DelaySlotFiller.cpp revision 870248b16491c9a9a604494b4e7aa94035af2158 
1//===-- DelaySlotFiller.cpp - SparcV8 delay slot filler -------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by the LLVM research group and is distributed under
6// the University of Illinois Open Source License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This is a simple local pass that fills delay slots with NOPs.
11//
12//===----------------------------------------------------------------------===//
13
14#include "SparcV8.h"
15#include "llvm/CodeGen/MachineFunctionPass.h"
16#include "llvm/CodeGen/MachineInstrBuilder.h"
17#include "llvm/Target/TargetMachine.h"
18#include "llvm/Target/TargetInstrInfo.h"
19#include "llvm/ADT/Statistic.h"
20
21using namespace llvm;
22
23namespace {
24  Statistic<> FilledSlots ("delayslotfiller", "Num. of delay slots filled");
25
26  struct Filler : public MachineFunctionPass {
27    /// Target machine description which we query for reg. names, data
28    /// layout, etc.
29    ///
30    TargetMachine &TM;
31    const TargetInstrInfo *TII;
32
33    Filler (TargetMachine &tm) : TM (tm), TII (tm.getInstrInfo ()) { }
34
35    virtual const char *getPassName () const {
36      return "SparcV8 Delay Slot Filler";
37    }
38
39    bool runOnMachineBasicBlock (MachineBasicBlock &MBB);
40    bool runOnMachineFunction (MachineFunction &F) {
41      bool Changed = false;
42      for (MachineFunction::iterator FI = F.begin (), FE = F.end ();
43           FI != FE; ++FI)
44        Changed |= runOnMachineBasicBlock (*FI);
45      return Changed;
46    }
47
48  };
49} // end of anonymous namespace
50
51/// createSparcV8DelaySlotFillerPass - Returns a pass that fills in delay
52/// slots in SparcV8 MachineFunctions
53///
54FunctionPass *llvm::createSparcV8DelaySlotFillerPass (TargetMachine &tm) {
55  return new Filler (tm);
56}
57
58/// runOnMachineBasicBlock - Fill in delay slots for the given basic block.
59/// Currently, we fill delay slots with NOPs. We assume there is only one
60/// delay slot per delayed instruction.
61///
62bool Filler::runOnMachineBasicBlock (MachineBasicBlock &MBB) {
63  bool Changed = false;
64  for (MachineBasicBlock::iterator I = MBB.begin (); I != MBB.end (); ++I)
65    if (TII->hasDelaySlot (I->getOpcode ())) {
66      MachineBasicBlock::iterator J = I;
67      ++J;
68      BuildMI (MBB, J, V8::NOP, 0);
69      ++FilledSlots;
70      Changed = true;
71    }
72  return Changed;
73}
74