1 //===- CFG.cpp - Classes for representing and building CFGs ---------------===//
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/Decl.h"
19 #include "clang/AST/DeclBase.h"
20 #include "clang/AST/DeclCXX.h"
21 #include "clang/AST/DeclGroup.h"
22 #include "clang/AST/Expr.h"
23 #include "clang/AST/ExprCXX.h"
24 #include "clang/AST/OperationKinds.h"
25 #include "clang/AST/PrettyPrinter.h"
26 #include "clang/AST/Stmt.h"
27 #include "clang/AST/StmtCXX.h"
28 #include "clang/AST/StmtObjC.h"
29 #include "clang/AST/StmtVisitor.h"
30 #include "clang/AST/Type.h"
31 #include "clang/Analysis/Support/BumpVector.h"
32 #include "clang/Analysis/ConstructionContext.h"
33 #include "clang/Basic/Builtins.h"
34 #include "clang/Basic/ExceptionSpecificationType.h"
35 #include "clang/Basic/LLVM.h"
36 #include "clang/Basic/LangOptions.h"
37 #include "clang/Basic/SourceLocation.h"
38 #include "clang/Basic/Specifiers.h"
39 #include "llvm/ADT/APInt.h"
40 #include "llvm/ADT/APSInt.h"
41 #include "llvm/ADT/ArrayRef.h"
42 #include "llvm/ADT/DenseMap.h"
43 #include "llvm/ADT/Optional.h"
44 #include "llvm/ADT/STLExtras.h"
45 #include "llvm/ADT/SetVector.h"
46 #include "llvm/ADT/SmallPtrSet.h"
47 #include "llvm/ADT/SmallVector.h"
48 #include "llvm/Support/Allocator.h"
49 #include "llvm/Support/Casting.h"
50 #include "llvm/Support/Compiler.h"
51 #include "llvm/Support/DOTGraphTraits.h"
52 #include "llvm/Support/ErrorHandling.h"
53 #include "llvm/Support/Format.h"
54 #include "llvm/Support/GraphWriter.h"
55 #include "llvm/Support/SaveAndRestore.h"
56 #include "llvm/Support/raw_ostream.h"
64 using namespace clang;
66 static SourceLocation GetEndLoc(Decl *D) {
67 if (VarDecl *VD = dyn_cast<VarDecl>(D))
68 if (Expr *Ex = VD->getInit())
69 return Ex->getSourceRange().getEnd();
70 return D->getLocation();
73 /// Helper for tryNormalizeBinaryOperator. Attempts to extract an IntegerLiteral
74 /// or EnumConstantDecl from the given Expr. If it fails, returns nullptr.
75 static const Expr *tryTransformToIntOrEnumConstant(const Expr *E) {
76 E = E->IgnoreParens();
77 if (isa<IntegerLiteral>(E))
79 if (auto *DR = dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))
80 return isa<EnumConstantDecl>(DR->getDecl()) ? DR : nullptr;
84 /// Tries to interpret a binary operator into `Decl Op Expr` form, if Expr is
85 /// an integer literal or an enum constant.
87 /// If this fails, at least one of the returned DeclRefExpr or Expr will be
89 static std::tuple<const DeclRefExpr *, BinaryOperatorKind, const Expr *>
90 tryNormalizeBinaryOperator(const BinaryOperator *B) {
91 BinaryOperatorKind Op = B->getOpcode();
93 const Expr *MaybeDecl = B->getLHS();
94 const Expr *Constant = tryTransformToIntOrEnumConstant(B->getRHS());
95 // Expr looked like `0 == Foo` instead of `Foo == 0`
96 if (Constant == nullptr) {
100 else if (Op == BO_GE)
102 else if (Op == BO_LT)
104 else if (Op == BO_LE)
107 MaybeDecl = B->getRHS();
108 Constant = tryTransformToIntOrEnumConstant(B->getLHS());
111 auto *D = dyn_cast<DeclRefExpr>(MaybeDecl->IgnoreParenImpCasts());
112 return std::make_tuple(D, Op, Constant);
115 /// For an expression `x == Foo && x == Bar`, this determines whether the
116 /// `Foo` and `Bar` are either of the same enumeration type, or both integer
119 /// It's an error to pass this arguments that are not either IntegerLiterals
120 /// or DeclRefExprs (that have decls of type EnumConstantDecl)
121 static bool areExprTypesCompatible(const Expr *E1, const Expr *E2) {
122 // User intent isn't clear if they're mixing int literals with enum
124 if (isa<IntegerLiteral>(E1) != isa<IntegerLiteral>(E2))
127 // Integer literal comparisons, regardless of literal type, are acceptable.
128 if (isa<IntegerLiteral>(E1))
131 // IntegerLiterals are handled above and only EnumConstantDecls are expected
133 assert(isa<DeclRefExpr>(E1) && isa<DeclRefExpr>(E2));
134 auto *Decl1 = cast<DeclRefExpr>(E1)->getDecl();
135 auto *Decl2 = cast<DeclRefExpr>(E2)->getDecl();
137 assert(isa<EnumConstantDecl>(Decl1) && isa<EnumConstantDecl>(Decl2));
138 const DeclContext *DC1 = Decl1->getDeclContext();
139 const DeclContext *DC2 = Decl2->getDeclContext();
141 assert(isa<EnumDecl>(DC1) && isa<EnumDecl>(DC2));
149 /// The CFG builder uses a recursive algorithm to build the CFG. When
150 /// we process an expression, sometimes we know that we must add the
151 /// subexpressions as block-level expressions. For example:
155 /// When processing the '||' expression, we know that exp1 and exp2
156 /// need to be added as block-level expressions, even though they
157 /// might not normally need to be. AddStmtChoice records this
158 /// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then
159 /// the builder has an option not to add a subexpression as a
160 /// block-level expression.
161 class AddStmtChoice {
163 enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 };
165 AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {}
167 bool alwaysAdd(CFGBuilder &builder,
168 const Stmt *stmt) const;
170 /// Return a copy of this object, except with the 'always-add' bit
171 /// set as specified.
172 AddStmtChoice withAlwaysAdd(bool alwaysAdd) const {
173 return AddStmtChoice(alwaysAdd ? AlwaysAdd : NotAlwaysAdd);
180 /// LocalScope - Node in tree of local scopes created for C++ implicit
181 /// destructor calls generation. It contains list of automatic variables
182 /// declared in the scope and link to position in previous scope this scope
185 /// The process of creating local scopes is as follows:
186 /// - Init CFGBuilder::ScopePos with invalid position (equivalent for null),
187 /// - Before processing statements in scope (e.g. CompoundStmt) create
188 /// LocalScope object using CFGBuilder::ScopePos as link to previous scope
189 /// and set CFGBuilder::ScopePos to the end of new scope,
190 /// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points
192 /// - For every normal (without jump) end of scope add to CFGBlock destructors
193 /// for objects in the current scope,
194 /// - For every jump add to CFGBlock destructors for objects
195 /// between CFGBuilder::ScopePos and local scope position saved for jump
196 /// target. Thanks to C++ restrictions on goto jumps we can be sure that
197 /// jump target position will be on the path to root from CFGBuilder::ScopePos
198 /// (adding any variable that doesn't need constructor to be called to
199 /// LocalScope can break this assumption),
203 friend class const_iterator;
205 using AutomaticVarsTy = BumpVector<VarDecl *>;
207 /// const_iterator - Iterates local scope backwards and jumps to previous
208 /// scope on reaching the beginning of currently iterated scope.
209 class const_iterator {
210 const LocalScope* Scope = nullptr;
212 /// VarIter is guaranteed to be greater then 0 for every valid iterator.
213 /// Invalid iterator (with null Scope) has VarIter equal to 0.
214 unsigned VarIter = 0;
217 /// Create invalid iterator. Dereferencing invalid iterator is not allowed.
218 /// Incrementing invalid iterator is allowed and will result in invalid
220 const_iterator() = default;
222 /// Create valid iterator. In case when S.Prev is an invalid iterator and
223 /// I is equal to 0, this will create invalid iterator.
224 const_iterator(const LocalScope& S, unsigned I)
225 : Scope(&S), VarIter(I) {
226 // Iterator to "end" of scope is not allowed. Handle it by going up
227 // in scopes tree possibly up to invalid iterator in the root.
228 if (VarIter == 0 && Scope)
232 VarDecl *const* operator->() const {
233 assert(Scope && "Dereferencing invalid iterator is not allowed");
234 assert(VarIter != 0 && "Iterator has invalid value of VarIter member");
235 return &Scope->Vars[VarIter - 1];
238 const VarDecl *getFirstVarInScope() const {
239 assert(Scope && "Dereferencing invalid iterator is not allowed");
240 assert(VarIter != 0 && "Iterator has invalid value of VarIter member");
241 return Scope->Vars[0];
244 VarDecl *operator*() const {
245 return *this->operator->();
248 const_iterator &operator++() {
252 assert(VarIter != 0 && "Iterator has invalid value of VarIter member");
258 const_iterator operator++(int) {
259 const_iterator P = *this;
264 bool operator==(const const_iterator &rhs) const {
265 return Scope == rhs.Scope && VarIter == rhs.VarIter;
267 bool operator!=(const const_iterator &rhs) const {
268 return !(*this == rhs);
271 explicit operator bool() const {
272 return *this != const_iterator();
275 int distance(const_iterator L);
276 const_iterator shared_parent(const_iterator L);
277 bool pointsToFirstDeclaredVar() { return VarIter == 1; }
281 BumpVectorContext ctx;
283 /// Automatic variables in order of declaration.
284 AutomaticVarsTy Vars;
286 /// Iterator to variable in previous scope that was declared just before
287 /// begin of this scope.
291 /// Constructs empty scope linked to previous scope in specified place.
292 LocalScope(BumpVectorContext ctx, const_iterator P)
293 : ctx(std::move(ctx)), Vars(this->ctx, 4), Prev(P) {}
295 /// Begin of scope in direction of CFG building (backwards).
296 const_iterator begin() const { return const_iterator(*this, Vars.size()); }
298 void addVar(VarDecl *VD) {
299 Vars.push_back(VD, ctx);
305 /// distance - Calculates distance from this to L. L must be reachable from this
306 /// (with use of ++ operator). Cost of calculating the distance is linear w.r.t.
307 /// number of scopes between this and L.
308 int LocalScope::const_iterator::distance(LocalScope::const_iterator L) {
310 const_iterator F = *this;
311 while (F.Scope != L.Scope) {
312 assert(F != const_iterator() &&
313 "L iterator is not reachable from F iterator.");
317 D += F.VarIter - L.VarIter;
321 /// Calculates the closest parent of this iterator
322 /// that is in a scope reachable through the parents of L.
323 /// I.e. when using 'goto' from this to L, the lifetime of all variables
324 /// between this and shared_parent(L) end.
325 LocalScope::const_iterator
326 LocalScope::const_iterator::shared_parent(LocalScope::const_iterator L) {
327 llvm::SmallPtrSet<const LocalScope *, 4> ScopesOfL;
329 ScopesOfL.insert(L.Scope);
330 if (L == const_iterator())
335 const_iterator F = *this;
337 if (ScopesOfL.count(F.Scope))
339 assert(F != const_iterator() &&
340 "L iterator is not reachable from F iterator.");
347 /// Structure for specifying position in CFG during its build process. It
348 /// consists of CFGBlock that specifies position in CFG and
349 /// LocalScope::const_iterator that specifies position in LocalScope graph.
350 struct BlockScopePosPair {
351 CFGBlock *block = nullptr;
352 LocalScope::const_iterator scopePosition;
354 BlockScopePosPair() = default;
355 BlockScopePosPair(CFGBlock *b, LocalScope::const_iterator scopePos)
356 : block(b), scopePosition(scopePos) {}
359 /// TryResult - a class representing a variant over the values
360 /// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool,
361 /// and is used by the CFGBuilder to decide if a branch condition
362 /// can be decided up front during CFG construction.
367 TryResult() = default;
368 TryResult(bool b) : X(b ? 1 : 0) {}
370 bool isTrue() const { return X == 1; }
371 bool isFalse() const { return X == 0; }
372 bool isKnown() const { return X >= 0; }
382 static TryResult bothKnownTrue(TryResult R1, TryResult R2) {
383 if (!R1.isKnown() || !R2.isKnown())
385 return TryResult(R1.isTrue() && R2.isTrue());
390 class reverse_children {
391 llvm::SmallVector<Stmt *, 12> childrenBuf;
392 ArrayRef<Stmt *> children;
395 reverse_children(Stmt *S);
397 using iterator = ArrayRef<Stmt *>::reverse_iterator;
399 iterator begin() const { return children.rbegin(); }
400 iterator end() const { return children.rend(); }
405 reverse_children::reverse_children(Stmt *S) {
406 if (CallExpr *CE = dyn_cast<CallExpr>(S)) {
407 children = CE->getRawSubExprs();
410 switch (S->getStmtClass()) {
411 // Note: Fill in this switch with more cases we want to optimize.
412 case Stmt::InitListExprClass: {
413 InitListExpr *IE = cast<InitListExpr>(S);
414 children = llvm::makeArrayRef(reinterpret_cast<Stmt**>(IE->getInits()),
422 // Default case for all other statements.
423 for (Stmt *SubStmt : S->children())
424 childrenBuf.push_back(SubStmt);
426 // This needs to be done *after* childrenBuf has been populated.
427 children = childrenBuf;
432 /// CFGBuilder - This class implements CFG construction from an AST.
433 /// The builder is stateful: an instance of the builder should be used to only
434 /// construct a single CFG.
438 /// CFGBuilder builder;
439 /// std::unique_ptr<CFG> cfg = builder.buildCFG(decl, stmt1);
441 /// CFG construction is done via a recursive walk of an AST. We actually parse
442 /// the AST in reverse order so that the successor of a basic block is
443 /// constructed prior to its predecessor. This allows us to nicely capture
444 /// implicit fall-throughs without extra basic blocks.
446 using JumpTarget = BlockScopePosPair;
447 using JumpSource = BlockScopePosPair;
450 std::unique_ptr<CFG> cfg;
453 CFGBlock *Block = nullptr;
455 // Block after the current block.
456 CFGBlock *Succ = nullptr;
458 JumpTarget ContinueJumpTarget;
459 JumpTarget BreakJumpTarget;
460 JumpTarget SEHLeaveJumpTarget;
461 CFGBlock *SwitchTerminatedBlock = nullptr;
462 CFGBlock *DefaultCaseBlock = nullptr;
464 // This can point either to a try or a __try block. The frontend forbids
465 // mixing both kinds in one function, so having one for both is enough.
466 CFGBlock *TryTerminatedBlock = nullptr;
468 // Current position in local scope.
469 LocalScope::const_iterator ScopePos;
471 // LabelMap records the mapping from Label expressions to their jump targets.
472 using LabelMapTy = llvm::DenseMap<LabelDecl *, JumpTarget>;
475 // A list of blocks that end with a "goto" that must be backpatched to their
476 // resolved targets upon completion of CFG construction.
477 using BackpatchBlocksTy = std::vector<JumpSource>;
478 BackpatchBlocksTy BackpatchBlocks;
480 // A list of labels whose address has been taken (for indirect gotos).
481 using LabelSetTy = llvm::SmallSetVector<LabelDecl *, 8>;
482 LabelSetTy AddressTakenLabels;
484 // Information about the currently visited C++ object construction site.
485 // This is set in the construction trigger and read when the constructor
486 // or a function that returns an object by value is being visited.
487 llvm::DenseMap<Expr *, const ConstructionContextLayer *>
488 ConstructionContextMap;
490 using DeclsWithEndedScopeSetTy = llvm::SmallSetVector<VarDecl *, 16>;
491 DeclsWithEndedScopeSetTy DeclsWithEndedScope;
494 const CFG::BuildOptions &BuildOpts;
496 // State to track for building switch statements.
497 bool switchExclusivelyCovered = false;
498 Expr::EvalResult *switchCond = nullptr;
500 CFG::BuildOptions::ForcedBlkExprs::value_type *cachedEntry = nullptr;
501 const Stmt *lastLookup = nullptr;
503 // Caches boolean evaluations of expressions to avoid multiple re-evaluations
504 // during construction of branches for chained logical operators.
505 using CachedBoolEvalsTy = llvm::DenseMap<Expr *, TryResult>;
506 CachedBoolEvalsTy CachedBoolEvals;
509 explicit CFGBuilder(ASTContext *astContext,
510 const CFG::BuildOptions &buildOpts)
511 : Context(astContext), cfg(new CFG()), // crew a new CFG
512 ConstructionContextMap(), BuildOpts(buildOpts) {}
515 // buildCFG - Used by external clients to construct the CFG.
516 std::unique_ptr<CFG> buildCFG(const Decl *D, Stmt *Statement);
518 bool alwaysAdd(const Stmt *stmt);
521 // Visitors to walk an AST and construct the CFG.
522 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc);
523 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc);
524 CFGBlock *VisitBreakStmt(BreakStmt *B);
525 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc);
526 CFGBlock *VisitCaseStmt(CaseStmt *C);
527 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc);
528 CFGBlock *VisitCompoundStmt(CompoundStmt *C);
529 CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C,
531 CFGBlock *VisitContinueStmt(ContinueStmt *C);
532 CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
534 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S);
535 CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc);
536 CFGBlock *VisitCXXNewExpr(CXXNewExpr *DE, AddStmtChoice asc);
537 CFGBlock *VisitCXXDeleteExpr(CXXDeleteExpr *DE, AddStmtChoice asc);
538 CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S);
539 CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
541 CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
543 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T);
544 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S);
545 CFGBlock *VisitDeclStmt(DeclStmt *DS);
546 CFGBlock *VisitDeclSubExpr(DeclStmt *DS);
547 CFGBlock *VisitDefaultStmt(DefaultStmt *D);
548 CFGBlock *VisitDoStmt(DoStmt *D);
549 CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, AddStmtChoice asc);
550 CFGBlock *VisitForStmt(ForStmt *F);
551 CFGBlock *VisitGotoStmt(GotoStmt *G);
552 CFGBlock *VisitIfStmt(IfStmt *I);
553 CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc);
554 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I);
555 CFGBlock *VisitLabelStmt(LabelStmt *L);
556 CFGBlock *VisitBlockExpr(BlockExpr *E, AddStmtChoice asc);
557 CFGBlock *VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc);
558 CFGBlock *VisitLogicalOperator(BinaryOperator *B);
559 std::pair<CFGBlock *, CFGBlock *> VisitLogicalOperator(BinaryOperator *B,
562 CFGBlock *FalseBlock);
563 CFGBlock *VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *MTE,
565 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc);
566 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S);
567 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S);
568 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S);
569 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S);
570 CFGBlock *VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S);
571 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S);
572 CFGBlock *VisitObjCMessageExpr(ObjCMessageExpr *E, AddStmtChoice asc);
573 CFGBlock *VisitPseudoObjectExpr(PseudoObjectExpr *E);
574 CFGBlock *VisitReturnStmt(ReturnStmt *R);
575 CFGBlock *VisitSEHExceptStmt(SEHExceptStmt *S);
576 CFGBlock *VisitSEHFinallyStmt(SEHFinallyStmt *S);
577 CFGBlock *VisitSEHLeaveStmt(SEHLeaveStmt *S);
578 CFGBlock *VisitSEHTryStmt(SEHTryStmt *S);
579 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc);
580 CFGBlock *VisitSwitchStmt(SwitchStmt *S);
581 CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
583 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc);
584 CFGBlock *VisitWhileStmt(WhileStmt *W);
586 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd);
587 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc);
588 CFGBlock *VisitChildren(Stmt *S);
589 CFGBlock *VisitNoRecurse(Expr *E, AddStmtChoice asc);
591 void maybeAddScopeBeginForVarDecl(CFGBlock *B, const VarDecl *VD,
593 if (ScopePos && (VD == ScopePos.getFirstVarInScope()))
594 appendScopeBegin(B, VD, S);
597 /// When creating the CFG for temporary destructors, we want to mirror the
598 /// branch structure of the corresponding constructor calls.
599 /// Thus, while visiting a statement for temporary destructors, we keep a
600 /// context to keep track of the following information:
601 /// - whether a subexpression is executed unconditionally
602 /// - if a subexpression is executed conditionally, the first
603 /// CXXBindTemporaryExpr we encounter in that subexpression (which
604 /// corresponds to the last temporary destructor we have to call for this
605 /// subexpression) and the CFG block at that point (which will become the
606 /// successor block when inserting the decision point).
608 /// That way, we can build the branch structure for temporary destructors as
610 /// 1. If a subexpression is executed unconditionally, we add the temporary
611 /// destructor calls to the current block.
612 /// 2. If a subexpression is executed conditionally, when we encounter a
613 /// CXXBindTemporaryExpr:
614 /// a) If it is the first temporary destructor call in the subexpression,
615 /// we remember the CXXBindTemporaryExpr and the current block in the
616 /// TempDtorContext; we start a new block, and insert the temporary
618 /// b) Otherwise, add the temporary destructor call to the current block.
619 /// 3. When we finished visiting a conditionally executed subexpression,
620 /// and we found at least one temporary constructor during the visitation
621 /// (2.a has executed), we insert a decision block that uses the
622 /// CXXBindTemporaryExpr as terminator, and branches to the current block
623 /// if the CXXBindTemporaryExpr was marked executed, and otherwise
624 /// branches to the stored successor.
625 struct TempDtorContext {
626 TempDtorContext() = default;
627 TempDtorContext(TryResult KnownExecuted)
628 : IsConditional(true), KnownExecuted(KnownExecuted) {}
630 /// Returns whether we need to start a new branch for a temporary destructor
631 /// call. This is the case when the temporary destructor is
632 /// conditionally executed, and it is the first one we encounter while
633 /// visiting a subexpression - other temporary destructors at the same level
634 /// will be added to the same block and are executed under the same
636 bool needsTempDtorBranch() const {
637 return IsConditional && !TerminatorExpr;
640 /// Remember the successor S of a temporary destructor decision branch for
641 /// the corresponding CXXBindTemporaryExpr E.
642 void setDecisionPoint(CFGBlock *S, CXXBindTemporaryExpr *E) {
647 const bool IsConditional = false;
648 const TryResult KnownExecuted = true;
649 CFGBlock *Succ = nullptr;
650 CXXBindTemporaryExpr *TerminatorExpr = nullptr;
653 // Visitors to walk an AST and generate destructors of temporaries in
655 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary,
656 TempDtorContext &Context);
657 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E, TempDtorContext &Context);
658 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E,
659 TempDtorContext &Context);
660 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(
661 CXXBindTemporaryExpr *E, bool BindToTemporary, TempDtorContext &Context);
662 CFGBlock *VisitConditionalOperatorForTemporaryDtors(
663 AbstractConditionalOperator *E, bool BindToTemporary,
664 TempDtorContext &Context);
665 void InsertTempDtorDecisionBlock(const TempDtorContext &Context,
666 CFGBlock *FalseSucc = nullptr);
668 // NYS == Not Yet Supported
674 // Remember to apply the construction context based on the current \p Layer
675 // when constructing the CFG element for \p CE.
676 void consumeConstructionContext(const ConstructionContextLayer *Layer,
679 // Scan \p Child statement to find constructors in it, while keeping in mind
680 // that its parent statement is providing a partial construction context
681 // described by \p Layer. If a constructor is found, it would be assigned
682 // the context based on the layer. If an additional construction context layer
683 // is found, the function recurses into that.
684 void findConstructionContexts(const ConstructionContextLayer *Layer,
687 // Scan all arguments of a call expression for a construction context.
688 // These sorts of call expressions don't have a common superclass,
689 // hence strict duck-typing.
690 template <typename CallLikeExpr,
691 typename = typename std::enable_if<
692 std::is_same<CallLikeExpr, CallExpr>::value ||
693 std::is_same<CallLikeExpr, CXXConstructExpr>::value ||
694 std::is_same<CallLikeExpr, ObjCMessageExpr>::value>>
695 void findConstructionContextsForArguments(CallLikeExpr *E) {
696 for (unsigned i = 0, e = E->getNumArgs(); i != e; ++i) {
697 Expr *Arg = E->getArg(i);
698 if (Arg->getType()->getAsCXXRecordDecl() && !Arg->isGLValue())
699 findConstructionContexts(
700 ConstructionContextLayer::create(cfg->getBumpVectorContext(),
701 ConstructionContextItem(E, i)),
706 // Unset the construction context after consuming it. This is done immediately
707 // after adding the CFGConstructor or CFGCXXRecordTypedCall element, so
708 // there's no need to do this manually in every Visit... function.
709 void cleanupConstructionContext(Expr *E);
711 void autoCreateBlock() { if (!Block) Block = createBlock(); }
712 CFGBlock *createBlock(bool add_successor = true);
713 CFGBlock *createNoReturnBlock();
715 CFGBlock *addStmt(Stmt *S) {
716 return Visit(S, AddStmtChoice::AlwaysAdd);
719 CFGBlock *addInitializer(CXXCtorInitializer *I);
720 void addLoopExit(const Stmt *LoopStmt);
721 void addAutomaticObjDtors(LocalScope::const_iterator B,
722 LocalScope::const_iterator E, Stmt *S);
723 void addLifetimeEnds(LocalScope::const_iterator B,
724 LocalScope::const_iterator E, Stmt *S);
725 void addAutomaticObjHandling(LocalScope::const_iterator B,
726 LocalScope::const_iterator E, Stmt *S);
727 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD);
728 void addScopesEnd(LocalScope::const_iterator B, LocalScope::const_iterator E,
731 void getDeclsWithEndedScope(LocalScope::const_iterator B,
732 LocalScope::const_iterator E, Stmt *S);
734 // Local scopes creation.
735 LocalScope* createOrReuseLocalScope(LocalScope* Scope);
737 void addLocalScopeForStmt(Stmt *S);
738 LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS,
739 LocalScope* Scope = nullptr);
740 LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = nullptr);
742 void addLocalScopeAndDtors(Stmt *S);
744 const ConstructionContext *retrieveAndCleanupConstructionContext(Expr *E) {
745 if (!BuildOpts.AddRichCXXConstructors)
748 const ConstructionContextLayer *Layer = ConstructionContextMap.lookup(E);
752 cleanupConstructionContext(E);
753 return ConstructionContext::createFromLayers(cfg->getBumpVectorContext(),
757 // Interface to CFGBlock - adding CFGElements.
759 void appendStmt(CFGBlock *B, const Stmt *S) {
760 if (alwaysAdd(S) && cachedEntry)
761 cachedEntry->second = B;
763 // All block-level expressions should have already been IgnoreParens()ed.
764 assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S);
765 B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext());
768 void appendConstructor(CFGBlock *B, CXXConstructExpr *CE) {
769 if (const ConstructionContext *CC =
770 retrieveAndCleanupConstructionContext(CE)) {
771 B->appendConstructor(CE, CC, cfg->getBumpVectorContext());
775 // No valid construction context found. Fall back to statement.
776 B->appendStmt(CE, cfg->getBumpVectorContext());
779 void appendCall(CFGBlock *B, CallExpr *CE) {
780 if (alwaysAdd(CE) && cachedEntry)
781 cachedEntry->second = B;
783 if (const ConstructionContext *CC =
784 retrieveAndCleanupConstructionContext(CE)) {
785 B->appendCXXRecordTypedCall(CE, CC, cfg->getBumpVectorContext());
789 // No valid construction context found. Fall back to statement.
790 B->appendStmt(CE, cfg->getBumpVectorContext());
793 void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) {
794 B->appendInitializer(I, cfg->getBumpVectorContext());
797 void appendNewAllocator(CFGBlock *B, CXXNewExpr *NE) {
798 B->appendNewAllocator(NE, cfg->getBumpVectorContext());
801 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) {
802 B->appendBaseDtor(BS, cfg->getBumpVectorContext());
805 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) {
806 B->appendMemberDtor(FD, cfg->getBumpVectorContext());
809 void appendObjCMessage(CFGBlock *B, ObjCMessageExpr *ME) {
810 if (alwaysAdd(ME) && cachedEntry)
811 cachedEntry->second = B;
813 if (const ConstructionContext *CC =
814 retrieveAndCleanupConstructionContext(ME)) {
815 B->appendCXXRecordTypedCall(ME, CC, cfg->getBumpVectorContext());
819 B->appendStmt(const_cast<ObjCMessageExpr *>(ME),
820 cfg->getBumpVectorContext());
823 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) {
824 B->appendTemporaryDtor(E, cfg->getBumpVectorContext());
827 void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) {
828 B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext());
831 void appendLifetimeEnds(CFGBlock *B, VarDecl *VD, Stmt *S) {
832 B->appendLifetimeEnds(VD, S, cfg->getBumpVectorContext());
835 void appendLoopExit(CFGBlock *B, const Stmt *LoopStmt) {
836 B->appendLoopExit(LoopStmt, cfg->getBumpVectorContext());
839 void appendDeleteDtor(CFGBlock *B, CXXRecordDecl *RD, CXXDeleteExpr *DE) {
840 B->appendDeleteDtor(RD, DE, cfg->getBumpVectorContext());
843 void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
844 LocalScope::const_iterator B, LocalScope::const_iterator E);
846 void prependAutomaticObjLifetimeWithTerminator(CFGBlock *Blk,
847 LocalScope::const_iterator B,
848 LocalScope::const_iterator E);
851 prependAutomaticObjScopeEndWithTerminator(CFGBlock *Blk,
852 LocalScope::const_iterator B,
853 LocalScope::const_iterator E);
855 void addSuccessor(CFGBlock *B, CFGBlock *S, bool IsReachable = true) {
856 B->addSuccessor(CFGBlock::AdjacentBlock(S, IsReachable),
857 cfg->getBumpVectorContext());
860 /// Add a reachable successor to a block, with the alternate variant that is
862 void addSuccessor(CFGBlock *B, CFGBlock *ReachableBlock, CFGBlock *AltBlock) {
863 B->addSuccessor(CFGBlock::AdjacentBlock(ReachableBlock, AltBlock),
864 cfg->getBumpVectorContext());
867 void appendScopeBegin(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
868 if (BuildOpts.AddScopes)
869 B->appendScopeBegin(VD, S, cfg->getBumpVectorContext());
872 void prependScopeBegin(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
873 if (BuildOpts.AddScopes)
874 B->prependScopeBegin(VD, S, cfg->getBumpVectorContext());
877 void appendScopeEnd(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
878 if (BuildOpts.AddScopes)
879 B->appendScopeEnd(VD, S, cfg->getBumpVectorContext());
882 void prependScopeEnd(CFGBlock *B, const VarDecl *VD, const Stmt *S) {
883 if (BuildOpts.AddScopes)
884 B->prependScopeEnd(VD, S, cfg->getBumpVectorContext());
887 /// Find a relational comparison with an expression evaluating to a
888 /// boolean and a constant other than 0 and 1.
889 /// e.g. if ((x < y) == 10)
890 TryResult checkIncorrectRelationalOperator(const BinaryOperator *B) {
891 const Expr *LHSExpr = B->getLHS()->IgnoreParens();
892 const Expr *RHSExpr = B->getRHS()->IgnoreParens();
894 const IntegerLiteral *IntLiteral = dyn_cast<IntegerLiteral>(LHSExpr);
895 const Expr *BoolExpr = RHSExpr;
896 bool IntFirst = true;
898 IntLiteral = dyn_cast<IntegerLiteral>(RHSExpr);
903 if (!IntLiteral || !BoolExpr->isKnownToHaveBooleanValue())
906 llvm::APInt IntValue = IntLiteral->getValue();
907 if ((IntValue == 1) || (IntValue == 0))
910 bool IntLarger = IntLiteral->getType()->isUnsignedIntegerType() ||
911 !IntValue.isNegative();
913 BinaryOperatorKind Bok = B->getOpcode();
914 if (Bok == BO_GT || Bok == BO_GE) {
915 // Always true for 10 > bool and bool > -1
916 // Always false for -1 > bool and bool > 10
917 return TryResult(IntFirst == IntLarger);
919 // Always true for -1 < bool and bool < 10
920 // Always false for 10 < bool and bool < -1
921 return TryResult(IntFirst != IntLarger);
925 /// Find an incorrect equality comparison. Either with an expression
926 /// evaluating to a boolean and a constant other than 0 and 1.
927 /// e.g. if (!x == 10) or a bitwise and/or operation that always evaluates to
928 /// true/false e.q. (x & 8) == 4.
929 TryResult checkIncorrectEqualityOperator(const BinaryOperator *B) {
930 const Expr *LHSExpr = B->getLHS()->IgnoreParens();
931 const Expr *RHSExpr = B->getRHS()->IgnoreParens();
933 const IntegerLiteral *IntLiteral = dyn_cast<IntegerLiteral>(LHSExpr);
934 const Expr *BoolExpr = RHSExpr;
937 IntLiteral = dyn_cast<IntegerLiteral>(RHSExpr);
944 const BinaryOperator *BitOp = dyn_cast<BinaryOperator>(BoolExpr);
945 if (BitOp && (BitOp->getOpcode() == BO_And ||
946 BitOp->getOpcode() == BO_Or)) {
947 const Expr *LHSExpr2 = BitOp->getLHS()->IgnoreParens();
948 const Expr *RHSExpr2 = BitOp->getRHS()->IgnoreParens();
950 const IntegerLiteral *IntLiteral2 = dyn_cast<IntegerLiteral>(LHSExpr2);
953 IntLiteral2 = dyn_cast<IntegerLiteral>(RHSExpr2);
958 llvm::APInt L1 = IntLiteral->getValue();
959 llvm::APInt L2 = IntLiteral2->getValue();
960 if ((BitOp->getOpcode() == BO_And && (L2 & L1) != L1) ||
961 (BitOp->getOpcode() == BO_Or && (L2 | L1) != L1)) {
962 if (BuildOpts.Observer)
963 BuildOpts.Observer->compareBitwiseEquality(B,
964 B->getOpcode() != BO_EQ);
965 TryResult(B->getOpcode() != BO_EQ);
967 } else if (BoolExpr->isKnownToHaveBooleanValue()) {
968 llvm::APInt IntValue = IntLiteral->getValue();
969 if ((IntValue == 1) || (IntValue == 0)) {
972 return TryResult(B->getOpcode() != BO_EQ);
978 TryResult analyzeLogicOperatorCondition(BinaryOperatorKind Relation,
979 const llvm::APSInt &Value1,
980 const llvm::APSInt &Value2) {
981 assert(Value1.isSigned() == Value2.isSigned());
986 return TryResult(Value1 == Value2);
988 return TryResult(Value1 != Value2);
990 return TryResult(Value1 < Value2);
992 return TryResult(Value1 <= Value2);
994 return TryResult(Value1 > Value2);
996 return TryResult(Value1 >= Value2);
1000 /// Find a pair of comparison expressions with or without parentheses
1001 /// with a shared variable and constants and a logical operator between them
1002 /// that always evaluates to either true or false.
1003 /// e.g. if (x != 3 || x != 4)
1004 TryResult checkIncorrectLogicOperator(const BinaryOperator *B) {
1005 assert(B->isLogicalOp());
1006 const BinaryOperator *LHS =
1007 dyn_cast<BinaryOperator>(B->getLHS()->IgnoreParens());
1008 const BinaryOperator *RHS =
1009 dyn_cast<BinaryOperator>(B->getRHS()->IgnoreParens());
1013 if (!LHS->isComparisonOp() || !RHS->isComparisonOp())
1016 const DeclRefExpr *Decl1;
1018 BinaryOperatorKind BO1;
1019 std::tie(Decl1, BO1, Expr1) = tryNormalizeBinaryOperator(LHS);
1021 if (!Decl1 || !Expr1)
1024 const DeclRefExpr *Decl2;
1026 BinaryOperatorKind BO2;
1027 std::tie(Decl2, BO2, Expr2) = tryNormalizeBinaryOperator(RHS);
1029 if (!Decl2 || !Expr2)
1032 // Check that it is the same variable on both sides.
1033 if (Decl1->getDecl() != Decl2->getDecl())
1036 // Make sure the user's intent is clear (e.g. they're comparing against two
1037 // int literals, or two things from the same enum)
1038 if (!areExprTypesCompatible(Expr1, Expr2))
1041 llvm::APSInt L1, L2;
1043 if (!Expr1->EvaluateAsInt(L1, *Context) ||
1044 !Expr2->EvaluateAsInt(L2, *Context))
1047 // Can't compare signed with unsigned or with different bit width.
1048 if (L1.isSigned() != L2.isSigned() || L1.getBitWidth() != L2.getBitWidth())
1051 // Values that will be used to determine if result of logical
1052 // operator is always true/false
1053 const llvm::APSInt Values[] = {
1054 // Value less than both Value1 and Value2
1055 llvm::APSInt::getMinValue(L1.getBitWidth(), L1.isUnsigned()),
1058 // Value between Value1 and Value2
1059 ((L1 < L2) ? L1 : L2) + llvm::APSInt(llvm::APInt(L1.getBitWidth(), 1),
1063 // Value greater than both Value1 and Value2
1064 llvm::APSInt::getMaxValue(L1.getBitWidth(), L1.isUnsigned()),
1067 // Check whether expression is always true/false by evaluating the following
1068 // * variable x is less than the smallest literal.
1069 // * variable x is equal to the smallest literal.
1070 // * Variable x is between smallest and largest literal.
1071 // * Variable x is equal to the largest literal.
1072 // * Variable x is greater than largest literal.
1073 bool AlwaysTrue = true, AlwaysFalse = true;
1074 for (const llvm::APSInt &Value : Values) {
1075 TryResult Res1, Res2;
1076 Res1 = analyzeLogicOperatorCondition(BO1, Value, L1);
1077 Res2 = analyzeLogicOperatorCondition(BO2, Value, L2);
1079 if (!Res1.isKnown() || !Res2.isKnown())
1082 if (B->getOpcode() == BO_LAnd) {
1083 AlwaysTrue &= (Res1.isTrue() && Res2.isTrue());
1084 AlwaysFalse &= !(Res1.isTrue() && Res2.isTrue());
1086 AlwaysTrue &= (Res1.isTrue() || Res2.isTrue());
1087 AlwaysFalse &= !(Res1.isTrue() || Res2.isTrue());
1091 if (AlwaysTrue || AlwaysFalse) {
1092 if (BuildOpts.Observer)
1093 BuildOpts.Observer->compareAlwaysTrue(B, AlwaysTrue);
1094 return TryResult(AlwaysTrue);
1099 /// Try and evaluate an expression to an integer constant.
1100 bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) {
1101 if (!BuildOpts.PruneTriviallyFalseEdges)
1103 return !S->isTypeDependent() &&
1104 !S->isValueDependent() &&
1105 S->EvaluateAsRValue(outResult, *Context);
1108 /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1
1109 /// if we can evaluate to a known value, otherwise return -1.
1110 TryResult tryEvaluateBool(Expr *S) {
1111 if (!BuildOpts.PruneTriviallyFalseEdges ||
1112 S->isTypeDependent() || S->isValueDependent())
1115 if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(S)) {
1116 if (Bop->isLogicalOp()) {
1117 // Check the cache first.
1118 CachedBoolEvalsTy::iterator I = CachedBoolEvals.find(S);
1119 if (I != CachedBoolEvals.end())
1120 return I->second; // already in map;
1122 // Retrieve result at first, or the map might be updated.
1123 TryResult Result = evaluateAsBooleanConditionNoCache(S);
1124 CachedBoolEvals[S] = Result; // update or insert
1128 switch (Bop->getOpcode()) {
1130 // For 'x & 0' and 'x * 0', we can determine that
1131 // the value is always false.
1134 // If either operand is zero, we know the value
1136 llvm::APSInt IntVal;
1137 if (Bop->getLHS()->EvaluateAsInt(IntVal, *Context)) {
1138 if (!IntVal.getBoolValue()) {
1139 return TryResult(false);
1142 if (Bop->getRHS()->EvaluateAsInt(IntVal, *Context)) {
1143 if (!IntVal.getBoolValue()) {
1144 return TryResult(false);
1153 return evaluateAsBooleanConditionNoCache(S);
1156 /// Evaluate as boolean \param E without using the cache.
1157 TryResult evaluateAsBooleanConditionNoCache(Expr *E) {
1158 if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(E)) {
1159 if (Bop->isLogicalOp()) {
1160 TryResult LHS = tryEvaluateBool(Bop->getLHS());
1161 if (LHS.isKnown()) {
1162 // We were able to evaluate the LHS, see if we can get away with not
1163 // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
1164 if (LHS.isTrue() == (Bop->getOpcode() == BO_LOr))
1165 return LHS.isTrue();
1167 TryResult RHS = tryEvaluateBool(Bop->getRHS());
1168 if (RHS.isKnown()) {
1169 if (Bop->getOpcode() == BO_LOr)
1170 return LHS.isTrue() || RHS.isTrue();
1172 return LHS.isTrue() && RHS.isTrue();
1175 TryResult RHS = tryEvaluateBool(Bop->getRHS());
1176 if (RHS.isKnown()) {
1177 // We can't evaluate the LHS; however, sometimes the result
1178 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
1179 if (RHS.isTrue() == (Bop->getOpcode() == BO_LOr))
1180 return RHS.isTrue();
1182 TryResult BopRes = checkIncorrectLogicOperator(Bop);
1183 if (BopRes.isKnown())
1184 return BopRes.isTrue();
1189 } else if (Bop->isEqualityOp()) {
1190 TryResult BopRes = checkIncorrectEqualityOperator(Bop);
1191 if (BopRes.isKnown())
1192 return BopRes.isTrue();
1193 } else if (Bop->isRelationalOp()) {
1194 TryResult BopRes = checkIncorrectRelationalOperator(Bop);
1195 if (BopRes.isKnown())
1196 return BopRes.isTrue();
1201 if (E->EvaluateAsBooleanCondition(Result, *Context))
1207 bool hasTrivialDestructor(VarDecl *VD);
1212 inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder,
1213 const Stmt *stmt) const {
1214 return builder.alwaysAdd(stmt) || kind == AlwaysAdd;
1217 bool CFGBuilder::alwaysAdd(const Stmt *stmt) {
1218 bool shouldAdd = BuildOpts.alwaysAdd(stmt);
1220 if (!BuildOpts.forcedBlkExprs)
1223 if (lastLookup == stmt) {
1225 assert(cachedEntry->first == stmt);
1233 // Perform the lookup!
1234 CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs;
1237 // No need to update 'cachedEntry', since it will always be null.
1238 assert(!cachedEntry);
1242 CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt);
1243 if (itr == fb->end()) {
1244 cachedEntry = nullptr;
1248 cachedEntry = &*itr;
1252 // FIXME: Add support for dependent-sized array types in C++?
1253 // Does it even make sense to build a CFG for an uninstantiated template?
1254 static const VariableArrayType *FindVA(const Type *t) {
1255 while (const ArrayType *vt = dyn_cast<ArrayType>(t)) {
1256 if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt))
1257 if (vat->getSizeExpr())
1260 t = vt->getElementType().getTypePtr();
1266 void CFGBuilder::consumeConstructionContext(
1267 const ConstructionContextLayer *Layer, Expr *E) {
1268 assert((isa<CXXConstructExpr>(E) || isa<CallExpr>(E) ||
1269 isa<ObjCMessageExpr>(E)) && "Expression cannot construct an object!");
1270 if (const ConstructionContextLayer *PreviouslyStoredLayer =
1271 ConstructionContextMap.lookup(E)) {
1272 (void)PreviouslyStoredLayer;
1273 // We might have visited this child when we were finding construction
1274 // contexts within its parents.
1275 assert(PreviouslyStoredLayer->isStrictlyMoreSpecificThan(Layer) &&
1276 "Already within a different construction context!");
1278 ConstructionContextMap[E] = Layer;
1282 void CFGBuilder::findConstructionContexts(
1283 const ConstructionContextLayer *Layer, Stmt *Child) {
1284 if (!BuildOpts.AddRichCXXConstructors)
1290 auto withExtraLayer = [this, Layer](const ConstructionContextItem &Item) {
1291 return ConstructionContextLayer::create(cfg->getBumpVectorContext(), Item,
1295 switch(Child->getStmtClass()) {
1296 case Stmt::CXXConstructExprClass:
1297 case Stmt::CXXTemporaryObjectExprClass: {
1298 // Support pre-C++17 copy elision AST.
1299 auto *CE = cast<CXXConstructExpr>(Child);
1300 if (BuildOpts.MarkElidedCXXConstructors && CE->isElidable()) {
1301 findConstructionContexts(withExtraLayer(CE), CE->getArg(0));
1304 consumeConstructionContext(Layer, CE);
1307 // FIXME: This, like the main visit, doesn't support CUDAKernelCallExpr.
1308 // FIXME: An isa<> would look much better but this whole switch is a
1309 // workaround for an internal compiler error in MSVC 2015 (see r326021).
1310 case Stmt::CallExprClass:
1311 case Stmt::CXXMemberCallExprClass:
1312 case Stmt::CXXOperatorCallExprClass:
1313 case Stmt::UserDefinedLiteralClass:
1314 case Stmt::ObjCMessageExprClass: {
1315 auto *E = cast<Expr>(Child);
1316 if (CFGCXXRecordTypedCall::isCXXRecordTypedCall(E))
1317 consumeConstructionContext(Layer, E);
1320 case Stmt::ExprWithCleanupsClass: {
1321 auto *Cleanups = cast<ExprWithCleanups>(Child);
1322 findConstructionContexts(Layer, Cleanups->getSubExpr());
1325 case Stmt::CXXFunctionalCastExprClass: {
1326 auto *Cast = cast<CXXFunctionalCastExpr>(Child);
1327 findConstructionContexts(Layer, Cast->getSubExpr());
1330 case Stmt::ImplicitCastExprClass: {
1331 auto *Cast = cast<ImplicitCastExpr>(Child);
1332 // Should we support other implicit cast kinds?
1333 switch (Cast->getCastKind()) {
1335 case CK_ConstructorConversion:
1336 findConstructionContexts(Layer, Cast->getSubExpr());
1342 case Stmt::CXXBindTemporaryExprClass: {
1343 auto *BTE = cast<CXXBindTemporaryExpr>(Child);
1344 findConstructionContexts(withExtraLayer(BTE), BTE->getSubExpr());
1347 case Stmt::MaterializeTemporaryExprClass: {
1348 // Normally we don't want to search in MaterializeTemporaryExpr because
1349 // it indicates the beginning of a temporary object construction context,
1350 // so it shouldn't be found in the middle. However, if it is the beginning
1351 // of an elidable copy or move construction context, we need to include it.
1352 if (Layer->getItem().getKind() ==
1353 ConstructionContextItem::ElidableConstructorKind) {
1354 auto *MTE = cast<MaterializeTemporaryExpr>(Child);
1355 findConstructionContexts(withExtraLayer(MTE), MTE->GetTemporaryExpr());
1359 case Stmt::ConditionalOperatorClass: {
1360 auto *CO = cast<ConditionalOperator>(Child);
1361 if (Layer->getItem().getKind() !=
1362 ConstructionContextItem::MaterializationKind) {
1363 // If the object returned by the conditional operator is not going to be a
1364 // temporary object that needs to be immediately materialized, then
1365 // it must be C++17 with its mandatory copy elision. Do not yet promise
1366 // to support this case.
1367 assert(!CO->getType()->getAsCXXRecordDecl() || CO->isGLValue() ||
1368 Context->getLangOpts().CPlusPlus17);
1371 findConstructionContexts(Layer, CO->getLHS());
1372 findConstructionContexts(Layer, CO->getRHS());
1380 void CFGBuilder::cleanupConstructionContext(Expr *E) {
1381 assert(BuildOpts.AddRichCXXConstructors &&
1382 "We should not be managing construction contexts!");
1383 assert(ConstructionContextMap.count(E) &&
1384 "Cannot exit construction context without the context!");
1385 ConstructionContextMap.erase(E);
1389 /// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an
1390 /// arbitrary statement. Examples include a single expression or a function
1391 /// body (compound statement). The ownership of the returned CFG is
1392 /// transferred to the caller. If CFG construction fails, this method returns
1394 std::unique_ptr<CFG> CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) {
1399 // Create an empty block that will serve as the exit block for the CFG. Since
1400 // this is the first block added to the CFG, it will be implicitly registered
1401 // as the exit block.
1402 Succ = createBlock();
1403 assert(Succ == &cfg->getExit());
1404 Block = nullptr; // the EXIT block is empty. Create all other blocks lazily.
1406 assert(!(BuildOpts.AddImplicitDtors && BuildOpts.AddLifetime) &&
1407 "AddImplicitDtors and AddLifetime cannot be used at the same time");
1409 if (BuildOpts.AddImplicitDtors)
1410 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D))
1411 addImplicitDtorsForDestructor(DD);
1413 // Visit the statements and create the CFG.
1414 CFGBlock *B = addStmt(Statement);
1419 // For C++ constructor add initializers to CFG.
1420 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) {
1421 for (auto *I : llvm::reverse(CD->inits())) {
1422 B = addInitializer(I);
1431 // Backpatch the gotos whose label -> block mappings we didn't know when we
1432 // encountered them.
1433 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(),
1434 E = BackpatchBlocks.end(); I != E; ++I ) {
1436 CFGBlock *B = I->block;
1437 const GotoStmt *G = cast<GotoStmt>(B->getTerminator());
1438 LabelMapTy::iterator LI = LabelMap.find(G->getLabel());
1440 // If there is no target for the goto, then we are looking at an
1441 // incomplete AST. Handle this by not registering a successor.
1442 if (LI == LabelMap.end()) continue;
1444 JumpTarget JT = LI->second;
1445 prependAutomaticObjLifetimeWithTerminator(B, I->scopePosition,
1447 prependAutomaticObjDtorsWithTerminator(B, I->scopePosition,
1449 const VarDecl *VD = prependAutomaticObjScopeEndWithTerminator(
1450 B, I->scopePosition, JT.scopePosition);
1451 appendScopeBegin(JT.block, VD, G);
1452 addSuccessor(B, JT.block);
1455 // Add successors to the Indirect Goto Dispatch block (if we have one).
1456 if (CFGBlock *B = cfg->getIndirectGotoBlock())
1457 for (LabelSetTy::iterator I = AddressTakenLabels.begin(),
1458 E = AddressTakenLabels.end(); I != E; ++I ) {
1459 // Lookup the target block.
1460 LabelMapTy::iterator LI = LabelMap.find(*I);
1462 // If there is no target block that contains label, then we are looking
1463 // at an incomplete AST. Handle this by not registering a successor.
1464 if (LI == LabelMap.end()) continue;
1466 addSuccessor(B, LI->second.block);
1469 // Create an empty entry block that has no predecessors.
1470 cfg->setEntry(createBlock());
1472 if (BuildOpts.AddRichCXXConstructors)
1473 assert(ConstructionContextMap.empty() &&
1474 "Not all construction contexts were cleaned up!");
1476 return std::move(cfg);
1479 /// createBlock - Used to lazily create blocks that are connected
1480 /// to the current (global) succcessor.
1481 CFGBlock *CFGBuilder::createBlock(bool add_successor) {
1482 CFGBlock *B = cfg->createBlock();
1483 if (add_successor && Succ)
1484 addSuccessor(B, Succ);
1488 /// createNoReturnBlock - Used to create a block is a 'noreturn' point in the
1489 /// CFG. It is *not* connected to the current (global) successor, and instead
1490 /// directly tied to the exit block in order to be reachable.
1491 CFGBlock *CFGBuilder::createNoReturnBlock() {
1492 CFGBlock *B = createBlock(false);
1493 B->setHasNoReturnElement();
1494 addSuccessor(B, &cfg->getExit(), Succ);
1498 /// addInitializer - Add C++ base or member initializer element to CFG.
1499 CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) {
1500 if (!BuildOpts.AddInitializers)
1503 bool HasTemporaries = false;
1505 // Destructors of temporaries in initialization expression should be called
1506 // after initialization finishes.
1507 Expr *Init = I->getInit();
1509 HasTemporaries = isa<ExprWithCleanups>(Init);
1511 if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
1512 // Generate destructors for temporaries in initialization expression.
1513 TempDtorContext Context;
1514 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
1515 /*BindToTemporary=*/false, Context);
1520 appendInitializer(Block, I);
1523 findConstructionContexts(
1524 ConstructionContextLayer::create(cfg->getBumpVectorContext(), I),
1527 if (HasTemporaries) {
1528 // For expression with temporaries go directly to subexpression to omit
1529 // generating destructors for the second time.
1530 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr());
1532 if (BuildOpts.AddCXXDefaultInitExprInCtors) {
1533 if (CXXDefaultInitExpr *Default = dyn_cast<CXXDefaultInitExpr>(Init)) {
1534 // In general, appending the expression wrapped by a CXXDefaultInitExpr
1535 // may cause the same Expr to appear more than once in the CFG. Doing it
1536 // here is safe because there's only one initializer per field.
1538 appendStmt(Block, Default);
1539 if (Stmt *Child = Default->getExpr())
1540 if (CFGBlock *R = Visit(Child))
1551 /// Retrieve the type of the temporary object whose lifetime was
1552 /// extended by a local reference with the given initializer.
1553 static QualType getReferenceInitTemporaryType(const Expr *Init,
1554 bool *FoundMTE = nullptr) {
1556 // Skip parentheses.
1557 Init = Init->IgnoreParens();
1559 // Skip through cleanups.
1560 if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Init)) {
1561 Init = EWC->getSubExpr();
1565 // Skip through the temporary-materialization expression.
1566 if (const MaterializeTemporaryExpr *MTE
1567 = dyn_cast<MaterializeTemporaryExpr>(Init)) {
1568 Init = MTE->GetTemporaryExpr();
1574 // Skip sub-object accesses into rvalues.
1575 SmallVector<const Expr *, 2> CommaLHSs;
1576 SmallVector<SubobjectAdjustment, 2> Adjustments;
1577 const Expr *SkippedInit =
1578 Init->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
1579 if (SkippedInit != Init) {
1587 return Init->getType();
1590 // TODO: Support adding LoopExit element to the CFG in case where the loop is
1591 // ended by ReturnStmt, GotoStmt or ThrowExpr.
1592 void CFGBuilder::addLoopExit(const Stmt *LoopStmt){
1593 if(!BuildOpts.AddLoopExit)
1596 appendLoopExit(Block, LoopStmt);
1599 void CFGBuilder::getDeclsWithEndedScope(LocalScope::const_iterator B,
1600 LocalScope::const_iterator E, Stmt *S) {
1601 if (!BuildOpts.AddScopes)
1607 // To go from B to E, one first goes up the scopes from B to P
1608 // then sideways in one scope from P to P' and then down
1609 // the scopes from P' to E.
1610 // The lifetime of all objects between B and P end.
1611 LocalScope::const_iterator P = B.shared_parent(E);
1612 int Dist = B.distance(P);
1616 for (LocalScope::const_iterator I = B; I != P; ++I)
1617 if (I.pointsToFirstDeclaredVar())
1618 DeclsWithEndedScope.insert(*I);
1621 void CFGBuilder::addAutomaticObjHandling(LocalScope::const_iterator B,
1622 LocalScope::const_iterator E,
1624 getDeclsWithEndedScope(B, E, S);
1625 if (BuildOpts.AddScopes)
1626 addScopesEnd(B, E, S);
1627 if (BuildOpts.AddImplicitDtors)
1628 addAutomaticObjDtors(B, E, S);
1629 if (BuildOpts.AddLifetime)
1630 addLifetimeEnds(B, E, S);
1633 /// Add to current block automatic objects that leave the scope.
1634 void CFGBuilder::addLifetimeEnds(LocalScope::const_iterator B,
1635 LocalScope::const_iterator E, Stmt *S) {
1636 if (!BuildOpts.AddLifetime)
1642 // To go from B to E, one first goes up the scopes from B to P
1643 // then sideways in one scope from P to P' and then down
1644 // the scopes from P' to E.
1645 // The lifetime of all objects between B and P end.
1646 LocalScope::const_iterator P = B.shared_parent(E);
1647 int dist = B.distance(P);
1651 // We need to perform the scope leaving in reverse order
1652 SmallVector<VarDecl *, 10> DeclsTrivial;
1653 SmallVector<VarDecl *, 10> DeclsNonTrivial;
1654 DeclsTrivial.reserve(dist);
1655 DeclsNonTrivial.reserve(dist);
1657 for (LocalScope::const_iterator I = B; I != P; ++I)
1658 if (hasTrivialDestructor(*I))
1659 DeclsTrivial.push_back(*I);
1661 DeclsNonTrivial.push_back(*I);
1664 // object with trivial destructor end their lifetime last (when storage
1666 for (SmallVectorImpl<VarDecl *>::reverse_iterator I = DeclsTrivial.rbegin(),
1667 E = DeclsTrivial.rend();
1669 appendLifetimeEnds(Block, *I, S);
1671 for (SmallVectorImpl<VarDecl *>::reverse_iterator
1672 I = DeclsNonTrivial.rbegin(),
1673 E = DeclsNonTrivial.rend();
1675 appendLifetimeEnds(Block, *I, S);
1678 /// Add to current block markers for ending scopes.
1679 void CFGBuilder::addScopesEnd(LocalScope::const_iterator B,
1680 LocalScope::const_iterator E, Stmt *S) {
1681 // If implicit destructors are enabled, we'll add scope ends in
1682 // addAutomaticObjDtors.
1683 if (BuildOpts.AddImplicitDtors)
1688 for (auto I = DeclsWithEndedScope.rbegin(), E = DeclsWithEndedScope.rend();
1690 appendScopeEnd(Block, *I, S);
1695 /// addAutomaticObjDtors - Add to current block automatic objects destructors
1696 /// for objects in range of local scope positions. Use S as trigger statement
1697 /// for destructors.
1698 void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B,
1699 LocalScope::const_iterator E, Stmt *S) {
1700 if (!BuildOpts.AddImplicitDtors)
1706 // We need to append the destructors in reverse order, but any one of them
1707 // may be a no-return destructor which changes the CFG. As a result, buffer
1708 // this sequence up and replay them in reverse order when appending onto the
1710 SmallVector<VarDecl*, 10> Decls;
1711 Decls.reserve(B.distance(E));
1712 for (LocalScope::const_iterator I = B; I != E; ++I)
1713 Decls.push_back(*I);
1715 for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(),
1718 if (hasTrivialDestructor(*I)) {
1719 // If AddScopes is enabled and *I is a first variable in a scope, add a
1720 // ScopeEnd marker in a Block.
1721 if (BuildOpts.AddScopes && DeclsWithEndedScope.count(*I)) {
1723 appendScopeEnd(Block, *I, S);
1727 // If this destructor is marked as a no-return destructor, we need to
1728 // create a new block for the destructor which does not have as a successor
1729 // anything built thus far: control won't flow out of this block.
1730 QualType Ty = (*I)->getType();
1731 if (Ty->isReferenceType()) {
1732 Ty = getReferenceInitTemporaryType((*I)->getInit());
1734 Ty = Context->getBaseElementType(Ty);
1736 if (Ty->getAsCXXRecordDecl()->isAnyDestructorNoReturn())
1737 Block = createNoReturnBlock();
1741 // Add ScopeEnd just after automatic obj destructor.
1742 if (BuildOpts.AddScopes && DeclsWithEndedScope.count(*I))
1743 appendScopeEnd(Block, *I, S);
1744 appendAutomaticObjDtor(Block, *I, S);
1748 /// addImplicitDtorsForDestructor - Add implicit destructors generated for
1749 /// base and member objects in destructor.
1750 void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) {
1751 assert(BuildOpts.AddImplicitDtors &&
1752 "Can be called only when dtors should be added");
1753 const CXXRecordDecl *RD = DD->getParent();
1755 // At the end destroy virtual base objects.
1756 for (const auto &VI : RD->vbases()) {
1757 const CXXRecordDecl *CD = VI.getType()->getAsCXXRecordDecl();
1758 if (!CD->hasTrivialDestructor()) {
1760 appendBaseDtor(Block, &VI);
1764 // Before virtual bases destroy direct base objects.
1765 for (const auto &BI : RD->bases()) {
1766 if (!BI.isVirtual()) {
1767 const CXXRecordDecl *CD = BI.getType()->getAsCXXRecordDecl();
1768 if (!CD->hasTrivialDestructor()) {
1770 appendBaseDtor(Block, &BI);
1775 // First destroy member objects.
1776 for (auto *FI : RD->fields()) {
1777 // Check for constant size array. Set type to array element type.
1778 QualType QT = FI->getType();
1779 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
1780 if (AT->getSize() == 0)
1782 QT = AT->getElementType();
1785 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
1786 if (!CD->hasTrivialDestructor()) {
1788 appendMemberDtor(Block, FI);
1793 /// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either
1794 /// way return valid LocalScope object.
1795 LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) {
1798 llvm::BumpPtrAllocator &alloc = cfg->getAllocator();
1799 return new (alloc.Allocate<LocalScope>())
1800 LocalScope(BumpVectorContext(alloc), ScopePos);
1803 /// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement
1804 /// that should create implicit scope (e.g. if/else substatements).
1805 void CFGBuilder::addLocalScopeForStmt(Stmt *S) {
1806 if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1807 !BuildOpts.AddScopes)
1810 LocalScope *Scope = nullptr;
1812 // For compound statement we will be creating explicit scope.
1813 if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
1814 for (auto *BI : CS->body()) {
1815 Stmt *SI = BI->stripLabelLikeStatements();
1816 if (DeclStmt *DS = dyn_cast<DeclStmt>(SI))
1817 Scope = addLocalScopeForDeclStmt(DS, Scope);
1822 // For any other statement scope will be implicit and as such will be
1823 // interesting only for DeclStmt.
1824 if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements()))
1825 addLocalScopeForDeclStmt(DS);
1828 /// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will
1829 /// reuse Scope if not NULL.
1830 LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS,
1831 LocalScope* Scope) {
1832 if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1833 !BuildOpts.AddScopes)
1836 for (auto *DI : DS->decls())
1837 if (VarDecl *VD = dyn_cast<VarDecl>(DI))
1838 Scope = addLocalScopeForVarDecl(VD, Scope);
1842 bool CFGBuilder::hasTrivialDestructor(VarDecl *VD) {
1843 // Check for const references bound to temporary. Set type to pointee.
1844 QualType QT = VD->getType();
1845 if (QT->isReferenceType()) {
1846 // Attempt to determine whether this declaration lifetime-extends a
1849 // FIXME: This is incorrect. Non-reference declarations can lifetime-extend
1850 // temporaries, and a single declaration can extend multiple temporaries.
1851 // We should look at the storage duration on each nested
1852 // MaterializeTemporaryExpr instead.
1854 const Expr *Init = VD->getInit();
1856 // Probably an exception catch-by-reference variable.
1857 // FIXME: It doesn't really mean that the object has a trivial destructor.
1858 // Also are there other cases?
1862 // Lifetime-extending a temporary?
1863 bool FoundMTE = false;
1864 QT = getReferenceInitTemporaryType(Init, &FoundMTE);
1869 // Check for constant size array. Set type to array element type.
1870 while (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
1871 if (AT->getSize() == 0)
1873 QT = AT->getElementType();
1876 // Check if type is a C++ class with non-trivial destructor.
1877 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
1878 return !CD->hasDefinition() || CD->hasTrivialDestructor();
1882 /// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will
1883 /// create add scope for automatic objects and temporary objects bound to
1884 /// const reference. Will reuse Scope if not NULL.
1885 LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD,
1886 LocalScope* Scope) {
1887 assert(!(BuildOpts.AddImplicitDtors && BuildOpts.AddLifetime) &&
1888 "AddImplicitDtors and AddLifetime cannot be used at the same time");
1889 if (!BuildOpts.AddImplicitDtors && !BuildOpts.AddLifetime &&
1890 !BuildOpts.AddScopes)
1893 // Check if variable is local.
1894 switch (VD->getStorageClass()) {
1899 default: return Scope;
1902 if (BuildOpts.AddImplicitDtors) {
1903 if (!hasTrivialDestructor(VD) || BuildOpts.AddScopes) {
1904 // Add the variable to scope
1905 Scope = createOrReuseLocalScope(Scope);
1907 ScopePos = Scope->begin();
1912 assert(BuildOpts.AddLifetime);
1913 // Add the variable to scope
1914 Scope = createOrReuseLocalScope(Scope);
1916 ScopePos = Scope->begin();
1920 /// addLocalScopeAndDtors - For given statement add local scope for it and
1921 /// add destructors that will cleanup the scope. Will reuse Scope if not NULL.
1922 void CFGBuilder::addLocalScopeAndDtors(Stmt *S) {
1923 LocalScope::const_iterator scopeBeginPos = ScopePos;
1924 addLocalScopeForStmt(S);
1925 addAutomaticObjHandling(ScopePos, scopeBeginPos, S);
1928 /// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for
1929 /// variables with automatic storage duration to CFGBlock's elements vector.
1930 /// Elements will be prepended to physical beginning of the vector which
1931 /// happens to be logical end. Use blocks terminator as statement that specifies
1932 /// destructors call site.
1933 /// FIXME: This mechanism for adding automatic destructors doesn't handle
1934 /// no-return destructors properly.
1935 void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
1936 LocalScope::const_iterator B, LocalScope::const_iterator E) {
1937 if (!BuildOpts.AddImplicitDtors)
1939 BumpVectorContext &C = cfg->getBumpVectorContext();
1940 CFGBlock::iterator InsertPos
1941 = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C);
1942 for (LocalScope::const_iterator I = B; I != E; ++I)
1943 InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I,
1944 Blk->getTerminator());
1947 /// prependAutomaticObjLifetimeWithTerminator - Prepend lifetime CFGElements for
1948 /// variables with automatic storage duration to CFGBlock's elements vector.
1949 /// Elements will be prepended to physical beginning of the vector which
1950 /// happens to be logical end. Use blocks terminator as statement that specifies
1951 /// where lifetime ends.
1952 void CFGBuilder::prependAutomaticObjLifetimeWithTerminator(
1953 CFGBlock *Blk, LocalScope::const_iterator B, LocalScope::const_iterator E) {
1954 if (!BuildOpts.AddLifetime)
1956 BumpVectorContext &C = cfg->getBumpVectorContext();
1957 CFGBlock::iterator InsertPos =
1958 Blk->beginLifetimeEndsInsert(Blk->end(), B.distance(E), C);
1959 for (LocalScope::const_iterator I = B; I != E; ++I)
1960 InsertPos = Blk->insertLifetimeEnds(InsertPos, *I, Blk->getTerminator());
1963 /// prependAutomaticObjScopeEndWithTerminator - Prepend scope end CFGElements for
1964 /// variables with automatic storage duration to CFGBlock's elements vector.
1965 /// Elements will be prepended to physical beginning of the vector which
1966 /// happens to be logical end. Use blocks terminator as statement that specifies
1967 /// where scope ends.
1969 CFGBuilder::prependAutomaticObjScopeEndWithTerminator(
1970 CFGBlock *Blk, LocalScope::const_iterator B, LocalScope::const_iterator E) {
1971 if (!BuildOpts.AddScopes)
1973 BumpVectorContext &C = cfg->getBumpVectorContext();
1974 CFGBlock::iterator InsertPos =
1975 Blk->beginScopeEndInsert(Blk->end(), 1, C);
1976 LocalScope::const_iterator PlaceToInsert = B;
1977 for (LocalScope::const_iterator I = B; I != E; ++I)
1979 Blk->insertScopeEnd(InsertPos, *PlaceToInsert, Blk->getTerminator());
1980 return *PlaceToInsert;
1983 /// Visit - Walk the subtree of a statement and add extra
1984 /// blocks for ternary operators, &&, and ||. We also process "," and
1985 /// DeclStmts (which may contain nested control-flow).
1986 CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) {
1992 if (Expr *E = dyn_cast<Expr>(S))
1993 S = E->IgnoreParens();
1995 switch (S->getStmtClass()) {
1997 return VisitStmt(S, asc);
1999 case Stmt::AddrLabelExprClass:
2000 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc);
2002 case Stmt::BinaryConditionalOperatorClass:
2003 return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc);
2005 case Stmt::BinaryOperatorClass:
2006 return VisitBinaryOperator(cast<BinaryOperator>(S), asc);
2008 case Stmt::BlockExprClass:
2009 return VisitBlockExpr(cast<BlockExpr>(S), asc);
2011 case Stmt::BreakStmtClass:
2012 return VisitBreakStmt(cast<BreakStmt>(S));
2014 case Stmt::CallExprClass:
2015 case Stmt::CXXOperatorCallExprClass:
2016 case Stmt::CXXMemberCallExprClass:
2017 case Stmt::UserDefinedLiteralClass:
2018 return VisitCallExpr(cast<CallExpr>(S), asc);
2020 case Stmt::CaseStmtClass:
2021 return VisitCaseStmt(cast<CaseStmt>(S));
2023 case Stmt::ChooseExprClass:
2024 return VisitChooseExpr(cast<ChooseExpr>(S), asc);
2026 case Stmt::CompoundStmtClass:
2027 return VisitCompoundStmt(cast<CompoundStmt>(S));
2029 case Stmt::ConditionalOperatorClass:
2030 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc);
2032 case Stmt::ContinueStmtClass:
2033 return VisitContinueStmt(cast<ContinueStmt>(S));
2035 case Stmt::CXXCatchStmtClass:
2036 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S));
2038 case Stmt::ExprWithCleanupsClass:
2039 return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc);
2041 case Stmt::CXXDefaultArgExprClass:
2042 case Stmt::CXXDefaultInitExprClass:
2043 // FIXME: The expression inside a CXXDefaultArgExpr is owned by the
2044 // called function's declaration, not by the caller. If we simply add
2045 // this expression to the CFG, we could end up with the same Expr
2046 // appearing multiple times.
2047 // PR13385 / <rdar://problem/12156507>
2049 // It's likewise possible for multiple CXXDefaultInitExprs for the same
2050 // expression to be used in the same function (through aggregate
2052 return VisitStmt(S, asc);
2054 case Stmt::CXXBindTemporaryExprClass:
2055 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc);
2057 case Stmt::CXXConstructExprClass:
2058 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc);
2060 case Stmt::CXXNewExprClass:
2061 return VisitCXXNewExpr(cast<CXXNewExpr>(S), asc);
2063 case Stmt::CXXDeleteExprClass:
2064 return VisitCXXDeleteExpr(cast<CXXDeleteExpr>(S), asc);
2066 case Stmt::CXXFunctionalCastExprClass:
2067 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc);
2069 case Stmt::CXXTemporaryObjectExprClass:
2070 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc);
2072 case Stmt::CXXThrowExprClass:
2073 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S));
2075 case Stmt::CXXTryStmtClass:
2076 return VisitCXXTryStmt(cast<CXXTryStmt>(S));
2078 case Stmt::CXXForRangeStmtClass:
2079 return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S));
2081 case Stmt::DeclStmtClass:
2082 return VisitDeclStmt(cast<DeclStmt>(S));
2084 case Stmt::DefaultStmtClass:
2085 return VisitDefaultStmt(cast<DefaultStmt>(S));
2087 case Stmt::DoStmtClass:
2088 return VisitDoStmt(cast<DoStmt>(S));
2090 case Stmt::ForStmtClass:
2091 return VisitForStmt(cast<ForStmt>(S));
2093 case Stmt::GotoStmtClass:
2094 return VisitGotoStmt(cast<GotoStmt>(S));
2096 case Stmt::IfStmtClass:
2097 return VisitIfStmt(cast<IfStmt>(S));
2099 case Stmt::ImplicitCastExprClass:
2100 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc);
2102 case Stmt::IndirectGotoStmtClass:
2103 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S));
2105 case Stmt::LabelStmtClass:
2106 return VisitLabelStmt(cast<LabelStmt>(S));
2108 case Stmt::LambdaExprClass:
2109 return VisitLambdaExpr(cast<LambdaExpr>(S), asc);
2111 case Stmt::MaterializeTemporaryExprClass:
2112 return VisitMaterializeTemporaryExpr(cast<MaterializeTemporaryExpr>(S),
2115 case Stmt::MemberExprClass:
2116 return VisitMemberExpr(cast<MemberExpr>(S), asc);
2118 case Stmt::NullStmtClass:
2121 case Stmt::ObjCAtCatchStmtClass:
2122 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S));
2124 case Stmt::ObjCAutoreleasePoolStmtClass:
2125 return VisitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(S));
2127 case Stmt::ObjCAtSynchronizedStmtClass:
2128 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S));
2130 case Stmt::ObjCAtThrowStmtClass:
2131 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S));
2133 case Stmt::ObjCAtTryStmtClass:
2134 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S));
2136 case Stmt::ObjCForCollectionStmtClass:
2137 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S));
2139 case Stmt::ObjCMessageExprClass:
2140 return VisitObjCMessageExpr(cast<ObjCMessageExpr>(S), asc);
2142 case Stmt::OpaqueValueExprClass:
2145 case Stmt::PseudoObjectExprClass:
2146 return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S));
2148 case Stmt::ReturnStmtClass:
2149 return VisitReturnStmt(cast<ReturnStmt>(S));
2151 case Stmt::SEHExceptStmtClass:
2152 return VisitSEHExceptStmt(cast<SEHExceptStmt>(S));
2154 case Stmt::SEHFinallyStmtClass:
2155 return VisitSEHFinallyStmt(cast<SEHFinallyStmt>(S));
2157 case Stmt::SEHLeaveStmtClass:
2158 return VisitSEHLeaveStmt(cast<SEHLeaveStmt>(S));
2160 case Stmt::SEHTryStmtClass:
2161 return VisitSEHTryStmt(cast<SEHTryStmt>(S));
2163 case Stmt::UnaryExprOrTypeTraitExprClass:
2164 return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S),
2167 case Stmt::StmtExprClass:
2168 return VisitStmtExpr(cast<StmtExpr>(S), asc);
2170 case Stmt::SwitchStmtClass:
2171 return VisitSwitchStmt(cast<SwitchStmt>(S));
2173 case Stmt::UnaryOperatorClass:
2174 return VisitUnaryOperator(cast<UnaryOperator>(S), asc);
2176 case Stmt::WhileStmtClass:
2177 return VisitWhileStmt(cast<WhileStmt>(S));
2181 CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) {
2182 if (asc.alwaysAdd(*this, S)) {
2184 appendStmt(Block, S);
2187 return VisitChildren(S);
2190 /// VisitChildren - Visit the children of a Stmt.
2191 CFGBlock *CFGBuilder::VisitChildren(Stmt *S) {
2192 CFGBlock *B = Block;
2194 // Visit the children in their reverse order so that they appear in
2195 // left-to-right (natural) order in the CFG.
2196 reverse_children RChildren(S);
2197 for (reverse_children::iterator I = RChildren.begin(), E = RChildren.end();
2199 if (Stmt *Child = *I)
2200 if (CFGBlock *R = Visit(Child))
2206 CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A,
2207 AddStmtChoice asc) {
2208 AddressTakenLabels.insert(A->getLabel());
2210 if (asc.alwaysAdd(*this, A)) {
2212 appendStmt(Block, A);
2218 CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U,
2219 AddStmtChoice asc) {
2220 if (asc.alwaysAdd(*this, U)) {
2222 appendStmt(Block, U);
2225 return Visit(U->getSubExpr(), AddStmtChoice());
2228 CFGBlock *CFGBuilder::VisitLogicalOperator(BinaryOperator *B) {
2229 CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2230 appendStmt(ConfluenceBlock, B);
2235 return VisitLogicalOperator(B, nullptr, ConfluenceBlock,
2236 ConfluenceBlock).first;
2239 std::pair<CFGBlock*, CFGBlock*>
2240 CFGBuilder::VisitLogicalOperator(BinaryOperator *B,
2242 CFGBlock *TrueBlock,
2243 CFGBlock *FalseBlock) {
2244 // Introspect the RHS. If it is a nested logical operation, we recursively
2245 // build the CFG using this function. Otherwise, resort to default
2246 // CFG construction behavior.
2247 Expr *RHS = B->getRHS()->IgnoreParens();
2248 CFGBlock *RHSBlock, *ExitBlock;
2251 if (BinaryOperator *B_RHS = dyn_cast<BinaryOperator>(RHS))
2252 if (B_RHS->isLogicalOp()) {
2253 std::tie(RHSBlock, ExitBlock) =
2254 VisitLogicalOperator(B_RHS, Term, TrueBlock, FalseBlock);
2258 // The RHS is not a nested logical operation. Don't push the terminator
2259 // down further, but instead visit RHS and construct the respective
2260 // pieces of the CFG, and link up the RHSBlock with the terminator
2261 // we have been provided.
2262 ExitBlock = RHSBlock = createBlock(false);
2264 // Even though KnownVal is only used in the else branch of the next
2265 // conditional, tryEvaluateBool performs additional checking on the
2266 // Expr, so it should be called unconditionally.
2267 TryResult KnownVal = tryEvaluateBool(RHS);
2268 if (!KnownVal.isKnown())
2269 KnownVal = tryEvaluateBool(B);
2272 assert(TrueBlock == FalseBlock);
2273 addSuccessor(RHSBlock, TrueBlock);
2276 RHSBlock->setTerminator(Term);
2277 addSuccessor(RHSBlock, TrueBlock, !KnownVal.isFalse());
2278 addSuccessor(RHSBlock, FalseBlock, !KnownVal.isTrue());
2282 RHSBlock = addStmt(RHS);
2287 return std::make_pair(nullptr, nullptr);
2289 // Generate the blocks for evaluating the LHS.
2290 Expr *LHS = B->getLHS()->IgnoreParens();
2292 if (BinaryOperator *B_LHS = dyn_cast<BinaryOperator>(LHS))
2293 if (B_LHS->isLogicalOp()) {
2294 if (B->getOpcode() == BO_LOr)
2295 FalseBlock = RHSBlock;
2297 TrueBlock = RHSBlock;
2299 // For the LHS, treat 'B' as the terminator that we want to sink
2300 // into the nested branch. The RHS always gets the top-most
2302 return VisitLogicalOperator(B_LHS, B, TrueBlock, FalseBlock);
2305 // Create the block evaluating the LHS.
2306 // This contains the '&&' or '||' as the terminator.
2307 CFGBlock *LHSBlock = createBlock(false);
2308 LHSBlock->setTerminator(B);
2311 CFGBlock *EntryLHSBlock = addStmt(LHS);
2314 return std::make_pair(nullptr, nullptr);
2316 // See if this is a known constant.
2317 TryResult KnownVal = tryEvaluateBool(LHS);
2319 // Now link the LHSBlock with RHSBlock.
2320 if (B->getOpcode() == BO_LOr) {
2321 addSuccessor(LHSBlock, TrueBlock, !KnownVal.isFalse());
2322 addSuccessor(LHSBlock, RHSBlock, !KnownVal.isTrue());
2324 assert(B->getOpcode() == BO_LAnd);
2325 addSuccessor(LHSBlock, RHSBlock, !KnownVal.isFalse());
2326 addSuccessor(LHSBlock, FalseBlock, !KnownVal.isTrue());
2329 return std::make_pair(EntryLHSBlock, ExitBlock);
2332 CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B,
2333 AddStmtChoice asc) {
2335 if (B->isLogicalOp())
2336 return VisitLogicalOperator(B);
2338 if (B->getOpcode() == BO_Comma) { // ,
2340 appendStmt(Block, B);
2341 addStmt(B->getRHS());
2342 return addStmt(B->getLHS());
2345 if (B->isAssignmentOp()) {
2346 if (asc.alwaysAdd(*this, B)) {
2348 appendStmt(Block, B);
2351 return Visit(B->getRHS());
2354 if (asc.alwaysAdd(*this, B)) {
2356 appendStmt(Block, B);
2359 CFGBlock *RBlock = Visit(B->getRHS());
2360 CFGBlock *LBlock = Visit(B->getLHS());
2361 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr
2362 // containing a DoStmt, and the LHS doesn't create a new block, then we should
2363 // return RBlock. Otherwise we'll incorrectly return NULL.
2364 return (LBlock ? LBlock : RBlock);
2367 CFGBlock *CFGBuilder::VisitNoRecurse(Expr *E, AddStmtChoice asc) {
2368 if (asc.alwaysAdd(*this, E)) {
2370 appendStmt(Block, E);
2375 CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) {
2376 // "break" is a control-flow statement. Thus we stop processing the current
2381 // Now create a new block that ends with the break statement.
2382 Block = createBlock(false);
2383 Block->setTerminator(B);
2385 // If there is no target for the break, then we are looking at an incomplete
2386 // AST. This means that the CFG cannot be constructed.
2387 if (BreakJumpTarget.block) {
2388 addAutomaticObjHandling(ScopePos, BreakJumpTarget.scopePosition, B);
2389 addSuccessor(Block, BreakJumpTarget.block);
2396 static bool CanThrow(Expr *E, ASTContext &Ctx) {
2397 QualType Ty = E->getType();
2398 if (Ty->isFunctionPointerType())
2399 Ty = Ty->getAs<PointerType>()->getPointeeType();
2400 else if (Ty->isBlockPointerType())
2401 Ty = Ty->getAs<BlockPointerType>()->getPointeeType();
2403 const FunctionType *FT = Ty->getAs<FunctionType>();
2405 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT))
2406 if (!isUnresolvedExceptionSpec(Proto->getExceptionSpecType()) &&
2413 CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) {
2414 // Compute the callee type.
2415 QualType calleeType = C->getCallee()->getType();
2416 if (calleeType == Context->BoundMemberTy) {
2417 QualType boundType = Expr::findBoundMemberType(C->getCallee());
2419 // We should only get a null bound type if processing a dependent
2420 // CFG. Recover by assuming nothing.
2421 if (!boundType.isNull()) calleeType = boundType;
2424 findConstructionContextsForArguments(C);
2426 // If this is a call to a no-return function, this stops the block here.
2427 bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn();
2429 bool AddEHEdge = false;
2431 // Languages without exceptions are assumed to not throw.
2432 if (Context->getLangOpts().Exceptions) {
2433 if (BuildOpts.AddEHEdges)
2437 // If this is a call to a builtin function, it might not actually evaluate
2438 // its arguments. Don't add them to the CFG if this is the case.
2439 bool OmitArguments = false;
2441 if (FunctionDecl *FD = C->getDirectCallee()) {
2442 if (FD->isNoReturn() || C->isBuiltinAssumeFalse(*Context))
2444 if (FD->hasAttr<NoThrowAttr>())
2446 if (FD->getBuiltinID() == Builtin::BI__builtin_object_size)
2447 OmitArguments = true;
2450 if (!CanThrow(C->getCallee(), *Context))
2453 if (OmitArguments) {
2454 assert(!NoReturn && "noreturn calls with unevaluated args not implemented");
2455 assert(!AddEHEdge && "EH calls with unevaluated args not implemented");
2457 appendStmt(Block, C);
2458 return Visit(C->getCallee());
2461 if (!NoReturn && !AddEHEdge) {
2463 appendCall(Block, C);
2465 return VisitChildren(C);
2475 Block = createNoReturnBlock();
2477 Block = createBlock();
2479 appendCall(Block, C);
2482 // Add exceptional edges.
2483 if (TryTerminatedBlock)
2484 addSuccessor(Block, TryTerminatedBlock);
2486 addSuccessor(Block, &cfg->getExit());
2489 return VisitChildren(C);
2492 CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C,
2493 AddStmtChoice asc) {
2494 CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2495 appendStmt(ConfluenceBlock, C);
2499 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2500 Succ = ConfluenceBlock;
2502 CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd);
2506 Succ = ConfluenceBlock;
2508 CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd);
2512 Block = createBlock(false);
2513 // See if this is a known constant.
2514 const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2515 addSuccessor(Block, KnownVal.isFalse() ? nullptr : LHSBlock);
2516 addSuccessor(Block, KnownVal.isTrue() ? nullptr : RHSBlock);
2517 Block->setTerminator(C);
2518 return addStmt(C->getCond());
2521 CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) {
2522 LocalScope::const_iterator scopeBeginPos = ScopePos;
2523 addLocalScopeForStmt(C);
2525 if (!C->body_empty() && !isa<ReturnStmt>(*C->body_rbegin())) {
2526 // If the body ends with a ReturnStmt, the dtors will be added in
2528 addAutomaticObjHandling(ScopePos, scopeBeginPos, C);
2531 CFGBlock *LastBlock = Block;
2533 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend();
2535 // If we hit a segment of code just containing ';' (NullStmts), we can
2536 // get a null block back. In such cases, just use the LastBlock
2537 if (CFGBlock *newBlock = addStmt(*I))
2538 LastBlock = newBlock;
2547 CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C,
2548 AddStmtChoice asc) {
2549 const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C);
2550 const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : nullptr);
2552 // Create the confluence block that will "merge" the results of the ternary
2554 CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
2555 appendStmt(ConfluenceBlock, C);
2559 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
2561 // Create a block for the LHS expression if there is an LHS expression. A
2562 // GCC extension allows LHS to be NULL, causing the condition to be the
2563 // value that is returned instead.
2564 // e.g: x ?: y is shorthand for: x ? x : y;
2565 Succ = ConfluenceBlock;
2567 CFGBlock *LHSBlock = nullptr;
2568 const Expr *trueExpr = C->getTrueExpr();
2569 if (trueExpr != opaqueValue) {
2570 LHSBlock = Visit(C->getTrueExpr(), alwaysAdd);
2576 LHSBlock = ConfluenceBlock;
2578 // Create the block for the RHS expression.
2579 Succ = ConfluenceBlock;
2580 CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd);
2584 // If the condition is a logical '&&' or '||', build a more accurate CFG.
2585 if (BinaryOperator *Cond =
2586 dyn_cast<BinaryOperator>(C->getCond()->IgnoreParens()))
2587 if (Cond->isLogicalOp())
2588 return VisitLogicalOperator(Cond, C, LHSBlock, RHSBlock).first;
2590 // Create the block that will contain the condition.
2591 Block = createBlock(false);
2593 // See if this is a known constant.
2594 const TryResult& KnownVal = tryEvaluateBool(C->getCond());
2595 addSuccessor(Block, LHSBlock, !KnownVal.isFalse());
2596 addSuccessor(Block, RHSBlock, !KnownVal.isTrue());
2597 Block->setTerminator(C);
2598 Expr *condExpr = C->getCond();
2601 // Run the condition expression if it's not trivially expressed in
2602 // terms of the opaque value (or if there is no opaque value).
2603 if (condExpr != opaqueValue)
2606 // Before that, run the common subexpression if there was one.
2607 // At least one of this or the above will be run.
2608 return addStmt(BCO->getCommon());
2611 return addStmt(condExpr);
2614 CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) {
2615 // Check if the Decl is for an __label__. If so, elide it from the
2617 if (isa<LabelDecl>(*DS->decl_begin()))
2620 // This case also handles static_asserts.
2621 if (DS->isSingleDecl())
2622 return VisitDeclSubExpr(DS);
2624 CFGBlock *B = nullptr;
2626 // Build an individual DeclStmt for each decl.
2627 for (DeclStmt::reverse_decl_iterator I = DS->decl_rbegin(),
2628 E = DS->decl_rend();
2630 // Get the alignment of the new DeclStmt, padding out to >=8 bytes.
2631 unsigned A = alignof(DeclStmt) < 8 ? 8 : alignof(DeclStmt);
2633 // Allocate the DeclStmt using the BumpPtrAllocator. It will get
2634 // automatically freed with the CFG.
2635 DeclGroupRef DG(*I);
2637 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A);
2638 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D));
2639 cfg->addSyntheticDeclStmt(DSNew, DS);
2641 // Append the fake DeclStmt to block.
2642 B = VisitDeclSubExpr(DSNew);
2648 /// VisitDeclSubExpr - Utility method to add block-level expressions for
2649 /// DeclStmts and initializers in them.
2650 CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) {
2651 assert(DS->isSingleDecl() && "Can handle single declarations only.");
2652 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl());
2655 // Of everything that can be declared in a DeclStmt, only VarDecls impact
2656 // runtime semantics.
2660 bool HasTemporaries = false;
2662 // Guard static initializers under a branch.
2663 CFGBlock *blockAfterStaticInit = nullptr;
2665 if (BuildOpts.AddStaticInitBranches && VD->isStaticLocal()) {
2666 // For static variables, we need to create a branch to track
2667 // whether or not they are initialized.
2674 blockAfterStaticInit = Succ;
2677 // Destructors of temporaries in initialization expression should be called
2678 // after initialization finishes.
2679 Expr *Init = VD->getInit();
2681 HasTemporaries = isa<ExprWithCleanups>(Init);
2683 if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
2684 // Generate destructors for temporaries in initialization expression.
2685 TempDtorContext Context;
2686 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
2687 /*BindToTemporary=*/false, Context);
2692 appendStmt(Block, DS);
2694 findConstructionContexts(
2695 ConstructionContextLayer::create(cfg->getBumpVectorContext(), DS),
2698 // Keep track of the last non-null block, as 'Block' can be nulled out
2699 // if the initializer expression is something like a 'while' in a
2700 // statement-expression.
2701 CFGBlock *LastBlock = Block;
2704 if (HasTemporaries) {
2705 // For expression with temporaries go directly to subexpression to omit
2706 // generating destructors for the second time.
2707 ExprWithCleanups *EC = cast<ExprWithCleanups>(Init);
2708 if (CFGBlock *newBlock = Visit(EC->getSubExpr()))
2709 LastBlock = newBlock;
2712 if (CFGBlock *newBlock = Visit(Init))
2713 LastBlock = newBlock;
2717 // If the type of VD is a VLA, then we must process its size expressions.
2718 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr());
2719 VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr())) {
2720 if (CFGBlock *newBlock = addStmt(VA->getSizeExpr()))
2721 LastBlock = newBlock;
2724 maybeAddScopeBeginForVarDecl(Block, VD, DS);
2726 // Remove variable from local scope.
2727 if (ScopePos && VD == *ScopePos)
2730 CFGBlock *B = LastBlock;
2731 if (blockAfterStaticInit) {
2733 Block = createBlock(false);
2734 Block->setTerminator(DS);
2735 addSuccessor(Block, blockAfterStaticInit);
2736 addSuccessor(Block, B);
2743 CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) {
2744 // We may see an if statement in the middle of a basic block, or it may be the
2745 // first statement we are processing. In either case, we create a new basic
2746 // block. First, we create the blocks for the then...else statements, and
2747 // then we create the block containing the if statement. If we were in the
2748 // middle of a block, we stop processing that block. That block is then the
2749 // implicit successor for the "then" and "else" clauses.
2751 // Save local scope position because in case of condition variable ScopePos
2752 // won't be restored when traversing AST.
2753 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2755 // Create local scope for C++17 if init-stmt if one exists.
2756 if (Stmt *Init = I->getInit())
2757 addLocalScopeForStmt(Init);
2759 // Create local scope for possible condition variable.
2760 // Store scope position. Add implicit destructor.
2761 if (VarDecl *VD = I->getConditionVariable())
2762 addLocalScopeForVarDecl(VD);
2764 addAutomaticObjHandling(ScopePos, save_scope_pos.get(), I);
2766 // The block we were processing is now finished. Make it the successor
2774 // Process the false branch.
2775 CFGBlock *ElseBlock = Succ;
2777 if (Stmt *Else = I->getElse()) {
2778 SaveAndRestore<CFGBlock*> sv(Succ);
2780 // NULL out Block so that the recursive call to Visit will
2781 // create a new basic block.
2784 // If branch is not a compound statement create implicit scope
2785 // and add destructors.
2786 if (!isa<CompoundStmt>(Else))
2787 addLocalScopeAndDtors(Else);
2789 ElseBlock = addStmt(Else);
2791 if (!ElseBlock) // Can occur when the Else body has all NullStmts.
2792 ElseBlock = sv.get();
2799 // Process the true branch.
2800 CFGBlock *ThenBlock;
2802 Stmt *Then = I->getThen();
2804 SaveAndRestore<CFGBlock*> sv(Succ);
2807 // If branch is not a compound statement create implicit scope
2808 // and add destructors.
2809 if (!isa<CompoundStmt>(Then))
2810 addLocalScopeAndDtors(Then);
2812 ThenBlock = addStmt(Then);
2815 // We can reach here if the "then" body has all NullStmts.
2816 // Create an empty block so we can distinguish between true and false
2817 // branches in path-sensitive analyses.
2818 ThenBlock = createBlock(false);
2819 addSuccessor(ThenBlock, sv.get());
2826 // Specially handle "if (expr1 || ...)" and "if (expr1 && ...)" by
2827 // having these handle the actual control-flow jump. Note that
2828 // if we introduce a condition variable, e.g. "if (int x = exp1 || exp2)"
2829 // we resort to the old control-flow behavior. This special handling
2830 // removes infeasible paths from the control-flow graph by having the
2831 // control-flow transfer of '&&' or '||' go directly into the then/else
2833 BinaryOperator *Cond =
2834 I->getConditionVariable()
2836 : dyn_cast<BinaryOperator>(I->getCond()->IgnoreParens());
2837 CFGBlock *LastBlock;
2838 if (Cond && Cond->isLogicalOp())
2839 LastBlock = VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first;
2841 // Now create a new block containing the if statement.
2842 Block = createBlock(false);
2844 // Set the terminator of the new block to the If statement.
2845 Block->setTerminator(I);
2847 // See if this is a known constant.
2848 const TryResult &KnownVal = tryEvaluateBool(I->getCond());
2850 // Add the successors. If we know that specific branches are
2851 // unreachable, inform addSuccessor() of that knowledge.
2852 addSuccessor(Block, ThenBlock, /* isReachable = */ !KnownVal.isFalse());
2853 addSuccessor(Block, ElseBlock, /* isReachable = */ !KnownVal.isTrue());
2855 // Add the condition as the last statement in the new block. This may
2856 // create new blocks as the condition may contain control-flow. Any newly
2857 // created blocks will be pointed to be "Block".
2858 LastBlock = addStmt(I->getCond());
2860 // If the IfStmt contains a condition variable, add it and its
2861 // initializer to the CFG.
2862 if (const DeclStmt* DS = I->getConditionVariableDeclStmt()) {
2864 LastBlock = addStmt(const_cast<DeclStmt *>(DS));
2868 // Finally, if the IfStmt contains a C++17 init-stmt, add it to the CFG.
2869 if (Stmt *Init = I->getInit()) {
2871 LastBlock = addStmt(Init);
2877 CFGBlock *CFGBuilder::VisitReturnStmt(ReturnStmt *R) {
2878 // If we were in the middle of a block we stop processing that block.
2880 // NOTE: If a "return" appears in the middle of a block, this means that the
2881 // code afterwards is DEAD (unreachable). We still keep a basic block
2882 // for that code; a simple "mark-and-sweep" from the entry block will be
2883 // able to report such dead blocks.
2885 // Create the new block.
2886 Block = createBlock(false);
2888 addAutomaticObjHandling(ScopePos, LocalScope::const_iterator(), R);
2890 findConstructionContexts(
2891 ConstructionContextLayer::create(cfg->getBumpVectorContext(), R),
2894 // If the one of the destructors does not return, we already have the Exit
2895 // block as a successor.
2896 if (!Block->hasNoReturnElement())
2897 addSuccessor(Block, &cfg->getExit());
2899 // Add the return statement to the block. This may create new blocks if R
2900 // contains control-flow (short-circuit operations).
2901 return VisitStmt(R, AddStmtChoice::AlwaysAdd);
2904 CFGBlock *CFGBuilder::VisitSEHExceptStmt(SEHExceptStmt *ES) {
2905 // SEHExceptStmt are treated like labels, so they are the first statement in a
2908 // Save local scope position because in case of exception variable ScopePos
2909 // won't be restored when traversing AST.
2910 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2912 addStmt(ES->getBlock());
2913 CFGBlock *SEHExceptBlock = Block;
2914 if (!SEHExceptBlock)
2915 SEHExceptBlock = createBlock();
2917 appendStmt(SEHExceptBlock, ES);
2919 // Also add the SEHExceptBlock as a label, like with regular labels.
2920 SEHExceptBlock->setLabel(ES);
2922 // Bail out if the CFG is bad.
2926 // We set Block to NULL to allow lazy creation of a new block (if necessary).
2929 return SEHExceptBlock;
2932 CFGBlock *CFGBuilder::VisitSEHFinallyStmt(SEHFinallyStmt *FS) {
2933 return VisitCompoundStmt(FS->getBlock());
2936 CFGBlock *CFGBuilder::VisitSEHLeaveStmt(SEHLeaveStmt *LS) {
2937 // "__leave" is a control-flow statement. Thus we stop processing the current
2942 // Now create a new block that ends with the __leave statement.
2943 Block = createBlock(false);
2944 Block->setTerminator(LS);
2946 // If there is no target for the __leave, then we are looking at an incomplete
2947 // AST. This means that the CFG cannot be constructed.
2948 if (SEHLeaveJumpTarget.block) {
2949 addAutomaticObjHandling(ScopePos, SEHLeaveJumpTarget.scopePosition, LS);
2950 addSuccessor(Block, SEHLeaveJumpTarget.block);
2957 CFGBlock *CFGBuilder::VisitSEHTryStmt(SEHTryStmt *Terminator) {
2958 // "__try"/"__except"/"__finally" is a control-flow statement. Thus we stop
2959 // processing the current block.
2960 CFGBlock *SEHTrySuccessor = nullptr;
2965 SEHTrySuccessor = Block;
2966 } else SEHTrySuccessor = Succ;
2968 // FIXME: Implement __finally support.
2969 if (Terminator->getFinallyHandler())
2972 CFGBlock *PrevSEHTryTerminatedBlock = TryTerminatedBlock;
2974 // Create a new block that will contain the __try statement.
2975 CFGBlock *NewTryTerminatedBlock = createBlock(false);
2977 // Add the terminator in the __try block.
2978 NewTryTerminatedBlock->setTerminator(Terminator);
2980 if (SEHExceptStmt *Except = Terminator->getExceptHandler()) {
2981 // The code after the try is the implicit successor if there's an __except.
2982 Succ = SEHTrySuccessor;
2984 CFGBlock *ExceptBlock = VisitSEHExceptStmt(Except);
2987 // Add this block to the list of successors for the block with the try
2989 addSuccessor(NewTryTerminatedBlock, ExceptBlock);
2991 if (PrevSEHTryTerminatedBlock)
2992 addSuccessor(NewTryTerminatedBlock, PrevSEHTryTerminatedBlock);
2994 addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
2996 // The code after the try is the implicit successor.
2997 Succ = SEHTrySuccessor;
2999 // Save the current "__try" context.
3000 SaveAndRestore<CFGBlock *> save_try(TryTerminatedBlock,
3001 NewTryTerminatedBlock);
3002 cfg->addTryDispatchBlock(TryTerminatedBlock);
3004 // Save the current value for the __leave target.
3005 // All __leaves should go to the code following the __try
3006 // (FIXME: or if the __try has a __finally, to the __finally.)
3007 SaveAndRestore<JumpTarget> save_break(SEHLeaveJumpTarget);
3008 SEHLeaveJumpTarget = JumpTarget(SEHTrySuccessor, ScopePos);
3010 assert(Terminator->getTryBlock() && "__try must contain a non-NULL body");
3012 return addStmt(Terminator->getTryBlock());
3015 CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) {
3016 // Get the block of the labeled statement. Add it to our map.
3017 addStmt(L->getSubStmt());
3018 CFGBlock *LabelBlock = Block;
3020 if (!LabelBlock) // This can happen when the body is empty, i.e.
3021 LabelBlock = createBlock(); // scopes that only contains NullStmts.
3023 assert(LabelMap.find(L->getDecl()) == LabelMap.end() &&
3024 "label already in map");
3025 LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos);
3027 // Labels partition blocks, so this is the end of the basic block we were
3028 // processing (L is the block's label). Because this is label (and we have
3029 // already processed the substatement) there is no extra control-flow to worry
3031 LabelBlock->setLabel(L);
3035 // We set Block to NULL to allow lazy creation of a new block (if necessary);
3038 // This block is now the implicit successor of other blocks.
3044 CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) {
3045 CFGBlock *LastBlock = VisitNoRecurse(E, asc);
3046 for (const BlockDecl::Capture &CI : E->getBlockDecl()->captures()) {
3047 if (Expr *CopyExpr = CI.getCopyExpr()) {
3048 CFGBlock *Tmp = Visit(CopyExpr);
3056 CFGBlock *CFGBuilder::VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc) {
3057 CFGBlock *LastBlock = VisitNoRecurse(E, asc);
3058 for (LambdaExpr::capture_init_iterator it = E->capture_init_begin(),
3059 et = E->capture_init_end(); it != et; ++it) {
3060 if (Expr *Init = *it) {
3061 CFGBlock *Tmp = Visit(Init);
3069 CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) {
3070 // Goto is a control-flow statement. Thus we stop processing the current
3071 // block and create a new one.
3073 Block = createBlock(false);
3074 Block->setTerminator(G);
3076 // If we already know the mapping to the label block add the successor now.
3077 LabelMapTy::iterator I = LabelMap.find(G->getLabel());
3079 if (I == LabelMap.end())
3080 // We will need to backpatch this block later.
3081 BackpatchBlocks.push_back(JumpSource(Block, ScopePos));
3083 JumpTarget JT = I->second;
3084 addAutomaticObjHandling(ScopePos, JT.scopePosition, G);
3085 addSuccessor(Block, JT.block);
3091 CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) {
3092 CFGBlock *LoopSuccessor = nullptr;
3094 // Save local scope position because in case of condition variable ScopePos
3095 // won't be restored when traversing AST.
3096 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3098 // Create local scope for init statement and possible condition variable.
3099 // Add destructor for init statement and condition variable.
3100 // Store scope position for continue statement.
3101 if (Stmt *Init = F->getInit())
3102 addLocalScopeForStmt(Init);
3103 LocalScope::const_iterator LoopBeginScopePos = ScopePos;
3105 if (VarDecl *VD = F->getConditionVariable())
3106 addLocalScopeForVarDecl(VD);
3107 LocalScope::const_iterator ContinueScopePos = ScopePos;
3109 addAutomaticObjHandling(ScopePos, save_scope_pos.get(), F);
3113 // "for" is a control-flow statement. Thus we stop processing the current
3118 LoopSuccessor = Block;
3120 LoopSuccessor = Succ;
3122 // Save the current value for the break targets.
3123 // All breaks should go to the code following the loop.
3124 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3125 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3127 CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
3129 // Now create the loop body.
3131 assert(F->getBody());
3133 // Save the current values for Block, Succ, continue and break targets.
3134 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3135 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
3137 // Create an empty block to represent the transition block for looping back
3138 // to the head of the loop. If we have increment code, it will
3139 // go in this block as well.
3140 Block = Succ = TransitionBlock = createBlock(false);
3141 TransitionBlock->setLoopTarget(F);
3143 if (Stmt *I = F->getInc()) {
3144 // Generate increment code in its own basic block. This is the target of
3145 // continue statements.
3149 // Finish up the increment (or empty) block if it hasn't been already.
3151 assert(Block == Succ);
3157 // The starting block for the loop increment is the block that should
3158 // represent the 'loop target' for looping back to the start of the loop.
3159 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
3160 ContinueJumpTarget.block->setLoopTarget(F);
3162 // Loop body should end with destructor of Condition variable (if any).
3163 addAutomaticObjHandling(ScopePos, LoopBeginScopePos, F);
3165 // If body is not a compound statement create implicit scope
3166 // and add destructors.
3167 if (!isa<CompoundStmt>(F->getBody()))
3168 addLocalScopeAndDtors(F->getBody());
3170 // Now populate the body block, and in the process create new blocks as we
3171 // walk the body of the loop.
3172 BodyBlock = addStmt(F->getBody());
3175 // In the case of "for (...;...;...);" we can have a null BodyBlock.
3176 // Use the continue jump target as the proxy for the body.
3177 BodyBlock = ContinueJumpTarget.block;
3183 // Because of short-circuit evaluation, the condition of the loop can span
3184 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3185 // evaluate the condition.
3186 CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
3189 Expr *C = F->getCond();
3190 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3192 // Specially handle logical operators, which have a slightly
3193 // more optimal CFG representation.
3194 if (BinaryOperator *Cond =
3195 dyn_cast_or_null<BinaryOperator>(C ? C->IgnoreParens() : nullptr))
3196 if (Cond->isLogicalOp()) {
3197 std::tie(EntryConditionBlock, ExitConditionBlock) =
3198 VisitLogicalOperator(Cond, F, BodyBlock, LoopSuccessor);
3202 // The default case when not handling logical operators.
3203 EntryConditionBlock = ExitConditionBlock = createBlock(false);
3204 ExitConditionBlock->setTerminator(F);
3206 // See if this is a known constant.
3207 TryResult KnownVal(true);
3210 // Now add the actual condition to the condition block.
3211 // Because the condition itself may contain control-flow, new blocks may
3212 // be created. Thus we update "Succ" after adding the condition.
3213 Block = ExitConditionBlock;
3214 EntryConditionBlock = addStmt(C);
3216 // If this block contains a condition variable, add both the condition
3217 // variable and initializer to the CFG.
3218 if (VarDecl *VD = F->getConditionVariable()) {
3219 if (Expr *Init = VD->getInit()) {
3221 const DeclStmt *DS = F->getConditionVariableDeclStmt();
3222 assert(DS->isSingleDecl());
3223 findConstructionContexts(
3224 ConstructionContextLayer::create(cfg->getBumpVectorContext(), DS),
3226 appendStmt(Block, DS);
3227 EntryConditionBlock = addStmt(Init);
3228 assert(Block == EntryConditionBlock);
3229 maybeAddScopeBeginForVarDecl(EntryConditionBlock, VD, C);
3233 if (Block && badCFG)
3236 KnownVal = tryEvaluateBool(C);
3239 // Add the loop body entry as a successor to the condition.
3240 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
3241 // Link up the condition block with the code that follows the loop. (the
3243 addSuccessor(ExitConditionBlock,
3244 KnownVal.isTrue() ? nullptr : LoopSuccessor);
3247 // Link up the loop-back block to the entry condition block.
3248 addSuccessor(TransitionBlock, EntryConditionBlock);
3250 // The condition block is the implicit successor for any code above the loop.
3251 Succ = EntryConditionBlock;
3253 // If the loop contains initialization, create a new block for those
3254 // statements. This block can also contain statements that precede the loop.
3255 if (Stmt *I = F->getInit()) {
3256 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3257 ScopePos = LoopBeginScopePos;
3258 Block = createBlock();
3262 // There is no loop initialization. We are thus basically a while loop.
3263 // NULL out Block to force lazy block construction.
3265 Succ = EntryConditionBlock;
3266 return EntryConditionBlock;
3270 CFGBuilder::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *MTE,
3271 AddStmtChoice asc) {
3272 findConstructionContexts(
3273 ConstructionContextLayer::create(cfg->getBumpVectorContext(), MTE),
3274 MTE->getTemporary());
3276 return VisitStmt(MTE, asc);
3279 CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) {
3280 if (asc.alwaysAdd(*this, M)) {
3282 appendStmt(Block, M);
3284 return Visit(M->getBase());
3287 CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) {
3288 // Objective-C fast enumeration 'for' statements:
3289 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC
3291 // for ( Type newVariable in collection_expression ) { statements }
3296 // 1. collection_expression
3297 // T. jump to loop_entry
3299 // 1. side-effects of element expression
3300 // 1. ObjCForCollectionStmt [performs binding to newVariable]
3301 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil]
3304 // T. jump to loop_entry
3310 // Type existingItem;
3311 // for ( existingItem in expression ) { statements }
3315 // the same with newVariable replaced with existingItem; the binding works
3316 // the same except that for one ObjCForCollectionStmt::getElement() returns
3317 // a DeclStmt and the other returns a DeclRefExpr.
3319 CFGBlock *LoopSuccessor = nullptr;
3324 LoopSuccessor = Block;
3327 LoopSuccessor = Succ;
3329 // Build the condition blocks.
3330 CFGBlock *ExitConditionBlock = createBlock(false);
3332 // Set the terminator for the "exit" condition block.
3333 ExitConditionBlock->setTerminator(S);
3335 // The last statement in the block should be the ObjCForCollectionStmt, which
3336 // performs the actual binding to 'element' and determines if there are any
3337 // more items in the collection.
3338 appendStmt(ExitConditionBlock, S);
3339 Block = ExitConditionBlock;
3341 // Walk the 'element' expression to see if there are any side-effects. We
3342 // generate new blocks as necessary. We DON'T add the statement by default to
3343 // the CFG unless it contains control-flow.
3344 CFGBlock *EntryConditionBlock = Visit(S->getElement(),
3345 AddStmtChoice::NotAlwaysAdd);
3352 // The condition block is the implicit successor for the loop body as well as
3353 // any code above the loop.
3354 Succ = EntryConditionBlock;
3356 // Now create the true branch.
3358 // Save the current values for Succ, continue and break targets.
3359 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3360 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3361 save_break(BreakJumpTarget);
3363 // Add an intermediate block between the BodyBlock and the
3364 // EntryConditionBlock to represent the "loop back" transition, for looping
3365 // back to the head of the loop.
3366 CFGBlock *LoopBackBlock = nullptr;
3367 Succ = LoopBackBlock = createBlock();
3368 LoopBackBlock->setLoopTarget(S);
3370 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3371 ContinueJumpTarget = JumpTarget(Succ, ScopePos);
3373 CFGBlock *BodyBlock = addStmt(S->getBody());
3376 BodyBlock = ContinueJumpTarget.block; // can happen for "for (X in Y) ;"
3382 // This new body block is a successor to our "exit" condition block.
3383 addSuccessor(ExitConditionBlock, BodyBlock);
3386 // Link up the condition block with the code that follows the loop.
3387 // (the false branch).
3388 addSuccessor(ExitConditionBlock, LoopSuccessor);
3390 // Now create a prologue block to contain the collection expression.
3391 Block = createBlock();
3392 return addStmt(S->getCollection());
3395 CFGBlock *CFGBuilder::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) {
3397 return addStmt(S->getSubStmt());
3398 // TODO: consider adding cleanups for the end of @autoreleasepool scope.
3401 CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) {
3402 // FIXME: Add locking 'primitives' to CFG for @synchronized.
3405 CFGBlock *SyncBlock = addStmt(S->getSynchBody());
3407 // The sync body starts its own basic block. This makes it a little easier
3408 // for diagnostic clients.
3417 // Add the @synchronized to the CFG.
3419 appendStmt(Block, S);
3421 // Inline the sync expression.
3422 return addStmt(S->getSynchExpr());
3425 CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) {
3430 CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) {
3433 // Add the PseudoObject as the last thing.
3434 appendStmt(Block, E);
3436 CFGBlock *lastBlock = Block;
3438 // Before that, evaluate all of the semantics in order. In
3439 // CFG-land, that means appending them in reverse order.
3440 for (unsigned i = E->getNumSemanticExprs(); i != 0; ) {
3441 Expr *Semantic = E->getSemanticExpr(--i);
3443 // If the semantic is an opaque value, we're being asked to bind
3444 // it to its source expression.
3445 if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
3446 Semantic = OVE->getSourceExpr();
3448 if (CFGBlock *B = Visit(Semantic))
3455 CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) {
3456 CFGBlock *LoopSuccessor = nullptr;
3458 // Save local scope position because in case of condition variable ScopePos
3459 // won't be restored when traversing AST.
3460 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3462 // Create local scope for possible condition variable.
3463 // Store scope position for continue statement.
3464 LocalScope::const_iterator LoopBeginScopePos = ScopePos;
3465 if (VarDecl *VD = W->getConditionVariable()) {
3466 addLocalScopeForVarDecl(VD);
3467 addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3471 // "while" is a control-flow statement. Thus we stop processing the current
3476 LoopSuccessor = Block;
3479 LoopSuccessor = Succ;
3482 CFGBlock *BodyBlock = nullptr, *TransitionBlock = nullptr;
3484 // Process the loop body.
3486 assert(W->getBody());
3488 // Save the current values for Block, Succ, continue and break targets.
3489 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3490 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3491 save_break(BreakJumpTarget);
3493 // Create an empty block to represent the transition block for looping back
3494 // to the head of the loop.
3495 Succ = TransitionBlock = createBlock(false);
3496 TransitionBlock->setLoopTarget(W);
3497 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos);
3499 // All breaks should go to the code following the loop.
3500 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3502 // Loop body should end with destructor of Condition variable (if any).
3503 addAutomaticObjHandling(ScopePos, LoopBeginScopePos, W);
3505 // If body is not a compound statement create implicit scope
3506 // and add destructors.
3507 if (!isa<CompoundStmt>(W->getBody()))
3508 addLocalScopeAndDtors(W->getBody());
3510 // Create the body. The returned block is the entry to the loop body.
3511 BodyBlock = addStmt(W->getBody());
3514 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;"
3515 else if (Block && badCFG)
3519 // Because of short-circuit evaluation, the condition of the loop can span
3520 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3521 // evaluate the condition.
3522 CFGBlock *EntryConditionBlock = nullptr, *ExitConditionBlock = nullptr;
3525 Expr *C = W->getCond();
3527 // Specially handle logical operators, which have a slightly
3528 // more optimal CFG representation.
3529 if (BinaryOperator *Cond = dyn_cast<BinaryOperator>(C->IgnoreParens()))
3530 if (Cond->isLogicalOp()) {
3531 std::tie(EntryConditionBlock, ExitConditionBlock) =
3532 VisitLogicalOperator(Cond, W, BodyBlock, LoopSuccessor);
3536 // The default case when not handling logical operators.
3537 ExitConditionBlock = createBlock(false);
3538 ExitConditionBlock->setTerminator(W);
3540 // Now add the actual condition to the condition block.
3541 // Because the condition itself may contain control-flow, new blocks may
3542 // be created. Thus we update "Succ" after adding the condition.
3543 Block = ExitConditionBlock;
3544 Block = EntryConditionBlock = addStmt(C);
3546 // If this block contains a condition variable, add both the condition
3547 // variable and initializer to the CFG.
3548 if (VarDecl *VD = W->getConditionVariable()) {
3549 if (Expr *Init = VD->getInit()) {
3551 const DeclStmt *DS = W->getConditionVariableDeclStmt();
3552 assert(DS->isSingleDecl());
3553 findConstructionContexts(
3554 ConstructionContextLayer::create(cfg->getBumpVectorContext(),
3555 const_cast<DeclStmt *>(DS)),
3557 appendStmt(Block, DS);
3558 EntryConditionBlock = addStmt(Init);
3559 assert(Block == EntryConditionBlock);
3560 maybeAddScopeBeginForVarDecl(EntryConditionBlock, VD, C);
3564 if (Block && badCFG)
3567 // See if this is a known constant.
3568 const TryResult& KnownVal = tryEvaluateBool(C);
3570 // Add the loop body entry as a successor to the condition.
3571 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? nullptr : BodyBlock);
3572 // Link up the condition block with the code that follows the loop. (the
3574 addSuccessor(ExitConditionBlock,
3575 KnownVal.isTrue() ? nullptr : LoopSuccessor);
3578 // Link up the loop-back block to the entry condition block.
3579 addSuccessor(TransitionBlock, EntryConditionBlock);
3581 // There can be no more statements in the condition block since we loop back
3582 // to this block. NULL out Block to force lazy creation of another block.
3585 // Return the condition block, which is the dominating block for the loop.
3586 Succ = EntryConditionBlock;
3587 return EntryConditionBlock;
3590 CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) {
3591 // FIXME: For now we pretend that @catch and the code it contains does not
3596 CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) {
3597 // FIXME: This isn't complete. We basically treat @throw like a return
3600 // If we were in the middle of a block we stop processing that block.
3604 // Create the new block.
3605 Block = createBlock(false);
3607 // The Exit block is the only successor.
3608 addSuccessor(Block, &cfg->getExit());
3610 // Add the statement to the block. This may create new blocks if S contains
3611 // control-flow (short-circuit operations).
3612 return VisitStmt(S, AddStmtChoice::AlwaysAdd);
3615 CFGBlock *CFGBuilder::VisitObjCMessageExpr(ObjCMessageExpr *ME,
3616 AddStmtChoice asc) {
3617 findConstructionContextsForArguments(ME);
3620 appendObjCMessage(Block, ME);
3622 return VisitChildren(ME);
3625 CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) {
3626 // If we were in the middle of a block we stop processing that block.
3630 // Create the new block.
3631 Block = createBlock(false);
3633 if (TryTerminatedBlock)
3634 // The current try statement is the only successor.
3635 addSuccessor(Block, TryTerminatedBlock);
3637 // otherwise the Exit block is the only successor.
3638 addSuccessor(Block, &cfg->getExit());
3640 // Add the statement to the block. This may create new blocks if S contains
3641 // control-flow (short-circuit operations).
3642 return VisitStmt(T, AddStmtChoice::AlwaysAdd);
3645 CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) {
3646 CFGBlock *LoopSuccessor = nullptr;
3650 // "do...while" is a control-flow statement. Thus we stop processing the
3655 LoopSuccessor = Block;
3657 LoopSuccessor = Succ;
3659 // Because of short-circuit evaluation, the condition of the loop can span
3660 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
3661 // evaluate the condition.
3662 CFGBlock *ExitConditionBlock = createBlock(false);
3663 CFGBlock *EntryConditionBlock = ExitConditionBlock;
3665 // Set the terminator for the "exit" condition block.
3666 ExitConditionBlock->setTerminator(D);
3668 // Now add the actual condition to the condition block. Because the condition
3669 // itself may contain control-flow, new blocks may be created.
3670 if (Stmt *C = D->getCond()) {
3671 Block = ExitConditionBlock;
3672 EntryConditionBlock = addStmt(C);
3679 // The condition block is the implicit successor for the loop body.
3680 Succ = EntryConditionBlock;
3682 // See if this is a known constant.
3683 const TryResult &KnownVal = tryEvaluateBool(D->getCond());
3685 // Process the loop body.
3686 CFGBlock *BodyBlock = nullptr;
3688 assert(D->getBody());
3690 // Save the current values for Block, Succ, and continue and break targets
3691 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3692 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
3693 save_break(BreakJumpTarget);
3695 // All continues within this loop should go to the condition block
3696 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos);
3698 // All breaks should go to the code following the loop.
3699 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
3701 // NULL out Block to force lazy instantiation of blocks for the body.
3704 // If body is not a compound statement create implicit scope
3705 // and add destructors.
3706 if (!isa<CompoundStmt>(D->getBody()))
3707 addLocalScopeAndDtors(D->getBody());
3709 // Create the body. The returned block is the entry to the loop body.
3710 BodyBlock = addStmt(D->getBody());
3713 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)"
3719 // Add an intermediate block between the BodyBlock and the
3720 // ExitConditionBlock to represent the "loop back" transition. Create an
3721 // empty block to represent the transition block for looping back to the
3722 // head of the loop.
3723 // FIXME: Can we do this more efficiently without adding another block?
3726 CFGBlock *LoopBackBlock = createBlock();
3727 LoopBackBlock->setLoopTarget(D);
3729 if (!KnownVal.isFalse())
3730 // Add the loop body entry as a successor to the condition.
3731 addSuccessor(ExitConditionBlock, LoopBackBlock);
3733 addSuccessor(ExitConditionBlock, nullptr);
3736 // Link up the condition block with the code that follows the loop.
3737 // (the false branch).
3738 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
3740 // There can be no more statements in the body block(s) since we loop back to
3741 // the body. NULL out Block to force lazy creation of another block.
3744 // Return the loop body, which is the dominating block for the loop.
3749 CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) {
3750 // "continue" is a control-flow statement. Thus we stop processing the
3755 // Now create a new block that ends with the continue statement.
3756 Block = createBlock(false);
3757 Block->setTerminator(C);
3759 // If there is no target for the continue, then we are looking at an
3760 // incomplete AST. This means the CFG cannot be constructed.
3761 if (ContinueJumpTarget.block) {
3762 addAutomaticObjHandling(ScopePos, ContinueJumpTarget.scopePosition, C);
3763 addSuccessor(Block, ContinueJumpTarget.block);
3770 CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
3771 AddStmtChoice asc) {
3772 if (asc.alwaysAdd(*this, E)) {
3774 appendStmt(Block, E);
3777 // VLA types have expressions that must be evaluated.
3778 CFGBlock *lastBlock = Block;
3780 if (E->isArgumentType()) {
3781 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr());
3782 VA != nullptr; VA = FindVA(VA->getElementType().getTypePtr()))
3783 lastBlock = addStmt(VA->getSizeExpr());
3788 /// VisitStmtExpr - Utility method to handle (nested) statement
3789 /// expressions (a GCC extension).
3790 CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) {
3791 if (asc.alwaysAdd(*this, SE)) {
3793 appendStmt(Block, SE);
3795 return VisitCompoundStmt(SE->getSubStmt());
3798 CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) {
3799 // "switch" is a control-flow statement. Thus we stop processing the current
3801 CFGBlock *SwitchSuccessor = nullptr;
3803 // Save local scope position because in case of condition variable ScopePos
3804 // won't be restored when traversing AST.
3805 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
3807 // Create local scope for C++17 switch init-stmt if one exists.
3808 if (Stmt *Init = Terminator->getInit())
3809 addLocalScopeForStmt(Init);
3811 // Create local scope for possible condition variable.
3812 // Store scope position. Add implicit destructor.
3813 if (VarDecl *VD = Terminator->getConditionVariable())
3814 addLocalScopeForVarDecl(VD);
3816 addAutomaticObjHandling(ScopePos, save_scope_pos.get(), Terminator);
3821 SwitchSuccessor = Block;
3822 } else SwitchSuccessor = Succ;
3824 // Save the current "switch" context.
3825 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock),
3826 save_default(DefaultCaseBlock);
3827 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
3829 // Set the "default" case to be the block after the switch statement. If the
3830 // switch statement contains a "default:", this value will be overwritten with
3831 // the block for that code.
3832 DefaultCaseBlock = SwitchSuccessor;
3834 // Create a new block that will contain the switch statement.
3835 SwitchTerminatedBlock = createBlock(false);
3837 // Now process the switch body. The code after the switch is the implicit
3839 Succ = SwitchSuccessor;
3840 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos);
3842 // When visiting the body, the case statements should automatically get linked
3843 // up to the switch. We also don't keep a pointer to the body, since all
3844 // control-flow from the switch goes to case/default statements.
3845 assert(Terminator->getBody() && "switch must contain a non-NULL body");
3848 // For pruning unreachable case statements, save the current state
3849 // for tracking the condition value.
3850 SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered,
3853 // Determine if the switch condition can be explicitly evaluated.
3854 assert(Terminator->getCond() && "switch condition must be non-NULL");
3855 Expr::EvalResult result;
3856 bool b = tryEvaluate(Terminator->getCond(), result);
3857 SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond,
3858 b ? &result : nullptr);
3860 // If body is not a compound statement create implicit scope
3861 // and add destructors.
3862 if (!isa<CompoundStmt>(Terminator->getBody()))
3863 addLocalScopeAndDtors(Terminator->getBody());
3865 addStmt(Terminator->getBody());
3871 // If we have no "default:" case, the default transition is to the code
3872 // following the switch body. Moreover, take into account if all the
3873 // cases of a switch are covered (e.g., switching on an enum value).
3875 // Note: We add a successor to a switch that is considered covered yet has no
3876 // case statements if the enumeration has no enumerators.
3877 bool SwitchAlwaysHasSuccessor = false;
3878 SwitchAlwaysHasSuccessor |= switchExclusivelyCovered;
3879 SwitchAlwaysHasSuccessor |= Terminator->isAllEnumCasesCovered() &&
3880 Terminator->getSwitchCaseList();
3881 addSuccessor(SwitchTerminatedBlock, DefaultCaseBlock,
3882 !SwitchAlwaysHasSuccessor);
3884 // Add the terminator and condition in the switch block.
3885 SwitchTerminatedBlock->setTerminator(Terminator);
3886 Block = SwitchTerminatedBlock;
3887 CFGBlock *LastBlock = addStmt(Terminator->getCond());
3889 // If the SwitchStmt contains a condition variable, add both the
3890 // SwitchStmt and the condition variable initialization to the CFG.
3891 if (VarDecl *VD = Terminator->getConditionVariable()) {
3892 if (Expr *Init = VD->getInit()) {
3894 appendStmt(Block, Terminator->getConditionVariableDeclStmt());
3895 LastBlock = addStmt(Init);
3896 maybeAddScopeBeginForVarDecl(LastBlock, VD, Init);
3900 // Finally, if the SwitchStmt contains a C++17 init-stmt, add it to the CFG.
3901 if (Stmt *Init = Terminator->getInit()) {
3903 LastBlock = addStmt(Init);
3909 static bool shouldAddCase(bool &switchExclusivelyCovered,
3910 const Expr::EvalResult *switchCond,
3916 bool addCase = false;
3918 if (!switchExclusivelyCovered) {
3919 if (switchCond->Val.isInt()) {
3920 // Evaluate the LHS of the case value.
3921 const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx);
3922 const llvm::APSInt &condInt = switchCond->Val.getInt();
3924 if (condInt == lhsInt) {
3926 switchExclusivelyCovered = true;
3928 else if (condInt > lhsInt) {
3929 if (const Expr *RHS = CS->getRHS()) {
3930 // Evaluate the RHS of the case value.
3931 const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx);
3932 if (V2 >= condInt) {
3934 switchExclusivelyCovered = true;
3945 CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) {
3946 // CaseStmts are essentially labels, so they are the first statement in a
3948 CFGBlock *TopBlock = nullptr, *LastBlock = nullptr;
3950 if (Stmt *Sub = CS->getSubStmt()) {
3951 // For deeply nested chains of CaseStmts, instead of doing a recursion
3952 // (which can blow out the stack), manually unroll and create blocks
3954 while (isa<CaseStmt>(Sub)) {
3955 CFGBlock *currentBlock = createBlock(false);
3956 currentBlock->setLabel(CS);
3959 addSuccessor(LastBlock, currentBlock);
3961 TopBlock = currentBlock;
3963 addSuccessor(SwitchTerminatedBlock,
3964 shouldAddCase(switchExclusivelyCovered, switchCond,
3966 ? currentBlock : nullptr);
3968 LastBlock = currentBlock;
3969 CS = cast<CaseStmt>(Sub);
3970 Sub = CS->getSubStmt();
3976 CFGBlock *CaseBlock = Block;
3978 CaseBlock = createBlock();
3980 // Cases statements partition blocks, so this is the top of the basic block we
3981 // were processing (the "case XXX:" is the label).
3982 CaseBlock->setLabel(CS);
3987 // Add this block to the list of successors for the block with the switch
3989 assert(SwitchTerminatedBlock);
3990 addSuccessor(SwitchTerminatedBlock, CaseBlock,
3991 shouldAddCase(switchExclusivelyCovered, switchCond,
3994 // We set Block to NULL to allow lazy creation of a new block (if necessary)
3998 addSuccessor(LastBlock, CaseBlock);
4001 // This block is now the implicit successor of other blocks.
4008 CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) {
4009 if (Terminator->getSubStmt())
4010 addStmt(Terminator->getSubStmt());
4012 DefaultCaseBlock = Block;
4014 if (!DefaultCaseBlock)
4015 DefaultCaseBlock = createBlock();
4017 // Default statements partition blocks, so this is the top of the basic block
4018 // we were processing (the "default:" is the label).
4019 DefaultCaseBlock->setLabel(Terminator);
4024 // Unlike case statements, we don't add the default block to the successors
4025 // for the switch statement immediately. This is done when we finish
4026 // processing the switch statement. This allows for the default case
4027 // (including a fall-through to the code after the switch statement) to always
4028 // be the last successor of a switch-terminated block.
4030 // We set Block to NULL to allow lazy creation of a new block (if necessary)
4033 // This block is now the implicit successor of other blocks.
4034 Succ = DefaultCaseBlock;
4036 return DefaultCaseBlock;
4039 CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) {
4040 // "try"/"catch" is a control-flow statement. Thus we stop processing the
4042 CFGBlock *TrySuccessor = nullptr;
4047 TrySuccessor = Block;
4048 } else TrySuccessor = Succ;
4050 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock;
4052 // Create a new block that will contain the try statement.
4053 CFGBlock *NewTryTerminatedBlock = createBlock(false);
4054 // Add the terminator in the try block.
4055 NewTryTerminatedBlock->setTerminator(Terminator);
4057 bool HasCatchAll = false;
4058 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) {
4059 // The code after the try is the implicit successor.
4060 Succ = TrySuccessor;
4061 CXXCatchStmt *CS = Terminator->getHandler(h);
4062 if (CS->getExceptionDecl() == nullptr) {
4066 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS);
4069 // Add this block to the list of successors for the block with the try
4071 addSuccessor(NewTryTerminatedBlock, CatchBlock);
4074 if (PrevTryTerminatedBlock)
4075 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock);
4077 addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
4080 // The code after the try is the implicit successor.
4081 Succ = TrySuccessor;
4083 // Save the current "try" context.
4084 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock);
4085 cfg->addTryDispatchBlock(TryTerminatedBlock);
4087 assert(Terminator->getTryBlock() && "try must contain a non-NULL body");
4089 return addStmt(Terminator->getTryBlock());
4092 CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) {
4093 // CXXCatchStmt are treated like labels, so they are the first statement in a
4096 // Save local scope position because in case of exception variable ScopePos
4097 // won't be restored when traversing AST.
4098 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
4100 // Create local scope for possible exception variable.
4101 // Store scope position. Add implicit destructor.
4102 if (VarDecl *VD = CS->getExceptionDecl()) {
4103 LocalScope::const_iterator BeginScopePos = ScopePos;
4104 addLocalScopeForVarDecl(VD);
4105 addAutomaticObjHandling(ScopePos, BeginScopePos, CS);
4108 if (CS->getHandlerBlock())
4109 addStmt(CS->getHandlerBlock());
4111 CFGBlock *CatchBlock = Block;
4113 CatchBlock = createBlock();
4115 // CXXCatchStmt is more than just a label. They have semantic meaning
4116 // as well, as they implicitly "initialize" the catch variable. Add
4117 // it to the CFG as a CFGElement so that the control-flow of these
4118 // semantics gets captured.
4119 appendStmt(CatchBlock, CS);
4121 // Also add the CXXCatchStmt as a label, to mirror handling of regular
4123 CatchBlock->setLabel(CS);
4125 // Bail out if the CFG is bad.
4129 // We set Block to NULL to allow lazy creation of a new block (if necessary)
4135 CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) {
4136 // C++0x for-range statements are specified as [stmt.ranged]:
4139 // auto && __range = range-init;
4140 // for ( auto __begin = begin-expr,
4141 // __end = end-expr;
4142 // __begin != __end;
4144 // for-range-declaration = *__begin;
4149 // Save local scope position before the addition of the implicit variables.
4150 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
4152 // Create local scopes and destructors for range, begin and end variables.
4153 if (Stmt *Range = S->getRangeStmt())
4154 addLocalScopeForStmt(Range);
4155 if (Stmt *Begin = S->getBeginStmt())
4156 addLocalScopeForStmt(Begin);
4157 if (Stmt *End = S->getEndStmt())
4158 addLocalScopeForStmt(End);
4159 addAutomaticObjHandling(ScopePos, save_scope_pos.get(), S);
4161 LocalScope::const_iterator ContinueScopePos = ScopePos;
4163 // "for" is a control-flow statement. Thus we stop processing the current
4165 CFGBlock *LoopSuccessor = nullptr;
4169 LoopSuccessor = Block;
4171 LoopSuccessor = Succ;
4173 // Save the current value for the break targets.
4174 // All breaks should go to the code following the loop.
4175 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
4176 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
4178 // The block for the __begin != __end expression.
4179 CFGBlock *ConditionBlock = createBlock(false);
4180 ConditionBlock->setTerminator(S);
4182 // Now add the actual condition to the condition block.
4183 if (Expr *C = S->getCond()) {
4184 Block = ConditionBlock;
4185 CFGBlock *BeginConditionBlock = addStmt(C);
4188 assert(BeginConditionBlock == ConditionBlock &&
4189 "condition block in for-range was unexpectedly complex");
4190 (void)BeginConditionBlock;
4193 // The condition block is the implicit successor for the loop body as well as
4194 // any code above the loop.
4195 Succ = ConditionBlock;
4197 // See if this is a known constant.
4198 TryResult KnownVal(true);
4201 KnownVal = tryEvaluateBool(S->getCond());
4203 // Now create the loop body.
4205 assert(S->getBody());
4207 // Save the current values for Block, Succ, and continue targets.
4208 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
4209 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
4211 // Generate increment code in its own basic block. This is the target of
4212 // continue statements.
4214 Succ = addStmt(S->getInc());
4217 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
4219 // The starting block for the loop increment is the block that should
4220 // represent the 'loop target' for looping back to the start of the loop.
4221 ContinueJumpTarget.block->setLoopTarget(S);
4223 // Finish up the increment block and prepare to start the loop body.
4229 // Add implicit scope and dtors for loop variable.
4230 addLocalScopeAndDtors(S->getLoopVarStmt());
4232 // Populate a new block to contain the loop body and loop variable.
4233 addStmt(S->getBody());
4236 CFGBlock *LoopVarStmtBlock = addStmt(S->getLoopVarStmt());
4240 // This new body block is a successor to our condition block.
4241 addSuccessor(ConditionBlock,
4242 KnownVal.isFalse() ? nullptr : LoopVarStmtBlock);
4245 // Link up the condition block with the code that follows the loop (the
4247 addSuccessor(ConditionBlock, KnownVal.isTrue() ? nullptr : LoopSuccessor);
4249 // Add the initialization statements.
4250 Block = createBlock();
4251 addStmt(S->getBeginStmt());
4252 addStmt(S->getEndStmt());
4253 return addStmt(S->getRangeStmt());
4256 CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E,
4257 AddStmtChoice asc) {
4258 if (BuildOpts.AddTemporaryDtors) {
4259 // If adding implicit destructors visit the full expression for adding
4260 // destructors of temporaries.
4261 TempDtorContext Context;
4262 VisitForTemporaryDtors(E->getSubExpr(), false, Context);
4264 // Full expression has to be added as CFGStmt so it will be sequenced
4265 // before destructors of it's temporaries.
4266 asc = asc.withAlwaysAdd(true);
4268 return Visit(E->getSubExpr(), asc);
4271 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
4272 AddStmtChoice asc) {
4273 if (asc.alwaysAdd(*this, E)) {
4275 appendStmt(Block, E);
4277 findConstructionContexts(
4278 ConstructionContextLayer::create(cfg->getBumpVectorContext(), E),
4281 // We do not want to propagate the AlwaysAdd property.
4282 asc = asc.withAlwaysAdd(false);
4284 return Visit(E->getSubExpr(), asc);
4287 CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C,
4288 AddStmtChoice asc) {
4289 // If the constructor takes objects as arguments by value, we need to properly
4290 // construct these objects. Construction contexts we find here aren't for the
4291 // constructor C, they're for its arguments only.
4292 findConstructionContextsForArguments(C);
4295 appendConstructor(Block, C);
4297 return VisitChildren(C);
4300 CFGBlock *CFGBuilder::VisitCXXNewExpr(CXXNewExpr *NE,
4301 AddStmtChoice asc) {
4303 appendStmt(Block, NE);
4305 findConstructionContexts(
4306 ConstructionContextLayer::create(cfg->getBumpVectorContext(), NE),
4307 const_cast<CXXConstructExpr *>(NE->getConstructExpr()));
4309 if (NE->getInitializer())
4310 Block = Visit(NE->getInitializer());
4312 if (BuildOpts.AddCXXNewAllocator)
4313 appendNewAllocator(Block, NE);
4316 Block = Visit(NE->getArraySize());
4318 for (CXXNewExpr::arg_iterator I = NE->placement_arg_begin(),
4319 E = NE->placement_arg_end(); I != E; ++I)
4325 CFGBlock *CFGBuilder::VisitCXXDeleteExpr(CXXDeleteExpr *DE,
4326 AddStmtChoice asc) {
4328 appendStmt(Block, DE);
4329 QualType DTy = DE->getDestroyedType();
4330 if (!DTy.isNull()) {
4331 DTy = DTy.getNonReferenceType();
4332 CXXRecordDecl *RD = Context->getBaseElementType(DTy)->getAsCXXRecordDecl();
4334 if (RD->isCompleteDefinition() && !RD->hasTrivialDestructor())
4335 appendDeleteDtor(Block, RD, DE);
4339 return VisitChildren(DE);
4342 CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
4343 AddStmtChoice asc) {
4344 if (asc.alwaysAdd(*this, E)) {
4346 appendStmt(Block, E);
4347 // We do not want to propagate the AlwaysAdd property.
4348 asc = asc.withAlwaysAdd(false);
4350 return Visit(E->getSubExpr(), asc);
4353 CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
4354 AddStmtChoice asc) {
4356 appendConstructor(Block, C);
4357 return VisitChildren(C);
4360 CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E,
4361 AddStmtChoice asc) {
4362 if (asc.alwaysAdd(*this, E)) {
4364 appendStmt(Block, E);
4366 return Visit(E->getSubExpr(), AddStmtChoice());
4369 CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) {
4370 // Lazily create the indirect-goto dispatch block if there isn't one already.
4371 CFGBlock *IBlock = cfg->getIndirectGotoBlock();
4374 IBlock = createBlock(false);
4375 cfg->setIndirectGotoBlock(IBlock);
4378 // IndirectGoto is a control-flow statement. Thus we stop processing the
4379 // current block and create a new one.
4383 Block = createBlock(false);
4384 Block->setTerminator(I);
4385 addSuccessor(Block, IBlock);
4386 return addStmt(I->getTarget());
4389 CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary,
4390 TempDtorContext &Context) {
4391 assert(BuildOpts.AddImplicitDtors && BuildOpts.AddTemporaryDtors);
4398 switch (E->getStmtClass()) {
4400 return VisitChildrenForTemporaryDtors(E, Context);
4402 case Stmt::BinaryOperatorClass:
4403 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E),
4406 case Stmt::CXXBindTemporaryExprClass:
4407 return VisitCXXBindTemporaryExprForTemporaryDtors(
4408 cast<CXXBindTemporaryExpr>(E), BindToTemporary, Context);
4410 case Stmt::BinaryConditionalOperatorClass:
4411 case Stmt::ConditionalOperatorClass:
4412 return VisitConditionalOperatorForTemporaryDtors(
4413 cast<AbstractConditionalOperator>(E), BindToTemporary, Context);
4415 case Stmt::ImplicitCastExprClass:
4416 // For implicit cast we want BindToTemporary to be passed further.
4417 E = cast<CastExpr>(E)->getSubExpr();
4420 case Stmt::CXXFunctionalCastExprClass:
4421 // For functional cast we want BindToTemporary to be passed further.
4422 E = cast<CXXFunctionalCastExpr>(E)->getSubExpr();
4425 case Stmt::ParenExprClass:
4426 E = cast<ParenExpr>(E)->getSubExpr();
4429 case Stmt::MaterializeTemporaryExprClass: {
4430 const MaterializeTemporaryExpr* MTE = cast<MaterializeTemporaryExpr>(E);
4431 BindToTemporary = (MTE->getStorageDuration() != SD_FullExpression);
4432 SmallVector<const Expr *, 2> CommaLHSs;
4433 SmallVector<SubobjectAdjustment, 2> Adjustments;
4434 // Find the expression whose lifetime needs to be extended.
4435 E = const_cast<Expr *>(
4436 cast<MaterializeTemporaryExpr>(E)
4437 ->GetTemporaryExpr()
4438 ->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments));
4439 // Visit the skipped comma operator left-hand sides for other temporaries.
4440 for (const Expr *CommaLHS : CommaLHSs) {
4441 VisitForTemporaryDtors(const_cast<Expr *>(CommaLHS),
4442 /*BindToTemporary=*/false, Context);
4447 case Stmt::BlockExprClass:
4448 // Don't recurse into blocks; their subexpressions don't get evaluated
4452 case Stmt::LambdaExprClass: {
4453 // For lambda expressions, only recurse into the capture initializers,
4454 // and not the body.
4455 auto *LE = cast<LambdaExpr>(E);
4456 CFGBlock *B = Block;
4457 for (Expr *Init : LE->capture_inits()) {
4459 if (CFGBlock *R = VisitForTemporaryDtors(
4460 Init, /*BindToTemporary=*/false, Context))
4467 case Stmt::CXXDefaultArgExprClass:
4468 E = cast<CXXDefaultArgExpr>(E)->getExpr();
4471 case Stmt::CXXDefaultInitExprClass:
4472 E = cast<CXXDefaultInitExpr>(E)->getExpr();
4477 CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E,
4478 TempDtorContext &Context) {
4479 if (isa<LambdaExpr>(E)) {
4480 // Do not visit the children of lambdas; they have their own CFGs.
4484 // When visiting children for destructors we want to visit them in reverse
4485 // order that they will appear in the CFG. Because the CFG is built
4486 // bottom-up, this means we visit them in their natural order, which
4487 // reverses them in the CFG.
4488 CFGBlock *B = Block;
4489 for (Stmt *Child : E->children())
4491 if (CFGBlock *R = VisitForTemporaryDtors(Child, false, Context))
4497 CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(
4498 BinaryOperator *E, TempDtorContext &Context) {
4499 if (E->isLogicalOp()) {
4500 VisitForTemporaryDtors(E->getLHS(), false, Context);
4501 TryResult RHSExecuted = tryEvaluateBool(E->getLHS());
4502 if (RHSExecuted.isKnown() && E->getOpcode() == BO_LOr)
4503 RHSExecuted.negate();
4505 // We do not know at CFG-construction time whether the right-hand-side was
4506 // executed, thus we add a branch node that depends on the temporary
4507 // constructor call.
4508 TempDtorContext RHSContext(
4509 bothKnownTrue(Context.KnownExecuted, RHSExecuted));
4510 VisitForTemporaryDtors(E->getRHS(), false, RHSContext);
4511 InsertTempDtorDecisionBlock(RHSContext);
4516 if (E->isAssignmentOp()) {
4517 // For assignment operator (=) LHS expression is visited
4518 // before RHS expression. For destructors visit them in reverse order.
4519 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
4520 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
4521 return LHSBlock ? LHSBlock : RHSBlock;
4524 // For any other binary operator RHS expression is visited before
4525 // LHS expression (order of children). For destructors visit them in reverse
4527 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS(), false, Context);
4528 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), false, Context);
4529 return RHSBlock ? RHSBlock : LHSBlock;
4532 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors(
4533 CXXBindTemporaryExpr *E, bool BindToTemporary, TempDtorContext &Context) {
4534 // First add destructors for temporaries in subexpression.
4535 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr(), false, Context);
4536 if (!BindToTemporary) {
4537 // If lifetime of temporary is not prolonged (by assigning to constant
4538 // reference) add destructor for it.
4540 const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor();
4542 if (Dtor->getParent()->isAnyDestructorNoReturn()) {
4543 // If the destructor is marked as a no-return destructor, we need to
4544 // create a new block for the destructor which does not have as a
4545 // successor anything built thus far. Control won't flow out of this
4548 Block = createNoReturnBlock();
4549 } else if (Context.needsTempDtorBranch()) {
4550 // If we need to introduce a branch, we add a new block that we will hook
4551 // up to a decision block later.
4553 Block = createBlock();
4557 if (Context.needsTempDtorBranch()) {
4558 Context.setDecisionPoint(Succ, E);
4560 appendTemporaryDtor(Block, E);
4567 void CFGBuilder::InsertTempDtorDecisionBlock(const TempDtorContext &Context,
4568 CFGBlock *FalseSucc) {
4569 if (!Context.TerminatorExpr) {
4570 // If no temporary was found, we do not need to insert a decision point.
4573 assert(Context.TerminatorExpr);
4574 CFGBlock *Decision = createBlock(false);
4575 Decision->setTerminator(CFGTerminator(Context.TerminatorExpr, true));
4576 addSuccessor(Decision, Block, !Context.KnownExecuted.isFalse());
4577 addSuccessor(Decision, FalseSucc ? FalseSucc : Context.Succ,
4578 !Context.KnownExecuted.isTrue());
4582 CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors(
4583 AbstractConditionalOperator *E, bool BindToTemporary,
4584 TempDtorContext &Context) {
4585 VisitForTemporaryDtors(E->getCond(), false, Context);
4586 CFGBlock *ConditionBlock = Block;
4587 CFGBlock *ConditionSucc = Succ;
4588 TryResult ConditionVal = tryEvaluateBool(E->getCond());
4589 TryResult NegatedVal = ConditionVal;
4590 if (NegatedVal.isKnown()) NegatedVal.negate();
4592 TempDtorContext TrueContext(
4593 bothKnownTrue(Context.KnownExecuted, ConditionVal));
4594 VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary, TrueContext);
4595 CFGBlock *TrueBlock = Block;
4597 Block = ConditionBlock;
4598 Succ = ConditionSucc;
4599 TempDtorContext FalseContext(
4600 bothKnownTrue(Context.KnownExecuted, NegatedVal));
4601 VisitForTemporaryDtors(E->getFalseExpr(), BindToTemporary, FalseContext);
4603 if (TrueContext.TerminatorExpr && FalseContext.TerminatorExpr) {
4604 InsertTempDtorDecisionBlock(FalseContext, TrueBlock);
4605 } else if (TrueContext.TerminatorExpr) {
4607 InsertTempDtorDecisionBlock(TrueContext);
4609 InsertTempDtorDecisionBlock(FalseContext);
4614 /// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has
4615 /// no successors or predecessors. If this is the first block created in the
4616 /// CFG, it is automatically set to be the Entry and Exit of the CFG.
4617 CFGBlock *CFG::createBlock() {
4618 bool first_block = begin() == end();
4620 // Create the block.
4621 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>();
4622 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this);
4623 Blocks.push_back(Mem, BlkBVC);
4625 // If this is the first block, set it as the Entry and Exit.
4627 Entry = Exit = &back();
4629 // Return the block.
4633 /// buildCFG - Constructs a CFG from an AST.
4634 std::unique_ptr<CFG> CFG::buildCFG(const Decl *D, Stmt *Statement,
4635 ASTContext *C, const BuildOptions &BO) {
4636 CFGBuilder Builder(C, BO);
4637 return Builder.buildCFG(D, Statement);
4640 const CXXDestructorDecl *
4641 CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const {
4642 switch (getKind()) {
4643 case CFGElement::Initializer:
4644 case CFGElement::NewAllocator:
4645 case CFGElement::LoopExit:
4646 case CFGElement::LifetimeEnds:
4647 case CFGElement::Statement:
4648 case CFGElement::Constructor:
4649 case CFGElement::CXXRecordTypedCall:
4650 case CFGElement::ScopeBegin:
4651 case CFGElement::ScopeEnd:
4652 llvm_unreachable("getDestructorDecl should only be used with "
4654 case CFGElement::AutomaticObjectDtor: {
4655 const VarDecl *var = castAs<CFGAutomaticObjDtor>().getVarDecl();
4656 QualType ty = var->getType();
4658 // FIXME: See CFGBuilder::addLocalScopeForVarDecl.
4660 // Lifetime-extending constructs are handled here. This works for a single
4661 // temporary in an initializer expression.
4662 if (ty->isReferenceType()) {
4663 if (const Expr *Init = var->getInit()) {
4664 ty = getReferenceInitTemporaryType(Init);
4668 while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) {
4669 ty = arrayType->getElementType();
4671 const RecordType *recordType = ty->getAs<RecordType>();
4672 const CXXRecordDecl *classDecl =
4673 cast<CXXRecordDecl>(recordType->getDecl());
4674 return classDecl->getDestructor();
4676 case CFGElement::DeleteDtor: {
4677 const CXXDeleteExpr *DE = castAs<CFGDeleteDtor>().getDeleteExpr();
4678 QualType DTy = DE->getDestroyedType();
4679 DTy = DTy.getNonReferenceType();
4680 const CXXRecordDecl *classDecl =
4681 astContext.getBaseElementType(DTy)->getAsCXXRecordDecl();
4682 return classDecl->getDestructor();
4684 case CFGElement::TemporaryDtor: {
4685 const CXXBindTemporaryExpr *bindExpr =
4686 castAs<CFGTemporaryDtor>().getBindTemporaryExpr();
4687 const CXXTemporary *temp = bindExpr->getTemporary();
4688 return temp->getDestructor();
4690 case CFGElement::BaseDtor:
4691 case CFGElement::MemberDtor:
4692 // Not yet supported.
4695 llvm_unreachable("getKind() returned bogus value");
4698 bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const {
4699 if (const CXXDestructorDecl *DD = getDestructorDecl(astContext))
4700 return DD->isNoReturn();
4704 //===----------------------------------------------------------------------===//
4705 // CFGBlock operations.
4706 //===----------------------------------------------------------------------===//
4708 CFGBlock::AdjacentBlock::AdjacentBlock(CFGBlock *B, bool IsReachable)
4709 : ReachableBlock(IsReachable ? B : nullptr),
4710 UnreachableBlock(!IsReachable ? B : nullptr,
4711 B && IsReachable ? AB_Normal : AB_Unreachable) {}
4713 CFGBlock::AdjacentBlock::AdjacentBlock(CFGBlock *B, CFGBlock *AlternateBlock)
4714 : ReachableBlock(B),
4715 UnreachableBlock(B == AlternateBlock ? nullptr : AlternateBlock,
4716 B == AlternateBlock ? AB_Alternate : AB_Normal) {}
4718 void CFGBlock::addSuccessor(AdjacentBlock Succ,
4719 BumpVectorContext &C) {
4720 if (CFGBlock *B = Succ.getReachableBlock())
4721 B->Preds.push_back(AdjacentBlock(this, Succ.isReachable()), C);
4723 if (CFGBlock *UnreachableB = Succ.getPossiblyUnreachableBlock())
4724 UnreachableB->Preds.push_back(AdjacentBlock(this, false), C);
4726 Succs.push_back(Succ, C);
4729 bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F,
4730 const CFGBlock *From, const CFGBlock *To) {
4731 if (F.IgnoreNullPredecessors && !From)
4734 if (To && From && F.IgnoreDefaultsWithCoveredEnums) {
4735 // If the 'To' has no label or is labeled but the label isn't a
4736 // CaseStmt then filter this edge.
4737 if (const SwitchStmt *S =
4738 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) {
4739 if (S->isAllEnumCasesCovered()) {
4740 const Stmt *L = To->getLabel();
4741 if (!L || !isa<CaseStmt>(L))
4750 //===----------------------------------------------------------------------===//
4751 // CFG pretty printing
4752 //===----------------------------------------------------------------------===//
4756 class StmtPrinterHelper : public PrinterHelper {
4757 using StmtMapTy = llvm::DenseMap<const Stmt *, std::pair<unsigned, unsigned>>;
4758 using DeclMapTy = llvm::DenseMap<const Decl *, std::pair<unsigned, unsigned>>;
4762 signed currentBlock = 0;
4763 unsigned currStmt = 0;
4764 const LangOptions &LangOpts;
4767 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO)
4769 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) {
4771 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ;
4772 BI != BEnd; ++BI, ++j ) {
4773 if (Optional<CFGStmt> SE = BI->getAs<CFGStmt>()) {
4774 const Stmt *stmt= SE->getStmt();
4775 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j);
4778 switch (stmt->getStmtClass()) {
4779 case Stmt::DeclStmtClass:
4780 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P;
4782 case Stmt::IfStmtClass: {
4783 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable();
4788 case Stmt::ForStmtClass: {
4789 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable();
4794 case Stmt::WhileStmtClass: {
4795 const VarDecl *var =
4796 cast<WhileStmt>(stmt)->getConditionVariable();
4801 case Stmt::SwitchStmtClass: {
4802 const VarDecl *var =
4803 cast<SwitchStmt>(stmt)->getConditionVariable();
4808 case Stmt::CXXCatchStmtClass: {
4809 const VarDecl *var =
4810 cast<CXXCatchStmt>(stmt)->getExceptionDecl();
4823 ~StmtPrinterHelper() override = default;
4825 const LangOptions &getLangOpts() const { return LangOpts; }
4826 void setBlockID(signed i) { currentBlock = i; }
4827 void setStmtID(unsigned i) { currStmt = i; }
4829 bool handledStmt(Stmt *S, raw_ostream &OS) override {
4830 StmtMapTy::iterator I = StmtMap.find(S);
4832 if (I == StmtMap.end())
4835 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
4836 && I->second.second == currStmt) {
4840 OS << "[B" << I->second.first << "." << I->second.second << "]";
4844 bool handleDecl(const Decl *D, raw_ostream &OS) {
4845 DeclMapTy::iterator I = DeclMap.find(D);
4847 if (I == DeclMap.end())
4850 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
4851 && I->second.second == currStmt) {
4855 OS << "[B" << I->second.first << "." << I->second.second << "]";
4860 class CFGBlockTerminatorPrint
4861 : public StmtVisitor<CFGBlockTerminatorPrint,void> {
4863 StmtPrinterHelper* Helper;
4864 PrintingPolicy Policy;
4867 CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper,
4868 const PrintingPolicy &Policy)
4869 : OS(os), Helper(helper), Policy(Policy) {
4870 this->Policy.IncludeNewlines = false;
4873 void VisitIfStmt(IfStmt *I) {
4875 if (Stmt *C = I->getCond())
4876 C->printPretty(OS, Helper, Policy);
4880 void VisitStmt(Stmt *Terminator) {
4881 Terminator->printPretty(OS, Helper, Policy);
4884 void VisitDeclStmt(DeclStmt *DS) {
4885 VarDecl *VD = cast<VarDecl>(DS->getSingleDecl());
4886 OS << "static init " << VD->getName();
4889 void VisitForStmt(ForStmt *F) {
4894 if (Stmt *C = F->getCond())
4895 C->printPretty(OS, Helper, Policy);
4902 void VisitWhileStmt(WhileStmt *W) {
4904 if (Stmt *C = W->getCond())
4905 C->printPretty(OS, Helper, Policy);
4908 void VisitDoStmt(DoStmt *D) {
4909 OS << "do ... while ";
4910 if (Stmt *C = D->getCond())
4911 C->printPretty(OS, Helper, Policy);
4914 void VisitSwitchStmt(SwitchStmt *Terminator) {
4916 Terminator->getCond()->printPretty(OS, Helper, Policy);
4919 void VisitCXXTryStmt(CXXTryStmt *CS) {
4923 void VisitSEHTryStmt(SEHTryStmt *CS) {
4927 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) {
4928 if (Stmt *Cond = C->getCond())
4929 Cond->printPretty(OS, Helper, Policy);
4930 OS << " ? ... : ...";
4933 void VisitChooseExpr(ChooseExpr *C) {
4934 OS << "__builtin_choose_expr( ";
4935 if (Stmt *Cond = C->getCond())
4936 Cond->printPretty(OS, Helper, Policy);
4940 void VisitIndirectGotoStmt(IndirectGotoStmt *I) {
4942 if (Stmt *T = I->getTarget())
4943 T->printPretty(OS, Helper, Policy);
4946 void VisitBinaryOperator(BinaryOperator* B) {
4947 if (!B->isLogicalOp()) {
4953 B->getLHS()->printPretty(OS, Helper, Policy);
4955 switch (B->getOpcode()) {
4963 llvm_unreachable("Invalid logical operator.");
4967 void VisitExpr(Expr *E) {
4968 E->printPretty(OS, Helper, Policy);
4972 void print(CFGTerminator T) {
4973 if (T.isTemporaryDtorsBranch())
4974 OS << "(Temp Dtor) ";
4981 static void print_initializer(raw_ostream &OS, StmtPrinterHelper &Helper,
4982 const CXXCtorInitializer *I) {
4983 if (I->isBaseInitializer())
4984 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName();
4985 else if (I->isDelegatingInitializer())
4986 OS << I->getTypeSourceInfo()->getType()->getAsCXXRecordDecl()->getName();
4988 OS << I->getAnyMember()->getName();
4990 if (Expr *IE = I->getInit())
4991 IE->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
4994 if (I->isBaseInitializer())
4995 OS << " (Base initializer)";
4996 else if (I->isDelegatingInitializer())
4997 OS << " (Delegating initializer)";
4999 OS << " (Member initializer)";
5002 static void print_construction_context(raw_ostream &OS,
5003 StmtPrinterHelper &Helper,
5004 const ConstructionContext *CC) {
5005 SmallVector<const Stmt *, 3> Stmts;
5006 switch (CC->getKind()) {
5007 case ConstructionContext::SimpleConstructorInitializerKind: {
5009 const auto *SICC = cast<SimpleConstructorInitializerConstructionContext>(CC);
5010 print_initializer(OS, Helper, SICC->getCXXCtorInitializer());
5013 case ConstructionContext::CXX17ElidedCopyConstructorInitializerKind: {
5016 cast<CXX17ElidedCopyConstructorInitializerConstructionContext>(CC);
5017 print_initializer(OS, Helper, CICC->getCXXCtorInitializer());
5018 Stmts.push_back(CICC->getCXXBindTemporaryExpr());
5021 case ConstructionContext::SimpleVariableKind: {
5022 const auto *SDSCC = cast<SimpleVariableConstructionContext>(CC);
5023 Stmts.push_back(SDSCC->getDeclStmt());
5026 case ConstructionContext::CXX17ElidedCopyVariableKind: {
5027 const auto *CDSCC = cast<CXX17ElidedCopyVariableConstructionContext>(CC);
5028 Stmts.push_back(CDSCC->getDeclStmt());
5029 Stmts.push_back(CDSCC->getCXXBindTemporaryExpr());
5032 case ConstructionContext::NewAllocatedObjectKind: {
5033 const auto *NECC = cast<NewAllocatedObjectConstructionContext>(CC);
5034 Stmts.push_back(NECC->getCXXNewExpr());
5037 case ConstructionContext::SimpleReturnedValueKind: {
5038 const auto *RSCC = cast<SimpleReturnedValueConstructionContext>(CC);
5039 Stmts.push_back(RSCC->getReturnStmt());
5042 case ConstructionContext::CXX17ElidedCopyReturnedValueKind: {
5044 cast<CXX17ElidedCopyReturnedValueConstructionContext>(CC);
5045 Stmts.push_back(RSCC->getReturnStmt());
5046 Stmts.push_back(RSCC->getCXXBindTemporaryExpr());
5049 case ConstructionContext::SimpleTemporaryObjectKind: {
5050 const auto *TOCC = cast<SimpleTemporaryObjectConstructionContext>(CC);
5051 Stmts.push_back(TOCC->getCXXBindTemporaryExpr());
5052 Stmts.push_back(TOCC->getMaterializedTemporaryExpr());
5055 case ConstructionContext::ElidedTemporaryObjectKind: {
5056 const auto *TOCC = cast<ElidedTemporaryObjectConstructionContext>(CC);
5057 Stmts.push_back(TOCC->getCXXBindTemporaryExpr());
5058 Stmts.push_back(TOCC->getMaterializedTemporaryExpr());
5059 Stmts.push_back(TOCC->getConstructorAfterElision());
5062 case ConstructionContext::ArgumentKind: {
5063 const auto *ACC = cast<ArgumentConstructionContext>(CC);
5064 if (const Stmt *BTE = ACC->getCXXBindTemporaryExpr()) {
5066 Helper.handledStmt(const_cast<Stmt *>(BTE), OS);
5069 Helper.handledStmt(const_cast<Expr *>(ACC->getCallLikeExpr()), OS);
5070 OS << "+" << ACC->getIndex();
5077 Helper.handledStmt(const_cast<Stmt *>(I), OS);
5081 static void print_elem(raw_ostream &OS, StmtPrinterHelper &Helper,
5082 const CFGElement &E) {
5083 if (Optional<CFGStmt> CS = E.getAs<CFGStmt>()) {
5084 const Stmt *S = CS->getStmt();
5085 assert(S != nullptr && "Expecting non-null Stmt");
5087 // special printing for statement-expressions.
5088 if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) {
5089 const CompoundStmt *Sub = SE->getSubStmt();
5091 auto Children = Sub->children();
5092 if (Children.begin() != Children.end()) {
5094 Helper.handledStmt(*SE->getSubStmt()->body_rbegin(),OS);
5099 // special printing for comma expressions.
5100 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) {
5101 if (B->getOpcode() == BO_Comma) {
5103 Helper.handledStmt(B->getRHS(),OS);
5108 S->printPretty(OS, &Helper, PrintingPolicy(Helper.getLangOpts()));
5110 if (auto VTC = E.getAs<CFGCXXRecordTypedCall>()) {
5111 if (isa<CXXOperatorCallExpr>(S))
5112 OS << " (OperatorCall)";
5113 OS << " (CXXRecordTypedCall";
5114 print_construction_context(OS, Helper, VTC->getConstructionContext());
5116 } else if (isa<CXXOperatorCallExpr>(S)) {
5117 OS << " (OperatorCall)";
5118 } else if (isa<CXXBindTemporaryExpr>(S)) {
5119 OS << " (BindTemporary)";
5120 } else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) {
5121 OS << " (CXXConstructExpr";
5122 if (Optional<CFGConstructor> CE = E.getAs<CFGConstructor>()) {
5123 print_construction_context(OS, Helper, CE->getConstructionContext());
5125 OS << ", " << CCE->getType().getAsString() << ")";
5126 } else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) {
5127 OS << " (" << CE->getStmtClassName() << ", "
5128 << CE->getCastKindName()
5129 << ", " << CE->getType().getAsString()
5133 // Expressions need a newline.
5136 } else if (Optional<CFGInitializer> IE = E.getAs<CFGInitializer>()) {
5137 print_initializer(OS, Helper, IE->getInitializer());
5139 } else if (Optional<CFGAutomaticObjDtor> DE =
5140 E.getAs<CFGAutomaticObjDtor>()) {
5141 const VarDecl *VD = DE->getVarDecl();
5142 Helper.handleDecl(VD, OS);
5144 ASTContext &ACtx = VD->getASTContext();
5145 QualType T = VD->getType();
5146 if (T->isReferenceType())
5147 T = getReferenceInitTemporaryType(VD->getInit(), nullptr);
5148 if (const ArrayType *AT = ACtx.getAsArrayType(T))
5149 T = ACtx.getBaseElementType(AT);
5151 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()";
5152 OS << " (Implicit destructor)\n";
5153 } else if (Optional<CFGLifetimeEnds> DE = E.getAs<CFGLifetimeEnds>()) {
5154 const VarDecl *VD = DE->getVarDecl();
5155 Helper.handleDecl(VD, OS);
5157 OS << " (Lifetime ends)\n";
5158 } else if (Optional<CFGLoopExit> LE = E.getAs<CFGLoopExit>()) {
5159 const Stmt *LoopStmt = LE->getLoopStmt();
5160 OS << LoopStmt->getStmtClassName() << " (LoopExit)\n";
5161 } else if (Optional<CFGScopeBegin> SB = E.getAs<CFGScopeBegin>()) {
5162 OS << "CFGScopeBegin(";
5163 if (const VarDecl *VD = SB->getVarDecl())
5164 OS << VD->getQualifiedNameAsString();
5166 } else if (Optional<CFGScopeEnd> SE = E.getAs<CFGScopeEnd>()) {
5167 OS << "CFGScopeEnd(";
5168 if (const VarDecl *VD = SE->getVarDecl())
5169 OS << VD->getQualifiedNameAsString();
5171 } else if (Optional<CFGNewAllocator> NE = E.getAs<CFGNewAllocator>()) {
5172 OS << "CFGNewAllocator(";
5173 if (const CXXNewExpr *AllocExpr = NE->getAllocatorExpr())
5174 AllocExpr->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
5176 } else if (Optional<CFGDeleteDtor> DE = E.getAs<CFGDeleteDtor>()) {
5177 const CXXRecordDecl *RD = DE->getCXXRecordDecl();
5180 CXXDeleteExpr *DelExpr =
5181 const_cast<CXXDeleteExpr*>(DE->getDeleteExpr());
5182 Helper.handledStmt(cast<Stmt>(DelExpr->getArgument()), OS);
5183 OS << "->~" << RD->getName().str() << "()";
5184 OS << " (Implicit destructor)\n";
5185 } else if (Optional<CFGBaseDtor> BE = E.getAs<CFGBaseDtor>()) {
5186 const CXXBaseSpecifier *BS = BE->getBaseSpecifier();
5187 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()";
5188 OS << " (Base object destructor)\n";
5189 } else if (Optional<CFGMemberDtor> ME = E.getAs<CFGMemberDtor>()) {
5190 const FieldDecl *FD = ME->getFieldDecl();
5191 const Type *T = FD->getType()->getBaseElementTypeUnsafe();
5192 OS << "this->" << FD->getName();
5193 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()";
5194 OS << " (Member object destructor)\n";
5195 } else if (Optional<CFGTemporaryDtor> TE = E.getAs<CFGTemporaryDtor>()) {
5196 const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr();
5198 BT->getType().print(OS, PrintingPolicy(Helper.getLangOpts()));
5199 OS << "() (Temporary object destructor)\n";
5203 static void print_block(raw_ostream &OS, const CFG* cfg,
5205 StmtPrinterHelper &Helper, bool print_edges,
5207 Helper.setBlockID(B.getBlockID());
5209 // Print the header.
5211 OS.changeColor(raw_ostream::YELLOW, true);
5213 OS << "\n [B" << B.getBlockID();
5215 if (&B == &cfg->getEntry())
5216 OS << " (ENTRY)]\n";
5217 else if (&B == &cfg->getExit())
5219 else if (&B == cfg->getIndirectGotoBlock())
5220 OS << " (INDIRECT GOTO DISPATCH)]\n";
5221 else if (B.hasNoReturnElement())
5222 OS << " (NORETURN)]\n";
5229 // Print the label of this block.
5230 if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) {
5234 if (LabelStmt *L = dyn_cast<LabelStmt>(Label))
5236 else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) {
5239 C->getLHS()->printPretty(OS, &Helper,
5240 PrintingPolicy(Helper.getLangOpts()));
5243 C->getRHS()->printPretty(OS, &Helper,
5244 PrintingPolicy(Helper.getLangOpts()));
5246 } else if (isa<DefaultStmt>(Label))
5248 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) {
5250 if (CS->getExceptionDecl())
5251 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper.getLangOpts()),
5256 } else if (SEHExceptStmt *ES = dyn_cast<SEHExceptStmt>(Label)) {
5258 ES->getFilterExpr()->printPretty(OS, &Helper,
5259 PrintingPolicy(Helper.getLangOpts()), 0);
5262 llvm_unreachable("Invalid label statement in CFGBlock.");
5267 // Iterate through the statements in the block and print them.
5270 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ;
5271 I != E ; ++I, ++j ) {
5272 // Print the statement # in the basic block and the statement itself.
5276 OS << llvm::format("%3d", j) << ": ";
5278 Helper.setStmtID(j);
5280 print_elem(OS, Helper, *I);
5283 // Print the terminator of this block.
5284 if (B.getTerminator()) {
5286 OS.changeColor(raw_ostream::GREEN);
5290 Helper.setBlockID(-1);
5292 PrintingPolicy PP(Helper.getLangOpts());
5293 CFGBlockTerminatorPrint TPrinter(OS, &Helper, PP);
5294 TPrinter.print(B.getTerminator());
5302 // Print the predecessors of this block.
5303 if (!B.pred_empty()) {
5304 const raw_ostream::Colors Color = raw_ostream::BLUE;
5306 OS.changeColor(Color);
5310 OS << '(' << B.pred_size() << "):";
5314 OS.changeColor(Color);
5316 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end();
5322 bool Reachable = true;
5325 B = I->getPossiblyUnreachableBlock();
5328 OS << " B" << B->getBlockID();
5330 OS << "(Unreachable)";
5339 // Print the successors of this block.
5340 if (!B.succ_empty()) {
5341 const raw_ostream::Colors Color = raw_ostream::MAGENTA;
5343 OS.changeColor(Color);
5347 OS << '(' << B.succ_size() << "):";
5351 OS.changeColor(Color);
5353 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end();
5360 bool Reachable = true;
5363 B = I->getPossiblyUnreachableBlock();
5367 OS << " B" << B->getBlockID();
5369 OS << "(Unreachable)";
5383 /// dump - A simple pretty printer of a CFG that outputs to stderr.
5384 void CFG::dump(const LangOptions &LO, bool ShowColors) const {
5385 print(llvm::errs(), LO, ShowColors);
5388 /// print - A simple pretty printer of a CFG that outputs to an ostream.
5389 void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const {
5390 StmtPrinterHelper Helper(this, LO);
5392 // Print the entry block.
5393 print_block(OS, this, getEntry(), Helper, true, ShowColors);
5395 // Iterate through the CFGBlocks and print them one by one.
5396 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) {
5397 // Skip the entry block, because we already printed it.
5398 if (&(**I) == &getEntry() || &(**I) == &getExit())
5401 print_block(OS, this, **I, Helper, true, ShowColors);
5404 // Print the exit block.
5405 print_block(OS, this, getExit(), Helper, true, ShowColors);
5410 /// dump - A simply pretty printer of a CFGBlock that outputs to stderr.
5411 void CFGBlock::dump(const CFG* cfg, const LangOptions &LO,
5412 bool ShowColors) const {
5413 print(llvm::errs(), cfg, LO, ShowColors);
5416 LLVM_DUMP_METHOD void CFGBlock::dump() const {
5417 dump(getParent(), LangOptions(), false);
5420 /// print - A simple pretty printer of a CFGBlock that outputs to an ostream.
5421 /// Generally this will only be called from CFG::print.
5422 void CFGBlock::print(raw_ostream &OS, const CFG* cfg,
5423 const LangOptions &LO, bool ShowColors) const {
5424 StmtPrinterHelper Helper(cfg, LO);
5425 print_block(OS, cfg, *this, Helper, true, ShowColors);
5429 /// printTerminator - A simple pretty printer of the terminator of a CFGBlock.
5430 void CFGBlock::printTerminator(raw_ostream &OS,
5431 const LangOptions &LO) const {
5432 CFGBlockTerminatorPrint TPrinter(OS, nullptr, PrintingPolicy(LO));
5433 TPrinter.print(getTerminator());
5436 Stmt *CFGBlock::getTerminatorCondition(bool StripParens) {
5437 Stmt *Terminator = this->Terminator;
5443 switch (Terminator->getStmtClass()) {
5447 case Stmt::CXXForRangeStmtClass:
5448 E = cast<CXXForRangeStmt>(Terminator)->getCond();
5451 case Stmt::ForStmtClass:
5452 E = cast<ForStmt>(Terminator)->getCond();
5455 case Stmt::WhileStmtClass:
5456 E = cast<WhileStmt>(Terminator)->getCond();
5459 case Stmt::DoStmtClass:
5460 E = cast<DoStmt>(Terminator)->getCond();
5463 case Stmt::IfStmtClass:
5464 E = cast<IfStmt>(Terminator)->getCond();
5467 case Stmt::ChooseExprClass:
5468 E = cast<ChooseExpr>(Terminator)->getCond();
5471 case Stmt::IndirectGotoStmtClass:
5472 E = cast<IndirectGotoStmt>(Terminator)->getTarget();
5475 case Stmt::SwitchStmtClass:
5476 E = cast<SwitchStmt>(Terminator)->getCond();
5479 case Stmt::BinaryConditionalOperatorClass:
5480 E = cast<BinaryConditionalOperator>(Terminator)->getCond();
5483 case Stmt::ConditionalOperatorClass:
5484 E = cast<ConditionalOperator>(Terminator)->getCond();
5487 case Stmt::BinaryOperatorClass: // '&&' and '||'
5488 E = cast<BinaryOperator>(Terminator)->getLHS();
5491 case Stmt::ObjCForCollectionStmtClass:
5498 return E ? E->IgnoreParens() : nullptr;
5501 //===----------------------------------------------------------------------===//
5502 // CFG Graphviz Visualization
5503 //===----------------------------------------------------------------------===//
5506 static StmtPrinterHelper* GraphHelper;
5509 void CFG::viewCFG(const LangOptions &LO) const {
5511 StmtPrinterHelper H(this, LO);
5513 llvm::ViewGraph(this,"CFG");
5514 GraphHelper = nullptr;
5521 struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits {
5522 DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
5524 static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) {
5526 std::string OutSStr;
5527 llvm::raw_string_ostream Out(OutSStr);
5528 print_block(Out,Graph, *Node, *GraphHelper, false, false);
5529 std::string& OutStr = Out.str();
5531 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
5533 // Process string output to make it nicer...
5534 for (unsigned i = 0; i != OutStr.length(); ++i)
5535 if (OutStr[i] == '\n') { // Left justify
5537 OutStr.insert(OutStr.begin()+i+1, 'l');