llvm/llvm/lib/Target/Lanai/LanaiDelaySlotFiller.cpp

//===-- LanaiDelaySlotFiller.cpp - Lanai delay slot filler ----------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Simple pass to fill delay slots with useful instructions.
//
//===----------------------------------------------------------------------===//

#include "Lanai.h"
#include "LanaiTargetMachine.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
#include "llvm/Support/CommandLine.h"

usingnamespacellvm;

#define DEBUG_TYPE …

STATISTIC(FilledSlots, "Number of delay slots filled");

static cl::opt<bool>
    NopDelaySlotFiller("lanai-nop-delay-filler", cl::init(false),
                       cl::desc("Fill Lanai delay slots with NOPs."),
                       cl::Hidden);

namespace {
struct Filler : public MachineFunctionPass { … };
char Filler::ID = …;
} // end of anonymous namespace

// createLanaiDelaySlotFillerPass - Returns a pass that fills in delay
// slots in Lanai MachineFunctions
FunctionPass *
llvm::createLanaiDelaySlotFillerPass(const LanaiTargetMachine & /*tm*/) { … }

// runOnMachineBasicBlock - Fill in delay slots for the given basic block.
// There is one or two delay slot per delayed instruction.
bool Filler::runOnMachineBasicBlock(MachineBasicBlock &MBB) { … }

bool Filler::findDelayInstr(MachineBasicBlock &MBB,
                            MachineBasicBlock::instr_iterator Slot,
                            MachineBasicBlock::instr_iterator &Filler) { … }

bool Filler::delayHasHazard(MachineBasicBlock::instr_iterator MI, bool &SawLoad,
                            bool &SawStore, SmallSet<unsigned, 32> &RegDefs,
                            SmallSet<unsigned, 32> &RegUses) { … }

// Insert Defs and Uses of MI into the sets RegDefs and RegUses.
void Filler::insertDefsUses(MachineBasicBlock::instr_iterator MI,
                            SmallSet<unsigned, 32> &RegDefs,
                            SmallSet<unsigned, 32> &RegUses) { … }

// Returns true if the Reg or its alias is in the RegSet.
bool Filler::isRegInSet(SmallSet<unsigned, 32> &RegSet, unsigned Reg) { … }