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  // If this is a call to a no-return function, this stops the block here.
2425  bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn();
2426 
2427  bool AddEHEdge = false;
2428 
2429  // Languages without exceptions are assumed to not throw.
2430  if (Context->getLangOpts().Exceptions) {
2431  if (BuildOpts.AddEHEdges)
2432  AddEHEdge = true;
2433  }
2434 
2435  // If this is a call to a builtin function, it might not actually evaluate
2436  // its arguments. Don't add them to the CFG if this is the case.
2437  bool OmitArguments = false;
2438 
2439  if (FunctionDecl *FD = C->getDirectCallee()) {
2440  // TODO: Support construction contexts for variadic function arguments.
2441  // These are a bit problematic and not very useful because passing
2442  // C++ objects as C-style variadic arguments doesn't work in general
2443  // (see [expr.call]).
2444  if (!FD->isVariadic())
2445  findConstructionContextsForArguments(C);
2446 
2447  if (FD->isNoReturn() || C->isBuiltinAssumeFalse(*Context))
2448  NoReturn = true;
2449  if (FD->hasAttr<NoThrowAttr>())
2450  AddEHEdge = false;
2451  if (FD->getBuiltinID() == Builtin::BI__builtin_object_size)
2452  OmitArguments = true;
2453  }
2454 
2455  if (!CanThrow(C->getCallee(), *Context))
2456  AddEHEdge = false;
2457 
2458  if (OmitArguments) {
2459  assert(!NoReturn && "noreturn calls with unevaluated args not implemented");
2460  assert(!AddEHEdge && "EH calls with unevaluated args not implemented");
2461  autoCreateBlock();
2462  appendStmt(Block, C);
2463  return Visit(C->getCallee());
2464  }
2465 
2466  if (!NoReturn && !AddEHEdge) {
2467  autoCreateBlock();
2468  appendCall(Block, C);
2469 
2470  return VisitChildren(C);
2471  }
2472 
2473  if (Block) {
2474  Succ = Block;
2475  if (badCFG)
2476  return nullptr;
2477  }
2478 
2479  if (NoReturn)
2480  Block = createNoReturnBlock();
2481  else
2482  Block = createBlock();
2483 
2484  appendCall(Block, C);
2485 
2486  if (AddEHEdge) {
2487  // Add exceptional edges.
2488  if (TryTerminatedBlock)
2489  addSuccessor(Block, TryTerminatedBlock);
2490  else
2491  addSuccessor(Block, &cfg->getExit());
2492  }
2493 
2494  return VisitChildren(C);
2495 }
2496 
2497 CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C,
2498  AddStmtChoice asc) {
2499  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2500  appendStmt(ConfluenceBlock, C);
2501  if (badCFG)
2502  return nullptr;
2503 
2504  AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2505  Succ = ConfluenceBlock;
2506  Block = nullptr;
2507  CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd);
2508  if (badCFG)
2509  return nullptr;
2510 
2511  Succ = ConfluenceBlock;
2512  Block = nullptr;
2513  CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd);
2514  if (badCFG)
2515  return nullptr;
2516 
2517  Block = createBlock(false);
2518  // See if this is a known constant.
2519  const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2520  addSuccessor(Block, KnownVal.isFalse() ? nullptr : LHSBlock);
2521  addSuccessor(Block, KnownVal.isTrue() ? nullptr : RHSBlock);
2522  Block->setTerminator(C);
2523  return addStmt(C->getCond());
2524 }
2525 
2526 CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) {
2527  LocalScope::const_iterator scopeBeginPos = ScopePos;
2528  addLocalScopeForStmt(C);
2529 
2530  if (!C->body_empty() && !isa<ReturnStmt>(*C->body_rbegin())) {
2531  // If the body ends with a ReturnStmt, the dtors will be added in
2532  // VisitReturnStmt.
2533  addAutomaticObjHandling(ScopePos, scopeBeginPos, C);
2534  }
2535 
2536  CFGBlock *LastBlock = Block;
2537 
2539  I != E; ++I ) {
2540  // If we hit a segment of code just containing ';' (NullStmts), we can
2541  // get a null block back. In such cases, just use the LastBlock
2542  if (CFGBlock *newBlock = addStmt(*I))
2543  LastBlock = newBlock;
2544 
2545  if (badCFG)
2546  return nullptr;
2547  }
2548 
2549  return LastBlock;
2550 }
2551 
2552 CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C,
2553  AddStmtChoice asc) {
2554  const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C);
2555  const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : nullptr);
2556 
2557  // Create the confluence block that will "merge" the results of the ternary
2558  // expression.
2559  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2560  appendStmt(ConfluenceBlock, C);
2561  if (badCFG)
2562  return nullptr;
2563 
2564  AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2565 
2566  // Create a block for the LHS expression if there is an LHS expression. A
2567  // GCC extension allows LHS to be NULL, causing the condition to be the
2568  // value that is returned instead.
2569  // e.g: x ?: y is shorthand for: x ? x : y;
2570  Succ = ConfluenceBlock;
2571  Block = nullptr;
2572  CFGBlock *LHSBlock = nullptr;
2573  const Expr *trueExpr = C->getTrueExpr();
2574  if (trueExpr != opaqueValue) {
2575  LHSBlock = Visit(C->getTrueExpr(), alwaysAdd);
2576  if (badCFG)
2577  return nullptr;
2578  Block = nullptr;
2579  }
2580  else
2581  LHSBlock = ConfluenceBlock;
2582 
2583  // Create the block for the RHS expression.
2584  Succ = ConfluenceBlock;
2585  CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd);
2586  if (badCFG)
2587  return nullptr;
2588 
2589  // If the condition is a logical '&&' or '||', build a more accurate CFG.
2590  if (BinaryOperator *Cond =
2591  dyn_cast<BinaryOperator>(C->getCond()->IgnoreParens()))
2592  if (Cond->isLogicalOp())
2593  return VisitLogicalOperator(Cond, C, LHSBlock, RHSBlock).first;
2594 
2595  // Create the block that will contain the condition.
2596  Block = createBlock(false);
2597 
2598  // See if this is a known constant.
2599  const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2600  addSuccessor(Block, LHSBlock, !KnownVal.isFalse());
2601  addSuccessor(Block, RHSBlock, !KnownVal.isTrue());
2602  Block->setTerminator(C);
2603  Expr *condExpr = C->getCond();
2604 
2605  if (opaqueValue) {
2606  // Run the condition expression if it's not trivially expressed in
2607  // terms of the opaque value (or if there is no opaque value).
2608  if (condExpr != opaqueValue)
2609  addStmt(condExpr);
2610 
2611  // Before that, run the common subexpression if there was one.
2612  // At least one of this or the above will be run.
2613  return addStmt(BCO->getCommon());
2614  }
2615 
2616  return addStmt(condExpr);
2617 }
2618 
2619 CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) {
2620  // Check if the Decl is for an __label__. If so, elide it from the
2621  // CFG entirely.
2622  if (isa<LabelDecl>(*DS->decl_begin()))
2623  return Block;
2624 
2625  // This case also handles static_asserts.
2626  if (DS->isSingleDecl())
2627  return VisitDeclSubExpr(DS);
2628 
2629  CFGBlock *B = nullptr;
2630 
2631  // Build an individual DeclStmt for each decl.
2633  E = DS->decl_rend();
2634  I != E; ++I) {
2635  // Get the alignment of the new DeclStmt, padding out to >=8 bytes.
2636  unsigned A = alignof(DeclStmt) < 8 ? 8 : alignof(DeclStmt);
2637 
2638  // Allocate the DeclStmt using the BumpPtrAllocator. It will get
2639  // automatically freed with the CFG.
2640  DeclGroupRef DG(*I);
2641  Decl *D = *I;
2642  void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A);
2643  DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D));
2644  cfg->addSyntheticDeclStmt(DSNew, DS);
2645 
2646  // Append the fake DeclStmt to block.
2647  B = VisitDeclSubExpr(DSNew);
2648  }
2649 
2650  return B;
2651 }
2652 
2653 /// VisitDeclSubExpr - Utility method to add block-level expressions for
2654 /// DeclStmts and initializers in them.
2655 CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) {
2656  assert(DS->isSingleDecl() && "Can handle single declarations only.");
2657  VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl());
2658 
2659  if (!VD) {
2660  // Of everything that can be declared in a DeclStmt, only VarDecls impact
2661  // runtime semantics.
2662  return Block;
2663  }
2664 
2665  bool HasTemporaries = false;
2666 
2667  // Guard static initializers under a branch.
2668  CFGBlock *blockAfterStaticInit = nullptr;
2669 
2670  if (BuildOpts.AddStaticInitBranches && VD->isStaticLocal()) {
2671  // For static variables, we need to create a branch to track
2672  // whether or not they are initialized.
2673  if (Block) {
2674  Succ = Block;
2675  Block = nullptr;
2676  if (badCFG)
2677  return nullptr;
2678  }
2679  blockAfterStaticInit = Succ;
2680  }
2681 
2682  // Destructors of temporaries in initialization expression should be called
2683  // after initialization finishes.
2684  Expr *Init = VD->getInit();
2685  if (Init) {
2686  HasTemporaries = isa<ExprWithCleanups>(Init);
2687 
2688  if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
2689  // Generate destructors for temporaries in initialization expression.
2690  TempDtorContext Context;
2691  VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
2692  /*BindToTemporary=*/false, Context);
2693  }
2694  }
2695 
2696  autoCreateBlock();
2697  appendStmt(Block, DS);
2698 
2699  findConstructionContexts(
2700  ConstructionContextLayer::create(cfg->getBumpVectorContext(), DS),
2701  Init);
2702 
2703  // Keep track of the last non-null block, as 'Block' can be nulled out
2704  // if the initializer expression is something like a 'while' in a
2705  // statement-expression.
2706  CFGBlock *LastBlock = Block;
2707 
2708  if (Init) {
2709  if (HasTemporaries) {
2710  // For expression with temporaries go directly to subexpression to omit
2711  // generating destructors for the second time.
2712  ExprWithCleanups *EC = cast<ExprWithCleanups>(Init);
2713  if (CFGBlock *newBlock = Visit(EC->getSubExpr()))
2714  LastBlock = newBlock;
2715  }
2716  else {
2717  if (CFGBlock *newBlock = Visit(Init))
2718  LastBlock = newBlock;
2719  }
2720  }
2721 
2722  // If the type of VD is a VLA, then we must process its size expressions.
2723  for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr());
2724  VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr())) {
2725  if (CFGBlock *newBlock = addStmt(VA->getSizeExpr()))
2726  LastBlock = newBlock;
2727  }
2728 
2729  maybeAddScopeBeginForVarDecl(Block, VD, DS);
2730 
2731  // Remove variable from local scope.
2732  if (ScopePos && VD == *ScopePos)
2733  ++ScopePos;
2734 
2735  CFGBlock *B = LastBlock;
2736  if (blockAfterStaticInit) {
2737  Succ = B;
2738  Block = createBlock(false);
2739  Block->setTerminator(DS);
2740  addSuccessor(Block, blockAfterStaticInit);
2741  addSuccessor(Block, B);
2742  B = Block;
2743  }
2744 
2745  return B;
2746 }
2747 
2748 CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) {
2749  // We may see an if statement in the middle of a basic block, or it may be the
2750  // first statement we are processing. In either case, we create a new basic
2751  // block. First, we create the blocks for the then...else statements, and
2752  // then we create the block containing the if statement. If we were in the
2753  // middle of a block, we stop processing that block. That block is then the
2754  // implicit successor for the "then" and "else" clauses.
2755 
2756  // Save local scope position because in case of condition variable ScopePos
2757  // won't be restored when traversing AST.
2758  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2759 
2760  // Create local scope for C++17 if init-stmt if one exists.
2761  if (Stmt *Init = I->getInit())
2762  addLocalScopeForStmt(Init);
2763 
2764  // Create local scope for possible condition variable.
2765  // Store scope position. Add implicit destructor.
2766  if (VarDecl *VD = I->getConditionVariable())
2767  addLocalScopeForVarDecl(VD);
2768 
2769  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), I);
2770 
2771  // The block we were processing is now finished. Make it the successor
2772  // block.
2773  if (Block) {
2774  Succ = Block;
2775  if (badCFG)
2776  return nullptr;
2777  }
2778 
2779  // Process the false branch.
2780  CFGBlock *ElseBlock = Succ;
2781 
2782  if (Stmt *Else = I->getElse()) {
2783  SaveAndRestore<CFGBlock*> sv(Succ);
2784 
2785  // NULL out Block so that the recursive call to Visit will
2786  // create a new basic block.
2787  Block = nullptr;
2788 
2789  // If branch is not a compound statement create implicit scope
2790  // and add destructors.
2791  if (!isa<CompoundStmt>(Else))
2792  addLocalScopeAndDtors(Else);
2793 
2794  ElseBlock = addStmt(Else);
2795 
2796  if (!ElseBlock) // Can occur when the Else body has all NullStmts.
2797  ElseBlock = sv.get();
2798  else if (Block) {
2799  if (badCFG)
2800  return nullptr;
2801  }
2802  }
2803 
2804  // Process the true branch.
2805  CFGBlock *ThenBlock;
2806  {
2807  Stmt *Then = I->getThen();
2808  assert(Then);
2809  SaveAndRestore<CFGBlock*> sv(Succ);
2810  Block = nullptr;
2811 
2812  // If branch is not a compound statement create implicit scope
2813  // and add destructors.
2814  if (!isa<CompoundStmt>(Then))
2815  addLocalScopeAndDtors(Then);
2816 
2817  ThenBlock = addStmt(Then);
2818 
2819  if (!ThenBlock) {
2820  // We can reach here if the "then" body has all NullStmts.
2821  // Create an empty block so we can distinguish between true and false
2822  // branches in path-sensitive analyses.
2823  ThenBlock = createBlock(false);
2824  addSuccessor(ThenBlock, sv.get());
2825  } else if (Block) {
2826  if (badCFG)
2827  return nullptr;
2828  }
2829  }
2830 
2831  // Specially handle "if (expr1 || ...)" and "if (expr1 && ...)" by
2832  // having these handle the actual control-flow jump. Note that
2833  // if we introduce a condition variable, e.g. "if (int x = exp1 || exp2)"
2834  // we resort to the old control-flow behavior. This special handling
2835  // removes infeasible paths from the control-flow graph by having the
2836  // control-flow transfer of '&&' or '||' go directly into the then/else
2837  // blocks directly.
2838  BinaryOperator *Cond =
2840  ? nullptr
2841  : dyn_cast<BinaryOperator>(I->getCond()->IgnoreParens());
2842  CFGBlock *LastBlock;
2843  if (Cond && Cond->isLogicalOp())
2844  LastBlock = VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first;
2845  else {
2846  // Now create a new block containing the if statement.
2847  Block = createBlock(false);
2848 
2849  // Set the terminator of the new block to the If statement.
2850  Block->setTerminator(I);
2851 
2852  // See if this is a known constant.
2853  const TryResult &KnownVal = tryEvaluateBool(I->getCond());
2854 
2855  // Add the successors. If we know that specific branches are
2856  // unreachable, inform addSuccessor() of that knowledge.
2857  addSuccessor(Block, ThenBlock, /* isReachable = */ !KnownVal.isFalse());
2858  addSuccessor(Block, ElseBlock, /* isReachable = */ !KnownVal.isTrue());
2859 
2860  // Add the condition as the last statement in the new block. This may
2861  // create new blocks as the condition may contain control-flow. Any newly
2862  // created blocks will be pointed to be "Block".
2863  LastBlock = addStmt(I->getCond());
2864 
2865  // If the IfStmt contains a condition variable, add it and its
2866  // initializer to the CFG.
2867  if (const DeclStmt* DS = I->getConditionVariableDeclStmt()) {
2868  autoCreateBlock();
2869  LastBlock = addStmt(const_cast<DeclStmt *>(DS));
2870  }
2871  }
2872 
2873  // Finally, if the IfStmt contains a C++17 init-stmt, add it to the CFG.
2874  if (Stmt *Init = I->getInit()) {
2875  autoCreateBlock();
2876  LastBlock = addStmt(Init);
2877  }
2878 
2879  return LastBlock;
2880 }
2881 
2882 CFGBlock *CFGBuilder::VisitReturnStmt(ReturnStmt *R) {
2883  // If we were in the middle of a block we stop processing that block.
2884  //
2885  // NOTE: If a "return" appears in the middle of a block, this means that the
2886  // code afterwards is DEAD (unreachable). We still keep a basic block
2887  // for that code; a simple "mark-and-sweep" from the entry block will be
2888  // able to report such dead blocks.
2889 
2890  // Create the new block.
2891  Block = createBlock(false);
2892 
2893  addAutomaticObjHandling(ScopePos, LocalScope::const_iterator(), R);
2894 
2895  findConstructionContexts(
2896  ConstructionContextLayer::create(cfg->getBumpVectorContext(), R),
2897  R->getRetValue());
2898 
2899  // If the one of the destructors does not return, we already have the Exit
2900  // block as a successor.
2901  if (!Block->hasNoReturnElement())
2902  addSuccessor(Block, &cfg->getExit());
2903 
2904  // Add the return statement to the block. This may create new blocks if R
2905  // contains control-flow (short-circuit operations).
2906  return VisitStmt(R, AddStmtChoice::AlwaysAdd);
2907 }
2908 
2909 CFGBlock *CFGBuilder::VisitSEHExceptStmt(SEHExceptStmt *ES) {
2910  // SEHExceptStmt are treated like labels, so they are the first statement in a
2911  // block.
2912 
2913  // Save local scope position because in case of exception variable ScopePos
2914  // won't be restored when traversing AST.
2915  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2916 
2917  addStmt(ES->getBlock());
2918  CFGBlock *SEHExceptBlock = Block;
2919  if (!SEHExceptBlock)
2920  SEHExceptBlock = createBlock();
2921 
2922  appendStmt(SEHExceptBlock, ES);
2923 
2924  // Also add the SEHExceptBlock as a label, like with regular labels.
2925  SEHExceptBlock->setLabel(ES);
2926 
2927  // Bail out if the CFG is bad.
2928  if (badCFG)
2929  return nullptr;
2930 
2931  // We set Block to NULL to allow lazy creation of a new block (if necessary).
2932  Block = nullptr;
2933 
2934  return SEHExceptBlock;
2935 }
2936 
2937 CFGBlock *CFGBuilder::VisitSEHFinallyStmt(SEHFinallyStmt *FS) {
2938  return VisitCompoundStmt(FS->getBlock());
2939 }
2940 
2941 CFGBlock *CFGBuilder::VisitSEHLeaveStmt(SEHLeaveStmt *LS) {
2942  // "__leave" is a control-flow statement. Thus we stop processing the current
2943  // block.
2944  if (badCFG)
2945  return nullptr;
2946 
2947  // Now create a new block that ends with the __leave statement.
2948  Block = createBlock(false);
2949  Block->setTerminator(LS);
2950 
2951  // If there is no target for the __leave, then we are looking at an incomplete
2952  // AST. This means that the CFG cannot be constructed.
2953  if (SEHLeaveJumpTarget.block) {
2954  addAutomaticObjHandling(ScopePos, SEHLeaveJumpTarget.scopePosition, LS);
2955  addSuccessor(Block, SEHLeaveJumpTarget.block);
2956  } else
2957  badCFG = true;
2958 
2959  return Block;
2960 }
2961 
2962 CFGBlock *CFGBuilder::VisitSEHTryStmt(SEHTryStmt *Terminator) {
2963  // "__try"/"__except"/"__finally" is a control-flow statement. Thus we stop
2964  // processing the current block.
2965  CFGBlock *SEHTrySuccessor = nullptr;
2966 
2967  if (Block) {
2968  if (badCFG)
2969  return nullptr;
2970  SEHTrySuccessor = Block;
2971  } else SEHTrySuccessor = Succ;
2972 
2973  // FIXME: Implement __finally support.
2974  if (Terminator->getFinallyHandler())
2975  return NYS();
2976 
2977  CFGBlock *PrevSEHTryTerminatedBlock = TryTerminatedBlock;
2978 
2979  // Create a new block that will contain the __try statement.
2980  CFGBlock *NewTryTerminatedBlock = createBlock(false);
2981 
2982  // Add the terminator in the __try block.
2983  NewTryTerminatedBlock->setTerminator(Terminator);
2984 
2985  if (SEHExceptStmt *Except = Terminator->getExceptHandler()) {
2986  // The code after the try is the implicit successor if there's an __except.
2987  Succ = SEHTrySuccessor;
2988  Block = nullptr;
2989  CFGBlock *ExceptBlock = VisitSEHExceptStmt(Except);
2990  if (!ExceptBlock)
2991  return nullptr;
2992  // Add this block to the list of successors for the block with the try
2993  // statement.
2994  addSuccessor(NewTryTerminatedBlock, ExceptBlock);
2995  }
2996  if (PrevSEHTryTerminatedBlock)
2997  addSuccessor(NewTryTerminatedBlock, PrevSEHTryTerminatedBlock);
2998  else
2999  addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
3000 
3001  // The code after the try is the implicit successor.
3002  Succ = SEHTrySuccessor;
3003 
3004  // Save the current "__try" context.
3005  SaveAndRestore<CFGBlock *> save_try(TryTerminatedBlock,
3006  NewTryTerminatedBlock);
3007  cfg->addTryDispatchBlock(TryTerminatedBlock);
3008 
3009  // Save the current value for the __leave target.
3010  // All __leaves should go to the code following the __try
3011  // (FIXME: or if the __try has a __finally, to the __finally.)
3012  SaveAndRestore<JumpTarget> save_break(SEHLeaveJumpTarget);
3013  SEHLeaveJumpTarget = JumpTarget(SEHTrySuccessor, ScopePos);
3014 
3015  assert(Terminator->getTryBlock() && "__try must contain a non-NULL body");
3016  Block = nullptr;
3017  return addStmt(Terminator->getTryBlock());
3018 }
3019 
3020 CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) {
3021  // Get the block of the labeled statement. Add it to our map.
3022  addStmt(L->getSubStmt());
3023  CFGBlock *LabelBlock = Block;
3024 
3025  if (!LabelBlock) // This can happen when the body is empty, i.e.
3026  LabelBlock = createBlock(); // scopes that only contains NullStmts.
3027 
3028  assert(LabelMap.find(L->getDecl()) == LabelMap.end() &&
3029  "label already in map");
3030  LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos);
3031 
3032  // Labels partition blocks, so this is the end of the basic block we were
3033  // processing (L is the block's label). Because this is label (and we have
3034  // already processed the substatement) there is no extra control-flow to worry
3035  // about.
3036  LabelBlock->setLabel(L);
3037  if (badCFG)
3038  return nullptr;
3039 
3040  // We set Block to NULL to allow lazy creation of a new block (if necessary);
3041  Block = nullptr;
3042 
3043  // This block is now the implicit successor of other blocks.
3044  Succ = LabelBlock;
3045 
3046  return LabelBlock;
3047 }
3048 
3049 CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) {
3050  CFGBlock *LastBlock = VisitNoRecurse(E, asc);
3051  for (const BlockDecl::Capture &CI : E->getBlockDecl()->captures()) {
3052  if (Expr *CopyExpr = CI.getCopyExpr()) {
3053  CFGBlock *Tmp = Visit(CopyExpr);
3054  if (Tmp)
3055  LastBlock = Tmp;
3056  }
3057  }
3058  return LastBlock;
3059 }
3060 
3061 CFGBlock *CFGBuilder::VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc) {
3062  CFGBlock *LastBlock = VisitNoRecurse(E, asc);
3064  et = E->capture_init_end(); it != et; ++it) {
3065  if (Expr *Init = *it) {
3066  CFGBlock *Tmp = Visit(Init);
3067  if (Tmp)
3068  LastBlock = Tmp;
3069  }
3070  }
3071  return LastBlock;
3072 }
3073 
3074 CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) {
3075  // Goto is a control-flow statement. Thus we stop processing the current
3076  // block and create a new one.
3077 
3078  Block = createBlock(false);
3079  Block->setTerminator(G);
3080 
3081  // If we already know the mapping to the label block add the successor now.
3082  LabelMapTy::iterator I = LabelMap.find(G->getLabel());
3083 
3084  if (I == LabelMap.end())
3085  // We will need to backpatch this block later.
3086  BackpatchBlocks.push_back(JumpSource(Block, ScopePos));
3087  else {
3088  JumpTarget JT = I->second;
3089  addAutomaticObjHandling(ScopePos, JT.scopePosition, G);
3090  addSuccessor(Block, JT.block);
3091  }
3092 
3093  return Block;
3094 }
3095 
3096 CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) {
3097  CFGBlock *LoopSuccessor = nullptr;
3098 
3099  // Save local scope position because in case of condition variable ScopePos
3100  // won't be restored when traversing AST.
3101  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3102 
3103  // Create local scope for init statement and possible condition variable.
3104  // Add destructor for init statement and condition variable.
3105  // Store scope position for continue statement.
3106  if (Stmt *Init = F->getInit())
3107  addLocalScopeForStmt(Init);
3108  LocalScope::const_iterator LoopBeginScopePos = ScopePos;
3109 
3110  if (VarDecl *VD = F->getConditionVariable())
3111  addLocalScopeForVarDecl(VD);
3112  LocalScope::const_iterator ContinueScopePos = ScopePos;
3113 
3114  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), F);
3115 
3116  addLoopExit(F);
3117 
3118  // "for" is a control-flow statement. Thus we stop processing the current
3119  // block.
3120  if (Block) {
3121  if (badCFG)
3122  return nullptr;
3123  LoopSuccessor = Block;
3124  } else
3125  LoopSuccessor = Succ;
3126 
3127  // Save the current value for the break targets.
3128  // All breaks should go to the code following the loop.
3129  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3130  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3131 
3132  CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
3133 
3134  // Now create the loop body.
3135  {
3136  assert(F->getBody());
3137 
3138  // Save the current values for Block, Succ, continue and break targets.
3139  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3140  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
3141 
3142  // Create an empty block to represent the transition block for looping back
3143  // to the head of the loop. If we have increment code, it will
3144  // go in this block as well.
3145  Block = Succ = TransitionBlock = createBlock(false);
3146  TransitionBlock->setLoopTarget(F);
3147 
3148  if (Stmt *I = F->getInc()) {
3149  // Generate increment code in its own basic block. This is the target of
3150  // continue statements.
3151  Succ = addStmt(I);
3152  }
3153 
3154  // Finish up the increment (or empty) block if it hasn't been already.
3155  if (Block) {
3156  assert(Block == Succ);
3157  if (badCFG)
3158  return nullptr;
3159  Block = nullptr;
3160  }
3161 
3162  // The starting block for the loop increment is the block that should
3163  // represent the 'loop target' for looping back to the start of the loop.
3164  ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
3165  ContinueJumpTarget.block->setLoopTarget(F);
3166 
3167  // Loop body should end with destructor of Condition variable (if any).
3168  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, F);
3169 
3170  // If body is not a compound statement create implicit scope
3171  // and add destructors.
3172  if (!isa<CompoundStmt>(F->getBody()))
3173  addLocalScopeAndDtors(F->getBody());
3174 
3175  // Now populate the body block, and in the process create new blocks as we
3176  // walk the body of the loop.
3177  BodyBlock = addStmt(F->getBody());
3178 
3179  if (!BodyBlock) {
3180  // In the case of "for (...;...;...);" we can have a null BodyBlock.
3181  // Use the continue jump target as the proxy for the body.
3182  BodyBlock = ContinueJumpTarget.block;
3183  }
3184  else if (badCFG)
3185  return nullptr;
3186  }
3187 
3188  // Because of short-circuit evaluation, the condition of the loop can span
3189  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3190  // evaluate the condition.
3191  CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
3192 
3193  do {
3194  Expr *C = F->getCond();
3195  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3196 
3197  // Specially handle logical operators, which have a slightly
3198  // more optimal CFG representation.
3199  if (BinaryOperator *Cond =
3200  dyn_cast_or_null<BinaryOperator>(C ? C->IgnoreParens() : nullptr))
3201  if (Cond->isLogicalOp()) {
3202  std::tie(EntryConditionBlock, ExitConditionBlock) =
3203  VisitLogicalOperator(Cond, F, BodyBlock, LoopSuccessor);
3204  break;
3205  }
3206 
3207  // The default case when not handling logical operators.
3208  EntryConditionBlock = ExitConditionBlock = createBlock(false);
3209  ExitConditionBlock->setTerminator(F);
3210 
3211  // See if this is a known constant.
3212  TryResult KnownVal(true);
3213 
3214  if (C) {
3215  // Now add the actual condition to the condition block.
3216  // Because the condition itself may contain control-flow, new blocks may
3217  // be created. Thus we update "Succ" after adding the condition.
3218  Block = ExitConditionBlock;
3219  EntryConditionBlock = addStmt(C);
3220 
3221  // If this block contains a condition variable, add both the condition
3222  // variable and initializer to the CFG.
3223  if (VarDecl *VD = F->getConditionVariable()) {
3224  if (Expr *Init = VD->getInit()) {
3225  autoCreateBlock();
3226  const DeclStmt *DS = F->getConditionVariableDeclStmt();
3227  assert(DS->isSingleDecl());
3228  findConstructionContexts(
3229  ConstructionContextLayer::create(cfg->getBumpVectorContext(), DS),
3230  Init);
3231  appendStmt(Block, DS);
3232  EntryConditionBlock = addStmt(Init);
3233  assert(Block == EntryConditionBlock);
3234  maybeAddScopeBeginForVarDecl(EntryConditionBlock, VD, C);
3235  }
3236  }
3237 
3238  if (Block && badCFG)
3239  return nullptr;
3240 
3241  KnownVal = tryEvaluateBool(C);
3242  }
3243 
3244  // Add the loop body entry as a successor to the condition.
3245  addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
3246  // Link up the condition block with the code that follows the loop. (the
3247  // false branch).
3248  addSuccessor(ExitConditionBlock,
3249  KnownVal.isTrue() ? nullptr : LoopSuccessor);
3250  } while (false);
3251 
3252  // Link up the loop-back block to the entry condition block.
3253  addSuccessor(TransitionBlock, EntryConditionBlock);
3254 
3255  // The condition block is the implicit successor for any code above the loop.
3256  Succ = EntryConditionBlock;
3257 
3258  // If the loop contains initialization, create a new block for those
3259  // statements. This block can also contain statements that precede the loop.
3260  if (Stmt *I = F->getInit()) {
3261  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3262  ScopePos = LoopBeginScopePos;
3263  Block = createBlock();
3264  return addStmt(I);
3265  }
3266 
3267  // There is no loop initialization. We are thus basically a while loop.
3268  // NULL out Block to force lazy block construction.
3269  Block = nullptr;
3270  Succ = EntryConditionBlock;
3271  return EntryConditionBlock;
3272 }
3273 
3274 CFGBlock *
3275 CFGBuilder::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *MTE,
3276  AddStmtChoice asc) {
3277  findConstructionContexts(
3278  ConstructionContextLayer::create(cfg->getBumpVectorContext(), MTE),
3279  MTE->getTemporary());
3280 
3281  return VisitStmt(MTE, asc);
3282 }
3283 
3284 CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) {
3285  if (asc.alwaysAdd(*this, M)) {
3286  autoCreateBlock();
3287  appendStmt(Block, M);
3288  }
3289  return Visit(M->getBase());
3290 }
3291 
3292 CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) {
3293  // Objective-C fast enumeration 'for' statements:
3294  // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC
3295  //
3296  // for ( Type newVariable in collection_expression ) { statements }
3297  //
3298  // becomes:
3299  //
3300  // prologue:
3301  // 1. collection_expression
3302  // T. jump to loop_entry
3303  // loop_entry:
3304  // 1. side-effects of element expression
3305  // 1. ObjCForCollectionStmt [performs binding to newVariable]
3306  // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil]
3307  // TB:
3308  // statements
3309  // T. jump to loop_entry
3310  // FB:
3311  // what comes after
3312  //
3313  // and
3314  //
3315  // Type existingItem;
3316  // for ( existingItem in expression ) { statements }
3317  //
3318  // becomes:
3319  //
3320  // the same with newVariable replaced with existingItem; the binding works
3321  // the same except that for one ObjCForCollectionStmt::getElement() returns
3322  // a DeclStmt and the other returns a DeclRefExpr.
3323 
3324  CFGBlock *LoopSuccessor = nullptr;
3325 
3326  if (Block) {
3327  if (badCFG)
3328  return nullptr;
3329  LoopSuccessor = Block;
3330  Block = nullptr;
3331  } else
3332  LoopSuccessor = Succ;
3333 
3334  // Build the condition blocks.
3335  CFGBlock *ExitConditionBlock = createBlock(false);
3336 
3337  // Set the terminator for the "exit" condition block.
3338  ExitConditionBlock->setTerminator(S);
3339 
3340  // The last statement in the block should be the ObjCForCollectionStmt, which
3341  // performs the actual binding to 'element' and determines if there are any
3342  // more items in the collection.
3343  appendStmt(ExitConditionBlock, S);
3344  Block = ExitConditionBlock;
3345 
3346  // Walk the 'element' expression to see if there are any side-effects. We
3347  // generate new blocks as necessary. We DON'T add the statement by default to
3348  // the CFG unless it contains control-flow.
3349  CFGBlock *EntryConditionBlock = Visit(S->getElement(),
3350  AddStmtChoice::NotAlwaysAdd);
3351  if (Block) {
3352  if (badCFG)
3353  return nullptr;
3354  Block = nullptr;
3355  }
3356 
3357  // The condition block is the implicit successor for the loop body as well as
3358  // any code above the loop.
3359  Succ = EntryConditionBlock;
3360 
3361  // Now create the true branch.
3362  {
3363  // Save the current values for Succ, continue and break targets.
3364  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3365  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3366  save_break(BreakJumpTarget);
3367 
3368  // Add an intermediate block between the BodyBlock and the
3369  // EntryConditionBlock to represent the "loop back" transition, for looping
3370  // back to the head of the loop.
3371  CFGBlock *LoopBackBlock = nullptr;
3372  Succ = LoopBackBlock = createBlock();
3373  LoopBackBlock->setLoopTarget(S);
3374 
3375  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3376  ContinueJumpTarget = JumpTarget(Succ, ScopePos);
3377 
3378  CFGBlock *BodyBlock = addStmt(S->getBody());
3379 
3380  if (!BodyBlock)
3381  BodyBlock = ContinueJumpTarget.block; // can happen for "for (X in Y) ;"
3382  else if (Block) {
3383  if (badCFG)
3384  return nullptr;
3385  }
3386 
3387  // This new body block is a successor to our "exit" condition block.
3388  addSuccessor(ExitConditionBlock, BodyBlock);
3389  }
3390 
3391  // Link up the condition block with the code that follows the loop.
3392  // (the false branch).
3393  addSuccessor(ExitConditionBlock, LoopSuccessor);
3394 
3395  // Now create a prologue block to contain the collection expression.
3396  Block = createBlock();
3397  return addStmt(S->getCollection());
3398 }
3399 
3400 CFGBlock *CFGBuilder::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) {
3401  // Inline the body.
3402  return addStmt(S->getSubStmt());
3403  // TODO: consider adding cleanups for the end of @autoreleasepool scope.
3404 }
3405 
3406 CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) {
3407  // FIXME: Add locking 'primitives' to CFG for @synchronized.
3408 
3409  // Inline the body.
3410  CFGBlock *SyncBlock = addStmt(S->getSynchBody());
3411 
3412  // The sync body starts its own basic block. This makes it a little easier
3413  // for diagnostic clients.
3414  if (SyncBlock) {
3415  if (badCFG)
3416  return nullptr;
3417 
3418  Block = nullptr;
3419  Succ = SyncBlock;
3420  }
3421 
3422  // Add the @synchronized to the CFG.
3423  autoCreateBlock();
3424  appendStmt(Block, S);
3425 
3426  // Inline the sync expression.
3427  return addStmt(S->getSynchExpr());
3428 }
3429 
3430 CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) {
3431  // FIXME
3432  return NYS();
3433 }
3434 
3435 CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) {
3436  autoCreateBlock();
3437 
3438  // Add the PseudoObject as the last thing.
3439  appendStmt(Block, E);
3440 
3441  CFGBlock *lastBlock = Block;
3442 
3443  // Before that, evaluate all of the semantics in order. In
3444  // CFG-land, that means appending them in reverse order.
3445  for (unsigned i = E->getNumSemanticExprs(); i != 0; ) {
3446  Expr *Semantic = E->getSemanticExpr(--i);
3447 
3448  // If the semantic is an opaque value, we're being asked to bind
3449  // it to its source expression.
3450  if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
3451  Semantic = OVE->getSourceExpr();
3452 
3453  if (CFGBlock *B = Visit(Semantic))
3454  lastBlock = B;
3455  }
3456 
3457  return lastBlock;
3458 }
3459 
3460 CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) {
3461  CFGBlock *LoopSuccessor = nullptr;
3462 
3463  // Save local scope position because in case of condition variable ScopePos
3464  // won't be restored when traversing AST.
3465  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3466 
3467  // Create local scope for possible condition variable.
3468  // Store scope position for continue statement.
3469  LocalScope::const_iterator LoopBeginScopePos = ScopePos;
3470  if (VarDecl *VD = W->getConditionVariable()) {
3471  addLocalScopeForVarDecl(VD);
3472  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3473  }
3474  addLoopExit(W);
3475 
3476  // "while" is a control-flow statement. Thus we stop processing the current
3477  // block.
3478  if (Block) {
3479  if (badCFG)
3480  return nullptr;
3481  LoopSuccessor = Block;
3482  Block = nullptr;
3483  } else {
3484  LoopSuccessor = Succ;
3485  }
3486 
3487  CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
3488 
3489  // Process the loop body.
3490  {
3491  assert(W->getBody());
3492 
3493  // Save the current values for Block, Succ, continue and break targets.
3494  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3495  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3496  save_break(BreakJumpTarget);
3497 
3498  // Create an empty block to represent the transition block for looping back
3499  // to the head of the loop.
3500  Succ = TransitionBlock = createBlock(false);
3501  TransitionBlock->setLoopTarget(W);
3502  ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos);
3503 
3504  // All breaks should go to the code following the loop.
3505  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3506 
3507  // Loop body should end with destructor of Condition variable (if any).
3508  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3509 
3510  // If body is not a compound statement create implicit scope
3511  // and add destructors.
3512  if (!isa<CompoundStmt>(W->getBody()))
3513  addLocalScopeAndDtors(W->getBody());
3514 
3515  // Create the body. The returned block is the entry to the loop body.
3516  BodyBlock = addStmt(W->getBody());
3517 
3518  if (!BodyBlock)
3519  BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;"
3520  else if (Block && badCFG)
3521  return nullptr;
3522  }
3523 
3524  // Because of short-circuit evaluation, the condition of the loop can span
3525  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3526  // evaluate the condition.
3527  CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
3528 
3529  do {
3530  Expr *C = W->getCond();
3531 
3532  // Specially handle logical operators, which have a slightly
3533  // more optimal CFG representation.
3534  if (BinaryOperator *Cond = dyn_cast<BinaryOperator>(C->IgnoreParens()))
3535  if (Cond->isLogicalOp()) {
3536  std::tie(EntryConditionBlock, ExitConditionBlock) =
3537  VisitLogicalOperator(Cond, W, BodyBlock, LoopSuccessor);
3538  break;
3539  }
3540 
3541  // The default case when not handling logical operators.
3542  ExitConditionBlock = createBlock(false);
3543  ExitConditionBlock->setTerminator(W);
3544 
3545  // Now add the actual condition to the condition block.
3546  // Because the condition itself may contain control-flow, new blocks may
3547  // be created. Thus we update "Succ" after adding the condition.
3548  Block = ExitConditionBlock;
3549  Block = EntryConditionBlock = addStmt(C);
3550 
3551  // If this block contains a condition variable, add both the condition
3552  // variable and initializer to the CFG.
3553  if (VarDecl *VD = W->getConditionVariable()) {
3554  if (Expr *Init = VD->getInit()) {
3555  autoCreateBlock();
3556  const DeclStmt *DS = W->getConditionVariableDeclStmt();
3557  assert(DS->isSingleDecl());
3558  findConstructionContexts(
3559  ConstructionContextLayer::create(cfg->getBumpVectorContext(),
3560  const_cast<DeclStmt *>(DS)),
3561  Init);
3562  appendStmt(Block, DS);
3563  EntryConditionBlock = addStmt(Init);
3564  assert(Block == EntryConditionBlock);
3565  maybeAddScopeBeginForVarDecl(EntryConditionBlock, VD, C);
3566  }
3567  }
3568 
3569  if (Block && badCFG)
3570  return nullptr;
3571 
3572  // See if this is a known constant.
3573  const TryResult& KnownVal = tryEvaluateBool(C);
3574 
3575  // Add the loop body entry as a successor to the condition.
3576  addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
3577  // Link up the condition block with the code that follows the loop. (the
3578  // false branch).
3579  addSuccessor(ExitConditionBlock,
3580  KnownVal.isTrue() ? nullptr : LoopSuccessor);
3581  } while(false);
3582 
3583  // Link up the loop-back block to the entry condition block.
3584  addSuccessor(TransitionBlock, EntryConditionBlock);
3585 
3586  // There can be no more statements in the condition block since we loop back
3587  // to this block. NULL out Block to force lazy creation of another block.
3588  Block = nullptr;
3589 
3590  // Return the condition block, which is the dominating block for the loop.
3591  Succ = EntryConditionBlock;
3592  return EntryConditionBlock;
3593 }
3594 
3595 CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) {
3596  // FIXME: For now we pretend that @catch and the code it contains does not
3597  // exit.
3598  return Block;
3599 }
3600 
3601 CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) {
3602  // FIXME: This isn't complete. We basically treat @throw like a return
3603  // statement.
3604 
3605  // If we were in the middle of a block we stop processing that block.
3606  if (badCFG)
3607  return nullptr;
3608 
3609  // Create the new block.
3610  Block = createBlock(false);
3611 
3612  // The Exit block is the only successor.
3613  addSuccessor(Block, &cfg->getExit());
3614 
3615  // Add the statement to the block. This may create new blocks if S contains
3616  // control-flow (short-circuit operations).
3617  return VisitStmt(S, AddStmtChoice::AlwaysAdd);
3618 }
3619 
3620 CFGBlock *CFGBuilder::VisitObjCMessageExpr(ObjCMessageExpr *ME,
3621  AddStmtChoice asc) {
3622  findConstructionContextsForArguments(ME);
3623 
3624  autoCreateBlock();
3625  appendObjCMessage(Block, ME);
3626 
3627  return VisitChildren(ME);
3628 }
3629 
3630 CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) {
3631  // If we were in the middle of a block we stop processing that block.
3632  if (badCFG)
3633  return nullptr;
3634 
3635  // Create the new block.
3636  Block = createBlock(false);
3637 
3638  if (TryTerminatedBlock)
3639  // The current try statement is the only successor.
3640  addSuccessor(Block, TryTerminatedBlock);
3641  else
3642  // otherwise the Exit block is the only successor.
3643  addSuccessor(Block, &cfg->getExit());
3644 
3645  // Add the statement to the block. This may create new blocks if S contains
3646  // control-flow (short-circuit operations).
3647  return VisitStmt(T, AddStmtChoice::AlwaysAdd);
3648 }
3649 
3650 CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) {
3651  CFGBlock *LoopSuccessor = nullptr;
3652 
3653  addLoopExit(D);
3654 
3655  // "do...while" is a control-flow statement. Thus we stop processing the
3656  // current block.
3657  if (Block) {
3658  if (badCFG)
3659  return nullptr;
3660  LoopSuccessor = Block;
3661  } else
3662  LoopSuccessor = Succ;
3663 
3664  // Because of short-circuit evaluation, the condition of the loop can span
3665  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3666  // evaluate the condition.
3667  CFGBlock *ExitConditionBlock = createBlock(false);
3668  CFGBlock *EntryConditionBlock = ExitConditionBlock;
3669 
3670  // Set the terminator for the "exit" condition block.
3671  ExitConditionBlock->setTerminator(D);
3672 
3673  // Now add the actual condition to the condition block. Because the condition
3674  // itself may contain control-flow, new blocks may be created.
3675  if (Stmt *C = D->getCond()) {
3676  Block = ExitConditionBlock;
3677  EntryConditionBlock = addStmt(C);
3678  if (Block) {
3679  if (badCFG)
3680  return nullptr;
3681  }
3682  }
3683 
3684  // The condition block is the implicit successor for the loop body.
3685  Succ = EntryConditionBlock;
3686 
3687  // See if this is a known constant.
3688  const TryResult &KnownVal = tryEvaluateBool(D->getCond());
3689 
3690  // Process the loop body.
3691  CFGBlock *BodyBlock = nullptr;
3692  {
3693  assert(D->getBody());
3694 
3695  // Save the current values for Block, Succ, and continue and break targets
3696  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3697  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3698  save_break(BreakJumpTarget);
3699 
3700  // All continues within this loop should go to the condition block
3701  ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos);
3702 
3703  // All breaks should go to the code following the loop.
3704  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3705 
3706  // NULL out Block to force lazy instantiation of blocks for the body.
3707  Block = nullptr;
3708 
3709  // If body is not a compound statement create implicit scope
3710  // and add destructors.
3711  if (!isa<CompoundStmt>(D->getBody()))
3712  addLocalScopeAndDtors(D->getBody());
3713 
3714  // Create the body. The returned block is the entry to the loop body.
3715  BodyBlock = addStmt(D->getBody());
3716 
3717  if (!BodyBlock)
3718  BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)"
3719  else if (Block) {
3720  if (badCFG)
3721  return nullptr;
3722  }
3723 
3724  // Add an intermediate block between the BodyBlock and the
3725  // ExitConditionBlock to represent the "loop back" transition. Create an
3726  // empty block to represent the transition block for looping back to the
3727  // head of the loop.
3728  // FIXME: Can we do this more efficiently without adding another block?
3729  Block = nullptr;
3730  Succ = BodyBlock;
3731  CFGBlock *LoopBackBlock = createBlock();
3732  LoopBackBlock->setLoopTarget(D);
3733 
3734  if (!KnownVal.isFalse())
3735  // Add the loop body entry as a successor to the condition.
3736  addSuccessor(ExitConditionBlock, LoopBackBlock);
3737  else
3738  addSuccessor(ExitConditionBlock, nullptr);
3739  }
3740 
3741  // Link up the condition block with the code that follows the loop.
3742  // (the false branch).
3743  addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
3744 
3745  // There can be no more statements in the body block(s) since we loop back to
3746  // the body. NULL out Block to force lazy creation of another block.
3747  Block = nullptr;
3748 
3749  // Return the loop body, which is the dominating block for the loop.
3750  Succ = BodyBlock;
3751  return BodyBlock;
3752 }
3753 
3754 CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) {
3755  // "continue" is a control-flow statement. Thus we stop processing the
3756  // current block.
3757  if (badCFG)
3758  return nullptr;
3759 
3760  // Now create a new block that ends with the continue statement.
3761  Block = createBlock(false);
3762  Block->setTerminator(C);
3763 
3764  // If there is no target for the continue, then we are looking at an
3765  // incomplete AST. This means the CFG cannot be constructed.
3766  if (ContinueJumpTarget.block) {
3767  addAutomaticObjHandling(ScopePos, ContinueJumpTarget.scopePosition, C);
3768  addSuccessor(Block, ContinueJumpTarget.block);
3769  } else
3770  badCFG = true;
3771 
3772  return Block;
3773 }
3774 
3775 CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
3776  AddStmtChoice asc) {
3777  if (asc.alwaysAdd(*this, E)) {
3778  autoCreateBlock();
3779  appendStmt(Block, E);
3780  }
3781 
3782  // VLA types have expressions that must be evaluated.
3783  CFGBlock *lastBlock = Block;
3784 
3785  if (E->isArgumentType()) {
3786  for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr());
3787  VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr()))
3788  lastBlock = addStmt(VA->getSizeExpr());
3789  }
3790  return lastBlock;
3791 }
3792 
3793 /// VisitStmtExpr - Utility method to handle (nested) statement
3794 /// expressions (a GCC extension).
3795 CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) {
3796  if (asc.alwaysAdd(*this, SE)) {
3797  autoCreateBlock();
3798  appendStmt(Block, SE);
3799  }
3800  return VisitCompoundStmt(SE->getSubStmt());
3801 }
3802 
3803 CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) {
3804  // "switch" is a control-flow statement. Thus we stop processing the current
3805  // block.
3806  CFGBlock *SwitchSuccessor = nullptr;
3807 
3808  // Save local scope position because in case of condition variable ScopePos
3809  // won't be restored when traversing AST.
3810  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3811 
3812  // Create local scope for C++17 switch init-stmt if one exists.
3813  if (Stmt *Init = Terminator->getInit())
3814  addLocalScopeForStmt(Init);
3815 
3816  // Create local scope for possible condition variable.
3817  // Store scope position. Add implicit destructor.
3818  if (VarDecl *VD = Terminator->getConditionVariable())
3819  addLocalScopeForVarDecl(VD);
3820 
3821  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), Terminator);
3822 
3823  if (Block) {
3824  if (badCFG)
3825  return nullptr;
3826  SwitchSuccessor = Block;
3827  } else SwitchSuccessor = Succ;
3828 
3829  // Save the current "switch" context.
3830  SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock),
3831  save_default(DefaultCaseBlock);
3832  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3833 
3834  // Set the "default" case to be the block after the switch statement. If the
3835  // switch statement contains a "default:", this value will be overwritten with
3836  // the block for that code.
3837  DefaultCaseBlock = SwitchSuccessor;
3838 
3839  // Create a new block that will contain the switch statement.
3840  SwitchTerminatedBlock = createBlock(false);
3841 
3842  // Now process the switch body. The code after the switch is the implicit
3843  // successor.
3844  Succ = SwitchSuccessor;
3845  BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos);
3846 
3847  // When visiting the body, the case statements should automatically get linked
3848  // up to the switch. We also don't keep a pointer to the body, since all
3849  // control-flow from the switch goes to case/default statements.
3850  assert(Terminator->getBody() && "switch must contain a non-NULL body");
3851  Block = nullptr;
3852 
3853  // For pruning unreachable case statements, save the current state
3854  // for tracking the condition value.
3855  SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered,
3856  false);
3857 
3858  // Determine if the switch condition can be explicitly evaluated.
3859  assert(Terminator->getCond() && "switch condition must be non-NULL");
3860  Expr::EvalResult result;
3861  bool b = tryEvaluate(Terminator->getCond(), result);
3862  SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond,
3863  b ? &result : nullptr);
3864 
3865  // If body is not a compound statement create implicit scope
3866  // and add destructors.
3867  if (!isa<CompoundStmt>(Terminator->getBody()))
3868  addLocalScopeAndDtors(Terminator->getBody());
3869 
3870  addStmt(Terminator->getBody());
3871  if (Block) {
3872  if (badCFG)
3873  return nullptr;
3874  }
3875 
3876  // If we have no "default:" case, the default transition is to the code
3877  // following the switch body. Moreover, take into account if all the
3878  // cases of a switch are covered (e.g., switching on an enum value).
3879  //
3880  // Note: We add a successor to a switch that is considered covered yet has no
3881  // case statements if the enumeration has no enumerators.
3882  bool SwitchAlwaysHasSuccessor = false;
3883  SwitchAlwaysHasSuccessor |= switchExclusivelyCovered;
3884  SwitchAlwaysHasSuccessor |= Terminator->isAllEnumCasesCovered() &&
3885  Terminator->getSwitchCaseList();
3886  addSuccessor(SwitchTerminatedBlock, DefaultCaseBlock,
3887  !SwitchAlwaysHasSuccessor);
3888 
3889  // Add the terminator and condition in the switch block.
3890  SwitchTerminatedBlock->setTerminator(Terminator);
3891  Block = SwitchTerminatedBlock;
3892  CFGBlock *LastBlock = addStmt(Terminator->getCond());
3893 
3894  // If the SwitchStmt contains a condition variable, add both the
3895  // SwitchStmt and the condition variable initialization to the CFG.
3896  if (VarDecl *VD = Terminator->getConditionVariable()) {
3897  if (Expr *Init = VD->getInit()) {
3898  autoCreateBlock();
3899  appendStmt(Block, Terminator->getConditionVariableDeclStmt());
3900  LastBlock = addStmt(Init);
3901  maybeAddScopeBeginForVarDecl(LastBlock, VD, Init);
3902  }
3903  }
3904 
3905  // Finally, if the SwitchStmt contains a C++17 init-stmt, add it to the CFG.
3906  if (Stmt *Init = Terminator->getInit()) {
3907  autoCreateBlock();
3908  LastBlock = addStmt(Init);
3909  }
3910 
3911  return LastBlock;
3912 }
3913 
3914 static bool shouldAddCase(bool &switchExclusivelyCovered,
3915  const Expr::EvalResult *switchCond,
3916  const CaseStmt *CS,
3917  ASTContext &Ctx) {
3918  if (!switchCond)
3919  return true;
3920 
3921  bool addCase = false;
3922 
3923  if (!switchExclusivelyCovered) {
3924  if (switchCond->Val.isInt()) {
3925  // Evaluate the LHS of the case value.
3926  const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx);
3927  const llvm::APSInt &condInt = switchCond->Val.getInt();
3928 
3929  if (condInt == lhsInt) {
3930  addCase = true;
3931  switchExclusivelyCovered = true;
3932  }
3933  else if (condInt > lhsInt) {
3934  if (const Expr *RHS = CS->getRHS()) {
3935  // Evaluate the RHS of the case value.
3936  const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx);
3937  if (V2 >= condInt) {
3938  addCase = true;
3939  switchExclusivelyCovered = true;
3940  }
3941  }
3942  }
3943  }
3944  else
3945  addCase = true;
3946  }
3947  return addCase;
3948 }
3949 
3950 CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) {
3951  // CaseStmts are essentially labels, so they are the first statement in a
3952  // block.
3953  CFGBlock *TopBlock = nullptr, *LastBlock = nullptr;
3954 
3955  if (Stmt *Sub = CS->getSubStmt()) {
3956  // For deeply nested chains of CaseStmts, instead of doing a recursion
3957  // (which can blow out the stack), manually unroll and create blocks
3958  // along the way.
3959  while (isa<CaseStmt>(Sub)) {
3960  CFGBlock *currentBlock = createBlock(false);
3961  currentBlock->setLabel(CS);
3962 
3963  if (TopBlock)
3964  addSuccessor(LastBlock, currentBlock);
3965  else
3966  TopBlock = currentBlock;
3967 
3968  addSuccessor(SwitchTerminatedBlock,
3969  shouldAddCase(switchExclusivelyCovered, switchCond,
3970  CS, *Context)
3971  ? currentBlock : nullptr);
3972 
3973  LastBlock = currentBlock;
3974  CS = cast<CaseStmt>(Sub);
3975  Sub = CS->getSubStmt();
3976  }
3977 
3978  addStmt(Sub);
3979  }
3980 
3981  CFGBlock *CaseBlock = Block;
3982  if (!CaseBlock)
3983  CaseBlock = createBlock();
3984 
3985  // Cases statements partition blocks, so this is the top of the basic block we
3986  // were processing (the "case XXX:" is the label).
3987  CaseBlock->setLabel(CS);
3988 
3989  if (badCFG)
3990  return nullptr;
3991 
3992  // Add this block to the list of successors for the block with the switch
3993  // statement.
3994  assert(SwitchTerminatedBlock);
3995  addSuccessor(SwitchTerminatedBlock, CaseBlock,
3996  shouldAddCase(switchExclusivelyCovered, switchCond,
3997  CS, *Context));
3998 
3999  // We set Block to NULL to allow lazy creation of a new block (if necessary)
4000  Block = nullptr;
4001 
4002  if (TopBlock) {
4003  addSuccessor(LastBlock, CaseBlock);
4004  Succ = TopBlock;
4005  } else {
4006  // This block is now the implicit successor of other blocks.
4007  Succ = CaseBlock;
4008  }
4009 
4010  return Succ;
4011 }
4012 
4013 CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) {
4014  if (Terminator->getSubStmt())
4015  addStmt(Terminator->getSubStmt());
4016 
4017  DefaultCaseBlock = Block;
4018 
4019  if (!DefaultCaseBlock)
4020  DefaultCaseBlock = createBlock();
4021 
4022  // Default statements partition blocks, so this is the top of the basic block
4023  // we were processing (the "default:" is the label).
4024  DefaultCaseBlock->setLabel(Terminator);
4025 
4026  if (badCFG)
4027  return nullptr;
4028 
4029  // Unlike case statements, we don't add the default block to the successors
4030  // for the switch statement immediately. This is done when we finish
4031  // processing the switch statement. This allows for the default case
4032  // (including a fall-through to the code after the switch statement) to always
4033  // be the last successor of a switch-terminated block.
4034 
4035  // We set Block to NULL to allow lazy creation of a new block (if necessary)
4036  Block = nullptr;
4037 
4038  // This block is now the implicit successor of other blocks.
4039  Succ = DefaultCaseBlock;
4040 
4041  return DefaultCaseBlock;
4042 }
4043 
4044 CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) {
4045  // "try"/"catch" is a control-flow statement. Thus we stop processing the
4046  // current block.
4047  CFGBlock *TrySuccessor = nullptr;
4048 
4049  if (Block) {
4050  if (badCFG)
4051  return nullptr;
4052  TrySuccessor = Block;
4053  } else TrySuccessor = Succ;
4054 
4055  CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock;
4056 
4057  // Create a new block that will contain the try statement.
4058  CFGBlock *NewTryTerminatedBlock = createBlock(false);
4059  // Add the terminator in the try block.
4060  NewTryTerminatedBlock->setTerminator(Terminator);
4061 
4062  bool HasCatchAll = false;
4063  for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) {
4064  // The code after the try is the implicit successor.
4065  Succ = TrySuccessor;
4066  CXXCatchStmt *CS = Terminator->getHandler(h);
4067  if (CS->getExceptionDecl() == nullptr) {
4068  HasCatchAll = true;
4069  }
4070  Block = nullptr;
4071  CFGBlock *CatchBlock = VisitCXXCatchStmt(CS);
4072  if (!CatchBlock)
4073  return nullptr;
4074  // Add this block to the list of successors for the block with the try
4075  // statement.
4076  addSuccessor(NewTryTerminatedBlock, CatchBlock);
4077  }
4078  if (!HasCatchAll) {
4079  if (PrevTryTerminatedBlock)
4080  addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock);
4081  else
4082  addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
4083  }
4084 
4085  // The code after the try is the implicit successor.
4086  Succ = TrySuccessor;
4087 
4088  // Save the current "try" context.
4089  SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock);
4090  cfg->addTryDispatchBlock(TryTerminatedBlock);
4091 
4092  assert(Terminator->getTryBlock() && "try must contain a non-NULL body");
4093  Block = nullptr;
4094  return addStmt(Terminator->getTryBlock());
4095 }
4096 
4097 CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) {
4098  // CXXCatchStmt are treated like labels, so they are the first statement in a
4099  // block.
4100 
4101  // Save local scope position because in case of exception variable ScopePos
4102  // won't be restored when traversing AST.
4103  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
4104 
4105  // Create local scope for possible exception variable.
4106  // Store scope position. Add implicit destructor.
4107  if (VarDecl *VD = CS->getExceptionDecl()) {
4108  LocalScope::const_iterator BeginScopePos = ScopePos;
4109  addLocalScopeForVarDecl(VD);
4110  addAutomaticObjHandling(ScopePos, BeginScopePos, CS);
4111  }
4112 
4113  if (CS->getHandlerBlock())
4114  addStmt(CS->getHandlerBlock());
4115 
4116  CFGBlock *CatchBlock = Block;
4117  if (!CatchBlock)
4118  CatchBlock = createBlock();
4119 
4120  // CXXCatchStmt is more than just a label. They have semantic meaning
4121  // as well, as they implicitly "initialize" the catch variable. Add
4122  // it to the CFG as a CFGElement so that the control-flow of these
4123  // semantics gets captured.
4124  appendStmt(CatchBlock, CS);
4125 
4126  // Also add the CXXCatchStmt as a label, to mirror handling of regular
4127  // labels.
4128  CatchBlock->setLabel(CS);
4129 
4130  // Bail out if the CFG is bad.
4131  if (badCFG)
4132  return nullptr;
4133 
4134  // We set Block to NULL to allow lazy creation of a new block (if necessary)
4135  Block = nullptr;
4136 
4137  return CatchBlock;
4138 }
4139 
4140 CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) {
4141  // C++0x for-range statements are specified as [stmt.ranged]:
4142  //
4143  // {
4144  // auto && __range = range-init;
4145  // for ( auto __begin = begin-expr,
4146  // __end = end-expr;
4147  // __begin != __end;
4148  // ++__begin ) {
4149  // for-range-declaration = *__begin;
4150  // statement
4151  // }
4152  // }
4153 
4154  // Save local scope position before the addition of the implicit variables.
4155  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
4156 
4157  // Create local scopes and destructors for range, begin and end variables.
4158  if (Stmt *Range = S->getRangeStmt())
4159  addLocalScopeForStmt(Range);
4160  if (Stmt *Begin = S->getBeginStmt())
4161  addLocalScopeForStmt(Begin);
4162  if (Stmt *End = S->getEndStmt())
4163  addLocalScopeForStmt(End);
4164  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), S);
4165 
4166  LocalScope::const_iterator ContinueScopePos = ScopePos;
4167 
4168  // "for" is a control-flow statement. Thus we stop processing the current
4169  // block.
4170  CFGBlock *LoopSuccessor = nullptr;
4171  if (Block) {
4172  if (badCFG)
4173  return nullptr;
4174  LoopSuccessor = Block;
4175  } else
4176  LoopSuccessor = Succ;
4177 
4178  // Save the current value for the break targets.
4179  // All breaks should go to the code following the loop.
4180  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
4181  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
4182 
4183  // The block for the __begin != __end expression.
4184  CFGBlock *ConditionBlock = createBlock(false);
4185  ConditionBlock->setTerminator(S);
4186 
4187  // Now add the actual condition to the condition block.
4188  if (Expr *C = S->getCond()) {
4189  Block = ConditionBlock;
4190  CFGBlock *BeginConditionBlock = addStmt(C);
4191  if (badCFG)
4192  return nullptr;
4193  assert(BeginConditionBlock == ConditionBlock &&
4194  "condition block in for-range was unexpectedly complex");
4195  (void)BeginConditionBlock;
4196  }
4197 
4198  // The condition block is the implicit successor for the loop body as well as
4199  // any code above the loop.
4200  Succ = ConditionBlock;
4201 
4202  // See if this is a known constant.
4203  TryResult KnownVal(true);
4204 
4205  if (S->getCond())
4206  KnownVal = tryEvaluateBool(S->getCond());
4207 
4208  // Now create the loop body.
4209  {
4210  assert(S->getBody());
4211 
4212  // Save the current values for Block, Succ, and continue targets.
4213  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
4214  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
4215 
4216  // Generate increment code in its own basic block. This is the target of
4217  // continue statements.
4218  Block = nullptr;
4219  Succ = addStmt(S->getInc());
4220  if (badCFG)
4221  return nullptr;
4222  ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
4223 
4224  // The starting block for the loop increment is the block that should
4225  // represent the 'loop target' for looping back to the start of the loop.
4226  ContinueJumpTarget.block->setLoopTarget(S);
4227 
4228  // Finish up the increment block and prepare to start the loop body.
4229  assert(Block);
4230  if (badCFG)
4231  return nullptr;
4232  Block = nullptr;
4233 
4234  // Add implicit scope and dtors for loop variable.
4235  addLocalScopeAndDtors(S->getLoopVarStmt());
4236 
4237  // Populate a new block to contain the loop body and loop variable.
4238  addStmt(S->getBody());
4239  if (badCFG)
4240  return nullptr;
4241  CFGBlock *LoopVarStmtBlock = addStmt(S->getLoopVarStmt());
4242  if (badCFG)
4243  return nullptr;
4244 
4245  // This new body block is a successor to our condition block.
4246  addSuccessor(ConditionBlock,
4247  KnownVal.isFalse() ? nullptr : LoopVarStmtBlock);
4248  }
4249 
4250  // Link up the condition block with the code that follows the loop (the
4251  // false branch).
4252  addSuccessor(ConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
4253 
4254  // Add the initialization statements.
4255  Block = createBlock();
4256  addStmt(S->getBeginStmt());
4257  addStmt(S->getEndStmt());
4258  return addStmt(S->getRangeStmt());
4259 }
4260 
4261 CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E,
4262  AddStmtChoice asc) {
4263  if (BuildOpts.AddTemporaryDtors) {
4264  // If adding implicit destructors visit the full expression for adding
4265  // destructors of temporaries.
4266  TempDtorContext Context;
4267  VisitForTemporaryDtors(E->getSubExpr(), false, Context);
4268 
4269  // Full expression has to be added as CFGStmt so it will be sequenced
4270  // before destructors of it's temporaries.
4271  asc = asc.withAlwaysAdd(true);
4272  }
4273  return Visit(E->getSubExpr(), asc);
4274 }
4275 
4276 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
4277  AddStmtChoice asc) {
4278  if (asc.alwaysAdd(*this, E)) {
4279  autoCreateBlock();
4280  appendStmt(Block, E);
4281 
4282  findConstructionContexts(
4283  ConstructionContextLayer::create(cfg->getBumpVectorContext(), E),
4284  E->getSubExpr());
4285 
4286  // We do not want to propagate the AlwaysAdd property.
4287  asc = asc.withAlwaysAdd(false);
4288  }
4289  return Visit(E->getSubExpr(), asc);
4290 }
4291 
4292 CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C,
4293  AddStmtChoice asc) {
4294  // If the constructor takes objects as arguments by value, we need to properly
4295  // construct these objects. Construction contexts we find here aren't for the
4296  // constructor C, they're for its arguments only.
4297  findConstructionContextsForArguments(C);
4298 
4299  autoCreateBlock();
4300  appendConstructor(Block, C);
4301 
4302  return VisitChildren(C);
4303 }
4304 
4305 CFGBlock *CFGBuilder::VisitCXXNewExpr(CXXNewExpr *NE,
4306  AddStmtChoice asc) {
4307  autoCreateBlock();
4308  appendStmt(Block, NE);
4309 
4310  findConstructionContexts(
4311  ConstructionContextLayer::create(cfg->getBumpVectorContext(), NE),
4312  const_cast<CXXConstructExpr *>(NE->getConstructExpr()));
4313 
4314  if (NE->getInitializer())
4315  Block = Visit(NE->getInitializer());
4316 
4317  if (BuildOpts.AddCXXNewAllocator)
4318  appendNewAllocator(Block, NE);
4319 
4320  if (NE->isArray())
4321  Block = Visit(NE->getArraySize());
4322 
4324  E = NE->placement_arg_end(); I != E; ++I)
4325  Block = Visit(*I);
4326 
4327  return Block;
4328 }
4329 
4330 CFGBlock *CFGBuilder::VisitCXXDeleteExpr(CXXDeleteExpr *DE,
4331  AddStmtChoice asc) {
4332  autoCreateBlock();
4333  appendStmt(Block, DE);
4334  QualType DTy = DE->getDestroyedType();
4335  if (!DTy.isNull()) {
4336  DTy = DTy.getNonReferenceType();
4337  CXXRecordDecl *RD = Context->getBaseElementType(DTy)->getAsCXXRecordDecl();
4338  if (RD) {
4339  if (RD->isCompleteDefinition() && !RD->hasTrivialDestructor())
4340  appendDeleteDtor(Block, RD, DE);
4341  }
4342  }
4343 
4344  return VisitChildren(DE);
4345 }
4346 
4347 CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
4348  AddStmtChoice asc) {
4349  if (asc.alwaysAdd(*this, E)) {
4350  autoCreateBlock();
4351  appendStmt(Block, E);
4352  // We do not want to propagate the AlwaysAdd property.
4353  asc = asc.withAlwaysAdd(false);
4354  }
4355  return Visit(E->getSubExpr(), asc);
4356 }
4357 
4358 CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
4359  AddStmtChoice asc) {
4360  // If the constructor takes objects as arguments by value, we need to properly
4361  // construct these objects. Construction contexts we find here aren't for the
4362  // constructor C, they're for its arguments only.
4363  findConstructionContextsForArguments(C);
4364 
4365  autoCreateBlock();
4366  appendConstructor(Block, C);
4367  return VisitChildren(C);
4368 }
4369 
4370 CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E,
4371  AddStmtChoice asc) {
4372  if (asc.alwaysAdd(*this, E)) {
4373  autoCreateBlock();
4374  appendStmt(Block, E);
4375  }
4376  return Visit(E->getSubExpr(), AddStmtChoice());
4377 }
4378 
4379 CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) {
4380  // Lazily create the indirect-goto dispatch block if there isn't one already.
4381  CFGBlock *IBlock = cfg->getIndirectGotoBlock();
4382 
4383  if (!IBlock) {
4384  IBlock = createBlock(false);
4385  cfg->setIndirectGotoBlock(IBlock);
4386  }
4387 
4388  // IndirectGoto is a control-flow statement. Thus we stop processing the
4389  // current block and create a new one.
4390  if (badCFG)
4391  return nullptr;
4392 
4393  Block = createBlock(false);
4394  Block->setTerminator(I);
4395  addSuccessor(Block, IBlock);
4396  return addStmt(I->getTarget());
4397 }
4398 
4399 CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary,
4400  TempDtorContext &Context) {
4401  assert(BuildOpts.AddImplicitDtors && BuildOpts.AddTemporaryDtors);
4402 
4403 tryAgain:
4404  if (!E) {
4405  badCFG = true;
4406  return nullptr;
4407  }
4408  switch (E->getStmtClass()) {
4409  default:
4410  return VisitChildrenForTemporaryDtors(E, Context);
4411 
4412  case Stmt::BinaryOperatorClass:
4413  return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E),
4414  Context);
4415 
4416  case Stmt::CXXBindTemporaryExprClass:
4417  return VisitCXXBindTemporaryExprForTemporaryDtors(
4418  cast<CXXBindTemporaryExpr>(E), BindToTemporary, Context);
4419 
4420  case Stmt::BinaryConditionalOperatorClass:
4421  case Stmt::ConditionalOperatorClass:
4422  return VisitConditionalOperatorForTemporaryDtors(
4423  cast<AbstractConditionalOperator>(E), BindToTemporary, Context);
4424 
4425  case Stmt::ImplicitCastExprClass:
4426  // For implicit cast we want BindToTemporary to be passed further.
4427  E = cast<CastExpr>(E)->getSubExpr();
4428  goto tryAgain;
4429 
4430  case Stmt::CXXFunctionalCastExprClass:
4431  // For functional cast we want BindToTemporary to be passed further.
4432  E = cast<CXXFunctionalCastExpr>(E)->getSubExpr();
4433  goto tryAgain;
4434 
4435  case Stmt::ParenExprClass:
4436  E = cast<ParenExpr>(E)->getSubExpr();
4437  goto tryAgain;
4438 
4439  case Stmt::MaterializeTemporaryExprClass: {
4440  const MaterializeTemporaryExpr* MTE = cast<MaterializeTemporaryExpr>(E);
4441  BindToTemporary = (MTE->getStorageDuration() != SD_FullExpression);
4442  SmallVector<const Expr *, 2> CommaLHSs;
4444  // Find the expression whose lifetime needs to be extended.
4445  E = const_cast<Expr *>(
4446  cast<MaterializeTemporaryExpr>(E)
4447  ->GetTemporaryExpr()
4448  ->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments));
4449  // Visit the skipped comma operator left-hand sides for other temporaries.
4450  for (const Expr *CommaLHS : CommaLHSs) {
4451  VisitForTemporaryDtors(const_cast<Expr *>(CommaLHS),
4452  /*BindToTemporary=*/false, Context);
4453  }
4454  goto tryAgain;
4455  }
4456 
4457  case Stmt::BlockExprClass:
4458  // Don't recurse into blocks; their subexpressions don't get evaluated
4459  // here.
4460  return Block;
4461 
4462  case Stmt::LambdaExprClass: {
4463  // For lambda expressions, only recurse into the capture initializers,
4464  // and not the body.
4465  auto *LE = cast<LambdaExpr>(E);
4466  CFGBlock *B = Block;
4467  for (Expr *Init : LE->capture_inits()) {
4468  if (Init) {
4469  if (CFGBlock *R = VisitForTemporaryDtors(
4470  Init, /*BindToTemporary=*/false, Context))
4471  B = R;
4472  }
4473  }
4474  return B;
4475  }
4476 
4477  case Stmt::CXXDefaultArgExprClass:
4478  E = cast<CXXDefaultArgExpr>(E)->getExpr();
4479  goto tryAgain;
4480 
4481  case Stmt::CXXDefaultInitExprClass:
4482  E = cast<CXXDefaultInitExpr>(E)->getExpr();
4483  goto tryAgain;
4484  }
4485 }
4486 
4487 CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E,
4488  TempDtorContext &Context) {
4489  if (isa<LambdaExpr>(E)) {
4490  // Do not visit the children of lambdas; they have their own CFGs.
4491  return Block;
4492  }
4493 
4494  // When visiting children for destructors we want to visit them in reverse
4495  // order that they will appear in the CFG. Because the CFG is built
4496  // bottom-up, this means we visit them in their natural order, which
4497  // reverses them in the CFG.
4498  CFGBlock *B = Block;
4499  for (Stmt *Child : E->children())
4500  if (Child)
4501  if (CFGBlock *R = VisitForTemporaryDtors(Child, false, Context))
4502  B = R;
4503 
4504  return B;
4505 }
4506 
4507 CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(
4508  BinaryOperator *E, TempDtorContext &Context) {
4509  if (E->isLogicalOp()) {
4510  VisitForTemporaryDtors(E->getLHS(), false, Context);
4511  TryResult RHSExecuted = tryEvaluateBool(E->getLHS());
4512  if (RHSExecuted.isKnown() && E->getOpcode() == BO_LOr)
4513  RHSExecuted.negate();
4514 
4515  // We do not know at CFG-construction time whether the right-hand-side was
4516  // executed, thus we add a branch node that depends on the temporary
4517  // constructor call.
4518  TempDtorContext RHSContext(
4519  bothKnownTrue(Context.KnownExecuted, RHSExecuted));
4520  VisitForTemporaryDtors(E->getRHS(), false, RHSContext);
4521  InsertTempDtorDecisionBlock(RHSContext);
4522 
4523  return Block;
4524  }
4525 
4526  if (E->isAssignmentOp()) {
4527  // For assignment operator (=) LHS expression is visited
4528  // before RHS expression. For destructors visit them in reverse order.
4529  CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
4530  CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
4531  return LHSBlock ? LHSBlock : RHSBlock;
4532  }
4533 
4534  // For any other binary operator RHS expression is visited before
4535  // LHS expression (order of children). For destructors visit them in reverse
4536  // order.
4537  CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
4538  CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
4539  return RHSBlock ? RHSBlock : LHSBlock;
4540 }
4541 
4542 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors(
4543  CXXBindTemporaryExpr *E, bool BindToTemporary, TempDtorContext &Context) {
4544  // First add destructors for temporaries in subexpression.
4545  CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr(), false, Context);
4546  if (!BindToTemporary) {
4547  // If lifetime of temporary is not prolonged (by assigning to constant
4548  // reference) add destructor for it.
4549 
4550  const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor();
4551 
4552  if (Dtor->getParent()->isAnyDestructorNoReturn()) {
4553  // If the destructor is marked as a no-return destructor, we need to
4554  // create a new block for the destructor which does not have as a
4555  // successor anything built thus far. Control won't flow out of this
4556  // block.
4557  if (B) Succ = B;
4558  Block = createNoReturnBlock();
4559  } else if (Context.needsTempDtorBranch()) {
4560  // If we need to introduce a branch, we add a new block that we will hook
4561  // up to a decision block later.
4562  if (B) Succ = B;
4563  Block = createBlock();
4564  } else {
4565  autoCreateBlock();
4566  }
4567  if (Context.needsTempDtorBranch()) {
4568  Context.setDecisionPoint(Succ, E);
4569  }
4570  appendTemporaryDtor(Block, E);
4571 
4572  B = Block;
4573  }
4574  return B;
4575 }
4576 
4577 void CFGBuilder::InsertTempDtorDecisionBlock(const TempDtorContext &Context,
4578  CFGBlock *FalseSucc) {
4579  if (!Context.TerminatorExpr) {
4580  // If no temporary was found, we do not need to insert a decision point.
4581  return;
4582  }
4583  assert(Context.TerminatorExpr);
4584  CFGBlock *Decision = createBlock(false);
4585  Decision->setTerminator(CFGTerminator(Context.TerminatorExpr, true));
4586  addSuccessor(Decision, Block, !Context.KnownExecuted.isFalse());
4587  addSuccessor(Decision, FalseSucc ? FalseSucc : Context.Succ,
4588  !Context.KnownExecuted.isTrue());
4589  Block = Decision;
4590 }
4591 
4592 CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors(
4593  AbstractConditionalOperator *E, bool BindToTemporary,
4594  TempDtorContext &Context) {
4595  VisitForTemporaryDtors(E->getCond(), false, Context);
4596  CFGBlock *ConditionBlock = Block;
4597  CFGBlock *ConditionSucc = Succ;
4598  TryResult ConditionVal = tryEvaluateBool(E->getCond());
4599  TryResult NegatedVal = ConditionVal;
4600  if (NegatedVal.isKnown()) NegatedVal.negate();
4601 
4602  TempDtorContext TrueContext(
4603  bothKnownTrue(Context.KnownExecuted, ConditionVal));
4604  VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary, TrueContext);
4605  CFGBlock *TrueBlock = Block;
4606 
4607  Block = ConditionBlock;
4608  Succ = ConditionSucc;
4609  TempDtorContext FalseContext(
4610  bothKnownTrue(Context.KnownExecuted, NegatedVal));
4611  VisitForTemporaryDtors(E->getFalseExpr(), BindToTemporary, FalseContext);
4612 
4613  if (TrueContext.TerminatorExpr && FalseContext.TerminatorExpr) {
4614  InsertTempDtorDecisionBlock(FalseContext, TrueBlock);
4615  } else if (TrueContext.TerminatorExpr) {
4616  Block = TrueBlock;
4617  InsertTempDtorDecisionBlock(TrueContext);
4618  } else {
4619  InsertTempDtorDecisionBlock(FalseContext);
4620  }
4621  return Block;
4622 }
4623 
4624 /// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has
4625 /// no successors or predecessors. If this is the first block created in the
4626 /// CFG, it is automatically set to be the Entry and Exit of the CFG.
4628  bool first_block = begin() == end();
4629 
4630  // Create the block.
4631  CFGBlock *Mem = getAllocator().Allocate<CFGBlock>();
4632  new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this);
4633  Blocks.push_back(Mem, BlkBVC);
4634 
4635  // If this is the first block, set it as the Entry and Exit.
4636  if (first_block)
4637  Entry = Exit = &back();
4638 
4639  // Return the block.
4640  return &back();
4641 }
4642 
4643 /// buildCFG - Constructs a CFG from an AST.
4644 std::unique_ptr<CFG> CFG::buildCFG(const Decl *D, Stmt *Statement,
4645  ASTContext *C, const BuildOptions &BO) {
4646  CFGBuilder Builder(C, BO);
4647  return Builder.buildCFG(D, Statement);
4648 }
4649 
4650 const CXXDestructorDecl *
4652  switch (getKind()) {
4655  case CFGElement::LoopExit:
4657  case CFGElement::Statement:
4661  case CFGElement::ScopeEnd:
4662  llvm_unreachable("getDestructorDecl should only be used with "
4663  "ImplicitDtors");
4665  const VarDecl *var = castAs<CFGAutomaticObjDtor>().getVarDecl();
4666  QualType ty = var->getType();
4667 
4668  // FIXME: See CFGBuilder::addLocalScopeForVarDecl.
4669  //
4670  // Lifetime-extending constructs are handled here. This works for a single
4671  // temporary in an initializer expression.
4672  if (ty->isReferenceType()) {
4673  if (const Expr *Init = var->getInit()) {
4674  ty = getReferenceInitTemporaryType(Init);
4675  }
4676  }
4677 
4678  while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) {
4679  ty = arrayType->getElementType();
4680  }
4681  const RecordType *recordType = ty->getAs<RecordType>();
4682  const CXXRecordDecl *classDecl =
4683  cast<CXXRecordDecl>(recordType->getDecl());
4684  return classDecl->getDestructor();
4685  }
4686  case CFGElement::DeleteDtor: {
4687  const CXXDeleteExpr *DE = castAs<CFGDeleteDtor>().getDeleteExpr();
4688  QualType DTy = DE->getDestroyedType();
4689  DTy = DTy.getNonReferenceType();
4690  const CXXRecordDecl *classDecl =
4691  astContext.getBaseElementType(DTy)->getAsCXXRecordDecl();
4692  return classDecl->getDestructor();
4693  }
4695  const CXXBindTemporaryExpr *bindExpr =
4696  castAs<CFGTemporaryDtor>().getBindTemporaryExpr();
4697  const CXXTemporary *temp = bindExpr->getTemporary();
4698  return temp->getDestructor();
4699  }
4700  case CFGElement::BaseDtor:
4702  // Not yet supported.
4703  return nullptr;
4704  }
4705  llvm_unreachable("getKind() returned bogus value");
4706 }
4707 
4708 bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const {
4709  if (const CXXDestructorDecl *DD = getDestructorDecl(astContext))
4710  return DD->isNoReturn();
4711  return false;
4712 }
4713 
4714 //===----------------------------------------------------------------------===//
4715 // CFGBlock operations.
4716 //===----------------------------------------------------------------------===//
4717 
4719  : ReachableBlock(IsReachable ? B : nullptr),
4720  UnreachableBlock(!IsReachable ? B : nullptr,
4721  B && IsReachable ? AB_Normal : AB_Unreachable) {}
4722 
4724  : ReachableBlock(B),
4725  UnreachableBlock(B == AlternateBlock ? nullptr : AlternateBlock,
4726  B == AlternateBlock ? AB_Alternate : AB_Normal) {}
4727 
4729  BumpVectorContext &C) {
4730  if (CFGBlock *B = Succ.getReachableBlock())
4731  B->Preds.push_back(AdjacentBlock(this, Succ.isReachable()), C);
4732 
4733  if (CFGBlock *UnreachableB = Succ.getPossiblyUnreachableBlock())
4734  UnreachableB->Preds.push_back(AdjacentBlock(this, false), C);
4735 
4736  Succs.push_back(Succ, C);
4737 }
4738 
4740  const CFGBlock *From, const CFGBlock *To) {
4741  if (F.IgnoreNullPredecessors && !From)
4742  return true;
4743 
4744  if (To && From && F.IgnoreDefaultsWithCoveredEnums) {
4745  // If the 'To' has no label or is labeled but the label isn't a
4746  // CaseStmt then filter this edge.
4747  if (const SwitchStmt *S =
4748  dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) {
4749  if (S->isAllEnumCasesCovered()) {
4750  const Stmt *L = To->getLabel();
4751  if (!L || !isa<CaseStmt>(L))
4752  return true;
4753  }
4754  }
4755  }
4756 
4757  return false;
4758 }
4759 
4760 //===----------------------------------------------------------------------===//
4761 // CFG pretty printing
4762 //===----------------------------------------------------------------------===//
4763 
4764 namespace {
4765 
4766 class StmtPrinterHelper : public PrinterHelper {
4767  using StmtMapTy = llvm::DenseMap<const Stmt *, std::pair<unsigned, unsigned>>;
4768  using DeclMapTy = llvm::DenseMap<const Decl *, std::pair<unsigned, unsigned>>;
4769 
4770  StmtMapTy StmtMap;
4771  DeclMapTy DeclMap;
4772  signed currentBlock = 0;
4773  unsigned currStmt = 0;
4774  const LangOptions &LangOpts;
4775 
4776 public:
4777  StmtPrinterHelper(const CFG* cfg, const LangOptions &LO)
4778  : LangOpts(LO) {
4779  for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) {
4780  unsigned j = 1;
4781  for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ;
4782  BI != BEnd; ++BI, ++j ) {
4783  if (Optional<CFGStmt> SE = BI->getAs<CFGStmt>()) {
4784  const Stmt *stmt= SE->getStmt();
4785  std::pair<unsigned, unsigned> P((*I)->getBlockID(), j);
4786  StmtMap[stmt] = P;
4787 
4788  switch (stmt->getStmtClass()) {
4789  case Stmt::DeclStmtClass:
4790  DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P;
4791  break;
4792  case Stmt::IfStmtClass: {
4793  const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable();
4794  if (var)
4795  DeclMap[var] = P;
4796  break;
4797  }
4798  case Stmt::ForStmtClass: {
4799  const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable();
4800  if (var)
4801  DeclMap[var] = P;
4802  break;
4803  }
4804  case Stmt::WhileStmtClass: {
4805  const VarDecl *var =
4806  cast<WhileStmt>(stmt)->getConditionVariable();
4807  if (var)
4808  DeclMap[var] = P;
4809  break;
4810  }
4811  case Stmt::SwitchStmtClass: {
4812  const VarDecl *var =
4813  cast<SwitchStmt>(stmt)->getConditionVariable();
4814  if (var)
4815  DeclMap[var] = P;
4816  break;
4817  }
4818  case Stmt::CXXCatchStmtClass: {
4819  const VarDecl *var =
4820  cast<CXXCatchStmt>(stmt)->getExceptionDecl();
4821  if (var)
4822  DeclMap[var] = P;
4823  break;
4824  }
4825  default:
4826  break;
4827  }
4828  }
4829  }
4830  }
4831  }
4832 
4833  ~StmtPrinterHelper() override = default;
4834 
4835  const LangOptions &getLangOpts() const { return LangOpts; }
4836  void setBlockID(signed i) { currentBlock = i; }
4837  void setStmtID(unsigned i) { currStmt = i; }
4838 
4839  bool handledStmt(Stmt *S, raw_ostream &OS) override {
4840  StmtMapTy::iterator I = StmtMap.find(S);
4841 
4842  if (I == StmtMap.end())
4843  return false;
4844 
4845  if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
4846  && I->second.second == currStmt) {
4847  return false;
4848  }
4849 
4850  OS << "[B" << I->second.first << "." << I->second.second << "]";
4851  return true;
4852  }
4853 
4854  bool handleDecl(const Decl *D, raw_ostream &OS) {
4855  DeclMapTy::iterator I = DeclMap.find(D);
4856 
4857  if (I == DeclMap.end())
4858  return false;
4859 
4860  if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
4861  && I->second.second == currStmt) {
4862  return false;
4863  }
4864 
4865  OS << "[B" << I->second.first << "." << I->second.second << "]";
4866  return true;
4867  }
4868 };
4869 
4870 class CFGBlockTerminatorPrint
4871  : public StmtVisitor<CFGBlockTerminatorPrint,void> {
4872  raw_ostream &OS;
4873  StmtPrinterHelper* Helper;
4874  PrintingPolicy Policy;
4875 
4876 public:
4877  CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper,
4878  const PrintingPolicy &Policy)
4879  : OS(os), Helper(helper), Policy(Policy) {
4880  this->Policy.IncludeNewlines = false;
4881  }
4882 
4883  void VisitIfStmt(IfStmt *I) {
4884  OS << "if ";
4885  if (Stmt *C = I->getCond())
4886  C->printPretty(OS, Helper, Policy);
4887  }
4888 
4889  // Default case.
4890  void VisitStmt(Stmt *Terminator) {
4891  Terminator->printPretty(OS, Helper, Policy);
4892  }
4893 
4894  void VisitDeclStmt(DeclStmt *DS) {
4895  VarDecl *VD = cast<VarDecl>(DS->getSingleDecl());
4896  OS << "static init " << VD->getName();
4897  }
4898 
4899  void VisitForStmt(ForStmt *F) {
4900  OS << "for (" ;
4901  if (F->getInit())
4902  OS << "...";
4903  OS << "; ";
4904  if (Stmt *C = F->getCond())
4905  C->printPretty(OS, Helper, Policy);
4906  OS << "; ";
4907  if (F->getInc())
4908  OS << "...";
4909  OS << ")";
4910  }
4911 
4912  void VisitWhileStmt(WhileStmt *W) {
4913  OS << "while " ;
4914  if (Stmt *C = W->getCond())
4915  C->printPretty(OS, Helper, Policy);
4916  }
4917 
4918  void VisitDoStmt(DoStmt *D) {
4919  OS << "do ... while ";
4920  if (Stmt *C = D->getCond())
4921  C->printPretty(OS, Helper, Policy);
4922  }
4923 
4924  void VisitSwitchStmt(SwitchStmt *Terminator) {
4925  OS << "switch ";
4926  Terminator->getCond()->printPretty(OS, Helper, Policy);
4927  }
4928 
4929  void VisitCXXTryStmt(CXXTryStmt *CS) {
4930  OS << "try ...";
4931  }
4932 
4933  void VisitSEHTryStmt(SEHTryStmt *CS) {
4934  OS << "__try ...";
4935  }
4936 
4937  void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) {
4938  if (Stmt *Cond = C->getCond())
4939  Cond->printPretty(OS, Helper, Policy);
4940  OS << " ? ... : ...";
4941  }
4942 
4943  void VisitChooseExpr(ChooseExpr *C) {
4944  OS << "__builtin_choose_expr( ";
4945  if (Stmt *Cond = C->getCond())
4946  Cond->printPretty(OS, Helper, Policy);
4947  OS << " )";
4948  }
4949 
4950  void VisitIndirectGotoStmt(IndirectGotoStmt *I) {
4951  OS << "goto *";
4952  if (Stmt *T = I->getTarget())
4953  T->printPretty(OS, Helper, Policy);
4954  }
4955 
4956  void VisitBinaryOperator(BinaryOperator* B) {
4957  if (!B->isLogicalOp()) {
4958  VisitExpr(B);
4959  return;
4960  }
4961 
4962  if (B->getLHS())
4963  B->getLHS()->printPretty(OS, Helper, Policy);
4964 
4965  switch (B->getOpcode()) {
4966  case BO_LOr:
4967  OS << " || ...";
4968  return;
4969  case BO_LAnd:
4970  OS << " && ...";
4971  return;
4972  default:
4973  llvm_unreachable("Invalid logical operator.");
4974  }
4975  }
4976 
4977  void VisitExpr(Expr *E) {
4978  E->printPretty(OS, Helper, Policy);
4979  }
4980 
4981 public:
4982  void print(CFGTerminator T) {
4983  if (T.isTemporaryDtorsBranch())
4984  OS << "(Temp Dtor) ";
4985  Visit(T.getStmt());
4986  }
4987 };
4988 
4989 } // namespace
4990 
4991 static void print_initializer(raw_ostream &OS, StmtPrinterHelper &Helper,
4992  const CXXCtorInitializer *I) {
4993  if (I->isBaseInitializer())
4994  OS << I->getBaseClass()->getAsCXXRecordDecl()->getName();
4995  else if (I->isDelegatingInitializer())
4997  else
4998  OS << I->getAnyMember()->getName();
4999  OS << "(";
5000  if (Expr *IE = I->getInit())
5001  IE->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
5002  OS << ")";
5003 
5004  if (I->isBaseInitializer())
5005  OS << " (Base initializer)";
5006  else if (I->isDelegatingInitializer())
5007  OS << " (Delegating initializer)";
5008  else
5009  OS << " (Member initializer)";
5010 }
5011 
5012 static void print_construction_context(raw_ostream &OS,
5013  StmtPrinterHelper &Helper,
5014  const ConstructionContext *CC) {
5016  switch (CC->getKind()) {
5018  OS << ", ";
5019  const auto *SICC = cast<SimpleConstructorInitializerConstructionContext>(CC);
5020  print_initializer(OS, Helper, SICC->getCXXCtorInitializer());
5021  return;
5022  }
5024  OS << ", ";
5025  const auto *CICC =
5026  cast<CXX17ElidedCopyConstructorInitializerConstructionContext>(CC);
5027  print_initializer(OS, Helper, CICC->getCXXCtorInitializer());
5028  Stmts.push_back(CICC->getCXXBindTemporaryExpr());
5029  break;
5030  }
5032  const auto *SDSCC = cast<SimpleVariableConstructionContext>(CC);
5033  Stmts.push_back(SDSCC->getDeclStmt());
5034  break;
5035  }
5037  const auto *CDSCC = cast<CXX17ElidedCopyVariableConstructionContext>(CC);
5038  Stmts.push_back(CDSCC->getDeclStmt());
5039  Stmts.push_back(CDSCC->getCXXBindTemporaryExpr());
5040  break;
5041  }
5043  const auto *NECC = cast<NewAllocatedObjectConstructionContext>(CC);
5044  Stmts.push_back(NECC->getCXXNewExpr());
5045  break;
5046  }
5048  const auto *RSCC = cast<SimpleReturnedValueConstructionContext>(CC);
5049  Stmts.push_back(RSCC->getReturnStmt());
5050  break;
5051  }
5053  const auto *RSCC =
5054  cast<CXX17ElidedCopyReturnedValueConstructionContext>(CC);
5055  Stmts.push_back(RSCC->getReturnStmt());
5056  Stmts.push_back(RSCC->getCXXBindTemporaryExpr());
5057  break;
5058  }
5060  const auto *TOCC = cast<SimpleTemporaryObjectConstructionContext>(CC);
5061  Stmts.push_back(TOCC->getCXXBindTemporaryExpr());
5062  Stmts.push_back(TOCC->getMaterializedTemporaryExpr());
5063  break;
5064  }
5066  const auto *TOCC = cast<ElidedTemporaryObjectConstructionContext>(CC);
5067  Stmts.push_back(TOCC->getCXXBindTemporaryExpr());
5068  Stmts.push_back(TOCC->getMaterializedTemporaryExpr());
5069  Stmts.push_back(TOCC->getConstructorAfterElision());
5070  break;
5071  }
5073  const auto *ACC = cast<ArgumentConstructionContext>(CC);
5074  if (const Stmt *BTE = ACC->getCXXBindTemporaryExpr()) {
5075  OS << ", ";
5076  Helper.handledStmt(const_cast<Stmt *>(BTE), OS);
5077  }
5078  OS << ", ";
5079  Helper.handledStmt(const_cast<Expr *>(ACC->getCallLikeExpr()), OS);
5080  OS << "+" << ACC->getIndex();
5081  return;
5082  }
5083  }
5084  for (auto I: Stmts)
5085  if (I) {
5086  OS << ", ";
5087  Helper.handledStmt(const_cast<Stmt *>(I), OS);
5088  }
5089 }
5090 
5091 static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
5092  const CFGElement &E) {
5093  if (Optional<CFGStmt> CS = E.getAs<CFGStmt>()) {
5094  const Stmt *S = CS->getStmt();
5095  assert(S != nullptr && "Expecting non-null Stmt");
5096 
5097  // special printing for statement-expressions.
5098  if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) {
5099  const CompoundStmt *Sub = SE->getSubStmt();
5100 
5101  auto Children = Sub->children();
5102  if (Children.begin() != Children.end()) {
5103  OS << "({ ... ; ";
5104  Helper.handledStmt(*SE->getSubStmt()->body_rbegin(),OS);
5105  OS << " })\n";
5106  return;
5107  }
5108  }
5109  // special printing for comma expressions.
5110  if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) {
5111  if (B->getOpcode() == BO_Comma) {
5112  OS << "... , ";
5113  Helper.handledStmt(B->getRHS(),OS);
5114  OS << '\n';
5115  return;
5116  }
5117  }
5118  S->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
5119 
5120  if (auto VTC = E.getAs<CFGCXXRecordTypedCall>()) {
5121  if (isa<CXXOperatorCallExpr>(S))
5122  OS << " (OperatorCall)";
5123  OS << " (CXXRecordTypedCall";
5124  print_construction_context(OS, Helper, VTC->getConstructionContext());
5125  OS << ")";
5126  } else if (isa<CXXOperatorCallExpr>(S)) {
5127  OS << " (OperatorCall)";
5128  } else if (isa<CXXBindTemporaryExpr>(S)) {
5129  OS << " (BindTemporary)";
5130  } else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) {
5131  OS << " (CXXConstructExpr";
5133  print_construction_context(OS, Helper, CE->getConstructionContext());
5134  }
5135  OS << ", " << CCE->getType().getAsString() << ")";
5136  } else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) {
5137  OS << " (" << CE->getStmtClassName() << ", "
5138  << CE->getCastKindName()
5139  << ", " << CE->getType().getAsString()
5140  << ")";
5141  }
5142 
5143  // Expressions need a newline.
5144  if (isa<Expr>(S))
5145  OS << '\n';
5146  } else if (Optional<CFGInitializer> IE = E.getAs<CFGInitializer>()) {
5147  print_initializer(OS, Helper, IE->getInitializer());
5148  OS << '\n';
5149  } else if (Optional<CFGAutomaticObjDtor> DE =
5150  E.getAs<CFGAutomaticObjDtor>()) {
5151  const VarDecl *VD = DE->getVarDecl();
5152  Helper.handleDecl(VD, OS);
5153 
5154  ASTContext &ACtx = VD->getASTContext();
5155  QualType T = VD->getType();
5156  if (T->isReferenceType())
5157  T = getReferenceInitTemporaryType(VD->getInit(), nullptr);
5158  if (const ArrayType *AT = ACtx.getAsArrayType(T))
5159  T = ACtx.getBaseElementType(AT);
5160 
5161  OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()";
5162  OS << " (Implicit destructor)\n";
5163  } else if (Optional<CFGLifetimeEnds> DE = E.getAs<CFGLifetimeEnds>()) {
5164  const VarDecl *VD = DE->getVarDecl();
5165  Helper.handleDecl(VD, OS);
5166 
5167  OS << " (Lifetime ends)\n";
5168  } else if (Optional<CFGLoopExit> LE = E.getAs<CFGLoopExit>()) {
5169  const Stmt *LoopStmt = LE->getLoopStmt();
5170  OS << LoopStmt->getStmtClassName() << " (LoopExit)\n";
5171  } else if (Optional<CFGScopeBegin> SB = E.getAs<CFGScopeBegin>()) {
5172  OS << "CFGScopeBegin(";
5173  if (const VarDecl *VD = SB->getVarDecl())
5174  OS << VD->getQualifiedNameAsString();
5175  OS << ")\n";
5176  } else if (Optional<CFGScopeEnd> SE = E.getAs<CFGScopeEnd>()) {
5177  OS << "CFGScopeEnd(";
5178  if (const VarDecl *VD = SE->getVarDecl())
5179  OS << VD->getQualifiedNameAsString();
5180  OS << ")\n";
5181  } else if (Optional<CFGNewAllocator> NE = E.getAs<CFGNewAllocator>()) {
5182  OS << "CFGNewAllocator(";
5183  if (const CXXNewExpr *AllocExpr = NE->getAllocatorExpr())
5184  AllocExpr->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
5185  OS << ")\n";
5186  } else if (Optional<CFGDeleteDtor> DE = E.getAs<CFGDeleteDtor>()) {
5187  const CXXRecordDecl *RD = DE->getCXXRecordDecl();
5188  if (!RD)
5189  return;
5190  CXXDeleteExpr *DelExpr =
5191  const_cast<CXXDeleteExpr*>(DE->getDeleteExpr());
5192  Helper.handledStmt(cast<Stmt>(DelExpr->getArgument()), OS);
5193  OS << "->~" << RD->getName().str() << "()";
5194  OS << " (Implicit destructor)\n";
5195  } else if (Optional<CFGBaseDtor> BE = E.getAs<CFGBaseDtor>()) {
5196  const CXXBaseSpecifier *BS = BE->getBaseSpecifier();
5197  OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()";
5198  OS << " (Base object destructor)\n";
5199  } else if (Optional<CFGMemberDtor> ME = E.getAs<CFGMemberDtor>()) {
5200  const FieldDecl *FD = ME->getFieldDecl();
5201  const Type *T = FD->getType()->getBaseElementTypeUnsafe();
5202  OS << "this->" << FD->getName();
5203  OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()";
5204  OS << " (Member object destructor)\n";
5205  } else if (Optional<CFGTemporaryDtor> TE = E.getAs<CFGTemporaryDtor>()) {
5206  const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr();
5207  OS << "~";
5208  BT->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
5209  OS << "() (Temporary object destructor)\n";
5210  }
5211 }
5212 
5213 static void print_block(raw_ostream &OS, const CFG* cfg,
5214  const CFGBlock &B,
5215  StmtPrinterHelper &Helper, bool print_edges,
5216  bool ShowColors) {
5217  Helper.setBlockID(B.getBlockID());
5218 
5219  // Print the header.
5220  if (ShowColors)
5221  OS.changeColor(raw_ostream::YELLOW, true);
5222 
5223  OS << "\n [B" << B.getBlockID();
5224 
5225  if (&B == &cfg->getEntry())
5226  OS << " (ENTRY)]\n";
5227  else if (&B == &cfg->getExit())
5228  OS << " (EXIT)]\n";
5229  else if (&B == cfg->getIndirectGotoBlock())
5230  OS << " (INDIRECT GOTO DISPATCH)]\n";
5231  else if (B.hasNoReturnElement())
5232  OS << " (NORETURN)]\n";
5233  else
5234  OS << "]\n";
5235 
5236  if (ShowColors)
5237  OS.resetColor();
5238 
5239  // Print the label of this block.
5240  if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) {
5241  if (print_edges)
5242  OS << " ";
5243 
5244  if (LabelStmt *L = dyn_cast<LabelStmt>(Label))
5245  OS << L->getName();
5246  else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) {
5247  OS << "case ";
5248  if (C->getLHS())
5249  C->getLHS()->printPretty(OS, &Helper,
5250  PrintingPolicy(Helper.getLangOpts()));
5251  if (C->getRHS()) {
5252  OS << " ... ";
5253  C->getRHS()->printPretty(OS, &Helper,
5254  PrintingPolicy(Helper.getLangOpts()));
5255  }
5256  } else if (isa<DefaultStmt>(Label))
5257  OS << "default";
5258  else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) {
5259  OS << "catch (";
5260  if (CS->getExceptionDecl())
5261  CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper.getLangOpts()),
5262  0);
5263  else
5264  OS << "...";
5265  OS << ")";
5266  } else if (SEHExceptStmt *ES = dyn_cast<SEHExceptStmt>(Label)) {
5267  OS << "__except (";
5268  ES->getFilterExpr()->printPretty(OS, &Helper,
5269  PrintingPolicy(Helper.getLangOpts()), 0);
5270  OS << ")";
5271  } else
5272  llvm_unreachable("Invalid label statement in CFGBlock.");
5273 
5274  OS << ":\n";
5275  }
5276 
5277  // Iterate through the statements in the block and print them.
5278  unsigned j = 1;
5279 
5280  for (CFGBlock::const_iterator I = B.begin(), E = B.end() ;
5281  I != E ; ++I, ++j ) {
5282  // Print the statement # in the basic block and the statement itself.
5283  if (print_edges)
5284  OS << " ";
5285 
5286  OS << llvm::format("%3d", j) << ": ";
5287 
5288  Helper.setStmtID(j);
5289 
5290  print_elem(OS, Helper, *I);
5291  }
5292 
5293  // Print the terminator of this block.
5294  if (B.getTerminator()) {
5295  if (ShowColors)
5296  OS.changeColor(raw_ostream::GREEN);
5297 
5298  OS << " T: ";
5299 
5300  Helper.setBlockID(-1);
5301 
5302  PrintingPolicy PP(Helper.getLangOpts());
5303  CFGBlockTerminatorPrint TPrinter(OS, &Helper, PP);
5304  TPrinter.print(B.getTerminator());
5305  OS << '\n';
5306 
5307  if (ShowColors)
5308  OS.resetColor();
5309  }
5310 
5311  if (print_edges) {
5312  // Print the predecessors of this block.
5313  if (!B.pred_empty()) {
5314  const raw_ostream::Colors Color = raw_ostream::BLUE;
5315  if (ShowColors)
5316  OS.changeColor(Color);
5317  OS << " Preds " ;
5318  if (ShowColors)
5319  OS.resetColor();
5320  OS << '(' << B.pred_size() << "):";
5321  unsigned i = 0;
5322 
5323  if (ShowColors)
5324  OS.changeColor(Color);
5325 
5326  for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end();
5327  I != E; ++I, ++i) {
5328  if (i % 10 == 8)
5329  OS << "\n ";
5330 
5331  CFGBlock *B = *I;
5332  bool Reachable = true;
5333  if (!B) {
5334  Reachable = false;
5335  B = I->getPossiblyUnreachableBlock();
5336  }
5337 
5338  OS << " B" << B->getBlockID();
5339  if (!Reachable)
5340  OS << "(Unreachable)";
5341  }
5342 
5343  if (ShowColors)
5344  OS.resetColor();
5345 
5346  OS << '\n';
5347  }
5348 
5349  // Print the successors of this block.
5350  if (!B.succ_empty()) {
5351  const raw_ostream::Colors Color = raw_ostream::MAGENTA;
5352  if (ShowColors)
5353  OS.changeColor(Color);
5354  OS << " Succs ";
5355  if (ShowColors)
5356  OS.resetColor();
5357  OS << '(' << B.succ_size() << "):";
5358  unsigned i = 0;
5359 
5360  if (ShowColors)
5361  OS.changeColor(Color);
5362 
5363  for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end();
5364  I != E; ++I, ++i) {
5365  if (i % 10 == 8)
5366  OS << "\n ";
5367 
5368  CFGBlock *B = *I;
5369 
5370  bool Reachable = true;
5371  if (!B) {
5372  Reachable = false;
5373  B = I->getPossiblyUnreachableBlock();
5374  }
5375 
5376  if (B) {
5377  OS << " B" << B->getBlockID();
5378  if (!Reachable)
5379  OS << "(Unreachable)";
5380  }
5381  else {
5382  OS << " NULL";
5383  }
5384  }
5385 
5386  if (ShowColors)
5387  OS.resetColor();
5388  OS << '\n';
5389  }
5390  }
5391 }
5392 
5393 /// dump - A simple pretty printer of a CFG that outputs to stderr.
5394 void CFG::dump(const LangOptions &LO, bool ShowColors) const {
5395  print(llvm::errs(), LO, ShowColors);
5396 }
5397 
5398 /// print - A simple pretty printer of a CFG that outputs to an ostream.
5399 void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const {
5400  StmtPrinterHelper Helper(this, LO);
5401 
5402  // Print the entry block.
5403  print_block(OS, this, getEntry(), Helper, true, ShowColors);
5404 
5405  // Iterate through the CFGBlocks and print them one by one.
5406  for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) {
5407  // Skip the entry block, because we already printed it.
5408  if (&(**I) == &getEntry() || &(**I) == &getExit())
5409  continue;
5410 
5411  print_block(OS, this, **I, Helper, true, ShowColors);
5412  }
5413 
5414  // Print the exit block.
5415  print_block(OS, this, getExit(), Helper, true, ShowColors);
5416  OS << '\n';
5417  OS.flush();
5418 }
5419 
5420 /// dump - A simply pretty printer of a CFGBlock that outputs to stderr.
5421 void CFGBlock::dump(const CFG* cfg, const LangOptions &LO,
5422  bool ShowColors) const {
5423  print(llvm::errs(), cfg, LO, ShowColors);
5424 }
5425 
5426 LLVM_DUMP_METHOD void CFGBlock::dump() const {
5427  dump(getParent(), LangOptions(), false);
5428 }
5429 
5430 /// print - A simple pretty printer of a CFGBlock that outputs to an ostream.
5431 /// Generally this will only be called from CFG::print.
5432 void CFGBlock::print(raw_ostream &OS, const CFG* cfg,
5433  const LangOptions &LO, bool ShowColors) const {
5434  StmtPrinterHelper Helper(cfg, LO);
5435  print_block(OS, cfg, *this, Helper, true, ShowColors);
5436  OS << '\n';
5437 }
5438 
5439 /// printTerminator - A simple pretty printer of the terminator of a CFGBlock.
5440 void CFGBlock::printTerminator(raw_ostream &OS,
5441  const LangOptions &LO) const {
5442  CFGBlockTerminatorPrint TPrinter(OS, nullptr, PrintingPolicy(LO));
5443  TPrinter.print(getTerminator());
5444 }
5445 
5447  Stmt *Terminator = this->Terminator;
5448  if (!Terminator)
5449  return nullptr;
5450 
5451  Expr *E = nullptr;
5452 
5453  switch (Terminator->getStmtClass()) {
5454  default:
5455  break;
5456 
5457  case Stmt::CXXForRangeStmtClass:
5458  E = cast<CXXForRangeStmt>(Terminator)->getCond();
5459  break;
5460 
5461  case Stmt::ForStmtClass:
5462  E = cast<ForStmt>(Terminator)->getCond();
5463  break;
5464 
5465  case Stmt::WhileStmtClass:
5466  E = cast<WhileStmt>(Terminator)->getCond();
5467  break;
5468 
5469  case Stmt::DoStmtClass:
5470  E = cast<DoStmt>(Terminator)->getCond();
5471  break;
5472 
5473  case Stmt::IfStmtClass:
5474  E = cast<IfStmt>(Terminator)->getCond();
5475  break;
5476 
5477  case Stmt::ChooseExprClass:
5478  E = cast<ChooseExpr>(Terminator)->getCond();
5479  break;
5480 
5481  case Stmt::IndirectGotoStmtClass:
5482  E = cast<IndirectGotoStmt>(Terminator)->getTarget();
5483  break;
5484 
5485  case Stmt::SwitchStmtClass:
5486  E = cast<SwitchStmt>(Terminator)->getCond();
5487  break;
5488 
5489  case Stmt::BinaryConditionalOperatorClass:
5490  E = cast<BinaryConditionalOperator>(Terminator)->getCond();
5491  break;
5492 
5493  case Stmt::ConditionalOperatorClass:
5494  E = cast<ConditionalOperator>(Terminator)->getCond();
5495  break;
5496 
5497  case Stmt::BinaryOperatorClass: // '&&' and '||'
5498  E = cast<BinaryOperator>(Terminator)->getLHS();
5499  break;
5500 
5501  case Stmt::ObjCForCollectionStmtClass:
5502  return Terminator;
5503  }
5504 
5505  if (!StripParens)
5506  return E;
5507 
5508  return E ? E->IgnoreParens() : nullptr;
5509 }
5510 
5511 //===----------------------------------------------------------------------===//
5512 // CFG Graphviz Visualization
5513 //===----------------------------------------------------------------------===//
5514 
5515 #ifndef NDEBUG
5516 static StmtPrinterHelper* GraphHelper;
5517 #endif
5518 
5519 void CFG::viewCFG(const LangOptions &LO) const {
5520 #ifndef NDEBUG
5521  StmtPrinterHelper H(this, LO);
5522  GraphHelper = &H;
5523  llvm::ViewGraph(this,"CFG");
5524  GraphHelper = nullptr;
5525 #endif
5526 }
5527 
5528 namespace llvm {
5529 
5530 template<>
5531 struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits {
5532  DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
5533 
5534  static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) {
5535 #ifndef NDEBUG
5536  std::string OutSStr;
5537  llvm::raw_string_ostream Out(OutSStr);
5538  print_block(Out,Graph, *Node, *GraphHelper, false, false);
5539  std::string& OutStr = Out.str();
5540 
5541  if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
5542 
5543  // Process string output to make it nicer...
5544  for (unsigned i = 0; i != OutStr.length(); ++i)
5545  if (OutStr[i] == '\n') { // Left justify
5546  OutStr[i] = '\\';
5547  OutStr.insert(OutStr.begin()+i+1, 'l');
5548  }
5549 
5550  return OutStr;
5551 #else
5552  return {};
5553 #endif
5554  }
5555 };
5556 
5557 } // namespace llvm
Expr * getInc()
Definition: Stmt.h:1268
unsigned getNumSemanticExprs() const
Definition: Expr.h:5160
bool isBaseInitializer() const
Determine whether this initializer is initializing a base class.
Definition: DeclCXX.h:2316
bool isNoReturn() const
Determines whether this function is known to be &#39;noreturn&#39;, through an attribute on its declaration o...
Definition: Decl.cpp:2913
Defines the clang::ASTContext interface.
const BlockDecl * getBlockDecl() const
Definition: Expr.h:4988
Represents C++ allocator call.
Definition: CFG.h:240
const CXXDestructorDecl * getDestructor() const
Definition: ExprCXX.h:1196
Represents a function declaration or definition.
Definition: Decl.h:1717
Expr * getInit() const
Get the initializer.
Definition: DeclCXX.h:2445
const Stmt * getElse() const
Definition: Stmt.h:999
CompoundStmt * getBlock() const
Definition: Stmt.h:1982
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:3841
pred_iterator pred_end()
Definition: CFG.h:734
PointerType - C99 6.7.5.1 - Pointer Declarators.
Definition: Type.h:2511
QualType getPointeeType() const
Definition: Type.h:2524
A (possibly-)qualified type.
Definition: Type.h:642
bool isBlockPointerType() const
Definition: Type.h:6185
base_class_range bases()
Definition: DeclCXX.h:823
Expr * getCond() const
Definition: Expr.h:3832
static SourceLocation GetEndLoc(Decl *D)
Definition: CFG.cpp:66
AdjacentBlocks::const_iterator const_pred_iterator
Definition: CFG.h:720
iterator beginScopeEndInsert(iterator I, size_t Cnt, BumpVectorContext &C)
Definition: CFG.h:973
const internal::VariadicAllOfMatcher< Stmt > stmt
Matches statements.
const Expr * skipRValueSubobjectAdjustments(SmallVectorImpl< const Expr *> &CommaLHS, SmallVectorImpl< SubobjectAdjustment > &Adjustments) const
Walk outwards from an expression we want to bind a reference to and find the expression whose lifetim...
Definition: Expr.cpp:77
void print(raw_ostream &OS, const PrintingPolicy &Policy, const Twine &PlaceHolder=Twine(), unsigned Indentation=0) const
Definition: Type.h:985
bool operator==(CanQual< T > x, CanQual< U > y)
Expr * getCond()
Definition: Stmt.h:1158
DOTGraphTraits(bool isSimple=false)
Definition: CFG.cpp:5532
ElementList::iterator iterator
Definition: CFG.h:695
succ_iterator succ_begin()
Definition: CFG.h:751
CompoundStmt * getSubStmt()
Definition: Expr.h:3627
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:1263
Stmt - This represents one statement.
Definition: Stmt.h:66
FunctionType - C99 6.7.5.3 - Function Declarators.
Definition: Type.h:3329
CXXCatchStmt * getHandler(unsigned i)
Definition: StmtCXX.h:104
CFGBlock & getEntry()
Definition: CFG.h:1093
IfStmt - This represents an if/then/else.
Definition: Stmt.h:959
StorageClass getStorageClass() const
Returns the storage class as written in the source.
Definition: Decl.h:1017
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:2557
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:52
Opcode getOpcode() const
Definition: Expr.h:3143
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:6126
void appendLifetimeEnds(VarDecl *VD, Stmt *S, BumpVectorContext &C)
Definition: CFG.h:932
The base class of the type hierarchy.
Definition: Type.h:1415
Represents Objective-C&#39;s @throw statement.
Definition: StmtObjC.h:313
Represents C++ object destructor generated from a call to delete.
Definition: CFG.h:409
Represents an array type, per C99 6.7.5.2 - Array Declarators.
Definition: Type.h:2786
iterator begin()
Definition: CFG.h:703
Represents a call to a C++ constructor.
Definition: ExprCXX.h:1262
unsigned IgnoreDefaultsWithCoveredEnums
Definition: CFG.h:779
Represents a C++ constructor within a class.
Definition: DeclCXX.h:2475
Represents a prvalue temporary that is written into memory so that a reference can bind to it...
Definition: ExprCXX.h:4077
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:3146
VarDecl * getConditionVariable() const
Retrieve the variable declared in this "while" statement, if any.
Definition: Stmt.cpp:910
unsigned succ_size() const
Definition: CFG.h:769
const CXXDestructorDecl * getDestructorDecl(ASTContext &astContext) const
Definition: CFG.cpp:4651
Stmt * getSubStmt()
Definition: Stmt.h:834
bool isUnsignedIntegerType() const
Return true if this is an integer type that is unsigned, according to C99 6.2.5p6 [which returns true...
Definition: Type.cpp:1876
bool EvaluateAsInt(llvm::APSInt &Result, const ASTContext &Ctx, SideEffectsKind AllowSideEffects=SE_NoSideEffects) const
EvaluateAsInt - Return true if this is a constant which we can fold and convert to an integer...
Represents a variable declaration or definition.
Definition: Decl.h:812
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6590
CFGBlock * getReachableBlock() const
Get the reachable block, if one exists.
Definition: CFG.h:640
const char * getName() const
Definition: Stmt.cpp:342
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:5091
A C++ throw-expression (C++ [except.throw]).
Definition: ExprCXX.h:1006
Represents an expression – generally a full-expression – that introduces cleanups to be run at the ...
Definition: ExprCXX.h:3033
static bool isAssignmentOp(Opcode Opc)
Definition: Expr.h:3225
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:876
const Stmt * getSubStmt() const
Definition: StmtObjC.h:356
const char * getStmtClassName() const
Definition: Stmt.cpp:75
Represents a function call that returns a C++ object by value.
Definition: CFG.h:179
LabelStmt - Represents a label, which has a substatement.
Definition: Stmt.h:864
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:1206
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:2628
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:154
void setLoopTarget(const Stmt *loopTarget)
Definition: CFG.h:837
static std::string getNodeLabel(const CFGBlock *Node, const CFG *Graph)
Definition: CFG.cpp:5534
field_range fields() const
Definition: Decl.h:3761
Represents a member of a struct/union/class.
Definition: Decl.h:2556
TypeSourceInfo * getTypeSourceInfo() const
Returns the declarator information for a base class or delegating initializer.
Definition: DeclCXX.h:2377
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:5440
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:937
void appendAutomaticObjDtor(VarDecl *VD, Stmt *S, BumpVectorContext &C)
Definition: CFG.h:928
bool isReferenceType() const
Definition: Type.h:6189
const CXXConstructExpr * getConstructExpr() const
Returns the CXXConstructExpr from this new-expression, or null.
Definition: ExprCXX.h:2026
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:1109
Expr * getSubExpr()
Definition: Expr.h:2855
void setTerminator(CFGTerminator Term)
Definition: CFG.h:835
Keeps track of the various options that can be enabled, which controls the dialect of C or C++ that i...
Definition: LangOptions.h:50
iterator end()
Definition: CFG.h:1079
Represents Objective-C&#39;s @catch statement.
Definition: StmtObjC.h:74
AdjacentBlocks::const_iterator const_succ_iterator
Definition: CFG.h:727
bool isGLValue() const
Definition: Expr.h:251
IndirectGotoStmt - This represents an indirect goto.
Definition: Stmt.h:1339
Describes an C or C++ initializer list.
Definition: Expr.h:3995
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:1980
ForStmt - This represents a &#39;for (init;cond;inc)&#39; stmt.
Definition: Stmt.h:1234
APValue Val
Val - This is the value the expression can be folded to.
Definition: Expr.h:572
LabelDecl * getDecl() const
Definition: Stmt.h:881
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:1756
Expr * getInitializer()
The initializer of this new-expression.
Definition: ExprCXX.h:2018
Stmt * getBody()
Definition: Stmt.h:1269
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:3102
Stmt * getInit()
Definition: Stmt.h:1248
CXXForRangeStmt - This represents C++0x [stmt.ranged]&#39;s ranged for statement, represented as &#39;for (ra...
Definition: StmtCXX.h:126
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:5432
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:5953
void appendLoopExit(const Stmt *LoopStmt, BumpVectorContext &C)
Definition: CFG.h:936
Expr * getCond()
Definition: Stmt.h:1267
bool isInt() const
Definition: APValue.h:234
CastExpr - Base class for type casts, including both implicit casts (ImplicitCastExpr) and explicit c...
Definition: Expr.h:2790
Represents binding an expression to a temporary.
Definition: ExprCXX.h:1217
CXXTemporary * getTemporary()
Definition: ExprCXX.h:1236
FieldDecl * getAnyMember() const
Definition: DeclCXX.h:2389
A C++ lambda expression, which produces a function object (of unspecified type) that can be invoked l...
Definition: ExprCXX.h:1611
bool hasTrivialDestructor() const
Determine whether this class has a trivial destructor (C++ [class.dtor]p3)
Definition: DeclCXX.h:1480
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:166
child_range children()
Definition: Stmt.h:711
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:848
bool getNoReturn() const
Definition: Type.h:3400
Stmt * getInit()
Definition: Stmt.h:992
arg_iterator placement_arg_end()
Definition: ExprCXX.h:2057
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:613
CXXRecordDecl * getAsCXXRecordDecl() const
Retrieves the CXXRecordDecl that this type refers to, either because the type is a RecordType or beca...
Definition: Type.cpp:1605
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3550
bool isDelegatingInitializer() const
Determine whether this initializer is creating a delegating constructor.
Definition: DeclCXX.h:2344
UnaryExprOrTypeTraitExpr - expression with either a type or (unevaluated) expression operand...
Definition: Expr.h:2107
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:3914
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:988
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:4708
This represents one expression.
Definition: Expr.h:105
Defines the clang::LangOptions interface.
Stmt * getTerminatorCondition(bool StripParens=true)
Definition: CFG.cpp:5446
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:156
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:1561
const Stmt * getThen() const
Definition: Stmt.h:997
BlockExpr - Adaptor class for mixing a BlockDecl with expressions.
Definition: Expr.h:4974
Represents a C++ destructor within a class.
Definition: DeclCXX.h:2697
bool succ_empty() const
Definition: CFG.h:770
VarDecl * getExceptionDecl() const
Definition: StmtCXX.h:50
unsigned getNumInits() const
Definition: Expr.h:4025
const Expr * getCallee() const
Definition: Expr.h:2325
Represents C++ constructor call.
Definition: CFG.h:151
QualType getArgumentType() const
Definition: Expr.h:2144
#define bool
Definition: stdbool.h:31
Stmt * getBody()
Definition: Stmt.h:1161
const CompoundStmt * getSynchBody() const
Definition: StmtObjC.h:282
ElementList::const_iterator const_iterator
Definition: CFG.h:696
Expr * getRHS()
Definition: Stmt.h:785
bool isTemporaryDtorsBranch() const
Definition: CFG.h:513
Represents Objective-C&#39;s @synchronized statement.
Definition: StmtObjC.h:262
SourceLocation Begin
CXXTryStmt - A C++ try block, including all handlers.
Definition: StmtCXX.h:65
const AstTypeMatcher< ArrayType > arrayType
Matches all kinds of arrays.
std::reverse_iterator< body_iterator > reverse_body_iterator
Definition: Stmt.h:679
QualType getType() const
Definition: Expr.h:127
static void print_initializer(raw_ostream &OS, StmtPrinterHelper &Helper, const CXXCtorInitializer *I)
Definition: CFG.cpp:4991
LabelDecl * getLabel() const
Definition: Stmt.h:1317
StorageDuration getStorageDuration() const
Retrieve the storage duration for the materialized temporary.
Definition: ExprCXX.h:4121
ReturnStmt - This represents a return, optionally of an expression: return; return 4;...
Definition: Stmt.h:1444
An expression that sends a message to the given Objective-C object or class.
Definition: ExprObjC.h:904
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:1784
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:6548
ValueDecl * getDecl()
Definition: Expr.h:1056
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:1240
bool isNull() const
Return true if this QualType doesn&#39;t point to a type yet.
Definition: Type.h:707
DoStmt - This represents a &#39;do/while&#39; stmt.
Definition: Stmt.h:1185
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:561
RecordDecl * getDecl() const
Definition: Type.h:4263
Expr * getArgument()
Definition: ExprCXX.h:2154
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:874
Kind
PseudoObjectExpr - An expression which accesses a pseudo-object l-value.
Definition: Expr.h:5096
Construction context can be seen as a linked list of multiple layers.
Encodes a location in the source.
Stmt * getLabel()
Definition: CFG.h:851
unsigned getNumHandlers() const
Definition: StmtCXX.h:103
Expr * getSubExpr() const
Definition: Expr.h:1811
Represents a C++ temporary.
Definition: ExprCXX.h:1185
const SwitchCase * getSwitchCaseList() const
Definition: Stmt.h:1077
Represents a new-expression for memory allocation and constructor calls, e.g: "new CXXNewExpr(foo)"...
Definition: ExprCXX.h:1873
Expr * getLHS()
Definition: Stmt.h:784
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:4644
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:505
bool PruneTriviallyFalseEdges
Definition: CFG.h:1017
reverse_body_iterator body_rend()
Definition: Stmt.h:685
QualType getBaseElementType(const ArrayType *VAT) const
Return the innermost element type of an array type.
const ConstantArrayType * getAsConstantArrayType(QualType T) const
Definition: ASTContext.h:2419
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:5213
const ArrayType * getAsArrayType(QualType T) const
Type Query functions.
bool isArray() const
Definition: ExprCXX.h:1978
decl_iterator decl_begin()
Definition: Stmt.h:556
bool isValueDependent() const
isValueDependent - Determines whether this expression is value-dependent (C++ [temp.dep.constexpr]).
Definition: Expr.h:148
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:563
ImplicitCastExpr - Allows us to explicitly represent implicit type conversions, which have no direct ...
Definition: Expr.h:2924
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:4028
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:3222
static const Expr * tryTransformToIntOrEnumConstant(const Expr *E)
Helper for tryNormalizeBinaryOperator.
Definition: CFG.cpp:75
void dump() const
Definition: CFG.cpp:5426
succ_iterator succ_end()
Definition: CFG.h:752
StmtExpr - This is the GNU Statement Expression extension: ({int X=4; X;}).
Definition: Expr.h:3611
bool isArgumentType() const
Definition: Expr.h:2143
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:1154
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:3146
Defines various enumerations that describe declaration and type specifiers.
AddrLabelExpr - The GNU address of label extension, representing &&label.
Definition: Expr.h:3567
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:3508
VarDecl * getConditionVariable() const
Retrieve the variable declared in this "if" statement, if any.
Definition: Stmt.cpp:813
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:1267
EvalResult is a struct with detailed info about an evaluated expression.
Definition: Expr.h:570
Represents a delete expression for memory deallocation and destructor calls, e.g. ...
Definition: ExprCXX.h:2100
ArrayRef< Capture > captures() const
Definition: Decl.h:3954
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:1217
unsigned pred_size() const
Definition: CFG.h:772
StmtClass getStmtClass() const
Definition: Stmt.h:391
static StmtPrinterHelper * GraphHelper
Definition: CFG.cpp:5516
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:2163
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:957
const Decl * getSingleDecl() const
Definition: Stmt.h:522
FunctionType::ExtInfo getFunctionExtInfo(const Type &t)
Definition: Type.h:6078
const Expr * getSynchExpr() const
Definition: StmtObjC.h:290
void appendMemberDtor(FieldDecl *FD, BumpVectorContext &C)
Definition: CFG.h:920
void appendInitializer(CXXCtorInitializer *initializer, BumpVectorContext &C)
Definition: CFG.h:888
This class represents a potential adjacent block in the CFG.
Definition: CFG.h:621
bool isSingleDecl() const
isSingleDecl - This method returns true if this DeclStmt refers to a single Decl. ...
Definition: Stmt.h:518
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:1076
llvm::APInt getValue() const
Definition: Expr.h:1295
Represents a __leave statement.
Definition: Stmt.h:2042
LabelDecl * getLabel() const
Definition: Expr.h:3589
SwitchStmt - This represents a &#39;switch&#39; stmt.
Definition: Stmt.h:1037
Pointer to a block type.
Definition: Type.h:2613
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:4253
bool body_empty() const
Definition: Stmt.h:638
Represents Objective-C&#39;s collection statement.
Definition: StmtObjC.h:24
AbstractConditionalOperator - An abstract base class for ConditionalOperator and BinaryConditionalOpe...
Definition: Expr.h:3350
Represents a C++ base or member initializer.
Definition: DeclCXX.h:2250
reverse_decl_iterator decl_rend()
Definition: Stmt.h:567
const ConstructionContextItem & getItem() const
Stmt * getInit()
Definition: Stmt.h:1072
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:5399
CanQualType BoundMemberTy
Definition: ASTContext.h:1054
decl_range decls()
Definition: Stmt.h:550
static void print_construction_context(raw_ostream &OS, StmtPrinterHelper &Helper, const ConstructionContext *CC)
Definition: CFG.cpp:5012
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:2054
DeclStmt * getRangeStmt()
Definition: StmtCXX.h:152
Expr * getRHS() const
Definition: Expr.h:3836
SEHFinallyStmt * getFinallyHandler() const
Definition: Stmt.cpp:961
GotoStmt - This represents a direct goto.
Definition: Stmt.h:1305
A use of a default initializer in a constructor or in aggregate initialization.
Definition: ExprCXX.h:1134
Expr * getTarget()
Definition: Stmt.h:1359
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:13824
void setHasNoReturnElement()
Definition: CFG.h:838
Expr * getCond()
Definition: Stmt.h:1203
Defines the C++ Decl subclasses, other than those for templates (found in DeclTemplate.h) and friends (in DeclFriend.h).
void printPretty(raw_ostream &OS, PrinterHelper *Helper, const PrintingPolicy &Policy, unsigned Indentation=0, StringRef NewlineSymbol="\, const ASTContext *Context=nullptr) const
MemberExpr - [C99 6.5.2.3] Structure and Union Members.
Definition: Expr.h:2467
void viewCFG(const LangOptions &LO) const
Definition: CFG.cpp:5519
Defines the clang::SourceLocation class and associated facilities.
ConstructionContext&#39;s subclasses describe different ways of constructing an object in C++...