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 case Stmt::CXXDefaultInitExprClass:
1089 // FIXME: The expression inside a CXXDefaultArgExpr is owned by the
1090 // called function's declaration, not by the caller. If we simply add
1091 // this expression to the CFG, we could end up with the same Expr
1092 // appearing multiple times.
1093 // PR13385 / <rdar://problem/12156507>
1095 // It's likewise possible for multiple CXXDefaultInitExprs for the same
1096 // expression to be used in the same function (through aggregate
1098 return VisitStmt(S, asc);
1100 case Stmt::CXXBindTemporaryExprClass:
1101 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc);
1103 case Stmt::CXXConstructExprClass:
1104 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc);
1106 case Stmt::CXXFunctionalCastExprClass:
1107 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc);
1109 case Stmt::CXXTemporaryObjectExprClass:
1110 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc);
1112 case Stmt::CXXThrowExprClass:
1113 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S));
1115 case Stmt::CXXTryStmtClass:
1116 return VisitCXXTryStmt(cast<CXXTryStmt>(S));
1118 case Stmt::CXXForRangeStmtClass:
1119 return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S));
1121 case Stmt::DeclStmtClass:
1122 return VisitDeclStmt(cast<DeclStmt>(S));
1124 case Stmt::DefaultStmtClass:
1125 return VisitDefaultStmt(cast<DefaultStmt>(S));
1127 case Stmt::DoStmtClass:
1128 return VisitDoStmt(cast<DoStmt>(S));
1130 case Stmt::ForStmtClass:
1131 return VisitForStmt(cast<ForStmt>(S));
1133 case Stmt::GotoStmtClass:
1134 return VisitGotoStmt(cast<GotoStmt>(S));
1136 case Stmt::IfStmtClass:
1137 return VisitIfStmt(cast<IfStmt>(S));
1139 case Stmt::ImplicitCastExprClass:
1140 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc);
1142 case Stmt::IndirectGotoStmtClass:
1143 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S));
1145 case Stmt::LabelStmtClass:
1146 return VisitLabelStmt(cast<LabelStmt>(S));
1148 case Stmt::LambdaExprClass:
1149 return VisitLambdaExpr(cast<LambdaExpr>(S), asc);
1151 case Stmt::MemberExprClass:
1152 return VisitMemberExpr(cast<MemberExpr>(S), asc);
1154 case Stmt::NullStmtClass:
1157 case Stmt::ObjCAtCatchStmtClass:
1158 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S));
1160 case Stmt::ObjCAutoreleasePoolStmtClass:
1161 return VisitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(S));
1163 case Stmt::ObjCAtSynchronizedStmtClass:
1164 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S));
1166 case Stmt::ObjCAtThrowStmtClass:
1167 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S));
1169 case Stmt::ObjCAtTryStmtClass:
1170 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S));
1172 case Stmt::ObjCForCollectionStmtClass:
1173 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S));
1175 case Stmt::OpaqueValueExprClass:
1178 case Stmt::PseudoObjectExprClass:
1179 return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S));
1181 case Stmt::ReturnStmtClass:
1182 return VisitReturnStmt(cast<ReturnStmt>(S));
1184 case Stmt::UnaryExprOrTypeTraitExprClass:
1185 return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S),
1188 case Stmt::StmtExprClass:
1189 return VisitStmtExpr(cast<StmtExpr>(S), asc);
1191 case Stmt::SwitchStmtClass:
1192 return VisitSwitchStmt(cast<SwitchStmt>(S));
1194 case Stmt::UnaryOperatorClass:
1195 return VisitUnaryOperator(cast<UnaryOperator>(S), asc);
1197 case Stmt::WhileStmtClass:
1198 return VisitWhileStmt(cast<WhileStmt>(S));
1202 CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) {
1203 if (asc.alwaysAdd(*this, S)) {
1205 appendStmt(Block, S);
1208 return VisitChildren(S);
1211 /// VisitChildren - Visit the children of a Stmt.
1212 CFGBlock *CFGBuilder::VisitChildren(Stmt *S) {
1213 CFGBlock *B = Block;
1215 // Visit the children in their reverse order so that they appear in
1216 // left-to-right (natural) order in the CFG.
1217 reverse_children RChildren(S);
1218 for (reverse_children::iterator I = RChildren.begin(), E = RChildren.end();
1220 if (Stmt *Child = *I)
1221 if (CFGBlock *R = Visit(Child))
1227 CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A,
1228 AddStmtChoice asc) {
1229 AddressTakenLabels.insert(A->getLabel());
1231 if (asc.alwaysAdd(*this, A)) {
1233 appendStmt(Block, A);
1239 CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U,
1240 AddStmtChoice asc) {
1241 if (asc.alwaysAdd(*this, U)) {
1243 appendStmt(Block, U);
1246 return Visit(U->getSubExpr(), AddStmtChoice());
1249 CFGBlock *CFGBuilder::VisitLogicalOperator(BinaryOperator *B) {
1250 CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
1251 appendStmt(ConfluenceBlock, B);
1256 return VisitLogicalOperator(B, 0, ConfluenceBlock, ConfluenceBlock).first;
1259 std::pair<CFGBlock*, CFGBlock*>
1260 CFGBuilder::VisitLogicalOperator(BinaryOperator *B,
1262 CFGBlock *TrueBlock,
1263 CFGBlock *FalseBlock) {
1265 // Introspect the RHS. If it is a nested logical operation, we recursively
1266 // build the CFG using this function. Otherwise, resort to default
1267 // CFG construction behavior.
1268 Expr *RHS = B->getRHS()->IgnoreParens();
1269 CFGBlock *RHSBlock, *ExitBlock;
1272 if (BinaryOperator *B_RHS = dyn_cast<BinaryOperator>(RHS))
1273 if (B_RHS->isLogicalOp()) {
1274 llvm::tie(RHSBlock, ExitBlock) =
1275 VisitLogicalOperator(B_RHS, Term, TrueBlock, FalseBlock);
1279 // The RHS is not a nested logical operation. Don't push the terminator
1280 // down further, but instead visit RHS and construct the respective
1281 // pieces of the CFG, and link up the RHSBlock with the terminator
1282 // we have been provided.
1283 ExitBlock = RHSBlock = createBlock(false);
1286 assert(TrueBlock == FalseBlock);
1287 addSuccessor(RHSBlock, TrueBlock);
1290 RHSBlock->setTerminator(Term);
1291 TryResult KnownVal = tryEvaluateBool(RHS);
1292 addSuccessor(RHSBlock, KnownVal.isFalse() ? NULL : TrueBlock);
1293 addSuccessor(RHSBlock, KnownVal.isTrue() ? NULL : FalseBlock);
1297 RHSBlock = addStmt(RHS);
1302 return std::make_pair((CFGBlock*)0, (CFGBlock*)0);
1304 // Generate the blocks for evaluating the LHS.
1305 Expr *LHS = B->getLHS()->IgnoreParens();
1307 if (BinaryOperator *B_LHS = dyn_cast<BinaryOperator>(LHS))
1308 if (B_LHS->isLogicalOp()) {
1309 if (B->getOpcode() == BO_LOr)
1310 FalseBlock = RHSBlock;
1312 TrueBlock = RHSBlock;
1314 // For the LHS, treat 'B' as the terminator that we want to sink
1315 // into the nested branch. The RHS always gets the top-most
1317 return VisitLogicalOperator(B_LHS, B, TrueBlock, FalseBlock);
1320 // Create the block evaluating the LHS.
1321 // This contains the '&&' or '||' as the terminator.
1322 CFGBlock *LHSBlock = createBlock(false);
1323 LHSBlock->setTerminator(B);
1326 CFGBlock *EntryLHSBlock = addStmt(LHS);
1329 return std::make_pair((CFGBlock*)0, (CFGBlock*)0);
1331 // See if this is a known constant.
1332 TryResult KnownVal = tryEvaluateBool(LHS);
1334 // Now link the LHSBlock with RHSBlock.
1335 if (B->getOpcode() == BO_LOr) {
1336 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : TrueBlock);
1337 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : RHSBlock);
1339 assert(B->getOpcode() == BO_LAnd);
1340 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock);
1341 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : FalseBlock);
1344 return std::make_pair(EntryLHSBlock, ExitBlock);
1348 CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B,
1349 AddStmtChoice asc) {
1351 if (B->isLogicalOp())
1352 return VisitLogicalOperator(B);
1354 if (B->getOpcode() == BO_Comma) { // ,
1356 appendStmt(Block, B);
1357 addStmt(B->getRHS());
1358 return addStmt(B->getLHS());
1361 if (B->isAssignmentOp()) {
1362 if (asc.alwaysAdd(*this, B)) {
1364 appendStmt(Block, B);
1367 return Visit(B->getRHS());
1370 if (asc.alwaysAdd(*this, B)) {
1372 appendStmt(Block, B);
1375 CFGBlock *RBlock = Visit(B->getRHS());
1376 CFGBlock *LBlock = Visit(B->getLHS());
1377 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr
1378 // containing a DoStmt, and the LHS doesn't create a new block, then we should
1379 // return RBlock. Otherwise we'll incorrectly return NULL.
1380 return (LBlock ? LBlock : RBlock);
1383 CFGBlock *CFGBuilder::VisitNoRecurse(Expr *E, AddStmtChoice asc) {
1384 if (asc.alwaysAdd(*this, E)) {
1386 appendStmt(Block, E);
1391 CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) {
1392 // "break" is a control-flow statement. Thus we stop processing the current
1397 // Now create a new block that ends with the break statement.
1398 Block = createBlock(false);
1399 Block->setTerminator(B);
1401 // If there is no target for the break, then we are looking at an incomplete
1402 // AST. This means that the CFG cannot be constructed.
1403 if (BreakJumpTarget.block) {
1404 addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B);
1405 addSuccessor(Block, BreakJumpTarget.block);
1413 static bool CanThrow(Expr *E, ASTContext &Ctx) {
1414 QualType Ty = E->getType();
1415 if (Ty->isFunctionPointerType())
1416 Ty = Ty->getAs<PointerType>()->getPointeeType();
1417 else if (Ty->isBlockPointerType())
1418 Ty = Ty->getAs<BlockPointerType>()->getPointeeType();
1420 const FunctionType *FT = Ty->getAs<FunctionType>();
1422 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT))
1423 if (!isUnresolvedExceptionSpec(Proto->getExceptionSpecType()) &&
1424 Proto->isNothrow(Ctx))
1430 CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) {
1431 // Compute the callee type.
1432 QualType calleeType = C->getCallee()->getType();
1433 if (calleeType == Context->BoundMemberTy) {
1434 QualType boundType = Expr::findBoundMemberType(C->getCallee());
1436 // We should only get a null bound type if processing a dependent
1437 // CFG. Recover by assuming nothing.
1438 if (!boundType.isNull()) calleeType = boundType;
1441 // If this is a call to a no-return function, this stops the block here.
1442 bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn();
1444 bool AddEHEdge = false;
1446 // Languages without exceptions are assumed to not throw.
1447 if (Context->getLangOpts().Exceptions) {
1448 if (BuildOpts.AddEHEdges)
1452 if (FunctionDecl *FD = C->getDirectCallee()) {
1453 if (FD->isNoReturn())
1455 if (FD->hasAttr<NoThrowAttr>())
1459 if (!CanThrow(C->getCallee(), *Context))
1462 if (!NoReturn && !AddEHEdge)
1463 return VisitStmt(C, asc.withAlwaysAdd(true));
1472 Block = createNoReturnBlock();
1474 Block = createBlock();
1476 appendStmt(Block, C);
1479 // Add exceptional edges.
1480 if (TryTerminatedBlock)
1481 addSuccessor(Block, TryTerminatedBlock);
1483 addSuccessor(Block, &cfg->getExit());
1486 return VisitChildren(C);
1489 CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C,
1490 AddStmtChoice asc) {
1491 CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
1492 appendStmt(ConfluenceBlock, C);
1496 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
1497 Succ = ConfluenceBlock;
1499 CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd);
1503 Succ = ConfluenceBlock;
1505 CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd);
1509 Block = createBlock(false);
1510 // See if this is a known constant.
1511 const TryResult& KnownVal = tryEvaluateBool(C->getCond());
1512 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock);
1513 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock);
1514 Block->setTerminator(C);
1515 return addStmt(C->getCond());
1519 CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) {
1520 addLocalScopeAndDtors(C);
1521 CFGBlock *LastBlock = Block;
1523 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend();
1525 // If we hit a segment of code just containing ';' (NullStmts), we can
1526 // get a null block back. In such cases, just use the LastBlock
1527 if (CFGBlock *newBlock = addStmt(*I))
1528 LastBlock = newBlock;
1537 CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C,
1538 AddStmtChoice asc) {
1539 const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C);
1540 const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : NULL);
1542 // Create the confluence block that will "merge" the results of the ternary
1544 CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
1545 appendStmt(ConfluenceBlock, C);
1549 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
1551 // Create a block for the LHS expression if there is an LHS expression. A
1552 // GCC extension allows LHS to be NULL, causing the condition to be the
1553 // value that is returned instead.
1554 // e.g: x ?: y is shorthand for: x ? x : y;
1555 Succ = ConfluenceBlock;
1557 CFGBlock *LHSBlock = 0;
1558 const Expr *trueExpr = C->getTrueExpr();
1559 if (trueExpr != opaqueValue) {
1560 LHSBlock = Visit(C->getTrueExpr(), alwaysAdd);
1566 LHSBlock = ConfluenceBlock;
1568 // Create the block for the RHS expression.
1569 Succ = ConfluenceBlock;
1570 CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd);
1574 // If the condition is a logical '&&' or '||', build a more accurate CFG.
1575 if (BinaryOperator *Cond =
1576 dyn_cast<BinaryOperator>(C->getCond()->IgnoreParens()))
1577 if (Cond->isLogicalOp())
1578 return VisitLogicalOperator(Cond, C, LHSBlock, RHSBlock).first;
1580 // Create the block that will contain the condition.
1581 Block = createBlock(false);
1583 // See if this is a known constant.
1584 const TryResult& KnownVal = tryEvaluateBool(C->getCond());
1585 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock);
1586 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock);
1587 Block->setTerminator(C);
1588 Expr *condExpr = C->getCond();
1591 // Run the condition expression if it's not trivially expressed in
1592 // terms of the opaque value (or if there is no opaque value).
1593 if (condExpr != opaqueValue)
1596 // Before that, run the common subexpression if there was one.
1597 // At least one of this or the above will be run.
1598 return addStmt(BCO->getCommon());
1601 return addStmt(condExpr);
1604 CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) {
1605 // Check if the Decl is for an __label__. If so, elide it from the
1607 if (isa<LabelDecl>(*DS->decl_begin()))
1610 // This case also handles static_asserts.
1611 if (DS->isSingleDecl())
1612 return VisitDeclSubExpr(DS);
1616 // Build an individual DeclStmt for each decl.
1617 for (DeclStmt::reverse_decl_iterator I = DS->decl_rbegin(),
1618 E = DS->decl_rend();
1620 // Get the alignment of the new DeclStmt, padding out to >=8 bytes.
1621 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8
1622 ? 8 : llvm::AlignOf<DeclStmt>::Alignment;
1624 // Allocate the DeclStmt using the BumpPtrAllocator. It will get
1625 // automatically freed with the CFG.
1626 DeclGroupRef DG(*I);
1628 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A);
1629 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D));
1631 // Append the fake DeclStmt to block.
1632 B = VisitDeclSubExpr(DSNew);
1638 /// VisitDeclSubExpr - Utility method to add block-level expressions for
1639 /// DeclStmts and initializers in them.
1640 CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) {
1641 assert(DS->isSingleDecl() && "Can handle single declarations only.");
1642 Decl *D = DS->getSingleDecl();
1644 if (isa<StaticAssertDecl>(D)) {
1645 // static_asserts aren't added to the CFG because they do not impact
1646 // runtime semantics.
1650 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl());
1654 appendStmt(Block, DS);
1658 bool IsReference = false;
1659 bool HasTemporaries = false;
1661 // Guard static initializers under a branch.
1662 CFGBlock *blockAfterStaticInit = 0;
1664 if (BuildOpts.AddStaticInitBranches && VD->isStaticLocal()) {
1665 // For static variables, we need to create a branch to track
1666 // whether or not they are initialized.
1673 blockAfterStaticInit = Succ;
1676 // Destructors of temporaries in initialization expression should be called
1677 // after initialization finishes.
1678 Expr *Init = VD->getInit();
1680 IsReference = VD->getType()->isReferenceType();
1681 HasTemporaries = isa<ExprWithCleanups>(Init);
1683 if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
1684 // Generate destructors for temporaries in initialization expression.
1685 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
1691 appendStmt(Block, DS);
1693 // Keep track of the last non-null block, as 'Block' can be nulled out
1694 // if the initializer expression is something like a 'while' in a
1695 // statement-expression.
1696 CFGBlock *LastBlock = Block;
1699 if (HasTemporaries) {
1700 // For expression with temporaries go directly to subexpression to omit
1701 // generating destructors for the second time.
1702 ExprWithCleanups *EC = cast<ExprWithCleanups>(Init);
1703 if (CFGBlock *newBlock = Visit(EC->getSubExpr()))
1704 LastBlock = newBlock;
1707 if (CFGBlock *newBlock = Visit(Init))
1708 LastBlock = newBlock;
1712 // If the type of VD is a VLA, then we must process its size expressions.
1713 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr());
1714 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) {
1715 if (CFGBlock *newBlock = addStmt(VA->getSizeExpr()))
1716 LastBlock = newBlock;
1719 // Remove variable from local scope.
1720 if (ScopePos && VD == *ScopePos)
1723 CFGBlock *B = LastBlock;
1724 if (blockAfterStaticInit) {
1726 Block = createBlock(false);
1727 Block->setTerminator(DS);
1728 addSuccessor(Block, blockAfterStaticInit);
1729 addSuccessor(Block, B);
1736 CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) {
1737 // We may see an if statement in the middle of a basic block, or it may be the
1738 // first statement we are processing. In either case, we create a new basic
1739 // block. First, we create the blocks for the then...else statements, and
1740 // then we create the block containing the if statement. If we were in the
1741 // middle of a block, we stop processing that block. That block is then the
1742 // implicit successor for the "then" and "else" clauses.
1744 // Save local scope position because in case of condition variable ScopePos
1745 // won't be restored when traversing AST.
1746 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
1748 // Create local scope for possible condition variable.
1749 // Store scope position. Add implicit destructor.
1750 if (VarDecl *VD = I->getConditionVariable()) {
1751 LocalScope::const_iterator BeginScopePos = ScopePos;
1752 addLocalScopeForVarDecl(VD);
1753 addAutomaticObjDtors(ScopePos, BeginScopePos, I);
1756 // The block we were processing is now finished. Make it the successor
1764 // Process the false branch.
1765 CFGBlock *ElseBlock = Succ;
1767 if (Stmt *Else = I->getElse()) {
1768 SaveAndRestore<CFGBlock*> sv(Succ);
1770 // NULL out Block so that the recursive call to Visit will
1771 // create a new basic block.
1774 // If branch is not a compound statement create implicit scope
1775 // and add destructors.
1776 if (!isa<CompoundStmt>(Else))
1777 addLocalScopeAndDtors(Else);
1779 ElseBlock = addStmt(Else);
1781 if (!ElseBlock) // Can occur when the Else body has all NullStmts.
1782 ElseBlock = sv.get();
1789 // Process the true branch.
1790 CFGBlock *ThenBlock;
1792 Stmt *Then = I->getThen();
1794 SaveAndRestore<CFGBlock*> sv(Succ);
1797 // If branch is not a compound statement create implicit scope
1798 // and add destructors.
1799 if (!isa<CompoundStmt>(Then))
1800 addLocalScopeAndDtors(Then);
1802 ThenBlock = addStmt(Then);
1805 // We can reach here if the "then" body has all NullStmts.
1806 // Create an empty block so we can distinguish between true and false
1807 // branches in path-sensitive analyses.
1808 ThenBlock = createBlock(false);
1809 addSuccessor(ThenBlock, sv.get());
1816 // Specially handle "if (expr1 || ...)" and "if (expr1 && ...)" by
1817 // having these handle the actual control-flow jump. Note that
1818 // if we introduce a condition variable, e.g. "if (int x = exp1 || exp2)"
1819 // we resort to the old control-flow behavior. This special handling
1820 // removes infeasible paths from the control-flow graph by having the
1821 // control-flow transfer of '&&' or '||' go directly into the then/else
1823 if (!I->getConditionVariable())
1824 if (BinaryOperator *Cond =
1825 dyn_cast<BinaryOperator>(I->getCond()->IgnoreParens()))
1826 if (Cond->isLogicalOp())
1827 return VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first;
1829 // Now create a new block containing the if statement.
1830 Block = createBlock(false);
1832 // Set the terminator of the new block to the If statement.
1833 Block->setTerminator(I);
1835 // See if this is a known constant.
1836 const TryResult &KnownVal = tryEvaluateBool(I->getCond());
1838 // Now add the successors.
1839 addSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock);
1840 addSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock);
1842 // Add the condition as the last statement in the new block. This may create
1843 // new blocks as the condition may contain control-flow. Any newly created
1844 // blocks will be pointed to be "Block".
1845 CFGBlock *LastBlock = addStmt(I->getCond());
1847 // Finally, if the IfStmt contains a condition variable, add both the IfStmt
1848 // and the condition variable initialization to the CFG.
1849 if (VarDecl *VD = I->getConditionVariable()) {
1850 if (Expr *Init = VD->getInit()) {
1852 appendStmt(Block, I->getConditionVariableDeclStmt());
1853 LastBlock = addStmt(Init);
1861 CFGBlock *CFGBuilder::VisitReturnStmt(ReturnStmt *R) {
1862 // If we were in the middle of a block we stop processing that block.
1864 // NOTE: If a "return" appears in the middle of a block, this means that the
1865 // code afterwards is DEAD (unreachable). We still keep a basic block
1866 // for that code; a simple "mark-and-sweep" from the entry block will be
1867 // able to report such dead blocks.
1869 // Create the new block.
1870 Block = createBlock(false);
1872 // The Exit block is the only successor.
1873 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R);
1874 addSuccessor(Block, &cfg->getExit());
1876 // Add the return statement to the block. This may create new blocks if R
1877 // contains control-flow (short-circuit operations).
1878 return VisitStmt(R, AddStmtChoice::AlwaysAdd);
1881 CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) {
1882 // Get the block of the labeled statement. Add it to our map.
1883 addStmt(L->getSubStmt());
1884 CFGBlock *LabelBlock = Block;
1886 if (!LabelBlock) // This can happen when the body is empty, i.e.
1887 LabelBlock = createBlock(); // scopes that only contains NullStmts.
1889 assert(LabelMap.find(L->getDecl()) == LabelMap.end() &&
1890 "label already in map");
1891 LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos);
1893 // Labels partition blocks, so this is the end of the basic block we were
1894 // processing (L is the block's label). Because this is label (and we have
1895 // already processed the substatement) there is no extra control-flow to worry
1897 LabelBlock->setLabel(L);
1901 // We set Block to NULL to allow lazy creation of a new block (if necessary);
1904 // This block is now the implicit successor of other blocks.
1910 CFGBlock *CFGBuilder::VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc) {
1911 CFGBlock *LastBlock = VisitNoRecurse(E, asc);
1912 for (LambdaExpr::capture_init_iterator it = E->capture_init_begin(),
1913 et = E->capture_init_end(); it != et; ++it) {
1914 if (Expr *Init = *it) {
1915 CFGBlock *Tmp = Visit(Init);
1923 CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) {
1924 // Goto is a control-flow statement. Thus we stop processing the current
1925 // block and create a new one.
1927 Block = createBlock(false);
1928 Block->setTerminator(G);
1930 // If we already know the mapping to the label block add the successor now.
1931 LabelMapTy::iterator I = LabelMap.find(G->getLabel());
1933 if (I == LabelMap.end())
1934 // We will need to backpatch this block later.
1935 BackpatchBlocks.push_back(JumpSource(Block, ScopePos));
1937 JumpTarget JT = I->second;
1938 addAutomaticObjDtors(ScopePos, JT.scopePosition, G);
1939 addSuccessor(Block, JT.block);
1945 CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) {
1946 CFGBlock *LoopSuccessor = NULL;
1948 // Save local scope position because in case of condition variable ScopePos
1949 // won't be restored when traversing AST.
1950 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
1952 // Create local scope for init statement and possible condition variable.
1953 // Add destructor for init statement and condition variable.
1954 // Store scope position for continue statement.
1955 if (Stmt *Init = F->getInit())
1956 addLocalScopeForStmt(Init);
1957 LocalScope::const_iterator LoopBeginScopePos = ScopePos;
1959 if (VarDecl *VD = F->getConditionVariable())
1960 addLocalScopeForVarDecl(VD);
1961 LocalScope::const_iterator ContinueScopePos = ScopePos;
1963 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F);
1965 // "for" is a control-flow statement. Thus we stop processing the current
1970 LoopSuccessor = Block;
1972 LoopSuccessor = Succ;
1974 // Save the current value for the break targets.
1975 // All breaks should go to the code following the loop.
1976 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
1977 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
1979 CFGBlock *BodyBlock = 0, *TransitionBlock = 0;
1981 // Now create the loop body.
1983 assert(F->getBody());
1985 // Save the current values for Block, Succ, continue and break targets.
1986 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
1987 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
1989 // Create an empty block to represent the transition block for looping back
1990 // to the head of the loop. If we have increment code, it will
1991 // go in this block as well.
1992 Block = Succ = TransitionBlock = createBlock(false);
1993 TransitionBlock->setLoopTarget(F);
1995 if (Stmt *I = F->getInc()) {
1996 // Generate increment code in its own basic block. This is the target of
1997 // continue statements.
2001 // Finish up the increment (or empty) block if it hasn't been already.
2003 assert(Block == Succ);
2009 // The starting block for the loop increment is the block that should
2010 // represent the 'loop target' for looping back to the start of the loop.
2011 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
2012 ContinueJumpTarget.block->setLoopTarget(F);
2014 // Loop body should end with destructor of Condition variable (if any).
2015 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F);
2017 // If body is not a compound statement create implicit scope
2018 // and add destructors.
2019 if (!isa<CompoundStmt>(F->getBody()))
2020 addLocalScopeAndDtors(F->getBody());
2022 // Now populate the body block, and in the process create new blocks as we
2023 // walk the body of the loop.
2024 BodyBlock = addStmt(F->getBody());
2027 // In the case of "for (...;...;...);" we can have a null BodyBlock.
2028 // Use the continue jump target as the proxy for the body.
2029 BodyBlock = ContinueJumpTarget.block;
2035 // Because of short-circuit evaluation, the condition of the loop can span
2036 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
2037 // evaluate the condition.
2038 CFGBlock *EntryConditionBlock = 0, *ExitConditionBlock = 0;
2041 Expr *C = F->getCond();
2043 // Specially handle logical operators, which have a slightly
2044 // more optimal CFG representation.
2045 if (BinaryOperator *Cond =
2046 dyn_cast_or_null<BinaryOperator>(C ? C->IgnoreParens() : 0))
2047 if (Cond->isLogicalOp()) {
2048 llvm::tie(EntryConditionBlock, ExitConditionBlock) =
2049 VisitLogicalOperator(Cond, F, BodyBlock, LoopSuccessor);
2053 // The default case when not handling logical operators.
2054 EntryConditionBlock = ExitConditionBlock = createBlock(false);
2055 ExitConditionBlock->setTerminator(F);
2057 // See if this is a known constant.
2058 TryResult KnownVal(true);
2061 // Now add the actual condition to the condition block.
2062 // Because the condition itself may contain control-flow, new blocks may
2063 // be created. Thus we update "Succ" after adding the condition.
2064 Block = ExitConditionBlock;
2065 EntryConditionBlock = addStmt(C);
2067 // If this block contains a condition variable, add both the condition
2068 // variable and initializer to the CFG.
2069 if (VarDecl *VD = F->getConditionVariable()) {
2070 if (Expr *Init = VD->getInit()) {
2072 appendStmt(Block, F->getConditionVariableDeclStmt());
2073 EntryConditionBlock = addStmt(Init);
2074 assert(Block == EntryConditionBlock);
2078 if (Block && badCFG)
2081 KnownVal = tryEvaluateBool(C);
2084 // Add the loop body entry as a successor to the condition.
2085 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock);
2086 // Link up the condition block with the code that follows the loop. (the
2088 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor);
2092 // Link up the loop-back block to the entry condition block.
2093 addSuccessor(TransitionBlock, EntryConditionBlock);
2095 // The condition block is the implicit successor for any code above the loop.
2096 Succ = EntryConditionBlock;
2098 // If the loop contains initialization, create a new block for those
2099 // statements. This block can also contain statements that precede the loop.
2100 if (Stmt *I = F->getInit()) {
2101 Block = createBlock();
2105 // There is no loop initialization. We are thus basically a while loop.
2106 // NULL out Block to force lazy block construction.
2108 Succ = EntryConditionBlock;
2109 return EntryConditionBlock;
2112 CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) {
2113 if (asc.alwaysAdd(*this, M)) {
2115 appendStmt(Block, M);
2117 return Visit(M->getBase());
2120 CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) {
2121 // Objective-C fast enumeration 'for' statements:
2122 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC
2124 // for ( Type newVariable in collection_expression ) { statements }
2129 // 1. collection_expression
2130 // T. jump to loop_entry
2132 // 1. side-effects of element expression
2133 // 1. ObjCForCollectionStmt [performs binding to newVariable]
2134 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil]
2137 // T. jump to loop_entry
2143 // Type existingItem;
2144 // for ( existingItem in expression ) { statements }
2148 // the same with newVariable replaced with existingItem; the binding works
2149 // the same except that for one ObjCForCollectionStmt::getElement() returns
2150 // a DeclStmt and the other returns a DeclRefExpr.
2153 CFGBlock *LoopSuccessor = 0;
2158 LoopSuccessor = Block;
2161 LoopSuccessor = Succ;
2163 // Build the condition blocks.
2164 CFGBlock *ExitConditionBlock = createBlock(false);
2166 // Set the terminator for the "exit" condition block.
2167 ExitConditionBlock->setTerminator(S);
2169 // The last statement in the block should be the ObjCForCollectionStmt, which
2170 // performs the actual binding to 'element' and determines if there are any
2171 // more items in the collection.
2172 appendStmt(ExitConditionBlock, S);
2173 Block = ExitConditionBlock;
2175 // Walk the 'element' expression to see if there are any side-effects. We
2176 // generate new blocks as necessary. We DON'T add the statement by default to
2177 // the CFG unless it contains control-flow.
2178 CFGBlock *EntryConditionBlock = Visit(S->getElement(),
2179 AddStmtChoice::NotAlwaysAdd);
2186 // The condition block is the implicit successor for the loop body as well as
2187 // any code above the loop.
2188 Succ = EntryConditionBlock;
2190 // Now create the true branch.
2192 // Save the current values for Succ, continue and break targets.
2193 SaveAndRestore<CFGBlock*> save_Succ(Succ);
2194 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
2195 save_break(BreakJumpTarget);
2197 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
2198 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos);
2200 CFGBlock *BodyBlock = addStmt(S->getBody());
2203 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;"
2209 // This new body block is a successor to our "exit" condition block.
2210 addSuccessor(ExitConditionBlock, BodyBlock);
2213 // Link up the condition block with the code that follows the loop.
2214 // (the false branch).
2215 addSuccessor(ExitConditionBlock, LoopSuccessor);
2217 // Now create a prologue block to contain the collection expression.
2218 Block = createBlock();
2219 return addStmt(S->getCollection());
2222 CFGBlock *CFGBuilder::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) {
2224 return addStmt(S->getSubStmt());
2225 // TODO: consider adding cleanups for the end of @autoreleasepool scope.
2228 CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) {
2229 // FIXME: Add locking 'primitives' to CFG for @synchronized.
2232 CFGBlock *SyncBlock = addStmt(S->getSynchBody());
2234 // The sync body starts its own basic block. This makes it a little easier
2235 // for diagnostic clients.
2244 // Add the @synchronized to the CFG.
2246 appendStmt(Block, S);
2248 // Inline the sync expression.
2249 return addStmt(S->getSynchExpr());
2252 CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) {
2257 CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) {
2260 // Add the PseudoObject as the last thing.
2261 appendStmt(Block, E);
2263 CFGBlock *lastBlock = Block;
2265 // Before that, evaluate all of the semantics in order. In
2266 // CFG-land, that means appending them in reverse order.
2267 for (unsigned i = E->getNumSemanticExprs(); i != 0; ) {
2268 Expr *Semantic = E->getSemanticExpr(--i);
2270 // If the semantic is an opaque value, we're being asked to bind
2271 // it to its source expression.
2272 if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
2273 Semantic = OVE->getSourceExpr();
2275 if (CFGBlock *B = Visit(Semantic))
2282 CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) {
2283 CFGBlock *LoopSuccessor = NULL;
2285 // Save local scope position because in case of condition variable ScopePos
2286 // won't be restored when traversing AST.
2287 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2289 // Create local scope for possible condition variable.
2290 // Store scope position for continue statement.
2291 LocalScope::const_iterator LoopBeginScopePos = ScopePos;
2292 if (VarDecl *VD = W->getConditionVariable()) {
2293 addLocalScopeForVarDecl(VD);
2294 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W);
2297 // "while" is a control-flow statement. Thus we stop processing the current
2302 LoopSuccessor = Block;
2305 LoopSuccessor = Succ;
2308 CFGBlock *BodyBlock = 0, *TransitionBlock = 0;
2310 // Process the loop body.
2312 assert(W->getBody());
2314 // Save the current values for Block, Succ, continue and break targets.
2315 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
2316 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
2317 save_break(BreakJumpTarget);
2319 // Create an empty block to represent the transition block for looping back
2320 // to the head of the loop.
2321 Succ = TransitionBlock = createBlock(false);
2322 TransitionBlock->setLoopTarget(W);
2323 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos);
2325 // All breaks should go to the code following the loop.
2326 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
2328 // Loop body should end with destructor of Condition variable (if any).
2329 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W);
2331 // If body is not a compound statement create implicit scope
2332 // and add destructors.
2333 if (!isa<CompoundStmt>(W->getBody()))
2334 addLocalScopeAndDtors(W->getBody());
2336 // Create the body. The returned block is the entry to the loop body.
2337 BodyBlock = addStmt(W->getBody());
2340 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;"
2341 else if (Block && badCFG)
2345 // Because of short-circuit evaluation, the condition of the loop can span
2346 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
2347 // evaluate the condition.
2348 CFGBlock *EntryConditionBlock = 0, *ExitConditionBlock = 0;
2351 Expr *C = W->getCond();
2353 // Specially handle logical operators, which have a slightly
2354 // more optimal CFG representation.
2355 if (BinaryOperator *Cond = dyn_cast<BinaryOperator>(C->IgnoreParens()))
2356 if (Cond->isLogicalOp()) {
2357 llvm::tie(EntryConditionBlock, ExitConditionBlock) =
2358 VisitLogicalOperator(Cond, W, BodyBlock,
2363 // The default case when not handling logical operators.
2364 ExitConditionBlock = createBlock(false);
2365 ExitConditionBlock->setTerminator(W);
2367 // Now add the actual condition to the condition block.
2368 // Because the condition itself may contain control-flow, new blocks may
2369 // be created. Thus we update "Succ" after adding the condition.
2370 Block = ExitConditionBlock;
2371 Block = EntryConditionBlock = addStmt(C);
2373 // If this block contains a condition variable, add both the condition
2374 // variable and initializer to the CFG.
2375 if (VarDecl *VD = W->getConditionVariable()) {
2376 if (Expr *Init = VD->getInit()) {
2378 appendStmt(Block, W->getConditionVariableDeclStmt());
2379 EntryConditionBlock = addStmt(Init);
2380 assert(Block == EntryConditionBlock);
2384 if (Block && badCFG)
2387 // See if this is a known constant.
2388 const TryResult& KnownVal = tryEvaluateBool(C);
2390 // Add the loop body entry as a successor to the condition.
2391 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock);
2392 // Link up the condition block with the code that follows the loop. (the
2394 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor);
2398 // Link up the loop-back block to the entry condition block.
2399 addSuccessor(TransitionBlock, EntryConditionBlock);
2401 // There can be no more statements in the condition block since we loop back
2402 // to this block. NULL out Block to force lazy creation of another block.
2405 // Return the condition block, which is the dominating block for the loop.
2406 Succ = EntryConditionBlock;
2407 return EntryConditionBlock;
2411 CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) {
2412 // FIXME: For now we pretend that @catch and the code it contains does not
2417 CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) {
2418 // FIXME: This isn't complete. We basically treat @throw like a return
2421 // If we were in the middle of a block we stop processing that block.
2425 // Create the new block.
2426 Block = createBlock(false);
2428 // The Exit block is the only successor.
2429 addSuccessor(Block, &cfg->getExit());
2431 // Add the statement to the block. This may create new blocks if S contains
2432 // control-flow (short-circuit operations).
2433 return VisitStmt(S, AddStmtChoice::AlwaysAdd);
2436 CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) {
2437 // If we were in the middle of a block we stop processing that block.
2441 // Create the new block.
2442 Block = createBlock(false);
2444 if (TryTerminatedBlock)
2445 // The current try statement is the only successor.
2446 addSuccessor(Block, TryTerminatedBlock);
2448 // otherwise the Exit block is the only successor.
2449 addSuccessor(Block, &cfg->getExit());
2451 // Add the statement to the block. This may create new blocks if S contains
2452 // control-flow (short-circuit operations).
2453 return VisitStmt(T, AddStmtChoice::AlwaysAdd);
2456 CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) {
2457 CFGBlock *LoopSuccessor = NULL;
2459 // "do...while" is a control-flow statement. Thus we stop processing the
2464 LoopSuccessor = Block;
2466 LoopSuccessor = Succ;
2468 // Because of short-circuit evaluation, the condition of the loop can span
2469 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
2470 // evaluate the condition.
2471 CFGBlock *ExitConditionBlock = createBlock(false);
2472 CFGBlock *EntryConditionBlock = ExitConditionBlock;
2474 // Set the terminator for the "exit" condition block.
2475 ExitConditionBlock->setTerminator(D);
2477 // Now add the actual condition to the condition block. Because the condition
2478 // itself may contain control-flow, new blocks may be created.
2479 if (Stmt *C = D->getCond()) {
2480 Block = ExitConditionBlock;
2481 EntryConditionBlock = addStmt(C);
2488 // The condition block is the implicit successor for the loop body.
2489 Succ = EntryConditionBlock;
2491 // See if this is a known constant.
2492 const TryResult &KnownVal = tryEvaluateBool(D->getCond());
2494 // Process the loop body.
2495 CFGBlock *BodyBlock = NULL;
2497 assert(D->getBody());
2499 // Save the current values for Block, Succ, and continue and break targets
2500 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
2501 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
2502 save_break(BreakJumpTarget);
2504 // All continues within this loop should go to the condition block
2505 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos);
2507 // All breaks should go to the code following the loop.
2508 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
2510 // NULL out Block to force lazy instantiation of blocks for the body.
2513 // If body is not a compound statement create implicit scope
2514 // and add destructors.
2515 if (!isa<CompoundStmt>(D->getBody()))
2516 addLocalScopeAndDtors(D->getBody());
2518 // Create the body. The returned block is the entry to the loop body.
2519 BodyBlock = addStmt(D->getBody());
2522 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)"
2528 if (!KnownVal.isFalse()) {
2529 // Add an intermediate block between the BodyBlock and the
2530 // ExitConditionBlock to represent the "loop back" transition. Create an
2531 // empty block to represent the transition block for looping back to the
2532 // head of the loop.
2533 // FIXME: Can we do this more efficiently without adding another block?
2536 CFGBlock *LoopBackBlock = createBlock();
2537 LoopBackBlock->setLoopTarget(D);
2539 // Add the loop body entry as a successor to the condition.
2540 addSuccessor(ExitConditionBlock, LoopBackBlock);
2543 addSuccessor(ExitConditionBlock, NULL);
2546 // Link up the condition block with the code that follows the loop.
2547 // (the false branch).
2548 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor);
2550 // There can be no more statements in the body block(s) since we loop back to
2551 // the body. NULL out Block to force lazy creation of another block.
2554 // Return the loop body, which is the dominating block for the loop.
2559 CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) {
2560 // "continue" is a control-flow statement. Thus we stop processing the
2565 // Now create a new block that ends with the continue statement.
2566 Block = createBlock(false);
2567 Block->setTerminator(C);
2569 // If there is no target for the continue, then we are looking at an
2570 // incomplete AST. This means the CFG cannot be constructed.
2571 if (ContinueJumpTarget.block) {
2572 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C);
2573 addSuccessor(Block, ContinueJumpTarget.block);
2580 CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
2581 AddStmtChoice asc) {
2583 if (asc.alwaysAdd(*this, E)) {
2585 appendStmt(Block, E);
2588 // VLA types have expressions that must be evaluated.
2589 CFGBlock *lastBlock = Block;
2591 if (E->isArgumentType()) {
2592 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr());
2593 VA != 0; VA = FindVA(VA->getElementType().getTypePtr()))
2594 lastBlock = addStmt(VA->getSizeExpr());
2599 /// VisitStmtExpr - Utility method to handle (nested) statement
2600 /// expressions (a GCC extension).
2601 CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) {
2602 if (asc.alwaysAdd(*this, SE)) {
2604 appendStmt(Block, SE);
2606 return VisitCompoundStmt(SE->getSubStmt());
2609 CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) {
2610 // "switch" is a control-flow statement. Thus we stop processing the current
2612 CFGBlock *SwitchSuccessor = NULL;
2614 // Save local scope position because in case of condition variable ScopePos
2615 // won't be restored when traversing AST.
2616 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2618 // Create local scope for possible condition variable.
2619 // Store scope position. Add implicit destructor.
2620 if (VarDecl *VD = Terminator->getConditionVariable()) {
2621 LocalScope::const_iterator SwitchBeginScopePos = ScopePos;
2622 addLocalScopeForVarDecl(VD);
2623 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator);
2629 SwitchSuccessor = Block;
2630 } else SwitchSuccessor = Succ;
2632 // Save the current "switch" context.
2633 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock),
2634 save_default(DefaultCaseBlock);
2635 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
2637 // Set the "default" case to be the block after the switch statement. If the
2638 // switch statement contains a "default:", this value will be overwritten with
2639 // the block for that code.
2640 DefaultCaseBlock = SwitchSuccessor;
2642 // Create a new block that will contain the switch statement.
2643 SwitchTerminatedBlock = createBlock(false);
2645 // Now process the switch body. The code after the switch is the implicit
2647 Succ = SwitchSuccessor;
2648 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos);
2650 // When visiting the body, the case statements should automatically get linked
2651 // up to the switch. We also don't keep a pointer to the body, since all
2652 // control-flow from the switch goes to case/default statements.
2653 assert(Terminator->getBody() && "switch must contain a non-NULL body");
2656 // For pruning unreachable case statements, save the current state
2657 // for tracking the condition value.
2658 SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered,
2661 // Determine if the switch condition can be explicitly evaluated.
2662 assert(Terminator->getCond() && "switch condition must be non-NULL");
2663 Expr::EvalResult result;
2664 bool b = tryEvaluate(Terminator->getCond(), result);
2665 SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond,
2668 // If body is not a compound statement create implicit scope
2669 // and add destructors.
2670 if (!isa<CompoundStmt>(Terminator->getBody()))
2671 addLocalScopeAndDtors(Terminator->getBody());
2673 addStmt(Terminator->getBody());
2679 // If we have no "default:" case, the default transition is to the code
2680 // following the switch body. Moreover, take into account if all the
2681 // cases of a switch are covered (e.g., switching on an enum value).
2682 addSuccessor(SwitchTerminatedBlock,
2683 switchExclusivelyCovered || Terminator->isAllEnumCasesCovered()
2684 ? 0 : DefaultCaseBlock);
2686 // Add the terminator and condition in the switch block.
2687 SwitchTerminatedBlock->setTerminator(Terminator);
2688 Block = SwitchTerminatedBlock;
2689 CFGBlock *LastBlock = addStmt(Terminator->getCond());
2691 // Finally, if the SwitchStmt contains a condition variable, add both the
2692 // SwitchStmt and the condition variable initialization to the CFG.
2693 if (VarDecl *VD = Terminator->getConditionVariable()) {
2694 if (Expr *Init = VD->getInit()) {
2696 appendStmt(Block, Terminator->getConditionVariableDeclStmt());
2697 LastBlock = addStmt(Init);
2704 static bool shouldAddCase(bool &switchExclusivelyCovered,
2705 const Expr::EvalResult *switchCond,
2711 bool addCase = false;
2713 if (!switchExclusivelyCovered) {
2714 if (switchCond->Val.isInt()) {
2715 // Evaluate the LHS of the case value.
2716 const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx);
2717 const llvm::APSInt &condInt = switchCond->Val.getInt();
2719 if (condInt == lhsInt) {
2721 switchExclusivelyCovered = true;
2723 else if (condInt < lhsInt) {
2724 if (const Expr *RHS = CS->getRHS()) {
2725 // Evaluate the RHS of the case value.
2726 const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx);
2727 if (V2 <= condInt) {
2729 switchExclusivelyCovered = true;
2740 CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) {
2741 // CaseStmts are essentially labels, so they are the first statement in a
2743 CFGBlock *TopBlock = 0, *LastBlock = 0;
2745 if (Stmt *Sub = CS->getSubStmt()) {
2746 // For deeply nested chains of CaseStmts, instead of doing a recursion
2747 // (which can blow out the stack), manually unroll and create blocks
2749 while (isa<CaseStmt>(Sub)) {
2750 CFGBlock *currentBlock = createBlock(false);
2751 currentBlock->setLabel(CS);
2754 addSuccessor(LastBlock, currentBlock);
2756 TopBlock = currentBlock;
2758 addSuccessor(SwitchTerminatedBlock,
2759 shouldAddCase(switchExclusivelyCovered, switchCond,
2761 ? currentBlock : 0);
2763 LastBlock = currentBlock;
2764 CS = cast<CaseStmt>(Sub);
2765 Sub = CS->getSubStmt();
2771 CFGBlock *CaseBlock = Block;
2773 CaseBlock = createBlock();
2775 // Cases statements partition blocks, so this is the top of the basic block we
2776 // were processing (the "case XXX:" is the label).
2777 CaseBlock->setLabel(CS);
2782 // Add this block to the list of successors for the block with the switch
2784 assert(SwitchTerminatedBlock);
2785 addSuccessor(SwitchTerminatedBlock,
2786 shouldAddCase(switchExclusivelyCovered, switchCond,
2790 // We set Block to NULL to allow lazy creation of a new block (if necessary)
2794 addSuccessor(LastBlock, CaseBlock);
2797 // This block is now the implicit successor of other blocks.
2804 CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) {
2805 if (Terminator->getSubStmt())
2806 addStmt(Terminator->getSubStmt());
2808 DefaultCaseBlock = Block;
2810 if (!DefaultCaseBlock)
2811 DefaultCaseBlock = createBlock();
2813 // Default statements partition blocks, so this is the top of the basic block
2814 // we were processing (the "default:" is the label).
2815 DefaultCaseBlock->setLabel(Terminator);
2820 // Unlike case statements, we don't add the default block to the successors
2821 // for the switch statement immediately. This is done when we finish
2822 // processing the switch statement. This allows for the default case
2823 // (including a fall-through to the code after the switch statement) to always
2824 // be the last successor of a switch-terminated block.
2826 // We set Block to NULL to allow lazy creation of a new block (if necessary)
2829 // This block is now the implicit successor of other blocks.
2830 Succ = DefaultCaseBlock;
2832 return DefaultCaseBlock;
2835 CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) {
2836 // "try"/"catch" is a control-flow statement. Thus we stop processing the
2838 CFGBlock *TrySuccessor = NULL;
2843 TrySuccessor = Block;
2844 } else TrySuccessor = Succ;
2846 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock;
2848 // Create a new block that will contain the try statement.
2849 CFGBlock *NewTryTerminatedBlock = createBlock(false);
2850 // Add the terminator in the try block.
2851 NewTryTerminatedBlock->setTerminator(Terminator);
2853 bool HasCatchAll = false;
2854 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) {
2855 // The code after the try is the implicit successor.
2856 Succ = TrySuccessor;
2857 CXXCatchStmt *CS = Terminator->getHandler(h);
2858 if (CS->getExceptionDecl() == 0) {
2862 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS);
2863 if (CatchBlock == 0)
2865 // Add this block to the list of successors for the block with the try
2867 addSuccessor(NewTryTerminatedBlock, CatchBlock);
2870 if (PrevTryTerminatedBlock)
2871 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock);
2873 addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
2876 // The code after the try is the implicit successor.
2877 Succ = TrySuccessor;
2879 // Save the current "try" context.
2880 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock);
2881 cfg->addTryDispatchBlock(TryTerminatedBlock);
2883 assert(Terminator->getTryBlock() && "try must contain a non-NULL body");
2885 return addStmt(Terminator->getTryBlock());
2888 CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) {
2889 // CXXCatchStmt are treated like labels, so they are the first statement in a
2892 // Save local scope position because in case of exception variable ScopePos
2893 // won't be restored when traversing AST.
2894 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2896 // Create local scope for possible exception variable.
2897 // Store scope position. Add implicit destructor.
2898 if (VarDecl *VD = CS->getExceptionDecl()) {
2899 LocalScope::const_iterator BeginScopePos = ScopePos;
2900 addLocalScopeForVarDecl(VD);
2901 addAutomaticObjDtors(ScopePos, BeginScopePos, CS);
2904 if (CS->getHandlerBlock())
2905 addStmt(CS->getHandlerBlock());
2907 CFGBlock *CatchBlock = Block;
2909 CatchBlock = createBlock();
2911 // CXXCatchStmt is more than just a label. They have semantic meaning
2912 // as well, as they implicitly "initialize" the catch variable. Add
2913 // it to the CFG as a CFGElement so that the control-flow of these
2914 // semantics gets captured.
2915 appendStmt(CatchBlock, CS);
2917 // Also add the CXXCatchStmt as a label, to mirror handling of regular
2919 CatchBlock->setLabel(CS);
2921 // Bail out if the CFG is bad.
2925 // We set Block to NULL to allow lazy creation of a new block (if necessary)
2931 CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) {
2932 // C++0x for-range statements are specified as [stmt.ranged]:
2935 // auto && __range = range-init;
2936 // for ( auto __begin = begin-expr,
2937 // __end = end-expr;
2938 // __begin != __end;
2940 // for-range-declaration = *__begin;
2945 // Save local scope position before the addition of the implicit variables.
2946 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2948 // Create local scopes and destructors for range, begin and end variables.
2949 if (Stmt *Range = S->getRangeStmt())
2950 addLocalScopeForStmt(Range);
2951 if (Stmt *BeginEnd = S->getBeginEndStmt())
2952 addLocalScopeForStmt(BeginEnd);
2953 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), S);
2955 LocalScope::const_iterator ContinueScopePos = ScopePos;
2957 // "for" is a control-flow statement. Thus we stop processing the current
2959 CFGBlock *LoopSuccessor = NULL;
2963 LoopSuccessor = Block;
2965 LoopSuccessor = Succ;
2967 // Save the current value for the break targets.
2968 // All breaks should go to the code following the loop.
2969 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
2970 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
2972 // The block for the __begin != __end expression.
2973 CFGBlock *ConditionBlock = createBlock(false);
2974 ConditionBlock->setTerminator(S);
2976 // Now add the actual condition to the condition block.
2977 if (Expr *C = S->getCond()) {
2978 Block = ConditionBlock;
2979 CFGBlock *BeginConditionBlock = addStmt(C);
2982 assert(BeginConditionBlock == ConditionBlock &&
2983 "condition block in for-range was unexpectedly complex");
2984 (void)BeginConditionBlock;
2987 // The condition block is the implicit successor for the loop body as well as
2988 // any code above the loop.
2989 Succ = ConditionBlock;
2991 // See if this is a known constant.
2992 TryResult KnownVal(true);
2995 KnownVal = tryEvaluateBool(S->getCond());
2997 // Now create the loop body.
2999 assert(S->getBody());
3001 // Save the current values for Block, Succ, and continue targets.
3002 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
3003 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
3005 // Generate increment code in its own basic block. This is the target of
3006 // continue statements.
3008 Succ = addStmt(S->getInc());
3009 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
3011 // The starting block for the loop increment is the block that should
3012 // represent the 'loop target' for looping back to the start of the loop.
3013 ContinueJumpTarget.block->setLoopTarget(S);
3015 // Finish up the increment block and prepare to start the loop body.
3022 // Add implicit scope and dtors for loop variable.
3023 addLocalScopeAndDtors(S->getLoopVarStmt());
3025 // Populate a new block to contain the loop body and loop variable.
3026 addStmt(S->getBody());
3029 CFGBlock *LoopVarStmtBlock = addStmt(S->getLoopVarStmt());
3033 // This new body block is a successor to our condition block.
3034 addSuccessor(ConditionBlock, KnownVal.isFalse() ? 0 : LoopVarStmtBlock);
3037 // Link up the condition block with the code that follows the loop (the
3039 addSuccessor(ConditionBlock, KnownVal.isTrue() ? 0 : LoopSuccessor);
3041 // Add the initialization statements.
3042 Block = createBlock();
3043 addStmt(S->getBeginEndStmt());
3044 return addStmt(S->getRangeStmt());
3047 CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E,
3048 AddStmtChoice asc) {
3049 if (BuildOpts.AddTemporaryDtors) {
3050 // If adding implicit destructors visit the full expression for adding
3051 // destructors of temporaries.
3052 VisitForTemporaryDtors(E->getSubExpr());
3054 // Full expression has to be added as CFGStmt so it will be sequenced
3055 // before destructors of it's temporaries.
3056 asc = asc.withAlwaysAdd(true);
3058 return Visit(E->getSubExpr(), asc);
3061 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
3062 AddStmtChoice asc) {
3063 if (asc.alwaysAdd(*this, E)) {
3065 appendStmt(Block, E);
3067 // We do not want to propagate the AlwaysAdd property.
3068 asc = asc.withAlwaysAdd(false);
3070 return Visit(E->getSubExpr(), asc);
3073 CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C,
3074 AddStmtChoice asc) {
3076 appendStmt(Block, C);
3078 return VisitChildren(C);
3081 CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
3082 AddStmtChoice asc) {
3083 if (asc.alwaysAdd(*this, E)) {
3085 appendStmt(Block, E);
3086 // We do not want to propagate the AlwaysAdd property.
3087 asc = asc.withAlwaysAdd(false);
3089 return Visit(E->getSubExpr(), asc);
3092 CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
3093 AddStmtChoice asc) {
3095 appendStmt(Block, C);
3096 return VisitChildren(C);
3099 CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E,
3100 AddStmtChoice asc) {
3101 if (asc.alwaysAdd(*this, E)) {
3103 appendStmt(Block, E);
3105 return Visit(E->getSubExpr(), AddStmtChoice());
3108 CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) {
3109 // Lazily create the indirect-goto dispatch block if there isn't one already.
3110 CFGBlock *IBlock = cfg->getIndirectGotoBlock();
3113 IBlock = createBlock(false);
3114 cfg->setIndirectGotoBlock(IBlock);
3117 // IndirectGoto is a control-flow statement. Thus we stop processing the
3118 // current block and create a new one.
3122 Block = createBlock(false);
3123 Block->setTerminator(I);
3124 addSuccessor(Block, IBlock);
3125 return addStmt(I->getTarget());
3128 CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) {
3129 assert(BuildOpts.AddImplicitDtors && BuildOpts.AddTemporaryDtors);
3136 switch (E->getStmtClass()) {
3138 return VisitChildrenForTemporaryDtors(E);
3140 case Stmt::BinaryOperatorClass:
3141 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E));
3143 case Stmt::CXXBindTemporaryExprClass:
3144 return VisitCXXBindTemporaryExprForTemporaryDtors(
3145 cast<CXXBindTemporaryExpr>(E), BindToTemporary);
3147 case Stmt::BinaryConditionalOperatorClass:
3148 case Stmt::ConditionalOperatorClass:
3149 return VisitConditionalOperatorForTemporaryDtors(
3150 cast<AbstractConditionalOperator>(E), BindToTemporary);
3152 case Stmt::ImplicitCastExprClass:
3153 // For implicit cast we want BindToTemporary to be passed further.
3154 E = cast<CastExpr>(E)->getSubExpr();
3157 case Stmt::ParenExprClass:
3158 E = cast<ParenExpr>(E)->getSubExpr();
3161 case Stmt::MaterializeTemporaryExprClass:
3162 E = cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr();
3167 CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) {
3168 // When visiting children for destructors we want to visit them in reverse
3169 // order that they will appear in the CFG. Because the CFG is built
3170 // bottom-up, this means we visit them in their natural order, which
3171 // reverses them in the CFG.
3172 CFGBlock *B = Block;
3173 for (Stmt::child_range I = E->children(); I; ++I) {
3174 if (Stmt *Child = *I)
3175 if (CFGBlock *R = VisitForTemporaryDtors(Child))
3181 CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) {
3182 if (E->isLogicalOp()) {
3183 // Destructors for temporaries in LHS expression should be called after
3184 // those for RHS expression. Even if this will unnecessarily create a block,
3185 // this block will be used at least by the full expression.
3187 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS());
3191 Succ = ConfluenceBlock;
3193 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS());
3199 // If RHS expression did produce destructors we need to connect created
3200 // blocks to CFG in same manner as for binary operator itself.
3201 CFGBlock *LHSBlock = createBlock(false);
3202 LHSBlock->setTerminator(CFGTerminator(E, true));
3204 // For binary operator LHS block is before RHS in list of predecessors
3205 // of ConfluenceBlock.
3206 std::reverse(ConfluenceBlock->pred_begin(),
3207 ConfluenceBlock->pred_end());
3209 // See if this is a known constant.
3210 TryResult KnownVal = tryEvaluateBool(E->getLHS());
3211 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr))
3214 // Link LHSBlock with RHSBlock exactly the same way as for binary operator
3216 if (E->getOpcode() == BO_LOr) {
3217 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock);
3218 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock);
3220 assert (E->getOpcode() == BO_LAnd);
3221 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock);
3222 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock);
3229 Block = ConfluenceBlock;
3230 return ConfluenceBlock;
3233 if (E->isAssignmentOp()) {
3234 // For assignment operator (=) LHS expression is visited
3235 // before RHS expression. For destructors visit them in reverse order.
3236 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS());
3237 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS());
3238 return LHSBlock ? LHSBlock : RHSBlock;
3241 // For any other binary operator RHS expression is visited before
3242 // LHS expression (order of children). For destructors visit them in reverse
3244 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS());
3245 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS());
3246 return RHSBlock ? RHSBlock : LHSBlock;
3249 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors(
3250 CXXBindTemporaryExpr *E, bool BindToTemporary) {
3251 // First add destructors for temporaries in subexpression.
3252 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr());
3253 if (!BindToTemporary) {
3254 // If lifetime of temporary is not prolonged (by assigning to constant
3255 // reference) add destructor for it.
3257 // If the destructor is marked as a no-return destructor, we need to create
3258 // a new block for the destructor which does not have as a successor
3259 // anything built thus far. Control won't flow out of this block.
3260 const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor();
3261 if (Dtor->isNoReturn())
3262 Block = createNoReturnBlock();
3266 appendTemporaryDtor(Block, E);
3272 CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors(
3273 AbstractConditionalOperator *E, bool BindToTemporary) {
3274 // First add destructors for condition expression. Even if this will
3275 // unnecessarily create a block, this block will be used at least by the full
3278 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond());
3281 if (BinaryConditionalOperator *BCO
3282 = dyn_cast<BinaryConditionalOperator>(E)) {
3283 ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon());
3288 // Try to add block with destructors for LHS expression.
3289 CFGBlock *LHSBlock = NULL;
3290 Succ = ConfluenceBlock;
3292 LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary);
3296 // Try to add block with destructors for RHS expression;
3297 Succ = ConfluenceBlock;
3299 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(),
3304 if (!RHSBlock && !LHSBlock) {
3305 // If neither LHS nor RHS expression had temporaries to destroy don't create
3307 Block = ConfluenceBlock;
3311 Block = createBlock(false);
3312 Block->setTerminator(CFGTerminator(E, true));
3314 // See if this is a known constant.
3315 const TryResult &KnownVal = tryEvaluateBool(E->getCond());
3318 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock);
3319 } else if (KnownVal.isFalse()) {
3320 addSuccessor(Block, NULL);
3322 addSuccessor(Block, ConfluenceBlock);
3323 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end());
3327 RHSBlock = ConfluenceBlock;
3328 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock);
3333 } // end anonymous namespace
3335 /// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has
3336 /// no successors or predecessors. If this is the first block created in the
3337 /// CFG, it is automatically set to be the Entry and Exit of the CFG.
3338 CFGBlock *CFG::createBlock() {
3339 bool first_block = begin() == end();
3341 // Create the block.
3342 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>();
3343 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this);
3344 Blocks.push_back(Mem, BlkBVC);
3346 // If this is the first block, set it as the Entry and Exit.
3348 Entry = Exit = &back();
3350 // Return the block.
3354 /// buildCFG - Constructs a CFG from an AST. Ownership of the returned
3355 /// CFG is returned to the caller.
3356 CFG* CFG::buildCFG(const Decl *D, Stmt *Statement, ASTContext *C,
3357 const BuildOptions &BO) {
3358 CFGBuilder Builder(C, BO);
3359 return Builder.buildCFG(D, Statement);
3362 const CXXDestructorDecl *
3363 CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const {
3364 switch (getKind()) {
3365 case CFGElement::Statement:
3366 case CFGElement::Initializer:
3367 llvm_unreachable("getDestructorDecl should only be used with "
3369 case CFGElement::AutomaticObjectDtor: {
3370 const VarDecl *var = castAs<CFGAutomaticObjDtor>().getVarDecl();
3371 QualType ty = var->getType();
3372 ty = ty.getNonReferenceType();
3373 while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) {
3374 ty = arrayType->getElementType();
3376 const RecordType *recordType = ty->getAs<RecordType>();
3377 const CXXRecordDecl *classDecl =
3378 cast<CXXRecordDecl>(recordType->getDecl());
3379 return classDecl->getDestructor();
3381 case CFGElement::TemporaryDtor: {
3382 const CXXBindTemporaryExpr *bindExpr =
3383 castAs<CFGTemporaryDtor>().getBindTemporaryExpr();
3384 const CXXTemporary *temp = bindExpr->getTemporary();
3385 return temp->getDestructor();
3387 case CFGElement::BaseDtor:
3388 case CFGElement::MemberDtor:
3390 // Not yet supported.
3393 llvm_unreachable("getKind() returned bogus value");
3396 bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const {
3397 if (const CXXDestructorDecl *DD = getDestructorDecl(astContext))
3398 return DD->isNoReturn();
3402 //===----------------------------------------------------------------------===//
3403 // CFG: Queries for BlkExprs.
3404 //===----------------------------------------------------------------------===//
3407 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy;
3410 static void FindSubExprAssignments(const Stmt *S,
3411 llvm::SmallPtrSet<const Expr*,50>& Set) {
3415 for (Stmt::const_child_range I = S->children(); I; ++I) {
3416 const Stmt *child = *I;
3420 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(child))
3421 if (B->isAssignmentOp()) Set.insert(B);
3423 FindSubExprAssignments(child, Set);
3427 static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) {
3428 BlkExprMapTy* M = new BlkExprMapTy();
3430 // Look for assignments that are used as subexpressions. These are the only
3431 // assignments that we want to *possibly* register as a block-level
3432 // expression. Basically, if an assignment occurs both in a subexpression and
3433 // at the block-level, it is a block-level expression.
3434 llvm::SmallPtrSet<const Expr*,50> SubExprAssignments;
3436 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I)
3437 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI)
3438 if (Optional<CFGStmt> S = BI->getAs<CFGStmt>())
3439 FindSubExprAssignments(S->getStmt(), SubExprAssignments);
3441 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) {
3443 // Iterate over the statements again on identify the Expr* and Stmt* at the
3444 // block-level that are block-level expressions.
3446 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) {
3447 Optional<CFGStmt> CS = BI->getAs<CFGStmt>();
3450 if (const Expr *Exp = dyn_cast<Expr>(CS->getStmt())) {
3451 assert((Exp->IgnoreParens() == Exp) && "No parens on block-level exps");
3453 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) {
3454 // Assignment expressions that are not nested within another
3455 // expression are really "statements" whose value is never used by
3456 // another expression.
3457 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp))
3459 } else if (const StmtExpr *SE = dyn_cast<StmtExpr>(Exp)) {
3460 // Special handling for statement expressions. The last statement in
3461 // the statement expression is also a block-level expr.
3462 const CompoundStmt *C = SE->getSubStmt();
3463 if (!C->body_empty()) {
3464 const Stmt *Last = C->body_back();
3465 if (const Expr *LastEx = dyn_cast<Expr>(Last))
3466 Last = LastEx->IgnoreParens();
3467 unsigned x = M->size();
3472 unsigned x = M->size();
3477 // Look at terminators. The condition is a block-level expression.
3479 Stmt *S = (*I)->getTerminatorCondition();
3481 if (S && M->find(S) == M->end()) {
3482 unsigned x = M->size();
3490 CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt *S) {
3492 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); }
3494 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap);
3495 BlkExprMapTy::iterator I = M->find(S);
3496 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second);
3499 unsigned CFG::getNumBlkExprs() {
3500 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap))
3503 // We assume callers interested in the number of BlkExprs will want
3504 // the map constructed if it doesn't already exist.
3505 BlkExprMap = (void*) PopulateBlkExprMap(*this);
3506 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size();
3509 //===----------------------------------------------------------------------===//
3510 // Filtered walking of the CFG.
3511 //===----------------------------------------------------------------------===//
3513 bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F,
3514 const CFGBlock *From, const CFGBlock *To) {
3516 if (To && F.IgnoreDefaultsWithCoveredEnums) {
3517 // If the 'To' has no label or is labeled but the label isn't a
3518 // CaseStmt then filter this edge.
3519 if (const SwitchStmt *S =
3520 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) {
3521 if (S->isAllEnumCasesCovered()) {
3522 const Stmt *L = To->getLabel();
3523 if (!L || !isa<CaseStmt>(L))
3532 //===----------------------------------------------------------------------===//
3533 // Cleanup: CFG dstor.
3534 //===----------------------------------------------------------------------===//
3537 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap);
3540 //===----------------------------------------------------------------------===//
3541 // CFG pretty printing
3542 //===----------------------------------------------------------------------===//
3546 class StmtPrinterHelper : public PrinterHelper {
3547 typedef llvm::DenseMap<const Stmt*,std::pair<unsigned,unsigned> > StmtMapTy;
3548 typedef llvm::DenseMap<const Decl*,std::pair<unsigned,unsigned> > DeclMapTy;
3551 signed currentBlock;
3553 const LangOptions &LangOpts;
3556 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO)
3557 : currentBlock(0), currStmt(0), LangOpts(LO)
3559 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) {
3561 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ;
3562 BI != BEnd; ++BI, ++j ) {
3563 if (Optional<CFGStmt> SE = BI->getAs<CFGStmt>()) {
3564 const Stmt *stmt= SE->getStmt();
3565 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j);
3568 switch (stmt->getStmtClass()) {
3569 case Stmt::DeclStmtClass:
3570 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P;
3572 case Stmt::IfStmtClass: {
3573 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable();
3578 case Stmt::ForStmtClass: {
3579 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable();
3584 case Stmt::WhileStmtClass: {
3585 const VarDecl *var =
3586 cast<WhileStmt>(stmt)->getConditionVariable();
3591 case Stmt::SwitchStmtClass: {
3592 const VarDecl *var =
3593 cast<SwitchStmt>(stmt)->getConditionVariable();
3598 case Stmt::CXXCatchStmtClass: {
3599 const VarDecl *var =
3600 cast<CXXCatchStmt>(stmt)->getExceptionDecl();
3614 virtual ~StmtPrinterHelper() {}
3616 const LangOptions &getLangOpts() const { return LangOpts; }
3617 void setBlockID(signed i) { currentBlock = i; }
3618 void setStmtID(unsigned i) { currStmt = i; }
3620 virtual bool handledStmt(Stmt *S, raw_ostream &OS) {
3621 StmtMapTy::iterator I = StmtMap.find(S);
3623 if (I == StmtMap.end())
3626 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
3627 && I->second.second == currStmt) {
3631 OS << "[B" << I->second.first << "." << I->second.second << "]";
3635 bool handleDecl(const Decl *D, raw_ostream &OS) {
3636 DeclMapTy::iterator I = DeclMap.find(D);
3638 if (I == DeclMap.end())
3641 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
3642 && I->second.second == currStmt) {
3646 OS << "[B" << I->second.first << "." << I->second.second << "]";
3650 } // end anonymous namespace
3654 class CFGBlockTerminatorPrint
3655 : public StmtVisitor<CFGBlockTerminatorPrint,void> {
3658 StmtPrinterHelper* Helper;
3659 PrintingPolicy Policy;
3661 CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper,
3662 const PrintingPolicy &Policy)
3663 : OS(os), Helper(helper), Policy(Policy) {}
3665 void VisitIfStmt(IfStmt *I) {
3667 I->getCond()->printPretty(OS,Helper,Policy);
3671 void VisitStmt(Stmt *Terminator) {
3672 Terminator->printPretty(OS, Helper, Policy);
3675 void VisitDeclStmt(DeclStmt *DS) {
3676 VarDecl *VD = cast<VarDecl>(DS->getSingleDecl());
3677 OS << "static init " << VD->getName();
3680 void VisitForStmt(ForStmt *F) {
3685 if (Stmt *C = F->getCond())
3686 C->printPretty(OS, Helper, Policy);
3693 void VisitWhileStmt(WhileStmt *W) {
3695 if (Stmt *C = W->getCond())
3696 C->printPretty(OS, Helper, Policy);
3699 void VisitDoStmt(DoStmt *D) {
3700 OS << "do ... while ";
3701 if (Stmt *C = D->getCond())
3702 C->printPretty(OS, Helper, Policy);
3705 void VisitSwitchStmt(SwitchStmt *Terminator) {
3707 Terminator->getCond()->printPretty(OS, Helper, Policy);
3710 void VisitCXXTryStmt(CXXTryStmt *CS) {
3714 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) {
3715 C->getCond()->printPretty(OS, Helper, Policy);
3716 OS << " ? ... : ...";
3719 void VisitChooseExpr(ChooseExpr *C) {
3720 OS << "__builtin_choose_expr( ";
3721 C->getCond()->printPretty(OS, Helper, Policy);
3725 void VisitIndirectGotoStmt(IndirectGotoStmt *I) {
3727 I->getTarget()->printPretty(OS, Helper, Policy);
3730 void VisitBinaryOperator(BinaryOperator* B) {
3731 if (!B->isLogicalOp()) {
3736 B->getLHS()->printPretty(OS, Helper, Policy);
3738 switch (B->getOpcode()) {
3746 llvm_unreachable("Invalid logical operator.");
3750 void VisitExpr(Expr *E) {
3751 E->printPretty(OS, Helper, Policy);
3754 } // end anonymous namespace
3756 static void print_elem(raw_ostream &OS, StmtPrinterHelper* Helper,
3757 const CFGElement &E) {
3758 if (Optional<CFGStmt> CS = E.getAs<CFGStmt>()) {
3759 const Stmt *S = CS->getStmt();
3763 // special printing for statement-expressions.
3764 if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) {
3765 const CompoundStmt *Sub = SE->getSubStmt();
3767 if (Sub->children()) {
3769 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS);
3774 // special printing for comma expressions.
3775 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) {
3776 if (B->getOpcode() == BO_Comma) {
3778 Helper->handledStmt(B->getRHS(),OS);
3784 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts()));
3786 if (isa<CXXOperatorCallExpr>(S)) {
3787 OS << " (OperatorCall)";
3789 else if (isa<CXXBindTemporaryExpr>(S)) {
3790 OS << " (BindTemporary)";
3792 else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) {
3793 OS << " (CXXConstructExpr, " << CCE->getType().getAsString() << ")";
3795 else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) {
3796 OS << " (" << CE->getStmtClassName() << ", "
3797 << CE->getCastKindName()
3798 << ", " << CE->getType().getAsString()
3802 // Expressions need a newline.
3806 } else if (Optional<CFGInitializer> IE = E.getAs<CFGInitializer>()) {
3807 const CXXCtorInitializer *I = IE->getInitializer();
3808 if (I->isBaseInitializer())
3809 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName();
3810 else OS << I->getAnyMember()->getName();
3813 if (Expr *IE = I->getInit())
3814 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts()));
3817 if (I->isBaseInitializer())
3818 OS << " (Base initializer)\n";
3819 else OS << " (Member initializer)\n";
3821 } else if (Optional<CFGAutomaticObjDtor> DE =
3822 E.getAs<CFGAutomaticObjDtor>()) {
3823 const VarDecl *VD = DE->getVarDecl();
3824 Helper->handleDecl(VD, OS);
3826 const Type* T = VD->getType().getTypePtr();
3827 if (const ReferenceType* RT = T->getAs<ReferenceType>())
3828 T = RT->getPointeeType().getTypePtr();
3829 T = T->getBaseElementTypeUnsafe();
3831 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()";
3832 OS << " (Implicit destructor)\n";
3834 } else if (Optional<CFGBaseDtor> BE = E.getAs<CFGBaseDtor>()) {
3835 const CXXBaseSpecifier *BS = BE->getBaseSpecifier();
3836 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()";
3837 OS << " (Base object destructor)\n";
3839 } else if (Optional<CFGMemberDtor> ME = E.getAs<CFGMemberDtor>()) {
3840 const FieldDecl *FD = ME->getFieldDecl();
3841 const Type *T = FD->getType()->getBaseElementTypeUnsafe();
3842 OS << "this->" << FD->getName();
3843 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()";
3844 OS << " (Member object destructor)\n";
3846 } else if (Optional<CFGTemporaryDtor> TE = E.getAs<CFGTemporaryDtor>()) {
3847 const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr();
3848 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()";
3849 OS << " (Temporary object destructor)\n";
3853 static void print_block(raw_ostream &OS, const CFG* cfg,
3855 StmtPrinterHelper* Helper, bool print_edges,
3859 Helper->setBlockID(B.getBlockID());
3861 // Print the header.
3863 OS.changeColor(raw_ostream::YELLOW, true);
3865 OS << "\n [B" << B.getBlockID();
3867 if (&B == &cfg->getEntry())
3868 OS << " (ENTRY)]\n";
3869 else if (&B == &cfg->getExit())
3871 else if (&B == cfg->getIndirectGotoBlock())
3872 OS << " (INDIRECT GOTO DISPATCH)]\n";
3879 // Print the label of this block.
3880 if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) {
3885 if (LabelStmt *L = dyn_cast<LabelStmt>(Label))
3887 else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) {
3889 C->getLHS()->printPretty(OS, Helper,
3890 PrintingPolicy(Helper->getLangOpts()));
3893 C->getRHS()->printPretty(OS, Helper,
3894 PrintingPolicy(Helper->getLangOpts()));
3896 } else if (isa<DefaultStmt>(Label))
3898 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) {
3900 if (CS->getExceptionDecl())
3901 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()),
3908 llvm_unreachable("Invalid label statement in CFGBlock.");
3913 // Iterate through the statements in the block and print them.
3916 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ;
3917 I != E ; ++I, ++j ) {
3919 // Print the statement # in the basic block and the statement itself.
3923 OS << llvm::format("%3d", j) << ": ";
3926 Helper->setStmtID(j);
3928 print_elem(OS, Helper, *I);
3931 // Print the terminator of this block.
3932 if (B.getTerminator()) {
3934 OS.changeColor(raw_ostream::GREEN);
3938 if (Helper) Helper->setBlockID(-1);
3940 PrintingPolicy PP(Helper ? Helper->getLangOpts() : LangOptions());
3941 CFGBlockTerminatorPrint TPrinter(OS, Helper, PP);
3942 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt()));
3950 // Print the predecessors of this block.
3951 if (!B.pred_empty()) {
3952 const raw_ostream::Colors Color = raw_ostream::BLUE;
3954 OS.changeColor(Color);
3958 OS << '(' << B.pred_size() << "):";
3962 OS.changeColor(Color);
3964 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end();
3970 OS << " B" << (*I)->getBlockID();
3979 // Print the successors of this block.
3980 if (!B.succ_empty()) {
3981 const raw_ostream::Colors Color = raw_ostream::MAGENTA;
3983 OS.changeColor(Color);
3987 OS << '(' << B.succ_size() << "):";
3991 OS.changeColor(Color);
3993 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end();
4000 OS << " B" << (*I)->getBlockID();
4013 /// dump - A simple pretty printer of a CFG that outputs to stderr.
4014 void CFG::dump(const LangOptions &LO, bool ShowColors) const {
4015 print(llvm::errs(), LO, ShowColors);
4018 /// print - A simple pretty printer of a CFG that outputs to an ostream.
4019 void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const {
4020 StmtPrinterHelper Helper(this, LO);
4022 // Print the entry block.
4023 print_block(OS, this, getEntry(), &Helper, true, ShowColors);
4025 // Iterate through the CFGBlocks and print them one by one.
4026 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) {
4027 // Skip the entry block, because we already printed it.
4028 if (&(**I) == &getEntry() || &(**I) == &getExit())
4031 print_block(OS, this, **I, &Helper, true, ShowColors);
4034 // Print the exit block.
4035 print_block(OS, this, getExit(), &Helper, true, ShowColors);
4040 /// dump - A simply pretty printer of a CFGBlock that outputs to stderr.
4041 void CFGBlock::dump(const CFG* cfg, const LangOptions &LO,
4042 bool ShowColors) const {
4043 print(llvm::errs(), cfg, LO, ShowColors);
4046 /// print - A simple pretty printer of a CFGBlock that outputs to an ostream.
4047 /// Generally this will only be called from CFG::print.
4048 void CFGBlock::print(raw_ostream &OS, const CFG* cfg,
4049 const LangOptions &LO, bool ShowColors) const {
4050 StmtPrinterHelper Helper(cfg, LO);
4051 print_block(OS, cfg, *this, &Helper, true, ShowColors);
4055 /// printTerminator - A simple pretty printer of the terminator of a CFGBlock.
4056 void CFGBlock::printTerminator(raw_ostream &OS,
4057 const LangOptions &LO) const {
4058 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO));
4059 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt()));
4062 Stmt *CFGBlock::getTerminatorCondition() {
4063 Stmt *Terminator = this->Terminator;
4069 switch (Terminator->getStmtClass()) {
4073 case Stmt::ForStmtClass:
4074 E = cast<ForStmt>(Terminator)->getCond();
4077 case Stmt::WhileStmtClass:
4078 E = cast<WhileStmt>(Terminator)->getCond();
4081 case Stmt::DoStmtClass:
4082 E = cast<DoStmt>(Terminator)->getCond();
4085 case Stmt::IfStmtClass:
4086 E = cast<IfStmt>(Terminator)->getCond();
4089 case Stmt::ChooseExprClass:
4090 E = cast<ChooseExpr>(Terminator)->getCond();
4093 case Stmt::IndirectGotoStmtClass:
4094 E = cast<IndirectGotoStmt>(Terminator)->getTarget();
4097 case Stmt::SwitchStmtClass:
4098 E = cast<SwitchStmt>(Terminator)->getCond();
4101 case Stmt::BinaryConditionalOperatorClass:
4102 E = cast<BinaryConditionalOperator>(Terminator)->getCond();
4105 case Stmt::ConditionalOperatorClass:
4106 E = cast<ConditionalOperator>(Terminator)->getCond();
4109 case Stmt::BinaryOperatorClass: // '&&' and '||'
4110 E = cast<BinaryOperator>(Terminator)->getLHS();
4113 case Stmt::ObjCForCollectionStmtClass:
4117 return E ? E->IgnoreParens() : NULL;
4120 //===----------------------------------------------------------------------===//
4121 // CFG Graphviz Visualization
4122 //===----------------------------------------------------------------------===//
4126 static StmtPrinterHelper* GraphHelper;
4129 void CFG::viewCFG(const LangOptions &LO) const {
4131 StmtPrinterHelper H(this, LO);
4133 llvm::ViewGraph(this,"CFG");
4140 struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits {
4142 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
4144 static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) {
4147 std::string OutSStr;
4148 llvm::raw_string_ostream Out(OutSStr);
4149 print_block(Out,Graph, *Node, GraphHelper, false, false);
4150 std::string& OutStr = Out.str();
4152 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
4154 // Process string output to make it nicer...
4155 for (unsigned i = 0; i != OutStr.length(); ++i)
4156 if (OutStr[i] == '\n') { // Left justify
4158 OutStr.insert(OutStr.begin()+i+1, 'l');
4167 } // end namespace llvm