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