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llvm-project/llvm/lib/Target/Mips/MipsSEFrameLowering.cpp

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//===-- MipsSEFrameLowering.cpp - Mips32/64 Frame 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 Mips32/64 implementation of TargetFrameLowering class.
//
//===----------------------------------------------------------------------===//
#include "MipsSEFrameLowering.h"
#include "MCTargetDesc/MipsBaseInfo.h"
#include "MipsAnalyzeImmediate.h"
#include "MipsMachineFunction.h"
#include "MipsSEInstrInfo.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/IR/DataLayout.h"
#include "llvm/IR/Function.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Target/TargetOptions.h"
using namespace llvm;
namespace {
typedef MachineBasicBlock::iterator Iter;
static std::pair<unsigned, unsigned> getMFHiLoOpc(unsigned Src) {
if (Mips::ACC64RegClass.contains(Src))
return std::make_pair((unsigned)Mips::PseudoMFHI,
(unsigned)Mips::PseudoMFLO);
if (Mips::ACC64DSPRegClass.contains(Src))
return std::make_pair((unsigned)Mips::MFHI_DSP, (unsigned)Mips::MFLO_DSP);
if (Mips::ACC128RegClass.contains(Src))
return std::make_pair((unsigned)Mips::PseudoMFHI64,
(unsigned)Mips::PseudoMFLO64);
return std::make_pair(0, 0);
}
/// Helper class to expand pseudos.
class ExpandPseudo {
public:
ExpandPseudo(MachineFunction &MF);
bool expand();
private:
bool expandInstr(MachineBasicBlock &MBB, Iter I);
void expandLoadCCond(MachineBasicBlock &MBB, Iter I);
void expandStoreCCond(MachineBasicBlock &MBB, Iter I);
void expandLoadACC(MachineBasicBlock &MBB, Iter I, unsigned RegSize);
void expandStoreACC(MachineBasicBlock &MBB, Iter I, unsigned MFHiOpc,
unsigned MFLoOpc, unsigned RegSize);
bool expandCopy(MachineBasicBlock &MBB, Iter I);
bool expandCopyACC(MachineBasicBlock &MBB, Iter I, unsigned MFHiOpc,
unsigned MFLoOpc);
MachineFunction &MF;
MachineRegisterInfo &MRI;
};
}
ExpandPseudo::ExpandPseudo(MachineFunction &MF_)
: MF(MF_), MRI(MF.getRegInfo()) {}
bool ExpandPseudo::expand() {
bool Expanded = false;
for (MachineFunction::iterator BB = MF.begin(), BBEnd = MF.end();
BB != BBEnd; ++BB)
for (Iter I = BB->begin(), End = BB->end(); I != End;)
Expanded |= expandInstr(*BB, I++);
return Expanded;
}
bool ExpandPseudo::expandInstr(MachineBasicBlock &MBB, Iter I) {
switch(I->getOpcode()) {
case Mips::LOAD_CCOND_DSP:
expandLoadCCond(MBB, I);
break;
case Mips::STORE_CCOND_DSP:
expandStoreCCond(MBB, I);
break;
case Mips::LOAD_ACC64:
case Mips::LOAD_ACC64DSP:
expandLoadACC(MBB, I, 4);
break;
case Mips::LOAD_ACC128:
expandLoadACC(MBB, I, 8);
break;
case Mips::STORE_ACC64:
expandStoreACC(MBB, I, Mips::PseudoMFHI, Mips::PseudoMFLO, 4);
break;
case Mips::STORE_ACC64DSP:
expandStoreACC(MBB, I, Mips::MFHI_DSP, Mips::MFLO_DSP, 4);
break;
case Mips::STORE_ACC128:
expandStoreACC(MBB, I, Mips::PseudoMFHI64, Mips::PseudoMFLO64, 8);
break;
case TargetOpcode::COPY:
if (!expandCopy(MBB, I))
return false;
break;
default:
return false;
}
MBB.erase(I);
return true;
}
void ExpandPseudo::expandLoadCCond(MachineBasicBlock &MBB, Iter I) {
// load $vr, FI
// copy ccond, $vr
assert(I->getOperand(0).isReg() && I->getOperand(1).isFI());
const MipsSEInstrInfo &TII =
*static_cast<const MipsSEInstrInfo*>(MF.getTarget().getInstrInfo());
const MipsRegisterInfo &RegInfo =
*static_cast<const MipsRegisterInfo*>(MF.getTarget().getRegisterInfo());
const TargetRegisterClass *RC = RegInfo.intRegClass(4);
unsigned VR = MRI.createVirtualRegister(RC);
unsigned Dst = I->getOperand(0).getReg(), FI = I->getOperand(1).getIndex();
TII.loadRegFromStack(MBB, I, VR, FI, RC, &RegInfo, 0);
BuildMI(MBB, I, I->getDebugLoc(), TII.get(TargetOpcode::COPY), Dst)
.addReg(VR, RegState::Kill);
}
void ExpandPseudo::expandStoreCCond(MachineBasicBlock &MBB, Iter I) {
// copy $vr, ccond
// store $vr, FI
assert(I->getOperand(0).isReg() && I->getOperand(1).isFI());
const MipsSEInstrInfo &TII =
*static_cast<const MipsSEInstrInfo*>(MF.getTarget().getInstrInfo());
const MipsRegisterInfo &RegInfo =
*static_cast<const MipsRegisterInfo*>(MF.getTarget().getRegisterInfo());
const TargetRegisterClass *RC = RegInfo.intRegClass(4);
unsigned VR = MRI.createVirtualRegister(RC);
unsigned Src = I->getOperand(0).getReg(), FI = I->getOperand(1).getIndex();
BuildMI(MBB, I, I->getDebugLoc(), TII.get(TargetOpcode::COPY), VR)
.addReg(Src, getKillRegState(I->getOperand(0).isKill()));
TII.storeRegToStack(MBB, I, VR, true, FI, RC, &RegInfo, 0);
}
void ExpandPseudo::expandLoadACC(MachineBasicBlock &MBB, Iter I,
unsigned RegSize) {
// load $vr0, FI
// copy lo, $vr0
// load $vr1, FI + 4
// copy hi, $vr1
assert(I->getOperand(0).isReg() && I->getOperand(1).isFI());
const MipsSEInstrInfo &TII =
*static_cast<const MipsSEInstrInfo*>(MF.getTarget().getInstrInfo());
const MipsRegisterInfo &RegInfo =
*static_cast<const MipsRegisterInfo*>(MF.getTarget().getRegisterInfo());
const TargetRegisterClass *RC = RegInfo.intRegClass(RegSize);
unsigned VR0 = MRI.createVirtualRegister(RC);
unsigned VR1 = MRI.createVirtualRegister(RC);
unsigned Dst = I->getOperand(0).getReg(), FI = I->getOperand(1).getIndex();
unsigned Lo = RegInfo.getSubReg(Dst, Mips::sub_lo);
unsigned Hi = RegInfo.getSubReg(Dst, Mips::sub_hi);
DebugLoc DL = I->getDebugLoc();
const MCInstrDesc &Desc = TII.get(TargetOpcode::COPY);
TII.loadRegFromStack(MBB, I, VR0, FI, RC, &RegInfo, 0);
BuildMI(MBB, I, DL, Desc, Lo).addReg(VR0, RegState::Kill);
TII.loadRegFromStack(MBB, I, VR1, FI, RC, &RegInfo, RegSize);
BuildMI(MBB, I, DL, Desc, Hi).addReg(VR1, RegState::Kill);
}
void ExpandPseudo::expandStoreACC(MachineBasicBlock &MBB, Iter I,
unsigned MFHiOpc, unsigned MFLoOpc,
unsigned RegSize) {
// mflo $vr0, src
// store $vr0, FI
// mfhi $vr1, src
// store $vr1, FI + 4
assert(I->getOperand(0).isReg() && I->getOperand(1).isFI());
const MipsSEInstrInfo &TII =
*static_cast<const MipsSEInstrInfo*>(MF.getTarget().getInstrInfo());
const MipsRegisterInfo &RegInfo =
*static_cast<const MipsRegisterInfo*>(MF.getTarget().getRegisterInfo());
const TargetRegisterClass *RC = RegInfo.intRegClass(RegSize);
unsigned VR0 = MRI.createVirtualRegister(RC);
unsigned VR1 = MRI.createVirtualRegister(RC);
unsigned Src = I->getOperand(0).getReg(), FI = I->getOperand(1).getIndex();
unsigned SrcKill = getKillRegState(I->getOperand(0).isKill());
DebugLoc DL = I->getDebugLoc();
BuildMI(MBB, I, DL, TII.get(MFLoOpc), VR0).addReg(Src);
TII.storeRegToStack(MBB, I, VR0, true, FI, RC, &RegInfo, 0);
BuildMI(MBB, I, DL, TII.get(MFHiOpc), VR1).addReg(Src, SrcKill);
TII.storeRegToStack(MBB, I, VR1, true, FI, RC, &RegInfo, RegSize);
}
bool ExpandPseudo::expandCopy(MachineBasicBlock &MBB, Iter I) {
unsigned Src = I->getOperand(1).getReg();
std::pair<unsigned, unsigned> Opcodes = getMFHiLoOpc(Src);
if (!Opcodes.first)
return false;
return expandCopyACC(MBB, I, Opcodes.first, Opcodes.second);
}
bool ExpandPseudo::expandCopyACC(MachineBasicBlock &MBB, Iter I,
unsigned MFHiOpc, unsigned MFLoOpc) {
// mflo $vr0, src
// copy dst_lo, $vr0
// mfhi $vr1, src
// copy dst_hi, $vr1
const MipsSEInstrInfo &TII =
*static_cast<const MipsSEInstrInfo*>(MF.getTarget().getInstrInfo());
const MipsRegisterInfo &RegInfo =
*static_cast<const MipsRegisterInfo*>(MF.getTarget().getRegisterInfo());
unsigned Dst = I->getOperand(0).getReg(), Src = I->getOperand(1).getReg();
unsigned VRegSize = RegInfo.getMinimalPhysRegClass(Dst)->getSize() / 2;
const TargetRegisterClass *RC = RegInfo.intRegClass(VRegSize);
unsigned VR0 = MRI.createVirtualRegister(RC);
unsigned VR1 = MRI.createVirtualRegister(RC);
unsigned SrcKill = getKillRegState(I->getOperand(1).isKill());
unsigned DstLo = RegInfo.getSubReg(Dst, Mips::sub_lo);
unsigned DstHi = RegInfo.getSubReg(Dst, Mips::sub_hi);
DebugLoc DL = I->getDebugLoc();
BuildMI(MBB, I, DL, TII.get(MFLoOpc), VR0).addReg(Src);
BuildMI(MBB, I, DL, TII.get(TargetOpcode::COPY), DstLo)
.addReg(VR0, RegState::Kill);
BuildMI(MBB, I, DL, TII.get(MFHiOpc), VR1).addReg(Src, SrcKill);
BuildMI(MBB, I, DL, TII.get(TargetOpcode::COPY), DstHi)
.addReg(VR1, RegState::Kill);
return true;
}
unsigned MipsSEFrameLowering::ehDataReg(unsigned I) const {
static const unsigned EhDataReg[] = {
Mips::A0, Mips::A1, Mips::A2, Mips::A3
};
static const unsigned EhDataReg64[] = {
Mips::A0_64, Mips::A1_64, Mips::A2_64, Mips::A3_64
};
return STI.isABI_N64() ? EhDataReg64[I] : EhDataReg[I];
}
void MipsSEFrameLowering::emitPrologue(MachineFunction &MF) const {
MachineBasicBlock &MBB = MF.front();
MachineFrameInfo *MFI = MF.getFrameInfo();
MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
const MipsSEInstrInfo &TII =
*static_cast<const MipsSEInstrInfo*>(MF.getTarget().getInstrInfo());
const MipsRegisterInfo &RegInfo =
*static_cast<const MipsRegisterInfo*>(MF.getTarget().getRegisterInfo());
MachineBasicBlock::iterator MBBI = MBB.begin();
DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
unsigned SP = STI.isABI_N64() ? Mips::SP_64 : Mips::SP;
unsigned FP = STI.isABI_N64() ? Mips::FP_64 : Mips::FP;
unsigned ZERO = STI.isABI_N64() ? Mips::ZERO_64 : Mips::ZERO;
unsigned ADDu = STI.isABI_N64() ? Mips::DADDu : Mips::ADDu;
// First, compute final stack size.
uint64_t StackSize = MFI->getStackSize();
// No need to allocate space on the stack.
if (StackSize == 0 && !MFI->adjustsStack()) return;
MachineModuleInfo &MMI = MF.getMMI();
const MCRegisterInfo *MRI = MMI.getContext().getRegisterInfo();
MachineLocation DstML, SrcML;
// Adjust stack.
TII.adjustStackPtr(SP, -StackSize, MBB, MBBI);
// emit ".cfi_def_cfa_offset StackSize"
unsigned CFIIndex = MMI.addFrameInst(
MCCFIInstruction::createDefCfaOffset(nullptr, -StackSize));
BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
.addCFIIndex(CFIIndex);
const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
if (CSI.size()) {
// Find the instruction past the last instruction that saves a callee-saved
// register to the stack.
for (unsigned i = 0; i < CSI.size(); ++i)
++MBBI;
// Iterate over list of callee-saved registers and emit .cfi_offset
// directives.
for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
E = CSI.end(); I != E; ++I) {
int64_t Offset = MFI->getObjectOffset(I->getFrameIdx());
unsigned Reg = I->getReg();
// If Reg is a double precision register, emit two cfa_offsets,
// one for each of the paired single precision registers.
if (Mips::AFGR64RegClass.contains(Reg)) {
unsigned Reg0 =
MRI->getDwarfRegNum(RegInfo.getSubReg(Reg, Mips::sub_lo), true);
unsigned Reg1 =
MRI->getDwarfRegNum(RegInfo.getSubReg(Reg, Mips::sub_hi), true);
if (!STI.isLittle())
std::swap(Reg0, Reg1);
unsigned CFIIndex = MMI.addFrameInst(
MCCFIInstruction::createOffset(nullptr, Reg0, Offset));
BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
.addCFIIndex(CFIIndex);
CFIIndex = MMI.addFrameInst(
MCCFIInstruction::createOffset(nullptr, Reg1, Offset + 4));
BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
.addCFIIndex(CFIIndex);
} else {
// Reg is either in GPR32 or FGR32.
unsigned CFIIndex = MMI.addFrameInst(MCCFIInstruction::createOffset(
nullptr, MRI->getDwarfRegNum(Reg, 1), Offset));
BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
.addCFIIndex(CFIIndex);
}
}
}
if (MipsFI->callsEhReturn()) {
const TargetRegisterClass *RC = STI.isABI_N64() ?
&Mips::GPR64RegClass : &Mips::GPR32RegClass;
// Insert instructions that spill eh data registers.
for (int I = 0; I < 4; ++I) {
if (!MBB.isLiveIn(ehDataReg(I)))
MBB.addLiveIn(ehDataReg(I));
TII.storeRegToStackSlot(MBB, MBBI, ehDataReg(I), false,
MipsFI->getEhDataRegFI(I), RC, &RegInfo);
}
// Emit .cfi_offset directives for eh data registers.
for (int I = 0; I < 4; ++I) {
int64_t Offset = MFI->getObjectOffset(MipsFI->getEhDataRegFI(I));
unsigned Reg = MRI->getDwarfRegNum(ehDataReg(I), true);
unsigned CFIIndex = MMI.addFrameInst(
MCCFIInstruction::createOffset(nullptr, Reg, Offset));
BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
.addCFIIndex(CFIIndex);
}
}
// if framepointer enabled, set it to point to the stack pointer.
if (hasFP(MF)) {
// Insert instruction "move $fp, $sp" at this location.
BuildMI(MBB, MBBI, dl, TII.get(ADDu), FP).addReg(SP).addReg(ZERO);
// emit ".cfi_def_cfa_register $fp"
unsigned CFIIndex = MMI.addFrameInst(MCCFIInstruction::createDefCfaRegister(
nullptr, MRI->getDwarfRegNum(FP, true)));
BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
.addCFIIndex(CFIIndex);
}
}
void MipsSEFrameLowering::emitEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
MachineFrameInfo *MFI = MF.getFrameInfo();
MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
const MipsSEInstrInfo &TII =
*static_cast<const MipsSEInstrInfo*>(MF.getTarget().getInstrInfo());
const MipsRegisterInfo &RegInfo =
*static_cast<const MipsRegisterInfo*>(MF.getTarget().getRegisterInfo());
DebugLoc dl = MBBI->getDebugLoc();
unsigned SP = STI.isABI_N64() ? Mips::SP_64 : Mips::SP;
unsigned FP = STI.isABI_N64() ? Mips::FP_64 : Mips::FP;
unsigned ZERO = STI.isABI_N64() ? Mips::ZERO_64 : Mips::ZERO;
unsigned ADDu = STI.isABI_N64() ? Mips::DADDu : Mips::ADDu;
// if framepointer enabled, restore the stack pointer.
if (hasFP(MF)) {
// Find the first instruction that restores a callee-saved register.
MachineBasicBlock::iterator I = MBBI;
for (unsigned i = 0; i < MFI->getCalleeSavedInfo().size(); ++i)
--I;
// Insert instruction "move $sp, $fp" at this location.
BuildMI(MBB, I, dl, TII.get(ADDu), SP).addReg(FP).addReg(ZERO);
}
if (MipsFI->callsEhReturn()) {
const TargetRegisterClass *RC = STI.isABI_N64() ?
&Mips::GPR64RegClass : &Mips::GPR32RegClass;
// Find first instruction that restores a callee-saved register.
MachineBasicBlock::iterator I = MBBI;
for (unsigned i = 0; i < MFI->getCalleeSavedInfo().size(); ++i)
--I;
// Insert instructions that restore eh data registers.
for (int J = 0; J < 4; ++J) {
TII.loadRegFromStackSlot(MBB, I, ehDataReg(J), MipsFI->getEhDataRegFI(J),
RC, &RegInfo);
}
}
// Get the number of bytes from FrameInfo
uint64_t StackSize = MFI->getStackSize();
if (!StackSize)
return;
// Adjust stack.
TII.adjustStackPtr(SP, StackSize, MBB, MBBI);
}
bool MipsSEFrameLowering::
spillCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
const std::vector<CalleeSavedInfo> &CSI,
const TargetRegisterInfo *TRI) const {
MachineFunction *MF = MBB.getParent();
MachineBasicBlock *EntryBlock = MF->begin();
const TargetInstrInfo &TII = *MF->getTarget().getInstrInfo();
for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
// Add the callee-saved register as live-in. Do not add if the register is
// RA and return address is taken, because it has already been added in
// method MipsTargetLowering::LowerRETURNADDR.
// It's killed at the spill, unless the register is RA and return address
// is taken.
unsigned Reg = CSI[i].getReg();
bool IsRAAndRetAddrIsTaken = (Reg == Mips::RA || Reg == Mips::RA_64)
&& MF->getFrameInfo()->isReturnAddressTaken();
if (!IsRAAndRetAddrIsTaken)
EntryBlock->addLiveIn(Reg);
// Insert the spill to the stack frame.
bool IsKill = !IsRAAndRetAddrIsTaken;
const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
TII.storeRegToStackSlot(*EntryBlock, MI, Reg, IsKill,
CSI[i].getFrameIdx(), RC, TRI);
}
return true;
}
bool
MipsSEFrameLowering::hasReservedCallFrame(const MachineFunction &MF) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
// Reserve call frame if the size of the maximum call frame fits into 16-bit
// immediate field and there are no variable sized objects on the stack.
// Make sure the second register scavenger spill slot can be accessed with one
// instruction.
return isInt<16>(MFI->getMaxCallFrameSize() + getStackAlignment()) &&
!MFI->hasVarSizedObjects();
}
// Eliminate ADJCALLSTACKDOWN, ADJCALLSTACKUP pseudo instructions
void MipsSEFrameLowering::
eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
const MipsSEInstrInfo &TII =
*static_cast<const MipsSEInstrInfo*>(MF.getTarget().getInstrInfo());
if (!hasReservedCallFrame(MF)) {
int64_t Amount = I->getOperand(0).getImm();
if (I->getOpcode() == Mips::ADJCALLSTACKDOWN)
Amount = -Amount;
unsigned SP = STI.isABI_N64() ? Mips::SP_64 : Mips::SP;
TII.adjustStackPtr(SP, Amount, MBB, I);
}
MBB.erase(I);
}
void MipsSEFrameLowering::
processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
RegScavenger *RS) const {
MachineRegisterInfo &MRI = MF.getRegInfo();
MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
unsigned FP = STI.isABI_N64() ? Mips::FP_64 : Mips::FP;
// Mark $fp as used if function has dedicated frame pointer.
if (hasFP(MF))
MRI.setPhysRegUsed(FP);
// Create spill slots for eh data registers if function calls eh_return.
if (MipsFI->callsEhReturn())
MipsFI->createEhDataRegsFI();
// Expand pseudo instructions which load, store or copy accumulators.
// Add an emergency spill slot if a pseudo was expanded.
if (ExpandPseudo(MF).expand()) {
// The spill slot should be half the size of the accumulator. If target is
// mips64, it should be 64-bit, otherwise it should be 32-bt.
const TargetRegisterClass *RC = STI.hasMips64() ?
&Mips::GPR64RegClass : &Mips::GPR32RegClass;
int FI = MF.getFrameInfo()->CreateStackObject(RC->getSize(),
RC->getAlignment(), false);
RS->addScavengingFrameIndex(FI);
}
// Set scavenging frame index if necessary.
uint64_t MaxSPOffset = MF.getInfo<MipsFunctionInfo>()->getIncomingArgSize() +
estimateStackSize(MF);
if (isInt<16>(MaxSPOffset))
return;
const TargetRegisterClass *RC = STI.isABI_N64() ?
&Mips::GPR64RegClass : &Mips::GPR32RegClass;
int FI = MF.getFrameInfo()->CreateStackObject(RC->getSize(),
RC->getAlignment(), false);
RS->addScavengingFrameIndex(FI);
}
const MipsFrameLowering *
llvm::createMipsSEFrameLowering(const MipsSubtarget &ST) {
return new MipsSEFrameLowering(ST);
}
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