6 files changed, 670 insertions, 0 deletions

diff --git a/include/llvm/Analysis/LazyCallGraph.h b/include/llvm/Analysis/LazyCallGraph.h
new file mode 100644
index 0000000000..d355b9cf5a
--- /dev/null
+++ b/include/llvm/Analysis/LazyCallGraph.h
@@ -0,0 +1,337 @@
+//===- LazyCallGraph.h - Analysis of a Module's call graph ------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+///
+/// Implements a lazy call graph analysis and related passes for the new pass
+/// manager.
+///
+/// NB: This is *not* a traditional call graph! It is a graph which models both
+/// the current calls and potential calls. As a consequence there are many
+/// edges in this call graph that do not correspond to a 'call' or 'invoke'
+/// instruction.
+///
+/// The primary use cases of this graph analysis is to facilitate iterating
+/// across the functions of a module in ways that ensure all callees are
+/// visited prior to a caller (given any SCC constraints), or vice versa. As
+/// such is it particularly well suited to organizing CGSCC optimizations such
+/// as inlining, outlining, argument promotion, etc. That is its primary use
+/// case and motivates the design. It may not be appropriate for other
+/// purposes. The use graph of functions or some other conservative analysis of
+/// call instructions may be interesting for optimizations and subsequent
+/// analyses which don't work in the context of an overly specified
+/// potential-call-edge graph.
+///
+/// To understand the specific rules and nature of this call graph analysis,
+/// see the documentation of the \c LazyCallGraph below.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_LAZY_CALL_GRAPH
+#define LLVM_ANALYSIS_LAZY_CALL_GRAPH
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/PointerUnion.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/Support/Allocator.h"
+#include <iterator>
+
+namespace llvm {
+class ModuleAnalysisManager;
+class PreservedAnalyses;
+class raw_ostream;
+
+/// \brief A lazily constructed view of the call graph of a module.
+///
+/// With the edges of this graph, the motivating constraint that we are
+/// attempting to maintain is that function-local optimization, CGSCC-local
+/// optimizations, and optimizations transforming a pair of functions connected
+/// by an edge in the graph, do not invalidate a bottom-up traversal of the SCC
+/// DAG. That is, no optimizations will delete, remove, or add an edge such
+/// that functions already visited in a bottom-up order of the SCC DAG are no
+/// longer valid to have visited, or such that functions not yet visited in
+/// a bottom-up order of the SCC DAG are not required to have already been
+/// visited.
+///
+/// Within this constraint, the desire is to minimize the merge points of the
+/// SCC DAG. The greater the fanout of the SCC DAG and the fewer merge points
+/// in the SCC DAG, the more independence there is in optimizing within it.
+/// There is a strong desire to enable parallelization of optimizations over
+/// the call graph, and both limited fanout and merge points will (artificially
+/// in some cases) limit the scaling of such an effort.
+///
+/// To this end, graph represents both direct and any potential resolution to
+/// an indirect call edge. Another way to think about it is that it represents
+/// both the direct call edges and any direct call edges that might be formed
+/// through static optimizations. Specifically, it considers taking the address
+/// of a function to be an edge in the call graph because this might be
+/// forwarded to become a direct call by some subsequent function-local
+/// optimization. The result is that the graph closely follows the use-def
+/// edges for functions. Walking "up" the graph can be done by looking at all
+/// of the uses of a function.
+///
+/// The roots of the call graph are the external functions and functions
+/// escaped into global variables. Those functions can be called from outside
+/// of the module or via unknowable means in the IR -- we may not be able to
+/// form even a potential call edge from a function body which may dynamically
+/// load the function and call it.
+///
+/// This analysis still requires updates to remain valid after optimizations
+/// which could potentially change the set of potential callees. The
+/// constraints it operates under only make the traversal order remain valid.
+///
+/// The entire analysis must be re-computed if full interprocedural
+/// optimizations run at any point. For example, globalopt completely
+/// invalidates the information in this analysis.
+///
+/// FIXME: This class is named LazyCallGraph in a lame attempt to distinguish
+/// it from the existing CallGraph. At some point, it is expected that this
+/// will be the only call graph and it will be renamed accordingly.
+class LazyCallGraph {
+public:
+  class Node;
+  typedef SmallVector<PointerUnion<Function *, Node *>, 4> NodeVectorT;
+  typedef SmallVectorImpl<PointerUnion<Function *, Node *> > NodeVectorImplT;
+
+  /// \brief A lazy iterator used for both the entry nodes and child nodes.
+  ///
+  /// When this iterator is dereferenced, if not yet available, a function will
+  /// be scanned for "calls" or uses of functions and its child information
+  /// will be constructed. All of these results are accumulated and cached in
+  /// the graph.
+  class iterator : public std::iterator<std::bidirectional_iterator_tag, Node *,
+                                        ptrdiff_t, Node *, Node *> {
+    friend class LazyCallGraph;
+    friend class LazyCallGraph::Node;
+    typedef std::iterator<std::bidirectional_iterator_tag, Node *, ptrdiff_t,
+                          Node *, Node *> BaseT;
+
+    /// \brief Nonce type to select the constructor for the end iterator.
+    struct IsAtEndT {};
+
+    LazyCallGraph &G;
+    NodeVectorImplT::iterator NI;
+
+    // Build the begin iterator for a node.
+    explicit iterator(LazyCallGraph &G, NodeVectorImplT &Nodes)
+        : G(G), NI(Nodes.begin()) {}
+
+    // Build the end iterator for a node. This is selected purely by overload.
+    iterator(LazyCallGraph &G, NodeVectorImplT &Nodes, IsAtEndT /*Nonce*/)
+        : G(G), NI(Nodes.end()) {}
+
+  public:
+    iterator(const iterator &Arg) : G(Arg.G), NI(Arg.NI) {}
+
+    iterator &operator=(iterator Arg) {
+      std::swap(Arg, *this);
+      return *this;
+    }
+
+    bool operator==(const iterator &Arg) { return NI == Arg.NI; }
+    bool operator!=(const iterator &Arg) { return !operator==(Arg); }
+
+    reference operator*() const {
+      if (NI->is<Node *>())
+        return NI->get<Node *>();
+
+      Function *F = NI->get<Function *>();
+      Node *ChildN = G.get(*F);
+      *NI = ChildN;
+      return ChildN;
+    }
+    pointer operator->() const { return operator*(); }
+
+    iterator &operator++() {
+      ++NI;
+      return *this;
+    }
+    iterator operator++(int) {
+      iterator prev = *this;
+      ++*this;
+      return prev;
+    }
+
+    iterator &operator--() {
+      --NI;
+      return *this;
+    }
+    iterator operator--(int) {
+      iterator next = *this;
+      --*this;
+      return next;
+    }
+  };
+
+  /// \brief Construct a graph for the given module.
+  ///
+  /// This sets up the graph and computes all of the entry points of the graph.
+  /// No function definitions are scanned until their nodes in the graph are
+  /// requested during traversal.
+  LazyCallGraph(Module &M);
+
+  /// \brief Copy constructor.
+  ///
+  /// This does a deep copy of the graph. It does no verification that the
+  /// graph remains valid for the module. It is also relatively expensive.
+  LazyCallGraph(const LazyCallGraph &G);
+
+#if LLVM_HAS_RVALUE_REFERENCES
+  /// \brief Move constructor.
+  ///
+  /// This is a deep move. It leaves G in an undefined but destroyable state.
+  /// Any other operation on G is likely to fail.
+  LazyCallGraph(LazyCallGraph &&G);
+#endif
+
+  iterator begin() { return iterator(*this, EntryNodes); }
+  iterator end() { return iterator(*this, EntryNodes, iterator::IsAtEndT()); }
+
+  /// \brief Lookup a function in the graph which has already been scanned and
+  /// added.
+  Node *lookup(const Function &F) const { return NodeMap.lookup(&F); }
+
+  /// \brief Get a graph node for a given function, scanning it to populate the
+  /// graph data as necessary.
+  Node *get(Function &F) {
+    Node *&N = NodeMap[&F];
+    if (N)
+      return N;
+
+    return insertInto(F, N);
+  }
+
+private:
+  Module &M;
+
+  /// \brief Allocator that holds all the call graph nodes.
+  SpecificBumpPtrAllocator<Node> BPA;
+
+  /// \brief Maps function->node for fast lookup.
+  DenseMap<const Function *, Node *> NodeMap;
+
+  /// \brief The entry nodes to the graph.
+  ///
+  /// These nodes are reachable through "external" means. Put another way, they
+  /// escape at the module scope.
+  NodeVectorT EntryNodes;
+
+  /// \brief Set of the entry nodes to the graph.
+  SmallPtrSet<Function *, 4> EntryNodeSet;
+
+  /// \brief Helper to insert a new function, with an already looked-up entry in
+  /// the NodeMap.
+  Node *insertInto(Function &F, Node *&MappedN);
+
+  /// \brief Helper to copy a node from another graph into this one.
+  Node *copyInto(const Node &OtherN);
+
+#if LLVM_HAS_RVALUE_REFERENCES
+  /// \brief Helper to move a node from another graph into this one.
+  Node *moveInto(Node &&OtherN);
+#endif
+};
+
+/// \brief A node in the call graph.
+///
+/// This represents a single node. It's primary roles are to cache the list of
+/// callees, de-duplicate and provide fast testing of whether a function is
+/// a callee, and facilitate iteration of child nodes in the graph.
+class LazyCallGraph::Node {
+  friend LazyCallGraph;
+
+  LazyCallGraph &G;
+  Function &F;
+  mutable NodeVectorT Callees;
+  SmallPtrSet<Function *, 4> CalleeSet;
+
+  /// \brief Basic constructor implements the scanning of F into Callees and
+  /// CalleeSet.
+  Node(LazyCallGraph &G, Function &F);
+
+  /// \brief Constructor used when copying a node from one graph to another.
+  Node(LazyCallGraph &G, const Node &OtherN);
+
+#if LLVM_HAS_RVALUE_REFERENCES
+  /// \brief Constructor used when moving a node from one graph to another.
+  Node(LazyCallGraph &G, Node &&OtherN);
+#endif
+
+public:
+  typedef LazyCallGraph::iterator iterator;
+
+  Function &getFunction() const {
+    return F;
+  };
+
+  iterator begin() const { return iterator(G, Callees); }
+  iterator end() const { return iterator(G, Callees, iterator::IsAtEndT()); }
+
+  /// Equality is defined as address equality.
+  bool operator==(const Node &N) const { return this == &N; }
+  bool operator!=(const Node &N) const { return !operator==(N); }
+};
+
+// Provide GraphTraits specializations for call graphs.
+template <> struct GraphTraits<LazyCallGraph::Node *> {
+  typedef LazyCallGraph::Node NodeType;
+  typedef LazyCallGraph::iterator ChildIteratorType;
+
+  static NodeType *getEntryNode(NodeType *N) { return N; }
+  static ChildIteratorType child_begin(NodeType *N) { return N->begin(); }
+  static ChildIteratorType child_end(NodeType *N) { return N->end(); }
+};
+template <> struct GraphTraits<LazyCallGraph *> {
+  typedef LazyCallGraph::Node NodeType;
+  typedef LazyCallGraph::iterator ChildIteratorType;
+
+  static NodeType *getEntryNode(NodeType *N) { return N; }
+  static ChildIteratorType child_begin(NodeType *N) { return N->begin(); }
+  static ChildIteratorType child_end(NodeType *N) { return N->end(); }
+};
+
+/// \brief An analysis pass which computes the call graph for a module.
+class LazyCallGraphAnalysis {
+public:
+  /// \brief Inform generic clients of the result type.
+  typedef LazyCallGraph Result;
+
+  static void *ID() { return (void *)&PassID; }
+
+  /// \brief Compute the \c LazyCallGraph for a the module \c M.
+  ///
+  /// This just builds the set of entry points to the call graph. The rest is
+  /// built lazily as it is walked.
+  LazyCallGraph run(Module *M) { return LazyCallGraph(*M); }
+
+private:
+  static char PassID;
+};
+
+/// \brief A pass which prints the call graph to a \c raw_ostream.
+///
+/// This is primarily useful for testing the analysis.
+class LazyCallGraphPrinterPass {
+  raw_ostream &OS;
+
+public:
+  explicit LazyCallGraphPrinterPass(raw_ostream &OS);
+
+  PreservedAnalyses run(Module *M, ModuleAnalysisManager *AM);
+
+  static StringRef name() { return "LazyCallGraphPrinterPass"; }
+};
+
+}
+
+#endif
diff --git a/lib/Analysis/CMakeLists.txt b/lib/Analysis/CMakeLists.txt
index 3624aac450..c6d4573885 100644
--- a/lib/Analysis/CMakeLists.txt
+++ b/lib/Analysis/CMakeLists.txt
@@ -23,6 +23,7 @@ add_llvm_library(LLVMAnalysis
   InstructionSimplify.cpp
   Interval.cpp
   IntervalPartition.cpp
+  LazyCallGraph.cpp
   LazyValueInfo.cpp
   LibCallAliasAnalysis.cpp
   LibCallSemantics.cpp
diff --git a/lib/Analysis/LazyCallGraph.cpp b/lib/Analysis/LazyCallGraph.cpp
new file mode 100644
index 0000000000..b89bf70b43
--- /dev/null
+++ b/lib/Analysis/LazyCallGraph.cpp
@@ -0,0 +1,195 @@
+//===- LazyCallGraph.cpp - Analysis of a Module's call graph --------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/LazyCallGraph.h"
+#include "llvm/ADT/SCCIterator.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/PassManager.h"
+#include "llvm/Support/CallSite.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/InstVisitor.h"
+
+using namespace llvm;
+
+static void findCallees(
+    SmallVectorImpl<Constant *> &Worklist, SmallPtrSetImpl<Constant *> &Visited,
+    SmallVectorImpl<PointerUnion<Function *, LazyCallGraph::Node *> > &Callees,
+    SmallPtrSetImpl<Function *> &CalleeSet) {
+  while (!Worklist.empty()) {
+    Constant *C = Worklist.pop_back_val();
+
+    if (Function *F = dyn_cast<Function>(C)) {
+      // 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.
+      if (!F->isDeclaration() && CalleeSet.insert(F))
+          Callees.push_back(F);
+      continue;
+    }
+
+    for (User::value_op_iterator OI = C->value_op_begin(),
+                                 OE = C->value_op_end();
+         OI != OE; ++OI)
+      if (Visited.insert(cast<Constant>(*OI)))
+        Worklist.push_back(cast<Constant>(*OI));
+  }
+}
+
+LazyCallGraph::Node::Node(LazyCallGraph &G, Function &F) : G(G), F(F) {
+  SmallVector<Constant *, 16> Worklist;
+  SmallPtrSet<Constant *, 16> Visited;
+  // Find all the potential callees in this function. First walk the
+  // instructions and add every operand which is a constant to the worklist.
+  for (Function::iterator BBI = F.begin(), BBE = F.end(); BBI != BBE; ++BBI)
+    for (BasicBlock::iterator II = BBI->begin(), IE = BBI->end(); II != IE;
+         ++II)
+      for (User::value_op_iterator OI = II->value_op_begin(),
+                                   OE = II->value_op_end();
+           OI != OE; ++OI)
+        if (Constant *C = dyn_cast<Constant>(*OI))
+          if (Visited.insert(C))
+            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.
+  findCallees(Worklist, Visited, Callees, CalleeSet);
+}
+
+LazyCallGraph::Node::Node(LazyCallGraph &G, const Node &OtherN)
+    : G(G), F(OtherN.F), CalleeSet(OtherN.CalleeSet) {
+  // Loop over the other node's callees, adding the Function*s to our list
+  // directly, and recursing to add the Node*s.
+  Callees.reserve(OtherN.Callees.size());
+  for (NodeVectorImplT::iterator OI = OtherN.Callees.begin(),
+                                 OE = OtherN.Callees.end();
+       OI != OE; ++OI)
+    if (Function *Callee = OI->dyn_cast<Function *>())
+      Callees.push_back(Callee);
+    else
+      Callees.push_back(G.copyInto(*OI->get<Node *>()));
+}
+
+#if LLVM_HAS_RVALUE_REFERENCES
+LazyCallGraph::Node::Node(LazyCallGraph &G, Node &&OtherN)
+    : G(G), F(OtherN.F), Callees(std::move(OtherN.Callees)),
+      CalleeSet(std::move(OtherN.CalleeSet)) {
+  // Loop over our Callees. They've been moved from another node, but we need
+  // to move the Node*s to live under our bump ptr allocator.
+  for (NodeVectorImplT::iterator CI = Callees.begin(), CE = Callees.end();
+       CI != CE; ++CI)
+    if (Node *ChildN = CI->dyn_cast<Node *>())
+      *CI = G.moveInto(std::move(*ChildN));
+}
+#endif
+
+LazyCallGraph::LazyCallGraph(Module &M) : M(M) {
+  for (Module::iterator FI = M.begin(), FE = M.end(); FI != FE; ++FI)
+    if (!FI->isDeclaration() && !FI->hasLocalLinkage())
+      if (EntryNodeSet.insert(&*FI))
+        EntryNodes.push_back(&*FI);
+
+  // Now add entry nodes for functions reachable via initializers to globals.
+  SmallVector<Constant *, 16> Worklist;
+  SmallPtrSet<Constant *, 16> Visited;
+  for (Module::global_iterator GI = M.global_begin(), GE = M.global_end(); GI != GE; ++GI)
+    if (GI->hasInitializer())
+      if (Visited.insert(GI->getInitializer()))
+        Worklist.push_back(GI->getInitializer());
+
+  findCallees(Worklist, Visited, EntryNodes, EntryNodeSet);
+}
+
+LazyCallGraph::LazyCallGraph(const LazyCallGraph &G)
+    : M(G.M), EntryNodeSet(G.EntryNodeSet) {
+  EntryNodes.reserve(EntryNodes.size());
+  for (NodeVectorImplT::iterator EI = EntryNodes.begin(),
+                                 EE = EntryNodes.end();
+       EI != EE; ++EI)
+    if (Function *Callee = EI->dyn_cast<Function *>())
+      EntryNodes.push_back(Callee);
+    else
+      EntryNodes.push_back(copyInto(*EI->get<Node *>()));
+}
+
+#if LLVM_HAS_RVALUE_REFERENCES
+// FIXME: This would be crazy simpler if BumpPtrAllocator were movable without
+// invalidating any of the allocated memory. We should make that be the case at
+// some point and delete this.
+LazyCallGraph::LazyCallGraph(LazyCallGraph &&G)
+    : M(G.M), EntryNodes(std::move(G.EntryNodes)),
+      EntryNodeSet(std::move(G.EntryNodeSet)) {
+  // Loop over our EntryNodes. They've been moved from another graph, but we
+  // need to move the Node*s to live under our bump ptr allocator.
+  for (NodeVectorImplT::iterator EI = EntryNodes.begin(), EE = EntryNodes.end();
+       EI != EE; ++EI)
+    if (Node *EntryN = EI->dyn_cast<Node *>())
+      *EI = G.moveInto(std::move(*EntryN));
+}
+#endif
+
+LazyCallGraph::Node *LazyCallGraph::insertInto(Function &F, Node *&MappedN) {
+  return new (MappedN = BPA.Allocate()) Node(*this, F);
+}
+
+LazyCallGraph::Node *LazyCallGraph::copyInto(const Node &OtherN) {
+  Node *&N = NodeMap[&OtherN.F];
+  if (N)
+    return N;
+
+  return new (N = BPA.Allocate()) Node(*this, OtherN);
+}
+
+#if LLVM_HAS_RVALUE_REFERENCES
+LazyCallGraph::Node *LazyCallGraph::moveInto(Node &&OtherN) {
+  Node *&N = NodeMap[&OtherN.F];
+  if (N)
+    return N;
+
+  return new (N = BPA.Allocate()) Node(*this, std::move(OtherN));
+}
+#endif
+
+char LazyCallGraphAnalysis::PassID;
+
+LazyCallGraphPrinterPass::LazyCallGraphPrinterPass(raw_ostream &OS) : OS(OS) {}
+
+static void printNodes(raw_ostream &OS, LazyCallGraph::Node &N,
+                       SmallPtrSetImpl<LazyCallGraph::Node *> &Printed) {
+  // Recurse depth first through the nodes.
+  for (LazyCallGraph::iterator I = N.begin(), E = N.end(); I != E; ++I)
+    if (Printed.insert(*I))
+      printNodes(OS, **I, Printed);
+
+  OS << "  Call edges in function: " << N.getFunction().getName() << "\n";
+  for (LazyCallGraph::iterator I = N.begin(), E = N.end(); I != E; ++I)
+    OS << "    -> " << I->getFunction().getName() << "\n";
+
+  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";
+
+  SmallPtrSet<LazyCallGraph::Node *, 16> Printed;
+  for (LazyCallGraph::iterator I = G.begin(), E = G.end(); I != E; ++I)
+    if (Printed.insert(*I))
+      printNodes(OS, **I, Printed);
+
+  return PreservedAnalyses::all();
+}
diff --git a/test/Analysis/LazyCallGraph/basic.ll b/test/Analysis/LazyCallGraph/basic.ll
new file mode 100644
index 0000000000..ebadb75154
--- /dev/null
+++ b/test/Analysis/LazyCallGraph/basic.ll
@@ -0,0 +1,126 @@
+; RUN: opt -disable-output -passes=print-cg %s 2>&1 | FileCheck %s
+;
+; Basic validation of the call graph analysis used in the new pass manager.
+
+define void @f() {
+; CHECK-LABEL: Call edges in function: f
+; CHECK-NOT: ->
+
+entry:
+  ret void
+}
+
+; A bunch more functions just to make it easier to test several call edges at once.
+define void @f1() {
+  ret void
+}
+define void @f2() {
+  ret void
+}
+define void @f3() {
+  ret void
+}
+define void @f4() {
+  ret void
+}
+define void @f5() {
+  ret void
+}
+define void @f6() {
+  ret void
+}
+define void @f7() {
+  ret void
+}
+define void @f8() {
+  ret void
+}
+define void @f9() {
+  ret void
+}
+define void @f10() {
+  ret void
+}
+define void @f11() {
+  ret void
+}
+define void @f12() {
+  ret void
+}
+
+declare i32 @__gxx_personality_v0(...)
+
+define void @test0() {
+; CHECK-LABEL: Call edges in function: test0
+; CHECK-NEXT: -> f
+; CHECK-NOT: ->
+
+entry:
+  call void @f()
+  call void @f()
+  call void @f()
+  call void @f()
+  ret void
+}
+
+define void ()* @test1(void ()** %x) {
+; CHECK-LABEL: Call edges in function: test1
+; CHECK-NEXT: -> f12
+; CHECK-NEXT: -> f11
+; CHECK-NEXT: -> f10
+; CHECK-NEXT: -> f7
+; CHECK-NEXT: -> f9
+; CHECK-NEXT: -> f8
+; CHECK-NEXT: -> f6
+; CHECK-NEXT: -> f5
+; CHECK-NEXT: -> f4
+; CHECK-NEXT: -> f3
+; CHECK-NEXT: -> f2
+; CHECK-NEXT: -> f1
+; CHECK-NOT: ->
+
+entry:
+  br label %next
+
+dead:
+  br label %next
+
+next:
+  phi void ()* [ @f1, %entry ], [ @f2, %dead ]
+  select i1 true, void ()* @f3, void ()* @f4
+  store void ()* @f5, void ()** %x
+  call void @f6()
+  call void (void ()*, void ()*)* bitcast (void ()* @f7 to void (void ()*, void ()*)*)(void ()* @f8, void ()* @f9)
+  invoke void @f10() to label %exit unwind label %unwind
+
+exit:
+  ret void ()* @f11
+
+unwind:
+  %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
+          cleanup
+  resume { i8*, i32 } { i8* bitcast (void ()* @f12 to i8*), i32 42 }
+}
+
+@g = global void ()* @f1
+@g1 = global [4 x void ()*] [void ()* @f2, void ()* @f3, void ()* @f4, void ()* @f5]
+@g2 = global {i8, void ()*, i8} {i8 1, void ()* @f6, i8 2}
+@h = constant void ()* @f7
+
+define void @test2() {
+; CHECK-LABEL: Call edges in function: test2
+; CHECK-NEXT: -> f7
+; CHECK-NEXT: -> f6
+; CHECK-NEXT: -> f5
+; CHECK-NEXT: -> f4
+; CHECK-NEXT: -> f3
+; CHECK-NEXT: -> f2
+; CHECK-NEXT: -> f1
+; CHECK-NOT: ->
+
+  load i8** bitcast (void ()** @g to i8**)
+  load i8** bitcast (void ()** getelementptr ([4 x void ()*]* @g1, i32 0, i32 2) to i8**)
+  load i8** bitcast (void ()** getelementptr ({i8, void ()*, i8}* @g2, i32 0, i32 1) to i8**)
+  load i8** bitcast (void ()** @h to i8**)
+  ret void
+}
diff --git a/tools/opt/NewPMDriver.cpp b/tools/opt/NewPMDriver.cpp
index c25bd73cbc..fc4a1bf76c 100644
--- a/tools/opt/NewPMDriver.cpp
+++ b/tools/opt/NewPMDriver.cpp
@@ -16,6 +16,7 @@
 #include "NewPMDriver.h"
 #include "Passes.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Analysis/LazyCallGraph.h"
 #include "llvm/Bitcode/BitcodeWriterPass.h"
 #include "llvm/IR/IRPrintingPasses.h"
 #include "llvm/IR/LLVMContext.h"
@@ -35,6 +36,10 @@ bool llvm::runPassPipeline(StringRef Arg0, LLVMContext &Context, Module &M,
   FunctionAnalysisManager FAM;
   ModuleAnalysisManager MAM;
 
+  // FIXME: Lift this registration of analysis passes into a .def file adjacent
+  // to the one used to associate names with passes.
+  MAM.registerPass(LazyCallGraphAnalysis());
+
   // Cross register the analysis managers through their proxies.
   MAM.registerPass(FunctionAnalysisManagerModuleProxy(FAM));
   FAM.registerPass(ModuleAnalysisManagerFunctionProxy(MAM));
diff --git a/tools/opt/Passes.cpp b/tools/opt/Passes.cpp
index 36fe6ad126..ca143042f6 100644
--- a/tools/opt/Passes.cpp
+++ b/tools/opt/Passes.cpp
@@ -15,6 +15,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "Passes.h"
+#include "llvm/Analysis/LazyCallGraph.h"
 #include "llvm/IR/IRPrintingPasses.h"
 #include "llvm/IR/PassManager.h"
 #include "llvm/IR/Verifier.h"
@@ -43,6 +44,7 @@ struct NoOpFunctionPass {
 static bool isModulePassName(StringRef Name) {
   if (Name == "no-op-module") return true;
   if (Name == "print") return true;
+  if (Name == "print-cg") return true;
 
   return false;
 }
@@ -63,6 +65,10 @@ static bool parseModulePassName(ModulePassManager &MPM, StringRef Name) {
     MPM.addPass(PrintModulePass(dbgs()));
     return true;
   }
+  if (Name == "print-cg") {
+    MPM.addPass(LazyCallGraphPrinterPass(dbgs()));
+    return true;
+  }
   return false;
 }