clang  9.0.0svn
CFG.cpp
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1 //===- CFG.cpp - Classes for representing and building CFGs ---------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines the CFG and CFGBuilder classes for representing and
10 // building Control-Flow Graphs (CFGs) from ASTs.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/Analysis/CFG.h"
15 #include "clang/AST/ASTContext.h"
16 #include "clang/AST/Attr.h"
17 #include "clang/AST/Decl.h"
18 #include "clang/AST/DeclBase.h"
19 #include "clang/AST/DeclCXX.h"
20 #include "clang/AST/DeclGroup.h"
21 #include "clang/AST/Expr.h"
22 #include "clang/AST/ExprCXX.h"
25 #include "clang/AST/Stmt.h"
26 #include "clang/AST/StmtCXX.h"
27 #include "clang/AST/StmtObjC.h"
28 #include "clang/AST/StmtVisitor.h"
29 #include "clang/AST/Type.h"
32 #include "clang/Basic/Builtins.h"
34 #include "clang/Basic/LLVM.h"
37 #include "clang/Basic/Specifiers.h"
38 #include "llvm/ADT/APInt.h"
39 #include "llvm/ADT/APSInt.h"
40 #include "llvm/ADT/ArrayRef.h"
41 #include "llvm/ADT/DenseMap.h"
42 #include "llvm/ADT/Optional.h"
43 #include "llvm/ADT/STLExtras.h"
44 #include "llvm/ADT/SetVector.h"
45 #include "llvm/ADT/SmallPtrSet.h"
46 #include "llvm/ADT/SmallVector.h"
47 #include "llvm/Support/Allocator.h"
48 #include "llvm/Support/Casting.h"
49 #include "llvm/Support/Compiler.h"
50 #include "llvm/Support/DOTGraphTraits.h"
51 #include "llvm/Support/ErrorHandling.h"
52 #include "llvm/Support/Format.h"
53 #include "llvm/Support/GraphWriter.h"
54 #include "llvm/Support/SaveAndRestore.h"
55 #include "llvm/Support/raw_ostream.h"
56 #include <cassert>
57 #include <memory>
58 #include <string>
59 #include <tuple>
60 #include <utility>
61 #include <vector>
62 
63 using namespace clang;
64 
66  if (VarDecl *VD = dyn_cast<VarDecl>(D))
67  if (Expr *Ex = VD->getInit())
68  return Ex->getSourceRange().getEnd();
69  return D->getLocation();
70 }
71 
72 /// Helper for tryNormalizeBinaryOperator. Attempts to extract an IntegerLiteral
73 /// or EnumConstantDecl from the given Expr. If it fails, returns nullptr.
74 static const Expr *tryTransformToIntOrEnumConstant(const Expr *E) {
75  E = E->IgnoreParens();
76  if (isa<IntegerLiteral>(E))
77  return E;
78  if (auto *DR = dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))
79  return isa<EnumConstantDecl>(DR->getDecl()) ? DR : nullptr;
80  return nullptr;
81 }
82 
83 /// Tries to interpret a binary operator into `Decl Op Expr` form, if Expr is
84 /// an integer literal or an enum constant.
85 ///
86 /// If this fails, at least one of the returned DeclRefExpr or Expr will be
87 /// null.
88 static std::tuple<const DeclRefExpr *, BinaryOperatorKind, const Expr *>
90  BinaryOperatorKind Op = B->getOpcode();
91 
92  const Expr *MaybeDecl = B->getLHS();
93  const Expr *Constant = tryTransformToIntOrEnumConstant(B->getRHS());
94  // Expr looked like `0 == Foo` instead of `Foo == 0`
95  if (Constant == nullptr) {
96  // Flip the operator
97  if (Op == BO_GT)
98  Op = BO_LT;
99  else if (Op == BO_GE)
100  Op = BO_LE;
101  else if (Op == BO_LT)
102  Op = BO_GT;
103  else if (Op == BO_LE)
104  Op = BO_GE;
105 
106  MaybeDecl = B->getRHS();
107  Constant = tryTransformToIntOrEnumConstant(B->getLHS());
108  }
109 
110  auto *D = dyn_cast<DeclRefExpr>(MaybeDecl->IgnoreParenImpCasts());
111  return std::make_tuple(D, Op, Constant);
112 }
113 
114 /// For an expression `x == Foo && x == Bar`, this determines whether the
115 /// `Foo` and `Bar` are either of the same enumeration type, or both integer
116 /// literals.
117 ///
118 /// It's an error to pass this arguments that are not either IntegerLiterals
119 /// or DeclRefExprs (that have decls of type EnumConstantDecl)
120 static bool areExprTypesCompatible(const Expr *E1, const Expr *E2) {
121  // User intent isn't clear if they're mixing int literals with enum
122  // constants.
123  if (isa<IntegerLiteral>(E1) != isa<IntegerLiteral>(E2))
124  return false;
125 
126  // Integer literal comparisons, regardless of literal type, are acceptable.
127  if (isa<IntegerLiteral>(E1))
128  return true;
129 
130  // IntegerLiterals are handled above and only EnumConstantDecls are expected
131  // beyond this point
132  assert(isa<DeclRefExpr>(E1) && isa<DeclRefExpr>(E2));
133  auto *Decl1 = cast<DeclRefExpr>(E1)->getDecl();
134  auto *Decl2 = cast<DeclRefExpr>(E2)->getDecl();
135 
136  assert(isa<EnumConstantDecl>(Decl1) && isa<EnumConstantDecl>(Decl2));
137  const DeclContext *DC1 = Decl1->getDeclContext();
138  const DeclContext *DC2 = Decl2->getDeclContext();
139 
140  assert(isa<EnumDecl>(DC1) && isa<EnumDecl>(DC2));
141  return DC1 == DC2;
142 }
143 
144 namespace {
145 
146 class CFGBuilder;
147 
148 /// The CFG builder uses a recursive algorithm to build the CFG. When
149 /// we process an expression, sometimes we know that we must add the
150 /// subexpressions as block-level expressions. For example:
151 ///
152 /// exp1 || exp2
153 ///
154 /// When processing the '||' expression, we know that exp1 and exp2
155 /// need to be added as block-level expressions, even though they
156 /// might not normally need to be. AddStmtChoice records this
157 /// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then
158 /// the builder has an option not to add a subexpression as a
159 /// block-level expression.
160 class AddStmtChoice {
161 public:
162  enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 };
163 
164  AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {}
165 
166  bool alwaysAdd(CFGBuilder &builder,
167  const Stmt *stmt) const;
168 
169  /// Return a copy of this object, except with the 'always-add' bit
170  /// set as specified.
171  AddStmtChoice withAlwaysAdd(bool alwaysAdd) const {
172  return AddStmtChoice(alwaysAdd ? AlwaysAdd : NotAlwaysAdd);
173  }
174 
175 private:
176  Kind kind;
177 };
178 
179 /// LocalScope - Node in tree of local scopes created for C++ implicit
180 /// destructor calls generation. It contains list of automatic variables
181 /// declared in the scope and link to position in previous scope this scope
182 /// began in.
183 ///
184 /// The process of creating local scopes is as follows:
185 /// - Init CFGBuilder::ScopePos with invalid position (equivalent for null),
186 /// - Before processing statements in scope (e.g. CompoundStmt) create
187 /// LocalScope object using CFGBuilder::ScopePos as link to previous scope
188 /// and set CFGBuilder::ScopePos to the end of new scope,
189 /// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points
190 /// at this VarDecl,
191 /// - For every normal (without jump) end of scope add to CFGBlock destructors
192 /// for objects in the current scope,
193 /// - For every jump add to CFGBlock destructors for objects
194 /// between CFGBuilder::ScopePos and local scope position saved for jump
195 /// target. Thanks to C++ restrictions on goto jumps we can be sure that
196 /// jump target position will be on the path to root from CFGBuilder::ScopePos
197 /// (adding any variable that doesn't need constructor to be called to
198 /// LocalScope can break this assumption),
199 ///
200 class LocalScope {
201 public:
202  friend class const_iterator;
203 
204  using AutomaticVarsTy = BumpVector<VarDecl *>;
205 
206  /// const_iterator - Iterates local scope backwards and jumps to previous
207  /// scope on reaching the beginning of currently iterated scope.
208  class const_iterator {
209  const LocalScope* Scope = nullptr;
210 
211  /// VarIter is guaranteed to be greater then 0 for every valid iterator.
212  /// Invalid iterator (with null Scope) has VarIter equal to 0.
213  unsigned VarIter = 0;
214 
215  public:
216  /// Create invalid iterator. Dereferencing invalid iterator is not allowed.
217  /// Incrementing invalid iterator is allowed and will result in invalid
218  /// iterator.
219  const_iterator() = default;
220 
221  /// Create valid iterator. In case when S.Prev is an invalid iterator and
222  /// I is equal to 0, this will create invalid iterator.
223  const_iterator(const LocalScope& S, unsigned I)
224  : Scope(&S), VarIter(I) {
225  // Iterator to "end" of scope is not allowed. Handle it by going up
226  // in scopes tree possibly up to invalid iterator in the root.
227  if (VarIter == 0 && Scope)
228  *this = Scope->Prev;
229  }
230 
231  VarDecl *const* operator->() const {
232  assert(Scope && "Dereferencing invalid iterator is not allowed");
233  assert(VarIter != 0 && "Iterator has invalid value of VarIter member");
234  return &Scope->Vars[VarIter - 1];
235  }
236 
237  const VarDecl *getFirstVarInScope() const {
238  assert(Scope && "Dereferencing invalid iterator is not allowed");
239  assert(VarIter != 0 && "Iterator has invalid value of VarIter member");
240  return Scope->Vars[0];
241  }
242 
243  VarDecl *operator*() const {
244  return *this->operator->();
245  }
246 
247  const_iterator &operator++() {
248  if (!Scope)
249  return *this;
250 
251  assert(VarIter != 0 && "Iterator has invalid value of VarIter member");
252  --VarIter;
253  if (VarIter == 0)
254  *this = Scope->Prev;
255  return *this;
256  }
257  const_iterator operator++(int) {
258  const_iterator P = *this;
259  ++*this;
260  return P;
261  }
262 
263  bool operator==(const const_iterator &rhs) const {
264  return Scope == rhs.Scope && VarIter == rhs.VarIter;
265  }
266  bool operator!=(const const_iterator &rhs) const {
267  return !(*this == rhs);
268  }
269 
270  explicit operator bool() const {
271  return *this != const_iterator();
272  }
273 
274  int distance(const_iterator L);
275  const_iterator shared_parent(const_iterator L);
276  bool pointsToFirstDeclaredVar() { return VarIter == 1; }
277  };
278 
279 private:
280  BumpVectorContext ctx;
281 
282  /// Automatic variables in order of declaration.
283  AutomaticVarsTy Vars;
284 
285  /// Iterator to variable in previous scope that was declared just before
286  /// begin of this scope.
287  const_iterator Prev;
288 
289 public:
290  /// Constructs empty scope linked to previous scope in specified place.
291  LocalScope(BumpVectorContext ctx, const_iterator P)
292  : ctx(std::move(ctx)), Vars(this->ctx, 4), Prev(P) {}
293 
294  /// Begin of scope in direction of CFG building (backwards).
295  const_iterator begin() const { return const_iterator(*this, Vars.size()); }
296 
297  void addVar(VarDecl *VD) {
298  Vars.push_back(VD, ctx);
299  }
300 };
301 
302 } // namespace
303 
304 /// distance - Calculates distance from this to L. L must be reachable from this
305 /// (with use of ++ operator). Cost of calculating the distance is linear w.r.t.
306 /// number of scopes between this and L.
307 int LocalScope::const_iterator::distance(LocalScope::const_iterator L) {
308  int D = 0;
309  const_iterator F = *this;
310  while (F.Scope != L.Scope) {
311  assert(F != const_iterator() &&
312  "L iterator is not reachable from F iterator.");
313  D += F.VarIter;
314  F = F.Scope->Prev;
315  }
316  D += F.VarIter - L.VarIter;
317  return D;
318 }
319 
320 /// Calculates the closest parent of this iterator
321 /// that is in a scope reachable through the parents of L.
322 /// I.e. when using 'goto' from this to L, the lifetime of all variables
323 /// between this and shared_parent(L) end.
324 LocalScope::const_iterator
325 LocalScope::const_iterator::shared_parent(LocalScope::const_iterator L) {
326  llvm::SmallPtrSet<const LocalScope *, 4> ScopesOfL;
327  while (true) {
328  ScopesOfL.insert(L.Scope);
329  if (L == const_iterator())
330  break;
331  L = L.Scope->Prev;
332  }
333 
334  const_iterator F = *this;
335  while (true) {
336  if (ScopesOfL.count(F.Scope))
337  return F;
338  assert(F != const_iterator() &&
339  "L iterator is not reachable from F iterator.");
340  F = F.Scope->Prev;
341  }
342 }
343 
344 namespace {
345 
346 /// Structure for specifying position in CFG during its build process. It
347 /// consists of CFGBlock that specifies position in CFG and
348 /// LocalScope::const_iterator that specifies position in LocalScope graph.
349 struct BlockScopePosPair {
350  CFGBlock *block = nullptr;
351  LocalScope::const_iterator scopePosition;
352 
353  BlockScopePosPair() = default;
354  BlockScopePosPair(CFGBlock *b, LocalScope::const_iterator scopePos)
355  : block(b), scopePosition(scopePos) {}
356 };
357 
358 /// TryResult - a class representing a variant over the values
359 /// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool,
360 /// and is used by the CFGBuilder to decide if a branch condition
361 /// can be decided up front during CFG construction.
362 class TryResult {
363  int X = -1;
364 
365 public:
366  TryResult() = default;
367  TryResult(bool b) : X(b ? 1 : 0) {}
368 
369  bool isTrue() const { return X == 1; }
370  bool isFalse() const { return X == 0; }
371  bool isKnown() const { return X >= 0; }
372 
373  void negate() {
374  assert(isKnown());
375  X ^= 0x1;
376  }
377 };
378 
379 } // namespace
380 
381 static TryResult bothKnownTrue(TryResult R1, TryResult R2) {
382  if (!R1.isKnown() || !R2.isKnown())
383  return TryResult();
384  return TryResult(R1.isTrue() && R2.isTrue());
385 }
386 
387 namespace {
388 
389 class reverse_children {
390  llvm::SmallVector<Stmt *, 12> childrenBuf;
392 
393 public:
394  reverse_children(Stmt *S);
395 
396  using iterator = ArrayRef<Stmt *>::reverse_iterator;
397 
398  iterator begin() const { return children.rbegin(); }
399  iterator end() const { return children.rend(); }
400 };
401 
402 } // namespace
403 
404 reverse_children::reverse_children(Stmt *S) {
405  if (CallExpr *CE = dyn_cast<CallExpr>(S)) {
406  children = CE->getRawSubExprs();
407  return;
408  }
409  switch (S->getStmtClass()) {
410  // Note: Fill in this switch with more cases we want to optimize.
411  case Stmt::InitListExprClass: {
412  InitListExpr *IE = cast<InitListExpr>(S);
413  children = llvm::makeArrayRef(reinterpret_cast<Stmt**>(IE->getInits()),
414  IE->getNumInits());
415  return;
416  }
417  default:
418  break;
419  }
420 
421  // Default case for all other statements.
422  for (Stmt *SubStmt : S->children())
423  childrenBuf.push_back(SubStmt);
424 
425  // This needs to be done *after* childrenBuf has been populated.
426  children = childrenBuf;
427 }
428 
429 namespace {
430 
431 /// CFGBuilder - This class implements CFG construction from an AST.
432 /// The builder is stateful: an instance of the builder should be used to only
433 /// construct a single CFG.
434 ///
435 /// Example usage:
436 ///
437 /// CFGBuilder builder;
438 /// std::unique_ptr<CFG> cfg = builder.buildCFG(decl, stmt1);
439 ///
440 /// CFG construction is done via a recursive walk of an AST. We actually parse
441 /// the AST in reverse order so that the successor of a basic block is
442 /// constructed prior to its predecessor. This allows us to nicely capture
443 /// implicit fall-throughs without extra basic blocks.
444 class CFGBuilder {
445  using JumpTarget = BlockScopePosPair;
446  using JumpSource = BlockScopePosPair;
447 
448  ASTContext *Context;
449  std::unique_ptr<CFG> cfg;
450 
451  // Current block.
452  CFGBlock *Block = nullptr;
453 
454  // Block after the current block.
455  CFGBlock *Succ = nullptr;
456 
457  JumpTarget ContinueJumpTarget;
458  JumpTarget BreakJumpTarget;
459  JumpTarget SEHLeaveJumpTarget;
460  CFGBlock *SwitchTerminatedBlock = nullptr;
461  CFGBlock *DefaultCaseBlock = nullptr;
462 
463  // This can point either to a try or a __try block. The frontend forbids
464  // mixing both kinds in one function, so having one for both is enough.
465  CFGBlock *TryTerminatedBlock = nullptr;
466 
467  // Current position in local scope.
468  LocalScope::const_iterator ScopePos;
469 
470  // LabelMap records the mapping from Label expressions to their jump targets.
471  using LabelMapTy = llvm::DenseMap<LabelDecl *, JumpTarget>;
472  LabelMapTy LabelMap;
473 
474  // A list of blocks that end with a "goto" that must be backpatched to their
475  // resolved targets upon completion of CFG construction.
476  using BackpatchBlocksTy = std::vector<JumpSource>;
477  BackpatchBlocksTy BackpatchBlocks;
478 
479  // A list of labels whose address has been taken (for indirect gotos).
480  using LabelSetTy = llvm::SmallSetVector<LabelDecl *, 8>;
481  LabelSetTy AddressTakenLabels;
482 
483  // Information about the currently visited C++ object construction site.
484  // This is set in the construction trigger and read when the constructor
485  // or a function that returns an object by value is being visited.
486  llvm::DenseMap<Expr *, const ConstructionContextLayer *>
487  ConstructionContextMap;
488 
489  using DeclsWithEndedScopeSetTy = llvm::SmallSetVector<VarDecl *, 16>;
490  DeclsWithEndedScopeSetTy DeclsWithEndedScope;
491 
492  bool badCFG = false;
493  const CFG::BuildOptions &BuildOpts;
494 
495  // State to track for building switch statements.
496  bool switchExclusivelyCovered = false;
497  Expr::EvalResult *switchCond = nullptr;
498 
499  CFG::BuildOptions::ForcedBlkExprs::value_type *cachedEntry = nullptr;
500  const Stmt *lastLookup = nullptr;
501 
502  // Caches boolean evaluations of expressions to avoid multiple re-evaluations
503  // during construction of branches for chained logical operators.
504  using CachedBoolEvalsTy = llvm::DenseMap<Expr *, TryResult>;
505  CachedBoolEvalsTy CachedBoolEvals;
506 
507 public:
508  explicit CFGBuilder(ASTContext *astContext,
509  const CFG::BuildOptions &buildOpts)
510  : Context(astContext), cfg(new CFG()), // crew a new CFG
511  ConstructionContextMap(), BuildOpts(buildOpts) {}
512 
513 
514  // buildCFG - Used by external clients to construct the CFG.
515  std::unique_ptr<CFG> buildCFG(const Decl *D, Stmt *Statement);
516 
517  bool alwaysAdd(const Stmt *stmt);
518 
519 private:
520  // Visitors to walk an AST and construct the CFG.
521  CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc);
522  CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc);
523  CFGBlock *VisitBreakStmt(BreakStmt *B);
524  CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc);
525  CFGBlock *VisitCaseStmt(CaseStmt *C);
526  CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc);
527  CFGBlock *VisitCompoundStmt(CompoundStmt *C);
528  CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C,
529  AddStmtChoice asc);
530  CFGBlock *VisitContinueStmt(ContinueStmt *C);
531  CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
532  AddStmtChoice asc);
533  CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S);
534  CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc);
535  CFGBlock *VisitCXXNewExpr(CXXNewExpr *DE, AddStmtChoice asc);
536  CFGBlock *VisitCXXDeleteExpr(CXXDeleteExpr *DE, AddStmtChoice asc);
537  CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S);
538  CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
539  AddStmtChoice asc);
540  CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
541  AddStmtChoice asc);
542  CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T);
543  CFGBlock *VisitCXXTryStmt(CXXTryStmt *S);
544  CFGBlock *VisitDeclStmt(DeclStmt *DS);
545  CFGBlock *VisitDeclSubExpr(DeclStmt *DS);
546  CFGBlock *VisitDefaultStmt(DefaultStmt *D);
547  CFGBlock *VisitDoStmt(DoStmt *D);
548  CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, AddStmtChoice asc);
549  CFGBlock *VisitForStmt(ForStmt *F);
550  CFGBlock *VisitGotoStmt(GotoStmt *G);
551  CFGBlock *VisitIfStmt(IfStmt *I);
552  CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc);
553  CFGBlock *VisitConstantExpr(ConstantExpr *E, AddStmtChoice asc);
554  CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I);
555  CFGBlock *VisitLabelStmt(LabelStmt *L);
556  CFGBlock *VisitBlockExpr(BlockExpr *E, AddStmtChoice asc);
557  CFGBlock *VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc);
558  CFGBlock *VisitLogicalOperator(BinaryOperator *B);
559  std::pair<CFGBlock *, CFGBlock *> VisitLogicalOperator(BinaryOperator *B,
560  Stmt *Term,
561  CFGBlock *TrueBlock,
562  CFGBlock *FalseBlock);
563  CFGBlock *VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *MTE,
564  AddStmtChoice asc);
565  CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc);
566  CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S);
567  CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S);
568  CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S);
569  CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S);
570  CFGBlock *VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S);
571  CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S);
572  CFGBlock *VisitObjCMessageExpr(ObjCMessageExpr *E, AddStmtChoice asc);
573  CFGBlock *VisitPseudoObjectExpr(PseudoObjectExpr *E);
574  CFGBlock *VisitReturnStmt(Stmt *S);
575  CFGBlock *VisitSEHExceptStmt(SEHExceptStmt *S);
576  CFGBlock *VisitSEHFinallyStmt(SEHFinallyStmt *S);
577  CFGBlock *VisitSEHLeaveStmt(SEHLeaveStmt *S);
578  CFGBlock *VisitSEHTryStmt(SEHTryStmt *S);
579  CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc);
580  CFGBlock *VisitSwitchStmt(SwitchStmt *S);
581  CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
582  AddStmtChoice asc);
583  CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc);
584  CFGBlock *VisitWhileStmt(WhileStmt *W);
585 
586  CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd);
587  CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc);
588  CFGBlock *VisitChildren(Stmt *S);
589  CFGBlock *VisitNoRecurse(Expr *E, AddStmtChoice asc);
590 
591  void maybeAddScopeBeginForVarDecl(CFGBlock *B, const VarDecl *VD,
592  const Stmt *S) {
593  if (ScopePos && (VD == ScopePos.getFirstVarInScope()))
594  appendScopeBegin(B, VD, S);
595  }
596 
597  /// When creating the CFG for temporary destructors, we want to mirror the
598  /// branch structure of the corresponding constructor calls.
599  /// Thus, while visiting a statement for temporary destructors, we keep a
600  /// context to keep track of the following information:
601  /// - whether a subexpression is executed unconditionally
602  /// - if a subexpression is executed conditionally, the first
603  /// CXXBindTemporaryExpr we encounter in that subexpression (which
604  /// corresponds to the last temporary destructor we have to call for this
605  /// subexpression) and the CFG block at that point (which will become the
606  /// successor block when inserting the decision point).
607  ///
608  /// That way, we can build the branch structure for temporary destructors as
609  /// follows:
610  /// 1. If a subexpression is executed unconditionally, we add the temporary
611  /// destructor calls to the current block.
612  /// 2. If a subexpression is executed conditionally, when we encounter a
613  /// CXXBindTemporaryExpr:
614  /// a) If it is the first temporary destructor call in the subexpression,
615  /// we remember the CXXBindTemporaryExpr and the current block in the
616  /// TempDtorContext; we start a new block, and insert the temporary
617  /// destructor call.
618  /// b) Otherwise, add the temporary destructor call to the current block.
619  /// 3. When we finished visiting a conditionally executed subexpression,
620  /// and we found at least one temporary constructor during the visitation
621  /// (2.a has executed), we insert a decision block that uses the
622  /// CXXBindTemporaryExpr as terminator, and branches to the current block
623  /// if the CXXBindTemporaryExpr was marked executed, and otherwise
624  /// branches to the stored successor.
625  struct TempDtorContext {
626  TempDtorContext() = default;
627  TempDtorContext(TryResult KnownExecuted)
628  : IsConditional(true), KnownExecuted(KnownExecuted) {}
629 
630  /// Returns whether we need to start a new branch for a temporary destructor
631  /// call. This is the case when the temporary destructor is
632  /// conditionally executed, and it is the first one we encounter while
633  /// visiting a subexpression - other temporary destructors at the same level
634  /// will be added to the same block and are executed under the same
635  /// condition.
636  bool needsTempDtorBranch() const {
637  return IsConditional && !TerminatorExpr;
638  }
639 
640  /// Remember the successor S of a temporary destructor decision branch for
641  /// the corresponding CXXBindTemporaryExpr E.
642  void setDecisionPoint(CFGBlock *S, CXXBindTemporaryExpr *E) {
643  Succ = S;
644  TerminatorExpr = E;
645  }
646 
647  const bool IsConditional = false;
648  const TryResult KnownExecuted = true;
649  CFGBlock *Succ = nullptr;
650  CXXBindTemporaryExpr *TerminatorExpr = nullptr;
651  };
652 
653  // Visitors to walk an AST and generate destructors of temporaries in
654  // full expression.
655  CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary,
656  TempDtorContext &Context);
657  CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E, TempDtorContext &Context);
658  CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E,
659  TempDtorContext &Context);
660  CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(
661  CXXBindTemporaryExpr *E, bool BindToTemporary, TempDtorContext &Context);
662  CFGBlock *VisitConditionalOperatorForTemporaryDtors(
663  AbstractConditionalOperator *E, bool BindToTemporary,
664  TempDtorContext &Context);
665  void InsertTempDtorDecisionBlock(const TempDtorContext &Context,
666  CFGBlock *FalseSucc = nullptr);
667 
668  // NYS == Not Yet Supported
669  CFGBlock *NYS() {
670  badCFG = true;
671  return Block;
672  }
673 
674  // Remember to apply the construction context based on the current \p Layer
675  // when constructing the CFG element for \p CE.
676  void consumeConstructionContext(const ConstructionContextLayer *Layer,
677  Expr *E);
678 
679  // Scan \p Child statement to find constructors in it, while keeping in mind
680  // that its parent statement is providing a partial construction context
681  // described by \p Layer. If a constructor is found, it would be assigned
682  // the context based on the layer. If an additional construction context layer
683  // is found, the function recurses into that.
684  void findConstructionContexts(const ConstructionContextLayer *Layer,
685  Stmt *Child);
686 
687  // Scan all arguments of a call expression for a construction context.
688  // These sorts of call expressions don't have a common superclass,
689  // hence strict duck-typing.
690  template <typename CallLikeExpr,
691  typename = typename std::enable_if<
692  std::is_same<CallLikeExpr, CallExpr>::value ||
693  std::is_same<CallLikeExpr, CXXConstructExpr>::value ||
694  std::is_same<CallLikeExpr, ObjCMessageExpr>::value>>
695  void findConstructionContextsForArguments(CallLikeExpr *E) {
696  for (unsigned i = 0, e = E->getNumArgs(); i != e; ++i) {
697  Expr *Arg = E->getArg(i);
698  if (Arg->getType()->getAsCXXRecordDecl() && !Arg->isGLValue())
699  findConstructionContexts(
700  ConstructionContextLayer::create(cfg->getBumpVectorContext(),
702  Arg);
703  }
704  }
705 
706  // Unset the construction context after consuming it. This is done immediately
707  // after adding the CFGConstructor or CFGCXXRecordTypedCall element, so
708  // there's no need to do this manually in every Visit... function.
709  void cleanupConstructionContext(Expr *E);
710 
711  void autoCreateBlock() { if (!Block) Block = createBlock(); }
712  CFGBlock *createBlock(bool add_successor = true);
713  CFGBlock *createNoReturnBlock();
714 
715  CFGBlock *addStmt(Stmt *S) {
716  return Visit(S, AddStmtChoice::AlwaysAdd);
717  }
718 
719  CFGBlock *addInitializer(CXXCtorInitializer *I);
720  void addLoopExit(const Stmt *LoopStmt);
721  void addAutomaticObjDtors(LocalScope::const_iterator B,
722  LocalScope::const_iterator E, Stmt *S);
723  void addLifetimeEnds(LocalScope::const_iterator B,
724  LocalScope::const_iterator E, Stmt *S);
725  void addAutomaticObjHandling(LocalScope::const_iterator B,
726  LocalScope::const_iterator E, Stmt *S);
727  void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD);
728  void addScopesEnd(LocalScope::const_iterator B, LocalScope::const_iterator E,
729  Stmt *S);
730 
731  void getDeclsWithEndedScope(LocalScope::const_iterator B,
732  LocalScope::const_iterator E, Stmt *S);
733 
734  // Local scopes creation.
735  LocalScope* createOrReuseLocalScope(LocalScope* Scope);
736 
737  void addLocalScopeForStmt(Stmt *S);
738  LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS,
739  LocalScope* Scope = nullptr);
740  LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = nullptr);
741 
742  void addLocalScopeAndDtors(Stmt *S);
743 
744  const ConstructionContext *retrieveAndCleanupConstructionContext(Expr *E) {
745  if (!BuildOpts.AddRichCXXConstructors)
746  return nullptr;
747 
748  const ConstructionContextLayer *Layer = ConstructionContextMap.lookup(E);
749  if (!Layer)
750  return nullptr;
751 
752  cleanupConstructionContext(E);
753  return ConstructionContext::createFromLayers(cfg->getBumpVectorContext(),
754  Layer);
755  }
756 
757  // Interface to CFGBlock - adding CFGElements.
758 
759  void appendStmt(CFGBlock *B, const Stmt *S) {
760  if (alwaysAdd(S) && cachedEntry)
761  cachedEntry->second = B;
762 
763  // All block-level expressions should have already been IgnoreParens()ed.
764  assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S);
765  B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext());
766  }
767 
768  void appendConstructor(CFGBlock *B, CXXConstructExpr *CE) {
769  if (const ConstructionContext *CC =
770  retrieveAndCleanupConstructionContext(CE)) {
771  B->appendConstructor(CE, CC, cfg->getBumpVectorContext());
772  return;
773  }
774 
775  // No valid construction context found. Fall back to statement.
776  B->appendStmt(CE, cfg->getBumpVectorContext());
777  }
778 
779  void appendCall(CFGBlock *B, CallExpr *CE) {
780  if (alwaysAdd(CE) && cachedEntry)
781  cachedEntry->second = B;
782 
783  if (const ConstructionContext *CC =
784  retrieveAndCleanupConstructionContext(CE)) {
785  B->appendCXXRecordTypedCall(CE, CC, cfg->getBumpVectorContext());
786  return;
787  }
788 
789  // No valid construction context found. Fall back to statement.
790  B->appendStmt(CE, cfg->getBumpVectorContext());
791  }
792 
793  void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) {
794  B->appendInitializer(I, cfg->getBumpVectorContext());
795  }
796 
797  void appendNewAllocator(CFGBlock *B, CXXNewExpr *NE) {
798  B->appendNewAllocator(NE, cfg->getBumpVectorContext());
799  }
800 
801  void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) {
802  B->appendBaseDtor(BS, cfg->getBumpVectorContext());
803  }
804 
805  void appendMemberDtor(CFGBlock *B, FieldDecl *FD) {
806  B->appendMemberDtor(FD, cfg->getBumpVectorContext());
807  }
808 
809  void appendObjCMessage(CFGBlock *B, ObjCMessageExpr *ME) {
810  if (alwaysAdd(ME) && cachedEntry)
811  cachedEntry->second = B;
812 
813  if (const ConstructionContext *CC =
814  retrieveAndCleanupConstructionContext(ME)) {
815  B->appendCXXRecordTypedCall(ME, CC, cfg->getBumpVectorContext());
816  return;
817  }
818 
819  B->appendStmt(const_cast<ObjCMessageExpr *>(ME),
820  cfg->getBumpVectorContext());
821  }
822 
823  void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) {
824  B->appendTemporaryDtor(E, cfg->getBumpVectorContext());
825  }
826 
827  void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) {
828  B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext());
829  }
830 
831  void appendLifetimeEnds(CFGBlock *B, VarDecl *VD, Stmt *S) {
832  B->appendLifetimeEnds(VD, S, cfg->getBumpVectorContext());
833  }
834 
835  void appendLoopExit(CFGBlock *B, const Stmt *LoopStmt) {
836  B->appendLoopExit(LoopStmt, cfg->getBumpVectorContext());
837  }
838 
839  void appendDeleteDtor(CFGBlock *B, CXXRecordDecl *RD, CXXDeleteExpr *DE) {
840  B->appendDeleteDtor(RD, DE, cfg->getBumpVectorContext());
841  }
842 
843  void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
844  LocalScope::const_iterator B, LocalScope::const_iterator E);
845 
846  void prependAutomaticObjLifetimeWithTerminator(CFGBlock *Blk,
847  LocalScope::const_iterator B,
848  LocalScope::const_iterator E);
849 
850  const VarDecl *
851  prependAutomaticObjScopeEndWithTerminator(CFGBlock *Blk,
852  LocalScope::const_iterator B,
853  LocalScope::const_iterator E);
854 
855  void addSuccessor(CFGBlock *B, CFGBlock *S, bool IsReachable = true) {
856  B->addSuccessor(CFGBlock::AdjacentBlock(S, IsReachable),
857  cfg->getBumpVectorContext());
858  }
859 
860  /// Add a reachable successor to a block, with the alternate variant that is
861  /// unreachable.
862  void addSuccessor(CFGBlock *B, CFGBlock *ReachableBlock, CFGBlock *AltBlock) {
863  B->addSuccessor(CFGBlock::AdjacentBlock(ReachableBlock, AltBlock),
864  cfg->getBumpVectorContext());
865  }
866 
867  void appendScopeBegin(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
868  if (BuildOpts.AddScopes)
869  B->appendScopeBegin(VD, S, cfg->getBumpVectorContext());
870  }
871 
872  void prependScopeBegin(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
873  if (BuildOpts.AddScopes)
874  B->prependScopeBegin(VD, S, cfg->getBumpVectorContext());
875  }
876 
877  void appendScopeEnd(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
878  if (BuildOpts.AddScopes)
879  B->appendScopeEnd(VD, S, cfg->getBumpVectorContext());
880  }
881 
882  void prependScopeEnd(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
883  if (BuildOpts.AddScopes)
884  B->prependScopeEnd(VD, S, cfg->getBumpVectorContext());
885  }
886 
887  /// Find a relational comparison with an expression evaluating to a
888  /// boolean and a constant other than 0 and 1.
889  /// e.g. if ((x < y) == 10)
890  TryResult checkIncorrectRelationalOperator(const BinaryOperator *B) {
891  const Expr *LHSExpr = B->getLHS()->IgnoreParens();
892  const Expr *RHSExpr = B->getRHS()->IgnoreParens();
893 
894  const IntegerLiteral *IntLiteral = dyn_cast<IntegerLiteral>(LHSExpr);
895  const Expr *BoolExpr = RHSExpr;
896  bool IntFirst = true;
897  if (!IntLiteral) {
898  IntLiteral = dyn_cast<IntegerLiteral>(RHSExpr);
899  BoolExpr = LHSExpr;
900  IntFirst = false;
901  }
902 
903  if (!IntLiteral || !BoolExpr->isKnownToHaveBooleanValue())
904  return TryResult();
905 
906  llvm::APInt IntValue = IntLiteral->getValue();
907  if ((IntValue == 1) || (IntValue == 0))
908  return TryResult();
909 
910  bool IntLarger = IntLiteral->getType()->isUnsignedIntegerType() ||
911  !IntValue.isNegative();
912 
913  BinaryOperatorKind Bok = B->getOpcode();
914  if (Bok == BO_GT || Bok == BO_GE) {
915  // Always true for 10 > bool and bool > -1
916  // Always false for -1 > bool and bool > 10
917  return TryResult(IntFirst == IntLarger);
918  } else {
919  // Always true for -1 < bool and bool < 10
920  // Always false for 10 < bool and bool < -1
921  return TryResult(IntFirst != IntLarger);
922  }
923  }
924 
925  /// Find an incorrect equality comparison. Either with an expression
926  /// evaluating to a boolean and a constant other than 0 and 1.
927  /// e.g. if (!x == 10) or a bitwise and/or operation that always evaluates to
928  /// true/false e.q. (x & 8) == 4.
929  TryResult checkIncorrectEqualityOperator(const BinaryOperator *B) {
930  const Expr *LHSExpr = B->getLHS()->IgnoreParens();
931  const Expr *RHSExpr = B->getRHS()->IgnoreParens();
932 
933  const IntegerLiteral *IntLiteral = dyn_cast<IntegerLiteral>(LHSExpr);
934  const Expr *BoolExpr = RHSExpr;
935 
936  if (!IntLiteral) {
937  IntLiteral = dyn_cast<IntegerLiteral>(RHSExpr);
938  BoolExpr = LHSExpr;
939  }
940 
941  if (!IntLiteral)
942  return TryResult();
943 
944  const BinaryOperator *BitOp = dyn_cast<BinaryOperator>(BoolExpr);
945  if (BitOp && (BitOp->getOpcode() == BO_And ||
946  BitOp->getOpcode() == BO_Or)) {
947  const Expr *LHSExpr2 = BitOp->getLHS()->IgnoreParens();
948  const Expr *RHSExpr2 = BitOp->getRHS()->IgnoreParens();
949 
950  const IntegerLiteral *IntLiteral2 = dyn_cast<IntegerLiteral>(LHSExpr2);
951 
952  if (!IntLiteral2)
953  IntLiteral2 = dyn_cast<IntegerLiteral>(RHSExpr2);
954 
955  if (!IntLiteral2)
956  return TryResult();
957 
958  llvm::APInt L1 = IntLiteral->getValue();
959  llvm::APInt L2 = IntLiteral2->getValue();
960  if ((BitOp->getOpcode() == BO_And && (L2 & L1) != L1) ||
961  (BitOp->getOpcode() == BO_Or && (L2 | L1) != L1)) {
962  if (BuildOpts.Observer)
963  BuildOpts.Observer->compareBitwiseEquality(B,
964  B->getOpcode() != BO_EQ);
965  TryResult(B->getOpcode() != BO_EQ);
966  }
967  } else if (BoolExpr->isKnownToHaveBooleanValue()) {
968  llvm::APInt IntValue = IntLiteral->getValue();
969  if ((IntValue == 1) || (IntValue == 0)) {
970  return TryResult();
971  }
972  return TryResult(B->getOpcode() != BO_EQ);
973  }
974 
975  return TryResult();
976  }
977 
978  TryResult analyzeLogicOperatorCondition(BinaryOperatorKind Relation,
979  const llvm::APSInt &Value1,
980  const llvm::APSInt &Value2) {
981  assert(Value1.isSigned() == Value2.isSigned());
982  switch (Relation) {
983  default:
984  return TryResult();
985  case BO_EQ:
986  return TryResult(Value1 == Value2);
987  case BO_NE:
988  return TryResult(Value1 != Value2);
989  case BO_LT:
990  return TryResult(Value1 < Value2);
991  case BO_LE:
992  return TryResult(Value1 <= Value2);
993  case BO_GT:
994  return TryResult(Value1 > Value2);
995  case BO_GE:
996  return TryResult(Value1 >= Value2);
997  }
998  }
999 
1000  /// Find a pair of comparison expressions with or without parentheses
1001  /// with a shared variable and constants and a logical operator between them
1002  /// that always evaluates to either true or false.
1003  /// e.g. if (x != 3 || x != 4)
1004  TryResult checkIncorrectLogicOperator(const BinaryOperator *B) {
1005  assert(B->isLogicalOp());
1006  const BinaryOperator *LHS =
1007  dyn_cast<BinaryOperator>(B->getLHS()->IgnoreParens());
1008  const BinaryOperator *RHS =
1009  dyn_cast<BinaryOperator>(B->getRHS()->IgnoreParens());
1010  if (!LHS || !RHS)
1011  return {};
1012 
1013  if (!LHS->isComparisonOp() || !RHS->isComparisonOp())
1014  return {};
1015 
1016  const DeclRefExpr *Decl1;
1017  const Expr *Expr1;
1018  BinaryOperatorKind BO1;
1019  std::tie(Decl1, BO1, Expr1) = tryNormalizeBinaryOperator(LHS);
1020 
1021  if (!Decl1 || !Expr1)
1022  return {};
1023 
1024  const DeclRefExpr *Decl2;
1025  const Expr *Expr2;
1026  BinaryOperatorKind BO2;
1027  std::tie(Decl2, BO2, Expr2) = tryNormalizeBinaryOperator(RHS);
1028 
1029  if (!Decl2 || !Expr2)
1030  return {};
1031 
1032  // Check that it is the same variable on both sides.
1033  if (Decl1->getDecl() != Decl2->getDecl())
1034  return {};
1035 
1036  // Make sure the user's intent is clear (e.g. they're comparing against two
1037  // int literals, or two things from the same enum)
1038  if (!areExprTypesCompatible(Expr1, Expr2))
1039  return {};
1040 
1041  Expr::EvalResult L1Result, L2Result;
1042  if (!Expr1->EvaluateAsInt(L1Result, *Context) ||
1043  !Expr2->EvaluateAsInt(L2Result, *Context))
1044  return {};
1045 
1046  llvm::APSInt L1 = L1Result.Val.getInt();
1047  llvm::APSInt L2 = L2Result.Val.getInt();
1048 
1049  // Can't compare signed with unsigned or with different bit width.
1050  if (L1.isSigned() != L2.isSigned() || L1.getBitWidth() != L2.getBitWidth())
1051  return {};
1052 
1053  // Values that will be used to determine if result of logical
1054  // operator is always true/false
1055  const llvm::APSInt Values[] = {
1056  // Value less than both Value1 and Value2
1057  llvm::APSInt::getMinValue(L1.getBitWidth(), L1.isUnsigned()),
1058  // L1
1059  L1,
1060  // Value between Value1 and Value2
1061  ((L1 < L2) ? L1 : L2) + llvm::APSInt(llvm::APInt(L1.getBitWidth(), 1),
1062  L1.isUnsigned()),
1063  // L2
1064  L2,
1065  // Value greater than both Value1 and Value2
1066  llvm::APSInt::getMaxValue(L1.getBitWidth(), L1.isUnsigned()),
1067  };
1068 
1069  // Check whether expression is always true/false by evaluating the following
1070  // * variable x is less than the smallest literal.
1071  // * variable x is equal to the smallest literal.
1072  // * Variable x is between smallest and largest literal.
1073  // * Variable x is equal to the largest literal.
1074  // * Variable x is greater than largest literal.
1075  bool AlwaysTrue = true, AlwaysFalse = true;
1076  for (const llvm::APSInt &Value : Values) {
1077  TryResult Res1, Res2;
1078  Res1 = analyzeLogicOperatorCondition(BO1, Value, L1);
1079  Res2 = analyzeLogicOperatorCondition(BO2, Value, L2);
1080 
1081  if (!Res1.isKnown() || !Res2.isKnown())
1082  return {};
1083 
1084  if (B->getOpcode() == BO_LAnd) {
1085  AlwaysTrue &= (Res1.isTrue() && Res2.isTrue());
1086  AlwaysFalse &= !(Res1.isTrue() && Res2.isTrue());
1087  } else {
1088  AlwaysTrue &= (Res1.isTrue() || Res2.isTrue());
1089  AlwaysFalse &= !(Res1.isTrue() || Res2.isTrue());
1090  }
1091  }
1092 
1093  if (AlwaysTrue || AlwaysFalse) {
1094  if (BuildOpts.Observer)
1095  BuildOpts.Observer->compareAlwaysTrue(B, AlwaysTrue);
1096  return TryResult(AlwaysTrue);
1097  }
1098  return {};
1099  }
1100 
1101  /// Try and evaluate an expression to an integer constant.
1102  bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) {
1103  if (!BuildOpts.PruneTriviallyFalseEdges)
1104  return false;
1105  return !S->isTypeDependent() &&
1106  !S->isValueDependent() &&
1107  S->EvaluateAsRValue(outResult, *Context);
1108  }
1109 
1110  /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1
1111  /// if we can evaluate to a known value, otherwise return -1.
1112  TryResult tryEvaluateBool(Expr *S) {
1113  if (!BuildOpts.PruneTriviallyFalseEdges ||
1114  S->isTypeDependent() || S->isValueDependent())
1115  return {};
1116 
1117  if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(S)) {
1118  if (Bop->isLogicalOp()) {
1119  // Check the cache first.
1120  CachedBoolEvalsTy::iterator I = CachedBoolEvals.find(S);
1121  if (I != CachedBoolEvals.end())
1122  return I->second; // already in map;
1123 
1124  // Retrieve result at first, or the map might be updated.
1125  TryResult Result = evaluateAsBooleanConditionNoCache(S);
1126  CachedBoolEvals[S] = Result; // update or insert
1127  return Result;
1128  }
1129  else {
1130  switch (Bop->getOpcode()) {
1131  default: break;
1132  // For 'x & 0' and 'x * 0', we can determine that
1133  // the value is always false.
1134  case BO_Mul:
1135  case BO_And: {
1136  // If either operand is zero, we know the value
1137  // must be false.
1138  Expr::EvalResult LHSResult;
1139  if (Bop->getLHS()->EvaluateAsInt(LHSResult, *Context)) {
1140  llvm::APSInt IntVal = LHSResult.Val.getInt();
1141  if (!IntVal.getBoolValue()) {
1142  return TryResult(false);
1143  }
1144  }
1145  Expr::EvalResult RHSResult;
1146  if (Bop->getRHS()->EvaluateAsInt(RHSResult, *Context)) {
1147  llvm::APSInt IntVal = RHSResult.Val.getInt();
1148  if (!IntVal.getBoolValue()) {
1149  return TryResult(false);
1150  }
1151  }
1152  }
1153  break;
1154  }
1155  }
1156  }
1157 
1158  return evaluateAsBooleanConditionNoCache(S);
1159  }
1160 
1161  /// Evaluate as boolean \param E without using the cache.
1162  TryResult evaluateAsBooleanConditionNoCache(Expr *E) {
1163  if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(E)) {
1164  if (Bop->isLogicalOp()) {
1165  TryResult LHS = tryEvaluateBool(Bop->getLHS());
1166  if (LHS.isKnown()) {
1167  // We were able to evaluate the LHS, see if we can get away with not
1168  // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
1169  if (LHS.isTrue() == (Bop->getOpcode() == BO_LOr))
1170  return LHS.isTrue();
1171 
1172  TryResult RHS = tryEvaluateBool(Bop->getRHS());
1173  if (RHS.isKnown()) {
1174  if (Bop->getOpcode() == BO_LOr)
1175  return LHS.isTrue() || RHS.isTrue();
1176  else
1177  return LHS.isTrue() && RHS.isTrue();
1178  }
1179  } else {
1180  TryResult RHS = tryEvaluateBool(Bop->getRHS());
1181  if (RHS.isKnown()) {
1182  // We can't evaluate the LHS; however, sometimes the result
1183  // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
1184  if (RHS.isTrue() == (Bop->getOpcode() == BO_LOr))
1185  return RHS.isTrue();
1186  } else {
1187  TryResult BopRes = checkIncorrectLogicOperator(Bop);
1188  if (BopRes.isKnown())
1189  return BopRes.isTrue();
1190  }
1191  }
1192 
1193  return {};
1194  } else if (Bop->isEqualityOp()) {
1195  TryResult BopRes = checkIncorrectEqualityOperator(Bop);
1196  if (BopRes.isKnown())
1197  return BopRes.isTrue();
1198  } else if (Bop->isRelationalOp()) {
1199  TryResult BopRes = checkIncorrectRelationalOperator(Bop);
1200  if (BopRes.isKnown())
1201  return BopRes.isTrue();
1202  }
1203  }
1204 
1205  bool Result;
1206  if (E->EvaluateAsBooleanCondition(Result, *Context))
1207  return Result;
1208 
1209  return {};
1210  }
1211 
1212  bool hasTrivialDestructor(VarDecl *VD);
1213 };
1214 
1215 } // namespace
1216 
1217 inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder,
1218  const Stmt *stmt) const {
1219  return builder.alwaysAdd(stmt) || kind == AlwaysAdd;
1220 }
1221 
1222 bool CFGBuilder::alwaysAdd(const Stmt *stmt) {
1223  bool shouldAdd = BuildOpts.alwaysAdd(stmt);
1224 
1225  if (!BuildOpts.forcedBlkExprs)
1226  return shouldAdd;
1227 
1228  if (lastLookup == stmt) {
1229  if (cachedEntry) {
1230  assert(cachedEntry->first == stmt);
1231  return true;
1232  }
1233  return shouldAdd;
1234  }
1235 
1236  lastLookup = stmt;
1237 
1238  // Perform the lookup!
1239  CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs;
1240 
1241  if (!fb) {
1242  // No need to update 'cachedEntry', since it will always be null.
1243  assert(!cachedEntry);
1244  return shouldAdd;
1245  }
1246 
1247  CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt);
1248  if (itr == fb->end()) {
1249  cachedEntry = nullptr;
1250  return shouldAdd;
1251  }
1252 
1253  cachedEntry = &*itr;
1254  return true;
1255 }
1256 
1257 // FIXME: Add support for dependent-sized array types in C++?
1258 // Does it even make sense to build a CFG for an uninstantiated template?
1259 static const VariableArrayType *FindVA(const Type *t) {
1260  while (const ArrayType *vt = dyn_cast<ArrayType>(t)) {
1261  if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt))
1262  if (vat->getSizeExpr())
1263  return vat;
1264 
1265  t = vt->getElementType().getTypePtr();
1266  }
1267 
1268  return nullptr;
1269 }
1270 
1271 void CFGBuilder::consumeConstructionContext(
1272  const ConstructionContextLayer *Layer, Expr *E) {
1273  assert((isa<CXXConstructExpr>(E) || isa<CallExpr>(E) ||
1274  isa<ObjCMessageExpr>(E)) && "Expression cannot construct an object!");
1275  if (const ConstructionContextLayer *PreviouslyStoredLayer =
1276  ConstructionContextMap.lookup(E)) {
1277  (void)PreviouslyStoredLayer;
1278  // We might have visited this child when we were finding construction
1279  // contexts within its parents.
1280  assert(PreviouslyStoredLayer->isStrictlyMoreSpecificThan(Layer) &&
1281  "Already within a different construction context!");
1282  } else {
1283  ConstructionContextMap[E] = Layer;
1284  }
1285 }
1286 
1287 void CFGBuilder::findConstructionContexts(
1288  const ConstructionContextLayer *Layer, Stmt *Child) {
1289  if (!BuildOpts.AddRichCXXConstructors)
1290  return;
1291 
1292  if (!Child)
1293  return;
1294 
1295  auto withExtraLayer = [this, Layer](const ConstructionContextItem &Item) {
1296  return ConstructionContextLayer::create(cfg->getBumpVectorContext(), Item,
1297  Layer);
1298  };
1299 
1300  switch(Child->getStmtClass()) {
1301  case Stmt::CXXConstructExprClass:
1302  case Stmt::CXXTemporaryObjectExprClass: {
1303  // Support pre-C++17 copy elision AST.
1304  auto *CE = cast<CXXConstructExpr>(Child);
1305  if (BuildOpts.MarkElidedCXXConstructors && CE->isElidable()) {
1306  findConstructionContexts(withExtraLayer(CE), CE->getArg(0));
1307  }
1308 
1309  consumeConstructionContext(Layer, CE);
1310  break;
1311  }
1312  // FIXME: This, like the main visit, doesn't support CUDAKernelCallExpr.
1313  // FIXME: An isa<> would look much better but this whole switch is a
1314  // workaround for an internal compiler error in MSVC 2015 (see r326021).
1315  case Stmt::CallExprClass:
1316  case Stmt::CXXMemberCallExprClass:
1317  case Stmt::CXXOperatorCallExprClass:
1318  case Stmt::UserDefinedLiteralClass:
1319  case Stmt::ObjCMessageExprClass: {
1320  auto *E = cast<Expr>(Child);
1322  consumeConstructionContext(Layer, E);
1323  break;
1324  }
1325  case Stmt::ExprWithCleanupsClass: {
1326  auto *Cleanups = cast<ExprWithCleanups>(Child);
1327  findConstructionContexts(Layer, Cleanups->getSubExpr());
1328  break;
1329  }
1330  case Stmt::CXXFunctionalCastExprClass: {
1331  auto *Cast = cast<CXXFunctionalCastExpr>(Child);
1332  findConstructionContexts(Layer, Cast->getSubExpr());
1333  break;
1334  }
1335  case Stmt::ImplicitCastExprClass: {
1336  auto *Cast = cast<ImplicitCastExpr>(Child);
1337  // Should we support other implicit cast kinds?
1338  switch (Cast->getCastKind()) {
1339  case CK_NoOp:
1340  case CK_ConstructorConversion:
1341  findConstructionContexts(Layer, Cast->getSubExpr());
1342  break;
1343  default:
1344  break;
1345  }
1346  break;
1347  }
1348  case Stmt::CXXBindTemporaryExprClass: {
1349  auto *BTE = cast<CXXBindTemporaryExpr>(Child);
1350  findConstructionContexts(withExtraLayer(BTE), BTE->getSubExpr());
1351  break;
1352  }
1353  case Stmt::MaterializeTemporaryExprClass: {
1354  // Normally we don't want to search in MaterializeTemporaryExpr because
1355  // it indicates the beginning of a temporary object construction context,
1356  // so it shouldn't be found in the middle. However, if it is the beginning
1357  // of an elidable copy or move construction context, we need to include it.
1358  if (Layer->getItem().getKind() ==
1360  auto *MTE = cast<MaterializeTemporaryExpr>(Child);
1361  findConstructionContexts(withExtraLayer(MTE), MTE->GetTemporaryExpr());
1362  }
1363  break;
1364  }
1365  case Stmt::ConditionalOperatorClass: {
1366  auto *CO = cast<ConditionalOperator>(Child);
1367  if (Layer->getItem().getKind() !=
1369  // If the object returned by the conditional operator is not going to be a
1370  // temporary object that needs to be immediately materialized, then
1371  // it must be C++17 with its mandatory copy elision. Do not yet promise
1372  // to support this case.
1373  assert(!CO->getType()->getAsCXXRecordDecl() || CO->isGLValue() ||
1374  Context->getLangOpts().CPlusPlus17);
1375  break;
1376  }
1377  findConstructionContexts(Layer, CO->getLHS());
1378  findConstructionContexts(Layer, CO->getRHS());
1379  break;
1380  }
1381  case Stmt::InitListExprClass: {
1382  auto *ILE = cast<InitListExpr>(Child);
1383  if (ILE->isTransparent()) {
1384  findConstructionContexts(Layer, ILE->getInit(0));
1385  break;
1386  }
1387  // TODO: Handle other cases. For now, fail to find construction contexts.
1388  break;
1389  }
1390  default:
1391  break;
1392  }
1393 }
1394 
1395 void CFGBuilder::cleanupConstructionContext(Expr *E) {
1396  assert(BuildOpts.AddRichCXXConstructors &&
1397  "We should not be managing construction contexts!");
1398  assert(ConstructionContextMap.count(E) &&
1399  "Cannot exit construction context without the context!");
1400  ConstructionContextMap.erase(E);
1401 }
1402 
1403 
1404 /// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an
1405 /// arbitrary statement. Examples include a single expression or a function
1406 /// body (compound statement). The ownership of the returned CFG is
1407 /// transferred to the caller. If CFG construction fails, this method returns
1408 /// NULL.
1409 std::unique_ptr<CFG> CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) {
1410  assert(cfg.get());
1411  if (!Statement)
1412  return nullptr;
1413 
1414  // Create an empty block that will serve as the exit block for the CFG. Since
1415  // this is the first block added to the CFG, it will be implicitly registered
1416  // as the exit block.
1417  Succ = createBlock();
1418  assert(Succ == &cfg->getExit());
1419  Block = nullptr; // the EXIT block is empty. Create all other blocks lazily.
1420 
1421  assert(!(BuildOpts.AddImplicitDtors && BuildOpts.AddLifetime) &&
1422  "AddImplicitDtors and AddLifetime cannot be used at the same time");
1423 
1424  if (BuildOpts.AddImplicitDtors)
1425  if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D))
1426  addImplicitDtorsForDestructor(DD);
1427 
1428  // Visit the statements and create the CFG.
1429  CFGBlock *B = addStmt(Statement);
1430 
1431  if (badCFG)
1432  return nullptr;
1433 
1434  // For C++ constructor add initializers to CFG.
1435  if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) {
1436  for (auto *I : llvm::reverse(CD->inits())) {
1437  B = addInitializer(I);
1438  if (badCFG)
1439  return nullptr;
1440  }
1441  }
1442 
1443  if (B)
1444  Succ = B;
1445 
1446  // Backpatch the gotos whose label -> block mappings we didn't know when we
1447  // encountered them.
1448  for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(),
1449  E = BackpatchBlocks.end(); I != E; ++I ) {
1450 
1451  CFGBlock *B = I->block;
1452  const GotoStmt *G = cast<GotoStmt>(B->getTerminator());
1453  LabelMapTy::iterator LI = LabelMap.find(G->getLabel());
1454 
1455  // If there is no target for the goto, then we are looking at an
1456  // incomplete AST. Handle this by not registering a successor.
1457  if (LI == LabelMap.end()) continue;
1458 
1459  JumpTarget JT = LI->second;
1460  prependAutomaticObjLifetimeWithTerminator(B, I->scopePosition,
1461  JT.scopePosition);
1462  prependAutomaticObjDtorsWithTerminator(B, I->scopePosition,
1463  JT.scopePosition);
1464  const VarDecl *VD = prependAutomaticObjScopeEndWithTerminator(
1465  B, I->scopePosition, JT.scopePosition);
1466  appendScopeBegin(JT.block, VD, G);
1467  addSuccessor(B, JT.block);
1468  }
1469 
1470  // Add successors to the Indirect Goto Dispatch block (if we have one).
1471  if (CFGBlock *B = cfg->getIndirectGotoBlock())
1472  for (LabelSetTy::iterator I = AddressTakenLabels.begin(),
1473  E = AddressTakenLabels.end(); I != E; ++I ) {
1474  // Lookup the target block.
1475  LabelMapTy::iterator LI = LabelMap.find(*I);
1476 
1477  // If there is no target block that contains label, then we are looking
1478  // at an incomplete AST. Handle this by not registering a successor.
1479  if (LI == LabelMap.end()) continue;
1480 
1481  addSuccessor(B, LI->second.block);
1482  }
1483 
1484  // Create an empty entry block that has no predecessors.
1485  cfg->setEntry(createBlock());
1486 
1487  if (BuildOpts.AddRichCXXConstructors)
1488  assert(ConstructionContextMap.empty() &&
1489  "Not all construction contexts were cleaned up!");
1490 
1491  return std::move(cfg);
1492 }
1493 
1494 /// createBlock - Used to lazily create blocks that are connected
1495 /// to the current (global) succcessor.
1496 CFGBlock *CFGBuilder::createBlock(bool add_successor) {
1497  CFGBlock *B = cfg->createBlock();
1498  if (add_successor && Succ)
1499  addSuccessor(B, Succ);
1500  return B;
1501 }
1502 
1503 /// createNoReturnBlock - Used to create a block is a 'noreturn' point in the
1504 /// CFG. It is *not* connected to the current (global) successor, and instead
1505 /// directly tied to the exit block in order to be reachable.
1506 CFGBlock *CFGBuilder::createNoReturnBlock() {
1507  CFGBlock *B = createBlock(false);
1508  B->setHasNoReturnElement();
1509  addSuccessor(B, &cfg->getExit(), Succ);
1510  return B;
1511 }
1512 
1513 /// addInitializer - Add C++ base or member initializer element to CFG.
1514 CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) {
1515  if (!BuildOpts.AddInitializers)
1516  return Block;
1517 
1518  bool HasTemporaries = false;
1519 
1520  // Destructors of temporaries in initialization expression should be called
1521  // after initialization finishes.
1522  Expr *Init = I->getInit();
1523  if (Init) {
1524  HasTemporaries = isa<ExprWithCleanups>(Init);
1525 
1526  if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
1527  // Generate destructors for temporaries in initialization expression.
1528  TempDtorContext Context;
1529  VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
1530  /*BindToTemporary=*/false, Context);
1531  }
1532  }
1533 
1534  autoCreateBlock();
1535  appendInitializer(Block, I);
1536 
1537  if (Init) {
1538  findConstructionContexts(
1539  ConstructionContextLayer::create(cfg->getBumpVectorContext(), I),
1540  Init);
1541 
1542  if (HasTemporaries) {
1543  // For expression with temporaries go directly to subexpression to omit
1544  // generating destructors for the second time.
1545  return Visit(cast<ExprWithCleanups>(Init)->getSubExpr());
1546  }
1547  if (BuildOpts.AddCXXDefaultInitExprInCtors) {
1548  if (CXXDefaultInitExpr *Default = dyn_cast<CXXDefaultInitExpr>(Init)) {
1549  // In general, appending the expression wrapped by a CXXDefaultInitExpr
1550  // may cause the same Expr to appear more than once in the CFG. Doing it
1551  // here is safe because there's only one initializer per field.
1552  autoCreateBlock();
1553  appendStmt(Block, Default);
1554  if (Stmt *Child = Default->getExpr())
1555  if (CFGBlock *R = Visit(Child))
1556  Block = R;
1557  return Block;
1558  }
1559  }
1560  return Visit(Init);
1561  }
1562 
1563  return Block;
1564 }
1565 
1566 /// Retrieve the type of the temporary object whose lifetime was
1567 /// extended by a local reference with the given initializer.
1569  bool *FoundMTE = nullptr) {
1570  while (true) {
1571  // Skip parentheses.
1572  Init = Init->IgnoreParens();
1573 
1574  // Skip through cleanups.
1575  if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Init)) {
1576  Init = EWC->getSubExpr();
1577  continue;
1578  }
1579 
1580  // Skip through the temporary-materialization expression.
1581  if (const MaterializeTemporaryExpr *MTE
1582  = dyn_cast<MaterializeTemporaryExpr>(Init)) {
1583  Init = MTE->GetTemporaryExpr();
1584  if (FoundMTE)
1585  *FoundMTE = true;
1586  continue;
1587  }
1588 
1589  // Skip sub-object accesses into rvalues.
1590  SmallVector<const Expr *, 2> CommaLHSs;
1592  const Expr *SkippedInit =
1593  Init->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
1594  if (SkippedInit != Init) {
1595  Init = SkippedInit;
1596  continue;
1597  }
1598 
1599  break;
1600  }
1601 
1602  return Init->getType();
1603 }
1604 
1605 // TODO: Support adding LoopExit element to the CFG in case where the loop is
1606 // ended by ReturnStmt, GotoStmt or ThrowExpr.
1607 void CFGBuilder::addLoopExit(const Stmt *LoopStmt){
1608  if(!BuildOpts.AddLoopExit)
1609  return;
1610  autoCreateBlock();
1611  appendLoopExit(Block, LoopStmt);
1612 }
1613 
1614 void CFGBuilder::getDeclsWithEndedScope(LocalScope::const_iterator B,
1615  LocalScope::const_iterator E, Stmt *S) {
1616  if (!BuildOpts.AddScopes)
1617  return;
1618 
1619  if (B == E)
1620  return;
1621 
1622  // To go from B to E, one first goes up the scopes from B to P
1623  // then sideways in one scope from P to P' and then down
1624  // the scopes from P' to E.
1625  // The lifetime of all objects between B and P end.
1626  LocalScope::const_iterator P = B.shared_parent(E);
1627  int Dist = B.distance(P);
1628  if (Dist <= 0)
1629  return;
1630 
1631  for (LocalScope::const_iterator I = B; I != P; ++I)
1632  if (I.pointsToFirstDeclaredVar())
1633  DeclsWithEndedScope.insert(*I);
1634 }
1635 
1636 void CFGBuilder::addAutomaticObjHandling(LocalScope::const_iterator B,
1637  LocalScope::const_iterator E,
1638  Stmt *S) {
1639  getDeclsWithEndedScope(B, E, S);
1640  if (BuildOpts.AddScopes)
1641  addScopesEnd(B, E, S);
1642  if (BuildOpts.AddImplicitDtors)
1643  addAutomaticObjDtors(B, E, S);
1644  if (BuildOpts.AddLifetime)
1645  addLifetimeEnds(B, E, S);
1646 }
1647 
1648 /// Add to current block automatic objects that leave the scope.
1649 void CFGBuilder::addLifetimeEnds(LocalScope::const_iterator B,
1650  LocalScope::const_iterator E, Stmt *S) {
1651  if (!BuildOpts.AddLifetime)
1652  return;
1653 
1654  if (B == E)
1655  return;
1656 
1657  // To go from B to E, one first goes up the scopes from B to P
1658  // then sideways in one scope from P to P' and then down
1659  // the scopes from P' to E.
1660  // The lifetime of all objects between B and P end.
1661  LocalScope::const_iterator P = B.shared_parent(E);
1662  int dist = B.distance(P);
1663  if (dist <= 0)
1664  return;
1665 
1666  // We need to perform the scope leaving in reverse order
1667  SmallVector<VarDecl *, 10> DeclsTrivial;
1668  SmallVector<VarDecl *, 10> DeclsNonTrivial;
1669  DeclsTrivial.reserve(dist);
1670  DeclsNonTrivial.reserve(dist);
1671 
1672  for (LocalScope::const_iterator I = B; I != P; ++I)
1673  if (hasTrivialDestructor(*I))
1674  DeclsTrivial.push_back(*I);
1675  else
1676  DeclsNonTrivial.push_back(*I);
1677 
1678  autoCreateBlock();
1679  // object with trivial destructor end their lifetime last (when storage
1680  // duration ends)
1681  for (SmallVectorImpl<VarDecl *>::reverse_iterator I = DeclsTrivial.rbegin(),
1682  E = DeclsTrivial.rend();
1683  I != E; ++I)
1684  appendLifetimeEnds(Block, *I, S);
1685 
1687  I = DeclsNonTrivial.rbegin(),
1688  E = DeclsNonTrivial.rend();
1689  I != E; ++I)
1690  appendLifetimeEnds(Block, *I, S);
1691 }
1692 
1693 /// Add to current block markers for ending scopes.
1694 void CFGBuilder::addScopesEnd(LocalScope::const_iterator B,
1695  LocalScope::const_iterator E, Stmt *S) {
1696  // If implicit destructors are enabled, we'll add scope ends in
1697  // addAutomaticObjDtors.
1698  if (BuildOpts.AddImplicitDtors)
1699  return;
1700 
1701  autoCreateBlock();
1702 
1703  for (auto I = DeclsWithEndedScope.rbegin(), E = DeclsWithEndedScope.rend();
1704  I != E; ++I)
1705  appendScopeEnd(Block, *I, S);
1706 
1707  return;
1708 }
1709 
1710 /// addAutomaticObjDtors - Add to current block automatic objects destructors
1711 /// for objects in range of local scope positions. Use S as trigger statement
1712 /// for destructors.
1713 void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B,
1714  LocalScope::const_iterator E, Stmt *S) {
1715  if (!BuildOpts.AddImplicitDtors)
1716  return;
1717 
1718  if (B == E)
1719  return;
1720 
1721  // We need to append the destructors in reverse order, but any one of them
1722  // may be a no-return destructor which changes the CFG. As a result, buffer
1723  // this sequence up and replay them in reverse order when appending onto the
1724  // CFGBlock(s).
1726  Decls.reserve(B.distance(E));
1727  for (LocalScope::const_iterator I = B; I != E; ++I)
1728  Decls.push_back(*I);
1729 
1730  for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(),
1731  E = Decls.rend();
1732  I != E; ++I) {
1733  if (hasTrivialDestructor(*I)) {
1734  // If AddScopes is enabled and *I is a first variable in a scope, add a
1735  // ScopeEnd marker in a Block.
1736  if (BuildOpts.AddScopes && DeclsWithEndedScope.count(*I)) {
1737  autoCreateBlock();
1738  appendScopeEnd(Block, *I, S);
1739  }
1740  continue;
1741  }
1742  // If this destructor is marked as a no-return destructor, we need to
1743  // create a new block for the destructor which does not have as a successor
1744  // anything built thus far: control won't flow out of this block.
1745  QualType Ty = (*I)->getType();
1746  if (Ty->isReferenceType()) {
1747  Ty = getReferenceInitTemporaryType((*I)->getInit());
1748  }
1749  Ty = Context->getBaseElementType(Ty);
1750 
1751  if (Ty->getAsCXXRecordDecl()->isAnyDestructorNoReturn())
1752  Block = createNoReturnBlock();
1753  else
1754  autoCreateBlock();
1755 
1756  // Add ScopeEnd just after automatic obj destructor.
1757  if (BuildOpts.AddScopes && DeclsWithEndedScope.count(*I))
1758  appendScopeEnd(Block, *I, S);
1759  appendAutomaticObjDtor(Block, *I, S);
1760  }
1761 }
1762 
1763 /// addImplicitDtorsForDestructor - Add implicit destructors generated for
1764 /// base and member objects in destructor.
1765 void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) {
1766  assert(BuildOpts.AddImplicitDtors &&
1767  "Can be called only when dtors should be added");
1768  const CXXRecordDecl *RD = DD->getParent();
1769 
1770  // At the end destroy virtual base objects.
1771  for (const auto &VI : RD->vbases()) {
1772  const CXXRecordDecl *CD = VI.getType()->getAsCXXRecordDecl();
1773  if (!CD->hasTrivialDestructor()) {
1774  autoCreateBlock();
1775  appendBaseDtor(Block, &VI);
1776  }
1777  }
1778 
1779  // Before virtual bases destroy direct base objects.
1780  for (const auto &BI : RD->bases()) {
1781  if (!BI.isVirtual()) {
1782  const CXXRecordDecl *CD = BI.getType()->getAsCXXRecordDecl();
1783  if (!CD->hasTrivialDestructor()) {
1784  autoCreateBlock();
1785  appendBaseDtor(Block, &BI);
1786  }
1787  }
1788  }
1789 
1790  // First destroy member objects.
1791  for (auto *FI : RD->fields()) {
1792  // Check for constant size array. Set type to array element type.
1793  QualType QT = FI->getType();
1794  if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
1795  if (AT->getSize() == 0)
1796  continue;
1797  QT = AT->getElementType();
1798  }
1799 
1800  if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
1801  if (!CD->hasTrivialDestructor()) {
1802  autoCreateBlock();
1803  appendMemberDtor(Block, FI);
1804  }
1805  }
1806 }
1807 
1808 /// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either
1809 /// way return valid LocalScope object.
1810 LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) {
1811  if (Scope)
1812  return Scope;
1813  llvm::BumpPtrAllocator &alloc = cfg->getAllocator();
1814  return new (alloc.Allocate<LocalScope>())
1815  LocalScope(BumpVectorContext(alloc), ScopePos);
1816 }
1817 
1818 /// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement
1819 /// that should create implicit scope (e.g. if/else substatements).
1820 void CFGBuilder::addLocalScopeForStmt(Stmt *S) {
1821  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1822  !BuildOpts.AddScopes)
1823  return;
1824 
1825  LocalScope *Scope = nullptr;
1826 
1827  // For compound statement we will be creating explicit scope.
1828  if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
1829  for (auto *BI : CS->body()) {
1830  Stmt *SI = BI->stripLabelLikeStatements();
1831  if (DeclStmt *DS = dyn_cast<DeclStmt>(SI))
1832  Scope = addLocalScopeForDeclStmt(DS, Scope);
1833  }
1834  return;
1835  }
1836 
1837  // For any other statement scope will be implicit and as such will be
1838  // interesting only for DeclStmt.
1839  if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements()))
1840  addLocalScopeForDeclStmt(DS);
1841 }
1842 
1843 /// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will
1844 /// reuse Scope if not NULL.
1845 LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS,
1846  LocalScope* Scope) {
1847  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1848  !BuildOpts.AddScopes)
1849  return Scope;
1850 
1851  for (auto *DI : DS->decls())
1852  if (VarDecl *VD = dyn_cast<VarDecl>(DI))
1853  Scope = addLocalScopeForVarDecl(VD, Scope);
1854  return Scope;
1855 }
1856 
1857 bool CFGBuilder::hasTrivialDestructor(VarDecl *VD) {
1858  // Check for const references bound to temporary. Set type to pointee.
1859  QualType QT = VD->getType();
1860  if (QT->isReferenceType()) {
1861  // Attempt to determine whether this declaration lifetime-extends a
1862  // temporary.
1863  //
1864  // FIXME: This is incorrect. Non-reference declarations can lifetime-extend
1865  // temporaries, and a single declaration can extend multiple temporaries.
1866  // We should look at the storage duration on each nested
1867  // MaterializeTemporaryExpr instead.
1868 
1869  const Expr *Init = VD->getInit();
1870  if (!Init) {
1871  // Probably an exception catch-by-reference variable.
1872  // FIXME: It doesn't really mean that the object has a trivial destructor.
1873  // Also are there other cases?
1874  return true;
1875  }
1876 
1877  // Lifetime-extending a temporary?
1878  bool FoundMTE = false;
1879  QT = getReferenceInitTemporaryType(Init, &FoundMTE);
1880  if (!FoundMTE)
1881  return true;
1882  }
1883 
1884  // Check for constant size array. Set type to array element type.
1885  while (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
1886  if (AT->getSize() == 0)
1887  return true;
1888  QT = AT->getElementType();
1889  }
1890 
1891  // Check if type is a C++ class with non-trivial destructor.
1892  if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
1893  return !CD->hasDefinition() || CD->hasTrivialDestructor();
1894  return true;
1895 }
1896 
1897 /// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will
1898 /// create add scope for automatic objects and temporary objects bound to
1899 /// const reference. Will reuse Scope if not NULL.
1900 LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD,
1901  LocalScope* Scope) {
1902  assert(!(BuildOpts.AddImplicitDtors && BuildOpts.AddLifetime) &&
1903  "AddImplicitDtors and AddLifetime cannot be used at the same time");
1904  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1905  !BuildOpts.AddScopes)
1906  return Scope;
1907 
1908  // Check if variable is local.
1909  switch (VD->getStorageClass()) {
1910  case SC_None:
1911  case SC_Auto:
1912  case SC_Register:
1913  break;
1914  default: return Scope;
1915  }
1916 
1917  if (BuildOpts.AddImplicitDtors) {
1918  if (!hasTrivialDestructor(VD) || BuildOpts.AddScopes) {
1919  // Add the variable to scope
1920  Scope = createOrReuseLocalScope(Scope);
1921  Scope->addVar(VD);
1922  ScopePos = Scope->begin();
1923  }
1924  return Scope;
1925  }
1926 
1927  assert(BuildOpts.AddLifetime);
1928  // Add the variable to scope
1929  Scope = createOrReuseLocalScope(Scope);
1930  Scope->addVar(VD);
1931  ScopePos = Scope->begin();
1932  return Scope;
1933 }
1934 
1935 /// addLocalScopeAndDtors - For given statement add local scope for it and
1936 /// add destructors that will cleanup the scope. Will reuse Scope if not NULL.
1937 void CFGBuilder::addLocalScopeAndDtors(Stmt *S) {
1938  LocalScope::const_iterator scopeBeginPos = ScopePos;
1939  addLocalScopeForStmt(S);
1940  addAutomaticObjHandling(ScopePos, scopeBeginPos, S);
1941 }
1942 
1943 /// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for
1944 /// variables with automatic storage duration to CFGBlock's elements vector.
1945 /// Elements will be prepended to physical beginning of the vector which
1946 /// happens to be logical end. Use blocks terminator as statement that specifies
1947 /// destructors call site.
1948 /// FIXME: This mechanism for adding automatic destructors doesn't handle
1949 /// no-return destructors properly.
1950 void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
1951  LocalScope::const_iterator B, LocalScope::const_iterator E) {
1952  if (!BuildOpts.AddImplicitDtors)
1953  return;
1954  BumpVectorContext &C = cfg->getBumpVectorContext();
1955  CFGBlock::iterator InsertPos
1956  = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C);
1957  for (LocalScope::const_iterator I = B; I != E; ++I)
1958  InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I,
1959  Blk->getTerminator());
1960 }
1961 
1962 /// prependAutomaticObjLifetimeWithTerminator - Prepend lifetime CFGElements for
1963 /// variables with automatic storage duration to CFGBlock's elements vector.
1964 /// Elements will be prepended to physical beginning of the vector which
1965 /// happens to be logical end. Use blocks terminator as statement that specifies
1966 /// where lifetime ends.
1967 void CFGBuilder::prependAutomaticObjLifetimeWithTerminator(
1968  CFGBlock *Blk, LocalScope::const_iterator B, LocalScope::const_iterator E) {
1969  if (!BuildOpts.AddLifetime)
1970  return;
1971  BumpVectorContext &C = cfg->getBumpVectorContext();
1972  CFGBlock::iterator InsertPos =
1973  Blk->beginLifetimeEndsInsert(Blk->end(), B.distance(E), C);
1974  for (LocalScope::const_iterator I = B; I != E; ++I)
1975  InsertPos = Blk->insertLifetimeEnds(InsertPos, *I, Blk->getTerminator());
1976 }
1977 
1978 /// prependAutomaticObjScopeEndWithTerminator - Prepend scope end CFGElements for
1979 /// variables with automatic storage duration to CFGBlock's elements vector.
1980 /// Elements will be prepended to physical beginning of the vector which
1981 /// happens to be logical end. Use blocks terminator as statement that specifies
1982 /// where scope ends.
1983 const VarDecl *
1984 CFGBuilder::prependAutomaticObjScopeEndWithTerminator(
1985  CFGBlock *Blk, LocalScope::const_iterator B, LocalScope::const_iterator E) {
1986  if (!BuildOpts.AddScopes)
1987  return nullptr;
1988  BumpVectorContext &C = cfg->getBumpVectorContext();
1989  CFGBlock::iterator InsertPos =
1990  Blk->beginScopeEndInsert(Blk->end(), 1, C);
1991  LocalScope::const_iterator PlaceToInsert = B;
1992  for (LocalScope::const_iterator I = B; I != E; ++I)
1993  PlaceToInsert = I;
1994  Blk->insertScopeEnd(InsertPos, *PlaceToInsert, Blk->getTerminator());
1995  return *PlaceToInsert;
1996 }
1997 
1998 /// Visit - Walk the subtree of a statement and add extra
1999 /// blocks for ternary operators, &&, and ||. We also process "," and
2000 /// DeclStmts (which may contain nested control-flow).
2001 CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) {
2002  if (!S) {
2003  badCFG = true;
2004  return nullptr;
2005  }
2006 
2007  if (Expr *E = dyn_cast<Expr>(S))
2008  S = E->IgnoreParens();
2009 
2010  switch (S->getStmtClass()) {
2011  default:
2012  return VisitStmt(S, asc);
2013 
2014  case Stmt::AddrLabelExprClass:
2015  return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc);
2016 
2017  case Stmt::BinaryConditionalOperatorClass:
2018  return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc);
2019 
2020  case Stmt::BinaryOperatorClass:
2021  return VisitBinaryOperator(cast<BinaryOperator>(S), asc);
2022 
2023  case Stmt::BlockExprClass:
2024  return VisitBlockExpr(cast<BlockExpr>(S), asc);
2025 
2026  case Stmt::BreakStmtClass:
2027  return VisitBreakStmt(cast<BreakStmt>(S));
2028 
2029  case Stmt::CallExprClass:
2030  case Stmt::CXXOperatorCallExprClass:
2031  case Stmt::CXXMemberCallExprClass:
2032  case Stmt::UserDefinedLiteralClass:
2033  return VisitCallExpr(cast<CallExpr>(S), asc);
2034 
2035  case Stmt::CaseStmtClass:
2036  return VisitCaseStmt(cast<CaseStmt>(S));
2037 
2038  case Stmt::ChooseExprClass:
2039  return VisitChooseExpr(cast<ChooseExpr>(S), asc);
2040 
2041  case Stmt::CompoundStmtClass:
2042  return VisitCompoundStmt(cast<CompoundStmt>(S));
2043 
2044  case Stmt::ConditionalOperatorClass:
2045  return VisitConditionalOperator(cast<ConditionalOperator>(S), asc);
2046 
2047  case Stmt::ContinueStmtClass:
2048  return VisitContinueStmt(cast<ContinueStmt>(S));
2049 
2050  case Stmt::CXXCatchStmtClass:
2051  return VisitCXXCatchStmt(cast<CXXCatchStmt>(S));
2052 
2053  case Stmt::ExprWithCleanupsClass:
2054  return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc);
2055 
2056  case Stmt::CXXDefaultArgExprClass:
2057  case Stmt::CXXDefaultInitExprClass:
2058  // FIXME: The expression inside a CXXDefaultArgExpr is owned by the
2059  // called function's declaration, not by the caller. If we simply add
2060  // this expression to the CFG, we could end up with the same Expr
2061  // appearing multiple times.
2062  // PR13385 / <rdar://problem/12156507>
2063  //
2064  // It's likewise possible for multiple CXXDefaultInitExprs for the same
2065  // expression to be used in the same function (through aggregate
2066  // initialization).
2067  return VisitStmt(S, asc);
2068 
2069  case Stmt::CXXBindTemporaryExprClass:
2070  return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc);
2071 
2072  case Stmt::CXXConstructExprClass:
2073  return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc);
2074 
2075  case Stmt::CXXNewExprClass:
2076  return VisitCXXNewExpr(cast<CXXNewExpr>(S), asc);
2077 
2078  case Stmt::CXXDeleteExprClass:
2079  return VisitCXXDeleteExpr(cast<CXXDeleteExpr>(S), asc);
2080 
2081  case Stmt::CXXFunctionalCastExprClass:
2082  return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc);
2083 
2084  case Stmt::CXXTemporaryObjectExprClass:
2085  return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc);
2086 
2087  case Stmt::CXXThrowExprClass:
2088  return VisitCXXThrowExpr(cast<CXXThrowExpr>(S));
2089 
2090  case Stmt::CXXTryStmtClass:
2091  return VisitCXXTryStmt(cast<CXXTryStmt>(S));
2092 
2093  case Stmt::CXXForRangeStmtClass:
2094  return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S));
2095 
2096  case Stmt::DeclStmtClass:
2097  return VisitDeclStmt(cast<DeclStmt>(S));
2098 
2099  case Stmt::DefaultStmtClass:
2100  return VisitDefaultStmt(cast<DefaultStmt>(S));
2101 
2102  case Stmt::DoStmtClass:
2103  return VisitDoStmt(cast<DoStmt>(S));
2104 
2105  case Stmt::ForStmtClass:
2106  return VisitForStmt(cast<ForStmt>(S));
2107 
2108  case Stmt::GotoStmtClass:
2109  return VisitGotoStmt(cast<GotoStmt>(S));
2110 
2111  case Stmt::IfStmtClass:
2112  return VisitIfStmt(cast<IfStmt>(S));
2113 
2114  case Stmt::ImplicitCastExprClass:
2115  return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc);
2116 
2117  case Stmt::ConstantExprClass:
2118  return VisitConstantExpr(cast<ConstantExpr>(S), asc);
2119 
2120  case Stmt::IndirectGotoStmtClass:
2121  return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S));
2122 
2123  case Stmt::LabelStmtClass:
2124  return VisitLabelStmt(cast<LabelStmt>(S));
2125 
2126  case Stmt::LambdaExprClass:
2127  return VisitLambdaExpr(cast<LambdaExpr>(S), asc);
2128 
2129  case Stmt::MaterializeTemporaryExprClass:
2130  return VisitMaterializeTemporaryExpr(cast<MaterializeTemporaryExpr>(S),
2131  asc);
2132 
2133  case Stmt::MemberExprClass:
2134  return VisitMemberExpr(cast<MemberExpr>(S), asc);
2135 
2136  case Stmt::NullStmtClass:
2137  return Block;
2138 
2139  case Stmt::ObjCAtCatchStmtClass:
2140  return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S));
2141 
2142  case Stmt::ObjCAutoreleasePoolStmtClass:
2143  return VisitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(S));
2144 
2145  case Stmt::ObjCAtSynchronizedStmtClass:
2146  return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S));
2147 
2148  case Stmt::ObjCAtThrowStmtClass:
2149  return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S));
2150 
2151  case Stmt::ObjCAtTryStmtClass:
2152  return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S));
2153 
2154  case Stmt::ObjCForCollectionStmtClass:
2155  return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S));
2156 
2157  case Stmt::ObjCMessageExprClass:
2158  return VisitObjCMessageExpr(cast<ObjCMessageExpr>(S), asc);
2159 
2160  case Stmt::OpaqueValueExprClass:
2161  return Block;
2162 
2163  case Stmt::PseudoObjectExprClass:
2164  return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S));
2165 
2166  case Stmt::ReturnStmtClass:
2167  case Stmt::CoreturnStmtClass:
2168  return VisitReturnStmt(S);
2169 
2170  case Stmt::SEHExceptStmtClass:
2171  return VisitSEHExceptStmt(cast<SEHExceptStmt>(S));
2172 
2173  case Stmt::SEHFinallyStmtClass:
2174  return VisitSEHFinallyStmt(cast<SEHFinallyStmt>(S));
2175 
2176  case Stmt::SEHLeaveStmtClass:
2177  return VisitSEHLeaveStmt(cast<SEHLeaveStmt>(S));
2178 
2179  case Stmt::SEHTryStmtClass:
2180  return VisitSEHTryStmt(cast<SEHTryStmt>(S));
2181 
2182  case Stmt::UnaryExprOrTypeTraitExprClass:
2183  return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S),
2184  asc);
2185 
2186  case Stmt::StmtExprClass:
2187  return VisitStmtExpr(cast<StmtExpr>(S), asc);
2188 
2189  case Stmt::SwitchStmtClass:
2190  return VisitSwitchStmt(cast<SwitchStmt>(S));
2191 
2192  case Stmt::UnaryOperatorClass:
2193  return VisitUnaryOperator(cast<UnaryOperator>(S), asc);
2194 
2195  case Stmt::WhileStmtClass:
2196  return VisitWhileStmt(cast<WhileStmt>(S));
2197  }
2198 }
2199 
2200 CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) {
2201  if (asc.alwaysAdd(*this, S)) {
2202  autoCreateBlock();
2203  appendStmt(Block, S);
2204  }
2205 
2206  return VisitChildren(S);
2207 }
2208 
2209 /// VisitChildren - Visit the children of a Stmt.
2210 CFGBlock *CFGBuilder::VisitChildren(Stmt *S) {
2211  CFGBlock *B = Block;
2212 
2213  // Visit the children in their reverse order so that they appear in
2214  // left-to-right (natural) order in the CFG.
2215  reverse_children RChildren(S);
2216  for (reverse_children::iterator I = RChildren.begin(), E = RChildren.end();
2217  I != E; ++I) {
2218  if (Stmt *Child = *I)
2219  if (CFGBlock *R = Visit(Child))
2220  B = R;
2221  }
2222  return B;
2223 }
2224 
2225 CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A,
2226  AddStmtChoice asc) {
2227  AddressTakenLabels.insert(A->getLabel());
2228 
2229  if (asc.alwaysAdd(*this, A)) {
2230  autoCreateBlock();
2231  appendStmt(Block, A);
2232  }
2233 
2234  return Block;
2235 }
2236 
2237 CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U,
2238  AddStmtChoice asc) {
2239  if (asc.alwaysAdd(*this, U)) {
2240  autoCreateBlock();
2241  appendStmt(Block, U);
2242  }
2243 
2244  return Visit(U->getSubExpr(), AddStmtChoice());
2245 }
2246 
2247 CFGBlock *CFGBuilder::VisitLogicalOperator(BinaryOperator *B) {
2248  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2249  appendStmt(ConfluenceBlock, B);
2250 
2251  if (badCFG)
2252  return nullptr;
2253 
2254  return VisitLogicalOperator(B, nullptr, ConfluenceBlock,
2255  ConfluenceBlock).first;
2256 }
2257 
2258 std::pair<CFGBlock*, CFGBlock*>
2259 CFGBuilder::VisitLogicalOperator(BinaryOperator *B,
2260  Stmt *Term,
2261  CFGBlock *TrueBlock,
2262  CFGBlock *FalseBlock) {
2263  // Introspect the RHS. If it is a nested logical operation, we recursively
2264  // build the CFG using this function. Otherwise, resort to default
2265  // CFG construction behavior.
2266  Expr *RHS = B->getRHS()->IgnoreParens();
2267  CFGBlock *RHSBlock, *ExitBlock;
2268 
2269  do {
2270  if (BinaryOperator *B_RHS = dyn_cast<BinaryOperator>(RHS))
2271  if (B_RHS->isLogicalOp()) {
2272  std::tie(RHSBlock, ExitBlock) =
2273  VisitLogicalOperator(B_RHS, Term, TrueBlock, FalseBlock);
2274  break;
2275  }
2276 
2277  // The RHS is not a nested logical operation. Don't push the terminator
2278  // down further, but instead visit RHS and construct the respective
2279  // pieces of the CFG, and link up the RHSBlock with the terminator
2280  // we have been provided.
2281  ExitBlock = RHSBlock = createBlock(false);
2282 
2283  // Even though KnownVal is only used in the else branch of the next
2284  // conditional, tryEvaluateBool performs additional checking on the
2285  // Expr, so it should be called unconditionally.
2286  TryResult KnownVal = tryEvaluateBool(RHS);
2287  if (!KnownVal.isKnown())
2288  KnownVal = tryEvaluateBool(B);
2289 
2290  if (!Term) {
2291  assert(TrueBlock == FalseBlock);
2292  addSuccessor(RHSBlock, TrueBlock);
2293  }
2294  else {
2295  RHSBlock->setTerminator(Term);
2296  addSuccessor(RHSBlock, TrueBlock, !KnownVal.isFalse());
2297  addSuccessor(RHSBlock, FalseBlock, !KnownVal.isTrue());
2298  }
2299 
2300  Block = RHSBlock;
2301  RHSBlock = addStmt(RHS);
2302  }
2303  while (false);
2304 
2305  if (badCFG)
2306  return std::make_pair(nullptr, nullptr);
2307 
2308  // Generate the blocks for evaluating the LHS.
2309  Expr *LHS = B->getLHS()->IgnoreParens();
2310 
2311  if (BinaryOperator *B_LHS = dyn_cast<BinaryOperator>(LHS))
2312  if (B_LHS->isLogicalOp()) {
2313  if (B->getOpcode() == BO_LOr)
2314  FalseBlock = RHSBlock;
2315  else
2316  TrueBlock = RHSBlock;
2317 
2318  // For the LHS, treat 'B' as the terminator that we want to sink
2319  // into the nested branch. The RHS always gets the top-most
2320  // terminator.
2321  return VisitLogicalOperator(B_LHS, B, TrueBlock, FalseBlock);
2322  }
2323 
2324  // Create the block evaluating the LHS.
2325  // This contains the '&&' or '||' as the terminator.
2326  CFGBlock *LHSBlock = createBlock(false);
2327  LHSBlock->setTerminator(B);
2328 
2329  Block = LHSBlock;
2330  CFGBlock *EntryLHSBlock = addStmt(LHS);
2331 
2332  if (badCFG)
2333  return std::make_pair(nullptr, nullptr);
2334 
2335  // See if this is a known constant.
2336  TryResult KnownVal = tryEvaluateBool(LHS);
2337 
2338  // Now link the LHSBlock with RHSBlock.
2339  if (B->getOpcode() == BO_LOr) {
2340  addSuccessor(LHSBlock, TrueBlock, !KnownVal.isFalse());
2341  addSuccessor(LHSBlock, RHSBlock, !KnownVal.isTrue());
2342  } else {
2343  assert(B->getOpcode() == BO_LAnd);
2344  addSuccessor(LHSBlock, RHSBlock, !KnownVal.isFalse());
2345  addSuccessor(LHSBlock, FalseBlock, !KnownVal.isTrue());
2346  }
2347 
2348  return std::make_pair(EntryLHSBlock, ExitBlock);
2349 }
2350 
2351 CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B,
2352  AddStmtChoice asc) {
2353  // && or ||
2354  if (B->isLogicalOp())
2355  return VisitLogicalOperator(B);
2356 
2357  if (B->getOpcode() == BO_Comma) { // ,
2358  autoCreateBlock();
2359  appendStmt(Block, B);
2360  addStmt(B->getRHS());
2361  return addStmt(B->getLHS());
2362  }
2363 
2364  if (B->isAssignmentOp()) {
2365  if (asc.alwaysAdd(*this, B)) {
2366  autoCreateBlock();
2367  appendStmt(Block, B);
2368  }
2369  Visit(B->getLHS());
2370  return Visit(B->getRHS());
2371  }
2372 
2373  if (asc.alwaysAdd(*this, B)) {
2374  autoCreateBlock();
2375  appendStmt(Block, B);
2376  }
2377 
2378  CFGBlock *RBlock = Visit(B->getRHS());
2379  CFGBlock *LBlock = Visit(B->getLHS());
2380  // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr
2381  // containing a DoStmt, and the LHS doesn't create a new block, then we should
2382  // return RBlock. Otherwise we'll incorrectly return NULL.
2383  return (LBlock ? LBlock : RBlock);
2384 }
2385 
2386 CFGBlock *CFGBuilder::VisitNoRecurse(Expr *E, AddStmtChoice asc) {
2387  if (asc.alwaysAdd(*this, E)) {
2388  autoCreateBlock();
2389  appendStmt(Block, E);
2390  }
2391  return Block;
2392 }
2393 
2394 CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) {
2395  // "break" is a control-flow statement. Thus we stop processing the current
2396  // block.
2397  if (badCFG)
2398  return nullptr;
2399 
2400  // Now create a new block that ends with the break statement.
2401  Block = createBlock(false);
2402  Block->setTerminator(B);
2403 
2404  // If there is no target for the break, then we are looking at an incomplete
2405  // AST. This means that the CFG cannot be constructed.
2406  if (BreakJumpTarget.block) {
2407  addAutomaticObjHandling(ScopePos, BreakJumpTarget.scopePosition, B);
2408  addSuccessor(Block, BreakJumpTarget.block);
2409  } else
2410  badCFG = true;
2411 
2412  return Block;
2413 }
2414 
2415 static bool CanThrow(Expr *E, ASTContext &Ctx) {
2416  QualType Ty = E->getType();
2417  if (Ty->isFunctionPointerType())
2418  Ty = Ty->getAs<PointerType>()->getPointeeType();
2419  else if (Ty->isBlockPointerType())
2420  Ty = Ty->getAs<BlockPointerType>()->getPointeeType();
2421 
2422  const FunctionType *FT = Ty->getAs<FunctionType>();
2423  if (FT) {
2424  if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT))
2425  if (!isUnresolvedExceptionSpec(Proto->getExceptionSpecType()) &&
2426  Proto->isNothrow())
2427  return false;
2428  }
2429  return true;
2430 }
2431 
2432 CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) {
2433  // Compute the callee type.
2434  QualType calleeType = C->getCallee()->getType();
2435  if (calleeType == Context->BoundMemberTy) {
2436  QualType boundType = Expr::findBoundMemberType(C->getCallee());
2437 
2438  // We should only get a null bound type if processing a dependent
2439  // CFG. Recover by assuming nothing.
2440  if (!boundType.isNull()) calleeType = boundType;
2441  }
2442 
2443  // If this is a call to a no-return function, this stops the block here.
2444  bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn();
2445 
2446  bool AddEHEdge = false;
2447 
2448  // Languages without exceptions are assumed to not throw.
2449  if (Context->getLangOpts().Exceptions) {
2450  if (BuildOpts.AddEHEdges)
2451  AddEHEdge = true;
2452  }
2453 
2454  // If this is a call to a builtin function, it might not actually evaluate
2455  // its arguments. Don't add them to the CFG if this is the case.
2456  bool OmitArguments = false;
2457 
2458  if (FunctionDecl *FD = C->getDirectCallee()) {
2459  // TODO: Support construction contexts for variadic function arguments.
2460  // These are a bit problematic and not very useful because passing
2461  // C++ objects as C-style variadic arguments doesn't work in general
2462  // (see [expr.call]).
2463  if (!FD->isVariadic())
2464  findConstructionContextsForArguments(C);
2465 
2466  if (FD->isNoReturn() || C->isBuiltinAssumeFalse(*Context))
2467  NoReturn = true;
2468  if (FD->hasAttr<NoThrowAttr>())
2469  AddEHEdge = false;
2470  if (FD->getBuiltinID() == Builtin::BI__builtin_object_size ||
2471  FD->getBuiltinID() == Builtin::BI__builtin_dynamic_object_size)
2472  OmitArguments = true;
2473  }
2474 
2475  if (!CanThrow(C->getCallee(), *Context))
2476  AddEHEdge = false;
2477 
2478  if (OmitArguments) {
2479  assert(!NoReturn && "noreturn calls with unevaluated args not implemented");
2480  assert(!AddEHEdge && "EH calls with unevaluated args not implemented");
2481  autoCreateBlock();
2482  appendStmt(Block, C);
2483  return Visit(C->getCallee());
2484  }
2485 
2486  if (!NoReturn && !AddEHEdge) {
2487  autoCreateBlock();
2488  appendCall(Block, C);
2489 
2490  return VisitChildren(C);
2491  }
2492 
2493  if (Block) {
2494  Succ = Block;
2495  if (badCFG)
2496  return nullptr;
2497  }
2498 
2499  if (NoReturn)
2500  Block = createNoReturnBlock();
2501  else
2502  Block = createBlock();
2503 
2504  appendCall(Block, C);
2505 
2506  if (AddEHEdge) {
2507  // Add exceptional edges.
2508  if (TryTerminatedBlock)
2509  addSuccessor(Block, TryTerminatedBlock);
2510  else
2511  addSuccessor(Block, &cfg->getExit());
2512  }
2513 
2514  return VisitChildren(C);
2515 }
2516 
2517 CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C,
2518  AddStmtChoice asc) {
2519  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2520  appendStmt(ConfluenceBlock, C);
2521  if (badCFG)
2522  return nullptr;
2523 
2524  AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2525  Succ = ConfluenceBlock;
2526  Block = nullptr;
2527  CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd);
2528  if (badCFG)
2529  return nullptr;
2530 
2531  Succ = ConfluenceBlock;
2532  Block = nullptr;
2533  CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd);
2534  if (badCFG)
2535  return nullptr;
2536 
2537  Block = createBlock(false);
2538  // See if this is a known constant.
2539  const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2540  addSuccessor(Block, KnownVal.isFalse() ? nullptr : LHSBlock);
2541  addSuccessor(Block, KnownVal.isTrue() ? nullptr : RHSBlock);
2542  Block->setTerminator(C);
2543  return addStmt(C->getCond());
2544 }
2545 
2546 CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) {
2547  LocalScope::const_iterator scopeBeginPos = ScopePos;
2548  addLocalScopeForStmt(C);
2549 
2550  if (!C->body_empty() && !isa<ReturnStmt>(*C->body_rbegin())) {
2551  // If the body ends with a ReturnStmt, the dtors will be added in
2552  // VisitReturnStmt.
2553  addAutomaticObjHandling(ScopePos, scopeBeginPos, C);
2554  }
2555 
2556  CFGBlock *LastBlock = Block;
2557 
2559  I != E; ++I ) {
2560  // If we hit a segment of code just containing ';' (NullStmts), we can
2561  // get a null block back. In such cases, just use the LastBlock
2562  if (CFGBlock *newBlock = addStmt(*I))
2563  LastBlock = newBlock;
2564 
2565  if (badCFG)
2566  return nullptr;
2567  }
2568 
2569  return LastBlock;
2570 }
2571 
2572 CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C,
2573  AddStmtChoice asc) {
2574  const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C);
2575  const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : nullptr);
2576 
2577  // Create the confluence block that will "merge" the results of the ternary
2578  // expression.
2579  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2580  appendStmt(ConfluenceBlock, C);
2581  if (badCFG)
2582  return nullptr;
2583 
2584  AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2585 
2586  // Create a block for the LHS expression if there is an LHS expression. A
2587  // GCC extension allows LHS to be NULL, causing the condition to be the
2588  // value that is returned instead.
2589  // e.g: x ?: y is shorthand for: x ? x : y;
2590  Succ = ConfluenceBlock;
2591  Block = nullptr;
2592  CFGBlock *LHSBlock = nullptr;
2593  const Expr *trueExpr = C->getTrueExpr();
2594  if (trueExpr != opaqueValue) {
2595  LHSBlock = Visit(C->getTrueExpr(), alwaysAdd);
2596  if (badCFG)
2597  return nullptr;
2598  Block = nullptr;
2599  }
2600  else
2601  LHSBlock = ConfluenceBlock;
2602 
2603  // Create the block for the RHS expression.
2604  Succ = ConfluenceBlock;
2605  CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd);
2606  if (badCFG)
2607  return nullptr;
2608 
2609  // If the condition is a logical '&&' or '||', build a more accurate CFG.
2610  if (BinaryOperator *Cond =
2611  dyn_cast<BinaryOperator>(C->getCond()->IgnoreParens()))
2612  if (Cond->isLogicalOp())
2613  return VisitLogicalOperator(Cond, C, LHSBlock, RHSBlock).first;
2614 
2615  // Create the block that will contain the condition.
2616  Block = createBlock(false);
2617 
2618  // See if this is a known constant.
2619  const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2620  addSuccessor(Block, LHSBlock, !KnownVal.isFalse());
2621  addSuccessor(Block, RHSBlock, !KnownVal.isTrue());
2622  Block->setTerminator(C);
2623  Expr *condExpr = C->getCond();
2624 
2625  if (opaqueValue) {
2626  // Run the condition expression if it's not trivially expressed in
2627  // terms of the opaque value (or if there is no opaque value).
2628  if (condExpr != opaqueValue)
2629  addStmt(condExpr);
2630 
2631  // Before that, run the common subexpression if there was one.
2632  // At least one of this or the above will be run.
2633  return addStmt(BCO->getCommon());
2634  }
2635 
2636  return addStmt(condExpr);
2637 }
2638 
2639 CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) {
2640  // Check if the Decl is for an __label__. If so, elide it from the
2641  // CFG entirely.
2642  if (isa<LabelDecl>(*DS->decl_begin()))
2643  return Block;
2644 
2645  // This case also handles static_asserts.
2646  if (DS->isSingleDecl())
2647  return VisitDeclSubExpr(DS);
2648 
2649  CFGBlock *B = nullptr;
2650 
2651  // Build an individual DeclStmt for each decl.
2653  E = DS->decl_rend();
2654  I != E; ++I) {
2655 
2656  // Allocate the DeclStmt using the BumpPtrAllocator. It will get
2657  // automatically freed with the CFG.
2658  DeclGroupRef DG(*I);
2659  Decl *D = *I;
2660  DeclStmt *DSNew = new (Context) DeclStmt(DG, D->getLocation(), GetEndLoc(D));
2661  cfg->addSyntheticDeclStmt(DSNew, DS);
2662 
2663  // Append the fake DeclStmt to block.
2664  B = VisitDeclSubExpr(DSNew);
2665  }
2666 
2667  return B;
2668 }
2669 
2670 /// VisitDeclSubExpr - Utility method to add block-level expressions for
2671 /// DeclStmts and initializers in them.
2672 CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) {
2673  assert(DS->isSingleDecl() && "Can handle single declarations only.");
2674  VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl());
2675 
2676  if (!VD) {
2677  // Of everything that can be declared in a DeclStmt, only VarDecls impact
2678  // runtime semantics.
2679  return Block;
2680  }
2681 
2682  bool HasTemporaries = false;
2683 
2684  // Guard static initializers under a branch.
2685  CFGBlock *blockAfterStaticInit = nullptr;
2686 
2687  if (BuildOpts.AddStaticInitBranches && VD->isStaticLocal()) {
2688  // For static variables, we need to create a branch to track
2689  // whether or not they are initialized.
2690  if (Block) {
2691  Succ = Block;
2692  Block = nullptr;
2693  if (badCFG)
2694  return nullptr;
2695  }
2696  blockAfterStaticInit = Succ;
2697  }
2698 
2699  // Destructors of temporaries in initialization expression should be called
2700  // after initialization finishes.
2701  Expr *Init = VD->getInit();
2702  if (Init) {
2703  HasTemporaries = isa<ExprWithCleanups>(Init);
2704 
2705  if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
2706  // Generate destructors for temporaries in initialization expression.
2707  TempDtorContext Context;
2708  VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
2709  /*BindToTemporary=*/false, Context);
2710  }
2711  }
2712 
2713  autoCreateBlock();
2714  appendStmt(Block, DS);
2715 
2716  findConstructionContexts(
2717  ConstructionContextLayer::create(cfg->getBumpVectorContext(), DS),
2718  Init);
2719 
2720  // Keep track of the last non-null block, as 'Block' can be nulled out
2721  // if the initializer expression is something like a 'while' in a
2722  // statement-expression.
2723  CFGBlock *LastBlock = Block;
2724 
2725  if (Init) {
2726  if (HasTemporaries) {
2727  // For expression with temporaries go directly to subexpression to omit
2728  // generating destructors for the second time.
2729  ExprWithCleanups *EC = cast<ExprWithCleanups>(Init);
2730  if (CFGBlock *newBlock = Visit(EC->getSubExpr()))
2731  LastBlock = newBlock;
2732  }
2733  else {
2734  if (CFGBlock *newBlock = Visit(Init))
2735  LastBlock = newBlock;
2736  }
2737  }
2738 
2739  // If the type of VD is a VLA, then we must process its size expressions.
2740  for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr());
2741  VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr())) {
2742  if (CFGBlock *newBlock = addStmt(VA->getSizeExpr()))
2743  LastBlock = newBlock;
2744  }
2745 
2746  maybeAddScopeBeginForVarDecl(Block, VD, DS);
2747 
2748  // Remove variable from local scope.
2749  if (ScopePos && VD == *ScopePos)
2750  ++ScopePos;
2751 
2752  CFGBlock *B = LastBlock;
2753  if (blockAfterStaticInit) {
2754  Succ = B;
2755  Block = createBlock(false);
2756  Block->setTerminator(DS);
2757  addSuccessor(Block, blockAfterStaticInit);
2758  addSuccessor(Block, B);
2759  B = Block;
2760  }
2761 
2762  return B;
2763 }
2764 
2765 CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) {
2766  // We may see an if statement in the middle of a basic block, or it may be the
2767  // first statement we are processing. In either case, we create a new basic
2768  // block. First, we create the blocks for the then...else statements, and
2769  // then we create the block containing the if statement. If we were in the
2770  // middle of a block, we stop processing that block. That block is then the
2771  // implicit successor for the "then" and "else" clauses.
2772 
2773  // Save local scope position because in case of condition variable ScopePos
2774  // won't be restored when traversing AST.
2775  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2776 
2777  // Create local scope for C++17 if init-stmt if one exists.
2778  if (Stmt *Init = I->getInit())
2779  addLocalScopeForStmt(Init);
2780 
2781  // Create local scope for possible condition variable.
2782  // Store scope position. Add implicit destructor.
2783  if (VarDecl *VD = I->getConditionVariable())
2784  addLocalScopeForVarDecl(VD);
2785 
2786  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), I);
2787 
2788  // The block we were processing is now finished. Make it the successor
2789  // block.
2790  if (Block) {
2791  Succ = Block;
2792  if (badCFG)
2793  return nullptr;
2794  }
2795 
2796  // Process the false branch.
2797  CFGBlock *ElseBlock = Succ;
2798 
2799  if (Stmt *Else = I->getElse()) {
2800  SaveAndRestore<CFGBlock*> sv(Succ);
2801 
2802  // NULL out Block so that the recursive call to Visit will
2803  // create a new basic block.
2804  Block = nullptr;
2805 
2806  // If branch is not a compound statement create implicit scope
2807  // and add destructors.
2808  if (!isa<CompoundStmt>(Else))
2809  addLocalScopeAndDtors(Else);
2810 
2811  ElseBlock = addStmt(Else);
2812 
2813  if (!ElseBlock) // Can occur when the Else body has all NullStmts.
2814  ElseBlock = sv.get();
2815  else if (Block) {
2816  if (badCFG)
2817  return nullptr;
2818  }
2819  }
2820 
2821  // Process the true branch.
2822  CFGBlock *ThenBlock;
2823  {
2824  Stmt *Then = I->getThen();
2825  assert(Then);
2826  SaveAndRestore<CFGBlock*> sv(Succ);
2827  Block = nullptr;
2828 
2829  // If branch is not a compound statement create implicit scope
2830  // and add destructors.
2831  if (!isa<CompoundStmt>(Then))
2832  addLocalScopeAndDtors(Then);
2833 
2834  ThenBlock = addStmt(Then);
2835 
2836  if (!ThenBlock) {
2837  // We can reach here if the "then" body has all NullStmts.
2838  // Create an empty block so we can distinguish between true and false
2839  // branches in path-sensitive analyses.
2840  ThenBlock = createBlock(false);
2841  addSuccessor(ThenBlock, sv.get());
2842  } else if (Block) {
2843  if (badCFG)
2844  return nullptr;
2845  }
2846  }
2847 
2848  // Specially handle "if (expr1 || ...)" and "if (expr1 && ...)" by
2849  // having these handle the actual control-flow jump. Note that
2850  // if we introduce a condition variable, e.g. "if (int x = exp1 || exp2)"
2851  // we resort to the old control-flow behavior. This special handling
2852  // removes infeasible paths from the control-flow graph by having the
2853  // control-flow transfer of '&&' or '||' go directly into the then/else
2854  // blocks directly.
2855  BinaryOperator *Cond =
2857  ? nullptr
2858  : dyn_cast<BinaryOperator>(I->getCond()->IgnoreParens());
2859  CFGBlock *LastBlock;
2860  if (Cond && Cond->isLogicalOp())
2861  LastBlock = VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first;
2862  else {
2863  // Now create a new block containing the if statement.
2864  Block = createBlock(false);
2865 
2866  // Set the terminator of the new block to the If statement.
2867  Block->setTerminator(I);
2868 
2869  // See if this is a known constant.
2870  const TryResult &KnownVal = tryEvaluateBool(I->getCond());
2871 
2872  // Add the successors. If we know that specific branches are
2873  // unreachable, inform addSuccessor() of that knowledge.
2874  addSuccessor(Block, ThenBlock, /* isReachable = */ !KnownVal.isFalse());
2875  addSuccessor(Block, ElseBlock, /* isReachable = */ !KnownVal.isTrue());
2876 
2877  // Add the condition as the last statement in the new block. This may
2878  // create new blocks as the condition may contain control-flow. Any newly
2879  // created blocks will be pointed to be "Block".
2880  LastBlock = addStmt(I->getCond());
2881 
2882  // If the IfStmt contains a condition variable, add it and its
2883  // initializer to the CFG.
2884  if (const DeclStmt* DS = I->getConditionVariableDeclStmt()) {
2885  autoCreateBlock();
2886  LastBlock = addStmt(const_cast<DeclStmt *>(DS));
2887  }
2888  }
2889 
2890  // Finally, if the IfStmt contains a C++17 init-stmt, add it to the CFG.
2891  if (Stmt *Init = I->getInit()) {
2892  autoCreateBlock();
2893  LastBlock = addStmt(Init);
2894  }
2895 
2896  return LastBlock;
2897 }
2898 
2899 CFGBlock *CFGBuilder::VisitReturnStmt(Stmt *S) {
2900  // If we were in the middle of a block we stop processing that block.
2901  //
2902  // NOTE: If a "return" or "co_return" appears in the middle of a block, this
2903  // means that the code afterwards is DEAD (unreachable). We still keep
2904  // a basic block for that code; a simple "mark-and-sweep" from the entry
2905  // block will be able to report such dead blocks.
2906  assert(isa<ReturnStmt>(S) || isa<CoreturnStmt>(S));
2907 
2908  // Create the new block.
2909  Block = createBlock(false);
2910 
2911  addAutomaticObjHandling(ScopePos, LocalScope::const_iterator(), S);
2912 
2913  if (auto *R = dyn_cast<ReturnStmt>(S))
2914  findConstructionContexts(
2915  ConstructionContextLayer::create(cfg->getBumpVectorContext(), R),
2916  R->getRetValue());
2917 
2918  // If the one of the destructors does not return, we already have the Exit
2919  // block as a successor.
2920  if (!Block->hasNoReturnElement())
2921  addSuccessor(Block, &cfg->getExit());
2922 
2923  // Add the return statement to the block. This may create new blocks if R
2924  // contains control-flow (short-circuit operations).
2925  return VisitStmt(S, AddStmtChoice::AlwaysAdd);
2926 }
2927 
2928 CFGBlock *CFGBuilder::VisitSEHExceptStmt(SEHExceptStmt *ES) {
2929  // SEHExceptStmt are treated like labels, so they are the first statement in a
2930  // block.
2931 
2932  // Save local scope position because in case of exception variable ScopePos
2933  // won't be restored when traversing AST.
2934  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2935 
2936  addStmt(ES->getBlock());
2937  CFGBlock *SEHExceptBlock = Block;
2938  if (!SEHExceptBlock)
2939  SEHExceptBlock = createBlock();
2940 
2941  appendStmt(SEHExceptBlock, ES);
2942 
2943  // Also add the SEHExceptBlock as a label, like with regular labels.
2944  SEHExceptBlock->setLabel(ES);
2945 
2946  // Bail out if the CFG is bad.
2947  if (badCFG)
2948  return nullptr;
2949 
2950  // We set Block to NULL to allow lazy creation of a new block (if necessary).
2951  Block = nullptr;
2952 
2953  return SEHExceptBlock;
2954 }
2955 
2956 CFGBlock *CFGBuilder::VisitSEHFinallyStmt(SEHFinallyStmt *FS) {
2957  return VisitCompoundStmt(FS->getBlock());
2958 }
2959 
2960 CFGBlock *CFGBuilder::VisitSEHLeaveStmt(SEHLeaveStmt *LS) {
2961  // "__leave" is a control-flow statement. Thus we stop processing the current
2962  // block.
2963  if (badCFG)
2964  return nullptr;
2965 
2966  // Now create a new block that ends with the __leave statement.
2967  Block = createBlock(false);
2968  Block->setTerminator(LS);
2969 
2970  // If there is no target for the __leave, then we are looking at an incomplete
2971  // AST. This means that the CFG cannot be constructed.
2972  if (SEHLeaveJumpTarget.block) {
2973  addAutomaticObjHandling(ScopePos, SEHLeaveJumpTarget.scopePosition, LS);
2974  addSuccessor(Block, SEHLeaveJumpTarget.block);
2975  } else
2976  badCFG = true;
2977 
2978  return Block;
2979 }
2980 
2981 CFGBlock *CFGBuilder::VisitSEHTryStmt(SEHTryStmt *Terminator) {
2982  // "__try"/"__except"/"__finally" is a control-flow statement. Thus we stop
2983  // processing the current block.
2984  CFGBlock *SEHTrySuccessor = nullptr;
2985 
2986  if (Block) {
2987  if (badCFG)
2988  return nullptr;
2989  SEHTrySuccessor = Block;
2990  } else SEHTrySuccessor = Succ;
2991 
2992  // FIXME: Implement __finally support.
2993  if (Terminator->getFinallyHandler())
2994  return NYS();
2995 
2996  CFGBlock *PrevSEHTryTerminatedBlock = TryTerminatedBlock;
2997 
2998  // Create a new block that will contain the __try statement.
2999  CFGBlock *NewTryTerminatedBlock = createBlock(false);
3000 
3001  // Add the terminator in the __try block.
3002  NewTryTerminatedBlock->setTerminator(Terminator);
3003 
3004  if (SEHExceptStmt *Except = Terminator->getExceptHandler()) {
3005  // The code after the try is the implicit successor if there's an __except.
3006  Succ = SEHTrySuccessor;
3007  Block = nullptr;
3008  CFGBlock *ExceptBlock = VisitSEHExceptStmt(Except);
3009  if (!ExceptBlock)
3010  return nullptr;
3011  // Add this block to the list of successors for the block with the try
3012  // statement.
3013  addSuccessor(NewTryTerminatedBlock, ExceptBlock);
3014  }
3015  if (PrevSEHTryTerminatedBlock)
3016  addSuccessor(NewTryTerminatedBlock, PrevSEHTryTerminatedBlock);
3017  else
3018  addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
3019 
3020  // The code after the try is the implicit successor.
3021  Succ = SEHTrySuccessor;
3022 
3023  // Save the current "__try" context.
3024  SaveAndRestore<CFGBlock *> save_try(TryTerminatedBlock,
3025  NewTryTerminatedBlock);
3026  cfg->addTryDispatchBlock(TryTerminatedBlock);
3027 
3028  // Save the current value for the __leave target.
3029  // All __leaves should go to the code following the __try
3030  // (FIXME: or if the __try has a __finally, to the __finally.)
3031  SaveAndRestore<JumpTarget> save_break(SEHLeaveJumpTarget);
3032  SEHLeaveJumpTarget = JumpTarget(SEHTrySuccessor, ScopePos);
3033 
3034  assert(Terminator->getTryBlock() && "__try must contain a non-NULL body");
3035  Block = nullptr;
3036  return addStmt(Terminator->getTryBlock());
3037 }
3038 
3039 CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) {
3040  // Get the block of the labeled statement. Add it to our map.
3041  addStmt(L->getSubStmt());
3042  CFGBlock *LabelBlock = Block;
3043 
3044  if (!LabelBlock) // This can happen when the body is empty, i.e.
3045  LabelBlock = createBlock(); // scopes that only contains NullStmts.
3046 
3047  assert(LabelMap.find(L->getDecl()) == LabelMap.end() &&
3048  "label already in map");
3049  LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos);
3050 
3051  // Labels partition blocks, so this is the end of the basic block we were
3052  // processing (L is the block's label). Because this is label (and we have
3053  // already processed the substatement) there is no extra control-flow to worry
3054  // about.
3055  LabelBlock->setLabel(L);
3056  if (badCFG)
3057  return nullptr;
3058 
3059  // We set Block to NULL to allow lazy creation of a new block (if necessary);
3060  Block = nullptr;
3061 
3062  // This block is now the implicit successor of other blocks.
3063  Succ = LabelBlock;
3064 
3065  return LabelBlock;
3066 }
3067 
3068 CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) {
3069  CFGBlock *LastBlock = VisitNoRecurse(E, asc);
3070  for (const BlockDecl::Capture &CI : E->getBlockDecl()->captures()) {
3071  if (Expr *CopyExpr = CI.getCopyExpr()) {
3072  CFGBlock *Tmp = Visit(CopyExpr);
3073  if (Tmp)
3074  LastBlock = Tmp;
3075  }
3076  }
3077  return LastBlock;
3078 }
3079 
3080 CFGBlock *CFGBuilder::VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc) {
3081  CFGBlock *LastBlock = VisitNoRecurse(E, asc);
3083  et = E->capture_init_end(); it != et; ++it) {
3084  if (Expr *Init = *it) {
3085  CFGBlock *Tmp = Visit(Init);
3086  if (Tmp)
3087  LastBlock = Tmp;
3088  }
3089  }
3090  return LastBlock;
3091 }
3092 
3093 CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) {
3094  // Goto is a control-flow statement. Thus we stop processing the current
3095  // block and create a new one.
3096 
3097  Block = createBlock(false);
3098  Block->setTerminator(G);
3099 
3100  // If we already know the mapping to the label block add the successor now.
3101  LabelMapTy::iterator I = LabelMap.find(G->getLabel());
3102 
3103  if (I == LabelMap.end())
3104  // We will need to backpatch this block later.
3105  BackpatchBlocks.push_back(JumpSource(Block, ScopePos));
3106  else {
3107  JumpTarget JT = I->second;
3108  addAutomaticObjHandling(ScopePos, JT.scopePosition, G);
3109  addSuccessor(Block, JT.block);
3110  }
3111 
3112  return Block;
3113 }
3114 
3115 CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) {
3116  CFGBlock *LoopSuccessor = nullptr;
3117 
3118  // Save local scope position because in case of condition variable ScopePos
3119  // won't be restored when traversing AST.
3120  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3121 
3122  // Create local scope for init statement and possible condition variable.
3123  // Add destructor for init statement and condition variable.
3124  // Store scope position for continue statement.
3125  if (Stmt *Init = F->getInit())
3126  addLocalScopeForStmt(Init);
3127  LocalScope::const_iterator LoopBeginScopePos = ScopePos;
3128 
3129  if (VarDecl *VD = F->getConditionVariable())
3130  addLocalScopeForVarDecl(VD);
3131  LocalScope::const_iterator ContinueScopePos = ScopePos;
3132 
3133  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), F);
3134 
3135  addLoopExit(F);
3136 
3137  // "for" is a control-flow statement. Thus we stop processing the current
3138  // block.
3139  if (Block) {
3140  if (badCFG)
3141  return nullptr;
3142  LoopSuccessor = Block;
3143  } else
3144  LoopSuccessor = Succ;
3145 
3146  // Save the current value for the break targets.
3147  // All breaks should go to the code following the loop.
3148  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3149  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3150 
3151  CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
3152 
3153  // Now create the loop body.
3154  {
3155  assert(F->getBody());
3156 
3157  // Save the current values for Block, Succ, continue and break targets.
3158  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3159  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
3160 
3161  // Create an empty block to represent the transition block for looping back
3162  // to the head of the loop. If we have increment code, it will
3163  // go in this block as well.
3164  Block = Succ = TransitionBlock = createBlock(false);
3165  TransitionBlock->setLoopTarget(F);
3166 
3167  if (Stmt *I = F->getInc()) {
3168  // Generate increment code in its own basic block. This is the target of
3169  // continue statements.
3170  Succ = addStmt(I);
3171  }
3172 
3173  // Finish up the increment (or empty) block if it hasn't been already.
3174  if (Block) {
3175  assert(Block == Succ);
3176  if (badCFG)
3177  return nullptr;
3178  Block = nullptr;
3179  }
3180 
3181  // The starting block for the loop increment is the block that should
3182  // represent the 'loop target' for looping back to the start of the loop.
3183  ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
3184  ContinueJumpTarget.block->setLoopTarget(F);
3185 
3186  // Loop body should end with destructor of Condition variable (if any).
3187  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, F);
3188 
3189  // If body is not a compound statement create implicit scope
3190  // and add destructors.
3191  if (!isa<CompoundStmt>(F->getBody()))
3192  addLocalScopeAndDtors(F->getBody());
3193 
3194  // Now populate the body block, and in the process create new blocks as we
3195  // walk the body of the loop.
3196  BodyBlock = addStmt(F->getBody());
3197 
3198  if (!BodyBlock) {
3199  // In the case of "for (...;...;...);" we can have a null BodyBlock.
3200  // Use the continue jump target as the proxy for the body.
3201  BodyBlock = ContinueJumpTarget.block;
3202  }
3203  else if (badCFG)
3204  return nullptr;
3205  }
3206 
3207  // Because of short-circuit evaluation, the condition of the loop can span
3208  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3209  // evaluate the condition.
3210  CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
3211 
3212  do {
3213  Expr *C = F->getCond();
3214  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3215 
3216  // Specially handle logical operators, which have a slightly
3217  // more optimal CFG representation.
3218  if (BinaryOperator *Cond =
3219  dyn_cast_or_null<BinaryOperator>(C ? C->IgnoreParens() : nullptr))
3220  if (Cond->isLogicalOp()) {
3221  std::tie(EntryConditionBlock, ExitConditionBlock) =
3222  VisitLogicalOperator(Cond, F, BodyBlock, LoopSuccessor);
3223  break;
3224  }
3225 
3226  // The default case when not handling logical operators.
3227  EntryConditionBlock = ExitConditionBlock = createBlock(false);
3228  ExitConditionBlock->setTerminator(F);
3229 
3230  // See if this is a known constant.
3231  TryResult KnownVal(true);
3232 
3233  if (C) {
3234  // Now add the actual condition to the condition block.
3235  // Because the condition itself may contain control-flow, new blocks may
3236  // be created. Thus we update "Succ" after adding the condition.
3237  Block = ExitConditionBlock;
3238  EntryConditionBlock = addStmt(C);
3239 
3240  // If this block contains a condition variable, add both the condition
3241  // variable and initializer to the CFG.
3242  if (VarDecl *VD = F->getConditionVariable()) {
3243  if (Expr *Init = VD->getInit()) {
3244  autoCreateBlock();
3245  const DeclStmt *DS = F->getConditionVariableDeclStmt();
3246  assert(DS->isSingleDecl());
3247  findConstructionContexts(
3248  ConstructionContextLayer::create(cfg->getBumpVectorContext(), DS),
3249  Init);
3250  appendStmt(Block, DS);
3251  EntryConditionBlock = addStmt(Init);
3252  assert(Block == EntryConditionBlock);
3253  maybeAddScopeBeginForVarDecl(EntryConditionBlock, VD, C);
3254  }
3255  }
3256 
3257  if (Block && badCFG)
3258  return nullptr;
3259 
3260  KnownVal = tryEvaluateBool(C);
3261  }
3262 
3263  // Add the loop body entry as a successor to the condition.
3264  addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
3265  // Link up the condition block with the code that follows the loop. (the
3266  // false branch).
3267  addSuccessor(ExitConditionBlock,
3268  KnownVal.isTrue() ? nullptr : LoopSuccessor);
3269  } while (false);
3270 
3271  // Link up the loop-back block to the entry condition block.
3272  addSuccessor(TransitionBlock, EntryConditionBlock);
3273 
3274  // The condition block is the implicit successor for any code above the loop.
3275  Succ = EntryConditionBlock;
3276 
3277  // If the loop contains initialization, create a new block for those
3278  // statements. This block can also contain statements that precede the loop.
3279  if (Stmt *I = F->getInit()) {
3280  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3281  ScopePos = LoopBeginScopePos;
3282  Block = createBlock();
3283  return addStmt(I);
3284  }
3285 
3286  // There is no loop initialization. We are thus basically a while loop.
3287  // NULL out Block to force lazy block construction.
3288  Block = nullptr;
3289  Succ = EntryConditionBlock;
3290  return EntryConditionBlock;
3291 }
3292 
3293 CFGBlock *
3294 CFGBuilder::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *MTE,
3295  AddStmtChoice asc) {
3296  findConstructionContexts(
3297  ConstructionContextLayer::create(cfg->getBumpVectorContext(), MTE),
3298  MTE->getTemporary());
3299 
3300  return VisitStmt(MTE, asc);
3301 }
3302 
3303 CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) {
3304  if (asc.alwaysAdd(*this, M)) {
3305  autoCreateBlock();
3306  appendStmt(Block, M);
3307  }
3308  return Visit(M->getBase());
3309 }
3310 
3311 CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) {
3312  // Objective-C fast enumeration 'for' statements:
3313  // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC
3314  //
3315  // for ( Type newVariable in collection_expression ) { statements }
3316  //
3317  // becomes:
3318  //
3319  // prologue:
3320  // 1. collection_expression
3321  // T. jump to loop_entry
3322  // loop_entry:
3323  // 1. side-effects of element expression
3324  // 1. ObjCForCollectionStmt [performs binding to newVariable]
3325  // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil]
3326  // TB:
3327  // statements
3328  // T. jump to loop_entry
3329  // FB:
3330  // what comes after
3331  //
3332  // and
3333  //
3334  // Type existingItem;
3335  // for ( existingItem in expression ) { statements }
3336  //
3337  // becomes:
3338  //
3339  // the same with newVariable replaced with existingItem; the binding works
3340  // the same except that for one ObjCForCollectionStmt::getElement() returns
3341  // a DeclStmt and the other returns a DeclRefExpr.
3342 
3343  CFGBlock *LoopSuccessor = nullptr;
3344 
3345  if (Block) {
3346  if (badCFG)
3347  return nullptr;
3348  LoopSuccessor = Block;
3349  Block = nullptr;
3350  } else
3351  LoopSuccessor = Succ;
3352 
3353  // Build the condition blocks.
3354  CFGBlock *ExitConditionBlock = createBlock(false);
3355 
3356  // Set the terminator for the "exit" condition block.
3357  ExitConditionBlock->setTerminator(S);
3358 
3359  // The last statement in the block should be the ObjCForCollectionStmt, which
3360  // performs the actual binding to 'element' and determines if there are any
3361  // more items in the collection.
3362  appendStmt(ExitConditionBlock, S);
3363  Block = ExitConditionBlock;
3364 
3365  // Walk the 'element' expression to see if there are any side-effects. We
3366  // generate new blocks as necessary. We DON'T add the statement by default to
3367  // the CFG unless it contains control-flow.
3368  CFGBlock *EntryConditionBlock = Visit(S->getElement(),
3369  AddStmtChoice::NotAlwaysAdd);
3370  if (Block) {
3371  if (badCFG)
3372  return nullptr;
3373  Block = nullptr;
3374  }
3375 
3376  // The condition block is the implicit successor for the loop body as well as
3377  // any code above the loop.
3378  Succ = EntryConditionBlock;
3379 
3380  // Now create the true branch.
3381  {
3382  // Save the current values for Succ, continue and break targets.
3383  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3384  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3385  save_break(BreakJumpTarget);
3386 
3387  // Add an intermediate block between the BodyBlock and the
3388  // EntryConditionBlock to represent the "loop back" transition, for looping
3389  // back to the head of the loop.
3390  CFGBlock *LoopBackBlock = nullptr;
3391  Succ = LoopBackBlock = createBlock();
3392  LoopBackBlock->setLoopTarget(S);
3393 
3394  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3395  ContinueJumpTarget = JumpTarget(Succ, ScopePos);
3396 
3397  CFGBlock *BodyBlock = addStmt(S->getBody());
3398 
3399  if (!BodyBlock)
3400  BodyBlock = ContinueJumpTarget.block; // can happen for "for (X in Y) ;"
3401  else if (Block) {
3402  if (badCFG)
3403  return nullptr;
3404  }
3405 
3406  // This new body block is a successor to our "exit" condition block.
3407  addSuccessor(ExitConditionBlock, BodyBlock);
3408  }
3409 
3410  // Link up the condition block with the code that follows the loop.
3411  // (the false branch).
3412  addSuccessor(ExitConditionBlock, LoopSuccessor);
3413 
3414  // Now create a prologue block to contain the collection expression.
3415  Block = createBlock();
3416  return addStmt(S->getCollection());
3417 }
3418 
3419 CFGBlock *CFGBuilder::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) {
3420  // Inline the body.
3421  return addStmt(S->getSubStmt());
3422  // TODO: consider adding cleanups for the end of @autoreleasepool scope.
3423 }
3424 
3425 CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) {
3426  // FIXME: Add locking 'primitives' to CFG for @synchronized.
3427 
3428  // Inline the body.
3429  CFGBlock *SyncBlock = addStmt(S->getSynchBody());
3430 
3431  // The sync body starts its own basic block. This makes it a little easier
3432  // for diagnostic clients.
3433  if (SyncBlock) {
3434  if (badCFG)
3435  return nullptr;
3436 
3437  Block = nullptr;
3438  Succ = SyncBlock;
3439  }
3440 
3441  // Add the @synchronized to the CFG.
3442  autoCreateBlock();
3443  appendStmt(Block, S);
3444 
3445  // Inline the sync expression.
3446  return addStmt(S->getSynchExpr());
3447 }
3448 
3449 CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) {
3450  // FIXME
3451  return NYS();
3452 }
3453 
3454 CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) {
3455  autoCreateBlock();
3456 
3457  // Add the PseudoObject as the last thing.
3458  appendStmt(Block, E);
3459 
3460  CFGBlock *lastBlock = Block;
3461 
3462  // Before that, evaluate all of the semantics in order. In
3463  // CFG-land, that means appending them in reverse order.
3464  for (unsigned i = E->getNumSemanticExprs(); i != 0; ) {
3465  Expr *Semantic = E->getSemanticExpr(--i);
3466 
3467  // If the semantic is an opaque value, we're being asked to bind
3468  // it to its source expression.
3469  if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
3470  Semantic = OVE->getSourceExpr();
3471 
3472  if (CFGBlock *B = Visit(Semantic))
3473  lastBlock = B;
3474  }
3475 
3476  return lastBlock;
3477 }
3478 
3479 CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) {
3480  CFGBlock *LoopSuccessor = nullptr;
3481 
3482  // Save local scope position because in case of condition variable ScopePos
3483  // won't be restored when traversing AST.
3484  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3485 
3486  // Create local scope for possible condition variable.
3487  // Store scope position for continue statement.
3488  LocalScope::const_iterator LoopBeginScopePos = ScopePos;
3489  if (VarDecl *VD = W->getConditionVariable()) {
3490  addLocalScopeForVarDecl(VD);
3491  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3492  }
3493  addLoopExit(W);
3494 
3495  // "while" is a control-flow statement. Thus we stop processing the current
3496  // block.
3497  if (Block) {
3498  if (badCFG)
3499  return nullptr;
3500  LoopSuccessor = Block;
3501  Block = nullptr;
3502  } else {
3503  LoopSuccessor = Succ;
3504  }
3505 
3506  CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
3507 
3508  // Process the loop body.
3509  {
3510  assert(W->getBody());
3511 
3512  // Save the current values for Block, Succ, continue and break targets.
3513  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3514  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3515  save_break(BreakJumpTarget);
3516 
3517  // Create an empty block to represent the transition block for looping back
3518  // to the head of the loop.
3519  Succ = TransitionBlock = createBlock(false);
3520  TransitionBlock->setLoopTarget(W);
3521  ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos);
3522 
3523  // All breaks should go to the code following the loop.
3524  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3525 
3526  // Loop body should end with destructor of Condition variable (if any).
3527  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3528 
3529  // If body is not a compound statement create implicit scope
3530  // and add destructors.
3531  if (!isa<CompoundStmt>(W->getBody()))
3532  addLocalScopeAndDtors(W->getBody());
3533 
3534  // Create the body. The returned block is the entry to the loop body.
3535  BodyBlock = addStmt(W->getBody());
3536 
3537  if (!BodyBlock)
3538  BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;"
3539  else if (Block && badCFG)
3540  return nullptr;
3541  }
3542 
3543  // Because of short-circuit evaluation, the condition of the loop can span
3544  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3545  // evaluate the condition.
3546  CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
3547 
3548  do {
3549  Expr *C = W->getCond();
3550 
3551  // Specially handle logical operators, which have a slightly
3552  // more optimal CFG representation.
3553  if (BinaryOperator *Cond = dyn_cast<BinaryOperator>(C->IgnoreParens()))
3554  if (Cond->isLogicalOp()) {
3555  std::tie(EntryConditionBlock, ExitConditionBlock) =
3556  VisitLogicalOperator(Cond, W, BodyBlock, LoopSuccessor);
3557  break;
3558  }
3559 
3560  // The default case when not handling logical operators.
3561  ExitConditionBlock = createBlock(false);
3562  ExitConditionBlock->setTerminator(W);
3563 
3564  // Now add the actual condition to the condition block.
3565  // Because the condition itself may contain control-flow, new blocks may
3566  // be created. Thus we update "Succ" after adding the condition.
3567  Block = ExitConditionBlock;
3568  Block = EntryConditionBlock = addStmt(C);
3569 
3570  // If this block contains a condition variable, add both the condition
3571  // variable and initializer to the CFG.
3572  if (VarDecl *VD = W->getConditionVariable()) {
3573  if (Expr *Init = VD->getInit()) {
3574  autoCreateBlock();
3575  const DeclStmt *DS = W->getConditionVariableDeclStmt();
3576  assert(DS->isSingleDecl());
3577  findConstructionContexts(
3578  ConstructionContextLayer::create(cfg->getBumpVectorContext(),
3579  const_cast<DeclStmt *>(DS)),
3580  Init);
3581  appendStmt(Block, DS);
3582  EntryConditionBlock = addStmt(Init);
3583  assert(Block == EntryConditionBlock);
3584  maybeAddScopeBeginForVarDecl(EntryConditionBlock, VD, C);
3585  }
3586  }
3587 
3588  if (Block && badCFG)
3589  return nullptr;
3590 
3591  // See if this is a known constant.
3592  const TryResult& KnownVal = tryEvaluateBool(C);
3593 
3594  // Add the loop body entry as a successor to the condition.
3595  addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
3596  // Link up the condition block with the code that follows the loop. (the
3597  // false branch).
3598  addSuccessor(ExitConditionBlock,
3599  KnownVal.isTrue() ? nullptr : LoopSuccessor);
3600  } while(false);
3601 
3602  // Link up the loop-back block to the entry condition block.
3603  addSuccessor(TransitionBlock, EntryConditionBlock);
3604 
3605  // There can be no more statements in the condition block since we loop back
3606  // to this block. NULL out Block to force lazy creation of another block.
3607  Block = nullptr;
3608 
3609  // Return the condition block, which is the dominating block for the loop.
3610  Succ = EntryConditionBlock;
3611  return EntryConditionBlock;
3612 }
3613 
3614 CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) {
3615  // FIXME: For now we pretend that @catch and the code it contains does not
3616  // exit.
3617  return Block;
3618 }
3619 
3620 CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) {
3621  // FIXME: This isn't complete. We basically treat @throw like a return
3622  // statement.
3623 
3624  // If we were in the middle of a block we stop processing that block.
3625  if (badCFG)
3626  return nullptr;
3627 
3628  // Create the new block.
3629  Block = createBlock(false);
3630 
3631  // The Exit block is the only successor.
3632  addSuccessor(Block, &cfg->getExit());
3633 
3634  // Add the statement to the block. This may create new blocks if S contains
3635  // control-flow (short-circuit operations).
3636  return VisitStmt(S, AddStmtChoice::AlwaysAdd);
3637 }
3638 
3639 CFGBlock *CFGBuilder::VisitObjCMessageExpr(ObjCMessageExpr *ME,
3640  AddStmtChoice asc) {
3641  findConstructionContextsForArguments(ME);
3642 
3643  autoCreateBlock();
3644  appendObjCMessage(Block, ME);
3645 
3646  return VisitChildren(ME);
3647 }
3648 
3649 CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) {
3650  // If we were in the middle of a block we stop processing that block.
3651  if (badCFG)
3652  return nullptr;
3653 
3654  // Create the new block.
3655  Block = createBlock(false);
3656 
3657  if (TryTerminatedBlock)
3658  // The current try statement is the only successor.
3659  addSuccessor(Block, TryTerminatedBlock);
3660  else
3661  // otherwise the Exit block is the only successor.
3662  addSuccessor(Block, &cfg->getExit());
3663 
3664  // Add the statement to the block. This may create new blocks if S contains
3665  // control-flow (short-circuit operations).
3666  return VisitStmt(T, AddStmtChoice::AlwaysAdd);
3667 }
3668 
3669 CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) {
3670  CFGBlock *LoopSuccessor = nullptr;
3671 
3672  addLoopExit(D);
3673 
3674  // "do...while" is a control-flow statement. Thus we stop processing the
3675  // current block.
3676  if (Block) {
3677  if (badCFG)
3678  return nullptr;
3679  LoopSuccessor = Block;
3680  } else
3681  LoopSuccessor = Succ;
3682 
3683  // Because of short-circuit evaluation, the condition of the loop can span
3684  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3685  // evaluate the condition.
3686  CFGBlock *ExitConditionBlock = createBlock(false);
3687  CFGBlock *EntryConditionBlock = ExitConditionBlock;
3688 
3689  // Set the terminator for the "exit" condition block.
3690  ExitConditionBlock->setTerminator(D);
3691 
3692  // Now add the actual condition to the condition block. Because the condition
3693  // itself may contain control-flow, new blocks may be created.
3694  if (Stmt *C = D->getCond()) {
3695  Block = ExitConditionBlock;
3696  EntryConditionBlock = addStmt(C);
3697  if (Block) {
3698  if (badCFG)
3699  return nullptr;
3700  }
3701  }
3702 
3703  // The condition block is the implicit successor for the loop body.
3704  Succ = EntryConditionBlock;
3705 
3706  // See if this is a known constant.
3707  const TryResult &KnownVal = tryEvaluateBool(D->getCond());
3708 
3709  // Process the loop body.
3710  CFGBlock *BodyBlock = nullptr;
3711  {
3712  assert(D->getBody());
3713 
3714  // Save the current values for Block, Succ, and continue and break targets
3715  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3716  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3717  save_break(BreakJumpTarget);
3718 
3719  // All continues within this loop should go to the condition block
3720  ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos);
3721 
3722  // All breaks should go to the code following the loop.
3723  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3724 
3725  // NULL out Block to force lazy instantiation of blocks for the body.
3726  Block = nullptr;
3727 
3728  // If body is not a compound statement create implicit scope
3729  // and add destructors.
3730  if (!isa<CompoundStmt>(D->getBody()))
3731  addLocalScopeAndDtors(D->getBody());
3732 
3733  // Create the body. The returned block is the entry to the loop body.
3734  BodyBlock = addStmt(D->getBody());
3735 
3736  if (!BodyBlock)
3737  BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)"
3738  else if (Block) {
3739  if (badCFG)
3740  return nullptr;
3741  }
3742 
3743  // Add an intermediate block between the BodyBlock and the
3744  // ExitConditionBlock to represent the "loop back" transition. Create an
3745  // empty block to represent the transition block for looping back to the
3746  // head of the loop.
3747  // FIXME: Can we do this more efficiently without adding another block?
3748  Block = nullptr;
3749  Succ = BodyBlock;
3750  CFGBlock *LoopBackBlock = createBlock();
3751  LoopBackBlock->setLoopTarget(D);
3752 
3753  if (!KnownVal.isFalse())
3754  // Add the loop body entry as a successor to the condition.
3755  addSuccessor(ExitConditionBlock, LoopBackBlock);
3756  else
3757  addSuccessor(ExitConditionBlock, nullptr);
3758  }
3759 
3760  // Link up the condition block with the code that follows the loop.
3761  // (the false branch).
3762  addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
3763 
3764  // There can be no more statements in the body block(s) since we loop back to
3765  // the body. NULL out Block to force lazy creation of another block.
3766  Block = nullptr;
3767 
3768  // Return the loop body, which is the dominating block for the loop.
3769  Succ = BodyBlock;
3770  return BodyBlock;
3771 }
3772 
3773 CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) {
3774  // "continue" is a control-flow statement. Thus we stop processing the
3775  // current block.
3776  if (badCFG)
3777  return nullptr;
3778 
3779  // Now create a new block that ends with the continue statement.
3780  Block = createBlock(false);
3781  Block->setTerminator(C);
3782 
3783  // If there is no target for the continue, then we are looking at an
3784  // incomplete AST. This means the CFG cannot be constructed.
3785  if (ContinueJumpTarget.block) {
3786  addAutomaticObjHandling(ScopePos, ContinueJumpTarget.scopePosition, C);
3787  addSuccessor(Block, ContinueJumpTarget.block);
3788  } else
3789  badCFG = true;
3790 
3791  return Block;
3792 }
3793 
3794 CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
3795  AddStmtChoice asc) {
3796  if (asc.alwaysAdd(*this, E)) {
3797  autoCreateBlock();
3798  appendStmt(Block, E);
3799  }
3800 
3801  // VLA types have expressions that must be evaluated.
3802  CFGBlock *lastBlock = Block;
3803 
3804  if (E->isArgumentType()) {
3805  for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr());
3806  VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr()))
3807  lastBlock = addStmt(VA->getSizeExpr());
3808  }
3809  return lastBlock;
3810 }
3811 
3812 /// VisitStmtExpr - Utility method to handle (nested) statement
3813 /// expressions (a GCC extension).
3814 CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) {
3815  if (asc.alwaysAdd(*this, SE)) {
3816  autoCreateBlock();
3817  appendStmt(Block, SE);
3818  }
3819  return VisitCompoundStmt(SE->getSubStmt());
3820 }
3821 
3822 CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) {
3823  // "switch" is a control-flow statement. Thus we stop processing the current
3824  // block.
3825  CFGBlock *SwitchSuccessor = nullptr;
3826 
3827  // Save local scope position because in case of condition variable ScopePos
3828  // won't be restored when traversing AST.
3829  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3830 
3831  // Create local scope for C++17 switch init-stmt if one exists.
3832  if (Stmt *Init = Terminator->getInit())
3833  addLocalScopeForStmt(Init);
3834 
3835  // Create local scope for possible condition variable.
3836  // Store scope position. Add implicit destructor.
3837  if (VarDecl *VD = Terminator->getConditionVariable())
3838  addLocalScopeForVarDecl(VD);
3839 
3840  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), Terminator);
3841 
3842  if (Block) {
3843  if (badCFG)
3844  return nullptr;
3845  SwitchSuccessor = Block;
3846  } else SwitchSuccessor = Succ;
3847 
3848  // Save the current "switch" context.
3849  SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock),
3850  save_default(DefaultCaseBlock);
3851  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3852 
3853  // Set the "default" case to be the block after the switch statement. If the
3854  // switch statement contains a "default:", this value will be overwritten with
3855  // the block for that code.
3856  DefaultCaseBlock = SwitchSuccessor;
3857 
3858  // Create a new block that will contain the switch statement.
3859  SwitchTerminatedBlock = createBlock(false);
3860 
3861  // Now process the switch body. The code after the switch is the implicit
3862  // successor.
3863  Succ = SwitchSuccessor;
3864  BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos);
3865 
3866  // When visiting the body, the case statements should automatically get linked
3867  // up to the switch. We also don't keep a pointer to the body, since all
3868  // control-flow from the switch goes to case/default statements.
3869  assert(Terminator->getBody() && "switch must contain a non-NULL body");
3870  Block = nullptr;
3871 
3872  // For pruning unreachable case statements, save the current state
3873  // for tracking the condition value.
3874  SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered,
3875  false);
3876 
3877  // Determine if the switch condition can be explicitly evaluated.
3878  assert(Terminator->getCond() && "switch condition must be non-NULL");
3879  Expr::EvalResult result;
3880  bool b = tryEvaluate(Terminator->getCond(), result);
3881  SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond,
3882  b ? &result : nullptr);
3883 
3884  // If body is not a compound statement create implicit scope
3885  // and add destructors.
3886  if (!isa<CompoundStmt>(Terminator->getBody()))
3887  addLocalScopeAndDtors(Terminator->getBody());
3888 
3889  addStmt(Terminator->getBody());
3890  if (Block) {
3891  if (badCFG)
3892  return nullptr;
3893  }
3894 
3895  // If we have no "default:" case, the default transition is to the code
3896  // following the switch body. Moreover, take into account if all the
3897  // cases of a switch are covered (e.g., switching on an enum value).
3898  //
3899  // Note: We add a successor to a switch that is considered covered yet has no
3900  // case statements if the enumeration has no enumerators.
3901  bool SwitchAlwaysHasSuccessor = false;
3902  SwitchAlwaysHasSuccessor |= switchExclusivelyCovered;
3903  SwitchAlwaysHasSuccessor |= Terminator->isAllEnumCasesCovered() &&
3904  Terminator->getSwitchCaseList();
3905  addSuccessor(SwitchTerminatedBlock, DefaultCaseBlock,
3906  !SwitchAlwaysHasSuccessor);
3907 
3908  // Add the terminator and condition in the switch block.
3909  SwitchTerminatedBlock->setTerminator(Terminator);
3910  Block = SwitchTerminatedBlock;
3911  CFGBlock *LastBlock = addStmt(Terminator->getCond());
3912 
3913  // If the SwitchStmt contains a condition variable, add both the
3914  // SwitchStmt and the condition variable initialization to the CFG.
3915  if (VarDecl *VD = Terminator->getConditionVariable()) {
3916  if (Expr *Init = VD->getInit()) {
3917  autoCreateBlock();
3918  appendStmt(Block, Terminator->getConditionVariableDeclStmt());
3919  LastBlock = addStmt(Init);
3920  maybeAddScopeBeginForVarDecl(LastBlock, VD, Init);
3921  }
3922  }
3923 
3924  // Finally, if the SwitchStmt contains a C++17 init-stmt, add it to the CFG.
3925  if (Stmt *Init = Terminator->getInit()) {
3926  autoCreateBlock();
3927  LastBlock = addStmt(Init);
3928  }
3929 
3930  return LastBlock;
3931 }
3932 
3933 static bool shouldAddCase(bool &switchExclusivelyCovered,
3934  const Expr::EvalResult *switchCond,
3935  const CaseStmt *CS,
3936  ASTContext &Ctx) {
3937  if (!switchCond)
3938  return true;
3939 
3940  bool addCase = false;
3941 
3942  if (!switchExclusivelyCovered) {
3943  if (switchCond->Val.isInt()) {
3944  // Evaluate the LHS of the case value.
3945  const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx);
3946  const llvm::APSInt &condInt = switchCond->Val.getInt();
3947 
3948  if (condInt == lhsInt) {
3949  addCase = true;
3950  switchExclusivelyCovered = true;
3951  }
3952  else if (condInt > lhsInt) {
3953  if (const Expr *RHS = CS->getRHS()) {
3954  // Evaluate the RHS of the case value.
3955  const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx);
3956  if (V2 >= condInt) {
3957  addCase = true;
3958  switchExclusivelyCovered = true;
3959  }
3960  }
3961  }
3962  }
3963  else
3964  addCase = true;
3965  }
3966  return addCase;
3967 }
3968 
3969 CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) {
3970  // CaseStmts are essentially labels, so they are the first statement in a
3971  // block.
3972  CFGBlock *TopBlock = nullptr, *LastBlock = nullptr;
3973 
3974  if (Stmt *Sub = CS->getSubStmt()) {
3975  // For deeply nested chains of CaseStmts, instead of doing a recursion
3976  // (which can blow out the stack), manually unroll and create blocks
3977  // along the way.
3978  while (isa<CaseStmt>(Sub)) {
3979  CFGBlock *currentBlock = createBlock(false);
3980  currentBlock->setLabel(CS);
3981 
3982  if (TopBlock)
3983  addSuccessor(LastBlock, currentBlock);
3984  else
3985  TopBlock = currentBlock;
3986 
3987  addSuccessor(SwitchTerminatedBlock,
3988  shouldAddCase(switchExclusivelyCovered, switchCond,
3989  CS, *Context)
3990  ? currentBlock : nullptr);
3991 
3992  LastBlock = currentBlock;
3993  CS = cast<CaseStmt>(Sub);
3994  Sub = CS->getSubStmt();
3995  }
3996 
3997  addStmt(Sub);
3998  }
3999 
4000  CFGBlock *CaseBlock = Block;
4001  if (!CaseBlock)
4002  CaseBlock = createBlock();
4003 
4004  // Cases statements partition blocks, so this is the top of the basic block we
4005  // were processing (the "case XXX:" is the label).
4006  CaseBlock->setLabel(CS);
4007 
4008  if (badCFG)
4009  return nullptr;
4010 
4011  // Add this block to the list of successors for the block with the switch
4012  // statement.
4013  assert(SwitchTerminatedBlock);
4014  addSuccessor(SwitchTerminatedBlock, CaseBlock,
4015  shouldAddCase(switchExclusivelyCovered, switchCond,
4016  CS, *Context));
4017 
4018  // We set Block to NULL to allow lazy creation of a new block (if necessary)
4019  Block = nullptr;
4020 
4021  if (TopBlock) {
4022  addSuccessor(LastBlock, CaseBlock);
4023  Succ = TopBlock;
4024  } else {
4025  // This block is now the implicit successor of other blocks.
4026  Succ = CaseBlock;
4027  }
4028 
4029  return Succ;
4030 }
4031 
4032 CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) {
4033  if (Terminator->getSubStmt())
4034  addStmt(Terminator->getSubStmt());
4035 
4036  DefaultCaseBlock = Block;
4037 
4038  if (!DefaultCaseBlock)
4039  DefaultCaseBlock = createBlock();
4040 
4041  // Default statements partition blocks, so this is the top of the basic block
4042  // we were processing (the "default:" is the label).
4043  DefaultCaseBlock->setLabel(Terminator);
4044 
4045  if (badCFG)
4046  return nullptr;
4047 
4048  // Unlike case statements, we don't add the default block to the successors
4049  // for the switch statement immediately. This is done when we finish
4050  // processing the switch statement. This allows for the default case
4051  // (including a fall-through to the code after the switch statement) to always
4052  // be the last successor of a switch-terminated block.
4053 
4054  // We set Block to NULL to allow lazy creation of a new block (if necessary)
4055  Block = nullptr;
4056 
4057  // This block is now the implicit successor of other blocks.
4058  Succ = DefaultCaseBlock;
4059 
4060  return DefaultCaseBlock;
4061 }
4062 
4063 CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) {
4064  // "try"/"catch" is a control-flow statement. Thus we stop processing the
4065  // current block.
4066  CFGBlock *TrySuccessor = nullptr;
4067 
4068  if (Block) {
4069  if (badCFG)
4070  return nullptr;
4071  TrySuccessor = Block;
4072  } else TrySuccessor = Succ;
4073 
4074  CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock;
4075 
4076  // Create a new block that will contain the try statement.
4077  CFGBlock *NewTryTerminatedBlock = createBlock(false);
4078  // Add the terminator in the try block.
4079  NewTryTerminatedBlock->setTerminator(Terminator);
4080 
4081  bool HasCatchAll = false;
4082  for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) {
4083  // The code after the try is the implicit successor.
4084  Succ = TrySuccessor;
4085  CXXCatchStmt *CS = Terminator->getHandler(h);
4086  if (CS->getExceptionDecl() == nullptr) {
4087  HasCatchAll = true;
4088  }
4089  Block = nullptr;
4090  CFGBlock *CatchBlock = VisitCXXCatchStmt(CS);
4091  if (!CatchBlock)
4092  return nullptr;
4093  // Add this block to the list of successors for the block with the try
4094  // statement.
4095  addSuccessor(NewTryTerminatedBlock, CatchBlock);
4096  }
4097  if (!HasCatchAll) {
4098  if (PrevTryTerminatedBlock)
4099  addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock);
4100  else
4101  addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
4102  }
4103 
4104  // The code after the try is the implicit successor.
4105  Succ = TrySuccessor;
4106 
4107  // Save the current "try" context.
4108  SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock);
4109  cfg->addTryDispatchBlock(TryTerminatedBlock);
4110 
4111  assert(Terminator->getTryBlock() && "try must contain a non-NULL body");
4112  Block = nullptr;
4113  return addStmt(Terminator->getTryBlock());
4114 }
4115 
4116 CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) {
4117  // CXXCatchStmt are treated like labels, so they are the first statement in a
4118  // block.
4119 
4120  // Save local scope position because in case of exception variable ScopePos
4121  // won't be restored when traversing AST.
4122  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
4123 
4124  // Create local scope for possible exception variable.
4125  // Store scope position. Add implicit destructor.
4126  if (VarDecl *VD = CS->getExceptionDecl()) {
4127  LocalScope::const_iterator BeginScopePos = ScopePos;
4128  addLocalScopeForVarDecl(VD);
4129  addAutomaticObjHandling(ScopePos, BeginScopePos, CS);
4130  }
4131 
4132  if (CS->getHandlerBlock())
4133  addStmt(CS->getHandlerBlock());
4134 
4135  CFGBlock *CatchBlock = Block;
4136  if (!CatchBlock)
4137  CatchBlock = createBlock();
4138 
4139  // CXXCatchStmt is more than just a label. They have semantic meaning
4140  // as well, as they implicitly "initialize" the catch variable. Add
4141  // it to the CFG as a CFGElement so that the control-flow of these
4142  // semantics gets captured.
4143  appendStmt(CatchBlock, CS);
4144 
4145  // Also add the CXXCatchStmt as a label, to mirror handling of regular
4146  // labels.
4147  CatchBlock->setLabel(CS);
4148 
4149  // Bail out if the CFG is bad.
4150  if (badCFG)
4151  return nullptr;
4152 
4153  // We set Block to NULL to allow lazy creation of a new block (if necessary)
4154  Block = nullptr;
4155 
4156  return CatchBlock;
4157 }
4158 
4159 CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) {
4160  // C++0x for-range statements are specified as [stmt.ranged]:
4161  //
4162  // {
4163  // auto && __range = range-init;
4164  // for ( auto __begin = begin-expr,
4165  // __end = end-expr;
4166  // __begin != __end;
4167  // ++__begin ) {
4168  // for-range-declaration = *__begin;
4169  // statement
4170  // }
4171  // }
4172 
4173  // Save local scope position before the addition of the implicit variables.
4174  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
4175 
4176  // Create local scopes and destructors for range, begin and end variables.
4177  if (Stmt *Range = S->getRangeStmt())
4178  addLocalScopeForStmt(Range);
4179  if (Stmt *Begin = S->getBeginStmt())
4180  addLocalScopeForStmt(Begin);
4181  if (Stmt *End = S->getEndStmt())
4182  addLocalScopeForStmt(End);
4183  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), S);
4184 
4185  LocalScope::const_iterator ContinueScopePos = ScopePos;
4186 
4187  // "for" is a control-flow statement. Thus we stop processing the current
4188  // block.
4189  CFGBlock *LoopSuccessor = nullptr;
4190  if (Block) {
4191  if (badCFG)
4192  return nullptr;
4193  LoopSuccessor = Block;
4194  } else
4195  LoopSuccessor = Succ;
4196 
4197  // Save the current value for the break targets.
4198  // All breaks should go to the code following the loop.
4199  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
4200  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
4201 
4202  // The block for the __begin != __end expression.
4203  CFGBlock *ConditionBlock = createBlock(false);
4204  ConditionBlock->setTerminator(S);
4205 
4206  // Now add the actual condition to the condition block.
4207  if (Expr *C = S->getCond()) {
4208  Block = ConditionBlock;
4209  CFGBlock *BeginConditionBlock = addStmt(C);
4210  if (badCFG)
4211  return nullptr;
4212  assert(BeginConditionBlock == ConditionBlock &&
4213  "condition block in for-range was unexpectedly complex");
4214  (void)BeginConditionBlock;
4215  }
4216 
4217  // The condition block is the implicit successor for the loop body as well as
4218  // any code above the loop.
4219  Succ = ConditionBlock;
4220 
4221  // See if this is a known constant.
4222  TryResult KnownVal(true);
4223 
4224  if (S->getCond())
4225  KnownVal = tryEvaluateBool(S->getCond());
4226 
4227  // Now create the loop body.
4228  {
4229  assert(S->getBody());
4230 
4231  // Save the current values for Block, Succ, and continue targets.
4232  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
4233  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
4234 
4235  // Generate increment code in its own basic block. This is the target of
4236  // continue statements.
4237  Block = nullptr;
4238  Succ = addStmt(S->getInc());
4239  if (badCFG)
4240  return nullptr;
4241  ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
4242 
4243  // The starting block for the loop increment is the block that should
4244  // represent the 'loop target' for looping back to the start of the loop.
4245  ContinueJumpTarget.block->setLoopTarget(S);
4246 
4247  // Finish up the increment block and prepare to start the loop body.
4248  assert(Block);
4249  if (badCFG)
4250  return nullptr;
4251  Block = nullptr;
4252 
4253  // Add implicit scope and dtors for loop variable.
4254  addLocalScopeAndDtors(S->getLoopVarStmt());
4255 
4256  // Populate a new block to contain the loop body and loop variable.
4257  addStmt(S->getBody());
4258  if (badCFG)
4259  return nullptr;
4260  CFGBlock *LoopVarStmtBlock = addStmt(S->getLoopVarStmt());
4261  if (badCFG)
4262  return nullptr;
4263 
4264  // This new body block is a successor to our condition block.
4265  addSuccessor(ConditionBlock,
4266  KnownVal.isFalse() ? nullptr : LoopVarStmtBlock);
4267  }
4268 
4269  // Link up the condition block with the code that follows the loop (the
4270  // false branch).
4271  addSuccessor(ConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
4272 
4273  // Add the initialization statements.
4274  Block = createBlock();
4275  addStmt(S->getBeginStmt());
4276  addStmt(S->getEndStmt());
4277  CFGBlock *Head = addStmt(S->getRangeStmt());
4278  if (S->getInit())
4279  Head = addStmt(S->getInit());
4280  return Head;
4281 }
4282 
4283 CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E,
4284  AddStmtChoice asc) {
4285  if (BuildOpts.AddTemporaryDtors) {
4286  // If adding implicit destructors visit the full expression for adding
4287  // destructors of temporaries.
4288  TempDtorContext Context;
4289  VisitForTemporaryDtors(E->getSubExpr(), false, Context);
4290 
4291  // Full expression has to be added as CFGStmt so it will be sequenced
4292  // before destructors of it's temporaries.
4293  asc = asc.withAlwaysAdd(true);
4294  }
4295  return Visit(E->getSubExpr(), asc);
4296 }
4297 
4298 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
4299  AddStmtChoice asc) {
4300  if (asc.alwaysAdd(*this, E)) {
4301  autoCreateBlock();
4302  appendStmt(Block, E);
4303 
4304  findConstructionContexts(
4305  ConstructionContextLayer::create(cfg->getBumpVectorContext(), E),
4306  E->getSubExpr());
4307 
4308  // We do not want to propagate the AlwaysAdd property.
4309  asc = asc.withAlwaysAdd(false);
4310  }
4311  return Visit(E->getSubExpr(), asc);
4312 }
4313 
4314 CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C,
4315  AddStmtChoice asc) {
4316  // If the constructor takes objects as arguments by value, we need to properly
4317  // construct these objects. Construction contexts we find here aren't for the
4318  // constructor C, they're for its arguments only.
4319  findConstructionContextsForArguments(C);
4320 
4321  autoCreateBlock();
4322  appendConstructor(Block, C);
4323 
4324  return VisitChildren(C);
4325 }
4326 
4327 CFGBlock *CFGBuilder::VisitCXXNewExpr(CXXNewExpr *NE,
4328  AddStmtChoice asc) {
4329  autoCreateBlock();
4330  appendStmt(Block, NE);
4331 
4332  findConstructionContexts(
4333  ConstructionContextLayer::create(cfg->getBumpVectorContext(), NE),
4334  const_cast<CXXConstructExpr *>(NE->getConstructExpr()));
4335 
4336  if (NE->getInitializer())
4337  Block = Visit(NE->getInitializer());
4338 
4339  if (BuildOpts.AddCXXNewAllocator)
4340  appendNewAllocator(Block, NE);
4341 
4342  if (NE->isArray() && *NE->getArraySize())
4343  Block = Visit(*NE->getArraySize());
4344 
4346  E = NE->placement_arg_end(); I != E; ++I)
4347  Block = Visit(*I);
4348 
4349  return Block;
4350 }
4351 
4352 CFGBlock *CFGBuilder::VisitCXXDeleteExpr(CXXDeleteExpr *DE,
4353  AddStmtChoice asc) {
4354  autoCreateBlock();
4355  appendStmt(Block, DE);
4356  QualType DTy = DE->getDestroyedType();
4357  if (!DTy.isNull()) {
4358  DTy = DTy.getNonReferenceType();
4359  CXXRecordDecl *RD = Context->getBaseElementType(DTy)->getAsCXXRecordDecl();
4360  if (RD) {
4361  if (RD->isCompleteDefinition() && !RD->hasTrivialDestructor())
4362  appendDeleteDtor(Block, RD, DE);
4363  }
4364  }
4365 
4366  return VisitChildren(DE);
4367 }
4368 
4369 CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
4370  AddStmtChoice asc) {
4371  if (asc.alwaysAdd(*this, E)) {
4372  autoCreateBlock();
4373  appendStmt(Block, E);
4374  // We do not want to propagate the AlwaysAdd property.
4375  asc = asc.withAlwaysAdd(false);
4376  }
4377  return Visit(E->getSubExpr(), asc);
4378 }
4379 
4380 CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
4381  AddStmtChoice asc) {
4382  // If the constructor takes objects as arguments by value, we need to properly
4383  // construct these objects. Construction contexts we find here aren't for the
4384  // constructor C, they're for its arguments only.
4385  findConstructionContextsForArguments(C);
4386 
4387  autoCreateBlock();
4388  appendConstructor(Block, C);
4389  return VisitChildren(C);
4390 }
4391 
4392 CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E,
4393  AddStmtChoice asc) {
4394  if (asc.alwaysAdd(*this, E)) {
4395  autoCreateBlock();
4396  appendStmt(Block, E);
4397  }
4398  return Visit(E->getSubExpr(), AddStmtChoice());
4399 }
4400 
4401 CFGBlock *CFGBuilder::VisitConstantExpr(ConstantExpr *E, AddStmtChoice asc) {
4402  return Visit(E->getSubExpr(), AddStmtChoice());
4403 }
4404 
4405 CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) {
4406  // Lazily create the indirect-goto dispatch block if there isn't one already.
4407  CFGBlock *IBlock = cfg->getIndirectGotoBlock();
4408 
4409  if (!IBlock) {
4410  IBlock = createBlock(false);
4411  cfg->setIndirectGotoBlock(IBlock);
4412  }
4413 
4414  // IndirectGoto is a control-flow statement. Thus we stop processing the
4415  // current block and create a new one.
4416  if (badCFG)
4417  return nullptr;
4418 
4419  Block = createBlock(false);
4420  Block->setTerminator(I);
4421  addSuccessor(Block, IBlock);
4422  return addStmt(I->getTarget());
4423 }
4424 
4425 CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary,
4426  TempDtorContext &Context) {
4427  assert(BuildOpts.AddImplicitDtors && BuildOpts.AddTemporaryDtors);
4428 
4429 tryAgain:
4430  if (!E) {
4431  badCFG = true;
4432  return nullptr;
4433  }
4434  switch (E->getStmtClass()) {
4435  default:
4436  return VisitChildrenForTemporaryDtors(E, Context);
4437 
4438  case Stmt::BinaryOperatorClass:
4439  return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E),
4440  Context);
4441 
4442  case Stmt::CXXBindTemporaryExprClass:
4443  return VisitCXXBindTemporaryExprForTemporaryDtors(
4444  cast<CXXBindTemporaryExpr>(E), BindToTemporary, Context);
4445 
4446  case Stmt::BinaryConditionalOperatorClass:
4447  case Stmt::ConditionalOperatorClass:
4448  return VisitConditionalOperatorForTemporaryDtors(
4449  cast<AbstractConditionalOperator>(E), BindToTemporary, Context);
4450 
4451  case Stmt::ImplicitCastExprClass:
4452  // For implicit cast we want BindToTemporary to be passed further.
4453  E = cast<CastExpr>(E)->getSubExpr();
4454  goto tryAgain;
4455 
4456  case Stmt::CXXFunctionalCastExprClass:
4457  // For functional cast we want BindToTemporary to be passed further.
4458  E = cast<CXXFunctionalCastExpr>(E)->getSubExpr();
4459  goto tryAgain;
4460 
4461  case Stmt::ConstantExprClass:
4462  E = cast<ConstantExpr>(E)->getSubExpr();
4463  goto tryAgain;
4464 
4465  case Stmt::ParenExprClass:
4466  E = cast<ParenExpr>(E)->getSubExpr();
4467  goto tryAgain;
4468 
4469  case Stmt::MaterializeTemporaryExprClass: {
4470  const MaterializeTemporaryExpr* MTE = cast<MaterializeTemporaryExpr>(E);
4471  BindToTemporary = (MTE->getStorageDuration() != SD_FullExpression);
4472  SmallVector<const Expr *, 2> CommaLHSs;
4474  // Find the expression whose lifetime needs to be extended.
4475  E = const_cast<Expr *>(
4476  cast<MaterializeTemporaryExpr>(E)
4477  ->GetTemporaryExpr()
4478  ->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments));
4479  // Visit the skipped comma operator left-hand sides for other temporaries.
4480  for (const Expr *CommaLHS : CommaLHSs) {
4481  VisitForTemporaryDtors(const_cast<Expr *>(CommaLHS),
4482  /*BindToTemporary=*/false, Context);
4483  }
4484  goto tryAgain;
4485  }
4486 
4487  case Stmt::BlockExprClass:
4488  // Don't recurse into blocks; their subexpressions don't get evaluated
4489  // here.
4490  return Block;
4491 
4492  case Stmt::LambdaExprClass: {
4493  // For lambda expressions, only recurse into the capture initializers,
4494  // and not the body.
4495  auto *LE = cast<LambdaExpr>(E);
4496  CFGBlock *B = Block;
4497  for (Expr *Init : LE->capture_inits()) {
4498  if (Init) {
4499  if (CFGBlock *R = VisitForTemporaryDtors(
4500  Init, /*BindToTemporary=*/false, Context))
4501  B = R;
4502  }
4503  }
4504  return B;
4505  }
4506 
4507  case Stmt::CXXDefaultArgExprClass:
4508  E = cast<CXXDefaultArgExpr>(E)->getExpr();
4509  goto tryAgain;
4510 
4511  case Stmt::CXXDefaultInitExprClass:
4512  E = cast<CXXDefaultInitExpr>(E)->getExpr();
4513  goto tryAgain;
4514  }
4515 }
4516 
4517 CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E,
4518  TempDtorContext &Context) {
4519  if (isa<LambdaExpr>(E)) {
4520  // Do not visit the children of lambdas; they have their own CFGs.
4521  return Block;
4522  }
4523 
4524  // When visiting children for destructors we want to visit them in reverse
4525  // order that they will appear in the CFG. Because the CFG is built
4526  // bottom-up, this means we visit them in their natural order, which
4527  // reverses them in the CFG.
4528  CFGBlock *B = Block;
4529  for (Stmt *Child : E->children())
4530  if (Child)
4531  if (CFGBlock *R = VisitForTemporaryDtors(Child, false, Context))
4532  B = R;
4533 
4534  return B;
4535 }
4536 
4537 CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(
4538  BinaryOperator *E, TempDtorContext &Context) {
4539  if (E->isLogicalOp()) {
4540  VisitForTemporaryDtors(E->getLHS(), false, Context);
4541  TryResult RHSExecuted = tryEvaluateBool(E->getLHS());
4542  if (RHSExecuted.isKnown() && E->getOpcode() == BO_LOr)
4543  RHSExecuted.negate();
4544 
4545  // We do not know at CFG-construction time whether the right-hand-side was
4546  // executed, thus we add a branch node that depends on the temporary
4547  // constructor call.
4548  TempDtorContext RHSContext(
4549  bothKnownTrue(Context.KnownExecuted, RHSExecuted));
4550  VisitForTemporaryDtors(E->getRHS(), false, RHSContext);
4551  InsertTempDtorDecisionBlock(RHSContext);
4552 
4553  return Block;
4554  }
4555 
4556  if (E->isAssignmentOp()) {
4557  // For assignment operator (=) LHS expression is visited
4558  // before RHS expression. For destructors visit them in reverse order.
4559  CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
4560  CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
4561  return LHSBlock ? LHSBlock : RHSBlock;
4562  }
4563 
4564  // For any other binary operator RHS expression is visited before
4565  // LHS expression (order of children). For destructors visit them in reverse
4566  // order.
4567  CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
4568  CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
4569  return RHSBlock ? RHSBlock : LHSBlock;
4570 }
4571 
4572 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors(
4573  CXXBindTemporaryExpr *E, bool BindToTemporary, TempDtorContext &Context) {
4574  // First add destructors for temporaries in subexpression.
4575  CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr(), false, Context);
4576  if (!BindToTemporary) {
4577  // If lifetime of temporary is not prolonged (by assigning to constant
4578  // reference) add destructor for it.
4579 
4580  const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor();
4581 
4582  if (Dtor->getParent()->isAnyDestructorNoReturn()) {
4583  // If the destructor is marked as a no-return destructor, we need to
4584  // create a new block for the destructor which does not have as a
4585  // successor anything built thus far. Control won't flow out of this
4586  // block.
4587  if (B) Succ = B;
4588  Block = createNoReturnBlock();
4589  } else if (Context.needsTempDtorBranch()) {
4590  // If we need to introduce a branch, we add a new block that we will hook
4591  // up to a decision block later.
4592  if (B) Succ = B;
4593  Block = createBlock();
4594  } else {
4595  autoCreateBlock();
4596  }
4597  if (Context.needsTempDtorBranch()) {
4598  Context.setDecisionPoint(Succ, E);
4599  }
4600  appendTemporaryDtor(Block, E);
4601 
4602  B = Block;
4603  }
4604  return B;
4605 }
4606 
4607 void CFGBuilder::InsertTempDtorDecisionBlock(const TempDtorContext &Context,
4608  CFGBlock *FalseSucc) {
4609  if (!Context.TerminatorExpr) {
4610  // If no temporary was found, we do not need to insert a decision point.
4611  return;
4612  }
4613  assert(Context.TerminatorExpr);
4614  CFGBlock *Decision = createBlock(false);
4615  Decision->setTerminator(CFGTerminator(Context.TerminatorExpr, true));
4616  addSuccessor(Decision, Block, !Context.KnownExecuted.isFalse());
4617  addSuccessor(Decision, FalseSucc ? FalseSucc : Context.Succ,
4618  !Context.KnownExecuted.isTrue());
4619  Block = Decision;
4620 }
4621 
4622 CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors(
4623  AbstractConditionalOperator *E, bool BindToTemporary,
4624  TempDtorContext &Context) {
4625  VisitForTemporaryDtors(E->getCond(), false, Context);
4626  CFGBlock *ConditionBlock = Block;
4627  CFGBlock *ConditionSucc = Succ;
4628  TryResult ConditionVal = tryEvaluateBool(E->getCond());
4629  TryResult NegatedVal = ConditionVal;
4630  if (NegatedVal.isKnown()) NegatedVal.negate();
4631 
4632  TempDtorContext TrueContext(
4633  bothKnownTrue(Context.KnownExecuted, ConditionVal));
4634  VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary, TrueContext);
4635  CFGBlock *TrueBlock = Block;
4636 
4637  Block = ConditionBlock;
4638  Succ = ConditionSucc;
4639  TempDtorContext FalseContext(
4640  bothKnownTrue(Context.KnownExecuted, NegatedVal));
4641  VisitForTemporaryDtors(E->getFalseExpr(), BindToTemporary, FalseContext);
4642 
4643  if (TrueContext.TerminatorExpr && FalseContext.TerminatorExpr) {
4644  InsertTempDtorDecisionBlock(FalseContext, TrueBlock);
4645  } else if (TrueContext.TerminatorExpr) {
4646  Block = TrueBlock;
4647  InsertTempDtorDecisionBlock(TrueContext);
4648  } else {
4649  InsertTempDtorDecisionBlock(FalseContext);
4650  }
4651  return Block;
4652 }
4653 
4654 /// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has
4655 /// no successors or predecessors. If this is the first block created in the
4656 /// CFG, it is automatically set to be the Entry and Exit of the CFG.
4658  bool first_block = begin() == end();
4659 
4660  // Create the block.
4661  CFGBlock *Mem = getAllocator().Allocate<CFGBlock>();
4662  new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this);
4663  Blocks.push_back(Mem, BlkBVC);
4664 
4665  // If this is the first block, set it as the Entry and Exit.
4666  if (first_block)
4667  Entry = Exit = &back();
4668 
4669  // Return the block.
4670  return &back();
4671 }
4672 
4673 /// buildCFG - Constructs a CFG from an AST.
4674 std::unique_ptr<CFG> CFG::buildCFG(const Decl *D, Stmt *Statement,
4675  ASTContext *C, const BuildOptions &BO) {
4676  CFGBuilder Builder(C, BO);
4677  return Builder.buildCFG(D, Statement);
4678 }
4679 
4680 bool CFG::isLinear() const {
4681  // Quick path: if we only have the ENTRY block, the EXIT block, and some code
4682  // in between, then we have no room for control flow.
4683  if (size() <= 3)
4684  return true;
4685 
4686  // Traverse the CFG until we find a branch.
4687  // TODO: While this should still be very fast,
4688  // maybe we should cache the answer.
4689  llvm::SmallPtrSet<const CFGBlock *, 4> Visited;
4690  const CFGBlock *B = Entry;
4691  while (B != Exit) {
4692  auto IteratorAndFlag = Visited.insert(B);
4693  if (!IteratorAndFlag.second) {
4694  // We looped back to a block that we've already visited. Not linear.
4695  return false;
4696  }
4697 
4698  // Iterate over reachable successors.
4699  const CFGBlock *FirstReachableB = nullptr;
4700  for (const CFGBlock::AdjacentBlock &AB : B->succs()) {
4701  if (!AB.isReachable())
4702  continue;
4703 
4704  if (FirstReachableB == nullptr) {
4705  FirstReachableB = &*AB;
4706  } else {
4707  // We've encountered a branch. It's not a linear CFG.
4708  return false;
4709  }
4710  }
4711 
4712  if (!FirstReachableB) {
4713  // We reached a dead end. EXIT is unreachable. This is linear enough.
4714  return true;
4715  }
4716 
4717  // There's only one way to move forward. Proceed.
4718  B = FirstReachableB;
4719  }
4720 
4721  // We reached EXIT and found no branches.
4722  return true;
4723 }
4724 
4725 const CXXDestructorDecl *
4727  switch (getKind()) {
4730  case CFGElement::LoopExit:
4732  case CFGElement::Statement:
4736  case CFGElement::ScopeEnd:
4737  llvm_unreachable("getDestructorDecl should only be used with "
4738  "ImplicitDtors");
4740  const VarDecl *var = castAs<CFGAutomaticObjDtor>().getVarDecl();
4741  QualType ty = var->getType();
4742 
4743  // FIXME: See CFGBuilder::addLocalScopeForVarDecl.
4744  //
4745  // Lifetime-extending constructs are handled here. This works for a single
4746  // temporary in an initializer expression.
4747  if (ty->isReferenceType()) {
4748  if (const Expr *Init = var->getInit()) {
4749  ty = getReferenceInitTemporaryType(Init);
4750  }
4751  }
4752 
4753  while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) {
4754  ty = arrayType->getElementType();
4755  }
4756  const RecordType *recordType = ty->getAs<RecordType>();
4757  const CXXRecordDecl *classDecl =
4758  cast<CXXRecordDecl>(recordType->getDecl());
4759  return classDecl->getDestructor();
4760  }
4761  case CFGElement::DeleteDtor: {
4762  const CXXDeleteExpr *DE = castAs<CFGDeleteDtor>().getDeleteExpr();
4763  QualType DTy = DE->getDestroyedType();
4764  DTy = DTy.getNonReferenceType();
4765  const CXXRecordDecl *classDecl =
4766  astContext.getBaseElementType(DTy)->getAsCXXRecordDecl();
4767  return classDecl->getDestructor();
4768  }
4770  const CXXBindTemporaryExpr *bindExpr =
4771  castAs<CFGTemporaryDtor>().getBindTemporaryExpr();
4772  const CXXTemporary *temp = bindExpr->getTemporary();
4773  return temp->getDestructor();
4774  }
4775  case CFGElement::BaseDtor:
4777  // Not yet supported.
4778  return nullptr;
4779  }
4780  llvm_unreachable("getKind() returned bogus value");
4781 }
4782 
4783 bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const {
4784  if (const CXXDestructorDecl *DD = getDestructorDecl(astContext))
4785  return DD->isNoReturn();
4786  return false;
4787 }
4788 
4789 //===----------------------------------------------------------------------===//
4790 // CFGBlock operations.
4791 //===----------------------------------------------------------------------===//
4792 
4794  : ReachableBlock(IsReachable ? B : nullptr),
4795  UnreachableBlock(!IsReachable ? B : nullptr,
4796  B && IsReachable ? AB_Normal : AB_Unreachable) {}
4797 
4799  : ReachableBlock(B),
4800  UnreachableBlock(B == AlternateBlock ? nullptr : AlternateBlock,
4801  B == AlternateBlock ? AB_Alternate : AB_Normal) {}
4802 
4804  BumpVectorContext &C) {
4805  if (CFGBlock *B = Succ.getReachableBlock())
4806  B->Preds.push_back(AdjacentBlock(this, Succ.isReachable()), C);
4807 
4808  if (CFGBlock *UnreachableB = Succ.getPossiblyUnreachableBlock())
4809  UnreachableB->Preds.push_back(AdjacentBlock(this, false), C);
4810 
4811  Succs.push_back(Succ, C);
4812 }
4813 
4815  const CFGBlock *From, const CFGBlock *To) {
4816  if (F.IgnoreNullPredecessors && !From)
4817  return true;
4818 
4819  if (To && From && F.IgnoreDefaultsWithCoveredEnums) {
4820  // If the 'To' has no label or is labeled but the label isn't a
4821  // CaseStmt then filter this edge.
4822  if (const SwitchStmt *S =
4823  dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) {
4824  if (S->isAllEnumCasesCovered()) {
4825  const Stmt *L = To->getLabel();
4826  if (!L || !isa<CaseStmt>(L))
4827  return true;
4828  }
4829  }
4830  }
4831 
4832  return false;
4833 }
4834 
4835 //===----------------------------------------------------------------------===//
4836 // CFG pretty printing
4837 //===----------------------------------------------------------------------===//
4838 
4839 namespace {
4840 
4841 class StmtPrinterHelper : public PrinterHelper {
4842  using StmtMapTy = llvm::DenseMap<const Stmt *, std::pair<unsigned, unsigned>>;
4843  using DeclMapTy = llvm::DenseMap<const Decl *, std::pair<unsigned, unsigned>>;
4844 
4845  StmtMapTy StmtMap;
4846  DeclMapTy DeclMap;
4847  signed currentBlock = 0;
4848  unsigned currStmt = 0;
4849  const LangOptions &LangOpts;
4850 
4851 public:
4852  StmtPrinterHelper(const CFG* cfg, const LangOptions &LO)
4853  : LangOpts(LO) {
4854  for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) {
4855  unsigned j = 1;
4856  for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ;
4857  BI != BEnd; ++BI, ++j ) {
4858  if (Optional<CFGStmt> SE = BI->getAs<CFGStmt>()) {
4859  const Stmt *stmt= SE->getStmt();
4860  std::pair<unsigned, unsigned> P((*I)->getBlockID(), j);
4861  StmtMap[stmt] = P;
4862 
4863  switch (stmt->getStmtClass()) {
4864  case Stmt::DeclStmtClass:
4865  DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P;
4866  break;
4867  case Stmt::IfStmtClass: {
4868  const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable();
4869  if (var)
4870  DeclMap[var] = P;
4871  break;
4872  }
4873  case Stmt::ForStmtClass: {
4874  const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable();
4875  if (var)
4876  DeclMap[var] = P;
4877  break;
4878  }
4879  case Stmt::WhileStmtClass: {
4880  const VarDecl *var =
4881  cast<WhileStmt>(stmt)->getConditionVariable();
4882  if (var)
4883  DeclMap[var] = P;
4884  break;
4885  }
4886  case Stmt::SwitchStmtClass: {
4887  const VarDecl *var =
4888  cast<SwitchStmt>(stmt)->getConditionVariable();
4889  if (var)
4890  DeclMap[var] = P;
4891  break;
4892  }
4893  case Stmt::CXXCatchStmtClass: {
4894  const VarDecl *var =
4895  cast<CXXCatchStmt>(stmt)->getExceptionDecl();
4896  if (var)
4897  DeclMap[var] = P;
4898  break;
4899  }
4900  default:
4901  break;
4902  }
4903  }
4904  }
4905  }
4906  }
4907 
4908  ~StmtPrinterHelper() override = default;
4909 
4910  const LangOptions &getLangOpts() const { return LangOpts; }
4911  void setBlockID(signed i) { currentBlock = i; }
4912  void setStmtID(unsigned i) { currStmt = i; }
4913 
4914  bool handledStmt(Stmt *S, raw_ostream &OS) override {
4915  StmtMapTy::iterator I = StmtMap.find(S);
4916 
4917  if (I == StmtMap.end())
4918  return false;
4919 
4920  if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
4921  && I->second.second == currStmt) {
4922  return false;
4923  }
4924 
4925  OS << "[B" << I->second.first << "." << I->second.second << "]";
4926  return true;
4927  }
4928 
4929  bool handleDecl(const Decl *D, raw_ostream &OS) {
4930  DeclMapTy::iterator I = DeclMap.find(D);
4931 
4932  if (I == DeclMap.end())
4933  return false;
4934 
4935  if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
4936  && I->second.second == currStmt) {
4937  return false;
4938  }
4939 
4940  OS << "[B" << I->second.first << "." << I->second.second << "]";
4941  return true;
4942  }
4943 };
4944 
4945 class CFGBlockTerminatorPrint
4946  : public StmtVisitor<CFGBlockTerminatorPrint,void> {
4947  raw_ostream &OS;
4948  StmtPrinterHelper* Helper;
4949  PrintingPolicy Policy;
4950 
4951 public:
4952  CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper,
4953  const PrintingPolicy &Policy)
4954  : OS(os), Helper(helper), Policy(Policy) {
4955  this->Policy.IncludeNewlines = false;
4956  }
4957 
4958  void VisitIfStmt(IfStmt *I) {
4959  OS << "if ";
4960  if (Stmt *C = I->getCond())
4961  C->printPretty(OS, Helper, Policy);
4962  }
4963 
4964  // Default case.
4965  void VisitStmt(Stmt *Terminator) {
4966  Terminator->printPretty(OS, Helper, Policy);
4967  }
4968 
4969  void VisitDeclStmt(DeclStmt *DS) {
4970  VarDecl *VD = cast<VarDecl>(DS->getSingleDecl());
4971  OS << "static init " << VD->getName();
4972  }
4973 
4974  void VisitForStmt(ForStmt *F) {
4975  OS << "for (" ;
4976  if (F->getInit())
4977  OS << "...";
4978  OS << "; ";
4979  if (Stmt *C = F->getCond())
4980  C->printPretty(OS, Helper, Policy);
4981  OS << "; ";
4982  if (F->getInc())
4983  OS << "...";
4984  OS << ")";
4985  }
4986 
4987  void VisitWhileStmt(WhileStmt *W) {
4988  OS << "while " ;
4989  if (Stmt *C = W->getCond())
4990  C->printPretty(OS, Helper, Policy);
4991  }
4992 
4993  void VisitDoStmt(DoStmt *D) {
4994  OS << "do ... while ";
4995  if (Stmt *C = D->getCond())
4996  C->printPretty(OS, Helper, Policy);
4997  }
4998 
4999  void VisitSwitchStmt(SwitchStmt *Terminator) {
5000  OS << "switch ";
5001  Terminator->getCond()->printPretty(OS, Helper, Policy);
5002  }
5003 
5004  void VisitCXXTryStmt(CXXTryStmt *CS) {
5005  OS << "try ...";
5006  }
5007 
5008  void VisitSEHTryStmt(SEHTryStmt *CS) {
5009  OS << "__try ...";
5010  }
5011 
5012  void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) {
5013  if (Stmt *Cond = C->getCond())
5014  Cond->printPretty(OS, Helper, Policy);
5015  OS << " ? ... : ...";
5016  }
5017 
5018  void VisitChooseExpr(ChooseExpr *C) {
5019  OS << "__builtin_choose_expr( ";
5020  if (Stmt *Cond = C->getCond())
5021  Cond->printPretty(OS, Helper, Policy);
5022  OS << " )";
5023  }
5024 
5025  void VisitIndirectGotoStmt(IndirectGotoStmt *I) {
5026  OS << "goto *";
5027  if (Stmt *T = I->getTarget())
5028  T->printPretty(OS, Helper, Policy);
5029  }
5030 
5031  void VisitBinaryOperator(BinaryOperator* B) {
5032  if (!B->isLogicalOp()) {
5033  VisitExpr(B);
5034  return;
5035  }
5036 
5037  if (B->getLHS())
5038  B->getLHS()->printPretty(OS, Helper, Policy);
5039 
5040  switch (B->getOpcode()) {
5041  case BO_LOr:
5042  OS << " || ...";
5043  return;
5044  case BO_LAnd:
5045  OS << " && ...";
5046  return;
5047  default:
5048  llvm_unreachable("Invalid logical operator.");
5049  }
5050  }
5051 
5052  void VisitExpr(Expr *E) {
5053  E->printPretty(OS, Helper, Policy);
5054  }
5055 
5056 public:
5057  void print(CFGTerminator T) {
5058  if (T.isTemporaryDtorsBranch())
5059  OS << "(Temp Dtor) ";
5060  Visit(T.getStmt());
5061  }
5062 };
5063 
5064 } // namespace
5065 
5066 static void print_initializer(raw_ostream &OS, StmtPrinterHelper &Helper,
5067  const CXXCtorInitializer *I) {
5068  if (I->isBaseInitializer())
5069  OS << I->getBaseClass()->getAsCXXRecordDecl()->getName();
5070  else if (I->isDelegatingInitializer())
5072  else
5073  OS << I->getAnyMember()->getName();
5074  OS << "(";
5075  if (Expr *IE = I->getInit())
5076  IE->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
5077  OS << ")";
5078 
5079  if (I->isBaseInitializer())
5080  OS << " (Base initializer)";
5081  else if (I->isDelegatingInitializer())
5082  OS << " (Delegating initializer)";
5083  else
5084  OS << " (Member initializer)";
5085 }
5086 
5087 static void print_construction_context(raw_ostream &OS,
5088  StmtPrinterHelper &Helper,
5089  const ConstructionContext *CC) {
5091  switch (CC->getKind()) {
5093  OS << ", ";
5094  const auto *SICC = cast<SimpleConstructorInitializerConstructionContext>(CC);
5095  print_initializer(OS, Helper, SICC->getCXXCtorInitializer());
5096  return;
5097  }
5099  OS << ", ";
5100  const auto *CICC =
5101  cast<CXX17ElidedCopyConstructorInitializerConstructionContext>(CC);
5102  print_initializer(OS, Helper, CICC->getCXXCtorInitializer());
5103  Stmts.push_back(CICC->getCXXBindTemporaryExpr());
5104  break;
5105  }
5107  const auto *SDSCC = cast<SimpleVariableConstructionContext>(CC);
5108  Stmts.push_back(SDSCC->getDeclStmt());
5109  break;
5110  }
5112  const auto *CDSCC = cast<CXX17ElidedCopyVariableConstructionContext>(CC);
5113  Stmts.push_back(CDSCC->getDeclStmt());
5114  Stmts.push_back(CDSCC->getCXXBindTemporaryExpr());
5115  break;
5116  }
5118  const auto *NECC = cast<NewAllocatedObjectConstructionContext>(CC);
5119  Stmts.push_back(NECC->getCXXNewExpr());
5120  break;
5121  }
5123  const auto *RSCC = cast<SimpleReturnedValueConstructionContext>(CC);
5124  Stmts.push_back(RSCC->getReturnStmt());
5125  break;
5126  }
5128  const auto *RSCC =
5129  cast<CXX17ElidedCopyReturnedValueConstructionContext>(CC);
5130  Stmts.push_back(RSCC->getReturnStmt());
5131  Stmts.push_back(RSCC->getCXXBindTemporaryExpr());
5132  break;
5133  }
5135  const auto *TOCC = cast<SimpleTemporaryObjectConstructionContext>(CC);
5136  Stmts.push_back(TOCC->getCXXBindTemporaryExpr());
5137  Stmts.push_back(TOCC->getMaterializedTemporaryExpr());
5138  break;
5139  }
5141  const auto *TOCC = cast<ElidedTemporaryObjectConstructionContext>(CC);
5142  Stmts.push_back(TOCC->getCXXBindTemporaryExpr());
5143  Stmts.push_back(TOCC->getMaterializedTemporaryExpr());
5144  Stmts.push_back(TOCC->getConstructorAfterElision());
5145  break;
5146  }
5148  const auto *ACC = cast<ArgumentConstructionContext>(CC);
5149  if (const Stmt *BTE = ACC->getCXXBindTemporaryExpr()) {
5150  OS << ", ";
5151  Helper.handledStmt(const_cast<Stmt *>(BTE), OS);
5152  }
5153  OS << ", ";
5154  Helper.handledStmt(const_cast<Expr *>(ACC->getCallLikeExpr()), OS);
5155  OS << "+" << ACC->getIndex();
5156  return;
5157  }
5158  }
5159  for (auto I: Stmts)
5160  if (I) {
5161  OS << ", ";
5162  Helper.handledStmt(const_cast<Stmt *>(I), OS);
5163  }
5164 }
5165 
5166 static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
5167  const CFGElement &E) {
5168  if (Optional<CFGStmt> CS = E.getAs<CFGStmt>()) {
5169  const Stmt *S = CS->getStmt();
5170  assert(S != nullptr && "Expecting non-null Stmt");
5171 
5172  // special printing for statement-expressions.
5173  if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) {
5174  const CompoundStmt *Sub = SE->getSubStmt();
5175 
5176  auto Children = Sub->children();
5177  if (Children.begin() != Children.end()) {
5178  OS << "({ ... ; ";
5179  Helper.handledStmt(*SE->getSubStmt()->body_rbegin(),OS);
5180  OS << " })\n";
5181  return;
5182  }
5183  }
5184  // special printing for comma expressions.
5185  if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) {
5186  if (B->getOpcode() == BO_Comma) {
5187  OS << "... , ";
5188  Helper.handledStmt(B->getRHS(),OS);
5189  OS << '\n';
5190  return;
5191  }
5192  }
5193  S->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
5194 
5195  if (auto VTC = E.getAs<CFGCXXRecordTypedCall>()) {
5196  if (isa<CXXOperatorCallExpr>(S))
5197  OS << " (OperatorCall)";
5198  OS << " (CXXRecordTypedCall";
5199  print_construction_context(OS, Helper, VTC->getConstructionContext());
5200  OS << ")";
5201  } else if (isa<CXXOperatorCallExpr>(S)) {
5202  OS << " (OperatorCall)";
5203  } else if (isa<CXXBindTemporaryExpr>(S)) {
5204  OS << " (BindTemporary)";
5205  } else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) {
5206  OS << " (CXXConstructExpr";
5208  print_construction_context(OS, Helper, CE->getConstructionContext());
5209  }
5210  OS << ", " << CCE->getType().getAsString() << ")";
5211  } else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) {
5212  OS << " (" << CE->getStmtClassName() << ", "
5213  << CE->getCastKindName()
5214  << ", " << CE->getType().getAsString()
5215  << ")";
5216  }
5217 
5218  // Expressions need a newline.
5219  if (isa<Expr>(S))
5220  OS << '\n';
5221  } else if (Optional<CFGInitializer> IE = E.getAs<CFGInitializer>()) {
5222  print_initializer(OS, Helper, IE->getInitializer());
5223  OS << '\n';
5224  } else if (Optional<CFGAutomaticObjDtor> DE =
5225  E.getAs<CFGAutomaticObjDtor>()) {
5226  const VarDecl *VD = DE->getVarDecl();
5227  Helper.handleDecl(VD, OS);
5228 
5229  ASTContext &ACtx = VD->getASTContext();
5230  QualType T = VD->getType();
5231  if (T->isReferenceType())
5232  T = getReferenceInitTemporaryType(VD->getInit(), nullptr);
5233  if (const ArrayType *AT = ACtx.getAsArrayType(T))
5234  T = ACtx.getBaseElementType(AT);
5235 
5236  OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()";
5237  OS << " (Implicit destructor)\n";
5238  } else if (Optional<CFGLifetimeEnds> DE = E.getAs<CFGLifetimeEnds>()) {
5239  const VarDecl *VD = DE->getVarDecl();
5240  Helper.handleDecl(VD, OS);
5241 
5242  OS << " (Lifetime ends)\n";
5243  } else if (Optional<CFGLoopExit> LE = E.getAs<CFGLoopExit>()) {
5244  const Stmt *LoopStmt = LE->getLoopStmt();
5245  OS << LoopStmt->getStmtClassName() << " (LoopExit)\n";
5246  } else if (Optional<CFGScopeBegin> SB = E.getAs<CFGScopeBegin>()) {
5247  OS << "CFGScopeBegin(";
5248  if (const VarDecl *VD = SB->getVarDecl())
5249  OS << VD->getQualifiedNameAsString();
5250  OS << ")\n";
5251  } else if (Optional<CFGScopeEnd> SE = E.getAs<CFGScopeEnd>()) {
5252  OS << "CFGScopeEnd(";
5253  if (const VarDecl *VD = SE->getVarDecl())
5254  OS << VD->getQualifiedNameAsString();
5255  OS << ")\n";
5256  } else if (Optional<CFGNewAllocator> NE = E.getAs<CFGNewAllocator>()) {
5257  OS << "CFGNewAllocator(";
5258  if (const CXXNewExpr *AllocExpr = NE->getAllocatorExpr())
5259  AllocExpr->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
5260  OS << ")\n";
5261  } else if (Optional<CFGDeleteDtor> DE = E.getAs<CFGDeleteDtor>()) {
5262  const CXXRecordDecl *RD = DE->getCXXRecordDecl();
5263  if (!RD)
5264  return;
5265  CXXDeleteExpr *DelExpr =
5266  const_cast<CXXDeleteExpr*>(DE->getDeleteExpr());
5267  Helper.handledStmt(cast<Stmt>(DelExpr->getArgument()), OS);
5268  OS << "->~" << RD->getName().str() << "()";
5269  OS << " (Implicit destructor)\n";
5270  } else if (Optional<CFGBaseDtor> BE = E.getAs<CFGBaseDtor>()) {
5271  const CXXBaseSpecifier *BS = BE->getBaseSpecifier();
5272  OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()";
5273  OS << " (Base object destructor)\n";
5274  } else if (Optional<CFGMemberDtor> ME = E.getAs<CFGMemberDtor>()) {
5275  const FieldDecl *FD = ME->getFieldDecl();
5276  const Type *T = FD->getType()->getBaseElementTypeUnsafe();
5277  OS << "this->" << FD->getName();
5278  OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()";
5279  OS << " (Member object destructor)\n";
5280  } else if (Optional<CFGTemporaryDtor> TE = E.getAs<CFGTemporaryDtor>()) {
5281  const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr();
5282  OS << "~";
5283  BT->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
5284  OS << "() (Temporary object destructor)\n";
5285  }
5286 }
5287 
5288 static void print_block(raw_ostream &OS, const CFG* cfg,
5289  const CFGBlock &B,
5290  StmtPrinterHelper &Helper, bool print_edges,
5291  bool ShowColors) {
5292  Helper.setBlockID(B.getBlockID());
5293 
5294  // Print the header.
5295  if (ShowColors)
5296  OS.changeColor(raw_ostream::YELLOW, true);
5297 
5298  OS << "\n [B" << B.getBlockID();
5299 
5300  if (&B == &cfg->getEntry())
5301  OS << " (ENTRY)]\n";
5302  else if (&B == &cfg->getExit())
5303  OS << " (EXIT)]\n";
5304  else if (&B == cfg->getIndirectGotoBlock())
5305  OS << " (INDIRECT GOTO DISPATCH)]\n";
5306  else if (B.hasNoReturnElement())
5307  OS << " (NORETURN)]\n";
5308  else
5309  OS << "]\n";
5310 
5311  if (ShowColors)
5312  OS.resetColor();
5313 
5314  // Print the label of this block.
5315  if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) {
5316  if (print_edges)
5317  OS << " ";
5318 
5319  if (LabelStmt *L = dyn_cast<LabelStmt>(Label))
5320  OS << L->getName();
5321  else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) {
5322  OS << "case ";
5323  if (C->getLHS())
5324  C->getLHS()->printPretty(OS, &Helper,
5325  PrintingPolicy(Helper.getLangOpts()));
5326  if (C->getRHS()) {
5327  OS << " ... ";
5328  C->getRHS()->printPretty(OS, &Helper,
5329  PrintingPolicy(Helper.getLangOpts()));
5330  }
5331  } else if (isa<DefaultStmt>(Label))
5332  OS << "default";
5333  else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) {
5334  OS << "catch (";
5335  if (CS->getExceptionDecl())
5336  CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper.getLangOpts()),
5337  0);
5338  else
5339  OS << "...";
5340  OS << ")";
5341  } else if (SEHExceptStmt *ES = dyn_cast<SEHExceptStmt>(Label)) {
5342  OS << "__except (";
5343  ES->getFilterExpr()->printPretty(OS, &Helper,
5344  PrintingPolicy(Helper.getLangOpts()), 0);
5345  OS << ")";
5346  } else
5347  llvm_unreachable("Invalid label statement in CFGBlock.");
5348 
5349  OS << ":\n";
5350  }
5351 
5352  // Iterate through the statements in the block and print them.
5353  unsigned j = 1;
5354 
5355  for (CFGBlock::const_iterator I = B.begin(), E = B.end() ;
5356  I != E ; ++I, ++j ) {
5357  // Print the statement # in the basic block and the statement itself.
5358  if (print_edges)
5359  OS << " ";
5360 
5361  OS << llvm::format("%3d", j) << ": ";
5362 
5363  Helper.setStmtID(j);
5364 
5365  print_elem(OS, Helper, *I);
5366  }
5367 
5368  // Print the terminator of this block.
5369  if (B.getTerminator()) {
5370  if (ShowColors)
5371  OS.changeColor(raw_ostream::GREEN);
5372 
5373  OS << " T: ";
5374 
5375  Helper.setBlockID(-1);
5376 
5377  PrintingPolicy PP(Helper.getLangOpts());
5378  CFGBlockTerminatorPrint TPrinter(OS, &Helper, PP);
5379  TPrinter.print(B.getTerminator());
5380  OS << '\n';
5381 
5382  if (ShowColors)
5383  OS.resetColor();
5384  }
5385 
5386  if (print_edges) {
5387  // Print the predecessors of this block.
5388  if (!B.pred_empty()) {
5389  const raw_ostream::Colors Color = raw_ostream::BLUE;
5390  if (ShowColors)
5391  OS.changeColor(Color);
5392  OS << " Preds " ;
5393  if (ShowColors)
5394  OS.resetColor();
5395  OS << '(' << B.pred_size() << "):";
5396  unsigned i = 0;
5397 
5398  if (ShowColors)
5399  OS.changeColor(Color);
5400 
5401  for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end();
5402  I != E; ++I, ++i) {
5403  if (i % 10 == 8)
5404  OS << "\n ";
5405 
5406  CFGBlock *B = *I;
5407  bool Reachable = true;
5408  if (!B) {
5409  Reachable = false;
5410  B = I->getPossiblyUnreachableBlock();
5411  }
5412 
5413  OS << " B" << B->getBlockID();
5414  if (!Reachable)
5415  OS << "(Unreachable)";
5416  }
5417 
5418  if (ShowColors)
5419  OS.resetColor();
5420 
5421  OS << '\n';
5422  }
5423 
5424  // Print the successors of this block.
5425  if (!B.succ_empty()) {
5426  const raw_ostream::Colors Color = raw_ostream::MAGENTA;
5427  if (ShowColors)
5428  OS.changeColor(Color);
5429  OS << " Succs ";
5430  if (ShowColors)
5431  OS.resetColor();
5432  OS << '(' << B.succ_size() << "):";
5433  unsigned i = 0;
5434 
5435  if (ShowColors)
5436  OS.changeColor(Color);
5437 
5438  for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end();
5439  I != E; ++I, ++i) {
5440  if (i % 10 == 8)
5441  OS << "\n ";
5442 
5443  CFGBlock *B = *I;
5444 
5445  bool Reachable = true;
5446  if (!B) {
5447  Reachable = false;
5448  B = I->getPossiblyUnreachableBlock();
5449  }
5450 
5451  if (B) {
5452  OS << " B" << B->getBlockID();
5453  if (!Reachable)
5454  OS << "(Unreachable)";
5455  }
5456  else {
5457  OS << " NULL";
5458  }
5459  }
5460 
5461  if (ShowColors)
5462  OS.resetColor();
5463  OS << '\n';
5464  }
5465  }
5466 }
5467 
5468 /// dump - A simple pretty printer of a CFG that outputs to stderr.
5469 void CFG::dump(const LangOptions &LO, bool ShowColors) const {
5470  print(llvm::errs(), LO, ShowColors);
5471 }
5472 
5473 /// print - A simple pretty printer of a CFG that outputs to an ostream.
5474 void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const {
5475  StmtPrinterHelper Helper(this, LO);
5476 
5477  // Print the entry block.
5478  print_block(OS, this, getEntry(), Helper, true, ShowColors);
5479 
5480  // Iterate through the CFGBlocks and print them one by one.
5481  for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) {
5482  // Skip the entry block, because we already printed it.
5483  if (&(**I) == &getEntry() || &(**I) == &getExit())
5484  continue;
5485 
5486  print_block(OS, this, **I, Helper, true, ShowColors);
5487  }
5488 
5489  // Print the exit block.
5490  print_block(OS, this, getExit(), Helper, true, ShowColors);
5491  OS << '\n';
5492  OS.flush();
5493 }
5494 
5495 /// dump - A simply pretty printer of a CFGBlock that outputs to stderr.
5496 void CFGBlock::dump(const CFG* cfg, const LangOptions &LO,
5497  bool ShowColors) const {
5498  print(llvm::errs(), cfg, LO, ShowColors);
5499 }
5500 
5501 LLVM_DUMP_METHOD void CFGBlock::dump() const {
5502  dump(getParent(), LangOptions(), false);
5503 }
5504 
5505 /// print - A simple pretty printer of a CFGBlock that outputs to an ostream.
5506 /// Generally this will only be called from CFG::print.
5507 void CFGBlock::print(raw_ostream &OS, const CFG* cfg,
5508  const LangOptions &LO, bool ShowColors) const {
5509  StmtPrinterHelper Helper(cfg, LO);
5510  print_block(OS, cfg, *this, Helper, true, ShowColors);
5511  OS << '\n';
5512 }
5513 
5514 /// printTerminator - A simple pretty printer of the terminator of a CFGBlock.
5515 void CFGBlock::printTerminator(raw_ostream &OS,
5516  const LangOptions &LO) const {
5517  CFGBlockTerminatorPrint TPrinter(OS, nullptr, PrintingPolicy(LO));
5518  TPrinter.print(getTerminator());
5519 }
5520 
5522  Stmt *Terminator = this->Terminator;
5523  if (!Terminator)
5524  return nullptr;
5525 
5526  Expr *E = nullptr;
5527 
5528  switch (Terminator->getStmtClass()) {
5529  default:
5530  break;
5531 
5532  case Stmt::CXXForRangeStmtClass:
5533  E = cast<CXXForRangeStmt>(Terminator)->getCond();
5534  break;
5535 
5536  case Stmt::ForStmtClass:
5537  E = cast<ForStmt>(Terminator)->getCond();
5538  break;
5539 
5540  case Stmt::WhileStmtClass:
5541  E = cast<WhileStmt>(Terminator)->getCond();
5542  break;
5543 
5544  case Stmt::DoStmtClass:
5545  E = cast<DoStmt>(Terminator)->getCond();
5546  break;
5547 
5548  case Stmt::IfStmtClass:
5549  E = cast<IfStmt>(Terminator)->getCond();
5550  break;
5551 
5552  case Stmt::ChooseExprClass:
5553  E = cast<ChooseExpr>(Terminator)->getCond();
5554  break;
5555 
5556  case Stmt::IndirectGotoStmtClass:
5557  E = cast<IndirectGotoStmt>(Terminator)->getTarget();
5558  break;
5559 
5560  case Stmt::SwitchStmtClass:
5561  E = cast<SwitchStmt>(Terminator)->getCond();
5562  break;
5563 
5564  case Stmt::BinaryConditionalOperatorClass:
5565  E = cast<BinaryConditionalOperator>(Terminator)->getCond();
5566  break;
5567 
5568  case Stmt::ConditionalOperatorClass:
5569  E = cast<ConditionalOperator>(Terminator)->getCond();
5570  break;
5571 
5572  case Stmt::BinaryOperatorClass: // '&&' and '||'
5573  E = cast<BinaryOperator>(Terminator)->getLHS();
5574  break;
5575 
5576  case Stmt::ObjCForCollectionStmtClass:
5577  return Terminator;
5578  }
5579 
5580  if (!StripParens)
5581  return E;
5582 
5583  return E ? E->IgnoreParens() : nullptr;
5584 }
5585 
5586 //===----------------------------------------------------------------------===//
5587 // CFG Graphviz Visualization
5588 //===----------------------------------------------------------------------===//
5589 
5590 #ifndef NDEBUG
5591 static StmtPrinterHelper* GraphHelper;
5592 #endif
5593 
5594 void CFG::viewCFG(const LangOptions &LO) const {
5595 #ifndef NDEBUG
5596  StmtPrinterHelper H(this, LO);
5597  GraphHelper = &H;
5598  llvm::ViewGraph(this,"CFG");
5599  GraphHelper = nullptr;
5600 #endif
5601 }
5602 
5603 namespace llvm {
5604 
5605 template<>
5606 struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits {
5607  DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
5608 
5609  static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) {
5610 #ifndef NDEBUG
5611  std::string OutSStr;
5612  llvm::raw_string_ostream Out(OutSStr);
5613  print_block(Out,Graph, *Node, *GraphHelper, false, false);
5614  std::string& OutStr = Out.str();
5615 
5616  if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
5617 
5618  // Process string output to make it nicer...
5619  for (unsigned i = 0; i != OutStr.length(); ++i)
5620  if (OutStr[i] == '\n') { // Left justify
5621  OutStr[i] = '\\';
5622  OutStr.insert(OutStr.begin()+i+1, 'l');
5623  }
5624 
5625  return OutStr;
5626 #else
5627  return {};
5628 #endif
5629  }
5630 };
5631 
5632 } // namespace llvm
Expr * getInc()
Definition: Stmt.h:2369
unsigned getNumSemanticExprs() const
Definition: Expr.h:5647
const Expr * getSubExpr() const
Definition: Expr.h:923
bool isBaseInitializer() const
Determine whether this initializer is initializing a base class.
Definition: DeclCXX.h:2403
bool isNoReturn() const
Determines whether this function is known to be &#39;noreturn&#39;, through an attribute on its declaration o...
Definition: Decl.cpp:2992
Defines the clang::ASTContext interface.
const BlockDecl * getBlockDecl() const
Definition: Expr.h:5475
Represents C++ allocator call.
Definition: CFG.h:239
const CXXDestructorDecl * getDestructor() const
Definition: ExprCXX.h:1268
Represents a function declaration or definition.
Definition: Decl.h:1743
Expr * getInit() const
Get the initializer.
Definition: DeclCXX.h:2532
CompoundStmt * getBlock() const
Definition: Stmt.h:3147
A class which contains all the information about a particular captured value.
Definition: Decl.h:3869
pred_iterator pred_end()
Definition: CFG.h:733
PointerType - C99 6.7.5.1 - Pointer Declarators.
Definition: Type.h:2549
QualType getPointeeType() const
Definition: Type.h:2562
A (possibly-)qualified type.
Definition: Type.h:639
bool isBlockPointerType() const
Definition: Type.h:6353
base_class_range bases()
Definition: DeclCXX.h:822
Expr * getCond() const
Definition: Expr.h:4063
static SourceLocation GetEndLoc(Decl *D)
Definition: CFG.cpp:65
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.
const Expr * skipRValueSubobjectAdjustments(SmallVectorImpl< const Expr *> &CommaLHS, SmallVectorImpl< SubobjectAdjustment > &Adjustments) const
Walk outwards from an expression we want to bind a reference to and find the expression whose lifetim...
Definition: Expr.cpp:76
bool operator==(CanQual< T > x, CanQual< U > y)
Expr * getCond()
Definition: Stmt.h:2201
DOTGraphTraits(bool isSimple=false)
Definition: CFG.cpp:5607
ElementList::iterator iterator
Definition: CFG.h:694
succ_iterator succ_begin()
Definition: CFG.h:750
CompoundStmt * getSubStmt()
Definition: Expr.h:3858
DominatorTree GraphTraits specialization so the DominatorTree can be iterable by generic graph iterat...
Definition: Dominators.h:29
bool isReachable() const
Definition: CFG.h:662
const DeclStmt * getConditionVariableDeclStmt() const
If this ForStmt has a condition variable, return the faux DeclStmt associated with the creation of th...
Definition: Stmt.h:2364
bool EvaluateAsInt(EvalResult &Result, const ASTContext &Ctx, SideEffectsKind AllowSideEffects=SE_NoSideEffects) const
EvaluateAsInt - Return true if this is a constant which we can fold and convert to an integer...
Stmt - This represents one statement.
Definition: Stmt.h:65
FunctionType - C99 6.7.5.3 - Function Declarators.
Definition: Type.h:3367
CXXCatchStmt * getHandler(unsigned i)
Definition: StmtCXX.h:107
CFGBlock & getEntry()
Definition: CFG.h:1092
IfStmt - This represents an if/then/else.
Definition: Stmt.h:1764
StorageClass getStorageClass() const
Returns the storage class as written in the source.
Definition: Decl.h:1019
void appendScopeEnd(const VarDecl *VD, const Stmt *S, BumpVectorContext &C)
Definition: CFG.h:907
C Language Family Type Representation.
Expr * getBase() const
Definition: Expr.h:2810
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:88
Stmt * getHandlerBlock() const
Definition: StmtCXX.h:51
Opcode getOpcode() const
Definition: Expr.h:3360
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:6294
void appendLifetimeEnds(VarDecl *VD, Stmt *S, BumpVectorContext &C)
Definition: CFG.h:931
The base class of the type hierarchy.
Definition: Type.h:1414
Represents Objective-C&#39;s @throw statement.
Definition: StmtObjC.h:332
Represents C++ object destructor generated from a call to delete.
Definition: CFG.h:408
Represents an array type, per C99 6.7.5.2 - Array Declarators.
Definition: Type.h:2824
iterator begin()
Definition: CFG.h:702
Represents a call to a C++ constructor.
Definition: ExprCXX.h:1338
unsigned IgnoreDefaultsWithCoveredEnums
Definition: CFG.h:778
Represents a C++ constructor within a class.
Definition: DeclCXX.h:2562
Represents a prvalue temporary that is written into memory so that a reference can bind to it...
Definition: ExprCXX.h:4332
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:3174
unsigned succ_size() const
Definition: CFG.h:768
const CXXDestructorDecl * getDestructorDecl(ASTContext &astContext) const
Definition: CFG.cpp:4726
Stmt * getSubStmt()
Definition: Stmt.h:1597
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:1915
Represents a variable declaration or definition.
Definition: Decl.h:812
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6805
CFGBlock * getReachableBlock() const
Get the reachable block, if one exists.
Definition: CFG.h:639
const char * getName() const
Definition: Stmt.cpp:340
Stmt * getThen()
Definition: Stmt.h:1851
Describes how types, statements, expressions, and declarations should be printed. ...
Definition: PrettyPrinter.h:37
Defines the Objective-C statement AST node classes.
static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper, const CFGElement &E)
Definition: CFG.cpp:5166
A C++ throw-expression (C++ [except.throw]).
Definition: ExprCXX.h:1056
Represents an expression – generally a full-expression – that introduces cleanups to be run at the ...
Definition: ExprCXX.h:3219
static bool isAssignmentOp(Opcode Opc)
Definition: Expr.h:3451
Defines the clang::Expr interface and subclasses for C++ expressions.
const Stmt * getSubStmt() const
Definition: StmtObjC.h:379
const char * getStmtClassName() const
Definition: Stmt.cpp:74
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:1662
const AstTypeMatcher< RecordType > recordType
Matches record types (e.g.
static TryResult bothKnownTrue(TryResult R1, TryResult R2)
Definition: CFG.cpp:381
bool pred_empty() const
Definition: CFG.h:772
Stmt * getBody()
Definition: Stmt.h:2305
CFGBlock * getPossiblyUnreachableBlock() const
Get the potentially unreachable block.
Definition: CFG.h:644
void print(raw_ostream &Out, unsigned Indentation=0, bool PrintInstantiation=false) const
QualType getPointeeType() const
Definition: Type.h:2666
DeclStmt * getConditionVariableDeclStmt()
If this SwitchStmt has a condition variable, return the faux DeclStmt associated with the creation of...
Definition: Stmt.h:2086
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:154
void setLoopTarget(const Stmt *loopTarget)
Definition: CFG.h:836
static std::string getNodeLabel(const CFGBlock *Node, const CFG *Graph)
Definition: CFG.cpp:5609
field_range fields() const
Definition: Decl.h:3789
Represents a member of a struct/union/class.
Definition: Decl.h:2584
TypeSourceInfo * getTypeSourceInfo() const
Returns the declarator information for a base class or delegating initializer.
Definition: DeclCXX.h:2464
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:5515
Represents C++ object destructor implicitly generated for automatic object or temporary bound to cons...
Definition: CFG.h:383
void appendAutomaticObjDtor(VarDecl *VD, Stmt *S, BumpVectorContext &C)
Definition: CFG.h:927
bool isReferenceType() const
Definition: Type.h:6357
const CXXConstructExpr * getConstructExpr() const
Returns the CXXConstructExpr from this new-expression, or null.
Definition: ExprCXX.h:2200
succ_range succs()
Definition: CFG.h:760
clang::CharUnits operator*(clang::CharUnits::QuantityType Scale, const clang::CharUnits &CU)
Definition: CharUnits.h:207
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:2123
Expr * getSubExpr()
Definition: Expr.h:3093
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:49
iterator end()
Definition: CFG.h:1078
Represents Objective-C&#39;s @catch statement.
Definition: StmtObjC.h:77
AdjacentBlocks::const_iterator const_succ_iterator
Definition: CFG.h:726
bool isGLValue() const
Definition: Expr.h:254
IndirectGotoStmt - This represents an indirect goto.
Definition: Stmt.h:2446
Describes an C or C++ initializer list.
Definition: Expr.h:4291
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
Optional< Expr * > getArraySize()
Definition: ExprCXX.h:2138
ForStmt - This represents a &#39;for (init;cond;inc)&#39; stmt.
Definition: Stmt.h:2336
APValue Val
Val - This is the value the expression can be folded to.
Definition: Expr.h:575
LabelDecl * getDecl() const
Definition: Stmt.h:1679
Forward-declares and imports various common LLVM datatypes that clang wants to use unqualified...
void print(raw_ostream &OS, const PrintingPolicy &Policy, const Twine &PlaceHolder=Twine(), unsigned Indentation=0) const
capture_init_iterator capture_init_begin()
Retrieve the first initialization argument for this lambda expression (which initializes the first ca...
Definition: ExprCXX.h:1879
Expr * getInitializer()
The initializer of this new-expression.
Definition: ExprCXX.h:2188
Stmt * getBody()
Definition: Stmt.h:2370
CFGCallback * Observer
Definition: CFG.h:1015
child_range children()
Definition: Stmt.cpp:212
static QualType getReferenceInitTemporaryType(const Expr *Init, bool *FoundMTE=nullptr)
Retrieve the type of the temporary object whose lifetime was extended by a local reference with the g...
Definition: CFG.cpp:1568
A builtin binary operation expression such as "x + y" or "x <= y".
Definition: Expr.h:3325
Stmt * getInit()
Definition: Stmt.h:2349
CXXForRangeStmt - This represents C++0x [stmt.ranged]&#39;s ranged for statement, represented as &#39;for (ra...
Definition: StmtCXX.h:134
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:120
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:5507
bool isLinear() const
Returns true if the CFG has no branches.
Definition: CFG.cpp:4680
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:6121
CaseStmt - Represent a case statement.
Definition: Stmt.h:1430
void appendLoopExit(const Stmt *LoopStmt, BumpVectorContext &C)
Definition: CFG.h:935
Expr * getCond()
Definition: Stmt.h:2368
bool isInt() const
Definition: APValue.h:313
CastExpr - Base class for type casts, including both implicit casts (ImplicitCastExpr) and explicit c...
Definition: Expr.h:3041
Represents binding an expression to a temporary.
Definition: ExprCXX.h:1289
CXXTemporary * getTemporary()
Definition: ExprCXX.h:1308
FieldDecl * getAnyMember() const
Definition: DeclCXX.h:2476
A C++ lambda expression, which produces a function object (of unspecified type) that can be invoked l...
Definition: ExprCXX.h:1734
bool hasTrivialDestructor() const
Determine whether this class has a trivial destructor (C++ [class.dtor]p3)
Definition: DeclCXX.h:1488
bool isTypeDependent() const
isTypeDependent - Determines whether this expression is type-dependent (C++ [temp.dep.expr]), which means that its type could change from one template instantiation to the next.
Definition: Expr.h:169
child_range children()
Definition: Stmt.h:1377
CXXDestructorDecl * getDestructor() const
Returns the destructor decl for this class.
Definition: DeclCXX.cpp:1724
VarDecl * getConditionVariable() const
Retrieve the variable declared in this "for" statement, if any.
Definition: Stmt.cpp:894
bool getNoReturn() const
Definition: Type.h:3524
Stmt * getBody()
Definition: Stmt.h:2041
Stmt * getInit()
Definition: Stmt.h:1907
arg_iterator placement_arg_end()
Definition: ExprCXX.h:2229
llvm::DenseMap< const Stmt *, const CFGBlock * > ForcedBlkExprs
Definition: CFG.h:1012
CFGBlockListTy::const_iterator const_iterator
Definition: CFG.h:1070
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:1277
CXXRecordDecl * getAsCXXRecordDecl() const
Retrieves the CXXRecordDecl that this type refers to, either because the type is a RecordType or beca...
Definition: Type.cpp:1636
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3699
bool isDelegatingInitializer() const
Determine whether this initializer is creating a delegating constructor.
Definition: DeclCXX.h:2431
UnaryExprOrTypeTraitExpr - expression with either a type or (unevaluated) expression operand...
Definition: Expr.h:2260
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:3933
Represents a single basic block in a source-level CFG.
Definition: CFG.h:551
ConstantExpr - An expression that occurs in a constant context.
Definition: Expr.h:937
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:4783
This represents one expression.
Definition: Expr.h:108
Defines the clang::LangOptions interface.
Stmt * getTerminatorCondition(bool StripParens=true)
Definition: CFG.cpp:5521
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:89
DeclStmt * getEndStmt()
Definition: StmtCXX.h:165
SourceLocation End
std::string Label
Represents a source-level, intra-procedural CFG that represents the control-flow of a Stmt...
Definition: CFG.h:1002
Represents a C++ functional cast expression that builds a temporary object.
Definition: ExprCXX.h:1666
BlockExpr - Adaptor class for mixing a BlockDecl with expressions.
Definition: Expr.h:5461
Represents a C++ destructor within a class.
Definition: DeclCXX.h:2826
bool succ_empty() const
Definition: CFG.h:769
VarDecl * getExceptionDecl() const
Definition: StmtCXX.h:49
Expr * getCallee()
Definition: Expr.h:2552
unsigned getNumInits() const
Definition: Expr.h:4321
Represents C++ constructor call.
Definition: CFG.h:150
QualType getArgumentType() const
Definition: Expr.h:2297
#define bool
Definition: stdbool.h:15
Stmt * getBody()
Definition: Stmt.h:2213
const CompoundStmt * getSynchBody() const
Definition: StmtObjC.h:297
ElementList::const_iterator const_iterator
Definition: CFG.h:695
Expr * getRHS()
Definition: Stmt.h:1531
bool isTemporaryDtorsBranch() const
Definition: CFG.h:512
Represents Objective-C&#39;s @synchronized statement.
Definition: StmtObjC.h:277
SourceLocation Begin
DOTGraphTraits(bool isSimple=false)
CXXTryStmt - A C++ try block, including all handlers.
Definition: StmtCXX.h:68
FunctionDecl * getDirectCallee()
If the callee is a FunctionDecl, return it. Otherwise return null.
Definition: Expr.h:2570
const AstTypeMatcher< ArrayType > arrayType
Matches all kinds of arrays.
std::reverse_iterator< body_iterator > reverse_body_iterator
Definition: Stmt.h:1345
QualType getType() const
Definition: Expr.h:130
static void print_initializer(raw_ostream &OS, StmtPrinterHelper &Helper, const CXXCtorInitializer *I)
Definition: CFG.cpp:5066
LabelDecl * getLabel() const
Definition: Stmt.h:2420
StorageDuration getStorageDuration() const
Retrieve the storage duration for the materialized temporary.
Definition: ExprCXX.h:4376
An expression that sends a message to the given Objective-C object or class.
Definition: ExprObjC.h:950
SwitchCase * getSwitchCaseList()
Definition: Stmt.h:2098
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:1934
static bool CanThrow(Expr *E, ASTContext &Ctx)
Definition: CFG.cpp:2415
const Type * getBaseElementTypeUnsafe() const
Get the base element type of this type, potentially discarding type qualifiers.
Definition: Type.h:6745
Expr * getCond()
Definition: Stmt.h:1839
ValueDecl * getDecl()
Definition: Expr.h:1147
Represents C++ object destructor implicitly generated for base object in destructor.
Definition: CFG.h:434
The result type of a method or function.
QualType getDestroyedType() const
Retrieve the type being destroyed.
Definition: ExprCXX.cpp:224
const Expr * getSubExpr() const
Definition: ExprCXX.h:1312
bool isNull() const
Return true if this QualType doesn&#39;t point to a type yet.
Definition: Type.h:704
DoStmt - This represents a &#39;do/while&#39; stmt.
Definition: Stmt.h:2280
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:1229
RecordDecl * getDecl() const
Definition: Type.h:4427
Expr * getArgument()
Definition: ExprCXX.h:2314
void appendStmt(Stmt *statement, BumpVectorContext &C)
Definition: CFG.h:872
bool EvaluateAsRValue(EvalResult &Result, const ASTContext &Ctx, bool InConstantContext=false) const
EvaluateAsRValue - Return true if this is a constant which we can fold to an rvalue using any crazy t...
CFGTerminator getTerminator()
Definition: CFG.h:839
OpaqueValueExpr - An expression referring to an opaque object of a fixed type and value class...
Definition: Expr.h:978
Kind
PseudoObjectExpr - An expression which accesses a pseudo-object l-value.
Definition: Expr.h:5583
Construction context can be seen as a linked list of multiple layers.
Encodes a location in the source.
Stmt * getLabel()
Definition: CFG.h:850
unsigned getNumHandlers() const
Definition: StmtCXX.h:106
Expr * getSubExpr() const
Definition: Expr.h:1964
Represents a C++ temporary.
Definition: ExprCXX.h:1257
Represents a new-expression for memory allocation and constructor calls, e.g: "new CXXNewExpr(foo)"...
Definition: ExprCXX.h:2012
Expr * getLHS()
Definition: Stmt.h:1519
void setLabel(Stmt *Statement)
Definition: CFG.h:835
static std::unique_ptr< CFG > buildCFG(const Decl *D, Stmt *AST, ASTContext *C, const BuildOptions &BO)
Builds a CFG from an AST.
Definition: CFG.cpp:4674
ASTContext & getASTContext() const LLVM_READONLY
Definition: DeclBase.cpp:376
iterator insertScopeEnd(iterator I, VarDecl *VD, Stmt *S)
Definition: CFG.h:976
Stmt * getElse()
Definition: Stmt.h:1860
DeclStmt - Adaptor class for mixing declarations with statements and expressions. ...
Definition: Stmt.h:1170
bool PruneTriviallyFalseEdges
Definition: CFG.h:1016
reverse_body_iterator body_rend()
Definition: Stmt.h:1351
QualType getBaseElementType(const ArrayType *VAT) const
Return the innermost element type of an array type.
const ConstantArrayType * getAsConstantArrayType(QualType T) const
Definition: ASTContext.h:2437
Expr * getCond()
Definition: Stmt.h:2029
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:182
static void print_block(raw_ostream &OS, const CFG *cfg, const CFGBlock &B, StmtPrinterHelper &Helper, bool print_edges, bool ShowColors)
Definition: CFG.cpp:5288
const ArrayType * getAsArrayType(QualType T) const
Type Query functions.
bool isArray() const
Definition: ExprCXX.h:2136
decl_iterator decl_begin()
Definition: Stmt.h:1224
bool isValueDependent() const
isValueDependent - Determines whether this expression is value-dependent (C++ [temp.dep.constexpr]).
Definition: Expr.h:151
bool isKnownToHaveBooleanValue() const
isKnownToHaveBooleanValue - Return true if this is an integer expression that is known to return 0 or...
Definition: Expr.cpp:134
reverse_decl_iterator decl_rbegin()
Definition: Stmt.h:1231
ImplicitCastExpr - Allows us to explicitly represent implicit type conversions, which have no direct ...
Definition: Expr.h:3165
static bool isCXXRecordTypedCall(Expr *E)
Returns true when call expression CE needs to be represented by CFGCXXRecordTypedCall, as opposed to a regular CFGStmt.
Definition: CFG.h:182
static QualType findBoundMemberType(const Expr *expr)
Given an expression of bound-member type, find the type of the member.
Definition: Expr.cpp:2625
Expr ** getInits()
Retrieve the set of initializers.
Definition: Expr.h:4324
void appendScopeBegin(const VarDecl *VD, const Stmt *S, BumpVectorContext &C)
Definition: CFG.h:897
iterator begin()
Definition: CFG.h:1077
static bool isLogicalOp(Opcode Opc)
Definition: Expr.h:3448
static const Expr * tryTransformToIntOrEnumConstant(const Expr *E)
Helper for tryNormalizeBinaryOperator.
Definition: CFG.cpp:74
VarDecl * getConditionVariable()
Retrieve the variable declared in this "switch" statement, if any.
Definition: Stmt.cpp:957
DeclStmt * getConditionVariableDeclStmt()
If this WhileStmt has a condition variable, return the faux DeclStmt associated with the creation of ...
Definition: Stmt.h:2241
void dump() const
Definition: CFG.cpp:5501
succ_iterator succ_end()
Definition: CFG.h:751
StmtExpr - This is the GNU Statement Expression extension: ({int X=4; X;}).
Definition: Expr.h:3842
bool isArgumentType() const
Definition: Expr.h:2296
Represents end of a scope implicitly generated by the compiler after the last Stmt in a CompoundStmt&#39;...
Definition: CFG.h:335
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:3365
Defines various enumerations that describe declaration and type specifiers.
AddrLabelExpr - The GNU address of label extension, representing &&label.
Definition: Expr.h:3798
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:3739
Dataflow Directional Tag Classes.
VarDecl * getConditionVariable()
Retrieve the variable declared in this "while" statement, if any.
Definition: Stmt.cpp:1013
DeclContext - This is used only as base class of specific decl types that can act as declaration cont...
Definition: DeclBase.h:1264
EvalResult is a struct with detailed info about an evaluated expression.
Definition: Expr.h:573
Represents a delete expression for memory deallocation and destructor calls, e.g. ...
Definition: ExprCXX.h:2272
ArrayRef< Capture > captures() const
Definition: Decl.h:3990
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
const Stmt * stripLabelLikeStatements() const
Strip off all label-like statements.
Definition: Stmt.cpp:144
static const VariableArrayType * FindVA(const Type *t)
Definition: CFG.cpp:1259
void appendCXXRecordTypedCall(Expr *E, const ConstructionContext *CC, BumpVectorContext &C)
Definition: CFG.h:881
const Expr * getInit() const
Definition: Decl.h:1219
unsigned pred_size() const
Definition: CFG.h:771
StmtClass getStmtClass() const
Definition: Stmt.h:1053
static StmtPrinterHelper * GraphHelper
Definition: CFG.cpp:5591
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:2233
bool isAnyDestructorNoReturn() const
Returns true if the class destructor, or any implicitly invoked destructors are marked noreturn...
Definition: DeclCXX.cpp:1737
const Type * getBaseClass() const
If this is a base class initializer, returns the type of the base class.
Definition: DeclCXX.cpp:2335
SEHExceptStmt * getExceptHandler() const
Returns 0 if not defined.
Definition: Stmt.cpp:1105
const Decl * getSingleDecl() const
Definition: Stmt.h:1185
FunctionType::ExtInfo getFunctionExtInfo(const Type &t)
Definition: Type.h:6246
const Expr * getSynchExpr() const
Definition: StmtObjC.h:305
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:620
bool isSingleDecl() const
isSingleDecl - This method returns true if this DeclStmt refers to a single Decl. ...
Definition: Stmt.h:1183
Represents the point where the lifetime of an automatic object ends.
Definition: CFG.h:284
DeclStmt * getConditionVariableDeclStmt()
If this IfStmt has a condition variable, return the faux DeclStmt associated with the creation of tha...
Definition: Stmt.h:1895
Stmt * getStmt()
Definition: CFG.h:509
Represents a single point (AST node) in the program that requires attention during construction of an...
Expr * IgnoreParenImpCasts() LLVM_READONLY
Skip past any parentheses and implicit casts which might surround this expression until reaching a fi...
Definition: Expr.cpp:2809
llvm::APInt getValue() const
Definition: Expr.h:1325
Represents a __leave statement.
Definition: Stmt.h:3215
LabelDecl * getLabel() const
Definition: Expr.h:3820
SwitchStmt - This represents a &#39;switch&#39; stmt.
Definition: Stmt.h:1969
Pointer to a block type.
Definition: Type.h:2651
CFGBlock * getIndirectGotoBlock()
Definition: