-//===- CallGraph.cpp - Build a Module's call graph --------------------------=//
+//===- CallGraph.cpp - Build a Module's call graph ------------------------===//
//
-// This file implements call graph construction (from a module), and will
-// eventually implement call graph serialization and deserialization for
-// annotation support.
+// The LLVM Compiler Infrastructure
//
-// This call graph represents a dynamic method invocation as a null method node.
-// A call graph may only have up to one null method node that represents all of
-// the dynamic method invocations.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/CallGraph.h"
-#include "llvm/Analysis/Writer.h"
-#include "llvm/Module.h"
-#include "llvm/Method.h"
-#include "llvm/iOther.h"
-#include "llvm/iTerminators.h"
-#include "llvm/Support/InstIterator.h"// FIXME: CallGraph should use method uses
-#include "Support/STLExtras.h"
-#include <algorithm>
-
-AnalysisID cfg::CallGraph::ID(AnalysisID::create<cfg::CallGraph>());
-//AnalysisID cfg::CallGraph::ID(AnalysisID::template AnalysisID<cfg::CallGraph>());
-
-// getNodeFor - Return the node for the specified method or create one if it
-// does not already exist.
+#include "llvm/IR/CallSite.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+// Implementations of the CallGraph class methods.
//
-cfg::CallGraphNode *cfg::CallGraph::getNodeFor(Method *M) {
- iterator I = MethodMap.find(M);
- if (I != MethodMap.end()) return I->second;
- assert(M->getParent() == Mod && "Method not in current module!");
- CallGraphNode *New = new CallGraphNode(M);
+CallGraph::CallGraph(Module &M)
+ : M(M), Root(nullptr), ExternalCallingNode(getOrInsertFunction(nullptr)),
+ CallsExternalNode(llvm::make_unique<CallGraphNode>(nullptr)) {
+ // Add every function to the call graph.
+ for (Function &F : M)
+ addToCallGraph(&F);
- MethodMap.insert(std::make_pair(M, New));
- return New;
+ // If we didn't find a main function, use the external call graph node
+ if (!Root)
+ Root = ExternalCallingNode;
}
-// addToCallGraph - Add a method to the call graph, and link the node to all of
-// the methods that it calls.
-//
-void cfg::CallGraph::addToCallGraph(Method *M) {
- CallGraphNode *Node = getNodeFor(M);
-
- // If this method has external linkage,
- if (!M->hasInternalLinkage())
- Root->addCalledMethod(Node);
-
- for (inst_iterator I = inst_begin(M), E = inst_end(M); I != E; ++I) {
- // Dynamic calls will cause Null nodes to be created
- if (CallInst *CI = dyn_cast<CallInst>(*I))
- Node->addCalledMethod(getNodeFor(CI->getCalledMethod()));
- else if (InvokeInst *II = dyn_cast<InvokeInst>(*I))
- Node->addCalledMethod(getNodeFor(II->getCalledMethod()));
- }
+CallGraph::~CallGraph() {
+ // CallsExternalNode is not in the function map, delete it explicitly.
+ if (CallsExternalNode)
+ CallsExternalNode->allReferencesDropped();
+
+// Reset all node's use counts to zero before deleting them to prevent an
+// assertion from firing.
+#ifndef NDEBUG
+ for (auto &I : FunctionMap)
+ I.second->allReferencesDropped();
+#endif
}
-bool cfg::CallGraph::run(Module *TheModule) {
- destroy();
+void CallGraph::addToCallGraph(Function *F) {
+ CallGraphNode *Node = getOrInsertFunction(F);
- Mod = TheModule;
+ // If this function has external linkage, anything could call it.
+ if (!F->hasLocalLinkage()) {
+ ExternalCallingNode->addCalledFunction(CallSite(), Node);
- // Create the root node of the module...
- Root = new CallGraphNode(0);
+ // 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!
+ }
+ }
- // Add every method to the call graph...
- for_each(Mod->begin(), Mod->end(), bind_obj(this,&CallGraph::addToCallGraph));
-
- return false;
+ // 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.get());
+
+ // 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) {
+ const Function *Callee = CS.getCalledFunction();
+ if (!Callee || !Intrinsic::isLeaf(Callee->getIntrinsicID()))
+ // Indirect calls of intrinsics are not allowed so no need to check.
+ // We can be more precise here by using TargetArg returned by
+ // Intrinsic::isLeaf.
+ Node->addCalledFunction(CS, CallsExternalNode.get());
+ else if (!Callee->isIntrinsic())
+ Node->addCalledFunction(CS, getOrInsertFunction(Callee));
+ }
+ }
}
-void cfg::CallGraph::destroy() {
- for (MethodMapTy::iterator I = MethodMap.begin(), E = MethodMap.end();
- I != E; ++I) {
- delete I->second;
+void CallGraph::print(raw_ostream &OS) const {
+ OS << "CallGraph Root is: ";
+ if (Function *F = Root->getFunction())
+ OS << F->getName() << "\n";
+ else {
+ OS << "<<null function: 0x" << Root << ">>\n";
}
- MethodMap.clear();
+
+ // Print in a deterministic order by sorting CallGraphNodes by name. We do
+ // this here to avoid slowing down the non-printing fast path.
+
+ SmallVector<CallGraphNode *, 16> Nodes;
+ Nodes.reserve(FunctionMap.size());
+
+ for (auto I = begin(), E = end(); I != E; ++I)
+ Nodes.push_back(I->second.get());
+
+ std::sort(Nodes.begin(), Nodes.end(),
+ [](CallGraphNode *LHS, CallGraphNode *RHS) {
+ if (Function *LF = LHS->getFunction())
+ if (Function *RF = RHS->getFunction())
+ return LF->getName() < RF->getName();
+
+ return RHS->getFunction() != nullptr;
+ });
+
+ for (CallGraphNode *CN : Nodes)
+ CN->print(OS);
}
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+void CallGraph::dump() const { print(dbgs()); }
+#endif
-void cfg::WriteToOutput(const CallGraphNode *CGN, std::ostream &o) {
- if (CGN->getMethod())
- o << "Call graph node for method: '" << CGN->getMethod()->getName() <<"'\n";
- else
- o << "Call graph node null method:\n";
+// 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
+ FunctionMap.erase(F); // Remove the call graph node from the map
- for (unsigned i = 0; i < CGN->size(); ++i)
- o << " Calls method '" << (*CGN)[i]->getMethod()->getName() << "'\n";
- o << "\n";
+ M.getFunctionList().remove(F);
+ return F;
}
-void cfg::WriteToOutput(const CallGraph &CG, std::ostream &o) {
- WriteToOutput(CG.getRoot(), o);
- for (CallGraph::const_iterator I = CG.begin(), E = CG.end(); I != E; ++I)
- o << I->second;
+/// 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] = std::move(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) {
+ auto &CGN = FunctionMap[F];
+ if (CGN)
+ return CGN.get();
+
+ assert((!F || F->getParent() == &M) && "Function not in current module!");
+ CGN = llvm::make_unique<CallGraphNode>(const_cast<Function *>(F));
+ return CGN.get();
+}
//===----------------------------------------------------------------------===//
-// Implementations of public modification methods
+// Implementations of the CallGraphNode class methods.
//
-// Methods to keep a call graph up to date with a method that has been
-// modified
-//
-void cfg::CallGraph::addMethodToModule(Method *Meth) {
- assert(0 && "not implemented");
- abort();
+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';
}
-// removeMethodFromModule - Unlink the method from this module, returning it.
-// Because this removes the method from the module, the call graph node is
-// destroyed. This is only valid if the method does not call any other
-// methods (ie, there are no edges in it's CGN). The easiest way to do this
-// is to dropAllReferences before calling this.
-//
-Method *cfg::CallGraph::removeMethodFromModule(CallGraphNode *CGN) {
- assert(CGN->CalledMethods.empty() && "Cannot remove method from call graph"
- " if it references other methods!");
- Method *M = CGN->getMethod(); // Get the method for the call graph node
- delete CGN; // Delete the call graph node for this method
- MethodMap.erase(M); // Remove the call graph node from the map
-
- Mod->getMethodList().remove(M);
- return M;
-}
-
-
-//
-// Checks if a method contains any call instructions.
-// Note that this uses the call graph only if one is provided.
-// It does not build the call graph.
-//
-bool IsLeafMethod(const Method* M, const cfg::CallGraph* CG) {
- if (CG) {
- const cfg::CallGraphNode *cgn = (*CG)[M];
- return (cgn->begin() == cgn->end());
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+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 == nullptr) {
+ 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;
+ }
+ }
+}
+
+//===----------------------------------------------------------------------===//
+// Implementations of the CallGraphWrapperPass class methods.
+//
+
+CallGraphWrapperPass::CallGraphWrapperPass() : ModulePass(ID) {
+ initializeCallGraphWrapperPassPass(*PassRegistry::getPassRegistry());
+}
+
+CallGraphWrapperPass::~CallGraphWrapperPass() {}
- for (const_inst_iterator I = inst_begin(M), E = inst_end(M); I != E; ++I)
- if ((*I)->getOpcode() == Instruction::Call)
- return false;
- return true;
+void CallGraphWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesAll();
+}
+
+bool CallGraphWrapperPass::runOnModule(Module &M) {
+ // All the real work is done in the constructor for the CallGraph.
+ G.reset(new CallGraph(M));
+ return false;
}
+INITIALIZE_PASS(CallGraphWrapperPass, "basiccg", "CallGraph Construction",
+ false, true)
+
+char CallGraphWrapperPass::ID = 0;
+
+void CallGraphWrapperPass::releaseMemory() { G.reset(); }
+
+void CallGraphWrapperPass::print(raw_ostream &OS, const Module *) const {
+ if (!G) {
+ OS << "No call graph has been built!\n";
+ return;
+ }
+
+ // Just delegate.
+ G->print(OS);
+}
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+void CallGraphWrapperPass::dump() const { print(dbgs(), nullptr); }
+#endif
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