clang  8.0.0svn
CFG.cpp
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1 //===- CFG.cpp - Classes for representing and building CFGs ---------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines the CFG and CFGBuilder classes for representing and
11 // building Control-Flow Graphs (CFGs) from ASTs.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "clang/Analysis/CFG.h"
16 #include "clang/AST/ASTContext.h"
17 #include "clang/AST/Attr.h"
18 #include "clang/AST/Decl.h"
19 #include "clang/AST/DeclBase.h"
20 #include "clang/AST/DeclCXX.h"
21 #include "clang/AST/DeclGroup.h"
22 #include "clang/AST/Expr.h"
23 #include "clang/AST/ExprCXX.h"
26 #include "clang/AST/Stmt.h"
27 #include "clang/AST/StmtCXX.h"
28 #include "clang/AST/StmtObjC.h"
29 #include "clang/AST/StmtVisitor.h"
30 #include "clang/AST/Type.h"
33 #include "clang/Basic/Builtins.h"
35 #include "clang/Basic/LLVM.h"
38 #include "clang/Basic/Specifiers.h"
39 #include "llvm/ADT/APInt.h"
40 #include "llvm/ADT/APSInt.h"
41 #include "llvm/ADT/ArrayRef.h"
42 #include "llvm/ADT/DenseMap.h"
43 #include "llvm/ADT/Optional.h"
44 #include "llvm/ADT/STLExtras.h"
45 #include "llvm/ADT/SetVector.h"
46 #include "llvm/ADT/SmallPtrSet.h"
47 #include "llvm/ADT/SmallVector.h"
48 #include "llvm/Support/Allocator.h"
49 #include "llvm/Support/Casting.h"
50 #include "llvm/Support/Compiler.h"
51 #include "llvm/Support/DOTGraphTraits.h"
52 #include "llvm/Support/ErrorHandling.h"
53 #include "llvm/Support/Format.h"
54 #include "llvm/Support/GraphWriter.h"
55 #include "llvm/Support/SaveAndRestore.h"
56 #include "llvm/Support/raw_ostream.h"
57 #include <cassert>
58 #include <memory>
59 #include <string>
60 #include <tuple>
61 #include <utility>
62 #include <vector>
63 
64 using namespace clang;
65 
67  if (VarDecl *VD = dyn_cast<VarDecl>(D))
68  if (Expr *Ex = VD->getInit())
69  return Ex->getSourceRange().getEnd();
70  return D->getLocation();
71 }
72 
73 /// Helper for tryNormalizeBinaryOperator. Attempts to extract an IntegerLiteral
74 /// or EnumConstantDecl from the given Expr. If it fails, returns nullptr.
75 static const Expr *tryTransformToIntOrEnumConstant(const Expr *E) {
76  E = E->IgnoreParens();
77  if (isa<IntegerLiteral>(E))
78  return E;
79  if (auto *DR = dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))
80  return isa<EnumConstantDecl>(DR->getDecl()) ? DR : nullptr;
81  return nullptr;
82 }
83 
84 /// Tries to interpret a binary operator into `Decl Op Expr` form, if Expr is
85 /// an integer literal or an enum constant.
86 ///
87 /// If this fails, at least one of the returned DeclRefExpr or Expr will be
88 /// null.
89 static std::tuple<const DeclRefExpr *, BinaryOperatorKind, const Expr *>
91  BinaryOperatorKind Op = B->getOpcode();
92 
93  const Expr *MaybeDecl = B->getLHS();
94  const Expr *Constant = tryTransformToIntOrEnumConstant(B->getRHS());
95  // Expr looked like `0 == Foo` instead of `Foo == 0`
96  if (Constant == nullptr) {
97  // Flip the operator
98  if (Op == BO_GT)
99  Op = BO_LT;
100  else if (Op == BO_GE)
101  Op = BO_LE;
102  else if (Op == BO_LT)
103  Op = BO_GT;
104  else if (Op == BO_LE)
105  Op = BO_GE;
106 
107  MaybeDecl = B->getRHS();
108  Constant = tryTransformToIntOrEnumConstant(B->getLHS());
109  }
110 
111  auto *D = dyn_cast<DeclRefExpr>(MaybeDecl->IgnoreParenImpCasts());
112  return std::make_tuple(D, Op, Constant);
113 }
114 
115 /// For an expression `x == Foo && x == Bar`, this determines whether the
116 /// `Foo` and `Bar` are either of the same enumeration type, or both integer
117 /// literals.
118 ///
119 /// It's an error to pass this arguments that are not either IntegerLiterals
120 /// or DeclRefExprs (that have decls of type EnumConstantDecl)
121 static bool areExprTypesCompatible(const Expr *E1, const Expr *E2) {
122  // User intent isn't clear if they're mixing int literals with enum
123  // constants.
124  if (isa<IntegerLiteral>(E1) != isa<IntegerLiteral>(E2))
125  return false;
126 
127  // Integer literal comparisons, regardless of literal type, are acceptable.
128  if (isa<IntegerLiteral>(E1))
129  return true;
130 
131  // IntegerLiterals are handled above and only EnumConstantDecls are expected
132  // beyond this point
133  assert(isa<DeclRefExpr>(E1) && isa<DeclRefExpr>(E2));
134  auto *Decl1 = cast<DeclRefExpr>(E1)->getDecl();
135  auto *Decl2 = cast<DeclRefExpr>(E2)->getDecl();
136 
137  assert(isa<EnumConstantDecl>(Decl1) && isa<EnumConstantDecl>(Decl2));
138  const DeclContext *DC1 = Decl1->getDeclContext();
139  const DeclContext *DC2 = Decl2->getDeclContext();
140 
141  assert(isa<EnumDecl>(DC1) && isa<EnumDecl>(DC2));
142  return DC1 == DC2;
143 }
144 
145 namespace {
146 
147 class CFGBuilder;
148 
149 /// The CFG builder uses a recursive algorithm to build the CFG. When
150 /// we process an expression, sometimes we know that we must add the
151 /// subexpressions as block-level expressions. For example:
152 ///
153 /// exp1 || exp2
154 ///
155 /// When processing the '||' expression, we know that exp1 and exp2
156 /// need to be added as block-level expressions, even though they
157 /// might not normally need to be. AddStmtChoice records this
158 /// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then
159 /// the builder has an option not to add a subexpression as a
160 /// block-level expression.
161 class AddStmtChoice {
162 public:
163  enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 };
164 
165  AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {}
166 
167  bool alwaysAdd(CFGBuilder &builder,
168  const Stmt *stmt) const;
169 
170  /// Return a copy of this object, except with the 'always-add' bit
171  /// set as specified.
172  AddStmtChoice withAlwaysAdd(bool alwaysAdd) const {
173  return AddStmtChoice(alwaysAdd ? AlwaysAdd : NotAlwaysAdd);
174  }
175 
176 private:
177  Kind kind;
178 };
179 
180 /// LocalScope - Node in tree of local scopes created for C++ implicit
181 /// destructor calls generation. It contains list of automatic variables
182 /// declared in the scope and link to position in previous scope this scope
183 /// began in.
184 ///
185 /// The process of creating local scopes is as follows:
186 /// - Init CFGBuilder::ScopePos with invalid position (equivalent for null),
187 /// - Before processing statements in scope (e.g. CompoundStmt) create
188 /// LocalScope object using CFGBuilder::ScopePos as link to previous scope
189 /// and set CFGBuilder::ScopePos to the end of new scope,
190 /// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points
191 /// at this VarDecl,
192 /// - For every normal (without jump) end of scope add to CFGBlock destructors
193 /// for objects in the current scope,
194 /// - For every jump add to CFGBlock destructors for objects
195 /// between CFGBuilder::ScopePos and local scope position saved for jump
196 /// target. Thanks to C++ restrictions on goto jumps we can be sure that
197 /// jump target position will be on the path to root from CFGBuilder::ScopePos
198 /// (adding any variable that doesn't need constructor to be called to
199 /// LocalScope can break this assumption),
200 ///
201 class LocalScope {
202 public:
203  friend class const_iterator;
204 
205  using AutomaticVarsTy = BumpVector<VarDecl *>;
206 
207  /// const_iterator - Iterates local scope backwards and jumps to previous
208  /// scope on reaching the beginning of currently iterated scope.
209  class const_iterator {
210  const LocalScope* Scope = nullptr;
211 
212  /// VarIter is guaranteed to be greater then 0 for every valid iterator.
213  /// Invalid iterator (with null Scope) has VarIter equal to 0.
214  unsigned VarIter = 0;
215 
216  public:
217  /// Create invalid iterator. Dereferencing invalid iterator is not allowed.
218  /// Incrementing invalid iterator is allowed and will result in invalid
219  /// iterator.
220  const_iterator() = default;
221 
222  /// Create valid iterator. In case when S.Prev is an invalid iterator and
223  /// I is equal to 0, this will create invalid iterator.
224  const_iterator(const LocalScope& S, unsigned I)
225  : Scope(&S), VarIter(I) {
226  // Iterator to "end" of scope is not allowed. Handle it by going up
227  // in scopes tree possibly up to invalid iterator in the root.
228  if (VarIter == 0 && Scope)
229  *this = Scope->Prev;
230  }
231 
232  VarDecl *const* operator->() const {
233  assert(Scope && "Dereferencing invalid iterator is not allowed");
234  assert(VarIter != 0 && "Iterator has invalid value of VarIter member");
235  return &Scope->Vars[VarIter - 1];
236  }
237 
238  const VarDecl *getFirstVarInScope() const {
239  assert(Scope && "Dereferencing invalid iterator is not allowed");
240  assert(VarIter != 0 && "Iterator has invalid value of VarIter member");
241  return Scope->Vars[0];
242  }
243 
244  VarDecl *operator*() const {
245  return *this->operator->();
246  }
247 
248  const_iterator &operator++() {
249  if (!Scope)
250  return *this;
251 
252  assert(VarIter != 0 && "Iterator has invalid value of VarIter member");
253  --VarIter;
254  if (VarIter == 0)
255  *this = Scope->Prev;
256  return *this;
257  }
258  const_iterator operator++(int) {
259  const_iterator P = *this;
260  ++*this;
261  return P;
262  }
263 
264  bool operator==(const const_iterator &rhs) const {
265  return Scope == rhs.Scope && VarIter == rhs.VarIter;
266  }
267  bool operator!=(const const_iterator &rhs) const {
268  return !(*this == rhs);
269  }
270 
271  explicit operator bool() const {
272  return *this != const_iterator();
273  }
274 
275  int distance(const_iterator L);
276  const_iterator shared_parent(const_iterator L);
277  bool pointsToFirstDeclaredVar() { return VarIter == 1; }
278  };
279 
280 private:
281  BumpVectorContext ctx;
282 
283  /// Automatic variables in order of declaration.
284  AutomaticVarsTy Vars;
285 
286  /// Iterator to variable in previous scope that was declared just before
287  /// begin of this scope.
288  const_iterator Prev;
289 
290 public:
291  /// Constructs empty scope linked to previous scope in specified place.
292  LocalScope(BumpVectorContext ctx, const_iterator P)
293  : ctx(std::move(ctx)), Vars(this->ctx, 4), Prev(P) {}
294 
295  /// Begin of scope in direction of CFG building (backwards).
296  const_iterator begin() const { return const_iterator(*this, Vars.size()); }
297 
298  void addVar(VarDecl *VD) {
299  Vars.push_back(VD, ctx);
300  }
301 };
302 
303 } // namespace
304 
305 /// distance - Calculates distance from this to L. L must be reachable from this
306 /// (with use of ++ operator). Cost of calculating the distance is linear w.r.t.
307 /// number of scopes between this and L.
308 int LocalScope::const_iterator::distance(LocalScope::const_iterator L) {
309  int D = 0;
310  const_iterator F = *this;
311  while (F.Scope != L.Scope) {
312  assert(F != const_iterator() &&
313  "L iterator is not reachable from F iterator.");
314  D += F.VarIter;
315  F = F.Scope->Prev;
316  }
317  D += F.VarIter - L.VarIter;
318  return D;
319 }
320 
321 /// Calculates the closest parent of this iterator
322 /// that is in a scope reachable through the parents of L.
323 /// I.e. when using 'goto' from this to L, the lifetime of all variables
324 /// between this and shared_parent(L) end.
325 LocalScope::const_iterator
326 LocalScope::const_iterator::shared_parent(LocalScope::const_iterator L) {
327  llvm::SmallPtrSet<const LocalScope *, 4> ScopesOfL;
328  while (true) {
329  ScopesOfL.insert(L.Scope);
330  if (L == const_iterator())
331  break;
332  L = L.Scope->Prev;
333  }
334 
335  const_iterator F = *this;
336  while (true) {
337  if (ScopesOfL.count(F.Scope))
338  return F;
339  assert(F != const_iterator() &&
340  "L iterator is not reachable from F iterator.");
341  F = F.Scope->Prev;
342  }
343 }
344 
345 namespace {
346 
347 /// Structure for specifying position in CFG during its build process. It
348 /// consists of CFGBlock that specifies position in CFG and
349 /// LocalScope::const_iterator that specifies position in LocalScope graph.
350 struct BlockScopePosPair {
351  CFGBlock *block = nullptr;
352  LocalScope::const_iterator scopePosition;
353 
354  BlockScopePosPair() = default;
355  BlockScopePosPair(CFGBlock *b, LocalScope::const_iterator scopePos)
356  : block(b), scopePosition(scopePos) {}
357 };
358 
359 /// TryResult - a class representing a variant over the values
360 /// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool,
361 /// and is used by the CFGBuilder to decide if a branch condition
362 /// can be decided up front during CFG construction.
363 class TryResult {
364  int X = -1;
365 
366 public:
367  TryResult() = default;
368  TryResult(bool b) : X(b ? 1 : 0) {}
369 
370  bool isTrue() const { return X == 1; }
371  bool isFalse() const { return X == 0; }
372  bool isKnown() const { return X >= 0; }
373 
374  void negate() {
375  assert(isKnown());
376  X ^= 0x1;
377  }
378 };
379 
380 } // namespace
381 
382 static TryResult bothKnownTrue(TryResult R1, TryResult R2) {
383  if (!R1.isKnown() || !R2.isKnown())
384  return TryResult();
385  return TryResult(R1.isTrue() && R2.isTrue());
386 }
387 
388 namespace {
389 
390 class reverse_children {
391  llvm::SmallVector<Stmt *, 12> childrenBuf;
393 
394 public:
395  reverse_children(Stmt *S);
396 
397  using iterator = ArrayRef<Stmt *>::reverse_iterator;
398 
399  iterator begin() const { return children.rbegin(); }
400  iterator end() const { return children.rend(); }
401 };
402 
403 } // namespace
404 
405 reverse_children::reverse_children(Stmt *S) {
406  if (CallExpr *CE = dyn_cast<CallExpr>(S)) {
407  children = CE->getRawSubExprs();
408  return;
409  }
410  switch (S->getStmtClass()) {
411  // Note: Fill in this switch with more cases we want to optimize.
412  case Stmt::InitListExprClass: {
413  InitListExpr *IE = cast<InitListExpr>(S);
414  children = llvm::makeArrayRef(reinterpret_cast<Stmt**>(IE->getInits()),
415  IE->getNumInits());
416  return;
417  }
418  default:
419  break;
420  }
421 
422  // Default case for all other statements.
423  for (Stmt *SubStmt : S->children())
424  childrenBuf.push_back(SubStmt);
425 
426  // This needs to be done *after* childrenBuf has been populated.
427  children = childrenBuf;
428 }
429 
430 namespace {
431 
432 /// CFGBuilder - This class implements CFG construction from an AST.
433 /// The builder is stateful: an instance of the builder should be used to only
434 /// construct a single CFG.
435 ///
436 /// Example usage:
437 ///
438 /// CFGBuilder builder;
439 /// std::unique_ptr<CFG> cfg = builder.buildCFG(decl, stmt1);
440 ///
441 /// CFG construction is done via a recursive walk of an AST. We actually parse
442 /// the AST in reverse order so that the successor of a basic block is
443 /// constructed prior to its predecessor. This allows us to nicely capture
444 /// implicit fall-throughs without extra basic blocks.
445 class CFGBuilder {
446  using JumpTarget = BlockScopePosPair;
447  using JumpSource = BlockScopePosPair;
448 
449  ASTContext *Context;
450  std::unique_ptr<CFG> cfg;
451 
452  // Current block.
453  CFGBlock *Block = nullptr;
454 
455  // Block after the current block.
456  CFGBlock *Succ = nullptr;
457 
458  JumpTarget ContinueJumpTarget;
459  JumpTarget BreakJumpTarget;
460  JumpTarget SEHLeaveJumpTarget;
461  CFGBlock *SwitchTerminatedBlock = nullptr;
462  CFGBlock *DefaultCaseBlock = nullptr;
463 
464  // This can point either to a try or a __try block. The frontend forbids
465  // mixing both kinds in one function, so having one for both is enough.
466  CFGBlock *TryTerminatedBlock = nullptr;
467 
468  // Current position in local scope.
469  LocalScope::const_iterator ScopePos;
470 
471  // LabelMap records the mapping from Label expressions to their jump targets.
472  using LabelMapTy = llvm::DenseMap<LabelDecl *, JumpTarget>;
473  LabelMapTy LabelMap;
474 
475  // A list of blocks that end with a "goto" that must be backpatched to their
476  // resolved targets upon completion of CFG construction.
477  using BackpatchBlocksTy = std::vector<JumpSource>;
478  BackpatchBlocksTy BackpatchBlocks;
479 
480  // A list of labels whose address has been taken (for indirect gotos).
481  using LabelSetTy = llvm::SmallSetVector<LabelDecl *, 8>;
482  LabelSetTy AddressTakenLabels;
483 
484  // Information about the currently visited C++ object construction site.
485  // This is set in the construction trigger and read when the constructor
486  // or a function that returns an object by value is being visited.
487  llvm::DenseMap<Expr *, const ConstructionContextLayer *>
488  ConstructionContextMap;
489 
490  using DeclsWithEndedScopeSetTy = llvm::SmallSetVector<VarDecl *, 16>;
491  DeclsWithEndedScopeSetTy DeclsWithEndedScope;
492 
493  bool badCFG = false;
494  const CFG::BuildOptions &BuildOpts;
495 
496  // State to track for building switch statements.
497  bool switchExclusivelyCovered = false;
498  Expr::EvalResult *switchCond = nullptr;
499 
500  CFG::BuildOptions::ForcedBlkExprs::value_type *cachedEntry = nullptr;
501  const Stmt *lastLookup = nullptr;
502 
503  // Caches boolean evaluations of expressions to avoid multiple re-evaluations
504  // during construction of branches for chained logical operators.
505  using CachedBoolEvalsTy = llvm::DenseMap<Expr *, TryResult>;
506  CachedBoolEvalsTy CachedBoolEvals;
507 
508 public:
509  explicit CFGBuilder(ASTContext *astContext,
510  const CFG::BuildOptions &buildOpts)
511  : Context(astContext), cfg(new CFG()), // crew a new CFG
512  ConstructionContextMap(), BuildOpts(buildOpts) {}
513 
514 
515  // buildCFG - Used by external clients to construct the CFG.
516  std::unique_ptr<CFG> buildCFG(const Decl *D, Stmt *Statement);
517 
518  bool alwaysAdd(const Stmt *stmt);
519 
520 private:
521  // Visitors to walk an AST and construct the CFG.
522  CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc);
523  CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc);
524  CFGBlock *VisitBreakStmt(BreakStmt *B);
525  CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc);
526  CFGBlock *VisitCaseStmt(CaseStmt *C);
527  CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc);
528  CFGBlock *VisitCompoundStmt(CompoundStmt *C);
529  CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C,
530  AddStmtChoice asc);
531  CFGBlock *VisitContinueStmt(ContinueStmt *C);
532  CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
533  AddStmtChoice asc);
534  CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S);
535  CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc);
536  CFGBlock *VisitCXXNewExpr(CXXNewExpr *DE, AddStmtChoice asc);
537  CFGBlock *VisitCXXDeleteExpr(CXXDeleteExpr *DE, AddStmtChoice asc);
538  CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S);
539  CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
540  AddStmtChoice asc);
541  CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
542  AddStmtChoice asc);
543  CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T);
544  CFGBlock *VisitCXXTryStmt(CXXTryStmt *S);
545  CFGBlock *VisitDeclStmt(DeclStmt *DS);
546  CFGBlock *VisitDeclSubExpr(DeclStmt *DS);
547  CFGBlock *VisitDefaultStmt(DefaultStmt *D);
548  CFGBlock *VisitDoStmt(DoStmt *D);
549  CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, AddStmtChoice asc);
550  CFGBlock *VisitForStmt(ForStmt *F);
551  CFGBlock *VisitGotoStmt(GotoStmt *G);
552  CFGBlock *VisitIfStmt(IfStmt *I);
553  CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc);
554  CFGBlock *VisitConstantExpr(ConstantExpr *E, AddStmtChoice asc);
555  CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I);
556  CFGBlock *VisitLabelStmt(LabelStmt *L);
557  CFGBlock *VisitBlockExpr(BlockExpr *E, AddStmtChoice asc);
558  CFGBlock *VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc);
559  CFGBlock *VisitLogicalOperator(BinaryOperator *B);
560  std::pair<CFGBlock *, CFGBlock *> VisitLogicalOperator(BinaryOperator *B,
561  Stmt *Term,
562  CFGBlock *TrueBlock,
563  CFGBlock *FalseBlock);
564  CFGBlock *VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *MTE,
565  AddStmtChoice asc);
566  CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc);
567  CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S);
568  CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S);
569  CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S);
570  CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S);
571  CFGBlock *VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S);
572  CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S);
573  CFGBlock *VisitObjCMessageExpr(ObjCMessageExpr *E, AddStmtChoice asc);
574  CFGBlock *VisitPseudoObjectExpr(PseudoObjectExpr *E);
575  CFGBlock *VisitReturnStmt(Stmt *S);
576  CFGBlock *VisitSEHExceptStmt(SEHExceptStmt *S);
577  CFGBlock *VisitSEHFinallyStmt(SEHFinallyStmt *S);
578  CFGBlock *VisitSEHLeaveStmt(SEHLeaveStmt *S);
579  CFGBlock *VisitSEHTryStmt(SEHTryStmt *S);
580  CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc);
581  CFGBlock *VisitSwitchStmt(SwitchStmt *S);
582  CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
583  AddStmtChoice asc);
584  CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc);
585  CFGBlock *VisitWhileStmt(WhileStmt *W);
586 
587  CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd);
588  CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc);
589  CFGBlock *VisitChildren(Stmt *S);
590  CFGBlock *VisitNoRecurse(Expr *E, AddStmtChoice asc);
591 
592  void maybeAddScopeBeginForVarDecl(CFGBlock *B, const VarDecl *VD,
593  const Stmt *S) {
594  if (ScopePos && (VD == ScopePos.getFirstVarInScope()))
595  appendScopeBegin(B, VD, S);
596  }
597 
598  /// When creating the CFG for temporary destructors, we want to mirror the
599  /// branch structure of the corresponding constructor calls.
600  /// Thus, while visiting a statement for temporary destructors, we keep a
601  /// context to keep track of the following information:
602  /// - whether a subexpression is executed unconditionally
603  /// - if a subexpression is executed conditionally, the first
604  /// CXXBindTemporaryExpr we encounter in that subexpression (which
605  /// corresponds to the last temporary destructor we have to call for this
606  /// subexpression) and the CFG block at that point (which will become the
607  /// successor block when inserting the decision point).
608  ///
609  /// That way, we can build the branch structure for temporary destructors as
610  /// follows:
611  /// 1. If a subexpression is executed unconditionally, we add the temporary
612  /// destructor calls to the current block.
613  /// 2. If a subexpression is executed conditionally, when we encounter a
614  /// CXXBindTemporaryExpr:
615  /// a) If it is the first temporary destructor call in the subexpression,
616  /// we remember the CXXBindTemporaryExpr and the current block in the
617  /// TempDtorContext; we start a new block, and insert the temporary
618  /// destructor call.
619  /// b) Otherwise, add the temporary destructor call to the current block.
620  /// 3. When we finished visiting a conditionally executed subexpression,
621  /// and we found at least one temporary constructor during the visitation
622  /// (2.a has executed), we insert a decision block that uses the
623  /// CXXBindTemporaryExpr as terminator, and branches to the current block
624  /// if the CXXBindTemporaryExpr was marked executed, and otherwise
625  /// branches to the stored successor.
626  struct TempDtorContext {
627  TempDtorContext() = default;
628  TempDtorContext(TryResult KnownExecuted)
629  : IsConditional(true), KnownExecuted(KnownExecuted) {}
630 
631  /// Returns whether we need to start a new branch for a temporary destructor
632  /// call. This is the case when the temporary destructor is
633  /// conditionally executed, and it is the first one we encounter while
634  /// visiting a subexpression - other temporary destructors at the same level
635  /// will be added to the same block and are executed under the same
636  /// condition.
637  bool needsTempDtorBranch() const {
638  return IsConditional && !TerminatorExpr;
639  }
640 
641  /// Remember the successor S of a temporary destructor decision branch for
642  /// the corresponding CXXBindTemporaryExpr E.
643  void setDecisionPoint(CFGBlock *S, CXXBindTemporaryExpr *E) {
644  Succ = S;
645  TerminatorExpr = E;
646  }
647 
648  const bool IsConditional = false;
649  const TryResult KnownExecuted = true;
650  CFGBlock *Succ = nullptr;
651  CXXBindTemporaryExpr *TerminatorExpr = nullptr;
652  };
653 
654  // Visitors to walk an AST and generate destructors of temporaries in
655  // full expression.
656  CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary,
657  TempDtorContext &Context);
658  CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E, TempDtorContext &Context);
659  CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E,
660  TempDtorContext &Context);
661  CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(
662  CXXBindTemporaryExpr *E, bool BindToTemporary, TempDtorContext &Context);
663  CFGBlock *VisitConditionalOperatorForTemporaryDtors(
664  AbstractConditionalOperator *E, bool BindToTemporary,
665  TempDtorContext &Context);
666  void InsertTempDtorDecisionBlock(const TempDtorContext &Context,
667  CFGBlock *FalseSucc = nullptr);
668 
669  // NYS == Not Yet Supported
670  CFGBlock *NYS() {
671  badCFG = true;
672  return Block;
673  }
674 
675  // Remember to apply the construction context based on the current \p Layer
676  // when constructing the CFG element for \p CE.
677  void consumeConstructionContext(const ConstructionContextLayer *Layer,
678  Expr *E);
679 
680  // Scan \p Child statement to find constructors in it, while keeping in mind
681  // that its parent statement is providing a partial construction context
682  // described by \p Layer. If a constructor is found, it would be assigned
683  // the context based on the layer. If an additional construction context layer
684  // is found, the function recurses into that.
685  void findConstructionContexts(const ConstructionContextLayer *Layer,
686  Stmt *Child);
687 
688  // Scan all arguments of a call expression for a construction context.
689  // These sorts of call expressions don't have a common superclass,
690  // hence strict duck-typing.
691  template <typename CallLikeExpr,
692  typename = typename std::enable_if<
693  std::is_same<CallLikeExpr, CallExpr>::value ||
694  std::is_same<CallLikeExpr, CXXConstructExpr>::value ||
695  std::is_same<CallLikeExpr, ObjCMessageExpr>::value>>
696  void findConstructionContextsForArguments(CallLikeExpr *E) {
697  for (unsigned i = 0, e = E->getNumArgs(); i != e; ++i) {
698  Expr *Arg = E->getArg(i);
699  if (Arg->getType()->getAsCXXRecordDecl() && !Arg->isGLValue())
700  findConstructionContexts(
701  ConstructionContextLayer::create(cfg->getBumpVectorContext(),
703  Arg);
704  }
705  }
706 
707  // Unset the construction context after consuming it. This is done immediately
708  // after adding the CFGConstructor or CFGCXXRecordTypedCall element, so
709  // there's no need to do this manually in every Visit... function.
710  void cleanupConstructionContext(Expr *E);
711 
712  void autoCreateBlock() { if (!Block) Block = createBlock(); }
713  CFGBlock *createBlock(bool add_successor = true);
714  CFGBlock *createNoReturnBlock();
715 
716  CFGBlock *addStmt(Stmt *S) {
717  return Visit(S, AddStmtChoice::AlwaysAdd);
718  }
719 
720  CFGBlock *addInitializer(CXXCtorInitializer *I);
721  void addLoopExit(const Stmt *LoopStmt);
722  void addAutomaticObjDtors(LocalScope::const_iterator B,
723  LocalScope::const_iterator E, Stmt *S);
724  void addLifetimeEnds(LocalScope::const_iterator B,
725  LocalScope::const_iterator E, Stmt *S);
726  void addAutomaticObjHandling(LocalScope::const_iterator B,
727  LocalScope::const_iterator E, Stmt *S);
728  void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD);
729  void addScopesEnd(LocalScope::const_iterator B, LocalScope::const_iterator E,
730  Stmt *S);
731 
732  void getDeclsWithEndedScope(LocalScope::const_iterator B,
733  LocalScope::const_iterator E, Stmt *S);
734 
735  // Local scopes creation.
736  LocalScope* createOrReuseLocalScope(LocalScope* Scope);
737 
738  void addLocalScopeForStmt(Stmt *S);
739  LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS,
740  LocalScope* Scope = nullptr);
741  LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = nullptr);
742 
743  void addLocalScopeAndDtors(Stmt *S);
744 
745  const ConstructionContext *retrieveAndCleanupConstructionContext(Expr *E) {
746  if (!BuildOpts.AddRichCXXConstructors)
747  return nullptr;
748 
749  const ConstructionContextLayer *Layer = ConstructionContextMap.lookup(E);
750  if (!Layer)
751  return nullptr;
752 
753  cleanupConstructionContext(E);
754  return ConstructionContext::createFromLayers(cfg->getBumpVectorContext(),
755  Layer);
756  }
757 
758  // Interface to CFGBlock - adding CFGElements.
759 
760  void appendStmt(CFGBlock *B, const Stmt *S) {
761  if (alwaysAdd(S) && cachedEntry)
762  cachedEntry->second = B;
763 
764  // All block-level expressions should have already been IgnoreParens()ed.
765  assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S);
766  B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext());
767  }
768 
769  void appendConstructor(CFGBlock *B, CXXConstructExpr *CE) {
770  if (const ConstructionContext *CC =
771  retrieveAndCleanupConstructionContext(CE)) {
772  B->appendConstructor(CE, CC, cfg->getBumpVectorContext());
773  return;
774  }
775 
776  // No valid construction context found. Fall back to statement.
777  B->appendStmt(CE, cfg->getBumpVectorContext());
778  }
779 
780  void appendCall(CFGBlock *B, CallExpr *CE) {
781  if (alwaysAdd(CE) && cachedEntry)
782  cachedEntry->second = B;
783 
784  if (const ConstructionContext *CC =
785  retrieveAndCleanupConstructionContext(CE)) {
786  B->appendCXXRecordTypedCall(CE, CC, cfg->getBumpVectorContext());
787  return;
788  }
789 
790  // No valid construction context found. Fall back to statement.
791  B->appendStmt(CE, cfg->getBumpVectorContext());
792  }
793 
794  void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) {
795  B->appendInitializer(I, cfg->getBumpVectorContext());
796  }
797 
798  void appendNewAllocator(CFGBlock *B, CXXNewExpr *NE) {
799  B->appendNewAllocator(NE, cfg->getBumpVectorContext());
800  }
801 
802  void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) {
803  B->appendBaseDtor(BS, cfg->getBumpVectorContext());
804  }
805 
806  void appendMemberDtor(CFGBlock *B, FieldDecl *FD) {
807  B->appendMemberDtor(FD, cfg->getBumpVectorContext());
808  }
809 
810  void appendObjCMessage(CFGBlock *B, ObjCMessageExpr *ME) {
811  if (alwaysAdd(ME) && cachedEntry)
812  cachedEntry->second = B;
813 
814  if (const ConstructionContext *CC =
815  retrieveAndCleanupConstructionContext(ME)) {
816  B->appendCXXRecordTypedCall(ME, CC, cfg->getBumpVectorContext());
817  return;
818  }
819 
820  B->appendStmt(const_cast<ObjCMessageExpr *>(ME),
821  cfg->getBumpVectorContext());
822  }
823 
824  void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) {
825  B->appendTemporaryDtor(E, cfg->getBumpVectorContext());
826  }
827 
828  void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) {
829  B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext());
830  }
831 
832  void appendLifetimeEnds(CFGBlock *B, VarDecl *VD, Stmt *S) {
833  B->appendLifetimeEnds(VD, S, cfg->getBumpVectorContext());
834  }
835 
836  void appendLoopExit(CFGBlock *B, const Stmt *LoopStmt) {
837  B->appendLoopExit(LoopStmt, cfg->getBumpVectorContext());
838  }
839 
840  void appendDeleteDtor(CFGBlock *B, CXXRecordDecl *RD, CXXDeleteExpr *DE) {
841  B->appendDeleteDtor(RD, DE, cfg->getBumpVectorContext());
842  }
843 
844  void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
845  LocalScope::const_iterator B, LocalScope::const_iterator E);
846 
847  void prependAutomaticObjLifetimeWithTerminator(CFGBlock *Blk,
848  LocalScope::const_iterator B,
849  LocalScope::const_iterator E);
850 
851  const VarDecl *
852  prependAutomaticObjScopeEndWithTerminator(CFGBlock *Blk,
853  LocalScope::const_iterator B,
854  LocalScope::const_iterator E);
855 
856  void addSuccessor(CFGBlock *B, CFGBlock *S, bool IsReachable = true) {
857  B->addSuccessor(CFGBlock::AdjacentBlock(S, IsReachable),
858  cfg->getBumpVectorContext());
859  }
860 
861  /// Add a reachable successor to a block, with the alternate variant that is
862  /// unreachable.
863  void addSuccessor(CFGBlock *B, CFGBlock *ReachableBlock, CFGBlock *AltBlock) {
864  B->addSuccessor(CFGBlock::AdjacentBlock(ReachableBlock, AltBlock),
865  cfg->getBumpVectorContext());
866  }
867 
868  void appendScopeBegin(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
869  if (BuildOpts.AddScopes)
870  B->appendScopeBegin(VD, S, cfg->getBumpVectorContext());
871  }
872 
873  void prependScopeBegin(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
874  if (BuildOpts.AddScopes)
875  B->prependScopeBegin(VD, S, cfg->getBumpVectorContext());
876  }
877 
878  void appendScopeEnd(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
879  if (BuildOpts.AddScopes)
880  B->appendScopeEnd(VD, S, cfg->getBumpVectorContext());
881  }
882 
883  void prependScopeEnd(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
884  if (BuildOpts.AddScopes)
885  B->prependScopeEnd(VD, S, cfg->getBumpVectorContext());
886  }
887 
888  /// Find a relational comparison with an expression evaluating to a
889  /// boolean and a constant other than 0 and 1.
890  /// e.g. if ((x < y) == 10)
891  TryResult checkIncorrectRelationalOperator(const BinaryOperator *B) {
892  const Expr *LHSExpr = B->getLHS()->IgnoreParens();
893  const Expr *RHSExpr = B->getRHS()->IgnoreParens();
894 
895  const IntegerLiteral *IntLiteral = dyn_cast<IntegerLiteral>(LHSExpr);
896  const Expr *BoolExpr = RHSExpr;
897  bool IntFirst = true;
898  if (!IntLiteral) {
899  IntLiteral = dyn_cast<IntegerLiteral>(RHSExpr);
900  BoolExpr = LHSExpr;
901  IntFirst = false;
902  }
903 
904  if (!IntLiteral || !BoolExpr->isKnownToHaveBooleanValue())
905  return TryResult();
906 
907  llvm::APInt IntValue = IntLiteral->getValue();
908  if ((IntValue == 1) || (IntValue == 0))
909  return TryResult();
910 
911  bool IntLarger = IntLiteral->getType()->isUnsignedIntegerType() ||
912  !IntValue.isNegative();
913 
914  BinaryOperatorKind Bok = B->getOpcode();
915  if (Bok == BO_GT || Bok == BO_GE) {
916  // Always true for 10 > bool and bool > -1
917  // Always false for -1 > bool and bool > 10
918  return TryResult(IntFirst == IntLarger);
919  } else {
920  // Always true for -1 < bool and bool < 10
921  // Always false for 10 < bool and bool < -1
922  return TryResult(IntFirst != IntLarger);
923  }
924  }
925 
926  /// Find an incorrect equality comparison. Either with an expression
927  /// evaluating to a boolean and a constant other than 0 and 1.
928  /// e.g. if (!x == 10) or a bitwise and/or operation that always evaluates to
929  /// true/false e.q. (x & 8) == 4.
930  TryResult checkIncorrectEqualityOperator(const BinaryOperator *B) {
931  const Expr *LHSExpr = B->getLHS()->IgnoreParens();
932  const Expr *RHSExpr = B->getRHS()->IgnoreParens();
933 
934  const IntegerLiteral *IntLiteral = dyn_cast<IntegerLiteral>(LHSExpr);
935  const Expr *BoolExpr = RHSExpr;
936 
937  if (!IntLiteral) {
938  IntLiteral = dyn_cast<IntegerLiteral>(RHSExpr);
939  BoolExpr = LHSExpr;
940  }
941 
942  if (!IntLiteral)
943  return TryResult();
944 
945  const BinaryOperator *BitOp = dyn_cast<BinaryOperator>(BoolExpr);
946  if (BitOp && (BitOp->getOpcode() == BO_And ||
947  BitOp->getOpcode() == BO_Or)) {
948  const Expr *LHSExpr2 = BitOp->getLHS()->IgnoreParens();
949  const Expr *RHSExpr2 = BitOp->getRHS()->IgnoreParens();
950 
951  const IntegerLiteral *IntLiteral2 = dyn_cast<IntegerLiteral>(LHSExpr2);
952 
953  if (!IntLiteral2)
954  IntLiteral2 = dyn_cast<IntegerLiteral>(RHSExpr2);
955 
956  if (!IntLiteral2)
957  return TryResult();
958 
959  llvm::APInt L1 = IntLiteral->getValue();
960  llvm::APInt L2 = IntLiteral2->getValue();
961  if ((BitOp->getOpcode() == BO_And && (L2 & L1) != L1) ||
962  (BitOp->getOpcode() == BO_Or && (L2 | L1) != L1)) {
963  if (BuildOpts.Observer)
964  BuildOpts.Observer->compareBitwiseEquality(B,
965  B->getOpcode() != BO_EQ);
966  TryResult(B->getOpcode() != BO_EQ);
967  }
968  } else if (BoolExpr->isKnownToHaveBooleanValue()) {
969  llvm::APInt IntValue = IntLiteral->getValue();
970  if ((IntValue == 1) || (IntValue == 0)) {
971  return TryResult();
972  }
973  return TryResult(B->getOpcode() != BO_EQ);
974  }
975 
976  return TryResult();
977  }
978 
979  TryResult analyzeLogicOperatorCondition(BinaryOperatorKind Relation,
980  const llvm::APSInt &Value1,
981  const llvm::APSInt &Value2) {
982  assert(Value1.isSigned() == Value2.isSigned());
983  switch (Relation) {
984  default:
985  return TryResult();
986  case BO_EQ:
987  return TryResult(Value1 == Value2);
988  case BO_NE:
989  return TryResult(Value1 != Value2);
990  case BO_LT:
991  return TryResult(Value1 < Value2);
992  case BO_LE:
993  return TryResult(Value1 <= Value2);
994  case BO_GT:
995  return TryResult(Value1 > Value2);
996  case BO_GE:
997  return TryResult(Value1 >= Value2);
998  }
999  }
1000 
1001  /// Find a pair of comparison expressions with or without parentheses
1002  /// with a shared variable and constants and a logical operator between them
1003  /// that always evaluates to either true or false.
1004  /// e.g. if (x != 3 || x != 4)
1005  TryResult checkIncorrectLogicOperator(const BinaryOperator *B) {
1006  assert(B->isLogicalOp());
1007  const BinaryOperator *LHS =
1008  dyn_cast<BinaryOperator>(B->getLHS()->IgnoreParens());
1009  const BinaryOperator *RHS =
1010  dyn_cast<BinaryOperator>(B->getRHS()->IgnoreParens());
1011  if (!LHS || !RHS)
1012  return {};
1013 
1014  if (!LHS->isComparisonOp() || !RHS->isComparisonOp())
1015  return {};
1016 
1017  const DeclRefExpr *Decl1;
1018  const Expr *Expr1;
1019  BinaryOperatorKind BO1;
1020  std::tie(Decl1, BO1, Expr1) = tryNormalizeBinaryOperator(LHS);
1021 
1022  if (!Decl1 || !Expr1)
1023  return {};
1024 
1025  const DeclRefExpr *Decl2;
1026  const Expr *Expr2;
1027  BinaryOperatorKind BO2;
1028  std::tie(Decl2, BO2, Expr2) = tryNormalizeBinaryOperator(RHS);
1029 
1030  if (!Decl2 || !Expr2)
1031  return {};
1032 
1033  // Check that it is the same variable on both sides.
1034  if (Decl1->getDecl() != Decl2->getDecl())
1035  return {};
1036 
1037  // Make sure the user's intent is clear (e.g. they're comparing against two
1038  // int literals, or two things from the same enum)
1039  if (!areExprTypesCompatible(Expr1, Expr2))
1040  return {};
1041 
1042  llvm::APSInt L1, L2;
1043 
1044  if (!Expr1->EvaluateAsInt(L1, *Context) ||
1045  !Expr2->EvaluateAsInt(L2, *Context))
1046  return {};
1047 
1048  // Can't compare signed with unsigned or with different bit width.
1049  if (L1.isSigned() != L2.isSigned() || L1.getBitWidth() != L2.getBitWidth())
1050  return {};
1051 
1052  // Values that will be used to determine if result of logical
1053  // operator is always true/false
1054  const llvm::APSInt Values[] = {
1055  // Value less than both Value1 and Value2
1056  llvm::APSInt::getMinValue(L1.getBitWidth(), L1.isUnsigned()),
1057  // L1
1058  L1,
1059  // Value between Value1 and Value2
1060  ((L1 < L2) ? L1 : L2) + llvm::APSInt(llvm::APInt(L1.getBitWidth(), 1),
1061  L1.isUnsigned()),
1062  // L2
1063  L2,
1064  // Value greater than both Value1 and Value2
1065  llvm::APSInt::getMaxValue(L1.getBitWidth(), L1.isUnsigned()),
1066  };
1067 
1068  // Check whether expression is always true/false by evaluating the following
1069  // * variable x is less than the smallest literal.
1070  // * variable x is equal to the smallest literal.
1071  // * Variable x is between smallest and largest literal.
1072  // * Variable x is equal to the largest literal.
1073  // * Variable x is greater than largest literal.
1074  bool AlwaysTrue = true, AlwaysFalse = true;
1075  for (const llvm::APSInt &Value : Values) {
1076  TryResult Res1, Res2;
1077  Res1 = analyzeLogicOperatorCondition(BO1, Value, L1);
1078  Res2 = analyzeLogicOperatorCondition(BO2, Value, L2);
1079 
1080  if (!Res1.isKnown() || !Res2.isKnown())
1081  return {};
1082 
1083  if (B->getOpcode() == BO_LAnd) {
1084  AlwaysTrue &= (Res1.isTrue() && Res2.isTrue());
1085  AlwaysFalse &= !(Res1.isTrue() && Res2.isTrue());
1086  } else {
1087  AlwaysTrue &= (Res1.isTrue() || Res2.isTrue());
1088  AlwaysFalse &= !(Res1.isTrue() || Res2.isTrue());
1089  }
1090  }
1091 
1092  if (AlwaysTrue || AlwaysFalse) {
1093  if (BuildOpts.Observer)
1094  BuildOpts.Observer->compareAlwaysTrue(B, AlwaysTrue);
1095  return TryResult(AlwaysTrue);
1096  }
1097  return {};
1098  }
1099 
1100  /// Try and evaluate an expression to an integer constant.
1101  bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) {
1102  if (!BuildOpts.PruneTriviallyFalseEdges)
1103  return false;
1104  return !S->isTypeDependent() &&
1105  !S->isValueDependent() &&
1106  S->EvaluateAsRValue(outResult, *Context);
1107  }
1108 
1109  /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1
1110  /// if we can evaluate to a known value, otherwise return -1.
1111  TryResult tryEvaluateBool(Expr *S) {
1112  if (!BuildOpts.PruneTriviallyFalseEdges ||
1113  S->isTypeDependent() || S->isValueDependent())
1114  return {};
1115 
1116  if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(S)) {
1117  if (Bop->isLogicalOp()) {
1118  // Check the cache first.
1119  CachedBoolEvalsTy::iterator I = CachedBoolEvals.find(S);
1120  if (I != CachedBoolEvals.end())
1121  return I->second; // already in map;
1122 
1123  // Retrieve result at first, or the map might be updated.
1124  TryResult Result = evaluateAsBooleanConditionNoCache(S);
1125  CachedBoolEvals[S] = Result; // update or insert
1126  return Result;
1127  }
1128  else {
1129  switch (Bop->getOpcode()) {
1130  default: break;
1131  // For 'x & 0' and 'x * 0', we can determine that
1132  // the value is always false.
1133  case BO_Mul:
1134  case BO_And: {
1135  // If either operand is zero, we know the value
1136  // must be false.
1137  llvm::APSInt IntVal;
1138  if (Bop->getLHS()->EvaluateAsInt(IntVal, *Context)) {
1139  if (!IntVal.getBoolValue()) {
1140  return TryResult(false);
1141  }
1142  }
1143  if (Bop->getRHS()->EvaluateAsInt(IntVal, *Context)) {
1144  if (!IntVal.getBoolValue()) {
1145  return TryResult(false);
1146  }
1147  }
1148  }
1149  break;
1150  }
1151  }
1152  }
1153 
1154  return evaluateAsBooleanConditionNoCache(S);
1155  }
1156 
1157  /// Evaluate as boolean \param E without using the cache.
1158  TryResult evaluateAsBooleanConditionNoCache(Expr *E) {
1159  if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(E)) {
1160  if (Bop->isLogicalOp()) {
1161  TryResult LHS = tryEvaluateBool(Bop->getLHS());
1162  if (LHS.isKnown()) {
1163  // We were able to evaluate the LHS, see if we can get away with not
1164  // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
1165  if (LHS.isTrue() == (Bop->getOpcode() == BO_LOr))
1166  return LHS.isTrue();
1167 
1168  TryResult RHS = tryEvaluateBool(Bop->getRHS());
1169  if (RHS.isKnown()) {
1170  if (Bop->getOpcode() == BO_LOr)
1171  return LHS.isTrue() || RHS.isTrue();
1172  else
1173  return LHS.isTrue() && RHS.isTrue();
1174  }
1175  } else {
1176  TryResult RHS = tryEvaluateBool(Bop->getRHS());
1177  if (RHS.isKnown()) {
1178  // We can't evaluate the LHS; however, sometimes the result
1179  // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
1180  if (RHS.isTrue() == (Bop->getOpcode() == BO_LOr))
1181  return RHS.isTrue();
1182  } else {
1183  TryResult BopRes = checkIncorrectLogicOperator(Bop);
1184  if (BopRes.isKnown())
1185  return BopRes.isTrue();
1186  }
1187  }
1188 
1189  return {};
1190  } else if (Bop->isEqualityOp()) {
1191  TryResult BopRes = checkIncorrectEqualityOperator(Bop);
1192  if (BopRes.isKnown())
1193  return BopRes.isTrue();
1194  } else if (Bop->isRelationalOp()) {
1195  TryResult BopRes = checkIncorrectRelationalOperator(Bop);
1196  if (BopRes.isKnown())
1197  return BopRes.isTrue();
1198  }
1199  }
1200 
1201  bool Result;
1202  if (E->EvaluateAsBooleanCondition(Result, *Context))
1203  return Result;
1204 
1205  return {};
1206  }
1207 
1208  bool hasTrivialDestructor(VarDecl *VD);
1209 };
1210 
1211 } // namespace
1212 
1213 inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder,
1214  const Stmt *stmt) const {
1215  return builder.alwaysAdd(stmt) || kind == AlwaysAdd;
1216 }
1217 
1218 bool CFGBuilder::alwaysAdd(const Stmt *stmt) {
1219  bool shouldAdd = BuildOpts.alwaysAdd(stmt);
1220 
1221  if (!BuildOpts.forcedBlkExprs)
1222  return shouldAdd;
1223 
1224  if (lastLookup == stmt) {
1225  if (cachedEntry) {
1226  assert(cachedEntry->first == stmt);
1227  return true;
1228  }
1229  return shouldAdd;
1230  }
1231 
1232  lastLookup = stmt;
1233 
1234  // Perform the lookup!
1235  CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs;
1236 
1237  if (!fb) {
1238  // No need to update 'cachedEntry', since it will always be null.
1239  assert(!cachedEntry);
1240  return shouldAdd;
1241  }
1242 
1243  CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt);
1244  if (itr == fb->end()) {
1245  cachedEntry = nullptr;
1246  return shouldAdd;
1247  }
1248 
1249  cachedEntry = &*itr;
1250  return true;
1251 }
1252 
1253 // FIXME: Add support for dependent-sized array types in C++?
1254 // Does it even make sense to build a CFG for an uninstantiated template?
1255 static const VariableArrayType *FindVA(const Type *t) {
1256  while (const ArrayType *vt = dyn_cast<ArrayType>(t)) {
1257  if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt))
1258  if (vat->getSizeExpr())
1259  return vat;
1260 
1261  t = vt->getElementType().getTypePtr();
1262  }
1263 
1264  return nullptr;
1265 }
1266 
1267 void CFGBuilder::consumeConstructionContext(
1268  const ConstructionContextLayer *Layer, Expr *E) {
1269  assert((isa<CXXConstructExpr>(E) || isa<CallExpr>(E) ||
1270  isa<ObjCMessageExpr>(E)) && "Expression cannot construct an object!");
1271  if (const ConstructionContextLayer *PreviouslyStoredLayer =
1272  ConstructionContextMap.lookup(E)) {
1273  (void)PreviouslyStoredLayer;
1274  // We might have visited this child when we were finding construction
1275  // contexts within its parents.
1276  assert(PreviouslyStoredLayer->isStrictlyMoreSpecificThan(Layer) &&
1277  "Already within a different construction context!");
1278  } else {
1279  ConstructionContextMap[E] = Layer;
1280  }
1281 }
1282 
1283 void CFGBuilder::findConstructionContexts(
1284  const ConstructionContextLayer *Layer, Stmt *Child) {
1285  if (!BuildOpts.AddRichCXXConstructors)
1286  return;
1287 
1288  if (!Child)
1289  return;
1290 
1291  auto withExtraLayer = [this, Layer](const ConstructionContextItem &Item) {
1292  return ConstructionContextLayer::create(cfg->getBumpVectorContext(), Item,
1293  Layer);
1294  };
1295 
1296  switch(Child->getStmtClass()) {
1297  case Stmt::CXXConstructExprClass:
1298  case Stmt::CXXTemporaryObjectExprClass: {
1299  // Support pre-C++17 copy elision AST.
1300  auto *CE = cast<CXXConstructExpr>(Child);
1301  if (BuildOpts.MarkElidedCXXConstructors && CE->isElidable()) {
1302  findConstructionContexts(withExtraLayer(CE), CE->getArg(0));
1303  }
1304 
1305  consumeConstructionContext(Layer, CE);
1306  break;
1307  }
1308  // FIXME: This, like the main visit, doesn't support CUDAKernelCallExpr.
1309  // FIXME: An isa<> would look much better but this whole switch is a
1310  // workaround for an internal compiler error in MSVC 2015 (see r326021).
1311  case Stmt::CallExprClass:
1312  case Stmt::CXXMemberCallExprClass:
1313  case Stmt::CXXOperatorCallExprClass:
1314  case Stmt::UserDefinedLiteralClass:
1315  case Stmt::ObjCMessageExprClass: {
1316  auto *E = cast<Expr>(Child);
1318  consumeConstructionContext(Layer, E);
1319  break;
1320  }
1321  case Stmt::ExprWithCleanupsClass: {
1322  auto *Cleanups = cast<ExprWithCleanups>(Child);
1323  findConstructionContexts(Layer, Cleanups->getSubExpr());
1324  break;
1325  }
1326  case Stmt::CXXFunctionalCastExprClass: {
1327  auto *Cast = cast<CXXFunctionalCastExpr>(Child);
1328  findConstructionContexts(Layer, Cast->getSubExpr());
1329  break;
1330  }
1331  case Stmt::ImplicitCastExprClass: {
1332  auto *Cast = cast<ImplicitCastExpr>(Child);
1333  // Should we support other implicit cast kinds?
1334  switch (Cast->getCastKind()) {
1335  case CK_NoOp:
1336  case CK_ConstructorConversion:
1337  findConstructionContexts(Layer, Cast->getSubExpr());
1338  break;
1339  default:
1340  break;
1341  }
1342  break;
1343  }
1344  case Stmt::CXXBindTemporaryExprClass: {
1345  auto *BTE = cast<CXXBindTemporaryExpr>(Child);
1346  findConstructionContexts(withExtraLayer(BTE), BTE->getSubExpr());
1347  break;
1348  }
1349  case Stmt::MaterializeTemporaryExprClass: {
1350  // Normally we don't want to search in MaterializeTemporaryExpr because
1351  // it indicates the beginning of a temporary object construction context,
1352  // so it shouldn't be found in the middle. However, if it is the beginning
1353  // of an elidable copy or move construction context, we need to include it.
1354  if (Layer->getItem().getKind() ==
1356  auto *MTE = cast<MaterializeTemporaryExpr>(Child);
1357  findConstructionContexts(withExtraLayer(MTE), MTE->GetTemporaryExpr());
1358  }
1359  break;
1360  }
1361  case Stmt::ConditionalOperatorClass: {
1362  auto *CO = cast<ConditionalOperator>(Child);
1363  if (Layer->getItem().getKind() !=
1365  // If the object returned by the conditional operator is not going to be a
1366  // temporary object that needs to be immediately materialized, then
1367  // it must be C++17 with its mandatory copy elision. Do not yet promise
1368  // to support this case.
1369  assert(!CO->getType()->getAsCXXRecordDecl() || CO->isGLValue() ||
1370  Context->getLangOpts().CPlusPlus17);
1371  break;
1372  }
1373  findConstructionContexts(Layer, CO->getLHS());
1374  findConstructionContexts(Layer, CO->getRHS());
1375  break;
1376  }
1377  default:
1378  break;
1379  }
1380 }
1381 
1382 void CFGBuilder::cleanupConstructionContext(Expr *E) {
1383  assert(BuildOpts.AddRichCXXConstructors &&
1384  "We should not be managing construction contexts!");
1385  assert(ConstructionContextMap.count(E) &&
1386  "Cannot exit construction context without the context!");
1387  ConstructionContextMap.erase(E);
1388 }
1389 
1390 
1391 /// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an
1392 /// arbitrary statement. Examples include a single expression or a function
1393 /// body (compound statement). The ownership of the returned CFG is
1394 /// transferred to the caller. If CFG construction fails, this method returns
1395 /// NULL.
1396 std::unique_ptr<CFG> CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) {
1397  assert(cfg.get());
1398  if (!Statement)
1399  return nullptr;
1400 
1401  // Create an empty block that will serve as the exit block for the CFG. Since
1402  // this is the first block added to the CFG, it will be implicitly registered
1403  // as the exit block.
1404  Succ = createBlock();
1405  assert(Succ == &cfg->getExit());
1406  Block = nullptr; // the EXIT block is empty. Create all other blocks lazily.
1407 
1408  assert(!(BuildOpts.AddImplicitDtors && BuildOpts.AddLifetime) &&
1409  "AddImplicitDtors and AddLifetime cannot be used at the same time");
1410 
1411  if (BuildOpts.AddImplicitDtors)
1412  if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D))
1413  addImplicitDtorsForDestructor(DD);
1414 
1415  // Visit the statements and create the CFG.
1416  CFGBlock *B = addStmt(Statement);
1417 
1418  if (badCFG)
1419  return nullptr;
1420 
1421  // For C++ constructor add initializers to CFG.
1422  if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) {
1423  for (auto *I : llvm::reverse(CD->inits())) {
1424  B = addInitializer(I);
1425  if (badCFG)
1426  return nullptr;
1427  }
1428  }
1429 
1430  if (B)
1431  Succ = B;
1432 
1433  // Backpatch the gotos whose label -> block mappings we didn't know when we
1434  // encountered them.
1435  for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(),
1436  E = BackpatchBlocks.end(); I != E; ++I ) {
1437 
1438  CFGBlock *B = I->block;
1439  const GotoStmt *G = cast<GotoStmt>(B->getTerminator());
1440  LabelMapTy::iterator LI = LabelMap.find(G->getLabel());
1441 
1442  // If there is no target for the goto, then we are looking at an
1443  // incomplete AST. Handle this by not registering a successor.
1444  if (LI == LabelMap.end()) continue;
1445 
1446  JumpTarget JT = LI->second;
1447  prependAutomaticObjLifetimeWithTerminator(B, I->scopePosition,
1448  JT.scopePosition);
1449  prependAutomaticObjDtorsWithTerminator(B, I->scopePosition,
1450  JT.scopePosition);
1451  const VarDecl *VD = prependAutomaticObjScopeEndWithTerminator(
1452  B, I->scopePosition, JT.scopePosition);
1453  appendScopeBegin(JT.block, VD, G);
1454  addSuccessor(B, JT.block);
1455  }
1456 
1457  // Add successors to the Indirect Goto Dispatch block (if we have one).
1458  if (CFGBlock *B = cfg->getIndirectGotoBlock())
1459  for (LabelSetTy::iterator I = AddressTakenLabels.begin(),
1460  E = AddressTakenLabels.end(); I != E; ++I ) {
1461  // Lookup the target block.
1462  LabelMapTy::iterator LI = LabelMap.find(*I);
1463 
1464  // If there is no target block that contains label, then we are looking
1465  // at an incomplete AST. Handle this by not registering a successor.
1466  if (LI == LabelMap.end()) continue;
1467 
1468  addSuccessor(B, LI->second.block);
1469  }
1470 
1471  // Create an empty entry block that has no predecessors.
1472  cfg->setEntry(createBlock());
1473 
1474  if (BuildOpts.AddRichCXXConstructors)
1475  assert(ConstructionContextMap.empty() &&
1476  "Not all construction contexts were cleaned up!");
1477 
1478  return std::move(cfg);
1479 }
1480 
1481 /// createBlock - Used to lazily create blocks that are connected
1482 /// to the current (global) succcessor.
1483 CFGBlock *CFGBuilder::createBlock(bool add_successor) {
1484  CFGBlock *B = cfg->createBlock();
1485  if (add_successor && Succ)
1486  addSuccessor(B, Succ);
1487  return B;
1488 }
1489 
1490 /// createNoReturnBlock - Used to create a block is a 'noreturn' point in the
1491 /// CFG. It is *not* connected to the current (global) successor, and instead
1492 /// directly tied to the exit block in order to be reachable.
1493 CFGBlock *CFGBuilder::createNoReturnBlock() {
1494  CFGBlock *B = createBlock(false);
1495  B->setHasNoReturnElement();
1496  addSuccessor(B, &cfg->getExit(), Succ);
1497  return B;
1498 }
1499 
1500 /// addInitializer - Add C++ base or member initializer element to CFG.
1501 CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) {
1502  if (!BuildOpts.AddInitializers)
1503  return Block;
1504 
1505  bool HasTemporaries = false;
1506 
1507  // Destructors of temporaries in initialization expression should be called
1508  // after initialization finishes.
1509  Expr *Init = I->getInit();
1510  if (Init) {
1511  HasTemporaries = isa<ExprWithCleanups>(Init);
1512 
1513  if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
1514  // Generate destructors for temporaries in initialization expression.
1515  TempDtorContext Context;
1516  VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
1517  /*BindToTemporary=*/false, Context);
1518  }
1519  }
1520 
1521  autoCreateBlock();
1522  appendInitializer(Block, I);
1523 
1524  if (Init) {
1525  findConstructionContexts(
1526  ConstructionContextLayer::create(cfg->getBumpVectorContext(), I),
1527  Init);
1528 
1529  if (HasTemporaries) {
1530  // For expression with temporaries go directly to subexpression to omit
1531  // generating destructors for the second time.
1532  return Visit(cast<ExprWithCleanups>(Init)->getSubExpr());
1533  }
1534  if (BuildOpts.AddCXXDefaultInitExprInCtors) {
1535  if (CXXDefaultInitExpr *Default = dyn_cast<CXXDefaultInitExpr>(Init)) {
1536  // In general, appending the expression wrapped by a CXXDefaultInitExpr
1537  // may cause the same Expr to appear more than once in the CFG. Doing it
1538  // here is safe because there's only one initializer per field.
1539  autoCreateBlock();
1540  appendStmt(Block, Default);
1541  if (Stmt *Child = Default->getExpr())
1542  if (CFGBlock *R = Visit(Child))
1543  Block = R;
1544  return Block;
1545  }
1546  }
1547  return Visit(Init);
1548  }
1549 
1550  return Block;
1551 }
1552 
1553 /// Retrieve the type of the temporary object whose lifetime was
1554 /// extended by a local reference with the given initializer.
1556  bool *FoundMTE = nullptr) {
1557  while (true) {
1558  // Skip parentheses.
1559  Init = Init->IgnoreParens();
1560 
1561  // Skip through cleanups.
1562  if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Init)) {
1563  Init = EWC->getSubExpr();
1564  continue;
1565  }
1566 
1567  // Skip through the temporary-materialization expression.
1568  if (const MaterializeTemporaryExpr *MTE
1569  = dyn_cast<MaterializeTemporaryExpr>(Init)) {
1570  Init = MTE->GetTemporaryExpr();
1571  if (FoundMTE)
1572  *FoundMTE = true;
1573  continue;
1574  }
1575 
1576  // Skip sub-object accesses into rvalues.
1577  SmallVector<const Expr *, 2> CommaLHSs;
1579  const Expr *SkippedInit =
1580  Init->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
1581  if (SkippedInit != Init) {
1582  Init = SkippedInit;
1583  continue;
1584  }
1585 
1586  break;
1587  }
1588 
1589  return Init->getType();
1590 }
1591 
1592 // TODO: Support adding LoopExit element to the CFG in case where the loop is
1593 // ended by ReturnStmt, GotoStmt or ThrowExpr.
1594 void CFGBuilder::addLoopExit(const Stmt *LoopStmt){
1595  if(!BuildOpts.AddLoopExit)
1596  return;
1597  autoCreateBlock();
1598  appendLoopExit(Block, LoopStmt);
1599 }
1600 
1601 void CFGBuilder::getDeclsWithEndedScope(LocalScope::const_iterator B,
1602  LocalScope::const_iterator E, Stmt *S) {
1603  if (!BuildOpts.AddScopes)
1604  return;
1605 
1606  if (B == E)
1607  return;
1608 
1609  // To go from B to E, one first goes up the scopes from B to P
1610  // then sideways in one scope from P to P' and then down
1611  // the scopes from P' to E.
1612  // The lifetime of all objects between B and P end.
1613  LocalScope::const_iterator P = B.shared_parent(E);
1614  int Dist = B.distance(P);
1615  if (Dist <= 0)
1616  return;
1617 
1618  for (LocalScope::const_iterator I = B; I != P; ++I)
1619  if (I.pointsToFirstDeclaredVar())
1620  DeclsWithEndedScope.insert(*I);
1621 }
1622 
1623 void CFGBuilder::addAutomaticObjHandling(LocalScope::const_iterator B,
1624  LocalScope::const_iterator E,
1625  Stmt *S) {
1626  getDeclsWithEndedScope(B, E, S);
1627  if (BuildOpts.AddScopes)
1628  addScopesEnd(B, E, S);
1629  if (BuildOpts.AddImplicitDtors)
1630  addAutomaticObjDtors(B, E, S);
1631  if (BuildOpts.AddLifetime)
1632  addLifetimeEnds(B, E, S);
1633 }
1634 
1635 /// Add to current block automatic objects that leave the scope.
1636 void CFGBuilder::addLifetimeEnds(LocalScope::const_iterator B,
1637  LocalScope::const_iterator E, Stmt *S) {
1638  if (!BuildOpts.AddLifetime)
1639  return;
1640 
1641  if (B == E)
1642  return;
1643 
1644  // To go from B to E, one first goes up the scopes from B to P
1645  // then sideways in one scope from P to P' and then down
1646  // the scopes from P' to E.
1647  // The lifetime of all objects between B and P end.
1648  LocalScope::const_iterator P = B.shared_parent(E);
1649  int dist = B.distance(P);
1650  if (dist <= 0)
1651  return;
1652 
1653  // We need to perform the scope leaving in reverse order
1654  SmallVector<VarDecl *, 10> DeclsTrivial;
1655  SmallVector<VarDecl *, 10> DeclsNonTrivial;
1656  DeclsTrivial.reserve(dist);
1657  DeclsNonTrivial.reserve(dist);
1658 
1659  for (LocalScope::const_iterator I = B; I != P; ++I)
1660  if (hasTrivialDestructor(*I))
1661  DeclsTrivial.push_back(*I);
1662  else
1663  DeclsNonTrivial.push_back(*I);
1664 
1665  autoCreateBlock();
1666  // object with trivial destructor end their lifetime last (when storage
1667  // duration ends)
1668  for (SmallVectorImpl<VarDecl *>::reverse_iterator I = DeclsTrivial.rbegin(),
1669  E = DeclsTrivial.rend();
1670  I != E; ++I)
1671  appendLifetimeEnds(Block, *I, S);
1672 
1674  I = DeclsNonTrivial.rbegin(),
1675  E = DeclsNonTrivial.rend();
1676  I != E; ++I)
1677  appendLifetimeEnds(Block, *I, S);
1678 }
1679 
1680 /// Add to current block markers for ending scopes.
1681 void CFGBuilder::addScopesEnd(LocalScope::const_iterator B,
1682  LocalScope::const_iterator E, Stmt *S) {
1683  // If implicit destructors are enabled, we'll add scope ends in
1684  // addAutomaticObjDtors.
1685  if (BuildOpts.AddImplicitDtors)
1686  return;
1687 
1688  autoCreateBlock();
1689 
1690  for (auto I = DeclsWithEndedScope.rbegin(), E = DeclsWithEndedScope.rend();
1691  I != E; ++I)
1692  appendScopeEnd(Block, *I, S);
1693 
1694  return;
1695 }
1696 
1697 /// addAutomaticObjDtors - Add to current block automatic objects destructors
1698 /// for objects in range of local scope positions. Use S as trigger statement
1699 /// for destructors.
1700 void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B,
1701  LocalScope::const_iterator E, Stmt *S) {
1702  if (!BuildOpts.AddImplicitDtors)
1703  return;
1704 
1705  if (B == E)
1706  return;
1707 
1708  // We need to append the destructors in reverse order, but any one of them
1709  // may be a no-return destructor which changes the CFG. As a result, buffer
1710  // this sequence up and replay them in reverse order when appending onto the
1711  // CFGBlock(s).
1713  Decls.reserve(B.distance(E));
1714  for (LocalScope::const_iterator I = B; I != E; ++I)
1715  Decls.push_back(*I);
1716 
1717  for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(),
1718  E = Decls.rend();
1719  I != E; ++I) {
1720  if (hasTrivialDestructor(*I)) {
1721  // If AddScopes is enabled and *I is a first variable in a scope, add a
1722  // ScopeEnd marker in a Block.
1723  if (BuildOpts.AddScopes && DeclsWithEndedScope.count(*I)) {
1724  autoCreateBlock();
1725  appendScopeEnd(Block, *I, S);
1726  }
1727  continue;
1728  }
1729  // If this destructor is marked as a no-return destructor, we need to
1730  // create a new block for the destructor which does not have as a successor
1731  // anything built thus far: control won't flow out of this block.
1732  QualType Ty = (*I)->getType();
1733  if (Ty->isReferenceType()) {
1734  Ty = getReferenceInitTemporaryType((*I)->getInit());
1735  }
1736  Ty = Context->getBaseElementType(Ty);
1737 
1738  if (Ty->getAsCXXRecordDecl()->isAnyDestructorNoReturn())
1739  Block = createNoReturnBlock();
1740  else
1741  autoCreateBlock();
1742 
1743  // Add ScopeEnd just after automatic obj destructor.
1744  if (BuildOpts.AddScopes && DeclsWithEndedScope.count(*I))
1745  appendScopeEnd(Block, *I, S);
1746  appendAutomaticObjDtor(Block, *I, S);
1747  }
1748 }
1749 
1750 /// addImplicitDtorsForDestructor - Add implicit destructors generated for
1751 /// base and member objects in destructor.
1752 void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) {
1753  assert(BuildOpts.AddImplicitDtors &&
1754  "Can be called only when dtors should be added");
1755  const CXXRecordDecl *RD = DD->getParent();
1756 
1757  // At the end destroy virtual base objects.
1758  for (const auto &VI : RD->vbases()) {
1759  const CXXRecordDecl *CD = VI.getType()->getAsCXXRecordDecl();
1760  if (!CD->hasTrivialDestructor()) {
1761  autoCreateBlock();
1762  appendBaseDtor(Block, &VI);
1763  }
1764  }
1765 
1766  // Before virtual bases destroy direct base objects.
1767  for (const auto &BI : RD->bases()) {
1768  if (!BI.isVirtual()) {
1769  const CXXRecordDecl *CD = BI.getType()->getAsCXXRecordDecl();
1770  if (!CD->hasTrivialDestructor()) {
1771  autoCreateBlock();
1772  appendBaseDtor(Block, &BI);
1773  }
1774  }
1775  }
1776 
1777  // First destroy member objects.
1778  for (auto *FI : RD->fields()) {
1779  // Check for constant size array. Set type to array element type.
1780  QualType QT = FI->getType();
1781  if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
1782  if (AT->getSize() == 0)
1783  continue;
1784  QT = AT->getElementType();
1785  }
1786 
1787  if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
1788  if (!CD->hasTrivialDestructor()) {
1789  autoCreateBlock();
1790  appendMemberDtor(Block, FI);
1791  }
1792  }
1793 }
1794 
1795 /// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either
1796 /// way return valid LocalScope object.
1797 LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) {
1798  if (Scope)
1799  return Scope;
1800  llvm::BumpPtrAllocator &alloc = cfg->getAllocator();
1801  return new (alloc.Allocate<LocalScope>())
1802  LocalScope(BumpVectorContext(alloc), ScopePos);
1803 }
1804 
1805 /// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement
1806 /// that should create implicit scope (e.g. if/else substatements).
1807 void CFGBuilder::addLocalScopeForStmt(Stmt *S) {
1808  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1809  !BuildOpts.AddScopes)
1810  return;
1811 
1812  LocalScope *Scope = nullptr;
1813 
1814  // For compound statement we will be creating explicit scope.
1815  if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
1816  for (auto *BI : CS->body()) {
1817  Stmt *SI = BI->stripLabelLikeStatements();
1818  if (DeclStmt *DS = dyn_cast<DeclStmt>(SI))
1819  Scope = addLocalScopeForDeclStmt(DS, Scope);
1820  }
1821  return;
1822  }
1823 
1824  // For any other statement scope will be implicit and as such will be
1825  // interesting only for DeclStmt.
1826  if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements()))
1827  addLocalScopeForDeclStmt(DS);
1828 }
1829 
1830 /// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will
1831 /// reuse Scope if not NULL.
1832 LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS,
1833  LocalScope* Scope) {
1834  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1835  !BuildOpts.AddScopes)
1836  return Scope;
1837 
1838  for (auto *DI : DS->decls())
1839  if (VarDecl *VD = dyn_cast<VarDecl>(DI))
1840  Scope = addLocalScopeForVarDecl(VD, Scope);
1841  return Scope;
1842 }
1843 
1844 bool CFGBuilder::hasTrivialDestructor(VarDecl *VD) {
1845  // Check for const references bound to temporary. Set type to pointee.
1846  QualType QT = VD->getType();
1847  if (QT->isReferenceType()) {
1848  // Attempt to determine whether this declaration lifetime-extends a
1849  // temporary.
1850  //
1851  // FIXME: This is incorrect. Non-reference declarations can lifetime-extend
1852  // temporaries, and a single declaration can extend multiple temporaries.
1853  // We should look at the storage duration on each nested
1854  // MaterializeTemporaryExpr instead.
1855 
1856  const Expr *Init = VD->getInit();
1857  if (!Init) {
1858  // Probably an exception catch-by-reference variable.
1859  // FIXME: It doesn't really mean that the object has a trivial destructor.
1860  // Also are there other cases?
1861  return true;
1862  }
1863 
1864  // Lifetime-extending a temporary?
1865  bool FoundMTE = false;
1866  QT = getReferenceInitTemporaryType(Init, &FoundMTE);
1867  if (!FoundMTE)
1868  return true;
1869  }
1870 
1871  // Check for constant size array. Set type to array element type.
1872  while (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
1873  if (AT->getSize() == 0)
1874  return true;
1875  QT = AT->getElementType();
1876  }
1877 
1878  // Check if type is a C++ class with non-trivial destructor.
1879  if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
1880  return !CD->hasDefinition() || CD->hasTrivialDestructor();
1881  return true;
1882 }
1883 
1884 /// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will
1885 /// create add scope for automatic objects and temporary objects bound to
1886 /// const reference. Will reuse Scope if not NULL.
1887 LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD,
1888  LocalScope* Scope) {
1889  assert(!(BuildOpts.AddImplicitDtors && BuildOpts.AddLifetime) &&
1890  "AddImplicitDtors and AddLifetime cannot be used at the same time");
1891  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1892  !BuildOpts.AddScopes)
1893  return Scope;
1894 
1895  // Check if variable is local.
1896  switch (VD->getStorageClass()) {
1897  case SC_None:
1898  case SC_Auto:
1899  case SC_Register:
1900  break;
1901  default: return Scope;
1902  }
1903 
1904  if (BuildOpts.AddImplicitDtors) {
1905  if (!hasTrivialDestructor(VD) || BuildOpts.AddScopes) {
1906  // Add the variable to scope
1907  Scope = createOrReuseLocalScope(Scope);
1908  Scope->addVar(VD);
1909  ScopePos = Scope->begin();
1910  }
1911  return Scope;
1912  }
1913 
1914  assert(BuildOpts.AddLifetime);
1915  // Add the variable to scope
1916  Scope = createOrReuseLocalScope(Scope);
1917  Scope->addVar(VD);
1918  ScopePos = Scope->begin();
1919  return Scope;
1920 }
1921 
1922 /// addLocalScopeAndDtors - For given statement add local scope for it and
1923 /// add destructors that will cleanup the scope. Will reuse Scope if not NULL.
1924 void CFGBuilder::addLocalScopeAndDtors(Stmt *S) {
1925  LocalScope::const_iterator scopeBeginPos = ScopePos;
1926  addLocalScopeForStmt(S);
1927  addAutomaticObjHandling(ScopePos, scopeBeginPos, S);
1928 }
1929 
1930 /// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for
1931 /// variables with automatic storage duration to CFGBlock's elements vector.
1932 /// Elements will be prepended to physical beginning of the vector which
1933 /// happens to be logical end. Use blocks terminator as statement that specifies
1934 /// destructors call site.
1935 /// FIXME: This mechanism for adding automatic destructors doesn't handle
1936 /// no-return destructors properly.
1937 void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
1938  LocalScope::const_iterator B, LocalScope::const_iterator E) {
1939  if (!BuildOpts.AddImplicitDtors)
1940  return;
1941  BumpVectorContext &C = cfg->getBumpVectorContext();
1942  CFGBlock::iterator InsertPos
1943  = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C);
1944  for (LocalScope::const_iterator I = B; I != E; ++I)
1945  InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I,
1946  Blk->getTerminator());
1947 }
1948 
1949 /// prependAutomaticObjLifetimeWithTerminator - Prepend lifetime CFGElements for
1950 /// variables with automatic storage duration to CFGBlock's elements vector.
1951 /// Elements will be prepended to physical beginning of the vector which
1952 /// happens to be logical end. Use blocks terminator as statement that specifies
1953 /// where lifetime ends.
1954 void CFGBuilder::prependAutomaticObjLifetimeWithTerminator(
1955  CFGBlock *Blk, LocalScope::const_iterator B, LocalScope::const_iterator E) {
1956  if (!BuildOpts.AddLifetime)
1957  return;
1958  BumpVectorContext &C = cfg->getBumpVectorContext();
1959  CFGBlock::iterator InsertPos =
1960  Blk->beginLifetimeEndsInsert(Blk->end(), B.distance(E), C);
1961  for (LocalScope::const_iterator I = B; I != E; ++I)
1962  InsertPos = Blk->insertLifetimeEnds(InsertPos, *I, Blk->getTerminator());
1963 }
1964 
1965 /// prependAutomaticObjScopeEndWithTerminator - Prepend scope end CFGElements for
1966 /// variables with automatic storage duration to CFGBlock's elements vector.
1967 /// Elements will be prepended to physical beginning of the vector which
1968 /// happens to be logical end. Use blocks terminator as statement that specifies
1969 /// where scope ends.
1970 const VarDecl *
1971 CFGBuilder::prependAutomaticObjScopeEndWithTerminator(
1972  CFGBlock *Blk, LocalScope::const_iterator B, LocalScope::const_iterator E) {
1973  if (!BuildOpts.AddScopes)
1974  return nullptr;
1975  BumpVectorContext &C = cfg->getBumpVectorContext();
1976  CFGBlock::iterator InsertPos =
1977  Blk->beginScopeEndInsert(Blk->end(), 1, C);
1978  LocalScope::const_iterator PlaceToInsert = B;
1979  for (LocalScope::const_iterator I = B; I != E; ++I)
1980  PlaceToInsert = I;
1981  Blk->insertScopeEnd(InsertPos, *PlaceToInsert, Blk->getTerminator());
1982  return *PlaceToInsert;
1983 }
1984 
1985 /// Visit - Walk the subtree of a statement and add extra
1986 /// blocks for ternary operators, &&, and ||. We also process "," and
1987 /// DeclStmts (which may contain nested control-flow).
1988 CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) {
1989  if (!S) {
1990  badCFG = true;
1991  return nullptr;
1992  }
1993 
1994  if (Expr *E = dyn_cast<Expr>(S))
1995  S = E->IgnoreParens();
1996 
1997  switch (S->getStmtClass()) {
1998  default:
1999  return VisitStmt(S, asc);
2000 
2001  case Stmt::AddrLabelExprClass:
2002  return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc);
2003 
2004  case Stmt::BinaryConditionalOperatorClass:
2005  return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc);
2006 
2007  case Stmt::BinaryOperatorClass:
2008  return VisitBinaryOperator(cast<BinaryOperator>(S), asc);
2009 
2010  case Stmt::BlockExprClass:
2011  return VisitBlockExpr(cast<BlockExpr>(S), asc);
2012 
2013  case Stmt::BreakStmtClass:
2014  return VisitBreakStmt(cast<BreakStmt>(S));
2015 
2016  case Stmt::CallExprClass:
2017  case Stmt::CXXOperatorCallExprClass:
2018  case Stmt::CXXMemberCallExprClass:
2019  case Stmt::UserDefinedLiteralClass:
2020  return VisitCallExpr(cast<CallExpr>(S), asc);
2021 
2022  case Stmt::CaseStmtClass:
2023  return VisitCaseStmt(cast<CaseStmt>(S));
2024 
2025  case Stmt::ChooseExprClass:
2026  return VisitChooseExpr(cast<ChooseExpr>(S), asc);
2027 
2028  case Stmt::CompoundStmtClass:
2029  return VisitCompoundStmt(cast<CompoundStmt>(S));
2030 
2031  case Stmt::ConditionalOperatorClass:
2032  return VisitConditionalOperator(cast<ConditionalOperator>(S), asc);
2033 
2034  case Stmt::ContinueStmtClass:
2035  return VisitContinueStmt(cast<ContinueStmt>(S));
2036 
2037  case Stmt::CXXCatchStmtClass:
2038  return VisitCXXCatchStmt(cast<CXXCatchStmt>(S));
2039 
2040  case Stmt::ExprWithCleanupsClass:
2041  return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc);
2042 
2043  case Stmt::CXXDefaultArgExprClass:
2044  case Stmt::CXXDefaultInitExprClass:
2045  // FIXME: The expression inside a CXXDefaultArgExpr is owned by the
2046  // called function's declaration, not by the caller. If we simply add
2047  // this expression to the CFG, we could end up with the same Expr
2048  // appearing multiple times.
2049  // PR13385 / <rdar://problem/12156507>
2050  //
2051  // It's likewise possible for multiple CXXDefaultInitExprs for the same
2052  // expression to be used in the same function (through aggregate
2053  // initialization).
2054  return VisitStmt(S, asc);
2055 
2056  case Stmt::CXXBindTemporaryExprClass:
2057  return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc);
2058 
2059  case Stmt::CXXConstructExprClass:
2060  return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc);
2061 
2062  case Stmt::CXXNewExprClass:
2063  return VisitCXXNewExpr(cast<CXXNewExpr>(S), asc);
2064 
2065  case Stmt::CXXDeleteExprClass:
2066  return VisitCXXDeleteExpr(cast<CXXDeleteExpr>(S), asc);
2067 
2068  case Stmt::CXXFunctionalCastExprClass:
2069  return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc);
2070 
2071  case Stmt::CXXTemporaryObjectExprClass:
2072  return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc);
2073 
2074  case Stmt::CXXThrowExprClass:
2075  return VisitCXXThrowExpr(cast<CXXThrowExpr>(S));
2076 
2077  case Stmt::CXXTryStmtClass:
2078  return VisitCXXTryStmt(cast<CXXTryStmt>(S));
2079 
2080  case Stmt::CXXForRangeStmtClass:
2081  return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S));
2082 
2083  case Stmt::DeclStmtClass:
2084  return VisitDeclStmt(cast<DeclStmt>(S));
2085 
2086  case Stmt::DefaultStmtClass:
2087  return VisitDefaultStmt(cast<DefaultStmt>(S));
2088 
2089  case Stmt::DoStmtClass:
2090  return VisitDoStmt(cast<DoStmt>(S));
2091 
2092  case Stmt::ForStmtClass:
2093  return VisitForStmt(cast<ForStmt>(S));
2094 
2095  case Stmt::GotoStmtClass:
2096  return VisitGotoStmt(cast<GotoStmt>(S));
2097 
2098  case Stmt::IfStmtClass:
2099  return VisitIfStmt(cast<IfStmt>(S));
2100 
2101  case Stmt::ImplicitCastExprClass:
2102  return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc);
2103 
2104  case Stmt::ConstantExprClass:
2105  return VisitConstantExpr(cast<ConstantExpr>(S), asc);
2106 
2107  case Stmt::IndirectGotoStmtClass:
2108  return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S));
2109 
2110  case Stmt::LabelStmtClass:
2111  return VisitLabelStmt(cast<LabelStmt>(S));
2112 
2113  case Stmt::LambdaExprClass:
2114  return VisitLambdaExpr(cast<LambdaExpr>(S), asc);
2115 
2116  case Stmt::MaterializeTemporaryExprClass:
2117  return VisitMaterializeTemporaryExpr(cast<MaterializeTemporaryExpr>(S),
2118  asc);
2119 
2120  case Stmt::MemberExprClass:
2121  return VisitMemberExpr(cast<MemberExpr>(S), asc);
2122 
2123  case Stmt::NullStmtClass:
2124  return Block;
2125 
2126  case Stmt::ObjCAtCatchStmtClass:
2127  return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S));
2128 
2129  case Stmt::ObjCAutoreleasePoolStmtClass:
2130  return VisitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(S));
2131 
2132  case Stmt::ObjCAtSynchronizedStmtClass:
2133  return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S));
2134 
2135  case Stmt::ObjCAtThrowStmtClass:
2136  return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S));
2137 
2138  case Stmt::ObjCAtTryStmtClass:
2139  return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S));
2140 
2141  case Stmt::ObjCForCollectionStmtClass:
2142  return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S));
2143 
2144  case Stmt::ObjCMessageExprClass:
2145  return VisitObjCMessageExpr(cast<ObjCMessageExpr>(S), asc);
2146 
2147  case Stmt::OpaqueValueExprClass:
2148  return Block;
2149 
2150  case Stmt::PseudoObjectExprClass:
2151  return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S));
2152 
2153  case Stmt::ReturnStmtClass:
2154  case Stmt::CoreturnStmtClass:
2155  return VisitReturnStmt(S);
2156 
2157  case Stmt::SEHExceptStmtClass:
2158  return VisitSEHExceptStmt(cast<SEHExceptStmt>(S));
2159 
2160  case Stmt::SEHFinallyStmtClass:
2161  return VisitSEHFinallyStmt(cast<SEHFinallyStmt>(S));
2162 
2163  case Stmt::SEHLeaveStmtClass:
2164  return VisitSEHLeaveStmt(cast<SEHLeaveStmt>(S));
2165 
2166  case Stmt::SEHTryStmtClass:
2167  return VisitSEHTryStmt(cast<SEHTryStmt>(S));
2168 
2169  case Stmt::UnaryExprOrTypeTraitExprClass:
2170  return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S),
2171  asc);
2172 
2173  case Stmt::StmtExprClass:
2174  return VisitStmtExpr(cast<StmtExpr>(S), asc);
2175 
2176  case Stmt::SwitchStmtClass:
2177  return VisitSwitchStmt(cast<SwitchStmt>(S));
2178 
2179  case Stmt::UnaryOperatorClass:
2180  return VisitUnaryOperator(cast<UnaryOperator>(S), asc);
2181 
2182  case Stmt::WhileStmtClass:
2183  return VisitWhileStmt(cast<WhileStmt>(S));
2184  }
2185 }
2186 
2187 CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) {
2188  if (asc.alwaysAdd(*this, S)) {
2189  autoCreateBlock();
2190  appendStmt(Block, S);
2191  }
2192 
2193  return VisitChildren(S);
2194 }
2195 
2196 /// VisitChildren - Visit the children of a Stmt.
2197 CFGBlock *CFGBuilder::VisitChildren(Stmt *S) {
2198  CFGBlock *B = Block;
2199 
2200  // Visit the children in their reverse order so that they appear in
2201  // left-to-right (natural) order in the CFG.
2202  reverse_children RChildren(S);
2203  for (reverse_children::iterator I = RChildren.begin(), E = RChildren.end();
2204  I != E; ++I) {
2205  if (Stmt *Child = *I)
2206  if (CFGBlock *R = Visit(Child))
2207  B = R;
2208  }
2209  return B;
2210 }
2211 
2212 CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A,
2213  AddStmtChoice asc) {
2214  AddressTakenLabels.insert(A->getLabel());
2215 
2216  if (asc.alwaysAdd(*this, A)) {
2217  autoCreateBlock();
2218  appendStmt(Block, A);
2219  }
2220 
2221  return Block;
2222 }
2223 
2224 CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U,
2225  AddStmtChoice asc) {
2226  if (asc.alwaysAdd(*this, U)) {
2227  autoCreateBlock();
2228  appendStmt(Block, U);
2229  }
2230 
2231  return Visit(U->getSubExpr(), AddStmtChoice());
2232 }
2233 
2234 CFGBlock *CFGBuilder::VisitLogicalOperator(BinaryOperator *B) {
2235  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2236  appendStmt(ConfluenceBlock, B);
2237 
2238  if (badCFG)
2239  return nullptr;
2240 
2241  return VisitLogicalOperator(B, nullptr, ConfluenceBlock,
2242  ConfluenceBlock).first;
2243 }
2244 
2245 std::pair<CFGBlock*, CFGBlock*>
2246 CFGBuilder::VisitLogicalOperator(BinaryOperator *B,
2247  Stmt *Term,
2248  CFGBlock *TrueBlock,
2249  CFGBlock *FalseBlock) {
2250  // Introspect the RHS. If it is a nested logical operation, we recursively
2251  // build the CFG using this function. Otherwise, resort to default
2252  // CFG construction behavior.
2253  Expr *RHS = B->getRHS()->IgnoreParens();
2254  CFGBlock *RHSBlock, *ExitBlock;
2255 
2256  do {
2257  if (BinaryOperator *B_RHS = dyn_cast<BinaryOperator>(RHS))
2258  if (B_RHS->isLogicalOp()) {
2259  std::tie(RHSBlock, ExitBlock) =
2260  VisitLogicalOperator(B_RHS, Term, TrueBlock, FalseBlock);
2261  break;
2262  }
2263 
2264  // The RHS is not a nested logical operation. Don't push the terminator
2265  // down further, but instead visit RHS and construct the respective
2266  // pieces of the CFG, and link up the RHSBlock with the terminator
2267  // we have been provided.
2268  ExitBlock = RHSBlock = createBlock(false);
2269 
2270  // Even though KnownVal is only used in the else branch of the next
2271  // conditional, tryEvaluateBool performs additional checking on the
2272  // Expr, so it should be called unconditionally.
2273  TryResult KnownVal = tryEvaluateBool(RHS);
2274  if (!KnownVal.isKnown())
2275  KnownVal = tryEvaluateBool(B);
2276 
2277  if (!Term) {
2278  assert(TrueBlock == FalseBlock);
2279  addSuccessor(RHSBlock, TrueBlock);
2280  }
2281  else {
2282  RHSBlock->setTerminator(Term);
2283  addSuccessor(RHSBlock, TrueBlock, !KnownVal.isFalse());
2284  addSuccessor(RHSBlock, FalseBlock, !KnownVal.isTrue());
2285  }
2286 
2287  Block = RHSBlock;
2288  RHSBlock = addStmt(RHS);
2289  }
2290  while (false);
2291 
2292  if (badCFG)
2293  return std::make_pair(nullptr, nullptr);
2294 
2295  // Generate the blocks for evaluating the LHS.
2296  Expr *LHS = B->getLHS()->IgnoreParens();
2297 
2298  if (BinaryOperator *B_LHS = dyn_cast<BinaryOperator>(LHS))
2299  if (B_LHS->isLogicalOp()) {
2300  if (B->getOpcode() == BO_LOr)
2301  FalseBlock = RHSBlock;
2302  else
2303  TrueBlock = RHSBlock;
2304 
2305  // For the LHS, treat 'B' as the terminator that we want to sink
2306  // into the nested branch. The RHS always gets the top-most
2307  // terminator.
2308  return VisitLogicalOperator(B_LHS, B, TrueBlock, FalseBlock);
2309  }
2310 
2311  // Create the block evaluating the LHS.
2312  // This contains the '&&' or '||' as the terminator.
2313  CFGBlock *LHSBlock = createBlock(false);
2314  LHSBlock->setTerminator(B);
2315 
2316  Block = LHSBlock;
2317  CFGBlock *EntryLHSBlock = addStmt(LHS);
2318 
2319  if (badCFG)
2320  return std::make_pair(nullptr, nullptr);
2321 
2322  // See if this is a known constant.
2323  TryResult KnownVal = tryEvaluateBool(LHS);
2324 
2325  // Now link the LHSBlock with RHSBlock.
2326  if (B->getOpcode() == BO_LOr) {
2327  addSuccessor(LHSBlock, TrueBlock, !KnownVal.isFalse());
2328  addSuccessor(LHSBlock, RHSBlock, !KnownVal.isTrue());
2329  } else {
2330  assert(B->getOpcode() == BO_LAnd);
2331  addSuccessor(LHSBlock, RHSBlock, !KnownVal.isFalse());
2332  addSuccessor(LHSBlock, FalseBlock, !KnownVal.isTrue());
2333  }
2334 
2335  return std::make_pair(EntryLHSBlock, ExitBlock);
2336 }
2337 
2338 CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B,
2339  AddStmtChoice asc) {
2340  // && or ||
2341  if (B->isLogicalOp())
2342  return VisitLogicalOperator(B);
2343 
2344  if (B->getOpcode() == BO_Comma) { // ,
2345  autoCreateBlock();
2346  appendStmt(Block, B);
2347  addStmt(B->getRHS());
2348  return addStmt(B->getLHS());
2349  }
2350 
2351  if (B->isAssignmentOp()) {
2352  if (asc.alwaysAdd(*this, B)) {
2353  autoCreateBlock();
2354  appendStmt(Block, B);
2355  }
2356  Visit(B->getLHS());
2357  return Visit(B->getRHS());
2358  }
2359 
2360  if (asc.alwaysAdd(*this, B)) {
2361  autoCreateBlock();
2362  appendStmt(Block, B);
2363  }
2364 
2365  CFGBlock *RBlock = Visit(B->getRHS());
2366  CFGBlock *LBlock = Visit(B->getLHS());
2367  // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr
2368  // containing a DoStmt, and the LHS doesn't create a new block, then we should
2369  // return RBlock. Otherwise we'll incorrectly return NULL.
2370  return (LBlock ? LBlock : RBlock);
2371 }
2372 
2373 CFGBlock *CFGBuilder::VisitNoRecurse(Expr *E, AddStmtChoice asc) {
2374  if (asc.alwaysAdd(*this, E)) {
2375  autoCreateBlock();
2376  appendStmt(Block, E);
2377  }
2378  return Block;
2379 }
2380 
2381 CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) {
2382  // "break" is a control-flow statement. Thus we stop processing the current
2383  // block.
2384  if (badCFG)
2385  return nullptr;
2386 
2387  // Now create a new block that ends with the break statement.
2388  Block = createBlock(false);
2389  Block->setTerminator(B);
2390 
2391  // If there is no target for the break, then we are looking at an incomplete
2392  // AST. This means that the CFG cannot be constructed.
2393  if (BreakJumpTarget.block) {
2394  addAutomaticObjHandling(ScopePos, BreakJumpTarget.scopePosition, B);
2395  addSuccessor(Block, BreakJumpTarget.block);
2396  } else
2397  badCFG = true;
2398 
2399  return Block;
2400 }
2401 
2402 static bool CanThrow(Expr *E, ASTContext &Ctx) {
2403  QualType Ty = E->getType();
2404  if (Ty->isFunctionPointerType())
2405  Ty = Ty->getAs<PointerType>()->getPointeeType();
2406  else if (Ty->isBlockPointerType())
2407  Ty = Ty->getAs<BlockPointerType>()->getPointeeType();
2408 
2409  const FunctionType *FT = Ty->getAs<FunctionType>();
2410  if (FT) {
2411  if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT))
2412  if (!isUnresolvedExceptionSpec(Proto->getExceptionSpecType()) &&
2413  Proto->isNothrow())
2414  return false;
2415  }
2416  return true;
2417 }
2418 
2419 CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) {
2420  // Compute the callee type.
2421  QualType calleeType = C->getCallee()->getType();
2422  if (calleeType == Context->BoundMemberTy) {
2423  QualType boundType = Expr::findBoundMemberType(C->getCallee());
2424 
2425  // We should only get a null bound type if processing a dependent
2426  // CFG. Recover by assuming nothing.
2427  if (!boundType.isNull()) calleeType = boundType;
2428  }
2429 
2430  // If this is a call to a no-return function, this stops the block here.
2431  bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn();
2432 
2433  bool AddEHEdge = false;
2434 
2435  // Languages without exceptions are assumed to not throw.
2436  if (Context->getLangOpts().Exceptions) {
2437  if (BuildOpts.AddEHEdges)
2438  AddEHEdge = true;
2439  }
2440 
2441  // If this is a call to a builtin function, it might not actually evaluate
2442  // its arguments. Don't add them to the CFG if this is the case.
2443  bool OmitArguments = false;
2444 
2445  if (FunctionDecl *FD = C->getDirectCallee()) {
2446  // TODO: Support construction contexts for variadic function arguments.
2447  // These are a bit problematic and not very useful because passing
2448  // C++ objects as C-style variadic arguments doesn't work in general
2449  // (see [expr.call]).
2450  if (!FD->isVariadic())
2451  findConstructionContextsForArguments(C);
2452 
2453  if (FD->isNoReturn() || C->isBuiltinAssumeFalse(*Context))
2454  NoReturn = true;
2455  if (FD->hasAttr<NoThrowAttr>())
2456  AddEHEdge = false;
2457  if (FD->getBuiltinID() == Builtin::BI__builtin_object_size)
2458  OmitArguments = true;
2459  }
2460 
2461  if (!CanThrow(C->getCallee(), *Context))
2462  AddEHEdge = false;
2463 
2464  if (OmitArguments) {
2465  assert(!NoReturn && "noreturn calls with unevaluated args not implemented");
2466  assert(!AddEHEdge && "EH calls with unevaluated args not implemented");
2467  autoCreateBlock();
2468  appendStmt(Block, C);
2469  return Visit(C->getCallee());
2470  }
2471 
2472  if (!NoReturn && !AddEHEdge) {
2473  autoCreateBlock();
2474  appendCall(Block, C);
2475 
2476  return VisitChildren(C);
2477  }
2478 
2479  if (Block) {
2480  Succ = Block;
2481  if (badCFG)
2482  return nullptr;
2483  }
2484 
2485  if (NoReturn)
2486  Block = createNoReturnBlock();
2487  else
2488  Block = createBlock();
2489 
2490  appendCall(Block, C);
2491 
2492  if (AddEHEdge) {
2493  // Add exceptional edges.
2494  if (TryTerminatedBlock)
2495  addSuccessor(Block, TryTerminatedBlock);
2496  else
2497  addSuccessor(Block, &cfg->getExit());
2498  }
2499 
2500  return VisitChildren(C);
2501 }
2502 
2503 CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C,
2504  AddStmtChoice asc) {
2505  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2506  appendStmt(ConfluenceBlock, C);
2507  if (badCFG)
2508  return nullptr;
2509 
2510  AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2511  Succ = ConfluenceBlock;
2512  Block = nullptr;
2513  CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd);
2514  if (badCFG)
2515  return nullptr;
2516 
2517  Succ = ConfluenceBlock;
2518  Block = nullptr;
2519  CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd);
2520  if (badCFG)
2521  return nullptr;
2522 
2523  Block = createBlock(false);
2524  // See if this is a known constant.
2525  const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2526  addSuccessor(Block, KnownVal.isFalse() ? nullptr : LHSBlock);
2527  addSuccessor(Block, KnownVal.isTrue() ? nullptr : RHSBlock);
2528  Block->setTerminator(C);
2529  return addStmt(C->getCond());
2530 }
2531 
2532 CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) {
2533  LocalScope::const_iterator scopeBeginPos = ScopePos;
2534  addLocalScopeForStmt(C);
2535 
2536  if (!C->body_empty() && !isa<ReturnStmt>(*C->body_rbegin())) {
2537  // If the body ends with a ReturnStmt, the dtors will be added in
2538  // VisitReturnStmt.
2539  addAutomaticObjHandling(ScopePos, scopeBeginPos, C);
2540  }
2541 
2542  CFGBlock *LastBlock = Block;
2543 
2545  I != E; ++I ) {
2546  // If we hit a segment of code just containing ';' (NullStmts), we can
2547  // get a null block back. In such cases, just use the LastBlock
2548  if (CFGBlock *newBlock = addStmt(*I))
2549  LastBlock = newBlock;
2550 
2551  if (badCFG)
2552  return nullptr;
2553  }
2554 
2555  return LastBlock;
2556 }
2557 
2558 CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C,
2559  AddStmtChoice asc) {
2560  const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C);
2561  const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : nullptr);
2562 
2563  // Create the confluence block that will "merge" the results of the ternary
2564  // expression.
2565  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2566  appendStmt(ConfluenceBlock, C);
2567  if (badCFG)
2568  return nullptr;
2569 
2570  AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2571 
2572  // Create a block for the LHS expression if there is an LHS expression. A
2573  // GCC extension allows LHS to be NULL, causing the condition to be the
2574  // value that is returned instead.
2575  // e.g: x ?: y is shorthand for: x ? x : y;
2576  Succ = ConfluenceBlock;
2577  Block = nullptr;
2578  CFGBlock *LHSBlock = nullptr;
2579  const Expr *trueExpr = C->getTrueExpr();
2580  if (trueExpr != opaqueValue) {
2581  LHSBlock = Visit(C->getTrueExpr(), alwaysAdd);
2582  if (badCFG)
2583  return nullptr;
2584  Block = nullptr;
2585  }
2586  else
2587  LHSBlock = ConfluenceBlock;
2588 
2589  // Create the block for the RHS expression.
2590  Succ = ConfluenceBlock;
2591  CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd);
2592  if (badCFG)
2593  return nullptr;
2594 
2595  // If the condition is a logical '&&' or '||', build a more accurate CFG.
2596  if (BinaryOperator *Cond =
2597  dyn_cast<BinaryOperator>(C->getCond()->IgnoreParens()))
2598  if (Cond->isLogicalOp())
2599  return VisitLogicalOperator(Cond, C, LHSBlock, RHSBlock).first;
2600 
2601  // Create the block that will contain the condition.
2602  Block = createBlock(false);
2603 
2604  // See if this is a known constant.
2605  const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2606  addSuccessor(Block, LHSBlock, !KnownVal.isFalse());
2607  addSuccessor(Block, RHSBlock, !KnownVal.isTrue());
2608  Block->setTerminator(C);
2609  Expr *condExpr = C->getCond();
2610 
2611  if (opaqueValue) {
2612  // Run the condition expression if it's not trivially expressed in
2613  // terms of the opaque value (or if there is no opaque value).
2614  if (condExpr != opaqueValue)
2615  addStmt(condExpr);
2616 
2617  // Before that, run the common subexpression if there was one.
2618  // At least one of this or the above will be run.
2619  return addStmt(BCO->getCommon());
2620  }
2621 
2622  return addStmt(condExpr);
2623 }
2624 
2625 CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) {
2626  // Check if the Decl is for an __label__. If so, elide it from the
2627  // CFG entirely.
2628  if (isa<LabelDecl>(*DS->decl_begin()))
2629  return Block;
2630 
2631  // This case also handles static_asserts.
2632  if (DS->isSingleDecl())
2633  return VisitDeclSubExpr(DS);
2634 
2635  CFGBlock *B = nullptr;
2636 
2637  // Build an individual DeclStmt for each decl.
2639  E = DS->decl_rend();
2640  I != E; ++I) {
2641 
2642  // Allocate the DeclStmt using the BumpPtrAllocator. It will get
2643  // automatically freed with the CFG.
2644  DeclGroupRef DG(*I);
2645  Decl *D = *I;
2646  DeclStmt *DSNew = new (Context) DeclStmt(DG, D->getLocation(), GetEndLoc(D));
2647  cfg->addSyntheticDeclStmt(DSNew, DS);
2648 
2649  // Append the fake DeclStmt to block.
2650  B = VisitDeclSubExpr(DSNew);
2651  }
2652 
2653  return B;
2654 }
2655 
2656 /// VisitDeclSubExpr - Utility method to add block-level expressions for
2657 /// DeclStmts and initializers in them.
2658 CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) {
2659  assert(DS->isSingleDecl() && "Can handle single declarations only.");
2660  VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl());
2661 
2662  if (!VD) {
2663  // Of everything that can be declared in a DeclStmt, only VarDecls impact
2664  // runtime semantics.
2665  return Block;
2666  }
2667 
2668  bool HasTemporaries = false;
2669 
2670  // Guard static initializers under a branch.
2671  CFGBlock *blockAfterStaticInit = nullptr;
2672 
2673  if (BuildOpts.AddStaticInitBranches && VD->isStaticLocal()) {
2674  // For static variables, we need to create a branch to track
2675  // whether or not they are initialized.
2676  if (Block) {
2677  Succ = Block;
2678  Block = nullptr;
2679  if (badCFG)
2680  return nullptr;
2681  }
2682  blockAfterStaticInit = Succ;
2683  }
2684 
2685  // Destructors of temporaries in initialization expression should be called
2686  // after initialization finishes.
2687  Expr *Init = VD->getInit();
2688  if (Init) {
2689  HasTemporaries = isa<ExprWithCleanups>(Init);
2690 
2691  if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
2692  // Generate destructors for temporaries in initialization expression.
2693  TempDtorContext Context;
2694  VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
2695  /*BindToTemporary=*/false, Context);
2696  }
2697  }
2698 
2699  autoCreateBlock();
2700  appendStmt(Block, DS);
2701 
2702  findConstructionContexts(
2703  ConstructionContextLayer::create(cfg->getBumpVectorContext(), DS),
2704  Init);
2705 
2706  // Keep track of the last non-null block, as 'Block' can be nulled out
2707  // if the initializer expression is something like a 'while' in a
2708  // statement-expression.
2709  CFGBlock *LastBlock = Block;
2710 
2711  if (Init) {
2712  if (HasTemporaries) {
2713  // For expression with temporaries go directly to subexpression to omit
2714  // generating destructors for the second time.
2715  ExprWithCleanups *EC = cast<ExprWithCleanups>(Init);
2716  if (CFGBlock *newBlock = Visit(EC->getSubExpr()))
2717  LastBlock = newBlock;
2718  }
2719  else {
2720  if (CFGBlock *newBlock = Visit(Init))
2721  LastBlock = newBlock;
2722  }
2723  }
2724 
2725  // If the type of VD is a VLA, then we must process its size expressions.
2726  for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr());
2727  VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr())) {
2728  if (CFGBlock *newBlock = addStmt(VA->getSizeExpr()))
2729  LastBlock = newBlock;
2730  }
2731 
2732  maybeAddScopeBeginForVarDecl(Block, VD, DS);
2733 
2734  // Remove variable from local scope.
2735  if (ScopePos && VD == *ScopePos)
2736  ++ScopePos;
2737 
2738  CFGBlock *B = LastBlock;
2739  if (blockAfterStaticInit) {
2740  Succ = B;
2741  Block = createBlock(false);
2742  Block->setTerminator(DS);
2743  addSuccessor(Block, blockAfterStaticInit);
2744  addSuccessor(Block, B);
2745  B = Block;
2746  }
2747 
2748  return B;
2749 }
2750 
2751 CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) {
2752  // We may see an if statement in the middle of a basic block, or it may be the
2753  // first statement we are processing. In either case, we create a new basic
2754  // block. First, we create the blocks for the then...else statements, and
2755  // then we create the block containing the if statement. If we were in the
2756  // middle of a block, we stop processing that block. That block is then the
2757  // implicit successor for the "then" and "else" clauses.
2758 
2759  // Save local scope position because in case of condition variable ScopePos
2760  // won't be restored when traversing AST.
2761  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2762 
2763  // Create local scope for C++17 if init-stmt if one exists.
2764  if (Stmt *Init = I->getInit())
2765  addLocalScopeForStmt(Init);
2766 
2767  // Create local scope for possible condition variable.
2768  // Store scope position. Add implicit destructor.
2769  if (VarDecl *VD = I->getConditionVariable())
2770  addLocalScopeForVarDecl(VD);
2771 
2772  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), I);
2773 
2774  // The block we were processing is now finished. Make it the successor
2775  // block.
2776  if (Block) {
2777  Succ = Block;
2778  if (badCFG)
2779  return nullptr;
2780  }
2781 
2782  // Process the false branch.
2783  CFGBlock *ElseBlock = Succ;
2784 
2785  if (Stmt *Else = I->getElse()) {
2786  SaveAndRestore<CFGBlock*> sv(Succ);
2787 
2788  // NULL out Block so that the recursive call to Visit will
2789  // create a new basic block.
2790  Block = nullptr;
2791 
2792  // If branch is not a compound statement create implicit scope
2793  // and add destructors.
2794  if (!isa<CompoundStmt>(Else))
2795  addLocalScopeAndDtors(Else);
2796 
2797  ElseBlock = addStmt(Else);
2798 
2799  if (!ElseBlock) // Can occur when the Else body has all NullStmts.
2800  ElseBlock = sv.get();
2801  else if (Block) {
2802  if (badCFG)
2803  return nullptr;
2804  }
2805  }
2806 
2807  // Process the true branch.
2808  CFGBlock *ThenBlock;
2809  {
2810  Stmt *Then = I->getThen();
2811  assert(Then);
2812  SaveAndRestore<CFGBlock*> sv(Succ);
2813  Block = nullptr;
2814 
2815  // If branch is not a compound statement create implicit scope
2816  // and add destructors.
2817  if (!isa<CompoundStmt>(Then))
2818  addLocalScopeAndDtors(Then);
2819 
2820  ThenBlock = addStmt(Then);
2821 
2822  if (!ThenBlock) {
2823  // We can reach here if the "then" body has all NullStmts.
2824  // Create an empty block so we can distinguish between true and false
2825  // branches in path-sensitive analyses.
2826  ThenBlock = createBlock(false);
2827  addSuccessor(ThenBlock, sv.get());
2828  } else if (Block) {
2829  if (badCFG)
2830  return nullptr;
2831  }
2832  }
2833 
2834  // Specially handle "if (expr1 || ...)" and "if (expr1 && ...)" by
2835  // having these handle the actual control-flow jump. Note that
2836  // if we introduce a condition variable, e.g. "if (int x = exp1 || exp2)"
2837  // we resort to the old control-flow behavior. This special handling
2838  // removes infeasible paths from the control-flow graph by having the
2839  // control-flow transfer of '&&' or '||' go directly into the then/else
2840  // blocks directly.
2841  BinaryOperator *Cond =
2843  ? nullptr
2844  : dyn_cast<BinaryOperator>(I->getCond()->IgnoreParens());
2845  CFGBlock *LastBlock;
2846  if (Cond && Cond->isLogicalOp())
2847  LastBlock = VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first;
2848  else {
2849  // Now create a new block containing the if statement.
2850  Block = createBlock(false);
2851 
2852  // Set the terminator of the new block to the If statement.
2853  Block->setTerminator(I);
2854 
2855  // See if this is a known constant.
2856  const TryResult &KnownVal = tryEvaluateBool(I->getCond());
2857 
2858  // Add the successors. If we know that specific branches are
2859  // unreachable, inform addSuccessor() of that knowledge.
2860  addSuccessor(Block, ThenBlock, /* isReachable = */ !KnownVal.isFalse());
2861  addSuccessor(Block, ElseBlock, /* isReachable = */ !KnownVal.isTrue());
2862 
2863  // Add the condition as the last statement in the new block. This may
2864  // create new blocks as the condition may contain control-flow. Any newly
2865  // created blocks will be pointed to be "Block".
2866  LastBlock = addStmt(I->getCond());
2867 
2868  // If the IfStmt contains a condition variable, add it and its
2869  // initializer to the CFG.
2870  if (const DeclStmt* DS = I->getConditionVariableDeclStmt()) {
2871  autoCreateBlock();
2872  LastBlock = addStmt(const_cast<DeclStmt *>(DS));
2873  }
2874  }
2875 
2876  // Finally, if the IfStmt contains a C++17 init-stmt, add it to the CFG.
2877  if (Stmt *Init = I->getInit()) {
2878  autoCreateBlock();
2879  LastBlock = addStmt(Init);
2880  }
2881 
2882  return LastBlock;
2883 }
2884 
2885 CFGBlock *CFGBuilder::VisitReturnStmt(Stmt *S) {
2886  // If we were in the middle of a block we stop processing that block.
2887  //
2888  // NOTE: If a "return" or "co_return" appears in the middle of a block, this
2889  // means that the code afterwards is DEAD (unreachable). We still keep
2890  // a basic block for that code; a simple "mark-and-sweep" from the entry
2891  // block will be able to report such dead blocks.
2892  assert(isa<ReturnStmt>(S) || isa<CoreturnStmt>(S));
2893 
2894  // Create the new block.
2895  Block = createBlock(false);
2896 
2897  addAutomaticObjHandling(ScopePos, LocalScope::const_iterator(), S);
2898 
2899  if (auto *R = dyn_cast<ReturnStmt>(S))
2900  findConstructionContexts(
2901  ConstructionContextLayer::create(cfg->getBumpVectorContext(), R),
2902  R->getRetValue());
2903 
2904  // If the one of the destructors does not return, we already have the Exit
2905  // block as a successor.
2906  if (!Block->hasNoReturnElement())
2907  addSuccessor(Block, &cfg->getExit());
2908 
2909  // Add the return statement to the block. This may create new blocks if R
2910  // contains control-flow (short-circuit operations).
2911  return VisitStmt(S, AddStmtChoice::AlwaysAdd);
2912 }
2913 
2914 CFGBlock *CFGBuilder::VisitSEHExceptStmt(SEHExceptStmt *ES) {
2915  // SEHExceptStmt are treated like labels, so they are the first statement in a
2916  // block.
2917 
2918  // Save local scope position because in case of exception variable ScopePos
2919  // won't be restored when traversing AST.
2920  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2921 
2922  addStmt(ES->getBlock());
2923  CFGBlock *SEHExceptBlock = Block;
2924  if (!SEHExceptBlock)
2925  SEHExceptBlock = createBlock();
2926 
2927  appendStmt(SEHExceptBlock, ES);
2928 
2929  // Also add the SEHExceptBlock as a label, like with regular labels.
2930  SEHExceptBlock->setLabel(ES);
2931 
2932  // Bail out if the CFG is bad.
2933  if (badCFG)
2934  return nullptr;
2935 
2936  // We set Block to NULL to allow lazy creation of a new block (if necessary).
2937  Block = nullptr;
2938 
2939  return SEHExceptBlock;
2940 }
2941 
2942 CFGBlock *CFGBuilder::VisitSEHFinallyStmt(SEHFinallyStmt *FS) {
2943  return VisitCompoundStmt(FS->getBlock());
2944 }
2945 
2946 CFGBlock *CFGBuilder::VisitSEHLeaveStmt(SEHLeaveStmt *LS) {
2947  // "__leave" is a control-flow statement. Thus we stop processing the current
2948  // block.
2949  if (badCFG)
2950  return nullptr;
2951 
2952  // Now create a new block that ends with the __leave statement.
2953  Block = createBlock(false);
2954  Block->setTerminator(LS);
2955 
2956  // If there is no target for the __leave, then we are looking at an incomplete
2957  // AST. This means that the CFG cannot be constructed.
2958  if (SEHLeaveJumpTarget.block) {
2959  addAutomaticObjHandling(ScopePos, SEHLeaveJumpTarget.scopePosition, LS);
2960  addSuccessor(Block, SEHLeaveJumpTarget.block);
2961  } else
2962  badCFG = true;
2963 
2964  return Block;
2965 }
2966 
2967 CFGBlock *CFGBuilder::VisitSEHTryStmt(SEHTryStmt *Terminator) {
2968  // "__try"/"__except"/"__finally" is a control-flow statement. Thus we stop
2969  // processing the current block.
2970  CFGBlock *SEHTrySuccessor = nullptr;
2971 
2972  if (Block) {
2973  if (badCFG)
2974  return nullptr;
2975  SEHTrySuccessor = Block;
2976  } else SEHTrySuccessor = Succ;
2977 
2978  // FIXME: Implement __finally support.
2979  if (Terminator->getFinallyHandler())
2980  return NYS();
2981 
2982  CFGBlock *PrevSEHTryTerminatedBlock = TryTerminatedBlock;
2983 
2984  // Create a new block that will contain the __try statement.
2985  CFGBlock *NewTryTerminatedBlock = createBlock(false);
2986 
2987  // Add the terminator in the __try block.
2988  NewTryTerminatedBlock->setTerminator(Terminator);
2989 
2990  if (SEHExceptStmt *Except = Terminator->getExceptHandler()) {
2991  // The code after the try is the implicit successor if there's an __except.
2992  Succ = SEHTrySuccessor;
2993  Block = nullptr;
2994  CFGBlock *ExceptBlock = VisitSEHExceptStmt(Except);
2995  if (!ExceptBlock)
2996  return nullptr;
2997  // Add this block to the list of successors for the block with the try
2998  // statement.
2999  addSuccessor(NewTryTerminatedBlock, ExceptBlock);
3000  }
3001  if (PrevSEHTryTerminatedBlock)
3002  addSuccessor(NewTryTerminatedBlock, PrevSEHTryTerminatedBlock);
3003  else
3004  addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
3005 
3006  // The code after the try is the implicit successor.
3007  Succ = SEHTrySuccessor;
3008 
3009  // Save the current "__try" context.
3010  SaveAndRestore<CFGBlock *> save_try(TryTerminatedBlock,
3011  NewTryTerminatedBlock);
3012  cfg->addTryDispatchBlock(TryTerminatedBlock);
3013 
3014  // Save the current value for the __leave target.
3015  // All __leaves should go to the code following the __try
3016  // (FIXME: or if the __try has a __finally, to the __finally.)
3017  SaveAndRestore<JumpTarget> save_break(SEHLeaveJumpTarget);
3018  SEHLeaveJumpTarget = JumpTarget(SEHTrySuccessor, ScopePos);
3019 
3020  assert(Terminator->getTryBlock() && "__try must contain a non-NULL body");
3021  Block = nullptr;
3022  return addStmt(Terminator->getTryBlock());
3023 }
3024 
3025 CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) {
3026  // Get the block of the labeled statement. Add it to our map.
3027  addStmt(L->getSubStmt());
3028  CFGBlock *LabelBlock = Block;
3029 
3030  if (!LabelBlock) // This can happen when the body is empty, i.e.
3031  LabelBlock = createBlock(); // scopes that only contains NullStmts.
3032 
3033  assert(LabelMap.find(L->getDecl()) == LabelMap.end() &&
3034  "label already in map");
3035  LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos);
3036 
3037  // Labels partition blocks, so this is the end of the basic block we were
3038  // processing (L is the block's label). Because this is label (and we have
3039  // already processed the substatement) there is no extra control-flow to worry
3040  // about.
3041  LabelBlock->setLabel(L);
3042  if (badCFG)
3043  return nullptr;
3044 
3045  // We set Block to NULL to allow lazy creation of a new block (if necessary);
3046  Block = nullptr;
3047 
3048  // This block is now the implicit successor of other blocks.
3049  Succ = LabelBlock;
3050 
3051  return LabelBlock;
3052 }
3053 
3054 CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) {
3055  CFGBlock *LastBlock = VisitNoRecurse(E, asc);
3056  for (const BlockDecl::Capture &CI : E->getBlockDecl()->captures()) {
3057  if (Expr *CopyExpr = CI.getCopyExpr()) {
3058  CFGBlock *Tmp = Visit(CopyExpr);
3059  if (Tmp)
3060  LastBlock = Tmp;
3061  }
3062  }
3063  return LastBlock;
3064 }
3065 
3066 CFGBlock *CFGBuilder::VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc) {
3067  CFGBlock *LastBlock = VisitNoRecurse(E, asc);
3069  et = E->capture_init_end(); it != et; ++it) {
3070  if (Expr *Init = *it) {
3071  CFGBlock *Tmp = Visit(Init);
3072  if (Tmp)
3073  LastBlock = Tmp;
3074  }
3075  }
3076  return LastBlock;
3077 }
3078 
3079 CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) {
3080  // Goto is a control-flow statement. Thus we stop processing the current
3081  // block and create a new one.
3082 
3083  Block = createBlock(false);
3084  Block->setTerminator(G);
3085 
3086  // If we already know the mapping to the label block add the successor now.
3087  LabelMapTy::iterator I = LabelMap.find(G->getLabel());
3088 
3089  if (I == LabelMap.end())
3090  // We will need to backpatch this block later.
3091  BackpatchBlocks.push_back(JumpSource(Block, ScopePos));
3092  else {
3093  JumpTarget JT = I->second;
3094  addAutomaticObjHandling(ScopePos, JT.scopePosition, G);
3095  addSuccessor(Block, JT.block);
3096  }
3097 
3098  return Block;
3099 }
3100 
3101 CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) {
3102  CFGBlock *LoopSuccessor = nullptr;
3103 
3104  // Save local scope position because in case of condition variable ScopePos
3105  // won't be restored when traversing AST.
3106  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3107 
3108  // Create local scope for init statement and possible condition variable.
3109  // Add destructor for init statement and condition variable.
3110  // Store scope position for continue statement.
3111  if (Stmt *Init = F->getInit())
3112  addLocalScopeForStmt(Init);
3113  LocalScope::const_iterator LoopBeginScopePos = ScopePos;
3114 
3115  if (VarDecl *VD = F->getConditionVariable())
3116  addLocalScopeForVarDecl(VD);
3117  LocalScope::const_iterator ContinueScopePos = ScopePos;
3118 
3119  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), F);
3120 
3121  addLoopExit(F);
3122 
3123  // "for" is a control-flow statement. Thus we stop processing the current
3124  // block.
3125  if (Block) {
3126  if (badCFG)
3127  return nullptr;
3128  LoopSuccessor = Block;
3129  } else
3130  LoopSuccessor = Succ;
3131 
3132  // Save the current value for the break targets.
3133  // All breaks should go to the code following the loop.
3134  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3135  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3136 
3137  CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
3138 
3139  // Now create the loop body.
3140  {
3141  assert(F->getBody());
3142 
3143  // Save the current values for Block, Succ, continue and break targets.
3144  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3145  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
3146 
3147  // Create an empty block to represent the transition block for looping back
3148  // to the head of the loop. If we have increment code, it will
3149  // go in this block as well.
3150  Block = Succ = TransitionBlock = createBlock(false);
3151  TransitionBlock->setLoopTarget(F);
3152 
3153  if (Stmt *I = F->getInc()) {
3154  // Generate increment code in its own basic block. This is the target of
3155  // continue statements.
3156  Succ = addStmt(I);
3157  }
3158 
3159  // Finish up the increment (or empty) block if it hasn't been already.
3160  if (Block) {
3161  assert(Block == Succ);
3162  if (badCFG)
3163  return nullptr;
3164  Block = nullptr;
3165  }
3166 
3167  // The starting block for the loop increment is the block that should
3168  // represent the 'loop target' for looping back to the start of the loop.
3169  ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
3170  ContinueJumpTarget.block->setLoopTarget(F);
3171 
3172  // Loop body should end with destructor of Condition variable (if any).
3173  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, F);
3174 
3175  // If body is not a compound statement create implicit scope
3176  // and add destructors.
3177  if (!isa<CompoundStmt>(F->getBody()))
3178  addLocalScopeAndDtors(F->getBody());
3179 
3180  // Now populate the body block, and in the process create new blocks as we
3181  // walk the body of the loop.
3182  BodyBlock = addStmt(F->getBody());
3183 
3184  if (!BodyBlock) {
3185  // In the case of "for (...;...;...);" we can have a null BodyBlock.
3186  // Use the continue jump target as the proxy for the body.
3187  BodyBlock = ContinueJumpTarget.block;
3188  }
3189  else if (badCFG)
3190  return nullptr;
3191  }
3192 
3193  // Because of short-circuit evaluation, the condition of the loop can span
3194  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3195  // evaluate the condition.
3196  CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
3197 
3198  do {
3199  Expr *C = F->getCond();
3200  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3201 
3202  // Specially handle logical operators, which have a slightly
3203  // more optimal CFG representation.
3204  if (BinaryOperator *Cond =
3205  dyn_cast_or_null<BinaryOperator>(C ? C->IgnoreParens() : nullptr))
3206  if (Cond->isLogicalOp()) {
3207  std::tie(EntryConditionBlock, ExitConditionBlock) =
3208  VisitLogicalOperator(Cond, F, BodyBlock, LoopSuccessor);
3209  break;
3210  }
3211 
3212  // The default case when not handling logical operators.
3213  EntryConditionBlock = ExitConditionBlock = createBlock(false);
3214  ExitConditionBlock->setTerminator(F);
3215 
3216  // See if this is a known constant.
3217  TryResult KnownVal(true);
3218 
3219  if (C) {
3220  // Now add the actual condition to the condition block.
3221  // Because the condition itself may contain control-flow, new blocks may
3222  // be created. Thus we update "Succ" after adding the condition.
3223  Block = ExitConditionBlock;
3224  EntryConditionBlock = addStmt(C);
3225 
3226  // If this block contains a condition variable, add both the condition
3227  // variable and initializer to the CFG.
3228  if (VarDecl *VD = F->getConditionVariable()) {
3229  if (Expr *Init = VD->getInit()) {
3230  autoCreateBlock();
3231  const DeclStmt *DS = F->getConditionVariableDeclStmt();
3232  assert(DS->isSingleDecl());
3233  findConstructionContexts(
3234  ConstructionContextLayer::create(cfg->getBumpVectorContext(), DS),
3235  Init);
3236  appendStmt(Block, DS);
3237  EntryConditionBlock = addStmt(Init);
3238  assert(Block == EntryConditionBlock);
3239  maybeAddScopeBeginForVarDecl(EntryConditionBlock, VD, C);
3240  }
3241  }
3242 
3243  if (Block && badCFG)
3244  return nullptr;
3245 
3246  KnownVal = tryEvaluateBool(C);
3247  }
3248 
3249  // Add the loop body entry as a successor to the condition.
3250  addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
3251  // Link up the condition block with the code that follows the loop. (the
3252  // false branch).
3253  addSuccessor(ExitConditionBlock,
3254  KnownVal.isTrue() ? nullptr : LoopSuccessor);
3255  } while (false);
3256 
3257  // Link up the loop-back block to the entry condition block.
3258  addSuccessor(TransitionBlock, EntryConditionBlock);
3259 
3260  // The condition block is the implicit successor for any code above the loop.
3261  Succ = EntryConditionBlock;
3262 
3263  // If the loop contains initialization, create a new block for those
3264  // statements. This block can also contain statements that precede the loop.
3265  if (Stmt *I = F->getInit()) {
3266  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3267  ScopePos = LoopBeginScopePos;
3268  Block = createBlock();
3269  return addStmt(I);
3270  }
3271 
3272  // There is no loop initialization. We are thus basically a while loop.
3273  // NULL out Block to force lazy block construction.
3274  Block = nullptr;
3275  Succ = EntryConditionBlock;
3276  return EntryConditionBlock;
3277 }
3278 
3279 CFGBlock *
3280 CFGBuilder::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *MTE,
3281  AddStmtChoice asc) {
3282  findConstructionContexts(
3283  ConstructionContextLayer::create(cfg->getBumpVectorContext(), MTE),
3284  MTE->getTemporary());
3285 
3286  return VisitStmt(MTE, asc);
3287 }
3288 
3289 CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) {
3290  if (asc.alwaysAdd(*this, M)) {
3291  autoCreateBlock();
3292  appendStmt(Block, M);
3293  }
3294  return Visit(M->getBase());
3295 }
3296 
3297 CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) {
3298  // Objective-C fast enumeration 'for' statements:
3299  // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC
3300  //
3301  // for ( Type newVariable in collection_expression ) { statements }
3302  //
3303  // becomes:
3304  //
3305  // prologue:
3306  // 1. collection_expression
3307  // T. jump to loop_entry
3308  // loop_entry:
3309  // 1. side-effects of element expression
3310  // 1. ObjCForCollectionStmt [performs binding to newVariable]
3311  // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil]
3312  // TB:
3313  // statements
3314  // T. jump to loop_entry
3315  // FB:
3316  // what comes after
3317  //
3318  // and
3319  //
3320  // Type existingItem;
3321  // for ( existingItem in expression ) { statements }
3322  //
3323  // becomes:
3324  //
3325  // the same with newVariable replaced with existingItem; the binding works
3326  // the same except that for one ObjCForCollectionStmt::getElement() returns
3327  // a DeclStmt and the other returns a DeclRefExpr.
3328 
3329  CFGBlock *LoopSuccessor = nullptr;
3330 
3331  if (Block) {
3332  if (badCFG)
3333  return nullptr;
3334  LoopSuccessor = Block;
3335  Block = nullptr;
3336  } else
3337  LoopSuccessor = Succ;
3338 
3339  // Build the condition blocks.
3340  CFGBlock *ExitConditionBlock = createBlock(false);
3341 
3342  // Set the terminator for the "exit" condition block.
3343  ExitConditionBlock->setTerminator(S);
3344 
3345  // The last statement in the block should be the ObjCForCollectionStmt, which
3346  // performs the actual binding to 'element' and determines if there are any
3347  // more items in the collection.
3348  appendStmt(ExitConditionBlock, S);
3349  Block = ExitConditionBlock;
3350 
3351  // Walk the 'element' expression to see if there are any side-effects. We
3352  // generate new blocks as necessary. We DON'T add the statement by default to
3353  // the CFG unless it contains control-flow.
3354  CFGBlock *EntryConditionBlock = Visit(S->getElement(),
3355  AddStmtChoice::NotAlwaysAdd);
3356  if (Block) {
3357  if (badCFG)
3358  return nullptr;
3359  Block = nullptr;
3360  }
3361 
3362  // The condition block is the implicit successor for the loop body as well as
3363  // any code above the loop.
3364  Succ = EntryConditionBlock;
3365 
3366  // Now create the true branch.
3367  {
3368  // Save the current values for Succ, continue and break targets.
3369  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3370  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3371  save_break(BreakJumpTarget);
3372 
3373  // Add an intermediate block between the BodyBlock and the
3374  // EntryConditionBlock to represent the "loop back" transition, for looping
3375  // back to the head of the loop.
3376  CFGBlock *LoopBackBlock = nullptr;
3377  Succ = LoopBackBlock = createBlock();
3378  LoopBackBlock->setLoopTarget(S);
3379 
3380  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3381  ContinueJumpTarget = JumpTarget(Succ, ScopePos);
3382 
3383  CFGBlock *BodyBlock = addStmt(S->getBody());
3384 
3385  if (!BodyBlock)
3386  BodyBlock = ContinueJumpTarget.block; // can happen for "for (X in Y) ;"
3387  else if (Block) {
3388  if (badCFG)
3389  return nullptr;
3390  }
3391 
3392  // This new body block is a successor to our "exit" condition block.
3393  addSuccessor(ExitConditionBlock, BodyBlock);
3394  }
3395 
3396  // Link up the condition block with the code that follows the loop.
3397  // (the false branch).
3398  addSuccessor(ExitConditionBlock, LoopSuccessor);
3399 
3400  // Now create a prologue block to contain the collection expression.
3401  Block = createBlock();
3402  return addStmt(S->getCollection());
3403 }
3404 
3405 CFGBlock *CFGBuilder::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) {
3406  // Inline the body.
3407  return addStmt(S->getSubStmt());
3408  // TODO: consider adding cleanups for the end of @autoreleasepool scope.
3409 }
3410 
3411 CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) {
3412  // FIXME: Add locking 'primitives' to CFG for @synchronized.
3413 
3414  // Inline the body.
3415  CFGBlock *SyncBlock = addStmt(S->getSynchBody());
3416 
3417  // The sync body starts its own basic block. This makes it a little easier
3418  // for diagnostic clients.
3419  if (SyncBlock) {
3420  if (badCFG)
3421  return nullptr;
3422 
3423  Block = nullptr;
3424  Succ = SyncBlock;
3425  }
3426 
3427  // Add the @synchronized to the CFG.
3428  autoCreateBlock();
3429  appendStmt(Block, S);
3430 
3431  // Inline the sync expression.
3432  return addStmt(S->getSynchExpr());
3433 }
3434 
3435 CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) {
3436  // FIXME
3437  return NYS();
3438 }
3439 
3440 CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) {
3441  autoCreateBlock();
3442 
3443  // Add the PseudoObject as the last thing.
3444  appendStmt(Block, E);
3445 
3446  CFGBlock *lastBlock = Block;
3447 
3448  // Before that, evaluate all of the semantics in order. In
3449  // CFG-land, that means appending them in reverse order.
3450  for (unsigned i = E->getNumSemanticExprs(); i != 0; ) {
3451  Expr *Semantic = E->getSemanticExpr(--i);
3452 
3453  // If the semantic is an opaque value, we're being asked to bind
3454  // it to its source expression.
3455  if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
3456  Semantic = OVE->getSourceExpr();
3457 
3458  if (CFGBlock *B = Visit(Semantic))
3459  lastBlock = B;
3460  }
3461 
3462  return lastBlock;
3463 }
3464 
3465 CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) {
3466  CFGBlock *LoopSuccessor = nullptr;
3467 
3468  // Save local scope position because in case of condition variable ScopePos
3469  // won't be restored when traversing AST.
3470  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3471 
3472  // Create local scope for possible condition variable.
3473  // Store scope position for continue statement.
3474  LocalScope::const_iterator LoopBeginScopePos = ScopePos;
3475  if (VarDecl *VD = W->getConditionVariable()) {
3476  addLocalScopeForVarDecl(VD);
3477  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3478  }
3479  addLoopExit(W);
3480 
3481  // "while" is a control-flow statement. Thus we stop processing the current
3482  // block.
3483  if (Block) {
3484  if (badCFG)
3485  return nullptr;
3486  LoopSuccessor = Block;
3487  Block = nullptr;
3488  } else {
3489  LoopSuccessor = Succ;
3490  }
3491 
3492  CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
3493 
3494  // Process the loop body.
3495  {
3496  assert(W->getBody());
3497 
3498  // Save the current values for Block, Succ, continue and break targets.
3499  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3500  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3501  save_break(BreakJumpTarget);
3502 
3503  // Create an empty block to represent the transition block for looping back
3504  // to the head of the loop.
3505  Succ = TransitionBlock = createBlock(false);
3506  TransitionBlock->setLoopTarget(W);
3507  ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos);
3508 
3509  // All breaks should go to the code following the loop.
3510  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3511 
3512  // Loop body should end with destructor of Condition variable (if any).
3513  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3514 
3515  // If body is not a compound statement create implicit scope
3516  // and add destructors.
3517  if (!isa<CompoundStmt>(W->getBody()))
3518  addLocalScopeAndDtors(W->getBody());
3519 
3520  // Create the body. The returned block is the entry to the loop body.
3521  BodyBlock = addStmt(W->getBody());
3522 
3523  if (!BodyBlock)
3524  BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;"
3525  else if (Block && badCFG)
3526  return nullptr;
3527  }
3528 
3529  // Because of short-circuit evaluation, the condition of the loop can span
3530  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3531  // evaluate the condition.
3532  CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
3533 
3534  do {
3535  Expr *C = W->getCond();
3536 
3537  // Specially handle logical operators, which have a slightly
3538  // more optimal CFG representation.
3539  if (BinaryOperator *Cond = dyn_cast<BinaryOperator>(C->IgnoreParens()))
3540  if (Cond->isLogicalOp()) {
3541  std::tie(EntryConditionBlock, ExitConditionBlock) =
3542  VisitLogicalOperator(Cond, W, BodyBlock, LoopSuccessor);
3543  break;
3544  }
3545 
3546  // The default case when not handling logical operators.
3547  ExitConditionBlock = createBlock(false);
3548  ExitConditionBlock->setTerminator(W);
3549 
3550  // Now add the actual condition to the condition block.
3551  // Because the condition itself may contain control-flow, new blocks may
3552  // be created. Thus we update "Succ" after adding the condition.
3553  Block = ExitConditionBlock;
3554  Block = EntryConditionBlock = addStmt(C);
3555 
3556  // If this block contains a condition variable, add both the condition
3557  // variable and initializer to the CFG.
3558  if (VarDecl *VD = W->getConditionVariable()) {
3559  if (Expr *Init = VD->getInit()) {
3560  autoCreateBlock();
3561  const DeclStmt *DS = W->getConditionVariableDeclStmt();
3562  assert(DS->isSingleDecl());
3563  findConstructionContexts(
3564  ConstructionContextLayer::create(cfg->getBumpVectorContext(),
3565  const_cast<DeclStmt *>(DS)),
3566  Init);
3567  appendStmt(Block, DS);
3568  EntryConditionBlock = addStmt(Init);
3569  assert(Block == EntryConditionBlock);
3570  maybeAddScopeBeginForVarDecl(EntryConditionBlock, VD, C);
3571  }
3572  }
3573 
3574  if (Block && badCFG)
3575  return nullptr;
3576 
3577  // See if this is a known constant.
3578  const TryResult& KnownVal = tryEvaluateBool(C);
3579 
3580  // Add the loop body entry as a successor to the condition.
3581  addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
3582  // Link up the condition block with the code that follows the loop. (the
3583  // false branch).
3584  addSuccessor(ExitConditionBlock,
3585  KnownVal.isTrue() ? nullptr : LoopSuccessor);
3586  } while(false);
3587 
3588  // Link up the loop-back block to the entry condition block.
3589  addSuccessor(TransitionBlock, EntryConditionBlock);
3590 
3591  // There can be no more statements in the condition block since we loop back
3592  // to this block. NULL out Block to force lazy creation of another block.
3593  Block = nullptr;
3594 
3595  // Return the condition block, which is the dominating block for the loop.
3596  Succ = EntryConditionBlock;
3597  return EntryConditionBlock;
3598 }
3599 
3600 CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) {
3601  // FIXME: For now we pretend that @catch and the code it contains does not
3602  // exit.
3603  return Block;
3604 }
3605 
3606 CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) {
3607  // FIXME: This isn't complete. We basically treat @throw like a return
3608  // statement.
3609 
3610  // If we were in the middle of a block we stop processing that block.
3611  if (badCFG)
3612  return nullptr;
3613 
3614  // Create the new block.
3615  Block = createBlock(false);
3616 
3617  // The Exit block is the only successor.
3618  addSuccessor(Block, &cfg->getExit());
3619 
3620  // Add the statement to the block. This may create new blocks if S contains
3621  // control-flow (short-circuit operations).
3622  return VisitStmt(S, AddStmtChoice::AlwaysAdd);
3623 }
3624 
3625 CFGBlock *CFGBuilder::VisitObjCMessageExpr(ObjCMessageExpr *ME,
3626  AddStmtChoice asc) {
3627  findConstructionContextsForArguments(ME);
3628 
3629  autoCreateBlock();
3630  appendObjCMessage(Block, ME);
3631 
3632  return VisitChildren(ME);
3633 }
3634 
3635 CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) {
3636  // If we were in the middle of a block we stop processing that block.
3637  if (badCFG)
3638  return nullptr;
3639 
3640  // Create the new block.
3641  Block = createBlock(false);
3642 
3643  if (TryTerminatedBlock)
3644  // The current try statement is the only successor.
3645  addSuccessor(Block, TryTerminatedBlock);
3646  else
3647  // otherwise the Exit block is the only successor.
3648  addSuccessor(Block, &cfg->getExit());
3649 
3650  // Add the statement to the block. This may create new blocks if S contains
3651  // control-flow (short-circuit operations).
3652  return VisitStmt(T, AddStmtChoice::AlwaysAdd);
3653 }
3654 
3655 CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) {
3656  CFGBlock *LoopSuccessor = nullptr;
3657 
3658  addLoopExit(D);
3659 
3660  // "do...while" is a control-flow statement. Thus we stop processing the
3661  // current block.
3662  if (Block) {
3663  if (badCFG)
3664  return nullptr;
3665  LoopSuccessor = Block;
3666  } else
3667  LoopSuccessor = Succ;
3668 
3669  // Because of short-circuit evaluation, the condition of the loop can span
3670  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3671  // evaluate the condition.
3672  CFGBlock *ExitConditionBlock = createBlock(false);
3673  CFGBlock *EntryConditionBlock = ExitConditionBlock;
3674 
3675  // Set the terminator for the "exit" condition block.
3676  ExitConditionBlock->setTerminator(D);
3677 
3678  // Now add the actual condition to the condition block. Because the condition
3679  // itself may contain control-flow, new blocks may be created.
3680  if (Stmt *C = D->getCond()) {
3681  Block = ExitConditionBlock;
3682  EntryConditionBlock = addStmt(C);
3683  if (Block) {
3684  if (badCFG)
3685  return nullptr;
3686  }
3687  }
3688 
3689  // The condition block is the implicit successor for the loop body.
3690  Succ = EntryConditionBlock;
3691 
3692  // See if this is a known constant.
3693  const TryResult &KnownVal = tryEvaluateBool(D->getCond());
3694 
3695  // Process the loop body.
3696  CFGBlock *BodyBlock = nullptr;
3697  {
3698  assert(D->getBody());
3699 
3700  // Save the current values for Block, Succ, and continue and break targets
3701  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3702  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3703  save_break(BreakJumpTarget);
3704 
3705  // All continues within this loop should go to the condition block
3706  ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos);
3707 
3708  // All breaks should go to the code following the loop.
3709  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3710 
3711  // NULL out Block to force lazy instantiation of blocks for the body.
3712  Block = nullptr;
3713 
3714  // If body is not a compound statement create implicit scope
3715  // and add destructors.
3716  if (!isa<CompoundStmt>(D->getBody()))
3717  addLocalScopeAndDtors(D->getBody());
3718 
3719  // Create the body. The returned block is the entry to the loop body.
3720  BodyBlock = addStmt(D->getBody());
3721 
3722  if (!BodyBlock)
3723  BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)"
3724  else if (Block) {
3725  if (badCFG)
3726  return nullptr;
3727  }
3728 
3729  // Add an intermediate block between the BodyBlock and the
3730  // ExitConditionBlock to represent the "loop back" transition. Create an
3731  // empty block to represent the transition block for looping back to the
3732  // head of the loop.
3733  // FIXME: Can we do this more efficiently without adding another block?
3734  Block = nullptr;
3735  Succ = BodyBlock;
3736  CFGBlock *LoopBackBlock = createBlock();
3737  LoopBackBlock->setLoopTarget(D);
3738 
3739  if (!KnownVal.isFalse())
3740  // Add the loop body entry as a successor to the condition.
3741  addSuccessor(ExitConditionBlock, LoopBackBlock);
3742  else
3743  addSuccessor(ExitConditionBlock, nullptr);
3744  }
3745 
3746  // Link up the condition block with the code that follows the loop.
3747  // (the false branch).
3748  addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
3749 
3750  // There can be no more statements in the body block(s) since we loop back to
3751  // the body. NULL out Block to force lazy creation of another block.
3752  Block = nullptr;
3753 
3754  // Return the loop body, which is the dominating block for the loop.
3755  Succ = BodyBlock;
3756  return BodyBlock;
3757 }
3758 
3759 CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) {
3760  // "continue" is a control-flow statement. Thus we stop processing the
3761  // current block.
3762  if (badCFG)
3763  return nullptr;
3764 
3765  // Now create a new block that ends with the continue statement.
3766  Block = createBlock(false);
3767  Block->setTerminator(C);
3768 
3769  // If there is no target for the continue, then we are looking at an
3770  // incomplete AST. This means the CFG cannot be constructed.
3771  if (ContinueJumpTarget.block) {
3772  addAutomaticObjHandling(ScopePos, ContinueJumpTarget.scopePosition, C);
3773  addSuccessor(Block, ContinueJumpTarget.block);
3774  } else
3775  badCFG = true;
3776 
3777  return Block;
3778 }
3779 
3780 CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
3781  AddStmtChoice asc) {
3782  if (asc.alwaysAdd(*this, E)) {
3783  autoCreateBlock();
3784  appendStmt(Block, E);
3785  }
3786 
3787  // VLA types have expressions that must be evaluated.
3788  CFGBlock *lastBlock = Block;
3789 
3790  if (E->isArgumentType()) {
3791  for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr());
3792  VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr()))
3793  lastBlock = addStmt(VA->getSizeExpr());
3794  }
3795  return lastBlock;
3796 }
3797 
3798 /// VisitStmtExpr - Utility method to handle (nested) statement
3799 /// expressions (a GCC extension).
3800 CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) {
3801  if (asc.alwaysAdd(*this, SE)) {
3802  autoCreateBlock();
3803  appendStmt(Block, SE);
3804  }
3805  return VisitCompoundStmt(SE->getSubStmt());
3806 }
3807 
3808 CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) {
3809  // "switch" is a control-flow statement. Thus we stop processing the current
3810  // block.
3811  CFGBlock *SwitchSuccessor = nullptr;
3812 
3813  // Save local scope position because in case of condition variable ScopePos
3814  // won't be restored when traversing AST.
3815  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3816 
3817  // Create local scope for C++17 switch init-stmt if one exists.
3818  if (Stmt *Init = Terminator->getInit())
3819  addLocalScopeForStmt(Init);
3820 
3821  // Create local scope for possible condition variable.
3822  // Store scope position. Add implicit destructor.
3823  if (VarDecl *VD = Terminator->getConditionVariable())
3824  addLocalScopeForVarDecl(VD);
3825 
3826  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), Terminator);
3827 
3828  if (Block) {
3829  if (badCFG)
3830  return nullptr;
3831  SwitchSuccessor = Block;
3832  } else SwitchSuccessor = Succ;
3833 
3834  // Save the current "switch" context.
3835  SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock),
3836  save_default(DefaultCaseBlock);
3837  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3838 
3839  // Set the "default" case to be the block after the switch statement. If the
3840  // switch statement contains a "default:", this value will be overwritten with
3841  // the block for that code.
3842  DefaultCaseBlock = SwitchSuccessor;
3843 
3844  // Create a new block that will contain the switch statement.
3845  SwitchTerminatedBlock = createBlock(false);
3846 
3847  // Now process the switch body. The code after the switch is the implicit
3848  // successor.
3849  Succ = SwitchSuccessor;
3850  BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos);
3851 
3852  // When visiting the body, the case statements should automatically get linked
3853  // up to the switch. We also don't keep a pointer to the body, since all
3854  // control-flow from the switch goes to case/default statements.
3855  assert(Terminator->getBody() && "switch must contain a non-NULL body");
3856  Block = nullptr;
3857 
3858  // For pruning unreachable case statements, save the current state
3859  // for tracking the condition value.
3860  SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered,
3861  false);
3862 
3863  // Determine if the switch condition can be explicitly evaluated.
3864  assert(Terminator->getCond() && "switch condition must be non-NULL");
3865  Expr::EvalResult result;
3866  bool b = tryEvaluate(Terminator->getCond(), result);
3867  SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond,
3868  b ? &result : nullptr);
3869 
3870  // If body is not a compound statement create implicit scope
3871  // and add destructors.
3872  if (!isa<CompoundStmt>(Terminator->getBody()))
3873  addLocalScopeAndDtors(Terminator->getBody());
3874 
3875  addStmt(Terminator->getBody());
3876  if (Block) {
3877  if (badCFG)
3878  return nullptr;
3879  }
3880 
3881  // If we have no "default:" case, the default transition is to the code
3882  // following the switch body. Moreover, take into account if all the
3883  // cases of a switch are covered (e.g., switching on an enum value).
3884  //
3885  // Note: We add a successor to a switch that is considered covered yet has no
3886  // case statements if the enumeration has no enumerators.
3887  bool SwitchAlwaysHasSuccessor = false;
3888  SwitchAlwaysHasSuccessor |= switchExclusivelyCovered;
3889  SwitchAlwaysHasSuccessor |= Terminator->isAllEnumCasesCovered() &&
3890  Terminator->getSwitchCaseList();
3891  addSuccessor(SwitchTerminatedBlock, DefaultCaseBlock,
3892  !SwitchAlwaysHasSuccessor);
3893 
3894  // Add the terminator and condition in the switch block.
3895  SwitchTerminatedBlock->setTerminator(Terminator);
3896  Block = SwitchTerminatedBlock;
3897  CFGBlock *LastBlock = addStmt(Terminator->getCond());
3898 
3899  // If the SwitchStmt contains a condition variable, add both the
3900  // SwitchStmt and the condition variable initialization to the CFG.
3901  if (VarDecl *VD = Terminator->getConditionVariable()) {
3902  if (Expr *Init = VD->getInit()) {
3903  autoCreateBlock();
3904  appendStmt(Block, Terminator->getConditionVariableDeclStmt());
3905  LastBlock = addStmt(Init);
3906  maybeAddScopeBeginForVarDecl(LastBlock, VD, Init);
3907  }
3908  }
3909 
3910  // Finally, if the SwitchStmt contains a C++17 init-stmt, add it to the CFG.
3911  if (Stmt *Init = Terminator->getInit()) {
3912  autoCreateBlock();
3913  LastBlock = addStmt(Init);
3914  }
3915 
3916  return LastBlock;
3917 }
3918 
3919 static bool shouldAddCase(bool &switchExclusivelyCovered,
3920  const Expr::EvalResult *switchCond,
3921  const CaseStmt *CS,
3922  ASTContext &Ctx) {
3923  if (!switchCond)
3924  return true;
3925 
3926  bool addCase = false;
3927 
3928  if (!switchExclusivelyCovered) {
3929  if (switchCond->Val.isInt()) {
3930  // Evaluate the LHS of the case value.
3931  const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx);
3932  const llvm::APSInt &condInt = switchCond->Val.getInt();
3933 
3934  if (condInt == lhsInt) {
3935  addCase = true;
3936  switchExclusivelyCovered = true;
3937  }
3938  else if (condInt > lhsInt) {
3939  if (const Expr *RHS = CS->getRHS()) {
3940  // Evaluate the RHS of the case value.
3941  const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx);
3942  if (V2 >= condInt) {
3943  addCase = true;
3944  switchExclusivelyCovered = true;
3945  }
3946  }
3947  }
3948  }
3949  else
3950  addCase = true;
3951  }
3952  return addCase;
3953 }
3954 
3955 CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) {
3956  // CaseStmts are essentially labels, so they are the first statement in a
3957  // block.
3958  CFGBlock *TopBlock = nullptr, *LastBlock = nullptr;
3959 
3960  if (Stmt *Sub = CS->getSubStmt()) {
3961  // For deeply nested chains of CaseStmts, instead of doing a recursion
3962  // (which can blow out the stack), manually unroll and create blocks
3963  // along the way.
3964  while (isa<CaseStmt>(Sub)) {
3965  CFGBlock *currentBlock = createBlock(false);
3966  currentBlock->setLabel(CS);
3967 
3968  if (TopBlock)
3969  addSuccessor(LastBlock, currentBlock);
3970  else
3971  TopBlock = currentBlock;
3972 
3973  addSuccessor(SwitchTerminatedBlock,
3974  shouldAddCase(switchExclusivelyCovered, switchCond,
3975  CS, *Context)
3976  ? currentBlock : nullptr);
3977 
3978  LastBlock = currentBlock;
3979  CS = cast<CaseStmt>(Sub);
3980  Sub = CS->getSubStmt();
3981  }
3982 
3983  addStmt(Sub);
3984  }
3985 
3986  CFGBlock *CaseBlock = Block;
3987  if (!CaseBlock)
3988  CaseBlock = createBlock();
3989 
3990  // Cases statements partition blocks, so this is the top of the basic block we
3991  // were processing (the "case XXX:" is the label).
3992  CaseBlock->setLabel(CS);
3993 
3994  if (badCFG)
3995  return nullptr;
3996 
3997  // Add this block to the list of successors for the block with the switch
3998  // statement.
3999  assert(SwitchTerminatedBlock);
4000  addSuccessor(SwitchTerminatedBlock, CaseBlock,
4001  shouldAddCase(switchExclusivelyCovered, switchCond,
4002  CS, *Context));
4003 
4004  // We set Block to NULL to allow lazy creation of a new block (if necessary)
4005  Block = nullptr;
4006 
4007  if (TopBlock) {
4008  addSuccessor(LastBlock, CaseBlock);
4009  Succ = TopBlock;
4010  } else {
4011  // This block is now the implicit successor of other blocks.
4012  Succ = CaseBlock;
4013  }
4014 
4015  return Succ;
4016 }
4017 
4018 CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) {
4019  if (Terminator->getSubStmt())
4020  addStmt(Terminator->getSubStmt());
4021 
4022  DefaultCaseBlock = Block;
4023 
4024  if (!DefaultCaseBlock)
4025  DefaultCaseBlock = createBlock();
4026 
4027  // Default statements partition blocks, so this is the top of the basic block
4028  // we were processing (the "default:" is the label).
4029  DefaultCaseBlock->setLabel(Terminator);
4030 
4031  if (badCFG)
4032  return nullptr;
4033 
4034  // Unlike case statements, we don't add the default block to the successors
4035  // for the switch statement immediately. This is done when we finish
4036  // processing the switch statement. This allows for the default case
4037  // (including a fall-through to the code after the switch statement) to always
4038  // be the last successor of a switch-terminated block.
4039 
4040  // We set Block to NULL to allow lazy creation of a new block (if necessary)
4041  Block = nullptr;
4042 
4043  // This block is now the implicit successor of other blocks.
4044  Succ = DefaultCaseBlock;
4045 
4046  return DefaultCaseBlock;
4047 }
4048 
4049 CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) {
4050  // "try"/"catch" is a control-flow statement. Thus we stop processing the
4051  // current block.
4052  CFGBlock *TrySuccessor = nullptr;
4053 
4054  if (Block) {
4055  if (badCFG)
4056  return nullptr;
4057  TrySuccessor = Block;
4058  } else TrySuccessor = Succ;
4059 
4060  CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock;
4061 
4062  // Create a new block that will contain the try statement.
4063  CFGBlock *NewTryTerminatedBlock = createBlock(false);
4064  // Add the terminator in the try block.
4065  NewTryTerminatedBlock->setTerminator(Terminator);
4066 
4067  bool HasCatchAll = false;
4068  for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) {
4069  // The code after the try is the implicit successor.
4070  Succ = TrySuccessor;
4071  CXXCatchStmt *CS = Terminator->getHandler(h);
4072  if (CS->getExceptionDecl() == nullptr) {
4073  HasCatchAll = true;
4074  }
4075  Block = nullptr;
4076  CFGBlock *CatchBlock = VisitCXXCatchStmt(CS);
4077  if (!CatchBlock)
4078  return nullptr;
4079  // Add this block to the list of successors for the block with the try
4080  // statement.
4081  addSuccessor(NewTryTerminatedBlock, CatchBlock);
4082  }
4083  if (!HasCatchAll) {
4084  if (PrevTryTerminatedBlock)
4085  addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock);
4086  else
4087  addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
4088  }
4089 
4090  // The code after the try is the implicit successor.
4091  Succ = TrySuccessor;
4092 
4093  // Save the current "try" context.
4094  SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock);
4095  cfg->addTryDispatchBlock(TryTerminatedBlock);
4096 
4097  assert(Terminator->getTryBlock() && "try must contain a non-NULL body");
4098  Block = nullptr;
4099  return addStmt(Terminator->getTryBlock());
4100 }
4101 
4102 CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) {
4103  // CXXCatchStmt are treated like labels, so they are the first statement in a
4104  // block.
4105 
4106  // Save local scope position because in case of exception variable ScopePos
4107  // won't be restored when traversing AST.
4108  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
4109 
4110  // Create local scope for possible exception variable.
4111  // Store scope position. Add implicit destructor.
4112  if (VarDecl *VD = CS->getExceptionDecl()) {
4113  LocalScope::const_iterator BeginScopePos = ScopePos;
4114  addLocalScopeForVarDecl(VD);
4115  addAutomaticObjHandling(ScopePos, BeginScopePos, CS);
4116  }
4117 
4118  if (CS->getHandlerBlock())
4119  addStmt(CS->getHandlerBlock());
4120 
4121  CFGBlock *CatchBlock = Block;
4122  if (!CatchBlock)
4123  CatchBlock = createBlock();
4124 
4125  // CXXCatchStmt is more than just a label. They have semantic meaning
4126  // as well, as they implicitly "initialize" the catch variable. Add
4127  // it to the CFG as a CFGElement so that the control-flow of these
4128  // semantics gets captured.
4129  appendStmt(CatchBlock, CS);
4130 
4131  // Also add the CXXCatchStmt as a label, to mirror handling of regular
4132  // labels.
4133  CatchBlock->setLabel(CS);
4134 
4135  // Bail out if the CFG is bad.
4136  if (badCFG)
4137  return nullptr;
4138 
4139  // We set Block to NULL to allow lazy creation of a new block (if necessary)
4140  Block = nullptr;
4141 
4142  return CatchBlock;
4143 }
4144 
4145 CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) {
4146  // C++0x for-range statements are specified as [stmt.ranged]:
4147  //
4148  // {
4149  // auto && __range = range-init;
4150  // for ( auto __begin = begin-expr,
4151  // __end = end-expr;
4152  // __begin != __end;
4153  // ++__begin ) {
4154  // for-range-declaration = *__begin;
4155  // statement
4156  // }
4157  // }
4158 
4159  // Save local scope position before the addition of the implicit variables.
4160  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
4161 
4162  // Create local scopes and destructors for range, begin and end variables.
4163  if (Stmt *Range = S->getRangeStmt())
4164  addLocalScopeForStmt(Range);
4165  if (Stmt *Begin = S->getBeginStmt())
4166  addLocalScopeForStmt(Begin);
4167  if (Stmt *End = S->getEndStmt())
4168  addLocalScopeForStmt(End);
4169  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), S);
4170 
4171  LocalScope::const_iterator ContinueScopePos = ScopePos;
4172 
4173  // "for" is a control-flow statement. Thus we stop processing the current
4174  // block.
4175  CFGBlock *LoopSuccessor = nullptr;
4176  if (Block) {
4177  if (badCFG)
4178  return nullptr;
4179  LoopSuccessor = Block;
4180  } else
4181  LoopSuccessor = Succ;
4182 
4183  // Save the current value for the break targets.
4184  // All breaks should go to the code following the loop.
4185  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
4186  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
4187 
4188  // The block for the __begin != __end expression.
4189  CFGBlock *ConditionBlock = createBlock(false);
4190  ConditionBlock->setTerminator(S);
4191 
4192  // Now add the actual condition to the condition block.
4193  if (Expr *C = S->getCond()) {
4194  Block = ConditionBlock;
4195  CFGBlock *BeginConditionBlock = addStmt(C);
4196  if (badCFG)
4197  return nullptr;
4198  assert(BeginConditionBlock == ConditionBlock &&
4199  "condition block in for-range was unexpectedly complex");
4200  (void)BeginConditionBlock;
4201  }
4202 
4203  // The condition block is the implicit successor for the loop body as well as
4204  // any code above the loop.
4205  Succ = ConditionBlock;
4206 
4207  // See if this is a known constant.
4208  TryResult KnownVal(true);
4209 
4210  if (S->getCond())
4211  KnownVal = tryEvaluateBool(S->getCond());
4212 
4213  // Now create the loop body.
4214  {
4215  assert(S->getBody());
4216 
4217  // Save the current values for Block, Succ, and continue targets.
4218  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
4219  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
4220 
4221  // Generate increment code in its own basic block. This is the target of
4222  // continue statements.
4223  Block = nullptr;
4224  Succ = addStmt(S->getInc());
4225  if (badCFG)
4226  return nullptr;
4227  ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
4228 
4229  // The starting block for the loop increment is the block that should
4230  // represent the 'loop target' for looping back to the start of the loop.
4231  ContinueJumpTarget.block->setLoopTarget(S);
4232 
4233  // Finish up the increment block and prepare to start the loop body.
4234  assert(Block);
4235  if (badCFG)
4236  return nullptr;
4237  Block = nullptr;
4238 
4239  // Add implicit scope and dtors for loop variable.
4240  addLocalScopeAndDtors(S->getLoopVarStmt());
4241 
4242  // Populate a new block to contain the loop body and loop variable.
4243  addStmt(S->getBody());
4244  if (badCFG)
4245  return nullptr;
4246  CFGBlock *LoopVarStmtBlock = addStmt(S->getLoopVarStmt());
4247  if (badCFG)
4248  return nullptr;
4249 
4250  // This new body block is a successor to our condition block.
4251  addSuccessor(ConditionBlock,
4252  KnownVal.isFalse() ? nullptr : LoopVarStmtBlock);
4253  }
4254 
4255  // Link up the condition block with the code that follows the loop (the
4256  // false branch).
4257  addSuccessor(ConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
4258 
4259  // Add the initialization statements.
4260  Block = createBlock();
4261  addStmt(S->getBeginStmt());
4262  addStmt(S->getEndStmt());
4263  CFGBlock *Head = addStmt(S->getRangeStmt());
4264  if (S->getInit())
4265  Head = addStmt(S->getInit());
4266  return Head;
4267 }
4268 
4269 CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E,
4270  AddStmtChoice asc) {
4271  if (BuildOpts.AddTemporaryDtors) {
4272  // If adding implicit destructors visit the full expression for adding
4273  // destructors of temporaries.
4274  TempDtorContext Context;
4275  VisitForTemporaryDtors(E->getSubExpr(), false, Context);
4276 
4277  // Full expression has to be added as CFGStmt so it will be sequenced
4278  // before destructors of it's temporaries.
4279  asc = asc.withAlwaysAdd(true);
4280  }
4281  return Visit(E->getSubExpr(), asc);
4282 }
4283 
4284 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
4285  AddStmtChoice asc) {
4286  if (asc.alwaysAdd(*this, E)) {
4287  autoCreateBlock();
4288  appendStmt(Block, E);
4289 
4290  findConstructionContexts(
4291  ConstructionContextLayer::create(cfg->getBumpVectorContext(), E),
4292  E->getSubExpr());
4293 
4294  // We do not want to propagate the AlwaysAdd property.
4295  asc = asc.withAlwaysAdd(false);
4296  }
4297  return Visit(E->getSubExpr(), asc);
4298 }
4299 
4300 CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C,
4301  AddStmtChoice asc) {
4302  // If the constructor takes objects as arguments by value, we need to properly
4303  // construct these objects. Construction contexts we find here aren't for the
4304  // constructor C, they're for its arguments only.
4305  findConstructionContextsForArguments(C);
4306 
4307  autoCreateBlock();
4308  appendConstructor(Block, C);
4309 
4310  return VisitChildren(C);
4311 }
4312 
4313 CFGBlock *CFGBuilder::VisitCXXNewExpr(CXXNewExpr *NE,
4314  AddStmtChoice asc) {
4315  autoCreateBlock();
4316  appendStmt(Block, NE);
4317 
4318  findConstructionContexts(
4319  ConstructionContextLayer::create(cfg->getBumpVectorContext(), NE),
4320  const_cast<CXXConstructExpr *>(NE->getConstructExpr()));
4321 
4322  if (NE->getInitializer())
4323  Block = Visit(NE->getInitializer());
4324 
4325  if (BuildOpts.AddCXXNewAllocator)
4326  appendNewAllocator(Block, NE);
4327 
4328  if (NE->isArray())
4329  Block = Visit(NE->getArraySize());
4330 
4332  E = NE->placement_arg_end(); I != E; ++I)
4333  Block = Visit(*I);
4334 
4335  return Block;
4336 }
4337 
4338 CFGBlock *CFGBuilder::VisitCXXDeleteExpr(CXXDeleteExpr *DE,
4339  AddStmtChoice asc) {
4340  autoCreateBlock();
4341  appendStmt(Block, DE);
4342  QualType DTy = DE->getDestroyedType();
4343  if (!DTy.isNull()) {
4344  DTy = DTy.getNonReferenceType();
4345  CXXRecordDecl *RD = Context->getBaseElementType(DTy)->getAsCXXRecordDecl();
4346  if (RD) {
4347  if (RD->isCompleteDefinition() && !RD->hasTrivialDestructor())
4348  appendDeleteDtor(Block, RD, DE);
4349  }
4350  }
4351 
4352  return VisitChildren(DE);
4353 }
4354 
4355 CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
4356  AddStmtChoice asc) {
4357  if (asc.alwaysAdd(*this, E)) {
4358  autoCreateBlock();
4359  appendStmt(Block, E);
4360  // We do not want to propagate the AlwaysAdd property.
4361  asc = asc.withAlwaysAdd(false);
4362  }
4363  return Visit(E->getSubExpr(), asc);
4364 }
4365 
4366 CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
4367  AddStmtChoice asc) {
4368  // If the constructor takes objects as arguments by value, we need to properly
4369  // construct these objects. Construction contexts we find here aren't for the
4370  // constructor C, they're for its arguments only.
4371  findConstructionContextsForArguments(C);
4372 
4373  autoCreateBlock();
4374  appendConstructor(Block, C);
4375  return VisitChildren(C);
4376 }
4377 
4378 CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E,
4379  AddStmtChoice asc) {
4380  if (asc.alwaysAdd(*this, E)) {
4381  autoCreateBlock();
4382  appendStmt(Block, E);
4383  }
4384  return Visit(E->getSubExpr(), AddStmtChoice());
4385 }
4386 
4387 CFGBlock *CFGBuilder::VisitConstantExpr(ConstantExpr *E, AddStmtChoice asc) {
4388  return Visit(E->getSubExpr(), AddStmtChoice());
4389 }
4390 
4391 CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) {
4392  // Lazily create the indirect-goto dispatch block if there isn't one already.
4393  CFGBlock *IBlock = cfg->getIndirectGotoBlock();
4394 
4395  if (!IBlock) {
4396  IBlock = createBlock(false);
4397  cfg->setIndirectGotoBlock(IBlock);
4398  }
4399 
4400  // IndirectGoto is a control-flow statement. Thus we stop processing the
4401  // current block and create a new one.
4402  if (badCFG)
4403  return nullptr;
4404 
4405  Block = createBlock(false);
4406  Block->setTerminator(I);
4407  addSuccessor(Block, IBlock);
4408  return addStmt(I->getTarget());
4409 }
4410 
4411 CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary,
4412  TempDtorContext &Context) {
4413  assert(BuildOpts.AddImplicitDtors && BuildOpts.AddTemporaryDtors);
4414 
4415 tryAgain:
4416  if (!E) {
4417  badCFG = true;
4418  return nullptr;
4419  }
4420  switch (E->getStmtClass()) {
4421  default:
4422  return VisitChildrenForTemporaryDtors(E, Context);
4423 
4424  case Stmt::BinaryOperatorClass:
4425  return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E),
4426  Context);
4427 
4428  case Stmt::CXXBindTemporaryExprClass:
4429  return VisitCXXBindTemporaryExprForTemporaryDtors(
4430  cast<CXXBindTemporaryExpr>(E), BindToTemporary, Context);
4431 
4432  case Stmt::BinaryConditionalOperatorClass:
4433  case Stmt::ConditionalOperatorClass:
4434  return VisitConditionalOperatorForTemporaryDtors(
4435  cast<AbstractConditionalOperator>(E), BindToTemporary, Context);
4436 
4437  case Stmt::ImplicitCastExprClass:
4438  // For implicit cast we want BindToTemporary to be passed further.
4439  E = cast<CastExpr>(E)->getSubExpr();
4440  goto tryAgain;
4441 
4442  case Stmt::CXXFunctionalCastExprClass:
4443  // For functional cast we want BindToTemporary to be passed further.
4444  E = cast<CXXFunctionalCastExpr>(E)->getSubExpr();
4445  goto tryAgain;
4446 
4447  case Stmt::ConstantExprClass:
4448  E = cast<ConstantExpr>(E)->getSubExpr();
4449  goto tryAgain;
4450 
4451  case Stmt::ParenExprClass:
4452  E = cast<ParenExpr>(E)->getSubExpr();
4453  goto tryAgain;
4454 
4455  case Stmt::MaterializeTemporaryExprClass: {
4456  const MaterializeTemporaryExpr* MTE = cast<MaterializeTemporaryExpr>(E);
4457  BindToTemporary = (MTE->getStorageDuration() != SD_FullExpression);
4458  SmallVector<const Expr *, 2> CommaLHSs;
4460  // Find the expression whose lifetime needs to be extended.
4461  E = const_cast<Expr *>(
4462  cast<MaterializeTemporaryExpr>(E)
4463  ->GetTemporaryExpr()
4464  ->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments));
4465  // Visit the skipped comma operator left-hand sides for other temporaries.
4466  for (const Expr *CommaLHS : CommaLHSs) {
4467  VisitForTemporaryDtors(const_cast<Expr *>(CommaLHS),
4468  /*BindToTemporary=*/false, Context);
4469  }
4470  goto tryAgain;
4471  }
4472 
4473  case Stmt::BlockExprClass:
4474  // Don't recurse into blocks; their subexpressions don't get evaluated
4475  // here.
4476  return Block;
4477 
4478  case Stmt::LambdaExprClass: {
4479  // For lambda expressions, only recurse into the capture initializers,
4480  // and not the body.
4481  auto *LE = cast<LambdaExpr>(E);
4482  CFGBlock *B = Block;
4483  for (Expr *Init : LE->capture_inits()) {
4484  if (Init) {
4485  if (CFGBlock *R = VisitForTemporaryDtors(
4486  Init, /*BindToTemporary=*/false, Context))
4487  B = R;
4488  }
4489  }
4490  return B;
4491  }
4492 
4493  case Stmt::CXXDefaultArgExprClass:
4494  E = cast<CXXDefaultArgExpr>(E)->getExpr();
4495  goto tryAgain;
4496 
4497  case Stmt::CXXDefaultInitExprClass:
4498  E = cast<CXXDefaultInitExpr>(E)->getExpr();
4499  goto tryAgain;
4500  }
4501 }
4502 
4503 CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E,
4504  TempDtorContext &Context) {
4505  if (isa<LambdaExpr>(E)) {
4506  // Do not visit the children of lambdas; they have their own CFGs.
4507  return Block;
4508  }
4509 
4510  // When visiting children for destructors we want to visit them in reverse
4511  // order that they will appear in the CFG. Because the CFG is built
4512  // bottom-up, this means we visit them in their natural order, which
4513  // reverses them in the CFG.
4514  CFGBlock *B = Block;
4515  for (Stmt *Child : E->children())
4516  if (Child)
4517  if (CFGBlock *R = VisitForTemporaryDtors(Child, false, Context))
4518  B = R;
4519 
4520  return B;
4521 }
4522 
4523 CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(
4524  BinaryOperator *E, TempDtorContext &Context) {
4525  if (E->isLogicalOp()) {
4526  VisitForTemporaryDtors(E->getLHS(), false, Context);
4527  TryResult RHSExecuted = tryEvaluateBool(E->getLHS());
4528  if (RHSExecuted.isKnown() && E->getOpcode() == BO_LOr)
4529  RHSExecuted.negate();
4530 
4531  // We do not know at CFG-construction time whether the right-hand-side was
4532  // executed, thus we add a branch node that depends on the temporary
4533  // constructor call.
4534  TempDtorContext RHSContext(
4535  bothKnownTrue(Context.KnownExecuted, RHSExecuted));
4536  VisitForTemporaryDtors(E->getRHS(), false, RHSContext);
4537  InsertTempDtorDecisionBlock(RHSContext);
4538 
4539  return Block;
4540  }
4541 
4542  if (E->isAssignmentOp()) {
4543  // For assignment operator (=) LHS expression is visited
4544  // before RHS expression. For destructors visit them in reverse order.
4545  CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
4546  CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
4547  return LHSBlock ? LHSBlock : RHSBlock;
4548  }
4549 
4550  // For any other binary operator RHS expression is visited before
4551  // LHS expression (order of children). For destructors visit them in reverse
4552  // order.
4553  CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
4554  CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
4555  return RHSBlock ? RHSBlock : LHSBlock;
4556 }
4557 
4558 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors(
4559  CXXBindTemporaryExpr *E, bool BindToTemporary, TempDtorContext &Context) {
4560  // First add destructors for temporaries in subexpression.
4561  CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr(), false, Context);
4562  if (!BindToTemporary) {
4563  // If lifetime of temporary is not prolonged (by assigning to constant
4564  // reference) add destructor for it.
4565 
4566  const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor();
4567 
4568  if (Dtor->getParent()->isAnyDestructorNoReturn()) {
4569  // If the destructor is marked as a no-return destructor, we need to
4570  // create a new block for the destructor which does not have as a
4571  // successor anything built thus far. Control won't flow out of this
4572  // block.
4573  if (B) Succ = B;
4574  Block = createNoReturnBlock();
4575  } else if (Context.needsTempDtorBranch()) {
4576  // If we need to introduce a branch, we add a new block that we will hook
4577  // up to a decision block later.
4578  if (B) Succ = B;
4579  Block = createBlock();
4580  } else {
4581  autoCreateBlock();
4582  }
4583  if (Context.needsTempDtorBranch()) {
4584  Context.setDecisionPoint(Succ, E);
4585  }
4586  appendTemporaryDtor(Block, E);
4587 
4588  B = Block;
4589  }
4590  return B;
4591 }
4592 
4593 void CFGBuilder::InsertTempDtorDecisionBlock(const TempDtorContext &Context,
4594  CFGBlock *FalseSucc) {
4595  if (!Context.TerminatorExpr) {
4596  // If no temporary was found, we do not need to insert a decision point.
4597  return;
4598  }
4599  assert(Context.TerminatorExpr);
4600  CFGBlock *Decision = createBlock(false);
4601  Decision->setTerminator(CFGTerminator(Context.TerminatorExpr, true));
4602  addSuccessor(Decision, Block, !Context.KnownExecuted.isFalse());
4603  addSuccessor(Decision, FalseSucc ? FalseSucc : Context.Succ,
4604  !Context.KnownExecuted.isTrue());
4605  Block = Decision;
4606 }
4607 
4608 CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors(
4609  AbstractConditionalOperator *E, bool BindToTemporary,
4610  TempDtorContext &Context) {
4611  VisitForTemporaryDtors(E->getCond(), false, Context);
4612  CFGBlock *ConditionBlock = Block;
4613  CFGBlock *ConditionSucc = Succ;
4614  TryResult ConditionVal = tryEvaluateBool(E->getCond());
4615  TryResult NegatedVal = ConditionVal;
4616  if (NegatedVal.isKnown()) NegatedVal.negate();
4617 
4618  TempDtorContext TrueContext(
4619  bothKnownTrue(Context.KnownExecuted, ConditionVal));
4620  VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary, TrueContext);
4621  CFGBlock *TrueBlock = Block;
4622 
4623  Block = ConditionBlock;
4624  Succ = ConditionSucc;
4625  TempDtorContext FalseContext(
4626  bothKnownTrue(Context.KnownExecuted, NegatedVal));
4627  VisitForTemporaryDtors(E->getFalseExpr(), BindToTemporary, FalseContext);
4628 
4629  if (TrueContext.TerminatorExpr && FalseContext.TerminatorExpr) {
4630  InsertTempDtorDecisionBlock(FalseContext, TrueBlock);
4631  } else if (TrueContext.TerminatorExpr) {
4632  Block = TrueBlock;
4633  InsertTempDtorDecisionBlock(TrueContext);
4634  } else {
4635  InsertTempDtorDecisionBlock(FalseContext);
4636  }
4637  return Block;
4638 }
4639 
4640 /// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has
4641 /// no successors or predecessors. If this is the first block created in the
4642 /// CFG, it is automatically set to be the Entry and Exit of the CFG.
4644  bool first_block = begin() == end();
4645 
4646  // Create the block.
4647  CFGBlock *Mem = getAllocator().Allocate<CFGBlock>();
4648  new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this);
4649  Blocks.push_back(Mem, BlkBVC);
4650 
4651  // If this is the first block, set it as the Entry and Exit.
4652  if (first_block)
4653  Entry = Exit = &back();
4654 
4655  // Return the block.
4656  return &back();
4657 }
4658 
4659 /// buildCFG - Constructs a CFG from an AST.
4660 std::unique_ptr<CFG> CFG::buildCFG(const Decl *D, Stmt *Statement,
4661  ASTContext *C, const BuildOptions &BO) {
4662  CFGBuilder Builder(C, BO);
4663  return Builder.buildCFG(D, Statement);
4664 }
4665 
4666 const CXXDestructorDecl *
4668  switch (getKind()) {
4671  case CFGElement::LoopExit:
4673  case CFGElement::Statement:
4677  case CFGElement::ScopeEnd:
4678  llvm_unreachable("getDestructorDecl should only be used with "
4679  "ImplicitDtors");
4681  const VarDecl *var = castAs<CFGAutomaticObjDtor>().getVarDecl();
4682  QualType ty = var->getType();
4683 
4684  // FIXME: See CFGBuilder::addLocalScopeForVarDecl.
4685  //
4686  // Lifetime-extending constructs are handled here. This works for a single
4687  // temporary in an initializer expression.
4688  if (ty->isReferenceType()) {
4689  if (const Expr *Init = var->getInit()) {
4690  ty = getReferenceInitTemporaryType(Init);
4691  }
4692  }
4693 
4694  while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) {
4695  ty = arrayType->getElementType();
4696  }
4697  const RecordType *recordType = ty->getAs<RecordType>();
4698  const CXXRecordDecl *classDecl =
4699  cast<CXXRecordDecl>(recordType->getDecl());
4700  return classDecl->getDestructor();
4701  }
4702  case CFGElement::DeleteDtor: {
4703  const CXXDeleteExpr *DE = castAs<CFGDeleteDtor>().getDeleteExpr();
4704  QualType DTy = DE->getDestroyedType();
4705  DTy = DTy.getNonReferenceType();
4706  const CXXRecordDecl *classDecl =
4707  astContext.getBaseElementType(DTy)->getAsCXXRecordDecl();
4708  return classDecl->getDestructor();
4709  }
4711  const CXXBindTemporaryExpr *bindExpr =
4712  castAs<CFGTemporaryDtor>().getBindTemporaryExpr();
4713  const CXXTemporary *temp = bindExpr->getTemporary();
4714  return temp->getDestructor();
4715  }
4716  case CFGElement::BaseDtor:
4718  // Not yet supported.
4719  return nullptr;
4720  }
4721  llvm_unreachable("getKind() returned bogus value");
4722 }
4723 
4724 bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const {
4725  if (const CXXDestructorDecl *DD = getDestructorDecl(astContext))
4726  return DD->isNoReturn();
4727  return false;
4728 }
4729 
4730 //===----------------------------------------------------------------------===//
4731 // CFGBlock operations.
4732 //===----------------------------------------------------------------------===//
4733 
4735  : ReachableBlock(IsReachable ? B : nullptr),
4736  UnreachableBlock(!IsReachable ? B : nullptr,
4737  B && IsReachable ? AB_Normal : AB_Unreachable) {}
4738 
4740  : ReachableBlock(B),
4741  UnreachableBlock(B == AlternateBlock ? nullptr : AlternateBlock,
4742  B == AlternateBlock ? AB_Alternate : AB_Normal) {}
4743 
4745  BumpVectorContext &C) {
4746  if (CFGBlock *B = Succ.getReachableBlock())
4747  B->Preds.push_back(AdjacentBlock(this, Succ.isReachable()), C);
4748 
4749  if (CFGBlock *UnreachableB = Succ.getPossiblyUnreachableBlock())
4750  UnreachableB->Preds.push_back(AdjacentBlock(this, false), C);
4751 
4752  Succs.push_back(Succ, C);
4753 }
4754 
4756  const CFGBlock *From, const CFGBlock *To) {
4757  if (F.IgnoreNullPredecessors && !From)
4758  return true;
4759 
4760  if (To && From && F.IgnoreDefaultsWithCoveredEnums) {
4761  // If the 'To' has no label or is labeled but the label isn't a
4762  // CaseStmt then filter this edge.
4763  if (const SwitchStmt *S =
4764  dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) {
4765  if (S->isAllEnumCasesCovered()) {
4766  const Stmt *L = To->getLabel();
4767  if (!L || !isa<CaseStmt>(L))
4768  return true;
4769  }
4770  }
4771  }
4772 
4773  return false;
4774 }
4775 
4776 //===----------------------------------------------------------------------===//
4777 // CFG pretty printing
4778 //===----------------------------------------------------------------------===//
4779 
4780 namespace {
4781 
4782 class StmtPrinterHelper : public PrinterHelper {
4783  using StmtMapTy = llvm::DenseMap<const Stmt *, std::pair<unsigned, unsigned>>;
4784  using DeclMapTy = llvm::DenseMap<const Decl *, std::pair<unsigned, unsigned>>;
4785 
4786  StmtMapTy StmtMap;
4787  DeclMapTy DeclMap;
4788  signed currentBlock = 0;
4789  unsigned currStmt = 0;
4790  const LangOptions &LangOpts;
4791 
4792 public:
4793  StmtPrinterHelper(const CFG* cfg, const LangOptions &LO)
4794  : LangOpts(LO) {
4795  for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) {
4796  unsigned j = 1;
4797  for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ;
4798  BI != BEnd; ++BI, ++j ) {
4799  if (Optional<CFGStmt> SE = BI->getAs<CFGStmt>()) {
4800  const Stmt *stmt= SE->getStmt();
4801  std::pair<unsigned, unsigned> P((*I)->getBlockID(), j);
4802  StmtMap[stmt] = P;
4803 
4804  switch (stmt->getStmtClass()) {
4805  case Stmt::DeclStmtClass:
4806  DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P;
4807  break;
4808  case Stmt::IfStmtClass: {
4809  const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable();
4810  if (var)
4811  DeclMap[var] = P;
4812  break;
4813  }
4814  case Stmt::ForStmtClass: {
4815  const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable();
4816  if (var)
4817  DeclMap[var] = P;
4818  break;
4819  }
4820  case Stmt::WhileStmtClass: {
4821  const VarDecl *var =
4822  cast<WhileStmt>(stmt)->getConditionVariable();
4823  if (var)
4824  DeclMap[var] = P;
4825  break;
4826  }
4827  case Stmt::SwitchStmtClass: {
4828  const VarDecl *var =
4829  cast<SwitchStmt>(stmt)->getConditionVariable();
4830  if (var)
4831  DeclMap[var] = P;
4832  break;
4833  }
4834  case Stmt::CXXCatchStmtClass: {
4835  const VarDecl *var =
4836  cast<CXXCatchStmt>(stmt)->getExceptionDecl();
4837  if (var)
4838  DeclMap[var] = P;
4839  break;
4840  }
4841  default:
4842  break;
4843  }
4844  }
4845  }
4846  }
4847  }
4848 
4849  ~StmtPrinterHelper() override = default;
4850 
4851  const LangOptions &getLangOpts() const { return LangOpts; }
4852  void setBlockID(signed i) { currentBlock = i; }
4853  void setStmtID(unsigned i) { currStmt = i; }
4854 
4855  bool handledStmt(Stmt *S, raw_ostream &OS) override {
4856  StmtMapTy::iterator I = StmtMap.find(S);
4857 
4858  if (I == StmtMap.end())
4859  return false;
4860 
4861  if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
4862  && I->second.second == currStmt) {
4863  return false;
4864  }
4865 
4866  OS << "[B" << I->second.first << "." << I->second.second << "]";
4867  return true;
4868  }
4869 
4870  bool handleDecl(const Decl *D, raw_ostream &OS) {
4871  DeclMapTy::iterator I = DeclMap.find(D);
4872 
4873  if (I == DeclMap.end())
4874  return false;
4875 
4876  if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
4877  && I->second.second == currStmt) {
4878  return false;
4879  }
4880 
4881  OS << "[B" << I->second.first << "." << I->second.second << "]";
4882  return true;
4883  }
4884 };
4885 
4886 class CFGBlockTerminatorPrint
4887  : public StmtVisitor<CFGBlockTerminatorPrint,void> {
4888  raw_ostream &OS;
4889  StmtPrinterHelper* Helper;
4890  PrintingPolicy Policy;
4891 
4892 public:
4893  CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper,
4894  const PrintingPolicy &Policy)
4895  : OS(os), Helper(helper), Policy(Policy) {
4896  this->Policy.IncludeNewlines = false;
4897  }
4898 
4899  void VisitIfStmt(IfStmt *I) {
4900  OS << "if ";
4901  if (Stmt *C = I->getCond())
4902  C->printPretty(OS, Helper, Policy);
4903  }
4904 
4905  // Default case.
4906  void VisitStmt(Stmt *Terminator) {
4907  Terminator->printPretty(OS, Helper, Policy);
4908  }
4909 
4910  void VisitDeclStmt(DeclStmt *DS) {
4911  VarDecl *VD = cast<VarDecl>(DS->getSingleDecl());
4912  OS << "static init " << VD->getName();
4913  }
4914 
4915  void VisitForStmt(ForStmt *F) {
4916  OS << "for (" ;
4917  if (F->getInit())
4918  OS << "...";
4919  OS << "; ";
4920  if (Stmt *C = F->getCond())
4921  C->printPretty(OS, Helper, Policy);
4922  OS << "; ";
4923  if (F->getInc())
4924  OS << "...";
4925  OS << ")";
4926  }
4927 
4928  void VisitWhileStmt(WhileStmt *W) {
4929  OS << "while " ;
4930  if (Stmt *C = W->getCond())
4931  C->printPretty(OS, Helper, Policy);
4932  }
4933 
4934  void VisitDoStmt(DoStmt *D) {
4935  OS << "do ... while ";
4936  if (Stmt *C = D->getCond())
4937  C->printPretty(OS, Helper, Policy);
4938  }
4939 
4940  void VisitSwitchStmt(SwitchStmt *Terminator) {
4941  OS << "switch ";
4942  Terminator->getCond()->printPretty(OS, Helper, Policy);
4943  }
4944 
4945  void VisitCXXTryStmt(CXXTryStmt *CS) {
4946  OS << "try ...";
4947  }
4948 
4949  void VisitSEHTryStmt(SEHTryStmt *CS) {
4950  OS << "__try ...";
4951  }
4952 
4953  void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) {
4954  if (Stmt *Cond = C->getCond())
4955  Cond->printPretty(OS, Helper, Policy);
4956  OS << " ? ... : ...";
4957  }
4958 
4959  void VisitChooseExpr(ChooseExpr *C) {
4960  OS << "__builtin_choose_expr( ";
4961  if (Stmt *Cond = C->getCond())
4962  Cond->printPretty(OS, Helper, Policy);
4963  OS << " )";
4964  }
4965 
4966  void VisitIndirectGotoStmt(IndirectGotoStmt *I) {
4967  OS << "goto *";
4968  if (Stmt *T = I->getTarget())
4969  T->printPretty(OS, Helper, Policy);
4970  }
4971 
4972  void VisitBinaryOperator(BinaryOperator* B) {
4973  if (!B->isLogicalOp()) {
4974  VisitExpr(B);
4975  return;
4976  }
4977 
4978  if (B->getLHS())
4979  B->getLHS()->printPretty(OS, Helper, Policy);
4980 
4981  switch (B->getOpcode()) {
4982  case BO_LOr:
4983  OS << " || ...";
4984  return;
4985  case BO_LAnd:
4986  OS << " && ...";
4987  return;
4988  default:
4989  llvm_unreachable("Invalid logical operator.");
4990  }
4991  }
4992 
4993  void VisitExpr(Expr *E) {
4994  E->printPretty(OS, Helper, Policy);
4995  }
4996 
4997 public:
4998  void print(CFGTerminator T) {
4999  if (T.isTemporaryDtorsBranch())
5000  OS << "(Temp Dtor) ";
5001  Visit(T.getStmt());
5002  }
5003 };
5004 
5005 } // namespace
5006 
5007 static void print_initializer(raw_ostream &OS, StmtPrinterHelper &Helper,
5008  const CXXCtorInitializer *I) {
5009  if (I->isBaseInitializer())
5010  OS << I->getBaseClass()->getAsCXXRecordDecl()->getName();
5011  else if (I->isDelegatingInitializer())
5013  else
5014  OS << I->getAnyMember()->getName();
5015  OS << "(";
5016  if (Expr *IE = I->getInit())
5017  IE->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
5018  OS << ")";
5019 
5020  if (I->isBaseInitializer())
5021  OS << " (Base initializer)";
5022  else if (I->isDelegatingInitializer())
5023  OS << " (Delegating initializer)";
5024  else
5025  OS << " (Member initializer)";
5026 }
5027 
5028 static void print_construction_context(raw_ostream &OS,
5029  StmtPrinterHelper &Helper,
5030  const ConstructionContext *CC) {
5032  switch (CC->getKind()) {
5034  OS << ", ";
5035  const auto *SICC = cast<SimpleConstructorInitializerConstructionContext>(CC);
5036  print_initializer(OS, Helper, SICC->getCXXCtorInitializer());
5037  return;
5038  }
5040  OS << ", ";
5041  const auto *CICC =
5042  cast<CXX17ElidedCopyConstructorInitializerConstructionContext>(CC);
5043  print_initializer(OS, Helper, CICC->getCXXCtorInitializer());
5044  Stmts.push_back(CICC->getCXXBindTemporaryExpr());
5045  break;
5046  }
5048  const auto *SDSCC = cast<SimpleVariableConstructionContext>(CC);
5049  Stmts.push_back(SDSCC->getDeclStmt());
5050  break;
5051  }
5053  const auto *CDSCC = cast<CXX17ElidedCopyVariableConstructionContext>(CC);
5054  Stmts.push_back(CDSCC->getDeclStmt());
5055  Stmts.push_back(CDSCC->getCXXBindTemporaryExpr());
5056  break;
5057  }
5059  const auto *NECC = cast<NewAllocatedObjectConstructionContext>(CC);
5060  Stmts.push_back(NECC->getCXXNewExpr());
5061  break;
5062  }
5064  const auto *RSCC = cast<SimpleReturnedValueConstructionContext>(CC);
5065  Stmts.push_back(RSCC->getReturnStmt());
5066  break;
5067  }
5069  const auto *RSCC =
5070  cast<CXX17ElidedCopyReturnedValueConstructionContext>(CC);
5071  Stmts.push_back(RSCC->getReturnStmt());
5072  Stmts.push_back(RSCC->getCXXBindTemporaryExpr());
5073  break;
5074  }
5076  const auto *TOCC = cast<SimpleTemporaryObjectConstructionContext>(CC);
5077  Stmts.push_back(TOCC->getCXXBindTemporaryExpr());
5078  Stmts.push_back(TOCC->getMaterializedTemporaryExpr());
5079  break;
5080  }
5082  const auto *TOCC = cast<ElidedTemporaryObjectConstructionContext>(CC);
5083  Stmts.push_back(TOCC->getCXXBindTemporaryExpr());
5084  Stmts.push_back(TOCC->getMaterializedTemporaryExpr());
5085  Stmts.push_back(TOCC->getConstructorAfterElision());
5086  break;
5087  }
5089  const auto *ACC = cast<ArgumentConstructionContext>(CC);
5090  if (const Stmt *BTE = ACC->getCXXBindTemporaryExpr()) {
5091  OS << ", ";
5092  Helper.handledStmt(const_cast<Stmt *>(BTE), OS);
5093  }
5094  OS << ", ";
5095  Helper.handledStmt(const_cast<Expr *>(ACC->getCallLikeExpr()), OS);
5096  OS << "+" << ACC->getIndex();
5097  return;
5098  }
5099  }
5100  for (auto I: Stmts)
5101  if (I) {
5102  OS << ", ";
5103  Helper.handledStmt(const_cast<Stmt *>(I), OS);
5104  }
5105 }
5106 
5107 static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
5108  const CFGElement &E) {
5109  if (Optional<CFGStmt> CS = E.getAs<CFGStmt>()) {
5110  const Stmt *S = CS->getStmt();
5111  assert(S != nullptr && "Expecting non-null Stmt");
5112 
5113  // special printing for statement-expressions.
5114  if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) {
5115  const CompoundStmt *Sub = SE->getSubStmt();
5116 
5117  auto Children = Sub->children();
5118  if (Children.begin() != Children.end()) {
5119  OS << "({ ... ; ";
5120  Helper.handledStmt(*SE->getSubStmt()->body_rbegin(),OS);
5121  OS << " })\n";
5122  return;
5123  }
5124  }
5125  // special printing for comma expressions.
5126  if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) {
5127  if (B->getOpcode() == BO_Comma) {
5128  OS << "... , ";
5129  Helper.handledStmt(B->getRHS(),OS);
5130  OS << '\n';
5131  return;
5132  }
5133  }
5134  S->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
5135 
5136  if (auto VTC = E.getAs<CFGCXXRecordTypedCall>()) {
5137  if (isa<CXXOperatorCallExpr>(S))
5138  OS << " (OperatorCall)";
5139  OS << " (CXXRecordTypedCall";
5140  print_construction_context(OS, Helper, VTC->getConstructionContext());
5141  OS << ")";
5142  } else if (isa<CXXOperatorCallExpr>(S)) {
5143  OS << " (OperatorCall)";
5144  } else if (isa<CXXBindTemporaryExpr>(S)) {
5145  OS << " (BindTemporary)";
5146  } else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) {
5147  OS << " (CXXConstructExpr";
5149  print_construction_context(OS, Helper, CE->getConstructionContext());
5150  }
5151  OS << ", " << CCE->getType().getAsString() << ")";
5152  } else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) {
5153  OS << " (" << CE->getStmtClassName() << ", "
5154  << CE->getCastKindName()
5155  << ", " << CE->getType().getAsString()
5156  << ")";
5157  }
5158 
5159  // Expressions need a newline.
5160  if (isa<Expr>(S))
5161  OS << '\n';
5162  } else if (Optional<CFGInitializer> IE = E.getAs<CFGInitializer>()) {
5163  print_initializer(OS, Helper, IE->getInitializer());
5164  OS << '\n';
5165  } else if (Optional<CFGAutomaticObjDtor> DE =
5166  E.getAs<CFGAutomaticObjDtor>()) {
5167  const VarDecl *VD = DE->getVarDecl();
5168  Helper.handleDecl(VD, OS);
5169 
5170  ASTContext &ACtx = VD->getASTContext();
5171  QualType T = VD->getType();
5172  if (T->isReferenceType())
5173  T = getReferenceInitTemporaryType(VD->getInit(), nullptr);
5174  if (const ArrayType *AT = ACtx.getAsArrayType(T))
5175  T = ACtx.getBaseElementType(AT);
5176 
5177  OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()";
5178  OS << " (Implicit destructor)\n";
5179  } else if (Optional<CFGLifetimeEnds> DE = E.getAs<CFGLifetimeEnds>()) {
5180  const VarDecl *VD = DE->getVarDecl();
5181  Helper.handleDecl(VD, OS);
5182 
5183  OS << " (Lifetime ends)\n";
5184  } else if (Optional<CFGLoopExit> LE = E.getAs<CFGLoopExit>()) {
5185  const Stmt *LoopStmt = LE->getLoopStmt();
5186  OS << LoopStmt->getStmtClassName() << " (LoopExit)\n";
5187  } else if (Optional<CFGScopeBegin> SB = E.getAs<CFGScopeBegin>()) {
5188  OS << "CFGScopeBegin(";
5189  if (const VarDecl *VD = SB->getVarDecl())
5190  OS << VD->getQualifiedNameAsString();
5191  OS << ")\n";
5192  } else if (Optional<CFGScopeEnd> SE = E.getAs<CFGScopeEnd>()) {
5193  OS << "CFGScopeEnd(";
5194  if (const VarDecl *VD = SE->getVarDecl())
5195  OS << VD->getQualifiedNameAsString();
5196  OS << ")\n";
5197  } else if (Optional<CFGNewAllocator> NE = E.getAs<CFGNewAllocator>()) {
5198  OS << "CFGNewAllocator(";
5199  if (const CXXNewExpr *AllocExpr = NE->getAllocatorExpr())
5200  AllocExpr->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
5201  OS << ")\n";
5202  } else if (Optional<CFGDeleteDtor> DE = E.getAs<CFGDeleteDtor>()) {
5203  const CXXRecordDecl *RD = DE->getCXXRecordDecl();
5204  if (!RD)
5205  return;
5206  CXXDeleteExpr *DelExpr =
5207  const_cast<CXXDeleteExpr*>(DE->getDeleteExpr());
5208  Helper.handledStmt(cast<Stmt>(DelExpr->getArgument()), OS);
5209  OS << "->~" << RD->getName().str() << "()";
5210  OS << " (Implicit destructor)\n";
5211  } else if (Optional<CFGBaseDtor> BE = E.getAs<CFGBaseDtor>()) {
5212  const CXXBaseSpecifier *BS = BE->getBaseSpecifier();
5213  OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()";
5214  OS << " (Base object destructor)\n";
5215  } else if (Optional<CFGMemberDtor> ME = E.getAs<CFGMemberDtor>()) {
5216  const FieldDecl *FD = ME->getFieldDecl();
5217  const Type *T = FD->getType()->getBaseElementTypeUnsafe();
5218  OS << "this->" << FD->getName();
5219  OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()";
5220  OS << " (Member object destructor)\n";
5221  } else if (Optional<CFGTemporaryDtor> TE = E.getAs<CFGTemporaryDtor>()) {
5222  const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr();
5223  OS << "~";
5224  BT->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
5225  OS << "() (Temporary object destructor)\n";
5226  }
5227 }
5228 
5229 static void print_block(raw_ostream &OS, const CFG* cfg,
5230  const CFGBlock &B,
5231  StmtPrinterHelper &Helper, bool print_edges,
5232  bool ShowColors) {
5233  Helper.setBlockID(B.getBlockID());
5234 
5235  // Print the header.
5236  if (ShowColors)
5237  OS.changeColor(raw_ostream::YELLOW, true);
5238 
5239  OS << "\n [B" << B.getBlockID();
5240 
5241  if (&B == &cfg->getEntry())
5242  OS << " (ENTRY)]\n";
5243  else if (&B == &cfg->getExit())
5244  OS << " (EXIT)]\n";
5245  else if (&B == cfg->getIndirectGotoBlock())
5246  OS << " (INDIRECT GOTO DISPATCH)]\n";
5247  else if (B.hasNoReturnElement())
5248  OS << " (NORETURN)]\n";
5249  else
5250  OS << "]\n";
5251 
5252  if (ShowColors)
5253  OS.resetColor();
5254 
5255  // Print the label of this block.
5256  if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) {
5257  if (print_edges)
5258  OS << " ";
5259 
5260  if (LabelStmt *L = dyn_cast<LabelStmt>(Label))
5261  OS << L->getName();
5262  else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) {
5263  OS << "case ";
5264  if (C->getLHS())
5265  C->getLHS()->printPretty(OS, &Helper,
5266  PrintingPolicy(Helper.getLangOpts()));
5267  if (C->getRHS()) {
5268  OS << " ... ";
5269  C->getRHS()->printPretty(OS, &Helper,
5270  PrintingPolicy(Helper.getLangOpts()));
5271  }
5272  } else if (isa<DefaultStmt>(Label))
5273  OS << "default";
5274  else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) {
5275  OS << "catch (";
5276  if (CS->getExceptionDecl())
5277  CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper.getLangOpts()),
5278  0);
5279  else
5280  OS << "...";
5281  OS << ")";
5282  } else if (SEHExceptStmt *ES = dyn_cast<SEHExceptStmt>(Label)) {
5283  OS << "__except (";
5284  ES->getFilterExpr()->printPretty(OS, &Helper,
5285  PrintingPolicy(Helper.getLangOpts()), 0);
5286  OS << ")";
5287  } else
5288  llvm_unreachable("Invalid label statement in CFGBlock.");
5289 
5290  OS << ":\n";
5291  }
5292 
5293  // Iterate through the statements in the block and print them.
5294  unsigned j = 1;
5295 
5296  for (CFGBlock::const_iterator I = B.begin(), E = B.end() ;
5297  I != E ; ++I, ++j ) {
5298  // Print the statement # in the basic block and the statement itself.
5299  if (print_edges)
5300  OS << " ";
5301 
5302  OS << llvm::format("%3d", j) << ": ";
5303 
5304  Helper.setStmtID(j);
5305 
5306  print_elem(OS, Helper, *I);
5307  }
5308 
5309  // Print the terminator of this block.
5310  if (B.getTerminator()) {
5311  if (ShowColors)
5312  OS.changeColor(raw_ostream::GREEN);
5313 
5314  OS << " T: ";
5315 
5316  Helper.setBlockID(-1);
5317 
5318  PrintingPolicy PP(Helper.getLangOpts());
5319  CFGBlockTerminatorPrint TPrinter(OS, &Helper, PP);
5320  TPrinter.print(B.getTerminator());
5321  OS << '\n';
5322 
5323  if (ShowColors)
5324  OS.resetColor();
5325  }
5326 
5327  if (print_edges) {
5328  // Print the predecessors of this block.
5329  if (!B.pred_empty()) {
5330  const raw_ostream::Colors Color = raw_ostream::BLUE;
5331  if (ShowColors)
5332  OS.changeColor(Color);
5333  OS << " Preds " ;
5334  if (ShowColors)
5335  OS.resetColor();
5336  OS << '(' << B.pred_size() << "):";
5337  unsigned i = 0;
5338 
5339  if (ShowColors)
5340  OS.changeColor(Color);
5341 
5342  for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end();
5343  I != E; ++I, ++i) {
5344  if (i % 10 == 8)
5345  OS << "\n ";
5346 
5347  CFGBlock *B = *I;
5348  bool Reachable = true;
5349  if (!B) {
5350  Reachable = false;
5351  B = I->getPossiblyUnreachableBlock();
5352  }
5353 
5354  OS << " B" << B->getBlockID();
5355  if (!Reachable)
5356  OS << "(Unreachable)";
5357  }
5358 
5359  if (ShowColors)
5360  OS.resetColor();
5361 
5362  OS << '\n';
5363  }
5364 
5365  // Print the successors of this block.
5366  if (!B.succ_empty()) {
5367  const raw_ostream::Colors Color = raw_ostream::MAGENTA;
5368  if (ShowColors)
5369  OS.changeColor(Color);
5370  OS << " Succs ";
5371  if (ShowColors)
5372  OS.resetColor();
5373  OS << '(' << B.succ_size() << "):";
5374  unsigned i = 0;
5375 
5376  if (ShowColors)
5377  OS.changeColor(Color);
5378 
5379  for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end();
5380  I != E; ++I, ++i) {
5381  if (i % 10 == 8)
5382  OS << "\n ";
5383 
5384  CFGBlock *B = *I;
5385 
5386  bool Reachable = true;
5387  if (!B) {
5388  Reachable = false;
5389  B = I->getPossiblyUnreachableBlock();
5390  }
5391 
5392  if (B) {
5393  OS << " B" << B->getBlockID();
5394  if (!Reachable)
5395  OS << "(Unreachable)";
5396  }
5397  else {
5398  OS << " NULL";
5399  }
5400  }
5401 
5402  if (ShowColors)
5403  OS.resetColor();
5404  OS << '\n';
5405  }
5406  }
5407 }
5408 
5409 /// dump - A simple pretty printer of a CFG that outputs to stderr.
5410 void CFG::dump(const LangOptions &LO, bool ShowColors) const {
5411  print(llvm::errs(), LO, ShowColors);
5412 }
5413 
5414 /// print - A simple pretty printer of a CFG that outputs to an ostream.
5415 void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const {
5416  StmtPrinterHelper Helper(this, LO);
5417 
5418  // Print the entry block.
5419  print_block(OS, this, getEntry(), Helper, true, ShowColors);
5420 
5421  // Iterate through the CFGBlocks and print them one by one.
5422  for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) {
5423  // Skip the entry block, because we already printed it.
5424  if (&(**I) == &getEntry() || &(**I) == &getExit())
5425  continue;
5426 
5427  print_block(OS, this, **I, Helper, true, ShowColors);
5428  }
5429 
5430  // Print the exit block.
5431  print_block(OS, this, getExit(), Helper, true, ShowColors);
5432  OS << '\n';
5433  OS.flush();
5434 }
5435 
5436 /// dump - A simply pretty printer of a CFGBlock that outputs to stderr.
5437 void CFGBlock::dump(const CFG* cfg, const LangOptions &LO,
5438  bool ShowColors) const {
5439  print(llvm::errs(), cfg, LO, ShowColors);
5440 }
5441 
5442 LLVM_DUMP_METHOD void CFGBlock::dump() const {
5443  dump(getParent(), LangOptions(), false);
5444 }
5445 
5446 /// print - A simple pretty printer of a CFGBlock that outputs to an ostream.
5447 /// Generally this will only be called from CFG::print.
5448 void CFGBlock::print(raw_ostream &OS, const CFG* cfg,
5449  const LangOptions &LO, bool ShowColors) const {
5450  StmtPrinterHelper Helper(cfg, LO);
5451  print_block(OS, cfg, *this, Helper, true, ShowColors);
5452  OS << '\n';
5453 }
5454 
5455 /// printTerminator - A simple pretty printer of the terminator of a CFGBlock.
5456 void CFGBlock::printTerminator(raw_ostream &OS,
5457  const LangOptions &LO) const {
5458  CFGBlockTerminatorPrint TPrinter(OS, nullptr, PrintingPolicy(LO));
5459  TPrinter.print(getTerminator());
5460 }
5461 
5463  Stmt *Terminator = this->Terminator;
5464  if (!Terminator)
5465  return nullptr;
5466 
5467  Expr *E = nullptr;
5468 
5469  switch (Terminator->getStmtClass()) {
5470  default:
5471  break;
5472 
5473  case Stmt::CXXForRangeStmtClass:
5474  E = cast<CXXForRangeStmt>(Terminator)->getCond();
5475  break;
5476 
5477  case Stmt::ForStmtClass:
5478  E = cast<ForStmt>(Terminator)->getCond();
5479  break;
5480 
5481  case Stmt::WhileStmtClass:
5482  E = cast<WhileStmt>(Terminator)->getCond();
5483  break;
5484 
5485  case Stmt::DoStmtClass:
5486  E = cast<DoStmt>(Terminator)->getCond();
5487  break;
5488 
5489  case Stmt::IfStmtClass:
5490  E = cast<IfStmt>(Terminator)->getCond();
5491  break;
5492 
5493  case Stmt::ChooseExprClass:
5494  E = cast<ChooseExpr>(Terminator)->getCond();
5495  break;
5496 
5497  case Stmt::IndirectGotoStmtClass:
5498  E = cast<IndirectGotoStmt>(Terminator)->getTarget();
5499  break;
5500 
5501  case Stmt::SwitchStmtClass:
5502  E = cast<SwitchStmt>(Terminator)->getCond();
5503  break;
5504 
5505  case Stmt::BinaryConditionalOperatorClass:
5506  E = cast<BinaryConditionalOperator>(Terminator)->getCond();
5507  break;
5508 
5509  case Stmt::ConditionalOperatorClass:
5510  E = cast<ConditionalOperator>(Terminator)->getCond();
5511  break;
5512 
5513  case Stmt::BinaryOperatorClass: // '&&' and '||'
5514  E = cast<BinaryOperator>(Terminator)->getLHS();
5515  break;
5516 
5517  case Stmt::ObjCForCollectionStmtClass:
5518  return Terminator;
5519  }
5520 
5521  if (!StripParens)
5522  return E;
5523 
5524  return E ? E->IgnoreParens() : nullptr;
5525 }
5526 
5527 //===----------------------------------------------------------------------===//
5528 // CFG Graphviz Visualization
5529 //===----------------------------------------------------------------------===//
5530 
5531 #ifndef NDEBUG
5532 static StmtPrinterHelper* GraphHelper;
5533 #endif
5534 
5535 void CFG::viewCFG(const LangOptions &LO) const {
5536 #ifndef NDEBUG
5537  StmtPrinterHelper H(this, LO);
5538  GraphHelper = &H;
5539  llvm::ViewGraph(this,"CFG");
5540  GraphHelper = nullptr;
5541 #endif
5542 }
5543 
5544 namespace llvm {
5545 
5546 template<>
5547 struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits {
5548  DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
5549 
5550  static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) {
5551 #ifndef NDEBUG
5552  std::string OutSStr;
5553  llvm::raw_string_ostream Out(OutSStr);
5554  print_block(Out,Graph, *Node, *GraphHelper, false, false);
5555  std::string& OutStr = Out.str();
5556 
5557  if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
5558 
5559  // Process string output to make it nicer...
5560  for (unsigned i = 0; i != OutStr.length(); ++i)
5561  if (OutStr[i] == '\n') { // Left justify
5562  OutStr[i] = '\\';
5563  OutStr.insert(OutStr.begin()+i+1, 'l');
5564  }
5565 
5566  return OutStr;
5567 #else
5568  return {};
5569 #endif
5570  }
5571 };
5572 
5573 } // namespace llvm
Expr * getInc()
Definition: Stmt.h:2004
unsigned getNumSemanticExprs() const
Definition: Expr.h:5282
const Expr * getSubExpr() const
Definition: Expr.h:889
bool isBaseInitializer() const
Determine whether this initializer is initializing a base class.
Definition: DeclCXX.h:2319
bool isNoReturn() const
Determines whether this function is known to be &#39;noreturn&#39;, through an attribute on its declaration o...
Definition: Decl.cpp:2932
Defines the clang::ASTContext interface.
const BlockDecl * getBlockDecl() const
Definition: Expr.h:5110
Represents C++ allocator call.
Definition: CFG.h:240
const CXXDestructorDecl * getDestructor() const
Definition: ExprCXX.h:1184
Represents a function declaration or definition.
Definition: Decl.h:1732
Expr * getInit() const
Get the initializer.
Definition: DeclCXX.h:2448
CompoundStmt * getBlock() const
Definition: Stmt.h:2744
bool EvaluateAsRValue(EvalResult &Result, const ASTContext &Ctx) const
EvaluateAsRValue - Return true if this is a constant which we can fold to an rvalue using any crazy t...
A class which contains all the information about a particular captured value.
Definition: Decl.h:3860
pred_iterator pred_end()
Definition: CFG.h:734
PointerType - C99 6.7.5.1 - Pointer Declarators.
Definition: Type.h:2543
QualType getPointeeType() const
Definition: Type.h:2556
A (possibly-)qualified type.
Definition: Type.h:642
bool isBlockPointerType() const
Definition: Type.h:6290
base_class_range bases()
Definition: DeclCXX.h:823
Expr * getCond() const
Definition: Expr.h:3954
static SourceLocation GetEndLoc(Decl *D)
Definition: CFG.cpp:66
AdjacentBlocks::const_iterator const_pred_iterator
Definition: CFG.h:720
iterator beginScopeEndInsert(iterator I, size_t Cnt, BumpVectorContext &C)
Definition: CFG.h:973
const internal::VariadicAllOfMatcher< Stmt > stmt
Matches statements.
const Expr * skipRValueSubobjectAdjustments(SmallVectorImpl< const Expr *> &CommaLHS, SmallVectorImpl< SubobjectAdjustment > &Adjustments) const
Walk outwards from an expression we want to bind a reference to and find the expression whose lifetim...
Definition: Expr.cpp:77
void print(raw_ostream &OS, const PrintingPolicy &Policy, const Twine &PlaceHolder=Twine(), unsigned Indentation=0) const
Definition: Type.h:985
bool operator==(CanQual< T > x, CanQual< U > y)
Expr * getCond()
Definition: Stmt.h:1846
DOTGraphTraits(bool isSimple=false)
Definition: CFG.cpp:5548
ElementList::iterator iterator
Definition: CFG.h:695
succ_iterator succ_begin()
Definition: CFG.h:751
CompoundStmt * getSubStmt()
Definition: Expr.h:3749
DominatorTree GraphTraits specialization so the DominatorTree can be iterable by generic graph iterat...
Definition: Dominators.h:30
bool isReachable() const
Definition: CFG.h:663
const DeclStmt * getConditionVariableDeclStmt() const
If this ForStmt has a condition variable, return the faux DeclStmt associated with the creation of th...
Definition: Stmt.h:1999
Stmt - This represents one statement.
Definition: Stmt.h:66
FunctionType - C99 6.7.5.3 - Function Declarators.
Definition: Type.h:3361
CXXCatchStmt * getHandler(unsigned i)
Definition: StmtCXX.h:104
CFGBlock & getEntry()
Definition: CFG.h:1093
IfStmt - This represents an if/then/else.
Definition: Stmt.h:1421
StorageClass getStorageClass() const
Returns the storage class as written in the source.
Definition: Decl.h:1019
void appendScopeEnd(const VarDecl *VD, const Stmt *S, BumpVectorContext &C)
Definition: CFG.h:908
C Language Family Type Representation.
Expr * getBase() const
Definition: Expr.h:2672
void prependScopeBegin(const VarDecl *VD, const Stmt *S, BumpVectorContext &C)
Definition: CFG.h:903
unsigned getBlockID() const
Definition: CFG.h:856
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:87
Stmt * getHandlerBlock() const
Definition: StmtCXX.h:52
Opcode getOpcode() const
Definition: Expr.h:3254
StringRef P
void appendNewAllocator(CXXNewExpr *NE, BumpVectorContext &C)
Definition: CFG.h:893
QualType getNonReferenceType() const
If Type is a reference type (e.g., const int&), returns the type that the reference refers to ("const...
Definition: Type.h:6231
void appendLifetimeEnds(VarDecl *VD, Stmt *S, BumpVectorContext &C)
Definition: CFG.h:932
The base class of the type hierarchy.
Definition: Type.h:1415
Represents Objective-C&#39;s @throw statement.
Definition: StmtObjC.h:313
Represents C++ object destructor generated from a call to delete.
Definition: CFG.h:409
Represents an array type, per C99 6.7.5.2 - Array Declarators.
Definition: Type.h:2818
iterator begin()
Definition: CFG.h:703
Represents a call to a C++ constructor.
Definition: ExprCXX.h:1250
unsigned IgnoreDefaultsWithCoveredEnums
Definition: CFG.h:779
Represents a C++ constructor within a class.
Definition: DeclCXX.h:2478
Represents a prvalue temporary that is written into memory so that a reference can bind to it...
Definition: ExprCXX.h:4056
float __ovld __cnfn distance(float p0, float p1)
Returns the distance between p0 and p1.
void prependScopeEnd(const VarDecl *VD, const Stmt *S, BumpVectorContext &C)
Definition: CFG.h:912
bool isCompleteDefinition() const
Return true if this decl has its body fully specified.
Definition: Decl.h:3165
unsigned succ_size() const
Definition: CFG.h:769
const CXXDestructorDecl * getDestructorDecl(ASTContext &astContext) const
Definition: CFG.cpp:4667
Stmt * getSubStmt()
Definition: Stmt.h:1289
bool isUnsignedIntegerType() const
Return true if this is an integer type that is unsigned, according to C99 6.2.5p6 [which returns true...
Definition: Type.cpp:1876
bool EvaluateAsInt(llvm::APSInt &Result, const ASTContext &Ctx, SideEffectsKind AllowSideEffects=SE_NoSideEffects) const
EvaluateAsInt - Return true if this is a constant which we can fold and convert to an integer...
Represents a variable declaration or definition.
Definition: Decl.h:812
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6716
CFGBlock * getReachableBlock() const
Get the reachable block, if one exists.
Definition: CFG.h:640
const char * getName() const
Definition: Stmt.cpp:343
Stmt * getThen()
Definition: Stmt.h:1508
Describes how types, statements, expressions, and declarations should be printed. ...
Definition: PrettyPrinter.h:38
Defines the Objective-C statement AST node classes.
static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper, const CFGElement &E)
Definition: CFG.cpp:5107
A C++ throw-expression (C++ [except.throw]).
Definition: ExprCXX.h:1003
Represents an expression – generally a full-expression – that introduces cleanups to be run at the ...
Definition: ExprCXX.h:3021
static bool isAssignmentOp(Opcode Opc)
Definition: Expr.h:3342
Defines the clang::Expr interface and subclasses for C++ expressions.
const Stmt * getSubStmt() const
Definition: StmtObjC.h:356
const char * getStmtClassName() const
Definition: Stmt.cpp:75
Represents a function call that returns a C++ object by value.
Definition: CFG.h:179
LabelStmt - Represents a label, which has a substatement.
Definition: Stmt.h:1327
const AstTypeMatcher< RecordType > recordType
Matches record types (e.g.
static TryResult bothKnownTrue(TryResult R1, TryResult R2)
Definition: CFG.cpp:382
bool pred_empty() const
Definition: CFG.h:773
Stmt * getBody()
Definition: Stmt.h:1944
CFGBlock * getPossiblyUnreachableBlock() const
Get the potentially unreachable block.
Definition: CFG.h:645
void print(raw_ostream &Out, unsigned Indentation=0, bool PrintInstantiation=false) const
QualType getPointeeType() const
Definition: Type.h:2660
DeclStmt * getConditionVariableDeclStmt()
If this SwitchStmt has a condition variable, return the faux DeclStmt associated with the creation of...
Definition: Stmt.h:1737
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:154
void setLoopTarget(const Stmt *loopTarget)
Definition: CFG.h:837
static std::string getNodeLabel(const CFGBlock *Node, const CFG *Graph)
Definition: CFG.cpp:5550
field_range fields() const
Definition: Decl.h:3780
Represents a member of a struct/union/class.
Definition: Decl.h:2575
TypeSourceInfo * getTypeSourceInfo() const
Returns the declarator information for a base class or delegating initializer.
Definition: DeclCXX.h:2380
iterator insertAutomaticObjDtor(iterator I, VarDecl *VD, Stmt *S)
Definition: CFG.h:952
Defines the ExceptionSpecificationType enumeration and various utility functions. ...
void printTerminator(raw_ostream &OS, const LangOptions &LO) const
printTerminator - A simple pretty printer of the terminator of a CFGBlock.
Definition: CFG.cpp:5456
Represents C++ object destructor implicitly generated for automatic object or temporary bound to cons...
Definition: CFG.h:384
void appendAutomaticObjDtor(VarDecl *VD, Stmt *S, BumpVectorContext &C)
Definition: CFG.h:928
bool isReferenceType() const
Definition: Type.h:6294
const CXXConstructExpr * getConstructExpr() const
Returns the CXXConstructExpr from this new-expression, or null.
Definition: ExprCXX.h:2014
clang::CharUnits operator*(clang::CharUnits::QuantityType Scale, const clang::CharUnits &CU)
Definition: CharUnits.h:208
bool isAllEnumCasesCovered() const
Returns true if the SwitchStmt is a switch of an enum value and all cases have been explicitly covere...
Definition: Stmt.h:1774
Expr * getSubExpr()
Definition: Expr.h:2968
void setTerminator(CFGTerminator Term)
Definition: CFG.h:835
Keeps track of the various options that can be enabled, which controls the dialect of C or C++ that i...
Definition: LangOptions.h:50
iterator end()
Definition: CFG.h:1079
Represents Objective-C&#39;s @catch statement.
Definition: StmtObjC.h:74
AdjacentBlocks::const_iterator const_succ_iterator
Definition: CFG.h:727
bool isGLValue() const
Definition: Expr.h:252
IndirectGotoStmt - This represents an indirect goto.
Definition: Stmt.h:2073
Describes an C or C++ initializer list.
Definition: Expr.h:4117
bool EvaluateAsBooleanCondition(bool &Result, const ASTContext &Ctx) const
EvaluateAsBooleanCondition - Return true if this is a constant which we can fold and convert to a boo...
BinaryOperatorKind
Expr * getArraySize()
Definition: ExprCXX.h:1968
ForStmt - This represents a &#39;for (init;cond;inc)&#39; stmt.
Definition: Stmt.h:1971
APValue Val
Val - This is the value the expression can be folded to.
Definition: Expr.h:573
LabelDecl * getDecl() const
Definition: Stmt.h:1344
Forward-declares and imports various common LLVM datatypes that clang wants to use unqualified...
capture_init_iterator capture_init_begin()
Retrieve the first initialization argument for this lambda expression (which initializes the first ca...
Definition: ExprCXX.h:1744
Expr * getInitializer()
The initializer of this new-expression.
Definition: ExprCXX.h:2006
Stmt * getBody()
Definition: Stmt.h:2005
CFGCallback * Observer
Definition: CFG.h:1016
child_range children()
Definition: Stmt.cpp:229
static QualType getReferenceInitTemporaryType(const Expr *Init, bool *FoundMTE=nullptr)
Retrieve the type of the temporary object whose lifetime was extended by a local reference with the g...
Definition: CFG.cpp:1555
A builtin binary operation expression such as "x + y" or "x <= y".
Definition: Expr.h:3219
Stmt * getInit()
Definition: Stmt.h:1984
CXXForRangeStmt - This represents C++0x [stmt.ranged]&#39;s ranged for statement, represented as &#39;for (ra...
Definition: StmtCXX.h:127
static bool areExprTypesCompatible(const Expr *E1, const Expr *E2)
For an expression x == Foo && x == Bar, this determines whether the Foo and Bar are either of the sam...
Definition: CFG.cpp:121
void print(raw_ostream &OS, const CFG *cfg, const LangOptions &LO, bool ShowColors) const
print - A simple pretty printer of a CFGBlock that outputs to an ostream.
Definition: CFG.cpp:5448
Scope - A scope is a transient data structure that is used while parsing the program.
Definition: Scope.h:40
const Type * getTypePtr() const
Retrieves a pointer to the underlying (unqualified) type.
Definition: Type.h:6058
CaseStmt - Represent a case statement.
Definition: Stmt.h:1128
void appendLoopExit(const Stmt *LoopStmt, BumpVectorContext &C)
Definition: CFG.h:936
Expr * getCond()
Definition: Stmt.h:2003
bool isInt() const
Definition: APValue.h:234
CastExpr - Base class for type casts, including both implicit casts (ImplicitCastExpr) and explicit c...
Definition: Expr.h:2903
Represents binding an expression to a temporary.
Definition: ExprCXX.h:1205
CXXTemporary * getTemporary()
Definition: ExprCXX.h:1224
FieldDecl * getAnyMember() const
Definition: DeclCXX.h:2392
A C++ lambda expression, which produces a function object (of unspecified type) that can be invoked l...
Definition: ExprCXX.h:1599
bool hasTrivialDestructor() const
Determine whether this class has a trivial destructor (C++ [class.dtor]p3)
Definition: DeclCXX.h:1478
bool isTypeDependent() const
isTypeDependent - Determines whether this expression is type-dependent (C++ [temp.dep.expr]), which means that its type could change from one template instantiation to the next.
Definition: Expr.h:167
child_range children()
Definition: Stmt.h:1075
CXXDestructorDecl * getDestructor() const
Returns the destructor decl for this class.
Definition: DeclCXX.cpp:1697
VarDecl * getConditionVariable() const
Retrieve the variable declared in this "for" statement, if any.
Definition: Stmt.cpp:897
bool getNoReturn() const
Definition: Type.h:3518
Stmt * getBody()
Definition: Stmt.h:1692
Stmt * getInit()
Definition: Stmt.h:1564
arg_iterator placement_arg_end()
Definition: ExprCXX.h:2045
Iterator for iterating over Stmt * arrays that contain only Expr *.
Definition: Stmt.h:717
llvm::DenseMap< const Stmt *, const CFGBlock * > ForcedBlkExprs
Definition: CFG.h:1013
CFGBlockListTy::const_iterator const_iterator
Definition: CFG.h:1071
CFG * getParent() const
Definition: CFG.h:858
void appendConstructor(CXXConstructExpr *CE, const ConstructionContext *CC, BumpVectorContext &C)
Definition: CFG.h:877
CompoundStmt - This represents a group of statements like { stmt stmt }.
Definition: Stmt.h:975
CXXRecordDecl * getAsCXXRecordDecl() const
Retrieves the CXXRecordDecl that this type refers to, either because the type is a RecordType or beca...
Definition: Type.cpp:1605
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3686
bool isDelegatingInitializer() const
Determine whether this initializer is creating a delegating constructor.
Definition: DeclCXX.h:2347
UnaryExprOrTypeTraitExpr - expression with either a type or (unevaluated) expression operand...
Definition: Expr.h:2227
void appendBaseDtor(const CXXBaseSpecifier *BS, BumpVectorContext &C)
Definition: CFG.h:916
static bool shouldAddCase(bool &switchExclusivelyCovered, const Expr::EvalResult *switchCond, const CaseStmt *CS, ASTContext &Ctx)
Definition: CFG.cpp:3919
Represents a single basic block in a source-level CFG.
Definition: CFG.h:552
ConstantExpr - An expression that occurs in a constant context.
Definition: Expr.h:903
llvm::APSInt EvaluateKnownConstInt(const ASTContext &Ctx, SmallVectorImpl< PartialDiagnosticAt > *Diag=nullptr) const
EvaluateKnownConstInt - Call EvaluateAsRValue and return the folded integer.
bool isNoReturn(ASTContext &astContext) const
Definition: CFG.cpp:4724
This represents one expression.
Definition: Expr.h:106
Defines the clang::LangOptions interface.
Stmt * getTerminatorCondition(bool StripParens=true)
Definition: CFG.cpp:5462
static std::tuple< const DeclRefExpr *, BinaryOperatorKind, const Expr * > tryNormalizeBinaryOperator(const BinaryOperator *B)
Tries to interpret a binary operator into Decl Op Expr form, if Expr is an integer literal or an enum...
Definition: CFG.cpp:90
DeclStmt * getEndStmt()
Definition: StmtCXX.h:158
SourceLocation End
std::string Label
Represents a source-level, intra-procedural CFG that represents the control-flow of a Stmt...
Definition: CFG.h:1003
Represents a C++ functional cast expression that builds a temporary object.
Definition: ExprCXX.h:1549
BlockExpr - Adaptor class for mixing a BlockDecl with expressions.
Definition: Expr.h:5096
Represents a C++ destructor within a class.
Definition: DeclCXX.h:2700
bool succ_empty() const
Definition: CFG.h:770
VarDecl * getExceptionDecl() const
Definition: StmtCXX.h:50
unsigned getNumInits() const
Definition: Expr.h:4147
const Expr * getCallee() const
Definition: Expr.h:2445
Represents C++ constructor call.
Definition: CFG.h:151
QualType getArgumentType() const
Definition: Expr.h:2264
#define bool
Definition: stdbool.h:31
Stmt * getBody()
Definition: Stmt.h:1858
const CompoundStmt * getSynchBody() const
Definition: StmtObjC.h:282
ElementList::const_iterator const_iterator
Definition: CFG.h:696
Expr * getRHS()
Definition: Stmt.h:1229
bool isTemporaryDtorsBranch() const
Definition: CFG.h:513
Represents Objective-C&#39;s @synchronized statement.
Definition: StmtObjC.h:262
SourceLocation Begin
DOTGraphTraits(bool isSimple=false)
CXXTryStmt - A C++ try block, including all handlers.
Definition: StmtCXX.h:65
const AstTypeMatcher< ArrayType > arrayType
Matches all kinds of arrays.
std::reverse_iterator< body_iterator > reverse_body_iterator
Definition: Stmt.h:1043
QualType getType() const
Definition: Expr.h:128
static void print_initializer(raw_ostream &OS, StmtPrinterHelper &Helper, const CXXCtorInitializer *I)
Definition: CFG.cpp:5007
LabelDecl * getLabel() const
Definition: Stmt.h:2051
StorageDuration getStorageDuration() const
Retrieve the storage duration for the materialized temporary.
Definition: ExprCXX.h:4100
An expression that sends a message to the given Objective-C object or class.
Definition: ExprObjC.h:904
SwitchCase * getSwitchCaseList()
Definition: Stmt.h:1749
UnaryOperator - This represents the unary-expression&#39;s (except sizeof and alignof), the postinc/postdec operators from postfix-expression, and various extensions.
Definition: Expr.h:1901
static bool CanThrow(Expr *E, ASTContext &Ctx)
Definition: CFG.cpp:2402
const Type * getBaseElementTypeUnsafe() const
Get the base element type of this type, potentially discarding type qualifiers.
Definition: Type.h:6674
Expr * getCond()
Definition: Stmt.h:1496
ValueDecl * getDecl()
Definition: Expr.h:1119
Represents C++ object destructor implicitly generated for base object in destructor.
Definition: CFG.h:435
The result type of a method or function.
QualType getDestroyedType() const
Retrieve the type being destroyed.
Definition: ExprCXX.cpp:178
const Expr * getSubExpr() const
Definition: ExprCXX.h:1228
bool isNull() const
Return true if this QualType doesn&#39;t point to a type yet.
Definition: Type.h:707
DoStmt - This represents a &#39;do/while&#39; stmt.
Definition: Stmt.h:1919
static const ConstructionContext * createFromLayers(BumpVectorContext &C, const ConstructionContextLayer *TopLayer)
Consume the construction context layer, together with its parent layers, and wrap it up into a comple...
std::reverse_iterator< decl_iterator > reverse_decl_iterator
Definition: Stmt.h:931
RecordDecl * getDecl() const
Definition: Type.h:4366
Expr * getArgument()
Definition: ExprCXX.h:2142
void appendStmt(Stmt *statement, BumpVectorContext &C)
Definition: CFG.h:873
CFGTerminator getTerminator()
Definition: CFG.h:840
OpaqueValueExpr - An expression referring to an opaque object of a fixed type and value class...
Definition: Expr.h:939
Kind
PseudoObjectExpr - An expression which accesses a pseudo-object l-value.
Definition: Expr.h:5218
Construction context can be seen as a linked list of multiple layers.
Encodes a location in the source.
Stmt * getLabel()
Definition: CFG.h:851
unsigned getNumHandlers() const
Definition: StmtCXX.h:103
Expr * getSubExpr() const
Definition: Expr.h:1931
Represents a C++ temporary.
Definition: ExprCXX.h:1173
Represents a new-expression for memory allocation and constructor calls, e.g: "new CXXNewExpr(foo)"...
Definition: ExprCXX.h:1861
Expr * getLHS()
Definition: Stmt.h:1217
void setLabel(Stmt *Statement)
Definition: CFG.h:836
static std::unique_ptr< CFG > buildCFG(const Decl *D, Stmt *AST, ASTContext *C, const BuildOptions &BO)
Builds a CFG from an AST.
Definition: CFG.cpp:4660
ASTContext & getASTContext() const LLVM_READONLY
Definition: DeclBase.cpp:376
iterator insertScopeEnd(iterator I, VarDecl *VD, Stmt *S)
Definition: CFG.h:977
Stmt * getElse()
Definition: Stmt.h:1517
DeclStmt - Adaptor class for mixing declarations with statements and expressions. ...
Definition: Stmt.h:877
bool PruneTriviallyFalseEdges
Definition: CFG.h:1017
reverse_body_iterator body_rend()
Definition: Stmt.h:1049
QualType getBaseElementType(const ArrayType *VAT) const
Return the innermost element type of an array type.
const ConstantArrayType * getAsConstantArrayType(QualType T) const
Definition: ASTContext.h:2412
Expr * getCond()
Definition: Stmt.h:1680
virtual void compareAlwaysTrue(const BinaryOperator *B, bool isAlwaysTrue)
Definition: CFG.h:991
StmtVisitor - This class implements a simple visitor for Stmt subclasses.
Definition: StmtVisitor.h:186
static void print_block(raw_ostream &OS, const CFG *cfg, const CFGBlock &B, StmtPrinterHelper &Helper, bool print_edges, bool ShowColors)
Definition: CFG.cpp:5229
const ArrayType * getAsArrayType(QualType T) const
Type Query functions.
bool isArray() const
Definition: ExprCXX.h:1966
decl_iterator decl_begin()
Definition: Stmt.h:926
bool isValueDependent() const
isValueDependent - Determines whether this expression is value-dependent (C++ [temp.dep.constexpr]).
Definition: Expr.h:149
bool isKnownToHaveBooleanValue() const
isKnownToHaveBooleanValue - Return true if this is an integer expression that is known to return 0 or...
Definition: Expr.cpp:135
reverse_decl_iterator decl_rbegin()
Definition: Stmt.h:933
ImplicitCastExpr - Allows us to explicitly represent implicit type conversions, which have no direct ...
Definition: Expr.h:3037
static bool isCXXRecordTypedCall(Expr *E)
Returns true when call expression CE needs to be represented by CFGCXXRecordTypedCall, as opposed to a regular CFGStmt.
Definition: CFG.h:183
static QualType findBoundMemberType(const Expr *expr)
Given an expression of bound-member type, find the type of the member.
Definition: Expr.cpp:2524
Expr ** getInits()
Retrieve the set of initializers.
Definition: Expr.h:4150
void appendScopeBegin(const VarDecl *VD, const Stmt *S, BumpVectorContext &C)
Definition: CFG.h:898
iterator begin()
Definition: CFG.h:1078
static bool isLogicalOp(Opcode Opc)
Definition: Expr.h:3339
static const Expr * tryTransformToIntOrEnumConstant(const Expr *E)
Helper for tryNormalizeBinaryOperator.
Definition: CFG.cpp:75
VarDecl * getConditionVariable()
Retrieve the variable declared in this "switch" statement, if any.
Definition: Stmt.cpp:960
DeclStmt * getConditionVariableDeclStmt()
If this WhileStmt has a condition variable, return the faux DeclStmt associated with the creation of ...
Definition: Stmt.h:1886
void dump() const
Definition: CFG.cpp:5442
succ_iterator succ_end()
Definition: CFG.h:752
StmtExpr - This is the GNU Statement Expression extension: ({int X=4; X;}).
Definition: Expr.h:3733
bool isArgumentType() const
Definition: Expr.h:2263
Represents end of a scope implicitly generated by the compiler after the last Stmt in a CompoundStmt&#39;...
Definition: CFG.h:336
Optional< T > getAs() const
Convert to the specified CFGElement type, returning None if this CFGElement is not of the desired typ...
Definition: CFG.h:110
Expr * getLHS() const
Definition: Expr.h:3259
Defines various enumerations that describe declaration and type specifiers.
AddrLabelExpr - The GNU address of label extension, representing &&label.
Definition: Expr.h:3689
ast_type_traits::DynTypedNode Node
pred_iterator pred_begin()
Definition: CFG.h:733
OpaqueValueExpr * getOpaqueValue() const
getOpaqueValue - Return the opaque value placeholder.
Definition: Expr.h:3630
Dataflow Directional Tag Classes.
child_range children()
VarDecl * getConditionVariable()
Retrieve the variable declared in this "while" statement, if any.
Definition: Stmt.cpp:1016
DeclContext - This is used only as base class of specific decl types that can act as declaration cont...
Definition: DeclBase.h:1261
EvalResult is a struct with detailed info about an evaluated expression.
Definition: Expr.h:571
Represents a delete expression for memory deallocation and destructor calls, e.g. ...
Definition: ExprCXX.h:2088
ArrayRef< Capture > captures() const
Definition: Decl.h:3981
iterator beginAutomaticObjDtorsInsert(iterator I, size_t Cnt, BumpVectorContext &C)
Definition: CFG.h:947
virtual void compareBitwiseEquality(const BinaryOperator *B, bool isAlwaysTrue)
Definition: CFG.h:992
FunctionDecl * getDirectCallee()
If the callee is a FunctionDecl, return it. Otherwise return 0.
Definition: Expr.cpp:1279
const Stmt * stripLabelLikeStatements() const
Strip off all label-like statements.
Definition: Stmt.cpp:161
static const VariableArrayType * FindVA(const Type *t)
Definition: CFG.cpp:1255
void appendCXXRecordTypedCall(Expr *E, const ConstructionContext *CC, BumpVectorContext &C)
Definition: CFG.h:882
const Expr * getInit() const
Definition: Decl.h:1219
unsigned pred_size() const
Definition: CFG.h:772
StmtClass getStmtClass() const
Definition: Stmt.h:763
static StmtPrinterHelper * GraphHelper
Definition: CFG.cpp:5532
void appendDeleteDtor(CXXRecordDecl *RD, CXXDeleteExpr *DE, BumpVectorContext &C)
Definition: CFG.h:940
const CXXRecordDecl * getParent() const
Returns the parent of this method declaration, which is the class in which this method is defined...
Definition: DeclCXX.h:2166
bool isAnyDestructorNoReturn() const
Returns true if the class destructor, or any implicitly invoked destructors are marked noreturn...
Definition: DeclCXX.cpp:1710
const Type * getBaseClass() const
If this is a base class initializer, returns the type of the base class.
Definition: DeclCXX.cpp:2256
SEHExceptStmt * getExceptHandler() const
Returns 0 if not defined.
Definition: Stmt.cpp:1108
const Decl * getSingleDecl() const
Definition: Stmt.h:892
FunctionType::ExtInfo getFunctionExtInfo(const Type &t)
Definition: Type.h:6183
const Expr * getSynchExpr() const
Definition: StmtObjC.h:290
void appendMemberDtor(FieldDecl *FD, BumpVectorContext &C)
Definition: CFG.h:920
void appendInitializer(CXXCtorInitializer *initializer, BumpVectorContext &C)
Definition: CFG.h:888
This class represents a potential adjacent block in the CFG.
Definition: CFG.h:621
bool isSingleDecl() const
isSingleDecl - This method returns true if this DeclStmt refers to a single Decl. ...
Definition: Stmt.h:890
Represents the point where the lifetime of an automatic object ends.
Definition: CFG.h:285
DeclStmt * getConditionVariableDeclStmt()
If this IfStmt has a condition variable, return the faux DeclStmt associated with the creation of tha...
Definition: Stmt.h:1552
Stmt * getStmt()
Definition: CFG.h:510
Represents a single point (AST node) in the program that requires attention during construction of an...
Expr * IgnoreParenImpCasts() LLVM_READONLY
IgnoreParenImpCasts - Ignore parentheses and implicit casts.
Definition: Expr.cpp:2677
llvm::APInt getValue() const
Definition: Expr.h:1297
Represents a __leave statement.
Definition: Stmt.h:2804
LabelDecl * getLabel() const
Definition: Expr.h:3711
SwitchStmt - This represents a &#39;switch&#39; stmt.
Definition: Stmt.h:1620
Pointer to a block type.
Definition: Type.h:2645
CFGBlock * getIndirectGotoBlock()
Definition: CFG.h:1098
A helper class that allows the use of isa/cast/dyncast to detect TagType objects of structs/unions/cl...
Definition: Type.h:4356
bool body_empty() const
Definition: Stmt.h:1002
Represents Objective-C&#39;s collection statement.
Definition: StmtObjC.h:24
AbstractConditionalOperator - An abstract base class for ConditionalOperator and BinaryConditionalOpe...
Definition: Expr.h:3472
Represents a C++ base or member initializer.
Definition: DeclCXX.h:2253
reverse_decl_iterator decl_rend()
Definition: Stmt.h:937
const ConstructionContextItem & getItem() const
Stmt * getInit()
Definition: Stmt.h:1701
iterator insertLifetimeEnds(iterator I, VarDecl *VD, Stmt *S)
Definition: CFG.h:965
void print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const
print - A simple pretty printer of a CFG that outputs to an ostream.
Definition: CFG.cpp:5415
CanQualType BoundMemberTy
Definition: ASTContext.h:1044
decl_range decls()
Definition: Stmt.h:920
static void print_construction_context(raw_ostream &OS, StmtPrinterHelper &Helper, const ConstructionContext *CC)
Definition: CFG.cpp:5028
static const ConstructionContextLayer * create(BumpVectorContext &C, const ConstructionContextItem &Item, const ConstructionContextLayer *Parent=nullptr)
Represents a base class of a C++ class.
Definition: DeclCXX.h:192
arg_iterator placement_arg_begin()
Definition: ExprCXX.h:2042
DeclStmt * getRangeStmt()
Definition: StmtCXX.h:154
Expr * getRHS() const
Definition: Expr.h:3958
SEHFinallyStmt * getFinallyHandler() const
Definition: Stmt.cpp:1112
GotoStmt - This represents a direct goto.
Definition: Stmt.h:2038
A use of a default initializer in a constructor or in aggregate initialization.
Definition: ExprCXX.h:1125
Expr * getTarget()
Definition: Stmt.h:2093
unsigned IgnoreNullPredecessors
Definition: CFG.h:778
bool hasNoReturnElement() const
Definition: