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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 "MipsMachineFunction.h"
#include "MipsSEInstrInfo.h"
#include "MipsSubtarget.h"
#include "llvm/ADT/StringSwitch.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/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);
bool expandBuildPairF64(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I, bool FP64) const;
bool expandExtractElementF64(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I, bool FP64) const;
MachineFunction &MF;
MachineRegisterInfo &MRI;
const MipsSubtarget &Subtarget;
const MipsSEInstrInfo &TII;
const MipsRegisterInfo &RegInfo;
};
}
ExpandPseudo::ExpandPseudo(MachineFunction &MF_)
: MF(MF_), MRI(MF.getRegInfo()),
Subtarget(static_cast<const MipsSubtarget &>(MF.getSubtarget())),
TII(*static_cast<const MipsSEInstrInfo *>(Subtarget.getInstrInfo())),
RegInfo(*Subtarget.getRegisterInfo()) {}
bool ExpandPseudo::expand() {
bool Expanded = false;
for (auto &MBB : MF) {
for (Iter I = MBB.begin(), End = MBB.end(); I != End;)
Expanded |= expandInstr(MBB, 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 Mips::BuildPairF64:
if (expandBuildPairF64(MBB, I, false))
MBB.erase(I);
return false;
case Mips::BuildPairF64_64:
if (expandBuildPairF64(MBB, I, true))
MBB.erase(I);
return false;
case Mips::ExtractElementF64:
if (expandExtractElementF64(MBB, I, false))
MBB.erase(I);
return false;
case Mips::ExtractElementF64_64:
if (expandExtractElementF64(MBB, I, true))
MBB.erase(I);
return false;
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 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 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 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 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
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;
}
/// This method expands the same instruction that MipsSEInstrInfo::
/// expandBuildPairF64 does, for the case when ABI is fpxx and mthc1 is not
/// available and the case where the ABI is FP64A. It is implemented here
/// because frame indexes are eliminated before MipsSEInstrInfo::
/// expandBuildPairF64 is called.
bool ExpandPseudo::expandBuildPairF64(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
bool FP64) const {
// For fpxx and when mthc1 is not available, use:
// spill + reload via ldc1
//
// The case where dmtc1 is available doesn't need to be handled here
// because it never creates a BuildPairF64 node.
//
// The FP64A ABI (fp64 with nooddspreg) must also use a spill/reload sequence
// for odd-numbered double precision values (because the lower 32-bits is
// transferred with mtc1 which is redirected to the upper half of the even
// register). Unfortunately, we have to make this decision before register
// allocation so for now we use a spill/reload sequence for all
// double-precision values in regardless of being an odd/even register.
if ((Subtarget.isABI_FPXX() && !Subtarget.hasMTHC1()) ||
(FP64 && !Subtarget.useOddSPReg())) {
unsigned DstReg = I->getOperand(0).getReg();
unsigned LoReg = I->getOperand(1).getReg();
unsigned HiReg = I->getOperand(2).getReg();
// It should be impossible to have FGR64 on MIPS-II or MIPS32r1 (which are
// the cases where mthc1 is not available). 64-bit architectures and
// MIPS32r2 or later can use FGR64 though.
assert(Subtarget.isGP64bit() || Subtarget.hasMTHC1() ||
!Subtarget.isFP64bit());
const TargetRegisterClass *RC = &Mips::GPR32RegClass;
const TargetRegisterClass *RC2 =
FP64 ? &Mips::FGR64RegClass : &Mips::AFGR64RegClass;
// We re-use the same spill slot each time so that the stack frame doesn't
// grow too much in functions with a large number of moves.
int FI = MF.getInfo<MipsFunctionInfo>()->getMoveF64ViaSpillFI(RC2);
if (!Subtarget.isLittle())
std::swap(LoReg, HiReg);
TII.storeRegToStack(MBB, I, LoReg, I->getOperand(1).isKill(), FI, RC,
&RegInfo, 0);
TII.storeRegToStack(MBB, I, HiReg, I->getOperand(2).isKill(), FI, RC,
&RegInfo, 4);
TII.loadRegFromStack(MBB, I, DstReg, FI, RC2, &RegInfo, 0);
return true;
}
return false;
}
/// This method expands the same instruction that MipsSEInstrInfo::
/// expandExtractElementF64 does, for the case when ABI is fpxx and mfhc1 is not
/// available and the case where the ABI is FP64A. It is implemented here
/// because frame indexes are eliminated before MipsSEInstrInfo::
/// expandExtractElementF64 is called.
bool ExpandPseudo::expandExtractElementF64(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
bool FP64) const {
const MachineOperand &Op1 = I->getOperand(1);
const MachineOperand &Op2 = I->getOperand(2);
if ((Op1.isReg() && Op1.isUndef()) || (Op2.isReg() && Op2.isUndef())) {
unsigned DstReg = I->getOperand(0).getReg();
BuildMI(MBB, I, I->getDebugLoc(), TII.get(Mips::IMPLICIT_DEF), DstReg);
return true;
}
// For fpxx and when mfhc1 is not available, use:
// spill + reload via ldc1
//
// The case where dmfc1 is available doesn't need to be handled here
// because it never creates a ExtractElementF64 node.
//
// The FP64A ABI (fp64 with nooddspreg) must also use a spill/reload sequence
// for odd-numbered double precision values (because the lower 32-bits is
// transferred with mfc1 which is redirected to the upper half of the even
// register). Unfortunately, we have to make this decision before register
// allocation so for now we use a spill/reload sequence for all
// double-precision values in regardless of being an odd/even register.
if ((Subtarget.isABI_FPXX() && !Subtarget.hasMTHC1()) ||
(FP64 && !Subtarget.useOddSPReg())) {
unsigned DstReg = I->getOperand(0).getReg();
unsigned SrcReg = Op1.getReg();
unsigned N = Op2.getImm();
int64_t Offset = 4 * (Subtarget.isLittle() ? N : (1 - N));
// It should be impossible to have FGR64 on MIPS-II or MIPS32r1 (which are
// the cases where mfhc1 is not available). 64-bit architectures and
// MIPS32r2 or later can use FGR64 though.
assert(Subtarget.isGP64bit() || Subtarget.hasMTHC1() ||
!Subtarget.isFP64bit());
const TargetRegisterClass *RC =
FP64 ? &Mips::FGR64RegClass : &Mips::AFGR64RegClass;
const TargetRegisterClass *RC2 = &Mips::GPR32RegClass;
// We re-use the same spill slot each time so that the stack frame doesn't
// grow too much in functions with a large number of moves.
int FI = MF.getInfo<MipsFunctionInfo>()->getMoveF64ViaSpillFI(RC);
TII.storeRegToStack(MBB, I, SrcReg, Op1.isKill(), FI, RC, &RegInfo, 0);
TII.loadRegFromStack(MBB, I, DstReg, FI, RC2, &RegInfo, Offset);
return true;
}
return false;
}
MipsSEFrameLowering::MipsSEFrameLowering(const MipsSubtarget &STI)
: MipsFrameLowering(STI, STI.stackAlignment()) {}
void MipsSEFrameLowering::emitPrologue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
assert(&MF.front() == &MBB && "Shrink-wrapping not yet supported");
MachineFrameInfo *MFI = MF.getFrameInfo();
MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
const MipsSEInstrInfo &TII =
*static_cast<const MipsSEInstrInfo *>(STI.getInstrInfo());
const MipsRegisterInfo &RegInfo =
*static_cast<const MipsRegisterInfo *>(STI.getRegisterInfo());
MachineBasicBlock::iterator MBBI = MBB.begin();
DebugLoc dl;
MipsABIInfo ABI = STI.getABI();
unsigned SP = ABI.GetStackPtr();
unsigned FP = ABI.GetFramePtr();
unsigned ZERO = ABI.GetNullPtr();
unsigned MOVE = ABI.GetGPRMoveOp();
unsigned ADDiu = ABI.GetPtrAddiuOp();
unsigned AND = ABI.IsN64() ? Mips::AND64 : Mips::AND;
const TargetRegisterClass *RC = ABI.ArePtrs64bit() ?
&Mips::GPR64RegClass : &Mips::GPR32RegClass;
// 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);
if (MF.getFunction()->hasFnAttribute("interrupt"))
emitInterruptPrologueStub(MF, MBB);
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 if (Mips::FGR64RegClass.contains(Reg)) {
unsigned Reg0 = MRI->getDwarfRegNum(Reg, true);
unsigned Reg1 = MRI->getDwarfRegNum(Reg, true) + 1;
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()) {
// Insert instructions that spill eh data registers.
for (int I = 0; I < 4; ++I) {
if (!MBB.isLiveIn(ABI.GetEhDataReg(I)))
MBB.addLiveIn(ABI.GetEhDataReg(I));
TII.storeRegToStackSlot(MBB, MBBI, ABI.GetEhDataReg(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(ABI.GetEhDataReg(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(MOVE), FP).addReg(SP).addReg(ZERO)
.setMIFlag(MachineInstr::FrameSetup);
// 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);
if (RegInfo.needsStackRealignment(MF)) {
// addiu $Reg, $zero, -MaxAlignment
// andi $sp, $sp, $Reg
unsigned VR = MF.getRegInfo().createVirtualRegister(RC);
assert(isInt<16>(MFI->getMaxAlignment()) &&
"Function's alignment size requirement is not supported.");
int MaxAlign = - (signed) MFI->getMaxAlignment();
BuildMI(MBB, MBBI, dl, TII.get(ADDiu), VR).addReg(ZERO) .addImm(MaxAlign);
BuildMI(MBB, MBBI, dl, TII.get(AND), SP).addReg(SP).addReg(VR);
if (hasBP(MF)) {
// move $s7, $sp
unsigned BP = STI.isABI_N64() ? Mips::S7_64 : Mips::S7;
BuildMI(MBB, MBBI, dl, TII.get(MOVE), BP)
.addReg(SP)
.addReg(ZERO);
}
}
}
}
void MipsSEFrameLowering::emitInterruptPrologueStub(
MachineFunction &MF, MachineBasicBlock &MBB) const {
MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
MachineBasicBlock::iterator MBBI = MBB.begin();
DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
// Report an error the target doesn't support Mips32r2 or later.
// The epilogue relies on the use of the "ehb" to clear execution
// hazards. Pre R2 Mips relies on an implementation defined number
// of "ssnop"s to clear the execution hazard. Support for ssnop hazard
// clearing is not provided so reject that configuration.
if (!STI.hasMips32r2())
report_fatal_error(
"\"interrupt\" attribute is not supported on pre-MIPS32R2 or "
"MIPS16 targets.");
// The GP register contains the "user" value, so we cannot perform
// any gp relative loads until we restore the "kernel" or "system" gp
// value. Until support is written we shall only accept the static
// relocation model.
if ((STI.getRelocationModel() != Reloc::Static))
report_fatal_error("\"interrupt\" attribute is only supported for the "
"static relocation model on MIPS at the present time.");
if (!STI.isABI_O32() || STI.hasMips64())
report_fatal_error("\"interrupt\" attribute is only supported for the "
"O32 ABI on MIPS32R2+ at the present time.");
// Perform ISR handling like GCC
StringRef IntKind =
MF.getFunction()->getFnAttribute("interrupt").getValueAsString();
const TargetRegisterClass *PtrRC = &Mips::GPR32RegClass;
// EIC interrupt handling needs to read the Cause register to disable
// interrupts.
if (IntKind == "eic") {
// Coprocessor registers are always live per se.
MBB.addLiveIn(Mips::COP013);
BuildMI(MBB, MBBI, DL, STI.getInstrInfo()->get(Mips::MFC0), Mips::K0)
.addReg(Mips::COP013)
.addImm(0)
.setMIFlag(MachineInstr::FrameSetup);
BuildMI(MBB, MBBI, DL, STI.getInstrInfo()->get(Mips::EXT), Mips::K0)
.addReg(Mips::K0)
.addImm(10)
.addImm(6)
.setMIFlag(MachineInstr::FrameSetup);
}
// Fetch and spill EPC
MBB.addLiveIn(Mips::COP014);
BuildMI(MBB, MBBI, DL, STI.getInstrInfo()->get(Mips::MFC0), Mips::K1)
.addReg(Mips::COP014)
.addImm(0)
.setMIFlag(MachineInstr::FrameSetup);
STI.getInstrInfo()->storeRegToStack(MBB, MBBI, Mips::K1, false,
MipsFI->getISRRegFI(0), PtrRC,
STI.getRegisterInfo(), 0);
// Fetch and Spill Status
MBB.addLiveIn(Mips::COP012);
BuildMI(MBB, MBBI, DL, STI.getInstrInfo()->get(Mips::MFC0), Mips::K1)
.addReg(Mips::COP012)
.addImm(0)
.setMIFlag(MachineInstr::FrameSetup);
STI.getInstrInfo()->storeRegToStack(MBB, MBBI, Mips::K1, false,
MipsFI->getISRRegFI(1), PtrRC,
STI.getRegisterInfo(), 0);
// Build the configuration for disabling lower priority interrupts. Non EIC
// interrupts need to be masked off with zero, EIC from the Cause register.
unsigned InsPosition = 8;
unsigned InsSize = 0;
unsigned SrcReg = Mips::ZERO;
// If the interrupt we're tied to is the EIC, switch the source for the
// masking off interrupts to the cause register.
if (IntKind == "eic") {
SrcReg = Mips::K0;
InsPosition = 10;
InsSize = 6;
} else
InsSize = StringSwitch<unsigned>(IntKind)
.Case("sw0", 1)
.Case("sw1", 2)
.Case("hw0", 3)
.Case("hw1", 4)
.Case("hw2", 5)
.Case("hw3", 6)
.Case("hw4", 7)
.Case("hw5", 8)
.Default(0);
assert(InsSize != 0 && "Unknown interrupt type!");
BuildMI(MBB, MBBI, DL, STI.getInstrInfo()->get(Mips::INS), Mips::K1)
.addReg(SrcReg)
.addImm(InsPosition)
.addImm(InsSize)
.addReg(Mips::K1)
.setMIFlag(MachineInstr::FrameSetup);
// Mask off KSU, ERL, EXL
BuildMI(MBB, MBBI, DL, STI.getInstrInfo()->get(Mips::INS), Mips::K1)
.addReg(Mips::ZERO)
.addImm(1)
.addImm(4)
.addReg(Mips::K1)
.setMIFlag(MachineInstr::FrameSetup);
// Disable the FPU as we are not spilling those register sets.
if (!STI.useSoftFloat())
BuildMI(MBB, MBBI, DL, STI.getInstrInfo()->get(Mips::INS), Mips::K1)
.addReg(Mips::ZERO)
.addImm(29)
.addImm(1)
.addReg(Mips::K1)
.setMIFlag(MachineInstr::FrameSetup);
// Set the new status
BuildMI(MBB, MBBI, DL, STI.getInstrInfo()->get(Mips::MTC0), Mips::COP012)
.addReg(Mips::K1)
.addImm(0)
.setMIFlag(MachineInstr::FrameSetup);
}
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 *>(STI.getInstrInfo());
const MipsRegisterInfo &RegInfo =
*static_cast<const MipsRegisterInfo *>(STI.getRegisterInfo());
DebugLoc DL = MBBI->getDebugLoc();
MipsABIInfo ABI = STI.getABI();
unsigned SP = ABI.GetStackPtr();
unsigned FP = ABI.GetFramePtr();
unsigned ZERO = ABI.GetNullPtr();
unsigned MOVE = ABI.GetGPRMoveOp();
// 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(MOVE), SP).addReg(FP).addReg(ZERO);
}
if (MipsFI->callsEhReturn()) {
const TargetRegisterClass *RC =
ABI.ArePtrs64bit() ? &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, ABI.GetEhDataReg(J),
MipsFI->getEhDataRegFI(J), RC, &RegInfo);
}
}
if (MF.getFunction()->hasFnAttribute("interrupt"))
emitInterruptEpilogueStub(MF, MBB);
// Get the number of bytes from FrameInfo
uint64_t StackSize = MFI->getStackSize();
if (!StackSize)
return;
// Adjust stack.
TII.adjustStackPtr(SP, StackSize, MBB, MBBI);
}
void MipsSEFrameLowering::emitInterruptEpilogueStub(
MachineFunction &MF, MachineBasicBlock &MBB) const {
MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
// Perform ISR handling like GCC
const TargetRegisterClass *PtrRC = &Mips::GPR32RegClass;
// Disable Interrupts.
BuildMI(MBB, MBBI, DL, STI.getInstrInfo()->get(Mips::DI), Mips::ZERO);
BuildMI(MBB, MBBI, DL, STI.getInstrInfo()->get(Mips::EHB));
// Restore EPC
STI.getInstrInfo()->loadRegFromStackSlot(MBB, MBBI, Mips::K1,
MipsFI->getISRRegFI(0), PtrRC,
STI.getRegisterInfo());
BuildMI(MBB, MBBI, DL, STI.getInstrInfo()->get(Mips::MTC0), Mips::COP014)
.addReg(Mips::K1)
.addImm(0);
// Restore Status
STI.getInstrInfo()->loadRegFromStackSlot(MBB, MBBI, Mips::K1,
MipsFI->getISRRegFI(1), PtrRC,
STI.getRegisterInfo());
BuildMI(MBB, MBBI, DL, STI.getInstrInfo()->get(Mips::MTC0), Mips::COP012)
.addReg(Mips::K1)
.addImm(0);
}
int MipsSEFrameLowering::getFrameIndexReference(const MachineFunction &MF,
int FI,
unsigned &FrameReg) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
MipsABIInfo ABI = STI.getABI();
if (MFI->isFixedObjectIndex(FI))
FrameReg = hasFP(MF) ? ABI.GetFramePtr() : ABI.GetStackPtr();
else
FrameReg = hasBP(MF) ? ABI.GetBasePtr() : ABI.GetStackPtr();
return MFI->getObjectOffset(FI) + MFI->getStackSize() -
getOffsetOfLocalArea() + MFI->getOffsetAdjustment();
}
bool MipsSEFrameLowering::
spillCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
const std::vector<CalleeSavedInfo> &CSI,
const TargetRegisterInfo *TRI) const {
MachineFunction *MF = MBB.getParent();
MachineBasicBlock *EntryBlock = &MF->front();
const TargetInstrInfo &TII = *STI.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);
// ISRs require HI/LO to be spilled into kernel registers to be then
// spilled to the stack frame.
bool IsLOHI = (Reg == Mips::LO0 || Reg == Mips::LO0_64 ||
Reg == Mips::HI0 || Reg == Mips::HI0_64);
const Function *Func = MBB.getParent()->getFunction();
if (IsLOHI && Func->hasFnAttribute("interrupt")) {
DebugLoc DL = MI->getDebugLoc();
unsigned Op = 0;
if (!STI.getABI().ArePtrs64bit()) {
Op = (Reg == Mips::HI0) ? Mips::MFHI : Mips::MFLO;
Reg = Mips::K0;
} else {
Op = (Reg == Mips::HI0) ? Mips::MFHI64 : Mips::MFLO64;
Reg = Mips::K0_64;
}
BuildMI(MBB, MI, DL, TII.get(Op), Mips::K0)
.setMIFlag(MachineInstr::FrameSetup);
}
// 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();
}
/// Mark \p Reg and all registers aliasing it in the bitset.
static void setAliasRegs(MachineFunction &MF, BitVector &SavedRegs,
unsigned Reg) {
const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo();
for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
SavedRegs.set(*AI);
}
void MipsSEFrameLowering::determineCalleeSaves(MachineFunction &MF,
BitVector &SavedRegs,
RegScavenger *RS) const {
TargetFrameLowering::determineCalleeSaves(MF, SavedRegs, RS);
MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
MipsABIInfo ABI = STI.getABI();
unsigned FP = ABI.GetFramePtr();
unsigned BP = ABI.IsN64() ? Mips::S7_64 : Mips::S7;
// Mark $fp as used if function has dedicated frame pointer.
if (hasFP(MF))
setAliasRegs(MF, SavedRegs, FP);
// Mark $s7 as used if function has dedicated base pointer.
if (hasBP(MF))
setAliasRegs(MF, SavedRegs, BP);
// Create spill slots for eh data registers if function calls eh_return.
if (MipsFI->callsEhReturn())
MipsFI->createEhDataRegsFI();
// Create spill slots for Coprocessor 0 registers if function is an ISR.
if (MipsFI->isISR())
MipsFI->createISRRegFI();
// 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 =
ABI.ArePtrs64bit() ? &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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