llvm-6502/lib/Target/Mips/MipsDelaySlotFiller.cpp
2007-08-18 01:50:47 +00:00

78 lines
2.3 KiB
C++

//===-- DelaySlotFiller.cpp - Mips delay slot filler ---------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Bruno Cardoso Lopes and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Simple pass to fills delay slots with NOPs.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "delay-slot-filler"
#include "Mips.h"
#include "MipsTargetMachine.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/ADT/Statistic.h"
using namespace llvm;
STATISTIC(FilledSlots, "Number of delay slots filled");
namespace {
struct Filler : public MachineFunctionPass {
TargetMachine &TM;
const TargetInstrInfo *TII;
static char ID;
Filler(TargetMachine &tm)
: MachineFunctionPass((intptr_t)&ID), TM(tm), TII(tm.getInstrInfo()) { }
virtual const char *getPassName() const {
return "Mips Delay Slot Filler";
}
bool runOnMachineBasicBlock(MachineBasicBlock &MBB);
bool runOnMachineFunction(MachineFunction &F) {
bool Changed = false;
for (MachineFunction::iterator FI = F.begin(), FE = F.end();
FI != FE; ++FI)
Changed |= runOnMachineBasicBlock(*FI);
return Changed;
}
};
char Filler::ID = 0;
} // end of anonymous namespace
/// runOnMachineBasicBlock - Fill in delay slots for the given basic block.
/// Currently, we fill delay slots with NOPs. We assume there is only one
/// delay slot per delayed instruction.
bool Filler::
runOnMachineBasicBlock(MachineBasicBlock &MBB)
{
bool Changed = false;
for (MachineBasicBlock::iterator I = MBB.begin(); I != MBB.end(); ++I)
if (TII->hasDelaySlot(I->getOpcode())) {
MachineBasicBlock::iterator J = I;
++J;
BuildMI(MBB, J, TII->get(Mips::NOP));
++FilledSlots;
Changed = true;
}
return Changed;
}
/// createMipsDelaySlotFillerPass - Returns a pass that fills in delay
/// slots in Mips MachineFunctions
FunctionPass *llvm::createMipsDelaySlotFillerPass(MipsTargetMachine &tm) {
return new Filler(tm);
}