forked from OSchip/llvm-project
83 lines
2.4 KiB
C++
83 lines
2.4 KiB
C++
//===-- DelaySlotFiller.cpp - Mips delay slot filler ---------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// Simple pass to fills delay slots with NOPs.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "delay-slot-filler"
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#include "Mips.h"
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#include "MipsTargetMachine.h"
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#include "llvm/CodeGen/MachineFunctionPass.h"
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#include "llvm/CodeGen/MachineInstrBuilder.h"
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#include "llvm/Target/TargetInstrInfo.h"
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#include "llvm/ADT/Statistic.h"
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using namespace llvm;
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STATISTIC(FilledSlots, "Number of delay slots filled");
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namespace {
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struct Filler : public MachineFunctionPass {
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TargetMachine &TM;
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const TargetInstrInfo *TII;
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static char ID;
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Filler(TargetMachine &tm)
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: MachineFunctionPass(ID), TM(tm), TII(tm.getInstrInfo()) { }
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virtual const char *getPassName() const {
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return "Mips Delay Slot Filler";
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}
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bool runOnMachineBasicBlock(MachineBasicBlock &MBB);
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bool runOnMachineFunction(MachineFunction &F) {
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bool Changed = false;
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for (MachineFunction::iterator FI = F.begin(), FE = F.end();
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FI != FE; ++FI)
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Changed |= runOnMachineBasicBlock(*FI);
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return Changed;
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}
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};
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char Filler::ID = 0;
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} // end of anonymous namespace
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/// runOnMachineBasicBlock - Fill in delay slots for the given basic block.
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/// Currently, we fill delay slots with NOPs. We assume there is only one
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/// delay slot per delayed instruction.
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bool Filler::
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runOnMachineBasicBlock(MachineBasicBlock &MBB)
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{
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bool Changed = false;
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for (MachineBasicBlock::iterator I = MBB.begin(); I != MBB.end(); ++I) {
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const TargetInstrDesc& Tid = I->getDesc();
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if (Tid.hasDelaySlot() &&
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(TM.getSubtarget<MipsSubtarget>().isMips1() ||
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Tid.isCall() || Tid.isBranch() || Tid.isReturn())) {
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MachineBasicBlock::iterator J = I;
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++J;
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BuildMI(MBB, J, I->getDebugLoc(), TII->get(Mips::NOP));
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++FilledSlots;
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Changed = true;
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}
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}
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return Changed;
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}
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/// createMipsDelaySlotFillerPass - Returns a pass that fills in delay
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/// slots in Mips MachineFunctions
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FunctionPass *llvm::createMipsDelaySlotFillerPass(MipsTargetMachine &tm) {
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return new Filler(tm);
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}
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