clang  10.0.0svn
CFG.cpp
Go to the documentation of this file.
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, bool ExternallyDestructed);
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,
550  AddStmtChoice asc, bool ExternallyDestructed);
551  CFGBlock *VisitForStmt(ForStmt *F);
552  CFGBlock *VisitGotoStmt(GotoStmt *G);
553  CFGBlock *VisitGCCAsmStmt(GCCAsmStmt *G, AddStmtChoice asc);
554  CFGBlock *VisitIfStmt(IfStmt *I);
555  CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc);
556  CFGBlock *VisitConstantExpr(ConstantExpr *E, AddStmtChoice asc);
557  CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I);
558  CFGBlock *VisitLabelStmt(LabelStmt *L);
559  CFGBlock *VisitBlockExpr(BlockExpr *E, AddStmtChoice asc);
560  CFGBlock *VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc);
561  CFGBlock *VisitLogicalOperator(BinaryOperator *B);
562  std::pair<CFGBlock *, CFGBlock *> VisitLogicalOperator(BinaryOperator *B,
563  Stmt *Term,
564  CFGBlock *TrueBlock,
565  CFGBlock *FalseBlock);
566  CFGBlock *VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *MTE,
567  AddStmtChoice asc);
568  CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc);
569  CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S);
570  CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S);
571  CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S);
572  CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S);
573  CFGBlock *VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S);
574  CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S);
575  CFGBlock *VisitObjCMessageExpr(ObjCMessageExpr *E, AddStmtChoice asc);
576  CFGBlock *VisitPseudoObjectExpr(PseudoObjectExpr *E);
577  CFGBlock *VisitReturnStmt(Stmt *S);
578  CFGBlock *VisitSEHExceptStmt(SEHExceptStmt *S);
579  CFGBlock *VisitSEHFinallyStmt(SEHFinallyStmt *S);
580  CFGBlock *VisitSEHLeaveStmt(SEHLeaveStmt *S);
581  CFGBlock *VisitSEHTryStmt(SEHTryStmt *S);
582  CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc);
583  CFGBlock *VisitSwitchStmt(SwitchStmt *S);
584  CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
585  AddStmtChoice asc);
586  CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc);
587  CFGBlock *VisitWhileStmt(WhileStmt *W);
588 
589  CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd,
590  bool ExternallyDestructed = false);
591  CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc);
592  CFGBlock *VisitChildren(Stmt *S);
593  CFGBlock *VisitNoRecurse(Expr *E, AddStmtChoice asc);
594  CFGBlock *VisitOMPExecutableDirective(OMPExecutableDirective *D,
595  AddStmtChoice asc);
596 
597  void maybeAddScopeBeginForVarDecl(CFGBlock *B, const VarDecl *VD,
598  const Stmt *S) {
599  if (ScopePos && (VD == ScopePos.getFirstVarInScope()))
600  appendScopeBegin(B, VD, S);
601  }
602 
603  /// When creating the CFG for temporary destructors, we want to mirror the
604  /// branch structure of the corresponding constructor calls.
605  /// Thus, while visiting a statement for temporary destructors, we keep a
606  /// context to keep track of the following information:
607  /// - whether a subexpression is executed unconditionally
608  /// - if a subexpression is executed conditionally, the first
609  /// CXXBindTemporaryExpr we encounter in that subexpression (which
610  /// corresponds to the last temporary destructor we have to call for this
611  /// subexpression) and the CFG block at that point (which will become the
612  /// successor block when inserting the decision point).
613  ///
614  /// That way, we can build the branch structure for temporary destructors as
615  /// follows:
616  /// 1. If a subexpression is executed unconditionally, we add the temporary
617  /// destructor calls to the current block.
618  /// 2. If a subexpression is executed conditionally, when we encounter a
619  /// CXXBindTemporaryExpr:
620  /// a) If it is the first temporary destructor call in the subexpression,
621  /// we remember the CXXBindTemporaryExpr and the current block in the
622  /// TempDtorContext; we start a new block, and insert the temporary
623  /// destructor call.
624  /// b) Otherwise, add the temporary destructor call to the current block.
625  /// 3. When we finished visiting a conditionally executed subexpression,
626  /// and we found at least one temporary constructor during the visitation
627  /// (2.a has executed), we insert a decision block that uses the
628  /// CXXBindTemporaryExpr as terminator, and branches to the current block
629  /// if the CXXBindTemporaryExpr was marked executed, and otherwise
630  /// branches to the stored successor.
631  struct TempDtorContext {
632  TempDtorContext() = default;
633  TempDtorContext(TryResult KnownExecuted)
634  : IsConditional(true), KnownExecuted(KnownExecuted) {}
635 
636  /// Returns whether we need to start a new branch for a temporary destructor
637  /// call. This is the case when the temporary destructor is
638  /// conditionally executed, and it is the first one we encounter while
639  /// visiting a subexpression - other temporary destructors at the same level
640  /// will be added to the same block and are executed under the same
641  /// condition.
642  bool needsTempDtorBranch() const {
643  return IsConditional && !TerminatorExpr;
644  }
645 
646  /// Remember the successor S of a temporary destructor decision branch for
647  /// the corresponding CXXBindTemporaryExpr E.
648  void setDecisionPoint(CFGBlock *S, CXXBindTemporaryExpr *E) {
649  Succ = S;
650  TerminatorExpr = E;
651  }
652 
653  const bool IsConditional = false;
654  const TryResult KnownExecuted = true;
655  CFGBlock *Succ = nullptr;
656  CXXBindTemporaryExpr *TerminatorExpr = nullptr;
657  };
658 
659  // Visitors to walk an AST and generate destructors of temporaries in
660  // full expression.
661  CFGBlock *VisitForTemporaryDtors(Stmt *E, bool ExternallyDestructed,
662  TempDtorContext &Context);
663  CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E, bool ExternallyDestructed,
664  TempDtorContext &Context);
665  CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E,
666  bool ExternallyDestructed,
667  TempDtorContext &Context);
668  CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(
669  CXXBindTemporaryExpr *E, bool ExternallyDestructed, TempDtorContext &Context);
670  CFGBlock *VisitConditionalOperatorForTemporaryDtors(
671  AbstractConditionalOperator *E, bool ExternallyDestructed,
672  TempDtorContext &Context);
673  void InsertTempDtorDecisionBlock(const TempDtorContext &Context,
674  CFGBlock *FalseSucc = nullptr);
675 
676  // NYS == Not Yet Supported
677  CFGBlock *NYS() {
678  badCFG = true;
679  return Block;
680  }
681 
682  // Remember to apply the construction context based on the current \p Layer
683  // when constructing the CFG element for \p CE.
684  void consumeConstructionContext(const ConstructionContextLayer *Layer,
685  Expr *E);
686 
687  // Scan \p Child statement to find constructors in it, while keeping in mind
688  // that its parent statement is providing a partial construction context
689  // described by \p Layer. If a constructor is found, it would be assigned
690  // the context based on the layer. If an additional construction context layer
691  // is found, the function recurses into that.
692  void findConstructionContexts(const ConstructionContextLayer *Layer,
693  Stmt *Child);
694 
695  // Scan all arguments of a call expression for a construction context.
696  // These sorts of call expressions don't have a common superclass,
697  // hence strict duck-typing.
698  template <typename CallLikeExpr,
699  typename = typename std::enable_if<
700  std::is_same<CallLikeExpr, CallExpr>::value ||
701  std::is_same<CallLikeExpr, CXXConstructExpr>::value ||
702  std::is_same<CallLikeExpr, ObjCMessageExpr>::value>>
703  void findConstructionContextsForArguments(CallLikeExpr *E) {
704  for (unsigned i = 0, e = E->getNumArgs(); i != e; ++i) {
705  Expr *Arg = E->getArg(i);
706  if (Arg->getType()->getAsCXXRecordDecl() && !Arg->isGLValue())
707  findConstructionContexts(
708  ConstructionContextLayer::create(cfg->getBumpVectorContext(),
710  Arg);
711  }
712  }
713 
714  // Unset the construction context after consuming it. This is done immediately
715  // after adding the CFGConstructor or CFGCXXRecordTypedCall element, so
716  // there's no need to do this manually in every Visit... function.
717  void cleanupConstructionContext(Expr *E);
718 
719  void autoCreateBlock() { if (!Block) Block = createBlock(); }
720  CFGBlock *createBlock(bool add_successor = true);
721  CFGBlock *createNoReturnBlock();
722 
723  CFGBlock *addStmt(Stmt *S) {
724  return Visit(S, AddStmtChoice::AlwaysAdd);
725  }
726 
727  CFGBlock *addInitializer(CXXCtorInitializer *I);
728  void addLoopExit(const Stmt *LoopStmt);
729  void addAutomaticObjDtors(LocalScope::const_iterator B,
730  LocalScope::const_iterator E, Stmt *S);
731  void addLifetimeEnds(LocalScope::const_iterator B,
732  LocalScope::const_iterator E, Stmt *S);
733  void addAutomaticObjHandling(LocalScope::const_iterator B,
734  LocalScope::const_iterator E, Stmt *S);
735  void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD);
736  void addScopesEnd(LocalScope::const_iterator B, LocalScope::const_iterator E,
737  Stmt *S);
738 
739  void getDeclsWithEndedScope(LocalScope::const_iterator B,
740  LocalScope::const_iterator E, Stmt *S);
741 
742  // Local scopes creation.
743  LocalScope* createOrReuseLocalScope(LocalScope* Scope);
744 
745  void addLocalScopeForStmt(Stmt *S);
746  LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS,
747  LocalScope* Scope = nullptr);
748  LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = nullptr);
749 
750  void addLocalScopeAndDtors(Stmt *S);
751 
752  const ConstructionContext *retrieveAndCleanupConstructionContext(Expr *E) {
753  if (!BuildOpts.AddRichCXXConstructors)
754  return nullptr;
755 
756  const ConstructionContextLayer *Layer = ConstructionContextMap.lookup(E);
757  if (!Layer)
758  return nullptr;
759 
760  cleanupConstructionContext(E);
761  return ConstructionContext::createFromLayers(cfg->getBumpVectorContext(),
762  Layer);
763  }
764 
765  // Interface to CFGBlock - adding CFGElements.
766 
767  void appendStmt(CFGBlock *B, const Stmt *S) {
768  if (alwaysAdd(S) && cachedEntry)
769  cachedEntry->second = B;
770 
771  // All block-level expressions should have already been IgnoreParens()ed.
772  assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S);
773  B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext());
774  }
775 
776  void appendConstructor(CFGBlock *B, CXXConstructExpr *CE) {
777  if (const ConstructionContext *CC =
778  retrieveAndCleanupConstructionContext(CE)) {
779  B->appendConstructor(CE, CC, cfg->getBumpVectorContext());
780  return;
781  }
782 
783  // No valid construction context found. Fall back to statement.
784  B->appendStmt(CE, cfg->getBumpVectorContext());
785  }
786 
787  void appendCall(CFGBlock *B, CallExpr *CE) {
788  if (alwaysAdd(CE) && cachedEntry)
789  cachedEntry->second = B;
790 
791  if (const ConstructionContext *CC =
792  retrieveAndCleanupConstructionContext(CE)) {
793  B->appendCXXRecordTypedCall(CE, CC, cfg->getBumpVectorContext());
794  return;
795  }
796 
797  // No valid construction context found. Fall back to statement.
798  B->appendStmt(CE, cfg->getBumpVectorContext());
799  }
800 
801  void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) {
802  B->appendInitializer(I, cfg->getBumpVectorContext());
803  }
804 
805  void appendNewAllocator(CFGBlock *B, CXXNewExpr *NE) {
806  B->appendNewAllocator(NE, cfg->getBumpVectorContext());
807  }
808 
809  void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) {
810  B->appendBaseDtor(BS, cfg->getBumpVectorContext());
811  }
812 
813  void appendMemberDtor(CFGBlock *B, FieldDecl *FD) {
814  B->appendMemberDtor(FD, cfg->getBumpVectorContext());
815  }
816 
817  void appendObjCMessage(CFGBlock *B, ObjCMessageExpr *ME) {
818  if (alwaysAdd(ME) && cachedEntry)
819  cachedEntry->second = B;
820 
821  if (const ConstructionContext *CC =
822  retrieveAndCleanupConstructionContext(ME)) {
823  B->appendCXXRecordTypedCall(ME, CC, cfg->getBumpVectorContext());
824  return;
825  }
826 
827  B->appendStmt(const_cast<ObjCMessageExpr *>(ME),
828  cfg->getBumpVectorContext());
829  }
830 
831  void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) {
832  B->appendTemporaryDtor(E, cfg->getBumpVectorContext());
833  }
834 
835  void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) {
836  B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext());
837  }
838 
839  void appendLifetimeEnds(CFGBlock *B, VarDecl *VD, Stmt *S) {
840  B->appendLifetimeEnds(VD, S, cfg->getBumpVectorContext());
841  }
842 
843  void appendLoopExit(CFGBlock *B, const Stmt *LoopStmt) {
844  B->appendLoopExit(LoopStmt, cfg->getBumpVectorContext());
845  }
846 
847  void appendDeleteDtor(CFGBlock *B, CXXRecordDecl *RD, CXXDeleteExpr *DE) {
848  B->appendDeleteDtor(RD, DE, cfg->getBumpVectorContext());
849  }
850 
851  void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
852  LocalScope::const_iterator B, LocalScope::const_iterator E);
853 
854  void prependAutomaticObjLifetimeWithTerminator(CFGBlock *Blk,
855  LocalScope::const_iterator B,
856  LocalScope::const_iterator E);
857 
858  const VarDecl *
859  prependAutomaticObjScopeEndWithTerminator(CFGBlock *Blk,
860  LocalScope::const_iterator B,
861  LocalScope::const_iterator E);
862 
863  void addSuccessor(CFGBlock *B, CFGBlock *S, bool IsReachable = true) {
864  B->addSuccessor(CFGBlock::AdjacentBlock(S, IsReachable),
865  cfg->getBumpVectorContext());
866  }
867 
868  /// Add a reachable successor to a block, with the alternate variant that is
869  /// unreachable.
870  void addSuccessor(CFGBlock *B, CFGBlock *ReachableBlock, CFGBlock *AltBlock) {
871  B->addSuccessor(CFGBlock::AdjacentBlock(ReachableBlock, AltBlock),
872  cfg->getBumpVectorContext());
873  }
874 
875  void appendScopeBegin(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
876  if (BuildOpts.AddScopes)
877  B->appendScopeBegin(VD, S, cfg->getBumpVectorContext());
878  }
879 
880  void prependScopeBegin(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
881  if (BuildOpts.AddScopes)
882  B->prependScopeBegin(VD, S, cfg->getBumpVectorContext());
883  }
884 
885  void appendScopeEnd(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
886  if (BuildOpts.AddScopes)
887  B->appendScopeEnd(VD, S, cfg->getBumpVectorContext());
888  }
889 
890  void prependScopeEnd(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
891  if (BuildOpts.AddScopes)
892  B->prependScopeEnd(VD, S, cfg->getBumpVectorContext());
893  }
894 
895  /// Find a relational comparison with an expression evaluating to a
896  /// boolean and a constant other than 0 and 1.
897  /// e.g. if ((x < y) == 10)
898  TryResult checkIncorrectRelationalOperator(const BinaryOperator *B) {
899  const Expr *LHSExpr = B->getLHS()->IgnoreParens();
900  const Expr *RHSExpr = B->getRHS()->IgnoreParens();
901 
902  const IntegerLiteral *IntLiteral = dyn_cast<IntegerLiteral>(LHSExpr);
903  const Expr *BoolExpr = RHSExpr;
904  bool IntFirst = true;
905  if (!IntLiteral) {
906  IntLiteral = dyn_cast<IntegerLiteral>(RHSExpr);
907  BoolExpr = LHSExpr;
908  IntFirst = false;
909  }
910 
911  if (!IntLiteral || !BoolExpr->isKnownToHaveBooleanValue())
912  return TryResult();
913 
914  llvm::APInt IntValue = IntLiteral->getValue();
915  if ((IntValue == 1) || (IntValue == 0))
916  return TryResult();
917 
918  bool IntLarger = IntLiteral->getType()->isUnsignedIntegerType() ||
919  !IntValue.isNegative();
920 
921  BinaryOperatorKind Bok = B->getOpcode();
922  if (Bok == BO_GT || Bok == BO_GE) {
923  // Always true for 10 > bool and bool > -1
924  // Always false for -1 > bool and bool > 10
925  return TryResult(IntFirst == IntLarger);
926  } else {
927  // Always true for -1 < bool and bool < 10
928  // Always false for 10 < bool and bool < -1
929  return TryResult(IntFirst != IntLarger);
930  }
931  }
932 
933  /// Find an incorrect equality comparison. Either with an expression
934  /// evaluating to a boolean and a constant other than 0 and 1.
935  /// e.g. if (!x == 10) or a bitwise and/or operation that always evaluates to
936  /// true/false e.q. (x & 8) == 4.
937  TryResult checkIncorrectEqualityOperator(const BinaryOperator *B) {
938  const Expr *LHSExpr = B->getLHS()->IgnoreParens();
939  const Expr *RHSExpr = B->getRHS()->IgnoreParens();
940 
941  const IntegerLiteral *IntLiteral = dyn_cast<IntegerLiteral>(LHSExpr);
942  const Expr *BoolExpr = RHSExpr;
943 
944  if (!IntLiteral) {
945  IntLiteral = dyn_cast<IntegerLiteral>(RHSExpr);
946  BoolExpr = LHSExpr;
947  }
948 
949  if (!IntLiteral)
950  return TryResult();
951 
952  const BinaryOperator *BitOp = dyn_cast<BinaryOperator>(BoolExpr);
953  if (BitOp && (BitOp->getOpcode() == BO_And ||
954  BitOp->getOpcode() == BO_Or)) {
955  const Expr *LHSExpr2 = BitOp->getLHS()->IgnoreParens();
956  const Expr *RHSExpr2 = BitOp->getRHS()->IgnoreParens();
957 
958  const IntegerLiteral *IntLiteral2 = dyn_cast<IntegerLiteral>(LHSExpr2);
959 
960  if (!IntLiteral2)
961  IntLiteral2 = dyn_cast<IntegerLiteral>(RHSExpr2);
962 
963  if (!IntLiteral2)
964  return TryResult();
965 
966  llvm::APInt L1 = IntLiteral->getValue();
967  llvm::APInt L2 = IntLiteral2->getValue();
968  if ((BitOp->getOpcode() == BO_And && (L2 & L1) != L1) ||
969  (BitOp->getOpcode() == BO_Or && (L2 | L1) != L1)) {
970  if (BuildOpts.Observer)
971  BuildOpts.Observer->compareBitwiseEquality(B,
972  B->getOpcode() != BO_EQ);
973  TryResult(B->getOpcode() != BO_EQ);
974  }
975  } else if (BoolExpr->isKnownToHaveBooleanValue()) {
976  llvm::APInt IntValue = IntLiteral->getValue();
977  if ((IntValue == 1) || (IntValue == 0)) {
978  return TryResult();
979  }
980  return TryResult(B->getOpcode() != BO_EQ);
981  }
982 
983  return TryResult();
984  }
985 
986  TryResult analyzeLogicOperatorCondition(BinaryOperatorKind Relation,
987  const llvm::APSInt &Value1,
988  const llvm::APSInt &Value2) {
989  assert(Value1.isSigned() == Value2.isSigned());
990  switch (Relation) {
991  default:
992  return TryResult();
993  case BO_EQ:
994  return TryResult(Value1 == Value2);
995  case BO_NE:
996  return TryResult(Value1 != Value2);
997  case BO_LT:
998  return TryResult(Value1 < Value2);
999  case BO_LE:
1000  return TryResult(Value1 <= Value2);
1001  case BO_GT:
1002  return TryResult(Value1 > Value2);
1003  case BO_GE:
1004  return TryResult(Value1 >= Value2);
1005  }
1006  }
1007 
1008  /// Find a pair of comparison expressions with or without parentheses
1009  /// with a shared variable and constants and a logical operator between them
1010  /// that always evaluates to either true or false.
1011  /// e.g. if (x != 3 || x != 4)
1012  TryResult checkIncorrectLogicOperator(const BinaryOperator *B) {
1013  assert(B->isLogicalOp());
1014  const BinaryOperator *LHS =
1015  dyn_cast<BinaryOperator>(B->getLHS()->IgnoreParens());
1016  const BinaryOperator *RHS =
1017  dyn_cast<BinaryOperator>(B->getRHS()->IgnoreParens());
1018  if (!LHS || !RHS)
1019  return {};
1020 
1021  if (!LHS->isComparisonOp() || !RHS->isComparisonOp())
1022  return {};
1023 
1024  const DeclRefExpr *Decl1;
1025  const Expr *Expr1;
1026  BinaryOperatorKind BO1;
1027  std::tie(Decl1, BO1, Expr1) = tryNormalizeBinaryOperator(LHS);
1028 
1029  if (!Decl1 || !Expr1)
1030  return {};
1031 
1032  const DeclRefExpr *Decl2;
1033  const Expr *Expr2;
1034  BinaryOperatorKind BO2;
1035  std::tie(Decl2, BO2, Expr2) = tryNormalizeBinaryOperator(RHS);
1036 
1037  if (!Decl2 || !Expr2)
1038  return {};
1039 
1040  // Check that it is the same variable on both sides.
1041  if (Decl1->getDecl() != Decl2->getDecl())
1042  return {};
1043 
1044  // Make sure the user's intent is clear (e.g. they're comparing against two
1045  // int literals, or two things from the same enum)
1046  if (!areExprTypesCompatible(Expr1, Expr2))
1047  return {};
1048 
1049  Expr::EvalResult L1Result, L2Result;
1050  if (!Expr1->EvaluateAsInt(L1Result, *Context) ||
1051  !Expr2->EvaluateAsInt(L2Result, *Context))
1052  return {};
1053 
1054  llvm::APSInt L1 = L1Result.Val.getInt();
1055  llvm::APSInt L2 = L2Result.Val.getInt();
1056 
1057  // Can't compare signed with unsigned or with different bit width.
1058  if (L1.isSigned() != L2.isSigned() || L1.getBitWidth() != L2.getBitWidth())
1059  return {};
1060 
1061  // Values that will be used to determine if result of logical
1062  // operator is always true/false
1063  const llvm::APSInt Values[] = {
1064  // Value less than both Value1 and Value2
1065  llvm::APSInt::getMinValue(L1.getBitWidth(), L1.isUnsigned()),
1066  // L1
1067  L1,
1068  // Value between Value1 and Value2
1069  ((L1 < L2) ? L1 : L2) + llvm::APSInt(llvm::APInt(L1.getBitWidth(), 1),
1070  L1.isUnsigned()),
1071  // L2
1072  L2,
1073  // Value greater than both Value1 and Value2
1074  llvm::APSInt::getMaxValue(L1.getBitWidth(), L1.isUnsigned()),
1075  };
1076 
1077  // Check whether expression is always true/false by evaluating the following
1078  // * variable x is less than the smallest literal.
1079  // * variable x is equal to the smallest literal.
1080  // * Variable x is between smallest and largest literal.
1081  // * Variable x is equal to the largest literal.
1082  // * Variable x is greater than largest literal.
1083  bool AlwaysTrue = true, AlwaysFalse = true;
1084  for (const llvm::APSInt &Value : Values) {
1085  TryResult Res1, Res2;
1086  Res1 = analyzeLogicOperatorCondition(BO1, Value, L1);
1087  Res2 = analyzeLogicOperatorCondition(BO2, Value, L2);
1088 
1089  if (!Res1.isKnown() || !Res2.isKnown())
1090  return {};
1091 
1092  if (B->getOpcode() == BO_LAnd) {
1093  AlwaysTrue &= (Res1.isTrue() && Res2.isTrue());
1094  AlwaysFalse &= !(Res1.isTrue() && Res2.isTrue());
1095  } else {
1096  AlwaysTrue &= (Res1.isTrue() || Res2.isTrue());
1097  AlwaysFalse &= !(Res1.isTrue() || Res2.isTrue());
1098  }
1099  }
1100 
1101  if (AlwaysTrue || AlwaysFalse) {
1102  if (BuildOpts.Observer)
1103  BuildOpts.Observer->compareAlwaysTrue(B, AlwaysTrue);
1104  return TryResult(AlwaysTrue);
1105  }
1106  return {};
1107  }
1108 
1109  /// Try and evaluate an expression to an integer constant.
1110  bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) {
1111  if (!BuildOpts.PruneTriviallyFalseEdges)
1112  return false;
1113  return !S->isTypeDependent() &&
1114  !S->isValueDependent() &&
1115  S->EvaluateAsRValue(outResult, *Context);
1116  }
1117 
1118  /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1
1119  /// if we can evaluate to a known value, otherwise return -1.
1120  TryResult tryEvaluateBool(Expr *S) {
1121  if (!BuildOpts.PruneTriviallyFalseEdges ||
1122  S->isTypeDependent() || S->isValueDependent())
1123  return {};
1124 
1125  if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(S)) {
1126  if (Bop->isLogicalOp()) {
1127  // Check the cache first.
1128  CachedBoolEvalsTy::iterator I = CachedBoolEvals.find(S);
1129  if (I != CachedBoolEvals.end())
1130  return I->second; // already in map;
1131 
1132  // Retrieve result at first, or the map might be updated.
1133  TryResult Result = evaluateAsBooleanConditionNoCache(S);
1134  CachedBoolEvals[S] = Result; // update or insert
1135  return Result;
1136  }
1137  else {
1138  switch (Bop->getOpcode()) {
1139  default: break;
1140  // For 'x & 0' and 'x * 0', we can determine that
1141  // the value is always false.
1142  case BO_Mul:
1143  case BO_And: {
1144  // If either operand is zero, we know the value
1145  // must be false.
1146  Expr::EvalResult LHSResult;
1147  if (Bop->getLHS()->EvaluateAsInt(LHSResult, *Context)) {
1148  llvm::APSInt IntVal = LHSResult.Val.getInt();
1149  if (!IntVal.getBoolValue()) {
1150  return TryResult(false);
1151  }
1152  }
1153  Expr::EvalResult RHSResult;
1154  if (Bop->getRHS()->EvaluateAsInt(RHSResult, *Context)) {
1155  llvm::APSInt IntVal = RHSResult.Val.getInt();
1156  if (!IntVal.getBoolValue()) {
1157  return TryResult(false);
1158  }
1159  }
1160  }
1161  break;
1162  }
1163  }
1164  }
1165 
1166  return evaluateAsBooleanConditionNoCache(S);
1167  }
1168 
1169  /// Evaluate as boolean \param E without using the cache.
1170  TryResult evaluateAsBooleanConditionNoCache(Expr *E) {
1171  if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(E)) {
1172  if (Bop->isLogicalOp()) {
1173  TryResult LHS = tryEvaluateBool(Bop->getLHS());
1174  if (LHS.isKnown()) {
1175  // We were able to evaluate the LHS, see if we can get away with not
1176  // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
1177  if (LHS.isTrue() == (Bop->getOpcode() == BO_LOr))
1178  return LHS.isTrue();
1179 
1180  TryResult RHS = tryEvaluateBool(Bop->getRHS());
1181  if (RHS.isKnown()) {
1182  if (Bop->getOpcode() == BO_LOr)
1183  return LHS.isTrue() || RHS.isTrue();
1184  else
1185  return LHS.isTrue() && RHS.isTrue();
1186  }
1187  } else {
1188  TryResult RHS = tryEvaluateBool(Bop->getRHS());
1189  if (RHS.isKnown()) {
1190  // We can't evaluate the LHS; however, sometimes the result
1191  // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
1192  if (RHS.isTrue() == (Bop->getOpcode() == BO_LOr))
1193  return RHS.isTrue();
1194  } else {
1195  TryResult BopRes = checkIncorrectLogicOperator(Bop);
1196  if (BopRes.isKnown())
1197  return BopRes.isTrue();
1198  }
1199  }
1200 
1201  return {};
1202  } else if (Bop->isEqualityOp()) {
1203  TryResult BopRes = checkIncorrectEqualityOperator(Bop);
1204  if (BopRes.isKnown())
1205  return BopRes.isTrue();
1206  } else if (Bop->isRelationalOp()) {
1207  TryResult BopRes = checkIncorrectRelationalOperator(Bop);
1208  if (BopRes.isKnown())
1209  return BopRes.isTrue();
1210  }
1211  }
1212 
1213  bool Result;
1214  if (E->EvaluateAsBooleanCondition(Result, *Context))
1215  return Result;
1216 
1217  return {};
1218  }
1219 
1220  bool hasTrivialDestructor(VarDecl *VD);
1221 };
1222 
1223 } // namespace
1224 
1225 inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder,
1226  const Stmt *stmt) const {
1227  return builder.alwaysAdd(stmt) || kind == AlwaysAdd;
1228 }
1229 
1230 bool CFGBuilder::alwaysAdd(const Stmt *stmt) {
1231  bool shouldAdd = BuildOpts.alwaysAdd(stmt);
1232 
1233  if (!BuildOpts.forcedBlkExprs)
1234  return shouldAdd;
1235 
1236  if (lastLookup == stmt) {
1237  if (cachedEntry) {
1238  assert(cachedEntry->first == stmt);
1239  return true;
1240  }
1241  return shouldAdd;
1242  }
1243 
1244  lastLookup = stmt;
1245 
1246  // Perform the lookup!
1247  CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs;
1248 
1249  if (!fb) {
1250  // No need to update 'cachedEntry', since it will always be null.
1251  assert(!cachedEntry);
1252  return shouldAdd;
1253  }
1254 
1255  CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt);
1256  if (itr == fb->end()) {
1257  cachedEntry = nullptr;
1258  return shouldAdd;
1259  }
1260 
1261  cachedEntry = &*itr;
1262  return true;
1263 }
1264 
1265 // FIXME: Add support for dependent-sized array types in C++?
1266 // Does it even make sense to build a CFG for an uninstantiated template?
1267 static const VariableArrayType *FindVA(const Type *t) {
1268  while (const ArrayType *vt = dyn_cast<ArrayType>(t)) {
1269  if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt))
1270  if (vat->getSizeExpr())
1271  return vat;
1272 
1273  t = vt->getElementType().getTypePtr();
1274  }
1275 
1276  return nullptr;
1277 }
1278 
1279 void CFGBuilder::consumeConstructionContext(
1280  const ConstructionContextLayer *Layer, Expr *E) {
1281  assert((isa<CXXConstructExpr>(E) || isa<CallExpr>(E) ||
1282  isa<ObjCMessageExpr>(E)) && "Expression cannot construct an object!");
1283  if (const ConstructionContextLayer *PreviouslyStoredLayer =
1284  ConstructionContextMap.lookup(E)) {
1285  (void)PreviouslyStoredLayer;
1286  // We might have visited this child when we were finding construction
1287  // contexts within its parents.
1288  assert(PreviouslyStoredLayer->isStrictlyMoreSpecificThan(Layer) &&
1289  "Already within a different construction context!");
1290  } else {
1291  ConstructionContextMap[E] = Layer;
1292  }
1293 }
1294 
1295 void CFGBuilder::findConstructionContexts(
1296  const ConstructionContextLayer *Layer, Stmt *Child) {
1297  if (!BuildOpts.AddRichCXXConstructors)
1298  return;
1299 
1300  if (!Child)
1301  return;
1302 
1303  auto withExtraLayer = [this, Layer](const ConstructionContextItem &Item) {
1304  return ConstructionContextLayer::create(cfg->getBumpVectorContext(), Item,
1305  Layer);
1306  };
1307 
1308  switch(Child->getStmtClass()) {
1309  case Stmt::CXXConstructExprClass:
1310  case Stmt::CXXTemporaryObjectExprClass: {
1311  // Support pre-C++17 copy elision AST.
1312  auto *CE = cast<CXXConstructExpr>(Child);
1313  if (BuildOpts.MarkElidedCXXConstructors && CE->isElidable()) {
1314  findConstructionContexts(withExtraLayer(CE), CE->getArg(0));
1315  }
1316 
1317  consumeConstructionContext(Layer, CE);
1318  break;
1319  }
1320  // FIXME: This, like the main visit, doesn't support CUDAKernelCallExpr.
1321  // FIXME: An isa<> would look much better but this whole switch is a
1322  // workaround for an internal compiler error in MSVC 2015 (see r326021).
1323  case Stmt::CallExprClass:
1324  case Stmt::CXXMemberCallExprClass:
1325  case Stmt::CXXOperatorCallExprClass:
1326  case Stmt::UserDefinedLiteralClass:
1327  case Stmt::ObjCMessageExprClass: {
1328  auto *E = cast<Expr>(Child);
1330  consumeConstructionContext(Layer, E);
1331  break;
1332  }
1333  case Stmt::ExprWithCleanupsClass: {
1334  auto *Cleanups = cast<ExprWithCleanups>(Child);
1335  findConstructionContexts(Layer, Cleanups->getSubExpr());
1336  break;
1337  }
1338  case Stmt::CXXFunctionalCastExprClass: {
1339  auto *Cast = cast<CXXFunctionalCastExpr>(Child);
1340  findConstructionContexts(Layer, Cast->getSubExpr());
1341  break;
1342  }
1343  case Stmt::ImplicitCastExprClass: {
1344  auto *Cast = cast<ImplicitCastExpr>(Child);
1345  // Should we support other implicit cast kinds?
1346  switch (Cast->getCastKind()) {
1347  case CK_NoOp:
1348  case CK_ConstructorConversion:
1349  findConstructionContexts(Layer, Cast->getSubExpr());
1350  break;
1351  default:
1352  break;
1353  }
1354  break;
1355  }
1356  case Stmt::CXXBindTemporaryExprClass: {
1357  auto *BTE = cast<CXXBindTemporaryExpr>(Child);
1358  findConstructionContexts(withExtraLayer(BTE), BTE->getSubExpr());
1359  break;
1360  }
1361  case Stmt::MaterializeTemporaryExprClass: {
1362  // Normally we don't want to search in MaterializeTemporaryExpr because
1363  // it indicates the beginning of a temporary object construction context,
1364  // so it shouldn't be found in the middle. However, if it is the beginning
1365  // of an elidable copy or move construction context, we need to include it.
1366  if (Layer->getItem().getKind() ==
1368  auto *MTE = cast<MaterializeTemporaryExpr>(Child);
1369  findConstructionContexts(withExtraLayer(MTE), MTE->GetTemporaryExpr());
1370  }
1371  break;
1372  }
1373  case Stmt::ConditionalOperatorClass: {
1374  auto *CO = cast<ConditionalOperator>(Child);
1375  if (Layer->getItem().getKind() !=
1377  // If the object returned by the conditional operator is not going to be a
1378  // temporary object that needs to be immediately materialized, then
1379  // it must be C++17 with its mandatory copy elision. Do not yet promise
1380  // to support this case.
1381  assert(!CO->getType()->getAsCXXRecordDecl() || CO->isGLValue() ||
1382  Context->getLangOpts().CPlusPlus17);
1383  break;
1384  }
1385  findConstructionContexts(Layer, CO->getLHS());
1386  findConstructionContexts(Layer, CO->getRHS());
1387  break;
1388  }
1389  case Stmt::InitListExprClass: {
1390  auto *ILE = cast<InitListExpr>(Child);
1391  if (ILE->isTransparent()) {
1392  findConstructionContexts(Layer, ILE->getInit(0));
1393  break;
1394  }
1395  // TODO: Handle other cases. For now, fail to find construction contexts.
1396  break;
1397  }
1398  default:
1399  break;
1400  }
1401 }
1402 
1403 void CFGBuilder::cleanupConstructionContext(Expr *E) {
1404  assert(BuildOpts.AddRichCXXConstructors &&
1405  "We should not be managing construction contexts!");
1406  assert(ConstructionContextMap.count(E) &&
1407  "Cannot exit construction context without the context!");
1408  ConstructionContextMap.erase(E);
1409 }
1410 
1411 
1412 /// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an
1413 /// arbitrary statement. Examples include a single expression or a function
1414 /// body (compound statement). The ownership of the returned CFG is
1415 /// transferred to the caller. If CFG construction fails, this method returns
1416 /// NULL.
1417 std::unique_ptr<CFG> CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) {
1418  assert(cfg.get());
1419  if (!Statement)
1420  return nullptr;
1421 
1422  // Create an empty block that will serve as the exit block for the CFG. Since
1423  // this is the first block added to the CFG, it will be implicitly registered
1424  // as the exit block.
1425  Succ = createBlock();
1426  assert(Succ == &cfg->getExit());
1427  Block = nullptr; // the EXIT block is empty. Create all other blocks lazily.
1428 
1429  assert(!(BuildOpts.AddImplicitDtors && BuildOpts.AddLifetime) &&
1430  "AddImplicitDtors and AddLifetime cannot be used at the same time");
1431 
1432  if (BuildOpts.AddImplicitDtors)
1433  if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D))
1434  addImplicitDtorsForDestructor(DD);
1435 
1436  // Visit the statements and create the CFG.
1437  CFGBlock *B = addStmt(Statement);
1438 
1439  if (badCFG)
1440  return nullptr;
1441 
1442  // For C++ constructor add initializers to CFG. Constructors of virtual bases
1443  // are ignored unless the object is of the most derived class.
1444  // class VBase { VBase() = default; VBase(int) {} };
1445  // class A : virtual public VBase { A() : VBase(0) {} };
1446  // class B : public A {};
1447  // B b; // Constructor calls in order: VBase(), A(), B().
1448  // // VBase(0) is ignored because A isn't the most derived class.
1449  // This may result in the virtual base(s) being already initialized at this
1450  // point, in which case we should jump right onto non-virtual bases and
1451  // fields. To handle this, make a CFG branch. We only need to add one such
1452  // branch per constructor, since the Standard states that all virtual bases
1453  // shall be initialized before non-virtual bases and direct data members.
1454  if (const auto *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) {
1455  CFGBlock *VBaseSucc = nullptr;
1456  for (auto *I : llvm::reverse(CD->inits())) {
1457  if (BuildOpts.AddVirtualBaseBranches && !VBaseSucc &&
1458  I->isBaseInitializer() && I->isBaseVirtual()) {
1459  // We've reached the first virtual base init while iterating in reverse
1460  // order. Make a new block for virtual base initializers so that we
1461  // could skip them.
1462  VBaseSucc = Succ = B ? B : &cfg->getExit();
1463  Block = createBlock();
1464  }
1465  B = addInitializer(I);
1466  if (badCFG)
1467  return nullptr;
1468  }
1469  if (VBaseSucc) {
1470  // Make a branch block for potentially skipping virtual base initializers.
1471  Succ = VBaseSucc;
1472  B = createBlock();
1473  B->setTerminator(
1475  addSuccessor(B, Block, true);
1476  }
1477  }
1478 
1479  if (B)
1480  Succ = B;
1481 
1482  // Backpatch the gotos whose label -> block mappings we didn't know when we
1483  // encountered them.
1484  for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(),
1485  E = BackpatchBlocks.end(); I != E; ++I ) {
1486 
1487  CFGBlock *B = I->block;
1488  if (auto *G = dyn_cast<GotoStmt>(B->getTerminator())) {
1489  LabelMapTy::iterator LI = LabelMap.find(G->getLabel());
1490  // If there is no target for the goto, then we are looking at an
1491  // incomplete AST. Handle this by not registering a successor.
1492  if (LI == LabelMap.end())
1493  continue;
1494  JumpTarget JT = LI->second;
1495  prependAutomaticObjLifetimeWithTerminator(B, I->scopePosition,
1496  JT.scopePosition);
1497  prependAutomaticObjDtorsWithTerminator(B, I->scopePosition,
1498  JT.scopePosition);
1499  const VarDecl *VD = prependAutomaticObjScopeEndWithTerminator(
1500  B, I->scopePosition, JT.scopePosition);
1501  appendScopeBegin(JT.block, VD, G);
1502  addSuccessor(B, JT.block);
1503  };
1504  if (auto *G = dyn_cast<GCCAsmStmt>(B->getTerminator())) {
1505  CFGBlock *Successor = (I+1)->block;
1506  for (auto *L : G->labels()) {
1507  LabelMapTy::iterator LI = LabelMap.find(L->getLabel());
1508  // If there is no target for the goto, then we are looking at an
1509  // incomplete AST. Handle this by not registering a successor.
1510  if (LI == LabelMap.end())
1511  continue;
1512  JumpTarget JT = LI->second;
1513  // Successor has been added, so skip it.
1514  if (JT.block == Successor)
1515  continue;
1516  addSuccessor(B, JT.block);
1517  }
1518  I++;
1519  }
1520  }
1521 
1522  // Add successors to the Indirect Goto Dispatch block (if we have one).
1523  if (CFGBlock *B = cfg->getIndirectGotoBlock())
1524  for (LabelSetTy::iterator I = AddressTakenLabels.begin(),
1525  E = AddressTakenLabels.end(); I != E; ++I ) {
1526  // Lookup the target block.
1527  LabelMapTy::iterator LI = LabelMap.find(*I);
1528 
1529  // If there is no target block that contains label, then we are looking
1530  // at an incomplete AST. Handle this by not registering a successor.
1531  if (LI == LabelMap.end()) continue;
1532 
1533  addSuccessor(B, LI->second.block);
1534  }
1535 
1536  // Create an empty entry block that has no predecessors.
1537  cfg->setEntry(createBlock());
1538 
1539  if (BuildOpts.AddRichCXXConstructors)
1540  assert(ConstructionContextMap.empty() &&
1541  "Not all construction contexts were cleaned up!");
1542 
1543  return std::move(cfg);
1544 }
1545 
1546 /// createBlock - Used to lazily create blocks that are connected
1547 /// to the current (global) succcessor.
1548 CFGBlock *CFGBuilder::createBlock(bool add_successor) {
1549  CFGBlock *B = cfg->createBlock();
1550  if (add_successor && Succ)
1551  addSuccessor(B, Succ);
1552  return B;
1553 }
1554 
1555 /// createNoReturnBlock - Used to create a block is a 'noreturn' point in the
1556 /// CFG. It is *not* connected to the current (global) successor, and instead
1557 /// directly tied to the exit block in order to be reachable.
1558 CFGBlock *CFGBuilder::createNoReturnBlock() {
1559  CFGBlock *B = createBlock(false);
1560  B->setHasNoReturnElement();
1561  addSuccessor(B, &cfg->getExit(), Succ);
1562  return B;
1563 }
1564 
1565 /// addInitializer - Add C++ base or member initializer element to CFG.
1566 CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) {
1567  if (!BuildOpts.AddInitializers)
1568  return Block;
1569 
1570  bool HasTemporaries = false;
1571 
1572  // Destructors of temporaries in initialization expression should be called
1573  // after initialization finishes.
1574  Expr *Init = I->getInit();
1575  if (Init) {
1576  HasTemporaries = isa<ExprWithCleanups>(Init);
1577 
1578  if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
1579  // Generate destructors for temporaries in initialization expression.
1580  TempDtorContext Context;
1581  VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
1582  /*ExternallyDestructed=*/false, Context);
1583  }
1584  }
1585 
1586  autoCreateBlock();
1587  appendInitializer(Block, I);
1588 
1589  if (Init) {
1590  findConstructionContexts(
1591  ConstructionContextLayer::create(cfg->getBumpVectorContext(), I),
1592  Init);
1593 
1594  if (HasTemporaries) {
1595  // For expression with temporaries go directly to subexpression to omit
1596  // generating destructors for the second time.
1597  return Visit(cast<ExprWithCleanups>(Init)->getSubExpr());
1598  }
1599  if (BuildOpts.AddCXXDefaultInitExprInCtors) {
1600  if (CXXDefaultInitExpr *Default = dyn_cast<CXXDefaultInitExpr>(Init)) {
1601  // In general, appending the expression wrapped by a CXXDefaultInitExpr
1602  // may cause the same Expr to appear more than once in the CFG. Doing it
1603  // here is safe because there's only one initializer per field.
1604  autoCreateBlock();
1605  appendStmt(Block, Default);
1606  if (Stmt *Child = Default->getExpr())
1607  if (CFGBlock *R = Visit(Child))
1608  Block = R;
1609  return Block;
1610  }
1611  }
1612  return Visit(Init);
1613  }
1614 
1615  return Block;
1616 }
1617 
1618 /// Retrieve the type of the temporary object whose lifetime was
1619 /// extended by a local reference with the given initializer.
1621  bool *FoundMTE = nullptr) {
1622  while (true) {
1623  // Skip parentheses.
1624  Init = Init->IgnoreParens();
1625 
1626  // Skip through cleanups.
1627  if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Init)) {
1628  Init = EWC->getSubExpr();
1629  continue;
1630  }
1631 
1632  // Skip through the temporary-materialization expression.
1633  if (const MaterializeTemporaryExpr *MTE
1634  = dyn_cast<MaterializeTemporaryExpr>(Init)) {
1635  Init = MTE->GetTemporaryExpr();
1636  if (FoundMTE)
1637  *FoundMTE = true;
1638  continue;
1639  }
1640 
1641  // Skip sub-object accesses into rvalues.
1642  SmallVector<const Expr *, 2> CommaLHSs;
1644  const Expr *SkippedInit =
1645  Init->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
1646  if (SkippedInit != Init) {
1647  Init = SkippedInit;
1648  continue;
1649  }
1650 
1651  break;
1652  }
1653 
1654  return Init->getType();
1655 }
1656 
1657 // TODO: Support adding LoopExit element to the CFG in case where the loop is
1658 // ended by ReturnStmt, GotoStmt or ThrowExpr.
1659 void CFGBuilder::addLoopExit(const Stmt *LoopStmt){
1660  if(!BuildOpts.AddLoopExit)
1661  return;
1662  autoCreateBlock();
1663  appendLoopExit(Block, LoopStmt);
1664 }
1665 
1666 void CFGBuilder::getDeclsWithEndedScope(LocalScope::const_iterator B,
1667  LocalScope::const_iterator E, Stmt *S) {
1668  if (!BuildOpts.AddScopes)
1669  return;
1670 
1671  if (B == E)
1672  return;
1673 
1674  // To go from B to E, one first goes up the scopes from B to P
1675  // then sideways in one scope from P to P' and then down
1676  // the scopes from P' to E.
1677  // The lifetime of all objects between B and P end.
1678  LocalScope::const_iterator P = B.shared_parent(E);
1679  int Dist = B.distance(P);
1680  if (Dist <= 0)
1681  return;
1682 
1683  for (LocalScope::const_iterator I = B; I != P; ++I)
1684  if (I.pointsToFirstDeclaredVar())
1685  DeclsWithEndedScope.insert(*I);
1686 }
1687 
1688 void CFGBuilder::addAutomaticObjHandling(LocalScope::const_iterator B,
1689  LocalScope::const_iterator E,
1690  Stmt *S) {
1691  getDeclsWithEndedScope(B, E, S);
1692  if (BuildOpts.AddScopes)
1693  addScopesEnd(B, E, S);
1694  if (BuildOpts.AddImplicitDtors)
1695  addAutomaticObjDtors(B, E, S);
1696  if (BuildOpts.AddLifetime)
1697  addLifetimeEnds(B, E, S);
1698 }
1699 
1700 /// Add to current block automatic objects that leave the scope.
1701 void CFGBuilder::addLifetimeEnds(LocalScope::const_iterator B,
1702  LocalScope::const_iterator E, Stmt *S) {
1703  if (!BuildOpts.AddLifetime)
1704  return;
1705 
1706  if (B == E)
1707  return;
1708 
1709  // To go from B to E, one first goes up the scopes from B to P
1710  // then sideways in one scope from P to P' and then down
1711  // the scopes from P' to E.
1712  // The lifetime of all objects between B and P end.
1713  LocalScope::const_iterator P = B.shared_parent(E);
1714  int dist = B.distance(P);
1715  if (dist <= 0)
1716  return;
1717 
1718  // We need to perform the scope leaving in reverse order
1719  SmallVector<VarDecl *, 10> DeclsTrivial;
1720  SmallVector<VarDecl *, 10> DeclsNonTrivial;
1721  DeclsTrivial.reserve(dist);
1722  DeclsNonTrivial.reserve(dist);
1723 
1724  for (LocalScope::const_iterator I = B; I != P; ++I)
1725  if (hasTrivialDestructor(*I))
1726  DeclsTrivial.push_back(*I);
1727  else
1728  DeclsNonTrivial.push_back(*I);
1729 
1730  autoCreateBlock();
1731  // object with trivial destructor end their lifetime last (when storage
1732  // duration ends)
1733  for (SmallVectorImpl<VarDecl *>::reverse_iterator I = DeclsTrivial.rbegin(),
1734  E = DeclsTrivial.rend();
1735  I != E; ++I)
1736  appendLifetimeEnds(Block, *I, S);
1737 
1739  I = DeclsNonTrivial.rbegin(),
1740  E = DeclsNonTrivial.rend();
1741  I != E; ++I)
1742  appendLifetimeEnds(Block, *I, S);
1743 }
1744 
1745 /// Add to current block markers for ending scopes.
1746 void CFGBuilder::addScopesEnd(LocalScope::const_iterator B,
1747  LocalScope::const_iterator E, Stmt *S) {
1748  // If implicit destructors are enabled, we'll add scope ends in
1749  // addAutomaticObjDtors.
1750  if (BuildOpts.AddImplicitDtors)
1751  return;
1752 
1753  autoCreateBlock();
1754 
1755  for (auto I = DeclsWithEndedScope.rbegin(), E = DeclsWithEndedScope.rend();
1756  I != E; ++I)
1757  appendScopeEnd(Block, *I, S);
1758 
1759  return;
1760 }
1761 
1762 /// addAutomaticObjDtors - Add to current block automatic objects destructors
1763 /// for objects in range of local scope positions. Use S as trigger statement
1764 /// for destructors.
1765 void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B,
1766  LocalScope::const_iterator E, Stmt *S) {
1767  if (!BuildOpts.AddImplicitDtors)
1768  return;
1769 
1770  if (B == E)
1771  return;
1772 
1773  // We need to append the destructors in reverse order, but any one of them
1774  // may be a no-return destructor which changes the CFG. As a result, buffer
1775  // this sequence up and replay them in reverse order when appending onto the
1776  // CFGBlock(s).
1778  Decls.reserve(B.distance(E));
1779  for (LocalScope::const_iterator I = B; I != E; ++I)
1780  Decls.push_back(*I);
1781 
1782  for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(),
1783  E = Decls.rend();
1784  I != E; ++I) {
1785  if (hasTrivialDestructor(*I)) {
1786  // If AddScopes is enabled and *I is a first variable in a scope, add a
1787  // ScopeEnd marker in a Block.
1788  if (BuildOpts.AddScopes && DeclsWithEndedScope.count(*I)) {
1789  autoCreateBlock();
1790  appendScopeEnd(Block, *I, S);
1791  }
1792  continue;
1793  }
1794  // If this destructor is marked as a no-return destructor, we need to
1795  // create a new block for the destructor which does not have as a successor
1796  // anything built thus far: control won't flow out of this block.
1797  QualType Ty = (*I)->getType();
1798  if (Ty->isReferenceType()) {
1799  Ty = getReferenceInitTemporaryType((*I)->getInit());
1800  }
1801  Ty = Context->getBaseElementType(Ty);
1802 
1803  if (Ty->getAsCXXRecordDecl()->isAnyDestructorNoReturn())
1804  Block = createNoReturnBlock();
1805  else
1806  autoCreateBlock();
1807 
1808  // Add ScopeEnd just after automatic obj destructor.
1809  if (BuildOpts.AddScopes && DeclsWithEndedScope.count(*I))
1810  appendScopeEnd(Block, *I, S);
1811  appendAutomaticObjDtor(Block, *I, S);
1812  }
1813 }
1814 
1815 /// addImplicitDtorsForDestructor - Add implicit destructors generated for
1816 /// base and member objects in destructor.
1817 void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) {
1818  assert(BuildOpts.AddImplicitDtors &&
1819  "Can be called only when dtors should be added");
1820  const CXXRecordDecl *RD = DD->getParent();
1821 
1822  // At the end destroy virtual base objects.
1823  for (const auto &VI : RD->vbases()) {
1824  // TODO: Add a VirtualBaseBranch to see if the most derived class
1825  // (which is different from the current class) is responsible for
1826  // destroying them.
1827  const CXXRecordDecl *CD = VI.getType()->getAsCXXRecordDecl();
1828  if (!CD->hasTrivialDestructor()) {
1829  autoCreateBlock();
1830  appendBaseDtor(Block, &VI);
1831  }
1832  }
1833 
1834  // Before virtual bases destroy direct base objects.
1835  for (const auto &BI : RD->bases()) {
1836  if (!BI.isVirtual()) {
1837  const CXXRecordDecl *CD = BI.getType()->getAsCXXRecordDecl();
1838  if (!CD->hasTrivialDestructor()) {
1839  autoCreateBlock();
1840  appendBaseDtor(Block, &BI);
1841  }
1842  }
1843  }
1844 
1845  // First destroy member objects.
1846  for (auto *FI : RD->fields()) {
1847  // Check for constant size array. Set type to array element type.
1848  QualType QT = FI->getType();
1849  if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
1850  if (AT->getSize() == 0)
1851  continue;
1852  QT = AT->getElementType();
1853  }
1854 
1855  if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
1856  if (!CD->hasTrivialDestructor()) {
1857  autoCreateBlock();
1858  appendMemberDtor(Block, FI);
1859  }
1860  }
1861 }
1862 
1863 /// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either
1864 /// way return valid LocalScope object.
1865 LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) {
1866  if (Scope)
1867  return Scope;
1868  llvm::BumpPtrAllocator &alloc = cfg->getAllocator();
1869  return new (alloc.Allocate<LocalScope>())
1870  LocalScope(BumpVectorContext(alloc), ScopePos);
1871 }
1872 
1873 /// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement
1874 /// that should create implicit scope (e.g. if/else substatements).
1875 void CFGBuilder::addLocalScopeForStmt(Stmt *S) {
1876  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1877  !BuildOpts.AddScopes)
1878  return;
1879 
1880  LocalScope *Scope = nullptr;
1881 
1882  // For compound statement we will be creating explicit scope.
1883  if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
1884  for (auto *BI : CS->body()) {
1885  Stmt *SI = BI->stripLabelLikeStatements();
1886  if (DeclStmt *DS = dyn_cast<DeclStmt>(SI))
1887  Scope = addLocalScopeForDeclStmt(DS, Scope);
1888  }
1889  return;
1890  }
1891 
1892  // For any other statement scope will be implicit and as such will be
1893  // interesting only for DeclStmt.
1894  if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements()))
1895  addLocalScopeForDeclStmt(DS);
1896 }
1897 
1898 /// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will
1899 /// reuse Scope if not NULL.
1900 LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS,
1901  LocalScope* Scope) {
1902  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1903  !BuildOpts.AddScopes)
1904  return Scope;
1905 
1906  for (auto *DI : DS->decls())
1907  if (VarDecl *VD = dyn_cast<VarDecl>(DI))
1908  Scope = addLocalScopeForVarDecl(VD, Scope);
1909  return Scope;
1910 }
1911 
1912 bool CFGBuilder::hasTrivialDestructor(VarDecl *VD) {
1913  // Check for const references bound to temporary. Set type to pointee.
1914  QualType QT = VD->getType();
1915  if (QT->isReferenceType()) {
1916  // Attempt to determine whether this declaration lifetime-extends a
1917  // temporary.
1918  //
1919  // FIXME: This is incorrect. Non-reference declarations can lifetime-extend
1920  // temporaries, and a single declaration can extend multiple temporaries.
1921  // We should look at the storage duration on each nested
1922  // MaterializeTemporaryExpr instead.
1923 
1924  const Expr *Init = VD->getInit();
1925  if (!Init) {
1926  // Probably an exception catch-by-reference variable.
1927  // FIXME: It doesn't really mean that the object has a trivial destructor.
1928  // Also are there other cases?
1929  return true;
1930  }
1931 
1932  // Lifetime-extending a temporary?
1933  bool FoundMTE = false;
1934  QT = getReferenceInitTemporaryType(Init, &FoundMTE);
1935  if (!FoundMTE)
1936  return true;
1937  }
1938 
1939  // Check for constant size array. Set type to array element type.
1940  while (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
1941  if (AT->getSize() == 0)
1942  return true;
1943  QT = AT->getElementType();
1944  }
1945 
1946  // Check if type is a C++ class with non-trivial destructor.
1947  if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
1948  return !CD->hasDefinition() || CD->hasTrivialDestructor();
1949  return true;
1950 }
1951 
1952 /// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will
1953 /// create add scope for automatic objects and temporary objects bound to
1954 /// const reference. Will reuse Scope if not NULL.
1955 LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD,
1956  LocalScope* Scope) {
1957  assert(!(BuildOpts.AddImplicitDtors && BuildOpts.AddLifetime) &&
1958  "AddImplicitDtors and AddLifetime cannot be used at the same time");
1959  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1960  !BuildOpts.AddScopes)
1961  return Scope;
1962 
1963  // Check if variable is local.
1964  switch (VD->getStorageClass()) {
1965  case SC_None:
1966  case SC_Auto:
1967  case SC_Register:
1968  break;
1969  default: return Scope;
1970  }
1971 
1972  if (BuildOpts.AddImplicitDtors) {
1973  if (!hasTrivialDestructor(VD) || BuildOpts.AddScopes) {
1974  // Add the variable to scope
1975  Scope = createOrReuseLocalScope(Scope);
1976  Scope->addVar(VD);
1977  ScopePos = Scope->begin();
1978  }
1979  return Scope;
1980  }
1981 
1982  assert(BuildOpts.AddLifetime);
1983  // Add the variable to scope
1984  Scope = createOrReuseLocalScope(Scope);
1985  Scope->addVar(VD);
1986  ScopePos = Scope->begin();
1987  return Scope;
1988 }
1989 
1990 /// addLocalScopeAndDtors - For given statement add local scope for it and
1991 /// add destructors that will cleanup the scope. Will reuse Scope if not NULL.
1992 void CFGBuilder::addLocalScopeAndDtors(Stmt *S) {
1993  LocalScope::const_iterator scopeBeginPos = ScopePos;
1994  addLocalScopeForStmt(S);
1995  addAutomaticObjHandling(ScopePos, scopeBeginPos, S);
1996 }
1997 
1998 /// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for
1999 /// variables with automatic storage duration to CFGBlock's elements vector.
2000 /// Elements will be prepended to physical beginning of the vector which
2001 /// happens to be logical end. Use blocks terminator as statement that specifies
2002 /// destructors call site.
2003 /// FIXME: This mechanism for adding automatic destructors doesn't handle
2004 /// no-return destructors properly.
2005 void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
2006  LocalScope::const_iterator B, LocalScope::const_iterator E) {
2007  if (!BuildOpts.AddImplicitDtors)
2008  return;
2009  BumpVectorContext &C = cfg->getBumpVectorContext();
2010  CFGBlock::iterator InsertPos
2011  = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C);
2012  for (LocalScope::const_iterator I = B; I != E; ++I)
2013  InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I,
2014  Blk->getTerminatorStmt());
2015 }
2016 
2017 /// prependAutomaticObjLifetimeWithTerminator - Prepend lifetime CFGElements for
2018 /// variables with automatic storage duration to CFGBlock's elements vector.
2019 /// Elements will be prepended to physical beginning of the vector which
2020 /// happens to be logical end. Use blocks terminator as statement that specifies
2021 /// where lifetime ends.
2022 void CFGBuilder::prependAutomaticObjLifetimeWithTerminator(
2023  CFGBlock *Blk, LocalScope::const_iterator B, LocalScope::const_iterator E) {
2024  if (!BuildOpts.AddLifetime)
2025  return;
2026  BumpVectorContext &C = cfg->getBumpVectorContext();
2027  CFGBlock::iterator InsertPos =
2028  Blk->beginLifetimeEndsInsert(Blk->end(), B.distance(E), C);
2029  for (LocalScope::const_iterator I = B; I != E; ++I) {
2030  InsertPos =
2031  Blk->insertLifetimeEnds(InsertPos, *I, Blk->getTerminatorStmt());
2032  }
2033 }
2034 
2035 /// prependAutomaticObjScopeEndWithTerminator - Prepend scope end CFGElements for
2036 /// variables with automatic storage duration to CFGBlock's elements vector.
2037 /// Elements will be prepended to physical beginning of the vector which
2038 /// happens to be logical end. Use blocks terminator as statement that specifies
2039 /// where scope ends.
2040 const VarDecl *
2041 CFGBuilder::prependAutomaticObjScopeEndWithTerminator(
2042  CFGBlock *Blk, LocalScope::const_iterator B, LocalScope::const_iterator E) {
2043  if (!BuildOpts.AddScopes)
2044  return nullptr;
2045  BumpVectorContext &C = cfg->getBumpVectorContext();
2046  CFGBlock::iterator InsertPos =
2047  Blk->beginScopeEndInsert(Blk->end(), 1, C);
2048  LocalScope::const_iterator PlaceToInsert = B;
2049  for (LocalScope::const_iterator I = B; I != E; ++I)
2050  PlaceToInsert = I;
2051  Blk->insertScopeEnd(InsertPos, *PlaceToInsert, Blk->getTerminatorStmt());
2052  return *PlaceToInsert;
2053 }
2054 
2055 /// Visit - Walk the subtree of a statement and add extra
2056 /// blocks for ternary operators, &&, and ||. We also process "," and
2057 /// DeclStmts (which may contain nested control-flow).
2058 CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc,
2059  bool ExternallyDestructed) {
2060  if (!S) {
2061  badCFG = true;
2062  return nullptr;
2063  }
2064 
2065  if (Expr *E = dyn_cast<Expr>(S))
2066  S = E->IgnoreParens();
2067 
2068  if (Context->getLangOpts().OpenMP)
2069  if (auto *D = dyn_cast<OMPExecutableDirective>(S))
2070  return VisitOMPExecutableDirective(D, asc);
2071 
2072  switch (S->getStmtClass()) {
2073  default:
2074  return VisitStmt(S, asc);
2075 
2076  case Stmt::AddrLabelExprClass:
2077  return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc);
2078 
2079  case Stmt::BinaryConditionalOperatorClass:
2080  return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc);
2081 
2082  case Stmt::BinaryOperatorClass:
2083  return VisitBinaryOperator(cast<BinaryOperator>(S), asc);
2084 
2085  case Stmt::BlockExprClass:
2086  return VisitBlockExpr(cast<BlockExpr>(S), asc);
2087 
2088  case Stmt::BreakStmtClass:
2089  return VisitBreakStmt(cast<BreakStmt>(S));
2090 
2091  case Stmt::CallExprClass:
2092  case Stmt::CXXOperatorCallExprClass:
2093  case Stmt::CXXMemberCallExprClass:
2094  case Stmt::UserDefinedLiteralClass:
2095  return VisitCallExpr(cast<CallExpr>(S), asc);
2096 
2097  case Stmt::CaseStmtClass:
2098  return VisitCaseStmt(cast<CaseStmt>(S));
2099 
2100  case Stmt::ChooseExprClass:
2101  return VisitChooseExpr(cast<ChooseExpr>(S), asc);
2102 
2103  case Stmt::CompoundStmtClass:
2104  return VisitCompoundStmt(cast<CompoundStmt>(S), ExternallyDestructed);
2105 
2106  case Stmt::ConditionalOperatorClass:
2107  return VisitConditionalOperator(cast<ConditionalOperator>(S), asc);
2108 
2109  case Stmt::ContinueStmtClass:
2110  return VisitContinueStmt(cast<ContinueStmt>(S));
2111 
2112  case Stmt::CXXCatchStmtClass:
2113  return VisitCXXCatchStmt(cast<CXXCatchStmt>(S));
2114 
2115  case Stmt::ExprWithCleanupsClass:
2116  return VisitExprWithCleanups(cast<ExprWithCleanups>(S),
2117  asc, ExternallyDestructed);
2118 
2119  case Stmt::CXXDefaultArgExprClass:
2120  case Stmt::CXXDefaultInitExprClass:
2121  // FIXME: The expression inside a CXXDefaultArgExpr is owned by the
2122  // called function's declaration, not by the caller. If we simply add
2123  // this expression to the CFG, we could end up with the same Expr
2124  // appearing multiple times.
2125  // PR13385 / <rdar://problem/12156507>
2126  //
2127  // It's likewise possible for multiple CXXDefaultInitExprs for the same
2128  // expression to be used in the same function (through aggregate
2129  // initialization).
2130  return VisitStmt(S, asc);
2131 
2132  case Stmt::CXXBindTemporaryExprClass:
2133  return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc);
2134 
2135  case Stmt::CXXConstructExprClass:
2136  return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc);
2137 
2138  case Stmt::CXXNewExprClass:
2139  return VisitCXXNewExpr(cast<CXXNewExpr>(S), asc);
2140 
2141  case Stmt::CXXDeleteExprClass:
2142  return VisitCXXDeleteExpr(cast<CXXDeleteExpr>(S), asc);
2143 
2144  case Stmt::CXXFunctionalCastExprClass:
2145  return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc);
2146 
2147  case Stmt::CXXTemporaryObjectExprClass:
2148  return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc);
2149 
2150  case Stmt::CXXThrowExprClass:
2151  return VisitCXXThrowExpr(cast<CXXThrowExpr>(S));
2152 
2153  case Stmt::CXXTryStmtClass:
2154  return VisitCXXTryStmt(cast<CXXTryStmt>(S));
2155 
2156  case Stmt::CXXForRangeStmtClass:
2157  return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S));
2158 
2159  case Stmt::DeclStmtClass:
2160  return VisitDeclStmt(cast<DeclStmt>(S));
2161 
2162  case Stmt::DefaultStmtClass:
2163  return VisitDefaultStmt(cast<DefaultStmt>(S));
2164 
2165  case Stmt::DoStmtClass:
2166  return VisitDoStmt(cast<DoStmt>(S));
2167 
2168  case Stmt::ForStmtClass:
2169  return VisitForStmt(cast<ForStmt>(S));
2170 
2171  case Stmt::GotoStmtClass:
2172  return VisitGotoStmt(cast<GotoStmt>(S));
2173 
2174  case Stmt::GCCAsmStmtClass:
2175  return VisitGCCAsmStmt(cast<GCCAsmStmt>(S), asc);
2176 
2177  case Stmt::IfStmtClass:
2178  return VisitIfStmt(cast<IfStmt>(S));
2179 
2180  case Stmt::ImplicitCastExprClass:
2181  return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc);
2182 
2183  case Stmt::ConstantExprClass:
2184  return VisitConstantExpr(cast<ConstantExpr>(S), asc);
2185 
2186  case Stmt::IndirectGotoStmtClass:
2187  return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S));
2188 
2189  case Stmt::LabelStmtClass:
2190  return VisitLabelStmt(cast<LabelStmt>(S));
2191 
2192  case Stmt::LambdaExprClass:
2193  return VisitLambdaExpr(cast<LambdaExpr>(S), asc);
2194 
2195  case Stmt::MaterializeTemporaryExprClass:
2196  return VisitMaterializeTemporaryExpr(cast<MaterializeTemporaryExpr>(S),
2197  asc);
2198 
2199  case Stmt::MemberExprClass:
2200  return VisitMemberExpr(cast<MemberExpr>(S), asc);
2201 
2202  case Stmt::NullStmtClass:
2203  return Block;
2204 
2205  case Stmt::ObjCAtCatchStmtClass:
2206  return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S));
2207 
2208  case Stmt::ObjCAutoreleasePoolStmtClass:
2209  return VisitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(S));
2210 
2211  case Stmt::ObjCAtSynchronizedStmtClass:
2212  return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S));
2213 
2214  case Stmt::ObjCAtThrowStmtClass:
2215  return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S));
2216 
2217  case Stmt::ObjCAtTryStmtClass:
2218  return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S));
2219 
2220  case Stmt::ObjCForCollectionStmtClass:
2221  return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S));
2222 
2223  case Stmt::ObjCMessageExprClass:
2224  return VisitObjCMessageExpr(cast<ObjCMessageExpr>(S), asc);
2225 
2226  case Stmt::OpaqueValueExprClass:
2227  return Block;
2228 
2229  case Stmt::PseudoObjectExprClass:
2230  return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S));
2231 
2232  case Stmt::ReturnStmtClass:
2233  case Stmt::CoreturnStmtClass:
2234  return VisitReturnStmt(S);
2235 
2236  case Stmt::SEHExceptStmtClass:
2237  return VisitSEHExceptStmt(cast<SEHExceptStmt>(S));
2238 
2239  case Stmt::SEHFinallyStmtClass:
2240  return VisitSEHFinallyStmt(cast<SEHFinallyStmt>(S));
2241 
2242  case Stmt::SEHLeaveStmtClass:
2243  return VisitSEHLeaveStmt(cast<SEHLeaveStmt>(S));
2244 
2245  case Stmt::SEHTryStmtClass:
2246  return VisitSEHTryStmt(cast<SEHTryStmt>(S));
2247 
2248  case Stmt::UnaryExprOrTypeTraitExprClass:
2249  return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S),
2250  asc);
2251 
2252  case Stmt::StmtExprClass:
2253  return VisitStmtExpr(cast<StmtExpr>(S), asc);
2254 
2255  case Stmt::SwitchStmtClass:
2256  return VisitSwitchStmt(cast<SwitchStmt>(S));
2257 
2258  case Stmt::UnaryOperatorClass:
2259  return VisitUnaryOperator(cast<UnaryOperator>(S), asc);
2260 
2261  case Stmt::WhileStmtClass:
2262  return VisitWhileStmt(cast<WhileStmt>(S));
2263  }
2264 }
2265 
2266 CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) {
2267  if (asc.alwaysAdd(*this, S)) {
2268  autoCreateBlock();
2269  appendStmt(Block, S);
2270  }
2271 
2272  return VisitChildren(S);
2273 }
2274 
2275 /// VisitChildren - Visit the children of a Stmt.
2276 CFGBlock *CFGBuilder::VisitChildren(Stmt *S) {
2277  CFGBlock *B = Block;
2278 
2279  // Visit the children in their reverse order so that they appear in
2280  // left-to-right (natural) order in the CFG.
2281  reverse_children RChildren(S);
2282  for (reverse_children::iterator I = RChildren.begin(), E = RChildren.end();
2283  I != E; ++I) {
2284  if (Stmt *Child = *I)
2285  if (CFGBlock *R = Visit(Child))
2286  B = R;
2287  }
2288  return B;
2289 }
2290 
2291 CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A,
2292  AddStmtChoice asc) {
2293  AddressTakenLabels.insert(A->getLabel());
2294 
2295  if (asc.alwaysAdd(*this, A)) {
2296  autoCreateBlock();
2297  appendStmt(Block, A);
2298  }
2299 
2300  return Block;
2301 }
2302 
2303 CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U,
2304  AddStmtChoice asc) {
2305  if (asc.alwaysAdd(*this, U)) {
2306  autoCreateBlock();
2307  appendStmt(Block, U);
2308  }
2309 
2310  return Visit(U->getSubExpr(), AddStmtChoice());
2311 }
2312 
2313 CFGBlock *CFGBuilder::VisitLogicalOperator(BinaryOperator *B) {
2314  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2315  appendStmt(ConfluenceBlock, B);
2316 
2317  if (badCFG)
2318  return nullptr;
2319 
2320  return VisitLogicalOperator(B, nullptr, ConfluenceBlock,
2321  ConfluenceBlock).first;
2322 }
2323 
2324 std::pair<CFGBlock*, CFGBlock*>
2325 CFGBuilder::VisitLogicalOperator(BinaryOperator *B,
2326  Stmt *Term,
2327  CFGBlock *TrueBlock,
2328  CFGBlock *FalseBlock) {
2329  // Introspect the RHS. If it is a nested logical operation, we recursively
2330  // build the CFG using this function. Otherwise, resort to default
2331  // CFG construction behavior.
2332  Expr *RHS = B->getRHS()->IgnoreParens();
2333  CFGBlock *RHSBlock, *ExitBlock;
2334 
2335  do {
2336  if (BinaryOperator *B_RHS = dyn_cast<BinaryOperator>(RHS))
2337  if (B_RHS->isLogicalOp()) {
2338  std::tie(RHSBlock, ExitBlock) =
2339  VisitLogicalOperator(B_RHS, Term, TrueBlock, FalseBlock);
2340  break;
2341  }
2342 
2343  // The RHS is not a nested logical operation. Don't push the terminator
2344  // down further, but instead visit RHS and construct the respective
2345  // pieces of the CFG, and link up the RHSBlock with the terminator
2346  // we have been provided.
2347  ExitBlock = RHSBlock = createBlock(false);
2348 
2349  // Even though KnownVal is only used in the else branch of the next
2350  // conditional, tryEvaluateBool performs additional checking on the
2351  // Expr, so it should be called unconditionally.
2352  TryResult KnownVal = tryEvaluateBool(RHS);
2353  if (!KnownVal.isKnown())
2354  KnownVal = tryEvaluateBool(B);
2355 
2356  if (!Term) {
2357  assert(TrueBlock == FalseBlock);
2358  addSuccessor(RHSBlock, TrueBlock);
2359  }
2360  else {
2361  RHSBlock->setTerminator(Term);
2362  addSuccessor(RHSBlock, TrueBlock, !KnownVal.isFalse());
2363  addSuccessor(RHSBlock, FalseBlock, !KnownVal.isTrue());
2364  }
2365 
2366  Block = RHSBlock;
2367  RHSBlock = addStmt(RHS);
2368  }
2369  while (false);
2370 
2371  if (badCFG)
2372  return std::make_pair(nullptr, nullptr);
2373 
2374  // Generate the blocks for evaluating the LHS.
2375  Expr *LHS = B->getLHS()->IgnoreParens();
2376 
2377  if (BinaryOperator *B_LHS = dyn_cast<BinaryOperator>(LHS))
2378  if (B_LHS->isLogicalOp()) {
2379  if (B->getOpcode() == BO_LOr)
2380  FalseBlock = RHSBlock;
2381  else
2382  TrueBlock = RHSBlock;
2383 
2384  // For the LHS, treat 'B' as the terminator that we want to sink
2385  // into the nested branch. The RHS always gets the top-most
2386  // terminator.
2387  return VisitLogicalOperator(B_LHS, B, TrueBlock, FalseBlock);
2388  }
2389 
2390  // Create the block evaluating the LHS.
2391  // This contains the '&&' or '||' as the terminator.
2392  CFGBlock *LHSBlock = createBlock(false);
2393  LHSBlock->setTerminator(B);
2394 
2395  Block = LHSBlock;
2396  CFGBlock *EntryLHSBlock = addStmt(LHS);
2397 
2398  if (badCFG)
2399  return std::make_pair(nullptr, nullptr);
2400 
2401  // See if this is a known constant.
2402  TryResult KnownVal = tryEvaluateBool(LHS);
2403 
2404  // Now link the LHSBlock with RHSBlock.
2405  if (B->getOpcode() == BO_LOr) {
2406  addSuccessor(LHSBlock, TrueBlock, !KnownVal.isFalse());
2407  addSuccessor(LHSBlock, RHSBlock, !KnownVal.isTrue());
2408  } else {
2409  assert(B->getOpcode() == BO_LAnd);
2410  addSuccessor(LHSBlock, RHSBlock, !KnownVal.isFalse());
2411  addSuccessor(LHSBlock, FalseBlock, !KnownVal.isTrue());
2412  }
2413 
2414  return std::make_pair(EntryLHSBlock, ExitBlock);
2415 }
2416 
2417 CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B,
2418  AddStmtChoice asc) {
2419  // && or ||
2420  if (B->isLogicalOp())
2421  return VisitLogicalOperator(B);
2422 
2423  if (B->getOpcode() == BO_Comma) { // ,
2424  autoCreateBlock();
2425  appendStmt(Block, B);
2426  addStmt(B->getRHS());
2427  return addStmt(B->getLHS());
2428  }
2429 
2430  if (B->isAssignmentOp()) {
2431  if (asc.alwaysAdd(*this, B)) {
2432  autoCreateBlock();
2433  appendStmt(Block, B);
2434  }
2435  Visit(B->getLHS());
2436  return Visit(B->getRHS());
2437  }
2438 
2439  if (asc.alwaysAdd(*this, B)) {
2440  autoCreateBlock();
2441  appendStmt(Block, B);
2442  }
2443 
2444  CFGBlock *RBlock = Visit(B->getRHS());
2445  CFGBlock *LBlock = Visit(B->getLHS());
2446  // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr
2447  // containing a DoStmt, and the LHS doesn't create a new block, then we should
2448  // return RBlock. Otherwise we'll incorrectly return NULL.
2449  return (LBlock ? LBlock : RBlock);
2450 }
2451 
2452 CFGBlock *CFGBuilder::VisitNoRecurse(Expr *E, AddStmtChoice asc) {
2453  if (asc.alwaysAdd(*this, E)) {
2454  autoCreateBlock();
2455  appendStmt(Block, E);
2456  }
2457  return Block;
2458 }
2459 
2460 CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) {
2461  // "break" is a control-flow statement. Thus we stop processing the current
2462  // block.
2463  if (badCFG)
2464  return nullptr;
2465 
2466  // Now create a new block that ends with the break statement.
2467  Block = createBlock(false);
2468  Block->setTerminator(B);
2469 
2470  // If there is no target for the break, then we are looking at an incomplete
2471  // AST. This means that the CFG cannot be constructed.
2472  if (BreakJumpTarget.block) {
2473  addAutomaticObjHandling(ScopePos, BreakJumpTarget.scopePosition, B);
2474  addSuccessor(Block, BreakJumpTarget.block);
2475  } else
2476  badCFG = true;
2477 
2478  return Block;
2479 }
2480 
2481 static bool CanThrow(Expr *E, ASTContext &Ctx) {
2482  QualType Ty = E->getType();
2483  if (Ty->isFunctionPointerType() || Ty->isBlockPointerType())
2484  Ty = Ty->getPointeeType();
2485 
2486  const FunctionType *FT = Ty->getAs<FunctionType>();
2487  if (FT) {
2488  if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT))
2489  if (!isUnresolvedExceptionSpec(Proto->getExceptionSpecType()) &&
2490  Proto->isNothrow())
2491  return false;
2492  }
2493  return true;
2494 }
2495 
2496 CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) {
2497  // Compute the callee type.
2498  QualType calleeType = C->getCallee()->getType();
2499  if (calleeType == Context->BoundMemberTy) {
2500  QualType boundType = Expr::findBoundMemberType(C->getCallee());
2501 
2502  // We should only get a null bound type if processing a dependent
2503  // CFG. Recover by assuming nothing.
2504  if (!boundType.isNull()) calleeType = boundType;
2505  }
2506 
2507  // If this is a call to a no-return function, this stops the block here.
2508  bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn();
2509 
2510  bool AddEHEdge = false;
2511 
2512  // Languages without exceptions are assumed to not throw.
2513  if (Context->getLangOpts().Exceptions) {
2514  if (BuildOpts.AddEHEdges)
2515  AddEHEdge = true;
2516  }
2517 
2518  // If this is a call to a builtin function, it might not actually evaluate
2519  // its arguments. Don't add them to the CFG if this is the case.
2520  bool OmitArguments = false;
2521 
2522  if (FunctionDecl *FD = C->getDirectCallee()) {
2523  // TODO: Support construction contexts for variadic function arguments.
2524  // These are a bit problematic and not very useful because passing
2525  // C++ objects as C-style variadic arguments doesn't work in general
2526  // (see [expr.call]).
2527  if (!FD->isVariadic())
2528  findConstructionContextsForArguments(C);
2529 
2530  if (FD->isNoReturn() || C->isBuiltinAssumeFalse(*Context))
2531  NoReturn = true;
2532  if (FD->hasAttr<NoThrowAttr>())
2533  AddEHEdge = false;
2534  if (FD->getBuiltinID() == Builtin::BI__builtin_object_size ||
2535  FD->getBuiltinID() == Builtin::BI__builtin_dynamic_object_size)
2536  OmitArguments = true;
2537  }
2538 
2539  if (!CanThrow(C->getCallee(), *Context))
2540  AddEHEdge = false;
2541 
2542  if (OmitArguments) {
2543  assert(!NoReturn && "noreturn calls with unevaluated args not implemented");
2544  assert(!AddEHEdge && "EH calls with unevaluated args not implemented");
2545  autoCreateBlock();
2546  appendStmt(Block, C);
2547  return Visit(C->getCallee());
2548  }
2549 
2550  if (!NoReturn && !AddEHEdge) {
2551  autoCreateBlock();
2552  appendCall(Block, C);
2553 
2554  return VisitChildren(C);
2555  }
2556 
2557  if (Block) {
2558  Succ = Block;
2559  if (badCFG)
2560  return nullptr;
2561  }
2562 
2563  if (NoReturn)
2564  Block = createNoReturnBlock();
2565  else
2566  Block = createBlock();
2567 
2568  appendCall(Block, C);
2569 
2570  if (AddEHEdge) {
2571  // Add exceptional edges.
2572  if (TryTerminatedBlock)
2573  addSuccessor(Block, TryTerminatedBlock);
2574  else
2575  addSuccessor(Block, &cfg->getExit());
2576  }
2577 
2578  return VisitChildren(C);
2579 }
2580 
2581 CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C,
2582  AddStmtChoice asc) {
2583  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2584  appendStmt(ConfluenceBlock, C);
2585  if (badCFG)
2586  return nullptr;
2587 
2588  AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2589  Succ = ConfluenceBlock;
2590  Block = nullptr;
2591  CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd);
2592  if (badCFG)
2593  return nullptr;
2594 
2595  Succ = ConfluenceBlock;
2596  Block = nullptr;
2597  CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd);
2598  if (badCFG)
2599  return nullptr;
2600 
2601  Block = createBlock(false);
2602  // See if this is a known constant.
2603  const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2604  addSuccessor(Block, KnownVal.isFalse() ? nullptr : LHSBlock);
2605  addSuccessor(Block, KnownVal.isTrue() ? nullptr : RHSBlock);
2606  Block->setTerminator(C);
2607  return addStmt(C->getCond());
2608 }
2609 
2610 CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C, bool ExternallyDestructed) {
2611  LocalScope::const_iterator scopeBeginPos = ScopePos;
2612  addLocalScopeForStmt(C);
2613 
2614  if (!C->body_empty() && !isa<ReturnStmt>(*C->body_rbegin())) {
2615  // If the body ends with a ReturnStmt, the dtors will be added in
2616  // VisitReturnStmt.
2617  addAutomaticObjHandling(ScopePos, scopeBeginPos, C);
2618  }
2619 
2620  CFGBlock *LastBlock = Block;
2621 
2623  I != E; ++I ) {
2624  // If we hit a segment of code just containing ';' (NullStmts), we can
2625  // get a null block back. In such cases, just use the LastBlock
2626  CFGBlock *newBlock = Visit(*I, AddStmtChoice::AlwaysAdd,
2627  ExternallyDestructed);
2628 
2629  if (newBlock)
2630  LastBlock = newBlock;
2631 
2632  if (badCFG)
2633  return nullptr;
2634 
2635  ExternallyDestructed = false;
2636  }
2637 
2638  return LastBlock;
2639 }
2640 
2641 CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C,
2642  AddStmtChoice asc) {
2643  const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C);
2644  const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : nullptr);
2645 
2646  // Create the confluence block that will "merge" the results of the ternary
2647  // expression.
2648  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2649  appendStmt(ConfluenceBlock, C);
2650  if (badCFG)
2651  return nullptr;
2652 
2653  AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2654 
2655  // Create a block for the LHS expression if there is an LHS expression. A
2656  // GCC extension allows LHS to be NULL, causing the condition to be the
2657  // value that is returned instead.
2658  // e.g: x ?: y is shorthand for: x ? x : y;
2659  Succ = ConfluenceBlock;
2660  Block = nullptr;
2661  CFGBlock *LHSBlock = nullptr;
2662  const Expr *trueExpr = C->getTrueExpr();
2663  if (trueExpr != opaqueValue) {
2664  LHSBlock = Visit(C->getTrueExpr(), alwaysAdd);
2665  if (badCFG)
2666  return nullptr;
2667  Block = nullptr;
2668  }
2669  else
2670  LHSBlock = ConfluenceBlock;
2671 
2672  // Create the block for the RHS expression.
2673  Succ = ConfluenceBlock;
2674  CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd);
2675  if (badCFG)
2676  return nullptr;
2677 
2678  // If the condition is a logical '&&' or '||', build a more accurate CFG.
2679  if (BinaryOperator *Cond =
2680  dyn_cast<BinaryOperator>(C->getCond()->IgnoreParens()))
2681  if (Cond->isLogicalOp())
2682  return VisitLogicalOperator(Cond, C, LHSBlock, RHSBlock).first;
2683 
2684  // Create the block that will contain the condition.
2685  Block = createBlock(false);
2686 
2687  // See if this is a known constant.
2688  const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2689  addSuccessor(Block, LHSBlock, !KnownVal.isFalse());
2690  addSuccessor(Block, RHSBlock, !KnownVal.isTrue());
2691  Block->setTerminator(C);
2692  Expr *condExpr = C->getCond();
2693 
2694  if (opaqueValue) {
2695  // Run the condition expression if it's not trivially expressed in
2696  // terms of the opaque value (or if there is no opaque value).
2697  if (condExpr != opaqueValue)
2698  addStmt(condExpr);
2699 
2700  // Before that, run the common subexpression if there was one.
2701  // At least one of this or the above will be run.
2702  return addStmt(BCO->getCommon());
2703  }
2704 
2705  return addStmt(condExpr);
2706 }
2707 
2708 CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) {
2709  // Check if the Decl is for an __label__. If so, elide it from the
2710  // CFG entirely.
2711  if (isa<LabelDecl>(*DS->decl_begin()))
2712  return Block;
2713 
2714  // This case also handles static_asserts.
2715  if (DS->isSingleDecl())
2716  return VisitDeclSubExpr(DS);
2717 
2718  CFGBlock *B = nullptr;
2719 
2720  // Build an individual DeclStmt for each decl.
2722  E = DS->decl_rend();
2723  I != E; ++I) {
2724 
2725  // Allocate the DeclStmt using the BumpPtrAllocator. It will get
2726  // automatically freed with the CFG.
2727  DeclGroupRef DG(*I);
2728  Decl *D = *I;
2729  DeclStmt *DSNew = new (Context) DeclStmt(DG, D->getLocation(), GetEndLoc(D));
2730  cfg->addSyntheticDeclStmt(DSNew, DS);
2731 
2732  // Append the fake DeclStmt to block.
2733  B = VisitDeclSubExpr(DSNew);
2734  }
2735 
2736  return B;
2737 }
2738 
2739 /// VisitDeclSubExpr - Utility method to add block-level expressions for
2740 /// DeclStmts and initializers in them.
2741 CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) {
2742  assert(DS->isSingleDecl() && "Can handle single declarations only.");
2743  VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl());
2744 
2745  if (!VD) {
2746  // Of everything that can be declared in a DeclStmt, only VarDecls impact
2747  // runtime semantics.
2748  return Block;
2749  }
2750 
2751  bool HasTemporaries = false;
2752 
2753  // Guard static initializers under a branch.
2754  CFGBlock *blockAfterStaticInit = nullptr;
2755 
2756  if (BuildOpts.AddStaticInitBranches && VD->isStaticLocal()) {
2757  // For static variables, we need to create a branch to track
2758  // whether or not they are initialized.
2759  if (Block) {
2760  Succ = Block;
2761  Block = nullptr;
2762  if (badCFG)
2763  return nullptr;
2764  }
2765  blockAfterStaticInit = Succ;
2766  }
2767 
2768  // Destructors of temporaries in initialization expression should be called
2769  // after initialization finishes.
2770  Expr *Init = VD->getInit();
2771  if (Init) {
2772  HasTemporaries = isa<ExprWithCleanups>(Init);
2773 
2774  if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
2775  // Generate destructors for temporaries in initialization expression.
2776  TempDtorContext Context;
2777  VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
2778  /*ExternallyDestructed=*/true, Context);
2779  }
2780  }
2781 
2782  autoCreateBlock();
2783  appendStmt(Block, DS);
2784 
2785  findConstructionContexts(
2786  ConstructionContextLayer::create(cfg->getBumpVectorContext(), DS),
2787  Init);
2788 
2789  // Keep track of the last non-null block, as 'Block' can be nulled out
2790  // if the initializer expression is something like a 'while' in a
2791  // statement-expression.
2792  CFGBlock *LastBlock = Block;
2793 
2794  if (Init) {
2795  if (HasTemporaries) {
2796  // For expression with temporaries go directly to subexpression to omit
2797  // generating destructors for the second time.
2798  ExprWithCleanups *EC = cast<ExprWithCleanups>(Init);
2799  if (CFGBlock *newBlock = Visit(EC->getSubExpr()))
2800  LastBlock = newBlock;
2801  }
2802  else {
2803  if (CFGBlock *newBlock = Visit(Init))
2804  LastBlock = newBlock;
2805  }
2806  }
2807 
2808  // If the type of VD is a VLA, then we must process its size expressions.
2809  for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr());
2810  VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr())) {
2811  if (CFGBlock *newBlock = addStmt(VA->getSizeExpr()))
2812  LastBlock = newBlock;
2813  }
2814 
2815  maybeAddScopeBeginForVarDecl(Block, VD, DS);
2816 
2817  // Remove variable from local scope.
2818  if (ScopePos && VD == *ScopePos)
2819  ++ScopePos;
2820 
2821  CFGBlock *B = LastBlock;
2822  if (blockAfterStaticInit) {
2823  Succ = B;
2824  Block = createBlock(false);
2825  Block->setTerminator(DS);
2826  addSuccessor(Block, blockAfterStaticInit);
2827  addSuccessor(Block, B);
2828  B = Block;
2829  }
2830 
2831  return B;
2832 }
2833 
2834 CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) {
2835  // We may see an if statement in the middle of a basic block, or it may be the
2836  // first statement we are processing. In either case, we create a new basic
2837  // block. First, we create the blocks for the then...else statements, and
2838  // then we create the block containing the if statement. If we were in the
2839  // middle of a block, we stop processing that block. That block is then the
2840  // implicit successor for the "then" and "else" clauses.
2841 
2842  // Save local scope position because in case of condition variable ScopePos
2843  // won't be restored when traversing AST.
2844  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2845 
2846  // Create local scope for C++17 if init-stmt if one exists.
2847  if (Stmt *Init = I->getInit())
2848  addLocalScopeForStmt(Init);
2849 
2850  // Create local scope for possible condition variable.
2851  // Store scope position. Add implicit destructor.
2852  if (VarDecl *VD = I->getConditionVariable())
2853  addLocalScopeForVarDecl(VD);
2854 
2855  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), I);
2856 
2857  // The block we were processing is now finished. Make it the successor
2858  // block.
2859  if (Block) {
2860  Succ = Block;
2861  if (badCFG)
2862  return nullptr;
2863  }
2864 
2865  // Process the false branch.
2866  CFGBlock *ElseBlock = Succ;
2867 
2868  if (Stmt *Else = I->getElse()) {
2869  SaveAndRestore<CFGBlock*> sv(Succ);
2870 
2871  // NULL out Block so that the recursive call to Visit will
2872  // create a new basic block.
2873  Block = nullptr;
2874 
2875  // If branch is not a compound statement create implicit scope
2876  // and add destructors.
2877  if (!isa<CompoundStmt>(Else))
2878  addLocalScopeAndDtors(Else);
2879 
2880  ElseBlock = addStmt(Else);
2881 
2882  if (!ElseBlock) // Can occur when the Else body has all NullStmts.
2883  ElseBlock = sv.get();
2884  else if (Block) {
2885  if (badCFG)
2886  return nullptr;
2887  }
2888  }
2889 
2890  // Process the true branch.
2891  CFGBlock *ThenBlock;
2892  {
2893  Stmt *Then = I->getThen();
2894  assert(Then);
2895  SaveAndRestore<CFGBlock*> sv(Succ);
2896  Block = nullptr;
2897 
2898  // If branch is not a compound statement create implicit scope
2899  // and add destructors.
2900  if (!isa<CompoundStmt>(Then))
2901  addLocalScopeAndDtors(Then);
2902 
2903  ThenBlock = addStmt(Then);
2904 
2905  if (!ThenBlock) {
2906  // We can reach here if the "then" body has all NullStmts.
2907  // Create an empty block so we can distinguish between true and false
2908  // branches in path-sensitive analyses.
2909  ThenBlock = createBlock(false);
2910  addSuccessor(ThenBlock, sv.get());
2911  } else if (Block) {
2912  if (badCFG)
2913  return nullptr;
2914  }
2915  }
2916 
2917  // Specially handle "if (expr1 || ...)" and "if (expr1 && ...)" by
2918  // having these handle the actual control-flow jump. Note that
2919  // if we introduce a condition variable, e.g. "if (int x = exp1 || exp2)"
2920  // we resort to the old control-flow behavior. This special handling
2921  // removes infeasible paths from the control-flow graph by having the
2922  // control-flow transfer of '&&' or '||' go directly into the then/else
2923  // blocks directly.
2924  BinaryOperator *Cond =
2926  ? nullptr
2927  : dyn_cast<BinaryOperator>(I->getCond()->IgnoreParens());
2928  CFGBlock *LastBlock;
2929  if (Cond && Cond->isLogicalOp())
2930  LastBlock = VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first;
2931  else {
2932  // Now create a new block containing the if statement.
2933  Block = createBlock(false);
2934 
2935  // Set the terminator of the new block to the If statement.
2936  Block->setTerminator(I);
2937 
2938  // See if this is a known constant.
2939  const TryResult &KnownVal = tryEvaluateBool(I->getCond());
2940 
2941  // Add the successors. If we know that specific branches are
2942  // unreachable, inform addSuccessor() of that knowledge.
2943  addSuccessor(Block, ThenBlock, /* IsReachable = */ !KnownVal.isFalse());
2944  addSuccessor(Block, ElseBlock, /* IsReachable = */ !KnownVal.isTrue());
2945 
2946  // Add the condition as the last statement in the new block. This may
2947  // create new blocks as the condition may contain control-flow. Any newly
2948  // created blocks will be pointed to be "Block".
2949  LastBlock = addStmt(I->getCond());
2950 
2951  // If the IfStmt contains a condition variable, add it and its
2952  // initializer to the CFG.
2953  if (const DeclStmt* DS = I->getConditionVariableDeclStmt()) {
2954  autoCreateBlock();
2955  LastBlock = addStmt(const_cast<DeclStmt *>(DS));
2956  }
2957  }
2958 
2959  // Finally, if the IfStmt contains a C++17 init-stmt, add it to the CFG.
2960  if (Stmt *Init = I->getInit()) {
2961  autoCreateBlock();
2962  LastBlock = addStmt(Init);
2963  }
2964 
2965  return LastBlock;
2966 }
2967 
2968 CFGBlock *CFGBuilder::VisitReturnStmt(Stmt *S) {
2969  // If we were in the middle of a block we stop processing that block.
2970  //
2971  // NOTE: If a "return" or "co_return" appears in the middle of a block, this
2972  // means that the code afterwards is DEAD (unreachable). We still keep
2973  // a basic block for that code; a simple "mark-and-sweep" from the entry
2974  // block will be able to report such dead blocks.
2975  assert(isa<ReturnStmt>(S) || isa<CoreturnStmt>(S));
2976 
2977  // Create the new block.
2978  Block = createBlock(false);
2979 
2980  addAutomaticObjHandling(ScopePos, LocalScope::const_iterator(), S);
2981 
2982  if (auto *R = dyn_cast<ReturnStmt>(S))
2983  findConstructionContexts(
2984  ConstructionContextLayer::create(cfg->getBumpVectorContext(), R),
2985  R->getRetValue());
2986 
2987  // If the one of the destructors does not return, we already have the Exit
2988  // block as a successor.
2989  if (!Block->hasNoReturnElement())
2990  addSuccessor(Block, &cfg->getExit());
2991 
2992  // Add the return statement to the block.
2993  appendStmt(Block, S);
2994 
2995  // Visit children
2996  if (ReturnStmt *RS = dyn_cast<ReturnStmt>(S)) {
2997  if (Expr *O = RS->getRetValue())
2998  return Visit(O, AddStmtChoice::AlwaysAdd, /*ExternallyDestructed=*/true);
2999  return Block;
3000  } else { // co_return
3001  return VisitChildren(S);
3002  }
3003 }
3004 
3005 CFGBlock *CFGBuilder::VisitSEHExceptStmt(SEHExceptStmt *ES) {
3006  // SEHExceptStmt are treated like labels, so they are the first statement in a
3007  // block.
3008 
3009  // Save local scope position because in case of exception variable ScopePos
3010  // won't be restored when traversing AST.
3011  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3012 
3013  addStmt(ES->getBlock());
3014  CFGBlock *SEHExceptBlock = Block;
3015  if (!SEHExceptBlock)
3016  SEHExceptBlock = createBlock();
3017 
3018  appendStmt(SEHExceptBlock, ES);
3019 
3020  // Also add the SEHExceptBlock as a label, like with regular labels.
3021  SEHExceptBlock->setLabel(ES);
3022 
3023  // Bail out if the CFG is bad.
3024  if (badCFG)
3025  return nullptr;
3026 
3027  // We set Block to NULL to allow lazy creation of a new block (if necessary).
3028  Block = nullptr;
3029 
3030  return SEHExceptBlock;
3031 }
3032 
3033 CFGBlock *CFGBuilder::VisitSEHFinallyStmt(SEHFinallyStmt *FS) {
3034  return VisitCompoundStmt(FS->getBlock(), /*ExternallyDestructed=*/false);
3035 }
3036 
3037 CFGBlock *CFGBuilder::VisitSEHLeaveStmt(SEHLeaveStmt *LS) {
3038  // "__leave" is a control-flow statement. Thus we stop processing the current
3039  // block.
3040  if (badCFG)
3041  return nullptr;
3042 
3043  // Now create a new block that ends with the __leave statement.
3044  Block = createBlock(false);
3045  Block->setTerminator(LS);
3046 
3047  // If there is no target for the __leave, then we are looking at an incomplete
3048  // AST. This means that the CFG cannot be constructed.
3049  if (SEHLeaveJumpTarget.block) {
3050  addAutomaticObjHandling(ScopePos, SEHLeaveJumpTarget.scopePosition, LS);
3051  addSuccessor(Block, SEHLeaveJumpTarget.block);
3052  } else
3053  badCFG = true;
3054 
3055  return Block;
3056 }
3057 
3058 CFGBlock *CFGBuilder::VisitSEHTryStmt(SEHTryStmt *Terminator) {
3059  // "__try"/"__except"/"__finally" is a control-flow statement. Thus we stop
3060  // processing the current block.
3061  CFGBlock *SEHTrySuccessor = nullptr;
3062 
3063  if (Block) {
3064  if (badCFG)
3065  return nullptr;
3066  SEHTrySuccessor = Block;
3067  } else SEHTrySuccessor = Succ;
3068 
3069  // FIXME: Implement __finally support.
3070  if (Terminator->getFinallyHandler())
3071  return NYS();
3072 
3073  CFGBlock *PrevSEHTryTerminatedBlock = TryTerminatedBlock;
3074 
3075  // Create a new block that will contain the __try statement.
3076  CFGBlock *NewTryTerminatedBlock = createBlock(false);
3077 
3078  // Add the terminator in the __try block.
3079  NewTryTerminatedBlock->setTerminator(Terminator);
3080 
3081  if (SEHExceptStmt *Except = Terminator->getExceptHandler()) {
3082  // The code after the try is the implicit successor if there's an __except.
3083  Succ = SEHTrySuccessor;
3084  Block = nullptr;
3085  CFGBlock *ExceptBlock = VisitSEHExceptStmt(Except);
3086  if (!ExceptBlock)
3087  return nullptr;
3088  // Add this block to the list of successors for the block with the try
3089  // statement.
3090  addSuccessor(NewTryTerminatedBlock, ExceptBlock);
3091  }
3092  if (PrevSEHTryTerminatedBlock)
3093  addSuccessor(NewTryTerminatedBlock, PrevSEHTryTerminatedBlock);
3094  else
3095  addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
3096 
3097  // The code after the try is the implicit successor.
3098  Succ = SEHTrySuccessor;
3099 
3100  // Save the current "__try" context.
3101  SaveAndRestore<CFGBlock *> save_try(TryTerminatedBlock,
3102  NewTryTerminatedBlock);
3103  cfg->addTryDispatchBlock(TryTerminatedBlock);
3104 
3105  // Save the current value for the __leave target.
3106  // All __leaves should go to the code following the __try
3107  // (FIXME: or if the __try has a __finally, to the __finally.)
3108  SaveAndRestore<JumpTarget> save_break(SEHLeaveJumpTarget);
3109  SEHLeaveJumpTarget = JumpTarget(SEHTrySuccessor, ScopePos);
3110 
3111  assert(Terminator->getTryBlock() && "__try must contain a non-NULL body");
3112  Block = nullptr;
3113  return addStmt(Terminator->getTryBlock());
3114 }
3115 
3116 CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) {
3117  // Get the block of the labeled statement. Add it to our map.
3118  addStmt(L->getSubStmt());
3119  CFGBlock *LabelBlock = Block;
3120 
3121  if (!LabelBlock) // This can happen when the body is empty, i.e.
3122  LabelBlock = createBlock(); // scopes that only contains NullStmts.
3123 
3124  assert(LabelMap.find(L->getDecl()) == LabelMap.end() &&
3125  "label already in map");
3126  LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos);
3127 
3128  // Labels partition blocks, so this is the end of the basic block we were
3129  // processing (L is the block's label). Because this is label (and we have
3130  // already processed the substatement) there is no extra control-flow to worry
3131  // about.
3132  LabelBlock->setLabel(L);
3133  if (badCFG)
3134  return nullptr;
3135 
3136  // We set Block to NULL to allow lazy creation of a new block (if necessary);
3137  Block = nullptr;
3138 
3139  // This block is now the implicit successor of other blocks.
3140  Succ = LabelBlock;
3141 
3142  return LabelBlock;
3143 }
3144 
3145 CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) {
3146  CFGBlock *LastBlock = VisitNoRecurse(E, asc);
3147  for (const BlockDecl::Capture &CI : E->getBlockDecl()->captures()) {
3148  if (Expr *CopyExpr = CI.getCopyExpr()) {
3149  CFGBlock *Tmp = Visit(CopyExpr);
3150  if (Tmp)
3151  LastBlock = Tmp;
3152  }
3153  }
3154  return LastBlock;
3155 }
3156 
3157 CFGBlock *CFGBuilder::VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc) {
3158  CFGBlock *LastBlock = VisitNoRecurse(E, asc);
3160  et = E->capture_init_end(); it != et; ++it) {
3161  if (Expr *Init = *it) {
3162  CFGBlock *Tmp = Visit(Init);
3163  if (Tmp)
3164  LastBlock = Tmp;
3165  }
3166  }
3167  return LastBlock;
3168 }
3169 
3170 CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) {
3171  // Goto is a control-flow statement. Thus we stop processing the current
3172  // block and create a new one.
3173 
3174  Block = createBlock(false);
3175  Block->setTerminator(G);
3176 
3177  // If we already know the mapping to the label block add the successor now.
3178  LabelMapTy::iterator I = LabelMap.find(G->getLabel());
3179 
3180  if (I == LabelMap.end())
3181  // We will need to backpatch this block later.
3182  BackpatchBlocks.push_back(JumpSource(Block, ScopePos));
3183  else {
3184  JumpTarget JT = I->second;
3185  addAutomaticObjHandling(ScopePos, JT.scopePosition, G);
3186  addSuccessor(Block, JT.block);
3187  }
3188 
3189  return Block;
3190 }
3191 
3192 CFGBlock *CFGBuilder::VisitGCCAsmStmt(GCCAsmStmt *G, AddStmtChoice asc) {
3193  // Goto is a control-flow statement. Thus we stop processing the current
3194  // block and create a new one.
3195 
3196  if (!G->isAsmGoto())
3197  return VisitStmt(G, asc);
3198 
3199  if (Block) {
3200  Succ = Block;
3201  if (badCFG)
3202  return nullptr;
3203  }
3204  Block = createBlock();
3205  Block->setTerminator(G);
3206  // We will backpatch this block later for all the labels.
3207  BackpatchBlocks.push_back(JumpSource(Block, ScopePos));
3208  // Save "Succ" in BackpatchBlocks. In the backpatch processing, "Succ" is
3209  // used to avoid adding "Succ" again.
3210  BackpatchBlocks.push_back(JumpSource(Succ, ScopePos));
3211  return Block;
3212 }
3213 
3214 CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) {
3215  CFGBlock *LoopSuccessor = nullptr;
3216 
3217  // Save local scope position because in case of condition variable ScopePos
3218  // won't be restored when traversing AST.
3219  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3220 
3221  // Create local scope for init statement and possible condition variable.
3222  // Add destructor for init statement and condition variable.
3223  // Store scope position for continue statement.
3224  if (Stmt *Init = F->getInit())
3225  addLocalScopeForStmt(Init);
3226  LocalScope::const_iterator LoopBeginScopePos = ScopePos;
3227 
3228  if (VarDecl *VD = F->getConditionVariable())
3229  addLocalScopeForVarDecl(VD);
3230  LocalScope::const_iterator ContinueScopePos = ScopePos;
3231 
3232  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), F);
3233 
3234  addLoopExit(F);
3235 
3236  // "for" is a control-flow statement. Thus we stop processing the current
3237  // block.
3238  if (Block) {
3239  if (badCFG)
3240  return nullptr;
3241  LoopSuccessor = Block;
3242  } else
3243  LoopSuccessor = Succ;
3244 
3245  // Save the current value for the break targets.
3246  // All breaks should go to the code following the loop.
3247  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3248  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3249 
3250  CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
3251 
3252  // Now create the loop body.
3253  {
3254  assert(F->getBody());
3255 
3256  // Save the current values for Block, Succ, continue and break targets.
3257  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3258  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
3259 
3260  // Create an empty block to represent the transition block for looping back
3261  // to the head of the loop. If we have increment code, it will
3262  // go in this block as well.
3263  Block = Succ = TransitionBlock = createBlock(false);
3264  TransitionBlock->setLoopTarget(F);
3265 
3266  if (Stmt *I = F->getInc()) {
3267  // Generate increment code in its own basic block. This is the target of
3268  // continue statements.
3269  Succ = addStmt(I);
3270  }
3271 
3272  // Finish up the increment (or empty) block if it hasn't been already.
3273  if (Block) {
3274  assert(Block == Succ);
3275  if (badCFG)
3276  return nullptr;
3277  Block = nullptr;
3278  }
3279 
3280  // The starting block for the loop increment is the block that should
3281  // represent the 'loop target' for looping back to the start of the loop.
3282  ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
3283  ContinueJumpTarget.block->setLoopTarget(F);
3284 
3285  // Loop body should end with destructor of Condition variable (if any).
3286  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, F);
3287 
3288  // If body is not a compound statement create implicit scope
3289  // and add destructors.
3290  if (!isa<CompoundStmt>(F->getBody()))
3291  addLocalScopeAndDtors(F->getBody());
3292 
3293  // Now populate the body block, and in the process create new blocks as we
3294  // walk the body of the loop.
3295  BodyBlock = addStmt(F->getBody());
3296 
3297  if (!BodyBlock) {
3298  // In the case of "for (...;...;...);" we can have a null BodyBlock.
3299  // Use the continue jump target as the proxy for the body.
3300  BodyBlock = ContinueJumpTarget.block;
3301  }
3302  else if (badCFG)
3303  return nullptr;
3304  }
3305 
3306  // Because of short-circuit evaluation, the condition of the loop can span
3307  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3308  // evaluate the condition.
3309  CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
3310 
3311  do {
3312  Expr *C = F->getCond();
3313  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3314 
3315  // Specially handle logical operators, which have a slightly
3316  // more optimal CFG representation.
3317  if (BinaryOperator *Cond =
3318  dyn_cast_or_null<BinaryOperator>(C ? C->IgnoreParens() : nullptr))
3319  if (Cond->isLogicalOp()) {
3320  std::tie(EntryConditionBlock, ExitConditionBlock) =
3321  VisitLogicalOperator(Cond, F, BodyBlock, LoopSuccessor);
3322  break;
3323  }
3324 
3325  // The default case when not handling logical operators.
3326  EntryConditionBlock = ExitConditionBlock = createBlock(false);
3327  ExitConditionBlock->setTerminator(F);
3328 
3329  // See if this is a known constant.
3330  TryResult KnownVal(true);
3331 
3332  if (C) {
3333  // Now add the actual condition to the condition block.
3334  // Because the condition itself may contain control-flow, new blocks may
3335  // be created. Thus we update "Succ" after adding the condition.
3336  Block = ExitConditionBlock;
3337  EntryConditionBlock = addStmt(C);
3338 
3339  // If this block contains a condition variable, add both the condition
3340  // variable and initializer to the CFG.
3341  if (VarDecl *VD = F->getConditionVariable()) {
3342  if (Expr *Init = VD->getInit()) {
3343  autoCreateBlock();
3344  const DeclStmt *DS = F->getConditionVariableDeclStmt();
3345  assert(DS->isSingleDecl());
3346  findConstructionContexts(
3347  ConstructionContextLayer::create(cfg->getBumpVectorContext(), DS),
3348  Init);
3349  appendStmt(Block, DS);
3350  EntryConditionBlock = addStmt(Init);
3351  assert(Block == EntryConditionBlock);
3352  maybeAddScopeBeginForVarDecl(EntryConditionBlock, VD, C);
3353  }
3354  }
3355 
3356  if (Block && badCFG)
3357  return nullptr;
3358 
3359  KnownVal = tryEvaluateBool(C);
3360  }
3361 
3362  // Add the loop body entry as a successor to the condition.
3363  addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
3364  // Link up the condition block with the code that follows the loop. (the
3365  // false branch).
3366  addSuccessor(ExitConditionBlock,
3367  KnownVal.isTrue() ? nullptr : LoopSuccessor);
3368  } while (false);
3369 
3370  // Link up the loop-back block to the entry condition block.
3371  addSuccessor(TransitionBlock, EntryConditionBlock);
3372 
3373  // The condition block is the implicit successor for any code above the loop.
3374  Succ = EntryConditionBlock;
3375 
3376  // If the loop contains initialization, create a new block for those
3377  // statements. This block can also contain statements that precede the loop.
3378  if (Stmt *I = F->getInit()) {
3379  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3380  ScopePos = LoopBeginScopePos;
3381  Block = createBlock();
3382  return addStmt(I);
3383  }
3384 
3385  // There is no loop initialization. We are thus basically a while loop.
3386  // NULL out Block to force lazy block construction.
3387  Block = nullptr;
3388  Succ = EntryConditionBlock;
3389  return EntryConditionBlock;
3390 }
3391 
3392 CFGBlock *
3393 CFGBuilder::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *MTE,
3394  AddStmtChoice asc) {
3395  findConstructionContexts(
3396  ConstructionContextLayer::create(cfg->getBumpVectorContext(), MTE),
3397  MTE->getTemporary());
3398 
3399  return VisitStmt(MTE, asc);
3400 }
3401 
3402 CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) {
3403  if (asc.alwaysAdd(*this, M)) {
3404  autoCreateBlock();
3405  appendStmt(Block, M);
3406  }
3407  return Visit(M->getBase());
3408 }
3409 
3410 CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) {
3411  // Objective-C fast enumeration 'for' statements:
3412  // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC
3413  //
3414  // for ( Type newVariable in collection_expression ) { statements }
3415  //
3416  // becomes:
3417  //
3418  // prologue:
3419  // 1. collection_expression
3420  // T. jump to loop_entry
3421  // loop_entry:
3422  // 1. side-effects of element expression
3423  // 1. ObjCForCollectionStmt [performs binding to newVariable]
3424  // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil]
3425  // TB:
3426  // statements
3427  // T. jump to loop_entry
3428  // FB:
3429  // what comes after
3430  //
3431  // and
3432  //
3433  // Type existingItem;
3434  // for ( existingItem in expression ) { statements }
3435  //
3436  // becomes:
3437  //
3438  // the same with newVariable replaced with existingItem; the binding works
3439  // the same except that for one ObjCForCollectionStmt::getElement() returns
3440  // a DeclStmt and the other returns a DeclRefExpr.
3441 
3442  CFGBlock *LoopSuccessor = nullptr;
3443 
3444  if (Block) {
3445  if (badCFG)
3446  return nullptr;
3447  LoopSuccessor = Block;
3448  Block = nullptr;
3449  } else
3450  LoopSuccessor = Succ;
3451 
3452  // Build the condition blocks.
3453  CFGBlock *ExitConditionBlock = createBlock(false);
3454 
3455  // Set the terminator for the "exit" condition block.
3456  ExitConditionBlock->setTerminator(S);
3457 
3458  // The last statement in the block should be the ObjCForCollectionStmt, which
3459  // performs the actual binding to 'element' and determines if there are any
3460  // more items in the collection.
3461  appendStmt(ExitConditionBlock, S);
3462  Block = ExitConditionBlock;
3463 
3464  // Walk the 'element' expression to see if there are any side-effects. We
3465  // generate new blocks as necessary. We DON'T add the statement by default to
3466  // the CFG unless it contains control-flow.
3467  CFGBlock *EntryConditionBlock = Visit(S->getElement(),
3468  AddStmtChoice::NotAlwaysAdd);
3469  if (Block) {
3470  if (badCFG)
3471  return nullptr;
3472  Block = nullptr;
3473  }
3474 
3475  // The condition block is the implicit successor for the loop body as well as
3476  // any code above the loop.
3477  Succ = EntryConditionBlock;
3478 
3479  // Now create the true branch.
3480  {
3481  // Save the current values for Succ, continue and break targets.
3482  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3483  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3484  save_break(BreakJumpTarget);
3485 
3486  // Add an intermediate block between the BodyBlock and the
3487  // EntryConditionBlock to represent the "loop back" transition, for looping
3488  // back to the head of the loop.
3489  CFGBlock *LoopBackBlock = nullptr;
3490  Succ = LoopBackBlock = createBlock();
3491  LoopBackBlock->setLoopTarget(S);
3492 
3493  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3494  ContinueJumpTarget = JumpTarget(Succ, ScopePos);
3495 
3496  CFGBlock *BodyBlock = addStmt(S->getBody());
3497 
3498  if (!BodyBlock)
3499  BodyBlock = ContinueJumpTarget.block; // can happen for "for (X in Y) ;"
3500  else if (Block) {
3501  if (badCFG)
3502  return nullptr;
3503  }
3504 
3505  // This new body block is a successor to our "exit" condition block.
3506  addSuccessor(ExitConditionBlock, BodyBlock);
3507  }
3508 
3509  // Link up the condition block with the code that follows the loop.
3510  // (the false branch).
3511  addSuccessor(ExitConditionBlock, LoopSuccessor);
3512 
3513  // Now create a prologue block to contain the collection expression.
3514  Block = createBlock();
3515  return addStmt(S->getCollection());
3516 }
3517 
3518 CFGBlock *CFGBuilder::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) {
3519  // Inline the body.
3520  return addStmt(S->getSubStmt());
3521  // TODO: consider adding cleanups for the end of @autoreleasepool scope.
3522 }
3523 
3524 CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) {
3525  // FIXME: Add locking 'primitives' to CFG for @synchronized.
3526 
3527  // Inline the body.
3528  CFGBlock *SyncBlock = addStmt(S->getSynchBody());
3529 
3530  // The sync body starts its own basic block. This makes it a little easier
3531  // for diagnostic clients.
3532  if (SyncBlock) {
3533  if (badCFG)
3534  return nullptr;
3535 
3536  Block = nullptr;
3537  Succ = SyncBlock;
3538  }
3539 
3540  // Add the @synchronized to the CFG.
3541  autoCreateBlock();
3542  appendStmt(Block, S);
3543 
3544  // Inline the sync expression.
3545  return addStmt(S->getSynchExpr());
3546 }
3547 
3548 CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) {
3549  // FIXME
3550  return NYS();
3551 }
3552 
3553 CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) {
3554  autoCreateBlock();
3555 
3556  // Add the PseudoObject as the last thing.
3557  appendStmt(Block, E);
3558 
3559  CFGBlock *lastBlock = Block;
3560 
3561  // Before that, evaluate all of the semantics in order. In
3562  // CFG-land, that means appending them in reverse order.
3563  for (unsigned i = E->getNumSemanticExprs(); i != 0; ) {
3564  Expr *Semantic = E->getSemanticExpr(--i);
3565 
3566  // If the semantic is an opaque value, we're being asked to bind
3567  // it to its source expression.
3568  if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
3569  Semantic = OVE->getSourceExpr();
3570 
3571  if (CFGBlock *B = Visit(Semantic))
3572  lastBlock = B;
3573  }
3574 
3575  return lastBlock;
3576 }
3577 
3578 CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) {
3579  CFGBlock *LoopSuccessor = nullptr;
3580 
3581  // Save local scope position because in case of condition variable ScopePos
3582  // won't be restored when traversing AST.
3583  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3584 
3585  // Create local scope for possible condition variable.
3586  // Store scope position for continue statement.
3587  LocalScope::const_iterator LoopBeginScopePos = ScopePos;
3588  if (VarDecl *VD = W->getConditionVariable()) {
3589  addLocalScopeForVarDecl(VD);
3590  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3591  }
3592  addLoopExit(W);
3593 
3594  // "while" is a control-flow statement. Thus we stop processing the current
3595  // block.
3596  if (Block) {
3597  if (badCFG)
3598  return nullptr;
3599  LoopSuccessor = Block;
3600  Block = nullptr;
3601  } else {
3602  LoopSuccessor = Succ;
3603  }
3604 
3605  CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
3606 
3607  // Process the loop body.
3608  {
3609  assert(W->getBody());
3610 
3611  // Save the current values for Block, Succ, continue and break targets.
3612  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3613  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3614  save_break(BreakJumpTarget);
3615 
3616  // Create an empty block to represent the transition block for looping back
3617  // to the head of the loop.
3618  Succ = TransitionBlock = createBlock(false);
3619  TransitionBlock->setLoopTarget(W);
3620  ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos);
3621 
3622  // All breaks should go to the code following the loop.
3623  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3624 
3625  // Loop body should end with destructor of Condition variable (if any).
3626  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3627 
3628  // If body is not a compound statement create implicit scope
3629  // and add destructors.
3630  if (!isa<CompoundStmt>(W->getBody()))
3631  addLocalScopeAndDtors(W->getBody());
3632 
3633  // Create the body. The returned block is the entry to the loop body.
3634  BodyBlock = addStmt(W->getBody());
3635 
3636  if (!BodyBlock)
3637  BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;"
3638  else if (Block && badCFG)
3639  return nullptr;
3640  }
3641 
3642  // Because of short-circuit evaluation, the condition of the loop can span
3643  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3644  // evaluate the condition.
3645  CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
3646 
3647  do {
3648  Expr *C = W->getCond();
3649 
3650  // Specially handle logical operators, which have a slightly
3651  // more optimal CFG representation.
3652  if (BinaryOperator *Cond = dyn_cast<BinaryOperator>(C->IgnoreParens()))
3653  if (Cond->isLogicalOp()) {
3654  std::tie(EntryConditionBlock, ExitConditionBlock) =
3655  VisitLogicalOperator(Cond, W, BodyBlock, LoopSuccessor);
3656  break;
3657  }
3658 
3659  // The default case when not handling logical operators.
3660  ExitConditionBlock = createBlock(false);
3661  ExitConditionBlock->setTerminator(W);
3662 
3663  // Now add the actual condition to the condition block.
3664  // Because the condition itself may contain control-flow, new blocks may
3665  // be created. Thus we update "Succ" after adding the condition.
3666  Block = ExitConditionBlock;
3667  Block = EntryConditionBlock = addStmt(C);
3668 
3669  // If this block contains a condition variable, add both the condition
3670  // variable and initializer to the CFG.
3671  if (VarDecl *VD = W->getConditionVariable()) {
3672  if (Expr *Init = VD->getInit()) {
3673  autoCreateBlock();
3674  const DeclStmt *DS = W->getConditionVariableDeclStmt();
3675  assert(DS->isSingleDecl());
3676  findConstructionContexts(
3677  ConstructionContextLayer::create(cfg->getBumpVectorContext(),
3678  const_cast<DeclStmt *>(DS)),
3679  Init);
3680  appendStmt(Block, DS);
3681  EntryConditionBlock = addStmt(Init);
3682  assert(Block == EntryConditionBlock);
3683  maybeAddScopeBeginForVarDecl(EntryConditionBlock, VD, C);
3684  }
3685  }
3686 
3687  if (Block && badCFG)
3688  return nullptr;
3689 
3690  // See if this is a known constant.
3691  const TryResult& KnownVal = tryEvaluateBool(C);
3692 
3693  // Add the loop body entry as a successor to the condition.
3694  addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
3695  // Link up the condition block with the code that follows the loop. (the
3696  // false branch).
3697  addSuccessor(ExitConditionBlock,
3698  KnownVal.isTrue() ? nullptr : LoopSuccessor);
3699  } while(false);
3700 
3701  // Link up the loop-back block to the entry condition block.
3702  addSuccessor(TransitionBlock, EntryConditionBlock);
3703 
3704  // There can be no more statements in the condition block since we loop back
3705  // to this block. NULL out Block to force lazy creation of another block.
3706  Block = nullptr;
3707 
3708  // Return the condition block, which is the dominating block for the loop.
3709  Succ = EntryConditionBlock;
3710  return EntryConditionBlock;
3711 }
3712 
3713 CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) {
3714  // FIXME: For now we pretend that @catch and the code it contains does not
3715  // exit.
3716  return Block;
3717 }
3718 
3719 CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) {
3720  // FIXME: This isn't complete. We basically treat @throw like a return
3721  // statement.
3722 
3723  // If we were in the middle of a block we stop processing that block.
3724  if (badCFG)
3725  return nullptr;
3726 
3727  // Create the new block.
3728  Block = createBlock(false);
3729 
3730  // The Exit block is the only successor.
3731  addSuccessor(Block, &cfg->getExit());
3732 
3733  // Add the statement to the block. This may create new blocks if S contains
3734  // control-flow (short-circuit operations).
3735  return VisitStmt(S, AddStmtChoice::AlwaysAdd);
3736 }
3737 
3738 CFGBlock *CFGBuilder::VisitObjCMessageExpr(ObjCMessageExpr *ME,
3739  AddStmtChoice asc) {
3740  findConstructionContextsForArguments(ME);
3741 
3742  autoCreateBlock();
3743  appendObjCMessage(Block, ME);
3744 
3745  return VisitChildren(ME);
3746 }
3747 
3748 CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) {
3749  // If we were in the middle of a block we stop processing that block.
3750  if (badCFG)
3751  return nullptr;
3752 
3753  // Create the new block.
3754  Block = createBlock(false);
3755 
3756  if (TryTerminatedBlock)
3757  // The current try statement is the only successor.
3758  addSuccessor(Block, TryTerminatedBlock);
3759  else
3760  // otherwise the Exit block is the only successor.
3761  addSuccessor(Block, &cfg->getExit());
3762 
3763  // Add the statement to the block. This may create new blocks if S contains
3764  // control-flow (short-circuit operations).
3765  return VisitStmt(T, AddStmtChoice::AlwaysAdd);
3766 }
3767 
3768 CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) {
3769  CFGBlock *LoopSuccessor = nullptr;
3770 
3771  addLoopExit(D);
3772 
3773  // "do...while" is a control-flow statement. Thus we stop processing the
3774  // current block.
3775  if (Block) {
3776  if (badCFG)
3777  return nullptr;
3778  LoopSuccessor = Block;
3779  } else
3780  LoopSuccessor = Succ;
3781 
3782  // Because of short-circuit evaluation, the condition of the loop can span
3783  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3784  // evaluate the condition.
3785  CFGBlock *ExitConditionBlock = createBlock(false);
3786  CFGBlock *EntryConditionBlock = ExitConditionBlock;
3787 
3788  // Set the terminator for the "exit" condition block.
3789  ExitConditionBlock->setTerminator(D);
3790 
3791  // Now add the actual condition to the condition block. Because the condition
3792  // itself may contain control-flow, new blocks may be created.
3793  if (Stmt *C = D->getCond()) {
3794  Block = ExitConditionBlock;
3795  EntryConditionBlock = addStmt(C);
3796  if (Block) {
3797  if (badCFG)
3798  return nullptr;
3799  }
3800  }
3801 
3802  // The condition block is the implicit successor for the loop body.
3803  Succ = EntryConditionBlock;
3804 
3805  // See if this is a known constant.
3806  const TryResult &KnownVal = tryEvaluateBool(D->getCond());
3807 
3808  // Process the loop body.
3809  CFGBlock *BodyBlock = nullptr;
3810  {
3811  assert(D->getBody());
3812 
3813  // Save the current values for Block, Succ, and continue and break targets
3814  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3815  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3816  save_break(BreakJumpTarget);
3817 
3818  // All continues within this loop should go to the condition block
3819  ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos);
3820 
3821  // All breaks should go to the code following the loop.
3822  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3823 
3824  // NULL out Block to force lazy instantiation of blocks for the body.
3825  Block = nullptr;
3826 
3827  // If body is not a compound statement create implicit scope
3828  // and add destructors.
3829  if (!isa<CompoundStmt>(D->getBody()))
3830  addLocalScopeAndDtors(D->getBody());
3831 
3832  // Create the body. The returned block is the entry to the loop body.
3833  BodyBlock = addStmt(D->getBody());
3834 
3835  if (!BodyBlock)
3836  BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)"
3837  else if (Block) {
3838  if (badCFG)
3839  return nullptr;
3840  }
3841 
3842  // Add an intermediate block between the BodyBlock and the
3843  // ExitConditionBlock to represent the "loop back" transition. Create an
3844  // empty block to represent the transition block for looping back to the
3845  // head of the loop.
3846  // FIXME: Can we do this more efficiently without adding another block?
3847  Block = nullptr;
3848  Succ = BodyBlock;
3849  CFGBlock *LoopBackBlock = createBlock();
3850  LoopBackBlock->setLoopTarget(D);
3851 
3852  if (!KnownVal.isFalse())
3853  // Add the loop body entry as a successor to the condition.
3854  addSuccessor(ExitConditionBlock, LoopBackBlock);
3855  else
3856  addSuccessor(ExitConditionBlock, nullptr);
3857  }
3858 
3859  // Link up the condition block with the code that follows the loop.
3860  // (the false branch).
3861  addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
3862 
3863  // There can be no more statements in the body block(s) since we loop back to
3864  // the body. NULL out Block to force lazy creation of another block.
3865  Block = nullptr;
3866 
3867  // Return the loop body, which is the dominating block for the loop.
3868  Succ = BodyBlock;
3869  return BodyBlock;
3870 }
3871 
3872 CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) {
3873  // "continue" is a control-flow statement. Thus we stop processing the
3874  // current block.
3875  if (badCFG)
3876  return nullptr;
3877 
3878  // Now create a new block that ends with the continue statement.
3879  Block = createBlock(false);
3880  Block->setTerminator(C);
3881 
3882  // If there is no target for the continue, then we are looking at an
3883  // incomplete AST. This means the CFG cannot be constructed.
3884  if (ContinueJumpTarget.block) {
3885  addAutomaticObjHandling(ScopePos, ContinueJumpTarget.scopePosition, C);
3886  addSuccessor(Block, ContinueJumpTarget.block);
3887  } else
3888  badCFG = true;
3889 
3890  return Block;
3891 }
3892 
3893 CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
3894  AddStmtChoice asc) {
3895  if (asc.alwaysAdd(*this, E)) {
3896  autoCreateBlock();
3897  appendStmt(Block, E);
3898  }
3899 
3900  // VLA types have expressions that must be evaluated.
3901  CFGBlock *lastBlock = Block;
3902 
3903  if (E->isArgumentType()) {
3904  for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr());
3905  VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr()))
3906  lastBlock = addStmt(VA->getSizeExpr());
3907  }
3908  return lastBlock;
3909 }
3910 
3911 /// VisitStmtExpr - Utility method to handle (nested) statement
3912 /// expressions (a GCC extension).
3913 CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) {
3914  if (asc.alwaysAdd(*this, SE)) {
3915  autoCreateBlock();
3916  appendStmt(Block, SE);
3917  }
3918  return VisitCompoundStmt(SE->getSubStmt(), /*ExternallyDestructed=*/true);
3919 }
3920 
3921 CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) {
3922  // "switch" is a control-flow statement. Thus we stop processing the current
3923  // block.
3924  CFGBlock *SwitchSuccessor = nullptr;
3925 
3926  // Save local scope position because in case of condition variable ScopePos
3927  // won't be restored when traversing AST.
3928  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3929 
3930  // Create local scope for C++17 switch init-stmt if one exists.
3931  if (Stmt *Init = Terminator->getInit())
3932  addLocalScopeForStmt(Init);
3933 
3934  // Create local scope for possible condition variable.
3935  // Store scope position. Add implicit destructor.
3936  if (VarDecl *VD = Terminator->getConditionVariable())
3937  addLocalScopeForVarDecl(VD);
3938 
3939  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), Terminator);
3940 
3941  if (Block) {
3942  if (badCFG)
3943  return nullptr;
3944  SwitchSuccessor = Block;
3945  } else SwitchSuccessor = Succ;
3946 
3947  // Save the current "switch" context.
3948  SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock),
3949  save_default(DefaultCaseBlock);
3950  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3951 
3952  // Set the "default" case to be the block after the switch statement. If the
3953  // switch statement contains a "default:", this value will be overwritten with
3954  // the block for that code.
3955  DefaultCaseBlock = SwitchSuccessor;
3956 
3957  // Create a new block that will contain the switch statement.
3958  SwitchTerminatedBlock = createBlock(false);
3959 
3960  // Now process the switch body. The code after the switch is the implicit
3961  // successor.
3962  Succ = SwitchSuccessor;
3963  BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos);
3964 
3965  // When visiting the body, the case statements should automatically get linked
3966  // up to the switch. We also don't keep a pointer to the body, since all
3967  // control-flow from the switch goes to case/default statements.
3968  assert(Terminator->getBody() && "switch must contain a non-NULL body");
3969  Block = nullptr;
3970 
3971  // For pruning unreachable case statements, save the current state
3972  // for tracking the condition value.
3973  SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered,
3974  false);
3975 
3976  // Determine if the switch condition can be explicitly evaluated.
3977  assert(Terminator->getCond() && "switch condition must be non-NULL");
3978  Expr::EvalResult result;
3979  bool b = tryEvaluate(Terminator->getCond(), result);
3980  SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond,
3981  b ? &result : nullptr);
3982 
3983  // If body is not a compound statement create implicit scope
3984  // and add destructors.
3985  if (!isa<CompoundStmt>(Terminator->getBody()))
3986  addLocalScopeAndDtors(Terminator->getBody());
3987 
3988  addStmt(Terminator->getBody());
3989  if (Block) {
3990  if (badCFG)
3991  return nullptr;
3992  }
3993 
3994  // If we have no "default:" case, the default transition is to the code
3995  // following the switch body. Moreover, take into account if all the
3996  // cases of a switch are covered (e.g., switching on an enum value).
3997  //
3998  // Note: We add a successor to a switch that is considered covered yet has no
3999  // case statements if the enumeration has no enumerators.
4000  bool SwitchAlwaysHasSuccessor = false;
4001  SwitchAlwaysHasSuccessor |= switchExclusivelyCovered;
4002  SwitchAlwaysHasSuccessor |= Terminator->isAllEnumCasesCovered() &&
4003  Terminator->getSwitchCaseList();
4004  addSuccessor(SwitchTerminatedBlock, DefaultCaseBlock,
4005  !SwitchAlwaysHasSuccessor);
4006 
4007  // Add the terminator and condition in the switch block.
4008  SwitchTerminatedBlock->setTerminator(Terminator);
4009  Block = SwitchTerminatedBlock;
4010  CFGBlock *LastBlock = addStmt(Terminator->getCond());
4011 
4012  // If the SwitchStmt contains a condition variable, add both the
4013  // SwitchStmt and the condition variable initialization to the CFG.
4014  if (VarDecl *VD = Terminator->getConditionVariable()) {
4015  if (Expr *Init = VD->getInit()) {
4016  autoCreateBlock();
4017  appendStmt(Block, Terminator->getConditionVariableDeclStmt());
4018  LastBlock = addStmt(Init);
4019  maybeAddScopeBeginForVarDecl(LastBlock, VD, Init);
4020  }
4021  }
4022 
4023  // Finally, if the SwitchStmt contains a C++17 init-stmt, add it to the CFG.
4024  if (Stmt *Init = Terminator->getInit()) {
4025  autoCreateBlock();
4026  LastBlock = addStmt(Init);
4027  }
4028 
4029  return LastBlock;
4030 }
4031 
4032 static bool shouldAddCase(bool &switchExclusivelyCovered,
4033  const Expr::EvalResult *switchCond,
4034  const CaseStmt *CS,
4035  ASTContext &Ctx) {
4036  if (!switchCond)
4037  return true;
4038 
4039  bool addCase = false;
4040 
4041  if (!switchExclusivelyCovered) {
4042  if (switchCond->Val.isInt()) {
4043  // Evaluate the LHS of the case value.
4044  const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx);
4045  const llvm::APSInt &condInt = switchCond->Val.getInt();
4046 
4047  if (condInt == lhsInt) {
4048  addCase = true;
4049  switchExclusivelyCovered = true;
4050  }
4051  else if (condInt > lhsInt) {
4052  if (const Expr *RHS = CS->getRHS()) {
4053  // Evaluate the RHS of the case value.
4054  const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx);
4055  if (V2 >= condInt) {
4056  addCase = true;
4057  switchExclusivelyCovered = true;
4058  }
4059  }
4060  }
4061  }
4062  else
4063  addCase = true;
4064  }
4065  return addCase;
4066 }
4067 
4068 CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) {
4069  // CaseStmts are essentially labels, so they are the first statement in a
4070  // block.
4071  CFGBlock *TopBlock = nullptr, *LastBlock = nullptr;
4072 
4073  if (Stmt *Sub = CS->getSubStmt()) {
4074  // For deeply nested chains of CaseStmts, instead of doing a recursion
4075  // (which can blow out the stack), manually unroll and create blocks
4076  // along the way.
4077  while (isa<CaseStmt>(Sub)) {
4078  CFGBlock *currentBlock = createBlock(false);
4079  currentBlock->setLabel(CS);
4080 
4081  if (TopBlock)
4082  addSuccessor(LastBlock, currentBlock);
4083  else
4084  TopBlock = currentBlock;
4085 
4086  addSuccessor(SwitchTerminatedBlock,
4087  shouldAddCase(switchExclusivelyCovered, switchCond,
4088  CS, *Context)
4089  ? currentBlock : nullptr);
4090 
4091  LastBlock = currentBlock;
4092  CS = cast<CaseStmt>(Sub);
4093  Sub = CS->getSubStmt();
4094  }
4095 
4096  addStmt(Sub);
4097  }
4098 
4099  CFGBlock *CaseBlock = Block;
4100  if (!CaseBlock)
4101  CaseBlock = createBlock();
4102 
4103  // Cases statements partition blocks, so this is the top of the basic block we
4104  // were processing (the "case XXX:" is the label).
4105  CaseBlock->setLabel(CS);
4106 
4107  if (badCFG)
4108  return nullptr;
4109 
4110  // Add this block to the list of successors for the block with the switch
4111  // statement.
4112  assert(SwitchTerminatedBlock);
4113  addSuccessor(SwitchTerminatedBlock, CaseBlock,
4114  shouldAddCase(switchExclusivelyCovered, switchCond,
4115  CS, *Context));
4116 
4117  // We set Block to NULL to allow lazy creation of a new block (if necessary)
4118  Block = nullptr;
4119 
4120  if (TopBlock) {
4121  addSuccessor(LastBlock, CaseBlock);
4122  Succ = TopBlock;
4123  } else {
4124  // This block is now the implicit successor of other blocks.
4125  Succ = CaseBlock;
4126  }
4127 
4128  return Succ;
4129 }
4130 
4131 CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) {
4132  if (Terminator->getSubStmt())
4133  addStmt(Terminator->getSubStmt());
4134 
4135  DefaultCaseBlock = Block;
4136 
4137  if (!DefaultCaseBlock)
4138  DefaultCaseBlock = createBlock();
4139 
4140  // Default statements partition blocks, so this is the top of the basic block
4141  // we were processing (the "default:" is the label).
4142  DefaultCaseBlock->setLabel(Terminator);
4143 
4144  if (badCFG)
4145  return nullptr;
4146 
4147  // Unlike case statements, we don't add the default block to the successors
4148  // for the switch statement immediately. This is done when we finish
4149  // processing the switch statement. This allows for the default case
4150  // (including a fall-through to the code after the switch statement) to always
4151  // be the last successor of a switch-terminated block.
4152 
4153  // We set Block to NULL to allow lazy creation of a new block (if necessary)
4154  Block = nullptr;
4155 
4156  // This block is now the implicit successor of other blocks.
4157  Succ = DefaultCaseBlock;
4158 
4159  return DefaultCaseBlock;
4160 }
4161 
4162 CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) {
4163  // "try"/"catch" is a control-flow statement. Thus we stop processing the
4164  // current block.
4165  CFGBlock *TrySuccessor = nullptr;
4166 
4167  if (Block) {
4168  if (badCFG)
4169  return nullptr;
4170  TrySuccessor = Block;
4171  } else TrySuccessor = Succ;
4172 
4173  CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock;
4174 
4175  // Create a new block that will contain the try statement.
4176  CFGBlock *NewTryTerminatedBlock = createBlock(false);
4177  // Add the terminator in the try block.
4178  NewTryTerminatedBlock->setTerminator(Terminator);
4179 
4180  bool HasCatchAll = false;
4181  for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) {
4182  // The code after the try is the implicit successor.
4183  Succ = TrySuccessor;
4184  CXXCatchStmt *CS = Terminator->getHandler(h);
4185  if (CS->getExceptionDecl() == nullptr) {
4186  HasCatchAll = true;
4187  }
4188  Block = nullptr;
4189  CFGBlock *CatchBlock = VisitCXXCatchStmt(CS);
4190  if (!CatchBlock)
4191  return nullptr;
4192  // Add this block to the list of successors for the block with the try
4193  // statement.
4194  addSuccessor(NewTryTerminatedBlock, CatchBlock);
4195  }
4196  if (!HasCatchAll) {
4197  if (PrevTryTerminatedBlock)
4198  addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock);
4199  else
4200  addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
4201  }
4202 
4203  // The code after the try is the implicit successor.
4204  Succ = TrySuccessor;
4205 
4206  // Save the current "try" context.
4207  SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock);
4208  cfg->addTryDispatchBlock(TryTerminatedBlock);
4209 
4210  assert(Terminator->getTryBlock() && "try must contain a non-NULL body");
4211  Block = nullptr;
4212  return addStmt(Terminator->getTryBlock());
4213 }
4214 
4215 CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) {
4216  // CXXCatchStmt are treated like labels, so they are the first statement in a
4217  // block.
4218 
4219  // Save local scope position because in case of exception variable ScopePos
4220  // won't be restored when traversing AST.
4221  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
4222 
4223  // Create local scope for possible exception variable.
4224  // Store scope position. Add implicit destructor.
4225  if (VarDecl *VD = CS->getExceptionDecl()) {
4226  LocalScope::const_iterator BeginScopePos = ScopePos;
4227  addLocalScopeForVarDecl(VD);
4228  addAutomaticObjHandling(ScopePos, BeginScopePos, CS);
4229  }
4230 
4231  if (CS->getHandlerBlock())
4232  addStmt(CS->getHandlerBlock());
4233 
4234  CFGBlock *CatchBlock = Block;
4235  if (!CatchBlock)
4236  CatchBlock = createBlock();
4237 
4238  // CXXCatchStmt is more than just a label. They have semantic meaning
4239  // as well, as they implicitly "initialize" the catch variable. Add
4240  // it to the CFG as a CFGElement so that the control-flow of these
4241  // semantics gets captured.
4242  appendStmt(CatchBlock, CS);
4243 
4244  // Also add the CXXCatchStmt as a label, to mirror handling of regular
4245  // labels.
4246  CatchBlock->setLabel(CS);
4247 
4248  // Bail out if the CFG is bad.
4249  if (badCFG)
4250  return nullptr;
4251 
4252  // We set Block to NULL to allow lazy creation of a new block (if necessary)
4253  Block = nullptr;
4254 
4255  return CatchBlock;
4256 }
4257 
4258 CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) {
4259  // C++0x for-range statements are specified as [stmt.ranged]:
4260  //
4261  // {
4262  // auto && __range = range-init;
4263  // for ( auto __begin = begin-expr,
4264  // __end = end-expr;
4265  // __begin != __end;
4266  // ++__begin ) {
4267  // for-range-declaration = *__begin;
4268  // statement
4269  // }
4270  // }
4271 
4272  // Save local scope position before the addition of the implicit variables.
4273  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
4274 
4275  // Create local scopes and destructors for range, begin and end variables.
4276  if (Stmt *Range = S->getRangeStmt())
4277  addLocalScopeForStmt(Range);
4278  if (Stmt *Begin = S->getBeginStmt())
4279  addLocalScopeForStmt(Begin);
4280  if (Stmt *End = S->getEndStmt())
4281  addLocalScopeForStmt(End);
4282  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), S);
4283 
4284  LocalScope::const_iterator ContinueScopePos = ScopePos;
4285 
4286  // "for" is a control-flow statement. Thus we stop processing the current
4287  // block.
4288  CFGBlock *LoopSuccessor = nullptr;
4289  if (Block) {
4290  if (badCFG)
4291  return nullptr;
4292  LoopSuccessor = Block;
4293  } else
4294  LoopSuccessor = Succ;
4295 
4296  // Save the current value for the break targets.
4297  // All breaks should go to the code following the loop.
4298  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
4299  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
4300 
4301  // The block for the __begin != __end expression.
4302  CFGBlock *ConditionBlock = createBlock(false);
4303  ConditionBlock->setTerminator(S);
4304 
4305  // Now add the actual condition to the condition block.
4306  if (Expr *C = S->getCond()) {
4307  Block = ConditionBlock;
4308  CFGBlock *BeginConditionBlock = addStmt(C);
4309  if (badCFG)
4310  return nullptr;
4311  assert(BeginConditionBlock == ConditionBlock &&
4312  "condition block in for-range was unexpectedly complex");
4313  (void)BeginConditionBlock;
4314  }
4315 
4316  // The condition block is the implicit successor for the loop body as well as
4317  // any code above the loop.
4318  Succ = ConditionBlock;
4319 
4320  // See if this is a known constant.
4321  TryResult KnownVal(true);
4322 
4323  if (S->getCond())
4324  KnownVal = tryEvaluateBool(S->getCond());
4325 
4326  // Now create the loop body.
4327  {
4328  assert(S->getBody());
4329 
4330  // Save the current values for Block, Succ, and continue targets.
4331  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
4332  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
4333 
4334  // Generate increment code in its own basic block. This is the target of
4335  // continue statements.
4336  Block = nullptr;
4337  Succ = addStmt(S->getInc());
4338  if (badCFG)
4339  return nullptr;
4340  ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
4341 
4342  // The starting block for the loop increment is the block that should
4343  // represent the 'loop target' for looping back to the start of the loop.
4344  ContinueJumpTarget.block->setLoopTarget(S);
4345 
4346  // Finish up the increment block and prepare to start the loop body.
4347  assert(Block);
4348  if (badCFG)
4349  return nullptr;
4350  Block = nullptr;
4351 
4352  // Add implicit scope and dtors for loop variable.
4353  addLocalScopeAndDtors(S->getLoopVarStmt());
4354 
4355  // Populate a new block to contain the loop body and loop variable.
4356  addStmt(S->getBody());
4357  if (badCFG)
4358  return nullptr;
4359  CFGBlock *LoopVarStmtBlock = addStmt(S->getLoopVarStmt());
4360  if (badCFG)
4361  return nullptr;
4362 
4363  // This new body block is a successor to our condition block.
4364  addSuccessor(ConditionBlock,
4365  KnownVal.isFalse() ? nullptr : LoopVarStmtBlock);
4366  }
4367 
4368  // Link up the condition block with the code that follows the loop (the
4369  // false branch).
4370  addSuccessor(ConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
4371 
4372  // Add the initialization statements.
4373  Block = createBlock();
4374  addStmt(S->getBeginStmt());
4375  addStmt(S->getEndStmt());
4376  CFGBlock *Head = addStmt(S->getRangeStmt());
4377  if (S->getInit())
4378  Head = addStmt(S->getInit());
4379  return Head;
4380 }
4381 
4382 CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E,
4383  AddStmtChoice asc, bool ExternallyDestructed) {
4384  if (BuildOpts.AddTemporaryDtors) {
4385  // If adding implicit destructors visit the full expression for adding
4386  // destructors of temporaries.
4387  TempDtorContext Context;
4388  VisitForTemporaryDtors(E->getSubExpr(), ExternallyDestructed, Context);
4389 
4390  // Full expression has to be added as CFGStmt so it will be sequenced
4391  // before destructors of it's temporaries.
4392  asc = asc.withAlwaysAdd(true);
4393  }
4394  return Visit(E->getSubExpr(), asc);
4395 }
4396 
4397 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
4398  AddStmtChoice asc) {
4399  if (asc.alwaysAdd(*this, E)) {
4400  autoCreateBlock();
4401  appendStmt(Block, E);
4402 
4403  findConstructionContexts(
4404  ConstructionContextLayer::create(cfg->getBumpVectorContext(), E),
4405  E->getSubExpr());
4406 
4407  // We do not want to propagate the AlwaysAdd property.
4408  asc = asc.withAlwaysAdd(false);
4409  }
4410  return Visit(E->getSubExpr(), asc);
4411 }
4412 
4413 CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C,
4414  AddStmtChoice asc) {
4415  // If the constructor takes objects as arguments by value, we need to properly
4416  // construct these objects. Construction contexts we find here aren't for the
4417  // constructor C, they're for its arguments only.
4418  findConstructionContextsForArguments(C);
4419 
4420  autoCreateBlock();
4421  appendConstructor(Block, C);
4422 
4423  return VisitChildren(C);
4424 }
4425 
4426 CFGBlock *CFGBuilder::VisitCXXNewExpr(CXXNewExpr *NE,
4427  AddStmtChoice asc) {
4428  autoCreateBlock();
4429  appendStmt(Block, NE);
4430 
4431  findConstructionContexts(
4432  ConstructionContextLayer::create(cfg->getBumpVectorContext(), NE),
4433  const_cast<CXXConstructExpr *>(NE->getConstructExpr()));
4434 
4435  if (NE->getInitializer())
4436  Block = Visit(NE->getInitializer());
4437 
4438  if (BuildOpts.AddCXXNewAllocator)
4439  appendNewAllocator(Block, NE);
4440 
4441  if (NE->isArray() && *NE->getArraySize())
4442  Block = Visit(*NE->getArraySize());
4443 
4445  E = NE->placement_arg_end(); I != E; ++I)
4446  Block = Visit(*I);
4447 
4448  return Block;
4449 }
4450 
4451 CFGBlock *CFGBuilder::VisitCXXDeleteExpr(CXXDeleteExpr *DE,
4452  AddStmtChoice asc) {
4453  autoCreateBlock();
4454  appendStmt(Block, DE);
4455  QualType DTy = DE->getDestroyedType();
4456  if (!DTy.isNull()) {
4457  DTy = DTy.getNonReferenceType();
4458  CXXRecordDecl *RD = Context->getBaseElementType(DTy)->getAsCXXRecordDecl();
4459  if (RD) {
4460  if (RD->isCompleteDefinition() && !RD->hasTrivialDestructor())
4461  appendDeleteDtor(Block, RD, DE);
4462  }
4463  }
4464 
4465  return VisitChildren(DE);
4466 }
4467 
4468 CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
4469  AddStmtChoice asc) {
4470  if (asc.alwaysAdd(*this, E)) {
4471  autoCreateBlock();
4472  appendStmt(Block, E);
4473  // We do not want to propagate the AlwaysAdd property.
4474  asc = asc.withAlwaysAdd(false);
4475  }
4476  return Visit(E->getSubExpr(), asc);
4477 }
4478 
4479 CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
4480  AddStmtChoice asc) {
4481  // If the constructor takes objects as arguments by value, we need to properly
4482  // construct these objects. Construction contexts we find here aren't for the
4483  // constructor C, they're for its arguments only.
4484  findConstructionContextsForArguments(C);
4485 
4486  autoCreateBlock();
4487  appendConstructor(Block, C);
4488  return VisitChildren(C);
4489 }
4490 
4491 CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E,
4492  AddStmtChoice asc) {
4493  if (asc.alwaysAdd(*this, E)) {
4494  autoCreateBlock();
4495  appendStmt(Block, E);
4496  }
4497  return Visit(E->getSubExpr(), AddStmtChoice());
4498 }
4499 
4500 CFGBlock *CFGBuilder::VisitConstantExpr(ConstantExpr *E, AddStmtChoice asc) {
4501  return Visit(E->getSubExpr(), AddStmtChoice());
4502 }
4503 
4504 CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) {
4505  // Lazily create the indirect-goto dispatch block if there isn't one already.
4506  CFGBlock *IBlock = cfg->getIndirectGotoBlock();
4507 
4508  if (!IBlock) {
4509  IBlock = createBlock(false);
4510  cfg->setIndirectGotoBlock(IBlock);
4511  }
4512 
4513  // IndirectGoto is a control-flow statement. Thus we stop processing the
4514  // current block and create a new one.
4515  if (badCFG)
4516  return nullptr;
4517 
4518  Block = createBlock(false);
4519  Block->setTerminator(I);
4520  addSuccessor(Block, IBlock);
4521  return addStmt(I->getTarget());
4522 }
4523 
4524 CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool ExternallyDestructed,
4525  TempDtorContext &Context) {
4526  assert(BuildOpts.AddImplicitDtors && BuildOpts.AddTemporaryDtors);
4527 
4528 tryAgain:
4529  if (!E) {
4530  badCFG = true;
4531  return nullptr;
4532  }
4533  switch (E->getStmtClass()) {
4534  default:
4535  return VisitChildrenForTemporaryDtors(E, false, Context);
4536 
4537  case Stmt::InitListExprClass:
4538  return VisitChildrenForTemporaryDtors(E, ExternallyDestructed, Context);
4539 
4540  case Stmt::BinaryOperatorClass:
4541  return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E),
4542  ExternallyDestructed,
4543  Context);
4544 
4545  case Stmt::CXXBindTemporaryExprClass:
4546  return VisitCXXBindTemporaryExprForTemporaryDtors(
4547  cast<CXXBindTemporaryExpr>(E), ExternallyDestructed, Context);
4548 
4549  case Stmt::BinaryConditionalOperatorClass:
4550  case Stmt::ConditionalOperatorClass:
4551  return VisitConditionalOperatorForTemporaryDtors(
4552  cast<AbstractConditionalOperator>(E), ExternallyDestructed, Context);
4553 
4554  case Stmt::ImplicitCastExprClass:
4555  // For implicit cast we want ExternallyDestructed to be passed further.
4556  E = cast<CastExpr>(E)->getSubExpr();
4557  goto tryAgain;
4558 
4559  case Stmt::CXXFunctionalCastExprClass:
4560  // For functional cast we want ExternallyDestructed to be passed further.
4561  E = cast<CXXFunctionalCastExpr>(E)->getSubExpr();
4562  goto tryAgain;
4563 
4564  case Stmt::ConstantExprClass:
4565  E = cast<ConstantExpr>(E)->getSubExpr();
4566  goto tryAgain;
4567 
4568  case Stmt::ParenExprClass:
4569  E = cast<ParenExpr>(E)->getSubExpr();
4570  goto tryAgain;
4571 
4572  case Stmt::MaterializeTemporaryExprClass: {
4573  const MaterializeTemporaryExpr* MTE = cast<MaterializeTemporaryExpr>(E);
4574  ExternallyDestructed = (MTE->getStorageDuration() != SD_FullExpression);
4575  SmallVector<const Expr *, 2> CommaLHSs;
4577  // Find the expression whose lifetime needs to be extended.
4578  E = const_cast<Expr *>(
4579  cast<MaterializeTemporaryExpr>(E)
4580  ->GetTemporaryExpr()
4581  ->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments));
4582  // Visit the skipped comma operator left-hand sides for other temporaries.
4583  for (const Expr *CommaLHS : CommaLHSs) {
4584  VisitForTemporaryDtors(const_cast<Expr *>(CommaLHS),
4585  /*ExternallyDestructed=*/false, Context);
4586  }
4587  goto tryAgain;
4588  }
4589 
4590  case Stmt::BlockExprClass:
4591  // Don't recurse into blocks; their subexpressions don't get evaluated
4592  // here.
4593  return Block;
4594 
4595  case Stmt::LambdaExprClass: {
4596  // For lambda expressions, only recurse into the capture initializers,
4597  // and not the body.
4598  auto *LE = cast<LambdaExpr>(E);
4599  CFGBlock *B = Block;
4600  for (Expr *Init : LE->capture_inits()) {
4601  if (Init) {
4602  if (CFGBlock *R = VisitForTemporaryDtors(
4603  Init, /*ExternallyDestructed=*/true, Context))
4604  B = R;
4605  }
4606  }
4607  return B;
4608  }
4609 
4610  case Stmt::StmtExprClass:
4611  // Don't recurse into statement expressions; any cleanups inside them
4612  // will be wrapped in their own ExprWithCleanups.
4613  return Block;
4614 
4615  case Stmt::CXXDefaultArgExprClass:
4616  E = cast<CXXDefaultArgExpr>(E)->getExpr();
4617  goto tryAgain;
4618 
4619  case Stmt::CXXDefaultInitExprClass:
4620  E = cast<CXXDefaultInitExpr>(E)->getExpr();
4621  goto tryAgain;
4622  }
4623 }
4624 
4625 CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E,
4626  bool ExternallyDestructed,
4627  TempDtorContext &Context) {
4628  if (isa<LambdaExpr>(E)) {
4629  // Do not visit the children of lambdas; they have their own CFGs.
4630  return Block;
4631  }
4632 
4633  // When visiting children for destructors we want to visit them in reverse
4634  // order that they will appear in the CFG. Because the CFG is built
4635  // bottom-up, this means we visit them in their natural order, which
4636  // reverses them in the CFG.
4637  CFGBlock *B = Block;
4638  for (Stmt *Child : E->children())
4639  if (Child)
4640  if (CFGBlock *R = VisitForTemporaryDtors(Child, ExternallyDestructed, Context))
4641  B = R;
4642 
4643  return B;
4644 }
4645 
4646 CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(
4647  BinaryOperator *E, bool ExternallyDestructed, TempDtorContext &Context) {
4648  if (E->isCommaOp()) {
4649  // For comma operator LHS expression is visited
4650  // before RHS expression. For destructors visit them in reverse order.
4651  CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), ExternallyDestructed, Context);
4652  CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
4653  return LHSBlock ? LHSBlock : RHSBlock;
4654  }
4655 
4656  if (E->isLogicalOp()) {
4657  VisitForTemporaryDtors(E->getLHS(), false, Context);
4658  TryResult RHSExecuted = tryEvaluateBool(E->getLHS());
4659  if (RHSExecuted.isKnown() && E->getOpcode() == BO_LOr)
4660  RHSExecuted.negate();
4661 
4662  // We do not know at CFG-construction time whether the right-hand-side was
4663  // executed, thus we add a branch node that depends on the temporary
4664  // constructor call.
4665  TempDtorContext RHSContext(
4666  bothKnownTrue(Context.KnownExecuted, RHSExecuted));
4667  VisitForTemporaryDtors(E->getRHS(), false, RHSContext);
4668  InsertTempDtorDecisionBlock(RHSContext);
4669 
4670  return Block;
4671  }
4672 
4673  if (E->isAssignmentOp()) {
4674  // For assignment operator (=) LHS expression is visited
4675  // before RHS expression. For destructors visit them in reverse order.
4676  CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
4677  CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
4678  return LHSBlock ? LHSBlock : RHSBlock;
4679  }
4680 
4681  // For any other binary operator RHS expression is visited before
4682  // LHS expression (order of children). For destructors visit them in reverse
4683  // order.
4684  CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
4685  CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
4686  return RHSBlock ? RHSBlock : LHSBlock;
4687 }
4688 
4689 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors(
4690  CXXBindTemporaryExpr *E, bool ExternallyDestructed, TempDtorContext &Context) {
4691  // First add destructors for temporaries in subexpression.
4692  // Because VisitCXXBindTemporaryExpr calls setDestructed:
4693  CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr(), true, Context);
4694  if (!ExternallyDestructed) {
4695  // If lifetime of temporary is not prolonged (by assigning to constant
4696  // reference) add destructor for it.
4697 
4698  const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor();
4699 
4700  if (Dtor->getParent()->isAnyDestructorNoReturn()) {
4701  // If the destructor is marked as a no-return destructor, we need to
4702  // create a new block for the destructor which does not have as a
4703  // successor anything built thus far. Control won't flow out of this
4704  // block.
4705  if (B) Succ = B;
4706  Block = createNoReturnBlock();
4707  } else if (Context.needsTempDtorBranch()) {
4708  // If we need to introduce a branch, we add a new block that we will hook
4709  // up to a decision block later.
4710  if (B) Succ = B;
4711  Block = createBlock();
4712  } else {
4713  autoCreateBlock();
4714  }
4715  if (Context.needsTempDtorBranch()) {
4716  Context.setDecisionPoint(Succ, E);
4717  }
4718  appendTemporaryDtor(Block, E);
4719 
4720  B = Block;
4721  }
4722  return B;
4723 }
4724 
4725 void CFGBuilder::InsertTempDtorDecisionBlock(const TempDtorContext &Context,
4726  CFGBlock *FalseSucc) {
4727  if (!Context.TerminatorExpr) {
4728  // If no temporary was found, we do not need to insert a decision point.
4729  return;
4730  }
4731  assert(Context.TerminatorExpr);
4732  CFGBlock *Decision = createBlock(false);
4733  Decision->setTerminator(CFGTerminator(Context.TerminatorExpr,
4735  addSuccessor(Decision, Block, !Context.KnownExecuted.isFalse());
4736  addSuccessor(Decision, FalseSucc ? FalseSucc : Context.Succ,
4737  !Context.KnownExecuted.isTrue());
4738  Block = Decision;
4739 }
4740 
4741 CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors(
4742  AbstractConditionalOperator *E, bool ExternallyDestructed,
4743  TempDtorContext &Context) {
4744  VisitForTemporaryDtors(E->getCond(), false, Context);
4745  CFGBlock *ConditionBlock = Block;
4746  CFGBlock *ConditionSucc = Succ;
4747  TryResult ConditionVal = tryEvaluateBool(E->getCond());
4748  TryResult NegatedVal = ConditionVal;
4749  if (NegatedVal.isKnown()) NegatedVal.negate();
4750 
4751  TempDtorContext TrueContext(
4752  bothKnownTrue(Context.KnownExecuted, ConditionVal));
4753  VisitForTemporaryDtors(E->getTrueExpr(), ExternallyDestructed, TrueContext);
4754  CFGBlock *TrueBlock = Block;
4755 
4756  Block = ConditionBlock;
4757  Succ = ConditionSucc;
4758  TempDtorContext FalseContext(
4759  bothKnownTrue(Context.KnownExecuted, NegatedVal));
4760  VisitForTemporaryDtors(E->getFalseExpr(), ExternallyDestructed, FalseContext);
4761 
4762  if (TrueContext.TerminatorExpr && FalseContext.TerminatorExpr) {
4763  InsertTempDtorDecisionBlock(FalseContext, TrueBlock);
4764  } else if (TrueContext.TerminatorExpr) {
4765  Block = TrueBlock;
4766  InsertTempDtorDecisionBlock(TrueContext);
4767  } else {
4768  InsertTempDtorDecisionBlock(FalseContext);
4769  }
4770  return Block;
4771 }
4772 
4773 CFGBlock *CFGBuilder::VisitOMPExecutableDirective(OMPExecutableDirective *D,
4774  AddStmtChoice asc) {
4775  if (asc.alwaysAdd(*this, D)) {
4776  autoCreateBlock();
4777  appendStmt(Block, D);
4778  }
4779 
4780  // Iterate over all used expression in clauses.
4781  CFGBlock *B = Block;
4782 
4783  // Reverse the elements to process them in natural order. Iterators are not
4784  // bidirectional, so we need to create temp vector.
4787  for (Stmt *S : llvm::reverse(Used)) {
4788  assert(S && "Expected non-null used-in-clause child.");
4789  if (CFGBlock *R = Visit(S))
4790  B = R;
4791  }
4792  // Visit associated structured block if any.
4793  if (!D->isStandaloneDirective())
4794  if (Stmt *S = D->getStructuredBlock()) {
4795  if (!isa<CompoundStmt>(S))
4796  addLocalScopeAndDtors(S);
4797  if (CFGBlock *R = addStmt(S))
4798  B = R;
4799  }
4800 
4801  return B;
4802 }
4803 
4804 /// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has
4805 /// no successors or predecessors. If this is the first block created in the
4806 /// CFG, it is automatically set to be the Entry and Exit of the CFG.
4808  bool first_block = begin() == end();
4809 
4810  // Create the block.
4811  CFGBlock *Mem = getAllocator().Allocate<CFGBlock>();
4812  new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this);
4813  Blocks.push_back(Mem, BlkBVC);
4814 
4815  // If this is the first block, set it as the Entry and Exit.
4816  if (first_block)
4817  Entry = Exit = &back();
4818 
4819  // Return the block.
4820  return &back();
4821 }
4822 
4823 /// buildCFG - Constructs a CFG from an AST.
4824 std::unique_ptr<CFG> CFG::buildCFG(const Decl *D, Stmt *Statement,
4825  ASTContext *C, const BuildOptions &BO) {
4826  CFGBuilder Builder(C, BO);
4827  return Builder.buildCFG(D, Statement);
4828 }
4829 
4830 bool CFG::isLinear() const {
4831  // Quick path: if we only have the ENTRY block, the EXIT block, and some code
4832  // in between, then we have no room for control flow.
4833  if (size() <= 3)
4834  return true;
4835 
4836  // Traverse the CFG until we find a branch.
4837  // TODO: While this should still be very fast,
4838  // maybe we should cache the answer.
4839  llvm::SmallPtrSet<const CFGBlock *, 4> Visited;
4840  const CFGBlock *B = Entry;
4841  while (B != Exit) {
4842  auto IteratorAndFlag = Visited.insert(B);
4843  if (!IteratorAndFlag.second) {
4844  // We looped back to a block that we've already visited. Not linear.
4845  return false;
4846  }
4847 
4848  // Iterate over reachable successors.
4849  const CFGBlock *FirstReachableB = nullptr;
4850  for (const CFGBlock::AdjacentBlock &AB : B->succs()) {
4851  if (!AB.isReachable())
4852  continue;
4853 
4854  if (FirstReachableB == nullptr) {
4855  FirstReachableB = &*AB;
4856  } else {
4857  // We've encountered a branch. It's not a linear CFG.
4858  return false;
4859  }
4860  }
4861 
4862  if (!FirstReachableB) {
4863  // We reached a dead end. EXIT is unreachable. This is linear enough.
4864  return true;
4865  }
4866 
4867  // There's only one way to move forward. Proceed.
4868  B = FirstReachableB;
4869  }
4870 
4871  // We reached EXIT and found no branches.
4872  return true;
4873 }
4874 
4875 const CXXDestructorDecl *
4877  switch (getKind()) {
4880  case CFGElement::LoopExit:
4882  case CFGElement::Statement:
4886  case CFGElement::ScopeEnd:
4887  llvm_unreachable("getDestructorDecl should only be used with "
4888  "ImplicitDtors");
4890  const VarDecl *var = castAs<CFGAutomaticObjDtor>().getVarDecl();
4891  QualType ty = var->getType();
4892 
4893  // FIXME: See CFGBuilder::addLocalScopeForVarDecl.
4894  //
4895  // Lifetime-extending constructs are handled here. This works for a single
4896  // temporary in an initializer expression.
4897  if (ty->isReferenceType()) {
4898  if (const Expr *Init = var->getInit()) {
4899  ty = getReferenceInitTemporaryType(Init);
4900  }
4901  }
4902 
4903  while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) {
4904  ty = arrayType->getElementType();
4905  }
4906 
4907  // The situation when the type of the lifetime-extending reference
4908  // does not correspond to the type of the object is supposed
4909  // to be handled by now. In particular, 'ty' is now the unwrapped
4910  // record type.
4911  const CXXRecordDecl *classDecl = ty->getAsCXXRecordDecl();
4912  assert(classDecl);
4913  return classDecl->getDestructor();
4914  }
4915  case CFGElement::DeleteDtor: {
4916  const CXXDeleteExpr *DE = castAs<CFGDeleteDtor>().getDeleteExpr();
4917  QualType DTy = DE->getDestroyedType();
4918  DTy = DTy.getNonReferenceType();
4919  const CXXRecordDecl *classDecl =
4920  astContext.getBaseElementType(DTy)->getAsCXXRecordDecl();
4921  return classDecl->getDestructor();
4922  }
4924  const CXXBindTemporaryExpr *bindExpr =
4925  castAs<CFGTemporaryDtor>().getBindTemporaryExpr();
4926  const CXXTemporary *temp = bindExpr->getTemporary();
4927  return temp->getDestructor();
4928  }
4929  case CFGElement::BaseDtor:
4931  // Not yet supported.
4932  return nullptr;
4933  }
4934  llvm_unreachable("getKind() returned bogus value");
4935 }
4936 
4937 //===----------------------------------------------------------------------===//
4938 // CFGBlock operations.
4939 //===----------------------------------------------------------------------===//
4940 
4942  : ReachableBlock(IsReachable ? B : nullptr),
4943  UnreachableBlock(!IsReachable ? B : nullptr,
4944  B && IsReachable ? AB_Normal : AB_Unreachable) {}
4945 
4947  : ReachableBlock(B),
4948  UnreachableBlock(B == AlternateBlock ? nullptr : AlternateBlock,
4949  B == AlternateBlock ? AB_Alternate : AB_Normal) {}
4950 
4952  BumpVectorContext &C) {
4953  if (CFGBlock *B = Succ.getReachableBlock())
4954  B->Preds.push_back(AdjacentBlock(this, Succ.isReachable()), C);
4955 
4956  if (CFGBlock *UnreachableB = Succ.getPossiblyUnreachableBlock())
4957  UnreachableB->Preds.push_back(AdjacentBlock(this, false), C);
4958 
4959  Succs.push_back(Succ, C);
4960 }
4961 
4963  const CFGBlock *From, const CFGBlock *To) {
4964  if (F.IgnoreNullPredecessors && !From)
4965  return true;
4966 
4967  if (To && From && F.IgnoreDefaultsWithCoveredEnums) {
4968  // If the 'To' has no label or is labeled but the label isn't a
4969  // CaseStmt then filter this edge.
4970  if (const SwitchStmt *S =
4971  dyn_cast_or_null<SwitchStmt>(From->getTerminatorStmt())) {
4972  if (S->isAllEnumCasesCovered()) {
4973  const Stmt *L = To->getLabel();
4974  if (!L || !isa<CaseStmt>(L))
4975  return true;
4976  }
4977  }
4978  }
4979 
4980  return false;
4981 }
4982 
4983 //===----------------------------------------------------------------------===//
4984 // CFG pretty printing
4985 //===----------------------------------------------------------------------===//
4986 
4987 namespace {
4988 
4989 class StmtPrinterHelper : public PrinterHelper {
4990  using StmtMapTy = llvm::DenseMap<const Stmt *, std::pair<unsigned, unsigned>>;
4991  using DeclMapTy = llvm::DenseMap<const Decl *, std::pair<unsigned, unsigned>>;
4992 
4993  StmtMapTy StmtMap;
4994  DeclMapTy DeclMap;
4995  signed currentBlock = 0;
4996  unsigned currStmt = 0;
4997  const LangOptions &LangOpts;
4998 
4999 public:
5000  StmtPrinterHelper(const CFG* cfg, const LangOptions &LO)
5001  : LangOpts(LO) {
5002  if (!cfg)
5003  return;
5004  for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) {
5005  unsigned j = 1;
5006  for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ;
5007  BI != BEnd; ++BI, ++j ) {
5008  if (Optional<CFGStmt> SE = BI->getAs<CFGStmt>()) {
5009  const Stmt *stmt= SE->getStmt();
5010  std::pair<unsigned, unsigned> P((*I)->getBlockID(), j);
5011  StmtMap[stmt] = P;
5012 
5013  switch (stmt->getStmtClass()) {
5014  case Stmt::DeclStmtClass:
5015  DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P;
5016  break;
5017  case Stmt::IfStmtClass: {
5018  const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable();
5019  if (var)
5020  DeclMap[var] = P;
5021  break;
5022  }
5023  case Stmt::ForStmtClass: {
5024  const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable();
5025  if (var)
5026  DeclMap[var] = P;
5027  break;
5028  }
5029  case Stmt::WhileStmtClass: {
5030  const VarDecl *var =
5031  cast<WhileStmt>(stmt)->getConditionVariable();
5032  if (var)
5033  DeclMap[var] = P;
5034  break;
5035  }
5036  case Stmt::SwitchStmtClass: {
5037  const VarDecl *var =
5038  cast<SwitchStmt>(stmt)->getConditionVariable();
5039  if (var)
5040  DeclMap[var] = P;
5041  break;
5042  }
5043  case Stmt::CXXCatchStmtClass: {
5044  const VarDecl *var =
5045  cast<CXXCatchStmt>(stmt)->getExceptionDecl();
5046  if (var)
5047  DeclMap[var] = P;
5048  break;
5049  }
5050  default:
5051  break;
5052  }
5053  }
5054  }
5055  }
5056  }
5057 
5058  ~StmtPrinterHelper() override = default;
5059 
5060  const LangOptions &getLangOpts() const { return LangOpts; }
5061  void setBlockID(signed i) { currentBlock = i; }
5062  void setStmtID(unsigned i) { currStmt = i; }
5063 
5064  bool handledStmt(Stmt *S, raw_ostream &OS) override {
5065  StmtMapTy::iterator I = StmtMap.find(S);
5066 
5067  if (I == StmtMap.end())
5068  return false;
5069 
5070  if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
5071  && I->second.second == currStmt) {
5072  return false;
5073  }
5074 
5075  OS << "[B" << I->second.first << "." << I->second.second << "]";
5076  return true;
5077  }
5078 
5079  bool handleDecl(const Decl *D, raw_ostream &OS) {
5080  DeclMapTy::iterator I = DeclMap.find(D);
5081 
5082  if (I == DeclMap.end())
5083  return false;
5084 
5085  if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
5086  && I->second.second == currStmt) {
5087  return false;
5088  }
5089 
5090  OS << "[B" << I->second.first << "." << I->second.second << "]";
5091  return true;
5092  }
5093 };
5094 
5095 class CFGBlockTerminatorPrint
5096  : public StmtVisitor<CFGBlockTerminatorPrint,void> {
5097  raw_ostream &OS;
5098  StmtPrinterHelper* Helper;
5099  PrintingPolicy Policy;
5100 
5101 public:
5102  CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper,
5103  const PrintingPolicy &Policy)
5104  : OS(os), Helper(helper), Policy(Policy) {
5105  this->Policy.IncludeNewlines = false;
5106  }
5107 
5108  void VisitIfStmt(IfStmt *I) {
5109  OS << "if ";
5110  if (Stmt *C = I->getCond())
5111  C->printPretty(OS, Helper, Policy);
5112  }
5113 
5114  // Default case.
5115  void VisitStmt(Stmt *Terminator) {
5116  Terminator->printPretty(OS, Helper, Policy);
5117  }
5118 
5119  void VisitDeclStmt(DeclStmt *DS) {
5120  VarDecl *VD = cast<VarDecl>(DS->getSingleDecl());
5121  OS << "static init " << VD->getName();
5122  }
5123 
5124  void VisitForStmt(ForStmt *F) {
5125  OS << "for (" ;
5126  if (F->getInit())
5127  OS << "...";
5128  OS << "; ";
5129  if (Stmt *C = F->getCond())
5130  C->printPretty(OS, Helper, Policy);
5131  OS << "; ";
5132  if (F->getInc())
5133  OS << "...";
5134  OS << ")";
5135  }
5136 
5137  void VisitWhileStmt(WhileStmt *W) {
5138  OS << "while " ;
5139  if (Stmt *C = W->getCond())
5140  C->printPretty(OS, Helper, Policy);
5141  }
5142 
5143  void VisitDoStmt(DoStmt *D) {
5144  OS << "do ... while ";
5145  if (Stmt *C = D->getCond())
5146  C->printPretty(OS, Helper, Policy);
5147  }
5148 
5149  void VisitSwitchStmt(SwitchStmt *Terminator) {
5150  OS << "switch ";
5151  Terminator->getCond()->printPretty(OS, Helper, Policy);
5152  }
5153 
5154  void VisitCXXTryStmt(CXXTryStmt *CS) {
5155  OS << "try ...";
5156  }
5157 
5158  void VisitSEHTryStmt(SEHTryStmt *CS) {
5159  OS << "__try ...";
5160  }
5161 
5162  void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) {
5163  if (Stmt *Cond = C->getCond())
5164  Cond->printPretty(OS, Helper, Policy);
5165  OS << " ? ... : ...";
5166  }
5167 
5168  void VisitChooseExpr(ChooseExpr *C) {
5169  OS << "__builtin_choose_expr( ";
5170  if (Stmt *Cond = C->getCond())
5171  Cond->printPretty(OS, Helper, Policy);
5172  OS << " )";
5173  }
5174 
5175  void VisitIndirectGotoStmt(IndirectGotoStmt *I) {
5176  OS << "goto *";
5177  if (Stmt *T = I->getTarget())
5178  T->printPretty(OS, Helper, Policy);
5179  }
5180 
5181  void VisitBinaryOperator(BinaryOperator* B) {
5182  if (!B->isLogicalOp()) {
5183  VisitExpr(B);
5184  return;
5185  }
5186 
5187  if (B->getLHS())
5188  B->getLHS()->printPretty(OS, Helper, Policy);
5189 
5190  switch (B->getOpcode()) {
5191  case BO_LOr:
5192  OS << " || ...";
5193  return;
5194  case BO_LAnd:
5195  OS << " && ...";
5196  return;
5197  default:
5198  llvm_unreachable("Invalid logical operator.");
5199  }
5200  }
5201 
5202  void VisitExpr(Expr *E) {
5203  E->printPretty(OS, Helper, Policy);
5204  }
5205 
5206 public:
5207  void print(CFGTerminator T) {
5208  switch (T.getKind()) {
5210  Visit(T.getStmt());
5211  break;
5213  OS << "(Temp Dtor) ";
5214  Visit(T.getStmt());
5215  break;
5217  OS << "(See if most derived ctor has already initialized vbases)";
5218  break;
5219  }
5220  }
5221 };
5222 
5223 } // namespace
5224 
5225 static void print_initializer(raw_ostream &OS, StmtPrinterHelper &Helper,
5226  const CXXCtorInitializer *I) {
5227  if (I->isBaseInitializer())
5228  OS << I->getBaseClass()->getAsCXXRecordDecl()->getName();
5229  else if (I->isDelegatingInitializer())
5231  else
5232  OS << I->getAnyMember()->getName();
5233  OS << "(";
5234  if (Expr *IE = I->getInit())
5235  IE->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
5236  OS << ")";
5237 
5238  if (I->isBaseInitializer())
5239  OS << " (Base initializer)";
5240  else if (I->isDelegatingInitializer())
5241  OS << " (Delegating initializer)";
5242  else
5243  OS << " (Member initializer)";
5244 }
5245 
5246 static void print_construction_context(raw_ostream &OS,
5247  StmtPrinterHelper &Helper,
5248  const ConstructionContext *CC) {
5250  switch (CC->getKind()) {
5252  OS << ", ";
5253  const auto *SICC = cast<SimpleConstructorInitializerConstructionContext>(CC);
5254  print_initializer(OS, Helper, SICC->getCXXCtorInitializer());
5255  return;
5256  }
5258  OS << ", ";
5259  const auto *CICC =
5260  cast<CXX17ElidedCopyConstructorInitializerConstructionContext>(CC);
5261  print_initializer(OS, Helper, CICC->getCXXCtorInitializer());
5262  Stmts.push_back(CICC->getCXXBindTemporaryExpr());
5263  break;
5264  }
5266  const auto *SDSCC = cast<SimpleVariableConstructionContext>(CC);
5267  Stmts.push_back(SDSCC->getDeclStmt());
5268  break;
5269  }
5271  const auto *CDSCC = cast<CXX17ElidedCopyVariableConstructionContext>(CC);
5272  Stmts.push_back(CDSCC->getDeclStmt());
5273  Stmts.push_back(CDSCC->getCXXBindTemporaryExpr());
5274  break;
5275  }
5277  const auto *NECC = cast<NewAllocatedObjectConstructionContext>(CC);
5278  Stmts.push_back(NECC->getCXXNewExpr());
5279  break;
5280  }
5282  const auto *RSCC = cast<SimpleReturnedValueConstructionContext>(CC);
5283  Stmts.push_back(RSCC->getReturnStmt());
5284  break;
5285  }
5287  const auto *RSCC =
5288  cast<CXX17ElidedCopyReturnedValueConstructionContext>(CC);
5289  Stmts.push_back(RSCC->getReturnStmt());
5290  Stmts.push_back(RSCC->getCXXBindTemporaryExpr());
5291  break;
5292  }
5294  const auto *TOCC = cast<SimpleTemporaryObjectConstructionContext>(CC);
5295  Stmts.push_back(TOCC->getCXXBindTemporaryExpr());
5296  Stmts.push_back(TOCC->getMaterializedTemporaryExpr());
5297  break;
5298  }
5300  const auto *TOCC = cast<ElidedTemporaryObjectConstructionContext>(CC);
5301  Stmts.push_back(TOCC->getCXXBindTemporaryExpr());
5302  Stmts.push_back(TOCC->getMaterializedTemporaryExpr());
5303  Stmts.push_back(TOCC->getConstructorAfterElision());
5304  break;
5305  }
5307  const auto *ACC = cast<ArgumentConstructionContext>(CC);
5308  if (const Stmt *BTE = ACC->getCXXBindTemporaryExpr()) {
5309  OS << ", ";
5310  Helper.handledStmt(const_cast<Stmt *>(BTE), OS);
5311  }
5312  OS << ", ";
5313  Helper.handledStmt(const_cast<Expr *>(ACC->getCallLikeExpr()), OS);
5314  OS << "+" << ACC->getIndex();
5315  return;
5316  }
5317  }
5318  for (auto I: Stmts)
5319  if (I) {
5320  OS << ", ";
5321  Helper.handledStmt(const_cast<Stmt *>(I), OS);
5322  }
5323 }
5324 
5325 static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
5326  const CFGElement &E);
5327 
5328 void CFGElement::dumpToStream(llvm::raw_ostream &OS) const {
5329  StmtPrinterHelper Helper(nullptr, {});
5330  print_elem(OS, Helper, *this);
5331 }
5332 
5333 static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
5334  const CFGElement &E) {
5335  switch (E.getKind()) {
5336  case CFGElement::Kind::Statement:
5337  case CFGElement::Kind::CXXRecordTypedCall:
5338  case CFGElement::Kind::Constructor: {
5339  CFGStmt CS = E.castAs<CFGStmt>();
5340  const Stmt *S = CS.getStmt();
5341  assert(S != nullptr && "Expecting non-null Stmt");
5342 
5343  // special printing for statement-expressions.
5344  if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) {
5345  const CompoundStmt *Sub = SE->getSubStmt();
5346 
5347  auto Children = Sub->children();
5348  if (Children.begin() != Children.end()) {
5349  OS << "({ ... ; ";
5350  Helper.handledStmt(*SE->getSubStmt()->body_rbegin(),OS);
5351  OS << " })\n";
5352  return;
5353  }
5354  }
5355  // special printing for comma expressions.
5356  if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) {
5357  if (B->getOpcode() == BO_Comma) {
5358  OS << "... , ";
5359  Helper.handledStmt(B->getRHS(),OS);
5360  OS << '\n';
5361  return;
5362  }
5363  }
5364  S->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
5365 
5366  if (auto VTC = E.getAs<CFGCXXRecordTypedCall>()) {
5367  if (isa<CXXOperatorCallExpr>(S))
5368  OS << " (OperatorCall)";
5369  OS << " (CXXRecordTypedCall";
5370  print_construction_context(OS, Helper, VTC->getConstructionContext());
5371  OS << ")";
5372  } else if (isa<CXXOperatorCallExpr>(S)) {
5373  OS << " (OperatorCall)";
5374  } else if (isa<CXXBindTemporaryExpr>(S)) {
5375  OS << " (BindTemporary)";
5376  } else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) {
5377  OS << " (CXXConstructExpr";
5379  print_construction_context(OS, Helper, CE->getConstructionContext());
5380  }
5381  OS << ", " << CCE->getType().getAsString() << ")";
5382  } else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) {
5383  OS << " (" << CE->getStmtClassName() << ", "
5384  << CE->getCastKindName()
5385  << ", " << CE->getType().getAsString()
5386  << ")";
5387  }
5388 
5389  // Expressions need a newline.
5390  if (isa<Expr>(S))
5391  OS << '\n';
5392 
5393  break;
5394  }
5395 
5396  case CFGElement::Kind::Initializer:
5398  OS << '\n';
5399  break;
5400 
5401  case CFGElement::Kind::AutomaticObjectDtor: {
5403  const VarDecl *VD = DE.getVarDecl();
5404  Helper.handleDecl(VD, OS);
5405 
5406  QualType T = VD->getType();
5407  if (T->isReferenceType())
5408  T = getReferenceInitTemporaryType(VD->getInit(), nullptr);
5409 
5410  OS << ".~";
5411  T.getUnqualifiedType().print(OS, PrintingPolicy(Helper.getLangOpts()));
5412  OS << "() (Implicit destructor)\n";
5413  break;
5414  }
5415 
5416  case CFGElement::Kind::LifetimeEnds:
5417  Helper.handleDecl(E.castAs<CFGLifetimeEnds>().getVarDecl(), OS);
5418  OS << " (Lifetime ends)\n";
5419  break;
5420 
5421  case CFGElement::Kind::LoopExit:
5422  OS << E.castAs<CFGLoopExit>().getLoopStmt()->getStmtClassName() << " (LoopExit)\n";
5423  break;
5424 
5425  case CFGElement::Kind::ScopeBegin:
5426  OS << "CFGScopeBegin(";
5427  if (const VarDecl *VD = E.castAs<CFGScopeBegin>().getVarDecl())
5428  OS << VD->getQualifiedNameAsString();
5429  OS << ")\n";
5430  break;
5431 
5432  case CFGElement::Kind::ScopeEnd:
5433  OS << "CFGScopeEnd(";
5434  if (const VarDecl *VD = E.castAs<CFGScopeEnd>().getVarDecl())
5435  OS << VD->getQualifiedNameAsString();
5436  OS << ")\n";
5437  break;
5438 
5439  case CFGElement::Kind::NewAllocator:
5440  OS << "CFGNewAllocator(";
5441  if (const CXXNewExpr *AllocExpr = E.castAs<CFGNewAllocator>().getAllocatorExpr())
5442  AllocExpr->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
5443  OS << ")\n";
5444  break;
5445 
5446  case CFGElement::Kind::DeleteDtor: {
5448  const CXXRecordDecl *RD = DE.getCXXRecordDecl();
5449  if (!RD)
5450  return;
5451  CXXDeleteExpr *DelExpr =
5452  const_cast<CXXDeleteExpr*>(DE.getDeleteExpr());
5453  Helper.handledStmt(cast<Stmt>(DelExpr->getArgument()), OS);
5454  OS << "->~" << RD->getName().str() << "()";
5455  OS << " (Implicit destructor)\n";
5456  break;
5457  }
5458 
5459  case CFGElement::Kind::BaseDtor: {
5460  const CXXBaseSpecifier *BS = E.castAs<CFGBaseDtor>().getBaseSpecifier();
5461  OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()";
5462  OS << " (Base object destructor)\n";
5463  break;
5464  }
5465 
5466  case CFGElement::Kind::MemberDtor: {
5467  const FieldDecl *FD = E.castAs<CFGMemberDtor>().getFieldDecl();
5468  const Type *T = FD->getType()->getBaseElementTypeUnsafe();
5469  OS << "this->" << FD->getName();
5470  OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()";
5471  OS << " (Member object destructor)\n";
5472  break;
5473  }
5474 
5475  case CFGElement::Kind::TemporaryDtor: {
5476  const CXXBindTemporaryExpr *BT = E.castAs<CFGTemporaryDtor>().getBindTemporaryExpr();
5477  OS << "~";
5478  BT->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
5479  OS << "() (Temporary object destructor)\n";
5480  break;
5481  }
5482  }
5483 }
5484 
5485 static void print_block(raw_ostream &OS, const CFG* cfg,
5486  const CFGBlock &B,
5487  StmtPrinterHelper &Helper, bool print_edges,
5488  bool ShowColors) {
5489  Helper.setBlockID(B.getBlockID());
5490 
5491  // Print the header.
5492  if (ShowColors)
5493  OS.changeColor(raw_ostream::YELLOW, true);
5494 
5495  OS << "\n [B" << B.getBlockID();
5496 
5497  if (&B == &cfg->getEntry())
5498  OS << " (ENTRY)]\n";
5499  else if (&B == &cfg->getExit())
5500  OS << " (EXIT)]\n";
5501  else if (&B == cfg->getIndirectGotoBlock())
5502  OS << " (INDIRECT GOTO DISPATCH)]\n";
5503  else if (B.hasNoReturnElement())
5504  OS << " (NORETURN)]\n";
5505  else
5506  OS << "]\n";
5507 
5508  if (ShowColors)
5509  OS.resetColor();
5510 
5511  // Print the label of this block.
5512  if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) {
5513  if (print_edges)
5514  OS << " ";
5515 
5516  if (LabelStmt *L = dyn_cast<LabelStmt>(Label))
5517  OS << L->getName();
5518  else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) {
5519  OS << "case ";
5520  if (C->getLHS())
5521  C->getLHS()->printPretty(OS, &Helper,
5522  PrintingPolicy(Helper.getLangOpts()));
5523  if (C->getRHS()) {
5524  OS << " ... ";
5525  C->getRHS()->printPretty(OS, &Helper,
5526  PrintingPolicy(Helper.getLangOpts()));
5527  }
5528  } else if (isa<DefaultStmt>(Label))
5529  OS << "default";
5530  else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) {
5531  OS << "catch (";
5532  if (CS->getExceptionDecl())
5533  CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper.getLangOpts()),
5534  0);
5535  else
5536  OS << "...";
5537  OS << ")";
5538  } else if (SEHExceptStmt *ES = dyn_cast<SEHExceptStmt>(Label)) {
5539  OS << "__except (";
5540  ES->getFilterExpr()->printPretty(OS, &Helper,
5541  PrintingPolicy(Helper.getLangOpts()), 0);
5542  OS << ")";
5543  } else
5544  llvm_unreachable("Invalid label statement in CFGBlock.");
5545 
5546  OS << ":\n";
5547  }
5548 
5549  // Iterate through the statements in the block and print them.
5550  unsigned j = 1;
5551 
5552  for (CFGBlock::const_iterator I = B.begin(), E = B.end() ;
5553  I != E ; ++I, ++j ) {
5554  // Print the statement # in the basic block and the statement itself.
5555  if (print_edges)
5556  OS << " ";
5557 
5558  OS << llvm::format("%3d", j) << ": ";
5559 
5560  Helper.setStmtID(j);
5561 
5562  print_elem(OS, Helper, *I);
5563  }
5564 
5565  // Print the terminator of this block.
5566  if (B.getTerminator().isValid()) {
5567  if (ShowColors)
5568  OS.changeColor(raw_ostream::GREEN);
5569 
5570  OS << " T: ";
5571 
5572  Helper.setBlockID(-1);
5573 
5574  PrintingPolicy PP(Helper.getLangOpts());
5575  CFGBlockTerminatorPrint TPrinter(OS, &Helper, PP);
5576  TPrinter.print(B.getTerminator());
5577  OS << '\n';
5578 
5579  if (ShowColors)
5580  OS.resetColor();
5581  }
5582 
5583  if (print_edges) {
5584  // Print the predecessors of this block.
5585  if (!B.pred_empty()) {
5586  const raw_ostream::Colors Color = raw_ostream::BLUE;
5587  if (ShowColors)
5588  OS.changeColor(Color);
5589  OS << " Preds " ;
5590  if (ShowColors)
5591  OS.resetColor();
5592  OS << '(' << B.pred_size() << "):";
5593  unsigned i = 0;
5594 
5595  if (ShowColors)
5596  OS.changeColor(Color);
5597 
5598  for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end();
5599  I != E; ++I, ++i) {
5600  if (i % 10 == 8)
5601  OS << "\n ";
5602 
5603  CFGBlock *B = *I;
5604  bool Reachable = true;
5605  if (!B) {
5606  Reachable = false;
5607  B = I->getPossiblyUnreachableBlock();
5608  }
5609 
5610  OS << " B" << B->getBlockID();
5611  if (!Reachable)
5612  OS << "(Unreachable)";
5613  }
5614 
5615  if (ShowColors)
5616  OS.resetColor();
5617 
5618  OS << '\n';
5619  }
5620 
5621  // Print the successors of this block.
5622  if (!B.succ_empty()) {
5623  const raw_ostream::Colors Color = raw_ostream::MAGENTA;
5624  if (ShowColors)
5625  OS.changeColor(Color);
5626  OS << " Succs ";
5627  if (ShowColors)
5628  OS.resetColor();
5629  OS << '(' << B.succ_size() << "):";
5630  unsigned i = 0;
5631 
5632  if (ShowColors)
5633  OS.changeColor(Color);
5634 
5635  for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end();
5636  I != E; ++I, ++i) {
5637  if (i % 10 == 8)
5638  OS << "\n ";
5639 
5640  CFGBlock *B = *I;
5641 
5642  bool Reachable = true;
5643  if (!B) {
5644  Reachable = false;
5645  B = I->getPossiblyUnreachableBlock();
5646  }
5647 
5648  if (B) {
5649  OS << " B" << B->getBlockID();
5650  if (!Reachable)
5651  OS << "(Unreachable)";
5652  }
5653  else {
5654  OS << " NULL";
5655  }
5656  }
5657 
5658  if (ShowColors)
5659  OS.resetColor();
5660  OS << '\n';
5661  }
5662  }
5663 }
5664 
5665 /// dump - A simple pretty printer of a CFG that outputs to stderr.
5666 void CFG::dump(const LangOptions &LO, bool ShowColors) const {
5667  print(llvm::errs(), LO, ShowColors);
5668 }
5669 
5670 /// print - A simple pretty printer of a CFG that outputs to an ostream.
5671 void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const {
5672  StmtPrinterHelper Helper(this, LO);
5673 
5674  // Print the entry block.
5675  print_block(OS, this, getEntry(), Helper, true, ShowColors);
5676 
5677  // Iterate through the CFGBlocks and print them one by one.
5678  for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) {
5679  // Skip the entry block, because we already printed it.
5680  if (&(**I) == &getEntry() || &(**I) == &getExit())
5681  continue;
5682 
5683  print_block(OS, this, **I, Helper, true, ShowColors);
5684  }
5685 
5686  // Print the exit block.
5687  print_block(OS, this, getExit(), Helper, true, ShowColors);
5688  OS << '\n';
5689  OS.flush();
5690 }
5691 
5692 size_t CFGBlock::getIndexInCFG() const {
5693  return llvm::find(*getParent(), this) - getParent()->begin();
5694 }
5695 
5696 /// dump - A simply pretty printer of a CFGBlock that outputs to stderr.
5697 void CFGBlock::dump(const CFG* cfg, const LangOptions &LO,
5698  bool ShowColors) const {
5699  print(llvm::errs(), cfg, LO, ShowColors);
5700 }
5701 
5702 LLVM_DUMP_METHOD void CFGBlock::dump() const {
5703  dump(getParent(), LangOptions(), false);
5704 }
5705 
5706 /// print - A simple pretty printer of a CFGBlock that outputs to an ostream.
5707 /// Generally this will only be called from CFG::print.
5708 void CFGBlock::print(raw_ostream &OS, const CFG* cfg,
5709  const LangOptions &LO, bool ShowColors) const {
5710  StmtPrinterHelper Helper(cfg, LO);
5711  print_block(OS, cfg, *this, Helper, true, ShowColors);
5712  OS << '\n';
5713 }
5714 
5715 /// printTerminator - A simple pretty printer of the terminator of a CFGBlock.
5716 void CFGBlock::printTerminator(raw_ostream &OS,
5717  const LangOptions &LO) const {
5718  CFGBlockTerminatorPrint TPrinter(OS, nullptr, PrintingPolicy(LO));
5719  TPrinter.print(getTerminator());
5720 }
5721 
5722 /// printTerminatorJson - Pretty-prints the terminator in JSON format.
5723 void CFGBlock::printTerminatorJson(raw_ostream &Out, const LangOptions &LO,
5724  bool AddQuotes) const {
5725  std::string Buf;
5726  llvm::raw_string_ostream TempOut(Buf);
5727 
5728  printTerminator(TempOut, LO);
5729 
5730  Out << JsonFormat(TempOut.str(), AddQuotes);
5731 }
5732 
5733 // Returns true if by simply looking at the block, we can be sure that it
5734 // results in a sink during analysis. This is useful to know when the analysis
5735 // was interrupted, and we try to figure out if it would sink eventually.
5736 // There may be many more reasons why a sink would appear during analysis
5737 // (eg. checkers may generate sinks arbitrarily), but here we only consider
5738 // sinks that would be obvious by looking at the CFG.
5739 static bool isImmediateSinkBlock(const CFGBlock *Blk) {
5740  if (Blk->hasNoReturnElement())
5741  return true;
5742 
5743  // FIXME: Throw-expressions are currently generating sinks during analysis:
5744  // they're not supported yet, and also often used for actually terminating
5745  // the program. So we should treat them as sinks in this analysis as well,
5746  // at least for now, but once we have better support for exceptions,
5747  // we'd need to carefully handle the case when the throw is being
5748  // immediately caught.
5749  if (std::any_of(Blk->begin(), Blk->end(), [](const CFGElement &Elm) {
5750  if (Optional<CFGStmt> StmtElm = Elm.getAs<CFGStmt>())
5751  if (isa<CXXThrowExpr>(StmtElm->getStmt()))
5752  return true;
5753  return false;
5754  }))
5755  return true;
5756 
5757  return false;
5758 }
5759 
5761  const CFG &Cfg = *getParent();
5762 
5763  const CFGBlock *StartBlk = this;
5764  if (isImmediateSinkBlock(StartBlk))
5765  return true;
5766 
5768  llvm::SmallPtrSet<const CFGBlock *, 32> Visited;
5769 
5770  DFSWorkList.push_back(StartBlk);
5771  while (!DFSWorkList.empty()) {
5772  const CFGBlock *Blk = DFSWorkList.back();
5773  DFSWorkList.pop_back();
5774  Visited.insert(Blk);
5775 
5776  // If at least one path reaches the CFG exit, it means that control is
5777  // returned to the caller. For now, say that we are not sure what
5778  // happens next. If necessary, this can be improved to analyze
5779  // the parent StackFrameContext's call site in a similar manner.
5780  if (Blk == &Cfg.getExit())
5781  return false;
5782 
5783  for (const auto &Succ : Blk->succs()) {
5784  if (const CFGBlock *SuccBlk = Succ.getReachableBlock()) {
5785  if (!isImmediateSinkBlock(SuccBlk) && !Visited.count(SuccBlk)) {
5786  // If the block has reachable child blocks that aren't no-return,
5787  // add them to the worklist.
5788  DFSWorkList.push_back(SuccBlk);
5789  }
5790  }
5791  }
5792  }
5793 
5794  // Nothing reached the exit. It can only mean one thing: there's no return.
5795  return true;
5796 }
5797 
5799  // If the terminator is a temporary dtor or a virtual base, etc, we can't
5800  // retrieve a meaningful condition, bail out.
5801  if (Terminator.getKind() != CFGTerminator::StmtBranch)
5802  return nullptr;
5803 
5804  // Also, if this method was called on a block that doesn't have 2 successors,
5805  // this block doesn't have retrievable condition.
5806  if (succ_size() < 2)
5807  return nullptr;
5808 
5809  auto StmtElem = rbegin()->getAs<CFGStmt>();
5810  if (!StmtElem)
5811  return nullptr;
5812 
5813  const Stmt *Cond = StmtElem->getStmt();
5814  if (isa<ObjCForCollectionStmt>(Cond))
5815  return nullptr;
5816 
5817  // Only ObjCForCollectionStmt is known not to be a non-Expr terminator, hence
5818  // the cast<>.
5819  return cast<Expr>(Cond)->IgnoreParens();
5820 }
5821 
5823  Stmt *Terminator = getTerminatorStmt();
5824  if (!Terminator)
5825  return nullptr;
5826 
5827  Expr *E = nullptr;
5828 
5829  switch (Terminator->getStmtClass()) {
5830  default:
5831  break;
5832 
5833  case Stmt::CXXForRangeStmtClass:
5834  E = cast<CXXForRangeStmt>(Terminator)->getCond();
5835  break;
5836 
5837  case Stmt::ForStmtClass:
5838  E = cast<ForStmt>(Terminator)->getCond();
5839  break;
5840 
5841  case Stmt::WhileStmtClass:
5842  E = cast<WhileStmt>(Terminator)->getCond();
5843  break;
5844 
5845  case Stmt::DoStmtClass:
5846  E = cast<DoStmt>(Terminator)->getCond();
5847  break;
5848 
5849  case Stmt::IfStmtClass:
5850  E = cast<IfStmt>(Terminator)->getCond();
5851  break;
5852 
5853  case Stmt::ChooseExprClass:
5854  E = cast<ChooseExpr>(Terminator)->getCond();
5855  break;
5856 
5857  case Stmt::IndirectGotoStmtClass:
5858  E = cast<IndirectGotoStmt>(Terminator)->getTarget();
5859  break;
5860 
5861  case Stmt::SwitchStmtClass:
5862  E = cast<SwitchStmt>(Terminator)->getCond();
5863  break;
5864 
5865  case Stmt::BinaryConditionalOperatorClass:
5866  E = cast<BinaryConditionalOperator>(Terminator)->getCond();
5867  break;
5868 
5869  case Stmt::ConditionalOperatorClass:
5870  E = cast<ConditionalOperator>(Terminator)->getCond();
5871  break;
5872 
5873  case Stmt::BinaryOperatorClass: // '&&' and '||'
5874  E = cast<BinaryOperator>(Terminator)->getLHS();
5875  break;
5876 
5877  case Stmt::ObjCForCollectionStmtClass:
5878  return Terminator;
5879  }
5880 
5881  if (!StripParens)
5882  return E;
5883 
5884  return E ? E->IgnoreParens() : nullptr;
5885 }
5886 
5887 //===----------------------------------------------------------------------===//
5888 // CFG Graphviz Visualization
5889 //===----------------------------------------------------------------------===//
5890 
5891 #ifndef NDEBUG
5892 static StmtPrinterHelper* GraphHelper;
5893 #endif
5894 
5895 void CFG::viewCFG(const LangOptions &LO) const {
5896 #ifndef NDEBUG
5897  StmtPrinterHelper H(this, LO);
5898  GraphHelper = &H;
5899  llvm::ViewGraph(this,"CFG");
5900  GraphHelper = nullptr;
5901 #endif
5902 }
5903 
5904 namespace llvm {
5905 
5906 template<>
5907 struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits {
5908  DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
5909 
5910  static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) {
5911 #ifndef NDEBUG
5912  std::string OutSStr;
5913  llvm::raw_string_ostream Out(OutSStr);
5914  print_block(Out,Graph, *Node, *GraphHelper, false, false);
5915  std::string& OutStr = Out.str();
5916 
5917  if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
5918 
5919  // Process string output to make it nicer...
5920  for (unsigned i = 0; i != OutStr.length(); ++i)
5921  if (OutStr[i] == '\n') { // Left justify
5922  OutStr[i] = '\\';
5923  OutStr.insert(OutStr.begin()+i+1, 'l');
5924  }
5925 
5926  return OutStr;
5927 #else
5928  return {};
5929 #endif
5930  }
5931 };
5932 
5933 } // namespace llvm
Expr * getInc()
Definition: Stmt.h:2417
unsigned getNumSemanticExprs() const
Definition: Expr.h:5732
const Expr * getSubExpr() const
Definition: Expr.h:933
Stmt * Label
An (optional) label that prefixes the executable statements in the block.
Definition: CFG.h:772
bool isBaseInitializer() const
Determine whether this initializer is initializing a base class.
Definition: DeclCXX.h:2369
Defines the clang::ASTContext interface.
const BlockDecl * getBlockDecl() const
Definition: Expr.h:5560
Represents C++ allocator call.
Definition: CFG.h:245
const CXXDestructorDecl * getDestructor() const
Definition: ExprCXX.h:1261
This represents a GCC inline-assembly statement extension.
Definition: Stmt.h:2852
Represents a function declaration or definition.
Definition: Decl.h:1756
static llvm::iterator_range< used_clauses_child_iterator > used_clauses_children(ArrayRef< OMPClause *> Clauses)
Definition: StmtOpenMP.h:142
Expr * getInit() const
Get the initializer.
Definition: DeclCXX.h:2498
bool Cast(InterpState &S, CodePtr OpPC)
Definition: Interp.h:803
CompoundStmt * getBlock() const
Definition: Stmt.h:3243
A class which contains all the information about a particular captured value.
Definition: Decl.h:3929
pred_iterator pred_end()
Definition: CFG.h:939
A (possibly-)qualified type.
Definition: Type.h:643
bool isBlockPointerType() const
Definition: Type.h:6398
base_class_range bases()
Definition: DeclCXX.h:779
ArrayRef< OMPClause * > clauses()
Definition: StmtOpenMP.h:324
Expr * getCond() const
Definition: Expr.h:4142
static SourceLocation GetEndLoc(Decl *D)
Definition: CFG.cpp:66
AdjacentBlocks::const_iterator const_pred_iterator
Definition: CFG.h:925
iterator beginScopeEndInsert(iterator I, size_t Cnt, BumpVectorContext &C)
Definition: CFG.h:1196
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
const Stmt * getStmt() const
Definition: CFG.h:138
bool operator==(CanQual< T > x, CanQual< U > y)
Expr * getCond()
Definition: Stmt.h:2249
DOTGraphTraits(bool isSimple=false)
Definition: CFG.cpp:5908
ElementList::iterator iterator
Definition: CFG.h:866
succ_iterator succ_begin()
Definition: CFG.h:956
CompoundStmt * getSubStmt()
Definition: Expr.h:3937
Specialize PointerLikeTypeTraits to allow LazyGenerationalUpdatePtr to be placed into a PointerUnion...
Definition: Dominators.h:30
bool isReachable() const
Definition: CFG.h:834
const DeclStmt * getConditionVariableDeclStmt() const
If this ForStmt has a condition variable, return the faux DeclStmt associated with the creation of th...
Definition: Stmt.h:2412
Stmt - This represents one statement.
Definition: Stmt.h:66
bool isStandaloneDirective() const
Returns whether or not this is a Standalone directive.
Definition: StmtOpenMP.cpp:25
FunctionType - C99 6.7.5.3 - Function Declarators.
Definition: Type.h:3393
CXXCatchStmt * getHandler(unsigned i)
Definition: StmtCXX.h:107
CFGBlock & getEntry()
Definition: CFG.h:1316
IfStmt - This represents an if/then/else.
Definition: Stmt.h:1812
QualType getPointeeType() const
If this is a pointer, ObjC object pointer, or block pointer, this returns the respective pointee...
Definition: Type.cpp:518
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:1131
C Language Family Type Representation.
Expr * getBase() const
Definition: Expr.h:2883
void prependScopeBegin(const VarDecl *VD, const Stmt *S, BumpVectorContext &C)
Definition: CFG.h:1126
unsigned getBlockID() const
Definition: CFG.h:1075
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:3439
StringRef P
void appendNewAllocator(CXXNewExpr *NE, BumpVectorContext &C)
Definition: CFG.h:1116
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:6339
void appendLifetimeEnds(VarDecl *VD, Stmt *S, BumpVectorContext &C)
Definition: CFG.h:1155
The base class of the type hierarchy.
Definition: Type.h:1436
Represents Objective-C&#39;s @throw statement.
Definition: StmtObjC.h:332
Represents C++ object destructor generated from a call to delete.
Definition: CFG.h:414
Represents an array type, per C99 6.7.5.2 - Array Declarators.
Definition: Type.h:2850
iterator begin()
Definition: CFG.h:876
Represents a call to a C++ constructor.
Definition: ExprCXX.h:1331
T castAs() const
Convert to the specified CFGElement type, asserting that this CFGElement is of the desired type...
Definition: CFG.h:98
DOTGraphTraits(bool isSimple=false)
unsigned IgnoreDefaultsWithCoveredEnums
Definition: CFG.h:984
Represents a prvalue temporary that is written into memory so that a reference can bind to it...
Definition: ExprCXX.h:4325
float __ovld __cnfn distance(float p0, float p1)
Returns the distance between p0 and p1.
A shortcut around virtual base initializers.
Definition: CFG.h:516
void prependScopeEnd(const VarDecl *VD, const Stmt *S, BumpVectorContext &C)
Definition: CFG.h:1135
bool isCompleteDefinition() const
Return true if this decl has its body fully specified.
Definition: Decl.h:3210
unsigned succ_size() const
Definition: CFG.h:974
const CXXDestructorDecl * getDestructorDecl(ASTContext &astContext) const
Definition: CFG.cpp:4876
Stmt * getSubStmt()
Definition: Stmt.h:1645
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:1928
Represents a variable declaration or definition.
Definition: Decl.h:812
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6857
CFGBlock * getReachableBlock() const
Get the reachable block, if one exists.
Definition: CFG.h:811
const char * getName() const
Definition: Stmt.cpp:351
Stmt * getThen()
Definition: Stmt.h:1899
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:5333
A C++ throw-expression (C++ [except.throw]).
Definition: ExprCXX.h:1049
Represents an expression – generally a full-expression – that introduces cleanups to be run at the ...
Definition: ExprCXX.h:3212
static bool isAssignmentOp(Opcode Opc)
Definition: Expr.h:3530
Defines the clang::Expr interface and subclasses for C++ expressions.
void printTerminatorJson(raw_ostream &Out, const LangOptions &LO, bool AddQuotes) const
printTerminatorJson - Pretty-prints the terminator in JSON format.
Definition: CFG.cpp:5723
const Stmt * getSubStmt() const
Definition: StmtObjC.h:379
Represents a function call that returns a C++ object by value.
Definition: CFG.h:184
LabelStmt - Represents a label, which has a substatement.
Definition: Stmt.h:1710
static TryResult bothKnownTrue(TryResult R1, TryResult R2)
Definition: CFG.cpp:382
bool pred_empty() const
Definition: CFG.h:978
Stmt * getBody()
Definition: Stmt.h:2353
const Stmt * getStructuredBlock() const
Returns the AST node representing OpenMP structured-block of this OpenMP executable directive...
Definition: StmtOpenMP.cpp:36
CFGBlock * getPossiblyUnreachableBlock() const
Get the potentially unreachable block.
Definition: CFG.h:816
void print(raw_ostream &Out, unsigned Indentation=0, bool PrintInstantiation=false) const
DeclStmt * getConditionVariableDeclStmt()
If this SwitchStmt has a condition variable, return the faux DeclStmt associated with the creation of...
Definition: Stmt.h:2134
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:160
void setLoopTarget(const Stmt *loopTarget)
Definition: CFG.h:1042
static std::string getNodeLabel(const CFGBlock *Node, const CFG *Graph)
Definition: CFG.cpp:5910
field_range fields() const
Definition: Decl.h:3849
Represents a member of a struct/union/class.
Definition: Decl.h:2615
TypeSourceInfo * getTypeSourceInfo() const
Returns the declarator information for a base class or delegating initializer.
Definition: DeclCXX.h:2430
iterator insertAutomaticObjDtor(iterator I, VarDecl *VD, Stmt *S)
Definition: CFG.h:1175
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:5716
Represents C++ object destructor implicitly generated for automatic object or temporary bound to cons...
Definition: CFG.h:389
void appendAutomaticObjDtor(VarDecl *VD, Stmt *S, BumpVectorContext &C)
Definition: CFG.h:1151
const CXXRecordDecl * getCXXRecordDecl() const
Definition: CFG.h:419
bool isReferenceType() const
Definition: Type.h:6402
const CXXConstructExpr * getConstructExpr() const
Returns the CXXConstructExpr from this new-expression, or null.
Definition: ExprCXX.h:2193
succ_range succs()
Definition: CFG.h:966
bool isAsmGoto() const
Definition: Stmt.h:2997
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:2171
Expr * getSubExpr()
Definition: Expr.h:3172
void setTerminator(CFGTerminator Term)
Definition: CFG.h:1040
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:1302
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:932
bool isGLValue() const
Definition: Expr.h:261
IndirectGotoStmt - This represents an indirect goto.
Definition: Stmt.h:2494
Describes an C or C++ initializer list.
Definition: Expr.h:4370
BinaryOperatorKind
Optional< Expr * > getArraySize()
Definition: ExprCXX.h:2131
std::string JsonFormat(StringRef RawSR, bool AddQuotes)
Definition: JsonSupport.h:27
Kind getKind() const
Definition: CFG.h:537
ForStmt - This represents a &#39;for (init;cond;inc)&#39; stmt.
Definition: Stmt.h:2384
APValue Val
Val - This is the value the expression can be folded to.
Definition: Expr.h:582
LabelDecl * getDecl() const
Definition: Stmt.h:1727
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:1872
Expr * getInitializer()
The initializer of this new-expression.
Definition: ExprCXX.h:2181
Stmt * getBody()
Definition: Stmt.h:2418
CFGCallback * Observer
Definition: CFG.h:1238
child_range children()
Definition: Stmt.cpp:223
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:1620
A builtin binary operation expression such as "x + y" or "x <= y".
Definition: Expr.h:3404
Stmt * getInit()
Definition: Stmt.h:2397
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:5708
bool isLinear() const
Returns true if the CFG has no branches.
Definition: CFG.cpp:4830
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:6148
const VarDecl * getVarDecl() const
Definition: CFG.h:394
CaseStmt - Represent a case statement.
Definition: Stmt.h:1478
void appendLoopExit(const Stmt *LoopStmt, BumpVectorContext &C)
Definition: CFG.h:1159
Expr * getCond()
Definition: Stmt.h:2416
bool isInt() const
Definition: APValue.h:317
CastExpr - Base class for type casts, including both implicit casts (ImplicitCastExpr) and explicit c...
Definition: Expr.h:3120
Represents binding an expression to a temporary.
Definition: ExprCXX.h:1282
CXXTemporary * getTemporary()
Definition: ExprCXX.h:1301
FieldDecl * getAnyMember() const
Definition: DeclCXX.h:2442
A C++ lambda expression, which produces a function object (of unspecified type) that can be invoked l...
Definition: ExprCXX.h:1727
bool hasTrivialDestructor() const
Determine whether this class has a trivial destructor (C++ [class.dtor]p3)
Definition: DeclCXX.h:1445
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:1425
CXXDestructorDecl * getDestructor() const
Returns the destructor decl for this class.
Definition: DeclCXX.cpp:1735
VarDecl * getConditionVariable() const
Retrieve the variable declared in this "for" statement, if any.
Definition: Stmt.cpp:924
bool getNoReturn() const
Definition: Type.h:3550
Stmt * getBody()
Definition: Stmt.h:2089
Stmt * getInit()
Definition: Stmt.h:1955
arg_iterator placement_arg_end()
Definition: ExprCXX.h:2222
llvm::DenseMap< const Stmt *, const CFGBlock * > ForcedBlkExprs
Definition: CFG.h:1235
CFGBlockListTy::const_iterator const_iterator
Definition: CFG.h:1294
CFG * getParent() const
Definition: CFG.h:1077
CXXCtorInitializer * getInitializer() const
Definition: CFG.h:230
void appendConstructor(CXXConstructExpr *CE, const ConstructionContext *CC, BumpVectorContext &C)
Definition: CFG.h:1100
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:1649
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3725
bool isDelegatingInitializer() const
Determine whether this initializer is creating a delegating constructor.
Definition: DeclCXX.h:2397
UnaryExprOrTypeTraitExpr - expression with either a type or (unevaluated) expression operand...
Definition: Expr.h:2342
void appendBaseDtor(const CXXBaseSpecifier *BS, BumpVectorContext &C)
Definition: CFG.h:1139
static bool shouldAddCase(bool &switchExclusivelyCovered, const Expr::EvalResult *switchCond, const CaseStmt *CS, ASTContext &Ctx)
Definition: CFG.cpp:4032
Represents a single basic block in a source-level CFG.
Definition: CFG.h:576
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.
const VarDecl * getVarDecl() const
Definition: CFG.h:327
This represents one expression.
Definition: Expr.h:108
Defines the clang::LangOptions interface.
Stmt * getTerminatorCondition(bool StripParens=true)
Definition: CFG.cpp:5822
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
Represents a source-level, intra-procedural CFG that represents the control-flow of a Stmt...
Definition: CFG.h:1225
void dumpToStream(llvm::raw_ostream &OS) const
Definition: CFG.cpp:5328
const Expr * getLastCondition() const
Definition: CFG.cpp:5798
Represents a C++ functional cast expression that builds a temporary object.
Definition: ExprCXX.h:1659
BlockExpr - Adaptor class for mixing a BlockDecl with expressions.
Definition: Expr.h:5546
Represents a C++ destructor within a class.
Definition: DeclCXX.h:2792
bool succ_empty() const
Definition: CFG.h:975
VarDecl * getExceptionDecl() const
Definition: StmtCXX.h:49
Expr * getCallee()
Definition: Expr.h:2633
unsigned getNumInits() const
Definition: Expr.h:4400
Represents C++ constructor call.
Definition: CFG.h:156
QualType getArgumentType() const
Definition: Expr.h:2379
#define bool
Definition: stdbool.h:15
Stmt * getBody()
Definition: Stmt.h:2261
const CompoundStmt * getSynchBody() const
Definition: StmtObjC.h:297
ElementList::const_iterator const_iterator
Definition: CFG.h:867
Expr * getRHS()
Definition: Stmt.h:1579
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:2651
const AstTypeMatcher< ArrayType > arrayType
Matches all kinds of arrays.