1 //===-- llvm/CodeGen/LiveInterval.h - Live Interval Analysis ----*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the LiveInterval analysis pass. Given some
11 // numbering of each the machine instructions (in this implemention
12 // depth-first order) an interval [i, j) is said to be a live interval
13 // for register v if there is no instruction with number j' > j such
14 // that v is live at j' abd there is no instruction with number i' < i
15 // such that v is live at i'. In this implementation intervals can
16 // have holes, i.e. an interval might look like [1,20), [50,65),
19 //===----------------------------------------------------------------------===//
21 #ifndef LLVM_CODEGEN_LIVEINTERVALS_H
22 #define LLVM_CODEGEN_LIVEINTERVALS_H
24 #include "llvm/CodeGen/MachineFunctionPass.h"
32 class LiveIntervals : public MachineFunctionPass
36 typedef std::pair<unsigned, unsigned> Range;
37 typedef std::vector<Range> Ranges;
38 unsigned reg; // the register of this interval
39 float weight; // weight of this interval (number of uses
41 Ranges ranges; // the ranges in which this register is live
45 bool empty() const { return ranges.empty(); }
49 unsigned start() const {
50 assert(!empty() && "empty interval for register");
51 return ranges.front().first;
54 unsigned end() const {
55 assert(!empty() && "empty interval for register");
56 return ranges.back().second;
59 bool expiredAt(unsigned index) const {
60 return end() <= (index + 1);
63 bool liveAt(unsigned index) const;
65 bool overlaps(const Interval& other) const;
67 void addRange(unsigned start, unsigned end);
69 void join(const Interval& other);
72 Ranges::iterator mergeRangesForward(Ranges::iterator it);
74 Ranges::iterator mergeRangesBackward(Ranges::iterator it);
77 struct StartPointComp {
78 bool operator()(const Interval& lhs, const Interval& rhs) {
79 return lhs.ranges.front().first < rhs.ranges.front().first;
84 bool operator()(const Interval& lhs, const Interval& rhs) {
85 return lhs.ranges.back().second < rhs.ranges.back().second;
89 typedef std::list<Interval> Intervals;
93 const TargetMachine* tm_;
94 const MRegisterInfo* mri_;
95 MachineBasicBlock* currentMbb_;
96 MachineBasicBlock::iterator currentInstr_;
99 typedef std::map<unsigned, MachineBasicBlock*> MbbIndex2MbbMap;
100 MbbIndex2MbbMap mbbi2mbbMap_;
102 typedef std::map<MachineInstr*, unsigned> Mi2IndexMap;
103 Mi2IndexMap mi2iMap_;
105 typedef std::vector<MachineInstr*> Index2MiMap;
106 Index2MiMap i2miMap_;
108 typedef std::map<unsigned, Intervals::iterator> Reg2IntervalMap;
109 Reg2IntervalMap r2iMap_;
111 typedef std::map<unsigned, unsigned> Reg2RegMap;
114 Intervals intervals_;
128 static unsigned getBaseIndex(unsigned index) {
129 return index - (index % InstrSlots::NUM);
131 static unsigned getBoundaryIndex(unsigned index) {
132 return getBaseIndex(index + InstrSlots::NUM - 1);
134 static unsigned getLoadIndex(unsigned index) {
135 return getBaseIndex(index) + InstrSlots::LOAD;
137 static unsigned getUseIndex(unsigned index) {
138 return getBaseIndex(index) + InstrSlots::USE;
140 static unsigned getDefIndex(unsigned index) {
141 return getBaseIndex(index) + InstrSlots::DEF;
143 static unsigned getStoreIndex(unsigned index) {
144 return getBaseIndex(index) + InstrSlots::STORE;
147 virtual void getAnalysisUsage(AnalysisUsage &AU) const;
148 virtual void releaseMemory();
150 /// runOnMachineFunction - pass entry point
151 virtual bool runOnMachineFunction(MachineFunction&);
153 Interval& getInterval(unsigned reg) {
154 assert(r2iMap_.count(reg)&& "Interval does not exist for register");
155 return *r2iMap_.find(reg)->second;
158 /// getInstructionIndex - returns the base index of instr
159 unsigned getInstructionIndex(MachineInstr* instr) const;
161 /// getInstructionFromIndex - given an index in any slot of an
162 /// instruction return a pointer the instruction
163 MachineInstr* getInstructionFromIndex(unsigned index) const;
165 Intervals& getIntervals() { return intervals_; }
167 void updateSpilledInterval(Interval& i, int slot);
170 /// computeIntervals - compute live intervals
171 void computeIntervals();
173 /// joinIntervals - join compatible live intervals
174 void joinIntervals();
176 /// handleRegisterDef - update intervals for a register def
177 /// (calls handlePhysicalRegisterDef and
178 /// handleVirtualRegisterDef)
179 void handleRegisterDef(MachineBasicBlock* mbb,
180 MachineBasicBlock::iterator mi,
183 /// handleVirtualRegisterDef - update intervals for a virtual
185 void handleVirtualRegisterDef(MachineBasicBlock* mbb,
186 MachineBasicBlock::iterator mi,
189 /// handlePhysicalRegisterDef - update intervals for a
190 /// physical register def
191 void handlePhysicalRegisterDef(MachineBasicBlock* mbb,
192 MachineBasicBlock::iterator mi,
195 bool overlapsAliases(const Interval& lhs, const Interval& rhs) const;
197 /// rep - returns the representative of this register
198 unsigned rep(unsigned reg);
200 void printRegName(unsigned reg) const;
203 inline bool operator==(const LiveIntervals::Interval& lhs,
204 const LiveIntervals::Interval& rhs) {
205 return lhs.reg == rhs.reg;
208 std::ostream& operator<<(std::ostream& os,
209 const LiveIntervals::Interval& li);
211 } // End llvm namespace