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llvm-6502/lib/Target/PowerPC/PPCRegisterInfo.cpp

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//===- PPCRegisterInfo.cpp - PowerPC Register Information -------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the PowerPC implementation of the MRegisterInfo class.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "reginfo"
#include "PPC.h"
#include "PPCInstrBuilder.h"
#include "PPCRegisterInfo.h"
#include "llvm/Constants.h"
#include "llvm/Type.h"
#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/Target/TargetFrameInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/ADT/STLExtras.h"
#include <cstdlib>
#include <iostream>
using namespace llvm;
PPCRegisterInfo::PPCRegisterInfo()
: PPCGenRegisterInfo(PPC::ADJCALLSTACKDOWN, PPC::ADJCALLSTACKUP) {
ImmToIdxMap[PPC::LD] = PPC::LDX; ImmToIdxMap[PPC::STD] = PPC::STDX;
ImmToIdxMap[PPC::LBZ] = PPC::LBZX; ImmToIdxMap[PPC::STB] = PPC::STBX;
ImmToIdxMap[PPC::LHZ] = PPC::LHZX; ImmToIdxMap[PPC::LHA] = PPC::LHAX;
ImmToIdxMap[PPC::LWZ] = PPC::LWZX; ImmToIdxMap[PPC::LWA] = PPC::LWAX;
ImmToIdxMap[PPC::LFS] = PPC::LFSX; ImmToIdxMap[PPC::LFD] = PPC::LFDX;
ImmToIdxMap[PPC::STH] = PPC::STHX; ImmToIdxMap[PPC::STW] = PPC::STWX;
ImmToIdxMap[PPC::STFS] = PPC::STFSX; ImmToIdxMap[PPC::STFD] = PPC::STFDX;
ImmToIdxMap[PPC::ADDI] = PPC::ADD4;
}
void
PPCRegisterInfo::storeRegToStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
unsigned SrcReg, int FrameIdx,
const TargetRegisterClass *RC) const {
if (SrcReg == PPC::LR) {
BuildMI(MBB, MI, PPC::MFLR, 1, PPC::R11);
addFrameReference(BuildMI(MBB, MI, PPC::STW, 3).addReg(PPC::R11), FrameIdx);
} else if (RC == PPC::CRRCRegisterClass) {
BuildMI(MBB, MI, PPC::MFCR, 0, PPC::R11);
addFrameReference(BuildMI(MBB, MI, PPC::STW, 3).addReg(PPC::R11), FrameIdx);
} else if (RC == PPC::GPRCRegisterClass) {
addFrameReference(BuildMI(MBB, MI, PPC::STW, 3).addReg(SrcReg),FrameIdx);
} else if (RC == PPC::G8RCRegisterClass) {
addFrameReference(BuildMI(MBB, MI, PPC::STD, 3).addReg(SrcReg),FrameIdx);
} else if (RC == PPC::F8RCRegisterClass) {
addFrameReference(BuildMI(MBB, MI, PPC::STFD, 3).addReg(SrcReg),FrameIdx);
} else if (RC == PPC::F4RCRegisterClass) {
addFrameReference(BuildMI(MBB, MI, PPC::STFS, 3).addReg(SrcReg),FrameIdx);
} else {
assert(0 && "Unknown regclass!");
abort();
}
}
void
PPCRegisterInfo::loadRegFromStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
unsigned DestReg, int FrameIdx,
const TargetRegisterClass *RC) const {
if (DestReg == PPC::LR) {
addFrameReference(BuildMI(MBB, MI, PPC::LWZ, 2, PPC::R11), FrameIdx);
BuildMI(MBB, MI, PPC::MTLR, 1).addReg(PPC::R11);
} else if (RC == PPC::CRRCRegisterClass) {
addFrameReference(BuildMI(MBB, MI, PPC::LWZ, 2, PPC::R11), FrameIdx);
BuildMI(MBB, MI, PPC::MTCRF, 1, DestReg).addReg(PPC::R11);
} else if (RC == PPC::GPRCRegisterClass) {
addFrameReference(BuildMI(MBB, MI, PPC::LWZ, 2, DestReg), FrameIdx);
} else if (RC == PPC::G8RCRegisterClass) {
addFrameReference(BuildMI(MBB, MI, PPC::LD, 2, DestReg), FrameIdx);
} else if (RC == PPC::F8RCRegisterClass) {
addFrameReference(BuildMI(MBB, MI, PPC::LFD, 2, DestReg), FrameIdx);
} else if (RC == PPC::F4RCRegisterClass) {
addFrameReference(BuildMI(MBB, MI, PPC::LFS, 2, DestReg), FrameIdx);
} else {
assert(0 && "Unknown regclass!");
abort();
}
}
void PPCRegisterInfo::copyRegToReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
unsigned DestReg, unsigned SrcReg,
const TargetRegisterClass *RC) const {
MachineInstr *I;
if (RC == PPC::GPRCRegisterClass) {
BuildMI(MBB, MI, PPC::OR4, 2, DestReg).addReg(SrcReg).addReg(SrcReg);
} else if (RC == PPC::G8RCRegisterClass) {
BuildMI(MBB, MI, PPC::OR8, 2, DestReg).addReg(SrcReg).addReg(SrcReg);
} else if (RC == PPC::F4RCRegisterClass) {
BuildMI(MBB, MI, PPC::FMRS, 1, DestReg).addReg(SrcReg);
} else if (RC == PPC::F8RCRegisterClass) {
BuildMI(MBB, MI, PPC::FMRD, 1, DestReg).addReg(SrcReg);
} else if (RC == PPC::CRRCRegisterClass) {
BuildMI(MBB, MI, PPC::MCRF, 1, DestReg).addReg(SrcReg);
} else {
std::cerr << "Attempt to copy register that is not GPR or FPR";
abort();
}
}
/// foldMemoryOperand - PowerPC (like most RISC's) can only fold spills into
/// copy instructions, turning them into load/store instructions.
MachineInstr *PPCRegisterInfo::foldMemoryOperand(MachineInstr *MI,
unsigned OpNum,
int FrameIndex) const {
// Make sure this is a reg-reg copy. Note that we can't handle MCRF, because
// it takes more than one instruction to store it.
unsigned Opc = MI->getOpcode();
if ((Opc == PPC::OR4 &&
MI->getOperand(1).getReg() == MI->getOperand(2).getReg())) {
if (OpNum == 0) { // move -> store
unsigned InReg = MI->getOperand(1).getReg();
return addFrameReference(BuildMI(PPC::STW,
3).addReg(InReg), FrameIndex);
} else { // move -> load
unsigned OutReg = MI->getOperand(0).getReg();
return addFrameReference(BuildMI(PPC::LWZ, 2, OutReg), FrameIndex);
}
} else if ((Opc == PPC::OR8 &&
MI->getOperand(1).getReg() == MI->getOperand(2).getReg())) {
if (OpNum == 0) { // move -> store
unsigned InReg = MI->getOperand(1).getReg();
return addFrameReference(BuildMI(PPC::STD,
3).addReg(InReg), FrameIndex);
} else { // move -> load
unsigned OutReg = MI->getOperand(0).getReg();
return addFrameReference(BuildMI(PPC::LD, 2, OutReg), FrameIndex);
}
} else if (Opc == PPC::FMRD) {
if (OpNum == 0) { // move -> store
unsigned InReg = MI->getOperand(1).getReg();
return addFrameReference(BuildMI(PPC::STFD,
3).addReg(InReg), FrameIndex);
} else { // move -> load
unsigned OutReg = MI->getOperand(0).getReg();
return addFrameReference(BuildMI(PPC::LFD, 2, OutReg), FrameIndex);
}
} else if (Opc == PPC::FMRS) {
if (OpNum == 0) { // move -> store
unsigned InReg = MI->getOperand(1).getReg();
return addFrameReference(BuildMI(PPC::STFS,
3).addReg(InReg), FrameIndex);
} else { // move -> load
unsigned OutReg = MI->getOperand(0).getReg();
return addFrameReference(BuildMI(PPC::LFS, 2, OutReg), FrameIndex);
}
}
return 0;
}
//===----------------------------------------------------------------------===//
// Stack Frame Processing methods
//===----------------------------------------------------------------------===//
// hasFP - Return true if the specified function should have a dedicated frame
// pointer register. This is true if the function has variable sized allocas or
// if frame pointer elimination is disabled.
//
static bool hasFP(MachineFunction &MF) {
return NoFramePointerElim || MF.getFrameInfo()->hasVarSizedObjects();
}
void PPCRegisterInfo::
eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
if (hasFP(MF)) {
// If we have a frame pointer, convert as follows:
// ADJCALLSTACKDOWN -> addi, r1, r1, -amount
// ADJCALLSTACKUP -> addi, r1, r1, amount
MachineInstr *Old = I;
unsigned Amount = Old->getOperand(0).getImmedValue();
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;
// Replace the pseudo instruction with a new instruction...
if (Old->getOpcode() == PPC::ADJCALLSTACKDOWN) {
BuildMI(MBB, I, PPC::ADDI, 2, PPC::R1).addReg(PPC::R1).addSImm(-Amount);
} else {
assert(Old->getOpcode() == PPC::ADJCALLSTACKUP);
BuildMI(MBB, I, PPC::ADDI, 2, PPC::R1).addReg(PPC::R1).addSImm(Amount);
}
}
}
MBB.erase(I);
}
void
PPCRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II) const {
unsigned i = 0;
MachineInstr &MI = *II;
MachineBasicBlock &MBB = *MI.getParent();
MachineFunction &MF = *MBB.getParent();
while (!MI.getOperand(i).isFrameIndex()) {
++i;
assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
}
int FrameIndex = MI.getOperand(i).getFrameIndex();
// Replace the FrameIndex with base register with GPR1 (SP) or GPR31 (FP).
MI.SetMachineOperandReg(i, hasFP(MF) ? PPC::R31 : PPC::R1);
// Take into account whether it's an add or mem instruction
unsigned OffIdx = (i == 2) ? 1 : 2;
// Now add the frame object offset to the offset from r1.
int Offset = MF.getFrameInfo()->getObjectOffset(FrameIndex) +
MI.getOperand(OffIdx).getImmedValue();
// If we're not using a Frame Pointer that has been set to the value of the
// SP before having the stack size subtracted from it, then add the stack size
// to Offset to get the correct offset.
Offset += MF.getFrameInfo()->getStackSize();
if (Offset > 32767 || Offset < -32768) {
// Insert a set of r0 with the full offset value before the ld, st, or add
MachineBasicBlock *MBB = MI.getParent();
BuildMI(*MBB, II, PPC::LIS, 1, PPC::R0).addSImm(Offset >> 16);
BuildMI(*MBB, II, PPC::ORI, 2, PPC::R0).addReg(PPC::R0).addImm(Offset);
// convert into indexed form of the instruction
// sth 0:rA, 1:imm 2:(rB) ==> sthx 0:rA, 2:rB, 1:r0
// addi 0:rA 1:rB, 2, imm ==> add 0:rA, 1:rB, 2:r0
assert(ImmToIdxMap.count(MI.getOpcode()) &&
"No indexed form of load or store available!");
unsigned NewOpcode = ImmToIdxMap.find(MI.getOpcode())->second;
MI.setOpcode(NewOpcode);
MI.SetMachineOperandReg(1, MI.getOperand(i).getReg());
MI.SetMachineOperandReg(2, PPC::R0);
} else {
switch (MI.getOpcode()) {
case PPC::LWA:
case PPC::LD:
case PPC::STD:
case PPC::STDU:
assert((Offset & 3) == 0 && "Invalid frame offset!");
Offset >>= 2; // The actual encoded value has the low two bits zero.
break;
}
MI.SetMachineOperandConst(OffIdx, MachineOperand::MO_SignExtendedImmed,
Offset);
}
}
void PPCRegisterInfo::emitPrologue(MachineFunction &MF) const {
MachineBasicBlock &MBB = MF.front(); // Prolog goes in entry BB
MachineBasicBlock::iterator MBBI = MBB.begin();
MachineFrameInfo *MFI = MF.getFrameInfo();
// Get the number of bytes to allocate from the FrameInfo
unsigned NumBytes = MFI->getStackSize();
// Get the alignments provided by the target, and the maximum alignment
// (if any) of the fixed frame objects.
unsigned TargetAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
unsigned MaxAlign = MFI->getMaxAlignment();
// If we have calls, we cannot use the red zone to store callee save registers
// and we must set up a stack frame, so calculate the necessary size here.
if (MFI->hasCalls()) {
// We reserve argument space for call sites in the function immediately on
// entry to the current function. This eliminates the need for add/sub
// brackets around call sites.
NumBytes += MFI->getMaxCallFrameSize();
}
// If we are a leaf function, and use up to 224 bytes of stack space,
// and don't have a frame pointer, then we do not need to adjust the stack
// pointer (we fit in the Red Zone).
if ((NumBytes == 0) || (NumBytes <= 224 && !hasFP(MF) && !MFI->hasCalls() &&
MaxAlign <= TargetAlign)) {
MFI->setStackSize(0);
return;
}
// Add the size of R1 to NumBytes size for the store of R1 to the bottom
// of the stack and round the size to a multiple of the alignment.
unsigned Align = std::max(TargetAlign, MaxAlign);
unsigned GPRSize = 4;
unsigned Size = hasFP(MF) ? GPRSize + GPRSize : GPRSize;
NumBytes = (NumBytes+Size+Align-1)/Align*Align;
// Update frame info to pretend that this is part of the stack...
MFI->setStackSize(NumBytes);
// Adjust stack pointer: r1 -= numbytes.
if (NumBytes <= 32768) {
BuildMI(MBB, MBBI, PPC::STWU, 3)
.addReg(PPC::R1).addSImm(-NumBytes).addReg(PPC::R1);
} else {
int NegNumbytes = -NumBytes;
BuildMI(MBB, MBBI, PPC::LIS, 1, PPC::R0).addSImm(NegNumbytes >> 16);
BuildMI(MBB, MBBI, PPC::ORI, 2, PPC::R0)
.addReg(PPC::R0).addImm(NegNumbytes & 0xFFFF);
BuildMI(MBB, MBBI, PPC::STWUX, 3)
.addReg(PPC::R1).addReg(PPC::R1).addReg(PPC::R0);
}
// If there is a preferred stack alignment, align R1 now
// FIXME: If this ever matters, this could be made more efficient by folding
// this into the code above, so that we don't issue two store+update
// instructions.
if (MaxAlign > TargetAlign) {
assert(isPowerOf2_32(MaxAlign) && MaxAlign < 32767 && "Invalid alignment!");
BuildMI(MBB, MBBI, PPC::RLWINM, 4, PPC::R0)
.addReg(PPC::R1).addImm(0).addImm(32-Log2_32(MaxAlign)).addImm(31);
BuildMI(MBB, MBBI, PPC::SUBFIC, 2,PPC::R0).addReg(PPC::R0).addImm(MaxAlign);
BuildMI(MBB, MBBI, PPC::STWUX, 3)
.addReg(PPC::R1).addReg(PPC::R1).addReg(PPC::R0);
}
// If there is a frame pointer, copy R1 (SP) into R31 (FP)
if (hasFP(MF)) {
BuildMI(MBB, MBBI, PPC::STW, 3)
.addReg(PPC::R31).addSImm(GPRSize).addReg(PPC::R1);
BuildMI(MBB, MBBI, PPC::OR4, 2, PPC::R31).addReg(PPC::R1).addReg(PPC::R1);
}
}
void PPCRegisterInfo::emitEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
MachineBasicBlock::iterator MBBI = prior(MBB.end());
assert(MBBI->getOpcode() == PPC::BLR &&
"Can only insert epilog into returning blocks");
// Get the number of bytes allocated from the FrameInfo.
unsigned NumBytes = MF.getFrameInfo()->getStackSize();
unsigned GPRSize = 4;
if (NumBytes != 0) {
// If this function has a frame pointer, load the saved stack pointer from
// its stack slot.
if (hasFP(MF)) {
BuildMI(MBB, MBBI, PPC::LWZ, 2, PPC::R31)
.addSImm(GPRSize).addReg(PPC::R31);
}
// The loaded (or persistent) stack pointer value is offseted by the 'stwu'
// on entry to the function. Add this offset back now.
if (NumBytes < 32768) {
BuildMI(MBB, MBBI, PPC::ADDI, 2, PPC::R1)
.addReg(PPC::R1).addSImm(NumBytes);
} else {
BuildMI(MBB, MBBI, PPC::LIS, 1, PPC::R0).addSImm(NumBytes >> 16);
BuildMI(MBB, MBBI, PPC::ORI, 2, PPC::R0)
.addReg(PPC::R0).addImm(NumBytes & 0xFFFF);
BuildMI(MBB, MBBI, PPC::ADD4, 2, PPC::R1)
.addReg(PPC::R0).addReg(PPC::R1);
}
}
}
#include "PPCGenRegisterInfo.inc"
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