llvm-6502/include/llvm/CodeGen/LiveIntervalAnalysis.h
Owen Anderson 6b098dee28 Remember which MachineOperand we were processing, so we don't have to scan the list to find it again later.
This speeds up live intervals from 0.37s to 0.30s on instcombine.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52745 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-25 23:39:39 +00:00

458 lines
18 KiB
C++

//===-- LiveIntervalAnalysis.h - Live Interval Analysis ---------*- 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 the LiveInterval analysis pass. Given some numbering of
// each the machine instructions (in this implemention depth-first order) an
// interval [i, j) is said to be a live interval for register v if there is no
// instruction with number j' > j such that v is live at j' and there is no
// instruction with number i' < i such that v is live at i'. In this
// implementation intervals can have holes, i.e. an interval might look like
// [1,20), [50,65), [1000,1001).
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_LIVEINTERVAL_ANALYSIS_H
#define LLVM_CODEGEN_LIVEINTERVAL_ANALYSIS_H
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/LiveInterval.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/Allocator.h"
#include <cmath>
#include <map>
namespace llvm {
class LiveVariables;
class MachineLoopInfo;
class TargetRegisterInfo;
class MachineRegisterInfo;
class TargetInstrInfo;
class TargetRegisterClass;
class VirtRegMap;
typedef std::pair<unsigned, MachineBasicBlock*> IdxMBBPair;
inline bool operator<(unsigned V, const IdxMBBPair &IM) {
return V < IM.first;
}
inline bool operator<(const IdxMBBPair &IM, unsigned V) {
return IM.first < V;
}
struct Idx2MBBCompare {
bool operator()(const IdxMBBPair &LHS, const IdxMBBPair &RHS) const {
return LHS.first < RHS.first;
}
};
class LiveIntervals : public MachineFunctionPass {
MachineFunction* mf_;
MachineRegisterInfo* mri_;
const TargetMachine* tm_;
const TargetRegisterInfo* tri_;
const TargetInstrInfo* tii_;
LiveVariables* lv_;
/// Special pool allocator for VNInfo's (LiveInterval val#).
///
BumpPtrAllocator VNInfoAllocator;
/// MBB2IdxMap - The indexes of the first and last instructions in the
/// specified basic block.
std::vector<std::pair<unsigned, unsigned> > MBB2IdxMap;
/// Idx2MBBMap - Sorted list of pairs of index of first instruction
/// and MBB id.
std::vector<IdxMBBPair> Idx2MBBMap;
typedef std::map<MachineInstr*, unsigned> Mi2IndexMap;
Mi2IndexMap mi2iMap_;
typedef std::vector<MachineInstr*> Index2MiMap;
Index2MiMap i2miMap_;
typedef std::map<unsigned, LiveInterval> Reg2IntervalMap;
Reg2IntervalMap r2iMap_;
BitVector allocatableRegs_;
std::vector<MachineInstr*> ClonedMIs;
public:
static char ID; // Pass identification, replacement for typeid
LiveIntervals() : MachineFunctionPass((intptr_t)&ID) {}
struct InstrSlots {
enum {
LOAD = 0,
USE = 1,
DEF = 2,
STORE = 3,
NUM = 4
};
};
static unsigned getBaseIndex(unsigned index) {
return index - (index % InstrSlots::NUM);
}
static unsigned getBoundaryIndex(unsigned index) {
return getBaseIndex(index + InstrSlots::NUM - 1);
}
static unsigned getLoadIndex(unsigned index) {
return getBaseIndex(index) + InstrSlots::LOAD;
}
static unsigned getUseIndex(unsigned index) {
return getBaseIndex(index) + InstrSlots::USE;
}
static unsigned getDefIndex(unsigned index) {
return getBaseIndex(index) + InstrSlots::DEF;
}
static unsigned getStoreIndex(unsigned index) {
return getBaseIndex(index) + InstrSlots::STORE;
}
static float getSpillWeight(bool isDef, bool isUse, unsigned loopDepth) {
return (isDef + isUse) * powf(10.0F, (float)loopDepth);
}
typedef Reg2IntervalMap::iterator iterator;
typedef Reg2IntervalMap::const_iterator const_iterator;
const_iterator begin() const { return r2iMap_.begin(); }
const_iterator end() const { return r2iMap_.end(); }
iterator begin() { return r2iMap_.begin(); }
iterator end() { return r2iMap_.end(); }
unsigned getNumIntervals() const { return (unsigned)r2iMap_.size(); }
LiveInterval &getInterval(unsigned reg) {
Reg2IntervalMap::iterator I = r2iMap_.find(reg);
assert(I != r2iMap_.end() && "Interval does not exist for register");
return I->second;
}
const LiveInterval &getInterval(unsigned reg) const {
Reg2IntervalMap::const_iterator I = r2iMap_.find(reg);
assert(I != r2iMap_.end() && "Interval does not exist for register");
return I->second;
}
bool hasInterval(unsigned reg) const {
return r2iMap_.count(reg);
}
/// getMBBStartIdx - Return the base index of the first instruction in the
/// specified MachineBasicBlock.
unsigned getMBBStartIdx(MachineBasicBlock *MBB) const {
return getMBBStartIdx(MBB->getNumber());
}
unsigned getMBBStartIdx(unsigned MBBNo) const {
assert(MBBNo < MBB2IdxMap.size() && "Invalid MBB number!");
return MBB2IdxMap[MBBNo].first;
}
/// getMBBEndIdx - Return the store index of the last instruction in the
/// specified MachineBasicBlock.
unsigned getMBBEndIdx(MachineBasicBlock *MBB) const {
return getMBBEndIdx(MBB->getNumber());
}
unsigned getMBBEndIdx(unsigned MBBNo) const {
assert(MBBNo < MBB2IdxMap.size() && "Invalid MBB number!");
return MBB2IdxMap[MBBNo].second;
}
/// getIntervalSize - get the size of an interval in "units,"
/// where every function is composed of one thousand units. This
/// measure scales properly with empty index slots in the function.
unsigned getScaledIntervalSize(LiveInterval& I) const {
return (1000 / InstrSlots::NUM * I.getSize()) / i2miMap_.size();
}
/// getMBBFromIndex - given an index in any instruction of an
/// MBB return a pointer the MBB
MachineBasicBlock* getMBBFromIndex(unsigned index) const {
std::vector<IdxMBBPair>::const_iterator I =
std::lower_bound(Idx2MBBMap.begin(), Idx2MBBMap.end(), index);
// Take the pair containing the index
std::vector<IdxMBBPair>::const_iterator J =
((I != Idx2MBBMap.end() && I->first > index) ||
(I == Idx2MBBMap.end() && Idx2MBBMap.size()>0)) ? (I-1): I;
assert(J != Idx2MBBMap.end() && J->first < index+1 &&
index <= getMBBEndIdx(J->second) &&
"index does not correspond to an MBB");
return J->second;
}
/// getInstructionIndex - returns the base index of instr
unsigned getInstructionIndex(MachineInstr* instr) const {
Mi2IndexMap::const_iterator it = mi2iMap_.find(instr);
assert(it != mi2iMap_.end() && "Invalid instruction!");
return it->second;
}
/// getInstructionFromIndex - given an index in any slot of an
/// instruction return a pointer the instruction
MachineInstr* getInstructionFromIndex(unsigned index) const {
index /= InstrSlots::NUM; // convert index to vector index
assert(index < i2miMap_.size() &&
"index does not correspond to an instruction");
return i2miMap_[index];
}
/// conflictsWithPhysRegDef - Returns true if the specified register
/// is defined during the duration of the specified interval.
bool conflictsWithPhysRegDef(const LiveInterval &li, VirtRegMap &vrm,
unsigned reg);
/// findLiveInMBBs - Given a live range, if the value of the range
/// is live in any MBB returns true as well as the list of basic blocks
/// where the value is live in.
bool findLiveInMBBs(const LiveRange &LR,
SmallVectorImpl<MachineBasicBlock*> &MBBs) const;
// Interval creation
LiveInterval &getOrCreateInterval(unsigned reg) {
Reg2IntervalMap::iterator I = r2iMap_.find(reg);
if (I == r2iMap_.end())
I = r2iMap_.insert(I, std::make_pair(reg, createInterval(reg)));
return I->second;
}
/// addLiveRangeToEndOfBlock - Given a register and an instruction,
/// adds a live range from that instruction to the end of its MBB.
LiveRange addLiveRangeToEndOfBlock(unsigned reg,
MachineInstr* startInst);
// Interval removal
void removeInterval(unsigned Reg) {
r2iMap_.erase(Reg);
}
/// isRemoved - returns true if the specified machine instr has been
/// removed.
bool isRemoved(MachineInstr* instr) const {
return !mi2iMap_.count(instr);
}
/// RemoveMachineInstrFromMaps - This marks the specified machine instr as
/// deleted.
void RemoveMachineInstrFromMaps(MachineInstr *MI) {
// remove index -> MachineInstr and
// MachineInstr -> index mappings
Mi2IndexMap::iterator mi2i = mi2iMap_.find(MI);
if (mi2i != mi2iMap_.end()) {
i2miMap_[mi2i->second/InstrSlots::NUM] = 0;
mi2iMap_.erase(mi2i);
}
}
/// ReplaceMachineInstrInMaps - Replacing a machine instr with a new one in
/// maps used by register allocator.
void ReplaceMachineInstrInMaps(MachineInstr *MI, MachineInstr *NewMI) {
Mi2IndexMap::iterator mi2i = mi2iMap_.find(MI);
if (mi2i == mi2iMap_.end())
return;
i2miMap_[mi2i->second/InstrSlots::NUM] = NewMI;
Mi2IndexMap::iterator it = mi2iMap_.find(MI);
assert(it != mi2iMap_.end() && "Invalid instruction!");
unsigned Index = it->second;
mi2iMap_.erase(it);
mi2iMap_[NewMI] = Index;
}
BumpPtrAllocator& getVNInfoAllocator() { return VNInfoAllocator; }
/// getVNInfoSourceReg - Helper function that parses the specified VNInfo
/// copy field and returns the source register that defines it.
unsigned getVNInfoSourceReg(const VNInfo *VNI) const;
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
virtual void releaseMemory();
/// runOnMachineFunction - pass entry point
virtual bool runOnMachineFunction(MachineFunction&);
/// print - Implement the dump method.
virtual void print(std::ostream &O, const Module* = 0) const;
void print(std::ostream *O, const Module* M = 0) const {
if (O) print(*O, M);
}
/// addIntervalsForSpills - Create new intervals for spilled defs / uses of
/// the given interval. FIXME: It also returns the weight of the spill slot
/// (if any is created) by reference. This is temporary.
std::vector<LiveInterval*>
addIntervalsForSpills(const LiveInterval& i,
const MachineLoopInfo *loopInfo, VirtRegMap& vrm,
float &SSWeight);
/// spillPhysRegAroundRegDefsUses - Spill the specified physical register
/// around all defs and uses of the specified interval.
void spillPhysRegAroundRegDefsUses(const LiveInterval &li,
unsigned PhysReg, VirtRegMap &vrm);
/// isReMaterializable - Returns true if every definition of MI of every
/// val# of the specified interval is re-materializable. Also returns true
/// by reference if all of the defs are load instructions.
bool isReMaterializable(const LiveInterval &li, bool &isLoad);
/// getRepresentativeReg - Find the largest super register of the specified
/// physical register.
unsigned getRepresentativeReg(unsigned Reg) const;
/// getNumConflictsWithPhysReg - Return the number of uses and defs of the
/// specified interval that conflicts with the specified physical register.
unsigned getNumConflictsWithPhysReg(const LiveInterval &li,
unsigned PhysReg) const;
/// computeNumbering - Compute the index numbering.
void computeNumbering();
private:
/// computeIntervals - Compute live intervals.
void computeIntervals();
/// handleRegisterDef - update intervals for a register def
/// (calls handlePhysicalRegisterDef and
/// handleVirtualRegisterDef)
void handleRegisterDef(MachineBasicBlock *MBB,
MachineBasicBlock::iterator MI, unsigned MIIdx,
MachineOperand& MO);
/// handleVirtualRegisterDef - update intervals for a virtual
/// register def
void handleVirtualRegisterDef(MachineBasicBlock *MBB,
MachineBasicBlock::iterator MI,
unsigned MIIdx, MachineOperand& MO,
LiveInterval& interval);
/// handlePhysicalRegisterDef - update intervals for a physical register
/// def.
void handlePhysicalRegisterDef(MachineBasicBlock* mbb,
MachineBasicBlock::iterator mi,
unsigned MIIdx, MachineOperand& MO,
LiveInterval &interval,
MachineInstr *CopyMI);
/// handleLiveInRegister - Create interval for a livein register.
void handleLiveInRegister(MachineBasicBlock* mbb,
unsigned MIIdx,
LiveInterval &interval, bool isAlias = false);
/// getReMatImplicitUse - If the remat definition MI has one (for now, we
/// only allow one) virtual register operand, then its uses are implicitly
/// using the register. Returns the virtual register.
unsigned getReMatImplicitUse(const LiveInterval &li,
MachineInstr *MI) const;
/// isValNoAvailableAt - Return true if the val# of the specified interval
/// which reaches the given instruction also reaches the specified use
/// index.
bool isValNoAvailableAt(const LiveInterval &li, MachineInstr *MI,
unsigned UseIdx) const;
/// isReMaterializable - Returns true if the definition MI of the specified
/// val# of the specified interval is re-materializable. Also returns true
/// by reference if the def is a load.
bool isReMaterializable(const LiveInterval &li, const VNInfo *ValNo,
MachineInstr *MI, bool &isLoad);
/// tryFoldMemoryOperand - Attempts to fold either a spill / restore from
/// slot / to reg or any rematerialized load into ith operand of specified
/// MI. If it is successul, MI is updated with the newly created MI and
/// returns true.
bool tryFoldMemoryOperand(MachineInstr* &MI, VirtRegMap &vrm,
MachineInstr *DefMI, unsigned InstrIdx,
SmallVector<unsigned, 2> &Ops,
bool isSS, int Slot, unsigned Reg);
/// canFoldMemoryOperand - Return true if the specified load / store
/// folding is possible.
bool canFoldMemoryOperand(MachineInstr *MI,
SmallVector<unsigned, 2> &Ops,
bool ReMatLoadSS) const;
/// anyKillInMBBAfterIdx - Returns true if there is a kill of the specified
/// VNInfo that's after the specified index but is within the basic block.
bool anyKillInMBBAfterIdx(const LiveInterval &li, const VNInfo *VNI,
MachineBasicBlock *MBB, unsigned Idx) const;
/// intervalIsInOneMBB - Returns true if the specified interval is entirely
/// within a single basic block.
bool intervalIsInOneMBB(const LiveInterval &li) const;
/// hasAllocatableSuperReg - Return true if the specified physical register
/// has any super register that's allocatable.
bool hasAllocatableSuperReg(unsigned Reg) const;
/// SRInfo - Spill / restore info.
struct SRInfo {
int index;
unsigned vreg;
bool canFold;
SRInfo(int i, unsigned vr, bool f) : index(i), vreg(vr), canFold(f) {};
};
bool alsoFoldARestore(int Id, int index, unsigned vr,
BitVector &RestoreMBBs,
std::map<unsigned,std::vector<SRInfo> >&RestoreIdxes);
void eraseRestoreInfo(int Id, int index, unsigned vr,
BitVector &RestoreMBBs,
std::map<unsigned,std::vector<SRInfo> >&RestoreIdxes);
/// handleSpilledImpDefs - Remove IMPLICIT_DEF instructions which are being
/// spilled and create empty intervals for their uses.
void handleSpilledImpDefs(const LiveInterval &li, VirtRegMap &vrm,
const TargetRegisterClass* rc,
std::vector<LiveInterval*> &NewLIs);
/// rewriteImplicitOps - Rewrite implicit use operands of MI (i.e. uses of
/// interval on to-be re-materialized operands of MI) with new register.
void rewriteImplicitOps(const LiveInterval &li,
MachineInstr *MI, unsigned NewVReg, VirtRegMap &vrm);
/// rewriteInstructionForSpills, rewriteInstructionsForSpills - Helper
/// functions for addIntervalsForSpills to rewrite uses / defs for the given
/// live range.
bool rewriteInstructionForSpills(const LiveInterval &li, const VNInfo *VNI,
bool TrySplit, unsigned index, unsigned end, MachineInstr *MI,
MachineInstr *OrigDefMI, MachineInstr *DefMI, unsigned Slot, int LdSlot,
bool isLoad, bool isLoadSS, bool DefIsReMat, bool CanDelete,
VirtRegMap &vrm, const TargetRegisterClass* rc,
SmallVector<int, 4> &ReMatIds, const MachineLoopInfo *loopInfo,
unsigned &NewVReg, unsigned ImpUse, bool &HasDef, bool &HasUse,
std::map<unsigned,unsigned> &MBBVRegsMap,
std::vector<LiveInterval*> &NewLIs, float &SSWeight);
void rewriteInstructionsForSpills(const LiveInterval &li, bool TrySplit,
LiveInterval::Ranges::const_iterator &I,
MachineInstr *OrigDefMI, MachineInstr *DefMI, unsigned Slot, int LdSlot,
bool isLoad, bool isLoadSS, bool DefIsReMat, bool CanDelete,
VirtRegMap &vrm, const TargetRegisterClass* rc,
SmallVector<int, 4> &ReMatIds, const MachineLoopInfo *loopInfo,
BitVector &SpillMBBs,
std::map<unsigned,std::vector<SRInfo> > &SpillIdxes,
BitVector &RestoreMBBs,
std::map<unsigned,std::vector<SRInfo> > &RestoreIdxes,
std::map<unsigned,unsigned> &MBBVRegsMap,
std::vector<LiveInterval*> &NewLIs, float &SSWeight);
static LiveInterval createInterval(unsigned Reg);
void printRegName(unsigned reg) const;
};
} // End llvm namespace
#endif