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 "llvm/Support/SaveAndRestore.h"
16 #include "clang/Analysis/CFG.h"
17 #include "clang/AST/ASTContext.h"
18 #include "clang/AST/DeclCXX.h"
19 #include "clang/AST/StmtVisitor.h"
20 #include "clang/AST/PrettyPrinter.h"
21 #include "clang/AST/CharUnits.h"
22 #include "clang/Basic/AttrKinds.h"
23 #include "llvm/Support/GraphWriter.h"
24 #include "llvm/Support/Allocator.h"
25 #include "llvm/Support/Format.h"
26 #include "llvm/ADT/DenseMap.h"
27 #include "llvm/ADT/SmallPtrSet.h"
28 #include "llvm/ADT/OwningPtr.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 /// CFGBuilder - This class implements CFG construction from an AST.
237 /// The builder is stateful: an instance of the builder should be used to only
238 /// construct a single CFG.
242 /// CFGBuilder builder;
243 /// CFG* cfg = builder.BuildAST(stmt1);
245 /// CFG construction is done via a recursive walk of an AST. We actually parse
246 /// the AST in reverse order so that the successor of a basic block is
247 /// constructed prior to its predecessor. This allows us to nicely capture
248 /// implicit fall-throughs without extra basic blocks.
251 typedef BlockScopePosPair JumpTarget;
252 typedef BlockScopePosPair JumpSource;
259 JumpTarget ContinueJumpTarget;
260 JumpTarget BreakJumpTarget;
261 CFGBlock *SwitchTerminatedBlock;
262 CFGBlock *DefaultCaseBlock;
263 CFGBlock *TryTerminatedBlock;
265 // Current position in local scope.
266 LocalScope::const_iterator ScopePos;
268 // LabelMap records the mapping from Label expressions to their jump targets.
269 typedef llvm::DenseMap<LabelDecl*, JumpTarget> LabelMapTy;
272 // A list of blocks that end with a "goto" that must be backpatched to their
273 // resolved targets upon completion of CFG construction.
274 typedef std::vector<JumpSource> BackpatchBlocksTy;
275 BackpatchBlocksTy BackpatchBlocks;
277 // A list of labels whose address has been taken (for indirect gotos).
278 typedef llvm::SmallPtrSet<LabelDecl*, 5> LabelSetTy;
279 LabelSetTy AddressTakenLabels;
282 const CFG::BuildOptions &BuildOpts;
284 // State to track for building switch statements.
285 bool switchExclusivelyCovered;
286 Expr::EvalResult *switchCond;
288 CFG::BuildOptions::ForcedBlkExprs::value_type *cachedEntry;
289 const Stmt *lastLookup;
291 // Caches boolean evaluations of expressions to avoid multiple re-evaluations
292 // during construction of branches for chained logical operators.
293 typedef llvm::DenseMap<Expr *, TryResult> CachedBoolEvalsTy;
294 CachedBoolEvalsTy CachedBoolEvals;
297 explicit CFGBuilder(ASTContext *astContext,
298 const CFG::BuildOptions &buildOpts)
299 : Context(astContext), cfg(new CFG()), // crew a new CFG
300 Block(NULL), Succ(NULL),
301 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL),
302 TryTerminatedBlock(NULL), badCFG(false), BuildOpts(buildOpts),
303 switchExclusivelyCovered(false), switchCond(0),
304 cachedEntry(0), lastLookup(0) {}
306 // buildCFG - Used by external clients to construct the CFG.
307 CFG* buildCFG(const Decl *D, Stmt *Statement);
309 bool alwaysAdd(const Stmt *stmt);
312 // Visitors to walk an AST and construct the CFG.
313 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc);
314 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc);
315 CFGBlock *VisitBreakStmt(BreakStmt *B);
316 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc);
317 CFGBlock *VisitCaseStmt(CaseStmt *C);
318 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc);
319 CFGBlock *VisitCompoundStmt(CompoundStmt *C);
320 CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C,
322 CFGBlock *VisitContinueStmt(ContinueStmt *C);
323 CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
325 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S);
326 CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc);
327 CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S);
328 CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
330 CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
332 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T);
333 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S);
334 CFGBlock *VisitDeclStmt(DeclStmt *DS);
335 CFGBlock *VisitDeclSubExpr(DeclStmt *DS);
336 CFGBlock *VisitDefaultStmt(DefaultStmt *D);
337 CFGBlock *VisitDoStmt(DoStmt *D);
338 CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, AddStmtChoice asc);
339 CFGBlock *VisitForStmt(ForStmt *F);
340 CFGBlock *VisitGotoStmt(GotoStmt *G);
341 CFGBlock *VisitIfStmt(IfStmt *I);
342 CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc);
343 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I);
344 CFGBlock *VisitLabelStmt(LabelStmt *L);
345 CFGBlock *VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc);
346 CFGBlock *VisitLogicalOperator(BinaryOperator *B);
347 std::pair<CFGBlock *, CFGBlock *> VisitLogicalOperator(BinaryOperator *B,
350 CFGBlock *FalseBlock);
351 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc);
352 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S);
353 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S);
354 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S);
355 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S);
356 CFGBlock *VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S);
357 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S);
358 CFGBlock *VisitPseudoObjectExpr(PseudoObjectExpr *E);
359 CFGBlock *VisitReturnStmt(ReturnStmt *R);
360 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc);
361 CFGBlock *VisitSwitchStmt(SwitchStmt *S);
362 CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
364 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc);
365 CFGBlock *VisitWhileStmt(WhileStmt *W);
367 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd);
368 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc);
369 CFGBlock *VisitChildren(Stmt *S);
370 CFGBlock *VisitNoRecurse(Expr *E, AddStmtChoice asc);
372 // Visitors to walk an AST and generate destructors of temporaries in
374 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false);
375 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E);
376 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E);
377 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E,
378 bool BindToTemporary);
380 VisitConditionalOperatorForTemporaryDtors(AbstractConditionalOperator *E,
381 bool BindToTemporary);
383 // NYS == Not Yet Supported
389 void autoCreateBlock() { if (!Block) Block = createBlock(); }
390 CFGBlock *createBlock(bool add_successor = true);
391 CFGBlock *createNoReturnBlock();
393 CFGBlock *addStmt(Stmt *S) {
394 return Visit(S, AddStmtChoice::AlwaysAdd);
396 CFGBlock *addInitializer(CXXCtorInitializer *I);
397 void addAutomaticObjDtors(LocalScope::const_iterator B,
398 LocalScope::const_iterator E, Stmt *S);
399 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD);
401 // Local scopes creation.
402 LocalScope* createOrReuseLocalScope(LocalScope* Scope);
404 void addLocalScopeForStmt(Stmt *S);
405 LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS, LocalScope* Scope = NULL);
406 LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = NULL);
408 void addLocalScopeAndDtors(Stmt *S);
410 // Interface to CFGBlock - adding CFGElements.
411 void appendStmt(CFGBlock *B, const Stmt *S) {
412 if (alwaysAdd(S) && cachedEntry)
413 cachedEntry->second = B;
415 // All block-level expressions should have already been IgnoreParens()ed.
416 assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S);
417 B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext());
419 void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) {
420 B->appendInitializer(I, cfg->getBumpVectorContext());
422 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) {
423 B->appendBaseDtor(BS, cfg->getBumpVectorContext());
425 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) {
426 B->appendMemberDtor(FD, cfg->getBumpVectorContext());
428 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) {
429 B->appendTemporaryDtor(E, cfg->getBumpVectorContext());
431 void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) {
432 B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext());
435 void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
436 LocalScope::const_iterator B, LocalScope::const_iterator E);
438 void addSuccessor(CFGBlock *B, CFGBlock *S) {
439 B->addSuccessor(S, cfg->getBumpVectorContext());
442 /// Try and evaluate an expression to an integer constant.
443 bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) {
444 if (!BuildOpts.PruneTriviallyFalseEdges)
446 return !S->isTypeDependent() &&
447 !S->isValueDependent() &&
448 S->EvaluateAsRValue(outResult, *Context);
451 /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1
452 /// if we can evaluate to a known value, otherwise return -1.
453 TryResult tryEvaluateBool(Expr *S) {
454 if (!BuildOpts.PruneTriviallyFalseEdges ||
455 S->isTypeDependent() || S->isValueDependent())
458 if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(S)) {
459 if (Bop->isLogicalOp()) {
460 // Check the cache first.
461 CachedBoolEvalsTy::iterator I = CachedBoolEvals.find(S);
462 if (I != CachedBoolEvals.end())
463 return I->second; // already in map;
465 // Retrieve result at first, or the map might be updated.
466 TryResult Result = evaluateAsBooleanConditionNoCache(S);
467 CachedBoolEvals[S] = Result; // update or insert
471 switch (Bop->getOpcode()) {
473 // For 'x & 0' and 'x * 0', we can determine that
474 // the value is always false.
477 // If either operand is zero, we know the value
480 if (Bop->getLHS()->EvaluateAsInt(IntVal, *Context)) {
481 if (IntVal.getBoolValue() == false) {
482 return TryResult(false);
485 if (Bop->getRHS()->EvaluateAsInt(IntVal, *Context)) {
486 if (IntVal.getBoolValue() == false) {
487 return TryResult(false);
496 return evaluateAsBooleanConditionNoCache(S);
499 /// \brief Evaluate as boolean \param E without using the cache.
500 TryResult evaluateAsBooleanConditionNoCache(Expr *E) {
501 if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(E)) {
502 if (Bop->isLogicalOp()) {
503 TryResult LHS = tryEvaluateBool(Bop->getLHS());
505 // We were able to evaluate the LHS, see if we can get away with not
506 // evaluating the RHS: 0 && X -> 0, 1 || X -> 1
507 if (LHS.isTrue() == (Bop->getOpcode() == BO_LOr))
510 TryResult RHS = tryEvaluateBool(Bop->getRHS());
512 if (Bop->getOpcode() == BO_LOr)
513 return LHS.isTrue() || RHS.isTrue();
515 return LHS.isTrue() && RHS.isTrue();
518 TryResult RHS = tryEvaluateBool(Bop->getRHS());
520 // We can't evaluate the LHS; however, sometimes the result
521 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1.
522 if (RHS.isTrue() == (Bop->getOpcode() == BO_LOr))
532 if (E->EvaluateAsBooleanCondition(Result, *Context))
540 inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder,
541 const Stmt *stmt) const {
542 return builder.alwaysAdd(stmt) || kind == AlwaysAdd;
545 bool CFGBuilder::alwaysAdd(const Stmt *stmt) {
546 bool shouldAdd = BuildOpts.alwaysAdd(stmt);
548 if (!BuildOpts.forcedBlkExprs)
551 if (lastLookup == stmt) {
553 assert(cachedEntry->first == stmt);
561 // Perform the lookup!
562 CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs;
565 // No need to update 'cachedEntry', since it will always be null.
566 assert(cachedEntry == 0);
570 CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt);
571 if (itr == fb->end()) {
580 // FIXME: Add support for dependent-sized array types in C++?
581 // Does it even make sense to build a CFG for an uninstantiated template?
582 static const VariableArrayType *FindVA(const Type *t) {
583 while (const ArrayType *vt = dyn_cast<ArrayType>(t)) {
584 if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt))
585 if (vat->getSizeExpr())
588 t = vt->getElementType().getTypePtr();
594 /// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an
595 /// arbitrary statement. Examples include a single expression or a function
596 /// body (compound statement). The ownership of the returned CFG is
597 /// transferred to the caller. If CFG construction fails, this method returns
599 CFG* CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) {
604 // Create an empty block that will serve as the exit block for the CFG. Since
605 // this is the first block added to the CFG, it will be implicitly registered
606 // as the exit block.
607 Succ = createBlock();
608 assert(Succ == &cfg->getExit());
609 Block = NULL; // the EXIT block is empty. Create all other blocks lazily.
611 if (BuildOpts.AddImplicitDtors)
612 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D))
613 addImplicitDtorsForDestructor(DD);
615 // Visit the statements and create the CFG.
616 CFGBlock *B = addStmt(Statement);
621 // For C++ constructor add initializers to CFG.
622 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) {
623 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(),
624 E = CD->init_rend(); I != E; ++I) {
625 B = addInitializer(*I);
634 // Backpatch the gotos whose label -> block mappings we didn't know when we
636 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(),
637 E = BackpatchBlocks.end(); I != E; ++I ) {
639 CFGBlock *B = I->block;
640 GotoStmt *G = cast<GotoStmt>(B->getTerminator());
641 LabelMapTy::iterator LI = LabelMap.find(G->getLabel());
643 // If there is no target for the goto, then we are looking at an
644 // incomplete AST. Handle this by not registering a successor.
645 if (LI == LabelMap.end()) continue;
647 JumpTarget JT = LI->second;
648 prependAutomaticObjDtorsWithTerminator(B, I->scopePosition,
650 addSuccessor(B, JT.block);
653 // Add successors to the Indirect Goto Dispatch block (if we have one).
654 if (CFGBlock *B = cfg->getIndirectGotoBlock())
655 for (LabelSetTy::iterator I = AddressTakenLabels.begin(),
656 E = AddressTakenLabels.end(); I != E; ++I ) {
658 // Lookup the target block.
659 LabelMapTy::iterator LI = LabelMap.find(*I);
661 // If there is no target block that contains label, then we are looking
662 // at an incomplete AST. Handle this by not registering a successor.
663 if (LI == LabelMap.end()) continue;
665 addSuccessor(B, LI->second.block);
668 // Create an empty entry block that has no predecessors.
669 cfg->setEntry(createBlock());
674 /// createBlock - Used to lazily create blocks that are connected
675 /// to the current (global) succcessor.
676 CFGBlock *CFGBuilder::createBlock(bool add_successor) {
677 CFGBlock *B = cfg->createBlock();
678 if (add_successor && Succ)
679 addSuccessor(B, Succ);
683 /// createNoReturnBlock - Used to create a block is a 'noreturn' point in the
684 /// CFG. It is *not* connected to the current (global) successor, and instead
685 /// directly tied to the exit block in order to be reachable.
686 CFGBlock *CFGBuilder::createNoReturnBlock() {
687 CFGBlock *B = createBlock(false);
688 B->setHasNoReturnElement();
689 addSuccessor(B, &cfg->getExit());
693 /// addInitializer - Add C++ base or member initializer element to CFG.
694 CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) {
695 if (!BuildOpts.AddInitializers)
698 bool IsReference = false;
699 bool HasTemporaries = false;
701 // Destructors of temporaries in initialization expression should be called
702 // after initialization finishes.
703 Expr *Init = I->getInit();
705 if (FieldDecl *FD = I->getAnyMember())
706 IsReference = FD->getType()->isReferenceType();
707 HasTemporaries = isa<ExprWithCleanups>(Init);
709 if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
710 // Generate destructors for temporaries in initialization expression.
711 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
717 appendInitializer(Block, I);
720 if (HasTemporaries) {
721 // For expression with temporaries go directly to subexpression to omit
722 // generating destructors for the second time.
723 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr());
731 /// \brief Retrieve the type of the temporary object whose lifetime was
732 /// extended by a local reference with the given initializer.
733 static QualType getReferenceInitTemporaryType(ASTContext &Context,
737 Init = Init->IgnoreParens();
739 // Skip through cleanups.
740 if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Init)) {
741 Init = EWC->getSubExpr();
745 // Skip through the temporary-materialization expression.
746 if (const MaterializeTemporaryExpr *MTE
747 = dyn_cast<MaterializeTemporaryExpr>(Init)) {
748 Init = MTE->GetTemporaryExpr();
752 // Skip derived-to-base and no-op casts.
753 if (const CastExpr *CE = dyn_cast<CastExpr>(Init)) {
754 if ((CE->getCastKind() == CK_DerivedToBase ||
755 CE->getCastKind() == CK_UncheckedDerivedToBase ||
756 CE->getCastKind() == CK_NoOp) &&
757 Init->getType()->isRecordType()) {
758 Init = CE->getSubExpr();
763 // Skip member accesses into rvalues.
764 if (const MemberExpr *ME = dyn_cast<MemberExpr>(Init)) {
765 if (!ME->isArrow() && ME->getBase()->isRValue()) {
766 Init = ME->getBase();
774 return Init->getType();
777 /// addAutomaticObjDtors - Add to current block automatic objects destructors
778 /// for objects in range of local scope positions. Use S as trigger statement
780 void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B,
781 LocalScope::const_iterator E, Stmt *S) {
782 if (!BuildOpts.AddImplicitDtors)
788 // We need to append the destructors in reverse order, but any one of them
789 // may be a no-return destructor which changes the CFG. As a result, buffer
790 // this sequence up and replay them in reverse order when appending onto the
792 SmallVector<VarDecl*, 10> Decls;
793 Decls.reserve(B.distance(E));
794 for (LocalScope::const_iterator I = B; I != E; ++I)
797 for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(),
800 // If this destructor is marked as a no-return destructor, we need to
801 // create a new block for the destructor which does not have as a successor
802 // anything built thus far: control won't flow out of this block.
803 QualType Ty = (*I)->getType();
804 if (Ty->isReferenceType()) {
805 Ty = getReferenceInitTemporaryType(*Context, (*I)->getInit());
807 Ty = Context->getBaseElementType(Ty);
809 const CXXDestructorDecl *Dtor = Ty->getAsCXXRecordDecl()->getDestructor();
810 if (cast<FunctionType>(Dtor->getType())->getNoReturnAttr())
811 Block = createNoReturnBlock();
815 appendAutomaticObjDtor(Block, *I, S);
819 /// addImplicitDtorsForDestructor - Add implicit destructors generated for
820 /// base and member objects in destructor.
821 void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) {
822 assert (BuildOpts.AddImplicitDtors
823 && "Can be called only when dtors should be added");
824 const CXXRecordDecl *RD = DD->getParent();
826 // At the end destroy virtual base objects.
827 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(),
828 VE = RD->vbases_end(); VI != VE; ++VI) {
829 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl();
830 if (!CD->hasTrivialDestructor()) {
832 appendBaseDtor(Block, VI);
836 // Before virtual bases destroy direct base objects.
837 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(),
838 BE = RD->bases_end(); BI != BE; ++BI) {
839 if (!BI->isVirtual()) {
840 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl();
841 if (!CD->hasTrivialDestructor()) {
843 appendBaseDtor(Block, BI);
848 // First destroy member objects.
849 for (CXXRecordDecl::field_iterator FI = RD->field_begin(),
850 FE = RD->field_end(); FI != FE; ++FI) {
851 // Check for constant size array. Set type to array element type.
852 QualType QT = FI->getType();
853 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
854 if (AT->getSize() == 0)
856 QT = AT->getElementType();
859 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
860 if (!CD->hasTrivialDestructor()) {
862 appendMemberDtor(Block, *FI);
867 /// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either
868 /// way return valid LocalScope object.
869 LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) {
871 llvm::BumpPtrAllocator &alloc = cfg->getAllocator();
872 Scope = alloc.Allocate<LocalScope>();
873 BumpVectorContext ctx(alloc);
874 new (Scope) LocalScope(ctx, ScopePos);
879 /// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement
880 /// that should create implicit scope (e.g. if/else substatements).
881 void CFGBuilder::addLocalScopeForStmt(Stmt *S) {
882 if (!BuildOpts.AddImplicitDtors)
885 LocalScope *Scope = 0;
887 // For compound statement we will be creating explicit scope.
888 if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
889 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end()
891 Stmt *SI = (*BI)->stripLabelLikeStatements();
892 if (DeclStmt *DS = dyn_cast<DeclStmt>(SI))
893 Scope = addLocalScopeForDeclStmt(DS, Scope);
898 // For any other statement scope will be implicit and as such will be
899 // interesting only for DeclStmt.
900 if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements()))
901 addLocalScopeForDeclStmt(DS);
904 /// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will
905 /// reuse Scope if not NULL.
906 LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS,
908 if (!BuildOpts.AddImplicitDtors)
911 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end()
913 if (VarDecl *VD = dyn_cast<VarDecl>(*DI))
914 Scope = addLocalScopeForVarDecl(VD, Scope);
919 /// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will
920 /// create add scope for automatic objects and temporary objects bound to
921 /// const reference. Will reuse Scope if not NULL.
922 LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD,
924 if (!BuildOpts.AddImplicitDtors)
927 // Check if variable is local.
928 switch (VD->getStorageClass()) {
933 default: return Scope;
936 // Check for const references bound to temporary. Set type to pointee.
937 QualType QT = VD->getType();
938 if (QT.getTypePtr()->isReferenceType()) {
939 if (!VD->extendsLifetimeOfTemporary())
942 QT = getReferenceInitTemporaryType(*Context, VD->getInit());
945 // Check for constant size array. Set type to array element type.
946 while (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) {
947 if (AT->getSize() == 0)
949 QT = AT->getElementType();
952 // Check if type is a C++ class with non-trivial destructor.
953 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl())
954 if (!CD->hasTrivialDestructor()) {
955 // Add the variable to scope
956 Scope = createOrReuseLocalScope(Scope);
958 ScopePos = Scope->begin();
963 /// addLocalScopeAndDtors - For given statement add local scope for it and
964 /// add destructors that will cleanup the scope. Will reuse Scope if not NULL.
965 void CFGBuilder::addLocalScopeAndDtors(Stmt *S) {
966 if (!BuildOpts.AddImplicitDtors)
969 LocalScope::const_iterator scopeBeginPos = ScopePos;
970 addLocalScopeForStmt(S);
971 addAutomaticObjDtors(ScopePos, scopeBeginPos, S);
974 /// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for
975 /// variables with automatic storage duration to CFGBlock's elements vector.
976 /// Elements will be prepended to physical beginning of the vector which
977 /// happens to be logical end. Use blocks terminator as statement that specifies
978 /// destructors call site.
979 /// FIXME: This mechanism for adding automatic destructors doesn't handle
980 /// no-return destructors properly.
981 void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
982 LocalScope::const_iterator B, LocalScope::const_iterator E) {
983 BumpVectorContext &C = cfg->getBumpVectorContext();
984 CFGBlock::iterator InsertPos
985 = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C);
986 for (LocalScope::const_iterator I = B; I != E; ++I)
987 InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I,
988 Blk->getTerminator());
991 /// Visit - Walk the subtree of a statement and add extra
992 /// blocks for ternary operators, &&, and ||. We also process "," and
993 /// DeclStmts (which may contain nested control-flow).
994 CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) {
1000 if (Expr *E = dyn_cast<Expr>(S))
1001 S = E->IgnoreParens();
1003 switch (S->getStmtClass()) {
1005 return VisitStmt(S, asc);
1007 case Stmt::AddrLabelExprClass:
1008 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc);
1010 case Stmt::BinaryConditionalOperatorClass:
1011 return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc);
1013 case Stmt::BinaryOperatorClass:
1014 return VisitBinaryOperator(cast<BinaryOperator>(S), asc);
1016 case Stmt::BlockExprClass:
1017 return VisitNoRecurse(cast<Expr>(S), asc);
1019 case Stmt::BreakStmtClass:
1020 return VisitBreakStmt(cast<BreakStmt>(S));
1022 case Stmt::CallExprClass:
1023 case Stmt::CXXOperatorCallExprClass:
1024 case Stmt::CXXMemberCallExprClass:
1025 case Stmt::UserDefinedLiteralClass:
1026 return VisitCallExpr(cast<CallExpr>(S), asc);
1028 case Stmt::CaseStmtClass:
1029 return VisitCaseStmt(cast<CaseStmt>(S));
1031 case Stmt::ChooseExprClass:
1032 return VisitChooseExpr(cast<ChooseExpr>(S), asc);
1034 case Stmt::CompoundStmtClass:
1035 return VisitCompoundStmt(cast<CompoundStmt>(S));
1037 case Stmt::ConditionalOperatorClass:
1038 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc);
1040 case Stmt::ContinueStmtClass:
1041 return VisitContinueStmt(cast<ContinueStmt>(S));
1043 case Stmt::CXXCatchStmtClass:
1044 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S));
1046 case Stmt::ExprWithCleanupsClass:
1047 return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc);
1049 case Stmt::CXXDefaultArgExprClass:
1050 // FIXME: The expression inside a CXXDefaultArgExpr is owned by the
1051 // called function's declaration, not by the caller. If we simply add
1052 // this expression to the CFG, we could end up with the same Expr
1053 // appearing multiple times.
1054 // PR13385 / <rdar://problem/12156507>
1055 return VisitStmt(S, asc);
1057 case Stmt::CXXBindTemporaryExprClass:
1058 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc);
1060 case Stmt::CXXConstructExprClass:
1061 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc);
1063 case Stmt::CXXFunctionalCastExprClass:
1064 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc);
1066 case Stmt::CXXTemporaryObjectExprClass:
1067 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc);
1069 case Stmt::CXXThrowExprClass:
1070 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S));
1072 case Stmt::CXXTryStmtClass:
1073 return VisitCXXTryStmt(cast<CXXTryStmt>(S));
1075 case Stmt::CXXForRangeStmtClass:
1076 return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S));
1078 case Stmt::DeclStmtClass:
1079 return VisitDeclStmt(cast<DeclStmt>(S));
1081 case Stmt::DefaultStmtClass:
1082 return VisitDefaultStmt(cast<DefaultStmt>(S));
1084 case Stmt::DoStmtClass:
1085 return VisitDoStmt(cast<DoStmt>(S));
1087 case Stmt::ForStmtClass:
1088 return VisitForStmt(cast<ForStmt>(S));
1090 case Stmt::GotoStmtClass:
1091 return VisitGotoStmt(cast<GotoStmt>(S));
1093 case Stmt::IfStmtClass:
1094 return VisitIfStmt(cast<IfStmt>(S));
1096 case Stmt::ImplicitCastExprClass:
1097 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc);
1099 case Stmt::IndirectGotoStmtClass:
1100 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S));
1102 case Stmt::LabelStmtClass:
1103 return VisitLabelStmt(cast<LabelStmt>(S));
1105 case Stmt::LambdaExprClass:
1106 return VisitLambdaExpr(cast<LambdaExpr>(S), asc);
1108 case Stmt::MemberExprClass:
1109 return VisitMemberExpr(cast<MemberExpr>(S), asc);
1111 case Stmt::NullStmtClass:
1114 case Stmt::ObjCAtCatchStmtClass:
1115 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S));
1117 case Stmt::ObjCAutoreleasePoolStmtClass:
1118 return VisitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(S));
1120 case Stmt::ObjCAtSynchronizedStmtClass:
1121 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S));
1123 case Stmt::ObjCAtThrowStmtClass:
1124 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S));
1126 case Stmt::ObjCAtTryStmtClass:
1127 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S));
1129 case Stmt::ObjCForCollectionStmtClass:
1130 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S));
1132 case Stmt::OpaqueValueExprClass:
1135 case Stmt::PseudoObjectExprClass:
1136 return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S));
1138 case Stmt::ReturnStmtClass:
1139 return VisitReturnStmt(cast<ReturnStmt>(S));
1141 case Stmt::UnaryExprOrTypeTraitExprClass:
1142 return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S),
1145 case Stmt::StmtExprClass:
1146 return VisitStmtExpr(cast<StmtExpr>(S), asc);
1148 case Stmt::SwitchStmtClass:
1149 return VisitSwitchStmt(cast<SwitchStmt>(S));
1151 case Stmt::UnaryOperatorClass:
1152 return VisitUnaryOperator(cast<UnaryOperator>(S), asc);
1154 case Stmt::WhileStmtClass:
1155 return VisitWhileStmt(cast<WhileStmt>(S));
1159 CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) {
1160 if (asc.alwaysAdd(*this, S)) {
1162 appendStmt(Block, S);
1165 return VisitChildren(S);
1168 /// VisitChildren - Visit the children of a Stmt.
1169 CFGBlock *CFGBuilder::VisitChildren(Stmt *Terminator) {
1170 CFGBlock *lastBlock = Block;
1171 for (Stmt::child_range I = Terminator->children(); I; ++I)
1172 if (Stmt *child = *I)
1173 if (CFGBlock *b = Visit(child))
1179 CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A,
1180 AddStmtChoice asc) {
1181 AddressTakenLabels.insert(A->getLabel());
1183 if (asc.alwaysAdd(*this, A)) {
1185 appendStmt(Block, A);
1191 CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U,
1192 AddStmtChoice asc) {
1193 if (asc.alwaysAdd(*this, U)) {
1195 appendStmt(Block, U);
1198 return Visit(U->getSubExpr(), AddStmtChoice());
1201 CFGBlock *CFGBuilder::VisitLogicalOperator(BinaryOperator *B) {
1202 CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
1203 appendStmt(ConfluenceBlock, B);
1208 return VisitLogicalOperator(B, 0, ConfluenceBlock, ConfluenceBlock).first;
1211 std::pair<CFGBlock*, CFGBlock*>
1212 CFGBuilder::VisitLogicalOperator(BinaryOperator *B,
1214 CFGBlock *TrueBlock,
1215 CFGBlock *FalseBlock) {
1217 // Introspect the RHS. If it is a nested logical operation, we recursively
1218 // build the CFG using this function. Otherwise, resort to default
1219 // CFG construction behavior.
1220 Expr *RHS = B->getRHS()->IgnoreParens();
1221 CFGBlock *RHSBlock, *ExitBlock;
1224 if (BinaryOperator *B_RHS = dyn_cast<BinaryOperator>(RHS))
1225 if (B_RHS->isLogicalOp()) {
1226 llvm::tie(RHSBlock, ExitBlock) =
1227 VisitLogicalOperator(B_RHS, Term, TrueBlock, FalseBlock);
1231 // The RHS is not a nested logical operation. Don't push the terminator
1232 // down further, but instead visit RHS and construct the respective
1233 // pieces of the CFG, and link up the RHSBlock with the terminator
1234 // we have been provided.
1235 ExitBlock = RHSBlock = createBlock(false);
1238 assert(TrueBlock == FalseBlock);
1239 addSuccessor(RHSBlock, TrueBlock);
1242 RHSBlock->setTerminator(Term);
1243 TryResult KnownVal = tryEvaluateBool(RHS);
1244 addSuccessor(RHSBlock, KnownVal.isFalse() ? NULL : TrueBlock);
1245 addSuccessor(RHSBlock, KnownVal.isTrue() ? NULL : FalseBlock);
1249 RHSBlock = addStmt(RHS);
1254 return std::make_pair((CFGBlock*)0, (CFGBlock*)0);
1256 // Generate the blocks for evaluating the LHS.
1257 Expr *LHS = B->getLHS()->IgnoreParens();
1259 if (BinaryOperator *B_LHS = dyn_cast<BinaryOperator>(LHS))
1260 if (B_LHS->isLogicalOp()) {
1261 if (B->getOpcode() == BO_LOr)
1262 FalseBlock = RHSBlock;
1264 TrueBlock = RHSBlock;
1266 // For the LHS, treat 'B' as the terminator that we want to sink
1267 // into the nested branch. The RHS always gets the top-most
1269 return VisitLogicalOperator(B_LHS, B, TrueBlock, FalseBlock);
1272 // Create the block evaluating the LHS.
1273 // This contains the '&&' or '||' as the terminator.
1274 CFGBlock *LHSBlock = createBlock(false);
1275 LHSBlock->setTerminator(B);
1278 CFGBlock *EntryLHSBlock = addStmt(LHS);
1281 return std::make_pair((CFGBlock*)0, (CFGBlock*)0);
1283 // See if this is a known constant.
1284 TryResult KnownVal = tryEvaluateBool(LHS);
1286 // Now link the LHSBlock with RHSBlock.
1287 if (B->getOpcode() == BO_LOr) {
1288 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : TrueBlock);
1289 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : RHSBlock);
1291 assert(B->getOpcode() == BO_LAnd);
1292 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock);
1293 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : FalseBlock);
1296 return std::make_pair(EntryLHSBlock, ExitBlock);
1300 CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B,
1301 AddStmtChoice asc) {
1303 if (B->isLogicalOp())
1304 return VisitLogicalOperator(B);
1306 if (B->getOpcode() == BO_Comma) { // ,
1308 appendStmt(Block, B);
1309 addStmt(B->getRHS());
1310 return addStmt(B->getLHS());
1313 if (B->isAssignmentOp()) {
1314 if (asc.alwaysAdd(*this, B)) {
1316 appendStmt(Block, B);
1319 return Visit(B->getRHS());
1322 if (asc.alwaysAdd(*this, B)) {
1324 appendStmt(Block, B);
1327 CFGBlock *RBlock = Visit(B->getRHS());
1328 CFGBlock *LBlock = Visit(B->getLHS());
1329 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr
1330 // containing a DoStmt, and the LHS doesn't create a new block, then we should
1331 // return RBlock. Otherwise we'll incorrectly return NULL.
1332 return (LBlock ? LBlock : RBlock);
1335 CFGBlock *CFGBuilder::VisitNoRecurse(Expr *E, AddStmtChoice asc) {
1336 if (asc.alwaysAdd(*this, E)) {
1338 appendStmt(Block, E);
1343 CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) {
1344 // "break" is a control-flow statement. Thus we stop processing the current
1349 // Now create a new block that ends with the break statement.
1350 Block = createBlock(false);
1351 Block->setTerminator(B);
1353 // If there is no target for the break, then we are looking at an incomplete
1354 // AST. This means that the CFG cannot be constructed.
1355 if (BreakJumpTarget.block) {
1356 addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B);
1357 addSuccessor(Block, BreakJumpTarget.block);
1365 static bool CanThrow(Expr *E, ASTContext &Ctx) {
1366 QualType Ty = E->getType();
1367 if (Ty->isFunctionPointerType())
1368 Ty = Ty->getAs<PointerType>()->getPointeeType();
1369 else if (Ty->isBlockPointerType())
1370 Ty = Ty->getAs<BlockPointerType>()->getPointeeType();
1372 const FunctionType *FT = Ty->getAs<FunctionType>();
1374 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT))
1375 if (!isUnresolvedExceptionSpec(Proto->getExceptionSpecType()) &&
1376 Proto->isNothrow(Ctx))
1382 CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) {
1383 // Compute the callee type.
1384 QualType calleeType = C->getCallee()->getType();
1385 if (calleeType == Context->BoundMemberTy) {
1386 QualType boundType = Expr::findBoundMemberType(C->getCallee());
1388 // We should only get a null bound type if processing a dependent
1389 // CFG. Recover by assuming nothing.
1390 if (!boundType.isNull()) calleeType = boundType;
1393 // If this is a call to a no-return function, this stops the block here.
1394 bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn();
1396 bool AddEHEdge = false;
1398 // Languages without exceptions are assumed to not throw.
1399 if (Context->getLangOpts().Exceptions) {
1400 if (BuildOpts.AddEHEdges)
1404 if (FunctionDecl *FD = C->getDirectCallee()) {
1405 if (FD->hasAttr<NoReturnAttr>())
1407 if (FD->hasAttr<NoThrowAttr>())
1411 if (!CanThrow(C->getCallee(), *Context))
1414 if (!NoReturn && !AddEHEdge)
1415 return VisitStmt(C, asc.withAlwaysAdd(true));
1424 Block = createNoReturnBlock();
1426 Block = createBlock();
1428 appendStmt(Block, C);
1431 // Add exceptional edges.
1432 if (TryTerminatedBlock)
1433 addSuccessor(Block, TryTerminatedBlock);
1435 addSuccessor(Block, &cfg->getExit());
1438 return VisitChildren(C);
1441 CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C,
1442 AddStmtChoice asc) {
1443 CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
1444 appendStmt(ConfluenceBlock, C);
1448 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
1449 Succ = ConfluenceBlock;
1451 CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd);
1455 Succ = ConfluenceBlock;
1457 CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd);
1461 Block = createBlock(false);
1462 // See if this is a known constant.
1463 const TryResult& KnownVal = tryEvaluateBool(C->getCond());
1464 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock);
1465 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock);
1466 Block->setTerminator(C);
1467 return addStmt(C->getCond());
1471 CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) {
1472 addLocalScopeAndDtors(C);
1473 CFGBlock *LastBlock = Block;
1475 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend();
1477 // If we hit a segment of code just containing ';' (NullStmts), we can
1478 // get a null block back. In such cases, just use the LastBlock
1479 if (CFGBlock *newBlock = addStmt(*I))
1480 LastBlock = newBlock;
1489 CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C,
1490 AddStmtChoice asc) {
1491 const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C);
1492 const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : NULL);
1494 // Create the confluence block that will "merge" the results of the ternary
1496 CFGBlock *ConfluenceBlock = Block ? Block : createBlock();
1497 appendStmt(ConfluenceBlock, C);
1501 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true);
1503 // Create a block for the LHS expression if there is an LHS expression. A
1504 // GCC extension allows LHS to be NULL, causing the condition to be the
1505 // value that is returned instead.
1506 // e.g: x ?: y is shorthand for: x ? x : y;
1507 Succ = ConfluenceBlock;
1509 CFGBlock *LHSBlock = 0;
1510 const Expr *trueExpr = C->getTrueExpr();
1511 if (trueExpr != opaqueValue) {
1512 LHSBlock = Visit(C->getTrueExpr(), alwaysAdd);
1518 LHSBlock = ConfluenceBlock;
1520 // Create the block for the RHS expression.
1521 Succ = ConfluenceBlock;
1522 CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd);
1526 // If the condition is a logical '&&' or '||', build a more accurate CFG.
1527 if (BinaryOperator *Cond =
1528 dyn_cast<BinaryOperator>(C->getCond()->IgnoreParens()))
1529 if (Cond->isLogicalOp())
1530 return VisitLogicalOperator(Cond, C, LHSBlock, RHSBlock).first;
1532 // Create the block that will contain the condition.
1533 Block = createBlock(false);
1535 // See if this is a known constant.
1536 const TryResult& KnownVal = tryEvaluateBool(C->getCond());
1537 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock);
1538 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock);
1539 Block->setTerminator(C);
1540 Expr *condExpr = C->getCond();
1543 // Run the condition expression if it's not trivially expressed in
1544 // terms of the opaque value (or if there is no opaque value).
1545 if (condExpr != opaqueValue)
1548 // Before that, run the common subexpression if there was one.
1549 // At least one of this or the above will be run.
1550 return addStmt(BCO->getCommon());
1553 return addStmt(condExpr);
1556 CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) {
1557 // Check if the Decl is for an __label__. If so, elide it from the
1559 if (isa<LabelDecl>(*DS->decl_begin()))
1562 // This case also handles static_asserts.
1563 if (DS->isSingleDecl())
1564 return VisitDeclSubExpr(DS);
1568 // Build an individual DeclStmt for each decl.
1569 for (DeclStmt::reverse_decl_iterator I = DS->decl_rbegin(),
1570 E = DS->decl_rend();
1572 // Get the alignment of the new DeclStmt, padding out to >=8 bytes.
1573 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8
1574 ? 8 : llvm::AlignOf<DeclStmt>::Alignment;
1576 // Allocate the DeclStmt using the BumpPtrAllocator. It will get
1577 // automatically freed with the CFG.
1578 DeclGroupRef DG(*I);
1580 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A);
1581 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D));
1583 // Append the fake DeclStmt to block.
1584 B = VisitDeclSubExpr(DSNew);
1590 /// VisitDeclSubExpr - Utility method to add block-level expressions for
1591 /// DeclStmts and initializers in them.
1592 CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) {
1593 assert(DS->isSingleDecl() && "Can handle single declarations only.");
1594 Decl *D = DS->getSingleDecl();
1596 if (isa<StaticAssertDecl>(D)) {
1597 // static_asserts aren't added to the CFG because they do not impact
1598 // runtime semantics.
1602 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl());
1606 appendStmt(Block, DS);
1610 bool IsReference = false;
1611 bool HasTemporaries = false;
1613 // Destructors of temporaries in initialization expression should be called
1614 // after initialization finishes.
1615 Expr *Init = VD->getInit();
1617 IsReference = VD->getType()->isReferenceType();
1618 HasTemporaries = isa<ExprWithCleanups>(Init);
1620 if (BuildOpts.AddTemporaryDtors && HasTemporaries) {
1621 // Generate destructors for temporaries in initialization expression.
1622 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(),
1628 appendStmt(Block, DS);
1630 // Keep track of the last non-null block, as 'Block' can be nulled out
1631 // if the initializer expression is something like a 'while' in a
1632 // statement-expression.
1633 CFGBlock *LastBlock = Block;
1636 if (HasTemporaries) {
1637 // For expression with temporaries go directly to subexpression to omit
1638 // generating destructors for the second time.
1639 ExprWithCleanups *EC = cast<ExprWithCleanups>(Init);
1640 if (CFGBlock *newBlock = Visit(EC->getSubExpr()))
1641 LastBlock = newBlock;
1644 if (CFGBlock *newBlock = Visit(Init))
1645 LastBlock = newBlock;
1649 // If the type of VD is a VLA, then we must process its size expressions.
1650 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr());
1651 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) {
1652 if (CFGBlock *newBlock = addStmt(VA->getSizeExpr()))
1653 LastBlock = newBlock;
1656 // Remove variable from local scope.
1657 if (ScopePos && VD == *ScopePos)
1660 return Block ? Block : LastBlock;
1663 CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) {
1664 // We may see an if statement in the middle of a basic block, or it may be the
1665 // first statement we are processing. In either case, we create a new basic
1666 // block. First, we create the blocks for the then...else statements, and
1667 // then we create the block containing the if statement. If we were in the
1668 // middle of a block, we stop processing that block. That block is then the
1669 // implicit successor for the "then" and "else" clauses.
1671 // Save local scope position because in case of condition variable ScopePos
1672 // won't be restored when traversing AST.
1673 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
1675 // Create local scope for possible condition variable.
1676 // Store scope position. Add implicit destructor.
1677 if (VarDecl *VD = I->getConditionVariable()) {
1678 LocalScope::const_iterator BeginScopePos = ScopePos;
1679 addLocalScopeForVarDecl(VD);
1680 addAutomaticObjDtors(ScopePos, BeginScopePos, I);
1683 // The block we were processing is now finished. Make it the successor
1691 // Process the false branch.
1692 CFGBlock *ElseBlock = Succ;
1694 if (Stmt *Else = I->getElse()) {
1695 SaveAndRestore<CFGBlock*> sv(Succ);
1697 // NULL out Block so that the recursive call to Visit will
1698 // create a new basic block.
1701 // If branch is not a compound statement create implicit scope
1702 // and add destructors.
1703 if (!isa<CompoundStmt>(Else))
1704 addLocalScopeAndDtors(Else);
1706 ElseBlock = addStmt(Else);
1708 if (!ElseBlock) // Can occur when the Else body has all NullStmts.
1709 ElseBlock = sv.get();
1716 // Process the true branch.
1717 CFGBlock *ThenBlock;
1719 Stmt *Then = I->getThen();
1721 SaveAndRestore<CFGBlock*> sv(Succ);
1724 // If branch is not a compound statement create implicit scope
1725 // and add destructors.
1726 if (!isa<CompoundStmt>(Then))
1727 addLocalScopeAndDtors(Then);
1729 ThenBlock = addStmt(Then);
1732 // We can reach here if the "then" body has all NullStmts.
1733 // Create an empty block so we can distinguish between true and false
1734 // branches in path-sensitive analyses.
1735 ThenBlock = createBlock(false);
1736 addSuccessor(ThenBlock, sv.get());
1743 // Specially handle "if (expr1 || ...)" and "if (expr1 && ...)" by
1744 // having these handle the actual control-flow jump. Note that
1745 // if we introduce a condition variable, e.g. "if (int x = exp1 || exp2)"
1746 // we resort to the old control-flow behavior. This special handling
1747 // removes infeasible paths from the control-flow graph by having the
1748 // control-flow transfer of '&&' or '||' go directly into the then/else
1750 if (!I->getConditionVariable())
1751 if (BinaryOperator *Cond =
1752 dyn_cast<BinaryOperator>(I->getCond()->IgnoreParens()))
1753 if (Cond->isLogicalOp())
1754 return VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first;
1756 // Now create a new block containing the if statement.
1757 Block = createBlock(false);
1759 // Set the terminator of the new block to the If statement.
1760 Block->setTerminator(I);
1762 // See if this is a known constant.
1763 const TryResult &KnownVal = tryEvaluateBool(I->getCond());
1765 // Now add the successors.
1766 addSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock);
1767 addSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock);
1769 // Add the condition as the last statement in the new block. This may create
1770 // new blocks as the condition may contain control-flow. Any newly created
1771 // blocks will be pointed to be "Block".
1772 CFGBlock *LastBlock = addStmt(I->getCond());
1774 // Finally, if the IfStmt contains a condition variable, add both the IfStmt
1775 // and the condition variable initialization to the CFG.
1776 if (VarDecl *VD = I->getConditionVariable()) {
1777 if (Expr *Init = VD->getInit()) {
1779 appendStmt(Block, I->getConditionVariableDeclStmt());
1780 LastBlock = addStmt(Init);
1788 CFGBlock *CFGBuilder::VisitReturnStmt(ReturnStmt *R) {
1789 // If we were in the middle of a block we stop processing that block.
1791 // NOTE: If a "return" appears in the middle of a block, this means that the
1792 // code afterwards is DEAD (unreachable). We still keep a basic block
1793 // for that code; a simple "mark-and-sweep" from the entry block will be
1794 // able to report such dead blocks.
1796 // Create the new block.
1797 Block = createBlock(false);
1799 // The Exit block is the only successor.
1800 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R);
1801 addSuccessor(Block, &cfg->getExit());
1803 // Add the return statement to the block. This may create new blocks if R
1804 // contains control-flow (short-circuit operations).
1805 return VisitStmt(R, AddStmtChoice::AlwaysAdd);
1808 CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) {
1809 // Get the block of the labeled statement. Add it to our map.
1810 addStmt(L->getSubStmt());
1811 CFGBlock *LabelBlock = Block;
1813 if (!LabelBlock) // This can happen when the body is empty, i.e.
1814 LabelBlock = createBlock(); // scopes that only contains NullStmts.
1816 assert(LabelMap.find(L->getDecl()) == LabelMap.end() &&
1817 "label already in map");
1818 LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos);
1820 // Labels partition blocks, so this is the end of the basic block we were
1821 // processing (L is the block's label). Because this is label (and we have
1822 // already processed the substatement) there is no extra control-flow to worry
1824 LabelBlock->setLabel(L);
1828 // We set Block to NULL to allow lazy creation of a new block (if necessary);
1831 // This block is now the implicit successor of other blocks.
1837 CFGBlock *CFGBuilder::VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc) {
1838 CFGBlock *LastBlock = VisitNoRecurse(E, asc);
1839 for (LambdaExpr::capture_init_iterator it = E->capture_init_begin(),
1840 et = E->capture_init_end(); it != et; ++it) {
1841 if (Expr *Init = *it) {
1842 CFGBlock *Tmp = Visit(Init);
1850 CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) {
1851 // Goto is a control-flow statement. Thus we stop processing the current
1852 // block and create a new one.
1854 Block = createBlock(false);
1855 Block->setTerminator(G);
1857 // If we already know the mapping to the label block add the successor now.
1858 LabelMapTy::iterator I = LabelMap.find(G->getLabel());
1860 if (I == LabelMap.end())
1861 // We will need to backpatch this block later.
1862 BackpatchBlocks.push_back(JumpSource(Block, ScopePos));
1864 JumpTarget JT = I->second;
1865 addAutomaticObjDtors(ScopePos, JT.scopePosition, G);
1866 addSuccessor(Block, JT.block);
1872 CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) {
1873 CFGBlock *LoopSuccessor = NULL;
1875 // Save local scope position because in case of condition variable ScopePos
1876 // won't be restored when traversing AST.
1877 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
1879 // Create local scope for init statement and possible condition variable.
1880 // Add destructor for init statement and condition variable.
1881 // Store scope position for continue statement.
1882 if (Stmt *Init = F->getInit())
1883 addLocalScopeForStmt(Init);
1884 LocalScope::const_iterator LoopBeginScopePos = ScopePos;
1886 if (VarDecl *VD = F->getConditionVariable())
1887 addLocalScopeForVarDecl(VD);
1888 LocalScope::const_iterator ContinueScopePos = ScopePos;
1890 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F);
1892 // "for" is a control-flow statement. Thus we stop processing the current
1897 LoopSuccessor = Block;
1899 LoopSuccessor = Succ;
1901 // Save the current value for the break targets.
1902 // All breaks should go to the code following the loop.
1903 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
1904 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
1906 CFGBlock *BodyBlock = 0, *TransitionBlock = 0;
1908 // Now create the loop body.
1910 assert(F->getBody());
1912 // Save the current values for Block, Succ, continue and break targets.
1913 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
1914 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
1916 // Create an empty block to represent the transition block for looping back
1917 // to the head of the loop. If we have increment code, it will
1918 // go in this block as well.
1919 Block = Succ = TransitionBlock = createBlock(false);
1920 TransitionBlock->setLoopTarget(F);
1922 if (Stmt *I = F->getInc()) {
1923 // Generate increment code in its own basic block. This is the target of
1924 // continue statements.
1928 // Finish up the increment (or empty) block if it hasn't been already.
1930 assert(Block == Succ);
1936 // The starting block for the loop increment is the block that should
1937 // represent the 'loop target' for looping back to the start of the loop.
1938 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
1939 ContinueJumpTarget.block->setLoopTarget(F);
1941 // Loop body should end with destructor of Condition variable (if any).
1942 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F);
1944 // If body is not a compound statement create implicit scope
1945 // and add destructors.
1946 if (!isa<CompoundStmt>(F->getBody()))
1947 addLocalScopeAndDtors(F->getBody());
1949 // Now populate the body block, and in the process create new blocks as we
1950 // walk the body of the loop.
1951 BodyBlock = addStmt(F->getBody());
1954 // In the case of "for (...;...;...);" we can have a null BodyBlock.
1955 // Use the continue jump target as the proxy for the body.
1956 BodyBlock = ContinueJumpTarget.block;
1962 // Because of short-circuit evaluation, the condition of the loop can span
1963 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
1964 // evaluate the condition.
1965 CFGBlock *EntryConditionBlock = 0, *ExitConditionBlock = 0;
1968 Expr *C = F->getCond();
1970 // Specially handle logical operators, which have a slightly
1971 // more optimal CFG representation.
1972 if (BinaryOperator *Cond =
1973 dyn_cast_or_null<BinaryOperator>(C ? C->IgnoreParens() : 0))
1974 if (Cond->isLogicalOp()) {
1975 llvm::tie(EntryConditionBlock, ExitConditionBlock) =
1976 VisitLogicalOperator(Cond, F, BodyBlock, LoopSuccessor);
1980 // The default case when not handling logical operators.
1981 EntryConditionBlock = ExitConditionBlock = createBlock(false);
1982 ExitConditionBlock->setTerminator(F);
1984 // See if this is a known constant.
1985 TryResult KnownVal(true);
1988 // Now add the actual condition to the condition block.
1989 // Because the condition itself may contain control-flow, new blocks may
1990 // be created. Thus we update "Succ" after adding the condition.
1991 Block = ExitConditionBlock;
1992 EntryConditionBlock = addStmt(C);
1994 // If this block contains a condition variable, add both the condition
1995 // variable and initializer to the CFG.
1996 if (VarDecl *VD = F->getConditionVariable()) {
1997 if (Expr *Init = VD->getInit()) {
1999 appendStmt(Block, F->getConditionVariableDeclStmt());
2000 EntryConditionBlock = addStmt(Init);
2001 assert(Block == EntryConditionBlock);
2005 if (Block && badCFG)
2008 KnownVal = tryEvaluateBool(C);
2011 // Add the loop body entry as a successor to the condition.
2012 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock);
2013 // Link up the condition block with the code that follows the loop. (the
2015 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor);
2019 // Link up the loop-back block to the entry condition block.
2020 addSuccessor(TransitionBlock, EntryConditionBlock);
2022 // The condition block is the implicit successor for any code above the loop.
2023 Succ = EntryConditionBlock;
2025 // If the loop contains initialization, create a new block for those
2026 // statements. This block can also contain statements that precede the loop.
2027 if (Stmt *I = F->getInit()) {
2028 Block = createBlock();
2032 // There is no loop initialization. We are thus basically a while loop.
2033 // NULL out Block to force lazy block construction.
2035 Succ = EntryConditionBlock;
2036 return EntryConditionBlock;
2039 CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) {
2040 if (asc.alwaysAdd(*this, M)) {
2042 appendStmt(Block, M);
2044 return Visit(M->getBase());
2047 CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) {
2048 // Objective-C fast enumeration 'for' statements:
2049 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC
2051 // for ( Type newVariable in collection_expression ) { statements }
2056 // 1. collection_expression
2057 // T. jump to loop_entry
2059 // 1. side-effects of element expression
2060 // 1. ObjCForCollectionStmt [performs binding to newVariable]
2061 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil]
2064 // T. jump to loop_entry
2070 // Type existingItem;
2071 // for ( existingItem in expression ) { statements }
2075 // the same with newVariable replaced with existingItem; the binding works
2076 // the same except that for one ObjCForCollectionStmt::getElement() returns
2077 // a DeclStmt and the other returns a DeclRefExpr.
2080 CFGBlock *LoopSuccessor = 0;
2085 LoopSuccessor = Block;
2088 LoopSuccessor = Succ;
2090 // Build the condition blocks.
2091 CFGBlock *ExitConditionBlock = createBlock(false);
2093 // Set the terminator for the "exit" condition block.
2094 ExitConditionBlock->setTerminator(S);
2096 // The last statement in the block should be the ObjCForCollectionStmt, which
2097 // performs the actual binding to 'element' and determines if there are any
2098 // more items in the collection.
2099 appendStmt(ExitConditionBlock, S);
2100 Block = ExitConditionBlock;
2102 // Walk the 'element' expression to see if there are any side-effects. We
2103 // generate new blocks as necessary. We DON'T add the statement by default to
2104 // the CFG unless it contains control-flow.
2105 CFGBlock *EntryConditionBlock = Visit(S->getElement(),
2106 AddStmtChoice::NotAlwaysAdd);
2113 // The condition block is the implicit successor for the loop body as well as
2114 // any code above the loop.
2115 Succ = EntryConditionBlock;
2117 // Now create the true branch.
2119 // Save the current values for Succ, continue and break targets.
2120 SaveAndRestore<CFGBlock*> save_Succ(Succ);
2121 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
2122 save_break(BreakJumpTarget);
2124 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
2125 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos);
2127 CFGBlock *BodyBlock = addStmt(S->getBody());
2130 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;"
2136 // This new body block is a successor to our "exit" condition block.
2137 addSuccessor(ExitConditionBlock, BodyBlock);
2140 // Link up the condition block with the code that follows the loop.
2141 // (the false branch).
2142 addSuccessor(ExitConditionBlock, LoopSuccessor);
2144 // Now create a prologue block to contain the collection expression.
2145 Block = createBlock();
2146 return addStmt(S->getCollection());
2149 CFGBlock *CFGBuilder::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) {
2151 return addStmt(S->getSubStmt());
2152 // TODO: consider adding cleanups for the end of @autoreleasepool scope.
2155 CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) {
2156 // FIXME: Add locking 'primitives' to CFG for @synchronized.
2159 CFGBlock *SyncBlock = addStmt(S->getSynchBody());
2161 // The sync body starts its own basic block. This makes it a little easier
2162 // for diagnostic clients.
2171 // Add the @synchronized to the CFG.
2173 appendStmt(Block, S);
2175 // Inline the sync expression.
2176 return addStmt(S->getSynchExpr());
2179 CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) {
2184 CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) {
2187 // Add the PseudoObject as the last thing.
2188 appendStmt(Block, E);
2190 CFGBlock *lastBlock = Block;
2192 // Before that, evaluate all of the semantics in order. In
2193 // CFG-land, that means appending them in reverse order.
2194 for (unsigned i = E->getNumSemanticExprs(); i != 0; ) {
2195 Expr *Semantic = E->getSemanticExpr(--i);
2197 // If the semantic is an opaque value, we're being asked to bind
2198 // it to its source expression.
2199 if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic))
2200 Semantic = OVE->getSourceExpr();
2202 if (CFGBlock *B = Visit(Semantic))
2209 CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) {
2210 CFGBlock *LoopSuccessor = NULL;
2212 // Save local scope position because in case of condition variable ScopePos
2213 // won't be restored when traversing AST.
2214 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2216 // Create local scope for possible condition variable.
2217 // Store scope position for continue statement.
2218 LocalScope::const_iterator LoopBeginScopePos = ScopePos;
2219 if (VarDecl *VD = W->getConditionVariable()) {
2220 addLocalScopeForVarDecl(VD);
2221 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W);
2224 // "while" is a control-flow statement. Thus we stop processing the current
2229 LoopSuccessor = Block;
2232 LoopSuccessor = Succ;
2235 CFGBlock *BodyBlock = 0, *TransitionBlock = 0;
2237 // Process the loop body.
2239 assert(W->getBody());
2241 // Save the current values for Block, Succ, continue and break targets.
2242 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
2243 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
2244 save_break(BreakJumpTarget);
2246 // Create an empty block to represent the transition block for looping back
2247 // to the head of the loop.
2248 Succ = TransitionBlock = createBlock(false);
2249 TransitionBlock->setLoopTarget(W);
2250 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos);
2252 // All breaks should go to the code following the loop.
2253 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
2255 // Loop body should end with destructor of Condition variable (if any).
2256 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W);
2258 // If body is not a compound statement create implicit scope
2259 // and add destructors.
2260 if (!isa<CompoundStmt>(W->getBody()))
2261 addLocalScopeAndDtors(W->getBody());
2263 // Create the body. The returned block is the entry to the loop body.
2264 BodyBlock = addStmt(W->getBody());
2267 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;"
2268 else if (Block && badCFG)
2272 // Because of short-circuit evaluation, the condition of the loop can span
2273 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
2274 // evaluate the condition.
2275 CFGBlock *EntryConditionBlock = 0, *ExitConditionBlock = 0;
2278 Expr *C = W->getCond();
2280 // Specially handle logical operators, which have a slightly
2281 // more optimal CFG representation.
2282 if (BinaryOperator *Cond = dyn_cast<BinaryOperator>(C->IgnoreParens()))
2283 if (Cond->isLogicalOp()) {
2284 llvm::tie(EntryConditionBlock, ExitConditionBlock) =
2285 VisitLogicalOperator(Cond, W, BodyBlock,
2290 // The default case when not handling logical operators.
2291 ExitConditionBlock = createBlock(false);
2292 ExitConditionBlock->setTerminator(W);
2294 // Now add the actual condition to the condition block.
2295 // Because the condition itself may contain control-flow, new blocks may
2296 // be created. Thus we update "Succ" after adding the condition.
2297 Block = ExitConditionBlock;
2298 Block = EntryConditionBlock = addStmt(C);
2300 // If this block contains a condition variable, add both the condition
2301 // variable and initializer to the CFG.
2302 if (VarDecl *VD = W->getConditionVariable()) {
2303 if (Expr *Init = VD->getInit()) {
2305 appendStmt(Block, W->getConditionVariableDeclStmt());
2306 EntryConditionBlock = addStmt(Init);
2307 assert(Block == EntryConditionBlock);
2311 if (Block && badCFG)
2314 // See if this is a known constant.
2315 const TryResult& KnownVal = tryEvaluateBool(C);
2317 // Add the loop body entry as a successor to the condition.
2318 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock);
2319 // Link up the condition block with the code that follows the loop. (the
2321 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor);
2325 // Link up the loop-back block to the entry condition block.
2326 addSuccessor(TransitionBlock, EntryConditionBlock);
2328 // There can be no more statements in the condition block since we loop back
2329 // to this block. NULL out Block to force lazy creation of another block.
2332 // Return the condition block, which is the dominating block for the loop.
2333 Succ = EntryConditionBlock;
2334 return EntryConditionBlock;
2338 CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) {
2339 // FIXME: For now we pretend that @catch and the code it contains does not
2344 CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) {
2345 // FIXME: This isn't complete. We basically treat @throw like a return
2348 // If we were in the middle of a block we stop processing that block.
2352 // Create the new block.
2353 Block = createBlock(false);
2355 // The Exit block is the only successor.
2356 addSuccessor(Block, &cfg->getExit());
2358 // Add the statement to the block. This may create new blocks if S contains
2359 // control-flow (short-circuit operations).
2360 return VisitStmt(S, AddStmtChoice::AlwaysAdd);
2363 CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) {
2364 // If we were in the middle of a block we stop processing that block.
2368 // Create the new block.
2369 Block = createBlock(false);
2371 if (TryTerminatedBlock)
2372 // The current try statement is the only successor.
2373 addSuccessor(Block, TryTerminatedBlock);
2375 // otherwise the Exit block is the only successor.
2376 addSuccessor(Block, &cfg->getExit());
2378 // Add the statement to the block. This may create new blocks if S contains
2379 // control-flow (short-circuit operations).
2380 return VisitStmt(T, AddStmtChoice::AlwaysAdd);
2383 CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) {
2384 CFGBlock *LoopSuccessor = NULL;
2386 // "do...while" is a control-flow statement. Thus we stop processing the
2391 LoopSuccessor = Block;
2393 LoopSuccessor = Succ;
2395 // Because of short-circuit evaluation, the condition of the loop can span
2396 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that
2397 // evaluate the condition.
2398 CFGBlock *ExitConditionBlock = createBlock(false);
2399 CFGBlock *EntryConditionBlock = ExitConditionBlock;
2401 // Set the terminator for the "exit" condition block.
2402 ExitConditionBlock->setTerminator(D);
2404 // Now add the actual condition to the condition block. Because the condition
2405 // itself may contain control-flow, new blocks may be created.
2406 if (Stmt *C = D->getCond()) {
2407 Block = ExitConditionBlock;
2408 EntryConditionBlock = addStmt(C);
2415 // The condition block is the implicit successor for the loop body.
2416 Succ = EntryConditionBlock;
2418 // See if this is a known constant.
2419 const TryResult &KnownVal = tryEvaluateBool(D->getCond());
2421 // Process the loop body.
2422 CFGBlock *BodyBlock = NULL;
2424 assert(D->getBody());
2426 // Save the current values for Block, Succ, and continue and break targets
2427 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
2428 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget),
2429 save_break(BreakJumpTarget);
2431 // All continues within this loop should go to the condition block
2432 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos);
2434 // All breaks should go to the code following the loop.
2435 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
2437 // NULL out Block to force lazy instantiation of blocks for the body.
2440 // If body is not a compound statement create implicit scope
2441 // and add destructors.
2442 if (!isa<CompoundStmt>(D->getBody()))
2443 addLocalScopeAndDtors(D->getBody());
2445 // Create the body. The returned block is the entry to the loop body.
2446 BodyBlock = addStmt(D->getBody());
2449 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)"
2455 if (!KnownVal.isFalse()) {
2456 // Add an intermediate block between the BodyBlock and the
2457 // ExitConditionBlock to represent the "loop back" transition. Create an
2458 // empty block to represent the transition block for looping back to the
2459 // head of the loop.
2460 // FIXME: Can we do this more efficiently without adding another block?
2463 CFGBlock *LoopBackBlock = createBlock();
2464 LoopBackBlock->setLoopTarget(D);
2466 // Add the loop body entry as a successor to the condition.
2467 addSuccessor(ExitConditionBlock, LoopBackBlock);
2470 addSuccessor(ExitConditionBlock, NULL);
2473 // Link up the condition block with the code that follows the loop.
2474 // (the false branch).
2475 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor);
2477 // There can be no more statements in the body block(s) since we loop back to
2478 // the body. NULL out Block to force lazy creation of another block.
2481 // Return the loop body, which is the dominating block for the loop.
2486 CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) {
2487 // "continue" is a control-flow statement. Thus we stop processing the
2492 // Now create a new block that ends with the continue statement.
2493 Block = createBlock(false);
2494 Block->setTerminator(C);
2496 // If there is no target for the continue, then we are looking at an
2497 // incomplete AST. This means the CFG cannot be constructed.
2498 if (ContinueJumpTarget.block) {
2499 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C);
2500 addSuccessor(Block, ContinueJumpTarget.block);
2507 CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E,
2508 AddStmtChoice asc) {
2510 if (asc.alwaysAdd(*this, E)) {
2512 appendStmt(Block, E);
2515 // VLA types have expressions that must be evaluated.
2516 CFGBlock *lastBlock = Block;
2518 if (E->isArgumentType()) {
2519 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr());
2520 VA != 0; VA = FindVA(VA->getElementType().getTypePtr()))
2521 lastBlock = addStmt(VA->getSizeExpr());
2526 /// VisitStmtExpr - Utility method to handle (nested) statement
2527 /// expressions (a GCC extension).
2528 CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) {
2529 if (asc.alwaysAdd(*this, SE)) {
2531 appendStmt(Block, SE);
2533 return VisitCompoundStmt(SE->getSubStmt());
2536 CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) {
2537 // "switch" is a control-flow statement. Thus we stop processing the current
2539 CFGBlock *SwitchSuccessor = NULL;
2541 // Save local scope position because in case of condition variable ScopePos
2542 // won't be restored when traversing AST.
2543 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2545 // Create local scope for possible condition variable.
2546 // Store scope position. Add implicit destructor.
2547 if (VarDecl *VD = Terminator->getConditionVariable()) {
2548 LocalScope::const_iterator SwitchBeginScopePos = ScopePos;
2549 addLocalScopeForVarDecl(VD);
2550 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator);
2556 SwitchSuccessor = Block;
2557 } else SwitchSuccessor = Succ;
2559 // Save the current "switch" context.
2560 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock),
2561 save_default(DefaultCaseBlock);
2562 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
2564 // Set the "default" case to be the block after the switch statement. If the
2565 // switch statement contains a "default:", this value will be overwritten with
2566 // the block for that code.
2567 DefaultCaseBlock = SwitchSuccessor;
2569 // Create a new block that will contain the switch statement.
2570 SwitchTerminatedBlock = createBlock(false);
2572 // Now process the switch body. The code after the switch is the implicit
2574 Succ = SwitchSuccessor;
2575 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos);
2577 // When visiting the body, the case statements should automatically get linked
2578 // up to the switch. We also don't keep a pointer to the body, since all
2579 // control-flow from the switch goes to case/default statements.
2580 assert(Terminator->getBody() && "switch must contain a non-NULL body");
2583 // For pruning unreachable case statements, save the current state
2584 // for tracking the condition value.
2585 SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered,
2588 // Determine if the switch condition can be explicitly evaluated.
2589 assert(Terminator->getCond() && "switch condition must be non-NULL");
2590 Expr::EvalResult result;
2591 bool b = tryEvaluate(Terminator->getCond(), result);
2592 SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond,
2595 // If body is not a compound statement create implicit scope
2596 // and add destructors.
2597 if (!isa<CompoundStmt>(Terminator->getBody()))
2598 addLocalScopeAndDtors(Terminator->getBody());
2600 addStmt(Terminator->getBody());
2606 // If we have no "default:" case, the default transition is to the code
2607 // following the switch body. Moreover, take into account if all the
2608 // cases of a switch are covered (e.g., switching on an enum value).
2609 addSuccessor(SwitchTerminatedBlock,
2610 switchExclusivelyCovered || Terminator->isAllEnumCasesCovered()
2611 ? 0 : DefaultCaseBlock);
2613 // Add the terminator and condition in the switch block.
2614 SwitchTerminatedBlock->setTerminator(Terminator);
2615 Block = SwitchTerminatedBlock;
2616 CFGBlock *LastBlock = addStmt(Terminator->getCond());
2618 // Finally, if the SwitchStmt contains a condition variable, add both the
2619 // SwitchStmt and the condition variable initialization to the CFG.
2620 if (VarDecl *VD = Terminator->getConditionVariable()) {
2621 if (Expr *Init = VD->getInit()) {
2623 appendStmt(Block, Terminator->getConditionVariableDeclStmt());
2624 LastBlock = addStmt(Init);
2631 static bool shouldAddCase(bool &switchExclusivelyCovered,
2632 const Expr::EvalResult *switchCond,
2638 bool addCase = false;
2640 if (!switchExclusivelyCovered) {
2641 if (switchCond->Val.isInt()) {
2642 // Evaluate the LHS of the case value.
2643 const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx);
2644 const llvm::APSInt &condInt = switchCond->Val.getInt();
2646 if (condInt == lhsInt) {
2648 switchExclusivelyCovered = true;
2650 else if (condInt < lhsInt) {
2651 if (const Expr *RHS = CS->getRHS()) {
2652 // Evaluate the RHS of the case value.
2653 const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx);
2654 if (V2 <= condInt) {
2656 switchExclusivelyCovered = true;
2667 CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) {
2668 // CaseStmts are essentially labels, so they are the first statement in a
2670 CFGBlock *TopBlock = 0, *LastBlock = 0;
2672 if (Stmt *Sub = CS->getSubStmt()) {
2673 // For deeply nested chains of CaseStmts, instead of doing a recursion
2674 // (which can blow out the stack), manually unroll and create blocks
2676 while (isa<CaseStmt>(Sub)) {
2677 CFGBlock *currentBlock = createBlock(false);
2678 currentBlock->setLabel(CS);
2681 addSuccessor(LastBlock, currentBlock);
2683 TopBlock = currentBlock;
2685 addSuccessor(SwitchTerminatedBlock,
2686 shouldAddCase(switchExclusivelyCovered, switchCond,
2688 ? currentBlock : 0);
2690 LastBlock = currentBlock;
2691 CS = cast<CaseStmt>(Sub);
2692 Sub = CS->getSubStmt();
2698 CFGBlock *CaseBlock = Block;
2700 CaseBlock = createBlock();
2702 // Cases statements partition blocks, so this is the top of the basic block we
2703 // were processing (the "case XXX:" is the label).
2704 CaseBlock->setLabel(CS);
2709 // Add this block to the list of successors for the block with the switch
2711 assert(SwitchTerminatedBlock);
2712 addSuccessor(SwitchTerminatedBlock,
2713 shouldAddCase(switchExclusivelyCovered, switchCond,
2717 // We set Block to NULL to allow lazy creation of a new block (if necessary)
2721 addSuccessor(LastBlock, CaseBlock);
2724 // This block is now the implicit successor of other blocks.
2731 CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) {
2732 if (Terminator->getSubStmt())
2733 addStmt(Terminator->getSubStmt());
2735 DefaultCaseBlock = Block;
2737 if (!DefaultCaseBlock)
2738 DefaultCaseBlock = createBlock();
2740 // Default statements partition blocks, so this is the top of the basic block
2741 // we were processing (the "default:" is the label).
2742 DefaultCaseBlock->setLabel(Terminator);
2747 // Unlike case statements, we don't add the default block to the successors
2748 // for the switch statement immediately. This is done when we finish
2749 // processing the switch statement. This allows for the default case
2750 // (including a fall-through to the code after the switch statement) to always
2751 // be the last successor of a switch-terminated block.
2753 // We set Block to NULL to allow lazy creation of a new block (if necessary)
2756 // This block is now the implicit successor of other blocks.
2757 Succ = DefaultCaseBlock;
2759 return DefaultCaseBlock;
2762 CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) {
2763 // "try"/"catch" is a control-flow statement. Thus we stop processing the
2765 CFGBlock *TrySuccessor = NULL;
2770 TrySuccessor = Block;
2771 } else TrySuccessor = Succ;
2773 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock;
2775 // Create a new block that will contain the try statement.
2776 CFGBlock *NewTryTerminatedBlock = createBlock(false);
2777 // Add the terminator in the try block.
2778 NewTryTerminatedBlock->setTerminator(Terminator);
2780 bool HasCatchAll = false;
2781 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) {
2782 // The code after the try is the implicit successor.
2783 Succ = TrySuccessor;
2784 CXXCatchStmt *CS = Terminator->getHandler(h);
2785 if (CS->getExceptionDecl() == 0) {
2789 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS);
2790 if (CatchBlock == 0)
2792 // Add this block to the list of successors for the block with the try
2794 addSuccessor(NewTryTerminatedBlock, CatchBlock);
2797 if (PrevTryTerminatedBlock)
2798 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock);
2800 addSuccessor(NewTryTerminatedBlock, &cfg->getExit());
2803 // The code after the try is the implicit successor.
2804 Succ = TrySuccessor;
2806 // Save the current "try" context.
2807 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock);
2808 cfg->addTryDispatchBlock(TryTerminatedBlock);
2810 assert(Terminator->getTryBlock() && "try must contain a non-NULL body");
2812 return addStmt(Terminator->getTryBlock());
2815 CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) {
2816 // CXXCatchStmt are treated like labels, so they are the first statement in a
2819 // Save local scope position because in case of exception variable ScopePos
2820 // won't be restored when traversing AST.
2821 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2823 // Create local scope for possible exception variable.
2824 // Store scope position. Add implicit destructor.
2825 if (VarDecl *VD = CS->getExceptionDecl()) {
2826 LocalScope::const_iterator BeginScopePos = ScopePos;
2827 addLocalScopeForVarDecl(VD);
2828 addAutomaticObjDtors(ScopePos, BeginScopePos, CS);
2831 if (CS->getHandlerBlock())
2832 addStmt(CS->getHandlerBlock());
2834 CFGBlock *CatchBlock = Block;
2836 CatchBlock = createBlock();
2838 // CXXCatchStmt is more than just a label. They have semantic meaning
2839 // as well, as they implicitly "initialize" the catch variable. Add
2840 // it to the CFG as a CFGElement so that the control-flow of these
2841 // semantics gets captured.
2842 appendStmt(CatchBlock, CS);
2844 // Also add the CXXCatchStmt as a label, to mirror handling of regular
2846 CatchBlock->setLabel(CS);
2848 // Bail out if the CFG is bad.
2852 // We set Block to NULL to allow lazy creation of a new block (if necessary)
2858 CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) {
2859 // C++0x for-range statements are specified as [stmt.ranged]:
2862 // auto && __range = range-init;
2863 // for ( auto __begin = begin-expr,
2864 // __end = end-expr;
2865 // __begin != __end;
2867 // for-range-declaration = *__begin;
2872 // Save local scope position before the addition of the implicit variables.
2873 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos);
2875 // Create local scopes and destructors for range, begin and end variables.
2876 if (Stmt *Range = S->getRangeStmt())
2877 addLocalScopeForStmt(Range);
2878 if (Stmt *BeginEnd = S->getBeginEndStmt())
2879 addLocalScopeForStmt(BeginEnd);
2880 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), S);
2882 LocalScope::const_iterator ContinueScopePos = ScopePos;
2884 // "for" is a control-flow statement. Thus we stop processing the current
2886 CFGBlock *LoopSuccessor = NULL;
2890 LoopSuccessor = Block;
2892 LoopSuccessor = Succ;
2894 // Save the current value for the break targets.
2895 // All breaks should go to the code following the loop.
2896 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget);
2897 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos);
2899 // The block for the __begin != __end expression.
2900 CFGBlock *ConditionBlock = createBlock(false);
2901 ConditionBlock->setTerminator(S);
2903 // Now add the actual condition to the condition block.
2904 if (Expr *C = S->getCond()) {
2905 Block = ConditionBlock;
2906 CFGBlock *BeginConditionBlock = addStmt(C);
2909 assert(BeginConditionBlock == ConditionBlock &&
2910 "condition block in for-range was unexpectedly complex");
2911 (void)BeginConditionBlock;
2914 // The condition block is the implicit successor for the loop body as well as
2915 // any code above the loop.
2916 Succ = ConditionBlock;
2918 // See if this is a known constant.
2919 TryResult KnownVal(true);
2922 KnownVal = tryEvaluateBool(S->getCond());
2924 // Now create the loop body.
2926 assert(S->getBody());
2928 // Save the current values for Block, Succ, and continue targets.
2929 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ);
2930 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget);
2932 // Generate increment code in its own basic block. This is the target of
2933 // continue statements.
2935 Succ = addStmt(S->getInc());
2936 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos);
2938 // The starting block for the loop increment is the block that should
2939 // represent the 'loop target' for looping back to the start of the loop.
2940 ContinueJumpTarget.block->setLoopTarget(S);
2942 // Finish up the increment block and prepare to start the loop body.
2949 // Add implicit scope and dtors for loop variable.
2950 addLocalScopeAndDtors(S->getLoopVarStmt());
2952 // Populate a new block to contain the loop body and loop variable.
2953 addStmt(S->getBody());
2956 CFGBlock *LoopVarStmtBlock = addStmt(S->getLoopVarStmt());
2960 // This new body block is a successor to our condition block.
2961 addSuccessor(ConditionBlock, KnownVal.isFalse() ? 0 : LoopVarStmtBlock);
2964 // Link up the condition block with the code that follows the loop (the
2966 addSuccessor(ConditionBlock, KnownVal.isTrue() ? 0 : LoopSuccessor);
2968 // Add the initialization statements.
2969 Block = createBlock();
2970 addStmt(S->getBeginEndStmt());
2971 return addStmt(S->getRangeStmt());
2974 CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E,
2975 AddStmtChoice asc) {
2976 if (BuildOpts.AddTemporaryDtors) {
2977 // If adding implicit destructors visit the full expression for adding
2978 // destructors of temporaries.
2979 VisitForTemporaryDtors(E->getSubExpr());
2981 // Full expression has to be added as CFGStmt so it will be sequenced
2982 // before destructors of it's temporaries.
2983 asc = asc.withAlwaysAdd(true);
2985 return Visit(E->getSubExpr(), asc);
2988 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E,
2989 AddStmtChoice asc) {
2990 if (asc.alwaysAdd(*this, E)) {
2992 appendStmt(Block, E);
2994 // We do not want to propagate the AlwaysAdd property.
2995 asc = asc.withAlwaysAdd(false);
2997 return Visit(E->getSubExpr(), asc);
3000 CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C,
3001 AddStmtChoice asc) {
3003 appendStmt(Block, C);
3005 return VisitChildren(C);
3008 CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
3009 AddStmtChoice asc) {
3010 if (asc.alwaysAdd(*this, E)) {
3012 appendStmt(Block, E);
3013 // We do not want to propagate the AlwaysAdd property.
3014 asc = asc.withAlwaysAdd(false);
3016 return Visit(E->getSubExpr(), asc);
3019 CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
3020 AddStmtChoice asc) {
3022 appendStmt(Block, C);
3023 return VisitChildren(C);
3026 CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E,
3027 AddStmtChoice asc) {
3028 if (asc.alwaysAdd(*this, E)) {
3030 appendStmt(Block, E);
3032 return Visit(E->getSubExpr(), AddStmtChoice());
3035 CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) {
3036 // Lazily create the indirect-goto dispatch block if there isn't one already.
3037 CFGBlock *IBlock = cfg->getIndirectGotoBlock();
3040 IBlock = createBlock(false);
3041 cfg->setIndirectGotoBlock(IBlock);
3044 // IndirectGoto is a control-flow statement. Thus we stop processing the
3045 // current block and create a new one.
3049 Block = createBlock(false);
3050 Block->setTerminator(I);
3051 addSuccessor(Block, IBlock);
3052 return addStmt(I->getTarget());
3055 CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) {
3056 assert(BuildOpts.AddImplicitDtors && BuildOpts.AddTemporaryDtors);
3063 switch (E->getStmtClass()) {
3065 return VisitChildrenForTemporaryDtors(E);
3067 case Stmt::BinaryOperatorClass:
3068 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E));
3070 case Stmt::CXXBindTemporaryExprClass:
3071 return VisitCXXBindTemporaryExprForTemporaryDtors(
3072 cast<CXXBindTemporaryExpr>(E), BindToTemporary);
3074 case Stmt::BinaryConditionalOperatorClass:
3075 case Stmt::ConditionalOperatorClass:
3076 return VisitConditionalOperatorForTemporaryDtors(
3077 cast<AbstractConditionalOperator>(E), BindToTemporary);
3079 case Stmt::ImplicitCastExprClass:
3080 // For implicit cast we want BindToTemporary to be passed further.
3081 E = cast<CastExpr>(E)->getSubExpr();
3084 case Stmt::ParenExprClass:
3085 E = cast<ParenExpr>(E)->getSubExpr();
3088 case Stmt::MaterializeTemporaryExprClass:
3089 E = cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr();
3094 CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) {
3095 // When visiting children for destructors we want to visit them in reverse
3096 // order. Because there's no reverse iterator for children must to reverse
3097 // them in helper vector.
3098 typedef SmallVector<Stmt *, 4> ChildrenVect;
3099 ChildrenVect ChildrenRev;
3100 for (Stmt::child_range I = E->children(); I; ++I) {
3101 if (*I) ChildrenRev.push_back(*I);
3104 CFGBlock *B = Block;
3105 for (ChildrenVect::reverse_iterator I = ChildrenRev.rbegin(),
3106 L = ChildrenRev.rend(); I != L; ++I) {
3107 if (CFGBlock *R = VisitForTemporaryDtors(*I))
3113 CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) {
3114 if (E->isLogicalOp()) {
3115 // Destructors for temporaries in LHS expression should be called after
3116 // those for RHS expression. Even if this will unnecessarily create a block,
3117 // this block will be used at least by the full expression.
3119 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS());
3123 Succ = ConfluenceBlock;
3125 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS());
3131 // If RHS expression did produce destructors we need to connect created
3132 // blocks to CFG in same manner as for binary operator itself.
3133 CFGBlock *LHSBlock = createBlock(false);
3134 LHSBlock->setTerminator(CFGTerminator(E, true));
3136 // For binary operator LHS block is before RHS in list of predecessors
3137 // of ConfluenceBlock.
3138 std::reverse(ConfluenceBlock->pred_begin(),
3139 ConfluenceBlock->pred_end());
3141 // See if this is a known constant.
3142 TryResult KnownVal = tryEvaluateBool(E->getLHS());
3143 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr))
3146 // Link LHSBlock with RHSBlock exactly the same way as for binary operator
3148 if (E->getOpcode() == BO_LOr) {
3149 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock);
3150 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock);
3152 assert (E->getOpcode() == BO_LAnd);
3153 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock);
3154 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock);
3161 Block = ConfluenceBlock;
3162 return ConfluenceBlock;
3165 if (E->isAssignmentOp()) {
3166 // For assignment operator (=) LHS expression is visited
3167 // before RHS expression. For destructors visit them in reverse order.
3168 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS());
3169 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS());
3170 return LHSBlock ? LHSBlock : RHSBlock;
3173 // For any other binary operator RHS expression is visited before
3174 // LHS expression (order of children). For destructors visit them in reverse
3176 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS());
3177 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS());
3178 return RHSBlock ? RHSBlock : LHSBlock;
3181 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors(
3182 CXXBindTemporaryExpr *E, bool BindToTemporary) {
3183 // First add destructors for temporaries in subexpression.
3184 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr());
3185 if (!BindToTemporary) {
3186 // If lifetime of temporary is not prolonged (by assigning to constant
3187 // reference) add destructor for it.
3189 // If the destructor is marked as a no-return destructor, we need to create
3190 // a new block for the destructor which does not have as a successor
3191 // anything built thus far. Control won't flow out of this block.
3192 const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor();
3193 if (cast<FunctionType>(Dtor->getType())->getNoReturnAttr())
3194 Block = createNoReturnBlock();
3198 appendTemporaryDtor(Block, E);
3204 CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors(
3205 AbstractConditionalOperator *E, bool BindToTemporary) {
3206 // First add destructors for condition expression. Even if this will
3207 // unnecessarily create a block, this block will be used at least by the full
3210 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond());
3213 if (BinaryConditionalOperator *BCO
3214 = dyn_cast<BinaryConditionalOperator>(E)) {
3215 ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon());
3220 // Try to add block with destructors for LHS expression.
3221 CFGBlock *LHSBlock = NULL;
3222 Succ = ConfluenceBlock;
3224 LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary);
3228 // Try to add block with destructors for RHS expression;
3229 Succ = ConfluenceBlock;
3231 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(),
3236 if (!RHSBlock && !LHSBlock) {
3237 // If neither LHS nor RHS expression had temporaries to destroy don't create
3239 Block = ConfluenceBlock;
3243 Block = createBlock(false);
3244 Block->setTerminator(CFGTerminator(E, true));
3246 // See if this is a known constant.
3247 const TryResult &KnownVal = tryEvaluateBool(E->getCond());
3250 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock);
3251 } else if (KnownVal.isFalse()) {
3252 addSuccessor(Block, NULL);
3254 addSuccessor(Block, ConfluenceBlock);
3255 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end());
3259 RHSBlock = ConfluenceBlock;
3260 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock);
3265 } // end anonymous namespace
3267 /// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has
3268 /// no successors or predecessors. If this is the first block created in the
3269 /// CFG, it is automatically set to be the Entry and Exit of the CFG.
3270 CFGBlock *CFG::createBlock() {
3271 bool first_block = begin() == end();
3273 // Create the block.
3274 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>();
3275 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this);
3276 Blocks.push_back(Mem, BlkBVC);
3278 // If this is the first block, set it as the Entry and Exit.
3280 Entry = Exit = &back();
3282 // Return the block.
3286 /// buildCFG - Constructs a CFG from an AST. Ownership of the returned
3287 /// CFG is returned to the caller.
3288 CFG* CFG::buildCFG(const Decl *D, Stmt *Statement, ASTContext *C,
3289 const BuildOptions &BO) {
3290 CFGBuilder Builder(C, BO);
3291 return Builder.buildCFG(D, Statement);
3294 const CXXDestructorDecl *
3295 CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const {
3296 switch (getKind()) {
3297 case CFGElement::Invalid:
3298 case CFGElement::Statement:
3299 case CFGElement::Initializer:
3300 llvm_unreachable("getDestructorDecl should only be used with "
3302 case CFGElement::AutomaticObjectDtor: {
3303 const VarDecl *var = cast<CFGAutomaticObjDtor>(this)->getVarDecl();
3304 QualType ty = var->getType();
3305 ty = ty.getNonReferenceType();
3306 while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) {
3307 ty = arrayType->getElementType();
3309 const RecordType *recordType = ty->getAs<RecordType>();
3310 const CXXRecordDecl *classDecl =
3311 cast<CXXRecordDecl>(recordType->getDecl());
3312 return classDecl->getDestructor();
3314 case CFGElement::TemporaryDtor: {
3315 const CXXBindTemporaryExpr *bindExpr =
3316 cast<CFGTemporaryDtor>(this)->getBindTemporaryExpr();
3317 const CXXTemporary *temp = bindExpr->getTemporary();
3318 return temp->getDestructor();
3320 case CFGElement::BaseDtor:
3321 case CFGElement::MemberDtor:
3323 // Not yet supported.
3326 llvm_unreachable("getKind() returned bogus value");
3329 bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const {
3330 if (const CXXDestructorDecl *decl = getDestructorDecl(astContext)) {
3331 QualType ty = decl->getType();
3332 return cast<FunctionType>(ty)->getNoReturnAttr();
3337 //===----------------------------------------------------------------------===//
3338 // CFG: Queries for BlkExprs.
3339 //===----------------------------------------------------------------------===//
3342 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy;
3345 static void FindSubExprAssignments(const Stmt *S,
3346 llvm::SmallPtrSet<const Expr*,50>& Set) {
3350 for (Stmt::const_child_range I = S->children(); I; ++I) {
3351 const Stmt *child = *I;
3355 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(child))
3356 if (B->isAssignmentOp()) Set.insert(B);
3358 FindSubExprAssignments(child, Set);
3362 static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) {
3363 BlkExprMapTy* M = new BlkExprMapTy();
3365 // Look for assignments that are used as subexpressions. These are the only
3366 // assignments that we want to *possibly* register as a block-level
3367 // expression. Basically, if an assignment occurs both in a subexpression and
3368 // at the block-level, it is a block-level expression.
3369 llvm::SmallPtrSet<const Expr*,50> SubExprAssignments;
3371 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I)
3372 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI)
3373 if (const CFGStmt *S = BI->getAs<CFGStmt>())
3374 FindSubExprAssignments(S->getStmt(), SubExprAssignments);
3376 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) {
3378 // Iterate over the statements again on identify the Expr* and Stmt* at the
3379 // block-level that are block-level expressions.
3381 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) {
3382 const CFGStmt *CS = BI->getAs<CFGStmt>();
3385 if (const Expr *Exp = dyn_cast<Expr>(CS->getStmt())) {
3386 assert((Exp->IgnoreParens() == Exp) && "No parens on block-level exps");
3388 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) {
3389 // Assignment expressions that are not nested within another
3390 // expression are really "statements" whose value is never used by
3391 // another expression.
3392 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp))
3394 } else if (const StmtExpr *SE = dyn_cast<StmtExpr>(Exp)) {
3395 // Special handling for statement expressions. The last statement in
3396 // the statement expression is also a block-level expr.
3397 const CompoundStmt *C = SE->getSubStmt();
3398 if (!C->body_empty()) {
3399 const Stmt *Last = C->body_back();
3400 if (const Expr *LastEx = dyn_cast<Expr>(Last))
3401 Last = LastEx->IgnoreParens();
3402 unsigned x = M->size();
3407 unsigned x = M->size();
3412 // Look at terminators. The condition is a block-level expression.
3414 Stmt *S = (*I)->getTerminatorCondition();
3416 if (S && M->find(S) == M->end()) {
3417 unsigned x = M->size();
3425 CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt *S) {
3427 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); }
3429 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap);
3430 BlkExprMapTy::iterator I = M->find(S);
3431 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second);
3434 unsigned CFG::getNumBlkExprs() {
3435 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap))
3438 // We assume callers interested in the number of BlkExprs will want
3439 // the map constructed if it doesn't already exist.
3440 BlkExprMap = (void*) PopulateBlkExprMap(*this);
3441 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size();
3444 //===----------------------------------------------------------------------===//
3445 // Filtered walking of the CFG.
3446 //===----------------------------------------------------------------------===//
3448 bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F,
3449 const CFGBlock *From, const CFGBlock *To) {
3451 if (To && F.IgnoreDefaultsWithCoveredEnums) {
3452 // If the 'To' has no label or is labeled but the label isn't a
3453 // CaseStmt then filter this edge.
3454 if (const SwitchStmt *S =
3455 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) {
3456 if (S->isAllEnumCasesCovered()) {
3457 const Stmt *L = To->getLabel();
3458 if (!L || !isa<CaseStmt>(L))
3467 //===----------------------------------------------------------------------===//
3468 // Cleanup: CFG dstor.
3469 //===----------------------------------------------------------------------===//
3472 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap);
3475 //===----------------------------------------------------------------------===//
3476 // CFG pretty printing
3477 //===----------------------------------------------------------------------===//
3481 class StmtPrinterHelper : public PrinterHelper {
3482 typedef llvm::DenseMap<const Stmt*,std::pair<unsigned,unsigned> > StmtMapTy;
3483 typedef llvm::DenseMap<const Decl*,std::pair<unsigned,unsigned> > DeclMapTy;
3486 signed currentBlock;
3488 const LangOptions &LangOpts;
3491 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO)
3492 : currentBlock(0), currStmt(0), LangOpts(LO)
3494 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) {
3496 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ;
3497 BI != BEnd; ++BI, ++j ) {
3498 if (const CFGStmt *SE = BI->getAs<CFGStmt>()) {
3499 const Stmt *stmt= SE->getStmt();
3500 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j);
3503 switch (stmt->getStmtClass()) {
3504 case Stmt::DeclStmtClass:
3505 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P;
3507 case Stmt::IfStmtClass: {
3508 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable();
3513 case Stmt::ForStmtClass: {
3514 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable();
3519 case Stmt::WhileStmtClass: {
3520 const VarDecl *var =
3521 cast<WhileStmt>(stmt)->getConditionVariable();
3526 case Stmt::SwitchStmtClass: {
3527 const VarDecl *var =
3528 cast<SwitchStmt>(stmt)->getConditionVariable();
3533 case Stmt::CXXCatchStmtClass: {
3534 const VarDecl *var =
3535 cast<CXXCatchStmt>(stmt)->getExceptionDecl();
3549 virtual ~StmtPrinterHelper() {}
3551 const LangOptions &getLangOpts() const { return LangOpts; }
3552 void setBlockID(signed i) { currentBlock = i; }
3553 void setStmtID(unsigned i) { currStmt = i; }
3555 virtual bool handledStmt(Stmt *S, raw_ostream &OS) {
3556 StmtMapTy::iterator I = StmtMap.find(S);
3558 if (I == StmtMap.end())
3561 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
3562 && I->second.second == currStmt) {
3566 OS << "[B" << I->second.first << "." << I->second.second << "]";
3570 bool handleDecl(const Decl *D, raw_ostream &OS) {
3571 DeclMapTy::iterator I = DeclMap.find(D);
3573 if (I == DeclMap.end())
3576 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock
3577 && I->second.second == currStmt) {
3581 OS << "[B" << I->second.first << "." << I->second.second << "]";
3585 } // end anonymous namespace
3589 class CFGBlockTerminatorPrint
3590 : public StmtVisitor<CFGBlockTerminatorPrint,void> {
3593 StmtPrinterHelper* Helper;
3594 PrintingPolicy Policy;
3596 CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper,
3597 const PrintingPolicy &Policy)
3598 : OS(os), Helper(helper), Policy(Policy) {}
3600 void VisitIfStmt(IfStmt *I) {
3602 I->getCond()->printPretty(OS,Helper,Policy);
3606 void VisitStmt(Stmt *Terminator) {
3607 Terminator->printPretty(OS, Helper, Policy);
3610 void VisitForStmt(ForStmt *F) {
3615 if (Stmt *C = F->getCond())
3616 C->printPretty(OS, Helper, Policy);
3623 void VisitWhileStmt(WhileStmt *W) {
3625 if (Stmt *C = W->getCond())
3626 C->printPretty(OS, Helper, Policy);
3629 void VisitDoStmt(DoStmt *D) {
3630 OS << "do ... while ";
3631 if (Stmt *C = D->getCond())
3632 C->printPretty(OS, Helper, Policy);
3635 void VisitSwitchStmt(SwitchStmt *Terminator) {
3637 Terminator->getCond()->printPretty(OS, Helper, Policy);
3640 void VisitCXXTryStmt(CXXTryStmt *CS) {
3644 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) {
3645 C->getCond()->printPretty(OS, Helper, Policy);
3646 OS << " ? ... : ...";
3649 void VisitChooseExpr(ChooseExpr *C) {
3650 OS << "__builtin_choose_expr( ";
3651 C->getCond()->printPretty(OS, Helper, Policy);
3655 void VisitIndirectGotoStmt(IndirectGotoStmt *I) {
3657 I->getTarget()->printPretty(OS, Helper, Policy);
3660 void VisitBinaryOperator(BinaryOperator* B) {
3661 if (!B->isLogicalOp()) {
3666 B->getLHS()->printPretty(OS, Helper, Policy);
3668 switch (B->getOpcode()) {
3676 llvm_unreachable("Invalid logical operator.");
3680 void VisitExpr(Expr *E) {
3681 E->printPretty(OS, Helper, Policy);
3684 } // end anonymous namespace
3686 static void print_elem(raw_ostream &OS, StmtPrinterHelper* Helper,
3687 const CFGElement &E) {
3688 if (const CFGStmt *CS = E.getAs<CFGStmt>()) {
3689 const Stmt *S = CS->getStmt();
3693 // special printing for statement-expressions.
3694 if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) {
3695 const CompoundStmt *Sub = SE->getSubStmt();
3697 if (Sub->children()) {
3699 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS);
3704 // special printing for comma expressions.
3705 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) {
3706 if (B->getOpcode() == BO_Comma) {
3708 Helper->handledStmt(B->getRHS(),OS);
3714 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts()));
3716 if (isa<CXXOperatorCallExpr>(S)) {
3717 OS << " (OperatorCall)";
3719 else if (isa<CXXBindTemporaryExpr>(S)) {
3720 OS << " (BindTemporary)";
3722 else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) {
3723 OS << " (CXXConstructExpr, " << CCE->getType().getAsString() << ")";
3725 else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) {
3726 OS << " (" << CE->getStmtClassName() << ", "
3727 << CE->getCastKindName()
3728 << ", " << CE->getType().getAsString()
3732 // Expressions need a newline.
3736 } else if (const CFGInitializer *IE = E.getAs<CFGInitializer>()) {
3737 const CXXCtorInitializer *I = IE->getInitializer();
3738 if (I->isBaseInitializer())
3739 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName();
3740 else OS << I->getAnyMember()->getName();
3743 if (Expr *IE = I->getInit())
3744 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts()));
3747 if (I->isBaseInitializer())
3748 OS << " (Base initializer)\n";
3749 else OS << " (Member initializer)\n";
3751 } else if (const CFGAutomaticObjDtor *DE = E.getAs<CFGAutomaticObjDtor>()){
3752 const VarDecl *VD = DE->getVarDecl();
3753 Helper->handleDecl(VD, OS);
3755 const Type* T = VD->getType().getTypePtr();
3756 if (const ReferenceType* RT = T->getAs<ReferenceType>())
3757 T = RT->getPointeeType().getTypePtr();
3758 T = T->getBaseElementTypeUnsafe();
3760 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()";
3761 OS << " (Implicit destructor)\n";
3763 } else if (const CFGBaseDtor *BE = E.getAs<CFGBaseDtor>()) {
3764 const CXXBaseSpecifier *BS = BE->getBaseSpecifier();
3765 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()";
3766 OS << " (Base object destructor)\n";
3768 } else if (const CFGMemberDtor *ME = E.getAs<CFGMemberDtor>()) {
3769 const FieldDecl *FD = ME->getFieldDecl();
3770 const Type *T = FD->getType()->getBaseElementTypeUnsafe();
3771 OS << "this->" << FD->getName();
3772 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()";
3773 OS << " (Member object destructor)\n";
3775 } else if (const CFGTemporaryDtor *TE = E.getAs<CFGTemporaryDtor>()) {
3776 const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr();
3777 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()";
3778 OS << " (Temporary object destructor)\n";
3782 static void print_block(raw_ostream &OS, const CFG* cfg,
3784 StmtPrinterHelper* Helper, bool print_edges,
3788 Helper->setBlockID(B.getBlockID());
3790 // Print the header.
3792 OS.changeColor(raw_ostream::YELLOW, true);
3794 OS << "\n [B" << B.getBlockID();
3796 if (&B == &cfg->getEntry())
3797 OS << " (ENTRY)]\n";
3798 else if (&B == &cfg->getExit())
3800 else if (&B == cfg->getIndirectGotoBlock())
3801 OS << " (INDIRECT GOTO DISPATCH)]\n";
3808 // Print the label of this block.
3809 if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) {
3814 if (LabelStmt *L = dyn_cast<LabelStmt>(Label))
3816 else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) {
3818 C->getLHS()->printPretty(OS, Helper,
3819 PrintingPolicy(Helper->getLangOpts()));
3822 C->getRHS()->printPretty(OS, Helper,
3823 PrintingPolicy(Helper->getLangOpts()));
3825 } else if (isa<DefaultStmt>(Label))
3827 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) {
3829 if (CS->getExceptionDecl())
3830 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()),
3837 llvm_unreachable("Invalid label statement in CFGBlock.");
3842 // Iterate through the statements in the block and print them.
3845 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ;
3846 I != E ; ++I, ++j ) {
3848 // Print the statement # in the basic block and the statement itself.
3852 OS << llvm::format("%3d", j) << ": ";
3855 Helper->setStmtID(j);
3857 print_elem(OS, Helper, *I);
3860 // Print the terminator of this block.
3861 if (B.getTerminator()) {
3863 OS.changeColor(raw_ostream::GREEN);
3867 if (Helper) Helper->setBlockID(-1);
3869 PrintingPolicy PP(Helper ? Helper->getLangOpts() : LangOptions());
3870 CFGBlockTerminatorPrint TPrinter(OS, Helper, PP);
3871 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt()));
3879 // Print the predecessors of this block.
3880 if (!B.pred_empty()) {
3881 const raw_ostream::Colors Color = raw_ostream::BLUE;
3883 OS.changeColor(Color);
3887 OS << '(' << B.pred_size() << "):";
3891 OS.changeColor(Color);
3893 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end();
3896 if (i == 8 || (i-8) == 0)
3899 OS << " B" << (*I)->getBlockID();
3908 // Print the successors of this block.
3909 if (!B.succ_empty()) {
3910 const raw_ostream::Colors Color = raw_ostream::MAGENTA;
3912 OS.changeColor(Color);
3916 OS << '(' << B.succ_size() << "):";
3920 OS.changeColor(Color);
3922 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end();
3925 if (i == 8 || (i-8) % 10 == 0)
3929 OS << " B" << (*I)->getBlockID();
3942 /// dump - A simple pretty printer of a CFG that outputs to stderr.
3943 void CFG::dump(const LangOptions &LO, bool ShowColors) const {
3944 print(llvm::errs(), LO, ShowColors);
3947 /// print - A simple pretty printer of a CFG that outputs to an ostream.
3948 void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const {
3949 StmtPrinterHelper Helper(this, LO);
3951 // Print the entry block.
3952 print_block(OS, this, getEntry(), &Helper, true, ShowColors);
3954 // Iterate through the CFGBlocks and print them one by one.
3955 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) {
3956 // Skip the entry block, because we already printed it.
3957 if (&(**I) == &getEntry() || &(**I) == &getExit())
3960 print_block(OS, this, **I, &Helper, true, ShowColors);
3963 // Print the exit block.
3964 print_block(OS, this, getExit(), &Helper, true, ShowColors);
3969 /// dump - A simply pretty printer of a CFGBlock that outputs to stderr.
3970 void CFGBlock::dump(const CFG* cfg, const LangOptions &LO,
3971 bool ShowColors) const {
3972 print(llvm::errs(), cfg, LO, ShowColors);
3975 /// print - A simple pretty printer of a CFGBlock that outputs to an ostream.
3976 /// Generally this will only be called from CFG::print.
3977 void CFGBlock::print(raw_ostream &OS, const CFG* cfg,
3978 const LangOptions &LO, bool ShowColors) const {
3979 StmtPrinterHelper Helper(cfg, LO);
3980 print_block(OS, cfg, *this, &Helper, true, ShowColors);
3984 /// printTerminator - A simple pretty printer of the terminator of a CFGBlock.
3985 void CFGBlock::printTerminator(raw_ostream &OS,
3986 const LangOptions &LO) const {
3987 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO));
3988 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt()));
3991 Stmt *CFGBlock::getTerminatorCondition() {
3992 Stmt *Terminator = this->Terminator;
3998 switch (Terminator->getStmtClass()) {
4002 case Stmt::ForStmtClass:
4003 E = cast<ForStmt>(Terminator)->getCond();
4006 case Stmt::WhileStmtClass:
4007 E = cast<WhileStmt>(Terminator)->getCond();
4010 case Stmt::DoStmtClass:
4011 E = cast<DoStmt>(Terminator)->getCond();
4014 case Stmt::IfStmtClass:
4015 E = cast<IfStmt>(Terminator)->getCond();
4018 case Stmt::ChooseExprClass:
4019 E = cast<ChooseExpr>(Terminator)->getCond();
4022 case Stmt::IndirectGotoStmtClass:
4023 E = cast<IndirectGotoStmt>(Terminator)->getTarget();
4026 case Stmt::SwitchStmtClass:
4027 E = cast<SwitchStmt>(Terminator)->getCond();
4030 case Stmt::BinaryConditionalOperatorClass:
4031 E = cast<BinaryConditionalOperator>(Terminator)->getCond();
4034 case Stmt::ConditionalOperatorClass:
4035 E = cast<ConditionalOperator>(Terminator)->getCond();
4038 case Stmt::BinaryOperatorClass: // '&&' and '||'
4039 E = cast<BinaryOperator>(Terminator)->getLHS();
4042 case Stmt::ObjCForCollectionStmtClass:
4046 return E ? E->IgnoreParens() : NULL;
4049 //===----------------------------------------------------------------------===//
4050 // CFG Graphviz Visualization
4051 //===----------------------------------------------------------------------===//
4055 static StmtPrinterHelper* GraphHelper;
4058 void CFG::viewCFG(const LangOptions &LO) const {
4060 StmtPrinterHelper H(this, LO);
4062 llvm::ViewGraph(this,"CFG");
4069 struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits {
4071 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
4073 static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) {
4076 std::string OutSStr;
4077 llvm::raw_string_ostream Out(OutSStr);
4078 print_block(Out,Graph, *Node, GraphHelper, false, false);
4079 std::string& OutStr = Out.str();
4081 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
4083 // Process string output to make it nicer...
4084 for (unsigned i = 0; i != OutStr.length(); ++i)
4085 if (OutStr[i] == '\n') { // Left justify
4087 OutStr.insert(OutStr.begin()+i+1, 'l');
4096 } // end namespace llvm