1 //===-- DelaySlotFiller.cpp - Mips delay slot filler ---------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file was developed by Bruno Cardoso Lopes and is distributed under 6 // the University of Illinois Open Source License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // Simple pass to fills delay slots with NOPs. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #define DEBUG_TYPE "delay-slot-filler" 15 16 #include "Mips.h" 17 #include "MipsTargetMachine.h" 18 #include "llvm/CodeGen/MachineFunctionPass.h" 19 #include "llvm/CodeGen/MachineInstrBuilder.h" 20 #include "llvm/Target/TargetInstrInfo.h" 21 #include "llvm/ADT/Statistic.h" 22 23 using namespace llvm; 24 25 STATISTIC(FilledSlots, "Number of delay slots filled"); 26 27 namespace { 28 struct Filler : public MachineFunctionPass { 29 30 TargetMachine &TM; 31 const TargetInstrInfo *TII; 32 33 static char ID; 34 Filler(TargetMachine &tm) 35 : MachineFunctionPass((intptr_t)&ID), TM(tm), TII(tm.getInstrInfo()) { } 36 37 virtual const char *getPassName() const { 38 return "Mips Delay Slot Filler"; 39 } 40 41 bool runOnMachineBasicBlock(MachineBasicBlock &MBB); 42 bool runOnMachineFunction(MachineFunction &F) { 43 bool Changed = false; 44 for (MachineFunction::iterator FI = F.begin(), FE = F.end(); 45 FI != FE; ++FI) 46 Changed |= runOnMachineBasicBlock(*FI); 47 return Changed; 48 } 49 50 }; 51 char Filler::ID = 0; 52 } // end of anonymous namespace 53 54 /// runOnMachineBasicBlock - Fill in delay slots for the given basic block. 55 /// Currently, we fill delay slots with NOPs. We assume there is only one 56 /// delay slot per delayed instruction. 57 bool Filler:: 58 runOnMachineBasicBlock(MachineBasicBlock &MBB) 59 { 60 bool Changed = false; 61 for (MachineBasicBlock::iterator I = MBB.begin(); I != MBB.end(); ++I) 62 if (TII->hasDelaySlot(I->getOpcode())) { 63 MachineBasicBlock::iterator J = I; 64 ++J; 65 BuildMI(MBB, J, TII->get(Mips::NOP)); 66 ++FilledSlots; 67 Changed = true; 68 } 69 return Changed; 70 } 71 72 /// createMipsDelaySlotFillerPass - Returns a pass that fills in delay 73 /// slots in Mips MachineFunctions 74 FunctionPass *llvm::createMipsDelaySlotFillerPass(MipsTargetMachine &tm) { 75 return new Filler(tm); 76 } 77 78