//
// 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 LiveRange and LiveInterval classes. Given some
// numbering of each the machine instructions an interval [i, j) is said to be a
-// live interval for register v if there is no instruction with number j' > j
+// 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). Each
#ifndef LLVM_CODEGEN_LIVEINTERVAL_H
#define LLVM_CODEGEN_LIVEINTERVAL_H
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/Allocator.h"
+#include "llvm/Support/AlignOf.h"
#include <iosfwd>
-#include <vector>
#include <cassert>
+#include <climits>
namespace llvm {
+ class MachineInstr;
+ class MachineRegisterInfo;
+ class TargetRegisterInfo;
+ struct LiveInterval;
+
+ /// VNInfo - Value Number Information.
+ /// This class holds information about a machine level values, including
+ /// definition and use points.
+ ///
+ /// Care must be taken in interpreting the def index of the value. The
+ /// following rules apply:
+ ///
+ /// If the isDefAccurate() method returns false then def does not contain the
+ /// index of the defining MachineInstr, or even (necessarily) to a
+ /// MachineInstr at all. In general such a def index is not meaningful
+ /// and should not be used. The exception is that, for values originally
+ /// defined by PHI instructions, after PHI elimination def will contain the
+ /// index of the MBB in which the PHI originally existed. This can be used
+ /// to insert code (spills or copies) which deals with the value, which will
+ /// be live in to the block.
+
+ class VNInfo {
+ private:
+ enum {
+ HAS_PHI_KILL = 1,
+ REDEF_BY_EC = 1 << 1,
+ IS_PHI_DEF = 1 << 2,
+ IS_UNUSED = 1 << 3,
+ IS_DEF_ACCURATE = 1 << 4
+ };
+
+ unsigned char flags;
+
+ public:
+ /// Holds information about individual kills.
+ struct KillInfo {
+ bool isPHIKill : 1;
+ unsigned killIdx : 31;
+
+ KillInfo(bool isPHIKill, unsigned killIdx)
+ : isPHIKill(isPHIKill), killIdx(killIdx) {
+
+ assert(killIdx != 0 && "Zero kill indices are no longer permitted.");
+ }
+
+ };
+
+ typedef SmallVector<KillInfo, 4> KillSet;
+
+ /// The ID number of this value.
+ unsigned id;
+
+ /// The index of the defining instruction (if isDefAccurate() returns true).
+ unsigned def;
+ MachineInstr *copy;
+ KillSet kills;
+
+ VNInfo()
+ : flags(IS_UNUSED), id(~1U), def(0), copy(0) {}
+
+ /// VNInfo constructor.
+ /// d is presumed to point to the actual defining instr. If it doesn't
+ /// setIsDefAccurate(false) should be called after construction.
+ VNInfo(unsigned i, unsigned d, MachineInstr *c)
+ : flags(IS_DEF_ACCURATE), id(i), def(d), copy(c) {}
+
+ /// VNInfo construtor, copies values from orig, except for the value number.
+ VNInfo(unsigned i, const VNInfo &orig)
+ : flags(orig.flags), id(i), def(orig.def), copy(orig.copy),
+ kills(orig.kills) {}
+
+ /// Used for copying value number info.
+ unsigned getFlags() const { return flags; }
+ void setFlags(unsigned flags) { this->flags = flags; }
+
+ /// Returns true if one or more kills are PHI nodes.
+ bool hasPHIKill() const { return flags & HAS_PHI_KILL; }
+ void setHasPHIKill(bool hasKill) {
+ if (hasKill)
+ flags |= HAS_PHI_KILL;
+ else
+ flags &= ~HAS_PHI_KILL;
+ }
+
+ /// Returns true if this value is re-defined by an early clobber somewhere
+ /// during the live range.
+ bool hasRedefByEC() const { return flags & REDEF_BY_EC; }
+ void setHasRedefByEC(bool hasRedef) {
+ if (hasRedef)
+ flags |= REDEF_BY_EC;
+ else
+ flags &= ~REDEF_BY_EC;
+ }
+
+ /// Returns true if this value is defined by a PHI instruction (or was,
+ /// PHI instrucions may have been eliminated).
+ bool isPHIDef() const { return flags & IS_PHI_DEF; }
+ void setIsPHIDef(bool phiDef) {
+ if (phiDef)
+ flags |= IS_PHI_DEF;
+ else
+ flags &= ~IS_PHI_DEF;
+ }
+
+ /// Returns true if this value is unused.
+ bool isUnused() const { return flags & IS_UNUSED; }
+ void setIsUnused(bool unused) {
+ if (unused)
+ flags |= IS_UNUSED;
+ else
+ flags &= ~IS_UNUSED;
+ }
+
+ /// Returns true if the def is accurate.
+ bool isDefAccurate() const { return flags & IS_DEF_ACCURATE; }
+ void setIsDefAccurate(bool defAccurate) {
+ if (defAccurate)
+ flags |= IS_DEF_ACCURATE;
+ else
+ flags &= ~IS_DEF_ACCURATE;
+ }
+
+ };
+
+ inline bool operator<(const VNInfo::KillInfo &k1, const VNInfo::KillInfo &k2) {
+ return k1.killIdx < k2.killIdx;
+ }
+
+ inline bool operator<(const VNInfo::KillInfo &k, unsigned idx) {
+ return k.killIdx < idx;
+ }
+
+ inline bool operator<(unsigned idx, const VNInfo::KillInfo &k) {
+ return idx < k.killIdx;
+ }
+
/// LiveRange structure - This represents a simple register range in the
/// program, with an inclusive start point and an exclusive end point.
/// These ranges are rendered as [start,end).
struct LiveRange {
unsigned start; // Start point of the interval (inclusive)
unsigned end; // End point of the interval (exclusive)
- unsigned ValId; // identifier for the value contained in this interval.
+ VNInfo *valno; // identifier for the value contained in this interval.
- LiveRange(unsigned S, unsigned E, unsigned V) : start(S), end(E), ValId(V) {
+ LiveRange(unsigned S, unsigned E, VNInfo *V) : start(S), end(E), valno(V) {
assert(S < E && "Cannot create empty or backwards range");
}
}
void dump() const;
+ void print(std::ostream &os) const;
+ void print(std::ostream *os) const { if (os) print(*os); }
private:
LiveRange(); // DO NOT IMPLEMENT
};
+
std::ostream& operator<<(std::ostream& os, const LiveRange &LR);
+
inline bool operator<(unsigned V, const LiveRange &LR) {
return V < LR.start;
}
+ inline bool operator<(const LiveRange &LR, unsigned V) {
+ return LR.start < V;
+ }
/// LiveInterval - This class represents some number of live ranges for a
/// register or value. This class also contains a bit of register allocator
/// state.
- struct LiveInterval {
- typedef std::vector<LiveRange> Ranges;
- unsigned reg; // the register of this interval
+ class LiveInterval {
+ public:
+
+ typedef SmallVector<LiveRange,4> Ranges;
+ typedef SmallVector<VNInfo*,4> VNInfoList;
+
+ unsigned reg; // the register or stack slot of this interval
+ // if the top bits is set, it represents a stack slot.
float weight; // weight of this interval
Ranges ranges; // the ranges in which this register is live
+ VNInfoList valnos; // value#'s
+
+ struct InstrSlots {
+ enum {
+ LOAD = 0,
+ USE = 1,
+ DEF = 2,
+ STORE = 3,
+ NUM = 4
+ };
+
+ static unsigned scale(unsigned slot, unsigned factor) {
+ unsigned index = slot / NUM,
+ offset = slot % NUM;
+ assert(index <= ~0U / (factor * NUM) &&
+ "Rescaled interval would overflow");
+ return index * NUM * factor + offset;
+ }
+
+ };
+
+ LiveInterval(unsigned Reg, float Weight, bool IsSS = false)
+ : reg(Reg), weight(Weight) {
+ if (IsSS)
+ reg = reg | (1U << (sizeof(unsigned)*CHAR_BIT-1));
+ }
+
+ typedef Ranges::iterator iterator;
+ iterator begin() { return ranges.begin(); }
+ iterator end() { return ranges.end(); }
+
+ typedef Ranges::const_iterator const_iterator;
+ const_iterator begin() const { return ranges.begin(); }
+ const_iterator end() const { return ranges.end(); }
+
+ typedef VNInfoList::iterator vni_iterator;
+ vni_iterator vni_begin() { return valnos.begin(); }
+ vni_iterator vni_end() { return valnos.end(); }
+
+ typedef VNInfoList::const_iterator const_vni_iterator;
+ const_vni_iterator vni_begin() const { return valnos.begin(); }
+ const_vni_iterator vni_end() const { return valnos.end(); }
+
+ /// advanceTo - Advance the specified iterator to point to the LiveRange
+ /// containing the specified position, or end() if the position is past the
+ /// end of the interval. If no LiveRange contains this position, but the
+ /// position is in a hole, this method returns an iterator pointing the the
+ /// LiveRange immediately after the hole.
+ iterator advanceTo(iterator I, unsigned Pos) {
+ if (Pos >= endNumber())
+ return end();
+ while (I->end <= Pos) ++I;
+ return I;
+ }
+
+ void clear() {
+ while (!valnos.empty()) {
+ VNInfo *VNI = valnos.back();
+ valnos.pop_back();
+ VNI->~VNInfo();
+ }
+
+ ranges.clear();
+ }
- LiveInterval(unsigned Reg, float Weight)
- : reg(Reg), weight(Weight), NumValues(0) {
+ /// isStackSlot - Return true if this is a stack slot interval.
+ ///
+ bool isStackSlot() const {
+ return reg & (1U << (sizeof(unsigned)*CHAR_BIT-1));
}
- void swap(LiveInterval& other) {
- std::swap(reg, other.reg);
- std::swap(weight, other.weight);
- ranges.swap(other.ranges);
- std::swap(NumValues, other.NumValues);
+ /// getStackSlotIndex - Return stack slot index if this is a stack slot
+ /// interval.
+ int getStackSlotIndex() const {
+ assert(isStackSlot() && "Interval is not a stack slot interval!");
+ return reg & ~(1U << (sizeof(unsigned)*CHAR_BIT-1));
}
- bool containsOneValue() const { return NumValues == 1; }
+ bool hasAtLeastOneValue() const { return !valnos.empty(); }
+
+ bool containsOneValue() const { return valnos.size() == 1; }
- unsigned getNextValue() {
- return NumValues++;
+ unsigned getNumValNums() const { return (unsigned)valnos.size(); }
+
+ /// getValNumInfo - Returns pointer to the specified val#.
+ ///
+ inline VNInfo *getValNumInfo(unsigned ValNo) {
+ return valnos[ValNo];
+ }
+ inline const VNInfo *getValNumInfo(unsigned ValNo) const {
+ return valnos[ValNo];
+ }
+
+ /// copyValNumInfo - Copy the value number info for one value number to
+ /// another.
+ void copyValNumInfo(VNInfo *DstValNo, const VNInfo *SrcValNo) {
+ DstValNo->def = SrcValNo->def;
+ DstValNo->copy = SrcValNo->copy;
+ DstValNo->setFlags(SrcValNo->getFlags());
+ DstValNo->kills = SrcValNo->kills;
}
+ /// getNextValue - Create a new value number and return it. MIIdx specifies
+ /// the instruction that defines the value number.
+ VNInfo *getNextValue(unsigned MIIdx, MachineInstr *CopyMI,
+ bool isDefAccurate, BumpPtrAllocator &VNInfoAllocator) {
+
+ assert(MIIdx != ~0u && MIIdx != ~1u &&
+ "PHI def / unused flags should now be passed explicitly.");
+ VNInfo *VNI =
+ static_cast<VNInfo*>(VNInfoAllocator.Allocate((unsigned)sizeof(VNInfo),
+ alignof<VNInfo>()));
+ new (VNI) VNInfo((unsigned)valnos.size(), MIIdx, CopyMI);
+ VNI->setIsDefAccurate(isDefAccurate);
+ valnos.push_back(VNI);
+ return VNI;
+ }
+
+ /// Create a copy of the given value. The new value will be identical except
+ /// for the Value number.
+ VNInfo *createValueCopy(const VNInfo *orig, BumpPtrAllocator &VNInfoAllocator) {
+
+ VNInfo *VNI =
+ static_cast<VNInfo*>(VNInfoAllocator.Allocate((unsigned)sizeof(VNInfo),
+ alignof<VNInfo>()));
+
+ new (VNI) VNInfo((unsigned)valnos.size(), *orig);
+ valnos.push_back(VNI);
+ return VNI;
+ }
+
+ /// addKill - Add a kill instruction index to the specified value
+ /// number.
+ static void addKill(VNInfo *VNI, unsigned KillIdx, bool phiKill) {
+ VNInfo::KillSet &kills = VNI->kills;
+ VNInfo::KillInfo newKill(phiKill, KillIdx);
+ if (kills.empty()) {
+ kills.push_back(newKill);
+ } else {
+ VNInfo::KillSet::iterator
+ I = std::lower_bound(kills.begin(), kills.end(), newKill);
+ kills.insert(I, newKill);
+ }
+ }
+
+ /// addKills - Add a number of kills into the VNInfo kill vector. If this
+ /// interval is live at a kill point, then the kill is not added.
+ void addKills(VNInfo *VNI, const VNInfo::KillSet &kills) {
+ for (unsigned i = 0, e = static_cast<unsigned>(kills.size());
+ i != e; ++i) {
+ const VNInfo::KillInfo &Kill = kills[i];
+ if (!liveBeforeAndAt(Kill.killIdx)) {
+ VNInfo::KillSet::iterator
+ I = std::lower_bound(VNI->kills.begin(), VNI->kills.end(), Kill);
+ VNI->kills.insert(I, Kill);
+ }
+ }
+ }
+
+ /// removeKill - Remove the specified kill from the list of kills of
+ /// the specified val#.
+ static bool removeKill(VNInfo *VNI, unsigned KillIdx) {
+ VNInfo::KillSet &kills = VNI->kills;
+ VNInfo::KillSet::iterator
+ I = std::lower_bound(kills.begin(), kills.end(), KillIdx);
+ if (I != kills.end() && I->killIdx == KillIdx) {
+ kills.erase(I);
+ return true;
+ }
+ return false;
+ }
+
+ /// removeKills - Remove all the kills in specified range
+ /// [Start, End] of the specified val#.
+ static void removeKills(VNInfo *VNI, unsigned Start, unsigned End) {
+ VNInfo::KillSet &kills = VNI->kills;
+
+ VNInfo::KillSet::iterator
+ I = std::lower_bound(kills.begin(), kills.end(), Start);
+ VNInfo::KillSet::iterator
+ E = std::upper_bound(kills.begin(), kills.end(), End);
+ kills.erase(I, E);
+ }
+
+ /// isKill - Return true if the specified index is a kill of the
+ /// specified val#.
+ static bool isKill(const VNInfo *VNI, unsigned KillIdx) {
+ const VNInfo::KillSet &kills = VNI->kills;
+ VNInfo::KillSet::const_iterator
+ I = std::lower_bound(kills.begin(), kills.end(), KillIdx);
+ return I != kills.end() && I->killIdx == KillIdx;
+ }
+
+ /// isOnlyLROfValNo - Return true if the specified live range is the only
+ /// one defined by the its val#.
+ bool isOnlyLROfValNo(const LiveRange *LR) {
+ for (const_iterator I = begin(), E = end(); I != E; ++I) {
+ const LiveRange *Tmp = I;
+ if (Tmp != LR && Tmp->valno == LR->valno)
+ return false;
+ }
+ return true;
+ }
+
+ /// MergeValueNumberInto - This method is called when two value nubmers
+ /// are found to be equivalent. This eliminates V1, replacing all
+ /// LiveRanges with the V1 value number with the V2 value number. This can
+ /// cause merging of V1/V2 values numbers and compaction of the value space.
+ VNInfo* MergeValueNumberInto(VNInfo *V1, VNInfo *V2);
+
+ /// MergeInClobberRanges - For any live ranges that are not defined in the
+ /// current interval, but are defined in the Clobbers interval, mark them
+ /// used with an unknown definition value. Caller must pass in reference to
+ /// VNInfoAllocator since it will create a new val#.
+ void MergeInClobberRanges(const LiveInterval &Clobbers,
+ BumpPtrAllocator &VNInfoAllocator);
+
+ /// MergeInClobberRange - Same as MergeInClobberRanges except it merge in a
+ /// single LiveRange only.
+ void MergeInClobberRange(unsigned Start, unsigned End,
+ BumpPtrAllocator &VNInfoAllocator);
+
+ /// MergeValueInAsValue - Merge all of the live ranges of a specific val#
+ /// in RHS into this live interval as the specified value number.
+ /// The LiveRanges in RHS are allowed to overlap with LiveRanges in the
+ /// current interval, it will replace the value numbers of the overlaped
+ /// live ranges with the specified value number.
+ void MergeRangesInAsValue(const LiveInterval &RHS, VNInfo *LHSValNo);
+
+ /// MergeValueInAsValue - Merge all of the live ranges of a specific val#
+ /// in RHS into this live interval as the specified value number.
+ /// The LiveRanges in RHS are allowed to overlap with LiveRanges in the
+ /// current interval, but only if the overlapping LiveRanges have the
+ /// specified value number.
+ void MergeValueInAsValue(const LiveInterval &RHS,
+ const VNInfo *RHSValNo, VNInfo *LHSValNo);
+
+ /// Copy - Copy the specified live interval. This copies all the fields
+ /// except for the register of the interval.
+ void Copy(const LiveInterval &RHS, MachineRegisterInfo *MRI,
+ BumpPtrAllocator &VNInfoAllocator);
+
bool empty() const { return ranges.empty(); }
- /// start - Return the lowest numbered slot covered by interval.
- unsigned start() const {
- assert(!empty() && "empty interval for register");
+ /// beginNumber - Return the lowest numbered slot covered by interval.
+ unsigned beginNumber() const {
+ if (empty())
+ return 0;
return ranges.front().start;
}
- /// end - return the maximum point of the interval of the whole,
+ /// endNumber - return the maximum point of the interval of the whole,
/// exclusive.
- unsigned end() const {
- assert(!empty() && "empty interval for register");
+ unsigned endNumber() const {
+ if (empty())
+ return 0;
return ranges.back().end;
}
bool expiredAt(unsigned index) const {
- return end() <= (index + 1);
+ return index >= endNumber();
}
bool liveAt(unsigned index) const;
+ // liveBeforeAndAt - Check if the interval is live at the index and the
+ // index just before it. If index is liveAt, check if it starts a new live
+ // range.If it does, then check if the previous live range ends at index-1.
+ bool liveBeforeAndAt(unsigned index) const;
+
/// getLiveRangeContaining - Return the live range that contains the
/// specified index, or null if there is none.
- LiveRange *getLiveRangeContaining(unsigned Idx);
+ const LiveRange *getLiveRangeContaining(unsigned Idx) const {
+ const_iterator I = FindLiveRangeContaining(Idx);
+ return I == end() ? 0 : &*I;
+ }
+ /// getLiveRangeContaining - Return the live range that contains the
+ /// specified index, or null if there is none.
+ LiveRange *getLiveRangeContaining(unsigned Idx) {
+ iterator I = FindLiveRangeContaining(Idx);
+ return I == end() ? 0 : &*I;
+ }
- /// joinable - Two intervals are joinable if the either don't overlap at all
- /// or if the destination of the copy is a single assignment value, and it
- /// only overlaps with one value in the source interval.
- bool joinable(const LiveInterval& other, unsigned CopyIdx) const;
+ /// FindLiveRangeContaining - Return an iterator to the live range that
+ /// contains the specified index, or end() if there is none.
+ const_iterator FindLiveRangeContaining(unsigned Idx) const;
+
+ /// FindLiveRangeContaining - Return an iterator to the live range that
+ /// contains the specified index, or end() if there is none.
+ iterator FindLiveRangeContaining(unsigned Idx);
+
+ /// findDefinedVNInfo - Find the VNInfo that's defined at the specified
+ /// index (register interval) or defined by the specified register (stack
+ /// inteval).
+ VNInfo *findDefinedVNInfo(unsigned DefIdxOrReg) const;
+
+ /// overlaps - Return true if the intersection of the two live intervals is
+ /// not empty.
+ bool overlaps(const LiveInterval& other) const {
+ return overlapsFrom(other, other.begin());
+ }
+ /// overlaps - Return true if the live interval overlaps a range specified
+ /// by [Start, End).
+ bool overlaps(unsigned Start, unsigned End) const;
- bool overlaps(const LiveInterval& other) const;
+ /// overlapsFrom - Return true if the intersection of the two live intervals
+ /// is not empty. The specified iterator is a hint that we can begin
+ /// scanning the Other interval starting at I.
+ bool overlapsFrom(const LiveInterval& other, const_iterator I) const;
/// addRange - Add the specified LiveRange to this interval, merging
/// intervals as appropriate. This returns an iterator to the inserted live
addRangeFrom(LR, ranges.begin());
}
- /// join - Join two live intervals (this, and other) together. This
- /// operation is the result of a copy instruction in the source program,
- /// that occurs at index 'CopyIdx' that copies from 'other' to 'this'. This
- /// destroys 'other'.
- void join(LiveInterval& other, unsigned CopyIdx);
+ /// join - Join two live intervals (this, and other) together. This applies
+ /// mappings to the value numbers in the LHS/RHS intervals as specified. If
+ /// the intervals are not joinable, this aborts.
+ void join(LiveInterval &Other, const int *ValNoAssignments,
+ const int *RHSValNoAssignments,
+ SmallVector<VNInfo*, 16> &NewVNInfo,
+ MachineRegisterInfo *MRI);
+ /// isInOneLiveRange - Return true if the range specified is entirely in the
+ /// a single LiveRange of the live interval.
+ bool isInOneLiveRange(unsigned Start, unsigned End);
/// removeRange - Remove the specified range from this interval. Note that
- /// the range must already be in this interval in its entirety.
- void removeRange(unsigned Start, unsigned End);
+ /// the range must be a single LiveRange in its entirety.
+ void removeRange(unsigned Start, unsigned End, bool RemoveDeadValNo = false);
+
+ void removeRange(LiveRange LR, bool RemoveDeadValNo = false) {
+ removeRange(LR.start, LR.end, RemoveDeadValNo);
+ }
+
+ /// removeValNo - Remove all the ranges defined by the specified value#.
+ /// Also remove the value# from value# list.
+ void removeValNo(VNInfo *ValNo);
+
+ /// scaleNumbering - Renumber VNI and ranges to provide gaps for new
+ /// instructions.
+ void scaleNumbering(unsigned factor);
+
+ /// getSize - Returns the sum of sizes of all the LiveRange's.
+ ///
+ unsigned getSize() const;
bool operator<(const LiveInterval& other) const {
- return start() < other.start();
+ return beginNumber() < other.beginNumber();
}
+ void print(std::ostream &OS, const TargetRegisterInfo *TRI = 0) const;
+ void print(std::ostream *OS, const TargetRegisterInfo *TRI = 0) const {
+ if (OS) print(*OS, TRI);
+ }
void dump() const;
private:
- unsigned NumValues; // the number of distinct values in this interval.
+
Ranges::iterator addRangeFrom(LiveRange LR, Ranges::iterator From);
void extendIntervalEndTo(Ranges::iterator I, unsigned NewEnd);
Ranges::iterator extendIntervalStartTo(Ranges::iterator I, unsigned NewStr);
LiveInterval& operator=(const LiveInterval& rhs); // DO NOT IMPLEMENT
+
};
- std::ostream& operator<<(std::ostream& os, const LiveInterval& li);
+ inline std::ostream &operator<<(std::ostream &OS, const LiveInterval &LI) {
+ LI.print(OS);
+ return OS;
+ }
}
#endif