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/ADT/SmallSet.h"
12 #include "llvm/ADT/SmallVector.h"
13 #include "llvm/CodeGen/MachineFunctionPass.h"
14 #include "llvm/CodeGen/MachineInstrBuilder.h"
15 #include "llvm/CodeGen/Passes.h"
16 #include "llvm/Target/TargetInstrInfo.h"
17 #include "llvm/Target/TargetMachine.h"
18 #include "llvm/Target/TargetRegisterInfo.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 bool runOnMachineFunction(MachineFunction &MF) override;
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->isBundledWithPred()) {
51 MII->unbundleFromPred();
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 bool runOnMachineFunction(MachineFunction &MF) override;
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 MIBundleBuilder Bundle(MBB, FirstMI, LastMI);
105
106 const TargetMachine &TM = MBB.getParent()->getTarget();
107 const TargetInstrInfo *TII = TM.getInstrInfo();
108 const TargetRegisterInfo *TRI = TM.getRegisterInfo();
109
110 MachineInstrBuilder MIB = BuildMI(*MBB.getParent(), FirstMI->getDebugLoc(),
111 TII->get(TargetOpcode::BUNDLE));
112 Bundle.prepend(MIB);
113
114 SmallVector<unsigned, 32> LocalDefs;
115 SmallSet<unsigned, 32> LocalDefSet;
116 SmallSet<unsigned, 8> DeadDefSet;
117 SmallSet<unsigned, 16> KilledDefSet;
118 SmallVector<unsigned, 8> ExternUses;
119 SmallSet<unsigned, 8> ExternUseSet;
120 SmallSet<unsigned, 8> KilledUseSet;
121 SmallSet<unsigned, 8> UndefUseSet;
122 SmallVector<MachineOperand*, 4> Defs;
123 for (; FirstMI != LastMI; ++FirstMI) {
124 for (unsigned i = 0, e = FirstMI->getNumOperands(); i != e; ++i) {
125 MachineOperand &MO = FirstMI->getOperand(i);
126 if (!MO.isReg())
127 continue;
128 if (MO.isDef()) {
129 Defs.push_back(&MO);
130 continue;
131 }
132
133 unsigned Reg = MO.getReg();
134 if (!Reg)
135 continue;
136 assert(TargetRegisterInfo::isPhysicalRegister(Reg));
137 if (LocalDefSet.count(Reg)) {
138 MO.setIsInternalRead();
139 if (MO.isKill())
140 // Internal def is now killed.
141 KilledDefSet.insert(Reg);
142 } else {
143 if (ExternUseSet.insert(Reg)) {
144 ExternUses.push_back(Reg);
145 if (MO.isUndef())
146 UndefUseSet.insert(Reg);
147 }
148 if (MO.isKill())
149 // External def is now killed.
150 KilledUseSet.insert(Reg);
151 }
152 }
153
154 for (unsigned i = 0, e = Defs.size(); i != e; ++i) {
155 MachineOperand &MO = *Defs[i];
156 unsigned Reg = MO.getReg();
157 if (!Reg)
158 continue;
159
160 if (LocalDefSet.insert(Reg)) {
161 LocalDefs.push_back(Reg);
162 if (MO.isDead()) {
163 DeadDefSet.insert(Reg);
164 }
165 } else {
166 // Re-defined inside the bundle, it's no longer killed.
167 KilledDefSet.erase(Reg);
168 if (!MO.isDead())
169 // Previously defined but dead.
170 DeadDefSet.erase(Reg);
171 }
172
173 if (!MO.isDead()) {
174 for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs) {
175 unsigned SubReg = *SubRegs;
176 if (LocalDefSet.insert(SubReg))
177 LocalDefs.push_back(SubReg);
178 }
179 }
180 }
181
182 Defs.clear();
183 }
184
185 SmallSet<unsigned, 32> Added;
186 for (unsigned i = 0, e = LocalDefs.size(); i != e; ++i) {
187 unsigned Reg = LocalDefs[i];
188 if (Added.insert(Reg)) {
189 // If it's not live beyond end of the bundle, mark it dead.
190 bool isDead = DeadDefSet.count(Reg) || KilledDefSet.count(Reg);
191 MIB.addReg(Reg, getDefRegState(true) | getDeadRegState(isDead) |
192 getImplRegState(true));
193 }
194 }
195
196 for (unsigned i = 0, e = ExternUses.size(); i != e; ++i) {
197 unsigned Reg = ExternUses[i];
198 bool isKill = KilledUseSet.count(Reg);
199 bool isUndef = UndefUseSet.count(Reg);
200 MIB.addReg(Reg, getKillRegState(isKill) | getUndefRegState(isUndef) |
201 getImplRegState(true));
202 }
203 }
204
205 /// finalizeBundle - Same functionality as the previous finalizeBundle except
206 /// the last instruction in the bundle is not provided as an input. This is
207 /// used in cases where bundles are pre-determined by marking instructions
208 /// with 'InsideBundle' marker. It returns the MBB instruction iterator that
209 /// points to the end of the bundle.
210 MachineBasicBlock::instr_iterator
finalizeBundle(MachineBasicBlock & MBB,MachineBasicBlock::instr_iterator FirstMI)211 llvm::finalizeBundle(MachineBasicBlock &MBB,
212 MachineBasicBlock::instr_iterator FirstMI) {
213 MachineBasicBlock::instr_iterator E = MBB.instr_end();
214 MachineBasicBlock::instr_iterator LastMI = std::next(FirstMI);
215 while (LastMI != E && LastMI->isInsideBundle())
216 ++LastMI;
217 finalizeBundle(MBB, FirstMI, LastMI);
218 return LastMI;
219 }
220
221 /// finalizeBundles - Finalize instruction bundles in the specified
222 /// MachineFunction. Return true if any bundles are finalized.
finalizeBundles(MachineFunction & MF)223 bool llvm::finalizeBundles(MachineFunction &MF) {
224 bool Changed = false;
225 for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
226 MachineBasicBlock &MBB = *I;
227 MachineBasicBlock::instr_iterator MII = MBB.instr_begin();
228 MachineBasicBlock::instr_iterator MIE = MBB.instr_end();
229 if (MII == MIE)
230 continue;
231 assert(!MII->isInsideBundle() &&
232 "First instr cannot be inside bundle before finalization!");
233
234 for (++MII; MII != MIE; ) {
235 if (!MII->isInsideBundle())
236 ++MII;
237 else {
238 MII = finalizeBundle(MBB, std::prev(MII));
239 Changed = true;
240 }
241 }
242 }
243
244 return Changed;
245 }
246
247 //===----------------------------------------------------------------------===//
248 // MachineOperand iterator
249 //===----------------------------------------------------------------------===//
250
251 MachineOperandIteratorBase::VirtRegInfo
analyzeVirtReg(unsigned Reg,SmallVectorImpl<std::pair<MachineInstr *,unsigned>> * Ops)252 MachineOperandIteratorBase::analyzeVirtReg(unsigned Reg,
253 SmallVectorImpl<std::pair<MachineInstr*, unsigned> > *Ops) {
254 VirtRegInfo 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
280 MachineOperandIteratorBase::PhysRegInfo
analyzePhysReg(unsigned Reg,const TargetRegisterInfo * TRI)281 MachineOperandIteratorBase::analyzePhysReg(unsigned Reg,
282 const TargetRegisterInfo *TRI) {
283 bool AllDefsDead = true;
284 PhysRegInfo PRI = {false, false, false, false, false, false};
285
286 assert(TargetRegisterInfo::isPhysicalRegister(Reg) &&
287 "analyzePhysReg not given a physical register!");
288 for (; isValid(); ++*this) {
289 MachineOperand &MO = deref();
290
291 if (MO.isRegMask() && MO.clobbersPhysReg(Reg))
292 PRI.Clobbers = true; // Regmask clobbers Reg.
293
294 if (!MO.isReg())
295 continue;
296
297 unsigned MOReg = MO.getReg();
298 if (!MOReg || !TargetRegisterInfo::isPhysicalRegister(MOReg))
299 continue;
300
301 bool IsRegOrSuperReg = MOReg == Reg || TRI->isSubRegister(MOReg, Reg);
302 bool IsRegOrOverlapping = MOReg == Reg || TRI->regsOverlap(MOReg, Reg);
303
304 if (IsRegOrSuperReg && MO.readsReg()) {
305 // Reg or a super-reg is read, and perhaps killed also.
306 PRI.Reads = true;
307 PRI.Kills = MO.isKill();
308 }
309
310 if (IsRegOrOverlapping && MO.readsReg()) {
311 PRI.ReadsOverlap = true;// Reg or an overlapping register is read.
312 }
313
314 if (!MO.isDef())
315 continue;
316
317 if (IsRegOrSuperReg) {
318 PRI.Defines = true; // Reg or a super-register is defined.
319 if (!MO.isDead())
320 AllDefsDead = false;
321 }
322 if (IsRegOrOverlapping)
323 PRI.Clobbers = true; // Reg or an overlapping reg is defined.
324 }
325
326 if (AllDefsDead && PRI.Defines)
327 PRI.DefinesDead = true; // Reg or super-register was defined and was dead.
328
329 return PRI;
330 }
331