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llvm-project/llvm/lib/Target/Mips/Mips16InstrInfo.cpp

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//===-- Mips16InstrInfo.cpp - Mips16 Instruction 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 Mips16 implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//
#include "Mips16InstrInfo.h"
#include "InstPrinter/MipsInstPrinter.h"
#include "MipsMachineFunction.h"
#include "MipsTargetMachine.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RegisterScavenging.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/TargetRegistry.h"
#include <cctype>
using namespace llvm;
static cl::opt<bool> NeverUseSaveRestore(
"mips16-never-use-save-restore",
cl::init(false),
cl::desc("For testing ability to adjust stack pointer "
"without save/restore instruction"),
cl::Hidden);
Mips16InstrInfo::Mips16InstrInfo(MipsTargetMachine &tm)
: MipsInstrInfo(tm, Mips::Bimm16),
RI(*tm.getSubtargetImpl()) {}
const MipsRegisterInfo &Mips16InstrInfo::getRegisterInfo() const {
return RI;
}
/// isLoadFromStackSlot - If the specified machine instruction is a direct
/// load from a stack slot, return the virtual or physical register number of
/// the destination along with the FrameIndex of the loaded stack slot. If
/// not, return 0. This predicate must return 0 if the instruction has
/// any side effects other than loading from the stack slot.
unsigned Mips16InstrInfo::
isLoadFromStackSlot(const MachineInstr *MI, int &FrameIndex) const
{
return 0;
}
/// isStoreToStackSlot - If the specified machine instruction is a direct
/// store to a stack slot, return the virtual or physical register number of
/// the source reg along with the FrameIndex of the loaded stack slot. If
/// not, return 0. This predicate must return 0 if the instruction has
/// any side effects other than storing to the stack slot.
unsigned Mips16InstrInfo::
isStoreToStackSlot(const MachineInstr *MI, int &FrameIndex) const
{
return 0;
}
void Mips16InstrInfo::copyPhysReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I, DebugLoc DL,
unsigned DestReg, unsigned SrcReg,
bool KillSrc) const {
unsigned Opc = 0;
if (Mips::CPU16RegsRegClass.contains(DestReg) &&
Mips::GPR32RegClass.contains(SrcReg))
Opc = Mips::MoveR3216;
else if (Mips::GPR32RegClass.contains(DestReg) &&
Mips::CPU16RegsRegClass.contains(SrcReg))
Opc = Mips::Move32R16;
else if ((SrcReg == Mips::HI0) &&
(Mips::CPU16RegsRegClass.contains(DestReg)))
Opc = Mips::Mfhi16, SrcReg = 0;
else if ((SrcReg == Mips::LO0) &&
(Mips::CPU16RegsRegClass.contains(DestReg)))
Opc = Mips::Mflo16, SrcReg = 0;
assert(Opc && "Cannot copy registers");
MachineInstrBuilder MIB = BuildMI(MBB, I, DL, get(Opc));
if (DestReg)
MIB.addReg(DestReg, RegState::Define);
if (SrcReg)
MIB.addReg(SrcReg, getKillRegState(KillSrc));
}
void Mips16InstrInfo::
storeRegToStack(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
unsigned SrcReg, bool isKill, int FI,
const TargetRegisterClass *RC, const TargetRegisterInfo *TRI,
int64_t Offset) const {
DebugLoc DL;
if (I != MBB.end()) DL = I->getDebugLoc();
MachineMemOperand *MMO = GetMemOperand(MBB, FI, MachineMemOperand::MOStore);
unsigned Opc = 0;
if (Mips::CPU16RegsRegClass.hasSubClassEq(RC))
Opc = Mips::SwRxSpImmX16;
assert(Opc && "Register class not handled!");
BuildMI(MBB, I, DL, get(Opc)).addReg(SrcReg, getKillRegState(isKill)).
addFrameIndex(FI).addImm(Offset)
.addMemOperand(MMO);
}
void Mips16InstrInfo::
loadRegFromStack(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
unsigned DestReg, int FI, const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI, int64_t Offset) const {
DebugLoc DL;
if (I != MBB.end()) DL = I->getDebugLoc();
MachineMemOperand *MMO = GetMemOperand(MBB, FI, MachineMemOperand::MOLoad);
unsigned Opc = 0;
if (Mips::CPU16RegsRegClass.hasSubClassEq(RC))
Opc = Mips::LwRxSpImmX16;
assert(Opc && "Register class not handled!");
BuildMI(MBB, I, DL, get(Opc), DestReg).addFrameIndex(FI).addImm(Offset)
.addMemOperand(MMO);
}
bool Mips16InstrInfo::expandPostRAPseudo(MachineBasicBlock::iterator MI) const {
MachineBasicBlock &MBB = *MI->getParent();
switch(MI->getDesc().getOpcode()) {
default:
return false;
case Mips::RetRA16:
ExpandRetRA16(MBB, MI, Mips::JrcRa16);
break;
}
MBB.erase(MI);
return true;
}
/// GetOppositeBranchOpc - Return the inverse of the specified
/// opcode, e.g. turning BEQ to BNE.
unsigned Mips16InstrInfo::getOppositeBranchOpc(unsigned Opc) const {
switch (Opc) {
default: llvm_unreachable("Illegal opcode!");
case Mips::BeqzRxImmX16: return Mips::BnezRxImmX16;
case Mips::BnezRxImmX16: return Mips::BeqzRxImmX16;
case Mips::BeqzRxImm16: return Mips::BnezRxImm16;
case Mips::BnezRxImm16: return Mips::BeqzRxImm16;
case Mips::BteqzT8CmpX16: return Mips::BtnezT8CmpX16;
case Mips::BteqzT8SltX16: return Mips::BtnezT8SltX16;
case Mips::BteqzT8SltiX16: return Mips::BtnezT8SltiX16;
case Mips::Btnez16: return Mips::Bteqz16;
case Mips::BtnezX16: return Mips::BteqzX16;
case Mips::BtnezT8CmpiX16: return Mips::BteqzT8CmpiX16;
case Mips::BtnezT8SltuX16: return Mips::BteqzT8SltuX16;
case Mips::BtnezT8SltiuX16: return Mips::BteqzT8SltiuX16;
case Mips::Bteqz16: return Mips::Btnez16;
case Mips::BteqzX16: return Mips::BtnezX16;
case Mips::BteqzT8CmpiX16: return Mips::BtnezT8CmpiX16;
case Mips::BteqzT8SltuX16: return Mips::BtnezT8SltuX16;
case Mips::BteqzT8SltiuX16: return Mips::BtnezT8SltiuX16;
case Mips::BtnezT8CmpX16: return Mips::BteqzT8CmpX16;
case Mips::BtnezT8SltX16: return Mips::BteqzT8SltX16;
case Mips::BtnezT8SltiX16: return Mips::BteqzT8SltiX16;
}
assert(false && "Implement this function.");
return 0;
}
// Adjust SP by FrameSize bytes. Save RA, S0, S1
void Mips16InstrInfo::makeFrame(unsigned SP, int64_t FrameSize,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
DebugLoc DL = I != MBB.end() ? I->getDebugLoc() : DebugLoc();
if (!NeverUseSaveRestore) {
if (isUInt<11>(FrameSize))
BuildMI(MBB, I, DL, get(Mips::SaveRaF16)).addImm(FrameSize);
else {
int Base = 2040; // should create template function like isUInt that
// returns largest possible n bit unsigned integer
int64_t Remainder = FrameSize - Base;
BuildMI(MBB, I, DL, get(Mips::SaveRaF16)). addImm(Base);
if (isInt<16>(-Remainder))
BuildAddiuSpImm(MBB, I, -Remainder);
else
adjustStackPtrBig(SP, -Remainder, MBB, I, Mips::V0, Mips::V1);
}
}
else {
//
// sw ra, -4[sp]
// sw s1, -8[sp]
// sw s0, -12[sp]
MachineInstrBuilder MIB1 = BuildMI(MBB, I, DL, get(Mips::SwRxSpImmX16),
Mips::RA);
MIB1.addReg(Mips::SP);
MIB1.addImm(-4);
MachineInstrBuilder MIB2 = BuildMI(MBB, I, DL, get(Mips::SwRxSpImmX16),
Mips::S1);
MIB2.addReg(Mips::SP);
MIB2.addImm(-8);
MachineInstrBuilder MIB3 = BuildMI(MBB, I, DL, get(Mips::SwRxSpImmX16),
Mips::S0);
MIB3.addReg(Mips::SP);
MIB3.addImm(-12);
adjustStackPtrBig(SP, -FrameSize, MBB, I, Mips::V0, Mips::V1);
}
}
// Adjust SP by FrameSize bytes. Restore RA, S0, S1
void Mips16InstrInfo::restoreFrame(unsigned SP, int64_t FrameSize,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
DebugLoc DL = I != MBB.end() ? I->getDebugLoc() : DebugLoc();
if (!NeverUseSaveRestore) {
if (isUInt<11>(FrameSize))
BuildMI(MBB, I, DL, get(Mips::RestoreRaF16)).addImm(FrameSize);
else {
int Base = 2040; // should create template function like isUInt that
// returns largest possible n bit unsigned integer
int64_t Remainder = FrameSize - Base;
if (isInt<16>(Remainder))
BuildAddiuSpImm(MBB, I, Remainder);
else
adjustStackPtrBig(SP, Remainder, MBB, I, Mips::A0, Mips::A1);
BuildMI(MBB, I, DL, get(Mips::RestoreRaF16)). addImm(Base);
}
}
else {
adjustStackPtrBig(SP, FrameSize, MBB, I, Mips::A0, Mips::A1);
// lw ra, -4[sp]
// lw s1, -8[sp]
// lw s0, -12[sp]
MachineInstrBuilder MIB1 = BuildMI(MBB, I, DL, get(Mips::LwRxSpImmX16),
Mips::A0);
MIB1.addReg(Mips::SP);
MIB1.addImm(-4);
MachineInstrBuilder MIB0 = BuildMI(MBB, I, DL, get(Mips::Move32R16),
Mips::RA);
MIB0.addReg(Mips::A0);
MachineInstrBuilder MIB2 = BuildMI(MBB, I, DL, get(Mips::LwRxSpImmX16),
Mips::S1);
MIB2.addReg(Mips::SP);
MIB2.addImm(-8);
MachineInstrBuilder MIB3 = BuildMI(MBB, I, DL, get(Mips::LwRxSpImmX16),
Mips::S0);
MIB3.addReg(Mips::SP);
MIB3.addImm(-12);
}
}
// Adjust SP by Amount bytes where bytes can be up to 32bit number.
// This can only be called at times that we know that there is at least one free
// register.
// This is clearly safe at prologue and epilogue.
//
void Mips16InstrInfo::adjustStackPtrBig(unsigned SP, int64_t Amount,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
unsigned Reg1, unsigned Reg2) const {
DebugLoc DL = I != MBB.end() ? I->getDebugLoc() : DebugLoc();
// MachineRegisterInfo &RegInfo = MBB.getParent()->getRegInfo();
// unsigned Reg1 = RegInfo.createVirtualRegister(&Mips::CPU16RegsRegClass);
// unsigned Reg2 = RegInfo.createVirtualRegister(&Mips::CPU16RegsRegClass);
//
// li reg1, constant
// move reg2, sp
// add reg1, reg1, reg2
// move sp, reg1
//
//
MachineInstrBuilder MIB1 = BuildMI(MBB, I, DL, get(Mips::LwConstant32), Reg1);
MIB1.addImm(Amount).addImm(-1);
MachineInstrBuilder MIB2 = BuildMI(MBB, I, DL, get(Mips::MoveR3216), Reg2);
MIB2.addReg(Mips::SP, RegState::Kill);
MachineInstrBuilder MIB3 = BuildMI(MBB, I, DL, get(Mips::AdduRxRyRz16), Reg1);
MIB3.addReg(Reg1);
MIB3.addReg(Reg2, RegState::Kill);
MachineInstrBuilder MIB4 = BuildMI(MBB, I, DL, get(Mips::Move32R16),
Mips::SP);
MIB4.addReg(Reg1, RegState::Kill);
}
void Mips16InstrInfo::adjustStackPtrBigUnrestricted(unsigned SP, int64_t Amount,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
assert(false && "adjust stack pointer amount exceeded");
}
/// Adjust SP by Amount bytes.
void Mips16InstrInfo::adjustStackPtr(unsigned SP, int64_t Amount,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
if (isInt<16>(Amount)) // need to change to addiu sp, ....and isInt<16>
BuildAddiuSpImm(MBB, I, Amount);
else
adjustStackPtrBigUnrestricted(SP, Amount, MBB, I);
}
/// This function generates the sequence of instructions needed to get the
/// result of adding register REG and immediate IMM.
unsigned
Mips16InstrInfo::loadImmediate(unsigned FrameReg,
int64_t Imm, MachineBasicBlock &MBB,
MachineBasicBlock::iterator II, DebugLoc DL,
unsigned &NewImm) const {
//
// given original instruction is:
// Instr rx, T[offset] where offset is too big.
//
// lo = offset & 0xFFFF
// hi = ((offset >> 16) + (lo >> 15)) & 0xFFFF;
//
// let T = temporary register
// li T, hi
// shl T, 16
// add T, Rx, T
//
RegScavenger rs;
int32_t lo = Imm & 0xFFFF;
NewImm = lo;
int Reg =0;
int SpReg = 0;
rs.enterBasicBlock(&MBB);
rs.forward(II);
//
// We need to know which registers can be used, in the case where there
// are not enough free registers. We exclude all registers that
// are used in the instruction that we are helping.
// // Consider all allocatable registers in the register class initially
BitVector Candidates =
RI.getAllocatableSet
(*II->getParent()->getParent(), &Mips::CPU16RegsRegClass);
// Exclude all the registers being used by the instruction.
for (unsigned i = 0, e = II->getNumOperands(); i != e; ++i) {
MachineOperand &MO = II->getOperand(i);
if (MO.isReg() && MO.getReg() != 0 && !MO.isDef() &&
!TargetRegisterInfo::isVirtualRegister(MO.getReg()))
Candidates.reset(MO.getReg());
}
//
// If the same register was used and defined in an instruction, then
// it will not be in the list of candidates.
//
// we need to analyze the instruction that we are helping.
// we need to know if it defines register x but register x is not
// present as an operand of the instruction. this tells
// whether the register is live before the instruction. if it's not
// then we don't need to save it in case there are no free registers.
//
int DefReg = 0;
for (unsigned i = 0, e = II->getNumOperands(); i != e; ++i) {
MachineOperand &MO = II->getOperand(i);
if (MO.isReg() && MO.isDef()) {
DefReg = MO.getReg();
break;
}
}
//
BitVector Available = rs.getRegsAvailable(&Mips::CPU16RegsRegClass);
Available &= Candidates;
//
// we use T0 for the first register, if we need to save something away.
// we use T1 for the second register, if we need to save something away.
//
unsigned FirstRegSaved =0, SecondRegSaved=0;
unsigned FirstRegSavedTo = 0, SecondRegSavedTo = 0;
Reg = Available.find_first();
if (Reg == -1) {
Reg = Candidates.find_first();
Candidates.reset(Reg);
if (DefReg != Reg) {
FirstRegSaved = Reg;
FirstRegSavedTo = Mips::T0;
copyPhysReg(MBB, II, DL, FirstRegSavedTo, FirstRegSaved, true);
}
}
else
Available.reset(Reg);
BuildMI(MBB, II, DL, get(Mips::LwConstant32), Reg).addImm(Imm).addImm(-1);
NewImm = 0;
if (FrameReg == Mips::SP) {
SpReg = Available.find_first();
if (SpReg == -1) {
SpReg = Candidates.find_first();
// Candidates.reset(SpReg); // not really needed
if (DefReg!= SpReg) {
SecondRegSaved = SpReg;
SecondRegSavedTo = Mips::T1;
}
if (SecondRegSaved)
copyPhysReg(MBB, II, DL, SecondRegSavedTo, SecondRegSaved, true);
}
else
Available.reset(SpReg);
copyPhysReg(MBB, II, DL, SpReg, Mips::SP, false);
BuildMI(MBB, II, DL, get(Mips:: AdduRxRyRz16), Reg).addReg(SpReg, RegState::Kill)
.addReg(Reg);
}
else
BuildMI(MBB, II, DL, get(Mips:: AdduRxRyRz16), Reg).addReg(FrameReg)
.addReg(Reg, RegState::Kill);
if (FirstRegSaved || SecondRegSaved) {
II = llvm::next(II);
if (FirstRegSaved)
copyPhysReg(MBB, II, DL, FirstRegSaved, FirstRegSavedTo, true);
if (SecondRegSaved)
copyPhysReg(MBB, II, DL, SecondRegSaved, SecondRegSavedTo, true);
}
return Reg;
}
/// This function generates the sequence of instructions needed to get the
/// result of adding register REG and immediate IMM.
unsigned
Mips16InstrInfo::basicLoadImmediate(
unsigned FrameReg,
int64_t Imm, MachineBasicBlock &MBB,
MachineBasicBlock::iterator II, DebugLoc DL,
unsigned &NewImm) const {
const TargetRegisterClass *RC = &Mips::CPU16RegsRegClass;
MachineRegisterInfo &RegInfo = MBB.getParent()->getRegInfo();
unsigned Reg = RegInfo.createVirtualRegister(RC);
BuildMI(MBB, II, DL, get(Mips::LwConstant32), Reg).addImm(Imm);
NewImm = 0;
return Reg;
}
unsigned Mips16InstrInfo::getAnalyzableBrOpc(unsigned Opc) const {
return (Opc == Mips::BeqzRxImmX16 || Opc == Mips::BimmX16 ||
Opc == Mips::Bimm16 ||
Opc == Mips::Bteqz16 || Opc == Mips::Btnez16 ||
Opc == Mips::BeqzRxImm16 || Opc == Mips::BnezRxImm16 ||
Opc == Mips::BnezRxImmX16 || Opc == Mips::BteqzX16 ||
Opc == Mips::BteqzT8CmpX16 || Opc == Mips::BteqzT8CmpiX16 ||
Opc == Mips::BteqzT8SltX16 || Opc == Mips::BteqzT8SltuX16 ||
Opc == Mips::BteqzT8SltiX16 || Opc == Mips::BteqzT8SltiuX16 ||
Opc == Mips::BtnezX16 || Opc == Mips::BtnezT8CmpX16 ||
Opc == Mips::BtnezT8CmpiX16 || Opc == Mips::BtnezT8SltX16 ||
Opc == Mips::BtnezT8SltuX16 || Opc == Mips::BtnezT8SltiX16 ||
Opc == Mips::BtnezT8SltiuX16 ) ? Opc : 0;
}
void Mips16InstrInfo::ExpandRetRA16(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
unsigned Opc) const {
BuildMI(MBB, I, I->getDebugLoc(), get(Opc));
}
const MCInstrDesc &Mips16InstrInfo::AddiuSpImm(int64_t Imm) const {
if (validSpImm8(Imm))
return get(Mips::AddiuSpImm16);
else
return get(Mips::AddiuSpImmX16);
}
void Mips16InstrInfo::BuildAddiuSpImm
(MachineBasicBlock &MBB, MachineBasicBlock::iterator I, int64_t Imm) const {
DebugLoc DL = I != MBB.end() ? I->getDebugLoc() : DebugLoc();
BuildMI(MBB, I, DL, AddiuSpImm(Imm)).addImm(Imm);
}
const MipsInstrInfo *llvm::createMips16InstrInfo(MipsTargetMachine &TM) {
return new Mips16InstrInfo(TM);
}
bool Mips16InstrInfo::validImmediate(unsigned Opcode, unsigned Reg,
int64_t Amount) {
switch (Opcode) {
case Mips::LbRxRyOffMemX16:
case Mips::LbuRxRyOffMemX16:
case Mips::LhRxRyOffMemX16:
case Mips::LhuRxRyOffMemX16:
case Mips::SbRxRyOffMemX16:
case Mips::ShRxRyOffMemX16:
case Mips::LwRxRyOffMemX16:
case Mips::SwRxRyOffMemX16:
case Mips::SwRxSpImmX16:
case Mips::LwRxSpImmX16:
return isInt<16>(Amount);
case Mips::AddiuRxRyOffMemX16:
if ((Reg == Mips::PC) || (Reg == Mips::SP))
return isInt<16>(Amount);
return isInt<15>(Amount);
}
llvm_unreachable("unexpected Opcode in validImmediate");
}
/// Measure the specified inline asm to determine an approximation of its
/// length.
/// Comments (which run till the next SeparatorString or newline) do not
/// count as an instruction.
/// Any other non-whitespace text is considered an instruction, with
/// multiple instructions separated by SeparatorString or newlines.
/// Variable-length instructions are not handled here; this function
/// may be overloaded in the target code to do that.
/// We implement the special case of the .space directive taking only an
/// integer argument, which is the size in bytes. This is used for creating
/// inline code spacing for testing purposes using inline assembly.
///
unsigned Mips16InstrInfo::getInlineAsmLength(const char *Str,
const MCAsmInfo &MAI) const {
// Count the number of instructions in the asm.
bool atInsnStart = true;
unsigned Length = 0;
for (; *Str; ++Str) {
if (*Str == '\n' || strncmp(Str, MAI.getSeparatorString(),
strlen(MAI.getSeparatorString())) == 0)
atInsnStart = true;
if (atInsnStart && !std::isspace(static_cast<unsigned char>(*Str))) {
if (strncmp(Str, ".space", 6)==0) {
char *EStr; int Sz;
Sz = strtol(Str+6, &EStr, 10);
while (isspace(*EStr)) ++EStr;
if (*EStr=='\0') {
DEBUG(dbgs() << "parsed .space " << Sz << '\n');
return Sz;
}
}
Length += MAI.getMaxInstLength();
atInsnStart = false;
}
if (atInsnStart && strncmp(Str, MAI.getCommentString(),
strlen(MAI.getCommentString())) == 0)
atInsnStart = false;
}
return Length;
}
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