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llvm-6502/lib/Target/XCore/XCoreRegisterInfo.cpp
Richard Osborne b25baef26f Add XCore backend. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58838 91177308-0d34-0410-b5e6-96231b3b80d8
2008-11-07 10:59:00 +00:00

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//===- XCoreRegisterInfo.cpp - XCore Register Information -------*- 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.
//
//===----------------------------------------------------------------------===//
#include "XCoreRegisterInfo.h"
#include "XCoreMachineFunctionInfo.h"
#include "XCore.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineLocation.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RegisterScavenging.h"
#include "llvm/Target/TargetFrameInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Type.h"
#include "llvm/Function.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/Debug.h"
using namespace llvm;
XCoreRegisterInfo::XCoreRegisterInfo(const TargetInstrInfo &tii)
: XCoreGenRegisterInfo(XCore::ADJCALLSTACKDOWN, XCore::ADJCALLSTACKUP),
TII(tii) {
}
// helper functions
static inline bool isImmUs(unsigned val) {
return val <= 11;
}
static inline bool isImmU6(unsigned val) {
return val < (1 << 6);
}
static inline bool isImmU16(unsigned val) {
return val < (1 << 16);
}
static const unsigned XCore_ArgRegs[] = {
XCore::R0, XCore::R1, XCore::R2, XCore::R3
};
const unsigned * XCoreRegisterInfo::getArgRegs(const MachineFunction *MF)
{
return XCore_ArgRegs;
}
unsigned XCoreRegisterInfo::getNumArgRegs(const MachineFunction *MF)
{
return array_lengthof(XCore_ArgRegs);
}
bool XCoreRegisterInfo::needsFrameMoves(const MachineFunction &MF)
{
const MachineFrameInfo *MFI = MF.getFrameInfo();
MachineModuleInfo *MMI = MFI->getMachineModuleInfo();
return (MMI && MMI->hasDebugInfo()) ||
!MF.getFunction()->doesNotThrow() ||
UnwindTablesMandatory;
}
const unsigned* XCoreRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF)
const {
static const unsigned CalleeSavedRegs[] = {
XCore::R4, XCore::R5, XCore::R6, XCore::R7,
XCore::R8, XCore::R9, XCore::R10, XCore::LR,
0
};
return CalleeSavedRegs;
}
const TargetRegisterClass* const*
XCoreRegisterInfo::getCalleeSavedRegClasses(const MachineFunction *MF) const {
static const TargetRegisterClass * const CalleeSavedRegClasses[] = {
XCore::GRRegsRegisterClass, XCore::GRRegsRegisterClass,
XCore::GRRegsRegisterClass, XCore::GRRegsRegisterClass,
XCore::GRRegsRegisterClass, XCore::GRRegsRegisterClass,
XCore::GRRegsRegisterClass, XCore::RRegsRegisterClass,
0
};
return CalleeSavedRegClasses;
}
BitVector XCoreRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
BitVector Reserved(getNumRegs());
Reserved.set(XCore::CP);
Reserved.set(XCore::DP);
Reserved.set(XCore::SP);
Reserved.set(XCore::LR);
if (hasFP(MF)) {
Reserved.set(XCore::R10);
}
return Reserved;
}
bool
XCoreRegisterInfo::requiresRegisterScavenging(const MachineFunction &MF) const {
// TODO can we estimate stack size?
return hasFP(MF);
}
bool XCoreRegisterInfo::hasFP(const MachineFunction &MF) const {
return NoFramePointerElim || MF.getFrameInfo()->hasVarSizedObjects();
}
// This function eliminates ADJCALLSTACKDOWN,
// ADJCALLSTACKUP pseudo instructions
void XCoreRegisterInfo::
eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
if (!hasReservedCallFrame(MF)) {
// Turn the adjcallstackdown instruction into 'extsp <amt>' and the
// adjcallstackup instruction into 'ldaw sp, sp[<amt>]'
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.
unsigned Align = MF.getTarget().getFrameInfo()->getStackAlignment();
Amount = (Amount+Align-1)/Align*Align;
assert(Amount%4 == 0);
Amount /= 4;
bool isU6 = isImmU6(Amount);
if (!isU6 && !isImmU16(Amount)) {
// FIX could emit multiple instructions in this case.
cerr << "eliminateCallFramePseudoInstr size too big: "
<< Amount << "\n";
abort();
}
MachineInstr *New;
if (Old->getOpcode() == XCore::ADJCALLSTACKDOWN) {
int Opcode = isU6 ? XCore::EXTSP_u6 : XCore::EXTSP_lu6;
New=BuildMI(MF, TII.get(Opcode))
.addImm(Amount);
} else {
assert(Old->getOpcode() == XCore::ADJCALLSTACKUP);
int Opcode = isU6 ? XCore::LDAWSP_ru6_RRegs : XCore::LDAWSP_lru6_RRegs;
New=BuildMI(MF, TII.get(Opcode), XCore::SP)
.addImm(Amount);
}
// Replace the pseudo instruction with a new instruction...
MBB.insert(I, New);
}
}
MBB.erase(I);
}
void XCoreRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
int SPAdj, RegScavenger *RS) const {
assert(SPAdj == 0 && "Unexpected");
MachineInstr &MI = *II;
unsigned i = 0;
while (!MI.getOperand(i).isFI()) {
++i;
assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
}
MachineOperand &FrameOp = MI.getOperand(i);
int FrameIndex = FrameOp.getIndex();
MachineFunction &MF = *MI.getParent()->getParent();
int Offset = MF.getFrameInfo()->getObjectOffset(FrameIndex);
int StackSize = MF.getFrameInfo()->getStackSize();
#ifndef NDEBUG
DOUT << "\nFunction : " << MF.getFunction()->getName() << "\n";
DOUT << "<--------->\n";
MI.print(DOUT);
DOUT << "FrameIndex : " << FrameIndex << "\n";
DOUT << "FrameOffset : " << Offset << "\n";
DOUT << "StackSize : " << StackSize << "\n";
#endif
Offset += StackSize;
// fold constant into offset.
Offset += MI.getOperand(i + 1).getImm();
MI.getOperand(i + 1).ChangeToImmediate(0);
assert(Offset%4 == 0 && "Misaligned stack offset");
#ifndef NDEBUG
DOUT << "Offset : " << Offset << "\n";
DOUT << "<--------->\n";
#endif
Offset/=4;
bool FP = hasFP(MF);
if (FP) {
bool isUs = isImmUs(Offset);
MachineBasicBlock &MBB = *MI.getParent();
unsigned FramePtr = XCore::R10;
unsigned Reg = MI.getOperand(0).getReg();
bool isKill = MI.getOperand(0).isKill();
if (Reg == XCore::LR) {
// The LR should have been save in the prologue.
cerr << "saving LR to FP unimplemented\n";
abort();
}
MachineInstr *New = 0;
if (!isUs) {
if (!RS) {
cerr << "eliminateFrameIndex Frame size too big: " << Offset << "\n";
abort();
}
unsigned ScratchReg = RS->scavengeRegister(XCore::GRRegsRegisterClass, II,
SPAdj);
loadConstant(MBB, II, ScratchReg, Offset);
switch (MI.getOpcode()) {
case XCore::LDWSP_lru6:
New = BuildMI(MBB, II, TII.get(XCore::LDW_3r), Reg)
.addReg(FramePtr)
.addReg(ScratchReg, false, false, true);
break;
case XCore::STWSP_lru6:
New = BuildMI(MBB, II, TII.get(XCore::STW_3r))
.addReg(Reg, false, false, isKill)
.addReg(FramePtr)
.addReg(ScratchReg, false, false, true);
break;
case XCore::LDAWSP_lru6:
New = BuildMI(MBB, II, TII.get(XCore::LDAWF_l3r), Reg)
.addReg(FramePtr)
.addReg(ScratchReg, false, false, true);
break;
default:
assert(0 && "Unexpected Opcode\n");
}
} else {
switch (MI.getOpcode()) {
case XCore::LDWSP_lru6:
New = BuildMI(MBB, II, TII.get(XCore::LDW_2rus), Reg)
.addReg(FramePtr)
.addImm(Offset);
break;
case XCore::STWSP_lru6:
New = BuildMI(MBB, II, TII.get(XCore::STW_2rus))
.addReg(Reg, false, false, isKill)
.addReg(FramePtr)
.addImm(Offset);
break;
case XCore::LDAWSP_lru6:
New = BuildMI(MBB, II, TII.get(XCore::LDAWF_l2rus), Reg)
.addReg(FramePtr)
.addImm(Offset);
break;
default:
assert(0 && "Unexpected Opcode\n");
}
}
// Erase old instruction.
MBB.erase(II);
} else {
bool isU6 = isImmU6(Offset);
if (!isU6 && !isImmU16(Offset)) {
// FIXME could make this work for LDWSP, LDAWSP.
cerr << "eliminateFrameIndex Frame size too big: " << Offset << "\n";
abort();
}
int NewOpcode = MI.getOpcode();
switch (NewOpcode) {
case XCore::LDWSP_lru6:
NewOpcode = (isU6) ? XCore::LDWSP_ru6 : XCore::LDWSP_lru6;
break;
case XCore::STWSP_lru6:
NewOpcode = (isU6) ? XCore::STWSP_ru6 : XCore::STWSP_lru6;
break;
case XCore::LDAWSP_lru6:
NewOpcode = (isU6) ? XCore::LDAWSP_ru6 : XCore::LDAWSP_lru6;
break;
default:
assert(0 && "Unexpected Opcode\n");
}
MI.setDesc(TII.get(NewOpcode));
FrameOp.ChangeToImmediate(Offset);
}
}
void
XCoreRegisterInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
RegScavenger *RS) const {
MachineFrameInfo *MFI = MF.getFrameInfo();
bool LRUsed = MF.getRegInfo().isPhysRegUsed(XCore::LR);
const TargetRegisterClass *RC = XCore::GRRegsRegisterClass;
XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
if (LRUsed) {
MF.getRegInfo().setPhysRegUnused(XCore::LR);
bool isVarArg = MF.getFunction()->isVarArg();
int FrameIdx;
if (! isVarArg) {
// A fixed offset of 0 allows us to save / restore LR using entsp / retsp.
FrameIdx = MFI->CreateFixedObject(RC->getSize(), 0);
} else {
FrameIdx = MFI->CreateStackObject(RC->getSize(), RC->getAlignment());
}
XFI->setUsesLR(FrameIdx);
XFI->setLRSpillSlot(FrameIdx);
}
if (requiresRegisterScavenging(MF)) {
// Reserve a slot close to SP or frame pointer.
RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
RC->getAlignment()));
}
if (hasFP(MF)) {
// A callee save register is used to hold the FP.
// This needs saving / restoring in the epilogue / prologue.
XFI->setFPSpillSlot(MFI->CreateStackObject(RC->getSize(),
RC->getAlignment()));
}
}
void XCoreRegisterInfo::
processFunctionBeforeFrameFinalized(MachineFunction &MF) const {
}
void XCoreRegisterInfo::
loadConstant(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
unsigned DstReg, int64_t Value) const {
// TODO use mkmsk if possible.
if (!isImmU16(Value)) {
// TODO use constant pool.
cerr << "loadConstant value too big " << Value << "\n";
abort();
}
int Opcode = isImmU6(Value) ? XCore::LDC_ru6 : XCore::LDC_lru6;
BuildMI(MBB, I, TII.get(Opcode), DstReg).addImm(Value);
}
void XCoreRegisterInfo::
storeToStack(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
unsigned SrcReg, int Offset) const {
assert(Offset%4 == 0 && "Misaligned stack offset");
Offset/=4;
bool isU6 = isImmU6(Offset);
if (!isU6 && !isImmU16(Offset)) {
cerr << "storeToStack offset too big " << Offset << "\n";
abort();
}
int Opcode = isU6 ? XCore::STWSP_ru6 : XCore::STWSP_lru6;
BuildMI(MBB, I, TII.get(Opcode))
.addReg(SrcReg)
.addImm(Offset)
.addImm(0);
}
void XCoreRegisterInfo::
loadFromStack(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
unsigned DstReg, int Offset) const {
assert(Offset%4 == 0 && "Misaligned stack offset");
Offset/=4;
bool isU6 = isImmU6(Offset);
if (!isU6 && !isImmU16(Offset)) {
cerr << "storeToStack offset too big " << Offset << "\n";
abort();
}
int Opcode = isU6 ? XCore::LDWSP_ru6 : XCore::LDWSP_lru6;
BuildMI(MBB, I, TII.get(Opcode), DstReg)
.addImm(Offset)
.addImm(0);
}
void XCoreRegisterInfo::emitPrologue(MachineFunction &MF) const {
MachineBasicBlock &MBB = MF.front(); // Prolog goes in entry BB
MachineBasicBlock::iterator MBBI = MBB.begin();
MachineFrameInfo *MFI = MF.getFrameInfo();
MachineModuleInfo *MMI = MFI->getMachineModuleInfo();
XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
bool FP = hasFP(MF);
// Work out frame sizes.
int FrameSize = MFI->getStackSize();
assert(FrameSize%4 == 0 && "Misaligned frame size");
FrameSize/=4;
bool isU6 = isImmU6(FrameSize);
if (!isU6 && !isImmU16(FrameSize)) {
// FIXME could emit multiple instructions.
cerr << "emitPrologue Frame size too big: " << FrameSize << "\n";
abort();
}
bool emitFrameMoves = needsFrameMoves(MF);
// Do we need to allocate space on the stack?
if (FrameSize) {
bool saveLR = XFI->getUsesLR();
bool LRSavedOnEntry = false;
int Opcode;
if (saveLR && (MFI->getObjectOffset(XFI->getLRSpillSlot()) == 0)) {
Opcode = (isU6) ? XCore::ENTSP_u6 : XCore::ENTSP_lu6;
MBB.addLiveIn(XCore::LR);
saveLR = false;
LRSavedOnEntry = true;
} else {
Opcode = (isU6) ? XCore::EXTSP_u6 : XCore::EXTSP_lu6;
}
BuildMI(MBB, MBBI, TII.get(Opcode)).addImm(FrameSize);
if (emitFrameMoves) {
std::vector<MachineMove> &Moves = MMI->getFrameMoves();
// Show update of SP.
unsigned FrameLabelId = MMI->NextLabelID();
BuildMI(MBB, MBBI, TII.get(XCore::DBG_LABEL)).addImm(FrameLabelId);
MachineLocation SPDst(MachineLocation::VirtualFP);
MachineLocation SPSrc(MachineLocation::VirtualFP, -FrameSize * 4);
Moves.push_back(MachineMove(FrameLabelId, SPDst, SPSrc));
if (LRSavedOnEntry) {
MachineLocation CSDst(MachineLocation::VirtualFP, 0);
MachineLocation CSSrc(XCore::LR);
Moves.push_back(MachineMove(FrameLabelId, CSDst, CSSrc));
}
}
if (saveLR) {
int LRSpillOffset = MFI->getObjectOffset(XFI->getLRSpillSlot());
storeToStack(MBB, MBBI, XCore::LR, LRSpillOffset + FrameSize*4);
MBB.addLiveIn(XCore::LR);
if (emitFrameMoves) {
unsigned SaveLRLabelId = MMI->NextLabelID();
BuildMI(MBB, MBBI, TII.get(XCore::DBG_LABEL)).addImm(SaveLRLabelId);
MachineLocation CSDst(MachineLocation::VirtualFP, LRSpillOffset);
MachineLocation CSSrc(XCore::LR);
MMI->getFrameMoves().push_back(MachineMove(SaveLRLabelId,
CSDst, CSSrc));
}
}
}
if (FP) {
// Save R10 to the stack.
int FPSpillOffset = MFI->getObjectOffset(XFI->getFPSpillSlot());
storeToStack(MBB, MBBI, XCore::R10, FPSpillOffset + FrameSize*4);
// R10 is live-in. It is killed at the spill.
MBB.addLiveIn(XCore::R10);
if (emitFrameMoves) {
unsigned SaveR10LabelId = MMI->NextLabelID();
BuildMI(MBB, MBBI, TII.get(XCore::DBG_LABEL)).addImm(SaveR10LabelId);
MachineLocation CSDst(MachineLocation::VirtualFP, FPSpillOffset);
MachineLocation CSSrc(XCore::R10);
MMI->getFrameMoves().push_back(MachineMove(SaveR10LabelId,
CSDst, CSSrc));
}
// Set the FP from the SP.
unsigned FramePtr = XCore::R10;
BuildMI(MBB, MBBI, TII.get(XCore::LDAWSP_ru6), FramePtr)
.addImm(0)
.addImm(0);
if (emitFrameMoves) {
// Show FP is now valid.
unsigned FrameLabelId = MMI->NextLabelID();
BuildMI(MBB, MBBI, TII.get(XCore::DBG_LABEL)).addImm(FrameLabelId);
MachineLocation SPDst(FramePtr);
MachineLocation SPSrc(MachineLocation::VirtualFP);
MMI->getFrameMoves().push_back(MachineMove(FrameLabelId, SPDst, SPSrc));
}
}
if (emitFrameMoves) {
// Frame moves for callee saved.
std::vector<MachineMove> &Moves = MMI->getFrameMoves();
std::vector<std::pair<unsigned, CalleeSavedInfo> >&SpillLabels =
XFI->getSpillLabels();
for (unsigned I = 0, E = SpillLabels.size(); I != E; ++I) {
unsigned SpillLabel = SpillLabels[I].first;
CalleeSavedInfo &CSI = SpillLabels[I].second;
int Offset = MFI->getObjectOffset(CSI.getFrameIdx());
unsigned Reg = CSI.getReg();
MachineLocation CSDst(MachineLocation::VirtualFP, Offset);
MachineLocation CSSrc(Reg);
Moves.push_back(MachineMove(SpillLabel, CSDst, CSSrc));
}
}
}
void XCoreRegisterInfo::emitEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
MachineFrameInfo *MFI = MF.getFrameInfo();
MachineBasicBlock::iterator MBBI = prior(MBB.end());
bool FP = hasFP(MF);
if (FP) {
// Restore the stack pointer.
unsigned FramePtr = XCore::R10;
BuildMI(MBB, MBBI, TII.get(XCore::SETSP_1r))
.addReg(FramePtr);
}
// Work out frame sizes.
int FrameSize = MFI->getStackSize();
assert(FrameSize%4 == 0 && "Misaligned frame size");
FrameSize/=4;
bool isU6 = isImmU6(FrameSize);
if (!isU6 && !isImmU16(FrameSize)) {
// FIXME could emit multiple instructions.
cerr << "emitEpilogue Frame size too big: " << FrameSize << "\n";
abort();
}
if (FrameSize) {
XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
if (FP) {
// Restore R10
int FPSpillOffset = MFI->getObjectOffset(XFI->getFPSpillSlot());
FPSpillOffset += FrameSize*4;
loadFromStack(MBB, MBBI, XCore::R10, FPSpillOffset);
}
bool restoreLR = XFI->getUsesLR();
if (restoreLR && MFI->getObjectOffset(XFI->getLRSpillSlot()) != 0) {
int LRSpillOffset = MFI->getObjectOffset(XFI->getLRSpillSlot());
LRSpillOffset += FrameSize*4;
loadFromStack(MBB, MBBI, XCore::LR, LRSpillOffset);
restoreLR = false;
}
if (restoreLR) {
// Fold prologue into return instruction
assert(MBBI->getOpcode() == XCore::RETSP_u6
|| MBBI->getOpcode() == XCore::RETSP_lu6);
int Opcode = (isU6) ? XCore::RETSP_u6 : XCore::RETSP_lu6;
BuildMI(MBB, MBBI, TII.get(Opcode)).addImm(FrameSize);
MBB.erase(MBBI);
} else {
int Opcode = (isU6) ? XCore::LDAWSP_ru6_RRegs : XCore::LDAWSP_lru6_RRegs;
BuildMI(MBB, MBBI, TII.get(Opcode), XCore::SP).addImm(FrameSize);
}
}
}
int XCoreRegisterInfo::getDwarfRegNum(unsigned RegNum, bool isEH) const {
return XCoreGenRegisterInfo::getDwarfRegNumFull(RegNum, 0);
}
unsigned XCoreRegisterInfo::getFrameRegister(MachineFunction &MF) const {
bool FP = hasFP(MF);
return FP ? XCore::R10 : XCore::SP;
}
unsigned XCoreRegisterInfo::getRARegister() const {
return XCore::LR;
}
void XCoreRegisterInfo::getInitialFrameState(std::vector<MachineMove> &Moves)
const {
// Initial state of the frame pointer is SP.
MachineLocation Dst(MachineLocation::VirtualFP);
MachineLocation Src(XCore::SP, 0);
Moves.push_back(MachineMove(0, Dst, Src));
}
#include "XCoreGenRegisterInfo.inc"
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