1 //===-- MipsEmitGPRestore.cpp - Emit GP restore instruction-----------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===-----------------------------------------------------------------------===//
10 // This pass emits instructions that restore $gp right
11 // after jalr instructions.
13 //===-----------------------------------------------------------------------===//
15 #define DEBUG_TYPE "emit-gp-restore"
18 #include "MipsTargetMachine.h"
19 #include "MipsMachineFunction.h"
20 #include "llvm/CodeGen/MachineFunctionPass.h"
21 #include "llvm/CodeGen/MachineInstrBuilder.h"
22 #include "llvm/Target/TargetInstrInfo.h"
23 #include "llvm/ADT/Statistic.h"
28 struct Inserter : public MachineFunctionPass {
31 const TargetInstrInfo *TII;
34 Inserter(TargetMachine &tm)
35 : MachineFunctionPass(ID), TM(tm), TII(tm.getInstrInfo()) { }
37 virtual const char *getPassName() const {
38 return "Mips Emit GP Restore";
41 bool runOnMachineBasicBlock(MachineBasicBlock &MBB);
42 bool runOnMachineFunction(MachineFunction &F);
44 char Inserter::ID = 0;
45 } // end of anonymous namespace
47 bool Inserter::runOnMachineFunction(MachineFunction &F) {
48 if (TM.getRelocationModel() != Reloc::PIC_)
52 int FI = F.getInfo<MipsFunctionInfo>()->getGPFI();
54 for (MachineFunction::iterator MFI = F.begin(), MFE = F.end();
56 MachineBasicBlock& MBB = *MFI;
57 MachineBasicBlock::iterator I = MFI->begin();
59 while (I != MFI->end()) {
60 if (I->getOpcode() != Mips::JALR) {
65 DebugLoc dl = I->getDebugLoc();
66 // emit lw $gp, ($gp save slot on stack) after jalr
67 BuildMI(MBB, ++I, dl, TII->get(Mips::LW), Mips::GP).addImm(0).addFrameIndex(FI);
75 /// createMipsEmitGPRestorePass - Returns a pass that emits instructions that
76 /// restores $gp clobbered by jalr instructions.
77 FunctionPass *llvm::createMipsEmitGPRestorePass(MipsTargetMachine &tm) {
78 return new Inserter(tm);