llvm-6502/lib/Target/Sparc/DelaySlotFiller.cpp

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//===-- DelaySlotFiller.cpp - SPARC delay slot filler ---------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This is a simple local pass that fills delay slots with NOPs.
//
//===----------------------------------------------------------------------===//
#include "Sparc.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/ADT/Statistic.h"
using namespace llvm;
namespace {
Statistic<> FilledSlots("delayslotfiller", "Num. of delay slots filled");
struct Filler : public MachineFunctionPass {
/// Target machine description which we query for reg. names, data
/// layout, etc.
///
TargetMachine &TM;
const TargetInstrInfo *TII;
Filler(TargetMachine &tm) : TM(tm), TII(tm.getInstrInfo()) { }
virtual const char *getPassName() const {
return "SPARC 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;
}
};
} // end of anonymous namespace
/// createSparcDelaySlotFillerPass - Returns a pass that fills in delay
/// slots in Sparc MachineFunctions
///
FunctionPass *llvm::createSparcDelaySlotFillerPass(TargetMachine &tm) {
return new Filler(tm);
}
/// 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, SP::NOP, 0);
++FilledSlots;
Changed = true;
}
return Changed;
}