Clean up call graph, add comments, and fix test/Regression/Other/2002-01-31-CallGraph.ll
llvm-svn: 1828
This commit is contained in:
Chris Lattner
parent
46519418b0
commit
beed742b55
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@ -1,15 +1,40 @@
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//===- llvm/Analysis/CallGraph.h - Build a Module's call graph ---*- C++ -*--=//
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//===- CallGraph.cpp - Build a Module's call graph ------------------------===//
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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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// This call graph represents a dynamic method invocation as a null method node.
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// A call graph may only have up to one null method node that represents all of
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// the dynamic method invocations.
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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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// Additionally, the 'root' node of a call graph represents the "entry point"
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// node of the graph, which has an edge to every external method in the graph.
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// This node has a null method pointer.
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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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@ -20,7 +45,110 @@
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#include "llvm/Pass.h"
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class Method;
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class Module;
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class CallGraph;
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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 Method *, 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 Method *M) const {
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const_iterator I = MethodMap.find(M);
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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 Method *M) {
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const_iterator I = MethodMap.find(M);
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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(Method *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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Method *removeMethodFromModule(CallGraphNode *CGN);
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Method *removeMethodFromModule(Method *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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// run - Compute the call graph for the specified module.
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virtual bool run(Module *TheModule);
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// getAnalysisUsageInfo - This obviously provides a call graph
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virtual void getAnalysisUsageInfo(AnalysisSet &Required,
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AnalysisSet &Destroyed,
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AnalysisSet &Provided) {
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Provided.push_back(ID);
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}
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// releaseMemory - Data structures can be large, so free memory agressively.
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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 method or create one if it
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// does not already exist.
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//
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CallGraphNode *getNodeFor(Method *M);
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// addToCallGraph - Add a method 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(Method *M);
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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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@ -31,6 +159,10 @@ class CallGraphNode {
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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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@ -43,8 +175,16 @@ public:
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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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@ -62,89 +202,6 @@ private: // Stuff to construct the node, used by CallGraph
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};
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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 Method *, CallGraphNode *> MethodMapTy;
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MethodMapTy MethodMap; // Map from a method to its node
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CallGraphNode *Root;
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public:
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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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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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inline const CallGraphNode *operator[](const Method *M) const {
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const_iterator I = MethodMap.find(M);
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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 Method *M) {
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const_iterator I = MethodMap.find(M);
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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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// 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(Method *Meth); // TODO IMPLEMENT
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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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Method *removeMethodFromModule(CallGraphNode *CGN);
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Method *removeMethodFromModule(Method *Meth) {
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return removeMethodFromModule((*this)[Meth]);
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}
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// run - Compute the call graph for the specified module.
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virtual bool run(Module *TheModule);
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// getAnalysisUsageInfo - This obviously provides a call graph
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virtual void getAnalysisUsageInfo(AnalysisSet &Required,
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AnalysisSet &Destroyed,
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AnalysisSet &Provided) {
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Provided.push_back(ID);
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}
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// releaseMemory - Data structures can be large, so free memory agressively.
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virtual void releaseMemory() {
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destroy();
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}
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private: // Implementation of CallGraph construction
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void destroy();
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// getNodeFor - Return the node for the specified method or create one if it
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// does not already exist.
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//
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CallGraphNode *getNodeFor(Method *M);
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// addToCallGraph - Add a method 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(Method *M);
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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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@ -1,12 +1,40 @@
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//===- CallGraph.cpp - Build a Module's call graph ------------------------===//
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//
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// This file implements call graph construction (from a module), and will
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// eventually implement call graph serialization and deserialization for
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// annotation support.
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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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// This call graph represents a dynamic method invocation as a null method node.
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// A call graph may only have up to one null method node that represents all of
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// the dynamic method invocations.
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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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@ -15,7 +43,6 @@
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#include "llvm/Method.h"
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#include "llvm/iOther.h"
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#include "llvm/iTerminators.h"
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#include "llvm/Support/InstIterator.h"// FIXME: CallGraph should use method uses
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#include "Support/STLExtras.h"
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#include <algorithm>
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#include <iostream>
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@ -26,14 +53,11 @@ AnalysisID CallGraph::ID(AnalysisID::create<CallGraph>());
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// does not already exist.
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//
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CallGraphNode *CallGraph::getNodeFor(Method *M) {
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iterator I = MethodMap.find(M);
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if (I != MethodMap.end()) return I->second;
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CallGraphNode *&CGN = MethodMap[M];
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if (CGN) return CGN;
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assert(M->getParent() == Mod && "Method not in current module!");
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CallGraphNode *New = new CallGraphNode(M);
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MethodMap.insert(std::make_pair(M, New));
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return New;
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assert((!M || M->getParent() == Mod) && "Method not in current module!");
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return CGN = new CallGraphNode(M);
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}
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// addToCallGraph - Add a method to the call graph, and link the node to all of
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@ -43,15 +67,46 @@ void CallGraph::addToCallGraph(Method *M) {
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CallGraphNode *Node = getNodeFor(M);
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// If this method has external linkage,
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if (!M->hasInternalLinkage())
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Root->addCalledMethod(Node);
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if (!M->hasInternalLinkage()) {
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ExternalNode->addCalledMethod(Node);
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for (inst_iterator I = inst_begin(M), E = inst_end(M); I != E; ++I) {
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// Dynamic calls will cause Null nodes to be created
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if (CallInst *CI = dyn_cast<CallInst>(*I))
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Node->addCalledMethod(getNodeFor(CI->getCalledMethod()));
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else if (InvokeInst *II = dyn_cast<InvokeInst>(*I))
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Node->addCalledMethod(getNodeFor(II->getCalledMethod()));
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// Found the entry point?
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if (M->getName() == "main") {
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if (Root)
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Root = ExternalNode; // Found multiple external mains? Don't pick one.
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else
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Root = Node; // Found a main, keep track of it!
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}
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} else if (M->isExternal()) { // Not defined in this xlation unit?
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Node->addCalledMethod(ExternalNode); // It could call anything...
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}
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// Loop over all of the users of the method... looking for callers...
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//
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for (Value::use_iterator I = M->use_begin(), E = M->use_end(); I != E; ++I) {
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User *U = *I;
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if (CallInst *CI = dyn_cast<CallInst>(U))
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getNodeFor(CI->getParent()->getParent())->addCalledMethod(Node);
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else if (InvokeInst *II = dyn_cast<InvokeInst>(U))
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getNodeFor(II->getParent()->getParent())->addCalledMethod(Node);
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else // Can't classify the user!
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ExternalNode->addCalledMethod(Node);
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}
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// Look for an indirect method call...
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for (Method::iterator BBI = M->begin(), BBE = M->end(); BBI != BBE; ++BBI) {
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BasicBlock *BB = *BBI;
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for (BasicBlock::iterator II = BB->begin(), IE = BB->end(); II != IE; ++II){
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Instruction *I = *II;
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if (CallInst *CI = dyn_cast<CallInst>(I)) {
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if (CI->getCalledMethod() == 0)
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Node->addCalledMethod(ExternalNode);
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} else if (InvokeInst *II = dyn_cast<InvokeInst>(I)) {
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if (II->getCalledMethod() == 0)
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Node->addCalledMethod(ExternalNode);
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}
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}
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}
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}
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@ -59,21 +114,22 @@ bool CallGraph::run(Module *TheModule) {
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destroy();
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Mod = TheModule;
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// Create the root node of the module...
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Root = new CallGraphNode(0);
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ExternalNode = getNodeFor(0);
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Root = 0;
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// Add every method to the call graph...
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for_each(Mod->begin(), Mod->end(), bind_obj(this,&CallGraph::addToCallGraph));
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// If we didn't find a main method, use the external call graph node
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if (Root == 0) Root = ExternalNode;
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return false;
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}
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void CallGraph::destroy() {
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for (MethodMapTy::iterator I = MethodMap.begin(), E = MethodMap.end();
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I != E; ++I) {
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I != E; ++I)
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delete I->second;
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}
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MethodMap.clear();
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}
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@ -85,12 +141,14 @@ void WriteToOutput(const CallGraphNode *CGN, std::ostream &o) {
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o << "Call graph node null method:\n";
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for (unsigned i = 0; i < CGN->size(); ++i)
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o << " Calls method '" << (*CGN)[i]->getMethod()->getName() << "'\n";
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if ((*CGN)[i]->getMethod())
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o << " Calls method '" << (*CGN)[i]->getMethod()->getName() << "'\n";
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else
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o << " Calls external node\n";
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o << "\n";
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}
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void WriteToOutput(const CallGraph &CG, std::ostream &o) {
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WriteToOutput(CG.getRoot(), o);
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for (CallGraph::const_iterator I = CG.begin(), E = CG.end(); I != E; ++I)
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o << I->second;
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}
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