Intermediate changes

commit_hash:2ec2671384dd8e604d41bc5c52c2f7858e4afea6

1 files changed, 0 insertions, 2050 deletions

diff --git a/contrib/libs/llvm14/lib/Analysis/LazyCallGraph.cpp b/contrib/libs/llvm14/lib/Analysis/LazyCallGraph.cpp
deleted file mode 100644
index e8e9593d703..00000000000
--- a/contrib/libs/llvm14/lib/Analysis/LazyCallGraph.cpp
+++ /dev/null
@@ -1,2050 +0,0 @@
-//===- LazyCallGraph.cpp - Analysis of 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/LazyCallGraph.h"
-#include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/ScopeExit.h"
-#include "llvm/ADT/Sequence.h"
-#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/iterator_range.h"
-#include "llvm/Analysis/TargetLibraryInfo.h"
-#include "llvm/Analysis/VectorUtils.h"
-#include "llvm/Config/llvm-config.h"
-#include "llvm/IR/Function.h"
-#include "llvm/IR/GlobalVariable.h"
-#include "llvm/IR/InstIterator.h"
-#include "llvm/IR/Instruction.h"
-#include "llvm/IR/Module.h"
-#include "llvm/IR/PassManager.h"
-#include "llvm/Support/Casting.h"
-#include "llvm/Support/Compiler.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/GraphWriter.h"
-#include "llvm/Support/raw_ostream.h"
-#include <algorithm>
-#include <cassert>
-#include <cstddef>
-#include <iterator>
-#include <string>
-#include <tuple>
-#include <utility>
-
-using namespace llvm;
-
-#define DEBUG_TYPE "lcg"
-
-void LazyCallGraph::EdgeSequence::insertEdgeInternal(Node &TargetN,
-                                                     Edge::Kind EK) {
-  EdgeIndexMap.insert({&TargetN, Edges.size()});
-  Edges.emplace_back(TargetN, EK);
-}
-
-void LazyCallGraph::EdgeSequence::setEdgeKind(Node &TargetN, Edge::Kind EK) {
-  Edges[EdgeIndexMap.find(&TargetN)->second].setKind(EK);
-}
-
-bool LazyCallGraph::EdgeSequence::removeEdgeInternal(Node &TargetN) {
-  auto IndexMapI = EdgeIndexMap.find(&TargetN);
-  if (IndexMapI == EdgeIndexMap.end())
-    return false;
-
-  Edges[IndexMapI->second] = Edge();
-  EdgeIndexMap.erase(IndexMapI);
-  return true;
-}
-
-static void addEdge(SmallVectorImpl<LazyCallGraph::Edge> &Edges,
-                    DenseMap<LazyCallGraph::Node *, int> &EdgeIndexMap,
-                    LazyCallGraph::Node &N, LazyCallGraph::Edge::Kind EK) {
-  if (!EdgeIndexMap.insert({&N, Edges.size()}).second)
-    return;
-
-  LLVM_DEBUG(dbgs() << "    Added callable function: " << N.getName() << "\n");
-  Edges.emplace_back(LazyCallGraph::Edge(N, EK));
-}
-
-LazyCallGraph::EdgeSequence &LazyCallGraph::Node::populateSlow() {
-  assert(!Edges && "Must not have already populated the edges for this node!");
-
-  LLVM_DEBUG(dbgs() << "  Adding functions called by '" << getName()
-                    << "' to the graph.\n");
-
-  Edges = EdgeSequence();
-
-  SmallVector<Constant *, 16> Worklist;
-  SmallPtrSet<Function *, 4> Callees;
-  SmallPtrSet<Constant *, 16> Visited;
-
-  // Find all the potential call graph edges in this function. We track both
-  // actual call edges and indirect references to functions. The direct calls
-  // are trivially added, but to accumulate the latter we walk the instructions
-  // and add every operand which is a constant to the worklist to process
-  // afterward.
-  //
-  // Note that we consider *any* function with a definition to be a viable
-  // edge. Even if the function's definition is subject to replacement by
-  // some other module (say, a weak definition) there may still be
-  // optimizations which essentially speculate based on the definition and
-  // a way to check that the specific definition is in fact the one being
-  // used. For example, this could be done by moving the weak definition to
-  // a strong (internal) definition and making the weak definition be an
-  // alias. Then a test of the address of the weak function against the new
-  // strong definition's address would be an effective way to determine the
-  // safety of optimizing a direct call edge.
-  for (BasicBlock &BB : *F)
-    for (Instruction &I : BB) {
-      if (auto *CB = dyn_cast<CallBase>(&I))
-        if (Function *Callee = CB->getCalledFunction())
-          if (!Callee->isDeclaration())
-            if (Callees.insert(Callee).second) {
-              Visited.insert(Callee);
-              addEdge(Edges->Edges, Edges->EdgeIndexMap, G->get(*Callee),
-                      LazyCallGraph::Edge::Call);
-            }
-
-      for (Value *Op : I.operand_values())
-        if (Constant *C = dyn_cast<Constant>(Op))
-          if (Visited.insert(C).second)
-            Worklist.push_back(C);
-    }
-
-  // We've collected all the constant (and thus potentially function or
-  // function containing) operands to all of the instructions in the function.
-  // Process them (recursively) collecting every function found.
-  visitReferences(Worklist, Visited, [&](Function &F) {
-    addEdge(Edges->Edges, Edges->EdgeIndexMap, G->get(F),
-            LazyCallGraph::Edge::Ref);
-  });
-
-  // Add implicit reference edges to any defined libcall functions (if we
-  // haven't found an explicit edge).
-  for (auto *F : G->LibFunctions)
-    if (!Visited.count(F))
-      addEdge(Edges->Edges, Edges->EdgeIndexMap, G->get(*F),
-              LazyCallGraph::Edge::Ref);
-
-  return *Edges;
-}
-
-void LazyCallGraph::Node::replaceFunction(Function &NewF) {
-  assert(F != &NewF && "Must not replace a function with itself!");
-  F = &NewF;
-}
-
-#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
-LLVM_DUMP_METHOD void LazyCallGraph::Node::dump() const {
-  dbgs() << *this << '\n';
-}
-#endif
-
-static bool isKnownLibFunction(Function &F, TargetLibraryInfo &TLI) {
-  LibFunc LF;
-
-  // Either this is a normal library function or a "vectorizable"
-  // function.  Not using the VFDatabase here because this query
-  // is related only to libraries handled via the TLI.
-  return TLI.getLibFunc(F, LF) ||
-         TLI.isKnownVectorFunctionInLibrary(F.getName());
-}
-
-LazyCallGraph::LazyCallGraph(
-    Module &M, function_ref<TargetLibraryInfo &(Function &)> GetTLI) {
-  LLVM_DEBUG(dbgs() << "Building CG for module: " << M.getModuleIdentifier()
-                    << "\n");
-  for (Function &F : M) {
-    if (F.isDeclaration())
-      continue;
-    // If this function is a known lib function to LLVM then we want to
-    // synthesize reference edges to it to model the fact that LLVM can turn
-    // arbitrary code into a library function call.
-    if (isKnownLibFunction(F, GetTLI(F)))
-      LibFunctions.insert(&F);
-
-    if (F.hasLocalLinkage())
-      continue;
-
-    // External linkage defined functions have edges to them from other
-    // modules.
-    LLVM_DEBUG(dbgs() << "  Adding '" << F.getName()
-                      << "' to entry set of the graph.\n");
-    addEdge(EntryEdges.Edges, EntryEdges.EdgeIndexMap, get(F), Edge::Ref);
-  }
-
-  // Externally visible aliases of internal functions are also viable entry
-  // edges to the module.
-  for (auto &A : M.aliases()) {
-    if (A.hasLocalLinkage())
-      continue;
-    if (Function* F = dyn_cast<Function>(A.getAliasee())) {
-      LLVM_DEBUG(dbgs() << "  Adding '" << F->getName()
-                        << "' with alias '" << A.getName()
-                        << "' to entry set of the graph.\n");
-      addEdge(EntryEdges.Edges, EntryEdges.EdgeIndexMap, get(*F), Edge::Ref);
-    }
-  }
-
-  // Now add entry nodes for functions reachable via initializers to globals.
-  SmallVector<Constant *, 16> Worklist;
-  SmallPtrSet<Constant *, 16> Visited;
-  for (GlobalVariable &GV : M.globals())
-    if (GV.hasInitializer())
-      if (Visited.insert(GV.getInitializer()).second)
-        Worklist.push_back(GV.getInitializer());
-
-  LLVM_DEBUG(
-      dbgs() << "  Adding functions referenced by global initializers to the "
-                "entry set.\n");
-  visitReferences(Worklist, Visited, [&](Function &F) {
-    addEdge(EntryEdges.Edges, EntryEdges.EdgeIndexMap, get(F),
-            LazyCallGraph::Edge::Ref);
-  });
-}
-
-LazyCallGraph::LazyCallGraph(LazyCallGraph &&G)
-    : BPA(std::move(G.BPA)), NodeMap(std::move(G.NodeMap)),
-      EntryEdges(std::move(G.EntryEdges)), SCCBPA(std::move(G.SCCBPA)),
-      SCCMap(std::move(G.SCCMap)),
-      LibFunctions(std::move(G.LibFunctions)) {
-  updateGraphPtrs();
-}
-
-bool LazyCallGraph::invalidate(Module &, const PreservedAnalyses &PA,
-                               ModuleAnalysisManager::Invalidator &) {
-  // Check whether the analysis, all analyses on functions, or the function's
-  // CFG have been preserved.
-  auto PAC = PA.getChecker<llvm::LazyCallGraphAnalysis>();
-  return !(PAC.preserved() || PAC.preservedSet<AllAnalysesOn<Module>>());
-}
-
-LazyCallGraph &LazyCallGraph::operator=(LazyCallGraph &&G) {
-  BPA = std::move(G.BPA);
-  NodeMap = std::move(G.NodeMap);
-  EntryEdges = std::move(G.EntryEdges);
-  SCCBPA = std::move(G.SCCBPA);
-  SCCMap = std::move(G.SCCMap);
-  LibFunctions = std::move(G.LibFunctions);
-  updateGraphPtrs();
-  return *this;
-}
-
-#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
-LLVM_DUMP_METHOD void LazyCallGraph::SCC::dump() const {
-  dbgs() << *this << '\n';
-}
-#endif
-
-#if !defined(NDEBUG) || defined(EXPENSIVE_CHECKS)
-void LazyCallGraph::SCC::verify() {
-  assert(OuterRefSCC && "Can't have a null RefSCC!");
-  assert(!Nodes.empty() && "Can't have an empty SCC!");
-
-  for (Node *N : Nodes) {
-    assert(N && "Can't have a null node!");
-    assert(OuterRefSCC->G->lookupSCC(*N) == this &&
-           "Node does not map to this SCC!");
-    assert(N->DFSNumber == -1 &&
-           "Must set DFS numbers to -1 when adding a node to an SCC!");
-    assert(N->LowLink == -1 &&
-           "Must set low link to -1 when adding a node to an SCC!");
-    for (Edge &E : **N)
-      assert(E.getNode().isPopulated() && "Can't have an unpopulated node!");
-
-#ifdef EXPENSIVE_CHECKS
-    // Verify that all nodes in this SCC can reach all other nodes.
-    SmallVector<Node *, 4> Worklist;
-    SmallPtrSet<Node *, 4> Visited;
-    Worklist.push_back(N);
-    while (!Worklist.empty()) {
-      Node *VisitingNode = Worklist.pop_back_val();
-      if (!Visited.insert(VisitingNode).second)
-        continue;
-      for (Edge &E : (*VisitingNode)->calls())
-        Worklist.push_back(&E.getNode());
-    }
-    for (Node *NodeToVisit : Nodes) {
-      assert(Visited.contains(NodeToVisit) &&
-             "Cannot reach all nodes within SCC");
-    }
-#endif
-  }
-}
-#endif
-
-bool LazyCallGraph::SCC::isParentOf(const SCC &C) const {
-  if (this == &C)
-    return false;
-
-  for (Node &N : *this)
-    for (Edge &E : N->calls())
-      if (OuterRefSCC->G->lookupSCC(E.getNode()) == &C)
-        return true;
-
-  // No edges found.
-  return false;
-}
-
-bool LazyCallGraph::SCC::isAncestorOf(const SCC &TargetC) const {
-  if (this == &TargetC)
-    return false;
-
-  LazyCallGraph &G = *OuterRefSCC->G;
-
-  // Start with this SCC.
-  SmallPtrSet<const SCC *, 16> Visited = {this};
-  SmallVector<const SCC *, 16> Worklist = {this};
-
-  // Walk down the graph until we run out of edges or find a path to TargetC.
-  do {
-    const SCC &C = *Worklist.pop_back_val();
-    for (Node &N : C)
-      for (Edge &E : N->calls()) {
-        SCC *CalleeC = G.lookupSCC(E.getNode());
-        if (!CalleeC)
-          continue;
-
-        // If the callee's SCC is the TargetC, we're done.
-        if (CalleeC == &TargetC)
-          return true;
-
-        // If this is the first time we've reached this SCC, put it on the
-        // worklist to recurse through.
-        if (Visited.insert(CalleeC).second)
-          Worklist.push_back(CalleeC);
-      }
-  } while (!Worklist.empty());
-
-  // No paths found.
-  return false;
-}
-
-LazyCallGraph::RefSCC::RefSCC(LazyCallGraph &G) : G(&G) {}
-
-#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
-LLVM_DUMP_METHOD void LazyCallGraph::RefSCC::dump() const {
-  dbgs() << *this << '\n';
-}
-#endif
-
-#if !defined(NDEBUG) || defined(EXPENSIVE_CHECKS)
-void LazyCallGraph::RefSCC::verify() {
-  assert(G && "Can't have a null graph!");
-  assert(!SCCs.empty() && "Can't have an empty SCC!");
-
-  // Verify basic properties of the SCCs.
-  SmallPtrSet<SCC *, 4> SCCSet;
-  for (SCC *C : SCCs) {
-    assert(C && "Can't have a null SCC!");
-    C->verify();
-    assert(&C->getOuterRefSCC() == this &&
-           "SCC doesn't think it is inside this RefSCC!");
-    bool Inserted = SCCSet.insert(C).second;
-    assert(Inserted && "Found a duplicate SCC!");
-    auto IndexIt = SCCIndices.find(C);
-    assert(IndexIt != SCCIndices.end() &&
-           "Found an SCC that doesn't have an index!");
-  }
-
-  // Check that our indices map correctly.
-  for (auto &SCCIndexPair : SCCIndices) {
-    SCC *C = SCCIndexPair.first;
-    int i = SCCIndexPair.second;
-    assert(C && "Can't have a null SCC in the indices!");
-    assert(SCCSet.count(C) && "Found an index for an SCC not in the RefSCC!");
-    assert(SCCs[i] == C && "Index doesn't point to SCC!");
-  }
-
-  // Check that the SCCs are in fact in post-order.
-  for (int i = 0, Size = SCCs.size(); i < Size; ++i) {
-    SCC &SourceSCC = *SCCs[i];
-    for (Node &N : SourceSCC)
-      for (Edge &E : *N) {
-        if (!E.isCall())
-          continue;
-        SCC &TargetSCC = *G->lookupSCC(E.getNode());
-        if (&TargetSCC.getOuterRefSCC() == this) {
-          assert(SCCIndices.find(&TargetSCC)->second <= i &&
-                 "Edge between SCCs violates post-order relationship.");
-          continue;
-        }
-      }
-  }
-
-#ifdef EXPENSIVE_CHECKS
-  // Verify that all nodes in this RefSCC can reach all other nodes.
-  SmallVector<Node *> Nodes;
-  for (SCC *C : SCCs) {
-    for (Node &N : *C)
-      Nodes.push_back(&N);
-  }
-  for (Node *N : Nodes) {
-    SmallVector<Node *, 4> Worklist;
-    SmallPtrSet<Node *, 4> Visited;
-    Worklist.push_back(N);
-    while (!Worklist.empty()) {
-      Node *VisitingNode = Worklist.pop_back_val();
-      if (!Visited.insert(VisitingNode).second)
-        continue;
-      for (Edge &E : **VisitingNode)
-        Worklist.push_back(&E.getNode());
-    }
-    for (Node *NodeToVisit : Nodes) {
-      assert(Visited.contains(NodeToVisit) &&
-             "Cannot reach all nodes within RefSCC");
-    }
-  }
-#endif
-}
-#endif
-
-bool LazyCallGraph::RefSCC::isParentOf(const RefSCC &RC) const {
-  if (&RC == this)
-    return false;
-
-  // Search all edges to see if this is a parent.
-  for (SCC &C : *this)
-    for (Node &N : C)
-      for (Edge &E : *N)
-        if (G->lookupRefSCC(E.getNode()) == &RC)
-          return true;
-
-  return false;
-}
-
-bool LazyCallGraph::RefSCC::isAncestorOf(const RefSCC &RC) const {
-  if (&RC == this)
-    return false;
-
-  // For each descendant of this RefSCC, see if one of its children is the
-  // argument. If not, add that descendant to the worklist and continue
-  // searching.
-  SmallVector<const RefSCC *, 4> Worklist;
-  SmallPtrSet<const RefSCC *, 4> Visited;
-  Worklist.push_back(this);
-  Visited.insert(this);
-  do {
-    const RefSCC &DescendantRC = *Worklist.pop_back_val();
-    for (SCC &C : DescendantRC)
-      for (Node &N : C)
-        for (Edge &E : *N) {
-          auto *ChildRC = G->lookupRefSCC(E.getNode());
-          if (ChildRC == &RC)
-            return true;
-          if (!ChildRC || !Visited.insert(ChildRC).second)
-            continue;
-          Worklist.push_back(ChildRC);
-        }
-  } while (!Worklist.empty());
-
-  return false;
-}
-
-/// Generic helper that updates a postorder sequence of SCCs for a potentially
-/// cycle-introducing edge insertion.
-///
-/// A postorder sequence of SCCs of a directed graph has one fundamental
-/// property: all deges in the DAG of SCCs point "up" the sequence. That is,
-/// all edges in the SCC DAG point to prior SCCs in the sequence.
-///
-/// This routine both updates a postorder sequence and uses that sequence to
-/// compute the set of SCCs connected into a cycle. It should only be called to
-/// insert a "downward" edge which will require changing the sequence to
-/// restore it to a postorder.
-///
-/// When inserting an edge from an earlier SCC to a later SCC in some postorder
-/// sequence, all of the SCCs which may be impacted are in the closed range of
-/// those two within the postorder sequence. The algorithm used here to restore
-/// the state is as follows:
-///
-/// 1) Starting from the source SCC, construct a set of SCCs which reach the
-///    source SCC consisting of just the source SCC. Then scan toward the
-///    target SCC in postorder and for each SCC, if it has an edge to an SCC
-///    in the set, add it to the set. Otherwise, the source SCC is not
-///    a successor, move it in the postorder sequence to immediately before
-///    the source SCC, shifting the source SCC and all SCCs in the set one
-///    position toward the target SCC. Stop scanning after processing the
-///    target SCC.
-/// 2) If the source SCC is now past the target SCC in the postorder sequence,
-///    and thus the new edge will flow toward the start, we are done.
-/// 3) Otherwise, starting from the target SCC, walk all edges which reach an
-///    SCC between the source and the target, and add them to the set of
-///    connected SCCs, then recurse through them. Once a complete set of the
-///    SCCs the target connects to is known, hoist the remaining SCCs between
-///    the source and the target to be above the target. Note that there is no
-///    need to process the source SCC, it is already known to connect.
-/// 4) At this point, all of the SCCs in the closed range between the source
-///    SCC and the target SCC in the postorder sequence are connected,
-///    including the target SCC and the source SCC. Inserting the edge from
-///    the source SCC to the target SCC will form a cycle out of precisely
-///    these SCCs. Thus we can merge all of the SCCs in this closed range into
-///    a single SCC.
-///
-/// This process has various important properties:
-/// - Only mutates the SCCs when adding the edge actually changes the SCC
-///   structure.
-/// - Never mutates SCCs which are unaffected by the change.
-/// - Updates the postorder sequence to correctly satisfy the postorder
-///   constraint after the edge is inserted.
-/// - Only reorders SCCs in the closed postorder sequence from the source to
-///   the target, so easy to bound how much has changed even in the ordering.
-/// - Big-O is the number of edges in the closed postorder range of SCCs from
-///   source to target.
-///
-/// This helper routine, in addition to updating the postorder sequence itself
-/// will also update a map from SCCs to indices within that sequence.
-///
-/// The sequence and the map must operate on pointers to the SCC type.
-///
-/// Two callbacks must be provided. The first computes the subset of SCCs in
-/// the postorder closed range from the source to the target which connect to
-/// the source SCC via some (transitive) set of edges. The second computes the
-/// subset of the same range which the target SCC connects to via some
-/// (transitive) set of edges. Both callbacks should populate the set argument
-/// provided.
-template <typename SCCT, typename PostorderSequenceT, typename SCCIndexMapT,
-          typename ComputeSourceConnectedSetCallableT,
-          typename ComputeTargetConnectedSetCallableT>
-static iterator_range<typename PostorderSequenceT::iterator>
-updatePostorderSequenceForEdgeInsertion(
-    SCCT &SourceSCC, SCCT &TargetSCC, PostorderSequenceT &SCCs,
-    SCCIndexMapT &SCCIndices,
-    ComputeSourceConnectedSetCallableT ComputeSourceConnectedSet,
-    ComputeTargetConnectedSetCallableT ComputeTargetConnectedSet) {
-  int SourceIdx = SCCIndices[&SourceSCC];
-  int TargetIdx = SCCIndices[&TargetSCC];
-  assert(SourceIdx < TargetIdx && "Cannot have equal indices here!");
-
-  SmallPtrSet<SCCT *, 4> ConnectedSet;
-
-  // Compute the SCCs which (transitively) reach the source.
-  ComputeSourceConnectedSet(ConnectedSet);
-
-  // Partition the SCCs in this part of the port-order sequence so only SCCs
-  // connecting to the source remain between it and the target. This is
-  // a benign partition as it preserves postorder.
-  auto SourceI = std::stable_partition(
-      SCCs.begin() + SourceIdx, SCCs.begin() + TargetIdx + 1,
-      [&ConnectedSet](SCCT *C) { return !ConnectedSet.count(C); });
-  for (int i = SourceIdx, e = TargetIdx + 1; i < e; ++i)
-    SCCIndices.find(SCCs[i])->second = i;
-
-  // If the target doesn't connect to the source, then we've corrected the
-  // post-order and there are no cycles formed.
-  if (!ConnectedSet.count(&TargetSCC)) {
-    assert(SourceI > (SCCs.begin() + SourceIdx) &&
-           "Must have moved the source to fix the post-order.");
-    assert(*std::prev(SourceI) == &TargetSCC &&
-           "Last SCC to move should have bene the target.");
-
-    // Return an empty range at the target SCC indicating there is nothing to
-    // merge.
-    return make_range(std::prev(SourceI), std::prev(SourceI));
-  }
-
-  assert(SCCs[TargetIdx] == &TargetSCC &&
-         "Should not have moved target if connected!");
-  SourceIdx = SourceI - SCCs.begin();
-  assert(SCCs[SourceIdx] == &SourceSCC &&
-         "Bad updated index computation for the source SCC!");
-
-
-  // See whether there are any remaining intervening SCCs between the source
-  // and target. If so we need to make sure they all are reachable form the
-  // target.
-  if (SourceIdx + 1 < TargetIdx) {
-    ConnectedSet.clear();
-    ComputeTargetConnectedSet(ConnectedSet);
-
-    // Partition SCCs so that only SCCs reached from the target remain between
-    // the source and the target. This preserves postorder.
-    auto TargetI = std::stable_partition(
-        SCCs.begin() + SourceIdx + 1, SCCs.begin() + TargetIdx + 1,
-        [&ConnectedSet](SCCT *C) { return ConnectedSet.count(C); });
-    for (int i = SourceIdx + 1, e = TargetIdx + 1; i < e; ++i)
-      SCCIndices.find(SCCs[i])->second = i;
-    TargetIdx = std::prev(TargetI) - SCCs.begin();
-    assert(SCCs[TargetIdx] == &TargetSCC &&
-           "Should always end with the target!");
-  }
-
-  // At this point, we know that connecting source to target forms a cycle
-  // because target connects back to source, and we know that all of the SCCs
-  // between the source and target in the postorder sequence participate in that
-  // cycle.
-  return make_range(SCCs.begin() + SourceIdx, SCCs.begin() + TargetIdx);
-}
-
-bool
-LazyCallGraph::RefSCC::switchInternalEdgeToCall(
-    Node &SourceN, Node &TargetN,
-    function_ref<void(ArrayRef<SCC *> MergeSCCs)> MergeCB) {
-  assert(!(*SourceN)[TargetN].isCall() && "Must start with a ref edge!");
-  SmallVector<SCC *, 1> DeletedSCCs;
-
-#ifdef EXPENSIVE_CHECKS
-  verify();
-  auto VerifyOnExit = make_scope_exit([&]() { verify(); });
-#endif
-
-  SCC &SourceSCC = *G->lookupSCC(SourceN);
-  SCC &TargetSCC = *G->lookupSCC(TargetN);
-
-  // If the two nodes are already part of the same SCC, we're also done as
-  // we've just added more connectivity.
-  if (&SourceSCC == &TargetSCC) {
-    SourceN->setEdgeKind(TargetN, Edge::Call);
-    return false; // No new cycle.
-  }
-
-  // At this point we leverage the postorder list of SCCs to detect when the
-  // insertion of an edge changes the SCC structure in any way.
-  //
-  // First and foremost, we can eliminate the need for any changes when the
-  // edge is toward the beginning of the postorder sequence because all edges
-  // flow in that direction already. Thus adding a new one cannot form a cycle.
-  int SourceIdx = SCCIndices[&SourceSCC];
-  int TargetIdx = SCCIndices[&TargetSCC];
-  if (TargetIdx < SourceIdx) {
-    SourceN->setEdgeKind(TargetN, Edge::Call);
-    return false; // No new cycle.
-  }
-
-  // Compute the SCCs which (transitively) reach the source.
-  auto ComputeSourceConnectedSet = [&](SmallPtrSetImpl<SCC *> &ConnectedSet) {
-#ifdef EXPENSIVE_CHECKS
-    // Check that the RefSCC is still valid before computing this as the
-    // results will be nonsensical of we've broken its invariants.
-    verify();
-#endif
-    ConnectedSet.insert(&SourceSCC);
-    auto IsConnected = [&](SCC &C) {
-      for (Node &N : C)
-        for (Edge &E : N->calls())
-          if (ConnectedSet.count(G->lookupSCC(E.getNode())))
-            return true;
-
-      return false;
-    };
-
-    for (SCC *C :
-         make_range(SCCs.begin() + SourceIdx + 1, SCCs.begin() + TargetIdx + 1))
-      if (IsConnected(*C))
-        ConnectedSet.insert(C);
-  };
-
-  // Use a normal worklist to find which SCCs the target connects to. We still
-  // bound the search based on the range in the postorder list we care about,
-  // but because this is forward connectivity we just "recurse" through the
-  // edges.
-  auto ComputeTargetConnectedSet = [&](SmallPtrSetImpl<SCC *> &ConnectedSet) {
-#ifdef EXPENSIVE_CHECKS
-    // Check that the RefSCC is still valid before computing this as the
-    // results will be nonsensical of we've broken its invariants.
-    verify();
-#endif
-    ConnectedSet.insert(&TargetSCC);
-    SmallVector<SCC *, 4> Worklist;
-    Worklist.push_back(&TargetSCC);
-    do {
-      SCC &C = *Worklist.pop_back_val();
-      for (Node &N : C)
-        for (Edge &E : *N) {
-          if (!E.isCall())
-            continue;
-          SCC &EdgeC = *G->lookupSCC(E.getNode());
-          if (&EdgeC.getOuterRefSCC() != this)
-            // Not in this RefSCC...
-            continue;
-          if (SCCIndices.find(&EdgeC)->second <= SourceIdx)
-            // Not in the postorder sequence between source and target.
-            continue;
-
-          if (ConnectedSet.insert(&EdgeC).second)
-            Worklist.push_back(&EdgeC);
-        }
-    } while (!Worklist.empty());
-  };
-
-  // Use a generic helper to update the postorder sequence of SCCs and return
-  // a range of any SCCs connected into a cycle by inserting this edge. This
-  // routine will also take care of updating the indices into the postorder
-  // sequence.
-  auto MergeRange = updatePostorderSequenceForEdgeInsertion(
-      SourceSCC, TargetSCC, SCCs, SCCIndices, ComputeSourceConnectedSet,
-      ComputeTargetConnectedSet);
-
-  // Run the user's callback on the merged SCCs before we actually merge them.
-  if (MergeCB)
-    MergeCB(makeArrayRef(MergeRange.begin(), MergeRange.end()));
-
-  // If the merge range is empty, then adding the edge didn't actually form any
-  // new cycles. We're done.
-  if (MergeRange.empty()) {
-    // Now that the SCC structure is finalized, flip the kind to call.
-    SourceN->setEdgeKind(TargetN, Edge::Call);
-    return false; // No new cycle.
-  }
-
-#ifdef EXPENSIVE_CHECKS
-  // Before merging, check that the RefSCC remains valid after all the
-  // postorder updates.
-  verify();
-#endif
-
-  // Otherwise we need to merge all of the SCCs in the cycle into a single
-  // result SCC.
-  //
-  // NB: We merge into the target because all of these functions were already
-  // reachable from the target, meaning any SCC-wide properties deduced about it
-  // other than the set of functions within it will not have changed.
-  for (SCC *C : MergeRange) {
-    assert(C != &TargetSCC &&
-           "We merge *into* the target and shouldn't process it here!");
-    SCCIndices.erase(C);
-    TargetSCC.Nodes.append(C->Nodes.begin(), C->Nodes.end());
-    for (Node *N : C->Nodes)
-      G->SCCMap[N] = &TargetSCC;
-    C->clear();
-    DeletedSCCs.push_back(C);
-  }
-
-  // Erase the merged SCCs from the list and update the indices of the
-  // remaining SCCs.
-  int IndexOffset = MergeRange.end() - MergeRange.begin();
-  auto EraseEnd = SCCs.erase(MergeRange.begin(), MergeRange.end());
-  for (SCC *C : make_range(EraseEnd, SCCs.end()))
-    SCCIndices[C] -= IndexOffset;
-
-  // Now that the SCC structure is finalized, flip the kind to call.
-  SourceN->setEdgeKind(TargetN, Edge::Call);
-
-  // And we're done, but we did form a new cycle.
-  return true;
-}
-
-void LazyCallGraph::RefSCC::switchTrivialInternalEdgeToRef(Node &SourceN,
-                                                           Node &TargetN) {
-  assert((*SourceN)[TargetN].isCall() && "Must start with a call edge!");
-
-#ifdef EXPENSIVE_CHECKS
-  verify();
-  auto VerifyOnExit = make_scope_exit([&]() { verify(); });
-#endif
-
-  assert(G->lookupRefSCC(SourceN) == this &&
-         "Source must be in this RefSCC.");
-  assert(G->lookupRefSCC(TargetN) == this &&
-         "Target must be in this RefSCC.");
-  assert(G->lookupSCC(SourceN) != G->lookupSCC(TargetN) &&
-         "Source and Target must be in separate SCCs for this to be trivial!");
-
-  // Set the edge kind.
-  SourceN->setEdgeKind(TargetN, Edge::Ref);
-}
-
-iterator_range<LazyCallGraph::RefSCC::iterator>
-LazyCallGraph::RefSCC::switchInternalEdgeToRef(Node &SourceN, Node &TargetN) {
-  assert((*SourceN)[TargetN].isCall() && "Must start with a call edge!");
-
-#ifdef EXPENSIVE_CHECKS
-  verify();
-  auto VerifyOnExit = make_scope_exit([&]() { verify(); });
-#endif
-
-  assert(G->lookupRefSCC(SourceN) == this &&
-         "Source must be in this RefSCC.");
-  assert(G->lookupRefSCC(TargetN) == this &&
-         "Target must be in this RefSCC.");
-
-  SCC &TargetSCC = *G->lookupSCC(TargetN);
-  assert(G->lookupSCC(SourceN) == &TargetSCC && "Source and Target must be in "
-                                                "the same SCC to require the "
-                                                "full CG update.");
-
-  // Set the edge kind.
-  SourceN->setEdgeKind(TargetN, Edge::Ref);
-
-  // Otherwise we are removing a call edge from a single SCC. This may break
-  // the cycle. In order to compute the new set of SCCs, we need to do a small
-  // DFS over the nodes within the SCC to form any sub-cycles that remain as
-  // distinct SCCs and compute a postorder over the resulting SCCs.
-  //
-  // However, we specially handle the target node. The target node is known to
-  // reach all other nodes in the original SCC by definition. This means that
-  // we want the old SCC to be replaced with an SCC containing that node as it
-  // will be the root of whatever SCC DAG results from the DFS. Assumptions
-  // about an SCC such as the set of functions called will continue to hold,
-  // etc.
-
-  SCC &OldSCC = TargetSCC;
-  SmallVector<std::pair<Node *, EdgeSequence::call_iterator>, 16> DFSStack;
-  SmallVector<Node *, 16> PendingSCCStack;
-  SmallVector<SCC *, 4> NewSCCs;
-
-  // Prepare the nodes for a fresh DFS.
-  SmallVector<Node *, 16> Worklist;
-  Worklist.swap(OldSCC.Nodes);
-  for (Node *N : Worklist) {
-    N->DFSNumber = N->LowLink = 0;
-    G->SCCMap.erase(N);
-  }
-
-  // Force the target node to be in the old SCC. This also enables us to take
-  // a very significant short-cut in the standard Tarjan walk to re-form SCCs
-  // below: whenever we build an edge that reaches the target node, we know
-  // that the target node eventually connects back to all other nodes in our
-  // walk. As a consequence, we can detect and handle participants in that
-  // cycle without walking all the edges that form this connection, and instead
-  // by relying on the fundamental guarantee coming into this operation (all
-  // nodes are reachable from the target due to previously forming an SCC).
-  TargetN.DFSNumber = TargetN.LowLink = -1;
-  OldSCC.Nodes.push_back(&TargetN);
-  G->SCCMap[&TargetN] = &OldSCC;
-
-  // Scan down the stack and DFS across the call edges.
-  for (Node *RootN : Worklist) {
-    assert(DFSStack.empty() &&
-           "Cannot begin a new root with a non-empty DFS stack!");
-    assert(PendingSCCStack.empty() &&
-           "Cannot begin a new root with pending nodes for an SCC!");
-
-    // Skip any nodes we've already reached in the DFS.
-    if (RootN->DFSNumber != 0) {
-      assert(RootN->DFSNumber == -1 &&
-             "Shouldn't have any mid-DFS root nodes!");
-      continue;
-    }
-
-    RootN->DFSNumber = RootN->LowLink = 1;
-    int NextDFSNumber = 2;
-
-    DFSStack.push_back({RootN, (*RootN)->call_begin()});
-    do {
-      Node *N;
-      EdgeSequence::call_iterator I;
-      std::tie(N, I) = DFSStack.pop_back_val();
-      auto E = (*N)->call_end();
-      while (I != E) {
-        Node &ChildN = I->getNode();
-        if (ChildN.DFSNumber == 0) {
-          // We haven't yet visited this child, so descend, pushing the current
-          // node onto the stack.
-          DFSStack.push_back({N, I});
-
-          assert(!G->SCCMap.count(&ChildN) &&
-                 "Found a node with 0 DFS number but already in an SCC!");
-          ChildN.DFSNumber = ChildN.LowLink = NextDFSNumber++;
-          N = &ChildN;
-          I = (*N)->call_begin();
-          E = (*N)->call_end();
-          continue;
-        }
-
-        // Check for the child already being part of some component.
-        if (ChildN.DFSNumber == -1) {
-          if (G->lookupSCC(ChildN) == &OldSCC) {
-            // If the child is part of the old SCC, we know that it can reach
-            // every other node, so we have formed a cycle. Pull the entire DFS
-            // and pending stacks into it. See the comment above about setting
-            // up the old SCC for why we do this.
-            int OldSize = OldSCC.size();
-            OldSCC.Nodes.push_back(N);
-            OldSCC.Nodes.append(PendingSCCStack.begin(), PendingSCCStack.end());
-            PendingSCCStack.clear();
-            while (!DFSStack.empty())
-              OldSCC.Nodes.push_back(DFSStack.pop_back_val().first);
-            for (Node &N : drop_begin(OldSCC, OldSize)) {
-              N.DFSNumber = N.LowLink = -1;
-              G->SCCMap[&N] = &OldSCC;
-            }
-            N = nullptr;
-            break;
-          }
-
-          // If the child has already been added to some child component, it
-          // couldn't impact the low-link of this parent because it isn't
-          // connected, and thus its low-link isn't relevant so skip it.
-          ++I;
-          continue;
-        }
-
-        // Track the lowest linked child as the lowest link for this node.
-        assert(ChildN.LowLink > 0 && "Must have a positive low-link number!");
-        if (ChildN.LowLink < N->LowLink)
-          N->LowLink = ChildN.LowLink;
-
-        // Move to the next edge.
-        ++I;
-      }
-      if (!N)
-        // Cleared the DFS early, start another round.
-        break;
-
-      // We've finished processing N and its descendants, put it on our pending
-      // SCC stack to eventually get merged into an SCC of nodes.
-      PendingSCCStack.push_back(N);
-
-      // If this node is linked to some lower entry, continue walking up the
-      // stack.
-      if (N->LowLink != N->DFSNumber)
-        continue;
-
-      // Otherwise, we've completed an SCC. Append it to our post order list of
-      // SCCs.
-      int RootDFSNumber = N->DFSNumber;
-      // Find the range of the node stack by walking down until we pass the
-      // root DFS number.
-      auto SCCNodes = make_range(
-          PendingSCCStack.rbegin(),
-          find_if(reverse(PendingSCCStack), [RootDFSNumber](const Node *N) {
-            return N->DFSNumber < RootDFSNumber;
-          }));
-
-      // Form a new SCC out of these nodes and then clear them off our pending
-      // stack.
-      NewSCCs.push_back(G->createSCC(*this, SCCNodes));
-      for (Node &N : *NewSCCs.back()) {
-        N.DFSNumber = N.LowLink = -1;
-        G->SCCMap[&N] = NewSCCs.back();
-      }
-      PendingSCCStack.erase(SCCNodes.end().base(), PendingSCCStack.end());
-    } while (!DFSStack.empty());
-  }
-
-  // Insert the remaining SCCs before the old one. The old SCC can reach all
-  // other SCCs we form because it contains the target node of the removed edge
-  // of the old SCC. This means that we will have edges into all of the new
-  // SCCs, which means the old one must come last for postorder.
-  int OldIdx = SCCIndices[&OldSCC];
-  SCCs.insert(SCCs.begin() + OldIdx, NewSCCs.begin(), NewSCCs.end());
-
-  // Update the mapping from SCC* to index to use the new SCC*s, and remove the
-  // old SCC from the mapping.
-  for (int Idx = OldIdx, Size = SCCs.size(); Idx < Size; ++Idx)
-    SCCIndices[SCCs[Idx]] = Idx;
-
-  return make_range(SCCs.begin() + OldIdx,
-                    SCCs.begin() + OldIdx + NewSCCs.size());
-}
-
-void LazyCallGraph::RefSCC::switchOutgoingEdgeToCall(Node &SourceN,
-                                                     Node &TargetN) {
-  assert(!(*SourceN)[TargetN].isCall() && "Must start with a ref edge!");
-
-  assert(G->lookupRefSCC(SourceN) == this && "Source must be in this RefSCC.");
-  assert(G->lookupRefSCC(TargetN) != this &&
-         "Target must not be in this RefSCC.");
-#ifdef EXPENSIVE_CHECKS
-  assert(G->lookupRefSCC(TargetN)->isDescendantOf(*this) &&
-         "Target must be a descendant of the Source.");
-#endif
-
-  // Edges between RefSCCs are the same regardless of call or ref, so we can
-  // just flip the edge here.
-  SourceN->setEdgeKind(TargetN, Edge::Call);
-
-#ifdef EXPENSIVE_CHECKS
-  verify();
-#endif
-}
-
-void LazyCallGraph::RefSCC::switchOutgoingEdgeToRef(Node &SourceN,
-                                                    Node &TargetN) {
-  assert((*SourceN)[TargetN].isCall() && "Must start with a call edge!");
-
-  assert(G->lookupRefSCC(SourceN) == this && "Source must be in this RefSCC.");
-  assert(G->lookupRefSCC(TargetN) != this &&
-         "Target must not be in this RefSCC.");
-#ifdef EXPENSIVE_CHECKS
-  assert(G->lookupRefSCC(TargetN)->isDescendantOf(*this) &&
-         "Target must be a descendant of the Source.");
-#endif
-
-  // Edges between RefSCCs are the same regardless of call or ref, so we can
-  // just flip the edge here.
-  SourceN->setEdgeKind(TargetN, Edge::Ref);
-
-#ifdef EXPENSIVE_CHECKS
-  verify();
-#endif
-}
-
-void LazyCallGraph::RefSCC::insertInternalRefEdge(Node &SourceN,
-                                                  Node &TargetN) {
-  assert(G->lookupRefSCC(SourceN) == this && "Source must be in this RefSCC.");
-  assert(G->lookupRefSCC(TargetN) == this && "Target must be in this RefSCC.");
-
-  SourceN->insertEdgeInternal(TargetN, Edge::Ref);
-
-#ifdef EXPENSIVE_CHECKS
-  verify();
-#endif
-}
-
-void LazyCallGraph::RefSCC::insertOutgoingEdge(Node &SourceN, Node &TargetN,
-                                               Edge::Kind EK) {
-  // First insert it into the caller.
-  SourceN->insertEdgeInternal(TargetN, EK);
-
-  assert(G->lookupRefSCC(SourceN) == this && "Source must be in this RefSCC.");
-
-  assert(G->lookupRefSCC(TargetN) != this &&
-         "Target must not be in this RefSCC.");
-#ifdef EXPENSIVE_CHECKS
-  assert(G->lookupRefSCC(TargetN)->isDescendantOf(*this) &&
-         "Target must be a descendant of the Source.");
-#endif
-
-#ifdef EXPENSIVE_CHECKS
-  verify();
-#endif
-}
-
-SmallVector<LazyCallGraph::RefSCC *, 1>
-LazyCallGraph::RefSCC::insertIncomingRefEdge(Node &SourceN, Node &TargetN) {
-  assert(G->lookupRefSCC(TargetN) == this && "Target must be in this RefSCC.");
-  RefSCC &SourceC = *G->lookupRefSCC(SourceN);
-  assert(&SourceC != this && "Source must not be in this RefSCC.");
-#ifdef EXPENSIVE_CHECKS
-  assert(SourceC.isDescendantOf(*this) &&
-         "Source must be a descendant of the Target.");
-#endif
-
-  SmallVector<RefSCC *, 1> DeletedRefSCCs;
-
-#ifdef EXPENSIVE_CHECKS
-  verify();
-  auto VerifyOnExit = make_scope_exit([&]() { verify(); });
-#endif
-
-  int SourceIdx = G->RefSCCIndices[&SourceC];
-  int TargetIdx = G->RefSCCIndices[this];
-  assert(SourceIdx < TargetIdx &&
-         "Postorder list doesn't see edge as incoming!");
-
-  // Compute the RefSCCs which (transitively) reach the source. We do this by
-  // working backwards from the source using the parent set in each RefSCC,
-  // skipping any RefSCCs that don't fall in the postorder range. This has the
-  // advantage of walking the sparser parent edge (in high fan-out graphs) but
-  // more importantly this removes examining all forward edges in all RefSCCs
-  // within the postorder range which aren't in fact connected. Only connected
-  // RefSCCs (and their edges) are visited here.
-  auto ComputeSourceConnectedSet = [&](SmallPtrSetImpl<RefSCC *> &Set) {
-    Set.insert(&SourceC);
-    auto IsConnected = [&](RefSCC &RC) {
-      for (SCC &C : RC)
-        for (Node &N : C)
-          for (Edge &E : *N)
-            if (Set.count(G->lookupRefSCC(E.getNode())))
-              return true;
-
-      return false;
-    };
-
-    for (RefSCC *C : make_range(G->PostOrderRefSCCs.begin() + SourceIdx + 1,
-                                G->PostOrderRefSCCs.begin() + TargetIdx + 1))
-      if (IsConnected(*C))
-        Set.insert(C);
-  };
-
-  // Use a normal worklist to find which SCCs the target connects to. We still
-  // bound the search based on the range in the postorder list we care about,
-  // but because this is forward connectivity we just "recurse" through the
-  // edges.
-  auto ComputeTargetConnectedSet = [&](SmallPtrSetImpl<RefSCC *> &Set) {
-    Set.insert(this);
-    SmallVector<RefSCC *, 4> Worklist;
-    Worklist.push_back(this);
-    do {
-      RefSCC &RC = *Worklist.pop_back_val();
-      for (SCC &C : RC)
-        for (Node &N : C)
-          for (Edge &E : *N) {
-            RefSCC &EdgeRC = *G->lookupRefSCC(E.getNode());
-            if (G->getRefSCCIndex(EdgeRC) <= SourceIdx)
-              // Not in the postorder sequence between source and target.
-              continue;
-
-            if (Set.insert(&EdgeRC).second)
-              Worklist.push_back(&EdgeRC);
-          }
-    } while (!Worklist.empty());
-  };
-
-  // Use a generic helper to update the postorder sequence of RefSCCs and return
-  // a range of any RefSCCs connected into a cycle by inserting this edge. This
-  // routine will also take care of updating the indices into the postorder
-  // sequence.
-  iterator_range<SmallVectorImpl<RefSCC *>::iterator> MergeRange =
-      updatePostorderSequenceForEdgeInsertion(
-          SourceC, *this, G->PostOrderRefSCCs, G->RefSCCIndices,
-          ComputeSourceConnectedSet, ComputeTargetConnectedSet);
-
-  // Build a set so we can do fast tests for whether a RefSCC will end up as
-  // part of the merged RefSCC.
-  SmallPtrSet<RefSCC *, 16> MergeSet(MergeRange.begin(), MergeRange.end());
-
-  // This RefSCC will always be part of that set, so just insert it here.
-  MergeSet.insert(this);
-
-  // Now that we have identified all of the SCCs which need to be merged into
-  // a connected set with the inserted edge, merge all of them into this SCC.
-  SmallVector<SCC *, 16> MergedSCCs;
-  int SCCIndex = 0;
-  for (RefSCC *RC : MergeRange) {
-    assert(RC != this && "We're merging into the target RefSCC, so it "
-                         "shouldn't be in the range.");
-
-    // Walk the inner SCCs to update their up-pointer and walk all the edges to
-    // update any parent sets.
-    // FIXME: We should try to find a way to avoid this (rather expensive) edge
-    // walk by updating the parent sets in some other manner.
-    for (SCC &InnerC : *RC) {
-      InnerC.OuterRefSCC = this;
-      SCCIndices[&InnerC] = SCCIndex++;
-      for (Node &N : InnerC)
-        G->SCCMap[&N] = &InnerC;
-    }
-
-    // Now merge in the SCCs. We can actually move here so try to reuse storage
-    // the first time through.
-    if (MergedSCCs.empty())
-      MergedSCCs = std::move(RC->SCCs);
-    else
-      MergedSCCs.append(RC->SCCs.begin(), RC->SCCs.end());
-    RC->SCCs.clear();
-    DeletedRefSCCs.push_back(RC);
-  }
-
-  // Append our original SCCs to the merged list and move it into place.
-  for (SCC &InnerC : *this)
-    SCCIndices[&InnerC] = SCCIndex++;
-  MergedSCCs.append(SCCs.begin(), SCCs.end());
-  SCCs = std::move(MergedSCCs);
-
-  // Remove the merged away RefSCCs from the post order sequence.
-  for (RefSCC *RC : MergeRange)
-    G->RefSCCIndices.erase(RC);
-  int IndexOffset = MergeRange.end() - MergeRange.begin();
-  auto EraseEnd =
-      G->PostOrderRefSCCs.erase(MergeRange.begin(), MergeRange.end());
-  for (RefSCC *RC : make_range(EraseEnd, G->PostOrderRefSCCs.end()))
-    G->RefSCCIndices[RC] -= IndexOffset;
-
-  // At this point we have a merged RefSCC with a post-order SCCs list, just
-  // connect the nodes to form the new edge.
-  SourceN->insertEdgeInternal(TargetN, Edge::Ref);
-
-  // We return the list of SCCs which were merged so that callers can
-  // invalidate any data they have associated with those SCCs. Note that these
-  // SCCs are no longer in an interesting state (they are totally empty) but
-  // the pointers will remain stable for the life of the graph itself.
-  return DeletedRefSCCs;
-}
-
-void LazyCallGraph::RefSCC::removeOutgoingEdge(Node &SourceN, Node &TargetN) {
-  assert(G->lookupRefSCC(SourceN) == this &&
-         "The source must be a member of this RefSCC.");
-  assert(G->lookupRefSCC(TargetN) != this &&
-         "The target must not be a member of this RefSCC");
-
-#ifdef EXPENSIVE_CHECKS
-  verify();
-  auto VerifyOnExit = make_scope_exit([&]() { verify(); });
-#endif
-
-  // First remove it from the node.
-  bool Removed = SourceN->removeEdgeInternal(TargetN);
-  (void)Removed;
-  assert(Removed && "Target not in the edge set for this caller?");
-}
-
-SmallVector<LazyCallGraph::RefSCC *, 1>
-LazyCallGraph::RefSCC::removeInternalRefEdge(Node &SourceN,
-                                             ArrayRef<Node *> TargetNs) {
-  // We return a list of the resulting *new* RefSCCs in post-order.
-  SmallVector<RefSCC *, 1> Result;
-
-#ifdef EXPENSIVE_CHECKS
-  // Verify the RefSCC is valid to start with and that either we return an empty
-  // list of result RefSCCs and this RefSCC remains valid, or we return new
-  // RefSCCs and this RefSCC is dead.
-  verify();
-  auto VerifyOnExit = make_scope_exit([&]() {
-    // If we didn't replace our RefSCC with new ones, check that this one
-    // remains valid.
-    if (G)
-      verify();
-  });
-#endif
-
-  // First remove the actual edges.
-  for (Node *TargetN : TargetNs) {
-    assert(!(*SourceN)[*TargetN].isCall() &&
-           "Cannot remove a call edge, it must first be made a ref edge");
-
-    bool Removed = SourceN->removeEdgeInternal(*TargetN);
-    (void)Removed;
-    assert(Removed && "Target not in the edge set for this caller?");
-  }
-
-  // Direct self references don't impact the ref graph at all.
-  if (llvm::all_of(TargetNs,
-                   [&](Node *TargetN) { return &SourceN == TargetN; }))
-    return Result;
-
-  // If all targets are in the same SCC as the source, because no call edges
-  // were removed there is no RefSCC structure change.
-  SCC &SourceC = *G->lookupSCC(SourceN);
-  if (llvm::all_of(TargetNs, [&](Node *TargetN) {
-        return G->lookupSCC(*TargetN) == &SourceC;
-      }))
-    return Result;
-
-  // We build somewhat synthetic new RefSCCs by providing a postorder mapping
-  // for each inner SCC. We store these inside the low-link field of the nodes
-  // rather than associated with SCCs because this saves a round-trip through
-  // the node->SCC map and in the common case, SCCs are small. We will verify
-  // that we always give the same number to every node in the SCC such that
-  // these are equivalent.
-  int PostOrderNumber = 0;
-
-  // Reset all the other nodes to prepare for a DFS over them, and add them to
-  // our worklist.
-  SmallVector<Node *, 8> Worklist;
-  for (SCC *C : SCCs) {
-    for (Node &N : *C)
-      N.DFSNumber = N.LowLink = 0;
-
-    Worklist.append(C->Nodes.begin(), C->Nodes.end());
-  }
-
-  // Track the number of nodes in this RefSCC so that we can quickly recognize
-  // an important special case of the edge removal not breaking the cycle of
-  // this RefSCC.
-  const int NumRefSCCNodes = Worklist.size();
-
-  SmallVector<std::pair<Node *, EdgeSequence::iterator>, 4> DFSStack;
-  SmallVector<Node *, 4> PendingRefSCCStack;
-  do {
-    assert(DFSStack.empty() &&
-           "Cannot begin a new root with a non-empty DFS stack!");
-    assert(PendingRefSCCStack.empty() &&
-           "Cannot begin a new root with pending nodes for an SCC!");
-
-    Node *RootN = Worklist.pop_back_val();
-    // Skip any nodes we've already reached in the DFS.
-    if (RootN->DFSNumber != 0) {
-      assert(RootN->DFSNumber == -1 &&
-             "Shouldn't have any mid-DFS root nodes!");
-      continue;
-    }
-
-    RootN->DFSNumber = RootN->LowLink = 1;
-    int NextDFSNumber = 2;
-
-    DFSStack.push_back({RootN, (*RootN)->begin()});
-    do {
-      Node *N;
-      EdgeSequence::iterator I;
-      std::tie(N, I) = DFSStack.pop_back_val();
-      auto E = (*N)->end();
-
-      assert(N->DFSNumber != 0 && "We should always assign a DFS number "
-                                  "before processing a node.");
-
-      while (I != E) {
-        Node &ChildN = I->getNode();
-        if (ChildN.DFSNumber == 0) {
-          // Mark that we should start at this child when next this node is the
-          // top of the stack. We don't start at the next child to ensure this
-          // child's lowlink is reflected.
-          DFSStack.push_back({N, I});
-
-          // Continue, resetting to the child node.
-          ChildN.LowLink = ChildN.DFSNumber = NextDFSNumber++;
-          N = &ChildN;
-          I = ChildN->begin();
-          E = ChildN->end();
-          continue;
-        }
-        if (ChildN.DFSNumber == -1) {
-          // If this child isn't currently in this RefSCC, no need to process
-          // it.
-          ++I;
-          continue;
-        }
-
-        // Track the lowest link of the children, if any are still in the stack.
-        // Any child not on the stack will have a LowLink of -1.
-        assert(ChildN.LowLink != 0 &&
-               "Low-link must not be zero with a non-zero DFS number.");
-        if (ChildN.LowLink >= 0 && ChildN.LowLink < N->LowLink)
-          N->LowLink = ChildN.LowLink;
-        ++I;
-      }
-
-      // We've finished processing N and its descendants, put it on our pending
-      // stack to eventually get merged into a RefSCC.
-      PendingRefSCCStack.push_back(N);
-
-      // If this node is linked to some lower entry, continue walking up the
-      // stack.
-      if (N->LowLink != N->DFSNumber) {
-        assert(!DFSStack.empty() &&
-               "We never found a viable root for a RefSCC to pop off!");
-        continue;
-      }
-
-      // Otherwise, form a new RefSCC from the top of the pending node stack.
-      int RefSCCNumber = PostOrderNumber++;
-      int RootDFSNumber = N->DFSNumber;
-
-      // Find the range of the node stack by walking down until we pass the
-      // root DFS number. Update the DFS numbers and low link numbers in the
-      // process to avoid re-walking this list where possible.
-      auto StackRI = find_if(reverse(PendingRefSCCStack), [&](Node *N) {
-        if (N->DFSNumber < RootDFSNumber)
-          // We've found the bottom.
-          return true;
-
-        // Update this node and keep scanning.
-        N->DFSNumber = -1;
-        // Save the post-order number in the lowlink field so that we can use
-        // it to map SCCs into new RefSCCs after we finish the DFS.
-        N->LowLink = RefSCCNumber;
-        return false;
-      });
-      auto RefSCCNodes = make_range(StackRI.base(), PendingRefSCCStack.end());
-
-      // If we find a cycle containing all nodes originally in this RefSCC then
-      // the removal hasn't changed the structure at all. This is an important
-      // special case and we can directly exit the entire routine more
-      // efficiently as soon as we discover it.
-      if (llvm::size(RefSCCNodes) == NumRefSCCNodes) {
-        // Clear out the low link field as we won't need it.
-        for (Node *N : RefSCCNodes)
-          N->LowLink = -1;
-        // Return the empty result immediately.
-        return Result;
-      }
-
-      // We've already marked the nodes internally with the RefSCC number so
-      // just clear them off the stack and continue.
-      PendingRefSCCStack.erase(RefSCCNodes.begin(), PendingRefSCCStack.end());
-    } while (!DFSStack.empty());
-
-    assert(DFSStack.empty() && "Didn't flush the entire DFS stack!");
-    assert(PendingRefSCCStack.empty() && "Didn't flush all pending nodes!");
-  } while (!Worklist.empty());
-
-  assert(PostOrderNumber > 1 &&
-         "Should never finish the DFS when the existing RefSCC remains valid!");
-
-  // Otherwise we create a collection of new RefSCC nodes and build
-  // a radix-sort style map from postorder number to these new RefSCCs. We then
-  // append SCCs to each of these RefSCCs in the order they occurred in the
-  // original SCCs container.
-  for (int i = 0; i < PostOrderNumber; ++i)
-    Result.push_back(G->createRefSCC(*G));
-
-  // Insert the resulting postorder sequence into the global graph postorder
-  // sequence before the current RefSCC in that sequence, and then remove the
-  // current one.
-  //
-  // FIXME: It'd be nice to change the APIs so that we returned an iterator
-  // range over the global postorder sequence and generally use that sequence
-  // rather than building a separate result vector here.
-  int Idx = G->getRefSCCIndex(*this);
-  G->PostOrderRefSCCs.erase(G->PostOrderRefSCCs.begin() + Idx);
-  G->PostOrderRefSCCs.insert(G->PostOrderRefSCCs.begin() + Idx, Result.begin(),
-                             Result.end());
-  for (int i : seq<int>(Idx, G->PostOrderRefSCCs.size()))
-    G->RefSCCIndices[G->PostOrderRefSCCs[i]] = i;
-
-  for (SCC *C : SCCs) {
-    // We store the SCC number in the node's low-link field above.
-    int SCCNumber = C->begin()->LowLink;
-    // Clear out all of the SCC's node's low-link fields now that we're done
-    // using them as side-storage.
-    for (Node &N : *C) {
-      assert(N.LowLink == SCCNumber &&
-             "Cannot have different numbers for nodes in the same SCC!");
-      N.LowLink = -1;
-    }
-
-    RefSCC &RC = *Result[SCCNumber];
-    int SCCIndex = RC.SCCs.size();
-    RC.SCCs.push_back(C);
-    RC.SCCIndices[C] = SCCIndex;
-    C->OuterRefSCC = &RC;
-  }
-
-  // Now that we've moved things into the new RefSCCs, clear out our current
-  // one.
-  G = nullptr;
-  SCCs.clear();
-  SCCIndices.clear();
-
-#ifdef EXPENSIVE_CHECKS
-  // Verify the new RefSCCs we've built.
-  for (RefSCC *RC : Result)
-    RC->verify();
-#endif
-
-  // Return the new list of SCCs.
-  return Result;
-}
-
-void LazyCallGraph::RefSCC::insertTrivialCallEdge(Node &SourceN,
-                                                  Node &TargetN) {
-#ifdef EXPENSIVE_CHECKS
-  auto ExitVerifier = make_scope_exit([this] { verify(); });
-
-  // Check that we aren't breaking some invariants of the SCC graph. Note that
-  // this is quadratic in the number of edges in the call graph!
-  SCC &SourceC = *G->lookupSCC(SourceN);
-  SCC &TargetC = *G->lookupSCC(TargetN);
-  if (&SourceC != &TargetC)
-    assert(SourceC.isAncestorOf(TargetC) &&
-           "Call edge is not trivial in the SCC graph!");
-#endif
-
-  // First insert it into the source or find the existing edge.
-  auto InsertResult =
-      SourceN->EdgeIndexMap.insert({&TargetN, SourceN->Edges.size()});
-  if (!InsertResult.second) {
-    // Already an edge, just update it.
-    Edge &E = SourceN->Edges[InsertResult.first->second];
-    if (E.isCall())
-      return; // Nothing to do!
-    E.setKind(Edge::Call);
-  } else {
-    // Create the new edge.
-    SourceN->Edges.emplace_back(TargetN, Edge::Call);
-  }
-}
-
-void LazyCallGraph::RefSCC::insertTrivialRefEdge(Node &SourceN, Node &TargetN) {
-#ifdef EXPENSIVE_CHECKS
-  auto ExitVerifier = make_scope_exit([this] { verify(); });
-
-  // Check that we aren't breaking some invariants of the RefSCC graph.
-  RefSCC &SourceRC = *G->lookupRefSCC(SourceN);
-  RefSCC &TargetRC = *G->lookupRefSCC(TargetN);
-  if (&SourceRC != &TargetRC)
-    assert(SourceRC.isAncestorOf(TargetRC) &&
-           "Ref edge is not trivial in the RefSCC graph!");
-#endif
-
-  // First insert it into the source or find the existing edge.
-  auto InsertResult =
-      SourceN->EdgeIndexMap.insert({&TargetN, SourceN->Edges.size()});
-  if (!InsertResult.second)
-    // Already an edge, we're done.
-    return;
-
-  // Create the new edge.
-  SourceN->Edges.emplace_back(TargetN, Edge::Ref);
-}
-
-void LazyCallGraph::RefSCC::replaceNodeFunction(Node &N, Function &NewF) {
-  Function &OldF = N.getFunction();
-
-#ifdef EXPENSIVE_CHECKS
-  auto ExitVerifier = make_scope_exit([this] { verify(); });
-
-  assert(G->lookupRefSCC(N) == this &&
-         "Cannot replace the function of a node outside this RefSCC.");
-
-  assert(G->NodeMap.find(&NewF) == G->NodeMap.end() &&
-         "Must not have already walked the new function!'");
-
-  // It is important that this replacement not introduce graph changes so we
-  // insist that the caller has already removed every use of the original
-  // function and that all uses of the new function correspond to existing
-  // edges in the graph. The common and expected way to use this is when
-  // replacing the function itself in the IR without changing the call graph
-  // shape and just updating the analysis based on that.
-  assert(&OldF != &NewF && "Cannot replace a function with itself!");
-  assert(OldF.use_empty() &&
-         "Must have moved all uses from the old function to the new!");
-#endif
-
-  N.replaceFunction(NewF);
-
-  // Update various call graph maps.
-  G->NodeMap.erase(&OldF);
-  G->NodeMap[&NewF] = &N;
-}
-
-void LazyCallGraph::insertEdge(Node &SourceN, Node &TargetN, Edge::Kind EK) {
-  assert(SCCMap.empty() &&
-         "This method cannot be called after SCCs have been formed!");
-
-  return SourceN->insertEdgeInternal(TargetN, EK);
-}
-
-void LazyCallGraph::removeEdge(Node &SourceN, Node &TargetN) {
-  assert(SCCMap.empty() &&
-         "This method cannot be called after SCCs have been formed!");
-
-  bool Removed = SourceN->removeEdgeInternal(TargetN);
-  (void)Removed;
-  assert(Removed && "Target not in the edge set for this caller?");
-}
-
-void LazyCallGraph::removeDeadFunction(Function &F) {
-  // FIXME: This is unnecessarily restrictive. We should be able to remove
-  // functions which recursively call themselves.
-  assert(F.hasZeroLiveUses() &&
-         "This routine should only be called on trivially dead functions!");
-
-  // We shouldn't remove library functions as they are never really dead while
-  // the call graph is in use -- every function definition refers to them.
-  assert(!isLibFunction(F) &&
-         "Must not remove lib functions from the call graph!");
-
-  auto NI = NodeMap.find(&F);
-  if (NI == NodeMap.end())
-    // Not in the graph at all!
-    return;
-
-  Node &N = *NI->second;
-  NodeMap.erase(NI);
-
-  // Remove this from the entry edges if present.
-  EntryEdges.removeEdgeInternal(N);
-
-  // Cannot remove a function which has yet to be visited in the DFS walk, so
-  // if we have a node at all then we must have an SCC and RefSCC.
-  auto CI = SCCMap.find(&N);
-  assert(CI != SCCMap.end() &&
-         "Tried to remove a node without an SCC after DFS walk started!");
-  SCC &C = *CI->second;
-  SCCMap.erase(CI);
-  RefSCC &RC = C.getOuterRefSCC();
-
-  // This node must be the only member of its SCC as it has no callers, and
-  // that SCC must be the only member of a RefSCC as it has no references.
-  // Validate these properties first.
-  assert(C.size() == 1 && "Dead functions must be in a singular SCC");
-  assert(RC.size() == 1 && "Dead functions must be in a singular RefSCC");
-
-  // Finally clear out all the data structures from the node down through the
-  // components. postorder_ref_scc_iterator will skip empty RefSCCs, so no need
-  // to adjust LazyCallGraph data structures.
-  N.clear();
-  N.G = nullptr;
-  N.F = nullptr;
-  C.clear();
-  RC.clear();
-  RC.G = nullptr;
-
-  // Nothing to delete as all the objects are allocated in stable bump pointer
-  // allocators.
-}
-
-// Gets the Edge::Kind from one function to another by looking at the function's
-// instructions. Asserts if there is no edge.
-// Useful for determining what type of edge should exist between functions when
-// the edge hasn't been created yet.
-static LazyCallGraph::Edge::Kind getEdgeKind(Function &OriginalFunction,
-                                             Function &NewFunction) {
-  // In release builds, assume that if there are no direct calls to the new
-  // function, then there is a ref edge. In debug builds, keep track of
-  // references to assert that there is actually a ref edge if there is no call
-  // edge.
-#ifndef NDEBUG
-  SmallVector<Constant *, 16> Worklist;
-  SmallPtrSet<Constant *, 16> Visited;
-#endif
-
-  for (Instruction &I : instructions(OriginalFunction)) {
-    if (auto *CB = dyn_cast<CallBase>(&I)) {
-      if (Function *Callee = CB->getCalledFunction()) {
-        if (Callee == &NewFunction)
-          return LazyCallGraph::Edge::Kind::Call;
-      }
-    }
-#ifndef NDEBUG
-    for (Value *Op : I.operand_values()) {
-      if (Constant *C = dyn_cast<Constant>(Op)) {
-        if (Visited.insert(C).second)
-          Worklist.push_back(C);
-      }
-    }
-#endif
-  }
-
-#ifndef NDEBUG
-  bool FoundNewFunction = false;
-  LazyCallGraph::visitReferences(Worklist, Visited, [&](Function &F) {
-    if (&F == &NewFunction)
-      FoundNewFunction = true;
-  });
-  assert(FoundNewFunction && "No edge from original function to new function");
-#endif
-
-  return LazyCallGraph::Edge::Kind::Ref;
-}
-
-void LazyCallGraph::addSplitFunction(Function &OriginalFunction,
-                                     Function &NewFunction) {
-  assert(lookup(OriginalFunction) &&
-         "Original function's node should already exist");
-  Node &OriginalN = get(OriginalFunction);
-  SCC *OriginalC = lookupSCC(OriginalN);
-  RefSCC *OriginalRC = lookupRefSCC(OriginalN);
-
-#ifdef EXPENSIVE_CHECKS
-  OriginalRC->verify();
-  auto VerifyOnExit = make_scope_exit([&]() { OriginalRC->verify(); });
-#endif
-
-  assert(!lookup(NewFunction) &&
-         "New function's node should not already exist");
-  Node &NewN = initNode(NewFunction);
-
-  Edge::Kind EK = getEdgeKind(OriginalFunction, NewFunction);
-
-  SCC *NewC = nullptr;
-  for (Edge &E : *NewN) {
-    Node &EN = E.getNode();
-    if (EK == Edge::Kind::Call && E.isCall() && lookupSCC(EN) == OriginalC) {
-      // If the edge to the new function is a call edge and there is a call edge
-      // from the new function to any function in the original function's SCC,
-      // it is in the same SCC (and RefSCC) as the original function.
-      NewC = OriginalC;
-      NewC->Nodes.push_back(&NewN);
-      break;
-    }
-  }
-
-  if (!NewC) {
-    for (Edge &E : *NewN) {
-      Node &EN = E.getNode();
-      if (lookupRefSCC(EN) == OriginalRC) {
-        // If there is any edge from the new function to any function in the
-        // original function's RefSCC, it is in the same RefSCC as the original
-        // function but a new SCC.
-        RefSCC *NewRC = OriginalRC;
-        NewC = createSCC(*NewRC, SmallVector<Node *, 1>({&NewN}));
-
-        // The new function's SCC is not the same as the original function's
-        // SCC, since that case was handled earlier. If the edge from the
-        // original function to the new function was a call edge, then we need
-        // to insert the newly created function's SCC before the original
-        // function's SCC. Otherwise either the new SCC comes after the original
-        // function's SCC, or it doesn't matter, and in both cases we can add it
-        // to the very end.
-        int InsertIndex = EK == Edge::Kind::Call ? NewRC->SCCIndices[OriginalC]
-                                                 : NewRC->SCCIndices.size();
-        NewRC->SCCs.insert(NewRC->SCCs.begin() + InsertIndex, NewC);
-        for (int I = InsertIndex, Size = NewRC->SCCs.size(); I < Size; ++I)
-          NewRC->SCCIndices[NewRC->SCCs[I]] = I;
-
-        break;
-      }
-    }
-  }
-
-  if (!NewC) {
-    // We didn't find any edges back to the original function's RefSCC, so the
-    // new function belongs in a new RefSCC. The new RefSCC goes before the
-    // original function's RefSCC.
-    RefSCC *NewRC = createRefSCC(*this);
-    NewC = createSCC(*NewRC, SmallVector<Node *, 1>({&NewN}));
-    NewRC->SCCIndices[NewC] = 0;
-    NewRC->SCCs.push_back(NewC);
-    auto OriginalRCIndex = RefSCCIndices.find(OriginalRC)->second;
-    PostOrderRefSCCs.insert(PostOrderRefSCCs.begin() + OriginalRCIndex, NewRC);
-    for (int I = OriginalRCIndex, Size = PostOrderRefSCCs.size(); I < Size; ++I)
-      RefSCCIndices[PostOrderRefSCCs[I]] = I;
-  }
-
-  SCCMap[&NewN] = NewC;
-
-  OriginalN->insertEdgeInternal(NewN, EK);
-}
-
-void LazyCallGraph::addSplitRefRecursiveFunctions(
-    Function &OriginalFunction, ArrayRef<Function *> NewFunctions) {
-  assert(!NewFunctions.empty() && "Can't add zero functions");
-  assert(lookup(OriginalFunction) &&
-         "Original function's node should already exist");
-  Node &OriginalN = get(OriginalFunction);
-  RefSCC *OriginalRC = lookupRefSCC(OriginalN);
-
-#ifdef EXPENSIVE_CHECKS
-  OriginalRC->verify();
-  auto VerifyOnExit = make_scope_exit([&]() {
-    OriginalRC->verify();
-    for (Function *NewFunction : NewFunctions)
-      lookupRefSCC(get(*NewFunction))->verify();
-  });
-#endif
-
-  bool ExistsRefToOriginalRefSCC = false;
-
-  for (Function *NewFunction : NewFunctions) {
-    Node &NewN = initNode(*NewFunction);
-
-    OriginalN->insertEdgeInternal(NewN, Edge::Kind::Ref);
-
-    // Check if there is any edge from any new function back to any function in
-    // the original function's RefSCC.
-    for (Edge &E : *NewN) {
-      if (lookupRefSCC(E.getNode()) == OriginalRC) {
-        ExistsRefToOriginalRefSCC = true;
-        break;
-      }
-    }
-  }
-
-  RefSCC *NewRC;
-  if (ExistsRefToOriginalRefSCC) {
-    // If there is any edge from any new function to any function in the
-    // original function's RefSCC, all new functions will be in the same RefSCC
-    // as the original function.
-    NewRC = OriginalRC;
-  } else {
-    // Otherwise the new functions are in their own RefSCC.
-    NewRC = createRefSCC(*this);
-    // The new RefSCC goes before the original function's RefSCC in postorder
-    // since there are only edges from the original function's RefSCC to the new
-    // RefSCC.
-    auto OriginalRCIndex = RefSCCIndices.find(OriginalRC)->second;
-    PostOrderRefSCCs.insert(PostOrderRefSCCs.begin() + OriginalRCIndex, NewRC);
-    for (int I = OriginalRCIndex, Size = PostOrderRefSCCs.size(); I < Size; ++I)
-      RefSCCIndices[PostOrderRefSCCs[I]] = I;
-  }
-
-  for (Function *NewFunction : NewFunctions) {
-    Node &NewN = get(*NewFunction);
-    // Each new function is in its own new SCC. The original function can only
-    // have a ref edge to new functions, and no other existing functions can
-    // have references to new functions. Each new function only has a ref edge
-    // to the other new functions.
-    SCC *NewC = createSCC(*NewRC, SmallVector<Node *, 1>({&NewN}));
-    // The new SCCs are either sibling SCCs or parent SCCs to all other existing
-    // SCCs in the RefSCC. Either way, they can go at the back of the postorder
-    // SCC list.
-    auto Index = NewRC->SCCIndices.size();
-    NewRC->SCCIndices[NewC] = Index;
-    NewRC->SCCs.push_back(NewC);
-    SCCMap[&NewN] = NewC;
-  }
-
-#ifndef NDEBUG
-  for (Function *F1 : NewFunctions) {
-    assert(getEdgeKind(OriginalFunction, *F1) == Edge::Kind::Ref &&
-           "Expected ref edges from original function to every new function");
-    Node &N1 = get(*F1);
-    for (Function *F2 : NewFunctions) {
-      if (F1 == F2)
-        continue;
-      Node &N2 = get(*F2);
-      assert(!N1->lookup(N2)->isCall() &&
-             "Edges between new functions must be ref edges");
-    }
-  }
-#endif
-}
-
-LazyCallGraph::Node &LazyCallGraph::insertInto(Function &F, Node *&MappedN) {
-  return *new (MappedN = BPA.Allocate()) Node(*this, F);
-}
-
-void LazyCallGraph::updateGraphPtrs() {
-  // Walk the node map to update their graph pointers. While this iterates in
-  // an unstable order, the order has no effect so it remains correct.
-  for (auto &FunctionNodePair : NodeMap)
-    FunctionNodePair.second->G = this;
-
-  for (auto *RC : PostOrderRefSCCs)
-    RC->G = this;
-}
-
-LazyCallGraph::Node &LazyCallGraph::initNode(Function &F) {
-  Node &N = get(F);
-  N.DFSNumber = N.LowLink = -1;
-  N.populate();
-  NodeMap[&F] = &N;
-  return N;
-}
-
-template <typename RootsT, typename GetBeginT, typename GetEndT,
-          typename GetNodeT, typename FormSCCCallbackT>
-void LazyCallGraph::buildGenericSCCs(RootsT &&Roots, GetBeginT &&GetBegin,
-                                     GetEndT &&GetEnd, GetNodeT &&GetNode,
-                                     FormSCCCallbackT &&FormSCC) {
-  using EdgeItT = decltype(GetBegin(std::declval<Node &>()));
-
-  SmallVector<std::pair<Node *, EdgeItT>, 16> DFSStack;
-  SmallVector<Node *, 16> PendingSCCStack;
-
-  // Scan down the stack and DFS across the call edges.
-  for (Node *RootN : Roots) {
-    assert(DFSStack.empty() &&
-           "Cannot begin a new root with a non-empty DFS stack!");
-    assert(PendingSCCStack.empty() &&
-           "Cannot begin a new root with pending nodes for an SCC!");
-
-    // Skip any nodes we've already reached in the DFS.
-    if (RootN->DFSNumber != 0) {
-      assert(RootN->DFSNumber == -1 &&
-             "Shouldn't have any mid-DFS root nodes!");
-      continue;
-    }
-
-    RootN->DFSNumber = RootN->LowLink = 1;
-    int NextDFSNumber = 2;
-
-    DFSStack.push_back({RootN, GetBegin(*RootN)});
-    do {
-      Node *N;
-      EdgeItT I;
-      std::tie(N, I) = DFSStack.pop_back_val();
-      auto E = GetEnd(*N);
-      while (I != E) {
-        Node &ChildN = GetNode(I);
-        if (ChildN.DFSNumber == 0) {
-          // We haven't yet visited this child, so descend, pushing the current
-          // node onto the stack.
-          DFSStack.push_back({N, I});
-
-          ChildN.DFSNumber = ChildN.LowLink = NextDFSNumber++;
-          N = &ChildN;
-          I = GetBegin(*N);
-          E = GetEnd(*N);
-          continue;
-        }
-
-        // If the child has already been added to some child component, it
-        // couldn't impact the low-link of this parent because it isn't
-        // connected, and thus its low-link isn't relevant so skip it.
-        if (ChildN.DFSNumber == -1) {
-          ++I;
-          continue;
-        }
-
-        // Track the lowest linked child as the lowest link for this node.
-        assert(ChildN.LowLink > 0 && "Must have a positive low-link number!");
-        if (ChildN.LowLink < N->LowLink)
-          N->LowLink = ChildN.LowLink;
-
-        // Move to the next edge.
-        ++I;
-      }
-
-      // We've finished processing N and its descendants, put it on our pending
-      // SCC stack to eventually get merged into an SCC of nodes.
-      PendingSCCStack.push_back(N);
-
-      // If this node is linked to some lower entry, continue walking up the
-      // stack.
-      if (N->LowLink != N->DFSNumber)
-        continue;
-
-      // Otherwise, we've completed an SCC. Append it to our post order list of
-      // SCCs.
-      int RootDFSNumber = N->DFSNumber;
-      // Find the range of the node stack by walking down until we pass the
-      // root DFS number.
-      auto SCCNodes = make_range(
-          PendingSCCStack.rbegin(),
-          find_if(reverse(PendingSCCStack), [RootDFSNumber](const Node *N) {
-            return N->DFSNumber < RootDFSNumber;
-          }));
-      // Form a new SCC out of these nodes and then clear them off our pending
-      // stack.
-      FormSCC(SCCNodes);
-      PendingSCCStack.erase(SCCNodes.end().base(), PendingSCCStack.end());
-    } while (!DFSStack.empty());
-  }
-}
-
-/// Build the internal SCCs for a RefSCC from a sequence of nodes.
-///
-/// Appends the SCCs to the provided vector and updates the map with their
-/// indices. Both the vector and map must be empty when passed into this
-/// routine.
-void LazyCallGraph::buildSCCs(RefSCC &RC, node_stack_range Nodes) {
-  assert(RC.SCCs.empty() && "Already built SCCs!");
-  assert(RC.SCCIndices.empty() && "Already mapped SCC indices!");
-
-  for (Node *N : Nodes) {
-    assert(N->LowLink >= (*Nodes.begin())->LowLink &&
-           "We cannot have a low link in an SCC lower than its root on the "
-           "stack!");
-
-    // This node will go into the next RefSCC, clear out its DFS and low link
-    // as we scan.
-    N->DFSNumber = N->LowLink = 0;
-  }
-
-  // Each RefSCC contains a DAG of the call SCCs. To build these, we do
-  // a direct walk of the call edges using Tarjan's algorithm. We reuse the
-  // internal storage as we won't need it for the outer graph's DFS any longer.
-  buildGenericSCCs(
-      Nodes, [](Node &N) { return N->call_begin(); },
-      [](Node &N) { return N->call_end(); },
-      [](EdgeSequence::call_iterator I) -> Node & { return I->getNode(); },
-      [this, &RC](node_stack_range Nodes) {
-        RC.SCCs.push_back(createSCC(RC, Nodes));
-        for (Node &N : *RC.SCCs.back()) {
-          N.DFSNumber = N.LowLink = -1;
-          SCCMap[&N] = RC.SCCs.back();
-        }
-      });
-
-  // Wire up the SCC indices.
-  for (int i = 0, Size = RC.SCCs.size(); i < Size; ++i)
-    RC.SCCIndices[RC.SCCs[i]] = i;
-}
-
-void LazyCallGraph::buildRefSCCs() {
-  if (EntryEdges.empty() || !PostOrderRefSCCs.empty())
-    // RefSCCs are either non-existent or already built!
-    return;
-
-  assert(RefSCCIndices.empty() && "Already mapped RefSCC indices!");
-
-  SmallVector<Node *, 16> Roots;
-  for (Edge &E : *this)
-    Roots.push_back(&E.getNode());
-
-  // The roots will be iterated in order.
-  buildGenericSCCs(
-      Roots,
-      [](Node &N) {
-        // We need to populate each node as we begin to walk its edges.
-        N.populate();
-        return N->begin();
-      },
-      [](Node &N) { return N->end(); },
-      [](EdgeSequence::iterator I) -> Node & { return I->getNode(); },
-      [this](node_stack_range Nodes) {
-        RefSCC *NewRC = createRefSCC(*this);
-        buildSCCs(*NewRC, Nodes);
-
-        // Push the new node into the postorder list and remember its position
-        // in the index map.
-        bool Inserted =
-            RefSCCIndices.insert({NewRC, PostOrderRefSCCs.size()}).second;
-        (void)Inserted;
-        assert(Inserted && "Cannot already have this RefSCC in the index map!");
-        PostOrderRefSCCs.push_back(NewRC);
-#ifdef EXPENSIVE_CHECKS
-        NewRC->verify();
-#endif
-      });
-}
-
-void LazyCallGraph::visitReferences(SmallVectorImpl<Constant *> &Worklist,
-                                    SmallPtrSetImpl<Constant *> &Visited,
-                                    function_ref<void(Function &)> Callback) {
-  while (!Worklist.empty()) {
-    Constant *C = Worklist.pop_back_val();
-
-    if (Function *F = dyn_cast<Function>(C)) {
-      if (!F->isDeclaration())
-        Callback(*F);
-      continue;
-    }
-
-    // blockaddresses are weird and don't participate in the call graph anyway,
-    // skip them.
-    if (isa<BlockAddress>(C))
-      continue;
-
-    for (Value *Op : C->operand_values())
-      if (Visited.insert(cast<Constant>(Op)).second)
-        Worklist.push_back(cast<Constant>(Op));
-  }
-}
-
-AnalysisKey LazyCallGraphAnalysis::Key;
-
-LazyCallGraphPrinterPass::LazyCallGraphPrinterPass(raw_ostream &OS) : OS(OS) {}
-
-static void printNode(raw_ostream &OS, LazyCallGraph::Node &N) {
-  OS << "  Edges in function: " << N.getFunction().getName() << "\n";
-  for (LazyCallGraph::Edge &E : N.populate())
-    OS << "    " << (E.isCall() ? "call" : "ref ") << " -> "
-       << E.getFunction().getName() << "\n";
-
-  OS << "\n";
-}
-
-static void printSCC(raw_ostream &OS, LazyCallGraph::SCC &C) {
-  OS << "    SCC with " << C.size() << " functions:\n";
-
-  for (LazyCallGraph::Node &N : C)
-    OS << "      " << N.getFunction().getName() << "\n";
-}
-
-static void printRefSCC(raw_ostream &OS, LazyCallGraph::RefSCC &C) {
-  OS << "  RefSCC with " << C.size() << " call SCCs:\n";
-
-  for (LazyCallGraph::SCC &InnerC : C)
-    printSCC(OS, InnerC);
-
-  OS << "\n";
-}
-
-PreservedAnalyses LazyCallGraphPrinterPass::run(Module &M,
-                                                ModuleAnalysisManager &AM) {
-  LazyCallGraph &G = AM.getResult<LazyCallGraphAnalysis>(M);
-
-  OS << "Printing the call graph for module: " << M.getModuleIdentifier()
-     << "\n\n";
-
-  for (Function &F : M)
-    printNode(OS, G.get(F));
-
-  G.buildRefSCCs();
-  for (LazyCallGraph::RefSCC &C : G.postorder_ref_sccs())
-    printRefSCC(OS, C);
-
-  return PreservedAnalyses::all();
-}
-
-LazyCallGraphDOTPrinterPass::LazyCallGraphDOTPrinterPass(raw_ostream &OS)
-    : OS(OS) {}
-
-static void printNodeDOT(raw_ostream &OS, LazyCallGraph::Node &N) {
-  std::string Name =
-      "\"" + DOT::EscapeString(std::string(N.getFunction().getName())) + "\"";
-
-  for (LazyCallGraph::Edge &E : N.populate()) {
-    OS << "  " << Name << " -> \""
-       << DOT::EscapeString(std::string(E.getFunction().getName())) << "\"";
-    if (!E.isCall()) // It is a ref edge.
-      OS << " [style=dashed,label=\"ref\"]";
-    OS << ";\n";
-  }
-
-  OS << "\n";
-}
-
-PreservedAnalyses LazyCallGraphDOTPrinterPass::run(Module &M,
-                                                   ModuleAnalysisManager &AM) {
-  LazyCallGraph &G = AM.getResult<LazyCallGraphAnalysis>(M);
-
-  OS << "digraph \"" << DOT::EscapeString(M.getModuleIdentifier()) << "\" {\n";
-
-  for (Function &F : M)
-    printNodeDOT(OS, G.get(F));
-
-  OS << "}\n";
-
-  return PreservedAnalyses::all();
-}