//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 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' abd 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).
#include "llvm/CodeGen/LiveInterval.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/Allocator.h"
+#include <cmath>
namespace llvm {
+ class AliasAnalysis;
class LiveVariables;
- class MRegisterInfo;
+ 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 MRegisterInfo* mri_;
+ const TargetRegisterInfo* tri_;
const TargetInstrInfo* tii_;
+ AliasAnalysis *aa_;
LiveVariables* lv_;
/// Special pool allocator for VNInfo's (LiveInterval val#).
/// specified basic block.
std::vector<std::pair<unsigned, unsigned> > MBB2IdxMap;
- typedef std::map<MachineInstr*, unsigned> Mi2IndexMap;
+ /// Idx2MBBMap - Sorted list of pairs of index of first instruction
+ /// and MBB id.
+ std::vector<IdxMBBPair> Idx2MBBMap;
+
+ /// FunctionSize - The number of instructions present in the function
+ uint64_t FunctionSize;
+
+ typedef DenseMap<const MachineInstr*, unsigned> Mi2IndexMap;
Mi2IndexMap mi2iMap_;
typedef std::vector<MachineInstr*> Index2MiMap;
Index2MiMap i2miMap_;
- typedef std::map<unsigned, LiveInterval> Reg2IntervalMap;
+ typedef DenseMap<unsigned, LiveInterval*> Reg2IntervalMap;
Reg2IntervalMap r2iMap_;
+ DenseMap<MachineBasicBlock*, unsigned> terminatorGaps;
+
BitVector allocatableRegs_;
std::vector<MachineInstr*> ClonedMIs;
+ typedef LiveInterval::InstrSlots InstrSlots;
+
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
- };
- };
+ LiveIntervals() : MachineFunctionPass(&ID) {}
static unsigned getBaseIndex(unsigned index) {
return index - (index % InstrSlots::NUM);
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 r2iMap_.size(); }
+ 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;
+ 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;
+ return *I->second;
}
bool hasInterval(unsigned reg) const {
return MBB2IdxMap[MBBNo].second;
}
+ /// getScaledIntervalSize - 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.
+ double getScaledIntervalSize(LiveInterval& I) {
+ return (1000.0 / InstrSlots::NUM * I.getSize()) / i2miMap_.size();
+ }
+
+ /// getApproximateInstructionCount - computes an estimate of the number
+ /// of instructions in a given LiveInterval.
+ unsigned getApproximateInstructionCount(LiveInterval& I) {
+ double IntervalPercentage = getScaledIntervalSize(I) / 1000.0;
+ return (unsigned)(IntervalPercentage * FunctionSize);
+ }
+
+ /// 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 {
+ unsigned getInstructionIndex(const MachineInstr* instr) const {
Mi2IndexMap::const_iterator it = mi2iMap_.find(instr);
assert(it != mi2iMap_.end() && "Invalid instruction!");
return it->second;
return i2miMap_[index];
}
+ /// hasGapBeforeInstr - Return true if the previous instruction slot,
+ /// i.e. Index - InstrSlots::NUM, is not occupied.
+ bool hasGapBeforeInstr(unsigned Index) {
+ Index = getBaseIndex(Index - InstrSlots::NUM);
+ return getInstructionFromIndex(Index) == 0;
+ }
+
+ /// hasGapAfterInstr - Return true if the successive instruction slot,
+ /// i.e. Index + InstrSlots::Num, is not occupied.
+ bool hasGapAfterInstr(unsigned Index) {
+ Index = getBaseIndex(Index + InstrSlots::NUM);
+ return getInstructionFromIndex(Index) == 0;
+ }
+
+ /// findGapBeforeInstr - Find an empty instruction slot before the
+ /// specified index. If "Furthest" is true, find one that's furthest
+ /// away from the index (but before any index that's occupied).
+ unsigned findGapBeforeInstr(unsigned Index, bool Furthest = false) {
+ Index = getBaseIndex(Index - InstrSlots::NUM);
+ if (getInstructionFromIndex(Index))
+ return 0; // No gap!
+ if (!Furthest)
+ return Index;
+ unsigned PrevIndex = getBaseIndex(Index - InstrSlots::NUM);
+ while (getInstructionFromIndex(Index)) {
+ Index = PrevIndex;
+ PrevIndex = getBaseIndex(Index - InstrSlots::NUM);
+ }
+ return Index;
+ }
+
+ /// InsertMachineInstrInMaps - Insert the specified machine instruction
+ /// into the instruction index map at the given index.
+ void InsertMachineInstrInMaps(MachineInstr *MI, unsigned Index) {
+ i2miMap_[Index / InstrSlots::NUM] = MI;
+ Mi2IndexMap::iterator it = mi2iMap_.find(MI);
+ assert(it == mi2iMap_.end() && "Already in map!");
+ mi2iMap_[MI] = 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);
+
+ /// conflictsWithPhysRegRef - Similar to conflictsWithPhysRegRef except
+ /// it can check use as well.
+ bool conflictsWithPhysRegRef(LiveInterval &li, unsigned Reg,
+ bool CheckUse,
+ SmallPtrSet<MachineInstr*,32> &JoinedCopies);
+
+ /// 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
+ /// in which the value is live.
+ bool findLiveInMBBs(unsigned Start, unsigned End,
+ SmallVectorImpl<MachineBasicBlock*> &MBBs) const;
+
+ /// findReachableMBBs - Return a list MBB that can be reached via any
+ /// branch or fallthroughs. Return true if the list is not empty.
+ bool findReachableMBBs(unsigned Start, unsigned End,
+ 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;
+ I = r2iMap_.insert(std::make_pair(reg, createInterval(reg))).first;
+ return *I->second;
}
- std::vector<LiveInterval*> addIntervalsForSpills(const LiveInterval& i,
- VirtRegMap& vrm, unsigned reg);
+ /// dupInterval - Duplicate a live interval. The caller is responsible for
+ /// managing the allocated memory.
+ LiveInterval *dupInterval(LiveInterval *li);
+
+ /// 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);
+ DenseMap<unsigned, LiveInterval*>::iterator I = r2iMap_.find(Reg);
+ delete I->second;
+ r2iMap_.erase(I);
}
- /// isRemoved - returns true if the specified machine instr has been
- /// removed.
- bool isRemoved(MachineInstr* instr) const {
+ /// isNotInMIMap - returns true if the specified machine instr has been
+ /// removed or was never entered in the map.
+ bool isNotInMIMap(MachineInstr* instr) const {
return !mi2iMap_.count(instr);
}
}
}
+ /// 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();
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,
+ SmallVectorImpl<LiveInterval*> &SpillIs,
+ const MachineLoopInfo *loopInfo, VirtRegMap& vrm);
+
+ /// addIntervalsForSpillsFast - Quickly create new intervals for spilled
+ /// defs / uses without remat or splitting.
+ std::vector<LiveInterval*>
+ addIntervalsForSpillsFast(const LiveInterval &li,
+ const MachineLoopInfo *loopInfo, VirtRegMap &vrm);
+
+ /// spillPhysRegAroundRegDefsUses - Spill the specified physical register
+ /// around all defs and uses of the specified interval. Return true if it
+ /// was able to cut its interval.
+ bool 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,
+ SmallVectorImpl<LiveInterval*> &SpillIs,
+ bool &isLoad);
+
+ /// isReMaterializable - Returns true if the definition MI of the specified
+ /// val# of the specified interval is re-materializable.
+ bool isReMaterializable(const LiveInterval &li, const VNInfo *ValNo,
+ MachineInstr *MI);
+
+ /// 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;
+
+ /// processImplicitDefs - Process IMPLICIT_DEF instructions. Add isUndef
+ /// marker to implicit_def defs and their uses.
+ void processImplicitDefs();
+
+ /// computeNumbering - Compute the index numbering.
+ void computeNumbering();
+
+ /// scaleNumbering - Rescale interval numbers to introduce gaps for new
+ /// instructions
+ void scaleNumbering(int factor);
+
+ /// intervalIsInOneMBB - Returns true if the specified interval is entirely
+ /// within a single basic block.
+ bool intervalIsInOneMBB(const LiveInterval &li) const;
+
private:
/// computeIntervals - Compute live intervals.
void computeIntervals();
/// handleVirtualRegisterDef)
void handleRegisterDef(MachineBasicBlock *MBB,
MachineBasicBlock::iterator MI, unsigned MIIdx,
- unsigned reg);
+ MachineOperand& MO, unsigned MOIdx);
/// handleVirtualRegisterDef - update intervals for a virtual
/// register def
void handleVirtualRegisterDef(MachineBasicBlock *MBB,
MachineBasicBlock::iterator MI,
- unsigned MIIdx,
- LiveInterval& interval);
+ unsigned MIIdx, MachineOperand& MO,
+ unsigned MOIdx, LiveInterval& interval);
/// handlePhysicalRegisterDef - update intervals for a physical register
/// def.
void handlePhysicalRegisterDef(MachineBasicBlock* mbb,
MachineBasicBlock::iterator mi,
- unsigned MIIdx,
+ unsigned MIIdx, MachineOperand& MO,
LiveInterval &interval,
- unsigned SrcReg);
+ 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.
+ /// 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);
+ MachineInstr *MI,
+ SmallVectorImpl<LiveInterval*> &SpillIs,
+ 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 index, unsigned i,
- bool isSS, int slot, unsigned reg);
+ 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;
+
+ /// 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) {};
+ };
- static LiveInterval createInterval(unsigned Reg);
+ bool alsoFoldARestore(int Id, int index, unsigned vr,
+ BitVector &RestoreMBBs,
+ DenseMap<unsigned,std::vector<SRInfo> >&RestoreIdxes);
+ void eraseRestoreInfo(int Id, int index, unsigned vr,
+ BitVector &RestoreMBBs,
+ DenseMap<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,
+ DenseMap<unsigned,unsigned> &MBBVRegsMap,
+ std::vector<LiveInterval*> &NewLIs);
+ 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,
+ DenseMap<unsigned,std::vector<SRInfo> > &SpillIdxes,
+ BitVector &RestoreMBBs,
+ DenseMap<unsigned,std::vector<SRInfo> > &RestoreIdxes,
+ DenseMap<unsigned,unsigned> &MBBVRegsMap,
+ std::vector<LiveInterval*> &NewLIs);
+
+ static LiveInterval* createInterval(unsigned Reg);
void printRegName(unsigned reg) const;
};
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