//
// 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
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/Allocator.h"
-#include "llvm/Support/Streams.h"
+#include "llvm/Support/AlignOf.h"
#include <iosfwd>
-#include <vector>
#include <cassert>
+#include <climits>
namespace llvm {
class MachineInstr;
- class MRegisterInfo;
+ class MachineRegisterInfo;
+ class TargetRegisterInfo;
struct LiveInterval;
- /// VNInfo - If the value number definition is undefined (e.g. phi
- /// merge point), it contains ~0u,x. If the value number is not in use, it
- /// contains ~1u,x to indicate that the value # is not used.
- /// def - Instruction # of the definition.
- /// reg - Source reg iff val# is defined by a copy; zero otherwise.
- /// kills - Instruction # of the kills. If a kill is an odd #, it means
- /// the kill is a phi join point.
- struct VNInfo {
+ /// 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;
- unsigned reg;
- SmallVector<unsigned, 4> kills;
- VNInfo() : id(~1U), def(~1U), reg(0) {}
- VNInfo(unsigned i, unsigned d, unsigned r)
- : id(i), def(d), reg(r) {}
+ 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).
/// 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 {
+ class LiveInterval {
+ public:
+
typedef SmallVector<LiveRange,4> Ranges;
typedef SmallVector<VNInfo*,4> VNInfoList;
- unsigned reg; // the register of this interval
- unsigned preference; // preferred register to allocate for this interval
+ 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;
+ }
- public:
- LiveInterval(unsigned Reg, float Weight)
- : reg(Reg), preference(0), weight(Weight) {
+ };
+
+ 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;
while (I->end <= Pos) ++I;
return I;
}
+
+ void clear() {
+ while (!valnos.empty()) {
+ VNInfo *VNI = valnos.back();
+ valnos.pop_back();
+ VNI->~VNInfo();
+ }
+
+ ranges.clear();
+ }
+
+ /// isStackSlot - Return true if this is a stack slot interval.
+ ///
+ bool isStackSlot() const {
+ return reg & (1U << (sizeof(unsigned)*CHAR_BIT-1));
+ }
+
+ /// 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 hasAtLeastOneValue() const { return !valnos.empty(); }
bool containsOneValue() const { return valnos.size() == 1; }
- unsigned getNumValNums() const { return valnos.size(); }
+ unsigned getNumValNums() const { return (unsigned)valnos.size(); }
/// getValNumInfo - Returns pointer to the specified val#.
///
/// copyValNumInfo - Copy the value number info for one value number to
/// another.
- void copyValNumInfo(VNInfo *DstValNo, VNInfo *SrcValNo) {
+ void copyValNumInfo(VNInfo *DstValNo, const VNInfo *SrcValNo) {
DstValNo->def = SrcValNo->def;
- DstValNo->reg = SrcValNo->reg;
+ 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, unsigned SrcReg) {
-#ifdef __GNUC__
- unsigned Alignment = __alignof__(VNInfo);
-#else
- // FIXME: ugly.
- unsigned Alignment = 8;
-#endif
- VNInfo *VNI= static_cast<VNInfo*>(VNInfoAllocator.Allocate(sizeof(VNInfo),
- Alignment));
- new (VNI) VNInfo(valnos.size(), MIIdx, SrcReg);
+ 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;
}
- /// addKillForValNum - Add a kill instruction index to the specified value
+ /// addKill - Add a kill instruction index to the specified value
/// number.
- static void addKill(VNInfo *VNI, unsigned KillIdx) {
- SmallVector<unsigned, 4> &kills = VNI->kills;
+ 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(KillIdx);
+ kills.push_back(newKill);
} else {
- SmallVector<unsigned, 4>::iterator
- I = std::lower_bound(kills.begin(), kills.end(), KillIdx);
- kills.insert(I, KillIdx);
+ 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 SmallVector<unsigned, 4> &kills) {
- for (unsigned i = 0, e = kills.size(); i != e; ++i) {
- unsigned KillIdx = kills[i];
- if (!liveAt(KillIdx)) {
- SmallVector<unsigned, 4>::iterator
- I = std::lower_bound(VNI->kills.begin(), VNI->kills.end(), KillIdx);
- VNI->kills.insert(I, KillIdx);
+ 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) {
- SmallVector<unsigned, 4> &kills = VNI->kills;
- SmallVector<unsigned, 4>::iterator
+ VNInfo::KillSet &kills = VNI->kills;
+ VNInfo::KillSet::iterator
I = std::lower_bound(kills.begin(), kills.end(), KillIdx);
- if (I != kills.end() && *I == KillIdx) {
+ if (I != kills.end() && I->killIdx == KillIdx) {
kills.erase(I);
return true;
}
/// removeKills - Remove all the kills in specified range
/// [Start, End] of the specified val#.
- void removeKills(VNInfo *VNI, unsigned Start, unsigned End) {
- SmallVector<unsigned, 4> &kills = VNI->kills;
- SmallVector<unsigned, 4>::iterator
+ 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);
- SmallVector<unsigned, 4>::iterator
+ 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.
- void MergeValueNumberInto(VNInfo *V1, VNInfo *V2);
+ 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
void MergeInClobberRanges(const LiveInterval &Clobbers,
BumpPtrAllocator &VNInfoAllocator);
- /// MergeRangesInAsValue - Merge all of the intervals 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.
+ /// 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(); }
/// beginNumber - Return the lowest numbered slot covered by interval.
unsigned beginNumber() const {
- assert(!empty() && "empty interval for register");
+ if (empty())
+ return 0;
return ranges.front().start;
}
/// endNumber - return the maximum point of the interval of the whole,
/// exclusive.
unsigned endNumber() const {
- assert(!empty() && "empty interval for register");
+ if (empty())
+ return 0;
return ranges.back().end;
}
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.
const LiveRange *getLiveRangeContaining(unsigned Idx) const {
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;
+ }
+
/// 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);
-
- /// getOverlapingRanges - Given another live interval which is defined as a
- /// copy from this one, return a list of all of the live ranges where the
- /// two overlap and have different value numbers.
- void getOverlapingRanges(const LiveInterval &Other, unsigned CopyIdx,
- std::vector<LiveRange*> &Ranges);
+ /// 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;
+
/// 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.
/// 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, int *ValNoAssignments,
- int *RHSValNoAssignments, SmallVector<VNInfo*, 16> &NewVNInfo);
+ 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) {
- removeRange(LR.start, LR.end);
+ 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;
return beginNumber() < other.beginNumber();
}
- void print(std::ostream &OS, const MRegisterInfo *MRI = 0) const;
- void print(std::ostream *OS, const MRegisterInfo *MRI = 0) const {
- if (OS) print(*OS, MRI);
+ 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:
+
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
+
};
inline std::ostream &operator<<(std::ostream &OS, const LiveInterval &LI) {
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