//===-- PPCRegisterInfo.cpp - PowerPC 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 PowerPC implementation of the TargetRegisterInfo
// class.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "reginfo"
#include "PPCRegisterInfo.h"
#include "PPC.h"
#include "PPCFrameLowering.h"
#include "PPCInstrBuilder.h"
#include "PPCMachineFunctionInfo.h"
#include "PPCSubtarget.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RegisterScavenging.h"
#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Type.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetFrameLowering.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include <cstdlib>
#define GET_REGINFO_TARGET_DESC
#include "PPCGenRegisterInfo.inc"
using namespace llvm;
PPCRegisterInfo::PPCRegisterInfo(const PPCSubtarget &ST,
const TargetInstrInfo &tii)
: PPCGenRegisterInfo(ST.isPPC64() ? PPC::LR8 : PPC::LR,
ST.isPPC64() ? 0 : 1,
ST.isPPC64() ? 0 : 1),
Subtarget(ST), TII(tii) {
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;
// 64-bit
ImmToIdxMap[PPC::LHA8] = PPC::LHAX8; ImmToIdxMap[PPC::LBZ8] = PPC::LBZX8;
ImmToIdxMap[PPC::LHZ8] = PPC::LHZX8; ImmToIdxMap[PPC::LWZ8] = PPC::LWZX8;
ImmToIdxMap[PPC::STB8] = PPC::STBX8; ImmToIdxMap[PPC::STH8] = PPC::STHX8;
ImmToIdxMap[PPC::STW8] = PPC::STWX8; ImmToIdxMap[PPC::STDU] = PPC::STDUX;
ImmToIdxMap[PPC::ADDI8] = PPC::ADD8; ImmToIdxMap[PPC::STD_32] = PPC::STDX_32;
}
/// getPointerRegClass - Return the register class to use to hold pointers.
/// This is used for addressing modes.
const TargetRegisterClass *
PPCRegisterInfo::getPointerRegClass(const MachineFunction &MF, unsigned Kind)
const {
if (Subtarget.isPPC64())
return &PPC::G8RCRegClass;
return &PPC::GPRCRegClass;
}
const uint16_t*
PPCRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
if (Subtarget.isDarwinABI())
return Subtarget.isPPC64() ? CSR_Darwin64_SaveList :
CSR_Darwin32_SaveList;
return Subtarget.isPPC64() ? CSR_SVR464_SaveList : CSR_SVR432_SaveList;
}
const uint32_t*
PPCRegisterInfo::getCallPreservedMask(CallingConv::ID CC) const {
if (Subtarget.isDarwinABI())
return Subtarget.isPPC64() ? CSR_Darwin64_RegMask :
CSR_Darwin32_RegMask;
return Subtarget.isPPC64() ? CSR_SVR464_RegMask : CSR_SVR432_RegMask;
}
BitVector PPCRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
BitVector Reserved(getNumRegs());
const PPCFrameLowering *PPCFI =
static_cast<const PPCFrameLowering*>(MF.getTarget().getFrameLowering());
Reserved.set(PPC::R0);
Reserved.set(PPC::R1);
Reserved.set(PPC::LR);
Reserved.set(PPC::LR8);
Reserved.set(PPC::RM);
// The SVR4 ABI reserves r2 and r13
if (Subtarget.isSVR4ABI()) {
Reserved.set(PPC::R2); // System-reserved register
Reserved.set(PPC::R13); // Small Data Area pointer register
}
// On PPC64, r13 is the thread pointer. Never allocate this register.
// Note that this is over conservative, as it also prevents allocation of R31
// when the FP is not needed.
if (Subtarget.isPPC64()) {
Reserved.set(PPC::R13);
Reserved.set(PPC::R31);
Reserved.set(PPC::X0);
Reserved.set(PPC::X1);
Reserved.set(PPC::X13);
Reserved.set(PPC::X31);
// The 64-bit SVR4 ABI reserves r2 for the TOC pointer.
if (Subtarget.isSVR4ABI()) {
Reserved.set(PPC::X2);
}
}
if (PPCFI->needsFP(MF))
Reserved.set(PPC::R31);
return Reserved;
}
unsigned
PPCRegisterInfo::getRegPressureLimit(const TargetRegisterClass *RC,
MachineFunction &MF) const {
const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
const unsigned DefaultSafety = 1;
switch (RC->getID()) {
default:
return 0;
case PPC::G8RCRegClassID:
case PPC::GPRCRegClassID: {
unsigned FP = TFI->hasFP(MF) ? 1 : 0;
return 32 - FP - DefaultSafety;
}
case PPC::F8RCRegClassID:
case PPC::F4RCRegClassID:
case PPC::VRRCRegClassID:
return 32 - DefaultSafety;
case PPC::CRRCRegClassID:
return 8 - DefaultSafety;
}
}
//===----------------------------------------------------------------------===//
// Stack Frame Processing methods
//===----------------------------------------------------------------------===//
/// lowerDynamicAlloc - Generate the code for allocating an object in the
/// current frame. The sequence of code with be in the general form
///
/// addi R0, SP, \#frameSize ; get the address of the previous frame
/// stwxu R0, SP, Rnegsize ; add and update the SP with the negated size
/// addi Rnew, SP, \#maxCalFrameSize ; get the top of the allocation
///
void PPCRegisterInfo::lowerDynamicAlloc(MachineBasicBlock::iterator II,
int SPAdj, RegScavenger *RS) const {
// Get the instruction.
MachineInstr &MI = *II;
// Get the instruction's basic block.
MachineBasicBlock &MBB = *MI.getParent();
// Get the basic block's function.
MachineFunction &MF = *MBB.getParent();
// Get the frame info.
MachineFrameInfo *MFI = MF.getFrameInfo();
// Determine whether 64-bit pointers are used.
bool LP64 = Subtarget.isPPC64();
DebugLoc dl = MI.getDebugLoc();
// Get the maximum call stack size.
unsigned maxCallFrameSize = MFI->getMaxCallFrameSize();
// Get the total frame size.
unsigned FrameSize = MFI->getStackSize();
// Get stack alignments.
unsigned TargetAlign = MF.getTarget().getFrameLowering()->getStackAlignment();
unsigned MaxAlign = MFI->getMaxAlignment();
if (MaxAlign > TargetAlign)
report_fatal_error("Dynamic alloca with large aligns not supported");
// Determine the previous frame's address. If FrameSize can't be
// represented as 16 bits or we need special alignment, then we load the
// previous frame's address from 0(SP). Why not do an addis of the hi?
// Because R0 is our only safe tmp register and addi/addis treat R0 as zero.
// Constructing the constant and adding would take 3 instructions.
// Fortunately, a frame greater than 32K is rare.
const TargetRegisterClass *G8RC = &PPC::G8RCRegClass;
const TargetRegisterClass *GPRC = &PPC::GPRCRegClass;
unsigned Reg = MF.getRegInfo().createVirtualRegister(LP64 ? G8RC : GPRC);
if (MaxAlign < TargetAlign && isInt<16>(FrameSize)) {
BuildMI(MBB, II, dl, TII.get(PPC::ADDI), Reg)
.addReg(PPC::R31)
.addImm(FrameSize);
} else if (LP64) {
BuildMI(MBB, II, dl, TII.get(PPC::LD), Reg)
.addImm(0)
.addReg(PPC::X1);
} else {
BuildMI(MBB, II, dl, TII.get(PPC::LWZ), Reg)
.addImm(0)
.addReg(PPC::R1);
}
// Grow the stack and update the stack pointer link, then determine the
// address of new allocated space.
if (LP64) {
BuildMI(MBB, II, dl, TII.get(PPC::STDUX), PPC::X1)
.addReg(Reg, RegState::Kill)
.addReg(PPC::X1)
.addReg(MI.getOperand(1).getReg());
if (!MI.getOperand(1).isKill())
BuildMI(MBB, II, dl, TII.get(PPC::ADDI8), MI.getOperand(0).getReg())
.addReg(PPC::X1)
.addImm(maxCallFrameSize);
else
// Implicitly kill the register.
BuildMI(MBB, II, dl, TII.get(PPC::ADDI8), MI.getOperand(0).getReg())
.addReg(PPC::X1)
.addImm(maxCallFrameSize)
.addReg(MI.getOperand(1).getReg(), RegState::ImplicitKill);
} else {
BuildMI(MBB, II, dl, TII.get(PPC::STWUX), PPC::R1)
.addReg(Reg, RegState::Kill)
.addReg(PPC::R1)
.addReg(MI.getOperand(1).getReg());
if (!MI.getOperand(1).isKill())
BuildMI(MBB, II, dl, TII.get(PPC::ADDI), MI.getOperand(0).getReg())
.addReg(PPC::R1)
.addImm(maxCallFrameSize);
else
// Implicitly kill the register.
BuildMI(MBB, II, dl, TII.get(PPC::ADDI), MI.getOperand(0).getReg())
.addReg(PPC::R1)
.addImm(maxCallFrameSize)
.addReg(MI.getOperand(1).getReg(), RegState::ImplicitKill);
}
// Discard the DYNALLOC instruction.
MBB.erase(II);
}
/// lowerCRSpilling - Generate the code for spilling a CR register. Instead of
/// reserving a whole register (R0), we scrounge for one here. This generates
/// code like this:
///
/// mfcr rA ; Move the conditional register into GPR rA.
/// rlwinm rA, rA, SB, 0, 31 ; Shift the bits left so they are in CR0's slot.
/// stw rA, FI ; Store rA to the frame.
///
void PPCRegisterInfo::lowerCRSpilling(MachineBasicBlock::iterator II,
unsigned FrameIndex, int SPAdj,
RegScavenger *RS) const {
// Get the instruction.
MachineInstr &MI = *II; // ; SPILL_CR <SrcReg>, <offset>
// Get the instruction's basic block.
MachineBasicBlock &MBB = *MI.getParent();
DebugLoc dl = MI.getDebugLoc();
// FIXME: Once LLVM supports creating virtual registers here, or the register
// scavenger can return multiple registers, stop using reserved registers
// here.
(void) SPAdj;
(void) RS;
bool LP64 = Subtarget.isPPC64();
unsigned Reg = LP64 ? PPC::X0 : PPC::R0;
unsigned SrcReg = MI.getOperand(0).getReg();
// We need to store the CR in the low 4-bits of the saved value. First, issue
// an MFCRpsued to save all of the CRBits and, if needed, kill the SrcReg.
BuildMI(MBB, II, dl, TII.get(LP64 ? PPC::MFCR8pseud : PPC::MFCRpseud), Reg)
.addReg(SrcReg, getKillRegState(MI.getOperand(0).isKill()));
// If the saved register wasn't CR0, shift the bits left so that they are in
// CR0's slot.
if (SrcReg != PPC::CR0)
// rlwinm rA, rA, ShiftBits, 0, 31.
BuildMI(MBB, II, dl, TII.get(LP64 ? PPC::RLWINM8 : PPC::RLWINM), Reg)
.addReg(Reg, RegState::Kill)
.addImm(getPPCRegisterNumbering(SrcReg) * 4)
.addImm(0)
.addImm(31);
addFrameReference(BuildMI(MBB, II, dl, TII.get(LP64 ? PPC::STW8 : PPC::STW))
.addReg(Reg, getKillRegState(MI.getOperand(1).getImm())),
FrameIndex);
// Discard the pseudo instruction.
MBB.erase(II);
}
void PPCRegisterInfo::lowerCRRestore(MachineBasicBlock::iterator II,
unsigned FrameIndex, int SPAdj,
RegScavenger *RS) const {
// Get the instruction.
MachineInstr &MI = *II; // ; <DestReg> = RESTORE_CR <offset>
// Get the instruction's basic block.
MachineBasicBlock &MBB = *MI.getParent();
DebugLoc dl = MI.getDebugLoc();
// FIXME: Once LLVM supports creating virtual registers here, or the register
// scavenger can return multiple registers, stop using reserved registers
// here.
(void) SPAdj;
(void) RS;
bool LP64 = Subtarget.isPPC64();
unsigned Reg = LP64 ? PPC::X0 : PPC::R0;
unsigned DestReg = MI.getOperand(0).getReg();
assert(MI.definesRegister(DestReg) &&
"RESTORE_CR does not define its destination");
addFrameReference(BuildMI(MBB, II, dl, TII.get(LP64 ? PPC::LWZ8 : PPC::LWZ),
Reg), FrameIndex);
// If the reloaded register isn't CR0, shift the bits right so that they are
// in the right CR's slot.
if (DestReg != PPC::CR0) {
unsigned ShiftBits = getPPCRegisterNumbering(DestReg)*4;
// rlwinm r11, r11, 32-ShiftBits, 0, 31.
BuildMI(MBB, II, dl, TII.get(LP64 ? PPC::RLWINM8 : PPC::RLWINM), Reg)
.addReg(Reg).addImm(32-ShiftBits).addImm(0)
.addImm(31);
}
BuildMI(MBB, II, dl, TII.get(LP64 ? PPC::MTCRF8 : PPC::MTCRF), DestReg)
.addReg(Reg);
// Discard the pseudo instruction.
MBB.erase(II);
}
bool
PPCRegisterInfo::hasReservedSpillSlot(const MachineFunction &MF,
unsigned Reg, int &FrameIdx) const {
// For the nonvolatile condition registers (CR2, CR3, CR4) in an SVR4
// ABI, return true to prevent allocating an additional frame slot.
// For 64-bit, the CR save area is at SP+8; the value of FrameIdx = 0
// is arbitrary and will be subsequently ignored. For 32-bit, we have
// previously created the stack slot if needed, so return its FrameIdx.
if (Subtarget.isSVR4ABI() && PPC::CR2 <= Reg && Reg <= PPC::CR4) {
if (Subtarget.isPPC64())
FrameIdx = 0;
else {
const PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
FrameIdx = FI->getCRSpillFrameIndex();
}
return true;
}
return false;
}
void
PPCRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
int SPAdj, unsigned FIOperandNum,
RegScavenger *RS) const {
assert(SPAdj == 0 && "Unexpected");
// Get the instruction.
MachineInstr &MI = *II;
// Get the instruction's basic block.
MachineBasicBlock &MBB = *MI.getParent();
// Get the basic block's function.
MachineFunction &MF = *MBB.getParent();
// Get the frame info.
MachineFrameInfo *MFI = MF.getFrameInfo();
const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
DebugLoc dl = MI.getDebugLoc();
// Take into account whether it's an add or mem instruction
unsigned OffsetOperandNo = (FIOperandNum == 2) ? 1 : 2;
if (MI.isInlineAsm())
OffsetOperandNo = FIOperandNum-1;
// Get the frame index.
int FrameIndex = MI.getOperand(FIOperandNum).getIndex();
// Get the frame pointer save index. Users of this index are primarily
// DYNALLOC instructions.
PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
int FPSI = FI->getFramePointerSaveIndex();
// Get the instruction opcode.
unsigned OpC = MI.getOpcode();
// Special case for dynamic alloca.
if (FPSI && FrameIndex == FPSI &&
(OpC == PPC::DYNALLOC || OpC == PPC::DYNALLOC8)) {
lowerDynamicAlloc(II, SPAdj, RS);
return;
}
// Special case for pseudo-ops SPILL_CR and RESTORE_CR.
if (OpC == PPC::SPILL_CR) {
lowerCRSpilling(II, FrameIndex, SPAdj, RS);
return;
} else if (OpC == PPC::RESTORE_CR) {
lowerCRRestore(II, FrameIndex, SPAdj, RS);
return;
}
// Replace the FrameIndex with base register with GPR1 (SP) or GPR31 (FP).
bool is64Bit = Subtarget.isPPC64();
MI.getOperand(FIOperandNum).ChangeToRegister(TFI->hasFP(MF) ?
(is64Bit ? PPC::X31 : PPC::R31) :
(is64Bit ? PPC::X1 : PPC::R1),
false);
// Figure out if the offset in the instruction is shifted right two bits. This
// is true for instructions like "STD", which the machine implicitly adds two
// low zeros to.
bool isIXAddr = false;
switch (OpC) {
case PPC::LWA:
case PPC::LD:
case PPC::STD:
case PPC::STD_32:
isIXAddr = true;
break;
}
bool noImmForm = false;
switch (OpC) {
case PPC::LVEBX:
case PPC::LVEHX:
case PPC::LVEWX:
case PPC::LVX:
case PPC::LVXL:
case PPC::LVSL:
case PPC::LVSR:
case PPC::STVEBX:
case PPC::STVEHX:
case PPC::STVEWX:
case PPC::STVX:
case PPC::STVXL:
noImmForm = true;
break;
}
// Now add the frame object offset to the offset from r1.
int Offset = MFI->getObjectOffset(FrameIndex);
if (!isIXAddr)
Offset += MI.getOperand(OffsetOperandNo).getImm();
else
Offset += MI.getOperand(OffsetOperandNo).getImm() << 2;
// 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.
// Naked functions have stack size 0, although getStackSize may not reflect that
// because we didn't call all the pieces that compute it for naked functions.
if (!MF.getFunction()->getAttributes().
hasAttribute(AttributeSet::FunctionIndex, Attribute::Naked))
Offset += MFI->getStackSize();
// If we can, encode the offset directly into the instruction. If this is a
// normal PPC "ri" instruction, any 16-bit value can be safely encoded. If
// this is a PPC64 "ix" instruction, only a 16-bit value with the low two bits
// clear can be encoded. This is extremely uncommon, because normally you
// only "std" to a stack slot that is at least 4-byte aligned, but it can
// happen in invalid code.
if (OpC == PPC::DBG_VALUE || // DBG_VALUE is always Reg+Imm
(!noImmForm &&
isInt<16>(Offset) && (!isIXAddr || (Offset & 3) == 0))) {
if (isIXAddr)
Offset >>= 2; // The actual encoded value has the low two bits zero.
MI.getOperand(OffsetOperandNo).ChangeToImmediate(Offset);
return;
}
// The offset doesn't fit into a single register, scavenge one to build the
// offset in.
const TargetRegisterClass *G8RC = &PPC::G8RCRegClass;
const TargetRegisterClass *GPRC = &PPC::GPRCRegClass;
unsigned SReg = MF.getRegInfo().createVirtualRegister(is64Bit ? G8RC : GPRC);
// Insert a set of rA with the full offset value before the ld, st, or add
BuildMI(MBB, II, dl, TII.get(is64Bit ? PPC::LIS8 : PPC::LIS), SReg)
.addImm(Offset >> 16);
BuildMI(MBB, II, dl, TII.get(is64Bit ? PPC::ORI8 : PPC::ORI), SReg)
.addReg(SReg, RegState::Kill)
.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
unsigned OperandBase;
if (noImmForm)
OperandBase = 1;
else if (OpC != TargetOpcode::INLINEASM) {
assert(ImmToIdxMap.count(OpC) &&
"No indexed form of load or store available!");
unsigned NewOpcode = ImmToIdxMap.find(OpC)->second;
MI.setDesc(TII.get(NewOpcode));
OperandBase = 1;
} else {
OperandBase = OffsetOperandNo;
}
unsigned StackReg = MI.getOperand(FIOperandNum).getReg();
MI.getOperand(OperandBase).ChangeToRegister(StackReg, false);
MI.getOperand(OperandBase + 1).ChangeToRegister(SReg, false, false, true);
}
unsigned PPCRegisterInfo::getFrameRegister(const MachineFunction &MF) const {
const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
if (!Subtarget.isPPC64())
return TFI->hasFP(MF) ? PPC::R31 : PPC::R1;
else
return TFI->hasFP(MF) ? PPC::X31 : PPC::X1;
}
unsigned PPCRegisterInfo::getEHExceptionRegister() const {
return !Subtarget.isPPC64() ? PPC::R3 : PPC::X3;
}
unsigned PPCRegisterInfo::getEHHandlerRegister() const {
return !Subtarget.isPPC64() ? PPC::R4 : PPC::X4;
}