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diff --git a/llvm/lib/Analysis/CallGraph.cpp b/llvm/lib/Analysis/CallGraph.cpp
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+++ b/llvm/lib/Analysis/CallGraph.cpp
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+//===- CallGraph.cpp - Build a Module's call graph ------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/CallGraph.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Config/llvm-config.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/PassManager.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
+#include <cassert>
+
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+// Implementations of the CallGraph class methods.
+//
+
+CallGraph::CallGraph(Module &M)
+    : M(M), ExternalCallingNode(getOrInsertFunction(nullptr)),
+      CallsExternalNode(std::make_unique<CallGraphNode>(nullptr)) {
+  // Add every function to the call graph.
+  for (Function &F : M)
+    addToCallGraph(&F);
+}
+
+CallGraph::CallGraph(CallGraph &&Arg)
+    : M(Arg.M), FunctionMap(std::move(Arg.FunctionMap)),
+      ExternalCallingNode(Arg.ExternalCallingNode),
+      CallsExternalNode(std::move(Arg.CallsExternalNode)) {
+  Arg.FunctionMap.clear();
+  Arg.ExternalCallingNode = nullptr;
+}
+
+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
+}
+
+void CallGraph::addToCallGraph(Function *F) {
+  CallGraphNode *Node = getOrInsertFunction(F);
+
+  // If this function has external linkage or has its address taken, anything
+  // could call it.
+  if (!F->hasLocalLinkage() || F->hasAddressTaken())
+    ExternalCallingNode->addCalledFunction(nullptr, Node);
+
+  // If this function is not defined in this translation unit, it could call
+  // anything.
+  if (F->isDeclaration() && !F->isIntrinsic())
+    Node->addCalledFunction(nullptr, CallsExternalNode.get());
+
+  // Look for calls by this function.
+  for (BasicBlock &BB : *F)
+    for (Instruction &I : BB) {
+      if (auto *Call = dyn_cast<CallBase>(&I)) {
+        const Function *Callee = Call->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(Call, CallsExternalNode.get());
+        else if (!Callee->isIntrinsic())
+          Node->addCalledFunction(Call, getOrInsertFunction(Callee));
+      }
+    }
+}
+
+void CallGraph::print(raw_ostream &OS) const {
+  // 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 (const auto &I : *this)
+    Nodes.push_back(I.second.get());
+
+  llvm::sort(Nodes, [](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)
+LLVM_DUMP_METHOD 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 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
+
+  M.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] = 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 = std::make_unique<CallGraphNode>(const_cast<Function *>(F));
+  return CGN.get();
+}
+
+//===----------------------------------------------------------------------===//
+// 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() << "'";
+  else
+    OS << "Call graph node <<null function>>";
+
+  OS << "<<" << this << ">>  #uses=" << getNumReferences() << '\n';
+
+  for (const auto &I : *this) {
+    OS << "  CS<" << I.first << "> calls ";
+    if (Function *FI = I.second->getFunction())
+      OS << "function '" << FI->getName() <<"'\n";
+    else
+      OS << "external node\n";
+  }
+  OS << '\n';
+}
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+LLVM_DUMP_METHOD 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(CallBase &Call) {
+  for (CalledFunctionsVector::iterator I = CalledFunctions.begin(); ; ++I) {
+    assert(I != CalledFunctions.end() && "Cannot find callsite to remove!");
+    if (I->first == &Call) {
+      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(CallBase &Call, CallBase &NewCall,
+                                    CallGraphNode *NewNode) {
+  for (CalledFunctionsVector::iterator I = CalledFunctions.begin(); ; ++I) {
+    assert(I != CalledFunctions.end() && "Cannot find callsite to remove!");
+    if (I->first == &Call) {
+      I->second->DropRef();
+      I->first = &NewCall;
+      I->second = NewNode;
+      NewNode->AddRef();
+      return;
+    }
+  }
+}
+
+// Provide an explicit template instantiation for the static ID.
+AnalysisKey CallGraphAnalysis::Key;
+
+PreservedAnalyses CallGraphPrinterPass::run(Module &M,
+                                            ModuleAnalysisManager &AM) {
+  AM.getResult<CallGraphAnalysis>(M).print(OS);
+  return PreservedAnalyses::all();
+}
+
+//===----------------------------------------------------------------------===//
+// Out-of-line definitions of CallGraphAnalysis class members.
+//
+
+//===----------------------------------------------------------------------===//
+// Implementations of the CallGraphWrapperPass class methods.
+//
+
+CallGraphWrapperPass::CallGraphWrapperPass() : ModulePass(ID) {
+  initializeCallGraphWrapperPassPass(*PassRegistry::getPassRegistry());
+}
+
+CallGraphWrapperPass::~CallGraphWrapperPass() = default;
+
+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)
+LLVM_DUMP_METHOD
+void CallGraphWrapperPass::dump() const { print(dbgs(), nullptr); }
+#endif
+
+namespace {
+
+struct CallGraphPrinterLegacyPass : public ModulePass {
+  static char ID; // Pass ID, replacement for typeid
+
+  CallGraphPrinterLegacyPass() : ModulePass(ID) {
+    initializeCallGraphPrinterLegacyPassPass(*PassRegistry::getPassRegistry());
+  }
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.setPreservesAll();
+    AU.addRequiredTransitive<CallGraphWrapperPass>();
+  }
+
+  bool runOnModule(Module &M) override {
+    getAnalysis<CallGraphWrapperPass>().print(errs(), &M);
+    return false;
+  }
+};
+
+} // end anonymous namespace
+
+char CallGraphPrinterLegacyPass::ID = 0;
+
+INITIALIZE_PASS_BEGIN(CallGraphPrinterLegacyPass, "print-callgraph",
+                      "Print a call graph", true, true)
+INITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass)
+INITIALIZE_PASS_END(CallGraphPrinterLegacyPass, "print-callgraph",
+                    "Print a call graph", true, true)