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//===-- LiveRangeInfo.h - Track all LiveRanges for a Function ----*- 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 contains the class LiveRangeInfo which constructs and keeps
// the LiveRangeMap which contains all the live ranges used in a method.
//
// Assumptions:
//
// All variables (llvm Values) are defined before they are used. However, a
// constant may not be defined in the machine instruction stream if it can be
// used as an immediate value within a machine instruction. However, register
// allocation does not have to worry about immediate constants since they
// do not require registers.
//
// Since an llvm Value has a list of uses associated, it is sufficient to
// record only the defs in a Live Range.
//
//===----------------------------------------------------------------------===//
#ifndef LIVERANGEINFO_H
#define LIVERANGEINFO_H
#include "llvm/CodeGen/ValueSet.h"
#include "Support/hash_map"
class LiveRange;
class MachineInstr;
class RegClass;
class TargetRegInfo;
class TargetMachine;
class Value;
class Function;
class Instruction;
typedef hash_map<const Value*, LiveRange*> LiveRangeMapType;
//----------------------------------------------------------------------------
// Class LiveRangeInfo
//
// Constructs and keeps the LiveRangeMap which contains all the live
// ranges used in a method. Also contain methods to coalesce live ranges.
//----------------------------------------------------------------------------
class LiveRangeInfo {
const Function *const Meth; // Func for which live range info is held
LiveRangeMapType LiveRangeMap; // A map from Value * to LiveRange * to
// record all live ranges in a method
// created by constructLiveRanges
const TargetMachine& TM; // target machine description
std::vector<RegClass *> & RegClassList;// vector containing register classess
const TargetRegInfo& MRI; // machine reg info
std::vector<MachineInstr*> CallRetInstrList; // a list of all call/ret instrs
//------------ Private methods (see LiveRangeInfo.cpp for description)-------
LiveRange* createNewLiveRange (const Value* Def,
bool isCC = false);
LiveRange* createOrAddToLiveRange (const Value* Def,
bool isCC = false);
void unionAndUpdateLRs (LiveRange *L1,
LiveRange *L2);
void addInterference (const Instruction *Inst,
const ValueSet *LVSet);
void suggestRegs4CallRets ();
const Function *getMethod () const { return Meth; }
public:
LiveRangeInfo(const Function *F,
const TargetMachine& tm,
std::vector<RegClass *> & RCList);
/// Destructor to destroy all LiveRanges in the LiveRange Map
///
~LiveRangeInfo();
// Main entry point for live range construction
//
void constructLiveRanges();
/// return the common live range map for this method
///
inline const LiveRangeMapType *getLiveRangeMap() const
{ return &LiveRangeMap; }
/// Method used to get the live range containing a Value.
/// This may return NULL if no live range exists for a Value (eg, some consts)
///
inline LiveRange *getLiveRangeForValue(const Value *Val) {
return LiveRangeMap[Val];
}
inline const LiveRange *getLiveRangeForValue(const Value *Val) const {
LiveRangeMapType::const_iterator I = LiveRangeMap.find(Val);
return I->second;
}
/// Method for coalescing live ranges. Called only after interference info
/// is calculated.
///
void coalesceLRs();
/// debugging method to print the live ranges
///
void printLiveRanges();
};
#endif
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