/external/llvm/lib/Analysis/IPA/CallGraph.cpp
C++ | 337 lines | 209 code | 49 blank | 79 comment | 61 complexity | 9bcd58d2a1997b82b6c51c75cd997687 MD5 | raw file
- //===- CallGraph.cpp - Build a Module's call graph ------------------------===//
- //
- // The LLVM Compiler Infrastructure
- //
- // This file is distributed under the University of Illinois Open Source
- // License. See LICENSE.TXT for details.
- //
- //===----------------------------------------------------------------------===//
- //
- // This file implements the CallGraph class and provides the BasicCallGraph
- // default implementation.
- //
- //===----------------------------------------------------------------------===//
- #include "llvm/Analysis/CallGraph.h"
- #include "llvm/Module.h"
- #include "llvm/Instructions.h"
- #include "llvm/IntrinsicInst.h"
- #include "llvm/Support/CallSite.h"
- #include "llvm/Support/Debug.h"
- #include "llvm/Support/raw_ostream.h"
- using namespace llvm;
- namespace {
- //===----------------------------------------------------------------------===//
- // BasicCallGraph class definition
- //
- class BasicCallGraph : public ModulePass, public CallGraph {
- // Root is root of the call graph, or the external node if a 'main' function
- // couldn't be found.
- //
- 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:
- static char ID; // Class identification, replacement for typeinfo
- BasicCallGraph() : ModulePass(ID), Root(0),
- ExternalCallingNode(0), CallsExternalNode(0) {
- initializeBasicCallGraphPass(*PassRegistry::getPassRegistry());
- }
- // runOnModule - Compute the call graph for the specified module.
- virtual bool runOnModule(Module &M) {
- CallGraph::initialize(M);
-
- ExternalCallingNode = getOrInsertFunction(0);
- CallsExternalNode = new CallGraphNode(0);
- Root = 0;
-
- // Add every function to the call graph.
- for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
- addToCallGraph(I);
-
- // If we didn't find a main function, use the external call graph node
- if (Root == 0) Root = ExternalCallingNode;
-
- return false;
- }
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.setPreservesAll();
- }
- virtual void print(raw_ostream &OS, const Module *) const {
- OS << "CallGraph Root is: ";
- if (Function *F = getRoot()->getFunction())
- OS << F->getName() << "\n";
- else {
- OS << "<<null function: 0x" << getRoot() << ">>\n";
- }
-
- CallGraph::print(OS, 0);
- }
- virtual void releaseMemory() {
- destroy();
- }
-
- /// getAdjustedAnalysisPointer - This method is used when a pass implements
- /// an analysis interface through multiple inheritance. If needed, it should
- /// override this to adjust the this pointer as needed for the specified pass
- /// info.
- virtual void *getAdjustedAnalysisPointer(AnalysisID PI) {
- if (PI == &CallGraph::ID)
- return (CallGraph*)this;
- return this;
- }
-
- 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; }
- private:
- //===---------------------------------------------------------------------
- // Implementation of CallGraph construction
- //
- // addToCallGraph - Add a function to the call graph, and link the node to all
- // of the functions that it calls.
- //
- void addToCallGraph(Function *F) {
- CallGraphNode *Node = getOrInsertFunction(F);
- // If this function has external linkage, anything could call it.
- if (!F->hasLocalLinkage()) {
- ExternalCallingNode->addCalledFunction(CallSite(), Node);
- // Found the entry point?
- if (F->getName() == "main") {
- if (Root) // Found multiple external mains? Don't pick one.
- Root = ExternalCallingNode;
- else
- Root = Node; // Found a main, keep track of it!
- }
- }
- // If this function has its address taken, anything could call it.
- if (F->hasAddressTaken())
- ExternalCallingNode->addCalledFunction(CallSite(), Node);
- // If this function is not defined in this translation unit, it could call
- // anything.
- if (F->isDeclaration() && !F->isIntrinsic())
- Node->addCalledFunction(CallSite(), CallsExternalNode);
- // Look for calls by this function.
- for (Function::iterator BB = F->begin(), BBE = F->end(); BB != BBE; ++BB)
- for (BasicBlock::iterator II = BB->begin(), IE = BB->end();
- II != IE; ++II) {
- CallSite CS(cast<Value>(II));
- if (CS && !isa<IntrinsicInst>(II)) {
- const Function *Callee = CS.getCalledFunction();
- if (Callee)
- Node->addCalledFunction(CS, getOrInsertFunction(Callee));
- else
- Node->addCalledFunction(CS, CallsExternalNode);
- }
- }
- }
- //
- // destroy - Release memory for the call graph
- virtual void destroy() {
- /// CallsExternalNode is not in the function map, delete it explicitly.
- if (CallsExternalNode) {
- CallsExternalNode->allReferencesDropped();
- delete CallsExternalNode;
- CallsExternalNode = 0;
- }
- CallGraph::destroy();
- }
- };
- } //End anonymous namespace
- INITIALIZE_ANALYSIS_GROUP(CallGraph, "Call Graph", BasicCallGraph)
- INITIALIZE_AG_PASS(BasicCallGraph, CallGraph, "basiccg",
- "Basic CallGraph Construction", false, true, true)
- char CallGraph::ID = 0;
- char BasicCallGraph::ID = 0;
- void CallGraph::initialize(Module &M) {
- Mod = &M;
- }
- void CallGraph::destroy() {
- if (FunctionMap.empty()) return;
-
- // Reset all node's use counts to zero before deleting them to prevent an
- // assertion from firing.
- #ifndef NDEBUG
- for (FunctionMapTy::iterator I = FunctionMap.begin(), E = FunctionMap.end();
- I != E; ++I)
- I->second->allReferencesDropped();
- #endif
-
- for (FunctionMapTy::iterator I = FunctionMap.begin(), E = FunctionMap.end();
- I != E; ++I)
- delete I->second;
- FunctionMap.clear();
- }
- void CallGraph::print(raw_ostream &OS, Module*) const {
- for (CallGraph::const_iterator I = begin(), E = end(); I != E; ++I)
- I->second->print(OS);
- }
- #ifndef NDEBUG
- void CallGraph::dump() const {
- print(dbgs(), 0);
- }
- #endif
- //===----------------------------------------------------------------------===//
- // Implementations of public modification methods
- //
- // 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 *CallGraph::removeFunctionFromModule(CallGraphNode *CGN) {
- assert(CGN->empty() && "Cannot remove function from call "
- "graph if it references other functions!");
- Function *F = CGN->getFunction(); // Get the function for the call graph node
- delete CGN; // Delete the call graph node for this func
- FunctionMap.erase(F); // Remove the call graph node from the map
- Mod->getFunctionList().remove(F);
- return F;
- }
- /// spliceFunction - Replace the function represented by this node by another.
- /// This does not rescan the body of the function, so it is suitable when
- /// splicing the body of the old function to the new while also updating all
- /// callers from old to new.
- ///
- void CallGraph::spliceFunction(const Function *From, const Function *To) {
- assert(FunctionMap.count(From) && "No CallGraphNode for function!");
- assert(!FunctionMap.count(To) &&
- "Pointing CallGraphNode at a function that already exists");
- FunctionMapTy::iterator I = FunctionMap.find(From);
- I->second->F = const_cast<Function*>(To);
- FunctionMap[To] = I->second;
- FunctionMap.erase(I);
- }
- // getOrInsertFunction - This method is identical to calling operator[], but
- // it will insert a new CallGraphNode for the specified function if one does
- // not already exist.
- CallGraphNode *CallGraph::getOrInsertFunction(const Function *F) {
- CallGraphNode *&CGN = FunctionMap[F];
- if (CGN) return CGN;
-
- assert((!F || F->getParent() == Mod) && "Function not in current module!");
- return CGN = new CallGraphNode(const_cast<Function*>(F));
- }
- void CallGraphNode::print(raw_ostream &OS) const {
- if (Function *F = getFunction())
- OS << "Call graph node for function: '" << F->getName() << "'";
- else
- OS << "Call graph node <<null function>>";
-
- OS << "<<" << this << ">> #uses=" << getNumReferences() << '\n';
- for (const_iterator I = begin(), E = end(); I != E; ++I) {
- OS << " CS<" << I->first << "> calls ";
- if (Function *FI = I->second->getFunction())
- OS << "function '" << FI->getName() <<"'\n";
- else
- OS << "external node\n";
- }
- OS << '\n';
- }
- #ifndef NDEBUG
- void CallGraphNode::dump() const { print(dbgs()); }
- #endif
- /// removeCallEdgeFor - This method removes the edge in the node for the
- /// specified call site. Note that this method takes linear time, so it
- /// should be used sparingly.
- void CallGraphNode::removeCallEdgeFor(CallSite CS) {
- for (CalledFunctionsVector::iterator I = CalledFunctions.begin(); ; ++I) {
- assert(I != CalledFunctions.end() && "Cannot find callsite to remove!");
- if (I->first == CS.getInstruction()) {
- I->second->DropRef();
- *I = CalledFunctions.back();
- CalledFunctions.pop_back();
- return;
- }
- }
- }
- // 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 CallGraphNode::removeAnyCallEdgeTo(CallGraphNode *Callee) {
- for (unsigned i = 0, e = CalledFunctions.size(); i != e; ++i)
- if (CalledFunctions[i].second == Callee) {
- Callee->DropRef();
- CalledFunctions[i] = CalledFunctions.back();
- CalledFunctions.pop_back();
- --i; --e;
- }
- }
- /// removeOneAbstractEdgeTo - Remove one edge associated with a null callsite
- /// from this node to the specified callee function.
- void CallGraphNode::removeOneAbstractEdgeTo(CallGraphNode *Callee) {
- for (CalledFunctionsVector::iterator I = CalledFunctions.begin(); ; ++I) {
- assert(I != CalledFunctions.end() && "Cannot find callee to remove!");
- CallRecord &CR = *I;
- if (CR.second == Callee && CR.first == 0) {
- Callee->DropRef();
- *I = CalledFunctions.back();
- CalledFunctions.pop_back();
- return;
- }
- }
- }
- /// replaceCallEdge - This method replaces the edge in the node for the
- /// specified call site with a new one. Note that this method takes linear
- /// time, so it should be used sparingly.
- void CallGraphNode::replaceCallEdge(CallSite CS,
- CallSite NewCS, CallGraphNode *NewNode){
- for (CalledFunctionsVector::iterator I = CalledFunctions.begin(); ; ++I) {
- assert(I != CalledFunctions.end() && "Cannot find callsite to remove!");
- if (I->first == CS.getInstruction()) {
- I->second->DropRef();
- I->first = NewCS.getInstruction();
- I->second = NewNode;
- NewNode->AddRef();
- return;
- }
- }
- }
- // Enuse that users of CallGraph.h also link with this file
- DEFINING_FILE_FOR(CallGraph)