clang  8.0.0svn
CFG.cpp
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1 //===- CFG.cpp - Classes for representing and building CFGs ---------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines the CFG and CFGBuilder classes for representing and
11 // building Control-Flow Graphs (CFGs) from ASTs.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "clang/Analysis/CFG.h"
16 #include "clang/AST/ASTContext.h"
17 #include "clang/AST/Attr.h"
18 #include "clang/AST/Decl.h"
19 #include "clang/AST/DeclBase.h"
20 #include "clang/AST/DeclCXX.h"
21 #include "clang/AST/DeclGroup.h"
22 #include "clang/AST/Expr.h"
23 #include "clang/AST/ExprCXX.h"
26 #include "clang/AST/Stmt.h"
27 #include "clang/AST/StmtCXX.h"
28 #include "clang/AST/StmtObjC.h"
29 #include "clang/AST/StmtVisitor.h"
30 #include "clang/AST/Type.h"
33 #include "clang/Basic/Builtins.h"
35 #include "clang/Basic/LLVM.h"
38 #include "clang/Basic/Specifiers.h"
39 #include "llvm/ADT/APInt.h"
40 #include "llvm/ADT/APSInt.h"
41 #include "llvm/ADT/ArrayRef.h"
42 #include "llvm/ADT/DenseMap.h"
43 #include "llvm/ADT/Optional.h"
44 #include "llvm/ADT/STLExtras.h"
45 #include "llvm/ADT/SetVector.h"
46 #include "llvm/ADT/SmallPtrSet.h"
47 #include "llvm/ADT/SmallVector.h"
48 #include "llvm/Support/Allocator.h"
49 #include "llvm/Support/Casting.h"
50 #include "llvm/Support/Compiler.h"
51 #include "llvm/Support/DOTGraphTraits.h"
52 #include "llvm/Support/ErrorHandling.h"
53 #include "llvm/Support/Format.h"
54 #include "llvm/Support/GraphWriter.h"
55 #include "llvm/Support/SaveAndRestore.h"
56 #include "llvm/Support/raw_ostream.h"
57 #include <cassert>
58 #include <memory>
59 #include <string>
60 #include <tuple>
61 #include <utility>
62 #include <vector>
63 
64 using namespace clang;
65 
67  if (VarDecl *VD = dyn_cast<VarDecl>(D))
68  if (Expr *Ex = VD->getInit())
69  return Ex->getSourceRange().getEnd();
70  return D->getLocation();
71 }
72 
73 /// Helper for tryNormalizeBinaryOperator. Attempts to extract an IntegerLiteral
74 /// or EnumConstantDecl from the given Expr. If it fails, returns nullptr.
75 static const Expr *tryTransformToIntOrEnumConstant(const Expr *E) {
76  E = E->IgnoreParens();
77  if (isa<IntegerLiteral>(E))
78  return E;
79  if (auto *DR = dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))
80  return isa<EnumConstantDecl>(DR->getDecl()) ? DR : nullptr;
81  return nullptr;
82 }
83 
84 /// Tries to interpret a binary operator into `Decl Op Expr` form, if Expr is
85 /// an integer literal or an enum constant.
86 ///
87 /// If this fails, at least one of the returned DeclRefExpr or Expr will be
88 /// null.
89 static std::tuple<const DeclRefExpr *, BinaryOperatorKind, const Expr *>
91  BinaryOperatorKind Op = B->getOpcode();
92 
93  const Expr *MaybeDecl = B->getLHS();
94  const Expr *Constant = tryTransformToIntOrEnumConstant(B->getRHS());
95  // Expr looked like `0 == Foo` instead of `Foo == 0`
96  if (Constant == nullptr) {
97  // Flip the operator
98  if (Op == BO_GT)
99  Op = BO_LT;
100  else if (Op == BO_GE)
101  Op = BO_LE;
102  else if (Op == BO_LT)
103  Op = BO_GT;
104  else if (Op == BO_LE)
105  Op = BO_GE;
106 
107  MaybeDecl = B->getRHS();
108  Constant = tryTransformToIntOrEnumConstant(B->getLHS());
109  }
110 
111  auto *D = dyn_cast<DeclRefExpr>(MaybeDecl->IgnoreParenImpCasts());
112  return std::make_tuple(D, Op, Constant);
113 }
114 
115 /// For an expression `x == Foo && x == Bar`, this determines whether the
116 /// `Foo` and `Bar` are either of the same enumeration type, or both integer
117 /// literals.
118 ///
119 /// It's an error to pass this arguments that are not either IntegerLiterals
120 /// or DeclRefExprs (that have decls of type EnumConstantDecl)
121 static bool areExprTypesCompatible(const Expr *E1, const Expr *E2) {
122  // User intent isn't clear if they're mixing int literals with enum
123  // constants.
124  if (isa<IntegerLiteral>(E1) != isa<IntegerLiteral>(E2))
125  return false;
126 
127  // Integer literal comparisons, regardless of literal type, are acceptable.
128  if (isa<IntegerLiteral>(E1))
129  return true;
130 
131  // IntegerLiterals are handled above and only EnumConstantDecls are expected
132  // beyond this point
133  assert(isa<DeclRefExpr>(E1) && isa<DeclRefExpr>(E2));
134  auto *Decl1 = cast<DeclRefExpr>(E1)->getDecl();
135  auto *Decl2 = cast<DeclRefExpr>(E2)->getDecl();
136 
137  assert(isa<EnumConstantDecl>(Decl1) && isa<EnumConstantDecl>(Decl2));
138  const DeclContext *DC1 = Decl1->getDeclContext();
139  const DeclContext *DC2 = Decl2->getDeclContext();
140 
141  assert(isa<EnumDecl>(DC1) && isa<EnumDecl>(DC2));
142  return DC1 == DC2;
143 }
144 
145 namespace {
146 
147 class CFGBuilder;
148 
149 /// The CFG builder uses a recursive algorithm to build the CFG. When
150 /// we process an expression, sometimes we know that we must add the
151 /// subexpressions as block-level expressions. For example:
152 ///
153 /// exp1 || exp2
154 ///
155 /// When processing the '||' expression, we know that exp1 and exp2
156 /// need to be added as block-level expressions, even though they
157 /// might not normally need to be. AddStmtChoice records this
158 /// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then
159 /// the builder has an option not to add a subexpression as a
160 /// block-level expression.
161 class AddStmtChoice {
162 public:
163  enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 };
164 
165  AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {}
166 
167  bool alwaysAdd(CFGBuilder &builder,
168  const Stmt *stmt) const;
169 
170  /// Return a copy of this object, except with the 'always-add' bit
171  /// set as specified.
172  AddStmtChoice withAlwaysAdd(bool alwaysAdd) const {
173  return AddStmtChoice(alwaysAdd ? AlwaysAdd : NotAlwaysAdd);
174  }
175 
176 private:
177  Kind kind;
178 };
179 
180 /// LocalScope - Node in tree of local scopes created for C++ implicit
181 /// destructor calls generation. It contains list of automatic variables
182 /// declared in the scope and link to position in previous scope this scope
183 /// began in.
184 ///
185 /// The process of creating local scopes is as follows:
186 /// - Init CFGBuilder::ScopePos with invalid position (equivalent for null),
187 /// - Before processing statements in scope (e.g. CompoundStmt) create
188 /// LocalScope object using CFGBuilder::ScopePos as link to previous scope
189 /// and set CFGBuilder::ScopePos to the end of new scope,
190 /// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points
191 /// at this VarDecl,
192 /// - For every normal (without jump) end of scope add to CFGBlock destructors
193 /// for objects in the current scope,
194 /// - For every jump add to CFGBlock destructors for objects
195 /// between CFGBuilder::ScopePos and local scope position saved for jump
196 /// target. Thanks to C++ restrictions on goto jumps we can be sure that
197 /// jump target position will be on the path to root from CFGBuilder::ScopePos
198 /// (adding any variable that doesn't need constructor to be called to
199 /// LocalScope can break this assumption),
200 ///
201 class LocalScope {
202 public:
203  friend class const_iterator;
204 
205  using AutomaticVarsTy = BumpVector<VarDecl *>;
206 
207  /// const_iterator - Iterates local scope backwards and jumps to previous
208  /// scope on reaching the beginning of currently iterated scope.
209  class const_iterator {
210  const LocalScope* Scope = nullptr;
211 
212  /// VarIter is guaranteed to be greater then 0 for every valid iterator.
213  /// Invalid iterator (with null Scope) has VarIter equal to 0.
214  unsigned VarIter = 0;
215 
216  public:
217  /// Create invalid iterator. Dereferencing invalid iterator is not allowed.
218  /// Incrementing invalid iterator is allowed and will result in invalid
219  /// iterator.
220  const_iterator() = default;
221 
222  /// Create valid iterator. In case when S.Prev is an invalid iterator and
223  /// I is equal to 0, this will create invalid iterator.
224  const_iterator(const LocalScope& S, unsigned I)
225  : Scope(&S), VarIter(I) {
226  // Iterator to "end" of scope is not allowed. Handle it by going up
227  // in scopes tree possibly up to invalid iterator in the root.
228  if (VarIter == 0 && Scope)
229  *this = Scope->Prev;
230  }
231 
232  VarDecl *const* operator->() const {
233  assert(Scope && "Dereferencing invalid iterator is not allowed");
234  assert(VarIter != 0 && "Iterator has invalid value of VarIter member");
235  return &Scope->Vars[VarIter - 1];
236  }
237 
238  const VarDecl *getFirstVarInScope() const {
239  assert(Scope && "Dereferencing invalid iterator is not allowed");
240  assert(VarIter != 0 && "Iterator has invalid value of VarIter member");
241  return Scope->Vars[0];
242  }
243 
244  VarDecl *operator*() const {
245  return *this->operator->();
246  }
247 
248  const_iterator &operator++() {
249  if (!Scope)
250  return *this;
251 
252  assert(VarIter != 0 && "Iterator has invalid value of VarIter member");
253  --VarIter;
254  if (VarIter == 0)
255  *this = Scope->Prev;
256  return *this;
257  }
258  const_iterator operator++(int) {
259  const_iterator P = *this;
260  ++*this;
261  return P;
262  }
263 
264  bool operator==(const const_iterator &rhs) const {
265  return Scope == rhs.Scope && VarIter == rhs.VarIter;
266  }
267  bool operator!=(const const_iterator &rhs) const {
268  return !(*this == rhs);
269  }
270 
271  explicit operator bool() const {
272  return *this != const_iterator();
273  }
274 
275  int distance(const_iterator L);
276  const_iterator shared_parent(const_iterator L);
277  bool pointsToFirstDeclaredVar() { return VarIter == 1; }
278  };
279 
280 private:
281  BumpVectorContext ctx;
282 
283  /// Automatic variables in order of declaration.
284  AutomaticVarsTy Vars;
285 
286  /// Iterator to variable in previous scope that was declared just before
287  /// begin of this scope.
288  const_iterator Prev;
289 
290 public:
291  /// Constructs empty scope linked to previous scope in specified place.
292  LocalScope(BumpVectorContext ctx, const_iterator P)
293  : ctx(std::move(ctx)), Vars(this->ctx, 4), Prev(P) {}
294 
295  /// Begin of scope in direction of CFG building (backwards).
296  const_iterator begin() const { return const_iterator(*this, Vars.size()); }
297 
298  void addVar(VarDecl *VD) {
299  Vars.push_back(VD, ctx);
300  }
301 };
302 
303 } // namespace
304 
305 /// distance - Calculates distance from this to L. L must be reachable from this
306 /// (with use of ++ operator). Cost of calculating the distance is linear w.r.t.
307 /// number of scopes between this and L.
308 int LocalScope::const_iterator::distance(LocalScope::const_iterator L) {
309  int D = 0;
310  const_iterator F = *this;
311  while (F.Scope != L.Scope) {
312  assert(F != const_iterator() &&
313  "L iterator is not reachable from F iterator.");
314  D += F.VarIter;
315  F = F.Scope->Prev;
316  }
317  D += F.VarIter - L.VarIter;
318  return D;
319 }
320 
321 /// Calculates the closest parent of this iterator
322 /// that is in a scope reachable through the parents of L.
323 /// I.e. when using 'goto' from this to L, the lifetime of all variables
324 /// between this and shared_parent(L) end.
325 LocalScope::const_iterator
326 LocalScope::const_iterator::shared_parent(LocalScope::const_iterator L) {
327  llvm::SmallPtrSet<const LocalScope *, 4> ScopesOfL;
328  while (true) {
329  ScopesOfL.insert(L.Scope);
330  if (L == const_iterator())
331  break;
332  L = L.Scope->Prev;
333  }
334 
335  const_iterator F = *this;
336  while (true) {
337  if (ScopesOfL.count(F.Scope))
338  return F;
339  assert(F != const_iterator() &&
340  "L iterator is not reachable from F iterator.");
341  F = F.Scope->Prev;
342  }
343 }
344 
345 namespace {
346 
347 /// Structure for specifying position in CFG during its build process. It
348 /// consists of CFGBlock that specifies position in CFG and
349 /// LocalScope::const_iterator that specifies position in LocalScope graph.
350 struct BlockScopePosPair {
351  CFGBlock *block = nullptr;
352  LocalScope::const_iterator scopePosition;
353 
354  BlockScopePosPair() = default;
355  BlockScopePosPair(CFGBlock *b, LocalScope::const_iterator scopePos)
356  : block(b), scopePosition(scopePos) {}
357 };
358 
359 /// TryResult - a class representing a variant over the values
360 /// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool,
361 /// and is used by the CFGBuilder to decide if a branch condition
362 /// can be decided up front during CFG construction.
363 class TryResult {
364  int X = -1;
365 
366 public:
367  TryResult() = default;
368  TryResult(bool b) : X(b ? 1 : 0) {}
369 
370  bool isTrue() const { return X == 1; }
371  bool isFalse() const { return X == 0; }
372  bool isKnown() const { return X >= 0; }
373 
374  void negate() {
375  assert(isKnown());
376  X ^= 0x1;
377  }
378 };
379 
380 } // namespace
381 
382 static TryResult bothKnownTrue(TryResult R1, TryResult R2) {
383  if (!R1.isKnown() || !R2.isKnown())
384  return TryResult();
385  return TryResult(R1.isTrue() && R2.isTrue());
386 }
387 
388 namespace {
389 
390 class reverse_children {
391  llvm::SmallVector<Stmt *, 12> childrenBuf;
393 
394 public:
395  reverse_children(Stmt *S);
396 
397  using iterator = ArrayRef<Stmt *>::reverse_iterator;
398 
399  iterator begin() const { return children.rbegin(); }
400  iterator end() const { return children.rend(); }
401 };
402 
403 } // namespace
404 
405 reverse_children::reverse_children(Stmt *S) {
406  if (CallExpr *CE = dyn_cast<CallExpr>(S)) {
407  children = CE->getRawSubExprs();
408  return;
409  }
410  switch (S->getStmtClass()) {
411  // Note: Fill in this switch with more cases we want to optimize.
412  case Stmt::InitListExprClass: {
413  InitListExpr *IE = cast<InitListExpr>(S);
414  children = llvm::makeArrayRef(reinterpret_cast<Stmt**>(IE->getInits()),
415  IE->getNumInits());
416  return;
417  }
418  default:
419  break;
420  }
421 
422  // Default case for all other statements.
423  for (Stmt *SubStmt : S->children())
424  childrenBuf.push_back(SubStmt);
425 
426  // This needs to be done *after* childrenBuf has been populated.
427  children = childrenBuf;
428 }
429 
430 namespace {
431 
432 /// CFGBuilder - This class implements CFG construction from an AST.
433 /// The builder is stateful: an instance of the builder should be used to only
434 /// construct a single CFG.
435 ///
436 /// Example usage:
437 ///
438 /// CFGBuilder builder;
439 /// std::unique_ptr<CFG> cfg = builder.buildCFG(decl, stmt1);
440 ///
441 /// CFG construction is done via a recursive walk of an AST. We actually parse
442 /// the AST in reverse order so that the successor of a basic block is
443 /// constructed prior to its predecessor. This allows us to nicely capture
444 /// implicit fall-throughs without extra basic blocks.
445 class CFGBuilder {
446  using JumpTarget = BlockScopePosPair;
447  using JumpSource = BlockScopePosPair;
448 
449  ASTContext *Context;
450  std::unique_ptr<CFG> cfg;
451 
452  // Current block.
453  CFGBlock *Block = nullptr;
454 
455  // Block after the current block.
456  CFGBlock *Succ = nullptr;
457 
458  JumpTarget ContinueJumpTarget;
459  JumpTarget BreakJumpTarget;
460  JumpTarget SEHLeaveJumpTarget;
461  CFGBlock *SwitchTerminatedBlock = nullptr;
462  CFGBlock *DefaultCaseBlock = nullptr;
463 
464  // This can point either to a try or a __try block. The frontend forbids
465  // mixing both kinds in one function, so having one for both is enough.
466  CFGBlock *TryTerminatedBlock = nullptr;
467 
468  // Current position in local scope.
469  LocalScope::const_iterator ScopePos;
470 
471  // LabelMap records the mapping from Label expressions to their jump targets.
472  using LabelMapTy = llvm::DenseMap<LabelDecl *, JumpTarget>;
473  LabelMapTy LabelMap;
474 
475  // A list of blocks that end with a "goto" that must be backpatched to their
476  // resolved targets upon completion of CFG construction.
477  using BackpatchBlocksTy = std::vector<JumpSource>;
478  BackpatchBlocksTy BackpatchBlocks;
479 
480  // A list of labels whose address has been taken (for indirect gotos).
481  using LabelSetTy = llvm::SmallSetVector<LabelDecl *, 8>;
482  LabelSetTy AddressTakenLabels;
483 
484  // Information about the currently visited C++ object construction site.
485  // This is set in the construction trigger and read when the constructor
486  // or a function that returns an object by value is being visited.
487  llvm::DenseMap<Expr *, const ConstructionContextLayer *>
488  ConstructionContextMap;
489 
490  using DeclsWithEndedScopeSetTy = llvm::SmallSetVector<VarDecl *, 16>;
491  DeclsWithEndedScopeSetTy DeclsWithEndedScope;
492 
493  bool badCFG = false;
494  const CFG::BuildOptions &BuildOpts;
495 
496  // State to track for building switch statements.
497  bool switchExclusivelyCovered = false;
498  Expr::EvalResult *switchCond = nullptr;
499 
500  CFG::BuildOptions::ForcedBlkExprs::value_type *cachedEntry = nullptr;
501  const Stmt *lastLookup = nullptr;
502 
503  // Caches boolean evaluations of expressions to avoid multiple re-evaluations
504  // during construction of branches for chained logical operators.
505  using CachedBoolEvalsTy = llvm::DenseMap<Expr *, TryResult>;
506  CachedBoolEvalsTy CachedBoolEvals;
507 
508 public:
509  explicit CFGBuilder(ASTContext *astContext,
510  const CFG::BuildOptions &buildOpts)
511  : Context(astContext), cfg(new CFG()), // crew a new CFG
512  ConstructionContextMap(), BuildOpts(buildOpts) {}
513 
514 
515  // buildCFG - Used by external clients to construct the CFG.
516  std::unique_ptr<CFG> buildCFG(const Decl *D, Stmt *Statement);
517 
518  bool alwaysAdd(const Stmt *stmt);
519 
520 private:
521  // Visitors to walk an AST and construct the CFG.
522  CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc);
523  CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc);
524  CFGBlock *VisitBreakStmt(BreakStmt *B);
525  CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc);
526  CFGBlock *VisitCaseStmt(CaseStmt *C);
527  CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc);
528  CFGBlock *VisitCompoundStmt(CompoundStmt *C);
529  CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C,
530  AddStmtChoice asc);
531  CFGBlock *VisitContinueStmt(ContinueStmt *C);
532  CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
533  AddStmtChoice asc);
534  CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S);
535  CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc);
536  CFGBlock *VisitCXXNewExpr(CXXNewExpr *DE, AddStmtChoice asc);
537  CFGBlock *VisitCXXDeleteExpr(CXXDeleteExpr *DE, AddStmtChoice asc);
538  CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S);
539  CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
540  AddStmtChoice asc);
541  CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
542  AddStmtChoice asc);
543  CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T);
544  CFGBlock *VisitCXXTryStmt(CXXTryStmt *S);
545  CFGBlock *VisitDeclStmt(DeclStmt *DS);
546  CFGBlock *VisitDeclSubExpr(DeclStmt *DS);
547  CFGBlock *VisitDefaultStmt(DefaultStmt *D);
548  CFGBlock *VisitDoStmt(DoStmt *D);
549  CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, AddStmtChoice asc);
550  CFGBlock *VisitForStmt(ForStmt *F);
551  CFGBlock *VisitGotoStmt(GotoStmt *G);
552  CFGBlock *VisitIfStmt(IfStmt *I);
553  CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc);
554  CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I);
555  CFGBlock *VisitLabelStmt(LabelStmt *L);
556  CFGBlock *VisitBlockExpr(BlockExpr *E, AddStmtChoice asc);
557  CFGBlock *VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc);
558  CFGBlock *VisitLogicalOperator(BinaryOperator *B);
559  std::pair<CFGBlock *, CFGBlock *> VisitLogicalOperator(BinaryOperator *B,
560  Stmt *Term,
561  CFGBlock *TrueBlock,
562  CFGBlock *FalseBlock);
563  CFGBlock *VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *MTE,
564  AddStmtChoice asc);
565  CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc);
566  CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S);
567  CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S);
568  CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S);
569  CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S);
570  CFGBlock *VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S);
571  CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S);
572  CFGBlock *VisitObjCMessageExpr(ObjCMessageExpr *E, AddStmtChoice asc);
573  CFGBlock *VisitPseudoObjectExpr(PseudoObjectExpr *E);
574  CFGBlock *VisitReturnStmt(ReturnStmt *R);
575  CFGBlock *VisitSEHExceptStmt(SEHExceptStmt *S);
576  CFGBlock *VisitSEHFinallyStmt(SEHFinallyStmt *S);
577  CFGBlock *VisitSEHLeaveStmt(SEHLeaveStmt *S);
578  CFGBlock *VisitSEHTryStmt(SEHTryStmt *S);
579  CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc);
580  CFGBlock *VisitSwitchStmt(SwitchStmt *S);
581  CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
582  AddStmtChoice asc);
583  CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc);
584  CFGBlock *VisitWhileStmt(WhileStmt *W);
585 
586  CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd);
587  CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc);
588  CFGBlock *VisitChildren(Stmt *S);
589  CFGBlock *VisitNoRecurse(Expr *E, AddStmtChoice asc);
590 
591  void maybeAddScopeBeginForVarDecl(CFGBlock *B, const VarDecl *VD,
592  const Stmt *S) {
593  if (ScopePos && (VD == ScopePos.getFirstVarInScope()))
594  appendScopeBegin(B, VD, S);
595  }
596 
597  /// When creating the CFG for temporary destructors, we want to mirror the
598  /// branch structure of the corresponding constructor calls.
599  /// Thus, while visiting a statement for temporary destructors, we keep a
600  /// context to keep track of the following information:
601  /// - whether a subexpression is executed unconditionally
602  /// - if a subexpression is executed conditionally, the first
603  /// CXXBindTemporaryExpr we encounter in that subexpression (which
604  /// corresponds to the last temporary destructor we have to call for this
605  /// subexpression) and the CFG block at that point (which will become the
606  /// successor block when inserting the decision point).
607  ///
608  /// That way, we can build the branch structure for temporary destructors as
609  /// follows:
610  /// 1. If a subexpression is executed unconditionally, we add the temporary
611  /// destructor calls to the current block.
612  /// 2. If a subexpression is executed conditionally, when we encounter a
613  /// CXXBindTemporaryExpr:
614  /// a) If it is the first temporary destructor call in the subexpression,
615  /// we remember the CXXBindTemporaryExpr and the current block in the
616  /// TempDtorContext; we start a new block, and insert the temporary
617  /// destructor call.
618  /// b) Otherwise, add the temporary destructor call to the current block.
619  /// 3. When we finished visiting a conditionally executed subexpression,
620  /// and we found at least one temporary constructor during the visitation
621  /// (2.a has executed), we insert a decision block that uses the
622  /// CXXBindTemporaryExpr as terminator, and branches to the current block
623  /// if the CXXBindTemporaryExpr was marked executed, and otherwise
624  /// branches to the stored successor.
625  struct TempDtorContext {
626  TempDtorContext() = default;
627  TempDtorContext(TryResult KnownExecuted)
628  : IsConditional(true), KnownExecuted(KnownExecuted) {}
629 
630  /// Returns whether we need to start a new branch for a temporary destructor
631  /// call. This is the case when the temporary destructor is
632  /// conditionally executed, and it is the first one we encounter while
633  /// visiting a subexpression - other temporary destructors at the same level
634  /// will be added to the same block and are executed under the same
635  /// condition.
636  bool needsTempDtorBranch() const {
637  return IsConditional && !TerminatorExpr;
638  }
639 
640  /// Remember the successor S of a temporary destructor decision branch for
641  /// the corresponding CXXBindTemporaryExpr E.
642  void setDecisionPoint(CFGBlock *S, CXXBindTemporaryExpr *E) {
643  Succ = S;
644  TerminatorExpr = E;
645  }
646 
647  const bool IsConditional = false;
648  const TryResult KnownExecuted = true;
649  CFGBlock *Succ = nullptr;
650  CXXBindTemporaryExpr *TerminatorExpr = nullptr;
651  };
652 
653  // Visitors to walk an AST and generate destructors of temporaries in
654  // full expression.
655  CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary,
656  TempDtorContext &Context);
657  CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E, TempDtorContext &Context);
658  CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E,
659  TempDtorContext &Context);
660  CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(
661  CXXBindTemporaryExpr *E, bool BindToTemporary, TempDtorContext &Context);
662  CFGBlock *VisitConditionalOperatorForTemporaryDtors(
663  AbstractConditionalOperator *E, bool BindToTemporary,
664  TempDtorContext &Context);
665  void InsertTempDtorDecisionBlock(const TempDtorContext &Context,
666  CFGBlock *FalseSucc = nullptr);
667 
668  // NYS == Not Yet Supported
669  CFGBlock *NYS() {
670  badCFG = true;
671  return Block;
672  }
673 
674  // Remember to apply the construction context based on the current \p Layer
675  // when constructing the CFG element for \p CE.
676  void consumeConstructionContext(const ConstructionContextLayer *Layer,
677  Expr *E);
678 
679  // Scan \p Child statement to find constructors in it, while keeping in mind
680  // that its parent statement is providing a partial construction context
681  // described by \p Layer. If a constructor is found, it would be assigned
682  // the context based on the layer. If an additional construction context layer
683  // is found, the function recurses into that.
684  void findConstructionContexts(const ConstructionContextLayer *Layer,
685  Stmt *Child);
686 
687  // Scan all arguments of a call expression for a construction context.
688  // These sorts of call expressions don't have a common superclass,
689  // hence strict duck-typing.
690  template <typename CallLikeExpr,
691  typename = typename std::enable_if<
692  std::is_same<CallLikeExpr, CallExpr>::value ||
693  std::is_same<CallLikeExpr, CXXConstructExpr>::value ||
694  std::is_same<CallLikeExpr, ObjCMessageExpr>::value>>
695  void findConstructionContextsForArguments(CallLikeExpr *E) {
696  for (unsigned i = 0, e = E->getNumArgs(); i != e; ++i) {
697  Expr *Arg = E->getArg(i);
698  if (Arg->getType()->getAsCXXRecordDecl() && !Arg->isGLValue())
699  findConstructionContexts(
700  ConstructionContextLayer::create(cfg->getBumpVectorContext(),
702  Arg);
703  }
704  }
705 
706  // Unset the construction context after consuming it. This is done immediately
707  // after adding the CFGConstructor or CFGCXXRecordTypedCall element, so
708  // there's no need to do this manually in every Visit... function.
709  void cleanupConstructionContext(Expr *E);
710 
711  void autoCreateBlock() { if (!Block) Block = createBlock(); }
712  CFGBlock *createBlock(bool add_successor = true);
713  CFGBlock *createNoReturnBlock();
714 
715  CFGBlock *addStmt(Stmt *S) {
716  return Visit(S, AddStmtChoice::AlwaysAdd);
717  }
718 
719  CFGBlock *addInitializer(CXXCtorInitializer *I);
720  void addLoopExit(const Stmt *LoopStmt);
721  void addAutomaticObjDtors(LocalScope::const_iterator B,
722  LocalScope::const_iterator E, Stmt *S);
723  void addLifetimeEnds(LocalScope::const_iterator B,
724  LocalScope::const_iterator E, Stmt *S);
725  void addAutomaticObjHandling(LocalScope::const_iterator B,
726  LocalScope::const_iterator E, Stmt *S);
727  void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD);
728  void addScopesEnd(LocalScope::const_iterator B, LocalScope::const_iterator E,
729  Stmt *S);
730 
731  void getDeclsWithEndedScope(LocalScope::const_iterator B,
732  LocalScope::const_iterator E, Stmt *S);
733 
734  // Local scopes creation.
735  LocalScope* createOrReuseLocalScope(LocalScope* Scope);
736 
737  void addLocalScopeForStmt(Stmt *S);
738  LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS,
739  LocalScope* Scope = nullptr);
740  LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = nullptr);
741 
742  void addLocalScopeAndDtors(Stmt *S);
743 
744  const ConstructionContext *retrieveAndCleanupConstructionContext(Expr *E) {
745  if (!BuildOpts.AddRichCXXConstructors)
746  return nullptr;
747 
748  const ConstructionContextLayer *Layer = ConstructionContextMap.lookup(E);
749  if (!Layer)
750  return nullptr;
751 
752  cleanupConstructionContext(E);
753  return ConstructionContext::createFromLayers(cfg->getBumpVectorContext(),
754  Layer);
755  }
756 
757  // Interface to CFGBlock - adding CFGElements.
758 
759  void appendStmt(CFGBlock *B, const Stmt *S) {
760  if (alwaysAdd(S) && cachedEntry)
761  cachedEntry->second = B;
762 
763  // All block-level expressions should have already been IgnoreParens()ed.
764  assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S);
765  B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext());
766  }
767 
768  void appendConstructor(CFGBlock *B, CXXConstructExpr *CE) {
769  if (const ConstructionContext *CC =
770  retrieveAndCleanupConstructionContext(CE)) {
771  B->appendConstructor(CE, CC, cfg->getBumpVectorContext());
772  return;
773  }
774 
775  // No valid construction context found. Fall back to statement.
776  B->appendStmt(CE, cfg->getBumpVectorContext());
777  }
778 
779  void appendCall(CFGBlock *B, CallExpr *CE) {
780  if (alwaysAdd(CE) && cachedEntry)
781  cachedEntry->second = B;
782 
783  if (const ConstructionContext *CC =
784  retrieveAndCleanupConstructionContext(CE)) {
785  B->appendCXXRecordTypedCall(CE, CC, cfg->getBumpVectorContext());
786  return;
787  }
788 
789  // No valid construction context found. Fall back to statement.
790  B->appendStmt(CE, cfg->getBumpVectorContext());
791  }
792 
793  void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) {
794  B->appendInitializer(I, cfg->getBumpVectorContext());
795  }
796 
797  void appendNewAllocator(CFGBlock *B, CXXNewExpr *NE) {
798  B->appendNewAllocator(NE, cfg->getBumpVectorContext());
799  }
800 
801  void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) {
802  B->appendBaseDtor(BS, cfg->getBumpVectorContext());
803  }
804 
805  void appendMemberDtor(CFGBlock *B, FieldDecl *FD) {
806  B->appendMemberDtor(FD, cfg->getBumpVectorContext());
807  }
808 
809  void appendObjCMessage(CFGBlock *B, ObjCMessageExpr *ME) {
810  if (alwaysAdd(ME) && cachedEntry)
811  cachedEntry->second = B;
812 
813  if (const ConstructionContext *CC =
814  retrieveAndCleanupConstructionContext(ME)) {
815  B->appendCXXRecordTypedCall(ME, CC, cfg->getBumpVectorContext());
816  return;
817  }
818 
819  B->appendStmt(const_cast<ObjCMessageExpr *>(ME),
820  cfg->getBumpVectorContext());
821  }
822 
823  void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) {
824  B->appendTemporaryDtor(E, cfg->getBumpVectorContext());
825  }
826 
827  void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) {
828  B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext());
829  }
830 
831  void appendLifetimeEnds(CFGBlock *B, VarDecl *VD, Stmt *S) {
832  B->appendLifetimeEnds(VD, S, cfg->getBumpVectorContext());
833  }
834 
835  void appendLoopExit(CFGBlock *B, const Stmt *LoopStmt) {
836  B->appendLoopExit(LoopStmt, cfg->getBumpVectorContext());
837  }
838 
839  void appendDeleteDtor(CFGBlock *B, CXXRecordDecl *RD, CXXDeleteExpr *DE) {
840  B->appendDeleteDtor(RD, DE, cfg->getBumpVectorContext());
841  }
842 
843  void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
844  LocalScope::const_iterator B, LocalScope::const_iterator E);
845 
846  void prependAutomaticObjLifetimeWithTerminator(CFGBlock *Blk,
847  LocalScope::const_iterator B,
848  LocalScope::const_iterator E);
849 
850  const VarDecl *
851  prependAutomaticObjScopeEndWithTerminator(CFGBlock *Blk,
852  LocalScope::const_iterator B,
853  LocalScope::const_iterator E);
854 
855  void addSuccessor(CFGBlock *B, CFGBlock *S, bool IsReachable = true) {
856  B->addSuccessor(CFGBlock::AdjacentBlock(S, IsReachable),
857  cfg->getBumpVectorContext());
858  }
859 
860  /// Add a reachable successor to a block, with the alternate variant that is
861  /// unreachable.
862  void addSuccessor(CFGBlock *B, CFGBlock *ReachableBlock, CFGBlock *AltBlock) {
863  B->addSuccessor(CFGBlock::AdjacentBlock(ReachableBlock, AltBlock),
864  cfg->getBumpVectorContext());
865  }
866 
867  void appendScopeBegin(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
868  if (BuildOpts.AddScopes)
869  B->appendScopeBegin(VD, S, cfg->getBumpVectorContext());
870  }
871 
872  void prependScopeBegin(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
873  if (BuildOpts.AddScopes)
874  B->prependScopeBegin(VD, S, cfg->getBumpVectorContext());
875  }
876 
877  void appendScopeEnd(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
878  if (BuildOpts.AddScopes)
879  B->appendScopeEnd(VD, S, cfg->getBumpVectorContext());
880  }
881 
882  void prependScopeEnd(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
883  if (BuildOpts.AddScopes)
884  B->prependScopeEnd(VD, S, cfg->getBumpVectorContext());
885  }
886 
887  /// Find a relational comparison with an expression evaluating to a
888  /// boolean and a constant other than 0 and 1.
889  /// e.g. if ((x < y) == 10)
890  TryResult checkIncorrectRelationalOperator(const BinaryOperator *B) {
891  const Expr *LHSExpr = B->getLHS()->IgnoreParens();
892  const Expr *RHSExpr = B->getRHS()->IgnoreParens();
893 
894  const IntegerLiteral *IntLiteral = dyn_cast<IntegerLiteral>(LHSExpr);
895  const Expr *BoolExpr = RHSExpr;
896  bool IntFirst = true;
897  if (!IntLiteral) {
898  IntLiteral = dyn_cast<IntegerLiteral>(RHSExpr);
899  BoolExpr = LHSExpr;
900  IntFirst = false;
901  }
902 
903  if (!IntLiteral || !BoolExpr->isKnownToHaveBooleanValue())
904  return TryResult();
905 
906  llvm::APInt IntValue = IntLiteral->getValue();
907  if ((IntValue == 1) || (IntValue == 0))
908  return TryResult();
909 
910  bool IntLarger = IntLiteral->getType()->isUnsignedIntegerType() ||
911  !IntValue.isNegative();
912 
913  BinaryOperatorKind Bok = B->getOpcode();
914  if (Bok == BO_GT || Bok == BO_GE) {
915  // Always true for 10 > bool and bool > -1
916  // Always false for -1 > bool and bool > 10
917  return TryResult(IntFirst == IntLarger);
918  } else {
919  // Always true for -1 < bool and bool < 10
920  // Always false for 10 < bool and bool < -1
921  return TryResult(IntFirst != IntLarger);
922  }
923  }
924 
925  /// Find an incorrect equality comparison. Either with an expression
926  /// evaluating to a boolean and a constant other than 0 and 1.
927  /// e.g. if (!x == 10) or a bitwise and/or operation that always evaluates to
928  /// true/false e.q. (x & 8) == 4.
929  TryResult checkIncorrectEqualityOperator(const BinaryOperator *B) {
930  const Expr *LHSExpr = B->getLHS()->IgnoreParens();
931  const Expr *RHSExpr = B->getRHS()->IgnoreParens();
932 
933  const IntegerLiteral *IntLiteral = dyn_cast<IntegerLiteral>(LHSExpr);
934  const Expr *BoolExpr = RHSExpr;
935 
936  if (!IntLiteral) {
937  IntLiteral = dyn_cast<IntegerLiteral>(RHSExpr);
938  BoolExpr = LHSExpr;
939  }
940 
941  if (!IntLiteral)
942  return TryResult();
943 
944  const BinaryOperator *BitOp = dyn_cast<BinaryOperator>(BoolExpr);
945  if (BitOp && (BitOp->getOpcode() == BO_And ||
946  BitOp->getOpcode() == BO_Or)) {
947  const Expr *LHSExpr2 = BitOp->getLHS()->IgnoreParens();
948  const Expr *RHSExpr2 = BitOp->getRHS()->IgnoreParens();
949 
950  const IntegerLiteral *IntLiteral2 = dyn_cast<IntegerLiteral>(LHSExpr2);
951 
952  if (!IntLiteral2)
953  IntLiteral2 = dyn_cast<IntegerLiteral>(RHSExpr2);
954 
955  if (!IntLiteral2)
956  return TryResult();
957 
958  llvm::APInt L1 = IntLiteral->getValue();
959  llvm::APInt L2 = IntLiteral2->getValue();
960  if ((BitOp->getOpcode() == BO_And && (L2 & L1) != L1) ||
961  (BitOp->getOpcode() == BO_Or && (L2 | L1) != L1)) {
962  if (BuildOpts.Observer)
963  BuildOpts.Observer->compareBitwiseEquality(B,
964  B->getOpcode() != BO_EQ);
965  TryResult(B->getOpcode() != BO_EQ);
966  }
967  } else if (BoolExpr->isKnownToHaveBooleanValue()) {
968  llvm::APInt IntValue = IntLiteral->getValue();
969  if ((IntValue == 1) || (IntValue == 0)) {
970  return TryResult();
971  }
972  return TryResult(B->getOpcode() != BO_EQ);
973  }
974 
975  return TryResult();
976  }
977 
978  TryResult analyzeLogicOperatorCondition(BinaryOperatorKind Relation,
979  const llvm::APSInt &Value1,
980  const llvm::APSInt &Value2) {
981  assert(Value1.isSigned() == Value2.isSigned());
982  switch (Relation) {
983  default:
984  return TryResult();
985  case BO_EQ:
986  return TryResult(Value1 == Value2);
987  case BO_NE:
988  return TryResult(Value1 != Value2);
989  case BO_LT:
990  return TryResult(Value1 < Value2);
991  case BO_LE:
992  return TryResult(Value1 <= Value2);
993  case BO_GT:
994  return TryResult(Value1 > Value2);
995  case BO_GE:
996  return TryResult(Value1 >= Value2);
997  }
998  }
999 
1000  /// Find a pair of comparison expressions with or without parentheses
1001  /// with a shared variable and constants and a logical operator between them
1002  /// that always evaluates to either true or false.
1003  /// e.g. if (x != 3 || x != 4)
1004  TryResult checkIncorrectLogicOperator(const BinaryOperator *B) {
1005  assert(B->isLogicalOp());
1006  const BinaryOperator *LHS =
1007  dyn_cast<BinaryOperator>(B->getLHS()->IgnoreParens());
1008  const BinaryOperator *RHS =
1009  dyn_cast<BinaryOperator>(B->getRHS()->IgnoreParens());
1010  if (!LHS || !RHS)
1011  return {};
1012 
1013  if (!LHS->isComparisonOp() || !RHS->isComparisonOp())
1014  return {};
1015 
1016  const DeclRefExpr *Decl1;
1017  const Expr *Expr1;
1018  BinaryOperatorKind BO1;
1019  std::tie(Decl1, BO1, Expr1) = tryNormalizeBinaryOperator(LHS);
1020 
1021  if (!Decl1 || !Expr1)
1022  return {};
1023 
1024  const DeclRefExpr *Decl2;
1025  const Expr *Expr2;
1026  BinaryOperatorKind BO2;
1027  std::tie(Decl2, BO2, Expr2) = tryNormalizeBinaryOperator(RHS);
1028 
1029  if (!Decl2 || !Expr2)
1030  return {};
1031 
1032  // Check that it is the same variable on both sides.
1033  if (Decl1->getDecl() != Decl2->getDecl())
1034  return {};
1035 
1036  // Make sure the user's intent is clear (e.g. they're comparing against two
1037  // int literals, or two things from the same enum)
1038  if (!areExprTypesCompatible(Expr1, Expr2))
1039  return {};
1040 
1041  llvm::APSInt L1, L2;
1042 
1043  if (!Expr1->EvaluateAsInt(L1, *Context) ||
1044  !Expr2->EvaluateAsInt(L2, *Context))
1045  return {};
1046 
1047  // Can't compare signed with unsigned or with different bit width.
1048  if (L1.isSigned() != L2.isSigned() || L1.getBitWidth() != L2.getBitWidth())
1049  return {};
1050 
1051  // Values that will be used to determine if result of logical
1052  // operator is always true/false
1053  const llvm::APSInt Values[] = {
1054  // Value less than both Value1 and Value2
1055  llvm::APSInt::getMinValue(L1.getBitWidth(), L1.isUnsigned()),
1056  // L1
1057  L1,
1058  // Value between Value1 and Value2
1059  ((L1 < L2) ? L1 : L2) + llvm::APSInt(llvm::APInt(L1.getBitWidth(), 1),
1060  L1.isUnsigned()),
1061  // L2
1062  L2,
1063  // Value greater than both Value1 and Value2
1064  llvm::APSInt::getMaxValue(L1.getBitWidth(), L1.isUnsigned()),
1065  };
1066 
1067  // Check whether expression is always true/false by evaluating the following
1068  // * variable x is less than the smallest literal.
1069  // * variable x is equal to the smallest literal.
1070  // * Variable x is between smallest and largest literal.
1071  // * Variable x is equal to the largest literal.
1072  // * Variable x is greater than largest literal.
1073  bool AlwaysTrue = true, AlwaysFalse = true;
1074  for (const llvm::APSInt &Value : Values) {
1075  TryResult Res1, Res2;
1076  Res1 = analyzeLogicOperatorCondition(BO1, Value, L1);
1077  Res2 = analyzeLogicOperatorCondition(BO2, Value, L2);
1078 
1079  if (!Res1.isKnown() || !Res2.isKnown())
1080  return {};
1081 
1082  if (B->getOpcode() == BO_LAnd) {
1083  AlwaysTrue &= (Res1.isTrue() && Res2.isTrue());
1084  AlwaysFalse &= !(Res1.isTrue() && Res2.isTrue());
1085  } else {
1086  AlwaysTrue &= (Res1.isTrue() || Res2.isTrue());
1087  AlwaysFalse &= !(Res1.isTrue() || Res2.isTrue());
1088  }
1089  }
1090 
1091  if (AlwaysTrue || AlwaysFalse) {
1092  if (BuildOpts.Observer)
1093  BuildOpts.Observer->compareAlwaysTrue(B, AlwaysTrue);
1094  return TryResult(AlwaysTrue);
1095  }
1096  return {};
1097  }
1098 
1099  /// Try and evaluate an expression to an integer constant.
1100  bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) {
1101  if (!BuildOpts.PruneTriviallyFalseEdges)
1102  return false;
1103  return !S->isTypeDependent() &&
1104  !S->isValueDependent() &&
1105  S->EvaluateAsRValue(outResult, *Context);
1106  }
1107 
1108  /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1
1109  /// if we can evaluate to a known value, otherwise return -1.
1110  TryResult tryEvaluateBool(Expr *S) {
1111  if (!BuildOpts.PruneTriviallyFalseEdges ||
1112  S->isTypeDependent() || S->isValueDependent())
1113  return {};
1114 
1115  if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(S)) {
1116  if (Bop->isLogicalOp()) {
1117  // Check the cache first.
1118  CachedBoolEvalsTy::iterator I = CachedBoolEvals.find(S);
1119  if (I != CachedBoolEvals.end())
1120  return I->second; // already in map;
1121 
1122  // Retrieve result at first, or the map might be updated.
1123  TryResult Result = evaluateAsBooleanConditionNoCache(S);
1124  CachedBoolEvals[S] = Result; // update or insert
1125  return Result;
1126  }
1127  else {
1128  switch (Bop->getOpcode()) {
1129  default: break;
1130  // For 'x & 0' and 'x * 0', we can determine that
1131  // the value is always false.
1132  case BO_Mul:
1133  case BO_And: {
1134  // If either operand is zero, we know the value
1135  // must be false.
1136  llvm::APSInt IntVal;
1137  if (Bop->getLHS()->EvaluateAsInt(IntVal, *Context)) {
1138  if (!IntVal.getBoolValue()) {
1139  return TryResult(false);
1140  }
1141  }
1142  if (Bop->getRHS()->EvaluateAsInt(IntVal, *Context)) {
1143  if (!IntVal.getBoolValue()) {
1144  return TryResult(false);
1145  }
1146  }
1147  }
1148  break;
1149  }
1150  }
1151  }
1152 
1153  return evaluateAsBooleanConditionNoCache(S);
1154  }
1155 
1156  /// Evaluate as boolean \param E without using the cache.
1157  TryResult evaluateAsBooleanConditionNoCache(Expr *E) {
1158  if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(E)) {
1159  if (Bop->isLogicalOp()) {
1160  TryResult LHS = tryEvaluateBool(Bop->getLHS());
1161  if (LHS.isKnown()) {
1162  // We were able to evaluate the LHS, see if we can get away with not
1163  // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
1164  if (LHS.isTrue() == (Bop->getOpcode() == BO_LOr))
1165  return LHS.isTrue();
1166 
1167  TryResult RHS = tryEvaluateBool(Bop->getRHS());
1168  if (RHS.isKnown()) {
1169  if (Bop->getOpcode() == BO_LOr)
1170  return LHS.isTrue() || RHS.isTrue();
1171  else
1172  return LHS.isTrue() && RHS.isTrue();
1173  }
1174  } else {
1175  TryResult RHS = tryEvaluateBool(Bop->getRHS());
1176  if (RHS.isKnown()) {
1177  // We can't evaluate the LHS; however, sometimes the result
1178  // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
1179  if (RHS.isTrue() == (Bop->getOpcode() == BO_LOr))
1180  return RHS.isTrue();
1181  } else {
1182  TryResult BopRes = checkIncorrectLogicOperator(Bop);
1183  if (BopRes.isKnown())
1184  return BopRes.isTrue();
1185  }
1186  }
1187 
1188  return {};
1189  } else if (Bop->isEqualityOp()) {
1190  TryResult BopRes = checkIncorrectEqualityOperator(Bop);
1191  if (BopRes.isKnown())
1192  return BopRes.isTrue();
1193  } else if (Bop->isRelationalOp()) {
1194  TryResult BopRes = checkIncorrectRelationalOperator(Bop);
1195  if (BopRes.isKnown())
1196  return BopRes.isTrue();
1197  }
1198  }
1199 
1200  bool Result;
1201  if (E->EvaluateAsBooleanCondition(Result, *Context))
1202  return Result;
1203 
1204  return {};
1205  }
1206 
1207  bool hasTrivialDestructor(VarDecl *VD);
1208 };
1209 
1210 } // namespace
1211 
1212 inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder,
1213  const Stmt *stmt) const {
1214  return builder.alwaysAdd(stmt) || kind == AlwaysAdd;
1215 }
1216 
1217 bool CFGBuilder::alwaysAdd(const Stmt *stmt) {
1218  bool shouldAdd = BuildOpts.alwaysAdd(stmt);
1219 
1220  if (!BuildOpts.forcedBlkExprs)
1221  return shouldAdd;
1222 
1223  if (lastLookup == stmt) {
1224  if (cachedEntry) {
1225  assert(cachedEntry->first == stmt);
1226  return true;
1227  }
1228  return shouldAdd;
1229  }
1230 
1231  lastLookup = stmt;
1232 
1233  // Perform the lookup!
1234  CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs;
1235 
1236  if (!fb) {
1237  // No need to update 'cachedEntry', since it will always be null.
1238  assert(!cachedEntry);
1239  return shouldAdd;
1240  }
1241 
1242  CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt);
1243  if (itr == fb->end()) {
1244  cachedEntry = nullptr;
1245  return shouldAdd;
1246  }
1247 
1248  cachedEntry = &*itr;
1249  return true;
1250 }
1251 
1252 // FIXME: Add support for dependent-sized array types in C++?
1253 // Does it even make sense to build a CFG for an uninstantiated template?
1254 static const VariableArrayType *FindVA(const Type *t) {
1255  while (const ArrayType *vt = dyn_cast<ArrayType>(t)) {
1256  if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt))
1257  if (vat->getSizeExpr())
1258  return vat;
1259 
1260  t = vt->getElementType().getTypePtr();
1261  }
1262 
1263  return nullptr;
1264 }
1265 
1266 void CFGBuilder::consumeConstructionContext(
1267  const ConstructionContextLayer *Layer, Expr *E) {
1268  assert((isa<CXXConstructExpr>(E) || isa<CallExpr>(E) ||
1269  isa<ObjCMessageExpr>(E)) && "Expression cannot construct an object!");
1270  if (const ConstructionContextLayer *PreviouslyStoredLayer =
1271  ConstructionContextMap.lookup(E)) {
1272  (void)PreviouslyStoredLayer;
1273  // We might have visited this child when we were finding construction
1274  // contexts within its parents.
1275  assert(PreviouslyStoredLayer->isStrictlyMoreSpecificThan(Layer) &&
1276  "Already within a different construction context!");
1277  } else {
1278  ConstructionContextMap[E] = Layer;
1279  }
1280 }
1281 
1282 void CFGBuilder::findConstructionContexts(
1283  const ConstructionContextLayer *Layer, Stmt *Child) {
1284  if (!BuildOpts.AddRichCXXConstructors)
1285  return;
1286 
1287  if (!Child)
1288  return;
1289 
1290  auto withExtraLayer = [this, Layer](const ConstructionContextItem &Item) {
1291  return ConstructionContextLayer::create(cfg->getBumpVectorContext(), Item,
1292  Layer);
1293  };
1294 
1295  switch(Child->getStmtClass()) {
1296  case Stmt::CXXConstructExprClass:
1297  case Stmt::CXXTemporaryObjectExprClass: {
1298  // Support pre-C++17 copy elision AST.
1299  auto *CE = cast<CXXConstructExpr>(Child);
1300  if (BuildOpts.MarkElidedCXXConstructors && CE->isElidable()) {
1301  findConstructionContexts(withExtraLayer(CE), CE->getArg(0));
1302  }
1303 
1304  consumeConstructionContext(Layer, CE);
1305  break;
1306  }
1307  // FIXME: This, like the main visit, doesn't support CUDAKernelCallExpr.
1308  // FIXME: An isa<> would look much better but this whole switch is a
1309  // workaround for an internal compiler error in MSVC 2015 (see r326021).
1310  case Stmt::CallExprClass:
1311  case Stmt::CXXMemberCallExprClass:
1312  case Stmt::CXXOperatorCallExprClass:
1313  case Stmt::UserDefinedLiteralClass:
1314  case Stmt::ObjCMessageExprClass: {
1315  auto *E = cast<Expr>(Child);
1317  consumeConstructionContext(Layer, E);
1318  break;
1319  }
1320  case Stmt::ExprWithCleanupsClass: {
1321  auto *Cleanups = cast<ExprWithCleanups>(Child);
1322  findConstructionContexts(Layer, Cleanups->getSubExpr());
1323  break;
1324  }
1325  case Stmt::CXXFunctionalCastExprClass: {
1326  auto *Cast = cast<CXXFunctionalCastExpr>(Child);
1327  findConstructionContexts(Layer, Cast->getSubExpr());
1328  break;
1329  }
1330  case Stmt::ImplicitCastExprClass: {
1331  auto *Cast = cast<ImplicitCastExpr>(Child);
1332  // Should we support other implicit cast kinds?
1333  switch (Cast->getCastKind()) {
1334  case CK_NoOp:
1335  case CK_ConstructorConversion:
1336  findConstructionContexts(Layer, Cast->getSubExpr());
1337  default:
1338  break;
1339  }
1340  break;
1341  }
1342  case Stmt::CXXBindTemporaryExprClass: {
1343  auto *BTE = cast<CXXBindTemporaryExpr>(Child);
1344  findConstructionContexts(withExtraLayer(BTE), BTE->getSubExpr());
1345  break;
1346  }
1347  case Stmt::MaterializeTemporaryExprClass: {
1348  // Normally we don't want to search in MaterializeTemporaryExpr because
1349  // it indicates the beginning of a temporary object construction context,
1350  // so it shouldn't be found in the middle. However, if it is the beginning
1351  // of an elidable copy or move construction context, we need to include it.
1352  if (Layer->getItem().getKind() ==
1354  auto *MTE = cast<MaterializeTemporaryExpr>(Child);
1355  findConstructionContexts(withExtraLayer(MTE), MTE->GetTemporaryExpr());
1356  }
1357  break;
1358  }
1359  case Stmt::ConditionalOperatorClass: {
1360  auto *CO = cast<ConditionalOperator>(Child);
1361  if (Layer->getItem().getKind() !=
1363  // If the object returned by the conditional operator is not going to be a
1364  // temporary object that needs to be immediately materialized, then
1365  // it must be C++17 with its mandatory copy elision. Do not yet promise
1366  // to support this case.
1367  assert(!CO->getType()->getAsCXXRecordDecl() || CO->isGLValue() ||
1368  Context->getLangOpts().CPlusPlus17);
1369  break;
1370  }
1371  findConstructionContexts(Layer, CO->getLHS());
1372  findConstructionContexts(Layer, CO->getRHS());
1373  break;
1374  }
1375  default:
1376  break;
1377  }
1378 }
1379 
1380 void CFGBuilder::cleanupConstructionContext(Expr *E) {
1381  assert(BuildOpts.AddRichCXXConstructors &&
1382  "We should not be managing construction contexts!");
1383  assert(ConstructionContextMap.count(E) &&
1384  "Cannot exit construction context without the context!");
1385  ConstructionContextMap.erase(E);
1386 }
1387 
1388 
1389 /// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an
1390 /// arbitrary statement. Examples include a single expression or a function
1391 /// body (compound statement). The ownership of the returned CFG is
1392 /// transferred to the caller. If CFG construction fails, this method returns
1393 /// NULL.
1394 std::unique_ptr<CFG> CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) {
1395  assert(cfg.get());
1396  if (!Statement)
1397  return nullptr;
1398 
1399  // Create an empty block that will serve as the exit block for the CFG. Since
1400  // this is the first block added to the CFG, it will be implicitly registered
1401  // as the exit block.
1402  Succ = createBlock();
1403  assert(Succ == &cfg->getExit());
1404  Block = nullptr; // the EXIT block is empty. Create all other blocks lazily.
1405 
1406  assert(!(BuildOpts.AddImplicitDtors && BuildOpts.AddLifetime) &&
1407  "AddImplicitDtors and AddLifetime cannot be used at the same time");
1408 
1409  if (BuildOpts.AddImplicitDtors)
1410  if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D))
1411  addImplicitDtorsForDestructor(DD);
1412 
1413  // Visit the statements and create the CFG.
1414  CFGBlock *B = addStmt(Statement);
1415 
1416  if (badCFG)
1417  return nullptr;
1418 
1419  // For C++ constructor add initializers to CFG.
1420  if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) {
1421  for (auto *I : llvm::reverse(CD->inits())) {
1422  B = addInitializer(I);
1423  if (badCFG)
1424  return nullptr;
1425  }
1426  }
1427 
1428  if (B)
1429  Succ = B;
1430 
1431  // Backpatch the gotos whose label -> block mappings we didn't know when we
1432  // encountered them.
1433  for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(),
1434  E = BackpatchBlocks.end(); I != E; ++I ) {
1435 
1436  CFGBlock *B = I->block;
1437  const GotoStmt *G = cast<GotoStmt>(B->getTerminator());
1438  LabelMapTy::iterator LI = LabelMap.find(G->getLabel());
1439 
1440  // If there is no target for the goto, then we are looking at an
1441  // incomplete AST. Handle this by not registering a successor.
1442  if (LI == LabelMap.end()) continue;
1443 
1444  JumpTarget JT = LI->second;
1445  prependAutomaticObjLifetimeWithTerminator(B, I->scopePosition,
1446  JT.scopePosition);
1447  prependAutomaticObjDtorsWithTerminator(B, I->scopePosition,
1448  JT.scopePosition);
1449  const VarDecl *VD = prependAutomaticObjScopeEndWithTerminator(
1450  B, I->scopePosition, JT.scopePosition);
1451  appendScopeBegin(JT.block, VD, G);
1452  addSuccessor(B, JT.block);
1453  }
1454 
1455  // Add successors to the Indirect Goto Dispatch block (if we have one).
1456  if (CFGBlock *B = cfg->getIndirectGotoBlock())
1457  for (LabelSetTy::iterator I = AddressTakenLabels.begin(),
1458  E = AddressTakenLabels.end(); I != E; ++I ) {
1459  // Lookup the target block.
1460  LabelMapTy::iterator LI = LabelMap.find(*I);
1461 
1462  // If there is no target block that contains label, then we are looking
1463  // at an incomplete AST. Handle this by not registering a successor.
1464  if (LI == LabelMap.end()) continue;
1465 
1466  addSuccessor(B, LI->second.block);
1467  }
1468 
1469  // Create an empty entry block that has no predecessors.
1470  cfg->setEntry(createBlock());
1471 
1472  if (BuildOpts.AddRichCXXConstructors)
1473  assert(ConstructionContextMap.empty() &&
1474  "Not all construction contexts were cleaned up!");
1475 
1476  return std::move(cfg);
1477 }
1478 
1479 /// createBlock - Used to lazily create blocks that are connected
1480 /// to the current (global) succcessor.
1481 CFGBlock *CFGBuilder::createBlock(bool add_successor) {
1482  CFGBlock *B = cfg->createBlock();
1483  if (add_successor && Succ)
1484  addSuccessor(B, Succ);
1485  return B;
1486 }
1487 
1488 /// createNoReturnBlock - Used to create a block is a 'noreturn' point in the
1489 /// CFG. It is *not* connected to the current (global) successor, and instead
1490 /// directly tied to the exit block in order to be reachable.
1491 CFGBlock *CFGBuilder::createNoReturnBlock() {
1492  CFGBlock *B = createBlock(false);
1493  B->setHasNoReturnElement();
1494  addSuccessor(B, &cfg->getExit(), Succ);
1495  return B;
1496 }
1497 
1498 /// addInitializer - Add C++ base or member initializer element to CFG.
1499 CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) {
1500  if (!BuildOpts.AddInitializers)
1501  return Block;
1502 
1503  bool HasTemporaries = false;
1504 
1505  // Destructors of temporaries in initialization expression should be called
1506  // after initialization finishes.
1507  Expr *Init = I->getInit();
1508  if (Init) {
1509  HasTemporaries = isa<ExprWithCleanups>(Init);
1510 
1511  if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
1512  // Generate destructors for temporaries in initialization expression.
1513  TempDtorContext Context;
1514  VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
1515  /*BindToTemporary=*/false, Context);
1516  }
1517  }
1518 
1519  autoCreateBlock();
1520  appendInitializer(Block, I);
1521 
1522  if (Init) {
1523  findConstructionContexts(
1524  ConstructionContextLayer::create(cfg->getBumpVectorContext(), I),
1525  Init);
1526 
1527  if (HasTemporaries) {
1528  // For expression with temporaries go directly to subexpression to omit
1529  // generating destructors for the second time.
1530  return Visit(cast<ExprWithCleanups>(Init)->getSubExpr());
1531  }
1532  if (BuildOpts.AddCXXDefaultInitExprInCtors) {
1533  if (CXXDefaultInitExpr *Default = dyn_cast<CXXDefaultInitExpr>(Init)) {
1534  // In general, appending the expression wrapped by a CXXDefaultInitExpr
1535  // may cause the same Expr to appear more than once in the CFG. Doing it
1536  // here is safe because there's only one initializer per field.
1537  autoCreateBlock();
1538  appendStmt(Block, Default);
1539  if (Stmt *Child = Default->getExpr())
1540  if (CFGBlock *R = Visit(Child))
1541  Block = R;
1542  return Block;
1543  }
1544  }
1545  return Visit(Init);
1546  }
1547 
1548  return Block;
1549 }
1550 
1551 /// Retrieve the type of the temporary object whose lifetime was
1552 /// extended by a local reference with the given initializer.
1554  bool *FoundMTE = nullptr) {
1555  while (true) {
1556  // Skip parentheses.
1557  Init = Init->IgnoreParens();
1558 
1559  // Skip through cleanups.
1560  if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Init)) {
1561  Init = EWC->getSubExpr();
1562  continue;
1563  }
1564 
1565  // Skip through the temporary-materialization expression.
1566  if (const MaterializeTemporaryExpr *MTE
1567  = dyn_cast<MaterializeTemporaryExpr>(Init)) {
1568  Init = MTE->GetTemporaryExpr();
1569  if (FoundMTE)
1570  *FoundMTE = true;
1571  continue;
1572  }
1573 
1574  // Skip sub-object accesses into rvalues.
1575  SmallVector<const Expr *, 2> CommaLHSs;
1577  const Expr *SkippedInit =
1578  Init->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
1579  if (SkippedInit != Init) {
1580  Init = SkippedInit;
1581  continue;
1582  }
1583 
1584  break;
1585  }
1586 
1587  return Init->getType();
1588 }
1589 
1590 // TODO: Support adding LoopExit element to the CFG in case where the loop is
1591 // ended by ReturnStmt, GotoStmt or ThrowExpr.
1592 void CFGBuilder::addLoopExit(const Stmt *LoopStmt){
1593  if(!BuildOpts.AddLoopExit)
1594  return;
1595  autoCreateBlock();
1596  appendLoopExit(Block, LoopStmt);
1597 }
1598 
1599 void CFGBuilder::getDeclsWithEndedScope(LocalScope::const_iterator B,
1600  LocalScope::const_iterator E, Stmt *S) {
1601  if (!BuildOpts.AddScopes)
1602  return;
1603 
1604  if (B == E)
1605  return;
1606 
1607  // To go from B to E, one first goes up the scopes from B to P
1608  // then sideways in one scope from P to P' and then down
1609  // the scopes from P' to E.
1610  // The lifetime of all objects between B and P end.
1611  LocalScope::const_iterator P = B.shared_parent(E);
1612  int Dist = B.distance(P);
1613  if (Dist <= 0)
1614  return;
1615 
1616  for (LocalScope::const_iterator I = B; I != P; ++I)
1617  if (I.pointsToFirstDeclaredVar())
1618  DeclsWithEndedScope.insert(*I);
1619 }
1620 
1621 void CFGBuilder::addAutomaticObjHandling(LocalScope::const_iterator B,
1622  LocalScope::const_iterator E,
1623  Stmt *S) {
1624  getDeclsWithEndedScope(B, E, S);
1625  if (BuildOpts.AddScopes)
1626  addScopesEnd(B, E, S);
1627  if (BuildOpts.AddImplicitDtors)
1628  addAutomaticObjDtors(B, E, S);
1629  if (BuildOpts.AddLifetime)
1630  addLifetimeEnds(B, E, S);
1631 }
1632 
1633 /// Add to current block automatic objects that leave the scope.
1634 void CFGBuilder::addLifetimeEnds(LocalScope::const_iterator B,
1635  LocalScope::const_iterator E, Stmt *S) {
1636  if (!BuildOpts.AddLifetime)
1637  return;
1638 
1639  if (B == E)
1640  return;
1641 
1642  // To go from B to E, one first goes up the scopes from B to P
1643  // then sideways in one scope from P to P' and then down
1644  // the scopes from P' to E.
1645  // The lifetime of all objects between B and P end.
1646  LocalScope::const_iterator P = B.shared_parent(E);
1647  int dist = B.distance(P);
1648  if (dist <= 0)
1649  return;
1650 
1651  // We need to perform the scope leaving in reverse order
1652  SmallVector<VarDecl *, 10> DeclsTrivial;
1653  SmallVector<VarDecl *, 10> DeclsNonTrivial;
1654  DeclsTrivial.reserve(dist);
1655  DeclsNonTrivial.reserve(dist);
1656 
1657  for (LocalScope::const_iterator I = B; I != P; ++I)
1658  if (hasTrivialDestructor(*I))
1659  DeclsTrivial.push_back(*I);
1660  else
1661  DeclsNonTrivial.push_back(*I);
1662 
1663  autoCreateBlock();
1664  // object with trivial destructor end their lifetime last (when storage
1665  // duration ends)
1666  for (SmallVectorImpl<VarDecl *>::reverse_iterator I = DeclsTrivial.rbegin(),
1667  E = DeclsTrivial.rend();
1668  I != E; ++I)
1669  appendLifetimeEnds(Block, *I, S);
1670 
1672  I = DeclsNonTrivial.rbegin(),
1673  E = DeclsNonTrivial.rend();
1674  I != E; ++I)
1675  appendLifetimeEnds(Block, *I, S);
1676 }
1677 
1678 /// Add to current block markers for ending scopes.
1679 void CFGBuilder::addScopesEnd(LocalScope::const_iterator B,
1680  LocalScope::const_iterator E, Stmt *S) {
1681  // If implicit destructors are enabled, we'll add scope ends in
1682  // addAutomaticObjDtors.
1683  if (BuildOpts.AddImplicitDtors)
1684  return;
1685 
1686  autoCreateBlock();
1687 
1688  for (auto I = DeclsWithEndedScope.rbegin(), E = DeclsWithEndedScope.rend();
1689  I != E; ++I)
1690  appendScopeEnd(Block, *I, S);
1691 
1692  return;
1693 }
1694 
1695 /// addAutomaticObjDtors - Add to current block automatic objects destructors
1696 /// for objects in range of local scope positions. Use S as trigger statement
1697 /// for destructors.
1698 void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B,
1699  LocalScope::const_iterator E, Stmt *S) {
1700  if (!BuildOpts.AddImplicitDtors)
1701  return;
1702 
1703  if (B == E)
1704  return;
1705 
1706  // We need to append the destructors in reverse order, but any one of them
1707  // may be a no-return destructor which changes the CFG. As a result, buffer
1708  // this sequence up and replay them in reverse order when appending onto the
1709  // CFGBlock(s).
1711  Decls.reserve(B.distance(E));
1712  for (LocalScope::const_iterator I = B; I != E; ++I)
1713  Decls.push_back(*I);
1714 
1715  for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(),
1716  E = Decls.rend();
1717  I != E; ++I) {
1718  if (hasTrivialDestructor(*I)) {
1719  // If AddScopes is enabled and *I is a first variable in a scope, add a
1720  // ScopeEnd marker in a Block.
1721  if (BuildOpts.AddScopes && DeclsWithEndedScope.count(*I)) {
1722  autoCreateBlock();
1723  appendScopeEnd(Block, *I, S);
1724  }
1725  continue;
1726  }
1727  // If this destructor is marked as a no-return destructor, we need to
1728  // create a new block for the destructor which does not have as a successor
1729  // anything built thus far: control won't flow out of this block.
1730  QualType Ty = (*I)->getType();
1731  if (Ty->isReferenceType()) {
1732  Ty = getReferenceInitTemporaryType((*I)->getInit());
1733  }
1734  Ty = Context->getBaseElementType(Ty);
1735 
1736  if (Ty->getAsCXXRecordDecl()->isAnyDestructorNoReturn())
1737  Block = createNoReturnBlock();
1738  else
1739  autoCreateBlock();
1740 
1741  // Add ScopeEnd just after automatic obj destructor.
1742  if (BuildOpts.AddScopes && DeclsWithEndedScope.count(*I))
1743  appendScopeEnd(Block, *I, S);
1744  appendAutomaticObjDtor(Block, *I, S);
1745  }
1746 }
1747 
1748 /// addImplicitDtorsForDestructor - Add implicit destructors generated for
1749 /// base and member objects in destructor.
1750 void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) {
1751  assert(BuildOpts.AddImplicitDtors &&
1752  "Can be called only when dtors should be added");
1753  const CXXRecordDecl *RD = DD->getParent();
1754 
1755  // At the end destroy virtual base objects.
1756  for (const auto &VI : RD->vbases()) {
1757  const CXXRecordDecl *CD = VI.getType()->getAsCXXRecordDecl();
1758  if (!CD->hasTrivialDestructor()) {
1759  autoCreateBlock();
1760  appendBaseDtor(Block, &VI);
1761  }
1762  }
1763 
1764  // Before virtual bases destroy direct base objects.
1765  for (const auto &BI : RD->bases()) {
1766  if (!BI.isVirtual()) {
1767  const CXXRecordDecl *CD = BI.getType()->getAsCXXRecordDecl();
1768  if (!CD->hasTrivialDestructor()) {
1769  autoCreateBlock();
1770  appendBaseDtor(Block, &BI);
1771  }
1772  }
1773  }
1774 
1775  // First destroy member objects.
1776  for (auto *FI : RD->fields()) {
1777  // Check for constant size array. Set type to array element type.
1778  QualType QT = FI->getType();
1779  if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
1780  if (AT->getSize() == 0)
1781  continue;
1782  QT = AT->getElementType();
1783  }
1784 
1785  if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
1786  if (!CD->hasTrivialDestructor()) {
1787  autoCreateBlock();
1788  appendMemberDtor(Block, FI);
1789  }
1790  }
1791 }
1792 
1793 /// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either
1794 /// way return valid LocalScope object.
1795 LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) {
1796  if (Scope)
1797  return Scope;
1798  llvm::BumpPtrAllocator &alloc = cfg->getAllocator();
1799  return new (alloc.Allocate<LocalScope>())
1800  LocalScope(BumpVectorContext(alloc), ScopePos);
1801 }
1802 
1803 /// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement
1804 /// that should create implicit scope (e.g. if/else substatements).
1805 void CFGBuilder::addLocalScopeForStmt(Stmt *S) {
1806  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1807  !BuildOpts.AddScopes)
1808  return;
1809 
1810  LocalScope *Scope = nullptr;
1811 
1812  // For compound statement we will be creating explicit scope.
1813  if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
1814  for (auto *BI : CS->body()) {
1815  Stmt *SI = BI->stripLabelLikeStatements();
1816  if (DeclStmt *DS = dyn_cast<DeclStmt>(SI))
1817  Scope = addLocalScopeForDeclStmt(DS, Scope);
1818  }
1819  return;
1820  }
1821 
1822  // For any other statement scope will be implicit and as such will be
1823  // interesting only for DeclStmt.
1824  if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements()))
1825  addLocalScopeForDeclStmt(DS);
1826 }
1827 
1828 /// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will
1829 /// reuse Scope if not NULL.
1830 LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS,
1831  LocalScope* Scope) {
1832  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1833  !BuildOpts.AddScopes)
1834  return Scope;
1835 
1836  for (auto *DI : DS->decls())
1837  if (VarDecl *VD = dyn_cast<VarDecl>(DI))
1838  Scope = addLocalScopeForVarDecl(VD, Scope);
1839  return Scope;
1840 }
1841 
1842 bool CFGBuilder::hasTrivialDestructor(VarDecl *VD) {
1843  // Check for const references bound to temporary. Set type to pointee.
1844  QualType QT = VD->getType();
1845  if (QT->isReferenceType()) {
1846  // Attempt to determine whether this declaration lifetime-extends a
1847  // temporary.
1848  //
1849  // FIXME: This is incorrect. Non-reference declarations can lifetime-extend
1850  // temporaries, and a single declaration can extend multiple temporaries.
1851  // We should look at the storage duration on each nested
1852  // MaterializeTemporaryExpr instead.
1853 
1854  const Expr *Init = VD->getInit();
1855  if (!Init) {
1856  // Probably an exception catch-by-reference variable.
1857  // FIXME: It doesn't really mean that the object has a trivial destructor.
1858  // Also are there other cases?
1859  return true;
1860  }
1861 
1862  // Lifetime-extending a temporary?
1863  bool FoundMTE = false;
1864  QT = getReferenceInitTemporaryType(Init, &FoundMTE);
1865  if (!FoundMTE)
1866  return true;
1867  }
1868 
1869  // Check for constant size array. Set type to array element type.
1870  while (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
1871  if (AT->getSize() == 0)
1872  return true;
1873  QT = AT->getElementType();
1874  }
1875 
1876  // Check if type is a C++ class with non-trivial destructor.
1877  if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
1878  return !CD->hasDefinition() || CD->hasTrivialDestructor();
1879  return true;
1880 }
1881 
1882 /// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will
1883 /// create add scope for automatic objects and temporary objects bound to
1884 /// const reference. Will reuse Scope if not NULL.
1885 LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD,
1886  LocalScope* Scope) {
1887  assert(!(BuildOpts.AddImplicitDtors && BuildOpts.AddLifetime) &&
1888  "AddImplicitDtors and AddLifetime cannot be used at the same time");
1889  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1890  !BuildOpts.AddScopes)
1891  return Scope;
1892 
1893  // Check if variable is local.
1894  switch (VD->getStorageClass()) {
1895  case SC_None:
1896  case SC_Auto:
1897  case SC_Register:
1898  break;
1899  default: return Scope;
1900  }
1901 
1902  if (BuildOpts.AddImplicitDtors) {
1903  if (!hasTrivialDestructor(VD) || BuildOpts.AddScopes) {
1904  // Add the variable to scope
1905  Scope = createOrReuseLocalScope(Scope);
1906  Scope->addVar(VD);
1907  ScopePos = Scope->begin();
1908  }
1909  return Scope;
1910  }
1911 
1912  assert(BuildOpts.AddLifetime);
1913  // Add the variable to scope
1914  Scope = createOrReuseLocalScope(Scope);
1915  Scope->addVar(VD);
1916  ScopePos = Scope->begin();
1917  return Scope;
1918 }
1919 
1920 /// addLocalScopeAndDtors - For given statement add local scope for it and
1921 /// add destructors that will cleanup the scope. Will reuse Scope if not NULL.
1922 void CFGBuilder::addLocalScopeAndDtors(Stmt *S) {
1923  LocalScope::const_iterator scopeBeginPos = ScopePos;
1924  addLocalScopeForStmt(S);
1925  addAutomaticObjHandling(ScopePos, scopeBeginPos, S);
1926 }
1927 
1928 /// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for
1929 /// variables with automatic storage duration to CFGBlock's elements vector.
1930 /// Elements will be prepended to physical beginning of the vector which
1931 /// happens to be logical end. Use blocks terminator as statement that specifies
1932 /// destructors call site.
1933 /// FIXME: This mechanism for adding automatic destructors doesn't handle
1934 /// no-return destructors properly.
1935 void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
1936  LocalScope::const_iterator B, LocalScope::const_iterator E) {
1937  if (!BuildOpts.AddImplicitDtors)
1938  return;
1939  BumpVectorContext &C = cfg->getBumpVectorContext();
1940  CFGBlock::iterator InsertPos
1941  = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C);
1942  for (LocalScope::const_iterator I = B; I != E; ++I)
1943  InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I,
1944  Blk->getTerminator());
1945 }
1946 
1947 /// prependAutomaticObjLifetimeWithTerminator - Prepend lifetime CFGElements for
1948 /// variables with automatic storage duration to CFGBlock's elements vector.
1949 /// Elements will be prepended to physical beginning of the vector which
1950 /// happens to be logical end. Use blocks terminator as statement that specifies
1951 /// where lifetime ends.
1952 void CFGBuilder::prependAutomaticObjLifetimeWithTerminator(
1953  CFGBlock *Blk, LocalScope::const_iterator B, LocalScope::const_iterator E) {
1954  if (!BuildOpts.AddLifetime)
1955  return;
1956  BumpVectorContext &C = cfg->getBumpVectorContext();
1957  CFGBlock::iterator InsertPos =
1958  Blk->beginLifetimeEndsInsert(Blk->end(), B.distance(E), C);
1959  for (LocalScope::const_iterator I = B; I != E; ++I)
1960  InsertPos = Blk->insertLifetimeEnds(InsertPos, *I, Blk->getTerminator());
1961 }
1962 
1963 /// prependAutomaticObjScopeEndWithTerminator - Prepend scope end CFGElements for
1964 /// variables with automatic storage duration to CFGBlock's elements vector.
1965 /// Elements will be prepended to physical beginning of the vector which
1966 /// happens to be logical end. Use blocks terminator as statement that specifies
1967 /// where scope ends.
1968 const VarDecl *
1969 CFGBuilder::prependAutomaticObjScopeEndWithTerminator(
1970  CFGBlock *Blk, LocalScope::const_iterator B, LocalScope::const_iterator E) {
1971  if (!BuildOpts.AddScopes)
1972  return nullptr;
1973  BumpVectorContext &C = cfg->getBumpVectorContext();
1974  CFGBlock::iterator InsertPos =
1975  Blk->beginScopeEndInsert(Blk->end(), 1, C);
1976  LocalScope::const_iterator PlaceToInsert = B;
1977  for (LocalScope::const_iterator I = B; I != E; ++I)
1978  PlaceToInsert = I;
1979  Blk->insertScopeEnd(InsertPos, *PlaceToInsert, Blk->getTerminator());
1980  return *PlaceToInsert;
1981 }
1982 
1983 /// Visit - Walk the subtree of a statement and add extra
1984 /// blocks for ternary operators, &&, and ||. We also process "," and
1985 /// DeclStmts (which may contain nested control-flow).
1986 CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) {
1987  if (!S) {
1988  badCFG = true;
1989  return nullptr;
1990  }
1991 
1992  if (Expr *E = dyn_cast<Expr>(S))
1993  S = E->IgnoreParens();
1994 
1995  switch (S->getStmtClass()) {
1996  default:
1997  return VisitStmt(S, asc);
1998 
1999  case Stmt::AddrLabelExprClass:
2000  return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc);
2001 
2002  case Stmt::BinaryConditionalOperatorClass:
2003  return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc);
2004 
2005  case Stmt::BinaryOperatorClass:
2006  return VisitBinaryOperator(cast<BinaryOperator>(S), asc);
2007 
2008  case Stmt::BlockExprClass:
2009  return VisitBlockExpr(cast<BlockExpr>(S), asc);
2010 
2011  case Stmt::BreakStmtClass:
2012  return VisitBreakStmt(cast<BreakStmt>(S));
2013 
2014  case Stmt::CallExprClass:
2015  case Stmt::CXXOperatorCallExprClass:
2016  case Stmt::CXXMemberCallExprClass:
2017  case Stmt::UserDefinedLiteralClass:
2018  return VisitCallExpr(cast<CallExpr>(S), asc);
2019 
2020  case Stmt::CaseStmtClass:
2021  return VisitCaseStmt(cast<CaseStmt>(S));
2022 
2023  case Stmt::ChooseExprClass:
2024  return VisitChooseExpr(cast<ChooseExpr>(S), asc);
2025 
2026  case Stmt::CompoundStmtClass:
2027  return VisitCompoundStmt(cast<CompoundStmt>(S));
2028 
2029  case Stmt::ConditionalOperatorClass:
2030  return VisitConditionalOperator(cast<ConditionalOperator>(S), asc);
2031 
2032  case Stmt::ContinueStmtClass:
2033  return VisitContinueStmt(cast<ContinueStmt>(S));
2034 
2035  case Stmt::CXXCatchStmtClass:
2036  return VisitCXXCatchStmt(cast<CXXCatchStmt>(S));
2037 
2038  case Stmt::ExprWithCleanupsClass:
2039  return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc);
2040 
2041  case Stmt::CXXDefaultArgExprClass:
2042  case Stmt::CXXDefaultInitExprClass:
2043  // FIXME: The expression inside a CXXDefaultArgExpr is owned by the
2044  // called function's declaration, not by the caller. If we simply add
2045  // this expression to the CFG, we could end up with the same Expr
2046  // appearing multiple times.
2047  // PR13385 / <rdar://problem/12156507>
2048  //
2049  // It's likewise possible for multiple CXXDefaultInitExprs for the same
2050  // expression to be used in the same function (through aggregate
2051  // initialization).
2052  return VisitStmt(S, asc);
2053 
2054  case Stmt::CXXBindTemporaryExprClass:
2055  return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc);
2056 
2057  case Stmt::CXXConstructExprClass:
2058  return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc);
2059 
2060  case Stmt::CXXNewExprClass:
2061  return VisitCXXNewExpr(cast<CXXNewExpr>(S), asc);
2062 
2063  case Stmt::CXXDeleteExprClass:
2064  return VisitCXXDeleteExpr(cast<CXXDeleteExpr>(S), asc);
2065 
2066  case Stmt::CXXFunctionalCastExprClass:
2067  return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc);
2068 
2069  case Stmt::CXXTemporaryObjectExprClass:
2070  return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc);
2071 
2072  case Stmt::CXXThrowExprClass:
2073  return VisitCXXThrowExpr(cast<CXXThrowExpr>(S));
2074 
2075  case Stmt::CXXTryStmtClass:
2076  return VisitCXXTryStmt(cast<CXXTryStmt>(S));
2077 
2078  case Stmt::CXXForRangeStmtClass:
2079  return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S));
2080 
2081  case Stmt::DeclStmtClass:
2082  return VisitDeclStmt(cast<DeclStmt>(S));
2083 
2084  case Stmt::DefaultStmtClass:
2085  return VisitDefaultStmt(cast<DefaultStmt>(S));
2086 
2087  case Stmt::DoStmtClass:
2088  return VisitDoStmt(cast<DoStmt>(S));
2089 
2090  case Stmt::ForStmtClass:
2091  return VisitForStmt(cast<ForStmt>(S));
2092 
2093  case Stmt::GotoStmtClass:
2094  return VisitGotoStmt(cast<GotoStmt>(S));
2095 
2096  case Stmt::IfStmtClass:
2097  return VisitIfStmt(cast<IfStmt>(S));
2098 
2099  case Stmt::ImplicitCastExprClass:
2100  return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc);
2101 
2102  case Stmt::IndirectGotoStmtClass:
2103  return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S));
2104 
2105  case Stmt::LabelStmtClass:
2106  return VisitLabelStmt(cast<LabelStmt>(S));
2107 
2108  case Stmt::LambdaExprClass:
2109  return VisitLambdaExpr(cast<LambdaExpr>(S), asc);
2110 
2111  case Stmt::MaterializeTemporaryExprClass:
2112  return VisitMaterializeTemporaryExpr(cast<MaterializeTemporaryExpr>(S),
2113  asc);
2114 
2115  case Stmt::MemberExprClass:
2116  return VisitMemberExpr(cast<MemberExpr>(S), asc);
2117 
2118  case Stmt::NullStmtClass:
2119  return Block;
2120 
2121  case Stmt::ObjCAtCatchStmtClass:
2122  return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S));
2123 
2124  case Stmt::ObjCAutoreleasePoolStmtClass:
2125  return VisitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(S));
2126 
2127  case Stmt::ObjCAtSynchronizedStmtClass:
2128  return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S));
2129 
2130  case Stmt::ObjCAtThrowStmtClass:
2131  return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S));
2132 
2133  case Stmt::ObjCAtTryStmtClass:
2134  return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S));
2135 
2136  case Stmt::ObjCForCollectionStmtClass:
2137  return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S));
2138 
2139  case Stmt::ObjCMessageExprClass:
2140  return VisitObjCMessageExpr(cast<ObjCMessageExpr>(S), asc);
2141 
2142  case Stmt::OpaqueValueExprClass:
2143  return Block;
2144 
2145  case Stmt::PseudoObjectExprClass:
2146  return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S));
2147 
2148  case Stmt::ReturnStmtClass:
2149  return VisitReturnStmt(cast<ReturnStmt>(S));
2150 
2151  case Stmt::SEHExceptStmtClass:
2152  return VisitSEHExceptStmt(cast<SEHExceptStmt>(S));
2153 
2154  case Stmt::SEHFinallyStmtClass:
2155  return VisitSEHFinallyStmt(cast<SEHFinallyStmt>(S));
2156 
2157  case Stmt::SEHLeaveStmtClass:
2158  return VisitSEHLeaveStmt(cast<SEHLeaveStmt>(S));
2159 
2160  case Stmt::SEHTryStmtClass:
2161  return VisitSEHTryStmt(cast<SEHTryStmt>(S));
2162 
2163  case Stmt::UnaryExprOrTypeTraitExprClass:
2164  return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S),
2165  asc);
2166 
2167  case Stmt::StmtExprClass:
2168  return VisitStmtExpr(cast<StmtExpr>(S), asc);
2169 
2170  case Stmt::SwitchStmtClass:
2171  return VisitSwitchStmt(cast<SwitchStmt>(S));
2172 
2173  case Stmt::UnaryOperatorClass:
2174  return VisitUnaryOperator(cast<UnaryOperator>(S), asc);
2175 
2176  case Stmt::WhileStmtClass:
2177  return VisitWhileStmt(cast<WhileStmt>(S));
2178  }
2179 }
2180 
2181 CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) {
2182  if (asc.alwaysAdd(*this, S)) {
2183  autoCreateBlock();
2184  appendStmt(Block, S);
2185  }
2186 
2187  return VisitChildren(S);
2188 }
2189 
2190 /// VisitChildren - Visit the children of a Stmt.
2191 CFGBlock *CFGBuilder::VisitChildren(Stmt *S) {
2192  CFGBlock *B = Block;
2193 
2194  // Visit the children in their reverse order so that they appear in
2195  // left-to-right (natural) order in the CFG.
2196  reverse_children RChildren(S);
2197  for (reverse_children::iterator I = RChildren.begin(), E = RChildren.end();
2198  I != E; ++I) {
2199  if (Stmt *Child = *I)
2200  if (CFGBlock *R = Visit(Child))
2201  B = R;
2202  }
2203  return B;
2204 }
2205 
2206 CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A,
2207  AddStmtChoice asc) {
2208  AddressTakenLabels.insert(A->getLabel());
2209 
2210  if (asc.alwaysAdd(*this, A)) {
2211  autoCreateBlock();
2212  appendStmt(Block, A);
2213  }
2214 
2215  return Block;
2216 }
2217 
2218 CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U,
2219  AddStmtChoice asc) {
2220  if (asc.alwaysAdd(*this, U)) {
2221  autoCreateBlock();
2222  appendStmt(Block, U);
2223  }
2224 
2225  return Visit(U->getSubExpr(), AddStmtChoice());
2226 }
2227 
2228 CFGBlock *CFGBuilder::VisitLogicalOperator(BinaryOperator *B) {
2229  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2230  appendStmt(ConfluenceBlock, B);
2231 
2232  if (badCFG)
2233  return nullptr;
2234 
2235  return VisitLogicalOperator(B, nullptr, ConfluenceBlock,
2236  ConfluenceBlock).first;
2237 }
2238 
2239 std::pair<CFGBlock*, CFGBlock*>
2240 CFGBuilder::VisitLogicalOperator(BinaryOperator *B,
2241  Stmt *Term,
2242  CFGBlock *TrueBlock,
2243  CFGBlock *FalseBlock) {
2244  // Introspect the RHS. If it is a nested logical operation, we recursively
2245  // build the CFG using this function. Otherwise, resort to default
2246  // CFG construction behavior.
2247  Expr *RHS = B->getRHS()->IgnoreParens();
2248  CFGBlock *RHSBlock, *ExitBlock;
2249 
2250  do {
2251  if (BinaryOperator *B_RHS = dyn_cast<BinaryOperator>(RHS))
2252  if (B_RHS->isLogicalOp()) {
2253  std::tie(RHSBlock, ExitBlock) =
2254  VisitLogicalOperator(B_RHS, Term, TrueBlock, FalseBlock);
2255  break;
2256  }
2257 
2258  // The RHS is not a nested logical operation. Don't push the terminator
2259  // down further, but instead visit RHS and construct the respective
2260  // pieces of the CFG, and link up the RHSBlock with the terminator
2261  // we have been provided.
2262  ExitBlock = RHSBlock = createBlock(false);
2263 
2264  // Even though KnownVal is only used in the else branch of the next
2265  // conditional, tryEvaluateBool performs additional checking on the
2266  // Expr, so it should be called unconditionally.
2267  TryResult KnownVal = tryEvaluateBool(RHS);
2268  if (!KnownVal.isKnown())
2269  KnownVal = tryEvaluateBool(B);
2270 
2271  if (!Term) {
2272  assert(TrueBlock == FalseBlock);
2273  addSuccessor(RHSBlock, TrueBlock);
2274  }
2275  else {
2276  RHSBlock->setTerminator(Term);
2277  addSuccessor(RHSBlock, TrueBlock, !KnownVal.isFalse());
2278  addSuccessor(RHSBlock, FalseBlock, !KnownVal.isTrue());
2279  }
2280 
2281  Block = RHSBlock;
2282  RHSBlock = addStmt(RHS);
2283  }
2284  while (false);
2285 
2286  if (badCFG)
2287  return std::make_pair(nullptr, nullptr);
2288 
2289  // Generate the blocks for evaluating the LHS.
2290  Expr *LHS = B->getLHS()->IgnoreParens();
2291 
2292  if (BinaryOperator *B_LHS = dyn_cast<BinaryOperator>(LHS))
2293  if (B_LHS->isLogicalOp()) {
2294  if (B->getOpcode() == BO_LOr)
2295  FalseBlock = RHSBlock;
2296  else
2297  TrueBlock = RHSBlock;
2298 
2299  // For the LHS, treat 'B' as the terminator that we want to sink
2300  // into the nested branch. The RHS always gets the top-most
2301  // terminator.
2302  return VisitLogicalOperator(B_LHS, B, TrueBlock, FalseBlock);
2303  }
2304 
2305  // Create the block evaluating the LHS.
2306  // This contains the '&&' or '||' as the terminator.
2307  CFGBlock *LHSBlock = createBlock(false);
2308  LHSBlock->setTerminator(B);
2309 
2310  Block = LHSBlock;
2311  CFGBlock *EntryLHSBlock = addStmt(LHS);
2312 
2313  if (badCFG)
2314  return std::make_pair(nullptr, nullptr);
2315 
2316  // See if this is a known constant.
2317  TryResult KnownVal = tryEvaluateBool(LHS);
2318 
2319  // Now link the LHSBlock with RHSBlock.
2320  if (B->getOpcode() == BO_LOr) {
2321  addSuccessor(LHSBlock, TrueBlock, !KnownVal.isFalse());
2322  addSuccessor(LHSBlock, RHSBlock, !KnownVal.isTrue());
2323  } else {
2324  assert(B->getOpcode() == BO_LAnd);
2325  addSuccessor(LHSBlock, RHSBlock, !KnownVal.isFalse());
2326  addSuccessor(LHSBlock, FalseBlock, !KnownVal.isTrue());
2327  }
2328 
2329  return std::make_pair(EntryLHSBlock, ExitBlock);
2330 }
2331 
2332 CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B,
2333  AddStmtChoice asc) {
2334  // && or ||
2335  if (B->isLogicalOp())
2336  return VisitLogicalOperator(B);
2337 
2338  if (B->getOpcode() == BO_Comma) { // ,
2339  autoCreateBlock();
2340  appendStmt(Block, B);
2341  addStmt(B->getRHS());
2342  return addStmt(B->getLHS());
2343  }
2344 
2345  if (B->isAssignmentOp()) {
2346  if (asc.alwaysAdd(*this, B)) {
2347  autoCreateBlock();
2348  appendStmt(Block, B);
2349  }
2350  Visit(B->getLHS());
2351  return Visit(B->getRHS());
2352  }
2353 
2354  if (asc.alwaysAdd(*this, B)) {
2355  autoCreateBlock();
2356  appendStmt(Block, B);
2357  }
2358 
2359  CFGBlock *RBlock = Visit(B->getRHS());
2360  CFGBlock *LBlock = Visit(B->getLHS());
2361  // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr
2362  // containing a DoStmt, and the LHS doesn't create a new block, then we should
2363  // return RBlock. Otherwise we'll incorrectly return NULL.
2364  return (LBlock ? LBlock : RBlock);
2365 }
2366 
2367 CFGBlock *CFGBuilder::VisitNoRecurse(Expr *E, AddStmtChoice asc) {
2368  if (asc.alwaysAdd(*this, E)) {
2369  autoCreateBlock();
2370  appendStmt(Block, E);
2371  }
2372  return Block;
2373 }
2374 
2375 CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) {
2376  // "break" is a control-flow statement. Thus we stop processing the current
2377  // block.
2378  if (badCFG)
2379  return nullptr;
2380 
2381  // Now create a new block that ends with the break statement.
2382  Block = createBlock(false);
2383  Block->setTerminator(B);
2384 
2385  // If there is no target for the break, then we are looking at an incomplete
2386  // AST. This means that the CFG cannot be constructed.
2387  if (BreakJumpTarget.block) {
2388  addAutomaticObjHandling(ScopePos, BreakJumpTarget.scopePosition, B);
2389  addSuccessor(Block, BreakJumpTarget.block);
2390  } else
2391  badCFG = true;
2392 
2393  return Block;
2394 }
2395 
2396 static bool CanThrow(Expr *E, ASTContext &Ctx) {
2397  QualType Ty = E->getType();
2398  if (Ty->isFunctionPointerType())
2399  Ty = Ty->getAs<PointerType>()->getPointeeType();
2400  else if (Ty->isBlockPointerType())
2401  Ty = Ty->getAs<BlockPointerType>()->getPointeeType();
2402 
2403  const FunctionType *FT = Ty->getAs<FunctionType>();
2404  if (FT) {
2405  if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT))
2406  if (!isUnresolvedExceptionSpec(Proto->getExceptionSpecType()) &&
2407  Proto->isNothrow())
2408  return false;
2409  }
2410  return true;
2411 }
2412 
2413 CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) {
2414  // Compute the callee type.
2415  QualType calleeType = C->getCallee()->getType();
2416  if (calleeType == Context->BoundMemberTy) {
2417  QualType boundType = Expr::findBoundMemberType(C->getCallee());
2418 
2419  // We should only get a null bound type if processing a dependent
2420  // CFG. Recover by assuming nothing.
2421  if (!boundType.isNull()) calleeType = boundType;
2422  }
2423 
2424  findConstructionContextsForArguments(C);
2425 
2426  // If this is a call to a no-return function, this stops the block here.
2427  bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn();
2428 
2429  bool AddEHEdge = false;
2430 
2431  // Languages without exceptions are assumed to not throw.
2432  if (Context->getLangOpts().Exceptions) {
2433  if (BuildOpts.AddEHEdges)
2434  AddEHEdge = true;
2435  }
2436 
2437  // If this is a call to a builtin function, it might not actually evaluate
2438  // its arguments. Don't add them to the CFG if this is the case.
2439  bool OmitArguments = false;
2440 
2441  if (FunctionDecl *FD = C->getDirectCallee()) {
2442  if (FD->isNoReturn() || C->isBuiltinAssumeFalse(*Context))
2443  NoReturn = true;
2444  if (FD->hasAttr<NoThrowAttr>())
2445  AddEHEdge = false;
2446  if (FD->getBuiltinID() == Builtin::BI__builtin_object_size)
2447  OmitArguments = true;
2448  }
2449 
2450  if (!CanThrow(C->getCallee(), *Context))
2451  AddEHEdge = false;
2452 
2453  if (OmitArguments) {
2454  assert(!NoReturn && "noreturn calls with unevaluated args not implemented");
2455  assert(!AddEHEdge && "EH calls with unevaluated args not implemented");
2456  autoCreateBlock();
2457  appendStmt(Block, C);
2458  return Visit(C->getCallee());
2459  }
2460 
2461  if (!NoReturn && !AddEHEdge) {
2462  autoCreateBlock();
2463  appendCall(Block, C);
2464 
2465  return VisitChildren(C);
2466  }
2467 
2468  if (Block) {
2469  Succ = Block;
2470  if (badCFG)
2471  return nullptr;
2472  }
2473 
2474  if (NoReturn)
2475  Block = createNoReturnBlock();
2476  else
2477  Block = createBlock();
2478 
2479  appendCall(Block, C);
2480 
2481  if (AddEHEdge) {
2482  // Add exceptional edges.
2483  if (TryTerminatedBlock)
2484  addSuccessor(Block, TryTerminatedBlock);
2485  else
2486  addSuccessor(Block, &cfg->getExit());
2487  }
2488 
2489  return VisitChildren(C);
2490 }
2491 
2492 CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C,
2493  AddStmtChoice asc) {
2494  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2495  appendStmt(ConfluenceBlock, C);
2496  if (badCFG)
2497  return nullptr;
2498 
2499  AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2500  Succ = ConfluenceBlock;
2501  Block = nullptr;
2502  CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd);
2503  if (badCFG)
2504  return nullptr;
2505 
2506  Succ = ConfluenceBlock;
2507  Block = nullptr;
2508  CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd);
2509  if (badCFG)
2510  return nullptr;
2511 
2512  Block = createBlock(false);
2513  // See if this is a known constant.
2514  const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2515  addSuccessor(Block, KnownVal.isFalse() ? nullptr : LHSBlock);
2516  addSuccessor(Block, KnownVal.isTrue() ? nullptr : RHSBlock);
2517  Block->setTerminator(C);
2518  return addStmt(C->getCond());
2519 }
2520 
2521 CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) {
2522  LocalScope::const_iterator scopeBeginPos = ScopePos;
2523  addLocalScopeForStmt(C);
2524 
2525  if (!C->body_empty() && !isa<ReturnStmt>(*C->body_rbegin())) {
2526  // If the body ends with a ReturnStmt, the dtors will be added in
2527  // VisitReturnStmt.
2528  addAutomaticObjHandling(ScopePos, scopeBeginPos, C);
2529  }
2530 
2531  CFGBlock *LastBlock = Block;
2532 
2534  I != E; ++I ) {
2535  // If we hit a segment of code just containing ';' (NullStmts), we can
2536  // get a null block back. In such cases, just use the LastBlock
2537  if (CFGBlock *newBlock = addStmt(*I))
2538  LastBlock = newBlock;
2539 
2540  if (badCFG)
2541  return nullptr;
2542  }
2543 
2544  return LastBlock;
2545 }
2546 
2547 CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C,
2548  AddStmtChoice asc) {
2549  const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C);
2550  const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : nullptr);
2551 
2552  // Create the confluence block that will "merge" the results of the ternary
2553  // expression.
2554  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2555  appendStmt(ConfluenceBlock, C);
2556  if (badCFG)
2557  return nullptr;
2558 
2559  AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2560 
2561  // Create a block for the LHS expression if there is an LHS expression. A
2562  // GCC extension allows LHS to be NULL, causing the condition to be the
2563  // value that is returned instead.
2564  // e.g: x ?: y is shorthand for: x ? x : y;
2565  Succ = ConfluenceBlock;
2566  Block = nullptr;
2567  CFGBlock *LHSBlock = nullptr;
2568  const Expr *trueExpr = C->getTrueExpr();
2569  if (trueExpr != opaqueValue) {
2570  LHSBlock = Visit(C->getTrueExpr(), alwaysAdd);
2571  if (badCFG)
2572  return nullptr;
2573  Block = nullptr;
2574  }
2575  else
2576  LHSBlock = ConfluenceBlock;
2577 
2578  // Create the block for the RHS expression.
2579  Succ = ConfluenceBlock;
2580  CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd);
2581  if (badCFG)
2582  return nullptr;
2583 
2584  // If the condition is a logical '&&' or '||', build a more accurate CFG.
2585  if (BinaryOperator *Cond =
2586  dyn_cast<BinaryOperator>(C->getCond()->IgnoreParens()))
2587  if (Cond->isLogicalOp())
2588  return VisitLogicalOperator(Cond, C, LHSBlock, RHSBlock).first;
2589 
2590  // Create the block that will contain the condition.
2591  Block = createBlock(false);
2592 
2593  // See if this is a known constant.
2594  const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2595  addSuccessor(Block, LHSBlock, !KnownVal.isFalse());
2596  addSuccessor(Block, RHSBlock, !KnownVal.isTrue());
2597  Block->setTerminator(C);
2598  Expr *condExpr = C->getCond();
2599 
2600  if (opaqueValue) {
2601  // Run the condition expression if it's not trivially expressed in
2602  // terms of the opaque value (or if there is no opaque value).
2603  if (condExpr != opaqueValue)
2604  addStmt(condExpr);
2605 
2606  // Before that, run the common subexpression if there was one.
2607  // At least one of this or the above will be run.
2608  return addStmt(BCO->getCommon());
2609  }
2610 
2611  return addStmt(condExpr);
2612 }
2613 
2614 CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) {
2615  // Check if the Decl is for an __label__. If so, elide it from the
2616  // CFG entirely.
2617  if (isa<LabelDecl>(*DS->decl_begin()))
2618  return Block;
2619 
2620  // This case also handles static_asserts.
2621  if (DS->isSingleDecl())
2622  return VisitDeclSubExpr(DS);
2623 
2624  CFGBlock *B = nullptr;
2625 
2626  // Build an individual DeclStmt for each decl.
2628  E = DS->decl_rend();
2629  I != E; ++I) {
2630  // Get the alignment of the new DeclStmt, padding out to >=8 bytes.
2631  unsigned A = alignof(DeclStmt) < 8 ? 8 : alignof(DeclStmt);
2632 
2633  // Allocate the DeclStmt using the BumpPtrAllocator. It will get
2634  // automatically freed with the CFG.
2635  DeclGroupRef DG(*I);
2636  Decl *D = *I;
2637  void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A);
2638  DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D));
2639  cfg->addSyntheticDeclStmt(DSNew, DS);
2640 
2641  // Append the fake DeclStmt to block.
2642  B = VisitDeclSubExpr(DSNew);
2643  }
2644 
2645  return B;
2646 }
2647 
2648 /// VisitDeclSubExpr - Utility method to add block-level expressions for
2649 /// DeclStmts and initializers in them.
2650 CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) {
2651  assert(DS->isSingleDecl() && "Can handle single declarations only.");
2652  VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl());
2653 
2654  if (!VD) {
2655  // Of everything that can be declared in a DeclStmt, only VarDecls impact
2656  // runtime semantics.
2657  return Block;
2658  }
2659 
2660  bool HasTemporaries = false;
2661 
2662  // Guard static initializers under a branch.
2663  CFGBlock *blockAfterStaticInit = nullptr;
2664 
2665  if (BuildOpts.AddStaticInitBranches && VD->isStaticLocal()) {
2666  // For static variables, we need to create a branch to track
2667  // whether or not they are initialized.
2668  if (Block) {
2669  Succ = Block;
2670  Block = nullptr;
2671  if (badCFG)
2672  return nullptr;
2673  }
2674  blockAfterStaticInit = Succ;
2675  }
2676 
2677  // Destructors of temporaries in initialization expression should be called
2678  // after initialization finishes.
2679  Expr *Init = VD->getInit();
2680  if (Init) {
2681  HasTemporaries = isa<ExprWithCleanups>(Init);
2682 
2683  if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
2684  // Generate destructors for temporaries in initialization expression.
2685  TempDtorContext Context;
2686  VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
2687  /*BindToTemporary=*/false, Context);
2688  }
2689  }
2690 
2691  autoCreateBlock();
2692  appendStmt(Block, DS);
2693 
2694  findConstructionContexts(
2695  ConstructionContextLayer::create(cfg->getBumpVectorContext(), DS),
2696  Init);
2697 
2698  // Keep track of the last non-null block, as 'Block' can be nulled out
2699  // if the initializer expression is something like a 'while' in a
2700  // statement-expression.
2701  CFGBlock *LastBlock = Block;
2702 
2703  if (Init) {
2704  if (HasTemporaries) {
2705  // For expression with temporaries go directly to subexpression to omit
2706  // generating destructors for the second time.
2707  ExprWithCleanups *EC = cast<ExprWithCleanups>(Init);
2708  if (CFGBlock *newBlock = Visit(EC->getSubExpr()))
2709  LastBlock = newBlock;
2710  }
2711  else {
2712  if (CFGBlock *newBlock = Visit(Init))
2713  LastBlock = newBlock;
2714  }
2715  }
2716 
2717  // If the type of VD is a VLA, then we must process its size expressions.
2718  for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr());
2719  VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr())) {
2720  if (CFGBlock *newBlock = addStmt(VA->getSizeExpr()))
2721  LastBlock = newBlock;
2722  }
2723 
2724  maybeAddScopeBeginForVarDecl(Block, VD, DS);
2725 
2726  // Remove variable from local scope.
2727  if (ScopePos && VD == *ScopePos)
2728  ++ScopePos;
2729 
2730  CFGBlock *B = LastBlock;
2731  if (blockAfterStaticInit) {
2732  Succ = B;
2733  Block = createBlock(false);
2734  Block->setTerminator(DS);
2735  addSuccessor(Block, blockAfterStaticInit);
2736  addSuccessor(Block, B);
2737  B = Block;
2738  }
2739 
2740  return B;
2741 }
2742 
2743 CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) {
2744  // We may see an if statement in the middle of a basic block, or it may be the
2745  // first statement we are processing. In either case, we create a new basic
2746  // block. First, we create the blocks for the then...else statements, and
2747  // then we create the block containing the if statement. If we were in the
2748  // middle of a block, we stop processing that block. That block is then the
2749  // implicit successor for the "then" and "else" clauses.
2750 
2751  // Save local scope position because in case of condition variable ScopePos
2752  // won't be restored when traversing AST.
2753  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2754 
2755  // Create local scope for C++17 if init-stmt if one exists.
2756  if (Stmt *Init = I->getInit())
2757  addLocalScopeForStmt(Init);
2758 
2759  // Create local scope for possible condition variable.
2760  // Store scope position. Add implicit destructor.
2761  if (VarDecl *VD = I->getConditionVariable())
2762  addLocalScopeForVarDecl(VD);
2763 
2764  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), I);
2765 
2766  // The block we were processing is now finished. Make it the successor
2767  // block.
2768  if (Block) {
2769  Succ = Block;
2770  if (badCFG)
2771  return nullptr;
2772  }
2773 
2774  // Process the false branch.
2775  CFGBlock *ElseBlock = Succ;
2776 
2777  if (Stmt *Else = I->getElse()) {
2778  SaveAndRestore<CFGBlock*> sv(Succ);
2779 
2780  // NULL out Block so that the recursive call to Visit will
2781  // create a new basic block.
2782  Block = nullptr;
2783 
2784  // If branch is not a compound statement create implicit scope
2785  // and add destructors.
2786  if (!isa<CompoundStmt>(Else))
2787  addLocalScopeAndDtors(Else);
2788 
2789  ElseBlock = addStmt(Else);
2790 
2791  if (!ElseBlock) // Can occur when the Else body has all NullStmts.
2792  ElseBlock = sv.get();
2793  else if (Block) {
2794  if (badCFG)
2795  return nullptr;
2796  }
2797  }
2798 
2799  // Process the true branch.
2800  CFGBlock *ThenBlock;
2801  {
2802  Stmt *Then = I->getThen();
2803  assert(Then);
2804  SaveAndRestore<CFGBlock*> sv(Succ);
2805  Block = nullptr;
2806 
2807  // If branch is not a compound statement create implicit scope
2808  // and add destructors.
2809  if (!isa<CompoundStmt>(Then))
2810  addLocalScopeAndDtors(Then);
2811 
2812  ThenBlock = addStmt(Then);
2813 
2814  if (!ThenBlock) {
2815  // We can reach here if the "then" body has all NullStmts.
2816  // Create an empty block so we can distinguish between true and false
2817  // branches in path-sensitive analyses.
2818  ThenBlock = createBlock(false);
2819  addSuccessor(ThenBlock, sv.get());
2820  } else if (Block) {
2821  if (badCFG)
2822  return nullptr;
2823  }
2824  }
2825 
2826  // Specially handle "if (expr1 || ...)" and "if (expr1 && ...)" by
2827  // having these handle the actual control-flow jump. Note that
2828  // if we introduce a condition variable, e.g. "if (int x = exp1 || exp2)"
2829  // we resort to the old control-flow behavior. This special handling
2830  // removes infeasible paths from the control-flow graph by having the
2831  // control-flow transfer of '&&' or '||' go directly into the then/else
2832  // blocks directly.
2833  BinaryOperator *Cond =
2835  ? nullptr
2836  : dyn_cast<BinaryOperator>(I->getCond()->IgnoreParens());
2837  CFGBlock *LastBlock;
2838  if (Cond && Cond->isLogicalOp())
2839  LastBlock = VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first;
2840  else {
2841  // Now create a new block containing the if statement.
2842  Block = createBlock(false);
2843 
2844  // Set the terminator of the new block to the If statement.
2845  Block->setTerminator(I);
2846 
2847  // See if this is a known constant.
2848  const TryResult &KnownVal = tryEvaluateBool(I->getCond());
2849 
2850  // Add the successors. If we know that specific branches are
2851  // unreachable, inform addSuccessor() of that knowledge.
2852  addSuccessor(Block, ThenBlock, /* isReachable = */ !KnownVal.isFalse());
2853  addSuccessor(Block, ElseBlock, /* isReachable = */ !KnownVal.isTrue());
2854 
2855  // Add the condition as the last statement in the new block. This may
2856  // create new blocks as the condition may contain control-flow. Any newly
2857  // created blocks will be pointed to be "Block".
2858  LastBlock = addStmt(I->getCond());
2859 
2860  // If the IfStmt contains a condition variable, add it and its
2861  // initializer to the CFG.
2862  if (const DeclStmt* DS = I->getConditionVariableDeclStmt()) {
2863  autoCreateBlock();
2864  LastBlock = addStmt(const_cast<DeclStmt *>(DS));
2865  }
2866  }
2867 
2868  // Finally, if the IfStmt contains a C++17 init-stmt, add it to the CFG.
2869  if (Stmt *Init = I->getInit()) {
2870  autoCreateBlock();
2871  LastBlock = addStmt(Init);
2872  }
2873 
2874  return LastBlock;
2875 }
2876 
2877 CFGBlock *CFGBuilder::VisitReturnStmt(ReturnStmt *R) {
2878  // If we were in the middle of a block we stop processing that block.
2879  //
2880  // NOTE: If a "return" appears in the middle of a block, this means that the
2881  // code afterwards is DEAD (unreachable). We still keep a basic block
2882  // for that code; a simple "mark-and-sweep" from the entry block will be
2883  // able to report such dead blocks.
2884 
2885  // Create the new block.
2886  Block = createBlock(false);
2887 
2888  addAutomaticObjHandling(ScopePos, LocalScope::const_iterator(), R);
2889 
2890  findConstructionContexts(
2891  ConstructionContextLayer::create(cfg->getBumpVectorContext(), R),
2892  R->getRetValue());
2893 
2894  // If the one of the destructors does not return, we already have the Exit
2895  // block as a successor.
2896  if (!Block->hasNoReturnElement())
2897  addSuccessor(Block, &cfg->getExit());
2898 
2899  // Add the return statement to the block. This may create new blocks if R
2900  // contains control-flow (short-circuit operations).
2901  return VisitStmt(R, AddStmtChoice::AlwaysAdd);
2902 }
2903 
2904 CFGBlock *CFGBuilder::VisitSEHExceptStmt(SEHExceptStmt *ES) {
2905  // SEHExceptStmt are treated like labels, so they are the first statement in a
2906  // block.
2907 
2908  // Save local scope position because in case of exception variable ScopePos
2909  // won't be restored when traversing AST.
2910  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2911 
2912  addStmt(ES->getBlock());
2913  CFGBlock *SEHExceptBlock = Block;
2914  if (!SEHExceptBlock)
2915  SEHExceptBlock = createBlock();
2916 
2917  appendStmt(SEHExceptBlock, ES);
2918 
2919  // Also add the SEHExceptBlock as a label, like with regular labels.
2920  SEHExceptBlock->setLabel(ES);
2921 
2922  // Bail out if the CFG is bad.
2923  if (badCFG)
2924  return nullptr;
2925 
2926  // We set Block to NULL to allow lazy creation of a new block (if necessary).
2927  Block = nullptr;
2928 
2929  return SEHExceptBlock;
2930 }
2931 
2932 CFGBlock *CFGBuilder::VisitSEHFinallyStmt(SEHFinallyStmt *FS) {
2933  return VisitCompoundStmt(FS->getBlock());
2934 }
2935 
2936 CFGBlock *CFGBuilder::VisitSEHLeaveStmt(SEHLeaveStmt *LS) {
2937  // "__leave" is a control-flow statement. Thus we stop processing the current
2938  // block.
2939  if (badCFG)
2940  return nullptr;
2941 
2942  // Now create a new block that ends with the __leave statement.
2943  Block = createBlock(false);
2944  Block->setTerminator(LS);
2945 
2946  // If there is no target for the __leave, then we are looking at an incomplete
2947  // AST. This means that the CFG cannot be constructed.
2948  if (SEHLeaveJumpTarget.block) {
2949  addAutomaticObjHandling(ScopePos, SEHLeaveJumpTarget.scopePosition, LS);
2950  addSuccessor(Block, SEHLeaveJumpTarget.block);
2951  } else
2952  badCFG = true;
2953 
2954  return Block;
2955 }
2956 
2957 CFGBlock *CFGBuilder::VisitSEHTryStmt(SEHTryStmt *Terminator) {
2958  // "__try"/"__except"/"__finally" is a control-flow statement. Thus we stop
2959  // processing the current block.
2960  CFGBlock *SEHTrySuccessor = nullptr;
2961 
2962  if (Block) {
2963  if (badCFG)
2964  return nullptr;
2965  SEHTrySuccessor = Block;
2966  } else SEHTrySuccessor = Succ;
2967 
2968  // FIXME: Implement __finally support.
2969  if (Terminator->getFinallyHandler())
2970  return NYS();
2971 
2972  CFGBlock *PrevSEHTryTerminatedBlock = TryTerminatedBlock;
2973 
2974  // Create a new block that will contain the __try statement.
2975  CFGBlock *NewTryTerminatedBlock = createBlock(false);
2976 
2977  // Add the terminator in the __try block.
2978  NewTryTerminatedBlock->setTerminator(Terminator);
2979 
2980  if (SEHExceptStmt *Except = Terminator->getExceptHandler()) {
2981  // The code after the try is the implicit successor if there's an __except.
2982  Succ = SEHTrySuccessor;
2983  Block = nullptr;
2984  CFGBlock *ExceptBlock = VisitSEHExceptStmt(Except);
2985  if (!ExceptBlock)
2986  return nullptr;
2987  // Add this block to the list of successors for the block with the try
2988  // statement.
2989  addSuccessor(NewTryTerminatedBlock, ExceptBlock);
2990  }
2991  if (PrevSEHTryTerminatedBlock)
2992  addSuccessor(NewTryTerminatedBlock, PrevSEHTryTerminatedBlock);
2993  else
2994  addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
2995 
2996  // The code after the try is the implicit successor.
2997  Succ = SEHTrySuccessor;
2998 
2999  // Save the current "__try" context.
3000  SaveAndRestore<CFGBlock *> save_try(TryTerminatedBlock,
3001  NewTryTerminatedBlock);
3002  cfg->addTryDispatchBlock(TryTerminatedBlock);
3003 
3004  // Save the current value for the __leave target.
3005  // All __leaves should go to the code following the __try
3006  // (FIXME: or if the __try has a __finally, to the __finally.)
3007  SaveAndRestore<JumpTarget> save_break(SEHLeaveJumpTarget);
3008  SEHLeaveJumpTarget = JumpTarget(SEHTrySuccessor, ScopePos);
3009 
3010  assert(Terminator->getTryBlock() && "__try must contain a non-NULL body");
3011  Block = nullptr;
3012  return addStmt(Terminator->getTryBlock());
3013 }
3014 
3015 CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) {
3016  // Get the block of the labeled statement. Add it to our map.
3017  addStmt(L->getSubStmt());
3018  CFGBlock *LabelBlock = Block;
3019 
3020  if (!LabelBlock) // This can happen when the body is empty, i.e.
3021  LabelBlock = createBlock(); // scopes that only contains NullStmts.
3022 
3023  assert(LabelMap.find(L->getDecl()) == LabelMap.end() &&
3024  "label already in map");
3025  LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos);
3026 
3027  // Labels partition blocks, so this is the end of the basic block we were
3028  // processing (L is the block's label). Because this is label (and we have
3029  // already processed the substatement) there is no extra control-flow to worry
3030  // about.
3031  LabelBlock->setLabel(L);
3032  if (badCFG)
3033  return nullptr;
3034 
3035  // We set Block to NULL to allow lazy creation of a new block (if necessary);
3036  Block = nullptr;
3037 
3038  // This block is now the implicit successor of other blocks.
3039  Succ = LabelBlock;
3040 
3041  return LabelBlock;
3042 }
3043 
3044 CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) {
3045  CFGBlock *LastBlock = VisitNoRecurse(E, asc);
3046  for (const BlockDecl::Capture &CI : E->getBlockDecl()->captures()) {
3047  if (Expr *CopyExpr = CI.getCopyExpr()) {
3048  CFGBlock *Tmp = Visit(CopyExpr);
3049  if (Tmp)
3050  LastBlock = Tmp;
3051  }
3052  }
3053  return LastBlock;
3054 }
3055 
3056 CFGBlock *CFGBuilder::VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc) {
3057  CFGBlock *LastBlock = VisitNoRecurse(E, asc);
3059  et = E->capture_init_end(); it != et; ++it) {
3060  if (Expr *Init = *it) {
3061  CFGBlock *Tmp = Visit(Init);
3062  if (Tmp)
3063  LastBlock = Tmp;
3064  }
3065  }
3066  return LastBlock;
3067 }
3068 
3069 CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) {
3070  // Goto is a control-flow statement. Thus we stop processing the current
3071  // block and create a new one.
3072 
3073  Block = createBlock(false);
3074  Block->setTerminator(G);
3075 
3076  // If we already know the mapping to the label block add the successor now.
3077  LabelMapTy::iterator I = LabelMap.find(G->getLabel());
3078 
3079  if (I == LabelMap.end())
3080  // We will need to backpatch this block later.
3081  BackpatchBlocks.push_back(JumpSource(Block, ScopePos));
3082  else {
3083  JumpTarget JT = I->second;
3084  addAutomaticObjHandling(ScopePos, JT.scopePosition, G);
3085  addSuccessor(Block, JT.block);
3086  }
3087 
3088  return Block;
3089 }
3090 
3091 CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) {
3092  CFGBlock *LoopSuccessor = nullptr;
3093 
3094  // Save local scope position because in case of condition variable ScopePos
3095  // won't be restored when traversing AST.
3096  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3097 
3098  // Create local scope for init statement and possible condition variable.
3099  // Add destructor for init statement and condition variable.
3100  // Store scope position for continue statement.
3101  if (Stmt *Init = F->getInit())
3102  addLocalScopeForStmt(Init);
3103  LocalScope::const_iterator LoopBeginScopePos = ScopePos;
3104 
3105  if (VarDecl *VD = F->getConditionVariable())
3106  addLocalScopeForVarDecl(VD);
3107  LocalScope::const_iterator ContinueScopePos = ScopePos;
3108 
3109  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), F);
3110 
3111  addLoopExit(F);
3112 
3113  // "for" is a control-flow statement. Thus we stop processing the current
3114  // block.
3115  if (Block) {
3116  if (badCFG)
3117  return nullptr;
3118  LoopSuccessor = Block;
3119  } else
3120  LoopSuccessor = Succ;
3121 
3122  // Save the current value for the break targets.
3123  // All breaks should go to the code following the loop.
3124  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3125  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3126 
3127  CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
3128 
3129  // Now create the loop body.
3130  {
3131  assert(F->getBody());
3132 
3133  // Save the current values for Block, Succ, continue and break targets.
3134  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3135  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
3136 
3137  // Create an empty block to represent the transition block for looping back
3138  // to the head of the loop. If we have increment code, it will
3139  // go in this block as well.
3140  Block = Succ = TransitionBlock = createBlock(false);
3141  TransitionBlock->setLoopTarget(F);
3142 
3143  if (Stmt *I = F->getInc()) {
3144  // Generate increment code in its own basic block. This is the target of
3145  // continue statements.
3146  Succ = addStmt(I);
3147  }
3148 
3149  // Finish up the increment (or empty) block if it hasn't been already.
3150  if (Block) {
3151  assert(Block == Succ);
3152  if (badCFG)
3153  return nullptr;
3154  Block = nullptr;
3155  }
3156 
3157  // The starting block for the loop increment is the block that should
3158  // represent the 'loop target' for looping back to the start of the loop.
3159  ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
3160  ContinueJumpTarget.block->setLoopTarget(F);
3161 
3162  // Loop body should end with destructor of Condition variable (if any).
3163  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, F);
3164 
3165  // If body is not a compound statement create implicit scope
3166  // and add destructors.
3167  if (!isa<CompoundStmt>(F->getBody()))
3168  addLocalScopeAndDtors(F->getBody());
3169 
3170  // Now populate the body block, and in the process create new blocks as we
3171  // walk the body of the loop.
3172  BodyBlock = addStmt(F->getBody());
3173 
3174  if (!BodyBlock) {
3175  // In the case of "for (...;...;...);" we can have a null BodyBlock.
3176  // Use the continue jump target as the proxy for the body.
3177  BodyBlock = ContinueJumpTarget.block;
3178  }
3179  else if (badCFG)
3180  return nullptr;
3181  }
3182 
3183  // Because of short-circuit evaluation, the condition of the loop can span
3184  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3185  // evaluate the condition.
3186  CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
3187 
3188  do {
3189  Expr *C = F->getCond();
3190  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3191 
3192  // Specially handle logical operators, which have a slightly
3193  // more optimal CFG representation.
3194  if (BinaryOperator *Cond =
3195  dyn_cast_or_null<BinaryOperator>(C ? C->IgnoreParens() : nullptr))
3196  if (Cond->isLogicalOp()) {
3197  std::tie(EntryConditionBlock, ExitConditionBlock) =
3198  VisitLogicalOperator(Cond, F, BodyBlock, LoopSuccessor);
3199  break;
3200  }
3201 
3202  // The default case when not handling logical operators.
3203  EntryConditionBlock = ExitConditionBlock = createBlock(false);
3204  ExitConditionBlock->setTerminator(F);
3205 
3206  // See if this is a known constant.
3207  TryResult KnownVal(true);
3208 
3209  if (C) {
3210  // Now add the actual condition to the condition block.
3211  // Because the condition itself may contain control-flow, new blocks may
3212  // be created. Thus we update "Succ" after adding the condition.
3213  Block = ExitConditionBlock;
3214  EntryConditionBlock = addStmt(C);
3215 
3216  // If this block contains a condition variable, add both the condition
3217  // variable and initializer to the CFG.
3218  if (VarDecl *VD = F->getConditionVariable()) {
3219  if (Expr *Init = VD->getInit()) {
3220  autoCreateBlock();
3221  const DeclStmt *DS = F->getConditionVariableDeclStmt();
3222  assert(DS->isSingleDecl());
3223  findConstructionContexts(
3224  ConstructionContextLayer::create(cfg->getBumpVectorContext(), DS),
3225  Init);
3226  appendStmt(Block, DS);
3227  EntryConditionBlock = addStmt(Init);
3228  assert(Block == EntryConditionBlock);
3229  maybeAddScopeBeginForVarDecl(EntryConditionBlock, VD, C);
3230  }
3231  }
3232 
3233  if (Block && badCFG)
3234  return nullptr;
3235 
3236  KnownVal = tryEvaluateBool(C);
3237  }
3238 
3239  // Add the loop body entry as a successor to the condition.
3240  addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
3241  // Link up the condition block with the code that follows the loop. (the
3242  // false branch).
3243  addSuccessor(ExitConditionBlock,
3244  KnownVal.isTrue() ? nullptr : LoopSuccessor);
3245  } while (false);
3246 
3247  // Link up the loop-back block to the entry condition block.
3248  addSuccessor(TransitionBlock, EntryConditionBlock);
3249 
3250  // The condition block is the implicit successor for any code above the loop.
3251  Succ = EntryConditionBlock;
3252 
3253  // If the loop contains initialization, create a new block for those
3254  // statements. This block can also contain statements that precede the loop.
3255  if (Stmt *I = F->getInit()) {
3256  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3257  ScopePos = LoopBeginScopePos;
3258  Block = createBlock();
3259  return addStmt(I);
3260  }
3261 
3262  // There is no loop initialization. We are thus basically a while loop.
3263  // NULL out Block to force lazy block construction.
3264  Block = nullptr;
3265  Succ = EntryConditionBlock;
3266  return EntryConditionBlock;
3267 }
3268 
3269 CFGBlock *
3270 CFGBuilder::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *MTE,
3271  AddStmtChoice asc) {
3272  findConstructionContexts(
3273  ConstructionContextLayer::create(cfg->getBumpVectorContext(), MTE),
3274  MTE->getTemporary());
3275 
3276  return VisitStmt(MTE, asc);
3277 }
3278 
3279 CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) {
3280  if (asc.alwaysAdd(*this, M)) {
3281  autoCreateBlock();
3282  appendStmt(Block, M);
3283  }
3284  return Visit(M->getBase());
3285 }
3286 
3287 CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) {
3288  // Objective-C fast enumeration 'for' statements:
3289  // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC
3290  //
3291  // for ( Type newVariable in collection_expression ) { statements }
3292  //
3293  // becomes:
3294  //
3295  // prologue:
3296  // 1. collection_expression
3297  // T. jump to loop_entry
3298  // loop_entry:
3299  // 1. side-effects of element expression
3300  // 1. ObjCForCollectionStmt [performs binding to newVariable]
3301  // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil]
3302  // TB:
3303  // statements
3304  // T. jump to loop_entry
3305  // FB:
3306  // what comes after
3307  //
3308  // and
3309  //
3310  // Type existingItem;
3311  // for ( existingItem in expression ) { statements }
3312  //
3313  // becomes:
3314  //
3315  // the same with newVariable replaced with existingItem; the binding works
3316  // the same except that for one ObjCForCollectionStmt::getElement() returns
3317  // a DeclStmt and the other returns a DeclRefExpr.
3318 
3319  CFGBlock *LoopSuccessor = nullptr;
3320 
3321  if (Block) {
3322  if (badCFG)
3323  return nullptr;
3324  LoopSuccessor = Block;
3325  Block = nullptr;
3326  } else
3327  LoopSuccessor = Succ;
3328 
3329  // Build the condition blocks.
3330  CFGBlock *ExitConditionBlock = createBlock(false);
3331 
3332  // Set the terminator for the "exit" condition block.
3333  ExitConditionBlock->setTerminator(S);
3334 
3335  // The last statement in the block should be the ObjCForCollectionStmt, which
3336  // performs the actual binding to 'element' and determines if there are any
3337  // more items in the collection.
3338  appendStmt(ExitConditionBlock, S);
3339  Block = ExitConditionBlock;
3340 
3341  // Walk the 'element' expression to see if there are any side-effects. We
3342  // generate new blocks as necessary. We DON'T add the statement by default to
3343  // the CFG unless it contains control-flow.
3344  CFGBlock *EntryConditionBlock = Visit(S->getElement(),
3345  AddStmtChoice::NotAlwaysAdd);
3346  if (Block) {
3347  if (badCFG)
3348  return nullptr;
3349  Block = nullptr;
3350  }
3351 
3352  // The condition block is the implicit successor for the loop body as well as
3353  // any code above the loop.
3354  Succ = EntryConditionBlock;
3355 
3356  // Now create the true branch.
3357  {
3358  // Save the current values for Succ, continue and break targets.
3359  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3360  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3361  save_break(BreakJumpTarget);
3362 
3363  // Add an intermediate block between the BodyBlock and the
3364  // EntryConditionBlock to represent the "loop back" transition, for looping
3365  // back to the head of the loop.
3366  CFGBlock *LoopBackBlock = nullptr;
3367  Succ = LoopBackBlock = createBlock();
3368  LoopBackBlock->setLoopTarget(S);
3369 
3370  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3371  ContinueJumpTarget = JumpTarget(Succ, ScopePos);
3372 
3373  CFGBlock *BodyBlock = addStmt(S->getBody());
3374 
3375  if (!BodyBlock)
3376  BodyBlock = ContinueJumpTarget.block; // can happen for "for (X in Y) ;"
3377  else if (Block) {
3378  if (badCFG)
3379  return nullptr;
3380  }
3381 
3382  // This new body block is a successor to our "exit" condition block.
3383  addSuccessor(ExitConditionBlock, BodyBlock);
3384  }
3385 
3386  // Link up the condition block with the code that follows the loop.
3387  // (the false branch).
3388  addSuccessor(ExitConditionBlock, LoopSuccessor);
3389 
3390  // Now create a prologue block to contain the collection expression.
3391  Block = createBlock();
3392  return addStmt(S->getCollection());
3393 }
3394 
3395 CFGBlock *CFGBuilder::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) {
3396  // Inline the body.
3397  return addStmt(S->getSubStmt());
3398  // TODO: consider adding cleanups for the end of @autoreleasepool scope.
3399 }
3400 
3401 CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) {
3402  // FIXME: Add locking 'primitives' to CFG for @synchronized.
3403 
3404  // Inline the body.
3405  CFGBlock *SyncBlock = addStmt(S->getSynchBody());
3406 
3407  // The sync body starts its own basic block. This makes it a little easier
3408  // for diagnostic clients.
3409  if (SyncBlock) {
3410  if (badCFG)
3411  return nullptr;
3412 
3413  Block = nullptr;
3414  Succ = SyncBlock;
3415  }
3416 
3417  // Add the @synchronized to the CFG.
3418  autoCreateBlock();
3419  appendStmt(Block, S);
3420 
3421  // Inline the sync expression.
3422  return addStmt(S->getSynchExpr());
3423 }
3424 
3425 CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) {
3426  // FIXME
3427  return NYS();
3428 }
3429 
3430 CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) {
3431  autoCreateBlock();
3432 
3433  // Add the PseudoObject as the last thing.
3434  appendStmt(Block, E);
3435 
3436  CFGBlock *lastBlock = Block;
3437 
3438  // Before that, evaluate all of the semantics in order. In
3439  // CFG-land, that means appending them in reverse order.
3440  for (unsigned i = E->getNumSemanticExprs(); i != 0; ) {
3441  Expr *Semantic = E->getSemanticExpr(--i);
3442 
3443  // If the semantic is an opaque value, we're being asked to bind
3444  // it to its source expression.
3445  if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
3446  Semantic = OVE->getSourceExpr();
3447 
3448  if (CFGBlock *B = Visit(Semantic))
3449  lastBlock = B;
3450  }
3451 
3452  return lastBlock;
3453 }
3454 
3455 CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) {
3456  CFGBlock *LoopSuccessor = nullptr;
3457 
3458  // Save local scope position because in case of condition variable ScopePos
3459  // won't be restored when traversing AST.
3460  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3461 
3462  // Create local scope for possible condition variable.
3463  // Store scope position for continue statement.
3464  LocalScope::const_iterator LoopBeginScopePos = ScopePos;
3465  if (VarDecl *VD = W->getConditionVariable()) {
3466  addLocalScopeForVarDecl(VD);
3467  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3468  }
3469  addLoopExit(W);
3470 
3471  // "while" is a control-flow statement. Thus we stop processing the current
3472  // block.
3473  if (Block) {
3474  if (badCFG)
3475  return nullptr;
3476  LoopSuccessor = Block;
3477  Block = nullptr;
3478  } else {
3479  LoopSuccessor = Succ;
3480  }
3481 
3482  CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
3483 
3484  // Process the loop body.
3485  {
3486  assert(W->getBody());
3487 
3488  // Save the current values for Block, Succ, continue and break targets.
3489  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3490  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3491  save_break(BreakJumpTarget);
3492 
3493  // Create an empty block to represent the transition block for looping back
3494  // to the head of the loop.
3495  Succ = TransitionBlock = createBlock(false);
3496  TransitionBlock->setLoopTarget(W);
3497  ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos);
3498 
3499  // All breaks should go to the code following the loop.
3500  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3501 
3502  // Loop body should end with destructor of Condition variable (if any).
3503  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3504 
3505  // If body is not a compound statement create implicit scope
3506  // and add destructors.
3507  if (!isa<CompoundStmt>(W->getBody()))
3508  addLocalScopeAndDtors(W->getBody());
3509 
3510  // Create the body. The returned block is the entry to the loop body.
3511  BodyBlock = addStmt(W->getBody());
3512 
3513  if (!BodyBlock)
3514  BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;"
3515  else if (Block && badCFG)
3516  return nullptr;
3517  }
3518 
3519  // Because of short-circuit evaluation, the condition of the loop can span
3520  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3521  // evaluate the condition.
3522  CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
3523 
3524  do {
3525  Expr *C = W->getCond();
3526 
3527  // Specially handle logical operators, which have a slightly
3528  // more optimal CFG representation.
3529  if (BinaryOperator *Cond = dyn_cast<BinaryOperator>(C->IgnoreParens()))
3530  if (Cond->isLogicalOp()) {
3531  std::tie(EntryConditionBlock, ExitConditionBlock) =
3532  VisitLogicalOperator(Cond, W, BodyBlock, LoopSuccessor);
3533  break;
3534  }
3535 
3536  // The default case when not handling logical operators.
3537  ExitConditionBlock = createBlock(false);
3538  ExitConditionBlock->setTerminator(W);
3539 
3540  // Now add the actual condition to the condition block.
3541  // Because the condition itself may contain control-flow, new blocks may
3542  // be created. Thus we update "Succ" after adding the condition.
3543  Block = ExitConditionBlock;
3544  Block = EntryConditionBlock = addStmt(C);
3545 
3546  // If this block contains a condition variable, add both the condition
3547  // variable and initializer to the CFG.
3548  if (VarDecl *VD = W->getConditionVariable()) {
3549  if (Expr *Init = VD->getInit()) {
3550  autoCreateBlock();
3551  const DeclStmt *DS = W->getConditionVariableDeclStmt();
3552  assert(DS->isSingleDecl());
3553  findConstructionContexts(
3554  ConstructionContextLayer::create(cfg->getBumpVectorContext(),
3555  const_cast<DeclStmt *>(DS)),
3556  Init);
3557  appendStmt(Block, DS);
3558  EntryConditionBlock = addStmt(Init);
3559  assert(Block == EntryConditionBlock);
3560  maybeAddScopeBeginForVarDecl(EntryConditionBlock, VD, C);
3561  }
3562  }
3563 
3564  if (Block && badCFG)
3565  return nullptr;
3566 
3567  // See if this is a known constant.
3568  const TryResult& KnownVal = tryEvaluateBool(C);
3569 
3570  // Add the loop body entry as a successor to the condition.
3571  addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
3572  // Link up the condition block with the code that follows the loop. (the
3573  // false branch).
3574  addSuccessor(ExitConditionBlock,
3575  KnownVal.isTrue() ? nullptr : LoopSuccessor);
3576  } while(false);
3577 
3578  // Link up the loop-back block to the entry condition block.
3579  addSuccessor(TransitionBlock, EntryConditionBlock);
3580 
3581  // There can be no more statements in the condition block since we loop back
3582  // to this block. NULL out Block to force lazy creation of another block.
3583  Block = nullptr;
3584 
3585  // Return the condition block, which is the dominating block for the loop.
3586  Succ = EntryConditionBlock;
3587  return EntryConditionBlock;
3588 }
3589 
3590 CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) {
3591  // FIXME: For now we pretend that @catch and the code it contains does not
3592  // exit.
3593  return Block;
3594 }
3595 
3596 CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) {
3597  // FIXME: This isn't complete. We basically treat @throw like a return
3598  // statement.
3599 
3600  // If we were in the middle of a block we stop processing that block.
3601  if (badCFG)
3602  return nullptr;
3603 
3604  // Create the new block.
3605  Block = createBlock(false);
3606 
3607  // The Exit block is the only successor.
3608  addSuccessor(Block, &cfg->getExit());
3609 
3610  // Add the statement to the block. This may create new blocks if S contains
3611  // control-flow (short-circuit operations).
3612  return VisitStmt(S, AddStmtChoice::AlwaysAdd);
3613 }
3614 
3615 CFGBlock *CFGBuilder::VisitObjCMessageExpr(ObjCMessageExpr *ME,
3616  AddStmtChoice asc) {
3617  findConstructionContextsForArguments(ME);
3618 
3619  autoCreateBlock();
3620  appendObjCMessage(Block, ME);
3621 
3622  return VisitChildren(ME);
3623 }
3624 
3625 CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) {
3626  // If we were in the middle of a block we stop processing that block.
3627  if (badCFG)
3628  return nullptr;
3629 
3630  // Create the new block.
3631  Block = createBlock(false);
3632 
3633  if (TryTerminatedBlock)
3634  // The current try statement is the only successor.
3635  addSuccessor(Block, TryTerminatedBlock);
3636  else
3637  // otherwise the Exit block is the only successor.
3638  addSuccessor(Block, &cfg->getExit());
3639 
3640  // Add the statement to the block. This may create new blocks if S contains
3641  // control-flow (short-circuit operations).
3642  return VisitStmt(T, AddStmtChoice::AlwaysAdd);
3643 }
3644 
3645 CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) {
3646  CFGBlock *LoopSuccessor = nullptr;
3647 
3648  addLoopExit(D);
3649 
3650  // "do...while" is a control-flow statement. Thus we stop processing the
3651  // current block.
3652  if (Block) {
3653  if (badCFG)
3654  return nullptr;
3655  LoopSuccessor = Block;
3656  } else
3657  LoopSuccessor = Succ;
3658 
3659  // Because of short-circuit evaluation, the condition of the loop can span
3660  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3661  // evaluate the condition.
3662  CFGBlock *ExitConditionBlock = createBlock(false);
3663  CFGBlock *EntryConditionBlock = ExitConditionBlock;
3664 
3665  // Set the terminator for the "exit" condition block.
3666  ExitConditionBlock->setTerminator(D);
3667 
3668  // Now add the actual condition to the condition block. Because the condition
3669  // itself may contain control-flow, new blocks may be created.
3670  if (Stmt *C = D->getCond()) {
3671  Block = ExitConditionBlock;
3672  EntryConditionBlock = addStmt(C);
3673  if (Block) {
3674  if (badCFG)
3675  return nullptr;
3676  }
3677  }
3678 
3679  // The condition block is the implicit successor for the loop body.
3680  Succ = EntryConditionBlock;
3681 
3682  // See if this is a known constant.
3683  const TryResult &KnownVal = tryEvaluateBool(D->getCond());
3684 
3685  // Process the loop body.
3686  CFGBlock *BodyBlock = nullptr;
3687  {
3688  assert(D->getBody());
3689 
3690  // Save the current values for Block, Succ, and continue and break targets
3691  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3692  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3693  save_break(BreakJumpTarget);
3694 
3695  // All continues within this loop should go to the condition block
3696  ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos);
3697 
3698  // All breaks should go to the code following the loop.
3699  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3700 
3701  // NULL out Block to force lazy instantiation of blocks for the body.
3702  Block = nullptr;
3703 
3704  // If body is not a compound statement create implicit scope
3705  // and add destructors.
3706  if (!isa<CompoundStmt>(D->getBody()))
3707  addLocalScopeAndDtors(D->getBody());
3708 
3709  // Create the body. The returned block is the entry to the loop body.
3710  BodyBlock = addStmt(D->getBody());
3711 
3712  if (!BodyBlock)
3713  BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)"
3714  else if (Block) {
3715  if (badCFG)
3716  return nullptr;
3717  }
3718 
3719  // Add an intermediate block between the BodyBlock and the
3720  // ExitConditionBlock to represent the "loop back" transition. Create an
3721  // empty block to represent the transition block for looping back to the
3722  // head of the loop.
3723  // FIXME: Can we do this more efficiently without adding another block?
3724  Block = nullptr;
3725  Succ = BodyBlock;
3726  CFGBlock *LoopBackBlock = createBlock();
3727  LoopBackBlock->setLoopTarget(D);
3728 
3729  if (!KnownVal.isFalse())
3730  // Add the loop body entry as a successor to the condition.
3731  addSuccessor(ExitConditionBlock, LoopBackBlock);
3732  else
3733  addSuccessor(ExitConditionBlock, nullptr);
3734  }
3735 
3736  // Link up the condition block with the code that follows the loop.
3737  // (the false branch).
3738  addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
3739 
3740  // There can be no more statements in the body block(s) since we loop back to
3741  // the body. NULL out Block to force lazy creation of another block.
3742  Block = nullptr;
3743 
3744  // Return the loop body, which is the dominating block for the loop.
3745  Succ = BodyBlock;
3746  return BodyBlock;
3747 }
3748 
3749 CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) {
3750  // "continue" is a control-flow statement. Thus we stop processing the
3751  // current block.
3752  if (badCFG)
3753  return nullptr;
3754 
3755  // Now create a new block that ends with the continue statement.
3756  Block = createBlock(false);
3757  Block->setTerminator(C);
3758 
3759  // If there is no target for the continue, then we are looking at an
3760  // incomplete AST. This means the CFG cannot be constructed.
3761  if (ContinueJumpTarget.block) {
3762  addAutomaticObjHandling(ScopePos, ContinueJumpTarget.scopePosition, C);
3763  addSuccessor(Block, ContinueJumpTarget.block);
3764  } else
3765  badCFG = true;
3766 
3767  return Block;
3768 }
3769 
3770 CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
3771  AddStmtChoice asc) {
3772  if (asc.alwaysAdd(*this, E)) {
3773  autoCreateBlock();
3774  appendStmt(Block, E);
3775  }
3776 
3777  // VLA types have expressions that must be evaluated.
3778  CFGBlock *lastBlock = Block;
3779 
3780  if (E->isArgumentType()) {
3781  for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr());
3782  VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr()))
3783  lastBlock = addStmt(VA->getSizeExpr());
3784  }
3785  return lastBlock;
3786 }
3787 
3788 /// VisitStmtExpr - Utility method to handle (nested) statement
3789 /// expressions (a GCC extension).
3790 CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) {
3791  if (asc.alwaysAdd(*this, SE)) {
3792  autoCreateBlock();
3793  appendStmt(Block, SE);
3794  }
3795  return VisitCompoundStmt(SE->getSubStmt());
3796 }
3797 
3798 CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) {
3799  // "switch" is a control-flow statement. Thus we stop processing the current
3800  // block.
3801  CFGBlock *SwitchSuccessor = nullptr;
3802 
3803  // Save local scope position because in case of condition variable ScopePos
3804  // won't be restored when traversing AST.
3805  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3806 
3807  // Create local scope for C++17 switch init-stmt if one exists.
3808  if (Stmt *Init = Terminator->getInit())
3809  addLocalScopeForStmt(Init);
3810 
3811  // Create local scope for possible condition variable.
3812  // Store scope position. Add implicit destructor.
3813  if (VarDecl *VD = Terminator->getConditionVariable())
3814  addLocalScopeForVarDecl(VD);
3815 
3816  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), Terminator);
3817 
3818  if (Block) {
3819  if (badCFG)
3820  return nullptr;
3821  SwitchSuccessor = Block;
3822  } else SwitchSuccessor = Succ;
3823 
3824  // Save the current "switch" context.
3825  SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock),
3826  save_default(DefaultCaseBlock);
3827  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3828 
3829  // Set the "default" case to be the block after the switch statement. If the
3830  // switch statement contains a "default:", this value will be overwritten with
3831  // the block for that code.
3832  DefaultCaseBlock = SwitchSuccessor;
3833 
3834  // Create a new block that will contain the switch statement.
3835  SwitchTerminatedBlock = createBlock(false);
3836 
3837  // Now process the switch body. The code after the switch is the implicit
3838  // successor.
3839  Succ = SwitchSuccessor;
3840  BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos);
3841 
3842  // When visiting the body, the case statements should automatically get linked
3843  // up to the switch. We also don't keep a pointer to the body, since all
3844  // control-flow from the switch goes to case/default statements.
3845  assert(Terminator->getBody() && "switch must contain a non-NULL body");
3846  Block = nullptr;
3847 
3848  // For pruning unreachable case statements, save the current state
3849  // for tracking the condition value.
3850  SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered,
3851  false);
3852 
3853  // Determine if the switch condition can be explicitly evaluated.
3854  assert(Terminator->getCond() && "switch condition must be non-NULL");
3855  Expr::EvalResult result;
3856  bool b = tryEvaluate(Terminator->getCond(), result);
3857  SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond,
3858  b ? &result : nullptr);
3859 
3860  // If body is not a compound statement create implicit scope
3861  // and add destructors.
3862  if (!isa<CompoundStmt>(Terminator->getBody()))
3863  addLocalScopeAndDtors(Terminator->getBody());
3864 
3865  addStmt(Terminator->getBody());
3866  if (Block) {
3867  if (badCFG)
3868  return nullptr;
3869  }
3870 
3871  // If we have no "default:" case, the default transition is to the code
3872  // following the switch body. Moreover, take into account if all the
3873  // cases of a switch are covered (e.g., switching on an enum value).
3874  //
3875  // Note: We add a successor to a switch that is considered covered yet has no
3876  // case statements if the enumeration has no enumerators.
3877  bool SwitchAlwaysHasSuccessor = false;
3878  SwitchAlwaysHasSuccessor |= switchExclusivelyCovered;
3879  SwitchAlwaysHasSuccessor |= Terminator->isAllEnumCasesCovered() &&
3880  Terminator->getSwitchCaseList();
3881  addSuccessor(SwitchTerminatedBlock, DefaultCaseBlock,
3882  !SwitchAlwaysHasSuccessor);
3883 
3884  // Add the terminator and condition in the switch block.
3885  SwitchTerminatedBlock->setTerminator(Terminator);
3886  Block = SwitchTerminatedBlock;
3887  CFGBlock *LastBlock = addStmt(Terminator->getCond());
3888 
3889  // If the SwitchStmt contains a condition variable, add both the
3890  // SwitchStmt and the condition variable initialization to the CFG.
3891  if (VarDecl *VD = Terminator->getConditionVariable()) {
3892  if (Expr *Init = VD->getInit()) {
3893  autoCreateBlock();
3894  appendStmt(Block, Terminator->getConditionVariableDeclStmt());
3895  LastBlock = addStmt(Init);
3896  maybeAddScopeBeginForVarDecl(LastBlock, VD, Init);
3897  }
3898  }
3899 
3900  // Finally, if the SwitchStmt contains a C++17 init-stmt, add it to the CFG.
3901  if (Stmt *Init = Terminator->getInit()) {
3902  autoCreateBlock();
3903  LastBlock = addStmt(Init);
3904  }
3905 
3906  return LastBlock;
3907 }
3908 
3909 static bool shouldAddCase(bool &switchExclusivelyCovered,
3910  const Expr::EvalResult *switchCond,
3911  const CaseStmt *CS,
3912  ASTContext &Ctx) {
3913  if (!switchCond)
3914  return true;
3915 
3916  bool addCase = false;
3917 
3918  if (!switchExclusivelyCovered) {
3919  if (switchCond->Val.isInt()) {
3920  // Evaluate the LHS of the case value.
3921  const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx);
3922  const llvm::APSInt &condInt = switchCond->Val.getInt();
3923 
3924  if (condInt == lhsInt) {
3925  addCase = true;
3926  switchExclusivelyCovered = true;
3927  }
3928  else if (condInt > lhsInt) {
3929  if (const Expr *RHS = CS->getRHS()) {
3930  // Evaluate the RHS of the case value.
3931  const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx);
3932  if (V2 >= condInt) {
3933  addCase = true;
3934  switchExclusivelyCovered = true;
3935  }
3936  }
3937  }
3938  }
3939  else
3940  addCase = true;
3941  }
3942  return addCase;
3943 }
3944 
3945 CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) {
3946  // CaseStmts are essentially labels, so they are the first statement in a
3947  // block.
3948  CFGBlock *TopBlock = nullptr, *LastBlock = nullptr;
3949 
3950  if (Stmt *Sub = CS->getSubStmt()) {
3951  // For deeply nested chains of CaseStmts, instead of doing a recursion
3952  // (which can blow out the stack), manually unroll and create blocks
3953  // along the way.
3954  while (isa<CaseStmt>(Sub)) {
3955  CFGBlock *currentBlock = createBlock(false);
3956  currentBlock->setLabel(CS);
3957 
3958  if (TopBlock)
3959  addSuccessor(LastBlock, currentBlock);
3960  else
3961  TopBlock = currentBlock;
3962 
3963  addSuccessor(SwitchTerminatedBlock,
3964  shouldAddCase(switchExclusivelyCovered, switchCond,
3965  CS, *Context)
3966  ? currentBlock : nullptr);
3967 
3968  LastBlock = currentBlock;
3969  CS = cast<CaseStmt>(Sub);
3970  Sub = CS->getSubStmt();
3971  }
3972 
3973  addStmt(Sub);
3974  }
3975 
3976  CFGBlock *CaseBlock = Block;
3977  if (!CaseBlock)
3978  CaseBlock = createBlock();
3979 
3980  // Cases statements partition blocks, so this is the top of the basic block we
3981  // were processing (the "case XXX:" is the label).
3982  CaseBlock->setLabel(CS);
3983 
3984  if (badCFG)
3985  return nullptr;
3986 
3987  // Add this block to the list of successors for the block with the switch
3988  // statement.
3989  assert(SwitchTerminatedBlock);
3990  addSuccessor(SwitchTerminatedBlock, CaseBlock,
3991  shouldAddCase(switchExclusivelyCovered, switchCond,
3992  CS, *Context));
3993 
3994  // We set Block to NULL to allow lazy creation of a new block (if necessary)
3995  Block = nullptr;
3996 
3997  if (TopBlock) {
3998  addSuccessor(LastBlock, CaseBlock);
3999  Succ = TopBlock;
4000  } else {
4001  // This block is now the implicit successor of other blocks.
4002  Succ = CaseBlock;
4003  }
4004 
4005  return Succ;
4006 }
4007 
4008 CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) {
4009  if (Terminator->getSubStmt())
4010  addStmt(Terminator->getSubStmt());
4011 
4012  DefaultCaseBlock = Block;
4013 
4014  if (!DefaultCaseBlock)
4015  DefaultCaseBlock = createBlock();
4016 
4017  // Default statements partition blocks, so this is the top of the basic block
4018  // we were processing (the "default:" is the label).
4019  DefaultCaseBlock->setLabel(Terminator);
4020 
4021  if (badCFG)
4022  return nullptr;
4023 
4024  // Unlike case statements, we don't add the default block to the successors
4025  // for the switch statement immediately. This is done when we finish
4026  // processing the switch statement. This allows for the default case
4027  // (including a fall-through to the code after the switch statement) to always
4028  // be the last successor of a switch-terminated block.
4029 
4030  // We set Block to NULL to allow lazy creation of a new block (if necessary)
4031  Block = nullptr;
4032 
4033  // This block is now the implicit successor of other blocks.
4034  Succ = DefaultCaseBlock;
4035 
4036  return DefaultCaseBlock;
4037 }
4038 
4039 CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) {
4040  // "try"/"catch" is a control-flow statement. Thus we stop processing the
4041  // current block.
4042  CFGBlock *TrySuccessor = nullptr;
4043 
4044  if (Block) {
4045  if (badCFG)
4046  return nullptr;
4047  TrySuccessor = Block;
4048  } else TrySuccessor = Succ;
4049 
4050  CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock;
4051 
4052  // Create a new block that will contain the try statement.
4053  CFGBlock *NewTryTerminatedBlock = createBlock(false);
4054  // Add the terminator in the try block.
4055  NewTryTerminatedBlock->setTerminator(Terminator);
4056 
4057  bool HasCatchAll = false;
4058  for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) {
4059  // The code after the try is the implicit successor.
4060  Succ = TrySuccessor;
4061  CXXCatchStmt *CS = Terminator->getHandler(h);
4062  if (CS->getExceptionDecl() == nullptr) {
4063  HasCatchAll = true;
4064  }
4065  Block = nullptr;
4066  CFGBlock *CatchBlock = VisitCXXCatchStmt(CS);
4067  if (!CatchBlock)
4068  return nullptr;
4069  // Add this block to the list of successors for the block with the try
4070  // statement.
4071  addSuccessor(NewTryTerminatedBlock, CatchBlock);
4072  }
4073  if (!HasCatchAll) {
4074  if (PrevTryTerminatedBlock)
4075  addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock);
4076  else
4077  addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
4078  }
4079 
4080  // The code after the try is the implicit successor.
4081  Succ = TrySuccessor;
4082 
4083  // Save the current "try" context.
4084  SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock);
4085  cfg->addTryDispatchBlock(TryTerminatedBlock);
4086 
4087  assert(Terminator->getTryBlock() && "try must contain a non-NULL body");
4088  Block = nullptr;
4089  return addStmt(Terminator->getTryBlock());
4090 }
4091 
4092 CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) {
4093  // CXXCatchStmt are treated like labels, so they are the first statement in a
4094  // block.
4095 
4096  // Save local scope position because in case of exception variable ScopePos
4097  // won't be restored when traversing AST.
4098  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
4099 
4100  // Create local scope for possible exception variable.
4101  // Store scope position. Add implicit destructor.
4102  if (VarDecl *VD = CS->getExceptionDecl()) {
4103  LocalScope::const_iterator BeginScopePos = ScopePos;
4104  addLocalScopeForVarDecl(VD);
4105  addAutomaticObjHandling(ScopePos, BeginScopePos, CS);
4106  }
4107 
4108  if (CS->getHandlerBlock())
4109  addStmt(CS->getHandlerBlock());
4110 
4111  CFGBlock *CatchBlock = Block;
4112  if (!CatchBlock)
4113  CatchBlock = createBlock();
4114 
4115  // CXXCatchStmt is more than just a label. They have semantic meaning
4116  // as well, as they implicitly "initialize" the catch variable. Add
4117  // it to the CFG as a CFGElement so that the control-flow of these
4118  // semantics gets captured.
4119  appendStmt(CatchBlock, CS);
4120 
4121  // Also add the CXXCatchStmt as a label, to mirror handling of regular
4122  // labels.
4123  CatchBlock->setLabel(CS);
4124 
4125  // Bail out if the CFG is bad.
4126  if (badCFG)
4127  return nullptr;
4128 
4129  // We set Block to NULL to allow lazy creation of a new block (if necessary)
4130  Block = nullptr;
4131 
4132  return CatchBlock;
4133 }
4134 
4135 CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) {
4136  // C++0x for-range statements are specified as [stmt.ranged]:
4137  //
4138  // {
4139  // auto && __range = range-init;
4140  // for ( auto __begin = begin-expr,
4141  // __end = end-expr;
4142  // __begin != __end;
4143  // ++__begin ) {
4144  // for-range-declaration = *__begin;
4145  // statement
4146  // }
4147  // }
4148 
4149  // Save local scope position before the addition of the implicit variables.
4150  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
4151 
4152  // Create local scopes and destructors for range, begin and end variables.
4153  if (Stmt *Range = S->getRangeStmt())
4154  addLocalScopeForStmt(Range);
4155  if (Stmt *Begin = S->getBeginStmt())
4156  addLocalScopeForStmt(Begin);
4157  if (Stmt *End = S->getEndStmt())
4158  addLocalScopeForStmt(End);
4159  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), S);
4160 
4161  LocalScope::const_iterator ContinueScopePos = ScopePos;
4162 
4163  // "for" is a control-flow statement. Thus we stop processing the current
4164  // block.
4165  CFGBlock *LoopSuccessor = nullptr;
4166  if (Block) {
4167  if (badCFG)
4168  return nullptr;
4169  LoopSuccessor = Block;
4170  } else
4171  LoopSuccessor = Succ;
4172 
4173  // Save the current value for the break targets.
4174  // All breaks should go to the code following the loop.
4175  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
4176  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
4177 
4178  // The block for the __begin != __end expression.
4179  CFGBlock *ConditionBlock = createBlock(false);
4180  ConditionBlock->setTerminator(S);
4181 
4182  // Now add the actual condition to the condition block.
4183  if (Expr *C = S->getCond()) {
4184  Block = ConditionBlock;
4185  CFGBlock *BeginConditionBlock = addStmt(C);
4186  if (badCFG)
4187  return nullptr;
4188  assert(BeginConditionBlock == ConditionBlock &&
4189  "condition block in for-range was unexpectedly complex");
4190  (void)BeginConditionBlock;
4191  }
4192 
4193  // The condition block is the implicit successor for the loop body as well as
4194  // any code above the loop.
4195  Succ = ConditionBlock;
4196 
4197  // See if this is a known constant.
4198  TryResult KnownVal(true);
4199 
4200  if (S->getCond())
4201  KnownVal = tryEvaluateBool(S->getCond());
4202 
4203  // Now create the loop body.
4204  {
4205  assert(S->getBody());
4206 
4207  // Save the current values for Block, Succ, and continue targets.
4208  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
4209  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
4210 
4211  // Generate increment code in its own basic block. This is the target of
4212  // continue statements.
4213  Block = nullptr;
4214  Succ = addStmt(S->getInc());
4215  if (badCFG)
4216  return nullptr;
4217  ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
4218 
4219  // The starting block for the loop increment is the block that should
4220  // represent the 'loop target' for looping back to the start of the loop.
4221  ContinueJumpTarget.block->setLoopTarget(S);
4222 
4223  // Finish up the increment block and prepare to start the loop body.
4224  assert(Block);
4225  if (badCFG)
4226  return nullptr;
4227  Block = nullptr;
4228 
4229  // Add implicit scope and dtors for loop variable.
4230  addLocalScopeAndDtors(S->getLoopVarStmt());
4231 
4232  // Populate a new block to contain the loop body and loop variable.
4233  addStmt(S->getBody());
4234  if (badCFG)
4235  return nullptr;
4236  CFGBlock *LoopVarStmtBlock = addStmt(S->getLoopVarStmt());
4237  if (badCFG)
4238  return nullptr;
4239 
4240  // This new body block is a successor to our condition block.
4241  addSuccessor(ConditionBlock,
4242  KnownVal.isFalse() ? nullptr : LoopVarStmtBlock);
4243  }
4244 
4245  // Link up the condition block with the code that follows the loop (the
4246  // false branch).
4247  addSuccessor(ConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
4248 
4249  // Add the initialization statements.
4250  Block = createBlock();
4251  addStmt(S->getBeginStmt());
4252  addStmt(S->getEndStmt());
4253  return addStmt(S->getRangeStmt());
4254 }
4255 
4256 CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E,
4257  AddStmtChoice asc) {
4258  if (BuildOpts.AddTemporaryDtors) {
4259  // If adding implicit destructors visit the full expression for adding
4260  // destructors of temporaries.
4261  TempDtorContext Context;
4262  VisitForTemporaryDtors(E->getSubExpr(), false, Context);
4263 
4264  // Full expression has to be added as CFGStmt so it will be sequenced
4265  // before destructors of it's temporaries.
4266  asc = asc.withAlwaysAdd(true);
4267  }
4268  return Visit(E->getSubExpr(), asc);
4269 }
4270 
4271 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
4272  AddStmtChoice asc) {
4273  if (asc.alwaysAdd(*this, E)) {
4274  autoCreateBlock();
4275  appendStmt(Block, E);
4276 
4277  findConstructionContexts(
4278  ConstructionContextLayer::create(cfg->getBumpVectorContext(), E),
4279  E->getSubExpr());
4280 
4281  // We do not want to propagate the AlwaysAdd property.
4282  asc = asc.withAlwaysAdd(false);
4283  }
4284  return Visit(E->getSubExpr(), asc);
4285 }
4286 
4287 CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C,
4288  AddStmtChoice asc) {
4289  // If the constructor takes objects as arguments by value, we need to properly
4290  // construct these objects. Construction contexts we find here aren't for the
4291  // constructor C, they're for its arguments only.
4292  findConstructionContextsForArguments(C);
4293 
4294  autoCreateBlock();
4295  appendConstructor(Block, C);
4296 
4297  return VisitChildren(C);
4298 }
4299 
4300 CFGBlock *CFGBuilder::VisitCXXNewExpr(CXXNewExpr *NE,
4301  AddStmtChoice asc) {
4302  autoCreateBlock();
4303  appendStmt(Block, NE);
4304 
4305  findConstructionContexts(
4306  ConstructionContextLayer::create(cfg->getBumpVectorContext(), NE),
4307  const_cast<CXXConstructExpr *>(NE->getConstructExpr()));
4308 
4309  if (NE->getInitializer())
4310  Block = Visit(NE->getInitializer());
4311 
4312  if (BuildOpts.AddCXXNewAllocator)
4313  appendNewAllocator(Block, NE);
4314 
4315  if (NE->isArray())
4316  Block = Visit(NE->getArraySize());
4317 
4319  E = NE->placement_arg_end(); I != E; ++I)
4320  Block = Visit(*I);
4321 
4322  return Block;
4323 }
4324 
4325 CFGBlock *CFGBuilder::VisitCXXDeleteExpr(CXXDeleteExpr *DE,
4326  AddStmtChoice asc) {
4327  autoCreateBlock();
4328  appendStmt(Block, DE);
4329  QualType DTy = DE->getDestroyedType();
4330  if (!DTy.isNull()) {
4331  DTy = DTy.getNonReferenceType();
4332  CXXRecordDecl *RD = Context->getBaseElementType(DTy)->getAsCXXRecordDecl();
4333  if (RD) {
4334  if (RD->isCompleteDefinition() && !RD->hasTrivialDestructor())
4335  appendDeleteDtor(Block, RD, DE);
4336  }
4337  }
4338 
4339  return VisitChildren(DE);
4340 }
4341 
4342 CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
4343  AddStmtChoice asc) {
4344  if (asc.alwaysAdd(*this, E)) {
4345  autoCreateBlock();
4346  appendStmt(Block, E);
4347  // We do not want to propagate the AlwaysAdd property.
4348  asc = asc.withAlwaysAdd(false);
4349  }
4350  return Visit(E->getSubExpr(), asc);
4351 }
4352 
4353 CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
4354  AddStmtChoice asc) {
4355  // If the constructor takes objects as arguments by value, we need to properly
4356  // construct these objects. Construction contexts we find here aren't for the
4357  // constructor C, they're for its arguments only.
4358  findConstructionContextsForArguments(C);
4359 
4360  autoCreateBlock();
4361  appendConstructor(Block, C);
4362  return VisitChildren(C);
4363 }
4364 
4365 CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E,
4366  AddStmtChoice asc) {
4367  if (asc.alwaysAdd(*this, E)) {
4368  autoCreateBlock();
4369  appendStmt(Block, E);
4370  }
4371  return Visit(E->getSubExpr(), AddStmtChoice());
4372 }
4373 
4374 CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) {
4375  // Lazily create the indirect-goto dispatch block if there isn't one already.
4376  CFGBlock *IBlock = cfg->getIndirectGotoBlock();
4377 
4378  if (!IBlock) {
4379  IBlock = createBlock(false);
4380  cfg->setIndirectGotoBlock(IBlock);
4381  }
4382 
4383  // IndirectGoto is a control-flow statement. Thus we stop processing the
4384  // current block and create a new one.
4385  if (badCFG)
4386  return nullptr;
4387 
4388  Block = createBlock(false);
4389  Block->setTerminator(I);
4390  addSuccessor(Block, IBlock);
4391  return addStmt(I->getTarget());
4392 }
4393 
4394 CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary,
4395  TempDtorContext &Context) {
4396  assert(BuildOpts.AddImplicitDtors && BuildOpts.AddTemporaryDtors);
4397 
4398 tryAgain:
4399  if (!E) {
4400  badCFG = true;
4401  return nullptr;
4402  }
4403  switch (E->getStmtClass()) {
4404  default:
4405  return VisitChildrenForTemporaryDtors(E, Context);
4406 
4407  case Stmt::BinaryOperatorClass:
4408  return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E),
4409  Context);
4410 
4411  case Stmt::CXXBindTemporaryExprClass:
4412  return VisitCXXBindTemporaryExprForTemporaryDtors(
4413  cast<CXXBindTemporaryExpr>(E), BindToTemporary, Context);
4414 
4415  case Stmt::BinaryConditionalOperatorClass:
4416  case Stmt::ConditionalOperatorClass:
4417  return VisitConditionalOperatorForTemporaryDtors(
4418  cast<AbstractConditionalOperator>(E), BindToTemporary, Context);
4419 
4420  case Stmt::ImplicitCastExprClass:
4421  // For implicit cast we want BindToTemporary to be passed further.
4422  E = cast<CastExpr>(E)->getSubExpr();
4423  goto tryAgain;
4424 
4425  case Stmt::CXXFunctionalCastExprClass:
4426  // For functional cast we want BindToTemporary to be passed further.
4427  E = cast<CXXFunctionalCastExpr>(E)->getSubExpr();
4428  goto tryAgain;
4429 
4430  case Stmt::ParenExprClass:
4431  E = cast<ParenExpr>(E)->getSubExpr();
4432  goto tryAgain;
4433 
4434  case Stmt::MaterializeTemporaryExprClass: {
4435  const MaterializeTemporaryExpr* MTE = cast<MaterializeTemporaryExpr>(E);
4436  BindToTemporary = (MTE->getStorageDuration() != SD_FullExpression);
4437  SmallVector<const Expr *, 2> CommaLHSs;
4439  // Find the expression whose lifetime needs to be extended.
4440  E = const_cast<Expr *>(
4441  cast<MaterializeTemporaryExpr>(E)
4442  ->GetTemporaryExpr()
4443  ->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments));
4444  // Visit the skipped comma operator left-hand sides for other temporaries.
4445  for (const Expr *CommaLHS : CommaLHSs) {
4446  VisitForTemporaryDtors(const_cast<Expr *>(CommaLHS),
4447  /*BindToTemporary=*/false, Context);
4448  }
4449  goto tryAgain;
4450  }
4451 
4452  case Stmt::BlockExprClass:
4453  // Don't recurse into blocks; their subexpressions don't get evaluated
4454  // here.
4455  return Block;
4456 
4457  case Stmt::LambdaExprClass: {
4458  // For lambda expressions, only recurse into the capture initializers,
4459  // and not the body.
4460  auto *LE = cast<LambdaExpr>(E);
4461  CFGBlock *B = Block;
4462  for (Expr *Init : LE->capture_inits()) {
4463  if (Init) {
4464  if (CFGBlock *R = VisitForTemporaryDtors(
4465  Init, /*BindToTemporary=*/false, Context))
4466  B = R;
4467  }
4468  }
4469  return B;
4470  }
4471 
4472  case Stmt::CXXDefaultArgExprClass:
4473  E = cast<CXXDefaultArgExpr>(E)->getExpr();
4474  goto tryAgain;
4475 
4476  case Stmt::CXXDefaultInitExprClass:
4477  E = cast<CXXDefaultInitExpr>(E)->getExpr();
4478  goto tryAgain;
4479  }
4480 }
4481 
4482 CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E,
4483  TempDtorContext &Context) {
4484  if (isa<LambdaExpr>(E)) {
4485  // Do not visit the children of lambdas; they have their own CFGs.
4486  return Block;
4487  }
4488 
4489  // When visiting children for destructors we want to visit them in reverse
4490  // order that they will appear in the CFG. Because the CFG is built
4491  // bottom-up, this means we visit them in their natural order, which
4492  // reverses them in the CFG.
4493  CFGBlock *B = Block;
4494  for (Stmt *Child : E->children())
4495  if (Child)
4496  if (CFGBlock *R = VisitForTemporaryDtors(Child, false, Context))
4497  B = R;
4498 
4499  return B;
4500 }
4501 
4502 CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(
4503  BinaryOperator *E, TempDtorContext &Context) {
4504  if (E->isLogicalOp()) {
4505  VisitForTemporaryDtors(E->getLHS(), false, Context);
4506  TryResult RHSExecuted = tryEvaluateBool(E->getLHS());
4507  if (RHSExecuted.isKnown() && E->getOpcode() == BO_LOr)
4508  RHSExecuted.negate();
4509 
4510  // We do not know at CFG-construction time whether the right-hand-side was
4511  // executed, thus we add a branch node that depends on the temporary
4512  // constructor call.
4513  TempDtorContext RHSContext(
4514  bothKnownTrue(Context.KnownExecuted, RHSExecuted));
4515  VisitForTemporaryDtors(E->getRHS(), false, RHSContext);
4516  InsertTempDtorDecisionBlock(RHSContext);
4517 
4518  return Block;
4519  }
4520 
4521  if (E->isAssignmentOp()) {
4522  // For assignment operator (=) LHS expression is visited
4523  // before RHS expression. For destructors visit them in reverse order.
4524  CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
4525  CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
4526  return LHSBlock ? LHSBlock : RHSBlock;
4527  }
4528 
4529  // For any other binary operator RHS expression is visited before
4530  // LHS expression (order of children). For destructors visit them in reverse
4531  // order.
4532  CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
4533  CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
4534  return RHSBlock ? RHSBlock : LHSBlock;
4535 }
4536 
4537 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors(
4538  CXXBindTemporaryExpr *E, bool BindToTemporary, TempDtorContext &Context) {
4539  // First add destructors for temporaries in subexpression.
4540  CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr(), false, Context);
4541  if (!BindToTemporary) {
4542  // If lifetime of temporary is not prolonged (by assigning to constant
4543  // reference) add destructor for it.
4544 
4545  const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor();
4546 
4547  if (Dtor->getParent()->isAnyDestructorNoReturn()) {
4548  // If the destructor is marked as a no-return destructor, we need to
4549  // create a new block for the destructor which does not have as a
4550  // successor anything built thus far. Control won't flow out of this
4551  // block.
4552  if (B) Succ = B;
4553  Block = createNoReturnBlock();
4554  } else if (Context.needsTempDtorBranch()) {
4555  // If we need to introduce a branch, we add a new block that we will hook
4556  // up to a decision block later.
4557  if (B) Succ = B;
4558  Block = createBlock();
4559  } else {
4560  autoCreateBlock();
4561  }
4562  if (Context.needsTempDtorBranch()) {
4563  Context.setDecisionPoint(Succ, E);
4564  }
4565  appendTemporaryDtor(Block, E);
4566 
4567  B = Block;
4568  }
4569  return B;
4570 }
4571 
4572 void CFGBuilder::InsertTempDtorDecisionBlock(const TempDtorContext &Context,
4573  CFGBlock *FalseSucc) {
4574  if (!Context.TerminatorExpr) {
4575  // If no temporary was found, we do not need to insert a decision point.
4576  return;
4577  }
4578  assert(Context.TerminatorExpr);
4579  CFGBlock *Decision = createBlock(false);
4580  Decision->setTerminator(CFGTerminator(Context.TerminatorExpr, true));
4581  addSuccessor(Decision, Block, !Context.KnownExecuted.isFalse());
4582  addSuccessor(Decision, FalseSucc ? FalseSucc : Context.Succ,
4583  !Context.KnownExecuted.isTrue());
4584  Block = Decision;
4585 }
4586 
4587 CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors(
4588  AbstractConditionalOperator *E, bool BindToTemporary,
4589  TempDtorContext &Context) {
4590  VisitForTemporaryDtors(E->getCond(), false, Context);
4591  CFGBlock *ConditionBlock = Block;
4592  CFGBlock *ConditionSucc = Succ;
4593  TryResult ConditionVal = tryEvaluateBool(E->getCond());
4594  TryResult NegatedVal = ConditionVal;
4595  if (NegatedVal.isKnown()) NegatedVal.negate();
4596 
4597  TempDtorContext TrueContext(
4598  bothKnownTrue(Context.KnownExecuted, ConditionVal));
4599  VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary, TrueContext);
4600  CFGBlock *TrueBlock = Block;
4601 
4602  Block = ConditionBlock;
4603  Succ = ConditionSucc;
4604  TempDtorContext FalseContext(
4605  bothKnownTrue(Context.KnownExecuted, NegatedVal));
4606  VisitForTemporaryDtors(E->getFalseExpr(), BindToTemporary, FalseContext);
4607 
4608  if (TrueContext.TerminatorExpr && FalseContext.TerminatorExpr) {
4609  InsertTempDtorDecisionBlock(FalseContext, TrueBlock);
4610  } else if (TrueContext.TerminatorExpr) {
4611  Block = TrueBlock;
4612  InsertTempDtorDecisionBlock(TrueContext);
4613  } else {
4614  InsertTempDtorDecisionBlock(FalseContext);
4615  }
4616  return Block;
4617 }
4618 
4619 /// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has
4620 /// no successors or predecessors. If this is the first block created in the
4621 /// CFG, it is automatically set to be the Entry and Exit of the CFG.
4623  bool first_block = begin() == end();
4624 
4625  // Create the block.
4626  CFGBlock *Mem = getAllocator().Allocate<CFGBlock>();
4627  new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this);
4628  Blocks.push_back(Mem, BlkBVC);
4629 
4630  // If this is the first block, set it as the Entry and Exit.
4631  if (first_block)
4632  Entry = Exit = &back();
4633 
4634  // Return the block.
4635  return &back();
4636 }
4637 
4638 /// buildCFG - Constructs a CFG from an AST.
4639 std::unique_ptr<CFG> CFG::buildCFG(const Decl *D, Stmt *Statement,
4640  ASTContext *C, const BuildOptions &BO) {
4641  CFGBuilder Builder(C, BO);
4642  return Builder.buildCFG(D, Statement);
4643 }
4644 
4645 const CXXDestructorDecl *
4647  switch (getKind()) {
4650  case CFGElement::LoopExit:
4652  case CFGElement::Statement:
4656  case CFGElement::ScopeEnd:
4657  llvm_unreachable("getDestructorDecl should only be used with "
4658  "ImplicitDtors");
4660  const VarDecl *var = castAs<CFGAutomaticObjDtor>().getVarDecl();
4661  QualType ty = var->getType();
4662 
4663  // FIXME: See CFGBuilder::addLocalScopeForVarDecl.
4664  //
4665  // Lifetime-extending constructs are handled here. This works for a single
4666  // temporary in an initializer expression.
4667  if (ty->isReferenceType()) {
4668  if (const Expr *Init = var->getInit()) {
4669  ty = getReferenceInitTemporaryType(Init);
4670  }
4671  }
4672 
4673  while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) {
4674  ty = arrayType->getElementType();
4675  }
4676  const RecordType *recordType = ty->getAs<RecordType>();
4677  const CXXRecordDecl *classDecl =
4678  cast<CXXRecordDecl>(recordType->getDecl());
4679  return classDecl->getDestructor();
4680  }
4681  case CFGElement::DeleteDtor: {
4682  const CXXDeleteExpr *DE = castAs<CFGDeleteDtor>().getDeleteExpr();
4683  QualType DTy = DE->getDestroyedType();
4684  DTy = DTy.getNonReferenceType();
4685  const CXXRecordDecl *classDecl =
4686  astContext.getBaseElementType(DTy)->getAsCXXRecordDecl();
4687  return classDecl->getDestructor();
4688  }
4690  const CXXBindTemporaryExpr *bindExpr =
4691  castAs<CFGTemporaryDtor>().getBindTemporaryExpr();
4692  const CXXTemporary *temp = bindExpr->getTemporary();
4693  return temp->getDestructor();
4694  }
4695  case CFGElement::BaseDtor:
4697  // Not yet supported.
4698  return nullptr;
4699  }
4700  llvm_unreachable("getKind() returned bogus value");
4701 }
4702 
4703 bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const {
4704  if (const CXXDestructorDecl *DD = getDestructorDecl(astContext))
4705  return DD->isNoReturn();
4706  return false;
4707 }
4708 
4709 //===----------------------------------------------------------------------===//
4710 // CFGBlock operations.
4711 //===----------------------------------------------------------------------===//
4712 
4714  : ReachableBlock(IsReachable ? B : nullptr),
4715  UnreachableBlock(!IsReachable ? B : nullptr,
4716  B && IsReachable ? AB_Normal : AB_Unreachable) {}
4717 
4719  : ReachableBlock(B),
4720  UnreachableBlock(B == AlternateBlock ? nullptr : AlternateBlock,
4721  B == AlternateBlock ? AB_Alternate : AB_Normal) {}
4722 
4724  BumpVectorContext &C) {
4725  if (CFGBlock *B = Succ.getReachableBlock())
4726  B->Preds.push_back(AdjacentBlock(this, Succ.isReachable()), C);
4727 
4728  if (CFGBlock *UnreachableB = Succ.getPossiblyUnreachableBlock())
4729  UnreachableB->Preds.push_back(AdjacentBlock(this, false), C);
4730 
4731  Succs.push_back(Succ, C);
4732 }
4733 
4735  const CFGBlock *From, const CFGBlock *To) {
4736  if (F.IgnoreNullPredecessors && !From)
4737  return true;
4738 
4739  if (To && From && F.IgnoreDefaultsWithCoveredEnums) {
4740  // If the 'To' has no label or is labeled but the label isn't a
4741  // CaseStmt then filter this edge.
4742  if (const SwitchStmt *S =
4743  dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) {
4744  if (S->isAllEnumCasesCovered()) {
4745  const Stmt *L = To->getLabel();
4746  if (!L || !isa<CaseStmt>(L))
4747  return true;
4748  }
4749  }
4750  }
4751 
4752  return false;
4753 }
4754 
4755 //===----------------------------------------------------------------------===//
4756 // CFG pretty printing
4757 //===----------------------------------------------------------------------===//
4758 
4759 namespace {
4760 
4761 class StmtPrinterHelper : public PrinterHelper {
4762  using StmtMapTy = llvm::DenseMap<const Stmt *, std::pair<unsigned, unsigned>>;
4763  using DeclMapTy = llvm::DenseMap<const Decl *, std::pair<unsigned, unsigned>>;
4764 
4765  StmtMapTy StmtMap;
4766  DeclMapTy DeclMap;
4767  signed currentBlock = 0;
4768  unsigned currStmt = 0;
4769  const LangOptions &LangOpts;
4770 
4771 public:
4772  StmtPrinterHelper(const CFG* cfg, const LangOptions &LO)
4773  : LangOpts(LO) {
4774  for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) {
4775  unsigned j = 1;
4776  for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ;
4777  BI != BEnd; ++BI, ++j ) {
4778  if (Optional<CFGStmt> SE = BI->getAs<CFGStmt>()) {
4779  const Stmt *stmt= SE->getStmt();
4780  std::pair<unsigned, unsigned> P((*I)->getBlockID(), j);
4781  StmtMap[stmt] = P;
4782 
4783  switch (stmt->getStmtClass()) {
4784  case Stmt::DeclStmtClass:
4785  DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P;
4786  break;
4787  case Stmt::IfStmtClass: {
4788  const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable();
4789  if (var)
4790  DeclMap[var] = P;
4791  break;
4792  }
4793  case Stmt::ForStmtClass: {
4794  const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable();
4795  if (var)
4796  DeclMap[var] = P;
4797  break;
4798  }
4799  case Stmt::WhileStmtClass: {
4800  const VarDecl *var =
4801  cast<WhileStmt>(stmt)->getConditionVariable();
4802  if (var)
4803  DeclMap[var] = P;
4804  break;
4805  }
4806  case Stmt::SwitchStmtClass: {
4807  const VarDecl *var =
4808  cast<SwitchStmt>(stmt)->getConditionVariable();
4809  if (var)
4810  DeclMap[var] = P;
4811  break;
4812  }
4813  case Stmt::CXXCatchStmtClass: {
4814  const VarDecl *var =
4815  cast<CXXCatchStmt>(stmt)->getExceptionDecl();
4816  if (var)
4817  DeclMap[var] = P;
4818  break;
4819  }
4820  default:
4821  break;
4822  }
4823  }
4824  }
4825  }
4826  }
4827 
4828  ~StmtPrinterHelper() override = default;
4829 
4830  const LangOptions &getLangOpts() const { return LangOpts; }
4831  void setBlockID(signed i) { currentBlock = i; }
4832  void setStmtID(unsigned i) { currStmt = i; }
4833 
4834  bool handledStmt(Stmt *S, raw_ostream &OS) override {
4835  StmtMapTy::iterator I = StmtMap.find(S);
4836 
4837  if (I == StmtMap.end())
4838  return false;
4839 
4840  if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
4841  && I->second.second == currStmt) {
4842  return false;
4843  }
4844 
4845  OS << "[B" << I->second.first << "." << I->second.second << "]";
4846  return true;
4847  }
4848 
4849  bool handleDecl(const Decl *D, raw_ostream &OS) {
4850  DeclMapTy::iterator I = DeclMap.find(D);
4851 
4852  if (I == DeclMap.end())
4853  return false;
4854 
4855  if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
4856  && I->second.second == currStmt) {
4857  return false;
4858  }
4859 
4860  OS << "[B" << I->second.first << "." << I->second.second << "]";
4861  return true;
4862  }
4863 };
4864 
4865 class CFGBlockTerminatorPrint
4866  : public StmtVisitor<CFGBlockTerminatorPrint,void> {
4867  raw_ostream &OS;
4868  StmtPrinterHelper* Helper;
4869  PrintingPolicy Policy;
4870 
4871 public:
4872  CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper,
4873  const PrintingPolicy &Policy)
4874  : OS(os), Helper(helper), Policy(Policy) {
4875  this->Policy.IncludeNewlines = false;
4876  }
4877 
4878  void VisitIfStmt(IfStmt *I) {
4879  OS << "if ";
4880  if (Stmt *C = I->getCond())
4881  C->printPretty(OS, Helper, Policy);
4882  }
4883 
4884  // Default case.
4885  void VisitStmt(Stmt *Terminator) {
4886  Terminator->printPretty(OS, Helper, Policy);
4887  }
4888 
4889  void VisitDeclStmt(DeclStmt *DS) {
4890  VarDecl *VD = cast<VarDecl>(DS->getSingleDecl());
4891  OS << "static init " << VD->getName();
4892  }
4893 
4894  void VisitForStmt(ForStmt *F) {
4895  OS << "for (" ;
4896  if (F->getInit())
4897  OS << "...";
4898  OS << "; ";
4899  if (Stmt *C = F->getCond())
4900  C->printPretty(OS, Helper, Policy);
4901  OS << "; ";
4902  if (F->getInc())
4903  OS << "...";
4904  OS << ")";
4905  }
4906 
4907  void VisitWhileStmt(WhileStmt *W) {
4908  OS << "while " ;
4909  if (Stmt *C = W->getCond())
4910  C->printPretty(OS, Helper, Policy);
4911  }
4912 
4913  void VisitDoStmt(DoStmt *D) {
4914  OS << "do ... while ";
4915  if (Stmt *C = D->getCond())
4916  C->printPretty(OS, Helper, Policy);
4917  }
4918 
4919  void VisitSwitchStmt(SwitchStmt *Terminator) {
4920  OS << "switch ";
4921  Terminator->getCond()->printPretty(OS, Helper, Policy);
4922  }
4923 
4924  void VisitCXXTryStmt(CXXTryStmt *CS) {
4925  OS << "try ...";
4926  }
4927 
4928  void VisitSEHTryStmt(SEHTryStmt *CS) {
4929  OS << "__try ...";
4930  }
4931 
4932  void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) {
4933  if (Stmt *Cond = C->getCond())
4934  Cond->printPretty(OS, Helper, Policy);
4935  OS << " ? ... : ...";
4936  }
4937 
4938  void VisitChooseExpr(ChooseExpr *C) {
4939  OS << "__builtin_choose_expr( ";
4940  if (Stmt *Cond = C->getCond())
4941  Cond->printPretty(OS, Helper, Policy);
4942  OS << " )";
4943  }
4944 
4945  void VisitIndirectGotoStmt(IndirectGotoStmt *I) {
4946  OS << "goto *";
4947  if (Stmt *T = I->getTarget())
4948  T->printPretty(OS, Helper, Policy);
4949  }
4950 
4951  void VisitBinaryOperator(BinaryOperator* B) {
4952  if (!B->isLogicalOp()) {
4953  VisitExpr(B);
4954  return;
4955  }
4956 
4957  if (B->getLHS())
4958  B->getLHS()->printPretty(OS, Helper, Policy);
4959 
4960  switch (B->getOpcode()) {
4961  case BO_LOr:
4962  OS << " || ...";
4963  return;
4964  case BO_LAnd:
4965  OS << " && ...";
4966  return;
4967  default:
4968  llvm_unreachable("Invalid logical operator.");
4969  }
4970  }
4971 
4972  void VisitExpr(Expr *E) {
4973  E->printPretty(OS, Helper, Policy);
4974  }
4975 
4976 public:
4977  void print(CFGTerminator T) {
4978  if (T.isTemporaryDtorsBranch())
4979  OS << "(Temp Dtor) ";
4980  Visit(T.getStmt());
4981  }
4982 };
4983 
4984 } // namespace
4985 
4986 static void print_initializer(raw_ostream &OS, StmtPrinterHelper &Helper,
4987  const CXXCtorInitializer *I) {
4988  if (I->isBaseInitializer())
4989  OS << I->getBaseClass()->getAsCXXRecordDecl()->getName();
4990  else if (I->isDelegatingInitializer())
4992  else
4993  OS << I->getAnyMember()->getName();
4994  OS << "(";
4995  if (Expr *IE = I->getInit())
4996  IE->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
4997  OS << ")";
4998 
4999  if (I->isBaseInitializer())
5000  OS << " (Base initializer)";
5001  else if (I->isDelegatingInitializer())
5002  OS << " (Delegating initializer)";
5003  else
5004  OS << " (Member initializer)";
5005 }
5006 
5007 static void print_construction_context(raw_ostream &OS,
5008  StmtPrinterHelper &Helper,
5009  const ConstructionContext *CC) {
5011  switch (CC->getKind()) {
5013  OS << ", ";
5014  const auto *SICC = cast<SimpleConstructorInitializerConstructionContext>(CC);
5015  print_initializer(OS, Helper, SICC->getCXXCtorInitializer());
5016  return;
5017  }
5019  OS << ", ";
5020  const auto *CICC =
5021  cast<CXX17ElidedCopyConstructorInitializerConstructionContext>(CC);
5022  print_initializer(OS, Helper, CICC->getCXXCtorInitializer());
5023  Stmts.push_back(CICC->getCXXBindTemporaryExpr());
5024  break;
5025  }
5027  const auto *SDSCC = cast<SimpleVariableConstructionContext>(CC);
5028  Stmts.push_back(SDSCC->getDeclStmt());
5029  break;
5030  }
5032  const auto *CDSCC = cast<CXX17ElidedCopyVariableConstructionContext>(CC);
5033  Stmts.push_back(CDSCC->getDeclStmt());
5034  Stmts.push_back(CDSCC->getCXXBindTemporaryExpr());
5035  break;
5036  }
5038  const auto *NECC = cast<NewAllocatedObjectConstructionContext>(CC);
5039  Stmts.push_back(NECC->getCXXNewExpr());
5040  break;
5041  }
5043  const auto *RSCC = cast<SimpleReturnedValueConstructionContext>(CC);
5044  Stmts.push_back(RSCC->getReturnStmt());
5045  break;
5046  }
5048  const auto *RSCC =
5049  cast<CXX17ElidedCopyReturnedValueConstructionContext>(CC);
5050  Stmts.push_back(RSCC->getReturnStmt());
5051  Stmts.push_back(RSCC->getCXXBindTemporaryExpr());
5052  break;
5053  }
5055  const auto *TOCC = cast<SimpleTemporaryObjectConstructionContext>(CC);
5056  Stmts.push_back(TOCC->getCXXBindTemporaryExpr());
5057  Stmts.push_back(TOCC->getMaterializedTemporaryExpr());
5058  break;
5059  }
5061  const auto *TOCC = cast<ElidedTemporaryObjectConstructionContext>(CC);
5062  Stmts.push_back(TOCC->getCXXBindTemporaryExpr());
5063  Stmts.push_back(TOCC->getMaterializedTemporaryExpr());
5064  Stmts.push_back(TOCC->getConstructorAfterElision());
5065  break;
5066  }
5068  const auto *ACC = cast<ArgumentConstructionContext>(CC);
5069  if (const Stmt *BTE = ACC->getCXXBindTemporaryExpr()) {
5070  OS << ", ";
5071  Helper.handledStmt(const_cast<Stmt *>(BTE), OS);
5072  }
5073  OS << ", ";
5074  Helper.handledStmt(const_cast<Expr *>(ACC->getCallLikeExpr()), OS);
5075  OS << "+" << ACC->getIndex();
5076  return;
5077  }
5078  }
5079  for (auto I: Stmts)
5080  if (I) {
5081  OS << ", ";
5082  Helper.handledStmt(const_cast<Stmt *>(I), OS);
5083  }
5084 }
5085 
5086 static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
5087  const CFGElement &E) {
5088  if (Optional<CFGStmt> CS = E.getAs<CFGStmt>()) {
5089  const Stmt *S = CS->getStmt();
5090  assert(S != nullptr && "Expecting non-null Stmt");
5091 
5092  // special printing for statement-expressions.
5093  if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) {
5094  const CompoundStmt *Sub = SE->getSubStmt();
5095 
5096  auto Children = Sub->children();
5097  if (Children.begin() != Children.end()) {
5098  OS << "({ ... ; ";
5099  Helper.handledStmt(*SE->getSubStmt()->body_rbegin(),OS);
5100  OS << " })\n";
5101  return;
5102  }
5103  }
5104  // special printing for comma expressions.
5105  if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) {
5106  if (B->getOpcode() == BO_Comma) {
5107  OS << "... , ";
5108  Helper.handledStmt(B->getRHS(),OS);
5109  OS << '\n';
5110  return;
5111  }
5112  }
5113  S->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
5114 
5115  if (auto VTC = E.getAs<CFGCXXRecordTypedCall>()) {
5116  if (isa<CXXOperatorCallExpr>(S))
5117  OS << " (OperatorCall)";
5118  OS << " (CXXRecordTypedCall";
5119  print_construction_context(OS, Helper, VTC->getConstructionContext());
5120  OS << ")";
5121  } else if (isa<CXXOperatorCallExpr>(S)) {
5122  OS << " (OperatorCall)";
5123  } else if (isa<CXXBindTemporaryExpr>(S)) {
5124  OS << " (BindTemporary)";
5125  } else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) {
5126  OS << " (CXXConstructExpr";
5128  print_construction_context(OS, Helper, CE->getConstructionContext());
5129  }
5130  OS << ", " << CCE->getType().getAsString() << ")";
5131  } else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) {
5132  OS << " (" << CE->getStmtClassName() << ", "
5133  << CE->getCastKindName()
5134  << ", " << CE->getType().getAsString()
5135  << ")";
5136  }
5137 
5138  // Expressions need a newline.
5139  if (isa<Expr>(S))
5140  OS << '\n';
5141  } else if (Optional<CFGInitializer> IE = E.getAs<CFGInitializer>()) {
5142  print_initializer(OS, Helper, IE->getInitializer());
5143  OS << '\n';
5144  } else if (Optional<CFGAutomaticObjDtor> DE =
5145  E.getAs<CFGAutomaticObjDtor>()) {
5146  const VarDecl *VD = DE->getVarDecl();
5147  Helper.handleDecl(VD, OS);
5148 
5149  ASTContext &ACtx = VD->getASTContext();
5150  QualType T = VD->getType();
5151  if (T->isReferenceType())
5152  T = getReferenceInitTemporaryType(VD->getInit(), nullptr);
5153  if (const ArrayType *AT = ACtx.getAsArrayType(T))
5154  T = ACtx.getBaseElementType(AT);
5155 
5156  OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()";
5157  OS << " (Implicit destructor)\n";
5158  } else if (Optional<CFGLifetimeEnds> DE = E.getAs<CFGLifetimeEnds>()) {
5159  const VarDecl *VD = DE->getVarDecl();
5160  Helper.handleDecl(VD, OS);
5161 
5162  OS << " (Lifetime ends)\n";
5163  } else if (Optional<CFGLoopExit> LE = E.getAs<CFGLoopExit>()) {
5164  const Stmt *LoopStmt = LE->getLoopStmt();
5165  OS << LoopStmt->getStmtClassName() << " (LoopExit)\n";
5166  } else if (Optional<CFGScopeBegin> SB = E.getAs<CFGScopeBegin>()) {
5167  OS << "CFGScopeBegin(";
5168  if (const VarDecl *VD = SB->getVarDecl())
5169  OS << VD->getQualifiedNameAsString();
5170  OS << ")\n";
5171  } else if (Optional<CFGScopeEnd> SE = E.getAs<CFGScopeEnd>()) {
5172  OS << "CFGScopeEnd(";
5173  if (const VarDecl *VD = SE->getVarDecl())
5174  OS << VD->getQualifiedNameAsString();
5175  OS << ")\n";
5176  } else if (Optional<CFGNewAllocator> NE = E.getAs<CFGNewAllocator>()) {
5177  OS << "CFGNewAllocator(";
5178  if (const CXXNewExpr *AllocExpr = NE->getAllocatorExpr())
5179  AllocExpr->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
5180  OS << ")\n";
5181  } else if (Optional<CFGDeleteDtor> DE = E.getAs<CFGDeleteDtor>()) {
5182  const CXXRecordDecl *RD = DE->getCXXRecordDecl();
5183  if (!RD)
5184  return;
5185  CXXDeleteExpr *DelExpr =
5186  const_cast<CXXDeleteExpr*>(DE->getDeleteExpr());
5187  Helper.handledStmt(cast<Stmt>(DelExpr->getArgument()), OS);
5188  OS << "->~" << RD->getName().str() << "()";
5189  OS << " (Implicit destructor)\n";
5190  } else if (Optional<CFGBaseDtor> BE = E.getAs<CFGBaseDtor>()) {
5191  const CXXBaseSpecifier *BS = BE->getBaseSpecifier();
5192  OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()";
5193  OS << " (Base object destructor)\n";
5194  } else if (Optional<CFGMemberDtor> ME = E.getAs<CFGMemberDtor>()) {
5195  const FieldDecl *FD = ME->getFieldDecl();
5196  const Type *T = FD->getType()->getBaseElementTypeUnsafe();
5197  OS << "this->" << FD->getName();
5198  OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()";
5199  OS << " (Member object destructor)\n";
5200  } else if (Optional<CFGTemporaryDtor> TE = E.getAs<CFGTemporaryDtor>()) {
5201  const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr();
5202  OS << "~";
5203  BT->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
5204  OS << "() (Temporary object destructor)\n";
5205  }
5206 }
5207 
5208 static void print_block(raw_ostream &OS, const CFG* cfg,
5209  const CFGBlock &B,
5210  StmtPrinterHelper &Helper, bool print_edges,
5211  bool ShowColors) {
5212  Helper.setBlockID(B.getBlockID());
5213 
5214  // Print the header.
5215  if (ShowColors)
5216  OS.changeColor(raw_ostream::YELLOW, true);
5217 
5218  OS << "\n [B" << B.getBlockID();
5219 
5220  if (&B == &cfg->getEntry())
5221  OS << " (ENTRY)]\n";
5222  else if (&B == &cfg->getExit())
5223  OS << " (EXIT)]\n";
5224  else if (&B == cfg->getIndirectGotoBlock())
5225  OS << " (INDIRECT GOTO DISPATCH)]\n";
5226  else if (B.hasNoReturnElement())
5227  OS << " (NORETURN)]\n";
5228  else
5229  OS << "]\n";
5230 
5231  if (ShowColors)
5232  OS.resetColor();
5233 
5234  // Print the label of this block.
5235  if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) {
5236  if (print_edges)
5237  OS << " ";
5238 
5239  if (LabelStmt *L = dyn_cast<LabelStmt>(Label))
5240  OS << L->getName();
5241  else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) {
5242  OS << "case ";
5243  if (C->getLHS())
5244  C->getLHS()->printPretty(OS, &Helper,
5245  PrintingPolicy(Helper.getLangOpts()));
5246  if (C->getRHS()) {
5247  OS << " ... ";
5248  C->getRHS()->printPretty(OS, &Helper,
5249  PrintingPolicy(Helper.getLangOpts()));
5250  }
5251  } else if (isa<DefaultStmt>(Label))
5252  OS << "default";
5253  else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) {
5254  OS << "catch (";
5255  if (CS->getExceptionDecl())
5256  CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper.getLangOpts()),
5257  0);
5258  else
5259  OS << "...";
5260  OS << ")";
5261  } else if (SEHExceptStmt *ES = dyn_cast<SEHExceptStmt>(Label)) {
5262  OS << "__except (";
5263  ES->getFilterExpr()->printPretty(OS, &Helper,
5264  PrintingPolicy(Helper.getLangOpts()), 0);
5265  OS << ")";
5266  } else
5267  llvm_unreachable("Invalid label statement in CFGBlock.");
5268 
5269  OS << ":\n";
5270  }
5271 
5272  // Iterate through the statements in the block and print them.
5273  unsigned j = 1;
5274 
5275  for (CFGBlock::const_iterator I = B.begin(), E = B.end() ;
5276  I != E ; ++I, ++j ) {
5277  // Print the statement # in the basic block and the statement itself.
5278  if (print_edges)
5279  OS << " ";
5280 
5281  OS << llvm::format("%3d", j) << ": ";
5282 
5283  Helper.setStmtID(j);
5284 
5285  print_elem(OS, Helper, *I);
5286  }
5287 
5288  // Print the terminator of this block.
5289  if (B.getTerminator()) {
5290  if (ShowColors)
5291  OS.changeColor(raw_ostream::GREEN);
5292 
5293  OS << " T: ";
5294 
5295  Helper.setBlockID(-1);
5296 
5297  PrintingPolicy PP(Helper.getLangOpts());
5298  CFGBlockTerminatorPrint TPrinter(OS, &Helper, PP);
5299  TPrinter.print(B.getTerminator());
5300  OS << '\n';
5301 
5302  if (ShowColors)
5303  OS.resetColor();
5304  }
5305 
5306  if (print_edges) {
5307  // Print the predecessors of this block.
5308  if (!B.pred_empty()) {
5309  const raw_ostream::Colors Color = raw_ostream::BLUE;
5310  if (ShowColors)
5311  OS.changeColor(Color);
5312  OS << " Preds " ;
5313  if (ShowColors)
5314  OS.resetColor();
5315  OS << '(' << B.pred_size() << "):";
5316  unsigned i = 0;
5317 
5318  if (ShowColors)
5319  OS.changeColor(Color);
5320 
5321  for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end();
5322  I != E; ++I, ++i) {
5323  if (i % 10 == 8)
5324  OS << "\n ";
5325 
5326  CFGBlock *B = *I;
5327  bool Reachable = true;
5328  if (!B) {
5329  Reachable = false;
5330  B = I->getPossiblyUnreachableBlock();
5331  }
5332 
5333  OS << " B" << B->getBlockID();
5334  if (!Reachable)
5335  OS << "(Unreachable)";
5336  }
5337 
5338  if (ShowColors)
5339  OS.resetColor();
5340 
5341  OS << '\n';
5342  }
5343 
5344  // Print the successors of this block.
5345  if (!B.succ_empty()) {
5346  const raw_ostream::Colors Color = raw_ostream::MAGENTA;
5347  if (ShowColors)
5348  OS.changeColor(Color);
5349  OS << " Succs ";
5350  if (ShowColors)
5351  OS.resetColor();
5352  OS << '(' << B.succ_size() << "):";
5353  unsigned i = 0;
5354 
5355  if (ShowColors)
5356  OS.changeColor(Color);
5357 
5358  for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end();
5359  I != E; ++I, ++i) {
5360  if (i % 10 == 8)
5361  OS << "\n ";
5362 
5363  CFGBlock *B = *I;
5364 
5365  bool Reachable = true;
5366  if (!B) {
5367  Reachable = false;
5368  B = I->getPossiblyUnreachableBlock();
5369  }
5370 
5371  if (B) {
5372  OS << " B" << B->getBlockID();
5373  if (!Reachable)
5374  OS << "(Unreachable)";
5375  }
5376  else {
5377  OS << " NULL";
5378  }
5379  }
5380 
5381  if (ShowColors)
5382  OS.resetColor();
5383  OS << '\n';
5384  }
5385  }
5386 }
5387 
5388 /// dump - A simple pretty printer of a CFG that outputs to stderr.
5389 void CFG::dump(const LangOptions &LO, bool ShowColors) const {
5390  print(llvm::errs(), LO, ShowColors);
5391 }
5392 
5393 /// print - A simple pretty printer of a CFG that outputs to an ostream.
5394 void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const {
5395  StmtPrinterHelper Helper(this, LO);
5396 
5397  // Print the entry block.
5398  print_block(OS, this, getEntry(), Helper, true, ShowColors);
5399 
5400  // Iterate through the CFGBlocks and print them one by one.
5401  for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) {
5402  // Skip the entry block, because we already printed it.
5403  if (&(**I) == &getEntry() || &(**I) == &getExit())
5404  continue;
5405 
5406  print_block(OS, this, **I, Helper, true, ShowColors);
5407  }
5408 
5409  // Print the exit block.
5410  print_block(OS, this, getExit(), Helper, true, ShowColors);
5411  OS << '\n';
5412  OS.flush();
5413 }
5414 
5415 /// dump - A simply pretty printer of a CFGBlock that outputs to stderr.
5416 void CFGBlock::dump(const CFG* cfg, const LangOptions &LO,
5417  bool ShowColors) const {
5418  print(llvm::errs(), cfg, LO, ShowColors);
5419 }
5420 
5421 LLVM_DUMP_METHOD void CFGBlock::dump() const {
5422  dump(getParent(), LangOptions(), false);
5423 }
5424 
5425 /// print - A simple pretty printer of a CFGBlock that outputs to an ostream.
5426 /// Generally this will only be called from CFG::print.
5427 void CFGBlock::print(raw_ostream &OS, const CFG* cfg,
5428  const LangOptions &LO, bool ShowColors) const {
5429  StmtPrinterHelper Helper(cfg, LO);
5430  print_block(OS, cfg, *this, Helper, true, ShowColors);
5431  OS << '\n';
5432 }
5433 
5434 /// printTerminator - A simple pretty printer of the terminator of a CFGBlock.
5435 void CFGBlock::printTerminator(raw_ostream &OS,
5436  const LangOptions &LO) const {
5437  CFGBlockTerminatorPrint TPrinter(OS, nullptr, PrintingPolicy(LO));
5438  TPrinter.print(getTerminator());
5439 }
5440 
5442  Stmt *Terminator = this->Terminator;
5443  if (!Terminator)
5444  return nullptr;
5445 
5446  Expr *E = nullptr;
5447 
5448  switch (Terminator->getStmtClass()) {
5449  default:
5450  break;
5451 
5452  case Stmt::CXXForRangeStmtClass:
5453  E = cast<CXXForRangeStmt>(Terminator)->getCond();
5454  break;
5455 
5456  case Stmt::ForStmtClass:
5457  E = cast<ForStmt>(Terminator)->getCond();
5458  break;
5459 
5460  case Stmt::WhileStmtClass:
5461  E = cast<WhileStmt>(Terminator)->getCond();
5462  break;
5463 
5464  case Stmt::DoStmtClass:
5465  E = cast<DoStmt>(Terminator)->getCond();
5466  break;
5467 
5468  case Stmt::IfStmtClass:
5469  E = cast<IfStmt>(Terminator)->getCond();
5470  break;
5471 
5472  case Stmt::ChooseExprClass:
5473  E = cast<ChooseExpr>(Terminator)->getCond();
5474  break;
5475 
5476  case Stmt::IndirectGotoStmtClass:
5477  E = cast<IndirectGotoStmt>(Terminator)->getTarget();
5478  break;
5479 
5480  case Stmt::SwitchStmtClass:
5481  E = cast<SwitchStmt>(Terminator)->getCond();
5482  break;
5483 
5484  case Stmt::BinaryConditionalOperatorClass:
5485  E = cast<BinaryConditionalOperator>(Terminator)->getCond();
5486  break;
5487 
5488  case Stmt::ConditionalOperatorClass:
5489  E = cast<ConditionalOperator>(Terminator)->getCond();
5490  break;
5491 
5492  case Stmt::BinaryOperatorClass: // '&&' and '||'
5493  E = cast<BinaryOperator>(Terminator)->getLHS();
5494  break;
5495 
5496  case Stmt::ObjCForCollectionStmtClass:
5497  return Terminator;
5498  }
5499 
5500  if (!StripParens)
5501  return E;
5502 
5503  return E ? E->IgnoreParens() : nullptr;
5504 }
5505 
5506 //===----------------------------------------------------------------------===//
5507 // CFG Graphviz Visualization
5508 //===----------------------------------------------------------------------===//
5509 
5510 #ifndef NDEBUG
5511 static StmtPrinterHelper* GraphHelper;
5512 #endif
5513 
5514 void CFG::viewCFG(const LangOptions &LO) const {
5515 #ifndef NDEBUG
5516  StmtPrinterHelper H(this, LO);
5517  GraphHelper = &H;
5518  llvm::ViewGraph(this,"CFG");
5519  GraphHelper = nullptr;
5520 #endif
5521 }
5522 
5523 namespace llvm {
5524 
5525 template<>
5526 struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits {
5527  DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
5528 
5529  static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) {
5530 #ifndef NDEBUG
5531  std::string OutSStr;
5532  llvm::raw_string_ostream Out(OutSStr);
5533  print_block(Out,Graph, *Node, *GraphHelper, false, false);
5534  std::string& OutStr = Out.str();
5535 
5536  if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
5537 
5538  // Process string output to make it nicer...
5539  for (unsigned i = 0; i != OutStr.length(); ++i)
5540  if (OutStr[i] == '\n') { // Left justify
5541  OutStr[i] = '\\';
5542  OutStr.insert(OutStr.begin()+i+1, 'l');
5543  }
5544 
5545  return OutStr;
5546 #else
5547  return {};
5548 #endif
5549  }
5550 };
5551 
5552 } // namespace llvm
Expr * getInc()
Definition: Stmt.h:1372
unsigned getNumSemanticExprs() const
Definition: Expr.h:5505
bool isBaseInitializer() const
Determine whether this initializer is initializing a base class.
Definition: DeclCXX.h:2324
bool isNoReturn() const
Determines whether this function is known to be &#39;noreturn&#39;, through an attribute on its declaration o...
Definition: Decl.cpp:2897
Defines the clang::ASTContext interface.
const BlockDecl * getBlockDecl() const
Definition: Expr.h:5317
Represents C++ allocator call.
Definition: CFG.h:240
const CXXDestructorDecl * getDestructor() const
Definition: ExprCXX.h:1308
Represents a function declaration or definition.
Definition: Decl.h:1722
Expr * getInit() const
Get the initializer.
Definition: DeclCXX.h:2453
const Stmt * getElse() const
Definition: Stmt.h:1071
CompoundStmt * getBlock() const
Definition: Stmt.h:2174
bool EvaluateAsRValue(EvalResult &Result, const ASTContext &Ctx) const
EvaluateAsRValue - Return true if this is a constant which we can fold to an rvalue using any crazy t...
A class which contains all the information about a particular captured value.
Definition: Decl.h:3843
pred_iterator pred_end()
Definition: CFG.h:734
PointerType - C99 6.7.5.1 - Pointer Declarators.
Definition: Type.h:2497
QualType getPointeeType() const
Definition: Type.h:2510
A (possibly-)qualified type.
Definition: Type.h:641
bool isBlockPointerType() const
Definition: Type.h:6220
base_class_range bases()
Definition: DeclCXX.h:831
Expr * getCond() const
Definition: Expr.h:4049
static SourceLocation GetEndLoc(Decl *D)
Definition: CFG.cpp:66
AdjacentBlocks::const_iterator const_pred_iterator
Definition: CFG.h:720
iterator beginScopeEndInsert(iterator I, size_t Cnt, BumpVectorContext &C)
Definition: CFG.h:973
const internal::VariadicAllOfMatcher< Stmt > stmt
Matches statements.
const Expr * skipRValueSubobjectAdjustments(SmallVectorImpl< const Expr *> &CommaLHS, SmallVectorImpl< SubobjectAdjustment > &Adjustments) const
Walk outwards from an expression we want to bind a reference to and find the expression whose lifetim...
Definition: Expr.cpp:77
void print(raw_ostream &OS, const PrintingPolicy &Policy, const Twine &PlaceHolder=Twine(), unsigned Indentation=0) const
Definition: Type.h:984
bool operator==(CanQual< T > x, CanQual< U > y)
Expr * getCond()
Definition: Stmt.h:1246
DOTGraphTraits(bool isSimple=false)
Definition: CFG.cpp:5527
ElementList::iterator iterator
Definition: CFG.h:695
succ_iterator succ_begin()
Definition: CFG.h:751
CompoundStmt * getSubStmt()
Definition: Expr.h:3820
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:1367
Stmt - This represents one statement.
Definition: Stmt.h:66
FunctionType - C99 6.7.5.3 - Function Declarators.
Definition: Type.h:3315
CXXCatchStmt * getHandler(unsigned i)
Definition: StmtCXX.h:120
CFGBlock & getEntry()
Definition: CFG.h:1093
IfStmt - This represents an if/then/else.
Definition: Stmt.h:1031
StorageClass getStorageClass() const
Returns the storage class as written in the source.
Definition: Decl.h:1025
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:2686
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:86
Stmt * getHandlerBlock() const
Definition: StmtCXX.h:60
Opcode getOpcode() const
Definition: Expr.h:3304
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:6161
void appendLifetimeEnds(VarDecl *VD, Stmt *S, BumpVectorContext &C)
Definition: CFG.h:932
The base class of the type hierarchy.
Definition: Type.h:1414
Represents Objective-C&#39;s @throw statement.
Definition: StmtObjC.h:353
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:2772
iterator begin()
Definition: CFG.h:703
Represents a call to a C++ constructor.
Definition: ExprCXX.h:1382
unsigned IgnoreDefaultsWithCoveredEnums
Definition: CFG.h:779
Represents a C++ constructor within a class.
Definition: DeclCXX.h:2483
Represents a prvalue temporary that is written into memory so that a reference can bind to it...
Definition: ExprCXX.h:4393
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:3148
VarDecl * getConditionVariable() const
Retrieve the variable declared in this "while" statement, if any.
Definition: Stmt.cpp:903
unsigned succ_size() const
Definition: CFG.h:769
const CXXDestructorDecl * getDestructorDecl(ASTContext &astContext) const
Definition: CFG.cpp:4646
Stmt * getSubStmt()
Definition: Stmt.h:882
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:1888
bool EvaluateAsInt(llvm::APSInt &Result, const ASTContext &Ctx, SideEffectsKind AllowSideEffects=SE_NoSideEffects) const
EvaluateAsInt - Return true if this is a constant which we can fold and convert to an integer...
Represents a variable declaration or definition.
Definition: Decl.h:820
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6625
CFGBlock * getReachableBlock() const
Get the reachable block, if one exists.
Definition: CFG.h:640
const char * getName() const
Definition: Stmt.cpp:335
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:5086
A C++ throw-expression (C++ [except.throw]).
Definition: ExprCXX.h:1094
Represents an expression – generally a full-expression – that introduces cleanups to be run at the ...
Definition: ExprCXX.h:3269
static bool isAssignmentOp(Opcode Opc)
Definition: Expr.h:3394
Defines the clang::Expr interface and subclasses for C++ expressions.
VarDecl * getConditionVariable() const
Retrieve the variable declared in this "switch" statement, if any.
Definition: Stmt.cpp:869
const Stmt * getSubStmt() const
Definition: StmtObjC.h:404
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:920
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:1302
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:2614
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:153
void setLoopTarget(const Stmt *loopTarget)
Definition: CFG.h:837
static std::string getNodeLabel(const CFGBlock *Node, const CFG *Graph)
Definition: CFG.cpp:5529
field_range fields() const
Definition: Decl.h:3763
Represents a member of a struct/union/class.
Definition: Decl.h:2554
TypeSourceInfo * getTypeSourceInfo() const
Returns the declarator information for a base class or delegating initializer.
Definition: DeclCXX.h:2385
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:5435
Represents C++ object destructor implicitly generated for automatic object or temporary bound to cons...
Definition: CFG.h:384
const Expr * getRetValue() const
Definition: Stmt.cpp:930
void appendAutomaticObjDtor(VarDecl *VD, Stmt *S, BumpVectorContext &C)
Definition: CFG.h:928
bool isReferenceType() const
Definition: Type.h:6224
const CXXConstructExpr * getConstructExpr() const
Returns the CXXConstructExpr from this new-expression, or null.
Definition: ExprCXX.h:2194
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:1189
Expr * getSubExpr()
Definition: Expr.h:3000
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:82
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:1459
Describes an C or C++ initializer list.
Definition: Expr.h:4236
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:2148
ForStmt - This represents a &#39;for (init;cond;inc)&#39; stmt.
Definition: Stmt.h:1338
APValue Val
Val - This is the value the expression can be folded to.
Definition: Expr.h:573
LabelDecl * getDecl() const
Definition: Stmt.h:937
Forward-declares and imports various common LLVM datatypes that clang wants to use unqualified...
capture_init_iterator capture_init_begin()
Retrieve the first initialization argument for this lambda expression (which initializes the first ca...
Definition: ExprCXX.h:1908
Expr * getInitializer()
The initializer of this new-expression.
Definition: ExprCXX.h:2186
Stmt * getBody()
Definition: Stmt.h:1373
CFGCallback * Observer
Definition: CFG.h:1016
child_range children()
Definition: Stmt.cpp:229
static QualType getReferenceInitTemporaryType(const Expr *Init, bool *FoundMTE=nullptr)
Retrieve the type of the temporary object whose lifetime was extended by a local reference with the g...
Definition: CFG.cpp:1553
A builtin binary operation expression such as "x + y" or "x <= y".
Definition: Expr.h:3263
Stmt * getInit()
Definition: Stmt.h:1352
CXXForRangeStmt - This represents C++0x [stmt.ranged]&#39;s ranged for statement, represented as &#39;for (ra...
Definition: StmtCXX.h:142
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:5427
void printPretty(raw_ostream &OS, PrinterHelper *Helper, const PrintingPolicy &Policy, unsigned Indentation=0, const ASTContext *Context=nullptr) const
Scope - A scope is a transient data structure that is used while parsing the program.
Definition: Scope.h:40
const Type * getTypePtr() const
Retrieves a pointer to the underlying (unqualified) type.
Definition: Type.h:5988
void appendLoopExit(const Stmt *LoopStmt, BumpVectorContext &C)
Definition: CFG.h:936
Expr * getCond()
Definition: Stmt.h:1371
bool isInt() const
Definition: APValue.h:234
CastExpr - Base class for type casts, including both implicit casts (ImplicitCastExpr) and explicit c...
Definition: Expr.h:2935
Represents binding an expression to a temporary.
Definition: ExprCXX.h:1329
CXXTemporary * getTemporary()
Definition: ExprCXX.h:1348
FieldDecl * getAnyMember() const
Definition: DeclCXX.h:2397
A C++ lambda expression, which produces a function object (of unspecified type) that can be invoked l...
Definition: ExprCXX.h:1763
bool hasTrivialDestructor() const
Determine whether this class has a trivial destructor (C++ [class.dtor]p3)
Definition: DeclCXX.h:1488
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:743
CXXDestructorDecl * getDestructor() const
Returns the destructor decl for this class.
Definition: DeclCXX.cpp:1674
VarDecl * getConditionVariable() const
Retrieve the variable declared in this "for" statement, if any.
Definition: Stmt.cpp:841
bool getNoReturn() const
Definition: Type.h:3386
Stmt * getInit()
Definition: Stmt.h:1064
arg_iterator placement_arg_end()
Definition: ExprCXX.h:2225
Iterator for iterating over Stmt * arrays that contain only Expr *.
Definition: Stmt.h:345
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:637
CXXRecordDecl * getAsCXXRecordDecl() const
Retrieves the CXXRecordDecl that this type refers to, either because the type is a RecordType or beca...
Definition: Type.cpp:1627
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3536
bool isDelegatingInitializer() const
Determine whether this initializer is creating a delegating constructor.
Definition: DeclCXX.h:2352
UnaryExprOrTypeTraitExpr - expression with either a type or (unevaluated) expression operand...
Definition: Expr.h:2212
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:3909
Represents a single basic block in a source-level CFG.
Definition: CFG.h:552
const DeclStmt * getConditionVariableDeclStmt() const
If this IfStmt has a condition variable, return the faux DeclStmt associated with the creation of tha...
Definition: Stmt.h:1060
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:4703
Expr - This represents one expression.
Definition: Expr.h:106
Defines the clang::LangOptions interface.
Stmt * getTerminatorCondition(bool StripParens=true)
Definition: CFG.cpp:5441
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:172
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:1705
const Stmt * getThen() const
Definition: Stmt.h:1069
BlockExpr - Adaptor class for mixing a BlockDecl with expressions.
Definition: Expr.h:5303
Represents a C++ destructor within a class.
Definition: DeclCXX.h:2705
bool succ_empty() const
Definition: CFG.h:770
VarDecl * getExceptionDecl() const
Definition: StmtCXX.h:58
unsigned getNumInits() const
Definition: Expr.h:4266
const Expr * getCallee() const
Definition: Expr.h:2446
Represents C++ constructor call.
Definition: CFG.h:151
QualType getArgumentType() const
Definition: Expr.h:2249
#define bool
Definition: stdbool.h:31
Stmt * getBody()
Definition: Stmt.h:1249
const CompoundStmt * getSynchBody() const
Definition: StmtObjC.h:314
ElementList::const_iterator const_iterator
Definition: CFG.h:696
Expr * getRHS()
Definition: Stmt.h:825
bool isTemporaryDtorsBranch() const
Definition: CFG.h:513
Represents Objective-C&#39;s @synchronized statement.
Definition: StmtObjC.h:294
SourceLocation Begin
CXXTryStmt - A C++ try block, including all handlers.
Definition: StmtCXX.h:73
const AstTypeMatcher< ArrayType > arrayType
Matches all kinds of arrays.
std::reverse_iterator< body_iterator > reverse_body_iterator
Definition: Stmt.h:703
QualType getType() const
Definition: Expr.h:128
static void print_initializer(raw_ostream &OS, StmtPrinterHelper &Helper, const CXXCtorInitializer *I)
Definition: CFG.cpp:4986
LabelDecl * getLabel() const
Definition: Stmt.h:1429
StorageDuration getStorageDuration() const
Retrieve the storage duration for the materialized temporary.
Definition: ExprCXX.h:4437
ReturnStmt - This represents a return, optionally of an expression: return; return 4;...
Definition: Stmt.h:1588
An expression that sends a message to the given Objective-C object or class.
Definition: ExprObjC.h:992
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:1865
static bool CanThrow(Expr *E, ASTContext &Ctx)
Definition: CFG.cpp:2396
const Type * getBaseElementTypeUnsafe() const
Get the base element type of this type, potentially discarding type qualifiers.
Definition: Type.h:6583
ValueDecl * getDecl()
Definition: Expr.h:1065
Represents C++ object destructor implicitly generated for base object in destructor.
Definition: CFG.h:435
The result type of a method or function.
QualType getDestroyedType() const
Retrieve the type being destroyed.
Definition: ExprCXX.cpp:178
const Expr * getSubExpr() const
Definition: ExprCXX.h:1352
bool isNull() const
Return true if this QualType doesn&#39;t point to a type yet.
Definition: Type.h:706
DoStmt - This represents a &#39;do/while&#39; stmt.
Definition: Stmt.h:1281
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:577
RecordDecl * getDecl() const
Definition: Type.h:4249
Expr * getArgument()
Definition: ExprCXX.h:2334
void appendStmt(Stmt *statement, BumpVectorContext &C)
Definition: CFG.h:873
CFGTerminator getTerminator()
Definition: CFG.h:840
OpaqueValueExpr - An expression referring to an opaque object of a fixed type and value class...
Definition: Expr.h:875
Kind
PseudoObjectExpr - An expression which accesses a pseudo-object l-value.
Definition: Expr.h:5441
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:119
Expr * getSubExpr() const
Definition: Expr.h:1892
Represents a C++ temporary.
Definition: ExprCXX.h:1297
const SwitchCase * getSwitchCaseList() const
Definition: Stmt.h:1157
Represents a new-expression for memory allocation and constructor calls, e.g: "new CXXNewExpr(foo)"...
Definition: ExprCXX.h:2041
Expr * getLHS()
Definition: Stmt.h:824
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:4639
ASTContext & getASTContext() const LLVM_READONLY
Definition: DeclBase.cpp:376
iterator insertScopeEnd(iterator I, VarDecl *VD, Stmt *S)
Definition: CFG.h:977
DeclStmt - Adaptor class for mixing declarations with statements and expressions. ...
Definition: Stmt.h:509
bool PruneTriviallyFalseEdges
Definition: CFG.h:1017
reverse_body_iterator body_rend()
Definition: Stmt.h:709
QualType getBaseElementType(const ArrayType *VAT) const
Return the innermost element type of an array type.
const ConstantArrayType * getAsConstantArrayType(QualType T) const
Definition: ASTContext.h:2417
virtual void compareAlwaysTrue(const BinaryOperator *B, bool isAlwaysTrue)
Definition: CFG.h:991
StmtVisitor - This class implements a simple visitor for Stmt subclasses.
Definition: StmtVisitor.h:186
static void print_block(raw_ostream &OS, const CFG *cfg, const CFGBlock &B, StmtPrinterHelper &Helper, bool print_edges, bool ShowColors)
Definition: CFG.cpp:5208
const ArrayType * getAsArrayType(QualType T) const
Type Query functions.
bool isArray() const
Definition: ExprCXX.h:2146
decl_iterator decl_begin()
Definition: Stmt.h:572
bool isValueDependent() const
isValueDependent - Determines whether this expression is value-dependent (C++ [temp.dep.constexpr]).
Definition: Expr.h:149
bool isKnownToHaveBooleanValue() const
isKnownToHaveBooleanValue - Return true if this is an integer expression that is known to return 0 or...
Definition: Expr.cpp:135
reverse_decl_iterator decl_rbegin()
Definition: Stmt.h:579
ImplicitCastExpr - Allows us to explicitly represent implicit type conversions, which have no direct ...
Definition: Expr.h:3069
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:2489
Expr ** getInits()
Retrieve the set of initializers.
Definition: Expr.h:4269
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:3391
static const Expr * tryTransformToIntOrEnumConstant(const Expr *E)
Helper for tryNormalizeBinaryOperator.
Definition: CFG.cpp:75
void dump() const
Definition: CFG.cpp:5421
succ_iterator succ_end()
Definition: CFG.h:752
StmtExpr - This is the GNU Statement Expression extension: ({int X=4; X;}).
Definition: Expr.h:3804
bool isArgumentType() const
Definition: Expr.h:2248
Represents end of a scope implicitly generated by the compiler after the last Stmt in a CompoundStmt&#39;...
Definition: CFG.h:336
const DeclStmt * getConditionVariableDeclStmt() const
If this WhileStmt has a condition variable, return the faux DeclStmt associated with the creation of ...
Definition: Stmt.h:1242
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:3307
Defines various enumerations that describe declaration and type specifiers.
AddrLabelExpr - The GNU address of label extension, representing &&label.
Definition: Expr.h:3752
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:3685
VarDecl * getConditionVariable() const
Retrieve the variable declared in this "if" statement, if any.
Definition: Stmt.cpp:806
Dataflow Directional Tag Classes.
child_range children()
DeclContext - This is used only as base class of specific decl types that can act as declaration cont...
Definition: DeclBase.h:1272
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:2280
ArrayRef< Capture > captures() const
Definition: Decl.h:3956
iterator beginAutomaticObjDtorsInsert(iterator I, size_t Cnt, BumpVectorContext &C)
Definition: CFG.h:947
virtual void compareBitwiseEquality(const BinaryOperator *B, bool isAlwaysTrue)
Definition: CFG.h:992
FunctionDecl * getDirectCallee()
If the callee is a FunctionDecl, return it. Otherwise return 0.
Definition: Expr.cpp:1251
const Stmt * stripLabelLikeStatements() const
Strip off all label-like statements.
Definition: Stmt.cpp:161
static const VariableArrayType * FindVA(const Type *t)
Definition: CFG.cpp:1254
void appendCXXRecordTypedCall(Expr *E, const ConstructionContext *CC, BumpVectorContext &C)
Definition: CFG.h:882
const Expr * getInit() const
Definition: Decl.h:1225
unsigned pred_size() const
Definition: CFG.h:772
StmtClass getStmtClass() const
Definition: Stmt.h:391
static StmtPrinterHelper * GraphHelper
Definition: CFG.cpp:5511
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:2171
bool isAnyDestructorNoReturn() const
Returns true if the class destructor, or any implicitly invoked destructors are marked noreturn...
Definition: DeclCXX.cpp:1687
const Type * getBaseClass() const
If this is a base class initializer, returns the type of the base class.
Definition: DeclCXX.cpp:2229
SEHExceptStmt * getExceptHandler() const
Returns 0 if not defined.
Definition: Stmt.cpp:950
const Decl * getSingleDecl() const
Definition: Stmt.h:526
FunctionType::ExtInfo getFunctionExtInfo(const Type &t)
Definition: Type.h:6113
const Expr * getSynchExpr() const
Definition: StmtObjC.h:322
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:522
Represents the point where the lifetime of an automatic object ends.
Definition: CFG.h:285
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:2631
const Stmt * getBody() const
Definition: Stmt.h:1156
llvm::APInt getValue() const
Definition: Expr.h:1320
Represents a __leave statement.
Definition: Stmt.h:2242
LabelDecl * getLabel() const
Definition: Expr.h:3782
SwitchStmt - This represents a &#39;switch&#39; stmt.
Definition: Stmt.h:1117
Pointer to a block type.
Definition: Type.h:2599
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:4239
bool body_empty() const
Definition: Stmt.h:662
Represents Objective-C&#39;s collection statement.
Definition: StmtObjC.h:24
AbstractConditionalOperator - An abstract base class for ConditionalOperator and BinaryConditionalOpe...
Definition: Expr.h:3519
Represents a C++ base or member initializer.
Definition: DeclCXX.h:2258
reverse_decl_iterator decl_rend()
Definition: Stmt.h:583
const ConstructionContextItem & getItem() const
Stmt * getInit()
Definition: Stmt.h:1152
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:5394
CanQualType BoundMemberTy
Definition: ASTContext.h:1052
decl_range decls()
Definition: Stmt.h:566
static void print_construction_context(raw_ostream &OS, StmtPrinterHelper &Helper, const ConstructionContext *CC)
Definition: CFG.cpp:5007
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:2222
DeclStmt * getRangeStmt()
Definition: StmtCXX.h:168
Expr * getRHS() const
Definition: Expr.h:4053
SEHFinallyStmt * getFinallyHandler() const
Definition: Stmt.cpp:954
GotoStmt - This represents a direct goto.
Definition: Stmt.h:1417
A use of a default initializer in a constructor or in aggregate initialization.
Definition: ExprCXX.h:1238
Expr * getTarget()
Definition: Stmt.h:1479
unsigned IgnoreNullPredecessors
Definition: CFG.h:778
bool hasNoReturnElement() const
Definition: CFG.h:854
X
Add a minimal nested name specifier fixit hint to allow lookup of a tag name from an outer enclosing ...
Definition: SemaDecl.cpp:13790
void setHasNoReturnElement()
Definition: CFG.h:838
Expr * getCond()
Definition: Stmt.h:1299
Defines the C++ Decl subclasses, other than those for templates (found in DeclTemplate.h) and friends (in DeclFriend.h).
MemberExpr - [C99 6.5.2.3] Structure and Union Members.
Definition: Expr.h:2596
void viewCFG(const LangOptions &LO) const
Definition: CFG.cpp:5514
Defines the clang::SourceLocation class and associated facilities.
ConstructionContext&#39;s subclasses describe different ways of constructing an object in C++...
Represents a C++ struct/union/class.
Definition: DeclCXX.h:308
ContinueStmt - This represents a continue.
Definition: Stmt.h:1510