//===-- llvm/CodeGen/LiveInterval.h - Interval representation ---*- C++ -*-===// // // 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 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 // 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. // //===----------------------------------------------------------------------===// #ifndef LLVM_CODEGEN_LIVEINTERVAL_H #define LLVM_CODEGEN_LIVEINTERVAL_H #include "llvm/ADT/SmallVector.h" #include "llvm/Support/Streams.h" #include #include #include namespace llvm { class MRegisterInfo; /// 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. LiveRange(unsigned S, unsigned E, unsigned V) : start(S), end(E), ValId(V) { assert(S < E && "Cannot create empty or backwards range"); } /// contains - Return true if the index is covered by this range. /// bool contains(unsigned I) const { return start <= I && I < end; } 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; } void dump() const; void print(std::ostream &os) const; void print(std::ostream *os) const { if (os) print(*os); } private: LiveRange(); // DO NOT IMPLEMENT }; std::ostream& operator<<(std::ostream& os, const LiveRange &LR); inline bool operator<(unsigned V, const LiveRange &LR) { return V < LR.start; } inline bool operator<(const LiveRange &LR, unsigned V) { return LR.start < V; } /// LiveInterval - This class represents some number of live ranges for a /// register or value. This class also contains a bit of register allocator /// state. struct LiveInterval { typedef SmallVector Ranges; unsigned reg; // the register of this interval float weight; // weight of this interval Ranges ranges; // the ranges in which this register is live private: /// ValueNumberInfo - If this value number is not defined by a copy, this /// holds ~0,x. If the value number is not in use, it contains ~1,x to /// indicate that the value # is not used. If the val# is defined by a /// copy, the first entry is the instruction # of the copy, and the second /// is the register number copied from. SmallVector, 4> ValueNumberInfo; public: LiveInterval(unsigned Reg, float Weight) : reg(Reg), weight(Weight) { } typedef Ranges::iterator iterator; iterator begin() { return ranges.begin(); } iterator end() { return ranges.end(); } typedef Ranges::const_iterator const_iterator; const_iterator begin() const { return ranges.begin(); } const_iterator end() const { return ranges.end(); } /// advanceTo - Advance the specified iterator to point to the LiveRange /// containing the specified position, or end() if the position is past the /// end of the interval. If no LiveRange contains this position, but the /// position is in a hole, this method returns an iterator pointing the the /// LiveRange immediately after the hole. iterator advanceTo(iterator I, unsigned Pos) { if (Pos >= endNumber()) return end(); while (I->end <= Pos) ++I; return I; } void swap(LiveInterval& other) { std::swap(reg, other.reg); std::swap(weight, other.weight); std::swap(ranges, other.ranges); std::swap(ValueNumberInfo, other.ValueNumberInfo); } bool containsOneValue() const { return ValueNumberInfo.size() == 1; } 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(std::make_pair(MIIdx, SrcReg)); return ValueNumberInfo.size()-1; } /// getInstForValNum - Return the machine instruction index that defines the /// specified value number. unsigned getInstForValNum(unsigned ValNo) const { //assert(ValNo < ValueNumberInfo.size()); return ValueNumberInfo[ValNo].first; } unsigned getSrcRegForValNum(unsigned ValNo) const { //assert(ValNo < ValueNumberInfo.size()); if (ValueNumberInfo[ValNo].first < ~2U) return ValueNumberInfo[ValNo].second; return 0; } std::pair 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 std::pair &I){ ValueNumberInfo[ValNo] = I; } /// 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(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); /// 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(); } /// beginNumber - Return the lowest numbered slot covered by interval. unsigned beginNumber() const { assert(!empty() && "empty interval for register"); 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"); return ranges.back().end; } bool expiredAt(unsigned index) const { return index >= endNumber(); } bool liveAt(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 { const_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 &Ranges); /// 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()); } /// overlapsFrom - Return true if the intersection of the two live intervals /// is not empty. The specified iterator is a hint that we can begin /// scanning the Other interval starting at I. bool overlapsFrom(const LiveInterval& other, const_iterator I) const; /// addRange - Add the specified LiveRange to this interval, merging /// intervals as appropriate. This returns an iterator to the inserted live /// range (which may have grown since it was inserted. void addRange(LiveRange LR) { addRangeFrom(LR, ranges.begin()); } /// 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,16> &NewValueNumberInfo); /// 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); void removeRange(LiveRange LR) { removeRange(LR.start, LR.end); } bool operator<(const LiveInterval& other) 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 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) { LI.print(OS); return OS; } } #endif