-// Insert instructions to initialize the global base register in the
-// first MBB of the function. When the ABI is O32 and the relocation model is
-// PIC, the necessary instructions are emitted later to prevent optimization
-// passes from moving them.
-void MipsDAGToDAGISel::InitGlobalBaseReg(MachineFunction &MF) {
- MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
-
- if (((MF.getTarget().getRelocationModel() == Reloc::Static) ||
- Subtarget.inMips16Mode()) && !MipsFI->globalBaseRegSet())
- return;
-
- MachineBasicBlock &MBB = MF.front();
- MachineBasicBlock::iterator I = MBB.begin();
- MachineRegisterInfo &RegInfo = MF.getRegInfo();
- const MipsRegisterInfo *TargetRegInfo = TM.getRegisterInfo();
- const MipsInstrInfo *MII = TM.getInstrInfo();
- const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
- DebugLoc DL = I != MBB.end() ? I->getDebugLoc() : DebugLoc();
- unsigned V0, V1, GlobalBaseReg = MipsFI->getGlobalBaseReg();
- int FI; // should initialize this to some kind of null
-
- if (!Subtarget.inMips16Mode())
- FI= MipsFI->initGlobalRegFI();
-
- const TargetRegisterClass *RC = Subtarget.isABI_N64() ?
- (const TargetRegisterClass*)&Mips::CPU64RegsRegClass :
- (const TargetRegisterClass*)&Mips::CPURegsRegClass;
-
- V0 = RegInfo.createVirtualRegister(RC);
- V1 = RegInfo.createVirtualRegister(RC);
-
- if (Subtarget.isABI_N64()) {
- MF.getRegInfo().addLiveIn(Mips::T9_64);
- MBB.addLiveIn(Mips::T9_64);
-
- // lui $v0, %hi(%neg(%gp_rel(fname)))
- // daddu $v1, $v0, $t9
- // daddiu $globalbasereg, $v1, %lo(%neg(%gp_rel(fname)))
- const GlobalValue *FName = MF.getFunction();
- BuildMI(MBB, I, DL, TII.get(Mips::LUi64), V0)
- .addGlobalAddress(FName, 0, MipsII::MO_GPOFF_HI);
- BuildMI(MBB, I, DL, TII.get(Mips::DADDu), V1).addReg(V0)
- .addReg(Mips::T9_64);
- BuildMI(MBB, I, DL, TII.get(Mips::DADDiu), GlobalBaseReg).addReg(V1)
- .addGlobalAddress(FName, 0, MipsII::MO_GPOFF_LO);
- MII->storeRegToStackSlot(MBB, I, GlobalBaseReg, false, FI, RC,
- TargetRegInfo);
- return;
- }
-
- if (MF.getTarget().getRelocationModel() == Reloc::Static) {
- // Set global register to __gnu_local_gp.
- //
- // lui $v0, %hi(__gnu_local_gp)
- // addiu $globalbasereg, $v0, %lo(__gnu_local_gp)
- BuildMI(MBB, I, DL, TII.get(Mips::LUi), V0)
- .addExternalSymbol("__gnu_local_gp", MipsII::MO_ABS_HI);
- BuildMI(MBB, I, DL, TII.get(Mips::ADDiu), GlobalBaseReg).addReg(V0)
- .addExternalSymbol("__gnu_local_gp", MipsII::MO_ABS_LO);
- MII->storeRegToStackSlot(MBB, I, GlobalBaseReg, false, FI, RC,
- TargetRegInfo);
- return;
- }
-
- MF.getRegInfo().addLiveIn(Mips::T9);
- MBB.addLiveIn(Mips::T9);
-
- if (Subtarget.isABI_N32()) {
- // lui $v0, %hi(%neg(%gp_rel(fname)))
- // addu $v1, $v0, $t9
- // addiu $globalbasereg, $v1, %lo(%neg(%gp_rel(fname)))
- const GlobalValue *FName = MF.getFunction();
- BuildMI(MBB, I, DL, TII.get(Mips::LUi), V0)
- .addGlobalAddress(FName, 0, MipsII::MO_GPOFF_HI);
- BuildMI(MBB, I, DL, TII.get(Mips::ADDu), V1).addReg(V0).addReg(Mips::T9);
- BuildMI(MBB, I, DL, TII.get(Mips::ADDiu), GlobalBaseReg).addReg(V1)
- .addGlobalAddress(FName, 0, MipsII::MO_GPOFF_LO);
- MII->storeRegToStackSlot(MBB, I, GlobalBaseReg, false, FI, RC,
- TargetRegInfo);
- return;
- }
-
- assert(Subtarget.isABI_O32());
-
- if (Subtarget.inMips16Mode())
- return; // no need to load GP. It can be calculated anywhere
-
-
- // For O32 ABI, the following instruction sequence is emitted to initialize
- // the global base register:
- //
- // 0. lui $2, %hi(_gp_disp)
- // 1. addiu $2, $2, %lo(_gp_disp)
- // 2. addu $globalbasereg, $2, $t9
- //
- // We emit only the last instruction here.
- //
- // GNU linker requires that the first two instructions appear at the beginning
- // of a function and no instructions be inserted before or between them.
- // The two instructions are emitted during lowering to MC layer in order to
- // avoid any reordering.
- //
- // Register $2 (Mips::V0) is added to the list of live-in registers to ensure
- // the value instruction 1 (addiu) defines is valid when instruction 2 (addu)
- // reads it.
- MF.getRegInfo().addLiveIn(Mips::V0);
- MBB.addLiveIn(Mips::V0);
- BuildMI(MBB, I, DL, TII.get(Mips::ADDu), GlobalBaseReg)
- .addReg(Mips::V0).addReg(Mips::T9);
- MII->storeRegToStackSlot(MBB, I, GlobalBaseReg, false, FI, RC, TargetRegInfo);