| //===--- CFG.h - 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. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_CLANG_CFG_H |
| #define LLVM_CLANG_CFG_H |
| |
| #include "llvm/ADT/PointerIntPair.h" |
| #include "llvm/ADT/GraphTraits.h" |
| #include "llvm/Support/Allocator.h" |
| #include "llvm/Support/Casting.h" |
| #include "clang/Analysis/Support/BumpVector.h" |
| #include "clang/Basic/SourceLocation.h" |
| #include <cassert> |
| |
| namespace llvm { |
| class raw_ostream; |
| } |
| namespace clang { |
| class Decl; |
| class Stmt; |
| class Expr; |
| class CFG; |
| class PrinterHelper; |
| class LangOptions; |
| class ASTContext; |
| |
| namespace { |
| // An element of the CFG for implicit descructor calls implied by the language |
| // rules. |
| class Dtor { |
| // Statement that introduces the variable. |
| Stmt *S; |
| // A token which ends the scope, return, goto, throw, }. |
| SourceLocation Loc; |
| public: |
| Dtor(Stmt *s, SourceLocation l) : S(s), Loc(l) { |
| } |
| SourceLocation getLoc() { return Loc; } |
| Stmt *getStmt() { return S; } |
| }; |
| } |
| |
| /// CFGElement - Represents a top-level expression in a basic block. |
| class CFGElement { |
| llvm::PointerIntPair<Stmt *, 2> Data; |
| public: |
| enum Type { StartScope, EndScope }; |
| explicit CFGElement() {} |
| CFGElement(Stmt *S, bool lvalue) : Data(S, lvalue ? 1 : 0) {} |
| CFGElement(Stmt *S, Type t) : Data(S, t == StartScope ? 2 : 3) {} |
| // CFGElement(Dtor *S, Type t) : Data(reinterpret_cast<Stmt*>(S), 4) {} |
| Stmt *getStmt() const { return Data.getPointer(); } |
| bool asLValue() const { return Data.getInt() == 1; } |
| bool asStartScope() const { return Data.getInt() == 2; } |
| bool asEndScope() const { return Data.getInt() == 3; } |
| bool asDtor() const { return Data.getInt() == 4; } |
| operator Stmt*() const { return getStmt(); } |
| operator bool() const { return getStmt() != 0; } |
| operator Dtor*() const { return reinterpret_cast<Dtor*>(getStmt()); } |
| }; |
| |
| /// CFGBlock - Represents a single basic block in a source-level CFG. |
| /// It consists of: |
| /// |
| /// (1) A set of statements/expressions (which may contain subexpressions). |
| /// (2) A "terminator" statement (not in the set of statements). |
| /// (3) A list of successors and predecessors. |
| /// |
| /// Terminator: The terminator represents the type of control-flow that occurs |
| /// at the end of the basic block. The terminator is a Stmt* referring to an |
| /// AST node that has control-flow: if-statements, breaks, loops, etc. |
| /// If the control-flow is conditional, the condition expression will appear |
| /// within the set of statements in the block (usually the last statement). |
| /// |
| /// Predecessors: the order in the set of predecessors is arbitrary. |
| /// |
| /// Successors: the order in the set of successors is NOT arbitrary. We |
| /// currently have the following orderings based on the terminator: |
| /// |
| /// Terminator Successor Ordering |
| /// ----------------------------------------------------- |
| /// if Then Block; Else Block |
| /// ? operator LHS expression; RHS expression |
| /// &&, || expression that uses result of && or ||, RHS |
| /// |
| class CFGBlock { |
| class StatementList { |
| typedef BumpVector<CFGElement> ImplTy; |
| ImplTy Impl; |
| public: |
| StatementList(BumpVectorContext &C) : Impl(C, 4) {} |
| |
| typedef std::reverse_iterator<ImplTy::iterator> iterator; |
| typedef std::reverse_iterator<ImplTy::const_iterator> const_iterator; |
| typedef ImplTy::iterator reverse_iterator; |
| typedef ImplTy::const_iterator const_reverse_iterator; |
| |
| void push_back(CFGElement e, BumpVectorContext &C) { Impl.push_back(e, C); } |
| CFGElement front() const { return Impl.back(); } |
| CFGElement back() const { return Impl.front(); } |
| |
| iterator begin() { return Impl.rbegin(); } |
| iterator end() { return Impl.rend(); } |
| const_iterator begin() const { return Impl.rbegin(); } |
| const_iterator end() const { return Impl.rend(); } |
| reverse_iterator rbegin() { return Impl.begin(); } |
| reverse_iterator rend() { return Impl.end(); } |
| const_reverse_iterator rbegin() const { return Impl.begin(); } |
| const_reverse_iterator rend() const { return Impl.end(); } |
| |
| CFGElement operator[](size_t i) const { |
| assert(i < Impl.size()); |
| return Impl[Impl.size() - 1 - i]; |
| } |
| |
| size_t size() const { return Impl.size(); } |
| bool empty() const { return Impl.empty(); } |
| }; |
| |
| /// Stmts - The set of statements in the basic block. |
| StatementList Stmts; |
| |
| /// Label - An (optional) label that prefixes the executable |
| /// statements in the block. When this variable is non-NULL, it is |
| /// either an instance of LabelStmt, SwitchCase or CXXCatchStmt. |
| Stmt *Label; |
| |
| /// Terminator - The terminator for a basic block that |
| /// indicates the type of control-flow that occurs between a block |
| /// and its successors. |
| Stmt *Terminator; |
| |
| /// LoopTarget - Some blocks are used to represent the "loop edge" to |
| /// the start of a loop from within the loop body. This Stmt* will be |
| /// refer to the loop statement for such blocks (and be null otherwise). |
| const Stmt *LoopTarget; |
| |
| /// BlockID - A numerical ID assigned to a CFGBlock during construction |
| /// of the CFG. |
| unsigned BlockID; |
| |
| /// Predecessors/Successors - Keep track of the predecessor / successor |
| /// CFG blocks. |
| typedef BumpVector<CFGBlock*> AdjacentBlocks; |
| AdjacentBlocks Preds; |
| AdjacentBlocks Succs; |
| |
| public: |
| explicit CFGBlock(unsigned blockid, BumpVectorContext &C) |
| : Stmts(C), Label(NULL), Terminator(NULL), LoopTarget(NULL), |
| BlockID(blockid), Preds(C, 1), Succs(C, 1) {} |
| ~CFGBlock() {} |
| |
| // Statement iterators |
| typedef StatementList::iterator iterator; |
| typedef StatementList::const_iterator const_iterator; |
| typedef StatementList::reverse_iterator reverse_iterator; |
| typedef StatementList::const_reverse_iterator const_reverse_iterator; |
| |
| CFGElement front() const { return Stmts.front(); } |
| CFGElement back() const { return Stmts.back(); } |
| |
| iterator begin() { return Stmts.begin(); } |
| iterator end() { return Stmts.end(); } |
| const_iterator begin() const { return Stmts.begin(); } |
| const_iterator end() const { return Stmts.end(); } |
| |
| reverse_iterator rbegin() { return Stmts.rbegin(); } |
| reverse_iterator rend() { return Stmts.rend(); } |
| const_reverse_iterator rbegin() const { return Stmts.rbegin(); } |
| const_reverse_iterator rend() const { return Stmts.rend(); } |
| |
| unsigned size() const { return Stmts.size(); } |
| bool empty() const { return Stmts.empty(); } |
| |
| CFGElement operator[](size_t i) const { return Stmts[i]; } |
| |
| // CFG iterators |
| typedef AdjacentBlocks::iterator pred_iterator; |
| typedef AdjacentBlocks::const_iterator const_pred_iterator; |
| typedef AdjacentBlocks::reverse_iterator pred_reverse_iterator; |
| typedef AdjacentBlocks::const_reverse_iterator const_pred_reverse_iterator; |
| |
| typedef AdjacentBlocks::iterator succ_iterator; |
| typedef AdjacentBlocks::const_iterator const_succ_iterator; |
| typedef AdjacentBlocks::reverse_iterator succ_reverse_iterator; |
| typedef AdjacentBlocks::const_reverse_iterator const_succ_reverse_iterator; |
| |
| pred_iterator pred_begin() { return Preds.begin(); } |
| pred_iterator pred_end() { return Preds.end(); } |
| const_pred_iterator pred_begin() const { return Preds.begin(); } |
| const_pred_iterator pred_end() const { return Preds.end(); } |
| |
| pred_reverse_iterator pred_rbegin() { return Preds.rbegin(); } |
| pred_reverse_iterator pred_rend() { return Preds.rend(); } |
| const_pred_reverse_iterator pred_rbegin() const { return Preds.rbegin(); } |
| const_pred_reverse_iterator pred_rend() const { return Preds.rend(); } |
| |
| succ_iterator succ_begin() { return Succs.begin(); } |
| succ_iterator succ_end() { return Succs.end(); } |
| const_succ_iterator succ_begin() const { return Succs.begin(); } |
| const_succ_iterator succ_end() const { return Succs.end(); } |
| |
| succ_reverse_iterator succ_rbegin() { return Succs.rbegin(); } |
| succ_reverse_iterator succ_rend() { return Succs.rend(); } |
| const_succ_reverse_iterator succ_rbegin() const { return Succs.rbegin(); } |
| const_succ_reverse_iterator succ_rend() const { return Succs.rend(); } |
| |
| unsigned succ_size() const { return Succs.size(); } |
| bool succ_empty() const { return Succs.empty(); } |
| |
| unsigned pred_size() const { return Preds.size(); } |
| bool pred_empty() const { return Preds.empty(); } |
| |
| // Manipulation of block contents |
| |
| void setTerminator(Stmt* Statement) { Terminator = Statement; } |
| void setLabel(Stmt* Statement) { Label = Statement; } |
| void setLoopTarget(const Stmt *loopTarget) { LoopTarget = loopTarget; } |
| |
| Stmt* getTerminator() { return Terminator; } |
| const Stmt* getTerminator() const { return Terminator; } |
| |
| Stmt* getTerminatorCondition(); |
| |
| const Stmt* getTerminatorCondition() const { |
| return const_cast<CFGBlock*>(this)->getTerminatorCondition(); |
| } |
| |
| const Stmt *getLoopTarget() const { return LoopTarget; } |
| |
| bool hasBinaryBranchTerminator() const; |
| |
| Stmt* getLabel() { return Label; } |
| const Stmt* getLabel() const { return Label; } |
| |
| unsigned getBlockID() const { return BlockID; } |
| |
| void dump(const CFG *cfg, const LangOptions &LO) const; |
| void print(llvm::raw_ostream &OS, const CFG* cfg, const LangOptions &LO) const; |
| void printTerminator(llvm::raw_ostream &OS, const LangOptions &LO) const; |
| |
| void addSuccessor(CFGBlock* Block, BumpVectorContext &C) { |
| if (Block) |
| Block->Preds.push_back(this, C); |
| Succs.push_back(Block, C); |
| } |
| |
| void appendStmt(Stmt* Statement, BumpVectorContext &C, bool asLValue) { |
| Stmts.push_back(CFGElement(Statement, asLValue), C); |
| } |
| void StartScope(Stmt* S, BumpVectorContext &C) { |
| Stmts.push_back(CFGElement(S, CFGElement::StartScope), C); |
| } |
| void EndScope(Stmt* S, BumpVectorContext &C) { |
| Stmts.push_back(CFGElement(S, CFGElement::EndScope), C); |
| } |
| }; |
| |
| |
| /// CFG - Represents a source-level, intra-procedural CFG that represents the |
| /// control-flow of a Stmt. The Stmt can represent an entire function body, |
| /// or a single expression. A CFG will always contain one empty block that |
| /// represents the Exit point of the CFG. A CFG will also contain a designated |
| /// Entry block. The CFG solely represents control-flow; it consists of |
| /// CFGBlocks which are simply containers of Stmt*'s in the AST the CFG |
| /// was constructed from. |
| class CFG { |
| public: |
| //===--------------------------------------------------------------------===// |
| // CFG Construction & Manipulation. |
| //===--------------------------------------------------------------------===// |
| |
| /// buildCFG - Builds a CFG from an AST. The responsibility to free the |
| /// constructed CFG belongs to the caller. |
| static CFG* buildCFG(const Decl *D, Stmt* AST, ASTContext *C, |
| bool AddEHEdges = false, |
| bool AddScopes = false); |
| |
| /// createBlock - Create a new block in the CFG. The CFG owns the block; |
| /// the caller should not directly free it. |
| CFGBlock* createBlock(); |
| |
| /// setEntry - Set the entry block of the CFG. This is typically used |
| /// only during CFG construction. Most CFG clients expect that the |
| /// entry block has no predecessors and contains no statements. |
| void setEntry(CFGBlock *B) { Entry = B; } |
| |
| /// setIndirectGotoBlock - Set the block used for indirect goto jumps. |
| /// This is typically used only during CFG construction. |
| void setIndirectGotoBlock(CFGBlock* B) { IndirectGotoBlock = B; } |
| |
| //===--------------------------------------------------------------------===// |
| // Block Iterators |
| //===--------------------------------------------------------------------===// |
| |
| typedef BumpVector<CFGBlock*> CFGBlockListTy; |
| typedef CFGBlockListTy::iterator iterator; |
| typedef CFGBlockListTy::const_iterator const_iterator; |
| typedef std::reverse_iterator<iterator> reverse_iterator; |
| typedef std::reverse_iterator<const_iterator> const_reverse_iterator; |
| |
| CFGBlock& front() { return *Blocks.front(); } |
| CFGBlock& back() { return *Blocks.back(); } |
| |
| iterator begin() { return Blocks.begin(); } |
| iterator end() { return Blocks.end(); } |
| const_iterator begin() const { return Blocks.begin(); } |
| const_iterator end() const { return Blocks.end(); } |
| |
| reverse_iterator rbegin() { return Blocks.rbegin(); } |
| reverse_iterator rend() { return Blocks.rend(); } |
| const_reverse_iterator rbegin() const { return Blocks.rbegin(); } |
| const_reverse_iterator rend() const { return Blocks.rend(); } |
| |
| CFGBlock& getEntry() { return *Entry; } |
| const CFGBlock& getEntry() const { return *Entry; } |
| CFGBlock& getExit() { return *Exit; } |
| const CFGBlock& getExit() const { return *Exit; } |
| |
| CFGBlock* getIndirectGotoBlock() { return IndirectGotoBlock; } |
| const CFGBlock* getIndirectGotoBlock() const { return IndirectGotoBlock; } |
| |
| //===--------------------------------------------------------------------===// |
| // Member templates useful for various batch operations over CFGs. |
| //===--------------------------------------------------------------------===// |
| |
| template <typename CALLBACK> |
| void VisitBlockStmts(CALLBACK& O) const { |
| for (const_iterator I=begin(), E=end(); I != E; ++I) |
| for (CFGBlock::const_iterator BI=(*I)->begin(), BE=(*I)->end(); |
| BI != BE; ++BI) |
| O(*BI); |
| } |
| |
| //===--------------------------------------------------------------------===// |
| // CFG Introspection. |
| //===--------------------------------------------------------------------===// |
| |
| struct BlkExprNumTy { |
| const signed Idx; |
| explicit BlkExprNumTy(signed idx) : Idx(idx) {} |
| explicit BlkExprNumTy() : Idx(-1) {} |
| operator bool() const { return Idx >= 0; } |
| operator unsigned() const { assert(Idx >=0); return (unsigned) Idx; } |
| }; |
| |
| bool isBlkExpr(const Stmt* S) { return getBlkExprNum(S); } |
| BlkExprNumTy getBlkExprNum(const Stmt* S); |
| unsigned getNumBlkExprs(); |
| |
| /// getNumBlockIDs - Returns the total number of BlockIDs allocated (which |
| /// start at 0). |
| unsigned getNumBlockIDs() const { return NumBlockIDs; } |
| |
| //===--------------------------------------------------------------------===// |
| // CFG Debugging: Pretty-Printing and Visualization. |
| //===--------------------------------------------------------------------===// |
| |
| void viewCFG(const LangOptions &LO) const; |
| void print(llvm::raw_ostream& OS, const LangOptions &LO) const; |
| void dump(const LangOptions &LO) const; |
| |
| //===--------------------------------------------------------------------===// |
| // Internal: constructors and data. |
| //===--------------------------------------------------------------------===// |
| |
| CFG() : Entry(NULL), Exit(NULL), IndirectGotoBlock(NULL), NumBlockIDs(0), |
| BlkExprMap(NULL), Blocks(BlkBVC, 10) {} |
| |
| ~CFG(); |
| |
| llvm::BumpPtrAllocator& getAllocator() { |
| return BlkBVC.getAllocator(); |
| } |
| |
| BumpVectorContext &getBumpVectorContext() { |
| return BlkBVC; |
| } |
| |
| private: |
| CFGBlock* Entry; |
| CFGBlock* Exit; |
| CFGBlock* IndirectGotoBlock; // Special block to contain collective dispatch |
| // for indirect gotos |
| unsigned NumBlockIDs; |
| |
| // BlkExprMap - An opaque pointer to prevent inclusion of DenseMap.h. |
| // It represents a map from Expr* to integers to record the set of |
| // block-level expressions and their "statement number" in the CFG. |
| void* BlkExprMap; |
| |
| BumpVectorContext BlkBVC; |
| |
| CFGBlockListTy Blocks; |
| |
| }; |
| } // end namespace clang |
| |
| //===----------------------------------------------------------------------===// |
| // GraphTraits specializations for CFG basic block graphs (source-level CFGs) |
| //===----------------------------------------------------------------------===// |
| |
| namespace llvm { |
| |
| /// Implement simplify_type for CFGElement, so that we can dyn_cast from |
| /// CFGElement to a specific Stmt class. |
| template <> struct simplify_type<const ::clang::CFGElement> { |
| typedef ::clang::Stmt* SimpleType; |
| static SimpleType getSimplifiedValue(const ::clang::CFGElement &Val) { |
| return Val.getStmt(); |
| } |
| }; |
| |
| template <> struct simplify_type< ::clang::CFGElement> |
| : public simplify_type<const ::clang::CFGElement> {}; |
| |
| // Traits for: CFGBlock |
| |
| template <> struct GraphTraits< ::clang::CFGBlock* > { |
| typedef ::clang::CFGBlock NodeType; |
| typedef ::clang::CFGBlock::succ_iterator ChildIteratorType; |
| |
| static NodeType* getEntryNode(::clang::CFGBlock* BB) |
| { return BB; } |
| |
| static inline ChildIteratorType child_begin(NodeType* N) |
| { return N->succ_begin(); } |
| |
| static inline ChildIteratorType child_end(NodeType* N) |
| { return N->succ_end(); } |
| }; |
| |
| template <> struct GraphTraits< const ::clang::CFGBlock* > { |
| typedef const ::clang::CFGBlock NodeType; |
| typedef ::clang::CFGBlock::const_succ_iterator ChildIteratorType; |
| |
| static NodeType* getEntryNode(const clang::CFGBlock* BB) |
| { return BB; } |
| |
| static inline ChildIteratorType child_begin(NodeType* N) |
| { return N->succ_begin(); } |
| |
| static inline ChildIteratorType child_end(NodeType* N) |
| { return N->succ_end(); } |
| }; |
| |
| template <> struct GraphTraits<Inverse<const ::clang::CFGBlock*> > { |
| typedef const ::clang::CFGBlock NodeType; |
| typedef ::clang::CFGBlock::const_pred_iterator ChildIteratorType; |
| |
| static NodeType *getEntryNode(Inverse<const ::clang::CFGBlock*> G) |
| { return G.Graph; } |
| |
| static inline ChildIteratorType child_begin(NodeType* N) |
| { return N->pred_begin(); } |
| |
| static inline ChildIteratorType child_end(NodeType* N) |
| { return N->pred_end(); } |
| }; |
| |
| // Traits for: CFG |
| |
| template <> struct GraphTraits< ::clang::CFG* > |
| : public GraphTraits< ::clang::CFGBlock* > { |
| |
| typedef ::clang::CFG::iterator nodes_iterator; |
| |
| static NodeType *getEntryNode(::clang::CFG* F) { return &F->getEntry(); } |
| static nodes_iterator nodes_begin(::clang::CFG* F) { return F->begin(); } |
| static nodes_iterator nodes_end(::clang::CFG* F) { return F->end(); } |
| }; |
| |
| template <> struct GraphTraits<const ::clang::CFG* > |
| : public GraphTraits<const ::clang::CFGBlock* > { |
| |
| typedef ::clang::CFG::const_iterator nodes_iterator; |
| |
| static NodeType *getEntryNode( const ::clang::CFG* F) { |
| return &F->getEntry(); |
| } |
| static nodes_iterator nodes_begin( const ::clang::CFG* F) { |
| return F->begin(); |
| } |
| static nodes_iterator nodes_end( const ::clang::CFG* F) { |
| return F->end(); |
| } |
| }; |
| |
| template <> struct GraphTraits<Inverse<const ::clang::CFG*> > |
| : public GraphTraits<Inverse<const ::clang::CFGBlock*> > { |
| |
| typedef ::clang::CFG::const_iterator nodes_iterator; |
| |
| static NodeType *getEntryNode(const ::clang::CFG* F) { return &F->getExit(); } |
| static nodes_iterator nodes_begin(const ::clang::CFG* F) { return F->begin();} |
| static nodes_iterator nodes_end(const ::clang::CFG* F) { return F->end(); } |
| }; |
| } // end llvm namespace |
| #endif |
