clang  7.0.0svn
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 *VisitPseudoObjectExpr(PseudoObjectExpr *E);
573  CFGBlock *VisitReturnStmt(ReturnStmt *R);
574  CFGBlock *VisitSEHExceptStmt(SEHExceptStmt *S);
575  CFGBlock *VisitSEHFinallyStmt(SEHFinallyStmt *S);
576  CFGBlock *VisitSEHLeaveStmt(SEHLeaveStmt *S);
577  CFGBlock *VisitSEHTryStmt(SEHTryStmt *S);
578  CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc);
579  CFGBlock *VisitSwitchStmt(SwitchStmt *S);
580  CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
581  AddStmtChoice asc);
582  CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc);
583  CFGBlock *VisitWhileStmt(WhileStmt *W);
584 
585  CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd);
586  CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc);
587  CFGBlock *VisitChildren(Stmt *S);
588  CFGBlock *VisitNoRecurse(Expr *E, AddStmtChoice asc);
589 
590  void maybeAddScopeBeginForVarDecl(CFGBlock *B, const VarDecl *VD,
591  const Stmt *S) {
592  if (ScopePos && (VD == ScopePos.getFirstVarInScope()))
593  appendScopeBegin(B, VD, S);
594  }
595 
596  /// When creating the CFG for temporary destructors, we want to mirror the
597  /// branch structure of the corresponding constructor calls.
598  /// Thus, while visiting a statement for temporary destructors, we keep a
599  /// context to keep track of the following information:
600  /// - whether a subexpression is executed unconditionally
601  /// - if a subexpression is executed conditionally, the first
602  /// CXXBindTemporaryExpr we encounter in that subexpression (which
603  /// corresponds to the last temporary destructor we have to call for this
604  /// subexpression) and the CFG block at that point (which will become the
605  /// successor block when inserting the decision point).
606  ///
607  /// That way, we can build the branch structure for temporary destructors as
608  /// follows:
609  /// 1. If a subexpression is executed unconditionally, we add the temporary
610  /// destructor calls to the current block.
611  /// 2. If a subexpression is executed conditionally, when we encounter a
612  /// CXXBindTemporaryExpr:
613  /// a) If it is the first temporary destructor call in the subexpression,
614  /// we remember the CXXBindTemporaryExpr and the current block in the
615  /// TempDtorContext; we start a new block, and insert the temporary
616  /// destructor call.
617  /// b) Otherwise, add the temporary destructor call to the current block.
618  /// 3. When we finished visiting a conditionally executed subexpression,
619  /// and we found at least one temporary constructor during the visitation
620  /// (2.a has executed), we insert a decision block that uses the
621  /// CXXBindTemporaryExpr as terminator, and branches to the current block
622  /// if the CXXBindTemporaryExpr was marked executed, and otherwise
623  /// branches to the stored successor.
624  struct TempDtorContext {
625  TempDtorContext() = default;
626  TempDtorContext(TryResult KnownExecuted)
627  : IsConditional(true), KnownExecuted(KnownExecuted) {}
628 
629  /// Returns whether we need to start a new branch for a temporary destructor
630  /// call. This is the case when the temporary destructor is
631  /// conditionally executed, and it is the first one we encounter while
632  /// visiting a subexpression - other temporary destructors at the same level
633  /// will be added to the same block and are executed under the same
634  /// condition.
635  bool needsTempDtorBranch() const {
636  return IsConditional && !TerminatorExpr;
637  }
638 
639  /// Remember the successor S of a temporary destructor decision branch for
640  /// the corresponding CXXBindTemporaryExpr E.
641  void setDecisionPoint(CFGBlock *S, CXXBindTemporaryExpr *E) {
642  Succ = S;
643  TerminatorExpr = E;
644  }
645 
646  const bool IsConditional = false;
647  const TryResult KnownExecuted = true;
648  CFGBlock *Succ = nullptr;
649  CXXBindTemporaryExpr *TerminatorExpr = nullptr;
650  };
651 
652  // Visitors to walk an AST and generate destructors of temporaries in
653  // full expression.
654  CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary,
655  TempDtorContext &Context);
656  CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E, TempDtorContext &Context);
657  CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E,
658  TempDtorContext &Context);
659  CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(
660  CXXBindTemporaryExpr *E, bool BindToTemporary, TempDtorContext &Context);
661  CFGBlock *VisitConditionalOperatorForTemporaryDtors(
662  AbstractConditionalOperator *E, bool BindToTemporary,
663  TempDtorContext &Context);
664  void InsertTempDtorDecisionBlock(const TempDtorContext &Context,
665  CFGBlock *FalseSucc = nullptr);
666 
667  // NYS == Not Yet Supported
668  CFGBlock *NYS() {
669  badCFG = true;
670  return Block;
671  }
672 
673  // Remember to apply the construction context based on the current \p Layer
674  // when constructing the CFG element for \p CE.
675  void consumeConstructionContext(const ConstructionContextLayer *Layer,
676  Expr *E);
677 
678  // Scan \p Child statement to find constructors in it, while keeping in mind
679  // that its parent statement is providing a partial construction context
680  // described by \p Layer. If a constructor is found, it would be assigned
681  // the context based on the layer. If an additional construction context layer
682  // is found, the function recurses into that.
683  void findConstructionContexts(const ConstructionContextLayer *Layer,
684  Stmt *Child);
685 
686  // Unset the construction context after consuming it. This is done immediately
687  // after adding the CFGConstructor or CFGCXXRecordTypedCall element, so
688  // there's no need to do this manually in every Visit... function.
689  void cleanupConstructionContext(Expr *E);
690 
691  void autoCreateBlock() { if (!Block) Block = createBlock(); }
692  CFGBlock *createBlock(bool add_successor = true);
693  CFGBlock *createNoReturnBlock();
694 
695  CFGBlock *addStmt(Stmt *S) {
696  return Visit(S, AddStmtChoice::AlwaysAdd);
697  }
698 
699  CFGBlock *addInitializer(CXXCtorInitializer *I);
700  void addLoopExit(const Stmt *LoopStmt);
701  void addAutomaticObjDtors(LocalScope::const_iterator B,
702  LocalScope::const_iterator E, Stmt *S);
703  void addLifetimeEnds(LocalScope::const_iterator B,
704  LocalScope::const_iterator E, Stmt *S);
705  void addAutomaticObjHandling(LocalScope::const_iterator B,
706  LocalScope::const_iterator E, Stmt *S);
707  void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD);
708  void addScopesEnd(LocalScope::const_iterator B, LocalScope::const_iterator E,
709  Stmt *S);
710 
711  void getDeclsWithEndedScope(LocalScope::const_iterator B,
712  LocalScope::const_iterator E, Stmt *S);
713 
714  // Local scopes creation.
715  LocalScope* createOrReuseLocalScope(LocalScope* Scope);
716 
717  void addLocalScopeForStmt(Stmt *S);
718  LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS,
719  LocalScope* Scope = nullptr);
720  LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = nullptr);
721 
722  void addLocalScopeAndDtors(Stmt *S);
723 
724  // Interface to CFGBlock - adding CFGElements.
725 
726  void appendStmt(CFGBlock *B, const Stmt *S) {
727  if (alwaysAdd(S) && cachedEntry)
728  cachedEntry->second = B;
729 
730  // All block-level expressions should have already been IgnoreParens()ed.
731  assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S);
732  B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext());
733  }
734 
735  void appendConstructor(CFGBlock *B, CXXConstructExpr *CE) {
736  if (BuildOpts.AddRichCXXConstructors) {
737  if (const ConstructionContextLayer *Layer =
738  ConstructionContextMap.lookup(CE)) {
739  cleanupConstructionContext(CE);
740  if (const auto *CC = ConstructionContext::createFromLayers(
741  cfg->getBumpVectorContext(), Layer)) {
742  B->appendConstructor(CE, CC, cfg->getBumpVectorContext());
743  return;
744  }
745  }
746  }
747 
748  // No valid construction context found. Fall back to statement.
749  B->appendStmt(CE, cfg->getBumpVectorContext());
750  }
751 
752  void appendCall(CFGBlock *B, CallExpr *CE) {
753  if (alwaysAdd(CE) && cachedEntry)
754  cachedEntry->second = B;
755 
756  if (BuildOpts.AddRichCXXConstructors) {
758  if (const ConstructionContextLayer *Layer =
759  ConstructionContextMap.lookup(CE)) {
760  cleanupConstructionContext(CE);
761  if (const auto *CC = ConstructionContext::createFromLayers(
762  cfg->getBumpVectorContext(), Layer)) {
763  B->appendCXXRecordTypedCall(CE, CC, cfg->getBumpVectorContext());
764  return;
765  }
766  }
767  }
768  }
769 
770  // No valid construction context found. Fall back to statement.
771  B->appendStmt(CE, cfg->getBumpVectorContext());
772  }
773 
774  void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) {
775  B->appendInitializer(I, cfg->getBumpVectorContext());
776  }
777 
778  void appendNewAllocator(CFGBlock *B, CXXNewExpr *NE) {
779  B->appendNewAllocator(NE, cfg->getBumpVectorContext());
780  }
781 
782  void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) {
783  B->appendBaseDtor(BS, cfg->getBumpVectorContext());
784  }
785 
786  void appendMemberDtor(CFGBlock *B, FieldDecl *FD) {
787  B->appendMemberDtor(FD, cfg->getBumpVectorContext());
788  }
789 
790  void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) {
791  B->appendTemporaryDtor(E, cfg->getBumpVectorContext());
792  }
793 
794  void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) {
795  B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext());
796  }
797 
798  void appendLifetimeEnds(CFGBlock *B, VarDecl *VD, Stmt *S) {
799  B->appendLifetimeEnds(VD, S, cfg->getBumpVectorContext());
800  }
801 
802  void appendLoopExit(CFGBlock *B, const Stmt *LoopStmt) {
803  B->appendLoopExit(LoopStmt, cfg->getBumpVectorContext());
804  }
805 
806  void appendDeleteDtor(CFGBlock *B, CXXRecordDecl *RD, CXXDeleteExpr *DE) {
807  B->appendDeleteDtor(RD, DE, cfg->getBumpVectorContext());
808  }
809 
810  void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
811  LocalScope::const_iterator B, LocalScope::const_iterator E);
812 
813  void prependAutomaticObjLifetimeWithTerminator(CFGBlock *Blk,
814  LocalScope::const_iterator B,
815  LocalScope::const_iterator E);
816 
817  const VarDecl *
818  prependAutomaticObjScopeEndWithTerminator(CFGBlock *Blk,
819  LocalScope::const_iterator B,
820  LocalScope::const_iterator E);
821 
822  void addSuccessor(CFGBlock *B, CFGBlock *S, bool IsReachable = true) {
823  B->addSuccessor(CFGBlock::AdjacentBlock(S, IsReachable),
824  cfg->getBumpVectorContext());
825  }
826 
827  /// Add a reachable successor to a block, with the alternate variant that is
828  /// unreachable.
829  void addSuccessor(CFGBlock *B, CFGBlock *ReachableBlock, CFGBlock *AltBlock) {
830  B->addSuccessor(CFGBlock::AdjacentBlock(ReachableBlock, AltBlock),
831  cfg->getBumpVectorContext());
832  }
833 
834  void appendScopeBegin(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
835  if (BuildOpts.AddScopes)
836  B->appendScopeBegin(VD, S, cfg->getBumpVectorContext());
837  }
838 
839  void prependScopeBegin(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
840  if (BuildOpts.AddScopes)
841  B->prependScopeBegin(VD, S, cfg->getBumpVectorContext());
842  }
843 
844  void appendScopeEnd(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
845  if (BuildOpts.AddScopes)
846  B->appendScopeEnd(VD, S, cfg->getBumpVectorContext());
847  }
848 
849  void prependScopeEnd(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
850  if (BuildOpts.AddScopes)
851  B->prependScopeEnd(VD, S, cfg->getBumpVectorContext());
852  }
853 
854  /// Find a relational comparison with an expression evaluating to a
855  /// boolean and a constant other than 0 and 1.
856  /// e.g. if ((x < y) == 10)
857  TryResult checkIncorrectRelationalOperator(const BinaryOperator *B) {
858  const Expr *LHSExpr = B->getLHS()->IgnoreParens();
859  const Expr *RHSExpr = B->getRHS()->IgnoreParens();
860 
861  const IntegerLiteral *IntLiteral = dyn_cast<IntegerLiteral>(LHSExpr);
862  const Expr *BoolExpr = RHSExpr;
863  bool IntFirst = true;
864  if (!IntLiteral) {
865  IntLiteral = dyn_cast<IntegerLiteral>(RHSExpr);
866  BoolExpr = LHSExpr;
867  IntFirst = false;
868  }
869 
870  if (!IntLiteral || !BoolExpr->isKnownToHaveBooleanValue())
871  return TryResult();
872 
873  llvm::APInt IntValue = IntLiteral->getValue();
874  if ((IntValue == 1) || (IntValue == 0))
875  return TryResult();
876 
877  bool IntLarger = IntLiteral->getType()->isUnsignedIntegerType() ||
878  !IntValue.isNegative();
879 
880  BinaryOperatorKind Bok = B->getOpcode();
881  if (Bok == BO_GT || Bok == BO_GE) {
882  // Always true for 10 > bool and bool > -1
883  // Always false for -1 > bool and bool > 10
884  return TryResult(IntFirst == IntLarger);
885  } else {
886  // Always true for -1 < bool and bool < 10
887  // Always false for 10 < bool and bool < -1
888  return TryResult(IntFirst != IntLarger);
889  }
890  }
891 
892  /// Find an incorrect equality comparison. Either with an expression
893  /// evaluating to a boolean and a constant other than 0 and 1.
894  /// e.g. if (!x == 10) or a bitwise and/or operation that always evaluates to
895  /// true/false e.q. (x & 8) == 4.
896  TryResult checkIncorrectEqualityOperator(const BinaryOperator *B) {
897  const Expr *LHSExpr = B->getLHS()->IgnoreParens();
898  const Expr *RHSExpr = B->getRHS()->IgnoreParens();
899 
900  const IntegerLiteral *IntLiteral = dyn_cast<IntegerLiteral>(LHSExpr);
901  const Expr *BoolExpr = RHSExpr;
902 
903  if (!IntLiteral) {
904  IntLiteral = dyn_cast<IntegerLiteral>(RHSExpr);
905  BoolExpr = LHSExpr;
906  }
907 
908  if (!IntLiteral)
909  return TryResult();
910 
911  const BinaryOperator *BitOp = dyn_cast<BinaryOperator>(BoolExpr);
912  if (BitOp && (BitOp->getOpcode() == BO_And ||
913  BitOp->getOpcode() == BO_Or)) {
914  const Expr *LHSExpr2 = BitOp->getLHS()->IgnoreParens();
915  const Expr *RHSExpr2 = BitOp->getRHS()->IgnoreParens();
916 
917  const IntegerLiteral *IntLiteral2 = dyn_cast<IntegerLiteral>(LHSExpr2);
918 
919  if (!IntLiteral2)
920  IntLiteral2 = dyn_cast<IntegerLiteral>(RHSExpr2);
921 
922  if (!IntLiteral2)
923  return TryResult();
924 
925  llvm::APInt L1 = IntLiteral->getValue();
926  llvm::APInt L2 = IntLiteral2->getValue();
927  if ((BitOp->getOpcode() == BO_And && (L2 & L1) != L1) ||
928  (BitOp->getOpcode() == BO_Or && (L2 | L1) != L1)) {
929  if (BuildOpts.Observer)
930  BuildOpts.Observer->compareBitwiseEquality(B,
931  B->getOpcode() != BO_EQ);
932  TryResult(B->getOpcode() != BO_EQ);
933  }
934  } else if (BoolExpr->isKnownToHaveBooleanValue()) {
935  llvm::APInt IntValue = IntLiteral->getValue();
936  if ((IntValue == 1) || (IntValue == 0)) {
937  return TryResult();
938  }
939  return TryResult(B->getOpcode() != BO_EQ);
940  }
941 
942  return TryResult();
943  }
944 
945  TryResult analyzeLogicOperatorCondition(BinaryOperatorKind Relation,
946  const llvm::APSInt &Value1,
947  const llvm::APSInt &Value2) {
948  assert(Value1.isSigned() == Value2.isSigned());
949  switch (Relation) {
950  default:
951  return TryResult();
952  case BO_EQ:
953  return TryResult(Value1 == Value2);
954  case BO_NE:
955  return TryResult(Value1 != Value2);
956  case BO_LT:
957  return TryResult(Value1 < Value2);
958  case BO_LE:
959  return TryResult(Value1 <= Value2);
960  case BO_GT:
961  return TryResult(Value1 > Value2);
962  case BO_GE:
963  return TryResult(Value1 >= Value2);
964  }
965  }
966 
967  /// Find a pair of comparison expressions with or without parentheses
968  /// with a shared variable and constants and a logical operator between them
969  /// that always evaluates to either true or false.
970  /// e.g. if (x != 3 || x != 4)
971  TryResult checkIncorrectLogicOperator(const BinaryOperator *B) {
972  assert(B->isLogicalOp());
973  const BinaryOperator *LHS =
974  dyn_cast<BinaryOperator>(B->getLHS()->IgnoreParens());
975  const BinaryOperator *RHS =
976  dyn_cast<BinaryOperator>(B->getRHS()->IgnoreParens());
977  if (!LHS || !RHS)
978  return {};
979 
980  if (!LHS->isComparisonOp() || !RHS->isComparisonOp())
981  return {};
982 
983  const DeclRefExpr *Decl1;
984  const Expr *Expr1;
985  BinaryOperatorKind BO1;
986  std::tie(Decl1, BO1, Expr1) = tryNormalizeBinaryOperator(LHS);
987 
988  if (!Decl1 || !Expr1)
989  return {};
990 
991  const DeclRefExpr *Decl2;
992  const Expr *Expr2;
993  BinaryOperatorKind BO2;
994  std::tie(Decl2, BO2, Expr2) = tryNormalizeBinaryOperator(RHS);
995 
996  if (!Decl2 || !Expr2)
997  return {};
998 
999  // Check that it is the same variable on both sides.
1000  if (Decl1->getDecl() != Decl2->getDecl())
1001  return {};
1002 
1003  // Make sure the user's intent is clear (e.g. they're comparing against two
1004  // int literals, or two things from the same enum)
1005  if (!areExprTypesCompatible(Expr1, Expr2))
1006  return {};
1007 
1008  llvm::APSInt L1, L2;
1009 
1010  if (!Expr1->EvaluateAsInt(L1, *Context) ||
1011  !Expr2->EvaluateAsInt(L2, *Context))
1012  return {};
1013 
1014  // Can't compare signed with unsigned or with different bit width.
1015  if (L1.isSigned() != L2.isSigned() || L1.getBitWidth() != L2.getBitWidth())
1016  return {};
1017 
1018  // Values that will be used to determine if result of logical
1019  // operator is always true/false
1020  const llvm::APSInt Values[] = {
1021  // Value less than both Value1 and Value2
1022  llvm::APSInt::getMinValue(L1.getBitWidth(), L1.isUnsigned()),
1023  // L1
1024  L1,
1025  // Value between Value1 and Value2
1026  ((L1 < L2) ? L1 : L2) + llvm::APSInt(llvm::APInt(L1.getBitWidth(), 1),
1027  L1.isUnsigned()),
1028  // L2
1029  L2,
1030  // Value greater than both Value1 and Value2
1031  llvm::APSInt::getMaxValue(L1.getBitWidth(), L1.isUnsigned()),
1032  };
1033 
1034  // Check whether expression is always true/false by evaluating the following
1035  // * variable x is less than the smallest literal.
1036  // * variable x is equal to the smallest literal.
1037  // * Variable x is between smallest and largest literal.
1038  // * Variable x is equal to the largest literal.
1039  // * Variable x is greater than largest literal.
1040  bool AlwaysTrue = true, AlwaysFalse = true;
1041  for (const llvm::APSInt &Value : Values) {
1042  TryResult Res1, Res2;
1043  Res1 = analyzeLogicOperatorCondition(BO1, Value, L1);
1044  Res2 = analyzeLogicOperatorCondition(BO2, Value, L2);
1045 
1046  if (!Res1.isKnown() || !Res2.isKnown())
1047  return {};
1048 
1049  if (B->getOpcode() == BO_LAnd) {
1050  AlwaysTrue &= (Res1.isTrue() && Res2.isTrue());
1051  AlwaysFalse &= !(Res1.isTrue() && Res2.isTrue());
1052  } else {
1053  AlwaysTrue &= (Res1.isTrue() || Res2.isTrue());
1054  AlwaysFalse &= !(Res1.isTrue() || Res2.isTrue());
1055  }
1056  }
1057 
1058  if (AlwaysTrue || AlwaysFalse) {
1059  if (BuildOpts.Observer)
1060  BuildOpts.Observer->compareAlwaysTrue(B, AlwaysTrue);
1061  return TryResult(AlwaysTrue);
1062  }
1063  return {};
1064  }
1065 
1066  /// Try and evaluate an expression to an integer constant.
1067  bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) {
1068  if (!BuildOpts.PruneTriviallyFalseEdges)
1069  return false;
1070  return !S->isTypeDependent() &&
1071  !S->isValueDependent() &&
1072  S->EvaluateAsRValue(outResult, *Context);
1073  }
1074 
1075  /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1
1076  /// if we can evaluate to a known value, otherwise return -1.
1077  TryResult tryEvaluateBool(Expr *S) {
1078  if (!BuildOpts.PruneTriviallyFalseEdges ||
1079  S->isTypeDependent() || S->isValueDependent())
1080  return {};
1081 
1082  if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(S)) {
1083  if (Bop->isLogicalOp()) {
1084  // Check the cache first.
1085  CachedBoolEvalsTy::iterator I = CachedBoolEvals.find(S);
1086  if (I != CachedBoolEvals.end())
1087  return I->second; // already in map;
1088 
1089  // Retrieve result at first, or the map might be updated.
1090  TryResult Result = evaluateAsBooleanConditionNoCache(S);
1091  CachedBoolEvals[S] = Result; // update or insert
1092  return Result;
1093  }
1094  else {
1095  switch (Bop->getOpcode()) {
1096  default: break;
1097  // For 'x & 0' and 'x * 0', we can determine that
1098  // the value is always false.
1099  case BO_Mul:
1100  case BO_And: {
1101  // If either operand is zero, we know the value
1102  // must be false.
1103  llvm::APSInt IntVal;
1104  if (Bop->getLHS()->EvaluateAsInt(IntVal, *Context)) {
1105  if (!IntVal.getBoolValue()) {
1106  return TryResult(false);
1107  }
1108  }
1109  if (Bop->getRHS()->EvaluateAsInt(IntVal, *Context)) {
1110  if (!IntVal.getBoolValue()) {
1111  return TryResult(false);
1112  }
1113  }
1114  }
1115  break;
1116  }
1117  }
1118  }
1119 
1120  return evaluateAsBooleanConditionNoCache(S);
1121  }
1122 
1123  /// Evaluate as boolean \param E without using the cache.
1124  TryResult evaluateAsBooleanConditionNoCache(Expr *E) {
1125  if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(E)) {
1126  if (Bop->isLogicalOp()) {
1127  TryResult LHS = tryEvaluateBool(Bop->getLHS());
1128  if (LHS.isKnown()) {
1129  // We were able to evaluate the LHS, see if we can get away with not
1130  // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
1131  if (LHS.isTrue() == (Bop->getOpcode() == BO_LOr))
1132  return LHS.isTrue();
1133 
1134  TryResult RHS = tryEvaluateBool(Bop->getRHS());
1135  if (RHS.isKnown()) {
1136  if (Bop->getOpcode() == BO_LOr)
1137  return LHS.isTrue() || RHS.isTrue();
1138  else
1139  return LHS.isTrue() && RHS.isTrue();
1140  }
1141  } else {
1142  TryResult RHS = tryEvaluateBool(Bop->getRHS());
1143  if (RHS.isKnown()) {
1144  // We can't evaluate the LHS; however, sometimes the result
1145  // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
1146  if (RHS.isTrue() == (Bop->getOpcode() == BO_LOr))
1147  return RHS.isTrue();
1148  } else {
1149  TryResult BopRes = checkIncorrectLogicOperator(Bop);
1150  if (BopRes.isKnown())
1151  return BopRes.isTrue();
1152  }
1153  }
1154 
1155  return {};
1156  } else if (Bop->isEqualityOp()) {
1157  TryResult BopRes = checkIncorrectEqualityOperator(Bop);
1158  if (BopRes.isKnown())
1159  return BopRes.isTrue();
1160  } else if (Bop->isRelationalOp()) {
1161  TryResult BopRes = checkIncorrectRelationalOperator(Bop);
1162  if (BopRes.isKnown())
1163  return BopRes.isTrue();
1164  }
1165  }
1166 
1167  bool Result;
1168  if (E->EvaluateAsBooleanCondition(Result, *Context))
1169  return Result;
1170 
1171  return {};
1172  }
1173 
1174  bool hasTrivialDestructor(VarDecl *VD);
1175 };
1176 
1177 } // namespace
1178 
1179 inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder,
1180  const Stmt *stmt) const {
1181  return builder.alwaysAdd(stmt) || kind == AlwaysAdd;
1182 }
1183 
1184 bool CFGBuilder::alwaysAdd(const Stmt *stmt) {
1185  bool shouldAdd = BuildOpts.alwaysAdd(stmt);
1186 
1187  if (!BuildOpts.forcedBlkExprs)
1188  return shouldAdd;
1189 
1190  if (lastLookup == stmt) {
1191  if (cachedEntry) {
1192  assert(cachedEntry->first == stmt);
1193  return true;
1194  }
1195  return shouldAdd;
1196  }
1197 
1198  lastLookup = stmt;
1199 
1200  // Perform the lookup!
1201  CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs;
1202 
1203  if (!fb) {
1204  // No need to update 'cachedEntry', since it will always be null.
1205  assert(!cachedEntry);
1206  return shouldAdd;
1207  }
1208 
1209  CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt);
1210  if (itr == fb->end()) {
1211  cachedEntry = nullptr;
1212  return shouldAdd;
1213  }
1214 
1215  cachedEntry = &*itr;
1216  return true;
1217 }
1218 
1219 // FIXME: Add support for dependent-sized array types in C++?
1220 // Does it even make sense to build a CFG for an uninstantiated template?
1221 static const VariableArrayType *FindVA(const Type *t) {
1222  while (const ArrayType *vt = dyn_cast<ArrayType>(t)) {
1223  if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt))
1224  if (vat->getSizeExpr())
1225  return vat;
1226 
1227  t = vt->getElementType().getTypePtr();
1228  }
1229 
1230  return nullptr;
1231 }
1232 
1233 void CFGBuilder::consumeConstructionContext(
1234  const ConstructionContextLayer *Layer, Expr *E) {
1235  if (const ConstructionContextLayer *PreviouslyStoredLayer =
1236  ConstructionContextMap.lookup(E)) {
1237  (void)PreviouslyStoredLayer;
1238  // We might have visited this child when we were finding construction
1239  // contexts within its parents.
1240  assert(PreviouslyStoredLayer->isStrictlyMoreSpecificThan(Layer) &&
1241  "Already within a different construction context!");
1242  } else {
1243  ConstructionContextMap[E] = Layer;
1244  }
1245 }
1246 
1247 void CFGBuilder::findConstructionContexts(
1248  const ConstructionContextLayer *Layer, Stmt *Child) {
1249  if (!BuildOpts.AddRichCXXConstructors)
1250  return;
1251 
1252  if (!Child)
1253  return;
1254 
1255  switch(Child->getStmtClass()) {
1256  case Stmt::CXXConstructExprClass:
1257  case Stmt::CXXTemporaryObjectExprClass: {
1258  consumeConstructionContext(Layer, cast<CXXConstructExpr>(Child));
1259  break;
1260  }
1261  // FIXME: This, like the main visit, doesn't support CUDAKernelCallExpr.
1262  // FIXME: An isa<> would look much better but this whole switch is a
1263  // workaround for an internal compiler error in MSVC 2015 (see r326021).
1264  case Stmt::CallExprClass:
1265  case Stmt::CXXMemberCallExprClass:
1266  case Stmt::CXXOperatorCallExprClass:
1267  case Stmt::UserDefinedLiteralClass: {
1268  auto *CE = cast<CallExpr>(Child);
1270  consumeConstructionContext(Layer, CE);
1271  break;
1272  }
1273  case Stmt::ExprWithCleanupsClass: {
1274  auto *Cleanups = cast<ExprWithCleanups>(Child);
1275  findConstructionContexts(Layer, Cleanups->getSubExpr());
1276  break;
1277  }
1278  case Stmt::CXXFunctionalCastExprClass: {
1279  auto *Cast = cast<CXXFunctionalCastExpr>(Child);
1280  findConstructionContexts(Layer, Cast->getSubExpr());
1281  break;
1282  }
1283  case Stmt::ImplicitCastExprClass: {
1284  auto *Cast = cast<ImplicitCastExpr>(Child);
1285  // Should we support other implicit cast kinds?
1286  switch (Cast->getCastKind()) {
1287  case CK_NoOp:
1288  case CK_ConstructorConversion:
1289  findConstructionContexts(Layer, Cast->getSubExpr());
1290  default:
1291  break;
1292  }
1293  break;
1294  }
1295  case Stmt::CXXBindTemporaryExprClass: {
1296  auto *BTE = cast<CXXBindTemporaryExpr>(Child);
1297  findConstructionContexts(
1298  ConstructionContextLayer::create(cfg->getBumpVectorContext(),
1299  BTE, Layer),
1300  BTE->getSubExpr());
1301  break;
1302  }
1303  case Stmt::ConditionalOperatorClass: {
1304  auto *CO = cast<ConditionalOperator>(Child);
1305  if (!dyn_cast_or_null<MaterializeTemporaryExpr>(Layer->getTriggerStmt())) {
1306  // If the object returned by the conditional operator is not going to be a
1307  // temporary object that needs to be immediately materialized, then
1308  // it must be C++17 with its mandatory copy elision. Do not yet promise
1309  // to support this case.
1310  assert(!CO->getType()->getAsCXXRecordDecl() || CO->isGLValue() ||
1311  Context->getLangOpts().CPlusPlus17);
1312  break;
1313  }
1314  findConstructionContexts(Layer, CO->getLHS());
1315  findConstructionContexts(Layer, CO->getRHS());
1316  break;
1317  }
1318  default:
1319  break;
1320  }
1321 }
1322 
1323 void CFGBuilder::cleanupConstructionContext(Expr *E) {
1324  assert(BuildOpts.AddRichCXXConstructors &&
1325  "We should not be managing construction contexts!");
1326  assert(ConstructionContextMap.count(E) &&
1327  "Cannot exit construction context without the context!");
1328  ConstructionContextMap.erase(E);
1329 }
1330 
1331 
1332 /// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an
1333 /// arbitrary statement. Examples include a single expression or a function
1334 /// body (compound statement). The ownership of the returned CFG is
1335 /// transferred to the caller. If CFG construction fails, this method returns
1336 /// NULL.
1337 std::unique_ptr<CFG> CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) {
1338  assert(cfg.get());
1339  if (!Statement)
1340  return nullptr;
1341 
1342  // Create an empty block that will serve as the exit block for the CFG. Since
1343  // this is the first block added to the CFG, it will be implicitly registered
1344  // as the exit block.
1345  Succ = createBlock();
1346  assert(Succ == &cfg->getExit());
1347  Block = nullptr; // the EXIT block is empty. Create all other blocks lazily.
1348 
1349  assert(!(BuildOpts.AddImplicitDtors && BuildOpts.AddLifetime) &&
1350  "AddImplicitDtors and AddLifetime cannot be used at the same time");
1351 
1352  if (BuildOpts.AddImplicitDtors)
1353  if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D))
1354  addImplicitDtorsForDestructor(DD);
1355 
1356  // Visit the statements and create the CFG.
1357  CFGBlock *B = addStmt(Statement);
1358 
1359  if (badCFG)
1360  return nullptr;
1361 
1362  // For C++ constructor add initializers to CFG.
1363  if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) {
1364  for (auto *I : llvm::reverse(CD->inits())) {
1365  B = addInitializer(I);
1366  if (badCFG)
1367  return nullptr;
1368  }
1369  }
1370 
1371  if (B)
1372  Succ = B;
1373 
1374  // Backpatch the gotos whose label -> block mappings we didn't know when we
1375  // encountered them.
1376  for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(),
1377  E = BackpatchBlocks.end(); I != E; ++I ) {
1378 
1379  CFGBlock *B = I->block;
1380  const GotoStmt *G = cast<GotoStmt>(B->getTerminator());
1381  LabelMapTy::iterator LI = LabelMap.find(G->getLabel());
1382 
1383  // If there is no target for the goto, then we are looking at an
1384  // incomplete AST. Handle this by not registering a successor.
1385  if (LI == LabelMap.end()) continue;
1386 
1387  JumpTarget JT = LI->second;
1388  prependAutomaticObjLifetimeWithTerminator(B, I->scopePosition,
1389  JT.scopePosition);
1390  prependAutomaticObjDtorsWithTerminator(B, I->scopePosition,
1391  JT.scopePosition);
1392  const VarDecl *VD = prependAutomaticObjScopeEndWithTerminator(
1393  B, I->scopePosition, JT.scopePosition);
1394  appendScopeBegin(JT.block, VD, G);
1395  addSuccessor(B, JT.block);
1396  }
1397 
1398  // Add successors to the Indirect Goto Dispatch block (if we have one).
1399  if (CFGBlock *B = cfg->getIndirectGotoBlock())
1400  for (LabelSetTy::iterator I = AddressTakenLabels.begin(),
1401  E = AddressTakenLabels.end(); I != E; ++I ) {
1402  // Lookup the target block.
1403  LabelMapTy::iterator LI = LabelMap.find(*I);
1404 
1405  // If there is no target block that contains label, then we are looking
1406  // at an incomplete AST. Handle this by not registering a successor.
1407  if (LI == LabelMap.end()) continue;
1408 
1409  addSuccessor(B, LI->second.block);
1410  }
1411 
1412  // Create an empty entry block that has no predecessors.
1413  cfg->setEntry(createBlock());
1414 
1415  if (BuildOpts.AddRichCXXConstructors)
1416  assert(ConstructionContextMap.empty() &&
1417  "Not all construction contexts were cleaned up!");
1418 
1419  return std::move(cfg);
1420 }
1421 
1422 /// createBlock - Used to lazily create blocks that are connected
1423 /// to the current (global) succcessor.
1424 CFGBlock *CFGBuilder::createBlock(bool add_successor) {
1425  CFGBlock *B = cfg->createBlock();
1426  if (add_successor && Succ)
1427  addSuccessor(B, Succ);
1428  return B;
1429 }
1430 
1431 /// createNoReturnBlock - Used to create a block is a 'noreturn' point in the
1432 /// CFG. It is *not* connected to the current (global) successor, and instead
1433 /// directly tied to the exit block in order to be reachable.
1434 CFGBlock *CFGBuilder::createNoReturnBlock() {
1435  CFGBlock *B = createBlock(false);
1436  B->setHasNoReturnElement();
1437  addSuccessor(B, &cfg->getExit(), Succ);
1438  return B;
1439 }
1440 
1441 /// addInitializer - Add C++ base or member initializer element to CFG.
1442 CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) {
1443  if (!BuildOpts.AddInitializers)
1444  return Block;
1445 
1446  bool HasTemporaries = false;
1447 
1448  // Destructors of temporaries in initialization expression should be called
1449  // after initialization finishes.
1450  Expr *Init = I->getInit();
1451  if (Init) {
1452  HasTemporaries = isa<ExprWithCleanups>(Init);
1453 
1454  if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
1455  // Generate destructors for temporaries in initialization expression.
1456  TempDtorContext Context;
1457  VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
1458  /*BindToTemporary=*/false, Context);
1459  }
1460  }
1461 
1462  autoCreateBlock();
1463  appendInitializer(Block, I);
1464 
1465  if (Init) {
1466  findConstructionContexts(
1467  ConstructionContextLayer::create(cfg->getBumpVectorContext(), I),
1468  Init);
1469 
1470  if (HasTemporaries) {
1471  // For expression with temporaries go directly to subexpression to omit
1472  // generating destructors for the second time.
1473  return Visit(cast<ExprWithCleanups>(Init)->getSubExpr());
1474  }
1475  if (BuildOpts.AddCXXDefaultInitExprInCtors) {
1476  if (CXXDefaultInitExpr *Default = dyn_cast<CXXDefaultInitExpr>(Init)) {
1477  // In general, appending the expression wrapped by a CXXDefaultInitExpr
1478  // may cause the same Expr to appear more than once in the CFG. Doing it
1479  // here is safe because there's only one initializer per field.
1480  autoCreateBlock();
1481  appendStmt(Block, Default);
1482  if (Stmt *Child = Default->getExpr())
1483  if (CFGBlock *R = Visit(Child))
1484  Block = R;
1485  return Block;
1486  }
1487  }
1488  return Visit(Init);
1489  }
1490 
1491  return Block;
1492 }
1493 
1494 /// Retrieve the type of the temporary object whose lifetime was
1495 /// extended by a local reference with the given initializer.
1497  const Expr *Init,
1498  bool *FoundMTE = nullptr) {
1499  while (true) {
1500  // Skip parentheses.
1501  Init = Init->IgnoreParens();
1502 
1503  // Skip through cleanups.
1504  if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Init)) {
1505  Init = EWC->getSubExpr();
1506  continue;
1507  }
1508 
1509  // Skip through the temporary-materialization expression.
1510  if (const MaterializeTemporaryExpr *MTE
1511  = dyn_cast<MaterializeTemporaryExpr>(Init)) {
1512  Init = MTE->GetTemporaryExpr();
1513  if (FoundMTE)
1514  *FoundMTE = true;
1515  continue;
1516  }
1517 
1518  // Skip derived-to-base and no-op casts.
1519  if (const CastExpr *CE = dyn_cast<CastExpr>(Init)) {
1520  if ((CE->getCastKind() == CK_DerivedToBase ||
1521  CE->getCastKind() == CK_UncheckedDerivedToBase ||
1522  CE->getCastKind() == CK_NoOp) &&
1523  Init->getType()->isRecordType()) {
1524  Init = CE->getSubExpr();
1525  continue;
1526  }
1527  }
1528 
1529  // Skip member accesses into rvalues.
1530  if (const MemberExpr *ME = dyn_cast<MemberExpr>(Init)) {
1531  if (!ME->isArrow() && ME->getBase()->isRValue()) {
1532  Init = ME->getBase();
1533  continue;
1534  }
1535  }
1536 
1537  break;
1538  }
1539 
1540  return Init->getType();
1541 }
1542 
1543 // TODO: Support adding LoopExit element to the CFG in case where the loop is
1544 // ended by ReturnStmt, GotoStmt or ThrowExpr.
1545 void CFGBuilder::addLoopExit(const Stmt *LoopStmt){
1546  if(!BuildOpts.AddLoopExit)
1547  return;
1548  autoCreateBlock();
1549  appendLoopExit(Block, LoopStmt);
1550 }
1551 
1552 void CFGBuilder::getDeclsWithEndedScope(LocalScope::const_iterator B,
1553  LocalScope::const_iterator E, Stmt *S) {
1554  if (!BuildOpts.AddScopes)
1555  return;
1556 
1557  if (B == E)
1558  return;
1559 
1560  // To go from B to E, one first goes up the scopes from B to P
1561  // then sideways in one scope from P to P' and then down
1562  // the scopes from P' to E.
1563  // The lifetime of all objects between B and P end.
1564  LocalScope::const_iterator P = B.shared_parent(E);
1565  int Dist = B.distance(P);
1566  if (Dist <= 0)
1567  return;
1568 
1569  for (LocalScope::const_iterator I = B; I != P; ++I)
1570  if (I.pointsToFirstDeclaredVar())
1571  DeclsWithEndedScope.insert(*I);
1572 }
1573 
1574 void CFGBuilder::addAutomaticObjHandling(LocalScope::const_iterator B,
1575  LocalScope::const_iterator E,
1576  Stmt *S) {
1577  getDeclsWithEndedScope(B, E, S);
1578  if (BuildOpts.AddScopes)
1579  addScopesEnd(B, E, S);
1580  if (BuildOpts.AddImplicitDtors)
1581  addAutomaticObjDtors(B, E, S);
1582  if (BuildOpts.AddLifetime)
1583  addLifetimeEnds(B, E, S);
1584 }
1585 
1586 /// Add to current block automatic objects that leave the scope.
1587 void CFGBuilder::addLifetimeEnds(LocalScope::const_iterator B,
1588  LocalScope::const_iterator E, Stmt *S) {
1589  if (!BuildOpts.AddLifetime)
1590  return;
1591 
1592  if (B == E)
1593  return;
1594 
1595  // To go from B to E, one first goes up the scopes from B to P
1596  // then sideways in one scope from P to P' and then down
1597  // the scopes from P' to E.
1598  // The lifetime of all objects between B and P end.
1599  LocalScope::const_iterator P = B.shared_parent(E);
1600  int dist = B.distance(P);
1601  if (dist <= 0)
1602  return;
1603 
1604  // We need to perform the scope leaving in reverse order
1605  SmallVector<VarDecl *, 10> DeclsTrivial;
1606  SmallVector<VarDecl *, 10> DeclsNonTrivial;
1607  DeclsTrivial.reserve(dist);
1608  DeclsNonTrivial.reserve(dist);
1609 
1610  for (LocalScope::const_iterator I = B; I != P; ++I)
1611  if (hasTrivialDestructor(*I))
1612  DeclsTrivial.push_back(*I);
1613  else
1614  DeclsNonTrivial.push_back(*I);
1615 
1616  autoCreateBlock();
1617  // object with trivial destructor end their lifetime last (when storage
1618  // duration ends)
1619  for (SmallVectorImpl<VarDecl *>::reverse_iterator I = DeclsTrivial.rbegin(),
1620  E = DeclsTrivial.rend();
1621  I != E; ++I)
1622  appendLifetimeEnds(Block, *I, S);
1623 
1625  I = DeclsNonTrivial.rbegin(),
1626  E = DeclsNonTrivial.rend();
1627  I != E; ++I)
1628  appendLifetimeEnds(Block, *I, S);
1629 }
1630 
1631 /// Add to current block markers for ending scopes.
1632 void CFGBuilder::addScopesEnd(LocalScope::const_iterator B,
1633  LocalScope::const_iterator E, Stmt *S) {
1634  // If implicit destructors are enabled, we'll add scope ends in
1635  // addAutomaticObjDtors.
1636  if (BuildOpts.AddImplicitDtors)
1637  return;
1638 
1639  autoCreateBlock();
1640 
1641  for (auto I = DeclsWithEndedScope.rbegin(), E = DeclsWithEndedScope.rend();
1642  I != E; ++I)
1643  appendScopeEnd(Block, *I, S);
1644 
1645  return;
1646 }
1647 
1648 /// addAutomaticObjDtors - Add to current block automatic objects destructors
1649 /// for objects in range of local scope positions. Use S as trigger statement
1650 /// for destructors.
1651 void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B,
1652  LocalScope::const_iterator E, Stmt *S) {
1653  if (!BuildOpts.AddImplicitDtors)
1654  return;
1655 
1656  if (B == E)
1657  return;
1658 
1659  // We need to append the destructors in reverse order, but any one of them
1660  // may be a no-return destructor which changes the CFG. As a result, buffer
1661  // this sequence up and replay them in reverse order when appending onto the
1662  // CFGBlock(s).
1664  Decls.reserve(B.distance(E));
1665  for (LocalScope::const_iterator I = B; I != E; ++I)
1666  Decls.push_back(*I);
1667 
1668  for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(),
1669  E = Decls.rend();
1670  I != E; ++I) {
1671  if (hasTrivialDestructor(*I)) {
1672  // If AddScopes is enabled and *I is a first variable in a scope, add a
1673  // ScopeEnd marker in a Block.
1674  if (BuildOpts.AddScopes && DeclsWithEndedScope.count(*I)) {
1675  autoCreateBlock();
1676  appendScopeEnd(Block, *I, S);
1677  }
1678  continue;
1679  }
1680  // If this destructor is marked as a no-return destructor, we need to
1681  // create a new block for the destructor which does not have as a successor
1682  // anything built thus far: control won't flow out of this block.
1683  QualType Ty = (*I)->getType();
1684  if (Ty->isReferenceType()) {
1685  Ty = getReferenceInitTemporaryType(*Context, (*I)->getInit());
1686  }
1687  Ty = Context->getBaseElementType(Ty);
1688 
1689  if (Ty->getAsCXXRecordDecl()->isAnyDestructorNoReturn())
1690  Block = createNoReturnBlock();
1691  else
1692  autoCreateBlock();
1693 
1694  // Add ScopeEnd just after automatic obj destructor.
1695  if (BuildOpts.AddScopes && DeclsWithEndedScope.count(*I))
1696  appendScopeEnd(Block, *I, S);
1697  appendAutomaticObjDtor(Block, *I, S);
1698  }
1699 }
1700 
1701 /// addImplicitDtorsForDestructor - Add implicit destructors generated for
1702 /// base and member objects in destructor.
1703 void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) {
1704  assert(BuildOpts.AddImplicitDtors &&
1705  "Can be called only when dtors should be added");
1706  const CXXRecordDecl *RD = DD->getParent();
1707 
1708  // At the end destroy virtual base objects.
1709  for (const auto &VI : RD->vbases()) {
1710  const CXXRecordDecl *CD = VI.getType()->getAsCXXRecordDecl();
1711  if (!CD->hasTrivialDestructor()) {
1712  autoCreateBlock();
1713  appendBaseDtor(Block, &VI);
1714  }
1715  }
1716 
1717  // Before virtual bases destroy direct base objects.
1718  for (const auto &BI : RD->bases()) {
1719  if (!BI.isVirtual()) {
1720  const CXXRecordDecl *CD = BI.getType()->getAsCXXRecordDecl();
1721  if (!CD->hasTrivialDestructor()) {
1722  autoCreateBlock();
1723  appendBaseDtor(Block, &BI);
1724  }
1725  }
1726  }
1727 
1728  // First destroy member objects.
1729  for (auto *FI : RD->fields()) {
1730  // Check for constant size array. Set type to array element type.
1731  QualType QT = FI->getType();
1732  if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
1733  if (AT->getSize() == 0)
1734  continue;
1735  QT = AT->getElementType();
1736  }
1737 
1738  if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
1739  if (!CD->hasTrivialDestructor()) {
1740  autoCreateBlock();
1741  appendMemberDtor(Block, FI);
1742  }
1743  }
1744 }
1745 
1746 /// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either
1747 /// way return valid LocalScope object.
1748 LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) {
1749  if (Scope)
1750  return Scope;
1751  llvm::BumpPtrAllocator &alloc = cfg->getAllocator();
1752  return new (alloc.Allocate<LocalScope>())
1753  LocalScope(BumpVectorContext(alloc), ScopePos);
1754 }
1755 
1756 /// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement
1757 /// that should create implicit scope (e.g. if/else substatements).
1758 void CFGBuilder::addLocalScopeForStmt(Stmt *S) {
1759  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1760  !BuildOpts.AddScopes)
1761  return;
1762 
1763  LocalScope *Scope = nullptr;
1764 
1765  // For compound statement we will be creating explicit scope.
1766  if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
1767  for (auto *BI : CS->body()) {
1768  Stmt *SI = BI->stripLabelLikeStatements();
1769  if (DeclStmt *DS = dyn_cast<DeclStmt>(SI))
1770  Scope = addLocalScopeForDeclStmt(DS, Scope);
1771  }
1772  return;
1773  }
1774 
1775  // For any other statement scope will be implicit and as such will be
1776  // interesting only for DeclStmt.
1777  if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements()))
1778  addLocalScopeForDeclStmt(DS);
1779 }
1780 
1781 /// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will
1782 /// reuse Scope if not NULL.
1783 LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS,
1784  LocalScope* Scope) {
1785  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1786  !BuildOpts.AddScopes)
1787  return Scope;
1788 
1789  for (auto *DI : DS->decls())
1790  if (VarDecl *VD = dyn_cast<VarDecl>(DI))
1791  Scope = addLocalScopeForVarDecl(VD, Scope);
1792  return Scope;
1793 }
1794 
1795 bool CFGBuilder::hasTrivialDestructor(VarDecl *VD) {
1796  // Check for const references bound to temporary. Set type to pointee.
1797  QualType QT = VD->getType();
1798  if (QT.getTypePtr()->isReferenceType()) {
1799  // Attempt to determine whether this declaration lifetime-extends a
1800  // temporary.
1801  //
1802  // FIXME: This is incorrect. Non-reference declarations can lifetime-extend
1803  // temporaries, and a single declaration can extend multiple temporaries.
1804  // We should look at the storage duration on each nested
1805  // MaterializeTemporaryExpr instead.
1806 
1807  const Expr *Init = VD->getInit();
1808  if (!Init)
1809  return true;
1810 
1811  // Lifetime-extending a temporary.
1812  bool FoundMTE = false;
1813  QT = getReferenceInitTemporaryType(*Context, Init, &FoundMTE);
1814  if (!FoundMTE)
1815  return true;
1816  }
1817 
1818  // Check for constant size array. Set type to array element type.
1819  while (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
1820  if (AT->getSize() == 0)
1821  return true;
1822  QT = AT->getElementType();
1823  }
1824 
1825  // Check if type is a C++ class with non-trivial destructor.
1826  if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
1827  return !CD->hasDefinition() || CD->hasTrivialDestructor();
1828  return true;
1829 }
1830 
1831 /// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will
1832 /// create add scope for automatic objects and temporary objects bound to
1833 /// const reference. Will reuse Scope if not NULL.
1834 LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD,
1835  LocalScope* Scope) {
1836  assert(!(BuildOpts.AddImplicitDtors && BuildOpts.AddLifetime) &&
1837  "AddImplicitDtors and AddLifetime cannot be used at the same time");
1838  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1839  !BuildOpts.AddScopes)
1840  return Scope;
1841 
1842  // Check if variable is local.
1843  switch (VD->getStorageClass()) {
1844  case SC_None:
1845  case SC_Auto:
1846  case SC_Register:
1847  break;
1848  default: return Scope;
1849  }
1850 
1851  if (BuildOpts.AddImplicitDtors) {
1852  if (!hasTrivialDestructor(VD) || BuildOpts.AddScopes) {
1853  // Add the variable to scope
1854  Scope = createOrReuseLocalScope(Scope);
1855  Scope->addVar(VD);
1856  ScopePos = Scope->begin();
1857  }
1858  return Scope;
1859  }
1860 
1861  assert(BuildOpts.AddLifetime);
1862  // Add the variable to scope
1863  Scope = createOrReuseLocalScope(Scope);
1864  Scope->addVar(VD);
1865  ScopePos = Scope->begin();
1866  return Scope;
1867 }
1868 
1869 /// addLocalScopeAndDtors - For given statement add local scope for it and
1870 /// add destructors that will cleanup the scope. Will reuse Scope if not NULL.
1871 void CFGBuilder::addLocalScopeAndDtors(Stmt *S) {
1872  LocalScope::const_iterator scopeBeginPos = ScopePos;
1873  addLocalScopeForStmt(S);
1874  addAutomaticObjHandling(ScopePos, scopeBeginPos, S);
1875 }
1876 
1877 /// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for
1878 /// variables with automatic storage duration to CFGBlock's elements vector.
1879 /// Elements will be prepended to physical beginning of the vector which
1880 /// happens to be logical end. Use blocks terminator as statement that specifies
1881 /// destructors call site.
1882 /// FIXME: This mechanism for adding automatic destructors doesn't handle
1883 /// no-return destructors properly.
1884 void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
1885  LocalScope::const_iterator B, LocalScope::const_iterator E) {
1886  if (!BuildOpts.AddImplicitDtors)
1887  return;
1888  BumpVectorContext &C = cfg->getBumpVectorContext();
1889  CFGBlock::iterator InsertPos
1890  = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C);
1891  for (LocalScope::const_iterator I = B; I != E; ++I)
1892  InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I,
1893  Blk->getTerminator());
1894 }
1895 
1896 /// prependAutomaticObjLifetimeWithTerminator - Prepend lifetime CFGElements for
1897 /// variables with automatic storage duration to CFGBlock's elements vector.
1898 /// Elements will be prepended to physical beginning of the vector which
1899 /// happens to be logical end. Use blocks terminator as statement that specifies
1900 /// where lifetime ends.
1901 void CFGBuilder::prependAutomaticObjLifetimeWithTerminator(
1902  CFGBlock *Blk, LocalScope::const_iterator B, LocalScope::const_iterator E) {
1903  if (!BuildOpts.AddLifetime)
1904  return;
1905  BumpVectorContext &C = cfg->getBumpVectorContext();
1906  CFGBlock::iterator InsertPos =
1907  Blk->beginLifetimeEndsInsert(Blk->end(), B.distance(E), C);
1908  for (LocalScope::const_iterator I = B; I != E; ++I)
1909  InsertPos = Blk->insertLifetimeEnds(InsertPos, *I, Blk->getTerminator());
1910 }
1911 
1912 /// prependAutomaticObjScopeEndWithTerminator - Prepend scope end CFGElements for
1913 /// variables with automatic storage duration to CFGBlock's elements vector.
1914 /// Elements will be prepended to physical beginning of the vector which
1915 /// happens to be logical end. Use blocks terminator as statement that specifies
1916 /// where scope ends.
1917 const VarDecl *
1918 CFGBuilder::prependAutomaticObjScopeEndWithTerminator(
1919  CFGBlock *Blk, LocalScope::const_iterator B, LocalScope::const_iterator E) {
1920  if (!BuildOpts.AddScopes)
1921  return nullptr;
1922  BumpVectorContext &C = cfg->getBumpVectorContext();
1923  CFGBlock::iterator InsertPos =
1924  Blk->beginScopeEndInsert(Blk->end(), 1, C);
1925  LocalScope::const_iterator PlaceToInsert = B;
1926  for (LocalScope::const_iterator I = B; I != E; ++I)
1927  PlaceToInsert = I;
1928  Blk->insertScopeEnd(InsertPos, *PlaceToInsert, Blk->getTerminator());
1929  return *PlaceToInsert;
1930 }
1931 
1932 /// Visit - Walk the subtree of a statement and add extra
1933 /// blocks for ternary operators, &&, and ||. We also process "," and
1934 /// DeclStmts (which may contain nested control-flow).
1935 CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) {
1936  if (!S) {
1937  badCFG = true;
1938  return nullptr;
1939  }
1940 
1941  if (Expr *E = dyn_cast<Expr>(S))
1942  S = E->IgnoreParens();
1943 
1944  switch (S->getStmtClass()) {
1945  default:
1946  return VisitStmt(S, asc);
1947 
1948  case Stmt::AddrLabelExprClass:
1949  return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc);
1950 
1951  case Stmt::BinaryConditionalOperatorClass:
1952  return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc);
1953 
1954  case Stmt::BinaryOperatorClass:
1955  return VisitBinaryOperator(cast<BinaryOperator>(S), asc);
1956 
1957  case Stmt::BlockExprClass:
1958  return VisitBlockExpr(cast<BlockExpr>(S), asc);
1959 
1960  case Stmt::BreakStmtClass:
1961  return VisitBreakStmt(cast<BreakStmt>(S));
1962 
1963  case Stmt::CallExprClass:
1964  case Stmt::CXXOperatorCallExprClass:
1965  case Stmt::CXXMemberCallExprClass:
1966  case Stmt::UserDefinedLiteralClass:
1967  return VisitCallExpr(cast<CallExpr>(S), asc);
1968 
1969  case Stmt::CaseStmtClass:
1970  return VisitCaseStmt(cast<CaseStmt>(S));
1971 
1972  case Stmt::ChooseExprClass:
1973  return VisitChooseExpr(cast<ChooseExpr>(S), asc);
1974 
1975  case Stmt::CompoundStmtClass:
1976  return VisitCompoundStmt(cast<CompoundStmt>(S));
1977 
1978  case Stmt::ConditionalOperatorClass:
1979  return VisitConditionalOperator(cast<ConditionalOperator>(S), asc);
1980 
1981  case Stmt::ContinueStmtClass:
1982  return VisitContinueStmt(cast<ContinueStmt>(S));
1983 
1984  case Stmt::CXXCatchStmtClass:
1985  return VisitCXXCatchStmt(cast<CXXCatchStmt>(S));
1986 
1987  case Stmt::ExprWithCleanupsClass:
1988  return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc);
1989 
1990  case Stmt::CXXDefaultArgExprClass:
1991  case Stmt::CXXDefaultInitExprClass:
1992  // FIXME: The expression inside a CXXDefaultArgExpr is owned by the
1993  // called function's declaration, not by the caller. If we simply add
1994  // this expression to the CFG, we could end up with the same Expr
1995  // appearing multiple times.
1996  // PR13385 / <rdar://problem/12156507>
1997  //
1998  // It's likewise possible for multiple CXXDefaultInitExprs for the same
1999  // expression to be used in the same function (through aggregate
2000  // initialization).
2001  return VisitStmt(S, asc);
2002 
2003  case Stmt::CXXBindTemporaryExprClass:
2004  return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc);
2005 
2006  case Stmt::CXXConstructExprClass:
2007  return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc);
2008 
2009  case Stmt::CXXNewExprClass:
2010  return VisitCXXNewExpr(cast<CXXNewExpr>(S), asc);
2011 
2012  case Stmt::CXXDeleteExprClass:
2013  return VisitCXXDeleteExpr(cast<CXXDeleteExpr>(S), asc);
2014 
2015  case Stmt::CXXFunctionalCastExprClass:
2016  return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc);
2017 
2018  case Stmt::CXXTemporaryObjectExprClass:
2019  return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc);
2020 
2021  case Stmt::CXXThrowExprClass:
2022  return VisitCXXThrowExpr(cast<CXXThrowExpr>(S));
2023 
2024  case Stmt::CXXTryStmtClass:
2025  return VisitCXXTryStmt(cast<CXXTryStmt>(S));
2026 
2027  case Stmt::CXXForRangeStmtClass:
2028  return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S));
2029 
2030  case Stmt::DeclStmtClass:
2031  return VisitDeclStmt(cast<DeclStmt>(S));
2032 
2033  case Stmt::DefaultStmtClass:
2034  return VisitDefaultStmt(cast<DefaultStmt>(S));
2035 
2036  case Stmt::DoStmtClass:
2037  return VisitDoStmt(cast<DoStmt>(S));
2038 
2039  case Stmt::ForStmtClass:
2040  return VisitForStmt(cast<ForStmt>(S));
2041 
2042  case Stmt::GotoStmtClass:
2043  return VisitGotoStmt(cast<GotoStmt>(S));
2044 
2045  case Stmt::IfStmtClass:
2046  return VisitIfStmt(cast<IfStmt>(S));
2047 
2048  case Stmt::ImplicitCastExprClass:
2049  return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc);
2050 
2051  case Stmt::IndirectGotoStmtClass:
2052  return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S));
2053 
2054  case Stmt::LabelStmtClass:
2055  return VisitLabelStmt(cast<LabelStmt>(S));
2056 
2057  case Stmt::LambdaExprClass:
2058  return VisitLambdaExpr(cast<LambdaExpr>(S), asc);
2059 
2060  case Stmt::MaterializeTemporaryExprClass:
2061  return VisitMaterializeTemporaryExpr(cast<MaterializeTemporaryExpr>(S),
2062  asc);
2063 
2064  case Stmt::MemberExprClass:
2065  return VisitMemberExpr(cast<MemberExpr>(S), asc);
2066 
2067  case Stmt::NullStmtClass:
2068  return Block;
2069 
2070  case Stmt::ObjCAtCatchStmtClass:
2071  return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S));
2072 
2073  case Stmt::ObjCAutoreleasePoolStmtClass:
2074  return VisitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(S));
2075 
2076  case Stmt::ObjCAtSynchronizedStmtClass:
2077  return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S));
2078 
2079  case Stmt::ObjCAtThrowStmtClass:
2080  return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S));
2081 
2082  case Stmt::ObjCAtTryStmtClass:
2083  return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S));
2084 
2085  case Stmt::ObjCForCollectionStmtClass:
2086  return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S));
2087 
2088  case Stmt::OpaqueValueExprClass:
2089  return Block;
2090 
2091  case Stmt::PseudoObjectExprClass:
2092  return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S));
2093 
2094  case Stmt::ReturnStmtClass:
2095  return VisitReturnStmt(cast<ReturnStmt>(S));
2096 
2097  case Stmt::SEHExceptStmtClass:
2098  return VisitSEHExceptStmt(cast<SEHExceptStmt>(S));
2099 
2100  case Stmt::SEHFinallyStmtClass:
2101  return VisitSEHFinallyStmt(cast<SEHFinallyStmt>(S));
2102 
2103  case Stmt::SEHLeaveStmtClass:
2104  return VisitSEHLeaveStmt(cast<SEHLeaveStmt>(S));
2105 
2106  case Stmt::SEHTryStmtClass:
2107  return VisitSEHTryStmt(cast<SEHTryStmt>(S));
2108 
2109  case Stmt::UnaryExprOrTypeTraitExprClass:
2110  return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S),
2111  asc);
2112 
2113  case Stmt::StmtExprClass:
2114  return VisitStmtExpr(cast<StmtExpr>(S), asc);
2115 
2116  case Stmt::SwitchStmtClass:
2117  return VisitSwitchStmt(cast<SwitchStmt>(S));
2118 
2119  case Stmt::UnaryOperatorClass:
2120  return VisitUnaryOperator(cast<UnaryOperator>(S), asc);
2121 
2122  case Stmt::WhileStmtClass:
2123  return VisitWhileStmt(cast<WhileStmt>(S));
2124  }
2125 }
2126 
2127 CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) {
2128  if (asc.alwaysAdd(*this, S)) {
2129  autoCreateBlock();
2130  appendStmt(Block, S);
2131  }
2132 
2133  return VisitChildren(S);
2134 }
2135 
2136 /// VisitChildren - Visit the children of a Stmt.
2137 CFGBlock *CFGBuilder::VisitChildren(Stmt *S) {
2138  CFGBlock *B = Block;
2139 
2140  // Visit the children in their reverse order so that they appear in
2141  // left-to-right (natural) order in the CFG.
2142  reverse_children RChildren(S);
2143  for (reverse_children::iterator I = RChildren.begin(), E = RChildren.end();
2144  I != E; ++I) {
2145  if (Stmt *Child = *I)
2146  if (CFGBlock *R = Visit(Child))
2147  B = R;
2148  }
2149  return B;
2150 }
2151 
2152 CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A,
2153  AddStmtChoice asc) {
2154  AddressTakenLabels.insert(A->getLabel());
2155 
2156  if (asc.alwaysAdd(*this, A)) {
2157  autoCreateBlock();
2158  appendStmt(Block, A);
2159  }
2160 
2161  return Block;
2162 }
2163 
2164 CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U,
2165  AddStmtChoice asc) {
2166  if (asc.alwaysAdd(*this, U)) {
2167  autoCreateBlock();
2168  appendStmt(Block, U);
2169  }
2170 
2171  return Visit(U->getSubExpr(), AddStmtChoice());
2172 }
2173 
2174 CFGBlock *CFGBuilder::VisitLogicalOperator(BinaryOperator *B) {
2175  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2176  appendStmt(ConfluenceBlock, B);
2177 
2178  if (badCFG)
2179  return nullptr;
2180 
2181  return VisitLogicalOperator(B, nullptr, ConfluenceBlock,
2182  ConfluenceBlock).first;
2183 }
2184 
2185 std::pair<CFGBlock*, CFGBlock*>
2186 CFGBuilder::VisitLogicalOperator(BinaryOperator *B,
2187  Stmt *Term,
2188  CFGBlock *TrueBlock,
2189  CFGBlock *FalseBlock) {
2190  // Introspect the RHS. If it is a nested logical operation, we recursively
2191  // build the CFG using this function. Otherwise, resort to default
2192  // CFG construction behavior.
2193  Expr *RHS = B->getRHS()->IgnoreParens();
2194  CFGBlock *RHSBlock, *ExitBlock;
2195 
2196  do {
2197  if (BinaryOperator *B_RHS = dyn_cast<BinaryOperator>(RHS))
2198  if (B_RHS->isLogicalOp()) {
2199  std::tie(RHSBlock, ExitBlock) =
2200  VisitLogicalOperator(B_RHS, Term, TrueBlock, FalseBlock);
2201  break;
2202  }
2203 
2204  // The RHS is not a nested logical operation. Don't push the terminator
2205  // down further, but instead visit RHS and construct the respective
2206  // pieces of the CFG, and link up the RHSBlock with the terminator
2207  // we have been provided.
2208  ExitBlock = RHSBlock = createBlock(false);
2209 
2210  // Even though KnownVal is only used in the else branch of the next
2211  // conditional, tryEvaluateBool performs additional checking on the
2212  // Expr, so it should be called unconditionally.
2213  TryResult KnownVal = tryEvaluateBool(RHS);
2214  if (!KnownVal.isKnown())
2215  KnownVal = tryEvaluateBool(B);
2216 
2217  if (!Term) {
2218  assert(TrueBlock == FalseBlock);
2219  addSuccessor(RHSBlock, TrueBlock);
2220  }
2221  else {
2222  RHSBlock->setTerminator(Term);
2223  addSuccessor(RHSBlock, TrueBlock, !KnownVal.isFalse());
2224  addSuccessor(RHSBlock, FalseBlock, !KnownVal.isTrue());
2225  }
2226 
2227  Block = RHSBlock;
2228  RHSBlock = addStmt(RHS);
2229  }
2230  while (false);
2231 
2232  if (badCFG)
2233  return std::make_pair(nullptr, nullptr);
2234 
2235  // Generate the blocks for evaluating the LHS.
2236  Expr *LHS = B->getLHS()->IgnoreParens();
2237 
2238  if (BinaryOperator *B_LHS = dyn_cast<BinaryOperator>(LHS))
2239  if (B_LHS->isLogicalOp()) {
2240  if (B->getOpcode() == BO_LOr)
2241  FalseBlock = RHSBlock;
2242  else
2243  TrueBlock = RHSBlock;
2244 
2245  // For the LHS, treat 'B' as the terminator that we want to sink
2246  // into the nested branch. The RHS always gets the top-most
2247  // terminator.
2248  return VisitLogicalOperator(B_LHS, B, TrueBlock, FalseBlock);
2249  }
2250 
2251  // Create the block evaluating the LHS.
2252  // This contains the '&&' or '||' as the terminator.
2253  CFGBlock *LHSBlock = createBlock(false);
2254  LHSBlock->setTerminator(B);
2255 
2256  Block = LHSBlock;
2257  CFGBlock *EntryLHSBlock = addStmt(LHS);
2258 
2259  if (badCFG)
2260  return std::make_pair(nullptr, nullptr);
2261 
2262  // See if this is a known constant.
2263  TryResult KnownVal = tryEvaluateBool(LHS);
2264 
2265  // Now link the LHSBlock with RHSBlock.
2266  if (B->getOpcode() == BO_LOr) {
2267  addSuccessor(LHSBlock, TrueBlock, !KnownVal.isFalse());
2268  addSuccessor(LHSBlock, RHSBlock, !KnownVal.isTrue());
2269  } else {
2270  assert(B->getOpcode() == BO_LAnd);
2271  addSuccessor(LHSBlock, RHSBlock, !KnownVal.isFalse());
2272  addSuccessor(LHSBlock, FalseBlock, !KnownVal.isTrue());
2273  }
2274 
2275  return std::make_pair(EntryLHSBlock, ExitBlock);
2276 }
2277 
2278 CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B,
2279  AddStmtChoice asc) {
2280  // && or ||
2281  if (B->isLogicalOp())
2282  return VisitLogicalOperator(B);
2283 
2284  if (B->getOpcode() == BO_Comma) { // ,
2285  autoCreateBlock();
2286  appendStmt(Block, B);
2287  addStmt(B->getRHS());
2288  return addStmt(B->getLHS());
2289  }
2290 
2291  if (B->isAssignmentOp()) {
2292  if (asc.alwaysAdd(*this, B)) {
2293  autoCreateBlock();
2294  appendStmt(Block, B);
2295  }
2296  Visit(B->getLHS());
2297  return Visit(B->getRHS());
2298  }
2299 
2300  if (asc.alwaysAdd(*this, B)) {
2301  autoCreateBlock();
2302  appendStmt(Block, B);
2303  }
2304 
2305  CFGBlock *RBlock = Visit(B->getRHS());
2306  CFGBlock *LBlock = Visit(B->getLHS());
2307  // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr
2308  // containing a DoStmt, and the LHS doesn't create a new block, then we should
2309  // return RBlock. Otherwise we'll incorrectly return NULL.
2310  return (LBlock ? LBlock : RBlock);
2311 }
2312 
2313 CFGBlock *CFGBuilder::VisitNoRecurse(Expr *E, AddStmtChoice asc) {
2314  if (asc.alwaysAdd(*this, E)) {
2315  autoCreateBlock();
2316  appendStmt(Block, E);
2317  }
2318  return Block;
2319 }
2320 
2321 CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) {
2322  // "break" is a control-flow statement. Thus we stop processing the current
2323  // block.
2324  if (badCFG)
2325  return nullptr;
2326 
2327  // Now create a new block that ends with the break statement.
2328  Block = createBlock(false);
2329  Block->setTerminator(B);
2330 
2331  // If there is no target for the break, then we are looking at an incomplete
2332  // AST. This means that the CFG cannot be constructed.
2333  if (BreakJumpTarget.block) {
2334  addAutomaticObjHandling(ScopePos, BreakJumpTarget.scopePosition, B);
2335  addSuccessor(Block, BreakJumpTarget.block);
2336  } else
2337  badCFG = true;
2338 
2339  return Block;
2340 }
2341 
2342 static bool CanThrow(Expr *E, ASTContext &Ctx) {
2343  QualType Ty = E->getType();
2344  if (Ty->isFunctionPointerType())
2345  Ty = Ty->getAs<PointerType>()->getPointeeType();
2346  else if (Ty->isBlockPointerType())
2347  Ty = Ty->getAs<BlockPointerType>()->getPointeeType();
2348 
2349  const FunctionType *FT = Ty->getAs<FunctionType>();
2350  if (FT) {
2351  if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT))
2352  if (!isUnresolvedExceptionSpec(Proto->getExceptionSpecType()) &&
2353  Proto->isNothrow())
2354  return false;
2355  }
2356  return true;
2357 }
2358 
2359 CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) {
2360  // Compute the callee type.
2361  QualType calleeType = C->getCallee()->getType();
2362  if (calleeType == Context->BoundMemberTy) {
2363  QualType boundType = Expr::findBoundMemberType(C->getCallee());
2364 
2365  // We should only get a null bound type if processing a dependent
2366  // CFG. Recover by assuming nothing.
2367  if (!boundType.isNull()) calleeType = boundType;
2368  }
2369 
2370  // FIXME: Once actually implemented, this construction context layer should
2371  // include the number of the argument as well.
2372  for (auto Arg: C->arguments()) {
2373  findConstructionContexts(
2374  ConstructionContextLayer::create(cfg->getBumpVectorContext(), C), Arg);
2375  }
2376 
2377  // If this is a call to a no-return function, this stops the block here.
2378  bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn();
2379 
2380  bool AddEHEdge = false;
2381 
2382  // Languages without exceptions are assumed to not throw.
2383  if (Context->getLangOpts().Exceptions) {
2384  if (BuildOpts.AddEHEdges)
2385  AddEHEdge = true;
2386  }
2387 
2388  // If this is a call to a builtin function, it might not actually evaluate
2389  // its arguments. Don't add them to the CFG if this is the case.
2390  bool OmitArguments = false;
2391 
2392  if (FunctionDecl *FD = C->getDirectCallee()) {
2393  if (FD->isNoReturn() || C->isBuiltinAssumeFalse(*Context))
2394  NoReturn = true;
2395  if (FD->hasAttr<NoThrowAttr>())
2396  AddEHEdge = false;
2397  if (FD->getBuiltinID() == Builtin::BI__builtin_object_size)
2398  OmitArguments = true;
2399  }
2400 
2401  if (!CanThrow(C->getCallee(), *Context))
2402  AddEHEdge = false;
2403 
2404  if (OmitArguments) {
2405  assert(!NoReturn && "noreturn calls with unevaluated args not implemented");
2406  assert(!AddEHEdge && "EH calls with unevaluated args not implemented");
2407  autoCreateBlock();
2408  appendStmt(Block, C);
2409  return Visit(C->getCallee());
2410  }
2411 
2412  if (!NoReturn && !AddEHEdge) {
2413  autoCreateBlock();
2414  appendCall(Block, C);
2415 
2416  return VisitChildren(C);
2417  }
2418 
2419  if (Block) {
2420  Succ = Block;
2421  if (badCFG)
2422  return nullptr;
2423  }
2424 
2425  if (NoReturn)
2426  Block = createNoReturnBlock();
2427  else
2428  Block = createBlock();
2429 
2430  appendCall(Block, C);
2431 
2432  if (AddEHEdge) {
2433  // Add exceptional edges.
2434  if (TryTerminatedBlock)
2435  addSuccessor(Block, TryTerminatedBlock);
2436  else
2437  addSuccessor(Block, &cfg->getExit());
2438  }
2439 
2440  return VisitChildren(C);
2441 }
2442 
2443 CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C,
2444  AddStmtChoice asc) {
2445  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2446  appendStmt(ConfluenceBlock, C);
2447  if (badCFG)
2448  return nullptr;
2449 
2450  AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2451  Succ = ConfluenceBlock;
2452  Block = nullptr;
2453  CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd);
2454  if (badCFG)
2455  return nullptr;
2456 
2457  Succ = ConfluenceBlock;
2458  Block = nullptr;
2459  CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd);
2460  if (badCFG)
2461  return nullptr;
2462 
2463  Block = createBlock(false);
2464  // See if this is a known constant.
2465  const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2466  addSuccessor(Block, KnownVal.isFalse() ? nullptr : LHSBlock);
2467  addSuccessor(Block, KnownVal.isTrue() ? nullptr : RHSBlock);
2468  Block->setTerminator(C);
2469  return addStmt(C->getCond());
2470 }
2471 
2472 CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) {
2473  LocalScope::const_iterator scopeBeginPos = ScopePos;
2474  addLocalScopeForStmt(C);
2475 
2476  if (!C->body_empty() && !isa<ReturnStmt>(*C->body_rbegin())) {
2477  // If the body ends with a ReturnStmt, the dtors will be added in
2478  // VisitReturnStmt.
2479  addAutomaticObjHandling(ScopePos, scopeBeginPos, C);
2480  }
2481 
2482  CFGBlock *LastBlock = Block;
2483 
2485  I != E; ++I ) {
2486  // If we hit a segment of code just containing ';' (NullStmts), we can
2487  // get a null block back. In such cases, just use the LastBlock
2488  if (CFGBlock *newBlock = addStmt(*I))
2489  LastBlock = newBlock;
2490 
2491  if (badCFG)
2492  return nullptr;
2493  }
2494 
2495  return LastBlock;
2496 }
2497 
2498 CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C,
2499  AddStmtChoice asc) {
2500  const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C);
2501  const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : nullptr);
2502 
2503  // Create the confluence block that will "merge" the results of the ternary
2504  // expression.
2505  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2506  appendStmt(ConfluenceBlock, C);
2507  if (badCFG)
2508  return nullptr;
2509 
2510  AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2511 
2512  // Create a block for the LHS expression if there is an LHS expression. A
2513  // GCC extension allows LHS to be NULL, causing the condition to be the
2514  // value that is returned instead.
2515  // e.g: x ?: y is shorthand for: x ? x : y;
2516  Succ = ConfluenceBlock;
2517  Block = nullptr;
2518  CFGBlock *LHSBlock = nullptr;
2519  const Expr *trueExpr = C->getTrueExpr();
2520  if (trueExpr != opaqueValue) {
2521  LHSBlock = Visit(C->getTrueExpr(), alwaysAdd);
2522  if (badCFG)
2523  return nullptr;
2524  Block = nullptr;
2525  }
2526  else
2527  LHSBlock = ConfluenceBlock;
2528 
2529  // Create the block for the RHS expression.
2530  Succ = ConfluenceBlock;
2531  CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd);
2532  if (badCFG)
2533  return nullptr;
2534 
2535  // If the condition is a logical '&&' or '||', build a more accurate CFG.
2536  if (BinaryOperator *Cond =
2537  dyn_cast<BinaryOperator>(C->getCond()->IgnoreParens()))
2538  if (Cond->isLogicalOp())
2539  return VisitLogicalOperator(Cond, C, LHSBlock, RHSBlock).first;
2540 
2541  // Create the block that will contain the condition.
2542  Block = createBlock(false);
2543 
2544  // See if this is a known constant.
2545  const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2546  addSuccessor(Block, LHSBlock, !KnownVal.isFalse());
2547  addSuccessor(Block, RHSBlock, !KnownVal.isTrue());
2548  Block->setTerminator(C);
2549  Expr *condExpr = C->getCond();
2550 
2551  if (opaqueValue) {
2552  // Run the condition expression if it's not trivially expressed in
2553  // terms of the opaque value (or if there is no opaque value).
2554  if (condExpr != opaqueValue)
2555  addStmt(condExpr);
2556 
2557  // Before that, run the common subexpression if there was one.
2558  // At least one of this or the above will be run.
2559  return addStmt(BCO->getCommon());
2560  }
2561 
2562  return addStmt(condExpr);
2563 }
2564 
2565 CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) {
2566  // Check if the Decl is for an __label__. If so, elide it from the
2567  // CFG entirely.
2568  if (isa<LabelDecl>(*DS->decl_begin()))
2569  return Block;
2570 
2571  // This case also handles static_asserts.
2572  if (DS->isSingleDecl())
2573  return VisitDeclSubExpr(DS);
2574 
2575  CFGBlock *B = nullptr;
2576 
2577  // Build an individual DeclStmt for each decl.
2579  E = DS->decl_rend();
2580  I != E; ++I) {
2581  // Get the alignment of the new DeclStmt, padding out to >=8 bytes.
2582  unsigned A = alignof(DeclStmt) < 8 ? 8 : alignof(DeclStmt);
2583 
2584  // Allocate the DeclStmt using the BumpPtrAllocator. It will get
2585  // automatically freed with the CFG.
2586  DeclGroupRef DG(*I);
2587  Decl *D = *I;
2588  void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A);
2589  DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D));
2590  cfg->addSyntheticDeclStmt(DSNew, DS);
2591 
2592  // Append the fake DeclStmt to block.
2593  B = VisitDeclSubExpr(DSNew);
2594  }
2595 
2596  return B;
2597 }
2598 
2599 /// VisitDeclSubExpr - Utility method to add block-level expressions for
2600 /// DeclStmts and initializers in them.
2601 CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) {
2602  assert(DS->isSingleDecl() && "Can handle single declarations only.");
2603  VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl());
2604 
2605  if (!VD) {
2606  // Of everything that can be declared in a DeclStmt, only VarDecls impact
2607  // runtime semantics.
2608  return Block;
2609  }
2610 
2611  bool HasTemporaries = false;
2612 
2613  // Guard static initializers under a branch.
2614  CFGBlock *blockAfterStaticInit = nullptr;
2615 
2616  if (BuildOpts.AddStaticInitBranches && VD->isStaticLocal()) {
2617  // For static variables, we need to create a branch to track
2618  // whether or not they are initialized.
2619  if (Block) {
2620  Succ = Block;
2621  Block = nullptr;
2622  if (badCFG)
2623  return nullptr;
2624  }
2625  blockAfterStaticInit = Succ;
2626  }
2627 
2628  // Destructors of temporaries in initialization expression should be called
2629  // after initialization finishes.
2630  Expr *Init = VD->getInit();
2631  if (Init) {
2632  HasTemporaries = isa<ExprWithCleanups>(Init);
2633 
2634  if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
2635  // Generate destructors for temporaries in initialization expression.
2636  TempDtorContext Context;
2637  VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
2638  /*BindToTemporary=*/false, Context);
2639  }
2640  }
2641 
2642  autoCreateBlock();
2643  appendStmt(Block, DS);
2644 
2645  findConstructionContexts(
2646  ConstructionContextLayer::create(cfg->getBumpVectorContext(), DS),
2647  Init);
2648 
2649  // Keep track of the last non-null block, as 'Block' can be nulled out
2650  // if the initializer expression is something like a 'while' in a
2651  // statement-expression.
2652  CFGBlock *LastBlock = Block;
2653 
2654  if (Init) {
2655  if (HasTemporaries) {
2656  // For expression with temporaries go directly to subexpression to omit
2657  // generating destructors for the second time.
2658  ExprWithCleanups *EC = cast<ExprWithCleanups>(Init);
2659  if (CFGBlock *newBlock = Visit(EC->getSubExpr()))
2660  LastBlock = newBlock;
2661  }
2662  else {
2663  if (CFGBlock *newBlock = Visit(Init))
2664  LastBlock = newBlock;
2665  }
2666  }
2667 
2668  // If the type of VD is a VLA, then we must process its size expressions.
2669  for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr());
2670  VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr())) {
2671  if (CFGBlock *newBlock = addStmt(VA->getSizeExpr()))
2672  LastBlock = newBlock;
2673  }
2674 
2675  maybeAddScopeBeginForVarDecl(Block, VD, DS);
2676 
2677  // Remove variable from local scope.
2678  if (ScopePos && VD == *ScopePos)
2679  ++ScopePos;
2680 
2681  CFGBlock *B = LastBlock;
2682  if (blockAfterStaticInit) {
2683  Succ = B;
2684  Block = createBlock(false);
2685  Block->setTerminator(DS);
2686  addSuccessor(Block, blockAfterStaticInit);
2687  addSuccessor(Block, B);
2688  B = Block;
2689  }
2690 
2691  return B;
2692 }
2693 
2694 CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) {
2695  // We may see an if statement in the middle of a basic block, or it may be the
2696  // first statement we are processing. In either case, we create a new basic
2697  // block. First, we create the blocks for the then...else statements, and
2698  // then we create the block containing the if statement. If we were in the
2699  // middle of a block, we stop processing that block. That block is then the
2700  // implicit successor for the "then" and "else" clauses.
2701 
2702  // Save local scope position because in case of condition variable ScopePos
2703  // won't be restored when traversing AST.
2704  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2705 
2706  // Create local scope for C++17 if init-stmt if one exists.
2707  if (Stmt *Init = I->getInit())
2708  addLocalScopeForStmt(Init);
2709 
2710  // Create local scope for possible condition variable.
2711  // Store scope position. Add implicit destructor.
2712  if (VarDecl *VD = I->getConditionVariable())
2713  addLocalScopeForVarDecl(VD);
2714 
2715  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), I);
2716 
2717  // The block we were processing is now finished. Make it the successor
2718  // block.
2719  if (Block) {
2720  Succ = Block;
2721  if (badCFG)
2722  return nullptr;
2723  }
2724 
2725  // Process the false branch.
2726  CFGBlock *ElseBlock = Succ;
2727 
2728  if (Stmt *Else = I->getElse()) {
2729  SaveAndRestore<CFGBlock*> sv(Succ);
2730 
2731  // NULL out Block so that the recursive call to Visit will
2732  // create a new basic block.
2733  Block = nullptr;
2734 
2735  // If branch is not a compound statement create implicit scope
2736  // and add destructors.
2737  if (!isa<CompoundStmt>(Else))
2738  addLocalScopeAndDtors(Else);
2739 
2740  ElseBlock = addStmt(Else);
2741 
2742  if (!ElseBlock) // Can occur when the Else body has all NullStmts.
2743  ElseBlock = sv.get();
2744  else if (Block) {
2745  if (badCFG)
2746  return nullptr;
2747  }
2748  }
2749 
2750  // Process the true branch.
2751  CFGBlock *ThenBlock;
2752  {
2753  Stmt *Then = I->getThen();
2754  assert(Then);
2755  SaveAndRestore<CFGBlock*> sv(Succ);
2756  Block = nullptr;
2757 
2758  // If branch is not a compound statement create implicit scope
2759  // and add destructors.
2760  if (!isa<CompoundStmt>(Then))
2761  addLocalScopeAndDtors(Then);
2762 
2763  ThenBlock = addStmt(Then);
2764 
2765  if (!ThenBlock) {
2766  // We can reach here if the "then" body has all NullStmts.
2767  // Create an empty block so we can distinguish between true and false
2768  // branches in path-sensitive analyses.
2769  ThenBlock = createBlock(false);
2770  addSuccessor(ThenBlock, sv.get());
2771  } else if (Block) {
2772  if (badCFG)
2773  return nullptr;
2774  }
2775  }
2776 
2777  // Specially handle "if (expr1 || ...)" and "if (expr1 && ...)" by
2778  // having these handle the actual control-flow jump. Note that
2779  // if we introduce a condition variable, e.g. "if (int x = exp1 || exp2)"
2780  // we resort to the old control-flow behavior. This special handling
2781  // removes infeasible paths from the control-flow graph by having the
2782  // control-flow transfer of '&&' or '||' go directly into the then/else
2783  // blocks directly.
2784  BinaryOperator *Cond =
2786  ? nullptr
2787  : dyn_cast<BinaryOperator>(I->getCond()->IgnoreParens());
2788  CFGBlock *LastBlock;
2789  if (Cond && Cond->isLogicalOp())
2790  LastBlock = VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first;
2791  else {
2792  // Now create a new block containing the if statement.
2793  Block = createBlock(false);
2794 
2795  // Set the terminator of the new block to the If statement.
2796  Block->setTerminator(I);
2797 
2798  // See if this is a known constant.
2799  const TryResult &KnownVal = tryEvaluateBool(I->getCond());
2800 
2801  // Add the successors. If we know that specific branches are
2802  // unreachable, inform addSuccessor() of that knowledge.
2803  addSuccessor(Block, ThenBlock, /* isReachable = */ !KnownVal.isFalse());
2804  addSuccessor(Block, ElseBlock, /* isReachable = */ !KnownVal.isTrue());
2805 
2806  // Add the condition as the last statement in the new block. This may
2807  // create new blocks as the condition may contain control-flow. Any newly
2808  // created blocks will be pointed to be "Block".
2809  LastBlock = addStmt(I->getCond());
2810 
2811  // If the IfStmt contains a condition variable, add it and its
2812  // initializer to the CFG.
2813  if (const DeclStmt* DS = I->getConditionVariableDeclStmt()) {
2814  autoCreateBlock();
2815  LastBlock = addStmt(const_cast<DeclStmt *>(DS));
2816  }
2817  }
2818 
2819  // Finally, if the IfStmt contains a C++17 init-stmt, add it to the CFG.
2820  if (Stmt *Init = I->getInit()) {
2821  autoCreateBlock();
2822  LastBlock = addStmt(Init);
2823  }
2824 
2825  return LastBlock;
2826 }
2827 
2828 CFGBlock *CFGBuilder::VisitReturnStmt(ReturnStmt *R) {
2829  // If we were in the middle of a block we stop processing that block.
2830  //
2831  // NOTE: If a "return" appears in the middle of a block, this means that the
2832  // code afterwards is DEAD (unreachable). We still keep a basic block
2833  // for that code; a simple "mark-and-sweep" from the entry block will be
2834  // able to report such dead blocks.
2835 
2836  // Create the new block.
2837  Block = createBlock(false);
2838 
2839  addAutomaticObjHandling(ScopePos, LocalScope::const_iterator(), R);
2840 
2841  findConstructionContexts(
2842  ConstructionContextLayer::create(cfg->getBumpVectorContext(), R),
2843  R->getRetValue());
2844 
2845  // If the one of the destructors does not return, we already have the Exit
2846  // block as a successor.
2847  if (!Block->hasNoReturnElement())
2848  addSuccessor(Block, &cfg->getExit());
2849 
2850  // Add the return statement to the block. This may create new blocks if R
2851  // contains control-flow (short-circuit operations).
2852  return VisitStmt(R, AddStmtChoice::AlwaysAdd);
2853 }
2854 
2855 CFGBlock *CFGBuilder::VisitSEHExceptStmt(SEHExceptStmt *ES) {
2856  // SEHExceptStmt are treated like labels, so they are the first statement in a
2857  // block.
2858 
2859  // Save local scope position because in case of exception variable ScopePos
2860  // won't be restored when traversing AST.
2861  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2862 
2863  addStmt(ES->getBlock());
2864  CFGBlock *SEHExceptBlock = Block;
2865  if (!SEHExceptBlock)
2866  SEHExceptBlock = createBlock();
2867 
2868  appendStmt(SEHExceptBlock, ES);
2869 
2870  // Also add the SEHExceptBlock as a label, like with regular labels.
2871  SEHExceptBlock->setLabel(ES);
2872 
2873  // Bail out if the CFG is bad.
2874  if (badCFG)
2875  return nullptr;
2876 
2877  // We set Block to NULL to allow lazy creation of a new block (if necessary).
2878  Block = nullptr;
2879 
2880  return SEHExceptBlock;
2881 }
2882 
2883 CFGBlock *CFGBuilder::VisitSEHFinallyStmt(SEHFinallyStmt *FS) {
2884  return VisitCompoundStmt(FS->getBlock());
2885 }
2886 
2887 CFGBlock *CFGBuilder::VisitSEHLeaveStmt(SEHLeaveStmt *LS) {
2888  // "__leave" is a control-flow statement. Thus we stop processing the current
2889  // block.
2890  if (badCFG)
2891  return nullptr;
2892 
2893  // Now create a new block that ends with the __leave statement.
2894  Block = createBlock(false);
2895  Block->setTerminator(LS);
2896 
2897  // If there is no target for the __leave, then we are looking at an incomplete
2898  // AST. This means that the CFG cannot be constructed.
2899  if (SEHLeaveJumpTarget.block) {
2900  addAutomaticObjHandling(ScopePos, SEHLeaveJumpTarget.scopePosition, LS);
2901  addSuccessor(Block, SEHLeaveJumpTarget.block);
2902  } else
2903  badCFG = true;
2904 
2905  return Block;
2906 }
2907 
2908 CFGBlock *CFGBuilder::VisitSEHTryStmt(SEHTryStmt *Terminator) {
2909  // "__try"/"__except"/"__finally" is a control-flow statement. Thus we stop
2910  // processing the current block.
2911  CFGBlock *SEHTrySuccessor = nullptr;
2912 
2913  if (Block) {
2914  if (badCFG)
2915  return nullptr;
2916  SEHTrySuccessor = Block;
2917  } else SEHTrySuccessor = Succ;
2918 
2919  // FIXME: Implement __finally support.
2920  if (Terminator->getFinallyHandler())
2921  return NYS();
2922 
2923  CFGBlock *PrevSEHTryTerminatedBlock = TryTerminatedBlock;
2924 
2925  // Create a new block that will contain the __try statement.
2926  CFGBlock *NewTryTerminatedBlock = createBlock(false);
2927 
2928  // Add the terminator in the __try block.
2929  NewTryTerminatedBlock->setTerminator(Terminator);
2930 
2931  if (SEHExceptStmt *Except = Terminator->getExceptHandler()) {
2932  // The code after the try is the implicit successor if there's an __except.
2933  Succ = SEHTrySuccessor;
2934  Block = nullptr;
2935  CFGBlock *ExceptBlock = VisitSEHExceptStmt(Except);
2936  if (!ExceptBlock)
2937  return nullptr;
2938  // Add this block to the list of successors for the block with the try
2939  // statement.
2940  addSuccessor(NewTryTerminatedBlock, ExceptBlock);
2941  }
2942  if (PrevSEHTryTerminatedBlock)
2943  addSuccessor(NewTryTerminatedBlock, PrevSEHTryTerminatedBlock);
2944  else
2945  addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
2946 
2947  // The code after the try is the implicit successor.
2948  Succ = SEHTrySuccessor;
2949 
2950  // Save the current "__try" context.
2951  SaveAndRestore<CFGBlock *> save_try(TryTerminatedBlock,
2952  NewTryTerminatedBlock);
2953  cfg->addTryDispatchBlock(TryTerminatedBlock);
2954 
2955  // Save the current value for the __leave target.
2956  // All __leaves should go to the code following the __try
2957  // (FIXME: or if the __try has a __finally, to the __finally.)
2958  SaveAndRestore<JumpTarget> save_break(SEHLeaveJumpTarget);
2959  SEHLeaveJumpTarget = JumpTarget(SEHTrySuccessor, ScopePos);
2960 
2961  assert(Terminator->getTryBlock() && "__try must contain a non-NULL body");
2962  Block = nullptr;
2963  return addStmt(Terminator->getTryBlock());
2964 }
2965 
2966 CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) {
2967  // Get the block of the labeled statement. Add it to our map.
2968  addStmt(L->getSubStmt());
2969  CFGBlock *LabelBlock = Block;
2970 
2971  if (!LabelBlock) // This can happen when the body is empty, i.e.
2972  LabelBlock = createBlock(); // scopes that only contains NullStmts.
2973 
2974  assert(LabelMap.find(L->getDecl()) == LabelMap.end() &&
2975  "label already in map");
2976  LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos);
2977 
2978  // Labels partition blocks, so this is the end of the basic block we were
2979  // processing (L is the block's label). Because this is label (and we have
2980  // already processed the substatement) there is no extra control-flow to worry
2981  // about.
2982  LabelBlock->setLabel(L);
2983  if (badCFG)
2984  return nullptr;
2985 
2986  // We set Block to NULL to allow lazy creation of a new block (if necessary);
2987  Block = nullptr;
2988 
2989  // This block is now the implicit successor of other blocks.
2990  Succ = LabelBlock;
2991 
2992  return LabelBlock;
2993 }
2994 
2995 CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) {
2996  CFGBlock *LastBlock = VisitNoRecurse(E, asc);
2997  for (const BlockDecl::Capture &CI : E->getBlockDecl()->captures()) {
2998  if (Expr *CopyExpr = CI.getCopyExpr()) {
2999  CFGBlock *Tmp = Visit(CopyExpr);
3000  if (Tmp)
3001  LastBlock = Tmp;
3002  }
3003  }
3004  return LastBlock;
3005 }
3006 
3007 CFGBlock *CFGBuilder::VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc) {
3008  CFGBlock *LastBlock = VisitNoRecurse(E, asc);
3010  et = E->capture_init_end(); it != et; ++it) {
3011  if (Expr *Init = *it) {
3012  CFGBlock *Tmp = Visit(Init);
3013  if (Tmp)
3014  LastBlock = Tmp;
3015  }
3016  }
3017  return LastBlock;
3018 }
3019 
3020 CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) {
3021  // Goto is a control-flow statement. Thus we stop processing the current
3022  // block and create a new one.
3023 
3024  Block = createBlock(false);
3025  Block->setTerminator(G);
3026 
3027  // If we already know the mapping to the label block add the successor now.
3028  LabelMapTy::iterator I = LabelMap.find(G->getLabel());
3029 
3030  if (I == LabelMap.end())
3031  // We will need to backpatch this block later.
3032  BackpatchBlocks.push_back(JumpSource(Block, ScopePos));
3033  else {
3034  JumpTarget JT = I->second;
3035  addAutomaticObjHandling(ScopePos, JT.scopePosition, G);
3036  addSuccessor(Block, JT.block);
3037  }
3038 
3039  return Block;
3040 }
3041 
3042 CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) {
3043  CFGBlock *LoopSuccessor = nullptr;
3044 
3045  // Save local scope position because in case of condition variable ScopePos
3046  // won't be restored when traversing AST.
3047  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3048 
3049  // Create local scope for init statement and possible condition variable.
3050  // Add destructor for init statement and condition variable.
3051  // Store scope position for continue statement.
3052  if (Stmt *Init = F->getInit())
3053  addLocalScopeForStmt(Init);
3054  LocalScope::const_iterator LoopBeginScopePos = ScopePos;
3055 
3056  if (VarDecl *VD = F->getConditionVariable())
3057  addLocalScopeForVarDecl(VD);
3058  LocalScope::const_iterator ContinueScopePos = ScopePos;
3059 
3060  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), F);
3061 
3062  addLoopExit(F);
3063 
3064  // "for" is a control-flow statement. Thus we stop processing the current
3065  // block.
3066  if (Block) {
3067  if (badCFG)
3068  return nullptr;
3069  LoopSuccessor = Block;
3070  } else
3071  LoopSuccessor = Succ;
3072 
3073  // Save the current value for the break targets.
3074  // All breaks should go to the code following the loop.
3075  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3076  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3077 
3078  CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
3079 
3080  // Now create the loop body.
3081  {
3082  assert(F->getBody());
3083 
3084  // Save the current values for Block, Succ, continue and break targets.
3085  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3086  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
3087 
3088  // Create an empty block to represent the transition block for looping back
3089  // to the head of the loop. If we have increment code, it will
3090  // go in this block as well.
3091  Block = Succ = TransitionBlock = createBlock(false);
3092  TransitionBlock->setLoopTarget(F);
3093 
3094  if (Stmt *I = F->getInc()) {
3095  // Generate increment code in its own basic block. This is the target of
3096  // continue statements.
3097  Succ = addStmt(I);
3098  }
3099 
3100  // Finish up the increment (or empty) block if it hasn't been already.
3101  if (Block) {
3102  assert(Block == Succ);
3103  if (badCFG)
3104  return nullptr;
3105  Block = nullptr;
3106  }
3107 
3108  // The starting block for the loop increment is the block that should
3109  // represent the 'loop target' for looping back to the start of the loop.
3110  ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
3111  ContinueJumpTarget.block->setLoopTarget(F);
3112 
3113  // Loop body should end with destructor of Condition variable (if any).
3114  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, F);
3115 
3116  // If body is not a compound statement create implicit scope
3117  // and add destructors.
3118  if (!isa<CompoundStmt>(F->getBody()))
3119  addLocalScopeAndDtors(F->getBody());
3120 
3121  // Now populate the body block, and in the process create new blocks as we
3122  // walk the body of the loop.
3123  BodyBlock = addStmt(F->getBody());
3124 
3125  if (!BodyBlock) {
3126  // In the case of "for (...;...;...);" we can have a null BodyBlock.
3127  // Use the continue jump target as the proxy for the body.
3128  BodyBlock = ContinueJumpTarget.block;
3129  }
3130  else if (badCFG)
3131  return nullptr;
3132  }
3133 
3134  // Because of short-circuit evaluation, the condition of the loop can span
3135  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3136  // evaluate the condition.
3137  CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
3138 
3139  do {
3140  Expr *C = F->getCond();
3141  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3142 
3143  // Specially handle logical operators, which have a slightly
3144  // more optimal CFG representation.
3145  if (BinaryOperator *Cond =
3146  dyn_cast_or_null<BinaryOperator>(C ? C->IgnoreParens() : nullptr))
3147  if (Cond->isLogicalOp()) {
3148  std::tie(EntryConditionBlock, ExitConditionBlock) =
3149  VisitLogicalOperator(Cond, F, BodyBlock, LoopSuccessor);
3150  break;
3151  }
3152 
3153  // The default case when not handling logical operators.
3154  EntryConditionBlock = ExitConditionBlock = createBlock(false);
3155  ExitConditionBlock->setTerminator(F);
3156 
3157  // See if this is a known constant.
3158  TryResult KnownVal(true);
3159 
3160  if (C) {
3161  // Now add the actual condition to the condition block.
3162  // Because the condition itself may contain control-flow, new blocks may
3163  // be created. Thus we update "Succ" after adding the condition.
3164  Block = ExitConditionBlock;
3165  EntryConditionBlock = addStmt(C);
3166 
3167  // If this block contains a condition variable, add both the condition
3168  // variable and initializer to the CFG.
3169  if (VarDecl *VD = F->getConditionVariable()) {
3170  if (Expr *Init = VD->getInit()) {
3171  autoCreateBlock();
3172  const DeclStmt *DS = F->getConditionVariableDeclStmt();
3173  assert(DS->isSingleDecl());
3174  findConstructionContexts(
3175  ConstructionContextLayer::create(cfg->getBumpVectorContext(),
3176  const_cast<DeclStmt *>(DS)),
3177  Init);
3178  appendStmt(Block, DS);
3179  EntryConditionBlock = addStmt(Init);
3180  assert(Block == EntryConditionBlock);
3181  maybeAddScopeBeginForVarDecl(EntryConditionBlock, VD, C);
3182  }
3183  }
3184 
3185  if (Block && badCFG)
3186  return nullptr;
3187 
3188  KnownVal = tryEvaluateBool(C);
3189  }
3190 
3191  // Add the loop body entry as a successor to the condition.
3192  addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
3193  // Link up the condition block with the code that follows the loop. (the
3194  // false branch).
3195  addSuccessor(ExitConditionBlock,
3196  KnownVal.isTrue() ? nullptr : LoopSuccessor);
3197  } while (false);
3198 
3199  // Link up the loop-back block to the entry condition block.
3200  addSuccessor(TransitionBlock, EntryConditionBlock);
3201 
3202  // The condition block is the implicit successor for any code above the loop.
3203  Succ = EntryConditionBlock;
3204 
3205  // If the loop contains initialization, create a new block for those
3206  // statements. This block can also contain statements that precede the loop.
3207  if (Stmt *I = F->getInit()) {
3208  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3209  ScopePos = LoopBeginScopePos;
3210  Block = createBlock();
3211  return addStmt(I);
3212  }
3213 
3214  // There is no loop initialization. We are thus basically a while loop.
3215  // NULL out Block to force lazy block construction.
3216  Block = nullptr;
3217  Succ = EntryConditionBlock;
3218  return EntryConditionBlock;
3219 }
3220 
3221 CFGBlock *
3222 CFGBuilder::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *MTE,
3223  AddStmtChoice asc) {
3224  findConstructionContexts(
3225  ConstructionContextLayer::create(cfg->getBumpVectorContext(), MTE),
3226  MTE->getTemporary());
3227 
3228  return VisitStmt(MTE, asc);
3229 }
3230 
3231 CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) {
3232  if (asc.alwaysAdd(*this, M)) {
3233  autoCreateBlock();
3234  appendStmt(Block, M);
3235  }
3236  return Visit(M->getBase());
3237 }
3238 
3239 CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) {
3240  // Objective-C fast enumeration 'for' statements:
3241  // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC
3242  //
3243  // for ( Type newVariable in collection_expression ) { statements }
3244  //
3245  // becomes:
3246  //
3247  // prologue:
3248  // 1. collection_expression
3249  // T. jump to loop_entry
3250  // loop_entry:
3251  // 1. side-effects of element expression
3252  // 1. ObjCForCollectionStmt [performs binding to newVariable]
3253  // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil]
3254  // TB:
3255  // statements
3256  // T. jump to loop_entry
3257  // FB:
3258  // what comes after
3259  //
3260  // and
3261  //
3262  // Type existingItem;
3263  // for ( existingItem in expression ) { statements }
3264  //
3265  // becomes:
3266  //
3267  // the same with newVariable replaced with existingItem; the binding works
3268  // the same except that for one ObjCForCollectionStmt::getElement() returns
3269  // a DeclStmt and the other returns a DeclRefExpr.
3270 
3271  CFGBlock *LoopSuccessor = nullptr;
3272 
3273  if (Block) {
3274  if (badCFG)
3275  return nullptr;
3276  LoopSuccessor = Block;
3277  Block = nullptr;
3278  } else
3279  LoopSuccessor = Succ;
3280 
3281  // Build the condition blocks.
3282  CFGBlock *ExitConditionBlock = createBlock(false);
3283 
3284  // Set the terminator for the "exit" condition block.
3285  ExitConditionBlock->setTerminator(S);
3286 
3287  // The last statement in the block should be the ObjCForCollectionStmt, which
3288  // performs the actual binding to 'element' and determines if there are any
3289  // more items in the collection.
3290  appendStmt(ExitConditionBlock, S);
3291  Block = ExitConditionBlock;
3292 
3293  // Walk the 'element' expression to see if there are any side-effects. We
3294  // generate new blocks as necessary. We DON'T add the statement by default to
3295  // the CFG unless it contains control-flow.
3296  CFGBlock *EntryConditionBlock = Visit(S->getElement(),
3297  AddStmtChoice::NotAlwaysAdd);
3298  if (Block) {
3299  if (badCFG)
3300  return nullptr;
3301  Block = nullptr;
3302  }
3303 
3304  // The condition block is the implicit successor for the loop body as well as
3305  // any code above the loop.
3306  Succ = EntryConditionBlock;
3307 
3308  // Now create the true branch.
3309  {
3310  // Save the current values for Succ, continue and break targets.
3311  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3312  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3313  save_break(BreakJumpTarget);
3314 
3315  // Add an intermediate block between the BodyBlock and the
3316  // EntryConditionBlock to represent the "loop back" transition, for looping
3317  // back to the head of the loop.
3318  CFGBlock *LoopBackBlock = nullptr;
3319  Succ = LoopBackBlock = createBlock();
3320  LoopBackBlock->setLoopTarget(S);
3321 
3322  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3323  ContinueJumpTarget = JumpTarget(Succ, ScopePos);
3324 
3325  CFGBlock *BodyBlock = addStmt(S->getBody());
3326 
3327  if (!BodyBlock)
3328  BodyBlock = ContinueJumpTarget.block; // can happen for "for (X in Y) ;"
3329  else if (Block) {
3330  if (badCFG)
3331  return nullptr;
3332  }
3333 
3334  // This new body block is a successor to our "exit" condition block.
3335  addSuccessor(ExitConditionBlock, BodyBlock);
3336  }
3337 
3338  // Link up the condition block with the code that follows the loop.
3339  // (the false branch).
3340  addSuccessor(ExitConditionBlock, LoopSuccessor);
3341 
3342  // Now create a prologue block to contain the collection expression.
3343  Block = createBlock();
3344  return addStmt(S->getCollection());
3345 }
3346 
3347 CFGBlock *CFGBuilder::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) {
3348  // Inline the body.
3349  return addStmt(S->getSubStmt());
3350  // TODO: consider adding cleanups for the end of @autoreleasepool scope.
3351 }
3352 
3353 CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) {
3354  // FIXME: Add locking 'primitives' to CFG for @synchronized.
3355 
3356  // Inline the body.
3357  CFGBlock *SyncBlock = addStmt(S->getSynchBody());
3358 
3359  // The sync body starts its own basic block. This makes it a little easier
3360  // for diagnostic clients.
3361  if (SyncBlock) {
3362  if (badCFG)
3363  return nullptr;
3364 
3365  Block = nullptr;
3366  Succ = SyncBlock;
3367  }
3368 
3369  // Add the @synchronized to the CFG.
3370  autoCreateBlock();
3371  appendStmt(Block, S);
3372 
3373  // Inline the sync expression.
3374  return addStmt(S->getSynchExpr());
3375 }
3376 
3377 CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) {
3378  // FIXME
3379  return NYS();
3380 }
3381 
3382 CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) {
3383  autoCreateBlock();
3384 
3385  // Add the PseudoObject as the last thing.
3386  appendStmt(Block, E);
3387 
3388  CFGBlock *lastBlock = Block;
3389 
3390  // Before that, evaluate all of the semantics in order. In
3391  // CFG-land, that means appending them in reverse order.
3392  for (unsigned i = E->getNumSemanticExprs(); i != 0; ) {
3393  Expr *Semantic = E->getSemanticExpr(--i);
3394 
3395  // If the semantic is an opaque value, we're being asked to bind
3396  // it to its source expression.
3397  if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
3398  Semantic = OVE->getSourceExpr();
3399 
3400  if (CFGBlock *B = Visit(Semantic))
3401  lastBlock = B;
3402  }
3403 
3404  return lastBlock;
3405 }
3406 
3407 CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) {
3408  CFGBlock *LoopSuccessor = nullptr;
3409 
3410  // Save local scope position because in case of condition variable ScopePos
3411  // won't be restored when traversing AST.
3412  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3413 
3414  // Create local scope for possible condition variable.
3415  // Store scope position for continue statement.
3416  LocalScope::const_iterator LoopBeginScopePos = ScopePos;
3417  if (VarDecl *VD = W->getConditionVariable()) {
3418  addLocalScopeForVarDecl(VD);
3419  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3420  }
3421  addLoopExit(W);
3422 
3423  // "while" is a control-flow statement. Thus we stop processing the current
3424  // block.
3425  if (Block) {
3426  if (badCFG)
3427  return nullptr;
3428  LoopSuccessor = Block;
3429  Block = nullptr;
3430  } else {
3431  LoopSuccessor = Succ;
3432  }
3433 
3434  CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
3435 
3436  // Process the loop body.
3437  {
3438  assert(W->getBody());
3439 
3440  // Save the current values for Block, Succ, continue and break targets.
3441  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3442  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3443  save_break(BreakJumpTarget);
3444 
3445  // Create an empty block to represent the transition block for looping back
3446  // to the head of the loop.
3447  Succ = TransitionBlock = createBlock(false);
3448  TransitionBlock->setLoopTarget(W);
3449  ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos);
3450 
3451  // All breaks should go to the code following the loop.
3452  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3453 
3454  // Loop body should end with destructor of Condition variable (if any).
3455  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3456 
3457  // If body is not a compound statement create implicit scope
3458  // and add destructors.
3459  if (!isa<CompoundStmt>(W->getBody()))
3460  addLocalScopeAndDtors(W->getBody());
3461 
3462  // Create the body. The returned block is the entry to the loop body.
3463  BodyBlock = addStmt(W->getBody());
3464 
3465  if (!BodyBlock)
3466  BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;"
3467  else if (Block && badCFG)
3468  return nullptr;
3469  }
3470 
3471  // Because of short-circuit evaluation, the condition of the loop can span
3472  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3473  // evaluate the condition.
3474  CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
3475 
3476  do {
3477  Expr *C = W->getCond();
3478 
3479  // Specially handle logical operators, which have a slightly
3480  // more optimal CFG representation.
3481  if (BinaryOperator *Cond = dyn_cast<BinaryOperator>(C->IgnoreParens()))
3482  if (Cond->isLogicalOp()) {
3483  std::tie(EntryConditionBlock, ExitConditionBlock) =
3484  VisitLogicalOperator(Cond, W, BodyBlock, LoopSuccessor);
3485  break;
3486  }
3487 
3488  // The default case when not handling logical operators.
3489  ExitConditionBlock = createBlock(false);
3490  ExitConditionBlock->setTerminator(W);
3491 
3492  // Now add the actual condition to the condition block.
3493  // Because the condition itself may contain control-flow, new blocks may
3494  // be created. Thus we update "Succ" after adding the condition.
3495  Block = ExitConditionBlock;
3496  Block = EntryConditionBlock = addStmt(C);
3497 
3498  // If this block contains a condition variable, add both the condition
3499  // variable and initializer to the CFG.
3500  if (VarDecl *VD = W->getConditionVariable()) {
3501  if (Expr *Init = VD->getInit()) {
3502  autoCreateBlock();
3503  const DeclStmt *DS = W->getConditionVariableDeclStmt();
3504  assert(DS->isSingleDecl());
3505  findConstructionContexts(
3506  ConstructionContextLayer::create(cfg->getBumpVectorContext(),
3507  const_cast<DeclStmt *>(DS)),
3508  Init);
3509  appendStmt(Block, DS);
3510  EntryConditionBlock = addStmt(Init);
3511  assert(Block == EntryConditionBlock);
3512  maybeAddScopeBeginForVarDecl(EntryConditionBlock, VD, C);
3513  }
3514  }
3515 
3516  if (Block && badCFG)
3517  return nullptr;
3518 
3519  // See if this is a known constant.
3520  const TryResult& KnownVal = tryEvaluateBool(C);
3521 
3522  // Add the loop body entry as a successor to the condition.
3523  addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
3524  // Link up the condition block with the code that follows the loop. (the
3525  // false branch).
3526  addSuccessor(ExitConditionBlock,
3527  KnownVal.isTrue() ? nullptr : LoopSuccessor);
3528  } while(false);
3529 
3530  // Link up the loop-back block to the entry condition block.
3531  addSuccessor(TransitionBlock, EntryConditionBlock);
3532 
3533  // There can be no more statements in the condition block since we loop back
3534  // to this block. NULL out Block to force lazy creation of another block.
3535  Block = nullptr;
3536 
3537  // Return the condition block, which is the dominating block for the loop.
3538  Succ = EntryConditionBlock;
3539  return EntryConditionBlock;
3540 }
3541 
3542 CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) {
3543  // FIXME: For now we pretend that @catch and the code it contains does not
3544  // exit.
3545  return Block;
3546 }
3547 
3548 CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) {
3549  // FIXME: This isn't complete. We basically treat @throw like a return
3550  // statement.
3551 
3552  // If we were in the middle of a block we stop processing that block.
3553  if (badCFG)
3554  return nullptr;
3555 
3556  // Create the new block.
3557  Block = createBlock(false);
3558 
3559  // The Exit block is the only successor.
3560  addSuccessor(Block, &cfg->getExit());
3561 
3562  // Add the statement to the block. This may create new blocks if S contains
3563  // control-flow (short-circuit operations).
3564  return VisitStmt(S, AddStmtChoice::AlwaysAdd);
3565 }
3566 
3567 CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) {
3568  // If we were in the middle of a block we stop processing that block.
3569  if (badCFG)
3570  return nullptr;
3571 
3572  // Create the new block.
3573  Block = createBlock(false);
3574 
3575  if (TryTerminatedBlock)
3576  // The current try statement is the only successor.
3577  addSuccessor(Block, TryTerminatedBlock);
3578  else
3579  // otherwise the Exit block is the only successor.
3580  addSuccessor(Block, &cfg->getExit());
3581 
3582  // Add the statement to the block. This may create new blocks if S contains
3583  // control-flow (short-circuit operations).
3584  return VisitStmt(T, AddStmtChoice::AlwaysAdd);
3585 }
3586 
3587 CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) {
3588  CFGBlock *LoopSuccessor = nullptr;
3589 
3590  addLoopExit(D);
3591 
3592  // "do...while" is a control-flow statement. Thus we stop processing the
3593  // current block.
3594  if (Block) {
3595  if (badCFG)
3596  return nullptr;
3597  LoopSuccessor = Block;
3598  } else
3599  LoopSuccessor = Succ;
3600 
3601  // Because of short-circuit evaluation, the condition of the loop can span
3602  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3603  // evaluate the condition.
3604  CFGBlock *ExitConditionBlock = createBlock(false);
3605  CFGBlock *EntryConditionBlock = ExitConditionBlock;
3606 
3607  // Set the terminator for the "exit" condition block.
3608  ExitConditionBlock->setTerminator(D);
3609 
3610  // Now add the actual condition to the condition block. Because the condition
3611  // itself may contain control-flow, new blocks may be created.
3612  if (Stmt *C = D->getCond()) {
3613  Block = ExitConditionBlock;
3614  EntryConditionBlock = addStmt(C);
3615  if (Block) {
3616  if (badCFG)
3617  return nullptr;
3618  }
3619  }
3620 
3621  // The condition block is the implicit successor for the loop body.
3622  Succ = EntryConditionBlock;
3623 
3624  // See if this is a known constant.
3625  const TryResult &KnownVal = tryEvaluateBool(D->getCond());
3626 
3627  // Process the loop body.
3628  CFGBlock *BodyBlock = nullptr;
3629  {
3630  assert(D->getBody());
3631 
3632  // Save the current values for Block, Succ, and continue and break targets
3633  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3634  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3635  save_break(BreakJumpTarget);
3636 
3637  // All continues within this loop should go to the condition block
3638  ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos);
3639 
3640  // All breaks should go to the code following the loop.
3641  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3642 
3643  // NULL out Block to force lazy instantiation of blocks for the body.
3644  Block = nullptr;
3645 
3646  // If body is not a compound statement create implicit scope
3647  // and add destructors.
3648  if (!isa<CompoundStmt>(D->getBody()))
3649  addLocalScopeAndDtors(D->getBody());
3650 
3651  // Create the body. The returned block is the entry to the loop body.
3652  BodyBlock = addStmt(D->getBody());
3653 
3654  if (!BodyBlock)
3655  BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)"
3656  else if (Block) {
3657  if (badCFG)
3658  return nullptr;
3659  }
3660 
3661  // Add an intermediate block between the BodyBlock and the
3662  // ExitConditionBlock to represent the "loop back" transition. Create an
3663  // empty block to represent the transition block for looping back to the
3664  // head of the loop.
3665  // FIXME: Can we do this more efficiently without adding another block?
3666  Block = nullptr;
3667  Succ = BodyBlock;
3668  CFGBlock *LoopBackBlock = createBlock();
3669  LoopBackBlock->setLoopTarget(D);
3670 
3671  if (!KnownVal.isFalse())
3672  // Add the loop body entry as a successor to the condition.
3673  addSuccessor(ExitConditionBlock, LoopBackBlock);
3674  else
3675  addSuccessor(ExitConditionBlock, nullptr);
3676  }
3677 
3678  // Link up the condition block with the code that follows the loop.
3679  // (the false branch).
3680  addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
3681 
3682  // There can be no more statements in the body block(s) since we loop back to
3683  // the body. NULL out Block to force lazy creation of another block.
3684  Block = nullptr;
3685 
3686  // Return the loop body, which is the dominating block for the loop.
3687  Succ = BodyBlock;
3688  return BodyBlock;
3689 }
3690 
3691 CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) {
3692  // "continue" is a control-flow statement. Thus we stop processing the
3693  // current block.
3694  if (badCFG)
3695  return nullptr;
3696 
3697  // Now create a new block that ends with the continue statement.
3698  Block = createBlock(false);
3699  Block->setTerminator(C);
3700 
3701  // If there is no target for the continue, then we are looking at an
3702  // incomplete AST. This means the CFG cannot be constructed.
3703  if (ContinueJumpTarget.block) {
3704  addAutomaticObjHandling(ScopePos, ContinueJumpTarget.scopePosition, C);
3705  addSuccessor(Block, ContinueJumpTarget.block);
3706  } else
3707  badCFG = true;
3708 
3709  return Block;
3710 }
3711 
3712 CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
3713  AddStmtChoice asc) {
3714  if (asc.alwaysAdd(*this, E)) {
3715  autoCreateBlock();
3716  appendStmt(Block, E);
3717  }
3718 
3719  // VLA types have expressions that must be evaluated.
3720  CFGBlock *lastBlock = Block;
3721 
3722  if (E->isArgumentType()) {
3723  for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr());
3724  VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr()))
3725  lastBlock = addStmt(VA->getSizeExpr());
3726  }
3727  return lastBlock;
3728 }
3729 
3730 /// VisitStmtExpr - Utility method to handle (nested) statement
3731 /// expressions (a GCC extension).
3732 CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) {
3733  if (asc.alwaysAdd(*this, SE)) {
3734  autoCreateBlock();
3735  appendStmt(Block, SE);
3736  }
3737  return VisitCompoundStmt(SE->getSubStmt());
3738 }
3739 
3740 CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) {
3741  // "switch" is a control-flow statement. Thus we stop processing the current
3742  // block.
3743  CFGBlock *SwitchSuccessor = nullptr;
3744 
3745  // Save local scope position because in case of condition variable ScopePos
3746  // won't be restored when traversing AST.
3747  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3748 
3749  // Create local scope for C++17 switch init-stmt if one exists.
3750  if (Stmt *Init = Terminator->getInit())
3751  addLocalScopeForStmt(Init);
3752 
3753  // Create local scope for possible condition variable.
3754  // Store scope position. Add implicit destructor.
3755  if (VarDecl *VD = Terminator->getConditionVariable())
3756  addLocalScopeForVarDecl(VD);
3757 
3758  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), Terminator);
3759 
3760  if (Block) {
3761  if (badCFG)
3762  return nullptr;
3763  SwitchSuccessor = Block;
3764  } else SwitchSuccessor = Succ;
3765 
3766  // Save the current "switch" context.
3767  SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock),
3768  save_default(DefaultCaseBlock);
3769  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3770 
3771  // Set the "default" case to be the block after the switch statement. If the
3772  // switch statement contains a "default:", this value will be overwritten with
3773  // the block for that code.
3774  DefaultCaseBlock = SwitchSuccessor;
3775 
3776  // Create a new block that will contain the switch statement.
3777  SwitchTerminatedBlock = createBlock(false);
3778 
3779  // Now process the switch body. The code after the switch is the implicit
3780  // successor.
3781  Succ = SwitchSuccessor;
3782  BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos);
3783 
3784  // When visiting the body, the case statements should automatically get linked
3785  // up to the switch. We also don't keep a pointer to the body, since all
3786  // control-flow from the switch goes to case/default statements.
3787  assert(Terminator->getBody() && "switch must contain a non-NULL body");
3788  Block = nullptr;
3789 
3790  // For pruning unreachable case statements, save the current state
3791  // for tracking the condition value.
3792  SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered,
3793  false);
3794 
3795  // Determine if the switch condition can be explicitly evaluated.
3796  assert(Terminator->getCond() && "switch condition must be non-NULL");
3797  Expr::EvalResult result;
3798  bool b = tryEvaluate(Terminator->getCond(), result);
3799  SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond,
3800  b ? &result : nullptr);
3801 
3802  // If body is not a compound statement create implicit scope
3803  // and add destructors.
3804  if (!isa<CompoundStmt>(Terminator->getBody()))
3805  addLocalScopeAndDtors(Terminator->getBody());
3806 
3807  addStmt(Terminator->getBody());
3808  if (Block) {
3809  if (badCFG)
3810  return nullptr;
3811  }
3812 
3813  // If we have no "default:" case, the default transition is to the code
3814  // following the switch body. Moreover, take into account if all the
3815  // cases of a switch are covered (e.g., switching on an enum value).
3816  //
3817  // Note: We add a successor to a switch that is considered covered yet has no
3818  // case statements if the enumeration has no enumerators.
3819  bool SwitchAlwaysHasSuccessor = false;
3820  SwitchAlwaysHasSuccessor |= switchExclusivelyCovered;
3821  SwitchAlwaysHasSuccessor |= Terminator->isAllEnumCasesCovered() &&
3822  Terminator->getSwitchCaseList();
3823  addSuccessor(SwitchTerminatedBlock, DefaultCaseBlock,
3824  !SwitchAlwaysHasSuccessor);
3825 
3826  // Add the terminator and condition in the switch block.
3827  SwitchTerminatedBlock->setTerminator(Terminator);
3828  Block = SwitchTerminatedBlock;
3829  CFGBlock *LastBlock = addStmt(Terminator->getCond());
3830 
3831  // If the SwitchStmt contains a condition variable, add both the
3832  // SwitchStmt and the condition variable initialization to the CFG.
3833  if (VarDecl *VD = Terminator->getConditionVariable()) {
3834  if (Expr *Init = VD->getInit()) {
3835  autoCreateBlock();
3836  appendStmt(Block, Terminator->getConditionVariableDeclStmt());
3837  LastBlock = addStmt(Init);
3838  maybeAddScopeBeginForVarDecl(LastBlock, VD, Init);
3839  }
3840  }
3841 
3842  // Finally, if the SwitchStmt contains a C++17 init-stmt, add it to the CFG.
3843  if (Stmt *Init = Terminator->getInit()) {
3844  autoCreateBlock();
3845  LastBlock = addStmt(Init);
3846  }
3847 
3848  return LastBlock;
3849 }
3850 
3851 static bool shouldAddCase(bool &switchExclusivelyCovered,
3852  const Expr::EvalResult *switchCond,
3853  const CaseStmt *CS,
3854  ASTContext &Ctx) {
3855  if (!switchCond)
3856  return true;
3857 
3858  bool addCase = false;
3859 
3860  if (!switchExclusivelyCovered) {
3861  if (switchCond->Val.isInt()) {
3862  // Evaluate the LHS of the case value.
3863  const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx);
3864  const llvm::APSInt &condInt = switchCond->Val.getInt();
3865 
3866  if (condInt == lhsInt) {
3867  addCase = true;
3868  switchExclusivelyCovered = true;
3869  }
3870  else if (condInt > lhsInt) {
3871  if (const Expr *RHS = CS->getRHS()) {
3872  // Evaluate the RHS of the case value.
3873  const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx);
3874  if (V2 >= condInt) {
3875  addCase = true;
3876  switchExclusivelyCovered = true;
3877  }
3878  }
3879  }
3880  }
3881  else
3882  addCase = true;
3883  }
3884  return addCase;
3885 }
3886 
3887 CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) {
3888  // CaseStmts are essentially labels, so they are the first statement in a
3889  // block.
3890  CFGBlock *TopBlock = nullptr, *LastBlock = nullptr;
3891 
3892  if (Stmt *Sub = CS->getSubStmt()) {
3893  // For deeply nested chains of CaseStmts, instead of doing a recursion
3894  // (which can blow out the stack), manually unroll and create blocks
3895  // along the way.
3896  while (isa<CaseStmt>(Sub)) {
3897  CFGBlock *currentBlock = createBlock(false);
3898  currentBlock->setLabel(CS);
3899 
3900  if (TopBlock)
3901  addSuccessor(LastBlock, currentBlock);
3902  else
3903  TopBlock = currentBlock;
3904 
3905  addSuccessor(SwitchTerminatedBlock,
3906  shouldAddCase(switchExclusivelyCovered, switchCond,
3907  CS, *Context)
3908  ? currentBlock : nullptr);
3909 
3910  LastBlock = currentBlock;
3911  CS = cast<CaseStmt>(Sub);
3912  Sub = CS->getSubStmt();
3913  }
3914 
3915  addStmt(Sub);
3916  }
3917 
3918  CFGBlock *CaseBlock = Block;
3919  if (!CaseBlock)
3920  CaseBlock = createBlock();
3921 
3922  // Cases statements partition blocks, so this is the top of the basic block we
3923  // were processing (the "case XXX:" is the label).
3924  CaseBlock->setLabel(CS);
3925 
3926  if (badCFG)
3927  return nullptr;
3928 
3929  // Add this block to the list of successors for the block with the switch
3930  // statement.
3931  assert(SwitchTerminatedBlock);
3932  addSuccessor(SwitchTerminatedBlock, CaseBlock,
3933  shouldAddCase(switchExclusivelyCovered, switchCond,
3934  CS, *Context));
3935 
3936  // We set Block to NULL to allow lazy creation of a new block (if necessary)
3937  Block = nullptr;
3938 
3939  if (TopBlock) {
3940  addSuccessor(LastBlock, CaseBlock);
3941  Succ = TopBlock;
3942  } else {
3943  // This block is now the implicit successor of other blocks.
3944  Succ = CaseBlock;
3945  }
3946 
3947  return Succ;
3948 }
3949 
3950 CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) {
3951  if (Terminator->getSubStmt())
3952  addStmt(Terminator->getSubStmt());
3953 
3954  DefaultCaseBlock = Block;
3955 
3956  if (!DefaultCaseBlock)
3957  DefaultCaseBlock = createBlock();
3958 
3959  // Default statements partition blocks, so this is the top of the basic block
3960  // we were processing (the "default:" is the label).
3961  DefaultCaseBlock->setLabel(Terminator);
3962 
3963  if (badCFG)
3964  return nullptr;
3965 
3966  // Unlike case statements, we don't add the default block to the successors
3967  // for the switch statement immediately. This is done when we finish
3968  // processing the switch statement. This allows for the default case
3969  // (including a fall-through to the code after the switch statement) to always
3970  // be the last successor of a switch-terminated block.
3971 
3972  // We set Block to NULL to allow lazy creation of a new block (if necessary)
3973  Block = nullptr;
3974 
3975  // This block is now the implicit successor of other blocks.
3976  Succ = DefaultCaseBlock;
3977 
3978  return DefaultCaseBlock;
3979 }
3980 
3981 CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) {
3982  // "try"/"catch" is a control-flow statement. Thus we stop processing the
3983  // current block.
3984  CFGBlock *TrySuccessor = nullptr;
3985 
3986  if (Block) {
3987  if (badCFG)
3988  return nullptr;
3989  TrySuccessor = Block;
3990  } else TrySuccessor = Succ;
3991 
3992  CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock;
3993 
3994  // Create a new block that will contain the try statement.
3995  CFGBlock *NewTryTerminatedBlock = createBlock(false);
3996  // Add the terminator in the try block.
3997  NewTryTerminatedBlock->setTerminator(Terminator);
3998 
3999  bool HasCatchAll = false;
4000  for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) {
4001  // The code after the try is the implicit successor.
4002  Succ = TrySuccessor;
4003  CXXCatchStmt *CS = Terminator->getHandler(h);
4004  if (CS->getExceptionDecl() == nullptr) {
4005  HasCatchAll = true;
4006  }
4007  Block = nullptr;
4008  CFGBlock *CatchBlock = VisitCXXCatchStmt(CS);
4009  if (!CatchBlock)
4010  return nullptr;
4011  // Add this block to the list of successors for the block with the try
4012  // statement.
4013  addSuccessor(NewTryTerminatedBlock, CatchBlock);
4014  }
4015  if (!HasCatchAll) {
4016  if (PrevTryTerminatedBlock)
4017  addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock);
4018  else
4019  addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
4020  }
4021 
4022  // The code after the try is the implicit successor.
4023  Succ = TrySuccessor;
4024 
4025  // Save the current "try" context.
4026  SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock);
4027  cfg->addTryDispatchBlock(TryTerminatedBlock);
4028 
4029  assert(Terminator->getTryBlock() && "try must contain a non-NULL body");
4030  Block = nullptr;
4031  return addStmt(Terminator->getTryBlock());
4032 }
4033 
4034 CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) {
4035  // CXXCatchStmt are treated like labels, so they are the first statement in a
4036  // block.
4037 
4038  // Save local scope position because in case of exception variable ScopePos
4039  // won't be restored when traversing AST.
4040  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
4041 
4042  // Create local scope for possible exception variable.
4043  // Store scope position. Add implicit destructor.
4044  if (VarDecl *VD = CS->getExceptionDecl()) {
4045  LocalScope::const_iterator BeginScopePos = ScopePos;
4046  addLocalScopeForVarDecl(VD);
4047  addAutomaticObjHandling(ScopePos, BeginScopePos, CS);
4048  }
4049 
4050  if (CS->getHandlerBlock())
4051  addStmt(CS->getHandlerBlock());
4052 
4053  CFGBlock *CatchBlock = Block;
4054  if (!CatchBlock)
4055  CatchBlock = createBlock();
4056 
4057  // CXXCatchStmt is more than just a label. They have semantic meaning
4058  // as well, as they implicitly "initialize" the catch variable. Add
4059  // it to the CFG as a CFGElement so that the control-flow of these
4060  // semantics gets captured.
4061  appendStmt(CatchBlock, CS);
4062 
4063  // Also add the CXXCatchStmt as a label, to mirror handling of regular
4064  // labels.
4065  CatchBlock->setLabel(CS);
4066 
4067  // Bail out if the CFG is bad.
4068  if (badCFG)
4069  return nullptr;
4070 
4071  // We set Block to NULL to allow lazy creation of a new block (if necessary)
4072  Block = nullptr;
4073 
4074  return CatchBlock;
4075 }
4076 
4077 CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) {
4078  // C++0x for-range statements are specified as [stmt.ranged]:
4079  //
4080  // {
4081  // auto && __range = range-init;
4082  // for ( auto __begin = begin-expr,
4083  // __end = end-expr;
4084  // __begin != __end;
4085  // ++__begin ) {
4086  // for-range-declaration = *__begin;
4087  // statement
4088  // }
4089  // }
4090 
4091  // Save local scope position before the addition of the implicit variables.
4092  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
4093 
4094  // Create local scopes and destructors for range, begin and end variables.
4095  if (Stmt *Range = S->getRangeStmt())
4096  addLocalScopeForStmt(Range);
4097  if (Stmt *Begin = S->getBeginStmt())
4098  addLocalScopeForStmt(Begin);
4099  if (Stmt *End = S->getEndStmt())
4100  addLocalScopeForStmt(End);
4101  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), S);
4102 
4103  LocalScope::const_iterator ContinueScopePos = ScopePos;
4104 
4105  // "for" is a control-flow statement. Thus we stop processing the current
4106  // block.
4107  CFGBlock *LoopSuccessor = nullptr;
4108  if (Block) {
4109  if (badCFG)
4110  return nullptr;
4111  LoopSuccessor = Block;
4112  } else
4113  LoopSuccessor = Succ;
4114 
4115  // Save the current value for the break targets.
4116  // All breaks should go to the code following the loop.
4117  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
4118  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
4119 
4120  // The block for the __begin != __end expression.
4121  CFGBlock *ConditionBlock = createBlock(false);
4122  ConditionBlock->setTerminator(S);
4123 
4124  // Now add the actual condition to the condition block.
4125  if (Expr *C = S->getCond()) {
4126  Block = ConditionBlock;
4127  CFGBlock *BeginConditionBlock = addStmt(C);
4128  if (badCFG)
4129  return nullptr;
4130  assert(BeginConditionBlock == ConditionBlock &&
4131  "condition block in for-range was unexpectedly complex");
4132  (void)BeginConditionBlock;
4133  }
4134 
4135  // The condition block is the implicit successor for the loop body as well as
4136  // any code above the loop.
4137  Succ = ConditionBlock;
4138 
4139  // See if this is a known constant.
4140  TryResult KnownVal(true);
4141 
4142  if (S->getCond())
4143  KnownVal = tryEvaluateBool(S->getCond());
4144 
4145  // Now create the loop body.
4146  {
4147  assert(S->getBody());
4148 
4149  // Save the current values for Block, Succ, and continue targets.
4150  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
4151  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
4152 
4153  // Generate increment code in its own basic block. This is the target of
4154  // continue statements.
4155  Block = nullptr;
4156  Succ = addStmt(S->getInc());
4157  if (badCFG)
4158  return nullptr;
4159  ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
4160 
4161  // The starting block for the loop increment is the block that should
4162  // represent the 'loop target' for looping back to the start of the loop.
4163  ContinueJumpTarget.block->setLoopTarget(S);
4164 
4165  // Finish up the increment block and prepare to start the loop body.
4166  assert(Block);
4167  if (badCFG)
4168  return nullptr;
4169  Block = nullptr;
4170 
4171  // Add implicit scope and dtors for loop variable.
4172  addLocalScopeAndDtors(S->getLoopVarStmt());
4173 
4174  // Populate a new block to contain the loop body and loop variable.
4175  addStmt(S->getBody());
4176  if (badCFG)
4177  return nullptr;
4178  CFGBlock *LoopVarStmtBlock = addStmt(S->getLoopVarStmt());
4179  if (badCFG)
4180  return nullptr;
4181 
4182  // This new body block is a successor to our condition block.
4183  addSuccessor(ConditionBlock,
4184  KnownVal.isFalse() ? nullptr : LoopVarStmtBlock);
4185  }
4186 
4187  // Link up the condition block with the code that follows the loop (the
4188  // false branch).
4189  addSuccessor(ConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
4190 
4191  // Add the initialization statements.
4192  Block = createBlock();
4193  addStmt(S->getBeginStmt());
4194  addStmt(S->getEndStmt());
4195  return addStmt(S->getRangeStmt());
4196 }
4197 
4198 CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E,
4199  AddStmtChoice asc) {
4200  if (BuildOpts.AddTemporaryDtors) {
4201  // If adding implicit destructors visit the full expression for adding
4202  // destructors of temporaries.
4203  TempDtorContext Context;
4204  VisitForTemporaryDtors(E->getSubExpr(), false, Context);
4205 
4206  // Full expression has to be added as CFGStmt so it will be sequenced
4207  // before destructors of it's temporaries.
4208  asc = asc.withAlwaysAdd(true);
4209  }
4210  return Visit(E->getSubExpr(), asc);
4211 }
4212 
4213 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
4214  AddStmtChoice asc) {
4215  if (asc.alwaysAdd(*this, E)) {
4216  autoCreateBlock();
4217  appendStmt(Block, E);
4218 
4219  findConstructionContexts(
4220  ConstructionContextLayer::create(cfg->getBumpVectorContext(), E),
4221  E->getSubExpr());
4222 
4223  // We do not want to propagate the AlwaysAdd property.
4224  asc = asc.withAlwaysAdd(false);
4225  }
4226  return Visit(E->getSubExpr(), asc);
4227 }
4228 
4229 CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C,
4230  AddStmtChoice asc) {
4231  autoCreateBlock();
4232  appendConstructor(Block, C);
4233 
4234  return VisitChildren(C);
4235 }
4236 
4237 CFGBlock *CFGBuilder::VisitCXXNewExpr(CXXNewExpr *NE,
4238  AddStmtChoice asc) {
4239  autoCreateBlock();
4240  appendStmt(Block, NE);
4241 
4242  findConstructionContexts(
4243  ConstructionContextLayer::create(cfg->getBumpVectorContext(), NE),
4244  const_cast<CXXConstructExpr *>(NE->getConstructExpr()));
4245 
4246  if (NE->getInitializer())
4247  Block = Visit(NE->getInitializer());
4248 
4249  if (BuildOpts.AddCXXNewAllocator)
4250  appendNewAllocator(Block, NE);
4251 
4252  if (NE->isArray())
4253  Block = Visit(NE->getArraySize());
4254 
4256  E = NE->placement_arg_end(); I != E; ++I)
4257  Block = Visit(*I);
4258 
4259  return Block;
4260 }
4261 
4262 CFGBlock *CFGBuilder::VisitCXXDeleteExpr(CXXDeleteExpr *DE,
4263  AddStmtChoice asc) {
4264  autoCreateBlock();
4265  appendStmt(Block, DE);
4266  QualType DTy = DE->getDestroyedType();
4267  if (!DTy.isNull()) {
4268  DTy = DTy.getNonReferenceType();
4269  CXXRecordDecl *RD = Context->getBaseElementType(DTy)->getAsCXXRecordDecl();
4270  if (RD) {
4271  if (RD->isCompleteDefinition() && !RD->hasTrivialDestructor())
4272  appendDeleteDtor(Block, RD, DE);
4273  }
4274  }
4275 
4276  return VisitChildren(DE);
4277 }
4278 
4279 CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
4280  AddStmtChoice asc) {
4281  if (asc.alwaysAdd(*this, E)) {
4282  autoCreateBlock();
4283  appendStmt(Block, E);
4284  // We do not want to propagate the AlwaysAdd property.
4285  asc = asc.withAlwaysAdd(false);
4286  }
4287  return Visit(E->getSubExpr(), asc);
4288 }
4289 
4290 CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
4291  AddStmtChoice asc) {
4292  autoCreateBlock();
4293  appendConstructor(Block, C);
4294  return VisitChildren(C);
4295 }
4296 
4297 CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E,
4298  AddStmtChoice asc) {
4299  if (asc.alwaysAdd(*this, E)) {
4300  autoCreateBlock();
4301  appendStmt(Block, E);
4302  }
4303  return Visit(E->getSubExpr(), AddStmtChoice());
4304 }
4305 
4306 CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) {
4307  // Lazily create the indirect-goto dispatch block if there isn't one already.
4308  CFGBlock *IBlock = cfg->getIndirectGotoBlock();
4309 
4310  if (!IBlock) {
4311  IBlock = createBlock(false);
4312  cfg->setIndirectGotoBlock(IBlock);
4313  }
4314 
4315  // IndirectGoto is a control-flow statement. Thus we stop processing the
4316  // current block and create a new one.
4317  if (badCFG)
4318  return nullptr;
4319 
4320  Block = createBlock(false);
4321  Block->setTerminator(I);
4322  addSuccessor(Block, IBlock);
4323  return addStmt(I->getTarget());
4324 }
4325 
4326 CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary,
4327  TempDtorContext &Context) {
4328  assert(BuildOpts.AddImplicitDtors && BuildOpts.AddTemporaryDtors);
4329 
4330 tryAgain:
4331  if (!E) {
4332  badCFG = true;
4333  return nullptr;
4334  }
4335  switch (E->getStmtClass()) {
4336  default:
4337  return VisitChildrenForTemporaryDtors(E, Context);
4338 
4339  case Stmt::BinaryOperatorClass:
4340  return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E),
4341  Context);
4342 
4343  case Stmt::CXXBindTemporaryExprClass:
4344  return VisitCXXBindTemporaryExprForTemporaryDtors(
4345  cast<CXXBindTemporaryExpr>(E), BindToTemporary, Context);
4346 
4347  case Stmt::BinaryConditionalOperatorClass:
4348  case Stmt::ConditionalOperatorClass:
4349  return VisitConditionalOperatorForTemporaryDtors(
4350  cast<AbstractConditionalOperator>(E), BindToTemporary, Context);
4351 
4352  case Stmt::ImplicitCastExprClass:
4353  // For implicit cast we want BindToTemporary to be passed further.
4354  E = cast<CastExpr>(E)->getSubExpr();
4355  goto tryAgain;
4356 
4357  case Stmt::CXXFunctionalCastExprClass:
4358  // For functional cast we want BindToTemporary to be passed further.
4359  E = cast<CXXFunctionalCastExpr>(E)->getSubExpr();
4360  goto tryAgain;
4361 
4362  case Stmt::ParenExprClass:
4363  E = cast<ParenExpr>(E)->getSubExpr();
4364  goto tryAgain;
4365 
4366  case Stmt::MaterializeTemporaryExprClass: {
4367  const MaterializeTemporaryExpr* MTE = cast<MaterializeTemporaryExpr>(E);
4368  BindToTemporary = (MTE->getStorageDuration() != SD_FullExpression);
4369  SmallVector<const Expr *, 2> CommaLHSs;
4371  // Find the expression whose lifetime needs to be extended.
4372  E = const_cast<Expr *>(
4373  cast<MaterializeTemporaryExpr>(E)
4374  ->GetTemporaryExpr()
4375  ->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments));
4376  // Visit the skipped comma operator left-hand sides for other temporaries.
4377  for (const Expr *CommaLHS : CommaLHSs) {
4378  VisitForTemporaryDtors(const_cast<Expr *>(CommaLHS),
4379  /*BindToTemporary=*/false, Context);
4380  }
4381  goto tryAgain;
4382  }
4383 
4384  case Stmt::BlockExprClass:
4385  // Don't recurse into blocks; their subexpressions don't get evaluated
4386  // here.
4387  return Block;
4388 
4389  case Stmt::LambdaExprClass: {
4390  // For lambda expressions, only recurse into the capture initializers,
4391  // and not the body.
4392  auto *LE = cast<LambdaExpr>(E);
4393  CFGBlock *B = Block;
4394  for (Expr *Init : LE->capture_inits()) {
4395  if (CFGBlock *R = VisitForTemporaryDtors(
4396  Init, /*BindToTemporary=*/false, Context))
4397  B = R;
4398  }
4399  return B;
4400  }
4401 
4402  case Stmt::CXXDefaultArgExprClass:
4403  E = cast<CXXDefaultArgExpr>(E)->getExpr();
4404  goto tryAgain;
4405 
4406  case Stmt::CXXDefaultInitExprClass:
4407  E = cast<CXXDefaultInitExpr>(E)->getExpr();
4408  goto tryAgain;
4409  }
4410 }
4411 
4412 CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E,
4413  TempDtorContext &Context) {
4414  if (isa<LambdaExpr>(E)) {
4415  // Do not visit the children of lambdas; they have their own CFGs.
4416  return Block;
4417  }
4418 
4419  // When visiting children for destructors we want to visit them in reverse
4420  // order that they will appear in the CFG. Because the CFG is built
4421  // bottom-up, this means we visit them in their natural order, which
4422  // reverses them in the CFG.
4423  CFGBlock *B = Block;
4424  for (Stmt *Child : E->children())
4425  if (Child)
4426  if (CFGBlock *R = VisitForTemporaryDtors(Child, false, Context))
4427  B = R;
4428 
4429  return B;
4430 }
4431 
4432 CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(
4433  BinaryOperator *E, TempDtorContext &Context) {
4434  if (E->isLogicalOp()) {
4435  VisitForTemporaryDtors(E->getLHS(), false, Context);
4436  TryResult RHSExecuted = tryEvaluateBool(E->getLHS());
4437  if (RHSExecuted.isKnown() && E->getOpcode() == BO_LOr)
4438  RHSExecuted.negate();
4439 
4440  // We do not know at CFG-construction time whether the right-hand-side was
4441  // executed, thus we add a branch node that depends on the temporary
4442  // constructor call.
4443  TempDtorContext RHSContext(
4444  bothKnownTrue(Context.KnownExecuted, RHSExecuted));
4445  VisitForTemporaryDtors(E->getRHS(), false, RHSContext);
4446  InsertTempDtorDecisionBlock(RHSContext);
4447 
4448  return Block;
4449  }
4450 
4451  if (E->isAssignmentOp()) {
4452  // For assignment operator (=) LHS expression is visited
4453  // before RHS expression. For destructors visit them in reverse order.
4454  CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
4455  CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
4456  return LHSBlock ? LHSBlock : RHSBlock;
4457  }
4458 
4459  // For any other binary operator RHS expression is visited before
4460  // LHS expression (order of children). For destructors visit them in reverse
4461  // order.
4462  CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
4463  CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
4464  return RHSBlock ? RHSBlock : LHSBlock;
4465 }
4466 
4467 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors(
4468  CXXBindTemporaryExpr *E, bool BindToTemporary, TempDtorContext &Context) {
4469  // First add destructors for temporaries in subexpression.
4470  CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr(), false, Context);
4471  if (!BindToTemporary) {
4472  // If lifetime of temporary is not prolonged (by assigning to constant
4473  // reference) add destructor for it.
4474 
4475  const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor();
4476 
4477  if (Dtor->getParent()->isAnyDestructorNoReturn()) {
4478  // If the destructor is marked as a no-return destructor, we need to
4479  // create a new block for the destructor which does not have as a
4480  // successor anything built thus far. Control won't flow out of this
4481  // block.
4482  if (B) Succ = B;
4483  Block = createNoReturnBlock();
4484  } else if (Context.needsTempDtorBranch()) {
4485  // If we need to introduce a branch, we add a new block that we will hook
4486  // up to a decision block later.
4487  if (B) Succ = B;
4488  Block = createBlock();
4489  } else {
4490  autoCreateBlock();
4491  }
4492  if (Context.needsTempDtorBranch()) {
4493  Context.setDecisionPoint(Succ, E);
4494  }
4495  appendTemporaryDtor(Block, E);
4496 
4497  B = Block;
4498  }
4499  return B;
4500 }
4501 
4502 void CFGBuilder::InsertTempDtorDecisionBlock(const TempDtorContext &Context,
4503  CFGBlock *FalseSucc) {
4504  if (!Context.TerminatorExpr) {
4505  // If no temporary was found, we do not need to insert a decision point.
4506  return;
4507  }
4508  assert(Context.TerminatorExpr);
4509  CFGBlock *Decision = createBlock(false);
4510  Decision->setTerminator(CFGTerminator(Context.TerminatorExpr, true));
4511  addSuccessor(Decision, Block, !Context.KnownExecuted.isFalse());
4512  addSuccessor(Decision, FalseSucc ? FalseSucc : Context.Succ,
4513  !Context.KnownExecuted.isTrue());
4514  Block = Decision;
4515 }
4516 
4517 CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors(
4518  AbstractConditionalOperator *E, bool BindToTemporary,
4519  TempDtorContext &Context) {
4520  VisitForTemporaryDtors(E->getCond(), false, Context);
4521  CFGBlock *ConditionBlock = Block;
4522  CFGBlock *ConditionSucc = Succ;
4523  TryResult ConditionVal = tryEvaluateBool(E->getCond());
4524  TryResult NegatedVal = ConditionVal;
4525  if (NegatedVal.isKnown()) NegatedVal.negate();
4526 
4527  TempDtorContext TrueContext(
4528  bothKnownTrue(Context.KnownExecuted, ConditionVal));
4529  VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary, TrueContext);
4530  CFGBlock *TrueBlock = Block;
4531 
4532  Block = ConditionBlock;
4533  Succ = ConditionSucc;
4534  TempDtorContext FalseContext(
4535  bothKnownTrue(Context.KnownExecuted, NegatedVal));
4536  VisitForTemporaryDtors(E->getFalseExpr(), BindToTemporary, FalseContext);
4537 
4538  if (TrueContext.TerminatorExpr && FalseContext.TerminatorExpr) {
4539  InsertTempDtorDecisionBlock(FalseContext, TrueBlock);
4540  } else if (TrueContext.TerminatorExpr) {
4541  Block = TrueBlock;
4542  InsertTempDtorDecisionBlock(TrueContext);
4543  } else {
4544  InsertTempDtorDecisionBlock(FalseContext);
4545  }
4546  return Block;
4547 }
4548 
4549 /// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has
4550 /// no successors or predecessors. If this is the first block created in the
4551 /// CFG, it is automatically set to be the Entry and Exit of the CFG.
4553  bool first_block = begin() == end();
4554 
4555  // Create the block.
4556  CFGBlock *Mem = getAllocator().Allocate<CFGBlock>();
4557  new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this);
4558  Blocks.push_back(Mem, BlkBVC);
4559 
4560  // If this is the first block, set it as the Entry and Exit.
4561  if (first_block)
4562  Entry = Exit = &back();
4563 
4564  // Return the block.
4565  return &back();
4566 }
4567 
4568 /// buildCFG - Constructs a CFG from an AST.
4569 std::unique_ptr<CFG> CFG::buildCFG(const Decl *D, Stmt *Statement,
4570  ASTContext *C, const BuildOptions &BO) {
4571  CFGBuilder Builder(C, BO);
4572  return Builder.buildCFG(D, Statement);
4573 }
4574 
4575 const CXXDestructorDecl *
4577  switch (getKind()) {
4580  case CFGElement::LoopExit:
4582  case CFGElement::Statement:
4586  case CFGElement::ScopeEnd:
4587  llvm_unreachable("getDestructorDecl should only be used with "
4588  "ImplicitDtors");
4590  const VarDecl *var = castAs<CFGAutomaticObjDtor>().getVarDecl();
4591  QualType ty = var->getType();
4592 
4593  // FIXME: See CFGBuilder::addLocalScopeForVarDecl.
4594  //
4595  // Lifetime-extending constructs are handled here. This works for a single
4596  // temporary in an initializer expression.
4597  if (ty->isReferenceType()) {
4598  if (const Expr *Init = var->getInit()) {
4599  ty = getReferenceInitTemporaryType(astContext, Init);
4600  }
4601  }
4602 
4603  while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) {
4604  ty = arrayType->getElementType();
4605  }
4606  const RecordType *recordType = ty->getAs<RecordType>();
4607  const CXXRecordDecl *classDecl =
4608  cast<CXXRecordDecl>(recordType->getDecl());
4609  return classDecl->getDestructor();
4610  }
4611  case CFGElement::DeleteDtor: {
4612  const CXXDeleteExpr *DE = castAs<CFGDeleteDtor>().getDeleteExpr();
4613  QualType DTy = DE->getDestroyedType();
4614  DTy = DTy.getNonReferenceType();
4615  const CXXRecordDecl *classDecl =
4616  astContext.getBaseElementType(DTy)->getAsCXXRecordDecl();
4617  return classDecl->getDestructor();
4618  }
4620  const CXXBindTemporaryExpr *bindExpr =
4621  castAs<CFGTemporaryDtor>().getBindTemporaryExpr();
4622  const CXXTemporary *temp = bindExpr->getTemporary();
4623  return temp->getDestructor();
4624  }
4625  case CFGElement::BaseDtor:
4627  // Not yet supported.
4628  return nullptr;
4629  }
4630  llvm_unreachable("getKind() returned bogus value");
4631 }
4632 
4633 bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const {
4634  if (const CXXDestructorDecl *DD = getDestructorDecl(astContext))
4635  return DD->isNoReturn();
4636  return false;
4637 }
4638 
4639 //===----------------------------------------------------------------------===//
4640 // CFGBlock operations.
4641 //===----------------------------------------------------------------------===//
4642 
4644  : ReachableBlock(IsReachable ? B : nullptr),
4645  UnreachableBlock(!IsReachable ? B : nullptr,
4646  B && IsReachable ? AB_Normal : AB_Unreachable) {}
4647 
4649  : ReachableBlock(B),
4650  UnreachableBlock(B == AlternateBlock ? nullptr : AlternateBlock,
4651  B == AlternateBlock ? AB_Alternate : AB_Normal) {}
4652 
4654  BumpVectorContext &C) {
4655  if (CFGBlock *B = Succ.getReachableBlock())
4656  B->Preds.push_back(AdjacentBlock(this, Succ.isReachable()), C);
4657 
4658  if (CFGBlock *UnreachableB = Succ.getPossiblyUnreachableBlock())
4659  UnreachableB->Preds.push_back(AdjacentBlock(this, false), C);
4660 
4661  Succs.push_back(Succ, C);
4662 }
4663 
4665  const CFGBlock *From, const CFGBlock *To) {
4666  if (F.IgnoreNullPredecessors && !From)
4667  return true;
4668 
4669  if (To && From && F.IgnoreDefaultsWithCoveredEnums) {
4670  // If the 'To' has no label or is labeled but the label isn't a
4671  // CaseStmt then filter this edge.
4672  if (const SwitchStmt *S =
4673  dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) {
4674  if (S->isAllEnumCasesCovered()) {
4675  const Stmt *L = To->getLabel();
4676  if (!L || !isa<CaseStmt>(L))
4677  return true;
4678  }
4679  }
4680  }
4681 
4682  return false;
4683 }
4684 
4685 //===----------------------------------------------------------------------===//
4686 // CFG pretty printing
4687 //===----------------------------------------------------------------------===//
4688 
4689 namespace {
4690 
4691 class StmtPrinterHelper : public PrinterHelper {
4692  using StmtMapTy = llvm::DenseMap<const Stmt *, std::pair<unsigned, unsigned>>;
4693  using DeclMapTy = llvm::DenseMap<const Decl *, std::pair<unsigned, unsigned>>;
4694 
4695  StmtMapTy StmtMap;
4696  DeclMapTy DeclMap;
4697  signed currentBlock = 0;
4698  unsigned currStmt = 0;
4699  const LangOptions &LangOpts;
4700 
4701 public:
4702  StmtPrinterHelper(const CFG* cfg, const LangOptions &LO)
4703  : LangOpts(LO) {
4704  for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) {
4705  unsigned j = 1;
4706  for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ;
4707  BI != BEnd; ++BI, ++j ) {
4708  if (Optional<CFGStmt> SE = BI->getAs<CFGStmt>()) {
4709  const Stmt *stmt= SE->getStmt();
4710  std::pair<unsigned, unsigned> P((*I)->getBlockID(), j);
4711  StmtMap[stmt] = P;
4712 
4713  switch (stmt->getStmtClass()) {
4714  case Stmt::DeclStmtClass:
4715  DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P;
4716  break;
4717  case Stmt::IfStmtClass: {
4718  const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable();
4719  if (var)
4720  DeclMap[var] = P;
4721  break;
4722  }
4723  case Stmt::ForStmtClass: {
4724  const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable();
4725  if (var)
4726  DeclMap[var] = P;
4727  break;
4728  }
4729  case Stmt::WhileStmtClass: {
4730  const VarDecl *var =
4731  cast<WhileStmt>(stmt)->getConditionVariable();
4732  if (var)
4733  DeclMap[var] = P;
4734  break;
4735  }
4736  case Stmt::SwitchStmtClass: {
4737  const VarDecl *var =
4738  cast<SwitchStmt>(stmt)->getConditionVariable();
4739  if (var)
4740  DeclMap[var] = P;
4741  break;
4742  }
4743  case Stmt::CXXCatchStmtClass: {
4744  const VarDecl *var =
4745  cast<CXXCatchStmt>(stmt)->getExceptionDecl();
4746  if (var)
4747  DeclMap[var] = P;
4748  break;
4749  }
4750  default:
4751  break;
4752  }
4753  }
4754  }
4755  }
4756  }
4757 
4758  ~StmtPrinterHelper() override = default;
4759 
4760  const LangOptions &getLangOpts() const { return LangOpts; }
4761  void setBlockID(signed i) { currentBlock = i; }
4762  void setStmtID(unsigned i) { currStmt = i; }
4763 
4764  bool handledStmt(Stmt *S, raw_ostream &OS) override {
4765  StmtMapTy::iterator I = StmtMap.find(S);
4766 
4767  if (I == StmtMap.end())
4768  return false;
4769 
4770  if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
4771  && I->second.second == currStmt) {
4772  return false;
4773  }
4774 
4775  OS << "[B" << I->second.first << "." << I->second.second << "]";
4776  return true;
4777  }
4778 
4779  bool handleDecl(const Decl *D, raw_ostream &OS) {
4780  DeclMapTy::iterator I = DeclMap.find(D);
4781 
4782  if (I == DeclMap.end())
4783  return false;
4784 
4785  if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
4786  && I->second.second == currStmt) {
4787  return false;
4788  }
4789 
4790  OS << "[B" << I->second.first << "." << I->second.second << "]";
4791  return true;
4792  }
4793 };
4794 
4795 class CFGBlockTerminatorPrint
4796  : public StmtVisitor<CFGBlockTerminatorPrint,void> {
4797  raw_ostream &OS;
4798  StmtPrinterHelper* Helper;
4799  PrintingPolicy Policy;
4800 
4801 public:
4802  CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper,
4803  const PrintingPolicy &Policy)
4804  : OS(os), Helper(helper), Policy(Policy) {
4805  this->Policy.IncludeNewlines = false;
4806  }
4807 
4808  void VisitIfStmt(IfStmt *I) {
4809  OS << "if ";
4810  if (Stmt *C = I->getCond())
4811  C->printPretty(OS, Helper, Policy);
4812  }
4813 
4814  // Default case.
4815  void VisitStmt(Stmt *Terminator) {
4816  Terminator->printPretty(OS, Helper, Policy);
4817  }
4818 
4819  void VisitDeclStmt(DeclStmt *DS) {
4820  VarDecl *VD = cast<VarDecl>(DS->getSingleDecl());
4821  OS << "static init " << VD->getName();
4822  }
4823 
4824  void VisitForStmt(ForStmt *F) {
4825  OS << "for (" ;
4826  if (F->getInit())
4827  OS << "...";
4828  OS << "; ";
4829  if (Stmt *C = F->getCond())
4830  C->printPretty(OS, Helper, Policy);
4831  OS << "; ";
4832  if (F->getInc())
4833  OS << "...";
4834  OS << ")";
4835  }
4836 
4837  void VisitWhileStmt(WhileStmt *W) {
4838  OS << "while " ;
4839  if (Stmt *C = W->getCond())
4840  C->printPretty(OS, Helper, Policy);
4841  }
4842 
4843  void VisitDoStmt(DoStmt *D) {
4844  OS << "do ... while ";
4845  if (Stmt *C = D->getCond())
4846  C->printPretty(OS, Helper, Policy);
4847  }
4848 
4849  void VisitSwitchStmt(SwitchStmt *Terminator) {
4850  OS << "switch ";
4851  Terminator->getCond()->printPretty(OS, Helper, Policy);
4852  }
4853 
4854  void VisitCXXTryStmt(CXXTryStmt *CS) {
4855  OS << "try ...";
4856  }
4857 
4858  void VisitSEHTryStmt(SEHTryStmt *CS) {
4859  OS << "__try ...";
4860  }
4861 
4862  void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) {
4863  if (Stmt *Cond = C->getCond())
4864  Cond->printPretty(OS, Helper, Policy);
4865  OS << " ? ... : ...";
4866  }
4867 
4868  void VisitChooseExpr(ChooseExpr *C) {
4869  OS << "__builtin_choose_expr( ";
4870  if (Stmt *Cond = C->getCond())
4871  Cond->printPretty(OS, Helper, Policy);
4872  OS << " )";
4873  }
4874 
4875  void VisitIndirectGotoStmt(IndirectGotoStmt *I) {
4876  OS << "goto *";
4877  if (Stmt *T = I->getTarget())
4878  T->printPretty(OS, Helper, Policy);
4879  }
4880 
4881  void VisitBinaryOperator(BinaryOperator* B) {
4882  if (!B->isLogicalOp()) {
4883  VisitExpr(B);
4884  return;
4885  }
4886 
4887  if (B->getLHS())
4888  B->getLHS()->printPretty(OS, Helper, Policy);
4889 
4890  switch (B->getOpcode()) {
4891  case BO_LOr:
4892  OS << " || ...";
4893  return;
4894  case BO_LAnd:
4895  OS << " && ...";
4896  return;
4897  default:
4898  llvm_unreachable("Invalid logical operator.");
4899  }
4900  }
4901 
4902  void VisitExpr(Expr *E) {
4903  E->printPretty(OS, Helper, Policy);
4904  }
4905 
4906 public:
4907  void print(CFGTerminator T) {
4908  if (T.isTemporaryDtorsBranch())
4909  OS << "(Temp Dtor) ";
4910  Visit(T.getStmt());
4911  }
4912 };
4913 
4914 } // namespace
4915 
4916 static void print_initializer(raw_ostream &OS, StmtPrinterHelper &Helper,
4917  const CXXCtorInitializer *I) {
4918  if (I->isBaseInitializer())
4919  OS << I->getBaseClass()->getAsCXXRecordDecl()->getName();
4920  else if (I->isDelegatingInitializer())
4922  else
4923  OS << I->getAnyMember()->getName();
4924  OS << "(";
4925  if (Expr *IE = I->getInit())
4926  IE->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
4927  OS << ")";
4928 
4929  if (I->isBaseInitializer())
4930  OS << " (Base initializer)";
4931  else if (I->isDelegatingInitializer())
4932  OS << " (Delegating initializer)";
4933  else
4934  OS << " (Member initializer)";
4935 }
4936 
4937 static void print_construction_context(raw_ostream &OS,
4938  StmtPrinterHelper &Helper,
4939  const ConstructionContext *CC) {
4940  const Stmt *S1 = nullptr, *S2 = nullptr;
4941  switch (CC->getKind()) {
4943  OS << ", ";
4944  const auto *SICC = cast<SimpleConstructorInitializerConstructionContext>(CC);
4945  print_initializer(OS, Helper, SICC->getCXXCtorInitializer());
4946  break;
4947  }
4949  OS << ", ";
4950  const auto *CICC =
4951  cast<CXX17ElidedCopyConstructorInitializerConstructionContext>(CC);
4952  print_initializer(OS, Helper, CICC->getCXXCtorInitializer());
4953  S2 = CICC->getCXXBindTemporaryExpr();
4954  break;
4955  }
4957  const auto *SDSCC = cast<SimpleVariableConstructionContext>(CC);
4958  S1 = SDSCC->getDeclStmt();
4959  break;
4960  }
4962  const auto *CDSCC = cast<CXX17ElidedCopyVariableConstructionContext>(CC);
4963  S1 = CDSCC->getDeclStmt();
4964  S2 = CDSCC->getCXXBindTemporaryExpr();
4965  break;
4966  }
4968  const auto *NECC = cast<NewAllocatedObjectConstructionContext>(CC);
4969  S1 = NECC->getCXXNewExpr();
4970  break;
4971  }
4973  const auto *RSCC = cast<SimpleReturnedValueConstructionContext>(CC);
4974  S1 = RSCC->getReturnStmt();
4975  break;
4976  }
4978  const auto *RSCC =
4979  cast<CXX17ElidedCopyReturnedValueConstructionContext>(CC);
4980  S1 = RSCC->getReturnStmt();
4981  S2 = RSCC->getCXXBindTemporaryExpr();
4982  break;
4983  }
4985  const auto *TOCC = cast<TemporaryObjectConstructionContext>(CC);
4986  S1 = TOCC->getCXXBindTemporaryExpr();
4987  S2 = TOCC->getMaterializedTemporaryExpr();
4988  break;
4989  }
4990  }
4991  if (S1) {
4992  OS << ", ";
4993  Helper.handledStmt(const_cast<Stmt *>(S1), OS);
4994  }
4995  if (S2) {
4996  OS << ", ";
4997  Helper.handledStmt(const_cast<Stmt *>(S2), OS);
4998  }
4999 }
5000 
5001 static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
5002  const CFGElement &E) {
5003  if (Optional<CFGStmt> CS = E.getAs<CFGStmt>()) {
5004  const Stmt *S = CS->getStmt();
5005  assert(S != nullptr && "Expecting non-null Stmt");
5006 
5007  // special printing for statement-expressions.
5008  if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) {
5009  const CompoundStmt *Sub = SE->getSubStmt();
5010 
5011  auto Children = Sub->children();
5012  if (Children.begin() != Children.end()) {
5013  OS << "({ ... ; ";
5014  Helper.handledStmt(*SE->getSubStmt()->body_rbegin(),OS);
5015  OS << " })\n";
5016  return;
5017  }
5018  }
5019  // special printing for comma expressions.
5020  if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) {
5021  if (B->getOpcode() == BO_Comma) {
5022  OS << "... , ";
5023  Helper.handledStmt(B->getRHS(),OS);
5024  OS << '\n';
5025  return;
5026  }
5027  }
5028  S->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
5029 
5030  if (auto VTC = E.getAs<CFGCXXRecordTypedCall>()) {
5031  if (isa<CXXOperatorCallExpr>(S))
5032  OS << " (OperatorCall)";
5033  OS << " (CXXRecordTypedCall";
5034  print_construction_context(OS, Helper, VTC->getConstructionContext());
5035  OS << ")";
5036  } else if (isa<CXXOperatorCallExpr>(S)) {
5037  OS << " (OperatorCall)";
5038  } else if (isa<CXXBindTemporaryExpr>(S)) {
5039  OS << " (BindTemporary)";
5040  } else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) {
5041  OS << " (CXXConstructExpr";
5043  print_construction_context(OS, Helper, CE->getConstructionContext());
5044  }
5045  OS << ", " << CCE->getType().getAsString() << ")";
5046  } else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) {
5047  OS << " (" << CE->getStmtClassName() << ", "
5048  << CE->getCastKindName()
5049  << ", " << CE->getType().getAsString()
5050  << ")";
5051  }
5052 
5053  // Expressions need a newline.
5054  if (isa<Expr>(S))
5055  OS << '\n';
5056  } else if (Optional<CFGInitializer> IE = E.getAs<CFGInitializer>()) {
5057  print_initializer(OS, Helper, IE->getInitializer());
5058  OS << '\n';
5059  } else if (Optional<CFGAutomaticObjDtor> DE =
5060  E.getAs<CFGAutomaticObjDtor>()) {
5061  const VarDecl *VD = DE->getVarDecl();
5062  Helper.handleDecl(VD, OS);
5063 
5064  const Type* T = VD->getType().getTypePtr();
5065  if (const ReferenceType* RT = T->getAs<ReferenceType>())
5066  T = RT->getPointeeType().getTypePtr();
5067  T = T->getBaseElementTypeUnsafe();
5068 
5069  OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()";
5070  OS << " (Implicit destructor)\n";
5071  } else if (Optional<CFGLifetimeEnds> DE = E.getAs<CFGLifetimeEnds>()) {
5072  const VarDecl *VD = DE->getVarDecl();
5073  Helper.handleDecl(VD, OS);
5074 
5075  OS << " (Lifetime ends)\n";
5076  } else if (Optional<CFGLoopExit> LE = E.getAs<CFGLoopExit>()) {
5077  const Stmt *LoopStmt = LE->getLoopStmt();
5078  OS << LoopStmt->getStmtClassName() << " (LoopExit)\n";
5079  } else if (Optional<CFGScopeBegin> SB = E.getAs<CFGScopeBegin>()) {
5080  OS << "CFGScopeBegin(";
5081  if (const VarDecl *VD = SB->getVarDecl())
5082  OS << VD->getQualifiedNameAsString();
5083  OS << ")\n";
5084  } else if (Optional<CFGScopeEnd> SE = E.getAs<CFGScopeEnd>()) {
5085  OS << "CFGScopeEnd(";
5086  if (const VarDecl *VD = SE->getVarDecl())
5087  OS << VD->getQualifiedNameAsString();
5088  OS << ")\n";
5089  } else if (Optional<CFGNewAllocator> NE = E.getAs<CFGNewAllocator>()) {
5090  OS << "CFGNewAllocator(";
5091  if (const CXXNewExpr *AllocExpr = NE->getAllocatorExpr())
5092  AllocExpr->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
5093  OS << ")\n";
5094  } else if (Optional<CFGDeleteDtor> DE = E.getAs<CFGDeleteDtor>()) {
5095  const CXXRecordDecl *RD = DE->getCXXRecordDecl();
5096  if (!RD)
5097  return;
5098  CXXDeleteExpr *DelExpr =
5099  const_cast<CXXDeleteExpr*>(DE->getDeleteExpr());
5100  Helper.handledStmt(cast<Stmt>(DelExpr->getArgument()), OS);
5101  OS << "->~" << RD->getName().str() << "()";
5102  OS << " (Implicit destructor)\n";
5103  } else if (Optional<CFGBaseDtor> BE = E.getAs<CFGBaseDtor>()) {
5104  const CXXBaseSpecifier *BS = BE->getBaseSpecifier();
5105  OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()";
5106  OS << " (Base object destructor)\n";
5107  } else if (Optional<CFGMemberDtor> ME = E.getAs<CFGMemberDtor>()) {
5108  const FieldDecl *FD = ME->getFieldDecl();
5109  const Type *T = FD->getType()->getBaseElementTypeUnsafe();
5110  OS << "this->" << FD->getName();
5111  OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()";
5112  OS << " (Member object destructor)\n";
5113  } else if (Optional<CFGTemporaryDtor> TE = E.getAs<CFGTemporaryDtor>()) {
5114  const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr();
5115  OS << "~";
5116  BT->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
5117  OS << "() (Temporary object destructor)\n";
5118  }
5119 }
5120 
5121 static void print_block(raw_ostream &OS, const CFG* cfg,
5122  const CFGBlock &B,
5123  StmtPrinterHelper &Helper, bool print_edges,
5124  bool ShowColors) {
5125  Helper.setBlockID(B.getBlockID());
5126 
5127  // Print the header.
5128  if (ShowColors)
5129  OS.changeColor(raw_ostream::YELLOW, true);
5130 
5131  OS << "\n [B" << B.getBlockID();
5132 
5133  if (&B == &cfg->getEntry())
5134  OS << " (ENTRY)]\n";
5135  else if (&B == &cfg->getExit())
5136  OS << " (EXIT)]\n";
5137  else if (&B == cfg->getIndirectGotoBlock())
5138  OS << " (INDIRECT GOTO DISPATCH)]\n";
5139  else if (B.hasNoReturnElement())
5140  OS << " (NORETURN)]\n";
5141  else
5142  OS << "]\n";
5143 
5144  if (ShowColors)
5145  OS.resetColor();
5146 
5147  // Print the label of this block.
5148  if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) {
5149  if (print_edges)
5150  OS << " ";
5151 
5152  if (LabelStmt *L = dyn_cast<LabelStmt>(Label))
5153  OS << L->getName();
5154  else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) {
5155  OS << "case ";
5156  if (C->getLHS())
5157  C->getLHS()->printPretty(OS, &Helper,
5158  PrintingPolicy(Helper.getLangOpts()));
5159  if (C->getRHS()) {
5160  OS << " ... ";
5161  C->getRHS()->printPretty(OS, &Helper,
5162  PrintingPolicy(Helper.getLangOpts()));
5163  }
5164  } else if (isa<DefaultStmt>(Label))
5165  OS << "default";
5166  else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) {
5167  OS << "catch (";
5168  if (CS->getExceptionDecl())
5169  CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper.getLangOpts()),
5170  0);
5171  else
5172  OS << "...";
5173  OS << ")";
5174  } else if (SEHExceptStmt *ES = dyn_cast<SEHExceptStmt>(Label)) {
5175  OS << "__except (";
5176  ES->getFilterExpr()->printPretty(OS, &Helper,
5177  PrintingPolicy(Helper.getLangOpts()), 0);
5178  OS << ")";
5179  } else
5180  llvm_unreachable("Invalid label statement in CFGBlock.");
5181 
5182  OS << ":\n";
5183  }
5184 
5185  // Iterate through the statements in the block and print them.
5186  unsigned j = 1;
5187 
5188  for (CFGBlock::const_iterator I = B.begin(), E = B.end() ;
5189  I != E ; ++I, ++j ) {
5190  // Print the statement # in the basic block and the statement itself.
5191  if (print_edges)
5192  OS << " ";
5193 
5194  OS << llvm::format("%3d", j) << ": ";
5195 
5196  Helper.setStmtID(j);
5197 
5198  print_elem(OS, Helper, *I);
5199  }
5200 
5201  // Print the terminator of this block.
5202  if (B.getTerminator()) {
5203  if (ShowColors)
5204  OS.changeColor(raw_ostream::GREEN);
5205 
5206  OS << " T: ";
5207 
5208  Helper.setBlockID(-1);
5209 
5210  PrintingPolicy PP(Helper.getLangOpts());
5211  CFGBlockTerminatorPrint TPrinter(OS, &Helper, PP);
5212  TPrinter.print(B.getTerminator());
5213  OS << '\n';
5214 
5215  if (ShowColors)
5216  OS.resetColor();
5217  }
5218 
5219  if (print_edges) {
5220  // Print the predecessors of this block.
5221  if (!B.pred_empty()) {
5222  const raw_ostream::Colors Color = raw_ostream::BLUE;
5223  if (ShowColors)
5224  OS.changeColor(Color);
5225  OS << " Preds " ;
5226  if (ShowColors)
5227  OS.resetColor();
5228  OS << '(' << B.pred_size() << "):";
5229  unsigned i = 0;
5230 
5231  if (ShowColors)
5232  OS.changeColor(Color);
5233 
5234  for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end();
5235  I != E; ++I, ++i) {
5236  if (i % 10 == 8)
5237  OS << "\n ";
5238 
5239  CFGBlock *B = *I;
5240  bool Reachable = true;
5241  if (!B) {
5242  Reachable = false;
5243  B = I->getPossiblyUnreachableBlock();
5244  }
5245 
5246  OS << " B" << B->getBlockID();
5247  if (!Reachable)
5248  OS << "(Unreachable)";
5249  }
5250 
5251  if (ShowColors)
5252  OS.resetColor();
5253 
5254  OS << '\n';
5255  }
5256 
5257  // Print the successors of this block.
5258  if (!B.succ_empty()) {
5259  const raw_ostream::Colors Color = raw_ostream::MAGENTA;
5260  if (ShowColors)
5261  OS.changeColor(Color);
5262  OS << " Succs ";
5263  if (ShowColors)
5264  OS.resetColor();
5265  OS << '(' << B.succ_size() << "):";
5266  unsigned i = 0;
5267 
5268  if (ShowColors)
5269  OS.changeColor(Color);
5270 
5271  for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end();
5272  I != E; ++I, ++i) {
5273  if (i % 10 == 8)
5274  OS << "\n ";
5275 
5276  CFGBlock *B = *I;
5277 
5278  bool Reachable = true;
5279  if (!B) {
5280  Reachable = false;
5281  B = I->getPossiblyUnreachableBlock();
5282  }
5283 
5284  if (B) {
5285  OS << " B" << B->getBlockID();
5286  if (!Reachable)
5287  OS << "(Unreachable)";
5288  }
5289  else {
5290  OS << " NULL";
5291  }
5292  }
5293 
5294  if (ShowColors)
5295  OS.resetColor();
5296  OS << '\n';
5297  }
5298  }
5299 }
5300 
5301 /// dump - A simple pretty printer of a CFG that outputs to stderr.
5302 void CFG::dump(const LangOptions &LO, bool ShowColors) const {
5303  print(llvm::errs(), LO, ShowColors);
5304 }
5305 
5306 /// print - A simple pretty printer of a CFG that outputs to an ostream.
5307 void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const {
5308  StmtPrinterHelper Helper(this, LO);
5309 
5310  // Print the entry block.
5311  print_block(OS, this, getEntry(), Helper, true, ShowColors);
5312 
5313  // Iterate through the CFGBlocks and print them one by one.
5314  for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) {
5315  // Skip the entry block, because we already printed it.
5316  if (&(**I) == &getEntry() || &(**I) == &getExit())
5317  continue;
5318 
5319  print_block(OS, this, **I, Helper, true, ShowColors);
5320  }
5321 
5322  // Print the exit block.
5323  print_block(OS, this, getExit(), Helper, true, ShowColors);
5324  OS << '\n';
5325  OS.flush();
5326 }
5327 
5328 /// dump - A simply pretty printer of a CFGBlock that outputs to stderr.
5329 void CFGBlock::dump(const CFG* cfg, const LangOptions &LO,
5330  bool ShowColors) const {
5331  print(llvm::errs(), cfg, LO, ShowColors);
5332 }
5333 
5334 LLVM_DUMP_METHOD void CFGBlock::dump() const {
5335  dump(getParent(), LangOptions(), false);
5336 }
5337 
5338 /// print - A simple pretty printer of a CFGBlock that outputs to an ostream.
5339 /// Generally this will only be called from CFG::print.
5340 void CFGBlock::print(raw_ostream &OS, const CFG* cfg,
5341  const LangOptions &LO, bool ShowColors) const {
5342  StmtPrinterHelper Helper(cfg, LO);
5343  print_block(OS, cfg, *this, Helper, true, ShowColors);
5344  OS << '\n';
5345 }
5346 
5347 /// printTerminator - A simple pretty printer of the terminator of a CFGBlock.
5348 void CFGBlock::printTerminator(raw_ostream &OS,
5349  const LangOptions &LO) const {
5350  CFGBlockTerminatorPrint TPrinter(OS, nullptr, PrintingPolicy(LO));
5351  TPrinter.print(getTerminator());
5352 }
5353 
5355  Stmt *Terminator = this->Terminator;
5356  if (!Terminator)
5357  return nullptr;
5358 
5359  Expr *E = nullptr;
5360 
5361  switch (Terminator->getStmtClass()) {
5362  default:
5363  break;
5364 
5365  case Stmt::CXXForRangeStmtClass:
5366  E = cast<CXXForRangeStmt>(Terminator)->getCond();
5367  break;
5368 
5369  case Stmt::ForStmtClass:
5370  E = cast<ForStmt>(Terminator)->getCond();
5371  break;
5372 
5373  case Stmt::WhileStmtClass:
5374  E = cast<WhileStmt>(Terminator)->getCond();
5375  break;
5376 
5377  case Stmt::DoStmtClass:
5378  E = cast<DoStmt>(Terminator)->getCond();
5379  break;
5380 
5381  case Stmt::IfStmtClass:
5382  E = cast<IfStmt>(Terminator)->getCond();
5383  break;
5384 
5385  case Stmt::ChooseExprClass:
5386  E = cast<ChooseExpr>(Terminator)->getCond();
5387  break;
5388 
5389  case Stmt::IndirectGotoStmtClass:
5390  E = cast<IndirectGotoStmt>(Terminator)->getTarget();
5391  break;
5392 
5393  case Stmt::SwitchStmtClass:
5394  E = cast<SwitchStmt>(Terminator)->getCond();
5395  break;
5396 
5397  case Stmt::BinaryConditionalOperatorClass:
5398  E = cast<BinaryConditionalOperator>(Terminator)->getCond();
5399  break;
5400 
5401  case Stmt::ConditionalOperatorClass:
5402  E = cast<ConditionalOperator>(Terminator)->getCond();
5403  break;
5404 
5405  case Stmt::BinaryOperatorClass: // '&&' and '||'
5406  E = cast<BinaryOperator>(Terminator)->getLHS();
5407  break;
5408 
5409  case Stmt::ObjCForCollectionStmtClass:
5410  return Terminator;
5411  }
5412 
5413  if (!StripParens)
5414  return E;
5415 
5416  return E ? E->IgnoreParens() : nullptr;
5417 }
5418 
5419 //===----------------------------------------------------------------------===//
5420 // CFG Graphviz Visualization
5421 //===----------------------------------------------------------------------===//
5422 
5423 #ifndef NDEBUG
5424 static StmtPrinterHelper* GraphHelper;
5425 #endif
5426 
5427 void CFG::viewCFG(const LangOptions &LO) const {
5428 #ifndef NDEBUG
5429  StmtPrinterHelper H(this, LO);
5430  GraphHelper = &H;
5431  llvm::ViewGraph(this,"CFG");
5432  GraphHelper = nullptr;
5433 #endif
5434 }
5435 
5436 namespace llvm {
5437 
5438 template<>
5439 struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits {
5440  DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
5441 
5442  static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) {
5443 #ifndef NDEBUG
5444  std::string OutSStr;
5445  llvm::raw_string_ostream Out(OutSStr);
5446  print_block(Out,Graph, *Node, *GraphHelper, false, false);
5447  std::string& OutStr = Out.str();
5448 
5449  if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
5450 
5451  // Process string output to make it nicer...
5452  for (unsigned i = 0; i != OutStr.length(); ++i)
5453  if (OutStr[i] == '\n') { // Left justify
5454  OutStr[i] = '\\';
5455  OutStr.insert(OutStr.begin()+i+1, 'l');
5456  }
5457 
5458  return OutStr;
5459 #else
5460  return {};
5461 #endif
5462  }
5463 };
5464 
5465 } // namespace llvm
Expr * getInc()
Definition: Stmt.h:1257
unsigned getNumSemanticExprs() const
Definition: Expr.h:5064
bool isBaseInitializer() const
Determine whether this initializer is initializing a base class.
Definition: DeclCXX.h:2289
bool isNoReturn() const
Determines whether this function is known to be &#39;noreturn&#39;, through an attribute on its declaration o...
Definition: Decl.cpp:2865
Defines the clang::ASTContext interface.
const BlockDecl * getBlockDecl() const
Definition: Expr.h:4896
CFGNewAllocator - Represents C++ allocator call.
Definition: CFG.h:235
const CXXDestructorDecl * getDestructor() const
Definition: ExprCXX.h:1175
Represents a function declaration or definition.
Definition: Decl.h:1714
Expr * getInit() const
Get the initializer.
Definition: DeclCXX.h:2418
const Stmt * getElse() const
Definition: Stmt.h:989
CompoundStmt * getBlock() const
Definition: Stmt.h:1974
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:3842
pred_iterator pred_end()
Definition: CFG.h:733
PointerType - C99 6.7.5.1 - Pointer Declarators.
Definition: Type.h:2354
QualType getPointeeType() const
Definition: Type.h:2367
A (possibly-)qualified type.
Definition: Type.h:654
bool isBlockPointerType() const
Definition: Type.h:6036
base_class_range bases()
Definition: DeclCXX.h:796
Expr * getCond() const
Definition: Expr.h:3740
static SourceLocation GetEndLoc(Decl *D)
Definition: CFG.cpp:66
AdjacentBlocks::const_iterator const_pred_iterator
Definition: CFG.h:719
iterator beginScopeEndInsert(iterator I, size_t Cnt, BumpVectorContext &C)
Definition: CFG.h:972
const internal::VariadicAllOfMatcher< Stmt > stmt
Matches statements.
void print(raw_ostream &OS, const PrintingPolicy &Policy, const Twine &PlaceHolder=Twine(), unsigned Indentation=0) const
Definition: Type.h:990
bool operator==(CanQual< T > x, CanQual< U > y)
Expr * getCond()
Definition: Stmt.h:1147
DOTGraphTraits(bool isSimple=false)
Definition: CFG.cpp:5440
ElementList::iterator iterator
Definition: CFG.h:694
succ_iterator succ_begin()
Definition: CFG.h:750
CompoundStmt * getSubStmt()
Definition: Expr.h:3535
DominatorTree GraphTraits specialization so the DominatorTree can be iterable by generic graph iterat...
Definition: Dominators.h:30
bool isReachable() const
Definition: CFG.h:661
const DeclStmt * getConditionVariableDeclStmt() const
If this ForStmt has a condition variable, return the faux DeclStmt associated with the creation of th...
Definition: Stmt.h:1252
Stmt - This represents one statement.
Definition: Stmt.h:66
FunctionType - C99 6.7.5.3 - Function Declarators.
Definition: Type.h:3127
CXXCatchStmt * getHandler(unsigned i)
Definition: StmtCXX.h:104
CFGBlock & getEntry()
Definition: CFG.h:1091
IfStmt - This represents an if/then/else.
Definition: Stmt.h:949
QualType getPointeeType() const
If this is a pointer, ObjC object pointer, or block pointer, this returns the respective pointee...
Definition: Type.cpp:460
StorageClass getStorageClass() const
Returns the storage class as written in the source.
Definition: Decl.h:1017
void appendCXXRecordTypedCall(CallExpr *CE, const ConstructionContext *CC, BumpVectorContext &C)
Definition: CFG.h:881
void appendScopeEnd(const VarDecl *VD, const Stmt *S, BumpVectorContext &C)
Definition: CFG.h:907
C Language Family Type Representation.
bool isRecordType() const
Definition: Type.h:6101
Expr * getBase() const
Definition: Expr.h:2506
void prependScopeBegin(const VarDecl *VD, const Stmt *S, BumpVectorContext &C)
Definition: CFG.h:902
unsigned getBlockID() const
Definition: CFG.h:855
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:86
Stmt * getHandlerBlock() const
Definition: StmtCXX.h:52
static QualType getReferenceInitTemporaryType(ASTContext &Context, 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:1496
Opcode getOpcode() const
Definition: Expr.h:3057
StringRef P
void appendNewAllocator(CXXNewExpr *NE, BumpVectorContext &C)
Definition: CFG.h:892
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:5977
void appendLifetimeEnds(VarDecl *VD, Stmt *S, BumpVectorContext &C)
Definition: CFG.h:931
The base class of the type hierarchy.
Definition: Type.h:1420
Represents Objective-C&#39;s @throw statement.
Definition: StmtObjC.h:313
CFGDeleteDtor - Represents C++ object destructor generated from a call to delete. ...
Definition: CFG.h:405
Represents an array type, per C99 6.7.5.2 - Array Declarators.
Definition: Type.h:2629
iterator begin()
Definition: CFG.h:702
Represents a call to a C++ constructor.
Definition: ExprCXX.h:1239
unsigned IgnoreDefaultsWithCoveredEnums
Definition: CFG.h:778
Represents a C++ constructor within a class.
Definition: DeclCXX.h:2448
Represents a prvalue temporary that is written into memory so that a reference can bind to it...
Definition: ExprCXX.h:4039
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:911
bool isCompleteDefinition() const
Return true if this decl has its body fully specified.
Definition: Decl.h:3157
VarDecl * getConditionVariable() const
Retrieve the variable declared in this "while" statement, if any.
Definition: Stmt.cpp:901
unsigned succ_size() const
Definition: CFG.h:768
const CXXDestructorDecl * getDestructorDecl(ASTContext &astContext) const
Definition: CFG.cpp:4576
Stmt * getSubStmt()
Definition: Stmt.h:830
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:1847
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:6397
CFGBlock * getReachableBlock() const
Get the reachable block, if one exists.
Definition: CFG.h:638
const char * getName() const
Definition: Stmt.cpp:333
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:5001
A C++ throw-expression (C++ [except.throw]).
Definition: ExprCXX.h:985
Represents an expression – generally a full-expression – that introduces cleanups to be run at the ...
Definition: ExprCXX.h:3003
static bool isAssignmentOp(Opcode Opc)
Definition: Expr.h:3139
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:867
const Stmt * getSubStmt() const
Definition: StmtObjC.h:356
const char * getStmtClassName() const
Definition: Stmt.cpp:75
CFGCXXRecordTypedCall - Represents a function call that returns a C++ object by value.
Definition: CFG.h:178
LabelStmt - Represents a label, which has a substatement.
Definition: Stmt.h:858
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:772
Stmt * getBody()
Definition: Stmt.h:1195
CFGBlock * getPossiblyUnreachableBlock() const
Get the potentially unreachable block.
Definition: CFG.h:643
void print(raw_ostream &Out, unsigned Indentation=0, bool PrintInstantiation=false) const
QualType getPointeeType() const
Definition: Type.h:2471
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:150
void setLoopTarget(const Stmt *loopTarget)
Definition: CFG.h:836
static std::string getNodeLabel(const CFGBlock *Node, const CFG *Graph)
Definition: CFG.cpp:5442
field_range fields() const
Definition: Decl.h:3764
Represents a member of a struct/union/class.
Definition: Decl.h:2521
TypeSourceInfo * getTypeSourceInfo() const
Returns the declarator information for a base class or delegating initializer.
Definition: DeclCXX.h:2350
iterator insertAutomaticObjDtor(iterator I, VarDecl *VD, Stmt *S)
Definition: CFG.h:951
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:5348
CFGAutomaticObjDtor - Represents C++ object destructor implicitly generated for automatic object or t...
Definition: CFG.h:379
const Expr * getRetValue() const
Definition: Stmt.cpp:928
void appendAutomaticObjDtor(VarDecl *VD, Stmt *S, BumpVectorContext &C)
Definition: CFG.h:927
bool isReferenceType() const
Definition: Type.h:6040
const CXXConstructExpr * getConstructExpr() const
Returns the CXXConstructExpr from this new-expression, or null.
Definition: ExprCXX.h:1998
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:1099
Expr * getSubExpr()
Definition: Expr.h:2792
void setTerminator(CFGTerminator Term)
Definition: CFG.h:834
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:1077
Represents Objective-C&#39;s @catch statement.
Definition: StmtObjC.h:74
AdjacentBlocks::const_iterator const_succ_iterator
Definition: CFG.h:726
IndirectGotoStmt - This represents an indirect goto.
Definition: Stmt.h:1328
Describes an C or C++ initializer list.
Definition: Expr.h:3903
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:1952
ForStmt - This represents a &#39;for (init;cond;inc)&#39; stmt.
Definition: Stmt.h:1223
APValue Val
Val - This is the value the expression can be folded to.
Definition: Expr.h:573
LabelDecl * getDecl() const
Definition: Stmt.h:875
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:1728
Expr * getInitializer()
The initializer of this new-expression.
Definition: ExprCXX.h:1990
Stmt * getBody()
Definition: Stmt.h:1258
CFGCallback * Observer
Definition: CFG.h:1015
child_range children()
Definition: Stmt.cpp:227
A builtin binary operation expression such as "x + y" or "x <= y".
Definition: Expr.h:3016
Stmt * getInit()
Definition: Stmt.h:1237
CXXForRangeStmt - This represents C++0x [stmt.ranged]&#39;s ranged for statement, represented as &#39;for (ra...
Definition: StmtCXX.h:128
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:5340
void printPretty(raw_ostream &OS, PrinterHelper *Helper, const PrintingPolicy &Policy, unsigned Indentation=0, const ASTContext *Context=nullptr) const
Scope - A scope is a transient data structure that is used while parsing the program.
Definition: Scope.h:40
const Type * getTypePtr() const
Retrieves a pointer to the underlying (unqualified) type.
Definition: Type.h:5804
void appendLoopExit(const Stmt *LoopStmt, BumpVectorContext &C)
Definition: CFG.h:935
Expr * getCond()
Definition: Stmt.h:1256
bool isInt() const
Definition: APValue.h:234
CastExpr - Base class for type casts, including both implicit casts (ImplicitCastExpr) and explicit c...
Definition: Expr.h:2739
Represents binding an expression to a temporary.
Definition: ExprCXX.h:1196
CXXTemporary * getTemporary()
Definition: ExprCXX.h:1215
FieldDecl * getAnyMember() const
Definition: DeclCXX.h:2362
A C++ lambda expression, which produces a function object (of unspecified type) that can be invoked l...
Definition: ExprCXX.h:1583
bool hasTrivialDestructor() const
Determine whether this class has a trivial destructor (C++ [class.dtor]p3)
Definition: DeclCXX.h:1453
bool isTypeDependent() const
isTypeDependent - Determines whether this expression is type-dependent (C++ [temp.dep.expr]), which means that its type could change from one template instantiation to the next.
Definition: Expr.h:167
child_range children()
Definition: Stmt.h:707
CXXDestructorDecl * getDestructor() const
Returns the destructor decl for this class.
Definition: DeclCXX.cpp:1659
VarDecl * getConditionVariable() const
Retrieve the variable declared in this "for" statement, if any.
Definition: Stmt.cpp:839
bool getNoReturn() const
Definition: Type.h:3198
Stmt * getInit()
Definition: Stmt.h:982
arg_iterator placement_arg_end()
Definition: ExprCXX.h:2029
Iterator for iterating over Stmt * arrays that contain only Expr *.
Definition: Stmt.h:343
llvm::DenseMap< const Stmt *, const CFGBlock * > ForcedBlkExprs
Definition: CFG.h:1012
CFGBlockListTy::const_iterator const_iterator
Definition: CFG.h:1069
CFG * getParent() const
Definition: CFG.h:857
void appendConstructor(CXXConstructExpr *CE, const ConstructionContext *CC, BumpVectorContext &C)
Definition: CFG.h:876
CompoundStmt - This represents a group of statements like { stmt stmt }.
Definition: Stmt.h:609
CXXRecordDecl * getAsCXXRecordDecl() const
Retrieves the CXXRecordDecl that this type refers to, either because the type is a RecordType or beca...
Definition: Type.cpp:1590
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3348
bool isDelegatingInitializer() const
Determine whether this initializer is creating a delegating constructor.
Definition: DeclCXX.h:2317
UnaryExprOrTypeTraitExpr - expression with either a type or (unevaluated) expression operand...
Definition: Expr.h:2056
void appendBaseDtor(const CXXBaseSpecifier *BS, BumpVectorContext &C)
Definition: CFG.h:915
static bool shouldAddCase(bool &switchExclusivelyCovered, const Expr::EvalResult *switchCond, const CaseStmt *CS, ASTContext &Ctx)
Definition: CFG.cpp:3851
CFGBlock - Represents a single basic block in a source-level CFG.
Definition: CFG.h:548
const DeclStmt * getConditionVariableDeclStmt() const
If this IfStmt has a condition variable, return the faux DeclStmt associated with the creation of tha...
Definition: Stmt.h:978
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:4633
Expr - This represents one expression.
Definition: Expr.h:106
Defines the clang::LangOptions interface.
Stmt * getTerminatorCondition(bool StripParens=true)
Definition: CFG.cpp:5354
static std::tuple< const DeclRefExpr *, BinaryOperatorKind, const Expr * > tryNormalizeBinaryOperator(const BinaryOperator *B)
Tries to interpret a binary operator into Decl Op Expr form, if Expr is an integer literal or an enum...
Definition: CFG.cpp:90
DeclStmt * getEndStmt()
Definition: StmtCXX.h:158
SourceLocation End
std::string Label
CFG - Represents a source-level, intra-procedural CFG that represents the control-flow of a Stmt...
Definition: CFG.h:1002
const FunctionProtoType * T
Represents a C++ functional cast expression that builds a temporary object.
Definition: ExprCXX.h:1533
const Stmt * getThen() const
Definition: Stmt.h:987
BlockExpr - Adaptor class for mixing a BlockDecl with expressions.
Definition: Expr.h:4882
Represents a C++ destructor within a class.
Definition: DeclCXX.h:2671
bool succ_empty() const
Definition: CFG.h:769
VarDecl * getExceptionDecl() const
Definition: StmtCXX.h:50
unsigned getNumInits() const
Definition: Expr.h:3933
const Expr * getCallee() const
Definition: Expr.h:2274
CFGConstructor - Represents C++ constructor call.
Definition: CFG.h:150
QualType getArgumentType() const
Definition: Expr.h:2093
#define bool
Definition: stdbool.h:31
Stmt * getBody()
Definition: Stmt.h:1150
const CompoundStmt * getSynchBody() const
Definition: StmtObjC.h:282
ElementList::const_iterator const_iterator
Definition: CFG.h:695
Expr * getRHS()
Definition: Stmt.h:781
bool isTemporaryDtorsBranch() const
Definition: CFG.h:509
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:675
QualType getType() const
Definition: Expr.h:128
static void print_initializer(raw_ostream &OS, StmtPrinterHelper &Helper, const CXXCtorInitializer *I)
Definition: CFG.cpp:4916
LabelDecl * getLabel() const
Definition: Stmt.h:1306
StorageDuration getStorageDuration() const
Retrieve the storage duration for the materialized temporary.
Definition: ExprCXX.h:4083
ReturnStmt - This represents a return, optionally of an expression: return; return 4;...
Definition: Stmt.h:1433
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:1733
static bool CanThrow(Expr *E, ASTContext &Ctx)
Definition: CFG.cpp:2342
const Type * getBaseElementTypeUnsafe() const
Get the base element type of this type, potentially discarding type qualifiers.
Definition: Type.h:6355
ValueDecl * getDecl()
Definition: Expr.h:1057
CFGBaseDtor - Represents C++ object destructor implicitly generated for base object in destructor...
Definition: CFG.h:431
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:1219
bool isNull() const
Return true if this QualType doesn&#39;t point to a type yet.
Definition: Type.h:719
DoStmt - This represents a &#39;do/while&#39; stmt.
Definition: Stmt.h:1174
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:557
RecordDecl * getDecl() const
Definition: Type.h:4061
Expr * getArgument()
Definition: ExprCXX.h:2128
void appendStmt(Stmt *statement, BumpVectorContext &C)
Definition: CFG.h:872
CFGTerminator getTerminator()
Definition: CFG.h:839
OpaqueValueExpr - An expression referring to an opaque object of a fixed type and value class...
Definition: Expr.h:875
Kind
PseudoObjectExpr - An expression which accesses a pseudo-object l-value.
Definition: Expr.h:5000
Construction context is a linked list of multiple layers.
Encodes a location in the source.
Stmt * getLabel()
Definition: CFG.h:850
unsigned getNumHandlers() const
Definition: StmtCXX.h:103
Expr * getSubExpr() const
Definition: Expr.h:1760
Represents a C++ temporary.
Definition: ExprCXX.h:1164
const SwitchCase * getSwitchCaseList() const
Definition: Stmt.h:1067
Represents a new-expression for memory allocation and constructor calls, e.g: "new CXXNewExpr(foo)"...
Definition: ExprCXX.h:1845
Expr * getLHS()
Definition: Stmt.h:780
void setLabel(Stmt *Statement)
Definition: CFG.h:835
static std::unique_ptr< CFG > buildCFG(const Decl *D, Stmt *AST, ASTContext *C, const BuildOptions &BO)
buildCFG - Builds a CFG from an AST.
Definition: CFG.cpp:4569
iterator insertScopeEnd(iterator I, VarDecl *VD, Stmt *S)
Definition: CFG.h:976
DeclStmt - Adaptor class for mixing declarations with statements and expressions. ...
Definition: Stmt.h:499
bool PruneTriviallyFalseEdges
Definition: CFG.h:1016
reverse_body_iterator body_rend()
Definition: Stmt.h:681
QualType getBaseElementType(const ArrayType *VAT) const
Return the innermost element type of an array type.
const ConstantArrayType * getAsConstantArrayType(QualType T) const
Definition: ASTContext.h:2340
virtual void compareAlwaysTrue(const BinaryOperator *B, bool isAlwaysTrue)
Definition: CFG.h:990
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:5121
const ArrayType * getAsArrayType(QualType T) const
Type Query functions.
bool isArray() const
Definition: ExprCXX.h:1950
decl_iterator decl_begin()
Definition: Stmt.h:552
bool isValueDependent() const
isValueDependent - Determines whether this expression is value-dependent (C++ [temp.dep.constexpr]).
Definition: Expr.h:149
arg_range arguments()
Definition: Expr.h:2328
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:559
ImplicitCastExpr - Allows us to explicitly represent implicit type conversions, which have no direct ...
Definition: Expr.h:2853
static QualType findBoundMemberType(const Expr *expr)
Given an expression of bound-member type, find the type of the member.
Definition: Expr.cpp:2415
Expr ** getInits()
Retrieve the set of initializers.
Definition: Expr.h:3936
void appendScopeBegin(const VarDecl *VD, const Stmt *S, BumpVectorContext &C)
Definition: CFG.h:897
iterator begin()
Definition: CFG.h:1076
static bool isLogicalOp(Opcode Opc)
Definition: Expr.h:3136
static const Expr * tryTransformToIntOrEnumConstant(const Expr *E)
Helper for tryNormalizeBinaryOperator.
Definition: CFG.cpp:75
void dump() const
Definition: CFG.cpp:5334
succ_iterator succ_end()
Definition: CFG.h:751
StmtExpr - This is the GNU Statement Expression extension: ({int X=4; X;}).
Definition: Expr.h:3519
bool isArgumentType() const
Definition: Expr.h:2092
Represents end of a scope implicitly generated by the compiler after the last Stmt in a CompoundStmt&#39;...
Definition: CFG.h:331
const DeclStmt * getConditionVariableDeclStmt() const
If this WhileStmt has a condition variable, return the faux DeclStmt associated with the creation of ...
Definition: Stmt.h:1143
static bool isCXXRecordTypedCall(CallExpr *CE, const ASTContext &ACtx)
Returns true when call expression CE needs to be represented by CFGCXXRecordTypedCall, as opposed to a regular CFGStmt.
Definition: CFG.h:182
Optional< T > getAs() const
Convert to the specified CFGElement type, returning None if this CFGElement is not of the desired typ...
Definition: CFG.h:109
Expr * getLHS() const
Definition: Expr.h:3060
Defines various enumerations that describe declaration and type specifiers.
AddrLabelExpr - The GNU address of label extension, representing &&label.
Definition: Expr.h:3475
ast_type_traits::DynTypedNode Node
pred_iterator pred_begin()
Definition: CFG.h:732
OpaqueValueExpr * getOpaqueValue() const
getOpaqueValue - Return the opaque value placeholder.
Definition: Expr.h:3416
VarDecl * getConditionVariable() const
Retrieve the variable declared in this "if" statement, if any.
Definition: Stmt.cpp:804
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:1262
EvalResult is a struct with detailed info about an evaluated expression.
Definition: Expr.h:571
Represents a delete expression for memory deallocation and destructor calls, e.g. ...
Definition: ExprCXX.h:2074
ArrayRef< Capture > captures() const
Definition: Decl.h:3968
iterator beginAutomaticObjDtorsInsert(iterator I, size_t Cnt, BumpVectorContext &C)
Definition: CFG.h:946
virtual void compareBitwiseEquality(const BinaryOperator *B, bool isAlwaysTrue)
Definition: CFG.h:991
FunctionDecl * getDirectCallee()
If the callee is a FunctionDecl, return it. Otherwise return 0.
Definition: Expr.cpp:1217
const Stmt * stripLabelLikeStatements() const
Strip off all label-like statements.
Definition: Stmt.cpp:155
static const VariableArrayType * FindVA(const Type *t)
Definition: CFG.cpp:1221
const Expr * getInit() const
Definition: Decl.h:1217
unsigned pred_size() const
Definition: CFG.h:771
StmtClass getStmtClass() const
Definition: Stmt.h:389
static StmtPrinterHelper * GraphHelper
Definition: CFG.cpp:5424
void appendDeleteDtor(CXXRecordDecl *RD, CXXDeleteExpr *DE, BumpVectorContext &C)
Definition: CFG.h:939
const CXXRecordDecl * getParent() const
Returns the parent of this method declaration, which is the class in which this method is defined...
Definition: DeclCXX.h:2136
bool isAnyDestructorNoReturn() const
Returns true if the class destructor, or any implicitly invoked destructors are marked noreturn...
Definition: DeclCXX.cpp:1672
const Type * getBaseClass() const
If this is a base class initializer, returns the type of the base class.
Definition: DeclCXX.cpp:2214
SEHExceptStmt * getExceptHandler() const
Returns 0 if not defined.
Definition: Stmt.cpp:948
const Decl * getSingleDecl() const
Definition: Stmt.h:516
FunctionType::ExtInfo getFunctionExtInfo(const Type &t)
Definition: Type.h:5929
const Expr * getSynchExpr() const
Definition: StmtObjC.h:290
void appendMemberDtor(FieldDecl *FD, BumpVectorContext &C)
Definition: CFG.h:919
void appendInitializer(CXXCtorInitializer *initializer, BumpVectorContext &C)
Definition: CFG.h:887
This class represents a potential adjacent block in the CFG.
Definition: CFG.h:619
bool isSingleDecl() const
isSingleDecl - This method returns true if this DeclStmt refers to a single Decl. ...
Definition: Stmt.h:512
Represents the point where the lifetime of an automatic object ends.
Definition: CFG.h:280
Stmt * getStmt()
Definition: CFG.h:506
Expr * IgnoreParenImpCasts() LLVM_READONLY
IgnoreParenImpCasts - Ignore parentheses and implicit casts.
Definition: Expr.cpp:2557
const Stmt * getBody() const
Definition: Stmt.h:1066
llvm::APInt getValue() const
Definition: Expr.h:1295
Represents a __leave statement.
Definition: Stmt.h:2035
LabelDecl * getLabel() const
Definition: Expr.h:3497
SwitchStmt - This represents a &#39;switch&#39; stmt.
Definition: Stmt.h:1027
Pointer to a block type.
Definition: Type.h:2456
CFGBlock * getIndirectGotoBlock()
Definition: CFG.h:1096
A helper class that allows the use of isa/cast/dyncast to detect TagType objects of structs/unions/cl...
Definition: Type.h:4051
bool body_empty() const
Definition: Stmt.h:634
Represents Objective-C&#39;s collection statement.
Definition: StmtObjC.h:24
AbstractConditionalOperator - An abstract base class for ConditionalOperator and BinaryConditionalOpe...
Definition: Expr.h:3258
Represents a C++ base or member initializer.
Definition: DeclCXX.h:2223
reverse_decl_iterator decl_rend()
Definition: Stmt.h:563
Stmt * getInit()
Definition: Stmt.h:1062
iterator insertLifetimeEnds(iterator I, VarDecl *VD, Stmt *S)
Definition: CFG.h:964
Base for LValueReferenceType and RValueReferenceType.
Definition: Type.h:2490
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:5307
CanQualType BoundMemberTy
Definition: ASTContext.h:1015
decl_range decls()
Definition: Stmt.h:546
static void print_construction_context(raw_ostream &OS, StmtPrinterHelper &Helper, const ConstructionContext *CC)
Definition: CFG.cpp:4937
Represents a base class of a C++ class.
Definition: DeclCXX.h:192
static const ConstructionContextLayer * create(BumpVectorContext &C, TriggerTy Trigger, const ConstructionContextLayer *Parent=nullptr)
arg_iterator placement_arg_begin()
Definition: ExprCXX.h:2026
DeclStmt * getRangeStmt()
Definition: StmtCXX.h:154
Expr * getRHS() const
Definition: Expr.h:3744
SEHFinallyStmt * getFinallyHandler() const
Definition: Stmt.cpp:952
GotoStmt - This represents a direct goto.
Definition: Stmt.h:1294
A use of a default initializer in a constructor or in aggregate initialization.
Definition: ExprCXX.h:1113
Expr * getTarget()
Definition: Stmt.h:1348
unsigned IgnoreNullPredecessors
Definition: CFG.h:777
bool hasNoReturnElement() const
Definition: CFG.h:853
X
Add a minimal nested name specifier fixit hint to allow lookup of a tag name from an outer enclosing ...
Definition: SemaDecl.cpp:13503
void setHasNoReturnElement()
Definition: CFG.h:837
Expr * getCond()
Definition: Stmt.h:1192
Defines the C++ Decl subclasses, other than those for templates (found in DeclTemplate.h) and friends (in DeclFriend.h).
MemberExpr - [C99 6.5.2.3] Structure and Union Members.
Definition: Expr.h:2416
void viewCFG(const LangOptions &LO) const
Definition: CFG.cpp:5427
Defines the clang::SourceLocation class and associated facilities.
ConstructionContext&#39;s subclasses describe different ways of constructing an object in C++...
Represents a C++ struct/union/class.
Definition: DeclCXX.h:300
ContinueStmt - This represents a continue.
Definition: Stmt.h:1371
reverse_body_iterator body_rbegin()
Definition: Stmt.h:677
ChooseExpr - GNU builtin-in function __builtin_choose_expr.
Definition: Expr.h:3695
Expr * getFilterExpr() const
Definition: Stmt.h:1936
BinaryConditionalOperator - The GNU extension to the conditional operator which allows the middle ope...
Definition: Expr.h:3373
CXXCatchStmt - This represents a C++ catch block.
Definition: StmtCXX.h:29
Represents an explicit C++ type conversion that uses "functional" notation (C++ [expr.type.conv]).
Definition: ExprCXX.h:1471
bool operator!=(CanQual< T > x, CanQual< U > y)
WhileStmt - This represents a &#39;while&#39; stmt.
Definition: Stmt.h:1118
CFGElement - Represents a top-level expression in a basic block.
Definition: CFG.h:55
void addSuccessor(AdjacentBlock Succ, BumpVectorContext &C)
Adds a (potentially unreachable) successor block to the current block.
Definition: CFG.cpp:4653
unsigned kind
All of the diagnostics that can be emitted by the frontend.
Definition: DiagnosticIDs.h:61
CFGTerminator - Represents CFGBlock terminator statement.
Definition: CFG.h:498
CompoundStmt * getTryBlock()
Definition: StmtCXX.h:96
bool AddRichCXXConstructors
Definition: CFG.h:1027
CFGMemberDtor - Represents C++ object destructor implicitly generated for member object in destructor...
Definition: CFG.h:452
Represents Objective-C&#39;s @try ... @catch ... @finally statement.
Definition: StmtObjC.h:154
AdjacentBlock(CFGBlock *B, bool IsReachable)
Construct an AdjacentBlock with a possibly unreachable block.
Definition: CFG.cpp:4643
Full-expression storage duration (for temporaries).
Definition: Specifiers.h:275
CallExpr - Represents a function call (C99 6.5.2.2, C++ [expr.call]).
Definition: Expr.h:2234
void dump(const LangOptions &LO, bool ShowColors) const
dump - A simple pretty printer of a CFG that outputs to stderr.
Definition: CFG.cpp:5302
void appendTemporaryDtor(CXXBindTemporaryExpr *E, BumpVectorContext &C)
Definition: CFG.h:923
bool isBuiltinAssumeFalse(const ASTContext &Ctx) const
Return true if this is a call to __assume() or __builtin_assume() with a non-value-dependent constant...
Definition: Expr.cpp:2925
StringRef getName() const
Get the name of identifier for this declaration as a StringRef.
Definition: Decl.h:275
Expr * getLHS() const
Definition: Expr.h:3742
std::string getQualifiedNameAsString() const
Definition: Decl.cpp:1500
static Decl::Kind getKind(const Decl *D)
Definition: DeclBase.cpp:930
capture_init_iterator capture_init_end()
Retrieve the iterator pointing one past the last initialization argument for this lambda expression...
Definition: ExprCXX.h:1740
A reference to a declared variable, function, enum, etc.
Definition: Expr.h:972
Expr * getRHS() const
Definition: Expr.h:3062
unsigned IncludeNewlines
When true, include newlines after statements like "break", etc.
BreakStmt - This represents a break.
Definition: Stmt.h:1397
CFGInitializer - Represents C++ base or member initializer from constructor&#39;s initialization list...
Definition: CFG.h:215
Expr * getSemanticExpr(unsigned index)
Definition: Expr.h:5088
Stmt * getSubStmt()
Definition: Stmt.h:878