1//===- Tracker.cpp --------------------------------------------------------===//
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#include "llvm/SandboxIR/Tracker.h"
10#include "llvm/ADT/STLExtras.h"
11#include "llvm/IR/BasicBlock.h"
12#include "llvm/IR/Instruction.h"
13#include "llvm/IR/StructuralHash.h"
14#include "llvm/SandboxIR/Instruction.h"
15
16using namespace llvm::sandboxir;
17
18#ifndef NDEBUG
19
20std::string IRSnapshotChecker::dumpIR(const llvm::Function &F) const {
21 std::string Result;
22 raw_string_ostream SS(Result);
23 F.print(SS, /*AssemblyAnnotationWriter=*/nullptr);
24 return Result;
25}
26
27IRSnapshotChecker::ContextSnapshot IRSnapshotChecker::takeSnapshot() const {
28 ContextSnapshot Result;
29 for (const auto &Entry : Ctx.LLVMModuleToModuleMap)
30 for (const auto &F : *Entry.first) {
31 FunctionSnapshot Snapshot;
32 Snapshot.Hash = StructuralHash(F, /*DetailedHash=*/true);
33 Snapshot.TextualIR = dumpIR(F);
34 Result[&F] = Snapshot;
35 }
36 return Result;
37}
38
39bool IRSnapshotChecker::diff(const ContextSnapshot &Orig,
40 const ContextSnapshot &Curr) const {
41 bool DifferenceFound = false;
42 for (const auto &[F, OrigFS] : Orig) {
43 auto CurrFSIt = Curr.find(F);
44 if (CurrFSIt == Curr.end()) {
45 DifferenceFound = true;
46 dbgs() << "Function " << F->getName() << " not found in current IR.\n";
47 dbgs() << OrigFS.TextualIR << "\n";
48 continue;
49 }
50 const FunctionSnapshot &CurrFS = CurrFSIt->second;
51 if (OrigFS.Hash != CurrFS.Hash) {
52 DifferenceFound = true;
53 dbgs() << "Found IR difference in Function " << F->getName() << "\n";
54 dbgs() << "Original:\n" << OrigFS.TextualIR << "\n";
55 dbgs() << "Current:\n" << CurrFS.TextualIR << "\n";
56 }
57 }
58 // Check that Curr doesn't contain any new functions.
59 for (const auto &[F, CurrFS] : Curr) {
60 if (!Orig.contains(F)) {
61 DifferenceFound = true;
62 dbgs() << "Function " << F->getName()
63 << " found in current IR but not in original snapshot.\n";
64 dbgs() << CurrFS.TextualIR << "\n";
65 }
66 }
67 return DifferenceFound;
68}
69
70void IRSnapshotChecker::save() { OrigContextSnapshot = takeSnapshot(); }
71
72void IRSnapshotChecker::expectNoDiff() {
73 ContextSnapshot CurrContextSnapshot = takeSnapshot();
74 if (diff(OrigContextSnapshot, CurrContextSnapshot)) {
75 llvm_unreachable(
76 "Original and current IR differ! Probably a checkpointing bug.");
77 }
78}
79
80void UseSet::dump() const {
81 dump(dbgs());
82 dbgs() << "\n";
83}
84
85void UseSwap::dump() const {
86 dump(dbgs());
87 dbgs() << "\n";
88}
89#endif // NDEBUG
90
91PHIRemoveIncoming::PHIRemoveIncoming(PHINode *PHI, unsigned RemovedIdx)
92 : PHI(PHI), RemovedIdx(RemovedIdx) {
93 RemovedV = PHI->getIncomingValue(Idx: RemovedIdx);
94 RemovedBB = PHI->getIncomingBlock(Idx: RemovedIdx);
95}
96
97void PHIRemoveIncoming::revert(Tracker &Tracker) {
98 // Special case: if the PHI is now empty, as we don't need to care about the
99 // order of the incoming values.
100 unsigned NumIncoming = PHI->getNumIncomingValues();
101 if (NumIncoming == 0) {
102 PHI->addIncoming(V: RemovedV, BB: RemovedBB);
103 return;
104 }
105 // Shift all incoming values by one starting from the end until `Idx`.
106 // Start by adding a copy of the last incoming values.
107 unsigned LastIdx = NumIncoming - 1;
108 PHI->addIncoming(V: PHI->getIncomingValue(Idx: LastIdx),
109 BB: PHI->getIncomingBlock(Idx: LastIdx));
110 for (unsigned Idx = LastIdx; Idx > RemovedIdx; --Idx) {
111 auto *PrevV = PHI->getIncomingValue(Idx: Idx - 1);
112 auto *PrevBB = PHI->getIncomingBlock(Idx: Idx - 1);
113 PHI->setIncomingValue(Idx, V: PrevV);
114 PHI->setIncomingBlock(Idx, BB: PrevBB);
115 }
116 PHI->setIncomingValue(Idx: RemovedIdx, V: RemovedV);
117 PHI->setIncomingBlock(Idx: RemovedIdx, BB: RemovedBB);
118}
119
120#ifndef NDEBUG
121void PHIRemoveIncoming::dump() const {
122 dump(dbgs());
123 dbgs() << "\n";
124}
125#endif // NDEBUG
126
127PHIAddIncoming::PHIAddIncoming(PHINode *PHI)
128 : PHI(PHI), Idx(PHI->getNumIncomingValues()) {}
129
130void PHIAddIncoming::revert(Tracker &Tracker) { PHI->removeIncomingValue(Idx); }
131
132#ifndef NDEBUG
133void PHIAddIncoming::dump() const {
134 dump(dbgs());
135 dbgs() << "\n";
136}
137#endif // NDEBUG
138
139Tracker::~Tracker() {
140 assert(Changes.empty() && "You must accept or revert changes!");
141}
142
143EraseFromParent::EraseFromParent(std::unique_ptr<sandboxir::Value> &&ErasedIPtr)
144 : ErasedIPtr(std::move(ErasedIPtr)) {
145 auto *I = cast<Instruction>(Val: this->ErasedIPtr.get());
146 auto LLVMInstrs = I->getLLVMInstrs();
147 // Iterate in reverse program order.
148 for (auto *LLVMI : reverse(C&: LLVMInstrs)) {
149 SmallVector<llvm::Value *> Operands;
150 Operands.reserve(N: LLVMI->getNumOperands());
151 for (auto [OpNum, Use] : enumerate(First: LLVMI->operands()))
152 Operands.push_back(Elt: Use.get());
153 InstrData.push_back(Elt: {.Operands: Operands, .LLVMI: LLVMI});
154 }
155 assert(is_sorted(InstrData,
156 [](const auto &D0, const auto &D1) {
157 return D0.LLVMI->comesBefore(D1.LLVMI);
158 }) &&
159 "Expected reverse program order!");
160 auto *BotLLVMI = cast<llvm::Instruction>(Val: I->Val);
161 if (BotLLVMI->getNextNode() != nullptr)
162 NextLLVMIOrBB = BotLLVMI->getNextNode();
163 else
164 NextLLVMIOrBB = BotLLVMI->getParent();
165}
166
167void EraseFromParent::accept() {
168 for (const auto &IData : InstrData)
169 IData.LLVMI->deleteValue();
170}
171
172void EraseFromParent::revert(Tracker &Tracker) {
173 // Place the bottom-most instruction first.
174 auto [Operands, BotLLVMI] = InstrData[0];
175 if (auto *NextLLVMI = dyn_cast<llvm::Instruction *>(Val&: NextLLVMIOrBB)) {
176 BotLLVMI->insertBefore(InsertPos: NextLLVMI->getIterator());
177 } else {
178 auto *LLVMBB = cast<llvm::BasicBlock *>(Val&: NextLLVMIOrBB);
179 BotLLVMI->insertInto(ParentBB: LLVMBB, It: LLVMBB->end());
180 }
181 for (auto [OpNum, Op] : enumerate(First&: Operands))
182 BotLLVMI->setOperand(i: OpNum, Val: Op);
183
184 // Go over the rest of the instructions and stack them on top.
185 for (auto [Operands, LLVMI] : drop_begin(RangeOrContainer&: InstrData)) {
186 LLVMI->insertBefore(InsertPos: BotLLVMI->getIterator());
187 for (auto [OpNum, Op] : enumerate(First&: Operands))
188 LLVMI->setOperand(i: OpNum, Val: Op);
189 BotLLVMI = LLVMI;
190 }
191 Tracker.getContext().registerValue(VPtr: std::move(ErasedIPtr));
192}
193
194#ifndef NDEBUG
195void EraseFromParent::dump() const {
196 dump(dbgs());
197 dbgs() << "\n";
198}
199#endif // NDEBUG
200
201RemoveFromParent::RemoveFromParent(Instruction *RemovedI) : RemovedI(RemovedI) {
202 if (auto *NextI = RemovedI->getNextNode())
203 NextInstrOrBB = NextI;
204 else
205 NextInstrOrBB = RemovedI->getParent();
206}
207
208void RemoveFromParent::revert(Tracker &Tracker) {
209 if (auto *NextI = dyn_cast<Instruction *>(Val&: NextInstrOrBB)) {
210 RemovedI->insertBefore(BeforeI: NextI);
211 } else {
212 auto *BB = cast<BasicBlock *>(Val&: NextInstrOrBB);
213 RemovedI->insertInto(BB, WhereIt: BB->end());
214 }
215}
216
217#ifndef NDEBUG
218void RemoveFromParent::dump() const {
219 dump(dbgs());
220 dbgs() << "\n";
221}
222#endif
223
224CatchSwitchAddHandler::CatchSwitchAddHandler(CatchSwitchInst *CSI)
225 : CSI(CSI), HandlerIdx(CSI->getNumHandlers()) {}
226
227void CatchSwitchAddHandler::revert(Tracker &Tracker) {
228 // TODO: This should ideally use sandboxir::CatchSwitchInst::removeHandler()
229 // once it gets implemented.
230 auto *LLVMCSI = cast<llvm::CatchSwitchInst>(Val: CSI->Val);
231 LLVMCSI->removeHandler(HI: LLVMCSI->handler_begin() + HandlerIdx);
232}
233
234SwitchRemoveCase::SwitchRemoveCase(SwitchInst *Switch) : Switch(Switch) {
235 for (const auto &C : Switch->cases())
236 Cases.push_back(Elt: {.Val: C.getCaseValue(), .Dest: C.getCaseSuccessor()});
237}
238
239void SwitchRemoveCase::revert(Tracker &Tracker) {
240 // SwitchInst::removeCase doesn't provide any guarantees about the order of
241 // cases after removal. In order to preserve the original ordering, we save
242 // all of them and, when reverting, clear them all then insert them in the
243 // desired order. This still relies on the fact that `addCase` will insert
244 // them at the end, but it is documented to invalidate `case_end()` so it's
245 // probably okay.
246 unsigned NumCases = Switch->getNumCases();
247 for (unsigned I = 0; I < NumCases; ++I)
248 Switch->removeCase(It: Switch->case_begin());
249 for (auto &Case : Cases)
250 Switch->addCase(OnVal: Case.Val, Dest: Case.Dest);
251}
252
253#ifndef NDEBUG
254void SwitchRemoveCase::dump() const {
255 dump(dbgs());
256 dbgs() << "\n";
257}
258#endif // NDEBUG
259
260void SwitchAddCase::revert(Tracker &Tracker) {
261 auto It = Switch->findCaseValue(C: Val);
262 Switch->removeCase(It);
263}
264
265#ifndef NDEBUG
266void SwitchAddCase::dump() const {
267 dump(dbgs());
268 dbgs() << "\n";
269}
270#endif // NDEBUG
271
272MoveInstr::MoveInstr(Instruction *MovedI) : MovedI(MovedI) {
273 if (auto *NextI = MovedI->getNextNode())
274 NextInstrOrBB = NextI;
275 else
276 NextInstrOrBB = MovedI->getParent();
277}
278
279void MoveInstr::revert(Tracker &Tracker) {
280 if (auto *NextI = dyn_cast<Instruction *>(Val&: NextInstrOrBB)) {
281 MovedI->moveBefore(Before: NextI);
282 } else {
283 auto *BB = cast<BasicBlock *>(Val&: NextInstrOrBB);
284 MovedI->moveBefore(BB&: *BB, WhereIt: BB->end());
285 }
286}
287
288#ifndef NDEBUG
289void MoveInstr::dump() const {
290 dump(dbgs());
291 dbgs() << "\n";
292}
293#endif
294
295void InsertIntoBB::revert(Tracker &Tracker) { InsertedI->removeFromParent(); }
296
297InsertIntoBB::InsertIntoBB(Instruction *InsertedI) : InsertedI(InsertedI) {}
298
299#ifndef NDEBUG
300void InsertIntoBB::dump() const {
301 dump(dbgs());
302 dbgs() << "\n";
303}
304#endif
305
306void CreateAndInsertInst::revert(Tracker &Tracker) { NewI->eraseFromParent(); }
307
308#ifndef NDEBUG
309void CreateAndInsertInst::dump() const {
310 dump(dbgs());
311 dbgs() << "\n";
312}
313#endif
314
315ShuffleVectorSetMask::ShuffleVectorSetMask(ShuffleVectorInst *SVI)
316 : SVI(SVI), PrevMask(SVI->getShuffleMask()) {}
317
318void ShuffleVectorSetMask::revert(Tracker &Tracker) {
319 SVI->setShuffleMask(PrevMask);
320}
321
322#ifndef NDEBUG
323void ShuffleVectorSetMask::dump() const {
324 dump(dbgs());
325 dbgs() << "\n";
326}
327#endif
328
329CmpSwapOperands::CmpSwapOperands(CmpInst *Cmp) : Cmp(Cmp) {}
330
331void CmpSwapOperands::revert(Tracker &Tracker) { Cmp->swapOperands(); }
332#ifndef NDEBUG
333void CmpSwapOperands::dump() const {
334 dump(dbgs());
335 dbgs() << "\n";
336}
337#endif
338
339void Tracker::save() {
340 State = TrackerState::Record;
341#if !defined(NDEBUG) && defined(EXPENSIVE_CHECKS)
342 SnapshotChecker.save();
343#endif
344}
345
346void Tracker::revert() {
347 assert(State == TrackerState::Record && "Forgot to save()!");
348 State = TrackerState::Reverting;
349 for (auto &Change : reverse(C&: Changes))
350 Change->revert(Tracker&: *this);
351 Changes.clear();
352#if !defined(NDEBUG) && defined(EXPENSIVE_CHECKS)
353 SnapshotChecker.expectNoDiff();
354#endif
355 State = TrackerState::Disabled;
356}
357
358void Tracker::accept() {
359 assert(State == TrackerState::Record && "Forgot to save()!");
360 State = TrackerState::Disabled;
361 for (auto &Change : Changes)
362 Change->accept();
363 Changes.clear();
364}
365
366#ifndef NDEBUG
367void Tracker::dump(raw_ostream &OS) const {
368 for (auto [Idx, ChangePtr] : enumerate(Changes)) {
369 OS << Idx << ". ";
370 ChangePtr->dump(OS);
371 OS << "\n";
372 }
373}
374void Tracker::dump() const {
375 dump(dbgs());
376 dbgs() << "\n";
377}
378#endif // NDEBUG
379