-//===- 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
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and 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 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
+// 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 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.
+// 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.
//
-// Similarly, methods have a call edge to the external node iff:
-// 1. The method is external, reflecting the fact that they could call
+// 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 method contains an indirect method call.
+// 2. The function contains an indirect function 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.
+// 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 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
+// 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/STLExtras.h"
#include "llvm/Pass.h"
+
+namespace llvm {
+
class Function;
class Module;
class CallGraphNode;
//===----------------------------------------------------------------------===//
// CallGraph class definition
//
-class CallGraph : public Pass {
+class CallGraph {
+protected:
Module *Mod; // The module this call graph represents
- typedef std::map<const Function *, CallGraphNode *> MethodMapTy;
- MethodMapTy MethodMap; // Map from a method to its node
+ 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. ExternalNode is equivalent to (*this)[0].
- //
- CallGraphNode *Root, *ExternalNode;
public:
-
//===---------------------------------------------------------------------
// Accessors...
//
- typedef MethodMapTy::iterator iterator;
- typedef MethodMapTy::const_iterator const_iterator;
+ 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(); }
+ /// 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 method
+ // Subscripting operators, return 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;
}
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;
}
+ //Returns the CallGraphNode which is used to represent undetermined calls
+ // into the callgraph. Override this if you want behavioural 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 behavioural
+ // inheritance.
+ virtual CallGraphNode* getRoot() { return 0; }
+ virtual const CallGraphNode* getRoot() const { return 0; }
+
//===---------------------------------------------------------------------
- // 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);
-
- // 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]);
+ /// 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);
//===---------------------------------------------------------------------
// Pass infrastructure interface glue code...
//
- 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"; }
-
- // run - Compute the call graph for the specified module.
- virtual bool run(Module *TheModule);
-
- // getAnalysisUsage - This obviously provides a call graph
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.setPreservesAll();
- AU.addProvided(ID);
- }
-
- // releaseMemory - Data structures can be large, so free memory agressively.
- virtual void releaseMemory() {
- destroy();
- }
-
-private:
- //===---------------------------------------------------------------------
- // Implementation of CallGraph construction
- //
+protected:
+ CallGraph() {}
+
+public:
+ virtual ~CallGraph() { destroy(); }
- // getNodeFor - Return the node for the specified function or create one if it
- // does not already exist.
- //
- CallGraphNode *getNodeFor(Function *F);
+ /// initialize - Call this method before calling other methods,
+ /// re/initializes the state of the CallGraph.
+ ///
+ void initialize(Module &M);
- // addToCallGraph - Add a function to the call graph, and link the node to all
- // of the methods that it calls.
- //
- void addToCallGraph(Function *F);
+ virtual void print(std::ostream &o, const Module *M) const;
+ void dump() const;
+
+ // stub - dummy function, just ignore it
+ static void stub();
+protected:
// destroy - Release memory for the call graph
- void destroy();
+ virtual void destroy();
};
-
//===----------------------------------------------------------------------===//
// CallGraphNode class definition
//
class CallGraphNode {
- Function *Meth;
- std::vector<CallGraphNode*> CalledMethods;
+ Function *F;
+ std::vector<CallGraphNode*> CalledFunctions;
CallGraphNode(const CallGraphNode &); // Do not implement
public:
typedef std::vector<CallGraphNode*>::iterator iterator;
typedef std::vector<CallGraphNode*>::const_iterator const_iterator;
- // getMethod - Return the method that this call graph node represents...
- Function *getMethod() const { return Meth; }
+ // getFunction - Return the function that this call graph node represents...
+ Function *getFunction() const { return F; }
- 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(); }
+ 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 unsigned size() const { return CalledFunctions.size(); }
- // Subscripting operator - Return the i'th called method...
+ // Subscripting operator - Return the i'th called function...
//
- inline CallGraphNode *operator[](unsigned i) const { return CalledMethods[i];}
+ CallGraphNode *operator[](unsigned i) const { return CalledFunctions[i];}
+ /// dump - Print out this call graph node.
+ ///
+ void dump() const;
+ void print(std::ostream &OS) const;
//===---------------------------------------------------------------------
- // Methods to keep a call graph up to date with a method that has been
+ // Methods to keep a call graph up to date with a function that has been
// modified
//
- void removeAllCalledMethods() {
- CalledMethods.clear();
+ /// removeAllCalledFunctions - As the name implies, this removes all edges
+ /// from this CallGraphNode to any functions it calls.
+ void removeAllCalledFunctions() {
+ CalledFunctions.clear();
}
-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);
+ /// addCalledFunction add a function to the list of functions called by this
+ /// one.
+ void addCalledFunction(CallGraphNode *M) {
+ CalledFunctions.push_back(M);
}
-};
+ /// removeCallEdgeTo - This method removes a *single* edge to the specified
+ /// callee function. Note that this method takes linear time, so it should be
+ /// used sparingly.
+ void removeCallEdgeTo(CallGraphNode *Callee);
+
+ /// removeAnyCallEdgeTo - This method removes any 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);
+
+ 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
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->getRoot();
+ 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 (std::pair<const Function*,
+ CallGraphNode*> P) {
+ return *P.second;
}
};
+
template<> struct GraphTraits<const CallGraph*> :
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(); }
};
+// Make sure that any clients of this file link in CallGraph.cpp
+static IncludeFile
+CALLGRAPH_INCLUDE_FILE((void*)&CallGraph::stub);
-//===----------------------------------------------------------------------===//
-// Printing support for Call Graphs
-//
-
-// Stuff for printing out a callgraph...
+extern void BasicCallGraphStub();
+static IncludeFile HDR_INCLUDE_CALLGRAPH_CPP((void*)&BasicCallGraphStub);
-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;
-}
+} // End llvm namespace
#endif
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