-//===- llvm/Analysis/CallGraph.h - Build a Module's call graph ---*- C++ -*--=//
+//===- CallGraph.h - Build a Module's call graph ----------------*- C++ -*-===//
+//
+// 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.
//
-// This call graph represents a dynamic method invocation as a null method node.
-// A call graph may only have up to one null method node that represents all of
-// the dynamic method invocations.
+// 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.
//
-// Additionally, the 'root' node of a call graph represents the "entry point"
-// node of the graph, which has an edge to every external method in the graph.
-// This node has a null method pointer.
+// 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/Support/GraphTraits.h"
-#include <map>
-#include <vector>
-class Method;
-class Module;
+#include "llvm/ADT/GraphTraits.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Pass.h"
-namespace cfg {
+namespace llvm {
-class CallGraph;
-class CallGraphNode {
- Method *Meth;
- vector<CallGraphNode*> CalledMethods;
+class Function;
+class Module;
+class CallGraphNode;
- CallGraphNode(const CallGraphNode &); // Do not implement
-public:
- typedef vector<CallGraphNode*>::iterator iterator;
- typedef vector<CallGraphNode*>::const_iterator const_iterator;
+//===----------------------------------------------------------------------===//
+// CallGraph class definition
+//
+class CallGraph : public ModulePass {
+ Module *Mod; // The module this call graph represents
- // getMethod - Return the method that this call graph node represents...
- Method *getMethod() const { return Meth; }
+ typedef std::map<const Function *, CallGraphNode *> FunctionMapTy;
+ FunctionMapTy FunctionMap; // Map from a function to its node
- 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(); }
+ // Root is root of the call graph, or the external node if a 'main' function
+ // couldn't be found.
+ //
+ CallGraphNode *Root;
- inline CallGraphNode *operator[](unsigned i) const { return CalledMethods[i];}
+ // ExternalCallingNode - This node has edges to all external functions and
+ // those internal functions that have their address taken.
+ CallGraphNode *ExternalCallingNode;
- void removeAllCalledMethods() {
- CalledMethods.clear();
- }
+ // CallsExternalNode - This node has edges to it from all functions making
+ // indirect calls or calling an external function.
+ CallGraphNode *CallsExternalNode;
-private: // Stuff to construct the node, used by CallGraph
- friend class CallGraph;
+public:
+ //===---------------------------------------------------------------------
+ // Accessors...
+ //
+ typedef FunctionMapTy::iterator iterator;
+ typedef FunctionMapTy::const_iterator const_iterator;
- // CallGraphNode ctor - Create a node for the specified method...
- inline CallGraphNode(Method *M) : Meth(M) {}
-
- // addCalledMethod add a method to the list of methods called by this one
- void addCalledMethod(CallGraphNode *M) {
- CalledMethods.push_back(M);
- }
-};
+ CallGraphNode *getExternalCallingNode() const { return ExternalCallingNode; }
+ CallGraphNode *getCallsExternalNode() const { return CallsExternalNode; }
+ // getRoot - Return the root of the call graph, which is either main, or if
+ // main cannot be found, the external node.
+ //
+ CallGraphNode *getRoot() { return Root; }
+ const CallGraphNode *getRoot() const { return Root; }
-class CallGraph {
- Module *Mod; // The module this call graph represents
+ /// getModule - Return the module the call graph corresponds to.
+ ///
+ Module &getModule() const { return *Mod; }
- typedef map<const Method *, CallGraphNode *> MethodMapTy;
- MethodMapTy MethodMap; // Map from a method to its node
+ 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(); }
- CallGraphNode *Root;
-public:
- CallGraph(Module *TheModule);
- ~CallGraph();
-
- typedef MethodMapTy::iterator iterator;
- typedef MethodMapTy::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(); }
-
- inline const CallGraphNode *operator[](const Method *M) const {
- const_iterator I = MethodMap.find(M);
- assert(I != MethodMap.end() && "Method not in callgraph!");
+
+ // 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 Method *M) {
- const_iterator I = MethodMap.find(M);
- assert(I != MethodMap.end() && "Method not in callgraph!");
+ inline CallGraphNode *operator[](const Function *F) {
+ const_iterator I = FunctionMap.find(F);
+ assert(I != FunctionMap.end() && "Function not in callgraph!");
return I->second;
}
- // 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(Method *Meth); // TODO IMPLEMENT
+ /// 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);
- // 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.
+ //===---------------------------------------------------------------------
+ // Pass infrastructure interface glue code...
//
- Method *removeMethodFromModule(CallGraphNode *CGN);
- Method *removeMethodFromModule(Method *Meth) {
- return removeMethodFromModule((*this)[Meth]);
+ CallGraph() : Root(0), CallsExternalNode(0) {}
+ ~CallGraph() { destroy(); }
+
+ // runOnModule - Compute the call graph for the specified module.
+ virtual bool runOnModule(Module &M);
+
+ // getAnalysisUsage - This obviously provides a call graph
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesAll();
+ }
+
+ // releaseMemory - Data structures can be large, so free memory aggressively.
+ virtual void releaseMemory() {
+ destroy();
}
-private: // Implementation of CallGraph construction
+ /// Print the types found in the module. If the optional Module parameter is
+ /// passed in, then the types are printed symbolically if possible, using the
+ /// symbol table from the module.
+ ///
+ void print(std::ostream &o, const Module *M) const;
+
+ /// dump - Print out this call graph.
+ ///
+ void dump() const;
+
+ // stub - dummy function, just ignore it
+ static void stub();
+private:
+ //===---------------------------------------------------------------------
+ // Implementation of CallGraph construction
+ //
- // getNodeFor - Return the node for the specified method or create one if it
+ // getNodeFor - Return the node for the specified function or create one if it
// does not already exist.
//
- CallGraphNode *getNodeFor(Method *M);
+ CallGraphNode *getNodeFor(Function *F);
- // addToCallGraph - Add a method to the call graph, and link the node to all
- // of the methods that it calls.
+ // addToCallGraph - Add a function to the call graph, and link the node to all
+ // of the functions that it calls.
//
- void addToCallGraph(Method *M);
+ void addToCallGraph(Function *F);
+
+ // destroy - Release memory for the call graph
+ void destroy();
};
-} // end namespace cfg
+//===----------------------------------------------------------------------===//
+// CallGraphNode class definition
+//
+class CallGraphNode {
+ Function *F;
+ std::vector<CallGraphNode*> CalledFunctions;
+
+ CallGraphNode(const CallGraphNode &); // Do not implement
+public:
+ //===---------------------------------------------------------------------
+ // Accessor methods...
+ //
+
+ typedef std::vector<CallGraphNode*>::iterator iterator;
+ typedef std::vector<CallGraphNode*>::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 unsigned size() const { return CalledFunctions.size(); }
+
+ // Subscripting operator - Return the i'th called function...
+ //
+ 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 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(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);
+
+private: // Stuff to construct the node, used by CallGraph
+ 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<cfg::CallGraphNode*> {
- typedef cfg::CallGraphNode NodeType;
+template <> struct GraphTraits<CallGraphNode*> {
+ typedef CallGraphNode NodeType;
typedef NodeType::iterator ChildIteratorType;
- static NodeType *getEntryNode(cfg::CallGraphNode *CGN) { return CGN; }
+ 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(); }
};
-template <> struct GraphTraits<const cfg::CallGraphNode*> {
- typedef const cfg::CallGraphNode NodeType;
+template <> struct GraphTraits<const CallGraphNode*> {
+ typedef const CallGraphNode NodeType;
typedef NodeType::const_iterator ChildIteratorType;
- static NodeType *getEntryNode(const cfg::CallGraphNode *CGN) { return CGN; }
+ 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;
-template<> struct GraphTraits<cfg::CallGraph*> :
- public GraphTraits<cfg::CallGraphNode*> {
- static NodeType *getEntryNode(cfg::CallGraph *CGN) {
- return CGN->getRoot();
+ // 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 cfg::CallGraph*> :
- public GraphTraits<const cfg::CallGraphNode*> {
- static NodeType *getEntryNode(const cfg::CallGraph *CGN) {
- return CGN->getRoot();
+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(); }
};
+// Make sure that any clients of this file link in PostDominators.cpp
+static IncludeFile
+CALLGRAPH_INCLUDE_FILE((void*)&CallGraph::stub);
-// Checks if a method contains any call instructions.
-// Note that this uses the call graph only if one is provided.
-// It does not build the call graph.
-//
-bool isLeafMethod(const Method* method, const cfg::CallGraph *callGraph = 0);
+} // End llvm namespace
#endif