clang  9.0.0svn
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  Expr::EvalResult L1Result, L2Result;
1043  if (!Expr1->EvaluateAsInt(L1Result, *Context) ||
1044  !Expr2->EvaluateAsInt(L2Result, *Context))
1045  return {};
1046 
1047  llvm::APSInt L1 = L1Result.Val.getInt();
1048  llvm::APSInt L2 = L2Result.Val.getInt();
1049 
1050  // Can't compare signed with unsigned or with different bit width.
1051  if (L1.isSigned() != L2.isSigned() || L1.getBitWidth() != L2.getBitWidth())
1052  return {};
1053 
1054  // Values that will be used to determine if result of logical
1055  // operator is always true/false
1056  const llvm::APSInt Values[] = {
1057  // Value less than both Value1 and Value2
1058  llvm::APSInt::getMinValue(L1.getBitWidth(), L1.isUnsigned()),
1059  // L1
1060  L1,
1061  // Value between Value1 and Value2
1062  ((L1 < L2) ? L1 : L2) + llvm::APSInt(llvm::APInt(L1.getBitWidth(), 1),
1063  L1.isUnsigned()),
1064  // L2
1065  L2,
1066  // Value greater than both Value1 and Value2
1067  llvm::APSInt::getMaxValue(L1.getBitWidth(), L1.isUnsigned()),
1068  };
1069 
1070  // Check whether expression is always true/false by evaluating the following
1071  // * variable x is less than the smallest literal.
1072  // * variable x is equal to the smallest literal.
1073  // * Variable x is between smallest and largest literal.
1074  // * Variable x is equal to the largest literal.
1075  // * Variable x is greater than largest literal.
1076  bool AlwaysTrue = true, AlwaysFalse = true;
1077  for (const llvm::APSInt &Value : Values) {
1078  TryResult Res1, Res2;
1079  Res1 = analyzeLogicOperatorCondition(BO1, Value, L1);
1080  Res2 = analyzeLogicOperatorCondition(BO2, Value, L2);
1081 
1082  if (!Res1.isKnown() || !Res2.isKnown())
1083  return {};
1084 
1085  if (B->getOpcode() == BO_LAnd) {
1086  AlwaysTrue &= (Res1.isTrue() && Res2.isTrue());
1087  AlwaysFalse &= !(Res1.isTrue() && Res2.isTrue());
1088  } else {
1089  AlwaysTrue &= (Res1.isTrue() || Res2.isTrue());
1090  AlwaysFalse &= !(Res1.isTrue() || Res2.isTrue());
1091  }
1092  }
1093 
1094  if (AlwaysTrue || AlwaysFalse) {
1095  if (BuildOpts.Observer)
1096  BuildOpts.Observer->compareAlwaysTrue(B, AlwaysTrue);
1097  return TryResult(AlwaysTrue);
1098  }
1099  return {};
1100  }
1101 
1102  /// Try and evaluate an expression to an integer constant.
1103  bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) {
1104  if (!BuildOpts.PruneTriviallyFalseEdges)
1105  return false;
1106  return !S->isTypeDependent() &&
1107  !S->isValueDependent() &&
1108  S->EvaluateAsRValue(outResult, *Context);
1109  }
1110 
1111  /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1
1112  /// if we can evaluate to a known value, otherwise return -1.
1113  TryResult tryEvaluateBool(Expr *S) {
1114  if (!BuildOpts.PruneTriviallyFalseEdges ||
1115  S->isTypeDependent() || S->isValueDependent())
1116  return {};
1117 
1118  if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(S)) {
1119  if (Bop->isLogicalOp()) {
1120  // Check the cache first.
1121  CachedBoolEvalsTy::iterator I = CachedBoolEvals.find(S);
1122  if (I != CachedBoolEvals.end())
1123  return I->second; // already in map;
1124 
1125  // Retrieve result at first, or the map might be updated.
1126  TryResult Result = evaluateAsBooleanConditionNoCache(S);
1127  CachedBoolEvals[S] = Result; // update or insert
1128  return Result;
1129  }
1130  else {
1131  switch (Bop->getOpcode()) {
1132  default: break;
1133  // For 'x & 0' and 'x * 0', we can determine that
1134  // the value is always false.
1135  case BO_Mul:
1136  case BO_And: {
1137  // If either operand is zero, we know the value
1138  // must be false.
1139  Expr::EvalResult LHSResult;
1140  if (Bop->getLHS()->EvaluateAsInt(LHSResult, *Context)) {
1141  llvm::APSInt IntVal = LHSResult.Val.getInt();
1142  if (!IntVal.getBoolValue()) {
1143  return TryResult(false);
1144  }
1145  }
1146  Expr::EvalResult RHSResult;
1147  if (Bop->getRHS()->EvaluateAsInt(RHSResult, *Context)) {
1148  llvm::APSInt IntVal = RHSResult.Val.getInt();
1149  if (!IntVal.getBoolValue()) {
1150  return TryResult(false);
1151  }
1152  }
1153  }
1154  break;
1155  }
1156  }
1157  }
1158 
1159  return evaluateAsBooleanConditionNoCache(S);
1160  }
1161 
1162  /// Evaluate as boolean \param E without using the cache.
1163  TryResult evaluateAsBooleanConditionNoCache(Expr *E) {
1164  if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(E)) {
1165  if (Bop->isLogicalOp()) {
1166  TryResult LHS = tryEvaluateBool(Bop->getLHS());
1167  if (LHS.isKnown()) {
1168  // We were able to evaluate the LHS, see if we can get away with not
1169  // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
1170  if (LHS.isTrue() == (Bop->getOpcode() == BO_LOr))
1171  return LHS.isTrue();
1172 
1173  TryResult RHS = tryEvaluateBool(Bop->getRHS());
1174  if (RHS.isKnown()) {
1175  if (Bop->getOpcode() == BO_LOr)
1176  return LHS.isTrue() || RHS.isTrue();
1177  else
1178  return LHS.isTrue() && RHS.isTrue();
1179  }
1180  } else {
1181  TryResult RHS = tryEvaluateBool(Bop->getRHS());
1182  if (RHS.isKnown()) {
1183  // We can't evaluate the LHS; however, sometimes the result
1184  // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
1185  if (RHS.isTrue() == (Bop->getOpcode() == BO_LOr))
1186  return RHS.isTrue();
1187  } else {
1188  TryResult BopRes = checkIncorrectLogicOperator(Bop);
1189  if (BopRes.isKnown())
1190  return BopRes.isTrue();
1191  }
1192  }
1193 
1194  return {};
1195  } else if (Bop->isEqualityOp()) {
1196  TryResult BopRes = checkIncorrectEqualityOperator(Bop);
1197  if (BopRes.isKnown())
1198  return BopRes.isTrue();
1199  } else if (Bop->isRelationalOp()) {
1200  TryResult BopRes = checkIncorrectRelationalOperator(Bop);
1201  if (BopRes.isKnown())
1202  return BopRes.isTrue();
1203  }
1204  }
1205 
1206  bool Result;
1207  if (E->EvaluateAsBooleanCondition(Result, *Context))
1208  return Result;
1209 
1210  return {};
1211  }
1212 
1213  bool hasTrivialDestructor(VarDecl *VD);
1214 };
1215 
1216 } // namespace
1217 
1218 inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder,
1219  const Stmt *stmt) const {
1220  return builder.alwaysAdd(stmt) || kind == AlwaysAdd;
1221 }
1222 
1223 bool CFGBuilder::alwaysAdd(const Stmt *stmt) {
1224  bool shouldAdd = BuildOpts.alwaysAdd(stmt);
1225 
1226  if (!BuildOpts.forcedBlkExprs)
1227  return shouldAdd;
1228 
1229  if (lastLookup == stmt) {
1230  if (cachedEntry) {
1231  assert(cachedEntry->first == stmt);
1232  return true;
1233  }
1234  return shouldAdd;
1235  }
1236 
1237  lastLookup = stmt;
1238 
1239  // Perform the lookup!
1240  CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs;
1241 
1242  if (!fb) {
1243  // No need to update 'cachedEntry', since it will always be null.
1244  assert(!cachedEntry);
1245  return shouldAdd;
1246  }
1247 
1248  CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt);
1249  if (itr == fb->end()) {
1250  cachedEntry = nullptr;
1251  return shouldAdd;
1252  }
1253 
1254  cachedEntry = &*itr;
1255  return true;
1256 }
1257 
1258 // FIXME: Add support for dependent-sized array types in C++?
1259 // Does it even make sense to build a CFG for an uninstantiated template?
1260 static const VariableArrayType *FindVA(const Type *t) {
1261  while (const ArrayType *vt = dyn_cast<ArrayType>(t)) {
1262  if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt))
1263  if (vat->getSizeExpr())
1264  return vat;
1265 
1266  t = vt->getElementType().getTypePtr();
1267  }
1268 
1269  return nullptr;
1270 }
1271 
1272 void CFGBuilder::consumeConstructionContext(
1273  const ConstructionContextLayer *Layer, Expr *E) {
1274  assert((isa<CXXConstructExpr>(E) || isa<CallExpr>(E) ||
1275  isa<ObjCMessageExpr>(E)) && "Expression cannot construct an object!");
1276  if (const ConstructionContextLayer *PreviouslyStoredLayer =
1277  ConstructionContextMap.lookup(E)) {
1278  (void)PreviouslyStoredLayer;
1279  // We might have visited this child when we were finding construction
1280  // contexts within its parents.
1281  assert(PreviouslyStoredLayer->isStrictlyMoreSpecificThan(Layer) &&
1282  "Already within a different construction context!");
1283  } else {
1284  ConstructionContextMap[E] = Layer;
1285  }
1286 }
1287 
1288 void CFGBuilder::findConstructionContexts(
1289  const ConstructionContextLayer *Layer, Stmt *Child) {
1290  if (!BuildOpts.AddRichCXXConstructors)
1291  return;
1292 
1293  if (!Child)
1294  return;
1295 
1296  auto withExtraLayer = [this, Layer](const ConstructionContextItem &Item) {
1297  return ConstructionContextLayer::create(cfg->getBumpVectorContext(), Item,
1298  Layer);
1299  };
1300 
1301  switch(Child->getStmtClass()) {
1302  case Stmt::CXXConstructExprClass:
1303  case Stmt::CXXTemporaryObjectExprClass: {
1304  // Support pre-C++17 copy elision AST.
1305  auto *CE = cast<CXXConstructExpr>(Child);
1306  if (BuildOpts.MarkElidedCXXConstructors && CE->isElidable()) {
1307  findConstructionContexts(withExtraLayer(CE), CE->getArg(0));
1308  }
1309 
1310  consumeConstructionContext(Layer, CE);
1311  break;
1312  }
1313  // FIXME: This, like the main visit, doesn't support CUDAKernelCallExpr.
1314  // FIXME: An isa<> would look much better but this whole switch is a
1315  // workaround for an internal compiler error in MSVC 2015 (see r326021).
1316  case Stmt::CallExprClass:
1317  case Stmt::CXXMemberCallExprClass:
1318  case Stmt::CXXOperatorCallExprClass:
1319  case Stmt::UserDefinedLiteralClass:
1320  case Stmt::ObjCMessageExprClass: {
1321  auto *E = cast<Expr>(Child);
1323  consumeConstructionContext(Layer, E);
1324  break;
1325  }
1326  case Stmt::ExprWithCleanupsClass: {
1327  auto *Cleanups = cast<ExprWithCleanups>(Child);
1328  findConstructionContexts(Layer, Cleanups->getSubExpr());
1329  break;
1330  }
1331  case Stmt::CXXFunctionalCastExprClass: {
1332  auto *Cast = cast<CXXFunctionalCastExpr>(Child);
1333  findConstructionContexts(Layer, Cast->getSubExpr());
1334  break;
1335  }
1336  case Stmt::ImplicitCastExprClass: {
1337  auto *Cast = cast<ImplicitCastExpr>(Child);
1338  // Should we support other implicit cast kinds?
1339  switch (Cast->getCastKind()) {
1340  case CK_NoOp:
1341  case CK_ConstructorConversion:
1342  findConstructionContexts(Layer, Cast->getSubExpr());
1343  break;
1344  default:
1345  break;
1346  }
1347  break;
1348  }
1349  case Stmt::CXXBindTemporaryExprClass: {
1350  auto *BTE = cast<CXXBindTemporaryExpr>(Child);
1351  findConstructionContexts(withExtraLayer(BTE), BTE->getSubExpr());
1352  break;
1353  }
1354  case Stmt::MaterializeTemporaryExprClass: {
1355  // Normally we don't want to search in MaterializeTemporaryExpr because
1356  // it indicates the beginning of a temporary object construction context,
1357  // so it shouldn't be found in the middle. However, if it is the beginning
1358  // of an elidable copy or move construction context, we need to include it.
1359  if (Layer->getItem().getKind() ==
1361  auto *MTE = cast<MaterializeTemporaryExpr>(Child);
1362  findConstructionContexts(withExtraLayer(MTE), MTE->GetTemporaryExpr());
1363  }
1364  break;
1365  }
1366  case Stmt::ConditionalOperatorClass: {
1367  auto *CO = cast<ConditionalOperator>(Child);
1368  if (Layer->getItem().getKind() !=
1370  // If the object returned by the conditional operator is not going to be a
1371  // temporary object that needs to be immediately materialized, then
1372  // it must be C++17 with its mandatory copy elision. Do not yet promise
1373  // to support this case.
1374  assert(!CO->getType()->getAsCXXRecordDecl() || CO->isGLValue() ||
1375  Context->getLangOpts().CPlusPlus17);
1376  break;
1377  }
1378  findConstructionContexts(Layer, CO->getLHS());
1379  findConstructionContexts(Layer, CO->getRHS());
1380  break;
1381  }
1382  default:
1383  break;
1384  }
1385 }
1386 
1387 void CFGBuilder::cleanupConstructionContext(Expr *E) {
1388  assert(BuildOpts.AddRichCXXConstructors &&
1389  "We should not be managing construction contexts!");
1390  assert(ConstructionContextMap.count(E) &&
1391  "Cannot exit construction context without the context!");
1392  ConstructionContextMap.erase(E);
1393 }
1394 
1395 
1396 /// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an
1397 /// arbitrary statement. Examples include a single expression or a function
1398 /// body (compound statement). The ownership of the returned CFG is
1399 /// transferred to the caller. If CFG construction fails, this method returns
1400 /// NULL.
1401 std::unique_ptr<CFG> CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) {
1402  assert(cfg.get());
1403  if (!Statement)
1404  return nullptr;
1405 
1406  // Create an empty block that will serve as the exit block for the CFG. Since
1407  // this is the first block added to the CFG, it will be implicitly registered
1408  // as the exit block.
1409  Succ = createBlock();
1410  assert(Succ == &cfg->getExit());
1411  Block = nullptr; // the EXIT block is empty. Create all other blocks lazily.
1412 
1413  assert(!(BuildOpts.AddImplicitDtors && BuildOpts.AddLifetime) &&
1414  "AddImplicitDtors and AddLifetime cannot be used at the same time");
1415 
1416  if (BuildOpts.AddImplicitDtors)
1417  if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D))
1418  addImplicitDtorsForDestructor(DD);
1419 
1420  // Visit the statements and create the CFG.
1421  CFGBlock *B = addStmt(Statement);
1422 
1423  if (badCFG)
1424  return nullptr;
1425 
1426  // For C++ constructor add initializers to CFG.
1427  if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) {
1428  for (auto *I : llvm::reverse(CD->inits())) {
1429  B = addInitializer(I);
1430  if (badCFG)
1431  return nullptr;
1432  }
1433  }
1434 
1435  if (B)
1436  Succ = B;
1437 
1438  // Backpatch the gotos whose label -> block mappings we didn't know when we
1439  // encountered them.
1440  for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(),
1441  E = BackpatchBlocks.end(); I != E; ++I ) {
1442 
1443  CFGBlock *B = I->block;
1444  const GotoStmt *G = cast<GotoStmt>(B->getTerminator());
1445  LabelMapTy::iterator LI = LabelMap.find(G->getLabel());
1446 
1447  // If there is no target for the goto, then we are looking at an
1448  // incomplete AST. Handle this by not registering a successor.
1449  if (LI == LabelMap.end()) continue;
1450 
1451  JumpTarget JT = LI->second;
1452  prependAutomaticObjLifetimeWithTerminator(B, I->scopePosition,
1453  JT.scopePosition);
1454  prependAutomaticObjDtorsWithTerminator(B, I->scopePosition,
1455  JT.scopePosition);
1456  const VarDecl *VD = prependAutomaticObjScopeEndWithTerminator(
1457  B, I->scopePosition, JT.scopePosition);
1458  appendScopeBegin(JT.block, VD, G);
1459  addSuccessor(B, JT.block);
1460  }
1461 
1462  // Add successors to the Indirect Goto Dispatch block (if we have one).
1463  if (CFGBlock *B = cfg->getIndirectGotoBlock())
1464  for (LabelSetTy::iterator I = AddressTakenLabels.begin(),
1465  E = AddressTakenLabels.end(); I != E; ++I ) {
1466  // Lookup the target block.
1467  LabelMapTy::iterator LI = LabelMap.find(*I);
1468 
1469  // If there is no target block that contains label, then we are looking
1470  // at an incomplete AST. Handle this by not registering a successor.
1471  if (LI == LabelMap.end()) continue;
1472 
1473  addSuccessor(B, LI->second.block);
1474  }
1475 
1476  // Create an empty entry block that has no predecessors.
1477  cfg->setEntry(createBlock());
1478 
1479  if (BuildOpts.AddRichCXXConstructors)
1480  assert(ConstructionContextMap.empty() &&
1481  "Not all construction contexts were cleaned up!");
1482 
1483  return std::move(cfg);
1484 }
1485 
1486 /// createBlock - Used to lazily create blocks that are connected
1487 /// to the current (global) succcessor.
1488 CFGBlock *CFGBuilder::createBlock(bool add_successor) {
1489  CFGBlock *B = cfg->createBlock();
1490  if (add_successor && Succ)
1491  addSuccessor(B, Succ);
1492  return B;
1493 }
1494 
1495 /// createNoReturnBlock - Used to create a block is a 'noreturn' point in the
1496 /// CFG. It is *not* connected to the current (global) successor, and instead
1497 /// directly tied to the exit block in order to be reachable.
1498 CFGBlock *CFGBuilder::createNoReturnBlock() {
1499  CFGBlock *B = createBlock(false);
1500  B->setHasNoReturnElement();
1501  addSuccessor(B, &cfg->getExit(), Succ);
1502  return B;
1503 }
1504 
1505 /// addInitializer - Add C++ base or member initializer element to CFG.
1506 CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) {
1507  if (!BuildOpts.AddInitializers)
1508  return Block;
1509 
1510  bool HasTemporaries = false;
1511 
1512  // Destructors of temporaries in initialization expression should be called
1513  // after initialization finishes.
1514  Expr *Init = I->getInit();
1515  if (Init) {
1516  HasTemporaries = isa<ExprWithCleanups>(Init);
1517 
1518  if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
1519  // Generate destructors for temporaries in initialization expression.
1520  TempDtorContext Context;
1521  VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
1522  /*BindToTemporary=*/false, Context);
1523  }
1524  }
1525 
1526  autoCreateBlock();
1527  appendInitializer(Block, I);
1528 
1529  if (Init) {
1530  findConstructionContexts(
1531  ConstructionContextLayer::create(cfg->getBumpVectorContext(), I),
1532  Init);
1533 
1534  if (HasTemporaries) {
1535  // For expression with temporaries go directly to subexpression to omit
1536  // generating destructors for the second time.
1537  return Visit(cast<ExprWithCleanups>(Init)->getSubExpr());
1538  }
1539  if (BuildOpts.AddCXXDefaultInitExprInCtors) {
1540  if (CXXDefaultInitExpr *Default = dyn_cast<CXXDefaultInitExpr>(Init)) {
1541  // In general, appending the expression wrapped by a CXXDefaultInitExpr
1542  // may cause the same Expr to appear more than once in the CFG. Doing it
1543  // here is safe because there's only one initializer per field.
1544  autoCreateBlock();
1545  appendStmt(Block, Default);
1546  if (Stmt *Child = Default->getExpr())
1547  if (CFGBlock *R = Visit(Child))
1548  Block = R;
1549  return Block;
1550  }
1551  }
1552  return Visit(Init);
1553  }
1554 
1555  return Block;
1556 }
1557 
1558 /// Retrieve the type of the temporary object whose lifetime was
1559 /// extended by a local reference with the given initializer.
1561  bool *FoundMTE = nullptr) {
1562  while (true) {
1563  // Skip parentheses.
1564  Init = Init->IgnoreParens();
1565 
1566  // Skip through cleanups.
1567  if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Init)) {
1568  Init = EWC->getSubExpr();
1569  continue;
1570  }
1571 
1572  // Skip through the temporary-materialization expression.
1573  if (const MaterializeTemporaryExpr *MTE
1574  = dyn_cast<MaterializeTemporaryExpr>(Init)) {
1575  Init = MTE->GetTemporaryExpr();
1576  if (FoundMTE)
1577  *FoundMTE = true;
1578  continue;
1579  }
1580 
1581  // Skip sub-object accesses into rvalues.
1582  SmallVector<const Expr *, 2> CommaLHSs;
1584  const Expr *SkippedInit =
1585  Init->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
1586  if (SkippedInit != Init) {
1587  Init = SkippedInit;
1588  continue;
1589  }
1590 
1591  break;
1592  }
1593 
1594  return Init->getType();
1595 }
1596 
1597 // TODO: Support adding LoopExit element to the CFG in case where the loop is
1598 // ended by ReturnStmt, GotoStmt or ThrowExpr.
1599 void CFGBuilder::addLoopExit(const Stmt *LoopStmt){
1600  if(!BuildOpts.AddLoopExit)
1601  return;
1602  autoCreateBlock();
1603  appendLoopExit(Block, LoopStmt);
1604 }
1605 
1606 void CFGBuilder::getDeclsWithEndedScope(LocalScope::const_iterator B,
1607  LocalScope::const_iterator E, Stmt *S) {
1608  if (!BuildOpts.AddScopes)
1609  return;
1610 
1611  if (B == E)
1612  return;
1613 
1614  // To go from B to E, one first goes up the scopes from B to P
1615  // then sideways in one scope from P to P' and then down
1616  // the scopes from P' to E.
1617  // The lifetime of all objects between B and P end.
1618  LocalScope::const_iterator P = B.shared_parent(E);
1619  int Dist = B.distance(P);
1620  if (Dist <= 0)
1621  return;
1622 
1623  for (LocalScope::const_iterator I = B; I != P; ++I)
1624  if (I.pointsToFirstDeclaredVar())
1625  DeclsWithEndedScope.insert(*I);
1626 }
1627 
1628 void CFGBuilder::addAutomaticObjHandling(LocalScope::const_iterator B,
1629  LocalScope::const_iterator E,
1630  Stmt *S) {
1631  getDeclsWithEndedScope(B, E, S);
1632  if (BuildOpts.AddScopes)
1633  addScopesEnd(B, E, S);
1634  if (BuildOpts.AddImplicitDtors)
1635  addAutomaticObjDtors(B, E, S);
1636  if (BuildOpts.AddLifetime)
1637  addLifetimeEnds(B, E, S);
1638 }
1639 
1640 /// Add to current block automatic objects that leave the scope.
1641 void CFGBuilder::addLifetimeEnds(LocalScope::const_iterator B,
1642  LocalScope::const_iterator E, Stmt *S) {
1643  if (!BuildOpts.AddLifetime)
1644  return;
1645 
1646  if (B == E)
1647  return;
1648 
1649  // To go from B to E, one first goes up the scopes from B to P
1650  // then sideways in one scope from P to P' and then down
1651  // the scopes from P' to E.
1652  // The lifetime of all objects between B and P end.
1653  LocalScope::const_iterator P = B.shared_parent(E);
1654  int dist = B.distance(P);
1655  if (dist <= 0)
1656  return;
1657 
1658  // We need to perform the scope leaving in reverse order
1659  SmallVector<VarDecl *, 10> DeclsTrivial;
1660  SmallVector<VarDecl *, 10> DeclsNonTrivial;
1661  DeclsTrivial.reserve(dist);
1662  DeclsNonTrivial.reserve(dist);
1663 
1664  for (LocalScope::const_iterator I = B; I != P; ++I)
1665  if (hasTrivialDestructor(*I))
1666  DeclsTrivial.push_back(*I);
1667  else
1668  DeclsNonTrivial.push_back(*I);
1669 
1670  autoCreateBlock();
1671  // object with trivial destructor end their lifetime last (when storage
1672  // duration ends)
1673  for (SmallVectorImpl<VarDecl *>::reverse_iterator I = DeclsTrivial.rbegin(),
1674  E = DeclsTrivial.rend();
1675  I != E; ++I)
1676  appendLifetimeEnds(Block, *I, S);
1677 
1679  I = DeclsNonTrivial.rbegin(),
1680  E = DeclsNonTrivial.rend();
1681  I != E; ++I)
1682  appendLifetimeEnds(Block, *I, S);
1683 }
1684 
1685 /// Add to current block markers for ending scopes.
1686 void CFGBuilder::addScopesEnd(LocalScope::const_iterator B,
1687  LocalScope::const_iterator E, Stmt *S) {
1688  // If implicit destructors are enabled, we'll add scope ends in
1689  // addAutomaticObjDtors.
1690  if (BuildOpts.AddImplicitDtors)
1691  return;
1692 
1693  autoCreateBlock();
1694 
1695  for (auto I = DeclsWithEndedScope.rbegin(), E = DeclsWithEndedScope.rend();
1696  I != E; ++I)
1697  appendScopeEnd(Block, *I, S);
1698 
1699  return;
1700 }
1701 
1702 /// addAutomaticObjDtors - Add to current block automatic objects destructors
1703 /// for objects in range of local scope positions. Use S as trigger statement
1704 /// for destructors.
1705 void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B,
1706  LocalScope::const_iterator E, Stmt *S) {
1707  if (!BuildOpts.AddImplicitDtors)
1708  return;
1709 
1710  if (B == E)
1711  return;
1712 
1713  // We need to append the destructors in reverse order, but any one of them
1714  // may be a no-return destructor which changes the CFG. As a result, buffer
1715  // this sequence up and replay them in reverse order when appending onto the
1716  // CFGBlock(s).
1718  Decls.reserve(B.distance(E));
1719  for (LocalScope::const_iterator I = B; I != E; ++I)
1720  Decls.push_back(*I);
1721 
1722  for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(),
1723  E = Decls.rend();
1724  I != E; ++I) {
1725  if (hasTrivialDestructor(*I)) {
1726  // If AddScopes is enabled and *I is a first variable in a scope, add a
1727  // ScopeEnd marker in a Block.
1728  if (BuildOpts.AddScopes && DeclsWithEndedScope.count(*I)) {
1729  autoCreateBlock();
1730  appendScopeEnd(Block, *I, S);
1731  }
1732  continue;
1733  }
1734  // If this destructor is marked as a no-return destructor, we need to
1735  // create a new block for the destructor which does not have as a successor
1736  // anything built thus far: control won't flow out of this block.
1737  QualType Ty = (*I)->getType();
1738  if (Ty->isReferenceType()) {
1739  Ty = getReferenceInitTemporaryType((*I)->getInit());
1740  }
1741  Ty = Context->getBaseElementType(Ty);
1742 
1743  if (Ty->getAsCXXRecordDecl()->isAnyDestructorNoReturn())
1744  Block = createNoReturnBlock();
1745  else
1746  autoCreateBlock();
1747 
1748  // Add ScopeEnd just after automatic obj destructor.
1749  if (BuildOpts.AddScopes && DeclsWithEndedScope.count(*I))
1750  appendScopeEnd(Block, *I, S);
1751  appendAutomaticObjDtor(Block, *I, S);
1752  }
1753 }
1754 
1755 /// addImplicitDtorsForDestructor - Add implicit destructors generated for
1756 /// base and member objects in destructor.
1757 void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) {
1758  assert(BuildOpts.AddImplicitDtors &&
1759  "Can be called only when dtors should be added");
1760  const CXXRecordDecl *RD = DD->getParent();
1761 
1762  // At the end destroy virtual base objects.
1763  for (const auto &VI : RD->vbases()) {
1764  const CXXRecordDecl *CD = VI.getType()->getAsCXXRecordDecl();
1765  if (!CD->hasTrivialDestructor()) {
1766  autoCreateBlock();
1767  appendBaseDtor(Block, &VI);
1768  }
1769  }
1770 
1771  // Before virtual bases destroy direct base objects.
1772  for (const auto &BI : RD->bases()) {
1773  if (!BI.isVirtual()) {
1774  const CXXRecordDecl *CD = BI.getType()->getAsCXXRecordDecl();
1775  if (!CD->hasTrivialDestructor()) {
1776  autoCreateBlock();
1777  appendBaseDtor(Block, &BI);
1778  }
1779  }
1780  }
1781 
1782  // First destroy member objects.
1783  for (auto *FI : RD->fields()) {
1784  // Check for constant size array. Set type to array element type.
1785  QualType QT = FI->getType();
1786  if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
1787  if (AT->getSize() == 0)
1788  continue;
1789  QT = AT->getElementType();
1790  }
1791 
1792  if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
1793  if (!CD->hasTrivialDestructor()) {
1794  autoCreateBlock();
1795  appendMemberDtor(Block, FI);
1796  }
1797  }
1798 }
1799 
1800 /// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either
1801 /// way return valid LocalScope object.
1802 LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) {
1803  if (Scope)
1804  return Scope;
1805  llvm::BumpPtrAllocator &alloc = cfg->getAllocator();
1806  return new (alloc.Allocate<LocalScope>())
1807  LocalScope(BumpVectorContext(alloc), ScopePos);
1808 }
1809 
1810 /// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement
1811 /// that should create implicit scope (e.g. if/else substatements).
1812 void CFGBuilder::addLocalScopeForStmt(Stmt *S) {
1813  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1814  !BuildOpts.AddScopes)
1815  return;
1816 
1817  LocalScope *Scope = nullptr;
1818 
1819  // For compound statement we will be creating explicit scope.
1820  if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
1821  for (auto *BI : CS->body()) {
1822  Stmt *SI = BI->stripLabelLikeStatements();
1823  if (DeclStmt *DS = dyn_cast<DeclStmt>(SI))
1824  Scope = addLocalScopeForDeclStmt(DS, Scope);
1825  }
1826  return;
1827  }
1828 
1829  // For any other statement scope will be implicit and as such will be
1830  // interesting only for DeclStmt.
1831  if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements()))
1832  addLocalScopeForDeclStmt(DS);
1833 }
1834 
1835 /// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will
1836 /// reuse Scope if not NULL.
1837 LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS,
1838  LocalScope* Scope) {
1839  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1840  !BuildOpts.AddScopes)
1841  return Scope;
1842 
1843  for (auto *DI : DS->decls())
1844  if (VarDecl *VD = dyn_cast<VarDecl>(DI))
1845  Scope = addLocalScopeForVarDecl(VD, Scope);
1846  return Scope;
1847 }
1848 
1849 bool CFGBuilder::hasTrivialDestructor(VarDecl *VD) {
1850  // Check for const references bound to temporary. Set type to pointee.
1851  QualType QT = VD->getType();
1852  if (QT->isReferenceType()) {
1853  // Attempt to determine whether this declaration lifetime-extends a
1854  // temporary.
1855  //
1856  // FIXME: This is incorrect. Non-reference declarations can lifetime-extend
1857  // temporaries, and a single declaration can extend multiple temporaries.
1858  // We should look at the storage duration on each nested
1859  // MaterializeTemporaryExpr instead.
1860 
1861  const Expr *Init = VD->getInit();
1862  if (!Init) {
1863  // Probably an exception catch-by-reference variable.
1864  // FIXME: It doesn't really mean that the object has a trivial destructor.
1865  // Also are there other cases?
1866  return true;
1867  }
1868 
1869  // Lifetime-extending a temporary?
1870  bool FoundMTE = false;
1871  QT = getReferenceInitTemporaryType(Init, &FoundMTE);
1872  if (!FoundMTE)
1873  return true;
1874  }
1875 
1876  // Check for constant size array. Set type to array element type.
1877  while (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
1878  if (AT->getSize() == 0)
1879  return true;
1880  QT = AT->getElementType();
1881  }
1882 
1883  // Check if type is a C++ class with non-trivial destructor.
1884  if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
1885  return !CD->hasDefinition() || CD->hasTrivialDestructor();
1886  return true;
1887 }
1888 
1889 /// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will
1890 /// create add scope for automatic objects and temporary objects bound to
1891 /// const reference. Will reuse Scope if not NULL.
1892 LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD,
1893  LocalScope* Scope) {
1894  assert(!(BuildOpts.AddImplicitDtors && BuildOpts.AddLifetime) &&
1895  "AddImplicitDtors and AddLifetime cannot be used at the same time");
1896  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1897  !BuildOpts.AddScopes)
1898  return Scope;
1899 
1900  // Check if variable is local.
1901  switch (VD->getStorageClass()) {
1902  case SC_None:
1903  case SC_Auto:
1904  case SC_Register:
1905  break;
1906  default: return Scope;
1907  }
1908 
1909  if (BuildOpts.AddImplicitDtors) {
1910  if (!hasTrivialDestructor(VD) || BuildOpts.AddScopes) {
1911  // Add the variable to scope
1912  Scope = createOrReuseLocalScope(Scope);
1913  Scope->addVar(VD);
1914  ScopePos = Scope->begin();
1915  }
1916  return Scope;
1917  }
1918 
1919  assert(BuildOpts.AddLifetime);
1920  // Add the variable to scope
1921  Scope = createOrReuseLocalScope(Scope);
1922  Scope->addVar(VD);
1923  ScopePos = Scope->begin();
1924  return Scope;
1925 }
1926 
1927 /// addLocalScopeAndDtors - For given statement add local scope for it and
1928 /// add destructors that will cleanup the scope. Will reuse Scope if not NULL.
1929 void CFGBuilder::addLocalScopeAndDtors(Stmt *S) {
1930  LocalScope::const_iterator scopeBeginPos = ScopePos;
1931  addLocalScopeForStmt(S);
1932  addAutomaticObjHandling(ScopePos, scopeBeginPos, S);
1933 }
1934 
1935 /// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for
1936 /// variables with automatic storage duration to CFGBlock's elements vector.
1937 /// Elements will be prepended to physical beginning of the vector which
1938 /// happens to be logical end. Use blocks terminator as statement that specifies
1939 /// destructors call site.
1940 /// FIXME: This mechanism for adding automatic destructors doesn't handle
1941 /// no-return destructors properly.
1942 void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
1943  LocalScope::const_iterator B, LocalScope::const_iterator E) {
1944  if (!BuildOpts.AddImplicitDtors)
1945  return;
1946  BumpVectorContext &C = cfg->getBumpVectorContext();
1947  CFGBlock::iterator InsertPos
1948  = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C);
1949  for (LocalScope::const_iterator I = B; I != E; ++I)
1950  InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I,
1951  Blk->getTerminator());
1952 }
1953 
1954 /// prependAutomaticObjLifetimeWithTerminator - Prepend lifetime CFGElements for
1955 /// variables with automatic storage duration to CFGBlock's elements vector.
1956 /// Elements will be prepended to physical beginning of the vector which
1957 /// happens to be logical end. Use blocks terminator as statement that specifies
1958 /// where lifetime ends.
1959 void CFGBuilder::prependAutomaticObjLifetimeWithTerminator(
1960  CFGBlock *Blk, LocalScope::const_iterator B, LocalScope::const_iterator E) {
1961  if (!BuildOpts.AddLifetime)
1962  return;
1963  BumpVectorContext &C = cfg->getBumpVectorContext();
1964  CFGBlock::iterator InsertPos =
1965  Blk->beginLifetimeEndsInsert(Blk->end(), B.distance(E), C);
1966  for (LocalScope::const_iterator I = B; I != E; ++I)
1967  InsertPos = Blk->insertLifetimeEnds(InsertPos, *I, Blk->getTerminator());
1968 }
1969 
1970 /// prependAutomaticObjScopeEndWithTerminator - Prepend scope end CFGElements for
1971 /// variables with automatic storage duration to CFGBlock's elements vector.
1972 /// Elements will be prepended to physical beginning of the vector which
1973 /// happens to be logical end. Use blocks terminator as statement that specifies
1974 /// where scope ends.
1975 const VarDecl *
1976 CFGBuilder::prependAutomaticObjScopeEndWithTerminator(
1977  CFGBlock *Blk, LocalScope::const_iterator B, LocalScope::const_iterator E) {
1978  if (!BuildOpts.AddScopes)
1979  return nullptr;
1980  BumpVectorContext &C = cfg->getBumpVectorContext();
1981  CFGBlock::iterator InsertPos =
1982  Blk->beginScopeEndInsert(Blk->end(), 1, C);
1983  LocalScope::const_iterator PlaceToInsert = B;
1984  for (LocalScope::const_iterator I = B; I != E; ++I)
1985  PlaceToInsert = I;
1986  Blk->insertScopeEnd(InsertPos, *PlaceToInsert, Blk->getTerminator());
1987  return *PlaceToInsert;
1988 }
1989 
1990 /// Visit - Walk the subtree of a statement and add extra
1991 /// blocks for ternary operators, &&, and ||. We also process "," and
1992 /// DeclStmts (which may contain nested control-flow).
1993 CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) {
1994  if (!S) {
1995  badCFG = true;
1996  return nullptr;
1997  }
1998 
1999  if (Expr *E = dyn_cast<Expr>(S))
2000  S = E->IgnoreParens();
2001 
2002  switch (S->getStmtClass()) {
2003  default:
2004  return VisitStmt(S, asc);
2005 
2006  case Stmt::AddrLabelExprClass:
2007  return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc);
2008 
2009  case Stmt::BinaryConditionalOperatorClass:
2010  return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc);
2011 
2012  case Stmt::BinaryOperatorClass:
2013  return VisitBinaryOperator(cast<BinaryOperator>(S), asc);
2014 
2015  case Stmt::BlockExprClass:
2016  return VisitBlockExpr(cast<BlockExpr>(S), asc);
2017 
2018  case Stmt::BreakStmtClass:
2019  return VisitBreakStmt(cast<BreakStmt>(S));
2020 
2021  case Stmt::CallExprClass:
2022  case Stmt::CXXOperatorCallExprClass:
2023  case Stmt::CXXMemberCallExprClass:
2024  case Stmt::UserDefinedLiteralClass:
2025  return VisitCallExpr(cast<CallExpr>(S), asc);
2026 
2027  case Stmt::CaseStmtClass:
2028  return VisitCaseStmt(cast<CaseStmt>(S));
2029 
2030  case Stmt::ChooseExprClass:
2031  return VisitChooseExpr(cast<ChooseExpr>(S), asc);
2032 
2033  case Stmt::CompoundStmtClass:
2034  return VisitCompoundStmt(cast<CompoundStmt>(S));
2035 
2036  case Stmt::ConditionalOperatorClass:
2037  return VisitConditionalOperator(cast<ConditionalOperator>(S), asc);
2038 
2039  case Stmt::ContinueStmtClass:
2040  return VisitContinueStmt(cast<ContinueStmt>(S));
2041 
2042  case Stmt::CXXCatchStmtClass:
2043  return VisitCXXCatchStmt(cast<CXXCatchStmt>(S));
2044 
2045  case Stmt::ExprWithCleanupsClass:
2046  return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc);
2047 
2048  case Stmt::CXXDefaultArgExprClass:
2049  case Stmt::CXXDefaultInitExprClass:
2050  // FIXME: The expression inside a CXXDefaultArgExpr is owned by the
2051  // called function's declaration, not by the caller. If we simply add
2052  // this expression to the CFG, we could end up with the same Expr
2053  // appearing multiple times.
2054  // PR13385 / <rdar://problem/12156507>
2055  //
2056  // It's likewise possible for multiple CXXDefaultInitExprs for the same
2057  // expression to be used in the same function (through aggregate
2058  // initialization).
2059  return VisitStmt(S, asc);
2060 
2061  case Stmt::CXXBindTemporaryExprClass:
2062  return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc);
2063 
2064  case Stmt::CXXConstructExprClass:
2065  return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc);
2066 
2067  case Stmt::CXXNewExprClass:
2068  return VisitCXXNewExpr(cast<CXXNewExpr>(S), asc);
2069 
2070  case Stmt::CXXDeleteExprClass:
2071  return VisitCXXDeleteExpr(cast<CXXDeleteExpr>(S), asc);
2072 
2073  case Stmt::CXXFunctionalCastExprClass:
2074  return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc);
2075 
2076  case Stmt::CXXTemporaryObjectExprClass:
2077  return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc);
2078 
2079  case Stmt::CXXThrowExprClass:
2080  return VisitCXXThrowExpr(cast<CXXThrowExpr>(S));
2081 
2082  case Stmt::CXXTryStmtClass:
2083  return VisitCXXTryStmt(cast<CXXTryStmt>(S));
2084 
2085  case Stmt::CXXForRangeStmtClass:
2086  return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S));
2087 
2088  case Stmt::DeclStmtClass:
2089  return VisitDeclStmt(cast<DeclStmt>(S));
2090 
2091  case Stmt::DefaultStmtClass:
2092  return VisitDefaultStmt(cast<DefaultStmt>(S));
2093 
2094  case Stmt::DoStmtClass:
2095  return VisitDoStmt(cast<DoStmt>(S));
2096 
2097  case Stmt::ForStmtClass:
2098  return VisitForStmt(cast<ForStmt>(S));
2099 
2100  case Stmt::GotoStmtClass:
2101  return VisitGotoStmt(cast<GotoStmt>(S));
2102 
2103  case Stmt::IfStmtClass:
2104  return VisitIfStmt(cast<IfStmt>(S));
2105 
2106  case Stmt::ImplicitCastExprClass:
2107  return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc);
2108 
2109  case Stmt::ConstantExprClass:
2110  return VisitConstantExpr(cast<ConstantExpr>(S), asc);
2111 
2112  case Stmt::IndirectGotoStmtClass:
2113  return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S));
2114 
2115  case Stmt::LabelStmtClass:
2116  return VisitLabelStmt(cast<LabelStmt>(S));
2117 
2118  case Stmt::LambdaExprClass:
2119  return VisitLambdaExpr(cast<LambdaExpr>(S), asc);
2120 
2121  case Stmt::MaterializeTemporaryExprClass:
2122  return VisitMaterializeTemporaryExpr(cast<MaterializeTemporaryExpr>(S),
2123  asc);
2124 
2125  case Stmt::MemberExprClass:
2126  return VisitMemberExpr(cast<MemberExpr>(S), asc);
2127 
2128  case Stmt::NullStmtClass:
2129  return Block;
2130 
2131  case Stmt::ObjCAtCatchStmtClass:
2132  return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S));
2133 
2134  case Stmt::ObjCAutoreleasePoolStmtClass:
2135  return VisitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(S));
2136 
2137  case Stmt::ObjCAtSynchronizedStmtClass:
2138  return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S));
2139 
2140  case Stmt::ObjCAtThrowStmtClass:
2141  return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S));
2142 
2143  case Stmt::ObjCAtTryStmtClass:
2144  return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S));
2145 
2146  case Stmt::ObjCForCollectionStmtClass:
2147  return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S));
2148 
2149  case Stmt::ObjCMessageExprClass:
2150  return VisitObjCMessageExpr(cast<ObjCMessageExpr>(S), asc);
2151 
2152  case Stmt::OpaqueValueExprClass:
2153  return Block;
2154 
2155  case Stmt::PseudoObjectExprClass:
2156  return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S));
2157 
2158  case Stmt::ReturnStmtClass:
2159  case Stmt::CoreturnStmtClass:
2160  return VisitReturnStmt(S);
2161 
2162  case Stmt::SEHExceptStmtClass:
2163  return VisitSEHExceptStmt(cast<SEHExceptStmt>(S));
2164 
2165  case Stmt::SEHFinallyStmtClass:
2166  return VisitSEHFinallyStmt(cast<SEHFinallyStmt>(S));
2167 
2168  case Stmt::SEHLeaveStmtClass:
2169  return VisitSEHLeaveStmt(cast<SEHLeaveStmt>(S));
2170 
2171  case Stmt::SEHTryStmtClass:
2172  return VisitSEHTryStmt(cast<SEHTryStmt>(S));
2173 
2174  case Stmt::UnaryExprOrTypeTraitExprClass:
2175  return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S),
2176  asc);
2177 
2178  case Stmt::StmtExprClass:
2179  return VisitStmtExpr(cast<StmtExpr>(S), asc);
2180 
2181  case Stmt::SwitchStmtClass:
2182  return VisitSwitchStmt(cast<SwitchStmt>(S));
2183 
2184  case Stmt::UnaryOperatorClass:
2185  return VisitUnaryOperator(cast<UnaryOperator>(S), asc);
2186 
2187  case Stmt::WhileStmtClass:
2188  return VisitWhileStmt(cast<WhileStmt>(S));
2189  }
2190 }
2191 
2192 CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) {
2193  if (asc.alwaysAdd(*this, S)) {
2194  autoCreateBlock();
2195  appendStmt(Block, S);
2196  }
2197 
2198  return VisitChildren(S);
2199 }
2200 
2201 /// VisitChildren - Visit the children of a Stmt.
2202 CFGBlock *CFGBuilder::VisitChildren(Stmt *S) {
2203  CFGBlock *B = Block;
2204 
2205  // Visit the children in their reverse order so that they appear in
2206  // left-to-right (natural) order in the CFG.
2207  reverse_children RChildren(S);
2208  for (reverse_children::iterator I = RChildren.begin(), E = RChildren.end();
2209  I != E; ++I) {
2210  if (Stmt *Child = *I)
2211  if (CFGBlock *R = Visit(Child))
2212  B = R;
2213  }
2214  return B;
2215 }
2216 
2217 CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A,
2218  AddStmtChoice asc) {
2219  AddressTakenLabels.insert(A->getLabel());
2220 
2221  if (asc.alwaysAdd(*this, A)) {
2222  autoCreateBlock();
2223  appendStmt(Block, A);
2224  }
2225 
2226  return Block;
2227 }
2228 
2229 CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U,
2230  AddStmtChoice asc) {
2231  if (asc.alwaysAdd(*this, U)) {
2232  autoCreateBlock();
2233  appendStmt(Block, U);
2234  }
2235 
2236  return Visit(U->getSubExpr(), AddStmtChoice());
2237 }
2238 
2239 CFGBlock *CFGBuilder::VisitLogicalOperator(BinaryOperator *B) {
2240  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2241  appendStmt(ConfluenceBlock, B);
2242 
2243  if (badCFG)
2244  return nullptr;
2245 
2246  return VisitLogicalOperator(B, nullptr, ConfluenceBlock,
2247  ConfluenceBlock).first;
2248 }
2249 
2250 std::pair<CFGBlock*, CFGBlock*>
2251 CFGBuilder::VisitLogicalOperator(BinaryOperator *B,
2252  Stmt *Term,
2253  CFGBlock *TrueBlock,
2254  CFGBlock *FalseBlock) {
2255  // Introspect the RHS. If it is a nested logical operation, we recursively
2256  // build the CFG using this function. Otherwise, resort to default
2257  // CFG construction behavior.
2258  Expr *RHS = B->getRHS()->IgnoreParens();
2259  CFGBlock *RHSBlock, *ExitBlock;
2260 
2261  do {
2262  if (BinaryOperator *B_RHS = dyn_cast<BinaryOperator>(RHS))
2263  if (B_RHS->isLogicalOp()) {
2264  std::tie(RHSBlock, ExitBlock) =
2265  VisitLogicalOperator(B_RHS, Term, TrueBlock, FalseBlock);
2266  break;
2267  }
2268 
2269  // The RHS is not a nested logical operation. Don't push the terminator
2270  // down further, but instead visit RHS and construct the respective
2271  // pieces of the CFG, and link up the RHSBlock with the terminator
2272  // we have been provided.
2273  ExitBlock = RHSBlock = createBlock(false);
2274 
2275  // Even though KnownVal is only used in the else branch of the next
2276  // conditional, tryEvaluateBool performs additional checking on the
2277  // Expr, so it should be called unconditionally.
2278  TryResult KnownVal = tryEvaluateBool(RHS);
2279  if (!KnownVal.isKnown())
2280  KnownVal = tryEvaluateBool(B);
2281 
2282  if (!Term) {
2283  assert(TrueBlock == FalseBlock);
2284  addSuccessor(RHSBlock, TrueBlock);
2285  }
2286  else {
2287  RHSBlock->setTerminator(Term);
2288  addSuccessor(RHSBlock, TrueBlock, !KnownVal.isFalse());
2289  addSuccessor(RHSBlock, FalseBlock, !KnownVal.isTrue());
2290  }
2291 
2292  Block = RHSBlock;
2293  RHSBlock = addStmt(RHS);
2294  }
2295  while (false);
2296 
2297  if (badCFG)
2298  return std::make_pair(nullptr, nullptr);
2299 
2300  // Generate the blocks for evaluating the LHS.
2301  Expr *LHS = B->getLHS()->IgnoreParens();
2302 
2303  if (BinaryOperator *B_LHS = dyn_cast<BinaryOperator>(LHS))
2304  if (B_LHS->isLogicalOp()) {
2305  if (B->getOpcode() == BO_LOr)
2306  FalseBlock = RHSBlock;
2307  else
2308  TrueBlock = RHSBlock;
2309 
2310  // For the LHS, treat 'B' as the terminator that we want to sink
2311  // into the nested branch. The RHS always gets the top-most
2312  // terminator.
2313  return VisitLogicalOperator(B_LHS, B, TrueBlock, FalseBlock);
2314  }
2315 
2316  // Create the block evaluating the LHS.
2317  // This contains the '&&' or '||' as the terminator.
2318  CFGBlock *LHSBlock = createBlock(false);
2319  LHSBlock->setTerminator(B);
2320 
2321  Block = LHSBlock;
2322  CFGBlock *EntryLHSBlock = addStmt(LHS);
2323 
2324  if (badCFG)
2325  return std::make_pair(nullptr, nullptr);
2326 
2327  // See if this is a known constant.
2328  TryResult KnownVal = tryEvaluateBool(LHS);
2329 
2330  // Now link the LHSBlock with RHSBlock.
2331  if (B->getOpcode() == BO_LOr) {
2332  addSuccessor(LHSBlock, TrueBlock, !KnownVal.isFalse());
2333  addSuccessor(LHSBlock, RHSBlock, !KnownVal.isTrue());
2334  } else {
2335  assert(B->getOpcode() == BO_LAnd);
2336  addSuccessor(LHSBlock, RHSBlock, !KnownVal.isFalse());
2337  addSuccessor(LHSBlock, FalseBlock, !KnownVal.isTrue());
2338  }
2339 
2340  return std::make_pair(EntryLHSBlock, ExitBlock);
2341 }
2342 
2343 CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B,
2344  AddStmtChoice asc) {
2345  // && or ||
2346  if (B->isLogicalOp())
2347  return VisitLogicalOperator(B);
2348 
2349  if (B->getOpcode() == BO_Comma) { // ,
2350  autoCreateBlock();
2351  appendStmt(Block, B);
2352  addStmt(B->getRHS());
2353  return addStmt(B->getLHS());
2354  }
2355 
2356  if (B->isAssignmentOp()) {
2357  if (asc.alwaysAdd(*this, B)) {
2358  autoCreateBlock();
2359  appendStmt(Block, B);
2360  }
2361  Visit(B->getLHS());
2362  return Visit(B->getRHS());
2363  }
2364 
2365  if (asc.alwaysAdd(*this, B)) {
2366  autoCreateBlock();
2367  appendStmt(Block, B);
2368  }
2369 
2370  CFGBlock *RBlock = Visit(B->getRHS());
2371  CFGBlock *LBlock = Visit(B->getLHS());
2372  // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr
2373  // containing a DoStmt, and the LHS doesn't create a new block, then we should
2374  // return RBlock. Otherwise we'll incorrectly return NULL.
2375  return (LBlock ? LBlock : RBlock);
2376 }
2377 
2378 CFGBlock *CFGBuilder::VisitNoRecurse(Expr *E, AddStmtChoice asc) {
2379  if (asc.alwaysAdd(*this, E)) {
2380  autoCreateBlock();
2381  appendStmt(Block, E);
2382  }
2383  return Block;
2384 }
2385 
2386 CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) {
2387  // "break" is a control-flow statement. Thus we stop processing the current
2388  // block.
2389  if (badCFG)
2390  return nullptr;
2391 
2392  // Now create a new block that ends with the break statement.
2393  Block = createBlock(false);
2394  Block->setTerminator(B);
2395 
2396  // If there is no target for the break, then we are looking at an incomplete
2397  // AST. This means that the CFG cannot be constructed.
2398  if (BreakJumpTarget.block) {
2399  addAutomaticObjHandling(ScopePos, BreakJumpTarget.scopePosition, B);
2400  addSuccessor(Block, BreakJumpTarget.block);
2401  } else
2402  badCFG = true;
2403 
2404  return Block;
2405 }
2406 
2407 static bool CanThrow(Expr *E, ASTContext &Ctx) {
2408  QualType Ty = E->getType();
2409  if (Ty->isFunctionPointerType())
2410  Ty = Ty->getAs<PointerType>()->getPointeeType();
2411  else if (Ty->isBlockPointerType())
2412  Ty = Ty->getAs<BlockPointerType>()->getPointeeType();
2413 
2414  const FunctionType *FT = Ty->getAs<FunctionType>();
2415  if (FT) {
2416  if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT))
2417  if (!isUnresolvedExceptionSpec(Proto->getExceptionSpecType()) &&
2418  Proto->isNothrow())
2419  return false;
2420  }
2421  return true;
2422 }
2423 
2424 CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) {
2425  // Compute the callee type.
2426  QualType calleeType = C->getCallee()->getType();
2427  if (calleeType == Context->BoundMemberTy) {
2428  QualType boundType = Expr::findBoundMemberType(C->getCallee());
2429 
2430  // We should only get a null bound type if processing a dependent
2431  // CFG. Recover by assuming nothing.
2432  if (!boundType.isNull()) calleeType = boundType;
2433  }
2434 
2435  // If this is a call to a no-return function, this stops the block here.
2436  bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn();
2437 
2438  bool AddEHEdge = false;
2439 
2440  // Languages without exceptions are assumed to not throw.
2441  if (Context->getLangOpts().Exceptions) {
2442  if (BuildOpts.AddEHEdges)
2443  AddEHEdge = true;
2444  }
2445 
2446  // If this is a call to a builtin function, it might not actually evaluate
2447  // its arguments. Don't add them to the CFG if this is the case.
2448  bool OmitArguments = false;
2449 
2450  if (FunctionDecl *FD = C->getDirectCallee()) {
2451  // TODO: Support construction contexts for variadic function arguments.
2452  // These are a bit problematic and not very useful because passing
2453  // C++ objects as C-style variadic arguments doesn't work in general
2454  // (see [expr.call]).
2455  if (!FD->isVariadic())
2456  findConstructionContextsForArguments(C);
2457 
2458  if (FD->isNoReturn() || C->isBuiltinAssumeFalse(*Context))
2459  NoReturn = true;
2460  if (FD->hasAttr<NoThrowAttr>())
2461  AddEHEdge = false;
2462  if (FD->getBuiltinID() == Builtin::BI__builtin_object_size)
2463  OmitArguments = true;
2464  }
2465 
2466  if (!CanThrow(C->getCallee(), *Context))
2467  AddEHEdge = false;
2468 
2469  if (OmitArguments) {
2470  assert(!NoReturn && "noreturn calls with unevaluated args not implemented");
2471  assert(!AddEHEdge && "EH calls with unevaluated args not implemented");
2472  autoCreateBlock();
2473  appendStmt(Block, C);
2474  return Visit(C->getCallee());
2475  }
2476 
2477  if (!NoReturn && !AddEHEdge) {
2478  autoCreateBlock();
2479  appendCall(Block, C);
2480 
2481  return VisitChildren(C);
2482  }
2483 
2484  if (Block) {
2485  Succ = Block;
2486  if (badCFG)
2487  return nullptr;
2488  }
2489 
2490  if (NoReturn)
2491  Block = createNoReturnBlock();
2492  else
2493  Block = createBlock();
2494 
2495  appendCall(Block, C);
2496 
2497  if (AddEHEdge) {
2498  // Add exceptional edges.
2499  if (TryTerminatedBlock)
2500  addSuccessor(Block, TryTerminatedBlock);
2501  else
2502  addSuccessor(Block, &cfg->getExit());
2503  }
2504 
2505  return VisitChildren(C);
2506 }
2507 
2508 CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C,
2509  AddStmtChoice asc) {
2510  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2511  appendStmt(ConfluenceBlock, C);
2512  if (badCFG)
2513  return nullptr;
2514 
2515  AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2516  Succ = ConfluenceBlock;
2517  Block = nullptr;
2518  CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd);
2519  if (badCFG)
2520  return nullptr;
2521 
2522  Succ = ConfluenceBlock;
2523  Block = nullptr;
2524  CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd);
2525  if (badCFG)
2526  return nullptr;
2527 
2528  Block = createBlock(false);
2529  // See if this is a known constant.
2530  const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2531  addSuccessor(Block, KnownVal.isFalse() ? nullptr : LHSBlock);
2532  addSuccessor(Block, KnownVal.isTrue() ? nullptr : RHSBlock);
2533  Block->setTerminator(C);
2534  return addStmt(C->getCond());
2535 }
2536 
2537 CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) {
2538  LocalScope::const_iterator scopeBeginPos = ScopePos;
2539  addLocalScopeForStmt(C);
2540 
2541  if (!C->body_empty() && !isa<ReturnStmt>(*C->body_rbegin())) {
2542  // If the body ends with a ReturnStmt, the dtors will be added in
2543  // VisitReturnStmt.
2544  addAutomaticObjHandling(ScopePos, scopeBeginPos, C);
2545  }
2546 
2547  CFGBlock *LastBlock = Block;
2548 
2550  I != E; ++I ) {
2551  // If we hit a segment of code just containing ';' (NullStmts), we can
2552  // get a null block back. In such cases, just use the LastBlock
2553  if (CFGBlock *newBlock = addStmt(*I))
2554  LastBlock = newBlock;
2555 
2556  if (badCFG)
2557  return nullptr;
2558  }
2559 
2560  return LastBlock;
2561 }
2562 
2563 CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C,
2564  AddStmtChoice asc) {
2565  const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C);
2566  const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : nullptr);
2567 
2568  // Create the confluence block that will "merge" the results of the ternary
2569  // expression.
2570  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2571  appendStmt(ConfluenceBlock, C);
2572  if (badCFG)
2573  return nullptr;
2574 
2575  AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2576 
2577  // Create a block for the LHS expression if there is an LHS expression. A
2578  // GCC extension allows LHS to be NULL, causing the condition to be the
2579  // value that is returned instead.
2580  // e.g: x ?: y is shorthand for: x ? x : y;
2581  Succ = ConfluenceBlock;
2582  Block = nullptr;
2583  CFGBlock *LHSBlock = nullptr;
2584  const Expr *trueExpr = C->getTrueExpr();
2585  if (trueExpr != opaqueValue) {
2586  LHSBlock = Visit(C->getTrueExpr(), alwaysAdd);
2587  if (badCFG)
2588  return nullptr;
2589  Block = nullptr;
2590  }
2591  else
2592  LHSBlock = ConfluenceBlock;
2593 
2594  // Create the block for the RHS expression.
2595  Succ = ConfluenceBlock;
2596  CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd);
2597  if (badCFG)
2598  return nullptr;
2599 
2600  // If the condition is a logical '&&' or '||', build a more accurate CFG.
2601  if (BinaryOperator *Cond =
2602  dyn_cast<BinaryOperator>(C->getCond()->IgnoreParens()))
2603  if (Cond->isLogicalOp())
2604  return VisitLogicalOperator(Cond, C, LHSBlock, RHSBlock).first;
2605 
2606  // Create the block that will contain the condition.
2607  Block = createBlock(false);
2608 
2609  // See if this is a known constant.
2610  const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2611  addSuccessor(Block, LHSBlock, !KnownVal.isFalse());
2612  addSuccessor(Block, RHSBlock, !KnownVal.isTrue());
2613  Block->setTerminator(C);
2614  Expr *condExpr = C->getCond();
2615 
2616  if (opaqueValue) {
2617  // Run the condition expression if it's not trivially expressed in
2618  // terms of the opaque value (or if there is no opaque value).
2619  if (condExpr != opaqueValue)
2620  addStmt(condExpr);
2621 
2622  // Before that, run the common subexpression if there was one.
2623  // At least one of this or the above will be run.
2624  return addStmt(BCO->getCommon());
2625  }
2626 
2627  return addStmt(condExpr);
2628 }
2629 
2630 CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) {
2631  // Check if the Decl is for an __label__. If so, elide it from the
2632  // CFG entirely.
2633  if (isa<LabelDecl>(*DS->decl_begin()))
2634  return Block;
2635 
2636  // This case also handles static_asserts.
2637  if (DS->isSingleDecl())
2638  return VisitDeclSubExpr(DS);
2639 
2640  CFGBlock *B = nullptr;
2641 
2642  // Build an individual DeclStmt for each decl.
2644  E = DS->decl_rend();
2645  I != E; ++I) {
2646 
2647  // Allocate the DeclStmt using the BumpPtrAllocator. It will get
2648  // automatically freed with the CFG.
2649  DeclGroupRef DG(*I);
2650  Decl *D = *I;
2651  DeclStmt *DSNew = new (Context) DeclStmt(DG, D->getLocation(), GetEndLoc(D));
2652  cfg->addSyntheticDeclStmt(DSNew, DS);
2653 
2654  // Append the fake DeclStmt to block.
2655  B = VisitDeclSubExpr(DSNew);
2656  }
2657 
2658  return B;
2659 }
2660 
2661 /// VisitDeclSubExpr - Utility method to add block-level expressions for
2662 /// DeclStmts and initializers in them.
2663 CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) {
2664  assert(DS->isSingleDecl() && "Can handle single declarations only.");
2665  VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl());
2666 
2667  if (!VD) {
2668  // Of everything that can be declared in a DeclStmt, only VarDecls impact
2669  // runtime semantics.
2670  return Block;
2671  }
2672 
2673  bool HasTemporaries = false;
2674 
2675  // Guard static initializers under a branch.
2676  CFGBlock *blockAfterStaticInit = nullptr;
2677 
2678  if (BuildOpts.AddStaticInitBranches && VD->isStaticLocal()) {
2679  // For static variables, we need to create a branch to track
2680  // whether or not they are initialized.
2681  if (Block) {
2682  Succ = Block;
2683  Block = nullptr;
2684  if (badCFG)
2685  return nullptr;
2686  }
2687  blockAfterStaticInit = Succ;
2688  }
2689 
2690  // Destructors of temporaries in initialization expression should be called
2691  // after initialization finishes.
2692  Expr *Init = VD->getInit();
2693  if (Init) {
2694  HasTemporaries = isa<ExprWithCleanups>(Init);
2695 
2696  if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
2697  // Generate destructors for temporaries in initialization expression.
2698  TempDtorContext Context;
2699  VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
2700  /*BindToTemporary=*/false, Context);
2701  }
2702  }
2703 
2704  autoCreateBlock();
2705  appendStmt(Block, DS);
2706 
2707  findConstructionContexts(
2708  ConstructionContextLayer::create(cfg->getBumpVectorContext(), DS),
2709  Init);
2710 
2711  // Keep track of the last non-null block, as 'Block' can be nulled out
2712  // if the initializer expression is something like a 'while' in a
2713  // statement-expression.
2714  CFGBlock *LastBlock = Block;
2715 
2716  if (Init) {
2717  if (HasTemporaries) {
2718  // For expression with temporaries go directly to subexpression to omit
2719  // generating destructors for the second time.
2720  ExprWithCleanups *EC = cast<ExprWithCleanups>(Init);
2721  if (CFGBlock *newBlock = Visit(EC->getSubExpr()))
2722  LastBlock = newBlock;
2723  }
2724  else {
2725  if (CFGBlock *newBlock = Visit(Init))
2726  LastBlock = newBlock;
2727  }
2728  }
2729 
2730  // If the type of VD is a VLA, then we must process its size expressions.
2731  for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr());
2732  VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr())) {
2733  if (CFGBlock *newBlock = addStmt(VA->getSizeExpr()))
2734  LastBlock = newBlock;
2735  }
2736 
2737  maybeAddScopeBeginForVarDecl(Block, VD, DS);
2738 
2739  // Remove variable from local scope.
2740  if (ScopePos && VD == *ScopePos)
2741  ++ScopePos;
2742 
2743  CFGBlock *B = LastBlock;
2744  if (blockAfterStaticInit) {
2745  Succ = B;
2746  Block = createBlock(false);
2747  Block->setTerminator(DS);
2748  addSuccessor(Block, blockAfterStaticInit);
2749  addSuccessor(Block, B);
2750  B = Block;
2751  }
2752 
2753  return B;
2754 }
2755 
2756 CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) {
2757  // We may see an if statement in the middle of a basic block, or it may be the
2758  // first statement we are processing. In either case, we create a new basic
2759  // block. First, we create the blocks for the then...else statements, and
2760  // then we create the block containing the if statement. If we were in the
2761  // middle of a block, we stop processing that block. That block is then the
2762  // implicit successor for the "then" and "else" clauses.
2763 
2764  // Save local scope position because in case of condition variable ScopePos
2765  // won't be restored when traversing AST.
2766  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2767 
2768  // Create local scope for C++17 if init-stmt if one exists.
2769  if (Stmt *Init = I->getInit())
2770  addLocalScopeForStmt(Init);
2771 
2772  // Create local scope for possible condition variable.
2773  // Store scope position. Add implicit destructor.
2774  if (VarDecl *VD = I->getConditionVariable())
2775  addLocalScopeForVarDecl(VD);
2776 
2777  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), I);
2778 
2779  // The block we were processing is now finished. Make it the successor
2780  // block.
2781  if (Block) {
2782  Succ = Block;
2783  if (badCFG)
2784  return nullptr;
2785  }
2786 
2787  // Process the false branch.
2788  CFGBlock *ElseBlock = Succ;
2789 
2790  if (Stmt *Else = I->getElse()) {
2791  SaveAndRestore<CFGBlock*> sv(Succ);
2792 
2793  // NULL out Block so that the recursive call to Visit will
2794  // create a new basic block.
2795  Block = nullptr;
2796 
2797  // If branch is not a compound statement create implicit scope
2798  // and add destructors.
2799  if (!isa<CompoundStmt>(Else))
2800  addLocalScopeAndDtors(Else);
2801 
2802  ElseBlock = addStmt(Else);
2803 
2804  if (!ElseBlock) // Can occur when the Else body has all NullStmts.
2805  ElseBlock = sv.get();
2806  else if (Block) {
2807  if (badCFG)
2808  return nullptr;
2809  }
2810  }
2811 
2812  // Process the true branch.
2813  CFGBlock *ThenBlock;
2814  {
2815  Stmt *Then = I->getThen();
2816  assert(Then);
2817  SaveAndRestore<CFGBlock*> sv(Succ);
2818  Block = nullptr;
2819 
2820  // If branch is not a compound statement create implicit scope
2821  // and add destructors.
2822  if (!isa<CompoundStmt>(Then))
2823  addLocalScopeAndDtors(Then);
2824 
2825  ThenBlock = addStmt(Then);
2826 
2827  if (!ThenBlock) {
2828  // We can reach here if the "then" body has all NullStmts.
2829  // Create an empty block so we can distinguish between true and false
2830  // branches in path-sensitive analyses.
2831  ThenBlock = createBlock(false);
2832  addSuccessor(ThenBlock, sv.get());
2833  } else if (Block) {
2834  if (badCFG)
2835  return nullptr;
2836  }
2837  }
2838 
2839  // Specially handle "if (expr1 || ...)" and "if (expr1 && ...)" by
2840  // having these handle the actual control-flow jump. Note that
2841  // if we introduce a condition variable, e.g. "if (int x = exp1 || exp2)"
2842  // we resort to the old control-flow behavior. This special handling
2843  // removes infeasible paths from the control-flow graph by having the
2844  // control-flow transfer of '&&' or '||' go directly into the then/else
2845  // blocks directly.
2846  BinaryOperator *Cond =
2848  ? nullptr
2849  : dyn_cast<BinaryOperator>(I->getCond()->IgnoreParens());
2850  CFGBlock *LastBlock;
2851  if (Cond && Cond->isLogicalOp())
2852  LastBlock = VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first;
2853  else {
2854  // Now create a new block containing the if statement.
2855  Block = createBlock(false);
2856 
2857  // Set the terminator of the new block to the If statement.
2858  Block->setTerminator(I);
2859 
2860  // See if this is a known constant.
2861  const TryResult &KnownVal = tryEvaluateBool(I->getCond());
2862 
2863  // Add the successors. If we know that specific branches are
2864  // unreachable, inform addSuccessor() of that knowledge.
2865  addSuccessor(Block, ThenBlock, /* isReachable = */ !KnownVal.isFalse());
2866  addSuccessor(Block, ElseBlock, /* isReachable = */ !KnownVal.isTrue());
2867 
2868  // Add the condition as the last statement in the new block. This may
2869  // create new blocks as the condition may contain control-flow. Any newly
2870  // created blocks will be pointed to be "Block".
2871  LastBlock = addStmt(I->getCond());
2872 
2873  // If the IfStmt contains a condition variable, add it and its
2874  // initializer to the CFG.
2875  if (const DeclStmt* DS = I->getConditionVariableDeclStmt()) {
2876  autoCreateBlock();
2877  LastBlock = addStmt(const_cast<DeclStmt *>(DS));
2878  }
2879  }
2880 
2881  // Finally, if the IfStmt contains a C++17 init-stmt, add it to the CFG.
2882  if (Stmt *Init = I->getInit()) {
2883  autoCreateBlock();
2884  LastBlock = addStmt(Init);
2885  }
2886 
2887  return LastBlock;
2888 }
2889 
2890 CFGBlock *CFGBuilder::VisitReturnStmt(Stmt *S) {
2891  // If we were in the middle of a block we stop processing that block.
2892  //
2893  // NOTE: If a "return" or "co_return" appears in the middle of a block, this
2894  // means that the code afterwards is DEAD (unreachable). We still keep
2895  // a basic block for that code; a simple "mark-and-sweep" from the entry
2896  // block will be able to report such dead blocks.
2897  assert(isa<ReturnStmt>(S) || isa<CoreturnStmt>(S));
2898 
2899  // Create the new block.
2900  Block = createBlock(false);
2901 
2902  addAutomaticObjHandling(ScopePos, LocalScope::const_iterator(), S);
2903 
2904  if (auto *R = dyn_cast<ReturnStmt>(S))
2905  findConstructionContexts(
2906  ConstructionContextLayer::create(cfg->getBumpVectorContext(), R),
2907  R->getRetValue());
2908 
2909  // If the one of the destructors does not return, we already have the Exit
2910  // block as a successor.
2911  if (!Block->hasNoReturnElement())
2912  addSuccessor(Block, &cfg->getExit());
2913 
2914  // Add the return statement to the block. This may create new blocks if R
2915  // contains control-flow (short-circuit operations).
2916  return VisitStmt(S, AddStmtChoice::AlwaysAdd);
2917 }
2918 
2919 CFGBlock *CFGBuilder::VisitSEHExceptStmt(SEHExceptStmt *ES) {
2920  // SEHExceptStmt are treated like labels, so they are the first statement in a
2921  // block.
2922 
2923  // Save local scope position because in case of exception variable ScopePos
2924  // won't be restored when traversing AST.
2925  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2926 
2927  addStmt(ES->getBlock());
2928  CFGBlock *SEHExceptBlock = Block;
2929  if (!SEHExceptBlock)
2930  SEHExceptBlock = createBlock();
2931 
2932  appendStmt(SEHExceptBlock, ES);
2933 
2934  // Also add the SEHExceptBlock as a label, like with regular labels.
2935  SEHExceptBlock->setLabel(ES);
2936 
2937  // Bail out if the CFG is bad.
2938  if (badCFG)
2939  return nullptr;
2940 
2941  // We set Block to NULL to allow lazy creation of a new block (if necessary).
2942  Block = nullptr;
2943 
2944  return SEHExceptBlock;
2945 }
2946 
2947 CFGBlock *CFGBuilder::VisitSEHFinallyStmt(SEHFinallyStmt *FS) {
2948  return VisitCompoundStmt(FS->getBlock());
2949 }
2950 
2951 CFGBlock *CFGBuilder::VisitSEHLeaveStmt(SEHLeaveStmt *LS) {
2952  // "__leave" is a control-flow statement. Thus we stop processing the current
2953  // block.
2954  if (badCFG)
2955  return nullptr;
2956 
2957  // Now create a new block that ends with the __leave statement.
2958  Block = createBlock(false);
2959  Block->setTerminator(LS);
2960 
2961  // If there is no target for the __leave, then we are looking at an incomplete
2962  // AST. This means that the CFG cannot be constructed.
2963  if (SEHLeaveJumpTarget.block) {
2964  addAutomaticObjHandling(ScopePos, SEHLeaveJumpTarget.scopePosition, LS);
2965  addSuccessor(Block, SEHLeaveJumpTarget.block);
2966  } else
2967  badCFG = true;
2968 
2969  return Block;
2970 }
2971 
2972 CFGBlock *CFGBuilder::VisitSEHTryStmt(SEHTryStmt *Terminator) {
2973  // "__try"/"__except"/"__finally" is a control-flow statement. Thus we stop
2974  // processing the current block.
2975  CFGBlock *SEHTrySuccessor = nullptr;
2976 
2977  if (Block) {
2978  if (badCFG)
2979  return nullptr;
2980  SEHTrySuccessor = Block;
2981  } else SEHTrySuccessor = Succ;
2982 
2983  // FIXME: Implement __finally support.
2984  if (Terminator->getFinallyHandler())
2985  return NYS();
2986 
2987  CFGBlock *PrevSEHTryTerminatedBlock = TryTerminatedBlock;
2988 
2989  // Create a new block that will contain the __try statement.
2990  CFGBlock *NewTryTerminatedBlock = createBlock(false);
2991 
2992  // Add the terminator in the __try block.
2993  NewTryTerminatedBlock->setTerminator(Terminator);
2994 
2995  if (SEHExceptStmt *Except = Terminator->getExceptHandler()) {
2996  // The code after the try is the implicit successor if there's an __except.
2997  Succ = SEHTrySuccessor;
2998  Block = nullptr;
2999  CFGBlock *ExceptBlock = VisitSEHExceptStmt(Except);
3000  if (!ExceptBlock)
3001  return nullptr;
3002  // Add this block to the list of successors for the block with the try
3003  // statement.
3004  addSuccessor(NewTryTerminatedBlock, ExceptBlock);
3005  }
3006  if (PrevSEHTryTerminatedBlock)
3007  addSuccessor(NewTryTerminatedBlock, PrevSEHTryTerminatedBlock);
3008  else
3009  addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
3010 
3011  // The code after the try is the implicit successor.
3012  Succ = SEHTrySuccessor;
3013 
3014  // Save the current "__try" context.
3015  SaveAndRestore<CFGBlock *> save_try(TryTerminatedBlock,
3016  NewTryTerminatedBlock);
3017  cfg->addTryDispatchBlock(TryTerminatedBlock);
3018 
3019  // Save the current value for the __leave target.
3020  // All __leaves should go to the code following the __try
3021  // (FIXME: or if the __try has a __finally, to the __finally.)
3022  SaveAndRestore<JumpTarget> save_break(SEHLeaveJumpTarget);
3023  SEHLeaveJumpTarget = JumpTarget(SEHTrySuccessor, ScopePos);
3024 
3025  assert(Terminator->getTryBlock() && "__try must contain a non-NULL body");
3026  Block = nullptr;
3027  return addStmt(Terminator->getTryBlock());
3028 }
3029 
3030 CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) {
3031  // Get the block of the labeled statement. Add it to our map.
3032  addStmt(L->getSubStmt());
3033  CFGBlock *LabelBlock = Block;
3034 
3035  if (!LabelBlock) // This can happen when the body is empty, i.e.
3036  LabelBlock = createBlock(); // scopes that only contains NullStmts.
3037 
3038  assert(LabelMap.find(L->getDecl()) == LabelMap.end() &&
3039  "label already in map");
3040  LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos);
3041 
3042  // Labels partition blocks, so this is the end of the basic block we were
3043  // processing (L is the block's label). Because this is label (and we have
3044  // already processed the substatement) there is no extra control-flow to worry
3045  // about.
3046  LabelBlock->setLabel(L);
3047  if (badCFG)
3048  return nullptr;
3049 
3050  // We set Block to NULL to allow lazy creation of a new block (if necessary);
3051  Block = nullptr;
3052 
3053  // This block is now the implicit successor of other blocks.
3054  Succ = LabelBlock;
3055 
3056  return LabelBlock;
3057 }
3058 
3059 CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) {
3060  CFGBlock *LastBlock = VisitNoRecurse(E, asc);
3061  for (const BlockDecl::Capture &CI : E->getBlockDecl()->captures()) {
3062  if (Expr *CopyExpr = CI.getCopyExpr()) {
3063  CFGBlock *Tmp = Visit(CopyExpr);
3064  if (Tmp)
3065  LastBlock = Tmp;
3066  }
3067  }
3068  return LastBlock;
3069 }
3070 
3071 CFGBlock *CFGBuilder::VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc) {
3072  CFGBlock *LastBlock = VisitNoRecurse(E, asc);
3074  et = E->capture_init_end(); it != et; ++it) {
3075  if (Expr *Init = *it) {
3076  CFGBlock *Tmp = Visit(Init);
3077  if (Tmp)
3078  LastBlock = Tmp;
3079  }
3080  }
3081  return LastBlock;
3082 }
3083 
3084 CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) {
3085  // Goto is a control-flow statement. Thus we stop processing the current
3086  // block and create a new one.
3087 
3088  Block = createBlock(false);
3089  Block->setTerminator(G);
3090 
3091  // If we already know the mapping to the label block add the successor now.
3092  LabelMapTy::iterator I = LabelMap.find(G->getLabel());
3093 
3094  if (I == LabelMap.end())
3095  // We will need to backpatch this block later.
3096  BackpatchBlocks.push_back(JumpSource(Block, ScopePos));
3097  else {
3098  JumpTarget JT = I->second;
3099  addAutomaticObjHandling(ScopePos, JT.scopePosition, G);
3100  addSuccessor(Block, JT.block);
3101  }
3102 
3103  return Block;
3104 }
3105 
3106 CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) {
3107  CFGBlock *LoopSuccessor = nullptr;
3108 
3109  // Save local scope position because in case of condition variable ScopePos
3110  // won't be restored when traversing AST.
3111  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3112 
3113  // Create local scope for init statement and possible condition variable.
3114  // Add destructor for init statement and condition variable.
3115  // Store scope position for continue statement.
3116  if (Stmt *Init = F->getInit())
3117  addLocalScopeForStmt(Init);
3118  LocalScope::const_iterator LoopBeginScopePos = ScopePos;
3119 
3120  if (VarDecl *VD = F->getConditionVariable())
3121  addLocalScopeForVarDecl(VD);
3122  LocalScope::const_iterator ContinueScopePos = ScopePos;
3123 
3124  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), F);
3125 
3126  addLoopExit(F);
3127 
3128  // "for" is a control-flow statement. Thus we stop processing the current
3129  // block.
3130  if (Block) {
3131  if (badCFG)
3132  return nullptr;
3133  LoopSuccessor = Block;
3134  } else
3135  LoopSuccessor = Succ;
3136 
3137  // Save the current value for the break targets.
3138  // All breaks should go to the code following the loop.
3139  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3140  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3141 
3142  CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
3143 
3144  // Now create the loop body.
3145  {
3146  assert(F->getBody());
3147 
3148  // Save the current values for Block, Succ, continue and break targets.
3149  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3150  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
3151 
3152  // Create an empty block to represent the transition block for looping back
3153  // to the head of the loop. If we have increment code, it will
3154  // go in this block as well.
3155  Block = Succ = TransitionBlock = createBlock(false);
3156  TransitionBlock->setLoopTarget(F);
3157 
3158  if (Stmt *I = F->getInc()) {
3159  // Generate increment code in its own basic block. This is the target of
3160  // continue statements.
3161  Succ = addStmt(I);
3162  }
3163 
3164  // Finish up the increment (or empty) block if it hasn't been already.
3165  if (Block) {
3166  assert(Block == Succ);
3167  if (badCFG)
3168  return nullptr;
3169  Block = nullptr;
3170  }
3171 
3172  // The starting block for the loop increment is the block that should
3173  // represent the 'loop target' for looping back to the start of the loop.
3174  ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
3175  ContinueJumpTarget.block->setLoopTarget(F);
3176 
3177  // Loop body should end with destructor of Condition variable (if any).
3178  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, F);
3179 
3180  // If body is not a compound statement create implicit scope
3181  // and add destructors.
3182  if (!isa<CompoundStmt>(F->getBody()))
3183  addLocalScopeAndDtors(F->getBody());
3184 
3185  // Now populate the body block, and in the process create new blocks as we
3186  // walk the body of the loop.
3187  BodyBlock = addStmt(F->getBody());
3188 
3189  if (!BodyBlock) {
3190  // In the case of "for (...;...;...);" we can have a null BodyBlock.
3191  // Use the continue jump target as the proxy for the body.
3192  BodyBlock = ContinueJumpTarget.block;
3193  }
3194  else if (badCFG)
3195  return nullptr;
3196  }
3197 
3198  // Because of short-circuit evaluation, the condition of the loop can span
3199  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3200  // evaluate the condition.
3201  CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
3202 
3203  do {
3204  Expr *C = F->getCond();
3205  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3206 
3207  // Specially handle logical operators, which have a slightly
3208  // more optimal CFG representation.
3209  if (BinaryOperator *Cond =
3210  dyn_cast_or_null<BinaryOperator>(C ? C->IgnoreParens() : nullptr))
3211  if (Cond->isLogicalOp()) {
3212  std::tie(EntryConditionBlock, ExitConditionBlock) =
3213  VisitLogicalOperator(Cond, F, BodyBlock, LoopSuccessor);
3214  break;
3215  }
3216 
3217  // The default case when not handling logical operators.
3218  EntryConditionBlock = ExitConditionBlock = createBlock(false);
3219  ExitConditionBlock->setTerminator(F);
3220 
3221  // See if this is a known constant.
3222  TryResult KnownVal(true);
3223 
3224  if (C) {
3225  // Now add the actual condition to the condition block.
3226  // Because the condition itself may contain control-flow, new blocks may
3227  // be created. Thus we update "Succ" after adding the condition.
3228  Block = ExitConditionBlock;
3229  EntryConditionBlock = addStmt(C);
3230 
3231  // If this block contains a condition variable, add both the condition
3232  // variable and initializer to the CFG.
3233  if (VarDecl *VD = F->getConditionVariable()) {
3234  if (Expr *Init = VD->getInit()) {
3235  autoCreateBlock();
3236  const DeclStmt *DS = F->getConditionVariableDeclStmt();
3237  assert(DS->isSingleDecl());
3238  findConstructionContexts(
3239  ConstructionContextLayer::create(cfg->getBumpVectorContext(), DS),
3240  Init);
3241  appendStmt(Block, DS);
3242  EntryConditionBlock = addStmt(Init);
3243  assert(Block == EntryConditionBlock);
3244  maybeAddScopeBeginForVarDecl(EntryConditionBlock, VD, C);
3245  }
3246  }
3247 
3248  if (Block && badCFG)
3249  return nullptr;
3250 
3251  KnownVal = tryEvaluateBool(C);
3252  }
3253 
3254  // Add the loop body entry as a successor to the condition.
3255  addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
3256  // Link up the condition block with the code that follows the loop. (the
3257  // false branch).
3258  addSuccessor(ExitConditionBlock,
3259  KnownVal.isTrue() ? nullptr : LoopSuccessor);
3260  } while (false);
3261 
3262  // Link up the loop-back block to the entry condition block.
3263  addSuccessor(TransitionBlock, EntryConditionBlock);
3264 
3265  // The condition block is the implicit successor for any code above the loop.
3266  Succ = EntryConditionBlock;
3267 
3268  // If the loop contains initialization, create a new block for those
3269  // statements. This block can also contain statements that precede the loop.
3270  if (Stmt *I = F->getInit()) {
3271  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3272  ScopePos = LoopBeginScopePos;
3273  Block = createBlock();
3274  return addStmt(I);
3275  }
3276 
3277  // There is no loop initialization. We are thus basically a while loop.
3278  // NULL out Block to force lazy block construction.
3279  Block = nullptr;
3280  Succ = EntryConditionBlock;
3281  return EntryConditionBlock;
3282 }
3283 
3284 CFGBlock *
3285 CFGBuilder::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *MTE,
3286  AddStmtChoice asc) {
3287  findConstructionContexts(
3288  ConstructionContextLayer::create(cfg->getBumpVectorContext(), MTE),
3289  MTE->getTemporary());
3290 
3291  return VisitStmt(MTE, asc);
3292 }
3293 
3294 CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) {
3295  if (asc.alwaysAdd(*this, M)) {
3296  autoCreateBlock();
3297  appendStmt(Block, M);
3298  }
3299  return Visit(M->getBase());
3300 }
3301 
3302 CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) {
3303  // Objective-C fast enumeration 'for' statements:
3304  // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC
3305  //
3306  // for ( Type newVariable in collection_expression ) { statements }
3307  //
3308  // becomes:
3309  //
3310  // prologue:
3311  // 1. collection_expression
3312  // T. jump to loop_entry
3313  // loop_entry:
3314  // 1. side-effects of element expression
3315  // 1. ObjCForCollectionStmt [performs binding to newVariable]
3316  // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil]
3317  // TB:
3318  // statements
3319  // T. jump to loop_entry
3320  // FB:
3321  // what comes after
3322  //
3323  // and
3324  //
3325  // Type existingItem;
3326  // for ( existingItem in expression ) { statements }
3327  //
3328  // becomes:
3329  //
3330  // the same with newVariable replaced with existingItem; the binding works
3331  // the same except that for one ObjCForCollectionStmt::getElement() returns
3332  // a DeclStmt and the other returns a DeclRefExpr.
3333 
3334  CFGBlock *LoopSuccessor = nullptr;
3335 
3336  if (Block) {
3337  if (badCFG)
3338  return nullptr;
3339  LoopSuccessor = Block;
3340  Block = nullptr;
3341  } else
3342  LoopSuccessor = Succ;
3343 
3344  // Build the condition blocks.
3345  CFGBlock *ExitConditionBlock = createBlock(false);
3346 
3347  // Set the terminator for the "exit" condition block.
3348  ExitConditionBlock->setTerminator(S);
3349 
3350  // The last statement in the block should be the ObjCForCollectionStmt, which
3351  // performs the actual binding to 'element' and determines if there are any
3352  // more items in the collection.
3353  appendStmt(ExitConditionBlock, S);
3354  Block = ExitConditionBlock;
3355 
3356  // Walk the 'element' expression to see if there are any side-effects. We
3357  // generate new blocks as necessary. We DON'T add the statement by default to
3358  // the CFG unless it contains control-flow.
3359  CFGBlock *EntryConditionBlock = Visit(S->getElement(),
3360  AddStmtChoice::NotAlwaysAdd);
3361  if (Block) {
3362  if (badCFG)
3363  return nullptr;
3364  Block = nullptr;
3365  }
3366 
3367  // The condition block is the implicit successor for the loop body as well as
3368  // any code above the loop.
3369  Succ = EntryConditionBlock;
3370 
3371  // Now create the true branch.
3372  {
3373  // Save the current values for Succ, continue and break targets.
3374  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3375  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3376  save_break(BreakJumpTarget);
3377 
3378  // Add an intermediate block between the BodyBlock and the
3379  // EntryConditionBlock to represent the "loop back" transition, for looping
3380  // back to the head of the loop.
3381  CFGBlock *LoopBackBlock = nullptr;
3382  Succ = LoopBackBlock = createBlock();
3383  LoopBackBlock->setLoopTarget(S);
3384 
3385  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3386  ContinueJumpTarget = JumpTarget(Succ, ScopePos);
3387 
3388  CFGBlock *BodyBlock = addStmt(S->getBody());
3389 
3390  if (!BodyBlock)
3391  BodyBlock = ContinueJumpTarget.block; // can happen for "for (X in Y) ;"
3392  else if (Block) {
3393  if (badCFG)
3394  return nullptr;
3395  }
3396 
3397  // This new body block is a successor to our "exit" condition block.
3398  addSuccessor(ExitConditionBlock, BodyBlock);
3399  }
3400 
3401  // Link up the condition block with the code that follows the loop.
3402  // (the false branch).
3403  addSuccessor(ExitConditionBlock, LoopSuccessor);
3404 
3405  // Now create a prologue block to contain the collection expression.
3406  Block = createBlock();
3407  return addStmt(S->getCollection());
3408 }
3409 
3410 CFGBlock *CFGBuilder::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) {
3411  // Inline the body.
3412  return addStmt(S->getSubStmt());
3413  // TODO: consider adding cleanups for the end of @autoreleasepool scope.
3414 }
3415 
3416 CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) {
3417  // FIXME: Add locking 'primitives' to CFG for @synchronized.
3418 
3419  // Inline the body.
3420  CFGBlock *SyncBlock = addStmt(S->getSynchBody());
3421 
3422  // The sync body starts its own basic block. This makes it a little easier
3423  // for diagnostic clients.
3424  if (SyncBlock) {
3425  if (badCFG)
3426  return nullptr;
3427 
3428  Block = nullptr;
3429  Succ = SyncBlock;
3430  }
3431 
3432  // Add the @synchronized to the CFG.
3433  autoCreateBlock();
3434  appendStmt(Block, S);
3435 
3436  // Inline the sync expression.
3437  return addStmt(S->getSynchExpr());
3438 }
3439 
3440 CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) {
3441  // FIXME
3442  return NYS();
3443 }
3444 
3445 CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) {
3446  autoCreateBlock();
3447 
3448  // Add the PseudoObject as the last thing.
3449  appendStmt(Block, E);
3450 
3451  CFGBlock *lastBlock = Block;
3452 
3453  // Before that, evaluate all of the semantics in order. In
3454  // CFG-land, that means appending them in reverse order.
3455  for (unsigned i = E->getNumSemanticExprs(); i != 0; ) {
3456  Expr *Semantic = E->getSemanticExpr(--i);
3457 
3458  // If the semantic is an opaque value, we're being asked to bind
3459  // it to its source expression.
3460  if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
3461  Semantic = OVE->getSourceExpr();
3462 
3463  if (CFGBlock *B = Visit(Semantic))
3464  lastBlock = B;
3465  }
3466 
3467  return lastBlock;
3468 }
3469 
3470 CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) {
3471  CFGBlock *LoopSuccessor = nullptr;
3472 
3473  // Save local scope position because in case of condition variable ScopePos
3474  // won't be restored when traversing AST.
3475  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3476 
3477  // Create local scope for possible condition variable.
3478  // Store scope position for continue statement.
3479  LocalScope::const_iterator LoopBeginScopePos = ScopePos;
3480  if (VarDecl *VD = W->getConditionVariable()) {
3481  addLocalScopeForVarDecl(VD);
3482  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3483  }
3484  addLoopExit(W);
3485 
3486  // "while" is a control-flow statement. Thus we stop processing the current
3487  // block.
3488  if (Block) {
3489  if (badCFG)
3490  return nullptr;
3491  LoopSuccessor = Block;
3492  Block = nullptr;
3493  } else {
3494  LoopSuccessor = Succ;
3495  }
3496 
3497  CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
3498 
3499  // Process the loop body.
3500  {
3501  assert(W->getBody());
3502 
3503  // Save the current values for Block, Succ, continue and break targets.
3504  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3505  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3506  save_break(BreakJumpTarget);
3507 
3508  // Create an empty block to represent the transition block for looping back
3509  // to the head of the loop.
3510  Succ = TransitionBlock = createBlock(false);
3511  TransitionBlock->setLoopTarget(W);
3512  ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos);
3513 
3514  // All breaks should go to the code following the loop.
3515  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3516 
3517  // Loop body should end with destructor of Condition variable (if any).
3518  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3519 
3520  // If body is not a compound statement create implicit scope
3521  // and add destructors.
3522  if (!isa<CompoundStmt>(W->getBody()))
3523  addLocalScopeAndDtors(W->getBody());
3524 
3525  // Create the body. The returned block is the entry to the loop body.
3526  BodyBlock = addStmt(W->getBody());
3527 
3528  if (!BodyBlock)
3529  BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;"
3530  else if (Block && badCFG)
3531  return nullptr;
3532  }
3533 
3534  // Because of short-circuit evaluation, the condition of the loop can span
3535  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3536  // evaluate the condition.
3537  CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
3538 
3539  do {
3540  Expr *C = W->getCond();
3541 
3542  // Specially handle logical operators, which have a slightly
3543  // more optimal CFG representation.
3544  if (BinaryOperator *Cond = dyn_cast<BinaryOperator>(C->IgnoreParens()))
3545  if (Cond->isLogicalOp()) {
3546  std::tie(EntryConditionBlock, ExitConditionBlock) =
3547  VisitLogicalOperator(Cond, W, BodyBlock, LoopSuccessor);
3548  break;
3549  }
3550 
3551  // The default case when not handling logical operators.
3552  ExitConditionBlock = createBlock(false);
3553  ExitConditionBlock->setTerminator(W);
3554 
3555  // Now add the actual condition to the condition block.
3556  // Because the condition itself may contain control-flow, new blocks may
3557  // be created. Thus we update "Succ" after adding the condition.
3558  Block = ExitConditionBlock;
3559  Block = EntryConditionBlock = addStmt(C);
3560 
3561  // If this block contains a condition variable, add both the condition
3562  // variable and initializer to the CFG.
3563  if (VarDecl *VD = W->getConditionVariable()) {
3564  if (Expr *Init = VD->getInit()) {
3565  autoCreateBlock();
3566  const DeclStmt *DS = W->getConditionVariableDeclStmt();
3567  assert(DS->isSingleDecl());
3568  findConstructionContexts(
3569  ConstructionContextLayer::create(cfg->getBumpVectorContext(),
3570  const_cast<DeclStmt *>(DS)),
3571  Init);
3572  appendStmt(Block, DS);
3573  EntryConditionBlock = addStmt(Init);
3574  assert(Block == EntryConditionBlock);
3575  maybeAddScopeBeginForVarDecl(EntryConditionBlock, VD, C);
3576  }
3577  }
3578 
3579  if (Block && badCFG)
3580  return nullptr;
3581 
3582  // See if this is a known constant.
3583  const TryResult& KnownVal = tryEvaluateBool(C);
3584 
3585  // Add the loop body entry as a successor to the condition.
3586  addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
3587  // Link up the condition block with the code that follows the loop. (the
3588  // false branch).
3589  addSuccessor(ExitConditionBlock,
3590  KnownVal.isTrue() ? nullptr : LoopSuccessor);
3591  } while(false);
3592 
3593  // Link up the loop-back block to the entry condition block.
3594  addSuccessor(TransitionBlock, EntryConditionBlock);
3595 
3596  // There can be no more statements in the condition block since we loop back
3597  // to this block. NULL out Block to force lazy creation of another block.
3598  Block = nullptr;
3599 
3600  // Return the condition block, which is the dominating block for the loop.
3601  Succ = EntryConditionBlock;
3602  return EntryConditionBlock;
3603 }
3604 
3605 CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) {
3606  // FIXME: For now we pretend that @catch and the code it contains does not
3607  // exit.
3608  return Block;
3609 }
3610 
3611 CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) {
3612  // FIXME: This isn't complete. We basically treat @throw like a return
3613  // statement.
3614 
3615  // If we were in the middle of a block we stop processing that block.
3616  if (badCFG)
3617  return nullptr;
3618 
3619  // Create the new block.
3620  Block = createBlock(false);
3621 
3622  // The Exit block is the only successor.
3623  addSuccessor(Block, &cfg->getExit());
3624 
3625  // Add the statement to the block. This may create new blocks if S contains
3626  // control-flow (short-circuit operations).
3627  return VisitStmt(S, AddStmtChoice::AlwaysAdd);
3628 }
3629 
3630 CFGBlock *CFGBuilder::VisitObjCMessageExpr(ObjCMessageExpr *ME,
3631  AddStmtChoice asc) {
3632  findConstructionContextsForArguments(ME);
3633 
3634  autoCreateBlock();
3635  appendObjCMessage(Block, ME);
3636 
3637  return VisitChildren(ME);
3638 }
3639 
3640 CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) {
3641  // If we were in the middle of a block we stop processing that block.
3642  if (badCFG)
3643  return nullptr;
3644 
3645  // Create the new block.
3646  Block = createBlock(false);
3647 
3648  if (TryTerminatedBlock)
3649  // The current try statement is the only successor.
3650  addSuccessor(Block, TryTerminatedBlock);
3651  else
3652  // otherwise the Exit block is the only successor.
3653  addSuccessor(Block, &cfg->getExit());
3654 
3655  // Add the statement to the block. This may create new blocks if S contains
3656  // control-flow (short-circuit operations).
3657  return VisitStmt(T, AddStmtChoice::AlwaysAdd);
3658 }
3659 
3660 CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) {
3661  CFGBlock *LoopSuccessor = nullptr;
3662 
3663  addLoopExit(D);
3664 
3665  // "do...while" is a control-flow statement. Thus we stop processing the
3666  // current block.
3667  if (Block) {
3668  if (badCFG)
3669  return nullptr;
3670  LoopSuccessor = Block;
3671  } else
3672  LoopSuccessor = Succ;
3673 
3674  // Because of short-circuit evaluation, the condition of the loop can span
3675  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3676  // evaluate the condition.
3677  CFGBlock *ExitConditionBlock = createBlock(false);
3678  CFGBlock *EntryConditionBlock = ExitConditionBlock;
3679 
3680  // Set the terminator for the "exit" condition block.
3681  ExitConditionBlock->setTerminator(D);
3682 
3683  // Now add the actual condition to the condition block. Because the condition
3684  // itself may contain control-flow, new blocks may be created.
3685  if (Stmt *C = D->getCond()) {
3686  Block = ExitConditionBlock;
3687  EntryConditionBlock = addStmt(C);
3688  if (Block) {
3689  if (badCFG)
3690  return nullptr;
3691  }
3692  }
3693 
3694  // The condition block is the implicit successor for the loop body.
3695  Succ = EntryConditionBlock;
3696 
3697  // See if this is a known constant.
3698  const TryResult &KnownVal = tryEvaluateBool(D->getCond());
3699 
3700  // Process the loop body.
3701  CFGBlock *BodyBlock = nullptr;
3702  {
3703  assert(D->getBody());
3704 
3705  // Save the current values for Block, Succ, and continue and break targets
3706  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3707  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3708  save_break(BreakJumpTarget);
3709 
3710  // All continues within this loop should go to the condition block
3711  ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos);
3712 
3713  // All breaks should go to the code following the loop.
3714  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3715 
3716  // NULL out Block to force lazy instantiation of blocks for the body.
3717  Block = nullptr;
3718 
3719  // If body is not a compound statement create implicit scope
3720  // and add destructors.
3721  if (!isa<CompoundStmt>(D->getBody()))
3722  addLocalScopeAndDtors(D->getBody());
3723 
3724  // Create the body. The returned block is the entry to the loop body.
3725  BodyBlock = addStmt(D->getBody());
3726 
3727  if (!BodyBlock)
3728  BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)"
3729  else if (Block) {
3730  if (badCFG)
3731  return nullptr;
3732  }
3733 
3734  // Add an intermediate block between the BodyBlock and the
3735  // ExitConditionBlock to represent the "loop back" transition. Create an
3736  // empty block to represent the transition block for looping back to the
3737  // head of the loop.
3738  // FIXME: Can we do this more efficiently without adding another block?
3739  Block = nullptr;
3740  Succ = BodyBlock;
3741  CFGBlock *LoopBackBlock = createBlock();
3742  LoopBackBlock->setLoopTarget(D);
3743 
3744  if (!KnownVal.isFalse())
3745  // Add the loop body entry as a successor to the condition.
3746  addSuccessor(ExitConditionBlock, LoopBackBlock);
3747  else
3748  addSuccessor(ExitConditionBlock, nullptr);
3749  }
3750 
3751  // Link up the condition block with the code that follows the loop.
3752  // (the false branch).
3753  addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
3754 
3755  // There can be no more statements in the body block(s) since we loop back to
3756  // the body. NULL out Block to force lazy creation of another block.
3757  Block = nullptr;
3758 
3759  // Return the loop body, which is the dominating block for the loop.
3760  Succ = BodyBlock;
3761  return BodyBlock;
3762 }
3763 
3764 CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) {
3765  // "continue" is a control-flow statement. Thus we stop processing the
3766  // current block.
3767  if (badCFG)
3768  return nullptr;
3769 
3770  // Now create a new block that ends with the continue statement.
3771  Block = createBlock(false);
3772  Block->setTerminator(C);
3773 
3774  // If there is no target for the continue, then we are looking at an
3775  // incomplete AST. This means the CFG cannot be constructed.
3776  if (ContinueJumpTarget.block) {
3777  addAutomaticObjHandling(ScopePos, ContinueJumpTarget.scopePosition, C);
3778  addSuccessor(Block, ContinueJumpTarget.block);
3779  } else
3780  badCFG = true;
3781 
3782  return Block;
3783 }
3784 
3785 CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
3786  AddStmtChoice asc) {
3787  if (asc.alwaysAdd(*this, E)) {
3788  autoCreateBlock();
3789  appendStmt(Block, E);
3790  }
3791 
3792  // VLA types have expressions that must be evaluated.
3793  CFGBlock *lastBlock = Block;
3794 
3795  if (E->isArgumentType()) {
3796  for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr());
3797  VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr()))
3798  lastBlock = addStmt(VA->getSizeExpr());
3799  }
3800  return lastBlock;
3801 }
3802 
3803 /// VisitStmtExpr - Utility method to handle (nested) statement
3804 /// expressions (a GCC extension).
3805 CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) {
3806  if (asc.alwaysAdd(*this, SE)) {
3807  autoCreateBlock();
3808  appendStmt(Block, SE);
3809  }
3810  return VisitCompoundStmt(SE->getSubStmt());
3811 }
3812 
3813 CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) {
3814  // "switch" is a control-flow statement. Thus we stop processing the current
3815  // block.
3816  CFGBlock *SwitchSuccessor = nullptr;
3817 
3818  // Save local scope position because in case of condition variable ScopePos
3819  // won't be restored when traversing AST.
3820  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3821 
3822  // Create local scope for C++17 switch init-stmt if one exists.
3823  if (Stmt *Init = Terminator->getInit())
3824  addLocalScopeForStmt(Init);
3825 
3826  // Create local scope for possible condition variable.
3827  // Store scope position. Add implicit destructor.
3828  if (VarDecl *VD = Terminator->getConditionVariable())
3829  addLocalScopeForVarDecl(VD);
3830 
3831  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), Terminator);
3832 
3833  if (Block) {
3834  if (badCFG)
3835  return nullptr;
3836  SwitchSuccessor = Block;
3837  } else SwitchSuccessor = Succ;
3838 
3839  // Save the current "switch" context.
3840  SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock),
3841  save_default(DefaultCaseBlock);
3842  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3843 
3844  // Set the "default" case to be the block after the switch statement. If the
3845  // switch statement contains a "default:", this value will be overwritten with
3846  // the block for that code.
3847  DefaultCaseBlock = SwitchSuccessor;
3848 
3849  // Create a new block that will contain the switch statement.
3850  SwitchTerminatedBlock = createBlock(false);
3851 
3852  // Now process the switch body. The code after the switch is the implicit
3853  // successor.
3854  Succ = SwitchSuccessor;
3855  BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos);
3856 
3857  // When visiting the body, the case statements should automatically get linked
3858  // up to the switch. We also don't keep a pointer to the body, since all
3859  // control-flow from the switch goes to case/default statements.
3860  assert(Terminator->getBody() && "switch must contain a non-NULL body");
3861  Block = nullptr;
3862 
3863  // For pruning unreachable case statements, save the current state
3864  // for tracking the condition value.
3865  SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered,
3866  false);
3867 
3868  // Determine if the switch condition can be explicitly evaluated.
3869  assert(Terminator->getCond() && "switch condition must be non-NULL");
3870  Expr::EvalResult result;
3871  bool b = tryEvaluate(Terminator->getCond(), result);
3872  SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond,
3873  b ? &result : nullptr);
3874 
3875  // If body is not a compound statement create implicit scope
3876  // and add destructors.
3877  if (!isa<CompoundStmt>(Terminator->getBody()))
3878  addLocalScopeAndDtors(Terminator->getBody());
3879 
3880  addStmt(Terminator->getBody());
3881  if (Block) {
3882  if (badCFG)
3883  return nullptr;
3884  }
3885 
3886  // If we have no "default:" case, the default transition is to the code
3887  // following the switch body. Moreover, take into account if all the
3888  // cases of a switch are covered (e.g., switching on an enum value).
3889  //
3890  // Note: We add a successor to a switch that is considered covered yet has no
3891  // case statements if the enumeration has no enumerators.
3892  bool SwitchAlwaysHasSuccessor = false;
3893  SwitchAlwaysHasSuccessor |= switchExclusivelyCovered;
3894  SwitchAlwaysHasSuccessor |= Terminator->isAllEnumCasesCovered() &&
3895  Terminator->getSwitchCaseList();
3896  addSuccessor(SwitchTerminatedBlock, DefaultCaseBlock,
3897  !SwitchAlwaysHasSuccessor);
3898 
3899  // Add the terminator and condition in the switch block.
3900  SwitchTerminatedBlock->setTerminator(Terminator);
3901  Block = SwitchTerminatedBlock;
3902  CFGBlock *LastBlock = addStmt(Terminator->getCond());
3903 
3904  // If the SwitchStmt contains a condition variable, add both the
3905  // SwitchStmt and the condition variable initialization to the CFG.
3906  if (VarDecl *VD = Terminator->getConditionVariable()) {
3907  if (Expr *Init = VD->getInit()) {
3908  autoCreateBlock();
3909  appendStmt(Block, Terminator->getConditionVariableDeclStmt());
3910  LastBlock = addStmt(Init);
3911  maybeAddScopeBeginForVarDecl(LastBlock, VD, Init);
3912  }
3913  }
3914 
3915  // Finally, if the SwitchStmt contains a C++17 init-stmt, add it to the CFG.
3916  if (Stmt *Init = Terminator->getInit()) {
3917  autoCreateBlock();
3918  LastBlock = addStmt(Init);
3919  }
3920 
3921  return LastBlock;
3922 }
3923 
3924 static bool shouldAddCase(bool &switchExclusivelyCovered,
3925  const Expr::EvalResult *switchCond,
3926  const CaseStmt *CS,
3927  ASTContext &Ctx) {
3928  if (!switchCond)
3929  return true;
3930 
3931  bool addCase = false;
3932 
3933  if (!switchExclusivelyCovered) {
3934  if (switchCond->Val.isInt()) {
3935  // Evaluate the LHS of the case value.
3936  const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx);
3937  const llvm::APSInt &condInt = switchCond->Val.getInt();
3938 
3939  if (condInt == lhsInt) {
3940  addCase = true;
3941  switchExclusivelyCovered = true;
3942  }
3943  else if (condInt > lhsInt) {
3944  if (const Expr *RHS = CS->getRHS()) {
3945  // Evaluate the RHS of the case value.
3946  const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx);
3947  if (V2 >= condInt) {
3948  addCase = true;
3949  switchExclusivelyCovered = true;
3950  }
3951  }
3952  }
3953  }
3954  else
3955  addCase = true;
3956  }
3957  return addCase;
3958 }
3959 
3960 CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) {
3961  // CaseStmts are essentially labels, so they are the first statement in a
3962  // block.
3963  CFGBlock *TopBlock = nullptr, *LastBlock = nullptr;
3964 
3965  if (Stmt *Sub = CS->getSubStmt()) {
3966  // For deeply nested chains of CaseStmts, instead of doing a recursion
3967  // (which can blow out the stack), manually unroll and create blocks
3968  // along the way.
3969  while (isa<CaseStmt>(Sub)) {
3970  CFGBlock *currentBlock = createBlock(false);
3971  currentBlock->setLabel(CS);
3972 
3973  if (TopBlock)
3974  addSuccessor(LastBlock, currentBlock);
3975  else
3976  TopBlock = currentBlock;
3977 
3978  addSuccessor(SwitchTerminatedBlock,
3979  shouldAddCase(switchExclusivelyCovered, switchCond,
3980  CS, *Context)
3981  ? currentBlock : nullptr);
3982 
3983  LastBlock = currentBlock;
3984  CS = cast<CaseStmt>(Sub);
3985  Sub = CS->getSubStmt();
3986  }
3987 
3988  addStmt(Sub);
3989  }
3990 
3991  CFGBlock *CaseBlock = Block;
3992  if (!CaseBlock)
3993  CaseBlock = createBlock();
3994 
3995  // Cases statements partition blocks, so this is the top of the basic block we
3996  // were processing (the "case XXX:" is the label).
3997  CaseBlock->setLabel(CS);
3998 
3999  if (badCFG)
4000  return nullptr;
4001 
4002  // Add this block to the list of successors for the block with the switch
4003  // statement.
4004  assert(SwitchTerminatedBlock);
4005  addSuccessor(SwitchTerminatedBlock, CaseBlock,
4006  shouldAddCase(switchExclusivelyCovered, switchCond,
4007  CS, *Context));
4008 
4009  // We set Block to NULL to allow lazy creation of a new block (if necessary)
4010  Block = nullptr;
4011 
4012  if (TopBlock) {
4013  addSuccessor(LastBlock, CaseBlock);
4014  Succ = TopBlock;
4015  } else {
4016  // This block is now the implicit successor of other blocks.
4017  Succ = CaseBlock;
4018  }
4019 
4020  return Succ;
4021 }
4022 
4023 CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) {
4024  if (Terminator->getSubStmt())
4025  addStmt(Terminator->getSubStmt());
4026 
4027  DefaultCaseBlock = Block;
4028 
4029  if (!DefaultCaseBlock)
4030  DefaultCaseBlock = createBlock();
4031 
4032  // Default statements partition blocks, so this is the top of the basic block
4033  // we were processing (the "default:" is the label).
4034  DefaultCaseBlock->setLabel(Terminator);
4035 
4036  if (badCFG)
4037  return nullptr;
4038 
4039  // Unlike case statements, we don't add the default block to the successors
4040  // for the switch statement immediately. This is done when we finish
4041  // processing the switch statement. This allows for the default case
4042  // (including a fall-through to the code after the switch statement) to always
4043  // be the last successor of a switch-terminated block.
4044 
4045  // We set Block to NULL to allow lazy creation of a new block (if necessary)
4046  Block = nullptr;
4047 
4048  // This block is now the implicit successor of other blocks.
4049  Succ = DefaultCaseBlock;
4050 
4051  return DefaultCaseBlock;
4052 }
4053 
4054 CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) {
4055  // "try"/"catch" is a control-flow statement. Thus we stop processing the
4056  // current block.
4057  CFGBlock *TrySuccessor = nullptr;
4058 
4059  if (Block) {
4060  if (badCFG)
4061  return nullptr;
4062  TrySuccessor = Block;
4063  } else TrySuccessor = Succ;
4064 
4065  CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock;
4066 
4067  // Create a new block that will contain the try statement.
4068  CFGBlock *NewTryTerminatedBlock = createBlock(false);
4069  // Add the terminator in the try block.
4070  NewTryTerminatedBlock->setTerminator(Terminator);
4071 
4072  bool HasCatchAll = false;
4073  for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) {
4074  // The code after the try is the implicit successor.
4075  Succ = TrySuccessor;
4076  CXXCatchStmt *CS = Terminator->getHandler(h);
4077  if (CS->getExceptionDecl() == nullptr) {
4078  HasCatchAll = true;
4079  }
4080  Block = nullptr;
4081  CFGBlock *CatchBlock = VisitCXXCatchStmt(CS);
4082  if (!CatchBlock)
4083  return nullptr;
4084  // Add this block to the list of successors for the block with the try
4085  // statement.
4086  addSuccessor(NewTryTerminatedBlock, CatchBlock);
4087  }
4088  if (!HasCatchAll) {
4089  if (PrevTryTerminatedBlock)
4090  addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock);
4091  else
4092  addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
4093  }
4094 
4095  // The code after the try is the implicit successor.
4096  Succ = TrySuccessor;
4097 
4098  // Save the current "try" context.
4099  SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock);
4100  cfg->addTryDispatchBlock(TryTerminatedBlock);
4101 
4102  assert(Terminator->getTryBlock() && "try must contain a non-NULL body");
4103  Block = nullptr;
4104  return addStmt(Terminator->getTryBlock());
4105 }
4106 
4107 CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) {
4108  // CXXCatchStmt are treated like labels, so they are the first statement in a
4109  // block.
4110 
4111  // Save local scope position because in case of exception variable ScopePos
4112  // won't be restored when traversing AST.
4113  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
4114 
4115  // Create local scope for possible exception variable.
4116  // Store scope position. Add implicit destructor.
4117  if (VarDecl *VD = CS->getExceptionDecl()) {
4118  LocalScope::const_iterator BeginScopePos = ScopePos;
4119  addLocalScopeForVarDecl(VD);
4120  addAutomaticObjHandling(ScopePos, BeginScopePos, CS);
4121  }
4122 
4123  if (CS->getHandlerBlock())
4124  addStmt(CS->getHandlerBlock());
4125 
4126  CFGBlock *CatchBlock = Block;
4127  if (!CatchBlock)
4128  CatchBlock = createBlock();
4129 
4130  // CXXCatchStmt is more than just a label. They have semantic meaning
4131  // as well, as they implicitly "initialize" the catch variable. Add
4132  // it to the CFG as a CFGElement so that the control-flow of these
4133  // semantics gets captured.
4134  appendStmt(CatchBlock, CS);
4135 
4136  // Also add the CXXCatchStmt as a label, to mirror handling of regular
4137  // labels.
4138  CatchBlock->setLabel(CS);
4139 
4140  // Bail out if the CFG is bad.
4141  if (badCFG)
4142  return nullptr;
4143 
4144  // We set Block to NULL to allow lazy creation of a new block (if necessary)
4145  Block = nullptr;
4146 
4147  return CatchBlock;
4148 }
4149 
4150 CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) {
4151  // C++0x for-range statements are specified as [stmt.ranged]:
4152  //
4153  // {
4154  // auto && __range = range-init;
4155  // for ( auto __begin = begin-expr,
4156  // __end = end-expr;
4157  // __begin != __end;
4158  // ++__begin ) {
4159  // for-range-declaration = *__begin;
4160  // statement
4161  // }
4162  // }
4163 
4164  // Save local scope position before the addition of the implicit variables.
4165  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
4166 
4167  // Create local scopes and destructors for range, begin and end variables.
4168  if (Stmt *Range = S->getRangeStmt())
4169  addLocalScopeForStmt(Range);
4170  if (Stmt *Begin = S->getBeginStmt())
4171  addLocalScopeForStmt(Begin);
4172  if (Stmt *End = S->getEndStmt())
4173  addLocalScopeForStmt(End);
4174  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), S);
4175 
4176  LocalScope::const_iterator ContinueScopePos = ScopePos;
4177 
4178  // "for" is a control-flow statement. Thus we stop processing the current
4179  // block.
4180  CFGBlock *LoopSuccessor = nullptr;
4181  if (Block) {
4182  if (badCFG)
4183  return nullptr;
4184  LoopSuccessor = Block;
4185  } else
4186  LoopSuccessor = Succ;
4187 
4188  // Save the current value for the break targets.
4189  // All breaks should go to the code following the loop.
4190  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
4191  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
4192 
4193  // The block for the __begin != __end expression.
4194  CFGBlock *ConditionBlock = createBlock(false);
4195  ConditionBlock->setTerminator(S);
4196 
4197  // Now add the actual condition to the condition block.
4198  if (Expr *C = S->getCond()) {
4199  Block = ConditionBlock;
4200  CFGBlock *BeginConditionBlock = addStmt(C);
4201  if (badCFG)
4202  return nullptr;
4203  assert(BeginConditionBlock == ConditionBlock &&
4204  "condition block in for-range was unexpectedly complex");
4205  (void)BeginConditionBlock;
4206  }
4207 
4208  // The condition block is the implicit successor for the loop body as well as
4209  // any code above the loop.
4210  Succ = ConditionBlock;
4211 
4212  // See if this is a known constant.
4213  TryResult KnownVal(true);
4214 
4215  if (S->getCond())
4216  KnownVal = tryEvaluateBool(S->getCond());
4217 
4218  // Now create the loop body.
4219  {
4220  assert(S->getBody());
4221 
4222  // Save the current values for Block, Succ, and continue targets.
4223  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
4224  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
4225 
4226  // Generate increment code in its own basic block. This is the target of
4227  // continue statements.
4228  Block = nullptr;
4229  Succ = addStmt(S->getInc());
4230  if (badCFG)
4231  return nullptr;
4232  ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
4233 
4234  // The starting block for the loop increment is the block that should
4235  // represent the 'loop target' for looping back to the start of the loop.
4236  ContinueJumpTarget.block->setLoopTarget(S);
4237 
4238  // Finish up the increment block and prepare to start the loop body.
4239  assert(Block);
4240  if (badCFG)
4241  return nullptr;
4242  Block = nullptr;
4243 
4244  // Add implicit scope and dtors for loop variable.
4245  addLocalScopeAndDtors(S->getLoopVarStmt());
4246 
4247  // Populate a new block to contain the loop body and loop variable.
4248  addStmt(S->getBody());
4249  if (badCFG)
4250  return nullptr;
4251  CFGBlock *LoopVarStmtBlock = addStmt(S->getLoopVarStmt());
4252  if (badCFG)
4253  return nullptr;
4254 
4255  // This new body block is a successor to our condition block.
4256  addSuccessor(ConditionBlock,
4257  KnownVal.isFalse() ? nullptr : LoopVarStmtBlock);
4258  }
4259 
4260  // Link up the condition block with the code that follows the loop (the
4261  // false branch).
4262  addSuccessor(ConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
4263 
4264  // Add the initialization statements.
4265  Block = createBlock();
4266  addStmt(S->getBeginStmt());
4267  addStmt(S->getEndStmt());
4268  CFGBlock *Head = addStmt(S->getRangeStmt());
4269  if (S->getInit())
4270  Head = addStmt(S->getInit());
4271  return Head;
4272 }
4273 
4274 CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E,
4275  AddStmtChoice asc) {
4276  if (BuildOpts.AddTemporaryDtors) {
4277  // If adding implicit destructors visit the full expression for adding
4278  // destructors of temporaries.
4279  TempDtorContext Context;
4280  VisitForTemporaryDtors(E->getSubExpr(), false, Context);
4281 
4282  // Full expression has to be added as CFGStmt so it will be sequenced
4283  // before destructors of it's temporaries.
4284  asc = asc.withAlwaysAdd(true);
4285  }
4286  return Visit(E->getSubExpr(), asc);
4287 }
4288 
4289 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
4290  AddStmtChoice asc) {
4291  if (asc.alwaysAdd(*this, E)) {
4292  autoCreateBlock();
4293  appendStmt(Block, E);
4294 
4295  findConstructionContexts(
4296  ConstructionContextLayer::create(cfg->getBumpVectorContext(), E),
4297  E->getSubExpr());
4298 
4299  // We do not want to propagate the AlwaysAdd property.
4300  asc = asc.withAlwaysAdd(false);
4301  }
4302  return Visit(E->getSubExpr(), asc);
4303 }
4304 
4305 CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C,
4306  AddStmtChoice asc) {
4307  // If the constructor takes objects as arguments by value, we need to properly
4308  // construct these objects. Construction contexts we find here aren't for the
4309  // constructor C, they're for its arguments only.
4310  findConstructionContextsForArguments(C);
4311 
4312  autoCreateBlock();
4313  appendConstructor(Block, C);
4314 
4315  return VisitChildren(C);
4316 }
4317 
4318 CFGBlock *CFGBuilder::VisitCXXNewExpr(CXXNewExpr *NE,
4319  AddStmtChoice asc) {
4320  autoCreateBlock();
4321  appendStmt(Block, NE);
4322 
4323  findConstructionContexts(
4324  ConstructionContextLayer::create(cfg->getBumpVectorContext(), NE),
4325  const_cast<CXXConstructExpr *>(NE->getConstructExpr()));
4326 
4327  if (NE->getInitializer())
4328  Block = Visit(NE->getInitializer());
4329 
4330  if (BuildOpts.AddCXXNewAllocator)
4331  appendNewAllocator(Block, NE);
4332 
4333  if (NE->isArray())
4334  Block = Visit(NE->getArraySize());
4335 
4337  E = NE->placement_arg_end(); I != E; ++I)
4338  Block = Visit(*I);
4339 
4340  return Block;
4341 }
4342 
4343 CFGBlock *CFGBuilder::VisitCXXDeleteExpr(CXXDeleteExpr *DE,
4344  AddStmtChoice asc) {
4345  autoCreateBlock();
4346  appendStmt(Block, DE);
4347  QualType DTy = DE->getDestroyedType();
4348  if (!DTy.isNull()) {
4349  DTy = DTy.getNonReferenceType();
4350  CXXRecordDecl *RD = Context->getBaseElementType(DTy)->getAsCXXRecordDecl();
4351  if (RD) {
4352  if (RD->isCompleteDefinition() && !RD->hasTrivialDestructor())
4353  appendDeleteDtor(Block, RD, DE);
4354  }
4355  }
4356 
4357  return VisitChildren(DE);
4358 }
4359 
4360 CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
4361  AddStmtChoice asc) {
4362  if (asc.alwaysAdd(*this, E)) {
4363  autoCreateBlock();
4364  appendStmt(Block, E);
4365  // We do not want to propagate the AlwaysAdd property.
4366  asc = asc.withAlwaysAdd(false);
4367  }
4368  return Visit(E->getSubExpr(), asc);
4369 }
4370 
4371 CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
4372  AddStmtChoice asc) {
4373  // If the constructor takes objects as arguments by value, we need to properly
4374  // construct these objects. Construction contexts we find here aren't for the
4375  // constructor C, they're for its arguments only.
4376  findConstructionContextsForArguments(C);
4377 
4378  autoCreateBlock();
4379  appendConstructor(Block, C);
4380  return VisitChildren(C);
4381 }
4382 
4383 CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E,
4384  AddStmtChoice asc) {
4385  if (asc.alwaysAdd(*this, E)) {
4386  autoCreateBlock();
4387  appendStmt(Block, E);
4388  }
4389  return Visit(E->getSubExpr(), AddStmtChoice());
4390 }
4391 
4392 CFGBlock *CFGBuilder::VisitConstantExpr(ConstantExpr *E, AddStmtChoice asc) {
4393  return Visit(E->getSubExpr(), AddStmtChoice());
4394 }
4395 
4396 CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) {
4397  // Lazily create the indirect-goto dispatch block if there isn't one already.
4398  CFGBlock *IBlock = cfg->getIndirectGotoBlock();
4399 
4400  if (!IBlock) {
4401  IBlock = createBlock(false);
4402  cfg->setIndirectGotoBlock(IBlock);
4403  }
4404 
4405  // IndirectGoto is a control-flow statement. Thus we stop processing the
4406  // current block and create a new one.
4407  if (badCFG)
4408  return nullptr;
4409 
4410  Block = createBlock(false);
4411  Block->setTerminator(I);
4412  addSuccessor(Block, IBlock);
4413  return addStmt(I->getTarget());
4414 }
4415 
4416 CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary,
4417  TempDtorContext &Context) {
4418  assert(BuildOpts.AddImplicitDtors && BuildOpts.AddTemporaryDtors);
4419 
4420 tryAgain:
4421  if (!E) {
4422  badCFG = true;
4423  return nullptr;
4424  }
4425  switch (E->getStmtClass()) {
4426  default:
4427  return VisitChildrenForTemporaryDtors(E, Context);
4428 
4429  case Stmt::BinaryOperatorClass:
4430  return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E),
4431  Context);
4432 
4433  case Stmt::CXXBindTemporaryExprClass:
4434  return VisitCXXBindTemporaryExprForTemporaryDtors(
4435  cast<CXXBindTemporaryExpr>(E), BindToTemporary, Context);
4436 
4437  case Stmt::BinaryConditionalOperatorClass:
4438  case Stmt::ConditionalOperatorClass:
4439  return VisitConditionalOperatorForTemporaryDtors(
4440  cast<AbstractConditionalOperator>(E), BindToTemporary, Context);
4441 
4442  case Stmt::ImplicitCastExprClass:
4443  // For implicit cast we want BindToTemporary to be passed further.
4444  E = cast<CastExpr>(E)->getSubExpr();
4445  goto tryAgain;
4446 
4447  case Stmt::CXXFunctionalCastExprClass:
4448  // For functional cast we want BindToTemporary to be passed further.
4449  E = cast<CXXFunctionalCastExpr>(E)->getSubExpr();
4450  goto tryAgain;
4451 
4452  case Stmt::ConstantExprClass:
4453  E = cast<ConstantExpr>(E)->getSubExpr();
4454  goto tryAgain;
4455 
4456  case Stmt::ParenExprClass:
4457  E = cast<ParenExpr>(E)->getSubExpr();
4458  goto tryAgain;
4459 
4460  case Stmt::MaterializeTemporaryExprClass: {
4461  const MaterializeTemporaryExpr* MTE = cast<MaterializeTemporaryExpr>(E);
4462  BindToTemporary = (MTE->getStorageDuration() != SD_FullExpression);
4463  SmallVector<const Expr *, 2> CommaLHSs;
4465  // Find the expression whose lifetime needs to be extended.
4466  E = const_cast<Expr *>(
4467  cast<MaterializeTemporaryExpr>(E)
4468  ->GetTemporaryExpr()
4469  ->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments));
4470  // Visit the skipped comma operator left-hand sides for other temporaries.
4471  for (const Expr *CommaLHS : CommaLHSs) {
4472  VisitForTemporaryDtors(const_cast<Expr *>(CommaLHS),
4473  /*BindToTemporary=*/false, Context);
4474  }
4475  goto tryAgain;
4476  }
4477 
4478  case Stmt::BlockExprClass:
4479  // Don't recurse into blocks; their subexpressions don't get evaluated
4480  // here.
4481  return Block;
4482 
4483  case Stmt::LambdaExprClass: {
4484  // For lambda expressions, only recurse into the capture initializers,
4485  // and not the body.
4486  auto *LE = cast<LambdaExpr>(E);
4487  CFGBlock *B = Block;
4488  for (Expr *Init : LE->capture_inits()) {
4489  if (Init) {
4490  if (CFGBlock *R = VisitForTemporaryDtors(
4491  Init, /*BindToTemporary=*/false, Context))
4492  B = R;
4493  }
4494  }
4495  return B;
4496  }
4497 
4498  case Stmt::CXXDefaultArgExprClass:
4499  E = cast<CXXDefaultArgExpr>(E)->getExpr();
4500  goto tryAgain;
4501 
4502  case Stmt::CXXDefaultInitExprClass:
4503  E = cast<CXXDefaultInitExpr>(E)->getExpr();
4504  goto tryAgain;
4505  }
4506 }
4507 
4508 CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E,
4509  TempDtorContext &Context) {
4510  if (isa<LambdaExpr>(E)) {
4511  // Do not visit the children of lambdas; they have their own CFGs.
4512  return Block;
4513  }
4514 
4515  // When visiting children for destructors we want to visit them in reverse
4516  // order that they will appear in the CFG. Because the CFG is built
4517  // bottom-up, this means we visit them in their natural order, which
4518  // reverses them in the CFG.
4519  CFGBlock *B = Block;
4520  for (Stmt *Child : E->children())
4521  if (Child)
4522  if (CFGBlock *R = VisitForTemporaryDtors(Child, false, Context))
4523  B = R;
4524 
4525  return B;
4526 }
4527 
4528 CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(
4529  BinaryOperator *E, TempDtorContext &Context) {
4530  if (E->isLogicalOp()) {
4531  VisitForTemporaryDtors(E->getLHS(), false, Context);
4532  TryResult RHSExecuted = tryEvaluateBool(E->getLHS());
4533  if (RHSExecuted.isKnown() && E->getOpcode() == BO_LOr)
4534  RHSExecuted.negate();
4535 
4536  // We do not know at CFG-construction time whether the right-hand-side was
4537  // executed, thus we add a branch node that depends on the temporary
4538  // constructor call.
4539  TempDtorContext RHSContext(
4540  bothKnownTrue(Context.KnownExecuted, RHSExecuted));
4541  VisitForTemporaryDtors(E->getRHS(), false, RHSContext);
4542  InsertTempDtorDecisionBlock(RHSContext);
4543 
4544  return Block;
4545  }
4546 
4547  if (E->isAssignmentOp()) {
4548  // For assignment operator (=) LHS expression is visited
4549  // before RHS expression. For destructors visit them in reverse order.
4550  CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
4551  CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
4552  return LHSBlock ? LHSBlock : RHSBlock;
4553  }
4554 
4555  // For any other binary operator RHS expression is visited before
4556  // LHS expression (order of children). For destructors visit them in reverse
4557  // order.
4558  CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
4559  CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
4560  return RHSBlock ? RHSBlock : LHSBlock;
4561 }
4562 
4563 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors(
4564  CXXBindTemporaryExpr *E, bool BindToTemporary, TempDtorContext &Context) {
4565  // First add destructors for temporaries in subexpression.
4566  CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr(), false, Context);
4567  if (!BindToTemporary) {
4568  // If lifetime of temporary is not prolonged (by assigning to constant
4569  // reference) add destructor for it.
4570 
4571  const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor();
4572 
4573  if (Dtor->getParent()->isAnyDestructorNoReturn()) {
4574  // If the destructor is marked as a no-return destructor, we need to
4575  // create a new block for the destructor which does not have as a
4576  // successor anything built thus far. Control won't flow out of this
4577  // block.
4578  if (B) Succ = B;
4579  Block = createNoReturnBlock();
4580  } else if (Context.needsTempDtorBranch()) {
4581  // If we need to introduce a branch, we add a new block that we will hook
4582  // up to a decision block later.
4583  if (B) Succ = B;
4584  Block = createBlock();
4585  } else {
4586  autoCreateBlock();
4587  }
4588  if (Context.needsTempDtorBranch()) {
4589  Context.setDecisionPoint(Succ, E);
4590  }
4591  appendTemporaryDtor(Block, E);
4592 
4593  B = Block;
4594  }
4595  return B;
4596 }
4597 
4598 void CFGBuilder::InsertTempDtorDecisionBlock(const TempDtorContext &Context,
4599  CFGBlock *FalseSucc) {
4600  if (!Context.TerminatorExpr) {
4601  // If no temporary was found, we do not need to insert a decision point.
4602  return;
4603  }
4604  assert(Context.TerminatorExpr);
4605  CFGBlock *Decision = createBlock(false);
4606  Decision->setTerminator(CFGTerminator(Context.TerminatorExpr, true));
4607  addSuccessor(Decision, Block, !Context.KnownExecuted.isFalse());
4608  addSuccessor(Decision, FalseSucc ? FalseSucc : Context.Succ,
4609  !Context.KnownExecuted.isTrue());
4610  Block = Decision;
4611 }
4612 
4613 CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors(
4614  AbstractConditionalOperator *E, bool BindToTemporary,
4615  TempDtorContext &Context) {
4616  VisitForTemporaryDtors(E->getCond(), false, Context);
4617  CFGBlock *ConditionBlock = Block;
4618  CFGBlock *ConditionSucc = Succ;
4619  TryResult ConditionVal = tryEvaluateBool(E->getCond());
4620  TryResult NegatedVal = ConditionVal;
4621  if (NegatedVal.isKnown()) NegatedVal.negate();
4622 
4623  TempDtorContext TrueContext(
4624  bothKnownTrue(Context.KnownExecuted, ConditionVal));
4625  VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary, TrueContext);
4626  CFGBlock *TrueBlock = Block;
4627 
4628  Block = ConditionBlock;
4629  Succ = ConditionSucc;
4630  TempDtorContext FalseContext(
4631  bothKnownTrue(Context.KnownExecuted, NegatedVal));
4632  VisitForTemporaryDtors(E->getFalseExpr(), BindToTemporary, FalseContext);
4633 
4634  if (TrueContext.TerminatorExpr && FalseContext.TerminatorExpr) {
4635  InsertTempDtorDecisionBlock(FalseContext, TrueBlock);
4636  } else if (TrueContext.TerminatorExpr) {
4637  Block = TrueBlock;
4638  InsertTempDtorDecisionBlock(TrueContext);
4639  } else {
4640  InsertTempDtorDecisionBlock(FalseContext);
4641  }
4642  return Block;
4643 }
4644 
4645 /// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has
4646 /// no successors or predecessors. If this is the first block created in the
4647 /// CFG, it is automatically set to be the Entry and Exit of the CFG.
4649  bool first_block = begin() == end();
4650 
4651  // Create the block.
4652  CFGBlock *Mem = getAllocator().Allocate<CFGBlock>();
4653  new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this);
4654  Blocks.push_back(Mem, BlkBVC);
4655 
4656  // If this is the first block, set it as the Entry and Exit.
4657  if (first_block)
4658  Entry = Exit = &back();
4659 
4660  // Return the block.
4661  return &back();
4662 }
4663 
4664 /// buildCFG - Constructs a CFG from an AST.
4665 std::unique_ptr<CFG> CFG::buildCFG(const Decl *D, Stmt *Statement,
4666  ASTContext *C, const BuildOptions &BO) {
4667  CFGBuilder Builder(C, BO);
4668  return Builder.buildCFG(D, Statement);
4669 }
4670 
4671 const CXXDestructorDecl *
4673  switch (getKind()) {
4676  case CFGElement::LoopExit:
4678  case CFGElement::Statement:
4682  case CFGElement::ScopeEnd:
4683  llvm_unreachable("getDestructorDecl should only be used with "
4684  "ImplicitDtors");
4686  const VarDecl *var = castAs<CFGAutomaticObjDtor>().getVarDecl();
4687  QualType ty = var->getType();
4688 
4689  // FIXME: See CFGBuilder::addLocalScopeForVarDecl.
4690  //
4691  // Lifetime-extending constructs are handled here. This works for a single
4692  // temporary in an initializer expression.
4693  if (ty->isReferenceType()) {
4694  if (const Expr *Init = var->getInit()) {
4695  ty = getReferenceInitTemporaryType(Init);
4696  }
4697  }
4698 
4699  while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) {
4700  ty = arrayType->getElementType();
4701  }
4702  const RecordType *recordType = ty->getAs<RecordType>();
4703  const CXXRecordDecl *classDecl =
4704  cast<CXXRecordDecl>(recordType->getDecl());
4705  return classDecl->getDestructor();
4706  }
4707  case CFGElement::DeleteDtor: {
4708  const CXXDeleteExpr *DE = castAs<CFGDeleteDtor>().getDeleteExpr();
4709  QualType DTy = DE->getDestroyedType();
4710  DTy = DTy.getNonReferenceType();
4711  const CXXRecordDecl *classDecl =
4712  astContext.getBaseElementType(DTy)->getAsCXXRecordDecl();
4713  return classDecl->getDestructor();
4714  }
4716  const CXXBindTemporaryExpr *bindExpr =
4717  castAs<CFGTemporaryDtor>().getBindTemporaryExpr();
4718  const CXXTemporary *temp = bindExpr->getTemporary();
4719  return temp->getDestructor();
4720  }
4721  case CFGElement::BaseDtor:
4723  // Not yet supported.
4724  return nullptr;
4725  }
4726  llvm_unreachable("getKind() returned bogus value");
4727 }
4728 
4729 bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const {
4730  if (const CXXDestructorDecl *DD = getDestructorDecl(astContext))
4731  return DD->isNoReturn();
4732  return false;
4733 }
4734 
4735 //===----------------------------------------------------------------------===//
4736 // CFGBlock operations.
4737 //===----------------------------------------------------------------------===//
4738 
4740  : ReachableBlock(IsReachable ? B : nullptr),
4741  UnreachableBlock(!IsReachable ? B : nullptr,
4742  B && IsReachable ? AB_Normal : AB_Unreachable) {}
4743 
4745  : ReachableBlock(B),
4746  UnreachableBlock(B == AlternateBlock ? nullptr : AlternateBlock,
4747  B == AlternateBlock ? AB_Alternate : AB_Normal) {}
4748 
4750  BumpVectorContext &C) {
4751  if (CFGBlock *B = Succ.getReachableBlock())
4752  B->Preds.push_back(AdjacentBlock(this, Succ.isReachable()), C);
4753 
4754  if (CFGBlock *UnreachableB = Succ.getPossiblyUnreachableBlock())
4755  UnreachableB->Preds.push_back(AdjacentBlock(this, false), C);
4756 
4757  Succs.push_back(Succ, C);
4758 }
4759 
4761  const CFGBlock *From, const CFGBlock *To) {
4762  if (F.IgnoreNullPredecessors && !From)
4763  return true;
4764 
4765  if (To && From && F.IgnoreDefaultsWithCoveredEnums) {
4766  // If the 'To' has no label or is labeled but the label isn't a
4767  // CaseStmt then filter this edge.
4768  if (const SwitchStmt *S =
4769  dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) {
4770  if (S->isAllEnumCasesCovered()) {
4771  const Stmt *L = To->getLabel();
4772  if (!L || !isa<CaseStmt>(L))
4773  return true;
4774  }
4775  }
4776  }
4777 
4778  return false;
4779 }
4780 
4781 //===----------------------------------------------------------------------===//
4782 // CFG pretty printing
4783 //===----------------------------------------------------------------------===//
4784 
4785 namespace {
4786 
4787 class StmtPrinterHelper : public PrinterHelper {
4788  using StmtMapTy = llvm::DenseMap<const Stmt *, std::pair<unsigned, unsigned>>;
4789  using DeclMapTy = llvm::DenseMap<const Decl *, std::pair<unsigned, unsigned>>;
4790 
4791  StmtMapTy StmtMap;
4792  DeclMapTy DeclMap;
4793  signed currentBlock = 0;
4794  unsigned currStmt = 0;
4795  const LangOptions &LangOpts;
4796 
4797 public:
4798  StmtPrinterHelper(const CFG* cfg, const LangOptions &LO)
4799  : LangOpts(LO) {
4800  for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) {
4801  unsigned j = 1;
4802  for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ;
4803  BI != BEnd; ++BI, ++j ) {
4804  if (Optional<CFGStmt> SE = BI->getAs<CFGStmt>()) {
4805  const Stmt *stmt= SE->getStmt();
4806  std::pair<unsigned, unsigned> P((*I)->getBlockID(), j);
4807  StmtMap[stmt] = P;
4808 
4809  switch (stmt->getStmtClass()) {
4810  case Stmt::DeclStmtClass:
4811  DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P;
4812  break;
4813  case Stmt::IfStmtClass: {
4814  const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable();
4815  if (var)
4816  DeclMap[var] = P;
4817  break;
4818  }
4819  case Stmt::ForStmtClass: {
4820  const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable();
4821  if (var)
4822  DeclMap[var] = P;
4823  break;
4824  }
4825  case Stmt::WhileStmtClass: {
4826  const VarDecl *var =
4827  cast<WhileStmt>(stmt)->getConditionVariable();
4828  if (var)
4829  DeclMap[var] = P;
4830  break;
4831  }
4832  case Stmt::SwitchStmtClass: {
4833  const VarDecl *var =
4834  cast<SwitchStmt>(stmt)->getConditionVariable();
4835  if (var)
4836  DeclMap[var] = P;
4837  break;
4838  }
4839  case Stmt::CXXCatchStmtClass: {
4840  const VarDecl *var =
4841  cast<CXXCatchStmt>(stmt)->getExceptionDecl();
4842  if (var)
4843  DeclMap[var] = P;
4844  break;
4845  }
4846  default:
4847  break;
4848  }
4849  }
4850  }
4851  }
4852  }
4853 
4854  ~StmtPrinterHelper() override = default;
4855 
4856  const LangOptions &getLangOpts() const { return LangOpts; }
4857  void setBlockID(signed i) { currentBlock = i; }
4858  void setStmtID(unsigned i) { currStmt = i; }
4859 
4860  bool handledStmt(Stmt *S, raw_ostream &OS) override {
4861  StmtMapTy::iterator I = StmtMap.find(S);
4862 
4863  if (I == StmtMap.end())
4864  return false;
4865 
4866  if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
4867  && I->second.second == currStmt) {
4868  return false;
4869  }
4870 
4871  OS << "[B" << I->second.first << "." << I->second.second << "]";
4872  return true;
4873  }
4874 
4875  bool handleDecl(const Decl *D, raw_ostream &OS) {
4876  DeclMapTy::iterator I = DeclMap.find(D);
4877 
4878  if (I == DeclMap.end())
4879  return false;
4880 
4881  if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
4882  && I->second.second == currStmt) {
4883  return false;
4884  }
4885 
4886  OS << "[B" << I->second.first << "." << I->second.second << "]";
4887  return true;
4888  }
4889 };
4890 
4891 class CFGBlockTerminatorPrint
4892  : public StmtVisitor<CFGBlockTerminatorPrint,void> {
4893  raw_ostream &OS;
4894  StmtPrinterHelper* Helper;
4895  PrintingPolicy Policy;
4896 
4897 public:
4898  CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper,
4899  const PrintingPolicy &Policy)
4900  : OS(os), Helper(helper), Policy(Policy) {
4901  this->Policy.IncludeNewlines = false;
4902  }
4903 
4904  void VisitIfStmt(IfStmt *I) {
4905  OS << "if ";
4906  if (Stmt *C = I->getCond())
4907  C->printPretty(OS, Helper, Policy);
4908  }
4909 
4910  // Default case.
4911  void VisitStmt(Stmt *Terminator) {
4912  Terminator->printPretty(OS, Helper, Policy);
4913  }
4914 
4915  void VisitDeclStmt(DeclStmt *DS) {
4916  VarDecl *VD = cast<VarDecl>(DS->getSingleDecl());
4917  OS << "static init " << VD->getName();
4918  }
4919 
4920  void VisitForStmt(ForStmt *F) {
4921  OS << "for (" ;
4922  if (F->getInit())
4923  OS << "...";
4924  OS << "; ";
4925  if (Stmt *C = F->getCond())
4926  C->printPretty(OS, Helper, Policy);
4927  OS << "; ";
4928  if (F->getInc())
4929  OS << "...";
4930  OS << ")";
4931  }
4932 
4933  void VisitWhileStmt(WhileStmt *W) {
4934  OS << "while " ;
4935  if (Stmt *C = W->getCond())
4936  C->printPretty(OS, Helper, Policy);
4937  }
4938 
4939  void VisitDoStmt(DoStmt *D) {
4940  OS << "do ... while ";
4941  if (Stmt *C = D->getCond())
4942  C->printPretty(OS, Helper, Policy);
4943  }
4944 
4945  void VisitSwitchStmt(SwitchStmt *Terminator) {
4946  OS << "switch ";
4947  Terminator->getCond()->printPretty(OS, Helper, Policy);
4948  }
4949 
4950  void VisitCXXTryStmt(CXXTryStmt *CS) {
4951  OS << "try ...";
4952  }
4953 
4954  void VisitSEHTryStmt(SEHTryStmt *CS) {
4955  OS << "__try ...";
4956  }
4957 
4958  void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) {
4959  if (Stmt *Cond = C->getCond())
4960  Cond->printPretty(OS, Helper, Policy);
4961  OS << " ? ... : ...";
4962  }
4963 
4964  void VisitChooseExpr(ChooseExpr *C) {
4965  OS << "__builtin_choose_expr( ";
4966  if (Stmt *Cond = C->getCond())
4967  Cond->printPretty(OS, Helper, Policy);
4968  OS << " )";
4969  }
4970 
4971  void VisitIndirectGotoStmt(IndirectGotoStmt *I) {
4972  OS << "goto *";
4973  if (Stmt *T = I->getTarget())
4974  T->printPretty(OS, Helper, Policy);
4975  }
4976 
4977  void VisitBinaryOperator(BinaryOperator* B) {
4978  if (!B->isLogicalOp()) {
4979  VisitExpr(B);
4980  return;
4981  }
4982 
4983  if (B->getLHS())
4984  B->getLHS()->printPretty(OS, Helper, Policy);
4985 
4986  switch (B->getOpcode()) {
4987  case BO_LOr:
4988  OS << " || ...";
4989  return;
4990  case BO_LAnd:
4991  OS << " && ...";
4992  return;
4993  default:
4994  llvm_unreachable("Invalid logical operator.");
4995  }
4996  }
4997 
4998  void VisitExpr(Expr *E) {
4999  E->printPretty(OS, Helper, Policy);
5000  }
5001 
5002 public:
5003  void print(CFGTerminator T) {
5004  if (T.isTemporaryDtorsBranch())
5005  OS << "(Temp Dtor) ";
5006  Visit(T.getStmt());
5007  }
5008 };
5009 
5010 } // namespace
5011 
5012 static void print_initializer(raw_ostream &OS, StmtPrinterHelper &Helper,
5013  const CXXCtorInitializer *I) {
5014  if (I->isBaseInitializer())
5015  OS << I->getBaseClass()->getAsCXXRecordDecl()->getName();
5016  else if (I->isDelegatingInitializer())
5018  else
5019  OS << I->getAnyMember()->getName();
5020  OS << "(";
5021  if (Expr *IE = I->getInit())
5022  IE->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
5023  OS << ")";
5024 
5025  if (I->isBaseInitializer())
5026  OS << " (Base initializer)";
5027  else if (I->isDelegatingInitializer())
5028  OS << " (Delegating initializer)";
5029  else
5030  OS << " (Member initializer)";
5031 }
5032 
5033 static void print_construction_context(raw_ostream &OS,
5034  StmtPrinterHelper &Helper,
5035  const ConstructionContext *CC) {
5037  switch (CC->getKind()) {
5039  OS << ", ";
5040  const auto *SICC = cast<SimpleConstructorInitializerConstructionContext>(CC);
5041  print_initializer(OS, Helper, SICC->getCXXCtorInitializer());
5042  return;
5043  }
5045  OS << ", ";
5046  const auto *CICC =
5047  cast<CXX17ElidedCopyConstructorInitializerConstructionContext>(CC);
5048  print_initializer(OS, Helper, CICC->getCXXCtorInitializer());
5049  Stmts.push_back(CICC->getCXXBindTemporaryExpr());
5050  break;
5051  }
5053  const auto *SDSCC = cast<SimpleVariableConstructionContext>(CC);
5054  Stmts.push_back(SDSCC->getDeclStmt());
5055  break;
5056  }
5058  const auto *CDSCC = cast<CXX17ElidedCopyVariableConstructionContext>(CC);
5059  Stmts.push_back(CDSCC->getDeclStmt());
5060  Stmts.push_back(CDSCC->getCXXBindTemporaryExpr());
5061  break;
5062  }
5064  const auto *NECC = cast<NewAllocatedObjectConstructionContext>(CC);
5065  Stmts.push_back(NECC->getCXXNewExpr());
5066  break;
5067  }
5069  const auto *RSCC = cast<SimpleReturnedValueConstructionContext>(CC);
5070  Stmts.push_back(RSCC->getReturnStmt());
5071  break;
5072  }
5074  const auto *RSCC =
5075  cast<CXX17ElidedCopyReturnedValueConstructionContext>(CC);
5076  Stmts.push_back(RSCC->getReturnStmt());
5077  Stmts.push_back(RSCC->getCXXBindTemporaryExpr());
5078  break;
5079  }
5081  const auto *TOCC = cast<SimpleTemporaryObjectConstructionContext>(CC);
5082  Stmts.push_back(TOCC->getCXXBindTemporaryExpr());
5083  Stmts.push_back(TOCC->getMaterializedTemporaryExpr());
5084  break;
5085  }
5087  const auto *TOCC = cast<ElidedTemporaryObjectConstructionContext>(CC);
5088  Stmts.push_back(TOCC->getCXXBindTemporaryExpr());
5089  Stmts.push_back(TOCC->getMaterializedTemporaryExpr());
5090  Stmts.push_back(TOCC->getConstructorAfterElision());
5091  break;
5092  }
5094  const auto *ACC = cast<ArgumentConstructionContext>(CC);
5095  if (const Stmt *BTE = ACC->getCXXBindTemporaryExpr()) {
5096  OS << ", ";
5097  Helper.handledStmt(const_cast<Stmt *>(BTE), OS);
5098  }
5099  OS << ", ";
5100  Helper.handledStmt(const_cast<Expr *>(ACC->getCallLikeExpr()), OS);
5101  OS << "+" << ACC->getIndex();
5102  return;
5103  }
5104  }
5105  for (auto I: Stmts)
5106  if (I) {
5107  OS << ", ";
5108  Helper.handledStmt(const_cast<Stmt *>(I), OS);
5109  }
5110 }
5111 
5112 static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
5113  const CFGElement &E) {
5114  if (Optional<CFGStmt> CS = E.getAs<CFGStmt>()) {
5115  const Stmt *S = CS->getStmt();
5116  assert(S != nullptr && "Expecting non-null Stmt");
5117 
5118  // special printing for statement-expressions.
5119  if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) {
5120  const CompoundStmt *Sub = SE->getSubStmt();
5121 
5122  auto Children = Sub->children();
5123  if (Children.begin() != Children.end()) {
5124  OS << "({ ... ; ";
5125  Helper.handledStmt(*SE->getSubStmt()->body_rbegin(),OS);
5126  OS << " })\n";
5127  return;
5128  }
5129  }
5130  // special printing for comma expressions.
5131  if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) {
5132  if (B->getOpcode() == BO_Comma) {
5133  OS << "... , ";
5134  Helper.handledStmt(B->getRHS(),OS);
5135  OS << '\n';
5136  return;
5137  }
5138  }
5139  S->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
5140 
5141  if (auto VTC = E.getAs<CFGCXXRecordTypedCall>()) {
5142  if (isa<CXXOperatorCallExpr>(S))
5143  OS << " (OperatorCall)";
5144  OS << " (CXXRecordTypedCall";
5145  print_construction_context(OS, Helper, VTC->getConstructionContext());
5146  OS << ")";
5147  } else if (isa<CXXOperatorCallExpr>(S)) {
5148  OS << " (OperatorCall)";
5149  } else if (isa<CXXBindTemporaryExpr>(S)) {
5150  OS << " (BindTemporary)";
5151  } else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) {
5152  OS << " (CXXConstructExpr";
5154  print_construction_context(OS, Helper, CE->getConstructionContext());
5155  }
5156  OS << ", " << CCE->getType().getAsString() << ")";
5157  } else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) {
5158  OS << " (" << CE->getStmtClassName() << ", "
5159  << CE->getCastKindName()
5160  << ", " << CE->getType().getAsString()
5161  << ")";
5162  }
5163 
5164  // Expressions need a newline.
5165  if (isa<Expr>(S))
5166  OS << '\n';
5167  } else if (Optional<CFGInitializer> IE = E.getAs<CFGInitializer>()) {
5168  print_initializer(OS, Helper, IE->getInitializer());
5169  OS << '\n';
5170  } else if (Optional<CFGAutomaticObjDtor> DE =
5171  E.getAs<CFGAutomaticObjDtor>()) {
5172  const VarDecl *VD = DE->getVarDecl();
5173  Helper.handleDecl(VD, OS);
5174 
5175  ASTContext &ACtx = VD->getASTContext();
5176  QualType T = VD->getType();
5177  if (T->isReferenceType())
5178  T = getReferenceInitTemporaryType(VD->getInit(), nullptr);
5179  if (const ArrayType *AT = ACtx.getAsArrayType(T))
5180  T = ACtx.getBaseElementType(AT);
5181 
5182  OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()";
5183  OS << " (Implicit destructor)\n";
5184  } else if (Optional<CFGLifetimeEnds> DE = E.getAs<CFGLifetimeEnds>()) {
5185  const VarDecl *VD = DE->getVarDecl();
5186  Helper.handleDecl(VD, OS);
5187 
5188  OS << " (Lifetime ends)\n";
5189  } else if (Optional<CFGLoopExit> LE = E.getAs<CFGLoopExit>()) {
5190  const Stmt *LoopStmt = LE->getLoopStmt();
5191  OS << LoopStmt->getStmtClassName() << " (LoopExit)\n";
5192  } else if (Optional<CFGScopeBegin> SB = E.getAs<CFGScopeBegin>()) {
5193  OS << "CFGScopeBegin(";
5194  if (const VarDecl *VD = SB->getVarDecl())
5195  OS << VD->getQualifiedNameAsString();
5196  OS << ")\n";
5197  } else if (Optional<CFGScopeEnd> SE = E.getAs<CFGScopeEnd>()) {
5198  OS << "CFGScopeEnd(";
5199  if (const VarDecl *VD = SE->getVarDecl())
5200  OS << VD->getQualifiedNameAsString();
5201  OS << ")\n";
5202  } else if (Optional<CFGNewAllocator> NE = E.getAs<CFGNewAllocator>()) {
5203  OS << "CFGNewAllocator(";
5204  if (const CXXNewExpr *AllocExpr = NE->getAllocatorExpr())
5205  AllocExpr->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
5206  OS << ")\n";
5207  } else if (Optional<CFGDeleteDtor> DE = E.getAs<CFGDeleteDtor>()) {
5208  const CXXRecordDecl *RD = DE->getCXXRecordDecl();
5209  if (!RD)
5210  return;
5211  CXXDeleteExpr *DelExpr =
5212  const_cast<CXXDeleteExpr*>(DE->getDeleteExpr());
5213  Helper.handledStmt(cast<Stmt>(DelExpr->getArgument()), OS);
5214  OS << "->~" << RD->getName().str() << "()";
5215  OS << " (Implicit destructor)\n";
5216  } else if (Optional<CFGBaseDtor> BE = E.getAs<CFGBaseDtor>()) {
5217  const CXXBaseSpecifier *BS = BE->getBaseSpecifier();
5218  OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()";
5219  OS << " (Base object destructor)\n";
5220  } else if (Optional<CFGMemberDtor> ME = E.getAs<CFGMemberDtor>()) {
5221  const FieldDecl *FD = ME->getFieldDecl();
5222  const Type *T = FD->getType()->getBaseElementTypeUnsafe();
5223  OS << "this->" << FD->getName();
5224  OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()";
5225  OS << " (Member object destructor)\n";
5226  } else if (Optional<CFGTemporaryDtor> TE = E.getAs<CFGTemporaryDtor>()) {
5227  const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr();
5228  OS << "~";
5229  BT->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
5230  OS << "() (Temporary object destructor)\n";
5231  }
5232 }
5233 
5234 static void print_block(raw_ostream &OS, const CFG* cfg,
5235  const CFGBlock &B,
5236  StmtPrinterHelper &Helper, bool print_edges,
5237  bool ShowColors) {
5238  Helper.setBlockID(B.getBlockID());
5239 
5240  // Print the header.
5241  if (ShowColors)
5242  OS.changeColor(raw_ostream::YELLOW, true);
5243 
5244  OS << "\n [B" << B.getBlockID();
5245 
5246  if (&B == &cfg->getEntry())
5247  OS << " (ENTRY)]\n";
5248  else if (&B == &cfg->getExit())
5249  OS << " (EXIT)]\n";
5250  else if (&B == cfg->getIndirectGotoBlock())
5251  OS << " (INDIRECT GOTO DISPATCH)]\n";
5252  else if (B.hasNoReturnElement())
5253  OS << " (NORETURN)]\n";
5254  else
5255  OS << "]\n";
5256 
5257  if (ShowColors)
5258  OS.resetColor();
5259 
5260  // Print the label of this block.
5261  if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) {
5262  if (print_edges)
5263  OS << " ";
5264 
5265  if (LabelStmt *L = dyn_cast<LabelStmt>(Label))
5266  OS << L->getName();
5267  else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) {
5268  OS << "case ";
5269  if (C->getLHS())
5270  C->getLHS()->printPretty(OS, &Helper,
5271  PrintingPolicy(Helper.getLangOpts()));
5272  if (C->getRHS()) {
5273  OS << " ... ";
5274  C->getRHS()->printPretty(OS, &Helper,
5275  PrintingPolicy(Helper.getLangOpts()));
5276  }
5277  } else if (isa<DefaultStmt>(Label))
5278  OS << "default";
5279  else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) {
5280  OS << "catch (";
5281  if (CS->getExceptionDecl())
5282  CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper.getLangOpts()),
5283  0);
5284  else
5285  OS << "...";
5286  OS << ")";
5287  } else if (SEHExceptStmt *ES = dyn_cast<SEHExceptStmt>(Label)) {
5288  OS << "__except (";
5289  ES->getFilterExpr()->printPretty(OS, &Helper,
5290  PrintingPolicy(Helper.getLangOpts()), 0);
5291  OS << ")";
5292  } else
5293  llvm_unreachable("Invalid label statement in CFGBlock.");
5294 
5295  OS << ":\n";
5296  }
5297 
5298  // Iterate through the statements in the block and print them.
5299  unsigned j = 1;
5300 
5301  for (CFGBlock::const_iterator I = B.begin(), E = B.end() ;
5302  I != E ; ++I, ++j ) {
5303  // Print the statement # in the basic block and the statement itself.
5304  if (print_edges)
5305  OS << " ";
5306 
5307  OS << llvm::format("%3d", j) << ": ";
5308 
5309  Helper.setStmtID(j);
5310 
5311  print_elem(OS, Helper, *I);
5312  }
5313 
5314  // Print the terminator of this block.
5315  if (B.getTerminator()) {
5316  if (ShowColors)
5317  OS.changeColor(raw_ostream::GREEN);
5318 
5319  OS << " T: ";
5320 
5321  Helper.setBlockID(-1);
5322 
5323  PrintingPolicy PP(Helper.getLangOpts());
5324  CFGBlockTerminatorPrint TPrinter(OS, &Helper, PP);
5325  TPrinter.print(B.getTerminator());
5326  OS << '\n';
5327 
5328  if (ShowColors)
5329  OS.resetColor();
5330  }
5331 
5332  if (print_edges) {
5333  // Print the predecessors of this block.
5334  if (!B.pred_empty()) {
5335  const raw_ostream::Colors Color = raw_ostream::BLUE;
5336  if (ShowColors)
5337  OS.changeColor(Color);
5338  OS << " Preds " ;
5339  if (ShowColors)
5340  OS.resetColor();
5341  OS << '(' << B.pred_size() << "):";
5342  unsigned i = 0;
5343 
5344  if (ShowColors)
5345  OS.changeColor(Color);
5346 
5347  for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end();
5348  I != E; ++I, ++i) {
5349  if (i % 10 == 8)
5350  OS << "\n ";
5351 
5352  CFGBlock *B = *I;
5353  bool Reachable = true;
5354  if (!B) {
5355  Reachable = false;
5356  B = I->getPossiblyUnreachableBlock();
5357  }
5358 
5359  OS << " B" << B->getBlockID();
5360  if (!Reachable)
5361  OS << "(Unreachable)";
5362  }
5363 
5364  if (ShowColors)
5365  OS.resetColor();
5366 
5367  OS << '\n';
5368  }
5369 
5370  // Print the successors of this block.
5371  if (!B.succ_empty()) {
5372  const raw_ostream::Colors Color = raw_ostream::MAGENTA;
5373  if (ShowColors)
5374  OS.changeColor(Color);
5375  OS << " Succs ";
5376  if (ShowColors)
5377  OS.resetColor();
5378  OS << '(' << B.succ_size() << "):";
5379  unsigned i = 0;
5380 
5381  if (ShowColors)
5382  OS.changeColor(Color);
5383 
5384  for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end();
5385  I != E; ++I, ++i) {
5386  if (i % 10 == 8)
5387  OS << "\n ";
5388 
5389  CFGBlock *B = *I;
5390 
5391  bool Reachable = true;
5392  if (!B) {
5393  Reachable = false;
5394  B = I->getPossiblyUnreachableBlock();
5395  }
5396 
5397  if (B) {
5398  OS << " B" << B->getBlockID();
5399  if (!Reachable)
5400  OS << "(Unreachable)";
5401  }
5402  else {
5403  OS << " NULL";
5404  }
5405  }
5406 
5407  if (ShowColors)
5408  OS.resetColor();
5409  OS << '\n';
5410  }
5411  }
5412 }
5413 
5414 /// dump - A simple pretty printer of a CFG that outputs to stderr.
5415 void CFG::dump(const LangOptions &LO, bool ShowColors) const {
5416  print(llvm::errs(), LO, ShowColors);
5417 }
5418 
5419 /// print - A simple pretty printer of a CFG that outputs to an ostream.
5420 void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const {
5421  StmtPrinterHelper Helper(this, LO);
5422 
5423  // Print the entry block.
5424  print_block(OS, this, getEntry(), Helper, true, ShowColors);
5425 
5426  // Iterate through the CFGBlocks and print them one by one.
5427  for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) {
5428  // Skip the entry block, because we already printed it.
5429  if (&(**I) == &getEntry() || &(**I) == &getExit())
5430  continue;
5431 
5432  print_block(OS, this, **I, Helper, true, ShowColors);
5433  }
5434 
5435  // Print the exit block.
5436  print_block(OS, this, getExit(), Helper, true, ShowColors);
5437  OS << '\n';
5438  OS.flush();
5439 }
5440 
5441 /// dump - A simply pretty printer of a CFGBlock that outputs to stderr.
5442 void CFGBlock::dump(const CFG* cfg, const LangOptions &LO,
5443  bool ShowColors) const {
5444  print(llvm::errs(), cfg, LO, ShowColors);
5445 }
5446 
5447 LLVM_DUMP_METHOD void CFGBlock::dump() const {
5448  dump(getParent(), LangOptions(), false);
5449 }
5450 
5451 /// print - A simple pretty printer of a CFGBlock that outputs to an ostream.
5452 /// Generally this will only be called from CFG::print.
5453 void CFGBlock::print(raw_ostream &OS, const CFG* cfg,
5454  const LangOptions &LO, bool ShowColors) const {
5455  StmtPrinterHelper Helper(cfg, LO);
5456  print_block(OS, cfg, *this, Helper, true, ShowColors);
5457  OS << '\n';
5458 }
5459 
5460 /// printTerminator - A simple pretty printer of the terminator of a CFGBlock.
5461 void CFGBlock::printTerminator(raw_ostream &OS,
5462  const LangOptions &LO) const {
5463  CFGBlockTerminatorPrint TPrinter(OS, nullptr, PrintingPolicy(LO));
5464  TPrinter.print(getTerminator());
5465 }
5466 
5468  Stmt *Terminator = this->Terminator;
5469  if (!Terminator)
5470  return nullptr;
5471 
5472  Expr *E = nullptr;
5473 
5474  switch (Terminator->getStmtClass()) {
5475  default:
5476  break;
5477 
5478  case Stmt::CXXForRangeStmtClass:
5479  E = cast<CXXForRangeStmt>(Terminator)->getCond();
5480  break;
5481 
5482  case Stmt::ForStmtClass:
5483  E = cast<ForStmt>(Terminator)->getCond();
5484  break;
5485 
5486  case Stmt::WhileStmtClass:
5487  E = cast<WhileStmt>(Terminator)->getCond();
5488  break;
5489 
5490  case Stmt::DoStmtClass:
5491  E = cast<DoStmt>(Terminator)->getCond();
5492  break;
5493 
5494  case Stmt::IfStmtClass:
5495  E = cast<IfStmt>(Terminator)->getCond();
5496  break;
5497 
5498  case Stmt::ChooseExprClass:
5499  E = cast<ChooseExpr>(Terminator)->getCond();
5500  break;
5501 
5502  case Stmt::IndirectGotoStmtClass:
5503  E = cast<IndirectGotoStmt>(Terminator)->getTarget();
5504  break;
5505 
5506  case Stmt::SwitchStmtClass:
5507  E = cast<SwitchStmt>(Terminator)->getCond();
5508  break;
5509 
5510  case Stmt::BinaryConditionalOperatorClass:
5511  E = cast<BinaryConditionalOperator>(Terminator)->getCond();
5512  break;
5513 
5514  case Stmt::ConditionalOperatorClass:
5515  E = cast<ConditionalOperator>(Terminator)->getCond();
5516  break;
5517 
5518  case Stmt::BinaryOperatorClass: // '&&' and '||'
5519  E = cast<BinaryOperator>(Terminator)->getLHS();
5520  break;
5521 
5522  case Stmt::ObjCForCollectionStmtClass:
5523  return Terminator;
5524  }
5525 
5526  if (!StripParens)
5527  return E;
5528 
5529  return E ? E->IgnoreParens() : nullptr;
5530 }
5531 
5532 //===----------------------------------------------------------------------===//
5533 // CFG Graphviz Visualization
5534 //===----------------------------------------------------------------------===//
5535 
5536 #ifndef NDEBUG
5537 static StmtPrinterHelper* GraphHelper;
5538 #endif
5539 
5540 void CFG::viewCFG(const LangOptions &LO) const {
5541 #ifndef NDEBUG
5542  StmtPrinterHelper H(this, LO);
5543  GraphHelper = &H;
5544  llvm::ViewGraph(this,"CFG");
5545  GraphHelper = nullptr;
5546 #endif
5547 }
5548 
5549 namespace llvm {
5550 
5551 template<>
5552 struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits {
5553  DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
5554 
5555  static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) {
5556 #ifndef NDEBUG
5557  std::string OutSStr;
5558  llvm::raw_string_ostream Out(OutSStr);
5559  print_block(Out,Graph, *Node, *GraphHelper, false, false);
5560  std::string& OutStr = Out.str();
5561 
5562  if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
5563 
5564  // Process string output to make it nicer...
5565  for (unsigned i = 0; i != OutStr.length(); ++i)
5566  if (OutStr[i] == '\n') { // Left justify
5567  OutStr[i] = '\\';
5568  OutStr.insert(OutStr.begin()+i+1, 'l');
5569  }
5570 
5571  return OutStr;
5572 #else
5573  return {};
5574 #endif
5575  }
5576 };
5577 
5578 } // namespace llvm
Expr * getInc()
Definition: Stmt.h:2270
unsigned getNumSemanticExprs() const
Definition: Expr.h:5363
const Expr * getSubExpr() const
Definition: Expr.h:890
bool isBaseInitializer() const
Determine whether this initializer is initializing a base class.
Definition: DeclCXX.h:2325
bool isNoReturn() const
Determines whether this function is known to be &#39;noreturn&#39;, through an attribute on its declaration o...
Definition: Decl.cpp:2934
Defines the clang::ASTContext interface.
const BlockDecl * getBlockDecl() const
Definition: Expr.h:5191
Represents C++ allocator call.
Definition: CFG.h:240
const CXXDestructorDecl * getDestructor() const
Definition: ExprCXX.h:1196
Represents a function declaration or definition.
Definition: Decl.h:1738
Expr * getInit() const
Get the initializer.
Definition: DeclCXX.h:2454
CompoundStmt * getBlock() const
Definition: Stmt.h:3010
A class which contains all the information about a particular captured value.
Definition: Decl.h:3864
pred_iterator pred_end()
Definition: CFG.h:734
PointerType - C99 6.7.5.1 - Pointer Declarators.
Definition: Type.h:2540
QualType getPointeeType() const
Definition: Type.h:2553
A (possibly-)qualified type.
Definition: Type.h:638
bool isBlockPointerType() const
Definition: Type.h:6307
base_class_range bases()
Definition: DeclCXX.h:823
Expr * getCond() const
Definition: Expr.h:4022
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:76
bool operator==(CanQual< T > x, CanQual< U > y)
Expr * getCond()
Definition: Stmt.h:2112
DOTGraphTraits(bool isSimple=false)
Definition: CFG.cpp:5553
ElementList::iterator iterator
Definition: CFG.h:695
succ_iterator succ_begin()
Definition: CFG.h:751
CompoundStmt * getSubStmt()
Definition: Expr.h:3817
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:2265
bool EvaluateAsInt(EvalResult &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...
Stmt - This represents one statement.
Definition: Stmt.h:66
FunctionType - C99 6.7.5.3 - Function Declarators.
Definition: Type.h:3358
CXXCatchStmt * getHandler(unsigned i)
Definition: StmtCXX.h:104
CFGBlock & getEntry()
Definition: CFG.h:1093
IfStmt - This represents an if/then/else.
Definition: Stmt.h:1687
StorageClass getStorageClass() const
Returns the storage class as written in the source.
Definition: Decl.h:1020
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:2767
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:3322
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:6248
void appendLifetimeEnds(VarDecl *VD, Stmt *S, BumpVectorContext &C)
Definition: CFG.h:932
The base class of the type hierarchy.
Definition: Type.h:1407
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:2815
iterator begin()
Definition: CFG.h:703
Represents a call to a C++ constructor.
Definition: ExprCXX.h:1262
unsigned IgnoreDefaultsWithCoveredEnums
Definition: CFG.h:779
Represents a C++ constructor within a class.
Definition: DeclCXX.h:2484
Represents a prvalue temporary that is written into memory so that a reference can bind to it...
Definition: ExprCXX.h:4156
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:3169
unsigned succ_size() const
Definition: CFG.h:769
const CXXDestructorDecl * getDestructorDecl(ASTContext &astContext) const
Definition: CFG.cpp:4672
Stmt * getSubStmt()
Definition: Stmt.h:1555
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:1884
Represents a variable declaration or definition.
Definition: Decl.h:813
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6755
CFGBlock * getReachableBlock() const
Get the reachable block, if one exists.
Definition: CFG.h:640
const char * getName() const
Definition: Stmt.cpp:348
Stmt * getThen()
Definition: Stmt.h:1774
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:5112
A C++ throw-expression (C++ [except.throw]).
Definition: ExprCXX.h:1015
Represents an expression – generally a full-expression – that introduces cleanups to be run at the ...
Definition: ExprCXX.h:3089
static bool isAssignmentOp(Opcode Opc)
Definition: Expr.h:3410
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:1593
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:2210
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:2657
DeclStmt * getConditionVariableDeclStmt()
If this SwitchStmt has a condition variable, return the faux DeclStmt associated with the creation of...
Definition: Stmt.h:2003
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:155
void setLoopTarget(const Stmt *loopTarget)
Definition: CFG.h:837
static std::string getNodeLabel(const CFGBlock *Node, const CFG *Graph)
Definition: CFG.cpp:5555
field_range fields() const
Definition: Decl.h:3784
Represents a member of a struct/union/class.
Definition: Decl.h:2579
TypeSourceInfo * getTypeSourceInfo() const
Returns the declarator information for a base class or delegating initializer.
Definition: DeclCXX.h:2386
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:5461
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:6311
const CXXConstructExpr * getConstructExpr() const
Returns the CXXConstructExpr from this new-expression, or null.
Definition: ExprCXX.h:2102
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:2040
Expr * getSubExpr()
Definition: Expr.h:3050
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:2339
Describes an C or C++ initializer list.
Definition: Expr.h:4185
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:2040
ForStmt - This represents a &#39;for (init;cond;inc)&#39; stmt.
Definition: Stmt.h:2237
APValue Val
Val - This is the value the expression can be folded to.
Definition: Expr.h:573
LabelDecl * getDecl() const
Definition: Stmt.h:1610
Forward-declares and imports various common LLVM datatypes that clang wants to use unqualified...
void print(raw_ostream &OS, const PrintingPolicy &Policy, const Twine &PlaceHolder=Twine(), unsigned Indentation=0) const
capture_init_iterator capture_init_begin()
Retrieve the first initialization argument for this lambda expression (which initializes the first ca...
Definition: ExprCXX.h:1794
Expr * getInitializer()
The initializer of this new-expression.
Definition: ExprCXX.h:2090
Stmt * getBody()
Definition: Stmt.h:2271
CFGCallback * Observer
Definition: CFG.h:1016
child_range children()
Definition: Stmt.cpp:237
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:1560
A builtin binary operation expression such as "x + y" or "x <= y".
Definition: Expr.h:3287
Stmt * getInit()
Definition: Stmt.h:2250
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:5453
Scope - A scope is a transient data structure that is used while parsing the program.
Definition: Scope.h:41
const Type * getTypePtr() const
Retrieves a pointer to the underlying (unqualified) type.
Definition: Type.h:6075
CaseStmt - Represent a case statement.
Definition: Stmt.h:1394
void appendLoopExit(const Stmt *LoopStmt, BumpVectorContext &C)
Definition: CFG.h:936
Expr * getCond()
Definition: Stmt.h:2269
bool isInt() const
Definition: APValue.h:239
CastExpr - Base class for type casts, including both implicit casts (ImplicitCastExpr) and explicit c...
Definition: Expr.h:2998
Represents binding an expression to a temporary.
Definition: ExprCXX.h:1217
CXXTemporary * getTemporary()
Definition: ExprCXX.h:1236
FieldDecl * getAnyMember() const
Definition: DeclCXX.h:2398
A C++ lambda expression, which produces a function object (of unspecified type) that can be invoked l...
Definition: ExprCXX.h:1649
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:1341
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:902
bool getNoReturn() const
Definition: Type.h:3515
Stmt * getBody()
Definition: Stmt.h:1958
Stmt * getInit()
Definition: Stmt.h:1830
arg_iterator placement_arg_end()
Definition: ExprCXX.h:2131
Iterator for iterating over Stmt * arrays that contain only Expr *.
Definition: Stmt.h:983
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:1241
CXXRecordDecl * getAsCXXRecordDecl() const
Retrieves the CXXRecordDecl that this type refers to, either because the type is a RecordType or beca...
Definition: Type.cpp:1613
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3690
bool isDelegatingInitializer() const
Determine whether this initializer is creating a delegating constructor.
Definition: DeclCXX.h:2353
UnaryExprOrTypeTraitExpr - expression with either a type or (unevaluated) expression operand...
Definition: Expr.h:2222
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:3924
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:904
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:4729
This represents one expression.
Definition: Expr.h:106
Defines the clang::LangOptions interface.
Stmt * getTerminatorCondition(bool StripParens=true)
Definition: CFG.cpp:5467
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:1581
BlockExpr - Adaptor class for mixing a BlockDecl with expressions.
Definition: Expr.h:5177
Represents a C++ destructor within a class.
Definition: DeclCXX.h:2706
bool succ_empty() const
Definition: CFG.h:770
VarDecl * getExceptionDecl() const
Definition: StmtCXX.h:50
Expr * getCallee()
Definition: Expr.h:2514
unsigned getNumInits() const
Definition: Expr.h:4215
Represents C++ constructor call.
Definition: CFG.h:151
QualType getArgumentType() const
Definition: Expr.h:2259
#define bool
Definition: stdbool.h:31
Stmt * getBody()
Definition: Stmt.h:2124
const CompoundStmt * getSynchBody() const
Definition: StmtObjC.h:282
ElementList::const_iterator const_iterator
Definition: CFG.h:696
Expr * getRHS()
Definition: Stmt.h:1495
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
FunctionDecl * getDirectCallee()
If the callee is a FunctionDecl, return it. Otherwise return null.
Definition: Expr.h:2532
const AstTypeMatcher< ArrayType > arrayType
Matches all kinds of arrays.
std::reverse_iterator< body_iterator > reverse_body_iterator
Definition: Stmt.h:1309
QualType getType() const
Definition: Expr.h:128
static void print_initializer(raw_ostream &OS, StmtPrinterHelper &Helper, const CXXCtorInitializer *I)
Definition: CFG.cpp:5012
LabelDecl * getLabel() const
Definition: Stmt.h:2317
StorageDuration getStorageDuration() const
Retrieve the storage duration for the materialized temporary.
Definition: ExprCXX.h:4200
An expression that sends a message to the given Objective-C object or class.
Definition: ExprObjC.h:904
SwitchCase * getSwitchCaseList()
Definition: Stmt.h:2015
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:1896
static bool CanThrow(Expr *E, ASTContext &Ctx)
Definition: CFG.cpp:2407
const Type * getBaseElementTypeUnsafe() const
Get the base element type of this type, potentially discarding type qualifiers.
Definition: Type.h:6695
Expr * getCond()
Definition: Stmt.h:1762
ValueDecl * getDecl()
Definition: Expr.h:1114
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:222
const Expr * getSubExpr() const
Definition: ExprCXX.h:1240
bool isNull() const
Return true if this QualType doesn&#39;t point to a type yet.
Definition: Type.h:703
DoStmt - This represents a &#39;do/while&#39; stmt.
Definition: Stmt.h:2185
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:1197
RecordDecl * getDecl() const
Definition: Type.h:4383
Expr * getArgument()
Definition: ExprCXX.h:2212
void appendStmt(Stmt *statement, BumpVectorContext &C)
Definition: CFG.h:873
bool EvaluateAsRValue(EvalResult &Result, const ASTContext &Ctx, bool InConstantContext=false) const
EvaluateAsRValue - Return true if this is a constant which we can fold to an rvalue using any crazy t...
CFGTerminator getTerminator()
Definition: CFG.h:840
OpaqueValueExpr - An expression referring to an opaque object of a fixed type and value class...
Definition: Expr.h:945
Kind
PseudoObjectExpr - An expression which accesses a pseudo-object l-value.
Definition: Expr.h:5299
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:1926
Represents a C++ temporary.
Definition: ExprCXX.h:1185
Represents a new-expression for memory allocation and constructor calls, e.g: "new CXXNewExpr(foo)"...
Definition: ExprCXX.h:1914
Expr * getLHS()
Definition: Stmt.h:1483
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:4665
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:1783
DeclStmt - Adaptor class for mixing declarations with statements and expressions. ...
Definition: Stmt.h:1143
bool PruneTriviallyFalseEdges
Definition: CFG.h:1017
reverse_body_iterator body_rend()
Definition: Stmt.h:1315
QualType getBaseElementType(const ArrayType *VAT) const
Return the innermost element type of an array type.
const ConstantArrayType * getAsConstantArrayType(QualType T) const
Definition: ASTContext.h:2413
Expr * getCond()
Definition: Stmt.h:1946
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:183
static void print_block(raw_ostream &OS, const CFG *cfg, const CFGBlock &B, StmtPrinterHelper &Helper, bool print_edges, bool ShowColors)
Definition: CFG.cpp:5234
const ArrayType * getAsArrayType(QualType T) const
Type Query functions.
bool isArray() const
Definition: ExprCXX.h:2038
decl_iterator decl_begin()
Definition: Stmt.h:1192
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:134
reverse_decl_iterator decl_rbegin()
Definition: Stmt.h:1199
ImplicitCastExpr - Allows us to explicitly represent implicit type conversions, which have no direct ...
Definition: Expr.h:3115
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:2536
Expr ** getInits()
Retrieve the set of initializers.
Definition: Expr.h:4218
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:3407
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:965
DeclStmt * getConditionVariableDeclStmt()
If this WhileStmt has a condition variable, return the faux DeclStmt associated with the creation of ...
Definition: Stmt.h:2152
void dump() const
Definition: CFG.cpp:5447
succ_iterator succ_end()
Definition: CFG.h:752
StmtExpr - This is the GNU Statement Expression extension: ({int X=4; X;}).
Definition: Expr.h:3801
bool isArgumentType() const
Definition: Expr.h:2258
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:3327
Defines various enumerations that describe declaration and type specifiers.
AddrLabelExpr - The GNU address of label extension, representing &&label.
Definition: Expr.h:3757
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:3698
Dataflow Directional Tag Classes.
child_range children()
VarDecl * getConditionVariable()
Retrieve the variable declared in this "while" statement, if any.
Definition: Stmt.cpp:1021
DeclContext - This is used only as base class of specific decl types that can act as declaration cont...
Definition: DeclBase.h:1262
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:2170
ArrayRef< Capture > captures() const
Definition: Decl.h:3985
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
const Stmt * stripLabelLikeStatements() const
Strip off all label-like statements.
Definition: Stmt.cpp:169
static const VariableArrayType * FindVA(const Type *t)
Definition: CFG.cpp:1260
void appendCXXRecordTypedCall(Expr *E, const ConstructionContext *CC, BumpVectorContext &C)
Definition: CFG.h:882
const Expr * getInit() const
Definition: Decl.h:1220
unsigned pred_size() const
Definition: CFG.h:772
StmtClass getStmtClass() const
Definition: Stmt.h:1029
static StmtPrinterHelper * GraphHelper
Definition: CFG.cpp:5537
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:2266
SEHExceptStmt * getExceptHandler() const
Returns 0 if not defined.
Definition: Stmt.cpp:1113
const Decl * getSingleDecl() const
Definition: Stmt.h:1158
FunctionType::ExtInfo getFunctionExtInfo(const Type &t)
Definition: Type.h:6200
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:1156
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:1818
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:2693
llvm::APInt getValue() const
Definition: Expr.h:1292
Represents a __leave statement.
Definition: Stmt.h:3070
LabelDecl * getLabel() const
Definition: Expr.h:3779
SwitchStmt - This represents a &#39;switch&#39; stmt.
Definition: Stmt.h:1886
Pointer to a block type.
Definition: Type.h:2642
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:4373
bool body_empty() const
Definition: Stmt.h:1268
Represents Objective-C&#39;s collection statement.
Definition: StmtObjC.h:24
AbstractConditionalOperator - An abstract base class for ConditionalOperator and BinaryConditionalOpe...
Definition: Expr.h:3540
Represents a C++ base or member initializer.
Definition: DeclCXX.h:2256
reverse_decl_iterator decl_rend()
Definition: Stmt.h:1203
const ConstructionContextItem & getItem() const
Stmt * getInit()
Definition: Stmt.h:1967
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:5420
CanQualType BoundMemberTy
Definition: ASTContext.h:1045
decl_range decls()
Definition: Stmt.h:1186
static void print_construction_context(raw_ostream &OS, StmtPrinterHelper &Helper, const ConstructionContext *CC)
Definition: CFG.cpp:5033
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:2128
DeclStmt * getRangeStmt()
Definition: StmtCXX.h:154
Expr * getRHS() const
Definition: Expr.h:4026
SEHFinallyStmt * getFinallyHandler() const
Definition: Stmt.cpp:1117