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Diffstat (limited to 'include/llvm/Analysis/CallGraph.h')
| -rw-r--r-- | include/llvm/Analysis/CallGraph.h | 454 |
1 files changed, 271 insertions, 183 deletions
diff --git a/include/llvm/Analysis/CallGraph.h b/include/llvm/Analysis/CallGraph.h index d00c2ed..9a6a4a7 100644 --- a/include/llvm/Analysis/CallGraph.h +++ b/include/llvm/Analysis/CallGraph.h @@ -6,46 +6,47 @@ // 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). -// +/// \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 @@ -53,11 +54,11 @@ #include "llvm/ADT/GraphTraits.h" #include "llvm/ADT/STLExtras.h" +#include "llvm/IR/CallSite.h" #include "llvm/IR/Function.h" +#include "llvm/IR/ValueHandle.h" #include "llvm/Pass.h" -#include "llvm/Support/CallSite.h" #include "llvm/Support/IncludeFile.h" -#include "llvm/Support/ValueHandle.h" #include <map> namespace llvm { @@ -66,171 +67,142 @@ class Function; class Module; class CallGraphNode; -//===----------------------------------------------------------------------===// -// CallGraph class definition -// -class CallGraph : public ModulePass { - 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<const Function *, CallGraphNode *> FunctionMapTy; - FunctionMapTy FunctionMap; // Map from a function to its node - // Root is root of the call graph, or the external node if a 'main' function - // couldn't be found. - // + /// \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; - // ExternalCallingNode - This node has edges to all external functions and - // those internal functions that have their address taken. + /// \brief This node has edges to all external functions and those internal + /// functions that have their address taken. CallGraphNode *ExternalCallingNode; - // CallsExternalNode - This node has edges to it from all functions making - // indirect calls or calling an external function. + /// \brief This node has edges to it from all functions making indirect calls + /// or calling an external function. CallGraphNode *CallsExternalNode; - /// Replace the function represented by this node by another. + /// \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); - // Add a function to the call graph, and link the node to all of the functions - // that it calls. + /// \brief Add a function to the call graph, and link the node to all of the + /// functions that it calls. void addToCallGraph(Function *F); public: - static char ID; // Class identification, replacement for typeinfo - //===--------------------------------------------------------------------- - // Accessors. - // + CallGraph(Module &M); + ~CallGraph(); + + void print(raw_ostream &OS) const; + void dump() const; + typedef FunctionMapTy::iterator iterator; typedef FunctionMapTy::const_iterator const_iterator; - /// getModule - Return the module the call graph corresponds to. - /// - Module &getModule() const { return *Mod; } + /// \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 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(); } + inline const_iterator end() const { return FunctionMap.end(); } - // Subscripting operators, return the call graph node for the provided - // function + /// \brief Returns 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; } + + /// \brief Returns the call graph node for the provided function. 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. + /// \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; } - /// Return the root/main method in the module, or some other root node, such - /// as the externalcallingnode. - CallGraphNode *getRoot() { return Root; } - const CallGraphNode *getRoot() const { return Root; } + CallGraphNode *getCallsExternalNode() const { return CallsExternalNode; } //===--------------------------------------------------------------------- // 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. + /// \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); - /// 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. + /// \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); - - CallGraph(); - virtual ~CallGraph() { releaseMemory(); } - 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; }; -//===----------------------------------------------------------------------===// -// CallGraphNode class definition. -// +/// \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 { - friend class CallGraph; - - AssertingVH<Function> F; - - // CallRecord - This is a pair of the calling instruction (a call or invoke) - // and the callgraph node being called. public: - typedef std::pair<WeakVH, CallGraphNode*> CallRecord; -private: - std::vector<CallRecord> CalledFunctions; - - /// NumReferences - This is the number of times that this CallGraphNode occurs - /// in the CalledFunctions array of this or other CallGraphNodes. - unsigned NumReferences; + /// \brief A pair of the calling instruction (a call or invoke) + /// and the call graph node being called. + typedef std::pair<WeakVH, CallGraphNode *> CallRecord; - CallGraphNode(const CallGraphNode &) LLVM_DELETED_FUNCTION; - void operator=(const CallGraphNode &) LLVM_DELETED_FUNCTION; - - void DropRef() { --NumReferences; } - void AddRef() { ++NumReferences; } public: typedef std::vector<CallRecord> CalledFunctionsVector; - - // CallGraphNode ctor - Create a node for the specified function. - inline CallGraphNode(Function *f) : F(f), NumReferences(0) {} + /// \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"); } - - //===--------------------------------------------------------------------- - // 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. + /// \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 iterator end() { return CalledFunctions.end(); } inline const_iterator begin() const { return CalledFunctions.begin(); } - inline const_iterator end() const { return CalledFunctions.end(); } + inline const_iterator end() const { return CalledFunctions.end(); } inline bool empty() const { return CalledFunctions.empty(); } inline unsigned size() const { return (unsigned)CalledFunctions.size(); } - /// getNumReferences - Return the number of other CallGraphNodes in this - /// CallGraph that reference this node in their callee list. + /// \brief Returns the number of other CallGraphNodes in this CallGraph that + /// reference this node in their callee list. unsigned getNumReferences() const { return NumReferences; } - - // Subscripting operator - Return the i'th called function. - // + + /// \brief Returns the i'th called function. CallGraphNode *operator[](unsigned i) const { assert(i < CalledFunctions.size() && "Invalid index"); return CalledFunctions[i].second; } - /// dump - Print out this call graph node. - /// + /// \brief Print out this call graph node. void dump() const; void print(raw_ostream &OS) const; @@ -239,29 +211,25 @@ public: // modified // - /// removeAllCalledFunctions - As the name implies, this removes all edges - /// from this CallGraphNode to any functions it calls. + /// \brief Removes all edges from this CallGraphNode to any functions it + /// calls. void removeAllCalledFunctions() { while (!CalledFunctions.empty()) { CalledFunctions.back().second->DropRef(); CalledFunctions.pop_back(); } } - - /// stealCalledFunctionsFrom - Move all the callee information from N to this - /// node. + + /// \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); } - - /// addCalledFunction - Add a function to the list of functions called by this - /// one. + /// \brief Adds a function to the list of functions called by this one. void addCalledFunction(CallSite CS, CallGraphNode *M) { - assert(!CS.getInstruction() || - !CS.getCalledFunction() || + assert(!CS.getInstruction() || !CS.getCalledFunction() || !CS.getCalledFunction()->isIntrinsic()); CalledFunctions.push_back(std::make_pair(CS.getInstruction(), M)); M->AddRef(); @@ -272,32 +240,152 @@ public: *I = CalledFunctions.back(); CalledFunctions.pop_back(); } - - - /// 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. + + /// \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); - /// 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. + /// \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); - /// removeOneAbstractEdgeTo - Remove one edge associated with a null callsite - /// from this node to the specified callee function. + /// \brief Removes one edge associated with a null callsite from this node to + /// the specified callee function. void removeOneAbstractEdgeTo(CallGraphNode *Callee); - - /// replaceCallEdge - This method 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. + + /// \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); - - /// allReferencesDropped - This is a special function that should only be - /// used by the CallGraph class. - void allReferencesDropped() { - NumReferences = 0; + +private: + friend class CallGraph; + + AssertingVH<Function> F; + + std::vector<CallRecord> CalledFunctions; + + /// \brief The number of times that this CallGraphNode occurs in the + /// CalledFunctions array of this or other CallGraphNodes. + unsigned NumReferences; + + 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; + + 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 { + std::unique_ptr<CallGraph> G; + +public: + static char ID; // Class identification, replacement for typeinfo + + CallGraphWrapperPass(); + virtual ~CallGraphWrapperPass(); + + /// \brief The internal \c CallGraph around which the rest of this interface + /// is wrapped. + const CallGraph &getCallGraph() const { return *G; } + CallGraph &getCallGraph() { return *G; } + + typedef CallGraph::iterator iterator; + typedef CallGraph::const_iterator const_iterator; + + /// \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(); + } + + //===--------------------------------------------------------------------- + // Functions to keep a call graph up to date with a function that has been + // modified. + // + + /// \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); + } + + /// \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. + // + + void getAnalysisUsage(AnalysisUsage &AU) const override; + bool runOnModule(Module &M) override; + void releaseMemory() override; + + void print(raw_ostream &o, const Module *) const override; + void dump() const; }; //===----------------------------------------------------------------------===// @@ -307,11 +395,12 @@ public: // Provide graph traits for tranversing call graphs using standard graph // traversals. -template <> struct GraphTraits<CallGraphNode*> { +template <> struct GraphTraits<CallGraphNode *> { typedef CallGraphNode NodeType; typedef CallGraphNode::CallRecord CGNPairTy; - typedef std::pointer_to_unary_function<CGNPairTy, CallGraphNode*> CGNDerefFun; + typedef std::pointer_to_unary_function<CGNPairTy, CallGraphNode *> + CGNDerefFun; static NodeType *getEntryNode(CallGraphNode *CGN) { return CGN; } @@ -320,55 +409,54 @@ template <> struct GraphTraits<CallGraphNode*> { static inline ChildIteratorType child_begin(NodeType *N) { return map_iterator(N->begin(), CGNDerefFun(CGNDeref)); } - static inline ChildIteratorType child_end (NodeType *N) { + static inline ChildIteratorType child_end(NodeType *N) { return map_iterator(N->end(), CGNDerefFun(CGNDeref)); } - static CallGraphNode *CGNDeref(CGNPairTy P) { - return P.second; - } - + static CallGraphNode *CGNDeref(CGNPairTy P) { return P.second; } }; -template <> struct GraphTraits<const CallGraphNode*> { +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(); } + 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*> { +template <> +struct GraphTraits<CallGraph *> : public GraphTraits<CallGraphNode *> { static NodeType *getEntryNode(CallGraph *CGN) { - return CGN->getExternalCallingNode(); // Start at the external node! + return CGN->getExternalCallingNode(); // Start at the external node! } - typedef std::pair<const Function*, CallGraphNode*> PairTy; - typedef std::pointer_to_unary_function<PairTy, CallGraphNode&> DerefFun; + 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) { + static nodes_iterator nodes_end(CallGraph *CG) { return map_iterator(CG->end(), DerefFun(CGdereference)); } - static CallGraphNode &CGdereference(PairTy P) { - return *P.second; - } + static CallGraphNode &CGdereference(PairTy P) { return *P.second; } }; -template<> struct GraphTraits<const CallGraph*> : - public GraphTraits<const CallGraphNode*> { +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(); } + static nodes_iterator nodes_end(const CallGraph *CG) { return CG->end(); } }; } // End llvm namespace |