInstr *MI) {
if (EmergencySpillMap.find(MI) != EmergencySpillMap.end())
EmergencySpillMap[MI].push_back(PhysReg);
else {
std::vector<unsigned> PhysRegs;
PhysRegs.push_back(PhysReg);
EmergencySpillMap.insert(std::make_pair(MI, PhysRegs));
}
}
/// @brief returns true if one or more physical registers must be spilled
/// around the specified instruction.
bool hasEmergencySpills(MachineInstr *MI) const {
return EmergencySpillMap.find(MI) != EmergencySpillMap.end();
}
/// @brief returns the physical registers to be spilled and restored around
/// the instruction.
std::vector<unsigned> &getEmergencySpills(MachineInstr *MI) {
return EmergencySpillMap[MI];
}
/// @brief - transfer emergency spill information from one instruction to
/// another.
void transferEmergencySpills(MachineInstr *Old, MachineInstr *New) {
std::map<MachineInstr*,std::vector<unsigned> >::iterator I =
EmergencySpillMap.find(Old);
if (I == EmergencySpillMap.end())
return;
while (!I->second.empty()) {
unsigned virtReg = I->second.back();
I->second.pop_back();
addEmergencySpill(virtReg, New);
}
EmergencySpillMap.erase(I);
}
/// @brief return or get a emergency spill slot for the register class.
int getEmergencySpillSlot(const TargetRegisterClass *RC);
/// @brief Return lowest spill slot index.
int getLowSpillSlot() const {
return LowSpillSlot;
}
/// @brief Return highest spill slot index.
int getHighSpillSlot() const {
return HighSpillSlot;
}
/// @brief Records a spill slot use.
void addSpillSlotUse(int FrameIndex, MachineInstr *MI);
/// @brief Returns true if spill slot has been used.
bool isSpillSlotUsed(int FrameIndex) const {
assert(FrameIndex >= 0 && "Spill slot index should not be negative!");
return !SpillSlotToUsesMap[FrameIndex-LowSpillSlot].empty();
}
/// @brief Mark the specified register as being implicitly defined.
void setIsImplicitlyDefined(unsigned VirtReg) {
ImplicitDefed.set(VirtReg-TargetRegisterInfo::FirstVirtualRegister);
}
/// @brief Returns true if the virtual register is implicitly defined.
bool isImplicitlyDefined(unsigned VirtReg) const {
return ImplicitDefed[VirtReg-TargetRegisterInfo::FirstVirtualRegister];
}
/// @brief Updates information about the specified virtual register's value
/// folded into newMI machine instruction.
void virtFolded(unsigned VirtReg, MachineInstr *OldMI, MachineInstr *NewMI,
ModRef MRInfo);
/// @brief Updates information about the specified virtual register's value
/// folded into the specified machine instruction.
void virtFolded(unsigned VirtReg, MachineInstr *MI, ModRef MRInfo);
/// @brief returns the virtual registers' values folded in memory
/// operands of this instruction
std::pair<MI2VirtMapTy::const_iterator, MI2VirtMapTy::const_iterator>
getFoldedVirts(MachineInstr* MI) const {
return MI2VirtMap.equal_range(MI);
}
/// RemoveMachineInstrFromMaps - MI is being erased, remove it from the
/// the folded instruction map and spill point map.
void RemoveMachineInstrFromMaps(MachineInstr *MI);
/// FindUnusedRegisters - Gather a list of allocatable registers that
/// have not been allocated to any virtual register.
bool FindUnusedRegisters(const TargetRegisterInfo *TRI,
LiveIntervals* LIs);
/// HasUnusedRegisters - Return true if there are any allocatable registers
/// that have not been allocated to any virtual register.
bool HasUnusedRegisters() const {
return !UnusedRegs.none();
}
/// setRegisterUsed - Remember the physical register is now used.
void setRegisterUsed(unsigned Reg) {
UnusedRegs.reset(Reg);
}
/// isRegisterUnused - Return true if the physical register has not been
/// used.
bool isRegisterUnused(unsigned Reg) const {
return UnusedRegs[Reg];
}
/// getFirstUnusedRegister - Return the first physical register that has not
/// been used.
unsigned getFirstUnusedRegister(const TargetRegisterClass *RC) {
int Reg = UnusedRegs.find_first();
while (Reg != -1) {
if (RC->contains(Reg))
return (unsigned)Reg;
Reg = UnusedRegs.find_next(Reg);
}
return 0;
}
void print(std::ostream &OS, const Module* M = 0) const;
void print(std::ostream *OS) const { if (OS) print(*OS); }
void dump() const;
};
inline std::ostream *operator<<(std::ostream *OS, const VirtRegMap &VRM) {
VRM.print(OS);
return OS;
}
inline std::ostream &operator<<(std::ostream &OS, const VirtRegMap &VRM) {
VRM.print(OS);
return OS;
}
} // End llvm namespace
#endif
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