-//===- 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.
// 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 function 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 functions with the following properties:
-// 1. All functions in the module without internal linkage, since they could
-// be called by functions outside of the our analysis capability.
+// 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. Since they may
-// be called by an unknown caller later, they must be tracked as such.
+// 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, functions have a call edge to the external node iff:
+// 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.
// transformations.
//
// The CallGraph class also attempts to figure out what the root of the
-// CallGraph is, which is currently does by looking for a function named 'main'.
+// 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).
#include "Support/GraphTraits.h"
#include "Support/STLExtras.h"
#include "llvm/Pass.h"
+
+namespace llvm {
+
class Function;
class Module;
class CallGraphNode;
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].
+ // couldn't be found.
//
- CallGraphNode *Root, *ExternalNode;
+ CallGraphNode *Root;
+
+ // ExternalCallingNode - 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.
+ CallGraphNode *CallsExternalNode;
+
public:
//===---------------------------------------------------------------------
typedef FunctionMapTy::iterator iterator;
typedef FunctionMapTy::const_iterator const_iterator;
- // getExternalNode - Return the node that points to all functions that are
- // accessable from outside of the current program.
- //
- CallGraphNode *getExternalNode() { return ExternalNode; }
- const CallGraphNode *getExternalNode() const { return ExternalNode; }
+ 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; }
+ /// 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(); }
// Functions to keep a call graph up to date with a function that has been
// modified
//
- void addFunctionToModule(Function *Meth);
+ void addFunctionToModule(Function *F);
// removeFunctionFromModule - Unlink the function from this module, returning
// is to dropAllReferences before calling this.
//
Function *removeFunctionFromModule(CallGraphNode *CGN);
- Function *removeFunctionFromModule(Function *Meth) {
- return removeFunctionFromModule((*this)[Meth]);
+ Function *removeFunctionFromModule(Function *F) {
+ return removeFunctionFromModule((*this)[F]);
}
///
void print(std::ostream &o, const Module *M) const;
+ // stub - dummy function, just ignore it
+ static void stub();
private:
//===---------------------------------------------------------------------
// Implementation of CallGraph construction
// CallGraphNode class definition
//
class CallGraphNode {
- Function *Meth;
+ Function *F;
std::vector<CallGraphNode*> CalledFunctions;
CallGraphNode(const CallGraphNode &); // Do not implement
typedef std::vector<CallGraphNode*>::const_iterator const_iterator;
// getFunction - Return the function that this call graph node represents...
- Function *getFunction() const { return Meth; }
+ Function *getFunction() const { return F; }
inline iterator begin() { return CalledFunctions.begin(); }
inline iterator end() { return CalledFunctions.end(); }
CalledFunctions.clear();
}
-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) : Meth(F) {}
-
// addCalledFunction add a function to the list of functions called by this
// one
void addCalledFunction(CallGraphNode *M) {
CalledFunctions.push_back(M);
}
+
+ void removeCallEdgeTo(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) {}
};
template<> struct GraphTraits<CallGraph*> : public GraphTraits<CallGraphNode*> {
static NodeType *getEntryNode(CallGraph *CGN) {
- return CGN->getExternalNode(); // 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;
template<> struct GraphTraits<const CallGraph*> :
public GraphTraits<const CallGraphNode*> {
static NodeType *getEntryNode(const CallGraph *CGN) {
- return CGN->getExternalNode();
+ 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_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);
+
+} // End llvm namespace
+
#endif
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