#ifndef LLVM_CODEGEN_REGISTER_SCAVENGING_H
#define LLVM_CODEGEN_REGISTER_SCAVENGING_H
-#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/ADT/BitVector.h"
+#include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
namespace llvm {
class TargetRegisterClass;
class RegScavenger {
+ const TargetRegisterInfo *TRI;
+ const TargetInstrInfo *TII;
+ MachineRegisterInfo* MRI;
MachineBasicBlock *MBB;
MachineBasicBlock::iterator MBBI;
unsigned NumPhysRegs;
///
const TargetRegisterClass *ScavengedRC;
+ /// ScavengeRestore - Instruction that restores the scavenged register from
+ /// stack.
+ const MachineInstr *ScavengeRestore;
+
+ /// CalleeSavedrRegs - A bitvector of callee saved registers for the target.
+ ///
+ BitVector CalleeSavedRegs;
+
/// RegsAvailable - The current state of all the physical registers immediately
/// before MBBI. One bit per physical register. If bit is set that means it's
/// available, unset means the register is currently being used.
BitVector RegsAvailable;
- /// ImplicitDefed - If bit is set that means the register is defined by an
- /// implicit_def instructions. That means it can be clobbered at will.
- BitVector ImplicitDefed;
+ // These BitVectors are only used internally to forward(). They are members
+ // to avoid frequent reallocations.
+ BitVector KillRegs, DefRegs;
public:
RegScavenger()
: MBB(NULL), NumPhysRegs(0), Tracking(false),
ScavengingFrameIndex(-1), ScavengedReg(0), ScavengedRC(NULL) {}
- explicit RegScavenger(MachineBasicBlock *mbb)
- : MBB(mbb), NumPhysRegs(0), Tracking(false),
- ScavengingFrameIndex(-1), ScavengedReg(0), ScavengedRC(NULL) {}
-
/// enterBasicBlock - Start tracking liveness from the begin of the specific
/// basic block.
void enterBasicBlock(MachineBasicBlock *mbb);
- /// forward / backward - Move the internal MBB iterator and update register
- /// states.
+ /// initRegState - allow resetting register state info for multiple
+ /// passes over/within the same function.
+ void initRegState();
+
+ /// forward - Move the internal MBB iterator and update register states.
void forward();
- void backward();
- /// forward / backward - Move the internal MBB iterator and update register
- /// states until it has processed the specific iterator.
+ /// forward - Move the internal MBB iterator and update register states until
+ /// it has processed the specific iterator.
void forward(MachineBasicBlock::iterator I) {
+ if (!Tracking && MBB->begin() != I) forward();
while (MBBI != I) forward();
}
- void backward(MachineBasicBlock::iterator I) {
- while (MBBI != I) backward();
- }
/// skipTo - Move the internal MBB iterator but do not update register states.
///
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]; }
-
- bool isImplicitlyDefined(unsigned Reg) const { return ImplicitDefed[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, bool ImpDef = false);
- void setUsed(BitVector Regs, bool ImpDef = false) {
- RegsAvailable &= ~Regs;
- if (ImpDef)
- ImplicitDefed |= Regs;
- else
- ImplicitDefed &= ~Regs;
- }
- void setUnused(unsigned Reg, const MachineInstr *MI);
- void setUnused(BitVector Regs) {
- RegsAvailable |= Regs;
- ImplicitDefed &= ~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:
- const TargetRegisterInfo *TRI;
- const TargetInstrInfo *TII;
- MachineRegisterInfo* MRI;
+ /// isReserved - Returns true if a register is reserved. It is never "unused".
+ bool isReserved(unsigned Reg) const { return MRI->isReserved(Reg); }
- /// CalleeSavedrRegs - A bitvector of callee saved registers for the target.
+ /// isUsed - Test if a register is currently being used. When called by the
+ /// isAliasUsed function, we only check isReserved if this is the original
+ /// register, not an alias register.
///
- BitVector CalleeSavedRegs;
+ bool isUsed(unsigned Reg, bool CheckReserved = true) const {
+ return !RegsAvailable.test(Reg) || (CheckReserved && isReserved(Reg));
+ }
+
+ /// 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;
+ }
- /// ReservedRegs - A bitvector of reserved registers.
+ /// Add Reg and all its sub-registers to BV.
+ void addRegWithSubRegs(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.
///
- BitVector ReservedRegs;
+ /// No more than InstrLimit instructions are inspected.
+ unsigned findSurvivorReg(MachineBasicBlock::iterator StartMI,
+ BitVector &Candidates,
+ unsigned InstrLimit,
+ MachineBasicBlock::iterator &UseMI);
- /// restoreScavengedReg - Restore scavenged by loading it back from the
- /// emergency spill slot. Mark it used.
- void restoreScavengedReg();
};
-
+
} // End llvm namespace
#endif
projects / oota-llvm.git / blobdiff