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For details, See: docs/2002-06-25-MegaPatchInfo.txt git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2779 91177308-0d34-0410-b5e6-96231b3b80d8
264 lines
9.4 KiB
C++
264 lines
9.4 KiB
C++
//===- CallGraph.h - Build a Module's call graph -----------------*- C++ -*--=//
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//
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// This interface is used to build and manipulate a call graph, which is a very
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// useful tool for interprocedural optimization.
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//
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// Every method in a module is represented as a node in the call graph. The
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// callgraph node keeps track of which methods the are called by the method
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// corresponding to the node.
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//
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// A call graph will contain nodes where the method that they correspond to is
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// null. This 'external' node is used to represent control flow that is not
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// represented (or analyzable) in the module. As such, the external node will
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// have edges to methods with the following properties:
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// 1. All methods in the module without internal linkage, since they could
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// be called by methods outside of the our analysis capability.
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// 2. All methods whose address is used for something more than a direct call,
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// for example being stored into a memory location. Since they may be
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// called by an unknown caller later, they must be tracked as such.
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//
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// Similarly, methods have a call edge to the external node iff:
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// 1. The method is external, reflecting the fact that they could call
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// anything without internal linkage or that has its address taken.
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// 2. The method contains an indirect method call.
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//
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// As an extension in the future, there may be multiple nodes with a null
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// method. These will be used when we can prove (through pointer analysis) that
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// an indirect call site can call only a specific set of methods.
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//
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// Because of these properties, the CallGraph captures a conservative superset
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// of all of the caller-callee relationships, which is useful for
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// transformations.
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//
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// The CallGraph class also attempts to figure out what the root of the
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// CallGraph is, which is currently does by looking for a method named 'main'.
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// If no method named 'main' is found, the external node is used as the entry
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// node, reflecting the fact that any method without internal linkage could
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// be called into (which is common for libraries).
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ANALYSIS_CALLGRAPH_H
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#define LLVM_ANALYSIS_CALLGRAPH_H
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#include "Support/GraphTraits.h"
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#include "llvm/Pass.h"
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class Function;
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class Module;
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class CallGraphNode;
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//===----------------------------------------------------------------------===//
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// CallGraph class definition
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//
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class CallGraph : public Pass {
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Module *Mod; // The module this call graph represents
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typedef std::map<const Function *, CallGraphNode *> MethodMapTy;
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MethodMapTy MethodMap; // Map from a method to its node
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// Root is root of the call graph, or the external node if a 'main' function
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// couldn't be found. ExternalNode is equivalent to (*this)[0].
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//
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CallGraphNode *Root, *ExternalNode;
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public:
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//===---------------------------------------------------------------------
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// Accessors...
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//
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typedef MethodMapTy::iterator iterator;
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typedef MethodMapTy::const_iterator const_iterator;
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inline CallGraphNode *getRoot() { return Root; }
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inline const CallGraphNode *getRoot() const { return Root; }
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inline iterator begin() { return MethodMap.begin(); }
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inline iterator end() { return MethodMap.end(); }
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inline const_iterator begin() const { return MethodMap.begin(); }
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inline const_iterator end() const { return MethodMap.end(); }
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// Subscripting operators, return the call graph node for the provided method
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inline const CallGraphNode *operator[](const Function *F) const {
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const_iterator I = MethodMap.find(F);
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assert(I != MethodMap.end() && "Method not in callgraph!");
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return I->second;
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}
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inline CallGraphNode *operator[](const Function *F) {
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const_iterator I = MethodMap.find(F);
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assert(I != MethodMap.end() && "Method not in callgraph!");
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return I->second;
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}
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//===---------------------------------------------------------------------
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// Methods to keep a call graph up to date with a method that has been
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// modified
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//
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void addMethodToModule(Function *Meth);
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// removeMethodFromModule - Unlink the method from this module, returning it.
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// Because this removes the method from the module, the call graph node is
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// destroyed. This is only valid if the method does not call any other
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// methods (ie, there are no edges in it's CGN). The easiest way to do this
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// is to dropAllReferences before calling this.
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//
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Function *removeMethodFromModule(CallGraphNode *CGN);
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Function *removeMethodFromModule(Function *Meth) {
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return removeMethodFromModule((*this)[Meth]);
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}
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//===---------------------------------------------------------------------
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// Pass infrastructure interface glue code...
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//
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static AnalysisID ID; // We are an analysis, we must have an ID
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CallGraph(AnalysisID AID) : Root(0) { assert(AID == ID); }
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~CallGraph() { destroy(); }
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virtual const char *getPassName() const { return "Call Graph Construction"; }
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// run - Compute the call graph for the specified module.
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virtual bool run(Module &M);
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// getAnalysisUsage - This obviously provides a call graph
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virtual void getAnalysisUsage(AnalysisUsage &AU) const {
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AU.setPreservesAll();
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AU.addProvided(ID);
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}
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// releaseMemory - Data structures can be large, so free memory aggressively.
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virtual void releaseMemory() {
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destroy();
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}
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private:
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//===---------------------------------------------------------------------
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// Implementation of CallGraph construction
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//
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// getNodeFor - Return the node for the specified function or create one if it
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// does not already exist.
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//
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CallGraphNode *getNodeFor(Function *F);
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// addToCallGraph - Add a function to the call graph, and link the node to all
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// of the methods that it calls.
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//
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void addToCallGraph(Function *F);
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// destroy - Release memory for the call graph
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void destroy();
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};
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//===----------------------------------------------------------------------===//
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// CallGraphNode class definition
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//
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class CallGraphNode {
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Function *Meth;
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std::vector<CallGraphNode*> CalledMethods;
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CallGraphNode(const CallGraphNode &); // Do not implement
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public:
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//===---------------------------------------------------------------------
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// Accessor methods...
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//
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typedef std::vector<CallGraphNode*>::iterator iterator;
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typedef std::vector<CallGraphNode*>::const_iterator const_iterator;
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// getMethod - Return the method that this call graph node represents...
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Function *getMethod() const { return Meth; }
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inline iterator begin() { return CalledMethods.begin(); }
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inline iterator end() { return CalledMethods.end(); }
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inline const_iterator begin() const { return CalledMethods.begin(); }
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inline const_iterator end() const { return CalledMethods.end(); }
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inline unsigned size() const { return CalledMethods.size(); }
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// Subscripting operator - Return the i'th called method...
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//
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inline CallGraphNode *operator[](unsigned i) const { return CalledMethods[i];}
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//===---------------------------------------------------------------------
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// Methods to keep a call graph up to date with a method that has been
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// modified
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//
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void removeAllCalledMethods() {
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CalledMethods.clear();
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}
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private: // Stuff to construct the node, used by CallGraph
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friend class CallGraph;
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// CallGraphNode ctor - Create a node for the specified method...
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inline CallGraphNode(Function *F) : Meth(F) {}
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// addCalledMethod add a method to the list of methods called by this one
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void addCalledMethod(CallGraphNode *M) {
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CalledMethods.push_back(M);
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}
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};
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//===----------------------------------------------------------------------===//
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// GraphTraits specializations for call graphs so that they can be treated as
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// graphs by the generic graph algorithms...
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//
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// Provide graph traits for tranversing call graphs using standard graph
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// traversals.
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template <> struct GraphTraits<CallGraphNode*> {
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typedef CallGraphNode NodeType;
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typedef NodeType::iterator ChildIteratorType;
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static NodeType *getEntryNode(CallGraphNode *CGN) { return CGN; }
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static inline ChildIteratorType child_begin(NodeType *N) { return N->begin();}
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static inline ChildIteratorType child_end (NodeType *N) { return N->end(); }
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};
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template <> struct GraphTraits<const CallGraphNode*> {
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typedef const CallGraphNode NodeType;
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typedef NodeType::const_iterator ChildIteratorType;
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static NodeType *getEntryNode(const CallGraphNode *CGN) { return CGN; }
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static inline ChildIteratorType child_begin(NodeType *N) { return N->begin();}
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static inline ChildIteratorType child_end (NodeType *N) { return N->end(); }
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};
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template<> struct GraphTraits<CallGraph*> :
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public GraphTraits<CallGraphNode*> {
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static NodeType *getEntryNode(CallGraph *CGN) {
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return CGN->getRoot();
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}
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};
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template<> struct GraphTraits<const CallGraph*> :
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public GraphTraits<const CallGraphNode*> {
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static NodeType *getEntryNode(const CallGraph *CGN) {
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return CGN->getRoot();
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}
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};
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//===----------------------------------------------------------------------===//
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// Printing support for Call Graphs
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//
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// Stuff for printing out a callgraph...
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void WriteToOutput(const CallGraph &, std::ostream &o);
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inline std::ostream &operator <<(std::ostream &o, const CallGraph &CG) {
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WriteToOutput(CG, o); return o;
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}
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void WriteToOutput(const CallGraphNode *, std::ostream &o);
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inline std::ostream &operator <<(std::ostream &o, const CallGraphNode *CGN) {
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WriteToOutput(CGN, o); return o;
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}
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#endif
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