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diff --git a/include/llvm/Analysis/PtrUseVisitor.h b/include/llvm/Analysis/PtrUseVisitor.h
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+//===- PtrUseVisitor.h - InstVisitors over a pointers uses ------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file provides a collection of visitors which walk the (instruction)
+/// uses of a pointer. These visitors all provide the same essential behavior
+/// as an InstVisitor with similar template-based flexibility and
+/// implementation strategies.
+///
+/// These can be used, for example, to quickly analyze the uses of an alloca,
+/// global variable, or function argument.
+///
+/// FIXME: Provide a variant which doesn't track offsets and is cheaper.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_PTRUSEVISITOR_H
+#define LLVM_ANALYSIS_PTRUSEVISITOR_H
+
+#include "llvm/ADT/APInt.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/InstVisitor.h"
+#include "llvm/Support/Compiler.h"
+
+namespace llvm {
+
+namespace detail {
+/// \brief Implementation of non-dependent functionality for \c PtrUseVisitor.
+///
+/// See \c PtrUseVisitor for the public interface and detailed comments about
+/// usage. This class is just a helper base class which is not templated and
+/// contains all common code to be shared between different instantiations of
+/// PtrUseVisitor.
+class PtrUseVisitorBase {
+public:
+  /// \brief This class provides information about the result of a visit.
+  ///
+  /// After walking all the users (recursively) of a pointer, the basic
+  /// infrastructure records some commonly useful information such as escape
+  /// analysis and whether the visit completed or aborted early.
+  class PtrInfo {
+  public:
+    PtrInfo() : AbortedInfo(0, false), EscapedInfo(0, false) {}
+
+    /// \brief Reset the pointer info, clearing all state.
+    void reset() {
+      AbortedInfo.setPointer(0);
+      AbortedInfo.setInt(false);
+      EscapedInfo.setPointer(0);
+      EscapedInfo.setInt(false);
+    }
+
+    /// \brief Did we abort the visit early?
+    bool isAborted() const { return AbortedInfo.getInt(); }
+
+    /// \brief Is the pointer escaped at some point?
+    bool isEscaped() const { return EscapedInfo.getInt(); }
+
+    /// \brief Get the instruction causing the visit to abort.
+    /// \returns a pointer to the instruction causing the abort if one is
+    /// available; otherwise returns null.
+    Instruction *getAbortingInst() const { return AbortedInfo.getPointer(); }
+
+    /// \brief Get the instruction causing the pointer to escape.
+    /// \returns a pointer to the instruction which escapes the pointer if one
+    /// is available; otherwise returns null.
+    Instruction *getEscapingInst() const { return EscapedInfo.getPointer(); }
+
+    /// \brief Mark the visit as aborted. Intended for use in a void return.
+    /// \param I The instruction which caused the visit to abort, if available.
+    void setAborted(Instruction *I = 0) {
+      AbortedInfo.setInt(true);
+      AbortedInfo.setPointer(I);
+    }
+
+    /// \brief Mark the pointer as escaped. Intended for use in a void return.
+    /// \param I The instruction which escapes the pointer, if available.
+    void setEscaped(Instruction *I = 0) {
+      EscapedInfo.setInt(true);
+      EscapedInfo.setPointer(I);
+    }
+
+    /// \brief Mark the pointer as escaped, and the visit as aborted. Intended
+    /// for use in a void return.
+    /// \param I The instruction which both escapes the pointer and aborts the
+    /// visit, if available.
+    void setEscapedAndAborted(Instruction *I = 0) {
+      setEscaped(I);
+      setAborted(I);
+    }
+
+  private:
+    PointerIntPair<Instruction *, 1, bool> AbortedInfo, EscapedInfo;
+  };
+
+protected:
+  const DataLayout &DL;
+
+  /// \name Visitation infrastructure
+  /// @{
+
+  /// \brief The info collected about the pointer being visited thus far.
+  PtrInfo PI;
+
+  /// \brief A struct of the data needed to visit a particular use.
+  ///
+  /// This is used to maintain a worklist fo to-visit uses. This is used to
+  /// make the visit be iterative rather than recursive.
+  struct UseToVisit {
+    typedef PointerIntPair<Use *, 1, bool> UseAndIsOffsetKnownPair;
+    UseAndIsOffsetKnownPair UseAndIsOffsetKnown;
+    APInt Offset;
+  };
+
+  /// \brief The worklist of to-visit uses.
+  SmallVector<UseToVisit, 8> Worklist;
+
+  /// \brief A set of visited uses to break cycles in unreachable code.
+  SmallPtrSet<Use *, 8> VisitedUses;
+
+  /// @}
+
+
+  /// \name Per-visit state
+  /// This state is reset for each instruction visited.
+  /// @{
+
+  /// \brief The use currently being visited.
+  Use *U;
+
+  /// \brief True if we have a known constant offset for the use currently
+  /// being visited.
+  bool IsOffsetKnown;
+
+  /// \brief The constant offset of the use if that is known.
+  APInt Offset;
+
+  /// @}
+
+
+  /// Note that the constructor is protected because this class must be a base
+  /// class, we can't create instances directly of this class.
+  PtrUseVisitorBase(const DataLayout &DL) : DL(DL) {}
+
+  /// \brief Enqueue the users of this instruction in the visit worklist.
+  ///
+  /// This will visit the users with the same offset of the current visit
+  /// (including an unknown offset if that is the current state).
+  void enqueueUsers(Instruction &I);
+
+  /// \brief Walk the operands of a GEP and adjust the offset as appropriate.
+  ///
+  /// This routine does the heavy lifting of the pointer walk by computing
+  /// offsets and looking through GEPs.
+  bool adjustOffsetForGEP(GetElementPtrInst &GEPI);
+};
+} // end namespace detail
+
+/// \brief A base class for visitors over the uses of a pointer value.
+///
+/// Once constructed, a user can call \c visit on a pointer value, and this
+/// will walk its uses and visit each instruction using an InstVisitor. It also
+/// provides visit methods which will recurse through any pointer-to-pointer
+/// transformations such as GEPs and bitcasts.
+///
+/// During the visit, the current Use* being visited is available to the
+/// subclass, as well as the current offset from the original base pointer if
+/// known.
+///
+/// The recursive visit of uses is accomplished with a worklist, so the only
+/// ordering guarantee is that an instruction is visited before any uses of it
+/// are visited. Note that this does *not* mean before any of its users are
+/// visited! This is because users can be visited multiple times due to
+/// multiple, different uses of pointers derived from the same base.
+///
+/// A particular Use will only be visited once, but a User may be visited
+/// multiple times, once per Use. This visits may notably have different
+/// offsets.
+///
+/// All visit methods on the underlying InstVisitor return a boolean. This
+/// return short-circuits the visit, stopping it immediately.
+///
+/// FIXME: Generalize this for all values rather than just instructions.
+template <typename DerivedT>
+class PtrUseVisitor : protected InstVisitor<DerivedT>,
+                      public detail::PtrUseVisitorBase {
+  friend class InstVisitor<DerivedT>;
+  typedef InstVisitor<DerivedT> Base;
+
+public:
+  PtrUseVisitor(const DataLayout &DL) : PtrUseVisitorBase(DL) {}
+
+  /// \brief Recursively visit the uses of the given pointer.
+  /// \returns An info struct about the pointer. See \c PtrInfo for details.
+  PtrInfo visitPtr(Instruction &I) {
+    // This must be a pointer type. Get an integer type suitable to hold
+    // offsets on this pointer.
+    // FIXME: Support a vector of pointers.
+    assert(I.getType()->isPointerTy());
+    IntegerType *IntPtrTy = cast<IntegerType>(DL.getIntPtrType(I.getType()));
+    IsOffsetKnown = true;
+    Offset = APInt(IntPtrTy->getBitWidth(), 0);
+    PI.reset();
+
+    // Enqueue the uses of this pointer.
+    enqueueUsers(I);
+
+    // Visit all the uses off the worklist until it is empty.
+    while (!Worklist.empty()) {
+      UseToVisit ToVisit = Worklist.pop_back_val();
+      U = ToVisit.UseAndIsOffsetKnown.getPointer();
+      IsOffsetKnown = ToVisit.UseAndIsOffsetKnown.getInt();
+      if (IsOffsetKnown)
+        Offset = llvm_move(ToVisit.Offset);
+
+      Instruction *I = cast<Instruction>(U->getUser());
+      static_cast<DerivedT*>(this)->visit(I);
+      if (PI.isAborted())
+        break;
+    }
+    return PI;
+  }
+
+protected:
+  void visitStoreInst(StoreInst &SI) {
+    if (SI.getValueOperand() == U->get())
+      PI.setEscaped(&SI);
+  }
+
+  void visitBitCastInst(BitCastInst &BC) {
+    enqueueUsers(BC);
+  }
+
+  void visitPtrToIntInst(PtrToIntInst &I) {
+    PI.setEscaped(&I);
+  }
+
+  void visitGetElementPtrInst(GetElementPtrInst &GEPI) {
+    if (GEPI.use_empty())
+      return;
+
+    // If we can't walk the GEP, clear the offset.
+    if (!adjustOffsetForGEP(GEPI)) {
+      IsOffsetKnown = false;
+      Offset = APInt();
+    }
+
+    // Enqueue the users now that the offset has been adjusted.
+    enqueueUsers(GEPI);
+  }
+
+  // No-op intrinsics which we know don't escape the pointer to to logic in
+  // some other function.
+  void visitDbgInfoIntrinsic(DbgInfoIntrinsic &I) {}
+  void visitMemIntrinsic(MemIntrinsic &I) {}
+  void visitIntrinsicInst(IntrinsicInst &II) {
+    switch (II.getIntrinsicID()) {
+    default:
+      return Base::visitIntrinsicInst(II);
+
+    case Intrinsic::lifetime_start:
+    case Intrinsic::lifetime_end:
+      return; // No-op intrinsics.
+    }
+  }
+
+  // Generically, arguments to calls and invokes escape the pointer to some
+  // other function. Mark that.
+  void visitCallSite(CallSite CS) {
+    PI.setEscaped(CS.getInstruction());
+    Base::visitCallSite(CS);
+  }
+};
+
+}
+
+#endif