#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 "llvm/ADT/IntEqClasses.h"
#include "llvm/CodeGen/SlotIndexes.h"
+#include "llvm/Support/AlignOf.h"
+#include "llvm/Support/Allocator.h"
#include <cassert>
#include <climits>
namespace llvm {
+ class CoalescerPair;
class LiveIntervals;
class MachineInstr;
class MachineRegisterInfo;
/// definition and use points.
///
class VNInfo {
- private:
- enum {
- HAS_PHI_KILL = 1,
- REDEF_BY_EC = 1 << 1,
- IS_PHI_DEF = 1 << 2,
- IS_UNUSED = 1 << 3
- };
-
- MachineInstr *copy;
- unsigned char flags;
-
public:
typedef BumpPtrAllocator Allocator;
/// The ID number of this value.
unsigned id;
- /// The index of the defining instruction (if isDefAccurate() returns true).
+ /// The index of the defining instruction.
SlotIndex def;
/// VNInfo constructor.
- VNInfo(unsigned i, SlotIndex d, MachineInstr *c)
- : copy(c), flags(0), id(i), def(d)
+ VNInfo(unsigned i, SlotIndex d)
+ : id(i), def(d)
{ }
/// VNInfo construtor, copies values from orig, except for the value number.
VNInfo(unsigned i, const VNInfo &orig)
- : copy(orig.copy), flags(orig.flags), id(i), def(orig.def)
+ : id(i), def(orig.def)
{ }
/// Copy from the parameter into this VNInfo.
void copyFrom(VNInfo &src) {
- flags = src.flags;
- copy = src.copy;
def = src.def;
}
- /// Used for copying value number info.
- unsigned getFlags() const { return flags; }
- void setFlags(unsigned flags) { this->flags = flags; }
-
- /// Merge flags from another VNInfo
- void mergeFlags(const VNInfo *VNI) {
- flags = (flags | VNI->flags) & ~IS_UNUSED;
- }
-
- /// For a register interval, if this VN was definied by a copy instr
- /// getCopy() returns a pointer to it, otherwise returns 0.
- /// For a stack interval the behaviour of this method is undefined.
- MachineInstr* getCopy() const { return copy; }
- /// For a register interval, set the copy member.
- /// This method should not be called on stack intervals as it may lead to
- /// undefined behavior.
- void setCopy(MachineInstr *c) { copy = c; }
-
- /// isDefByCopy - Return true when this value was defined by a copy-like
- /// instruction as determined by MachineInstr::isCopyLike.
- bool isDefByCopy() const { return copy != 0; }
-
- /// Returns true if one or more kills are PHI nodes.
- bool hasPHIKill() const { return flags & HAS_PHI_KILL; }
- /// Set the PHI kill flag on this value.
- 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; }
- /// Set the "redef by early clobber" flag on this value.
- 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; }
- /// Set the "phi def" flag on this value.
- void setIsPHIDef(bool phiDef) {
- if (phiDef)
- flags |= IS_PHI_DEF;
- else
- flags &= ~IS_PHI_DEF;
- }
+ /// PHI-defs begin at a block boundary, all other defs begin at register or
+ /// EC slots.
+ bool isPHIDef() const { return def.isBlock(); }
/// Returns true if this value is unused.
- bool isUnused() const { return flags & IS_UNUSED; }
- /// Set the "is unused" flag on this value.
- void setIsUnused(bool unused) {
- if (unused)
- flags |= IS_UNUSED;
- else
- flags &= ~IS_UNUSED;
- }
+ bool isUnused() const { return !def.isValid(); }
+
+ /// Mark this value as unused.
+ void markUnused() { def = SlotIndex(); }
};
/// LiveRange structure - This represents a simple register range in the
void dump() const;
void print(raw_ostream &os) const;
-
- private:
- LiveRange(); // DO NOT IMPLEMENT
};
template <> struct isPodLike<LiveRange> { static const bool value = true; };
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.
+ const unsigned reg; // the register or stack slot of this interval.
float weight; // weight of this interval
Ranges ranges; // the ranges in which this register is live
VNInfoList valnos; // value#'s
};
- LiveInterval(unsigned Reg, float Weight, bool IsSS = false)
- : reg(Reg), weight(Weight) {
- if (IsSS)
- reg = reg | (1U << (sizeof(unsigned)*CHAR_BIT-1));
- }
+ LiveInterval(unsigned Reg, float Weight)
+ : reg(Reg), weight(Weight) {}
typedef Ranges::iterator iterator;
iterator begin() { return ranges.begin(); }
/// position is in a hole, this method returns an iterator pointing to the
/// LiveRange immediately after the hole.
iterator advanceTo(iterator I, SlotIndex Pos) {
+ assert(I != end());
if (Pos >= endIndex())
return end();
while (I->end <= Pos) ++I;
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; }
return valnos[ValNo];
}
+ /// containsValue - Returns true if VNI belongs to this interval.
+ bool containsValue(const VNInfo *VNI) const {
+ return VNI && VNI->id < getNumValNums() && VNI == getValNumInfo(VNI->id);
+ }
+
/// getNextValue - Create a new value number and return it. MIIdx specifies
/// the instruction that defines the value number.
- VNInfo *getNextValue(SlotIndex def, MachineInstr *CopyMI,
- VNInfo::Allocator &VNInfoAllocator) {
+ VNInfo *getNextValue(SlotIndex def, VNInfo::Allocator &VNInfoAllocator) {
VNInfo *VNI =
- new (VNInfoAllocator) VNInfo((unsigned)valnos.size(), def, CopyMI);
+ new (VNInfoAllocator) VNInfo((unsigned)valnos.size(), def);
valnos.push_back(VNI);
return VNI;
}
+ /// createDeadDef - Make sure the interval 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,
/// RenumberValues - Renumber all values in order of appearance and remove
/// unused values.
- /// Recalculate phi-kill flags in case any phi-def values were removed.
void RenumberValues(LiveIntervals &lis);
- /// 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
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,
- VNInfo::Allocator &VNInfoAllocator);
-
bool empty() const { return ranges.empty(); }
/// beginIndex - Return the lowest numbered slot covered by interval.
/// point is not contained in the half-open live range. It is usually the
/// getDefIndex() slot following its last use.
bool killedAt(SlotIndex index) const {
- const_iterator r = find(index.getUseIndex());
+ const_iterator r = find(index.getRegSlot(true));
return r != end() && r->end == index;
}
- /// killedInRange - Return true if the interval has kills in [Start,End).
- /// Note that the kill point is considered the end of a live range, so it is
- /// not contained in the live range. If a live range ends at End, it won't
- /// be counted as a kill by this method.
- bool killedInRange(SlotIndex Start, SlotIndex End) const;
-
/// getLiveRangeContaining - Return the live range that contains the
/// specified index, or null if there is none.
const LiveRange *getLiveRangeContaining(SlotIndex Idx) const {
return I == end() ? 0 : I->valno;
}
+ /// 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 = FindLiveRangeContaining(Idx.getPrevSlot());
+ return I == end() ? 0 : I->valno;
+ }
+
/// FindLiveRangeContaining - Return an iterator to the live range that
/// contains the specified index, or end() if there is none.
iterator FindLiveRangeContaining(SlotIndex Idx) {
return I != end() && I->start <= Idx ? I : end();
}
- /// findDefinedVNInfo - Find the by the specified
- /// index (register interval) or defined
- VNInfo *findDefinedVNInfoForRegInt(SlotIndex Idx) 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 two intervals have overlapping segments
+ /// that are not coalescable according to CP.
+ ///
+ /// Overlapping segments where one interval is defined by a coalescable
+ /// copy are allowed.
+ bool overlaps(const LiveInterval &Other, const CoalescerPair &CP,
+ const SlotIndexes&) const;
+
/// overlaps - Return true if the live interval overlaps a range specified
/// by [Start, End).
bool overlaps(SlotIndex Start, SlotIndex End) const;
addRangeFrom(LR, ranges.begin());
}
+ /// extendInBlock - If this interval is live before Kill in the basic block
+ /// that starts at StartIdx, extend it to be live up to Kill, and return
+ /// the value. If there is no live range before Kill, return NULL.
+ VNInfo *extendInBlock(SlotIndex StartIdx, SlotIndex Kill);
+
/// 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.
/// Returns true if the live interval is zero length, i.e. no live ranges
/// span instructions. It doesn't pay to spill such an interval.
- bool isZeroLength() const {
+ bool isZeroLength(SlotIndexes *Indexes) const {
for (const_iterator i = begin(), e = end(); i != e; ++i)
- if (i->end.getPrevIndex() > i->start)
+ if (Indexes->getNextNonNullIndex(i->start).getBaseIndex() <
+ i->end.getBaseIndex())
return false;
return true;
}
weight = HUGE_VALF;
}
- /// ComputeJoinedWeight - Set the weight of a live interval after
- /// Other has been merged into it.
- void ComputeJoinedWeight(const LiveInterval &Other);
-
bool operator<(const LiveInterval& other) const {
const SlotIndex &thisIndex = beginIndex();
const SlotIndex &otherIndex = other.beginIndex();
(thisIndex == otherIndex && reg < other.reg));
}
- void print(raw_ostream &OS, const TargetRegisterInfo *TRI = 0) const;
+ void print(raw_ostream &OS) const;
void dump() const;
+ /// \brief Walk 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 {}
+#else
+ void verify() const;
+#endif
+
private:
Ranges::iterator addRangeFrom(LiveRange LR, Ranges::iterator From);
void extendIntervalEndTo(Ranges::iterator I, SlotIndex NewEnd);
Ranges::iterator extendIntervalStartTo(Ranges::iterator I, SlotIndex NewStr);
void markValNoForDeletion(VNInfo *V);
+ void mergeIntervalRanges(const LiveInterval &RHS,
+ VNInfo *LHSValNo = 0,
+ const VNInfo *RHSValNo = 0);
- LiveInterval& operator=(const LiveInterval& rhs); // DO NOT IMPLEMENT
+ LiveInterval& operator=(const LiveInterval& rhs) LLVM_DELETED_FUNCTION;
};
LI.print(OS);
return OS;
}
-}
+ /// LiveRangeQuery - Query information about a live range around a given
+ /// instruction. 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 LiveRangeQuery {
+ VNInfo *EarlyVal;
+ VNInfo *LateVal;
+ SlotIndex EndPoint;
+ bool Kill;
+
+ public:
+ /// Create a LiveRangeQuery for the given live range and instruction index.
+ /// The sub-instruction slot of Idx doesn't matter, only the instruction it
+ /// refers to is considered.
+ LiveRangeQuery(const LiveInterval &LI, SlotIndex Idx)
+ : EarlyVal(0), LateVal(0), Kill(false) {
+ // Find the segment that enters the instruction.
+ LiveInterval::const_iterator I = LI.find(Idx.getBaseIndex());
+ LiveInterval::const_iterator E = LI.end();
+ if (I == E)
+ return;
+ // 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().
+ 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;
+ }
+ // 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 = 0;
+ }
+ // 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))
+ return;
+ LateVal = I->valno;
+ EndPoint = I->end;
+ }
+
+ /// 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;
+ }
+
+ /// 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;
+ }
+
+ /// Return true if this instruction has a dead def.
+ bool isDeadDef() const {
+ return EndPoint.isDead();
+ }
+
+ /// 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() ? 0 : LateVal;
+ }
+
+ /// 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 ? 0 : LateVal;
+ }
+
+ /// 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;
+ }
+ };
+
+ /// 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