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diff --git a/lib/ExecutionEngine/Interpreter/Interpreter.cpp b/lib/ExecutionEngine/Interpreter/Interpreter.cpp
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index 0000000000..2dba4d694b
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+++ b/lib/ExecutionEngine/Interpreter/Interpreter.cpp
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+//===- Interpreter.cpp - Top-Level LLVM Interpreter Implementation --------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the top-level functionality for the LLVM interpreter.
+// This interpreter is designed to be a very simple, portable, inefficient
+// interpreter.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Interpreter.h"
+#include "llvm/CodeGen/IntrinsicLowering.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Module.h"
+using namespace llvm;
+
+/// create - Create a new interpreter object.  This can never fail.
+///
+ExecutionEngine *Interpreter::create(Module *M, IntrinsicLowering *IL) {
+  bool isLittleEndian = false;
+  switch (M->getEndianness()) {
+  case Module::LittleEndian: isLittleEndian = true; break;
+  case Module::BigEndian:    isLittleEndian = false; break;
+  case Module::AnyPointerSize:
+    int Test = 0;
+    *(char*)&Test = 1;    // Return true if the host is little endian
+    isLittleEndian = (Test == 1);
+    break;
+  }
+
+  bool isLongPointer = false;
+  switch (M->getPointerSize()) {
+  case Module::Pointer32: isLongPointer = false; break;
+  case Module::Pointer64: isLongPointer = true; break;
+  case Module::AnyPointerSize:
+    isLongPointer = (sizeof(void*) == 8);  // Follow host
+    break;
+  }
+
+  return new Interpreter(M, isLittleEndian, isLongPointer, IL);
+}
+
+//===----------------------------------------------------------------------===//
+// Interpreter ctor - Initialize stuff
+//
+Interpreter::Interpreter(Module *M, bool isLittleEndian, bool isLongPointer,
+                         IntrinsicLowering *il)
+  : ExecutionEngine(M), ExitCode(0),
+    TD("lli", isLittleEndian, isLongPointer ? 8 : 4, isLongPointer ? 8 : 4,
+       isLongPointer ? 8 : 4), IL(il) {
+
+  setTargetData(TD);
+  // Initialize the "backend"
+  initializeExecutionEngine();
+  initializeExternalFunctions();
+  emitGlobals();
+
+  if (IL == 0) IL = new DefaultIntrinsicLowering();
+}
+
+Interpreter::~Interpreter() {
+  delete IL;
+}
+
+void Interpreter::runAtExitHandlers () {
+  while (!AtExitHandlers.empty()) {
+    callFunction(AtExitHandlers.back(), std::vector<GenericValue>());
+    AtExitHandlers.pop_back();
+    run();
+  }
+}
+
+/// run - Start execution with the specified function and arguments.
+///
+GenericValue
+Interpreter::runFunction(Function *F,
+                         const std::vector<GenericValue> &ArgValues) {
+  assert (F && "Function *F was null at entry to run()");
+
+  // Try extra hard not to pass extra args to a function that isn't
+  // expecting them.  C programmers frequently bend the rules and
+  // declare main() with fewer parameters than it actually gets
+  // passed, and the interpreter barfs if you pass a function more
+  // parameters than it is declared to take. This does not attempt to
+  // take into account gratuitous differences in declared types,
+  // though.
+  std::vector<GenericValue> ActualArgs;
+  const unsigned ArgCount = F->getFunctionType()->getNumParams();
+  for (unsigned i = 0; i < ArgCount; ++i)
+    ActualArgs.push_back(ArgValues[i]);
+
+  // Set up the function call.
+  callFunction(F, ActualArgs);
+
+  // Start executing the function.
+  run();
+
+  GenericValue rv;
+  rv.IntVal = ExitCode;
+  return rv;
+}
+