DelaySlotFiller.cpp revision 4185d03dc5290550f0bad33764f3971ec9a74132 
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// Simple local delay slot filler for SparcV8 machine code
11//
12//===----------------------------------------------------------------------===//
13
14#include "SparcV8.h"
15#include "llvm/CodeGen/MachineFunctionPass.h"
16#include "llvm/CodeGen/MachineInstrBuilder.h"
17#include "Support/Statistic.h"
18
19using namespace llvm;
20
21namespace {
22  Statistic<> FilledSlots ("delayslotfiller", "Num. of delay slots filled");
23
24  struct Filler : public MachineFunctionPass {
25    /// Target machine description which we query for reg. names, data
26    /// layout, etc.
27    ///
28    TargetMachine &TM;
29
30    Filler (TargetMachine &tm) : TM (tm) { }
31
32    virtual const char *getPassName () const {
33      return "SparcV8 Delay Slot Filler";
34    }
35
36    bool runOnMachineBasicBlock (MachineBasicBlock &MBB);
37    bool runOnMachineFunction (MachineFunction &F) {
38      bool Changed = false;
39      for (MachineFunction::iterator FI = F.begin (), FE = F.end ();
40           FI != FE; ++FI)
41        Changed |= runOnMachineBasicBlock (*FI);
42      return Changed;
43    }
44
45  };
46} // end of anonymous namespace
47
48/// createSparcV8DelaySlotFillerPass - Returns a pass that fills in delay
49/// slots in SparcV8 MachineFunctions
50///
51FunctionPass *llvm::createSparcV8DelaySlotFillerPass (TargetMachine &tm) {
52  return new Filler (tm);
53}
54
55static bool hasDelaySlot (unsigned Opcode) {
56  switch (Opcode) {
57    case V8::BA:
58    case V8::BCC:
59    case V8::BCS:
60    case V8::BE:
61    case V8::BG:
62    case V8::BGE:
63    case V8::BGU:
64    case V8::BL:
65    case V8::BLE:
66    case V8::BLEU:
67    case V8::BNE:
68    case V8::CALL:
69    case V8::JMPLrr:
70    case V8::RETL:
71    case V8::FBA:
72    case V8::FBN:
73    case V8::FBU:
74    case V8::FBG:
75    case V8::FBUG:
76    case V8::FBL:
77    case V8::FBUL:
78    case V8::FBLG:
79    case V8::FBNE:
80    case V8::FBE:
81    case V8::FBUE:
82    case V8::FBGE:
83    case V8::FBUGE:
84    case V8::FBLE:
85    case V8::FBULE:
86    case V8::FBO:
87    case V8::FCMPS:
88    case V8::FCMPD:
89    case V8::FCMPES:
90    case V8::FCMPED:
91      return true;
92    default:
93      return false;
94  }
95}
96
97/// runOnMachineBasicBlock - Fill in delay slots for the given basic block.
98/// Currently, we fill delay slots with NOPs. We assume there is only one
99/// delay slot per delayed instruction.
100///
101bool Filler::runOnMachineBasicBlock (MachineBasicBlock &MBB) {
102  bool Changed = false;
103  for (MachineBasicBlock::iterator I = MBB.begin (); I != MBB.end (); ++I)
104    if (hasDelaySlot (I->getOpcode ())) {
105      MachineBasicBlock::iterator J = I;
106      ++J;
107      BuildMI (MBB, J, V8::NOP, 0);
108      ++FilledSlots;
109      Changed = true;
110    }
111  return Changed;
112}
113