+ const GlobalValue *GV =
+ cast<GlobalValue>((*MI->memoperands_begin())->getValue());
+
+ if (!Subtarget.GVIsIndirectSymbol(GV, RM)) {
+ expandLoadStackGuardBase(MI, ARM::MOV_ga_pcrel, ARM::LDRi12, RM);
+ return;
+ }
+
+ MachineBasicBlock &MBB = *MI->getParent();
+ DebugLoc DL = MI->getDebugLoc();
+ unsigned Reg = MI->getOperand(0).getReg();
+ MachineInstrBuilder MIB;
+
+ MIB = BuildMI(MBB, MI, DL, get(ARM::MOV_ga_pcrel_ldr), Reg)
+ .addGlobalAddress(GV, 0, ARMII::MO_NONLAZY);
+ unsigned Flag = MachineMemOperand::MOLoad | MachineMemOperand::MOInvariant;
+ MachineMemOperand *MMO = MBB.getParent()->getMachineMemOperand(
+ MachinePointerInfo::getGOT(*MBB.getParent()), Flag, 4, 4);
+ MIB.addMemOperand(MMO);
+ MIB = BuildMI(MBB, MI, DL, get(ARM::LDRi12), Reg);
+ MIB.addReg(Reg, RegState::Kill).addImm(0);
+ MIB.setMemRefs(MI->memoperands_begin(), MI->memoperands_end());
+ AddDefaultPred(MIB);
+}
+
+namespace {
+ /// ARMCGBR - Create Global Base Reg pass. This initializes the PIC
+ /// global base register for ARM ELF.
+ struct ARMCGBR : public MachineFunctionPass {
+ static char ID;
+ ARMCGBR() : MachineFunctionPass(ID) {}
+
+ bool runOnMachineFunction(MachineFunction &MF) override {
+ ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
+ if (AFI->getGlobalBaseReg() == 0)
+ return false;
+ const ARMSubtarget &STI =
+ static_cast<const ARMSubtarget &>(MF.getSubtarget());
+ // Don't do this for Thumb1.
+ if (STI.isThumb1Only())
+ return false;
+
+ const TargetMachine &TM = MF.getTarget();
+ if (TM.getRelocationModel() != Reloc::PIC_)
+ return false;
+
+ LLVMContext *Context = &MF.getFunction()->getContext();
+ unsigned ARMPCLabelIndex = AFI->createPICLabelUId();
+ unsigned PCAdj = STI.isThumb() ? 4 : 8;
+ ARMConstantPoolValue *CPV = ARMConstantPoolSymbol::Create(
+ *Context, "_GLOBAL_OFFSET_TABLE_", ARMPCLabelIndex, PCAdj);
+
+ unsigned Align = MF.getDataLayout().getPrefTypeAlignment(
+ Type::getInt32PtrTy(*Context));
+ unsigned Idx = MF.getConstantPool()->getConstantPoolIndex(CPV, Align);
+
+ MachineBasicBlock &FirstMBB = MF.front();
+ MachineBasicBlock::iterator MBBI = FirstMBB.begin();
+ DebugLoc DL = FirstMBB.findDebugLoc(MBBI);
+ unsigned TempReg =
+ MF.getRegInfo().createVirtualRegister(&ARM::rGPRRegClass);
+ unsigned Opc = STI.isThumb2() ? ARM::t2LDRpci : ARM::LDRcp;
+ const TargetInstrInfo &TII = *STI.getInstrInfo();
+ MachineInstrBuilder MIB = BuildMI(FirstMBB, MBBI, DL,
+ TII.get(Opc), TempReg)
+ .addConstantPoolIndex(Idx);
+ if (Opc == ARM::LDRcp)
+ MIB.addImm(0);
+ AddDefaultPred(MIB);
+
+ // Fix the GOT address by adding pc.
+ unsigned GlobalBaseReg = AFI->getGlobalBaseReg();
+ Opc = STI.isThumb2() ? ARM::tPICADD : ARM::PICADD;
+ MIB = BuildMI(FirstMBB, MBBI, DL, TII.get(Opc), GlobalBaseReg)
+ .addReg(TempReg)
+ .addImm(ARMPCLabelIndex);
+ if (Opc == ARM::PICADD)
+ AddDefaultPred(MIB);
+
+ return true;
+ }
+
+ const char *getPassName() const override {
+ return "ARM PIC Global Base Reg Initialization";
+ }
+
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
+ AU.setPreservesCFG();
+ MachineFunctionPass::getAnalysisUsage(AU);
+ }
+ };