cppcheck/lib/forwardanalyzer.cpp at main · codingman/cppcheck · GitHub

History

838 lines (786 loc) · 35.2 KB

Raw

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291

292

293

294

295

296

297

298

299

300

301

302

303

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

325

326

327

328

329

330

331

332

333

334

335

336

337

338

339

340

341

342

343

344

345

346

347

348

349

350

351

352

353

354

355

356

357

358

359

360

361

362

363

364

365

366

367

368

369

370

371

372

373

374

375

376

377

378

379

380

381

382

383

384

385

386

387

388

389

390

391

392

393

394

395

396

397

398

399

400

401

402

403

404

405

406

407

408

409

410

411

412

413

414

415

416

417

418

419

420

421

422

423

424

425

426

427

428

429

430

431

432

433

434

435

436

437

438

439

440

441

442

443

444

445

446

447

448

449

450

451

452

453

454

455

456

457

458

459

460

461

462

463

464

465

466

467

468

469

470

471

472

473

474

475

476

477

478

479

480

481

482

483

484

485

486

487

488

489

490

491

492

493

494

495

496

497

498

499

500

501

502

503

504

505

506

507

508

509

510

511

512

513

514

515

516

517

518

519

520

521

522

523

524

525

526

527

528

529

530

531

532

533

534

535

536

537

538

539

540

541

542

543

544

545

546

547

548

549

550

551

552

553

554

555

556

557

558

559

560

561

562

563

564

565

566

567

568

569

570

571

572

573

574

575

576

577

578

579

580

581

582

583

584

585

586

587

588

589

590

591

592

593

594

595

596

597

598

599

600

601

602

603

604

605

606

607

608

609

610

611

612

613

614

615

616

617

618

619

620

621

622

623

624

625

626

627

628

629

630

631

632

633

634

635

636

637

638

639

640

641

642

643

644

645

646

647

648

649

650

651

652

653

654

655

656

657

658

659

660

661

662

663

664

665

666

667

668

669

670

671

672

673

674

675

676

677

678

679

680

681

682

683

684

685

686

687

688

689

690

691

692

693

694

695

696

697

698

699

700

701

702

703

704

705

706

707

708

709

710

711

712

713

714

715

716

717

718

719

720

721

722

723

724

725

726

727

728

729

730

731

732

733

734

735

736

737

738

739

740

741

742

743

744

745

746

747

748

749

750

751

752

753

754

755

756

757

758

759

760

761

762

763

764

765

766

767

768

769

770

771

772

773

774

775

776

777

778

779

780

781

782

783

784

785

786

787

788

789

790

791

792

793

794

795

796

797

798

799

800

801

802

803

804

805

806

807

808

809

810

811

812

813

814

815

816

817

818

819

820

821

822

823

824

825

826

827

828

829

830

831

832

833

834

835

836

837

838

#include "forwardanalyzer.h"

#include "analyzer.h"

#include "astutils.h"

#include "settings.h"

#include "symboldatabase.h"

#include "token.h"

#include "valueptr.h"

#include <algorithm>

#include <cstdio>

#include <functional>

#include <tuple>

#include <utility>

struct OnExit {

std::function<void()> f;

~OnExit() {

f();

}

};

struct ForwardTraversal {

enum class Progress { Continue, Break, Skip };

enum class Terminate { None, Bail, Escape, Modified, Inconclusive, Conditional };

ForwardTraversal(const ValuePtr<Analyzer>& analyzer, const Settings* settings)

: analyzer(analyzer), settings(settings), actions(Analyzer::Action::None), analyzeOnly(false), analyzeTerminate(false)

{}

ValuePtr<Analyzer> analyzer;

const Settings* settings;

Analyzer::Action actions;

bool analyzeOnly;

bool analyzeTerminate;

Analyzer::Terminate terminate = Analyzer::Terminate::None;

bool forked = false;

std::vector<Token*> loopEnds = {};

Progress Break(Analyzer::Terminate t = Analyzer::Terminate::None) {

if ((!analyzeOnly || analyzeTerminate) && t != Analyzer::Terminate::None)

terminate = t;

return Progress::Break;

}

struct Branch {

Branch(Token* tok = nullptr) : endBlock(tok) {}

Token* endBlock = nullptr;

Analyzer::Action action = Analyzer::Action::None;

bool check = false;

bool escape = false;

bool escapeUnknown = false;

bool active = false;

bool isEscape() const {

return escape || escapeUnknown;

}

bool isConclusiveEscape() const {

return escape && !escapeUnknown;

}

bool isModified() const {

return action.isModified() && !isConclusiveEscape();

}

bool isInconclusive() const {

return action.isInconclusive() && !isConclusiveEscape();

}

bool isDead() const {

return action.isModified() || action.isInconclusive() || isEscape();

}

};

bool stopUpdates() {

analyzeOnly = true;

return actions.isModified();

}

std::pair<bool, bool> evalCond(const Token* tok, const Token* ctx = nullptr) const {

if (!tok)

return std::make_pair(false, false);

std::vector<MathLib::bigint> result = analyzer->evaluate(tok, ctx);

// TODO: We should convert to bool

bool checkThen = std::any_of(result.begin(), result.end(), [](int x) {

return x != 0;

});

bool checkElse = std::any_of(result.begin(), result.end(), [](int x) {

return x == 0;

});

return std::make_pair(checkThen, checkElse);

}

bool isConditionTrue(const Token* tok, const Token* ctx = nullptr) const {

return evalCond(tok, ctx).first;

}

bool isConditionFalse(const Token* tok, const Token* ctx = nullptr) const {

return evalCond(tok, ctx).second;

}

template<class T, REQUIRES("T must be a Token class", std::is_convertible<T*, const Token*> )>

Progress traverseTok(T* tok, std::function<Progress(T*)> f, bool traverseUnknown, T** out = nullptr) {

if (Token::Match(tok, "asm|goto|setjmp|longjmp"))

return Break(Analyzer::Terminate::Bail);

else if (Token::simpleMatch(tok, "continue")) {

if (loopEnds.empty())

return Break(Analyzer::Terminate::Escape);

// If we are in a loop then jump to the end

if (out)

*out = loopEnds.back();

} else if (Token::Match(tok, "return|throw") || isEscapeFunction(tok, &settings->library)) {

traverseRecursive(tok->astOperand1(), f, traverseUnknown);

traverseRecursive(tok->astOperand2(), f, traverseUnknown);

return Break(Analyzer::Terminate::Escape);

} else if (isUnevaluated(tok)) {

if (out)

*out = tok->link();

return Progress::Skip;

} else if (tok->astOperand1() && tok->astOperand2() && Token::Match(tok, "?|&&|%oror%")) {

if (traverseConditional(tok, f, traverseUnknown) == Progress::Break)

return Break();

if (out)

*out = nextAfterAstRightmostLeaf(tok);

return Progress::Skip;

// Skip lambdas

} else if (T* lambdaEndToken = findLambdaEndToken(tok)) {

if (checkScope(lambdaEndToken).isModified())

return Break(Analyzer::Terminate::Bail);

if (out)

*out = lambdaEndToken->next();

// Skip class scope

} else if (tok->str() == "{" && tok->scope() && tok->scope()->isClassOrStruct()) {

if (out)

*out = tok->link();

} else {

if (f(tok) == Progress::Break)

return Break();

}

return Progress::Continue;

}

template<class T, REQUIRES("T must be a Token class", std::is_convertible<T*, const Token*> )>

Progress traverseRecursive(T* tok, std::function<Progress(T*)> f, bool traverseUnknown, unsigned int recursion=0) {

if (!tok)

return Progress::Continue;

if (recursion > 10000)

return Progress::Skip;

T* firstOp = tok->astOperand1();

T* secondOp = tok->astOperand2();

// Evaluate:

// 1. RHS of assignment before LHS

// 2. Unary op before operand

if (tok->isAssignmentOp() || !secondOp)

std::swap(firstOp, secondOp);

if (firstOp && traverseRecursive(firstOp, f, traverseUnknown, recursion+1) == Progress::Break)

return Break();

Progress p = tok->isAssignmentOp() ? Progress::Continue : traverseTok(tok, f, traverseUnknown);

if (p == Progress::Break)

return Break();

if (p == Progress::Continue && secondOp && traverseRecursive(secondOp, f, traverseUnknown, recursion+1) == Progress::Break)

return Break();

if (tok->isAssignmentOp() && traverseTok(tok, f, traverseUnknown) == Progress::Break)

return Break();

return Progress::Continue;

}

template<class T, class F, REQUIRES("T must be a Token class", std::is_convertible<T*, const Token*> )>

Progress traverseConditional(T* tok, F f, bool traverseUnknown) {

if (Token::Match(tok, "?|&&|%oror%") && tok->astOperand1() && tok->astOperand2()) {

T* condTok = tok->astOperand1();

T* childTok = tok->astOperand2();

bool checkThen, checkElse;

std::tie(checkThen, checkElse) = evalCond(condTok);

if (!checkThen && !checkElse) {

if (!traverseUnknown && analyzer->stopOnCondition(condTok) && stopUpdates()) {

return Progress::Continue;

}

checkThen = true;

checkElse = true;

}

if (childTok->str() == ":") {

if (checkThen && traverseRecursive(childTok->astOperand1(), f, traverseUnknown) == Progress::Break)

return Break();

if (checkElse && traverseRecursive(childTok->astOperand2(), f, traverseUnknown) == Progress::Break)

return Break();

} else {

if (!checkThen && tok->str() == "&&")

return Progress::Continue;

if (!checkElse && tok->str() == "||")

return Progress::Continue;

if (traverseRecursive(childTok, f, traverseUnknown) == Progress::Break)

return Break();

}

return Progress::Continue;

}

Progress update(Token* tok) {

Analyzer::Action action = analyzer->analyze(tok, Analyzer::Direction::Forward);

actions |= action;

if (!action.isNone() && !analyzeOnly)

analyzer->update(tok, action, Analyzer::Direction::Forward);

if (action.isInconclusive() && !analyzer->lowerToInconclusive())

return Break(Analyzer::Terminate::Inconclusive);

if (action.isInvalid())

return Break(Analyzer::Terminate::Modified);

if (action.isWrite() && !action.isRead())

// Analysis of this write will continue separately

return Break(Analyzer::Terminate::Modified);

return Progress::Continue;

}

Progress updateTok(Token* tok, Token** out = nullptr) {

std::function<Progress(Token*)> f = [this](Token* tok2) {

return update(tok2);

};

return traverseTok(tok, f, false, out);

}

Progress updateRecursive(Token* tok) {

forked = false;

std::function<Progress(Token*)> f = [this](Token* tok2) {

return update(tok2);

};

return traverseRecursive(tok, f, false);

}

template<class T>

T* findRange(T* start, const Token* end, std::function<bool(Analyzer::Action)> pred) {

for (T* tok = start; tok && tok != end; tok = tok->next()) {

Analyzer::Action action = analyzer->analyze(tok, Analyzer::Direction::Forward);

if (pred(action))

return tok;

}

return nullptr;

}

Analyzer::Action analyzeRecursive(const Token* start) {

Analyzer::Action result = Analyzer::Action::None;

std::function<Progress(const Token*)> f = [&](const Token* tok) {

result = analyzer->analyze(tok, Analyzer::Direction::Forward);

if (result.isModified() || result.isInconclusive())

return Break();

return Progress::Continue;

};

traverseRecursive(start, f, true);

return result;

}

Analyzer::Action analyzeRange(const Token* start, const Token* end) {

Analyzer::Action result = Analyzer::Action::None;

for (const Token* tok = start; tok && tok != end; tok = tok->next()) {

Analyzer::Action action = analyzer->analyze(tok, Analyzer::Direction::Forward);

if (action.isModified() || action.isInconclusive())

return action;

result |= action;

}

return result;

}

ForwardTraversal fork(bool analyze = false) const {

ForwardTraversal ft = *this;

if (analyze) {

ft.analyzeOnly = true;

ft.analyzeTerminate = true;

}

ft.actions = Analyzer::Action::None;

ft.forked = true;

return ft;

}

std::vector<ForwardTraversal> tryForkScope(Token* endBlock, bool isModified = false) {

if (analyzer->updateScope(endBlock, isModified)) {

ForwardTraversal ft = fork();

return {ft};

}

return std::vector<ForwardTraversal> {};

}

std::vector<ForwardTraversal> tryForkUpdateScope(Token* endBlock, bool isModified = false) {

std::vector<ForwardTraversal> result = tryForkScope(endBlock, isModified);

for (ForwardTraversal& ft : result)

ft.updateScope(endBlock);

return result;

}

static bool hasGoto(const Token* endBlock) {

return Token::findsimplematch(endBlock->link(), "goto", endBlock);

}

bool hasInnerReturnScope(const Token* start, const Token* end) const {

for (const Token* tok=start; tok != end; tok = tok->previous()) {

if (Token::simpleMatch(tok, "}")) {

const Token* ftok = nullptr;

bool r = isReturnScope(tok, &settings->library, &ftok);

if (r)

return true;

}

return false;

}

bool isEscapeScope(const Token* endBlock, bool& unknown) {

const Token* ftok = nullptr;

bool r = isReturnScope(endBlock, &settings->library, &ftok);

if (!r && ftok)

unknown = true;

return r;

}

enum class Status {

None,

Escaped,

Modified,

Inconclusive,

};

Analyzer::Action analyzeScope(const Token* endBlock) {

return analyzeRange(endBlock->link(), endBlock);

}

Analyzer::Action checkScope(Token* endBlock) {

Analyzer::Action a = analyzeScope(endBlock);

tryForkUpdateScope(endBlock, a.isModified());

return a;

}

Analyzer::Action checkScope(const Token* endBlock) {

Analyzer::Action a = analyzeScope(endBlock);

return a;

}

bool checkBranch(Branch& branch) {

Analyzer::Action a = analyzeScope(branch.endBlock);

branch.action = a;

std::vector<ForwardTraversal> ft1 = tryForkUpdateScope(branch.endBlock, a.isModified());

bool bail = hasGoto(branch.endBlock);

if (!a.isModified() && !bail) {

if (ft1.empty()) {

// Traverse into the branch to see if there is a conditional escape

if (!branch.escape && hasInnerReturnScope(branch.endBlock->previous(), branch.endBlock->link())) {

ForwardTraversal ft2 = fork(true);

ft2.updateScope(branch.endBlock);

if (ft2.terminate == Analyzer::Terminate::Escape) {

branch.escape = true;

branch.escapeUnknown = false;

}

} else {

if (ft1.front().terminate == Analyzer::Terminate::Escape) {

branch.escape = true;

branch.escapeUnknown = false;

}

return bail;

}

bool reentersLoop(Token* endBlock, const Token* condTok, const Token* stepTok) {

if (!condTok)

return true;

if (Token::simpleMatch(condTok, ":"))

return true;

bool changed = false;

if (stepTok) {

std::pair<const Token*, const Token*> exprToks = stepTok->findExpressionStartEndTokens();

if (exprToks.first != nullptr && exprToks.second != nullptr)

changed |= isExpressionChanged(condTok, exprToks.first, exprToks.second->next(), settings, true);

}

changed |= isExpressionChanged(condTok, endBlock->link(), endBlock, settings, true);

// Check for mutation in the condition

changed |= nullptr !=

findAstNode(condTok, [&](const Token* tok) {

return isVariableChanged(tok, 0, settings, true);

});

if (!changed)

return true;

ForwardTraversal ft = fork(true);

ft.analyzer->assume(condTok, false, Analyzer::Assume::Absolute);

ft.updateScope(endBlock);

return ft.isConditionTrue(condTok);

}

Progress updateInnerLoop(Token* endBlock, Token* stepTok, Token* condTok) {

loopEnds.push_back(endBlock);

OnExit oe{[&] {

loopEnds.pop_back();

}};

if (endBlock && updateScope(endBlock) == Progress::Break)

return Break();

if (stepTok && updateRecursive(stepTok) == Progress::Break)

return Break();

if (condTok && updateRecursive(condTok) == Progress::Break)

return Break();

return Progress::Continue;

}

Progress updateLoop(const Token* endToken,

Token* endBlock,

Token* condTok,

Token* initTok = nullptr,

Token* stepTok = nullptr,

bool exit = false) {

if (initTok && updateRecursive(initTok) == Progress::Break)

return Break();

const bool isDoWhile = precedes(endBlock, condTok);

bool checkThen = true;

bool checkElse = false;

if (condTok && !Token::simpleMatch(condTok, ":"))

std::tie(checkThen, checkElse) = evalCond(condTok, isDoWhile ? endBlock->previous() : nullptr);

if (checkElse && exit)

return Progress::Continue;

Analyzer::Action bodyAnalysis = analyzeScope(endBlock);

Analyzer::Action allAnalysis = bodyAnalysis;

Analyzer::Action condAnalysis;

if (condTok) {

condAnalysis = analyzeRecursive(condTok);

allAnalysis |= condAnalysis;

}

if (stepTok)

allAnalysis |= analyzeRecursive(stepTok);

actions |= allAnalysis;

// do while(false) is not really a loop

if (checkElse && isDoWhile &&

(condTok->hasKnownIntValue() ||

(!bodyAnalysis.isModified() && !condAnalysis.isModified() && condAnalysis.isRead()))) {

if (updateRange(endBlock->link(), endBlock) == Progress::Break)

return Break();

return updateRecursive(condTok);

}

if (allAnalysis.isInconclusive()) {

if (!analyzer->lowerToInconclusive())

return Break(Analyzer::Terminate::Bail);

} else if (allAnalysis.isModified() || (exit && allAnalysis.isIdempotent())) {

if (!analyzer->lowerToPossible())

return Break(Analyzer::Terminate::Bail);

}

if (condTok && !Token::simpleMatch(condTok, ":")) {

if (!isDoWhile || (!bodyAnalysis.isModified() && !bodyAnalysis.isIdempotent()))

if (updateRecursive(condTok) == Progress::Break)

return Break();

}

if (!checkThen && !checkElse && !isDoWhile && analyzer->stopOnCondition(condTok) && stopUpdates())

return Break(Analyzer::Terminate::Conditional);

// condition is false, we don't enter the loop

if (checkElse)

return Progress::Continue;

if (checkThen || isDoWhile) {

// Since we are re-entering the loop then assume the condition is true to update the state

if (exit)

analyzer->assume(condTok, true, Analyzer::Assume::Quiet | Analyzer::Assume::Absolute);

if (updateInnerLoop(endBlock, stepTok, condTok) == Progress::Break)

return Break();

// If loop re-enters then it could be modified again

if (allAnalysis.isModified() && reentersLoop(endBlock, condTok, stepTok))

return Break(Analyzer::Terminate::Bail);

if (allAnalysis.isIncremental())

return Break(Analyzer::Terminate::Bail);

} else if (allAnalysis.isModified()) {

std::vector<ForwardTraversal> ftv = tryForkScope(endBlock, allAnalysis.isModified());

bool forkContinue = true;

for (ForwardTraversal& ft : ftv) {

if (condTok)

ft.analyzer->assume(condTok, false, Analyzer::Assume::Quiet);

if (ft.updateInnerLoop(endBlock, stepTok, condTok) == Progress::Break)

forkContinue = false;

}

if (allAnalysis.isModified() || !forkContinue) {

// TODO: Don't bail on missing condition

if (!condTok)

return Break(Analyzer::Terminate::Bail);

if (analyzer->isConditional() && stopUpdates())

return Break(Analyzer::Terminate::Conditional);

analyzer->assume(condTok, false);

}

if (forkContinue) {

for (ForwardTraversal& ft : ftv) {

if (!ft.actions.isIncremental())

ft.updateRange(endBlock, endToken);

}

if (allAnalysis.isIncremental())

return Break(Analyzer::Terminate::Bail);

} else {

if (updateInnerLoop(endBlock, stepTok, condTok) == Progress::Break)

return Progress::Break;

if (allAnalysis.isIncremental())

return Break(Analyzer::Terminate::Bail);

}

return Progress::Continue;

}

Progress updateLoopExit(const Token* endToken,

Token* endBlock,

Token* condTok,

Token* initTok = nullptr,

Token* stepTok = nullptr) {

return updateLoop(endToken, endBlock, condTok, initTok, stepTok, true);

}

Progress updateScope(Token* endBlock) {

if (forked)

analyzer->forkScope(endBlock);

return updateRange(endBlock->link(), endBlock);

}

Progress updateRange(Token* start, const Token* end, int depth = 20) {

forked = false;

if (depth < 0)

return Break(Analyzer::Terminate::Bail);

std::size_t i = 0;

for (Token* tok = start; precedes(tok, end); tok = tok->next()) {

Token* next = nullptr;

if (tok->index() <= i)

throw InternalError(tok, "Cyclic forward analysis.");

i = tok->index();

if (tok->link()) {

// Skip casts..

if (tok->str() == "(" && !tok->astOperand2() && tok->isCast()) {

tok = tok->link();

continue;

}

// Skip template arguments..

if (tok->str() == "<") {

tok = tok->link();

continue;

}

// Evaluate RHS of assignment before LHS

if (Token* assignTok = assignExpr(tok)) {

if (updateRecursive(assignTok) == Progress::Break)

return Break();

tok = nextAfterAstRightmostLeaf(assignTok);

if (!tok)

return Break();

} else if (tok->str() == "break") {

const Token *scopeEndToken = findNextTokenFromBreak(tok);

if (!scopeEndToken)

return Break();

tok = skipTo(tok, scopeEndToken, end);

if (!analyzer->lowerToPossible())

return Break(Analyzer::Terminate::Bail);

// TODO: Don't break, instead move to the outer scope

if (!tok)

return Break();

} else if (Token::Match(tok, "%name% :") || tok->str() == "case") {

if (!analyzer->lowerToPossible())

return Break(Analyzer::Terminate::Bail);

} else if (tok->link() && tok->str() == "}") {

const Scope* scope = tok->scope();

if (!scope)

return Break();

if (Token::Match(tok->link()->previous(), ")|else {")) {

const Token* tok2 = tok->link()->previous();

const bool inElse = Token::simpleMatch(tok2, "else {");

const bool inLoop = inElse ? false : Token::Match(tok2->link()->previous(), "while|for (");

Token* condTok = getCondTokFromEnd(tok);

if (!condTok)

return Break();

if (!condTok->hasKnownIntValue() || inLoop) {

if (!analyzer->lowerToPossible())

return Break(Analyzer::Terminate::Bail);

} else if (condTok->values().front().intvalue == inElse) {

return Break();

}

// Handle for loop

Token* stepTok = getStepTokFromEnd(tok);

bool checkThen, checkElse;

std::tie(checkThen, checkElse) = evalCond(condTok);

if (stepTok && !checkElse) {

if (updateRecursive(stepTok) == Progress::Break)

return Break();

if (updateRecursive(condTok) == Progress::Break)

return Break();

}

analyzer->assume(condTok, !inElse, Analyzer::Assume::Quiet);

if (Token::simpleMatch(tok, "} else {"))

tok = tok->linkAt(2);

} else if (scope->type == Scope::eTry) {

if (!analyzer->lowerToPossible())

return Break(Analyzer::Terminate::Bail);

} else if (scope->type == Scope::eLambda) {

return Break();

} else if (scope->type == Scope::eDo && Token::simpleMatch(tok, "} while (")) {

if (updateLoopExit(end, tok, tok->tokAt(2)->astOperand2()) == Progress::Break)

return Break();

tok = tok->linkAt(2);

} else if (Token::simpleMatch(tok->next(), "else {")) {

tok = tok->linkAt(2);

}

} else if (tok->isControlFlowKeyword() && Token::Match(tok, "if|while|for (") && Token::simpleMatch(tok->next()->link(), ") {")) {

Token* endCond = tok->next()->link();

Token* endBlock = endCond->next()->link();

Token* condTok = getCondTok(tok);

Token* initTok = getInitTok(tok);

if (initTok && updateRecursive(initTok) == Progress::Break)

return Break();

if (Token::Match(tok, "for|while (")) {

// For-range loop

if (Token::simpleMatch(condTok, ":")) {

Token* conTok = condTok->astOperand2();

if (conTok && updateRecursive(conTok) == Progress::Break)

return Break();

bool isEmpty = false;

std::vector<MathLib::bigint> result =

analyzer->evaluate(Analyzer::Evaluate::ContainerEmpty, conTok);

if (result.empty())

analyzer->assume(conTok, false, Analyzer::Assume::ContainerEmpty);

else

isEmpty = result.front() != 0;

if (!isEmpty && updateLoop(end, endBlock, condTok) == Progress::Break)

return Break();

} else {

Token* stepTok = getStepTok(tok);

if (updateLoop(end, endBlock, condTok, initTok, stepTok) == Progress::Break)

return Break();

}

tok = endBlock;

} else {

// Traverse condition

if (updateRecursive(condTok) == Progress::Break)

return Break();

Branch thenBranch{endBlock};

Branch elseBranch{endBlock->tokAt(2) ? endBlock->linkAt(2) : nullptr};

// Check if condition is true or false

std::tie(thenBranch.check, elseBranch.check) = evalCond(condTok);

if (!thenBranch.check && !elseBranch.check && analyzer->stopOnCondition(condTok) && stopUpdates())

return Break(Analyzer::Terminate::Conditional);

bool hasElse = Token::simpleMatch(endBlock, "} else {");

bool bail = false;

// Traverse then block

thenBranch.escape = isEscapeScope(endBlock, thenBranch.escapeUnknown);

if (thenBranch.check) {

thenBranch.active = true;

if (updateRange(endCond->next(), endBlock, depth - 1) == Progress::Break)

return Break();

} else if (!elseBranch.check) {

thenBranch.active = true;

if (checkBranch(thenBranch))

bail = true;

}

// Traverse else block

if (hasElse) {

elseBranch.escape = isEscapeScope(endBlock->linkAt(2), elseBranch.escapeUnknown);

if (elseBranch.check) {

elseBranch.active = true;

Progress result = updateRange(endBlock->tokAt(2), endBlock->linkAt(2), depth - 1);

if (result == Progress::Break)

return Break();

} else if (!thenBranch.check) {

elseBranch.active = true;

if (checkBranch(elseBranch))

bail = true;

}

tok = endBlock->linkAt(2);

} else {

tok = endBlock;

}

if (thenBranch.active)

actions |= thenBranch.action;

if (elseBranch.active)

actions |= elseBranch.action;

if (bail)

return Break(Analyzer::Terminate::Bail);

if (thenBranch.isDead() && elseBranch.isDead()) {

if (thenBranch.isModified() && elseBranch.isModified())

return Break(Analyzer::Terminate::Modified);

if (thenBranch.isConclusiveEscape() && elseBranch.isConclusiveEscape())

return Break(Analyzer::Terminate::Escape);

return Break(Analyzer::Terminate::Bail);

}

// Conditional return

if (thenBranch.active && thenBranch.isEscape() && !hasElse) {

if (!thenBranch.isConclusiveEscape()) {

if (!analyzer->lowerToInconclusive())

return Break(Analyzer::Terminate::Bail);

} else if (thenBranch.check) {

return Break();

} else {

if (analyzer->isConditional() && stopUpdates())

return Break(Analyzer::Terminate::Conditional);

analyzer->assume(condTok, false);

}

if (thenBranch.isInconclusive() || elseBranch.isInconclusive()) {

if (!analyzer->lowerToInconclusive())

return Break(Analyzer::Terminate::Bail);

} else if (thenBranch.isModified() || elseBranch.isModified()) {

if (!hasElse && analyzer->isConditional() && stopUpdates())

return Break(Analyzer::Terminate::Conditional);

if (!analyzer->lowerToPossible())

return Break(Analyzer::Terminate::Bail);

analyzer->assume(condTok, elseBranch.isModified());

}

} else if (Token::simpleMatch(tok, "try {")) {

Token* endBlock = tok->next()->link();

ForwardTraversal tryTraversal = fork();

tryTraversal.updateRange(tok->next(), endBlock, depth - 1);

bool bail = tryTraversal.actions.isModified();

if (bail)

analyzer->lowerToPossible();

while (Token::simpleMatch(endBlock, "} catch (")) {

Token* endCatch = endBlock->linkAt(2);

if (!Token::simpleMatch(endCatch, ") {"))

return Break();

endBlock = endCatch->linkAt(1);

ForwardTraversal ft = fork();

ft.updateRange(endBlock->link(), endBlock, depth - 1);

bail |= ft.terminate != Analyzer::Terminate::None || ft.actions.isModified();

}

if (bail)

return Break();

tok = endBlock;

} else if (Token::simpleMatch(tok, "do {")) {

Token* endBlock = tok->next()->link();

Token* condTok = Token::simpleMatch(endBlock, "} while (") ? endBlock->tokAt(2)->astOperand2() : nullptr;

if (updateLoop(end, endBlock, condTok) == Progress::Break)

return Break();

if (condTok)

tok = endBlock->linkAt(2)->next();

else

tok = endBlock;

} else if (Token::Match(tok, "assert|ASSERT (")) {

const Token* condTok = tok->next()->astOperand2();

bool checkThen, checkElse;

std::tie(checkThen, checkElse) = evalCond(condTok);

if (checkElse)

return Break();

if (!checkThen)

analyzer->assume(condTok, true, Analyzer::Assume::Quiet | Analyzer::Assume::Absolute);

} else if (Token::simpleMatch(tok, "switch (")) {

if (updateRecursive(tok->next()->astOperand2()) == Progress::Break)

return Break();

} else {

if (updateTok(tok, &next) == Progress::Break)

return Break();

if (next) {

if (precedes(next, end))

tok = next->previous();

else

return Break();

}

// Prevent infinite recursion

if (tok->next() == start)

break;

}

return Progress::Continue;

}

static bool isUnevaluated(const Token* tok) {

if (Token::Match(tok->previous(), "sizeof|decltype ("))

return true;

return false;

}

static Token* assignExpr(Token* tok) {

while (tok->astParent() && astIsLHS(tok)) {

if (tok->astParent()->isAssignmentOp())

return tok->astParent();

tok = tok->astParent();

}

return nullptr;

}

static Token* skipTo(Token* tok, const Token* dest, const Token* end = nullptr) {

if (end && dest->index() > end->index())

return nullptr;

int i = dest->index() - tok->index();

if (i > 0)

return tok->tokAt(dest->index() - tok->index());

return nullptr;

}

static bool isConditional(const Token* tok) {

const Token* parent = tok->astParent();

while (parent && !Token::Match(parent, "%oror%|&&|:")) {

tok = parent;

parent = parent->astParent();

}

return parent && (parent->str() == ":" || parent->astOperand2() == tok);

}

static Token* getInitTok(Token* tok) {

if (!tok)

return nullptr;

if (Token::Match(tok, "%name% ("))

return getInitTok(tok->next());

if (tok->str() != "(")

return nullptr;

if (!Token::simpleMatch(tok->astOperand2(), ";"))

return nullptr;

if (Token::simpleMatch(tok->astOperand2()->astOperand1(), ";"))

return nullptr;

return tok->astOperand2()->astOperand1();

}

static Token* getStepTok(Token* tok) {

if (!tok)

return nullptr;

if (Token::Match(tok, "%name% ("))

return getStepTok(tok->next());

if (tok->str() != "(")

return nullptr;

if (!Token::simpleMatch(tok->astOperand2(), ";"))

return nullptr;

if (!Token::simpleMatch(tok->astOperand2()->astOperand2(), ";"))

return nullptr;

return tok->astOperand2()->astOperand2()->astOperand2();

}

static Token* getStepTokFromEnd(Token* tok) {

if (!Token::simpleMatch(tok, "}"))

return nullptr;

Token* end = tok->link()->previous();

if (!Token::simpleMatch(end, ")"))

return nullptr;

return getStepTok(end->link());

}

};

Analyzer::Result valueFlowGenericForward(Token* start, const Token* end, const ValuePtr<Analyzer>& a, const Settings* settings)

{

ForwardTraversal ft{a, settings};

ft.updateRange(start, end);

return {ft.actions, ft.terminate};

}

Analyzer::Result valueFlowGenericForward(Token* start, const ValuePtr<Analyzer>& a, const Settings* settings)

{

ForwardTraversal ft{a, settings};

ft.updateRecursive(start);

return {ft.actions, ft.terminate};

}

cppcheck/lib/forwardanalyzer.cpp at main · codingman/cppcheck · GitHub

Expand file tree

Breadcrumbs

forwardanalyzer.cpp

Latest commit

History

Breadcrumbs

forwardanalyzer.cpp

File metadata and controls