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"
35 #include "clang/Basic/LLVM.h"
38 #include "clang/Basic/Specifiers.h"
39 #include "llvm/ADT/APInt.h"
40 #include "llvm/ADT/APSInt.h"
41 #include "llvm/ADT/ArrayRef.h"
42 #include "llvm/ADT/DenseMap.h"
43 #include "llvm/ADT/Optional.h"
44 #include "llvm/ADT/STLExtras.h"
45 #include "llvm/ADT/SetVector.h"
46 #include "llvm/ADT/SmallPtrSet.h"
47 #include "llvm/ADT/SmallVector.h"
48 #include "llvm/Support/Allocator.h"
49 #include "llvm/Support/Casting.h"
50 #include "llvm/Support/Compiler.h"
51 #include "llvm/Support/DOTGraphTraits.h"
52 #include "llvm/Support/ErrorHandling.h"
53 #include "llvm/Support/Format.h"
54 #include "llvm/Support/GraphWriter.h"
55 #include "llvm/Support/SaveAndRestore.h"
56 #include "llvm/Support/raw_ostream.h"
57 #include <cassert>
58 #include <memory>
59 #include <string>
60 #include <tuple>
61 #include <utility>
62 #include <vector>
63 
64 using namespace clang;
65 
67  if (VarDecl *VD = dyn_cast<VarDecl>(D))
68  if (Expr *Ex = VD->getInit())
69  return Ex->getSourceRange().getEnd();
70  return D->getLocation();
71 }
72 
73 /// Helper for tryNormalizeBinaryOperator. Attempts to extract an IntegerLiteral
74 /// or EnumConstantDecl from the given Expr. If it fails, returns nullptr.
75 static const Expr *tryTransformToIntOrEnumConstant(const Expr *E) {
76  E = E->IgnoreParens();
77  if (isa<IntegerLiteral>(E))
78  return E;
79  if (auto *DR = dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))
80  return isa<EnumConstantDecl>(DR->getDecl()) ? DR : nullptr;
81  return nullptr;
82 }
83 
84 /// Tries to interpret a binary operator into `Decl Op Expr` form, if Expr is
85 /// an integer literal or an enum constant.
86 ///
87 /// If this fails, at least one of the returned DeclRefExpr or Expr will be
88 /// null.
89 static std::tuple<const DeclRefExpr *, BinaryOperatorKind, const Expr *>
91  BinaryOperatorKind Op = B->getOpcode();
92 
93  const Expr *MaybeDecl = B->getLHS();
94  const Expr *Constant = tryTransformToIntOrEnumConstant(B->getRHS());
95  // Expr looked like `0 == Foo` instead of `Foo == 0`
96  if (Constant == nullptr) {
97  // Flip the operator
98  if (Op == BO_GT)
99  Op = BO_LT;
100  else if (Op == BO_GE)
101  Op = BO_LE;
102  else if (Op == BO_LT)
103  Op = BO_GT;
104  else if (Op == BO_LE)
105  Op = BO_GE;
106 
107  MaybeDecl = B->getRHS();
108  Constant = tryTransformToIntOrEnumConstant(B->getLHS());
109  }
110 
111  auto *D = dyn_cast<DeclRefExpr>(MaybeDecl->IgnoreParenImpCasts());
112  return std::make_tuple(D, Op, Constant);
113 }
114 
115 /// For an expression `x == Foo && x == Bar`, this determines whether the
116 /// `Foo` and `Bar` are either of the same enumeration type, or both integer
117 /// literals.
118 ///
119 /// It's an error to pass this arguments that are not either IntegerLiterals
120 /// or DeclRefExprs (that have decls of type EnumConstantDecl)
121 static bool areExprTypesCompatible(const Expr *E1, const Expr *E2) {
122  // User intent isn't clear if they're mixing int literals with enum
123  // constants.
124  if (isa<IntegerLiteral>(E1) != isa<IntegerLiteral>(E2))
125  return false;
126 
127  // Integer literal comparisons, regardless of literal type, are acceptable.
128  if (isa<IntegerLiteral>(E1))
129  return true;
130 
131  // IntegerLiterals are handled above and only EnumConstantDecls are expected
132  // beyond this point
133  assert(isa<DeclRefExpr>(E1) && isa<DeclRefExpr>(E2));
134  auto *Decl1 = cast<DeclRefExpr>(E1)->getDecl();
135  auto *Decl2 = cast<DeclRefExpr>(E2)->getDecl();
136 
137  assert(isa<EnumConstantDecl>(Decl1) && isa<EnumConstantDecl>(Decl2));
138  const DeclContext *DC1 = Decl1->getDeclContext();
139  const DeclContext *DC2 = Decl2->getDeclContext();
140 
141  assert(isa<EnumDecl>(DC1) && isa<EnumDecl>(DC2));
142  return DC1 == DC2;
143 }
144 
145 namespace {
146 
147 class CFGBuilder;
148 
149 /// The CFG builder uses a recursive algorithm to build the CFG. When
150 /// we process an expression, sometimes we know that we must add the
151 /// subexpressions as block-level expressions. For example:
152 ///
153 /// exp1 || exp2
154 ///
155 /// When processing the '||' expression, we know that exp1 and exp2
156 /// need to be added as block-level expressions, even though they
157 /// might not normally need to be. AddStmtChoice records this
158 /// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then
159 /// the builder has an option not to add a subexpression as a
160 /// block-level expression.
161 class AddStmtChoice {
162 public:
163  enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 };
164 
165  AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {}
166 
167  bool alwaysAdd(CFGBuilder &builder,
168  const Stmt *stmt) const;
169 
170  /// Return a copy of this object, except with the 'always-add' bit
171  /// set as specified.
172  AddStmtChoice withAlwaysAdd(bool alwaysAdd) const {
173  return AddStmtChoice(alwaysAdd ? AlwaysAdd : NotAlwaysAdd);
174  }
175 
176 private:
177  Kind kind;
178 };
179 
180 /// LocalScope - Node in tree of local scopes created for C++ implicit
181 /// destructor calls generation. It contains list of automatic variables
182 /// declared in the scope and link to position in previous scope this scope
183 /// began in.
184 ///
185 /// The process of creating local scopes is as follows:
186 /// - Init CFGBuilder::ScopePos with invalid position (equivalent for null),
187 /// - Before processing statements in scope (e.g. CompoundStmt) create
188 /// LocalScope object using CFGBuilder::ScopePos as link to previous scope
189 /// and set CFGBuilder::ScopePos to the end of new scope,
190 /// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points
191 /// at this VarDecl,
192 /// - For every normal (without jump) end of scope add to CFGBlock destructors
193 /// for objects in the current scope,
194 /// - For every jump add to CFGBlock destructors for objects
195 /// between CFGBuilder::ScopePos and local scope position saved for jump
196 /// target. Thanks to C++ restrictions on goto jumps we can be sure that
197 /// jump target position will be on the path to root from CFGBuilder::ScopePos
198 /// (adding any variable that doesn't need constructor to be called to
199 /// LocalScope can break this assumption),
200 ///
201 class LocalScope {
202 public:
203  friend class const_iterator;
204 
205  using AutomaticVarsTy = BumpVector<VarDecl *>;
206 
207  /// const_iterator - Iterates local scope backwards and jumps to previous
208  /// scope on reaching the beginning of currently iterated scope.
209  class const_iterator {
210  const LocalScope* Scope = nullptr;
211 
212  /// VarIter is guaranteed to be greater then 0 for every valid iterator.
213  /// Invalid iterator (with null Scope) has VarIter equal to 0.
214  unsigned VarIter = 0;
215 
216  public:
217  /// Create invalid iterator. Dereferencing invalid iterator is not allowed.
218  /// Incrementing invalid iterator is allowed and will result in invalid
219  /// iterator.
220  const_iterator() = default;
221 
222  /// Create valid iterator. In case when S.Prev is an invalid iterator and
223  /// I is equal to 0, this will create invalid iterator.
224  const_iterator(const LocalScope& S, unsigned I)
225  : Scope(&S), VarIter(I) {
226  // Iterator to "end" of scope is not allowed. Handle it by going up
227  // in scopes tree possibly up to invalid iterator in the root.
228  if (VarIter == 0 && Scope)
229  *this = Scope->Prev;
230  }
231 
232  VarDecl *const* operator->() const {
233  assert(Scope && "Dereferencing invalid iterator is not allowed");
234  assert(VarIter != 0 && "Iterator has invalid value of VarIter member");
235  return &Scope->Vars[VarIter - 1];
236  }
237 
238  const VarDecl *getFirstVarInScope() const {
239  assert(Scope && "Dereferencing invalid iterator is not allowed");
240  assert(VarIter != 0 && "Iterator has invalid value of VarIter member");
241  return Scope->Vars[0];
242  }
243 
244  VarDecl *operator*() const {
245  return *this->operator->();
246  }
247 
248  const_iterator &operator++() {
249  if (!Scope)
250  return *this;
251 
252  assert(VarIter != 0 && "Iterator has invalid value of VarIter member");
253  --VarIter;
254  if (VarIter == 0)
255  *this = Scope->Prev;
256  return *this;
257  }
258  const_iterator operator++(int) {
259  const_iterator P = *this;
260  ++*this;
261  return P;
262  }
263 
264  bool operator==(const const_iterator &rhs) const {
265  return Scope == rhs.Scope && VarIter == rhs.VarIter;
266  }
267  bool operator!=(const const_iterator &rhs) const {
268  return !(*this == rhs);
269  }
270 
271  explicit operator bool() const {
272  return *this != const_iterator();
273  }
274 
275  int distance(const_iterator L);
276  const_iterator shared_parent(const_iterator L);
277  bool pointsToFirstDeclaredVar() { return VarIter == 1; }
278  };
279 
280 private:
281  BumpVectorContext ctx;
282 
283  /// Automatic variables in order of declaration.
284  AutomaticVarsTy Vars;
285 
286  /// Iterator to variable in previous scope that was declared just before
287  /// begin of this scope.
288  const_iterator Prev;
289 
290 public:
291  /// Constructs empty scope linked to previous scope in specified place.
292  LocalScope(BumpVectorContext ctx, const_iterator P)
293  : ctx(std::move(ctx)), Vars(this->ctx, 4), Prev(P) {}
294 
295  /// Begin of scope in direction of CFG building (backwards).
296  const_iterator begin() const { return const_iterator(*this, Vars.size()); }
297 
298  void addVar(VarDecl *VD) {
299  Vars.push_back(VD, ctx);
300  }
301 };
302 
303 } // namespace
304 
305 /// distance - Calculates distance from this to L. L must be reachable from this
306 /// (with use of ++ operator). Cost of calculating the distance is linear w.r.t.
307 /// number of scopes between this and L.
308 int LocalScope::const_iterator::distance(LocalScope::const_iterator L) {
309  int D = 0;
310  const_iterator F = *this;
311  while (F.Scope != L.Scope) {
312  assert(F != const_iterator() &&
313  "L iterator is not reachable from F iterator.");
314  D += F.VarIter;
315  F = F.Scope->Prev;
316  }
317  D += F.VarIter - L.VarIter;
318  return D;
319 }
320 
321 /// Calculates the closest parent of this iterator
322 /// that is in a scope reachable through the parents of L.
323 /// I.e. when using 'goto' from this to L, the lifetime of all variables
324 /// between this and shared_parent(L) end.
325 LocalScope::const_iterator
326 LocalScope::const_iterator::shared_parent(LocalScope::const_iterator L) {
327  llvm::SmallPtrSet<const LocalScope *, 4> ScopesOfL;
328  while (true) {
329  ScopesOfL.insert(L.Scope);
330  if (L == const_iterator())
331  break;
332  L = L.Scope->Prev;
333  }
334 
335  const_iterator F = *this;
336  while (true) {
337  if (ScopesOfL.count(F.Scope))
338  return F;
339  assert(F != const_iterator() &&
340  "L iterator is not reachable from F iterator.");
341  F = F.Scope->Prev;
342  }
343 }
344 
345 namespace {
346 
347 /// Structure for specifying position in CFG during its build process. It
348 /// consists of CFGBlock that specifies position in CFG and
349 /// LocalScope::const_iterator that specifies position in LocalScope graph.
350 struct BlockScopePosPair {
351  CFGBlock *block = nullptr;
352  LocalScope::const_iterator scopePosition;
353 
354  BlockScopePosPair() = default;
355  BlockScopePosPair(CFGBlock *b, LocalScope::const_iterator scopePos)
356  : block(b), scopePosition(scopePos) {}
357 };
358 
359 /// TryResult - a class representing a variant over the values
360 /// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool,
361 /// and is used by the CFGBuilder to decide if a branch condition
362 /// can be decided up front during CFG construction.
363 class TryResult {
364  int X = -1;
365 
366 public:
367  TryResult() = default;
368  TryResult(bool b) : X(b ? 1 : 0) {}
369 
370  bool isTrue() const { return X == 1; }
371  bool isFalse() const { return X == 0; }
372  bool isKnown() const { return X >= 0; }
373 
374  void negate() {
375  assert(isKnown());
376  X ^= 0x1;
377  }
378 };
379 
380 } // namespace
381 
382 static TryResult bothKnownTrue(TryResult R1, TryResult R2) {
383  if (!R1.isKnown() || !R2.isKnown())
384  return TryResult();
385  return TryResult(R1.isTrue() && R2.isTrue());
386 }
387 
388 namespace {
389 
390 class reverse_children {
391  llvm::SmallVector<Stmt *, 12> childrenBuf;
393 
394 public:
395  reverse_children(Stmt *S);
396 
397  using iterator = ArrayRef<Stmt *>::reverse_iterator;
398 
399  iterator begin() const { return children.rbegin(); }
400  iterator end() const { return children.rend(); }
401 };
402 
403 } // namespace
404 
405 reverse_children::reverse_children(Stmt *S) {
406  if (CallExpr *CE = dyn_cast<CallExpr>(S)) {
407  children = CE->getRawSubExprs();
408  return;
409  }
410  switch (S->getStmtClass()) {
411  // Note: Fill in this switch with more cases we want to optimize.
412  case Stmt::InitListExprClass: {
413  InitListExpr *IE = cast<InitListExpr>(S);
414  children = llvm::makeArrayRef(reinterpret_cast<Stmt**>(IE->getInits()),
415  IE->getNumInits());
416  return;
417  }
418  default:
419  break;
420  }
421 
422  // Default case for all other statements.
423  for (Stmt *SubStmt : S->children())
424  childrenBuf.push_back(SubStmt);
425 
426  // This needs to be done *after* childrenBuf has been populated.
427  children = childrenBuf;
428 }
429 
430 namespace {
431 
432 /// CFGBuilder - This class implements CFG construction from an AST.
433 /// The builder is stateful: an instance of the builder should be used to only
434 /// construct a single CFG.
435 ///
436 /// Example usage:
437 ///
438 /// CFGBuilder builder;
439 /// std::unique_ptr<CFG> cfg = builder.buildCFG(decl, stmt1);
440 ///
441 /// CFG construction is done via a recursive walk of an AST. We actually parse
442 /// the AST in reverse order so that the successor of a basic block is
443 /// constructed prior to its predecessor. This allows us to nicely capture
444 /// implicit fall-throughs without extra basic blocks.
445 class CFGBuilder {
446  using JumpTarget = BlockScopePosPair;
447  using JumpSource = BlockScopePosPair;
448 
449  ASTContext *Context;
450  std::unique_ptr<CFG> cfg;
451 
452  // Current block.
453  CFGBlock *Block = nullptr;
454 
455  // Block after the current block.
456  CFGBlock *Succ = nullptr;
457 
458  JumpTarget ContinueJumpTarget;
459  JumpTarget BreakJumpTarget;
460  JumpTarget SEHLeaveJumpTarget;
461  CFGBlock *SwitchTerminatedBlock = nullptr;
462  CFGBlock *DefaultCaseBlock = nullptr;
463 
464  // This can point either to a try or a __try block. The frontend forbids
465  // mixing both kinds in one function, so having one for both is enough.
466  CFGBlock *TryTerminatedBlock = nullptr;
467 
468  // Current position in local scope.
469  LocalScope::const_iterator ScopePos;
470 
471  // LabelMap records the mapping from Label expressions to their jump targets.
472  using LabelMapTy = llvm::DenseMap<LabelDecl *, JumpTarget>;
473  LabelMapTy LabelMap;
474 
475  // A list of blocks that end with a "goto" that must be backpatched to their
476  // resolved targets upon completion of CFG construction.
477  using BackpatchBlocksTy = std::vector<JumpSource>;
478  BackpatchBlocksTy BackpatchBlocks;
479 
480  // A list of labels whose address has been taken (for indirect gotos).
481  using LabelSetTy = llvm::SmallSetVector<LabelDecl *, 8>;
482  LabelSetTy AddressTakenLabels;
483 
484  // Information about the currently visited C++ object construction site.
485  // This is set in the construction trigger and read when the constructor
486  // or a function that returns an object by value is being visited.
487  llvm::DenseMap<Expr *, const ConstructionContextLayer *>
488  ConstructionContextMap;
489 
490  using DeclsWithEndedScopeSetTy = llvm::SmallSetVector<VarDecl *, 16>;
491  DeclsWithEndedScopeSetTy DeclsWithEndedScope;
492 
493  bool badCFG = false;
494  const CFG::BuildOptions &BuildOpts;
495 
496  // State to track for building switch statements.
497  bool switchExclusivelyCovered = false;
498  Expr::EvalResult *switchCond = nullptr;
499 
500  CFG::BuildOptions::ForcedBlkExprs::value_type *cachedEntry = nullptr;
501  const Stmt *lastLookup = nullptr;
502 
503  // Caches boolean evaluations of expressions to avoid multiple re-evaluations
504  // during construction of branches for chained logical operators.
505  using CachedBoolEvalsTy = llvm::DenseMap<Expr *, TryResult>;
506  CachedBoolEvalsTy CachedBoolEvals;
507 
508 public:
509  explicit CFGBuilder(ASTContext *astContext,
510  const CFG::BuildOptions &buildOpts)
511  : Context(astContext), cfg(new CFG()), // crew a new CFG
512  ConstructionContextMap(), BuildOpts(buildOpts) {}
513 
514 
515  // buildCFG - Used by external clients to construct the CFG.
516  std::unique_ptr<CFG> buildCFG(const Decl *D, Stmt *Statement);
517 
518  bool alwaysAdd(const Stmt *stmt);
519 
520 private:
521  // Visitors to walk an AST and construct the CFG.
522  CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc);
523  CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc);
524  CFGBlock *VisitBreakStmt(BreakStmt *B);
525  CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc);
526  CFGBlock *VisitCaseStmt(CaseStmt *C);
527  CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc);
528  CFGBlock *VisitCompoundStmt(CompoundStmt *C);
529  CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C,
530  AddStmtChoice asc);
531  CFGBlock *VisitContinueStmt(ContinueStmt *C);
532  CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
533  AddStmtChoice asc);
534  CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S);
535  CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc);
536  CFGBlock *VisitCXXNewExpr(CXXNewExpr *DE, AddStmtChoice asc);
537  CFGBlock *VisitCXXDeleteExpr(CXXDeleteExpr *DE, AddStmtChoice asc);
538  CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S);
539  CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
540  AddStmtChoice asc);
541  CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
542  AddStmtChoice asc);
543  CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T);
544  CFGBlock *VisitCXXTryStmt(CXXTryStmt *S);
545  CFGBlock *VisitDeclStmt(DeclStmt *DS);
546  CFGBlock *VisitDeclSubExpr(DeclStmt *DS);
547  CFGBlock *VisitDefaultStmt(DefaultStmt *D);
548  CFGBlock *VisitDoStmt(DoStmt *D);
549  CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, AddStmtChoice asc);
550  CFGBlock *VisitForStmt(ForStmt *F);
551  CFGBlock *VisitGotoStmt(GotoStmt *G);
552  CFGBlock *VisitGCCAsmStmt(GCCAsmStmt *G, AddStmtChoice asc);
553  CFGBlock *VisitIfStmt(IfStmt *I);
554  CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc);
555  CFGBlock *VisitConstantExpr(ConstantExpr *E, AddStmtChoice asc);
556  CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I);
557  CFGBlock *VisitLabelStmt(LabelStmt *L);
558  CFGBlock *VisitBlockExpr(BlockExpr *E, AddStmtChoice asc);
559  CFGBlock *VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc);
560  CFGBlock *VisitLogicalOperator(BinaryOperator *B);
561  std::pair<CFGBlock *, CFGBlock *> VisitLogicalOperator(BinaryOperator *B,
562  Stmt *Term,
563  CFGBlock *TrueBlock,
564  CFGBlock *FalseBlock);
565  CFGBlock *VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *MTE,
566  AddStmtChoice asc);
567  CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc);
568  CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S);
569  CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S);
570  CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S);
571  CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S);
572  CFGBlock *VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S);
573  CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S);
574  CFGBlock *VisitObjCMessageExpr(ObjCMessageExpr *E, AddStmtChoice asc);
575  CFGBlock *VisitPseudoObjectExpr(PseudoObjectExpr *E);
576  CFGBlock *VisitReturnStmt(Stmt *S);
577  CFGBlock *VisitSEHExceptStmt(SEHExceptStmt *S);
578  CFGBlock *VisitSEHFinallyStmt(SEHFinallyStmt *S);
579  CFGBlock *VisitSEHLeaveStmt(SEHLeaveStmt *S);
580  CFGBlock *VisitSEHTryStmt(SEHTryStmt *S);
581  CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc);
582  CFGBlock *VisitSwitchStmt(SwitchStmt *S);
583  CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
584  AddStmtChoice asc);
585  CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc);
586  CFGBlock *VisitWhileStmt(WhileStmt *W);
587 
588  CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd);
589  CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc);
590  CFGBlock *VisitChildren(Stmt *S);
591  CFGBlock *VisitNoRecurse(Expr *E, AddStmtChoice asc);
592 
593  void maybeAddScopeBeginForVarDecl(CFGBlock *B, const VarDecl *VD,
594  const Stmt *S) {
595  if (ScopePos && (VD == ScopePos.getFirstVarInScope()))
596  appendScopeBegin(B, VD, S);
597  }
598 
599  /// When creating the CFG for temporary destructors, we want to mirror the
600  /// branch structure of the corresponding constructor calls.
601  /// Thus, while visiting a statement for temporary destructors, we keep a
602  /// context to keep track of the following information:
603  /// - whether a subexpression is executed unconditionally
604  /// - if a subexpression is executed conditionally, the first
605  /// CXXBindTemporaryExpr we encounter in that subexpression (which
606  /// corresponds to the last temporary destructor we have to call for this
607  /// subexpression) and the CFG block at that point (which will become the
608  /// successor block when inserting the decision point).
609  ///
610  /// That way, we can build the branch structure for temporary destructors as
611  /// follows:
612  /// 1. If a subexpression is executed unconditionally, we add the temporary
613  /// destructor calls to the current block.
614  /// 2. If a subexpression is executed conditionally, when we encounter a
615  /// CXXBindTemporaryExpr:
616  /// a) If it is the first temporary destructor call in the subexpression,
617  /// we remember the CXXBindTemporaryExpr and the current block in the
618  /// TempDtorContext; we start a new block, and insert the temporary
619  /// destructor call.
620  /// b) Otherwise, add the temporary destructor call to the current block.
621  /// 3. When we finished visiting a conditionally executed subexpression,
622  /// and we found at least one temporary constructor during the visitation
623  /// (2.a has executed), we insert a decision block that uses the
624  /// CXXBindTemporaryExpr as terminator, and branches to the current block
625  /// if the CXXBindTemporaryExpr was marked executed, and otherwise
626  /// branches to the stored successor.
627  struct TempDtorContext {
628  TempDtorContext() = default;
629  TempDtorContext(TryResult KnownExecuted)
630  : IsConditional(true), KnownExecuted(KnownExecuted) {}
631 
632  /// Returns whether we need to start a new branch for a temporary destructor
633  /// call. This is the case when the temporary destructor is
634  /// conditionally executed, and it is the first one we encounter while
635  /// visiting a subexpression - other temporary destructors at the same level
636  /// will be added to the same block and are executed under the same
637  /// condition.
638  bool needsTempDtorBranch() const {
639  return IsConditional && !TerminatorExpr;
640  }
641 
642  /// Remember the successor S of a temporary destructor decision branch for
643  /// the corresponding CXXBindTemporaryExpr E.
644  void setDecisionPoint(CFGBlock *S, CXXBindTemporaryExpr *E) {
645  Succ = S;
646  TerminatorExpr = E;
647  }
648 
649  const bool IsConditional = false;
650  const TryResult KnownExecuted = true;
651  CFGBlock *Succ = nullptr;
652  CXXBindTemporaryExpr *TerminatorExpr = nullptr;
653  };
654 
655  // Visitors to walk an AST and generate destructors of temporaries in
656  // full expression.
657  CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary,
658  TempDtorContext &Context);
659  CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E, TempDtorContext &Context);
660  CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E,
661  TempDtorContext &Context);
662  CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(
663  CXXBindTemporaryExpr *E, bool BindToTemporary, TempDtorContext &Context);
664  CFGBlock *VisitConditionalOperatorForTemporaryDtors(
665  AbstractConditionalOperator *E, bool BindToTemporary,
666  TempDtorContext &Context);
667  void InsertTempDtorDecisionBlock(const TempDtorContext &Context,
668  CFGBlock *FalseSucc = nullptr);
669 
670  // NYS == Not Yet Supported
671  CFGBlock *NYS() {
672  badCFG = true;
673  return Block;
674  }
675 
676  // Remember to apply the construction context based on the current \p Layer
677  // when constructing the CFG element for \p CE.
678  void consumeConstructionContext(const ConstructionContextLayer *Layer,
679  Expr *E);
680 
681  // Scan \p Child statement to find constructors in it, while keeping in mind
682  // that its parent statement is providing a partial construction context
683  // described by \p Layer. If a constructor is found, it would be assigned
684  // the context based on the layer. If an additional construction context layer
685  // is found, the function recurses into that.
686  void findConstructionContexts(const ConstructionContextLayer *Layer,
687  Stmt *Child);
688 
689  // Scan all arguments of a call expression for a construction context.
690  // These sorts of call expressions don't have a common superclass,
691  // hence strict duck-typing.
692  template <typename CallLikeExpr,
693  typename = typename std::enable_if<
694  std::is_same<CallLikeExpr, CallExpr>::value ||
695  std::is_same<CallLikeExpr, CXXConstructExpr>::value ||
696  std::is_same<CallLikeExpr, ObjCMessageExpr>::value>>
697  void findConstructionContextsForArguments(CallLikeExpr *E) {
698  for (unsigned i = 0, e = E->getNumArgs(); i != e; ++i) {
699  Expr *Arg = E->getArg(i);
700  if (Arg->getType()->getAsCXXRecordDecl() && !Arg->isGLValue())
701  findConstructionContexts(
702  ConstructionContextLayer::create(cfg->getBumpVectorContext(),
704  Arg);
705  }
706  }
707 
708  // Unset the construction context after consuming it. This is done immediately
709  // after adding the CFGConstructor or CFGCXXRecordTypedCall element, so
710  // there's no need to do this manually in every Visit... function.
711  void cleanupConstructionContext(Expr *E);
712 
713  void autoCreateBlock() { if (!Block) Block = createBlock(); }
714  CFGBlock *createBlock(bool add_successor = true);
715  CFGBlock *createNoReturnBlock();
716 
717  CFGBlock *addStmt(Stmt *S) {
718  return Visit(S, AddStmtChoice::AlwaysAdd);
719  }
720 
721  CFGBlock *addInitializer(CXXCtorInitializer *I);
722  void addLoopExit(const Stmt *LoopStmt);
723  void addAutomaticObjDtors(LocalScope::const_iterator B,
724  LocalScope::const_iterator E, Stmt *S);
725  void addLifetimeEnds(LocalScope::const_iterator B,
726  LocalScope::const_iterator E, Stmt *S);
727  void addAutomaticObjHandling(LocalScope::const_iterator B,
728  LocalScope::const_iterator E, Stmt *S);
729  void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD);
730  void addScopesEnd(LocalScope::const_iterator B, LocalScope::const_iterator E,
731  Stmt *S);
732 
733  void getDeclsWithEndedScope(LocalScope::const_iterator B,
734  LocalScope::const_iterator E, Stmt *S);
735 
736  // Local scopes creation.
737  LocalScope* createOrReuseLocalScope(LocalScope* Scope);
738 
739  void addLocalScopeForStmt(Stmt *S);
740  LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS,
741  LocalScope* Scope = nullptr);
742  LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = nullptr);
743 
744  void addLocalScopeAndDtors(Stmt *S);
745 
746  const ConstructionContext *retrieveAndCleanupConstructionContext(Expr *E) {
747  if (!BuildOpts.AddRichCXXConstructors)
748  return nullptr;
749 
750  const ConstructionContextLayer *Layer = ConstructionContextMap.lookup(E);
751  if (!Layer)
752  return nullptr;
753 
754  cleanupConstructionContext(E);
755  return ConstructionContext::createFromLayers(cfg->getBumpVectorContext(),
756  Layer);
757  }
758 
759  // Interface to CFGBlock - adding CFGElements.
760 
761  void appendStmt(CFGBlock *B, const Stmt *S) {
762  if (alwaysAdd(S) && cachedEntry)
763  cachedEntry->second = B;
764 
765  // All block-level expressions should have already been IgnoreParens()ed.
766  assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S);
767  B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext());
768  }
769 
770  void appendConstructor(CFGBlock *B, CXXConstructExpr *CE) {
771  if (const ConstructionContext *CC =
772  retrieveAndCleanupConstructionContext(CE)) {
773  B->appendConstructor(CE, CC, cfg->getBumpVectorContext());
774  return;
775  }
776 
777  // No valid construction context found. Fall back to statement.
778  B->appendStmt(CE, cfg->getBumpVectorContext());
779  }
780 
781  void appendCall(CFGBlock *B, CallExpr *CE) {
782  if (alwaysAdd(CE) && cachedEntry)
783  cachedEntry->second = B;
784 
785  if (const ConstructionContext *CC =
786  retrieveAndCleanupConstructionContext(CE)) {
787  B->appendCXXRecordTypedCall(CE, CC, cfg->getBumpVectorContext());
788  return;
789  }
790 
791  // No valid construction context found. Fall back to statement.
792  B->appendStmt(CE, cfg->getBumpVectorContext());
793  }
794 
795  void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) {
796  B->appendInitializer(I, cfg->getBumpVectorContext());
797  }
798 
799  void appendNewAllocator(CFGBlock *B, CXXNewExpr *NE) {
800  B->appendNewAllocator(NE, cfg->getBumpVectorContext());
801  }
802 
803  void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) {
804  B->appendBaseDtor(BS, cfg->getBumpVectorContext());
805  }
806 
807  void appendMemberDtor(CFGBlock *B, FieldDecl *FD) {
808  B->appendMemberDtor(FD, cfg->getBumpVectorContext());
809  }
810 
811  void appendObjCMessage(CFGBlock *B, ObjCMessageExpr *ME) {
812  if (alwaysAdd(ME) && cachedEntry)
813  cachedEntry->second = B;
814 
815  if (const ConstructionContext *CC =
816  retrieveAndCleanupConstructionContext(ME)) {
817  B->appendCXXRecordTypedCall(ME, CC, cfg->getBumpVectorContext());
818  return;
819  }
820 
821  B->appendStmt(const_cast<ObjCMessageExpr *>(ME),
822  cfg->getBumpVectorContext());
823  }
824 
825  void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) {
826  B->appendTemporaryDtor(E, cfg->getBumpVectorContext());
827  }
828 
829  void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) {
830  B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext());
831  }
832 
833  void appendLifetimeEnds(CFGBlock *B, VarDecl *VD, Stmt *S) {
834  B->appendLifetimeEnds(VD, S, cfg->getBumpVectorContext());
835  }
836 
837  void appendLoopExit(CFGBlock *B, const Stmt *LoopStmt) {
838  B->appendLoopExit(LoopStmt, cfg->getBumpVectorContext());
839  }
840 
841  void appendDeleteDtor(CFGBlock *B, CXXRecordDecl *RD, CXXDeleteExpr *DE) {
842  B->appendDeleteDtor(RD, DE, cfg->getBumpVectorContext());
843  }
844 
845  void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
846  LocalScope::const_iterator B, LocalScope::const_iterator E);
847 
848  void prependAutomaticObjLifetimeWithTerminator(CFGBlock *Blk,
849  LocalScope::const_iterator B,
850  LocalScope::const_iterator E);
851 
852  const VarDecl *
853  prependAutomaticObjScopeEndWithTerminator(CFGBlock *Blk,
854  LocalScope::const_iterator B,
855  LocalScope::const_iterator E);
856 
857  void addSuccessor(CFGBlock *B, CFGBlock *S, bool IsReachable = true) {
858  B->addSuccessor(CFGBlock::AdjacentBlock(S, IsReachable),
859  cfg->getBumpVectorContext());
860  }
861 
862  /// Add a reachable successor to a block, with the alternate variant that is
863  /// unreachable.
864  void addSuccessor(CFGBlock *B, CFGBlock *ReachableBlock, CFGBlock *AltBlock) {
865  B->addSuccessor(CFGBlock::AdjacentBlock(ReachableBlock, AltBlock),
866  cfg->getBumpVectorContext());
867  }
868 
869  void appendScopeBegin(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
870  if (BuildOpts.AddScopes)
871  B->appendScopeBegin(VD, S, cfg->getBumpVectorContext());
872  }
873 
874  void prependScopeBegin(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
875  if (BuildOpts.AddScopes)
876  B->prependScopeBegin(VD, S, cfg->getBumpVectorContext());
877  }
878 
879  void appendScopeEnd(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
880  if (BuildOpts.AddScopes)
881  B->appendScopeEnd(VD, S, cfg->getBumpVectorContext());
882  }
883 
884  void prependScopeEnd(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
885  if (BuildOpts.AddScopes)
886  B->prependScopeEnd(VD, S, cfg->getBumpVectorContext());
887  }
888 
889  /// Find a relational comparison with an expression evaluating to a
890  /// boolean and a constant other than 0 and 1.
891  /// e.g. if ((x < y) == 10)
892  TryResult checkIncorrectRelationalOperator(const BinaryOperator *B) {
893  const Expr *LHSExpr = B->getLHS()->IgnoreParens();
894  const Expr *RHSExpr = B->getRHS()->IgnoreParens();
895 
896  const IntegerLiteral *IntLiteral = dyn_cast<IntegerLiteral>(LHSExpr);
897  const Expr *BoolExpr = RHSExpr;
898  bool IntFirst = true;
899  if (!IntLiteral) {
900  IntLiteral = dyn_cast<IntegerLiteral>(RHSExpr);
901  BoolExpr = LHSExpr;
902  IntFirst = false;
903  }
904 
905  if (!IntLiteral || !BoolExpr->isKnownToHaveBooleanValue())
906  return TryResult();
907 
908  llvm::APInt IntValue = IntLiteral->getValue();
909  if ((IntValue == 1) || (IntValue == 0))
910  return TryResult();
911 
912  bool IntLarger = IntLiteral->getType()->isUnsignedIntegerType() ||
913  !IntValue.isNegative();
914 
915  BinaryOperatorKind Bok = B->getOpcode();
916  if (Bok == BO_GT || Bok == BO_GE) {
917  // Always true for 10 > bool and bool > -1
918  // Always false for -1 > bool and bool > 10
919  return TryResult(IntFirst == IntLarger);
920  } else {
921  // Always true for -1 < bool and bool < 10
922  // Always false for 10 < bool and bool < -1
923  return TryResult(IntFirst != IntLarger);
924  }
925  }
926 
927  /// Find an incorrect equality comparison. Either with an expression
928  /// evaluating to a boolean and a constant other than 0 and 1.
929  /// e.g. if (!x == 10) or a bitwise and/or operation that always evaluates to
930  /// true/false e.q. (x & 8) == 4.
931  TryResult checkIncorrectEqualityOperator(const BinaryOperator *B) {
932  const Expr *LHSExpr = B->getLHS()->IgnoreParens();
933  const Expr *RHSExpr = B->getRHS()->IgnoreParens();
934 
935  const IntegerLiteral *IntLiteral = dyn_cast<IntegerLiteral>(LHSExpr);
936  const Expr *BoolExpr = RHSExpr;
937 
938  if (!IntLiteral) {
939  IntLiteral = dyn_cast<IntegerLiteral>(RHSExpr);
940  BoolExpr = LHSExpr;
941  }
942 
943  if (!IntLiteral)
944  return TryResult();
945 
946  const BinaryOperator *BitOp = dyn_cast<BinaryOperator>(BoolExpr);
947  if (BitOp && (BitOp->getOpcode() == BO_And ||
948  BitOp->getOpcode() == BO_Or)) {
949  const Expr *LHSExpr2 = BitOp->getLHS()->IgnoreParens();
950  const Expr *RHSExpr2 = BitOp->getRHS()->IgnoreParens();
951 
952  const IntegerLiteral *IntLiteral2 = dyn_cast<IntegerLiteral>(LHSExpr2);
953 
954  if (!IntLiteral2)
955  IntLiteral2 = dyn_cast<IntegerLiteral>(RHSExpr2);
956 
957  if (!IntLiteral2)
958  return TryResult();
959 
960  llvm::APInt L1 = IntLiteral->getValue();
961  llvm::APInt L2 = IntLiteral2->getValue();
962  if ((BitOp->getOpcode() == BO_And && (L2 & L1) != L1) ||
963  (BitOp->getOpcode() == BO_Or && (L2 | L1) != L1)) {
964  if (BuildOpts.Observer)
965  BuildOpts.Observer->compareBitwiseEquality(B,
966  B->getOpcode() != BO_EQ);
967  TryResult(B->getOpcode() != BO_EQ);
968  }
969  } else if (BoolExpr->isKnownToHaveBooleanValue()) {
970  llvm::APInt IntValue = IntLiteral->getValue();
971  if ((IntValue == 1) || (IntValue == 0)) {
972  return TryResult();
973  }
974  return TryResult(B->getOpcode() != BO_EQ);
975  }
976 
977  return TryResult();
978  }
979 
980  TryResult analyzeLogicOperatorCondition(BinaryOperatorKind Relation,
981  const llvm::APSInt &Value1,
982  const llvm::APSInt &Value2) {
983  assert(Value1.isSigned() == Value2.isSigned());
984  switch (Relation) {
985  default:
986  return TryResult();
987  case BO_EQ:
988  return TryResult(Value1 == Value2);
989  case BO_NE:
990  return TryResult(Value1 != Value2);
991  case BO_LT:
992  return TryResult(Value1 < Value2);
993  case BO_LE:
994  return TryResult(Value1 <= Value2);
995  case BO_GT:
996  return TryResult(Value1 > Value2);
997  case BO_GE:
998  return TryResult(Value1 >= Value2);
999  }
1000  }
1001 
1002  /// Find a pair of comparison expressions with or without parentheses
1003  /// with a shared variable and constants and a logical operator between them
1004  /// that always evaluates to either true or false.
1005  /// e.g. if (x != 3 || x != 4)
1006  TryResult checkIncorrectLogicOperator(const BinaryOperator *B) {
1007  assert(B->isLogicalOp());
1008  const BinaryOperator *LHS =
1009  dyn_cast<BinaryOperator>(B->getLHS()->IgnoreParens());
1010  const BinaryOperator *RHS =
1011  dyn_cast<BinaryOperator>(B->getRHS()->IgnoreParens());
1012  if (!LHS || !RHS)
1013  return {};
1014 
1015  if (!LHS->isComparisonOp() || !RHS->isComparisonOp())
1016  return {};
1017 
1018  const DeclRefExpr *Decl1;
1019  const Expr *Expr1;
1020  BinaryOperatorKind BO1;
1021  std::tie(Decl1, BO1, Expr1) = tryNormalizeBinaryOperator(LHS);
1022 
1023  if (!Decl1 || !Expr1)
1024  return {};
1025 
1026  const DeclRefExpr *Decl2;
1027  const Expr *Expr2;
1028  BinaryOperatorKind BO2;
1029  std::tie(Decl2, BO2, Expr2) = tryNormalizeBinaryOperator(RHS);
1030 
1031  if (!Decl2 || !Expr2)
1032  return {};
1033 
1034  // Check that it is the same variable on both sides.
1035  if (Decl1->getDecl() != Decl2->getDecl())
1036  return {};
1037 
1038  // Make sure the user's intent is clear (e.g. they're comparing against two
1039  // int literals, or two things from the same enum)
1040  if (!areExprTypesCompatible(Expr1, Expr2))
1041  return {};
1042 
1043  Expr::EvalResult L1Result, L2Result;
1044  if (!Expr1->EvaluateAsInt(L1Result, *Context) ||
1045  !Expr2->EvaluateAsInt(L2Result, *Context))
1046  return {};
1047 
1048  llvm::APSInt L1 = L1Result.Val.getInt();
1049  llvm::APSInt L2 = L2Result.Val.getInt();
1050 
1051  // Can't compare signed with unsigned or with different bit width.
1052  if (L1.isSigned() != L2.isSigned() || L1.getBitWidth() != L2.getBitWidth())
1053  return {};
1054 
1055  // Values that will be used to determine if result of logical
1056  // operator is always true/false
1057  const llvm::APSInt Values[] = {
1058  // Value less than both Value1 and Value2
1059  llvm::APSInt::getMinValue(L1.getBitWidth(), L1.isUnsigned()),
1060  // L1
1061  L1,
1062  // Value between Value1 and Value2
1063  ((L1 < L2) ? L1 : L2) + llvm::APSInt(llvm::APInt(L1.getBitWidth(), 1),
1064  L1.isUnsigned()),
1065  // L2
1066  L2,
1067  // Value greater than both Value1 and Value2
1068  llvm::APSInt::getMaxValue(L1.getBitWidth(), L1.isUnsigned()),
1069  };
1070 
1071  // Check whether expression is always true/false by evaluating the following
1072  // * variable x is less than the smallest literal.
1073  // * variable x is equal to the smallest literal.
1074  // * Variable x is between smallest and largest literal.
1075  // * Variable x is equal to the largest literal.
1076  // * Variable x is greater than largest literal.
1077  bool AlwaysTrue = true, AlwaysFalse = true;
1078  for (const llvm::APSInt &Value : Values) {
1079  TryResult Res1, Res2;
1080  Res1 = analyzeLogicOperatorCondition(BO1, Value, L1);
1081  Res2 = analyzeLogicOperatorCondition(BO2, Value, L2);
1082 
1083  if (!Res1.isKnown() || !Res2.isKnown())
1084  return {};
1085 
1086  if (B->getOpcode() == BO_LAnd) {
1087  AlwaysTrue &= (Res1.isTrue() && Res2.isTrue());
1088  AlwaysFalse &= !(Res1.isTrue() && Res2.isTrue());
1089  } else {
1090  AlwaysTrue &= (Res1.isTrue() || Res2.isTrue());
1091  AlwaysFalse &= !(Res1.isTrue() || Res2.isTrue());
1092  }
1093  }
1094 
1095  if (AlwaysTrue || AlwaysFalse) {
1096  if (BuildOpts.Observer)
1097  BuildOpts.Observer->compareAlwaysTrue(B, AlwaysTrue);
1098  return TryResult(AlwaysTrue);
1099  }
1100  return {};
1101  }
1102 
1103  /// Try and evaluate an expression to an integer constant.
1104  bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) {
1105  if (!BuildOpts.PruneTriviallyFalseEdges)
1106  return false;
1107  return !S->isTypeDependent() &&
1108  !S->isValueDependent() &&
1109  S->EvaluateAsRValue(outResult, *Context);
1110  }
1111 
1112  /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1
1113  /// if we can evaluate to a known value, otherwise return -1.
1114  TryResult tryEvaluateBool(Expr *S) {
1115  if (!BuildOpts.PruneTriviallyFalseEdges ||
1116  S->isTypeDependent() || S->isValueDependent())
1117  return {};
1118 
1119  if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(S)) {
1120  if (Bop->isLogicalOp()) {
1121  // Check the cache first.
1122  CachedBoolEvalsTy::iterator I = CachedBoolEvals.find(S);
1123  if (I != CachedBoolEvals.end())
1124  return I->second; // already in map;
1125 
1126  // Retrieve result at first, or the map might be updated.
1127  TryResult Result = evaluateAsBooleanConditionNoCache(S);
1128  CachedBoolEvals[S] = Result; // update or insert
1129  return Result;
1130  }
1131  else {
1132  switch (Bop->getOpcode()) {
1133  default: break;
1134  // For 'x & 0' and 'x * 0', we can determine that
1135  // the value is always false.
1136  case BO_Mul:
1137  case BO_And: {
1138  // If either operand is zero, we know the value
1139  // must be false.
1140  Expr::EvalResult LHSResult;
1141  if (Bop->getLHS()->EvaluateAsInt(LHSResult, *Context)) {
1142  llvm::APSInt IntVal = LHSResult.Val.getInt();
1143  if (!IntVal.getBoolValue()) {
1144  return TryResult(false);
1145  }
1146  }
1147  Expr::EvalResult RHSResult;
1148  if (Bop->getRHS()->EvaluateAsInt(RHSResult, *Context)) {
1149  llvm::APSInt IntVal = RHSResult.Val.getInt();
1150  if (!IntVal.getBoolValue()) {
1151  return TryResult(false);
1152  }
1153  }
1154  }
1155  break;
1156  }
1157  }
1158  }
1159 
1160  return evaluateAsBooleanConditionNoCache(S);
1161  }
1162 
1163  /// Evaluate as boolean \param E without using the cache.
1164  TryResult evaluateAsBooleanConditionNoCache(Expr *E) {
1165  if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(E)) {
1166  if (Bop->isLogicalOp()) {
1167  TryResult LHS = tryEvaluateBool(Bop->getLHS());
1168  if (LHS.isKnown()) {
1169  // We were able to evaluate the LHS, see if we can get away with not
1170  // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
1171  if (LHS.isTrue() == (Bop->getOpcode() == BO_LOr))
1172  return LHS.isTrue();
1173 
1174  TryResult RHS = tryEvaluateBool(Bop->getRHS());
1175  if (RHS.isKnown()) {
1176  if (Bop->getOpcode() == BO_LOr)
1177  return LHS.isTrue() || RHS.isTrue();
1178  else
1179  return LHS.isTrue() && RHS.isTrue();
1180  }
1181  } else {
1182  TryResult RHS = tryEvaluateBool(Bop->getRHS());
1183  if (RHS.isKnown()) {
1184  // We can't evaluate the LHS; however, sometimes the result
1185  // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
1186  if (RHS.isTrue() == (Bop->getOpcode() == BO_LOr))
1187  return RHS.isTrue();
1188  } else {
1189  TryResult BopRes = checkIncorrectLogicOperator(Bop);
1190  if (BopRes.isKnown())
1191  return BopRes.isTrue();
1192  }
1193  }
1194 
1195  return {};
1196  } else if (Bop->isEqualityOp()) {
1197  TryResult BopRes = checkIncorrectEqualityOperator(Bop);
1198  if (BopRes.isKnown())
1199  return BopRes.isTrue();
1200  } else if (Bop->isRelationalOp()) {
1201  TryResult BopRes = checkIncorrectRelationalOperator(Bop);
1202  if (BopRes.isKnown())
1203  return BopRes.isTrue();
1204  }
1205  }
1206 
1207  bool Result;
1208  if (E->EvaluateAsBooleanCondition(Result, *Context))
1209  return Result;
1210 
1211  return {};
1212  }
1213 
1214  bool hasTrivialDestructor(VarDecl *VD);
1215 };
1216 
1217 } // namespace
1218 
1219 inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder,
1220  const Stmt *stmt) const {
1221  return builder.alwaysAdd(stmt) || kind == AlwaysAdd;
1222 }
1223 
1224 bool CFGBuilder::alwaysAdd(const Stmt *stmt) {
1225  bool shouldAdd = BuildOpts.alwaysAdd(stmt);
1226 
1227  if (!BuildOpts.forcedBlkExprs)
1228  return shouldAdd;
1229 
1230  if (lastLookup == stmt) {
1231  if (cachedEntry) {
1232  assert(cachedEntry->first == stmt);
1233  return true;
1234  }
1235  return shouldAdd;
1236  }
1237 
1238  lastLookup = stmt;
1239 
1240  // Perform the lookup!
1241  CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs;
1242 
1243  if (!fb) {
1244  // No need to update 'cachedEntry', since it will always be null.
1245  assert(!cachedEntry);
1246  return shouldAdd;
1247  }
1248 
1249  CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt);
1250  if (itr == fb->end()) {
1251  cachedEntry = nullptr;
1252  return shouldAdd;
1253  }
1254 
1255  cachedEntry = &*itr;
1256  return true;
1257 }
1258 
1259 // FIXME: Add support for dependent-sized array types in C++?
1260 // Does it even make sense to build a CFG for an uninstantiated template?
1261 static const VariableArrayType *FindVA(const Type *t) {
1262  while (const ArrayType *vt = dyn_cast<ArrayType>(t)) {
1263  if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt))
1264  if (vat->getSizeExpr())
1265  return vat;
1266 
1267  t = vt->getElementType().getTypePtr();
1268  }
1269 
1270  return nullptr;
1271 }
1272 
1273 void CFGBuilder::consumeConstructionContext(
1274  const ConstructionContextLayer *Layer, Expr *E) {
1275  assert((isa<CXXConstructExpr>(E) || isa<CallExpr>(E) ||
1276  isa<ObjCMessageExpr>(E)) && "Expression cannot construct an object!");
1277  if (const ConstructionContextLayer *PreviouslyStoredLayer =
1278  ConstructionContextMap.lookup(E)) {
1279  (void)PreviouslyStoredLayer;
1280  // We might have visited this child when we were finding construction
1281  // contexts within its parents.
1282  assert(PreviouslyStoredLayer->isStrictlyMoreSpecificThan(Layer) &&
1283  "Already within a different construction context!");
1284  } else {
1285  ConstructionContextMap[E] = Layer;
1286  }
1287 }
1288 
1289 void CFGBuilder::findConstructionContexts(
1290  const ConstructionContextLayer *Layer, Stmt *Child) {
1291  if (!BuildOpts.AddRichCXXConstructors)
1292  return;
1293 
1294  if (!Child)
1295  return;
1296 
1297  auto withExtraLayer = [this, Layer](const ConstructionContextItem &Item) {
1298  return ConstructionContextLayer::create(cfg->getBumpVectorContext(), Item,
1299  Layer);
1300  };
1301 
1302  switch(Child->getStmtClass()) {
1303  case Stmt::CXXConstructExprClass:
1304  case Stmt::CXXTemporaryObjectExprClass: {
1305  // Support pre-C++17 copy elision AST.
1306  auto *CE = cast<CXXConstructExpr>(Child);
1307  if (BuildOpts.MarkElidedCXXConstructors && CE->isElidable()) {
1308  findConstructionContexts(withExtraLayer(CE), CE->getArg(0));
1309  }
1310 
1311  consumeConstructionContext(Layer, CE);
1312  break;
1313  }
1314  // FIXME: This, like the main visit, doesn't support CUDAKernelCallExpr.
1315  // FIXME: An isa<> would look much better but this whole switch is a
1316  // workaround for an internal compiler error in MSVC 2015 (see r326021).
1317  case Stmt::CallExprClass:
1318  case Stmt::CXXMemberCallExprClass:
1319  case Stmt::CXXOperatorCallExprClass:
1320  case Stmt::UserDefinedLiteralClass:
1321  case Stmt::ObjCMessageExprClass: {
1322  auto *E = cast<Expr>(Child);
1324  consumeConstructionContext(Layer, E);
1325  break;
1326  }
1327  case Stmt::ExprWithCleanupsClass: {
1328  auto *Cleanups = cast<ExprWithCleanups>(Child);
1329  findConstructionContexts(Layer, Cleanups->getSubExpr());
1330  break;
1331  }
1332  case Stmt::CXXFunctionalCastExprClass: {
1333  auto *Cast = cast<CXXFunctionalCastExpr>(Child);
1334  findConstructionContexts(Layer, Cast->getSubExpr());
1335  break;
1336  }
1337  case Stmt::ImplicitCastExprClass: {
1338  auto *Cast = cast<ImplicitCastExpr>(Child);
1339  // Should we support other implicit cast kinds?
1340  switch (Cast->getCastKind()) {
1341  case CK_NoOp:
1342  case CK_ConstructorConversion:
1343  findConstructionContexts(Layer, Cast->getSubExpr());
1344  break;
1345  default:
1346  break;
1347  }
1348  break;
1349  }
1350  case Stmt::CXXBindTemporaryExprClass: {
1351  auto *BTE = cast<CXXBindTemporaryExpr>(Child);
1352  findConstructionContexts(withExtraLayer(BTE), BTE->getSubExpr());
1353  break;
1354  }
1355  case Stmt::MaterializeTemporaryExprClass: {
1356  // Normally we don't want to search in MaterializeTemporaryExpr because
1357  // it indicates the beginning of a temporary object construction context,
1358  // so it shouldn't be found in the middle. However, if it is the beginning
1359  // of an elidable copy or move construction context, we need to include it.
1360  if (Layer->getItem().getKind() ==
1362  auto *MTE = cast<MaterializeTemporaryExpr>(Child);
1363  findConstructionContexts(withExtraLayer(MTE), MTE->GetTemporaryExpr());
1364  }
1365  break;
1366  }
1367  case Stmt::ConditionalOperatorClass: {
1368  auto *CO = cast<ConditionalOperator>(Child);
1369  if (Layer->getItem().getKind() !=
1371  // If the object returned by the conditional operator is not going to be a
1372  // temporary object that needs to be immediately materialized, then
1373  // it must be C++17 with its mandatory copy elision. Do not yet promise
1374  // to support this case.
1375  assert(!CO->getType()->getAsCXXRecordDecl() || CO->isGLValue() ||
1376  Context->getLangOpts().CPlusPlus17);
1377  break;
1378  }
1379  findConstructionContexts(Layer, CO->getLHS());
1380  findConstructionContexts(Layer, CO->getRHS());
1381  break;
1382  }
1383  case Stmt::InitListExprClass: {
1384  auto *ILE = cast<InitListExpr>(Child);
1385  if (ILE->isTransparent()) {
1386  findConstructionContexts(Layer, ILE->getInit(0));
1387  break;
1388  }
1389  // TODO: Handle other cases. For now, fail to find construction contexts.
1390  break;
1391  }
1392  default:
1393  break;
1394  }
1395 }
1396 
1397 void CFGBuilder::cleanupConstructionContext(Expr *E) {
1398  assert(BuildOpts.AddRichCXXConstructors &&
1399  "We should not be managing construction contexts!");
1400  assert(ConstructionContextMap.count(E) &&
1401  "Cannot exit construction context without the context!");
1402  ConstructionContextMap.erase(E);
1403 }
1404 
1405 
1406 /// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an
1407 /// arbitrary statement. Examples include a single expression or a function
1408 /// body (compound statement). The ownership of the returned CFG is
1409 /// transferred to the caller. If CFG construction fails, this method returns
1410 /// NULL.
1411 std::unique_ptr<CFG> CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) {
1412  assert(cfg.get());
1413  if (!Statement)
1414  return nullptr;
1415 
1416  // Create an empty block that will serve as the exit block for the CFG. Since
1417  // this is the first block added to the CFG, it will be implicitly registered
1418  // as the exit block.
1419  Succ = createBlock();
1420  assert(Succ == &cfg->getExit());
1421  Block = nullptr; // the EXIT block is empty. Create all other blocks lazily.
1422 
1423  assert(!(BuildOpts.AddImplicitDtors && BuildOpts.AddLifetime) &&
1424  "AddImplicitDtors and AddLifetime cannot be used at the same time");
1425 
1426  if (BuildOpts.AddImplicitDtors)
1427  if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D))
1428  addImplicitDtorsForDestructor(DD);
1429 
1430  // Visit the statements and create the CFG.
1431  CFGBlock *B = addStmt(Statement);
1432 
1433  if (badCFG)
1434  return nullptr;
1435 
1436  // For C++ constructor add initializers to CFG. Constructors of virtual bases
1437  // are ignored unless the object is of the most derived class.
1438  // class VBase { VBase() = default; VBase(int) {} };
1439  // class A : virtual public VBase { A() : VBase(0) {} };
1440  // class B : public A {};
1441  // B b; // Constructor calls in order: VBase(), A(), B().
1442  // // VBase(0) is ignored because A isn't the most derived class.
1443  // This may result in the virtual base(s) being already initialized at this
1444  // point, in which case we should jump right onto non-virtual bases and
1445  // fields. To handle this, make a CFG branch. We only need to add one such
1446  // branch per constructor, since the Standard states that all virtual bases
1447  // shall be initialized before non-virtual bases and direct data members.
1448  if (const auto *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) {
1449  CFGBlock *VBaseSucc = nullptr;
1450  for (auto *I : llvm::reverse(CD->inits())) {
1451  if (BuildOpts.AddVirtualBaseBranches && !VBaseSucc &&
1452  I->isBaseInitializer() && I->isBaseVirtual()) {
1453  // We've reached the first virtual base init while iterating in reverse
1454  // order. Make a new block for virtual base initializers so that we
1455  // could skip them.
1456  VBaseSucc = Succ = B ? B : &cfg->getExit();
1457  Block = createBlock();
1458  }
1459  B = addInitializer(I);
1460  if (badCFG)
1461  return nullptr;
1462  }
1463  if (VBaseSucc) {
1464  // Make a branch block for potentially skipping virtual base initializers.
1465  Succ = VBaseSucc;
1466  B = createBlock();
1467  B->setTerminator(
1469  addSuccessor(B, Block, true);
1470  }
1471  }
1472 
1473  if (B)
1474  Succ = B;
1475 
1476  // Backpatch the gotos whose label -> block mappings we didn't know when we
1477  // encountered them.
1478  for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(),
1479  E = BackpatchBlocks.end(); I != E; ++I ) {
1480 
1481  CFGBlock *B = I->block;
1482  if (auto *G = dyn_cast<GotoStmt>(B->getTerminator())) {
1483  LabelMapTy::iterator LI = LabelMap.find(G->getLabel());
1484  // If there is no target for the goto, then we are looking at an
1485  // incomplete AST. Handle this by not registering a successor.
1486  if (LI == LabelMap.end())
1487  continue;
1488  JumpTarget JT = LI->second;
1489  prependAutomaticObjLifetimeWithTerminator(B, I->scopePosition,
1490  JT.scopePosition);
1491  prependAutomaticObjDtorsWithTerminator(B, I->scopePosition,
1492  JT.scopePosition);
1493  const VarDecl *VD = prependAutomaticObjScopeEndWithTerminator(
1494  B, I->scopePosition, JT.scopePosition);
1495  appendScopeBegin(JT.block, VD, G);
1496  addSuccessor(B, JT.block);
1497  };
1498  if (auto *G = dyn_cast<GCCAsmStmt>(B->getTerminator())) {
1499  CFGBlock *Successor = (I+1)->block;
1500  for (auto *L : G->labels()) {
1501  LabelMapTy::iterator LI = LabelMap.find(L->getLabel());
1502  // If there is no target for the goto, then we are looking at an
1503  // incomplete AST. Handle this by not registering a successor.
1504  if (LI == LabelMap.end())
1505  continue;
1506  JumpTarget JT = LI->second;
1507  // Successor has been added, so skip it.
1508  if (JT.block == Successor)
1509  continue;
1510  addSuccessor(B, JT.block);
1511  }
1512  I++;
1513  }
1514  }
1515 
1516  // Add successors to the Indirect Goto Dispatch block (if we have one).
1517  if (CFGBlock *B = cfg->getIndirectGotoBlock())
1518  for (LabelSetTy::iterator I = AddressTakenLabels.begin(),
1519  E = AddressTakenLabels.end(); I != E; ++I ) {
1520  // Lookup the target block.
1521  LabelMapTy::iterator LI = LabelMap.find(*I);
1522 
1523  // If there is no target block that contains label, then we are looking
1524  // at an incomplete AST. Handle this by not registering a successor.
1525  if (LI == LabelMap.end()) continue;
1526 
1527  addSuccessor(B, LI->second.block);
1528  }
1529 
1530  // Create an empty entry block that has no predecessors.
1531  cfg->setEntry(createBlock());
1532 
1533  if (BuildOpts.AddRichCXXConstructors)
1534  assert(ConstructionContextMap.empty() &&
1535  "Not all construction contexts were cleaned up!");
1536 
1537  return std::move(cfg);
1538 }
1539 
1540 /// createBlock - Used to lazily create blocks that are connected
1541 /// to the current (global) succcessor.
1542 CFGBlock *CFGBuilder::createBlock(bool add_successor) {
1543  CFGBlock *B = cfg->createBlock();
1544  if (add_successor && Succ)
1545  addSuccessor(B, Succ);
1546  return B;
1547 }
1548 
1549 /// createNoReturnBlock - Used to create a block is a 'noreturn' point in the
1550 /// CFG. It is *not* connected to the current (global) successor, and instead
1551 /// directly tied to the exit block in order to be reachable.
1552 CFGBlock *CFGBuilder::createNoReturnBlock() {
1553  CFGBlock *B = createBlock(false);
1554  B->setHasNoReturnElement();
1555  addSuccessor(B, &cfg->getExit(), Succ);
1556  return B;
1557 }
1558 
1559 /// addInitializer - Add C++ base or member initializer element to CFG.
1560 CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) {
1561  if (!BuildOpts.AddInitializers)
1562  return Block;
1563 
1564  bool HasTemporaries = false;
1565 
1566  // Destructors of temporaries in initialization expression should be called
1567  // after initialization finishes.
1568  Expr *Init = I->getInit();
1569  if (Init) {
1570  HasTemporaries = isa<ExprWithCleanups>(Init);
1571 
1572  if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
1573  // Generate destructors for temporaries in initialization expression.
1574  TempDtorContext Context;
1575  VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
1576  /*BindToTemporary=*/false, Context);
1577  }
1578  }
1579 
1580  autoCreateBlock();
1581  appendInitializer(Block, I);
1582 
1583  if (Init) {
1584  findConstructionContexts(
1585  ConstructionContextLayer::create(cfg->getBumpVectorContext(), I),
1586  Init);
1587 
1588  if (HasTemporaries) {
1589  // For expression with temporaries go directly to subexpression to omit
1590  // generating destructors for the second time.
1591  return Visit(cast<ExprWithCleanups>(Init)->getSubExpr());
1592  }
1593  if (BuildOpts.AddCXXDefaultInitExprInCtors) {
1594  if (CXXDefaultInitExpr *Default = dyn_cast<CXXDefaultInitExpr>(Init)) {
1595  // In general, appending the expression wrapped by a CXXDefaultInitExpr
1596  // may cause the same Expr to appear more than once in the CFG. Doing it
1597  // here is safe because there's only one initializer per field.
1598  autoCreateBlock();
1599  appendStmt(Block, Default);
1600  if (Stmt *Child = Default->getExpr())
1601  if (CFGBlock *R = Visit(Child))
1602  Block = R;
1603  return Block;
1604  }
1605  }
1606  return Visit(Init);
1607  }
1608 
1609  return Block;
1610 }
1611 
1612 /// Retrieve the type of the temporary object whose lifetime was
1613 /// extended by a local reference with the given initializer.
1615  bool *FoundMTE = nullptr) {
1616  while (true) {
1617  // Skip parentheses.
1618  Init = Init->IgnoreParens();
1619 
1620  // Skip through cleanups.
1621  if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Init)) {
1622  Init = EWC->getSubExpr();
1623  continue;
1624  }
1625 
1626  // Skip through the temporary-materialization expression.
1627  if (const MaterializeTemporaryExpr *MTE
1628  = dyn_cast<MaterializeTemporaryExpr>(Init)) {
1629  Init = MTE->GetTemporaryExpr();
1630  if (FoundMTE)
1631  *FoundMTE = true;
1632  continue;
1633  }
1634 
1635  // Skip sub-object accesses into rvalues.
1636  SmallVector<const Expr *, 2> CommaLHSs;
1638  const Expr *SkippedInit =
1639  Init->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
1640  if (SkippedInit != Init) {
1641  Init = SkippedInit;
1642  continue;
1643  }
1644 
1645  break;
1646  }
1647 
1648  return Init->getType();
1649 }
1650 
1651 // TODO: Support adding LoopExit element to the CFG in case where the loop is
1652 // ended by ReturnStmt, GotoStmt or ThrowExpr.
1653 void CFGBuilder::addLoopExit(const Stmt *LoopStmt){
1654  if(!BuildOpts.AddLoopExit)
1655  return;
1656  autoCreateBlock();
1657  appendLoopExit(Block, LoopStmt);
1658 }
1659 
1660 void CFGBuilder::getDeclsWithEndedScope(LocalScope::const_iterator B,
1661  LocalScope::const_iterator E, Stmt *S) {
1662  if (!BuildOpts.AddScopes)
1663  return;
1664 
1665  if (B == E)
1666  return;
1667 
1668  // To go from B to E, one first goes up the scopes from B to P
1669  // then sideways in one scope from P to P' and then down
1670  // the scopes from P' to E.
1671  // The lifetime of all objects between B and P end.
1672  LocalScope::const_iterator P = B.shared_parent(E);
1673  int Dist = B.distance(P);
1674  if (Dist <= 0)
1675  return;
1676 
1677  for (LocalScope::const_iterator I = B; I != P; ++I)
1678  if (I.pointsToFirstDeclaredVar())
1679  DeclsWithEndedScope.insert(*I);
1680 }
1681 
1682 void CFGBuilder::addAutomaticObjHandling(LocalScope::const_iterator B,
1683  LocalScope::const_iterator E,
1684  Stmt *S) {
1685  getDeclsWithEndedScope(B, E, S);
1686  if (BuildOpts.AddScopes)
1687  addScopesEnd(B, E, S);
1688  if (BuildOpts.AddImplicitDtors)
1689  addAutomaticObjDtors(B, E, S);
1690  if (BuildOpts.AddLifetime)
1691  addLifetimeEnds(B, E, S);
1692 }
1693 
1694 /// Add to current block automatic objects that leave the scope.
1695 void CFGBuilder::addLifetimeEnds(LocalScope::const_iterator B,
1696  LocalScope::const_iterator E, Stmt *S) {
1697  if (!BuildOpts.AddLifetime)
1698  return;
1699 
1700  if (B == E)
1701  return;
1702 
1703  // To go from B to E, one first goes up the scopes from B to P
1704  // then sideways in one scope from P to P' and then down
1705  // the scopes from P' to E.
1706  // The lifetime of all objects between B and P end.
1707  LocalScope::const_iterator P = B.shared_parent(E);
1708  int dist = B.distance(P);
1709  if (dist <= 0)
1710  return;
1711 
1712  // We need to perform the scope leaving in reverse order
1713  SmallVector<VarDecl *, 10> DeclsTrivial;
1714  SmallVector<VarDecl *, 10> DeclsNonTrivial;
1715  DeclsTrivial.reserve(dist);
1716  DeclsNonTrivial.reserve(dist);
1717 
1718  for (LocalScope::const_iterator I = B; I != P; ++I)
1719  if (hasTrivialDestructor(*I))
1720  DeclsTrivial.push_back(*I);
1721  else
1722  DeclsNonTrivial.push_back(*I);
1723 
1724  autoCreateBlock();
1725  // object with trivial destructor end their lifetime last (when storage
1726  // duration ends)
1727  for (SmallVectorImpl<VarDecl *>::reverse_iterator I = DeclsTrivial.rbegin(),
1728  E = DeclsTrivial.rend();
1729  I != E; ++I)
1730  appendLifetimeEnds(Block, *I, S);
1731 
1733  I = DeclsNonTrivial.rbegin(),
1734  E = DeclsNonTrivial.rend();
1735  I != E; ++I)
1736  appendLifetimeEnds(Block, *I, S);
1737 }
1738 
1739 /// Add to current block markers for ending scopes.
1740 void CFGBuilder::addScopesEnd(LocalScope::const_iterator B,
1741  LocalScope::const_iterator E, Stmt *S) {
1742  // If implicit destructors are enabled, we'll add scope ends in
1743  // addAutomaticObjDtors.
1744  if (BuildOpts.AddImplicitDtors)
1745  return;
1746 
1747  autoCreateBlock();
1748 
1749  for (auto I = DeclsWithEndedScope.rbegin(), E = DeclsWithEndedScope.rend();
1750  I != E; ++I)
1751  appendScopeEnd(Block, *I, S);
1752 
1753  return;
1754 }
1755 
1756 /// addAutomaticObjDtors - Add to current block automatic objects destructors
1757 /// for objects in range of local scope positions. Use S as trigger statement
1758 /// for destructors.
1759 void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B,
1760  LocalScope::const_iterator E, Stmt *S) {
1761  if (!BuildOpts.AddImplicitDtors)
1762  return;
1763 
1764  if (B == E)
1765  return;
1766 
1767  // We need to append the destructors in reverse order, but any one of them
1768  // may be a no-return destructor which changes the CFG. As a result, buffer
1769  // this sequence up and replay them in reverse order when appending onto the
1770  // CFGBlock(s).
1772  Decls.reserve(B.distance(E));
1773  for (LocalScope::const_iterator I = B; I != E; ++I)
1774  Decls.push_back(*I);
1775 
1776  for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(),
1777  E = Decls.rend();
1778  I != E; ++I) {
1779  if (hasTrivialDestructor(*I)) {
1780  // If AddScopes is enabled and *I is a first variable in a scope, add a
1781  // ScopeEnd marker in a Block.
1782  if (BuildOpts.AddScopes && DeclsWithEndedScope.count(*I)) {
1783  autoCreateBlock();
1784  appendScopeEnd(Block, *I, S);
1785  }
1786  continue;
1787  }
1788  // If this destructor is marked as a no-return destructor, we need to
1789  // create a new block for the destructor which does not have as a successor
1790  // anything built thus far: control won't flow out of this block.
1791  QualType Ty = (*I)->getType();
1792  if (Ty->isReferenceType()) {
1793  Ty = getReferenceInitTemporaryType((*I)->getInit());
1794  }
1795  Ty = Context->getBaseElementType(Ty);
1796 
1797  if (Ty->getAsCXXRecordDecl()->isAnyDestructorNoReturn())
1798  Block = createNoReturnBlock();
1799  else
1800  autoCreateBlock();
1801 
1802  // Add ScopeEnd just after automatic obj destructor.
1803  if (BuildOpts.AddScopes && DeclsWithEndedScope.count(*I))
1804  appendScopeEnd(Block, *I, S);
1805  appendAutomaticObjDtor(Block, *I, S);
1806  }
1807 }
1808 
1809 /// addImplicitDtorsForDestructor - Add implicit destructors generated for
1810 /// base and member objects in destructor.
1811 void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) {
1812  assert(BuildOpts.AddImplicitDtors &&
1813  "Can be called only when dtors should be added");
1814  const CXXRecordDecl *RD = DD->getParent();
1815 
1816  // At the end destroy virtual base objects.
1817  for (const auto &VI : RD->vbases()) {
1818  // TODO: Add a VirtualBaseBranch to see if the most derived class
1819  // (which is different from the current class) is responsible for
1820  // destroying them.
1821  const CXXRecordDecl *CD = VI.getType()->getAsCXXRecordDecl();
1822  if (!CD->hasTrivialDestructor()) {
1823  autoCreateBlock();
1824  appendBaseDtor(Block, &VI);
1825  }
1826  }
1827 
1828  // Before virtual bases destroy direct base objects.
1829  for (const auto &BI : RD->bases()) {
1830  if (!BI.isVirtual()) {
1831  const CXXRecordDecl *CD = BI.getType()->getAsCXXRecordDecl();
1832  if (!CD->hasTrivialDestructor()) {
1833  autoCreateBlock();
1834  appendBaseDtor(Block, &BI);
1835  }
1836  }
1837  }
1838 
1839  // First destroy member objects.
1840  for (auto *FI : RD->fields()) {
1841  // Check for constant size array. Set type to array element type.
1842  QualType QT = FI->getType();
1843  if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
1844  if (AT->getSize() == 0)
1845  continue;
1846  QT = AT->getElementType();
1847  }
1848 
1849  if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
1850  if (!CD->hasTrivialDestructor()) {
1851  autoCreateBlock();
1852  appendMemberDtor(Block, FI);
1853  }
1854  }
1855 }
1856 
1857 /// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either
1858 /// way return valid LocalScope object.
1859 LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) {
1860  if (Scope)
1861  return Scope;
1862  llvm::BumpPtrAllocator &alloc = cfg->getAllocator();
1863  return new (alloc.Allocate<LocalScope>())
1864  LocalScope(BumpVectorContext(alloc), ScopePos);
1865 }
1866 
1867 /// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement
1868 /// that should create implicit scope (e.g. if/else substatements).
1869 void CFGBuilder::addLocalScopeForStmt(Stmt *S) {
1870  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1871  !BuildOpts.AddScopes)
1872  return;
1873 
1874  LocalScope *Scope = nullptr;
1875 
1876  // For compound statement we will be creating explicit scope.
1877  if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
1878  for (auto *BI : CS->body()) {
1879  Stmt *SI = BI->stripLabelLikeStatements();
1880  if (DeclStmt *DS = dyn_cast<DeclStmt>(SI))
1881  Scope = addLocalScopeForDeclStmt(DS, Scope);
1882  }
1883  return;
1884  }
1885 
1886  // For any other statement scope will be implicit and as such will be
1887  // interesting only for DeclStmt.
1888  if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements()))
1889  addLocalScopeForDeclStmt(DS);
1890 }
1891 
1892 /// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will
1893 /// reuse Scope if not NULL.
1894 LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS,
1895  LocalScope* Scope) {
1896  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1897  !BuildOpts.AddScopes)
1898  return Scope;
1899 
1900  for (auto *DI : DS->decls())
1901  if (VarDecl *VD = dyn_cast<VarDecl>(DI))
1902  Scope = addLocalScopeForVarDecl(VD, Scope);
1903  return Scope;
1904 }
1905 
1906 bool CFGBuilder::hasTrivialDestructor(VarDecl *VD) {
1907  // Check for const references bound to temporary. Set type to pointee.
1908  QualType QT = VD->getType();
1909  if (QT->isReferenceType()) {
1910  // Attempt to determine whether this declaration lifetime-extends a
1911  // temporary.
1912  //
1913  // FIXME: This is incorrect. Non-reference declarations can lifetime-extend
1914  // temporaries, and a single declaration can extend multiple temporaries.
1915  // We should look at the storage duration on each nested
1916  // MaterializeTemporaryExpr instead.
1917 
1918  const Expr *Init = VD->getInit();
1919  if (!Init) {
1920  // Probably an exception catch-by-reference variable.
1921  // FIXME: It doesn't really mean that the object has a trivial destructor.
1922  // Also are there other cases?
1923  return true;
1924  }
1925 
1926  // Lifetime-extending a temporary?
1927  bool FoundMTE = false;
1928  QT = getReferenceInitTemporaryType(Init, &FoundMTE);
1929  if (!FoundMTE)
1930  return true;
1931  }
1932 
1933  // Check for constant size array. Set type to array element type.
1934  while (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
1935  if (AT->getSize() == 0)
1936  return true;
1937  QT = AT->getElementType();
1938  }
1939 
1940  // Check if type is a C++ class with non-trivial destructor.
1941  if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
1942  return !CD->hasDefinition() || CD->hasTrivialDestructor();
1943  return true;
1944 }
1945 
1946 /// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will
1947 /// create add scope for automatic objects and temporary objects bound to
1948 /// const reference. Will reuse Scope if not NULL.
1949 LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD,
1950  LocalScope* Scope) {
1951  assert(!(BuildOpts.AddImplicitDtors && BuildOpts.AddLifetime) &&
1952  "AddImplicitDtors and AddLifetime cannot be used at the same time");
1953  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1954  !BuildOpts.AddScopes)
1955  return Scope;
1956 
1957  // Check if variable is local.
1958  switch (VD->getStorageClass()) {
1959  case SC_None:
1960  case SC_Auto:
1961  case SC_Register:
1962  break;
1963  default: return Scope;
1964  }
1965 
1966  if (BuildOpts.AddImplicitDtors) {
1967  if (!hasTrivialDestructor(VD) || BuildOpts.AddScopes) {
1968  // Add the variable to scope
1969  Scope = createOrReuseLocalScope(Scope);
1970  Scope->addVar(VD);
1971  ScopePos = Scope->begin();
1972  }
1973  return Scope;
1974  }
1975 
1976  assert(BuildOpts.AddLifetime);
1977  // Add the variable to scope
1978  Scope = createOrReuseLocalScope(Scope);
1979  Scope->addVar(VD);
1980  ScopePos = Scope->begin();
1981  return Scope;
1982 }
1983 
1984 /// addLocalScopeAndDtors - For given statement add local scope for it and
1985 /// add destructors that will cleanup the scope. Will reuse Scope if not NULL.
1986 void CFGBuilder::addLocalScopeAndDtors(Stmt *S) {
1987  LocalScope::const_iterator scopeBeginPos = ScopePos;
1988  addLocalScopeForStmt(S);
1989  addAutomaticObjHandling(ScopePos, scopeBeginPos, S);
1990 }
1991 
1992 /// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for
1993 /// variables with automatic storage duration to CFGBlock's elements vector.
1994 /// Elements will be prepended to physical beginning of the vector which
1995 /// happens to be logical end. Use blocks terminator as statement that specifies
1996 /// destructors call site.
1997 /// FIXME: This mechanism for adding automatic destructors doesn't handle
1998 /// no-return destructors properly.
1999 void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
2000  LocalScope::const_iterator B, LocalScope::const_iterator E) {
2001  if (!BuildOpts.AddImplicitDtors)
2002  return;
2003  BumpVectorContext &C = cfg->getBumpVectorContext();
2004  CFGBlock::iterator InsertPos
2005  = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C);
2006  for (LocalScope::const_iterator I = B; I != E; ++I)
2007  InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I,
2008  Blk->getTerminatorStmt());
2009 }
2010 
2011 /// prependAutomaticObjLifetimeWithTerminator - Prepend lifetime CFGElements for
2012 /// variables with automatic storage duration to CFGBlock's elements vector.
2013 /// Elements will be prepended to physical beginning of the vector which
2014 /// happens to be logical end. Use blocks terminator as statement that specifies
2015 /// where lifetime ends.
2016 void CFGBuilder::prependAutomaticObjLifetimeWithTerminator(
2017  CFGBlock *Blk, LocalScope::const_iterator B, LocalScope::const_iterator E) {
2018  if (!BuildOpts.AddLifetime)
2019  return;
2020  BumpVectorContext &C = cfg->getBumpVectorContext();
2021  CFGBlock::iterator InsertPos =
2022  Blk->beginLifetimeEndsInsert(Blk->end(), B.distance(E), C);
2023  for (LocalScope::const_iterator I = B; I != E; ++I) {
2024  InsertPos =
2025  Blk->insertLifetimeEnds(InsertPos, *I, Blk->getTerminatorStmt());
2026  }
2027 }
2028 
2029 /// prependAutomaticObjScopeEndWithTerminator - Prepend scope end CFGElements for
2030 /// variables with automatic storage duration to CFGBlock's elements vector.
2031 /// Elements will be prepended to physical beginning of the vector which
2032 /// happens to be logical end. Use blocks terminator as statement that specifies
2033 /// where scope ends.
2034 const VarDecl *
2035 CFGBuilder::prependAutomaticObjScopeEndWithTerminator(
2036  CFGBlock *Blk, LocalScope::const_iterator B, LocalScope::const_iterator E) {
2037  if (!BuildOpts.AddScopes)
2038  return nullptr;
2039  BumpVectorContext &C = cfg->getBumpVectorContext();
2040  CFGBlock::iterator InsertPos =
2041  Blk->beginScopeEndInsert(Blk->end(), 1, C);
2042  LocalScope::const_iterator PlaceToInsert = B;
2043  for (LocalScope::const_iterator I = B; I != E; ++I)
2044  PlaceToInsert = I;
2045  Blk->insertScopeEnd(InsertPos, *PlaceToInsert, Blk->getTerminatorStmt());
2046  return *PlaceToInsert;
2047 }
2048 
2049 /// Visit - Walk the subtree of a statement and add extra
2050 /// blocks for ternary operators, &&, and ||. We also process "," and
2051 /// DeclStmts (which may contain nested control-flow).
2052 CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) {
2053  if (!S) {
2054  badCFG = true;
2055  return nullptr;
2056  }
2057 
2058  if (Expr *E = dyn_cast<Expr>(S))
2059  S = E->IgnoreParens();
2060 
2061  switch (S->getStmtClass()) {
2062  default:
2063  return VisitStmt(S, asc);
2064 
2065  case Stmt::AddrLabelExprClass:
2066  return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc);
2067 
2068  case Stmt::BinaryConditionalOperatorClass:
2069  return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc);
2070 
2071  case Stmt::BinaryOperatorClass:
2072  return VisitBinaryOperator(cast<BinaryOperator>(S), asc);
2073 
2074  case Stmt::BlockExprClass:
2075  return VisitBlockExpr(cast<BlockExpr>(S), asc);
2076 
2077  case Stmt::BreakStmtClass:
2078  return VisitBreakStmt(cast<BreakStmt>(S));
2079 
2080  case Stmt::CallExprClass:
2081  case Stmt::CXXOperatorCallExprClass:
2082  case Stmt::CXXMemberCallExprClass:
2083  case Stmt::UserDefinedLiteralClass:
2084  return VisitCallExpr(cast<CallExpr>(S), asc);
2085 
2086  case Stmt::CaseStmtClass:
2087  return VisitCaseStmt(cast<CaseStmt>(S));
2088 
2089  case Stmt::ChooseExprClass:
2090  return VisitChooseExpr(cast<ChooseExpr>(S), asc);
2091 
2092  case Stmt::CompoundStmtClass:
2093  return VisitCompoundStmt(cast<CompoundStmt>(S));
2094 
2095  case Stmt::ConditionalOperatorClass:
2096  return VisitConditionalOperator(cast<ConditionalOperator>(S), asc);
2097 
2098  case Stmt::ContinueStmtClass:
2099  return VisitContinueStmt(cast<ContinueStmt>(S));
2100 
2101  case Stmt::CXXCatchStmtClass:
2102  return VisitCXXCatchStmt(cast<CXXCatchStmt>(S));
2103 
2104  case Stmt::ExprWithCleanupsClass:
2105  return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc);
2106 
2107  case Stmt::CXXDefaultArgExprClass:
2108  case Stmt::CXXDefaultInitExprClass:
2109  // FIXME: The expression inside a CXXDefaultArgExpr is owned by the
2110  // called function's declaration, not by the caller. If we simply add
2111  // this expression to the CFG, we could end up with the same Expr
2112  // appearing multiple times.
2113  // PR13385 / <rdar://problem/12156507>
2114  //
2115  // It's likewise possible for multiple CXXDefaultInitExprs for the same
2116  // expression to be used in the same function (through aggregate
2117  // initialization).
2118  return VisitStmt(S, asc);
2119 
2120  case Stmt::CXXBindTemporaryExprClass:
2121  return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc);
2122 
2123  case Stmt::CXXConstructExprClass:
2124  return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc);
2125 
2126  case Stmt::CXXNewExprClass:
2127  return VisitCXXNewExpr(cast<CXXNewExpr>(S), asc);
2128 
2129  case Stmt::CXXDeleteExprClass:
2130  return VisitCXXDeleteExpr(cast<CXXDeleteExpr>(S), asc);
2131 
2132  case Stmt::CXXFunctionalCastExprClass:
2133  return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc);
2134 
2135  case Stmt::CXXTemporaryObjectExprClass:
2136  return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc);
2137 
2138  case Stmt::CXXThrowExprClass:
2139  return VisitCXXThrowExpr(cast<CXXThrowExpr>(S));
2140 
2141  case Stmt::CXXTryStmtClass:
2142  return VisitCXXTryStmt(cast<CXXTryStmt>(S));
2143 
2144  case Stmt::CXXForRangeStmtClass:
2145  return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S));
2146 
2147  case Stmt::DeclStmtClass:
2148  return VisitDeclStmt(cast<DeclStmt>(S));
2149 
2150  case Stmt::DefaultStmtClass:
2151  return VisitDefaultStmt(cast<DefaultStmt>(S));
2152 
2153  case Stmt::DoStmtClass:
2154  return VisitDoStmt(cast<DoStmt>(S));
2155 
2156  case Stmt::ForStmtClass:
2157  return VisitForStmt(cast<ForStmt>(S));
2158 
2159  case Stmt::GotoStmtClass:
2160  return VisitGotoStmt(cast<GotoStmt>(S));
2161 
2162  case Stmt::GCCAsmStmtClass:
2163  return VisitGCCAsmStmt(cast<GCCAsmStmt>(S), asc);
2164 
2165  case Stmt::IfStmtClass:
2166  return VisitIfStmt(cast<IfStmt>(S));
2167 
2168  case Stmt::ImplicitCastExprClass:
2169  return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc);
2170 
2171  case Stmt::ConstantExprClass:
2172  return VisitConstantExpr(cast<ConstantExpr>(S), asc);
2173 
2174  case Stmt::IndirectGotoStmtClass:
2175  return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S));
2176 
2177  case Stmt::LabelStmtClass:
2178  return VisitLabelStmt(cast<LabelStmt>(S));
2179 
2180  case Stmt::LambdaExprClass:
2181  return VisitLambdaExpr(cast<LambdaExpr>(S), asc);
2182 
2183  case Stmt::MaterializeTemporaryExprClass:
2184  return VisitMaterializeTemporaryExpr(cast<MaterializeTemporaryExpr>(S),
2185  asc);
2186 
2187  case Stmt::MemberExprClass:
2188  return VisitMemberExpr(cast<MemberExpr>(S), asc);
2189 
2190  case Stmt::NullStmtClass:
2191  return Block;
2192 
2193  case Stmt::ObjCAtCatchStmtClass:
2194  return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S));
2195 
2196  case Stmt::ObjCAutoreleasePoolStmtClass:
2197  return VisitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(S));
2198 
2199  case Stmt::ObjCAtSynchronizedStmtClass:
2200  return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S));
2201 
2202  case Stmt::ObjCAtThrowStmtClass:
2203  return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S));
2204 
2205  case Stmt::ObjCAtTryStmtClass:
2206  return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S));
2207 
2208  case Stmt::ObjCForCollectionStmtClass:
2209  return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S));
2210 
2211  case Stmt::ObjCMessageExprClass:
2212  return VisitObjCMessageExpr(cast<ObjCMessageExpr>(S), asc);
2213 
2214  case Stmt::OpaqueValueExprClass:
2215  return Block;
2216 
2217  case Stmt::PseudoObjectExprClass:
2218  return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S));
2219 
2220  case Stmt::ReturnStmtClass:
2221  case Stmt::CoreturnStmtClass:
2222  return VisitReturnStmt(S);
2223 
2224  case Stmt::SEHExceptStmtClass:
2225  return VisitSEHExceptStmt(cast<SEHExceptStmt>(S));
2226 
2227  case Stmt::SEHFinallyStmtClass:
2228  return VisitSEHFinallyStmt(cast<SEHFinallyStmt>(S));
2229 
2230  case Stmt::SEHLeaveStmtClass:
2231  return VisitSEHLeaveStmt(cast<SEHLeaveStmt>(S));
2232 
2233  case Stmt::SEHTryStmtClass:
2234  return VisitSEHTryStmt(cast<SEHTryStmt>(S));
2235 
2236  case Stmt::UnaryExprOrTypeTraitExprClass:
2237  return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S),
2238  asc);
2239 
2240  case Stmt::StmtExprClass:
2241  return VisitStmtExpr(cast<StmtExpr>(S), asc);
2242 
2243  case Stmt::SwitchStmtClass:
2244  return VisitSwitchStmt(cast<SwitchStmt>(S));
2245 
2246  case Stmt::UnaryOperatorClass:
2247  return VisitUnaryOperator(cast<UnaryOperator>(S), asc);
2248 
2249  case Stmt::WhileStmtClass:
2250  return VisitWhileStmt(cast<WhileStmt>(S));
2251  }
2252 }
2253 
2254 CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) {
2255  if (asc.alwaysAdd(*this, S)) {
2256  autoCreateBlock();
2257  appendStmt(Block, S);
2258  }
2259 
2260  return VisitChildren(S);
2261 }
2262 
2263 /// VisitChildren - Visit the children of a Stmt.
2264 CFGBlock *CFGBuilder::VisitChildren(Stmt *S) {
2265  CFGBlock *B = Block;
2266 
2267  // Visit the children in their reverse order so that they appear in
2268  // left-to-right (natural) order in the CFG.
2269  reverse_children RChildren(S);
2270  for (reverse_children::iterator I = RChildren.begin(), E = RChildren.end();
2271  I != E; ++I) {
2272  if (Stmt *Child = *I)
2273  if (CFGBlock *R = Visit(Child))
2274  B = R;
2275  }
2276  return B;
2277 }
2278 
2279 CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A,
2280  AddStmtChoice asc) {
2281  AddressTakenLabels.insert(A->getLabel());
2282 
2283  if (asc.alwaysAdd(*this, A)) {
2284  autoCreateBlock();
2285  appendStmt(Block, A);
2286  }
2287 
2288  return Block;
2289 }
2290 
2291 CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U,
2292  AddStmtChoice asc) {
2293  if (asc.alwaysAdd(*this, U)) {
2294  autoCreateBlock();
2295  appendStmt(Block, U);
2296  }
2297 
2298  return Visit(U->getSubExpr(), AddStmtChoice());
2299 }
2300 
2301 CFGBlock *CFGBuilder::VisitLogicalOperator(BinaryOperator *B) {
2302  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2303  appendStmt(ConfluenceBlock, B);
2304 
2305  if (badCFG)
2306  return nullptr;
2307 
2308  return VisitLogicalOperator(B, nullptr, ConfluenceBlock,
2309  ConfluenceBlock).first;
2310 }
2311 
2312 std::pair<CFGBlock*, CFGBlock*>
2313 CFGBuilder::VisitLogicalOperator(BinaryOperator *B,
2314  Stmt *Term,
2315  CFGBlock *TrueBlock,
2316  CFGBlock *FalseBlock) {
2317  // Introspect the RHS. If it is a nested logical operation, we recursively
2318  // build the CFG using this function. Otherwise, resort to default
2319  // CFG construction behavior.
2320  Expr *RHS = B->getRHS()->IgnoreParens();
2321  CFGBlock *RHSBlock, *ExitBlock;
2322 
2323  do {
2324  if (BinaryOperator *B_RHS = dyn_cast<BinaryOperator>(RHS))
2325  if (B_RHS->isLogicalOp()) {
2326  std::tie(RHSBlock, ExitBlock) =
2327  VisitLogicalOperator(B_RHS, Term, TrueBlock, FalseBlock);
2328  break;
2329  }
2330 
2331  // The RHS is not a nested logical operation. Don't push the terminator
2332  // down further, but instead visit RHS and construct the respective
2333  // pieces of the CFG, and link up the RHSBlock with the terminator
2334  // we have been provided.
2335  ExitBlock = RHSBlock = createBlock(false);
2336 
2337  // Even though KnownVal is only used in the else branch of the next
2338  // conditional, tryEvaluateBool performs additional checking on the
2339  // Expr, so it should be called unconditionally.
2340  TryResult KnownVal = tryEvaluateBool(RHS);
2341  if (!KnownVal.isKnown())
2342  KnownVal = tryEvaluateBool(B);
2343 
2344  if (!Term) {
2345  assert(TrueBlock == FalseBlock);
2346  addSuccessor(RHSBlock, TrueBlock);
2347  }
2348  else {
2349  RHSBlock->setTerminator(Term);
2350  addSuccessor(RHSBlock, TrueBlock, !KnownVal.isFalse());
2351  addSuccessor(RHSBlock, FalseBlock, !KnownVal.isTrue());
2352  }
2353 
2354  Block = RHSBlock;
2355  RHSBlock = addStmt(RHS);
2356  }
2357  while (false);
2358 
2359  if (badCFG)
2360  return std::make_pair(nullptr, nullptr);
2361 
2362  // Generate the blocks for evaluating the LHS.
2363  Expr *LHS = B->getLHS()->IgnoreParens();
2364 
2365  if (BinaryOperator *B_LHS = dyn_cast<BinaryOperator>(LHS))
2366  if (B_LHS->isLogicalOp()) {
2367  if (B->getOpcode() == BO_LOr)
2368  FalseBlock = RHSBlock;
2369  else
2370  TrueBlock = RHSBlock;
2371 
2372  // For the LHS, treat 'B' as the terminator that we want to sink
2373  // into the nested branch. The RHS always gets the top-most
2374  // terminator.
2375  return VisitLogicalOperator(B_LHS, B, TrueBlock, FalseBlock);
2376  }
2377 
2378  // Create the block evaluating the LHS.
2379  // This contains the '&&' or '||' as the terminator.
2380  CFGBlock *LHSBlock = createBlock(false);
2381  LHSBlock->setTerminator(B);
2382 
2383  Block = LHSBlock;
2384  CFGBlock *EntryLHSBlock = addStmt(LHS);
2385 
2386  if (badCFG)
2387  return std::make_pair(nullptr, nullptr);
2388 
2389  // See if this is a known constant.
2390  TryResult KnownVal = tryEvaluateBool(LHS);
2391 
2392  // Now link the LHSBlock with RHSBlock.
2393  if (B->getOpcode() == BO_LOr) {
2394  addSuccessor(LHSBlock, TrueBlock, !KnownVal.isFalse());
2395  addSuccessor(LHSBlock, RHSBlock, !KnownVal.isTrue());
2396  } else {
2397  assert(B->getOpcode() == BO_LAnd);
2398  addSuccessor(LHSBlock, RHSBlock, !KnownVal.isFalse());
2399  addSuccessor(LHSBlock, FalseBlock, !KnownVal.isTrue());
2400  }
2401 
2402  return std::make_pair(EntryLHSBlock, ExitBlock);
2403 }
2404 
2405 CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B,
2406  AddStmtChoice asc) {
2407  // && or ||
2408  if (B->isLogicalOp())
2409  return VisitLogicalOperator(B);
2410 
2411  if (B->getOpcode() == BO_Comma) { // ,
2412  autoCreateBlock();
2413  appendStmt(Block, B);
2414  addStmt(B->getRHS());
2415  return addStmt(B->getLHS());
2416  }
2417 
2418  if (B->isAssignmentOp()) {
2419  if (asc.alwaysAdd(*this, B)) {
2420  autoCreateBlock();
2421  appendStmt(Block, B);
2422  }
2423  Visit(B->getLHS());
2424  return Visit(B->getRHS());
2425  }
2426 
2427  if (asc.alwaysAdd(*this, B)) {
2428  autoCreateBlock();
2429  appendStmt(Block, B);
2430  }
2431 
2432  CFGBlock *RBlock = Visit(B->getRHS());
2433  CFGBlock *LBlock = Visit(B->getLHS());
2434  // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr
2435  // containing a DoStmt, and the LHS doesn't create a new block, then we should
2436  // return RBlock. Otherwise we'll incorrectly return NULL.
2437  return (LBlock ? LBlock : RBlock);
2438 }
2439 
2440 CFGBlock *CFGBuilder::VisitNoRecurse(Expr *E, AddStmtChoice asc) {
2441  if (asc.alwaysAdd(*this, E)) {
2442  autoCreateBlock();
2443  appendStmt(Block, E);
2444  }
2445  return Block;
2446 }
2447 
2448 CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) {
2449  // "break" is a control-flow statement. Thus we stop processing the current
2450  // block.
2451  if (badCFG)
2452  return nullptr;
2453 
2454  // Now create a new block that ends with the break statement.
2455  Block = createBlock(false);
2456  Block->setTerminator(B);
2457 
2458  // If there is no target for the break, then we are looking at an incomplete
2459  // AST. This means that the CFG cannot be constructed.
2460  if (BreakJumpTarget.block) {
2461  addAutomaticObjHandling(ScopePos, BreakJumpTarget.scopePosition, B);
2462  addSuccessor(Block, BreakJumpTarget.block);
2463  } else
2464  badCFG = true;
2465 
2466  return Block;
2467 }
2468 
2469 static bool CanThrow(Expr *E, ASTContext &Ctx) {
2470  QualType Ty = E->getType();
2471  if (Ty->isFunctionPointerType())
2472  Ty = Ty->getAs<PointerType>()->getPointeeType();
2473  else if (Ty->isBlockPointerType())
2474  Ty = Ty->getAs<BlockPointerType>()->getPointeeType();
2475 
2476  const FunctionType *FT = Ty->getAs<FunctionType>();
2477  if (FT) {
2478  if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT))
2479  if (!isUnresolvedExceptionSpec(Proto->getExceptionSpecType()) &&
2480  Proto->isNothrow())
2481  return false;
2482  }
2483  return true;
2484 }
2485 
2486 CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) {
2487  // Compute the callee type.
2488  QualType calleeType = C->getCallee()->getType();
2489  if (calleeType == Context->BoundMemberTy) {
2490  QualType boundType = Expr::findBoundMemberType(C->getCallee());
2491 
2492  // We should only get a null bound type if processing a dependent
2493  // CFG. Recover by assuming nothing.
2494  if (!boundType.isNull()) calleeType = boundType;
2495  }
2496 
2497  // If this is a call to a no-return function, this stops the block here.
2498  bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn();
2499 
2500  bool AddEHEdge = false;
2501 
2502  // Languages without exceptions are assumed to not throw.
2503  if (Context->getLangOpts().Exceptions) {
2504  if (BuildOpts.AddEHEdges)
2505  AddEHEdge = true;
2506  }
2507 
2508  // If this is a call to a builtin function, it might not actually evaluate
2509  // its arguments. Don't add them to the CFG if this is the case.
2510  bool OmitArguments = false;
2511 
2512  if (FunctionDecl *FD = C->getDirectCallee()) {
2513  // TODO: Support construction contexts for variadic function arguments.
2514  // These are a bit problematic and not very useful because passing
2515  // C++ objects as C-style variadic arguments doesn't work in general
2516  // (see [expr.call]).
2517  if (!FD->isVariadic())
2518  findConstructionContextsForArguments(C);
2519 
2520  if (FD->isNoReturn() || C->isBuiltinAssumeFalse(*Context))
2521  NoReturn = true;
2522  if (FD->hasAttr<NoThrowAttr>())
2523  AddEHEdge = false;
2524  if (FD->getBuiltinID() == Builtin::BI__builtin_object_size ||
2525  FD->getBuiltinID() == Builtin::BI__builtin_dynamic_object_size)
2526  OmitArguments = true;
2527  }
2528 
2529  if (!CanThrow(C->getCallee(), *Context))
2530  AddEHEdge = false;
2531 
2532  if (OmitArguments) {
2533  assert(!NoReturn && "noreturn calls with unevaluated args not implemented");
2534  assert(!AddEHEdge && "EH calls with unevaluated args not implemented");
2535  autoCreateBlock();
2536  appendStmt(Block, C);
2537  return Visit(C->getCallee());
2538  }
2539 
2540  if (!NoReturn && !AddEHEdge) {
2541  autoCreateBlock();
2542  appendCall(Block, C);
2543 
2544  return VisitChildren(C);
2545  }
2546 
2547  if (Block) {
2548  Succ = Block;
2549  if (badCFG)
2550  return nullptr;
2551  }
2552 
2553  if (NoReturn)
2554  Block = createNoReturnBlock();
2555  else
2556  Block = createBlock();
2557 
2558  appendCall(Block, C);
2559 
2560  if (AddEHEdge) {
2561  // Add exceptional edges.
2562  if (TryTerminatedBlock)
2563  addSuccessor(Block, TryTerminatedBlock);
2564  else
2565  addSuccessor(Block, &cfg->getExit());
2566  }
2567 
2568  return VisitChildren(C);
2569 }
2570 
2571 CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C,
2572  AddStmtChoice asc) {
2573  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2574  appendStmt(ConfluenceBlock, C);
2575  if (badCFG)
2576  return nullptr;
2577 
2578  AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2579  Succ = ConfluenceBlock;
2580  Block = nullptr;
2581  CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd);
2582  if (badCFG)
2583  return nullptr;
2584 
2585  Succ = ConfluenceBlock;
2586  Block = nullptr;
2587  CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd);
2588  if (badCFG)
2589  return nullptr;
2590 
2591  Block = createBlock(false);
2592  // See if this is a known constant.
2593  const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2594  addSuccessor(Block, KnownVal.isFalse() ? nullptr : LHSBlock);
2595  addSuccessor(Block, KnownVal.isTrue() ? nullptr : RHSBlock);
2596  Block->setTerminator(C);
2597  return addStmt(C->getCond());
2598 }
2599 
2600 CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) {
2601  LocalScope::const_iterator scopeBeginPos = ScopePos;
2602  addLocalScopeForStmt(C);
2603 
2604  if (!C->body_empty() && !isa<ReturnStmt>(*C->body_rbegin())) {
2605  // If the body ends with a ReturnStmt, the dtors will be added in
2606  // VisitReturnStmt.
2607  addAutomaticObjHandling(ScopePos, scopeBeginPos, C);
2608  }
2609 
2610  CFGBlock *LastBlock = Block;
2611 
2613  I != E; ++I ) {
2614  // If we hit a segment of code just containing ';' (NullStmts), we can
2615  // get a null block back. In such cases, just use the LastBlock
2616  if (CFGBlock *newBlock = addStmt(*I))
2617  LastBlock = newBlock;
2618 
2619  if (badCFG)
2620  return nullptr;
2621  }
2622 
2623  return LastBlock;
2624 }
2625 
2626 CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C,
2627  AddStmtChoice asc) {
2628  const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C);
2629  const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : nullptr);
2630 
2631  // Create the confluence block that will "merge" the results of the ternary
2632  // expression.
2633  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2634  appendStmt(ConfluenceBlock, C);
2635  if (badCFG)
2636  return nullptr;
2637 
2638  AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2639 
2640  // Create a block for the LHS expression if there is an LHS expression. A
2641  // GCC extension allows LHS to be NULL, causing the condition to be the
2642  // value that is returned instead.
2643  // e.g: x ?: y is shorthand for: x ? x : y;
2644  Succ = ConfluenceBlock;
2645  Block = nullptr;
2646  CFGBlock *LHSBlock = nullptr;
2647  const Expr *trueExpr = C->getTrueExpr();
2648  if (trueExpr != opaqueValue) {
2649  LHSBlock = Visit(C->getTrueExpr(), alwaysAdd);
2650  if (badCFG)
2651  return nullptr;
2652  Block = nullptr;
2653  }
2654  else
2655  LHSBlock = ConfluenceBlock;
2656 
2657  // Create the block for the RHS expression.
2658  Succ = ConfluenceBlock;
2659  CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd);
2660  if (badCFG)
2661  return nullptr;
2662 
2663  // If the condition is a logical '&&' or '||', build a more accurate CFG.
2664  if (BinaryOperator *Cond =
2665  dyn_cast<BinaryOperator>(C->getCond()->IgnoreParens()))
2666  if (Cond->isLogicalOp())
2667  return VisitLogicalOperator(Cond, C, LHSBlock, RHSBlock).first;
2668 
2669  // Create the block that will contain the condition.
2670  Block = createBlock(false);
2671 
2672  // See if this is a known constant.
2673  const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2674  addSuccessor(Block, LHSBlock, !KnownVal.isFalse());
2675  addSuccessor(Block, RHSBlock, !KnownVal.isTrue());
2676  Block->setTerminator(C);
2677  Expr *condExpr = C->getCond();
2678 
2679  if (opaqueValue) {
2680  // Run the condition expression if it's not trivially expressed in
2681  // terms of the opaque value (or if there is no opaque value).
2682  if (condExpr != opaqueValue)
2683  addStmt(condExpr);
2684 
2685  // Before that, run the common subexpression if there was one.
2686  // At least one of this or the above will be run.
2687  return addStmt(BCO->getCommon());
2688  }
2689 
2690  return addStmt(condExpr);
2691 }
2692 
2693 CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) {
2694  // Check if the Decl is for an __label__. If so, elide it from the
2695  // CFG entirely.
2696  if (isa<LabelDecl>(*DS->decl_begin()))
2697  return Block;
2698 
2699  // This case also handles static_asserts.
2700  if (DS->isSingleDecl())
2701  return VisitDeclSubExpr(DS);
2702 
2703  CFGBlock *B = nullptr;
2704 
2705  // Build an individual DeclStmt for each decl.
2707  E = DS->decl_rend();
2708  I != E; ++I) {
2709 
2710  // Allocate the DeclStmt using the BumpPtrAllocator. It will get
2711  // automatically freed with the CFG.
2712  DeclGroupRef DG(*I);
2713  Decl *D = *I;
2714  DeclStmt *DSNew = new (Context) DeclStmt(DG, D->getLocation(), GetEndLoc(D));
2715  cfg->addSyntheticDeclStmt(DSNew, DS);
2716 
2717  // Append the fake DeclStmt to block.
2718  B = VisitDeclSubExpr(DSNew);
2719  }
2720 
2721  return B;
2722 }
2723 
2724 /// VisitDeclSubExpr - Utility method to add block-level expressions for
2725 /// DeclStmts and initializers in them.
2726 CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) {
2727  assert(DS->isSingleDecl() && "Can handle single declarations only.");
2728  VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl());
2729 
2730  if (!VD) {
2731  // Of everything that can be declared in a DeclStmt, only VarDecls impact
2732  // runtime semantics.
2733  return Block;
2734  }
2735 
2736  bool HasTemporaries = false;
2737 
2738  // Guard static initializers under a branch.
2739  CFGBlock *blockAfterStaticInit = nullptr;
2740 
2741  if (BuildOpts.AddStaticInitBranches && VD->isStaticLocal()) {
2742  // For static variables, we need to create a branch to track
2743  // whether or not they are initialized.
2744  if (Block) {
2745  Succ = Block;
2746  Block = nullptr;
2747  if (badCFG)
2748  return nullptr;
2749  }
2750  blockAfterStaticInit = Succ;
2751  }
2752 
2753  // Destructors of temporaries in initialization expression should be called
2754  // after initialization finishes.
2755  Expr *Init = VD->getInit();
2756  if (Init) {
2757  HasTemporaries = isa<ExprWithCleanups>(Init);
2758 
2759  if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
2760  // Generate destructors for temporaries in initialization expression.
2761  TempDtorContext Context;
2762  VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
2763  /*BindToTemporary=*/false, Context);
2764  }
2765  }
2766 
2767  autoCreateBlock();
2768  appendStmt(Block, DS);
2769 
2770  findConstructionContexts(
2771  ConstructionContextLayer::create(cfg->getBumpVectorContext(), DS),
2772  Init);
2773 
2774  // Keep track of the last non-null block, as 'Block' can be nulled out
2775  // if the initializer expression is something like a 'while' in a
2776  // statement-expression.
2777  CFGBlock *LastBlock = Block;
2778 
2779  if (Init) {
2780  if (HasTemporaries) {
2781  // For expression with temporaries go directly to subexpression to omit
2782  // generating destructors for the second time.
2783  ExprWithCleanups *EC = cast<ExprWithCleanups>(Init);
2784  if (CFGBlock *newBlock = Visit(EC->getSubExpr()))
2785  LastBlock = newBlock;
2786  }
2787  else {
2788  if (CFGBlock *newBlock = Visit(Init))
2789  LastBlock = newBlock;
2790  }
2791  }
2792 
2793  // If the type of VD is a VLA, then we must process its size expressions.
2794  for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr());
2795  VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr())) {
2796  if (CFGBlock *newBlock = addStmt(VA->getSizeExpr()))
2797  LastBlock = newBlock;
2798  }
2799 
2800  maybeAddScopeBeginForVarDecl(Block, VD, DS);
2801 
2802  // Remove variable from local scope.
2803  if (ScopePos && VD == *ScopePos)
2804  ++ScopePos;
2805 
2806  CFGBlock *B = LastBlock;
2807  if (blockAfterStaticInit) {
2808  Succ = B;
2809  Block = createBlock(false);
2810  Block->setTerminator(DS);
2811  addSuccessor(Block, blockAfterStaticInit);
2812  addSuccessor(Block, B);
2813  B = Block;
2814  }
2815 
2816  return B;
2817 }
2818 
2819 CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) {
2820  // We may see an if statement in the middle of a basic block, or it may be the
2821  // first statement we are processing. In either case, we create a new basic
2822  // block. First, we create the blocks for the then...else statements, and
2823  // then we create the block containing the if statement. If we were in the
2824  // middle of a block, we stop processing that block. That block is then the
2825  // implicit successor for the "then" and "else" clauses.
2826 
2827  // Save local scope position because in case of condition variable ScopePos
2828  // won't be restored when traversing AST.
2829  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2830 
2831  // Create local scope for C++17 if init-stmt if one exists.
2832  if (Stmt *Init = I->getInit())
2833  addLocalScopeForStmt(Init);
2834 
2835  // Create local scope for possible condition variable.
2836  // Store scope position. Add implicit destructor.
2837  if (VarDecl *VD = I->getConditionVariable())
2838  addLocalScopeForVarDecl(VD);
2839 
2840  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), I);
2841 
2842  // The block we were processing is now finished. Make it the successor
2843  // block.
2844  if (Block) {
2845  Succ = Block;
2846  if (badCFG)
2847  return nullptr;
2848  }
2849 
2850  // Process the false branch.
2851  CFGBlock *ElseBlock = Succ;
2852 
2853  if (Stmt *Else = I->getElse()) {
2854  SaveAndRestore<CFGBlock*> sv(Succ);
2855 
2856  // NULL out Block so that the recursive call to Visit will
2857  // create a new basic block.
2858  Block = nullptr;
2859 
2860  // If branch is not a compound statement create implicit scope
2861  // and add destructors.
2862  if (!isa<CompoundStmt>(Else))
2863  addLocalScopeAndDtors(Else);
2864 
2865  ElseBlock = addStmt(Else);
2866 
2867  if (!ElseBlock) // Can occur when the Else body has all NullStmts.
2868  ElseBlock = sv.get();
2869  else if (Block) {
2870  if (badCFG)
2871  return nullptr;
2872  }
2873  }
2874 
2875  // Process the true branch.
2876  CFGBlock *ThenBlock;
2877  {
2878  Stmt *Then = I->getThen();
2879  assert(Then);
2880  SaveAndRestore<CFGBlock*> sv(Succ);
2881  Block = nullptr;
2882 
2883  // If branch is not a compound statement create implicit scope
2884  // and add destructors.
2885  if (!isa<CompoundStmt>(Then))
2886  addLocalScopeAndDtors(Then);
2887 
2888  ThenBlock = addStmt(Then);
2889 
2890  if (!ThenBlock) {
2891  // We can reach here if the "then" body has all NullStmts.
2892  // Create an empty block so we can distinguish between true and false
2893  // branches in path-sensitive analyses.
2894  ThenBlock = createBlock(false);
2895  addSuccessor(ThenBlock, sv.get());
2896  } else if (Block) {
2897  if (badCFG)
2898  return nullptr;
2899  }
2900  }
2901 
2902  // Specially handle "if (expr1 || ...)" and "if (expr1 && ...)" by
2903  // having these handle the actual control-flow jump. Note that
2904  // if we introduce a condition variable, e.g. "if (int x = exp1 || exp2)"
2905  // we resort to the old control-flow behavior. This special handling
2906  // removes infeasible paths from the control-flow graph by having the
2907  // control-flow transfer of '&&' or '||' go directly into the then/else
2908  // blocks directly.
2909  BinaryOperator *Cond =
2911  ? nullptr
2912  : dyn_cast<BinaryOperator>(I->getCond()->IgnoreParens());
2913  CFGBlock *LastBlock;
2914  if (Cond && Cond->isLogicalOp())
2915  LastBlock = VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first;
2916  else {
2917  // Now create a new block containing the if statement.
2918  Block = createBlock(false);
2919 
2920  // Set the terminator of the new block to the If statement.
2921  Block->setTerminator(I);
2922 
2923  // See if this is a known constant.
2924  const TryResult &KnownVal = tryEvaluateBool(I->getCond());
2925 
2926  // Add the successors. If we know that specific branches are
2927  // unreachable, inform addSuccessor() of that knowledge.
2928  addSuccessor(Block, ThenBlock, /* isReachable = */ !KnownVal.isFalse());
2929  addSuccessor(Block, ElseBlock, /* isReachable = */ !KnownVal.isTrue());
2930 
2931  // Add the condition as the last statement in the new block. This may
2932  // create new blocks as the condition may contain control-flow. Any newly
2933  // created blocks will be pointed to be "Block".
2934  LastBlock = addStmt(I->getCond());
2935 
2936  // If the IfStmt contains a condition variable, add it and its
2937  // initializer to the CFG.
2938  if (const DeclStmt* DS = I->getConditionVariableDeclStmt()) {
2939  autoCreateBlock();
2940  LastBlock = addStmt(const_cast<DeclStmt *>(DS));
2941  }
2942  }
2943 
2944  // Finally, if the IfStmt contains a C++17 init-stmt, add it to the CFG.
2945  if (Stmt *Init = I->getInit()) {
2946  autoCreateBlock();
2947  LastBlock = addStmt(Init);
2948  }
2949 
2950  return LastBlock;
2951 }
2952 
2953 CFGBlock *CFGBuilder::VisitReturnStmt(Stmt *S) {
2954  // If we were in the middle of a block we stop processing that block.
2955  //
2956  // NOTE: If a "return" or "co_return" appears in the middle of a block, this
2957  // means that the code afterwards is DEAD (unreachable). We still keep
2958  // a basic block for that code; a simple "mark-and-sweep" from the entry
2959  // block will be able to report such dead blocks.
2960  assert(isa<ReturnStmt>(S) || isa<CoreturnStmt>(S));
2961 
2962  // Create the new block.
2963  Block = createBlock(false);
2964 
2965  addAutomaticObjHandling(ScopePos, LocalScope::const_iterator(), S);
2966 
2967  if (auto *R = dyn_cast<ReturnStmt>(S))
2968  findConstructionContexts(
2969  ConstructionContextLayer::create(cfg->getBumpVectorContext(), R),
2970  R->getRetValue());
2971 
2972  // If the one of the destructors does not return, we already have the Exit
2973  // block as a successor.
2974  if (!Block->hasNoReturnElement())
2975  addSuccessor(Block, &cfg->getExit());
2976 
2977  // Add the return statement to the block. This may create new blocks if R
2978  // contains control-flow (short-circuit operations).
2979  return VisitStmt(S, AddStmtChoice::AlwaysAdd);
2980 }
2981 
2982 CFGBlock *CFGBuilder::VisitSEHExceptStmt(SEHExceptStmt *ES) {
2983  // SEHExceptStmt are treated like labels, so they are the first statement in a
2984  // block.
2985 
2986  // Save local scope position because in case of exception variable ScopePos
2987  // won't be restored when traversing AST.
2988  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2989 
2990  addStmt(ES->getBlock());
2991  CFGBlock *SEHExceptBlock = Block;
2992  if (!SEHExceptBlock)
2993  SEHExceptBlock = createBlock();
2994 
2995  appendStmt(SEHExceptBlock, ES);
2996 
2997  // Also add the SEHExceptBlock as a label, like with regular labels.
2998  SEHExceptBlock->setLabel(ES);
2999 
3000  // Bail out if the CFG is bad.
3001  if (badCFG)
3002  return nullptr;
3003 
3004  // We set Block to NULL to allow lazy creation of a new block (if necessary).
3005  Block = nullptr;
3006 
3007  return SEHExceptBlock;
3008 }
3009 
3010 CFGBlock *CFGBuilder::VisitSEHFinallyStmt(SEHFinallyStmt *FS) {
3011  return VisitCompoundStmt(FS->getBlock());
3012 }
3013 
3014 CFGBlock *CFGBuilder::VisitSEHLeaveStmt(SEHLeaveStmt *LS) {
3015  // "__leave" is a control-flow statement. Thus we stop processing the current
3016  // block.
3017  if (badCFG)
3018  return nullptr;
3019 
3020  // Now create a new block that ends with the __leave statement.
3021  Block = createBlock(false);
3022  Block->setTerminator(LS);
3023 
3024  // If there is no target for the __leave, then we are looking at an incomplete
3025  // AST. This means that the CFG cannot be constructed.
3026  if (SEHLeaveJumpTarget.block) {
3027  addAutomaticObjHandling(ScopePos, SEHLeaveJumpTarget.scopePosition, LS);
3028  addSuccessor(Block, SEHLeaveJumpTarget.block);
3029  } else
3030  badCFG = true;
3031 
3032  return Block;
3033 }
3034 
3035 CFGBlock *CFGBuilder::VisitSEHTryStmt(SEHTryStmt *Terminator) {
3036  // "__try"/"__except"/"__finally" is a control-flow statement. Thus we stop
3037  // processing the current block.
3038  CFGBlock *SEHTrySuccessor = nullptr;
3039 
3040  if (Block) {
3041  if (badCFG)
3042  return nullptr;
3043  SEHTrySuccessor = Block;
3044  } else SEHTrySuccessor = Succ;
3045 
3046  // FIXME: Implement __finally support.
3047  if (Terminator->getFinallyHandler())
3048  return NYS();
3049 
3050  CFGBlock *PrevSEHTryTerminatedBlock = TryTerminatedBlock;
3051 
3052  // Create a new block that will contain the __try statement.
3053  CFGBlock *NewTryTerminatedBlock = createBlock(false);
3054 
3055  // Add the terminator in the __try block.
3056  NewTryTerminatedBlock->setTerminator(Terminator);
3057 
3058  if (SEHExceptStmt *Except = Terminator->getExceptHandler()) {
3059  // The code after the try is the implicit successor if there's an __except.
3060  Succ = SEHTrySuccessor;
3061  Block = nullptr;
3062  CFGBlock *ExceptBlock = VisitSEHExceptStmt(Except);
3063  if (!ExceptBlock)
3064  return nullptr;
3065  // Add this block to the list of successors for the block with the try
3066  // statement.
3067  addSuccessor(NewTryTerminatedBlock, ExceptBlock);
3068  }
3069  if (PrevSEHTryTerminatedBlock)
3070  addSuccessor(NewTryTerminatedBlock, PrevSEHTryTerminatedBlock);
3071  else
3072  addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
3073 
3074  // The code after the try is the implicit successor.
3075  Succ = SEHTrySuccessor;
3076 
3077  // Save the current "__try" context.
3078  SaveAndRestore<CFGBlock *> save_try(TryTerminatedBlock,
3079  NewTryTerminatedBlock);
3080  cfg->addTryDispatchBlock(TryTerminatedBlock);
3081 
3082  // Save the current value for the __leave target.
3083  // All __leaves should go to the code following the __try
3084  // (FIXME: or if the __try has a __finally, to the __finally.)
3085  SaveAndRestore<JumpTarget> save_break(SEHLeaveJumpTarget);
3086  SEHLeaveJumpTarget = JumpTarget(SEHTrySuccessor, ScopePos);
3087 
3088  assert(Terminator->getTryBlock() && "__try must contain a non-NULL body");
3089  Block = nullptr;
3090  return addStmt(Terminator->getTryBlock());
3091 }
3092 
3093 CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) {
3094  // Get the block of the labeled statement. Add it to our map.
3095  addStmt(L->getSubStmt());
3096  CFGBlock *LabelBlock = Block;
3097 
3098  if (!LabelBlock) // This can happen when the body is empty, i.e.
3099  LabelBlock = createBlock(); // scopes that only contains NullStmts.
3100 
3101  assert(LabelMap.find(L->getDecl()) == LabelMap.end() &&
3102  "label already in map");
3103  LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos);
3104 
3105  // Labels partition blocks, so this is the end of the basic block we were
3106  // processing (L is the block's label). Because this is label (and we have
3107  // already processed the substatement) there is no extra control-flow to worry
3108  // about.
3109  LabelBlock->setLabel(L);
3110  if (badCFG)
3111  return nullptr;
3112 
3113  // We set Block to NULL to allow lazy creation of a new block (if necessary);
3114  Block = nullptr;
3115 
3116  // This block is now the implicit successor of other blocks.
3117  Succ = LabelBlock;
3118 
3119  return LabelBlock;
3120 }
3121 
3122 CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) {
3123  CFGBlock *LastBlock = VisitNoRecurse(E, asc);
3124  for (const BlockDecl::Capture &CI : E->getBlockDecl()->captures()) {
3125  if (Expr *CopyExpr = CI.getCopyExpr()) {
3126  CFGBlock *Tmp = Visit(CopyExpr);
3127  if (Tmp)
3128  LastBlock = Tmp;
3129  }
3130  }
3131  return LastBlock;
3132 }
3133 
3134 CFGBlock *CFGBuilder::VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc) {
3135  CFGBlock *LastBlock = VisitNoRecurse(E, asc);
3137  et = E->capture_init_end(); it != et; ++it) {
3138  if (Expr *Init = *it) {
3139  CFGBlock *Tmp = Visit(Init);
3140  if (Tmp)
3141  LastBlock = Tmp;
3142  }
3143  }
3144  return LastBlock;
3145 }
3146 
3147 CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) {
3148  // Goto is a control-flow statement. Thus we stop processing the current
3149  // block and create a new one.
3150 
3151  Block = createBlock(false);
3152  Block->setTerminator(G);
3153 
3154  // If we already know the mapping to the label block add the successor now.
3155  LabelMapTy::iterator I = LabelMap.find(G->getLabel());
3156 
3157  if (I == LabelMap.end())
3158  // We will need to backpatch this block later.
3159  BackpatchBlocks.push_back(JumpSource(Block, ScopePos));
3160  else {
3161  JumpTarget JT = I->second;
3162  addAutomaticObjHandling(ScopePos, JT.scopePosition, G);
3163  addSuccessor(Block, JT.block);
3164  }
3165 
3166  return Block;
3167 }
3168 
3169 CFGBlock *CFGBuilder::VisitGCCAsmStmt(GCCAsmStmt *G, AddStmtChoice asc) {
3170  // Goto is a control-flow statement. Thus we stop processing the current
3171  // block and create a new one.
3172 
3173  if (!G->isAsmGoto())
3174  return VisitStmt(G, asc);
3175 
3176  if (Block) {
3177  Succ = Block;
3178  if (badCFG)
3179  return nullptr;
3180  }
3181  Block = createBlock();
3182  Block->setTerminator(G);
3183  // We will backpatch this block later for all the labels.
3184  BackpatchBlocks.push_back(JumpSource(Block, ScopePos));
3185  // Save "Succ" in BackpatchBlocks. In the backpatch processing, "Succ" is
3186  // used to avoid adding "Succ" again.
3187  BackpatchBlocks.push_back(JumpSource(Succ, ScopePos));
3188  return Block;
3189 }
3190 
3191 CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) {
3192  CFGBlock *LoopSuccessor = nullptr;
3193 
3194  // Save local scope position because in case of condition variable ScopePos
3195  // won't be restored when traversing AST.
3196  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3197 
3198  // Create local scope for init statement and possible condition variable.
3199  // Add destructor for init statement and condition variable.
3200  // Store scope position for continue statement.
3201  if (Stmt *Init = F->getInit())
3202  addLocalScopeForStmt(Init);
3203  LocalScope::const_iterator LoopBeginScopePos = ScopePos;
3204 
3205  if (VarDecl *VD = F->getConditionVariable())
3206  addLocalScopeForVarDecl(VD);
3207  LocalScope::const_iterator ContinueScopePos = ScopePos;
3208 
3209  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), F);
3210 
3211  addLoopExit(F);
3212 
3213  // "for" is a control-flow statement. Thus we stop processing the current
3214  // block.
3215  if (Block) {
3216  if (badCFG)
3217  return nullptr;
3218  LoopSuccessor = Block;
3219  } else
3220  LoopSuccessor = Succ;
3221 
3222  // Save the current value for the break targets.
3223  // All breaks should go to the code following the loop.
3224  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3225  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3226 
3227  CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
3228 
3229  // Now create the loop body.
3230  {
3231  assert(F->getBody());
3232 
3233  // Save the current values for Block, Succ, continue and break targets.
3234  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3235  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
3236 
3237  // Create an empty block to represent the transition block for looping back
3238  // to the head of the loop. If we have increment code, it will
3239  // go in this block as well.
3240  Block = Succ = TransitionBlock = createBlock(false);
3241  TransitionBlock->setLoopTarget(F);
3242 
3243  if (Stmt *I = F->getInc()) {
3244  // Generate increment code in its own basic block. This is the target of
3245  // continue statements.
3246  Succ = addStmt(I);
3247  }
3248 
3249  // Finish up the increment (or empty) block if it hasn't been already.
3250  if (Block) {
3251  assert(Block == Succ);
3252  if (badCFG)
3253  return nullptr;
3254  Block = nullptr;
3255  }
3256 
3257  // The starting block for the loop increment is the block that should
3258  // represent the 'loop target' for looping back to the start of the loop.
3259  ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
3260  ContinueJumpTarget.block->setLoopTarget(F);
3261 
3262  // Loop body should end with destructor of Condition variable (if any).
3263  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, F);
3264 
3265  // If body is not a compound statement create implicit scope
3266  // and add destructors.
3267  if (!isa<CompoundStmt>(F->getBody()))
3268  addLocalScopeAndDtors(F->getBody());
3269 
3270  // Now populate the body block, and in the process create new blocks as we
3271  // walk the body of the loop.
3272  BodyBlock = addStmt(F->getBody());
3273 
3274  if (!BodyBlock) {
3275  // In the case of "for (...;...;...);" we can have a null BodyBlock.
3276  // Use the continue jump target as the proxy for the body.
3277  BodyBlock = ContinueJumpTarget.block;
3278  }
3279  else if (badCFG)
3280  return nullptr;
3281  }
3282 
3283  // Because of short-circuit evaluation, the condition of the loop can span
3284  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3285  // evaluate the condition.
3286  CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
3287 
3288  do {
3289  Expr *C = F->getCond();
3290  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3291 
3292  // Specially handle logical operators, which have a slightly
3293  // more optimal CFG representation.
3294  if (BinaryOperator *Cond =
3295  dyn_cast_or_null<BinaryOperator>(C ? C->IgnoreParens() : nullptr))
3296  if (Cond->isLogicalOp()) {
3297  std::tie(EntryConditionBlock, ExitConditionBlock) =
3298  VisitLogicalOperator(Cond, F, BodyBlock, LoopSuccessor);
3299  break;
3300  }
3301 
3302  // The default case when not handling logical operators.
3303  EntryConditionBlock = ExitConditionBlock = createBlock(false);
3304  ExitConditionBlock->setTerminator(F);
3305 
3306  // See if this is a known constant.
3307  TryResult KnownVal(true);
3308 
3309  if (C) {
3310  // Now add the actual condition to the condition block.
3311  // Because the condition itself may contain control-flow, new blocks may
3312  // be created. Thus we update "Succ" after adding the condition.
3313  Block = ExitConditionBlock;
3314  EntryConditionBlock = addStmt(C);
3315 
3316  // If this block contains a condition variable, add both the condition
3317  // variable and initializer to the CFG.
3318  if (VarDecl *VD = F->getConditionVariable()) {
3319  if (Expr *Init = VD->getInit()) {
3320  autoCreateBlock();
3321  const DeclStmt *DS = F->getConditionVariableDeclStmt();
3322  assert(DS->isSingleDecl());
3323  findConstructionContexts(
3324  ConstructionContextLayer::create(cfg->getBumpVectorContext(), DS),
3325  Init);
3326  appendStmt(Block, DS);
3327  EntryConditionBlock = addStmt(Init);
3328  assert(Block == EntryConditionBlock);
3329  maybeAddScopeBeginForVarDecl(EntryConditionBlock, VD, C);
3330  }
3331  }
3332 
3333  if (Block && badCFG)
3334  return nullptr;
3335 
3336  KnownVal = tryEvaluateBool(C);
3337  }
3338 
3339  // Add the loop body entry as a successor to the condition.
3340  addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
3341  // Link up the condition block with the code that follows the loop. (the
3342  // false branch).
3343  addSuccessor(ExitConditionBlock,
3344  KnownVal.isTrue() ? nullptr : LoopSuccessor);
3345  } while (false);
3346 
3347  // Link up the loop-back block to the entry condition block.
3348  addSuccessor(TransitionBlock, EntryConditionBlock);
3349 
3350  // The condition block is the implicit successor for any code above the loop.
3351  Succ = EntryConditionBlock;
3352 
3353  // If the loop contains initialization, create a new block for those
3354  // statements. This block can also contain statements that precede the loop.
3355  if (Stmt *I = F->getInit()) {
3356  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3357  ScopePos = LoopBeginScopePos;
3358  Block = createBlock();
3359  return addStmt(I);
3360  }
3361 
3362  // There is no loop initialization. We are thus basically a while loop.
3363  // NULL out Block to force lazy block construction.
3364  Block = nullptr;
3365  Succ = EntryConditionBlock;
3366  return EntryConditionBlock;
3367 }
3368 
3369 CFGBlock *
3370 CFGBuilder::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *MTE,
3371  AddStmtChoice asc) {
3372  findConstructionContexts(
3373  ConstructionContextLayer::create(cfg->getBumpVectorContext(), MTE),
3374  MTE->getTemporary());
3375 
3376  return VisitStmt(MTE, asc);
3377 }
3378 
3379 CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) {
3380  if (asc.alwaysAdd(*this, M)) {
3381  autoCreateBlock();
3382  appendStmt(Block, M);
3383  }
3384  return Visit(M->getBase());
3385 }
3386 
3387 CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) {
3388  // Objective-C fast enumeration 'for' statements:
3389  // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC
3390  //
3391  // for ( Type newVariable in collection_expression ) { statements }
3392  //
3393  // becomes:
3394  //
3395  // prologue:
3396  // 1. collection_expression
3397  // T. jump to loop_entry
3398  // loop_entry:
3399  // 1. side-effects of element expression
3400  // 1. ObjCForCollectionStmt [performs binding to newVariable]
3401  // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil]
3402  // TB:
3403  // statements
3404  // T. jump to loop_entry
3405  // FB:
3406  // what comes after
3407  //
3408  // and
3409  //
3410  // Type existingItem;
3411  // for ( existingItem in expression ) { statements }
3412  //
3413  // becomes:
3414  //
3415  // the same with newVariable replaced with existingItem; the binding works
3416  // the same except that for one ObjCForCollectionStmt::getElement() returns
3417  // a DeclStmt and the other returns a DeclRefExpr.
3418 
3419  CFGBlock *LoopSuccessor = nullptr;
3420 
3421  if (Block) {
3422  if (badCFG)
3423  return nullptr;
3424  LoopSuccessor = Block;
3425  Block = nullptr;
3426  } else
3427  LoopSuccessor = Succ;
3428 
3429  // Build the condition blocks.
3430  CFGBlock *ExitConditionBlock = createBlock(false);
3431 
3432  // Set the terminator for the "exit" condition block.
3433  ExitConditionBlock->setTerminator(S);
3434 
3435  // The last statement in the block should be the ObjCForCollectionStmt, which
3436  // performs the actual binding to 'element' and determines if there are any
3437  // more items in the collection.
3438  appendStmt(ExitConditionBlock, S);
3439  Block = ExitConditionBlock;
3440 
3441  // Walk the 'element' expression to see if there are any side-effects. We
3442  // generate new blocks as necessary. We DON'T add the statement by default to
3443  // the CFG unless it contains control-flow.
3444  CFGBlock *EntryConditionBlock = Visit(S->getElement(),
3445  AddStmtChoice::NotAlwaysAdd);
3446  if (Block) {
3447  if (badCFG)
3448  return nullptr;
3449  Block = nullptr;
3450  }
3451 
3452  // The condition block is the implicit successor for the loop body as well as
3453  // any code above the loop.
3454  Succ = EntryConditionBlock;
3455 
3456  // Now create the true branch.
3457  {
3458  // Save the current values for Succ, continue and break targets.
3459  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3460  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3461  save_break(BreakJumpTarget);
3462 
3463  // Add an intermediate block between the BodyBlock and the
3464  // EntryConditionBlock to represent the "loop back" transition, for looping
3465  // back to the head of the loop.
3466  CFGBlock *LoopBackBlock = nullptr;
3467  Succ = LoopBackBlock = createBlock();
3468  LoopBackBlock->setLoopTarget(S);
3469 
3470  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3471  ContinueJumpTarget = JumpTarget(Succ, ScopePos);
3472 
3473  CFGBlock *BodyBlock = addStmt(S->getBody());
3474 
3475  if (!BodyBlock)
3476  BodyBlock = ContinueJumpTarget.block; // can happen for "for (X in Y) ;"
3477  else if (Block) {
3478  if (badCFG)
3479  return nullptr;
3480  }
3481 
3482  // This new body block is a successor to our "exit" condition block.
3483  addSuccessor(ExitConditionBlock, BodyBlock);
3484  }
3485 
3486  // Link up the condition block with the code that follows the loop.
3487  // (the false branch).
3488  addSuccessor(ExitConditionBlock, LoopSuccessor);
3489 
3490  // Now create a prologue block to contain the collection expression.
3491  Block = createBlock();
3492  return addStmt(S->getCollection());
3493 }
3494 
3495 CFGBlock *CFGBuilder::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) {
3496  // Inline the body.
3497  return addStmt(S->getSubStmt());
3498  // TODO: consider adding cleanups for the end of @autoreleasepool scope.
3499 }
3500 
3501 CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) {
3502  // FIXME: Add locking 'primitives' to CFG for @synchronized.
3503 
3504  // Inline the body.
3505  CFGBlock *SyncBlock = addStmt(S->getSynchBody());
3506 
3507  // The sync body starts its own basic block. This makes it a little easier
3508  // for diagnostic clients.
3509  if (SyncBlock) {
3510  if (badCFG)
3511  return nullptr;
3512 
3513  Block = nullptr;
3514  Succ = SyncBlock;
3515  }
3516 
3517  // Add the @synchronized to the CFG.
3518  autoCreateBlock();
3519  appendStmt(Block, S);
3520 
3521  // Inline the sync expression.
3522  return addStmt(S->getSynchExpr());
3523 }
3524 
3525 CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) {
3526  // FIXME
3527  return NYS();
3528 }
3529 
3530 CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) {
3531  autoCreateBlock();
3532 
3533  // Add the PseudoObject as the last thing.
3534  appendStmt(Block, E);
3535 
3536  CFGBlock *lastBlock = Block;
3537 
3538  // Before that, evaluate all of the semantics in order. In
3539  // CFG-land, that means appending them in reverse order.
3540  for (unsigned i = E->getNumSemanticExprs(); i != 0; ) {
3541  Expr *Semantic = E->getSemanticExpr(--i);
3542 
3543  // If the semantic is an opaque value, we're being asked to bind
3544  // it to its source expression.
3545  if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
3546  Semantic = OVE->getSourceExpr();
3547 
3548  if (CFGBlock *B = Visit(Semantic))
3549  lastBlock = B;
3550  }
3551 
3552  return lastBlock;
3553 }
3554 
3555 CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) {
3556  CFGBlock *LoopSuccessor = nullptr;
3557 
3558  // Save local scope position because in case of condition variable ScopePos
3559  // won't be restored when traversing AST.
3560  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3561 
3562  // Create local scope for possible condition variable.
3563  // Store scope position for continue statement.
3564  LocalScope::const_iterator LoopBeginScopePos = ScopePos;
3565  if (VarDecl *VD = W->getConditionVariable()) {
3566  addLocalScopeForVarDecl(VD);
3567  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3568  }
3569  addLoopExit(W);
3570 
3571  // "while" is a control-flow statement. Thus we stop processing the current
3572  // block.
3573  if (Block) {
3574  if (badCFG)
3575  return nullptr;
3576  LoopSuccessor = Block;
3577  Block = nullptr;
3578  } else {
3579  LoopSuccessor = Succ;
3580  }
3581 
3582  CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
3583 
3584  // Process the loop body.
3585  {
3586  assert(W->getBody());
3587 
3588  // Save the current values for Block, Succ, continue and break targets.
3589  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3590  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3591  save_break(BreakJumpTarget);
3592 
3593  // Create an empty block to represent the transition block for looping back
3594  // to the head of the loop.
3595  Succ = TransitionBlock = createBlock(false);
3596  TransitionBlock->setLoopTarget(W);
3597  ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos);
3598 
3599  // All breaks should go to the code following the loop.
3600  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3601 
3602  // Loop body should end with destructor of Condition variable (if any).
3603  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3604 
3605  // If body is not a compound statement create implicit scope
3606  // and add destructors.
3607  if (!isa<CompoundStmt>(W->getBody()))
3608  addLocalScopeAndDtors(W->getBody());
3609 
3610  // Create the body. The returned block is the entry to the loop body.
3611  BodyBlock = addStmt(W->getBody());
3612 
3613  if (!BodyBlock)
3614  BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;"
3615  else if (Block && badCFG)
3616  return nullptr;
3617  }
3618 
3619  // Because of short-circuit evaluation, the condition of the loop can span
3620  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3621  // evaluate the condition.
3622  CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
3623 
3624  do {
3625  Expr *C = W->getCond();
3626 
3627  // Specially handle logical operators, which have a slightly
3628  // more optimal CFG representation.
3629  if (BinaryOperator *Cond = dyn_cast<BinaryOperator>(C->IgnoreParens()))
3630  if (Cond->isLogicalOp()) {
3631  std::tie(EntryConditionBlock, ExitConditionBlock) =
3632  VisitLogicalOperator(Cond, W, BodyBlock, LoopSuccessor);
3633  break;
3634  }
3635 
3636  // The default case when not handling logical operators.
3637  ExitConditionBlock = createBlock(false);
3638  ExitConditionBlock->setTerminator(W);
3639 
3640  // Now add the actual condition to the condition block.
3641  // Because the condition itself may contain control-flow, new blocks may
3642  // be created. Thus we update "Succ" after adding the condition.
3643  Block = ExitConditionBlock;
3644  Block = EntryConditionBlock = addStmt(C);
3645 
3646  // If this block contains a condition variable, add both the condition
3647  // variable and initializer to the CFG.
3648  if (VarDecl *VD = W->getConditionVariable()) {
3649  if (Expr *Init = VD->getInit()) {
3650  autoCreateBlock();
3651  const DeclStmt *DS = W->getConditionVariableDeclStmt();
3652  assert(DS->isSingleDecl());
3653  findConstructionContexts(
3654  ConstructionContextLayer::create(cfg->getBumpVectorContext(),
3655  const_cast<DeclStmt *>(DS)),
3656  Init);
3657  appendStmt(Block, DS);
3658  EntryConditionBlock = addStmt(Init);
3659  assert(Block == EntryConditionBlock);
3660  maybeAddScopeBeginForVarDecl(EntryConditionBlock, VD, C);
3661  }
3662  }
3663 
3664  if (Block && badCFG)
3665  return nullptr;
3666 
3667  // See if this is a known constant.
3668  const TryResult& KnownVal = tryEvaluateBool(C);
3669 
3670  // Add the loop body entry as a successor to the condition.
3671  addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
3672  // Link up the condition block with the code that follows the loop. (the
3673  // false branch).
3674  addSuccessor(ExitConditionBlock,
3675  KnownVal.isTrue() ? nullptr : LoopSuccessor);
3676  } while(false);
3677 
3678  // Link up the loop-back block to the entry condition block.
3679  addSuccessor(TransitionBlock, EntryConditionBlock);
3680 
3681  // There can be no more statements in the condition block since we loop back
3682  // to this block. NULL out Block to force lazy creation of another block.
3683  Block = nullptr;
3684 
3685  // Return the condition block, which is the dominating block for the loop.
3686  Succ = EntryConditionBlock;
3687  return EntryConditionBlock;
3688 }
3689 
3690 CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) {
3691  // FIXME: For now we pretend that @catch and the code it contains does not
3692  // exit.
3693  return Block;
3694 }
3695 
3696 CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) {
3697  // FIXME: This isn't complete. We basically treat @throw like a return
3698  // statement.
3699 
3700  // If we were in the middle of a block we stop processing that block.
3701  if (badCFG)
3702  return nullptr;
3703 
3704  // Create the new block.
3705  Block = createBlock(false);
3706 
3707  // The Exit block is the only successor.
3708  addSuccessor(Block, &cfg->getExit());
3709 
3710  // Add the statement to the block. This may create new blocks if S contains
3711  // control-flow (short-circuit operations).
3712  return VisitStmt(S, AddStmtChoice::AlwaysAdd);
3713 }
3714 
3715 CFGBlock *CFGBuilder::VisitObjCMessageExpr(ObjCMessageExpr *ME,
3716  AddStmtChoice asc) {
3717  findConstructionContextsForArguments(ME);
3718 
3719  autoCreateBlock();
3720  appendObjCMessage(Block, ME);
3721 
3722  return VisitChildren(ME);
3723 }
3724 
3725 CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) {
3726  // If we were in the middle of a block we stop processing that block.
3727  if (badCFG)
3728  return nullptr;
3729 
3730  // Create the new block.
3731  Block = createBlock(false);
3732 
3733  if (TryTerminatedBlock)
3734  // The current try statement is the only successor.
3735  addSuccessor(Block, TryTerminatedBlock);
3736  else
3737  // otherwise the Exit block is the only successor.
3738  addSuccessor(Block, &cfg->getExit());
3739 
3740  // Add the statement to the block. This may create new blocks if S contains
3741  // control-flow (short-circuit operations).
3742  return VisitStmt(T, AddStmtChoice::AlwaysAdd);
3743 }
3744 
3745 CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) {
3746  CFGBlock *LoopSuccessor = nullptr;
3747 
3748  addLoopExit(D);
3749 
3750  // "do...while" is a control-flow statement. Thus we stop processing the
3751  // current block.
3752  if (Block) {
3753  if (badCFG)
3754  return nullptr;
3755  LoopSuccessor = Block;
3756  } else
3757  LoopSuccessor = Succ;
3758 
3759  // Because of short-circuit evaluation, the condition of the loop can span
3760  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3761  // evaluate the condition.
3762  CFGBlock *ExitConditionBlock = createBlock(false);
3763  CFGBlock *EntryConditionBlock = ExitConditionBlock;
3764 
3765  // Set the terminator for the "exit" condition block.
3766  ExitConditionBlock->setTerminator(D);
3767 
3768  // Now add the actual condition to the condition block. Because the condition
3769  // itself may contain control-flow, new blocks may be created.
3770  if (Stmt *C = D->getCond()) {
3771  Block = ExitConditionBlock;
3772  EntryConditionBlock = addStmt(C);
3773  if (Block) {
3774  if (badCFG)
3775  return nullptr;
3776  }
3777  }
3778 
3779  // The condition block is the implicit successor for the loop body.
3780  Succ = EntryConditionBlock;
3781 
3782  // See if this is a known constant.
3783  const TryResult &KnownVal = tryEvaluateBool(D->getCond());
3784 
3785  // Process the loop body.
3786  CFGBlock *BodyBlock = nullptr;
3787  {
3788  assert(D->getBody());
3789 
3790  // Save the current values for Block, Succ, and continue and break targets
3791  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3792  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3793  save_break(BreakJumpTarget);
3794 
3795  // All continues within this loop should go to the condition block
3796  ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos);
3797 
3798  // All breaks should go to the code following the loop.
3799  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3800 
3801  // NULL out Block to force lazy instantiation of blocks for the body.
3802  Block = nullptr;
3803 
3804  // If body is not a compound statement create implicit scope
3805  // and add destructors.
3806  if (!isa<CompoundStmt>(D->getBody()))
3807  addLocalScopeAndDtors(D->getBody());
3808 
3809  // Create the body. The returned block is the entry to the loop body.
3810  BodyBlock = addStmt(D->getBody());
3811 
3812  if (!BodyBlock)
3813  BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)"
3814  else if (Block) {
3815  if (badCFG)
3816  return nullptr;
3817  }
3818 
3819  // Add an intermediate block between the BodyBlock and the
3820  // ExitConditionBlock to represent the "loop back" transition. Create an
3821  // empty block to represent the transition block for looping back to the
3822  // head of the loop.
3823  // FIXME: Can we do this more efficiently without adding another block?
3824  Block = nullptr;
3825  Succ = BodyBlock;
3826  CFGBlock *LoopBackBlock = createBlock();
3827  LoopBackBlock->setLoopTarget(D);
3828 
3829  if (!KnownVal.isFalse())
3830  // Add the loop body entry as a successor to the condition.
3831  addSuccessor(ExitConditionBlock, LoopBackBlock);
3832  else
3833  addSuccessor(ExitConditionBlock, nullptr);
3834  }
3835 
3836  // Link up the condition block with the code that follows the loop.
3837  // (the false branch).
3838  addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
3839 
3840  // There can be no more statements in the body block(s) since we loop back to
3841  // the body. NULL out Block to force lazy creation of another block.
3842  Block = nullptr;
3843 
3844  // Return the loop body, which is the dominating block for the loop.
3845  Succ = BodyBlock;
3846  return BodyBlock;
3847 }
3848 
3849 CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) {
3850  // "continue" is a control-flow statement. Thus we stop processing the
3851  // current block.
3852  if (badCFG)
3853  return nullptr;
3854 
3855  // Now create a new block that ends with the continue statement.
3856  Block = createBlock(false);
3857  Block->setTerminator(C);
3858 
3859  // If there is no target for the continue, then we are looking at an
3860  // incomplete AST. This means the CFG cannot be constructed.
3861  if (ContinueJumpTarget.block) {
3862  addAutomaticObjHandling(ScopePos, ContinueJumpTarget.scopePosition, C);
3863  addSuccessor(Block, ContinueJumpTarget.block);
3864  } else
3865  badCFG = true;
3866 
3867  return Block;
3868 }
3869 
3870 CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
3871  AddStmtChoice asc) {
3872  if (asc.alwaysAdd(*this, E)) {
3873  autoCreateBlock();
3874  appendStmt(Block, E);
3875  }
3876 
3877  // VLA types have expressions that must be evaluated.
3878  CFGBlock *lastBlock = Block;
3879 
3880  if (E->isArgumentType()) {
3881  for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr());
3882  VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr()))
3883  lastBlock = addStmt(VA->getSizeExpr());
3884  }
3885  return lastBlock;
3886 }
3887 
3888 /// VisitStmtExpr - Utility method to handle (nested) statement
3889 /// expressions (a GCC extension).
3890 CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) {
3891  if (asc.alwaysAdd(*this, SE)) {
3892  autoCreateBlock();
3893  appendStmt(Block, SE);
3894  }
3895  return VisitCompoundStmt(SE->getSubStmt());
3896 }
3897 
3898 CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) {
3899  // "switch" is a control-flow statement. Thus we stop processing the current
3900  // block.
3901  CFGBlock *SwitchSuccessor = nullptr;
3902 
3903  // Save local scope position because in case of condition variable ScopePos
3904  // won't be restored when traversing AST.
3905  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3906 
3907  // Create local scope for C++17 switch init-stmt if one exists.
3908  if (Stmt *Init = Terminator->getInit())
3909  addLocalScopeForStmt(Init);
3910 
3911  // Create local scope for possible condition variable.
3912  // Store scope position. Add implicit destructor.
3913  if (VarDecl *VD = Terminator->getConditionVariable())
3914  addLocalScopeForVarDecl(VD);
3915 
3916  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), Terminator);
3917 
3918  if (Block) {
3919  if (badCFG)
3920  return nullptr;
3921  SwitchSuccessor = Block;
3922  } else SwitchSuccessor = Succ;
3923 
3924  // Save the current "switch" context.
3925  SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock),
3926  save_default(DefaultCaseBlock);
3927  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3928 
3929  // Set the "default" case to be the block after the switch statement. If the
3930  // switch statement contains a "default:", this value will be overwritten with
3931  // the block for that code.
3932  DefaultCaseBlock = SwitchSuccessor;
3933 
3934  // Create a new block that will contain the switch statement.
3935  SwitchTerminatedBlock = createBlock(false);
3936 
3937  // Now process the switch body. The code after the switch is the implicit
3938  // successor.
3939  Succ = SwitchSuccessor;
3940  BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos);
3941 
3942  // When visiting the body, the case statements should automatically get linked
3943  // up to the switch. We also don't keep a pointer to the body, since all
3944  // control-flow from the switch goes to case/default statements.
3945  assert(Terminator->getBody() && "switch must contain a non-NULL body");
3946  Block = nullptr;
3947 
3948  // For pruning unreachable case statements, save the current state
3949  // for tracking the condition value.
3950  SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered,
3951  false);
3952 
3953  // Determine if the switch condition can be explicitly evaluated.
3954  assert(Terminator->getCond() && "switch condition must be non-NULL");
3956  bool b = tryEvaluate(Terminator->getCond(), result);
3957  SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond,
3958  b ? &result : nullptr);
3959 
3960  // If body is not a compound statement create implicit scope
3961  // and add destructors.
3962  if (!isa<CompoundStmt>(Terminator->getBody()))
3963  addLocalScopeAndDtors(Terminator->getBody());
3964 
3965  addStmt(Terminator->getBody());
3966  if (Block) {
3967  if (badCFG)
3968  return nullptr;
3969  }
3970 
3971  // If we have no "default:" case, the default transition is to the code
3972  // following the switch body. Moreover, take into account if all the
3973  // cases of a switch are covered (e.g., switching on an enum value).
3974  //
3975  // Note: We add a successor to a switch that is considered covered yet has no
3976  // case statements if the enumeration has no enumerators.
3977  bool SwitchAlwaysHasSuccessor = false;
3978  SwitchAlwaysHasSuccessor |= switchExclusivelyCovered;
3979  SwitchAlwaysHasSuccessor |= Terminator->isAllEnumCasesCovered() &&
3980  Terminator->getSwitchCaseList();
3981  addSuccessor(SwitchTerminatedBlock, DefaultCaseBlock,
3982  !SwitchAlwaysHasSuccessor);
3983 
3984  // Add the terminator and condition in the switch block.
3985  SwitchTerminatedBlock->setTerminator(Terminator);
3986  Block = SwitchTerminatedBlock;
3987  CFGBlock *LastBlock = addStmt(Terminator->getCond());
3988 
3989  // If the SwitchStmt contains a condition variable, add both the
3990  // SwitchStmt and the condition variable initialization to the CFG.
3991  if (VarDecl *VD = Terminator->getConditionVariable()) {
3992  if (Expr *Init = VD->getInit()) {
3993  autoCreateBlock();
3994  appendStmt(Block, Terminator->getConditionVariableDeclStmt());
3995  LastBlock = addStmt(Init);
3996  maybeAddScopeBeginForVarDecl(LastBlock, VD, Init);
3997  }
3998  }
3999 
4000  // Finally, if the SwitchStmt contains a C++17 init-stmt, add it to the CFG.
4001  if (Stmt *Init = Terminator->getInit()) {
4002  autoCreateBlock();
4003  LastBlock = addStmt(Init);
4004  }
4005 
4006  return LastBlock;
4007 }
4008 
4009 static bool shouldAddCase(bool &switchExclusivelyCovered,
4010  const Expr::EvalResult *switchCond,
4011  const CaseStmt *CS,
4012  ASTContext &Ctx) {
4013  if (!switchCond)
4014  return true;
4015 
4016  bool addCase = false;
4017 
4018  if (!switchExclusivelyCovered) {
4019  if (switchCond->Val.isInt()) {
4020  // Evaluate the LHS of the case value.
4021  const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx);
4022  const llvm::APSInt &condInt = switchCond->Val.getInt();
4023 
4024  if (condInt == lhsInt) {
4025  addCase = true;
4026  switchExclusivelyCovered = true;
4027  }
4028  else if (condInt > lhsInt) {
4029  if (const Expr *RHS = CS->getRHS()) {
4030  // Evaluate the RHS of the case value.
4031  const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx);
4032  if (V2 >= condInt) {
4033  addCase = true;
4034  switchExclusivelyCovered = true;
4035  }
4036  }
4037  }
4038  }
4039  else
4040  addCase = true;
4041  }
4042  return addCase;
4043 }
4044 
4045 CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) {
4046  // CaseStmts are essentially labels, so they are the first statement in a
4047  // block.
4048  CFGBlock *TopBlock = nullptr, *LastBlock = nullptr;
4049 
4050  if (Stmt *Sub = CS->getSubStmt()) {
4051  // For deeply nested chains of CaseStmts, instead of doing a recursion
4052  // (which can blow out the stack), manually unroll and create blocks
4053  // along the way.
4054  while (isa<CaseStmt>(Sub)) {
4055  CFGBlock *currentBlock = createBlock(false);
4056  currentBlock->setLabel(CS);
4057 
4058  if (TopBlock)
4059  addSuccessor(LastBlock, currentBlock);
4060  else
4061  TopBlock = currentBlock;
4062 
4063  addSuccessor(SwitchTerminatedBlock,
4064  shouldAddCase(switchExclusivelyCovered, switchCond,
4065  CS, *Context)
4066  ? currentBlock : nullptr);
4067 
4068  LastBlock = currentBlock;
4069  CS = cast<CaseStmt>(Sub);
4070  Sub = CS->getSubStmt();
4071  }
4072 
4073  addStmt(Sub);
4074  }
4075 
4076  CFGBlock *CaseBlock = Block;
4077  if (!CaseBlock)
4078  CaseBlock = createBlock();
4079 
4080  // Cases statements partition blocks, so this is the top of the basic block we
4081  // were processing (the "case XXX:" is the label).
4082  CaseBlock->setLabel(CS);
4083 
4084  if (badCFG)
4085  return nullptr;
4086 
4087  // Add this block to the list of successors for the block with the switch
4088  // statement.
4089  assert(SwitchTerminatedBlock);
4090  addSuccessor(SwitchTerminatedBlock, CaseBlock,
4091  shouldAddCase(switchExclusivelyCovered, switchCond,
4092  CS, *Context));
4093 
4094  // We set Block to NULL to allow lazy creation of a new block (if necessary)
4095  Block = nullptr;
4096 
4097  if (TopBlock) {
4098  addSuccessor(LastBlock, CaseBlock);
4099  Succ = TopBlock;
4100  } else {
4101  // This block is now the implicit successor of other blocks.
4102  Succ = CaseBlock;
4103  }
4104 
4105  return Succ;
4106 }
4107 
4108 CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) {
4109  if (Terminator->getSubStmt())
4110  addStmt(Terminator->getSubStmt());
4111 
4112  DefaultCaseBlock = Block;
4113 
4114  if (!DefaultCaseBlock)
4115  DefaultCaseBlock = createBlock();
4116 
4117  // Default statements partition blocks, so this is the top of the basic block
4118  // we were processing (the "default:" is the label).
4119  DefaultCaseBlock->setLabel(Terminator);
4120 
4121  if (badCFG)
4122  return nullptr;
4123 
4124  // Unlike case statements, we don't add the default block to the successors
4125  // for the switch statement immediately. This is done when we finish
4126  // processing the switch statement. This allows for the default case
4127  // (including a fall-through to the code after the switch statement) to always
4128  // be the last successor of a switch-terminated block.
4129 
4130  // We set Block to NULL to allow lazy creation of a new block (if necessary)
4131  Block = nullptr;
4132 
4133  // This block is now the implicit successor of other blocks.
4134  Succ = DefaultCaseBlock;
4135 
4136  return DefaultCaseBlock;
4137 }
4138 
4139 CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) {
4140  // "try"/"catch" is a control-flow statement. Thus we stop processing the
4141  // current block.
4142  CFGBlock *TrySuccessor = nullptr;
4143 
4144  if (Block) {
4145  if (badCFG)
4146  return nullptr;
4147  TrySuccessor = Block;
4148  } else TrySuccessor = Succ;
4149 
4150  CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock;
4151 
4152  // Create a new block that will contain the try statement.
4153  CFGBlock *NewTryTerminatedBlock = createBlock(false);
4154  // Add the terminator in the try block.
4155  NewTryTerminatedBlock->setTerminator(Terminator);
4156 
4157  bool HasCatchAll = false;
4158  for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) {
4159  // The code after the try is the implicit successor.
4160  Succ = TrySuccessor;
4161  CXXCatchStmt *CS = Terminator->getHandler(h);
4162  if (CS->getExceptionDecl() == nullptr) {
4163  HasCatchAll = true;
4164  }
4165  Block = nullptr;
4166  CFGBlock *CatchBlock = VisitCXXCatchStmt(CS);
4167  if (!CatchBlock)
4168  return nullptr;
4169  // Add this block to the list of successors for the block with the try
4170  // statement.
4171  addSuccessor(NewTryTerminatedBlock, CatchBlock);
4172  }
4173  if (!HasCatchAll) {
4174  if (PrevTryTerminatedBlock)
4175  addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock);
4176  else
4177  addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
4178  }
4179 
4180  // The code after the try is the implicit successor.
4181  Succ = TrySuccessor;
4182 
4183  // Save the current "try" context.
4184  SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock);
4185  cfg->addTryDispatchBlock(TryTerminatedBlock);
4186 
4187  assert(Terminator->getTryBlock() && "try must contain a non-NULL body");
4188  Block = nullptr;
4189  return addStmt(Terminator->getTryBlock());
4190 }
4191 
4192 CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) {
4193  // CXXCatchStmt are treated like labels, so they are the first statement in a
4194  // block.
4195 
4196  // Save local scope position because in case of exception variable ScopePos
4197  // won't be restored when traversing AST.
4198  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
4199 
4200  // Create local scope for possible exception variable.
4201  // Store scope position. Add implicit destructor.
4202  if (VarDecl *VD = CS->getExceptionDecl()) {
4203  LocalScope::const_iterator BeginScopePos = ScopePos;
4204  addLocalScopeForVarDecl(VD);
4205  addAutomaticObjHandling(ScopePos, BeginScopePos, CS);
4206  }
4207 
4208  if (CS->getHandlerBlock())
4209  addStmt(CS->getHandlerBlock());
4210 
4211  CFGBlock *CatchBlock = Block;
4212  if (!CatchBlock)
4213  CatchBlock = createBlock();
4214 
4215  // CXXCatchStmt is more than just a label. They have semantic meaning
4216  // as well, as they implicitly "initialize" the catch variable. Add
4217  // it to the CFG as a CFGElement so that the control-flow of these
4218  // semantics gets captured.
4219  appendStmt(CatchBlock, CS);
4220 
4221  // Also add the CXXCatchStmt as a label, to mirror handling of regular
4222  // labels.
4223  CatchBlock->setLabel(CS);
4224 
4225  // Bail out if the CFG is bad.
4226  if (badCFG)
4227  return nullptr;
4228 
4229  // We set Block to NULL to allow lazy creation of a new block (if necessary)
4230  Block = nullptr;
4231 
4232  return CatchBlock;
4233 }
4234 
4235 CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) {
4236  // C++0x for-range statements are specified as [stmt.ranged]:
4237  //
4238  // {
4239  // auto && __range = range-init;
4240  // for ( auto __begin = begin-expr,
4241  // __end = end-expr;
4242  // __begin != __end;
4243  // ++__begin ) {
4244  // for-range-declaration = *__begin;
4245  // statement
4246  // }
4247  // }
4248 
4249  // Save local scope position before the addition of the implicit variables.
4250  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
4251 
4252  // Create local scopes and destructors for range, begin and end variables.
4253  if (Stmt *Range = S->getRangeStmt())
4254  addLocalScopeForStmt(Range);
4255  if (Stmt *Begin = S->getBeginStmt())
4256  addLocalScopeForStmt(Begin);
4257  if (Stmt *End = S->getEndStmt())
4258  addLocalScopeForStmt(End);
4259  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), S);
4260 
4261  LocalScope::const_iterator ContinueScopePos = ScopePos;
4262 
4263  // "for" is a control-flow statement. Thus we stop processing the current
4264  // block.
4265  CFGBlock *LoopSuccessor = nullptr;
4266  if (Block) {
4267  if (badCFG)
4268  return nullptr;
4269  LoopSuccessor = Block;
4270  } else
4271  LoopSuccessor = Succ;
4272 
4273  // Save the current value for the break targets.
4274  // All breaks should go to the code following the loop.
4275  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
4276  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
4277 
4278  // The block for the __begin != __end expression.
4279  CFGBlock *ConditionBlock = createBlock(false);
4280  ConditionBlock->setTerminator(S);
4281 
4282  // Now add the actual condition to the condition block.
4283  if (Expr *C = S->getCond()) {
4284  Block = ConditionBlock;
4285  CFGBlock *BeginConditionBlock = addStmt(C);
4286  if (badCFG)
4287  return nullptr;
4288  assert(BeginConditionBlock == ConditionBlock &&
4289  "condition block in for-range was unexpectedly complex");
4290  (void)BeginConditionBlock;
4291  }
4292 
4293  // The condition block is the implicit successor for the loop body as well as
4294  // any code above the loop.
4295  Succ = ConditionBlock;
4296 
4297  // See if this is a known constant.
4298  TryResult KnownVal(true);
4299 
4300  if (S->getCond())
4301  KnownVal = tryEvaluateBool(S->getCond());
4302 
4303  // Now create the loop body.
4304  {
4305  assert(S->getBody());
4306 
4307  // Save the current values for Block, Succ, and continue targets.
4308  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
4309  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
4310 
4311  // Generate increment code in its own basic block. This is the target of
4312  // continue statements.
4313  Block = nullptr;
4314  Succ = addStmt(S->getInc());
4315  if (badCFG)
4316  return nullptr;
4317  ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
4318 
4319  // The starting block for the loop increment is the block that should
4320  // represent the 'loop target' for looping back to the start of the loop.
4321  ContinueJumpTarget.block->setLoopTarget(S);
4322 
4323  // Finish up the increment block and prepare to start the loop body.
4324  assert(Block);
4325  if (badCFG)
4326  return nullptr;
4327  Block = nullptr;
4328 
4329  // Add implicit scope and dtors for loop variable.
4330  addLocalScopeAndDtors(S->getLoopVarStmt());
4331 
4332  // Populate a new block to contain the loop body and loop variable.
4333  addStmt(S->getBody());
4334  if (badCFG)
4335  return nullptr;
4336  CFGBlock *LoopVarStmtBlock = addStmt(S->getLoopVarStmt());
4337  if (badCFG)
4338  return nullptr;
4339 
4340  // This new body block is a successor to our condition block.
4341  addSuccessor(ConditionBlock,
4342  KnownVal.isFalse() ? nullptr : LoopVarStmtBlock);
4343  }
4344 
4345  // Link up the condition block with the code that follows the loop (the
4346  // false branch).
4347  addSuccessor(ConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
4348 
4349  // Add the initialization statements.
4350  Block = createBlock();
4351  addStmt(S->getBeginStmt());
4352  addStmt(S->getEndStmt());
4353  CFGBlock *Head = addStmt(S->getRangeStmt());
4354  if (S->getInit())
4355  Head = addStmt(S->getInit());
4356  return Head;
4357 }
4358 
4359 CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E,
4360  AddStmtChoice asc) {
4361  if (BuildOpts.AddTemporaryDtors) {
4362  // If adding implicit destructors visit the full expression for adding
4363  // destructors of temporaries.
4364  TempDtorContext Context;
4365  VisitForTemporaryDtors(E->getSubExpr(), false, Context);
4366 
4367  // Full expression has to be added as CFGStmt so it will be sequenced
4368  // before destructors of it's temporaries.
4369  asc = asc.withAlwaysAdd(true);
4370  }
4371  return Visit(E->getSubExpr(), asc);
4372 }
4373 
4374 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
4375  AddStmtChoice asc) {
4376  if (asc.alwaysAdd(*this, E)) {
4377  autoCreateBlock();
4378  appendStmt(Block, E);
4379 
4380  findConstructionContexts(
4381  ConstructionContextLayer::create(cfg->getBumpVectorContext(), E),
4382  E->getSubExpr());
4383 
4384  // We do not want to propagate the AlwaysAdd property.
4385  asc = asc.withAlwaysAdd(false);
4386  }
4387  return Visit(E->getSubExpr(), asc);
4388 }
4389 
4390 CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C,
4391  AddStmtChoice asc) {
4392  // If the constructor takes objects as arguments by value, we need to properly
4393  // construct these objects. Construction contexts we find here aren't for the
4394  // constructor C, they're for its arguments only.
4395  findConstructionContextsForArguments(C);
4396 
4397  autoCreateBlock();
4398  appendConstructor(Block, C);
4399 
4400  return VisitChildren(C);
4401 }
4402 
4403 CFGBlock *CFGBuilder::VisitCXXNewExpr(CXXNewExpr *NE,
4404  AddStmtChoice asc) {
4405  autoCreateBlock();
4406  appendStmt(Block, NE);
4407 
4408  findConstructionContexts(
4409  ConstructionContextLayer::create(cfg->getBumpVectorContext(), NE),
4410  const_cast<CXXConstructExpr *>(NE->getConstructExpr()));
4411 
4412  if (NE->getInitializer())
4413  Block = Visit(NE->getInitializer());
4414 
4415  if (BuildOpts.AddCXXNewAllocator)
4416  appendNewAllocator(Block, NE);
4417 
4418  if (NE->isArray() && *NE->getArraySize())
4419  Block = Visit(*NE->getArraySize());
4420 
4422  E = NE->placement_arg_end(); I != E; ++I)
4423  Block = Visit(*I);
4424 
4425  return Block;
4426 }
4427 
4428 CFGBlock *CFGBuilder::VisitCXXDeleteExpr(CXXDeleteExpr *DE,
4429  AddStmtChoice asc) {
4430  autoCreateBlock();
4431  appendStmt(Block, DE);
4432  QualType DTy = DE->getDestroyedType();
4433  if (!DTy.isNull()) {
4434  DTy = DTy.getNonReferenceType();
4435  CXXRecordDecl *RD = Context->getBaseElementType(DTy)->getAsCXXRecordDecl();
4436  if (RD) {
4437  if (RD->isCompleteDefinition() && !RD->hasTrivialDestructor())
4438  appendDeleteDtor(Block, RD, DE);
4439  }
4440  }
4441 
4442  return VisitChildren(DE);
4443 }
4444 
4445 CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
4446  AddStmtChoice asc) {
4447  if (asc.alwaysAdd(*this, E)) {
4448  autoCreateBlock();
4449  appendStmt(Block, E);
4450  // We do not want to propagate the AlwaysAdd property.
4451  asc = asc.withAlwaysAdd(false);
4452  }
4453  return Visit(E->getSubExpr(), asc);
4454 }
4455 
4456 CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
4457  AddStmtChoice asc) {
4458  // If the constructor takes objects as arguments by value, we need to properly
4459  // construct these objects. Construction contexts we find here aren't for the
4460  // constructor C, they're for its arguments only.
4461  findConstructionContextsForArguments(C);
4462 
4463  autoCreateBlock();
4464  appendConstructor(Block, C);
4465  return VisitChildren(C);
4466 }
4467 
4468 CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E,
4469  AddStmtChoice asc) {
4470  if (asc.alwaysAdd(*this, E)) {
4471  autoCreateBlock();
4472  appendStmt(Block, E);
4473  }
4474  return Visit(E->getSubExpr(), AddStmtChoice());
4475 }
4476 
4477 CFGBlock *CFGBuilder::VisitConstantExpr(ConstantExpr *E, AddStmtChoice asc) {
4478  return Visit(E->getSubExpr(), AddStmtChoice());
4479 }
4480 
4481 CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) {
4482  // Lazily create the indirect-goto dispatch block if there isn't one already.
4483  CFGBlock *IBlock = cfg->getIndirectGotoBlock();
4484 
4485  if (!IBlock) {
4486  IBlock = createBlock(false);
4487  cfg->setIndirectGotoBlock(IBlock);
4488  }
4489 
4490  // IndirectGoto is a control-flow statement. Thus we stop processing the
4491  // current block and create a new one.
4492  if (badCFG)
4493  return nullptr;
4494 
4495  Block = createBlock(false);
4496  Block->setTerminator(I);
4497  addSuccessor(Block, IBlock);
4498  return addStmt(I->getTarget());
4499 }
4500 
4501 CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary,
4502  TempDtorContext &Context) {
4503  assert(BuildOpts.AddImplicitDtors && BuildOpts.AddTemporaryDtors);
4504 
4505 tryAgain:
4506  if (!E) {
4507  badCFG = true;
4508  return nullptr;
4509  }
4510  switch (E->getStmtClass()) {
4511  default:
4512  return VisitChildrenForTemporaryDtors(E, Context);
4513 
4514  case Stmt::BinaryOperatorClass:
4515  return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E),
4516  Context);
4517 
4518  case Stmt::CXXBindTemporaryExprClass:
4519  return VisitCXXBindTemporaryExprForTemporaryDtors(
4520  cast<CXXBindTemporaryExpr>(E), BindToTemporary, Context);
4521 
4522  case Stmt::BinaryConditionalOperatorClass:
4523  case Stmt::ConditionalOperatorClass:
4524  return VisitConditionalOperatorForTemporaryDtors(
4525  cast<AbstractConditionalOperator>(E), BindToTemporary, Context);
4526 
4527  case Stmt::ImplicitCastExprClass:
4528  // For implicit cast we want BindToTemporary to be passed further.
4529  E = cast<CastExpr>(E)->getSubExpr();
4530  goto tryAgain;
4531 
4532  case Stmt::CXXFunctionalCastExprClass:
4533  // For functional cast we want BindToTemporary to be passed further.
4534  E = cast<CXXFunctionalCastExpr>(E)->getSubExpr();
4535  goto tryAgain;
4536 
4537  case Stmt::ConstantExprClass:
4538  E = cast<ConstantExpr>(E)->getSubExpr();
4539  goto tryAgain;
4540 
4541  case Stmt::ParenExprClass:
4542  E = cast<ParenExpr>(E)->getSubExpr();
4543  goto tryAgain;
4544 
4545  case Stmt::MaterializeTemporaryExprClass: {
4546  const MaterializeTemporaryExpr* MTE = cast<MaterializeTemporaryExpr>(E);
4547  BindToTemporary = (MTE->getStorageDuration() != SD_FullExpression);
4548  SmallVector<const Expr *, 2> CommaLHSs;
4550  // Find the expression whose lifetime needs to be extended.
4551  E = const_cast<Expr *>(
4552  cast<MaterializeTemporaryExpr>(E)
4553  ->GetTemporaryExpr()
4554  ->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments));
4555  // Visit the skipped comma operator left-hand sides for other temporaries.
4556  for (const Expr *CommaLHS : CommaLHSs) {
4557  VisitForTemporaryDtors(const_cast<Expr *>(CommaLHS),
4558  /*BindToTemporary=*/false, Context);
4559  }
4560  goto tryAgain;
4561  }
4562 
4563  case Stmt::BlockExprClass:
4564  // Don't recurse into blocks; their subexpressions don't get evaluated
4565  // here.
4566  return Block;
4567 
4568  case Stmt::LambdaExprClass: {
4569  // For lambda expressions, only recurse into the capture initializers,
4570  // and not the body.
4571  auto *LE = cast<LambdaExpr>(E);
4572  CFGBlock *B = Block;
4573  for (Expr *Init : LE->capture_inits()) {
4574  if (Init) {
4575  if (CFGBlock *R = VisitForTemporaryDtors(
4576  Init, /*BindToTemporary=*/false, Context))
4577  B = R;
4578  }
4579  }
4580  return B;
4581  }
4582 
4583  case Stmt::CXXDefaultArgExprClass:
4584  E = cast<CXXDefaultArgExpr>(E)->getExpr();
4585  goto tryAgain;
4586 
4587  case Stmt::CXXDefaultInitExprClass:
4588  E = cast<CXXDefaultInitExpr>(E)->getExpr();
4589  goto tryAgain;
4590  }
4591 }
4592 
4593 CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E,
4594  TempDtorContext &Context) {
4595  if (isa<LambdaExpr>(E)) {
4596  // Do not visit the children of lambdas; they have their own CFGs.
4597  return Block;
4598  }
4599 
4600  // When visiting children for destructors we want to visit them in reverse
4601  // order that they will appear in the CFG. Because the CFG is built
4602  // bottom-up, this means we visit them in their natural order, which
4603  // reverses them in the CFG.
4604  CFGBlock *B = Block;
4605  for (Stmt *Child : E->children())
4606  if (Child)
4607  if (CFGBlock *R = VisitForTemporaryDtors(Child, false, Context))
4608  B = R;
4609 
4610  return B;
4611 }
4612 
4613 CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(
4614  BinaryOperator *E, TempDtorContext &Context) {
4615  if (E->isLogicalOp()) {
4616  VisitForTemporaryDtors(E->getLHS(), false, Context);
4617  TryResult RHSExecuted = tryEvaluateBool(E->getLHS());
4618  if (RHSExecuted.isKnown() && E->getOpcode() == BO_LOr)
4619  RHSExecuted.negate();
4620 
4621  // We do not know at CFG-construction time whether the right-hand-side was
4622  // executed, thus we add a branch node that depends on the temporary
4623  // constructor call.
4624  TempDtorContext RHSContext(
4625  bothKnownTrue(Context.KnownExecuted, RHSExecuted));
4626  VisitForTemporaryDtors(E->getRHS(), false, RHSContext);
4627  InsertTempDtorDecisionBlock(RHSContext);
4628 
4629  return Block;
4630  }
4631 
4632  if (E->isAssignmentOp()) {
4633  // For assignment operator (=) LHS expression is visited
4634  // before RHS expression. For destructors visit them in reverse order.
4635  CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
4636  CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
4637  return LHSBlock ? LHSBlock : RHSBlock;
4638  }
4639 
4640  // For any other binary operator RHS expression is visited before
4641  // LHS expression (order of children). For destructors visit them in reverse
4642  // order.
4643  CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
4644  CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
4645  return RHSBlock ? RHSBlock : LHSBlock;
4646 }
4647 
4648 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors(
4649  CXXBindTemporaryExpr *E, bool BindToTemporary, TempDtorContext &Context) {
4650  // First add destructors for temporaries in subexpression.
4651  CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr(), false, Context);
4652  if (!BindToTemporary) {
4653  // If lifetime of temporary is not prolonged (by assigning to constant
4654  // reference) add destructor for it.
4655 
4656  const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor();
4657 
4658  if (Dtor->getParent()->isAnyDestructorNoReturn()) {
4659  // If the destructor is marked as a no-return destructor, we need to
4660  // create a new block for the destructor which does not have as a
4661  // successor anything built thus far. Control won't flow out of this
4662  // block.
4663  if (B) Succ = B;
4664  Block = createNoReturnBlock();
4665  } else if (Context.needsTempDtorBranch()) {
4666  // If we need to introduce a branch, we add a new block that we will hook
4667  // up to a decision block later.
4668  if (B) Succ = B;
4669  Block = createBlock();
4670  } else {
4671  autoCreateBlock();
4672  }
4673  if (Context.needsTempDtorBranch()) {
4674  Context.setDecisionPoint(Succ, E);
4675  }
4676  appendTemporaryDtor(Block, E);
4677 
4678  B = Block;
4679  }
4680  return B;
4681 }
4682 
4683 void CFGBuilder::InsertTempDtorDecisionBlock(const TempDtorContext &Context,
4684  CFGBlock *FalseSucc) {
4685  if (!Context.TerminatorExpr) {
4686  // If no temporary was found, we do not need to insert a decision point.
4687  return;
4688  }
4689  assert(Context.TerminatorExpr);
4690  CFGBlock *Decision = createBlock(false);
4691  Decision->setTerminator(CFGTerminator(Context.TerminatorExpr,
4693  addSuccessor(Decision, Block, !Context.KnownExecuted.isFalse());
4694  addSuccessor(Decision, FalseSucc ? FalseSucc : Context.Succ,
4695  !Context.KnownExecuted.isTrue());
4696  Block = Decision;
4697 }
4698 
4699 CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors(
4700  AbstractConditionalOperator *E, bool BindToTemporary,
4701  TempDtorContext &Context) {
4702  VisitForTemporaryDtors(E->getCond(), false, Context);
4703  CFGBlock *ConditionBlock = Block;
4704  CFGBlock *ConditionSucc = Succ;
4705  TryResult ConditionVal = tryEvaluateBool(E->getCond());
4706  TryResult NegatedVal = ConditionVal;
4707  if (NegatedVal.isKnown()) NegatedVal.negate();
4708 
4709  TempDtorContext TrueContext(
4710  bothKnownTrue(Context.KnownExecuted, ConditionVal));
4711  VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary, TrueContext);
4712  CFGBlock *TrueBlock = Block;
4713 
4714  Block = ConditionBlock;
4715  Succ = ConditionSucc;
4716  TempDtorContext FalseContext(
4717  bothKnownTrue(Context.KnownExecuted, NegatedVal));
4718  VisitForTemporaryDtors(E->getFalseExpr(), BindToTemporary, FalseContext);
4719 
4720  if (TrueContext.TerminatorExpr && FalseContext.TerminatorExpr) {
4721  InsertTempDtorDecisionBlock(FalseContext, TrueBlock);
4722  } else if (TrueContext.TerminatorExpr) {
4723  Block = TrueBlock;
4724  InsertTempDtorDecisionBlock(TrueContext);
4725  } else {
4726  InsertTempDtorDecisionBlock(FalseContext);
4727  }
4728  return Block;
4729 }
4730 
4731 /// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has
4732 /// no successors or predecessors. If this is the first block created in the
4733 /// CFG, it is automatically set to be the Entry and Exit of the CFG.
4735  bool first_block = begin() == end();
4736 
4737  // Create the block.
4738  CFGBlock *Mem = getAllocator().Allocate<CFGBlock>();
4739  new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this);
4740  Blocks.push_back(Mem, BlkBVC);
4741 
4742  // If this is the first block, set it as the Entry and Exit.
4743  if (first_block)
4744  Entry = Exit = &back();
4745 
4746  // Return the block.
4747  return &back();
4748 }
4749 
4750 /// buildCFG - Constructs a CFG from an AST.
4751 std::unique_ptr<CFG> CFG::buildCFG(const Decl *D, Stmt *Statement,
4752  ASTContext *C, const BuildOptions &BO) {
4753  CFGBuilder Builder(C, BO);
4754  return Builder.buildCFG(D, Statement);
4755 }
4756 
4757 bool CFG::isLinear() const {
4758  // Quick path: if we only have the ENTRY block, the EXIT block, and some code
4759  // in between, then we have no room for control flow.
4760  if (size() <= 3)
4761  return true;
4762 
4763  // Traverse the CFG until we find a branch.
4764  // TODO: While this should still be very fast,
4765  // maybe we should cache the answer.
4766  llvm::SmallPtrSet<const CFGBlock *, 4> Visited;
4767  const CFGBlock *B = Entry;
4768  while (B != Exit) {
4769  auto IteratorAndFlag = Visited.insert(B);
4770  if (!IteratorAndFlag.second) {
4771  // We looped back to a block that we've already visited. Not linear.
4772  return false;
4773  }
4774 
4775  // Iterate over reachable successors.
4776  const CFGBlock *FirstReachableB = nullptr;
4777  for (const CFGBlock::AdjacentBlock &AB : B->succs()) {
4778  if (!AB.isReachable())
4779  continue;
4780 
4781  if (FirstReachableB == nullptr) {
4782  FirstReachableB = &*AB;
4783  } else {
4784  // We've encountered a branch. It's not a linear CFG.
4785  return false;
4786  }
4787  }
4788 
4789  if (!FirstReachableB) {
4790  // We reached a dead end. EXIT is unreachable. This is linear enough.
4791  return true;
4792  }
4793 
4794  // There's only one way to move forward. Proceed.
4795  B = FirstReachableB;
4796  }
4797 
4798  // We reached EXIT and found no branches.
4799  return true;
4800 }
4801 
4802 const CXXDestructorDecl *
4804  switch (getKind()) {
4807  case CFGElement::LoopExit:
4809  case CFGElement::Statement:
4813  case CFGElement::ScopeEnd:
4814  llvm_unreachable("getDestructorDecl should only be used with "
4815  "ImplicitDtors");
4817  const VarDecl *var = castAs<CFGAutomaticObjDtor>().getVarDecl();
4818  QualType ty = var->getType();
4819 
4820  // FIXME: See CFGBuilder::addLocalScopeForVarDecl.
4821  //
4822  // Lifetime-extending constructs are handled here. This works for a single
4823  // temporary in an initializer expression.
4824  if (ty->isReferenceType()) {
4825  if (const Expr *Init = var->getInit()) {
4826  ty = getReferenceInitTemporaryType(Init);
4827  }
4828  }
4829 
4830  while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) {
4831  ty = arrayType->getElementType();
4832  }
4833  const RecordType *recordType = ty->getAs<RecordType>();
4834  const CXXRecordDecl *classDecl =
4835  cast<CXXRecordDecl>(recordType->getDecl());
4836  return classDecl->getDestructor();
4837  }
4838  case CFGElement::DeleteDtor: {
4839  const CXXDeleteExpr *DE = castAs<CFGDeleteDtor>().getDeleteExpr();
4840  QualType DTy = DE->getDestroyedType();
4841  DTy = DTy.getNonReferenceType();
4842  const CXXRecordDecl *classDecl =
4843  astContext.getBaseElementType(DTy)->getAsCXXRecordDecl();
4844  return classDecl->getDestructor();
4845  }
4847  const CXXBindTemporaryExpr *bindExpr =
4848  castAs<CFGTemporaryDtor>().getBindTemporaryExpr();
4849  const CXXTemporary *temp = bindExpr->getTemporary();
4850  return temp->getDestructor();
4851  }
4852  case CFGElement::BaseDtor:
4854  // Not yet supported.
4855  return nullptr;
4856  }
4857  llvm_unreachable("getKind() returned bogus value");
4858 }
4859 
4860 bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const {
4861  if (const CXXDestructorDecl *DD = getDestructorDecl(astContext))
4862  return DD->isNoReturn();
4863  return false;
4864 }
4865 
4866 //===----------------------------------------------------------------------===//
4867 // CFGBlock operations.
4868 //===----------------------------------------------------------------------===//
4869 
4871  : ReachableBlock(IsReachable ? B : nullptr),
4872  UnreachableBlock(!IsReachable ? B : nullptr,
4873  B && IsReachable ? AB_Normal : AB_Unreachable) {}
4874 
4876  : ReachableBlock(B),
4877  UnreachableBlock(B == AlternateBlock ? nullptr : AlternateBlock,
4878  B == AlternateBlock ? AB_Alternate : AB_Normal) {}
4879 
4881  BumpVectorContext &C) {
4882  if (CFGBlock *B = Succ.getReachableBlock())
4883  B->Preds.push_back(AdjacentBlock(this, Succ.isReachable()), C);
4884 
4885  if (CFGBlock *UnreachableB = Succ.getPossiblyUnreachableBlock())
4886  UnreachableB->Preds.push_back(AdjacentBlock(this, false), C);
4887 
4888  Succs.push_back(Succ, C);
4889 }
4890 
4892  const CFGBlock *From, const CFGBlock *To) {
4893  if (F.IgnoreNullPredecessors && !From)
4894  return true;
4895 
4896  if (To && From && F.IgnoreDefaultsWithCoveredEnums) {
4897  // If the 'To' has no label or is labeled but the label isn't a
4898  // CaseStmt then filter this edge.
4899  if (const SwitchStmt *S =
4900  dyn_cast_or_null<SwitchStmt>(From->getTerminatorStmt())) {
4901  if (S->isAllEnumCasesCovered()) {
4902  const Stmt *L = To->getLabel();
4903  if (!L || !isa<CaseStmt>(L))
4904  return true;
4905  }
4906  }
4907  }
4908 
4909  return false;
4910 }
4911 
4912 //===----------------------------------------------------------------------===//
4913 // CFG pretty printing
4914 //===----------------------------------------------------------------------===//
4915 
4916 namespace {
4917 
4918 class StmtPrinterHelper : public PrinterHelper {
4919  using StmtMapTy = llvm::DenseMap<const Stmt *, std::pair<unsigned, unsigned>>;
4920  using DeclMapTy = llvm::DenseMap<const Decl *, std::pair<unsigned, unsigned>>;
4921 
4922  StmtMapTy StmtMap;
4923  DeclMapTy DeclMap;
4924  signed currentBlock = 0;
4925  unsigned currStmt = 0;
4926  const LangOptions &LangOpts;
4927 
4928 public:
4929  StmtPrinterHelper(const CFG* cfg, const LangOptions &LO)
4930  : LangOpts(LO) {
4931  for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) {
4932  unsigned j = 1;
4933  for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ;
4934  BI != BEnd; ++BI, ++j ) {
4935  if (Optional<CFGStmt> SE = BI->getAs<CFGStmt>()) {
4936  const Stmt *stmt= SE->getStmt();
4937  std::pair<unsigned, unsigned> P((*I)->getBlockID(), j);
4938  StmtMap[stmt] = P;
4939 
4940  switch (stmt->getStmtClass()) {
4941  case Stmt::DeclStmtClass:
4942  DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P;
4943  break;
4944  case Stmt::IfStmtClass: {
4945  const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable();
4946  if (var)
4947  DeclMap[var] = P;
4948  break;
4949  }
4950  case Stmt::ForStmtClass: {
4951  const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable();
4952  if (var)
4953  DeclMap[var] = P;
4954  break;
4955  }
4956  case Stmt::WhileStmtClass: {
4957  const VarDecl *var =
4958  cast<WhileStmt>(stmt)->getConditionVariable();
4959  if (var)
4960  DeclMap[var] = P;
4961  break;
4962  }
4963  case Stmt::SwitchStmtClass: {
4964  const VarDecl *var =
4965  cast<SwitchStmt>(stmt)->getConditionVariable();
4966  if (var)
4967  DeclMap[var] = P;
4968  break;
4969  }
4970  case Stmt::CXXCatchStmtClass: {
4971  const VarDecl *var =
4972  cast<CXXCatchStmt>(stmt)->getExceptionDecl();
4973  if (var)
4974  DeclMap[var] = P;
4975  break;
4976  }
4977  default:
4978  break;
4979  }
4980  }
4981  }
4982  }
4983  }
4984 
4985  ~StmtPrinterHelper() override = default;
4986 
4987  const LangOptions &getLangOpts() const { return LangOpts; }
4988  void setBlockID(signed i) { currentBlock = i; }
4989  void setStmtID(unsigned i) { currStmt = i; }
4990 
4991  bool handledStmt(Stmt *S, raw_ostream &OS) override {
4992  StmtMapTy::iterator I = StmtMap.find(S);
4993 
4994  if (I == StmtMap.end())
4995  return false;
4996 
4997  if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
4998  && I->second.second == currStmt) {
4999  return false;
5000  }
5001 
5002  OS << "[B" << I->second.first << "." << I->second.second << "]";
5003  return true;
5004  }
5005 
5006  bool handleDecl(const Decl *D, raw_ostream &OS) {
5007  DeclMapTy::iterator I = DeclMap.find(D);
5008 
5009  if (I == DeclMap.end())
5010  return false;
5011 
5012  if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
5013  && I->second.second == currStmt) {
5014  return false;
5015  }
5016 
5017  OS << "[B" << I->second.first << "." << I->second.second << "]";
5018  return true;
5019  }
5020 };
5021 
5022 class CFGBlockTerminatorPrint
5023  : public StmtVisitor<CFGBlockTerminatorPrint,void> {
5024  raw_ostream &OS;
5025  StmtPrinterHelper* Helper;
5026  PrintingPolicy Policy;
5027 
5028 public:
5029  CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper,
5030  const PrintingPolicy &Policy)
5031  : OS(os), Helper(helper), Policy(Policy) {
5032  this->Policy.IncludeNewlines = false;
5033  }
5034 
5035  void VisitIfStmt(IfStmt *I) {
5036  OS << "if ";
5037  if (Stmt *C = I->getCond())
5038  C->printPretty(OS, Helper, Policy);
5039  }
5040 
5041  // Default case.
5042  void VisitStmt(Stmt *Terminator) {
5043  Terminator->printPretty(OS, Helper, Policy);
5044  }
5045 
5046  void VisitDeclStmt(DeclStmt *DS) {
5047  VarDecl *VD = cast<VarDecl>(DS->getSingleDecl());
5048  OS << "static init " << VD->getName();
5049  }
5050 
5051  void VisitForStmt(ForStmt *F) {
5052  OS << "for (" ;
5053  if (F->getInit())
5054  OS << "...";
5055  OS << "; ";
5056  if (Stmt *C = F->getCond())
5057  C->printPretty(OS, Helper, Policy);
5058  OS << "; ";
5059  if (F->getInc())
5060  OS << "...";
5061  OS << ")";
5062  }
5063 
5064  void VisitWhileStmt(WhileStmt *W) {
5065  OS << "while " ;
5066  if (Stmt *C = W->getCond())
5067  C->printPretty(OS, Helper, Policy);
5068  }
5069 
5070  void VisitDoStmt(DoStmt *D) {
5071  OS << "do ... while ";
5072  if (Stmt *C = D->getCond())
5073  C->printPretty(OS, Helper, Policy);
5074  }
5075 
5076  void VisitSwitchStmt(SwitchStmt *Terminator) {
5077  OS << "switch ";
5078  Terminator->getCond()->printPretty(OS, Helper, Policy);
5079  }
5080 
5081  void VisitCXXTryStmt(CXXTryStmt *CS) {
5082  OS << "try ...";
5083  }
5084 
5085  void VisitSEHTryStmt(SEHTryStmt *CS) {
5086  OS << "__try ...";
5087  }
5088 
5089  void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) {
5090  if (Stmt *Cond = C->getCond())
5091  Cond->printPretty(OS, Helper, Policy);
5092  OS << " ? ... : ...";
5093  }
5094 
5095  void VisitChooseExpr(ChooseExpr *C) {
5096  OS << "__builtin_choose_expr( ";
5097  if (Stmt *Cond = C->getCond())
5098  Cond->printPretty(OS, Helper, Policy);
5099  OS << " )";
5100  }
5101 
5102  void VisitIndirectGotoStmt(IndirectGotoStmt *I) {
5103  OS << "goto *";
5104  if (Stmt *T = I->getTarget())
5105  T->printPretty(OS, Helper, Policy);
5106  }
5107 
5108  void VisitBinaryOperator(BinaryOperator* B) {
5109  if (!B->isLogicalOp()) {
5110  VisitExpr(B);
5111  return;
5112  }
5113 
5114  if (B->getLHS())
5115  B->getLHS()->printPretty(OS, Helper, Policy);
5116 
5117  switch (B->getOpcode()) {
5118  case BO_LOr:
5119  OS << " || ...";
5120  return;
5121  case BO_LAnd:
5122  OS << " && ...";
5123  return;
5124  default:
5125  llvm_unreachable("Invalid logical operator.");
5126  }
5127  }
5128 
5129  void VisitExpr(Expr *E) {
5130  E->printPretty(OS, Helper, Policy);
5131  }
5132 
5133 public:
5134  void print(CFGTerminator T) {
5135  switch (T.getKind()) {
5137  Visit(T.getStmt());
5138  break;
5140  OS << "(Temp Dtor) ";
5141  Visit(T.getStmt());
5142  break;
5144  OS << "(See if most derived ctor has already initialized vbases)";
5145  break;
5146  }
5147  }
5148 };
5149 
5150 } // namespace
5151 
5152 static void print_initializer(raw_ostream &OS, StmtPrinterHelper &Helper,
5153  const CXXCtorInitializer *I) {
5154  if (I->isBaseInitializer())
5155  OS << I->getBaseClass()->getAsCXXRecordDecl()->getName();
5156  else if (I->isDelegatingInitializer())
5158  else
5159  OS << I->getAnyMember()->getName();
5160  OS << "(";
5161  if (Expr *IE = I->getInit())
5162  IE->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
5163  OS << ")";
5164 
5165  if (I->isBaseInitializer())
5166  OS << " (Base initializer)";
5167  else if (I->isDelegatingInitializer())
5168  OS << " (Delegating initializer)";
5169  else
5170  OS << " (Member initializer)";
5171 }
5172 
5173 static void print_construction_context(raw_ostream &OS,
5174  StmtPrinterHelper &Helper,
5175  const ConstructionContext *CC) {
5177  switch (CC->getKind()) {
5179  OS << ", ";
5180  const auto *SICC = cast<SimpleConstructorInitializerConstructionContext>(CC);
5181  print_initializer(OS, Helper, SICC->getCXXCtorInitializer());
5182  return;
5183  }
5185  OS << ", ";
5186  const auto *CICC =
5187  cast<CXX17ElidedCopyConstructorInitializerConstructionContext>(CC);
5188  print_initializer(OS, Helper, CICC->getCXXCtorInitializer());
5189  Stmts.push_back(CICC->getCXXBindTemporaryExpr());
5190  break;
5191  }
5193  const auto *SDSCC = cast<SimpleVariableConstructionContext>(CC);
5194  Stmts.push_back(SDSCC->getDeclStmt());
5195  break;
5196  }
5198  const auto *CDSCC = cast<CXX17ElidedCopyVariableConstructionContext>(CC);
5199  Stmts.push_back(CDSCC->getDeclStmt());
5200  Stmts.push_back(CDSCC->getCXXBindTemporaryExpr());
5201  break;
5202  }
5204  const auto *NECC = cast<NewAllocatedObjectConstructionContext>(CC);
5205  Stmts.push_back(NECC->getCXXNewExpr());
5206  break;
5207  }
5209  const auto *RSCC = cast<SimpleReturnedValueConstructionContext>(CC);
5210  Stmts.push_back(RSCC->getReturnStmt());
5211  break;
5212  }
5214  const auto *RSCC =
5215  cast<CXX17ElidedCopyReturnedValueConstructionContext>(CC);
5216  Stmts.push_back(RSCC->getReturnStmt());
5217  Stmts.push_back(RSCC->getCXXBindTemporaryExpr());
5218  break;
5219  }
5221  const auto *TOCC = cast<SimpleTemporaryObjectConstructionContext>(CC);
5222  Stmts.push_back(TOCC->getCXXBindTemporaryExpr());
5223  Stmts.push_back(TOCC->getMaterializedTemporaryExpr());
5224  break;
5225  }
5227  const auto *TOCC = cast<ElidedTemporaryObjectConstructionContext>(CC);
5228  Stmts.push_back(TOCC->getCXXBindTemporaryExpr());
5229  Stmts.push_back(TOCC->getMaterializedTemporaryExpr());
5230  Stmts.push_back(TOCC->getConstructorAfterElision());
5231  break;
5232  }
5234  const auto *ACC = cast<ArgumentConstructionContext>(CC);
5235  if (const Stmt *BTE = ACC->getCXXBindTemporaryExpr()) {
5236  OS << ", ";
5237  Helper.handledStmt(const_cast<Stmt *>(BTE), OS);
5238  }
5239  OS << ", ";
5240  Helper.handledStmt(const_cast<Expr *>(ACC->getCallLikeExpr()), OS);
5241  OS << "+" << ACC->getIndex();
5242  return;
5243  }
5244  }
5245  for (auto I: Stmts)
5246  if (I) {
5247  OS << ", ";
5248  Helper.handledStmt(const_cast<Stmt *>(I), OS);
5249  }
5250 }
5251 
5252 static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
5253  const CFGElement &E) {
5254  if (Optional<CFGStmt> CS = E.getAs<CFGStmt>()) {
5255  const Stmt *S = CS->getStmt();
5256  assert(S != nullptr && "Expecting non-null Stmt");
5257 
5258  // special printing for statement-expressions.
5259  if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) {
5260  const CompoundStmt *Sub = SE->getSubStmt();
5261 
5262  auto Children = Sub->children();
5263  if (Children.begin() != Children.end()) {
5264  OS << "({ ... ; ";
5265  Helper.handledStmt(*SE->getSubStmt()->body_rbegin(),OS);
5266  OS << " })\n";
5267  return;
5268  }
5269  }
5270  // special printing for comma expressions.
5271  if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) {
5272  if (B->getOpcode() == BO_Comma) {
5273  OS << "... , ";
5274  Helper.handledStmt(B->getRHS(),OS);
5275  OS << '\n';
5276  return;
5277  }
5278  }
5279  S->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
5280 
5281  if (auto VTC = E.getAs<CFGCXXRecordTypedCall>()) {
5282  if (isa<CXXOperatorCallExpr>(S))
5283  OS << " (OperatorCall)";
5284  OS << " (CXXRecordTypedCall";
5285  print_construction_context(OS, Helper, VTC->getConstructionContext());
5286  OS << ")";
5287  } else if (isa<CXXOperatorCallExpr>(S)) {
5288  OS << " (OperatorCall)";
5289  } else if (isa<CXXBindTemporaryExpr>(S)) {
5290  OS << " (BindTemporary)";
5291  } else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) {
5292  OS << " (CXXConstructExpr";
5294  print_construction_context(OS, Helper, CE->getConstructionContext());
5295  }
5296  OS << ", " << CCE->getType().getAsString() << ")";
5297  } else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) {
5298  OS << " (" << CE->getStmtClassName() << ", "
5299  << CE->getCastKindName()
5300  << ", " << CE->getType().getAsString()
5301  << ")";
5302  }
5303 
5304  // Expressions need a newline.
5305  if (isa<Expr>(S))
5306  OS << '\n';
5307  } else if (Optional<CFGInitializer> IE = E.getAs<CFGInitializer>()) {
5308  print_initializer(OS, Helper, IE->getInitializer());
5309  OS << '\n';
5310  } else if (Optional<CFGAutomaticObjDtor> DE =
5311  E.getAs<CFGAutomaticObjDtor>()) {
5312  const VarDecl *VD = DE->getVarDecl();
5313  Helper.handleDecl(VD, OS);
5314 
5315  ASTContext &ACtx = VD->getASTContext();
5316  QualType T = VD->getType();
5317  if (T->isReferenceType())
5318  T = getReferenceInitTemporaryType(VD->getInit(), nullptr);
5319  if (const ArrayType *AT = ACtx.getAsArrayType(T))
5320  T = ACtx.getBaseElementType(AT);
5321 
5322  OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()";
5323  OS << " (Implicit destructor)\n";
5324  } else if (Optional<CFGLifetimeEnds> DE = E.getAs<CFGLifetimeEnds>()) {
5325  const VarDecl *VD = DE->getVarDecl();
5326  Helper.handleDecl(VD, OS);
5327 
5328  OS << " (Lifetime ends)\n";
5329  } else if (Optional<CFGLoopExit> LE = E.getAs<CFGLoopExit>()) {
5330  const Stmt *LoopStmt = LE->getLoopStmt();
5331  OS << LoopStmt->getStmtClassName() << " (LoopExit)\n";
5332  } else if (Optional<CFGScopeBegin> SB = E.getAs<CFGScopeBegin>()) {
5333  OS << "CFGScopeBegin(";
5334  if (const VarDecl *VD = SB->getVarDecl())
5335  OS << VD->getQualifiedNameAsString();
5336  OS << ")\n";
5337  } else if (Optional<CFGScopeEnd> SE = E.getAs<CFGScopeEnd>()) {
5338  OS << "CFGScopeEnd(";
5339  if (const VarDecl *VD = SE->getVarDecl())
5340  OS << VD->getQualifiedNameAsString();
5341  OS << ")\n";
5342  } else if (Optional<CFGNewAllocator> NE = E.getAs<CFGNewAllocator>()) {
5343  OS << "CFGNewAllocator(";
5344  if (const CXXNewExpr *AllocExpr = NE->getAllocatorExpr())
5345  AllocExpr->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
5346  OS << ")\n";
5347  } else if (Optional<CFGDeleteDtor> DE = E.getAs<CFGDeleteDtor>()) {
5348  const CXXRecordDecl *RD = DE->getCXXRecordDecl();
5349  if (!RD)
5350  return;
5351  CXXDeleteExpr *DelExpr =
5352  const_cast<CXXDeleteExpr*>(DE->getDeleteExpr());
5353  Helper.handledStmt(cast<Stmt>(DelExpr->getArgument()), OS);
5354  OS << "->~" << RD->getName().str() << "()";
5355  OS << " (Implicit destructor)\n";
5356  } else if (Optional<CFGBaseDtor> BE = E.getAs<CFGBaseDtor>()) {
5357  const CXXBaseSpecifier *BS = BE->getBaseSpecifier();
5358  OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()";
5359  OS << " (Base object destructor)\n";
5360  } else if (Optional<CFGMemberDtor> ME = E.getAs<CFGMemberDtor>()) {
5361  const FieldDecl *FD = ME->getFieldDecl();
5362  const Type *T = FD->getType()->getBaseElementTypeUnsafe();
5363  OS << "this->" << FD->getName();
5364  OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()";
5365  OS << " (Member object destructor)\n";
5366  } else if (Optional<CFGTemporaryDtor> TE = E.getAs<CFGTemporaryDtor>()) {
5367  const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr();
5368  OS << "~";
5369  BT->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
5370  OS << "() (Temporary object destructor)\n";
5371  }
5372 }
5373 
5374 static void print_block(raw_ostream &OS, const CFG* cfg,
5375  const CFGBlock &B,
5376  StmtPrinterHelper &Helper, bool print_edges,
5377  bool ShowColors) {
5378  Helper.setBlockID(B.getBlockID());
5379 
5380  // Print the header.
5381  if (ShowColors)
5382  OS.changeColor(raw_ostream::YELLOW, true);
5383 
5384  OS << "\n [B" << B.getBlockID();
5385 
5386  if (&B == &cfg->getEntry())
5387  OS << " (ENTRY)]\n";
5388  else if (&B == &cfg->getExit())
5389  OS << " (EXIT)]\n";
5390  else if (&B == cfg->getIndirectGotoBlock())
5391  OS << " (INDIRECT GOTO DISPATCH)]\n";
5392  else if (B.hasNoReturnElement())
5393  OS << " (NORETURN)]\n";
5394  else
5395  OS << "]\n";
5396 
5397  if (ShowColors)
5398  OS.resetColor();
5399 
5400  // Print the label of this block.
5401  if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) {
5402  if (print_edges)
5403  OS << " ";
5404 
5405  if (LabelStmt *L = dyn_cast<LabelStmt>(Label))
5406  OS << L->getName();
5407  else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) {
5408  OS << "case ";
5409  if (C->getLHS())
5410  C->getLHS()->printPretty(OS, &Helper,
5411  PrintingPolicy(Helper.getLangOpts()));
5412  if (C->getRHS()) {
5413  OS << " ... ";
5414  C->getRHS()->printPretty(OS, &Helper,
5415  PrintingPolicy(Helper.getLangOpts()));
5416  }
5417  } else if (isa<DefaultStmt>(Label))
5418  OS << "default";
5419  else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) {
5420  OS << "catch (";
5421  if (CS->getExceptionDecl())
5422  CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper.getLangOpts()),
5423  0);
5424  else
5425  OS << "...";
5426  OS << ")";
5427  } else if (SEHExceptStmt *ES = dyn_cast<SEHExceptStmt>(Label)) {
5428  OS << "__except (";
5429  ES->getFilterExpr()->printPretty(OS, &Helper,
5430  PrintingPolicy(Helper.getLangOpts()), 0);
5431  OS << ")";
5432  } else
5433  llvm_unreachable("Invalid label statement in CFGBlock.");
5434 
5435  OS << ":\n";
5436  }
5437 
5438  // Iterate through the statements in the block and print them.
5439  unsigned j = 1;
5440 
5441  for (CFGBlock::const_iterator I = B.begin(), E = B.end() ;
5442  I != E ; ++I, ++j ) {
5443  // Print the statement # in the basic block and the statement itself.
5444  if (print_edges)
5445  OS << " ";
5446 
5447  OS << llvm::format("%3d", j) << ": ";
5448 
5449  Helper.setStmtID(j);
5450 
5451  print_elem(OS, Helper, *I);
5452  }
5453 
5454  // Print the terminator of this block.
5455  if (B.getTerminator().isValid()) {
5456  if (ShowColors)
5457  OS.changeColor(raw_ostream::GREEN);
5458 
5459  OS << " T: ";
5460 
5461  Helper.setBlockID(-1);
5462 
5463  PrintingPolicy PP(Helper.getLangOpts());
5464  CFGBlockTerminatorPrint TPrinter(OS, &Helper, PP);
5465  TPrinter.print(B.getTerminator());
5466  OS << '\n';
5467 
5468  if (ShowColors)
5469  OS.resetColor();
5470  }
5471 
5472  if (print_edges) {
5473  // Print the predecessors of this block.
5474  if (!B.pred_empty()) {
5475  const raw_ostream::Colors Color = raw_ostream::BLUE;
5476  if (ShowColors)
5477  OS.changeColor(Color);
5478  OS << " Preds " ;
5479  if (ShowColors)
5480  OS.resetColor();
5481  OS << '(' << B.pred_size() << "):";
5482  unsigned i = 0;
5483 
5484  if (ShowColors)
5485  OS.changeColor(Color);
5486 
5487  for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end();
5488  I != E; ++I, ++i) {
5489  if (i % 10 == 8)
5490  OS << "\n ";
5491 
5492  CFGBlock *B = *I;
5493  bool Reachable = true;
5494  if (!B) {
5495  Reachable = false;
5496  B = I->getPossiblyUnreachableBlock();
5497  }
5498 
5499  OS << " B" << B->getBlockID();
5500  if (!Reachable)
5501  OS << "(Unreachable)";
5502  }
5503 
5504  if (ShowColors)
5505  OS.resetColor();
5506 
5507  OS << '\n';
5508  }
5509 
5510  // Print the successors of this block.
5511  if (!B.succ_empty()) {
5512  const raw_ostream::Colors Color = raw_ostream::MAGENTA;
5513  if (ShowColors)
5514  OS.changeColor(Color);
5515  OS << " Succs ";
5516  if (ShowColors)
5517  OS.resetColor();
5518  OS << '(' << B.succ_size() << "):";
5519  unsigned i = 0;
5520 
5521  if (ShowColors)
5522  OS.changeColor(Color);
5523 
5524  for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end();
5525  I != E; ++I, ++i) {
5526  if (i % 10 == 8)
5527  OS << "\n ";
5528 
5529  CFGBlock *B = *I;
5530 
5531  bool Reachable = true;
5532  if (!B) {
5533  Reachable = false;
5534  B = I->getPossiblyUnreachableBlock();
5535  }
5536 
5537  if (B) {
5538  OS << " B" << B->getBlockID();
5539  if (!Reachable)
5540  OS << "(Unreachable)";
5541  }
5542  else {
5543  OS << " NULL";
5544  }
5545  }
5546 
5547  if (ShowColors)
5548  OS.resetColor();
5549  OS << '\n';
5550  }
5551  }
5552 }
5553 
5554 /// dump - A simple pretty printer of a CFG that outputs to stderr.
5555 void CFG::dump(const LangOptions &LO, bool ShowColors) const {
5556  print(llvm::errs(), LO, ShowColors);
5557 }
5558 
5559 /// print - A simple pretty printer of a CFG that outputs to an ostream.
5560 void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const {
5561  StmtPrinterHelper Helper(this, LO);
5562 
5563  // Print the entry block.
5564  print_block(OS, this, getEntry(), Helper, true, ShowColors);
5565 
5566  // Iterate through the CFGBlocks and print them one by one.
5567  for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) {
5568  // Skip the entry block, because we already printed it.
5569  if (&(**I) == &getEntry() || &(**I) == &getExit())
5570  continue;
5571 
5572  print_block(OS, this, **I, Helper, true, ShowColors);
5573  }
5574 
5575  // Print the exit block.
5576  print_block(OS, this, getExit(), Helper, true, ShowColors);
5577  OS << '\n';
5578  OS.flush();
5579 }
5580 
5581 /// dump - A simply pretty printer of a CFGBlock that outputs to stderr.
5582 void CFGBlock::dump(const CFG* cfg, const LangOptions &LO,
5583  bool ShowColors) const {
5584  print(llvm::errs(), cfg, LO, ShowColors);
5585 }
5586 
5587 LLVM_DUMP_METHOD void CFGBlock::dump() const {
5588  dump(getParent(), LangOptions(), false);
5589 }
5590 
5591 /// print - A simple pretty printer of a CFGBlock that outputs to an ostream.
5592 /// Generally this will only be called from CFG::print.
5593 void CFGBlock::print(raw_ostream &OS, const CFG* cfg,
5594  const LangOptions &LO, bool ShowColors) const {
5595  StmtPrinterHelper Helper(cfg, LO);
5596  print_block(OS, cfg, *this, Helper, true, ShowColors);
5597  OS << '\n';
5598 }
5599 
5600 /// printTerminator - A simple pretty printer of the terminator of a CFGBlock.
5601 void CFGBlock::printTerminator(raw_ostream &OS,
5602  const LangOptions &LO) const {
5603  CFGBlockTerminatorPrint TPrinter(OS, nullptr, PrintingPolicy(LO));
5604  TPrinter.print(getTerminator());
5605 }
5606 
5607 /// printTerminatorJson - Pretty-prints the terminator in JSON format.
5608 void CFGBlock::printTerminatorJson(raw_ostream &Out, const LangOptions &LO,
5609  bool AddQuotes) const {
5610  std::string Buf;
5611  llvm::raw_string_ostream TempOut(Buf);
5612 
5613  printTerminator(TempOut, LO);
5614 
5615  Out << JsonFormat(TempOut.str(), AddQuotes);
5616 }
5617 
5619  Stmt *Terminator = getTerminatorStmt();
5620  if (!Terminator)
5621  return nullptr;
5622 
5623  Expr *E = nullptr;
5624 
5625  switch (Terminator->getStmtClass()) {
5626  default:
5627  break;
5628 
5629  case Stmt::CXXForRangeStmtClass:
5630  E = cast<CXXForRangeStmt>(Terminator)->getCond();
5631  break;
5632 
5633  case Stmt::ForStmtClass:
5634  E = cast<ForStmt>(Terminator)->getCond();
5635  break;
5636 
5637  case Stmt::WhileStmtClass:
5638  E = cast<WhileStmt>(Terminator)->getCond();
5639  break;
5640 
5641  case Stmt::DoStmtClass:
5642  E = cast<DoStmt>(Terminator)->getCond();
5643  break;
5644 
5645  case Stmt::IfStmtClass:
5646  E = cast<IfStmt>(Terminator)->getCond();
5647  break;
5648 
5649  case Stmt::ChooseExprClass:
5650  E = cast<ChooseExpr>(Terminator)->getCond();
5651  break;
5652 
5653  case Stmt::IndirectGotoStmtClass:
5654  E = cast<IndirectGotoStmt>(Terminator)->getTarget();
5655  break;
5656 
5657  case Stmt::SwitchStmtClass:
5658  E = cast<SwitchStmt>(Terminator)->getCond();
5659  break;
5660 
5661  case Stmt::BinaryConditionalOperatorClass:
5662  E = cast<BinaryConditionalOperator>(Terminator)->getCond();
5663  break;
5664 
5665  case Stmt::ConditionalOperatorClass:
5666  E = cast<ConditionalOperator>(Terminator)->getCond();
5667  break;
5668 
5669  case Stmt::BinaryOperatorClass: // '&&' and '||'
5670  E = cast<BinaryOperator>(Terminator)->getLHS();
5671  break;
5672 
5673  case Stmt::ObjCForCollectionStmtClass:
5674  return Terminator;
5675  }
5676 
5677  if (!StripParens)
5678  return E;
5679 
5680  return E ? E->IgnoreParens() : nullptr;
5681 }
5682 
5683 //===----------------------------------------------------------------------===//
5684 // CFG Graphviz Visualization
5685 //===----------------------------------------------------------------------===//
5686 
5687 #ifndef NDEBUG
5688 static StmtPrinterHelper* GraphHelper;
5689 #endif
5690 
5691 void CFG::viewCFG(const LangOptions &LO) const {
5692 #ifndef NDEBUG
5693  StmtPrinterHelper H(this, LO);
5694  GraphHelper = &H;
5695  llvm::ViewGraph(this,"CFG");
5696  GraphHelper = nullptr;
5697 #endif
5698 }
5699 
5700 namespace llvm {
5701 
5702 template<>
5703 struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits {
5704  DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
5705 
5706  static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) {
5707 #ifndef NDEBUG
5708  std::string OutSStr;
5709  llvm::raw_string_ostream Out(OutSStr);
5710  print_block(Out,Graph, *Node, *GraphHelper, false, false);
5711  std::string& OutStr = Out.str();
5712 
5713  if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
5714 
5715  // Process string output to make it nicer...
5716  for (unsigned i = 0; i != OutStr.length(); ++i)
5717  if (OutStr[i] == '\n') { // Left justify
5718  OutStr[i] = '\\';
5719  OutStr.insert(OutStr.begin()+i+1, 'l');
5720  }
5721 
5722  return OutStr;
5723 #else
5724  return {};
5725 #endif
5726  }
5727 };
5728 
5729 } // namespace llvm
Expr * getInc()
Definition: Stmt.h:2402
unsigned getNumSemanticExprs() const
Definition: Expr.h:5727
const Expr * getSubExpr() const
Definition: Expr.h:933
bool isBaseInitializer() const
Determine whether this initializer is initializing a base class.
Definition: DeclCXX.h:2407
bool isNoReturn() const
Determines whether this function is known to be &#39;noreturn&#39;, through an attribute on its declaration o...
Definition: Decl.cpp:3013
Defines the clang::ASTContext interface.
const BlockDecl * getBlockDecl() const
Definition: Expr.h:5555
Represents C++ allocator call.
Definition: CFG.h:239
const CXXDestructorDecl * getDestructor() const
Definition: ExprCXX.h:1256
This represents a GCC inline-assembly statement extension.
Definition: Stmt.h:2837
Represents a function declaration or definition.
Definition: Decl.h:1748
Expr * getInit() const
Get the initializer.
Definition: DeclCXX.h:2536
CompoundStmt * getBlock() const
Definition: Stmt.h:3228
A class which contains all the information about a particular captured value.
Definition: Decl.h:3895
pred_iterator pred_end()
Definition: CFG.h:752
PointerType - C99 6.7.5.1 - Pointer Declarators.
Definition: Type.h:2554
QualType getPointeeType() const
Definition: Type.h:2567
A (possibly-)qualified type.
Definition: Type.h:643
bool isBlockPointerType() const
Definition: Type.h:6359
base_class_range bases()
Definition: DeclCXX.h:825
Expr * getCond() const
Definition: Expr.h:4143
static SourceLocation GetEndLoc(Decl *D)
Definition: CFG.cpp:66
AdjacentBlocks::const_iterator const_pred_iterator
Definition: CFG.h:738
iterator beginScopeEndInsert(iterator I, size_t Cnt, BumpVectorContext &C)
Definition: CFG.h:997
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:2234
DOTGraphTraits(bool isSimple=false)
Definition: CFG.cpp:5704
ElementList::iterator iterator
Definition: CFG.h:713
succ_iterator succ_begin()
Definition: CFG.h:769
CompoundStmt * getSubStmt()
Definition: Expr.h:3938
DominatorTree GraphTraits specialization so the DominatorTree can be iterable by generic graph iterat...
Definition: Dominators.h:29
bool isReachable() const
Definition: CFG.h:681
const DeclStmt * getConditionVariableDeclStmt() const
If this ForStmt has a condition variable, return the faux DeclStmt associated with the creation of th...
Definition: Stmt.h:2397
Stmt - This represents one statement.
Definition: Stmt.h:66
FunctionType - C99 6.7.5.3 - Function Declarators.
Definition: Type.h:3372
CXXCatchStmt * getHandler(unsigned i)
Definition: StmtCXX.h:107
CFGBlock & getEntry()
Definition: CFG.h:1118
IfStmt - This represents an if/then/else.
Definition: Stmt.h:1797
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:932
C Language Family Type Representation.
Expr * getBase() const
Definition: Expr.h:2884
void prependScopeBegin(const VarDecl *VD, const Stmt *S, BumpVectorContext &C)
Definition: CFG.h:927
unsigned getBlockID() const
Definition: CFG.h:876
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:3440
StringRef P
void appendNewAllocator(CXXNewExpr *NE, BumpVectorContext &C)
Definition: CFG.h:917
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:6300
void appendLifetimeEnds(VarDecl *VD, Stmt *S, BumpVectorContext &C)
Definition: CFG.h:956
The base class of the type hierarchy.
Definition: Type.h:1418
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:2829
iterator begin()
Definition: CFG.h:721
Represents a call to a C++ constructor.
Definition: ExprCXX.h:1326
DOTGraphTraits(bool isSimple=false)
unsigned IgnoreDefaultsWithCoveredEnums
Definition: CFG.h:797
Represents a prvalue temporary that is written into memory so that a reference can bind to it...
Definition: ExprCXX.h:4320
float __ovld __cnfn distance(float p0, float p1)
Returns the distance between p0 and p1.
A shortcut around virtual base initializers.
Definition: CFG.h:510
void prependScopeEnd(const VarDecl *VD, const Stmt *S, BumpVectorContext &C)
Definition: CFG.h:936
bool isCompleteDefinition() const
Return true if this decl has its body fully specified.
Definition: Decl.h:3200
unsigned succ_size() const
Definition: CFG.h:787
const CXXDestructorDecl * getDestructorDecl(ASTContext &astContext) const
Definition: CFG.cpp:4803
Stmt * getSubStmt()
Definition: Stmt.h:1630
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:6818
CFGBlock * getReachableBlock() const
Get the reachable block, if one exists.
Definition: CFG.h:658
const char * getName() const
Definition: Stmt.cpp:340
Stmt * getThen()
Definition: Stmt.h:1884
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:5252
A C++ throw-expression (C++ [except.throw]).
Definition: ExprCXX.h:1044
Represents an expression – generally a full-expression – that introduces cleanups to be run at the ...
Definition: ExprCXX.h:3207
static bool isAssignmentOp(Opcode Opc)
Definition: Expr.h:3531
Defines the clang::Expr interface and subclasses for C++ expressions.
long i
Definition: xmmintrin.h:1456
void printTerminatorJson(raw_ostream &Out, const LangOptions &LO, bool AddQuotes) const
printTerminatorJson - Pretty-prints the terminator in JSON format.
Definition: CFG.cpp:5608
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:1695
const AstTypeMatcher< RecordType > recordType
Matches record types (e.g.
static TryResult bothKnownTrue(TryResult R1, TryResult R2)
Definition: CFG.cpp:382
bool pred_empty() const
Definition: CFG.h:791
Stmt * getBody()
Definition: Stmt.h:2338
CFGBlock * getPossiblyUnreachableBlock() const
Get the potentially unreachable block.
Definition: CFG.h:663
void print(raw_ostream &Out, unsigned Indentation=0, bool PrintInstantiation=false) const
QualType getPointeeType() const
Definition: Type.h:2671
DeclStmt * getConditionVariableDeclStmt()
If this SwitchStmt has a condition variable, return the faux DeclStmt associated with the creation of...
Definition: Stmt.h:2119
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:855
static std::string getNodeLabel(const CFGBlock *Node, const CFG *Graph)
Definition: CFG.cpp:5706
field_range fields() const
Definition: Decl.h:3815
Represents a member of a struct/union/class.
Definition: Decl.h:2605
TypeSourceInfo * getTypeSourceInfo() const
Returns the declarator information for a base class or delegating initializer.
Definition: DeclCXX.h:2468
iterator insertAutomaticObjDtor(iterator I, VarDecl *VD, Stmt *S)
Definition: CFG.h:976
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:5601
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:952
bool isReferenceType() const
Definition: Type.h:6363
const CXXConstructExpr * getConstructExpr() const
Returns the CXXConstructExpr from this new-expression, or null.
Definition: ExprCXX.h:2188
succ_range succs()
Definition: CFG.h:779
bool isAsmGoto() const
Definition: Stmt.h:2982
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:2156
Expr * getSubExpr()
Definition: Expr.h:3173
void setTerminator(CFGTerminator Term)
Definition: CFG.h:853
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:1104
bool EvaluateAsBooleanCondition(bool &Result, const ASTContext &Ctx, bool InConstantContext=false) const
EvaluateAsBooleanCondition - Return true if this is a constant which we can fold and convert to a boo...
Represents Objective-C&#39;s @catch statement.
Definition: StmtObjC.h:77
AdjacentBlocks::const_iterator const_succ_iterator
Definition: CFG.h:745
bool isGLValue() const
Definition: Expr.h:261
IndirectGotoStmt - This represents an indirect goto.
Definition: Stmt.h:2479
Describes an C or C++ initializer list.
Definition: Expr.h:4371
BinaryOperatorKind
Optional< Expr * > getArraySize()
Definition: ExprCXX.h:2126
std::string JsonFormat(StringRef RawSR, bool AddQuotes)
Definition: JsonSupport.h:26
Kind getKind() const
Definition: CFG.h:531
ForStmt - This represents a &#39;for (init;cond;inc)&#39; stmt.
Definition: Stmt.h:2369
APValue Val
Val - This is the value the expression can be folded to.
Definition: Expr.h:582
LabelDecl * getDecl() const
Definition: Stmt.h:1712
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:1867
Expr * getInitializer()
The initializer of this new-expression.
Definition: ExprCXX.h:2176
Stmt * getBody()
Definition: Stmt.h:2403
CFGCallback * Observer
Definition: CFG.h:1040
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:1614
A builtin binary operation expression such as "x + y" or "x <= y".
Definition: Expr.h:3405
Stmt * getInit()
Definition: Stmt.h:2382
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:121
void print(raw_ostream &OS, const CFG *cfg, const LangOptions &LO, bool ShowColors) const
print - A simple pretty printer of a CFGBlock that outputs to an ostream.
Definition: CFG.cpp:5593
bool isLinear() const
Returns true if the CFG has no branches.
Definition: CFG.cpp:4757
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:6127
b
Definition: emmintrin.h:321
CaseStmt - Represent a case statement.
Definition: Stmt.h:1463
void appendLoopExit(const Stmt *LoopStmt, BumpVectorContext &C)
Definition: CFG.h:960
Expr * getCond()
Definition: Stmt.h:2401
bool isInt() const
Definition: APValue.h:317
CastExpr - Base class for type casts, including both implicit casts (ImplicitCastExpr) and explicit c...
Definition: Expr.h:3121
Represents binding an expression to a temporary.
Definition: ExprCXX.h:1277
CXXTemporary * getTemporary()
Definition: ExprCXX.h:1296
FieldDecl * getAnyMember() const
Definition: DeclCXX.h:2480
A C++ lambda expression, which produces a function object (of unspecified type) that can be invoked l...
Definition: ExprCXX.h:1722
bool hasTrivialDestructor() const
Determine whether this class has a trivial destructor (C++ [class.dtor]p3)
Definition: DeclCXX.h:1491
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:176
child_range children()
Definition: Stmt.h:1410
CXXDestructorDecl * getDestructor() const
Returns the destructor decl for this class.
Definition: DeclCXX.cpp:1736
VarDecl * getConditionVariable() const
Retrieve the variable declared in this "for" statement, if any.
Definition: Stmt.cpp:913
bool getNoReturn() const
Definition: Type.h:3529
Stmt * getBody()
Definition: Stmt.h:2074
Stmt * getInit()
Definition: Stmt.h:1940
arg_iterator placement_arg_end()
Definition: ExprCXX.h:2217
llvm::DenseMap< const Stmt *, const CFGBlock * > ForcedBlkExprs
Definition: CFG.h:1037
CFGBlockListTy::const_iterator const_iterator
Definition: CFG.h:1096
CFG * getParent() const
Definition: CFG.h:878
void appendConstructor(CXXConstructExpr *CE, const ConstructionContext *CC, BumpVectorContext &C)
Definition: CFG.h:901
CompoundStmt - This represents a group of statements like { stmt stmt }.
Definition: Stmt.h:1310
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:3704
bool isDelegatingInitializer() const
Determine whether this initializer is creating a delegating constructor.
Definition: DeclCXX.h:2435
UnaryExprOrTypeTraitExpr - expression with either a type or (unevaluated) expression operand...
Definition: Expr.h:2342
void appendBaseDtor(const CXXBaseSpecifier *BS, BumpVectorContext &C)
Definition: CFG.h:940
static bool shouldAddCase(bool &switchExclusivelyCovered, const Expr::EvalResult *switchCond, const CaseStmt *CS, ASTContext &Ctx)
Definition: CFG.cpp:4009
Represents a single basic block in a source-level CFG.
Definition: CFG.h:570
ConstantExpr - An expression that occurs in a constant context and optionally the result of evaluatin...
Definition: Expr.h:948
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:4860
This represents one expression.
Definition: Expr.h:108
Defines the clang::LangOptions interface.
Stmt * getTerminatorCondition(bool StripParens=true)
Definition: CFG.cpp:5618
static std::tuple< const DeclRefExpr *, BinaryOperatorKind, const Expr * > tryNormalizeBinaryOperator(const BinaryOperator *B)
Tries to interpret a binary operator into Decl Op Expr form, if Expr is an integer literal or an enum...
Definition: CFG.cpp:90
DeclStmt * getEndStmt()
Definition: StmtCXX.h:165
SourceLocation End
std::string Label
Represents a source-level, intra-procedural CFG that represents the control-flow of a Stmt...
Definition: CFG.h:1027
Represents a C++ functional cast expression that builds a temporary object.
Definition: ExprCXX.h:1654
BlockExpr - Adaptor class for mixing a BlockDecl with expressions.
Definition: Expr.h:5541
Represents a C++ destructor within a class.
Definition: DeclCXX.h:2830
bool succ_empty() const
Definition: CFG.h:788
VarDecl * getExceptionDecl() const
Definition: StmtCXX.h:49
Expr * getCallee()
Definition: Expr.h:2634
unsigned getNumInits() const
Definition: Expr.h:4401
Represents C++ constructor call.
Definition: CFG.h:150
QualType getArgumentType() const
Definition: Expr.h:2379
#define bool
Definition: stdbool.h:15
Stmt * getBody()
Definition: Stmt.h:2246
const CompoundStmt * getSynchBody() const
Definition: StmtObjC.h:297
ElementList::const_iterator const_iterator
Definition: CFG.h:714
Expr * getRHS()
Definition: Stmt.h:1564
Represents Objective-C&#39;s @synchronized statement.
Definition: StmtObjC.h:277
SourceLocation Begin
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:2652
const AstTypeMatcher< ArrayType > arrayType
Matches all kinds of arrays.
std::reverse_iterator< body_iterator > reverse_body_iterator
Definition: Stmt.h:1378
QualType getType() const
Definition: Expr.h:137
static void print_initializer(raw_ostream &OS, StmtPrinterHelper &Helper, const CXXCtorInitializer *I)
Definition: CFG.cpp:5152
LabelDecl * getLabel() const
Definition: Stmt.h:2453
StorageDuration getStorageDuration() const
Retrieve the storage duration for the materialized temporary.
Definition: ExprCXX.h:4364
An expression that sends a message to the given Objective-C object or class.
Definition: ExprObjC.h:950
SwitchCase * getSwitchCaseList()
Definition: Stmt.h:2131
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:2016
static bool CanThrow(Expr *E, ASTContext &Ctx)
Definition: CFG.cpp:2469
const Type * getBaseElementTypeUnsafe() const
Get the base element type of this type, potentially discarding type qualifiers.
Definition: Type.h:6758
Expr * getCond()
Definition: Stmt.h:1872
ValueDecl * getDecl()
Definition: Expr.h:1217
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:1300
bool isNull() const
Return true if this QualType doesn&#39;t point to a type yet.
Definition: Type.h:708
DoStmt - This represents a &#39;do/while&#39; stmt.
Definition: Stmt.h:2313
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:1262
RecordDecl * getDecl() const
Definition: Type.h:4433
Expr * getArgument()
Definition: ExprCXX.h:2302
void appendStmt(Stmt *statement, BumpVectorContext &C)
Definition: CFG.h:897
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...
OpaqueValueExpr - An expression referring to an opaque object of a fixed type and value class...
Definition: Expr.h:1045
Kind
PseudoObjectExpr - An expression which accesses a pseudo-object l-value.
Definition: Expr.h:5663
Construction context can be seen as a linked list of multiple layers.
Encodes a location in the source.
Stmt * getLabel()
Definition: CFG.h:871
unsigned getNumHandlers() const
Definition: StmtCXX.h:106
Expr * getSubExpr() const
Definition: Expr.h:2046
Represents a C++ temporary.
Definition: ExprCXX.h:1245
Represents a new-expression for memory allocation and constructor calls, e.g: "new CXXNewExpr(foo)"...
Definition: ExprCXX.h:2000
Expr * getLHS()
Definition: Stmt.h:1552
void setLabel(Stmt *Statement)
Definition: CFG.h:854
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:4751
ASTContext & getASTContext() const LLVM_READONLY
Definition: DeclBase.cpp:376
iterator insertScopeEnd(iterator I, VarDecl *VD, Stmt *S)
Definition: CFG.h:1001
Stmt * getElse()
Definition: Stmt.h:1893
DeclStmt - Adaptor class for mixing declarations with statements and expressions. ...
Definition: Stmt.h:1203
bool PruneTriviallyFalseEdges
Definition: CFG.h:1041
reverse_body_iterator body_rend()
Definition: Stmt.h:1384
QualType getBaseElementType(const ArrayType *VAT) const
Return the innermost element type of an array type.
const ConstantArrayType * getAsConstantArrayType(QualType T) const
Definition: ASTContext.h:2441
Expr * getCond()
Definition: Stmt.h:2062
virtual void compareAlwaysTrue(const BinaryOperator *B, bool isAlwaysTrue)
Definition: CFG.h:1015
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:5374
__m64_union t
Definition: emmintrin.h:2059
const ArrayType * getAsArrayType(QualType T) const
Type Query functions.
A branch in control flow of destructors of temporaries.
Definition: CFG.h:506
bool isArray() const
Definition: ExprCXX.h:2124
decl_iterator decl_begin()
Definition: Stmt.h:1257
bool isValueDependent() const
isValueDependent - Determines whether this expression is value-dependent (C++ [temp.dep.constexpr]).
Definition: Expr.h:158
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:1264
ImplicitCastExpr - Allows us to explicitly represent implicit type conversions, which have no direct ...
Definition: Expr.h:3245
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:2757
Expr ** getInits()
Retrieve the set of initializers.
Definition: Expr.h:4404
void appendScopeBegin(const VarDecl *VD, const Stmt *S, BumpVectorContext &C)
Definition: CFG.h:922
iterator begin()
Definition: CFG.h:1103
static bool isLogicalOp(Opcode Opc)
Definition: Expr.h:3528
static const Expr * tryTransformToIntOrEnumConstant(const Expr *E)
Helper for tryNormalizeBinaryOperator.
Definition: CFG.cpp:75
bool isValid() const
Definition: CFG.h:528
VarDecl * getConditionVariable()
Retrieve the variable declared in this "switch" statement, if any.
Definition: Stmt.cpp:976
DeclStmt * getConditionVariableDeclStmt()
If this WhileStmt has a condition variable, return the faux DeclStmt associated with the creation of ...
Definition: Stmt.h:2274
void dump() const
Definition: CFG.cpp:5587
succ_iterator succ_end()
Definition: CFG.h:770
StmtExpr - This is the GNU Statement Expression extension: ({int X=4; X;}).
Definition: Expr.h:3922
bool isArgumentType() const
Definition: Expr.h:2378
Represents end of a scope implicitly generated by the compiler after the last Stmt in a CompoundStmt&#39;...
Definition: CFG.h:335