MachineInstrBundle.cpp revision 396618b43a85e12d290a90b181c6af5d7c0c5f11 
1//===-- lib/CodeGen/MachineInstrBundle.cpp --------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#include "llvm/CodeGen/MachineInstrBundle.h"
11#include "llvm/CodeGen/MachineInstrBuilder.h"
12#include "llvm/CodeGen/Passes.h"
13#include "llvm/CodeGen/MachineFunctionPass.h"
14#include "llvm/Target/TargetInstrInfo.h"
15#include "llvm/Target/TargetMachine.h"
16#include "llvm/Target/TargetRegisterInfo.h"
17#include "llvm/ADT/SmallSet.h"
18#include "llvm/ADT/SmallVector.h"
19using namespace llvm;
20
21namespace {
22  class UnpackMachineBundles : public MachineFunctionPass {
23  public:
24    static char ID; // Pass identification
25    UnpackMachineBundles() : MachineFunctionPass(ID) {
26      initializeUnpackMachineBundlesPass(*PassRegistry::getPassRegistry());
27    }
28
29    virtual bool runOnMachineFunction(MachineFunction &MF);
30  };
31} // end anonymous namespace
32
33char UnpackMachineBundles::ID = 0;
34char &llvm::UnpackMachineBundlesID = UnpackMachineBundles::ID;
35INITIALIZE_PASS(UnpackMachineBundles, "unpack-mi-bundles",
36                "Unpack machine instruction bundles", false, false)
37
38bool UnpackMachineBundles::runOnMachineFunction(MachineFunction &MF) {
39  bool Changed = false;
40  for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
41    MachineBasicBlock *MBB = &*I;
42
43    for (MachineBasicBlock::instr_iterator MII = MBB->instr_begin(),
44           MIE = MBB->instr_end(); MII != MIE; ) {
45      MachineInstr *MI = &*MII;
46
47      // Remove BUNDLE instruction and the InsideBundle flags from bundled
48      // instructions.
49      if (MI->isBundle()) {
50        while (++MII != MIE && MII->isInsideBundle()) {
51          MII->setIsInsideBundle(false);
52          for (unsigned i = 0, e = MII->getNumOperands(); i != e; ++i) {
53            MachineOperand &MO = MII->getOperand(i);
54            if (MO.isReg() && MO.isInternalRead())
55              MO.setIsInternalRead(false);
56          }
57        }
58        MI->eraseFromParent();
59
60        Changed = true;
61        continue;
62      }
63
64      ++MII;
65    }
66  }
67
68  return Changed;
69}
70
71
72namespace {
73  class FinalizeMachineBundles : public MachineFunctionPass {
74  public:
75    static char ID; // Pass identification
76    FinalizeMachineBundles() : MachineFunctionPass(ID) {
77      initializeFinalizeMachineBundlesPass(*PassRegistry::getPassRegistry());
78    }
79
80    virtual bool runOnMachineFunction(MachineFunction &MF);
81  };
82} // end anonymous namespace
83
84char FinalizeMachineBundles::ID = 0;
85char &llvm::FinalizeMachineBundlesID = FinalizeMachineBundles::ID;
86INITIALIZE_PASS(FinalizeMachineBundles, "finalize-mi-bundles",
87                "Finalize machine instruction bundles", false, false)
88
89bool FinalizeMachineBundles::runOnMachineFunction(MachineFunction &MF) {
90  return llvm::finalizeBundles(MF);
91}
92
93
94/// finalizeBundle - Finalize a machine instruction bundle which includes
95/// a sequence of instructions starting from FirstMI to LastMI (exclusive).
96/// This routine adds a BUNDLE instruction to represent the bundle, it adds
97/// IsInternalRead markers to MachineOperands which are defined inside the
98/// bundle, and it copies externally visible defs and uses to the BUNDLE
99/// instruction.
100void llvm::finalizeBundle(MachineBasicBlock &MBB,
101                          MachineBasicBlock::instr_iterator FirstMI,
102                          MachineBasicBlock::instr_iterator LastMI) {
103  assert(FirstMI != LastMI && "Empty bundle?");
104
105  const TargetMachine &TM = MBB.getParent()->getTarget();
106  const TargetInstrInfo *TII = TM.getInstrInfo();
107  const TargetRegisterInfo *TRI = TM.getRegisterInfo();
108
109  MachineInstrBuilder MIB = BuildMI(MBB, FirstMI, FirstMI->getDebugLoc(),
110                                    TII->get(TargetOpcode::BUNDLE));
111
112  SmallVector<unsigned, 8> LocalDefs;
113  SmallSet<unsigned, 8> LocalDefSet;
114  SmallSet<unsigned, 8> DeadDefSet;
115  SmallSet<unsigned, 8> KilledDefSet;
116  SmallVector<unsigned, 8> ExternUses;
117  SmallSet<unsigned, 8> ExternUseSet;
118  SmallSet<unsigned, 8> KilledUseSet;
119  SmallSet<unsigned, 8> UndefUseSet;
120  SmallVector<MachineOperand*, 4> Defs;
121  for (; FirstMI != LastMI; ++FirstMI) {
122    for (unsigned i = 0, e = FirstMI->getNumOperands(); i != e; ++i) {
123      MachineOperand &MO = FirstMI->getOperand(i);
124      if (!MO.isReg())
125        continue;
126      if (MO.isDef()) {
127        Defs.push_back(&MO);
128        continue;
129      }
130
131      unsigned Reg = MO.getReg();
132      if (!Reg)
133        continue;
134      assert(TargetRegisterInfo::isPhysicalRegister(Reg));
135      if (LocalDefSet.count(Reg)) {
136        MO.setIsInternalRead();
137        if (MO.isKill())
138          // Internal def is now killed.
139          KilledDefSet.insert(Reg);
140      } else {
141        if (ExternUseSet.insert(Reg)) {
142          ExternUses.push_back(Reg);
143          if (MO.isUndef())
144            UndefUseSet.insert(Reg);
145        }
146        if (MO.isKill())
147          // External def is now killed.
148          KilledUseSet.insert(Reg);
149      }
150    }
151
152    for (unsigned i = 0, e = Defs.size(); i != e; ++i) {
153      MachineOperand &MO = *Defs[i];
154      unsigned Reg = MO.getReg();
155      if (!Reg)
156        continue;
157
158      if (LocalDefSet.insert(Reg)) {
159        LocalDefs.push_back(Reg);
160        if (MO.isDead()) {
161          DeadDefSet.insert(Reg);
162        }
163      } else {
164        // Re-defined inside the bundle, it's no longer killed.
165        KilledDefSet.erase(Reg);
166        if (!MO.isDead())
167          // Previously defined but dead.
168          DeadDefSet.erase(Reg);
169      }
170
171      if (!MO.isDead()) {
172        for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs) {
173          unsigned SubReg = *SubRegs;
174          if (LocalDefSet.insert(SubReg))
175            LocalDefs.push_back(SubReg);
176        }
177      }
178    }
179
180    FirstMI->setIsInsideBundle();
181    Defs.clear();
182  }
183
184  SmallSet<unsigned, 8> Added;
185  for (unsigned i = 0, e = LocalDefs.size(); i != e; ++i) {
186    unsigned Reg = LocalDefs[i];
187    if (Added.insert(Reg)) {
188      // If it's not live beyond end of the bundle, mark it dead.
189      bool isDead = DeadDefSet.count(Reg) || KilledDefSet.count(Reg);
190      MIB.addReg(Reg, getDefRegState(true) | getDeadRegState(isDead) |
191                 getImplRegState(true));
192    }
193  }
194
195  for (unsigned i = 0, e = ExternUses.size(); i != e; ++i) {
196    unsigned Reg = ExternUses[i];
197    bool isKill = KilledUseSet.count(Reg);
198    bool isUndef = UndefUseSet.count(Reg);
199    MIB.addReg(Reg, getKillRegState(isKill) | getUndefRegState(isUndef) |
200               getImplRegState(true));
201  }
202}
203
204/// finalizeBundle - Same functionality as the previous finalizeBundle except
205/// the last instruction in the bundle is not provided as an input. This is
206/// used in cases where bundles are pre-determined by marking instructions
207/// with 'InsideBundle' marker. It returns the MBB instruction iterator that
208/// points to the end of the bundle.
209MachineBasicBlock::instr_iterator
210llvm::finalizeBundle(MachineBasicBlock &MBB,
211                     MachineBasicBlock::instr_iterator FirstMI) {
212  MachineBasicBlock::instr_iterator E = MBB.instr_end();
213  MachineBasicBlock::instr_iterator LastMI = llvm::next(FirstMI);
214  while (LastMI != E && LastMI->isInsideBundle())
215    ++LastMI;
216  finalizeBundle(MBB, FirstMI, LastMI);
217  return LastMI;
218}
219
220/// finalizeBundles - Finalize instruction bundles in the specified
221/// MachineFunction. Return true if any bundles are finalized.
222bool llvm::finalizeBundles(MachineFunction &MF) {
223  bool Changed = false;
224  for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
225    MachineBasicBlock &MBB = *I;
226
227    MachineBasicBlock::instr_iterator MII = MBB.instr_begin();
228    assert(!MII->isInsideBundle() &&
229           "First instr cannot be inside bundle before finalization!");
230
231    MachineBasicBlock::instr_iterator MIE = MBB.instr_end();
232    if (MII == MIE)
233      continue;
234    for (++MII; MII != MIE; ) {
235      if (!MII->isInsideBundle())
236        ++MII;
237      else {
238        MII = finalizeBundle(MBB, llvm::prior(MII));
239        Changed = true;
240      }
241    }
242  }
243
244  return Changed;
245}
246
247//===----------------------------------------------------------------------===//
248// MachineOperand iterator
249//===----------------------------------------------------------------------===//
250
251MachineOperandIteratorBase::RegInfo
252MachineOperandIteratorBase::analyzeVirtReg(unsigned Reg,
253                    SmallVectorImpl<std::pair<MachineInstr*, unsigned> > *Ops) {
254  RegInfo RI = { false, false, false };
255  for(; isValid(); ++*this) {
256    MachineOperand &MO = deref();
257    if (!MO.isReg() || MO.getReg() != Reg)
258      continue;
259
260    // Remember each (MI, OpNo) that refers to Reg.
261    if (Ops)
262      Ops->push_back(std::make_pair(MO.getParent(), getOperandNo()));
263
264    // Both defs and uses can read virtual registers.
265    if (MO.readsReg()) {
266      RI.Reads = true;
267      if (MO.isDef())
268        RI.Tied = true;
269    }
270
271    // Only defs can write.
272    if (MO.isDef())
273      RI.Writes = true;
274    else if (!RI.Tied && MO.getParent()->isRegTiedToDefOperand(getOperandNo()))
275      RI.Tied = true;
276  }
277  return RI;
278}
279