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"
25 #include "llvm/CodeGen/MachineBasicBlock.h"
34 class LiveIntervals : public MachineFunctionPass
38 typedef std::pair<unsigned, unsigned> Range;
39 typedef std::vector<Range> Ranges;
40 unsigned reg; // the register of this interval
41 Ranges ranges; // the ranges this register is valid
48 unsigned start() const {
49 assert(!ranges.empty() && "empty interval for register");
50 return ranges.front().first;
53 unsigned end() const {
54 assert(!ranges.empty() && "empty interval for register");
55 return ranges.back().second;
58 bool expired(unsigned index) const {
59 return end() <= index;
62 void addRange(unsigned start, unsigned end);
65 void mergeRangesForward(Ranges::iterator it);
67 void mergeRangesBackward(Ranges::iterator it);
70 struct StartPointComp {
71 bool operator()(const Interval& lhs, const Interval& rhs) {
72 return lhs.ranges.front().first < rhs.ranges.front().first;
77 bool operator()(const Interval& lhs, const Interval& rhs) {
78 return lhs.ranges.back().second < rhs.ranges.back().second;
82 typedef std::vector<Interval> Intervals;
83 typedef std::vector<MachineBasicBlock*> MachineBasicBlockPtrs;
87 const TargetMachine* tm_;
88 const MRegisterInfo* mri_;
89 MachineBasicBlock* currentMbb_;
90 MachineBasicBlock::iterator currentInstr_;
93 std::vector<bool> allocatableRegisters_;
95 typedef std::map<unsigned, MachineBasicBlock*> MbbIndex2MbbMap;
96 MbbIndex2MbbMap mbbi2mbbMap_;
98 typedef std::map<MachineInstr*, unsigned> Mi2IndexMap;
101 typedef std::map<unsigned, unsigned> Reg2IntervalMap;
102 Reg2IntervalMap r2iMap_;
104 Intervals intervals_;
107 virtual void getAnalysisUsage(AnalysisUsage &AU) const;
108 Intervals& getIntervals() { return intervals_; }
109 MachineBasicBlockPtrs getOrderedMachineBasicBlockPtrs() const {
110 MachineBasicBlockPtrs result;
111 for (MbbIndex2MbbMap::const_iterator
112 it = mbbi2mbbMap_.begin(), itEnd = mbbi2mbbMap_.end();
114 result.push_back(it->second);
120 /// runOnMachineFunction - pass entry point
121 bool runOnMachineFunction(MachineFunction&);
123 /// computeIntervals - compute live intervals
124 void computeIntervals();
127 /// handleRegisterDef - update intervals for a register def
128 /// (calls handlePhysicalRegisterDef and
129 /// handleVirtualRegisterDef)
130 void handleRegisterDef(MachineBasicBlock* mbb,
131 MachineBasicBlock::iterator mi,
134 /// handleVirtualRegisterDef - update intervals for a virtual
136 void handleVirtualRegisterDef(MachineBasicBlock* mbb,
137 MachineBasicBlock::iterator mi,
140 /// handlePhysicalRegisterDef - update intervals for a
141 /// physical register def
142 void handlePhysicalRegisterDef(MachineBasicBlock* mbb,
143 MachineBasicBlock::iterator mi,
146 unsigned getInstructionIndex(MachineInstr* instr) const;
148 void printRegName(unsigned reg) const;
151 inline bool operator==(const LiveIntervals::Interval& lhs,
152 const LiveIntervals::Interval& rhs) {
153 return lhs.reg == rhs.reg;
156 std::ostream& operator<<(std::ostream& os,
157 const LiveIntervals::Interval& li);
159 } // End llvm namespace