llvm-6502/lib/Target/XCore/XCoreRegisterInfo.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

96 lines
3.2 KiB
C++

//===- XCoreRegisterInfo.h - XCore 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 XCore implementation of the MRegisterInfo class.
//
//===----------------------------------------------------------------------===//
#ifndef XCOREREGISTERINFO_H
#define XCOREREGISTERINFO_H
#include "llvm/Target/TargetRegisterInfo.h"
#include "XCoreGenRegisterInfo.h.inc"
namespace llvm {
class TargetInstrInfo;
struct XCoreRegisterInfo : public XCoreGenRegisterInfo {
private:
const TargetInstrInfo &TII;
void loadConstant(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
unsigned DstReg, int64_t Value, DebugLoc dl) const;
void storeToStack(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
unsigned SrcReg, int Offset, DebugLoc dl) const;
void loadFromStack(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
unsigned DstReg, int Offset, DebugLoc dl) const;
public:
XCoreRegisterInfo(const TargetInstrInfo &tii);
/// 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;
bool requiresRegisterScavenging(const MachineFunction &MF) const;
bool hasFP(const MachineFunction &MF) const;
void eliminateCallFramePseudoInstr(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const;
unsigned eliminateFrameIndex(MachineBasicBlock::iterator II,
int SPAdj, int *Value = NULL,
RegScavenger *RS = NULL) 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;
//! Return the array of argument passing registers
/*!
\note The size of this array is returned by getArgRegsSize().
*/
static const unsigned *getArgRegs(const MachineFunction *MF = 0);
//! Return the size of the argument passing register array
static unsigned getNumArgRegs(const MachineFunction *MF = 0);
//! Return whether to emit frame moves
static bool needsFrameMoves(const MachineFunction &MF);
//! Get DWARF debugging register number
int getDwarfRegNum(unsigned RegNum, bool isEH) const;
};
} // end namespace llvm
#endif