#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/ADT/BitVector.h"
-#include "llvm/ADT/DenseMap.h"
namespace llvm {
/// available, unset means the register is currently being used.
BitVector RegsAvailable;
- /// CurrDist - Distance from MBB entry to the current instruction MBBI.
- ///
- unsigned CurrDist;
-
- /// DistanceMap - Keep track the distance of a MI from the start of the
- /// current basic block.
- DenseMap<MachineInstr*, unsigned> DistanceMap;
+ // These BitVectors are only used internally to forward(). They are members
+ // to avoid frequent reallocations.
+ BitVector KillRegs, DefRegs;
public:
RegScavenger()
///
void skipTo(MachineBasicBlock::iterator I) { MBBI = I; }
- /// isReserved - Returns true if a register is reserved. It is never "unused".
- bool isReserved(unsigned Reg) const { return ReservedRegs[Reg]; }
-
- /// isUsed / isUsed - Test if a register is currently being used.
- ///
- bool isUsed(unsigned Reg) const { return !RegsAvailable[Reg]; }
- bool isUnused(unsigned Reg) const { return RegsAvailable[Reg]; }
-
/// getRegsUsed - return all registers currently in use in used.
void getRegsUsed(BitVector &used, bool includeReserved);
- /// setUsed / setUnused - Mark the state of one or a number of registers.
- ///
- void setUsed(unsigned Reg);
- void setUsed(BitVector &Regs) {
- RegsAvailable &= ~Regs;
- }
- void setUnused(unsigned Reg, const MachineInstr *MI);
- void setUnused(BitVector &Regs) {
- RegsAvailable |= Regs;
- }
-
- /// FindUnusedReg - Find a unused register of the specified register class
- /// from the specified set of registers. It return 0 is none is found.
- unsigned FindUnusedReg(const TargetRegisterClass *RegClass,
- const BitVector &Candidates) const;
+ /// getRegsAvailable - Return all available registers in the register class
+ /// in Mask.
+ BitVector getRegsAvailable(const TargetRegisterClass *RC);
/// FindUnusedReg - Find a unused register of the specified register class.
- /// Exclude callee saved registers if directed. It return 0 is none is found.
- unsigned FindUnusedReg(const TargetRegisterClass *RegClass,
- bool ExCalleeSaved = false) const;
+ /// Return 0 if none is found.
+ unsigned FindUnusedReg(const TargetRegisterClass *RegClass) const;
/// setScavengingFrameIndex / getScavengingFrameIndex - accessor and setter of
/// ScavengingFrameIndex.
return scavengeRegister(RegClass, MBBI, SPAdj);
}
+ /// setUsed - Tell the scavenger a register is used.
+ ///
+ void setUsed(unsigned Reg);
private:
- /// restoreScavengedReg - Restore scavenged by loading it back from the
- /// emergency spill slot. Mark it used.
- void restoreScavengedReg();
+ /// isReserved - Returns true if a register is reserved. It is never "unused".
+ bool isReserved(unsigned Reg) const { return ReservedRegs.test(Reg); }
+
+ /// isUsed / isUnused - Test if a register is currently being used.
+ ///
+ bool isUsed(unsigned Reg) const {
+ return !RegsAvailable.test(Reg) || ReservedRegs.test(Reg);
+ }
- MachineInstr *findFirstUse(MachineBasicBlock *MBB,
- MachineBasicBlock::iterator I, unsigned Reg,
- unsigned &Dist);
+ /// isAliasUsed - Is Reg or an alias currently in use?
+ bool isAliasUsed(unsigned Reg) const;
+
+ /// setUsed / setUnused - Mark the state of one or a number of registers.
+ ///
+ void setUsed(BitVector &Regs) {
+ RegsAvailable.reset(Regs);
+ }
+ void setUnused(BitVector &Regs) {
+ RegsAvailable |= Regs;
+ }
/// Add Reg and all its sub-registers to BV.
void addRegWithSubRegs(BitVector &BV, unsigned Reg);
- /// Add Reg and its aliases to BV.
- void addRegWithAliases(BitVector &BV, unsigned Reg);
+ /// findSurvivorReg - Return the candidate register that is unused for the
+ /// longest after StartMI. UseMI is set to the instruction where the search
+ /// stopped.
+ ///
+ /// No more than InstrLimit instructions are inspected.
+ unsigned findSurvivorReg(MachineBasicBlock::iterator StartMI,
+ BitVector &Candidates,
+ unsigned InstrLimit,
+ MachineBasicBlock::iterator &UseMI);
+
};
} // End llvm namespace