//
// 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 range 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
-// individual range is represented as an instance of LiveRange, and the whole
-// interval is represented as an instance of LiveInterval.
+// that v is live at i'. In this implementation ranges can have holes,
+// i.e. a range might look like [1,20), [50,65), [1000,1001). Each
+// individual segment is represented as an instance of LiveRange::Segment,
+// and the whole range is represented as an instance of LiveRange.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_LIVEINTERVAL_H
#define LLVM_CODEGEN_LIVEINTERVAL_H
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/Support/Streams.h"
-#include <iosfwd>
-#include <vector>
+#include "llvm/ADT/IntEqClasses.h"
+#include "llvm/CodeGen/SlotIndexes.h"
+#include "llvm/Support/AlignOf.h"
+#include "llvm/Support/Allocator.h"
#include <cassert>
+#include <climits>
+#include <set>
namespace llvm {
+ class CoalescerPair;
+ class LiveIntervals;
class MachineInstr;
- class MRegisterInfo;
+ class MachineRegisterInfo;
+ class TargetRegisterInfo;
+ class raw_ostream;
+ template <typename T, unsigned Small> class SmallPtrSet;
+
+ /// VNInfo - Value Number Information.
+ /// This class holds information about a machine level values, including
+ /// definition and use points.
+ ///
+ class VNInfo {
+ public:
+ typedef BumpPtrAllocator Allocator;
- /// 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.
+ /// The ID number of this value.
+ unsigned id;
- LiveRange(unsigned S, unsigned E, unsigned V) : start(S), end(E), ValId(V) {
- assert(S < E && "Cannot create empty or backwards range");
- }
+ /// The index of the defining instruction.
+ SlotIndex def;
- /// contains - Return true if the index is covered by this range.
- ///
- bool contains(unsigned I) const {
- return start <= I && I < end;
- }
+ /// VNInfo constructor.
+ VNInfo(unsigned i, SlotIndex d)
+ : id(i), def(d)
+ { }
- bool operator<(const LiveRange &LR) const {
- return start < LR.start || (start == LR.start && end < LR.end);
- }
- bool operator==(const LiveRange &LR) const {
- return start == LR.start && end == LR.end;
+ /// VNInfo construtor, copies values from orig, except for the value number.
+ VNInfo(unsigned i, const VNInfo &orig)
+ : id(i), def(orig.def)
+ { }
+
+ /// Copy from the parameter into this VNInfo.
+ void copyFrom(VNInfo &src) {
+ def = src.def;
}
- void dump() const;
- void print(std::ostream &os) const;
- void print(std::ostream *os) const { if (os) print(*os); }
+ /// Returns true if this value is defined by a PHI instruction (or was,
+ /// PHI instructions may have been eliminated).
+ /// PHI-defs begin at a block boundary, all other defs begin at register or
+ /// EC slots.
+ bool isPHIDef() const { return def.isBlock(); }
- private:
- LiveRange(); // DO NOT IMPLEMENT
+ /// Returns true if this value is unused.
+ bool isUnused() const { return !def.isValid(); }
+
+ /// Mark this value as unused.
+ void markUnused() { def = SlotIndex(); }
};
- std::ostream& operator<<(std::ostream& os, const LiveRange &LR);
+ /// Result of a LiveRange query. This class hides the implementation details
+ /// of live ranges, and it should be used as the primary interface for
+ /// examining live ranges around instructions.
+ class LiveQueryResult {
+ VNInfo *const EarlyVal;
+ VNInfo *const LateVal;
+ const SlotIndex EndPoint;
+ const bool Kill;
+ public:
+ LiveQueryResult(VNInfo *EarlyVal, VNInfo *LateVal, SlotIndex EndPoint,
+ bool Kill)
+ : EarlyVal(EarlyVal), LateVal(LateVal), EndPoint(EndPoint), Kill(Kill)
+ {}
+
+ /// Return the value that is live-in to the instruction. This is the value
+ /// that will be read by the instruction's use operands. Return NULL if no
+ /// value is live-in.
+ VNInfo *valueIn() const {
+ return EarlyVal;
+ }
- inline bool operator<(unsigned V, const LiveRange &LR) {
- return V < LR.start;
- }
+ /// Return true if the live-in value is killed by this instruction. This
+ /// means that either the live range ends at the instruction, or it changes
+ /// value.
+ bool isKill() const {
+ return Kill;
+ }
- inline bool operator<(const LiveRange &LR, unsigned V) {
- return LR.start < V;
- }
+ /// Return true if this instruction has a dead def.
+ bool isDeadDef() const {
+ return EndPoint.isDead();
+ }
- /// 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 SmallVector<LiveRange,4> Ranges;
- unsigned reg; // the register of this interval
- unsigned preference; // preferred register to allocate for this interval
- float weight; // weight of this interval
- MachineInstr* remat; // definition if the definition rematerializable
- Ranges ranges; // the ranges in which this register is live
-
- /// ValueNumberInfo - If the value number definition is undefined (e.g. phi
- /// merge point), it contains ~0,x,x. If the value number is not in use, it
- /// contains ~1,x,x to indicate that the value # is not used. The first
- /// entry is the instruction # of the definition, the second is the kill #.
- /// If the third value is non-zero, then the val# is defined by a copy and
- /// it represents the register number it is copied from.
- struct VNInfo {
- unsigned def;
- unsigned kill;
- unsigned reg;
- VNInfo() : def(~1U), kill(~0U), reg(0) {};
- VNInfo(unsigned d, unsigned k, unsigned r) : def(d), kill(k), reg(r) {};
- };
- private:
- SmallVector<VNInfo, 4> ValueNumberInfo;
- public:
+ /// Return the value leaving the instruction, if any. This can be a
+ /// live-through value, or a live def. A dead def returns NULL.
+ VNInfo *valueOut() const {
+ return isDeadDef() ? nullptr : LateVal;
+ }
- LiveInterval(unsigned Reg, float Weight)
- : reg(Reg), preference(0), weight(Weight), remat(NULL) {
+ /// Returns the value alive at the end of the instruction, if any. This can
+ /// be a live-through value, a live def or a dead def.
+ VNInfo *valueOutOrDead() const {
+ return LateVal;
}
- typedef Ranges::iterator iterator;
- iterator begin() { return ranges.begin(); }
- iterator end() { return ranges.end(); }
+ /// Return the value defined by this instruction, if any. This includes
+ /// dead defs, it is the value created by the instruction's def operands.
+ VNInfo *valueDefined() const {
+ return EarlyVal == LateVal ? nullptr : LateVal;
+ }
- typedef Ranges::const_iterator const_iterator;
- const_iterator begin() const { return ranges.begin(); }
- const_iterator end() const { return ranges.end(); }
+ /// Return the end point of the last live range segment to interact with
+ /// the instruction, if any.
+ ///
+ /// The end point is an invalid SlotIndex only if the live range doesn't
+ /// intersect the instruction at all.
+ ///
+ /// The end point may be at or past the end of the instruction's basic
+ /// block. That means the value was live out of the block.
+ SlotIndex endPoint() const {
+ return EndPoint;
+ }
+ };
+ /// This class represents the liveness of a register, stack slot, etc.
+ /// It manages an ordered list of Segment objects.
+ /// The Segments are organized in a static single assignment form: At places
+ /// where a new value is defined or different values reach a CFG join a new
+ /// segment with a new value number is used.
+ class LiveRange {
+ public:
- /// advanceTo - Advance the specified iterator to point to the LiveRange
+ /// This represents a simple continuous liveness interval for a value.
+ /// The start point is inclusive, the end point exclusive. These intervals
+ /// are rendered as [start,end).
+ struct Segment {
+ SlotIndex start; // Start point of the interval (inclusive)
+ SlotIndex end; // End point of the interval (exclusive)
+ VNInfo *valno; // identifier for the value contained in this segment.
+
+ Segment() : valno(nullptr) {}
+
+ Segment(SlotIndex S, SlotIndex E, VNInfo *V)
+ : start(S), end(E), valno(V) {
+ assert(S < E && "Cannot create empty or backwards segment");
+ }
+
+ /// Return true if the index is covered by this segment.
+ bool contains(SlotIndex I) const {
+ return start <= I && I < end;
+ }
+
+ /// Return true if the given interval, [S, E), is covered by this segment.
+ bool containsInterval(SlotIndex S, SlotIndex E) const {
+ assert((S < E) && "Backwards interval?");
+ return (start <= S && S < end) && (start < E && E <= end);
+ }
+
+ bool operator<(const Segment &Other) const {
+ return std::tie(start, end) < std::tie(Other.start, Other.end);
+ }
+ bool operator==(const Segment &Other) const {
+ return start == Other.start && end == Other.end;
+ }
+
+ void dump() const;
+ };
+
+ typedef SmallVector<Segment,4> Segments;
+ typedef SmallVector<VNInfo*,4> VNInfoList;
+
+ Segments segments; // the liveness segments
+ VNInfoList valnos; // value#'s
+
+ // The segment set is used temporarily to accelerate initial computation
+ // of live ranges of physical registers in computeRegUnitRange.
+ // After that the set is flushed to the segment vector and deleted.
+ typedef std::set<Segment> SegmentSet;
+ std::unique_ptr<SegmentSet> segmentSet;
+
+ typedef Segments::iterator iterator;
+ iterator begin() { return segments.begin(); }
+ iterator end() { return segments.end(); }
+
+ typedef Segments::const_iterator const_iterator;
+ const_iterator begin() const { return segments.begin(); }
+ const_iterator end() const { return segments.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(); }
+
+ /// Constructs a new LiveRange object.
+ LiveRange(bool UseSegmentSet = false)
+ : segmentSet(UseSegmentSet ? llvm::make_unique<SegmentSet>()
+ : nullptr) {}
+
+ /// Constructs a new LiveRange object by copying segments and valnos from
+ /// another LiveRange.
+ LiveRange(const LiveRange &Other, BumpPtrAllocator &Allocator) {
+ assert(Other.segmentSet == nullptr &&
+ "Copying of LiveRanges with active SegmentSets is not supported");
+
+ // Duplicate valnos.
+ for (const VNInfo *VNI : Other.valnos) {
+ createValueCopy(VNI, Allocator);
+ }
+ // Now we can copy segments and remap their valnos.
+ for (const Segment &S : Other.segments) {
+ segments.push_back(Segment(S.start, S.end, valnos[S.valno->id]));
+ }
+ }
+
+ /// advanceTo - Advance the specified iterator to point to the Segment
/// 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())
+ /// end of the range. If no Segment contains this position, but the
+ /// position is in a hole, this method returns an iterator pointing to the
+ /// Segment immediately after the hole.
+ iterator advanceTo(iterator I, SlotIndex Pos) {
+ assert(I != end());
+ if (Pos >= endIndex())
return end();
while (I->end <= Pos) ++I;
return I;
}
- void swap(LiveInterval& other) {
- std::swap(reg, other.reg);
- std::swap(weight, other.weight);
- std::swap(remat, other.remat);
- std::swap(ranges, other.ranges);
- std::swap(ValueNumberInfo, other.ValueNumberInfo);
+ const_iterator advanceTo(const_iterator I, SlotIndex Pos) const {
+ assert(I != end());
+ if (Pos >= endIndex())
+ return end();
+ while (I->end <= Pos) ++I;
+ return I;
+ }
+
+ /// find - Return an iterator pointing to the first segment that ends after
+ /// Pos, or end(). This is the same as advanceTo(begin(), Pos), but faster
+ /// when searching large ranges.
+ ///
+ /// If Pos is contained in a Segment, that segment is returned.
+ /// If Pos is in a hole, the following Segment is returned.
+ /// If Pos is beyond endIndex, end() is returned.
+ iterator find(SlotIndex Pos);
+
+ const_iterator find(SlotIndex Pos) const {
+ return const_cast<LiveRange*>(this)->find(Pos);
+ }
+
+ void clear() {
+ valnos.clear();
+ segments.clear();
+ }
+
+ size_t size() const {
+ return segments.size();
}
- bool containsOneValue() const { return ValueNumberInfo.size() == 1; }
+ bool hasAtLeastOneValue() const { return !valnos.empty(); }
+
+ bool containsOneValue() const { return valnos.size() == 1; }
+
+ 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];
+ }
+
+ /// containsValue - Returns true if VNI belongs to this range.
+ bool containsValue(const VNInfo *VNI) const {
+ return VNI && VNI->id < getNumValNums() && VNI == getValNumInfo(VNI->id);
+ }
- unsigned getNumValNums() const { return ValueNumberInfo.size(); }
-
/// getNextValue - Create a new value number and return it. MIIdx specifies
/// the instruction that defines the value number.
- unsigned getNextValue(unsigned MIIdx, unsigned SrcReg) {
- ValueNumberInfo.push_back(VNInfo(MIIdx, ~0U, SrcReg));
- return ValueNumberInfo.size()-1;
+ VNInfo *getNextValue(SlotIndex def, VNInfo::Allocator &VNInfoAllocator) {
+ VNInfo *VNI =
+ new (VNInfoAllocator) VNInfo((unsigned)valnos.size(), def);
+ valnos.push_back(VNI);
+ return VNI;
}
-
- /// getInstForValNum - Return the machine instruction index that defines the
- /// specified value number.
- unsigned getInstForValNum(unsigned ValNo) const {
- //assert(ValNo < ValueNumberInfo.size());
- return ValueNumberInfo[ValNo].def;
+
+ /// createDeadDef - Make sure the range has a value defined at Def.
+ /// If one already exists, return it. Otherwise allocate a new value and
+ /// add liveness for a dead def.
+ VNInfo *createDeadDef(SlotIndex Def, VNInfo::Allocator &VNInfoAllocator);
+
+ /// Create a copy of the given value. The new value will be identical except
+ /// for the Value number.
+ VNInfo *createValueCopy(const VNInfo *orig,
+ VNInfo::Allocator &VNInfoAllocator) {
+ VNInfo *VNI =
+ new (VNInfoAllocator) VNInfo((unsigned)valnos.size(), *orig);
+ valnos.push_back(VNI);
+ return VNI;
}
-
- /// getKillForValNum - Return the machine instruction index that kills the
- /// specified value number.
- unsigned getKillForValNum(unsigned ValNo) const {
- //assert(ValNo < ValueNumberInfo.size());
- return ValueNumberInfo[ValNo].kill;
- }
-
- unsigned getSrcRegForValNum(unsigned ValNo) const {
- //assert(ValNo < ValueNumberInfo.size());
- return ValueNumberInfo[ValNo].reg;
- }
-
- VNInfo getValNumInfo(unsigned ValNo) const {
- //assert(ValNo < ValueNumberInfo.size());
- return ValueNumberInfo[ValNo];
- }
-
- /// setValueNumberInfo - Change the value number info for the specified
- /// value number.
- void setValueNumberInfo(unsigned ValNo, const VNInfo &I) {
- ValueNumberInfo[ValNo] = I;
- }
-
- /// MergeValueNumberInto - This method is called when two value nubmers
+
+ /// RenumberValues - Renumber all values in order of appearance and remove
+ /// unused values.
+ void RenumberValues();
+
+ /// MergeValueNumberInto - This method is called when two value numbers
/// are found to be equivalent. This eliminates V1, replacing all
- /// LiveRanges with the V1 value number with the V2 value number. This can
+ /// segments 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(unsigned V1, unsigned 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.
- void MergeInClobberRanges(const LiveInterval &Clobbers);
+ VNInfo* MergeValueNumberInto(VNInfo *V1, VNInfo *V2);
+
+ /// Merge all of the live segments of a specific val# in RHS into this live
+ /// range as the specified value number. The segments in RHS are allowed
+ /// to overlap with segments in the current range, it will replace the
+ /// value numbers of the overlaped live segments with the specified value
+ /// number.
+ void MergeSegmentsInAsValue(const LiveRange &RHS, VNInfo *LHSValNo);
+
+ /// MergeValueInAsValue - Merge all of the segments of a specific val#
+ /// in RHS into this live range as the specified value number.
+ /// The segments in RHS are allowed to overlap with segments in the
+ /// current range, but only if the overlapping segments have the
+ /// specified value number.
+ void MergeValueInAsValue(const LiveRange &RHS,
+ const VNInfo *RHSValNo, VNInfo *LHSValNo);
-
- /// 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.
- void MergeRangesInAsValue(const LiveInterval &RHS, unsigned LHSValNo);
-
- bool empty() const { return ranges.empty(); }
+ bool empty() const { return segments.empty(); }
- /// beginNumber - Return the lowest numbered slot covered by interval.
- unsigned beginNumber() const {
- assert(!empty() && "empty interval for register");
- return ranges.front().start;
+ /// beginIndex - Return the lowest numbered slot covered.
+ SlotIndex beginIndex() const {
+ assert(!empty() && "Call to beginIndex() on empty range.");
+ return segments.front().start;
}
- /// endNumber - return the maximum point of the interval of the whole,
+ /// endNumber - return the maximum point of the range of the whole,
/// exclusive.
- unsigned endNumber() const {
- assert(!empty() && "empty interval for register");
- return ranges.back().end;
+ SlotIndex endIndex() const {
+ assert(!empty() && "Call to endIndex() on empty range.");
+ return segments.back().end;
+ }
+
+ bool expiredAt(SlotIndex index) const {
+ return index >= endIndex();
+ }
+
+ bool liveAt(SlotIndex index) const {
+ const_iterator r = find(index);
+ return r != end() && r->start <= index;
+ }
+
+ /// Return the segment that contains the specified index, or null if there
+ /// is none.
+ const Segment *getSegmentContaining(SlotIndex Idx) const {
+ const_iterator I = FindSegmentContaining(Idx);
+ return I == end() ? nullptr : &*I;
}
- bool expiredAt(unsigned index) const {
- return index >= endNumber();
+ /// Return the live segment that contains the specified index, or null if
+ /// there is none.
+ Segment *getSegmentContaining(SlotIndex Idx) {
+ iterator I = FindSegmentContaining(Idx);
+ return I == end() ? nullptr : &*I;
}
- bool liveAt(unsigned index) const;
+ /// getVNInfoAt - Return the VNInfo that is live at Idx, or NULL.
+ VNInfo *getVNInfoAt(SlotIndex Idx) const {
+ const_iterator I = FindSegmentContaining(Idx);
+ return I == end() ? nullptr : I->valno;
+ }
- /// getLiveRangeContaining - Return the live range that contains the
- /// specified index, or null if there is none.
- const LiveRange *getLiveRangeContaining(unsigned Idx) const {
- const_iterator I = FindLiveRangeContaining(Idx);
- return I == end() ? 0 : &*I;
+ /// getVNInfoBefore - Return the VNInfo that is live up to but not
+ /// necessarilly including Idx, or NULL. Use this to find the reaching def
+ /// used by an instruction at this SlotIndex position.
+ VNInfo *getVNInfoBefore(SlotIndex Idx) const {
+ const_iterator I = FindSegmentContaining(Idx.getPrevSlot());
+ return I == end() ? nullptr : I->valno;
}
- /// 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;
+ /// Return an iterator to the segment that contains the specified index, or
+ /// end() if there is none.
+ iterator FindSegmentContaining(SlotIndex Idx) {
+ iterator I = find(Idx);
+ return I != end() && I->start <= Idx ? I : end();
+ }
- /// 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);
+ const_iterator FindSegmentContaining(SlotIndex Idx) const {
+ const_iterator I = find(Idx);
+ return I != end() && I->start <= Idx ? I : end();
+ }
- /// overlaps - Return true if the intersection of the two live intervals is
+ /// overlaps - Return true if the intersection of the two live ranges is
/// not empty.
- bool overlaps(const LiveInterval& other) const {
+ bool overlaps(const LiveRange &other) const {
+ if (other.empty())
+ return false;
return overlapsFrom(other, other.begin());
}
- /// overlapsFrom - Return true if the intersection of the two live intervals
+ /// overlaps - Return true if the two ranges have overlapping segments
+ /// that are not coalescable according to CP.
+ ///
+ /// Overlapping segments where one range is defined by a coalescable
+ /// copy are allowed.
+ bool overlaps(const LiveRange &Other, const CoalescerPair &CP,
+ const SlotIndexes&) const;
+
+ /// overlaps - Return true if the live range overlaps an interval specified
+ /// by [Start, End).
+ bool overlaps(SlotIndex Start, SlotIndex End) const;
+
+ /// overlapsFrom - Return true if the intersection of the two live ranges
/// 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;
+ /// scanning the Other range starting at I.
+ bool overlapsFrom(const LiveRange &Other, const_iterator I) const;
+
+ /// Returns true if all segments of the @p Other live range are completely
+ /// covered by this live range.
+ /// Adjacent live ranges do not affect the covering:the liverange
+ /// [1,5](5,10] covers (3,7].
+ bool covers(const LiveRange &Other) const;
+
+ /// Add the specified Segment to this range, merging segments as
+ /// appropriate. This returns an iterator to the inserted segment (which
+ /// may have grown since it was inserted).
+ iterator addSegment(Segment S);
+
+ /// If this range is live before @p Use in the basic block that starts at
+ /// @p StartIdx, extend it to be live up to @p Use, and return the value. If
+ /// there is no segment before @p Use, return nullptr.
+ VNInfo *extendInBlock(SlotIndex StartIdx, SlotIndex Use);
+
+ /// join - Join two live ranges (this, and other) together. This applies
+ /// mappings to the value numbers in the LHS/RHS ranges as specified. If
+ /// the ranges are not joinable, this aborts.
+ void join(LiveRange &Other,
+ const int *ValNoAssignments,
+ const int *RHSValNoAssignments,
+ SmallVectorImpl<VNInfo *> &NewVNInfo);
+
+ /// True iff this segment is a single segment that lies between the
+ /// specified boundaries, exclusively. Vregs live across a backedge are not
+ /// considered local. The boundaries are expected to lie within an extended
+ /// basic block, so vregs that are not live out should contain no holes.
+ bool isLocal(SlotIndex Start, SlotIndex End) const {
+ return beginIndex() > Start.getBaseIndex() &&
+ endIndex() < End.getBoundaryIndex();
+ }
+
+ /// Remove the specified segment from this range. Note that the segment
+ /// must be a single Segment in its entirety.
+ void removeSegment(SlotIndex Start, SlotIndex End,
+ bool RemoveDeadValNo = false);
+
+ void removeSegment(Segment S, bool RemoveDeadValNo = false) {
+ removeSegment(S.start, S.end, RemoveDeadValNo);
+ }
+
+ /// Remove segment pointed to by iterator @p I from this range. This does
+ /// not remove dead value numbers.
+ iterator removeSegment(iterator I) {
+ return segments.erase(I);
+ }
+
+ /// Query Liveness at Idx.
+ /// The sub-instruction slot of Idx doesn't matter, only the instruction
+ /// it refers to is considered.
+ LiveQueryResult Query(SlotIndex Idx) const {
+ // Find the segment that enters the instruction.
+ const_iterator I = find(Idx.getBaseIndex());
+ const_iterator E = end();
+ if (I == E)
+ return LiveQueryResult(nullptr, nullptr, SlotIndex(), false);
+
+ // Is this an instruction live-in segment?
+ // If Idx is the start index of a basic block, include live-in segments
+ // that start at Idx.getBaseIndex().
+ VNInfo *EarlyVal = nullptr;
+ VNInfo *LateVal = nullptr;
+ SlotIndex EndPoint;
+ bool Kill = false;
+ if (I->start <= Idx.getBaseIndex()) {
+ EarlyVal = I->valno;
+ EndPoint = I->end;
+ // Move to the potentially live-out segment.
+ if (SlotIndex::isSameInstr(Idx, I->end)) {
+ Kill = true;
+ if (++I == E)
+ return LiveQueryResult(EarlyVal, LateVal, EndPoint, Kill);
+ }
+ // Special case: A PHIDef value can have its def in the middle of a
+ // segment if the value happens to be live out of the layout
+ // predecessor.
+ // Such a value is not live-in.
+ if (EarlyVal->def == Idx.getBaseIndex())
+ EarlyVal = nullptr;
+ }
+ // I now points to the segment that may be live-through, or defined by
+ // this instr. Ignore segments starting after the current instr.
+ if (!SlotIndex::isEarlierInstr(Idx, I->start)) {
+ LateVal = I->valno;
+ EndPoint = I->end;
+ }
+ return LiveQueryResult(EarlyVal, LateVal, EndPoint, Kill);
+ }
+
+ /// removeValNo - Remove all the segments defined by the specified value#.
+ /// Also remove the value# from value# list.
+ void removeValNo(VNInfo *ValNo);
+
+ /// Returns true if the live range is zero length, i.e. no live segments
+ /// span instructions. It doesn't pay to spill such a range.
+ bool isZeroLength(SlotIndexes *Indexes) const {
+ for (const Segment &S : segments)
+ if (Indexes->getNextNonNullIndex(S.start).getBaseIndex() <
+ S.end.getBaseIndex())
+ return false;
+ return true;
+ }
+
+ bool operator<(const LiveRange& other) const {
+ const SlotIndex &thisIndex = beginIndex();
+ const SlotIndex &otherIndex = other.beginIndex();
+ return thisIndex < otherIndex;
+ }
+
+ /// Flush segment set into the regular segment vector.
+ /// The method is to be called after the live range
+ /// has been created, if use of the segment set was
+ /// activated in the constructor of the live range.
+ void flushSegmentSet();
+
+ void print(raw_ostream &OS) const;
+ void dump() const;
- /// addRange - Add the specified LiveRange to this interval, merging
- /// intervals as appropriate. This returns an iterator to the inserted live
- /// range (which may have grown since it was inserted.
- void addRange(LiveRange LR) {
- addRangeFrom(LR, ranges.begin());
+ /// \brief Walk the range and assert if any invariants fail to hold.
+ ///
+ /// Note that this is a no-op when asserts are disabled.
+#ifdef NDEBUG
+ void verify() const {}
+#else
+ void verify() const;
+#endif
+
+ protected:
+ /// Append a segment to the list of segments.
+ void append(const LiveRange::Segment S);
+
+ private:
+ friend class LiveRangeUpdater;
+ void addSegmentToSet(Segment S);
+ void markValNoForDeletion(VNInfo *V);
+
+ };
+
+ inline raw_ostream &operator<<(raw_ostream &OS, const LiveRange &LR) {
+ LR.print(OS);
+ return OS;
+ }
+
+ /// LiveInterval - This class represents the liveness of a register,
+ /// or stack slot.
+ class LiveInterval : public LiveRange {
+ public:
+ typedef LiveRange super;
+
+ /// A live range for subregisters. The LaneMask specifies which parts of the
+ /// super register are covered by the interval.
+ /// (@sa TargetRegisterInfo::getSubRegIndexLaneMask()).
+ class SubRange : public LiveRange {
+ public:
+ SubRange *Next;
+ unsigned LaneMask;
+
+ /// Constructs a new SubRange object.
+ SubRange(unsigned LaneMask)
+ : Next(nullptr), LaneMask(LaneMask) {
+ }
+
+ /// Constructs a new SubRange object by copying liveness from @p Other.
+ SubRange(unsigned LaneMask, const LiveRange &Other,
+ BumpPtrAllocator &Allocator)
+ : LiveRange(Other, Allocator), Next(nullptr), LaneMask(LaneMask) {
+ }
+ };
+
+ private:
+ SubRange *SubRanges; ///< Single linked list of subregister live ranges.
+
+ public:
+ const unsigned reg; // the register or stack slot of this interval.
+ float weight; // weight of this interval
+
+ LiveInterval(unsigned Reg, float Weight)
+ : SubRanges(nullptr), reg(Reg), weight(Weight) {}
+
+ ~LiveInterval() {
+ clearSubRanges();
}
- /// 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> &NewValueNumberInfo);
+ template<typename T>
+ class SingleLinkedListIterator {
+ T *P;
+ public:
+ SingleLinkedListIterator<T>(T *P) : P(P) {}
+ SingleLinkedListIterator<T> &operator++() {
+ P = P->Next;
+ return *this;
+ }
+ SingleLinkedListIterator<T> &operator++(int) {
+ SingleLinkedListIterator res = *this;
+ ++*this;
+ return res;
+ }
+ bool operator!=(const SingleLinkedListIterator<T> &Other) {
+ return P != Other.operator->();
+ }
+ bool operator==(const SingleLinkedListIterator<T> &Other) {
+ return P == Other.operator->();
+ }
+ T &operator*() const {
+ return *P;
+ }
+ T *operator->() const {
+ return P;
+ }
+ };
+
+ typedef SingleLinkedListIterator<SubRange> subrange_iterator;
+ subrange_iterator subrange_begin() {
+ return subrange_iterator(SubRanges);
+ }
+ subrange_iterator subrange_end() {
+ return subrange_iterator(nullptr);
+ }
- /// 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);
+ typedef SingleLinkedListIterator<const SubRange> const_subrange_iterator;
+ const_subrange_iterator subrange_begin() const {
+ return const_subrange_iterator(SubRanges);
+ }
+ const_subrange_iterator subrange_end() const {
+ return const_subrange_iterator(nullptr);
+ }
- void removeRange(LiveRange LR) {
- removeRange(LR.start, LR.end);
+ iterator_range<subrange_iterator> subranges() {
+ return make_range(subrange_begin(), subrange_end());
}
+ iterator_range<const_subrange_iterator> subranges() const {
+ return make_range(subrange_begin(), subrange_end());
+ }
+
+ /// Creates a new empty subregister live range. The range is added at the
+ /// beginning of the subrange list; subrange iterators stay valid.
+ SubRange *createSubRange(BumpPtrAllocator &Allocator, unsigned LaneMask) {
+ SubRange *Range = new (Allocator) SubRange(LaneMask);
+ appendSubRange(Range);
+ return Range;
+ }
+
+ /// Like createSubRange() but the new range is filled with a copy of the
+ /// liveness information in @p CopyFrom.
+ SubRange *createSubRangeFrom(BumpPtrAllocator &Allocator, unsigned LaneMask,
+ const LiveRange &CopyFrom) {
+ SubRange *Range = new (Allocator) SubRange(LaneMask, CopyFrom, Allocator);
+ appendSubRange(Range);
+ return Range;
+ }
+
+ /// Returns true if subregister liveness information is available.
+ bool hasSubRanges() const {
+ return SubRanges != nullptr;
+ }
+
+ /// Removes all subregister liveness information.
+ void clearSubRanges();
+
+ /// Removes all subranges without any segments (subranges without segments
+ /// are not considered valid and should only exist temporarily).
+ void removeEmptySubRanges();
+
+ /// Construct main live range by merging the SubRanges of @p LI.
+ void constructMainRangeFromSubranges(const SlotIndexes &Indexes,
+ VNInfo::Allocator &VNIAllocator);
+
/// getSize - Returns the sum of sizes of all the LiveRange's.
///
unsigned getSize() const;
- bool operator<(const LiveInterval& other) const {
- return beginNumber() < other.beginNumber();
+ /// isSpillable - Can this interval be spilled?
+ bool isSpillable() const {
+ return weight != llvm::huge_valf;
}
- 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);
+ /// markNotSpillable - Mark interval as not spillable
+ void markNotSpillable() {
+ weight = llvm::huge_valf;
+ }
+
+ bool operator<(const LiveInterval& other) const {
+ const SlotIndex &thisIndex = beginIndex();
+ const SlotIndex &otherIndex = other.beginIndex();
+ return std::tie(thisIndex, reg) < std::tie(otherIndex, other.reg);
}
+
+ void print(raw_ostream &OS) const;
void dump() const;
+ /// \brief Walks the interval and assert if any invariants fail to hold.
+ ///
+ /// Note that this is a no-op when asserts are disabled.
+#ifdef NDEBUG
+ void verify(const MachineRegisterInfo *MRI = nullptr) const {}
+#else
+ void verify(const MachineRegisterInfo *MRI = nullptr) const;
+#endif
+
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
+ /// Appends @p Range to SubRanges list.
+ void appendSubRange(SubRange *Range) {
+ Range->Next = SubRanges;
+ SubRanges = Range;
+ }
+
+ /// Free memory held by SubRange.
+ void freeSubRange(SubRange *S);
};
- inline std::ostream &operator<<(std::ostream &OS, const LiveInterval &LI) {
+ inline raw_ostream &operator<<(raw_ostream &OS, const LiveInterval &LI) {
LI.print(OS);
return OS;
}
-}
+ raw_ostream &operator<<(raw_ostream &OS, const LiveRange::Segment &S);
+
+ inline bool operator<(SlotIndex V, const LiveRange::Segment &S) {
+ return V < S.start;
+ }
+
+ inline bool operator<(const LiveRange::Segment &S, SlotIndex V) {
+ return S.start < V;
+ }
+
+ /// Helper class for performant LiveRange bulk updates.
+ ///
+ /// Calling LiveRange::addSegment() repeatedly can be expensive on large
+ /// live ranges because segments after the insertion point may need to be
+ /// shifted. The LiveRangeUpdater class can defer the shifting when adding
+ /// many segments in order.
+ ///
+ /// The LiveRange will be in an invalid state until flush() is called.
+ class LiveRangeUpdater {
+ LiveRange *LR;
+ SlotIndex LastStart;
+ LiveRange::iterator WriteI;
+ LiveRange::iterator ReadI;
+ SmallVector<LiveRange::Segment, 16> Spills;
+ void mergeSpills();
+
+ public:
+ /// Create a LiveRangeUpdater for adding segments to LR.
+ /// LR will temporarily be in an invalid state until flush() is called.
+ LiveRangeUpdater(LiveRange *lr = nullptr) : LR(lr) {}
+
+ ~LiveRangeUpdater() { flush(); }
+
+ /// Add a segment to LR and coalesce when possible, just like
+ /// LR.addSegment(). Segments should be added in increasing start order for
+ /// best performance.
+ void add(LiveRange::Segment);
+
+ void add(SlotIndex Start, SlotIndex End, VNInfo *VNI) {
+ add(LiveRange::Segment(Start, End, VNI));
+ }
+
+ /// Return true if the LR is currently in an invalid state, and flush()
+ /// needs to be called.
+ bool isDirty() const { return LastStart.isValid(); }
+
+ /// Flush the updater state to LR so it is valid and contains all added
+ /// segments.
+ void flush();
+
+ /// Select a different destination live range.
+ void setDest(LiveRange *lr) {
+ if (LR != lr && isDirty())
+ flush();
+ LR = lr;
+ }
+
+ /// Get the current destination live range.
+ LiveRange *getDest() const { return LR; }
+
+ void dump() const;
+ void print(raw_ostream&) const;
+ };
+
+ inline raw_ostream &operator<<(raw_ostream &OS, const LiveRangeUpdater &X) {
+ X.print(OS);
+ return OS;
+ }
+
+ /// ConnectedVNInfoEqClasses - Helper class that can divide VNInfos in a
+ /// LiveInterval into equivalence clases of connected components. A
+ /// LiveInterval that has multiple connected components can be broken into
+ /// multiple LiveIntervals.
+ ///
+ /// Given a LiveInterval that may have multiple connected components, run:
+ ///
+ /// unsigned numComps = ConEQ.Classify(LI);
+ /// if (numComps > 1) {
+ /// // allocate numComps-1 new LiveIntervals into LIS[1..]
+ /// ConEQ.Distribute(LIS);
+ /// }
+
+ class ConnectedVNInfoEqClasses {
+ LiveIntervals &LIS;
+ IntEqClasses EqClass;
+
+ // Note that values a and b are connected.
+ void Connect(unsigned a, unsigned b);
+
+ unsigned Renumber();
+
+ public:
+ explicit ConnectedVNInfoEqClasses(LiveIntervals &lis) : LIS(lis) {}
+
+ /// Classify - Classify the values in LI into connected components.
+ /// Return the number of connected components.
+ unsigned Classify(const LiveInterval *LI);
+
+ /// getEqClass - Classify creates equivalence classes numbered 0..N. Return
+ /// the equivalence class assigned the VNI.
+ unsigned getEqClass(const VNInfo *VNI) const { return EqClass[VNI->id]; }
+
+ /// Distribute - Distribute values in LIV[0] into a separate LiveInterval
+ /// for each connected component. LIV must have a LiveInterval for each
+ /// connected component. The LiveIntervals in Liv[1..] must be empty.
+ /// Instructions using LIV[0] are rewritten.
+ void Distribute(LiveInterval *LIV[], MachineRegisterInfo &MRI);
+
+ };
+
+}
#endif
projects / oota-llvm.git / blobdiff