1 //===--- CFG.h - Classes for representing and building CFGs------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the CFG and CFGBuilder classes for representing and
11 // building Control-Flow Graphs (CFGs) from ASTs.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_CLANG_CFG_H
16 #define LLVM_CLANG_CFG_H
18 #include "clang/AST/Stmt.h"
19 #include "clang/Analysis/Support/BumpVector.h"
20 #include "clang/Basic/SourceLocation.h"
21 #include "llvm/ADT/DenseMap.h"
22 #include "llvm/ADT/GraphTraits.h"
23 #include "llvm/ADT/Optional.h"
24 #include "llvm/ADT/PointerIntPair.h"
25 #include "llvm/Support/Allocator.h"
26 #include "llvm/Support/Casting.h"
27 #include "llvm/Support/raw_ostream.h"
34 class CXXDestructorDecl;
40 class CXXCtorInitializer;
41 class CXXBaseSpecifier;
42 class CXXBindTemporaryExpr;
52 /// CFGElement - Represents a top-level expression in a basic block.
66 DTOR_BEGIN = AutomaticObjectDtor,
67 DTOR_END = TemporaryDtor
71 // The int bits are used to mark the kind.
72 llvm::PointerIntPair<void *, 2> Data1;
73 llvm::PointerIntPair<void *, 2> Data2;
75 CFGElement(Kind kind, const void *Ptr1, const void *Ptr2 = nullptr)
76 : Data1(const_cast<void*>(Ptr1), ((unsigned) kind) & 0x3),
77 Data2(const_cast<void*>(Ptr2), (((unsigned) kind) >> 2) & 0x3) {
78 assert(getKind() == kind);
84 /// \brief Convert to the specified CFGElement type, asserting that this
85 /// CFGElement is of the desired type.
88 assert(T::isKind(*this));
95 /// \brief Convert to the specified CFGElement type, returning None if this
96 /// CFGElement is not of the desired type.
98 Optional<T> getAs() const {
99 if (!T::isKind(*this))
107 Kind getKind() const {
108 unsigned x = Data2.getInt();
115 class CFGStmt : public CFGElement {
117 CFGStmt(Stmt *S) : CFGElement(Statement, S) {}
119 const Stmt *getStmt() const {
120 return static_cast<const Stmt *>(Data1.getPointer());
124 friend class CFGElement;
126 static bool isKind(const CFGElement &E) {
127 return E.getKind() == Statement;
131 /// CFGInitializer - Represents C++ base or member initializer from
132 /// constructor's initialization list.
133 class CFGInitializer : public CFGElement {
135 CFGInitializer(CXXCtorInitializer *initializer)
136 : CFGElement(Initializer, initializer) {}
138 CXXCtorInitializer* getInitializer() const {
139 return static_cast<CXXCtorInitializer*>(Data1.getPointer());
143 friend class CFGElement;
145 static bool isKind(const CFGElement &E) {
146 return E.getKind() == Initializer;
150 /// CFGNewAllocator - Represents C++ allocator call.
151 class CFGNewAllocator : public CFGElement {
153 explicit CFGNewAllocator(const CXXNewExpr *S)
154 : CFGElement(NewAllocator, S) {}
156 // Get the new expression.
157 const CXXNewExpr *getAllocatorExpr() const {
158 return static_cast<CXXNewExpr *>(Data1.getPointer());
162 friend class CFGElement;
164 static bool isKind(const CFGElement &elem) {
165 return elem.getKind() == NewAllocator;
169 /// CFGImplicitDtor - Represents C++ object destructor implicitly generated
170 /// by compiler on various occasions.
171 class CFGImplicitDtor : public CFGElement {
174 CFGImplicitDtor(Kind kind, const void *data1, const void *data2 = nullptr)
175 : CFGElement(kind, data1, data2) {
176 assert(kind >= DTOR_BEGIN && kind <= DTOR_END);
180 const CXXDestructorDecl *getDestructorDecl(ASTContext &astContext) const;
181 bool isNoReturn(ASTContext &astContext) const;
184 friend class CFGElement;
185 static bool isKind(const CFGElement &E) {
186 Kind kind = E.getKind();
187 return kind >= DTOR_BEGIN && kind <= DTOR_END;
191 /// CFGAutomaticObjDtor - Represents C++ object destructor implicitly generated
192 /// for automatic object or temporary bound to const reference at the point
193 /// of leaving its local scope.
194 class CFGAutomaticObjDtor: public CFGImplicitDtor {
196 CFGAutomaticObjDtor(const VarDecl *var, const Stmt *stmt)
197 : CFGImplicitDtor(AutomaticObjectDtor, var, stmt) {}
199 const VarDecl *getVarDecl() const {
200 return static_cast<VarDecl*>(Data1.getPointer());
203 // Get statement end of which triggered the destructor call.
204 const Stmt *getTriggerStmt() const {
205 return static_cast<Stmt*>(Data2.getPointer());
209 friend class CFGElement;
210 CFGAutomaticObjDtor() {}
211 static bool isKind(const CFGElement &elem) {
212 return elem.getKind() == AutomaticObjectDtor;
216 /// CFGDeleteDtor - Represents C++ object destructor generated
217 /// from a call to delete.
218 class CFGDeleteDtor : public CFGImplicitDtor {
220 CFGDeleteDtor(const CXXRecordDecl *RD, const CXXDeleteExpr *DE)
221 : CFGImplicitDtor(DeleteDtor, RD, DE) {}
223 const CXXRecordDecl *getCXXRecordDecl() const {
224 return static_cast<CXXRecordDecl*>(Data1.getPointer());
227 // Get Delete expression which triggered the destructor call.
228 const CXXDeleteExpr *getDeleteExpr() const {
229 return static_cast<CXXDeleteExpr *>(Data2.getPointer());
234 friend class CFGElement;
236 static bool isKind(const CFGElement &elem) {
237 return elem.getKind() == DeleteDtor;
241 /// CFGBaseDtor - Represents C++ object destructor implicitly generated for
242 /// base object in destructor.
243 class CFGBaseDtor : public CFGImplicitDtor {
245 CFGBaseDtor(const CXXBaseSpecifier *base)
246 : CFGImplicitDtor(BaseDtor, base) {}
248 const CXXBaseSpecifier *getBaseSpecifier() const {
249 return static_cast<const CXXBaseSpecifier*>(Data1.getPointer());
253 friend class CFGElement;
255 static bool isKind(const CFGElement &E) {
256 return E.getKind() == BaseDtor;
260 /// CFGMemberDtor - Represents C++ object destructor implicitly generated for
261 /// member object in destructor.
262 class CFGMemberDtor : public CFGImplicitDtor {
264 CFGMemberDtor(const FieldDecl *field)
265 : CFGImplicitDtor(MemberDtor, field, nullptr) {}
267 const FieldDecl *getFieldDecl() const {
268 return static_cast<const FieldDecl*>(Data1.getPointer());
272 friend class CFGElement;
274 static bool isKind(const CFGElement &E) {
275 return E.getKind() == MemberDtor;
279 /// CFGTemporaryDtor - Represents C++ object destructor implicitly generated
280 /// at the end of full expression for temporary object.
281 class CFGTemporaryDtor : public CFGImplicitDtor {
283 CFGTemporaryDtor(CXXBindTemporaryExpr *expr)
284 : CFGImplicitDtor(TemporaryDtor, expr, nullptr) {}
286 const CXXBindTemporaryExpr *getBindTemporaryExpr() const {
287 return static_cast<const CXXBindTemporaryExpr *>(Data1.getPointer());
291 friend class CFGElement;
292 CFGTemporaryDtor() {}
293 static bool isKind(const CFGElement &E) {
294 return E.getKind() == TemporaryDtor;
298 /// CFGTerminator - Represents CFGBlock terminator statement.
300 /// TemporaryDtorsBranch bit is set to true if the terminator marks a branch
301 /// in control flow of destructors of temporaries. In this case terminator
302 /// statement is the same statement that branches control flow in evaluation
303 /// of matching full expression.
304 class CFGTerminator {
305 llvm::PointerIntPair<Stmt *, 1> Data;
308 CFGTerminator(Stmt *S, bool TemporaryDtorsBranch = false)
309 : Data(S, TemporaryDtorsBranch) {}
311 Stmt *getStmt() { return Data.getPointer(); }
312 const Stmt *getStmt() const { return Data.getPointer(); }
314 bool isTemporaryDtorsBranch() const { return Data.getInt(); }
316 operator Stmt *() { return getStmt(); }
317 operator const Stmt *() const { return getStmt(); }
319 Stmt *operator->() { return getStmt(); }
320 const Stmt *operator->() const { return getStmt(); }
322 Stmt &operator*() { return *getStmt(); }
323 const Stmt &operator*() const { return *getStmt(); }
325 LLVM_EXPLICIT operator bool() const { return getStmt(); }
328 /// CFGBlock - Represents a single basic block in a source-level CFG.
331 /// (1) A set of statements/expressions (which may contain subexpressions).
332 /// (2) A "terminator" statement (not in the set of statements).
333 /// (3) A list of successors and predecessors.
335 /// Terminator: The terminator represents the type of control-flow that occurs
336 /// at the end of the basic block. The terminator is a Stmt* referring to an
337 /// AST node that has control-flow: if-statements, breaks, loops, etc.
338 /// If the control-flow is conditional, the condition expression will appear
339 /// within the set of statements in the block (usually the last statement).
341 /// Predecessors: the order in the set of predecessors is arbitrary.
343 /// Successors: the order in the set of successors is NOT arbitrary. We
344 /// currently have the following orderings based on the terminator:
346 /// Terminator Successor Ordering
347 /// -----------------------------------------------------
348 /// if Then Block; Else Block
349 /// ? operator LHS expression; RHS expression
350 /// &&, || expression that uses result of && or ||, RHS
352 /// But note that any of that may be NULL in case of optimized-out edges.
356 typedef BumpVector<CFGElement> ImplTy;
359 ElementList(BumpVectorContext &C) : Impl(C, 4) {}
361 typedef std::reverse_iterator<ImplTy::iterator> iterator;
362 typedef std::reverse_iterator<ImplTy::const_iterator> const_iterator;
363 typedef ImplTy::iterator reverse_iterator;
364 typedef ImplTy::const_iterator const_reverse_iterator;
365 typedef ImplTy::const_reference const_reference;
367 void push_back(CFGElement e, BumpVectorContext &C) { Impl.push_back(e, C); }
368 reverse_iterator insert(reverse_iterator I, size_t Cnt, CFGElement E,
369 BumpVectorContext &C) {
370 return Impl.insert(I, Cnt, E, C);
373 const_reference front() const { return Impl.back(); }
374 const_reference back() const { return Impl.front(); }
376 iterator begin() { return Impl.rbegin(); }
377 iterator end() { return Impl.rend(); }
378 const_iterator begin() const { return Impl.rbegin(); }
379 const_iterator end() const { return Impl.rend(); }
380 reverse_iterator rbegin() { return Impl.begin(); }
381 reverse_iterator rend() { return Impl.end(); }
382 const_reverse_iterator rbegin() const { return Impl.begin(); }
383 const_reverse_iterator rend() const { return Impl.end(); }
385 CFGElement operator[](size_t i) const {
386 assert(i < Impl.size());
387 return Impl[Impl.size() - 1 - i];
390 size_t size() const { return Impl.size(); }
391 bool empty() const { return Impl.empty(); }
394 /// Stmts - The set of statements in the basic block.
395 ElementList Elements;
397 /// Label - An (optional) label that prefixes the executable
398 /// statements in the block. When this variable is non-NULL, it is
399 /// either an instance of LabelStmt, SwitchCase or CXXCatchStmt.
402 /// Terminator - The terminator for a basic block that
403 /// indicates the type of control-flow that occurs between a block
404 /// and its successors.
405 CFGTerminator Terminator;
407 /// LoopTarget - Some blocks are used to represent the "loop edge" to
408 /// the start of a loop from within the loop body. This Stmt* will be
409 /// refer to the loop statement for such blocks (and be null otherwise).
410 const Stmt *LoopTarget;
412 /// BlockID - A numerical ID assigned to a CFGBlock during construction
417 /// This class represents a potential adjacent block in the CFG. It encodes
418 /// whether or not the block is actually reachable, or can be proved to be
419 /// trivially unreachable. For some cases it allows one to encode scenarios
420 /// where a block was substituted because the original (now alternate) block
422 class AdjacentBlock {
429 CFGBlock *ReachableBlock;
430 llvm::PointerIntPair<CFGBlock*, 2> UnreachableBlock;
433 /// Construct an AdjacentBlock with a possibly unreachable block.
434 AdjacentBlock(CFGBlock *B, bool IsReachable);
436 /// Construct an AdjacentBlock with a reachable block and an alternate
437 /// unreachable block.
438 AdjacentBlock(CFGBlock *B, CFGBlock *AlternateBlock);
440 /// Get the reachable block, if one exists.
441 CFGBlock *getReachableBlock() const {
442 return ReachableBlock;
445 /// Get the potentially unreachable block.
446 CFGBlock *getPossiblyUnreachableBlock() const {
447 return UnreachableBlock.getPointer();
450 /// Provide an implicit conversion to CFGBlock* so that
451 /// AdjacentBlock can be substituted for CFGBlock*.
452 operator CFGBlock*() const {
453 return getReachableBlock();
456 CFGBlock& operator *() const {
457 return *getReachableBlock();
460 CFGBlock* operator ->() const {
461 return getReachableBlock();
464 bool isReachable() const {
465 Kind K = (Kind) UnreachableBlock.getInt();
466 return K == AB_Normal || K == AB_Alternate;
471 /// Predecessors/Successors - Keep track of the predecessor / successor
473 typedef BumpVector<AdjacentBlock> AdjacentBlocks;
474 AdjacentBlocks Preds;
475 AdjacentBlocks Succs;
477 /// NoReturn - This bit is set when the basic block contains a function call
478 /// or implicit destructor that is attributed as 'noreturn'. In that case,
479 /// control cannot technically ever proceed past this block. All such blocks
480 /// will have a single immediate successor: the exit block. This allows them
481 /// to be easily reached from the exit block and using this bit quickly
482 /// recognized without scanning the contents of the block.
484 /// Optimization Note: This bit could be profitably folded with Terminator's
485 /// storage if the memory usage of CFGBlock becomes an issue.
486 unsigned HasNoReturnElement : 1;
488 /// Parent - The parent CFG that owns this CFGBlock.
492 explicit CFGBlock(unsigned blockid, BumpVectorContext &C, CFG *parent)
493 : Elements(C), Label(nullptr), Terminator(nullptr), LoopTarget(nullptr),
494 BlockID(blockid), Preds(C, 1), Succs(C, 1), HasNoReturnElement(false),
498 // Statement iterators
499 typedef ElementList::iterator iterator;
500 typedef ElementList::const_iterator const_iterator;
501 typedef ElementList::reverse_iterator reverse_iterator;
502 typedef ElementList::const_reverse_iterator const_reverse_iterator;
504 CFGElement front() const { return Elements.front(); }
505 CFGElement back() const { return Elements.back(); }
507 iterator begin() { return Elements.begin(); }
508 iterator end() { return Elements.end(); }
509 const_iterator begin() const { return Elements.begin(); }
510 const_iterator end() const { return Elements.end(); }
512 reverse_iterator rbegin() { return Elements.rbegin(); }
513 reverse_iterator rend() { return Elements.rend(); }
514 const_reverse_iterator rbegin() const { return Elements.rbegin(); }
515 const_reverse_iterator rend() const { return Elements.rend(); }
517 unsigned size() const { return Elements.size(); }
518 bool empty() const { return Elements.empty(); }
520 CFGElement operator[](size_t i) const { return Elements[i]; }
523 typedef AdjacentBlocks::iterator pred_iterator;
524 typedef AdjacentBlocks::const_iterator const_pred_iterator;
525 typedef AdjacentBlocks::reverse_iterator pred_reverse_iterator;
526 typedef AdjacentBlocks::const_reverse_iterator const_pred_reverse_iterator;
528 typedef AdjacentBlocks::iterator succ_iterator;
529 typedef AdjacentBlocks::const_iterator const_succ_iterator;
530 typedef AdjacentBlocks::reverse_iterator succ_reverse_iterator;
531 typedef AdjacentBlocks::const_reverse_iterator const_succ_reverse_iterator;
533 pred_iterator pred_begin() { return Preds.begin(); }
534 pred_iterator pred_end() { return Preds.end(); }
535 const_pred_iterator pred_begin() const { return Preds.begin(); }
536 const_pred_iterator pred_end() const { return Preds.end(); }
538 pred_reverse_iterator pred_rbegin() { return Preds.rbegin(); }
539 pred_reverse_iterator pred_rend() { return Preds.rend(); }
540 const_pred_reverse_iterator pred_rbegin() const { return Preds.rbegin(); }
541 const_pred_reverse_iterator pred_rend() const { return Preds.rend(); }
543 succ_iterator succ_begin() { return Succs.begin(); }
544 succ_iterator succ_end() { return Succs.end(); }
545 const_succ_iterator succ_begin() const { return Succs.begin(); }
546 const_succ_iterator succ_end() const { return Succs.end(); }
548 succ_reverse_iterator succ_rbegin() { return Succs.rbegin(); }
549 succ_reverse_iterator succ_rend() { return Succs.rend(); }
550 const_succ_reverse_iterator succ_rbegin() const { return Succs.rbegin(); }
551 const_succ_reverse_iterator succ_rend() const { return Succs.rend(); }
553 unsigned succ_size() const { return Succs.size(); }
554 bool succ_empty() const { return Succs.empty(); }
556 unsigned pred_size() const { return Preds.size(); }
557 bool pred_empty() const { return Preds.empty(); }
560 class FilterOptions {
563 IgnoreNullPredecessors = 1;
564 IgnoreDefaultsWithCoveredEnums = 0;
567 unsigned IgnoreNullPredecessors : 1;
568 unsigned IgnoreDefaultsWithCoveredEnums : 1;
571 static bool FilterEdge(const FilterOptions &F, const CFGBlock *Src,
572 const CFGBlock *Dst);
574 template <typename IMPL, bool IsPred>
575 class FilteredCFGBlockIterator {
578 const FilterOptions F;
579 const CFGBlock *From;
581 explicit FilteredCFGBlockIterator(const IMPL &i, const IMPL &e,
582 const CFGBlock *from,
583 const FilterOptions &f)
584 : I(i), E(e), F(f), From(from) {
585 while (hasMore() && Filter(*I))
589 bool hasMore() const { return I != E; }
591 FilteredCFGBlockIterator &operator++() {
592 do { ++I; } while (hasMore() && Filter(*I));
596 const CFGBlock *operator*() const { return *I; }
598 bool Filter(const CFGBlock *To) {
599 return IsPred ? FilterEdge(F, To, From) : FilterEdge(F, From, To);
603 typedef FilteredCFGBlockIterator<const_pred_iterator, true>
604 filtered_pred_iterator;
606 typedef FilteredCFGBlockIterator<const_succ_iterator, false>
607 filtered_succ_iterator;
609 filtered_pred_iterator filtered_pred_start_end(const FilterOptions &f) const {
610 return filtered_pred_iterator(pred_begin(), pred_end(), this, f);
613 filtered_succ_iterator filtered_succ_start_end(const FilterOptions &f) const {
614 return filtered_succ_iterator(succ_begin(), succ_end(), this, f);
617 // Manipulation of block contents
619 void setTerminator(CFGTerminator Term) { Terminator = Term; }
620 void setLabel(Stmt *Statement) { Label = Statement; }
621 void setLoopTarget(const Stmt *loopTarget) { LoopTarget = loopTarget; }
622 void setHasNoReturnElement() { HasNoReturnElement = true; }
624 CFGTerminator getTerminator() { return Terminator; }
625 const CFGTerminator getTerminator() const { return Terminator; }
627 Stmt *getTerminatorCondition(bool StripParens = true);
629 const Stmt *getTerminatorCondition(bool StripParens = true) const {
630 return const_cast<CFGBlock*>(this)->getTerminatorCondition(StripParens);
633 const Stmt *getLoopTarget() const { return LoopTarget; }
635 Stmt *getLabel() { return Label; }
636 const Stmt *getLabel() const { return Label; }
638 bool hasNoReturnElement() const { return HasNoReturnElement; }
640 unsigned getBlockID() const { return BlockID; }
642 CFG *getParent() const { return Parent; }
646 void dump(const CFG *cfg, const LangOptions &LO, bool ShowColors = false) const;
647 void print(raw_ostream &OS, const CFG* cfg, const LangOptions &LO,
648 bool ShowColors) const;
649 void printTerminator(raw_ostream &OS, const LangOptions &LO) const;
650 void printAsOperand(raw_ostream &OS, bool /*PrintType*/) {
651 OS << "BB#" << getBlockID();
654 /// Adds a (potentially unreachable) successor block to the current block.
655 void addSuccessor(AdjacentBlock Succ, BumpVectorContext &C);
657 void appendStmt(Stmt *statement, BumpVectorContext &C) {
658 Elements.push_back(CFGStmt(statement), C);
661 void appendInitializer(CXXCtorInitializer *initializer,
662 BumpVectorContext &C) {
663 Elements.push_back(CFGInitializer(initializer), C);
666 void appendNewAllocator(CXXNewExpr *NE,
667 BumpVectorContext &C) {
668 Elements.push_back(CFGNewAllocator(NE), C);
671 void appendBaseDtor(const CXXBaseSpecifier *BS, BumpVectorContext &C) {
672 Elements.push_back(CFGBaseDtor(BS), C);
675 void appendMemberDtor(FieldDecl *FD, BumpVectorContext &C) {
676 Elements.push_back(CFGMemberDtor(FD), C);
679 void appendTemporaryDtor(CXXBindTemporaryExpr *E, BumpVectorContext &C) {
680 Elements.push_back(CFGTemporaryDtor(E), C);
683 void appendAutomaticObjDtor(VarDecl *VD, Stmt *S, BumpVectorContext &C) {
684 Elements.push_back(CFGAutomaticObjDtor(VD, S), C);
687 void appendDeleteDtor(CXXRecordDecl *RD, CXXDeleteExpr *DE, BumpVectorContext &C) {
688 Elements.push_back(CFGDeleteDtor(RD, DE), C);
691 // Destructors must be inserted in reversed order. So insertion is in two
692 // steps. First we prepare space for some number of elements, then we insert
693 // the elements beginning at the last position in prepared space.
694 iterator beginAutomaticObjDtorsInsert(iterator I, size_t Cnt,
695 BumpVectorContext &C) {
696 return iterator(Elements.insert(I.base(), Cnt,
697 CFGAutomaticObjDtor(nullptr, 0), C));
699 iterator insertAutomaticObjDtor(iterator I, VarDecl *VD, Stmt *S) {
700 *I = CFGAutomaticObjDtor(VD, S);
705 /// \brief CFGCallback defines methods that should be called when a logical
706 /// operator error is found when building the CFG.
710 virtual void compareAlwaysTrue(const BinaryOperator *B, bool isAlwaysTrue) {}
711 virtual void compareBitwiseEquality(const BinaryOperator *B,
712 bool isAlwaysTrue) {}
713 virtual ~CFGCallback() {}
716 /// CFG - Represents a source-level, intra-procedural CFG that represents the
717 /// control-flow of a Stmt. The Stmt can represent an entire function body,
718 /// or a single expression. A CFG will always contain one empty block that
719 /// represents the Exit point of the CFG. A CFG will also contain a designated
720 /// Entry block. The CFG solely represents control-flow; it consists of
721 /// CFGBlocks which are simply containers of Stmt*'s in the AST the CFG
722 /// was constructed from.
725 //===--------------------------------------------------------------------===//
726 // CFG Construction & Manipulation.
727 //===--------------------------------------------------------------------===//
730 std::bitset<Stmt::lastStmtConstant> alwaysAddMask;
732 typedef llvm::DenseMap<const Stmt *, const CFGBlock*> ForcedBlkExprs;
733 ForcedBlkExprs **forcedBlkExprs;
734 CFGCallback *Observer;
735 bool PruneTriviallyFalseEdges;
737 bool AddInitializers;
738 bool AddImplicitDtors;
739 bool AddTemporaryDtors;
740 bool AddStaticInitBranches;
741 bool AddCXXNewAllocator;
743 bool alwaysAdd(const Stmt *stmt) const {
744 return alwaysAddMask[stmt->getStmtClass()];
747 BuildOptions &setAlwaysAdd(Stmt::StmtClass stmtClass, bool val = true) {
748 alwaysAddMask[stmtClass] = val;
752 BuildOptions &setAllAlwaysAdd() {
758 : forcedBlkExprs(nullptr), Observer(nullptr),
759 PruneTriviallyFalseEdges(true), AddEHEdges(false),
760 AddInitializers(false), AddImplicitDtors(false),
761 AddTemporaryDtors(false), AddStaticInitBranches(false),
762 AddCXXNewAllocator(false) {}
765 /// \brief Provides a custom implementation of the iterator class to have the
766 /// same interface as Function::iterator - iterator returns CFGBlock
767 /// (not a pointer to CFGBlock).
768 class graph_iterator {
770 typedef const CFGBlock value_type;
771 typedef value_type& reference;
772 typedef value_type* pointer;
773 typedef BumpVector<CFGBlock*>::iterator ImplTy;
775 graph_iterator(const ImplTy &i) : I(i) {}
777 bool operator==(const graph_iterator &X) const { return I == X.I; }
778 bool operator!=(const graph_iterator &X) const { return I != X.I; }
780 reference operator*() const { return **I; }
781 pointer operator->() const { return *I; }
782 operator CFGBlock* () { return *I; }
784 graph_iterator &operator++() { ++I; return *this; }
785 graph_iterator &operator--() { --I; return *this; }
791 class const_graph_iterator {
793 typedef const CFGBlock value_type;
794 typedef value_type& reference;
795 typedef value_type* pointer;
796 typedef BumpVector<CFGBlock*>::const_iterator ImplTy;
798 const_graph_iterator(const ImplTy &i) : I(i) {}
800 bool operator==(const const_graph_iterator &X) const { return I == X.I; }
801 bool operator!=(const const_graph_iterator &X) const { return I != X.I; }
803 reference operator*() const { return **I; }
804 pointer operator->() const { return *I; }
805 operator CFGBlock* () const { return *I; }
807 const_graph_iterator &operator++() { ++I; return *this; }
808 const_graph_iterator &operator--() { --I; return *this; }
814 /// buildCFG - Builds a CFG from an AST. The responsibility to free the
815 /// constructed CFG belongs to the caller.
816 static CFG* buildCFG(const Decl *D, Stmt *AST, ASTContext *C,
817 const BuildOptions &BO);
819 /// createBlock - Create a new block in the CFG. The CFG owns the block;
820 /// the caller should not directly free it.
821 CFGBlock *createBlock();
823 /// setEntry - Set the entry block of the CFG. This is typically used
824 /// only during CFG construction. Most CFG clients expect that the
825 /// entry block has no predecessors and contains no statements.
826 void setEntry(CFGBlock *B) { Entry = B; }
828 /// setIndirectGotoBlock - Set the block used for indirect goto jumps.
829 /// This is typically used only during CFG construction.
830 void setIndirectGotoBlock(CFGBlock *B) { IndirectGotoBlock = B; }
832 //===--------------------------------------------------------------------===//
834 //===--------------------------------------------------------------------===//
836 typedef BumpVector<CFGBlock*> CFGBlockListTy;
837 typedef CFGBlockListTy::iterator iterator;
838 typedef CFGBlockListTy::const_iterator const_iterator;
839 typedef std::reverse_iterator<iterator> reverse_iterator;
840 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
842 CFGBlock & front() { return *Blocks.front(); }
843 CFGBlock & back() { return *Blocks.back(); }
845 iterator begin() { return Blocks.begin(); }
846 iterator end() { return Blocks.end(); }
847 const_iterator begin() const { return Blocks.begin(); }
848 const_iterator end() const { return Blocks.end(); }
850 graph_iterator nodes_begin() { return graph_iterator(Blocks.begin()); }
851 graph_iterator nodes_end() { return graph_iterator(Blocks.end()); }
852 const_graph_iterator nodes_begin() const {
853 return const_graph_iterator(Blocks.begin());
855 const_graph_iterator nodes_end() const {
856 return const_graph_iterator(Blocks.end());
859 reverse_iterator rbegin() { return Blocks.rbegin(); }
860 reverse_iterator rend() { return Blocks.rend(); }
861 const_reverse_iterator rbegin() const { return Blocks.rbegin(); }
862 const_reverse_iterator rend() const { return Blocks.rend(); }
864 CFGBlock & getEntry() { return *Entry; }
865 const CFGBlock & getEntry() const { return *Entry; }
866 CFGBlock & getExit() { return *Exit; }
867 const CFGBlock & getExit() const { return *Exit; }
869 CFGBlock * getIndirectGotoBlock() { return IndirectGotoBlock; }
870 const CFGBlock * getIndirectGotoBlock() const { return IndirectGotoBlock; }
872 typedef std::vector<const CFGBlock*>::const_iterator try_block_iterator;
873 try_block_iterator try_blocks_begin() const {
874 return TryDispatchBlocks.begin();
876 try_block_iterator try_blocks_end() const {
877 return TryDispatchBlocks.end();
880 void addTryDispatchBlock(const CFGBlock *block) {
881 TryDispatchBlocks.push_back(block);
884 /// Records a synthetic DeclStmt and the DeclStmt it was constructed from.
886 /// The CFG uses synthetic DeclStmts when a single AST DeclStmt contains
888 void addSyntheticDeclStmt(const DeclStmt *Synthetic,
889 const DeclStmt *Source) {
890 assert(Synthetic->isSingleDecl() && "Can handle single declarations only");
891 assert(Synthetic != Source && "Don't include original DeclStmts in map");
892 assert(!SyntheticDeclStmts.count(Synthetic) && "Already in map");
893 SyntheticDeclStmts[Synthetic] = Source;
896 typedef llvm::DenseMap<const DeclStmt *, const DeclStmt *>::const_iterator
897 synthetic_stmt_iterator;
899 /// Iterates over synthetic DeclStmts in the CFG.
901 /// Each element is a (synthetic statement, source statement) pair.
903 /// \sa addSyntheticDeclStmt
904 synthetic_stmt_iterator synthetic_stmt_begin() const {
905 return SyntheticDeclStmts.begin();
908 /// \sa synthetic_stmt_begin
909 synthetic_stmt_iterator synthetic_stmt_end() const {
910 return SyntheticDeclStmts.end();
913 //===--------------------------------------------------------------------===//
914 // Member templates useful for various batch operations over CFGs.
915 //===--------------------------------------------------------------------===//
917 template <typename CALLBACK>
918 void VisitBlockStmts(CALLBACK& O) const {
919 for (const_iterator I=begin(), E=end(); I != E; ++I)
920 for (CFGBlock::const_iterator BI=(*I)->begin(), BE=(*I)->end();
922 if (Optional<CFGStmt> stmt = BI->getAs<CFGStmt>())
923 O(const_cast<Stmt*>(stmt->getStmt()));
927 //===--------------------------------------------------------------------===//
928 // CFG Introspection.
929 //===--------------------------------------------------------------------===//
931 /// getNumBlockIDs - Returns the total number of BlockIDs allocated (which
933 unsigned getNumBlockIDs() const { return NumBlockIDs; }
935 /// size - Return the total number of CFGBlocks within the CFG
936 /// This is simply a renaming of the getNumBlockIDs(). This is necessary
937 /// because the dominator implementation needs such an interface.
938 unsigned size() const { return NumBlockIDs; }
940 //===--------------------------------------------------------------------===//
941 // CFG Debugging: Pretty-Printing and Visualization.
942 //===--------------------------------------------------------------------===//
944 void viewCFG(const LangOptions &LO) const;
945 void print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const;
946 void dump(const LangOptions &LO, bool ShowColors) const;
948 //===--------------------------------------------------------------------===//
949 // Internal: constructors and data.
950 //===--------------------------------------------------------------------===//
953 : Entry(nullptr), Exit(nullptr), IndirectGotoBlock(nullptr), NumBlockIDs(0),
954 Blocks(BlkBVC, 10) {}
956 llvm::BumpPtrAllocator& getAllocator() {
957 return BlkBVC.getAllocator();
960 BumpVectorContext &getBumpVectorContext() {
967 CFGBlock* IndirectGotoBlock; // Special block to contain collective dispatch
968 // for indirect gotos
969 unsigned NumBlockIDs;
971 BumpVectorContext BlkBVC;
973 CFGBlockListTy Blocks;
975 /// C++ 'try' statements are modeled with an indirect dispatch block.
976 /// This is the collection of such blocks present in the CFG.
977 std::vector<const CFGBlock *> TryDispatchBlocks;
979 /// Collects DeclStmts synthesized for this CFG and maps each one back to its
981 llvm::DenseMap<const DeclStmt *, const DeclStmt *> SyntheticDeclStmts;
983 } // end namespace clang
985 //===----------------------------------------------------------------------===//
986 // GraphTraits specializations for CFG basic block graphs (source-level CFGs)
987 //===----------------------------------------------------------------------===//
991 /// Implement simplify_type for CFGTerminator, so that we can dyn_cast from
992 /// CFGTerminator to a specific Stmt class.
993 template <> struct simplify_type< ::clang::CFGTerminator> {
994 typedef ::clang::Stmt *SimpleType;
995 static SimpleType getSimplifiedValue(::clang::CFGTerminator Val) {
996 return Val.getStmt();
1000 // Traits for: CFGBlock
1002 template <> struct GraphTraits< ::clang::CFGBlock *> {
1003 typedef ::clang::CFGBlock NodeType;
1004 typedef ::clang::CFGBlock::succ_iterator ChildIteratorType;
1006 static NodeType* getEntryNode(::clang::CFGBlock *BB)
1009 static inline ChildIteratorType child_begin(NodeType* N)
1010 { return N->succ_begin(); }
1012 static inline ChildIteratorType child_end(NodeType* N)
1013 { return N->succ_end(); }
1016 template <> struct GraphTraits< const ::clang::CFGBlock *> {
1017 typedef const ::clang::CFGBlock NodeType;
1018 typedef ::clang::CFGBlock::const_succ_iterator ChildIteratorType;
1020 static NodeType* getEntryNode(const clang::CFGBlock *BB)
1023 static inline ChildIteratorType child_begin(NodeType* N)
1024 { return N->succ_begin(); }
1026 static inline ChildIteratorType child_end(NodeType* N)
1027 { return N->succ_end(); }
1030 template <> struct GraphTraits<Inverse< ::clang::CFGBlock*> > {
1031 typedef ::clang::CFGBlock NodeType;
1032 typedef ::clang::CFGBlock::const_pred_iterator ChildIteratorType;
1034 static NodeType *getEntryNode(Inverse< ::clang::CFGBlock*> G)
1037 static inline ChildIteratorType child_begin(NodeType* N)
1038 { return N->pred_begin(); }
1040 static inline ChildIteratorType child_end(NodeType* N)
1041 { return N->pred_end(); }
1044 template <> struct GraphTraits<Inverse<const ::clang::CFGBlock*> > {
1045 typedef const ::clang::CFGBlock NodeType;
1046 typedef ::clang::CFGBlock::const_pred_iterator ChildIteratorType;
1048 static NodeType *getEntryNode(Inverse<const ::clang::CFGBlock*> G)
1051 static inline ChildIteratorType child_begin(NodeType* N)
1052 { return N->pred_begin(); }
1054 static inline ChildIteratorType child_end(NodeType* N)
1055 { return N->pred_end(); }
1060 template <> struct GraphTraits< ::clang::CFG* >
1061 : public GraphTraits< ::clang::CFGBlock *> {
1063 typedef ::clang::CFG::graph_iterator nodes_iterator;
1065 static NodeType *getEntryNode(::clang::CFG* F) { return &F->getEntry(); }
1066 static nodes_iterator nodes_begin(::clang::CFG* F) { return F->nodes_begin();}
1067 static nodes_iterator nodes_end(::clang::CFG* F) { return F->nodes_end(); }
1068 static unsigned size(::clang::CFG* F) { return F->size(); }
1071 template <> struct GraphTraits<const ::clang::CFG* >
1072 : public GraphTraits<const ::clang::CFGBlock *> {
1074 typedef ::clang::CFG::const_graph_iterator nodes_iterator;
1076 static NodeType *getEntryNode( const ::clang::CFG* F) {
1077 return &F->getEntry();
1079 static nodes_iterator nodes_begin( const ::clang::CFG* F) {
1080 return F->nodes_begin();
1082 static nodes_iterator nodes_end( const ::clang::CFG* F) {
1083 return F->nodes_end();
1085 static unsigned size(const ::clang::CFG* F) {
1090 template <> struct GraphTraits<Inverse< ::clang::CFG*> >
1091 : public GraphTraits<Inverse< ::clang::CFGBlock*> > {
1093 typedef ::clang::CFG::graph_iterator nodes_iterator;
1095 static NodeType *getEntryNode( ::clang::CFG* F) { return &F->getExit(); }
1096 static nodes_iterator nodes_begin( ::clang::CFG* F) {return F->nodes_begin();}
1097 static nodes_iterator nodes_end( ::clang::CFG* F) { return F->nodes_end(); }
1100 template <> struct GraphTraits<Inverse<const ::clang::CFG*> >
1101 : public GraphTraits<Inverse<const ::clang::CFGBlock*> > {
1103 typedef ::clang::CFG::const_graph_iterator nodes_iterator;
1105 static NodeType *getEntryNode(const ::clang::CFG* F) { return &F->getExit(); }
1106 static nodes_iterator nodes_begin(const ::clang::CFG* F) {
1107 return F->nodes_begin();
1109 static nodes_iterator nodes_end(const ::clang::CFG* F) {
1110 return F->nodes_end();
1113 } // end llvm namespace