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Diffstat (limited to 'contrib/llvm/tools/clang/lib/Analysis/CFG.cpp')
| -rw-r--r-- | contrib/llvm/tools/clang/lib/Analysis/CFG.cpp | 3407 |
1 files changed, 3407 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/Analysis/CFG.cpp b/contrib/llvm/tools/clang/lib/Analysis/CFG.cpp new file mode 100644 index 0000000..a0ec5fe --- /dev/null +++ b/contrib/llvm/tools/clang/lib/Analysis/CFG.cpp @@ -0,0 +1,3407 @@ +//===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file defines the CFG and CFGBuilder classes for representing and +// building Control-Flow Graphs (CFGs) from ASTs. +// +//===----------------------------------------------------------------------===// + +#include "clang/Analysis/Support/SaveAndRestore.h" +#include "clang/Analysis/CFG.h" +#include "clang/AST/DeclCXX.h" +#include "clang/AST/StmtVisitor.h" +#include "clang/AST/PrettyPrinter.h" +#include "llvm/Support/GraphWriter.h" +#include "llvm/Support/Allocator.h" +#include "llvm/Support/Format.h" +#include "llvm/ADT/DenseMap.h" +#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/ADT/OwningPtr.h" + +using namespace clang; + +namespace { + +static SourceLocation GetEndLoc(Decl* D) { + if (VarDecl* VD = dyn_cast<VarDecl>(D)) + if (Expr* Ex = VD->getInit()) + return Ex->getSourceRange().getEnd(); + return D->getLocation(); +} + +/// The CFG builder uses a recursive algorithm to build the CFG. When +/// we process an expression, sometimes we know that we must add the +/// subexpressions as block-level expressions. For example: +/// +/// exp1 || exp2 +/// +/// When processing the '||' expression, we know that exp1 and exp2 +/// need to be added as block-level expressions, even though they +/// might not normally need to be. AddStmtChoice records this +/// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then +/// the builder has an option not to add a subexpression as a +/// block-level expression. +/// +class AddStmtChoice { +public: + enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 }; + + AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {} + + bool alwaysAdd() const { return kind & AlwaysAdd; } + + /// Return a copy of this object, except with the 'always-add' bit + /// set as specified. + AddStmtChoice withAlwaysAdd(bool alwaysAdd) const { + return AddStmtChoice(alwaysAdd ? Kind(kind | AlwaysAdd) : + Kind(kind & ~AlwaysAdd)); + } + +private: + Kind kind; +}; + +/// LocalScope - Node in tree of local scopes created for C++ implicit +/// destructor calls generation. It contains list of automatic variables +/// declared in the scope and link to position in previous scope this scope +/// began in. +/// +/// The process of creating local scopes is as follows: +/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), +/// - Before processing statements in scope (e.g. CompoundStmt) create +/// LocalScope object using CFGBuilder::ScopePos as link to previous scope +/// and set CFGBuilder::ScopePos to the end of new scope, +/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points +/// at this VarDecl, +/// - For every normal (without jump) end of scope add to CFGBlock destructors +/// for objects in the current scope, +/// - For every jump add to CFGBlock destructors for objects +/// between CFGBuilder::ScopePos and local scope position saved for jump +/// target. Thanks to C++ restrictions on goto jumps we can be sure that +/// jump target position will be on the path to root from CFGBuilder::ScopePos +/// (adding any variable that doesn't need constructor to be called to +/// LocalScope can break this assumption), +/// +class LocalScope { +public: + typedef BumpVector<VarDecl*> AutomaticVarsTy; + + /// const_iterator - Iterates local scope backwards and jumps to previous + /// scope on reaching the beginning of currently iterated scope. + class const_iterator { + const LocalScope* Scope; + + /// VarIter is guaranteed to be greater then 0 for every valid iterator. + /// Invalid iterator (with null Scope) has VarIter equal to 0. + unsigned VarIter; + + public: + /// Create invalid iterator. Dereferencing invalid iterator is not allowed. + /// Incrementing invalid iterator is allowed and will result in invalid + /// iterator. + const_iterator() + : Scope(NULL), VarIter(0) {} + + /// Create valid iterator. In case when S.Prev is an invalid iterator and + /// I is equal to 0, this will create invalid iterator. + const_iterator(const LocalScope& S, unsigned I) + : Scope(&S), VarIter(I) { + // Iterator to "end" of scope is not allowed. Handle it by going up + // in scopes tree possibly up to invalid iterator in the root. + if (VarIter == 0 && Scope) + *this = Scope->Prev; + } + + VarDecl* const* operator->() const { + assert (Scope && "Dereferencing invalid iterator is not allowed"); + assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); + return &Scope->Vars[VarIter - 1]; + } + VarDecl* operator*() const { + return *this->operator->(); + } + + const_iterator& operator++() { + if (!Scope) + return *this; + + assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); + --VarIter; + if (VarIter == 0) + *this = Scope->Prev; + return *this; + } + const_iterator operator++(int) { + const_iterator P = *this; + ++*this; + return P; + } + + bool operator==(const const_iterator& rhs) const { + return Scope == rhs.Scope && VarIter == rhs.VarIter; + } + bool operator!=(const const_iterator& rhs) const { + return !(*this == rhs); + } + + operator bool() const { + return *this != const_iterator(); + } + + int distance(const_iterator L); + }; + + friend class const_iterator; + +private: + BumpVectorContext ctx; + + /// Automatic variables in order of declaration. + AutomaticVarsTy Vars; + /// Iterator to variable in previous scope that was declared just before + /// begin of this scope. + const_iterator Prev; + +public: + /// Constructs empty scope linked to previous scope in specified place. + LocalScope(BumpVectorContext &ctx, const_iterator P) + : ctx(ctx), Vars(ctx, 4), Prev(P) {} + + /// Begin of scope in direction of CFG building (backwards). + const_iterator begin() const { return const_iterator(*this, Vars.size()); } + + void addVar(VarDecl* VD) { + Vars.push_back(VD, ctx); + } +}; + +/// distance - Calculates distance from this to L. L must be reachable from this +/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. +/// number of scopes between this and L. +int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { + int D = 0; + const_iterator F = *this; + while (F.Scope != L.Scope) { + assert (F != const_iterator() + && "L iterator is not reachable from F iterator."); + D += F.VarIter; + F = F.Scope->Prev; + } + D += F.VarIter - L.VarIter; + return D; +} + +/// BlockScopePosPair - Structure for specifying position in CFG during its +/// build process. It consists of CFGBlock that specifies position in CFG graph +/// and LocalScope::const_iterator that specifies position in LocalScope graph. +struct BlockScopePosPair { + BlockScopePosPair() : block(0) {} + BlockScopePosPair(CFGBlock* b, LocalScope::const_iterator scopePos) + : block(b), scopePosition(scopePos) {} + + CFGBlock *block; + LocalScope::const_iterator scopePosition; +}; + +/// CFGBuilder - This class implements CFG construction from an AST. +/// The builder is stateful: an instance of the builder should be used to only +/// construct a single CFG. +/// +/// Example usage: +/// +/// CFGBuilder builder; +/// CFG* cfg = builder.BuildAST(stmt1); +/// +/// CFG construction is done via a recursive walk of an AST. We actually parse +/// the AST in reverse order so that the successor of a basic block is +/// constructed prior to its predecessor. This allows us to nicely capture +/// implicit fall-throughs without extra basic blocks. +/// +class CFGBuilder { + typedef BlockScopePosPair JumpTarget; + typedef BlockScopePosPair JumpSource; + + ASTContext *Context; + llvm::OwningPtr<CFG> cfg; + + CFGBlock* Block; + CFGBlock* Succ; + JumpTarget ContinueJumpTarget; + JumpTarget BreakJumpTarget; + CFGBlock* SwitchTerminatedBlock; + CFGBlock* DefaultCaseBlock; + CFGBlock* TryTerminatedBlock; + + // Current position in local scope. + LocalScope::const_iterator ScopePos; + + // LabelMap records the mapping from Label expressions to their jump targets. + typedef llvm::DenseMap<LabelDecl*, JumpTarget> LabelMapTy; + LabelMapTy LabelMap; + + // A list of blocks that end with a "goto" that must be backpatched to their + // resolved targets upon completion of CFG construction. + typedef std::vector<JumpSource> BackpatchBlocksTy; + BackpatchBlocksTy BackpatchBlocks; + + // A list of labels whose address has been taken (for indirect gotos). + typedef llvm::SmallPtrSet<LabelDecl*, 5> LabelSetTy; + LabelSetTy AddressTakenLabels; + + bool badCFG; + CFG::BuildOptions BuildOpts; + +public: + explicit CFGBuilder() : cfg(new CFG()), // crew a new CFG + Block(NULL), Succ(NULL), + SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), + TryTerminatedBlock(NULL), badCFG(false) {} + + // buildCFG - Used by external clients to construct the CFG. + CFG* buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, + CFG::BuildOptions BO); + +private: + // Visitors to walk an AST and construct the CFG. + CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); + CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); + CFGBlock *VisitBlockExpr(BlockExpr* E, AddStmtChoice asc); + CFGBlock *VisitBreakStmt(BreakStmt *B); + CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); + CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, + AddStmtChoice asc); + CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); + CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); + CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, + AddStmtChoice asc); + CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc); + CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, + AddStmtChoice asc); + CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, + AddStmtChoice asc); + CFGBlock *VisitCXXMemberCallExpr(CXXMemberCallExpr *C, AddStmtChoice asc); + CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); + CFGBlock *VisitCaseStmt(CaseStmt *C); + CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); + CFGBlock *VisitCompoundStmt(CompoundStmt *C); + CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C, + AddStmtChoice asc); + CFGBlock *VisitContinueStmt(ContinueStmt *C); + CFGBlock *VisitDeclStmt(DeclStmt *DS); + CFGBlock *VisitDeclSubExpr(DeclStmt* DS); + CFGBlock *VisitDefaultStmt(DefaultStmt *D); + CFGBlock *VisitDoStmt(DoStmt *D); + CFGBlock *VisitForStmt(ForStmt *F); + CFGBlock *VisitGotoStmt(GotoStmt* G); + CFGBlock *VisitIfStmt(IfStmt *I); + CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc); + CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); + CFGBlock *VisitLabelStmt(LabelStmt *L); + CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); + CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); + CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); + CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); + CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); + CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); + CFGBlock *VisitReturnStmt(ReturnStmt* R); + CFGBlock *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, AddStmtChoice asc); + CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); + CFGBlock *VisitSwitchStmt(SwitchStmt *S); + CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc); + CFGBlock *VisitWhileStmt(WhileStmt *W); + + CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); + CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); + CFGBlock *VisitChildren(Stmt* S); + + // Visitors to walk an AST and generate destructors of temporaries in + // full expression. + CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false); + CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E); + CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E); + CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E, + bool BindToTemporary); + CFGBlock * + VisitConditionalOperatorForTemporaryDtors(AbstractConditionalOperator *E, + bool BindToTemporary); + + // NYS == Not Yet Supported + CFGBlock* NYS() { + badCFG = true; + return Block; + } + + void autoCreateBlock() { if (!Block) Block = createBlock(); } + CFGBlock *createBlock(bool add_successor = true); + + CFGBlock *addStmt(Stmt *S) { + return Visit(S, AddStmtChoice::AlwaysAdd); + } + CFGBlock *addInitializer(CXXCtorInitializer *I); + void addAutomaticObjDtors(LocalScope::const_iterator B, + LocalScope::const_iterator E, Stmt* S); + void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); + + // Local scopes creation. + LocalScope* createOrReuseLocalScope(LocalScope* Scope); + + void addLocalScopeForStmt(Stmt* S); + LocalScope* addLocalScopeForDeclStmt(DeclStmt* DS, LocalScope* Scope = NULL); + LocalScope* addLocalScopeForVarDecl(VarDecl* VD, LocalScope* Scope = NULL); + + void addLocalScopeAndDtors(Stmt* S); + + // Interface to CFGBlock - adding CFGElements. + void appendStmt(CFGBlock *B, Stmt *S, + AddStmtChoice asc = AddStmtChoice::AlwaysAdd) { + B->appendStmt(S, cfg->getBumpVectorContext()); + } + void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) { + B->appendInitializer(I, cfg->getBumpVectorContext()); + } + void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { + B->appendBaseDtor(BS, cfg->getBumpVectorContext()); + } + void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { + B->appendMemberDtor(FD, cfg->getBumpVectorContext()); + } + void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) { + B->appendTemporaryDtor(E, cfg->getBumpVectorContext()); + } + + void insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, + LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S); + void appendAutomaticObjDtors(CFGBlock* Blk, LocalScope::const_iterator B, + LocalScope::const_iterator E, Stmt* S); + void prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, + LocalScope::const_iterator B, LocalScope::const_iterator E); + + void addSuccessor(CFGBlock *B, CFGBlock *S) { + B->addSuccessor(S, cfg->getBumpVectorContext()); + } + + /// TryResult - a class representing a variant over the values + /// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool, + /// and is used by the CFGBuilder to decide if a branch condition + /// can be decided up front during CFG construction. + class TryResult { + int X; + public: + TryResult(bool b) : X(b ? 1 : 0) {} + TryResult() : X(-1) {} + + bool isTrue() const { return X == 1; } + bool isFalse() const { return X == 0; } + bool isKnown() const { return X >= 0; } + void negate() { + assert(isKnown()); + X ^= 0x1; + } + }; + + /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 + /// if we can evaluate to a known value, otherwise return -1. + TryResult tryEvaluateBool(Expr *S) { + if (!BuildOpts.PruneTriviallyFalseEdges) + return TryResult(); + + Expr::EvalResult Result; + if (!S->isTypeDependent() && !S->isValueDependent() && + S->Evaluate(Result, *Context) && Result.Val.isInt()) + return Result.Val.getInt().getBoolValue(); + + return TryResult(); + } +}; + +// FIXME: Add support for dependent-sized array types in C++? +// Does it even make sense to build a CFG for an uninstantiated template? +static const VariableArrayType *FindVA(const Type *t) { + while (const ArrayType *vt = dyn_cast<ArrayType>(t)) { + if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt)) + if (vat->getSizeExpr()) + return vat; + + t = vt->getElementType().getTypePtr(); + } + + return 0; +} + +/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an +/// arbitrary statement. Examples include a single expression or a function +/// body (compound statement). The ownership of the returned CFG is +/// transferred to the caller. If CFG construction fails, this method returns +/// NULL. +CFG* CFGBuilder::buildCFG(const Decl *D, Stmt* Statement, ASTContext* C, + CFG::BuildOptions BO) { + + Context = C; + assert(cfg.get()); + if (!Statement) + return NULL; + + BuildOpts = BO; + + // Create an empty block that will serve as the exit block for the CFG. Since + // this is the first block added to the CFG, it will be implicitly registered + // as the exit block. + Succ = createBlock(); + assert(Succ == &cfg->getExit()); + Block = NULL; // the EXIT block is empty. Create all other blocks lazily. + + if (BuildOpts.AddImplicitDtors) + if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) + addImplicitDtorsForDestructor(DD); + + // Visit the statements and create the CFG. + CFGBlock *B = addStmt(Statement); + + if (badCFG) + return NULL; + + // For C++ constructor add initializers to CFG. + if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { + for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), + E = CD->init_rend(); I != E; ++I) { + B = addInitializer(*I); + if (badCFG) + return NULL; + } + } + + if (B) + Succ = B; + + // Backpatch the gotos whose label -> block mappings we didn't know when we + // encountered them. + for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), + E = BackpatchBlocks.end(); I != E; ++I ) { + + CFGBlock* B = I->block; + GotoStmt* G = cast<GotoStmt>(B->getTerminator()); + LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); + + // If there is no target for the goto, then we are looking at an + // incomplete AST. Handle this by not registering a successor. + if (LI == LabelMap.end()) continue; + + JumpTarget JT = LI->second; + prependAutomaticObjDtorsWithTerminator(B, I->scopePosition, + JT.scopePosition); + addSuccessor(B, JT.block); + } + + // Add successors to the Indirect Goto Dispatch block (if we have one). + if (CFGBlock* B = cfg->getIndirectGotoBlock()) + for (LabelSetTy::iterator I = AddressTakenLabels.begin(), + E = AddressTakenLabels.end(); I != E; ++I ) { + + // Lookup the target block. + LabelMapTy::iterator LI = LabelMap.find(*I); + + // If there is no target block that contains label, then we are looking + // at an incomplete AST. Handle this by not registering a successor. + if (LI == LabelMap.end()) continue; + + addSuccessor(B, LI->second.block); + } + + // Create an empty entry block that has no predecessors. + cfg->setEntry(createBlock()); + + return cfg.take(); +} + +/// createBlock - Used to lazily create blocks that are connected +/// to the current (global) succcessor. +CFGBlock* CFGBuilder::createBlock(bool add_successor) { + CFGBlock* B = cfg->createBlock(); + if (add_successor && Succ) + addSuccessor(B, Succ); + return B; +} + +/// addInitializer - Add C++ base or member initializer element to CFG. +CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) { + if (!BuildOpts.AddInitializers) + return Block; + + bool IsReference = false; + bool HasTemporaries = false; + + // Destructors of temporaries in initialization expression should be called + // after initialization finishes. + Expr *Init = I->getInit(); + if (Init) { + if (FieldDecl *FD = I->getAnyMember()) + IsReference = FD->getType()->isReferenceType(); + HasTemporaries = isa<ExprWithCleanups>(Init); + + if (BuildOpts.AddImplicitDtors && HasTemporaries) { + // Generate destructors for temporaries in initialization expression. + VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), + IsReference); + } + } + + autoCreateBlock(); + appendInitializer(Block, I); + + if (Init) { + if (HasTemporaries) { + // For expression with temporaries go directly to subexpression to omit + // generating destructors for the second time. + return Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); + } + return Visit(Init); + } + + return Block; +} + +/// addAutomaticObjDtors - Add to current block automatic objects destructors +/// for objects in range of local scope positions. Use S as trigger statement +/// for destructors. +void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, + LocalScope::const_iterator E, Stmt* S) { + if (!BuildOpts.AddImplicitDtors) + return; + + if (B == E) + return; + + autoCreateBlock(); + appendAutomaticObjDtors(Block, B, E, S); +} + +/// addImplicitDtorsForDestructor - Add implicit destructors generated for +/// base and member objects in destructor. +void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { + assert (BuildOpts.AddImplicitDtors + && "Can be called only when dtors should be added"); + const CXXRecordDecl *RD = DD->getParent(); + + // At the end destroy virtual base objects. + for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), + VE = RD->vbases_end(); VI != VE; ++VI) { + const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); + if (!CD->hasTrivialDestructor()) { + autoCreateBlock(); + appendBaseDtor(Block, VI); + } + } + + // Before virtual bases destroy direct base objects. + for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), + BE = RD->bases_end(); BI != BE; ++BI) { + if (!BI->isVirtual()) { + const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); + if (!CD->hasTrivialDestructor()) { + autoCreateBlock(); + appendBaseDtor(Block, BI); + } + } + } + + // First destroy member objects. + for (CXXRecordDecl::field_iterator FI = RD->field_begin(), + FE = RD->field_end(); FI != FE; ++FI) { + // Check for constant size array. Set type to array element type. + QualType QT = FI->getType(); + if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { + if (AT->getSize() == 0) + continue; + QT = AT->getElementType(); + } + + if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) + if (!CD->hasTrivialDestructor()) { + autoCreateBlock(); + appendMemberDtor(Block, *FI); + } + } +} + +/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either +/// way return valid LocalScope object. +LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { + if (!Scope) { + llvm::BumpPtrAllocator &alloc = cfg->getAllocator(); + Scope = alloc.Allocate<LocalScope>(); + BumpVectorContext ctx(alloc); + new (Scope) LocalScope(ctx, ScopePos); + } + return Scope; +} + +/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement +/// that should create implicit scope (e.g. if/else substatements). +void CFGBuilder::addLocalScopeForStmt(Stmt* S) { + if (!BuildOpts.AddImplicitDtors) + return; + + LocalScope *Scope = 0; + + // For compound statement we will be creating explicit scope. + if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) { + for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() + ; BI != BE; ++BI) { + Stmt *SI = *BI; + if (LabelStmt *LS = dyn_cast<LabelStmt>(SI)) + SI = LS->getSubStmt(); + if (DeclStmt *DS = dyn_cast<DeclStmt>(SI)) + Scope = addLocalScopeForDeclStmt(DS, Scope); + } + return; + } + + // For any other statement scope will be implicit and as such will be + // interesting only for DeclStmt. + if (LabelStmt *LS = dyn_cast<LabelStmt>(S)) + S = LS->getSubStmt(); + if (DeclStmt *DS = dyn_cast<DeclStmt>(S)) + addLocalScopeForDeclStmt(DS); +} + +/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will +/// reuse Scope if not NULL. +LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt* DS, + LocalScope* Scope) { + if (!BuildOpts.AddImplicitDtors) + return Scope; + + for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() + ; DI != DE; ++DI) { + if (VarDecl* VD = dyn_cast<VarDecl>(*DI)) + Scope = addLocalScopeForVarDecl(VD, Scope); + } + return Scope; +} + +/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will +/// create add scope for automatic objects and temporary objects bound to +/// const reference. Will reuse Scope if not NULL. +LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl* VD, + LocalScope* Scope) { + if (!BuildOpts.AddImplicitDtors) + return Scope; + + // Check if variable is local. + switch (VD->getStorageClass()) { + case SC_None: + case SC_Auto: + case SC_Register: + break; + default: return Scope; + } + + // Check for const references bound to temporary. Set type to pointee. + QualType QT = VD->getType(); + if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { + QT = RT->getPointeeType(); + if (!QT.isConstQualified()) + return Scope; + if (!VD->getInit() || !VD->getInit()->Classify(*Context).isRValue()) + return Scope; + } + + // Check for constant size array. Set type to array element type. + if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { + if (AT->getSize() == 0) + return Scope; + QT = AT->getElementType(); + } + + // Check if type is a C++ class with non-trivial destructor. + if (const CXXRecordDecl* CD = QT->getAsCXXRecordDecl()) + if (!CD->hasTrivialDestructor()) { + // Add the variable to scope + Scope = createOrReuseLocalScope(Scope); + Scope->addVar(VD); + ScopePos = Scope->begin(); + } + return Scope; +} + +/// addLocalScopeAndDtors - For given statement add local scope for it and +/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. +void CFGBuilder::addLocalScopeAndDtors(Stmt* S) { + if (!BuildOpts.AddImplicitDtors) + return; + + LocalScope::const_iterator scopeBeginPos = ScopePos; + addLocalScopeForStmt(S); + addAutomaticObjDtors(ScopePos, scopeBeginPos, S); +} + +/// insertAutomaticObjDtors - Insert destructor CFGElements for variables with +/// automatic storage duration to CFGBlock's elements vector. Insertion will be +/// performed in place specified with iterator. +void CFGBuilder::insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, + LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { + BumpVectorContext& C = cfg->getBumpVectorContext(); + I = Blk->beginAutomaticObjDtorsInsert(I, B.distance(E), C); + while (B != E) + I = Blk->insertAutomaticObjDtor(I, *B++, S); +} + +/// appendAutomaticObjDtors - Append destructor CFGElements for variables with +/// automatic storage duration to CFGBlock's elements vector. Elements will be +/// appended to physical end of the vector which happens to be logical +/// beginning. +void CFGBuilder::appendAutomaticObjDtors(CFGBlock* Blk, + LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { + insertAutomaticObjDtors(Blk, Blk->begin(), B, E, S); +} + +/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for +/// variables with automatic storage duration to CFGBlock's elements vector. +/// Elements will be prepended to physical beginning of the vector which +/// happens to be logical end. Use blocks terminator as statement that specifies +/// destructors call site. +void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, + LocalScope::const_iterator B, LocalScope::const_iterator E) { + insertAutomaticObjDtors(Blk, Blk->end(), B, E, Blk->getTerminator()); +} + +/// Visit - Walk the subtree of a statement and add extra +/// blocks for ternary operators, &&, and ||. We also process "," and +/// DeclStmts (which may contain nested control-flow). +CFGBlock* CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { +tryAgain: + if (!S) { + badCFG = true; + return 0; + } + switch (S->getStmtClass()) { + default: + return VisitStmt(S, asc); + + case Stmt::AddrLabelExprClass: + return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); + + case Stmt::BinaryConditionalOperatorClass: + return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc); + + case Stmt::BinaryOperatorClass: + return VisitBinaryOperator(cast<BinaryOperator>(S), asc); + + case Stmt::BlockExprClass: + return VisitBlockExpr(cast<BlockExpr>(S), asc); + + case Stmt::BreakStmtClass: + return VisitBreakStmt(cast<BreakStmt>(S)); + + case Stmt::CallExprClass: + case Stmt::CXXOperatorCallExprClass: + return VisitCallExpr(cast<CallExpr>(S), asc); + + case Stmt::CaseStmtClass: + return VisitCaseStmt(cast<CaseStmt>(S)); + + case Stmt::ChooseExprClass: + return VisitChooseExpr(cast<ChooseExpr>(S), asc); + + case Stmt::CompoundStmtClass: + return VisitCompoundStmt(cast<CompoundStmt>(S)); + + case Stmt::ConditionalOperatorClass: + return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); + + case Stmt::ContinueStmtClass: + return VisitContinueStmt(cast<ContinueStmt>(S)); + + case Stmt::CXXCatchStmtClass: + return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); + + case Stmt::ExprWithCleanupsClass: + return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc); + + case Stmt::CXXBindTemporaryExprClass: + return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc); + + case Stmt::CXXConstructExprClass: + return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc); + + case Stmt::CXXFunctionalCastExprClass: + return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc); + + case Stmt::CXXTemporaryObjectExprClass: + return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc); + + case Stmt::CXXMemberCallExprClass: + return VisitCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), asc); + + case Stmt::CXXThrowExprClass: + return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); + + case Stmt::CXXTryStmtClass: + return VisitCXXTryStmt(cast<CXXTryStmt>(S)); + + case Stmt::DeclStmtClass: + return VisitDeclStmt(cast<DeclStmt>(S)); + + case Stmt::DefaultStmtClass: + return VisitDefaultStmt(cast<DefaultStmt>(S)); + + case Stmt::DoStmtClass: + return VisitDoStmt(cast<DoStmt>(S)); + + case Stmt::ForStmtClass: + return VisitForStmt(cast<ForStmt>(S)); + + case Stmt::GotoStmtClass: + return VisitGotoStmt(cast<GotoStmt>(S)); + + case Stmt::IfStmtClass: + return VisitIfStmt(cast<IfStmt>(S)); + + case Stmt::ImplicitCastExprClass: + return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc); + + case Stmt::IndirectGotoStmtClass: + return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); + + case Stmt::LabelStmtClass: + return VisitLabelStmt(cast<LabelStmt>(S)); + + case Stmt::MemberExprClass: + return VisitMemberExpr(cast<MemberExpr>(S), asc); + + case Stmt::ObjCAtCatchStmtClass: + return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); + + case Stmt::ObjCAtSynchronizedStmtClass: + return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); + + case Stmt::ObjCAtThrowStmtClass: + return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); + + case Stmt::ObjCAtTryStmtClass: + return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); + + case Stmt::ObjCForCollectionStmtClass: + return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); + + case Stmt::ParenExprClass: + S = cast<ParenExpr>(S)->getSubExpr(); + goto tryAgain; + + case Stmt::NullStmtClass: + return Block; + + case Stmt::ReturnStmtClass: + return VisitReturnStmt(cast<ReturnStmt>(S)); + + case Stmt::SizeOfAlignOfExprClass: + return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), asc); + + case Stmt::StmtExprClass: + return VisitStmtExpr(cast<StmtExpr>(S), asc); + + case Stmt::SwitchStmtClass: + return VisitSwitchStmt(cast<SwitchStmt>(S)); + + case Stmt::UnaryOperatorClass: + return VisitUnaryOperator(cast<UnaryOperator>(S), asc); + + case Stmt::WhileStmtClass: + return VisitWhileStmt(cast<WhileStmt>(S)); + } +} + +CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { + if (asc.alwaysAdd()) { + autoCreateBlock(); + appendStmt(Block, S, asc); + } + + return VisitChildren(S); +} + +/// VisitChildren - Visit the children of a Stmt. +CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { + CFGBlock *B = Block; + for (Stmt::child_range I = Terminator->children(); I; ++I) { + if (*I) B = Visit(*I); + } + return B; +} + +CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, + AddStmtChoice asc) { + AddressTakenLabels.insert(A->getLabel()); + + if (asc.alwaysAdd()) { + autoCreateBlock(); + appendStmt(Block, A, asc); + } + + return Block; +} + +CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U, + AddStmtChoice asc) { + if (asc.alwaysAdd()) { + autoCreateBlock(); + appendStmt(Block, U, asc); + } + + return Visit(U->getSubExpr(), AddStmtChoice()); +} + +CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, + AddStmtChoice asc) { + if (B->isLogicalOp()) { // && or || + CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); + appendStmt(ConfluenceBlock, B, asc); + + if (badCFG) + return 0; + + // create the block evaluating the LHS + CFGBlock* LHSBlock = createBlock(false); + LHSBlock->setTerminator(B); + + // create the block evaluating the RHS + Succ = ConfluenceBlock; + Block = NULL; + CFGBlock* RHSBlock = addStmt(B->getRHS()); + + if (RHSBlock) { + if (badCFG) + return 0; + } else { + // Create an empty block for cases where the RHS doesn't require + // any explicit statements in the CFG. + RHSBlock = createBlock(); + } + + // See if this is a known constant. + TryResult KnownVal = tryEvaluateBool(B->getLHS()); + if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) + KnownVal.negate(); + + // Now link the LHSBlock with RHSBlock. + if (B->getOpcode() == BO_LOr) { + addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); + addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); + } else { + assert(B->getOpcode() == BO_LAnd); + addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); + addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); + } + + // Generate the blocks for evaluating the LHS. + Block = LHSBlock; + return addStmt(B->getLHS()); + } + + if (B->getOpcode() == BO_Comma) { // , + autoCreateBlock(); + appendStmt(Block, B, asc); + addStmt(B->getRHS()); + return addStmt(B->getLHS()); + } + + if (B->isAssignmentOp()) { + if (asc.alwaysAdd()) { + autoCreateBlock(); + appendStmt(Block, B, asc); + } + Visit(B->getLHS()); + return Visit(B->getRHS()); + } + + if (asc.alwaysAdd()) { + autoCreateBlock(); + appendStmt(Block, B, asc); + } + + CFGBlock *RBlock = Visit(B->getRHS()); + CFGBlock *LBlock = Visit(B->getLHS()); + // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr + // containing a DoStmt, and the LHS doesn't create a new block, then we should + // return RBlock. Otherwise we'll incorrectly return NULL. + return (LBlock ? LBlock : RBlock); +} + +CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { + if (asc.alwaysAdd()) { + autoCreateBlock(); + appendStmt(Block, E, asc); + } + return Block; +} + +CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { + // "break" is a control-flow statement. Thus we stop processing the current + // block. + if (badCFG) + return 0; + + // Now create a new block that ends with the break statement. + Block = createBlock(false); + Block->setTerminator(B); + + // If there is no target for the break, then we are looking at an incomplete + // AST. This means that the CFG cannot be constructed. + if (BreakJumpTarget.block) { + addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B); + addSuccessor(Block, BreakJumpTarget.block); + } else + badCFG = true; + + + return Block; +} + +static bool CanThrow(Expr *E) { + QualType Ty = E->getType(); + if (Ty->isFunctionPointerType()) + Ty = Ty->getAs<PointerType>()->getPointeeType(); + else if (Ty->isBlockPointerType()) + Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); + + const FunctionType *FT = Ty->getAs<FunctionType>(); + if (FT) { + if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) + if (Proto->hasEmptyExceptionSpec()) + return false; + } + return true; +} + +CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { + // If this is a call to a no-return function, this stops the block here. + bool NoReturn = false; + if (getFunctionExtInfo(*C->getCallee()->getType()).getNoReturn()) { + NoReturn = true; + } + + bool AddEHEdge = false; + + // Languages without exceptions are assumed to not throw. + if (Context->getLangOptions().areExceptionsEnabled()) { + if (BuildOpts.AddEHEdges) + AddEHEdge = true; + } + + if (FunctionDecl *FD = C->getDirectCallee()) { + if (FD->hasAttr<NoReturnAttr>()) + NoReturn = true; + if (FD->hasAttr<NoThrowAttr>()) + AddEHEdge = false; + } + + if (!CanThrow(C->getCallee())) + AddEHEdge = false; + + if (!NoReturn && !AddEHEdge) + return VisitStmt(C, asc.withAlwaysAdd(true)); + + if (Block) { + Succ = Block; + if (badCFG) + return 0; + } + + Block = createBlock(!NoReturn); + appendStmt(Block, C, asc); + + if (NoReturn) { + // Wire this to the exit block directly. + addSuccessor(Block, &cfg->getExit()); + } + if (AddEHEdge) { + // Add exceptional edges. + if (TryTerminatedBlock) + addSuccessor(Block, TryTerminatedBlock); + else + addSuccessor(Block, &cfg->getExit()); + } + + return VisitChildren(C); +} + +CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, + AddStmtChoice asc) { + CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); + appendStmt(ConfluenceBlock, C, asc); + if (badCFG) + return 0; + + AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); + Succ = ConfluenceBlock; + Block = NULL; + CFGBlock* LHSBlock = Visit(C->getLHS(), alwaysAdd); + if (badCFG) + return 0; + + Succ = ConfluenceBlock; + Block = NULL; + CFGBlock* RHSBlock = Visit(C->getRHS(), alwaysAdd); + if (badCFG) + return 0; + + Block = createBlock(false); + // See if this is a known constant. + const TryResult& KnownVal = tryEvaluateBool(C->getCond()); + addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); + addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); + Block->setTerminator(C); + return addStmt(C->getCond()); +} + + +CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { + addLocalScopeAndDtors(C); + CFGBlock* LastBlock = Block; + + for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); + I != E; ++I ) { + // If we hit a segment of code just containing ';' (NullStmts), we can + // get a null block back. In such cases, just use the LastBlock + if (CFGBlock *newBlock = addStmt(*I)) + LastBlock = newBlock; + + if (badCFG) + return NULL; + } + + return LastBlock; +} + +CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C, + AddStmtChoice asc) { + const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C); + const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : NULL); + + // Create the confluence block that will "merge" the results of the ternary + // expression. + CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); + appendStmt(ConfluenceBlock, C, asc); + if (badCFG) + return 0; + + AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); + + // Create a block for the LHS expression if there is an LHS expression. A + // GCC extension allows LHS to be NULL, causing the condition to be the + // value that is returned instead. + // e.g: x ?: y is shorthand for: x ? x : y; + Succ = ConfluenceBlock; + Block = NULL; + CFGBlock* LHSBlock = 0; + const Expr *trueExpr = C->getTrueExpr(); + if (trueExpr != opaqueValue) { + LHSBlock = Visit(C->getTrueExpr(), alwaysAdd); + if (badCFG) + return 0; + Block = NULL; + } + + // Create the block for the RHS expression. + Succ = ConfluenceBlock; + CFGBlock* RHSBlock = Visit(C->getFalseExpr(), alwaysAdd); + if (badCFG) + return 0; + + // Create the block that will contain the condition. + Block = createBlock(false); + + // See if this is a known constant. + const TryResult& KnownVal = tryEvaluateBool(C->getCond()); + if (LHSBlock) + addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); + addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); + Block->setTerminator(C); + Expr *condExpr = C->getCond(); + + CFGBlock *result = 0; + + // Run the condition expression if it's not trivially expressed in + // terms of the opaque value (or if there is no opaque value). + if (condExpr != opaqueValue) result = addStmt(condExpr); + + // Before that, run the common subexpression if there was one. + // At least one of this or the above will be run. + if (opaqueValue) result = addStmt(BCO->getCommon()); + + return result; +} + +CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { + if (DS->isSingleDecl()) + return VisitDeclSubExpr(DS); + + CFGBlock *B = 0; + + // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. + typedef llvm::SmallVector<Decl*,10> BufTy; + BufTy Buf(DS->decl_begin(), DS->decl_end()); + + for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { + // Get the alignment of the new DeclStmt, padding out to >=8 bytes. + unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 + ? 8 : llvm::AlignOf<DeclStmt>::Alignment; + + // Allocate the DeclStmt using the BumpPtrAllocator. It will get + // automatically freed with the CFG. + DeclGroupRef DG(*I); + Decl *D = *I; + void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); + DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); + + // Append the fake DeclStmt to block. + B = VisitDeclSubExpr(DSNew); + } + + return B; +} + +/// VisitDeclSubExpr - Utility method to add block-level expressions for +/// DeclStmts and initializers in them. +CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt* DS) { + assert(DS->isSingleDecl() && "Can handle single declarations only."); + + VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl()); + + if (!VD) { + autoCreateBlock(); + appendStmt(Block, DS); + return Block; + } + + bool IsReference = false; + bool HasTemporaries = false; + + // Destructors of temporaries in initialization expression should be called + // after initialization finishes. + Expr *Init = VD->getInit(); + if (Init) { + IsReference = VD->getType()->isReferenceType(); + HasTemporaries = isa<ExprWithCleanups>(Init); + + if (BuildOpts.AddImplicitDtors && HasTemporaries) { + // Generate destructors for temporaries in initialization expression. + VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), + IsReference); + } + } + + autoCreateBlock(); + appendStmt(Block, DS); + + if (Init) { + if (HasTemporaries) + // For expression with temporaries go directly to subexpression to omit + // generating destructors for the second time. + Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); + else + Visit(Init); + } + + // If the type of VD is a VLA, then we must process its size expressions. + for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); + VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) + Block = addStmt(VA->getSizeExpr()); + + // Remove variable from local scope. + if (ScopePos && VD == *ScopePos) + ++ScopePos; + + return Block; +} + +CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { + // We may see an if statement in the middle of a basic block, or it may be the + // first statement we are processing. In either case, we create a new basic + // block. First, we create the blocks for the then...else statements, and + // then we create the block containing the if statement. If we were in the + // middle of a block, we stop processing that block. That block is then the + // implicit successor for the "then" and "else" clauses. + + // Save local scope position because in case of condition variable ScopePos + // won't be restored when traversing AST. + SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); + + // Create local scope for possible condition variable. + // Store scope position. Add implicit destructor. + if (VarDecl* VD = I->getConditionVariable()) { + LocalScope::const_iterator BeginScopePos = ScopePos; + addLocalScopeForVarDecl(VD); + addAutomaticObjDtors(ScopePos, BeginScopePos, I); + } + + // The block we were proccessing is now finished. Make it the successor + // block. + if (Block) { + Succ = Block; + if (badCFG) + return 0; + } + + // Process the false branch. + CFGBlock* ElseBlock = Succ; + + if (Stmt* Else = I->getElse()) { + SaveAndRestore<CFGBlock*> sv(Succ); + + // NULL out Block so that the recursive call to Visit will + // create a new basic block. + Block = NULL; + + // If branch is not a compound statement create implicit scope + // and add destructors. + if (!isa<CompoundStmt>(Else)) + addLocalScopeAndDtors(Else); + + ElseBlock = addStmt(Else); + + if (!ElseBlock) // Can occur when the Else body has all NullStmts. + ElseBlock = sv.get(); + else if (Block) { + if (badCFG) + return 0; + } + } + + // Process the true branch. + CFGBlock* ThenBlock; + { + Stmt* Then = I->getThen(); + assert(Then); + SaveAndRestore<CFGBlock*> sv(Succ); + Block = NULL; + + // If branch is not a compound statement create implicit scope + // and add destructors. + if (!isa<CompoundStmt>(Then)) + addLocalScopeAndDtors(Then); + + ThenBlock = addStmt(Then); + + if (!ThenBlock) { + // We can reach here if the "then" body has all NullStmts. + // Create an empty block so we can distinguish between true and false + // branches in path-sensitive analyses. + ThenBlock = createBlock(false); + addSuccessor(ThenBlock, sv.get()); + } else if (Block) { + if (badCFG) + return 0; + } + } + + // Now create a new block containing the if statement. + Block = createBlock(false); + + // Set the terminator of the new block to the If statement. + Block->setTerminator(I); + + // See if this is a known constant. + const TryResult &KnownVal = tryEvaluateBool(I->getCond()); + + // Now add the successors. + addSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); + addSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); + + // Add the condition as the last statement in the new block. This may create + // new blocks as the condition may contain control-flow. Any newly created + // blocks will be pointed to be "Block". + Block = addStmt(I->getCond()); + + // Finally, if the IfStmt contains a condition variable, add both the IfStmt + // and the condition variable initialization to the CFG. + if (VarDecl *VD = I->getConditionVariable()) { + if (Expr *Init = VD->getInit()) { + autoCreateBlock(); + appendStmt(Block, I, AddStmtChoice::AlwaysAdd); + addStmt(Init); + } + } + + return Block; +} + + +CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { + // If we were in the middle of a block we stop processing that block. + // + // NOTE: If a "return" appears in the middle of a block, this means that the + // code afterwards is DEAD (unreachable). We still keep a basic block + // for that code; a simple "mark-and-sweep" from the entry block will be + // able to report such dead blocks. + + // Create the new block. + Block = createBlock(false); + + // The Exit block is the only successor. + addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); + addSuccessor(Block, &cfg->getExit()); + + // Add the return statement to the block. This may create new blocks if R + // contains control-flow (short-circuit operations). + return VisitStmt(R, AddStmtChoice::AlwaysAdd); +} + +CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt *L) { + // Get the block of the labeled statement. Add it to our map. + addStmt(L->getSubStmt()); + CFGBlock *LabelBlock = Block; + + if (!LabelBlock) // This can happen when the body is empty, i.e. + LabelBlock = createBlock(); // scopes that only contains NullStmts. + + assert(LabelMap.find(L->getDecl()) == LabelMap.end() && + "label already in map"); + LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos); + + // Labels partition blocks, so this is the end of the basic block we were + // processing (L is the block's label). Because this is label (and we have + // already processed the substatement) there is no extra control-flow to worry + // about. + LabelBlock->setLabel(L); + if (badCFG) + return 0; + + // We set Block to NULL to allow lazy creation of a new block (if necessary); + Block = NULL; + + // This block is now the implicit successor of other blocks. + Succ = LabelBlock; + + return LabelBlock; +} + +CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { + // Goto is a control-flow statement. Thus we stop processing the current + // block and create a new one. + + Block = createBlock(false); + Block->setTerminator(G); + + // If we already know the mapping to the label block add the successor now. + LabelMapTy::iterator I = LabelMap.find(G->getLabel()); + + if (I == LabelMap.end()) + // We will need to backpatch this block later. + BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); + else { + JumpTarget JT = I->second; + addAutomaticObjDtors(ScopePos, JT.scopePosition, G); + addSuccessor(Block, JT.block); + } + + return Block; +} + +CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { + CFGBlock* LoopSuccessor = NULL; + + // Save local scope position because in case of condition variable ScopePos + // won't be restored when traversing AST. + SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); + + // Create local scope for init statement and possible condition variable. + // Add destructor for init statement and condition variable. + // Store scope position for continue statement. + if (Stmt* Init = F->getInit()) + addLocalScopeForStmt(Init); + LocalScope::const_iterator LoopBeginScopePos = ScopePos; + + if (VarDecl* VD = F->getConditionVariable()) + addLocalScopeForVarDecl(VD); + LocalScope::const_iterator ContinueScopePos = ScopePos; + + addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); + + // "for" is a control-flow statement. Thus we stop processing the current + // block. + if (Block) { + if (badCFG) + return 0; + LoopSuccessor = Block; + } else + LoopSuccessor = Succ; + + // Save the current value for the break targets. + // All breaks should go to the code following the loop. + SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); + BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); + + // Because of short-circuit evaluation, the condition of the loop can span + // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that + // evaluate the condition. + CFGBlock* ExitConditionBlock = createBlock(false); + CFGBlock* EntryConditionBlock = ExitConditionBlock; + + // Set the terminator for the "exit" condition block. + ExitConditionBlock->setTerminator(F); + + // Now add the actual condition to the condition block. Because the condition + // itself may contain control-flow, new blocks may be created. + if (Stmt* C = F->getCond()) { + Block = ExitConditionBlock; + EntryConditionBlock = addStmt(C); + if (badCFG) + return 0; + assert(Block == EntryConditionBlock || + (Block == 0 && EntryConditionBlock == Succ)); + + // If this block contains a condition variable, add both the condition + // variable and initializer to the CFG. + if (VarDecl *VD = F->getConditionVariable()) { + if (Expr *Init = VD->getInit()) { + autoCreateBlock(); + appendStmt(Block, F, AddStmtChoice::AlwaysAdd); + EntryConditionBlock = addStmt(Init); + assert(Block == EntryConditionBlock); + } + } + + if (Block) { + if (badCFG) + return 0; + } + } + + // The condition block is the implicit successor for the loop body as well as + // any code above the loop. + Succ = EntryConditionBlock; + + // See if this is a known constant. + TryResult KnownVal(true); + + if (F->getCond()) + KnownVal = tryEvaluateBool(F->getCond()); + + // Now create the loop body. + { + assert(F->getBody()); + + // Save the current values for Block, Succ, and continue targets. + SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); + SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); + + // Create a new block to contain the (bottom) of the loop body. + Block = NULL; + + // Loop body should end with destructor of Condition variable (if any). + addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); + + if (Stmt* I = F->getInc()) { + // Generate increment code in its own basic block. This is the target of + // continue statements. + Succ = addStmt(I); + } else { + // No increment code. Create a special, empty, block that is used as the + // target block for "looping back" to the start of the loop. + assert(Succ == EntryConditionBlock); + Succ = Block ? Block : createBlock(); + } + + // Finish up the increment (or empty) block if it hasn't been already. + if (Block) { + assert(Block == Succ); + if (badCFG) + return 0; + Block = 0; + } + + ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); + + // The starting block for the loop increment is the block that should + // represent the 'loop target' for looping back to the start of the loop. + ContinueJumpTarget.block->setLoopTarget(F); + + // If body is not a compound statement create implicit scope + // and add destructors. + if (!isa<CompoundStmt>(F->getBody())) + addLocalScopeAndDtors(F->getBody()); + + // Now populate the body block, and in the process create new blocks as we + // walk the body of the loop. + CFGBlock* BodyBlock = addStmt(F->getBody()); + + if (!BodyBlock) + BodyBlock = ContinueJumpTarget.block;//can happen for "for (...;...;...);" + else if (badCFG) + return 0; + + // This new body block is a successor to our "exit" condition block. + addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); + } + + // Link up the condition block with the code that follows the loop. (the + // false branch). + addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); + + // If the loop contains initialization, create a new block for those + // statements. This block can also contain statements that precede the loop. + if (Stmt* I = F->getInit()) { + Block = createBlock(); + return addStmt(I); + } + + // There is no loop initialization. We are thus basically a while loop. + // NULL out Block to force lazy block construction. + Block = NULL; + Succ = EntryConditionBlock; + return EntryConditionBlock; +} + +CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { + if (asc.alwaysAdd()) { + autoCreateBlock(); + appendStmt(Block, M, asc); + } + return Visit(M->getBase()); +} + +CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { + // Objective-C fast enumeration 'for' statements: + // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC + // + // for ( Type newVariable in collection_expression ) { statements } + // + // becomes: + // + // prologue: + // 1. collection_expression + // T. jump to loop_entry + // loop_entry: + // 1. side-effects of element expression + // 1. ObjCForCollectionStmt [performs binding to newVariable] + // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] + // TB: + // statements + // T. jump to loop_entry + // FB: + // what comes after + // + // and + // + // Type existingItem; + // for ( existingItem in expression ) { statements } + // + // becomes: + // + // the same with newVariable replaced with existingItem; the binding works + // the same except that for one ObjCForCollectionStmt::getElement() returns + // a DeclStmt and the other returns a DeclRefExpr. + // + + CFGBlock* LoopSuccessor = 0; + + if (Block) { + if (badCFG) + return 0; + LoopSuccessor = Block; + Block = 0; + } else + LoopSuccessor = Succ; + + // Build the condition blocks. + CFGBlock* ExitConditionBlock = createBlock(false); + CFGBlock* EntryConditionBlock = ExitConditionBlock; + + // Set the terminator for the "exit" condition block. + ExitConditionBlock->setTerminator(S); + + // The last statement in the block should be the ObjCForCollectionStmt, which + // performs the actual binding to 'element' and determines if there are any + // more items in the collection. + appendStmt(ExitConditionBlock, S); + Block = ExitConditionBlock; + + // Walk the 'element' expression to see if there are any side-effects. We + // generate new blocks as necesary. We DON'T add the statement by default to + // the CFG unless it contains control-flow. + EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); + if (Block) { + if (badCFG) + return 0; + Block = 0; + } + + // The condition block is the implicit successor for the loop body as well as + // any code above the loop. + Succ = EntryConditionBlock; + + // Now create the true branch. + { + // Save the current values for Succ, continue and break targets. + SaveAndRestore<CFGBlock*> save_Succ(Succ); + SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), + save_break(BreakJumpTarget); + + BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); + ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); + + CFGBlock* BodyBlock = addStmt(S->getBody()); + + if (!BodyBlock) + BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" + else if (Block) { + if (badCFG) + return 0; + } + + // This new body block is a successor to our "exit" condition block. + addSuccessor(ExitConditionBlock, BodyBlock); + } + + // Link up the condition block with the code that follows the loop. + // (the false branch). + addSuccessor(ExitConditionBlock, LoopSuccessor); + + // Now create a prologue block to contain the collection expression. + Block = createBlock(); + return addStmt(S->getCollection()); +} + +CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { + // FIXME: Add locking 'primitives' to CFG for @synchronized. + + // Inline the body. + CFGBlock *SyncBlock = addStmt(S->getSynchBody()); + + // The sync body starts its own basic block. This makes it a little easier + // for diagnostic clients. + if (SyncBlock) { + if (badCFG) + return 0; + + Block = 0; + Succ = SyncBlock; + } + + // Add the @synchronized to the CFG. + autoCreateBlock(); + appendStmt(Block, S, AddStmtChoice::AlwaysAdd); + + // Inline the sync expression. + return addStmt(S->getSynchExpr()); +} + +CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { + // FIXME + return NYS(); +} + +CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { + CFGBlock* LoopSuccessor = NULL; + + // Save local scope position because in case of condition variable ScopePos + // won't be restored when traversing AST. + SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); + + // Create local scope for possible condition variable. + // Store scope position for continue statement. + LocalScope::const_iterator LoopBeginScopePos = ScopePos; + if (VarDecl* VD = W->getConditionVariable()) { + addLocalScopeForVarDecl(VD); + addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); + } + + // "while" is a control-flow statement. Thus we stop processing the current + // block. + if (Block) { + if (badCFG) + return 0; + LoopSuccessor = Block; + } else + LoopSuccessor = Succ; + + // Because of short-circuit evaluation, the condition of the loop can span + // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that + // evaluate the condition. + CFGBlock* ExitConditionBlock = createBlock(false); + CFGBlock* EntryConditionBlock = ExitConditionBlock; + + // Set the terminator for the "exit" condition block. + ExitConditionBlock->setTerminator(W); + + // Now add the actual condition to the condition block. Because the condition + // itself may contain control-flow, new blocks may be created. Thus we update + // "Succ" after adding the condition. + if (Stmt* C = W->getCond()) { + Block = ExitConditionBlock; + EntryConditionBlock = addStmt(C); + // The condition might finish the current 'Block'. + Block = EntryConditionBlock; + + // If this block contains a condition variable, add both the condition + // variable and initializer to the CFG. + if (VarDecl *VD = W->getConditionVariable()) { + if (Expr *Init = VD->getInit()) { + autoCreateBlock(); + appendStmt(Block, W, AddStmtChoice::AlwaysAdd); + EntryConditionBlock = addStmt(Init); + assert(Block == EntryConditionBlock); + } + } + + if (Block) { + if (badCFG) + return 0; + } + } + + // The condition block is the implicit successor for the loop body as well as + // any code above the loop. + Succ = EntryConditionBlock; + + // See if this is a known constant. + const TryResult& KnownVal = tryEvaluateBool(W->getCond()); + + // Process the loop body. + { + assert(W->getBody()); + + // Save the current values for Block, Succ, and continue and break targets + SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); + SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), + save_break(BreakJumpTarget); + + // Create an empty block to represent the transition block for looping back + // to the head of the loop. + Block = 0; + assert(Succ == EntryConditionBlock); + Succ = createBlock(); + Succ->setLoopTarget(W); + ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); + + // All breaks should go to the code following the loop. + BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); + + // NULL out Block to force lazy instantiation of blocks for the body. + Block = NULL; + + // Loop body should end with destructor of Condition variable (if any). + addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); + + // If body is not a compound statement create implicit scope + // and add destructors. + if (!isa<CompoundStmt>(W->getBody())) + addLocalScopeAndDtors(W->getBody()); + + // Create the body. The returned block is the entry to the loop body. + CFGBlock* BodyBlock = addStmt(W->getBody()); + + if (!BodyBlock) + BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;" + else if (Block) { + if (badCFG) + return 0; + } + + // Add the loop body entry as a successor to the condition. + addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); + } + + // Link up the condition block with the code that follows the loop. (the + // false branch). + addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); + + // There can be no more statements in the condition block since we loop back + // to this block. NULL out Block to force lazy creation of another block. + Block = NULL; + + // Return the condition block, which is the dominating block for the loop. + Succ = EntryConditionBlock; + return EntryConditionBlock; +} + + +CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { + // FIXME: For now we pretend that @catch and the code it contains does not + // exit. + return Block; +} + +CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { + // FIXME: This isn't complete. We basically treat @throw like a return + // statement. + + // If we were in the middle of a block we stop processing that block. + if (badCFG) + return 0; + + // Create the new block. + Block = createBlock(false); + + // The Exit block is the only successor. + addSuccessor(Block, &cfg->getExit()); + + // Add the statement to the block. This may create new blocks if S contains + // control-flow (short-circuit operations). + return VisitStmt(S, AddStmtChoice::AlwaysAdd); +} + +CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { + // If we were in the middle of a block we stop processing that block. + if (badCFG) + return 0; + + // Create the new block. + Block = createBlock(false); + + if (TryTerminatedBlock) + // The current try statement is the only successor. + addSuccessor(Block, TryTerminatedBlock); + else + // otherwise the Exit block is the only successor. + addSuccessor(Block, &cfg->getExit()); + + // Add the statement to the block. This may create new blocks if S contains + // control-flow (short-circuit operations). + return VisitStmt(T, AddStmtChoice::AlwaysAdd); +} + +CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { + CFGBlock* LoopSuccessor = NULL; + + // "do...while" is a control-flow statement. Thus we stop processing the + // current block. + if (Block) { + if (badCFG) + return 0; + LoopSuccessor = Block; + } else + LoopSuccessor = Succ; + + // Because of short-circuit evaluation, the condition of the loop can span + // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that + // evaluate the condition. + CFGBlock* ExitConditionBlock = createBlock(false); + CFGBlock* EntryConditionBlock = ExitConditionBlock; + + // Set the terminator for the "exit" condition block. + ExitConditionBlock->setTerminator(D); + + // Now add the actual condition to the condition block. Because the condition + // itself may contain control-flow, new blocks may be created. + if (Stmt* C = D->getCond()) { + Block = ExitConditionBlock; + EntryConditionBlock = addStmt(C); + if (Block) { + if (badCFG) + return 0; + } + } + + // The condition block is the implicit successor for the loop body. + Succ = EntryConditionBlock; + + // See if this is a known constant. + const TryResult &KnownVal = tryEvaluateBool(D->getCond()); + + // Process the loop body. + CFGBlock* BodyBlock = NULL; + { + assert(D->getBody()); + + // Save the current values for Block, Succ, and continue and break targets + SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); + SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), + save_break(BreakJumpTarget); + + // All continues within this loop should go to the condition block + ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); + + // All breaks should go to the code following the loop. + BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); + + // NULL out Block to force lazy instantiation of blocks for the body. + Block = NULL; + + // If body is not a compound statement create implicit scope + // and add destructors. + if (!isa<CompoundStmt>(D->getBody())) + addLocalScopeAndDtors(D->getBody()); + + // Create the body. The returned block is the entry to the loop body. + BodyBlock = addStmt(D->getBody()); + + if (!BodyBlock) + BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" + else if (Block) { + if (badCFG) + return 0; + } + + if (!KnownVal.isFalse()) { + // Add an intermediate block between the BodyBlock and the + // ExitConditionBlock to represent the "loop back" transition. Create an + // empty block to represent the transition block for looping back to the + // head of the loop. + // FIXME: Can we do this more efficiently without adding another block? + Block = NULL; + Succ = BodyBlock; + CFGBlock *LoopBackBlock = createBlock(); + LoopBackBlock->setLoopTarget(D); + + // Add the loop body entry as a successor to the condition. + addSuccessor(ExitConditionBlock, LoopBackBlock); + } + else + addSuccessor(ExitConditionBlock, NULL); + } + + // Link up the condition block with the code that follows the loop. + // (the false branch). + addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); + + // There can be no more statements in the body block(s) since we loop back to + // the body. NULL out Block to force lazy creation of another block. + Block = NULL; + + // Return the loop body, which is the dominating block for the loop. + Succ = BodyBlock; + return BodyBlock; +} + +CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { + // "continue" is a control-flow statement. Thus we stop processing the + // current block. + if (badCFG) + return 0; + + // Now create a new block that ends with the continue statement. + Block = createBlock(false); + Block->setTerminator(C); + + // If there is no target for the continue, then we are looking at an + // incomplete AST. This means the CFG cannot be constructed. + if (ContinueJumpTarget.block) { + addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C); + addSuccessor(Block, ContinueJumpTarget.block); + } else + badCFG = true; + + return Block; +} + +CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, + AddStmtChoice asc) { + + if (asc.alwaysAdd()) { + autoCreateBlock(); + appendStmt(Block, E); + } + + // VLA types have expressions that must be evaluated. + if (E->isArgumentType()) { + for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr()); + VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) + addStmt(VA->getSizeExpr()); + } + + return Block; +} + +/// VisitStmtExpr - Utility method to handle (nested) statement +/// expressions (a GCC extension). +CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { + if (asc.alwaysAdd()) { + autoCreateBlock(); + appendStmt(Block, SE); + } + return VisitCompoundStmt(SE->getSubStmt()); +} + +CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { + // "switch" is a control-flow statement. Thus we stop processing the current + // block. + CFGBlock* SwitchSuccessor = NULL; + + // Save local scope position because in case of condition variable ScopePos + // won't be restored when traversing AST. + SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); + + // Create local scope for possible condition variable. + // Store scope position. Add implicit destructor. + if (VarDecl* VD = Terminator->getConditionVariable()) { + LocalScope::const_iterator SwitchBeginScopePos = ScopePos; + addLocalScopeForVarDecl(VD); + addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); + } + + if (Block) { + if (badCFG) + return 0; + SwitchSuccessor = Block; + } else SwitchSuccessor = Succ; + + // Save the current "switch" context. + SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), + save_default(DefaultCaseBlock); + SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); + + // Set the "default" case to be the block after the switch statement. If the + // switch statement contains a "default:", this value will be overwritten with + // the block for that code. + DefaultCaseBlock = SwitchSuccessor; + + // Create a new block that will contain the switch statement. + SwitchTerminatedBlock = createBlock(false); + + // Now process the switch body. The code after the switch is the implicit + // successor. + Succ = SwitchSuccessor; + BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); + + // When visiting the body, the case statements should automatically get linked + // up to the switch. We also don't keep a pointer to the body, since all + // control-flow from the switch goes to case/default statements. + assert(Terminator->getBody() && "switch must contain a non-NULL body"); + Block = NULL; + + // If body is not a compound statement create implicit scope + // and add destructors. + if (!isa<CompoundStmt>(Terminator->getBody())) + addLocalScopeAndDtors(Terminator->getBody()); + + addStmt(Terminator->getBody()); + if (Block) { + if (badCFG) + return 0; + } + + // If we have no "default:" case, the default transition is to the code + // following the switch body. + addSuccessor(SwitchTerminatedBlock, DefaultCaseBlock); + + // Add the terminator and condition in the switch block. + SwitchTerminatedBlock->setTerminator(Terminator); + assert(Terminator->getCond() && "switch condition must be non-NULL"); + Block = SwitchTerminatedBlock; + Block = addStmt(Terminator->getCond()); + + // Finally, if the SwitchStmt contains a condition variable, add both the + // SwitchStmt and the condition variable initialization to the CFG. + if (VarDecl *VD = Terminator->getConditionVariable()) { + if (Expr *Init = VD->getInit()) { + autoCreateBlock(); + appendStmt(Block, Terminator, AddStmtChoice::AlwaysAdd); + addStmt(Init); + } + } + + return Block; +} + +CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { + // CaseStmts are essentially labels, so they are the first statement in a + // block. + CFGBlock *TopBlock = 0, *LastBlock = 0; + + if (Stmt *Sub = CS->getSubStmt()) { + // For deeply nested chains of CaseStmts, instead of doing a recursion + // (which can blow out the stack), manually unroll and create blocks + // along the way. + while (isa<CaseStmt>(Sub)) { + CFGBlock *currentBlock = createBlock(false); + currentBlock->setLabel(CS); + + if (TopBlock) + addSuccessor(LastBlock, currentBlock); + else + TopBlock = currentBlock; + + addSuccessor(SwitchTerminatedBlock, currentBlock); + LastBlock = currentBlock; + + CS = cast<CaseStmt>(Sub); + Sub = CS->getSubStmt(); + } + + addStmt(Sub); + } + + CFGBlock* CaseBlock = Block; + if (!CaseBlock) + CaseBlock = createBlock(); + + // Cases statements partition blocks, so this is the top of the basic block we + // were processing (the "case XXX:" is the label). + CaseBlock->setLabel(CS); + + if (badCFG) + return 0; + + // Add this block to the list of successors for the block with the switch + // statement. + assert(SwitchTerminatedBlock); + addSuccessor(SwitchTerminatedBlock, CaseBlock); + + // We set Block to NULL to allow lazy creation of a new block (if necessary) + Block = NULL; + + if (TopBlock) { + addSuccessor(LastBlock, CaseBlock); + Succ = TopBlock; + } else { + // This block is now the implicit successor of other blocks. + Succ = CaseBlock; + } + + return Succ; +} + +CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { + if (Terminator->getSubStmt()) + addStmt(Terminator->getSubStmt()); + + DefaultCaseBlock = Block; + + if (!DefaultCaseBlock) + DefaultCaseBlock = createBlock(); + + // Default statements partition blocks, so this is the top of the basic block + // we were processing (the "default:" is the label). + DefaultCaseBlock->setLabel(Terminator); + + if (badCFG) + return 0; + + // Unlike case statements, we don't add the default block to the successors + // for the switch statement immediately. This is done when we finish + // processing the switch statement. This allows for the default case + // (including a fall-through to the code after the switch statement) to always + // be the last successor of a switch-terminated block. + + // We set Block to NULL to allow lazy creation of a new block (if necessary) + Block = NULL; + + // This block is now the implicit successor of other blocks. + Succ = DefaultCaseBlock; + + return DefaultCaseBlock; +} + +CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { + // "try"/"catch" is a control-flow statement. Thus we stop processing the + // current block. + CFGBlock* TrySuccessor = NULL; + + if (Block) { + if (badCFG) + return 0; + TrySuccessor = Block; + } else TrySuccessor = Succ; + + CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; + + // Create a new block that will contain the try statement. + CFGBlock *NewTryTerminatedBlock = createBlock(false); + // Add the terminator in the try block. + NewTryTerminatedBlock->setTerminator(Terminator); + + bool HasCatchAll = false; + for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { + // The code after the try is the implicit successor. + Succ = TrySuccessor; + CXXCatchStmt *CS = Terminator->getHandler(h); + if (CS->getExceptionDecl() == 0) { + HasCatchAll = true; + } + Block = NULL; + CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); + if (CatchBlock == 0) + return 0; + // Add this block to the list of successors for the block with the try + // statement. + addSuccessor(NewTryTerminatedBlock, CatchBlock); + } + if (!HasCatchAll) { + if (PrevTryTerminatedBlock) + addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); + else + addSuccessor(NewTryTerminatedBlock, &cfg->getExit()); + } + + // The code after the try is the implicit successor. + Succ = TrySuccessor; + + // Save the current "try" context. + SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); + TryTerminatedBlock = NewTryTerminatedBlock; + + assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); + Block = NULL; + Block = addStmt(Terminator->getTryBlock()); + return Block; +} + +CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { + // CXXCatchStmt are treated like labels, so they are the first statement in a + // block. + + // Save local scope position because in case of exception variable ScopePos + // won't be restored when traversing AST. + SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); + + // Create local scope for possible exception variable. + // Store scope position. Add implicit destructor. + if (VarDecl* VD = CS->getExceptionDecl()) { + LocalScope::const_iterator BeginScopePos = ScopePos; + addLocalScopeForVarDecl(VD); + addAutomaticObjDtors(ScopePos, BeginScopePos, CS); + } + + if (CS->getHandlerBlock()) + addStmt(CS->getHandlerBlock()); + + CFGBlock* CatchBlock = Block; + if (!CatchBlock) + CatchBlock = createBlock(); + + CatchBlock->setLabel(CS); + + if (badCFG) + return 0; + + // We set Block to NULL to allow lazy creation of a new block (if necessary) + Block = NULL; + + return CatchBlock; +} + +CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E, + AddStmtChoice asc) { + if (BuildOpts.AddImplicitDtors) { + // If adding implicit destructors visit the full expression for adding + // destructors of temporaries. + VisitForTemporaryDtors(E->getSubExpr()); + + // Full expression has to be added as CFGStmt so it will be sequenced + // before destructors of it's temporaries. + asc = asc.withAlwaysAdd(true); + } + return Visit(E->getSubExpr(), asc); +} + +CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, + AddStmtChoice asc) { + if (asc.alwaysAdd()) { + autoCreateBlock(); + appendStmt(Block, E, asc); + + // We do not want to propagate the AlwaysAdd property. + asc = asc.withAlwaysAdd(false); + } + return Visit(E->getSubExpr(), asc); +} + +CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C, + AddStmtChoice asc) { + autoCreateBlock(); + if (!C->isElidable()) + appendStmt(Block, C, asc.withAlwaysAdd(true)); + + return VisitChildren(C); +} + +CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, + AddStmtChoice asc) { + if (asc.alwaysAdd()) { + autoCreateBlock(); + appendStmt(Block, E, asc); + // We do not want to propagate the AlwaysAdd property. + asc = asc.withAlwaysAdd(false); + } + return Visit(E->getSubExpr(), asc); +} + +CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, + AddStmtChoice asc) { + autoCreateBlock(); + appendStmt(Block, C, asc.withAlwaysAdd(true)); + return VisitChildren(C); +} + +CFGBlock *CFGBuilder::VisitCXXMemberCallExpr(CXXMemberCallExpr *C, + AddStmtChoice asc) { + autoCreateBlock(); + appendStmt(Block, C, asc.withAlwaysAdd(true)); + return VisitChildren(C); +} + +CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E, + AddStmtChoice asc) { + if (asc.alwaysAdd()) { + autoCreateBlock(); + appendStmt(Block, E, asc); + } + return Visit(E->getSubExpr(), AddStmtChoice()); +} + +CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { + // Lazily create the indirect-goto dispatch block if there isn't one already. + CFGBlock* IBlock = cfg->getIndirectGotoBlock(); + + if (!IBlock) { + IBlock = createBlock(false); + cfg->setIndirectGotoBlock(IBlock); + } + + // IndirectGoto is a control-flow statement. Thus we stop processing the + // current block and create a new one. + if (badCFG) + return 0; + + Block = createBlock(false); + Block->setTerminator(I); + addSuccessor(Block, IBlock); + return addStmt(I->getTarget()); +} + +CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) { +tryAgain: + if (!E) { + badCFG = true; + return NULL; + } + switch (E->getStmtClass()) { + default: + return VisitChildrenForTemporaryDtors(E); + + case Stmt::BinaryOperatorClass: + return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E)); + + case Stmt::CXXBindTemporaryExprClass: + return VisitCXXBindTemporaryExprForTemporaryDtors( + cast<CXXBindTemporaryExpr>(E), BindToTemporary); + + case Stmt::BinaryConditionalOperatorClass: + case Stmt::ConditionalOperatorClass: + return VisitConditionalOperatorForTemporaryDtors( + cast<AbstractConditionalOperator>(E), BindToTemporary); + + case Stmt::ImplicitCastExprClass: + // For implicit cast we want BindToTemporary to be passed further. + E = cast<CastExpr>(E)->getSubExpr(); + goto tryAgain; + + case Stmt::ParenExprClass: + E = cast<ParenExpr>(E)->getSubExpr(); + goto tryAgain; + } +} + +CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) { + // When visiting children for destructors we want to visit them in reverse + // order. Because there's no reverse iterator for children must to reverse + // them in helper vector. + typedef llvm::SmallVector<Stmt *, 4> ChildrenVect; + ChildrenVect ChildrenRev; + for (Stmt::child_range I = E->children(); I; ++I) { + if (*I) ChildrenRev.push_back(*I); + } + + CFGBlock *B = Block; + for (ChildrenVect::reverse_iterator I = ChildrenRev.rbegin(), + L = ChildrenRev.rend(); I != L; ++I) { + if (CFGBlock *R = VisitForTemporaryDtors(*I)) + B = R; + } + return B; +} + +CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) { + if (E->isLogicalOp()) { + // Destructors for temporaries in LHS expression should be called after + // those for RHS expression. Even if this will unnecessarily create a block, + // this block will be used at least by the full expression. + autoCreateBlock(); + CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS()); + if (badCFG) + return NULL; + + Succ = ConfluenceBlock; + Block = NULL; + CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); + + if (RHSBlock) { + if (badCFG) + return NULL; + + // If RHS expression did produce destructors we need to connect created + // blocks to CFG in same manner as for binary operator itself. + CFGBlock *LHSBlock = createBlock(false); + LHSBlock->setTerminator(CFGTerminator(E, true)); + + // For binary operator LHS block is before RHS in list of predecessors + // of ConfluenceBlock. + std::reverse(ConfluenceBlock->pred_begin(), + ConfluenceBlock->pred_end()); + + // See if this is a known constant. + TryResult KnownVal = tryEvaluateBool(E->getLHS()); + if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr)) + KnownVal.negate(); + + // Link LHSBlock with RHSBlock exactly the same way as for binary operator + // itself. + if (E->getOpcode() == BO_LOr) { + addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); + addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); + } else { + assert (E->getOpcode() == BO_LAnd); + addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); + addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); + } + + Block = LHSBlock; + return LHSBlock; + } + + Block = ConfluenceBlock; + return ConfluenceBlock; + } + + if (E->isAssignmentOp()) { + // For assignment operator (=) LHS expression is visited + // before RHS expression. For destructors visit them in reverse order. + CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); + CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); + return LHSBlock ? LHSBlock : RHSBlock; + } + + // For any other binary operator RHS expression is visited before + // LHS expression (order of children). For destructors visit them in reverse + // order. + CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); + CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); + return RHSBlock ? RHSBlock : LHSBlock; +} + +CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( + CXXBindTemporaryExpr *E, bool BindToTemporary) { + // First add destructors for temporaries in subexpression. + CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr()); + if (!BindToTemporary) { + // If lifetime of temporary is not prolonged (by assigning to constant + // reference) add destructor for it. + autoCreateBlock(); + appendTemporaryDtor(Block, E); + B = Block; + } + return B; +} + +CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors( + AbstractConditionalOperator *E, bool BindToTemporary) { + // First add destructors for condition expression. Even if this will + // unnecessarily create a block, this block will be used at least by the full + // expression. + autoCreateBlock(); + CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond()); + if (badCFG) + return NULL; + if (BinaryConditionalOperator *BCO + = dyn_cast<BinaryConditionalOperator>(E)) { + ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon()); + if (badCFG) + return NULL; + } + + // Try to add block with destructors for LHS expression. + CFGBlock *LHSBlock = NULL; + Succ = ConfluenceBlock; + Block = NULL; + LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary); + if (badCFG) + return NULL; + + // Try to add block with destructors for RHS expression; + Succ = ConfluenceBlock; + Block = NULL; + CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(), + BindToTemporary); + if (badCFG) + return NULL; + + if (!RHSBlock && !LHSBlock) { + // If neither LHS nor RHS expression had temporaries to destroy don't create + // more blocks. + Block = ConfluenceBlock; + return Block; + } + + Block = createBlock(false); + Block->setTerminator(CFGTerminator(E, true)); + + // See if this is a known constant. + const TryResult &KnownVal = tryEvaluateBool(E->getCond()); + + if (LHSBlock) { + addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); + } else if (KnownVal.isFalse()) { + addSuccessor(Block, NULL); + } else { + addSuccessor(Block, ConfluenceBlock); + std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end()); + } + + if (!RHSBlock) + RHSBlock = ConfluenceBlock; + addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); + + return Block; +} + +} // end anonymous namespace + +/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has +/// no successors or predecessors. If this is the first block created in the +/// CFG, it is automatically set to be the Entry and Exit of the CFG. +CFGBlock* CFG::createBlock() { + bool first_block = begin() == end(); + + // Create the block. + CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); + new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); + Blocks.push_back(Mem, BlkBVC); + + // If this is the first block, set it as the Entry and Exit. + if (first_block) + Entry = Exit = &back(); + + // Return the block. + return &back(); +} + +/// buildCFG - Constructs a CFG from an AST. Ownership of the returned +/// CFG is returned to the caller. +CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, + BuildOptions BO) { + CFGBuilder Builder; + return Builder.buildCFG(D, Statement, C, BO); +} + +//===----------------------------------------------------------------------===// +// CFG: Queries for BlkExprs. +//===----------------------------------------------------------------------===// + +namespace { + typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; +} + +static void FindSubExprAssignments(Stmt *S, + llvm::SmallPtrSet<Expr*,50>& Set) { + if (!S) + return; + + for (Stmt::child_range I = S->children(); I; ++I) { + Stmt *child = *I; + if (!child) + continue; + + if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) + if (B->isAssignmentOp()) Set.insert(B); + + FindSubExprAssignments(child, Set); + } +} + +static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { + BlkExprMapTy* M = new BlkExprMapTy(); + + // Look for assignments that are used as subexpressions. These are the only + // assignments that we want to *possibly* register as a block-level + // expression. Basically, if an assignment occurs both in a subexpression and + // at the block-level, it is a block-level expression. + llvm::SmallPtrSet<Expr*,50> SubExprAssignments; + + for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) + for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) + if (CFGStmt S = BI->getAs<CFGStmt>()) + FindSubExprAssignments(S, SubExprAssignments); + + for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { + + // Iterate over the statements again on identify the Expr* and Stmt* at the + // block-level that are block-level expressions. + + for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { + CFGStmt CS = BI->getAs<CFGStmt>(); + if (!CS.isValid()) + continue; + if (Expr* Exp = dyn_cast<Expr>(CS.getStmt())) { + + if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { + // Assignment expressions that are not nested within another + // expression are really "statements" whose value is never used by + // another expression. + if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) + continue; + } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { + // Special handling for statement expressions. The last statement in + // the statement expression is also a block-level expr. + const CompoundStmt* C = Terminator->getSubStmt(); + if (!C->body_empty()) { + unsigned x = M->size(); + (*M)[C->body_back()] = x; + } + } + + unsigned x = M->size(); + (*M)[Exp] = x; + } + } + + // Look at terminators. The condition is a block-level expression. + + Stmt* S = (*I)->getTerminatorCondition(); + + if (S && M->find(S) == M->end()) { + unsigned x = M->size(); + (*M)[S] = x; + } + } + + return M; +} + +CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { + assert(S != NULL); + if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } + + BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); + BlkExprMapTy::iterator I = M->find(S); + return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); +} + +unsigned CFG::getNumBlkExprs() { + if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) + return M->size(); + + // We assume callers interested in the number of BlkExprs will want + // the map constructed if it doesn't already exist. + BlkExprMap = (void*) PopulateBlkExprMap(*this); + return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); +} + +//===----------------------------------------------------------------------===// +// Filtered walking of the CFG. +//===----------------------------------------------------------------------===// + +bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, + const CFGBlock *From, const CFGBlock *To) { + + if (F.IgnoreDefaultsWithCoveredEnums) { + // If the 'To' has no label or is labeled but the label isn't a + // CaseStmt then filter this edge. + if (const SwitchStmt *S = + dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) { + if (S->isAllEnumCasesCovered()) { + const Stmt *L = To->getLabel(); + if (!L || !isa<CaseStmt>(L)) + return true; + } + } + } + + return false; +} + +//===----------------------------------------------------------------------===// +// Cleanup: CFG dstor. +//===----------------------------------------------------------------------===// + +CFG::~CFG() { + delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); +} + +//===----------------------------------------------------------------------===// +// CFG pretty printing +//===----------------------------------------------------------------------===// + +namespace { + +class StmtPrinterHelper : public PrinterHelper { + typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; + typedef llvm::DenseMap<Decl*,std::pair<unsigned,unsigned> > DeclMapTy; + StmtMapTy StmtMap; + DeclMapTy DeclMap; + signed currentBlock; + unsigned currentStmt; + const LangOptions &LangOpts; +public: + + StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) + : currentBlock(0), currentStmt(0), LangOpts(LO) { + for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { + unsigned j = 1; + for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; + BI != BEnd; ++BI, ++j ) { + if (CFGStmt SE = BI->getAs<CFGStmt>()) { + std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); + StmtMap[SE] = P; + + if (DeclStmt* DS = dyn_cast<DeclStmt>(SE.getStmt())) { + DeclMap[DS->getSingleDecl()] = P; + + } else if (IfStmt* IS = dyn_cast<IfStmt>(SE.getStmt())) { + if (VarDecl* VD = IS->getConditionVariable()) + DeclMap[VD] = P; + + } else if (ForStmt* FS = dyn_cast<ForStmt>(SE.getStmt())) { + if (VarDecl* VD = FS->getConditionVariable()) + DeclMap[VD] = P; + + } else if (WhileStmt* WS = dyn_cast<WhileStmt>(SE.getStmt())) { + if (VarDecl* VD = WS->getConditionVariable()) + DeclMap[VD] = P; + + } else if (SwitchStmt* SS = dyn_cast<SwitchStmt>(SE.getStmt())) { + if (VarDecl* VD = SS->getConditionVariable()) + DeclMap[VD] = P; + + } else if (CXXCatchStmt* CS = dyn_cast<CXXCatchStmt>(SE.getStmt())) { + if (VarDecl* VD = CS->getExceptionDecl()) + DeclMap[VD] = P; + } + } + } + } + } + + virtual ~StmtPrinterHelper() {} + + const LangOptions &getLangOpts() const { return LangOpts; } + void setBlockID(signed i) { currentBlock = i; } + void setStmtID(unsigned i) { currentStmt = i; } + + virtual bool handledStmt(Stmt* S, llvm::raw_ostream& OS) { + StmtMapTy::iterator I = StmtMap.find(S); + + if (I == StmtMap.end()) + return false; + + if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock + && I->second.second == currentStmt) { + return false; + } + + OS << "[B" << I->second.first << "." << I->second.second << "]"; + return true; + } + + bool handleDecl(Decl* D, llvm::raw_ostream& OS) { + DeclMapTy::iterator I = DeclMap.find(D); + + if (I == DeclMap.end()) + return false; + + if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock + && I->second.second == currentStmt) { + return false; + } + + OS << "[B" << I->second.first << "." << I->second.second << "]"; + return true; + } +}; +} // end anonymous namespace + + +namespace { +class CFGBlockTerminatorPrint + : public StmtVisitor<CFGBlockTerminatorPrint,void> { + + llvm::raw_ostream& OS; + StmtPrinterHelper* Helper; + PrintingPolicy Policy; +public: + CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, + const PrintingPolicy &Policy) + : OS(os), Helper(helper), Policy(Policy) {} + + void VisitIfStmt(IfStmt* I) { + OS << "if "; + I->getCond()->printPretty(OS,Helper,Policy); + } + + // Default case. + void VisitStmt(Stmt* Terminator) { + Terminator->printPretty(OS, Helper, Policy); + } + + void VisitForStmt(ForStmt* F) { + OS << "for (" ; + if (F->getInit()) + OS << "..."; + OS << "; "; + if (Stmt* C = F->getCond()) + C->printPretty(OS, Helper, Policy); + OS << "; "; + if (F->getInc()) + OS << "..."; + OS << ")"; + } + + void VisitWhileStmt(WhileStmt* W) { + OS << "while " ; + if (Stmt* C = W->getCond()) + C->printPretty(OS, Helper, Policy); + } + + void VisitDoStmt(DoStmt* D) { + OS << "do ... while "; + if (Stmt* C = D->getCond()) + C->printPretty(OS, Helper, Policy); + } + + void VisitSwitchStmt(SwitchStmt* Terminator) { + OS << "switch "; + Terminator->getCond()->printPretty(OS, Helper, Policy); + } + + void VisitCXXTryStmt(CXXTryStmt* CS) { + OS << "try ..."; + } + + void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) { + C->getCond()->printPretty(OS, Helper, Policy); + OS << " ? ... : ..."; + } + + void VisitChooseExpr(ChooseExpr* C) { + OS << "__builtin_choose_expr( "; + C->getCond()->printPretty(OS, Helper, Policy); + OS << " )"; + } + + void VisitIndirectGotoStmt(IndirectGotoStmt* I) { + OS << "goto *"; + I->getTarget()->printPretty(OS, Helper, Policy); + } + + void VisitBinaryOperator(BinaryOperator* B) { + if (!B->isLogicalOp()) { + VisitExpr(B); + return; + } + + B->getLHS()->printPretty(OS, Helper, Policy); + + switch (B->getOpcode()) { + case BO_LOr: + OS << " || ..."; + return; + case BO_LAnd: + OS << " && ..."; + return; + default: + assert(false && "Invalid logical operator."); + } + } + + void VisitExpr(Expr* E) { + E->printPretty(OS, Helper, Policy); + } +}; +} // end anonymous namespace + +static void print_elem(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, + const CFGElement &E) { + if (CFGStmt CS = E.getAs<CFGStmt>()) { + Stmt *S = CS; + + if (Helper) { + + // special printing for statement-expressions. + if (StmtExpr* SE = dyn_cast<StmtExpr>(S)) { + CompoundStmt* Sub = SE->getSubStmt(); + + if (Sub->children()) { + OS << "({ ... ; "; + Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); + OS << " })\n"; + return; + } + } + // special printing for comma expressions. + if (BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { + if (B->getOpcode() == BO_Comma) { + OS << "... , "; + Helper->handledStmt(B->getRHS(),OS); + OS << '\n'; + return; + } + } + } + S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); + + if (isa<CXXOperatorCallExpr>(S)) { + OS << " (OperatorCall)"; + } else if (isa<CXXBindTemporaryExpr>(S)) { + OS << " (BindTemporary)"; + } + + // Expressions need a newline. + if (isa<Expr>(S)) + OS << '\n'; + + } else if (CFGInitializer IE = E.getAs<CFGInitializer>()) { + CXXCtorInitializer* I = IE; + if (I->isBaseInitializer()) + OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); + else OS << I->getAnyMember()->getName(); + + OS << "("; + if (Expr* IE = I->getInit()) + IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); + OS << ")"; + + if (I->isBaseInitializer()) + OS << " (Base initializer)\n"; + else OS << " (Member initializer)\n"; + + } else if (CFGAutomaticObjDtor DE = E.getAs<CFGAutomaticObjDtor>()){ + VarDecl* VD = DE.getVarDecl(); + Helper->handleDecl(VD, OS); + + const Type* T = VD->getType().getTypePtr(); + if (const ReferenceType* RT = T->getAs<ReferenceType>()) + T = RT->getPointeeType().getTypePtr(); + else if (const Type *ET = T->getArrayElementTypeNoTypeQual()) + T = ET; + + OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; + OS << " (Implicit destructor)\n"; + + } else if (CFGBaseDtor BE = E.getAs<CFGBaseDtor>()) { + const CXXBaseSpecifier *BS = BE.getBaseSpecifier(); + OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; + OS << " (Base object destructor)\n"; + + } else if (CFGMemberDtor ME = E.getAs<CFGMemberDtor>()) { + FieldDecl *FD = ME.getFieldDecl(); + + const Type *T = FD->getType().getTypePtr(); + if (const Type *ET = T->getArrayElementTypeNoTypeQual()) + T = ET; + + OS << "this->" << FD->getName(); + OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; + OS << " (Member object destructor)\n"; + + } else if (CFGTemporaryDtor TE = E.getAs<CFGTemporaryDtor>()) { + CXXBindTemporaryExpr *BT = TE.getBindTemporaryExpr(); + OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()"; + OS << " (Temporary object destructor)\n"; + } +} + +static void print_block(llvm::raw_ostream& OS, const CFG* cfg, + const CFGBlock& B, + StmtPrinterHelper* Helper, bool print_edges) { + + if (Helper) Helper->setBlockID(B.getBlockID()); + + // Print the header. + OS << "\n [ B" << B.getBlockID(); + + if (&B == &cfg->getEntry()) + OS << " (ENTRY) ]\n"; + else if (&B == &cfg->getExit()) + OS << " (EXIT) ]\n"; + else if (&B == cfg->getIndirectGotoBlock()) + OS << " (INDIRECT GOTO DISPATCH) ]\n"; + else + OS << " ]\n"; + + // Print the label of this block. + if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { + + if (print_edges) + OS << " "; + + if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) + OS << L->getName(); + else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { + OS << "case "; + C->getLHS()->printPretty(OS, Helper, + PrintingPolicy(Helper->getLangOpts())); + if (C->getRHS()) { + OS << " ... "; + C->getRHS()->printPretty(OS, Helper, + PrintingPolicy(Helper->getLangOpts())); + } + } else if (isa<DefaultStmt>(Label)) + OS << "default"; + else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { + OS << "catch ("; + if (CS->getExceptionDecl()) + CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), + 0); + else + OS << "..."; + OS << ")"; + + } else + assert(false && "Invalid label statement in CFGBlock."); + + OS << ":\n"; + } + + // Iterate through the statements in the block and print them. + unsigned j = 1; + + for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; + I != E ; ++I, ++j ) { + + // Print the statement # in the basic block and the statement itself. + if (print_edges) + OS << " "; + + OS << llvm::format("%3d", j) << ": "; + + if (Helper) + Helper->setStmtID(j); + + print_elem(OS,Helper,*I); + } + + // Print the terminator of this block. + if (B.getTerminator()) { + if (print_edges) + OS << " "; + + OS << " T: "; + + if (Helper) Helper->setBlockID(-1); + + CFGBlockTerminatorPrint TPrinter(OS, Helper, + PrintingPolicy(Helper->getLangOpts())); + TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt())); + OS << '\n'; + } + + if (print_edges) { + // Print the predecessors of this block. + OS << " Predecessors (" << B.pred_size() << "):"; + unsigned i = 0; + + for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); + I != E; ++I, ++i) { + + if (i == 8 || (i-8) == 0) + OS << "\n "; + + OS << " B" << (*I)->getBlockID(); + } + + OS << '\n'; + + // Print the successors of this block. + OS << " Successors (" << B.succ_size() << "):"; + i = 0; + + for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); + I != E; ++I, ++i) { + + if (i == 8 || (i-8) % 10 == 0) + OS << "\n "; + + if (*I) + OS << " B" << (*I)->getBlockID(); + else + OS << " NULL"; + } + + OS << '\n'; + } +} + + +/// dump - A simple pretty printer of a CFG that outputs to stderr. +void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } + +/// print - A simple pretty printer of a CFG that outputs to an ostream. +void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { + StmtPrinterHelper Helper(this, LO); + + // Print the entry block. + print_block(OS, this, getEntry(), &Helper, true); + + // Iterate through the CFGBlocks and print them one by one. + for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { + // Skip the entry block, because we already printed it. + if (&(**I) == &getEntry() || &(**I) == &getExit()) + continue; + + print_block(OS, this, **I, &Helper, true); + } + + // Print the exit block. + print_block(OS, this, getExit(), &Helper, true); + OS.flush(); +} + +/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. +void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { + print(llvm::errs(), cfg, LO); +} + +/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. +/// Generally this will only be called from CFG::print. +void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, + const LangOptions &LO) const { + StmtPrinterHelper Helper(cfg, LO); + print_block(OS, cfg, *this, &Helper, true); +} + +/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. +void CFGBlock::printTerminator(llvm::raw_ostream &OS, + const LangOptions &LO) const { + CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); + TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt())); +} + +Stmt* CFGBlock::getTerminatorCondition() { + Stmt *Terminator = this->Terminator; + if (!Terminator) + return NULL; + + Expr* E = NULL; + + switch (Terminator->getStmtClass()) { + default: + break; + + case Stmt::ForStmtClass: + E = cast<ForStmt>(Terminator)->getCond(); + break; + + case Stmt::WhileStmtClass: + E = cast<WhileStmt>(Terminator)->getCond(); + break; + + case Stmt::DoStmtClass: + E = cast<DoStmt>(Terminator)->getCond(); + break; + + case Stmt::IfStmtClass: + E = cast<IfStmt>(Terminator)->getCond(); + break; + + case Stmt::ChooseExprClass: + E = cast<ChooseExpr>(Terminator)->getCond(); + break; + + case Stmt::IndirectGotoStmtClass: + E = cast<IndirectGotoStmt>(Terminator)->getTarget(); + break; + + case Stmt::SwitchStmtClass: + E = cast<SwitchStmt>(Terminator)->getCond(); + break; + + case Stmt::BinaryConditionalOperatorClass: + E = cast<BinaryConditionalOperator>(Terminator)->getCond(); + break; + + case Stmt::ConditionalOperatorClass: + E = cast<ConditionalOperator>(Terminator)->getCond(); + break; + + case Stmt::BinaryOperatorClass: // '&&' and '||' + E = cast<BinaryOperator>(Terminator)->getLHS(); + break; + + case Stmt::ObjCForCollectionStmtClass: + return Terminator; + } + + return E ? E->IgnoreParens() : NULL; +} + +bool CFGBlock::hasBinaryBranchTerminator() const { + const Stmt *Terminator = this->Terminator; + if (!Terminator) + return false; + + Expr* E = NULL; + + switch (Terminator->getStmtClass()) { + default: + return false; + + case Stmt::ForStmtClass: + case Stmt::WhileStmtClass: + case Stmt::DoStmtClass: + case Stmt::IfStmtClass: + case Stmt::ChooseExprClass: + case Stmt::BinaryConditionalOperatorClass: + case Stmt::ConditionalOperatorClass: + case Stmt::BinaryOperatorClass: + return true; + } + + return E ? E->IgnoreParens() : NULL; +} + + +//===----------------------------------------------------------------------===// +// CFG Graphviz Visualization +//===----------------------------------------------------------------------===// + + +#ifndef NDEBUG +static StmtPrinterHelper* GraphHelper; +#endif + +void CFG::viewCFG(const LangOptions &LO) const { +#ifndef NDEBUG + StmtPrinterHelper H(this, LO); + GraphHelper = &H; + llvm::ViewGraph(this,"CFG"); + GraphHelper = NULL; +#endif +} + +namespace llvm { +template<> +struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { + + DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} + + static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { + +#ifndef NDEBUG + std::string OutSStr; + llvm::raw_string_ostream Out(OutSStr); + print_block(Out,Graph, *Node, GraphHelper, false); + std::string& OutStr = Out.str(); + + if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); + + // Process string output to make it nicer... + for (unsigned i = 0; i != OutStr.length(); ++i) + if (OutStr[i] == '\n') { // Left justify + OutStr[i] = '\\'; + OutStr.insert(OutStr.begin()+i+1, 'l'); + } + + return OutStr; +#else + return ""; +#endif + } +}; +} // end namespace llvm |
