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//===-- llvm/CodeGen/LiveInterval.h - Live Interval Analysis ----*- 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 LiveInterval analysis pass. Given some
// numbering of each the machine instructions (in this implemention
// depth-first order) 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' abd 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]
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_LIVEINTERVALS_H
#define LLVM_CODEGEN_LIVEINTERVALS_H
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include <iostream>
#include <map>
namespace llvm {
class LiveVariables;
class MRegisterInfo;
class LiveIntervals : public MachineFunctionPass
{
public:
struct Interval {
typedef std::pair<unsigned, unsigned> Range;
typedef std::vector<Range> Ranges;
unsigned reg; // the register of this interval
Ranges ranges; // the ranges this register is valid
Interval(unsigned r)
: reg(r) {
}
unsigned start() const {
assert(!ranges.empty() && "empty interval for register");
return ranges.front().first;
}
unsigned end() const {
assert(!ranges.empty() && "empty interval for register");
return ranges.back().second;
}
bool expired(unsigned index) const {
return end() <= index;
}
bool overlaps(unsigned index) const {
for (Ranges::const_iterator
i = ranges.begin(), e = ranges.end(); i != e; ++i) {
if (index >= i->first && index < i->second) {
return true;
}
}
return false;
}
void addRange(unsigned start, unsigned end) {
Range range = std::make_pair(start, end);
Ranges::iterator it =
std::lower_bound(ranges.begin(), ranges.end(), range);
if (it == ranges.end()) {
it = ranges.insert(it, range);
goto exit;
}
assert(range.first <= it->first && "got wrong iterator?");
// merge ranges if necesary
if (range.first < it->first) {
if (range.second >= it->first) {
it->first = range.first;
}
else {
it = ranges.insert(it, range);
assert(it != ranges.end() && "wtf?");
goto exit;
}
}
exit:
mergeRangesIfNecessary(it);
}
private:
void mergeRangesIfNecessary(Ranges::iterator it) {
while (it != ranges.begin()) {
Ranges::iterator prev = it - 1;
if (prev->second < it->first) {
break;
}
prev->second = it->second;
ranges.erase(it);
it = prev;
}
}
};
struct StartPointComp {
bool operator()(const Interval& lhs, const Interval& rhs) {
return lhs.ranges.front().first < rhs.ranges.front().first;
}
};
struct EndPointComp {
bool operator()(const Interval& lhs, const Interval& rhs) {
return lhs.ranges.back().second < rhs.ranges.back().second;
}
};
typedef std::vector<Interval> Intervals;
typedef std::vector<MachineBasicBlock*> MachineBasicBlockPtrs;
private:
MachineFunction* mf_;
const TargetMachine* tm_;
const MRegisterInfo* mri_;
MachineBasicBlock* currentMbb_;
MachineBasicBlock::iterator currentInstr_;
LiveVariables* lv_;
std::vector<bool> allocatableRegisters_;
typedef std::map<unsigned, MachineBasicBlock*> MbbIndex2MbbMap;
MbbIndex2MbbMap mbbi2mbbMap_;
typedef std::map<MachineInstr*, unsigned> Mi2IndexMap;
Mi2IndexMap mi2iMap_;
typedef std::map<unsigned, unsigned> Reg2IntervalMap;
Reg2IntervalMap r2iMap_;
Intervals intervals_;
public:
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
Intervals& getIntervals() { return intervals_; }
MachineBasicBlockPtrs getOrderedMachineBasicBlockPtrs() const {
MachineBasicBlockPtrs result;
for (MbbIndex2MbbMap::const_iterator
it = mbbi2mbbMap_.begin(), itEnd = mbbi2mbbMap_.end();
it != itEnd; ++it) {
result.push_back(it->second);
}
return result;
}
private:
/// runOnMachineFunction - pass entry point
bool runOnMachineFunction(MachineFunction&);
/// computeIntervals - compute live intervals
void computeIntervals();
/// handleRegisterDef - update intervals for a register def
/// (calls handlePhysicalRegisterDef and
/// handleVirtualRegisterDef)
void handleRegisterDef(MachineBasicBlock* mbb,
MachineBasicBlock::iterator mi,
unsigned reg);
/// handleVirtualRegisterDef - update intervals for a virtual
/// register def
void handleVirtualRegisterDef(MachineBasicBlock* mbb,
MachineBasicBlock::iterator mi,
unsigned reg);
/// handlePhysicalRegisterDef - update intervals for a
/// physical register def
void handlePhysicalRegisterDef(MachineBasicBlock* mbb,
MachineBasicBlock::iterator mi,
unsigned reg);
unsigned getInstructionIndex(MachineInstr* instr) const;
void printRegName(unsigned reg) const;
};
inline bool operator==(const LiveIntervals::Interval& lhs,
const LiveIntervals::Interval& rhs) {
return lhs.reg == rhs.reg;
}
inline std::ostream& operator<<(std::ostream& os,
const LiveIntervals::Interval& li) {
os << "%reg" << li.reg << " = ";
for (LiveIntervals::Interval::Ranges::const_iterator
i = li.ranges.begin(), e = li.ranges.end(); i != e; ++i) {
os << "[" << i->first << ", " << i->second << "]";
}
return os;
}
} // End llvm namespace
#endif
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