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Diffstat (limited to 'include/llvm/Analysis/CallGraph.h')
| -rw-r--r-- | include/llvm/Analysis/CallGraph.h | 326 |
1 files changed, 326 insertions, 0 deletions
diff --git a/include/llvm/Analysis/CallGraph.h b/include/llvm/Analysis/CallGraph.h new file mode 100644 index 0000000..de83969 --- /dev/null +++ b/include/llvm/Analysis/CallGraph.h @@ -0,0 +1,326 @@ +//===- CallGraph.h - Build a Module's call graph ----------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This interface is used to build and manipulate a call graph, which is a very +// useful tool for interprocedural optimization. +// +// Every function in a module is represented as a node in the call graph. The +// callgraph node keeps track of which functions the are called by the function +// corresponding to the node. +// +// A call graph may contain nodes where the function that they correspond to is +// null. These 'external' nodes are used to represent control flow that is not +// represented (or analyzable) in the module. In particular, this analysis +// builds one external node such that: +// 1. All functions in the module without internal linkage will have edges +// from this external node, indicating that they could be called by +// functions outside of the module. +// 2. All functions whose address is used for something more than a direct +// call, for example being stored into a memory location will also have an +// edge from this external node. Since they may be called by an unknown +// caller later, they must be tracked as such. +// +// There is a second external node added for calls that leave this module. +// Functions have a call edge to the external node iff: +// 1. The function is external, reflecting the fact that they could call +// anything without internal linkage or that has its address taken. +// 2. The function contains an indirect function call. +// +// As an extension in the future, there may be multiple nodes with a null +// function. These will be used when we can prove (through pointer analysis) +// that an indirect call site can call only a specific set of functions. +// +// Because of these properties, the CallGraph captures a conservative superset +// of all of the caller-callee relationships, which is useful for +// transformations. +// +// The CallGraph class also attempts to figure out what the root of the +// CallGraph is, which it currently does by looking for a function named 'main'. +// If no function named 'main' is found, the external node is used as the entry +// node, reflecting the fact that any function without internal linkage could +// be called into (which is common for libraries). +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_ANALYSIS_CALLGRAPH_H +#define LLVM_ANALYSIS_CALLGRAPH_H + +#include "llvm/ADT/GraphTraits.h" +#include "llvm/ADT/STLExtras.h" +#include "llvm/Pass.h" +#include "llvm/Support/CallSite.h" +#include "llvm/System/IncludeFile.h" +#include <map> + +namespace llvm { + +class Function; +class Module; +class CallGraphNode; + +//===----------------------------------------------------------------------===// +// CallGraph class definition +// +class CallGraph { +protected: + Module *Mod; // The module this call graph represents + + typedef std::map<const Function *, CallGraphNode *> FunctionMapTy; + FunctionMapTy FunctionMap; // Map from a function to its node + +public: + static char ID; // Class identification, replacement for typeinfo + //===--------------------------------------------------------------------- + // Accessors... + // + typedef FunctionMapTy::iterator iterator; + typedef FunctionMapTy::const_iterator const_iterator; + + /// getModule - Return the module the call graph corresponds to. + /// + Module &getModule() const { return *Mod; } + + inline iterator begin() { return FunctionMap.begin(); } + inline iterator end() { return FunctionMap.end(); } + inline const_iterator begin() const { return FunctionMap.begin(); } + inline const_iterator end() const { return FunctionMap.end(); } + + // Subscripting operators, return the call graph node for the provided + // function + inline const CallGraphNode *operator[](const Function *F) const { + const_iterator I = FunctionMap.find(F); + assert(I != FunctionMap.end() && "Function not in callgraph!"); + return I->second; + } + inline CallGraphNode *operator[](const Function *F) { + const_iterator I = FunctionMap.find(F); + assert(I != FunctionMap.end() && "Function not in callgraph!"); + return I->second; + } + + /// Returns the CallGraphNode which is used to represent undetermined calls + /// into the callgraph. Override this if you want behavioral inheritance. + virtual CallGraphNode* getExternalCallingNode() const { return 0; } + + /// Return the root/main method in the module, or some other root node, such + /// as the externalcallingnode. Overload these if you behavioral + /// inheritance. + virtual CallGraphNode* getRoot() { return 0; } + virtual const CallGraphNode* getRoot() const { return 0; } + + //===--------------------------------------------------------------------- + // Functions to keep a call graph up to date with a function that has been + // modified. + // + + /// removeFunctionFromModule - Unlink the function from this module, returning + /// it. Because this removes the function from the module, the call graph + /// node is destroyed. This is only valid if the function does not call any + /// other functions (ie, there are no edges in it's CGN). The easiest way to + /// do this is to dropAllReferences before calling this. + /// + Function *removeFunctionFromModule(CallGraphNode *CGN); + Function *removeFunctionFromModule(Function *F) { + return removeFunctionFromModule((*this)[F]); + } + + /// changeFunction - This method changes the function associated with this + /// CallGraphNode, for use by transformations that need to change the + /// prototype of a Function (thus they must create a new Function and move the + /// old code over). + void changeFunction(Function *OldF, Function *NewF); + + /// getOrInsertFunction - This method is identical to calling operator[], but + /// it will insert a new CallGraphNode for the specified function if one does + /// not already exist. + CallGraphNode *getOrInsertFunction(const Function *F); + + //===--------------------------------------------------------------------- + // Pass infrastructure interface glue code... + // +protected: + CallGraph() {} + +public: + virtual ~CallGraph() { destroy(); } + + /// initialize - Call this method before calling other methods, + /// re/initializes the state of the CallGraph. + /// + void initialize(Module &M); + + virtual void print(std::ostream &o, const Module *M) const; + void print(std::ostream *o, const Module *M) const { if (o) print(*o, M); } + void dump() const; + +protected: + // destroy - Release memory for the call graph + virtual void destroy(); +}; + +//===----------------------------------------------------------------------===// +// CallGraphNode class definition +// +class CallGraphNode { + Function *F; + typedef std::pair<CallSite,CallGraphNode*> CallRecord; + std::vector<CallRecord> CalledFunctions; + + CallGraphNode(const CallGraphNode &); // Do not implement +public: + typedef std::vector<CallRecord> CalledFunctionsVector; + + //===--------------------------------------------------------------------- + // Accessor methods... + // + + typedef std::vector<CallRecord>::iterator iterator; + typedef std::vector<CallRecord>::const_iterator const_iterator; + + // getFunction - Return the function that this call graph node represents... + Function *getFunction() const { return F; } + + inline iterator begin() { return CalledFunctions.begin(); } + inline iterator end() { return CalledFunctions.end(); } + inline const_iterator begin() const { return CalledFunctions.begin(); } + inline const_iterator end() const { return CalledFunctions.end(); } + inline bool empty() const { return CalledFunctions.empty(); } + inline unsigned size() const { return (unsigned)CalledFunctions.size(); } + + // Subscripting operator - Return the i'th called function... + // + CallGraphNode *operator[](unsigned i) const { + return CalledFunctions[i].second; + } + + /// dump - Print out this call graph node. + /// + void dump() const; + void print(std::ostream &OS) const; + void print(std::ostream *OS) const { if (OS) print(*OS); } + + //===--------------------------------------------------------------------- + // Methods to keep a call graph up to date with a function that has been + // modified + // + + /// removeAllCalledFunctions - As the name implies, this removes all edges + /// from this CallGraphNode to any functions it calls. + void removeAllCalledFunctions() { + CalledFunctions.clear(); + } + + /// addCalledFunction - Add a function to the list of functions called by this + /// one. + void addCalledFunction(CallSite CS, CallGraphNode *M) { + CalledFunctions.push_back(std::make_pair(CS, M)); + } + + /// removeCallEdgeFor - This method removes the edge in the node for the + /// specified call site. Note that this method takes linear time, so it + /// should be used sparingly. + void removeCallEdgeFor(CallSite CS); + + /// removeAnyCallEdgeTo - This method removes all call edges from this node + /// to the specified callee function. This takes more time to execute than + /// removeCallEdgeTo, so it should not be used unless necessary. + void removeAnyCallEdgeTo(CallGraphNode *Callee); + + /// removeOneAbstractEdgeTo - Remove one edge associated with a null callsite + /// from this node to the specified callee function. + void removeOneAbstractEdgeTo(CallGraphNode *Callee); + + /// replaceCallSite - Make the edge in the node for Old CallSite be for + /// New CallSite instead. Note that this method takes linear time, so it + /// should be used sparingly. + void replaceCallSite(CallSite Old, CallSite New); + + friend class CallGraph; + + // CallGraphNode ctor - Create a node for the specified function. + inline CallGraphNode(Function *f) : F(f) {} +}; + +//===----------------------------------------------------------------------===// +// GraphTraits specializations for call graphs so that they can be treated as +// graphs by the generic graph algorithms. +// + +// Provide graph traits for tranversing call graphs using standard graph +// traversals. +template <> struct GraphTraits<CallGraphNode*> { + typedef CallGraphNode NodeType; + + typedef std::pair<CallSite, CallGraphNode*> CGNPairTy; + typedef std::pointer_to_unary_function<CGNPairTy, CallGraphNode*> CGNDerefFun; + + static NodeType *getEntryNode(CallGraphNode *CGN) { return CGN; } + + typedef mapped_iterator<NodeType::iterator, CGNDerefFun> ChildIteratorType; + + static inline ChildIteratorType child_begin(NodeType *N) { + return map_iterator(N->begin(), CGNDerefFun(CGNDeref)); + } + static inline ChildIteratorType child_end (NodeType *N) { + return map_iterator(N->end(), CGNDerefFun(CGNDeref)); + } + + static CallGraphNode *CGNDeref(CGNPairTy P) { + return P.second; + } + +}; + +template <> struct GraphTraits<const CallGraphNode*> { + typedef const CallGraphNode NodeType; + typedef NodeType::const_iterator ChildIteratorType; + + static NodeType *getEntryNode(const CallGraphNode *CGN) { return CGN; } + static inline ChildIteratorType child_begin(NodeType *N) { return N->begin();} + static inline ChildIteratorType child_end (NodeType *N) { return N->end(); } +}; + +template<> struct GraphTraits<CallGraph*> : public GraphTraits<CallGraphNode*> { + static NodeType *getEntryNode(CallGraph *CGN) { + return CGN->getExternalCallingNode(); // Start at the external node! + } + typedef std::pair<const Function*, CallGraphNode*> PairTy; + typedef std::pointer_to_unary_function<PairTy, CallGraphNode&> DerefFun; + + // nodes_iterator/begin/end - Allow iteration over all nodes in the graph + typedef mapped_iterator<CallGraph::iterator, DerefFun> nodes_iterator; + static nodes_iterator nodes_begin(CallGraph *CG) { + return map_iterator(CG->begin(), DerefFun(CGdereference)); + } + static nodes_iterator nodes_end (CallGraph *CG) { + return map_iterator(CG->end(), DerefFun(CGdereference)); + } + + static CallGraphNode &CGdereference(PairTy P) { + return *P.second; + } +}; + +template<> struct GraphTraits<const CallGraph*> : + public GraphTraits<const CallGraphNode*> { + static NodeType *getEntryNode(const CallGraph *CGN) { + return CGN->getExternalCallingNode(); + } + // nodes_iterator/begin/end - Allow iteration over all nodes in the graph + typedef CallGraph::const_iterator nodes_iterator; + static nodes_iterator nodes_begin(const CallGraph *CG) { return CG->begin(); } + static nodes_iterator nodes_end (const CallGraph *CG) { return CG->end(); } +}; + +} // End llvm namespace + +// Make sure that any clients of this file link in CallGraph.cpp +FORCE_DEFINING_FILE_TO_BE_LINKED(CallGraph) + +#endif |
