1 //===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the CFG and CFGBuilder classes for representing and
11 // building Control-Flow Graphs (CFGs) from ASTs.
13 //===----------------------------------------------------------------------===//
15 #include "clang/Analysis/CFG.h"
16 #include "clang/AST/ASTContext.h"
17 #include "clang/AST/Attr.h"
18 #include "clang/AST/CharUnits.h"
19 #include "clang/AST/DeclCXX.h"
20 #include "clang/AST/PrettyPrinter.h"
21 #include "clang/AST/StmtVisitor.h"
22 #include "clang/Basic/Builtins.h"
23 #include "llvm/ADT/DenseMap.h"
25 #include "llvm/ADT/SmallPtrSet.h"
26 #include "llvm/Support/Allocator.h"
27 #include "llvm/Support/Format.h"
28 #include "llvm/Support/GraphWriter.h"
29 #include "llvm/Support/SaveAndRestore.h"
31 using namespace clang;
35 static SourceLocation GetEndLoc(Decl *D) {
36 if (VarDecl *VD = dyn_cast<VarDecl>(D))
37 if (Expr *Ex = VD->getInit())
38 return Ex->getSourceRange().getEnd();
39 return D->getLocation();
42 /// Helper for tryNormalizeBinaryOperator. Attempts to extract an IntegerLiteral
43 /// or EnumConstantDecl from the given Expr. If it fails, returns nullptr.
44 const Expr *tryTransformToIntOrEnumConstant(const Expr *E) {
45 E = E->IgnoreParens();
46 if (isa<IntegerLiteral>(E))
48 if (auto *DR = dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))
49 return isa<EnumConstantDecl>(DR->getDecl()) ? DR : nullptr;
53 /// Tries to interpret a binary operator into `Decl Op Expr` form, if Expr is
54 /// an integer literal or an enum constant.
56 /// If this fails, at least one of the returned DeclRefExpr or Expr will be
58 static std::tuple<const DeclRefExpr *, BinaryOperatorKind, const Expr *>
59 tryNormalizeBinaryOperator(const BinaryOperator *B) {
60 BinaryOperatorKind Op = B->getOpcode();
62 const Expr *MaybeDecl = B->getLHS();
63 const Expr *Constant = tryTransformToIntOrEnumConstant(B->getRHS());
64 // Expr looked like `0 == Foo` instead of `Foo == 0`
65 if (Constant == nullptr) {
76 MaybeDecl = B->getRHS();
77 Constant = tryTransformToIntOrEnumConstant(B->getLHS());
80 auto *D = dyn_cast<DeclRefExpr>(MaybeDecl->IgnoreParenImpCasts());
81 return std::make_tuple(D, Op, Constant);
84 /// For an expression `x == Foo && x == Bar`, this determines whether the
85 /// `Foo` and `Bar` are either of the same enumeration type, or both integer
88 /// It's an error to pass this arguments that are not either IntegerLiterals
89 /// or DeclRefExprs (that have decls of type EnumConstantDecl)
90 static bool areExprTypesCompatible(const Expr *E1, const Expr *E2) {
91 // User intent isn't clear if they're mixing int literals with enum
93 if (isa<IntegerLiteral>(E1) != isa<IntegerLiteral>(E2))
96 // Integer literal comparisons, regardless of literal type, are acceptable.
97 if (isa<IntegerLiteral>(E1))
100 // IntegerLiterals are handled above and only EnumConstantDecls are expected
102 assert(isa<DeclRefExpr>(E1) && isa<DeclRefExpr>(E2));
103 auto *Decl1 = cast<DeclRefExpr>(E1)->getDecl();
104 auto *Decl2 = cast<DeclRefExpr>(E2)->getDecl();
106 assert(isa<EnumConstantDecl>(Decl1) && isa<EnumConstantDecl>(Decl2));
107 const DeclContext *DC1 = Decl1->getDeclContext();
108 const DeclContext *DC2 = Decl2->getDeclContext();
110 assert(isa<EnumDecl>(DC1) && isa<EnumDecl>(DC2));
116 /// The CFG builder uses a recursive algorithm to build the CFG. When
117 /// we process an expression, sometimes we know that we must add the
118 /// subexpressions as block-level expressions. For example:
122 /// When processing the '||' expression, we know that exp1 and exp2
123 /// need to be added as block-level expressions, even though they
124 /// might not normally need to be. AddStmtChoice records this
125 /// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then
126 /// the builder has an option not to add a subexpression as a
127 /// block-level expression.
129 class AddStmtChoice {
131 enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 };
133 AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {}
135 bool alwaysAdd(CFGBuilder &builder,
136 const Stmt *stmt) const;
138 /// Return a copy of this object, except with the 'always-add' bit
139 /// set as specified.
140 AddStmtChoice withAlwaysAdd(bool alwaysAdd) const {
141 return AddStmtChoice(alwaysAdd ? AlwaysAdd : NotAlwaysAdd);
148 /// LocalScope - Node in tree of local scopes created for C++ implicit
149 /// destructor calls generation. It contains list of automatic variables
150 /// declared in the scope and link to position in previous scope this scope
153 /// The process of creating local scopes is as follows:
154 /// - Init CFGBuilder::ScopePos with invalid position (equivalent for null),
155 /// - Before processing statements in scope (e.g. CompoundStmt) create
156 /// LocalScope object using CFGBuilder::ScopePos as link to previous scope
157 /// and set CFGBuilder::ScopePos to the end of new scope,
158 /// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points
160 /// - For every normal (without jump) end of scope add to CFGBlock destructors
161 /// for objects in the current scope,
162 /// - For every jump add to CFGBlock destructors for objects
163 /// between CFGBuilder::ScopePos and local scope position saved for jump
164 /// target. Thanks to C++ restrictions on goto jumps we can be sure that
165 /// jump target position will be on the path to root from CFGBuilder::ScopePos
166 /// (adding any variable that doesn't need constructor to be called to
167 /// LocalScope can break this assumption),
171 typedef BumpVector<VarDecl*> AutomaticVarsTy;
173 /// const_iterator - Iterates local scope backwards and jumps to previous
174 /// scope on reaching the beginning of currently iterated scope.
175 class const_iterator {
176 const LocalScope* Scope;
178 /// VarIter is guaranteed to be greater then 0 for every valid iterator.
179 /// Invalid iterator (with null Scope) has VarIter equal to 0.
183 /// Create invalid iterator. Dereferencing invalid iterator is not allowed.
184 /// Incrementing invalid iterator is allowed and will result in invalid
187 : Scope(nullptr), VarIter(0) {}
189 /// Create valid iterator. In case when S.Prev is an invalid iterator and
190 /// I is equal to 0, this will create invalid iterator.
191 const_iterator(const LocalScope& S, unsigned I)
192 : Scope(&S), VarIter(I) {
193 // Iterator to "end" of scope is not allowed. Handle it by going up
194 // in scopes tree possibly up to invalid iterator in the root.
195 if (VarIter == 0 && Scope)
199 VarDecl *const* operator->() const {
200 assert (Scope && "Dereferencing invalid iterator is not allowed");
201 assert (VarIter != 0 && "Iterator has invalid value of VarIter member");
202 return &Scope->Vars[VarIter - 1];
204 VarDecl *operator*() const {
205 return *this->operator->();
208 const_iterator &operator++() {
212 assert (VarIter != 0 && "Iterator has invalid value of VarIter member");
218 const_iterator operator++(int) {
219 const_iterator P = *this;
224 bool operator==(const const_iterator &rhs) const {
225 return Scope == rhs.Scope && VarIter == rhs.VarIter;
227 bool operator!=(const const_iterator &rhs) const {
228 return !(*this == rhs);
231 explicit operator bool() const {
232 return *this != const_iterator();
235 int distance(const_iterator L);
238 friend class const_iterator;
241 BumpVectorContext ctx;
243 /// Automatic variables in order of declaration.
244 AutomaticVarsTy Vars;
245 /// Iterator to variable in previous scope that was declared just before
246 /// begin of this scope.
250 /// Constructs empty scope linked to previous scope in specified place.
251 LocalScope(BumpVectorContext ctx, const_iterator P)
252 : ctx(std::move(ctx)), Vars(this->ctx, 4), Prev(P) {}
254 /// Begin of scope in direction of CFG building (backwards).
255 const_iterator begin() const { return const_iterator(*this, Vars.size()); }
257 void addVar(VarDecl *VD) {
258 Vars.push_back(VD, ctx);
262 /// distance - Calculates distance from this to L. L must be reachable from this
263 /// (with use of ++ operator). Cost of calculating the distance is linear w.r.t.
264 /// number of scopes between this and L.
265 int LocalScope::const_iterator::distance(LocalScope::const_iterator L) {
267 const_iterator F = *this;
268 while (F.Scope != L.Scope) {
269 assert (F != const_iterator()
270 && "L iterator is not reachable from F iterator.");
274 D += F.VarIter - L.VarIter;
278 /// Structure for specifying position in CFG during its build process. It
279 /// consists of CFGBlock that specifies position in CFG and
280 /// LocalScope::const_iterator that specifies position in LocalScope graph.
281 struct BlockScopePosPair {
282 BlockScopePosPair() : block(nullptr) {}
283 BlockScopePosPair(CFGBlock *b, LocalScope::const_iterator scopePos)
284 : block(b), scopePosition(scopePos) {}
287 LocalScope::const_iterator scopePosition;
290 /// TryResult - a class representing a variant over the values
291 /// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool,
292 /// and is used by the CFGBuilder to decide if a branch condition
293 /// can be decided up front during CFG construction.
297 TryResult(bool b) : X(b ? 1 : 0) {}
298 TryResult() : X(-1) {}
300 bool isTrue() const { return X == 1; }
301 bool isFalse() const { return X == 0; }
302 bool isKnown() const { return X >= 0; }
309 TryResult bothKnownTrue(TryResult R1, TryResult R2) {
310 if (!R1.isKnown() || !R2.isKnown())
312 return TryResult(R1.isTrue() && R2.isTrue());
315 class reverse_children {
316 llvm::SmallVector<Stmt *, 12> childrenBuf;
317 ArrayRef<Stmt*> children;
319 reverse_children(Stmt *S);
321 typedef ArrayRef<Stmt*>::reverse_iterator iterator;
322 iterator begin() const { return children.rbegin(); }
323 iterator end() const { return children.rend(); }
327 reverse_children::reverse_children(Stmt *S) {
328 if (CallExpr *CE = dyn_cast<CallExpr>(S)) {
329 children = CE->getRawSubExprs();
332 switch (S->getStmtClass()) {
333 // Note: Fill in this switch with more cases we want to optimize.
334 case Stmt::InitListExprClass: {
335 InitListExpr *IE = cast<InitListExpr>(S);
336 children = llvm::makeArrayRef(reinterpret_cast<Stmt**>(IE->getInits()),
344 // Default case for all other statements.
345 for (Stmt *SubStmt : S->children())
346 childrenBuf.push_back(SubStmt);
348 // This needs to be done *after* childrenBuf has been populated.
349 children = childrenBuf;
352 /// CFGBuilder - This class implements CFG construction from an AST.
353 /// The builder is stateful: an instance of the builder should be used to only
354 /// construct a single CFG.
358 /// CFGBuilder builder;
359 /// std::unique_ptr<CFG> cfg = builder.buildCFG(decl, stmt1);
361 /// CFG construction is done via a recursive walk of an AST. We actually parse
362 /// the AST in reverse order so that the successor of a basic block is
363 /// constructed prior to its predecessor. This allows us to nicely capture
364 /// implicit fall-throughs without extra basic blocks.
367 typedef BlockScopePosPair JumpTarget;
368 typedef BlockScopePosPair JumpSource;
371 std::unique_ptr<CFG> cfg;
375 JumpTarget ContinueJumpTarget;
376 JumpTarget BreakJumpTarget;
377 CFGBlock *SwitchTerminatedBlock;
378 CFGBlock *DefaultCaseBlock;
379 CFGBlock *TryTerminatedBlock;
381 // Current position in local scope.
382 LocalScope::const_iterator ScopePos;
384 // LabelMap records the mapping from Label expressions to their jump targets.
385 typedef llvm::DenseMap<LabelDecl*, JumpTarget> LabelMapTy;
388 // A list of blocks that end with a "goto" that must be backpatched to their
389 // resolved targets upon completion of CFG construction.
390 typedef std::vector<JumpSource> BackpatchBlocksTy;
391 BackpatchBlocksTy BackpatchBlocks;
393 // A list of labels whose address has been taken (for indirect gotos).
394 typedef llvm::SmallPtrSet<LabelDecl*, 5> LabelSetTy;
395 LabelSetTy AddressTakenLabels;
398 const CFG::BuildOptions &BuildOpts;
400 // State to track for building switch statements.
401 bool switchExclusivelyCovered;
402 Expr::EvalResult *switchCond;
404 CFG::BuildOptions::ForcedBlkExprs::value_type *cachedEntry;
405 const Stmt *lastLookup;
407 // Caches boolean evaluations of expressions to avoid multiple re-evaluations
408 // during construction of branches for chained logical operators.
409 typedef llvm::DenseMap<Expr *, TryResult> CachedBoolEvalsTy;
410 CachedBoolEvalsTy CachedBoolEvals;
413 explicit CFGBuilder(ASTContext *astContext,
414 const CFG::BuildOptions &buildOpts)
415 : Context(astContext), cfg(new CFG()), // crew a new CFG
416 Block(nullptr), Succ(nullptr),
417 SwitchTerminatedBlock(nullptr), DefaultCaseBlock(nullptr),
418 TryTerminatedBlock(nullptr), badCFG(false), BuildOpts(buildOpts),
419 switchExclusivelyCovered(false), switchCond(nullptr),
420 cachedEntry(nullptr), lastLookup(nullptr) {}
422 // buildCFG - Used by external clients to construct the CFG.
423 std::unique_ptr<CFG> buildCFG(const Decl *D, Stmt *Statement);
425 bool alwaysAdd(const Stmt *stmt);
428 // Visitors to walk an AST and construct the CFG.
429 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc);
430 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc);
431 CFGBlock *VisitBreakStmt(BreakStmt *B);
432 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc);
433 CFGBlock *VisitCaseStmt(CaseStmt *C);
434 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc);
435 CFGBlock *VisitCompoundStmt(CompoundStmt *C);
436 CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C,
438 CFGBlock *VisitContinueStmt(ContinueStmt *C);
439 CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
441 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S);
442 CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc);
443 CFGBlock *VisitCXXNewExpr(CXXNewExpr *DE, AddStmtChoice asc);
444 CFGBlock *VisitCXXDeleteExpr(CXXDeleteExpr *DE, AddStmtChoice asc);
445 CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S);
446 CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
448 CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
450 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T);
451 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S);
452 CFGBlock *VisitDeclStmt(DeclStmt *DS);
453 CFGBlock *VisitDeclSubExpr(DeclStmt *DS);
454 CFGBlock *VisitDefaultStmt(DefaultStmt *D);
455 CFGBlock *VisitDoStmt(DoStmt *D);
456 CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, AddStmtChoice asc);
457 CFGBlock *VisitForStmt(ForStmt *F);
458 CFGBlock *VisitGotoStmt(GotoStmt *G);
459 CFGBlock *VisitIfStmt(IfStmt *I);
460 CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc);
461 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I);
462 CFGBlock *VisitLabelStmt(LabelStmt *L);
463 CFGBlock *VisitBlockExpr(BlockExpr *E, AddStmtChoice asc);
464 CFGBlock *VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc);
465 CFGBlock *VisitLogicalOperator(BinaryOperator *B);
466 std::pair<CFGBlock *, CFGBlock *> VisitLogicalOperator(BinaryOperator *B,
469 CFGBlock *FalseBlock);
470 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc);
471 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S);
472 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S);
473 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S);
474 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S);
475 CFGBlock *VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S);
476 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S);
477 CFGBlock *VisitPseudoObjectExpr(PseudoObjectExpr *E);
478 CFGBlock *VisitReturnStmt(ReturnStmt *R);
479 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc);
480 CFGBlock *VisitSwitchStmt(SwitchStmt *S);
481 CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
483 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc);
484 CFGBlock *VisitWhileStmt(WhileStmt *W);
486 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd);
487 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc);
488 CFGBlock *VisitChildren(Stmt *S);
489 CFGBlock *VisitNoRecurse(Expr *E, AddStmtChoice asc);
491 /// When creating the CFG for temporary destructors, we want to mirror the
492 /// branch structure of the corresponding constructor calls.
493 /// Thus, while visiting a statement for temporary destructors, we keep a
494 /// context to keep track of the following information:
495 /// - whether a subexpression is executed unconditionally
496 /// - if a subexpression is executed conditionally, the first
497 /// CXXBindTemporaryExpr we encounter in that subexpression (which
498 /// corresponds to the last temporary destructor we have to call for this
499 /// subexpression) and the CFG block at that point (which will become the
500 /// successor block when inserting the decision point).
502 /// That way, we can build the branch structure for temporary destructors as
504 /// 1. If a subexpression is executed unconditionally, we add the temporary
505 /// destructor calls to the current block.
506 /// 2. If a subexpression is executed conditionally, when we encounter a
507 /// CXXBindTemporaryExpr:
508 /// a) If it is the first temporary destructor call in the subexpression,
509 /// we remember the CXXBindTemporaryExpr and the current block in the
510 /// TempDtorContext; we start a new block, and insert the temporary
512 /// b) Otherwise, add the temporary destructor call to the current block.
513 /// 3. When we finished visiting a conditionally executed subexpression,
514 /// and we found at least one temporary constructor during the visitation
515 /// (2.a has executed), we insert a decision block that uses the
516 /// CXXBindTemporaryExpr as terminator, and branches to the current block
517 /// if the CXXBindTemporaryExpr was marked executed, and otherwise
518 /// branches to the stored successor.
519 struct TempDtorContext {
521 : IsConditional(false), KnownExecuted(true), Succ(nullptr),
522 TerminatorExpr(nullptr) {}
524 TempDtorContext(TryResult KnownExecuted)
525 : IsConditional(true), KnownExecuted(KnownExecuted), Succ(nullptr),
526 TerminatorExpr(nullptr) {}
528 /// Returns whether we need to start a new branch for a temporary destructor
529 /// call. This is the case when the temporary destructor is
530 /// conditionally executed, and it is the first one we encounter while
531 /// visiting a subexpression - other temporary destructors at the same level
532 /// will be added to the same block and are executed under the same
534 bool needsTempDtorBranch() const {
535 return IsConditional && !TerminatorExpr;
538 /// Remember the successor S of a temporary destructor decision branch for
539 /// the corresponding CXXBindTemporaryExpr E.
540 void setDecisionPoint(CFGBlock *S, CXXBindTemporaryExpr *E) {
545 const bool IsConditional;
546 const TryResult KnownExecuted;
548 CXXBindTemporaryExpr *TerminatorExpr;
551 // Visitors to walk an AST and generate destructors of temporaries in
553 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary,
554 TempDtorContext &Context);
555 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E, TempDtorContext &Context);
556 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E,
557 TempDtorContext &Context);
558 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(
559 CXXBindTemporaryExpr *E, bool BindToTemporary, TempDtorContext &Context);
560 CFGBlock *VisitConditionalOperatorForTemporaryDtors(
561 AbstractConditionalOperator *E, bool BindToTemporary,
562 TempDtorContext &Context);
563 void InsertTempDtorDecisionBlock(const TempDtorContext &Context,
564 CFGBlock *FalseSucc = nullptr);
566 // NYS == Not Yet Supported
572 void autoCreateBlock() { if (!Block) Block = createBlock(); }
573 CFGBlock *createBlock(bool add_successor = true);
574 CFGBlock *createNoReturnBlock();
576 CFGBlock *addStmt(Stmt *S) {
577 return Visit(S, AddStmtChoice::AlwaysAdd);
579 CFGBlock *addInitializer(CXXCtorInitializer *I);
580 void addAutomaticObjDtors(LocalScope::const_iterator B,
581 LocalScope::const_iterator E, Stmt *S);
582 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD);
584 // Local scopes creation.
585 LocalScope* createOrReuseLocalScope(LocalScope* Scope);
587 void addLocalScopeForStmt(Stmt *S);
588 LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS,
589 LocalScope* Scope = nullptr);
590 LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = nullptr);
592 void addLocalScopeAndDtors(Stmt *S);
594 // Interface to CFGBlock - adding CFGElements.
595 void appendStmt(CFGBlock *B, const Stmt *S) {
596 if (alwaysAdd(S) && cachedEntry)
597 cachedEntry->second = B;
599 // All block-level expressions should have already been IgnoreParens()ed.
600 assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S);
601 B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext());
603 void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) {
604 B->appendInitializer(I, cfg->getBumpVectorContext());
606 void appendNewAllocator(CFGBlock *B, CXXNewExpr *NE) {
607 B->appendNewAllocator(NE, cfg->getBumpVectorContext());
609 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) {
610 B->appendBaseDtor(BS, cfg->getBumpVectorContext());
612 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) {
613 B->appendMemberDtor(FD, cfg->getBumpVectorContext());
615 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) {
616 B->appendTemporaryDtor(E, cfg->getBumpVectorContext());
618 void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) {
619 B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext());
622 void appendDeleteDtor(CFGBlock *B, CXXRecordDecl *RD, CXXDeleteExpr *DE) {
623 B->appendDeleteDtor(RD, DE, cfg->getBumpVectorContext());
626 void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
627 LocalScope::const_iterator B, LocalScope::const_iterator E);
629 void addSuccessor(CFGBlock *B, CFGBlock *S, bool IsReachable = true) {
630 B->addSuccessor(CFGBlock::AdjacentBlock(S, IsReachable),
631 cfg->getBumpVectorContext());
634 /// Add a reachable successor to a block, with the alternate variant that is
636 void addSuccessor(CFGBlock *B, CFGBlock *ReachableBlock, CFGBlock *AltBlock) {
637 B->addSuccessor(CFGBlock::AdjacentBlock(ReachableBlock, AltBlock),
638 cfg->getBumpVectorContext());
641 /// \brief Find a relational comparison with an expression evaluating to a
642 /// boolean and a constant other than 0 and 1.
643 /// e.g. if ((x < y) == 10)
644 TryResult checkIncorrectRelationalOperator(const BinaryOperator *B) {
645 const Expr *LHSExpr = B->getLHS()->IgnoreParens();
646 const Expr *RHSExpr = B->getRHS()->IgnoreParens();
648 const IntegerLiteral *IntLiteral = dyn_cast<IntegerLiteral>(LHSExpr);
649 const Expr *BoolExpr = RHSExpr;
650 bool IntFirst = true;
652 IntLiteral = dyn_cast<IntegerLiteral>(RHSExpr);
657 if (!IntLiteral || !BoolExpr->isKnownToHaveBooleanValue())
660 llvm::APInt IntValue = IntLiteral->getValue();
661 if ((IntValue == 1) || (IntValue == 0))
664 bool IntLarger = IntLiteral->getType()->isUnsignedIntegerType() ||
665 !IntValue.isNegative();
667 BinaryOperatorKind Bok = B->getOpcode();
668 if (Bok == BO_GT || Bok == BO_GE) {
669 // Always true for 10 > bool and bool > -1
670 // Always false for -1 > bool and bool > 10
671 return TryResult(IntFirst == IntLarger);
673 // Always true for -1 < bool and bool < 10
674 // Always false for 10 < bool and bool < -1
675 return TryResult(IntFirst != IntLarger);
679 /// Find an incorrect equality comparison. Either with an expression
680 /// evaluating to a boolean and a constant other than 0 and 1.
681 /// e.g. if (!x == 10) or a bitwise and/or operation that always evaluates to
682 /// true/false e.q. (x & 8) == 4.
683 TryResult checkIncorrectEqualityOperator(const BinaryOperator *B) {
684 const Expr *LHSExpr = B->getLHS()->IgnoreParens();
685 const Expr *RHSExpr = B->getRHS()->IgnoreParens();
687 const IntegerLiteral *IntLiteral = dyn_cast<IntegerLiteral>(LHSExpr);
688 const Expr *BoolExpr = RHSExpr;
691 IntLiteral = dyn_cast<IntegerLiteral>(RHSExpr);
698 const BinaryOperator *BitOp = dyn_cast<BinaryOperator>(BoolExpr);
699 if (BitOp && (BitOp->getOpcode() == BO_And ||
700 BitOp->getOpcode() == BO_Or)) {
701 const Expr *LHSExpr2 = BitOp->getLHS()->IgnoreParens();
702 const Expr *RHSExpr2 = BitOp->getRHS()->IgnoreParens();
704 const IntegerLiteral *IntLiteral2 = dyn_cast<IntegerLiteral>(LHSExpr2);
707 IntLiteral2 = dyn_cast<IntegerLiteral>(RHSExpr2);
712 llvm::APInt L1 = IntLiteral->getValue();
713 llvm::APInt L2 = IntLiteral2->getValue();
714 if ((BitOp->getOpcode() == BO_And && (L2 & L1) != L1) ||
715 (BitOp->getOpcode() == BO_Or && (L2 | L1) != L1)) {
716 if (BuildOpts.Observer)
717 BuildOpts.Observer->compareBitwiseEquality(B,
718 B->getOpcode() != BO_EQ);
719 TryResult(B->getOpcode() != BO_EQ);
721 } else if (BoolExpr->isKnownToHaveBooleanValue()) {
722 llvm::APInt IntValue = IntLiteral->getValue();
723 if ((IntValue == 1) || (IntValue == 0)) {
726 return TryResult(B->getOpcode() != BO_EQ);
732 TryResult analyzeLogicOperatorCondition(BinaryOperatorKind Relation,
733 const llvm::APSInt &Value1,
734 const llvm::APSInt &Value2) {
735 assert(Value1.isSigned() == Value2.isSigned());
740 return TryResult(Value1 == Value2);
742 return TryResult(Value1 != Value2);
744 return TryResult(Value1 < Value2);
746 return TryResult(Value1 <= Value2);
748 return TryResult(Value1 > Value2);
750 return TryResult(Value1 >= Value2);
754 /// \brief Find a pair of comparison expressions with or without parentheses
755 /// with a shared variable and constants and a logical operator between them
756 /// that always evaluates to either true or false.
757 /// e.g. if (x != 3 || x != 4)
758 TryResult checkIncorrectLogicOperator(const BinaryOperator *B) {
759 assert(B->isLogicalOp());
760 const BinaryOperator *LHS =
761 dyn_cast<BinaryOperator>(B->getLHS()->IgnoreParens());
762 const BinaryOperator *RHS =
763 dyn_cast<BinaryOperator>(B->getRHS()->IgnoreParens());
767 if (!LHS->isComparisonOp() || !RHS->isComparisonOp())
770 const DeclRefExpr *Decl1;
772 BinaryOperatorKind BO1;
773 std::tie(Decl1, BO1, Expr1) = tryNormalizeBinaryOperator(LHS);
775 if (!Decl1 || !Expr1)
778 const DeclRefExpr *Decl2;
780 BinaryOperatorKind BO2;
781 std::tie(Decl2, BO2, Expr2) = tryNormalizeBinaryOperator(RHS);
783 if (!Decl2 || !Expr2)
786 // Check that it is the same variable on both sides.
787 if (Decl1->getDecl() != Decl2->getDecl())
790 // Make sure the user's intent is clear (e.g. they're comparing against two
791 // int literals, or two things from the same enum)
792 if (!areExprTypesCompatible(Expr1, Expr2))
797 if (!Expr1->EvaluateAsInt(L1, *Context) ||
798 !Expr2->EvaluateAsInt(L2, *Context))
801 // Can't compare signed with unsigned or with different bit width.
802 if (L1.isSigned() != L2.isSigned() || L1.getBitWidth() != L2.getBitWidth())
805 // Values that will be used to determine if result of logical
806 // operator is always true/false
807 const llvm::APSInt Values[] = {
808 // Value less than both Value1 and Value2
809 llvm::APSInt::getMinValue(L1.getBitWidth(), L1.isUnsigned()),
812 // Value between Value1 and Value2
813 ((L1 < L2) ? L1 : L2) + llvm::APSInt(llvm::APInt(L1.getBitWidth(), 1),
817 // Value greater than both Value1 and Value2
818 llvm::APSInt::getMaxValue(L1.getBitWidth(), L1.isUnsigned()),
821 // Check whether expression is always true/false by evaluating the following
822 // * variable x is less than the smallest literal.
823 // * variable x is equal to the smallest literal.
824 // * Variable x is between smallest and largest literal.
825 // * Variable x is equal to the largest literal.
826 // * Variable x is greater than largest literal.
827 bool AlwaysTrue = true, AlwaysFalse = true;
828 for (const llvm::APSInt &Value : Values) {
829 TryResult Res1, Res2;
830 Res1 = analyzeLogicOperatorCondition(BO1, Value, L1);
831 Res2 = analyzeLogicOperatorCondition(BO2, Value, L2);
833 if (!Res1.isKnown() || !Res2.isKnown())
836 if (B->getOpcode() == BO_LAnd) {
837 AlwaysTrue &= (Res1.isTrue() && Res2.isTrue());
838 AlwaysFalse &= !(Res1.isTrue() && Res2.isTrue());
840 AlwaysTrue &= (Res1.isTrue() || Res2.isTrue());
841 AlwaysFalse &= !(Res1.isTrue() || Res2.isTrue());
845 if (AlwaysTrue || AlwaysFalse) {
846 if (BuildOpts.Observer)
847 BuildOpts.Observer->compareAlwaysTrue(B, AlwaysTrue);
848 return TryResult(AlwaysTrue);
853 /// Try and evaluate an expression to an integer constant.
854 bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) {
855 if (!BuildOpts.PruneTriviallyFalseEdges)
857 return !S->isTypeDependent() &&
858 !S->isValueDependent() &&
859 S->EvaluateAsRValue(outResult, *Context);
862 /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1
863 /// if we can evaluate to a known value, otherwise return -1.
864 TryResult tryEvaluateBool(Expr *S) {
865 if (!BuildOpts.PruneTriviallyFalseEdges ||
866 S->isTypeDependent() || S->isValueDependent())
869 if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(S)) {
870 if (Bop->isLogicalOp()) {
871 // Check the cache first.
872 CachedBoolEvalsTy::iterator I = CachedBoolEvals.find(S);
873 if (I != CachedBoolEvals.end())
874 return I->second; // already in map;
876 // Retrieve result at first, or the map might be updated.
877 TryResult Result = evaluateAsBooleanConditionNoCache(S);
878 CachedBoolEvals[S] = Result; // update or insert
882 switch (Bop->getOpcode()) {
884 // For 'x & 0' and 'x * 0', we can determine that
885 // the value is always false.
888 // If either operand is zero, we know the value
891 if (Bop->getLHS()->EvaluateAsInt(IntVal, *Context)) {
892 if (!IntVal.getBoolValue()) {
893 return TryResult(false);
896 if (Bop->getRHS()->EvaluateAsInt(IntVal, *Context)) {
897 if (!IntVal.getBoolValue()) {
898 return TryResult(false);
907 return evaluateAsBooleanConditionNoCache(S);
910 /// \brief Evaluate as boolean \param E without using the cache.
911 TryResult evaluateAsBooleanConditionNoCache(Expr *E) {
912 if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(E)) {
913 if (Bop->isLogicalOp()) {
914 TryResult LHS = tryEvaluateBool(Bop->getLHS());
916 // We were able to evaluate the LHS, see if we can get away with not
917 // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
918 if (LHS.isTrue() == (Bop->getOpcode() == BO_LOr))
921 TryResult RHS = tryEvaluateBool(Bop->getRHS());
923 if (Bop->getOpcode() == BO_LOr)
924 return LHS.isTrue() || RHS.isTrue();
926 return LHS.isTrue() && RHS.isTrue();
929 TryResult RHS = tryEvaluateBool(Bop->getRHS());
931 // We can't evaluate the LHS; however, sometimes the result
932 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
933 if (RHS.isTrue() == (Bop->getOpcode() == BO_LOr))
936 TryResult BopRes = checkIncorrectLogicOperator(Bop);
937 if (BopRes.isKnown())
938 return BopRes.isTrue();
943 } else if (Bop->isEqualityOp()) {
944 TryResult BopRes = checkIncorrectEqualityOperator(Bop);
945 if (BopRes.isKnown())
946 return BopRes.isTrue();
947 } else if (Bop->isRelationalOp()) {
948 TryResult BopRes = checkIncorrectRelationalOperator(Bop);
949 if (BopRes.isKnown())
950 return BopRes.isTrue();
955 if (E->EvaluateAsBooleanCondition(Result, *Context))
963 inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder,
964 const Stmt *stmt) const {
965 return builder.alwaysAdd(stmt) || kind == AlwaysAdd;
968 bool CFGBuilder::alwaysAdd(const Stmt *stmt) {
969 bool shouldAdd = BuildOpts.alwaysAdd(stmt);
971 if (!BuildOpts.forcedBlkExprs)
974 if (lastLookup == stmt) {
976 assert(cachedEntry->first == stmt);
984 // Perform the lookup!
985 CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs;
988 // No need to update 'cachedEntry', since it will always be null.
989 assert(!cachedEntry);
993 CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt);
994 if (itr == fb->end()) {
995 cachedEntry = nullptr;
1003 // FIXME: Add support for dependent-sized array types in C++?
1004 // Does it even make sense to build a CFG for an uninstantiated template?
1005 static const VariableArrayType *FindVA(const Type *t) {
1006 while (const ArrayType *vt = dyn_cast<ArrayType>(t)) {
1007 if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt))
1008 if (vat->getSizeExpr())
1011 t = vt->getElementType().getTypePtr();
1017 /// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an
1018 /// arbitrary statement. Examples include a single expression or a function
1019 /// body (compound statement). The ownership of the returned CFG is
1020 /// transferred to the caller. If CFG construction fails, this method returns
1022 std::unique_ptr<CFG> CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) {
1027 // Create an empty block that will serve as the exit block for the CFG. Since
1028 // this is the first block added to the CFG, it will be implicitly registered
1029 // as the exit block.
1030 Succ = createBlock();
1031 assert(Succ == &cfg->getExit());
1032 Block = nullptr; // the EXIT block is empty. Create all other blocks lazily.
1034 if (BuildOpts.AddImplicitDtors)
1035 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D))
1036 addImplicitDtorsForDestructor(DD);
1038 // Visit the statements and create the CFG.
1039 CFGBlock *B = addStmt(Statement);
1044 // For C++ constructor add initializers to CFG.
1045 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) {
1046 for (auto *I : llvm::reverse(CD->inits())) {
1047 B = addInitializer(I);
1056 // Backpatch the gotos whose label -> block mappings we didn't know when we
1057 // encountered them.
1058 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(),
1059 E = BackpatchBlocks.end(); I != E; ++I ) {
1061 CFGBlock *B = I->block;
1062 const GotoStmt *G = cast<GotoStmt>(B->getTerminator());
1063 LabelMapTy::iterator LI = LabelMap.find(G->getLabel());
1065 // If there is no target for the goto, then we are looking at an
1066 // incomplete AST. Handle this by not registering a successor.
1067 if (LI == LabelMap.end()) continue;
1069 JumpTarget JT = LI->second;
1070 prependAutomaticObjDtorsWithTerminator(B, I->scopePosition,
1072 addSuccessor(B, JT.block);
1075 // Add successors to the Indirect Goto Dispatch block (if we have one).
1076 if (CFGBlock *B = cfg->getIndirectGotoBlock())
1077 for (LabelSetTy::iterator I = AddressTakenLabels.begin(),
1078 E = AddressTakenLabels.end(); I != E; ++I ) {
1080 // Lookup the target block.
1081 LabelMapTy::iterator LI = LabelMap.find(*I);
1083 // If there is no target block that contains label, then we are looking
1084 // at an incomplete AST. Handle this by not registering a successor.
1085 if (LI == LabelMap.end()) continue;
1087 addSuccessor(B, LI->second.block);
1090 // Create an empty entry block that has no predecessors.
1091 cfg->setEntry(createBlock());
1093 return std::move(cfg);
1096 /// createBlock - Used to lazily create blocks that are connected
1097 /// to the current (global) succcessor.
1098 CFGBlock *CFGBuilder::createBlock(bool add_successor) {
1099 CFGBlock *B = cfg->createBlock();
1100 if (add_successor && Succ)
1101 addSuccessor(B, Succ);
1105 /// createNoReturnBlock - Used to create a block is a 'noreturn' point in the
1106 /// CFG. It is *not* connected to the current (global) successor, and instead
1107 /// directly tied to the exit block in order to be reachable.
1108 CFGBlock *CFGBuilder::createNoReturnBlock() {
1109 CFGBlock *B = createBlock(false);
1110 B->setHasNoReturnElement();
1111 addSuccessor(B, &cfg->getExit(), Succ);
1115 /// addInitializer - Add C++ base or member initializer element to CFG.
1116 CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) {
1117 if (!BuildOpts.AddInitializers)
1120 bool HasTemporaries = false;
1122 // Destructors of temporaries in initialization expression should be called
1123 // after initialization finishes.
1124 Expr *Init = I->getInit();
1126 HasTemporaries = isa<ExprWithCleanups>(Init);
1128 if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
1129 // Generate destructors for temporaries in initialization expression.
1130 TempDtorContext Context;
1131 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
1132 /*BindToTemporary=*/false, Context);
1137 appendInitializer(Block, I);
1140 if (HasTemporaries) {
1141 // For expression with temporaries go directly to subexpression to omit
1142 // generating destructors for the second time.
1143 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr());
1145 if (BuildOpts.AddCXXDefaultInitExprInCtors) {
1146 if (CXXDefaultInitExpr *Default = dyn_cast<CXXDefaultInitExpr>(Init)) {
1147 // In general, appending the expression wrapped by a CXXDefaultInitExpr
1148 // may cause the same Expr to appear more than once in the CFG. Doing it
1149 // here is safe because there's only one initializer per field.
1151 appendStmt(Block, Default);
1152 if (Stmt *Child = Default->getExpr())
1153 if (CFGBlock *R = Visit(Child))
1164 /// \brief Retrieve the type of the temporary object whose lifetime was
1165 /// extended by a local reference with the given initializer.
1166 static QualType getReferenceInitTemporaryType(ASTContext &Context,
1168 bool *FoundMTE = nullptr) {
1170 // Skip parentheses.
1171 Init = Init->IgnoreParens();
1173 // Skip through cleanups.
1174 if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Init)) {
1175 Init = EWC->getSubExpr();
1179 // Skip through the temporary-materialization expression.
1180 if (const MaterializeTemporaryExpr *MTE
1181 = dyn_cast<MaterializeTemporaryExpr>(Init)) {
1182 Init = MTE->GetTemporaryExpr();
1188 // Skip derived-to-base and no-op casts.
1189 if (const CastExpr *CE = dyn_cast<CastExpr>(Init)) {
1190 if ((CE->getCastKind() == CK_DerivedToBase ||
1191 CE->getCastKind() == CK_UncheckedDerivedToBase ||
1192 CE->getCastKind() == CK_NoOp) &&
1193 Init->getType()->isRecordType()) {
1194 Init = CE->getSubExpr();
1199 // Skip member accesses into rvalues.
1200 if (const MemberExpr *ME = dyn_cast<MemberExpr>(Init)) {
1201 if (!ME->isArrow() && ME->getBase()->isRValue()) {
1202 Init = ME->getBase();
1210 return Init->getType();
1213 /// addAutomaticObjDtors - Add to current block automatic objects destructors
1214 /// for objects in range of local scope positions. Use S as trigger statement
1215 /// for destructors.
1216 void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B,
1217 LocalScope::const_iterator E, Stmt *S) {
1218 if (!BuildOpts.AddImplicitDtors)
1224 // We need to append the destructors in reverse order, but any one of them
1225 // may be a no-return destructor which changes the CFG. As a result, buffer
1226 // this sequence up and replay them in reverse order when appending onto the
1228 SmallVector<VarDecl*, 10> Decls;
1229 Decls.reserve(B.distance(E));
1230 for (LocalScope::const_iterator I = B; I != E; ++I)
1231 Decls.push_back(*I);
1233 for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(),
1236 // If this destructor is marked as a no-return destructor, we need to
1237 // create a new block for the destructor which does not have as a successor
1238 // anything built thus far: control won't flow out of this block.
1239 QualType Ty = (*I)->getType();
1240 if (Ty->isReferenceType()) {
1241 Ty = getReferenceInitTemporaryType(*Context, (*I)->getInit());
1243 Ty = Context->getBaseElementType(Ty);
1245 if (Ty->getAsCXXRecordDecl()->isAnyDestructorNoReturn())
1246 Block = createNoReturnBlock();
1250 appendAutomaticObjDtor(Block, *I, S);
1254 /// addImplicitDtorsForDestructor - Add implicit destructors generated for
1255 /// base and member objects in destructor.
1256 void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) {
1257 assert (BuildOpts.AddImplicitDtors
1258 && "Can be called only when dtors should be added");
1259 const CXXRecordDecl *RD = DD->getParent();
1261 // At the end destroy virtual base objects.
1262 for (const auto &VI : RD->vbases()) {
1263 const CXXRecordDecl *CD = VI.getType()->getAsCXXRecordDecl();
1264 if (!CD->hasTrivialDestructor()) {
1266 appendBaseDtor(Block, &VI);
1270 // Before virtual bases destroy direct base objects.
1271 for (const auto &BI : RD->bases()) {
1272 if (!BI.isVirtual()) {
1273 const CXXRecordDecl *CD = BI.getType()->getAsCXXRecordDecl();
1274 if (!CD->hasTrivialDestructor()) {
1276 appendBaseDtor(Block, &BI);
1281 // First destroy member objects.
1282 for (auto *FI : RD->fields()) {
1283 // Check for constant size array. Set type to array element type.
1284 QualType QT = FI->getType();
1285 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
1286 if (AT->getSize() == 0)
1288 QT = AT->getElementType();
1291 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
1292 if (!CD->hasTrivialDestructor()) {
1294 appendMemberDtor(Block, FI);
1299 /// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either
1300 /// way return valid LocalScope object.
1301 LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) {
1304 llvm::BumpPtrAllocator &alloc = cfg->getAllocator();
1305 return new (alloc.Allocate<LocalScope>())
1306 LocalScope(BumpVectorContext(alloc), ScopePos);
1309 /// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement
1310 /// that should create implicit scope (e.g. if/else substatements).
1311 void CFGBuilder::addLocalScopeForStmt(Stmt *S) {
1312 if (!BuildOpts.AddImplicitDtors)
1315 LocalScope *Scope = nullptr;
1317 // For compound statement we will be creating explicit scope.
1318 if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
1319 for (auto *BI : CS->body()) {
1320 Stmt *SI = BI->stripLabelLikeStatements();
1321 if (DeclStmt *DS = dyn_cast<DeclStmt>(SI))
1322 Scope = addLocalScopeForDeclStmt(DS, Scope);
1327 // For any other statement scope will be implicit and as such will be
1328 // interesting only for DeclStmt.
1329 if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements()))
1330 addLocalScopeForDeclStmt(DS);
1333 /// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will
1334 /// reuse Scope if not NULL.
1335 LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS,
1336 LocalScope* Scope) {
1337 if (!BuildOpts.AddImplicitDtors)
1340 for (auto *DI : DS->decls())
1341 if (VarDecl *VD = dyn_cast<VarDecl>(DI))
1342 Scope = addLocalScopeForVarDecl(VD, Scope);
1346 /// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will
1347 /// create add scope for automatic objects and temporary objects bound to
1348 /// const reference. Will reuse Scope if not NULL.
1349 LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD,
1350 LocalScope* Scope) {
1351 if (!BuildOpts.AddImplicitDtors)
1354 // Check if variable is local.
1355 switch (VD->getStorageClass()) {
1360 default: return Scope;
1363 // Check for const references bound to temporary. Set type to pointee.
1364 QualType QT = VD->getType();
1365 if (QT.getTypePtr()->isReferenceType()) {
1366 // Attempt to determine whether this declaration lifetime-extends a
1369 // FIXME: This is incorrect. Non-reference declarations can lifetime-extend
1370 // temporaries, and a single declaration can extend multiple temporaries.
1371 // We should look at the storage duration on each nested
1372 // MaterializeTemporaryExpr instead.
1373 const Expr *Init = VD->getInit();
1377 // Lifetime-extending a temporary.
1378 bool FoundMTE = false;
1379 QT = getReferenceInitTemporaryType(*Context, Init, &FoundMTE);
1384 // Check for constant size array. Set type to array element type.
1385 while (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
1386 if (AT->getSize() == 0)
1388 QT = AT->getElementType();
1391 // Check if type is a C++ class with non-trivial destructor.
1392 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
1393 if (CD->hasDefinition() && !CD->hasTrivialDestructor()) {
1394 // Add the variable to scope
1395 Scope = createOrReuseLocalScope(Scope);
1397 ScopePos = Scope->begin();
1402 /// addLocalScopeAndDtors - For given statement add local scope for it and
1403 /// add destructors that will cleanup the scope. Will reuse Scope if not NULL.
1404 void CFGBuilder::addLocalScopeAndDtors(Stmt *S) {
1405 if (!BuildOpts.AddImplicitDtors)
1408 LocalScope::const_iterator scopeBeginPos = ScopePos;
1409 addLocalScopeForStmt(S);
1410 addAutomaticObjDtors(ScopePos, scopeBeginPos, S);
1413 /// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for
1414 /// variables with automatic storage duration to CFGBlock's elements vector.
1415 /// Elements will be prepended to physical beginning of the vector which
1416 /// happens to be logical end. Use blocks terminator as statement that specifies
1417 /// destructors call site.
1418 /// FIXME: This mechanism for adding automatic destructors doesn't handle
1419 /// no-return destructors properly.
1420 void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
1421 LocalScope::const_iterator B, LocalScope::const_iterator E) {
1422 BumpVectorContext &C = cfg->getBumpVectorContext();
1423 CFGBlock::iterator InsertPos
1424 = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C);
1425 for (LocalScope::const_iterator I = B; I != E; ++I)
1426 InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I,
1427 Blk->getTerminator());
1430 /// Visit - Walk the subtree of a statement and add extra
1431 /// blocks for ternary operators, &&, and ||. We also process "," and
1432 /// DeclStmts (which may contain nested control-flow).
1433 CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) {
1439 if (Expr *E = dyn_cast<Expr>(S))
1440 S = E->IgnoreParens();
1442 switch (S->getStmtClass()) {
1444 return VisitStmt(S, asc);
1446 case Stmt::AddrLabelExprClass:
1447 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc);
1449 case Stmt::BinaryConditionalOperatorClass:
1450 return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc);
1452 case Stmt::BinaryOperatorClass:
1453 return VisitBinaryOperator(cast<BinaryOperator>(S), asc);
1455 case Stmt::BlockExprClass:
1456 return VisitBlockExpr(cast<BlockExpr>(S), asc);
1458 case Stmt::BreakStmtClass:
1459 return VisitBreakStmt(cast<BreakStmt>(S));
1461 case Stmt::CallExprClass:
1462 case Stmt::CXXOperatorCallExprClass:
1463 case Stmt::CXXMemberCallExprClass:
1464 case Stmt::UserDefinedLiteralClass:
1465 return VisitCallExpr(cast<CallExpr>(S), asc);
1467 case Stmt::CaseStmtClass:
1468 return VisitCaseStmt(cast<CaseStmt>(S));
1470 case Stmt::ChooseExprClass:
1471 return VisitChooseExpr(cast<ChooseExpr>(S), asc);
1473 case Stmt::CompoundStmtClass:
1474 return VisitCompoundStmt(cast<CompoundStmt>(S));
1476 case Stmt::ConditionalOperatorClass:
1477 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc);
1479 case Stmt::ContinueStmtClass:
1480 return VisitContinueStmt(cast<ContinueStmt>(S));
1482 case Stmt::CXXCatchStmtClass:
1483 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S));
1485 case Stmt::ExprWithCleanupsClass:
1486 return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc);
1488 case Stmt::CXXDefaultArgExprClass:
1489 case Stmt::CXXDefaultInitExprClass:
1490 // FIXME: The expression inside a CXXDefaultArgExpr is owned by the
1491 // called function's declaration, not by the caller. If we simply add
1492 // this expression to the CFG, we could end up with the same Expr
1493 // appearing multiple times.
1494 // PR13385 / <rdar://problem/12156507>
1496 // It's likewise possible for multiple CXXDefaultInitExprs for the same
1497 // expression to be used in the same function (through aggregate
1499 return VisitStmt(S, asc);
1501 case Stmt::CXXBindTemporaryExprClass:
1502 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc);
1504 case Stmt::CXXConstructExprClass:
1505 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc);
1507 case Stmt::CXXNewExprClass:
1508 return VisitCXXNewExpr(cast<CXXNewExpr>(S), asc);
1510 case Stmt::CXXDeleteExprClass:
1511 return VisitCXXDeleteExpr(cast<CXXDeleteExpr>(S), asc);
1513 case Stmt::CXXFunctionalCastExprClass:
1514 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc);
1516 case Stmt::CXXTemporaryObjectExprClass:
1517 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc);
1519 case Stmt::CXXThrowExprClass:
1520 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S));
1522 case Stmt::CXXTryStmtClass:
1523 return VisitCXXTryStmt(cast<CXXTryStmt>(S));
1525 case Stmt::CXXForRangeStmtClass:
1526 return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S));
1528 case Stmt::DeclStmtClass:
1529 return VisitDeclStmt(cast<DeclStmt>(S));
1531 case Stmt::DefaultStmtClass:
1532 return VisitDefaultStmt(cast<DefaultStmt>(S));
1534 case Stmt::DoStmtClass:
1535 return VisitDoStmt(cast<DoStmt>(S));
1537 case Stmt::ForStmtClass:
1538 return VisitForStmt(cast<ForStmt>(S));
1540 case Stmt::GotoStmtClass:
1541 return VisitGotoStmt(cast<GotoStmt>(S));
1543 case Stmt::IfStmtClass:
1544 return VisitIfStmt(cast<IfStmt>(S));
1546 case Stmt::ImplicitCastExprClass:
1547 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc);
1549 case Stmt::IndirectGotoStmtClass:
1550 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S));
1552 case Stmt::LabelStmtClass:
1553 return VisitLabelStmt(cast<LabelStmt>(S));
1555 case Stmt::LambdaExprClass:
1556 return VisitLambdaExpr(cast<LambdaExpr>(S), asc);
1558 case Stmt::MemberExprClass:
1559 return VisitMemberExpr(cast<MemberExpr>(S), asc);
1561 case Stmt::NullStmtClass:
1564 case Stmt::ObjCAtCatchStmtClass:
1565 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S));
1567 case Stmt::ObjCAutoreleasePoolStmtClass:
1568 return VisitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(S));
1570 case Stmt::ObjCAtSynchronizedStmtClass:
1571 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S));
1573 case Stmt::ObjCAtThrowStmtClass:
1574 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S));
1576 case Stmt::ObjCAtTryStmtClass:
1577 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S));
1579 case Stmt::ObjCForCollectionStmtClass:
1580 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S));
1582 case Stmt::OpaqueValueExprClass:
1585 case Stmt::PseudoObjectExprClass:
1586 return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S));
1588 case Stmt::ReturnStmtClass:
1589 return VisitReturnStmt(cast<ReturnStmt>(S));
1591 case Stmt::UnaryExprOrTypeTraitExprClass:
1592 return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S),
1595 case Stmt::StmtExprClass:
1596 return VisitStmtExpr(cast<StmtExpr>(S), asc);
1598 case Stmt::SwitchStmtClass:
1599 return VisitSwitchStmt(cast<SwitchStmt>(S));
1601 case Stmt::UnaryOperatorClass:
1602 return VisitUnaryOperator(cast<UnaryOperator>(S), asc);
1604 case Stmt::WhileStmtClass:
1605 return VisitWhileStmt(cast<WhileStmt>(S));
1609 CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) {
1610 if (asc.alwaysAdd(*this, S)) {
1612 appendStmt(Block, S);
1615 return VisitChildren(S);
1618 /// VisitChildren - Visit the children of a Stmt.
1619 CFGBlock *CFGBuilder::VisitChildren(Stmt *S) {
1620 CFGBlock *B = Block;
1622 // Visit the children in their reverse order so that they appear in
1623 // left-to-right (natural) order in the CFG.
1624 reverse_children RChildren(S);
1625 for (reverse_children::iterator I = RChildren.begin(), E = RChildren.end();
1627 if (Stmt *Child = *I)
1628 if (CFGBlock *R = Visit(Child))
1634 CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A,
1635 AddStmtChoice asc) {
1636 AddressTakenLabels.insert(A->getLabel());
1638 if (asc.alwaysAdd(*this, A)) {
1640 appendStmt(Block, A);
1646 CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U,
1647 AddStmtChoice asc) {
1648 if (asc.alwaysAdd(*this, U)) {
1650 appendStmt(Block, U);
1653 return Visit(U->getSubExpr(), AddStmtChoice());
1656 CFGBlock *CFGBuilder::VisitLogicalOperator(BinaryOperator *B) {
1657 CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
1658 appendStmt(ConfluenceBlock, B);
1663 return VisitLogicalOperator(B, nullptr, ConfluenceBlock,
1664 ConfluenceBlock).first;
1667 std::pair<CFGBlock*, CFGBlock*>
1668 CFGBuilder::VisitLogicalOperator(BinaryOperator *B,
1670 CFGBlock *TrueBlock,
1671 CFGBlock *FalseBlock) {
1673 // Introspect the RHS. If it is a nested logical operation, we recursively
1674 // build the CFG using this function. Otherwise, resort to default
1675 // CFG construction behavior.
1676 Expr *RHS = B->getRHS()->IgnoreParens();
1677 CFGBlock *RHSBlock, *ExitBlock;
1680 if (BinaryOperator *B_RHS = dyn_cast<BinaryOperator>(RHS))
1681 if (B_RHS->isLogicalOp()) {
1682 std::tie(RHSBlock, ExitBlock) =
1683 VisitLogicalOperator(B_RHS, Term, TrueBlock, FalseBlock);
1687 // The RHS is not a nested logical operation. Don't push the terminator
1688 // down further, but instead visit RHS and construct the respective
1689 // pieces of the CFG, and link up the RHSBlock with the terminator
1690 // we have been provided.
1691 ExitBlock = RHSBlock = createBlock(false);
1693 // Even though KnownVal is only used in the else branch of the next
1694 // conditional, tryEvaluateBool performs additional checking on the
1695 // Expr, so it should be called unconditionally.
1696 TryResult KnownVal = tryEvaluateBool(RHS);
1697 if (!KnownVal.isKnown())
1698 KnownVal = tryEvaluateBool(B);
1701 assert(TrueBlock == FalseBlock);
1702 addSuccessor(RHSBlock, TrueBlock);
1705 RHSBlock->setTerminator(Term);
1706 addSuccessor(RHSBlock, TrueBlock, !KnownVal.isFalse());
1707 addSuccessor(RHSBlock, FalseBlock, !KnownVal.isTrue());
1711 RHSBlock = addStmt(RHS);
1716 return std::make_pair(nullptr, nullptr);
1718 // Generate the blocks for evaluating the LHS.
1719 Expr *LHS = B->getLHS()->IgnoreParens();
1721 if (BinaryOperator *B_LHS = dyn_cast<BinaryOperator>(LHS))
1722 if (B_LHS->isLogicalOp()) {
1723 if (B->getOpcode() == BO_LOr)
1724 FalseBlock = RHSBlock;
1726 TrueBlock = RHSBlock;
1728 // For the LHS, treat 'B' as the terminator that we want to sink
1729 // into the nested branch. The RHS always gets the top-most
1731 return VisitLogicalOperator(B_LHS, B, TrueBlock, FalseBlock);
1734 // Create the block evaluating the LHS.
1735 // This contains the '&&' or '||' as the terminator.
1736 CFGBlock *LHSBlock = createBlock(false);
1737 LHSBlock->setTerminator(B);
1740 CFGBlock *EntryLHSBlock = addStmt(LHS);
1743 return std::make_pair(nullptr, nullptr);
1745 // See if this is a known constant.
1746 TryResult KnownVal = tryEvaluateBool(LHS);
1748 // Now link the LHSBlock with RHSBlock.
1749 if (B->getOpcode() == BO_LOr) {
1750 addSuccessor(LHSBlock, TrueBlock, !KnownVal.isFalse());
1751 addSuccessor(LHSBlock, RHSBlock, !KnownVal.isTrue());
1753 assert(B->getOpcode() == BO_LAnd);
1754 addSuccessor(LHSBlock, RHSBlock, !KnownVal.isFalse());
1755 addSuccessor(LHSBlock, FalseBlock, !KnownVal.isTrue());
1758 return std::make_pair(EntryLHSBlock, ExitBlock);
1762 CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B,
1763 AddStmtChoice asc) {
1765 if (B->isLogicalOp())
1766 return VisitLogicalOperator(B);
1768 if (B->getOpcode() == BO_Comma) { // ,
1770 appendStmt(Block, B);
1771 addStmt(B->getRHS());
1772 return addStmt(B->getLHS());
1775 if (B->isAssignmentOp()) {
1776 if (asc.alwaysAdd(*this, B)) {
1778 appendStmt(Block, B);
1781 return Visit(B->getRHS());
1784 if (asc.alwaysAdd(*this, B)) {
1786 appendStmt(Block, B);
1789 CFGBlock *RBlock = Visit(B->getRHS());
1790 CFGBlock *LBlock = Visit(B->getLHS());
1791 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr
1792 // containing a DoStmt, and the LHS doesn't create a new block, then we should
1793 // return RBlock. Otherwise we'll incorrectly return NULL.
1794 return (LBlock ? LBlock : RBlock);
1797 CFGBlock *CFGBuilder::VisitNoRecurse(Expr *E, AddStmtChoice asc) {
1798 if (asc.alwaysAdd(*this, E)) {
1800 appendStmt(Block, E);
1805 CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) {
1806 // "break" is a control-flow statement. Thus we stop processing the current
1811 // Now create a new block that ends with the break statement.
1812 Block = createBlock(false);
1813 Block->setTerminator(B);
1815 // If there is no target for the break, then we are looking at an incomplete
1816 // AST. This means that the CFG cannot be constructed.
1817 if (BreakJumpTarget.block) {
1818 addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B);
1819 addSuccessor(Block, BreakJumpTarget.block);
1827 static bool CanThrow(Expr *E, ASTContext &Ctx) {
1828 QualType Ty = E->getType();
1829 if (Ty->isFunctionPointerType())
1830 Ty = Ty->getAs<PointerType>()->getPointeeType();
1831 else if (Ty->isBlockPointerType())
1832 Ty = Ty->getAs<BlockPointerType>()->getPointeeType();
1834 const FunctionType *FT = Ty->getAs<FunctionType>();
1836 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT))
1837 if (!isUnresolvedExceptionSpec(Proto->getExceptionSpecType()) &&
1838 Proto->isNothrow(Ctx))
1844 CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) {
1845 // Compute the callee type.
1846 QualType calleeType = C->getCallee()->getType();
1847 if (calleeType == Context->BoundMemberTy) {
1848 QualType boundType = Expr::findBoundMemberType(C->getCallee());
1850 // We should only get a null bound type if processing a dependent
1851 // CFG. Recover by assuming nothing.
1852 if (!boundType.isNull()) calleeType = boundType;
1855 // If this is a call to a no-return function, this stops the block here.
1856 bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn();
1858 bool AddEHEdge = false;
1860 // Languages without exceptions are assumed to not throw.
1861 if (Context->getLangOpts().Exceptions) {
1862 if (BuildOpts.AddEHEdges)
1866 // If this is a call to a builtin function, it might not actually evaluate
1867 // its arguments. Don't add them to the CFG if this is the case.
1868 bool OmitArguments = false;
1870 if (FunctionDecl *FD = C->getDirectCallee()) {
1871 if (FD->isNoReturn())
1873 if (FD->hasAttr<NoThrowAttr>())
1875 if (FD->getBuiltinID() == Builtin::BI__builtin_object_size)
1876 OmitArguments = true;
1879 if (!CanThrow(C->getCallee(), *Context))
1882 if (OmitArguments) {
1883 assert(!NoReturn && "noreturn calls with unevaluated args not implemented");
1884 assert(!AddEHEdge && "EH calls with unevaluated args not implemented");
1886 appendStmt(Block, C);
1887 return Visit(C->getCallee());
1890 if (!NoReturn && !AddEHEdge) {
1891 return VisitStmt(C, asc.withAlwaysAdd(true));
1901 Block = createNoReturnBlock();
1903 Block = createBlock();
1905 appendStmt(Block, C);
1908 // Add exceptional edges.
1909 if (TryTerminatedBlock)
1910 addSuccessor(Block, TryTerminatedBlock);
1912 addSuccessor(Block, &cfg->getExit());
1915 return VisitChildren(C);
1918 CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C,
1919 AddStmtChoice asc) {
1920 CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
1921 appendStmt(ConfluenceBlock, C);
1925 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
1926 Succ = ConfluenceBlock;
1928 CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd);
1932 Succ = ConfluenceBlock;
1934 CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd);
1938 Block = createBlock(false);
1939 // See if this is a known constant.
1940 const TryResult& KnownVal = tryEvaluateBool(C->getCond());
1941 addSuccessor(Block, KnownVal.isFalse() ? nullptr : LHSBlock);
1942 addSuccessor(Block, KnownVal.isTrue() ? nullptr : RHSBlock);
1943 Block->setTerminator(C);
1944 return addStmt(C->getCond());
1948 CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) {
1949 LocalScope::const_iterator scopeBeginPos = ScopePos;
1950 if (BuildOpts.AddImplicitDtors) {
1951 addLocalScopeForStmt(C);
1953 if (!C->body_empty() && !isa<ReturnStmt>(*C->body_rbegin())) {
1954 // If the body ends with a ReturnStmt, the dtors will be added in
1956 addAutomaticObjDtors(ScopePos, scopeBeginPos, C);
1959 CFGBlock *LastBlock = Block;
1961 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend();
1963 // If we hit a segment of code just containing ';' (NullStmts), we can
1964 // get a null block back. In such cases, just use the LastBlock
1965 if (CFGBlock *newBlock = addStmt(*I))
1966 LastBlock = newBlock;
1975 CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C,
1976 AddStmtChoice asc) {
1977 const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C);
1978 const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : nullptr);
1980 // Create the confluence block that will "merge" the results of the ternary
1982 CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
1983 appendStmt(ConfluenceBlock, C);
1987 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
1989 // Create a block for the LHS expression if there is an LHS expression. A
1990 // GCC extension allows LHS to be NULL, causing the condition to be the
1991 // value that is returned instead.
1992 // e.g: x ?: y is shorthand for: x ? x : y;
1993 Succ = ConfluenceBlock;
1995 CFGBlock *LHSBlock = nullptr;
1996 const Expr *trueExpr = C->getTrueExpr();
1997 if (trueExpr != opaqueValue) {
1998 LHSBlock = Visit(C->getTrueExpr(), alwaysAdd);
2004 LHSBlock = ConfluenceBlock;
2006 // Create the block for the RHS expression.
2007 Succ = ConfluenceBlock;
2008 CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd);
2012 // If the condition is a logical '&&' or '||', build a more accurate CFG.
2013 if (BinaryOperator *Cond =
2014 dyn_cast<BinaryOperator>(C->getCond()->IgnoreParens()))
2015 if (Cond->isLogicalOp())
2016 return VisitLogicalOperator(Cond, C, LHSBlock, RHSBlock).first;
2018 // Create the block that will contain the condition.
2019 Block = createBlock(false);
2021 // See if this is a known constant.
2022 const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2023 addSuccessor(Block, LHSBlock, !KnownVal.isFalse());
2024 addSuccessor(Block, RHSBlock, !KnownVal.isTrue());
2025 Block->setTerminator(C);
2026 Expr *condExpr = C->getCond();
2029 // Run the condition expression if it's not trivially expressed in
2030 // terms of the opaque value (or if there is no opaque value).
2031 if (condExpr != opaqueValue)
2034 // Before that, run the common subexpression if there was one.
2035 // At least one of this or the above will be run.
2036 return addStmt(BCO->getCommon());
2039 return addStmt(condExpr);
2042 CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) {
2043 // Check if the Decl is for an __label__. If so, elide it from the
2045 if (isa<LabelDecl>(*DS->decl_begin()))
2048 // This case also handles static_asserts.
2049 if (DS->isSingleDecl())
2050 return VisitDeclSubExpr(DS);
2052 CFGBlock *B = nullptr;
2054 // Build an individual DeclStmt for each decl.
2055 for (DeclStmt::reverse_decl_iterator I = DS->decl_rbegin(),
2056 E = DS->decl_rend();
2058 // Get the alignment of the new DeclStmt, padding out to >=8 bytes.
2059 unsigned A = alignof(DeclStmt) < 8 ? 8 : alignof(DeclStmt);
2061 // Allocate the DeclStmt using the BumpPtrAllocator. It will get
2062 // automatically freed with the CFG.
2063 DeclGroupRef DG(*I);
2065 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A);
2066 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D));
2067 cfg->addSyntheticDeclStmt(DSNew, DS);
2069 // Append the fake DeclStmt to block.
2070 B = VisitDeclSubExpr(DSNew);
2076 /// VisitDeclSubExpr - Utility method to add block-level expressions for
2077 /// DeclStmts and initializers in them.
2078 CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) {
2079 assert(DS->isSingleDecl() && "Can handle single declarations only.");
2080 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl());
2083 // Of everything that can be declared in a DeclStmt, only VarDecls impact
2084 // runtime semantics.
2088 bool HasTemporaries = false;
2090 // Guard static initializers under a branch.
2091 CFGBlock *blockAfterStaticInit = nullptr;
2093 if (BuildOpts.AddStaticInitBranches && VD->isStaticLocal()) {
2094 // For static variables, we need to create a branch to track
2095 // whether or not they are initialized.
2102 blockAfterStaticInit = Succ;
2105 // Destructors of temporaries in initialization expression should be called
2106 // after initialization finishes.
2107 Expr *Init = VD->getInit();
2109 HasTemporaries = isa<ExprWithCleanups>(Init);
2111 if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
2112 // Generate destructors for temporaries in initialization expression.
2113 TempDtorContext Context;
2114 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
2115 /*BindToTemporary=*/false, Context);
2120 appendStmt(Block, DS);
2122 // Keep track of the last non-null block, as 'Block' can be nulled out
2123 // if the initializer expression is something like a 'while' in a
2124 // statement-expression.
2125 CFGBlock *LastBlock = Block;
2128 if (HasTemporaries) {
2129 // For expression with temporaries go directly to subexpression to omit
2130 // generating destructors for the second time.
2131 ExprWithCleanups *EC = cast<ExprWithCleanups>(Init);
2132 if (CFGBlock *newBlock = Visit(EC->getSubExpr()))
2133 LastBlock = newBlock;
2136 if (CFGBlock *newBlock = Visit(Init))
2137 LastBlock = newBlock;
2141 // If the type of VD is a VLA, then we must process its size expressions.
2142 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr());
2143 VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr())) {
2144 if (CFGBlock *newBlock = addStmt(VA->getSizeExpr()))
2145 LastBlock = newBlock;
2148 // Remove variable from local scope.
2149 if (ScopePos && VD == *ScopePos)
2152 CFGBlock *B = LastBlock;
2153 if (blockAfterStaticInit) {
2155 Block = createBlock(false);
2156 Block->setTerminator(DS);
2157 addSuccessor(Block, blockAfterStaticInit);
2158 addSuccessor(Block, B);
2165 CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) {
2166 // We may see an if statement in the middle of a basic block, or it may be the
2167 // first statement we are processing. In either case, we create a new basic
2168 // block. First, we create the blocks for the then...else statements, and
2169 // then we create the block containing the if statement. If we were in the
2170 // middle of a block, we stop processing that block. That block is then the
2171 // implicit successor for the "then" and "else" clauses.
2173 // Save local scope position because in case of condition variable ScopePos
2174 // won't be restored when traversing AST.
2175 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2177 // Create local scope for C++17 if init-stmt if one exists.
2178 if (Stmt *Init = I->getInit())
2179 addLocalScopeForStmt(Init);
2181 // Create local scope for possible condition variable.
2182 // Store scope position. Add implicit destructor.
2183 if (VarDecl *VD = I->getConditionVariable())
2184 addLocalScopeForVarDecl(VD);
2186 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), I);
2188 // The block we were processing is now finished. Make it the successor
2196 // Process the false branch.
2197 CFGBlock *ElseBlock = Succ;
2199 if (Stmt *Else = I->getElse()) {
2200 SaveAndRestore<CFGBlock*> sv(Succ);
2202 // NULL out Block so that the recursive call to Visit will
2203 // create a new basic block.
2206 // If branch is not a compound statement create implicit scope
2207 // and add destructors.
2208 if (!isa<CompoundStmt>(Else))
2209 addLocalScopeAndDtors(Else);
2211 ElseBlock = addStmt(Else);
2213 if (!ElseBlock) // Can occur when the Else body has all NullStmts.
2214 ElseBlock = sv.get();
2221 // Process the true branch.
2222 CFGBlock *ThenBlock;
2224 Stmt *Then = I->getThen();
2226 SaveAndRestore<CFGBlock*> sv(Succ);
2229 // If branch is not a compound statement create implicit scope
2230 // and add destructors.
2231 if (!isa<CompoundStmt>(Then))
2232 addLocalScopeAndDtors(Then);
2234 ThenBlock = addStmt(Then);
2237 // We can reach here if the "then" body has all NullStmts.
2238 // Create an empty block so we can distinguish between true and false
2239 // branches in path-sensitive analyses.
2240 ThenBlock = createBlock(false);
2241 addSuccessor(ThenBlock, sv.get());
2248 // Specially handle "if (expr1 || ...)" and "if (expr1 && ...)" by
2249 // having these handle the actual control-flow jump. Note that
2250 // if we introduce a condition variable, e.g. "if (int x = exp1 || exp2)"
2251 // we resort to the old control-flow behavior. This special handling
2252 // removes infeasible paths from the control-flow graph by having the
2253 // control-flow transfer of '&&' or '||' go directly into the then/else
2255 BinaryOperator *Cond =
2256 I->getConditionVariable()
2258 : dyn_cast<BinaryOperator>(I->getCond()->IgnoreParens());
2259 CFGBlock *LastBlock;
2260 if (Cond && Cond->isLogicalOp())
2261 LastBlock = VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first;
2263 // Now create a new block containing the if statement.
2264 Block = createBlock(false);
2266 // Set the terminator of the new block to the If statement.
2267 Block->setTerminator(I);
2269 // See if this is a known constant.
2270 const TryResult &KnownVal = tryEvaluateBool(I->getCond());
2272 // Add the successors. If we know that specific branches are
2273 // unreachable, inform addSuccessor() of that knowledge.
2274 addSuccessor(Block, ThenBlock, /* isReachable = */ !KnownVal.isFalse());
2275 addSuccessor(Block, ElseBlock, /* isReachable = */ !KnownVal.isTrue());
2277 // Add the condition as the last statement in the new block. This may
2278 // create new blocks as the condition may contain control-flow. Any newly
2279 // created blocks will be pointed to be "Block".
2280 LastBlock = addStmt(I->getCond());
2282 // If the IfStmt contains a condition variable, add it and its
2283 // initializer to the CFG.
2284 if (const DeclStmt* DS = I->getConditionVariableDeclStmt()) {
2286 LastBlock = addStmt(const_cast<DeclStmt *>(DS));
2290 // Finally, if the IfStmt contains a C++17 init-stmt, add it to the CFG.
2291 if (Stmt *Init = I->getInit()) {
2293 LastBlock = addStmt(Init);
2300 CFGBlock *CFGBuilder::VisitReturnStmt(ReturnStmt *R) {
2301 // If we were in the middle of a block we stop processing that block.
2303 // NOTE: If a "return" appears in the middle of a block, this means that the
2304 // code afterwards is DEAD (unreachable). We still keep a basic block
2305 // for that code; a simple "mark-and-sweep" from the entry block will be
2306 // able to report such dead blocks.
2308 // Create the new block.
2309 Block = createBlock(false);
2311 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R);
2313 // If the one of the destructors does not return, we already have the Exit
2314 // block as a successor.
2315 if (!Block->hasNoReturnElement())
2316 addSuccessor(Block, &cfg->getExit());
2318 // Add the return statement to the block. This may create new blocks if R
2319 // contains control-flow (short-circuit operations).
2320 return VisitStmt(R, AddStmtChoice::AlwaysAdd);
2323 CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) {
2324 // Get the block of the labeled statement. Add it to our map.
2325 addStmt(L->getSubStmt());
2326 CFGBlock *LabelBlock = Block;
2328 if (!LabelBlock) // This can happen when the body is empty, i.e.
2329 LabelBlock = createBlock(); // scopes that only contains NullStmts.
2331 assert(LabelMap.find(L->getDecl()) == LabelMap.end() &&
2332 "label already in map");
2333 LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos);
2335 // Labels partition blocks, so this is the end of the basic block we were
2336 // processing (L is the block's label). Because this is label (and we have
2337 // already processed the substatement) there is no extra control-flow to worry
2339 LabelBlock->setLabel(L);
2343 // We set Block to NULL to allow lazy creation of a new block (if necessary);
2346 // This block is now the implicit successor of other blocks.
2352 CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) {
2353 CFGBlock *LastBlock = VisitNoRecurse(E, asc);
2354 for (const BlockDecl::Capture &CI : E->getBlockDecl()->captures()) {
2355 if (Expr *CopyExpr = CI.getCopyExpr()) {
2356 CFGBlock *Tmp = Visit(CopyExpr);
2364 CFGBlock *CFGBuilder::VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc) {
2365 CFGBlock *LastBlock = VisitNoRecurse(E, asc);
2366 for (LambdaExpr::capture_init_iterator it = E->capture_init_begin(),
2367 et = E->capture_init_end(); it != et; ++it) {
2368 if (Expr *Init = *it) {
2369 CFGBlock *Tmp = Visit(Init);
2377 CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) {
2378 // Goto is a control-flow statement. Thus we stop processing the current
2379 // block and create a new one.
2381 Block = createBlock(false);
2382 Block->setTerminator(G);
2384 // If we already know the mapping to the label block add the successor now.
2385 LabelMapTy::iterator I = LabelMap.find(G->getLabel());
2387 if (I == LabelMap.end())
2388 // We will need to backpatch this block later.
2389 BackpatchBlocks.push_back(JumpSource(Block, ScopePos));
2391 JumpTarget JT = I->second;
2392 addAutomaticObjDtors(ScopePos, JT.scopePosition, G);
2393 addSuccessor(Block, JT.block);
2399 CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) {
2400 CFGBlock *LoopSuccessor = nullptr;
2402 // Save local scope position because in case of condition variable ScopePos
2403 // won't be restored when traversing AST.
2404 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2406 // Create local scope for init statement and possible condition variable.
2407 // Add destructor for init statement and condition variable.
2408 // Store scope position for continue statement.
2409 if (Stmt *Init = F->getInit())
2410 addLocalScopeForStmt(Init);
2411 LocalScope::const_iterator LoopBeginScopePos = ScopePos;
2413 if (VarDecl *VD = F->getConditionVariable())
2414 addLocalScopeForVarDecl(VD);
2415 LocalScope::const_iterator ContinueScopePos = ScopePos;
2417 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F);
2419 // "for" is a control-flow statement. Thus we stop processing the current
2424 LoopSuccessor = Block;
2426 LoopSuccessor = Succ;
2428 // Save the current value for the break targets.
2429 // All breaks should go to the code following the loop.
2430 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
2431 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
2433 CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
2435 // Now create the loop body.
2437 assert(F->getBody());
2439 // Save the current values for Block, Succ, continue and break targets.
2440 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
2441 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
2443 // Create an empty block to represent the transition block for looping back
2444 // to the head of the loop. If we have increment code, it will
2445 // go in this block as well.
2446 Block = Succ = TransitionBlock = createBlock(false);
2447 TransitionBlock->setLoopTarget(F);
2449 if (Stmt *I = F->getInc()) {
2450 // Generate increment code in its own basic block. This is the target of
2451 // continue statements.
2455 // Finish up the increment (or empty) block if it hasn't been already.
2457 assert(Block == Succ);
2463 // The starting block for the loop increment is the block that should
2464 // represent the 'loop target' for looping back to the start of the loop.
2465 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
2466 ContinueJumpTarget.block->setLoopTarget(F);
2468 // Loop body should end with destructor of Condition variable (if any).
2469 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F);
2471 // If body is not a compound statement create implicit scope
2472 // and add destructors.
2473 if (!isa<CompoundStmt>(F->getBody()))
2474 addLocalScopeAndDtors(F->getBody());
2476 // Now populate the body block, and in the process create new blocks as we
2477 // walk the body of the loop.
2478 BodyBlock = addStmt(F->getBody());
2481 // In the case of "for (...;...;...);" we can have a null BodyBlock.
2482 // Use the continue jump target as the proxy for the body.
2483 BodyBlock = ContinueJumpTarget.block;
2489 // Because of short-circuit evaluation, the condition of the loop can span
2490 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
2491 // evaluate the condition.
2492 CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
2495 Expr *C = F->getCond();
2497 // Specially handle logical operators, which have a slightly
2498 // more optimal CFG representation.
2499 if (BinaryOperator *Cond =
2500 dyn_cast_or_null<BinaryOperator>(C ? C->IgnoreParens() : nullptr))
2501 if (Cond->isLogicalOp()) {
2502 std::tie(EntryConditionBlock, ExitConditionBlock) =
2503 VisitLogicalOperator(Cond, F, BodyBlock, LoopSuccessor);
2507 // The default case when not handling logical operators.
2508 EntryConditionBlock = ExitConditionBlock = createBlock(false);
2509 ExitConditionBlock->setTerminator(F);
2511 // See if this is a known constant.
2512 TryResult KnownVal(true);
2515 // Now add the actual condition to the condition block.
2516 // Because the condition itself may contain control-flow, new blocks may
2517 // be created. Thus we update "Succ" after adding the condition.
2518 Block = ExitConditionBlock;
2519 EntryConditionBlock = addStmt(C);
2521 // If this block contains a condition variable, add both the condition
2522 // variable and initializer to the CFG.
2523 if (VarDecl *VD = F->getConditionVariable()) {
2524 if (Expr *Init = VD->getInit()) {
2526 appendStmt(Block, F->getConditionVariableDeclStmt());
2527 EntryConditionBlock = addStmt(Init);
2528 assert(Block == EntryConditionBlock);
2532 if (Block && badCFG)
2535 KnownVal = tryEvaluateBool(C);
2538 // Add the loop body entry as a successor to the condition.
2539 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
2540 // Link up the condition block with the code that follows the loop. (the
2542 addSuccessor(ExitConditionBlock,
2543 KnownVal.isTrue() ? nullptr : LoopSuccessor);
2547 // Link up the loop-back block to the entry condition block.
2548 addSuccessor(TransitionBlock, EntryConditionBlock);
2550 // The condition block is the implicit successor for any code above the loop.
2551 Succ = EntryConditionBlock;
2553 // If the loop contains initialization, create a new block for those
2554 // statements. This block can also contain statements that precede the loop.
2555 if (Stmt *I = F->getInit()) {
2556 Block = createBlock();
2560 // There is no loop initialization. We are thus basically a while loop.
2561 // NULL out Block to force lazy block construction.
2563 Succ = EntryConditionBlock;
2564 return EntryConditionBlock;
2567 CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) {
2568 if (asc.alwaysAdd(*this, M)) {
2570 appendStmt(Block, M);
2572 return Visit(M->getBase());
2575 CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) {
2576 // Objective-C fast enumeration 'for' statements:
2577 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC
2579 // for ( Type newVariable in collection_expression ) { statements }
2584 // 1. collection_expression
2585 // T. jump to loop_entry
2587 // 1. side-effects of element expression
2588 // 1. ObjCForCollectionStmt [performs binding to newVariable]
2589 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil]
2592 // T. jump to loop_entry
2598 // Type existingItem;
2599 // for ( existingItem in expression ) { statements }
2603 // the same with newVariable replaced with existingItem; the binding works
2604 // the same except that for one ObjCForCollectionStmt::getElement() returns
2605 // a DeclStmt and the other returns a DeclRefExpr.
2608 CFGBlock *LoopSuccessor = nullptr;
2613 LoopSuccessor = Block;
2616 LoopSuccessor = Succ;
2618 // Build the condition blocks.
2619 CFGBlock *ExitConditionBlock = createBlock(false);
2621 // Set the terminator for the "exit" condition block.
2622 ExitConditionBlock->setTerminator(S);
2624 // The last statement in the block should be the ObjCForCollectionStmt, which
2625 // performs the actual binding to 'element' and determines if there are any
2626 // more items in the collection.
2627 appendStmt(ExitConditionBlock, S);
2628 Block = ExitConditionBlock;
2630 // Walk the 'element' expression to see if there are any side-effects. We
2631 // generate new blocks as necessary. We DON'T add the statement by default to
2632 // the CFG unless it contains control-flow.
2633 CFGBlock *EntryConditionBlock = Visit(S->getElement(),
2634 AddStmtChoice::NotAlwaysAdd);
2641 // The condition block is the implicit successor for the loop body as well as
2642 // any code above the loop.
2643 Succ = EntryConditionBlock;
2645 // Now create the true branch.
2647 // Save the current values for Succ, continue and break targets.
2648 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
2649 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
2650 save_break(BreakJumpTarget);
2652 // Add an intermediate block between the BodyBlock and the
2653 // EntryConditionBlock to represent the "loop back" transition, for looping
2654 // back to the head of the loop.
2655 CFGBlock *LoopBackBlock = nullptr;
2656 Succ = LoopBackBlock = createBlock();
2657 LoopBackBlock->setLoopTarget(S);
2659 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
2660 ContinueJumpTarget = JumpTarget(Succ, ScopePos);
2662 CFGBlock *BodyBlock = addStmt(S->getBody());
2665 BodyBlock = ContinueJumpTarget.block; // can happen for "for (X in Y) ;"
2671 // This new body block is a successor to our "exit" condition block.
2672 addSuccessor(ExitConditionBlock, BodyBlock);
2675 // Link up the condition block with the code that follows the loop.
2676 // (the false branch).
2677 addSuccessor(ExitConditionBlock, LoopSuccessor);
2679 // Now create a prologue block to contain the collection expression.
2680 Block = createBlock();
2681 return addStmt(S->getCollection());
2684 CFGBlock *CFGBuilder::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) {
2686 return addStmt(S->getSubStmt());
2687 // TODO: consider adding cleanups for the end of @autoreleasepool scope.
2690 CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) {
2691 // FIXME: Add locking 'primitives' to CFG for @synchronized.
2694 CFGBlock *SyncBlock = addStmt(S->getSynchBody());
2696 // The sync body starts its own basic block. This makes it a little easier
2697 // for diagnostic clients.
2706 // Add the @synchronized to the CFG.
2708 appendStmt(Block, S);
2710 // Inline the sync expression.
2711 return addStmt(S->getSynchExpr());
2714 CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) {
2719 CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) {
2722 // Add the PseudoObject as the last thing.
2723 appendStmt(Block, E);
2725 CFGBlock *lastBlock = Block;
2727 // Before that, evaluate all of the semantics in order. In
2728 // CFG-land, that means appending them in reverse order.
2729 for (unsigned i = E->getNumSemanticExprs(); i != 0; ) {
2730 Expr *Semantic = E->getSemanticExpr(--i);
2732 // If the semantic is an opaque value, we're being asked to bind
2733 // it to its source expression.
2734 if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
2735 Semantic = OVE->getSourceExpr();
2737 if (CFGBlock *B = Visit(Semantic))
2744 CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) {
2745 CFGBlock *LoopSuccessor = nullptr;
2747 // Save local scope position because in case of condition variable ScopePos
2748 // won't be restored when traversing AST.
2749 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2751 // Create local scope for possible condition variable.
2752 // Store scope position for continue statement.
2753 LocalScope::const_iterator LoopBeginScopePos = ScopePos;
2754 if (VarDecl *VD = W->getConditionVariable()) {
2755 addLocalScopeForVarDecl(VD);
2756 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W);
2759 // "while" is a control-flow statement. Thus we stop processing the current
2764 LoopSuccessor = Block;
2767 LoopSuccessor = Succ;
2770 CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
2772 // Process the loop body.
2774 assert(W->getBody());
2776 // Save the current values for Block, Succ, continue and break targets.
2777 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
2778 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
2779 save_break(BreakJumpTarget);
2781 // Create an empty block to represent the transition block for looping back
2782 // to the head of the loop.
2783 Succ = TransitionBlock = createBlock(false);
2784 TransitionBlock->setLoopTarget(W);
2785 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos);
2787 // All breaks should go to the code following the loop.
2788 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
2790 // Loop body should end with destructor of Condition variable (if any).
2791 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W);
2793 // If body is not a compound statement create implicit scope
2794 // and add destructors.
2795 if (!isa<CompoundStmt>(W->getBody()))
2796 addLocalScopeAndDtors(W->getBody());
2798 // Create the body. The returned block is the entry to the loop body.
2799 BodyBlock = addStmt(W->getBody());
2802 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;"
2803 else if (Block && badCFG)
2807 // Because of short-circuit evaluation, the condition of the loop can span
2808 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
2809 // evaluate the condition.
2810 CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
2813 Expr *C = W->getCond();
2815 // Specially handle logical operators, which have a slightly
2816 // more optimal CFG representation.
2817 if (BinaryOperator *Cond = dyn_cast<BinaryOperator>(C->IgnoreParens()))
2818 if (Cond->isLogicalOp()) {
2819 std::tie(EntryConditionBlock, ExitConditionBlock) =
2820 VisitLogicalOperator(Cond, W, BodyBlock, LoopSuccessor);
2824 // The default case when not handling logical operators.
2825 ExitConditionBlock = createBlock(false);
2826 ExitConditionBlock->setTerminator(W);
2828 // Now add the actual condition to the condition block.
2829 // Because the condition itself may contain control-flow, new blocks may
2830 // be created. Thus we update "Succ" after adding the condition.
2831 Block = ExitConditionBlock;
2832 Block = EntryConditionBlock = addStmt(C);
2834 // If this block contains a condition variable, add both the condition
2835 // variable and initializer to the CFG.
2836 if (VarDecl *VD = W->getConditionVariable()) {
2837 if (Expr *Init = VD->getInit()) {
2839 appendStmt(Block, W->getConditionVariableDeclStmt());
2840 EntryConditionBlock = addStmt(Init);
2841 assert(Block == EntryConditionBlock);
2845 if (Block && badCFG)
2848 // See if this is a known constant.
2849 const TryResult& KnownVal = tryEvaluateBool(C);
2851 // Add the loop body entry as a successor to the condition.
2852 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
2853 // Link up the condition block with the code that follows the loop. (the
2855 addSuccessor(ExitConditionBlock,
2856 KnownVal.isTrue() ? nullptr : LoopSuccessor);
2860 // Link up the loop-back block to the entry condition block.
2861 addSuccessor(TransitionBlock, EntryConditionBlock);
2863 // There can be no more statements in the condition block since we loop back
2864 // to this block. NULL out Block to force lazy creation of another block.
2867 // Return the condition block, which is the dominating block for the loop.
2868 Succ = EntryConditionBlock;
2869 return EntryConditionBlock;
2873 CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) {
2874 // FIXME: For now we pretend that @catch and the code it contains does not
2879 CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) {
2880 // FIXME: This isn't complete. We basically treat @throw like a return
2883 // If we were in the middle of a block we stop processing that block.
2887 // Create the new block.
2888 Block = createBlock(false);
2890 // The Exit block is the only successor.
2891 addSuccessor(Block, &cfg->getExit());
2893 // Add the statement to the block. This may create new blocks if S contains
2894 // control-flow (short-circuit operations).
2895 return VisitStmt(S, AddStmtChoice::AlwaysAdd);
2898 CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) {
2899 // If we were in the middle of a block we stop processing that block.
2903 // Create the new block.
2904 Block = createBlock(false);
2906 if (TryTerminatedBlock)
2907 // The current try statement is the only successor.
2908 addSuccessor(Block, TryTerminatedBlock);
2910 // otherwise the Exit block is the only successor.
2911 addSuccessor(Block, &cfg->getExit());
2913 // Add the statement to the block. This may create new blocks if S contains
2914 // control-flow (short-circuit operations).
2915 return VisitStmt(T, AddStmtChoice::AlwaysAdd);
2918 CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) {
2919 CFGBlock *LoopSuccessor = nullptr;
2921 // "do...while" is a control-flow statement. Thus we stop processing the
2926 LoopSuccessor = Block;
2928 LoopSuccessor = Succ;
2930 // Because of short-circuit evaluation, the condition of the loop can span
2931 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
2932 // evaluate the condition.
2933 CFGBlock *ExitConditionBlock = createBlock(false);
2934 CFGBlock *EntryConditionBlock = ExitConditionBlock;
2936 // Set the terminator for the "exit" condition block.
2937 ExitConditionBlock->setTerminator(D);
2939 // Now add the actual condition to the condition block. Because the condition
2940 // itself may contain control-flow, new blocks may be created.
2941 if (Stmt *C = D->getCond()) {
2942 Block = ExitConditionBlock;
2943 EntryConditionBlock = addStmt(C);
2950 // The condition block is the implicit successor for the loop body.
2951 Succ = EntryConditionBlock;
2953 // See if this is a known constant.
2954 const TryResult &KnownVal = tryEvaluateBool(D->getCond());
2956 // Process the loop body.
2957 CFGBlock *BodyBlock = nullptr;
2959 assert(D->getBody());
2961 // Save the current values for Block, Succ, and continue and break targets
2962 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
2963 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
2964 save_break(BreakJumpTarget);
2966 // All continues within this loop should go to the condition block
2967 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos);
2969 // All breaks should go to the code following the loop.
2970 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
2972 // NULL out Block to force lazy instantiation of blocks for the body.
2975 // If body is not a compound statement create implicit scope
2976 // and add destructors.
2977 if (!isa<CompoundStmt>(D->getBody()))
2978 addLocalScopeAndDtors(D->getBody());
2980 // Create the body. The returned block is the entry to the loop body.
2981 BodyBlock = addStmt(D->getBody());
2984 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)"
2990 // Add an intermediate block between the BodyBlock and the
2991 // ExitConditionBlock to represent the "loop back" transition. Create an
2992 // empty block to represent the transition block for looping back to the
2993 // head of the loop.
2994 // FIXME: Can we do this more efficiently without adding another block?
2997 CFGBlock *LoopBackBlock = createBlock();
2998 LoopBackBlock->setLoopTarget(D);
3000 if (!KnownVal.isFalse())
3001 // Add the loop body entry as a successor to the condition.
3002 addSuccessor(ExitConditionBlock, LoopBackBlock);
3004 addSuccessor(ExitConditionBlock, nullptr);
3007 // Link up the condition block with the code that follows the loop.
3008 // (the false branch).
3009 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
3011 // There can be no more statements in the body block(s) since we loop back to
3012 // the body. NULL out Block to force lazy creation of another block.
3015 // Return the loop body, which is the dominating block for the loop.
3020 CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) {
3021 // "continue" is a control-flow statement. Thus we stop processing the
3026 // Now create a new block that ends with the continue statement.
3027 Block = createBlock(false);
3028 Block->setTerminator(C);
3030 // If there is no target for the continue, then we are looking at an
3031 // incomplete AST. This means the CFG cannot be constructed.
3032 if (ContinueJumpTarget.block) {
3033 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C);
3034 addSuccessor(Block, ContinueJumpTarget.block);
3041 CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
3042 AddStmtChoice asc) {
3044 if (asc.alwaysAdd(*this, E)) {
3046 appendStmt(Block, E);
3049 // VLA types have expressions that must be evaluated.
3050 CFGBlock *lastBlock = Block;
3052 if (E->isArgumentType()) {
3053 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr());
3054 VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr()))
3055 lastBlock = addStmt(VA->getSizeExpr());
3060 /// VisitStmtExpr - Utility method to handle (nested) statement
3061 /// expressions (a GCC extension).
3062 CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) {
3063 if (asc.alwaysAdd(*this, SE)) {
3065 appendStmt(Block, SE);
3067 return VisitCompoundStmt(SE->getSubStmt());
3070 CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) {
3071 // "switch" is a control-flow statement. Thus we stop processing the current
3073 CFGBlock *SwitchSuccessor = nullptr;
3075 // Save local scope position because in case of condition variable ScopePos
3076 // won't be restored when traversing AST.
3077 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3079 // Create local scope for C++17 switch init-stmt if one exists.
3080 if (Stmt *Init = Terminator->getInit())
3081 addLocalScopeForStmt(Init);
3083 // Create local scope for possible condition variable.
3084 // Store scope position. Add implicit destructor.
3085 if (VarDecl *VD = Terminator->getConditionVariable())
3086 addLocalScopeForVarDecl(VD);
3088 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), Terminator);
3093 SwitchSuccessor = Block;
3094 } else SwitchSuccessor = Succ;
3096 // Save the current "switch" context.
3097 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock),
3098 save_default(DefaultCaseBlock);
3099 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3101 // Set the "default" case to be the block after the switch statement. If the
3102 // switch statement contains a "default:", this value will be overwritten with
3103 // the block for that code.
3104 DefaultCaseBlock = SwitchSuccessor;
3106 // Create a new block that will contain the switch statement.
3107 SwitchTerminatedBlock = createBlock(false);
3109 // Now process the switch body. The code after the switch is the implicit
3111 Succ = SwitchSuccessor;
3112 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos);
3114 // When visiting the body, the case statements should automatically get linked
3115 // up to the switch. We also don't keep a pointer to the body, since all
3116 // control-flow from the switch goes to case/default statements.
3117 assert(Terminator->getBody() && "switch must contain a non-NULL body");
3120 // For pruning unreachable case statements, save the current state
3121 // for tracking the condition value.
3122 SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered,
3125 // Determine if the switch condition can be explicitly evaluated.
3126 assert(Terminator->getCond() && "switch condition must be non-NULL");
3127 Expr::EvalResult result;
3128 bool b = tryEvaluate(Terminator->getCond(), result);
3129 SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond,
3130 b ? &result : nullptr);
3132 // If body is not a compound statement create implicit scope
3133 // and add destructors.
3134 if (!isa<CompoundStmt>(Terminator->getBody()))
3135 addLocalScopeAndDtors(Terminator->getBody());
3137 addStmt(Terminator->getBody());
3143 // If we have no "default:" case, the default transition is to the code
3144 // following the switch body. Moreover, take into account if all the
3145 // cases of a switch are covered (e.g., switching on an enum value).
3147 // Note: We add a successor to a switch that is considered covered yet has no
3148 // case statements if the enumeration has no enumerators.
3149 bool SwitchAlwaysHasSuccessor = false;
3150 SwitchAlwaysHasSuccessor |= switchExclusivelyCovered;
3151 SwitchAlwaysHasSuccessor |= Terminator->isAllEnumCasesCovered() &&
3152 Terminator->getSwitchCaseList();
3153 addSuccessor(SwitchTerminatedBlock, DefaultCaseBlock,
3154 !SwitchAlwaysHasSuccessor);
3156 // Add the terminator and condition in the switch block.
3157 SwitchTerminatedBlock->setTerminator(Terminator);
3158 Block = SwitchTerminatedBlock;
3159 CFGBlock *LastBlock = addStmt(Terminator->getCond());
3161 // If the SwitchStmt contains a condition variable, add both the
3162 // SwitchStmt and the condition variable initialization to the CFG.
3163 if (VarDecl *VD = Terminator->getConditionVariable()) {
3164 if (Expr *Init = VD->getInit()) {
3166 appendStmt(Block, Terminator->getConditionVariableDeclStmt());
3167 LastBlock = addStmt(Init);
3171 // Finally, if the SwitchStmt contains a C++17 init-stmt, add it to the CFG.
3172 if (Stmt *Init = Terminator->getInit()) {
3174 LastBlock = addStmt(Init);
3180 static bool shouldAddCase(bool &switchExclusivelyCovered,
3181 const Expr::EvalResult *switchCond,
3187 bool addCase = false;
3189 if (!switchExclusivelyCovered) {
3190 if (switchCond->Val.isInt()) {
3191 // Evaluate the LHS of the case value.
3192 const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx);
3193 const llvm::APSInt &condInt = switchCond->Val.getInt();
3195 if (condInt == lhsInt) {
3197 switchExclusivelyCovered = true;
3199 else if (condInt > lhsInt) {
3200 if (const Expr *RHS = CS->getRHS()) {
3201 // Evaluate the RHS of the case value.
3202 const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx);
3203 if (V2 >= condInt) {
3205 switchExclusivelyCovered = true;
3216 CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) {
3217 // CaseStmts are essentially labels, so they are the first statement in a
3219 CFGBlock *TopBlock = nullptr, *LastBlock = nullptr;
3221 if (Stmt *Sub = CS->getSubStmt()) {
3222 // For deeply nested chains of CaseStmts, instead of doing a recursion
3223 // (which can blow out the stack), manually unroll and create blocks
3225 while (isa<CaseStmt>(Sub)) {
3226 CFGBlock *currentBlock = createBlock(false);
3227 currentBlock->setLabel(CS);
3230 addSuccessor(LastBlock, currentBlock);
3232 TopBlock = currentBlock;
3234 addSuccessor(SwitchTerminatedBlock,
3235 shouldAddCase(switchExclusivelyCovered, switchCond,
3237 ? currentBlock : nullptr);
3239 LastBlock = currentBlock;
3240 CS = cast<CaseStmt>(Sub);
3241 Sub = CS->getSubStmt();
3247 CFGBlock *CaseBlock = Block;
3249 CaseBlock = createBlock();
3251 // Cases statements partition blocks, so this is the top of the basic block we
3252 // were processing (the "case XXX:" is the label).
3253 CaseBlock->setLabel(CS);
3258 // Add this block to the list of successors for the block with the switch
3260 assert(SwitchTerminatedBlock);
3261 addSuccessor(SwitchTerminatedBlock, CaseBlock,
3262 shouldAddCase(switchExclusivelyCovered, switchCond,
3265 // We set Block to NULL to allow lazy creation of a new block (if necessary)
3269 addSuccessor(LastBlock, CaseBlock);
3272 // This block is now the implicit successor of other blocks.
3279 CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) {
3280 if (Terminator->getSubStmt())
3281 addStmt(Terminator->getSubStmt());
3283 DefaultCaseBlock = Block;
3285 if (!DefaultCaseBlock)
3286 DefaultCaseBlock = createBlock();
3288 // Default statements partition blocks, so this is the top of the basic block
3289 // we were processing (the "default:" is the label).
3290 DefaultCaseBlock->setLabel(Terminator);
3295 // Unlike case statements, we don't add the default block to the successors
3296 // for the switch statement immediately. This is done when we finish
3297 // processing the switch statement. This allows for the default case
3298 // (including a fall-through to the code after the switch statement) to always
3299 // be the last successor of a switch-terminated block.
3301 // We set Block to NULL to allow lazy creation of a new block (if necessary)
3304 // This block is now the implicit successor of other blocks.
3305 Succ = DefaultCaseBlock;
3307 return DefaultCaseBlock;
3310 CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) {
3311 // "try"/"catch" is a control-flow statement. Thus we stop processing the
3313 CFGBlock *TrySuccessor = nullptr;
3318 TrySuccessor = Block;
3319 } else TrySuccessor = Succ;
3321 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock;
3323 // Create a new block that will contain the try statement.
3324 CFGBlock *NewTryTerminatedBlock = createBlock(false);
3325 // Add the terminator in the try block.
3326 NewTryTerminatedBlock->setTerminator(Terminator);
3328 bool HasCatchAll = false;
3329 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) {
3330 // The code after the try is the implicit successor.
3331 Succ = TrySuccessor;
3332 CXXCatchStmt *CS = Terminator->getHandler(h);
3333 if (CS->getExceptionDecl() == nullptr) {
3337 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS);
3340 // Add this block to the list of successors for the block with the try
3342 addSuccessor(NewTryTerminatedBlock, CatchBlock);
3345 if (PrevTryTerminatedBlock)
3346 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock);
3348 addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
3351 // The code after the try is the implicit successor.
3352 Succ = TrySuccessor;
3354 // Save the current "try" context.
3355 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock);
3356 cfg->addTryDispatchBlock(TryTerminatedBlock);
3358 assert(Terminator->getTryBlock() && "try must contain a non-NULL body");
3360 return addStmt(Terminator->getTryBlock());
3363 CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) {
3364 // CXXCatchStmt are treated like labels, so they are the first statement in a
3367 // Save local scope position because in case of exception variable ScopePos
3368 // won't be restored when traversing AST.
3369 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3371 // Create local scope for possible exception variable.
3372 // Store scope position. Add implicit destructor.
3373 if (VarDecl *VD = CS->getExceptionDecl()) {
3374 LocalScope::const_iterator BeginScopePos = ScopePos;
3375 addLocalScopeForVarDecl(VD);
3376 addAutomaticObjDtors(ScopePos, BeginScopePos, CS);
3379 if (CS->getHandlerBlock())
3380 addStmt(CS->getHandlerBlock());
3382 CFGBlock *CatchBlock = Block;
3384 CatchBlock = createBlock();
3386 // CXXCatchStmt is more than just a label. They have semantic meaning
3387 // as well, as they implicitly "initialize" the catch variable. Add
3388 // it to the CFG as a CFGElement so that the control-flow of these
3389 // semantics gets captured.
3390 appendStmt(CatchBlock, CS);
3392 // Also add the CXXCatchStmt as a label, to mirror handling of regular
3394 CatchBlock->setLabel(CS);
3396 // Bail out if the CFG is bad.
3400 // We set Block to NULL to allow lazy creation of a new block (if necessary)
3406 CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) {
3407 // C++0x for-range statements are specified as [stmt.ranged]:
3410 // auto && __range = range-init;
3411 // for ( auto __begin = begin-expr,
3412 // __end = end-expr;
3413 // __begin != __end;
3415 // for-range-declaration = *__begin;
3420 // Save local scope position before the addition of the implicit variables.
3421 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3423 // Create local scopes and destructors for range, begin and end variables.
3424 if (Stmt *Range = S->getRangeStmt())
3425 addLocalScopeForStmt(Range);
3426 if (Stmt *Begin = S->getBeginStmt())
3427 addLocalScopeForStmt(Begin);
3428 if (Stmt *End = S->getEndStmt())
3429 addLocalScopeForStmt(End);
3430 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), S);
3432 LocalScope::const_iterator ContinueScopePos = ScopePos;
3434 // "for" is a control-flow statement. Thus we stop processing the current
3436 CFGBlock *LoopSuccessor = nullptr;
3440 LoopSuccessor = Block;
3442 LoopSuccessor = Succ;
3444 // Save the current value for the break targets.
3445 // All breaks should go to the code following the loop.
3446 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3447 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3449 // The block for the __begin != __end expression.
3450 CFGBlock *ConditionBlock = createBlock(false);
3451 ConditionBlock->setTerminator(S);
3453 // Now add the actual condition to the condition block.
3454 if (Expr *C = S->getCond()) {
3455 Block = ConditionBlock;
3456 CFGBlock *BeginConditionBlock = addStmt(C);
3459 assert(BeginConditionBlock == ConditionBlock &&
3460 "condition block in for-range was unexpectedly complex");
3461 (void)BeginConditionBlock;
3464 // The condition block is the implicit successor for the loop body as well as
3465 // any code above the loop.
3466 Succ = ConditionBlock;
3468 // See if this is a known constant.
3469 TryResult KnownVal(true);
3472 KnownVal = tryEvaluateBool(S->getCond());
3474 // Now create the loop body.
3476 assert(S->getBody());
3478 // Save the current values for Block, Succ, and continue targets.
3479 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3480 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
3482 // Generate increment code in its own basic block. This is the target of
3483 // continue statements.
3485 Succ = addStmt(S->getInc());
3488 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
3490 // The starting block for the loop increment is the block that should
3491 // represent the 'loop target' for looping back to the start of the loop.
3492 ContinueJumpTarget.block->setLoopTarget(S);
3494 // Finish up the increment block and prepare to start the loop body.
3500 // Add implicit scope and dtors for loop variable.
3501 addLocalScopeAndDtors(S->getLoopVarStmt());
3503 // Populate a new block to contain the loop body and loop variable.
3504 addStmt(S->getBody());
3507 CFGBlock *LoopVarStmtBlock = addStmt(S->getLoopVarStmt());
3511 // This new body block is a successor to our condition block.
3512 addSuccessor(ConditionBlock,
3513 KnownVal.isFalse() ? nullptr : LoopVarStmtBlock);
3516 // Link up the condition block with the code that follows the loop (the
3518 addSuccessor(ConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
3520 // Add the initialization statements.
3521 Block = createBlock();
3522 addStmt(S->getBeginStmt());
3523 addStmt(S->getEndStmt());
3524 return addStmt(S->getRangeStmt());
3527 CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E,
3528 AddStmtChoice asc) {
3529 if (BuildOpts.AddTemporaryDtors) {
3530 // If adding implicit destructors visit the full expression for adding
3531 // destructors of temporaries.
3532 TempDtorContext Context;
3533 VisitForTemporaryDtors(E->getSubExpr(), false, Context);
3535 // Full expression has to be added as CFGStmt so it will be sequenced
3536 // before destructors of it's temporaries.
3537 asc = asc.withAlwaysAdd(true);
3539 return Visit(E->getSubExpr(), asc);
3542 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
3543 AddStmtChoice asc) {
3544 if (asc.alwaysAdd(*this, E)) {
3546 appendStmt(Block, E);
3548 // We do not want to propagate the AlwaysAdd property.
3549 asc = asc.withAlwaysAdd(false);
3551 return Visit(E->getSubExpr(), asc);
3554 CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C,
3555 AddStmtChoice asc) {
3557 appendStmt(Block, C);
3559 return VisitChildren(C);
3562 CFGBlock *CFGBuilder::VisitCXXNewExpr(CXXNewExpr *NE,
3563 AddStmtChoice asc) {
3566 appendStmt(Block, NE);
3568 if (NE->getInitializer())
3569 Block = Visit(NE->getInitializer());
3570 if (BuildOpts.AddCXXNewAllocator)
3571 appendNewAllocator(Block, NE);
3573 Block = Visit(NE->getArraySize());
3574 for (CXXNewExpr::arg_iterator I = NE->placement_arg_begin(),
3575 E = NE->placement_arg_end(); I != E; ++I)
3580 CFGBlock *CFGBuilder::VisitCXXDeleteExpr(CXXDeleteExpr *DE,
3581 AddStmtChoice asc) {
3583 appendStmt(Block, DE);
3584 QualType DTy = DE->getDestroyedType();
3585 if (!DTy.isNull()) {
3586 DTy = DTy.getNonReferenceType();
3587 CXXRecordDecl *RD = Context->getBaseElementType(DTy)->getAsCXXRecordDecl();
3589 if (RD->isCompleteDefinition() && !RD->hasTrivialDestructor())
3590 appendDeleteDtor(Block, RD, DE);
3594 return VisitChildren(DE);
3597 CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
3598 AddStmtChoice asc) {
3599 if (asc.alwaysAdd(*this, E)) {
3601 appendStmt(Block, E);
3602 // We do not want to propagate the AlwaysAdd property.
3603 asc = asc.withAlwaysAdd(false);
3605 return Visit(E->getSubExpr(), asc);
3608 CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
3609 AddStmtChoice asc) {
3611 appendStmt(Block, C);
3612 return VisitChildren(C);
3615 CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E,
3616 AddStmtChoice asc) {
3617 if (asc.alwaysAdd(*this, E)) {
3619 appendStmt(Block, E);
3621 return Visit(E->getSubExpr(), AddStmtChoice());
3624 CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) {
3625 // Lazily create the indirect-goto dispatch block if there isn't one already.
3626 CFGBlock *IBlock = cfg->getIndirectGotoBlock();
3629 IBlock = createBlock(false);
3630 cfg->setIndirectGotoBlock(IBlock);
3633 // IndirectGoto is a control-flow statement. Thus we stop processing the
3634 // current block and create a new one.
3638 Block = createBlock(false);
3639 Block->setTerminator(I);
3640 addSuccessor(Block, IBlock);
3641 return addStmt(I->getTarget());
3644 CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary,
3645 TempDtorContext &Context) {
3646 assert(BuildOpts.AddImplicitDtors && BuildOpts.AddTemporaryDtors);
3653 switch (E->getStmtClass()) {
3655 return VisitChildrenForTemporaryDtors(E, Context);
3657 case Stmt::BinaryOperatorClass:
3658 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E),
3661 case Stmt::CXXBindTemporaryExprClass:
3662 return VisitCXXBindTemporaryExprForTemporaryDtors(
3663 cast<CXXBindTemporaryExpr>(E), BindToTemporary, Context);
3665 case Stmt::BinaryConditionalOperatorClass:
3666 case Stmt::ConditionalOperatorClass:
3667 return VisitConditionalOperatorForTemporaryDtors(
3668 cast<AbstractConditionalOperator>(E), BindToTemporary, Context);
3670 case Stmt::ImplicitCastExprClass:
3671 // For implicit cast we want BindToTemporary to be passed further.
3672 E = cast<CastExpr>(E)->getSubExpr();
3675 case Stmt::CXXFunctionalCastExprClass:
3676 // For functional cast we want BindToTemporary to be passed further.
3677 E = cast<CXXFunctionalCastExpr>(E)->getSubExpr();
3680 case Stmt::ParenExprClass:
3681 E = cast<ParenExpr>(E)->getSubExpr();
3684 case Stmt::MaterializeTemporaryExprClass: {
3685 const MaterializeTemporaryExpr* MTE = cast<MaterializeTemporaryExpr>(E);
3686 BindToTemporary = (MTE->getStorageDuration() != SD_FullExpression);
3687 SmallVector<const Expr *, 2> CommaLHSs;
3688 SmallVector<SubobjectAdjustment, 2> Adjustments;
3689 // Find the expression whose lifetime needs to be extended.
3690 E = const_cast<Expr *>(
3691 cast<MaterializeTemporaryExpr>(E)
3692 ->GetTemporaryExpr()
3693 ->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments));
3694 // Visit the skipped comma operator left-hand sides for other temporaries.
3695 for (const Expr *CommaLHS : CommaLHSs) {
3696 VisitForTemporaryDtors(const_cast<Expr *>(CommaLHS),
3697 /*BindToTemporary=*/false, Context);
3702 case Stmt::BlockExprClass:
3703 // Don't recurse into blocks; their subexpressions don't get evaluated
3707 case Stmt::LambdaExprClass: {
3708 // For lambda expressions, only recurse into the capture initializers,
3709 // and not the body.
3710 auto *LE = cast<LambdaExpr>(E);
3711 CFGBlock *B = Block;
3712 for (Expr *Init : LE->capture_inits()) {
3713 if (CFGBlock *R = VisitForTemporaryDtors(
3714 Init, /*BindToTemporary=*/false, Context))
3720 case Stmt::CXXDefaultArgExprClass:
3721 E = cast<CXXDefaultArgExpr>(E)->getExpr();
3724 case Stmt::CXXDefaultInitExprClass:
3725 E = cast<CXXDefaultInitExpr>(E)->getExpr();
3730 CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E,
3731 TempDtorContext &Context) {
3732 if (isa<LambdaExpr>(E)) {
3733 // Do not visit the children of lambdas; they have their own CFGs.
3737 // When visiting children for destructors we want to visit them in reverse
3738 // order that they will appear in the CFG. Because the CFG is built
3739 // bottom-up, this means we visit them in their natural order, which
3740 // reverses them in the CFG.
3741 CFGBlock *B = Block;
3742 for (Stmt *Child : E->children())
3744 if (CFGBlock *R = VisitForTemporaryDtors(Child, false, Context))
3750 CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(
3751 BinaryOperator *E, TempDtorContext &Context) {
3752 if (E->isLogicalOp()) {
3753 VisitForTemporaryDtors(E->getLHS(), false, Context);
3754 TryResult RHSExecuted = tryEvaluateBool(E->getLHS());
3755 if (RHSExecuted.isKnown() && E->getOpcode() == BO_LOr)
3756 RHSExecuted.negate();
3758 // We do not know at CFG-construction time whether the right-hand-side was
3759 // executed, thus we add a branch node that depends on the temporary
3760 // constructor call.
3761 TempDtorContext RHSContext(
3762 bothKnownTrue(Context.KnownExecuted, RHSExecuted));
3763 VisitForTemporaryDtors(E->getRHS(), false, RHSContext);
3764 InsertTempDtorDecisionBlock(RHSContext);
3769 if (E->isAssignmentOp()) {
3770 // For assignment operator (=) LHS expression is visited
3771 // before RHS expression. For destructors visit them in reverse order.
3772 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
3773 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
3774 return LHSBlock ? LHSBlock : RHSBlock;
3777 // For any other binary operator RHS expression is visited before
3778 // LHS expression (order of children). For destructors visit them in reverse
3780 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
3781 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
3782 return RHSBlock ? RHSBlock : LHSBlock;
3785 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors(
3786 CXXBindTemporaryExpr *E, bool BindToTemporary, TempDtorContext &Context) {
3787 // First add destructors for temporaries in subexpression.
3788 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr(), false, Context);
3789 if (!BindToTemporary) {
3790 // If lifetime of temporary is not prolonged (by assigning to constant
3791 // reference) add destructor for it.
3793 const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor();
3795 if (Dtor->getParent()->isAnyDestructorNoReturn()) {
3796 // If the destructor is marked as a no-return destructor, we need to
3797 // create a new block for the destructor which does not have as a
3798 // successor anything built thus far. Control won't flow out of this
3801 Block = createNoReturnBlock();
3802 } else if (Context.needsTempDtorBranch()) {
3803 // If we need to introduce a branch, we add a new block that we will hook
3804 // up to a decision block later.
3806 Block = createBlock();
3810 if (Context.needsTempDtorBranch()) {
3811 Context.setDecisionPoint(Succ, E);
3813 appendTemporaryDtor(Block, E);
3820 void CFGBuilder::InsertTempDtorDecisionBlock(const TempDtorContext &Context,
3821 CFGBlock *FalseSucc) {
3822 if (!Context.TerminatorExpr) {
3823 // If no temporary was found, we do not need to insert a decision point.
3826 assert(Context.TerminatorExpr);
3827 CFGBlock *Decision = createBlock(false);
3828 Decision->setTerminator(CFGTerminator(Context.TerminatorExpr, true));
3829 addSuccessor(Decision, Block, !Context.KnownExecuted.isFalse());
3830 addSuccessor(Decision, FalseSucc ? FalseSucc : Context.Succ,
3831 !Context.KnownExecuted.isTrue());
3835 CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors(
3836 AbstractConditionalOperator *E, bool BindToTemporary,
3837 TempDtorContext &Context) {
3838 VisitForTemporaryDtors(E->getCond(), false, Context);
3839 CFGBlock *ConditionBlock = Block;
3840 CFGBlock *ConditionSucc = Succ;
3841 TryResult ConditionVal = tryEvaluateBool(E->getCond());
3842 TryResult NegatedVal = ConditionVal;
3843 if (NegatedVal.isKnown()) NegatedVal.negate();
3845 TempDtorContext TrueContext(
3846 bothKnownTrue(Context.KnownExecuted, ConditionVal));
3847 VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary, TrueContext);
3848 CFGBlock *TrueBlock = Block;
3850 Block = ConditionBlock;
3851 Succ = ConditionSucc;
3852 TempDtorContext FalseContext(
3853 bothKnownTrue(Context.KnownExecuted, NegatedVal));
3854 VisitForTemporaryDtors(E->getFalseExpr(), BindToTemporary, FalseContext);
3856 if (TrueContext.TerminatorExpr && FalseContext.TerminatorExpr) {
3857 InsertTempDtorDecisionBlock(FalseContext, TrueBlock);
3858 } else if (TrueContext.TerminatorExpr) {
3860 InsertTempDtorDecisionBlock(TrueContext);
3862 InsertTempDtorDecisionBlock(FalseContext);
3867 } // end anonymous namespace
3869 /// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has
3870 /// no successors or predecessors. If this is the first block created in the
3871 /// CFG, it is automatically set to be the Entry and Exit of the CFG.
3872 CFGBlock *CFG::createBlock() {
3873 bool first_block = begin() == end();
3875 // Create the block.
3876 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>();
3877 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this);
3878 Blocks.push_back(Mem, BlkBVC);
3880 // If this is the first block, set it as the Entry and Exit.
3882 Entry = Exit = &back();
3884 // Return the block.
3888 /// buildCFG - Constructs a CFG from an AST.
3889 std::unique_ptr<CFG> CFG::buildCFG(const Decl *D, Stmt *Statement,
3890 ASTContext *C, const BuildOptions &BO) {
3891 CFGBuilder Builder(C, BO);
3892 return Builder.buildCFG(D, Statement);
3895 const CXXDestructorDecl *
3896 CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const {
3897 switch (getKind()) {
3898 case CFGElement::Statement:
3899 case CFGElement::Initializer:
3900 case CFGElement::NewAllocator:
3901 llvm_unreachable("getDestructorDecl should only be used with "
3903 case CFGElement::AutomaticObjectDtor: {
3904 const VarDecl *var = castAs<CFGAutomaticObjDtor>().getVarDecl();
3905 QualType ty = var->getType();
3907 // FIXME: See CFGBuilder::addLocalScopeForVarDecl.
3909 // Lifetime-extending constructs are handled here. This works for a single
3910 // temporary in an initializer expression.
3911 if (ty->isReferenceType()) {
3912 if (const Expr *Init = var->getInit()) {
3913 ty = getReferenceInitTemporaryType(astContext, Init);
3917 while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) {
3918 ty = arrayType->getElementType();
3920 const RecordType *recordType = ty->getAs<RecordType>();
3921 const CXXRecordDecl *classDecl =
3922 cast<CXXRecordDecl>(recordType->getDecl());
3923 return classDecl->getDestructor();
3925 case CFGElement::DeleteDtor: {
3926 const CXXDeleteExpr *DE = castAs<CFGDeleteDtor>().getDeleteExpr();
3927 QualType DTy = DE->getDestroyedType();
3928 DTy = DTy.getNonReferenceType();
3929 const CXXRecordDecl *classDecl =
3930 astContext.getBaseElementType(DTy)->getAsCXXRecordDecl();
3931 return classDecl->getDestructor();
3933 case CFGElement::TemporaryDtor: {
3934 const CXXBindTemporaryExpr *bindExpr =
3935 castAs<CFGTemporaryDtor>().getBindTemporaryExpr();
3936 const CXXTemporary *temp = bindExpr->getTemporary();
3937 return temp->getDestructor();
3939 case CFGElement::BaseDtor:
3940 case CFGElement::MemberDtor:
3942 // Not yet supported.
3945 llvm_unreachable("getKind() returned bogus value");
3948 bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const {
3949 if (const CXXDestructorDecl *DD = getDestructorDecl(astContext))
3950 return DD->isNoReturn();
3954 //===----------------------------------------------------------------------===//
3955 // CFGBlock operations.
3956 //===----------------------------------------------------------------------===//
3958 CFGBlock::AdjacentBlock::AdjacentBlock(CFGBlock *B, bool IsReachable)
3959 : ReachableBlock(IsReachable ? B : nullptr),
3960 UnreachableBlock(!IsReachable ? B : nullptr,
3961 B && IsReachable ? AB_Normal : AB_Unreachable) {}
3963 CFGBlock::AdjacentBlock::AdjacentBlock(CFGBlock *B, CFGBlock *AlternateBlock)
3964 : ReachableBlock(B),
3965 UnreachableBlock(B == AlternateBlock ? nullptr : AlternateBlock,
3966 B == AlternateBlock ? AB_Alternate : AB_Normal) {}
3968 void CFGBlock::addSuccessor(AdjacentBlock Succ,
3969 BumpVectorContext &C) {
3970 if (CFGBlock *B = Succ.getReachableBlock())
3971 B->Preds.push_back(AdjacentBlock(this, Succ.isReachable()), C);
3973 if (CFGBlock *UnreachableB = Succ.getPossiblyUnreachableBlock())
3974 UnreachableB->Preds.push_back(AdjacentBlock(this, false), C);
3976 Succs.push_back(Succ, C);
3979 bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F,
3980 const CFGBlock *From, const CFGBlock *To) {
3982 if (F.IgnoreNullPredecessors && !From)
3985 if (To && From && F.IgnoreDefaultsWithCoveredEnums) {
3986 // If the 'To' has no label or is labeled but the label isn't a
3987 // CaseStmt then filter this edge.
3988 if (const SwitchStmt *S =
3989 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) {
3990 if (S->isAllEnumCasesCovered()) {
3991 const Stmt *L = To->getLabel();
3992 if (!L || !isa<CaseStmt>(L))
4001 //===----------------------------------------------------------------------===//
4002 // CFG pretty printing
4003 //===----------------------------------------------------------------------===//
4007 class StmtPrinterHelper : public PrinterHelper {
4008 typedef llvm::DenseMap<const Stmt*,std::pair<unsigned,unsigned> > StmtMapTy;
4009 typedef llvm::DenseMap<const Decl*,std::pair<unsigned,unsigned> > DeclMapTy;
4012 signed currentBlock;
4014 const LangOptions &LangOpts;
4017 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO)
4018 : currentBlock(0), currStmt(0), LangOpts(LO)
4020 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) {
4022 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ;
4023 BI != BEnd; ++BI, ++j ) {
4024 if (Optional<CFGStmt> SE = BI->getAs<CFGStmt>()) {
4025 const Stmt *stmt= SE->getStmt();
4026 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j);
4029 switch (stmt->getStmtClass()) {
4030 case Stmt::DeclStmtClass:
4031 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P;
4033 case Stmt::IfStmtClass: {
4034 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable();
4039 case Stmt::ForStmtClass: {
4040 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable();
4045 case Stmt::WhileStmtClass: {
4046 const VarDecl *var =
4047 cast<WhileStmt>(stmt)->getConditionVariable();
4052 case Stmt::SwitchStmtClass: {
4053 const VarDecl *var =
4054 cast<SwitchStmt>(stmt)->getConditionVariable();
4059 case Stmt::CXXCatchStmtClass: {
4060 const VarDecl *var =
4061 cast<CXXCatchStmt>(stmt)->getExceptionDecl();
4074 ~StmtPrinterHelper() override {}
4076 const LangOptions &getLangOpts() const { return LangOpts; }
4077 void setBlockID(signed i) { currentBlock = i; }
4078 void setStmtID(unsigned i) { currStmt = i; }
4080 bool handledStmt(Stmt *S, raw_ostream &OS) override {
4081 StmtMapTy::iterator I = StmtMap.find(S);
4083 if (I == StmtMap.end())
4086 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
4087 && I->second.second == currStmt) {
4091 OS << "[B" << I->second.first << "." << I->second.second << "]";
4095 bool handleDecl(const Decl *D, raw_ostream &OS) {
4096 DeclMapTy::iterator I = DeclMap.find(D);
4098 if (I == DeclMap.end())
4101 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
4102 && I->second.second == currStmt) {
4106 OS << "[B" << I->second.first << "." << I->second.second << "]";
4110 } // end anonymous namespace
4114 class CFGBlockTerminatorPrint
4115 : public StmtVisitor<CFGBlockTerminatorPrint,void> {
4118 StmtPrinterHelper* Helper;
4119 PrintingPolicy Policy;
4121 CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper,
4122 const PrintingPolicy &Policy)
4123 : OS(os), Helper(helper), Policy(Policy) {
4124 this->Policy.IncludeNewlines = false;
4127 void VisitIfStmt(IfStmt *I) {
4129 if (Stmt *C = I->getCond())
4130 C->printPretty(OS, Helper, Policy);
4134 void VisitStmt(Stmt *Terminator) {
4135 Terminator->printPretty(OS, Helper, Policy);
4138 void VisitDeclStmt(DeclStmt *DS) {
4139 VarDecl *VD = cast<VarDecl>(DS->getSingleDecl());
4140 OS << "static init " << VD->getName();
4143 void VisitForStmt(ForStmt *F) {
4148 if (Stmt *C = F->getCond())
4149 C->printPretty(OS, Helper, Policy);
4156 void VisitWhileStmt(WhileStmt *W) {
4158 if (Stmt *C = W->getCond())
4159 C->printPretty(OS, Helper, Policy);
4162 void VisitDoStmt(DoStmt *D) {
4163 OS << "do ... while ";
4164 if (Stmt *C = D->getCond())
4165 C->printPretty(OS, Helper, Policy);
4168 void VisitSwitchStmt(SwitchStmt *Terminator) {
4170 Terminator->getCond()->printPretty(OS, Helper, Policy);
4173 void VisitCXXTryStmt(CXXTryStmt *CS) {
4177 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) {
4178 if (Stmt *Cond = C->getCond())
4179 Cond->printPretty(OS, Helper, Policy);
4180 OS << " ? ... : ...";
4183 void VisitChooseExpr(ChooseExpr *C) {
4184 OS << "__builtin_choose_expr( ";
4185 if (Stmt *Cond = C->getCond())
4186 Cond->printPretty(OS, Helper, Policy);
4190 void VisitIndirectGotoStmt(IndirectGotoStmt *I) {
4192 if (Stmt *T = I->getTarget())
4193 T->printPretty(OS, Helper, Policy);
4196 void VisitBinaryOperator(BinaryOperator* B) {
4197 if (!B->isLogicalOp()) {
4203 B->getLHS()->printPretty(OS, Helper, Policy);
4205 switch (B->getOpcode()) {
4213 llvm_unreachable("Invalid logical operator.");
4217 void VisitExpr(Expr *E) {
4218 E->printPretty(OS, Helper, Policy);
4222 void print(CFGTerminator T) {
4223 if (T.isTemporaryDtorsBranch())
4224 OS << "(Temp Dtor) ";
4228 } // end anonymous namespace
4230 static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
4231 const CFGElement &E) {
4232 if (Optional<CFGStmt> CS = E.getAs<CFGStmt>()) {
4233 const Stmt *S = CS->getStmt();
4234 assert(S != nullptr && "Expecting non-null Stmt");
4236 // special printing for statement-expressions.
4237 if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) {
4238 const CompoundStmt *Sub = SE->getSubStmt();
4240 auto Children = Sub->children();
4241 if (Children.begin() != Children.end()) {
4243 Helper.handledStmt(*SE->getSubStmt()->body_rbegin(),OS);
4248 // special printing for comma expressions.
4249 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) {
4250 if (B->getOpcode() == BO_Comma) {
4252 Helper.handledStmt(B->getRHS(),OS);
4257 S->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
4259 if (isa<CXXOperatorCallExpr>(S)) {
4260 OS << " (OperatorCall)";
4262 else if (isa<CXXBindTemporaryExpr>(S)) {
4263 OS << " (BindTemporary)";
4265 else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) {
4266 OS << " (CXXConstructExpr, " << CCE->getType().getAsString() << ")";
4268 else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) {
4269 OS << " (" << CE->getStmtClassName() << ", "
4270 << CE->getCastKindName()
4271 << ", " << CE->getType().getAsString()
4275 // Expressions need a newline.
4279 } else if (Optional<CFGInitializer> IE = E.getAs<CFGInitializer>()) {
4280 const CXXCtorInitializer *I = IE->getInitializer();
4281 if (I->isBaseInitializer())
4282 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName();
4283 else if (I->isDelegatingInitializer())
4284 OS << I->getTypeSourceInfo()->getType()->getAsCXXRecordDecl()->getName();
4285 else OS << I->getAnyMember()->getName();
4288 if (Expr *IE = I->getInit())
4289 IE->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
4292 if (I->isBaseInitializer())
4293 OS << " (Base initializer)\n";
4294 else if (I->isDelegatingInitializer())
4295 OS << " (Delegating initializer)\n";
4296 else OS << " (Member initializer)\n";
4298 } else if (Optional<CFGAutomaticObjDtor> DE =
4299 E.getAs<CFGAutomaticObjDtor>()) {
4300 const VarDecl *VD = DE->getVarDecl();
4301 Helper.handleDecl(VD, OS);
4303 const Type* T = VD->getType().getTypePtr();
4304 if (const ReferenceType* RT = T->getAs<ReferenceType>())
4305 T = RT->getPointeeType().getTypePtr();
4306 T = T->getBaseElementTypeUnsafe();
4308 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()";
4309 OS << " (Implicit destructor)\n";
4311 } else if (Optional<CFGNewAllocator> NE = E.getAs<CFGNewAllocator>()) {
4312 OS << "CFGNewAllocator(";
4313 if (const CXXNewExpr *AllocExpr = NE->getAllocatorExpr())
4314 AllocExpr->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
4316 } else if (Optional<CFGDeleteDtor> DE = E.getAs<CFGDeleteDtor>()) {
4317 const CXXRecordDecl *RD = DE->getCXXRecordDecl();
4320 CXXDeleteExpr *DelExpr =
4321 const_cast<CXXDeleteExpr*>(DE->getDeleteExpr());
4322 Helper.handledStmt(cast<Stmt>(DelExpr->getArgument()), OS);
4323 OS << "->~" << RD->getName().str() << "()";
4324 OS << " (Implicit destructor)\n";
4325 } else if (Optional<CFGBaseDtor> BE = E.getAs<CFGBaseDtor>()) {
4326 const CXXBaseSpecifier *BS = BE->getBaseSpecifier();
4327 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()";
4328 OS << " (Base object destructor)\n";
4330 } else if (Optional<CFGMemberDtor> ME = E.getAs<CFGMemberDtor>()) {
4331 const FieldDecl *FD = ME->getFieldDecl();
4332 const Type *T = FD->getType()->getBaseElementTypeUnsafe();
4333 OS << "this->" << FD->getName();
4334 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()";
4335 OS << " (Member object destructor)\n";
4337 } else if (Optional<CFGTemporaryDtor> TE = E.getAs<CFGTemporaryDtor>()) {
4338 const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr();
4340 BT->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
4341 OS << "() (Temporary object destructor)\n";
4345 static void print_block(raw_ostream &OS, const CFG* cfg,
4347 StmtPrinterHelper &Helper, bool print_edges,
4350 Helper.setBlockID(B.getBlockID());
4352 // Print the header.
4354 OS.changeColor(raw_ostream::YELLOW, true);
4356 OS << "\n [B" << B.getBlockID();
4358 if (&B == &cfg->getEntry())
4359 OS << " (ENTRY)]\n";
4360 else if (&B == &cfg->getExit())
4362 else if (&B == cfg->getIndirectGotoBlock())
4363 OS << " (INDIRECT GOTO DISPATCH)]\n";
4364 else if (B.hasNoReturnElement())
4365 OS << " (NORETURN)]\n";
4372 // Print the label of this block.
4373 if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) {
4378 if (LabelStmt *L = dyn_cast<LabelStmt>(Label))
4380 else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) {
4383 C->getLHS()->printPretty(OS, &Helper,
4384 PrintingPolicy(Helper.getLangOpts()));
4387 C->getRHS()->printPretty(OS, &Helper,
4388 PrintingPolicy(Helper.getLangOpts()));
4390 } else if (isa<DefaultStmt>(Label))
4392 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) {
4394 if (CS->getExceptionDecl())
4395 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper.getLangOpts()),
4402 llvm_unreachable("Invalid label statement in CFGBlock.");
4407 // Iterate through the statements in the block and print them.
4410 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ;
4411 I != E ; ++I, ++j ) {
4413 // Print the statement # in the basic block and the statement itself.
4417 OS << llvm::format("%3d", j) << ": ";
4419 Helper.setStmtID(j);
4421 print_elem(OS, Helper, *I);
4424 // Print the terminator of this block.
4425 if (B.getTerminator()) {
4427 OS.changeColor(raw_ostream::GREEN);
4431 Helper.setBlockID(-1);
4433 PrintingPolicy PP(Helper.getLangOpts());
4434 CFGBlockTerminatorPrint TPrinter(OS, &Helper, PP);
4435 TPrinter.print(B.getTerminator());
4443 // Print the predecessors of this block.
4444 if (!B.pred_empty()) {
4445 const raw_ostream::Colors Color = raw_ostream::BLUE;
4447 OS.changeColor(Color);
4451 OS << '(' << B.pred_size() << "):";
4455 OS.changeColor(Color);
4457 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end();
4464 bool Reachable = true;
4467 B = I->getPossiblyUnreachableBlock();
4470 OS << " B" << B->getBlockID();
4472 OS << "(Unreachable)";
4481 // Print the successors of this block.
4482 if (!B.succ_empty()) {
4483 const raw_ostream::Colors Color = raw_ostream::MAGENTA;
4485 OS.changeColor(Color);
4489 OS << '(' << B.succ_size() << "):";
4493 OS.changeColor(Color);
4495 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end();
4503 bool Reachable = true;
4506 B = I->getPossiblyUnreachableBlock();
4510 OS << " B" << B->getBlockID();
4512 OS << "(Unreachable)";
4527 /// dump - A simple pretty printer of a CFG that outputs to stderr.
4528 void CFG::dump(const LangOptions &LO, bool ShowColors) const {
4529 print(llvm::errs(), LO, ShowColors);
4532 /// print - A simple pretty printer of a CFG that outputs to an ostream.
4533 void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const {
4534 StmtPrinterHelper Helper(this, LO);
4536 // Print the entry block.
4537 print_block(OS, this, getEntry(), Helper, true, ShowColors);
4539 // Iterate through the CFGBlocks and print them one by one.
4540 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) {
4541 // Skip the entry block, because we already printed it.
4542 if (&(**I) == &getEntry() || &(**I) == &getExit())
4545 print_block(OS, this, **I, Helper, true, ShowColors);
4548 // Print the exit block.
4549 print_block(OS, this, getExit(), Helper, true, ShowColors);
4554 /// dump - A simply pretty printer of a CFGBlock that outputs to stderr.
4555 void CFGBlock::dump(const CFG* cfg, const LangOptions &LO,
4556 bool ShowColors) const {
4557 print(llvm::errs(), cfg, LO, ShowColors);
4560 LLVM_DUMP_METHOD void CFGBlock::dump() const {
4561 dump(getParent(), LangOptions(), false);
4564 /// print - A simple pretty printer of a CFGBlock that outputs to an ostream.
4565 /// Generally this will only be called from CFG::print.
4566 void CFGBlock::print(raw_ostream &OS, const CFG* cfg,
4567 const LangOptions &LO, bool ShowColors) const {
4568 StmtPrinterHelper Helper(cfg, LO);
4569 print_block(OS, cfg, *this, Helper, true, ShowColors);
4573 /// printTerminator - A simple pretty printer of the terminator of a CFGBlock.
4574 void CFGBlock::printTerminator(raw_ostream &OS,
4575 const LangOptions &LO) const {
4576 CFGBlockTerminatorPrint TPrinter(OS, nullptr, PrintingPolicy(LO));
4577 TPrinter.print(getTerminator());
4580 Stmt *CFGBlock::getTerminatorCondition(bool StripParens) {
4581 Stmt *Terminator = this->Terminator;
4587 switch (Terminator->getStmtClass()) {
4591 case Stmt::CXXForRangeStmtClass:
4592 E = cast<CXXForRangeStmt>(Terminator)->getCond();
4595 case Stmt::ForStmtClass:
4596 E = cast<ForStmt>(Terminator)->getCond();
4599 case Stmt::WhileStmtClass:
4600 E = cast<WhileStmt>(Terminator)->getCond();
4603 case Stmt::DoStmtClass:
4604 E = cast<DoStmt>(Terminator)->getCond();
4607 case Stmt::IfStmtClass:
4608 E = cast<IfStmt>(Terminator)->getCond();
4611 case Stmt::ChooseExprClass:
4612 E = cast<ChooseExpr>(Terminator)->getCond();
4615 case Stmt::IndirectGotoStmtClass:
4616 E = cast<IndirectGotoStmt>(Terminator)->getTarget();
4619 case Stmt::SwitchStmtClass:
4620 E = cast<SwitchStmt>(Terminator)->getCond();
4623 case Stmt::BinaryConditionalOperatorClass:
4624 E = cast<BinaryConditionalOperator>(Terminator)->getCond();
4627 case Stmt::ConditionalOperatorClass:
4628 E = cast<ConditionalOperator>(Terminator)->getCond();
4631 case Stmt::BinaryOperatorClass: // '&&' and '||'
4632 E = cast<BinaryOperator>(Terminator)->getLHS();
4635 case Stmt::ObjCForCollectionStmtClass:
4642 return E ? E->IgnoreParens() : nullptr;
4645 //===----------------------------------------------------------------------===//
4646 // CFG Graphviz Visualization
4647 //===----------------------------------------------------------------------===//
4651 static StmtPrinterHelper* GraphHelper;
4654 void CFG::viewCFG(const LangOptions &LO) const {
4656 StmtPrinterHelper H(this, LO);
4658 llvm::ViewGraph(this,"CFG");
4659 GraphHelper = nullptr;
4665 struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits {
4667 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
4669 static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) {
4672 std::string OutSStr;
4673 llvm::raw_string_ostream Out(OutSStr);
4674 print_block(Out,Graph, *Node, *GraphHelper, false, false);
4675 std::string& OutStr = Out.str();
4677 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
4679 // Process string output to make it nicer...
4680 for (unsigned i = 0; i != OutStr.length(); ++i)
4681 if (OutStr[i] == '\n') { // Left justify
4683 OutStr.insert(OutStr.begin()+i+1, 'l');
4692 } // end namespace llvm