1//===- bolt/Passes/FrameAnalysis.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// This file implements the FrameAnalysis class.
10//
11//===----------------------------------------------------------------------===//
12
13#include "bolt/Passes/FrameAnalysis.h"
14#include "bolt/Core/CallGraphWalker.h"
15#include "bolt/Core/ParallelUtilities.h"
16#include "llvm/MC/MCRegisterInfo.h"
17#include "llvm/Support/Timer.h"
18#include <fstream>
19#include <stack>
20
21#define DEBUG_TYPE "fa"
22
23using namespace llvm;
24
25namespace opts {
26extern cl::OptionCategory BoltOptCategory;
27extern cl::opt<unsigned> Verbosity;
28
29static cl::list<std::string>
30 FrameOptFunctionNames("funcs-fop", cl::CommaSeparated,
31 cl::desc("list of functions to apply frame opts"),
32 cl::value_desc("func1,func2,func3,..."));
33
34static cl::opt<std::string> FrameOptFunctionNamesFile(
35 "funcs-file-fop",
36 cl::desc("file with list of functions to frame optimize"));
37
38static cl::opt<bool> TimeFA("time-fa", cl::desc("time frame analysis steps"),
39 cl::ReallyHidden, cl::cat(BoltOptCategory));
40
41static cl::opt<bool>
42 ExperimentalSW("experimental-shrink-wrapping",
43 cl::desc("process functions with stack pointer arithmetic"),
44 cl::ReallyHidden, cl::ZeroOrMore, cl::cat(BoltOptCategory));
45
46bool shouldFrameOptimize(const llvm::bolt::BinaryFunction &Function) {
47 if (Function.hasUnknownControlFlow())
48 return false;
49
50 if (!FrameOptFunctionNamesFile.empty()) {
51 assert(!FrameOptFunctionNamesFile.empty() && "unexpected empty file name");
52 std::ifstream FuncsFile(FrameOptFunctionNamesFile, std::ios::in);
53 std::string FuncName;
54 while (std::getline(is&: FuncsFile, str&: FuncName))
55 FrameOptFunctionNames.push_back(value: FuncName);
56 FrameOptFunctionNamesFile = "";
57 }
58
59 if (FrameOptFunctionNames.empty())
60 return true;
61 return llvm::any_of(Range&: FrameOptFunctionNames, P: [&](std::string &Name) {
62 return Function.hasName(FunctionName: Name);
63 });
64}
65} // namespace opts
66
67namespace llvm {
68namespace bolt {
69
70raw_ostream &operator<<(raw_ostream &OS, const FrameIndexEntry &FIE) {
71 OS << "FrameIndexEntry<IsLoad: " << FIE.IsLoad << ", IsStore: " << FIE.IsStore
72 << ", IsStoreFromReg: " << FIE.IsStoreFromReg
73 << ", RegOrImm: " << FIE.RegOrImm << ", StackOffset: ";
74 if (FIE.StackOffset < 0)
75 OS << "-" << Twine::utohexstr(Val: -FIE.StackOffset);
76 else
77 OS << "+" << Twine::utohexstr(Val: FIE.StackOffset);
78 OS << ", Size: " << static_cast<int>(FIE.Size)
79 << ", IsSimple: " << FIE.IsSimple << ">";
80 return OS;
81}
82
83namespace {
84
85/// This class should be used to iterate through basic blocks in layout order
86/// to analyze instructions for frame accesses. The user should call
87/// enterNewBB() whenever starting analyzing a new BB and doNext() for each
88/// instruction. After doNext(), if isValidAccess() returns true, it means the
89/// current instruction accesses the frame and getFIE() may be used to obtain
90/// details about this access.
91class FrameAccessAnalysis {
92 /// We depend on Stack Pointer Tracking to figure out the current SP offset
93 /// value at a given program point
94 StackPointerTracking &SPT;
95
96 /// Context vars
97 const BinaryContext &BC;
98 const BinaryFunction &BF;
99 // Vars used for storing useful CFI info to give us a hint about how the stack
100 // is used in this function
101 int SPOffset{0};
102 int FPOffset{0};
103 int64_t CfaOffset{-8};
104 uint16_t CfaReg{7};
105 std::stack<std::pair<int64_t, uint16_t>> CFIStack;
106 /// Our pointer to access SPT info
107 const MCInst *Prev{nullptr};
108 /// Info about the last frame access
109 bool IsValidAccess{false};
110 bool EscapesStackAddress{false};
111 FrameIndexEntry FIE;
112
113 bool decodeFrameAccess(const MCInst &Inst) {
114 int32_t SrcImm = 0;
115 MCPhysReg Reg = 0;
116 int64_t StackOffset = 0;
117 bool IsIndexed = false;
118 if (!BC.MIB->isStackAccess(
119 Inst, IsLoad&: FIE.IsLoad, IsStore&: FIE.IsStore, IsStoreFromReg&: FIE.IsStoreFromReg, Reg, SrcImm,
120 StackPtrReg&: FIE.StackPtrReg, StackOffset, Size&: FIE.Size, IsSimple&: FIE.IsSimple, IsIndexed)) {
121 return true;
122 }
123
124 if (IsIndexed || (!FIE.Size && (FIE.IsLoad || FIE.IsStore))) {
125 LLVM_DEBUG(dbgs() << "Giving up on indexed memory access/unknown size\n");
126 LLVM_DEBUG(dbgs() << "Blame insn: ");
127 LLVM_DEBUG(BC.printInstruction(dbgs(), Inst, 0, &BF, true, false, false));
128 LLVM_DEBUG(Inst.dump());
129 return false;
130 }
131
132 assert(FIE.Size != 0 || (!FIE.IsLoad && !FIE.IsStore));
133
134 FIE.RegOrImm = SrcImm;
135 if (FIE.IsLoad || FIE.IsStoreFromReg)
136 FIE.RegOrImm = Reg;
137
138 if (FIE.StackPtrReg == BC.MIB->getStackPointer() && SPOffset != SPT.EMPTY &&
139 SPOffset != SPT.SUPERPOSITION) {
140 LLVM_DEBUG(
141 dbgs() << "Adding access via SP while CFA reg is another one\n");
142 FIE.StackOffset = SPOffset + StackOffset;
143 } else if (FIE.StackPtrReg == BC.MIB->getFramePointer() &&
144 FPOffset != SPT.EMPTY && FPOffset != SPT.SUPERPOSITION) {
145 LLVM_DEBUG(
146 dbgs() << "Adding access via FP while CFA reg is another one\n");
147 FIE.StackOffset = FPOffset + StackOffset;
148 } else if (FIE.StackPtrReg ==
149 *BC.MRI->getLLVMRegNum(RegNum: CfaReg, /*isEH=*/false)) {
150 FIE.StackOffset = CfaOffset + StackOffset;
151 } else {
152 LLVM_DEBUG(
153 dbgs() << "Found stack access with reg different than cfa reg.\n");
154 LLVM_DEBUG(dbgs() << "\tCurrent CFA reg: " << CfaReg
155 << "\n\tStack access reg: " << FIE.StackPtrReg << "\n");
156 LLVM_DEBUG(dbgs() << "Blame insn: ");
157 LLVM_DEBUG(Inst.dump());
158 return false;
159 }
160 IsValidAccess = true;
161 return true;
162 }
163
164public:
165 FrameAccessAnalysis(BinaryFunction &BF, StackPointerTracking &SPT)
166 : SPT(SPT), BC(BF.getBinaryContext()), BF(BF) {}
167
168 void enterNewBB() { Prev = nullptr; }
169 const FrameIndexEntry &getFIE() const { return FIE; }
170 int getSPOffset() const { return SPOffset; }
171 bool isValidAccess() const { return IsValidAccess; }
172 bool doesEscapeStackAddress() const { return EscapesStackAddress; }
173
174 bool doNext(const BinaryBasicBlock &BB, const MCInst &Inst) {
175 IsValidAccess = false;
176 EscapesStackAddress = false;
177 std::tie(args&: SPOffset, args&: FPOffset) =
178 Prev ? *SPT.getStateAt(Point: *Prev) : *SPT.getStateAt(BB);
179 Prev = &Inst;
180 // Use CFI information to keep track of which register is being used to
181 // access the frame
182 if (BC.MIB->isCFI(Inst)) {
183 const MCCFIInstruction *CFI = BF.getCFIFor(Instr: Inst);
184 switch (CFI->getOperation()) {
185 case MCCFIInstruction::OpDefCfa:
186 CfaOffset = CFI->getOffset();
187 [[fallthrough]];
188 case MCCFIInstruction::OpDefCfaRegister:
189 CfaReg = CFI->getRegister();
190 break;
191 case MCCFIInstruction::OpDefCfaOffset:
192 CfaOffset = CFI->getOffset();
193 break;
194 case MCCFIInstruction::OpRememberState:
195 CFIStack.push(x: std::make_pair(x&: CfaOffset, y&: CfaReg));
196 break;
197 case MCCFIInstruction::OpRestoreState: {
198 if (CFIStack.empty())
199 dbgs() << "Assertion is about to fail: " << BF.getPrintName() << "\n";
200 assert(!CFIStack.empty() && "Corrupt CFI stack");
201 std::pair<int64_t, uint16_t> &Elem = CFIStack.top();
202 CFIStack.pop();
203 CfaOffset = Elem.first;
204 CfaReg = Elem.second;
205 break;
206 }
207 case MCCFIInstruction::OpAdjustCfaOffset:
208 llvm_unreachable("Unhandled AdjustCfaOffset");
209 break;
210 default:
211 break;
212 }
213 return true;
214 }
215
216 if (BC.MIB->escapesVariable(Inst, HasFramePointer: SPT.HasFramePointer)) {
217 EscapesStackAddress = true;
218 if (!opts::ExperimentalSW) {
219 LLVM_DEBUG(
220 dbgs() << "Leaked stack address, giving up on this function.\n");
221 LLVM_DEBUG(dbgs() << "Blame insn: ");
222 LLVM_DEBUG(Inst.dump());
223 return false;
224 }
225 }
226
227 return decodeFrameAccess(Inst);
228 }
229};
230
231} // end anonymous namespace
232
233void FrameAnalysis::addArgAccessesFor(MCInst &Inst, ArgAccesses &&AA) {
234 if (ErrorOr<ArgAccesses &> OldAA = getArgAccessesFor(Inst)) {
235 if (OldAA->AssumeEverything)
236 return;
237 *OldAA = std::move(AA);
238 return;
239 }
240 if (AA.AssumeEverything) {
241 // Index 0 in ArgAccessesVector represents an "assumeeverything" entry
242 BC.MIB->addAnnotation(Inst, Name: "ArgAccessEntry", Val: 0U);
243 return;
244 }
245 BC.MIB->addAnnotation(Inst, Name: "ArgAccessEntry",
246 Val: (unsigned)ArgAccessesVector.size());
247 ArgAccessesVector.emplace_back(args: std::move(AA));
248}
249
250void FrameAnalysis::addArgInStackAccessFor(MCInst &Inst,
251 const ArgInStackAccess &Arg) {
252 ErrorOr<ArgAccesses &> AA = getArgAccessesFor(Inst);
253 if (!AA) {
254 addArgAccessesFor(Inst, AA: ArgAccesses(false));
255 AA = getArgAccessesFor(Inst);
256 assert(AA && "Object setup failed");
257 }
258 std::set<ArgInStackAccess> &Set = AA->Set;
259 assert(!AA->AssumeEverything && "Adding arg to AssumeEverything set");
260 Set.emplace(args: Arg);
261}
262
263void FrameAnalysis::addFIEFor(MCInst &Inst, const FrameIndexEntry &FIE) {
264 BC.MIB->addAnnotation(Inst, Name: "FrameAccessEntry", Val: (unsigned)FIEVector.size());
265 FIEVector.emplace_back(args: FIE);
266}
267
268ErrorOr<ArgAccesses &> FrameAnalysis::getArgAccessesFor(const MCInst &Inst) {
269 if (auto Idx = BC.MIB->tryGetAnnotationAs<unsigned>(Inst, Name: "ArgAccessEntry")) {
270 assert(ArgAccessesVector.size() > *Idx && "Out of bounds");
271 return ArgAccessesVector[*Idx];
272 }
273 return make_error_code(E: errc::result_out_of_range);
274}
275
276ErrorOr<const ArgAccesses &>
277FrameAnalysis::getArgAccessesFor(const MCInst &Inst) const {
278 if (auto Idx = BC.MIB->tryGetAnnotationAs<unsigned>(Inst, Name: "ArgAccessEntry")) {
279 assert(ArgAccessesVector.size() > *Idx && "Out of bounds");
280 return ArgAccessesVector[*Idx];
281 }
282 return make_error_code(E: errc::result_out_of_range);
283}
284
285ErrorOr<const FrameIndexEntry &>
286FrameAnalysis::getFIEFor(const MCInst &Inst) const {
287 if (auto Idx =
288 BC.MIB->tryGetAnnotationAs<unsigned>(Inst, Name: "FrameAccessEntry")) {
289 assert(FIEVector.size() > *Idx && "Out of bounds");
290 return FIEVector[*Idx];
291 }
292 return make_error_code(E: errc::result_out_of_range);
293}
294
295void FrameAnalysis::traverseCG(BinaryFunctionCallGraph &CG) {
296 CallGraphWalker CGWalker(CG);
297
298 CGWalker.registerVisitor(
299 Callback: [&](BinaryFunction *Func) -> bool { return computeArgsAccessed(BF&: *Func); });
300
301 CGWalker.walk();
302
303 DEBUG_WITH_TYPE("ra", {
304 for (auto &MapEntry : ArgsTouchedMap) {
305 const BinaryFunction *Func = MapEntry.first;
306 const auto &Set = MapEntry.second;
307 dbgs() << "Args accessed for " << Func->getPrintName() << ": ";
308 if (!Set.empty() && Set.count(std::make_pair(-1, 0)))
309 dbgs() << "assume everything";
310 else
311 for (const std::pair<int64_t, uint8_t> &Entry : Set)
312 dbgs() << "[" << Entry.first << ", " << (int)Entry.second << "] ";
313 dbgs() << "\n";
314 }
315 });
316}
317
318bool FrameAnalysis::updateArgsTouchedFor(const BinaryFunction &BF, MCInst &Inst,
319 int CurOffset) {
320 if (!BC.MIB->isCall(Inst))
321 return false;
322
323 const MCSymbol *TargetSymbol = BC.MIB->getTargetSymbol(Inst);
324 // If indirect call, we conservatively assume it accesses all stack positions
325 if (TargetSymbol == nullptr) {
326 addArgAccessesFor(Inst, AA: ArgAccesses(/*AssumeEverything=*/true));
327 if (!FunctionsRequireAlignment.count(V: &BF)) {
328 FunctionsRequireAlignment.insert(V: &BF);
329 return true;
330 }
331 return false;
332 }
333
334 const BinaryFunction *Function = BC.getFunctionForSymbol(Symbol: TargetSymbol);
335 // Call to a function without a BinaryFunction object. Conservatively assume
336 // it accesses all stack positions
337 if (Function == nullptr) {
338 addArgAccessesFor(Inst, AA: ArgAccesses(/*AssumeEverything=*/true));
339 if (!FunctionsRequireAlignment.count(V: &BF)) {
340 FunctionsRequireAlignment.insert(V: &BF);
341 return true;
342 }
343 return false;
344 }
345
346 auto Iter = ArgsTouchedMap.find(x: Function);
347
348 bool Changed = false;
349 if (BC.MIB->isTailCall(Inst) && Iter != ArgsTouchedMap.end()) {
350 // Ignore checking CurOffset because we can't always reliably determine the
351 // offset specially after an epilogue, where tailcalls happen. It should be
352 // -8.
353 for (std::pair<int64_t, uint8_t> Elem : Iter->second) {
354 if (!llvm::is_contained(Range&: ArgsTouchedMap[&BF], Element: Elem)) {
355 ArgsTouchedMap[&BF].emplace(args&: Elem);
356 Changed = true;
357 }
358 }
359 }
360 if (FunctionsRequireAlignment.count(V: Function) &&
361 !FunctionsRequireAlignment.count(V: &BF)) {
362 Changed = true;
363 FunctionsRequireAlignment.insert(V: &BF);
364 }
365 if (Iter == ArgsTouchedMap.end())
366 return Changed;
367
368 if (CurOffset == StackPointerTracking::EMPTY ||
369 CurOffset == StackPointerTracking::SUPERPOSITION) {
370 addArgAccessesFor(Inst, AA: ArgAccesses(/*AssumeEverything=*/true));
371 return Changed;
372 }
373
374 for (std::pair<int64_t, uint8_t> Elem : Iter->second) {
375 if (Elem.first == -1) {
376 addArgAccessesFor(Inst, AA: ArgAccesses(/*AssumeEverything=*/true));
377 break;
378 }
379 LLVM_DEBUG(dbgs() << "Added arg in stack access annotation "
380 << CurOffset + Elem.first << "\n");
381 addArgInStackAccessFor(
382 Inst, Arg: ArgInStackAccess{/*StackOffset=*/CurOffset + Elem.first,
383 /*Size=*/Elem.second});
384 }
385 return Changed;
386}
387
388bool FrameAnalysis::computeArgsAccessed(BinaryFunction &BF) {
389 if (!BF.isSimple() || !BF.hasCFG()) {
390 LLVM_DEBUG(dbgs() << "Treating " << BF.getPrintName()
391 << " conservatively.\n");
392 ArgsTouchedMap[&BF].emplace(args: std::make_pair(x: -1, y: 0));
393 if (!FunctionsRequireAlignment.count(V: &BF)) {
394 FunctionsRequireAlignment.insert(V: &BF);
395 return true;
396 }
397 return false;
398 }
399
400 LLVM_DEBUG(dbgs() << "Now computing args accessed for: " << BF.getPrintName()
401 << "\n");
402 bool UpdatedArgsTouched = false;
403 bool NoInfo = false;
404 FrameAccessAnalysis FAA(BF, getSPT(BF));
405
406 for (BinaryBasicBlock *BB : BF.getLayout().blocks()) {
407 FAA.enterNewBB();
408
409 for (MCInst &Inst : *BB) {
410 if (!FAA.doNext(BB: *BB, Inst) || FAA.doesEscapeStackAddress()) {
411 ArgsTouchedMap[&BF].emplace(args: std::make_pair(x: -1, y: 0));
412 NoInfo = true;
413 break;
414 }
415
416 // Check for calls -- attach stack accessing info to them regarding their
417 // target
418 if (updateArgsTouchedFor(BF, Inst, CurOffset: FAA.getSPOffset()))
419 UpdatedArgsTouched = true;
420
421 // Check for stack accesses that affect callers
422 if (!FAA.isValidAccess())
423 continue;
424
425 const FrameIndexEntry &FIE = FAA.getFIE();
426 if (FIE.StackOffset < 0)
427 continue;
428 if (ArgsTouchedMap[&BF].find(x: std::make_pair(x: FIE.StackOffset, y: FIE.Size)) !=
429 ArgsTouchedMap[&BF].end())
430 continue;
431
432 // Record accesses to the previous stack frame
433 ArgsTouchedMap[&BF].emplace(args: std::make_pair(x: FIE.StackOffset, y: FIE.Size));
434 UpdatedArgsTouched = true;
435 LLVM_DEBUG({
436 dbgs() << "Arg access offset " << FIE.StackOffset << " added to:\n";
437 BC.printInstruction(dbgs(), Inst, 0, &BF, true);
438 });
439 }
440 if (NoInfo)
441 break;
442 }
443 if (FunctionsRequireAlignment.count(V: &BF))
444 return UpdatedArgsTouched;
445
446 if (NoInfo) {
447 FunctionsRequireAlignment.insert(V: &BF);
448 return true;
449 }
450
451 for (BinaryBasicBlock &BB : BF) {
452 for (MCInst &Inst : BB) {
453 if (BC.MIB->requiresAlignedAddress(Inst)) {
454 FunctionsRequireAlignment.insert(V: &BF);
455 return true;
456 }
457 }
458 }
459 return UpdatedArgsTouched;
460}
461
462bool FrameAnalysis::restoreFrameIndex(BinaryFunction &BF) {
463 FrameAccessAnalysis FAA(BF, getSPT(BF));
464
465 LLVM_DEBUG(dbgs() << "Restoring frame indices for \"" << BF.getPrintName()
466 << "\"\n");
467 for (BinaryBasicBlock *BB : BF.getLayout().blocks()) {
468 LLVM_DEBUG(dbgs() << "\tNow at BB " << BB->getName() << "\n");
469 FAA.enterNewBB();
470
471 for (MCInst &Inst : *BB) {
472 if (!FAA.doNext(BB: *BB, Inst))
473 return false;
474 LLVM_DEBUG({
475 dbgs() << "\t\tNow at ";
476 Inst.dump();
477 dbgs() << "\t\t\tSP offset is " << FAA.getSPOffset() << "\n";
478 });
479
480 if (FAA.doesEscapeStackAddress()) {
481 if (!FunctionsWithStackArithmetic.count(V: &BF))
482 FunctionsWithStackArithmetic.insert(V: &BF);
483 continue;
484 }
485
486 if (!FAA.isValidAccess())
487 continue;
488
489 const FrameIndexEntry &FIE = FAA.getFIE();
490
491 addFIEFor(Inst, FIE);
492 LLVM_DEBUG({
493 dbgs() << "Frame index annotation " << FIE << " added to:\n";
494 BC.printInstruction(dbgs(), Inst, 0, &BF, true);
495 });
496 }
497 }
498 return true;
499}
500
501void FrameAnalysis::cleanAnnotations() {
502 NamedRegionTimer T("cleanannotations", "clean annotations", "FA",
503 "FA breakdown", opts::TimeFA);
504
505 ParallelUtilities::WorkFuncTy CleanFunction = [&](BinaryFunction &BF) {
506 for (BinaryBasicBlock &BB : BF) {
507 for (MCInst &Inst : BB) {
508 BC.MIB->removeAnnotation(Inst, Name: "ArgAccessEntry");
509 BC.MIB->removeAnnotation(Inst, Name: "FrameAccessEntry");
510 }
511 }
512 };
513
514 ParallelUtilities::runOnEachFunction(
515 BC, SchedPolicy: ParallelUtilities::SchedulingPolicy::SP_INST_LINEAR, WorkFunction: CleanFunction,
516 SkipPredicate: ParallelUtilities::PredicateTy(nullptr), LogName: "cleanAnnotations");
517}
518
519FrameAnalysis::FrameAnalysis(BinaryContext &BC, BinaryFunctionCallGraph &CG)
520 : BC(BC) {
521 // Position 0 of the vector should be always associated with "assume access
522 // everything".
523 ArgAccessesVector.emplace_back(args: ArgAccesses(/*AssumeEverything*/ true));
524
525 if (!opts::NoThreads) {
526 NamedRegionTimer T1("precomputespt", "pre-compute spt", "FA",
527 "FA breakdown", opts::TimeFA);
528 preComputeSPT();
529 }
530
531 {
532 NamedRegionTimer T1("traversecg", "traverse call graph", "FA",
533 "FA breakdown", opts::TimeFA);
534 traverseCG(CG);
535 }
536
537 for (auto &I : BC.getBinaryFunctions()) {
538 CountDenominator += I.second.getFunctionScore();
539
540 // "shouldOptimize" for passes that run after finalize
541 if (!(I.second.isSimple() && I.second.hasCFG() && !I.second.isIgnored()) ||
542 !opts::shouldFrameOptimize(Function: I.second)) {
543 ++NumFunctionsNotOptimized;
544 continue;
545 }
546
547 {
548 NamedRegionTimer T1("restorefi", "restore frame index", "FA",
549 "FA breakdown", opts::TimeFA);
550 if (!restoreFrameIndex(BF&: I.second)) {
551 ++NumFunctionsFailedRestoreFI;
552 CountFunctionsFailedRestoreFI += I.second.getFunctionScore();
553 continue;
554 }
555 }
556 AnalyzedFunctions.insert(V: &I.second);
557 }
558
559 {
560 NamedRegionTimer T1("clearspt", "clear spt", "FA", "FA breakdown",
561 opts::TimeFA);
562 clearSPTMap();
563 }
564}
565
566void FrameAnalysis::printStats() {
567 BC.outs() << "BOLT-INFO: FRAME ANALYSIS: " << NumFunctionsNotOptimized
568 << " function(s) were not optimized.\n"
569 << "BOLT-INFO: FRAME ANALYSIS: " << NumFunctionsFailedRestoreFI
570 << " function(s) "
571 << format(
572 Fmt: "(%.1lf%% dyn cov)",
573 Vals: (100.0 * CountFunctionsFailedRestoreFI / CountDenominator))
574 << " could not have its frame indices restored.\n";
575}
576
577void FrameAnalysis::clearSPTMap() {
578 if (opts::NoThreads) {
579 SPTMap.clear();
580 return;
581 }
582
583 ParallelUtilities::WorkFuncTy ClearFunctionSPT = [&](BinaryFunction &BF) {
584 std::unique_ptr<StackPointerTracking> &SPTPtr = SPTMap.find(x: &BF)->second;
585 SPTPtr.reset();
586 };
587
588 ParallelUtilities::PredicateTy SkipFunc = [&](const BinaryFunction &BF) {
589 return !BF.isSimple() || !BF.hasCFG();
590 };
591
592 ParallelUtilities::runOnEachFunction(
593 BC, SchedPolicy: ParallelUtilities::SchedulingPolicy::SP_INST_LINEAR, WorkFunction: ClearFunctionSPT,
594 SkipPredicate: SkipFunc, LogName: "clearSPTMap");
595
596 SPTMap.clear();
597}
598
599void FrameAnalysis::preComputeSPT() {
600 // Make sure that the SPTMap is empty
601 assert(SPTMap.size() == 0);
602
603 // Create map entries to allow lock-free parallel execution
604 for (auto &BFI : BC.getBinaryFunctions()) {
605 BinaryFunction &BF = BFI.second;
606 if (!BF.isSimple() || !BF.hasCFG())
607 continue;
608 SPTMap.emplace(args: &BF, args: std::unique_ptr<StackPointerTracking>());
609 }
610
611 // Create an index for the SPT annotation to allow lock-free parallel
612 // execution
613 BC.MIB->getOrCreateAnnotationIndex(Name: "StackPointerTracking");
614
615 // Run SPT in parallel
616 ParallelUtilities::WorkFuncWithAllocTy ProcessFunction =
617 [&](BinaryFunction &BF, MCPlusBuilder::AllocatorIdTy AllocId) {
618 std::unique_ptr<StackPointerTracking> &SPTPtr =
619 SPTMap.find(x: &BF)->second;
620 SPTPtr = std::make_unique<StackPointerTracking>(args&: BF, args&: AllocId);
621 SPTPtr->run();
622 };
623
624 ParallelUtilities::PredicateTy SkipPredicate = [&](const BinaryFunction &BF) {
625 return !BF.isSimple() || !BF.hasCFG();
626 };
627
628 ParallelUtilities::runOnEachFunctionWithUniqueAllocId(
629 BC, SchedPolicy: ParallelUtilities::SchedulingPolicy::SP_BB_QUADRATIC, WorkFunction: ProcessFunction,
630 SkipPredicate, LogName: "preComputeSPT");
631}
632
633} // namespace bolt
634} // namespace llvm
635

source code of bolt/lib/Passes/FrameAnalysis.cpp