// 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/Support/CallSite.h"
-#include "llvm/Support/Compiler.h"
-#include "llvm/Support/Streams.h"
-#include <ostream>
+#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;
-/// isOnlyADirectCall - Return true if this callsite is *just* a direct call to
-/// the specified function. Specifically return false if the callsite also
-/// takes the address of the function.
-static bool isOnlyADirectCall(Function *F, CallSite CS) {
- if (!CS.getInstruction()) return false;
- for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end(); I != E; ++I)
- if (*I == F) return false;
- return true;
-}
-
-namespace {
-
//===----------------------------------------------------------------------===//
-// BasicCallGraph class definition
+// Implementations of the CallGraph class methods.
//
-class VISIBILITY_HIDDEN BasicCallGraph : public CallGraph, public ModulePass {
- // 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((intptr_t)&ID), Root(0),
- ExternalCallingNode(0), CallsExternalNode(0) {}
-
- // 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();
- }
+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);
- void print(std::ostream *o, const Module *M) const {
- if (o) print(*o, M);
- }
+ // If we didn't find a main function, use the external call graph node
+ if (!Root)
+ Root = ExternalCallingNode;
+}
- virtual void print(std::ostream &o, const Module *M) const {
- o << "CallGraph Root is: ";
- if (Function *F = getRoot()->getFunction())
- o << F->getName() << "\n";
- else
- o << "<<null function: 0x" << getRoot() << ">>\n";
-
- CallGraph::print(o, M);
- }
+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
+}
- virtual void releaseMemory() {
- destroy();
- }
-
- /// dump - Print out this call graph.
- ///
- inline void dump() const {
- print(cerr, Mod);
- }
+void CallGraph::addToCallGraph(Function *F) {
+ CallGraphNode *Node = getOrInsertFunction(F);
- 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->hasInternalLinkage()) {
- 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 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 is not defined in this translation unit, it could call
- // anything.
- if (F->isDeclaration() && !F->isIntrinsic())
- Node->addCalledFunction(CallSite(), CallsExternalNode);
-
- // Loop over all of the users of the function... looking for callers...
- //
- bool isUsedExternally = false;
- for (Value::use_iterator I = F->use_begin(), E = F->use_end(); I != E; ++I){
- if (Instruction *Inst = dyn_cast<Instruction>(*I)) {
- CallSite CS = CallSite::get(Inst);
- if (isOnlyADirectCall(F, CS))
- getOrInsertFunction(Inst->getParent()->getParent())
- ->addCalledFunction(CS, Node);
- else
- isUsedExternally = true;
- } else if (GlobalValue *GV = dyn_cast<GlobalValue>(*I)) {
- for (Value::use_iterator I = GV->use_begin(), E = GV->use_end();
- I != E; ++I)
- if (Instruction *Inst = dyn_cast<Instruction>(*I)) {
- CallSite CS = CallSite::get(Inst);
- if (isOnlyADirectCall(F, CS))
- getOrInsertFunction(Inst->getParent()->getParent())
- ->addCalledFunction(CS, Node);
- else
- isUsedExternally = true;
- } else {
- isUsedExternally = true;
- }
- } else { // Can't classify the user!
- isUsedExternally = true;
+ // 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));
}
}
- if (isUsedExternally)
- ExternalCallingNode->addCalledFunction(CallSite(), Node);
-
- // Look for an indirect function call.
- 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 = CallSite::get(II);
- if (CS.getInstruction() && !CS.getCalledFunction())
- Node->addCalledFunction(CS, CallsExternalNode);
- }
- }
+}
- //
- // destroy - Release memory for the call graph
- virtual void destroy() {
- /// CallsExternalNode is not in the function map, delete it explicitly.
- delete CallsExternalNode;
- CallsExternalNode = 0;
- CallGraph::destroy();
+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";
}
-};
-RegisterAnalysisGroup<CallGraph> X("Call Graph");
-RegisterPass<BasicCallGraph> Y("basiccg", "Basic CallGraph Construction", false, true);
-RegisterAnalysisGroup<CallGraph, true> Z(Y);
+ // Print in a deterministic order by sorting CallGraphNodes by name. We do
+ // this here to avoid slowing down the non-printing fast path.
-} //End anonymous namespace
+ SmallVector<CallGraphNode *, 16> Nodes;
+ Nodes.reserve(FunctionMap.size());
-char CallGraph::ID = 0;
-char BasicCallGraph::ID = 0;
+ for (auto I = begin(), E = end(); I != E; ++I)
+ Nodes.push_back(I->second.get());
-void CallGraph::initialize(Module &M) {
- Mod = &M;
-}
+ 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();
-void CallGraph::destroy() {
- if (!FunctionMap.empty()) {
- for (FunctionMapTy::iterator I = FunctionMap.begin(), E = FunctionMap.end();
- I != E; ++I)
- delete I->second;
- FunctionMap.clear();
- }
-}
+ return RHS->getFunction() != nullptr;
+ });
-void CallGraph::print(std::ostream &OS, const Module *M) const {
- for (CallGraph::const_iterator I = begin(), E = end(); I != E; ++I)
- I->second->print(OS);
+ for (CallGraphNode *CN : Nodes)
+ CN->print(OS);
}
-void CallGraph::dump() const {
- print(cerr, 0);
-}
-
-//===----------------------------------------------------------------------===//
-// Implementations of public modification methods
-//
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+void CallGraph::dump() const { print(dbgs()); }
+#endif
// removeFunctionFromModule - Unlink the function from this module, returning
// it. Because this removes the function from the module, the call graph node
// is to dropAllReferences before calling this.
//
Function *CallGraph::removeFunctionFromModule(CallGraphNode *CGN) {
- assert(CGN->CalledFunctions.empty() && "Cannot remove function from call "
+ 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);
+ M.getFunctionList().remove(F);
return F;
}
-// changeFunction - This method changes the function associated with this
-// CallGraphNode, for use by transformations that need to change the prototype
-// of a Function (thus they must create a new Function and move the old code
-// over).
-void CallGraph::changeFunction(Function *OldF, Function *NewF) {
- iterator I = FunctionMap.find(OldF);
- CallGraphNode *&New = FunctionMap[NewF];
- assert(I != FunctionMap.end() && I->second && !New &&
- "OldF didn't exist in CG or NewF already does!");
- New = I->second;
- New->F = NewF;
+/// 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);
}
// 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));
+ 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();
}
-void CallGraphNode::print(std::ostream &OS) const {
+//===----------------------------------------------------------------------===//
+// Implementations of the CallGraphNode class methods.
+//
+
+void CallGraphNode::print(raw_ostream &OS) const {
if (Function *F = getFunction())
- OS << "Call graph node for function: '" << F->getName() <<"'\n";
+ OS << "Call graph node for function: '" << F->getName() << "'";
else
- OS << "Call graph node <<null function: 0x" << this << ">>:\n";
+ OS << "Call graph node <<null function>>";
+
+ OS << "<<" << this << ">> #uses=" << getNumReferences() << '\n';
- for (const_iterator I = begin(), E = end(); I != E; ++I)
- if (I->second->getFunction())
- OS << " Calls function '" << I->second->getFunction()->getName() <<"'\n";
- else
- OS << " Calls external node\n";
- OS << "\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';
}
-void CallGraphNode::dump() const { print(cerr); }
-
-void CallGraphNode::removeCallEdgeTo(CallGraphNode *Callee) {
- for (unsigned i = CalledFunctions.size(); ; --i) {
- assert(i && "Cannot find callee to remove!");
- if (CalledFunctions[i-1].second == Callee) {
- CalledFunctions.erase(CalledFunctions.begin()+i-1);
+#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;
}
}
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;
}
}
-// Enuse that users of CallGraph.h also link with this file
-DEFINING_FILE_FOR(CallGraph)
+/// 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() {}
+
+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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