void splitMBB(MachineBasicBlock *MBB);
void initMBBInfo();
int64_t computeOffset(const MachineInstr *Br);
- bool offsetFitsIntoField(const MachineInstr *Br);
- unsigned addLongBranch(MachineBasicBlock &MBB, Iter Pos,
- MachineBasicBlock *Tgt, DebugLoc DL, bool Nop);
void replaceBranch(MachineBasicBlock &MBB, Iter Br, DebugLoc DL,
MachineBasicBlock *MBBOpnd);
void expandToLongBranch(MBBInfo &Info);
ReverseIter Br = getNonDebugInstr(MBB->rbegin(), End);
if ((Br != End) && !Br->isIndirectBranch() &&
- (Br->isConditionalBranch() || Br->isUnconditionalBranch()))
+ (Br->isConditionalBranch() ||
+ (Br->isUnconditionalBranch() &&
+ TM.getRelocationModel() == Reloc::PIC_)))
MBBInfos[I].Br = (++Br).base();
}
}
return -Offset + 4;
}
-// Insert the following sequence:
-// (pic or N64)
-// lw $at, global_reg_slot
-// lw $at, got($L1)($at)
-// addiu $at, $at, lo($L1)
-// jr $at
-// noop
-// (static and !N64)
-// lui $at, hi($L1)
-// addiu $at, $at, lo($L1)
-// jr $at
-// noop
-unsigned MipsLongBranch::addLongBranch(MachineBasicBlock &MBB, Iter Pos,
- MachineBasicBlock *Tgt, DebugLoc DL,
- bool Nop) {
- MF->getInfo<MipsFunctionInfo>()->setEmitNOAT();
- bool IsPIC = (TM.getRelocationModel() == Reloc::PIC_);
- unsigned ABI = TM.getSubtarget<MipsSubtarget>().getTargetABI();
- bool N64 = (ABI == MipsSubtarget::N64);
- unsigned NumInstrs;
-
- if (IsPIC || N64) {
- bool HasMips64 = TM.getSubtarget<MipsSubtarget>().hasMips64();
- unsigned AT = N64 ? Mips::AT_64 : Mips::AT;
- unsigned Load = N64 ? Mips::LD_P8 : Mips::LW;
- unsigned ADDiu = N64 ? Mips::DADDiu : Mips::ADDiu;
- unsigned JR = N64 ? Mips::JR64 : Mips::JR;
- unsigned GOTFlag = HasMips64 ? MipsII::MO_GOT_PAGE : MipsII::MO_GOT;
- unsigned OFSTFlag = HasMips64 ? MipsII::MO_GOT_OFST : MipsII::MO_ABS_LO;
- const MipsRegisterInfo *MRI =
- static_cast<const MipsRegisterInfo*>(TM.getRegisterInfo());
- unsigned SP = MRI->getFrameRegister(*MF);
- unsigned GlobalRegFI = MF->getInfo<MipsFunctionInfo>()->getGlobalRegFI();
- int64_t Offset = MF->getFrameInfo()->getObjectOffset(GlobalRegFI);
-
- if (isInt<16>(Offset)) {
- BuildMI(MBB, Pos, DL, TII->get(Load), AT).addReg(SP).addImm(Offset);
- NumInstrs = 1;
- } else {
- unsigned ADDu = N64 ? Mips::DADDu : Mips::ADDu;
- MipsAnalyzeImmediate::Inst LastInst(0, 0);
-
- MF->getInfo<MipsFunctionInfo>()->setEmitNOAT();
- NumInstrs = Mips::loadImmediate(Offset, N64, *TII, MBB, Pos, DL, true,
- &LastInst) + 2;
- BuildMI(MBB, Pos, DL, TII->get(ADDu), AT).addReg(SP).addReg(AT);
- BuildMI(MBB, Pos, DL, TII->get(Load), AT).addReg(AT)
- .addImm(SignExtend64<16>(LastInst.ImmOpnd));
- }
-
- BuildMI(MBB, Pos, DL, TII->get(Load), AT).addReg(AT).addMBB(Tgt, GOTFlag);
- BuildMI(MBB, Pos, DL, TII->get(ADDiu), AT).addReg(AT).addMBB(Tgt, OFSTFlag);
- BuildMI(MBB, Pos, DL, TII->get(JR)).addReg(Mips::AT, RegState::Kill);
- NumInstrs += 3;
- } else {
- BuildMI(MBB, Pos, DL, TII->get(Mips::LUi), Mips::AT)
- .addMBB(Tgt, MipsII::MO_ABS_HI);
- BuildMI(MBB, Pos, DL, TII->get(Mips::ADDiu), Mips::AT)
- .addReg(Mips::AT).addMBB(Tgt, MipsII::MO_ABS_LO);
- BuildMI(MBB, Pos, DL, TII->get(Mips::JR)).addReg(Mips::AT, RegState::Kill);
- NumInstrs = 3;
- }
-
- if (Nop) {
- BuildMI(MBB, Pos, DL, TII->get(Mips::NOP))->setIsInsideBundle();
- ++NumInstrs;
- }
-
- return NumInstrs;
-}
-
// Replace Br with a branch which has the opposite condition code and a
// MachineBasicBlock operand MBBOpnd.
void MipsLongBranch::replaceBranch(MachineBasicBlock &MBB, Iter Br,
void MipsLongBranch::expandToLongBranch(MBBInfo &I) {
I.HasLongBranch = true;
- MachineBasicBlock *MBB = I.Br->getParent(), *Tgt = getTargetMBB(*I.Br);
+ bool IsPIC = TM.getRelocationModel() == Reloc::PIC_;
+ unsigned ABI = TM.getSubtarget<MipsSubtarget>().getTargetABI();
+ bool N64 = ABI == MipsSubtarget::N64;
+
+ MachineBasicBlock::iterator Pos;
+ MachineBasicBlock *MBB = I.Br->getParent(), *TgtMBB = getTargetMBB(*I.Br);
DebugLoc DL = I.Br->getDebugLoc();
+ const BasicBlock *BB = MBB->getBasicBlock();
+ MachineFunction::iterator FallThroughMBB = ++MachineFunction::iterator(MBB);
+ MachineBasicBlock *LongBrMBB = MF->CreateMachineBasicBlock(BB);
+
+ MF->insert(FallThroughMBB, LongBrMBB);
+ MBB->removeSuccessor(TgtMBB);
+ MBB->addSuccessor(LongBrMBB);
+
+ if (IsPIC) {
+ // $longbr:
+ // addiu $sp, $sp, -regsize * 2
+ // sw $ra, 0($sp)
+ // bal $baltgt
+ // sw $a3, regsize($sp)
+ // $baltgt:
+ // lui $a3, %hi($baltgt)
+ // lui $at, %hi($tgt)
+ // addiu $a3, $a3, %lo($baltgt)
+ // addiu $at, $at, %lo($tgt)
+ // subu $at, $at, $a3
+ // addu $at, $ra, $at
+ //
+ // if n64:
+ // lui $a3, %highest($baltgt)
+ // lui $ra, %highest($tgt)
+ // addiu $a3, $a3, %higher($baltgt)
+ // addiu $ra, $ra, %higher($tgt)
+ // dsll $a3, $a3, 32
+ // dsll $ra, $ra, 32
+ // subu $at, $at, $a3
+ // addu $at, $at, $ra
+ //
+ // lw $ra, 0($sp)
+ // lw $a3, regsize($sp)
+ // jr $at
+ // addiu $sp, $sp, regsize * 2
+ // $fallthrough:
+ //
+ MF->getInfo<MipsFunctionInfo>()->setEmitNOAT();
+ MachineBasicBlock *BalTgtMBB = MF->CreateMachineBasicBlock(BB);
+ MF->insert(FallThroughMBB, BalTgtMBB);
+ LongBrMBB->addSuccessor(BalTgtMBB);
+ BalTgtMBB->addSuccessor(TgtMBB);
- if (I.Br->isUnconditionalBranch()) {
- // Unconditional branch before transformation:
- // b $tgt
- // delay-slot-instr
+ int RegSize = N64 ? 8 : 4;
+ unsigned AT = N64 ? Mips::AT_64 : Mips::AT;
+ unsigned A3 = N64 ? Mips::A3_64 : Mips::A3;
+ unsigned SP = N64 ? Mips::SP_64 : Mips::SP;
+ unsigned RA = N64 ? Mips::RA_64 : Mips::RA;
+ unsigned Load = N64 ? Mips::LD_P8 : Mips::LW;
+ unsigned Store = N64 ? Mips::SD_P8 : Mips::SW;
+ unsigned LUi = N64 ? Mips::LUi64 : Mips::LUi;
+ unsigned ADDiu = N64 ? Mips::DADDiu : Mips::ADDiu;
+ unsigned ADDu = N64 ? Mips::DADDu : Mips::ADDu;
+ unsigned SUBu = N64 ? Mips::SUBu : Mips::SUBu;
+ unsigned JR = N64 ? Mips::JR64 : Mips::JR;
+
+ Pos = LongBrMBB->begin();
+
+ BuildMI(*LongBrMBB, Pos, DL, TII->get(ADDiu), SP).addReg(SP)
+ .addImm(-RegSize * 2);
+ BuildMI(*LongBrMBB, Pos, DL, TII->get(Store)).addReg(RA).addReg(SP)
+ .addImm(0);
+ BuildMI(*LongBrMBB, Pos, DL, TII->get(Mips::BAL_BR)).addMBB(BalTgtMBB);
+ BuildMI(*LongBrMBB, Pos, DL, TII->get(Store)).addReg(A3).addReg(SP)
+ .addImm(RegSize)->setIsInsideBundle();
+
+ Pos = BalTgtMBB->begin();
+
+ BuildMI(*BalTgtMBB, Pos, DL, TII->get(LUi), A3)
+ .addMBB(BalTgtMBB, MipsII::MO_ABS_HI);
+ BuildMI(*BalTgtMBB, Pos, DL, TII->get(LUi), AT)
+ .addMBB(TgtMBB, MipsII::MO_ABS_HI);
+ BuildMI(*BalTgtMBB, Pos, DL, TII->get(ADDiu), A3).addReg(A3)
+ .addMBB(BalTgtMBB, MipsII::MO_ABS_LO);
+ BuildMI(*BalTgtMBB, Pos, DL, TII->get(ADDiu), AT).addReg(AT)
+ .addMBB(TgtMBB, MipsII::MO_ABS_LO);
+ BuildMI(*BalTgtMBB, Pos, DL, TII->get(SUBu), AT).addReg(AT).addReg(A3);
+ BuildMI(*BalTgtMBB, Pos, DL, TII->get(ADDu), AT).addReg(RA).addReg(AT);
+
+ if (N64) {
+ BuildMI(*BalTgtMBB, Pos, DL, TII->get(LUi), A3)
+ .addMBB(BalTgtMBB, MipsII::MO_HIGHEST);
+ BuildMI(*BalTgtMBB, Pos, DL, TII->get(LUi), RA)
+ .addMBB(TgtMBB, MipsII::MO_HIGHEST);
+ BuildMI(*BalTgtMBB, Pos, DL, TII->get(ADDiu), A3).addReg(A3)
+ .addMBB(BalTgtMBB, MipsII::MO_HIGHER);
+ BuildMI(*BalTgtMBB, Pos, DL, TII->get(ADDiu), RA).addReg(RA)
+ .addMBB(TgtMBB, MipsII::MO_HIGHER);
+ BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::DSLL), A3).addReg(A3)
+ .addImm(32);
+ BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::DSLL), RA).addReg(RA)
+ .addImm(32);
+ BuildMI(*BalTgtMBB, Pos, DL, TII->get(SUBu), AT).addReg(AT).addReg(A3);
+ BuildMI(*BalTgtMBB, Pos, DL, TII->get(ADDu), AT).addReg(AT).addReg(RA);
+ I.Size += 4 * 8;
+ }
+
+ BuildMI(*BalTgtMBB, Pos, DL, TII->get(Load), RA).addReg(SP).addImm(0);
+ BuildMI(*BalTgtMBB, Pos, DL, TII->get(Load), A3).addReg(SP).addImm(RegSize);
+ BuildMI(*BalTgtMBB, Pos, DL, TII->get(JR)).addReg(AT);
+ BuildMI(*BalTgtMBB, Pos, DL, TII->get(ADDiu), SP).addReg(SP)
+ .addImm(RegSize * 2)->setIsInsideBundle();
+ I.Size += 4 * 14;
+ } else {
+ // $longbr:
+ // j $tgt
+ // nop
+ // $fallthrough:
//
- // after transformation:
- // delay-slot-instr
- // lw $at, global_reg_slot
- // lw $at, %got($tgt)($at)
- // addiu $at, $at, %lo($tgt)
- // jr $at
- // nop
- I.Size += (addLongBranch(*MBB, llvm::next(Iter(I.Br)), Tgt, DL, true)
- - 1) * 4;
-
- // Remove branch and clear InsideBundle bit of the next instruction.
- llvm::next(MachineBasicBlock::instr_iterator(I.Br))
- ->setIsInsideBundle(false);
- I.Br->eraseFromParent();
- return;
+ Pos = LongBrMBB->begin();
+ LongBrMBB->addSuccessor(TgtMBB);
+ BuildMI(*LongBrMBB, Pos, DL, TII->get(Mips::J)).addMBB(TgtMBB);
+ BuildMI(*LongBrMBB, Pos, DL, TII->get(Mips::NOP))->setIsInsideBundle();
+ I.Size += 4 * 2;
}
- assert(I.Br->isConditionalBranch() && "Conditional branch expected.");
-
- // Conditional branch before transformation:
- // b cc, $tgt
- // delay-slot-instr
- // FallThrough:
- //
- // after transformation:
- // b !cc, FallThrough
- // delay-slot-instr
- // NewMBB:
- // lw $at, global_reg_slot
- // lw $at, %got($tgt)($at)
- // addiu $at, $at, %lo($tgt)
- // jr $at
- // noop
- // FallThrough:
-
- MachineBasicBlock *NewMBB = MF->CreateMachineBasicBlock(MBB->getBasicBlock());
- MF->insert(llvm::next(MachineFunction::iterator(MBB)), NewMBB);
- MBB->removeSuccessor(Tgt);
- MBB->addSuccessor(NewMBB);
- NewMBB->addSuccessor(Tgt);
-
- I.Size += addLongBranch(*NewMBB, NewMBB->begin(), Tgt, DL, true) * 4;
- replaceBranch(*MBB, I.Br, DL, *MBB->succ_begin());
+ if (I.Br->isUnconditionalBranch()) {
+ // Change branch destination.
+ assert(I.Br->getDesc().getNumOperands() == 1);
+ I.Br->RemoveOperand(0);
+ I.Br->addOperand(MachineOperand::CreateMBB(LongBrMBB));
+ } else
+ // Change branch destination and reverse condition.
+ replaceBranch(*MBB, I.Br, DL, FallThroughMBB);
}
static void emitGPDisp(MachineFunction &F, const MipsInstrInfo *TII) {
MF = &F;
initMBBInfo();
- bool IsPIC = (TM.getRelocationModel() == Reloc::PIC_);
SmallVector<MBBInfo, 16>::iterator I, E = MBBInfos.end();
bool EverMadeChange = false, MadeChange = true;
if (!I->Br || I->HasLongBranch)
continue;
- if (!ForceLongBranch) {
- int64_t Offset = computeOffset(I->Br);
-
+ if (!ForceLongBranch)
// Check if offset fits into 16-bit immediate field of branches.
- if ((I->Br->isConditionalBranch() || IsPIC) && isInt<16>(Offset / 4))
- continue;
-
- // Check if offset fits into 26-bit immediate field of jumps (J).
- if (I->Br->isUnconditionalBranch() && !IsPIC && isInt<26>(Offset / 4))
+ if (isInt<16>(computeOffset(I->Br) / 4))
continue;
- }
expandToLongBranch(*I);
++LongBranches;