X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FAnalysis%2FCallGraph.h;h=44cd3d0f706b12754dece2d4e7378ab67a9fcf8c;hb=3fd813ef423e23d7f57ed3784d423ca503cd3578;hp=d44fa5fc3a7876371c67d97a594ee8b615a60ee4;hpb=a7980c0a089d03dd64606bdc1fdb10cb914a5f4e;p=oota-llvm.git diff --git a/include/llvm/Analysis/CallGraph.h b/include/llvm/Analysis/CallGraph.h index d44fa5fc3a7..44cd3d0f706 100644 --- a/include/llvm/Analysis/CallGraph.h +++ b/include/llvm/Analysis/CallGraph.h @@ -1,263 +1,468 @@ -//===- CallGraph.h - Build a Module's call graph -----------------*- C++ -*--=// +//===- CallGraph.h - Build a Module's call graph ----------------*- C++ -*-===// // -// This interface is used to build and manipulate a call graph, which is a very -// useful tool for interprocedural optimization. +// The LLVM Compiler Infrastructure // -// Every method in a module is represented as a node in the call graph. The -// callgraph node keeps track of which methods the are called by the method -// corresponding to the node. -// -// A call graph will contain nodes where the method that they correspond to is -// null. This 'external' node is used to represent control flow that is not -// represented (or analyzable) in the module. As such, the external node will -// have edges to methods with the following properties: -// 1. All methods in the module without internal linkage, since they could -// be called by methods outside of the our analysis capability. -// 2. All methods whose address is used for something more than a direct call, -// for example being stored into a memory location. Since they may be -// called by an unknown caller later, they must be tracked as such. -// -// Similarly, methods have a call edge to the external node iff: -// 1. The method is external, reflecting the fact that they could call -// anything without internal linkage or that has its address taken. -// 2. The method contains an indirect method call. -// -// As an extension in the future, there may be multiple nodes with a null -// method. These will be used when we can prove (through pointer analysis) that -// an indirect call site can call only a specific set of methods. -// -// 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 is currently does by looking for a method named 'main'. -// If no method named 'main' is found, the external node is used as the entry -// node, reflecting the fact that any method without internal linkage could -// be called into (which is common for libraries). +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// +/// \file +/// +/// This file provides interfaces 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 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 "Support/GraphTraits.h" +#include "llvm/ADT/GraphTraits.h" +#include "llvm/ADT/OwningPtr.h" +#include "llvm/ADT/STLExtras.h" +#include "llvm/IR/Function.h" #include "llvm/Pass.h" +#include "llvm/Support/CallSite.h" +#include "llvm/Support/IncludeFile.h" +#include "llvm/Support/ValueHandle.h" +#include + +namespace llvm { + class Function; class Module; class CallGraphNode; -//===----------------------------------------------------------------------===// -// CallGraph class definition -// -class CallGraph : public Pass { - Module *Mod; // The module this call graph represents +/// \brief The basic data container for the call graph of a \c Module of IR. +/// +/// This class exposes both the interface to the call graph for a module of IR. +/// +/// The core call graph itself can also be updated to reflect changes to the IR. +class CallGraph { + Module &M; - typedef std::map MethodMapTy; - MethodMapTy MethodMap; // Map from a method to its node + typedef std::map FunctionMapTy; + + /// \brief A map from \c Function* to \c CallGraphNode*. + FunctionMapTy FunctionMap; + + /// \brief Root is root of the call graph, or the external node if a 'main' + /// function couldn't be found. + CallGraphNode *Root; + + /// \brief This node has edges to all external functions and those internal + /// functions that have their address taken. + CallGraphNode *ExternalCallingNode; + + /// \brief This node has edges to it from all functions making indirect calls + /// or calling an external function. + CallGraphNode *CallsExternalNode; + + /// \brief Replace the function represented by this node by another. + /// + /// This does not rescan the body of the function, so it is suitable when + /// splicing the body of one function to another while also updating all + /// callers from the old function to the new. + void spliceFunction(const Function *From, const Function *To); + + /// \brief Add a function to the call graph, and link the node to all of the + /// functions that it calls. + void addToCallGraph(Function *F); - // Root is root of the call graph, or the external node if a 'main' function - // couldn't be found. ExternalNode is equivalent to (*this)[0]. - // - CallGraphNode *Root, *ExternalNode; public: + CallGraph(Module &M); + ~CallGraph(); - //===--------------------------------------------------------------------- - // Accessors... - // - typedef MethodMapTy::iterator iterator; - typedef MethodMapTy::const_iterator const_iterator; + void print(raw_ostream &OS) const; + void dump() const; + + typedef FunctionMapTy::iterator iterator; + typedef FunctionMapTy::const_iterator const_iterator; - inline CallGraphNode *getRoot() { return Root; } - inline const CallGraphNode *getRoot() const { return Root; } - inline iterator begin() { return MethodMap.begin(); } - inline iterator end() { return MethodMap.end(); } - inline const_iterator begin() const { return MethodMap.begin(); } - inline const_iterator end() const { return MethodMap.end(); } + /// \brief Returns the module the call graph corresponds to. + Module &getModule() const { return M; } + 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 method + /// \brief Returns the call graph node for the provided function. inline const CallGraphNode *operator[](const Function *F) const { - const_iterator I = MethodMap.find(F); - assert(I != MethodMap.end() && "Method not in callgraph!"); + const_iterator I = FunctionMap.find(F); + assert(I != FunctionMap.end() && "Function not in callgraph!"); return I->second; } + + /// \brief Returns the call graph node for the provided function. inline CallGraphNode *operator[](const Function *F) { - const_iterator I = MethodMap.find(F); - assert(I != MethodMap.end() && "Method not in callgraph!"); + const_iterator I = FunctionMap.find(F); + assert(I != FunctionMap.end() && "Function not in callgraph!"); return I->second; } + /// \brief Returns the \c CallGraphNode which is used to represent + /// undetermined calls into the callgraph. + CallGraphNode *getExternalCallingNode() const { return ExternalCallingNode; } + + CallGraphNode *getCallsExternalNode() const { return CallsExternalNode; } + //===--------------------------------------------------------------------- - // Methods to keep a call graph up to date with a method that has been - // modified + // Functions to keep a call graph up to date with a function that has been + // modified. // - void addMethodToModule(Function *Meth); + /// \brief 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); + + /// \brief Similar to operator[], but this will insert a new CallGraphNode for + /// \c F if one does not already exist. + CallGraphNode *getOrInsertFunction(const Function *F); +}; - // removeMethodFromModule - Unlink the method from this module, returning it. - // Because this removes the method from the module, the call graph node is - // destroyed. This is only valid if the method does not call any other - // methods (ie, there are no edges in it's CGN). The easiest way to do this - // is to dropAllReferences before calling this. - // - Function *removeMethodFromModule(CallGraphNode *CGN); - Function *removeMethodFromModule(Function *Meth) { - return removeMethodFromModule((*this)[Meth]); +/// \brief A node in the call graph for a module. +/// +/// Typically represents a function in the call graph. There are also special +/// "null" nodes used to represent theoretical entries in the call graph. +class CallGraphNode { +public: + /// \brief A pair of the calling instruction (a call or invoke) + /// and the call graph node being called. + typedef std::pair CallRecord; + +public: + typedef std::vector CalledFunctionsVector; + + /// \brief Creates a node for the specified function. + inline CallGraphNode(Function *F) : F(F), NumReferences(0) {} + + ~CallGraphNode() { + assert(NumReferences == 0 && "Node deleted while references remain"); } + typedef std::vector::iterator iterator; + typedef std::vector::const_iterator const_iterator; + + /// \brief Returns 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(); } + + /// \brief Returns the number of other CallGraphNodes in this CallGraph that + /// reference this node in their callee list. + unsigned getNumReferences() const { return NumReferences; } + + /// \brief Returns the i'th called function. + CallGraphNode *operator[](unsigned i) const { + assert(i < CalledFunctions.size() && "Invalid index"); + return CalledFunctions[i].second; + } + + /// \brief Print out this call graph node. + void dump() const; + void print(raw_ostream &OS) const; //===--------------------------------------------------------------------- - // Pass infrastructure interface glue code... + // Methods to keep a call graph up to date with a function that has been + // modified // - static AnalysisID ID; // We are an analysis, we must have an ID - - CallGraph(AnalysisID AID) : Root(0) { assert(AID == ID); } - ~CallGraph() { destroy(); } - virtual const char *getPassName() const { return "Call Graph Construction"; } + /// \brief Removes all edges from this CallGraphNode to any functions it + /// calls. + void removeAllCalledFunctions() { + while (!CalledFunctions.empty()) { + CalledFunctions.back().second->DropRef(); + CalledFunctions.pop_back(); + } + } - // run - Compute the call graph for the specified module. - virtual bool run(Module *TheModule); + /// \brief Moves all the callee information from N to this node. + void stealCalledFunctionsFrom(CallGraphNode *N) { + assert(CalledFunctions.empty() && + "Cannot steal callsite information if I already have some"); + std::swap(CalledFunctions, N->CalledFunctions); + } - // getAnalysisUsage - This obviously provides a call graph - virtual void getAnalysisUsage(AnalysisUsage &AU) const { - AU.setPreservesAll(); - AU.addProvided(ID); + /// \brief Adds a function to the list of functions called by this one. + void addCalledFunction(CallSite CS, CallGraphNode *M) { + assert(!CS.getInstruction() || !CS.getCalledFunction() || + !CS.getCalledFunction()->isIntrinsic()); + CalledFunctions.push_back(std::make_pair(CS.getInstruction(), M)); + M->AddRef(); } - // releaseMemory - Data structures can be large, so free memory aggressively. - virtual void releaseMemory() { - destroy(); + void removeCallEdge(iterator I) { + I->second->DropRef(); + *I = CalledFunctions.back(); + CalledFunctions.pop_back(); } + /// \brief 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); + + /// \brief 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); + + /// \brief Removes one edge associated with a null callsite from this node to + /// the specified callee function. + void removeOneAbstractEdgeTo(CallGraphNode *Callee); + + /// \brief Replaces the edge in the node for the specified call site with a + /// new one. + /// + /// Note that this method takes linear time, so it should be used sparingly. + void replaceCallEdge(CallSite CS, CallSite NewCS, CallGraphNode *NewNode); + private: - //===--------------------------------------------------------------------- - // Implementation of CallGraph construction - // + friend class CallGraph; - // getNodeFor - Return the node for the specified function or create one if it - // does not already exist. - // - CallGraphNode *getNodeFor(Function *F); + AssertingVH F; - // addToCallGraph - Add a function to the call graph, and link the node to all - // of the methods that it calls. - // - void addToCallGraph(Function *F); + std::vector CalledFunctions; + + /// \brief The number of times that this CallGraphNode occurs in the + /// CalledFunctions array of this or other CallGraphNodes. + unsigned NumReferences; - // destroy - Release memory for the call graph - void destroy(); + CallGraphNode(const CallGraphNode &) LLVM_DELETED_FUNCTION; + void operator=(const CallGraphNode &) LLVM_DELETED_FUNCTION; + + void DropRef() { --NumReferences; } + void AddRef() { ++NumReferences; } + + /// \brief A special function that should only be used by the CallGraph class. + void allReferencesDropped() { NumReferences = 0; } }; +/// \brief An analysis pass to compute the \c CallGraph for a \c Module. +/// +/// This class implements the concept of an analysis pass used by the \c +/// ModuleAnalysisManager to run an analysis over a module and cache the +/// resulting data. +class CallGraphAnalysis { +public: + /// \brief A formulaic typedef to inform clients of the result type. + typedef CallGraph Result; -//===----------------------------------------------------------------------===// -// CallGraphNode class definition -// -class CallGraphNode { - Function *Meth; - std::vector CalledMethods; + static void *ID() { return (void *)&PassID; } + + /// \brief Compute the \c CallGraph for the module \c M. + /// + /// The real work here is done in the \c CallGraph constructor. + CallGraph run(Module *M) { return CallGraph(*M); } + +private: + static char PassID; +}; + +/// \brief The \c ModulePass which wraps up a \c CallGraph and the logic to +/// build it. +/// +/// This class exposes both the interface to the call graph container and the +/// module pass which runs over a module of IR and produces the call graph. The +/// call graph interface is entirelly a wrapper around a \c CallGraph object +/// which is stored internally for each module. +class CallGraphWrapperPass : public ModulePass { + OwningPtr G; - CallGraphNode(const CallGraphNode &); // Do not implement public: - //===--------------------------------------------------------------------- - // Accessor methods... - // + static char ID; // Class identification, replacement for typeinfo - typedef std::vector::iterator iterator; - typedef std::vector::const_iterator const_iterator; + CallGraphWrapperPass(); + virtual ~CallGraphWrapperPass(); - // getMethod - Return the method that this call graph node represents... - Function *getMethod() const { return Meth; } + /// \brief The internal \c CallGraph around which the rest of this interface + /// is wrapped. + const CallGraph &getCallGraph() const { return *G; } + CallGraph &getCallGraph() { return *G; } - inline iterator begin() { return CalledMethods.begin(); } - inline iterator end() { return CalledMethods.end(); } - inline const_iterator begin() const { return CalledMethods.begin(); } - inline const_iterator end() const { return CalledMethods.end(); } - inline unsigned size() const { return CalledMethods.size(); } + typedef CallGraph::iterator iterator; + typedef CallGraph::const_iterator const_iterator; - // Subscripting operator - Return the i'th called method... - // - inline CallGraphNode *operator[](unsigned i) const { return CalledMethods[i];} + /// \brief Returns the module the call graph corresponds to. + Module &getModule() const { return G->getModule(); } + + inline iterator begin() { return G->begin(); } + inline iterator end() { return G->end(); } + inline const_iterator begin() const { return G->begin(); } + inline const_iterator end() const { return G->end(); } + + /// \brief Returns the call graph node for the provided function. + inline const CallGraphNode *operator[](const Function *F) const { + return (*G)[F]; + } + + /// \brief Returns the call graph node for the provided function. + inline CallGraphNode *operator[](const Function *F) { return (*G)[F]; } + + /// \brief Returns the \c CallGraphNode which is used to represent + /// undetermined calls into the callgraph. + CallGraphNode *getExternalCallingNode() const { + return G->getExternalCallingNode(); + } + CallGraphNode *getCallsExternalNode() const { + return G->getCallsExternalNode(); + } //===--------------------------------------------------------------------- - // Methods to keep a call graph up to date with a method that has been - // modified + // Functions to keep a call graph up to date with a function that has been + // modified. // - void removeAllCalledMethods() { - CalledMethods.clear(); + /// \brief 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) { + return G->removeFunctionFromModule(CGN); } -private: // Stuff to construct the node, used by CallGraph - friend class CallGraph; - - // CallGraphNode ctor - Create a node for the specified method... - inline CallGraphNode(Function *F) : Meth(F) {} - - // addCalledMethod add a method to the list of methods called by this one - void addCalledMethod(CallGraphNode *M) { - CalledMethods.push_back(M); + /// \brief Similar to operator[], but this will insert a new CallGraphNode for + /// \c F if one does not already exist. + CallGraphNode *getOrInsertFunction(const Function *F) { + return G->getOrInsertFunction(F); } -}; + //===--------------------------------------------------------------------- + // Implementation of the ModulePass interface needed here. + // + virtual void getAnalysisUsage(AnalysisUsage &AU) const; + virtual bool runOnModule(Module &M); + virtual void releaseMemory(); + + void print(raw_ostream &o, const Module *) const; + void dump() const; +}; //===----------------------------------------------------------------------===// // GraphTraits specializations for call graphs so that they can be treated as -// graphs by the generic graph algorithms... +// graphs by the generic graph algorithms. // // Provide graph traits for tranversing call graphs using standard graph // traversals. -template <> struct GraphTraits { +template <> struct GraphTraits { typedef CallGraphNode NodeType; - typedef NodeType::iterator ChildIteratorType; + + typedef CallGraphNode::CallRecord CGNPairTy; + typedef std::pointer_to_unary_function + CGNDerefFun; static NodeType *getEntryNode(CallGraphNode *CGN) { return CGN; } - static inline ChildIteratorType child_begin(NodeType *N) { return N->begin();} - static inline ChildIteratorType child_end (NodeType *N) { return N->end(); } + + typedef mapped_iterator 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 { +template <> struct GraphTraits { 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(); } + static inline ChildIteratorType child_begin(NodeType *N) { + return N->begin(); + } + static inline ChildIteratorType child_end(NodeType *N) { return N->end(); } }; - -template<> struct GraphTraits : - public GraphTraits { +template <> +struct GraphTraits : public GraphTraits { static NodeType *getEntryNode(CallGraph *CGN) { - return CGN->getRoot(); + return CGN->getExternalCallingNode(); // Start at the external node! + } + typedef std::pair PairTy; + typedef std::pointer_to_unary_function DerefFun; + + // nodes_iterator/begin/end - Allow iteration over all nodes in the graph + typedef mapped_iterator 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 : - public GraphTraits { + +template <> +struct GraphTraits : public GraphTraits< + const CallGraphNode *> { static NodeType *getEntryNode(const CallGraph *CGN) { - return CGN->getRoot(); + 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 -//===----------------------------------------------------------------------===// -// Printing support for Call Graphs -// - -// Stuff for printing out a callgraph... - -void WriteToOutput(const CallGraph &, std::ostream &o); -inline std::ostream &operator <<(std::ostream &o, const CallGraph &CG) { - WriteToOutput(CG, o); return o; -} - -void WriteToOutput(const CallGraphNode *, std::ostream &o); -inline std::ostream &operator <<(std::ostream &o, const CallGraphNode *CGN) { - WriteToOutput(CGN, o); return o; -} +// Make sure that any clients of this file link in CallGraph.cpp +FORCE_DEFINING_FILE_TO_BE_LINKED(CallGraph) #endif