llvm-6502/lib/Target/PowerPC/PPCRegisterInfo.h
Jim Grosbach b58f498f75 Add register-reuse to frame-index register scavenging. When a target uses
a virtual register to eliminate a frame index, it can return that register
and the constant stored there to PEI to track. When scavenging to allocate
for those registers, PEI then tracks the last-used register and value, and
if it is still available and matches the value for the next index, reuses
the existing value rather and removes the re-materialization instructions.
Fancier tracking and adjustment of scavenger allocations to keep more
values live for longer is possible, but not yet implemented and would likely
be better done via a different, less special-purpose, approach to the
problem.

eliminateFrameIndex() is modified so the target implementations can return
the registers they wish to be tracked for reuse.

ARM Thumb1 implements and utilizes the new mechanism. All other targets are
simply modified to adjust for the changed eliminateFrameIndex() prototype.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83467 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-07 17:12:56 +00:00

99 lines
3.5 KiB
C++

//===- PPCRegisterInfo.h - PowerPC Register Information Impl -----*- C++ -*-==//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the PowerPC implementation of the TargetRegisterInfo
// class.
//
//===----------------------------------------------------------------------===//
#ifndef POWERPC32_REGISTERINFO_H
#define POWERPC32_REGISTERINFO_H
#include "PPC.h"
#include "PPCGenRegisterInfo.h.inc"
#include <map>
namespace llvm {
class PPCSubtarget;
class TargetInstrInfo;
class Type;
class PPCRegisterInfo : public PPCGenRegisterInfo {
std::map<unsigned, unsigned> ImmToIdxMap;
const PPCSubtarget &Subtarget;
const TargetInstrInfo &TII;
public:
PPCRegisterInfo(const PPCSubtarget &SubTarget, const TargetInstrInfo &tii);
/// getRegisterNumbering - Given the enum value for some register, e.g.
/// PPC::F14, return the number that it corresponds to (e.g. 14).
static unsigned getRegisterNumbering(unsigned RegEnum);
/// getPointerRegClass - Return the register class to use to hold pointers.
/// This is used for addressing modes.
virtual const TargetRegisterClass *getPointerRegClass(unsigned Kind=0) const;
/// Code Generation virtual methods...
const unsigned *getCalleeSavedRegs(const MachineFunction* MF = 0) const;
const TargetRegisterClass* const*
getCalleeSavedRegClasses(const MachineFunction *MF = 0) const;
BitVector getReservedRegs(const MachineFunction &MF) const;
/// targetHandlesStackFrameRounding - Returns true if the target is
/// responsible for rounding up the stack frame (probably at emitPrologue
/// time).
bool targetHandlesStackFrameRounding() const { return true; }
/// requiresRegisterScavenging - We require a register scavenger.
/// FIXME (64-bit): Should be inlined.
bool requiresRegisterScavenging(const MachineFunction &MF) const;
bool hasFP(const MachineFunction &MF) const;
void eliminateCallFramePseudoInstr(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const;
void lowerDynamicAlloc(MachineBasicBlock::iterator II,
int SPAdj, RegScavenger *RS) const;
void lowerCRSpilling(MachineBasicBlock::iterator II, unsigned FrameIndex,
int SPAdj, RegScavenger *RS) const;
unsigned eliminateFrameIndex(MachineBasicBlock::iterator II,
int SPAdj, int *Value = NULL,
RegScavenger *RS = NULL) const;
/// determineFrameLayout - Determine the size of the frame and maximum call
/// frame size.
void determineFrameLayout(MachineFunction &MF) const;
void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
RegScavenger *RS = NULL) const;
void processFunctionBeforeFrameFinalized(MachineFunction &MF) const;
void emitPrologue(MachineFunction &MF) const;
void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const;
// Debug information queries.
unsigned getRARegister() const;
unsigned getFrameRegister(MachineFunction &MF) const;
void getInitialFrameState(std::vector<MachineMove> &Moves) const;
// Exception handling queries.
unsigned getEHExceptionRegister() const;
unsigned getEHHandlerRegister() const;
int getDwarfRegNum(unsigned RegNum, bool isEH) const;
};
} // end namespace llvm
#endif