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"
19 using namespace llvm;
20
21 namespace {
22 class UnpackMachineBundles : public MachineFunctionPass {
23 public:
24 static char ID; // Pass identification
UnpackMachineBundles()25 UnpackMachineBundles() : MachineFunctionPass(ID) {
26 initializeUnpackMachineBundlesPass(*PassRegistry::getPassRegistry());
27 }
28
29 virtual bool runOnMachineFunction(MachineFunction &MF);
30 };
31 } // end anonymous namespace
32
33 char UnpackMachineBundles::ID = 0;
34 char &llvm::UnpackMachineBundlesID = UnpackMachineBundles::ID;
35 INITIALIZE_PASS(UnpackMachineBundles, "unpack-mi-bundles",
36 "Unpack machine instruction bundles", false, false)
37
runOnMachineFunction(MachineFunction & MF)38 bool 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
72 namespace {
73 class FinalizeMachineBundles : public MachineFunctionPass {
74 public:
75 static char ID; // Pass identification
FinalizeMachineBundles()76 FinalizeMachineBundles() : MachineFunctionPass(ID) {
77 initializeFinalizeMachineBundlesPass(*PassRegistry::getPassRegistry());
78 }
79
80 virtual bool runOnMachineFunction(MachineFunction &MF);
81 };
82 } // end anonymous namespace
83
84 char FinalizeMachineBundles::ID = 0;
85 char &llvm::FinalizeMachineBundlesID = FinalizeMachineBundles::ID;
86 INITIALIZE_PASS(FinalizeMachineBundles, "finalize-mi-bundles",
87 "Finalize machine instruction bundles", false, false)
88
runOnMachineFunction(MachineFunction & MF)89 bool 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.
finalizeBundle(MachineBasicBlock & MBB,MachineBasicBlock::instr_iterator FirstMI,MachineBasicBlock::instr_iterator LastMI)100 void 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.
209 MachineBasicBlock::instr_iterator
finalizeBundle(MachineBasicBlock & MBB,MachineBasicBlock::instr_iterator FirstMI)210 llvm::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.
finalizeBundles(MachineFunction & MF)222 bool 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
251 MachineOperandIteratorBase::RegInfo
analyzeVirtReg(unsigned Reg,SmallVectorImpl<std::pair<MachineInstr *,unsigned>> * Ops)252 MachineOperandIteratorBase::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