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1 | //===- MachineSink.cpp - Sinking for machine instructions -----------------===// | ||||||||
2 | // | ||||||||
3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. | ||||||||
4 | // See https://llvm.org/LICENSE.txt for license information. | ||||||||
5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception | ||||||||
6 | // | ||||||||
7 | //===----------------------------------------------------------------------===// | ||||||||
8 | // | ||||||||
9 | // This pass moves instructions into successor blocks when possible, so that | ||||||||
10 | // they aren't executed on paths where their results aren't needed. | ||||||||
11 | // | ||||||||
12 | // This pass is not intended to be a replacement or a complete alternative | ||||||||
13 | // for an LLVM-IR-level sinking pass. It is only designed to sink simple | ||||||||
14 | // constructs that are not exposed before lowering and instruction selection. | ||||||||
15 | // | ||||||||
16 | //===----------------------------------------------------------------------===// | ||||||||
17 | |||||||||
18 | #include "llvm/ADT/DenseSet.h" | ||||||||
19 | #include "llvm/ADT/MapVector.h" | ||||||||
20 | #include "llvm/ADT/PointerIntPair.h" | ||||||||
21 | #include "llvm/ADT/SetVector.h" | ||||||||
22 | #include "llvm/ADT/SmallSet.h" | ||||||||
23 | #include "llvm/ADT/SmallVector.h" | ||||||||
24 | #include "llvm/ADT/SparseBitVector.h" | ||||||||
25 | #include "llvm/ADT/Statistic.h" | ||||||||
26 | #include "llvm/Analysis/AliasAnalysis.h" | ||||||||
27 | #include "llvm/CodeGen/MachineBasicBlock.h" | ||||||||
28 | #include "llvm/CodeGen/MachineBlockFrequencyInfo.h" | ||||||||
29 | #include "llvm/CodeGen/MachineBranchProbabilityInfo.h" | ||||||||
30 | #include "llvm/CodeGen/MachineDominators.h" | ||||||||
31 | #include "llvm/CodeGen/MachineFunction.h" | ||||||||
32 | #include "llvm/CodeGen/MachineFunctionPass.h" | ||||||||
33 | #include "llvm/CodeGen/MachineInstr.h" | ||||||||
34 | #include "llvm/CodeGen/MachineLoopInfo.h" | ||||||||
35 | #include "llvm/CodeGen/MachineOperand.h" | ||||||||
36 | #include "llvm/CodeGen/MachinePostDominators.h" | ||||||||
37 | #include "llvm/CodeGen/MachineRegisterInfo.h" | ||||||||
38 | #include "llvm/CodeGen/RegisterClassInfo.h" | ||||||||
39 | #include "llvm/CodeGen/RegisterPressure.h" | ||||||||
40 | #include "llvm/CodeGen/TargetInstrInfo.h" | ||||||||
41 | #include "llvm/CodeGen/TargetRegisterInfo.h" | ||||||||
42 | #include "llvm/CodeGen/TargetSubtargetInfo.h" | ||||||||
43 | #include "llvm/IR/BasicBlock.h" | ||||||||
44 | #include "llvm/IR/DebugInfoMetadata.h" | ||||||||
45 | #include "llvm/IR/LLVMContext.h" | ||||||||
46 | #include "llvm/InitializePasses.h" | ||||||||
47 | #include "llvm/MC/MCRegisterInfo.h" | ||||||||
48 | #include "llvm/Pass.h" | ||||||||
49 | #include "llvm/Support/BranchProbability.h" | ||||||||
50 | #include "llvm/Support/CommandLine.h" | ||||||||
51 | #include "llvm/Support/Debug.h" | ||||||||
52 | #include "llvm/Support/raw_ostream.h" | ||||||||
53 | #include <algorithm> | ||||||||
54 | #include <cassert> | ||||||||
55 | #include <cstdint> | ||||||||
56 | #include <map> | ||||||||
57 | #include <utility> | ||||||||
58 | #include <vector> | ||||||||
59 | |||||||||
60 | using namespace llvm; | ||||||||
61 | |||||||||
62 | #define DEBUG_TYPE"machine-sink" "machine-sink" | ||||||||
63 | |||||||||
64 | static cl::opt<bool> | ||||||||
65 | SplitEdges("machine-sink-split", | ||||||||
66 | cl::desc("Split critical edges during machine sinking"), | ||||||||
67 | cl::init(true), cl::Hidden); | ||||||||
68 | |||||||||
69 | static cl::opt<bool> | ||||||||
70 | UseBlockFreqInfo("machine-sink-bfi", | ||||||||
71 | cl::desc("Use block frequency info to find successors to sink"), | ||||||||
72 | cl::init(true), cl::Hidden); | ||||||||
73 | |||||||||
74 | static cl::opt<unsigned> SplitEdgeProbabilityThreshold( | ||||||||
75 | "machine-sink-split-probability-threshold", | ||||||||
76 | cl::desc( | ||||||||
77 | "Percentage threshold for splitting single-instruction critical edge. " | ||||||||
78 | "If the branch threshold is higher than this threshold, we allow " | ||||||||
79 | "speculative execution of up to 1 instruction to avoid branching to " | ||||||||
80 | "splitted critical edge"), | ||||||||
81 | cl::init(40), cl::Hidden); | ||||||||
82 | |||||||||
83 | static cl::opt<unsigned> SinkLoadInstsPerBlockThreshold( | ||||||||
84 | "machine-sink-load-instrs-threshold", | ||||||||
85 | cl::desc("Do not try to find alias store for a load if there is a in-path " | ||||||||
86 | "block whose instruction number is higher than this threshold."), | ||||||||
87 | cl::init(2000), cl::Hidden); | ||||||||
88 | |||||||||
89 | static cl::opt<unsigned> SinkLoadBlocksThreshold( | ||||||||
90 | "machine-sink-load-blocks-threshold", | ||||||||
91 | cl::desc("Do not try to find alias store for a load if the block number in " | ||||||||
92 | "the straight line is higher than this threshold."), | ||||||||
93 | cl::init(20), cl::Hidden); | ||||||||
94 | |||||||||
95 | static cl::opt<bool> | ||||||||
96 | SinkInstsIntoLoop("sink-insts-to-avoid-spills", | ||||||||
97 | cl::desc("Sink instructions into loops to avoid " | ||||||||
98 | "register spills"), | ||||||||
99 | cl::init(false), cl::Hidden); | ||||||||
100 | |||||||||
101 | static cl::opt<unsigned> SinkIntoLoopLimit( | ||||||||
102 | "machine-sink-loop-limit", | ||||||||
103 | cl::desc("The maximum number of instructions considered for loop sinking."), | ||||||||
104 | cl::init(50), cl::Hidden); | ||||||||
105 | |||||||||
106 | STATISTIC(NumSunk, "Number of machine instructions sunk")static llvm::Statistic NumSunk = {"machine-sink", "NumSunk", "Number of machine instructions sunk" }; | ||||||||
107 | STATISTIC(NumLoopSunk, "Number of machine instructions sunk into a loop")static llvm::Statistic NumLoopSunk = {"machine-sink", "NumLoopSunk" , "Number of machine instructions sunk into a loop"}; | ||||||||
108 | STATISTIC(NumSplit, "Number of critical edges split")static llvm::Statistic NumSplit = {"machine-sink", "NumSplit" , "Number of critical edges split"}; | ||||||||
109 | STATISTIC(NumCoalesces, "Number of copies coalesced")static llvm::Statistic NumCoalesces = {"machine-sink", "NumCoalesces" , "Number of copies coalesced"}; | ||||||||
110 | STATISTIC(NumPostRACopySink, "Number of copies sunk after RA")static llvm::Statistic NumPostRACopySink = {"machine-sink", "NumPostRACopySink" , "Number of copies sunk after RA"}; | ||||||||
111 | |||||||||
112 | namespace { | ||||||||
113 | |||||||||
114 | class MachineSinking : public MachineFunctionPass { | ||||||||
115 | const TargetInstrInfo *TII; | ||||||||
116 | const TargetRegisterInfo *TRI; | ||||||||
117 | MachineRegisterInfo *MRI; // Machine register information | ||||||||
118 | MachineDominatorTree *DT; // Machine dominator tree | ||||||||
119 | MachinePostDominatorTree *PDT; // Machine post dominator tree | ||||||||
120 | MachineLoopInfo *LI; | ||||||||
121 | MachineBlockFrequencyInfo *MBFI; | ||||||||
122 | const MachineBranchProbabilityInfo *MBPI; | ||||||||
123 | AliasAnalysis *AA; | ||||||||
124 | RegisterClassInfo RegClassInfo; | ||||||||
125 | |||||||||
126 | // Remember which edges have been considered for breaking. | ||||||||
127 | SmallSet<std::pair<MachineBasicBlock*, MachineBasicBlock*>, 8> | ||||||||
128 | CEBCandidates; | ||||||||
129 | // Remember which edges we are about to split. | ||||||||
130 | // This is different from CEBCandidates since those edges | ||||||||
131 | // will be split. | ||||||||
132 | SetVector<std::pair<MachineBasicBlock *, MachineBasicBlock *>> ToSplit; | ||||||||
133 | |||||||||
134 | SparseBitVector<> RegsToClearKillFlags; | ||||||||
135 | |||||||||
136 | using AllSuccsCache = | ||||||||
137 | std::map<MachineBasicBlock *, SmallVector<MachineBasicBlock *, 4>>; | ||||||||
138 | |||||||||
139 | /// DBG_VALUE pointer and flag. The flag is true if this DBG_VALUE is | ||||||||
140 | /// post-dominated by another DBG_VALUE of the same variable location. | ||||||||
141 | /// This is necessary to detect sequences such as: | ||||||||
142 | /// %0 = someinst | ||||||||
143 | /// DBG_VALUE %0, !123, !DIExpression() | ||||||||
144 | /// %1 = anotherinst | ||||||||
145 | /// DBG_VALUE %1, !123, !DIExpression() | ||||||||
146 | /// Where if %0 were to sink, the DBG_VAUE should not sink with it, as that | ||||||||
147 | /// would re-order assignments. | ||||||||
148 | using SeenDbgUser = PointerIntPair<MachineInstr *, 1>; | ||||||||
149 | |||||||||
150 | /// Record of DBG_VALUE uses of vregs in a block, so that we can identify | ||||||||
151 | /// debug instructions to sink. | ||||||||
152 | SmallDenseMap<unsigned, TinyPtrVector<SeenDbgUser>> SeenDbgUsers; | ||||||||
153 | |||||||||
154 | /// Record of debug variables that have had their locations set in the | ||||||||
155 | /// current block. | ||||||||
156 | DenseSet<DebugVariable> SeenDbgVars; | ||||||||
157 | |||||||||
158 | std::map<std::pair<MachineBasicBlock *, MachineBasicBlock *>, bool> | ||||||||
159 | HasStoreCache; | ||||||||
160 | std::map<std::pair<MachineBasicBlock *, MachineBasicBlock *>, | ||||||||
161 | std::vector<MachineInstr *>> | ||||||||
162 | StoreInstrCache; | ||||||||
163 | |||||||||
164 | /// Cached BB's register pressure. | ||||||||
165 | std::map<MachineBasicBlock *, std::vector<unsigned>> CachedRegisterPressure; | ||||||||
166 | |||||||||
167 | public: | ||||||||
168 | static char ID; // Pass identification | ||||||||
169 | |||||||||
170 | MachineSinking() : MachineFunctionPass(ID) { | ||||||||
171 | initializeMachineSinkingPass(*PassRegistry::getPassRegistry()); | ||||||||
172 | } | ||||||||
173 | |||||||||
174 | bool runOnMachineFunction(MachineFunction &MF) override; | ||||||||
175 | |||||||||
176 | void getAnalysisUsage(AnalysisUsage &AU) const override { | ||||||||
177 | MachineFunctionPass::getAnalysisUsage(AU); | ||||||||
178 | AU.addRequired<AAResultsWrapperPass>(); | ||||||||
179 | AU.addRequired<MachineDominatorTree>(); | ||||||||
180 | AU.addRequired<MachinePostDominatorTree>(); | ||||||||
181 | AU.addRequired<MachineLoopInfo>(); | ||||||||
182 | AU.addRequired<MachineBranchProbabilityInfo>(); | ||||||||
183 | AU.addPreserved<MachineLoopInfo>(); | ||||||||
184 | if (UseBlockFreqInfo) | ||||||||
185 | AU.addRequired<MachineBlockFrequencyInfo>(); | ||||||||
186 | } | ||||||||
187 | |||||||||
188 | void releaseMemory() override { | ||||||||
189 | CEBCandidates.clear(); | ||||||||
190 | } | ||||||||
191 | |||||||||
192 | private: | ||||||||
193 | bool ProcessBlock(MachineBasicBlock &MBB); | ||||||||
194 | void ProcessDbgInst(MachineInstr &MI); | ||||||||
195 | bool isWorthBreakingCriticalEdge(MachineInstr &MI, | ||||||||
196 | MachineBasicBlock *From, | ||||||||
197 | MachineBasicBlock *To); | ||||||||
198 | |||||||||
199 | bool hasStoreBetween(MachineBasicBlock *From, MachineBasicBlock *To, | ||||||||
200 | MachineInstr &MI); | ||||||||
201 | |||||||||
202 | /// Postpone the splitting of the given critical | ||||||||
203 | /// edge (\p From, \p To). | ||||||||
204 | /// | ||||||||
205 | /// We do not split the edges on the fly. Indeed, this invalidates | ||||||||
206 | /// the dominance information and thus triggers a lot of updates | ||||||||
207 | /// of that information underneath. | ||||||||
208 | /// Instead, we postpone all the splits after each iteration of | ||||||||
209 | /// the main loop. That way, the information is at least valid | ||||||||
210 | /// for the lifetime of an iteration. | ||||||||
211 | /// | ||||||||
212 | /// \return True if the edge is marked as toSplit, false otherwise. | ||||||||
213 | /// False can be returned if, for instance, this is not profitable. | ||||||||
214 | bool PostponeSplitCriticalEdge(MachineInstr &MI, | ||||||||
215 | MachineBasicBlock *From, | ||||||||
216 | MachineBasicBlock *To, | ||||||||
217 | bool BreakPHIEdge); | ||||||||
218 | bool SinkInstruction(MachineInstr &MI, bool &SawStore, | ||||||||
219 | AllSuccsCache &AllSuccessors); | ||||||||
220 | |||||||||
221 | /// If we sink a COPY inst, some debug users of it's destination may no | ||||||||
222 | /// longer be dominated by the COPY, and will eventually be dropped. | ||||||||
223 | /// This is easily rectified by forwarding the non-dominated debug uses | ||||||||
224 | /// to the copy source. | ||||||||
225 | void SalvageUnsunkDebugUsersOfCopy(MachineInstr &, | ||||||||
226 | MachineBasicBlock *TargetBlock); | ||||||||
227 | bool AllUsesDominatedByBlock(Register Reg, MachineBasicBlock *MBB, | ||||||||
228 | MachineBasicBlock *DefMBB, bool &BreakPHIEdge, | ||||||||
229 | bool &LocalUse) const; | ||||||||
230 | MachineBasicBlock *FindSuccToSinkTo(MachineInstr &MI, MachineBasicBlock *MBB, | ||||||||
231 | bool &BreakPHIEdge, AllSuccsCache &AllSuccessors); | ||||||||
232 | |||||||||
233 | void FindLoopSinkCandidates(MachineLoop *L, MachineBasicBlock *BB, | ||||||||
234 | SmallVectorImpl<MachineInstr *> &Candidates); | ||||||||
235 | bool SinkIntoLoop(MachineLoop *L, MachineInstr &I); | ||||||||
236 | |||||||||
237 | bool isProfitableToSinkTo(Register Reg, MachineInstr &MI, | ||||||||
238 | MachineBasicBlock *MBB, | ||||||||
239 | MachineBasicBlock *SuccToSinkTo, | ||||||||
240 | AllSuccsCache &AllSuccessors); | ||||||||
241 | |||||||||
242 | bool PerformTrivialForwardCoalescing(MachineInstr &MI, | ||||||||
243 | MachineBasicBlock *MBB); | ||||||||
244 | |||||||||
245 | SmallVector<MachineBasicBlock *, 4> & | ||||||||
246 | GetAllSortedSuccessors(MachineInstr &MI, MachineBasicBlock *MBB, | ||||||||
247 | AllSuccsCache &AllSuccessors) const; | ||||||||
248 | |||||||||
249 | std::vector<unsigned> &getBBRegisterPressure(MachineBasicBlock &MBB); | ||||||||
250 | }; | ||||||||
251 | |||||||||
252 | } // end anonymous namespace | ||||||||
253 | |||||||||
254 | char MachineSinking::ID = 0; | ||||||||
255 | |||||||||
256 | char &llvm::MachineSinkingID = MachineSinking::ID; | ||||||||
257 | |||||||||
258 | INITIALIZE_PASS_BEGIN(MachineSinking, DEBUG_TYPE,static void *initializeMachineSinkingPassOnce(PassRegistry & Registry) { | ||||||||
259 | "Machine code sinking", false, false)static void *initializeMachineSinkingPassOnce(PassRegistry & Registry) { | ||||||||
260 | INITIALIZE_PASS_DEPENDENCY(MachineBranchProbabilityInfo)initializeMachineBranchProbabilityInfoPass(Registry); | ||||||||
261 | INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)initializeMachineDominatorTreePass(Registry); | ||||||||
262 | INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)initializeMachineLoopInfoPass(Registry); | ||||||||
263 | INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)initializeAAResultsWrapperPassPass(Registry); | ||||||||
264 | INITIALIZE_PASS_END(MachineSinking, DEBUG_TYPE,PassInfo *PI = new PassInfo( "Machine code sinking", "machine-sink" , &MachineSinking::ID, PassInfo::NormalCtor_t(callDefaultCtor <MachineSinking>), false, false); Registry.registerPass (*PI, true); return PI; } static llvm::once_flag InitializeMachineSinkingPassFlag ; void llvm::initializeMachineSinkingPass(PassRegistry &Registry ) { llvm::call_once(InitializeMachineSinkingPassFlag, initializeMachineSinkingPassOnce , std::ref(Registry)); } | ||||||||
265 | "Machine code sinking", false, false)PassInfo *PI = new PassInfo( "Machine code sinking", "machine-sink" , &MachineSinking::ID, PassInfo::NormalCtor_t(callDefaultCtor <MachineSinking>), false, false); Registry.registerPass (*PI, true); return PI; } static llvm::once_flag InitializeMachineSinkingPassFlag ; void llvm::initializeMachineSinkingPass(PassRegistry &Registry ) { llvm::call_once(InitializeMachineSinkingPassFlag, initializeMachineSinkingPassOnce , std::ref(Registry)); } | ||||||||
266 | |||||||||
267 | bool MachineSinking::PerformTrivialForwardCoalescing(MachineInstr &MI, | ||||||||
268 | MachineBasicBlock *MBB) { | ||||||||
269 | if (!MI.isCopy()) | ||||||||
270 | return false; | ||||||||
271 | |||||||||
272 | Register SrcReg = MI.getOperand(1).getReg(); | ||||||||
273 | Register DstReg = MI.getOperand(0).getReg(); | ||||||||
274 | if (!Register::isVirtualRegister(SrcReg) || | ||||||||
275 | !Register::isVirtualRegister(DstReg) || !MRI->hasOneNonDBGUse(SrcReg)) | ||||||||
276 | return false; | ||||||||
277 | |||||||||
278 | const TargetRegisterClass *SRC = MRI->getRegClass(SrcReg); | ||||||||
279 | const TargetRegisterClass *DRC = MRI->getRegClass(DstReg); | ||||||||
280 | if (SRC != DRC) | ||||||||
281 | return false; | ||||||||
282 | |||||||||
283 | MachineInstr *DefMI = MRI->getVRegDef(SrcReg); | ||||||||
284 | if (DefMI->isCopyLike()) | ||||||||
285 | return false; | ||||||||
286 | LLVM_DEBUG(dbgs() << "Coalescing: " << *DefMI)do { } while (false); | ||||||||
287 | LLVM_DEBUG(dbgs() << "*** to: " << MI)do { } while (false); | ||||||||
288 | MRI->replaceRegWith(DstReg, SrcReg); | ||||||||
289 | MI.eraseFromParent(); | ||||||||
290 | |||||||||
291 | // Conservatively, clear any kill flags, since it's possible that they are no | ||||||||
292 | // longer correct. | ||||||||
293 | MRI->clearKillFlags(SrcReg); | ||||||||
294 | |||||||||
295 | ++NumCoalesces; | ||||||||
296 | return true; | ||||||||
297 | } | ||||||||
298 | |||||||||
299 | /// AllUsesDominatedByBlock - Return true if all uses of the specified register | ||||||||
300 | /// occur in blocks dominated by the specified block. If any use is in the | ||||||||
301 | /// definition block, then return false since it is never legal to move def | ||||||||
302 | /// after uses. | ||||||||
303 | bool MachineSinking::AllUsesDominatedByBlock(Register Reg, | ||||||||
304 | MachineBasicBlock *MBB, | ||||||||
305 | MachineBasicBlock *DefMBB, | ||||||||
306 | bool &BreakPHIEdge, | ||||||||
307 | bool &LocalUse) const { | ||||||||
308 | assert(Register::isVirtualRegister(Reg) && "Only makes sense for vregs")((void)0); | ||||||||
309 | |||||||||
310 | // Ignore debug uses because debug info doesn't affect the code. | ||||||||
311 | if (MRI->use_nodbg_empty(Reg)) | ||||||||
312 | return true; | ||||||||
313 | |||||||||
314 | // BreakPHIEdge is true if all the uses are in the successor MBB being sunken | ||||||||
315 | // into and they are all PHI nodes. In this case, machine-sink must break | ||||||||
316 | // the critical edge first. e.g. | ||||||||
317 | // | ||||||||
318 | // %bb.1: | ||||||||
319 | // Predecessors according to CFG: %bb.0 | ||||||||
320 | // ... | ||||||||
321 | // %def = DEC64_32r %x, implicit-def dead %eflags | ||||||||
322 | // ... | ||||||||
323 | // JE_4 <%bb.37>, implicit %eflags | ||||||||
324 | // Successors according to CFG: %bb.37 %bb.2 | ||||||||
325 | // | ||||||||
326 | // %bb.2: | ||||||||
327 | // %p = PHI %y, %bb.0, %def, %bb.1 | ||||||||
328 | if (all_of(MRI->use_nodbg_operands(Reg), [&](MachineOperand &MO) { | ||||||||
329 | MachineInstr *UseInst = MO.getParent(); | ||||||||
330 | unsigned OpNo = UseInst->getOperandNo(&MO); | ||||||||
331 | MachineBasicBlock *UseBlock = UseInst->getParent(); | ||||||||
332 | return UseBlock == MBB && UseInst->isPHI() && | ||||||||
333 | UseInst->getOperand(OpNo + 1).getMBB() == DefMBB; | ||||||||
334 | })) { | ||||||||
335 | BreakPHIEdge = true; | ||||||||
336 | return true; | ||||||||
337 | } | ||||||||
338 | |||||||||
339 | for (MachineOperand &MO : MRI->use_nodbg_operands(Reg)) { | ||||||||
340 | // Determine the block of the use. | ||||||||
341 | MachineInstr *UseInst = MO.getParent(); | ||||||||
342 | unsigned OpNo = &MO - &UseInst->getOperand(0); | ||||||||
343 | MachineBasicBlock *UseBlock = UseInst->getParent(); | ||||||||
344 | if (UseInst->isPHI()) { | ||||||||
345 | // PHI nodes use the operand in the predecessor block, not the block with | ||||||||
346 | // the PHI. | ||||||||
347 | UseBlock = UseInst->getOperand(OpNo+1).getMBB(); | ||||||||
348 | } else if (UseBlock == DefMBB) { | ||||||||
349 | LocalUse = true; | ||||||||
350 | return false; | ||||||||
351 | } | ||||||||
352 | |||||||||
353 | // Check that it dominates. | ||||||||
354 | if (!DT->dominates(MBB, UseBlock)) | ||||||||
355 | return false; | ||||||||
356 | } | ||||||||
357 | |||||||||
358 | return true; | ||||||||
359 | } | ||||||||
360 | |||||||||
361 | /// Return true if this machine instruction loads from global offset table or | ||||||||
362 | /// constant pool. | ||||||||
363 | static bool mayLoadFromGOTOrConstantPool(MachineInstr &MI) { | ||||||||
364 | assert(MI.mayLoad() && "Expected MI that loads!")((void)0); | ||||||||
365 | |||||||||
366 | // If we lost memory operands, conservatively assume that the instruction | ||||||||
367 | // reads from everything.. | ||||||||
368 | if (MI.memoperands_empty()) | ||||||||
369 | return true; | ||||||||
370 | |||||||||
371 | for (MachineMemOperand *MemOp : MI.memoperands()) | ||||||||
372 | if (const PseudoSourceValue *PSV = MemOp->getPseudoValue()) | ||||||||
373 | if (PSV->isGOT() || PSV->isConstantPool()) | ||||||||
374 | return true; | ||||||||
375 | |||||||||
376 | return false; | ||||||||
377 | } | ||||||||
378 | |||||||||
379 | void MachineSinking::FindLoopSinkCandidates(MachineLoop *L, MachineBasicBlock *BB, | ||||||||
380 | SmallVectorImpl<MachineInstr *> &Candidates) { | ||||||||
381 | for (auto &MI : *BB) { | ||||||||
382 | LLVM_DEBUG(dbgs() << "LoopSink: Analysing candidate: " << MI)do { } while (false); | ||||||||
383 | if (!TII->shouldSink(MI)) { | ||||||||
384 | LLVM_DEBUG(dbgs() << "LoopSink: Instruction not a candidate for this "do { } while (false) | ||||||||
385 | "target\n")do { } while (false); | ||||||||
386 | continue; | ||||||||
387 | } | ||||||||
388 | if (!L->isLoopInvariant(MI)) { | ||||||||
389 | LLVM_DEBUG(dbgs() << "LoopSink: Instruction is not loop invariant\n")do { } while (false); | ||||||||
390 | continue; | ||||||||
391 | } | ||||||||
392 | bool DontMoveAcrossStore = true; | ||||||||
393 | if (!MI.isSafeToMove(AA, DontMoveAcrossStore)) { | ||||||||
394 | LLVM_DEBUG(dbgs() << "LoopSink: Instruction not safe to move.\n")do { } while (false); | ||||||||
395 | continue; | ||||||||
396 | } | ||||||||
397 | if (MI.mayLoad() && !mayLoadFromGOTOrConstantPool(MI)) { | ||||||||
398 | LLVM_DEBUG(dbgs() << "LoopSink: Dont sink GOT or constant pool loads\n")do { } while (false); | ||||||||
399 | continue; | ||||||||
400 | } | ||||||||
401 | if (MI.isConvergent()) | ||||||||
402 | continue; | ||||||||
403 | |||||||||
404 | const MachineOperand &MO = MI.getOperand(0); | ||||||||
405 | if (!MO.isReg() || !MO.getReg() || !MO.isDef()) | ||||||||
406 | continue; | ||||||||
407 | if (!MRI->hasOneDef(MO.getReg())) | ||||||||
408 | continue; | ||||||||
409 | |||||||||
410 | LLVM_DEBUG(dbgs() << "LoopSink: Instruction added as candidate.\n")do { } while (false); | ||||||||
411 | Candidates.push_back(&MI); | ||||||||
412 | } | ||||||||
413 | } | ||||||||
414 | |||||||||
415 | bool MachineSinking::runOnMachineFunction(MachineFunction &MF) { | ||||||||
416 | if (skipFunction(MF.getFunction())) | ||||||||
| |||||||||
417 | return false; | ||||||||
418 | |||||||||
419 | LLVM_DEBUG(dbgs() << "******** Machine Sinking ********\n")do { } while (false); | ||||||||
420 | |||||||||
421 | TII = MF.getSubtarget().getInstrInfo(); | ||||||||
422 | TRI = MF.getSubtarget().getRegisterInfo(); | ||||||||
423 | MRI = &MF.getRegInfo(); | ||||||||
424 | DT = &getAnalysis<MachineDominatorTree>(); | ||||||||
425 | PDT = &getAnalysis<MachinePostDominatorTree>(); | ||||||||
426 | LI = &getAnalysis<MachineLoopInfo>(); | ||||||||
427 | MBFI = UseBlockFreqInfo ? &getAnalysis<MachineBlockFrequencyInfo>() : nullptr; | ||||||||
428 | MBPI = &getAnalysis<MachineBranchProbabilityInfo>(); | ||||||||
429 | AA = &getAnalysis<AAResultsWrapperPass>().getAAResults(); | ||||||||
430 | RegClassInfo.runOnMachineFunction(MF); | ||||||||
431 | |||||||||
432 | bool EverMadeChange = false; | ||||||||
433 | |||||||||
434 | while (true) { | ||||||||
435 | bool MadeChange = false; | ||||||||
436 | |||||||||
437 | // Process all basic blocks. | ||||||||
438 | CEBCandidates.clear(); | ||||||||
439 | ToSplit.clear(); | ||||||||
440 | for (auto &MBB: MF) | ||||||||
441 | MadeChange |= ProcessBlock(MBB); | ||||||||
442 | |||||||||
443 | // If we have anything we marked as toSplit, split it now. | ||||||||
444 | for (auto &Pair : ToSplit) { | ||||||||
445 | auto NewSucc = Pair.first->SplitCriticalEdge(Pair.second, *this); | ||||||||
446 | if (NewSucc != nullptr) { | ||||||||
447 | LLVM_DEBUG(dbgs() << " *** Splitting critical edge: "do { } while (false) | ||||||||
448 | << printMBBReference(*Pair.first) << " -- "do { } while (false) | ||||||||
449 | << printMBBReference(*NewSucc) << " -- "do { } while (false) | ||||||||
450 | << printMBBReference(*Pair.second) << '\n')do { } while (false); | ||||||||
451 | if (MBFI) | ||||||||
452 | MBFI->onEdgeSplit(*Pair.first, *NewSucc, *MBPI); | ||||||||
453 | |||||||||
454 | MadeChange = true; | ||||||||
455 | ++NumSplit; | ||||||||
456 | } else | ||||||||
457 | LLVM_DEBUG(dbgs() << " *** Not legal to break critical edge\n")do { } while (false); | ||||||||
458 | } | ||||||||
459 | // If this iteration over the code changed anything, keep iterating. | ||||||||
460 | if (!MadeChange
| ||||||||
461 | EverMadeChange = true; | ||||||||
462 | } | ||||||||
463 | |||||||||
464 | if (SinkInstsIntoLoop) { | ||||||||
465 | SmallVector<MachineLoop *, 8> Loops(LI->begin(), LI->end()); | ||||||||
466 | for (auto *L : Loops) { | ||||||||
467 | MachineBasicBlock *Preheader = LI->findLoopPreheader(L); | ||||||||
468 | if (!Preheader) { | ||||||||
469 | LLVM_DEBUG(dbgs() << "LoopSink: Can't find preheader\n")do { } while (false); | ||||||||
470 | continue; | ||||||||
471 | } | ||||||||
472 | SmallVector<MachineInstr *, 8> Candidates; | ||||||||
473 | FindLoopSinkCandidates(L, Preheader, Candidates); | ||||||||
474 | |||||||||
475 | // Walk the candidates in reverse order so that we start with the use | ||||||||
476 | // of a def-use chain, if there is any. | ||||||||
477 | // TODO: Sort the candidates using a cost-model. | ||||||||
478 | unsigned i = 0; | ||||||||
479 | for (auto It = Candidates.rbegin(); It != Candidates.rend(); ++It) { | ||||||||
480 | if (i++ == SinkIntoLoopLimit) { | ||||||||
481 | LLVM_DEBUG(dbgs() << "LoopSink: Limit reached of instructions to "do { } while (false) | ||||||||
482 | "be analysed.")do { } while (false); | ||||||||
483 | break; | ||||||||
484 | } | ||||||||
485 | |||||||||
486 | MachineInstr *I = *It; | ||||||||
487 | if (!SinkIntoLoop(L, *I)) | ||||||||
488 | break; | ||||||||
489 | EverMadeChange = true; | ||||||||
490 | ++NumLoopSunk; | ||||||||
491 | } | ||||||||
492 | } | ||||||||
493 | } | ||||||||
494 | |||||||||
495 | HasStoreCache.clear(); | ||||||||
496 | StoreInstrCache.clear(); | ||||||||
497 | |||||||||
498 | // Now clear any kill flags for recorded registers. | ||||||||
499 | for (auto I : RegsToClearKillFlags) | ||||||||
500 | MRI->clearKillFlags(I); | ||||||||
501 | RegsToClearKillFlags.clear(); | ||||||||
502 | |||||||||
503 | return EverMadeChange; | ||||||||
504 | } | ||||||||
505 | |||||||||
506 | bool MachineSinking::ProcessBlock(MachineBasicBlock &MBB) { | ||||||||
507 | // Can't sink anything out of a block that has less than two successors. | ||||||||
508 | if (MBB.succ_size() <= 1 || MBB.empty()) return false; | ||||||||
509 | |||||||||
510 | // Don't bother sinking code out of unreachable blocks. In addition to being | ||||||||
511 | // unprofitable, it can also lead to infinite looping, because in an | ||||||||
512 | // unreachable loop there may be nowhere to stop. | ||||||||
513 | if (!DT->isReachableFromEntry(&MBB)) return false; | ||||||||
514 | |||||||||
515 | bool MadeChange = false; | ||||||||
516 | |||||||||
517 | // Cache all successors, sorted by frequency info and loop depth. | ||||||||
518 | AllSuccsCache AllSuccessors; | ||||||||
519 | |||||||||
520 | // Walk the basic block bottom-up. Remember if we saw a store. | ||||||||
521 | MachineBasicBlock::iterator I = MBB.end(); | ||||||||
522 | --I; | ||||||||
523 | bool ProcessedBegin, SawStore = false; | ||||||||
524 | do { | ||||||||
525 | MachineInstr &MI = *I; // The instruction to sink. | ||||||||
526 | |||||||||
527 | // Predecrement I (if it's not begin) so that it isn't invalidated by | ||||||||
528 | // sinking. | ||||||||
529 | ProcessedBegin = I == MBB.begin(); | ||||||||
530 | if (!ProcessedBegin) | ||||||||
531 | --I; | ||||||||
532 | |||||||||
533 | if (MI.isDebugOrPseudoInstr()) { | ||||||||
534 | if (MI.isDebugValue()) | ||||||||
535 | ProcessDbgInst(MI); | ||||||||
536 | continue; | ||||||||
537 | } | ||||||||
538 | |||||||||
539 | bool Joined = PerformTrivialForwardCoalescing(MI, &MBB); | ||||||||
540 | if (Joined) { | ||||||||
541 | MadeChange = true; | ||||||||
542 | continue; | ||||||||
543 | } | ||||||||
544 | |||||||||
545 | if (SinkInstruction(MI, SawStore, AllSuccessors)) { | ||||||||
546 | ++NumSunk; | ||||||||
547 | MadeChange = true; | ||||||||
548 | } | ||||||||
549 | |||||||||
550 | // If we just processed the first instruction in the block, we're done. | ||||||||
551 | } while (!ProcessedBegin); | ||||||||
552 | |||||||||
553 | SeenDbgUsers.clear(); | ||||||||
554 | SeenDbgVars.clear(); | ||||||||
555 | // recalculate the bb register pressure after sinking one BB. | ||||||||
556 | CachedRegisterPressure.clear(); | ||||||||
557 | |||||||||
558 | return MadeChange; | ||||||||
559 | } | ||||||||
560 | |||||||||
561 | void MachineSinking::ProcessDbgInst(MachineInstr &MI) { | ||||||||
562 | // When we see DBG_VALUEs for registers, record any vreg it reads, so that | ||||||||
563 | // we know what to sink if the vreg def sinks. | ||||||||
564 | assert(MI.isDebugValue() && "Expected DBG_VALUE for processing")((void)0); | ||||||||
565 | |||||||||
566 | DebugVariable Var(MI.getDebugVariable(), MI.getDebugExpression(), | ||||||||
567 | MI.getDebugLoc()->getInlinedAt()); | ||||||||
568 | bool SeenBefore = SeenDbgVars.contains(Var); | ||||||||
569 | |||||||||
570 | for (MachineOperand &MO : MI.debug_operands()) { | ||||||||
571 | if (MO.isReg() && MO.getReg().isVirtual()) | ||||||||
572 | SeenDbgUsers[MO.getReg()].push_back(SeenDbgUser(&MI, SeenBefore)); | ||||||||
573 | } | ||||||||
574 | |||||||||
575 | // Record the variable for any DBG_VALUE, to avoid re-ordering any of them. | ||||||||
576 | SeenDbgVars.insert(Var); | ||||||||
577 | } | ||||||||
578 | |||||||||
579 | bool MachineSinking::isWorthBreakingCriticalEdge(MachineInstr &MI, | ||||||||
580 | MachineBasicBlock *From, | ||||||||
581 | MachineBasicBlock *To) { | ||||||||
582 | // FIXME: Need much better heuristics. | ||||||||
583 | |||||||||
584 | // If the pass has already considered breaking this edge (during this pass | ||||||||
585 | // through the function), then let's go ahead and break it. This means | ||||||||
586 | // sinking multiple "cheap" instructions into the same block. | ||||||||
587 | if (!CEBCandidates.insert(std::make_pair(From, To)).second) | ||||||||
588 | return true; | ||||||||
589 | |||||||||
590 | if (!MI.isCopy() && !TII->isAsCheapAsAMove(MI)) | ||||||||
591 | return true; | ||||||||
592 | |||||||||
593 | if (From->isSuccessor(To) && MBPI->getEdgeProbability(From, To) <= | ||||||||
594 | BranchProbability(SplitEdgeProbabilityThreshold, 100)) | ||||||||
595 | return true; | ||||||||
596 | |||||||||
597 | // MI is cheap, we probably don't want to break the critical edge for it. | ||||||||
598 | // However, if this would allow some definitions of its source operands | ||||||||
599 | // to be sunk then it's probably worth it. | ||||||||
600 | for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) { | ||||||||
601 | const MachineOperand &MO = MI.getOperand(i); | ||||||||
602 | if (!MO.isReg() || !MO.isUse()) | ||||||||
603 | continue; | ||||||||
604 | Register Reg = MO.getReg(); | ||||||||
605 | if (Reg == 0) | ||||||||
606 | continue; | ||||||||
607 | |||||||||
608 | // We don't move live definitions of physical registers, | ||||||||
609 | // so sinking their uses won't enable any opportunities. | ||||||||
610 | if (Register::isPhysicalRegister(Reg)) | ||||||||
611 | continue; | ||||||||
612 | |||||||||
613 | // If this instruction is the only user of a virtual register, | ||||||||
614 | // check if breaking the edge will enable sinking | ||||||||
615 | // both this instruction and the defining instruction. | ||||||||
616 | if (MRI->hasOneNonDBGUse(Reg)) { | ||||||||
617 | // If the definition resides in same MBB, | ||||||||
618 | // claim it's likely we can sink these together. | ||||||||
619 | // If definition resides elsewhere, we aren't | ||||||||
620 | // blocking it from being sunk so don't break the edge. | ||||||||
621 | MachineInstr *DefMI = MRI->getVRegDef(Reg); | ||||||||
622 | if (DefMI->getParent() == MI.getParent()) | ||||||||
623 | return true; | ||||||||
624 | } | ||||||||
625 | } | ||||||||
626 | |||||||||
627 | return false; | ||||||||
628 | } | ||||||||
629 | |||||||||
630 | bool MachineSinking::PostponeSplitCriticalEdge(MachineInstr &MI, | ||||||||
631 | MachineBasicBlock *FromBB, | ||||||||
632 | MachineBasicBlock *ToBB, | ||||||||
633 | bool BreakPHIEdge) { | ||||||||
634 | if (!isWorthBreakingCriticalEdge(MI, FromBB, ToBB)) | ||||||||
635 | return false; | ||||||||
636 | |||||||||
637 | // Avoid breaking back edge. From == To means backedge for single BB loop. | ||||||||
638 | if (!SplitEdges || FromBB == ToBB) | ||||||||
639 | return false; | ||||||||
640 | |||||||||
641 | // Check for backedges of more "complex" loops. | ||||||||
642 | if (LI->getLoopFor(FromBB) == LI->getLoopFor(ToBB) && | ||||||||
643 | LI->isLoopHeader(ToBB)) | ||||||||
644 | return false; | ||||||||
645 | |||||||||
646 | // It's not always legal to break critical edges and sink the computation | ||||||||
647 | // to the edge. | ||||||||
648 | // | ||||||||
649 | // %bb.1: | ||||||||
650 | // v1024 | ||||||||
651 | // Beq %bb.3 | ||||||||
652 | // <fallthrough> | ||||||||
653 | // %bb.2: | ||||||||
654 | // ... no uses of v1024 | ||||||||
655 | // <fallthrough> | ||||||||
656 | // %bb.3: | ||||||||
657 | // ... | ||||||||
658 | // = v1024 | ||||||||
659 | // | ||||||||
660 | // If %bb.1 -> %bb.3 edge is broken and computation of v1024 is inserted: | ||||||||
661 | // | ||||||||
662 | // %bb.1: | ||||||||
663 | // ... | ||||||||
664 | // Bne %bb.2 | ||||||||
665 | // %bb.4: | ||||||||
666 | // v1024 = | ||||||||
667 | // B %bb.3 | ||||||||
668 | // %bb.2: | ||||||||
669 | // ... no uses of v1024 | ||||||||
670 | // <fallthrough> | ||||||||
671 | // %bb.3: | ||||||||
672 | // ... | ||||||||
673 | // = v1024 | ||||||||
674 | // | ||||||||
675 | // This is incorrect since v1024 is not computed along the %bb.1->%bb.2->%bb.3 | ||||||||
676 | // flow. We need to ensure the new basic block where the computation is | ||||||||
677 | // sunk to dominates all the uses. | ||||||||
678 | // It's only legal to break critical edge and sink the computation to the | ||||||||
679 | // new block if all the predecessors of "To", except for "From", are | ||||||||
680 | // not dominated by "From". Given SSA property, this means these | ||||||||
681 | // predecessors are dominated by "To". | ||||||||
682 | // | ||||||||
683 | // There is no need to do this check if all the uses are PHI nodes. PHI | ||||||||
684 | // sources are only defined on the specific predecessor edges. | ||||||||
685 | if (!BreakPHIEdge) { | ||||||||
686 | for (MachineBasicBlock::pred_iterator PI = ToBB->pred_begin(), | ||||||||
687 | E = ToBB->pred_end(); PI != E; ++PI) { | ||||||||
688 | if (*PI == FromBB) | ||||||||
689 | continue; | ||||||||
690 | if (!DT->dominates(ToBB, *PI)) | ||||||||
691 | return false; | ||||||||
692 | } | ||||||||
693 | } | ||||||||
694 | |||||||||
695 | ToSplit.insert(std::make_pair(FromBB, ToBB)); | ||||||||
696 | |||||||||
697 | return true; | ||||||||
698 | } | ||||||||
699 | |||||||||
700 | std::vector<unsigned> & | ||||||||
701 | MachineSinking::getBBRegisterPressure(MachineBasicBlock &MBB) { | ||||||||
702 | // Currently to save compiling time, MBB's register pressure will not change | ||||||||
703 | // in one ProcessBlock iteration because of CachedRegisterPressure. but MBB's | ||||||||
704 | // register pressure is changed after sinking any instructions into it. | ||||||||
705 | // FIXME: need a accurate and cheap register pressure estiminate model here. | ||||||||
706 | auto RP = CachedRegisterPressure.find(&MBB); | ||||||||
707 | if (RP != CachedRegisterPressure.end()) | ||||||||
708 | return RP->second; | ||||||||
709 | |||||||||
710 | RegionPressure Pressure; | ||||||||
711 | RegPressureTracker RPTracker(Pressure); | ||||||||
712 | |||||||||
713 | // Initialize the register pressure tracker. | ||||||||
714 | RPTracker.init(MBB.getParent(), &RegClassInfo, nullptr, &MBB, MBB.end(), | ||||||||
715 | /*TrackLaneMasks*/ false, /*TrackUntiedDefs=*/true); | ||||||||
716 | |||||||||
717 | for (MachineBasicBlock::iterator MII = MBB.instr_end(), | ||||||||
718 | MIE = MBB.instr_begin(); | ||||||||
719 | MII != MIE; --MII) { | ||||||||
720 | MachineInstr &MI = *std::prev(MII); | ||||||||
721 | if (MI.isDebugInstr() || MI.isPseudoProbe()) | ||||||||
722 | continue; | ||||||||
723 | RegisterOperands RegOpers; | ||||||||
724 | RegOpers.collect(MI, *TRI, *MRI, false, false); | ||||||||
725 | RPTracker.recedeSkipDebugValues(); | ||||||||
726 | assert(&*RPTracker.getPos() == &MI && "RPTracker sync error!")((void)0); | ||||||||
727 | RPTracker.recede(RegOpers); | ||||||||
728 | } | ||||||||
729 | |||||||||
730 | RPTracker.closeRegion(); | ||||||||
731 | auto It = CachedRegisterPressure.insert( | ||||||||
732 | std::make_pair(&MBB, RPTracker.getPressure().MaxSetPressure)); | ||||||||
733 | return It.first->second; | ||||||||
734 | } | ||||||||
735 | |||||||||
736 | /// isProfitableToSinkTo - Return true if it is profitable to sink MI. | ||||||||
737 | bool MachineSinking::isProfitableToSinkTo(Register Reg, MachineInstr &MI, | ||||||||
738 | MachineBasicBlock *MBB, | ||||||||
739 | MachineBasicBlock *SuccToSinkTo, | ||||||||
740 | AllSuccsCache &AllSuccessors) { | ||||||||
741 | assert (SuccToSinkTo && "Invalid SinkTo Candidate BB")((void)0); | ||||||||
742 | |||||||||
743 | if (MBB == SuccToSinkTo) | ||||||||
744 | return false; | ||||||||
745 | |||||||||
746 | // It is profitable if SuccToSinkTo does not post dominate current block. | ||||||||
747 | if (!PDT->dominates(SuccToSinkTo, MBB)) | ||||||||
748 | return true; | ||||||||
749 | |||||||||
750 | // It is profitable to sink an instruction from a deeper loop to a shallower | ||||||||
751 | // loop, even if the latter post-dominates the former (PR21115). | ||||||||
752 | if (LI->getLoopDepth(MBB) > LI->getLoopDepth(SuccToSinkTo)) | ||||||||
753 | return true; | ||||||||
754 | |||||||||
755 | // Check if only use in post dominated block is PHI instruction. | ||||||||
756 | bool NonPHIUse = false; | ||||||||
757 | for (MachineInstr &UseInst : MRI->use_nodbg_instructions(Reg)) { | ||||||||
758 | MachineBasicBlock *UseBlock = UseInst.getParent(); | ||||||||
759 | if (UseBlock == SuccToSinkTo && !UseInst.isPHI()) | ||||||||
760 | NonPHIUse = true; | ||||||||
761 | } | ||||||||
762 | if (!NonPHIUse) | ||||||||
763 | return true; | ||||||||
764 | |||||||||
765 | // If SuccToSinkTo post dominates then also it may be profitable if MI | ||||||||
766 | // can further profitably sinked into another block in next round. | ||||||||
767 | bool BreakPHIEdge = false; | ||||||||
768 | // FIXME - If finding successor is compile time expensive then cache results. | ||||||||
769 | if (MachineBasicBlock *MBB2 = | ||||||||
770 | FindSuccToSinkTo(MI, SuccToSinkTo, BreakPHIEdge, AllSuccessors)) | ||||||||
771 | return isProfitableToSinkTo(Reg, MI, SuccToSinkTo, MBB2, AllSuccessors); | ||||||||
772 | |||||||||
773 | MachineLoop *ML = LI->getLoopFor(MBB); | ||||||||
774 | |||||||||
775 | // If the instruction is not inside a loop, it is not profitable to sink MI to | ||||||||
776 | // a post dominate block SuccToSinkTo. | ||||||||
777 | if (!ML) | ||||||||
778 | return false; | ||||||||
779 | |||||||||
780 | auto isRegisterPressureSetExceedLimit = [&](const TargetRegisterClass *RC) { | ||||||||
781 | unsigned Weight = TRI->getRegClassWeight(RC).RegWeight; | ||||||||
782 | const int *PS = TRI->getRegClassPressureSets(RC); | ||||||||
783 | // Get register pressure for block SuccToSinkTo. | ||||||||
784 | std::vector<unsigned> BBRegisterPressure = | ||||||||
785 | getBBRegisterPressure(*SuccToSinkTo); | ||||||||
786 | for (; *PS != -1; PS++) | ||||||||
787 | // check if any register pressure set exceeds limit in block SuccToSinkTo | ||||||||
788 | // after sinking. | ||||||||
789 | if (Weight + BBRegisterPressure[*PS] >= | ||||||||
790 | TRI->getRegPressureSetLimit(*MBB->getParent(), *PS)) | ||||||||
791 | return true; | ||||||||
792 | return false; | ||||||||
793 | }; | ||||||||
794 | |||||||||
795 | // If this instruction is inside a loop and sinking this instruction can make | ||||||||
796 | // more registers live range shorten, it is still prifitable. | ||||||||
797 | for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) { | ||||||||
798 | const MachineOperand &MO = MI.getOperand(i); | ||||||||
799 | // Ignore non-register operands. | ||||||||
800 | if (!MO.isReg()) | ||||||||
801 | continue; | ||||||||
802 | Register Reg = MO.getReg(); | ||||||||
803 | if (Reg == 0) | ||||||||
804 | continue; | ||||||||
805 | |||||||||
806 | // Don't handle physical register. | ||||||||
807 | if (Register::isPhysicalRegister(Reg)) | ||||||||
808 | return false; | ||||||||
809 | |||||||||
810 | // Users for the defs are all dominated by SuccToSinkTo. | ||||||||
811 | if (MO.isDef()) { | ||||||||
812 | // This def register's live range is shortened after sinking. | ||||||||
813 | bool LocalUse = false; | ||||||||
814 | if (!AllUsesDominatedByBlock(Reg, SuccToSinkTo, MBB, BreakPHIEdge, | ||||||||
815 | LocalUse)) | ||||||||
816 | return false; | ||||||||
817 | } else { | ||||||||
818 | MachineInstr *DefMI = MRI->getVRegDef(Reg); | ||||||||
819 | // DefMI is defined outside of loop. There should be no live range | ||||||||
820 | // impact for this operand. Defination outside of loop means: | ||||||||
821 | // 1: defination is outside of loop. | ||||||||
822 | // 2: defination is in this loop, but it is a PHI in the loop header. | ||||||||
823 | if (LI->getLoopFor(DefMI->getParent()) != ML || | ||||||||
824 | (DefMI->isPHI() && LI->isLoopHeader(DefMI->getParent()))) | ||||||||
825 | continue; | ||||||||
826 | // The DefMI is defined inside the loop. | ||||||||
827 | // If sinking this operand makes some register pressure set exceed limit, | ||||||||
828 | // it is not profitable. | ||||||||
829 | if (isRegisterPressureSetExceedLimit(MRI->getRegClass(Reg))) { | ||||||||
830 | LLVM_DEBUG(dbgs() << "register pressure exceed limit, not profitable.")do { } while (false); | ||||||||
831 | return false; | ||||||||
832 | } | ||||||||
833 | } | ||||||||
834 | } | ||||||||
835 | |||||||||
836 | // If MI is in loop and all its operands are alive across the whole loop or if | ||||||||
837 | // no operand sinking make register pressure set exceed limit, it is | ||||||||
838 | // profitable to sink MI. | ||||||||
839 | return true; | ||||||||
840 | } | ||||||||
841 | |||||||||
842 | /// Get the sorted sequence of successors for this MachineBasicBlock, possibly | ||||||||
843 | /// computing it if it was not already cached. | ||||||||
844 | SmallVector<MachineBasicBlock *, 4> & | ||||||||
845 | MachineSinking::GetAllSortedSuccessors(MachineInstr &MI, MachineBasicBlock *MBB, | ||||||||
846 | AllSuccsCache &AllSuccessors) const { | ||||||||
847 | // Do we have the sorted successors in cache ? | ||||||||
848 | auto Succs = AllSuccessors.find(MBB); | ||||||||
849 | if (Succs != AllSuccessors.end()) | ||||||||
850 | return Succs->second; | ||||||||
851 | |||||||||
852 | SmallVector<MachineBasicBlock *, 4> AllSuccs(MBB->successors()); | ||||||||
853 | |||||||||
854 | // Handle cases where sinking can happen but where the sink point isn't a | ||||||||
855 | // successor. For example: | ||||||||
856 | // | ||||||||
857 | // x = computation | ||||||||
858 | // if () {} else {} | ||||||||
859 | // use x | ||||||||
860 | // | ||||||||
861 | for (MachineDomTreeNode *DTChild : DT->getNode(MBB)->children()) { | ||||||||
862 | // DomTree children of MBB that have MBB as immediate dominator are added. | ||||||||
863 | if (DTChild->getIDom()->getBlock() == MI.getParent() && | ||||||||
864 | // Skip MBBs already added to the AllSuccs vector above. | ||||||||
865 | !MBB->isSuccessor(DTChild->getBlock())) | ||||||||
866 | AllSuccs.push_back(DTChild->getBlock()); | ||||||||
867 | } | ||||||||
868 | |||||||||
869 | // Sort Successors according to their loop depth or block frequency info. | ||||||||
870 | llvm::stable_sort( | ||||||||
871 | AllSuccs, [this](const MachineBasicBlock *L, const MachineBasicBlock *R) { | ||||||||
872 | uint64_t LHSFreq = MBFI ? MBFI->getBlockFreq(L).getFrequency() : 0; | ||||||||
873 | uint64_t RHSFreq = MBFI ? MBFI->getBlockFreq(R).getFrequency() : 0; | ||||||||
874 | bool HasBlockFreq = LHSFreq != 0 && RHSFreq != 0; | ||||||||
875 | return HasBlockFreq ? LHSFreq < RHSFreq | ||||||||
876 | : LI->getLoopDepth(L) < LI->getLoopDepth(R); | ||||||||
877 | }); | ||||||||
878 | |||||||||
879 | auto it = AllSuccessors.insert(std::make_pair(MBB, AllSuccs)); | ||||||||
880 | |||||||||
881 | return it.first->second; | ||||||||
882 | } | ||||||||
883 | |||||||||
884 | /// FindSuccToSinkTo - Find a successor to sink this instruction to. | ||||||||
885 | MachineBasicBlock * | ||||||||
886 | MachineSinking::FindSuccToSinkTo(MachineInstr &MI, MachineBasicBlock *MBB, | ||||||||
887 | bool &BreakPHIEdge, | ||||||||
888 | AllSuccsCache &AllSuccessors) { | ||||||||
889 | assert (MBB && "Invalid MachineBasicBlock!")((void)0); | ||||||||
890 | |||||||||
891 | // Loop over all the operands of the specified instruction. If there is | ||||||||
892 | // anything we can't handle, bail out. | ||||||||
893 | |||||||||
894 | // SuccToSinkTo - This is the successor to sink this instruction to, once we | ||||||||
895 | // decide. | ||||||||
896 | MachineBasicBlock *SuccToSinkTo = nullptr; | ||||||||
897 | for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) { | ||||||||
898 | const MachineOperand &MO = MI.getOperand(i); | ||||||||
899 | if (!MO.isReg()) continue; // Ignore non-register operands. | ||||||||
900 | |||||||||
901 | Register Reg = MO.getReg(); | ||||||||
902 | if (Reg == 0) continue; | ||||||||
903 | |||||||||
904 | if (Register::isPhysicalRegister(Reg)) { | ||||||||
905 | if (MO.isUse()) { | ||||||||
906 | // If the physreg has no defs anywhere, it's just an ambient register | ||||||||
907 | // and we can freely move its uses. Alternatively, if it's allocatable, | ||||||||
908 | // it could get allocated to something with a def during allocation. | ||||||||
909 | if (!MRI->isConstantPhysReg(Reg)) | ||||||||
910 | return nullptr; | ||||||||
911 | } else if (!MO.isDead()) { | ||||||||
912 | // A def that isn't dead. We can't move it. | ||||||||
913 | return nullptr; | ||||||||
914 | } | ||||||||
915 | } else { | ||||||||
916 | // Virtual register uses are always safe to sink. | ||||||||
917 | if (MO.isUse()) continue; | ||||||||
918 | |||||||||
919 | // If it's not safe to move defs of the register class, then abort. | ||||||||
920 | if (!TII->isSafeToMoveRegClassDefs(MRI->getRegClass(Reg))) | ||||||||
921 | return nullptr; | ||||||||
922 | |||||||||
923 | // Virtual register defs can only be sunk if all their uses are in blocks | ||||||||
924 | // dominated by one of the successors. | ||||||||
925 | if (SuccToSinkTo) { | ||||||||
926 | // If a previous operand picked a block to sink to, then this operand | ||||||||
927 | // must be sinkable to the same block. | ||||||||
928 | bool LocalUse = false; | ||||||||
929 | if (!AllUsesDominatedByBlock(Reg, SuccToSinkTo, MBB, | ||||||||
930 | BreakPHIEdge, LocalUse)) | ||||||||
931 | return nullptr; | ||||||||
932 | |||||||||
933 | continue; | ||||||||
934 | } | ||||||||
935 | |||||||||
936 | // Otherwise, we should look at all the successors and decide which one | ||||||||
937 | // we should sink to. If we have reliable block frequency information | ||||||||
938 | // (frequency != 0) available, give successors with smaller frequencies | ||||||||
939 | // higher priority, otherwise prioritize smaller loop depths. | ||||||||
940 | for (MachineBasicBlock *SuccBlock : | ||||||||
941 | GetAllSortedSuccessors(MI, MBB, AllSuccessors)) { | ||||||||
942 | bool LocalUse = false; | ||||||||
943 | if (AllUsesDominatedByBlock(Reg, SuccBlock, MBB, | ||||||||
944 | BreakPHIEdge, LocalUse)) { | ||||||||
945 | SuccToSinkTo = SuccBlock; | ||||||||
946 | break; | ||||||||
947 | } | ||||||||
948 | if (LocalUse) | ||||||||
949 | // Def is used locally, it's never safe to move this def. | ||||||||
950 | return nullptr; | ||||||||
951 | } | ||||||||
952 | |||||||||
953 | // If we couldn't find a block to sink to, ignore this instruction. | ||||||||
954 | if (!SuccToSinkTo) | ||||||||
955 | return nullptr; | ||||||||
956 | if (!isProfitableToSinkTo(Reg, MI, MBB, SuccToSinkTo, AllSuccessors)) | ||||||||
957 | return nullptr; | ||||||||
958 | } | ||||||||
959 | } | ||||||||
960 | |||||||||
961 | // It is not possible to sink an instruction into its own block. This can | ||||||||
962 | // happen with loops. | ||||||||
963 | if (MBB == SuccToSinkTo) | ||||||||
964 | return nullptr; | ||||||||
965 | |||||||||
966 | // It's not safe to sink instructions to EH landing pad. Control flow into | ||||||||
967 | // landing pad is implicitly defined. | ||||||||
968 | if (SuccToSinkTo && SuccToSinkTo->isEHPad()) | ||||||||
969 | return nullptr; | ||||||||
970 | |||||||||
971 | // It ought to be okay to sink instructions into an INLINEASM_BR target, but | ||||||||
972 | // only if we make sure that MI occurs _before_ an INLINEASM_BR instruction in | ||||||||
973 | // the source block (which this code does not yet do). So for now, forbid | ||||||||
974 | // doing so. | ||||||||
975 | if (SuccToSinkTo && SuccToSinkTo->isInlineAsmBrIndirectTarget()) | ||||||||
976 | return nullptr; | ||||||||
977 | |||||||||
978 | return SuccToSinkTo; | ||||||||
979 | } | ||||||||
980 | |||||||||
981 | /// Return true if MI is likely to be usable as a memory operation by the | ||||||||
982 | /// implicit null check optimization. | ||||||||
983 | /// | ||||||||
984 | /// This is a "best effort" heuristic, and should not be relied upon for | ||||||||
985 | /// correctness. This returning true does not guarantee that the implicit null | ||||||||
986 | /// check optimization is legal over MI, and this returning false does not | ||||||||
987 | /// guarantee MI cannot possibly be used to do a null check. | ||||||||
988 | static bool SinkingPreventsImplicitNullCheck(MachineInstr &MI, | ||||||||
989 | const TargetInstrInfo *TII, | ||||||||
990 | const TargetRegisterInfo *TRI) { | ||||||||
991 | using MachineBranchPredicate = TargetInstrInfo::MachineBranchPredicate; | ||||||||
992 | |||||||||
993 | auto *MBB = MI.getParent(); | ||||||||
994 | if (MBB->pred_size() != 1) | ||||||||
995 | return false; | ||||||||
996 | |||||||||
997 | auto *PredMBB = *MBB->pred_begin(); | ||||||||
998 | auto *PredBB = PredMBB->getBasicBlock(); | ||||||||
999 | |||||||||
1000 | // Frontends that don't use implicit null checks have no reason to emit | ||||||||
1001 | // branches with make.implicit metadata, and this function should always | ||||||||
1002 | // return false for them. | ||||||||
1003 | if (!PredBB || | ||||||||
1004 | !PredBB->getTerminator()->getMetadata(LLVMContext::MD_make_implicit)) | ||||||||
1005 | return false; | ||||||||
1006 | |||||||||
1007 | const MachineOperand *BaseOp; | ||||||||
1008 | int64_t Offset; | ||||||||
1009 | bool OffsetIsScalable; | ||||||||
1010 | if (!TII->getMemOperandWithOffset(MI, BaseOp, Offset, OffsetIsScalable, TRI)) | ||||||||
1011 | return false; | ||||||||
1012 | |||||||||
1013 | if (!BaseOp->isReg()) | ||||||||
1014 | return false; | ||||||||
1015 | |||||||||
1016 | if (!(MI.mayLoad() && !MI.isPredicable())) | ||||||||
1017 | return false; | ||||||||
1018 | |||||||||
1019 | MachineBranchPredicate MBP; | ||||||||
1020 | if (TII->analyzeBranchPredicate(*PredMBB, MBP, false)) | ||||||||
1021 | return false; | ||||||||
1022 | |||||||||
1023 | return MBP.LHS.isReg() && MBP.RHS.isImm() && MBP.RHS.getImm() == 0 && | ||||||||
1024 | (MBP.Predicate == MachineBranchPredicate::PRED_NE || | ||||||||
1025 | MBP.Predicate == MachineBranchPredicate::PRED_EQ) && | ||||||||
1026 | MBP.LHS.getReg() == BaseOp->getReg(); | ||||||||
1027 | } | ||||||||
1028 | |||||||||
1029 | /// If the sunk instruction is a copy, try to forward the copy instead of | ||||||||
1030 | /// leaving an 'undef' DBG_VALUE in the original location. Don't do this if | ||||||||
1031 | /// there's any subregister weirdness involved. Returns true if copy | ||||||||
1032 | /// propagation occurred. | ||||||||
1033 | static bool attemptDebugCopyProp(MachineInstr &SinkInst, MachineInstr &DbgMI, | ||||||||
1034 | Register Reg) { | ||||||||
1035 | const MachineRegisterInfo &MRI = SinkInst.getMF()->getRegInfo(); | ||||||||
1036 | const TargetInstrInfo &TII = *SinkInst.getMF()->getSubtarget().getInstrInfo(); | ||||||||
1037 | |||||||||
1038 | // Copy DBG_VALUE operand and set the original to undef. We then check to | ||||||||
1039 | // see whether this is something that can be copy-forwarded. If it isn't, | ||||||||
1040 | // continue around the loop. | ||||||||
1041 | |||||||||
1042 | const MachineOperand *SrcMO = nullptr, *DstMO = nullptr; | ||||||||
1043 | auto CopyOperands = TII.isCopyInstr(SinkInst); | ||||||||
1044 | if (!CopyOperands) | ||||||||
1045 | return false; | ||||||||
1046 | SrcMO = CopyOperands->Source; | ||||||||
1047 | DstMO = CopyOperands->Destination; | ||||||||
1048 | |||||||||
1049 | // Check validity of forwarding this copy. | ||||||||
1050 | bool PostRA = MRI.getNumVirtRegs() == 0; | ||||||||
1051 | |||||||||
1052 | // Trying to forward between physical and virtual registers is too hard. | ||||||||
1053 | if (Reg.isVirtual() != SrcMO->getReg().isVirtual()) | ||||||||
1054 | return false; | ||||||||
1055 | |||||||||
1056 | // Only try virtual register copy-forwarding before regalloc, and physical | ||||||||
1057 | // register copy-forwarding after regalloc. | ||||||||
1058 | bool arePhysRegs = !Reg.isVirtual(); | ||||||||
1059 | if (arePhysRegs != PostRA) | ||||||||
1060 | return false; | ||||||||
1061 | |||||||||
1062 | // Pre-regalloc, only forward if all subregisters agree (or there are no | ||||||||
1063 | // subregs at all). More analysis might recover some forwardable copies. | ||||||||
1064 | if (!PostRA) | ||||||||
1065 | for (auto &DbgMO : DbgMI.getDebugOperandsForReg(Reg)) | ||||||||
1066 | if (DbgMO.getSubReg() != SrcMO->getSubReg() || | ||||||||
1067 | DbgMO.getSubReg() != DstMO->getSubReg()) | ||||||||
1068 | return false; | ||||||||
1069 | |||||||||
1070 | // Post-regalloc, we may be sinking a DBG_VALUE of a sub or super-register | ||||||||
1071 | // of this copy. Only forward the copy if the DBG_VALUE operand exactly | ||||||||
1072 | // matches the copy destination. | ||||||||
1073 | if (PostRA && Reg != DstMO->getReg()) | ||||||||
1074 | return false; | ||||||||
1075 | |||||||||
1076 | for (auto &DbgMO : DbgMI.getDebugOperandsForReg(Reg)) { | ||||||||
1077 | DbgMO.setReg(SrcMO->getReg()); | ||||||||
1078 | DbgMO.setSubReg(SrcMO->getSubReg()); | ||||||||
1079 | } | ||||||||
1080 | return true; | ||||||||
1081 | } | ||||||||
1082 | |||||||||
1083 | using MIRegs = std::pair<MachineInstr *, SmallVector<unsigned, 2>>; | ||||||||
1084 | /// Sink an instruction and its associated debug instructions. | ||||||||
1085 | static void performSink(MachineInstr &MI, MachineBasicBlock &SuccToSinkTo, | ||||||||
1086 | MachineBasicBlock::iterator InsertPos, | ||||||||
1087 | SmallVectorImpl<MIRegs> &DbgValuesToSink) { | ||||||||
1088 | |||||||||
1089 | // If we cannot find a location to use (merge with), then we erase the debug | ||||||||
1090 | // location to prevent debug-info driven tools from potentially reporting | ||||||||
1091 | // wrong location information. | ||||||||
1092 | if (!SuccToSinkTo.empty() && InsertPos != SuccToSinkTo.end()) | ||||||||
1093 | MI.setDebugLoc(DILocation::getMergedLocation(MI.getDebugLoc(), | ||||||||
1094 | InsertPos->getDebugLoc())); | ||||||||
1095 | else | ||||||||
1096 | MI.setDebugLoc(DebugLoc()); | ||||||||
1097 | |||||||||
1098 | // Move the instruction. | ||||||||
1099 | MachineBasicBlock *ParentBlock = MI.getParent(); | ||||||||
1100 | SuccToSinkTo.splice(InsertPos, ParentBlock, MI, | ||||||||
1101 | ++MachineBasicBlock::iterator(MI)); | ||||||||
1102 | |||||||||
1103 | // Sink a copy of debug users to the insert position. Mark the original | ||||||||
1104 | // DBG_VALUE location as 'undef', indicating that any earlier variable | ||||||||
1105 | // location should be terminated as we've optimised away the value at this | ||||||||
1106 | // point. | ||||||||
1107 | for (auto DbgValueToSink : DbgValuesToSink) { | ||||||||
1108 | MachineInstr *DbgMI = DbgValueToSink.first; | ||||||||
1109 | MachineInstr *NewDbgMI = DbgMI->getMF()->CloneMachineInstr(DbgMI); | ||||||||
1110 | SuccToSinkTo.insert(InsertPos, NewDbgMI); | ||||||||
1111 | |||||||||
1112 | bool PropagatedAllSunkOps = true; | ||||||||
1113 | for (unsigned Reg : DbgValueToSink.second) { | ||||||||
1114 | if (DbgMI->hasDebugOperandForReg(Reg)) { | ||||||||
1115 | if (!attemptDebugCopyProp(MI, *DbgMI, Reg)) { | ||||||||
1116 | PropagatedAllSunkOps = false; | ||||||||
1117 | break; | ||||||||
1118 | } | ||||||||
1119 | } | ||||||||
1120 | } | ||||||||
1121 | if (!PropagatedAllSunkOps) | ||||||||
1122 | DbgMI->setDebugValueUndef(); | ||||||||
1123 | } | ||||||||
1124 | } | ||||||||
1125 | |||||||||
1126 | /// hasStoreBetween - check if there is store betweeen straight line blocks From | ||||||||
1127 | /// and To. | ||||||||
1128 | bool MachineSinking::hasStoreBetween(MachineBasicBlock *From, | ||||||||
1129 | MachineBasicBlock *To, MachineInstr &MI) { | ||||||||
1130 | // Make sure From and To are in straight line which means From dominates To | ||||||||
1131 | // and To post dominates From. | ||||||||
1132 | if (!DT->dominates(From, To) || !PDT->dominates(To, From)) | ||||||||
1133 | return true; | ||||||||
1134 | |||||||||
1135 | auto BlockPair = std::make_pair(From, To); | ||||||||
1136 | |||||||||
1137 | // Does these two blocks pair be queried before and have a definite cached | ||||||||
1138 | // result? | ||||||||
1139 | if (HasStoreCache.find(BlockPair) != HasStoreCache.end()) | ||||||||
1140 | return HasStoreCache[BlockPair]; | ||||||||
1141 | |||||||||
1142 | if (StoreInstrCache.find(BlockPair) != StoreInstrCache.end()) | ||||||||
1143 | return llvm::any_of(StoreInstrCache[BlockPair], [&](MachineInstr *I) { | ||||||||
1144 | return I->mayAlias(AA, MI, false); | ||||||||
1145 | }); | ||||||||
1146 | |||||||||
1147 | bool SawStore = false; | ||||||||
1148 | bool HasAliasedStore = false; | ||||||||
1149 | DenseSet<MachineBasicBlock *> HandledBlocks; | ||||||||
1150 | DenseSet<MachineBasicBlock *> HandledDomBlocks; | ||||||||
1151 | // Go through all reachable blocks from From. | ||||||||
1152 | for (MachineBasicBlock *BB : depth_first(From)) { | ||||||||
1153 | // We insert the instruction at the start of block To, so no need to worry | ||||||||
1154 | // about stores inside To. | ||||||||
1155 | // Store in block From should be already considered when just enter function | ||||||||
1156 | // SinkInstruction. | ||||||||
1157 | if (BB == To || BB == From) | ||||||||
1158 | continue; | ||||||||
1159 | |||||||||
1160 | // We already handle this BB in previous iteration. | ||||||||
1161 | if (HandledBlocks.count(BB)) | ||||||||
1162 | continue; | ||||||||
1163 | |||||||||
1164 | HandledBlocks.insert(BB); | ||||||||
1165 | // To post dominates BB, it must be a path from block From. | ||||||||
1166 | if (PDT->dominates(To, BB)) { | ||||||||
1167 | if (!HandledDomBlocks.count(BB)) | ||||||||
1168 | HandledDomBlocks.insert(BB); | ||||||||
1169 | |||||||||
1170 | // If this BB is too big or the block number in straight line between From | ||||||||
1171 | // and To is too big, stop searching to save compiling time. | ||||||||
1172 | if (BB->size() > SinkLoadInstsPerBlockThreshold || | ||||||||
1173 | HandledDomBlocks.size() > SinkLoadBlocksThreshold) { | ||||||||
1174 | for (auto *DomBB : HandledDomBlocks) { | ||||||||
1175 | if (DomBB != BB && DT->dominates(DomBB, BB)) | ||||||||
1176 | HasStoreCache[std::make_pair(DomBB, To)] = true; | ||||||||
1177 | else if(DomBB != BB && DT->dominates(BB, DomBB)) | ||||||||
1178 | HasStoreCache[std::make_pair(From, DomBB)] = true; | ||||||||
1179 | } | ||||||||
1180 | HasStoreCache[BlockPair] = true; | ||||||||
1181 | return true; | ||||||||
1182 | } | ||||||||
1183 | |||||||||
1184 | for (MachineInstr &I : *BB) { | ||||||||
1185 | // Treat as alias conservatively for a call or an ordered memory | ||||||||
1186 | // operation. | ||||||||
1187 | if (I.isCall() || I.hasOrderedMemoryRef()) { | ||||||||
1188 | for (auto *DomBB : HandledDomBlocks) { | ||||||||
1189 | if (DomBB != BB && DT->dominates(DomBB, BB)) | ||||||||
1190 | HasStoreCache[std::make_pair(DomBB, To)] = true; | ||||||||
1191 | else if(DomBB != BB && DT->dominates(BB, DomBB)) | ||||||||
1192 | HasStoreCache[std::make_pair(From, DomBB)] = true; | ||||||||
1193 | } | ||||||||
1194 | HasStoreCache[BlockPair] = true; | ||||||||
1195 | return true; | ||||||||
1196 | } | ||||||||
1197 | |||||||||
1198 | if (I.mayStore()) { | ||||||||
1199 | SawStore = true; | ||||||||
1200 | // We still have chance to sink MI if all stores between are not | ||||||||
1201 | // aliased to MI. | ||||||||
1202 | // Cache all store instructions, so that we don't need to go through | ||||||||
1203 | // all From reachable blocks for next load instruction. | ||||||||
1204 | if (I.mayAlias(AA, MI, false)) | ||||||||
1205 | HasAliasedStore = true; | ||||||||
1206 | StoreInstrCache[BlockPair].push_back(&I); | ||||||||
1207 | } | ||||||||
1208 | } | ||||||||
1209 | } | ||||||||
1210 | } | ||||||||
1211 | // If there is no store at all, cache the result. | ||||||||
1212 | if (!SawStore) | ||||||||
1213 | HasStoreCache[BlockPair] = false; | ||||||||
1214 | return HasAliasedStore; | ||||||||
1215 | } | ||||||||
1216 | |||||||||
1217 | /// Sink instructions into loops if profitable. This especially tries to prevent | ||||||||
1218 | /// register spills caused by register pressure if there is little to no | ||||||||
1219 | /// overhead moving instructions into loops. | ||||||||
1220 | bool MachineSinking::SinkIntoLoop(MachineLoop *L, MachineInstr &I) { | ||||||||
1221 | LLVM_DEBUG(dbgs() << "LoopSink: Finding sink block for: " << I)do { } while (false); | ||||||||
1222 | MachineBasicBlock *Preheader = L->getLoopPreheader(); | ||||||||
1223 | assert(Preheader && "Loop sink needs a preheader block")((void)0); | ||||||||
1224 | MachineBasicBlock *SinkBlock = nullptr; | ||||||||
1225 | bool CanSink = true; | ||||||||
1226 | const MachineOperand &MO = I.getOperand(0); | ||||||||
1227 | |||||||||
1228 | for (MachineInstr &MI : MRI->use_instructions(MO.getReg())) { | ||||||||
1229 | LLVM_DEBUG(dbgs() << "LoopSink: Analysing use: " << MI)do { } while (false); | ||||||||
1230 | if (!L->contains(&MI)) { | ||||||||
1231 | LLVM_DEBUG(dbgs() << "LoopSink: Use not in loop, can't sink.\n")do { } while (false); | ||||||||
1232 | CanSink = false; | ||||||||
1233 | break; | ||||||||
1234 | } | ||||||||
1235 | |||||||||
1236 | // FIXME: Come up with a proper cost model that estimates whether sinking | ||||||||
1237 | // the instruction (and thus possibly executing it on every loop | ||||||||
1238 | // iteration) is more expensive than a register. | ||||||||
1239 | // For now assumes that copies are cheap and thus almost always worth it. | ||||||||
1240 | if (!MI.isCopy()) { | ||||||||
1241 | LLVM_DEBUG(dbgs() << "LoopSink: Use is not a copy\n")do { } while (false); | ||||||||
1242 | CanSink = false; | ||||||||
1243 | break; | ||||||||
1244 | } | ||||||||
1245 | if (!SinkBlock
| ||||||||
1246 | SinkBlock = MI.getParent(); | ||||||||
1247 | LLVM_DEBUG(dbgs() << "LoopSink: Setting sink block to: "do { } while (false) | ||||||||
1248 | << printMBBReference(*SinkBlock) << "\n")do { } while (false); | ||||||||
1249 | continue; | ||||||||
1250 | } | ||||||||
1251 | SinkBlock = DT->findNearestCommonDominator(SinkBlock, MI.getParent()); | ||||||||
1252 | if (!SinkBlock) { | ||||||||
1253 | LLVM_DEBUG(dbgs() << "LoopSink: Can't find nearest dominator\n")do { } while (false); | ||||||||
1254 | CanSink = false; | ||||||||
1255 | break; | ||||||||
1256 | } | ||||||||
1257 | LLVM_DEBUG(dbgs() << "LoopSink: Setting nearest common dom block: " <<do { } while (false) | ||||||||
1258 | printMBBReference(*SinkBlock) << "\n")do { } while (false); | ||||||||
1259 | } | ||||||||
1260 | |||||||||
1261 | if (!CanSink) { | ||||||||
1262 | LLVM_DEBUG(dbgs() << "LoopSink: Can't sink instruction.\n")do { } while (false); | ||||||||
1263 | return false; | ||||||||
1264 | } | ||||||||
1265 | if (!SinkBlock) { | ||||||||
1266 | LLVM_DEBUG(dbgs() << "LoopSink: Not sinking, can't find sink block.\n")do { } while (false); | ||||||||
1267 | return false; | ||||||||
1268 | } | ||||||||
1269 | if (SinkBlock == Preheader) { | ||||||||
1270 | LLVM_DEBUG(dbgs() << "LoopSink: Not sinking, sink block is the preheader\n")do { } while (false); | ||||||||
1271 | return false; | ||||||||
1272 | } | ||||||||
1273 | if (SinkBlock->size() > SinkLoadInstsPerBlockThreshold) { | ||||||||
1274 | LLVM_DEBUG(dbgs() << "LoopSink: Not Sinking, block too large to analyse.\n")do { } while (false); | ||||||||
1275 | return false; | ||||||||
1276 | } | ||||||||
1277 | |||||||||
1278 | LLVM_DEBUG(dbgs() << "LoopSink: Sinking instruction!\n")do { } while (false); | ||||||||
1279 | SinkBlock->splice(SinkBlock->getFirstNonPHI(), Preheader, I); | ||||||||
1280 | |||||||||
1281 | // The instruction is moved from its basic block, so do not retain the | ||||||||
1282 | // debug information. | ||||||||
1283 | assert(!I.isDebugInstr() && "Should not sink debug inst")((void)0); | ||||||||
1284 | I.setDebugLoc(DebugLoc()); | ||||||||
1285 | return true; | ||||||||
1286 | } | ||||||||
1287 | |||||||||
1288 | /// SinkInstruction - Determine whether it is safe to sink the specified machine | ||||||||
1289 | /// instruction out of its current block into a successor. | ||||||||
1290 | bool MachineSinking::SinkInstruction(MachineInstr &MI, bool &SawStore, | ||||||||
1291 | AllSuccsCache &AllSuccessors) { | ||||||||
1292 | // Don't sink instructions that the target prefers not to sink. | ||||||||
1293 | if (!TII->shouldSink(MI)) | ||||||||
1294 | return false; | ||||||||
1295 | |||||||||
1296 | // Check if it's safe to move the instruction. | ||||||||
1297 | if (!MI.isSafeToMove(AA, SawStore)) | ||||||||
1298 | return false; | ||||||||
1299 | |||||||||
1300 | // Convergent operations may not be made control-dependent on additional | ||||||||
1301 | // values. | ||||||||
1302 | if (MI.isConvergent()) | ||||||||
1303 | return false; | ||||||||
1304 | |||||||||
1305 | // Don't break implicit null checks. This is a performance heuristic, and not | ||||||||
1306 | // required for correctness. | ||||||||
1307 | if (SinkingPreventsImplicitNullCheck(MI, TII, TRI)) | ||||||||
1308 | return false; | ||||||||
1309 | |||||||||
1310 | // FIXME: This should include support for sinking instructions within the | ||||||||
1311 | // block they are currently in to shorten the live ranges. We often get | ||||||||
1312 | // instructions sunk into the top of a large block, but it would be better to | ||||||||
1313 | // also sink them down before their first use in the block. This xform has to | ||||||||
1314 | // be careful not to *increase* register pressure though, e.g. sinking | ||||||||
1315 | // "x = y + z" down if it kills y and z would increase the live ranges of y | ||||||||
1316 | // and z and only shrink the live range of x. | ||||||||
1317 | |||||||||
1318 | bool BreakPHIEdge = false; | ||||||||
1319 | MachineBasicBlock *ParentBlock = MI.getParent(); | ||||||||
1320 | MachineBasicBlock *SuccToSinkTo = | ||||||||
1321 | FindSuccToSinkTo(MI, ParentBlock, BreakPHIEdge, AllSuccessors); | ||||||||
1322 | |||||||||
1323 | // If there are no outputs, it must have side-effects. | ||||||||
1324 | if (!SuccToSinkTo) | ||||||||
1325 | return false; | ||||||||
1326 | |||||||||
1327 | // If the instruction to move defines a dead physical register which is live | ||||||||
1328 | // when leaving the basic block, don't move it because it could turn into a | ||||||||
1329 | // "zombie" define of that preg. E.g., EFLAGS. (<rdar://problem/8030636>) | ||||||||
1330 | for (unsigned I = 0, E = MI.getNumOperands(); I != E; ++I) { | ||||||||
1331 | const MachineOperand &MO = MI.getOperand(I); | ||||||||
1332 | if (!MO.isReg()) continue; | ||||||||
1333 | Register Reg = MO.getReg(); | ||||||||
1334 | if (Reg == 0 || !Register::isPhysicalRegister(Reg)) | ||||||||
1335 | continue; | ||||||||
1336 | if (SuccToSinkTo->isLiveIn(Reg)) | ||||||||
1337 | return false; | ||||||||
1338 | } | ||||||||
1339 | |||||||||
1340 | LLVM_DEBUG(dbgs() << "Sink instr " << MI << "\tinto block " << *SuccToSinkTo)do { } while (false); | ||||||||
1341 | |||||||||
1342 | // If the block has multiple predecessors, this is a critical edge. | ||||||||
1343 | // Decide if we can sink along it or need to break the edge. | ||||||||
1344 | if (SuccToSinkTo->pred_size() > 1) { | ||||||||
1345 | // We cannot sink a load across a critical edge - there may be stores in | ||||||||
1346 | // other code paths. | ||||||||
1347 | bool TryBreak = false; | ||||||||
1348 | bool Store = | ||||||||
1349 | MI.mayLoad() ? hasStoreBetween(ParentBlock, SuccToSinkTo, MI) : true; | ||||||||
1350 | if (!MI.isSafeToMove(AA, Store)) { | ||||||||
1351 | LLVM_DEBUG(dbgs() << " *** NOTE: Won't sink load along critical edge.\n")do { } while (false); | ||||||||
1352 | TryBreak = true; | ||||||||
1353 | } | ||||||||
1354 | |||||||||
1355 | // We don't want to sink across a critical edge if we don't dominate the | ||||||||
1356 | // successor. We could be introducing calculations to new code paths. | ||||||||
1357 | if (!TryBreak && !DT->dominates(ParentBlock, SuccToSinkTo)) { | ||||||||
1358 | LLVM_DEBUG(dbgs() << " *** NOTE: Critical edge found\n")do { } while (false); | ||||||||
1359 | TryBreak = true; | ||||||||
1360 | } | ||||||||
1361 | |||||||||
1362 | // Don't sink instructions into a loop. | ||||||||
1363 | if (!TryBreak && LI->isLoopHeader(SuccToSinkTo)) { | ||||||||
1364 | LLVM_DEBUG(dbgs() << " *** NOTE: Loop header found\n")do { } while (false); | ||||||||
1365 | TryBreak = true; | ||||||||
1366 | } | ||||||||
1367 | |||||||||
1368 | // Otherwise we are OK with sinking along a critical edge. | ||||||||
1369 | if (!TryBreak) | ||||||||
1370 | LLVM_DEBUG(dbgs() << "Sinking along critical edge.\n")do { } while (false); | ||||||||
1371 | else { | ||||||||
1372 | // Mark this edge as to be split. | ||||||||
1373 | // If the edge can actually be split, the next iteration of the main loop | ||||||||
1374 | // will sink MI in the newly created block. | ||||||||
1375 | bool Status = | ||||||||
1376 | PostponeSplitCriticalEdge(MI, ParentBlock, SuccToSinkTo, BreakPHIEdge); | ||||||||
1377 | if (!Status) | ||||||||
1378 | LLVM_DEBUG(dbgs() << " *** PUNTING: Not legal or profitable to "do { } while (false) | ||||||||
1379 | "break critical edge\n")do { } while (false); | ||||||||
1380 | // The instruction will not be sunk this time. | ||||||||
1381 | return false; | ||||||||
1382 | } | ||||||||
1383 | } | ||||||||
1384 | |||||||||
1385 | if (BreakPHIEdge) { | ||||||||
1386 | // BreakPHIEdge is true if all the uses are in the successor MBB being | ||||||||
1387 | // sunken into and they are all PHI nodes. In this case, machine-sink must | ||||||||
1388 | // break the critical edge first. | ||||||||
1389 | bool Status = PostponeSplitCriticalEdge(MI, ParentBlock, | ||||||||
1390 | SuccToSinkTo, BreakPHIEdge); | ||||||||
1391 | if (!Status) | ||||||||
1392 | LLVM_DEBUG(dbgs() << " *** PUNTING: Not legal or profitable to "do { } while (false) | ||||||||
1393 | "break critical edge\n")do { } while (false); | ||||||||
1394 | // The instruction will not be sunk this time. | ||||||||
1395 | return false; | ||||||||
1396 | } | ||||||||
1397 | |||||||||
1398 | // Determine where to insert into. Skip phi nodes. | ||||||||
1399 | MachineBasicBlock::iterator InsertPos = SuccToSinkTo->begin(); | ||||||||
1400 | while (InsertPos != SuccToSinkTo->end() && InsertPos->isPHI()) | ||||||||
1401 | ++InsertPos; | ||||||||
1402 | |||||||||
1403 | // Collect debug users of any vreg that this inst defines. | ||||||||
1404 | SmallVector<MIRegs, 4> DbgUsersToSink; | ||||||||
1405 | for (auto &MO : MI.operands()) { | ||||||||
1406 | if (!MO.isReg() || !MO.isDef() || !MO.getReg().isVirtual()) | ||||||||
1407 | continue; | ||||||||
1408 | if (!SeenDbgUsers.count(MO.getReg())) | ||||||||
1409 | continue; | ||||||||
1410 | |||||||||
1411 | // Sink any users that don't pass any other DBG_VALUEs for this variable. | ||||||||
1412 | auto &Users = SeenDbgUsers[MO.getReg()]; | ||||||||
1413 | for (auto &User : Users) { | ||||||||
1414 | MachineInstr *DbgMI = User.getPointer(); | ||||||||
1415 | if (User.getInt()) { | ||||||||
1416 | // This DBG_VALUE would re-order assignments. If we can't copy-propagate | ||||||||
1417 | // it, it can't be recovered. Set it undef. | ||||||||
1418 | if (!attemptDebugCopyProp(MI, *DbgMI, MO.getReg())) | ||||||||
1419 | DbgMI->setDebugValueUndef(); | ||||||||
1420 | } else { | ||||||||
1421 | DbgUsersToSink.push_back( | ||||||||
1422 | {DbgMI, SmallVector<unsigned, 2>(1, MO.getReg())}); | ||||||||
1423 | } | ||||||||
1424 | } | ||||||||
1425 | } | ||||||||
1426 | |||||||||
1427 | // After sinking, some debug users may not be dominated any more. If possible, | ||||||||
1428 | // copy-propagate their operands. As it's expensive, don't do this if there's | ||||||||
1429 | // no debuginfo in the program. | ||||||||
1430 | if (MI.getMF()->getFunction().getSubprogram() && MI.isCopy()) | ||||||||
1431 | SalvageUnsunkDebugUsersOfCopy(MI, SuccToSinkTo); | ||||||||
1432 | |||||||||
1433 | performSink(MI, *SuccToSinkTo, InsertPos, DbgUsersToSink); | ||||||||
1434 | |||||||||
1435 | // Conservatively, clear any kill flags, since it's possible that they are no | ||||||||
1436 | // longer correct. | ||||||||
1437 | // Note that we have to clear the kill flags for any register this instruction | ||||||||
1438 | // uses as we may sink over another instruction which currently kills the | ||||||||
1439 | // used registers. | ||||||||
1440 | for (MachineOperand &MO : MI.operands()) { | ||||||||
1441 | if (MO.isReg() && MO.isUse()) | ||||||||
1442 | RegsToClearKillFlags.set(MO.getReg()); // Remember to clear kill flags. | ||||||||
1443 | } | ||||||||
1444 | |||||||||
1445 | return true; | ||||||||
1446 | } | ||||||||
1447 | |||||||||
1448 | void MachineSinking::SalvageUnsunkDebugUsersOfCopy( | ||||||||
1449 | MachineInstr &MI, MachineBasicBlock *TargetBlock) { | ||||||||
1450 | assert(MI.isCopy())((void)0); | ||||||||
1451 | assert(MI.getOperand(1).isReg())((void)0); | ||||||||
1452 | |||||||||
1453 | // Enumerate all users of vreg operands that are def'd. Skip those that will | ||||||||
1454 | // be sunk. For the rest, if they are not dominated by the block we will sink | ||||||||
1455 | // MI into, propagate the copy source to them. | ||||||||
1456 | SmallVector<MachineInstr *, 4> DbgDefUsers; | ||||||||
1457 | SmallVector<Register, 4> DbgUseRegs; | ||||||||
1458 | const MachineRegisterInfo &MRI = MI.getMF()->getRegInfo(); | ||||||||
1459 | for (auto &MO : MI.operands()) { | ||||||||
1460 | if (!MO.isReg() || !MO.isDef() || !MO.getReg().isVirtual()) | ||||||||
1461 | continue; | ||||||||
1462 | DbgUseRegs.push_back(MO.getReg()); | ||||||||
1463 | for (auto &User : MRI.use_instructions(MO.getReg())) { | ||||||||
1464 | if (!User.isDebugValue() || DT->dominates(TargetBlock, User.getParent())) | ||||||||
1465 | continue; | ||||||||
1466 | |||||||||
1467 | // If is in same block, will either sink or be use-before-def. | ||||||||
1468 | if (User.getParent() == MI.getParent()) | ||||||||
1469 | continue; | ||||||||
1470 | |||||||||
1471 | assert(User.hasDebugOperandForReg(MO.getReg()) &&((void)0) | ||||||||
1472 | "DBG_VALUE user of vreg, but has no operand for it?")((void)0); | ||||||||
1473 | DbgDefUsers.push_back(&User); | ||||||||
1474 | } | ||||||||
1475 | } | ||||||||
1476 | |||||||||
1477 | // Point the users of this copy that are no longer dominated, at the source | ||||||||
1478 | // of the copy. | ||||||||
1479 | for (auto *User : DbgDefUsers) { | ||||||||
1480 | for (auto &Reg : DbgUseRegs) { | ||||||||
1481 | for (auto &DbgOp : User->getDebugOperandsForReg(Reg)) { | ||||||||
1482 | DbgOp.setReg(MI.getOperand(1).getReg()); | ||||||||
1483 | DbgOp.setSubReg(MI.getOperand(1).getSubReg()); | ||||||||
1484 | } | ||||||||
1485 | } | ||||||||
1486 | } | ||||||||
1487 | } | ||||||||
1488 | |||||||||
1489 | //===----------------------------------------------------------------------===// | ||||||||
1490 | // This pass is not intended to be a replacement or a complete alternative | ||||||||
1491 | // for the pre-ra machine sink pass. It is only designed to sink COPY | ||||||||
1492 | // instructions which should be handled after RA. | ||||||||
1493 | // | ||||||||
1494 | // This pass sinks COPY instructions into a successor block, if the COPY is not | ||||||||
1495 | // used in the current block and the COPY is live-in to a single successor | ||||||||
1496 | // (i.e., doesn't require the COPY to be duplicated). This avoids executing the | ||||||||
1497 | // copy on paths where their results aren't needed. This also exposes | ||||||||
1498 | // additional opportunites for dead copy elimination and shrink wrapping. | ||||||||
1499 | // | ||||||||
1500 | // These copies were either not handled by or are inserted after the MachineSink | ||||||||
1501 | // pass. As an example of the former case, the MachineSink pass cannot sink | ||||||||
1502 | // COPY instructions with allocatable source registers; for AArch64 these type | ||||||||
1503 | // of copy instructions are frequently used to move function parameters (PhyReg) | ||||||||
1504 | // into virtual registers in the entry block. | ||||||||
1505 | // | ||||||||
1506 | // For the machine IR below, this pass will sink %w19 in the entry into its | ||||||||
1507 | // successor (%bb.1) because %w19 is only live-in in %bb.1. | ||||||||
1508 | // %bb.0: | ||||||||
1509 | // %wzr = SUBSWri %w1, 1 | ||||||||
1510 | // %w19 = COPY %w0 | ||||||||
1511 | // Bcc 11, %bb.2 | ||||||||
1512 | // %bb.1: | ||||||||
1513 | // Live Ins: %w19 | ||||||||
1514 | // BL @fun | ||||||||
1515 | // %w0 = ADDWrr %w0, %w19 | ||||||||
1516 | // RET %w0 | ||||||||
1517 | // %bb.2: | ||||||||
1518 | // %w0 = COPY %wzr | ||||||||
1519 | // RET %w0 | ||||||||
1520 | // As we sink %w19 (CSR in AArch64) into %bb.1, the shrink-wrapping pass will be | ||||||||
1521 | // able to see %bb.0 as a candidate. | ||||||||
1522 | //===----------------------------------------------------------------------===// | ||||||||
1523 | namespace { | ||||||||
1524 | |||||||||
1525 | class PostRAMachineSinking : public MachineFunctionPass { | ||||||||
1526 | public: | ||||||||
1527 | bool runOnMachineFunction(MachineFunction &MF) override; | ||||||||
1528 | |||||||||
1529 | static char ID; | ||||||||
1530 | PostRAMachineSinking() : MachineFunctionPass(ID) {} | ||||||||
1531 | StringRef getPassName() const override { return "PostRA Machine Sink"; } | ||||||||
1532 | |||||||||
1533 | void getAnalysisUsage(AnalysisUsage &AU) const override { | ||||||||
1534 | AU.setPreservesCFG(); | ||||||||
1535 | MachineFunctionPass::getAnalysisUsage(AU); | ||||||||
1536 | } | ||||||||
1537 | |||||||||
1538 | MachineFunctionProperties getRequiredProperties() const override { | ||||||||
1539 | return MachineFunctionProperties().set( | ||||||||
1540 | MachineFunctionProperties::Property::NoVRegs); | ||||||||
1541 | } | ||||||||
1542 | |||||||||
1543 | private: | ||||||||
1544 | /// Track which register units have been modified and used. | ||||||||
1545 | LiveRegUnits ModifiedRegUnits, UsedRegUnits; | ||||||||
1546 | |||||||||
1547 | /// Track DBG_VALUEs of (unmodified) register units. Each DBG_VALUE has an | ||||||||
1548 | /// entry in this map for each unit it touches. The DBG_VALUE's entry | ||||||||
1549 | /// consists of a pointer to the instruction itself, and a vector of registers | ||||||||
1550 | /// referred to by the instruction that overlap the key register unit. | ||||||||
1551 | DenseMap<unsigned, SmallVector<MIRegs, 2>> SeenDbgInstrs; | ||||||||
1552 | |||||||||
1553 | /// Sink Copy instructions unused in the same block close to their uses in | ||||||||
1554 | /// successors. | ||||||||
1555 | bool tryToSinkCopy(MachineBasicBlock &BB, MachineFunction &MF, | ||||||||
1556 | const TargetRegisterInfo *TRI, const TargetInstrInfo *TII); | ||||||||
1557 | }; | ||||||||
1558 | } // namespace | ||||||||
1559 | |||||||||
1560 | char PostRAMachineSinking::ID = 0; | ||||||||
1561 | char &llvm::PostRAMachineSinkingID = PostRAMachineSinking::ID; | ||||||||
1562 | |||||||||
1563 | INITIALIZE_PASS(PostRAMachineSinking, "postra-machine-sink",static void *initializePostRAMachineSinkingPassOnce(PassRegistry &Registry) { PassInfo *PI = new PassInfo( "PostRA Machine Sink" , "postra-machine-sink", &PostRAMachineSinking::ID, PassInfo ::NormalCtor_t(callDefaultCtor<PostRAMachineSinking>), false , false); Registry.registerPass(*PI, true); return PI; } static llvm::once_flag InitializePostRAMachineSinkingPassFlag; void llvm::initializePostRAMachineSinkingPass(PassRegistry &Registry ) { llvm::call_once(InitializePostRAMachineSinkingPassFlag, initializePostRAMachineSinkingPassOnce , std::ref(Registry)); } | ||||||||
1564 | "PostRA Machine Sink", false, false)static void *initializePostRAMachineSinkingPassOnce(PassRegistry &Registry) { PassInfo *PI = new PassInfo( "PostRA Machine Sink" , "postra-machine-sink", &PostRAMachineSinking::ID, PassInfo ::NormalCtor_t(callDefaultCtor<PostRAMachineSinking>), false , false); Registry.registerPass(*PI, true); return PI; } static llvm::once_flag InitializePostRAMachineSinkingPassFlag; void llvm::initializePostRAMachineSinkingPass(PassRegistry &Registry ) { llvm::call_once(InitializePostRAMachineSinkingPassFlag, initializePostRAMachineSinkingPassOnce , std::ref(Registry)); } | ||||||||
1565 | |||||||||
1566 | static bool aliasWithRegsInLiveIn(MachineBasicBlock &MBB, unsigned Reg, | ||||||||
1567 | const TargetRegisterInfo *TRI) { | ||||||||
1568 | LiveRegUnits LiveInRegUnits(*TRI); | ||||||||
1569 | LiveInRegUnits.addLiveIns(MBB); | ||||||||
1570 | return !LiveInRegUnits.available(Reg); | ||||||||
1571 | } | ||||||||
1572 | |||||||||
1573 | static MachineBasicBlock * | ||||||||
1574 | getSingleLiveInSuccBB(MachineBasicBlock &CurBB, | ||||||||
1575 | const SmallPtrSetImpl<MachineBasicBlock *> &SinkableBBs, | ||||||||
1576 | unsigned Reg, const TargetRegisterInfo *TRI) { | ||||||||
1577 | // Try to find a single sinkable successor in which Reg is live-in. | ||||||||
1578 | MachineBasicBlock *BB = nullptr; | ||||||||
1579 | for (auto *SI : SinkableBBs) { | ||||||||
1580 | if (aliasWithRegsInLiveIn(*SI, Reg, TRI)) { | ||||||||
1581 | // If BB is set here, Reg is live-in to at least two sinkable successors, | ||||||||
1582 | // so quit. | ||||||||
1583 | if (BB) | ||||||||
1584 | return nullptr; | ||||||||
1585 | BB = SI; | ||||||||
1586 | } | ||||||||
1587 | } | ||||||||
1588 | // Reg is not live-in to any sinkable successors. | ||||||||
1589 | if (!BB) | ||||||||
1590 | return nullptr; | ||||||||
1591 | |||||||||
1592 | // Check if any register aliased with Reg is live-in in other successors. | ||||||||
1593 | for (auto *SI : CurBB.successors()) { | ||||||||
1594 | if (!SinkableBBs.count(SI) && aliasWithRegsInLiveIn(*SI, Reg, TRI)) | ||||||||
1595 | return nullptr; | ||||||||
1596 | } | ||||||||
1597 | return BB; | ||||||||
1598 | } | ||||||||
1599 | |||||||||
1600 | static MachineBasicBlock * | ||||||||
1601 | getSingleLiveInSuccBB(MachineBasicBlock &CurBB, | ||||||||
1602 | const SmallPtrSetImpl<MachineBasicBlock *> &SinkableBBs, | ||||||||
1603 | ArrayRef<unsigned> DefedRegsInCopy, | ||||||||
1604 | const TargetRegisterInfo *TRI) { | ||||||||
1605 | MachineBasicBlock *SingleBB = nullptr; | ||||||||
1606 | for (auto DefReg : DefedRegsInCopy) { | ||||||||
1607 | MachineBasicBlock *BB = | ||||||||
1608 | getSingleLiveInSuccBB(CurBB, SinkableBBs, DefReg, TRI); | ||||||||
1609 | if (!BB || (SingleBB && SingleBB != BB)) | ||||||||
1610 | return nullptr; | ||||||||
1611 | SingleBB = BB; | ||||||||
1612 | } | ||||||||
1613 | return SingleBB; | ||||||||
1614 | } | ||||||||
1615 | |||||||||
1616 | static void clearKillFlags(MachineInstr *MI, MachineBasicBlock &CurBB, | ||||||||
1617 | SmallVectorImpl<unsigned> &UsedOpsInCopy, | ||||||||
1618 | LiveRegUnits &UsedRegUnits, | ||||||||
1619 | const TargetRegisterInfo *TRI) { | ||||||||
1620 | for (auto U : UsedOpsInCopy) { | ||||||||
1621 | MachineOperand &MO = MI->getOperand(U); | ||||||||
1622 | Register SrcReg = MO.getReg(); | ||||||||
1623 | if (!UsedRegUnits.available(SrcReg)) { | ||||||||
1624 | MachineBasicBlock::iterator NI = std::next(MI->getIterator()); | ||||||||
1625 | for (MachineInstr &UI : make_range(NI, CurBB.end())) { | ||||||||
1626 | if (UI.killsRegister(SrcReg, TRI)) { | ||||||||
1627 | UI.clearRegisterKills(SrcReg, TRI); | ||||||||
1628 | MO.setIsKill(true); | ||||||||
1629 | break; | ||||||||
1630 | } | ||||||||
1631 | } | ||||||||
1632 | } | ||||||||
1633 | } | ||||||||
1634 | } | ||||||||
1635 | |||||||||
1636 | static void updateLiveIn(MachineInstr *MI, MachineBasicBlock *SuccBB, | ||||||||
1637 | SmallVectorImpl<unsigned> &UsedOpsInCopy, | ||||||||
1638 | SmallVectorImpl<unsigned> &DefedRegsInCopy) { | ||||||||
1639 | MachineFunction &MF = *SuccBB->getParent(); | ||||||||
1640 | const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo(); | ||||||||
1641 | for (unsigned DefReg : DefedRegsInCopy) | ||||||||
1642 | for (MCSubRegIterator S(DefReg, TRI, true); S.isValid(); ++S) | ||||||||
1643 | SuccBB->removeLiveIn(*S); | ||||||||
1644 | for (auto U : UsedOpsInCopy) { | ||||||||
1645 | Register SrcReg = MI->getOperand(U).getReg(); | ||||||||
1646 | LaneBitmask Mask; | ||||||||
1647 | for (MCRegUnitMaskIterator S(SrcReg, TRI); S.isValid(); ++S) { | ||||||||
1648 | Mask |= (*S).second; | ||||||||
1649 | } | ||||||||
1650 | SuccBB->addLiveIn(SrcReg, Mask.any() ? Mask : LaneBitmask::getAll()); | ||||||||
1651 | } | ||||||||
1652 | SuccBB->sortUniqueLiveIns(); | ||||||||
1653 | } | ||||||||
1654 | |||||||||
1655 | static bool hasRegisterDependency(MachineInstr *MI, | ||||||||
1656 | SmallVectorImpl<unsigned> &UsedOpsInCopy, | ||||||||
1657 | SmallVectorImpl<unsigned> &DefedRegsInCopy, | ||||||||
1658 | LiveRegUnits &ModifiedRegUnits, | ||||||||
1659 | LiveRegUnits &UsedRegUnits) { | ||||||||
1660 | bool HasRegDependency = false; | ||||||||
1661 | for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { | ||||||||
1662 | MachineOperand &MO = MI->getOperand(i); | ||||||||
1663 | if (!MO.isReg()) | ||||||||
1664 | continue; | ||||||||
1665 | Register Reg = MO.getReg(); | ||||||||
1666 | if (!Reg) | ||||||||
1667 | continue; | ||||||||
1668 | if (MO.isDef()) { | ||||||||
1669 | if (!ModifiedRegUnits.available(Reg) || !UsedRegUnits.available(Reg)) { | ||||||||
1670 | HasRegDependency = true; | ||||||||
1671 | break; | ||||||||
1672 | } | ||||||||
1673 | DefedRegsInCopy.push_back(Reg); | ||||||||
1674 | |||||||||
1675 | // FIXME: instead of isUse(), readsReg() would be a better fix here, | ||||||||
1676 | // For example, we can ignore modifications in reg with undef. However, | ||||||||
1677 | // it's not perfectly clear if skipping the internal read is safe in all | ||||||||
1678 | // other targets. | ||||||||
1679 | } else if (MO.isUse()) { | ||||||||
1680 | if (!ModifiedRegUnits.available(Reg)) { | ||||||||
1681 | HasRegDependency = true; | ||||||||
1682 | break; | ||||||||
1683 | } | ||||||||
1684 | UsedOpsInCopy.push_back(i); | ||||||||
1685 | } | ||||||||
1686 | } | ||||||||
1687 | return HasRegDependency; | ||||||||
1688 | } | ||||||||
1689 | |||||||||
1690 | static SmallSet<MCRegister, 4> getRegUnits(MCRegister Reg, | ||||||||
1691 | const TargetRegisterInfo *TRI) { | ||||||||
1692 | SmallSet<MCRegister, 4> RegUnits; | ||||||||
1693 | for (auto RI = MCRegUnitIterator(Reg, TRI); RI.isValid(); ++RI) | ||||||||
1694 | RegUnits.insert(*RI); | ||||||||
1695 | return RegUnits; | ||||||||
1696 | } | ||||||||
1697 | |||||||||
1698 | bool PostRAMachineSinking::tryToSinkCopy(MachineBasicBlock &CurBB, | ||||||||
1699 | MachineFunction &MF, | ||||||||
1700 | const TargetRegisterInfo *TRI, | ||||||||
1701 | const TargetInstrInfo *TII) { | ||||||||
1702 | SmallPtrSet<MachineBasicBlock *, 2> SinkableBBs; | ||||||||
1703 | // FIXME: For now, we sink only to a successor which has a single predecessor | ||||||||
1704 | // so that we can directly sink COPY instructions to the successor without | ||||||||
1705 | // adding any new block or branch instruction. | ||||||||
1706 | for (MachineBasicBlock *SI : CurBB.successors()) | ||||||||
1707 | if (!SI->livein_empty() && SI->pred_size() == 1) | ||||||||
1708 | SinkableBBs.insert(SI); | ||||||||
1709 | |||||||||
1710 | if (SinkableBBs.empty()) | ||||||||
1711 | return false; | ||||||||
1712 | |||||||||
1713 | bool Changed = false; | ||||||||
1714 | |||||||||
1715 | // Track which registers have been modified and used between the end of the | ||||||||
1716 | // block and the current instruction. | ||||||||
1717 | ModifiedRegUnits.clear(); | ||||||||
1718 | UsedRegUnits.clear(); | ||||||||
1719 | SeenDbgInstrs.clear(); | ||||||||
1720 | |||||||||
1721 | for (auto I = CurBB.rbegin(), E = CurBB.rend(); I != E;) { | ||||||||
1722 | MachineInstr *MI = &*I; | ||||||||
1723 | ++I; | ||||||||
1724 | |||||||||
1725 | // Track the operand index for use in Copy. | ||||||||
1726 | SmallVector<unsigned, 2> UsedOpsInCopy; | ||||||||
1727 | // Track the register number defed in Copy. | ||||||||
1728 | SmallVector<unsigned, 2> DefedRegsInCopy; | ||||||||
1729 | |||||||||
1730 | // We must sink this DBG_VALUE if its operand is sunk. To avoid searching | ||||||||
1731 | // for DBG_VALUEs later, record them when they're encountered. | ||||||||
1732 | if (MI->isDebugValue()) { | ||||||||
1733 | SmallDenseMap<MCRegister, SmallVector<unsigned, 2>, 4> MIUnits; | ||||||||
1734 | bool IsValid = true; | ||||||||
1735 | for (MachineOperand &MO : MI->debug_operands()) { | ||||||||
1736 | if (MO.isReg() && Register::isPhysicalRegister(MO.getReg())) { | ||||||||
1737 | // Bail if we can already tell the sink would be rejected, rather | ||||||||
1738 | // than needlessly accumulating lots of DBG_VALUEs. | ||||||||
1739 | if (hasRegisterDependency(MI, UsedOpsInCopy, DefedRegsInCopy, | ||||||||
1740 | ModifiedRegUnits, UsedRegUnits)) { | ||||||||
1741 | IsValid = false; | ||||||||
1742 | break; | ||||||||
1743 | } | ||||||||
1744 | |||||||||
1745 | // Record debug use of each reg unit. | ||||||||
1746 | SmallSet<MCRegister, 4> RegUnits = getRegUnits(MO.getReg(), TRI); | ||||||||
1747 | for (MCRegister Reg : RegUnits) | ||||||||
1748 | MIUnits[Reg].push_back(MO.getReg()); | ||||||||
1749 | } | ||||||||
1750 | } | ||||||||
1751 | if (IsValid) { | ||||||||
1752 | for (auto RegOps : MIUnits) | ||||||||
1753 | SeenDbgInstrs[RegOps.first].push_back({MI, RegOps.second}); | ||||||||
1754 | } | ||||||||
1755 | continue; | ||||||||
1756 | } | ||||||||
1757 | |||||||||
1758 | if (MI->isDebugOrPseudoInstr()) | ||||||||
1759 | continue; | ||||||||
1760 | |||||||||
1761 | // Do not move any instruction across function call. | ||||||||
1762 | if (MI->isCall()) | ||||||||
1763 | return false; | ||||||||
1764 | |||||||||
1765 | if (!MI->isCopy() || !MI->getOperand(0).isRenamable()) { | ||||||||
1766 | LiveRegUnits::accumulateUsedDefed(*MI, ModifiedRegUnits, UsedRegUnits, | ||||||||
1767 | TRI); | ||||||||
1768 | continue; | ||||||||
1769 | } | ||||||||
1770 | |||||||||
1771 | // Don't sink the COPY if it would violate a register dependency. | ||||||||
1772 | if (hasRegisterDependency(MI, UsedOpsInCopy, DefedRegsInCopy, | ||||||||
1773 | ModifiedRegUnits, UsedRegUnits)) { | ||||||||
1774 | LiveRegUnits::accumulateUsedDefed(*MI, ModifiedRegUnits, UsedRegUnits, | ||||||||
1775 | TRI); | ||||||||
1776 | continue; | ||||||||
1777 | } | ||||||||
1778 | assert((!UsedOpsInCopy.empty() && !DefedRegsInCopy.empty()) &&((void)0) | ||||||||
1779 | "Unexpect SrcReg or DefReg")((void)0); | ||||||||
1780 | MachineBasicBlock *SuccBB = | ||||||||
1781 | getSingleLiveInSuccBB(CurBB, SinkableBBs, DefedRegsInCopy, TRI); | ||||||||
1782 | // Don't sink if we cannot find a single sinkable successor in which Reg | ||||||||
1783 | // is live-in. | ||||||||
1784 | if (!SuccBB) { | ||||||||
1785 | LiveRegUnits::accumulateUsedDefed(*MI, ModifiedRegUnits, UsedRegUnits, | ||||||||
1786 | TRI); | ||||||||
1787 | continue; | ||||||||
1788 | } | ||||||||
1789 | assert((SuccBB->pred_size() == 1 && *SuccBB->pred_begin() == &CurBB) &&((void)0) | ||||||||
1790 | "Unexpected predecessor")((void)0); | ||||||||
1791 | |||||||||
1792 | // Collect DBG_VALUEs that must sink with this copy. We've previously | ||||||||
1793 | // recorded which reg units that DBG_VALUEs read, if this instruction | ||||||||
1794 | // writes any of those units then the corresponding DBG_VALUEs must sink. | ||||||||
1795 | MapVector<MachineInstr *, MIRegs::second_type> DbgValsToSinkMap; | ||||||||
1796 | for (auto &MO : MI->operands()) { | ||||||||
1797 | if (!MO.isReg() || !MO.isDef()) | ||||||||
1798 | continue; | ||||||||
1799 | |||||||||
1800 | SmallSet<MCRegister, 4> Units = getRegUnits(MO.getReg(), TRI); | ||||||||
1801 | for (MCRegister Reg : Units) { | ||||||||
1802 | for (auto MIRegs : SeenDbgInstrs.lookup(Reg)) { | ||||||||
1803 | auto &Regs = DbgValsToSinkMap[MIRegs.first]; | ||||||||
1804 | for (unsigned Reg : MIRegs.second) | ||||||||
1805 | Regs.push_back(Reg); | ||||||||
1806 | } | ||||||||
1807 | } | ||||||||
1808 | } | ||||||||
1809 | SmallVector<MIRegs, 4> DbgValsToSink(DbgValsToSinkMap.begin(), | ||||||||
1810 | DbgValsToSinkMap.end()); | ||||||||
1811 | |||||||||
1812 | // Clear the kill flag if SrcReg is killed between MI and the end of the | ||||||||
1813 | // block. | ||||||||
1814 | clearKillFlags(MI, CurBB, UsedOpsInCopy, UsedRegUnits, TRI); | ||||||||
1815 | MachineBasicBlock::iterator InsertPos = SuccBB->getFirstNonPHI(); | ||||||||
1816 | performSink(*MI, *SuccBB, InsertPos, DbgValsToSink); | ||||||||
1817 | updateLiveIn(MI, SuccBB, UsedOpsInCopy, DefedRegsInCopy); | ||||||||
1818 | |||||||||
1819 | Changed = true; | ||||||||
1820 | ++NumPostRACopySink; | ||||||||
1821 | } | ||||||||
1822 | return Changed; | ||||||||
1823 | } | ||||||||
1824 | |||||||||
1825 | bool PostRAMachineSinking::runOnMachineFunction(MachineFunction &MF) { | ||||||||
1826 | if (skipFunction(MF.getFunction())) | ||||||||
1827 | return false; | ||||||||
1828 | |||||||||
1829 | bool Changed = false; | ||||||||
1830 | const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo(); | ||||||||
1831 | const TargetInstrInfo *TII = MF.getSubtarget().getInstrInfo(); | ||||||||
1832 | |||||||||
1833 | ModifiedRegUnits.init(*TRI); | ||||||||
1834 | UsedRegUnits.init(*TRI); | ||||||||
1835 | for (auto &BB : MF) | ||||||||
1836 | Changed |= tryToSinkCopy(BB, MF, TRI, TII); | ||||||||
1837 | |||||||||
1838 | return Changed; | ||||||||
1839 | } |
1 | //==- llvm/CodeGen/MachineDominators.h - Machine Dom Calculation -*- C++ -*-==// |
2 | // |
3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
4 | // See https://llvm.org/LICENSE.txt for license information. |
5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
6 | // |
7 | //===----------------------------------------------------------------------===// |
8 | // |
9 | // This file defines classes mirroring those in llvm/Analysis/Dominators.h, |
10 | // but for target-specific code rather than target-independent IR. |
11 | // |
12 | //===----------------------------------------------------------------------===// |
13 | |
14 | #ifndef LLVM_CODEGEN_MACHINEDOMINATORS_H |
15 | #define LLVM_CODEGEN_MACHINEDOMINATORS_H |
16 | |
17 | #include "llvm/ADT/SmallSet.h" |
18 | #include "llvm/ADT/SmallVector.h" |
19 | #include "llvm/CodeGen/MachineBasicBlock.h" |
20 | #include "llvm/CodeGen/MachineFunctionPass.h" |
21 | #include "llvm/CodeGen/MachineInstr.h" |
22 | #include "llvm/Support/GenericDomTree.h" |
23 | #include "llvm/Support/GenericDomTreeConstruction.h" |
24 | #include <cassert> |
25 | #include <memory> |
26 | |
27 | namespace llvm { |
28 | |
29 | template <> |
30 | inline void DominatorTreeBase<MachineBasicBlock, false>::addRoot( |
31 | MachineBasicBlock *MBB) { |
32 | this->Roots.push_back(MBB); |
33 | } |
34 | |
35 | extern template class DomTreeNodeBase<MachineBasicBlock>; |
36 | extern template class DominatorTreeBase<MachineBasicBlock, false>; // DomTree |
37 | extern template class DominatorTreeBase<MachineBasicBlock, true>; // PostDomTree |
38 | |
39 | using MachineDomTreeNode = DomTreeNodeBase<MachineBasicBlock>; |
40 | |
41 | //===------------------------------------- |
42 | /// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to |
43 | /// compute a normal dominator tree. |
44 | /// |
45 | class MachineDominatorTree : public MachineFunctionPass { |
46 | using DomTreeT = DomTreeBase<MachineBasicBlock>; |
47 | |
48 | /// Helper structure used to hold all the basic blocks |
49 | /// involved in the split of a critical edge. |
50 | struct CriticalEdge { |
51 | MachineBasicBlock *FromBB; |
52 | MachineBasicBlock *ToBB; |
53 | MachineBasicBlock *NewBB; |
54 | }; |
55 | |
56 | /// Pile up all the critical edges to be split. |
57 | /// The splitting of a critical edge is local and thus, it is possible |
58 | /// to apply several of those changes at the same time. |
59 | mutable SmallVector<CriticalEdge, 32> CriticalEdgesToSplit; |
60 | |
61 | /// Remember all the basic blocks that are inserted during |
62 | /// edge splitting. |
63 | /// Invariant: NewBBs == all the basic blocks contained in the NewBB |
64 | /// field of all the elements of CriticalEdgesToSplit. |
65 | /// I.e., forall elt in CriticalEdgesToSplit, it exists BB in NewBBs |
66 | /// such as BB == elt.NewBB. |
67 | mutable SmallSet<MachineBasicBlock *, 32> NewBBs; |
68 | |
69 | /// The DominatorTreeBase that is used to compute a normal dominator tree. |
70 | std::unique_ptr<DomTreeT> DT; |
71 | |
72 | /// Apply all the recorded critical edges to the DT. |
73 | /// This updates the underlying DT information in a way that uses |
74 | /// the fast query path of DT as much as possible. |
75 | /// |
76 | /// \post CriticalEdgesToSplit.empty(). |
77 | void applySplitCriticalEdges() const; |
78 | |
79 | public: |
80 | static char ID; // Pass ID, replacement for typeid |
81 | |
82 | MachineDominatorTree(); |
83 | explicit MachineDominatorTree(MachineFunction &MF) : MachineFunctionPass(ID) { |
84 | calculate(MF); |
85 | } |
86 | |
87 | DomTreeT &getBase() { |
88 | if (!DT) DT.reset(new DomTreeT()); |
89 | applySplitCriticalEdges(); |
90 | return *DT; |
91 | } |
92 | |
93 | void getAnalysisUsage(AnalysisUsage &AU) const override; |
94 | |
95 | MachineBasicBlock *getRoot() const { |
96 | applySplitCriticalEdges(); |
97 | return DT->getRoot(); |
98 | } |
99 | |
100 | MachineDomTreeNode *getRootNode() const { |
101 | applySplitCriticalEdges(); |
102 | return DT->getRootNode(); |
103 | } |
104 | |
105 | bool runOnMachineFunction(MachineFunction &F) override; |
106 | |
107 | void calculate(MachineFunction &F); |
108 | |
109 | bool dominates(const MachineDomTreeNode *A, |
110 | const MachineDomTreeNode *B) const { |
111 | applySplitCriticalEdges(); |
112 | return DT->dominates(A, B); |
113 | } |
114 | |
115 | bool dominates(const MachineBasicBlock *A, const MachineBasicBlock *B) const { |
116 | applySplitCriticalEdges(); |
117 | return DT->dominates(A, B); |
118 | } |
119 | |
120 | // dominates - Return true if A dominates B. This performs the |
121 | // special checks necessary if A and B are in the same basic block. |
122 | bool dominates(const MachineInstr *A, const MachineInstr *B) const { |
123 | applySplitCriticalEdges(); |
124 | const MachineBasicBlock *BBA = A->getParent(), *BBB = B->getParent(); |
125 | if (BBA != BBB) return DT->dominates(BBA, BBB); |
126 | |
127 | // Loop through the basic block until we find A or B. |
128 | MachineBasicBlock::const_iterator I = BBA->begin(); |
129 | for (; &*I != A && &*I != B; ++I) |
130 | /*empty*/ ; |
131 | |
132 | return &*I == A; |
133 | } |
134 | |
135 | bool properlyDominates(const MachineDomTreeNode *A, |
136 | const MachineDomTreeNode *B) const { |
137 | applySplitCriticalEdges(); |
138 | return DT->properlyDominates(A, B); |
139 | } |
140 | |
141 | bool properlyDominates(const MachineBasicBlock *A, |
142 | const MachineBasicBlock *B) const { |
143 | applySplitCriticalEdges(); |
144 | return DT->properlyDominates(A, B); |
145 | } |
146 | |
147 | /// findNearestCommonDominator - Find nearest common dominator basic block |
148 | /// for basic block A and B. If there is no such block then return NULL. |
149 | MachineBasicBlock *findNearestCommonDominator(MachineBasicBlock *A, |
150 | MachineBasicBlock *B) { |
151 | applySplitCriticalEdges(); |
152 | return DT->findNearestCommonDominator(A, B); |
153 | } |
154 | |
155 | MachineDomTreeNode *operator[](MachineBasicBlock *BB) const { |
156 | applySplitCriticalEdges(); |
157 | return DT->getNode(BB); |
158 | } |
159 | |
160 | /// getNode - return the (Post)DominatorTree node for the specified basic |
161 | /// block. This is the same as using operator[] on this class. |
162 | /// |
163 | MachineDomTreeNode *getNode(MachineBasicBlock *BB) const { |
164 | applySplitCriticalEdges(); |
165 | return DT->getNode(BB); |
166 | } |
167 | |
168 | /// addNewBlock - Add a new node to the dominator tree information. This |
169 | /// creates a new node as a child of DomBB dominator node,linking it into |
170 | /// the children list of the immediate dominator. |
171 | MachineDomTreeNode *addNewBlock(MachineBasicBlock *BB, |
172 | MachineBasicBlock *DomBB) { |
173 | applySplitCriticalEdges(); |
174 | return DT->addNewBlock(BB, DomBB); |
175 | } |
176 | |
177 | /// changeImmediateDominator - This method is used to update the dominator |
178 | /// tree information when a node's immediate dominator changes. |
179 | /// |
180 | void changeImmediateDominator(MachineBasicBlock *N, |
181 | MachineBasicBlock *NewIDom) { |
182 | applySplitCriticalEdges(); |
183 | DT->changeImmediateDominator(N, NewIDom); |
184 | } |
185 | |
186 | void changeImmediateDominator(MachineDomTreeNode *N, |
187 | MachineDomTreeNode *NewIDom) { |
188 | applySplitCriticalEdges(); |
189 | DT->changeImmediateDominator(N, NewIDom); |
190 | } |
191 | |
192 | /// eraseNode - Removes a node from the dominator tree. Block must not |
193 | /// dominate any other blocks. Removes node from its immediate dominator's |
194 | /// children list. Deletes dominator node associated with basic block BB. |
195 | void eraseNode(MachineBasicBlock *BB) { |
196 | applySplitCriticalEdges(); |
197 | DT->eraseNode(BB); |
198 | } |
199 | |
200 | /// splitBlock - BB is split and now it has one successor. Update dominator |
201 | /// tree to reflect this change. |
202 | void splitBlock(MachineBasicBlock* NewBB) { |
203 | applySplitCriticalEdges(); |
204 | DT->splitBlock(NewBB); |
205 | } |
206 | |
207 | /// isReachableFromEntry - Return true if A is dominated by the entry |
208 | /// block of the function containing it. |
209 | bool isReachableFromEntry(const MachineBasicBlock *A) { |
210 | applySplitCriticalEdges(); |
211 | return DT->isReachableFromEntry(A); |
212 | } |
213 | |
214 | void releaseMemory() override; |
215 | |
216 | void verifyAnalysis() const override; |
217 | |
218 | void print(raw_ostream &OS, const Module*) const override; |
219 | |
220 | /// Record that the critical edge (FromBB, ToBB) has been |
221 | /// split with NewBB. |
222 | /// This is best to use this method instead of directly update the |
223 | /// underlying information, because this helps mitigating the |
224 | /// number of time the DT information is invalidated. |
225 | /// |
226 | /// \note Do not use this method with regular edges. |
227 | /// |
228 | /// \note To benefit from the compile time improvement incurred by this |
229 | /// method, the users of this method have to limit the queries to the DT |
230 | /// interface between two edges splitting. In other words, they have to |
231 | /// pack the splitting of critical edges as much as possible. |
232 | void recordSplitCriticalEdge(MachineBasicBlock *FromBB, |
233 | MachineBasicBlock *ToBB, |
234 | MachineBasicBlock *NewBB) { |
235 | bool Inserted = NewBBs.insert(NewBB).second; |
236 | (void)Inserted; |
237 | assert(Inserted &&((void)0) |
238 | "A basic block inserted via edge splitting cannot appear twice")((void)0); |
239 | CriticalEdgesToSplit.push_back({FromBB, ToBB, NewBB}); |
240 | } |
241 | }; |
242 | |
243 | //===------------------------------------- |
244 | /// DominatorTree GraphTraits specialization so the DominatorTree can be |
245 | /// iterable by generic graph iterators. |
246 | /// |
247 | |
248 | template <class Node, class ChildIterator> |
249 | struct MachineDomTreeGraphTraitsBase { |
250 | using NodeRef = Node *; |
251 | using ChildIteratorType = ChildIterator; |
252 | |
253 | static NodeRef getEntryNode(NodeRef N) { return N; } |
254 | static ChildIteratorType child_begin(NodeRef N) { return N->begin(); } |
255 | static ChildIteratorType child_end(NodeRef N) { return N->end(); } |
256 | }; |
257 | |
258 | template <class T> struct GraphTraits; |
259 | |
260 | template <> |
261 | struct GraphTraits<MachineDomTreeNode *> |
262 | : public MachineDomTreeGraphTraitsBase<MachineDomTreeNode, |
263 | MachineDomTreeNode::const_iterator> { |
264 | }; |
265 | |
266 | template <> |
267 | struct GraphTraits<const MachineDomTreeNode *> |
268 | : public MachineDomTreeGraphTraitsBase<const MachineDomTreeNode, |
269 | MachineDomTreeNode::const_iterator> { |
270 | }; |
271 | |
272 | template <> struct GraphTraits<MachineDominatorTree*> |
273 | : public GraphTraits<MachineDomTreeNode *> { |
274 | static NodeRef getEntryNode(MachineDominatorTree *DT) { |
275 | return DT->getRootNode(); |
276 | } |
277 | }; |
278 | |
279 | } // end namespace llvm |
280 | |
281 | #endif // LLVM_CODEGEN_MACHINEDOMINATORS_H |
1 | //===- GenericDomTree.h - Generic dominator trees for graphs ----*- C++ -*-===// | |||
2 | // | |||
3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. | |||
4 | // See https://llvm.org/LICENSE.txt for license information. | |||
5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception | |||
6 | // | |||
7 | //===----------------------------------------------------------------------===// | |||
8 | /// \file | |||
9 | /// | |||
10 | /// This file defines a set of templates that efficiently compute a dominator | |||
11 | /// tree over a generic graph. This is used typically in LLVM for fast | |||
12 | /// dominance queries on the CFG, but is fully generic w.r.t. the underlying | |||
13 | /// graph types. | |||
14 | /// | |||
15 | /// Unlike ADT/* graph algorithms, generic dominator tree has more requirements | |||
16 | /// on the graph's NodeRef. The NodeRef should be a pointer and, | |||
17 | /// NodeRef->getParent() must return the parent node that is also a pointer. | |||
18 | /// | |||
19 | /// FIXME: Maybe GenericDomTree needs a TreeTraits, instead of GraphTraits. | |||
20 | /// | |||
21 | //===----------------------------------------------------------------------===// | |||
22 | ||||
23 | #ifndef LLVM_SUPPORT_GENERICDOMTREE_H | |||
24 | #define LLVM_SUPPORT_GENERICDOMTREE_H | |||
25 | ||||
26 | #include "llvm/ADT/DenseMap.h" | |||
27 | #include "llvm/ADT/GraphTraits.h" | |||
28 | #include "llvm/ADT/STLExtras.h" | |||
29 | #include "llvm/ADT/SmallPtrSet.h" | |||
30 | #include "llvm/ADT/SmallVector.h" | |||
31 | #include "llvm/Support/CFGDiff.h" | |||
32 | #include "llvm/Support/CFGUpdate.h" | |||
33 | #include "llvm/Support/raw_ostream.h" | |||
34 | #include <algorithm> | |||
35 | #include <cassert> | |||
36 | #include <cstddef> | |||
37 | #include <iterator> | |||
38 | #include <memory> | |||
39 | #include <type_traits> | |||
40 | #include <utility> | |||
41 | ||||
42 | namespace llvm { | |||
43 | ||||
44 | template <typename NodeT, bool IsPostDom> | |||
45 | class DominatorTreeBase; | |||
46 | ||||
47 | namespace DomTreeBuilder { | |||
48 | template <typename DomTreeT> | |||
49 | struct SemiNCAInfo; | |||
50 | } // namespace DomTreeBuilder | |||
51 | ||||
52 | /// Base class for the actual dominator tree node. | |||
53 | template <class NodeT> class DomTreeNodeBase { | |||
54 | friend class PostDominatorTree; | |||
55 | friend class DominatorTreeBase<NodeT, false>; | |||
56 | friend class DominatorTreeBase<NodeT, true>; | |||
57 | friend struct DomTreeBuilder::SemiNCAInfo<DominatorTreeBase<NodeT, false>>; | |||
58 | friend struct DomTreeBuilder::SemiNCAInfo<DominatorTreeBase<NodeT, true>>; | |||
59 | ||||
60 | NodeT *TheBB; | |||
61 | DomTreeNodeBase *IDom; | |||
62 | unsigned Level; | |||
63 | SmallVector<DomTreeNodeBase *, 4> Children; | |||
64 | mutable unsigned DFSNumIn = ~0; | |||
65 | mutable unsigned DFSNumOut = ~0; | |||
66 | ||||
67 | public: | |||
68 | DomTreeNodeBase(NodeT *BB, DomTreeNodeBase *iDom) | |||
69 | : TheBB(BB), IDom(iDom), Level(IDom ? IDom->Level + 1 : 0) {} | |||
70 | ||||
71 | using iterator = typename SmallVector<DomTreeNodeBase *, 4>::iterator; | |||
72 | using const_iterator = | |||
73 | typename SmallVector<DomTreeNodeBase *, 4>::const_iterator; | |||
74 | ||||
75 | iterator begin() { return Children.begin(); } | |||
76 | iterator end() { return Children.end(); } | |||
77 | const_iterator begin() const { return Children.begin(); } | |||
78 | const_iterator end() const { return Children.end(); } | |||
79 | ||||
80 | DomTreeNodeBase *const &back() const { return Children.back(); } | |||
81 | DomTreeNodeBase *&back() { return Children.back(); } | |||
82 | ||||
83 | iterator_range<iterator> children() { return make_range(begin(), end()); } | |||
84 | iterator_range<const_iterator> children() const { | |||
85 | return make_range(begin(), end()); | |||
86 | } | |||
87 | ||||
88 | NodeT *getBlock() const { return TheBB; } | |||
89 | DomTreeNodeBase *getIDom() const { return IDom; } | |||
90 | unsigned getLevel() const { return Level; } | |||
91 | ||||
92 | std::unique_ptr<DomTreeNodeBase> addChild( | |||
93 | std::unique_ptr<DomTreeNodeBase> C) { | |||
94 | Children.push_back(C.get()); | |||
95 | return C; | |||
96 | } | |||
97 | ||||
98 | bool isLeaf() const { return Children.empty(); } | |||
99 | size_t getNumChildren() const { return Children.size(); } | |||
100 | ||||
101 | void clearAllChildren() { Children.clear(); } | |||
102 | ||||
103 | bool compare(const DomTreeNodeBase *Other) const { | |||
104 | if (getNumChildren() != Other->getNumChildren()) | |||
105 | return true; | |||
106 | ||||
107 | if (Level != Other->Level) return true; | |||
108 | ||||
109 | SmallPtrSet<const NodeT *, 4> OtherChildren; | |||
110 | for (const DomTreeNodeBase *I : *Other) { | |||
111 | const NodeT *Nd = I->getBlock(); | |||
112 | OtherChildren.insert(Nd); | |||
113 | } | |||
114 | ||||
115 | for (const DomTreeNodeBase *I : *this) { | |||
116 | const NodeT *N = I->getBlock(); | |||
117 | if (OtherChildren.count(N) == 0) | |||
118 | return true; | |||
119 | } | |||
120 | return false; | |||
121 | } | |||
122 | ||||
123 | void setIDom(DomTreeNodeBase *NewIDom) { | |||
124 | assert(IDom && "No immediate dominator?")((void)0); | |||
125 | if (IDom == NewIDom) return; | |||
126 | ||||
127 | auto I = find(IDom->Children, this); | |||
128 | assert(I != IDom->Children.end() &&((void)0) | |||
129 | "Not in immediate dominator children set!")((void)0); | |||
130 | // I am no longer your child... | |||
131 | IDom->Children.erase(I); | |||
132 | ||||
133 | // Switch to new dominator | |||
134 | IDom = NewIDom; | |||
135 | IDom->Children.push_back(this); | |||
136 | ||||
137 | UpdateLevel(); | |||
138 | } | |||
139 | ||||
140 | /// getDFSNumIn/getDFSNumOut - These return the DFS visitation order for nodes | |||
141 | /// in the dominator tree. They are only guaranteed valid if | |||
142 | /// updateDFSNumbers() has been called. | |||
143 | unsigned getDFSNumIn() const { return DFSNumIn; } | |||
144 | unsigned getDFSNumOut() const { return DFSNumOut; } | |||
145 | ||||
146 | private: | |||
147 | // Return true if this node is dominated by other. Use this only if DFS info | |||
148 | // is valid. | |||
149 | bool DominatedBy(const DomTreeNodeBase *other) const { | |||
150 | return this->DFSNumIn >= other->DFSNumIn && | |||
151 | this->DFSNumOut <= other->DFSNumOut; | |||
152 | } | |||
153 | ||||
154 | void UpdateLevel() { | |||
155 | assert(IDom)((void)0); | |||
156 | if (Level == IDom->Level + 1) return; | |||
157 | ||||
158 | SmallVector<DomTreeNodeBase *, 64> WorkStack = {this}; | |||
159 | ||||
160 | while (!WorkStack.empty()) { | |||
161 | DomTreeNodeBase *Current = WorkStack.pop_back_val(); | |||
162 | Current->Level = Current->IDom->Level + 1; | |||
163 | ||||
164 | for (DomTreeNodeBase *C : *Current) { | |||
165 | assert(C->IDom)((void)0); | |||
166 | if (C->Level != C->IDom->Level + 1) WorkStack.push_back(C); | |||
167 | } | |||
168 | } | |||
169 | } | |||
170 | }; | |||
171 | ||||
172 | template <class NodeT> | |||
173 | raw_ostream &operator<<(raw_ostream &O, const DomTreeNodeBase<NodeT> *Node) { | |||
174 | if (Node->getBlock()) | |||
175 | Node->getBlock()->printAsOperand(O, false); | |||
176 | else | |||
177 | O << " <<exit node>>"; | |||
178 | ||||
179 | O << " {" << Node->getDFSNumIn() << "," << Node->getDFSNumOut() << "} [" | |||
180 | << Node->getLevel() << "]\n"; | |||
181 | ||||
182 | return O; | |||
183 | } | |||
184 | ||||
185 | template <class NodeT> | |||
186 | void PrintDomTree(const DomTreeNodeBase<NodeT> *N, raw_ostream &O, | |||
187 | unsigned Lev) { | |||
188 | O.indent(2 * Lev) << "[" << Lev << "] " << N; | |||
189 | for (typename DomTreeNodeBase<NodeT>::const_iterator I = N->begin(), | |||
190 | E = N->end(); | |||
191 | I != E; ++I) | |||
192 | PrintDomTree<NodeT>(*I, O, Lev + 1); | |||
193 | } | |||
194 | ||||
195 | namespace DomTreeBuilder { | |||
196 | // The routines below are provided in a separate header but referenced here. | |||
197 | template <typename DomTreeT> | |||
198 | void Calculate(DomTreeT &DT); | |||
199 | ||||
200 | template <typename DomTreeT> | |||
201 | void CalculateWithUpdates(DomTreeT &DT, | |||
202 | ArrayRef<typename DomTreeT::UpdateType> Updates); | |||
203 | ||||
204 | template <typename DomTreeT> | |||
205 | void InsertEdge(DomTreeT &DT, typename DomTreeT::NodePtr From, | |||
206 | typename DomTreeT::NodePtr To); | |||
207 | ||||
208 | template <typename DomTreeT> | |||
209 | void DeleteEdge(DomTreeT &DT, typename DomTreeT::NodePtr From, | |||
210 | typename DomTreeT::NodePtr To); | |||
211 | ||||
212 | template <typename DomTreeT> | |||
213 | void ApplyUpdates(DomTreeT &DT, | |||
214 | GraphDiff<typename DomTreeT::NodePtr, | |||
215 | DomTreeT::IsPostDominator> &PreViewCFG, | |||
216 | GraphDiff<typename DomTreeT::NodePtr, | |||
217 | DomTreeT::IsPostDominator> *PostViewCFG); | |||
218 | ||||
219 | template <typename DomTreeT> | |||
220 | bool Verify(const DomTreeT &DT, typename DomTreeT::VerificationLevel VL); | |||
221 | } // namespace DomTreeBuilder | |||
222 | ||||
223 | /// Core dominator tree base class. | |||
224 | /// | |||
225 | /// This class is a generic template over graph nodes. It is instantiated for | |||
226 | /// various graphs in the LLVM IR or in the code generator. | |||
227 | template <typename NodeT, bool IsPostDom> | |||
228 | class DominatorTreeBase { | |||
229 | public: | |||
230 | static_assert(std::is_pointer<typename GraphTraits<NodeT *>::NodeRef>::value, | |||
231 | "Currently DominatorTreeBase supports only pointer nodes"); | |||
232 | using NodeType = NodeT; | |||
233 | using NodePtr = NodeT *; | |||
234 | using ParentPtr = decltype(std::declval<NodeT *>()->getParent()); | |||
235 | static_assert(std::is_pointer<ParentPtr>::value, | |||
236 | "Currently NodeT's parent must be a pointer type"); | |||
237 | using ParentType = std::remove_pointer_t<ParentPtr>; | |||
238 | static constexpr bool IsPostDominator = IsPostDom; | |||
239 | ||||
240 | using UpdateType = cfg::Update<NodePtr>; | |||
241 | using UpdateKind = cfg::UpdateKind; | |||
242 | static constexpr UpdateKind Insert = UpdateKind::Insert; | |||
243 | static constexpr UpdateKind Delete = UpdateKind::Delete; | |||
244 | ||||
245 | enum class VerificationLevel { Fast, Basic, Full }; | |||
246 | ||||
247 | protected: | |||
248 | // Dominators always have a single root, postdominators can have more. | |||
249 | SmallVector<NodeT *, IsPostDom ? 4 : 1> Roots; | |||
250 | ||||
251 | using DomTreeNodeMapType = | |||
252 | DenseMap<NodeT *, std::unique_ptr<DomTreeNodeBase<NodeT>>>; | |||
253 | DomTreeNodeMapType DomTreeNodes; | |||
254 | DomTreeNodeBase<NodeT> *RootNode = nullptr; | |||
255 | ParentPtr Parent = nullptr; | |||
256 | ||||
257 | mutable bool DFSInfoValid = false; | |||
258 | mutable unsigned int SlowQueries = 0; | |||
259 | ||||
260 | friend struct DomTreeBuilder::SemiNCAInfo<DominatorTreeBase>; | |||
261 | ||||
262 | public: | |||
263 | DominatorTreeBase() {} | |||
264 | ||||
265 | DominatorTreeBase(DominatorTreeBase &&Arg) | |||
266 | : Roots(std::move(Arg.Roots)), | |||
267 | DomTreeNodes(std::move(Arg.DomTreeNodes)), | |||
268 | RootNode(Arg.RootNode), | |||
269 | Parent(Arg.Parent), | |||
270 | DFSInfoValid(Arg.DFSInfoValid), | |||
271 | SlowQueries(Arg.SlowQueries) { | |||
272 | Arg.wipe(); | |||
273 | } | |||
274 | ||||
275 | DominatorTreeBase &operator=(DominatorTreeBase &&RHS) { | |||
276 | Roots = std::move(RHS.Roots); | |||
277 | DomTreeNodes = std::move(RHS.DomTreeNodes); | |||
278 | RootNode = RHS.RootNode; | |||
279 | Parent = RHS.Parent; | |||
280 | DFSInfoValid = RHS.DFSInfoValid; | |||
281 | SlowQueries = RHS.SlowQueries; | |||
282 | RHS.wipe(); | |||
283 | return *this; | |||
284 | } | |||
285 | ||||
286 | DominatorTreeBase(const DominatorTreeBase &) = delete; | |||
287 | DominatorTreeBase &operator=(const DominatorTreeBase &) = delete; | |||
288 | ||||
289 | /// Iteration over roots. | |||
290 | /// | |||
291 | /// This may include multiple blocks if we are computing post dominators. | |||
292 | /// For forward dominators, this will always be a single block (the entry | |||
293 | /// block). | |||
294 | using root_iterator = typename SmallVectorImpl<NodeT *>::iterator; | |||
295 | using const_root_iterator = typename SmallVectorImpl<NodeT *>::const_iterator; | |||
296 | ||||
297 | root_iterator root_begin() { return Roots.begin(); } | |||
298 | const_root_iterator root_begin() const { return Roots.begin(); } | |||
299 | root_iterator root_end() { return Roots.end(); } | |||
300 | const_root_iterator root_end() const { return Roots.end(); } | |||
301 | ||||
302 | size_t root_size() const { return Roots.size(); } | |||
303 | ||||
304 | iterator_range<root_iterator> roots() { | |||
305 | return make_range(root_begin(), root_end()); | |||
306 | } | |||
307 | iterator_range<const_root_iterator> roots() const { | |||
308 | return make_range(root_begin(), root_end()); | |||
309 | } | |||
310 | ||||
311 | /// isPostDominator - Returns true if analysis based of postdoms | |||
312 | /// | |||
313 | bool isPostDominator() const { return IsPostDominator; } | |||
314 | ||||
315 | /// compare - Return false if the other dominator tree base matches this | |||
316 | /// dominator tree base. Otherwise return true. | |||
317 | bool compare(const DominatorTreeBase &Other) const { | |||
318 | if (Parent != Other.Parent) return true; | |||
319 | ||||
320 | if (Roots.size() != Other.Roots.size()) | |||
321 | return true; | |||
322 | ||||
323 | if (!std::is_permutation(Roots.begin(), Roots.end(), Other.Roots.begin())) | |||
324 | return true; | |||
325 | ||||
326 | const DomTreeNodeMapType &OtherDomTreeNodes = Other.DomTreeNodes; | |||
327 | if (DomTreeNodes.size() != OtherDomTreeNodes.size()) | |||
328 | return true; | |||
329 | ||||
330 | for (const auto &DomTreeNode : DomTreeNodes) { | |||
331 | NodeT *BB = DomTreeNode.first; | |||
332 | typename DomTreeNodeMapType::const_iterator OI = | |||
333 | OtherDomTreeNodes.find(BB); | |||
334 | if (OI == OtherDomTreeNodes.end()) | |||
335 | return true; | |||
336 | ||||
337 | DomTreeNodeBase<NodeT> &MyNd = *DomTreeNode.second; | |||
338 | DomTreeNodeBase<NodeT> &OtherNd = *OI->second; | |||
339 | ||||
340 | if (MyNd.compare(&OtherNd)) | |||
341 | return true; | |||
342 | } | |||
343 | ||||
344 | return false; | |||
345 | } | |||
346 | ||||
347 | /// getNode - return the (Post)DominatorTree node for the specified basic | |||
348 | /// block. This is the same as using operator[] on this class. The result | |||
349 | /// may (but is not required to) be null for a forward (backwards) | |||
350 | /// statically unreachable block. | |||
351 | DomTreeNodeBase<NodeT> *getNode(const NodeT *BB) const { | |||
352 | auto I = DomTreeNodes.find(BB); | |||
353 | if (I != DomTreeNodes.end()) | |||
354 | return I->second.get(); | |||
355 | return nullptr; | |||
356 | } | |||
357 | ||||
358 | /// See getNode. | |||
359 | DomTreeNodeBase<NodeT> *operator[](const NodeT *BB) const { | |||
360 | return getNode(BB); | |||
361 | } | |||
362 | ||||
363 | /// getRootNode - This returns the entry node for the CFG of the function. If | |||
364 | /// this tree represents the post-dominance relations for a function, however, | |||
365 | /// this root may be a node with the block == NULL. This is the case when | |||
366 | /// there are multiple exit nodes from a particular function. Consumers of | |||
367 | /// post-dominance information must be capable of dealing with this | |||
368 | /// possibility. | |||
369 | /// | |||
370 | DomTreeNodeBase<NodeT> *getRootNode() { return RootNode; } | |||
371 | const DomTreeNodeBase<NodeT> *getRootNode() const { return RootNode; } | |||
372 | ||||
373 | /// Get all nodes dominated by R, including R itself. | |||
374 | void getDescendants(NodeT *R, SmallVectorImpl<NodeT *> &Result) const { | |||
375 | Result.clear(); | |||
376 | const DomTreeNodeBase<NodeT> *RN = getNode(R); | |||
377 | if (!RN) | |||
378 | return; // If R is unreachable, it will not be present in the DOM tree. | |||
379 | SmallVector<const DomTreeNodeBase<NodeT> *, 8> WL; | |||
380 | WL.push_back(RN); | |||
381 | ||||
382 | while (!WL.empty()) { | |||
383 | const DomTreeNodeBase<NodeT> *N = WL.pop_back_val(); | |||
384 | Result.push_back(N->getBlock()); | |||
385 | WL.append(N->begin(), N->end()); | |||
386 | } | |||
387 | } | |||
388 | ||||
389 | /// properlyDominates - Returns true iff A dominates B and A != B. | |||
390 | /// Note that this is not a constant time operation! | |||
391 | /// | |||
392 | bool properlyDominates(const DomTreeNodeBase<NodeT> *A, | |||
393 | const DomTreeNodeBase<NodeT> *B) const { | |||
394 | if (!A || !B) | |||
395 | return false; | |||
396 | if (A == B) | |||
397 | return false; | |||
398 | return dominates(A, B); | |||
399 | } | |||
400 | ||||
401 | bool properlyDominates(const NodeT *A, const NodeT *B) const; | |||
402 | ||||
403 | /// isReachableFromEntry - Return true if A is dominated by the entry | |||
404 | /// block of the function containing it. | |||
405 | bool isReachableFromEntry(const NodeT *A) const { | |||
406 | assert(!this->isPostDominator() &&((void)0) | |||
407 | "This is not implemented for post dominators")((void)0); | |||
408 | return isReachableFromEntry(getNode(const_cast<NodeT *>(A))); | |||
409 | } | |||
410 | ||||
411 | bool isReachableFromEntry(const DomTreeNodeBase<NodeT> *A) const { return A; } | |||
412 | ||||
413 | /// dominates - Returns true iff A dominates B. Note that this is not a | |||
414 | /// constant time operation! | |||
415 | /// | |||
416 | bool dominates(const DomTreeNodeBase<NodeT> *A, | |||
417 | const DomTreeNodeBase<NodeT> *B) const { | |||
418 | // A node trivially dominates itself. | |||
419 | if (B == A) | |||
420 | return true; | |||
421 | ||||
422 | // An unreachable node is dominated by anything. | |||
423 | if (!isReachableFromEntry(B)) | |||
424 | return true; | |||
425 | ||||
426 | // And dominates nothing. | |||
427 | if (!isReachableFromEntry(A)) | |||
428 | return false; | |||
429 | ||||
430 | if (B->getIDom() == A) return true; | |||
431 | ||||
432 | if (A->getIDom() == B) return false; | |||
433 | ||||
434 | // A can only dominate B if it is higher in the tree. | |||
435 | if (A->getLevel() >= B->getLevel()) return false; | |||
436 | ||||
437 | // Compare the result of the tree walk and the dfs numbers, if expensive | |||
438 | // checks are enabled. | |||
439 | #ifdef EXPENSIVE_CHECKS | |||
440 | assert((!DFSInfoValid ||((void)0) | |||
441 | (dominatedBySlowTreeWalk(A, B) == B->DominatedBy(A))) &&((void)0) | |||
442 | "Tree walk disagrees with dfs numbers!")((void)0); | |||
443 | #endif | |||
444 | ||||
445 | if (DFSInfoValid) | |||
446 | return B->DominatedBy(A); | |||
447 | ||||
448 | // If we end up with too many slow queries, just update the | |||
449 | // DFS numbers on the theory that we are going to keep querying. | |||
450 | SlowQueries++; | |||
451 | if (SlowQueries > 32) { | |||
452 | updateDFSNumbers(); | |||
453 | return B->DominatedBy(A); | |||
454 | } | |||
455 | ||||
456 | return dominatedBySlowTreeWalk(A, B); | |||
457 | } | |||
458 | ||||
459 | bool dominates(const NodeT *A, const NodeT *B) const; | |||
460 | ||||
461 | NodeT *getRoot() const { | |||
462 | assert(this->Roots.size() == 1 && "Should always have entry node!")((void)0); | |||
463 | return this->Roots[0]; | |||
464 | } | |||
465 | ||||
466 | /// Find nearest common dominator basic block for basic block A and B. A and B | |||
467 | /// must have tree nodes. | |||
468 | NodeT *findNearestCommonDominator(NodeT *A, NodeT *B) const { | |||
469 | assert(A && B && "Pointers are not valid")((void)0); | |||
470 | assert(A->getParent() == B->getParent() &&((void)0) | |||
471 | "Two blocks are not in same function")((void)0); | |||
472 | ||||
473 | // If either A or B is a entry block then it is nearest common dominator | |||
474 | // (for forward-dominators). | |||
475 | if (!isPostDominator()) { | |||
476 | NodeT &Entry = A->getParent()->front(); | |||
477 | if (A == &Entry || B == &Entry) | |||
478 | return &Entry; | |||
479 | } | |||
480 | ||||
481 | DomTreeNodeBase<NodeT> *NodeA = getNode(A); | |||
482 | DomTreeNodeBase<NodeT> *NodeB = getNode(B); | |||
483 | assert(NodeA && "A must be in the tree")((void)0); | |||
484 | assert(NodeB && "B must be in the tree")((void)0); | |||
485 | ||||
486 | // Use level information to go up the tree until the levels match. Then | |||
487 | // continue going up til we arrive at the same node. | |||
488 | while (NodeA != NodeB) { | |||
489 | if (NodeA->getLevel() < NodeB->getLevel()) std::swap(NodeA, NodeB); | |||
490 | ||||
491 | NodeA = NodeA->IDom; | |||
492 | } | |||
493 | ||||
494 | return NodeA->getBlock(); | |||
| ||||
495 | } | |||
496 | ||||
497 | const NodeT *findNearestCommonDominator(const NodeT *A, | |||
498 | const NodeT *B) const { | |||
499 | // Cast away the const qualifiers here. This is ok since | |||
500 | // const is re-introduced on the return type. | |||
501 | return findNearestCommonDominator(const_cast<NodeT *>(A), | |||
502 | const_cast<NodeT *>(B)); | |||
503 | } | |||
504 | ||||
505 | bool isVirtualRoot(const DomTreeNodeBase<NodeT> *A) const { | |||
506 | return isPostDominator() && !A->getBlock(); | |||
507 | } | |||
508 | ||||
509 | //===--------------------------------------------------------------------===// | |||
510 | // API to update (Post)DominatorTree information based on modifications to | |||
511 | // the CFG... | |||
512 | ||||
513 | /// Inform the dominator tree about a sequence of CFG edge insertions and | |||
514 | /// deletions and perform a batch update on the tree. | |||
515 | /// | |||
516 | /// This function should be used when there were multiple CFG updates after | |||
517 | /// the last dominator tree update. It takes care of performing the updates | |||
518 | /// in sync with the CFG and optimizes away the redundant operations that | |||
519 | /// cancel each other. | |||
520 | /// The functions expects the sequence of updates to be balanced. Eg.: | |||
521 | /// - {{Insert, A, B}, {Delete, A, B}, {Insert, A, B}} is fine, because | |||
522 | /// logically it results in a single insertions. | |||
523 | /// - {{Insert, A, B}, {Insert, A, B}} is invalid, because it doesn't make | |||
524 | /// sense to insert the same edge twice. | |||
525 | /// | |||
526 | /// What's more, the functions assumes that it's safe to ask every node in the | |||
527 | /// CFG about its children and inverse children. This implies that deletions | |||
528 | /// of CFG edges must not delete the CFG nodes before calling this function. | |||
529 | /// | |||
530 | /// The applyUpdates function can reorder the updates and remove redundant | |||
531 | /// ones internally. The batch updater is also able to detect sequences of | |||
532 | /// zero and exactly one update -- it's optimized to do less work in these | |||
533 | /// cases. | |||
534 | /// | |||
535 | /// Note that for postdominators it automatically takes care of applying | |||
536 | /// updates on reverse edges internally (so there's no need to swap the | |||
537 | /// From and To pointers when constructing DominatorTree::UpdateType). | |||
538 | /// The type of updates is the same for DomTreeBase<T> and PostDomTreeBase<T> | |||
539 | /// with the same template parameter T. | |||
540 | /// | |||
541 | /// \param Updates An unordered sequence of updates to perform. The current | |||
542 | /// CFG and the reverse of these updates provides the pre-view of the CFG. | |||
543 | /// | |||
544 | void applyUpdates(ArrayRef<UpdateType> Updates) { | |||
545 | GraphDiff<NodePtr, IsPostDominator> PreViewCFG( | |||
546 | Updates, /*ReverseApplyUpdates=*/true); | |||
547 | DomTreeBuilder::ApplyUpdates(*this, PreViewCFG, nullptr); | |||
548 | } | |||
549 | ||||
550 | /// \param Updates An unordered sequence of updates to perform. The current | |||
551 | /// CFG and the reverse of these updates provides the pre-view of the CFG. | |||
552 | /// \param PostViewUpdates An unordered sequence of update to perform in order | |||
553 | /// to obtain a post-view of the CFG. The DT will be updated assuming the | |||
554 | /// obtained PostViewCFG is the desired end state. | |||
555 | void applyUpdates(ArrayRef<UpdateType> Updates, | |||
556 | ArrayRef<UpdateType> PostViewUpdates) { | |||
557 | if (Updates.empty()) { | |||
558 | GraphDiff<NodePtr, IsPostDom> PostViewCFG(PostViewUpdates); | |||
559 | DomTreeBuilder::ApplyUpdates(*this, PostViewCFG, &PostViewCFG); | |||
560 | } else { | |||
561 | // PreViewCFG needs to merge Updates and PostViewCFG. The updates in | |||
562 | // Updates need to be reversed, and match the direction in PostViewCFG. | |||
563 | // The PostViewCFG is created with updates reversed (equivalent to changes | |||
564 | // made to the CFG), so the PreViewCFG needs all the updates reverse | |||
565 | // applied. | |||
566 | SmallVector<UpdateType> AllUpdates(Updates.begin(), Updates.end()); | |||
567 | append_range(AllUpdates, PostViewUpdates); | |||
568 | GraphDiff<NodePtr, IsPostDom> PreViewCFG(AllUpdates, | |||
569 | /*ReverseApplyUpdates=*/true); | |||
570 | GraphDiff<NodePtr, IsPostDom> PostViewCFG(PostViewUpdates); | |||
571 | DomTreeBuilder::ApplyUpdates(*this, PreViewCFG, &PostViewCFG); | |||
572 | } | |||
573 | } | |||
574 | ||||
575 | /// Inform the dominator tree about a CFG edge insertion and update the tree. | |||
576 | /// | |||
577 | /// This function has to be called just before or just after making the update | |||
578 | /// on the actual CFG. There cannot be any other updates that the dominator | |||
579 | /// tree doesn't know about. | |||
580 | /// | |||
581 | /// Note that for postdominators it automatically takes care of inserting | |||
582 | /// a reverse edge internally (so there's no need to swap the parameters). | |||
583 | /// | |||
584 | void insertEdge(NodeT *From, NodeT *To) { | |||
585 | assert(From)((void)0); | |||
586 | assert(To)((void)0); | |||
587 | assert(From->getParent() == Parent)((void)0); | |||
588 | assert(To->getParent() == Parent)((void)0); | |||
589 | DomTreeBuilder::InsertEdge(*this, From, To); | |||
590 | } | |||
591 | ||||
592 | /// Inform the dominator tree about a CFG edge deletion and update the tree. | |||
593 | /// | |||
594 | /// This function has to be called just after making the update on the actual | |||
595 | /// CFG. An internal functions checks if the edge doesn't exist in the CFG in | |||
596 | /// DEBUG mode. There cannot be any other updates that the | |||
597 | /// dominator tree doesn't know about. | |||
598 | /// | |||
599 | /// Note that for postdominators it automatically takes care of deleting | |||
600 | /// a reverse edge internally (so there's no need to swap the parameters). | |||
601 | /// | |||
602 | void deleteEdge(NodeT *From, NodeT *To) { | |||
603 | assert(From)((void)0); | |||
604 | assert(To)((void)0); | |||
605 | assert(From->getParent() == Parent)((void)0); | |||
606 | assert(To->getParent() == Parent)((void)0); | |||
607 | DomTreeBuilder::DeleteEdge(*this, From, To); | |||
608 | } | |||
609 | ||||
610 | /// Add a new node to the dominator tree information. | |||
611 | /// | |||
612 | /// This creates a new node as a child of DomBB dominator node, linking it | |||
613 | /// into the children list of the immediate dominator. | |||
614 | /// | |||
615 | /// \param BB New node in CFG. | |||
616 | /// \param DomBB CFG node that is dominator for BB. | |||
617 | /// \returns New dominator tree node that represents new CFG node. | |||
618 | /// | |||
619 | DomTreeNodeBase<NodeT> *addNewBlock(NodeT *BB, NodeT *DomBB) { | |||
620 | assert(getNode(BB) == nullptr && "Block already in dominator tree!")((void)0); | |||
621 | DomTreeNodeBase<NodeT> *IDomNode = getNode(DomBB); | |||
622 | assert(IDomNode && "Not immediate dominator specified for block!")((void)0); | |||
623 | DFSInfoValid = false; | |||
624 | return createChild(BB, IDomNode); | |||
625 | } | |||
626 | ||||
627 | /// Add a new node to the forward dominator tree and make it a new root. | |||
628 | /// | |||
629 | /// \param BB New node in CFG. | |||
630 | /// \returns New dominator tree node that represents new CFG node. | |||
631 | /// | |||
632 | DomTreeNodeBase<NodeT> *setNewRoot(NodeT *BB) { | |||
633 | assert(getNode(BB) == nullptr && "Block already in dominator tree!")((void)0); | |||
634 | assert(!this->isPostDominator() &&((void)0) | |||
635 | "Cannot change root of post-dominator tree")((void)0); | |||
636 | DFSInfoValid = false; | |||
637 | DomTreeNodeBase<NodeT> *NewNode = createNode(BB); | |||
638 | if (Roots.empty()) { | |||
639 | addRoot(BB); | |||
640 | } else { | |||
641 | assert(Roots.size() == 1)((void)0); | |||
642 | NodeT *OldRoot = Roots.front(); | |||
643 | auto &OldNode = DomTreeNodes[OldRoot]; | |||
644 | OldNode = NewNode->addChild(std::move(DomTreeNodes[OldRoot])); | |||
645 | OldNode->IDom = NewNode; | |||
646 | OldNode->UpdateLevel(); | |||
647 | Roots[0] = BB; | |||
648 | } | |||
649 | return RootNode = NewNode; | |||
650 | } | |||
651 | ||||
652 | /// changeImmediateDominator - This method is used to update the dominator | |||
653 | /// tree information when a node's immediate dominator changes. | |||
654 | /// | |||
655 | void changeImmediateDominator(DomTreeNodeBase<NodeT> *N, | |||
656 | DomTreeNodeBase<NodeT> *NewIDom) { | |||
657 | assert(N && NewIDom && "Cannot change null node pointers!")((void)0); | |||
658 | DFSInfoValid = false; | |||
659 | N->setIDom(NewIDom); | |||
660 | } | |||
661 | ||||
662 | void changeImmediateDominator(NodeT *BB, NodeT *NewBB) { | |||
663 | changeImmediateDominator(getNode(BB), getNode(NewBB)); | |||
664 | } | |||
665 | ||||
666 | /// eraseNode - Removes a node from the dominator tree. Block must not | |||
667 | /// dominate any other blocks. Removes node from its immediate dominator's | |||
668 | /// children list. Deletes dominator node associated with basic block BB. | |||
669 | void eraseNode(NodeT *BB) { | |||
670 | DomTreeNodeBase<NodeT> *Node = getNode(BB); | |||
671 | assert(Node && "Removing node that isn't in dominator tree.")((void)0); | |||
672 | assert(Node->isLeaf() && "Node is not a leaf node.")((void)0); | |||
673 | ||||
674 | DFSInfoValid = false; | |||
675 | ||||
676 | // Remove node from immediate dominator's children list. | |||
677 | DomTreeNodeBase<NodeT> *IDom = Node->getIDom(); | |||
678 | if (IDom) { | |||
679 | const auto I = find(IDom->Children, Node); | |||
680 | assert(I != IDom->Children.end() &&((void)0) | |||
681 | "Not in immediate dominator children set!")((void)0); | |||
682 | // I am no longer your child... | |||
683 | IDom->Children.erase(I); | |||
684 | } | |||
685 | ||||
686 | DomTreeNodes.erase(BB); | |||
687 | ||||
688 | if (!IsPostDom) return; | |||
689 | ||||
690 | // Remember to update PostDominatorTree roots. | |||
691 | auto RIt = llvm::find(Roots, BB); | |||
692 | if (RIt != Roots.end()) { | |||
693 | std::swap(*RIt, Roots.back()); | |||
694 | Roots.pop_back(); | |||
695 | } | |||
696 | } | |||
697 | ||||
698 | /// splitBlock - BB is split and now it has one successor. Update dominator | |||
699 | /// tree to reflect this change. | |||
700 | void splitBlock(NodeT *NewBB) { | |||
701 | if (IsPostDominator) | |||
702 | Split<Inverse<NodeT *>>(NewBB); | |||
703 | else | |||
704 | Split<NodeT *>(NewBB); | |||
705 | } | |||
706 | ||||
707 | /// print - Convert to human readable form | |||
708 | /// | |||
709 | void print(raw_ostream &O) const { | |||
710 | O << "=============================--------------------------------\n"; | |||
711 | if (IsPostDominator) | |||
712 | O << "Inorder PostDominator Tree: "; | |||
713 | else | |||
714 | O << "Inorder Dominator Tree: "; | |||
715 | if (!DFSInfoValid) | |||
716 | O << "DFSNumbers invalid: " << SlowQueries << " slow queries."; | |||
717 | O << "\n"; | |||
718 | ||||
719 | // The postdom tree can have a null root if there are no returns. | |||
720 | if (getRootNode()) PrintDomTree<NodeT>(getRootNode(), O, 1); | |||
721 | O << "Roots: "; | |||
722 | for (const NodePtr Block : Roots) { | |||
723 | Block->printAsOperand(O, false); | |||
724 | O << " "; | |||
725 | } | |||
726 | O << "\n"; | |||
727 | } | |||
728 | ||||
729 | public: | |||
730 | /// updateDFSNumbers - Assign In and Out numbers to the nodes while walking | |||
731 | /// dominator tree in dfs order. | |||
732 | void updateDFSNumbers() const { | |||
733 | if (DFSInfoValid) { | |||
734 | SlowQueries = 0; | |||
735 | return; | |||
736 | } | |||
737 | ||||
738 | SmallVector<std::pair<const DomTreeNodeBase<NodeT> *, | |||
739 | typename DomTreeNodeBase<NodeT>::const_iterator>, | |||
740 | 32> WorkStack; | |||
741 | ||||
742 | const DomTreeNodeBase<NodeT> *ThisRoot = getRootNode(); | |||
743 | assert((!Parent || ThisRoot) && "Empty constructed DomTree")((void)0); | |||
744 | if (!ThisRoot) | |||
745 | return; | |||
746 | ||||
747 | // Both dominators and postdominators have a single root node. In the case | |||
748 | // case of PostDominatorTree, this node is a virtual root. | |||
749 | WorkStack.push_back({ThisRoot, ThisRoot->begin()}); | |||
750 | ||||
751 | unsigned DFSNum = 0; | |||
752 | ThisRoot->DFSNumIn = DFSNum++; | |||
753 | ||||
754 | while (!WorkStack.empty()) { | |||
755 | const DomTreeNodeBase<NodeT> *Node = WorkStack.back().first; | |||
756 | const auto ChildIt = WorkStack.back().second; | |||
757 | ||||
758 | // If we visited all of the children of this node, "recurse" back up the | |||
759 | // stack setting the DFOutNum. | |||
760 | if (ChildIt == Node->end()) { | |||
761 | Node->DFSNumOut = DFSNum++; | |||
762 | WorkStack.pop_back(); | |||
763 | } else { | |||
764 | // Otherwise, recursively visit this child. | |||
765 | const DomTreeNodeBase<NodeT> *Child = *ChildIt; | |||
766 | ++WorkStack.back().second; | |||
767 | ||||
768 | WorkStack.push_back({Child, Child->begin()}); | |||
769 | Child->DFSNumIn = DFSNum++; | |||
770 | } | |||
771 | } | |||
772 | ||||
773 | SlowQueries = 0; | |||
774 | DFSInfoValid = true; | |||
775 | } | |||
776 | ||||
777 | /// recalculate - compute a dominator tree for the given function | |||
778 | void recalculate(ParentType &Func) { | |||
779 | Parent = &Func; | |||
780 | DomTreeBuilder::Calculate(*this); | |||
781 | } | |||
782 | ||||
783 | void recalculate(ParentType &Func, ArrayRef<UpdateType> Updates) { | |||
784 | Parent = &Func; | |||
785 | DomTreeBuilder::CalculateWithUpdates(*this, Updates); | |||
786 | } | |||
787 | ||||
788 | /// verify - checks if the tree is correct. There are 3 level of verification: | |||
789 | /// - Full -- verifies if the tree is correct by making sure all the | |||
790 | /// properties (including the parent and the sibling property) | |||
791 | /// hold. | |||
792 | /// Takes O(N^3) time. | |||
793 | /// | |||
794 | /// - Basic -- checks if the tree is correct, but compares it to a freshly | |||
795 | /// constructed tree instead of checking the sibling property. | |||
796 | /// Takes O(N^2) time. | |||
797 | /// | |||
798 | /// - Fast -- checks basic tree structure and compares it with a freshly | |||
799 | /// constructed tree. | |||
800 | /// Takes O(N^2) time worst case, but is faster in practise (same | |||
801 | /// as tree construction). | |||
802 | bool verify(VerificationLevel VL = VerificationLevel::Full) const { | |||
803 | return DomTreeBuilder::Verify(*this, VL); | |||
804 | } | |||
805 | ||||
806 | void reset() { | |||
807 | DomTreeNodes.clear(); | |||
808 | Roots.clear(); | |||
809 | RootNode = nullptr; | |||
810 | Parent = nullptr; | |||
811 | DFSInfoValid = false; | |||
812 | SlowQueries = 0; | |||
813 | } | |||
814 | ||||
815 | protected: | |||
816 | void addRoot(NodeT *BB) { this->Roots.push_back(BB); } | |||
817 | ||||
818 | DomTreeNodeBase<NodeT> *createChild(NodeT *BB, DomTreeNodeBase<NodeT> *IDom) { | |||
819 | return (DomTreeNodes[BB] = IDom->addChild( | |||
820 | std::make_unique<DomTreeNodeBase<NodeT>>(BB, IDom))) | |||
821 | .get(); | |||
822 | } | |||
823 | ||||
824 | DomTreeNodeBase<NodeT> *createNode(NodeT *BB) { | |||
825 | return (DomTreeNodes[BB] = | |||
826 | std::make_unique<DomTreeNodeBase<NodeT>>(BB, nullptr)) | |||
827 | .get(); | |||
828 | } | |||
829 | ||||
830 | // NewBB is split and now it has one successor. Update dominator tree to | |||
831 | // reflect this change. | |||
832 | template <class N> | |||
833 | void Split(typename GraphTraits<N>::NodeRef NewBB) { | |||
834 | using GraphT = GraphTraits<N>; | |||
835 | using NodeRef = typename GraphT::NodeRef; | |||
836 | assert(std::distance(GraphT::child_begin(NewBB),((void)0) | |||
837 | GraphT::child_end(NewBB)) == 1 &&((void)0) | |||
838 | "NewBB should have a single successor!")((void)0); | |||
839 | NodeRef NewBBSucc = *GraphT::child_begin(NewBB); | |||
840 | ||||
841 | SmallVector<NodeRef, 4> PredBlocks(children<Inverse<N>>(NewBB)); | |||
842 | ||||
843 | assert(!PredBlocks.empty() && "No predblocks?")((void)0); | |||
844 | ||||
845 | bool NewBBDominatesNewBBSucc = true; | |||
846 | for (auto Pred : children<Inverse<N>>(NewBBSucc)) { | |||
847 | if (Pred != NewBB && !dominates(NewBBSucc, Pred) && | |||
848 | isReachableFromEntry(Pred)) { | |||
849 | NewBBDominatesNewBBSucc = false; | |||
850 | break; | |||
851 | } | |||
852 | } | |||
853 | ||||
854 | // Find NewBB's immediate dominator and create new dominator tree node for | |||
855 | // NewBB. | |||
856 | NodeT *NewBBIDom = nullptr; | |||
857 | unsigned i = 0; | |||
858 | for (i = 0; i < PredBlocks.size(); ++i) | |||
859 | if (isReachableFromEntry(PredBlocks[i])) { | |||
860 | NewBBIDom = PredBlocks[i]; | |||
861 | break; | |||
862 | } | |||
863 | ||||
864 | // It's possible that none of the predecessors of NewBB are reachable; | |||
865 | // in that case, NewBB itself is unreachable, so nothing needs to be | |||
866 | // changed. | |||
867 | if (!NewBBIDom) return; | |||
868 | ||||
869 | for (i = i + 1; i < PredBlocks.size(); ++i) { | |||
870 | if (isReachableFromEntry(PredBlocks[i])) | |||
871 | NewBBIDom = findNearestCommonDominator(NewBBIDom, PredBlocks[i]); | |||
872 | } | |||
873 | ||||
874 | // Create the new dominator tree node... and set the idom of NewBB. | |||
875 | DomTreeNodeBase<NodeT> *NewBBNode = addNewBlock(NewBB, NewBBIDom); | |||
876 | ||||
877 | // If NewBB strictly dominates other blocks, then it is now the immediate | |||
878 | // dominator of NewBBSucc. Update the dominator tree as appropriate. | |||
879 | if (NewBBDominatesNewBBSucc) { | |||
880 | DomTreeNodeBase<NodeT> *NewBBSuccNode = getNode(NewBBSucc); | |||
881 | changeImmediateDominator(NewBBSuccNode, NewBBNode); | |||
882 | } | |||
883 | } | |||
884 | ||||
885 | private: | |||
886 | bool dominatedBySlowTreeWalk(const DomTreeNodeBase<NodeT> *A, | |||
887 | const DomTreeNodeBase<NodeT> *B) const { | |||
888 | assert(A != B)((void)0); | |||
889 | assert(isReachableFromEntry(B))((void)0); | |||
890 | assert(isReachableFromEntry(A))((void)0); | |||
891 | ||||
892 | const unsigned ALevel = A->getLevel(); | |||
893 | const DomTreeNodeBase<NodeT> *IDom; | |||
894 | ||||
895 | // Don't walk nodes above A's subtree. When we reach A's level, we must | |||
896 | // either find A or be in some other subtree not dominated by A. | |||
897 | while ((IDom = B->getIDom()) != nullptr && IDom->getLevel() >= ALevel) | |||
898 | B = IDom; // Walk up the tree | |||
899 | ||||
900 | return B == A; | |||
901 | } | |||
902 | ||||
903 | /// Wipe this tree's state without releasing any resources. | |||
904 | /// | |||
905 | /// This is essentially a post-move helper only. It leaves the object in an | |||
906 | /// assignable and destroyable state, but otherwise invalid. | |||
907 | void wipe() { | |||
908 | DomTreeNodes.clear(); | |||
909 | RootNode = nullptr; | |||
910 | Parent = nullptr; | |||
911 | } | |||
912 | }; | |||
913 | ||||
914 | template <typename T> | |||
915 | using DomTreeBase = DominatorTreeBase<T, false>; | |||
916 | ||||
917 | template <typename T> | |||
918 | using PostDomTreeBase = DominatorTreeBase<T, true>; | |||
919 | ||||
920 | // These two functions are declared out of line as a workaround for building | |||
921 | // with old (< r147295) versions of clang because of pr11642. | |||
922 | template <typename NodeT, bool IsPostDom> | |||
923 | bool DominatorTreeBase<NodeT, IsPostDom>::dominates(const NodeT *A, | |||
924 | const NodeT *B) const { | |||
925 | if (A == B) | |||
926 | return true; | |||
927 | ||||
928 | // Cast away the const qualifiers here. This is ok since | |||
929 | // this function doesn't actually return the values returned | |||
930 | // from getNode. | |||
931 | return dominates(getNode(const_cast<NodeT *>(A)), | |||
932 | getNode(const_cast<NodeT *>(B))); | |||
933 | } | |||
934 | template <typename NodeT, bool IsPostDom> | |||
935 | bool DominatorTreeBase<NodeT, IsPostDom>::properlyDominates( | |||
936 | const NodeT *A, const NodeT *B) const { | |||
937 | if (A == B) | |||
938 | return false; | |||
939 | ||||
940 | // Cast away the const qualifiers here. This is ok since | |||
941 | // this function doesn't actually return the values returned | |||
942 | // from getNode. | |||
943 | return dominates(getNode(const_cast<NodeT *>(A)), | |||
944 | getNode(const_cast<NodeT *>(B))); | |||
945 | } | |||
946 | ||||
947 | } // end namespace llvm | |||
948 | ||||
949 | #endif // LLVM_SUPPORT_GENERICDOMTREE_H |
1 | //===- llvm/ADT/DenseMap.h - Dense probed hash table ------------*- C++ -*-===// |
2 | // |
3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
4 | // See https://llvm.org/LICENSE.txt for license information. |
5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
6 | // |
7 | //===----------------------------------------------------------------------===// |
8 | // |
9 | // This file defines the DenseMap class. |
10 | // |
11 | //===----------------------------------------------------------------------===// |
12 | |
13 | #ifndef LLVM_ADT_DENSEMAP_H |
14 | #define LLVM_ADT_DENSEMAP_H |
15 | |
16 | #include "llvm/ADT/DenseMapInfo.h" |
17 | #include "llvm/ADT/EpochTracker.h" |
18 | #include "llvm/Support/AlignOf.h" |
19 | #include "llvm/Support/Compiler.h" |
20 | #include "llvm/Support/MathExtras.h" |
21 | #include "llvm/Support/MemAlloc.h" |
22 | #include "llvm/Support/ReverseIteration.h" |
23 | #include "llvm/Support/type_traits.h" |
24 | #include <algorithm> |
25 | #include <cassert> |
26 | #include <cstddef> |
27 | #include <cstring> |
28 | #include <initializer_list> |
29 | #include <iterator> |
30 | #include <new> |
31 | #include <type_traits> |
32 | #include <utility> |
33 | |
34 | namespace llvm { |
35 | |
36 | namespace detail { |
37 | |
38 | // We extend a pair to allow users to override the bucket type with their own |
39 | // implementation without requiring two members. |
40 | template <typename KeyT, typename ValueT> |
41 | struct DenseMapPair : public std::pair<KeyT, ValueT> { |
42 | using std::pair<KeyT, ValueT>::pair; |
43 | |
44 | KeyT &getFirst() { return std::pair<KeyT, ValueT>::first; } |
45 | const KeyT &getFirst() const { return std::pair<KeyT, ValueT>::first; } |
46 | ValueT &getSecond() { return std::pair<KeyT, ValueT>::second; } |
47 | const ValueT &getSecond() const { return std::pair<KeyT, ValueT>::second; } |
48 | }; |
49 | |
50 | } // end namespace detail |
51 | |
52 | template <typename KeyT, typename ValueT, |
53 | typename KeyInfoT = DenseMapInfo<KeyT>, |
54 | typename Bucket = llvm::detail::DenseMapPair<KeyT, ValueT>, |
55 | bool IsConst = false> |
56 | class DenseMapIterator; |
57 | |
58 | template <typename DerivedT, typename KeyT, typename ValueT, typename KeyInfoT, |
59 | typename BucketT> |
60 | class DenseMapBase : public DebugEpochBase { |
61 | template <typename T> |
62 | using const_arg_type_t = typename const_pointer_or_const_ref<T>::type; |
63 | |
64 | public: |
65 | using size_type = unsigned; |
66 | using key_type = KeyT; |
67 | using mapped_type = ValueT; |
68 | using value_type = BucketT; |
69 | |
70 | using iterator = DenseMapIterator<KeyT, ValueT, KeyInfoT, BucketT>; |
71 | using const_iterator = |
72 | DenseMapIterator<KeyT, ValueT, KeyInfoT, BucketT, true>; |
73 | |
74 | inline iterator begin() { |
75 | // When the map is empty, avoid the overhead of advancing/retreating past |
76 | // empty buckets. |
77 | if (empty()) |
78 | return end(); |
79 | if (shouldReverseIterate<KeyT>()) |
80 | return makeIterator(getBucketsEnd() - 1, getBuckets(), *this); |
81 | return makeIterator(getBuckets(), getBucketsEnd(), *this); |
82 | } |
83 | inline iterator end() { |
84 | return makeIterator(getBucketsEnd(), getBucketsEnd(), *this, true); |
85 | } |
86 | inline const_iterator begin() const { |
87 | if (empty()) |
88 | return end(); |
89 | if (shouldReverseIterate<KeyT>()) |
90 | return makeConstIterator(getBucketsEnd() - 1, getBuckets(), *this); |
91 | return makeConstIterator(getBuckets(), getBucketsEnd(), *this); |
92 | } |
93 | inline const_iterator end() const { |
94 | return makeConstIterator(getBucketsEnd(), getBucketsEnd(), *this, true); |
95 | } |
96 | |
97 | LLVM_NODISCARD[[clang::warn_unused_result]] bool empty() const { |
98 | return getNumEntries() == 0; |
99 | } |
100 | unsigned size() const { return getNumEntries(); } |
101 | |
102 | /// Grow the densemap so that it can contain at least \p NumEntries items |
103 | /// before resizing again. |
104 | void reserve(size_type NumEntries) { |
105 | auto NumBuckets = getMinBucketToReserveForEntries(NumEntries); |
106 | incrementEpoch(); |
107 | if (NumBuckets > getNumBuckets()) |
108 | grow(NumBuckets); |
109 | } |
110 | |
111 | void clear() { |
112 | incrementEpoch(); |
113 | if (getNumEntries() == 0 && getNumTombstones() == 0) return; |
114 | |
115 | // If the capacity of the array is huge, and the # elements used is small, |
116 | // shrink the array. |
117 | if (getNumEntries() * 4 < getNumBuckets() && getNumBuckets() > 64) { |
118 | shrink_and_clear(); |
119 | return; |
120 | } |
121 | |
122 | const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey(); |
123 | if (std::is_trivially_destructible<ValueT>::value) { |
124 | // Use a simpler loop when values don't need destruction. |
125 | for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) |
126 | P->getFirst() = EmptyKey; |
127 | } else { |
128 | unsigned NumEntries = getNumEntries(); |
129 | for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) { |
130 | if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey)) { |
131 | if (!KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) { |
132 | P->getSecond().~ValueT(); |
133 | --NumEntries; |
134 | } |
135 | P->getFirst() = EmptyKey; |
136 | } |
137 | } |
138 | assert(NumEntries == 0 && "Node count imbalance!")((void)0); |
139 | } |
140 | setNumEntries(0); |
141 | setNumTombstones(0); |
142 | } |
143 | |
144 | /// Return 1 if the specified key is in the map, 0 otherwise. |
145 | size_type count(const_arg_type_t<KeyT> Val) const { |
146 | const BucketT *TheBucket; |
147 | return LookupBucketFor(Val, TheBucket) ? 1 : 0; |
148 | } |
149 | |
150 | iterator find(const_arg_type_t<KeyT> Val) { |
151 | BucketT *TheBucket; |
152 | if (LookupBucketFor(Val, TheBucket)) |
153 | return makeIterator(TheBucket, |
154 | shouldReverseIterate<KeyT>() ? getBuckets() |
155 | : getBucketsEnd(), |
156 | *this, true); |
157 | return end(); |
158 | } |
159 | const_iterator find(const_arg_type_t<KeyT> Val) const { |
160 | const BucketT *TheBucket; |
161 | if (LookupBucketFor(Val, TheBucket)) |
162 | return makeConstIterator(TheBucket, |
163 | shouldReverseIterate<KeyT>() ? getBuckets() |
164 | : getBucketsEnd(), |
165 | *this, true); |
166 | return end(); |
167 | } |
168 | |
169 | /// Alternate version of find() which allows a different, and possibly |
170 | /// less expensive, key type. |
171 | /// The DenseMapInfo is responsible for supplying methods |
172 | /// getHashValue(LookupKeyT) and isEqual(LookupKeyT, KeyT) for each key |
173 | /// type used. |
174 | template<class LookupKeyT> |
175 | iterator find_as(const LookupKeyT &Val) { |
176 | BucketT *TheBucket; |
177 | if (LookupBucketFor(Val, TheBucket)) |
178 | return makeIterator(TheBucket, |
179 | shouldReverseIterate<KeyT>() ? getBuckets() |
180 | : getBucketsEnd(), |
181 | *this, true); |
182 | return end(); |
183 | } |
184 | template<class LookupKeyT> |
185 | const_iterator find_as(const LookupKeyT &Val) const { |
186 | const BucketT *TheBucket; |
187 | if (LookupBucketFor(Val, TheBucket)) |
188 | return makeConstIterator(TheBucket, |
189 | shouldReverseIterate<KeyT>() ? getBuckets() |
190 | : getBucketsEnd(), |
191 | *this, true); |
192 | return end(); |
193 | } |
194 | |
195 | /// lookup - Return the entry for the specified key, or a default |
196 | /// constructed value if no such entry exists. |
197 | ValueT lookup(const_arg_type_t<KeyT> Val) const { |
198 | const BucketT *TheBucket; |
199 | if (LookupBucketFor(Val, TheBucket)) |
200 | return TheBucket->getSecond(); |
201 | return ValueT(); |
202 | } |
203 | |
204 | // Inserts key,value pair into the map if the key isn't already in the map. |
205 | // If the key is already in the map, it returns false and doesn't update the |
206 | // value. |
207 | std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &KV) { |
208 | return try_emplace(KV.first, KV.second); |
209 | } |
210 | |
211 | // Inserts key,value pair into the map if the key isn't already in the map. |
212 | // If the key is already in the map, it returns false and doesn't update the |
213 | // value. |
214 | std::pair<iterator, bool> insert(std::pair<KeyT, ValueT> &&KV) { |
215 | return try_emplace(std::move(KV.first), std::move(KV.second)); |
216 | } |
217 | |
218 | // Inserts key,value pair into the map if the key isn't already in the map. |
219 | // The value is constructed in-place if the key is not in the map, otherwise |
220 | // it is not moved. |
221 | template <typename... Ts> |
222 | std::pair<iterator, bool> try_emplace(KeyT &&Key, Ts &&... Args) { |
223 | BucketT *TheBucket; |
224 | if (LookupBucketFor(Key, TheBucket)) |
225 | return std::make_pair(makeIterator(TheBucket, |
226 | shouldReverseIterate<KeyT>() |
227 | ? getBuckets() |
228 | : getBucketsEnd(), |
229 | *this, true), |
230 | false); // Already in map. |
231 | |
232 | // Otherwise, insert the new element. |
233 | TheBucket = |
234 | InsertIntoBucket(TheBucket, std::move(Key), std::forward<Ts>(Args)...); |
235 | return std::make_pair(makeIterator(TheBucket, |
236 | shouldReverseIterate<KeyT>() |
237 | ? getBuckets() |
238 | : getBucketsEnd(), |
239 | *this, true), |
240 | true); |
241 | } |
242 | |
243 | // Inserts key,value pair into the map if the key isn't already in the map. |
244 | // The value is constructed in-place if the key is not in the map, otherwise |
245 | // it is not moved. |
246 | template <typename... Ts> |
247 | std::pair<iterator, bool> try_emplace(const KeyT &Key, Ts &&... Args) { |
248 | BucketT *TheBucket; |
249 | if (LookupBucketFor(Key, TheBucket)) |
250 | return std::make_pair(makeIterator(TheBucket, |
251 | shouldReverseIterate<KeyT>() |
252 | ? getBuckets() |
253 | : getBucketsEnd(), |
254 | *this, true), |
255 | false); // Already in map. |
256 | |
257 | // Otherwise, insert the new element. |
258 | TheBucket = InsertIntoBucket(TheBucket, Key, std::forward<Ts>(Args)...); |
259 | return std::make_pair(makeIterator(TheBucket, |
260 | shouldReverseIterate<KeyT>() |
261 | ? getBuckets() |
262 | : getBucketsEnd(), |
263 | *this, true), |
264 | true); |
265 | } |
266 | |
267 | /// Alternate version of insert() which allows a different, and possibly |
268 | /// less expensive, key type. |
269 | /// The DenseMapInfo is responsible for supplying methods |
270 | /// getHashValue(LookupKeyT) and isEqual(LookupKeyT, KeyT) for each key |
271 | /// type used. |
272 | template <typename LookupKeyT> |
273 | std::pair<iterator, bool> insert_as(std::pair<KeyT, ValueT> &&KV, |
274 | const LookupKeyT &Val) { |
275 | BucketT *TheBucket; |
276 | if (LookupBucketFor(Val, TheBucket)) |
277 | return std::make_pair(makeIterator(TheBucket, |
278 | shouldReverseIterate<KeyT>() |
279 | ? getBuckets() |
280 | : getBucketsEnd(), |
281 | *this, true), |
282 | false); // Already in map. |
283 | |
284 | // Otherwise, insert the new element. |
285 | TheBucket = InsertIntoBucketWithLookup(TheBucket, std::move(KV.first), |
286 | std::move(KV.second), Val); |
287 | return std::make_pair(makeIterator(TheBucket, |
288 | shouldReverseIterate<KeyT>() |
289 | ? getBuckets() |
290 | : getBucketsEnd(), |
291 | *this, true), |
292 | true); |
293 | } |
294 | |
295 | /// insert - Range insertion of pairs. |
296 | template<typename InputIt> |
297 | void insert(InputIt I, InputIt E) { |
298 | for (; I != E; ++I) |
299 | insert(*I); |
300 | } |
301 | |
302 | bool erase(const KeyT &Val) { |
303 | BucketT *TheBucket; |
304 | if (!LookupBucketFor(Val, TheBucket)) |
305 | return false; // not in map. |
306 | |
307 | TheBucket->getSecond().~ValueT(); |
308 | TheBucket->getFirst() = getTombstoneKey(); |
309 | decrementNumEntries(); |
310 | incrementNumTombstones(); |
311 | return true; |
312 | } |
313 | void erase(iterator I) { |
314 | BucketT *TheBucket = &*I; |
315 | TheBucket->getSecond().~ValueT(); |
316 | TheBucket->getFirst() = getTombstoneKey(); |
317 | decrementNumEntries(); |
318 | incrementNumTombstones(); |
319 | } |
320 | |
321 | value_type& FindAndConstruct(const KeyT &Key) { |
322 | BucketT *TheBucket; |
323 | if (LookupBucketFor(Key, TheBucket)) |
324 | return *TheBucket; |
325 | |
326 | return *InsertIntoBucket(TheBucket, Key); |
327 | } |
328 | |
329 | ValueT &operator[](const KeyT &Key) { |
330 | return FindAndConstruct(Key).second; |
331 | } |
332 | |
333 | value_type& FindAndConstruct(KeyT &&Key) { |
334 | BucketT *TheBucket; |
335 | if (LookupBucketFor(Key, TheBucket)) |
336 | return *TheBucket; |
337 | |
338 | return *InsertIntoBucket(TheBucket, std::move(Key)); |
339 | } |
340 | |
341 | ValueT &operator[](KeyT &&Key) { |
342 | return FindAndConstruct(std::move(Key)).second; |
343 | } |
344 | |
345 | /// isPointerIntoBucketsArray - Return true if the specified pointer points |
346 | /// somewhere into the DenseMap's array of buckets (i.e. either to a key or |
347 | /// value in the DenseMap). |
348 | bool isPointerIntoBucketsArray(const void *Ptr) const { |
349 | return Ptr >= getBuckets() && Ptr < getBucketsEnd(); |
350 | } |
351 | |
352 | /// getPointerIntoBucketsArray() - Return an opaque pointer into the buckets |
353 | /// array. In conjunction with the previous method, this can be used to |
354 | /// determine whether an insertion caused the DenseMap to reallocate. |
355 | const void *getPointerIntoBucketsArray() const { return getBuckets(); } |
356 | |
357 | protected: |
358 | DenseMapBase() = default; |
359 | |
360 | void destroyAll() { |
361 | if (getNumBuckets() == 0) // Nothing to do. |
362 | return; |
363 | |
364 | const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey(); |
365 | for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) { |
366 | if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey) && |
367 | !KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) |
368 | P->getSecond().~ValueT(); |
369 | P->getFirst().~KeyT(); |
370 | } |
371 | } |
372 | |
373 | void initEmpty() { |
374 | setNumEntries(0); |
375 | setNumTombstones(0); |
376 | |
377 | assert((getNumBuckets() & (getNumBuckets()-1)) == 0 &&((void)0) |
378 | "# initial buckets must be a power of two!")((void)0); |
379 | const KeyT EmptyKey = getEmptyKey(); |
380 | for (BucketT *B = getBuckets(), *E = getBucketsEnd(); B != E; ++B) |
381 | ::new (&B->getFirst()) KeyT(EmptyKey); |
382 | } |
383 | |
384 | /// Returns the number of buckets to allocate to ensure that the DenseMap can |
385 | /// accommodate \p NumEntries without need to grow(). |
386 | unsigned getMinBucketToReserveForEntries(unsigned NumEntries) { |
387 | // Ensure that "NumEntries * 4 < NumBuckets * 3" |
388 | if (NumEntries == 0) |
389 | return 0; |
390 | // +1 is required because of the strict equality. |
391 | // For example if NumEntries is 48, we need to return 401. |
392 | return NextPowerOf2(NumEntries * 4 / 3 + 1); |
393 | } |
394 | |
395 | void moveFromOldBuckets(BucketT *OldBucketsBegin, BucketT *OldBucketsEnd) { |
396 | initEmpty(); |
397 | |
398 | // Insert all the old elements. |
399 | const KeyT EmptyKey = getEmptyKey(); |
400 | const KeyT TombstoneKey = getTombstoneKey(); |
401 | for (BucketT *B = OldBucketsBegin, *E = OldBucketsEnd; B != E; ++B) { |
402 | if (!KeyInfoT::isEqual(B->getFirst(), EmptyKey) && |
403 | !KeyInfoT::isEqual(B->getFirst(), TombstoneKey)) { |
404 | // Insert the key/value into the new table. |
405 | BucketT *DestBucket; |
406 | bool FoundVal = LookupBucketFor(B->getFirst(), DestBucket); |
407 | (void)FoundVal; // silence warning. |
408 | assert(!FoundVal && "Key already in new map?")((void)0); |
409 | DestBucket->getFirst() = std::move(B->getFirst()); |
410 | ::new (&DestBucket->getSecond()) ValueT(std::move(B->getSecond())); |
411 | incrementNumEntries(); |
412 | |
413 | // Free the value. |
414 | B->getSecond().~ValueT(); |
415 | } |
416 | B->getFirst().~KeyT(); |
417 | } |
418 | } |
419 | |
420 | template <typename OtherBaseT> |
421 | void copyFrom( |
422 | const DenseMapBase<OtherBaseT, KeyT, ValueT, KeyInfoT, BucketT> &other) { |
423 | assert(&other != this)((void)0); |
424 | assert(getNumBuckets() == other.getNumBuckets())((void)0); |
425 | |
426 | setNumEntries(other.getNumEntries()); |
427 | setNumTombstones(other.getNumTombstones()); |
428 | |
429 | if (std::is_trivially_copyable<KeyT>::value && |
430 | std::is_trivially_copyable<ValueT>::value) |
431 | memcpy(reinterpret_cast<void *>(getBuckets()), other.getBuckets(), |
432 | getNumBuckets() * sizeof(BucketT)); |
433 | else |
434 | for (size_t i = 0; i < getNumBuckets(); ++i) { |
435 | ::new (&getBuckets()[i].getFirst()) |
436 | KeyT(other.getBuckets()[i].getFirst()); |
437 | if (!KeyInfoT::isEqual(getBuckets()[i].getFirst(), getEmptyKey()) && |
438 | !KeyInfoT::isEqual(getBuckets()[i].getFirst(), getTombstoneKey())) |
439 | ::new (&getBuckets()[i].getSecond()) |
440 | ValueT(other.getBuckets()[i].getSecond()); |
441 | } |
442 | } |
443 | |
444 | static unsigned getHashValue(const KeyT &Val) { |
445 | return KeyInfoT::getHashValue(Val); |
446 | } |
447 | |
448 | template<typename LookupKeyT> |
449 | static unsigned getHashValue(const LookupKeyT &Val) { |
450 | return KeyInfoT::getHashValue(Val); |
451 | } |
452 | |
453 | static const KeyT getEmptyKey() { |
454 | static_assert(std::is_base_of<DenseMapBase, DerivedT>::value, |
455 | "Must pass the derived type to this template!"); |
456 | return KeyInfoT::getEmptyKey(); |
457 | } |
458 | |
459 | static const KeyT getTombstoneKey() { |
460 | return KeyInfoT::getTombstoneKey(); |
461 | } |
462 | |
463 | private: |
464 | iterator makeIterator(BucketT *P, BucketT *E, |
465 | DebugEpochBase &Epoch, |
466 | bool NoAdvance=false) { |
467 | if (shouldReverseIterate<KeyT>()) { |
468 | BucketT *B = P == getBucketsEnd() ? getBuckets() : P + 1; |
469 | return iterator(B, E, Epoch, NoAdvance); |
470 | } |
471 | return iterator(P, E, Epoch, NoAdvance); |
472 | } |
473 | |
474 | const_iterator makeConstIterator(const BucketT *P, const BucketT *E, |
475 | const DebugEpochBase &Epoch, |
476 | const bool NoAdvance=false) const { |
477 | if (shouldReverseIterate<KeyT>()) { |
478 | const BucketT *B = P == getBucketsEnd() ? getBuckets() : P + 1; |
479 | return const_iterator(B, E, Epoch, NoAdvance); |
480 | } |
481 | return const_iterator(P, E, Epoch, NoAdvance); |
482 | } |
483 | |
484 | unsigned getNumEntries() const { |
485 | return static_cast<const DerivedT *>(this)->getNumEntries(); |
486 | } |
487 | |
488 | void setNumEntries(unsigned Num) { |
489 | static_cast<DerivedT *>(this)->setNumEntries(Num); |
490 | } |
491 | |
492 | void incrementNumEntries() { |
493 | setNumEntries(getNumEntries() + 1); |
494 | } |
495 | |
496 | void decrementNumEntries() { |
497 | setNumEntries(getNumEntries() - 1); |
498 | } |
499 | |
500 | unsigned getNumTombstones() const { |
501 | return static_cast<const DerivedT *>(this)->getNumTombstones(); |
502 | } |
503 | |
504 | void setNumTombstones(unsigned Num) { |
505 | static_cast<DerivedT *>(this)->setNumTombstones(Num); |
506 | } |
507 | |
508 | void incrementNumTombstones() { |
509 | setNumTombstones(getNumTombstones() + 1); |
510 | } |
511 | |
512 | void decrementNumTombstones() { |
513 | setNumTombstones(getNumTombstones() - 1); |
514 | } |
515 | |
516 | const BucketT *getBuckets() const { |
517 | return static_cast<const DerivedT *>(this)->getBuckets(); |
518 | } |
519 | |
520 | BucketT *getBuckets() { |
521 | return static_cast<DerivedT *>(this)->getBuckets(); |
522 | } |
523 | |
524 | unsigned getNumBuckets() const { |
525 | return static_cast<const DerivedT *>(this)->getNumBuckets(); |
526 | } |
527 | |
528 | BucketT *getBucketsEnd() { |
529 | return getBuckets() + getNumBuckets(); |
530 | } |
531 | |
532 | const BucketT *getBucketsEnd() const { |
533 | return getBuckets() + getNumBuckets(); |
534 | } |
535 | |
536 | void grow(unsigned AtLeast) { |
537 | static_cast<DerivedT *>(this)->grow(AtLeast); |
538 | } |
539 | |
540 | void shrink_and_clear() { |
541 | static_cast<DerivedT *>(this)->shrink_and_clear(); |
542 | } |
543 | |
544 | template <typename KeyArg, typename... ValueArgs> |
545 | BucketT *InsertIntoBucket(BucketT *TheBucket, KeyArg &&Key, |
546 | ValueArgs &&... Values) { |
547 | TheBucket = InsertIntoBucketImpl(Key, Key, TheBucket); |
548 | |
549 | TheBucket->getFirst() = std::forward<KeyArg>(Key); |
550 | ::new (&TheBucket->getSecond()) ValueT(std::forward<ValueArgs>(Values)...); |
551 | return TheBucket; |
552 | } |
553 | |
554 | template <typename LookupKeyT> |
555 | BucketT *InsertIntoBucketWithLookup(BucketT *TheBucket, KeyT &&Key, |
556 | ValueT &&Value, LookupKeyT &Lookup) { |
557 | TheBucket = InsertIntoBucketImpl(Key, Lookup, TheBucket); |
558 | |
559 | TheBucket->getFirst() = std::move(Key); |
560 | ::new (&TheBucket->getSecond()) ValueT(std::move(Value)); |
561 | return TheBucket; |
562 | } |
563 | |
564 | template <typename LookupKeyT> |
565 | BucketT *InsertIntoBucketImpl(const KeyT &Key, const LookupKeyT &Lookup, |
566 | BucketT *TheBucket) { |
567 | incrementEpoch(); |
568 | |
569 | // If the load of the hash table is more than 3/4, or if fewer than 1/8 of |
570 | // the buckets are empty (meaning that many are filled with tombstones), |
571 | // grow the table. |
572 | // |
573 | // The later case is tricky. For example, if we had one empty bucket with |
574 | // tons of tombstones, failing lookups (e.g. for insertion) would have to |
575 | // probe almost the entire table until it found the empty bucket. If the |
576 | // table completely filled with tombstones, no lookup would ever succeed, |
577 | // causing infinite loops in lookup. |
578 | unsigned NewNumEntries = getNumEntries() + 1; |
579 | unsigned NumBuckets = getNumBuckets(); |
580 | if (LLVM_UNLIKELY(NewNumEntries * 4 >= NumBuckets * 3)__builtin_expect((bool)(NewNumEntries * 4 >= NumBuckets * 3 ), false)) { |
581 | this->grow(NumBuckets * 2); |
582 | LookupBucketFor(Lookup, TheBucket); |
583 | NumBuckets = getNumBuckets(); |
584 | } else if (LLVM_UNLIKELY(NumBuckets-(NewNumEntries+getNumTombstones()) <=__builtin_expect((bool)(NumBuckets-(NewNumEntries+getNumTombstones ()) <= NumBuckets/8), false) |
585 | NumBuckets/8)__builtin_expect((bool)(NumBuckets-(NewNumEntries+getNumTombstones ()) <= NumBuckets/8), false)) { |
586 | this->grow(NumBuckets); |
587 | LookupBucketFor(Lookup, TheBucket); |
588 | } |
589 | assert(TheBucket)((void)0); |
590 | |
591 | // Only update the state after we've grown our bucket space appropriately |
592 | // so that when growing buckets we have self-consistent entry count. |
593 | incrementNumEntries(); |
594 | |
595 | // If we are writing over a tombstone, remember this. |
596 | const KeyT EmptyKey = getEmptyKey(); |
597 | if (!KeyInfoT::isEqual(TheBucket->getFirst(), EmptyKey)) |
598 | decrementNumTombstones(); |
599 | |
600 | return TheBucket; |
601 | } |
602 | |
603 | /// LookupBucketFor - Lookup the appropriate bucket for Val, returning it in |
604 | /// FoundBucket. If the bucket contains the key and a value, this returns |
605 | /// true, otherwise it returns a bucket with an empty marker or tombstone and |
606 | /// returns false. |
607 | template<typename LookupKeyT> |
608 | bool LookupBucketFor(const LookupKeyT &Val, |
609 | const BucketT *&FoundBucket) const { |
610 | const BucketT *BucketsPtr = getBuckets(); |
611 | const unsigned NumBuckets = getNumBuckets(); |
612 | |
613 | if (NumBuckets == 0) { |
614 | FoundBucket = nullptr; |
615 | return false; |
616 | } |
617 | |
618 | // FoundTombstone - Keep track of whether we find a tombstone while probing. |
619 | const BucketT *FoundTombstone = nullptr; |
620 | const KeyT EmptyKey = getEmptyKey(); |
621 | const KeyT TombstoneKey = getTombstoneKey(); |
622 | assert(!KeyInfoT::isEqual(Val, EmptyKey) &&((void)0) |
623 | !KeyInfoT::isEqual(Val, TombstoneKey) &&((void)0) |
624 | "Empty/Tombstone value shouldn't be inserted into map!")((void)0); |
625 | |
626 | unsigned BucketNo = getHashValue(Val) & (NumBuckets-1); |
627 | unsigned ProbeAmt = 1; |
628 | while (true) { |
629 | const BucketT *ThisBucket = BucketsPtr + BucketNo; |
630 | // Found Val's bucket? If so, return it. |
631 | if (LLVM_LIKELY(KeyInfoT::isEqual(Val, ThisBucket->getFirst()))__builtin_expect((bool)(KeyInfoT::isEqual(Val, ThisBucket-> getFirst())), true)) { |
632 | FoundBucket = ThisBucket; |
633 | return true; |
634 | } |
635 | |
636 | // If we found an empty bucket, the key doesn't exist in the set. |
637 | // Insert it and return the default value. |
638 | if (LLVM_LIKELY(KeyInfoT::isEqual(ThisBucket->getFirst(), EmptyKey))__builtin_expect((bool)(KeyInfoT::isEqual(ThisBucket->getFirst (), EmptyKey)), true)) { |
639 | // If we've already seen a tombstone while probing, fill it in instead |
640 | // of the empty bucket we eventually probed to. |
641 | FoundBucket = FoundTombstone ? FoundTombstone : ThisBucket; |
642 | return false; |
643 | } |
644 | |
645 | // If this is a tombstone, remember it. If Val ends up not in the map, we |
646 | // prefer to return it than something that would require more probing. |
647 | if (KeyInfoT::isEqual(ThisBucket->getFirst(), TombstoneKey) && |
648 | !FoundTombstone) |
649 | FoundTombstone = ThisBucket; // Remember the first tombstone found. |
650 | |
651 | // Otherwise, it's a hash collision or a tombstone, continue quadratic |
652 | // probing. |
653 | BucketNo += ProbeAmt++; |
654 | BucketNo &= (NumBuckets-1); |
655 | } |
656 | } |
657 | |
658 | template <typename LookupKeyT> |
659 | bool LookupBucketFor(const LookupKeyT &Val, BucketT *&FoundBucket) { |
660 | const BucketT *ConstFoundBucket; |
661 | bool Result = const_cast<const DenseMapBase *>(this) |
662 | ->LookupBucketFor(Val, ConstFoundBucket); |
663 | FoundBucket = const_cast<BucketT *>(ConstFoundBucket); |
664 | return Result; |
665 | } |
666 | |
667 | public: |
668 | /// Return the approximate size (in bytes) of the actual map. |
669 | /// This is just the raw memory used by DenseMap. |
670 | /// If entries are pointers to objects, the size of the referenced objects |
671 | /// are not included. |
672 | size_t getMemorySize() const { |
673 | return getNumBuckets() * sizeof(BucketT); |
674 | } |
675 | }; |
676 | |
677 | /// Equality comparison for DenseMap. |
678 | /// |
679 | /// Iterates over elements of LHS confirming that each (key, value) pair in LHS |
680 | /// is also in RHS, and that no additional pairs are in RHS. |
681 | /// Equivalent to N calls to RHS.find and N value comparisons. Amortized |
682 | /// complexity is linear, worst case is O(N^2) (if every hash collides). |
683 | template <typename DerivedT, typename KeyT, typename ValueT, typename KeyInfoT, |
684 | typename BucketT> |
685 | bool operator==( |
686 | const DenseMapBase<DerivedT, KeyT, ValueT, KeyInfoT, BucketT> &LHS, |
687 | const DenseMapBase<DerivedT, KeyT, ValueT, KeyInfoT, BucketT> &RHS) { |
688 | if (LHS.size() != RHS.size()) |
689 | return false; |
690 | |
691 | for (auto &KV : LHS) { |
692 | auto I = RHS.find(KV.first); |
693 | if (I == RHS.end() || I->second != KV.second) |
694 | return false; |
695 | } |
696 | |
697 | return true; |
698 | } |
699 | |
700 | /// Inequality comparison for DenseMap. |
701 | /// |
702 | /// Equivalent to !(LHS == RHS). See operator== for performance notes. |
703 | template <typename DerivedT, typename KeyT, typename ValueT, typename KeyInfoT, |
704 | typename BucketT> |
705 | bool operator!=( |
706 | const DenseMapBase<DerivedT, KeyT, ValueT, KeyInfoT, BucketT> &LHS, |
707 | const DenseMapBase<DerivedT, KeyT, ValueT, KeyInfoT, BucketT> &RHS) { |
708 | return !(LHS == RHS); |
709 | } |
710 | |
711 | template <typename KeyT, typename ValueT, |
712 | typename KeyInfoT = DenseMapInfo<KeyT>, |
713 | typename BucketT = llvm::detail::DenseMapPair<KeyT, ValueT>> |
714 | class DenseMap : public DenseMapBase<DenseMap<KeyT, ValueT, KeyInfoT, BucketT>, |
715 | KeyT, ValueT, KeyInfoT, BucketT> { |
716 | friend class DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT, BucketT>; |
717 | |
718 | // Lift some types from the dependent base class into this class for |
719 | // simplicity of referring to them. |
720 | using BaseT = DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT, BucketT>; |
721 | |
722 | BucketT *Buckets; |
723 | unsigned NumEntries; |
724 | unsigned NumTombstones; |
725 | unsigned NumBuckets; |
726 | |
727 | public: |
728 | /// Create a DenseMap with an optional \p InitialReserve that guarantee that |
729 | /// this number of elements can be inserted in the map without grow() |
730 | explicit DenseMap(unsigned InitialReserve = 0) { init(InitialReserve); } |
731 | |
732 | DenseMap(const DenseMap &other) : BaseT() { |
733 | init(0); |
734 | copyFrom(other); |
735 | } |
736 | |
737 | DenseMap(DenseMap &&other) : BaseT() { |
738 | init(0); |
739 | swap(other); |
740 | } |
741 | |
742 | template<typename InputIt> |
743 | DenseMap(const InputIt &I, const InputIt &E) { |
744 | init(std::distance(I, E)); |
745 | this->insert(I, E); |
746 | } |
747 | |
748 | DenseMap(std::initializer_list<typename BaseT::value_type> Vals) { |
749 | init(Vals.size()); |
750 | this->insert(Vals.begin(), Vals.end()); |
751 | } |
752 | |
753 | ~DenseMap() { |
754 | this->destroyAll(); |
755 | deallocate_buffer(Buckets, sizeof(BucketT) * NumBuckets, alignof(BucketT)); |
756 | } |
757 | |
758 | void swap(DenseMap& RHS) { |
759 | this->incrementEpoch(); |
760 | RHS.incrementEpoch(); |
761 | std::swap(Buckets, RHS.Buckets); |
762 | std::swap(NumEntries, RHS.NumEntries); |
763 | std::swap(NumTombstones, RHS.NumTombstones); |
764 | std::swap(NumBuckets, RHS.NumBuckets); |
765 | } |
766 | |
767 | DenseMap& operator=(const DenseMap& other) { |
768 | if (&other != this) |
769 | copyFrom(other); |
770 | return *this; |
771 | } |
772 | |
773 | DenseMap& operator=(DenseMap &&other) { |
774 | this->destroyAll(); |
775 | deallocate_buffer(Buckets, sizeof(BucketT) * NumBuckets, alignof(BucketT)); |
776 | init(0); |
777 | swap(other); |
778 | return *this; |
779 | } |
780 | |
781 | void copyFrom(const DenseMap& other) { |
782 | this->destroyAll(); |
783 | deallocate_buffer(Buckets, sizeof(BucketT) * NumBuckets, alignof(BucketT)); |
784 | if (allocateBuckets(other.NumBuckets)) { |
785 | this->BaseT::copyFrom(other); |
786 | } else { |
787 | NumEntries = 0; |
788 | NumTombstones = 0; |
789 | } |
790 | } |
791 | |
792 | void init(unsigned InitNumEntries) { |
793 | auto InitBuckets = BaseT::getMinBucketToReserveForEntries(InitNumEntries); |
794 | if (allocateBuckets(InitBuckets)) { |
795 | this->BaseT::initEmpty(); |
796 | } else { |
797 | NumEntries = 0; |
798 | NumTombstones = 0; |
799 | } |
800 | } |
801 | |
802 | void grow(unsigned AtLeast) { |
803 | unsigned OldNumBuckets = NumBuckets; |
804 | BucketT *OldBuckets = Buckets; |
805 | |
806 | allocateBuckets(std::max<unsigned>(64, static_cast<unsigned>(NextPowerOf2(AtLeast-1)))); |
807 | assert(Buckets)((void)0); |
808 | if (!OldBuckets) { |
809 | this->BaseT::initEmpty(); |
810 | return; |
811 | } |
812 | |
813 | this->moveFromOldBuckets(OldBuckets, OldBuckets+OldNumBuckets); |
814 | |
815 | // Free the old table. |
816 | deallocate_buffer(OldBuckets, sizeof(BucketT) * OldNumBuckets, |
817 | alignof(BucketT)); |
818 | } |
819 | |
820 | void shrink_and_clear() { |
821 | unsigned OldNumBuckets = NumBuckets; |
822 | unsigned OldNumEntries = NumEntries; |
823 | this->destroyAll(); |
824 | |
825 | // Reduce the number of buckets. |
826 | unsigned NewNumBuckets = 0; |
827 | if (OldNumEntries) |
828 | NewNumBuckets = std::max(64, 1 << (Log2_32_Ceil(OldNumEntries) + 1)); |
829 | if (NewNumBuckets == NumBuckets) { |
830 | this->BaseT::initEmpty(); |
831 | return; |
832 | } |
833 | |
834 | deallocate_buffer(Buckets, sizeof(BucketT) * OldNumBuckets, |
835 | alignof(BucketT)); |
836 | init(NewNumBuckets); |
837 | } |
838 | |
839 | private: |
840 | unsigned getNumEntries() const { |
841 | return NumEntries; |
842 | } |
843 | |
844 | void setNumEntries(unsigned Num) { |
845 | NumEntries = Num; |
846 | } |
847 | |
848 | unsigned getNumTombstones() const { |
849 | return NumTombstones; |
850 | } |
851 | |
852 | void setNumTombstones(unsigned Num) { |
853 | NumTombstones = Num; |
854 | } |
855 | |
856 | BucketT *getBuckets() const { |
857 | return Buckets; |
858 | } |
859 | |
860 | unsigned getNumBuckets() const { |
861 | return NumBuckets; |
862 | } |
863 | |
864 | bool allocateBuckets(unsigned Num) { |
865 | NumBuckets = Num; |
866 | if (NumBuckets == 0) { |
867 | Buckets = nullptr; |
868 | return false; |
869 | } |
870 | |
871 | Buckets = static_cast<BucketT *>( |
872 | allocate_buffer(sizeof(BucketT) * NumBuckets, alignof(BucketT))); |
873 | return true; |
874 | } |
875 | }; |
876 | |
877 | template <typename KeyT, typename ValueT, unsigned InlineBuckets = 4, |
878 | typename KeyInfoT = DenseMapInfo<KeyT>, |
879 | typename BucketT = llvm::detail::DenseMapPair<KeyT, ValueT>> |
880 | class SmallDenseMap |
881 | : public DenseMapBase< |
882 | SmallDenseMap<KeyT, ValueT, InlineBuckets, KeyInfoT, BucketT>, KeyT, |
883 | ValueT, KeyInfoT, BucketT> { |
884 | friend class DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT, BucketT>; |
885 | |
886 | // Lift some types from the dependent base class into this class for |
887 | // simplicity of referring to them. |
888 | using BaseT = DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT, BucketT>; |
889 | |
890 | static_assert(isPowerOf2_64(InlineBuckets), |
891 | "InlineBuckets must be a power of 2."); |
892 | |
893 | unsigned Small : 1; |
894 | unsigned NumEntries : 31; |
895 | unsigned NumTombstones; |
896 | |
897 | struct LargeRep { |
898 | BucketT *Buckets; |
899 | unsigned NumBuckets; |
900 | }; |
901 | |
902 | /// A "union" of an inline bucket array and the struct representing |
903 | /// a large bucket. This union will be discriminated by the 'Small' bit. |
904 | AlignedCharArrayUnion<BucketT[InlineBuckets], LargeRep> storage; |
905 | |
906 | public: |
907 | explicit SmallDenseMap(unsigned NumInitBuckets = 0) { |
908 | init(NumInitBuckets); |
909 | } |
910 | |
911 | SmallDenseMap(const SmallDenseMap &other) : BaseT() { |
912 | init(0); |
913 | copyFrom(other); |
914 | } |
915 | |
916 | SmallDenseMap(SmallDenseMap &&other) : BaseT() { |
917 | init(0); |
918 | swap(other); |
919 | } |
920 | |
921 | template<typename InputIt> |
922 | SmallDenseMap(const InputIt &I, const InputIt &E) { |
923 | init(NextPowerOf2(std::distance(I, E))); |
924 | this->insert(I, E); |
925 | } |
926 | |
927 | SmallDenseMap(std::initializer_list<typename BaseT::value_type> Vals) |
928 | : SmallDenseMap(Vals.begin(), Vals.end()) {} |
929 | |
930 | ~SmallDenseMap() { |
931 | this->destroyAll(); |
932 | deallocateBuckets(); |
933 | } |
934 | |
935 | void swap(SmallDenseMap& RHS) { |
936 | unsigned TmpNumEntries = RHS.NumEntries; |
937 | RHS.NumEntries = NumEntries; |
938 | NumEntries = TmpNumEntries; |
939 | std::swap(NumTombstones, RHS.NumTombstones); |
940 | |
941 | const KeyT EmptyKey = this->getEmptyKey(); |
942 | const KeyT TombstoneKey = this->getTombstoneKey(); |
943 | if (Small && RHS.Small) { |
944 | // If we're swapping inline bucket arrays, we have to cope with some of |
945 | // the tricky bits of DenseMap's storage system: the buckets are not |
946 | // fully initialized. Thus we swap every key, but we may have |
947 | // a one-directional move of the value. |
948 | for (unsigned i = 0, e = InlineBuckets; i != e; ++i) { |
949 | BucketT *LHSB = &getInlineBuckets()[i], |
950 | *RHSB = &RHS.getInlineBuckets()[i]; |
951 | bool hasLHSValue = (!KeyInfoT::isEqual(LHSB->getFirst(), EmptyKey) && |
952 | !KeyInfoT::isEqual(LHSB->getFirst(), TombstoneKey)); |
953 | bool hasRHSValue = (!KeyInfoT::isEqual(RHSB->getFirst(), EmptyKey) && |
954 | !KeyInfoT::isEqual(RHSB->getFirst(), TombstoneKey)); |
955 | if (hasLHSValue && hasRHSValue) { |
956 | // Swap together if we can... |
957 | std::swap(*LHSB, *RHSB); |
958 | continue; |
959 | } |
960 | // Swap separately and handle any asymmetry. |
961 | std::swap(LHSB->getFirst(), RHSB->getFirst()); |
962 | if (hasLHSValue) { |
963 | ::new (&RHSB->getSecond()) ValueT(std::move(LHSB->getSecond())); |
964 | LHSB->getSecond().~ValueT(); |
965 | } else if (hasRHSValue) { |
966 | ::new (&LHSB->getSecond()) ValueT(std::move(RHSB->getSecond())); |
967 | RHSB->getSecond().~ValueT(); |
968 | } |
969 | } |
970 | return; |
971 | } |
972 | if (!Small && !RHS.Small) { |
973 | std::swap(getLargeRep()->Buckets, RHS.getLargeRep()->Buckets); |
974 | std::swap(getLargeRep()->NumBuckets, RHS.getLargeRep()->NumBuckets); |
975 | return; |
976 | } |
977 | |
978 | SmallDenseMap &SmallSide = Small ? *this : RHS; |
979 | SmallDenseMap &LargeSide = Small ? RHS : *this; |
980 | |
981 | // First stash the large side's rep and move the small side across. |
982 | LargeRep TmpRep = std::move(*LargeSide.getLargeRep()); |
983 | LargeSide.getLargeRep()->~LargeRep(); |
984 | LargeSide.Small = true; |
985 | // This is similar to the standard move-from-old-buckets, but the bucket |
986 | // count hasn't actually rotated in this case. So we have to carefully |
987 | // move construct the keys and values into their new locations, but there |
988 | // is no need to re-hash things. |
989 | for (unsigned i = 0, e = InlineBuckets; i != e; ++i) { |
990 | BucketT *NewB = &LargeSide.getInlineBuckets()[i], |
991 | *OldB = &SmallSide.getInlineBuckets()[i]; |
992 | ::new (&NewB->getFirst()) KeyT(std::move(OldB->getFirst())); |
993 | OldB->getFirst().~KeyT(); |
994 | if (!KeyInfoT::isEqual(NewB->getFirst(), EmptyKey) && |
995 | !KeyInfoT::isEqual(NewB->getFirst(), TombstoneKey)) { |
996 | ::new (&NewB->getSecond()) ValueT(std::move(OldB->getSecond())); |
997 | OldB->getSecond().~ValueT(); |
998 | } |
999 | } |
1000 | |
1001 | // The hard part of moving the small buckets across is done, just move |
1002 | // the TmpRep into its new home. |
1003 | SmallSide.Small = false; |
1004 | new (SmallSide.getLargeRep()) LargeRep(std::move(TmpRep)); |
1005 | } |
1006 | |
1007 | SmallDenseMap& operator=(const SmallDenseMap& other) { |
1008 | if (&other != this) |
1009 | copyFrom(other); |
1010 | return *this; |
1011 | } |
1012 | |
1013 | SmallDenseMap& operator=(SmallDenseMap &&other) { |
1014 | this->destroyAll(); |
1015 | deallocateBuckets(); |
1016 | init(0); |
1017 | swap(other); |
1018 | return *this; |
1019 | } |
1020 | |
1021 | void copyFrom(const SmallDenseMap& other) { |
1022 | this->destroyAll(); |
1023 | deallocateBuckets(); |
1024 | Small = true; |
1025 | if (other.getNumBuckets() > InlineBuckets) { |
1026 | Small = false; |
1027 | new (getLargeRep()) LargeRep(allocateBuckets(other.getNumBuckets())); |
1028 | } |
1029 | this->BaseT::copyFrom(other); |
1030 | } |
1031 | |
1032 | void init(unsigned InitBuckets) { |
1033 | Small = true; |
1034 | if (InitBuckets > InlineBuckets) { |
1035 | Small = false; |
1036 | new (getLargeRep()) LargeRep(allocateBuckets(InitBuckets)); |
1037 | } |
1038 | this->BaseT::initEmpty(); |
1039 | } |
1040 | |
1041 | void grow(unsigned AtLeast) { |
1042 | if (AtLeast > InlineBuckets) |
1043 | AtLeast = std::max<unsigned>(64, NextPowerOf2(AtLeast-1)); |
1044 | |
1045 | if (Small) { |
1046 | // First move the inline buckets into a temporary storage. |
1047 | AlignedCharArrayUnion<BucketT[InlineBuckets]> TmpStorage; |
1048 | BucketT *TmpBegin = reinterpret_cast<BucketT *>(&TmpStorage); |
1049 | BucketT *TmpEnd = TmpBegin; |
1050 | |
1051 | // Loop over the buckets, moving non-empty, non-tombstones into the |
1052 | // temporary storage. Have the loop move the TmpEnd forward as it goes. |
1053 | const KeyT EmptyKey = this->getEmptyKey(); |
1054 | const KeyT TombstoneKey = this->getTombstoneKey(); |
1055 | for (BucketT *P = getBuckets(), *E = P + InlineBuckets; P != E; ++P) { |
1056 | if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey) && |
1057 | !KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) { |
1058 | assert(size_t(TmpEnd - TmpBegin) < InlineBuckets &&((void)0) |
1059 | "Too many inline buckets!")((void)0); |
1060 | ::new (&TmpEnd->getFirst()) KeyT(std::move(P->getFirst())); |
1061 | ::new (&TmpEnd->getSecond()) ValueT(std::move(P->getSecond())); |
1062 | ++TmpEnd; |
1063 | P->getSecond().~ValueT(); |
1064 | } |
1065 | P->getFirst().~KeyT(); |
1066 | } |
1067 | |
1068 | // AtLeast == InlineBuckets can happen if there are many tombstones, |
1069 | // and grow() is used to remove them. Usually we always switch to the |
1070 | // large rep here. |
1071 | if (AtLeast > InlineBuckets) { |
1072 | Small = false; |
1073 | new (getLargeRep()) LargeRep(allocateBuckets(AtLeast)); |
1074 | } |
1075 | this->moveFromOldBuckets(TmpBegin, TmpEnd); |
1076 | return; |
1077 | } |
1078 | |
1079 | LargeRep OldRep = std::move(*getLargeRep()); |
1080 | getLargeRep()->~LargeRep(); |
1081 | if (AtLeast <= InlineBuckets) { |
1082 | Small = true; |
1083 | } else { |
1084 | new (getLargeRep()) LargeRep(allocateBuckets(AtLeast)); |
1085 | } |
1086 | |
1087 | this->moveFromOldBuckets(OldRep.Buckets, OldRep.Buckets+OldRep.NumBuckets); |
1088 | |
1089 | // Free the old table. |
1090 | deallocate_buffer(OldRep.Buckets, sizeof(BucketT) * OldRep.NumBuckets, |
1091 | alignof(BucketT)); |
1092 | } |
1093 | |
1094 | void shrink_and_clear() { |
1095 | unsigned OldSize = this->size(); |
1096 | this->destroyAll(); |
1097 | |
1098 | // Reduce the number of buckets. |
1099 | unsigned NewNumBuckets = 0; |
1100 | if (OldSize) { |
1101 | NewNumBuckets = 1 << (Log2_32_Ceil(OldSize) + 1); |
1102 | if (NewNumBuckets > InlineBuckets && NewNumBuckets < 64u) |
1103 | NewNumBuckets = 64; |
1104 | } |
1105 | if ((Small && NewNumBuckets <= InlineBuckets) || |
1106 | (!Small && NewNumBuckets == getLargeRep()->NumBuckets)) { |
1107 | this->BaseT::initEmpty(); |
1108 | return; |
1109 | } |
1110 | |
1111 | deallocateBuckets(); |
1112 | init(NewNumBuckets); |
1113 | } |
1114 | |
1115 | private: |
1116 | unsigned getNumEntries() const { |
1117 | return NumEntries; |
1118 | } |
1119 | |
1120 | void setNumEntries(unsigned Num) { |
1121 | // NumEntries is hardcoded to be 31 bits wide. |
1122 | assert(Num < (1U << 31) && "Cannot support more than 1<<31 entries")((void)0); |
1123 | NumEntries = Num; |
1124 | } |
1125 | |
1126 | unsigned getNumTombstones() const { |
1127 | return NumTombstones; |
1128 | } |
1129 | |
1130 | void setNumTombstones(unsigned Num) { |
1131 | NumTombstones = Num; |
1132 | } |
1133 | |
1134 | const BucketT *getInlineBuckets() const { |
1135 | assert(Small)((void)0); |
1136 | // Note that this cast does not violate aliasing rules as we assert that |
1137 | // the memory's dynamic type is the small, inline bucket buffer, and the |
1138 | // 'storage' is a POD containing a char buffer. |
1139 | return reinterpret_cast<const BucketT *>(&storage); |
1140 | } |
1141 | |
1142 | BucketT *getInlineBuckets() { |
1143 | return const_cast<BucketT *>( |
1144 | const_cast<const SmallDenseMap *>(this)->getInlineBuckets()); |
1145 | } |
1146 | |
1147 | const LargeRep *getLargeRep() const { |
1148 | assert(!Small)((void)0); |
1149 | // Note, same rule about aliasing as with getInlineBuckets. |
1150 | return reinterpret_cast<const LargeRep *>(&storage); |
1151 | } |
1152 | |
1153 | LargeRep *getLargeRep() { |
1154 | return const_cast<LargeRep *>( |
1155 | const_cast<const SmallDenseMap *>(this)->getLargeRep()); |
1156 | } |
1157 | |
1158 | const BucketT *getBuckets() const { |
1159 | return Small ? getInlineBuckets() : getLargeRep()->Buckets; |
1160 | } |
1161 | |
1162 | BucketT *getBuckets() { |
1163 | return const_cast<BucketT *>( |
1164 | const_cast<const SmallDenseMap *>(this)->getBuckets()); |
1165 | } |
1166 | |
1167 | unsigned getNumBuckets() const { |
1168 | return Small ? InlineBuckets : getLargeRep()->NumBuckets; |
1169 | } |
1170 | |
1171 | void deallocateBuckets() { |
1172 | if (Small) |
1173 | return; |
1174 | |
1175 | deallocate_buffer(getLargeRep()->Buckets, |
1176 | sizeof(BucketT) * getLargeRep()->NumBuckets, |
1177 | alignof(BucketT)); |
1178 | getLargeRep()->~LargeRep(); |
1179 | } |
1180 | |
1181 | LargeRep allocateBuckets(unsigned Num) { |
1182 | assert(Num > InlineBuckets && "Must allocate more buckets than are inline")((void)0); |
1183 | LargeRep Rep = {static_cast<BucketT *>(allocate_buffer( |
1184 | sizeof(BucketT) * Num, alignof(BucketT))), |
1185 | Num}; |
1186 | return Rep; |
1187 | } |
1188 | }; |
1189 | |
1190 | template <typename KeyT, typename ValueT, typename KeyInfoT, typename Bucket, |
1191 | bool IsConst> |
1192 | class DenseMapIterator : DebugEpochBase::HandleBase { |
1193 | friend class DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, true>; |
1194 | friend class DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, false>; |
1195 | |
1196 | public: |
1197 | using difference_type = ptrdiff_t; |
1198 | using value_type = |
1199 | typename std::conditional<IsConst, const Bucket, Bucket>::type; |
1200 | using pointer = value_type *; |
1201 | using reference = value_type &; |
1202 | using iterator_category = std::forward_iterator_tag; |
1203 | |
1204 | private: |
1205 | pointer Ptr = nullptr; |
1206 | pointer End = nullptr; |
1207 | |
1208 | public: |
1209 | DenseMapIterator() = default; |
1210 | |
1211 | DenseMapIterator(pointer Pos, pointer E, const DebugEpochBase &Epoch, |
1212 | bool NoAdvance = false) |
1213 | : DebugEpochBase::HandleBase(&Epoch), Ptr(Pos), End(E) { |
1214 | assert(isHandleInSync() && "invalid construction!")((void)0); |
1215 | |
1216 | if (NoAdvance) return; |
1217 | if (shouldReverseIterate<KeyT>()) { |
1218 | RetreatPastEmptyBuckets(); |
1219 | return; |
1220 | } |
1221 | AdvancePastEmptyBuckets(); |
1222 | } |
1223 | |
1224 | // Converting ctor from non-const iterators to const iterators. SFINAE'd out |
1225 | // for const iterator destinations so it doesn't end up as a user defined copy |
1226 | // constructor. |
1227 | template <bool IsConstSrc, |
1228 | typename = std::enable_if_t<!IsConstSrc && IsConst>> |
1229 | DenseMapIterator( |
1230 | const DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, IsConstSrc> &I) |
1231 | : DebugEpochBase::HandleBase(I), Ptr(I.Ptr), End(I.End) {} |
1232 | |
1233 | reference operator*() const { |
1234 | assert(isHandleInSync() && "invalid iterator access!")((void)0); |
1235 | assert(Ptr != End && "dereferencing end() iterator")((void)0); |
1236 | if (shouldReverseIterate<KeyT>()) |
1237 | return Ptr[-1]; |
1238 | return *Ptr; |
1239 | } |
1240 | pointer operator->() const { |
1241 | assert(isHandleInSync() && "invalid iterator access!")((void)0); |
1242 | assert(Ptr != End && "dereferencing end() iterator")((void)0); |
1243 | if (shouldReverseIterate<KeyT>()) |
1244 | return &(Ptr[-1]); |
1245 | return Ptr; |
1246 | } |
1247 | |
1248 | friend bool operator==(const DenseMapIterator &LHS, |
1249 | const DenseMapIterator &RHS) { |
1250 | assert((!LHS.Ptr || LHS.isHandleInSync()) && "handle not in sync!")((void)0); |
1251 | assert((!RHS.Ptr || RHS.isHandleInSync()) && "handle not in sync!")((void)0); |
1252 | assert(LHS.getEpochAddress() == RHS.getEpochAddress() &&((void)0) |
1253 | "comparing incomparable iterators!")((void)0); |
1254 | return LHS.Ptr == RHS.Ptr; |
1255 | } |
1256 | |
1257 | friend bool operator!=(const DenseMapIterator &LHS, |
1258 | const DenseMapIterator &RHS) { |
1259 | return !(LHS == RHS); |
1260 | } |
1261 | |
1262 | inline DenseMapIterator& operator++() { // Preincrement |
1263 | assert(isHandleInSync() && "invalid iterator access!")((void)0); |
1264 | assert(Ptr != End && "incrementing end() iterator")((void)0); |
1265 | if (shouldReverseIterate<KeyT>()) { |
1266 | --Ptr; |
1267 | RetreatPastEmptyBuckets(); |
1268 | return *this; |
1269 | } |
1270 | ++Ptr; |
1271 | AdvancePastEmptyBuckets(); |
1272 | return *this; |
1273 | } |
1274 | DenseMapIterator operator++(int) { // Postincrement |
1275 | assert(isHandleInSync() && "invalid iterator access!")((void)0); |
1276 | DenseMapIterator tmp = *this; ++*this; return tmp; |
1277 | } |
1278 | |
1279 | private: |
1280 | void AdvancePastEmptyBuckets() { |
1281 | assert(Ptr <= End)((void)0); |
1282 | const KeyT Empty = KeyInfoT::getEmptyKey(); |
1283 | const KeyT Tombstone = KeyInfoT::getTombstoneKey(); |
1284 | |
1285 | while (Ptr != End && (KeyInfoT::isEqual(Ptr->getFirst(), Empty) || |
1286 | KeyInfoT::isEqual(Ptr->getFirst(), Tombstone))) |
1287 | ++Ptr; |
1288 | } |
1289 | |
1290 | void RetreatPastEmptyBuckets() { |
1291 | assert(Ptr >= End)((void)0); |
1292 | const KeyT Empty = KeyInfoT::getEmptyKey(); |
1293 | const KeyT Tombstone = KeyInfoT::getTombstoneKey(); |
1294 | |
1295 | while (Ptr != End && (KeyInfoT::isEqual(Ptr[-1].getFirst(), Empty) || |
1296 | KeyInfoT::isEqual(Ptr[-1].getFirst(), Tombstone))) |
1297 | --Ptr; |
1298 | } |
1299 | }; |
1300 | |
1301 | template <typename KeyT, typename ValueT, typename KeyInfoT> |
1302 | inline size_t capacity_in_bytes(const DenseMap<KeyT, ValueT, KeyInfoT> &X) { |
1303 | return X.getMemorySize(); |
1304 | } |
1305 | |
1306 | } // end namespace llvm |
1307 | |
1308 | #endif // LLVM_ADT_DENSEMAP_H |