1 //===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the CFG and CFGBuilder classes for representing and
11 // building Control-Flow Graphs (CFGs) from ASTs.
13 //===----------------------------------------------------------------------===//
15 #include "clang/Analysis/CFG.h"
16 #include "clang/AST/ASTContext.h"
17 #include "clang/AST/Attr.h"
18 #include "clang/AST/CharUnits.h"
19 #include "clang/AST/DeclCXX.h"
20 #include "clang/AST/PrettyPrinter.h"
21 #include "clang/AST/StmtVisitor.h"
22 #include "llvm/ADT/DenseMap.h"
23 #include "llvm/ADT/OwningPtr.h"
24 #include "llvm/ADT/SmallPtrSet.h"
25 #include "llvm/Support/Allocator.h"
26 #include "llvm/Support/Format.h"
27 #include "llvm/Support/GraphWriter.h"
28 #include "llvm/Support/SaveAndRestore.h"
30 using namespace clang;
34 static SourceLocation GetEndLoc(Decl *D) {
35 if (VarDecl *VD = dyn_cast<VarDecl>(D))
36 if (Expr *Ex = VD->getInit())
37 return Ex->getSourceRange().getEnd();
38 return D->getLocation();
43 /// The CFG builder uses a recursive algorithm to build the CFG. When
44 /// we process an expression, sometimes we know that we must add the
45 /// subexpressions as block-level expressions. For example:
49 /// When processing the '||' expression, we know that exp1 and exp2
50 /// need to be added as block-level expressions, even though they
51 /// might not normally need to be. AddStmtChoice records this
52 /// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then
53 /// the builder has an option not to add a subexpression as a
54 /// block-level expression.
58 enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 };
60 AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {}
62 bool alwaysAdd(CFGBuilder &builder,
63 const Stmt *stmt) const;
65 /// Return a copy of this object, except with the 'always-add' bit
67 AddStmtChoice withAlwaysAdd(bool alwaysAdd) const {
68 return AddStmtChoice(alwaysAdd ? AlwaysAdd : NotAlwaysAdd);
75 /// LocalScope - Node in tree of local scopes created for C++ implicit
76 /// destructor calls generation. It contains list of automatic variables
77 /// declared in the scope and link to position in previous scope this scope
80 /// The process of creating local scopes is as follows:
81 /// - Init CFGBuilder::ScopePos with invalid position (equivalent for null),
82 /// - Before processing statements in scope (e.g. CompoundStmt) create
83 /// LocalScope object using CFGBuilder::ScopePos as link to previous scope
84 /// and set CFGBuilder::ScopePos to the end of new scope,
85 /// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points
87 /// - For every normal (without jump) end of scope add to CFGBlock destructors
88 /// for objects in the current scope,
89 /// - For every jump add to CFGBlock destructors for objects
90 /// between CFGBuilder::ScopePos and local scope position saved for jump
91 /// target. Thanks to C++ restrictions on goto jumps we can be sure that
92 /// jump target position will be on the path to root from CFGBuilder::ScopePos
93 /// (adding any variable that doesn't need constructor to be called to
94 /// LocalScope can break this assumption),
98 typedef BumpVector<VarDecl*> AutomaticVarsTy;
100 /// const_iterator - Iterates local scope backwards and jumps to previous
101 /// scope on reaching the beginning of currently iterated scope.
102 class const_iterator {
103 const LocalScope* Scope;
105 /// VarIter is guaranteed to be greater then 0 for every valid iterator.
106 /// Invalid iterator (with null Scope) has VarIter equal to 0.
110 /// Create invalid iterator. Dereferencing invalid iterator is not allowed.
111 /// Incrementing invalid iterator is allowed and will result in invalid
114 : Scope(NULL), VarIter(0) {}
116 /// Create valid iterator. In case when S.Prev is an invalid iterator and
117 /// I is equal to 0, this will create invalid iterator.
118 const_iterator(const LocalScope& S, unsigned I)
119 : Scope(&S), VarIter(I) {
120 // Iterator to "end" of scope is not allowed. Handle it by going up
121 // in scopes tree possibly up to invalid iterator in the root.
122 if (VarIter == 0 && Scope)
126 VarDecl *const* operator->() const {
127 assert (Scope && "Dereferencing invalid iterator is not allowed");
128 assert (VarIter != 0 && "Iterator has invalid value of VarIter member");
129 return &Scope->Vars[VarIter - 1];
131 VarDecl *operator*() const {
132 return *this->operator->();
135 const_iterator &operator++() {
139 assert (VarIter != 0 && "Iterator has invalid value of VarIter member");
145 const_iterator operator++(int) {
146 const_iterator P = *this;
151 bool operator==(const const_iterator &rhs) const {
152 return Scope == rhs.Scope && VarIter == rhs.VarIter;
154 bool operator!=(const const_iterator &rhs) const {
155 return !(*this == rhs);
158 operator bool() const {
159 return *this != const_iterator();
162 int distance(const_iterator L);
165 friend class const_iterator;
168 BumpVectorContext ctx;
170 /// Automatic variables in order of declaration.
171 AutomaticVarsTy Vars;
172 /// Iterator to variable in previous scope that was declared just before
173 /// begin of this scope.
177 /// Constructs empty scope linked to previous scope in specified place.
178 LocalScope(BumpVectorContext &ctx, const_iterator P)
179 : ctx(ctx), Vars(ctx, 4), Prev(P) {}
181 /// Begin of scope in direction of CFG building (backwards).
182 const_iterator begin() const { return const_iterator(*this, Vars.size()); }
184 void addVar(VarDecl *VD) {
185 Vars.push_back(VD, ctx);
189 /// distance - Calculates distance from this to L. L must be reachable from this
190 /// (with use of ++ operator). Cost of calculating the distance is linear w.r.t.
191 /// number of scopes between this and L.
192 int LocalScope::const_iterator::distance(LocalScope::const_iterator L) {
194 const_iterator F = *this;
195 while (F.Scope != L.Scope) {
196 assert (F != const_iterator()
197 && "L iterator is not reachable from F iterator.");
201 D += F.VarIter - L.VarIter;
205 /// BlockScopePosPair - Structure for specifying position in CFG during its
206 /// build process. It consists of CFGBlock that specifies position in CFG graph
207 /// and LocalScope::const_iterator that specifies position in LocalScope graph.
208 struct BlockScopePosPair {
209 BlockScopePosPair() : block(0) {}
210 BlockScopePosPair(CFGBlock *b, LocalScope::const_iterator scopePos)
211 : block(b), scopePosition(scopePos) {}
214 LocalScope::const_iterator scopePosition;
217 /// TryResult - a class representing a variant over the values
218 /// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool,
219 /// and is used by the CFGBuilder to decide if a branch condition
220 /// can be decided up front during CFG construction.
224 TryResult(bool b) : X(b ? 1 : 0) {}
225 TryResult() : X(-1) {}
227 bool isTrue() const { return X == 1; }
228 bool isFalse() const { return X == 0; }
229 bool isKnown() const { return X >= 0; }
236 class reverse_children {
237 llvm::SmallVector<Stmt *, 12> childrenBuf;
238 ArrayRef<Stmt*> children;
240 reverse_children(Stmt *S);
242 typedef ArrayRef<Stmt*>::reverse_iterator iterator;
243 iterator begin() const { return children.rbegin(); }
244 iterator end() const { return children.rend(); }
248 reverse_children::reverse_children(Stmt *S) {
249 if (CallExpr *CE = dyn_cast<CallExpr>(S)) {
250 children = CE->getRawSubExprs();
253 switch (S->getStmtClass()) {
254 // Note: Fill in this switch with more cases we want to optimize.
255 case Stmt::InitListExprClass: {
256 InitListExpr *IE = cast<InitListExpr>(S);
257 children = llvm::makeArrayRef(reinterpret_cast<Stmt**>(IE->getInits()),
265 // Default case for all other statements.
266 for (Stmt::child_range I = S->children(); I; ++I) {
267 childrenBuf.push_back(*I);
270 // This needs to be done *after* childrenBuf has been populated.
271 children = childrenBuf;
274 /// CFGBuilder - This class implements CFG construction from an AST.
275 /// The builder is stateful: an instance of the builder should be used to only
276 /// construct a single CFG.
280 /// CFGBuilder builder;
281 /// CFG* cfg = builder.BuildAST(stmt1);
283 /// CFG construction is done via a recursive walk of an AST. We actually parse
284 /// the AST in reverse order so that the successor of a basic block is
285 /// constructed prior to its predecessor. This allows us to nicely capture
286 /// implicit fall-throughs without extra basic blocks.
289 typedef BlockScopePosPair JumpTarget;
290 typedef BlockScopePosPair JumpSource;
297 JumpTarget ContinueJumpTarget;
298 JumpTarget BreakJumpTarget;
299 CFGBlock *SwitchTerminatedBlock;
300 CFGBlock *DefaultCaseBlock;
301 CFGBlock *TryTerminatedBlock;
303 // Current position in local scope.
304 LocalScope::const_iterator ScopePos;
306 // LabelMap records the mapping from Label expressions to their jump targets.
307 typedef llvm::DenseMap<LabelDecl*, JumpTarget> LabelMapTy;
310 // A list of blocks that end with a "goto" that must be backpatched to their
311 // resolved targets upon completion of CFG construction.
312 typedef std::vector<JumpSource> BackpatchBlocksTy;
313 BackpatchBlocksTy BackpatchBlocks;
315 // A list of labels whose address has been taken (for indirect gotos).
316 typedef llvm::SmallPtrSet<LabelDecl*, 5> LabelSetTy;
317 LabelSetTy AddressTakenLabels;
320 const CFG::BuildOptions &BuildOpts;
322 // State to track for building switch statements.
323 bool switchExclusivelyCovered;
324 Expr::EvalResult *switchCond;
326 CFG::BuildOptions::ForcedBlkExprs::value_type *cachedEntry;
327 const Stmt *lastLookup;
329 // Caches boolean evaluations of expressions to avoid multiple re-evaluations
330 // during construction of branches for chained logical operators.
331 typedef llvm::DenseMap<Expr *, TryResult> CachedBoolEvalsTy;
332 CachedBoolEvalsTy CachedBoolEvals;
335 explicit CFGBuilder(ASTContext *astContext,
336 const CFG::BuildOptions &buildOpts)
337 : Context(astContext), cfg(new CFG()), // crew a new CFG
338 Block(NULL), Succ(NULL),
339 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL),
340 TryTerminatedBlock(NULL), badCFG(false), BuildOpts(buildOpts),
341 switchExclusivelyCovered(false), switchCond(0),
342 cachedEntry(0), lastLookup(0) {}
344 // buildCFG - Used by external clients to construct the CFG.
345 CFG* buildCFG(const Decl *D, Stmt *Statement);
347 bool alwaysAdd(const Stmt *stmt);
350 // Visitors to walk an AST and construct the CFG.
351 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc);
352 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc);
353 CFGBlock *VisitBreakStmt(BreakStmt *B);
354 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc);
355 CFGBlock *VisitCaseStmt(CaseStmt *C);
356 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc);
357 CFGBlock *VisitCompoundStmt(CompoundStmt *C);
358 CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C,
360 CFGBlock *VisitContinueStmt(ContinueStmt *C);
361 CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
363 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S);
364 CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc);
365 CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S);
366 CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
368 CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
370 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T);
371 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S);
372 CFGBlock *VisitDeclStmt(DeclStmt *DS);
373 CFGBlock *VisitDeclSubExpr(DeclStmt *DS);
374 CFGBlock *VisitDefaultStmt(DefaultStmt *D);
375 CFGBlock *VisitDoStmt(DoStmt *D);
376 CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, AddStmtChoice asc);
377 CFGBlock *VisitForStmt(ForStmt *F);
378 CFGBlock *VisitGotoStmt(GotoStmt *G);
379 CFGBlock *VisitIfStmt(IfStmt *I);
380 CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc);
381 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I);
382 CFGBlock *VisitLabelStmt(LabelStmt *L);
383 CFGBlock *VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc);
384 CFGBlock *VisitLogicalOperator(BinaryOperator *B);
385 std::pair<CFGBlock *, CFGBlock *> VisitLogicalOperator(BinaryOperator *B,
388 CFGBlock *FalseBlock);
389 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc);
390 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S);
391 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S);
392 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S);
393 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S);
394 CFGBlock *VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S);
395 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S);
396 CFGBlock *VisitPseudoObjectExpr(PseudoObjectExpr *E);
397 CFGBlock *VisitReturnStmt(ReturnStmt *R);
398 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc);
399 CFGBlock *VisitSwitchStmt(SwitchStmt *S);
400 CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
402 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc);
403 CFGBlock *VisitWhileStmt(WhileStmt *W);
405 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd);
406 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc);
407 CFGBlock *VisitChildren(Stmt *S);
408 CFGBlock *VisitNoRecurse(Expr *E, AddStmtChoice asc);
410 // Visitors to walk an AST and generate destructors of temporaries in
412 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false);
413 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E);
414 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E);
415 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E,
416 bool BindToTemporary);
418 VisitConditionalOperatorForTemporaryDtors(AbstractConditionalOperator *E,
419 bool BindToTemporary);
421 // NYS == Not Yet Supported
427 void autoCreateBlock() { if (!Block) Block = createBlock(); }
428 CFGBlock *createBlock(bool add_successor = true);
429 CFGBlock *createNoReturnBlock();
431 CFGBlock *addStmt(Stmt *S) {
432 return Visit(S, AddStmtChoice::AlwaysAdd);
434 CFGBlock *addInitializer(CXXCtorInitializer *I);
435 void addAutomaticObjDtors(LocalScope::const_iterator B,
436 LocalScope::const_iterator E, Stmt *S);
437 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD);
439 // Local scopes creation.
440 LocalScope* createOrReuseLocalScope(LocalScope* Scope);
442 void addLocalScopeForStmt(Stmt *S);
443 LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS, LocalScope* Scope = NULL);
444 LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = NULL);
446 void addLocalScopeAndDtors(Stmt *S);
448 // Interface to CFGBlock - adding CFGElements.
449 void appendStmt(CFGBlock *B, const Stmt *S) {
450 if (alwaysAdd(S) && cachedEntry)
451 cachedEntry->second = B;
453 // All block-level expressions should have already been IgnoreParens()ed.
454 assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S);
455 B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext());
457 void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) {
458 B->appendInitializer(I, cfg->getBumpVectorContext());
460 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) {
461 B->appendBaseDtor(BS, cfg->getBumpVectorContext());
463 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) {
464 B->appendMemberDtor(FD, cfg->getBumpVectorContext());
466 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) {
467 B->appendTemporaryDtor(E, cfg->getBumpVectorContext());
469 void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) {
470 B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext());
473 void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
474 LocalScope::const_iterator B, LocalScope::const_iterator E);
476 void addSuccessor(CFGBlock *B, CFGBlock *S) {
477 B->addSuccessor(S, cfg->getBumpVectorContext());
480 /// Try and evaluate an expression to an integer constant.
481 bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) {
482 if (!BuildOpts.PruneTriviallyFalseEdges)
484 return !S->isTypeDependent() &&
485 !S->isValueDependent() &&
486 S->EvaluateAsRValue(outResult, *Context);
489 /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1
490 /// if we can evaluate to a known value, otherwise return -1.
491 TryResult tryEvaluateBool(Expr *S) {
492 if (!BuildOpts.PruneTriviallyFalseEdges ||
493 S->isTypeDependent() || S->isValueDependent())
496 if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(S)) {
497 if (Bop->isLogicalOp()) {
498 // Check the cache first.
499 CachedBoolEvalsTy::iterator I = CachedBoolEvals.find(S);
500 if (I != CachedBoolEvals.end())
501 return I->second; // already in map;
503 // Retrieve result at first, or the map might be updated.
504 TryResult Result = evaluateAsBooleanConditionNoCache(S);
505 CachedBoolEvals[S] = Result; // update or insert
509 switch (Bop->getOpcode()) {
511 // For 'x & 0' and 'x * 0', we can determine that
512 // the value is always false.
515 // If either operand is zero, we know the value
518 if (Bop->getLHS()->EvaluateAsInt(IntVal, *Context)) {
519 if (IntVal.getBoolValue() == false) {
520 return TryResult(false);
523 if (Bop->getRHS()->EvaluateAsInt(IntVal, *Context)) {
524 if (IntVal.getBoolValue() == false) {
525 return TryResult(false);
534 return evaluateAsBooleanConditionNoCache(S);
537 /// \brief Evaluate as boolean \param E without using the cache.
538 TryResult evaluateAsBooleanConditionNoCache(Expr *E) {
539 if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(E)) {
540 if (Bop->isLogicalOp()) {
541 TryResult LHS = tryEvaluateBool(Bop->getLHS());
543 // We were able to evaluate the LHS, see if we can get away with not
544 // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
545 if (LHS.isTrue() == (Bop->getOpcode() == BO_LOr))
548 TryResult RHS = tryEvaluateBool(Bop->getRHS());
550 if (Bop->getOpcode() == BO_LOr)
551 return LHS.isTrue() || RHS.isTrue();
553 return LHS.isTrue() && RHS.isTrue();
556 TryResult RHS = tryEvaluateBool(Bop->getRHS());
558 // We can't evaluate the LHS; however, sometimes the result
559 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
560 if (RHS.isTrue() == (Bop->getOpcode() == BO_LOr))
570 if (E->EvaluateAsBooleanCondition(Result, *Context))
578 inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder,
579 const Stmt *stmt) const {
580 return builder.alwaysAdd(stmt) || kind == AlwaysAdd;
583 bool CFGBuilder::alwaysAdd(const Stmt *stmt) {
584 bool shouldAdd = BuildOpts.alwaysAdd(stmt);
586 if (!BuildOpts.forcedBlkExprs)
589 if (lastLookup == stmt) {
591 assert(cachedEntry->first == stmt);
599 // Perform the lookup!
600 CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs;
603 // No need to update 'cachedEntry', since it will always be null.
604 assert(cachedEntry == 0);
608 CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt);
609 if (itr == fb->end()) {
618 // FIXME: Add support for dependent-sized array types in C++?
619 // Does it even make sense to build a CFG for an uninstantiated template?
620 static const VariableArrayType *FindVA(const Type *t) {
621 while (const ArrayType *vt = dyn_cast<ArrayType>(t)) {
622 if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt))
623 if (vat->getSizeExpr())
626 t = vt->getElementType().getTypePtr();
632 /// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an
633 /// arbitrary statement. Examples include a single expression or a function
634 /// body (compound statement). The ownership of the returned CFG is
635 /// transferred to the caller. If CFG construction fails, this method returns
637 CFG* CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) {
642 // Create an empty block that will serve as the exit block for the CFG. Since
643 // this is the first block added to the CFG, it will be implicitly registered
644 // as the exit block.
645 Succ = createBlock();
646 assert(Succ == &cfg->getExit());
647 Block = NULL; // the EXIT block is empty. Create all other blocks lazily.
649 if (BuildOpts.AddImplicitDtors)
650 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D))
651 addImplicitDtorsForDestructor(DD);
653 // Visit the statements and create the CFG.
654 CFGBlock *B = addStmt(Statement);
659 // For C++ constructor add initializers to CFG.
660 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) {
661 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(),
662 E = CD->init_rend(); I != E; ++I) {
663 B = addInitializer(*I);
672 // Backpatch the gotos whose label -> block mappings we didn't know when we
674 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(),
675 E = BackpatchBlocks.end(); I != E; ++I ) {
677 CFGBlock *B = I->block;
678 const GotoStmt *G = cast<GotoStmt>(B->getTerminator());
679 LabelMapTy::iterator LI = LabelMap.find(G->getLabel());
681 // If there is no target for the goto, then we are looking at an
682 // incomplete AST. Handle this by not registering a successor.
683 if (LI == LabelMap.end()) continue;
685 JumpTarget JT = LI->second;
686 prependAutomaticObjDtorsWithTerminator(B, I->scopePosition,
688 addSuccessor(B, JT.block);
691 // Add successors to the Indirect Goto Dispatch block (if we have one).
692 if (CFGBlock *B = cfg->getIndirectGotoBlock())
693 for (LabelSetTy::iterator I = AddressTakenLabels.begin(),
694 E = AddressTakenLabels.end(); I != E; ++I ) {
696 // Lookup the target block.
697 LabelMapTy::iterator LI = LabelMap.find(*I);
699 // If there is no target block that contains label, then we are looking
700 // at an incomplete AST. Handle this by not registering a successor.
701 if (LI == LabelMap.end()) continue;
703 addSuccessor(B, LI->second.block);
706 // Create an empty entry block that has no predecessors.
707 cfg->setEntry(createBlock());
712 /// createBlock - Used to lazily create blocks that are connected
713 /// to the current (global) succcessor.
714 CFGBlock *CFGBuilder::createBlock(bool add_successor) {
715 CFGBlock *B = cfg->createBlock();
716 if (add_successor && Succ)
717 addSuccessor(B, Succ);
721 /// createNoReturnBlock - Used to create a block is a 'noreturn' point in the
722 /// CFG. It is *not* connected to the current (global) successor, and instead
723 /// directly tied to the exit block in order to be reachable.
724 CFGBlock *CFGBuilder::createNoReturnBlock() {
725 CFGBlock *B = createBlock(false);
726 B->setHasNoReturnElement();
727 addSuccessor(B, &cfg->getExit());
731 /// addInitializer - Add C++ base or member initializer element to CFG.
732 CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) {
733 if (!BuildOpts.AddInitializers)
736 bool IsReference = false;
737 bool HasTemporaries = false;
739 // Destructors of temporaries in initialization expression should be called
740 // after initialization finishes.
741 Expr *Init = I->getInit();
743 if (FieldDecl *FD = I->getAnyMember())
744 IsReference = FD->getType()->isReferenceType();
745 HasTemporaries = isa<ExprWithCleanups>(Init);
747 if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
748 // Generate destructors for temporaries in initialization expression.
749 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
755 appendInitializer(Block, I);
758 if (HasTemporaries) {
759 // For expression with temporaries go directly to subexpression to omit
760 // generating destructors for the second time.
761 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr());
769 /// \brief Retrieve the type of the temporary object whose lifetime was
770 /// extended by a local reference with the given initializer.
771 static QualType getReferenceInitTemporaryType(ASTContext &Context,
775 Init = Init->IgnoreParens();
777 // Skip through cleanups.
778 if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Init)) {
779 Init = EWC->getSubExpr();
783 // Skip through the temporary-materialization expression.
784 if (const MaterializeTemporaryExpr *MTE
785 = dyn_cast<MaterializeTemporaryExpr>(Init)) {
786 Init = MTE->GetTemporaryExpr();
790 // Skip derived-to-base and no-op casts.
791 if (const CastExpr *CE = dyn_cast<CastExpr>(Init)) {
792 if ((CE->getCastKind() == CK_DerivedToBase ||
793 CE->getCastKind() == CK_UncheckedDerivedToBase ||
794 CE->getCastKind() == CK_NoOp) &&
795 Init->getType()->isRecordType()) {
796 Init = CE->getSubExpr();
801 // Skip member accesses into rvalues.
802 if (const MemberExpr *ME = dyn_cast<MemberExpr>(Init)) {
803 if (!ME->isArrow() && ME->getBase()->isRValue()) {
804 Init = ME->getBase();
812 return Init->getType();
815 /// addAutomaticObjDtors - Add to current block automatic objects destructors
816 /// for objects in range of local scope positions. Use S as trigger statement
818 void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B,
819 LocalScope::const_iterator E, Stmt *S) {
820 if (!BuildOpts.AddImplicitDtors)
826 // We need to append the destructors in reverse order, but any one of them
827 // may be a no-return destructor which changes the CFG. As a result, buffer
828 // this sequence up and replay them in reverse order when appending onto the
830 SmallVector<VarDecl*, 10> Decls;
831 Decls.reserve(B.distance(E));
832 for (LocalScope::const_iterator I = B; I != E; ++I)
835 for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(),
838 // If this destructor is marked as a no-return destructor, we need to
839 // create a new block for the destructor which does not have as a successor
840 // anything built thus far: control won't flow out of this block.
841 QualType Ty = (*I)->getType();
842 if (Ty->isReferenceType()) {
843 Ty = getReferenceInitTemporaryType(*Context, (*I)->getInit());
845 Ty = Context->getBaseElementType(Ty);
847 const CXXDestructorDecl *Dtor = Ty->getAsCXXRecordDecl()->getDestructor();
848 if (Dtor->isNoReturn())
849 Block = createNoReturnBlock();
853 appendAutomaticObjDtor(Block, *I, S);
857 /// addImplicitDtorsForDestructor - Add implicit destructors generated for
858 /// base and member objects in destructor.
859 void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) {
860 assert (BuildOpts.AddImplicitDtors
861 && "Can be called only when dtors should be added");
862 const CXXRecordDecl *RD = DD->getParent();
864 // At the end destroy virtual base objects.
865 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(),
866 VE = RD->vbases_end(); VI != VE; ++VI) {
867 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl();
868 if (!CD->hasTrivialDestructor()) {
870 appendBaseDtor(Block, VI);
874 // Before virtual bases destroy direct base objects.
875 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(),
876 BE = RD->bases_end(); BI != BE; ++BI) {
877 if (!BI->isVirtual()) {
878 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl();
879 if (!CD->hasTrivialDestructor()) {
881 appendBaseDtor(Block, BI);
886 // First destroy member objects.
887 for (CXXRecordDecl::field_iterator FI = RD->field_begin(),
888 FE = RD->field_end(); FI != FE; ++FI) {
889 // Check for constant size array. Set type to array element type.
890 QualType QT = FI->getType();
891 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
892 if (AT->getSize() == 0)
894 QT = AT->getElementType();
897 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
898 if (!CD->hasTrivialDestructor()) {
900 appendMemberDtor(Block, *FI);
905 /// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either
906 /// way return valid LocalScope object.
907 LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) {
909 llvm::BumpPtrAllocator &alloc = cfg->getAllocator();
910 Scope = alloc.Allocate<LocalScope>();
911 BumpVectorContext ctx(alloc);
912 new (Scope) LocalScope(ctx, ScopePos);
917 /// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement
918 /// that should create implicit scope (e.g. if/else substatements).
919 void CFGBuilder::addLocalScopeForStmt(Stmt *S) {
920 if (!BuildOpts.AddImplicitDtors)
923 LocalScope *Scope = 0;
925 // For compound statement we will be creating explicit scope.
926 if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
927 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end()
929 Stmt *SI = (*BI)->stripLabelLikeStatements();
930 if (DeclStmt *DS = dyn_cast<DeclStmt>(SI))
931 Scope = addLocalScopeForDeclStmt(DS, Scope);
936 // For any other statement scope will be implicit and as such will be
937 // interesting only for DeclStmt.
938 if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements()))
939 addLocalScopeForDeclStmt(DS);
942 /// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will
943 /// reuse Scope if not NULL.
944 LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS,
946 if (!BuildOpts.AddImplicitDtors)
949 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end()
951 if (VarDecl *VD = dyn_cast<VarDecl>(*DI))
952 Scope = addLocalScopeForVarDecl(VD, Scope);
957 /// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will
958 /// create add scope for automatic objects and temporary objects bound to
959 /// const reference. Will reuse Scope if not NULL.
960 LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD,
962 if (!BuildOpts.AddImplicitDtors)
965 // Check if variable is local.
966 switch (VD->getStorageClass()) {
971 default: return Scope;
974 // Check for const references bound to temporary. Set type to pointee.
975 QualType QT = VD->getType();
976 if (QT.getTypePtr()->isReferenceType()) {
977 if (!VD->extendsLifetimeOfTemporary())
980 QT = getReferenceInitTemporaryType(*Context, VD->getInit());
983 // Check for constant size array. Set type to array element type.
984 while (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
985 if (AT->getSize() == 0)
987 QT = AT->getElementType();
990 // Check if type is a C++ class with non-trivial destructor.
991 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
992 if (!CD->hasTrivialDestructor()) {
993 // Add the variable to scope
994 Scope = createOrReuseLocalScope(Scope);
996 ScopePos = Scope->begin();
1001 /// addLocalScopeAndDtors - For given statement add local scope for it and
1002 /// add destructors that will cleanup the scope. Will reuse Scope if not NULL.
1003 void CFGBuilder::addLocalScopeAndDtors(Stmt *S) {
1004 if (!BuildOpts.AddImplicitDtors)
1007 LocalScope::const_iterator scopeBeginPos = ScopePos;
1008 addLocalScopeForStmt(S);
1009 addAutomaticObjDtors(ScopePos, scopeBeginPos, S);
1012 /// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for
1013 /// variables with automatic storage duration to CFGBlock's elements vector.
1014 /// Elements will be prepended to physical beginning of the vector which
1015 /// happens to be logical end. Use blocks terminator as statement that specifies
1016 /// destructors call site.
1017 /// FIXME: This mechanism for adding automatic destructors doesn't handle
1018 /// no-return destructors properly.
1019 void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
1020 LocalScope::const_iterator B, LocalScope::const_iterator E) {
1021 BumpVectorContext &C = cfg->getBumpVectorContext();
1022 CFGBlock::iterator InsertPos
1023 = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C);
1024 for (LocalScope::const_iterator I = B; I != E; ++I)
1025 InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I,
1026 Blk->getTerminator());
1029 /// Visit - Walk the subtree of a statement and add extra
1030 /// blocks for ternary operators, &&, and ||. We also process "," and
1031 /// DeclStmts (which may contain nested control-flow).
1032 CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) {
1038 if (Expr *E = dyn_cast<Expr>(S))
1039 S = E->IgnoreParens();
1041 switch (S->getStmtClass()) {
1043 return VisitStmt(S, asc);
1045 case Stmt::AddrLabelExprClass:
1046 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc);
1048 case Stmt::BinaryConditionalOperatorClass:
1049 return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc);
1051 case Stmt::BinaryOperatorClass:
1052 return VisitBinaryOperator(cast<BinaryOperator>(S), asc);
1054 case Stmt::BlockExprClass:
1055 return VisitNoRecurse(cast<Expr>(S), asc);
1057 case Stmt::BreakStmtClass:
1058 return VisitBreakStmt(cast<BreakStmt>(S));
1060 case Stmt::CallExprClass:
1061 case Stmt::CXXOperatorCallExprClass:
1062 case Stmt::CXXMemberCallExprClass:
1063 case Stmt::UserDefinedLiteralClass:
1064 return VisitCallExpr(cast<CallExpr>(S), asc);
1066 case Stmt::CaseStmtClass:
1067 return VisitCaseStmt(cast<CaseStmt>(S));
1069 case Stmt::ChooseExprClass:
1070 return VisitChooseExpr(cast<ChooseExpr>(S), asc);
1072 case Stmt::CompoundStmtClass:
1073 return VisitCompoundStmt(cast<CompoundStmt>(S));
1075 case Stmt::ConditionalOperatorClass:
1076 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc);
1078 case Stmt::ContinueStmtClass:
1079 return VisitContinueStmt(cast<ContinueStmt>(S));
1081 case Stmt::CXXCatchStmtClass:
1082 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S));
1084 case Stmt::ExprWithCleanupsClass:
1085 return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc);
1087 case Stmt::CXXDefaultArgExprClass:
1088 // FIXME: The expression inside a CXXDefaultArgExpr is owned by the
1089 // called function's declaration, not by the caller. If we simply add
1090 // this expression to the CFG, we could end up with the same Expr
1091 // appearing multiple times.
1092 // PR13385 / <rdar://problem/12156507>
1093 return VisitStmt(S, asc);
1095 case Stmt::CXXBindTemporaryExprClass:
1096 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc);
1098 case Stmt::CXXConstructExprClass:
1099 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc);
1101 case Stmt::CXXFunctionalCastExprClass:
1102 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc);
1104 case Stmt::CXXTemporaryObjectExprClass:
1105 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc);
1107 case Stmt::CXXThrowExprClass:
1108 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S));
1110 case Stmt::CXXTryStmtClass:
1111 return VisitCXXTryStmt(cast<CXXTryStmt>(S));
1113 case Stmt::CXXForRangeStmtClass:
1114 return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S));
1116 case Stmt::DeclStmtClass:
1117 return VisitDeclStmt(cast<DeclStmt>(S));
1119 case Stmt::DefaultStmtClass:
1120 return VisitDefaultStmt(cast<DefaultStmt>(S));
1122 case Stmt::DoStmtClass:
1123 return VisitDoStmt(cast<DoStmt>(S));
1125 case Stmt::ForStmtClass:
1126 return VisitForStmt(cast<ForStmt>(S));
1128 case Stmt::GotoStmtClass:
1129 return VisitGotoStmt(cast<GotoStmt>(S));
1131 case Stmt::IfStmtClass:
1132 return VisitIfStmt(cast<IfStmt>(S));
1134 case Stmt::ImplicitCastExprClass:
1135 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc);
1137 case Stmt::IndirectGotoStmtClass:
1138 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S));
1140 case Stmt::LabelStmtClass:
1141 return VisitLabelStmt(cast<LabelStmt>(S));
1143 case Stmt::LambdaExprClass:
1144 return VisitLambdaExpr(cast<LambdaExpr>(S), asc);
1146 case Stmt::MemberExprClass:
1147 return VisitMemberExpr(cast<MemberExpr>(S), asc);
1149 case Stmt::NullStmtClass:
1152 case Stmt::ObjCAtCatchStmtClass:
1153 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S));
1155 case Stmt::ObjCAutoreleasePoolStmtClass:
1156 return VisitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(S));
1158 case Stmt::ObjCAtSynchronizedStmtClass:
1159 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S));
1161 case Stmt::ObjCAtThrowStmtClass:
1162 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S));
1164 case Stmt::ObjCAtTryStmtClass:
1165 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S));
1167 case Stmt::ObjCForCollectionStmtClass:
1168 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S));
1170 case Stmt::OpaqueValueExprClass:
1173 case Stmt::PseudoObjectExprClass:
1174 return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S));
1176 case Stmt::ReturnStmtClass:
1177 return VisitReturnStmt(cast<ReturnStmt>(S));
1179 case Stmt::UnaryExprOrTypeTraitExprClass:
1180 return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S),
1183 case Stmt::StmtExprClass:
1184 return VisitStmtExpr(cast<StmtExpr>(S), asc);
1186 case Stmt::SwitchStmtClass:
1187 return VisitSwitchStmt(cast<SwitchStmt>(S));
1189 case Stmt::UnaryOperatorClass:
1190 return VisitUnaryOperator(cast<UnaryOperator>(S), asc);
1192 case Stmt::WhileStmtClass:
1193 return VisitWhileStmt(cast<WhileStmt>(S));
1197 CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) {
1198 if (asc.alwaysAdd(*this, S)) {
1200 appendStmt(Block, S);
1203 return VisitChildren(S);
1206 /// VisitChildren - Visit the children of a Stmt.
1207 CFGBlock *CFGBuilder::VisitChildren(Stmt *S) {
1208 CFGBlock *B = Block;
1210 // Visit the children in their reverse order so that they appear in
1211 // left-to-right (natural) order in the CFG.
1212 reverse_children RChildren(S);
1213 for (reverse_children::iterator I = RChildren.begin(), E = RChildren.end();
1215 if (Stmt *Child = *I)
1216 if (CFGBlock *R = Visit(Child))
1222 CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A,
1223 AddStmtChoice asc) {
1224 AddressTakenLabels.insert(A->getLabel());
1226 if (asc.alwaysAdd(*this, A)) {
1228 appendStmt(Block, A);
1234 CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U,
1235 AddStmtChoice asc) {
1236 if (asc.alwaysAdd(*this, U)) {
1238 appendStmt(Block, U);
1241 return Visit(U->getSubExpr(), AddStmtChoice());
1244 CFGBlock *CFGBuilder::VisitLogicalOperator(BinaryOperator *B) {
1245 CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
1246 appendStmt(ConfluenceBlock, B);
1251 return VisitLogicalOperator(B, 0, ConfluenceBlock, ConfluenceBlock).first;
1254 std::pair<CFGBlock*, CFGBlock*>
1255 CFGBuilder::VisitLogicalOperator(BinaryOperator *B,
1257 CFGBlock *TrueBlock,
1258 CFGBlock *FalseBlock) {
1260 // Introspect the RHS. If it is a nested logical operation, we recursively
1261 // build the CFG using this function. Otherwise, resort to default
1262 // CFG construction behavior.
1263 Expr *RHS = B->getRHS()->IgnoreParens();
1264 CFGBlock *RHSBlock, *ExitBlock;
1267 if (BinaryOperator *B_RHS = dyn_cast<BinaryOperator>(RHS))
1268 if (B_RHS->isLogicalOp()) {
1269 llvm::tie(RHSBlock, ExitBlock) =
1270 VisitLogicalOperator(B_RHS, Term, TrueBlock, FalseBlock);
1274 // The RHS is not a nested logical operation. Don't push the terminator
1275 // down further, but instead visit RHS and construct the respective
1276 // pieces of the CFG, and link up the RHSBlock with the terminator
1277 // we have been provided.
1278 ExitBlock = RHSBlock = createBlock(false);
1281 assert(TrueBlock == FalseBlock);
1282 addSuccessor(RHSBlock, TrueBlock);
1285 RHSBlock->setTerminator(Term);
1286 TryResult KnownVal = tryEvaluateBool(RHS);
1287 addSuccessor(RHSBlock, KnownVal.isFalse() ? NULL : TrueBlock);
1288 addSuccessor(RHSBlock, KnownVal.isTrue() ? NULL : FalseBlock);
1292 RHSBlock = addStmt(RHS);
1297 return std::make_pair((CFGBlock*)0, (CFGBlock*)0);
1299 // Generate the blocks for evaluating the LHS.
1300 Expr *LHS = B->getLHS()->IgnoreParens();
1302 if (BinaryOperator *B_LHS = dyn_cast<BinaryOperator>(LHS))
1303 if (B_LHS->isLogicalOp()) {
1304 if (B->getOpcode() == BO_LOr)
1305 FalseBlock = RHSBlock;
1307 TrueBlock = RHSBlock;
1309 // For the LHS, treat 'B' as the terminator that we want to sink
1310 // into the nested branch. The RHS always gets the top-most
1312 return VisitLogicalOperator(B_LHS, B, TrueBlock, FalseBlock);
1315 // Create the block evaluating the LHS.
1316 // This contains the '&&' or '||' as the terminator.
1317 CFGBlock *LHSBlock = createBlock(false);
1318 LHSBlock->setTerminator(B);
1321 CFGBlock *EntryLHSBlock = addStmt(LHS);
1324 return std::make_pair((CFGBlock*)0, (CFGBlock*)0);
1326 // See if this is a known constant.
1327 TryResult KnownVal = tryEvaluateBool(LHS);
1329 // Now link the LHSBlock with RHSBlock.
1330 if (B->getOpcode() == BO_LOr) {
1331 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : TrueBlock);
1332 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : RHSBlock);
1334 assert(B->getOpcode() == BO_LAnd);
1335 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock);
1336 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : FalseBlock);
1339 return std::make_pair(EntryLHSBlock, ExitBlock);
1343 CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B,
1344 AddStmtChoice asc) {
1346 if (B->isLogicalOp())
1347 return VisitLogicalOperator(B);
1349 if (B->getOpcode() == BO_Comma) { // ,
1351 appendStmt(Block, B);
1352 addStmt(B->getRHS());
1353 return addStmt(B->getLHS());
1356 if (B->isAssignmentOp()) {
1357 if (asc.alwaysAdd(*this, B)) {
1359 appendStmt(Block, B);
1362 return Visit(B->getRHS());
1365 if (asc.alwaysAdd(*this, B)) {
1367 appendStmt(Block, B);
1370 CFGBlock *RBlock = Visit(B->getRHS());
1371 CFGBlock *LBlock = Visit(B->getLHS());
1372 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr
1373 // containing a DoStmt, and the LHS doesn't create a new block, then we should
1374 // return RBlock. Otherwise we'll incorrectly return NULL.
1375 return (LBlock ? LBlock : RBlock);
1378 CFGBlock *CFGBuilder::VisitNoRecurse(Expr *E, AddStmtChoice asc) {
1379 if (asc.alwaysAdd(*this, E)) {
1381 appendStmt(Block, E);
1386 CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) {
1387 // "break" is a control-flow statement. Thus we stop processing the current
1392 // Now create a new block that ends with the break statement.
1393 Block = createBlock(false);
1394 Block->setTerminator(B);
1396 // If there is no target for the break, then we are looking at an incomplete
1397 // AST. This means that the CFG cannot be constructed.
1398 if (BreakJumpTarget.block) {
1399 addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B);
1400 addSuccessor(Block, BreakJumpTarget.block);
1408 static bool CanThrow(Expr *E, ASTContext &Ctx) {
1409 QualType Ty = E->getType();
1410 if (Ty->isFunctionPointerType())
1411 Ty = Ty->getAs<PointerType>()->getPointeeType();
1412 else if (Ty->isBlockPointerType())
1413 Ty = Ty->getAs<BlockPointerType>()->getPointeeType();
1415 const FunctionType *FT = Ty->getAs<FunctionType>();
1417 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT))
1418 if (!isUnresolvedExceptionSpec(Proto->getExceptionSpecType()) &&
1419 Proto->isNothrow(Ctx))
1425 CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) {
1426 // Compute the callee type.
1427 QualType calleeType = C->getCallee()->getType();
1428 if (calleeType == Context->BoundMemberTy) {
1429 QualType boundType = Expr::findBoundMemberType(C->getCallee());
1431 // We should only get a null bound type if processing a dependent
1432 // CFG. Recover by assuming nothing.
1433 if (!boundType.isNull()) calleeType = boundType;
1436 // If this is a call to a no-return function, this stops the block here.
1437 bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn();
1439 bool AddEHEdge = false;
1441 // Languages without exceptions are assumed to not throw.
1442 if (Context->getLangOpts().Exceptions) {
1443 if (BuildOpts.AddEHEdges)
1447 if (FunctionDecl *FD = C->getDirectCallee()) {
1448 if (FD->isNoReturn())
1450 if (FD->hasAttr<NoThrowAttr>())
1454 if (!CanThrow(C->getCallee(), *Context))
1457 if (!NoReturn && !AddEHEdge)
1458 return VisitStmt(C, asc.withAlwaysAdd(true));
1467 Block = createNoReturnBlock();
1469 Block = createBlock();
1471 appendStmt(Block, C);
1474 // Add exceptional edges.
1475 if (TryTerminatedBlock)
1476 addSuccessor(Block, TryTerminatedBlock);
1478 addSuccessor(Block, &cfg->getExit());
1481 return VisitChildren(C);
1484 CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C,
1485 AddStmtChoice asc) {
1486 CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
1487 appendStmt(ConfluenceBlock, C);
1491 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
1492 Succ = ConfluenceBlock;
1494 CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd);
1498 Succ = ConfluenceBlock;
1500 CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd);
1504 Block = createBlock(false);
1505 // See if this is a known constant.
1506 const TryResult& KnownVal = tryEvaluateBool(C->getCond());
1507 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock);
1508 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock);
1509 Block->setTerminator(C);
1510 return addStmt(C->getCond());
1514 CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) {
1515 addLocalScopeAndDtors(C);
1516 CFGBlock *LastBlock = Block;
1518 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend();
1520 // If we hit a segment of code just containing ';' (NullStmts), we can
1521 // get a null block back. In such cases, just use the LastBlock
1522 if (CFGBlock *newBlock = addStmt(*I))
1523 LastBlock = newBlock;
1532 CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C,
1533 AddStmtChoice asc) {
1534 const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C);
1535 const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : NULL);
1537 // Create the confluence block that will "merge" the results of the ternary
1539 CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
1540 appendStmt(ConfluenceBlock, C);
1544 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
1546 // Create a block for the LHS expression if there is an LHS expression. A
1547 // GCC extension allows LHS to be NULL, causing the condition to be the
1548 // value that is returned instead.
1549 // e.g: x ?: y is shorthand for: x ? x : y;
1550 Succ = ConfluenceBlock;
1552 CFGBlock *LHSBlock = 0;
1553 const Expr *trueExpr = C->getTrueExpr();
1554 if (trueExpr != opaqueValue) {
1555 LHSBlock = Visit(C->getTrueExpr(), alwaysAdd);
1561 LHSBlock = ConfluenceBlock;
1563 // Create the block for the RHS expression.
1564 Succ = ConfluenceBlock;
1565 CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd);
1569 // If the condition is a logical '&&' or '||', build a more accurate CFG.
1570 if (BinaryOperator *Cond =
1571 dyn_cast<BinaryOperator>(C->getCond()->IgnoreParens()))
1572 if (Cond->isLogicalOp())
1573 return VisitLogicalOperator(Cond, C, LHSBlock, RHSBlock).first;
1575 // Create the block that will contain the condition.
1576 Block = createBlock(false);
1578 // See if this is a known constant.
1579 const TryResult& KnownVal = tryEvaluateBool(C->getCond());
1580 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock);
1581 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock);
1582 Block->setTerminator(C);
1583 Expr *condExpr = C->getCond();
1586 // Run the condition expression if it's not trivially expressed in
1587 // terms of the opaque value (or if there is no opaque value).
1588 if (condExpr != opaqueValue)
1591 // Before that, run the common subexpression if there was one.
1592 // At least one of this or the above will be run.
1593 return addStmt(BCO->getCommon());
1596 return addStmt(condExpr);
1599 CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) {
1600 // Check if the Decl is for an __label__. If so, elide it from the
1602 if (isa<LabelDecl>(*DS->decl_begin()))
1605 // This case also handles static_asserts.
1606 if (DS->isSingleDecl())
1607 return VisitDeclSubExpr(DS);
1611 // Build an individual DeclStmt for each decl.
1612 for (DeclStmt::reverse_decl_iterator I = DS->decl_rbegin(),
1613 E = DS->decl_rend();
1615 // Get the alignment of the new DeclStmt, padding out to >=8 bytes.
1616 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8
1617 ? 8 : llvm::AlignOf<DeclStmt>::Alignment;
1619 // Allocate the DeclStmt using the BumpPtrAllocator. It will get
1620 // automatically freed with the CFG.
1621 DeclGroupRef DG(*I);
1623 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A);
1624 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D));
1626 // Append the fake DeclStmt to block.
1627 B = VisitDeclSubExpr(DSNew);
1633 /// VisitDeclSubExpr - Utility method to add block-level expressions for
1634 /// DeclStmts and initializers in them.
1635 CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) {
1636 assert(DS->isSingleDecl() && "Can handle single declarations only.");
1637 Decl *D = DS->getSingleDecl();
1639 if (isa<StaticAssertDecl>(D)) {
1640 // static_asserts aren't added to the CFG because they do not impact
1641 // runtime semantics.
1645 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl());
1649 appendStmt(Block, DS);
1653 bool IsReference = false;
1654 bool HasTemporaries = false;
1656 // Guard static initializers under a branch.
1657 CFGBlock *blockAfterStaticInit = 0;
1659 if (BuildOpts.AddStaticInitBranches && VD->isStaticLocal()) {
1660 // For static variables, we need to create a branch to track
1661 // whether or not they are initialized.
1668 blockAfterStaticInit = Succ;
1671 // Destructors of temporaries in initialization expression should be called
1672 // after initialization finishes.
1673 Expr *Init = VD->getInit();
1675 IsReference = VD->getType()->isReferenceType();
1676 HasTemporaries = isa<ExprWithCleanups>(Init);
1678 if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
1679 // Generate destructors for temporaries in initialization expression.
1680 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
1686 appendStmt(Block, DS);
1688 // Keep track of the last non-null block, as 'Block' can be nulled out
1689 // if the initializer expression is something like a 'while' in a
1690 // statement-expression.
1691 CFGBlock *LastBlock = Block;
1694 if (HasTemporaries) {
1695 // For expression with temporaries go directly to subexpression to omit
1696 // generating destructors for the second time.
1697 ExprWithCleanups *EC = cast<ExprWithCleanups>(Init);
1698 if (CFGBlock *newBlock = Visit(EC->getSubExpr()))
1699 LastBlock = newBlock;
1702 if (CFGBlock *newBlock = Visit(Init))
1703 LastBlock = newBlock;
1707 // If the type of VD is a VLA, then we must process its size expressions.
1708 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr());
1709 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) {
1710 if (CFGBlock *newBlock = addStmt(VA->getSizeExpr()))
1711 LastBlock = newBlock;
1714 // Remove variable from local scope.
1715 if (ScopePos && VD == *ScopePos)
1718 CFGBlock *B = LastBlock;
1719 if (blockAfterStaticInit) {
1721 Block = createBlock(false);
1722 Block->setTerminator(DS);
1723 addSuccessor(Block, blockAfterStaticInit);
1724 addSuccessor(Block, B);
1731 CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) {
1732 // We may see an if statement in the middle of a basic block, or it may be the
1733 // first statement we are processing. In either case, we create a new basic
1734 // block. First, we create the blocks for the then...else statements, and
1735 // then we create the block containing the if statement. If we were in the
1736 // middle of a block, we stop processing that block. That block is then the
1737 // implicit successor for the "then" and "else" clauses.
1739 // Save local scope position because in case of condition variable ScopePos
1740 // won't be restored when traversing AST.
1741 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
1743 // Create local scope for possible condition variable.
1744 // Store scope position. Add implicit destructor.
1745 if (VarDecl *VD = I->getConditionVariable()) {
1746 LocalScope::const_iterator BeginScopePos = ScopePos;
1747 addLocalScopeForVarDecl(VD);
1748 addAutomaticObjDtors(ScopePos, BeginScopePos, I);
1751 // The block we were processing is now finished. Make it the successor
1759 // Process the false branch.
1760 CFGBlock *ElseBlock = Succ;
1762 if (Stmt *Else = I->getElse()) {
1763 SaveAndRestore<CFGBlock*> sv(Succ);
1765 // NULL out Block so that the recursive call to Visit will
1766 // create a new basic block.
1769 // If branch is not a compound statement create implicit scope
1770 // and add destructors.
1771 if (!isa<CompoundStmt>(Else))
1772 addLocalScopeAndDtors(Else);
1774 ElseBlock = addStmt(Else);
1776 if (!ElseBlock) // Can occur when the Else body has all NullStmts.
1777 ElseBlock = sv.get();
1784 // Process the true branch.
1785 CFGBlock *ThenBlock;
1787 Stmt *Then = I->getThen();
1789 SaveAndRestore<CFGBlock*> sv(Succ);
1792 // If branch is not a compound statement create implicit scope
1793 // and add destructors.
1794 if (!isa<CompoundStmt>(Then))
1795 addLocalScopeAndDtors(Then);
1797 ThenBlock = addStmt(Then);
1800 // We can reach here if the "then" body has all NullStmts.
1801 // Create an empty block so we can distinguish between true and false
1802 // branches in path-sensitive analyses.
1803 ThenBlock = createBlock(false);
1804 addSuccessor(ThenBlock, sv.get());
1811 // Specially handle "if (expr1 || ...)" and "if (expr1 && ...)" by
1812 // having these handle the actual control-flow jump. Note that
1813 // if we introduce a condition variable, e.g. "if (int x = exp1 || exp2)"
1814 // we resort to the old control-flow behavior. This special handling
1815 // removes infeasible paths from the control-flow graph by having the
1816 // control-flow transfer of '&&' or '||' go directly into the then/else
1818 if (!I->getConditionVariable())
1819 if (BinaryOperator *Cond =
1820 dyn_cast<BinaryOperator>(I->getCond()->IgnoreParens()))
1821 if (Cond->isLogicalOp())
1822 return VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first;
1824 // Now create a new block containing the if statement.
1825 Block = createBlock(false);
1827 // Set the terminator of the new block to the If statement.
1828 Block->setTerminator(I);
1830 // See if this is a known constant.
1831 const TryResult &KnownVal = tryEvaluateBool(I->getCond());
1833 // Now add the successors.
1834 addSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock);
1835 addSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock);
1837 // Add the condition as the last statement in the new block. This may create
1838 // new blocks as the condition may contain control-flow. Any newly created
1839 // blocks will be pointed to be "Block".
1840 CFGBlock *LastBlock = addStmt(I->getCond());
1842 // Finally, if the IfStmt contains a condition variable, add both the IfStmt
1843 // and the condition variable initialization to the CFG.
1844 if (VarDecl *VD = I->getConditionVariable()) {
1845 if (Expr *Init = VD->getInit()) {
1847 appendStmt(Block, I->getConditionVariableDeclStmt());
1848 LastBlock = addStmt(Init);
1856 CFGBlock *CFGBuilder::VisitReturnStmt(ReturnStmt *R) {
1857 // If we were in the middle of a block we stop processing that block.
1859 // NOTE: If a "return" appears in the middle of a block, this means that the
1860 // code afterwards is DEAD (unreachable). We still keep a basic block
1861 // for that code; a simple "mark-and-sweep" from the entry block will be
1862 // able to report such dead blocks.
1864 // Create the new block.
1865 Block = createBlock(false);
1867 // The Exit block is the only successor.
1868 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R);
1869 addSuccessor(Block, &cfg->getExit());
1871 // Add the return statement to the block. This may create new blocks if R
1872 // contains control-flow (short-circuit operations).
1873 return VisitStmt(R, AddStmtChoice::AlwaysAdd);
1876 CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) {
1877 // Get the block of the labeled statement. Add it to our map.
1878 addStmt(L->getSubStmt());
1879 CFGBlock *LabelBlock = Block;
1881 if (!LabelBlock) // This can happen when the body is empty, i.e.
1882 LabelBlock = createBlock(); // scopes that only contains NullStmts.
1884 assert(LabelMap.find(L->getDecl()) == LabelMap.end() &&
1885 "label already in map");
1886 LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos);
1888 // Labels partition blocks, so this is the end of the basic block we were
1889 // processing (L is the block's label). Because this is label (and we have
1890 // already processed the substatement) there is no extra control-flow to worry
1892 LabelBlock->setLabel(L);
1896 // We set Block to NULL to allow lazy creation of a new block (if necessary);
1899 // This block is now the implicit successor of other blocks.
1905 CFGBlock *CFGBuilder::VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc) {
1906 CFGBlock *LastBlock = VisitNoRecurse(E, asc);
1907 for (LambdaExpr::capture_init_iterator it = E->capture_init_begin(),
1908 et = E->capture_init_end(); it != et; ++it) {
1909 if (Expr *Init = *it) {
1910 CFGBlock *Tmp = Visit(Init);
1918 CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) {
1919 // Goto is a control-flow statement. Thus we stop processing the current
1920 // block and create a new one.
1922 Block = createBlock(false);
1923 Block->setTerminator(G);
1925 // If we already know the mapping to the label block add the successor now.
1926 LabelMapTy::iterator I = LabelMap.find(G->getLabel());
1928 if (I == LabelMap.end())
1929 // We will need to backpatch this block later.
1930 BackpatchBlocks.push_back(JumpSource(Block, ScopePos));
1932 JumpTarget JT = I->second;
1933 addAutomaticObjDtors(ScopePos, JT.scopePosition, G);
1934 addSuccessor(Block, JT.block);
1940 CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) {
1941 CFGBlock *LoopSuccessor = NULL;
1943 // Save local scope position because in case of condition variable ScopePos
1944 // won't be restored when traversing AST.
1945 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
1947 // Create local scope for init statement and possible condition variable.
1948 // Add destructor for init statement and condition variable.
1949 // Store scope position for continue statement.
1950 if (Stmt *Init = F->getInit())
1951 addLocalScopeForStmt(Init);
1952 LocalScope::const_iterator LoopBeginScopePos = ScopePos;
1954 if (VarDecl *VD = F->getConditionVariable())
1955 addLocalScopeForVarDecl(VD);
1956 LocalScope::const_iterator ContinueScopePos = ScopePos;
1958 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F);
1960 // "for" is a control-flow statement. Thus we stop processing the current
1965 LoopSuccessor = Block;
1967 LoopSuccessor = Succ;
1969 // Save the current value for the break targets.
1970 // All breaks should go to the code following the loop.
1971 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
1972 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
1974 CFGBlock *BodyBlock = 0, *TransitionBlock = 0;
1976 // Now create the loop body.
1978 assert(F->getBody());
1980 // Save the current values for Block, Succ, continue and break targets.
1981 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
1982 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
1984 // Create an empty block to represent the transition block for looping back
1985 // to the head of the loop. If we have increment code, it will
1986 // go in this block as well.
1987 Block = Succ = TransitionBlock = createBlock(false);
1988 TransitionBlock->setLoopTarget(F);
1990 if (Stmt *I = F->getInc()) {
1991 // Generate increment code in its own basic block. This is the target of
1992 // continue statements.
1996 // Finish up the increment (or empty) block if it hasn't been already.
1998 assert(Block == Succ);
2004 // The starting block for the loop increment is the block that should
2005 // represent the 'loop target' for looping back to the start of the loop.
2006 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
2007 ContinueJumpTarget.block->setLoopTarget(F);
2009 // Loop body should end with destructor of Condition variable (if any).
2010 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F);
2012 // If body is not a compound statement create implicit scope
2013 // and add destructors.
2014 if (!isa<CompoundStmt>(F->getBody()))
2015 addLocalScopeAndDtors(F->getBody());
2017 // Now populate the body block, and in the process create new blocks as we
2018 // walk the body of the loop.
2019 BodyBlock = addStmt(F->getBody());
2022 // In the case of "for (...;...;...);" we can have a null BodyBlock.
2023 // Use the continue jump target as the proxy for the body.
2024 BodyBlock = ContinueJumpTarget.block;
2030 // Because of short-circuit evaluation, the condition of the loop can span
2031 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
2032 // evaluate the condition.
2033 CFGBlock *EntryConditionBlock = 0, *ExitConditionBlock = 0;
2036 Expr *C = F->getCond();
2038 // Specially handle logical operators, which have a slightly
2039 // more optimal CFG representation.
2040 if (BinaryOperator *Cond =
2041 dyn_cast_or_null<BinaryOperator>(C ? C->IgnoreParens() : 0))
2042 if (Cond->isLogicalOp()) {
2043 llvm::tie(EntryConditionBlock, ExitConditionBlock) =
2044 VisitLogicalOperator(Cond, F, BodyBlock, LoopSuccessor);
2048 // The default case when not handling logical operators.
2049 EntryConditionBlock = ExitConditionBlock = createBlock(false);
2050 ExitConditionBlock->setTerminator(F);
2052 // See if this is a known constant.
2053 TryResult KnownVal(true);
2056 // Now add the actual condition to the condition block.
2057 // Because the condition itself may contain control-flow, new blocks may
2058 // be created. Thus we update "Succ" after adding the condition.
2059 Block = ExitConditionBlock;
2060 EntryConditionBlock = addStmt(C);
2062 // If this block contains a condition variable, add both the condition
2063 // variable and initializer to the CFG.
2064 if (VarDecl *VD = F->getConditionVariable()) {
2065 if (Expr *Init = VD->getInit()) {
2067 appendStmt(Block, F->getConditionVariableDeclStmt());
2068 EntryConditionBlock = addStmt(Init);
2069 assert(Block == EntryConditionBlock);
2073 if (Block && badCFG)
2076 KnownVal = tryEvaluateBool(C);
2079 // Add the loop body entry as a successor to the condition.
2080 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock);
2081 // Link up the condition block with the code that follows the loop. (the
2083 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor);
2087 // Link up the loop-back block to the entry condition block.
2088 addSuccessor(TransitionBlock, EntryConditionBlock);
2090 // The condition block is the implicit successor for any code above the loop.
2091 Succ = EntryConditionBlock;
2093 // If the loop contains initialization, create a new block for those
2094 // statements. This block can also contain statements that precede the loop.
2095 if (Stmt *I = F->getInit()) {
2096 Block = createBlock();
2100 // There is no loop initialization. We are thus basically a while loop.
2101 // NULL out Block to force lazy block construction.
2103 Succ = EntryConditionBlock;
2104 return EntryConditionBlock;
2107 CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) {
2108 if (asc.alwaysAdd(*this, M)) {
2110 appendStmt(Block, M);
2112 return Visit(M->getBase());
2115 CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) {
2116 // Objective-C fast enumeration 'for' statements:
2117 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC
2119 // for ( Type newVariable in collection_expression ) { statements }
2124 // 1. collection_expression
2125 // T. jump to loop_entry
2127 // 1. side-effects of element expression
2128 // 1. ObjCForCollectionStmt [performs binding to newVariable]
2129 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil]
2132 // T. jump to loop_entry
2138 // Type existingItem;
2139 // for ( existingItem in expression ) { statements }
2143 // the same with newVariable replaced with existingItem; the binding works
2144 // the same except that for one ObjCForCollectionStmt::getElement() returns
2145 // a DeclStmt and the other returns a DeclRefExpr.
2148 CFGBlock *LoopSuccessor = 0;
2153 LoopSuccessor = Block;
2156 LoopSuccessor = Succ;
2158 // Build the condition blocks.
2159 CFGBlock *ExitConditionBlock = createBlock(false);
2161 // Set the terminator for the "exit" condition block.
2162 ExitConditionBlock->setTerminator(S);
2164 // The last statement in the block should be the ObjCForCollectionStmt, which
2165 // performs the actual binding to 'element' and determines if there are any
2166 // more items in the collection.
2167 appendStmt(ExitConditionBlock, S);
2168 Block = ExitConditionBlock;
2170 // Walk the 'element' expression to see if there are any side-effects. We
2171 // generate new blocks as necessary. We DON'T add the statement by default to
2172 // the CFG unless it contains control-flow.
2173 CFGBlock *EntryConditionBlock = Visit(S->getElement(),
2174 AddStmtChoice::NotAlwaysAdd);
2181 // The condition block is the implicit successor for the loop body as well as
2182 // any code above the loop.
2183 Succ = EntryConditionBlock;
2185 // Now create the true branch.
2187 // Save the current values for Succ, continue and break targets.
2188 SaveAndRestore<CFGBlock*> save_Succ(Succ);
2189 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
2190 save_break(BreakJumpTarget);
2192 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
2193 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos);
2195 CFGBlock *BodyBlock = addStmt(S->getBody());
2198 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;"
2204 // This new body block is a successor to our "exit" condition block.
2205 addSuccessor(ExitConditionBlock, BodyBlock);
2208 // Link up the condition block with the code that follows the loop.
2209 // (the false branch).
2210 addSuccessor(ExitConditionBlock, LoopSuccessor);
2212 // Now create a prologue block to contain the collection expression.
2213 Block = createBlock();
2214 return addStmt(S->getCollection());
2217 CFGBlock *CFGBuilder::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) {
2219 return addStmt(S->getSubStmt());
2220 // TODO: consider adding cleanups for the end of @autoreleasepool scope.
2223 CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) {
2224 // FIXME: Add locking 'primitives' to CFG for @synchronized.
2227 CFGBlock *SyncBlock = addStmt(S->getSynchBody());
2229 // The sync body starts its own basic block. This makes it a little easier
2230 // for diagnostic clients.
2239 // Add the @synchronized to the CFG.
2241 appendStmt(Block, S);
2243 // Inline the sync expression.
2244 return addStmt(S->getSynchExpr());
2247 CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) {
2252 CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) {
2255 // Add the PseudoObject as the last thing.
2256 appendStmt(Block, E);
2258 CFGBlock *lastBlock = Block;
2260 // Before that, evaluate all of the semantics in order. In
2261 // CFG-land, that means appending them in reverse order.
2262 for (unsigned i = E->getNumSemanticExprs(); i != 0; ) {
2263 Expr *Semantic = E->getSemanticExpr(--i);
2265 // If the semantic is an opaque value, we're being asked to bind
2266 // it to its source expression.
2267 if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
2268 Semantic = OVE->getSourceExpr();
2270 if (CFGBlock *B = Visit(Semantic))
2277 CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) {
2278 CFGBlock *LoopSuccessor = NULL;
2280 // Save local scope position because in case of condition variable ScopePos
2281 // won't be restored when traversing AST.
2282 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2284 // Create local scope for possible condition variable.
2285 // Store scope position for continue statement.
2286 LocalScope::const_iterator LoopBeginScopePos = ScopePos;
2287 if (VarDecl *VD = W->getConditionVariable()) {
2288 addLocalScopeForVarDecl(VD);
2289 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W);
2292 // "while" is a control-flow statement. Thus we stop processing the current
2297 LoopSuccessor = Block;
2300 LoopSuccessor = Succ;
2303 CFGBlock *BodyBlock = 0, *TransitionBlock = 0;
2305 // Process the loop body.
2307 assert(W->getBody());
2309 // Save the current values for Block, Succ, continue and break targets.
2310 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
2311 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
2312 save_break(BreakJumpTarget);
2314 // Create an empty block to represent the transition block for looping back
2315 // to the head of the loop.
2316 Succ = TransitionBlock = createBlock(false);
2317 TransitionBlock->setLoopTarget(W);
2318 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos);
2320 // All breaks should go to the code following the loop.
2321 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
2323 // Loop body should end with destructor of Condition variable (if any).
2324 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W);
2326 // If body is not a compound statement create implicit scope
2327 // and add destructors.
2328 if (!isa<CompoundStmt>(W->getBody()))
2329 addLocalScopeAndDtors(W->getBody());
2331 // Create the body. The returned block is the entry to the loop body.
2332 BodyBlock = addStmt(W->getBody());
2335 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;"
2336 else if (Block && badCFG)
2340 // Because of short-circuit evaluation, the condition of the loop can span
2341 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
2342 // evaluate the condition.
2343 CFGBlock *EntryConditionBlock = 0, *ExitConditionBlock = 0;
2346 Expr *C = W->getCond();
2348 // Specially handle logical operators, which have a slightly
2349 // more optimal CFG representation.
2350 if (BinaryOperator *Cond = dyn_cast<BinaryOperator>(C->IgnoreParens()))
2351 if (Cond->isLogicalOp()) {
2352 llvm::tie(EntryConditionBlock, ExitConditionBlock) =
2353 VisitLogicalOperator(Cond, W, BodyBlock,
2358 // The default case when not handling logical operators.
2359 ExitConditionBlock = createBlock(false);
2360 ExitConditionBlock->setTerminator(W);
2362 // Now add the actual condition to the condition block.
2363 // Because the condition itself may contain control-flow, new blocks may
2364 // be created. Thus we update "Succ" after adding the condition.
2365 Block = ExitConditionBlock;
2366 Block = EntryConditionBlock = addStmt(C);
2368 // If this block contains a condition variable, add both the condition
2369 // variable and initializer to the CFG.
2370 if (VarDecl *VD = W->getConditionVariable()) {
2371 if (Expr *Init = VD->getInit()) {
2373 appendStmt(Block, W->getConditionVariableDeclStmt());
2374 EntryConditionBlock = addStmt(Init);
2375 assert(Block == EntryConditionBlock);
2379 if (Block && badCFG)
2382 // See if this is a known constant.
2383 const TryResult& KnownVal = tryEvaluateBool(C);
2385 // Add the loop body entry as a successor to the condition.
2386 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock);
2387 // Link up the condition block with the code that follows the loop. (the
2389 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor);
2393 // Link up the loop-back block to the entry condition block.
2394 addSuccessor(TransitionBlock, EntryConditionBlock);
2396 // There can be no more statements in the condition block since we loop back
2397 // to this block. NULL out Block to force lazy creation of another block.
2400 // Return the condition block, which is the dominating block for the loop.
2401 Succ = EntryConditionBlock;
2402 return EntryConditionBlock;
2406 CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) {
2407 // FIXME: For now we pretend that @catch and the code it contains does not
2412 CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) {
2413 // FIXME: This isn't complete. We basically treat @throw like a return
2416 // If we were in the middle of a block we stop processing that block.
2420 // Create the new block.
2421 Block = createBlock(false);
2423 // The Exit block is the only successor.
2424 addSuccessor(Block, &cfg->getExit());
2426 // Add the statement to the block. This may create new blocks if S contains
2427 // control-flow (short-circuit operations).
2428 return VisitStmt(S, AddStmtChoice::AlwaysAdd);
2431 CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) {
2432 // If we were in the middle of a block we stop processing that block.
2436 // Create the new block.
2437 Block = createBlock(false);
2439 if (TryTerminatedBlock)
2440 // The current try statement is the only successor.
2441 addSuccessor(Block, TryTerminatedBlock);
2443 // otherwise the Exit block is the only successor.
2444 addSuccessor(Block, &cfg->getExit());
2446 // Add the statement to the block. This may create new blocks if S contains
2447 // control-flow (short-circuit operations).
2448 return VisitStmt(T, AddStmtChoice::AlwaysAdd);
2451 CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) {
2452 CFGBlock *LoopSuccessor = NULL;
2454 // "do...while" is a control-flow statement. Thus we stop processing the
2459 LoopSuccessor = Block;
2461 LoopSuccessor = Succ;
2463 // Because of short-circuit evaluation, the condition of the loop can span
2464 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
2465 // evaluate the condition.
2466 CFGBlock *ExitConditionBlock = createBlock(false);
2467 CFGBlock *EntryConditionBlock = ExitConditionBlock;
2469 // Set the terminator for the "exit" condition block.
2470 ExitConditionBlock->setTerminator(D);
2472 // Now add the actual condition to the condition block. Because the condition
2473 // itself may contain control-flow, new blocks may be created.
2474 if (Stmt *C = D->getCond()) {
2475 Block = ExitConditionBlock;
2476 EntryConditionBlock = addStmt(C);
2483 // The condition block is the implicit successor for the loop body.
2484 Succ = EntryConditionBlock;
2486 // See if this is a known constant.
2487 const TryResult &KnownVal = tryEvaluateBool(D->getCond());
2489 // Process the loop body.
2490 CFGBlock *BodyBlock = NULL;
2492 assert(D->getBody());
2494 // Save the current values for Block, Succ, and continue and break targets
2495 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
2496 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
2497 save_break(BreakJumpTarget);
2499 // All continues within this loop should go to the condition block
2500 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos);
2502 // All breaks should go to the code following the loop.
2503 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
2505 // NULL out Block to force lazy instantiation of blocks for the body.
2508 // If body is not a compound statement create implicit scope
2509 // and add destructors.
2510 if (!isa<CompoundStmt>(D->getBody()))
2511 addLocalScopeAndDtors(D->getBody());
2513 // Create the body. The returned block is the entry to the loop body.
2514 BodyBlock = addStmt(D->getBody());
2517 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)"
2523 if (!KnownVal.isFalse()) {
2524 // Add an intermediate block between the BodyBlock and the
2525 // ExitConditionBlock to represent the "loop back" transition. Create an
2526 // empty block to represent the transition block for looping back to the
2527 // head of the loop.
2528 // FIXME: Can we do this more efficiently without adding another block?
2531 CFGBlock *LoopBackBlock = createBlock();
2532 LoopBackBlock->setLoopTarget(D);
2534 // Add the loop body entry as a successor to the condition.
2535 addSuccessor(ExitConditionBlock, LoopBackBlock);
2538 addSuccessor(ExitConditionBlock, NULL);
2541 // Link up the condition block with the code that follows the loop.
2542 // (the false branch).
2543 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor);
2545 // There can be no more statements in the body block(s) since we loop back to
2546 // the body. NULL out Block to force lazy creation of another block.
2549 // Return the loop body, which is the dominating block for the loop.
2554 CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) {
2555 // "continue" is a control-flow statement. Thus we stop processing the
2560 // Now create a new block that ends with the continue statement.
2561 Block = createBlock(false);
2562 Block->setTerminator(C);
2564 // If there is no target for the continue, then we are looking at an
2565 // incomplete AST. This means the CFG cannot be constructed.
2566 if (ContinueJumpTarget.block) {
2567 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C);
2568 addSuccessor(Block, ContinueJumpTarget.block);
2575 CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
2576 AddStmtChoice asc) {
2578 if (asc.alwaysAdd(*this, E)) {
2580 appendStmt(Block, E);
2583 // VLA types have expressions that must be evaluated.
2584 CFGBlock *lastBlock = Block;
2586 if (E->isArgumentType()) {
2587 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr());
2588 VA != 0; VA = FindVA(VA->getElementType().getTypePtr()))
2589 lastBlock = addStmt(VA->getSizeExpr());
2594 /// VisitStmtExpr - Utility method to handle (nested) statement
2595 /// expressions (a GCC extension).
2596 CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) {
2597 if (asc.alwaysAdd(*this, SE)) {
2599 appendStmt(Block, SE);
2601 return VisitCompoundStmt(SE->getSubStmt());
2604 CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) {
2605 // "switch" is a control-flow statement. Thus we stop processing the current
2607 CFGBlock *SwitchSuccessor = NULL;
2609 // Save local scope position because in case of condition variable ScopePos
2610 // won't be restored when traversing AST.
2611 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2613 // Create local scope for possible condition variable.
2614 // Store scope position. Add implicit destructor.
2615 if (VarDecl *VD = Terminator->getConditionVariable()) {
2616 LocalScope::const_iterator SwitchBeginScopePos = ScopePos;
2617 addLocalScopeForVarDecl(VD);
2618 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator);
2624 SwitchSuccessor = Block;
2625 } else SwitchSuccessor = Succ;
2627 // Save the current "switch" context.
2628 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock),
2629 save_default(DefaultCaseBlock);
2630 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
2632 // Set the "default" case to be the block after the switch statement. If the
2633 // switch statement contains a "default:", this value will be overwritten with
2634 // the block for that code.
2635 DefaultCaseBlock = SwitchSuccessor;
2637 // Create a new block that will contain the switch statement.
2638 SwitchTerminatedBlock = createBlock(false);
2640 // Now process the switch body. The code after the switch is the implicit
2642 Succ = SwitchSuccessor;
2643 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos);
2645 // When visiting the body, the case statements should automatically get linked
2646 // up to the switch. We also don't keep a pointer to the body, since all
2647 // control-flow from the switch goes to case/default statements.
2648 assert(Terminator->getBody() && "switch must contain a non-NULL body");
2651 // For pruning unreachable case statements, save the current state
2652 // for tracking the condition value.
2653 SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered,
2656 // Determine if the switch condition can be explicitly evaluated.
2657 assert(Terminator->getCond() && "switch condition must be non-NULL");
2658 Expr::EvalResult result;
2659 bool b = tryEvaluate(Terminator->getCond(), result);
2660 SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond,
2663 // If body is not a compound statement create implicit scope
2664 // and add destructors.
2665 if (!isa<CompoundStmt>(Terminator->getBody()))
2666 addLocalScopeAndDtors(Terminator->getBody());
2668 addStmt(Terminator->getBody());
2674 // If we have no "default:" case, the default transition is to the code
2675 // following the switch body. Moreover, take into account if all the
2676 // cases of a switch are covered (e.g., switching on an enum value).
2677 addSuccessor(SwitchTerminatedBlock,
2678 switchExclusivelyCovered || Terminator->isAllEnumCasesCovered()
2679 ? 0 : DefaultCaseBlock);
2681 // Add the terminator and condition in the switch block.
2682 SwitchTerminatedBlock->setTerminator(Terminator);
2683 Block = SwitchTerminatedBlock;
2684 CFGBlock *LastBlock = addStmt(Terminator->getCond());
2686 // Finally, if the SwitchStmt contains a condition variable, add both the
2687 // SwitchStmt and the condition variable initialization to the CFG.
2688 if (VarDecl *VD = Terminator->getConditionVariable()) {
2689 if (Expr *Init = VD->getInit()) {
2691 appendStmt(Block, Terminator->getConditionVariableDeclStmt());
2692 LastBlock = addStmt(Init);
2699 static bool shouldAddCase(bool &switchExclusivelyCovered,
2700 const Expr::EvalResult *switchCond,
2706 bool addCase = false;
2708 if (!switchExclusivelyCovered) {
2709 if (switchCond->Val.isInt()) {
2710 // Evaluate the LHS of the case value.
2711 const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx);
2712 const llvm::APSInt &condInt = switchCond->Val.getInt();
2714 if (condInt == lhsInt) {
2716 switchExclusivelyCovered = true;
2718 else if (condInt < lhsInt) {
2719 if (const Expr *RHS = CS->getRHS()) {
2720 // Evaluate the RHS of the case value.
2721 const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx);
2722 if (V2 <= condInt) {
2724 switchExclusivelyCovered = true;
2735 CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) {
2736 // CaseStmts are essentially labels, so they are the first statement in a
2738 CFGBlock *TopBlock = 0, *LastBlock = 0;
2740 if (Stmt *Sub = CS->getSubStmt()) {
2741 // For deeply nested chains of CaseStmts, instead of doing a recursion
2742 // (which can blow out the stack), manually unroll and create blocks
2744 while (isa<CaseStmt>(Sub)) {
2745 CFGBlock *currentBlock = createBlock(false);
2746 currentBlock->setLabel(CS);
2749 addSuccessor(LastBlock, currentBlock);
2751 TopBlock = currentBlock;
2753 addSuccessor(SwitchTerminatedBlock,
2754 shouldAddCase(switchExclusivelyCovered, switchCond,
2756 ? currentBlock : 0);
2758 LastBlock = currentBlock;
2759 CS = cast<CaseStmt>(Sub);
2760 Sub = CS->getSubStmt();
2766 CFGBlock *CaseBlock = Block;
2768 CaseBlock = createBlock();
2770 // Cases statements partition blocks, so this is the top of the basic block we
2771 // were processing (the "case XXX:" is the label).
2772 CaseBlock->setLabel(CS);
2777 // Add this block to the list of successors for the block with the switch
2779 assert(SwitchTerminatedBlock);
2780 addSuccessor(SwitchTerminatedBlock,
2781 shouldAddCase(switchExclusivelyCovered, switchCond,
2785 // We set Block to NULL to allow lazy creation of a new block (if necessary)
2789 addSuccessor(LastBlock, CaseBlock);
2792 // This block is now the implicit successor of other blocks.
2799 CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) {
2800 if (Terminator->getSubStmt())
2801 addStmt(Terminator->getSubStmt());
2803 DefaultCaseBlock = Block;
2805 if (!DefaultCaseBlock)
2806 DefaultCaseBlock = createBlock();
2808 // Default statements partition blocks, so this is the top of the basic block
2809 // we were processing (the "default:" is the label).
2810 DefaultCaseBlock->setLabel(Terminator);
2815 // Unlike case statements, we don't add the default block to the successors
2816 // for the switch statement immediately. This is done when we finish
2817 // processing the switch statement. This allows for the default case
2818 // (including a fall-through to the code after the switch statement) to always
2819 // be the last successor of a switch-terminated block.
2821 // We set Block to NULL to allow lazy creation of a new block (if necessary)
2824 // This block is now the implicit successor of other blocks.
2825 Succ = DefaultCaseBlock;
2827 return DefaultCaseBlock;
2830 CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) {
2831 // "try"/"catch" is a control-flow statement. Thus we stop processing the
2833 CFGBlock *TrySuccessor = NULL;
2838 TrySuccessor = Block;
2839 } else TrySuccessor = Succ;
2841 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock;
2843 // Create a new block that will contain the try statement.
2844 CFGBlock *NewTryTerminatedBlock = createBlock(false);
2845 // Add the terminator in the try block.
2846 NewTryTerminatedBlock->setTerminator(Terminator);
2848 bool HasCatchAll = false;
2849 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) {
2850 // The code after the try is the implicit successor.
2851 Succ = TrySuccessor;
2852 CXXCatchStmt *CS = Terminator->getHandler(h);
2853 if (CS->getExceptionDecl() == 0) {
2857 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS);
2858 if (CatchBlock == 0)
2860 // Add this block to the list of successors for the block with the try
2862 addSuccessor(NewTryTerminatedBlock, CatchBlock);
2865 if (PrevTryTerminatedBlock)
2866 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock);
2868 addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
2871 // The code after the try is the implicit successor.
2872 Succ = TrySuccessor;
2874 // Save the current "try" context.
2875 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock);
2876 cfg->addTryDispatchBlock(TryTerminatedBlock);
2878 assert(Terminator->getTryBlock() && "try must contain a non-NULL body");
2880 return addStmt(Terminator->getTryBlock());
2883 CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) {
2884 // CXXCatchStmt are treated like labels, so they are the first statement in a
2887 // Save local scope position because in case of exception variable ScopePos
2888 // won't be restored when traversing AST.
2889 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2891 // Create local scope for possible exception variable.
2892 // Store scope position. Add implicit destructor.
2893 if (VarDecl *VD = CS->getExceptionDecl()) {
2894 LocalScope::const_iterator BeginScopePos = ScopePos;
2895 addLocalScopeForVarDecl(VD);
2896 addAutomaticObjDtors(ScopePos, BeginScopePos, CS);
2899 if (CS->getHandlerBlock())
2900 addStmt(CS->getHandlerBlock());
2902 CFGBlock *CatchBlock = Block;
2904 CatchBlock = createBlock();
2906 // CXXCatchStmt is more than just a label. They have semantic meaning
2907 // as well, as they implicitly "initialize" the catch variable. Add
2908 // it to the CFG as a CFGElement so that the control-flow of these
2909 // semantics gets captured.
2910 appendStmt(CatchBlock, CS);
2912 // Also add the CXXCatchStmt as a label, to mirror handling of regular
2914 CatchBlock->setLabel(CS);
2916 // Bail out if the CFG is bad.
2920 // We set Block to NULL to allow lazy creation of a new block (if necessary)
2926 CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) {
2927 // C++0x for-range statements are specified as [stmt.ranged]:
2930 // auto && __range = range-init;
2931 // for ( auto __begin = begin-expr,
2932 // __end = end-expr;
2933 // __begin != __end;
2935 // for-range-declaration = *__begin;
2940 // Save local scope position before the addition of the implicit variables.
2941 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2943 // Create local scopes and destructors for range, begin and end variables.
2944 if (Stmt *Range = S->getRangeStmt())
2945 addLocalScopeForStmt(Range);
2946 if (Stmt *BeginEnd = S->getBeginEndStmt())
2947 addLocalScopeForStmt(BeginEnd);
2948 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), S);
2950 LocalScope::const_iterator ContinueScopePos = ScopePos;
2952 // "for" is a control-flow statement. Thus we stop processing the current
2954 CFGBlock *LoopSuccessor = NULL;
2958 LoopSuccessor = Block;
2960 LoopSuccessor = Succ;
2962 // Save the current value for the break targets.
2963 // All breaks should go to the code following the loop.
2964 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
2965 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
2967 // The block for the __begin != __end expression.
2968 CFGBlock *ConditionBlock = createBlock(false);
2969 ConditionBlock->setTerminator(S);
2971 // Now add the actual condition to the condition block.
2972 if (Expr *C = S->getCond()) {
2973 Block = ConditionBlock;
2974 CFGBlock *BeginConditionBlock = addStmt(C);
2977 assert(BeginConditionBlock == ConditionBlock &&
2978 "condition block in for-range was unexpectedly complex");
2979 (void)BeginConditionBlock;
2982 // The condition block is the implicit successor for the loop body as well as
2983 // any code above the loop.
2984 Succ = ConditionBlock;
2986 // See if this is a known constant.
2987 TryResult KnownVal(true);
2990 KnownVal = tryEvaluateBool(S->getCond());
2992 // Now create the loop body.
2994 assert(S->getBody());
2996 // Save the current values for Block, Succ, and continue targets.
2997 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
2998 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
3000 // Generate increment code in its own basic block. This is the target of
3001 // continue statements.
3003 Succ = addStmt(S->getInc());
3004 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
3006 // The starting block for the loop increment is the block that should
3007 // represent the 'loop target' for looping back to the start of the loop.
3008 ContinueJumpTarget.block->setLoopTarget(S);
3010 // Finish up the increment block and prepare to start the loop body.
3017 // Add implicit scope and dtors for loop variable.
3018 addLocalScopeAndDtors(S->getLoopVarStmt());
3020 // Populate a new block to contain the loop body and loop variable.
3021 addStmt(S->getBody());
3024 CFGBlock *LoopVarStmtBlock = addStmt(S->getLoopVarStmt());
3028 // This new body block is a successor to our condition block.
3029 addSuccessor(ConditionBlock, KnownVal.isFalse() ? 0 : LoopVarStmtBlock);
3032 // Link up the condition block with the code that follows the loop (the
3034 addSuccessor(ConditionBlock, KnownVal.isTrue() ? 0 : LoopSuccessor);
3036 // Add the initialization statements.
3037 Block = createBlock();
3038 addStmt(S->getBeginEndStmt());
3039 return addStmt(S->getRangeStmt());
3042 CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E,
3043 AddStmtChoice asc) {
3044 if (BuildOpts.AddTemporaryDtors) {
3045 // If adding implicit destructors visit the full expression for adding
3046 // destructors of temporaries.
3047 VisitForTemporaryDtors(E->getSubExpr());
3049 // Full expression has to be added as CFGStmt so it will be sequenced
3050 // before destructors of it's temporaries.
3051 asc = asc.withAlwaysAdd(true);
3053 return Visit(E->getSubExpr(), asc);
3056 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
3057 AddStmtChoice asc) {
3058 if (asc.alwaysAdd(*this, E)) {
3060 appendStmt(Block, E);
3062 // We do not want to propagate the AlwaysAdd property.
3063 asc = asc.withAlwaysAdd(false);
3065 return Visit(E->getSubExpr(), asc);
3068 CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C,
3069 AddStmtChoice asc) {
3071 appendStmt(Block, C);
3073 return VisitChildren(C);
3076 CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
3077 AddStmtChoice asc) {
3078 if (asc.alwaysAdd(*this, E)) {
3080 appendStmt(Block, E);
3081 // We do not want to propagate the AlwaysAdd property.
3082 asc = asc.withAlwaysAdd(false);
3084 return Visit(E->getSubExpr(), asc);
3087 CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
3088 AddStmtChoice asc) {
3090 appendStmt(Block, C);
3091 return VisitChildren(C);
3094 CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E,
3095 AddStmtChoice asc) {
3096 if (asc.alwaysAdd(*this, E)) {
3098 appendStmt(Block, E);
3100 return Visit(E->getSubExpr(), AddStmtChoice());
3103 CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) {
3104 // Lazily create the indirect-goto dispatch block if there isn't one already.
3105 CFGBlock *IBlock = cfg->getIndirectGotoBlock();
3108 IBlock = createBlock(false);
3109 cfg->setIndirectGotoBlock(IBlock);
3112 // IndirectGoto is a control-flow statement. Thus we stop processing the
3113 // current block and create a new one.
3117 Block = createBlock(false);
3118 Block->setTerminator(I);
3119 addSuccessor(Block, IBlock);
3120 return addStmt(I->getTarget());
3123 CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) {
3124 assert(BuildOpts.AddImplicitDtors && BuildOpts.AddTemporaryDtors);
3131 switch (E->getStmtClass()) {
3133 return VisitChildrenForTemporaryDtors(E);
3135 case Stmt::BinaryOperatorClass:
3136 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E));
3138 case Stmt::CXXBindTemporaryExprClass:
3139 return VisitCXXBindTemporaryExprForTemporaryDtors(
3140 cast<CXXBindTemporaryExpr>(E), BindToTemporary);
3142 case Stmt::BinaryConditionalOperatorClass:
3143 case Stmt::ConditionalOperatorClass:
3144 return VisitConditionalOperatorForTemporaryDtors(
3145 cast<AbstractConditionalOperator>(E), BindToTemporary);
3147 case Stmt::ImplicitCastExprClass:
3148 // For implicit cast we want BindToTemporary to be passed further.
3149 E = cast<CastExpr>(E)->getSubExpr();
3152 case Stmt::ParenExprClass:
3153 E = cast<ParenExpr>(E)->getSubExpr();
3156 case Stmt::MaterializeTemporaryExprClass:
3157 E = cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr();
3162 CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) {
3163 // When visiting children for destructors we want to visit them in reverse
3164 // order that they will appear in the CFG. Because the CFG is built
3165 // bottom-up, this means we visit them in their natural order, which
3166 // reverses them in the CFG.
3167 CFGBlock *B = Block;
3168 for (Stmt::child_range I = E->children(); I; ++I) {
3169 if (Stmt *Child = *I)
3170 if (CFGBlock *R = VisitForTemporaryDtors(Child))
3176 CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) {
3177 if (E->isLogicalOp()) {
3178 // Destructors for temporaries in LHS expression should be called after
3179 // those for RHS expression. Even if this will unnecessarily create a block,
3180 // this block will be used at least by the full expression.
3182 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS());
3186 Succ = ConfluenceBlock;
3188 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS());
3194 // If RHS expression did produce destructors we need to connect created
3195 // blocks to CFG in same manner as for binary operator itself.
3196 CFGBlock *LHSBlock = createBlock(false);
3197 LHSBlock->setTerminator(CFGTerminator(E, true));
3199 // For binary operator LHS block is before RHS in list of predecessors
3200 // of ConfluenceBlock.
3201 std::reverse(ConfluenceBlock->pred_begin(),
3202 ConfluenceBlock->pred_end());
3204 // See if this is a known constant.
3205 TryResult KnownVal = tryEvaluateBool(E->getLHS());
3206 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr))
3209 // Link LHSBlock with RHSBlock exactly the same way as for binary operator
3211 if (E->getOpcode() == BO_LOr) {
3212 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock);
3213 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock);
3215 assert (E->getOpcode() == BO_LAnd);
3216 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock);
3217 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock);
3224 Block = ConfluenceBlock;
3225 return ConfluenceBlock;
3228 if (E->isAssignmentOp()) {
3229 // For assignment operator (=) LHS expression is visited
3230 // before RHS expression. For destructors visit them in reverse order.
3231 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS());
3232 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS());
3233 return LHSBlock ? LHSBlock : RHSBlock;
3236 // For any other binary operator RHS expression is visited before
3237 // LHS expression (order of children). For destructors visit them in reverse
3239 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS());
3240 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS());
3241 return RHSBlock ? RHSBlock : LHSBlock;
3244 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors(
3245 CXXBindTemporaryExpr *E, bool BindToTemporary) {
3246 // First add destructors for temporaries in subexpression.
3247 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr());
3248 if (!BindToTemporary) {
3249 // If lifetime of temporary is not prolonged (by assigning to constant
3250 // reference) add destructor for it.
3252 // If the destructor is marked as a no-return destructor, we need to create
3253 // a new block for the destructor which does not have as a successor
3254 // anything built thus far. Control won't flow out of this block.
3255 const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor();
3256 if (Dtor->isNoReturn())
3257 Block = createNoReturnBlock();
3261 appendTemporaryDtor(Block, E);
3267 CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors(
3268 AbstractConditionalOperator *E, bool BindToTemporary) {
3269 // First add destructors for condition expression. Even if this will
3270 // unnecessarily create a block, this block will be used at least by the full
3273 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond());
3276 if (BinaryConditionalOperator *BCO
3277 = dyn_cast<BinaryConditionalOperator>(E)) {
3278 ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon());
3283 // Try to add block with destructors for LHS expression.
3284 CFGBlock *LHSBlock = NULL;
3285 Succ = ConfluenceBlock;
3287 LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary);
3291 // Try to add block with destructors for RHS expression;
3292 Succ = ConfluenceBlock;
3294 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(),
3299 if (!RHSBlock && !LHSBlock) {
3300 // If neither LHS nor RHS expression had temporaries to destroy don't create
3302 Block = ConfluenceBlock;
3306 Block = createBlock(false);
3307 Block->setTerminator(CFGTerminator(E, true));
3309 // See if this is a known constant.
3310 const TryResult &KnownVal = tryEvaluateBool(E->getCond());
3313 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock);
3314 } else if (KnownVal.isFalse()) {
3315 addSuccessor(Block, NULL);
3317 addSuccessor(Block, ConfluenceBlock);
3318 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end());
3322 RHSBlock = ConfluenceBlock;
3323 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock);
3328 } // end anonymous namespace
3330 /// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has
3331 /// no successors or predecessors. If this is the first block created in the
3332 /// CFG, it is automatically set to be the Entry and Exit of the CFG.
3333 CFGBlock *CFG::createBlock() {
3334 bool first_block = begin() == end();
3336 // Create the block.
3337 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>();
3338 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this);
3339 Blocks.push_back(Mem, BlkBVC);
3341 // If this is the first block, set it as the Entry and Exit.
3343 Entry = Exit = &back();
3345 // Return the block.
3349 /// buildCFG - Constructs a CFG from an AST. Ownership of the returned
3350 /// CFG is returned to the caller.
3351 CFG* CFG::buildCFG(const Decl *D, Stmt *Statement, ASTContext *C,
3352 const BuildOptions &BO) {
3353 CFGBuilder Builder(C, BO);
3354 return Builder.buildCFG(D, Statement);
3357 const CXXDestructorDecl *
3358 CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const {
3359 switch (getKind()) {
3360 case CFGElement::Statement:
3361 case CFGElement::Initializer:
3362 llvm_unreachable("getDestructorDecl should only be used with "
3364 case CFGElement::AutomaticObjectDtor: {
3365 const VarDecl *var = castAs<CFGAutomaticObjDtor>().getVarDecl();
3366 QualType ty = var->getType();
3367 ty = ty.getNonReferenceType();
3368 while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) {
3369 ty = arrayType->getElementType();
3371 const RecordType *recordType = ty->getAs<RecordType>();
3372 const CXXRecordDecl *classDecl =
3373 cast<CXXRecordDecl>(recordType->getDecl());
3374 return classDecl->getDestructor();
3376 case CFGElement::TemporaryDtor: {
3377 const CXXBindTemporaryExpr *bindExpr =
3378 castAs<CFGTemporaryDtor>().getBindTemporaryExpr();
3379 const CXXTemporary *temp = bindExpr->getTemporary();
3380 return temp->getDestructor();
3382 case CFGElement::BaseDtor:
3383 case CFGElement::MemberDtor:
3385 // Not yet supported.
3388 llvm_unreachable("getKind() returned bogus value");
3391 bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const {
3392 if (const CXXDestructorDecl *DD = getDestructorDecl(astContext))
3393 return DD->isNoReturn();
3397 //===----------------------------------------------------------------------===//
3398 // CFG: Queries for BlkExprs.
3399 //===----------------------------------------------------------------------===//
3402 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy;
3405 static void FindSubExprAssignments(const Stmt *S,
3406 llvm::SmallPtrSet<const Expr*,50>& Set) {
3410 for (Stmt::const_child_range I = S->children(); I; ++I) {
3411 const Stmt *child = *I;
3415 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(child))
3416 if (B->isAssignmentOp()) Set.insert(B);
3418 FindSubExprAssignments(child, Set);
3422 static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) {
3423 BlkExprMapTy* M = new BlkExprMapTy();
3425 // Look for assignments that are used as subexpressions. These are the only
3426 // assignments that we want to *possibly* register as a block-level
3427 // expression. Basically, if an assignment occurs both in a subexpression and
3428 // at the block-level, it is a block-level expression.
3429 llvm::SmallPtrSet<const Expr*,50> SubExprAssignments;
3431 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I)
3432 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI)
3433 if (Optional<CFGStmt> S = BI->getAs<CFGStmt>())
3434 FindSubExprAssignments(S->getStmt(), SubExprAssignments);
3436 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) {
3438 // Iterate over the statements again on identify the Expr* and Stmt* at the
3439 // block-level that are block-level expressions.
3441 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) {
3442 Optional<CFGStmt> CS = BI->getAs<CFGStmt>();
3445 if (const Expr *Exp = dyn_cast<Expr>(CS->getStmt())) {
3446 assert((Exp->IgnoreParens() == Exp) && "No parens on block-level exps");
3448 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) {
3449 // Assignment expressions that are not nested within another
3450 // expression are really "statements" whose value is never used by
3451 // another expression.
3452 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp))
3454 } else if (const StmtExpr *SE = dyn_cast<StmtExpr>(Exp)) {
3455 // Special handling for statement expressions. The last statement in
3456 // the statement expression is also a block-level expr.
3457 const CompoundStmt *C = SE->getSubStmt();
3458 if (!C->body_empty()) {
3459 const Stmt *Last = C->body_back();
3460 if (const Expr *LastEx = dyn_cast<Expr>(Last))
3461 Last = LastEx->IgnoreParens();
3462 unsigned x = M->size();
3467 unsigned x = M->size();
3472 // Look at terminators. The condition is a block-level expression.
3474 Stmt *S = (*I)->getTerminatorCondition();
3476 if (S && M->find(S) == M->end()) {
3477 unsigned x = M->size();
3485 CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt *S) {
3487 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); }
3489 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap);
3490 BlkExprMapTy::iterator I = M->find(S);
3491 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second);
3494 unsigned CFG::getNumBlkExprs() {
3495 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap))
3498 // We assume callers interested in the number of BlkExprs will want
3499 // the map constructed if it doesn't already exist.
3500 BlkExprMap = (void*) PopulateBlkExprMap(*this);
3501 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size();
3504 //===----------------------------------------------------------------------===//
3505 // Filtered walking of the CFG.
3506 //===----------------------------------------------------------------------===//
3508 bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F,
3509 const CFGBlock *From, const CFGBlock *To) {
3511 if (To && F.IgnoreDefaultsWithCoveredEnums) {
3512 // If the 'To' has no label or is labeled but the label isn't a
3513 // CaseStmt then filter this edge.
3514 if (const SwitchStmt *S =
3515 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) {
3516 if (S->isAllEnumCasesCovered()) {
3517 const Stmt *L = To->getLabel();
3518 if (!L || !isa<CaseStmt>(L))
3527 //===----------------------------------------------------------------------===//
3528 // Cleanup: CFG dstor.
3529 //===----------------------------------------------------------------------===//
3532 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap);
3535 //===----------------------------------------------------------------------===//
3536 // CFG pretty printing
3537 //===----------------------------------------------------------------------===//
3541 class StmtPrinterHelper : public PrinterHelper {
3542 typedef llvm::DenseMap<const Stmt*,std::pair<unsigned,unsigned> > StmtMapTy;
3543 typedef llvm::DenseMap<const Decl*,std::pair<unsigned,unsigned> > DeclMapTy;
3546 signed currentBlock;
3548 const LangOptions &LangOpts;
3551 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO)
3552 : currentBlock(0), currStmt(0), LangOpts(LO)
3554 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) {
3556 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ;
3557 BI != BEnd; ++BI, ++j ) {
3558 if (Optional<CFGStmt> SE = BI->getAs<CFGStmt>()) {
3559 const Stmt *stmt= SE->getStmt();
3560 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j);
3563 switch (stmt->getStmtClass()) {
3564 case Stmt::DeclStmtClass:
3565 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P;
3567 case Stmt::IfStmtClass: {
3568 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable();
3573 case Stmt::ForStmtClass: {
3574 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable();
3579 case Stmt::WhileStmtClass: {
3580 const VarDecl *var =
3581 cast<WhileStmt>(stmt)->getConditionVariable();
3586 case Stmt::SwitchStmtClass: {
3587 const VarDecl *var =
3588 cast<SwitchStmt>(stmt)->getConditionVariable();
3593 case Stmt::CXXCatchStmtClass: {
3594 const VarDecl *var =
3595 cast<CXXCatchStmt>(stmt)->getExceptionDecl();
3609 virtual ~StmtPrinterHelper() {}
3611 const LangOptions &getLangOpts() const { return LangOpts; }
3612 void setBlockID(signed i) { currentBlock = i; }
3613 void setStmtID(unsigned i) { currStmt = i; }
3615 virtual bool handledStmt(Stmt *S, raw_ostream &OS) {
3616 StmtMapTy::iterator I = StmtMap.find(S);
3618 if (I == StmtMap.end())
3621 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
3622 && I->second.second == currStmt) {
3626 OS << "[B" << I->second.first << "." << I->second.second << "]";
3630 bool handleDecl(const Decl *D, raw_ostream &OS) {
3631 DeclMapTy::iterator I = DeclMap.find(D);
3633 if (I == DeclMap.end())
3636 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
3637 && I->second.second == currStmt) {
3641 OS << "[B" << I->second.first << "." << I->second.second << "]";
3645 } // end anonymous namespace
3649 class CFGBlockTerminatorPrint
3650 : public StmtVisitor<CFGBlockTerminatorPrint,void> {
3653 StmtPrinterHelper* Helper;
3654 PrintingPolicy Policy;
3656 CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper,
3657 const PrintingPolicy &Policy)
3658 : OS(os), Helper(helper), Policy(Policy) {}
3660 void VisitIfStmt(IfStmt *I) {
3662 I->getCond()->printPretty(OS,Helper,Policy);
3666 void VisitStmt(Stmt *Terminator) {
3667 Terminator->printPretty(OS, Helper, Policy);
3670 void VisitDeclStmt(DeclStmt *DS) {
3671 VarDecl *VD = cast<VarDecl>(DS->getSingleDecl());
3672 OS << "static init " << VD->getName();
3675 void VisitForStmt(ForStmt *F) {
3680 if (Stmt *C = F->getCond())
3681 C->printPretty(OS, Helper, Policy);
3688 void VisitWhileStmt(WhileStmt *W) {
3690 if (Stmt *C = W->getCond())
3691 C->printPretty(OS, Helper, Policy);
3694 void VisitDoStmt(DoStmt *D) {
3695 OS << "do ... while ";
3696 if (Stmt *C = D->getCond())
3697 C->printPretty(OS, Helper, Policy);
3700 void VisitSwitchStmt(SwitchStmt *Terminator) {
3702 Terminator->getCond()->printPretty(OS, Helper, Policy);
3705 void VisitCXXTryStmt(CXXTryStmt *CS) {
3709 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) {
3710 C->getCond()->printPretty(OS, Helper, Policy);
3711 OS << " ? ... : ...";
3714 void VisitChooseExpr(ChooseExpr *C) {
3715 OS << "__builtin_choose_expr( ";
3716 C->getCond()->printPretty(OS, Helper, Policy);
3720 void VisitIndirectGotoStmt(IndirectGotoStmt *I) {
3722 I->getTarget()->printPretty(OS, Helper, Policy);
3725 void VisitBinaryOperator(BinaryOperator* B) {
3726 if (!B->isLogicalOp()) {
3731 B->getLHS()->printPretty(OS, Helper, Policy);
3733 switch (B->getOpcode()) {
3741 llvm_unreachable("Invalid logical operator.");
3745 void VisitExpr(Expr *E) {
3746 E->printPretty(OS, Helper, Policy);
3749 } // end anonymous namespace
3751 static void print_elem(raw_ostream &OS, StmtPrinterHelper* Helper,
3752 const CFGElement &E) {
3753 if (Optional<CFGStmt> CS = E.getAs<CFGStmt>()) {
3754 const Stmt *S = CS->getStmt();
3758 // special printing for statement-expressions.
3759 if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) {
3760 const CompoundStmt *Sub = SE->getSubStmt();
3762 if (Sub->children()) {
3764 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS);
3769 // special printing for comma expressions.
3770 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) {
3771 if (B->getOpcode() == BO_Comma) {
3773 Helper->handledStmt(B->getRHS(),OS);
3779 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts()));
3781 if (isa<CXXOperatorCallExpr>(S)) {
3782 OS << " (OperatorCall)";
3784 else if (isa<CXXBindTemporaryExpr>(S)) {
3785 OS << " (BindTemporary)";
3787 else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) {
3788 OS << " (CXXConstructExpr, " << CCE->getType().getAsString() << ")";
3790 else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) {
3791 OS << " (" << CE->getStmtClassName() << ", "
3792 << CE->getCastKindName()
3793 << ", " << CE->getType().getAsString()
3797 // Expressions need a newline.
3801 } else if (Optional<CFGInitializer> IE = E.getAs<CFGInitializer>()) {
3802 const CXXCtorInitializer *I = IE->getInitializer();
3803 if (I->isBaseInitializer())
3804 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName();
3805 else OS << I->getAnyMember()->getName();
3808 if (Expr *IE = I->getInit())
3809 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts()));
3812 if (I->isBaseInitializer())
3813 OS << " (Base initializer)\n";
3814 else OS << " (Member initializer)\n";
3816 } else if (Optional<CFGAutomaticObjDtor> DE =
3817 E.getAs<CFGAutomaticObjDtor>()) {
3818 const VarDecl *VD = DE->getVarDecl();
3819 Helper->handleDecl(VD, OS);
3821 const Type* T = VD->getType().getTypePtr();
3822 if (const ReferenceType* RT = T->getAs<ReferenceType>())
3823 T = RT->getPointeeType().getTypePtr();
3824 T = T->getBaseElementTypeUnsafe();
3826 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()";
3827 OS << " (Implicit destructor)\n";
3829 } else if (Optional<CFGBaseDtor> BE = E.getAs<CFGBaseDtor>()) {
3830 const CXXBaseSpecifier *BS = BE->getBaseSpecifier();
3831 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()";
3832 OS << " (Base object destructor)\n";
3834 } else if (Optional<CFGMemberDtor> ME = E.getAs<CFGMemberDtor>()) {
3835 const FieldDecl *FD = ME->getFieldDecl();
3836 const Type *T = FD->getType()->getBaseElementTypeUnsafe();
3837 OS << "this->" << FD->getName();
3838 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()";
3839 OS << " (Member object destructor)\n";
3841 } else if (Optional<CFGTemporaryDtor> TE = E.getAs<CFGTemporaryDtor>()) {
3842 const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr();
3843 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()";
3844 OS << " (Temporary object destructor)\n";
3848 static void print_block(raw_ostream &OS, const CFG* cfg,
3850 StmtPrinterHelper* Helper, bool print_edges,
3854 Helper->setBlockID(B.getBlockID());
3856 // Print the header.
3858 OS.changeColor(raw_ostream::YELLOW, true);
3860 OS << "\n [B" << B.getBlockID();
3862 if (&B == &cfg->getEntry())
3863 OS << " (ENTRY)]\n";
3864 else if (&B == &cfg->getExit())
3866 else if (&B == cfg->getIndirectGotoBlock())
3867 OS << " (INDIRECT GOTO DISPATCH)]\n";
3874 // Print the label of this block.
3875 if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) {
3880 if (LabelStmt *L = dyn_cast<LabelStmt>(Label))
3882 else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) {
3884 C->getLHS()->printPretty(OS, Helper,
3885 PrintingPolicy(Helper->getLangOpts()));
3888 C->getRHS()->printPretty(OS, Helper,
3889 PrintingPolicy(Helper->getLangOpts()));
3891 } else if (isa<DefaultStmt>(Label))
3893 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) {
3895 if (CS->getExceptionDecl())
3896 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()),
3903 llvm_unreachable("Invalid label statement in CFGBlock.");
3908 // Iterate through the statements in the block and print them.
3911 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ;
3912 I != E ; ++I, ++j ) {
3914 // Print the statement # in the basic block and the statement itself.
3918 OS << llvm::format("%3d", j) << ": ";
3921 Helper->setStmtID(j);
3923 print_elem(OS, Helper, *I);
3926 // Print the terminator of this block.
3927 if (B.getTerminator()) {
3929 OS.changeColor(raw_ostream::GREEN);
3933 if (Helper) Helper->setBlockID(-1);
3935 PrintingPolicy PP(Helper ? Helper->getLangOpts() : LangOptions());
3936 CFGBlockTerminatorPrint TPrinter(OS, Helper, PP);
3937 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt()));
3945 // Print the predecessors of this block.
3946 if (!B.pred_empty()) {
3947 const raw_ostream::Colors Color = raw_ostream::BLUE;
3949 OS.changeColor(Color);
3953 OS << '(' << B.pred_size() << "):";
3957 OS.changeColor(Color);
3959 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end();
3965 OS << " B" << (*I)->getBlockID();
3974 // Print the successors of this block.
3975 if (!B.succ_empty()) {
3976 const raw_ostream::Colors Color = raw_ostream::MAGENTA;
3978 OS.changeColor(Color);
3982 OS << '(' << B.succ_size() << "):";
3986 OS.changeColor(Color);
3988 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end();
3995 OS << " B" << (*I)->getBlockID();
4008 /// dump - A simple pretty printer of a CFG that outputs to stderr.
4009 void CFG::dump(const LangOptions &LO, bool ShowColors) const {
4010 print(llvm::errs(), LO, ShowColors);
4013 /// print - A simple pretty printer of a CFG that outputs to an ostream.
4014 void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const {
4015 StmtPrinterHelper Helper(this, LO);
4017 // Print the entry block.
4018 print_block(OS, this, getEntry(), &Helper, true, ShowColors);
4020 // Iterate through the CFGBlocks and print them one by one.
4021 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) {
4022 // Skip the entry block, because we already printed it.
4023 if (&(**I) == &getEntry() || &(**I) == &getExit())
4026 print_block(OS, this, **I, &Helper, true, ShowColors);
4029 // Print the exit block.
4030 print_block(OS, this, getExit(), &Helper, true, ShowColors);
4035 /// dump - A simply pretty printer of a CFGBlock that outputs to stderr.
4036 void CFGBlock::dump(const CFG* cfg, const LangOptions &LO,
4037 bool ShowColors) const {
4038 print(llvm::errs(), cfg, LO, ShowColors);
4041 /// print - A simple pretty printer of a CFGBlock that outputs to an ostream.
4042 /// Generally this will only be called from CFG::print.
4043 void CFGBlock::print(raw_ostream &OS, const CFG* cfg,
4044 const LangOptions &LO, bool ShowColors) const {
4045 StmtPrinterHelper Helper(cfg, LO);
4046 print_block(OS, cfg, *this, &Helper, true, ShowColors);
4050 /// printTerminator - A simple pretty printer of the terminator of a CFGBlock.
4051 void CFGBlock::printTerminator(raw_ostream &OS,
4052 const LangOptions &LO) const {
4053 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO));
4054 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt()));
4057 Stmt *CFGBlock::getTerminatorCondition() {
4058 Stmt *Terminator = this->Terminator;
4064 switch (Terminator->getStmtClass()) {
4068 case Stmt::ForStmtClass:
4069 E = cast<ForStmt>(Terminator)->getCond();
4072 case Stmt::WhileStmtClass:
4073 E = cast<WhileStmt>(Terminator)->getCond();
4076 case Stmt::DoStmtClass:
4077 E = cast<DoStmt>(Terminator)->getCond();
4080 case Stmt::IfStmtClass:
4081 E = cast<IfStmt>(Terminator)->getCond();
4084 case Stmt::ChooseExprClass:
4085 E = cast<ChooseExpr>(Terminator)->getCond();
4088 case Stmt::IndirectGotoStmtClass:
4089 E = cast<IndirectGotoStmt>(Terminator)->getTarget();
4092 case Stmt::SwitchStmtClass:
4093 E = cast<SwitchStmt>(Terminator)->getCond();
4096 case Stmt::BinaryConditionalOperatorClass:
4097 E = cast<BinaryConditionalOperator>(Terminator)->getCond();
4100 case Stmt::ConditionalOperatorClass:
4101 E = cast<ConditionalOperator>(Terminator)->getCond();
4104 case Stmt::BinaryOperatorClass: // '&&' and '||'
4105 E = cast<BinaryOperator>(Terminator)->getLHS();
4108 case Stmt::ObjCForCollectionStmtClass:
4112 return E ? E->IgnoreParens() : NULL;
4115 //===----------------------------------------------------------------------===//
4116 // CFG Graphviz Visualization
4117 //===----------------------------------------------------------------------===//
4121 static StmtPrinterHelper* GraphHelper;
4124 void CFG::viewCFG(const LangOptions &LO) const {
4126 StmtPrinterHelper H(this, LO);
4128 llvm::ViewGraph(this,"CFG");
4135 struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits {
4137 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
4139 static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) {
4142 std::string OutSStr;
4143 llvm::raw_string_ostream Out(OutSStr);
4144 print_block(Out,Graph, *Node, GraphHelper, false, false);
4145 std::string& OutStr = Out.str();
4147 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
4149 // Process string output to make it nicer...
4150 for (unsigned i = 0; i != OutStr.length(); ++i)
4151 if (OutStr[i] == '\n') { // Left justify
4153 OutStr.insert(OutStr.begin()+i+1, 'l');
4162 } // end namespace llvm