X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FCodeGen%2FLiveInterval.h;h=95760758deca5c67f737f94262e00ad34a4b3419;hb=980bddfb1c26e2e9374d1645f9ae26c44742606f;hp=ff1dbc2775284cc45f4f97ba617b6f89f4e2a744;hpb=1b2932024f098a6968645ac78d5848951d877c19;p=oota-llvm.git diff --git a/include/llvm/CodeGen/LiveInterval.h b/include/llvm/CodeGen/LiveInterval.h index ff1dbc27752..95760758dec 100644 --- a/include/llvm/CodeGen/LiveInterval.h +++ b/include/llvm/CodeGen/LiveInterval.h @@ -21,14 +21,15 @@ #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 #include namespace llvm { + class CoalescerPair; class LiveIntervals; class MachineInstr; class MachineRegisterInfo; @@ -39,133 +40,42 @@ namespace llvm { /// 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; - union { - MachineInstr *copy; - unsigned reg; - } cr; - 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. - /// d is presumed to point to the actual defining instr. If it doesn't - /// setIsDefAccurate(false) should be called after construction. - VNInfo(unsigned i, SlotIndex d, MachineInstr *c) - : flags(IS_DEF_ACCURATE), id(i), def(d) { cr.copy = c; } + 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) - : flags(orig.flags), cr(orig.cr), id(i), def(orig.def) + : id(i), def(orig.def) { } /// Copy from the parameter into this VNInfo. void copyFrom(VNInfo &src) { - flags = src.flags; - cr = src.cr; def = src.def; } - /// Used for copying value number info. - unsigned getFlags() const { return flags; } - void setFlags(unsigned flags) { this->flags = flags; } - - /// 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 cr.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) { cr.copy = c; } - - /// For a stack interval, returns the reg which this stack interval was - /// defined from. - /// For a register interval the behaviour of this method is undefined. - unsigned getReg() const { return cr.reg; } - /// For a stack interval, set the defining register. - /// This method should not be called on register intervals as it may lead - /// to undefined behaviour. - void setReg(unsigned reg) { cr.reg = reg; } - - /// 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; - } - - /// Returns true if the def is accurate. - bool isDefAccurate() const { return flags & IS_DEF_ACCURATE; } - /// Set the "is def accurate" flag on this value. - void setIsDefAccurate(bool defAccurate) { - if (defAccurate) - flags |= IS_DEF_ACCURATE; - else - flags &= ~IS_DEF_ACCURATE; - } + 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 @@ -204,9 +114,6 @@ namespace llvm { void dump() const; void print(raw_ostream &os) const; - - private: - LiveRange(); // DO NOT IMPLEMENT }; template <> struct isPodLike { static const bool value = true; }; @@ -231,8 +138,7 @@ namespace llvm { typedef SmallVector Ranges; typedef SmallVector 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 @@ -248,11 +154,8 @@ namespace llvm { }; - 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(); } @@ -276,28 +179,29 @@ namespace llvm { /// 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; return I; } - void clear() { - valnos.clear(); - ranges.clear(); - } - - /// isStackSlot - Return true if this is a stack slot interval. + /// find - Return an iterator pointing to the first range that ends after + /// Pos, or end(). This is the same as advanceTo(begin(), Pos), but faster + /// when searching large intervals. /// - bool isStackSlot() const { - return reg & (1U << (sizeof(unsigned)*CHAR_BIT-1)); + /// If Pos is contained in a LiveRange, that range is returned. + /// If Pos is in a hole, the following LiveRange is returned. + /// If Pos is beyond endIndex, end() is returned. + iterator find(SlotIndex Pos); + + const_iterator find(SlotIndex Pos) const { + return const_cast(this)->find(Pos); } - /// 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)); + void clear() { + valnos.clear(); + ranges.clear(); } bool hasAtLeastOneValue() const { return !valnos.empty(); } @@ -315,17 +219,25 @@ namespace llvm { 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, - bool isDefAccurate, VNInfo::Allocator &VNInfoAllocator) { + VNInfo *getNextValue(SlotIndex def, VNInfo::Allocator &VNInfoAllocator) { VNInfo *VNI = - new (VNInfoAllocator) VNInfo((unsigned)valnos.size(), def, CopyMI); - VNI->setIsDefAccurate(isDefAccurate); + 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, @@ -338,18 +250,7 @@ namespace llvm { /// RenumberValues - Renumber all values in order of appearance and remove /// unused values. - void RenumberValues(); - - /// 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; - } + void RenumberValues(LiveIntervals &lis); /// MergeValueNumberInto - This method is called when two value nubmers /// are found to be equivalent. This eliminates V1, replacing all @@ -357,21 +258,6 @@ namespace llvm { /// 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(LiveIntervals &li_, - const LiveInterval &Clobbers, - VNInfo::Allocator &VNInfoAllocator); - - /// MergeInClobberRange - Same as MergeInClobberRanges except it merge in a - /// single LiveRange only. - void MergeInClobberRange(LiveIntervals &li_, - SlotIndex Start, - SlotIndex End, - VNInfo::Allocator &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 @@ -387,11 +273,6 @@ namespace llvm { 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. @@ -411,23 +292,18 @@ namespace llvm { return index >= endIndex(); } - bool liveAt(SlotIndex 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(SlotIndex index) const; + bool liveAt(SlotIndex index) const { + const_iterator r = find(index); + return r != end() && r->start <= index; + } /// killedAt - Return true if a live range ends at index. Note that the kill /// 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; - - /// 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; + bool killedAt(SlotIndex index) const { + const_iterator r = find(index.getRegSlot(true)); + return r != end() && r->end == index; + } /// getLiveRangeContaining - Return the live range that contains the /// specified index, or null if there is none. @@ -449,22 +325,25 @@ namespace llvm { 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. - const_iterator FindLiveRangeContaining(SlotIndex Idx) const; + /// 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); - - /// findDefinedVNInfo - Find the by the specified - /// index (register interval) or defined - VNInfo *findDefinedVNInfoForRegInt(SlotIndex Idx) const; - - /// findDefinedVNInfo - Find the VNInfo that's defined by the specified - /// register (stack inteval only). - VNInfo *findDefinedVNInfoForStackInt(unsigned Reg) const; + iterator FindLiveRangeContaining(SlotIndex Idx) { + iterator I = find(Idx); + return I != end() && I->start <= Idx ? I : end(); + } + const_iterator FindLiveRangeContaining(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 /// not empty. @@ -474,6 +353,14 @@ namespace llvm { 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; @@ -490,6 +377,11 @@ namespace llvm { 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. @@ -501,7 +393,10 @@ namespace llvm { /// isInOneLiveRange - Return true if the range specified is entirely in the /// a single LiveRange of the live interval. - bool isInOneLiveRange(SlotIndex Start, SlotIndex End); + bool isInOneLiveRange(SlotIndex Start, SlotIndex End) const { + const_iterator r = find(Start); + return r != end() && r->containsRange(Start, End); + } /// removeRange - Remove the specified range from this interval. Note that /// the range must be a single LiveRange in its entirety. @@ -522,9 +417,10 @@ namespace llvm { /// 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; } @@ -539,10 +435,6 @@ namespace llvm { 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(); @@ -550,17 +442,29 @@ namespace llvm { (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; }; @@ -568,6 +472,140 @@ namespace llvm { 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