forked from OSchip/llvm-project
300 lines
10 KiB
C++
300 lines
10 KiB
C++
//===- CallGraph.cpp - Build a Module's call graph ------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the CallGraph class and provides the BasicCallGraph
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// default implementation.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/CallGraph.h"
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#include "llvm/Module.h"
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#include "llvm/Instructions.h"
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#include "llvm/IntrinsicInst.h"
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#include "llvm/Support/CallSite.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace llvm;
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namespace {
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//===----------------------------------------------------------------------===//
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// BasicCallGraph class definition
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//
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class BasicCallGraph : public CallGraph, public ModulePass {
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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.
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//
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CallGraphNode *Root;
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// ExternalCallingNode - This node has edges to all external functions and
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// those internal functions that have their address taken.
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CallGraphNode *ExternalCallingNode;
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// CallsExternalNode - This node has edges to it from all functions making
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// indirect calls or calling an external function.
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CallGraphNode *CallsExternalNode;
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public:
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static char ID; // Class identification, replacement for typeinfo
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BasicCallGraph() : ModulePass(&ID), Root(0),
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ExternalCallingNode(0), CallsExternalNode(0) {}
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// runOnModule - Compute the call graph for the specified module.
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virtual bool runOnModule(Module &M) {
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CallGraph::initialize(M);
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ExternalCallingNode = getOrInsertFunction(0);
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CallsExternalNode = new CallGraphNode(0);
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Root = 0;
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// Add every function to the call graph.
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for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
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addToCallGraph(I);
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// If we didn't find a main function, use the external call graph node
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if (Root == 0) Root = ExternalCallingNode;
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return false;
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}
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virtual void getAnalysisUsage(AnalysisUsage &AU) const {
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AU.setPreservesAll();
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}
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virtual void print(raw_ostream &OS, const Module *) const {
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OS << "CallGraph Root is: ";
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if (Function *F = getRoot()->getFunction())
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OS << F->getName() << "\n";
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else {
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OS << "<<null function: 0x" << getRoot() << ">>\n";
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}
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CallGraph::print(OS, 0);
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}
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virtual void releaseMemory() {
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destroy();
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}
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CallGraphNode* getExternalCallingNode() const { return ExternalCallingNode; }
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CallGraphNode* getCallsExternalNode() const { return CallsExternalNode; }
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// getRoot - Return the root of the call graph, which is either main, or if
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// main cannot be found, the external node.
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//
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CallGraphNode *getRoot() { return Root; }
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const CallGraphNode *getRoot() const { return Root; }
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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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// addToCallGraph - Add a function to the call graph, and link the node to all
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// of the functions that it calls.
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//
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void addToCallGraph(Function *F) {
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CallGraphNode *Node = getOrInsertFunction(F);
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// If this function has external linkage, anything could call it.
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if (!F->hasLocalLinkage()) {
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ExternalCallingNode->addCalledFunction(CallSite(), Node);
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// Found the entry point?
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if (F->getName() == "main") {
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if (Root) // Found multiple external mains? Don't pick one.
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Root = ExternalCallingNode;
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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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}
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// Loop over all of the users of the function, looking for non-call uses.
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for (Value::use_iterator I = F->use_begin(), E = F->use_end(); I != E; ++I)
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if ((!isa<CallInst>(I) && !isa<InvokeInst>(I))
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|| !CallSite(cast<Instruction>(I)).isCallee(I)) {
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// Not a call, or being used as a parameter rather than as the callee.
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ExternalCallingNode->addCalledFunction(CallSite(), Node);
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break;
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}
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// If this function is not defined in this translation unit, it could call
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// anything.
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if (F->isDeclaration() && !F->isIntrinsic())
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Node->addCalledFunction(CallSite(), CallsExternalNode);
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// Look for calls by this function.
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for (Function::iterator BB = F->begin(), BBE = F->end(); BB != BBE; ++BB)
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for (BasicBlock::iterator II = BB->begin(), IE = BB->end();
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II != IE; ++II) {
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CallSite CS = CallSite::get(II);
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if (CS.getInstruction() && !isa<DbgInfoIntrinsic>(II)) {
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const Function *Callee = CS.getCalledFunction();
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if (Callee)
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Node->addCalledFunction(CS, getOrInsertFunction(Callee));
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else
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Node->addCalledFunction(CS, CallsExternalNode);
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}
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}
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}
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//
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// destroy - Release memory for the call graph
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virtual void destroy() {
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/// CallsExternalNode is not in the function map, delete it explicitly.
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delete CallsExternalNode;
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CallsExternalNode = 0;
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CallGraph::destroy();
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}
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};
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} //End anonymous namespace
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static RegisterAnalysisGroup<CallGraph> X("Call Graph");
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static RegisterPass<BasicCallGraph>
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Y("basiccg", "Basic CallGraph Construction", false, true);
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static RegisterAnalysisGroup<CallGraph, true> Z(Y);
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char CallGraph::ID = 0;
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char BasicCallGraph::ID = 0;
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void CallGraph::initialize(Module &M) {
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Mod = &M;
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}
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void CallGraph::destroy() {
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if (FunctionMap.empty()) return;
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for (FunctionMapTy::iterator I = FunctionMap.begin(), E = FunctionMap.end();
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I != E; ++I)
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delete I->second;
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FunctionMap.clear();
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}
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void CallGraph::print(raw_ostream &OS, Module*) const {
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for (CallGraph::const_iterator I = begin(), E = end(); I != E; ++I)
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I->second->print(OS);
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}
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void CallGraph::dump() const {
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print(errs(), 0);
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}
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//===----------------------------------------------------------------------===//
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// Implementations of public modification methods
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//
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// removeFunctionFromModule - Unlink the function from this module, returning
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// it. Because this removes the function from the module, the call graph node
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// is destroyed. This is only valid if the function does not call any other
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// functions (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 *CallGraph::removeFunctionFromModule(CallGraphNode *CGN) {
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assert(CGN->empty() && "Cannot remove function from call "
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"graph if it references other functions!");
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Function *F = CGN->getFunction(); // Get the function for the call graph node
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delete CGN; // Delete the call graph node for this func
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FunctionMap.erase(F); // Remove the call graph node from the map
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Mod->getFunctionList().remove(F);
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return F;
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}
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// getOrInsertFunction - This method is identical to calling operator[], but
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// it will insert a new CallGraphNode for the specified function if one does
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// not already exist.
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CallGraphNode *CallGraph::getOrInsertFunction(const Function *F) {
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CallGraphNode *&CGN = FunctionMap[F];
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if (CGN) return CGN;
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assert((!F || F->getParent() == Mod) && "Function not in current module!");
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return CGN = new CallGraphNode(const_cast<Function*>(F));
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}
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void CallGraphNode::print(raw_ostream &OS) const {
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if (Function *F = getFunction())
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OS << "Call graph node for function: '" << F->getName() << "'";
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else
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OS << "Call graph node <<null function>>";
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OS << "<<0x" << this << ">> #uses=" << getNumReferences() << '\n';
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for (const_iterator I = begin(), E = end(); I != E; ++I)
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if (Function *FI = I->second->getFunction())
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OS << " Calls function '" << FI->getName() <<"'\n";
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else
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OS << " Calls external node\n";
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OS << "\n";
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}
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void CallGraphNode::dump() const { print(errs()); }
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/// removeCallEdgeFor - This method removes the edge in the node for the
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/// specified call site. Note that this method takes linear time, so it
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/// should be used sparingly.
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void CallGraphNode::removeCallEdgeFor(CallSite CS) {
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for (CalledFunctionsVector::iterator I = CalledFunctions.begin(); ; ++I) {
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assert(I != CalledFunctions.end() && "Cannot find callsite to remove!");
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if (I->first == CS.getInstruction()) {
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I->second->DropRef();
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*I = CalledFunctions.back();
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CalledFunctions.pop_back();
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return;
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}
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}
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}
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// removeAnyCallEdgeTo - This method removes any call edges from this node to
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// the specified callee function. This takes more time to execute than
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// removeCallEdgeTo, so it should not be used unless necessary.
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void CallGraphNode::removeAnyCallEdgeTo(CallGraphNode *Callee) {
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for (unsigned i = 0, e = CalledFunctions.size(); i != e; ++i)
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if (CalledFunctions[i].second == Callee) {
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Callee->DropRef();
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CalledFunctions[i] = CalledFunctions.back();
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CalledFunctions.pop_back();
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--i; --e;
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}
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}
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/// removeOneAbstractEdgeTo - Remove one edge associated with a null callsite
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/// from this node to the specified callee function.
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void CallGraphNode::removeOneAbstractEdgeTo(CallGraphNode *Callee) {
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for (CalledFunctionsVector::iterator I = CalledFunctions.begin(); ; ++I) {
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assert(I != CalledFunctions.end() && "Cannot find callee to remove!");
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CallRecord &CR = *I;
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if (CR.second == Callee && CR.first == 0) {
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Callee->DropRef();
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*I = CalledFunctions.back();
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CalledFunctions.pop_back();
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return;
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}
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}
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}
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/// replaceCallEdge - This method replaces the edge in the node for the
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/// specified call site with a new one. Note that this method takes linear
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/// time, so it should be used sparingly.
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void CallGraphNode::replaceCallEdge(CallSite CS,
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CallSite NewCS, CallGraphNode *NewNode){
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for (CalledFunctionsVector::iterator I = CalledFunctions.begin(); ; ++I) {
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assert(I != CalledFunctions.end() && "Cannot find callsite to remove!");
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if (I->first == CS.getInstruction()) {
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I->second->DropRef();
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I->first = NewCS.getInstruction();
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I->second = NewNode;
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NewNode->AddRef();
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return;
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}
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}
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}
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// Enuse that users of CallGraph.h also link with this file
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DEFINING_FILE_FOR(CallGraph)
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