llvm-6502/lib/Target/MSP430/MSP430RegisterInfo.cpp
2009-05-03 13:11:20 +00:00

356 lines
12 KiB
C++

//===- MSP430RegisterInfo.cpp - MSP430 Register Information ---------------===//
//
// 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 MSP430 implementation of the TargetRegisterInfo class.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "msp430-reg-info"
#include "MSP430.h"
#include "MSP430MachineFunctionInfo.h"
#include "MSP430RegisterInfo.h"
#include "MSP430TargetMachine.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/ADT/BitVector.h"
using namespace llvm;
// FIXME: Provide proper call frame setup / destroy opcodes.
MSP430RegisterInfo::MSP430RegisterInfo(MSP430TargetMachine &tm,
const TargetInstrInfo &tii)
: MSP430GenRegisterInfo(MSP430::ADJCALLSTACKDOWN, MSP430::ADJCALLSTACKUP),
TM(tm), TII(tii) {
StackAlign = TM.getFrameInfo()->getStackAlignment();
}
const unsigned*
MSP430RegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
static const unsigned CalleeSavedRegs[] = {
MSP430::FPW, MSP430::R5W, MSP430::R6W, MSP430::R7W,
MSP430::R8W, MSP430::R9W, MSP430::R10W, MSP430::R11W,
0
};
return CalleeSavedRegs;
}
const TargetRegisterClass* const*
MSP430RegisterInfo::getCalleeSavedRegClasses(const MachineFunction *MF) const {
static const TargetRegisterClass * const CalleeSavedRegClasses[] = {
&MSP430::GR16RegClass, &MSP430::GR16RegClass,
&MSP430::GR16RegClass, &MSP430::GR16RegClass,
&MSP430::GR16RegClass, &MSP430::GR16RegClass,
&MSP430::GR16RegClass, &MSP430::GR16RegClass,
0
};
return CalleeSavedRegClasses;
}
BitVector
MSP430RegisterInfo::getReservedRegs(const MachineFunction &MF) const {
BitVector Reserved(getNumRegs());
// Mark 4 special registers as reserved.
Reserved.set(MSP430::PCW);
Reserved.set(MSP430::SPW);
Reserved.set(MSP430::SRW);
Reserved.set(MSP430::CGW);
// Mark frame pointer as reserved if needed.
if (hasFP(MF))
Reserved.set(MSP430::FPW);
return Reserved;
}
const TargetRegisterClass* MSP430RegisterInfo::getPointerRegClass() const {
return &MSP430::GR16RegClass;
}
bool MSP430RegisterInfo::hasFP(const MachineFunction &MF) const {
return NoFramePointerElim || MF.getFrameInfo()->hasVarSizedObjects();
}
bool MSP430RegisterInfo::hasReservedCallFrame(MachineFunction &MF) const {
return !MF.getFrameInfo()->hasVarSizedObjects();
}
void MSP430RegisterInfo::
eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
if (!hasReservedCallFrame(MF)) {
// If the stack pointer can be changed after prologue, turn the
// adjcallstackup instruction into a 'sub SPW, <amt>' and the
// adjcallstackdown instruction into 'add SPW, <amt>'
// TODO: consider using push / pop instead of sub + store / add
MachineInstr *Old = I;
uint64_t Amount = Old->getOperand(0).getImm();
if (Amount != 0) {
// We need to keep the stack aligned properly. To do this, we round the
// amount of space needed for the outgoing arguments up to the next
// alignment boundary.
Amount = (Amount+StackAlign-1)/StackAlign*StackAlign;
MachineInstr *New = 0;
if (Old->getOpcode() == getCallFrameSetupOpcode()) {
New = BuildMI(MF, Old->getDebugLoc(),
TII.get(MSP430::SUB16ri), MSP430::SPW)
.addReg(MSP430::SPW).addImm(Amount);
} else {
assert(Old->getOpcode() == getCallFrameDestroyOpcode());
// factor out the amount the callee already popped.
uint64_t CalleeAmt = Old->getOperand(1).getImm();
Amount -= CalleeAmt;
if (Amount)
New = BuildMI(MF, Old->getDebugLoc(),
TII.get(MSP430::ADD16ri), MSP430::SPW)
.addReg(MSP430::SPW).addImm(Amount);
}
if (New) {
// The SRW implicit def is dead.
New->getOperand(3).setIsDead();
// Replace the pseudo instruction with a new instruction...
MBB.insert(I, New);
}
}
} else if (I->getOpcode() == getCallFrameDestroyOpcode()) {
// If we are performing frame pointer elimination and if the callee pops
// something off the stack pointer, add it back.
if (uint64_t CalleeAmt = I->getOperand(1).getImm()) {
MachineInstr *Old = I;
MachineInstr *New =
BuildMI(MF, Old->getDebugLoc(), TII.get(MSP430::SUB16ri),
MSP430::SPW).addReg(MSP430::SPW).addImm(CalleeAmt);
// The SRW implicit def is dead.
New->getOperand(3).setIsDead();
MBB.insert(I, New);
}
}
MBB.erase(I);
}
void
MSP430RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
int SPAdj, RegScavenger *RS) const {
assert(SPAdj == 0 && "Unexpected");
unsigned i = 0;
MachineInstr &MI = *II;
MachineBasicBlock &MBB = *MI.getParent();
MachineFunction &MF = *MBB.getParent();
DebugLoc dl = MI.getDebugLoc();
while (!MI.getOperand(i).isFI()) {
++i;
assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
}
int FrameIndex = MI.getOperand(i).getIndex();
unsigned BasePtr = (hasFP(MF) ? MSP430::FPW : MSP430::SPW);
int Offset = MF.getFrameInfo()->getObjectOffset(FrameIndex);
// Skip the saved PC
Offset += 2;
if (!hasFP(MF))
Offset += MF.getFrameInfo()->getStackSize();
else
Offset += 2; // Skip the saved FPW
// Fold imm into offset
Offset += MI.getOperand(i+1).getImm();
if (MI.getOpcode() == MSP430::ADD16ri) {
// This is actually "load effective address" of the stack slot
// instruction. We have only two-address instructions, thus we need to
// expand it into mov + add
MI.setDesc(TII.get(MSP430::MOV16rr));
MI.getOperand(i).ChangeToRegister(BasePtr, false);
if (Offset == 0)
return;
// We need to materialize the offset via add instruction.
unsigned DstReg = MI.getOperand(0).getReg();
if (Offset < 0)
BuildMI(MBB, next(II), dl, TII.get(MSP430::SUB16ri), DstReg)
.addReg(DstReg).addImm(-Offset);
else
BuildMI(MBB, next(II), dl, TII.get(MSP430::ADD16ri), DstReg)
.addReg(DstReg).addImm(Offset);
return;
}
MI.getOperand(i).ChangeToRegister(BasePtr, false);
MI.getOperand(i+1).ChangeToImmediate(Offset);
}
void
MSP430RegisterInfo::processFunctionBeforeFrameFinalized(MachineFunction &MF)
const {
// Create a frame entry for the FPW register that must be saved.
if (hasFP(MF)) {
int FrameIdx = MF.getFrameInfo()->CreateFixedObject(2, -4);
assert(FrameIdx == MF.getFrameInfo()->getObjectIndexBegin() &&
"Slot for FPW register must be last in order to be found!");
FrameIdx = 0;
}
}
void MSP430RegisterInfo::emitPrologue(MachineFunction &MF) const {
MachineBasicBlock &MBB = MF.front(); // Prolog goes in entry BB
MachineFrameInfo *MFI = MF.getFrameInfo();
MSP430MachineFunctionInfo *MSP430FI = MF.getInfo<MSP430MachineFunctionInfo>();
MachineBasicBlock::iterator MBBI = MBB.begin();
DebugLoc DL = (MBBI != MBB.end() ? MBBI->getDebugLoc() :
DebugLoc::getUnknownLoc());
// Get the number of bytes to allocate from the FrameInfo.
uint64_t StackSize = MFI->getStackSize();
uint64_t NumBytes = 0;
if (hasFP(MF)) {
// Calculate required stack adjustment
uint64_t FrameSize = StackSize - 2;
NumBytes = FrameSize - MSP430FI->getCalleeSavedFrameSize();
// Get the offset of the stack slot for the EBP register... which is
// guaranteed to be the last slot by processFunctionBeforeFrameFinalized.
// Update the frame offset adjustment.
MFI->setOffsetAdjustment(-NumBytes);
// Save FPW into the appropriate stack slot...
BuildMI(MBB, MBBI, DL, TII.get(MSP430::PUSH16r))
.addReg(MSP430::FPW, /*isDef=*/false, /*isImp=*/false, /*isKill=*/true);
// Update FPW with the new base value...
BuildMI(MBB, MBBI, DL, TII.get(MSP430::MOV16rr), MSP430::FPW)
.addReg(MSP430::SPW);
// Mark the FramePtr as live-in in every block except the entry.
for (MachineFunction::iterator I = next(MF.begin()), E = MF.end();
I != E; ++I)
I->addLiveIn(MSP430::FPW);
} else
NumBytes = StackSize - MSP430FI->getCalleeSavedFrameSize();
// Skip the callee-saved push instructions.
while (MBBI != MBB.end() && (MBBI->getOpcode() == MSP430::PUSH16r))
++MBBI;
if (MBBI != MBB.end())
DL = MBBI->getDebugLoc();
if (NumBytes) { // adjust stack pointer: SPW -= numbytes
// If there is an SUB16ri of SPW immediately before this instruction, merge
// the two.
//NumBytes -= mergeSPUpdates(MBB, MBBI, true);
// If there is an ADD16ri or SUB16ri of SPW immediately after this
// instruction, merge the two instructions.
// mergeSPUpdatesDown(MBB, MBBI, &NumBytes);
if (NumBytes) {
MachineInstr *MI =
BuildMI(MBB, MBBI, DL, TII.get(MSP430::SUB16ri), MSP430::SPW)
.addReg(MSP430::SPW).addImm(NumBytes);
// The SRW implicit def is dead.
MI->getOperand(3).setIsDead();
}
}
}
void MSP430RegisterInfo::emitEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
MSP430MachineFunctionInfo *MSP430FI = MF.getInfo<MSP430MachineFunctionInfo>();
MachineBasicBlock::iterator MBBI = prior(MBB.end());
unsigned RetOpcode = MBBI->getOpcode();
DebugLoc DL = MBBI->getDebugLoc();
switch (RetOpcode) {
case MSP430::RET: break; // These are ok
default:
assert(0 && "Can only insert epilog into returning blocks");
}
// Get the number of bytes to allocate from the FrameInfo
uint64_t StackSize = MFI->getStackSize();
unsigned CSSize = MSP430FI->getCalleeSavedFrameSize();
uint64_t NumBytes = 0;
if (hasFP(MF)) {
// Calculate required stack adjustment
uint64_t FrameSize = StackSize - 2;
NumBytes = FrameSize - CSSize;
// pop FPW.
BuildMI(MBB, MBBI, DL, TII.get(MSP430::POP16r), MSP430::FPW);
} else
NumBytes = StackSize - CSSize;
// Skip the callee-saved pop instructions.
MachineBasicBlock::iterator LastCSPop = MBBI;
while (MBBI != MBB.begin()) {
MachineBasicBlock::iterator PI = prior(MBBI);
unsigned Opc = PI->getOpcode();
if (Opc != MSP430::POP16r && !PI->getDesc().isTerminator())
break;
--MBBI;
}
DL = MBBI->getDebugLoc();
// If there is an ADD16ri or SUB16ri of SPW immediately before this
// instruction, merge the two instructions.
//if (NumBytes || MFI->hasVarSizedObjects())
// mergeSPUpdatesUp(MBB, MBBI, StackPtr, &NumBytes);
if (MFI->hasVarSizedObjects()) {
assert(0 && "Not implemented yet!");
} else {
// adjust stack pointer back: SPW += numbytes
if (NumBytes) {
MachineInstr *MI =
BuildMI(MBB, MBBI, DL, TII.get(MSP430::ADD16ri), MSP430::SPW)
.addReg(MSP430::SPW).addImm(NumBytes);
// The SRW implicit def is dead.
MI->getOperand(3).setIsDead();
}
}
}
unsigned MSP430RegisterInfo::getRARegister() const {
return MSP430::PCW;
}
unsigned MSP430RegisterInfo::getFrameRegister(MachineFunction &MF) const {
return hasFP(MF) ? MSP430::FPW : MSP430::SPW;
}
int MSP430RegisterInfo::getDwarfRegNum(unsigned RegNum, bool isEH) const {
assert(0 && "Not implemented yet!");
}
#include "MSP430GenRegisterInfo.inc"