clang  7.0.0svn
CFG.cpp
Go to the documentation of this file.
1 //===- CFG.cpp - Classes for representing and building CFGs ---------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines the CFG and CFGBuilder classes for representing and
11 // building Control-Flow Graphs (CFGs) from ASTs.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "clang/Analysis/CFG.h"
16 #include "clang/AST/ASTContext.h"
17 #include "clang/AST/Attr.h"
18 #include "clang/AST/Decl.h"
19 #include "clang/AST/DeclBase.h"
20 #include "clang/AST/DeclCXX.h"
21 #include "clang/AST/DeclGroup.h"
22 #include "clang/AST/Expr.h"
23 #include "clang/AST/ExprCXX.h"
26 #include "clang/AST/Stmt.h"
27 #include "clang/AST/StmtCXX.h"
28 #include "clang/AST/StmtObjC.h"
29 #include "clang/AST/StmtVisitor.h"
30 #include "clang/AST/Type.h"
32 #include "clang/Basic/Builtins.h"
34 #include "clang/Basic/LLVM.h"
37 #include "clang/Basic/Specifiers.h"
38 #include "llvm/ADT/APInt.h"
39 #include "llvm/ADT/APSInt.h"
40 #include "llvm/ADT/ArrayRef.h"
41 #include "llvm/ADT/DenseMap.h"
42 #include "llvm/ADT/Optional.h"
43 #include "llvm/ADT/STLExtras.h"
44 #include "llvm/ADT/SetVector.h"
45 #include "llvm/ADT/SmallPtrSet.h"
46 #include "llvm/ADT/SmallVector.h"
47 #include "llvm/Support/Allocator.h"
48 #include "llvm/Support/Casting.h"
49 #include "llvm/Support/Compiler.h"
50 #include "llvm/Support/DOTGraphTraits.h"
51 #include "llvm/Support/ErrorHandling.h"
52 #include "llvm/Support/Format.h"
53 #include "llvm/Support/GraphWriter.h"
54 #include "llvm/Support/SaveAndRestore.h"
55 #include "llvm/Support/raw_ostream.h"
56 #include <cassert>
57 #include <memory>
58 #include <string>
59 #include <tuple>
60 #include <utility>
61 #include <vector>
62 
63 using namespace clang;
64 
66  if (VarDecl *VD = dyn_cast<VarDecl>(D))
67  if (Expr *Ex = VD->getInit())
68  return Ex->getSourceRange().getEnd();
69  return D->getLocation();
70 }
71 
72 /// Helper for tryNormalizeBinaryOperator. Attempts to extract an IntegerLiteral
73 /// or EnumConstantDecl from the given Expr. If it fails, returns nullptr.
74 static const Expr *tryTransformToIntOrEnumConstant(const Expr *E) {
75  E = E->IgnoreParens();
76  if (isa<IntegerLiteral>(E))
77  return E;
78  if (auto *DR = dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))
79  return isa<EnumConstantDecl>(DR->getDecl()) ? DR : nullptr;
80  return nullptr;
81 }
82 
83 /// Tries to interpret a binary operator into `Decl Op Expr` form, if Expr is
84 /// an integer literal or an enum constant.
85 ///
86 /// If this fails, at least one of the returned DeclRefExpr or Expr will be
87 /// null.
88 static std::tuple<const DeclRefExpr *, BinaryOperatorKind, const Expr *>
90  BinaryOperatorKind Op = B->getOpcode();
91 
92  const Expr *MaybeDecl = B->getLHS();
93  const Expr *Constant = tryTransformToIntOrEnumConstant(B->getRHS());
94  // Expr looked like `0 == Foo` instead of `Foo == 0`
95  if (Constant == nullptr) {
96  // Flip the operator
97  if (Op == BO_GT)
98  Op = BO_LT;
99  else if (Op == BO_GE)
100  Op = BO_LE;
101  else if (Op == BO_LT)
102  Op = BO_GT;
103  else if (Op == BO_LE)
104  Op = BO_GE;
105 
106  MaybeDecl = B->getRHS();
107  Constant = tryTransformToIntOrEnumConstant(B->getLHS());
108  }
109 
110  auto *D = dyn_cast<DeclRefExpr>(MaybeDecl->IgnoreParenImpCasts());
111  return std::make_tuple(D, Op, Constant);
112 }
113 
114 /// For an expression `x == Foo && x == Bar`, this determines whether the
115 /// `Foo` and `Bar` are either of the same enumeration type, or both integer
116 /// literals.
117 ///
118 /// It's an error to pass this arguments that are not either IntegerLiterals
119 /// or DeclRefExprs (that have decls of type EnumConstantDecl)
120 static bool areExprTypesCompatible(const Expr *E1, const Expr *E2) {
121  // User intent isn't clear if they're mixing int literals with enum
122  // constants.
123  if (isa<IntegerLiteral>(E1) != isa<IntegerLiteral>(E2))
124  return false;
125 
126  // Integer literal comparisons, regardless of literal type, are acceptable.
127  if (isa<IntegerLiteral>(E1))
128  return true;
129 
130  // IntegerLiterals are handled above and only EnumConstantDecls are expected
131  // beyond this point
132  assert(isa<DeclRefExpr>(E1) && isa<DeclRefExpr>(E2));
133  auto *Decl1 = cast<DeclRefExpr>(E1)->getDecl();
134  auto *Decl2 = cast<DeclRefExpr>(E2)->getDecl();
135 
136  assert(isa<EnumConstantDecl>(Decl1) && isa<EnumConstantDecl>(Decl2));
137  const DeclContext *DC1 = Decl1->getDeclContext();
138  const DeclContext *DC2 = Decl2->getDeclContext();
139 
140  assert(isa<EnumDecl>(DC1) && isa<EnumDecl>(DC2));
141  return DC1 == DC2;
142 }
143 
144 namespace {
145 
146 class CFGBuilder;
147 
148 /// The CFG builder uses a recursive algorithm to build the CFG. When
149 /// we process an expression, sometimes we know that we must add the
150 /// subexpressions as block-level expressions. For example:
151 ///
152 /// exp1 || exp2
153 ///
154 /// When processing the '||' expression, we know that exp1 and exp2
155 /// need to be added as block-level expressions, even though they
156 /// might not normally need to be. AddStmtChoice records this
157 /// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then
158 /// the builder has an option not to add a subexpression as a
159 /// block-level expression.
160 class AddStmtChoice {
161 public:
162  enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 };
163 
164  AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {}
165 
166  bool alwaysAdd(CFGBuilder &builder,
167  const Stmt *stmt) const;
168 
169  /// Return a copy of this object, except with the 'always-add' bit
170  /// set as specified.
171  AddStmtChoice withAlwaysAdd(bool alwaysAdd) const {
172  return AddStmtChoice(alwaysAdd ? AlwaysAdd : NotAlwaysAdd);
173  }
174 
175 private:
176  Kind kind;
177 };
178 
179 /// LocalScope - Node in tree of local scopes created for C++ implicit
180 /// destructor calls generation. It contains list of automatic variables
181 /// declared in the scope and link to position in previous scope this scope
182 /// began in.
183 ///
184 /// The process of creating local scopes is as follows:
185 /// - Init CFGBuilder::ScopePos with invalid position (equivalent for null),
186 /// - Before processing statements in scope (e.g. CompoundStmt) create
187 /// LocalScope object using CFGBuilder::ScopePos as link to previous scope
188 /// and set CFGBuilder::ScopePos to the end of new scope,
189 /// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points
190 /// at this VarDecl,
191 /// - For every normal (without jump) end of scope add to CFGBlock destructors
192 /// for objects in the current scope,
193 /// - For every jump add to CFGBlock destructors for objects
194 /// between CFGBuilder::ScopePos and local scope position saved for jump
195 /// target. Thanks to C++ restrictions on goto jumps we can be sure that
196 /// jump target position will be on the path to root from CFGBuilder::ScopePos
197 /// (adding any variable that doesn't need constructor to be called to
198 /// LocalScope can break this assumption),
199 ///
200 class LocalScope {
201 public:
202  friend class const_iterator;
203 
204  using AutomaticVarsTy = BumpVector<VarDecl *>;
205 
206  /// const_iterator - Iterates local scope backwards and jumps to previous
207  /// scope on reaching the beginning of currently iterated scope.
208  class const_iterator {
209  const LocalScope* Scope = nullptr;
210 
211  /// VarIter is guaranteed to be greater then 0 for every valid iterator.
212  /// Invalid iterator (with null Scope) has VarIter equal to 0.
213  unsigned VarIter = 0;
214 
215  public:
216  /// Create invalid iterator. Dereferencing invalid iterator is not allowed.
217  /// Incrementing invalid iterator is allowed and will result in invalid
218  /// iterator.
219  const_iterator() = default;
220 
221  /// Create valid iterator. In case when S.Prev is an invalid iterator and
222  /// I is equal to 0, this will create invalid iterator.
223  const_iterator(const LocalScope& S, unsigned I)
224  : Scope(&S), VarIter(I) {
225  // Iterator to "end" of scope is not allowed. Handle it by going up
226  // in scopes tree possibly up to invalid iterator in the root.
227  if (VarIter == 0 && Scope)
228  *this = Scope->Prev;
229  }
230 
231  VarDecl *const* operator->() const {
232  assert(Scope && "Dereferencing invalid iterator is not allowed");
233  assert(VarIter != 0 && "Iterator has invalid value of VarIter member");
234  return &Scope->Vars[VarIter - 1];
235  }
236  VarDecl *operator*() const {
237  return *this->operator->();
238  }
239 
240  const_iterator &operator++() {
241  if (!Scope)
242  return *this;
243 
244  assert(VarIter != 0 && "Iterator has invalid value of VarIter member");
245  --VarIter;
246  if (VarIter == 0)
247  *this = Scope->Prev;
248  return *this;
249  }
250  const_iterator operator++(int) {
251  const_iterator P = *this;
252  ++*this;
253  return P;
254  }
255 
256  bool operator==(const const_iterator &rhs) const {
257  return Scope == rhs.Scope && VarIter == rhs.VarIter;
258  }
259  bool operator!=(const const_iterator &rhs) const {
260  return !(*this == rhs);
261  }
262 
263  explicit operator bool() const {
264  return *this != const_iterator();
265  }
266 
267  int distance(const_iterator L);
268  const_iterator shared_parent(const_iterator L);
269  };
270 
271 private:
272  BumpVectorContext ctx;
273 
274  /// Automatic variables in order of declaration.
275  AutomaticVarsTy Vars;
276 
277  /// Iterator to variable in previous scope that was declared just before
278  /// begin of this scope.
279  const_iterator Prev;
280 
281 public:
282  /// Constructs empty scope linked to previous scope in specified place.
283  LocalScope(BumpVectorContext ctx, const_iterator P)
284  : ctx(std::move(ctx)), Vars(this->ctx, 4), Prev(P) {}
285 
286  /// Begin of scope in direction of CFG building (backwards).
287  const_iterator begin() const { return const_iterator(*this, Vars.size()); }
288 
289  void addVar(VarDecl *VD) {
290  Vars.push_back(VD, ctx);
291  }
292 };
293 
294 } // namespace
295 
296 /// distance - Calculates distance from this to L. L must be reachable from this
297 /// (with use of ++ operator). Cost of calculating the distance is linear w.r.t.
298 /// number of scopes between this and L.
299 int LocalScope::const_iterator::distance(LocalScope::const_iterator L) {
300  int D = 0;
301  const_iterator F = *this;
302  while (F.Scope != L.Scope) {
303  assert(F != const_iterator() &&
304  "L iterator is not reachable from F iterator.");
305  D += F.VarIter;
306  F = F.Scope->Prev;
307  }
308  D += F.VarIter - L.VarIter;
309  return D;
310 }
311 
312 /// Calculates the closest parent of this iterator
313 /// that is in a scope reachable through the parents of L.
314 /// I.e. when using 'goto' from this to L, the lifetime of all variables
315 /// between this and shared_parent(L) end.
316 LocalScope::const_iterator
317 LocalScope::const_iterator::shared_parent(LocalScope::const_iterator L) {
318  llvm::SmallPtrSet<const LocalScope *, 4> ScopesOfL;
319  while (true) {
320  ScopesOfL.insert(L.Scope);
321  if (L == const_iterator())
322  break;
323  L = L.Scope->Prev;
324  }
325 
326  const_iterator F = *this;
327  while (true) {
328  if (ScopesOfL.count(F.Scope))
329  return F;
330  assert(F != const_iterator() &&
331  "L iterator is not reachable from F iterator.");
332  F = F.Scope->Prev;
333  }
334 }
335 
336 namespace {
337 
338 /// Structure for specifying position in CFG during its build process. It
339 /// consists of CFGBlock that specifies position in CFG and
340 /// LocalScope::const_iterator that specifies position in LocalScope graph.
341 struct BlockScopePosPair {
342  CFGBlock *block = nullptr;
343  LocalScope::const_iterator scopePosition;
344 
345  BlockScopePosPair() = default;
346  BlockScopePosPair(CFGBlock *b, LocalScope::const_iterator scopePos)
347  : block(b), scopePosition(scopePos) {}
348 };
349 
350 /// TryResult - a class representing a variant over the values
351 /// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool,
352 /// and is used by the CFGBuilder to decide if a branch condition
353 /// can be decided up front during CFG construction.
354 class TryResult {
355  int X = -1;
356 
357 public:
358  TryResult() = default;
359  TryResult(bool b) : X(b ? 1 : 0) {}
360 
361  bool isTrue() const { return X == 1; }
362  bool isFalse() const { return X == 0; }
363  bool isKnown() const { return X >= 0; }
364 
365  void negate() {
366  assert(isKnown());
367  X ^= 0x1;
368  }
369 };
370 
371 } // namespace
372 
373 static TryResult bothKnownTrue(TryResult R1, TryResult R2) {
374  if (!R1.isKnown() || !R2.isKnown())
375  return TryResult();
376  return TryResult(R1.isTrue() && R2.isTrue());
377 }
378 
379 namespace {
380 
381 class reverse_children {
382  llvm::SmallVector<Stmt *, 12> childrenBuf;
384 
385 public:
386  reverse_children(Stmt *S);
387 
388  using iterator = ArrayRef<Stmt *>::reverse_iterator;
389 
390  iterator begin() const { return children.rbegin(); }
391  iterator end() const { return children.rend(); }
392 };
393 
394 } // namespace
395 
396 reverse_children::reverse_children(Stmt *S) {
397  if (CallExpr *CE = dyn_cast<CallExpr>(S)) {
398  children = CE->getRawSubExprs();
399  return;
400  }
401  switch (S->getStmtClass()) {
402  // Note: Fill in this switch with more cases we want to optimize.
403  case Stmt::InitListExprClass: {
404  InitListExpr *IE = cast<InitListExpr>(S);
405  children = llvm::makeArrayRef(reinterpret_cast<Stmt**>(IE->getInits()),
406  IE->getNumInits());
407  return;
408  }
409  default:
410  break;
411  }
412 
413  // Default case for all other statements.
414  for (Stmt *SubStmt : S->children())
415  childrenBuf.push_back(SubStmt);
416 
417  // This needs to be done *after* childrenBuf has been populated.
418  children = childrenBuf;
419 }
420 
421 namespace {
422 
423 /// CFGBuilder - This class implements CFG construction from an AST.
424 /// The builder is stateful: an instance of the builder should be used to only
425 /// construct a single CFG.
426 ///
427 /// Example usage:
428 ///
429 /// CFGBuilder builder;
430 /// std::unique_ptr<CFG> cfg = builder.buildCFG(decl, stmt1);
431 ///
432 /// CFG construction is done via a recursive walk of an AST. We actually parse
433 /// the AST in reverse order so that the successor of a basic block is
434 /// constructed prior to its predecessor. This allows us to nicely capture
435 /// implicit fall-throughs without extra basic blocks.
436 class CFGBuilder {
437  using JumpTarget = BlockScopePosPair;
438  using JumpSource = BlockScopePosPair;
439 
440  ASTContext *Context;
441  std::unique_ptr<CFG> cfg;
442 
443  // Current block.
444  CFGBlock *Block = nullptr;
445 
446  // Block after the current block.
447  CFGBlock *Succ = nullptr;
448 
449  JumpTarget ContinueJumpTarget;
450  JumpTarget BreakJumpTarget;
451  JumpTarget SEHLeaveJumpTarget;
452  CFGBlock *SwitchTerminatedBlock = nullptr;
453  CFGBlock *DefaultCaseBlock = nullptr;
454 
455  // This can point either to a try or a __try block. The frontend forbids
456  // mixing both kinds in one function, so having one for both is enough.
457  CFGBlock *TryTerminatedBlock = nullptr;
458 
459  // Current position in local scope.
460  LocalScope::const_iterator ScopePos;
461 
462  // LabelMap records the mapping from Label expressions to their jump targets.
463  using LabelMapTy = llvm::DenseMap<LabelDecl *, JumpTarget>;
464  LabelMapTy LabelMap;
465 
466  // A list of blocks that end with a "goto" that must be backpatched to their
467  // resolved targets upon completion of CFG construction.
468  using BackpatchBlocksTy = std::vector<JumpSource>;
469  BackpatchBlocksTy BackpatchBlocks;
470 
471  // A list of labels whose address has been taken (for indirect gotos).
472  using LabelSetTy = llvm::SmallSetVector<LabelDecl *, 8>;
473  LabelSetTy AddressTakenLabels;
474 
475  // Information about the currently visited C++ object construction site.
476  // This is set in the construction trigger and read when the constructor
477  // itself is being visited.
478  ConstructionContext CurrentConstructionContext = {};
479 
480  bool badCFG = false;
481  const CFG::BuildOptions &BuildOpts;
482 
483  // State to track for building switch statements.
484  bool switchExclusivelyCovered = false;
485  Expr::EvalResult *switchCond = nullptr;
486 
487  CFG::BuildOptions::ForcedBlkExprs::value_type *cachedEntry = nullptr;
488  const Stmt *lastLookup = nullptr;
489 
490  // Caches boolean evaluations of expressions to avoid multiple re-evaluations
491  // during construction of branches for chained logical operators.
492  using CachedBoolEvalsTy = llvm::DenseMap<Expr *, TryResult>;
493  CachedBoolEvalsTy CachedBoolEvals;
494 
495 public:
496  explicit CFGBuilder(ASTContext *astContext,
497  const CFG::BuildOptions &buildOpts)
498  : Context(astContext), cfg(new CFG()), // crew a new CFG
499  BuildOpts(buildOpts) {}
500 
501  // buildCFG - Used by external clients to construct the CFG.
502  std::unique_ptr<CFG> buildCFG(const Decl *D, Stmt *Statement);
503 
504  bool alwaysAdd(const Stmt *stmt);
505 
506 private:
507  // Visitors to walk an AST and construct the CFG.
508  CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc);
509  CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc);
510  CFGBlock *VisitBreakStmt(BreakStmt *B);
511  CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc);
512  CFGBlock *VisitCaseStmt(CaseStmt *C);
513  CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc);
514  CFGBlock *VisitCompoundStmt(CompoundStmt *C);
515  CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C,
516  AddStmtChoice asc);
517  CFGBlock *VisitContinueStmt(ContinueStmt *C);
518  CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
519  AddStmtChoice asc);
520  CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S);
521  CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc);
522  CFGBlock *VisitCXXNewExpr(CXXNewExpr *DE, AddStmtChoice asc);
523  CFGBlock *VisitCXXDeleteExpr(CXXDeleteExpr *DE, AddStmtChoice asc);
524  CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S);
525  CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
526  AddStmtChoice asc);
527  CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
528  AddStmtChoice asc);
529  CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T);
530  CFGBlock *VisitCXXTryStmt(CXXTryStmt *S);
531  CFGBlock *VisitDeclStmt(DeclStmt *DS);
532  CFGBlock *VisitDeclSubExpr(DeclStmt *DS);
533  CFGBlock *VisitDefaultStmt(DefaultStmt *D);
534  CFGBlock *VisitDoStmt(DoStmt *D);
535  CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, AddStmtChoice asc);
536  CFGBlock *VisitForStmt(ForStmt *F);
537  CFGBlock *VisitGotoStmt(GotoStmt *G);
538  CFGBlock *VisitIfStmt(IfStmt *I);
539  CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc);
540  CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I);
541  CFGBlock *VisitLabelStmt(LabelStmt *L);
542  CFGBlock *VisitBlockExpr(BlockExpr *E, AddStmtChoice asc);
543  CFGBlock *VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc);
544  CFGBlock *VisitLogicalOperator(BinaryOperator *B);
545  std::pair<CFGBlock *, CFGBlock *> VisitLogicalOperator(BinaryOperator *B,
546  Stmt *Term,
547  CFGBlock *TrueBlock,
548  CFGBlock *FalseBlock);
549  CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc);
550  CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S);
551  CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S);
552  CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S);
553  CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S);
554  CFGBlock *VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S);
555  CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S);
556  CFGBlock *VisitPseudoObjectExpr(PseudoObjectExpr *E);
557  CFGBlock *VisitReturnStmt(ReturnStmt *R);
558  CFGBlock *VisitSEHExceptStmt(SEHExceptStmt *S);
559  CFGBlock *VisitSEHFinallyStmt(SEHFinallyStmt *S);
560  CFGBlock *VisitSEHLeaveStmt(SEHLeaveStmt *S);
561  CFGBlock *VisitSEHTryStmt(SEHTryStmt *S);
562  CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc);
563  CFGBlock *VisitSwitchStmt(SwitchStmt *S);
564  CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
565  AddStmtChoice asc);
566  CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc);
567  CFGBlock *VisitWhileStmt(WhileStmt *W);
568 
569  CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd);
570  CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc);
571  CFGBlock *VisitChildren(Stmt *S);
572  CFGBlock *VisitNoRecurse(Expr *E, AddStmtChoice asc);
573 
574  /// When creating the CFG for temporary destructors, we want to mirror the
575  /// branch structure of the corresponding constructor calls.
576  /// Thus, while visiting a statement for temporary destructors, we keep a
577  /// context to keep track of the following information:
578  /// - whether a subexpression is executed unconditionally
579  /// - if a subexpression is executed conditionally, the first
580  /// CXXBindTemporaryExpr we encounter in that subexpression (which
581  /// corresponds to the last temporary destructor we have to call for this
582  /// subexpression) and the CFG block at that point (which will become the
583  /// successor block when inserting the decision point).
584  ///
585  /// That way, we can build the branch structure for temporary destructors as
586  /// follows:
587  /// 1. If a subexpression is executed unconditionally, we add the temporary
588  /// destructor calls to the current block.
589  /// 2. If a subexpression is executed conditionally, when we encounter a
590  /// CXXBindTemporaryExpr:
591  /// a) If it is the first temporary destructor call in the subexpression,
592  /// we remember the CXXBindTemporaryExpr and the current block in the
593  /// TempDtorContext; we start a new block, and insert the temporary
594  /// destructor call.
595  /// b) Otherwise, add the temporary destructor call to the current block.
596  /// 3. When we finished visiting a conditionally executed subexpression,
597  /// and we found at least one temporary constructor during the visitation
598  /// (2.a has executed), we insert a decision block that uses the
599  /// CXXBindTemporaryExpr as terminator, and branches to the current block
600  /// if the CXXBindTemporaryExpr was marked executed, and otherwise
601  /// branches to the stored successor.
602  struct TempDtorContext {
603  TempDtorContext() = default;
604  TempDtorContext(TryResult KnownExecuted)
605  : IsConditional(true), KnownExecuted(KnownExecuted) {}
606 
607  /// Returns whether we need to start a new branch for a temporary destructor
608  /// call. This is the case when the temporary destructor is
609  /// conditionally executed, and it is the first one we encounter while
610  /// visiting a subexpression - other temporary destructors at the same level
611  /// will be added to the same block and are executed under the same
612  /// condition.
613  bool needsTempDtorBranch() const {
614  return IsConditional && !TerminatorExpr;
615  }
616 
617  /// Remember the successor S of a temporary destructor decision branch for
618  /// the corresponding CXXBindTemporaryExpr E.
619  void setDecisionPoint(CFGBlock *S, CXXBindTemporaryExpr *E) {
620  Succ = S;
621  TerminatorExpr = E;
622  }
623 
624  const bool IsConditional = false;
625  const TryResult KnownExecuted = true;
626  CFGBlock *Succ = nullptr;
627  CXXBindTemporaryExpr *TerminatorExpr = nullptr;
628  };
629 
630  // Visitors to walk an AST and generate destructors of temporaries in
631  // full expression.
632  CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary,
633  TempDtorContext &Context);
634  CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E, TempDtorContext &Context);
635  CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E,
636  TempDtorContext &Context);
637  CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(
638  CXXBindTemporaryExpr *E, bool BindToTemporary, TempDtorContext &Context);
639  CFGBlock *VisitConditionalOperatorForTemporaryDtors(
640  AbstractConditionalOperator *E, bool BindToTemporary,
641  TempDtorContext &Context);
642  void InsertTempDtorDecisionBlock(const TempDtorContext &Context,
643  CFGBlock *FalseSucc = nullptr);
644 
645  // NYS == Not Yet Supported
646  CFGBlock *NYS() {
647  badCFG = true;
648  return Block;
649  }
650 
651  // Scan the child statement \p Child to find the constructor that might
652  // have been directly triggered by the current node, \p Trigger. If such
653  // constructor has been found, set current construction context to point
654  // to the trigger statement. The construction context will be unset once
655  // it is consumed when the CFG building procedure processes the
656  // construct-expression and adds the respective CFGConstructor element.
657  void EnterConstructionContextIfNecessary(
658  ConstructionContext::TriggerTy Trigger, Stmt *Child);
659  // Unset the construction context after consuming it. This is done immediately
660  // after adding the CFGConstructor element, so there's no need to
661  // do this manually in every Visit... function.
662  void ExitConstructionContext();
663 
664  void autoCreateBlock() { if (!Block) Block = createBlock(); }
665  CFGBlock *createBlock(bool add_successor = true);
666  CFGBlock *createNoReturnBlock();
667 
668  CFGBlock *addStmt(Stmt *S) {
669  return Visit(S, AddStmtChoice::AlwaysAdd);
670  }
671 
672  CFGBlock *addInitializer(CXXCtorInitializer *I);
673  void addLoopExit(const Stmt *LoopStmt);
674  void addAutomaticObjDtors(LocalScope::const_iterator B,
675  LocalScope::const_iterator E, Stmt *S);
676  void addLifetimeEnds(LocalScope::const_iterator B,
677  LocalScope::const_iterator E, Stmt *S);
678  void addAutomaticObjHandling(LocalScope::const_iterator B,
679  LocalScope::const_iterator E, Stmt *S);
680  void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD);
681 
682  // Local scopes creation.
683  LocalScope* createOrReuseLocalScope(LocalScope* Scope);
684 
685  void addLocalScopeForStmt(Stmt *S);
686  LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS,
687  LocalScope* Scope = nullptr);
688  LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = nullptr);
689 
690  void addLocalScopeAndDtors(Stmt *S);
691 
692  // Interface to CFGBlock - adding CFGElements.
693 
694  void appendStmt(CFGBlock *B, const Stmt *S) {
695  if (alwaysAdd(S) && cachedEntry)
696  cachedEntry->second = B;
697 
698  // All block-level expressions should have already been IgnoreParens()ed.
699  assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S);
700  B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext());
701  }
702 
703  void appendConstructor(CFGBlock *B, CXXConstructExpr *CE) {
704  if (BuildOpts.AddRichCXXConstructors) {
705  if (!CurrentConstructionContext.isNull()) {
706  B->appendConstructor(CE, CurrentConstructionContext,
707  cfg->getBumpVectorContext());
708  ExitConstructionContext();
709  return;
710  }
711  }
712 
713  // No valid construction context found. Fall back to statement.
714  B->appendStmt(CE, cfg->getBumpVectorContext());
715  }
716 
717  void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) {
718  B->appendInitializer(I, cfg->getBumpVectorContext());
719  }
720 
721  void appendNewAllocator(CFGBlock *B, CXXNewExpr *NE) {
722  B->appendNewAllocator(NE, cfg->getBumpVectorContext());
723  }
724 
725  void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) {
726  B->appendBaseDtor(BS, cfg->getBumpVectorContext());
727  }
728 
729  void appendMemberDtor(CFGBlock *B, FieldDecl *FD) {
730  B->appendMemberDtor(FD, cfg->getBumpVectorContext());
731  }
732 
733  void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) {
734  B->appendTemporaryDtor(E, cfg->getBumpVectorContext());
735  }
736 
737  void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) {
738  B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext());
739  }
740 
741  void appendLifetimeEnds(CFGBlock *B, VarDecl *VD, Stmt *S) {
742  B->appendLifetimeEnds(VD, S, cfg->getBumpVectorContext());
743  }
744 
745  void appendLoopExit(CFGBlock *B, const Stmt *LoopStmt) {
746  B->appendLoopExit(LoopStmt, cfg->getBumpVectorContext());
747  }
748 
749  void appendDeleteDtor(CFGBlock *B, CXXRecordDecl *RD, CXXDeleteExpr *DE) {
750  B->appendDeleteDtor(RD, DE, cfg->getBumpVectorContext());
751  }
752 
753  void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
754  LocalScope::const_iterator B, LocalScope::const_iterator E);
755 
756  void prependAutomaticObjLifetimeWithTerminator(CFGBlock *Blk,
757  LocalScope::const_iterator B,
758  LocalScope::const_iterator E);
759 
760  void addSuccessor(CFGBlock *B, CFGBlock *S, bool IsReachable = true) {
761  B->addSuccessor(CFGBlock::AdjacentBlock(S, IsReachable),
762  cfg->getBumpVectorContext());
763  }
764 
765  /// Add a reachable successor to a block, with the alternate variant that is
766  /// unreachable.
767  void addSuccessor(CFGBlock *B, CFGBlock *ReachableBlock, CFGBlock *AltBlock) {
768  B->addSuccessor(CFGBlock::AdjacentBlock(ReachableBlock, AltBlock),
769  cfg->getBumpVectorContext());
770  }
771 
772  /// \brief Find a relational comparison with an expression evaluating to a
773  /// boolean and a constant other than 0 and 1.
774  /// e.g. if ((x < y) == 10)
775  TryResult checkIncorrectRelationalOperator(const BinaryOperator *B) {
776  const Expr *LHSExpr = B->getLHS()->IgnoreParens();
777  const Expr *RHSExpr = B->getRHS()->IgnoreParens();
778 
779  const IntegerLiteral *IntLiteral = dyn_cast<IntegerLiteral>(LHSExpr);
780  const Expr *BoolExpr = RHSExpr;
781  bool IntFirst = true;
782  if (!IntLiteral) {
783  IntLiteral = dyn_cast<IntegerLiteral>(RHSExpr);
784  BoolExpr = LHSExpr;
785  IntFirst = false;
786  }
787 
788  if (!IntLiteral || !BoolExpr->isKnownToHaveBooleanValue())
789  return TryResult();
790 
791  llvm::APInt IntValue = IntLiteral->getValue();
792  if ((IntValue == 1) || (IntValue == 0))
793  return TryResult();
794 
795  bool IntLarger = IntLiteral->getType()->isUnsignedIntegerType() ||
796  !IntValue.isNegative();
797 
798  BinaryOperatorKind Bok = B->getOpcode();
799  if (Bok == BO_GT || Bok == BO_GE) {
800  // Always true for 10 > bool and bool > -1
801  // Always false for -1 > bool and bool > 10
802  return TryResult(IntFirst == IntLarger);
803  } else {
804  // Always true for -1 < bool and bool < 10
805  // Always false for 10 < bool and bool < -1
806  return TryResult(IntFirst != IntLarger);
807  }
808  }
809 
810  /// Find an incorrect equality comparison. Either with an expression
811  /// evaluating to a boolean and a constant other than 0 and 1.
812  /// e.g. if (!x == 10) or a bitwise and/or operation that always evaluates to
813  /// true/false e.q. (x & 8) == 4.
814  TryResult checkIncorrectEqualityOperator(const BinaryOperator *B) {
815  const Expr *LHSExpr = B->getLHS()->IgnoreParens();
816  const Expr *RHSExpr = B->getRHS()->IgnoreParens();
817 
818  const IntegerLiteral *IntLiteral = dyn_cast<IntegerLiteral>(LHSExpr);
819  const Expr *BoolExpr = RHSExpr;
820 
821  if (!IntLiteral) {
822  IntLiteral = dyn_cast<IntegerLiteral>(RHSExpr);
823  BoolExpr = LHSExpr;
824  }
825 
826  if (!IntLiteral)
827  return TryResult();
828 
829  const BinaryOperator *BitOp = dyn_cast<BinaryOperator>(BoolExpr);
830  if (BitOp && (BitOp->getOpcode() == BO_And ||
831  BitOp->getOpcode() == BO_Or)) {
832  const Expr *LHSExpr2 = BitOp->getLHS()->IgnoreParens();
833  const Expr *RHSExpr2 = BitOp->getRHS()->IgnoreParens();
834 
835  const IntegerLiteral *IntLiteral2 = dyn_cast<IntegerLiteral>(LHSExpr2);
836 
837  if (!IntLiteral2)
838  IntLiteral2 = dyn_cast<IntegerLiteral>(RHSExpr2);
839 
840  if (!IntLiteral2)
841  return TryResult();
842 
843  llvm::APInt L1 = IntLiteral->getValue();
844  llvm::APInt L2 = IntLiteral2->getValue();
845  if ((BitOp->getOpcode() == BO_And && (L2 & L1) != L1) ||
846  (BitOp->getOpcode() == BO_Or && (L2 | L1) != L1)) {
847  if (BuildOpts.Observer)
848  BuildOpts.Observer->compareBitwiseEquality(B,
849  B->getOpcode() != BO_EQ);
850  TryResult(B->getOpcode() != BO_EQ);
851  }
852  } else if (BoolExpr->isKnownToHaveBooleanValue()) {
853  llvm::APInt IntValue = IntLiteral->getValue();
854  if ((IntValue == 1) || (IntValue == 0)) {
855  return TryResult();
856  }
857  return TryResult(B->getOpcode() != BO_EQ);
858  }
859 
860  return TryResult();
861  }
862 
863  TryResult analyzeLogicOperatorCondition(BinaryOperatorKind Relation,
864  const llvm::APSInt &Value1,
865  const llvm::APSInt &Value2) {
866  assert(Value1.isSigned() == Value2.isSigned());
867  switch (Relation) {
868  default:
869  return TryResult();
870  case BO_EQ:
871  return TryResult(Value1 == Value2);
872  case BO_NE:
873  return TryResult(Value1 != Value2);
874  case BO_LT:
875  return TryResult(Value1 < Value2);
876  case BO_LE:
877  return TryResult(Value1 <= Value2);
878  case BO_GT:
879  return TryResult(Value1 > Value2);
880  case BO_GE:
881  return TryResult(Value1 >= Value2);
882  }
883  }
884 
885  /// \brief Find a pair of comparison expressions with or without parentheses
886  /// with a shared variable and constants and a logical operator between them
887  /// that always evaluates to either true or false.
888  /// e.g. if (x != 3 || x != 4)
889  TryResult checkIncorrectLogicOperator(const BinaryOperator *B) {
890  assert(B->isLogicalOp());
891  const BinaryOperator *LHS =
892  dyn_cast<BinaryOperator>(B->getLHS()->IgnoreParens());
893  const BinaryOperator *RHS =
894  dyn_cast<BinaryOperator>(B->getRHS()->IgnoreParens());
895  if (!LHS || !RHS)
896  return {};
897 
898  if (!LHS->isComparisonOp() || !RHS->isComparisonOp())
899  return {};
900 
901  const DeclRefExpr *Decl1;
902  const Expr *Expr1;
903  BinaryOperatorKind BO1;
904  std::tie(Decl1, BO1, Expr1) = tryNormalizeBinaryOperator(LHS);
905 
906  if (!Decl1 || !Expr1)
907  return {};
908 
909  const DeclRefExpr *Decl2;
910  const Expr *Expr2;
911  BinaryOperatorKind BO2;
912  std::tie(Decl2, BO2, Expr2) = tryNormalizeBinaryOperator(RHS);
913 
914  if (!Decl2 || !Expr2)
915  return {};
916 
917  // Check that it is the same variable on both sides.
918  if (Decl1->getDecl() != Decl2->getDecl())
919  return {};
920 
921  // Make sure the user's intent is clear (e.g. they're comparing against two
922  // int literals, or two things from the same enum)
923  if (!areExprTypesCompatible(Expr1, Expr2))
924  return {};
925 
926  llvm::APSInt L1, L2;
927 
928  if (!Expr1->EvaluateAsInt(L1, *Context) ||
929  !Expr2->EvaluateAsInt(L2, *Context))
930  return {};
931 
932  // Can't compare signed with unsigned or with different bit width.
933  if (L1.isSigned() != L2.isSigned() || L1.getBitWidth() != L2.getBitWidth())
934  return {};
935 
936  // Values that will be used to determine if result of logical
937  // operator is always true/false
938  const llvm::APSInt Values[] = {
939  // Value less than both Value1 and Value2
940  llvm::APSInt::getMinValue(L1.getBitWidth(), L1.isUnsigned()),
941  // L1
942  L1,
943  // Value between Value1 and Value2
944  ((L1 < L2) ? L1 : L2) + llvm::APSInt(llvm::APInt(L1.getBitWidth(), 1),
945  L1.isUnsigned()),
946  // L2
947  L2,
948  // Value greater than both Value1 and Value2
949  llvm::APSInt::getMaxValue(L1.getBitWidth(), L1.isUnsigned()),
950  };
951 
952  // Check whether expression is always true/false by evaluating the following
953  // * variable x is less than the smallest literal.
954  // * variable x is equal to the smallest literal.
955  // * Variable x is between smallest and largest literal.
956  // * Variable x is equal to the largest literal.
957  // * Variable x is greater than largest literal.
958  bool AlwaysTrue = true, AlwaysFalse = true;
959  for (const llvm::APSInt &Value : Values) {
960  TryResult Res1, Res2;
961  Res1 = analyzeLogicOperatorCondition(BO1, Value, L1);
962  Res2 = analyzeLogicOperatorCondition(BO2, Value, L2);
963 
964  if (!Res1.isKnown() || !Res2.isKnown())
965  return {};
966 
967  if (B->getOpcode() == BO_LAnd) {
968  AlwaysTrue &= (Res1.isTrue() && Res2.isTrue());
969  AlwaysFalse &= !(Res1.isTrue() && Res2.isTrue());
970  } else {
971  AlwaysTrue &= (Res1.isTrue() || Res2.isTrue());
972  AlwaysFalse &= !(Res1.isTrue() || Res2.isTrue());
973  }
974  }
975 
976  if (AlwaysTrue || AlwaysFalse) {
977  if (BuildOpts.Observer)
978  BuildOpts.Observer->compareAlwaysTrue(B, AlwaysTrue);
979  return TryResult(AlwaysTrue);
980  }
981  return {};
982  }
983 
984  /// Try and evaluate an expression to an integer constant.
985  bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) {
986  if (!BuildOpts.PruneTriviallyFalseEdges)
987  return false;
988  return !S->isTypeDependent() &&
989  !S->isValueDependent() &&
990  S->EvaluateAsRValue(outResult, *Context);
991  }
992 
993  /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1
994  /// if we can evaluate to a known value, otherwise return -1.
995  TryResult tryEvaluateBool(Expr *S) {
996  if (!BuildOpts.PruneTriviallyFalseEdges ||
997  S->isTypeDependent() || S->isValueDependent())
998  return {};
999 
1000  if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(S)) {
1001  if (Bop->isLogicalOp()) {
1002  // Check the cache first.
1003  CachedBoolEvalsTy::iterator I = CachedBoolEvals.find(S);
1004  if (I != CachedBoolEvals.end())
1005  return I->second; // already in map;
1006 
1007  // Retrieve result at first, or the map might be updated.
1008  TryResult Result = evaluateAsBooleanConditionNoCache(S);
1009  CachedBoolEvals[S] = Result; // update or insert
1010  return Result;
1011  }
1012  else {
1013  switch (Bop->getOpcode()) {
1014  default: break;
1015  // For 'x & 0' and 'x * 0', we can determine that
1016  // the value is always false.
1017  case BO_Mul:
1018  case BO_And: {
1019  // If either operand is zero, we know the value
1020  // must be false.
1021  llvm::APSInt IntVal;
1022  if (Bop->getLHS()->EvaluateAsInt(IntVal, *Context)) {
1023  if (!IntVal.getBoolValue()) {
1024  return TryResult(false);
1025  }
1026  }
1027  if (Bop->getRHS()->EvaluateAsInt(IntVal, *Context)) {
1028  if (!IntVal.getBoolValue()) {
1029  return TryResult(false);
1030  }
1031  }
1032  }
1033  break;
1034  }
1035  }
1036  }
1037 
1038  return evaluateAsBooleanConditionNoCache(S);
1039  }
1040 
1041  /// \brief Evaluate as boolean \param E without using the cache.
1042  TryResult evaluateAsBooleanConditionNoCache(Expr *E) {
1043  if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(E)) {
1044  if (Bop->isLogicalOp()) {
1045  TryResult LHS = tryEvaluateBool(Bop->getLHS());
1046  if (LHS.isKnown()) {
1047  // We were able to evaluate the LHS, see if we can get away with not
1048  // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
1049  if (LHS.isTrue() == (Bop->getOpcode() == BO_LOr))
1050  return LHS.isTrue();
1051 
1052  TryResult RHS = tryEvaluateBool(Bop->getRHS());
1053  if (RHS.isKnown()) {
1054  if (Bop->getOpcode() == BO_LOr)
1055  return LHS.isTrue() || RHS.isTrue();
1056  else
1057  return LHS.isTrue() && RHS.isTrue();
1058  }
1059  } else {
1060  TryResult RHS = tryEvaluateBool(Bop->getRHS());
1061  if (RHS.isKnown()) {
1062  // We can't evaluate the LHS; however, sometimes the result
1063  // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
1064  if (RHS.isTrue() == (Bop->getOpcode() == BO_LOr))
1065  return RHS.isTrue();
1066  } else {
1067  TryResult BopRes = checkIncorrectLogicOperator(Bop);
1068  if (BopRes.isKnown())
1069  return BopRes.isTrue();
1070  }
1071  }
1072 
1073  return {};
1074  } else if (Bop->isEqualityOp()) {
1075  TryResult BopRes = checkIncorrectEqualityOperator(Bop);
1076  if (BopRes.isKnown())
1077  return BopRes.isTrue();
1078  } else if (Bop->isRelationalOp()) {
1079  TryResult BopRes = checkIncorrectRelationalOperator(Bop);
1080  if (BopRes.isKnown())
1081  return BopRes.isTrue();
1082  }
1083  }
1084 
1085  bool Result;
1086  if (E->EvaluateAsBooleanCondition(Result, *Context))
1087  return Result;
1088 
1089  return {};
1090  }
1091 
1092  bool hasTrivialDestructor(VarDecl *VD);
1093 };
1094 
1095 } // namespace
1096 
1097 inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder,
1098  const Stmt *stmt) const {
1099  return builder.alwaysAdd(stmt) || kind == AlwaysAdd;
1100 }
1101 
1102 bool CFGBuilder::alwaysAdd(const Stmt *stmt) {
1103  bool shouldAdd = BuildOpts.alwaysAdd(stmt);
1104 
1105  if (!BuildOpts.forcedBlkExprs)
1106  return shouldAdd;
1107 
1108  if (lastLookup == stmt) {
1109  if (cachedEntry) {
1110  assert(cachedEntry->first == stmt);
1111  return true;
1112  }
1113  return shouldAdd;
1114  }
1115 
1116  lastLookup = stmt;
1117 
1118  // Perform the lookup!
1119  CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs;
1120 
1121  if (!fb) {
1122  // No need to update 'cachedEntry', since it will always be null.
1123  assert(!cachedEntry);
1124  return shouldAdd;
1125  }
1126 
1127  CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt);
1128  if (itr == fb->end()) {
1129  cachedEntry = nullptr;
1130  return shouldAdd;
1131  }
1132 
1133  cachedEntry = &*itr;
1134  return true;
1135 }
1136 
1137 // FIXME: Add support for dependent-sized array types in C++?
1138 // Does it even make sense to build a CFG for an uninstantiated template?
1139 static const VariableArrayType *FindVA(const Type *t) {
1140  while (const ArrayType *vt = dyn_cast<ArrayType>(t)) {
1141  if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt))
1142  if (vat->getSizeExpr())
1143  return vat;
1144 
1145  t = vt->getElementType().getTypePtr();
1146  }
1147 
1148  return nullptr;
1149 }
1150 
1151 void CFGBuilder::EnterConstructionContextIfNecessary(
1152  ConstructionContext::TriggerTy Trigger, Stmt *Child) {
1153  if (!BuildOpts.AddRichCXXConstructors)
1154  return;
1155  if (!Child)
1156  return;
1157  if (isa<CXXConstructExpr>(Child)) {
1158  assert(CurrentConstructionContext.isNull() &&
1159  "Already within a construction context!");
1160  CurrentConstructionContext = ConstructionContext(Trigger);
1161  } else if (auto *Cleanups = dyn_cast<ExprWithCleanups>(Child)) {
1162  EnterConstructionContextIfNecessary(Trigger, Cleanups->getSubExpr());
1163  }
1164 }
1165 
1166 void CFGBuilder::ExitConstructionContext() {
1167  assert(!CurrentConstructionContext.isNull() &&
1168  "Cannot exit construction context without the context!");
1169  CurrentConstructionContext = ConstructionContext();
1170 }
1171 
1172 
1173 /// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an
1174 /// arbitrary statement. Examples include a single expression or a function
1175 /// body (compound statement). The ownership of the returned CFG is
1176 /// transferred to the caller. If CFG construction fails, this method returns
1177 /// NULL.
1178 std::unique_ptr<CFG> CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) {
1179  assert(cfg.get());
1180  if (!Statement)
1181  return nullptr;
1182 
1183  // Create an empty block that will serve as the exit block for the CFG. Since
1184  // this is the first block added to the CFG, it will be implicitly registered
1185  // as the exit block.
1186  Succ = createBlock();
1187  assert(Succ == &cfg->getExit());
1188  Block = nullptr; // the EXIT block is empty. Create all other blocks lazily.
1189 
1190  assert(!(BuildOpts.AddImplicitDtors && BuildOpts.AddLifetime) &&
1191  "AddImplicitDtors and AddLifetime cannot be used at the same time");
1192 
1193  if (BuildOpts.AddImplicitDtors)
1194  if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D))
1195  addImplicitDtorsForDestructor(DD);
1196 
1197  // Visit the statements and create the CFG.
1198  CFGBlock *B = addStmt(Statement);
1199 
1200  if (badCFG)
1201  return nullptr;
1202 
1203  // For C++ constructor add initializers to CFG.
1204  if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) {
1205  for (auto *I : llvm::reverse(CD->inits())) {
1206  B = addInitializer(I);
1207  if (badCFG)
1208  return nullptr;
1209  }
1210  }
1211 
1212  if (B)
1213  Succ = B;
1214 
1215  // Backpatch the gotos whose label -> block mappings we didn't know when we
1216  // encountered them.
1217  for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(),
1218  E = BackpatchBlocks.end(); I != E; ++I ) {
1219 
1220  CFGBlock *B = I->block;
1221  const GotoStmt *G = cast<GotoStmt>(B->getTerminator());
1222  LabelMapTy::iterator LI = LabelMap.find(G->getLabel());
1223 
1224  // If there is no target for the goto, then we are looking at an
1225  // incomplete AST. Handle this by not registering a successor.
1226  if (LI == LabelMap.end()) continue;
1227 
1228  JumpTarget JT = LI->second;
1229  prependAutomaticObjLifetimeWithTerminator(B, I->scopePosition,
1230  JT.scopePosition);
1231  prependAutomaticObjDtorsWithTerminator(B, I->scopePosition,
1232  JT.scopePosition);
1233  addSuccessor(B, JT.block);
1234  }
1235 
1236  // Add successors to the Indirect Goto Dispatch block (if we have one).
1237  if (CFGBlock *B = cfg->getIndirectGotoBlock())
1238  for (LabelSetTy::iterator I = AddressTakenLabels.begin(),
1239  E = AddressTakenLabels.end(); I != E; ++I ) {
1240  // Lookup the target block.
1241  LabelMapTy::iterator LI = LabelMap.find(*I);
1242 
1243  // If there is no target block that contains label, then we are looking
1244  // at an incomplete AST. Handle this by not registering a successor.
1245  if (LI == LabelMap.end()) continue;
1246 
1247  addSuccessor(B, LI->second.block);
1248  }
1249 
1250  // Create an empty entry block that has no predecessors.
1251  cfg->setEntry(createBlock());
1252 
1253  return std::move(cfg);
1254 }
1255 
1256 /// createBlock - Used to lazily create blocks that are connected
1257 /// to the current (global) succcessor.
1258 CFGBlock *CFGBuilder::createBlock(bool add_successor) {
1259  CFGBlock *B = cfg->createBlock();
1260  if (add_successor && Succ)
1261  addSuccessor(B, Succ);
1262  return B;
1263 }
1264 
1265 /// createNoReturnBlock - Used to create a block is a 'noreturn' point in the
1266 /// CFG. It is *not* connected to the current (global) successor, and instead
1267 /// directly tied to the exit block in order to be reachable.
1268 CFGBlock *CFGBuilder::createNoReturnBlock() {
1269  CFGBlock *B = createBlock(false);
1270  B->setHasNoReturnElement();
1271  addSuccessor(B, &cfg->getExit(), Succ);
1272  return B;
1273 }
1274 
1275 /// addInitializer - Add C++ base or member initializer element to CFG.
1276 CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) {
1277  if (!BuildOpts.AddInitializers)
1278  return Block;
1279 
1280  bool HasTemporaries = false;
1281 
1282  // Destructors of temporaries in initialization expression should be called
1283  // after initialization finishes.
1284  Expr *Init = I->getInit();
1285  if (Init) {
1286  HasTemporaries = isa<ExprWithCleanups>(Init);
1287 
1288  if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
1289  // Generate destructors for temporaries in initialization expression.
1290  TempDtorContext Context;
1291  VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
1292  /*BindToTemporary=*/false, Context);
1293  }
1294  }
1295 
1296  autoCreateBlock();
1297  appendInitializer(Block, I);
1298 
1299  if (Init) {
1300  EnterConstructionContextIfNecessary(I, Init);
1301 
1302  if (HasTemporaries) {
1303  // For expression with temporaries go directly to subexpression to omit
1304  // generating destructors for the second time.
1305  return Visit(cast<ExprWithCleanups>(Init)->getSubExpr());
1306  }
1307  if (BuildOpts.AddCXXDefaultInitExprInCtors) {
1308  if (CXXDefaultInitExpr *Default = dyn_cast<CXXDefaultInitExpr>(Init)) {
1309  // In general, appending the expression wrapped by a CXXDefaultInitExpr
1310  // may cause the same Expr to appear more than once in the CFG. Doing it
1311  // here is safe because there's only one initializer per field.
1312  autoCreateBlock();
1313  appendStmt(Block, Default);
1314  if (Stmt *Child = Default->getExpr())
1315  if (CFGBlock *R = Visit(Child))
1316  Block = R;
1317  return Block;
1318  }
1319  }
1320  return Visit(Init);
1321  }
1322 
1323  return Block;
1324 }
1325 
1326 /// \brief Retrieve the type of the temporary object whose lifetime was
1327 /// extended by a local reference with the given initializer.
1329  const Expr *Init,
1330  bool *FoundMTE = nullptr) {
1331  while (true) {
1332  // Skip parentheses.
1333  Init = Init->IgnoreParens();
1334 
1335  // Skip through cleanups.
1336  if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Init)) {
1337  Init = EWC->getSubExpr();
1338  continue;
1339  }
1340 
1341  // Skip through the temporary-materialization expression.
1342  if (const MaterializeTemporaryExpr *MTE
1343  = dyn_cast<MaterializeTemporaryExpr>(Init)) {
1344  Init = MTE->GetTemporaryExpr();
1345  if (FoundMTE)
1346  *FoundMTE = true;
1347  continue;
1348  }
1349 
1350  // Skip derived-to-base and no-op casts.
1351  if (const CastExpr *CE = dyn_cast<CastExpr>(Init)) {
1352  if ((CE->getCastKind() == CK_DerivedToBase ||
1353  CE->getCastKind() == CK_UncheckedDerivedToBase ||
1354  CE->getCastKind() == CK_NoOp) &&
1355  Init->getType()->isRecordType()) {
1356  Init = CE->getSubExpr();
1357  continue;
1358  }
1359  }
1360 
1361  // Skip member accesses into rvalues.
1362  if (const MemberExpr *ME = dyn_cast<MemberExpr>(Init)) {
1363  if (!ME->isArrow() && ME->getBase()->isRValue()) {
1364  Init = ME->getBase();
1365  continue;
1366  }
1367  }
1368 
1369  break;
1370  }
1371 
1372  return Init->getType();
1373 }
1374 
1375 // TODO: Support adding LoopExit element to the CFG in case where the loop is
1376 // ended by ReturnStmt, GotoStmt or ThrowExpr.
1377 void CFGBuilder::addLoopExit(const Stmt *LoopStmt){
1378  if(!BuildOpts.AddLoopExit)
1379  return;
1380  autoCreateBlock();
1381  appendLoopExit(Block, LoopStmt);
1382 }
1383 
1384 void CFGBuilder::addAutomaticObjHandling(LocalScope::const_iterator B,
1385  LocalScope::const_iterator E,
1386  Stmt *S) {
1387  if (BuildOpts.AddImplicitDtors)
1388  addAutomaticObjDtors(B, E, S);
1389  if (BuildOpts.AddLifetime)
1390  addLifetimeEnds(B, E, S);
1391 }
1392 
1393 /// Add to current block automatic objects that leave the scope.
1394 void CFGBuilder::addLifetimeEnds(LocalScope::const_iterator B,
1395  LocalScope::const_iterator E, Stmt *S) {
1396  if (!BuildOpts.AddLifetime)
1397  return;
1398 
1399  if (B == E)
1400  return;
1401 
1402  // To go from B to E, one first goes up the scopes from B to P
1403  // then sideways in one scope from P to P' and then down
1404  // the scopes from P' to E.
1405  // The lifetime of all objects between B and P end.
1406  LocalScope::const_iterator P = B.shared_parent(E);
1407  int dist = B.distance(P);
1408  if (dist <= 0)
1409  return;
1410 
1411  // We need to perform the scope leaving in reverse order
1412  SmallVector<VarDecl *, 10> DeclsTrivial;
1413  SmallVector<VarDecl *, 10> DeclsNonTrivial;
1414  DeclsTrivial.reserve(dist);
1415  DeclsNonTrivial.reserve(dist);
1416 
1417  for (LocalScope::const_iterator I = B; I != P; ++I)
1418  if (hasTrivialDestructor(*I))
1419  DeclsTrivial.push_back(*I);
1420  else
1421  DeclsNonTrivial.push_back(*I);
1422 
1423  autoCreateBlock();
1424  // object with trivial destructor end their lifetime last (when storage
1425  // duration ends)
1426  for (SmallVectorImpl<VarDecl *>::reverse_iterator I = DeclsTrivial.rbegin(),
1427  E = DeclsTrivial.rend();
1428  I != E; ++I)
1429  appendLifetimeEnds(Block, *I, S);
1430 
1432  I = DeclsNonTrivial.rbegin(),
1433  E = DeclsNonTrivial.rend();
1434  I != E; ++I)
1435  appendLifetimeEnds(Block, *I, S);
1436 }
1437 
1438 /// addAutomaticObjDtors - Add to current block automatic objects destructors
1439 /// for objects in range of local scope positions. Use S as trigger statement
1440 /// for destructors.
1441 void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B,
1442  LocalScope::const_iterator E, Stmt *S) {
1443  if (!BuildOpts.AddImplicitDtors)
1444  return;
1445 
1446  if (B == E)
1447  return;
1448 
1449  // We need to append the destructors in reverse order, but any one of them
1450  // may be a no-return destructor which changes the CFG. As a result, buffer
1451  // this sequence up and replay them in reverse order when appending onto the
1452  // CFGBlock(s).
1454  Decls.reserve(B.distance(E));
1455  for (LocalScope::const_iterator I = B; I != E; ++I)
1456  Decls.push_back(*I);
1457 
1458  for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(),
1459  E = Decls.rend();
1460  I != E; ++I) {
1461  // If this destructor is marked as a no-return destructor, we need to
1462  // create a new block for the destructor which does not have as a successor
1463  // anything built thus far: control won't flow out of this block.
1464  QualType Ty = (*I)->getType();
1465  if (Ty->isReferenceType()) {
1466  Ty = getReferenceInitTemporaryType(*Context, (*I)->getInit());
1467  }
1468  Ty = Context->getBaseElementType(Ty);
1469 
1470  if (Ty->getAsCXXRecordDecl()->isAnyDestructorNoReturn())
1471  Block = createNoReturnBlock();
1472  else
1473  autoCreateBlock();
1474 
1475  appendAutomaticObjDtor(Block, *I, S);
1476  }
1477 }
1478 
1479 /// addImplicitDtorsForDestructor - Add implicit destructors generated for
1480 /// base and member objects in destructor.
1481 void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) {
1482  assert(BuildOpts.AddImplicitDtors &&
1483  "Can be called only when dtors should be added");
1484  const CXXRecordDecl *RD = DD->getParent();
1485 
1486  // At the end destroy virtual base objects.
1487  for (const auto &VI : RD->vbases()) {
1488  const CXXRecordDecl *CD = VI.getType()->getAsCXXRecordDecl();
1489  if (!CD->hasTrivialDestructor()) {
1490  autoCreateBlock();
1491  appendBaseDtor(Block, &VI);
1492  }
1493  }
1494 
1495  // Before virtual bases destroy direct base objects.
1496  for (const auto &BI : RD->bases()) {
1497  if (!BI.isVirtual()) {
1498  const CXXRecordDecl *CD = BI.getType()->getAsCXXRecordDecl();
1499  if (!CD->hasTrivialDestructor()) {
1500  autoCreateBlock();
1501  appendBaseDtor(Block, &BI);
1502  }
1503  }
1504  }
1505 
1506  // First destroy member objects.
1507  for (auto *FI : RD->fields()) {
1508  // Check for constant size array. Set type to array element type.
1509  QualType QT = FI->getType();
1510  if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
1511  if (AT->getSize() == 0)
1512  continue;
1513  QT = AT->getElementType();
1514  }
1515 
1516  if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
1517  if (!CD->hasTrivialDestructor()) {
1518  autoCreateBlock();
1519  appendMemberDtor(Block, FI);
1520  }
1521  }
1522 }
1523 
1524 /// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either
1525 /// way return valid LocalScope object.
1526 LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) {
1527  if (Scope)
1528  return Scope;
1529  llvm::BumpPtrAllocator &alloc = cfg->getAllocator();
1530  return new (alloc.Allocate<LocalScope>())
1531  LocalScope(BumpVectorContext(alloc), ScopePos);
1532 }
1533 
1534 /// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement
1535 /// that should create implicit scope (e.g. if/else substatements).
1536 void CFGBuilder::addLocalScopeForStmt(Stmt *S) {
1537  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime)
1538  return;
1539 
1540  LocalScope *Scope = nullptr;
1541 
1542  // For compound statement we will be creating explicit scope.
1543  if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
1544  for (auto *BI : CS->body()) {
1545  Stmt *SI = BI->stripLabelLikeStatements();
1546  if (DeclStmt *DS = dyn_cast<DeclStmt>(SI))
1547  Scope = addLocalScopeForDeclStmt(DS, Scope);
1548  }
1549  return;
1550  }
1551 
1552  // For any other statement scope will be implicit and as such will be
1553  // interesting only for DeclStmt.
1554  if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements()))
1555  addLocalScopeForDeclStmt(DS);
1556 }
1557 
1558 /// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will
1559 /// reuse Scope if not NULL.
1560 LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS,
1561  LocalScope* Scope) {
1562  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime)
1563  return Scope;
1564 
1565  for (auto *DI : DS->decls())
1566  if (VarDecl *VD = dyn_cast<VarDecl>(DI))
1567  Scope = addLocalScopeForVarDecl(VD, Scope);
1568  return Scope;
1569 }
1570 
1571 bool CFGBuilder::hasTrivialDestructor(VarDecl *VD) {
1572  // Check for const references bound to temporary. Set type to pointee.
1573  QualType QT = VD->getType();
1574  if (QT.getTypePtr()->isReferenceType()) {
1575  // Attempt to determine whether this declaration lifetime-extends a
1576  // temporary.
1577  //
1578  // FIXME: This is incorrect. Non-reference declarations can lifetime-extend
1579  // temporaries, and a single declaration can extend multiple temporaries.
1580  // We should look at the storage duration on each nested
1581  // MaterializeTemporaryExpr instead.
1582 
1583  const Expr *Init = VD->getInit();
1584  if (!Init)
1585  return true;
1586 
1587  // Lifetime-extending a temporary.
1588  bool FoundMTE = false;
1589  QT = getReferenceInitTemporaryType(*Context, Init, &FoundMTE);
1590  if (!FoundMTE)
1591  return true;
1592  }
1593 
1594  // Check for constant size array. Set type to array element type.
1595  while (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
1596  if (AT->getSize() == 0)
1597  return true;
1598  QT = AT->getElementType();
1599  }
1600 
1601  // Check if type is a C++ class with non-trivial destructor.
1602  if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
1603  return !CD->hasDefinition() || CD->hasTrivialDestructor();
1604  return true;
1605 }
1606 
1607 /// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will
1608 /// create add scope for automatic objects and temporary objects bound to
1609 /// const reference. Will reuse Scope if not NULL.
1610 LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD,
1611  LocalScope* Scope) {
1612  assert(!(BuildOpts.AddImplicitDtors && BuildOpts.AddLifetime) &&
1613  "AddImplicitDtors and AddLifetime cannot be used at the same time");
1614  if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime)
1615  return Scope;
1616 
1617  // Check if variable is local.
1618  switch (VD->getStorageClass()) {
1619  case SC_None:
1620  case SC_Auto:
1621  case SC_Register:
1622  break;
1623  default: return Scope;
1624  }
1625 
1626  if (BuildOpts.AddImplicitDtors) {
1627  if (!hasTrivialDestructor(VD)) {
1628  // Add the variable to scope
1629  Scope = createOrReuseLocalScope(Scope);
1630  Scope->addVar(VD);
1631  ScopePos = Scope->begin();
1632  }
1633  return Scope;
1634  }
1635 
1636  assert(BuildOpts.AddLifetime);
1637  // Add the variable to scope
1638  Scope = createOrReuseLocalScope(Scope);
1639  Scope->addVar(VD);
1640  ScopePos = Scope->begin();
1641  return Scope;
1642 }
1643 
1644 /// addLocalScopeAndDtors - For given statement add local scope for it and
1645 /// add destructors that will cleanup the scope. Will reuse Scope if not NULL.
1646 void CFGBuilder::addLocalScopeAndDtors(Stmt *S) {
1647  LocalScope::const_iterator scopeBeginPos = ScopePos;
1648  addLocalScopeForStmt(S);
1649  addAutomaticObjHandling(ScopePos, scopeBeginPos, S);
1650 }
1651 
1652 /// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for
1653 /// variables with automatic storage duration to CFGBlock's elements vector.
1654 /// Elements will be prepended to physical beginning of the vector which
1655 /// happens to be logical end. Use blocks terminator as statement that specifies
1656 /// destructors call site.
1657 /// FIXME: This mechanism for adding automatic destructors doesn't handle
1658 /// no-return destructors properly.
1659 void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
1660  LocalScope::const_iterator B, LocalScope::const_iterator E) {
1661  if (!BuildOpts.AddImplicitDtors)
1662  return;
1663  BumpVectorContext &C = cfg->getBumpVectorContext();
1664  CFGBlock::iterator InsertPos
1665  = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C);
1666  for (LocalScope::const_iterator I = B; I != E; ++I)
1667  InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I,
1668  Blk->getTerminator());
1669 }
1670 
1671 /// prependAutomaticObjLifetimeWithTerminator - Prepend lifetime CFGElements for
1672 /// variables with automatic storage duration to CFGBlock's elements vector.
1673 /// Elements will be prepended to physical beginning of the vector which
1674 /// happens to be logical end. Use blocks terminator as statement that specifies
1675 /// where lifetime ends.
1676 void CFGBuilder::prependAutomaticObjLifetimeWithTerminator(
1677  CFGBlock *Blk, LocalScope::const_iterator B, LocalScope::const_iterator E) {
1678  if (!BuildOpts.AddLifetime)
1679  return;
1680  BumpVectorContext &C = cfg->getBumpVectorContext();
1681  CFGBlock::iterator InsertPos =
1682  Blk->beginLifetimeEndsInsert(Blk->end(), B.distance(E), C);
1683  for (LocalScope::const_iterator I = B; I != E; ++I)
1684  InsertPos = Blk->insertLifetimeEnds(InsertPos, *I, Blk->getTerminator());
1685 }
1686 
1687 /// Visit - Walk the subtree of a statement and add extra
1688 /// blocks for ternary operators, &&, and ||. We also process "," and
1689 /// DeclStmts (which may contain nested control-flow).
1690 CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) {
1691  if (!S) {
1692  badCFG = true;
1693  return nullptr;
1694  }
1695 
1696  if (Expr *E = dyn_cast<Expr>(S))
1697  S = E->IgnoreParens();
1698 
1699  switch (S->getStmtClass()) {
1700  default:
1701  return VisitStmt(S, asc);
1702 
1703  case Stmt::AddrLabelExprClass:
1704  return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc);
1705 
1706  case Stmt::BinaryConditionalOperatorClass:
1707  return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc);
1708 
1709  case Stmt::BinaryOperatorClass:
1710  return VisitBinaryOperator(cast<BinaryOperator>(S), asc);
1711 
1712  case Stmt::BlockExprClass:
1713  return VisitBlockExpr(cast<BlockExpr>(S), asc);
1714 
1715  case Stmt::BreakStmtClass:
1716  return VisitBreakStmt(cast<BreakStmt>(S));
1717 
1718  case Stmt::CallExprClass:
1719  case Stmt::CXXOperatorCallExprClass:
1720  case Stmt::CXXMemberCallExprClass:
1721  case Stmt::UserDefinedLiteralClass:
1722  return VisitCallExpr(cast<CallExpr>(S), asc);
1723 
1724  case Stmt::CaseStmtClass:
1725  return VisitCaseStmt(cast<CaseStmt>(S));
1726 
1727  case Stmt::ChooseExprClass:
1728  return VisitChooseExpr(cast<ChooseExpr>(S), asc);
1729 
1730  case Stmt::CompoundStmtClass:
1731  return VisitCompoundStmt(cast<CompoundStmt>(S));
1732 
1733  case Stmt::ConditionalOperatorClass:
1734  return VisitConditionalOperator(cast<ConditionalOperator>(S), asc);
1735 
1736  case Stmt::ContinueStmtClass:
1737  return VisitContinueStmt(cast<ContinueStmt>(S));
1738 
1739  case Stmt::CXXCatchStmtClass:
1740  return VisitCXXCatchStmt(cast<CXXCatchStmt>(S));
1741 
1742  case Stmt::ExprWithCleanupsClass:
1743  return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc);
1744 
1745  case Stmt::CXXDefaultArgExprClass:
1746  case Stmt::CXXDefaultInitExprClass:
1747  // FIXME: The expression inside a CXXDefaultArgExpr is owned by the
1748  // called function's declaration, not by the caller. If we simply add
1749  // this expression to the CFG, we could end up with the same Expr
1750  // appearing multiple times.
1751  // PR13385 / <rdar://problem/12156507>
1752  //
1753  // It's likewise possible for multiple CXXDefaultInitExprs for the same
1754  // expression to be used in the same function (through aggregate
1755  // initialization).
1756  return VisitStmt(S, asc);
1757 
1758  case Stmt::CXXBindTemporaryExprClass:
1759  return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc);
1760 
1761  case Stmt::CXXConstructExprClass:
1762  return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc);
1763 
1764  case Stmt::CXXNewExprClass:
1765  return VisitCXXNewExpr(cast<CXXNewExpr>(S), asc);
1766 
1767  case Stmt::CXXDeleteExprClass:
1768  return VisitCXXDeleteExpr(cast<CXXDeleteExpr>(S), asc);
1769 
1770  case Stmt::CXXFunctionalCastExprClass:
1771  return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc);
1772 
1773  case Stmt::CXXTemporaryObjectExprClass:
1774  return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc);
1775 
1776  case Stmt::CXXThrowExprClass:
1777  return VisitCXXThrowExpr(cast<CXXThrowExpr>(S));
1778 
1779  case Stmt::CXXTryStmtClass:
1780  return VisitCXXTryStmt(cast<CXXTryStmt>(S));
1781 
1782  case Stmt::CXXForRangeStmtClass:
1783  return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S));
1784 
1785  case Stmt::DeclStmtClass:
1786  return VisitDeclStmt(cast<DeclStmt>(S));
1787 
1788  case Stmt::DefaultStmtClass:
1789  return VisitDefaultStmt(cast<DefaultStmt>(S));
1790 
1791  case Stmt::DoStmtClass:
1792  return VisitDoStmt(cast<DoStmt>(S));
1793 
1794  case Stmt::ForStmtClass:
1795  return VisitForStmt(cast<ForStmt>(S));
1796 
1797  case Stmt::GotoStmtClass:
1798  return VisitGotoStmt(cast<GotoStmt>(S));
1799 
1800  case Stmt::IfStmtClass:
1801  return VisitIfStmt(cast<IfStmt>(S));
1802 
1803  case Stmt::ImplicitCastExprClass:
1804  return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc);
1805 
1806  case Stmt::IndirectGotoStmtClass:
1807  return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S));
1808 
1809  case Stmt::LabelStmtClass:
1810  return VisitLabelStmt(cast<LabelStmt>(S));
1811 
1812  case Stmt::LambdaExprClass:
1813  return VisitLambdaExpr(cast<LambdaExpr>(S), asc);
1814 
1815  case Stmt::MemberExprClass:
1816  return VisitMemberExpr(cast<MemberExpr>(S), asc);
1817 
1818  case Stmt::NullStmtClass:
1819  return Block;
1820 
1821  case Stmt::ObjCAtCatchStmtClass:
1822  return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S));
1823 
1824  case Stmt::ObjCAutoreleasePoolStmtClass:
1825  return VisitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(S));
1826 
1827  case Stmt::ObjCAtSynchronizedStmtClass:
1828  return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S));
1829 
1830  case Stmt::ObjCAtThrowStmtClass:
1831  return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S));
1832 
1833  case Stmt::ObjCAtTryStmtClass:
1834  return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S));
1835 
1836  case Stmt::ObjCForCollectionStmtClass:
1837  return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S));
1838 
1839  case Stmt::OpaqueValueExprClass:
1840  return Block;
1841 
1842  case Stmt::PseudoObjectExprClass:
1843  return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S));
1844 
1845  case Stmt::ReturnStmtClass:
1846  return VisitReturnStmt(cast<ReturnStmt>(S));
1847 
1848  case Stmt::SEHExceptStmtClass:
1849  return VisitSEHExceptStmt(cast<SEHExceptStmt>(S));
1850 
1851  case Stmt::SEHFinallyStmtClass:
1852  return VisitSEHFinallyStmt(cast<SEHFinallyStmt>(S));
1853 
1854  case Stmt::SEHLeaveStmtClass:
1855  return VisitSEHLeaveStmt(cast<SEHLeaveStmt>(S));
1856 
1857  case Stmt::SEHTryStmtClass:
1858  return VisitSEHTryStmt(cast<SEHTryStmt>(S));
1859 
1860  case Stmt::UnaryExprOrTypeTraitExprClass:
1861  return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S),
1862  asc);
1863 
1864  case Stmt::StmtExprClass:
1865  return VisitStmtExpr(cast<StmtExpr>(S), asc);
1866 
1867  case Stmt::SwitchStmtClass:
1868  return VisitSwitchStmt(cast<SwitchStmt>(S));
1869 
1870  case Stmt::UnaryOperatorClass:
1871  return VisitUnaryOperator(cast<UnaryOperator>(S), asc);
1872 
1873  case Stmt::WhileStmtClass:
1874  return VisitWhileStmt(cast<WhileStmt>(S));
1875  }
1876 }
1877 
1878 CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) {
1879  if (asc.alwaysAdd(*this, S)) {
1880  autoCreateBlock();
1881  appendStmt(Block, S);
1882  }
1883 
1884  return VisitChildren(S);
1885 }
1886 
1887 /// VisitChildren - Visit the children of a Stmt.
1888 CFGBlock *CFGBuilder::VisitChildren(Stmt *S) {
1889  CFGBlock *B = Block;
1890 
1891  // Visit the children in their reverse order so that they appear in
1892  // left-to-right (natural) order in the CFG.
1893  reverse_children RChildren(S);
1894  for (reverse_children::iterator I = RChildren.begin(), E = RChildren.end();
1895  I != E; ++I) {
1896  if (Stmt *Child = *I)
1897  if (CFGBlock *R = Visit(Child))
1898  B = R;
1899  }
1900  return B;
1901 }
1902 
1903 CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A,
1904  AddStmtChoice asc) {
1905  AddressTakenLabels.insert(A->getLabel());
1906 
1907  if (asc.alwaysAdd(*this, A)) {
1908  autoCreateBlock();
1909  appendStmt(Block, A);
1910  }
1911 
1912  return Block;
1913 }
1914 
1915 CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U,
1916  AddStmtChoice asc) {
1917  if (asc.alwaysAdd(*this, U)) {
1918  autoCreateBlock();
1919  appendStmt(Block, U);
1920  }
1921 
1922  return Visit(U->getSubExpr(), AddStmtChoice());
1923 }
1924 
1925 CFGBlock *CFGBuilder::VisitLogicalOperator(BinaryOperator *B) {
1926  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
1927  appendStmt(ConfluenceBlock, B);
1928 
1929  if (badCFG)
1930  return nullptr;
1931 
1932  return VisitLogicalOperator(B, nullptr, ConfluenceBlock,
1933  ConfluenceBlock).first;
1934 }
1935 
1936 std::pair<CFGBlock*, CFGBlock*>
1937 CFGBuilder::VisitLogicalOperator(BinaryOperator *B,
1938  Stmt *Term,
1939  CFGBlock *TrueBlock,
1940  CFGBlock *FalseBlock) {
1941  // Introspect the RHS. If it is a nested logical operation, we recursively
1942  // build the CFG using this function. Otherwise, resort to default
1943  // CFG construction behavior.
1944  Expr *RHS = B->getRHS()->IgnoreParens();
1945  CFGBlock *RHSBlock, *ExitBlock;
1946 
1947  do {
1948  if (BinaryOperator *B_RHS = dyn_cast<BinaryOperator>(RHS))
1949  if (B_RHS->isLogicalOp()) {
1950  std::tie(RHSBlock, ExitBlock) =
1951  VisitLogicalOperator(B_RHS, Term, TrueBlock, FalseBlock);
1952  break;
1953  }
1954 
1955  // The RHS is not a nested logical operation. Don't push the terminator
1956  // down further, but instead visit RHS and construct the respective
1957  // pieces of the CFG, and link up the RHSBlock with the terminator
1958  // we have been provided.
1959  ExitBlock = RHSBlock = createBlock(false);
1960 
1961  // Even though KnownVal is only used in the else branch of the next
1962  // conditional, tryEvaluateBool performs additional checking on the
1963  // Expr, so it should be called unconditionally.
1964  TryResult KnownVal = tryEvaluateBool(RHS);
1965  if (!KnownVal.isKnown())
1966  KnownVal = tryEvaluateBool(B);
1967 
1968  if (!Term) {
1969  assert(TrueBlock == FalseBlock);
1970  addSuccessor(RHSBlock, TrueBlock);
1971  }
1972  else {
1973  RHSBlock->setTerminator(Term);
1974  addSuccessor(RHSBlock, TrueBlock, !KnownVal.isFalse());
1975  addSuccessor(RHSBlock, FalseBlock, !KnownVal.isTrue());
1976  }
1977 
1978  Block = RHSBlock;
1979  RHSBlock = addStmt(RHS);
1980  }
1981  while (false);
1982 
1983  if (badCFG)
1984  return std::make_pair(nullptr, nullptr);
1985 
1986  // Generate the blocks for evaluating the LHS.
1987  Expr *LHS = B->getLHS()->IgnoreParens();
1988 
1989  if (BinaryOperator *B_LHS = dyn_cast<BinaryOperator>(LHS))
1990  if (B_LHS->isLogicalOp()) {
1991  if (B->getOpcode() == BO_LOr)
1992  FalseBlock = RHSBlock;
1993  else
1994  TrueBlock = RHSBlock;
1995 
1996  // For the LHS, treat 'B' as the terminator that we want to sink
1997  // into the nested branch. The RHS always gets the top-most
1998  // terminator.
1999  return VisitLogicalOperator(B_LHS, B, TrueBlock, FalseBlock);
2000  }
2001 
2002  // Create the block evaluating the LHS.
2003  // This contains the '&&' or '||' as the terminator.
2004  CFGBlock *LHSBlock = createBlock(false);
2005  LHSBlock->setTerminator(B);
2006 
2007  Block = LHSBlock;
2008  CFGBlock *EntryLHSBlock = addStmt(LHS);
2009 
2010  if (badCFG)
2011  return std::make_pair(nullptr, nullptr);
2012 
2013  // See if this is a known constant.
2014  TryResult KnownVal = tryEvaluateBool(LHS);
2015 
2016  // Now link the LHSBlock with RHSBlock.
2017  if (B->getOpcode() == BO_LOr) {
2018  addSuccessor(LHSBlock, TrueBlock, !KnownVal.isFalse());
2019  addSuccessor(LHSBlock, RHSBlock, !KnownVal.isTrue());
2020  } else {
2021  assert(B->getOpcode() == BO_LAnd);
2022  addSuccessor(LHSBlock, RHSBlock, !KnownVal.isFalse());
2023  addSuccessor(LHSBlock, FalseBlock, !KnownVal.isTrue());
2024  }
2025 
2026  return std::make_pair(EntryLHSBlock, ExitBlock);
2027 }
2028 
2029 CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B,
2030  AddStmtChoice asc) {
2031  // && or ||
2032  if (B->isLogicalOp())
2033  return VisitLogicalOperator(B);
2034 
2035  if (B->getOpcode() == BO_Comma) { // ,
2036  autoCreateBlock();
2037  appendStmt(Block, B);
2038  addStmt(B->getRHS());
2039  return addStmt(B->getLHS());
2040  }
2041 
2042  if (B->isAssignmentOp()) {
2043  if (asc.alwaysAdd(*this, B)) {
2044  autoCreateBlock();
2045  appendStmt(Block, B);
2046  }
2047  Visit(B->getLHS());
2048  return Visit(B->getRHS());
2049  }
2050 
2051  if (asc.alwaysAdd(*this, B)) {
2052  autoCreateBlock();
2053  appendStmt(Block, B);
2054  }
2055 
2056  CFGBlock *RBlock = Visit(B->getRHS());
2057  CFGBlock *LBlock = Visit(B->getLHS());
2058  // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr
2059  // containing a DoStmt, and the LHS doesn't create a new block, then we should
2060  // return RBlock. Otherwise we'll incorrectly return NULL.
2061  return (LBlock ? LBlock : RBlock);
2062 }
2063 
2064 CFGBlock *CFGBuilder::VisitNoRecurse(Expr *E, AddStmtChoice asc) {
2065  if (asc.alwaysAdd(*this, E)) {
2066  autoCreateBlock();
2067  appendStmt(Block, E);
2068  }
2069  return Block;
2070 }
2071 
2072 CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) {
2073  // "break" is a control-flow statement. Thus we stop processing the current
2074  // block.
2075  if (badCFG)
2076  return nullptr;
2077 
2078  // Now create a new block that ends with the break statement.
2079  Block = createBlock(false);
2080  Block->setTerminator(B);
2081 
2082  // If there is no target for the break, then we are looking at an incomplete
2083  // AST. This means that the CFG cannot be constructed.
2084  if (BreakJumpTarget.block) {
2085  addAutomaticObjHandling(ScopePos, BreakJumpTarget.scopePosition, B);
2086  addSuccessor(Block, BreakJumpTarget.block);
2087  } else
2088  badCFG = true;
2089 
2090  return Block;
2091 }
2092 
2093 static bool CanThrow(Expr *E, ASTContext &Ctx) {
2094  QualType Ty = E->getType();
2095  if (Ty->isFunctionPointerType())
2096  Ty = Ty->getAs<PointerType>()->getPointeeType();
2097  else if (Ty->isBlockPointerType())
2098  Ty = Ty->getAs<BlockPointerType>()->getPointeeType();
2099 
2100  const FunctionType *FT = Ty->getAs<FunctionType>();
2101  if (FT) {
2102  if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT))
2103  if (!isUnresolvedExceptionSpec(Proto->getExceptionSpecType()) &&
2104  Proto->isNothrow(Ctx))
2105  return false;
2106  }
2107  return true;
2108 }
2109 
2110 CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) {
2111  // Compute the callee type.
2112  QualType calleeType = C->getCallee()->getType();
2113  if (calleeType == Context->BoundMemberTy) {
2114  QualType boundType = Expr::findBoundMemberType(C->getCallee());
2115 
2116  // We should only get a null bound type if processing a dependent
2117  // CFG. Recover by assuming nothing.
2118  if (!boundType.isNull()) calleeType = boundType;
2119  }
2120 
2121  // If this is a call to a no-return function, this stops the block here.
2122  bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn();
2123 
2124  bool AddEHEdge = false;
2125 
2126  // Languages without exceptions are assumed to not throw.
2127  if (Context->getLangOpts().Exceptions) {
2128  if (BuildOpts.AddEHEdges)
2129  AddEHEdge = true;
2130  }
2131 
2132  // If this is a call to a builtin function, it might not actually evaluate
2133  // its arguments. Don't add them to the CFG if this is the case.
2134  bool OmitArguments = false;
2135 
2136  if (FunctionDecl *FD = C->getDirectCallee()) {
2137  if (FD->isNoReturn() || C->isBuiltinAssumeFalse(*Context))
2138  NoReturn = true;
2139  if (FD->hasAttr<NoThrowAttr>())
2140  AddEHEdge = false;
2141  if (FD->getBuiltinID() == Builtin::BI__builtin_object_size)
2142  OmitArguments = true;
2143  }
2144 
2145  if (!CanThrow(C->getCallee(), *Context))
2146  AddEHEdge = false;
2147 
2148  if (OmitArguments) {
2149  assert(!NoReturn && "noreturn calls with unevaluated args not implemented");
2150  assert(!AddEHEdge && "EH calls with unevaluated args not implemented");
2151  autoCreateBlock();
2152  appendStmt(Block, C);
2153  return Visit(C->getCallee());
2154  }
2155 
2156  if (!NoReturn && !AddEHEdge) {
2157  return VisitStmt(C, asc.withAlwaysAdd(true));
2158  }
2159 
2160  if (Block) {
2161  Succ = Block;
2162  if (badCFG)
2163  return nullptr;
2164  }
2165 
2166  if (NoReturn)
2167  Block = createNoReturnBlock();
2168  else
2169  Block = createBlock();
2170 
2171  appendStmt(Block, C);
2172 
2173  if (AddEHEdge) {
2174  // Add exceptional edges.
2175  if (TryTerminatedBlock)
2176  addSuccessor(Block, TryTerminatedBlock);
2177  else
2178  addSuccessor(Block, &cfg->getExit());
2179  }
2180 
2181  return VisitChildren(C);
2182 }
2183 
2184 CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C,
2185  AddStmtChoice asc) {
2186  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2187  appendStmt(ConfluenceBlock, C);
2188  if (badCFG)
2189  return nullptr;
2190 
2191  AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2192  Succ = ConfluenceBlock;
2193  Block = nullptr;
2194  CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd);
2195  if (badCFG)
2196  return nullptr;
2197 
2198  Succ = ConfluenceBlock;
2199  Block = nullptr;
2200  CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd);
2201  if (badCFG)
2202  return nullptr;
2203 
2204  Block = createBlock(false);
2205  // See if this is a known constant.
2206  const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2207  addSuccessor(Block, KnownVal.isFalse() ? nullptr : LHSBlock);
2208  addSuccessor(Block, KnownVal.isTrue() ? nullptr : RHSBlock);
2209  Block->setTerminator(C);
2210  return addStmt(C->getCond());
2211 }
2212 
2213 CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) {
2214  LocalScope::const_iterator scopeBeginPos = ScopePos;
2215  addLocalScopeForStmt(C);
2216 
2217  if (!C->body_empty() && !isa<ReturnStmt>(*C->body_rbegin())) {
2218  // If the body ends with a ReturnStmt, the dtors will be added in
2219  // VisitReturnStmt.
2220  addAutomaticObjHandling(ScopePos, scopeBeginPos, C);
2221  }
2222 
2223  CFGBlock *LastBlock = Block;
2224 
2226  I != E; ++I ) {
2227  // If we hit a segment of code just containing ';' (NullStmts), we can
2228  // get a null block back. In such cases, just use the LastBlock
2229  if (CFGBlock *newBlock = addStmt(*I))
2230  LastBlock = newBlock;
2231 
2232  if (badCFG)
2233  return nullptr;
2234  }
2235 
2236  return LastBlock;
2237 }
2238 
2239 CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C,
2240  AddStmtChoice asc) {
2241  const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C);
2242  const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : nullptr);
2243 
2244  // Create the confluence block that will "merge" the results of the ternary
2245  // expression.
2246  CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2247  appendStmt(ConfluenceBlock, C);
2248  if (badCFG)
2249  return nullptr;
2250 
2251  AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2252 
2253  // Create a block for the LHS expression if there is an LHS expression. A
2254  // GCC extension allows LHS to be NULL, causing the condition to be the
2255  // value that is returned instead.
2256  // e.g: x ?: y is shorthand for: x ? x : y;
2257  Succ = ConfluenceBlock;
2258  Block = nullptr;
2259  CFGBlock *LHSBlock = nullptr;
2260  const Expr *trueExpr = C->getTrueExpr();
2261  if (trueExpr != opaqueValue) {
2262  LHSBlock = Visit(C->getTrueExpr(), alwaysAdd);
2263  if (badCFG)
2264  return nullptr;
2265  Block = nullptr;
2266  }
2267  else
2268  LHSBlock = ConfluenceBlock;
2269 
2270  // Create the block for the RHS expression.
2271  Succ = ConfluenceBlock;
2272  CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd);
2273  if (badCFG)
2274  return nullptr;
2275 
2276  // If the condition is a logical '&&' or '||', build a more accurate CFG.
2277  if (BinaryOperator *Cond =
2278  dyn_cast<BinaryOperator>(C->getCond()->IgnoreParens()))
2279  if (Cond->isLogicalOp())
2280  return VisitLogicalOperator(Cond, C, LHSBlock, RHSBlock).first;
2281 
2282  // Create the block that will contain the condition.
2283  Block = createBlock(false);
2284 
2285  // See if this is a known constant.
2286  const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2287  addSuccessor(Block, LHSBlock, !KnownVal.isFalse());
2288  addSuccessor(Block, RHSBlock, !KnownVal.isTrue());
2289  Block->setTerminator(C);
2290  Expr *condExpr = C->getCond();
2291 
2292  if (opaqueValue) {
2293  // Run the condition expression if it's not trivially expressed in
2294  // terms of the opaque value (or if there is no opaque value).
2295  if (condExpr != opaqueValue)
2296  addStmt(condExpr);
2297 
2298  // Before that, run the common subexpression if there was one.
2299  // At least one of this or the above will be run.
2300  return addStmt(BCO->getCommon());
2301  }
2302 
2303  return addStmt(condExpr);
2304 }
2305 
2306 CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) {
2307  // Check if the Decl is for an __label__. If so, elide it from the
2308  // CFG entirely.
2309  if (isa<LabelDecl>(*DS->decl_begin()))
2310  return Block;
2311 
2312  // This case also handles static_asserts.
2313  if (DS->isSingleDecl())
2314  return VisitDeclSubExpr(DS);
2315 
2316  CFGBlock *B = nullptr;
2317 
2318  // Build an individual DeclStmt for each decl.
2320  E = DS->decl_rend();
2321  I != E; ++I) {
2322  // Get the alignment of the new DeclStmt, padding out to >=8 bytes.
2323  unsigned A = alignof(DeclStmt) < 8 ? 8 : alignof(DeclStmt);
2324 
2325  // Allocate the DeclStmt using the BumpPtrAllocator. It will get
2326  // automatically freed with the CFG.
2327  DeclGroupRef DG(*I);
2328  Decl *D = *I;
2329  void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A);
2330  DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D));
2331  cfg->addSyntheticDeclStmt(DSNew, DS);
2332 
2333  // Append the fake DeclStmt to block.
2334  B = VisitDeclSubExpr(DSNew);
2335  }
2336 
2337  return B;
2338 }
2339 
2340 /// VisitDeclSubExpr - Utility method to add block-level expressions for
2341 /// DeclStmts and initializers in them.
2342 CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) {
2343  assert(DS->isSingleDecl() && "Can handle single declarations only.");
2344  VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl());
2345 
2346  if (!VD) {
2347  // Of everything that can be declared in a DeclStmt, only VarDecls impact
2348  // runtime semantics.
2349  return Block;
2350  }
2351 
2352  bool HasTemporaries = false;
2353 
2354  // Guard static initializers under a branch.
2355  CFGBlock *blockAfterStaticInit = nullptr;
2356 
2357  if (BuildOpts.AddStaticInitBranches && VD->isStaticLocal()) {
2358  // For static variables, we need to create a branch to track
2359  // whether or not they are initialized.
2360  if (Block) {
2361  Succ = Block;
2362  Block = nullptr;
2363  if (badCFG)
2364  return nullptr;
2365  }
2366  blockAfterStaticInit = Succ;
2367  }
2368 
2369  // Destructors of temporaries in initialization expression should be called
2370  // after initialization finishes.
2371  Expr *Init = VD->getInit();
2372  if (Init) {
2373  HasTemporaries = isa<ExprWithCleanups>(Init);
2374 
2375  if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
2376  // Generate destructors for temporaries in initialization expression.
2377  TempDtorContext Context;
2378  VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
2379  /*BindToTemporary=*/false, Context);
2380  }
2381  }
2382 
2383  autoCreateBlock();
2384  appendStmt(Block, DS);
2385 
2386  EnterConstructionContextIfNecessary(DS, Init);
2387 
2388  // Keep track of the last non-null block, as 'Block' can be nulled out
2389  // if the initializer expression is something like a 'while' in a
2390  // statement-expression.
2391  CFGBlock *LastBlock = Block;
2392 
2393  if (Init) {
2394  if (HasTemporaries) {
2395  // For expression with temporaries go directly to subexpression to omit
2396  // generating destructors for the second time.
2397  ExprWithCleanups *EC = cast<ExprWithCleanups>(Init);
2398  if (CFGBlock *newBlock = Visit(EC->getSubExpr()))
2399  LastBlock = newBlock;
2400  }
2401  else {
2402  if (CFGBlock *newBlock = Visit(Init))
2403  LastBlock = newBlock;
2404  }
2405  }
2406 
2407  // If the type of VD is a VLA, then we must process its size expressions.
2408  for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr());
2409  VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr())) {
2410  if (CFGBlock *newBlock = addStmt(VA->getSizeExpr()))
2411  LastBlock = newBlock;
2412  }
2413 
2414  // Remove variable from local scope.
2415  if (ScopePos && VD == *ScopePos)
2416  ++ScopePos;
2417 
2418  CFGBlock *B = LastBlock;
2419  if (blockAfterStaticInit) {
2420  Succ = B;
2421  Block = createBlock(false);
2422  Block->setTerminator(DS);
2423  addSuccessor(Block, blockAfterStaticInit);
2424  addSuccessor(Block, B);
2425  B = Block;
2426  }
2427 
2428  return B;
2429 }
2430 
2431 CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) {
2432  // We may see an if statement in the middle of a basic block, or it may be the
2433  // first statement we are processing. In either case, we create a new basic
2434  // block. First, we create the blocks for the then...else statements, and
2435  // then we create the block containing the if statement. If we were in the
2436  // middle of a block, we stop processing that block. That block is then the
2437  // implicit successor for the "then" and "else" clauses.
2438 
2439  // Save local scope position because in case of condition variable ScopePos
2440  // won't be restored when traversing AST.
2441  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2442 
2443  // Create local scope for C++17 if init-stmt if one exists.
2444  if (Stmt *Init = I->getInit())
2445  addLocalScopeForStmt(Init);
2446 
2447  // Create local scope for possible condition variable.
2448  // Store scope position. Add implicit destructor.
2449  if (VarDecl *VD = I->getConditionVariable())
2450  addLocalScopeForVarDecl(VD);
2451 
2452  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), I);
2453 
2454  // The block we were processing is now finished. Make it the successor
2455  // block.
2456  if (Block) {
2457  Succ = Block;
2458  if (badCFG)
2459  return nullptr;
2460  }
2461 
2462  // Process the false branch.
2463  CFGBlock *ElseBlock = Succ;
2464 
2465  if (Stmt *Else = I->getElse()) {
2466  SaveAndRestore<CFGBlock*> sv(Succ);
2467 
2468  // NULL out Block so that the recursive call to Visit will
2469  // create a new basic block.
2470  Block = nullptr;
2471 
2472  // If branch is not a compound statement create implicit scope
2473  // and add destructors.
2474  if (!isa<CompoundStmt>(Else))
2475  addLocalScopeAndDtors(Else);
2476 
2477  ElseBlock = addStmt(Else);
2478 
2479  if (!ElseBlock) // Can occur when the Else body has all NullStmts.
2480  ElseBlock = sv.get();
2481  else if (Block) {
2482  if (badCFG)
2483  return nullptr;
2484  }
2485  }
2486 
2487  // Process the true branch.
2488  CFGBlock *ThenBlock;
2489  {
2490  Stmt *Then = I->getThen();
2491  assert(Then);
2492  SaveAndRestore<CFGBlock*> sv(Succ);
2493  Block = nullptr;
2494 
2495  // If branch is not a compound statement create implicit scope
2496  // and add destructors.
2497  if (!isa<CompoundStmt>(Then))
2498  addLocalScopeAndDtors(Then);
2499 
2500  ThenBlock = addStmt(Then);
2501 
2502  if (!ThenBlock) {
2503  // We can reach here if the "then" body has all NullStmts.
2504  // Create an empty block so we can distinguish between true and false
2505  // branches in path-sensitive analyses.
2506  ThenBlock = createBlock(false);
2507  addSuccessor(ThenBlock, sv.get());
2508  } else if (Block) {
2509  if (badCFG)
2510  return nullptr;
2511  }
2512  }
2513 
2514  // Specially handle "if (expr1 || ...)" and "if (expr1 && ...)" by
2515  // having these handle the actual control-flow jump. Note that
2516  // if we introduce a condition variable, e.g. "if (int x = exp1 || exp2)"
2517  // we resort to the old control-flow behavior. This special handling
2518  // removes infeasible paths from the control-flow graph by having the
2519  // control-flow transfer of '&&' or '||' go directly into the then/else
2520  // blocks directly.
2521  BinaryOperator *Cond =
2523  ? nullptr
2524  : dyn_cast<BinaryOperator>(I->getCond()->IgnoreParens());
2525  CFGBlock *LastBlock;
2526  if (Cond && Cond->isLogicalOp())
2527  LastBlock = VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first;
2528  else {
2529  // Now create a new block containing the if statement.
2530  Block = createBlock(false);
2531 
2532  // Set the terminator of the new block to the If statement.
2533  Block->setTerminator(I);
2534 
2535  // See if this is a known constant.
2536  const TryResult &KnownVal = tryEvaluateBool(I->getCond());
2537 
2538  // Add the successors. If we know that specific branches are
2539  // unreachable, inform addSuccessor() of that knowledge.
2540  addSuccessor(Block, ThenBlock, /* isReachable = */ !KnownVal.isFalse());
2541  addSuccessor(Block, ElseBlock, /* isReachable = */ !KnownVal.isTrue());
2542 
2543  // Add the condition as the last statement in the new block. This may
2544  // create new blocks as the condition may contain control-flow. Any newly
2545  // created blocks will be pointed to be "Block".
2546  LastBlock = addStmt(I->getCond());
2547 
2548  // If the IfStmt contains a condition variable, add it and its
2549  // initializer to the CFG.
2550  if (const DeclStmt* DS = I->getConditionVariableDeclStmt()) {
2551  autoCreateBlock();
2552  LastBlock = addStmt(const_cast<DeclStmt *>(DS));
2553  }
2554  }
2555 
2556  // Finally, if the IfStmt contains a C++17 init-stmt, add it to the CFG.
2557  if (Stmt *Init = I->getInit()) {
2558  autoCreateBlock();
2559  LastBlock = addStmt(Init);
2560  }
2561 
2562  return LastBlock;
2563 }
2564 
2565 CFGBlock *CFGBuilder::VisitReturnStmt(ReturnStmt *R) {
2566  // If we were in the middle of a block we stop processing that block.
2567  //
2568  // NOTE: If a "return" appears in the middle of a block, this means that the
2569  // code afterwards is DEAD (unreachable). We still keep a basic block
2570  // for that code; a simple "mark-and-sweep" from the entry block will be
2571  // able to report such dead blocks.
2572 
2573  // Create the new block.
2574  Block = createBlock(false);
2575 
2576  addAutomaticObjHandling(ScopePos, LocalScope::const_iterator(), R);
2577 
2578  EnterConstructionContextIfNecessary(R, R->getRetValue());
2579 
2580  // If the one of the destructors does not return, we already have the Exit
2581  // block as a successor.
2582  if (!Block->hasNoReturnElement())
2583  addSuccessor(Block, &cfg->getExit());
2584 
2585  // Add the return statement to the block. This may create new blocks if R
2586  // contains control-flow (short-circuit operations).
2587  return VisitStmt(R, AddStmtChoice::AlwaysAdd);
2588 }
2589 
2590 CFGBlock *CFGBuilder::VisitSEHExceptStmt(SEHExceptStmt *ES) {
2591  // SEHExceptStmt are treated like labels, so they are the first statement in a
2592  // block.
2593 
2594  // Save local scope position because in case of exception variable ScopePos
2595  // won't be restored when traversing AST.
2596  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2597 
2598  addStmt(ES->getBlock());
2599  CFGBlock *SEHExceptBlock = Block;
2600  if (!SEHExceptBlock)
2601  SEHExceptBlock = createBlock();
2602 
2603  appendStmt(SEHExceptBlock, ES);
2604 
2605  // Also add the SEHExceptBlock as a label, like with regular labels.
2606  SEHExceptBlock->setLabel(ES);
2607 
2608  // Bail out if the CFG is bad.
2609  if (badCFG)
2610  return nullptr;
2611 
2612  // We set Block to NULL to allow lazy creation of a new block (if necessary).
2613  Block = nullptr;
2614 
2615  return SEHExceptBlock;
2616 }
2617 
2618 CFGBlock *CFGBuilder::VisitSEHFinallyStmt(SEHFinallyStmt *FS) {
2619  return VisitCompoundStmt(FS->getBlock());
2620 }
2621 
2622 CFGBlock *CFGBuilder::VisitSEHLeaveStmt(SEHLeaveStmt *LS) {
2623  // "__leave" is a control-flow statement. Thus we stop processing the current
2624  // block.
2625  if (badCFG)
2626  return nullptr;
2627 
2628  // Now create a new block that ends with the __leave statement.
2629  Block = createBlock(false);
2630  Block->setTerminator(LS);
2631 
2632  // If there is no target for the __leave, then we are looking at an incomplete
2633  // AST. This means that the CFG cannot be constructed.
2634  if (SEHLeaveJumpTarget.block) {
2635  addAutomaticObjHandling(ScopePos, SEHLeaveJumpTarget.scopePosition, LS);
2636  addSuccessor(Block, SEHLeaveJumpTarget.block);
2637  } else
2638  badCFG = true;
2639 
2640  return Block;
2641 }
2642 
2643 CFGBlock *CFGBuilder::VisitSEHTryStmt(SEHTryStmt *Terminator) {
2644  // "__try"/"__except"/"__finally" is a control-flow statement. Thus we stop
2645  // processing the current block.
2646  CFGBlock *SEHTrySuccessor = nullptr;
2647 
2648  if (Block) {
2649  if (badCFG)
2650  return nullptr;
2651  SEHTrySuccessor = Block;
2652  } else SEHTrySuccessor = Succ;
2653 
2654  // FIXME: Implement __finally support.
2655  if (Terminator->getFinallyHandler())
2656  return NYS();
2657 
2658  CFGBlock *PrevSEHTryTerminatedBlock = TryTerminatedBlock;
2659 
2660  // Create a new block that will contain the __try statement.
2661  CFGBlock *NewTryTerminatedBlock = createBlock(false);
2662 
2663  // Add the terminator in the __try block.
2664  NewTryTerminatedBlock->setTerminator(Terminator);
2665 
2666  if (SEHExceptStmt *Except = Terminator->getExceptHandler()) {
2667  // The code after the try is the implicit successor if there's an __except.
2668  Succ = SEHTrySuccessor;
2669  Block = nullptr;
2670  CFGBlock *ExceptBlock = VisitSEHExceptStmt(Except);
2671  if (!ExceptBlock)
2672  return nullptr;
2673  // Add this block to the list of successors for the block with the try
2674  // statement.
2675  addSuccessor(NewTryTerminatedBlock, ExceptBlock);
2676  }
2677  if (PrevSEHTryTerminatedBlock)
2678  addSuccessor(NewTryTerminatedBlock, PrevSEHTryTerminatedBlock);
2679  else
2680  addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
2681 
2682  // The code after the try is the implicit successor.
2683  Succ = SEHTrySuccessor;
2684 
2685  // Save the current "__try" context.
2686  SaveAndRestore<CFGBlock *> save_try(TryTerminatedBlock,
2687  NewTryTerminatedBlock);
2688  cfg->addTryDispatchBlock(TryTerminatedBlock);
2689 
2690  // Save the current value for the __leave target.
2691  // All __leaves should go to the code following the __try
2692  // (FIXME: or if the __try has a __finally, to the __finally.)
2693  SaveAndRestore<JumpTarget> save_break(SEHLeaveJumpTarget);
2694  SEHLeaveJumpTarget = JumpTarget(SEHTrySuccessor, ScopePos);
2695 
2696  assert(Terminator->getTryBlock() && "__try must contain a non-NULL body");
2697  Block = nullptr;
2698  return addStmt(Terminator->getTryBlock());
2699 }
2700 
2701 CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) {
2702  // Get the block of the labeled statement. Add it to our map.
2703  addStmt(L->getSubStmt());
2704  CFGBlock *LabelBlock = Block;
2705 
2706  if (!LabelBlock) // This can happen when the body is empty, i.e.
2707  LabelBlock = createBlock(); // scopes that only contains NullStmts.
2708 
2709  assert(LabelMap.find(L->getDecl()) == LabelMap.end() &&
2710  "label already in map");
2711  LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos);
2712 
2713  // Labels partition blocks, so this is the end of the basic block we were
2714  // processing (L is the block's label). Because this is label (and we have
2715  // already processed the substatement) there is no extra control-flow to worry
2716  // about.
2717  LabelBlock->setLabel(L);
2718  if (badCFG)
2719  return nullptr;
2720 
2721  // We set Block to NULL to allow lazy creation of a new block (if necessary);
2722  Block = nullptr;
2723 
2724  // This block is now the implicit successor of other blocks.
2725  Succ = LabelBlock;
2726 
2727  return LabelBlock;
2728 }
2729 
2730 CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) {
2731  CFGBlock *LastBlock = VisitNoRecurse(E, asc);
2732  for (const BlockDecl::Capture &CI : E->getBlockDecl()->captures()) {
2733  if (Expr *CopyExpr = CI.getCopyExpr()) {
2734  CFGBlock *Tmp = Visit(CopyExpr);
2735  if (Tmp)
2736  LastBlock = Tmp;
2737  }
2738  }
2739  return LastBlock;
2740 }
2741 
2742 CFGBlock *CFGBuilder::VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc) {
2743  CFGBlock *LastBlock = VisitNoRecurse(E, asc);
2745  et = E->capture_init_end(); it != et; ++it) {
2746  if (Expr *Init = *it) {
2747  CFGBlock *Tmp = Visit(Init);
2748  if (Tmp)
2749  LastBlock = Tmp;
2750  }
2751  }
2752  return LastBlock;
2753 }
2754 
2755 CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) {
2756  // Goto is a control-flow statement. Thus we stop processing the current
2757  // block and create a new one.
2758 
2759  Block = createBlock(false);
2760  Block->setTerminator(G);
2761 
2762  // If we already know the mapping to the label block add the successor now.
2763  LabelMapTy::iterator I = LabelMap.find(G->getLabel());
2764 
2765  if (I == LabelMap.end())
2766  // We will need to backpatch this block later.
2767  BackpatchBlocks.push_back(JumpSource(Block, ScopePos));
2768  else {
2769  JumpTarget JT = I->second;
2770  addAutomaticObjHandling(ScopePos, JT.scopePosition, G);
2771  addSuccessor(Block, JT.block);
2772  }
2773 
2774  return Block;
2775 }
2776 
2777 CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) {
2778  CFGBlock *LoopSuccessor = nullptr;
2779 
2780  // Save local scope position because in case of condition variable ScopePos
2781  // won't be restored when traversing AST.
2782  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2783 
2784  // Create local scope for init statement and possible condition variable.
2785  // Add destructor for init statement and condition variable.
2786  // Store scope position for continue statement.
2787  if (Stmt *Init = F->getInit())
2788  addLocalScopeForStmt(Init);
2789  LocalScope::const_iterator LoopBeginScopePos = ScopePos;
2790 
2791  if (VarDecl *VD = F->getConditionVariable())
2792  addLocalScopeForVarDecl(VD);
2793  LocalScope::const_iterator ContinueScopePos = ScopePos;
2794 
2795  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), F);
2796 
2797  addLoopExit(F);
2798 
2799  // "for" is a control-flow statement. Thus we stop processing the current
2800  // block.
2801  if (Block) {
2802  if (badCFG)
2803  return nullptr;
2804  LoopSuccessor = Block;
2805  } else
2806  LoopSuccessor = Succ;
2807 
2808  // Save the current value for the break targets.
2809  // All breaks should go to the code following the loop.
2810  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
2811  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
2812 
2813  CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
2814 
2815  // Now create the loop body.
2816  {
2817  assert(F->getBody());
2818 
2819  // Save the current values for Block, Succ, continue and break targets.
2820  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
2821  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
2822 
2823  // Create an empty block to represent the transition block for looping back
2824  // to the head of the loop. If we have increment code, it will
2825  // go in this block as well.
2826  Block = Succ = TransitionBlock = createBlock(false);
2827  TransitionBlock->setLoopTarget(F);
2828 
2829  if (Stmt *I = F->getInc()) {
2830  // Generate increment code in its own basic block. This is the target of
2831  // continue statements.
2832  Succ = addStmt(I);
2833  }
2834 
2835  // Finish up the increment (or empty) block if it hasn't been already.
2836  if (Block) {
2837  assert(Block == Succ);
2838  if (badCFG)
2839  return nullptr;
2840  Block = nullptr;
2841  }
2842 
2843  // The starting block for the loop increment is the block that should
2844  // represent the 'loop target' for looping back to the start of the loop.
2845  ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
2846  ContinueJumpTarget.block->setLoopTarget(F);
2847 
2848  // Loop body should end with destructor of Condition variable (if any).
2849  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, F);
2850 
2851  // If body is not a compound statement create implicit scope
2852  // and add destructors.
2853  if (!isa<CompoundStmt>(F->getBody()))
2854  addLocalScopeAndDtors(F->getBody());
2855 
2856  // Now populate the body block, and in the process create new blocks as we
2857  // walk the body of the loop.
2858  BodyBlock = addStmt(F->getBody());
2859 
2860  if (!BodyBlock) {
2861  // In the case of "for (...;...;...);" we can have a null BodyBlock.
2862  // Use the continue jump target as the proxy for the body.
2863  BodyBlock = ContinueJumpTarget.block;
2864  }
2865  else if (badCFG)
2866  return nullptr;
2867  }
2868 
2869  // Because of short-circuit evaluation, the condition of the loop can span
2870  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
2871  // evaluate the condition.
2872  CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
2873 
2874  do {
2875  Expr *C = F->getCond();
2876 
2877  // Specially handle logical operators, which have a slightly
2878  // more optimal CFG representation.
2879  if (BinaryOperator *Cond =
2880  dyn_cast_or_null<BinaryOperator>(C ? C->IgnoreParens() : nullptr))
2881  if (Cond->isLogicalOp()) {
2882  std::tie(EntryConditionBlock, ExitConditionBlock) =
2883  VisitLogicalOperator(Cond, F, BodyBlock, LoopSuccessor);
2884  break;
2885  }
2886 
2887  // The default case when not handling logical operators.
2888  EntryConditionBlock = ExitConditionBlock = createBlock(false);
2889  ExitConditionBlock->setTerminator(F);
2890 
2891  // See if this is a known constant.
2892  TryResult KnownVal(true);
2893 
2894  if (C) {
2895  // Now add the actual condition to the condition block.
2896  // Because the condition itself may contain control-flow, new blocks may
2897  // be created. Thus we update "Succ" after adding the condition.
2898  Block = ExitConditionBlock;
2899  EntryConditionBlock = addStmt(C);
2900 
2901  // If this block contains a condition variable, add both the condition
2902  // variable and initializer to the CFG.
2903  if (VarDecl *VD = F->getConditionVariable()) {
2904  if (Expr *Init = VD->getInit()) {
2905  autoCreateBlock();
2906  appendStmt(Block, F->getConditionVariableDeclStmt());
2907  EntryConditionBlock = addStmt(Init);
2908  assert(Block == EntryConditionBlock);
2909  }
2910  }
2911 
2912  if (Block && badCFG)
2913  return nullptr;
2914 
2915  KnownVal = tryEvaluateBool(C);
2916  }
2917 
2918  // Add the loop body entry as a successor to the condition.
2919  addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
2920  // Link up the condition block with the code that follows the loop. (the
2921  // false branch).
2922  addSuccessor(ExitConditionBlock,
2923  KnownVal.isTrue() ? nullptr : LoopSuccessor);
2924  } while (false);
2925 
2926  // Link up the loop-back block to the entry condition block.
2927  addSuccessor(TransitionBlock, EntryConditionBlock);
2928 
2929  // The condition block is the implicit successor for any code above the loop.
2930  Succ = EntryConditionBlock;
2931 
2932  // If the loop contains initialization, create a new block for those
2933  // statements. This block can also contain statements that precede the loop.
2934  if (Stmt *I = F->getInit()) {
2935  Block = createBlock();
2936  return addStmt(I);
2937  }
2938 
2939  // There is no loop initialization. We are thus basically a while loop.
2940  // NULL out Block to force lazy block construction.
2941  Block = nullptr;
2942  Succ = EntryConditionBlock;
2943  return EntryConditionBlock;
2944 }
2945 
2946 CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) {
2947  if (asc.alwaysAdd(*this, M)) {
2948  autoCreateBlock();
2949  appendStmt(Block, M);
2950  }
2951  return Visit(M->getBase());
2952 }
2953 
2954 CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) {
2955  // Objective-C fast enumeration 'for' statements:
2956  // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC
2957  //
2958  // for ( Type newVariable in collection_expression ) { statements }
2959  //
2960  // becomes:
2961  //
2962  // prologue:
2963  // 1. collection_expression
2964  // T. jump to loop_entry
2965  // loop_entry:
2966  // 1. side-effects of element expression
2967  // 1. ObjCForCollectionStmt [performs binding to newVariable]
2968  // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil]
2969  // TB:
2970  // statements
2971  // T. jump to loop_entry
2972  // FB:
2973  // what comes after
2974  //
2975  // and
2976  //
2977  // Type existingItem;
2978  // for ( existingItem in expression ) { statements }
2979  //
2980  // becomes:
2981  //
2982  // the same with newVariable replaced with existingItem; the binding works
2983  // the same except that for one ObjCForCollectionStmt::getElement() returns
2984  // a DeclStmt and the other returns a DeclRefExpr.
2985 
2986  CFGBlock *LoopSuccessor = nullptr;
2987 
2988  if (Block) {
2989  if (badCFG)
2990  return nullptr;
2991  LoopSuccessor = Block;
2992  Block = nullptr;
2993  } else
2994  LoopSuccessor = Succ;
2995 
2996  // Build the condition blocks.
2997  CFGBlock *ExitConditionBlock = createBlock(false);
2998 
2999  // Set the terminator for the "exit" condition block.
3000  ExitConditionBlock->setTerminator(S);
3001 
3002  // The last statement in the block should be the ObjCForCollectionStmt, which
3003  // performs the actual binding to 'element' and determines if there are any
3004  // more items in the collection.
3005  appendStmt(ExitConditionBlock, S);
3006  Block = ExitConditionBlock;
3007 
3008  // Walk the 'element' expression to see if there are any side-effects. We
3009  // generate new blocks as necessary. We DON'T add the statement by default to
3010  // the CFG unless it contains control-flow.
3011  CFGBlock *EntryConditionBlock = Visit(S->getElement(),
3012  AddStmtChoice::NotAlwaysAdd);
3013  if (Block) {
3014  if (badCFG)
3015  return nullptr;
3016  Block = nullptr;
3017  }
3018 
3019  // The condition block is the implicit successor for the loop body as well as
3020  // any code above the loop.
3021  Succ = EntryConditionBlock;
3022 
3023  // Now create the true branch.
3024  {
3025  // Save the current values for Succ, continue and break targets.
3026  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3027  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3028  save_break(BreakJumpTarget);
3029 
3030  // Add an intermediate block between the BodyBlock and the
3031  // EntryConditionBlock to represent the "loop back" transition, for looping
3032  // back to the head of the loop.
3033  CFGBlock *LoopBackBlock = nullptr;
3034  Succ = LoopBackBlock = createBlock();
3035  LoopBackBlock->setLoopTarget(S);
3036 
3037  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3038  ContinueJumpTarget = JumpTarget(Succ, ScopePos);
3039 
3040  CFGBlock *BodyBlock = addStmt(S->getBody());
3041 
3042  if (!BodyBlock)
3043  BodyBlock = ContinueJumpTarget.block; // can happen for "for (X in Y) ;"
3044  else if (Block) {
3045  if (badCFG)
3046  return nullptr;
3047  }
3048 
3049  // This new body block is a successor to our "exit" condition block.
3050  addSuccessor(ExitConditionBlock, BodyBlock);
3051  }
3052 
3053  // Link up the condition block with the code that follows the loop.
3054  // (the false branch).
3055  addSuccessor(ExitConditionBlock, LoopSuccessor);
3056 
3057  // Now create a prologue block to contain the collection expression.
3058  Block = createBlock();
3059  return addStmt(S->getCollection());
3060 }
3061 
3062 CFGBlock *CFGBuilder::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) {
3063  // Inline the body.
3064  return addStmt(S->getSubStmt());
3065  // TODO: consider adding cleanups for the end of @autoreleasepool scope.
3066 }
3067 
3068 CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) {
3069  // FIXME: Add locking 'primitives' to CFG for @synchronized.
3070 
3071  // Inline the body.
3072  CFGBlock *SyncBlock = addStmt(S->getSynchBody());
3073 
3074  // The sync body starts its own basic block. This makes it a little easier
3075  // for diagnostic clients.
3076  if (SyncBlock) {
3077  if (badCFG)
3078  return nullptr;
3079 
3080  Block = nullptr;
3081  Succ = SyncBlock;
3082  }
3083 
3084  // Add the @synchronized to the CFG.
3085  autoCreateBlock();
3086  appendStmt(Block, S);
3087 
3088  // Inline the sync expression.
3089  return addStmt(S->getSynchExpr());
3090 }
3091 
3092 CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) {
3093  // FIXME
3094  return NYS();
3095 }
3096 
3097 CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) {
3098  autoCreateBlock();
3099 
3100  // Add the PseudoObject as the last thing.
3101  appendStmt(Block, E);
3102 
3103  CFGBlock *lastBlock = Block;
3104 
3105  // Before that, evaluate all of the semantics in order. In
3106  // CFG-land, that means appending them in reverse order.
3107  for (unsigned i = E->getNumSemanticExprs(); i != 0; ) {
3108  Expr *Semantic = E->getSemanticExpr(--i);
3109 
3110  // If the semantic is an opaque value, we're being asked to bind
3111  // it to its source expression.
3112  if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
3113  Semantic = OVE->getSourceExpr();
3114 
3115  if (CFGBlock *B = Visit(Semantic))
3116  lastBlock = B;
3117  }
3118 
3119  return lastBlock;
3120 }
3121 
3122 CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) {
3123  CFGBlock *LoopSuccessor = nullptr;
3124 
3125  // Save local scope position because in case of condition variable ScopePos
3126  // won't be restored when traversing AST.
3127  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3128 
3129  // Create local scope for possible condition variable.
3130  // Store scope position for continue statement.
3131  LocalScope::const_iterator LoopBeginScopePos = ScopePos;
3132  if (VarDecl *VD = W->getConditionVariable()) {
3133  addLocalScopeForVarDecl(VD);
3134  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3135  }
3136  addLoopExit(W);
3137 
3138  // "while" is a control-flow statement. Thus we stop processing the current
3139  // block.
3140  if (Block) {
3141  if (badCFG)
3142  return nullptr;
3143  LoopSuccessor = Block;
3144  Block = nullptr;
3145  } else {
3146  LoopSuccessor = Succ;
3147  }
3148 
3149  CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
3150 
3151  // Process the loop body.
3152  {
3153  assert(W->getBody());
3154 
3155  // Save the current values for Block, Succ, continue and break targets.
3156  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3157  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3158  save_break(BreakJumpTarget);
3159 
3160  // Create an empty block to represent the transition block for looping back
3161  // to the head of the loop.
3162  Succ = TransitionBlock = createBlock(false);
3163  TransitionBlock->setLoopTarget(W);
3164  ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos);
3165 
3166  // All breaks should go to the code following the loop.
3167  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3168 
3169  // Loop body should end with destructor of Condition variable (if any).
3170  addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3171 
3172  // If body is not a compound statement create implicit scope
3173  // and add destructors.
3174  if (!isa<CompoundStmt>(W->getBody()))
3175  addLocalScopeAndDtors(W->getBody());
3176 
3177  // Create the body. The returned block is the entry to the loop body.
3178  BodyBlock = addStmt(W->getBody());
3179 
3180  if (!BodyBlock)
3181  BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;"
3182  else if (Block && badCFG)
3183  return nullptr;
3184  }
3185 
3186  // Because of short-circuit evaluation, the condition of the loop can span
3187  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3188  // evaluate the condition.
3189  CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
3190 
3191  do {
3192  Expr *C = W->getCond();
3193 
3194  // Specially handle logical operators, which have a slightly
3195  // more optimal CFG representation.
3196  if (BinaryOperator *Cond = dyn_cast<BinaryOperator>(C->IgnoreParens()))
3197  if (Cond->isLogicalOp()) {
3198  std::tie(EntryConditionBlock, ExitConditionBlock) =
3199  VisitLogicalOperator(Cond, W, BodyBlock, LoopSuccessor);
3200  break;
3201  }
3202 
3203  // The default case when not handling logical operators.
3204  ExitConditionBlock = createBlock(false);
3205  ExitConditionBlock->setTerminator(W);
3206 
3207  // Now add the actual condition to the condition block.
3208  // Because the condition itself may contain control-flow, new blocks may
3209  // be created. Thus we update "Succ" after adding the condition.
3210  Block = ExitConditionBlock;
3211  Block = EntryConditionBlock = addStmt(C);
3212 
3213  // If this block contains a condition variable, add both the condition
3214  // variable and initializer to the CFG.
3215  if (VarDecl *VD = W->getConditionVariable()) {
3216  if (Expr *Init = VD->getInit()) {
3217  autoCreateBlock();
3218  appendStmt(Block, W->getConditionVariableDeclStmt());
3219  EntryConditionBlock = addStmt(Init);
3220  assert(Block == EntryConditionBlock);
3221  }
3222  }
3223 
3224  if (Block && badCFG)
3225  return nullptr;
3226 
3227  // See if this is a known constant.
3228  const TryResult& KnownVal = tryEvaluateBool(C);
3229 
3230  // Add the loop body entry as a successor to the condition.
3231  addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
3232  // Link up the condition block with the code that follows the loop. (the
3233  // false branch).
3234  addSuccessor(ExitConditionBlock,
3235  KnownVal.isTrue() ? nullptr : LoopSuccessor);
3236  } while(false);
3237 
3238  // Link up the loop-back block to the entry condition block.
3239  addSuccessor(TransitionBlock, EntryConditionBlock);
3240 
3241  // There can be no more statements in the condition block since we loop back
3242  // to this block. NULL out Block to force lazy creation of another block.
3243  Block = nullptr;
3244 
3245  // Return the condition block, which is the dominating block for the loop.
3246  Succ = EntryConditionBlock;
3247  return EntryConditionBlock;
3248 }
3249 
3250 CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) {
3251  // FIXME: For now we pretend that @catch and the code it contains does not
3252  // exit.
3253  return Block;
3254 }
3255 
3256 CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) {
3257  // FIXME: This isn't complete. We basically treat @throw like a return
3258  // statement.
3259 
3260  // If we were in the middle of a block we stop processing that block.
3261  if (badCFG)
3262  return nullptr;
3263 
3264  // Create the new block.
3265  Block = createBlock(false);
3266 
3267  // The Exit block is the only successor.
3268  addSuccessor(Block, &cfg->getExit());
3269 
3270  // Add the statement to the block. This may create new blocks if S contains
3271  // control-flow (short-circuit operations).
3272  return VisitStmt(S, AddStmtChoice::AlwaysAdd);
3273 }
3274 
3275 CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) {
3276  // If we were in the middle of a block we stop processing that block.
3277  if (badCFG)
3278  return nullptr;
3279 
3280  // Create the new block.
3281  Block = createBlock(false);
3282 
3283  if (TryTerminatedBlock)
3284  // The current try statement is the only successor.
3285  addSuccessor(Block, TryTerminatedBlock);
3286  else
3287  // otherwise the Exit block is the only successor.
3288  addSuccessor(Block, &cfg->getExit());
3289 
3290  // Add the statement to the block. This may create new blocks if S contains
3291  // control-flow (short-circuit operations).
3292  return VisitStmt(T, AddStmtChoice::AlwaysAdd);
3293 }
3294 
3295 CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) {
3296  CFGBlock *LoopSuccessor = nullptr;
3297 
3298  addLoopExit(D);
3299 
3300  // "do...while" is a control-flow statement. Thus we stop processing the
3301  // current block.
3302  if (Block) {
3303  if (badCFG)
3304  return nullptr;
3305  LoopSuccessor = Block;
3306  } else
3307  LoopSuccessor = Succ;
3308 
3309  // Because of short-circuit evaluation, the condition of the loop can span
3310  // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3311  // evaluate the condition.
3312  CFGBlock *ExitConditionBlock = createBlock(false);
3313  CFGBlock *EntryConditionBlock = ExitConditionBlock;
3314 
3315  // Set the terminator for the "exit" condition block.
3316  ExitConditionBlock->setTerminator(D);
3317 
3318  // Now add the actual condition to the condition block. Because the condition
3319  // itself may contain control-flow, new blocks may be created.
3320  if (Stmt *C = D->getCond()) {
3321  Block = ExitConditionBlock;
3322  EntryConditionBlock = addStmt(C);
3323  if (Block) {
3324  if (badCFG)
3325  return nullptr;
3326  }
3327  }
3328 
3329  // The condition block is the implicit successor for the loop body.
3330  Succ = EntryConditionBlock;
3331 
3332  // See if this is a known constant.
3333  const TryResult &KnownVal = tryEvaluateBool(D->getCond());
3334 
3335  // Process the loop body.
3336  CFGBlock *BodyBlock = nullptr;
3337  {
3338  assert(D->getBody());
3339 
3340  // Save the current values for Block, Succ, and continue and break targets
3341  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3342  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3343  save_break(BreakJumpTarget);
3344 
3345  // All continues within this loop should go to the condition block
3346  ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos);
3347 
3348  // All breaks should go to the code following the loop.
3349  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3350 
3351  // NULL out Block to force lazy instantiation of blocks for the body.
3352  Block = nullptr;
3353 
3354  // If body is not a compound statement create implicit scope
3355  // and add destructors.
3356  if (!isa<CompoundStmt>(D->getBody()))
3357  addLocalScopeAndDtors(D->getBody());
3358 
3359  // Create the body. The returned block is the entry to the loop body.
3360  BodyBlock = addStmt(D->getBody());
3361 
3362  if (!BodyBlock)
3363  BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)"
3364  else if (Block) {
3365  if (badCFG)
3366  return nullptr;
3367  }
3368 
3369  // Add an intermediate block between the BodyBlock and the
3370  // ExitConditionBlock to represent the "loop back" transition. Create an
3371  // empty block to represent the transition block for looping back to the
3372  // head of the loop.
3373  // FIXME: Can we do this more efficiently without adding another block?
3374  Block = nullptr;
3375  Succ = BodyBlock;
3376  CFGBlock *LoopBackBlock = createBlock();
3377  LoopBackBlock->setLoopTarget(D);
3378 
3379  if (!KnownVal.isFalse())
3380  // Add the loop body entry as a successor to the condition.
3381  addSuccessor(ExitConditionBlock, LoopBackBlock);
3382  else
3383  addSuccessor(ExitConditionBlock, nullptr);
3384  }
3385 
3386  // Link up the condition block with the code that follows the loop.
3387  // (the false branch).
3388  addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
3389 
3390  // There can be no more statements in the body block(s) since we loop back to
3391  // the body. NULL out Block to force lazy creation of another block.
3392  Block = nullptr;
3393 
3394  // Return the loop body, which is the dominating block for the loop.
3395  Succ = BodyBlock;
3396  return BodyBlock;
3397 }
3398 
3399 CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) {
3400  // "continue" is a control-flow statement. Thus we stop processing the
3401  // current block.
3402  if (badCFG)
3403  return nullptr;
3404 
3405  // Now create a new block that ends with the continue statement.
3406  Block = createBlock(false);
3407  Block->setTerminator(C);
3408 
3409  // If there is no target for the continue, then we are looking at an
3410  // incomplete AST. This means the CFG cannot be constructed.
3411  if (ContinueJumpTarget.block) {
3412  addAutomaticObjHandling(ScopePos, ContinueJumpTarget.scopePosition, C);
3413  addSuccessor(Block, ContinueJumpTarget.block);
3414  } else
3415  badCFG = true;
3416 
3417  return Block;
3418 }
3419 
3420 CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
3421  AddStmtChoice asc) {
3422  if (asc.alwaysAdd(*this, E)) {
3423  autoCreateBlock();
3424  appendStmt(Block, E);
3425  }
3426 
3427  // VLA types have expressions that must be evaluated.
3428  CFGBlock *lastBlock = Block;
3429 
3430  if (E->isArgumentType()) {
3431  for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr());
3432  VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr()))
3433  lastBlock = addStmt(VA->getSizeExpr());
3434  }
3435  return lastBlock;
3436 }
3437 
3438 /// VisitStmtExpr - Utility method to handle (nested) statement
3439 /// expressions (a GCC extension).
3440 CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) {
3441  if (asc.alwaysAdd(*this, SE)) {
3442  autoCreateBlock();
3443  appendStmt(Block, SE);
3444  }
3445  return VisitCompoundStmt(SE->getSubStmt());
3446 }
3447 
3448 CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) {
3449  // "switch" is a control-flow statement. Thus we stop processing the current
3450  // block.
3451  CFGBlock *SwitchSuccessor = nullptr;
3452 
3453  // Save local scope position because in case of condition variable ScopePos
3454  // won't be restored when traversing AST.
3455  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3456 
3457  // Create local scope for C++17 switch init-stmt if one exists.
3458  if (Stmt *Init = Terminator->getInit())
3459  addLocalScopeForStmt(Init);
3460 
3461  // Create local scope for possible condition variable.
3462  // Store scope position. Add implicit destructor.
3463  if (VarDecl *VD = Terminator->getConditionVariable())
3464  addLocalScopeForVarDecl(VD);
3465 
3466  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), Terminator);
3467 
3468  if (Block) {
3469  if (badCFG)
3470  return nullptr;
3471  SwitchSuccessor = Block;
3472  } else SwitchSuccessor = Succ;
3473 
3474  // Save the current "switch" context.
3475  SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock),
3476  save_default(DefaultCaseBlock);
3477  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3478 
3479  // Set the "default" case to be the block after the switch statement. If the
3480  // switch statement contains a "default:", this value will be overwritten with
3481  // the block for that code.
3482  DefaultCaseBlock = SwitchSuccessor;
3483 
3484  // Create a new block that will contain the switch statement.
3485  SwitchTerminatedBlock = createBlock(false);
3486 
3487  // Now process the switch body. The code after the switch is the implicit
3488  // successor.
3489  Succ = SwitchSuccessor;
3490  BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos);
3491 
3492  // When visiting the body, the case statements should automatically get linked
3493  // up to the switch. We also don't keep a pointer to the body, since all
3494  // control-flow from the switch goes to case/default statements.
3495  assert(Terminator->getBody() && "switch must contain a non-NULL body");
3496  Block = nullptr;
3497 
3498  // For pruning unreachable case statements, save the current state
3499  // for tracking the condition value.
3500  SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered,
3501  false);
3502 
3503  // Determine if the switch condition can be explicitly evaluated.
3504  assert(Terminator->getCond() && "switch condition must be non-NULL");
3505  Expr::EvalResult result;
3506  bool b = tryEvaluate(Terminator->getCond(), result);
3507  SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond,
3508  b ? &result : nullptr);
3509 
3510  // If body is not a compound statement create implicit scope
3511  // and add destructors.
3512  if (!isa<CompoundStmt>(Terminator->getBody()))
3513  addLocalScopeAndDtors(Terminator->getBody());
3514 
3515  addStmt(Terminator->getBody());
3516  if (Block) {
3517  if (badCFG)
3518  return nullptr;
3519  }
3520 
3521  // If we have no "default:" case, the default transition is to the code
3522  // following the switch body. Moreover, take into account if all the
3523  // cases of a switch are covered (e.g., switching on an enum value).
3524  //
3525  // Note: We add a successor to a switch that is considered covered yet has no
3526  // case statements if the enumeration has no enumerators.
3527  bool SwitchAlwaysHasSuccessor = false;
3528  SwitchAlwaysHasSuccessor |= switchExclusivelyCovered;
3529  SwitchAlwaysHasSuccessor |= Terminator->isAllEnumCasesCovered() &&
3530  Terminator->getSwitchCaseList();
3531  addSuccessor(SwitchTerminatedBlock, DefaultCaseBlock,
3532  !SwitchAlwaysHasSuccessor);
3533 
3534  // Add the terminator and condition in the switch block.
3535  SwitchTerminatedBlock->setTerminator(Terminator);
3536  Block = SwitchTerminatedBlock;
3537  CFGBlock *LastBlock = addStmt(Terminator->getCond());
3538 
3539  // If the SwitchStmt contains a condition variable, add both the
3540  // SwitchStmt and the condition variable initialization to the CFG.
3541  if (VarDecl *VD = Terminator->getConditionVariable()) {
3542  if (Expr *Init = VD->getInit()) {
3543  autoCreateBlock();
3544  appendStmt(Block, Terminator->getConditionVariableDeclStmt());
3545  LastBlock = addStmt(Init);
3546  }
3547  }
3548 
3549  // Finally, if the SwitchStmt contains a C++17 init-stmt, add it to the CFG.
3550  if (Stmt *Init = Terminator->getInit()) {
3551  autoCreateBlock();
3552  LastBlock = addStmt(Init);
3553  }
3554 
3555  return LastBlock;
3556 }
3557 
3558 static bool shouldAddCase(bool &switchExclusivelyCovered,
3559  const Expr::EvalResult *switchCond,
3560  const CaseStmt *CS,
3561  ASTContext &Ctx) {
3562  if (!switchCond)
3563  return true;
3564 
3565  bool addCase = false;
3566 
3567  if (!switchExclusivelyCovered) {
3568  if (switchCond->Val.isInt()) {
3569  // Evaluate the LHS of the case value.
3570  const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx);
3571  const llvm::APSInt &condInt = switchCond->Val.getInt();
3572 
3573  if (condInt == lhsInt) {
3574  addCase = true;
3575  switchExclusivelyCovered = true;
3576  }
3577  else if (condInt > lhsInt) {
3578  if (const Expr *RHS = CS->getRHS()) {
3579  // Evaluate the RHS of the case value.
3580  const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx);
3581  if (V2 >= condInt) {
3582  addCase = true;
3583  switchExclusivelyCovered = true;
3584  }
3585  }
3586  }
3587  }
3588  else
3589  addCase = true;
3590  }
3591  return addCase;
3592 }
3593 
3594 CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) {
3595  // CaseStmts are essentially labels, so they are the first statement in a
3596  // block.
3597  CFGBlock *TopBlock = nullptr, *LastBlock = nullptr;
3598 
3599  if (Stmt *Sub = CS->getSubStmt()) {
3600  // For deeply nested chains of CaseStmts, instead of doing a recursion
3601  // (which can blow out the stack), manually unroll and create blocks
3602  // along the way.
3603  while (isa<CaseStmt>(Sub)) {
3604  CFGBlock *currentBlock = createBlock(false);
3605  currentBlock->setLabel(CS);
3606 
3607  if (TopBlock)
3608  addSuccessor(LastBlock, currentBlock);
3609  else
3610  TopBlock = currentBlock;
3611 
3612  addSuccessor(SwitchTerminatedBlock,
3613  shouldAddCase(switchExclusivelyCovered, switchCond,
3614  CS, *Context)
3615  ? currentBlock : nullptr);
3616 
3617  LastBlock = currentBlock;
3618  CS = cast<CaseStmt>(Sub);
3619  Sub = CS->getSubStmt();
3620  }
3621 
3622  addStmt(Sub);
3623  }
3624 
3625  CFGBlock *CaseBlock = Block;
3626  if (!CaseBlock)
3627  CaseBlock = createBlock();
3628 
3629  // Cases statements partition blocks, so this is the top of the basic block we
3630  // were processing (the "case XXX:" is the label).
3631  CaseBlock->setLabel(CS);
3632 
3633  if (badCFG)
3634  return nullptr;
3635 
3636  // Add this block to the list of successors for the block with the switch
3637  // statement.
3638  assert(SwitchTerminatedBlock);
3639  addSuccessor(SwitchTerminatedBlock, CaseBlock,
3640  shouldAddCase(switchExclusivelyCovered, switchCond,
3641  CS, *Context));
3642 
3643  // We set Block to NULL to allow lazy creation of a new block (if necessary)
3644  Block = nullptr;
3645 
3646  if (TopBlock) {
3647  addSuccessor(LastBlock, CaseBlock);
3648  Succ = TopBlock;
3649  } else {
3650  // This block is now the implicit successor of other blocks.
3651  Succ = CaseBlock;
3652  }
3653 
3654  return Succ;
3655 }
3656 
3657 CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) {
3658  if (Terminator->getSubStmt())
3659  addStmt(Terminator->getSubStmt());
3660 
3661  DefaultCaseBlock = Block;
3662 
3663  if (!DefaultCaseBlock)
3664  DefaultCaseBlock = createBlock();
3665 
3666  // Default statements partition blocks, so this is the top of the basic block
3667  // we were processing (the "default:" is the label).
3668  DefaultCaseBlock->setLabel(Terminator);
3669 
3670  if (badCFG)
3671  return nullptr;
3672 
3673  // Unlike case statements, we don't add the default block to the successors
3674  // for the switch statement immediately. This is done when we finish
3675  // processing the switch statement. This allows for the default case
3676  // (including a fall-through to the code after the switch statement) to always
3677  // be the last successor of a switch-terminated block.
3678 
3679  // We set Block to NULL to allow lazy creation of a new block (if necessary)
3680  Block = nullptr;
3681 
3682  // This block is now the implicit successor of other blocks.
3683  Succ = DefaultCaseBlock;
3684 
3685  return DefaultCaseBlock;
3686 }
3687 
3688 CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) {
3689  // "try"/"catch" is a control-flow statement. Thus we stop processing the
3690  // current block.
3691  CFGBlock *TrySuccessor = nullptr;
3692 
3693  if (Block) {
3694  if (badCFG)
3695  return nullptr;
3696  TrySuccessor = Block;
3697  } else TrySuccessor = Succ;
3698 
3699  CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock;
3700 
3701  // Create a new block that will contain the try statement.
3702  CFGBlock *NewTryTerminatedBlock = createBlock(false);
3703  // Add the terminator in the try block.
3704  NewTryTerminatedBlock->setTerminator(Terminator);
3705 
3706  bool HasCatchAll = false;
3707  for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) {
3708  // The code after the try is the implicit successor.
3709  Succ = TrySuccessor;
3710  CXXCatchStmt *CS = Terminator->getHandler(h);
3711  if (CS->getExceptionDecl() == nullptr) {
3712  HasCatchAll = true;
3713  }
3714  Block = nullptr;
3715  CFGBlock *CatchBlock = VisitCXXCatchStmt(CS);
3716  if (!CatchBlock)
3717  return nullptr;
3718  // Add this block to the list of successors for the block with the try
3719  // statement.
3720  addSuccessor(NewTryTerminatedBlock, CatchBlock);
3721  }
3722  if (!HasCatchAll) {
3723  if (PrevTryTerminatedBlock)
3724  addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock);
3725  else
3726  addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
3727  }
3728 
3729  // The code after the try is the implicit successor.
3730  Succ = TrySuccessor;
3731 
3732  // Save the current "try" context.
3733  SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock);
3734  cfg->addTryDispatchBlock(TryTerminatedBlock);
3735 
3736  assert(Terminator->getTryBlock() && "try must contain a non-NULL body");
3737  Block = nullptr;
3738  return addStmt(Terminator->getTryBlock());
3739 }
3740 
3741 CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) {
3742  // CXXCatchStmt are treated like labels, so they are the first statement in a
3743  // block.
3744 
3745  // Save local scope position because in case of exception variable ScopePos
3746  // won't be restored when traversing AST.
3747  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3748 
3749  // Create local scope for possible exception variable.
3750  // Store scope position. Add implicit destructor.
3751  if (VarDecl *VD = CS->getExceptionDecl()) {
3752  LocalScope::const_iterator BeginScopePos = ScopePos;
3753  addLocalScopeForVarDecl(VD);
3754  addAutomaticObjHandling(ScopePos, BeginScopePos, CS);
3755  }
3756 
3757  if (CS->getHandlerBlock())
3758  addStmt(CS->getHandlerBlock());
3759 
3760  CFGBlock *CatchBlock = Block;
3761  if (!CatchBlock)
3762  CatchBlock = createBlock();
3763 
3764  // CXXCatchStmt is more than just a label. They have semantic meaning
3765  // as well, as they implicitly "initialize" the catch variable. Add
3766  // it to the CFG as a CFGElement so that the control-flow of these
3767  // semantics gets captured.
3768  appendStmt(CatchBlock, CS);
3769 
3770  // Also add the CXXCatchStmt as a label, to mirror handling of regular
3771  // labels.
3772  CatchBlock->setLabel(CS);
3773 
3774  // Bail out if the CFG is bad.
3775  if (badCFG)
3776  return nullptr;
3777 
3778  // We set Block to NULL to allow lazy creation of a new block (if necessary)
3779  Block = nullptr;
3780 
3781  return CatchBlock;
3782 }
3783 
3784 CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) {
3785  // C++0x for-range statements are specified as [stmt.ranged]:
3786  //
3787  // {
3788  // auto && __range = range-init;
3789  // for ( auto __begin = begin-expr,
3790  // __end = end-expr;
3791  // __begin != __end;
3792  // ++__begin ) {
3793  // for-range-declaration = *__begin;
3794  // statement
3795  // }
3796  // }
3797 
3798  // Save local scope position before the addition of the implicit variables.
3799  SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3800 
3801  // Create local scopes and destructors for range, begin and end variables.
3802  if (Stmt *Range = S->getRangeStmt())
3803  addLocalScopeForStmt(Range);
3804  if (Stmt *Begin = S->getBeginStmt())
3805  addLocalScopeForStmt(Begin);
3806  if (Stmt *End = S->getEndStmt())
3807  addLocalScopeForStmt(End);
3808  addAutomaticObjHandling(ScopePos, save_scope_pos.get(), S);
3809 
3810  LocalScope::const_iterator ContinueScopePos = ScopePos;
3811 
3812  // "for" is a control-flow statement. Thus we stop processing the current
3813  // block.
3814  CFGBlock *LoopSuccessor = nullptr;
3815  if (Block) {
3816  if (badCFG)
3817  return nullptr;
3818  LoopSuccessor = Block;
3819  } else
3820  LoopSuccessor = Succ;
3821 
3822  // Save the current value for the break targets.
3823  // All breaks should go to the code following the loop.
3824  SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3825  BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3826 
3827  // The block for the __begin != __end expression.
3828  CFGBlock *ConditionBlock = createBlock(false);
3829  ConditionBlock->setTerminator(S);
3830 
3831  // Now add the actual condition to the condition block.
3832  if (Expr *C = S->getCond()) {
3833  Block = ConditionBlock;
3834  CFGBlock *BeginConditionBlock = addStmt(C);
3835  if (badCFG)
3836  return nullptr;
3837  assert(BeginConditionBlock == ConditionBlock &&
3838  "condition block in for-range was unexpectedly complex");
3839  (void)BeginConditionBlock;
3840  }
3841 
3842  // The condition block is the implicit successor for the loop body as well as
3843  // any code above the loop.
3844  Succ = ConditionBlock;
3845 
3846  // See if this is a known constant.
3847  TryResult KnownVal(true);
3848 
3849  if (S->getCond())
3850  KnownVal = tryEvaluateBool(S->getCond());
3851 
3852  // Now create the loop body.
3853  {
3854  assert(S->getBody());
3855 
3856  // Save the current values for Block, Succ, and continue targets.
3857  SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3858  SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
3859 
3860  // Generate increment code in its own basic block. This is the target of
3861  // continue statements.
3862  Block = nullptr;
3863  Succ = addStmt(S->getInc());
3864  if (badCFG)
3865  return nullptr;
3866  ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
3867 
3868  // The starting block for the loop increment is the block that should
3869  // represent the 'loop target' for looping back to the start of the loop.
3870  ContinueJumpTarget.block->setLoopTarget(S);
3871 
3872  // Finish up the increment block and prepare to start the loop body.
3873  assert(Block);
3874  if (badCFG)
3875  return nullptr;
3876  Block = nullptr;
3877 
3878  // Add implicit scope and dtors for loop variable.
3879  addLocalScopeAndDtors(S->getLoopVarStmt());
3880 
3881  // Populate a new block to contain the loop body and loop variable.
3882  addStmt(S->getBody());
3883  if (badCFG)
3884  return nullptr;
3885  CFGBlock *LoopVarStmtBlock = addStmt(S->getLoopVarStmt());
3886  if (badCFG)
3887  return nullptr;
3888 
3889  // This new body block is a successor to our condition block.
3890  addSuccessor(ConditionBlock,
3891  KnownVal.isFalse() ? nullptr : LoopVarStmtBlock);
3892  }
3893 
3894  // Link up the condition block with the code that follows the loop (the
3895  // false branch).
3896  addSuccessor(ConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
3897 
3898  // Add the initialization statements.
3899  Block = createBlock();
3900  addStmt(S->getBeginStmt());
3901  addStmt(S->getEndStmt());
3902  return addStmt(S->getRangeStmt());
3903 }
3904 
3905 CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E,
3906  AddStmtChoice asc) {
3907  if (BuildOpts.AddTemporaryDtors) {
3908  // If adding implicit destructors visit the full expression for adding
3909  // destructors of temporaries.
3910  TempDtorContext Context;
3911  VisitForTemporaryDtors(E->getSubExpr(), false, Context);
3912 
3913  // Full expression has to be added as CFGStmt so it will be sequenced
3914  // before destructors of it's temporaries.
3915  asc = asc.withAlwaysAdd(true);
3916  }
3917  return Visit(E->getSubExpr(), asc);
3918 }
3919 
3920 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
3921  AddStmtChoice asc) {
3922  if (asc.alwaysAdd(*this, E)) {
3923  autoCreateBlock();
3924  appendStmt(Block, E);
3925 
3926  EnterConstructionContextIfNecessary(E, E->getSubExpr());
3927 
3928  // We do not want to propagate the AlwaysAdd property.
3929  asc = asc.withAlwaysAdd(false);
3930  }
3931  return Visit(E->getSubExpr(), asc);
3932 }
3933 
3934 CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C,
3935  AddStmtChoice asc) {
3936  autoCreateBlock();
3937  appendConstructor(Block, C);
3938 
3939  return VisitChildren(C);
3940 }
3941 
3942 CFGBlock *CFGBuilder::VisitCXXNewExpr(CXXNewExpr *NE,
3943  AddStmtChoice asc) {
3944  autoCreateBlock();
3945  appendStmt(Block, NE);
3946 
3947  EnterConstructionContextIfNecessary(
3948  NE, const_cast<CXXConstructExpr *>(NE->getConstructExpr()));
3949 
3950  if (NE->getInitializer())
3951  Block = Visit(NE->getInitializer());
3952 
3953  if (BuildOpts.AddCXXNewAllocator)
3954  appendNewAllocator(Block, NE);
3955 
3956  if (NE->isArray())
3957  Block = Visit(NE->getArraySize());
3958 
3960  E = NE->placement_arg_end(); I != E; ++I)
3961  Block = Visit(*I);
3962 
3963  return Block;
3964 }
3965 
3966 CFGBlock *CFGBuilder::VisitCXXDeleteExpr(CXXDeleteExpr *DE,
3967  AddStmtChoice asc) {
3968  autoCreateBlock();
3969  appendStmt(Block, DE);
3970  QualType DTy = DE->getDestroyedType();
3971  if (!DTy.isNull()) {
3972  DTy = DTy.getNonReferenceType();
3973  CXXRecordDecl *RD = Context->getBaseElementType(DTy)->getAsCXXRecordDecl();
3974  if (RD) {
3975  if (RD->isCompleteDefinition() && !RD->hasTrivialDestructor())
3976  appendDeleteDtor(Block, RD, DE);
3977  }
3978  }
3979 
3980  return VisitChildren(DE);
3981 }
3982 
3983 CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
3984  AddStmtChoice asc) {
3985  if (asc.alwaysAdd(*this, E)) {
3986  autoCreateBlock();
3987  appendStmt(Block, E);
3988  // We do not want to propagate the AlwaysAdd property.
3989  asc = asc.withAlwaysAdd(false);
3990  }
3991  return Visit(E->getSubExpr(), asc);
3992 }
3993 
3994 CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
3995  AddStmtChoice asc) {
3996  autoCreateBlock();
3997  appendConstructor(Block, C);
3998  return VisitChildren(C);
3999 }
4000 
4001 CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E,
4002  AddStmtChoice asc) {
4003  if (asc.alwaysAdd(*this, E)) {
4004  autoCreateBlock();
4005  appendStmt(Block, E);
4006  }
4007  return Visit(E->getSubExpr(), AddStmtChoice());
4008 }
4009 
4010 CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) {
4011  // Lazily create the indirect-goto dispatch block if there isn't one already.
4012  CFGBlock *IBlock = cfg->getIndirectGotoBlock();
4013 
4014  if (!IBlock) {
4015  IBlock = createBlock(false);
4016  cfg->setIndirectGotoBlock(IBlock);
4017  }
4018 
4019  // IndirectGoto is a control-flow statement. Thus we stop processing the
4020  // current block and create a new one.
4021  if (badCFG)
4022  return nullptr;
4023 
4024  Block = createBlock(false);
4025  Block->setTerminator(I);
4026  addSuccessor(Block, IBlock);
4027  return addStmt(I->getTarget());
4028 }
4029 
4030 CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary,
4031  TempDtorContext &Context) {
4032  assert(BuildOpts.AddImplicitDtors && BuildOpts.AddTemporaryDtors);
4033 
4034 tryAgain:
4035  if (!E) {
4036  badCFG = true;
4037  return nullptr;
4038  }
4039  switch (E->getStmtClass()) {
4040  default:
4041  return VisitChildrenForTemporaryDtors(E, Context);
4042 
4043  case Stmt::BinaryOperatorClass:
4044  return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E),
4045  Context);
4046 
4047  case Stmt::CXXBindTemporaryExprClass:
4048  return VisitCXXBindTemporaryExprForTemporaryDtors(
4049  cast<CXXBindTemporaryExpr>(E), BindToTemporary, Context);
4050 
4051  case Stmt::BinaryConditionalOperatorClass:
4052  case Stmt::ConditionalOperatorClass:
4053  return VisitConditionalOperatorForTemporaryDtors(
4054  cast<AbstractConditionalOperator>(E), BindToTemporary, Context);
4055 
4056  case Stmt::ImplicitCastExprClass:
4057  // For implicit cast we want BindToTemporary to be passed further.
4058  E = cast<CastExpr>(E)->getSubExpr();
4059  goto tryAgain;
4060 
4061  case Stmt::CXXFunctionalCastExprClass:
4062  // For functional cast we want BindToTemporary to be passed further.
4063  E = cast<CXXFunctionalCastExpr>(E)->getSubExpr();
4064  goto tryAgain;
4065 
4066  case Stmt::ParenExprClass:
4067  E = cast<ParenExpr>(E)->getSubExpr();
4068  goto tryAgain;
4069 
4070  case Stmt::MaterializeTemporaryExprClass: {
4071  const MaterializeTemporaryExpr* MTE = cast<MaterializeTemporaryExpr>(E);
4072  BindToTemporary = (MTE->getStorageDuration() != SD_FullExpression);
4073  SmallVector<const Expr *, 2> CommaLHSs;
4075  // Find the expression whose lifetime needs to be extended.
4076  E = const_cast<Expr *>(
4077  cast<MaterializeTemporaryExpr>(E)
4078  ->GetTemporaryExpr()
4079  ->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments));
4080  // Visit the skipped comma operator left-hand sides for other temporaries.
4081  for (const Expr *CommaLHS : CommaLHSs) {
4082  VisitForTemporaryDtors(const_cast<Expr *>(CommaLHS),
4083  /*BindToTemporary=*/false, Context);
4084  }
4085  goto tryAgain;
4086  }
4087 
4088  case Stmt::BlockExprClass:
4089  // Don't recurse into blocks; their subexpressions don't get evaluated
4090  // here.
4091  return Block;
4092 
4093  case Stmt::LambdaExprClass: {
4094  // For lambda expressions, only recurse into the capture initializers,
4095  // and not the body.
4096  auto *LE = cast<LambdaExpr>(E);
4097  CFGBlock *B = Block;
4098  for (Expr *Init : LE->capture_inits()) {
4099  if (CFGBlock *R = VisitForTemporaryDtors(
4100  Init, /*BindToTemporary=*/false, Context))
4101  B = R;
4102  }
4103  return B;
4104  }
4105 
4106  case Stmt::CXXDefaultArgExprClass:
4107  E = cast<CXXDefaultArgExpr>(E)->getExpr();
4108  goto tryAgain;
4109 
4110  case Stmt::CXXDefaultInitExprClass:
4111  E = cast<CXXDefaultInitExpr>(E)->getExpr();
4112  goto tryAgain;
4113  }
4114 }
4115 
4116 CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E,
4117  TempDtorContext &Context) {
4118  if (isa<LambdaExpr>(E)) {
4119  // Do not visit the children of lambdas; they have their own CFGs.
4120  return Block;
4121  }
4122 
4123  // When visiting children for destructors we want to visit them in reverse
4124  // order that they will appear in the CFG. Because the CFG is built
4125  // bottom-up, this means we visit them in their natural order, which
4126  // reverses them in the CFG.
4127  CFGBlock *B = Block;
4128  for (Stmt *Child : E->children())
4129  if (Child)
4130  if (CFGBlock *R = VisitForTemporaryDtors(Child, false, Context))
4131  B = R;
4132 
4133  return B;
4134 }
4135 
4136 CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(
4137  BinaryOperator *E, TempDtorContext &Context) {
4138  if (E->isLogicalOp()) {
4139  VisitForTemporaryDtors(E->getLHS(), false, Context);
4140  TryResult RHSExecuted = tryEvaluateBool(E->getLHS());
4141  if (RHSExecuted.isKnown() && E->getOpcode() == BO_LOr)
4142  RHSExecuted.negate();
4143 
4144  // We do not know at CFG-construction time whether the right-hand-side was
4145  // executed, thus we add a branch node that depends on the temporary
4146  // constructor call.
4147  TempDtorContext RHSContext(
4148  bothKnownTrue(Context.KnownExecuted, RHSExecuted));
4149  VisitForTemporaryDtors(E->getRHS(), false, RHSContext);
4150  InsertTempDtorDecisionBlock(RHSContext);
4151 
4152  return Block;
4153  }
4154 
4155  if (E->isAssignmentOp()) {
4156  // For assignment operator (=) LHS expression is visited
4157  // before RHS expression. For destructors visit them in reverse order.
4158  CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
4159  CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
4160  return LHSBlock ? LHSBlock : RHSBlock;
4161  }
4162 
4163  // For any other binary operator RHS expression is visited before
4164  // LHS expression (order of children). For destructors visit them in reverse
4165  // order.
4166  CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
4167  CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
4168  return RHSBlock ? RHSBlock : LHSBlock;
4169 }
4170 
4171 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors(
4172  CXXBindTemporaryExpr *E, bool BindToTemporary, TempDtorContext &Context) {
4173  // First add destructors for temporaries in subexpression.
4174  CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr(), false, Context);
4175  if (!BindToTemporary) {
4176  // If lifetime of temporary is not prolonged (by assigning to constant
4177  // reference) add destructor for it.
4178 
4179  const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor();
4180 
4181  if (Dtor->getParent()->isAnyDestructorNoReturn()) {
4182  // If the destructor is marked as a no-return destructor, we need to
4183  // create a new block for the destructor which does not have as a
4184  // successor anything built thus far. Control won't flow out of this
4185  // block.
4186  if (B) Succ = B;
4187  Block = createNoReturnBlock();
4188  } else if (Context.needsTempDtorBranch()) {
4189  // If we need to introduce a branch, we add a new block that we will hook
4190  // up to a decision block later.
4191  if (B) Succ = B;
4192  Block = createBlock();
4193  } else {
4194  autoCreateBlock();
4195  }
4196  if (Context.needsTempDtorBranch()) {
4197  Context.setDecisionPoint(Succ, E);
4198  }
4199  appendTemporaryDtor(Block, E);
4200 
4201  B = Block;
4202  }
4203  return B;
4204 }
4205 
4206 void CFGBuilder::InsertTempDtorDecisionBlock(const TempDtorContext &Context,
4207  CFGBlock *FalseSucc) {
4208  if (!Context.TerminatorExpr) {
4209  // If no temporary was found, we do not need to insert a decision point.
4210  return;
4211  }
4212  assert(Context.TerminatorExpr);
4213  CFGBlock *Decision = createBlock(false);
4214  Decision->setTerminator(CFGTerminator(Context.TerminatorExpr, true));
4215  addSuccessor(Decision, Block, !Context.KnownExecuted.isFalse());
4216  addSuccessor(Decision, FalseSucc ? FalseSucc : Context.Succ,
4217  !Context.KnownExecuted.isTrue());
4218  Block = Decision;
4219 }
4220 
4221 CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors(
4222  AbstractConditionalOperator *E, bool BindToTemporary,
4223  TempDtorContext &Context) {
4224  VisitForTemporaryDtors(E->getCond(), false, Context);
4225  CFGBlock *ConditionBlock = Block;
4226  CFGBlock *ConditionSucc = Succ;
4227  TryResult ConditionVal = tryEvaluateBool(E->getCond());
4228  TryResult NegatedVal = ConditionVal;
4229  if (NegatedVal.isKnown()) NegatedVal.negate();
4230 
4231  TempDtorContext TrueContext(
4232  bothKnownTrue(Context.KnownExecuted, ConditionVal));
4233  VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary, TrueContext);
4234  CFGBlock *TrueBlock = Block;
4235 
4236  Block = ConditionBlock;
4237  Succ = ConditionSucc;
4238  TempDtorContext FalseContext(
4239  bothKnownTrue(Context.KnownExecuted, NegatedVal));
4240  VisitForTemporaryDtors(E->getFalseExpr(), BindToTemporary, FalseContext);
4241 
4242  if (TrueContext.TerminatorExpr && FalseContext.TerminatorExpr) {
4243  InsertTempDtorDecisionBlock(FalseContext, TrueBlock);
4244  } else if (TrueContext.TerminatorExpr) {
4245  Block = TrueBlock;
4246  InsertTempDtorDecisionBlock(TrueContext);
4247  } else {
4248  InsertTempDtorDecisionBlock(FalseContext);
4249  }
4250  return Block;
4251 }
4252 
4253 /// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has
4254 /// no successors or predecessors. If this is the first block created in the
4255 /// CFG, it is automatically set to be the Entry and Exit of the CFG.
4257  bool first_block = begin() == end();
4258 
4259  // Create the block.
4260  CFGBlock *Mem = getAllocator().Allocate<CFGBlock>();
4261  new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this);
4262  Blocks.push_back(Mem, BlkBVC);
4263 
4264  // If this is the first block, set it as the Entry and Exit.
4265  if (first_block)
4266  Entry = Exit = &back();
4267 
4268  // Return the block.
4269  return &back();
4270 }
4271 
4272 /// buildCFG - Constructs a CFG from an AST.
4273 std::unique_ptr<CFG> CFG::buildCFG(const Decl *D, Stmt *Statement,
4274  ASTContext *C, const BuildOptions &BO) {
4275  CFGBuilder Builder(C, BO);
4276  return Builder.buildCFG(D, Statement);
4277 }
4278 
4279 const CXXDestructorDecl *
4281  switch (getKind()) {
4284  case CFGElement::LoopExit:
4286  case CFGElement::Statement:
4288  llvm_unreachable("getDestructorDecl should only be used with "
4289  "ImplicitDtors");
4291  const VarDecl *var = castAs<CFGAutomaticObjDtor>().getVarDecl();
4292  QualType ty = var->getType();
4293 
4294  // FIXME: See CFGBuilder::addLocalScopeForVarDecl.
4295  //
4296  // Lifetime-extending constructs are handled here. This works for a single
4297  // temporary in an initializer expression.
4298  if (ty->isReferenceType()) {
4299  if (const Expr *Init = var->getInit()) {
4300  ty = getReferenceInitTemporaryType(astContext, Init);
4301  }
4302  }
4303 
4304  while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) {
4305  ty = arrayType->getElementType();
4306  }
4307  const RecordType *recordType = ty->getAs<RecordType>();
4308  const CXXRecordDecl *classDecl =
4309  cast<CXXRecordDecl>(recordType->getDecl());
4310  return classDecl->getDestructor();
4311  }
4312  case CFGElement::DeleteDtor: {
4313  const CXXDeleteExpr *DE = castAs<CFGDeleteDtor>().getDeleteExpr();
4314  QualType DTy = DE->getDestroyedType();
4315  DTy = DTy.getNonReferenceType();
4316  const CXXRecordDecl *classDecl =
4317  astContext.getBaseElementType(DTy)->getAsCXXRecordDecl();
4318  return classDecl->getDestructor();
4319  }
4321  const CXXBindTemporaryExpr *bindExpr =
4322  castAs<CFGTemporaryDtor>().getBindTemporaryExpr();
4323  const CXXTemporary *temp = bindExpr->getTemporary();
4324  return temp->getDestructor();
4325  }
4326  case CFGElement::BaseDtor:
4328  // Not yet supported.
4329  return nullptr;
4330  }
4331  llvm_unreachable("getKind() returned bogus value");
4332 }
4333 
4334 bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const {
4335  if (const CXXDestructorDecl *DD = getDestructorDecl(astContext))
4336  return DD->isNoReturn();
4337  return false;
4338 }
4339 
4340 //===----------------------------------------------------------------------===//
4341 // CFGBlock operations.
4342 //===----------------------------------------------------------------------===//
4343 
4345  : ReachableBlock(IsReachable ? B : nullptr),
4346  UnreachableBlock(!IsReachable ? B : nullptr,
4347  B && IsReachable ? AB_Normal : AB_Unreachable) {}
4348 
4350  : ReachableBlock(B),
4351  UnreachableBlock(B == AlternateBlock ? nullptr : AlternateBlock,
4352  B == AlternateBlock ? AB_Alternate : AB_Normal) {}
4353 
4355  BumpVectorContext &C) {
4356  if (CFGBlock *B = Succ.getReachableBlock())
4357  B->Preds.push_back(AdjacentBlock(this, Succ.isReachable()), C);
4358 
4359  if (CFGBlock *UnreachableB = Succ.getPossiblyUnreachableBlock())
4360  UnreachableB->Preds.push_back(AdjacentBlock(this, false), C);
4361 
4362  Succs.push_back(Succ, C);
4363 }
4364 
4366  const CFGBlock *From, const CFGBlock *To) {
4367  if (F.IgnoreNullPredecessors && !From)
4368  return true;
4369 
4370  if (To && From && F.IgnoreDefaultsWithCoveredEnums) {
4371  // If the 'To' has no label or is labeled but the label isn't a
4372  // CaseStmt then filter this edge.
4373  if (const SwitchStmt *S =
4374  dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) {
4375  if (S->isAllEnumCasesCovered()) {
4376  const Stmt *L = To->getLabel();
4377  if (!L || !isa<CaseStmt>(L))
4378  return true;
4379  }
4380  }
4381  }
4382 
4383  return false;
4384 }
4385 
4386 //===----------------------------------------------------------------------===//
4387 // CFG pretty printing
4388 //===----------------------------------------------------------------------===//
4389 
4390 namespace {
4391 
4392 class StmtPrinterHelper : public PrinterHelper {
4393  using StmtMapTy = llvm::DenseMap<const Stmt *, std::pair<unsigned, unsigned>>;
4394  using DeclMapTy = llvm::DenseMap<const Decl *, std::pair<unsigned, unsigned>>;
4395 
4396  StmtMapTy StmtMap;
4397  DeclMapTy DeclMap;
4398  signed currentBlock = 0;
4399  unsigned currStmt = 0;
4400  const LangOptions &LangOpts;
4401 
4402 public:
4403  StmtPrinterHelper(const CFG* cfg, const LangOptions &LO)
4404  : LangOpts(LO) {
4405  for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) {
4406  unsigned j = 1;
4407  for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ;
4408  BI != BEnd; ++BI, ++j ) {
4409  if (Optional<CFGStmt> SE = BI->getAs<CFGStmt>()) {
4410  const Stmt *stmt= SE->getStmt();
4411  std::pair<unsigned, unsigned> P((*I)->getBlockID(), j);
4412  StmtMap[stmt] = P;
4413 
4414  switch (stmt->getStmtClass()) {
4415  case Stmt::DeclStmtClass:
4416  DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P;
4417  break;
4418  case Stmt::IfStmtClass: {
4419  const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable();
4420  if (var)
4421  DeclMap[var] = P;
4422  break;
4423  }
4424  case Stmt::ForStmtClass: {
4425  const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable();
4426  if (var)
4427  DeclMap[var] = P;
4428  break;
4429  }
4430  case Stmt::WhileStmtClass: {
4431  const VarDecl *var =
4432  cast<WhileStmt>(stmt)->getConditionVariable();
4433  if (var)
4434  DeclMap[var] = P;
4435  break;
4436  }
4437  case Stmt::SwitchStmtClass: {
4438  const VarDecl *var =
4439  cast<SwitchStmt>(stmt)->getConditionVariable();
4440  if (var)
4441  DeclMap[var] = P;
4442  break;
4443  }
4444  case Stmt::CXXCatchStmtClass: {
4445  const VarDecl *var =
4446  cast<CXXCatchStmt>(stmt)->getExceptionDecl();
4447  if (var)
4448  DeclMap[var] = P;
4449  break;
4450  }
4451  default:
4452  break;
4453  }
4454  }
4455  }
4456  }
4457  }
4458 
4459  ~StmtPrinterHelper() override = default;
4460 
4461  const LangOptions &getLangOpts() const { return LangOpts; }
4462  void setBlockID(signed i) { currentBlock = i; }
4463  void setStmtID(unsigned i) { currStmt = i; }
4464 
4465  bool handledStmt(Stmt *S, raw_ostream &OS) override {
4466  StmtMapTy::iterator I = StmtMap.find(S);
4467 
4468  if (I == StmtMap.end())
4469  return false;
4470 
4471  if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
4472  && I->second.second == currStmt) {
4473  return false;
4474  }
4475 
4476  OS << "[B" << I->second.first << "." << I->second.second << "]";
4477  return true;
4478  }
4479 
4480  bool handleDecl(const Decl *D, raw_ostream &OS) {
4481  DeclMapTy::iterator I = DeclMap.find(D);
4482 
4483  if (I == DeclMap.end())
4484  return false;
4485 
4486  if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
4487  && I->second.second == currStmt) {
4488  return false;
4489  }
4490 
4491  OS << "[B" << I->second.first << "." << I->second.second << "]";
4492  return true;
4493  }
4494 };
4495 
4496 class CFGBlockTerminatorPrint
4497  : public StmtVisitor<CFGBlockTerminatorPrint,void> {
4498  raw_ostream &OS;
4499  StmtPrinterHelper* Helper;
4500  PrintingPolicy Policy;
4501 
4502 public:
4503  CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper,
4504  const PrintingPolicy &Policy)
4505  : OS(os), Helper(helper), Policy(Policy) {
4506  this->Policy.IncludeNewlines = false;
4507  }
4508 
4509  void VisitIfStmt(IfStmt *I) {
4510  OS << "if ";
4511  if (Stmt *C = I->getCond())
4512  C->printPretty(OS, Helper, Policy);
4513  }
4514 
4515  // Default case.
4516  void VisitStmt(Stmt *Terminator) {
4517  Terminator->printPretty(OS, Helper, Policy);
4518  }
4519 
4520  void VisitDeclStmt(DeclStmt *DS) {
4521  VarDecl *VD = cast<VarDecl>(DS->getSingleDecl());
4522  OS << "static init " << VD->getName();
4523  }
4524 
4525  void VisitForStmt(ForStmt *F) {
4526  OS << "for (" ;
4527  if (F->getInit())
4528  OS << "...";
4529  OS << "; ";
4530  if (Stmt *C = F->getCond())
4531  C->printPretty(OS, Helper, Policy);
4532  OS << "; ";
4533  if (F->getInc())
4534  OS << "...";
4535  OS << ")";
4536  }
4537 
4538  void VisitWhileStmt(WhileStmt *W) {
4539  OS << "while " ;
4540  if (Stmt *C = W->getCond())
4541  C->printPretty(OS, Helper, Policy);
4542  }
4543 
4544  void VisitDoStmt(DoStmt *D) {
4545  OS << "do ... while ";
4546  if (Stmt *C = D->getCond())
4547  C->printPretty(OS, Helper, Policy);
4548  }
4549 
4550  void VisitSwitchStmt(SwitchStmt *Terminator) {
4551  OS << "switch ";
4552  Terminator->getCond()->printPretty(OS, Helper, Policy);
4553  }
4554 
4555  void VisitCXXTryStmt(CXXTryStmt *CS) {
4556  OS << "try ...";
4557  }
4558 
4559  void VisitSEHTryStmt(SEHTryStmt *CS) {
4560  OS << "__try ...";
4561  }
4562 
4563  void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) {
4564  if (Stmt *Cond = C->getCond())
4565  Cond->printPretty(OS, Helper, Policy);
4566  OS << " ? ... : ...";
4567  }
4568 
4569  void VisitChooseExpr(ChooseExpr *C) {
4570  OS << "__builtin_choose_expr( ";
4571  if (Stmt *Cond = C->getCond())
4572  Cond->printPretty(OS, Helper, Policy);
4573  OS << " )";
4574  }
4575 
4576  void VisitIndirectGotoStmt(IndirectGotoStmt *I) {
4577  OS << "goto *";
4578  if (Stmt *T = I->getTarget())
4579  T->printPretty(OS, Helper, Policy);
4580  }
4581 
4582  void VisitBinaryOperator(BinaryOperator* B) {
4583  if (!B->isLogicalOp()) {
4584  VisitExpr(B);
4585  return;
4586  }
4587 
4588  if (B->getLHS())
4589  B->getLHS()->printPretty(OS, Helper, Policy);
4590 
4591  switch (B->getOpcode()) {
4592  case BO_LOr:
4593  OS << " || ...";
4594  return;
4595  case BO_LAnd:
4596  OS << " && ...";
4597  return;
4598  default:
4599  llvm_unreachable("Invalid logical operator.");
4600  }
4601  }
4602 
4603  void VisitExpr(Expr *E) {
4604  E->printPretty(OS, Helper, Policy);
4605  }
4606 
4607 public:
4608  void print(CFGTerminator T) {
4609  if (T.isTemporaryDtorsBranch())
4610  OS << "(Temp Dtor) ";
4611  Visit(T.getStmt());
4612  }
4613 };
4614 
4615 } // namespace
4616 
4617 static void print_initializer(raw_ostream &OS, StmtPrinterHelper &Helper,
4618  const CXXCtorInitializer *I) {
4619  if (I->isBaseInitializer())
4620  OS << I->getBaseClass()->getAsCXXRecordDecl()->getName();
4621  else if (I->isDelegatingInitializer())
4623  else
4624  OS << I->getAnyMember()->getName();
4625  OS << "(";
4626  if (Expr *IE = I->getInit())
4627  IE->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
4628  OS << ")";
4629 
4630  if (I->isBaseInitializer())
4631  OS << " (Base initializer)";
4632  else if (I->isDelegatingInitializer())
4633  OS << " (Delegating initializer)";
4634  else
4635  OS << " (Member initializer)";
4636 }
4637 
4638 static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
4639  const CFGElement &E) {
4640  if (Optional<CFGStmt> CS = E.getAs<CFGStmt>()) {
4641  const Stmt *S = CS->getStmt();
4642  assert(S != nullptr && "Expecting non-null Stmt");
4643 
4644  // special printing for statement-expressions.
4645  if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) {
4646  const CompoundStmt *Sub = SE->getSubStmt();
4647 
4648  auto Children = Sub->children();
4649  if (Children.begin() != Children.end()) {
4650  OS << "({ ... ; ";
4651  Helper.handledStmt(*SE->getSubStmt()->body_rbegin(),OS);
4652  OS << " })\n";
4653  return;
4654  }
4655  }
4656  // special printing for comma expressions.
4657  if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) {
4658  if (B->getOpcode() == BO_Comma) {
4659  OS << "... , ";
4660  Helper.handledStmt(B->getRHS(),OS);
4661  OS << '\n';
4662  return;
4663  }
4664  }
4665  S->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
4666 
4667  if (isa<CXXOperatorCallExpr>(S)) {
4668  OS << " (OperatorCall)";
4669  } else if (isa<CXXBindTemporaryExpr>(S)) {
4670  OS << " (BindTemporary)";
4671  } else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) {
4672  OS << " (CXXConstructExpr, ";
4674  if (const Stmt *S = CE->getTriggerStmt())
4675  Helper.handledStmt((const_cast<Stmt *>(S)), OS);
4676  else if (const CXXCtorInitializer *I = CE->getTriggerInit())
4677  print_initializer(OS, Helper, I);
4678  else
4679  llvm_unreachable("Unexpected trigger kind!");
4680  OS << ", ";
4681  }
4682  OS << CCE->getType().getAsString() << ")";
4683  } else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) {
4684  OS << " (" << CE->getStmtClassName() << ", "
4685  << CE->getCastKindName()
4686  << ", " << CE->getType().getAsString()
4687  << ")";
4688  }
4689 
4690  // Expressions need a newline.
4691  if (isa<Expr>(S))
4692  OS << '\n';
4693  } else if (Optional<CFGInitializer> IE = E.getAs<CFGInitializer>()) {
4694  print_initializer(OS, Helper, IE->getInitializer());
4695  OS << '\n';
4696  } else if (Optional<CFGAutomaticObjDtor> DE =
4697  E.getAs<CFGAutomaticObjDtor>()) {
4698  const VarDecl *VD = DE->getVarDecl();
4699  Helper.handleDecl(VD, OS);
4700 
4701  const Type* T = VD->getType().getTypePtr();
4702  if (const ReferenceType* RT = T->getAs<ReferenceType>())
4703  T = RT->getPointeeType().getTypePtr();
4704  T = T->getBaseElementTypeUnsafe();
4705 
4706  OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()";
4707  OS << " (Implicit destructor)\n";
4708  } else if (Optional<CFGLifetimeEnds> DE = E.getAs<CFGLifetimeEnds>()) {
4709  const VarDecl *VD = DE->getVarDecl();
4710  Helper.handleDecl(VD, OS);
4711 
4712  OS << " (Lifetime ends)\n";
4713  } else if (Optional<CFGLoopExit> LE = E.getAs<CFGLoopExit>()) {
4714  const Stmt *LoopStmt = LE->getLoopStmt();
4715  OS << LoopStmt->getStmtClassName() << " (LoopExit)\n";
4716  } else if (Optional<CFGNewAllocator> NE = E.getAs<CFGNewAllocator>()) {
4717  OS << "CFGNewAllocator(";
4718  if (const CXXNewExpr *AllocExpr = NE->getAllocatorExpr())
4719  AllocExpr->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
4720  OS << ")\n";
4721  } else if (Optional<CFGDeleteDtor> DE = E.getAs<CFGDeleteDtor>()) {
4722  const CXXRecordDecl *RD = DE->getCXXRecordDecl();
4723  if (!RD)
4724  return;
4725  CXXDeleteExpr *DelExpr =
4726  const_cast<CXXDeleteExpr*>(DE->getDeleteExpr());
4727  Helper.handledStmt(cast<Stmt>(DelExpr->getArgument()), OS);
4728  OS << "->~" << RD->getName().str() << "()";
4729  OS << " (Implicit destructor)\n";
4730  } else if (Optional<CFGBaseDtor> BE = E.getAs<CFGBaseDtor>()) {
4731  const CXXBaseSpecifier *BS = BE->getBaseSpecifier();
4732  OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()";
4733  OS << " (Base object destructor)\n";
4734  } else if (Optional<CFGMemberDtor> ME = E.getAs<CFGMemberDtor>()) {
4735  const FieldDecl *FD = ME->getFieldDecl();
4736  const Type *T = FD->getType()->getBaseElementTypeUnsafe();
4737  OS << "this->" << FD->getName();
4738  OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()";
4739  OS << " (Member object destructor)\n";
4740  } else if (Optional<CFGTemporaryDtor> TE = E.getAs<CFGTemporaryDtor>()) {
4741  const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr();
4742  OS << "~";
4743  BT->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
4744  OS << "() (Temporary object destructor)\n";
4745  }
4746 }
4747 
4748 static void print_block(raw_ostream &OS, const CFG* cfg,
4749  const CFGBlock &B,
4750  StmtPrinterHelper &Helper, bool print_edges,
4751  bool ShowColors) {
4752  Helper.setBlockID(B.getBlockID());
4753 
4754  // Print the header.
4755  if (ShowColors)
4756  OS.changeColor(raw_ostream::YELLOW, true);
4757 
4758  OS << "\n [B" << B.getBlockID();
4759 
4760  if (&B == &cfg->getEntry())
4761  OS << " (ENTRY)]\n";
4762  else if (&B == &cfg->getExit())
4763  OS << " (EXIT)]\n";
4764  else if (&B == cfg->getIndirectGotoBlock())
4765  OS << " (INDIRECT GOTO DISPATCH)]\n";
4766  else if (B.hasNoReturnElement())
4767  OS << " (NORETURN)]\n";
4768  else
4769  OS << "]\n";
4770 
4771  if (ShowColors)
4772  OS.resetColor();
4773 
4774  // Print the label of this block.
4775  if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) {
4776  if (print_edges)
4777  OS << " ";
4778 
4779  if (LabelStmt *L = dyn_cast<LabelStmt>(Label))
4780  OS << L->getName();
4781  else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) {
4782  OS << "case ";
4783  if (C->getLHS())
4784  C->getLHS()->printPretty(OS, &Helper,
4785  PrintingPolicy(Helper.getLangOpts()));
4786  if (C->getRHS()) {
4787  OS << " ... ";
4788  C->getRHS()->printPretty(OS, &Helper,
4789  PrintingPolicy(Helper.getLangOpts()));
4790  }
4791  } else if (isa<DefaultStmt>(Label))
4792  OS << "default";
4793  else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) {
4794  OS << "catch (";
4795  if (CS->getExceptionDecl())
4796  CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper.getLangOpts()),
4797  0);
4798  else
4799  OS << "...";
4800  OS << ")";
4801  } else if (SEHExceptStmt *ES = dyn_cast<SEHExceptStmt>(Label)) {
4802  OS << "__except (";
4803  ES->getFilterExpr()->printPretty(OS, &Helper,
4804  PrintingPolicy(Helper.getLangOpts()), 0);
4805  OS << ")";
4806  } else
4807  llvm_unreachable("Invalid label statement in CFGBlock.");
4808 
4809  OS << ":\n";
4810  }
4811 
4812  // Iterate through the statements in the block and print them.
4813  unsigned j = 1;
4814 
4815  for (CFGBlock::const_iterator I = B.begin(), E = B.end() ;
4816  I != E ; ++I, ++j ) {
4817  // Print the statement # in the basic block and the statement itself.
4818  if (print_edges)
4819  OS << " ";
4820 
4821  OS << llvm::format("%3d", j) << ": ";
4822 
4823  Helper.setStmtID(j);
4824 
4825  print_elem(OS, Helper, *I);
4826  }
4827 
4828  // Print the terminator of this block.
4829  if (B.getTerminator()) {
4830  if (ShowColors)
4831  OS.changeColor(raw_ostream::GREEN);
4832 
4833  OS << " T: ";
4834 
4835  Helper.setBlockID(-1);
4836 
4837  PrintingPolicy PP(Helper.getLangOpts());
4838  CFGBlockTerminatorPrint TPrinter(OS, &Helper, PP);
4839  TPrinter.print(B.getTerminator());
4840  OS << '\n';
4841 
4842  if (ShowColors)
4843  OS.resetColor();
4844  }
4845 
4846  if (print_edges) {
4847  // Print the predecessors of this block.
4848  if (!B.pred_empty()) {
4849  const raw_ostream::Colors Color = raw_ostream::BLUE;
4850  if (ShowColors)
4851  OS.changeColor(Color);
4852  OS << " Preds " ;
4853  if (ShowColors)
4854  OS.resetColor();
4855  OS << '(' << B.pred_size() << "):";
4856  unsigned i = 0;
4857 
4858  if (ShowColors)
4859  OS.changeColor(Color);
4860 
4861  for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end();
4862  I != E; ++I, ++i) {
4863  if (i % 10 == 8)
4864  OS << "\n ";
4865 
4866  CFGBlock *B = *I;
4867  bool Reachable = true;
4868  if (!B) {
4869  Reachable = false;
4870  B = I->getPossiblyUnreachableBlock();
4871  }
4872 
4873  OS << " B" << B->getBlockID();
4874  if (!Reachable)
4875  OS << "(Unreachable)";
4876  }
4877 
4878  if (ShowColors)
4879  OS.resetColor();
4880 
4881  OS << '\n';
4882  }
4883 
4884  // Print the successors of this block.
4885  if (!B.succ_empty()) {
4886  const raw_ostream::Colors Color = raw_ostream::MAGENTA;
4887  if (ShowColors)
4888  OS.changeColor(Color);
4889  OS << " Succs ";
4890  if (ShowColors)
4891  OS.resetColor();
4892  OS << '(' << B.succ_size() << "):";
4893  unsigned i = 0;
4894 
4895  if (ShowColors)
4896  OS.changeColor(Color);
4897 
4898  for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end();
4899  I != E; ++I, ++i) {
4900  if (i % 10 == 8)
4901  OS << "\n ";
4902 
4903  CFGBlock *B = *I;
4904 
4905  bool Reachable = true;
4906  if (!B) {
4907  Reachable = false;
4908  B = I->getPossiblyUnreachableBlock();
4909  }
4910 
4911  if (B) {
4912  OS << " B" << B->getBlockID();
4913  if (!Reachable)
4914  OS << "(Unreachable)";
4915  }
4916  else {
4917  OS << " NULL";
4918  }
4919  }
4920 
4921  if (ShowColors)
4922  OS.resetColor();
4923  OS << '\n';
4924  }
4925  }
4926 }
4927 
4928 /// dump - A simple pretty printer of a CFG that outputs to stderr.
4929 void CFG::dump(const LangOptions &LO, bool ShowColors) const {
4930  print(llvm::errs(), LO, ShowColors);
4931 }
4932 
4933 /// print - A simple pretty printer of a CFG that outputs to an ostream.
4934 void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const {
4935  StmtPrinterHelper Helper(this, LO);
4936 
4937  // Print the entry block.
4938  print_block(OS, this, getEntry(), Helper, true, ShowColors);
4939 
4940  // Iterate through the CFGBlocks and print them one by one.
4941  for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) {
4942  // Skip the entry block, because we already printed it.
4943  if (&(**I) == &getEntry() || &(**I) == &getExit())
4944  continue;
4945 
4946  print_block(OS, this, **I, Helper, true, ShowColors);
4947  }
4948 
4949  // Print the exit block.
4950  print_block(OS, this, getExit(), Helper, true, ShowColors);
4951  OS << '\n';
4952  OS.flush();
4953 }
4954 
4955 /// dump - A simply pretty printer of a CFGBlock that outputs to stderr.
4956 void CFGBlock::dump(const CFG* cfg, const LangOptions &LO,
4957  bool ShowColors) const {
4958  print(llvm::errs(), cfg, LO, ShowColors);
4959 }
4960 
4961 LLVM_DUMP_METHOD void CFGBlock::dump() const {
4962  dump(getParent(), LangOptions(), false);
4963 }
4964 
4965 /// print - A simple pretty printer of a CFGBlock that outputs to an ostream.
4966 /// Generally this will only be called from CFG::print.
4967 void CFGBlock::print(raw_ostream &OS, const CFG* cfg,
4968  const LangOptions &LO, bool ShowColors) const {
4969  StmtPrinterHelper Helper(cfg, LO);
4970  print_block(OS, cfg, *this, Helper, true, ShowColors);
4971  OS << '\n';
4972 }
4973 
4974 /// printTerminator - A simple pretty printer of the terminator of a CFGBlock.
4975 void CFGBlock::printTerminator(raw_ostream &OS,
4976  const LangOptions &LO) const {
4977  CFGBlockTerminatorPrint TPrinter(OS, nullptr, PrintingPolicy(LO));
4978  TPrinter.print(getTerminator());
4979 }
4980 
4982  Stmt *Terminator = this->Terminator;
4983  if (!Terminator)
4984  return nullptr;
4985 
4986  Expr *E = nullptr;
4987 
4988  switch (Terminator->getStmtClass()) {
4989  default:
4990  break;
4991 
4992  case Stmt::CXXForRangeStmtClass:
4993  E = cast<CXXForRangeStmt>(Terminator)->getCond();
4994  break;
4995 
4996  case Stmt::ForStmtClass:
4997  E = cast<ForStmt>(Terminator)->getCond();
4998  break;
4999 
5000  case Stmt::WhileStmtClass:
5001  E = cast<WhileStmt>(Terminator)->getCond();
5002  break;
5003 
5004  case Stmt::DoStmtClass:
5005  E = cast<DoStmt>(Terminator)->getCond();
5006  break;
5007 
5008  case Stmt::IfStmtClass:
5009  E = cast<IfStmt>(Terminator)->getCond();
5010  break;
5011 
5012  case Stmt::ChooseExprClass:
5013  E = cast<ChooseExpr>(Terminator)->getCond();
5014  break;
5015 
5016  case Stmt::IndirectGotoStmtClass:
5017  E = cast<IndirectGotoStmt>(Terminator)->getTarget();
5018  break;
5019 
5020  case Stmt::SwitchStmtClass:
5021  E = cast<SwitchStmt>(Terminator)->getCond();
5022  break;
5023 
5024  case Stmt::BinaryConditionalOperatorClass:
5025  E = cast<BinaryConditionalOperator>(Terminator)->getCond();
5026  break;
5027 
5028  case Stmt::ConditionalOperatorClass:
5029  E = cast<ConditionalOperator>(Terminator)->getCond();
5030  break;
5031 
5032  case Stmt::BinaryOperatorClass: // '&&' and '||'
5033  E = cast<BinaryOperator>(Terminator)->getLHS();
5034  break;
5035 
5036  case Stmt::ObjCForCollectionStmtClass:
5037  return Terminator;
5038  }
5039 
5040  if (!StripParens)
5041  return E;
5042 
5043  return E ? E->IgnoreParens() : nullptr;
5044 }
5045 
5046 //===----------------------------------------------------------------------===//
5047 // CFG Graphviz Visualization
5048 //===----------------------------------------------------------------------===//
5049 
5050 #ifndef NDEBUG
5051 static StmtPrinterHelper* GraphHelper;
5052 #endif
5053 
5054 void CFG::viewCFG(const LangOptions &LO) const {
5055 #ifndef NDEBUG
5056  StmtPrinterHelper H(this, LO);
5057  GraphHelper = &H;
5058  llvm::ViewGraph(this,"CFG");
5059  GraphHelper = nullptr;
5060 #endif
5061 }
5062 
5063 namespace llvm {
5064 
5065 template<>
5066 struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits {
5067  DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
5068 
5069  static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) {
5070 #ifndef NDEBUG
5071  std::string OutSStr;
5072  llvm::raw_string_ostream Out(OutSStr);
5073  print_block(Out,Graph, *Node, *GraphHelper, false, false);
5074  std::string& OutStr = Out.str();
5075 
5076  if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
5077 
5078  // Process string output to make it nicer...
5079  for (unsigned i = 0; i != OutStr.length(); ++i)
5080  if (OutStr[i] == '\n') { // Left justify
5081  OutStr[i] = '\\';
5082  OutStr.insert(OutStr.begin()+i+1, 'l');
5083  }
5084 
5085  return OutStr;
5086 #else
5087  return {};
5088 #endif
5089  }
5090 };
5091 
5092 } // namespace llvm
Expr * getInc()
Definition: Stmt.h:1241
unsigned getNumSemanticExprs() const
Definition: Expr.h:5046
bool isBaseInitializer() const
Determine whether this initializer is initializing a base class.
Definition: DeclCXX.h:2293
bool isNoReturn() const
Determines whether this function is known to be &#39;noreturn&#39;, through an attribute on its declaration o...
Definition: Decl.cpp:2820
Defines the clang::ASTContext interface.
const BlockDecl * getBlockDecl() const
Definition: Expr.h:4878
CFGNewAllocator - Represents C++ allocator call.
Definition: CFG.h:245
const CXXDestructorDecl * getDestructor() const
Definition: ExprCXX.h:1175
Represents a function declaration or definition.
Definition: Decl.h:1696
Expr * getInit() const
Get the initializer.
Definition: DeclCXX.h:2422
const Stmt * getElse() const
Definition: Stmt.h:973
CompoundStmt * getBlock() const
Definition: Stmt.h:1962
bool EvaluateAsRValue(EvalResult &Result, const ASTContext &Ctx) const
EvaluateAsRValue - Return true if this is a constant which we can fold to an rvalue using any crazy t...
A class which contains all the information about a particular captured value.
Definition: Decl.h:3717
pred_iterator pred_end()
Definition: CFG.h:694
PointerType - C99 6.7.5.1 - Pointer Declarators.
Definition: Type.h:2289
QualType getPointeeType() const
Definition: Type.h:2302
A (possibly-)qualified type.
Definition: Type.h:653
bool isBlockPointerType() const
Definition: Type.h:5956
base_class_range bases()
Definition: DeclCXX.h:784
Expr * getCond() const
Definition: Expr.h:3722
static SourceLocation GetEndLoc(Decl *D)
Definition: CFG.cpp:65
AdjacentBlocks::const_iterator const_pred_iterator
Definition: CFG.h:680
const internal::VariadicAllOfMatcher< Stmt > stmt
Matches statements.
void print(raw_ostream &OS, const PrintingPolicy &Policy, const Twine &PlaceHolder=Twine(), unsigned Indentation=0) const
Definition: Type.h:994
bool operator==(CanQual< T > x, CanQual< U > y)
Expr * getCond()
Definition: Stmt.h:1131
DOTGraphTraits(bool isSimple=false)
Definition: CFG.cpp:5067
ElementList::iterator iterator
Definition: CFG.h:655
succ_iterator succ_begin()
Definition: CFG.h:711
CompoundStmt * getSubStmt()
Definition: Expr.h:3517
DominatorTree GraphTraits specialization so the DominatorTree can be iterable by generic graph iterat...
Definition: Dominators.h:26
bool isReachable() const
Definition: CFG.h:622
const DeclStmt * getConditionVariableDeclStmt() const
If this ForStmt has a condition variable, return the faux DeclStmt associated with the creation of th...
Definition: Stmt.h:1236
Stmt - This represents one statement.
Definition: Stmt.h:66
FunctionType - C99 6.7.5.3 - Function Declarators.
Definition: Type.h:3062
CXXCatchStmt * getHandler(unsigned i)
Definition: StmtCXX.h:104
CFGBlock & getEntry()
Definition: CFG.h:1014
IfStmt - This represents an if/then/else.
Definition: Stmt.h:933
QualType getPointeeType() const
If this is a pointer, ObjC object pointer, or block pointer, this returns the respective pointee...
Definition: Type.cpp:456
StorageClass getStorageClass() const
Returns the storage class as written in the source.
Definition: Decl.h:1014
C Language Family Type Representation.
bool isRecordType() const
Definition: Type.h:6021
Expr * getBase() const
Definition: Expr.h:2490
unsigned getBlockID() const
Definition: CFG.h:816
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:86
Stmt * getHandlerBlock() const
Definition: StmtCXX.h:52
static QualType getReferenceInitTemporaryType(ASTContext &Context, const Expr *Init, bool *FoundMTE=nullptr)
Retrieve the type of the temporary object whose lifetime was extended by a local reference with the g...
Definition: CFG.cpp:1328
Opcode getOpcode() const
Definition: Expr.h:3039
StringRef P
void appendNewAllocator(CXXNewExpr *NE, BumpVectorContext &C)
Definition: CFG.h:847
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:5897
void appendLifetimeEnds(VarDecl *VD, Stmt *S, BumpVectorContext &C)
Definition: CFG.h:868
The base class of the type hierarchy.
Definition: Type.h:1356
Represents Objective-C&#39;s @throw statement.
Definition: StmtObjC.h:313
CFGDeleteDtor - Represents C++ object destructor generated from a call to delete. ...
Definition: CFG.h:366
Represents an array type, per C99 6.7.5.2 - Array Declarators.
Definition: Type.h:2564
iterator begin()
Definition: CFG.h:663
Represents a call to a C++ constructor.
Definition: ExprCXX.h:1239
unsigned IgnoreDefaultsWithCoveredEnums
Definition: CFG.h:739
Represents a C++ constructor within a class.
Definition: DeclCXX.h:2452
Represents a prvalue temporary that is written into memory so that a reference can bind to it...
Definition: ExprCXX.h:4039
float __ovld __cnfn distance(float p0, float p1)
Returns the distance between p0 and p1.
bool isCompleteDefinition() const
Return true if this decl has its body fully specified.
Definition: Decl.h:3119
VarDecl * getConditionVariable() const
Retrieve the variable declared in this "while" statement, if any.
Definition: Stmt.cpp:900
unsigned succ_size() const
Definition: CFG.h:729
const CXXDestructorDecl * getDestructorDecl(ASTContext &astContext) const
Definition: CFG.cpp:4280
Stmt * getSubStmt()
Definition: Stmt.h:814
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:1840
bool EvaluateAsInt(llvm::APSInt &Result, const ASTContext &Ctx, SideEffectsKind AllowSideEffects=SE_NoSideEffects) const
EvaluateAsInt - Return true if this is a constant which we can fold and convert to an integer...
Represents a variable declaration or definition.
Definition: Decl.h:812
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6317
CFGBlock * getReachableBlock() const
Get the reachable block, if one exists.
Definition: CFG.h:599
const char * getName() const
Definition: Stmt.cpp:332
Describes how types, statements, expressions, and declarations should be printed. ...
Definition: PrettyPrinter.h:38
Defines the Objective-C statement AST node classes.
static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper, const CFGElement &E)
Definition: CFG.cpp:4638
A C++ throw-expression (C++ [except.throw]).
Definition: ExprCXX.h:985
Represents an expression – generally a full-expression – that introduces cleanups to be run at the ...
Definition: ExprCXX.h:3003
static bool isAssignmentOp(Opcode Opc)
Definition: Expr.h:3121
Defines the clang::Expr interface and subclasses for C++ expressions.
VarDecl * getConditionVariable() const
Retrieve the variable declared in this "switch" statement, if any.
Definition: Stmt.cpp:866
const Stmt * getSubStmt() const
Definition: StmtObjC.h:356
const char * getStmtClassName() const
Definition: Stmt.cpp:74
LabelStmt - Represents a label, which has a substatement.
Definition: Stmt.h:842
const AstTypeMatcher< RecordType > recordType
Matches record types (e.g.
static TryResult bothKnownTrue(TryResult R1, TryResult R2)
Definition: CFG.cpp:373
bool pred_empty() const
Definition: CFG.h:733
Stmt * getBody()
Definition: Stmt.h:1179
CFGBlock * getPossiblyUnreachableBlock() const
Get the potentially unreachable block.
Definition: CFG.h:604
void print(raw_ostream &Out, unsigned Indentation=0, bool PrintInstantiation=false) const
QualType getPointeeType() const
Definition: Type.h:2406
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:149
void setLoopTarget(const Stmt *loopTarget)
Definition: CFG.h:797
static std::string getNodeLabel(const CFGBlock *Node, const CFG *Graph)
Definition: CFG.cpp:5069
field_range fields() const
Definition: Decl.h:3639
Represents a member of a struct/union/class.
Definition: Decl.h:2488
TypeSourceInfo * getTypeSourceInfo() const
Returns the declarator information for a base class or delegating initializer.
Definition: DeclCXX.h:2354
iterator insertAutomaticObjDtor(iterator I, VarDecl *VD, Stmt *S)
Definition: CFG.h:888
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:4975
CFGAutomaticObjDtor - Represents C++ object destructor implicitly generated for automatic object or t...
Definition: CFG.h:340
const Expr * getRetValue() const
Definition: Stmt.cpp:928
void appendAutomaticObjDtor(VarDecl *VD, Stmt *S, BumpVectorContext &C)
Definition: CFG.h:864
bool isReferenceType() const
Definition: Type.h:5960
const CXXConstructExpr * getConstructExpr() const
Returns the CXXConstructExpr from this new-expression, or null.
Definition: ExprCXX.h:1998
clang::CharUnits operator*(clang::CharUnits::QuantityType Scale, const clang::CharUnits &CU)
Definition: CharUnits.h:208
bool isAllEnumCasesCovered() const
Returns true if the SwitchStmt is a switch of an enum value and all cases have been explicitly covere...
Definition: Stmt.h:1083
Expr * getSubExpr()
Definition: Expr.h:2774
void setTerminator(CFGTerminator Term)
Definition: CFG.h:795
Keeps track of the various options that can be enabled, which controls the dialect of C or C++ that i...
Definition: LangOptions.h:50
iterator end()
Definition: CFG.h:1000
Represents Objective-C&#39;s @catch statement.
Definition: StmtObjC.h:74
AdjacentBlocks::const_iterator const_succ_iterator
Definition: CFG.h:687
IndirectGotoStmt - This represents an indirect goto.
Definition: Stmt.h:1312
Describes an C or C++ initializer list.
Definition: Expr.h:3885
bool EvaluateAsBooleanCondition(bool &Result, const ASTContext &Ctx) const
EvaluateAsBooleanCondition - Return true if this is a constant which we we can fold and convert to a ...
BinaryOperatorKind
Expr * getArraySize()
Definition: ExprCXX.h:1952
ForStmt - This represents a &#39;for (init;cond;inc)&#39; stmt.
Definition: Stmt.h:1207
APValue Val
Val - This is the value the expression can be folded to.
Definition: Expr.h:573
LabelDecl * getDecl() const
Definition: Stmt.h:859
Forward-declares and imports various common LLVM datatypes that clang wants to use unqualified...
capture_init_iterator capture_init_begin()
Retrieve the first initialization argument for this lambda expression (which initializes the first ca...
Definition: ExprCXX.h:1728
Expr * getInitializer()
The initializer of this new-expression.
Definition: ExprCXX.h:1990
Stmt * getBody()
Definition: Stmt.h:1242
CFGCallback * Observer
Definition: CFG.h:939
child_range children()
Definition: Stmt.cpp:226
A builtin binary operation expression such as "x + y" or "x <= y".
Definition: Expr.h:2998
Stmt * getInit()
Definition: Stmt.h:1221
bool isNull() const
Definition: CFG.h:163
CXXForRangeStmt - This represents C++0x [stmt.ranged]&#39;s ranged for statement, represented as &#39;for (ra...
Definition: StmtCXX.h:128
static bool areExprTypesCompatible(const Expr *E1, const Expr *E2)
For an expression x == Foo && x == Bar, this determines whether the Foo and Bar are either of the sam...
Definition: CFG.cpp:120
void print(raw_ostream &OS, const CFG *cfg, const LangOptions &LO, bool ShowColors) const
print - A simple pretty printer of a CFGBlock that outputs to an ostream.
Definition: CFG.cpp:4967
void printPretty(raw_ostream &OS, PrinterHelper *Helper, const PrintingPolicy &Policy, unsigned Indentation=0, const ASTContext *Context=nullptr) const
Scope - A scope is a transient data structure that is used while parsing the program.
Definition: Scope.h:39
const Type * getTypePtr() const
Retrieves a pointer to the underlying (unqualified) type.
Definition: Type.h:5724
void appendLoopExit(const Stmt *LoopStmt, BumpVectorContext &C)
Definition: CFG.h:872
Expr * getCond()
Definition: Stmt.h:1240
bool isInt() const
Definition: APValue.h:183
CastExpr - Base class for type casts, including both implicit casts (ImplicitCastExpr) and explicit c...
Definition: Expr.h:2723
Represents binding an expression to a temporary.
Definition: ExprCXX.h:1196
CXXTemporary * getTemporary()
Definition: ExprCXX.h:1215
FieldDecl * getAnyMember() const
Definition: DeclCXX.h:2366
A C++ lambda expression, which produces a function object (of unspecified type) that can be invoked l...
Definition: ExprCXX.h:1583
bool hasTrivialDestructor() const
Determine whether this class has a trivial destructor (C++ [class.dtor]p3)
Definition: DeclCXX.h:1437
bool isTypeDependent() const
isTypeDependent - Determines whether this expression is type-dependent (C++ [temp.dep.expr]), which means that its type could change from one template instantiation to the next.
Definition: Expr.h:167
child_range children()
Definition: Stmt.h:691
CXXDestructorDecl * getDestructor() const
Returns the destructor decl for this class.
Definition: DeclCXX.cpp:1515
VarDecl * getConditionVariable() const
Retrieve the variable declared in this "for" statement, if any.
Definition: Stmt.cpp:838
bool getNoReturn() const
Definition: Type.h:3132
Stmt * getInit()
Definition: Stmt.h:966
arg_iterator placement_arg_end()
Definition: ExprCXX.h:2029
Iterator for iterating over Stmt * arrays that contain only Expr *.
Definition: Stmt.h:332
llvm::DenseMap< const Stmt *, const CFGBlock * > ForcedBlkExprs
Definition: CFG.h:936
CFGBlockListTy::const_iterator const_iterator
Definition: CFG.h:992
CFG * getParent() const
Definition: CFG.h:818
CompoundStmt - This represents a group of statements like { stmt stmt }.
Definition: Stmt.h:595
CXXRecordDecl * getAsCXXRecordDecl() const
Retrieves the CXXRecordDecl that this type refers to, either because the type is a RecordType or beca...
Definition: Type.cpp:1590
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3274
bool isDelegatingInitializer() const
Determine whether this initializer is creating a delegating constructor.
Definition: DeclCXX.h:2321
UnaryExprOrTypeTraitExpr - expression with either a type or (unevaluated) expression operand...
Definition: Expr.h:2040
void appendBaseDtor(const CXXBaseSpecifier *BS, BumpVectorContext &C)
Definition: CFG.h:852
static bool shouldAddCase(bool &switchExclusivelyCovered, const Expr::EvalResult *switchCond, const CaseStmt *CS, ASTContext &Ctx)
Definition: CFG.cpp:3558
CFGBlock - Represents a single basic block in a source-level CFG.
Definition: CFG.h:509
const DeclStmt * getConditionVariableDeclStmt() const
If this IfStmt has a condition variable, return the faux DeclStmt associated with the creation of tha...
Definition: Stmt.h:962
llvm::APSInt EvaluateKnownConstInt(const ASTContext &Ctx, SmallVectorImpl< PartialDiagnosticAt > *Diag=nullptr) const
EvaluateKnownConstInt - Call EvaluateAsRValue and return the folded integer.
bool isNoReturn(ASTContext &astContext) const
Definition: CFG.cpp:4334
Expr - This represents one expression.
Definition: Expr.h:106
Defines the clang::LangOptions interface.
Stmt * getTerminatorCondition(bool StripParens=true)
Definition: CFG.cpp:4981
static std::tuple< const DeclRefExpr *, BinaryOperatorKind, const Expr * > tryNormalizeBinaryOperator(const BinaryOperator *B)
Tries to interpret a binary operator into Decl Op Expr form, if Expr is an integer literal or an enum...
Definition: CFG.cpp:89
DeclStmt * getEndStmt()
Definition: StmtCXX.h:158
SourceLocation End
std::string Label
CFG - Represents a source-level, intra-procedural CFG that represents the control-flow of a Stmt...
Definition: CFG.h:926
const FunctionProtoType * T
Represents a C++ functional cast expression that builds a temporary object.
Definition: ExprCXX.h:1533
const Stmt * getThen() const
Definition: Stmt.h:971
BlockExpr - Adaptor class for mixing a BlockDecl with expressions.
Definition: Expr.h:4864
Represents a C++ destructor within a class.
Definition: DeclCXX.h:2675
bool succ_empty() const
Definition: CFG.h:730
VarDecl * getExceptionDecl() const
Definition: StmtCXX.h:50
unsigned getNumInits() const
Definition: Expr.h:3915
const Expr * getCallee() const
Definition: Expr.h:2258
CFGConstructor - Represents C++ constructor call.
Definition: CFG.h:185
QualType getArgumentType() const
Definition: Expr.h:2077
#define bool
Definition: stdbool.h:31
Stmt * getBody()
Definition: Stmt.h:1134
const CompoundStmt * getSynchBody() const
Definition: StmtObjC.h:282
ElementList::const_iterator const_iterator
Definition: CFG.h:656
Expr * getRHS()
Definition: Stmt.h:765
bool isTemporaryDtorsBranch() const
Definition: CFG.h:470
Represents Objective-C&#39;s @synchronized statement.
Definition: StmtObjC.h:262
SourceLocation Begin
CXXTryStmt - A C++ try block, including all handlers.
Definition: StmtCXX.h:65
const AstTypeMatcher< ArrayType > arrayType
Matches all kinds of arrays.
std::reverse_iterator< body_iterator > reverse_body_iterator
Definition: Stmt.h:659
QualType getType() const
Definition: Expr.h:128
static void print_initializer(raw_ostream &OS, StmtPrinterHelper &Helper, const CXXCtorInitializer *I)
Definition: CFG.cpp:4617
LabelDecl * getLabel() const
Definition: Stmt.h:1290
StorageDuration getStorageDuration() const
Retrieve the storage duration for the materialized temporary.
Definition: ExprCXX.h:4083
ReturnStmt - This represents a return, optionally of an expression: return; return 4;...
Definition: Stmt.h:1417
UnaryOperator - This represents the unary-expression&#39;s (except sizeof and alignof), the postinc/postdec operators from postfix-expression, and various extensions.
Definition: Expr.h:1717
static bool CanThrow(Expr *E, ASTContext &Ctx)
Definition: CFG.cpp:2093
const Type * getBaseElementTypeUnsafe() const
Get the base element type of this type, potentially discarding type qualifiers.
Definition: Type.h:6275
ValueDecl * getDecl()
Definition: Expr.h:1041
CFGBaseDtor - Represents C++ object destructor implicitly generated for base object in destructor...
Definition: CFG.h:392
The result type of a method or function.
QualType getDestroyedType() const
Retrieve the type being destroyed.
Definition: ExprCXX.cpp:178
const Expr * getSubExpr() const
Definition: ExprCXX.h:1219
bool isNull() const
Return true if this QualType doesn&#39;t point to a type yet.
Definition: Type.h:719
DoStmt - This represents a &#39;do/while&#39; stmt.
Definition: Stmt.h:1158
std::reverse_iterator< decl_iterator > reverse_decl_iterator
Definition: Stmt.h:543
RecordDecl * getDecl() const
Definition: Type.h:3992
Expr * getArgument()
Definition: ExprCXX.h:2128
void appendStmt(Stmt *statement, BumpVectorContext &C)
Definition: CFG.h:833
CFGTerminator getTerminator()
Definition: CFG.h:800
OpaqueValueExpr - An expression referring to an opaque object of a fixed type and value class...
Definition: Expr.h:868
Kind
PseudoObjectExpr - An expression which accesses a pseudo-object l-value.
Definition: Expr.h:4982
Encodes a location in the source.
Stmt * getLabel()
Definition: CFG.h:811
unsigned getNumHandlers() const
Definition: StmtCXX.h:103
Expr * getSubExpr() const
Definition: Expr.h:1744
Represents a C++ temporary.
Definition: ExprCXX.h:1164
const SwitchCase * getSwitchCaseList() const
Definition: Stmt.h:1051
Represents a new-expression for memory allocation and constructor calls, e.g: "new CXXNewExpr(foo)"...
Definition: ExprCXX.h:1845
Expr * getLHS()
Definition: Stmt.h:764
void setLabel(Stmt *Statement)
Definition: CFG.h:796
static std::unique_ptr< CFG > buildCFG(const Decl *D, Stmt *AST, ASTContext *C, const BuildOptions &BO)
buildCFG - Builds a CFG from an AST.
Definition: CFG.cpp:4273
DeclStmt - Adaptor class for mixing declarations with statements and expressions. ...
Definition: Stmt.h:487
bool PruneTriviallyFalseEdges
Definition: CFG.h:940
reverse_body_iterator body_rend()
Definition: Stmt.h:665
QualType getBaseElementType(const ArrayType *VAT) const
Return the innermost element type of an array type.
const ConstantArrayType * getAsConstantArrayType(QualType T) const
Definition: ASTContext.h:2332
virtual void compareAlwaysTrue(const BinaryOperator *B, bool isAlwaysTrue)
Definition: CFG.h:914
StmtVisitor - This class implements a simple visitor for Stmt subclasses.
Definition: StmtVisitor.h:186
static void print_block(raw_ostream &OS, const CFG *cfg, const CFGBlock &B, StmtPrinterHelper &Helper, bool print_edges, bool ShowColors)
Definition: CFG.cpp:4748
const ArrayType * getAsArrayType(QualType T) const
Type Query functions.
bool isArray() const
Definition: ExprCXX.h:1950
decl_iterator decl_begin()
Definition: Stmt.h:538
bool isValueDependent() const
isValueDependent - Determines whether this expression is value-dependent (C++ [temp.dep.constexpr]).
Definition: Expr.h:149
bool isKnownToHaveBooleanValue() const
isKnownToHaveBooleanValue - Return true if this is an integer expression that is known to return 0 or...
Definition: Expr.cpp:135
reverse_decl_iterator decl_rbegin()
Definition: Stmt.h:545
ImplicitCastExpr - Allows us to explicitly represent implicit type conversions, which have no direct ...
Definition: Expr.h:2835
static QualType findBoundMemberType(const Expr *expr)
Given an expression of bound-member type, find the type of the member.
Definition: Expr.cpp:2410
Expr ** getInits()
Retrieve the set of initializers.
Definition: Expr.h:3918
iterator begin()
Definition: CFG.h:999
static bool isLogicalOp(Opcode Opc)
Definition: Expr.h:3118
static const Expr * tryTransformToIntOrEnumConstant(const Expr *E)
Helper for tryNormalizeBinaryOperator.
Definition: CFG.cpp:74
void dump() const
Definition: CFG.cpp:4961
succ_iterator succ_end()
Definition: CFG.h:712
StmtExpr - This is the GNU Statement Expression extension: ({int X=4; X;}).
Definition: Expr.h:3501
bool isArgumentType() const
Definition: Expr.h:2076
const DeclStmt * getConditionVariableDeclStmt() const
If this WhileStmt has a condition variable, return the faux DeclStmt associated with the creation of ...
Definition: Stmt.h:1127
Optional< T > getAs() const
Convert to the specified CFGElement type, returning None if this CFGElement is not of the desired typ...
Definition: CFG.h:105
Expr * getLHS() const
Definition: Expr.h:3042
Defines various enumerations that describe declaration and type specifiers.
AddrLabelExpr - The GNU address of label extension, representing &&label.
Definition: Expr.h:3457
ast_type_traits::DynTypedNode Node
pred_iterator pred_begin()
Definition: CFG.h:693
OpaqueValueExpr * getOpaqueValue() const
getOpaqueValue - Return the opaque value placeholder.
Definition: Expr.h:3398
VarDecl * getConditionVariable() const
Retrieve the variable declared in this "if" statement, if any.
Definition: Stmt.cpp:803
Dataflow Directional Tag Classes.
child_range children()
llvm::PointerUnion< Stmt *, CXXCtorInitializer * > TriggerTy
Definition: CFG.h:149
DeclContext - This is used only as base class of specific decl types that can act as declaration cont...
Definition: DeclBase.h:1256
EvalResult is a struct with detailed info about an evaluated expression.
Definition: Expr.h:571
Represents a delete expression for memory deallocation and destructor calls, e.g. ...
Definition: ExprCXX.h:2074
ArrayRef< Capture > captures() const
Definition: Decl.h:3839
iterator beginAutomaticObjDtorsInsert(iterator I, size_t Cnt, BumpVectorContext &C)
Definition: CFG.h:883
virtual void compareBitwiseEquality(const BinaryOperator *B, bool isAlwaysTrue)
Definition: CFG.h:915
FunctionDecl * getDirectCallee()
If the callee is a FunctionDecl, return it. Otherwise return 0.
Definition: Expr.cpp:1216
void appendConstructor(CXXConstructExpr *CE, const ConstructionContext &CC, BumpVectorContext &C)
Definition: CFG.h:837
const Stmt * stripLabelLikeStatements() const
Strip off all label-like statements.
Definition: Stmt.cpp:154
static const VariableArrayType * FindVA(const Type *t)
Definition: CFG.cpp:1139
const Expr * getInit() const
Definition: Decl.h:1214
unsigned pred_size() const
Definition: CFG.h:732
StmtClass getStmtClass() const
Definition: Stmt.h:378
static StmtPrinterHelper * GraphHelper
Definition: CFG.cpp:5051
void appendDeleteDtor(CXXRecordDecl *RD, CXXDeleteExpr *DE, BumpVectorContext &C)
Definition: CFG.h:876
const CXXRecordDecl * getParent() const
Returns the parent of this method declaration, which is the class in which this method is defined...
Definition: DeclCXX.h:2140
bool isAnyDestructorNoReturn() const
Returns true if the class destructor, or any implicitly invoked destructors are marked noreturn...
Definition: DeclCXX.cpp:1528
const Type * getBaseClass() const
If this is a base class initializer, returns the type of the base class.
Definition: DeclCXX.cpp:2069
SEHExceptStmt * getExceptHandler() const
Returns 0 if not defined.
Definition: Stmt.cpp:948
const Decl * getSingleDecl() const
Definition: Stmt.h:504
FunctionType::ExtInfo getFunctionExtInfo(const Type &t)
Definition: Type.h:5849
const Expr * getSynchExpr() const
Definition: StmtObjC.h:290
void appendMemberDtor(FieldDecl *FD, BumpVectorContext &C)
Definition: CFG.h:856
void appendInitializer(CXXCtorInitializer *initializer, BumpVectorContext &C)
Definition: CFG.h:842
This class represents a potential adjacent block in the CFG.
Definition: CFG.h:580
bool isSingleDecl() const
isSingleDecl - This method returns true if this DeclStmt refers to a single Decl. ...
Definition: Stmt.h:500
Represents the point where the lifetime of an automatic object ends.
Definition: CFG.h:290
Stmt * getStmt()
Definition: CFG.h:467
Expr * IgnoreParenImpCasts() LLVM_READONLY
IgnoreParenImpCasts - Ignore parentheses and implicit casts.
Definition: Expr.cpp:2552
const Stmt * getBody() const
Definition: Stmt.h:1050
llvm::APInt getValue() const
Definition: Expr.h:1279
Represents a __leave statement.
Definition: Stmt.h:2023
LabelDecl * getLabel() const
Definition: Expr.h:3479
SwitchStmt - This represents a &#39;switch&#39; stmt.
Definition: Stmt.h:1011
Pointer to a block type.
Definition: Type.h:2391
CFGBlock * getIndirectGotoBlock()
Definition: CFG.h:1019
A helper class that allows the use of isa/cast/dyncast to detect TagType objects of structs/unions/cl...
Definition: Type.h:3982
bool body_empty() const
Definition: Stmt.h:620
Represents Objective-C&#39;s collection statement.
Definition: StmtObjC.h:24
AbstractConditionalOperator - An abstract base class for ConditionalOperator and BinaryConditionalOpe...
Definition: Expr.h:3240
Represents a C++ base or member initializer.
Definition: DeclCXX.h:2227
reverse_decl_iterator decl_rend()
Definition: Stmt.h:549
Stmt * getInit()
Definition: Stmt.h:1046
iterator insertLifetimeEnds(iterator I, VarDecl *VD, Stmt *S)
Definition: CFG.h:901
Base for LValueReferenceType and RValueReferenceType.
Definition: Type.h:2425
void print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const
print - A simple pretty printer of a CFG that outputs to an ostream.
Definition: CFG.cpp:4934
CanQualType BoundMemberTy
Definition: ASTContext.h:1013
decl_range decls()
Definition: Stmt.h:534
Represents a base class of a C++ class.
Definition: DeclCXX.h:191
arg_iterator placement_arg_begin()
Definition: ExprCXX.h:2026
DeclStmt * getRangeStmt()
Definition: StmtCXX.h:154
Expr * getRHS() const
Definition: Expr.h:3726
SEHFinallyStmt * getFinallyHandler() const
Definition: Stmt.cpp:952
GotoStmt - This represents a direct goto.
Definition: Stmt.h:1278
A use of a default initializer in a constructor or in aggregate initialization.
Definition: ExprCXX.h:1113
Expr * getTarget()
Definition: Stmt.h:1332
unsigned IgnoreNullPredecessors
Definition: CFG.h:738
bool hasNoReturnElement() const
Definition: CFG.h:814
X
Add a minimal nested name specifier fixit hint to allow lookup of a tag name from an outer enclosing ...
Definition: SemaDecl.cpp:13419
void setHasNoReturnElement()
Definition: CFG.h:798
Expr * getCond()
Definition: Stmt.h:1176
Defines the C++ Decl subclasses, other than those for templates (found in DeclTemplate.h) and friends (in DeclFriend.h).
MemberExpr - [C99 6.5.2.3] Structure and Union Members.
Definition: Expr.h:2400
void viewCFG(const LangOptions &LO) const
Definition: CFG.cpp:5054
Defines the clang::SourceLocation class and associated facilities.
Represents a C++ struct/union/class.
Definition: DeclCXX.h:299
ContinueStmt - This represents a continue.
Definition: Stmt.h:1355
reverse_body_iterator body_rbegin()
Definition: Stmt.h:661
ChooseExpr - GNU builtin-in function __builtin_choose_expr.
Definition: Expr.h:3677
Expr * getFilterExpr() const
Definition: Stmt.h:1924
BinaryConditionalOperator - The GNU extension to the conditional operator which allows the middle ope...
Definition: Expr.h:3355
CXXCatchStmt - This represents a C++ catch block.
Definition: StmtCXX.h:29
Represents an explicit C++ type conversion that uses "functional" notation (C++ [expr.type.conv]).
Definition: ExprCXX.h:1471
bool operator!=(CanQual< T > x, CanQual< U > y)
WhileStmt - This represents a &#39;while&#39; stmt.
Definition: Stmt.h:1102
CFGElement - Represents a top-level expression in a basic block.
Definition: CFG.h:54
void addSuccessor(AdjacentBlock Succ, BumpVectorContext &C)
Adds a (potentially unreachable) successor block to the current block.
Definition: CFG.cpp:4354
unsigned kind
All of the diagnostics that can be emitted by the frontend.
Definition: DiagnosticIDs.h:61
CFGTerminator - Represents CFGBlock terminator statement.
Definition: CFG.h:459
CompoundStmt * getTryBlock()
Definition: StmtCXX.h:96
bool AddRichCXXConstructors
Definition: CFG.h:950
CFGMemberDtor - Represents C++ object destructor implicitly generated for member object in destructor...
Definition: CFG.h:413
Represents Objective-C&#39;s @try ... @catch ... @finally statement.
Definition: StmtObjC.h:154
AdjacentBlock(CFGBlock *B, bool IsReachable)
Construct an AdjacentBlock with a possibly unreachable block.
Definition: CFG.cpp:4344
Full-expression storage duration (for temporaries).
Definition: Specifiers.h:274
CallExpr - Represents a function call (C99 6.5.2.2, C++ [expr.call]).
Definition: Expr.h:2218
void dump(const LangOptions &LO, bool ShowColors) const
dump - A simple pretty printer of a CFG that outputs to stderr.
Definition: CFG.cpp:4929
void appendTemporaryDtor(CXXBindTemporaryExpr *E, BumpVectorContext &C)
Definition: CFG.h:860
bool isBuiltinAssumeFalse(const ASTContext &Ctx) const
Return true if this is a call to __assume() or __builtin_assume() with a non-value-dependent constant...
Definition: Expr.cpp:2920
StringRef getName() const
Get the name of identifier for this declaration as a StringRef.
Definition: Decl.h:275
Expr * getLHS() const
Definition: Expr.h:3724
static Decl::Kind getKind(const Decl *D)
Definition: DeclBase.cpp:930
capture_init_iterator capture_init_end()
Retrieve the iterator pointing one past the last initialization argument for this lambda expression...
Definition: ExprCXX.h:1740
A reference to a declared variable, function, enum, etc.
Definition: Expr.h:956
Expr * getRHS() const
Definition: Expr.h:3044
unsigned IncludeNewlines
When true, include newlines after statements like "break", etc.
BreakStmt - This represents a break.
Definition: Stmt.h:1381
CFGInitializer - Represents C++ base or member initializer from constructor&#39;s initialization list...
Definition: CFG.h:225
Expr * getSemanticExpr(unsigned index)
Definition: Expr.h:5070
Stmt * getSubStmt()
Definition: Stmt.h:862
DeclStmt * getLoopVarStmt()
Definition: StmtCXX.h:161
QualType getType() const
Definition: Decl.h:647
bool isUnresolvedExceptionSpec(ExceptionSpecificationType ESpecType)
const Expr * getCond() const
Definition: Stmt.h:969
Represents a C array with a specified size that is not an integer-constant-expression.
Definition: Type.h:2723
iterator end()
Definition: CFG.h:664
APSInt & getInt()
Definition: APValue.h:201
CFGBlock * createBlock()
createBlock - Create a new block in the CFG.
Definition: CFG.cpp:4256
Expr * getCommon() const
getCommon - Return the common expression, written to the left of the condition.
Definition: Expr.h:3395
DeclStmt * getBeginStmt()
Definition: StmtCXX.h:155
const Expr * getCond() const
Definition: Stmt.h:1049
bool isFunctionPointerType() const
Definition: Type.h:5972
iterator beginLifetimeEndsInsert(iterator I, size_t Cnt, BumpVectorContext &C)
Definition: CFG.h:896
const LangOptions & getLangOpts() const
Definition: ASTContext.h:688
Represents Objective-C&#39;s @autoreleasepool Statement.
Definition: StmtObjC.h:345
Represents the canonical version of C arrays with a specified constant size.
Definition: Type.h:2624
base_class_range vbases()
Definition: DeclCXX.h:801
CompoundStmt * getTryBlock() const
Definition: Stmt.h:2003
CFGTemporaryDtor - Represents C++ object destructor implicitly generated at the end of full expressio...
Definition: CFG.h:434
static bool FilterEdge(const FilterOptions &F, const CFGBlock *Src, const CFGBlock *Dst)
Definition: CFG.cpp:4365
Defines enum values for all the target-independent builtin functions.
CompoundStmt * getBlock() const
Definition: Stmt.h:1928
SourceLocation getLocation() const
Definition: DeclBase.h:416
QualType getType() const
Return the type wrapped by this type source info.
Definition: Decl.h:97
Expr * IgnoreParens() LLVM_READONLY
IgnoreParens - Ignore parentheses.
Definition: Expr.cpp:2434
CFGBlock & getExit()
Definition: CFG.h:1016
Stmt * getSubStmt()
Definition: Stmt.h:766
const DeclStmt * getConditionVariableDeclStmt() const
If this SwitchStmt has a condition variable, return the faux DeclStmt associated with the creation of...
Definition: Stmt.h:1042
QualType getType() const
Retrieves the type of the base class.
Definition: DeclCXX.h:290
Represents the point where a loop ends.
Definition: CFG.h:271