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 #include "llvm/Target/TargetSubtargetInfo.h"
20 #include <utility>
21 using namespace llvm;
22
23 namespace {
24 class UnpackMachineBundles : public MachineFunctionPass {
25 public:
26 static char ID; // Pass identification
UnpackMachineBundles(std::function<bool (const Function &)> Ftor=nullptr)27 UnpackMachineBundles(std::function<bool(const Function &)> Ftor = nullptr)
28 : MachineFunctionPass(ID), PredicateFtor(std::move(Ftor)) {
29 initializeUnpackMachineBundlesPass(*PassRegistry::getPassRegistry());
30 }
31
32 bool runOnMachineFunction(MachineFunction &MF) override;
33
34 private:
35 std::function<bool(const Function &)> PredicateFtor;
36 };
37 } // end anonymous namespace
38
39 char UnpackMachineBundles::ID = 0;
40 char &llvm::UnpackMachineBundlesID = UnpackMachineBundles::ID;
41 INITIALIZE_PASS(UnpackMachineBundles, "unpack-mi-bundles",
42 "Unpack machine instruction bundles", false, false)
43
runOnMachineFunction(MachineFunction & MF)44 bool UnpackMachineBundles::runOnMachineFunction(MachineFunction &MF) {
45 if (PredicateFtor && !PredicateFtor(*MF.getFunction()))
46 return false;
47
48 bool Changed = false;
49 for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
50 MachineBasicBlock *MBB = &*I;
51
52 for (MachineBasicBlock::instr_iterator MII = MBB->instr_begin(),
53 MIE = MBB->instr_end(); MII != MIE; ) {
54 MachineInstr *MI = &*MII;
55
56 // Remove BUNDLE instruction and the InsideBundle flags from bundled
57 // instructions.
58 if (MI->isBundle()) {
59 while (++MII != MIE && MII->isBundledWithPred()) {
60 MII->unbundleFromPred();
61 for (unsigned i = 0, e = MII->getNumOperands(); i != e; ++i) {
62 MachineOperand &MO = MII->getOperand(i);
63 if (MO.isReg() && MO.isInternalRead())
64 MO.setIsInternalRead(false);
65 }
66 }
67 MI->eraseFromParent();
68
69 Changed = true;
70 continue;
71 }
72
73 ++MII;
74 }
75 }
76
77 return Changed;
78 }
79
80 FunctionPass *
createUnpackMachineBundles(std::function<bool (const Function &)> Ftor)81 llvm::createUnpackMachineBundles(std::function<bool(const Function &)> Ftor) {
82 return new UnpackMachineBundles(std::move(Ftor));
83 }
84
85 namespace {
86 class FinalizeMachineBundles : public MachineFunctionPass {
87 public:
88 static char ID; // Pass identification
FinalizeMachineBundles()89 FinalizeMachineBundles() : MachineFunctionPass(ID) {
90 initializeFinalizeMachineBundlesPass(*PassRegistry::getPassRegistry());
91 }
92
93 bool runOnMachineFunction(MachineFunction &MF) override;
94 };
95 } // end anonymous namespace
96
97 char FinalizeMachineBundles::ID = 0;
98 char &llvm::FinalizeMachineBundlesID = FinalizeMachineBundles::ID;
99 INITIALIZE_PASS(FinalizeMachineBundles, "finalize-mi-bundles",
100 "Finalize machine instruction bundles", false, false)
101
runOnMachineFunction(MachineFunction & MF)102 bool FinalizeMachineBundles::runOnMachineFunction(MachineFunction &MF) {
103 return llvm::finalizeBundles(MF);
104 }
105
106
107 /// finalizeBundle - Finalize a machine instruction bundle which includes
108 /// a sequence of instructions starting from FirstMI to LastMI (exclusive).
109 /// This routine adds a BUNDLE instruction to represent the bundle, it adds
110 /// IsInternalRead markers to MachineOperands which are defined inside the
111 /// bundle, and it copies externally visible defs and uses to the BUNDLE
112 /// instruction.
finalizeBundle(MachineBasicBlock & MBB,MachineBasicBlock::instr_iterator FirstMI,MachineBasicBlock::instr_iterator LastMI)113 void llvm::finalizeBundle(MachineBasicBlock &MBB,
114 MachineBasicBlock::instr_iterator FirstMI,
115 MachineBasicBlock::instr_iterator LastMI) {
116 assert(FirstMI != LastMI && "Empty bundle?");
117 MIBundleBuilder Bundle(MBB, FirstMI, LastMI);
118
119 MachineFunction &MF = *MBB.getParent();
120 const TargetInstrInfo *TII = MF.getSubtarget().getInstrInfo();
121 const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo();
122
123 MachineInstrBuilder MIB =
124 BuildMI(MF, FirstMI->getDebugLoc(), TII->get(TargetOpcode::BUNDLE));
125 Bundle.prepend(MIB);
126
127 SmallVector<unsigned, 32> LocalDefs;
128 SmallSet<unsigned, 32> LocalDefSet;
129 SmallSet<unsigned, 8> DeadDefSet;
130 SmallSet<unsigned, 16> KilledDefSet;
131 SmallVector<unsigned, 8> ExternUses;
132 SmallSet<unsigned, 8> ExternUseSet;
133 SmallSet<unsigned, 8> KilledUseSet;
134 SmallSet<unsigned, 8> UndefUseSet;
135 SmallVector<MachineOperand*, 4> Defs;
136 for (; FirstMI != LastMI; ++FirstMI) {
137 for (unsigned i = 0, e = FirstMI->getNumOperands(); i != e; ++i) {
138 MachineOperand &MO = FirstMI->getOperand(i);
139 if (!MO.isReg())
140 continue;
141 if (MO.isDef()) {
142 Defs.push_back(&MO);
143 continue;
144 }
145
146 unsigned Reg = MO.getReg();
147 if (!Reg)
148 continue;
149 assert(TargetRegisterInfo::isPhysicalRegister(Reg));
150 if (LocalDefSet.count(Reg)) {
151 MO.setIsInternalRead();
152 if (MO.isKill())
153 // Internal def is now killed.
154 KilledDefSet.insert(Reg);
155 } else {
156 if (ExternUseSet.insert(Reg).second) {
157 ExternUses.push_back(Reg);
158 if (MO.isUndef())
159 UndefUseSet.insert(Reg);
160 }
161 if (MO.isKill())
162 // External def is now killed.
163 KilledUseSet.insert(Reg);
164 }
165 }
166
167 for (unsigned i = 0, e = Defs.size(); i != e; ++i) {
168 MachineOperand &MO = *Defs[i];
169 unsigned Reg = MO.getReg();
170 if (!Reg)
171 continue;
172
173 if (LocalDefSet.insert(Reg).second) {
174 LocalDefs.push_back(Reg);
175 if (MO.isDead()) {
176 DeadDefSet.insert(Reg);
177 }
178 } else {
179 // Re-defined inside the bundle, it's no longer killed.
180 KilledDefSet.erase(Reg);
181 if (!MO.isDead())
182 // Previously defined but dead.
183 DeadDefSet.erase(Reg);
184 }
185
186 if (!MO.isDead()) {
187 for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs) {
188 unsigned SubReg = *SubRegs;
189 if (LocalDefSet.insert(SubReg).second)
190 LocalDefs.push_back(SubReg);
191 }
192 }
193 }
194
195 Defs.clear();
196 }
197
198 SmallSet<unsigned, 32> Added;
199 for (unsigned i = 0, e = LocalDefs.size(); i != e; ++i) {
200 unsigned Reg = LocalDefs[i];
201 if (Added.insert(Reg).second) {
202 // If it's not live beyond end of the bundle, mark it dead.
203 bool isDead = DeadDefSet.count(Reg) || KilledDefSet.count(Reg);
204 MIB.addReg(Reg, getDefRegState(true) | getDeadRegState(isDead) |
205 getImplRegState(true));
206 }
207 }
208
209 for (unsigned i = 0, e = ExternUses.size(); i != e; ++i) {
210 unsigned Reg = ExternUses[i];
211 bool isKill = KilledUseSet.count(Reg);
212 bool isUndef = UndefUseSet.count(Reg);
213 MIB.addReg(Reg, getKillRegState(isKill) | getUndefRegState(isUndef) |
214 getImplRegState(true));
215 }
216 }
217
218 /// finalizeBundle - Same functionality as the previous finalizeBundle except
219 /// the last instruction in the bundle is not provided as an input. This is
220 /// used in cases where bundles are pre-determined by marking instructions
221 /// with 'InsideBundle' marker. It returns the MBB instruction iterator that
222 /// points to the end of the bundle.
223 MachineBasicBlock::instr_iterator
finalizeBundle(MachineBasicBlock & MBB,MachineBasicBlock::instr_iterator FirstMI)224 llvm::finalizeBundle(MachineBasicBlock &MBB,
225 MachineBasicBlock::instr_iterator FirstMI) {
226 MachineBasicBlock::instr_iterator E = MBB.instr_end();
227 MachineBasicBlock::instr_iterator LastMI = std::next(FirstMI);
228 while (LastMI != E && LastMI->isInsideBundle())
229 ++LastMI;
230 finalizeBundle(MBB, FirstMI, LastMI);
231 return LastMI;
232 }
233
234 /// finalizeBundles - Finalize instruction bundles in the specified
235 /// MachineFunction. Return true if any bundles are finalized.
finalizeBundles(MachineFunction & MF)236 bool llvm::finalizeBundles(MachineFunction &MF) {
237 bool Changed = false;
238 for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
239 MachineBasicBlock &MBB = *I;
240 MachineBasicBlock::instr_iterator MII = MBB.instr_begin();
241 MachineBasicBlock::instr_iterator MIE = MBB.instr_end();
242 if (MII == MIE)
243 continue;
244 assert(!MII->isInsideBundle() &&
245 "First instr cannot be inside bundle before finalization!");
246
247 for (++MII; MII != MIE; ) {
248 if (!MII->isInsideBundle())
249 ++MII;
250 else {
251 MII = finalizeBundle(MBB, std::prev(MII));
252 Changed = true;
253 }
254 }
255 }
256
257 return Changed;
258 }
259
260 //===----------------------------------------------------------------------===//
261 // MachineOperand iterator
262 //===----------------------------------------------------------------------===//
263
264 MachineOperandIteratorBase::VirtRegInfo
analyzeVirtReg(unsigned Reg,SmallVectorImpl<std::pair<MachineInstr *,unsigned>> * Ops)265 MachineOperandIteratorBase::analyzeVirtReg(unsigned Reg,
266 SmallVectorImpl<std::pair<MachineInstr*, unsigned> > *Ops) {
267 VirtRegInfo RI = { false, false, false };
268 for(; isValid(); ++*this) {
269 MachineOperand &MO = deref();
270 if (!MO.isReg() || MO.getReg() != Reg)
271 continue;
272
273 // Remember each (MI, OpNo) that refers to Reg.
274 if (Ops)
275 Ops->push_back(std::make_pair(MO.getParent(), getOperandNo()));
276
277 // Both defs and uses can read virtual registers.
278 if (MO.readsReg()) {
279 RI.Reads = true;
280 if (MO.isDef())
281 RI.Tied = true;
282 }
283
284 // Only defs can write.
285 if (MO.isDef())
286 RI.Writes = true;
287 else if (!RI.Tied && MO.getParent()->isRegTiedToDefOperand(getOperandNo()))
288 RI.Tied = true;
289 }
290 return RI;
291 }
292
293 MachineOperandIteratorBase::PhysRegInfo
analyzePhysReg(unsigned Reg,const TargetRegisterInfo * TRI)294 MachineOperandIteratorBase::analyzePhysReg(unsigned Reg,
295 const TargetRegisterInfo *TRI) {
296 bool AllDefsDead = true;
297 PhysRegInfo PRI = {false, false, false, false, false, false, false, false};
298
299 assert(TargetRegisterInfo::isPhysicalRegister(Reg) &&
300 "analyzePhysReg not given a physical register!");
301 for (; isValid(); ++*this) {
302 MachineOperand &MO = deref();
303
304 if (MO.isRegMask() && MO.clobbersPhysReg(Reg)) {
305 PRI.Clobbered = true;
306 continue;
307 }
308
309 if (!MO.isReg())
310 continue;
311
312 unsigned MOReg = MO.getReg();
313 if (!MOReg || !TargetRegisterInfo::isPhysicalRegister(MOReg))
314 continue;
315
316 if (!TRI->regsOverlap(MOReg, Reg))
317 continue;
318
319 bool Covered = TRI->isSuperRegisterEq(Reg, MOReg);
320 if (MO.readsReg()) {
321 PRI.Read = true;
322 if (Covered) {
323 PRI.FullyRead = true;
324 if (MO.isKill())
325 PRI.Killed = true;
326 }
327 } else if (MO.isDef()) {
328 PRI.Defined = true;
329 if (Covered)
330 PRI.FullyDefined = true;
331 if (!MO.isDead())
332 AllDefsDead = false;
333 }
334 }
335
336 if (AllDefsDead) {
337 if (PRI.FullyDefined || PRI.Clobbered)
338 PRI.DeadDef = true;
339 else if (PRI.Defined)
340 PRI.PartialDeadDef = true;
341 }
342
343 return PRI;
344 }
345