clang  17.0.0git
UninitializedValues.cpp
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1 //===- UninitializedValues.cpp - Find Uninitialized Values ----------------===//
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 uninitialized values analysis for source-level CFGs.
10 //
11 //===----------------------------------------------------------------------===//
12 
14 #include "clang/AST/Attr.h"
15 #include "clang/AST/Decl.h"
16 #include "clang/AST/DeclBase.h"
17 #include "clang/AST/Expr.h"
19 #include "clang/AST/Stmt.h"
20 #include "clang/AST/StmtObjC.h"
21 #include "clang/AST/StmtVisitor.h"
22 #include "clang/AST/Type.h"
25 #include "clang/Analysis/CFG.h"
28 #include "clang/Basic/LLVM.h"
29 #include "llvm/ADT/BitVector.h"
30 #include "llvm/ADT/DenseMap.h"
31 #include "llvm/ADT/PackedVector.h"
32 #include "llvm/ADT/SmallBitVector.h"
33 #include "llvm/ADT/SmallVector.h"
34 #include "llvm/Support/Casting.h"
35 #include <algorithm>
36 #include <cassert>
37 #include <optional>
38 
39 using namespace clang;
40 
41 #define DEBUG_LOGGING 0
42 
43 static bool isTrackedVar(const VarDecl *vd, const DeclContext *dc) {
44  if (vd->isLocalVarDecl() && !vd->hasGlobalStorage() &&
45  !vd->isExceptionVariable() && !vd->isInitCapture() &&
46  !vd->isImplicit() && vd->getDeclContext() == dc) {
47  QualType ty = vd->getType();
48  return ty->isScalarType() || ty->isVectorType() || ty->isRecordType() ||
49  ty->isRVVType();
50  }
51  return false;
52 }
53 
54 //------------------------------------------------------------------------====//
55 // DeclToIndex: a mapping from Decls we track to value indices.
56 //====------------------------------------------------------------------------//
57 
58 namespace {
59 
60 class DeclToIndex {
61  llvm::DenseMap<const VarDecl *, unsigned> map;
62 
63 public:
64  DeclToIndex() = default;
65 
66  /// Compute the actual mapping from declarations to bits.
67  void computeMap(const DeclContext &dc);
68 
69  /// Return the number of declarations in the map.
70  unsigned size() const { return map.size(); }
71 
72  /// Returns the bit vector index for a given declaration.
73  std::optional<unsigned> getValueIndex(const VarDecl *d) const;
74 };
75 
76 } // namespace
77 
78 void DeclToIndex::computeMap(const DeclContext &dc) {
79  unsigned count = 0;
81  E(dc.decls_end());
82  for ( ; I != E; ++I) {
83  const VarDecl *vd = *I;
84  if (isTrackedVar(vd, &dc))
85  map[vd] = count++;
86  }
87 }
88 
89 std::optional<unsigned> DeclToIndex::getValueIndex(const VarDecl *d) const {
90  llvm::DenseMap<const VarDecl *, unsigned>::const_iterator I = map.find(d);
91  if (I == map.end())
92  return std::nullopt;
93  return I->second;
94 }
95 
96 //------------------------------------------------------------------------====//
97 // CFGBlockValues: dataflow values for CFG blocks.
98 //====------------------------------------------------------------------------//
99 
100 // These values are defined in such a way that a merge can be done using
101 // a bitwise OR.
102 enum Value { Unknown = 0x0, /* 00 */
103  Initialized = 0x1, /* 01 */
104  Uninitialized = 0x2, /* 10 */
105  MayUninitialized = 0x3 /* 11 */ };
106 
107 static bool isUninitialized(const Value v) {
108  return v >= Uninitialized;
109 }
110 
111 static bool isAlwaysUninit(const Value v) {
112  return v == Uninitialized;
113 }
114 
115 namespace {
116 
117 using ValueVector = llvm::PackedVector<Value, 2, llvm::SmallBitVector>;
118 
119 class CFGBlockValues {
120  const CFG &cfg;
122  ValueVector scratch;
123  DeclToIndex declToIndex;
124 
125 public:
126  CFGBlockValues(const CFG &cfg);
127 
128  unsigned getNumEntries() const { return declToIndex.size(); }
129 
130  void computeSetOfDeclarations(const DeclContext &dc);
131 
132  ValueVector &getValueVector(const CFGBlock *block) {
133  return vals[block->getBlockID()];
134  }
135 
136  void setAllScratchValues(Value V);
137  void mergeIntoScratch(ValueVector const &source, bool isFirst);
138  bool updateValueVectorWithScratch(const CFGBlock *block);
139 
140  bool hasNoDeclarations() const {
141  return declToIndex.size() == 0;
142  }
143 
144  void resetScratch();
145 
146  ValueVector::reference operator[](const VarDecl *vd);
147 
148  Value getValue(const CFGBlock *block, const CFGBlock *dstBlock,
149  const VarDecl *vd) {
150  std::optional<unsigned> idx = declToIndex.getValueIndex(vd);
151  return getValueVector(block)[*idx];
152  }
153 };
154 
155 } // namespace
156 
157 CFGBlockValues::CFGBlockValues(const CFG &c) : cfg(c), vals(0) {}
158 
159 void CFGBlockValues::computeSetOfDeclarations(const DeclContext &dc) {
160  declToIndex.computeMap(dc);
161  unsigned decls = declToIndex.size();
162  scratch.resize(decls);
163  unsigned n = cfg.getNumBlockIDs();
164  if (!n)
165  return;
166  vals.resize(n);
167  for (auto &val : vals)
168  val.resize(decls);
169 }
170 
171 #if DEBUG_LOGGING
172 static void printVector(const CFGBlock *block, ValueVector &bv,
173  unsigned num) {
174  llvm::errs() << block->getBlockID() << " :";
175  for (const auto &i : bv)
176  llvm::errs() << ' ' << i;
177  llvm::errs() << " : " << num << '\n';
178 }
179 #endif
180 
181 void CFGBlockValues::setAllScratchValues(Value V) {
182  for (unsigned I = 0, E = scratch.size(); I != E; ++I)
183  scratch[I] = V;
184 }
185 
186 void CFGBlockValues::mergeIntoScratch(ValueVector const &source,
187  bool isFirst) {
188  if (isFirst)
189  scratch = source;
190  else
191  scratch |= source;
192 }
193 
194 bool CFGBlockValues::updateValueVectorWithScratch(const CFGBlock *block) {
195  ValueVector &dst = getValueVector(block);
196  bool changed = (dst != scratch);
197  if (changed)
198  dst = scratch;
199 #if DEBUG_LOGGING
200  printVector(block, scratch, 0);
201 #endif
202  return changed;
203 }
204 
205 void CFGBlockValues::resetScratch() {
206  scratch.reset();
207 }
208 
209 ValueVector::reference CFGBlockValues::operator[](const VarDecl *vd) {
210  return scratch[*declToIndex.getValueIndex(vd)];
211 }
212 
213 //------------------------------------------------------------------------====//
214 // Classification of DeclRefExprs as use or initialization.
215 //====------------------------------------------------------------------------//
216 
217 namespace {
218 
219 class FindVarResult {
220  const VarDecl *vd;
221  const DeclRefExpr *dr;
222 
223 public:
224  FindVarResult(const VarDecl *vd, const DeclRefExpr *dr) : vd(vd), dr(dr) {}
225 
226  const DeclRefExpr *getDeclRefExpr() const { return dr; }
227  const VarDecl *getDecl() const { return vd; }
228 };
229 
230 } // namespace
231 
232 static const Expr *stripCasts(ASTContext &C, const Expr *Ex) {
233  while (Ex) {
234  Ex = Ex->IgnoreParenNoopCasts(C);
235  if (const auto *CE = dyn_cast<CastExpr>(Ex)) {
236  if (CE->getCastKind() == CK_LValueBitCast) {
237  Ex = CE->getSubExpr();
238  continue;
239  }
240  }
241  break;
242  }
243  return Ex;
244 }
245 
246 /// If E is an expression comprising a reference to a single variable, find that
247 /// variable.
248 static FindVarResult findVar(const Expr *E, const DeclContext *DC) {
249  if (const auto *DRE =
250  dyn_cast<DeclRefExpr>(stripCasts(DC->getParentASTContext(), E)))
251  if (const auto *VD = dyn_cast<VarDecl>(DRE->getDecl()))
252  if (isTrackedVar(VD, DC))
253  return FindVarResult(VD, DRE);
254  return FindVarResult(nullptr, nullptr);
255 }
256 
257 namespace {
258 
259 /// Classify each DeclRefExpr as an initialization or a use. Any
260 /// DeclRefExpr which isn't explicitly classified will be assumed to have
261 /// escaped the analysis and will be treated as an initialization.
262 class ClassifyRefs : public StmtVisitor<ClassifyRefs> {
263 public:
264  enum Class {
265  Init,
266  Use,
267  SelfInit,
268  ConstRefUse,
269  Ignore
270  };
271 
272 private:
273  const DeclContext *DC;
274  llvm::DenseMap<const DeclRefExpr *, Class> Classification;
275 
276  bool isTrackedVar(const VarDecl *VD) const {
277  return ::isTrackedVar(VD, DC);
278  }
279 
280  void classify(const Expr *E, Class C);
281 
282 public:
283  ClassifyRefs(AnalysisDeclContext &AC) : DC(cast<DeclContext>(AC.getDecl())) {}
284 
285  void VisitDeclStmt(DeclStmt *DS);
286  void VisitUnaryOperator(UnaryOperator *UO);
287  void VisitBinaryOperator(BinaryOperator *BO);
288  void VisitCallExpr(CallExpr *CE);
289  void VisitCastExpr(CastExpr *CE);
290  void VisitOMPExecutableDirective(OMPExecutableDirective *ED);
291 
292  void operator()(Stmt *S) { Visit(S); }
293 
294  Class get(const DeclRefExpr *DRE) const {
295  llvm::DenseMap<const DeclRefExpr*, Class>::const_iterator I
296  = Classification.find(DRE);
297  if (I != Classification.end())
298  return I->second;
299 
300  const auto *VD = dyn_cast<VarDecl>(DRE->getDecl());
301  if (!VD || !isTrackedVar(VD))
302  return Ignore;
303 
304  return Init;
305  }
306 };
307 
308 } // namespace
309 
310 static const DeclRefExpr *getSelfInitExpr(VarDecl *VD) {
311  if (VD->getType()->isRecordType())
312  return nullptr;
313  if (Expr *Init = VD->getInit()) {
314  const auto *DRE =
315  dyn_cast<DeclRefExpr>(stripCasts(VD->getASTContext(), Init));
316  if (DRE && DRE->getDecl() == VD)
317  return DRE;
318  }
319  return nullptr;
320 }
321 
322 void ClassifyRefs::classify(const Expr *E, Class C) {
323  // The result of a ?: could also be an lvalue.
324  E = E->IgnoreParens();
325  if (const auto *CO = dyn_cast<ConditionalOperator>(E)) {
326  classify(CO->getTrueExpr(), C);
327  classify(CO->getFalseExpr(), C);
328  return;
329  }
330 
331  if (const auto *BCO = dyn_cast<BinaryConditionalOperator>(E)) {
332  classify(BCO->getFalseExpr(), C);
333  return;
334  }
335 
336  if (const auto *OVE = dyn_cast<OpaqueValueExpr>(E)) {
337  classify(OVE->getSourceExpr(), C);
338  return;
339  }
340 
341  if (const auto *ME = dyn_cast<MemberExpr>(E)) {
342  if (const auto *VD = dyn_cast<VarDecl>(ME->getMemberDecl())) {
343  if (!VD->isStaticDataMember())
344  classify(ME->getBase(), C);
345  }
346  return;
347  }
348 
349  if (const auto *BO = dyn_cast<BinaryOperator>(E)) {
350  switch (BO->getOpcode()) {
351  case BO_PtrMemD:
352  case BO_PtrMemI:
353  classify(BO->getLHS(), C);
354  return;
355  case BO_Comma:
356  classify(BO->getRHS(), C);
357  return;
358  default:
359  return;
360  }
361  }
362 
363  FindVarResult Var = findVar(E, DC);
364  if (const DeclRefExpr *DRE = Var.getDeclRefExpr())
365  Classification[DRE] = std::max(Classification[DRE], C);
366 }
367 
368 void ClassifyRefs::VisitDeclStmt(DeclStmt *DS) {
369  for (auto *DI : DS->decls()) {
370  auto *VD = dyn_cast<VarDecl>(DI);
371  if (VD && isTrackedVar(VD))
372  if (const DeclRefExpr *DRE = getSelfInitExpr(VD))
373  Classification[DRE] = SelfInit;
374  }
375 }
376 
377 void ClassifyRefs::VisitBinaryOperator(BinaryOperator *BO) {
378  // Ignore the evaluation of a DeclRefExpr on the LHS of an assignment. If this
379  // is not a compound-assignment, we will treat it as initializing the variable
380  // when TransferFunctions visits it. A compound-assignment does not affect
381  // whether a variable is uninitialized, and there's no point counting it as a
382  // use.
383  if (BO->isCompoundAssignmentOp())
384  classify(BO->getLHS(), Use);
385  else if (BO->getOpcode() == BO_Assign || BO->getOpcode() == BO_Comma)
386  classify(BO->getLHS(), Ignore);
387 }
388 
389 void ClassifyRefs::VisitUnaryOperator(UnaryOperator *UO) {
390  // Increment and decrement are uses despite there being no lvalue-to-rvalue
391  // conversion.
392  if (UO->isIncrementDecrementOp())
393  classify(UO->getSubExpr(), Use);
394 }
395 
396 void ClassifyRefs::VisitOMPExecutableDirective(OMPExecutableDirective *ED) {
397  for (Stmt *S : OMPExecutableDirective::used_clauses_children(ED->clauses()))
398  classify(cast<Expr>(S), Use);
399 }
400 
401 static bool isPointerToConst(const QualType &QT) {
402  return QT->isAnyPointerType() && QT->getPointeeType().isConstQualified();
403 }
404 
405 static bool hasTrivialBody(CallExpr *CE) {
406  if (FunctionDecl *FD = CE->getDirectCallee()) {
407  if (FunctionTemplateDecl *FTD = FD->getPrimaryTemplate())
408  return FTD->getTemplatedDecl()->hasTrivialBody();
409  return FD->hasTrivialBody();
410  }
411  return false;
412 }
413 
414 void ClassifyRefs::VisitCallExpr(CallExpr *CE) {
415  // Classify arguments to std::move as used.
416  if (CE->isCallToStdMove()) {
417  // RecordTypes are handled in SemaDeclCXX.cpp.
418  if (!CE->getArg(0)->getType()->isRecordType())
419  classify(CE->getArg(0), Use);
420  return;
421  }
422  bool isTrivialBody = hasTrivialBody(CE);
423  // If a value is passed by const pointer to a function,
424  // we should not assume that it is initialized by the call, and we
425  // conservatively do not assume that it is used.
426  // If a value is passed by const reference to a function,
427  // it should already be initialized.
428  for (CallExpr::arg_iterator I = CE->arg_begin(), E = CE->arg_end();
429  I != E; ++I) {
430  if ((*I)->isGLValue()) {
431  if ((*I)->getType().isConstQualified())
432  classify((*I), isTrivialBody ? Ignore : ConstRefUse);
433  } else if (isPointerToConst((*I)->getType())) {
434  const Expr *Ex = stripCasts(DC->getParentASTContext(), *I);
435  const auto *UO = dyn_cast<UnaryOperator>(Ex);
436  if (UO && UO->getOpcode() == UO_AddrOf)
437  Ex = UO->getSubExpr();
438  classify(Ex, Ignore);
439  }
440  }
441 }
442 
443 void ClassifyRefs::VisitCastExpr(CastExpr *CE) {
444  if (CE->getCastKind() == CK_LValueToRValue)
445  classify(CE->getSubExpr(), Use);
446  else if (const auto *CSE = dyn_cast<CStyleCastExpr>(CE)) {
447  if (CSE->getType()->isVoidType()) {
448  // Squelch any detected load of an uninitialized value if
449  // we cast it to void.
450  // e.g. (void) x;
451  classify(CSE->getSubExpr(), Ignore);
452  }
453  }
454 }
455 
456 //------------------------------------------------------------------------====//
457 // Transfer function for uninitialized values analysis.
458 //====------------------------------------------------------------------------//
459 
460 namespace {
461 
462 class TransferFunctions : public StmtVisitor<TransferFunctions> {
463  CFGBlockValues &vals;
464  const CFG &cfg;
465  const CFGBlock *block;
467  const ClassifyRefs &classification;
468  ObjCNoReturn objCNoRet;
469  UninitVariablesHandler &handler;
470 
471 public:
472  TransferFunctions(CFGBlockValues &vals, const CFG &cfg,
473  const CFGBlock *block, AnalysisDeclContext &ac,
474  const ClassifyRefs &classification,
475  UninitVariablesHandler &handler)
476  : vals(vals), cfg(cfg), block(block), ac(ac),
477  classification(classification), objCNoRet(ac.getASTContext()),
478  handler(handler) {}
479 
480  void reportUse(const Expr *ex, const VarDecl *vd);
481  void reportConstRefUse(const Expr *ex, const VarDecl *vd);
482 
483  void VisitBinaryOperator(BinaryOperator *bo);
484  void VisitBlockExpr(BlockExpr *be);
485  void VisitCallExpr(CallExpr *ce);
486  void VisitDeclRefExpr(DeclRefExpr *dr);
487  void VisitDeclStmt(DeclStmt *ds);
488  void VisitGCCAsmStmt(GCCAsmStmt *as);
489  void VisitObjCForCollectionStmt(ObjCForCollectionStmt *FS);
490  void VisitObjCMessageExpr(ObjCMessageExpr *ME);
491  void VisitOMPExecutableDirective(OMPExecutableDirective *ED);
492 
493  bool isTrackedVar(const VarDecl *vd) {
494  return ::isTrackedVar(vd, cast<DeclContext>(ac.getDecl()));
495  }
496 
497  FindVarResult findVar(const Expr *ex) {
498  return ::findVar(ex, cast<DeclContext>(ac.getDecl()));
499  }
500 
501  UninitUse getUninitUse(const Expr *ex, const VarDecl *vd, Value v) {
502  UninitUse Use(ex, isAlwaysUninit(v));
503 
504  assert(isUninitialized(v));
505  if (Use.getKind() == UninitUse::Always)
506  return Use;
507 
508  // If an edge which leads unconditionally to this use did not initialize
509  // the variable, we can say something stronger than 'may be uninitialized':
510  // we can say 'either it's used uninitialized or you have dead code'.
511  //
512  // We track the number of successors of a node which have been visited, and
513  // visit a node once we have visited all of its successors. Only edges where
514  // the variable might still be uninitialized are followed. Since a variable
515  // can't transfer from being initialized to being uninitialized, this will
516  // trace out the subgraph which inevitably leads to the use and does not
517  // initialize the variable. We do not want to skip past loops, since their
518  // non-termination might be correlated with the initialization condition.
519  //
520  // For example:
521  //
522  // void f(bool a, bool b) {
523  // block1: int n;
524  // if (a) {
525  // block2: if (b)
526  // block3: n = 1;
527  // block4: } else if (b) {
528  // block5: while (!a) {
529  // block6: do_work(&a);
530  // n = 2;
531  // }
532  // }
533  // block7: if (a)
534  // block8: g();
535  // block9: return n;
536  // }
537  //
538  // Starting from the maybe-uninitialized use in block 9:
539  // * Block 7 is not visited because we have only visited one of its two
540  // successors.
541  // * Block 8 is visited because we've visited its only successor.
542  // From block 8:
543  // * Block 7 is visited because we've now visited both of its successors.
544  // From block 7:
545  // * Blocks 1, 2, 4, 5, and 6 are not visited because we didn't visit all
546  // of their successors (we didn't visit 4, 3, 5, 6, and 5, respectively).
547  // * Block 3 is not visited because it initializes 'n'.
548  // Now the algorithm terminates, having visited blocks 7 and 8, and having
549  // found the frontier is blocks 2, 4, and 5.
550  //
551  // 'n' is definitely uninitialized for two edges into block 7 (from blocks 2
552  // and 4), so we report that any time either of those edges is taken (in
553  // each case when 'b == false'), 'n' is used uninitialized.
555  SmallVector<unsigned, 32> SuccsVisited(cfg.getNumBlockIDs(), 0);
556  Queue.push_back(block);
557  // Specify that we've already visited all successors of the starting block.
558  // This has the dual purpose of ensuring we never add it to the queue, and
559  // of marking it as not being a candidate element of the frontier.
560  SuccsVisited[block->getBlockID()] = block->succ_size();
561  while (!Queue.empty()) {
562  const CFGBlock *B = Queue.pop_back_val();
563 
564  // If the use is always reached from the entry block, make a note of that.
565  if (B == &cfg.getEntry())
566  Use.setUninitAfterCall();
567 
568  for (CFGBlock::const_pred_iterator I = B->pred_begin(), E = B->pred_end();
569  I != E; ++I) {
570  const CFGBlock *Pred = *I;
571  if (!Pred)
572  continue;
573 
574  Value AtPredExit = vals.getValue(Pred, B, vd);
575  if (AtPredExit == Initialized)
576  // This block initializes the variable.
577  continue;
578  if (AtPredExit == MayUninitialized &&
579  vals.getValue(B, nullptr, vd) == Uninitialized) {
580  // This block declares the variable (uninitialized), and is reachable
581  // from a block that initializes the variable. We can't guarantee to
582  // give an earlier location for the diagnostic (and it appears that
583  // this code is intended to be reachable) so give a diagnostic here
584  // and go no further down this path.
585  Use.setUninitAfterDecl();
586  continue;
587  }
588 
589  if (AtPredExit == MayUninitialized) {
590  // If the predecessor's terminator is an "asm goto" that initializes
591  // the variable, then don't count it as "initialized" on the indirect
592  // paths.
593  CFGTerminator term = Pred->getTerminator();
594  if (const auto *as = dyn_cast_or_null<GCCAsmStmt>(term.getStmt())) {
595  const CFGBlock *fallthrough = *Pred->succ_begin();
596  if (as->isAsmGoto() &&
597  llvm::any_of(as->outputs(), [&](const Expr *output) {
598  return vd == findVar(output).getDecl() &&
599  llvm::any_of(as->labels(),
600  [&](const AddrLabelExpr *label) {
601  return label->getLabel()->getStmt() == B->Label &&
602  B != fallthrough;
603  });
604  })) {
605  Use.setUninitAfterDecl();
606  continue;
607  }
608  }
609  }
610 
611  unsigned &SV = SuccsVisited[Pred->getBlockID()];
612  if (!SV) {
613  // When visiting the first successor of a block, mark all NULL
614  // successors as having been visited.
615  for (CFGBlock::const_succ_iterator SI = Pred->succ_begin(),
616  SE = Pred->succ_end();
617  SI != SE; ++SI)
618  if (!*SI)
619  ++SV;
620  }
621 
622  if (++SV == Pred->succ_size())
623  // All paths from this block lead to the use and don't initialize the
624  // variable.
625  Queue.push_back(Pred);
626  }
627  }
628 
629  // Scan the frontier, looking for blocks where the variable was
630  // uninitialized.
631  for (const auto *Block : cfg) {
632  unsigned BlockID = Block->getBlockID();
633  const Stmt *Term = Block->getTerminatorStmt();
634  if (SuccsVisited[BlockID] && SuccsVisited[BlockID] < Block->succ_size() &&
635  Term) {
636  // This block inevitably leads to the use. If we have an edge from here
637  // to a post-dominator block, and the variable is uninitialized on that
638  // edge, we have found a bug.
639  for (CFGBlock::const_succ_iterator I = Block->succ_begin(),
640  E = Block->succ_end(); I != E; ++I) {
641  const CFGBlock *Succ = *I;
642  if (Succ && SuccsVisited[Succ->getBlockID()] >= Succ->succ_size() &&
643  vals.getValue(Block, Succ, vd) == Uninitialized) {
644  // Switch cases are a special case: report the label to the caller
645  // as the 'terminator', not the switch statement itself. Suppress
646  // situations where no label matched: we can't be sure that's
647  // possible.
648  if (isa<SwitchStmt>(Term)) {
649  const Stmt *Label = Succ->getLabel();
650  if (!Label || !isa<SwitchCase>(Label))
651  // Might not be possible.
652  continue;
653  UninitUse::Branch Branch;
654  Branch.Terminator = Label;
655  Branch.Output = 0; // Ignored.
656  Use.addUninitBranch(Branch);
657  } else {
658  UninitUse::Branch Branch;
659  Branch.Terminator = Term;
660  Branch.Output = I - Block->succ_begin();
661  Use.addUninitBranch(Branch);
662  }
663  }
664  }
665  }
666  }
667 
668  return Use;
669  }
670 };
671 
672 } // namespace
673 
674 void TransferFunctions::reportUse(const Expr *ex, const VarDecl *vd) {
675  Value v = vals[vd];
676  if (isUninitialized(v))
677  handler.handleUseOfUninitVariable(vd, getUninitUse(ex, vd, v));
678 }
679 
680 void TransferFunctions::reportConstRefUse(const Expr *ex, const VarDecl *vd) {
681  Value v = vals[vd];
682  if (isAlwaysUninit(v))
683  handler.handleConstRefUseOfUninitVariable(vd, getUninitUse(ex, vd, v));
684 }
685 
686 void TransferFunctions::VisitObjCForCollectionStmt(ObjCForCollectionStmt *FS) {
687  // This represents an initialization of the 'element' value.
688  if (const auto *DS = dyn_cast<DeclStmt>(FS->getElement())) {
689  const auto *VD = cast<VarDecl>(DS->getSingleDecl());
690  if (isTrackedVar(VD))
691  vals[VD] = Initialized;
692  }
693 }
694 
695 void TransferFunctions::VisitOMPExecutableDirective(
697  for (Stmt *S : OMPExecutableDirective::used_clauses_children(ED->clauses())) {
698  assert(S && "Expected non-null used-in-clause child.");
699  Visit(S);
700  }
701  if (!ED->isStandaloneDirective())
702  Visit(ED->getStructuredBlock());
703 }
704 
705 void TransferFunctions::VisitBlockExpr(BlockExpr *be) {
706  const BlockDecl *bd = be->getBlockDecl();
707  for (const auto &I : bd->captures()) {
708  const VarDecl *vd = I.getVariable();
709  if (!isTrackedVar(vd))
710  continue;
711  if (I.isByRef()) {
712  vals[vd] = Initialized;
713  continue;
714  }
715  reportUse(be, vd);
716  }
717 }
718 
719 void TransferFunctions::VisitCallExpr(CallExpr *ce) {
720  if (Decl *Callee = ce->getCalleeDecl()) {
721  if (Callee->hasAttr<ReturnsTwiceAttr>()) {
722  // After a call to a function like setjmp or vfork, any variable which is
723  // initialized anywhere within this function may now be initialized. For
724  // now, just assume such a call initializes all variables. FIXME: Only
725  // mark variables as initialized if they have an initializer which is
726  // reachable from here.
727  vals.setAllScratchValues(Initialized);
728  }
729  else if (Callee->hasAttr<AnalyzerNoReturnAttr>()) {
730  // Functions labeled like "analyzer_noreturn" are often used to denote
731  // "panic" functions that in special debug situations can still return,
732  // but for the most part should not be treated as returning. This is a
733  // useful annotation borrowed from the static analyzer that is useful for
734  // suppressing branch-specific false positives when we call one of these
735  // functions but keep pretending the path continues (when in reality the
736  // user doesn't care).
737  vals.setAllScratchValues(Unknown);
738  }
739  }
740 }
741 
742 void TransferFunctions::VisitDeclRefExpr(DeclRefExpr *dr) {
743  switch (classification.get(dr)) {
744  case ClassifyRefs::Ignore:
745  break;
746  case ClassifyRefs::Use:
747  reportUse(dr, cast<VarDecl>(dr->getDecl()));
748  break;
749  case ClassifyRefs::Init:
750  vals[cast<VarDecl>(dr->getDecl())] = Initialized;
751  break;
752  case ClassifyRefs::SelfInit:
753  handler.handleSelfInit(cast<VarDecl>(dr->getDecl()));
754  break;
755  case ClassifyRefs::ConstRefUse:
756  reportConstRefUse(dr, cast<VarDecl>(dr->getDecl()));
757  break;
758  }
759 }
760 
761 void TransferFunctions::VisitBinaryOperator(BinaryOperator *BO) {
762  if (BO->getOpcode() == BO_Assign) {
763  FindVarResult Var = findVar(BO->getLHS());
764  if (const VarDecl *VD = Var.getDecl())
765  vals[VD] = Initialized;
766  }
767 }
768 
769 void TransferFunctions::VisitDeclStmt(DeclStmt *DS) {
770  for (auto *DI : DS->decls()) {
771  auto *VD = dyn_cast<VarDecl>(DI);
772  if (VD && isTrackedVar(VD)) {
773  if (getSelfInitExpr(VD)) {
774  // If the initializer consists solely of a reference to itself, we
775  // explicitly mark the variable as uninitialized. This allows code
776  // like the following:
777  //
778  // int x = x;
779  //
780  // to deliberately leave a variable uninitialized. Different analysis
781  // clients can detect this pattern and adjust their reporting
782  // appropriately, but we need to continue to analyze subsequent uses
783  // of the variable.
784  vals[VD] = Uninitialized;
785  } else if (VD->getInit()) {
786  // Treat the new variable as initialized.
787  vals[VD] = Initialized;
788  } else {
789  // No initializer: the variable is now uninitialized. This matters
790  // for cases like:
791  // while (...) {
792  // int n;
793  // use(n);
794  // n = 0;
795  // }
796  // FIXME: Mark the variable as uninitialized whenever its scope is
797  // left, since its scope could be re-entered by a jump over the
798  // declaration.
799  vals[VD] = Uninitialized;
800  }
801  }
802  }
803 }
804 
805 void TransferFunctions::VisitGCCAsmStmt(GCCAsmStmt *as) {
806  // An "asm goto" statement is a terminator that may initialize some variables.
807  if (!as->isAsmGoto())
808  return;
809 
810  ASTContext &C = ac.getASTContext();
811  for (const Expr *O : as->outputs()) {
812  const Expr *Ex = stripCasts(C, O);
813 
814  // Strip away any unary operators. Invalid l-values are reported by other
815  // semantic analysis passes.
816  while (const auto *UO = dyn_cast<UnaryOperator>(Ex))
817  Ex = stripCasts(C, UO->getSubExpr());
818 
819  // Mark the variable as potentially uninitialized for those cases where
820  // it's used on an indirect path, where it's not guaranteed to be
821  // defined.
822  if (const VarDecl *VD = findVar(Ex).getDecl())
823  vals[VD] = MayUninitialized;
824  }
825 }
826 
827 void TransferFunctions::VisitObjCMessageExpr(ObjCMessageExpr *ME) {
828  // If the Objective-C message expression is an implicit no-return that
829  // is not modeled in the CFG, set the tracked dataflow values to Unknown.
830  if (objCNoRet.isImplicitNoReturn(ME)) {
831  vals.setAllScratchValues(Unknown);
832  }
833 }
834 
835 //------------------------------------------------------------------------====//
836 // High-level "driver" logic for uninitialized values analysis.
837 //====------------------------------------------------------------------------//
838 
839 static bool runOnBlock(const CFGBlock *block, const CFG &cfg,
840  AnalysisDeclContext &ac, CFGBlockValues &vals,
841  const ClassifyRefs &classification,
842  llvm::BitVector &wasAnalyzed,
843  UninitVariablesHandler &handler) {
844  wasAnalyzed[block->getBlockID()] = true;
845  vals.resetScratch();
846  // Merge in values of predecessor blocks.
847  bool isFirst = true;
848  for (CFGBlock::const_pred_iterator I = block->pred_begin(),
849  E = block->pred_end(); I != E; ++I) {
850  const CFGBlock *pred = *I;
851  if (!pred)
852  continue;
853  if (wasAnalyzed[pred->getBlockID()]) {
854  vals.mergeIntoScratch(vals.getValueVector(pred), isFirst);
855  isFirst = false;
856  }
857  }
858  // Apply the transfer function.
859  TransferFunctions tf(vals, cfg, block, ac, classification, handler);
860  for (const auto &I : *block) {
861  if (std::optional<CFGStmt> cs = I.getAs<CFGStmt>())
862  tf.Visit(const_cast<Stmt *>(cs->getStmt()));
863  }
864  CFGTerminator terminator = block->getTerminator();
865  if (auto *as = dyn_cast_or_null<GCCAsmStmt>(terminator.getStmt()))
866  if (as->isAsmGoto())
867  tf.Visit(as);
868  return vals.updateValueVectorWithScratch(block);
869 }
870 
871 namespace {
872 
873 /// PruneBlocksHandler is a special UninitVariablesHandler that is used
874 /// to detect when a CFGBlock has any *potential* use of an uninitialized
875 /// variable. It is mainly used to prune out work during the final
876 /// reporting pass.
877 struct PruneBlocksHandler : public UninitVariablesHandler {
878  /// Records if a CFGBlock had a potential use of an uninitialized variable.
879  llvm::BitVector hadUse;
880 
881  /// Records if any CFGBlock had a potential use of an uninitialized variable.
882  bool hadAnyUse = false;
883 
884  /// The current block to scribble use information.
885  unsigned currentBlock = 0;
886 
887  PruneBlocksHandler(unsigned numBlocks) : hadUse(numBlocks, false) {}
888 
889  ~PruneBlocksHandler() override = default;
890 
891  void handleUseOfUninitVariable(const VarDecl *vd,
892  const UninitUse &use) override {
893  hadUse[currentBlock] = true;
894  hadAnyUse = true;
895  }
896 
898  const UninitUse &use) override {
899  hadUse[currentBlock] = true;
900  hadAnyUse = true;
901  }
902 
903  /// Called when the uninitialized variable analysis detects the
904  /// idiom 'int x = x'. All other uses of 'x' within the initializer
905  /// are handled by handleUseOfUninitVariable.
906  void handleSelfInit(const VarDecl *vd) override {
907  hadUse[currentBlock] = true;
908  hadAnyUse = true;
909  }
910 };
911 
912 } // namespace
913 
915  const DeclContext &dc,
916  const CFG &cfg,
918  UninitVariablesHandler &handler,
920  CFGBlockValues vals(cfg);
921  vals.computeSetOfDeclarations(dc);
922  if (vals.hasNoDeclarations())
923  return;
924 
925  stats.NumVariablesAnalyzed = vals.getNumEntries();
926 
927  // Precompute which expressions are uses and which are initializations.
928  ClassifyRefs classification(ac);
929  cfg.VisitBlockStmts(classification);
930 
931  // Mark all variables uninitialized at the entry.
932  const CFGBlock &entry = cfg.getEntry();
933  ValueVector &vec = vals.getValueVector(&entry);
934  const unsigned n = vals.getNumEntries();
935  for (unsigned j = 0; j < n; ++j) {
936  vec[j] = Uninitialized;
937  }
938 
939  // Proceed with the workist.
940  ForwardDataflowWorklist worklist(cfg, ac);
941  llvm::BitVector previouslyVisited(cfg.getNumBlockIDs());
942  worklist.enqueueSuccessors(&cfg.getEntry());
943  llvm::BitVector wasAnalyzed(cfg.getNumBlockIDs(), false);
944  wasAnalyzed[cfg.getEntry().getBlockID()] = true;
945  PruneBlocksHandler PBH(cfg.getNumBlockIDs());
946 
947  while (const CFGBlock *block = worklist.dequeue()) {
948  PBH.currentBlock = block->getBlockID();
949 
950  // Did the block change?
951  bool changed = runOnBlock(block, cfg, ac, vals,
952  classification, wasAnalyzed, PBH);
953  ++stats.NumBlockVisits;
954  if (changed || !previouslyVisited[block->getBlockID()])
955  worklist.enqueueSuccessors(block);
956  previouslyVisited[block->getBlockID()] = true;
957  }
958 
959  if (!PBH.hadAnyUse)
960  return;
961 
962  // Run through the blocks one more time, and report uninitialized variables.
963  for (const auto *block : cfg)
964  if (PBH.hadUse[block->getBlockID()]) {
965  runOnBlock(block, cfg, ac, vals, classification, wasAnalyzed, handler);
966  ++stats.NumBlockVisits;
967  }
968 }
969 
970 UninitVariablesHandler::~UninitVariablesHandler() = default;
clang::StmtVisitor
StmtVisitor - This class implements a simple visitor for Stmt subclasses.
Definition: StmtVisitor.h:183
clang::CFGBlock::getTerminator
CFGTerminator getTerminator() const
Definition: CFG.h:1048
clang::UninitVariablesAnalysisStats::NumBlockVisits
unsigned NumBlockVisits
Definition: UninitializedValues.h:125
clang::Type::isRecordType
bool isRecordType() const
Definition: Type.h:6984
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__DEVICE__ int max(int __a, int __b)
Definition: __clang_cuda_math.h:196
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ASTContext & getASTContext() const LLVM_READONLY
Definition: DeclBase.cpp:428
clang::DeclContext::decls_end
decl_iterator decls_end() const
Definition: DeclBase.h:2184
clang::AnalysisDeclContext::getASTContext
ASTContext & getASTContext() const
Definition: AnalysisDeclContext.h:104
clang::CFG::VisitBlockStmts
void VisitBlockStmts(Callback &O) const
Definition: CFG.h:1397
clang::DeclContext::getParentASTContext
ASTContext & getParentASTContext() const
Definition: DeclBase.h:1956
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arg_iterator arg_end()
Definition: Expr.h:3059
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arg_iterator arg_begin()
Definition: Expr.h:3056
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specific_decl_iterator - Iterates over a subrange of declarations stored in a DeclContext,...
Definition: DeclBase.h:2202
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@ Class
clang::DeclContext
DeclContext - This is used only as base class of specific decl types that can act as declaration cont...
Definition: DeclBase.h:1389
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bool hasGlobalStorage() const
Returns true for all variables that do not have local storage.
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bool isConstQualified() const
Determine whether this type is const-qualified.
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unsigned succ_size() const
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unsigned getNumBlockIDs() const
Returns the total number of BlockIDs allocated (which start at 0).
Definition: CFG.h:1411
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AnalysisDeclContext.h
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Definition: LLVM.h:38
clang::VarDecl::isInitCapture
bool isInitCapture() const
Whether this variable is the implicit variable for a lambda init-capture.
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Expr * getSubExpr()
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unsigned getBlockID() const
Definition: CFG.h:1074
clang::QualType
A (possibly-)qualified type.
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Attr.h
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bool isScalarType() const
Definition: Type.h:7278
AttributeLangSupport::C
@ C
Definition: SemaDeclAttr.cpp:56
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U cast(CodeGen::Address addr)
Definition: Address.h:174
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AnalysisDeclContext contains the context data for the function, method or block under analysis.
Definition: AnalysisDeclContext.h:72
PostOrderCFGView.h
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virtual void handleSelfInit(const VarDecl *vd)
Called when the uninitialized variable analysis detects the idiom 'int x = x'.
Definition: UninitializedValues.h:120
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Expr * IgnoreParenNoopCasts(const ASTContext &Ctx) LLVM_READONLY
Skip past any parenthese and casts which do not change the value (including ptr->int casts of the sam...
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UnaryOperator - This represents the unary-expression's (except sizeof and alignof),...
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Definition: Expr.h:2976
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Represents Objective-C's collection statement.
Definition: StmtObjC.h:23
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Opcode getOpcode() const
Definition: Expr.h:3858
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AdjacentBlocks::const_iterator const_succ_iterator
Definition: CFG.h:931
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Represents a source-level, intra-procedural CFG that represents the control-flow of a Stmt.
Definition: CFG.h:1225
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static SVal getValue(SVal val, SValBuilder &svalBuilder)
Definition: ArrayBoundCheckerV2.cpp:277
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ArrayRef< Capture > captures() const
Definition: Decl.h:4459
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Stmt * getStmt()
Definition: CFG.h:535
clang::CFGBlock
Represents a single basic block in a source-level CFG.
Definition: CFG.h:576
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Definition: UninitializedValues.h:32
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static bool isUninitialized(const Value v)
Definition: UninitializedValues.cpp:107
clang::FunctionTemplateDecl
Declaration of a template function.
Definition: DeclTemplate.h:1005
Unknown
@ Unknown
Definition: UninitializedValues.cpp:102
V
#define V(N, I)
Definition: ASTContext.h:3211
clang::CallExpr::getDirectCallee
FunctionDecl * getDirectCallee()
If the callee is a FunctionDecl, return it. Otherwise return null.
Definition: Expr.h:2982
clang::BlockDecl
Represents a block literal declaration, which is like an unnamed FunctionDecl.
Definition: Decl.h:4332
clang::BinaryOperator
A builtin binary operation expression such as "x + y" or "x <= y".
Definition: Expr.h:3814
DeclBase.h
clang::UninitVariablesHandler::handleUseOfUninitVariable
virtual void handleUseOfUninitVariable(const VarDecl *vd, const UninitUse &use)
Called when the uninitialized variable is used at the given expression.
Definition: UninitializedValues.h:110
clang::UnaryOperator::isIncrementDecrementOp
static bool isIncrementDecrementOp(Opcode Op)
Definition: Expr.h:2276
clang::syntax::NodeRole::Callee
@ Callee
clang::BlockExpr::getBlockDecl
const BlockDecl * getBlockDecl() const
Definition: Expr.h:5985
clang::ASTContext
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:182
clang::Stmt::CastIterator
Iterator for iterating over Stmt * arrays that contain only T *.
Definition: Stmt.h:1133
clang::AsmStmt::outputs
outputs_range outputs()
Definition: Stmt.h:3020
UninitializedValues.h
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static bool isPointerToConst(const QualType &QT)
Definition: UninitializedValues.cpp:401
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static const DeclRefExpr * getSelfInitExpr(VarDecl *VD)
Definition: UninitializedValues.cpp:310
clang::OMPExecutableDirective::isStandaloneDirective
bool isStandaloneDirective() const
Returns whether or not this is a Standalone directive.
Definition: StmtOpenMP.cpp:58
clang::CallExpr::getArg
Expr * getArg(unsigned Arg)
getArg - Return the specified argument.
Definition: Expr.h:3003
clang::StmtVisitorBase< std::add_pointer, ImplClass, void, ParamTys... >::Visit
void Visit(PTR(Stmt) S, ParamTys... P)
Definition: StmtVisitor.h:43
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bool isVectorType() const
Definition: Type.h:6996
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Definition: UninitializedValues.h:104
MayUninitialized
@ MayUninitialized
Definition: UninitializedValues.cpp:105
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BlockID
The various types of blocks that can occur within a API notes file.
Definition: APINotesFormat.h:38
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ValueDecl * getDecl()
Definition: Expr.h:1306
Type.h
Expr.h
clang::VarDecl
Represents a variable declaration or definition.
Definition: Decl.h:915
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QualType getPointeeType() const
If this is a pointer, ObjC object pointer, or block pointer, this returns the respective pointee.
Definition: Type.cpp:629
OperationKinds.h
clang::VarDecl::isLocalVarDecl
bool isLocalVarDecl() const
Returns true for local variable declarations other than parameters.
Definition: Decl.h:1212
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unsigned Output
Definition: UninitializedValues.h:34
clang::UninitVariablesHandler::handleConstRefUseOfUninitVariable
virtual void handleConstRefUseOfUninitVariable(const VarDecl *vd, const UninitUse &use)
Called when the uninitialized variable is used as const refernce argument.
Definition: UninitializedValues.h:114
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Definition: UsingDeclarationsSorter.cpp:96
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const Stmt * Terminator
Definition: UninitializedValues.h:33
clang::CFGTerminator
Represents CFGBlock terminator statement.
Definition: CFG.h:503
DataflowWorklist.h
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An expression that sends a message to the given Objective-C object or class.
Definition: ExprObjC.h:940
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Definition: UninitializedValues.h:123
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CastKind getCastKind() const
Definition: Expr.h:3526
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bool isImplicit() const
isImplicit - Indicates whether the declaration was implicitly generated by the implementation.
Definition: DeclBase.h:576
StmtObjC.h
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const Stmt * getStructuredBlock() const
Returns the AST node representing OpenMP structured-block of this OpenMP executable directive,...
Definition: StmtOpenMP.h:588
ObjCNoReturn.h
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This represents a GCC inline-assembly statement extension.
Definition: Stmt.h:3046
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unsigned NumVariablesAnalyzed
Definition: UninitializedValues.h:124
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const Decl * getSingleDecl() const
Definition: Stmt.h:1326
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Definition: CFG.h:130
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A worklist implementation for forward dataflow analysis.
Definition: DataflowWorklist.h:62
false
#define false
Definition: stdbool.h:22
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bool isAsmGoto() const
Definition: Stmt.h:3191
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succ_iterator succ_end()
Definition: CFG.h:956
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Expr * getLHS() const
Definition: Expr.h:3863
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static const Expr * stripCasts(ASTContext &C, const Expr *Ex)
Definition: UninitializedValues.cpp:232
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static bool isTrackedVar(const VarDecl *vd, const DeclContext *dc)
Definition: UninitializedValues.cpp:43
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BlockExpr - Adaptor class for mixing a BlockDecl with expressions.
Definition: Expr.h:5973
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Stmt * getLabel()
Definition: CFG.h:1069
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bool isCallToStdMove() const
Definition: Expr.cpp:3458
Value
Value
Definition: UninitializedValues.cpp:102
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Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:83
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pred_iterator pred_begin()
Definition: CFG.h:937
StmtVisitor.h
LLVM.h
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const CFGBlock * dequeue()
Definition: DataflowWorklist.h:42
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CFGBlock & getEntry()
Definition: CFG.h:1331
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Definition: ObjCNoReturn.h:24
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const Expr * getInit() const
Definition: Decl.h:1327
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bool isImplicitNoReturn(const ObjCMessageExpr *ME)
Return true if the given message expression is known to never return.
Definition: ObjCNoReturn.cpp:48
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void enqueueSuccessors(const CFGBlock *Block)
Definition: DataflowWorklist.h:71
clang::OMPExecutableDirective
This is a basic class for representing single OpenMP executable directive.
Definition: StmtOpenMP.h:266
clang::DeclStmt
DeclStmt - Adaptor class for mixing declarations with statements and expressions.
Definition: Stmt.h:1311
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bool isRVVType() const
Definition: Type.h:7148
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static bool isCompoundAssignmentOp(Opcode Opc)
Definition: Expr.h:3954
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static bool isAlwaysUninit(const Value v)
Definition: UninitializedValues.cpp:111
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Expr * getSubExpr() const
Definition: Expr.h:2221
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Expr * IgnoreParens() LLVM_READONLY
Skip past any parentheses which might surround this expression until reaching a fixed point.
Definition: Expr.cpp:3032
clang
Definition: CalledOnceCheck.h:17
clang::Type::isAnyPointerType
bool isAnyPointerType() const
Definition: Type.h:6898
CFG.h
clang::AnalysisDeclContext::getDecl
const Decl * getDecl() const
Definition: AnalysisDeclContext.h:106
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@ Block
clang::Stmt
Stmt - This represents one statement.
Definition: Stmt.h:72
runOnBlock
static bool runOnBlock(const CFGBlock *block, const CFG &cfg, AnalysisDeclContext &ac, CFGBlockValues &vals, const ClassifyRefs &classification, llvm::BitVector &wasAnalyzed, UninitVariablesHandler &handler)
Definition: UninitializedValues.cpp:839
clang::UnaryOperator::getOpcode
Opcode getOpcode() const
Definition: Expr.h:2216
findVar
static FindVarResult findVar(const Expr *E, const DeclContext *DC)
If E is an expression comprising a reference to a single variable, find that variable.
Definition: UninitializedValues.cpp:248
clang::Expr::getType
QualType getType() const
Definition: Expr.h:142
Initialized
@ Initialized
Definition: UninitializedValues.cpp:103
clang::DeclStmt::decls
decl_range decls()
Definition: Stmt.h:1359
clang::runUninitializedVariablesAnalysis
void runUninitializedVariablesAnalysis(const DeclContext &dc, const CFG &cfg, AnalysisDeclContext &ac, UninitVariablesHandler &handler, UninitVariablesAnalysisStats &stats)
Definition: UninitializedValues.cpp:914
Uninitialized
@ Uninitialized
Definition: UninitializedValues.cpp:104
c
__device__ __2f16 float c
Definition: __clang_hip_libdevice_declares.h:320
clang::OMPExecutableDirective::clauses
ArrayRef< OMPClause * > clauses() const
Definition: StmtOpenMP.h:573
v
do v
Definition: arm_acle.h:76
hasTrivialBody
static bool hasTrivialBody(CallExpr *CE)
Definition: UninitializedValues.cpp:405
Stmt.h
clang::ValueDecl::getType
QualType getType() const
Definition: Decl.h:714
clang::Expr
This represents one expression.
Definition: Expr.h:110
clang::CastExpr
CastExpr - Base class for type casts, including both implicit casts (ImplicitCastExpr) and explicit c...
Definition: Expr.h:3482
clang::VarDecl::isExceptionVariable
bool isExceptionVariable() const
Determine whether this variable is the exception variable in a C++ catch statememt or an Objective-C ...
Definition: Decl.h:1446
clang::DeclRefExpr
A reference to a declared variable, function, enum, etc.
Definition: Expr.h:1234
clang::FunctionDecl
Represents a function declaration or definition.
Definition: Decl.h:1917
clang::CallExpr
CallExpr - Represents a function call (C99 6.5.2.2, C++ [expr.call]).
Definition: Expr.h:2812
clang::UninitUse
A use of a variable, which might be uninitialized.
Definition: UninitializedValues.h:30
clang::CFGBlock::pred_end
pred_iterator pred_end()
Definition: CFG.h:938
clang::CFGBlock::const_pred_iterator
AdjacentBlocks::const_iterator const_pred_iterator
Definition: CFG.h:924
clang::Decl::getDeclContext
DeclContext * getDeclContext()
Definition: DeclBase.h:441
clang::DeclContext::decls_begin
decl_iterator decls_begin() const
Definition: DeclBase.cpp:1463