[Kaleidoscope] Remove the old Kaleidoscope/ORC tutorial series.

This code has been superseded by the new Building A JIT series.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271059 91177308-0d34-0410-b5e6-96231b3b80d8

13 files changed, 0 insertions, 5684 deletions

diff --git a/examples/Kaleidoscope/Orc/CMakeLists.txt b/examples/Kaleidoscope/Orc/CMakeLists.txt
deleted file mode 100644
index 5aa04543dc6..00000000000
--- a/examples/Kaleidoscope/Orc/CMakeLists.txt
+++ /dev/null
@@ -1,4 +0,0 @@
-add_subdirectory(initial)
-add_subdirectory(lazy_codegen)
-add_subdirectory(lazy_irgen)
-add_subdirectory(fully_lazy)
diff --git a/examples/Kaleidoscope/Orc/fully_lazy/CMakeLists.txt b/examples/Kaleidoscope/Orc/fully_lazy/CMakeLists.txt
deleted file mode 100644
index abb0428a152..00000000000
--- a/examples/Kaleidoscope/Orc/fully_lazy/CMakeLists.txt
+++ /dev/null
@@ -1,13 +0,0 @@
-set(LLVM_LINK_COMPONENTS
-  Core
-  ExecutionEngine
-  Object
-  OrcJIT
-  RuntimeDyld
-  Support
-  native
-  )
-
-add_kaleidoscope_chapter(Kaleidoscope-Orc-fully_lazy
-  toy.cpp
-  )
diff --git a/examples/Kaleidoscope/Orc/fully_lazy/README.txt b/examples/Kaleidoscope/Orc/fully_lazy/README.txt
deleted file mode 100644
index c0189319f2c..00000000000
--- a/examples/Kaleidoscope/Orc/fully_lazy/README.txt
+++ /dev/null
@@ -1,21 +0,0 @@
-//===----------------------------------------------------------------------===/
-//                 Kaleidoscope with Orc - Lazy IRGen Version
-//===----------------------------------------------------------------------===//
-
-This version of Kaleidoscope with Orc demonstrates fully lazy IR-generation.
-Building on the lazy-irgen version of the tutorial, this version injects JIT
-callbacks to defer the bulk of IR-generation and code-generation of functions until
-they are first called.
-
-When a function definition is entered, a JIT callback is created and a stub
-function is built that will call the body of the function indirectly. The body of
-the function is *not* IRGen'd at this point. Instead, the function pointer for
-the indirect call is initialized to point at the JIT callback, and the compile
-action for the callback is initialized with a lambda that IRGens the body of the
-function and adds it to the JIT. The function pointer is updated by the JIT
-callback's update action to point at the newly emitted function body, so future
-calls to the stub will go straight to the body, not through the JIT.
-
-This directory contains a Makefile that allows the code to be built in a
-standalone manner, independent of the larger LLVM build infrastructure. To build
-the program you will need to have 'clang++' and 'llvm-config' in your path.
diff --git a/examples/Kaleidoscope/Orc/fully_lazy/toy.cpp b/examples/Kaleidoscope/Orc/fully_lazy/toy.cpp
deleted file mode 100644
index 705e485eab6..00000000000
--- a/examples/Kaleidoscope/Orc/fully_lazy/toy.cpp
+++ /dev/null
@@ -1,1461 +0,0 @@
-#include "llvm/ADT/APFloat.h"
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ExecutionEngine/ExecutionEngine.h"
-#include "llvm/ExecutionEngine/RuntimeDyld.h"
-#include "llvm/ExecutionEngine/SectionMemoryManager.h"
-#include "llvm/ExecutionEngine/Orc/CompileUtils.h"
-#include "llvm/ExecutionEngine/Orc/IndirectionUtils.h"
-#include "llvm/ExecutionEngine/Orc/IRCompileLayer.h"
-#include "llvm/ExecutionEngine/Orc/JITSymbol.h"
-#include "llvm/ExecutionEngine/Orc/LambdaResolver.h"
-#include "llvm/ExecutionEngine/Orc/LazyEmittingLayer.h"
-#include "llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h"
-#include "llvm/ExecutionEngine/Orc/OrcABISupport.h"
-#include "llvm/IR/BasicBlock.h"
-#include "llvm/IR/Constant.h"
-#include "llvm/IR/Constants.h"
-#include "llvm/IR/DerivedTypes.h"
-#include "llvm/IR/Function.h"
-#include "llvm/IR/GlobalVariable.h"
-#include "llvm/IR/Instructions.h"
-#include "llvm/IR/IRBuilder.h"
-#include "llvm/IR/LLVMContext.h"
-#include "llvm/IR/Mangler.h"
-#include "llvm/IR/Module.h"
-#include "llvm/IR/Type.h"
-#include "llvm/IR/Verifier.h"
-#include "llvm/Support/raw_ostream.h"
-#include "llvm/Support/TargetSelect.h"
-#include "llvm/Target/TargetMachine.h"
-#include <cassert>
-#include <cctype>
-#include <cstdint>
-#include <cstdio>
-#include <cstdlib>
-#include <iomanip>
-#include <iostream>
-#include <map>
-#include <memory>
-#include <sstream>
-#include <string>
-#include <utility>
-#include <vector>
-
-using namespace llvm;
-using namespace llvm::orc;
-
-//===----------------------------------------------------------------------===//
-// Lexer
-//===----------------------------------------------------------------------===//
-
-// The lexer returns tokens [0-255] if it is an unknown character, otherwise one
-// of these for known things.
-enum Token {
-  tok_eof = -1,
-
-  // commands
-  tok_def = -2, tok_extern = -3,
-
-  // primary
-  tok_identifier = -4, tok_number = -5,
-
-  // control
-  tok_if = -6, tok_then = -7, tok_else = -8,
-  tok_for = -9, tok_in = -10,
-
-  // operators
-  tok_binary = -11, tok_unary = -12,
-
-  // var definition
-  tok_var = -13
-};
-
-static std::string IdentifierStr;  // Filled in if tok_identifier
-static double NumVal;              // Filled in if tok_number
-
-/// gettok - Return the next token from standard input.
-static int gettok() {
-  static int LastChar = ' ';
-
-  // Skip any whitespace.
-  while (isspace(LastChar))
-    LastChar = getchar();
-
-  if (isalpha(LastChar)) { // identifier: [a-zA-Z][a-zA-Z0-9]*
-    IdentifierStr = LastChar;
-    while (isalnum((LastChar = getchar())))
-      IdentifierStr += LastChar;
-
-    if (IdentifierStr == "def") return tok_def;
-    if (IdentifierStr == "extern") return tok_extern;
-    if (IdentifierStr == "if") return tok_if;
-    if (IdentifierStr == "then") return tok_then;
-    if (IdentifierStr == "else") return tok_else;
-    if (IdentifierStr == "for") return tok_for;
-    if (IdentifierStr == "in") return tok_in;
-    if (IdentifierStr == "binary") return tok_binary;
-    if (IdentifierStr == "unary") return tok_unary;
-    if (IdentifierStr == "var") return tok_var;
-    return tok_identifier;
-  }
-
-  if (isdigit(LastChar) || LastChar == '.') {   // Number: [0-9.]+
-    std::string NumStr;
-    do {
-      NumStr += LastChar;
-      LastChar = getchar();
-    } while (isdigit(LastChar) || LastChar == '.');
-
-    NumVal = strtod(NumStr.c_str(), nullptr);
-    return tok_number;
-  }
-
-  if (LastChar == '#') {
-    // Comment until end of line.
-    do LastChar = getchar();
-    while (LastChar != EOF && LastChar != '\n' && LastChar != '\r');
-
-    if (LastChar != EOF)
-      return gettok();
-  }
-
-  // Check for end of file.  Don't eat the EOF.
-  if (LastChar == EOF)
-    return tok_eof;
-
-  // Otherwise, just return the character as its ascii value.
-  int ThisChar = LastChar;
-  LastChar = getchar();
-  return ThisChar;
-}
-
-//===----------------------------------------------------------------------===//
-// Abstract Syntax Tree (aka Parse Tree)
-//===----------------------------------------------------------------------===//
-
-class IRGenContext;
-
-/// ExprAST - Base class for all expression nodes.
-struct ExprAST {
-  virtual ~ExprAST() {}
-  virtual Value *IRGen(IRGenContext &C) const = 0;
-};
-
-/// NumberExprAST - Expression class for numeric literals like "1.0".
-struct NumberExprAST : public ExprAST {
-  NumberExprAST(double Val) : Val(Val) {}
-  Value *IRGen(IRGenContext &C) const override;
-
-  double Val;
-};
-
-/// VariableExprAST - Expression class for referencing a variable, like "a".
-struct VariableExprAST : public ExprAST {
-  VariableExprAST(std::string Name) : Name(std::move(Name)) {}
-  Value *IRGen(IRGenContext &C) const override;
-
-  std::string Name;
-};
-
-/// UnaryExprAST - Expression class for a unary operator.
-struct UnaryExprAST : public ExprAST {
-  UnaryExprAST(char Opcode, std::unique_ptr<ExprAST> Operand)
-    : Opcode(std::move(Opcode)), Operand(std::move(Operand)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  char Opcode;
-  std::unique_ptr<ExprAST> Operand;
-};
-
-/// BinaryExprAST - Expression class for a binary operator.
-struct BinaryExprAST : public ExprAST {
-  BinaryExprAST(char Op, std::unique_ptr<ExprAST> LHS,
-                std::unique_ptr<ExprAST> RHS)
-    : Op(Op), LHS(std::move(LHS)), RHS(std::move(RHS)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  char Op;
-  std::unique_ptr<ExprAST> LHS, RHS;
-};
-
-/// CallExprAST - Expression class for function calls.
-struct CallExprAST : public ExprAST {
-  CallExprAST(std::string CalleeName,
-              std::vector<std::unique_ptr<ExprAST>> Args)
-    : CalleeName(std::move(CalleeName)), Args(std::move(Args)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  std::string CalleeName;
-  std::vector<std::unique_ptr<ExprAST>> Args;
-};
-
-/// IfExprAST - Expression class for if/then/else.
-struct IfExprAST : public ExprAST {
-  IfExprAST(std::unique_ptr<ExprAST> Cond, std::unique_ptr<ExprAST> Then,
-            std::unique_ptr<ExprAST> Else)
-    : Cond(std::move(Cond)), Then(std::move(Then)), Else(std::move(Else)) {}
-  Value *IRGen(IRGenContext &C) const override;
-
-  std::unique_ptr<ExprAST> Cond, Then, Else;
-};
-
-/// ForExprAST - Expression class for for/in.
-struct ForExprAST : public ExprAST {
-  ForExprAST(std::string VarName, std::unique_ptr<ExprAST> Start,
-             std::unique_ptr<ExprAST> End, std::unique_ptr<ExprAST> Step,
-             std::unique_ptr<ExprAST> Body)
-    : VarName(std::move(VarName)), Start(std::move(Start)), End(std::move(End)),
-      Step(std::move(Step)), Body(std::move(Body)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  std::string VarName;
-  std::unique_ptr<ExprAST> Start, End, Step, Body;
-};
-
-/// VarExprAST - Expression class for var/in
-struct VarExprAST : public ExprAST {
-  typedef std::pair<std::string, std::unique_ptr<ExprAST>> Binding;
-  typedef std::vector<Binding> BindingList;
-
-  VarExprAST(BindingList VarBindings, std::unique_ptr<ExprAST> Body)
-    : VarBindings(std::move(VarBindings)), Body(std::move(Body)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  BindingList VarBindings;
-  std::unique_ptr<ExprAST> Body;
-};
-
-/// PrototypeAST - This class represents the "prototype" for a function,
-/// which captures its argument names as well as if it is an operator.
-struct PrototypeAST {
-  PrototypeAST(std::string Name, std::vector<std::string> Args,
-               bool IsOperator = false, unsigned Precedence = 0)
-    : Name(std::move(Name)), Args(std::move(Args)), IsOperator(IsOperator),
-      Precedence(Precedence) {}
-
-  Function *IRGen(IRGenContext &C) const;
-  void CreateArgumentAllocas(Function *F, IRGenContext &C);
-
-  bool isUnaryOp() const { return IsOperator && Args.size() == 1; }
-  bool isBinaryOp() const { return IsOperator && Args.size() == 2; }
-
-  char getOperatorName() const {
-    assert(isUnaryOp() || isBinaryOp());
-    return Name[Name.size()-1];
-  }
-
-  std::string Name;
-  std::vector<std::string> Args;
-  bool IsOperator;
-  unsigned Precedence;  // Precedence if a binary op.
-};
-
-/// FunctionAST - This class represents a function definition itself.
-struct FunctionAST {
-  FunctionAST(std::unique_ptr<PrototypeAST> Proto,
-              std::unique_ptr<ExprAST> Body)
-    : Proto(std::move(Proto)), Body(std::move(Body)) {}
-
-  Function *IRGen(IRGenContext &C) const;
-
-  std::unique_ptr<PrototypeAST> Proto;
-  std::unique_ptr<ExprAST> Body;
-};
-
-//===----------------------------------------------------------------------===//
-// Parser
-//===----------------------------------------------------------------------===//
-
-/// CurTok/getNextToken - Provide a simple token buffer.  CurTok is the current
-/// token the parser is looking at.  getNextToken reads another token from the
-/// lexer and updates CurTok with its results.
-static int CurTok;
-static int getNextToken() {
-  return CurTok = gettok();
-}
-
-/// BinopPrecedence - This holds the precedence for each binary operator that is
-/// defined.
-static std::map<char, int> BinopPrecedence;
-
-/// GetTokPrecedence - Get the precedence of the pending binary operator token.
-static int GetTokPrecedence() {
-  if (!isascii(CurTok))
-    return -1;
-
-  // Make sure it's a declared binop.
-  int TokPrec = BinopPrecedence[CurTok];
-  if (TokPrec <= 0) return -1;
-  return TokPrec;
-}
-
-template <typename T>
-std::unique_ptr<T> ErrorU(const std::string &Str) {
-  std::cerr << "Error: " << Str << "\n";
-  return nullptr;
-}
-
-template <typename T>
-T* ErrorP(const std::string &Str) {
-  std::cerr << "Error: " << Str << "\n";
-  return nullptr;
-}
-
-static std::unique_ptr<ExprAST> ParseExpression();
-
-/// identifierexpr
-///   ::= identifier
-///   ::= identifier '(' expression* ')'
-static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
-  std::string IdName = IdentifierStr;
-
-  getNextToken();  // eat identifier.
-
-  if (CurTok != '(') // Simple variable ref.
-    return llvm::make_unique<VariableExprAST>(IdName);
-
-  // Call.
-  getNextToken();  // eat (
-  std::vector<std::unique_ptr<ExprAST>> Args;
-  if (CurTok != ')') {
-    while (true) {
-      auto Arg = ParseExpression();
-      if (!Arg) return nullptr;
-      Args.push_back(std::move(Arg));
-
-      if (CurTok == ')') break;
-
-      if (CurTok != ',')
-        return ErrorU<CallExprAST>("Expected ')' or ',' in argument list");
-      getNextToken();
-    }
-  }
-
-  // Eat the ')'.
-  getNextToken();
-
-  return llvm::make_unique<CallExprAST>(IdName, std::move(Args));
-}
-
-/// numberexpr ::= number
-static std::unique_ptr<NumberExprAST> ParseNumberExpr() {
-  auto Result = llvm::make_unique<NumberExprAST>(NumVal);
-  getNextToken(); // consume the number
-  return Result;
-}
-
-/// parenexpr ::= '(' expression ')'
-static std::unique_ptr<ExprAST> ParseParenExpr() {
-  getNextToken();  // eat (.
-  auto V = ParseExpression();
-  if (!V)
-    return nullptr;
-
-  if (CurTok != ')')
-    return ErrorU<ExprAST>("expected ')'");
-  getNextToken();  // eat ).
-  return V;
-}
-
-/// ifexpr ::= 'if' expression 'then' expression 'else' expression
-static std::unique_ptr<ExprAST> ParseIfExpr() {
-  getNextToken();  // eat the if.
-
-  // condition.
-  auto Cond = ParseExpression();
-  if (!Cond)
-    return nullptr;
-
-  if (CurTok != tok_then)
-    return ErrorU<ExprAST>("expected then");
-  getNextToken();  // eat the then
-
-  auto Then = ParseExpression();
-  if (!Then)
-    return nullptr;
-
-  if (CurTok != tok_else)
-    return ErrorU<ExprAST>("expected else");
-
-  getNextToken();
-
-  auto Else = ParseExpression();
-  if (!Else)
-    return nullptr;
-
-  return llvm::make_unique<IfExprAST>(std::move(Cond), std::move(Then),
-                                      std::move(Else));
-}
-
-/// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression
-static std::unique_ptr<ForExprAST> ParseForExpr() {
-  getNextToken();  // eat the for.
-
-  if (CurTok != tok_identifier)
-    return ErrorU<ForExprAST>("expected identifier after for");
-
-  std::string IdName = IdentifierStr;
-  getNextToken();  // eat identifier.
-
-  if (CurTok != '=')
-    return ErrorU<ForExprAST>("expected '=' after for");
-  getNextToken();  // eat '='.
-
-  auto Start = ParseExpression();
-  if (!Start)
-    return nullptr;
-  if (CurTok != ',')
-    return ErrorU<ForExprAST>("expected ',' after for start value");
-  getNextToken();
-
-  auto End = ParseExpression();
-  if (!End)
-    return nullptr;
-
-  // The step value is optional.
-  std::unique_ptr<ExprAST> Step;
-  if (CurTok == ',') {
-    getNextToken();
-    Step = ParseExpression();
-    if (!Step)
-      return nullptr;
-  }
-
-  if (CurTok != tok_in)
-    return ErrorU<ForExprAST>("expected 'in' after for");
-  getNextToken();  // eat 'in'.
-
-  auto Body = ParseExpression();
-  if (Body)
-    return nullptr;
-
-  return llvm::make_unique<ForExprAST>(IdName, std::move(Start), std::move(End),
-                                       std::move(Step), std::move(Body));
-}
-
-/// varexpr ::= 'var' identifier ('=' expression)?
-//                    (',' identifier ('=' expression)?)* 'in' expression
-static std::unique_ptr<VarExprAST> ParseVarExpr() {
-  getNextToken();  // eat the var.
-
-  VarExprAST::BindingList VarBindings;
-
-  // At least one variable name is required.
-  if (CurTok != tok_identifier)
-    return ErrorU<VarExprAST>("expected identifier after var");
-
-  while (true) {
-    std::string Name = IdentifierStr;
-    getNextToken();  // eat identifier.
-
-    // Read the optional initializer.
-    std::unique_ptr<ExprAST> Init;
-    if (CurTok == '=') {
-      getNextToken(); // eat the '='.
-
-      Init = ParseExpression();
-      if (!Init)
-        return nullptr;
-    }
-
-    VarBindings.push_back(VarExprAST::Binding(Name, std::move(Init)));
-
-    // End of var list, exit loop.
-    if (CurTok != ',') break;
-    getNextToken(); // eat the ','.
-
-    if (CurTok != tok_identifier)
-      return ErrorU<VarExprAST>("expected identifier list after var");
-  }
-
-  // At this point, we have to have 'in'.
-  if (CurTok != tok_in)
-    return ErrorU<VarExprAST>("expected 'in' keyword after 'var'");
-  getNextToken();  // eat 'in'.
-
-  auto Body = ParseExpression();
-  if (!Body)
-    return nullptr;
-
-  return llvm::make_unique<VarExprAST>(std::move(VarBindings), std::move(Body));
-}
-
-/// primary
-///   ::= identifierexpr
-///   ::= numberexpr
-///   ::= parenexpr
-///   ::= ifexpr
-///   ::= forexpr
-///   ::= varexpr
-static std::unique_ptr<ExprAST> ParsePrimary() {
-  switch (CurTok) {
-  default: return ErrorU<ExprAST>("unknown token when expecting an expression");
-  case tok_identifier: return ParseIdentifierExpr();
-  case tok_number:     return ParseNumberExpr();
-  case '(':            return ParseParenExpr();
-  case tok_if:         return ParseIfExpr();
-  case tok_for:        return ParseForExpr();
-  case tok_var:        return ParseVarExpr();
-  }
-}
-
-/// unary
-///   ::= primary
-///   ::= '!' unary
-static std::unique_ptr<ExprAST> ParseUnary() {
-  // If the current token is not an operator, it must be a primary expr.
-  if (!isascii(CurTok) || CurTok == '(' || CurTok == ',')
-    return ParsePrimary();
-
-  // If this is a unary operator, read it.
-  int Opc = CurTok;
-  getNextToken();
-  if (auto Operand = ParseUnary())
-    return llvm::make_unique<UnaryExprAST>(Opc, std::move(Operand));
-  return nullptr;
-}
-
-/// binoprhs
-///   ::= ('+' unary)*
-static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec,
-                                              std::unique_ptr<ExprAST> LHS) {
-  // If this is a binop, find its precedence.
-  while (true) {
-    int TokPrec = GetTokPrecedence();
-
-    // If this is a binop that binds at least as tightly as the current binop,
-    // consume it, otherwise we are done.
-    if (TokPrec < ExprPrec)
-      return LHS;
-
-    // Okay, we know this is a binop.
-    int BinOp = CurTok;
-    getNextToken();  // eat binop
-
-    // Parse the unary expression after the binary operator.
-    auto RHS = ParseUnary();
-    if (!RHS)
-      return nullptr;
-
-    // If BinOp binds less tightly with RHS than the operator after RHS, let
-    // the pending operator take RHS as its LHS.
-    int NextPrec = GetTokPrecedence();
-    if (TokPrec < NextPrec) {
-      RHS = ParseBinOpRHS(TokPrec+1, std::move(RHS));
-      if (!RHS)
-        return nullptr;
-    }
-
-    // Merge LHS/RHS.
-    LHS = llvm::make_unique<BinaryExprAST>(BinOp, std::move(LHS), std::move(RHS));
-  }
-}
-
-/// expression
-///   ::= unary binoprhs
-///
-static std::unique_ptr<ExprAST> ParseExpression() {
-  auto LHS = ParseUnary();
-  if (!LHS)
-    return nullptr;
-
-  return ParseBinOpRHS(0, std::move(LHS));
-}
-
-/// prototype
-///   ::= id '(' id* ')'
-///   ::= binary LETTER number? (id, id)
-///   ::= unary LETTER (id)
-static std::unique_ptr<PrototypeAST> ParsePrototype() {
-  std::string FnName;
-
-  unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.
-  unsigned BinaryPrecedence = 30;
-
-  switch (CurTok) {
-  default:
-    return ErrorU<PrototypeAST>("Expected function name in prototype");
-  case tok_identifier:
-    FnName = IdentifierStr;
-    Kind = 0;
-    getNextToken();
-    break;
-  case tok_unary:
-    getNextToken();
-    if (!isascii(CurTok))
-      return ErrorU<PrototypeAST>("Expected unary operator");
-    FnName = "unary";
-    FnName += (char)CurTok;
-    Kind = 1;
-    getNextToken();
-    break;
-  case tok_binary:
-    getNextToken();
-    if (!isascii(CurTok))
-      return ErrorU<PrototypeAST>("Expected binary operator");
-    FnName = "binary";
-    FnName += (char)CurTok;
-    Kind = 2;
-    getNextToken();
-
-    // Read the precedence if present.
-    if (CurTok == tok_number) {
-      if (NumVal < 1 || NumVal > 100)
-        return ErrorU<PrototypeAST>("Invalid precedecnce: must be 1..100");
-      BinaryPrecedence = (unsigned)NumVal;
-      getNextToken();
-    }
-    break;
-  }
-
-  if (CurTok != '(')
-    return ErrorU<PrototypeAST>("Expected '(' in prototype");
-
-  std::vector<std::string> ArgNames;
-  while (getNextToken() == tok_identifier)
-    ArgNames.push_back(IdentifierStr);
-  if (CurTok != ')')
-    return ErrorU<PrototypeAST>("Expected ')' in prototype");
-
-  // success.
-  getNextToken();  // eat ')'.
-
-  // Verify right number of names for operator.
-  if (Kind && ArgNames.size() != Kind)
-    return ErrorU<PrototypeAST>("Invalid number of operands for operator");
-
-  return llvm::make_unique<PrototypeAST>(FnName, std::move(ArgNames), Kind != 0,
-                                         BinaryPrecedence);
-}
-
-/// definition ::= 'def' prototype expression
-static std::unique_ptr<FunctionAST> ParseDefinition() {
-  getNextToken();  // eat def.
-  auto Proto = ParsePrototype();
-  if (!Proto)
-    return nullptr;
-
-  if (auto Body = ParseExpression())
-    return llvm::make_unique<FunctionAST>(std::move(Proto), std::move(Body));
-  return nullptr;
-}
-
-/// toplevelexpr ::= expression
-static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
-  if (auto E = ParseExpression()) {
-    // Make an anonymous proto.
-    auto Proto =
-      llvm::make_unique<PrototypeAST>("__anon_expr", std::vector<std::string>());
-    return llvm::make_unique<FunctionAST>(std::move(Proto), std::move(E));
-  }
-  return nullptr;
-}
-
-/// external ::= 'extern' prototype
-static std::unique_ptr<PrototypeAST> ParseExtern() {
-  getNextToken();  // eat extern.
-  return ParsePrototype();
-}
-
-//===----------------------------------------------------------------------===//
-// Code Generation
-//===----------------------------------------------------------------------===//
-
-// FIXME: Obviously we can do better than this
-std::string GenerateUniqueName(const std::string &Root) {
-  static int i = 0;
-  std::ostringstream NameStream;
-  NameStream << Root << ++i;
-  return NameStream.str();
-}
-
-std::string MakeLegalFunctionName(std::string Name)
-{
-  std::string NewName;
-  assert(!Name.empty() && "Base name must not be empty");
-
-  // Start with what we have
-  NewName = Name;
-
-  // Look for a numberic first character
-  if (NewName.find_first_of("0123456789") == 0) {
-    NewName.insert(0, 1, 'n');
-  }
-
-  // Replace illegal characters with their ASCII equivalent
-  std::string legal_elements = "_abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
-  size_t pos;
-  while ((pos = NewName.find_first_not_of(legal_elements)) != std::string::npos) {
-    std::ostringstream NumStream;
-    NumStream << (int)NewName.at(pos);
-    NewName = NewName.replace(pos, 1, NumStream.str());
-  }
-
-  return NewName;
-}
-
-class SessionContext {
-public:
-  SessionContext(LLVMContext &C)
-    : Context(C), TM(EngineBuilder().selectTarget()) {}
-  LLVMContext& getLLVMContext() const { return Context; }
-  TargetMachine& getTarget() { return *TM; }
-  void addPrototypeAST(std::unique_ptr<PrototypeAST> P);
-  PrototypeAST* getPrototypeAST(const std::string &Name);
-
-private:
-  typedef std::map<std::string, std::unique_ptr<PrototypeAST>> PrototypeMap;
-
-  LLVMContext &Context;
-  std::unique_ptr<TargetMachine> TM;
-
-  PrototypeMap Prototypes;
-};
-
-void SessionContext::addPrototypeAST(std::unique_ptr<PrototypeAST> P) {
-  Prototypes[P->Name] = std::move(P);
-}
-
-PrototypeAST* SessionContext::getPrototypeAST(const std::string &Name) {
-  PrototypeMap::iterator I = Prototypes.find(Name);
-  if (I != Prototypes.end())
-    return I->second.get();
-  return nullptr;
-}
-
-class IRGenContext {
-public:
-  IRGenContext(SessionContext &S)
-    : Session(S),
-      M(new Module(GenerateUniqueName("jit_module_"),
-                   Session.getLLVMContext())),
-      Builder(Session.getLLVMContext()) {
-    M->setDataLayout(Session.getTarget().createDataLayout());
-  }
-
-  SessionContext& getSession() { return Session; }
-  Module& getM() const { return *M; }
-  std::unique_ptr<Module> takeM() { return std::move(M); }
-  IRBuilder<>& getBuilder() { return Builder; }
-  LLVMContext& getLLVMContext() { return Session.getLLVMContext(); }
-  Function* getPrototype(const std::string &Name);
-
-  std::map<std::string, AllocaInst*> NamedValues;
-
-private:
-  SessionContext &Session;
-  std::unique_ptr<Module> M;
-  IRBuilder<> Builder;
-};
-
-Function* IRGenContext::getPrototype(const std::string &Name) {
-  if (Function *ExistingProto = M->getFunction(Name))
-    return ExistingProto;
-  if (PrototypeAST *ProtoAST = Session.getPrototypeAST(Name))
-    return ProtoAST->IRGen(*this);
-  return nullptr;
-}
-
-/// CreateEntryBlockAlloca - Create an alloca instruction in the entry block of
-/// the function.  This is used for mutable variables etc.
-static AllocaInst *CreateEntryBlockAlloca(Function *TheFunction,
-                                          const std::string &VarName) {
-  IRBuilder<> TmpB(&TheFunction->getEntryBlock(),
-                   TheFunction->getEntryBlock().begin());
-  return TmpB.CreateAlloca(Type::getDoubleTy(TheFunction->getContext()),
-                           nullptr, VarName);
-}
-
-Value *NumberExprAST::IRGen(IRGenContext &C) const {
-  return ConstantFP::get(C.getLLVMContext(), APFloat(Val));
-}
-
-Value *VariableExprAST::IRGen(IRGenContext &C) const {
-  // Look this variable up in the function.
-  Value *V = C.NamedValues[Name];
-
-  if (!V)
-    return ErrorP<Value>("Unknown variable name '" + Name + "'");
-
-  // Load the value.
-  return C.getBuilder().CreateLoad(V, Name.c_str());
-}
-
-Value *UnaryExprAST::IRGen(IRGenContext &C) const {
-  if (Value *OperandV = Operand->IRGen(C)) {
-    std::string FnName = MakeLegalFunctionName(std::string("unary")+Opcode);
-    if (Function *F = C.getPrototype(FnName))
-      return C.getBuilder().CreateCall(F, OperandV, "unop");
-    return ErrorP<Value>("Unknown unary operator");
-  }
-
-  // Could not codegen operand - return null.
-  return nullptr;
-}
-
-Value *BinaryExprAST::IRGen(IRGenContext &C) const {
-  // Special case '=' because we don't want to emit the LHS as an expression.
-  if (Op == '=') {
-    // Assignment requires the LHS to be an identifier.
-    auto &LHSVar = static_cast<VariableExprAST &>(*LHS);
-    // Codegen the RHS.
-    Value *Val = RHS->IRGen(C);
-    if (!Val) return nullptr;
-
-    // Look up the name.
-    if (auto Variable = C.NamedValues[LHSVar.Name]) {
-      C.getBuilder().CreateStore(Val, Variable);
-      return Val;
-    }
-    return ErrorP<Value>("Unknown variable name");
-  }
-
-  Value *L = LHS->IRGen(C);
-  Value *R = RHS->IRGen(C);
-  if (!L || !R) return nullptr;
-
-  switch (Op) {
-  case '+': return C.getBuilder().CreateFAdd(L, R, "addtmp");
-  case '-': return C.getBuilder().CreateFSub(L, R, "subtmp");
-  case '*': return C.getBuilder().CreateFMul(L, R, "multmp");
-  case '/': return C.getBuilder().CreateFDiv(L, R, "divtmp");
-  case '<':
-    L = C.getBuilder().CreateFCmpULT(L, R, "cmptmp");
-    // Convert bool 0/1 to double 0.0 or 1.0
-    return C.getBuilder().CreateUIToFP(L, Type::getDoubleTy(C.getLLVMContext()),
-                                       "booltmp");
-  default: break;
-  }
-
-  // If it wasn't a builtin binary operator, it must be a user defined one. Emit
-  // a call to it.
-  std::string FnName = MakeLegalFunctionName(std::string("binary")+Op);
-  if (Function *F = C.getPrototype(FnName)) {
-    Value *Ops[] = { L, R };
-    return C.getBuilder().CreateCall(F, Ops, "binop");
-  }
-
-  return ErrorP<Value>("Unknown binary operator");
-}
-
-Value *CallExprAST::IRGen(IRGenContext &C) const {
-  // Look up the name in the global module table.
-  if (auto CalleeF = C.getPrototype(CalleeName)) {
-    // If argument mismatch error.
-    if (CalleeF->arg_size() != Args.size())
-      return ErrorP<Value>("Incorrect # arguments passed");
-
-    std::vector<Value*> ArgsV;
-    for (unsigned i = 0, e = Args.size(); i != e; ++i) {
-      ArgsV.push_back(Args[i]->IRGen(C));
-      if (!ArgsV.back()) return nullptr;
-    }
-
-    return C.getBuilder().CreateCall(CalleeF, ArgsV, "calltmp");
-  }
-
-  return ErrorP<Value>("Unknown function referenced");
-}
-
-Value *IfExprAST::IRGen(IRGenContext &C) const {
-  Value *CondV = Cond->IRGen(C);
-  if (!CondV) return nullptr;
-
-  // Convert condition to a bool by comparing equal to 0.0.
-  ConstantFP *FPZero =
-    ConstantFP::get(C.getLLVMContext(), APFloat(0.0));
-  CondV = C.getBuilder().CreateFCmpONE(CondV, FPZero, "ifcond");
-
-  Function *TheFunction = C.getBuilder().GetInsertBlock()->getParent();
-
-  // Create blocks for the then and else cases.  Insert the 'then' block at the
-  // end of the function.
-  BasicBlock *ThenBB = BasicBlock::Create(C.getLLVMContext(), "then", TheFunction);
-  BasicBlock *ElseBB = BasicBlock::Create(C.getLLVMContext(), "else");
-  BasicBlock *MergeBB = BasicBlock::Create(C.getLLVMContext(), "ifcont");
-
-  C.getBuilder().CreateCondBr(CondV, ThenBB, ElseBB);
-
-  // Emit then value.
-  C.getBuilder().SetInsertPoint(ThenBB);
-
-  Value *ThenV = Then->IRGen(C);
-  if (!ThenV) return nullptr;
-
-  C.getBuilder().CreateBr(MergeBB);
-  // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
-  ThenBB = C.getBuilder().GetInsertBlock();
-
-  // Emit else block.
-  TheFunction->getBasicBlockList().push_back(ElseBB);
-  C.getBuilder().SetInsertPoint(ElseBB);
-
-  Value *ElseV = Else->IRGen(C);
-  if (!ElseV) return nullptr;
-
-  C.getBuilder().CreateBr(MergeBB);
-  // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
-  ElseBB = C.getBuilder().GetInsertBlock();
-
-  // Emit merge block.
-  TheFunction->getBasicBlockList().push_back(MergeBB);
-  C.getBuilder().SetInsertPoint(MergeBB);
-  PHINode *PN = C.getBuilder().CreatePHI(Type::getDoubleTy(C.getLLVMContext()),
-                                         2, "iftmp");
-
-  PN->addIncoming(ThenV, ThenBB);
-  PN->addIncoming(ElseV, ElseBB);
-  return PN;
-}
-
-Value *ForExprAST::IRGen(IRGenContext &C) const {
-  // Output this as:
-  //   var = alloca double
-  //   ...
-  //   start = startexpr
-  //   store start -> var
-  //   goto loop
-  // loop:
-  //   ...
-  //   bodyexpr
-  //   ...
-  // loopend:
-  //   step = stepexpr
-  //   endcond = endexpr
-  //
-  //   curvar = load var
-  //   nextvar = curvar + step
-  //   store nextvar -> var
-  //   br endcond, loop, endloop
-  // outloop:
-
-  Function *TheFunction = C.getBuilder().GetInsertBlock()->getParent();
-
-  // Create an alloca for the variable in the entry block.
-  AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
-
-  // Emit the start code first, without 'variable' in scope.
-  Value *StartVal = Start->IRGen(C);
-  if (!StartVal) return nullptr;
-
-  // Store the value into the alloca.
-  C.getBuilder().CreateStore(StartVal, Alloca);
-
-  // Make the new basic block for the loop header, inserting after current
-  // block.
-  BasicBlock *LoopBB =
-      BasicBlock::Create(C.getLLVMContext(), "loop", TheFunction);
-
-  // Insert an explicit fall through from the current block to the LoopBB.
-  C.getBuilder().CreateBr(LoopBB);
-
-  // Start insertion in LoopBB.
-  C.getBuilder().SetInsertPoint(LoopBB);
-
-  // Within the loop, the variable is defined equal to the PHI node.  If it
-  // shadows an existing variable, we have to restore it, so save it now.
-  AllocaInst *OldVal = C.NamedValues[VarName];
-  C.NamedValues[VarName] = Alloca;
-
-  // Emit the body of the loop.  This, like any other expr, can change the
-  // current BB.  Note that we ignore the value computed by the body, but don't
-  // allow an error.
-  if (!Body->IRGen(C))
-    return nullptr;
-
-  // Emit the step value.
-  Value *StepVal;
-  if (Step) {
-    StepVal = Step->IRGen(C);
-    if (!StepVal) return nullptr;
-  } else {
-    // If not specified, use 1.0.
-    StepVal = ConstantFP::get(C.getLLVMContext(), APFloat(1.0));
-  }
-
-  // Compute the end condition.
-  Value *EndCond = End->IRGen(C);
-  if (!EndCond) return nullptr;
-
-  // Reload, increment, and restore the alloca.  This handles the case where
-  // the body of the loop mutates the variable.
-  Value *CurVar = C.getBuilder().CreateLoad(Alloca, VarName.c_str());
-  Value *NextVar = C.getBuilder().CreateFAdd(CurVar, StepVal, "nextvar");
-  C.getBuilder().CreateStore(NextVar, Alloca);
-
-  // Convert condition to a bool by comparing equal to 0.0.
-  EndCond = C.getBuilder().CreateFCmpONE(
-      EndCond, ConstantFP::get(C.getLLVMContext(), APFloat(0.0)), "loopcond");
-
-  // Create the "after loop" block and insert it.
-  BasicBlock *AfterBB =
-      BasicBlock::Create(C.getLLVMContext(), "afterloop", TheFunction);
-
-  // Insert the conditional branch into the end of LoopEndBB.
-  C.getBuilder().CreateCondBr(EndCond, LoopBB, AfterBB);
-
-  // Any new code will be inserted in AfterBB.
-  C.getBuilder().SetInsertPoint(AfterBB);
-
-  // Restore the unshadowed variable.
-  if (OldVal)
-    C.NamedValues[VarName] = OldVal;
-  else
-    C.NamedValues.erase(VarName);
-
-  // for expr always returns 0.0.
-  return Constant::getNullValue(Type::getDoubleTy(C.getLLVMContext()));
-}
-
-Value *VarExprAST::IRGen(IRGenContext &C) const {
-  std::vector<AllocaInst *> OldBindings;
-
-  Function *TheFunction = C.getBuilder().GetInsertBlock()->getParent();
-
-  // Register all variables and emit their initializer.
-  for (unsigned i = 0, e = VarBindings.size(); i != e; ++i) {
-    auto &VarName = VarBindings[i].first;
-    auto &Init = VarBindings[i].second;
-
-    // Emit the initializer before adding the variable to scope, this prevents
-    // the initializer from referencing the variable itself, and permits stuff
-    // like this:
-    //  var a = 1 in
-    //    var a = a in ...   # refers to outer 'a'.
-    Value *InitVal;
-    if (Init) {
-      InitVal = Init->IRGen(C);
-      if (!InitVal) return nullptr;
-    } else // If not specified, use 0.0.
-      InitVal = ConstantFP::get(C.getLLVMContext(), APFloat(0.0));
-
-    AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
-    C.getBuilder().CreateStore(InitVal, Alloca);
-
-    // Remember the old variable binding so that we can restore the binding when
-    // we unrecurse.
-    OldBindings.push_back(C.NamedValues[VarName]);
-
-    // Remember this binding.
-    C.NamedValues[VarName] = Alloca;
-  }
-
-  // Codegen the body, now that all vars are in scope.
-  Value *BodyVal = Body->IRGen(C);
-  if (!BodyVal) return nullptr;
-
-  // Pop all our variables from scope.
-  for (unsigned i = 0, e = VarBindings.size(); i != e; ++i)
-    C.NamedValues[VarBindings[i].first] = OldBindings[i];
-
-  // Return the body computation.
-  return BodyVal;
-}
-
-Function *PrototypeAST::IRGen(IRGenContext &C) const {
-  std::string FnName = MakeLegalFunctionName(Name);
-
-  // Make the function type:  double(double,double) etc.
-  std::vector<Type *> Doubles(Args.size(),
-                              Type::getDoubleTy(C.getLLVMContext()));
-  FunctionType *FT =
-      FunctionType::get(Type::getDoubleTy(C.getLLVMContext()), Doubles, false);
-  Function *F = Function::Create(FT, Function::ExternalLinkage, FnName,
-                                 &C.getM());
-
-  // If F conflicted, there was already something named 'FnName'.  If it has a
-  // body, don't allow redefinition or reextern.
-  if (F->getName() != FnName) {
-    // Delete the one we just made and get the existing one.
-    F->eraseFromParent();
-    F = C.getM().getFunction(Name);
-
-    // If F already has a body, reject this.
-    if (!F->empty()) {
-      ErrorP<Function>("redefinition of function");
-      return nullptr;
-    }
-
-    // If F took a different number of args, reject.
-    if (F->arg_size() != Args.size()) {
-      ErrorP<Function>("redefinition of function with different # args");
-      return nullptr;
-    }
-  }
-
-  // Set names for all arguments.
-  unsigned Idx = 0;
-  for (Function::arg_iterator AI = F->arg_begin(); Idx != Args.size();
-       ++AI, ++Idx)
-    AI->setName(Args[Idx]);
-
-  return F;
-}
-
-/// CreateArgumentAllocas - Create an alloca for each argument and register the
-/// argument in the symbol table so that references to it will succeed.
-void PrototypeAST::CreateArgumentAllocas(Function *F, IRGenContext &C) {
-  Function::arg_iterator AI = F->arg_begin();
-  for (unsigned Idx = 0, e = Args.size(); Idx != e; ++Idx, ++AI) {
-    // Create an alloca for this variable.
-    AllocaInst *Alloca = CreateEntryBlockAlloca(F, Args[Idx]);
-
-    // Store the initial value into the alloca.
-    C.getBuilder().CreateStore(&*AI, Alloca);
-
-    // Add arguments to variable symbol table.
-    C.NamedValues[Args[Idx]] = Alloca;
-  }
-}
-
-Function *FunctionAST::IRGen(IRGenContext &C) const {
-  C.NamedValues.clear();
-
-  Function *TheFunction = Proto->IRGen(C);
-  if (!TheFunction)
-    return nullptr;
-
-  // If this is an operator, install it.
-  if (Proto->isBinaryOp())
-    BinopPrecedence[Proto->getOperatorName()] = Proto->Precedence;
-
-  // Create a new basic block to start insertion into.
-  BasicBlock *BB = BasicBlock::Create(C.getLLVMContext(), "entry", TheFunction);
-  C.getBuilder().SetInsertPoint(BB);
-
-  // Add all arguments to the symbol table and create their allocas.
-  Proto->CreateArgumentAllocas(TheFunction, C);
-
-  if (Value *RetVal = Body->IRGen(C)) {
-    // Finish off the function.
-    C.getBuilder().CreateRet(RetVal);
-
-    // Validate the generated code, checking for consistency.
-    verifyFunction(*TheFunction);
-
-    return TheFunction;
-  }
-
-  // Error reading body, remove function.
-  TheFunction->eraseFromParent();
-
-  if (Proto->isBinaryOp())
-    BinopPrecedence.erase(Proto->getOperatorName());
-  return nullptr;
-}
-
-//===----------------------------------------------------------------------===//
-// Top-Level parsing and JIT Driver
-//===----------------------------------------------------------------------===//
-
-static std::unique_ptr<llvm::Module> IRGen(SessionContext &S,
-                                           const FunctionAST &F) {
-  IRGenContext C(S);
-  auto LF = F.IRGen(C);
-  if (!LF)
-    return nullptr;
-#ifndef MINIMAL_STDERR_OUTPUT
-  fprintf(stderr, "Read function definition:");
-  LF->dump();
-#endif
-  return C.takeM();
-}
-
-template <typename T>
-static std::vector<T> singletonSet(T t) {
-  std::vector<T> Vec;
-  Vec.push_back(std::move(t));
-  return Vec;
-}
-
-static void EarthShatteringKaboom() {
-  fprintf(stderr, "Earth shattering kaboom.");
-  exit(1);
-}
-
-class KaleidoscopeJIT {
-public:
-  typedef ObjectLinkingLayer<> ObjLayerT;
-  typedef IRCompileLayer<ObjLayerT> CompileLayerT;
-  typedef LazyEmittingLayer<CompileLayerT> LazyEmitLayerT;
-  typedef LazyEmitLayerT::ModuleSetHandleT ModuleHandleT;
-
-  KaleidoscopeJIT(SessionContext &Session)
-    : Session(Session),
-      CompileLayer(ObjectLayer, SimpleCompiler(Session.getTarget())),
-      LazyEmitLayer(CompileLayer),
-      CompileCallbacks(reinterpret_cast<uintptr_t>(EarthShatteringKaboom)) {}
-
-  std::string mangle(const std::string &Name) {
-    std::string MangledName;
-    {
-      raw_string_ostream MangledNameStream(MangledName);
-      Mangler::getNameWithPrefix(MangledNameStream, Name,
-                                 Session.getTarget().createDataLayout());
-    }
-    return MangledName;
-  }
-
-  void addFunctionAST(std::unique_ptr<FunctionAST> FnAST) {
-    std::cerr << "Adding AST: " << FnAST->Proto->Name << "\n";
-    FunctionDefs[mangle(FnAST->Proto->Name)] = std::move(FnAST);
-  }
-
-  ModuleHandleT addModule(std::unique_ptr<Module> M) {
-    // We need a memory manager to allocate memory and resolve symbols for this
-    // new module. Create one that resolves symbols by looking back into the
-    // JIT.
-    auto Resolver = createLambdaResolver(
-                      [&](const std::string &Name) {
-                        // First try to find 'Name' within the JIT.
-                        if (auto Symbol = findSymbol(Name))
-                          return RuntimeDyld::SymbolInfo(Symbol.getAddress(),
-                                                         Symbol.getFlags());
-
-                        // If we don't already have a definition of 'Name' then search
-                        // the ASTs.
-                        return searchFunctionASTs(Name);
-                      },
-                      [](const std::string &S) { return nullptr; } );
-
-    return LazyEmitLayer.addModuleSet(singletonSet(std::move(M)),
-                                      make_unique<SectionMemoryManager>(),
-                                      std::move(Resolver));
-  }
-
-  void removeModule(ModuleHandleT H) { LazyEmitLayer.removeModuleSet(H); }
-
-  JITSymbol findSymbol(const std::string &Name) {
-    return LazyEmitLayer.findSymbol(Name, false);
-  }
-
-  JITSymbol findSymbolIn(ModuleHandleT H, const std::string &Name) {
-    return LazyEmitLayer.findSymbolIn(H, Name, false);
-  }
-
-  JITSymbol findUnmangledSymbol(const std::string &Name) {
-    return findSymbol(mangle(Name));
-  }
-
-  JITSymbol findUnmangledSymbolIn(ModuleHandleT H, const std::string &Name) {
-    return findSymbolIn(H, mangle(Name));
-  }
-
-private:
-  // This method searches the FunctionDefs map for a definition of 'Name'. If it
-  // finds one it generates a stub for it and returns the address of the stub.
-  RuntimeDyld::SymbolInfo searchFunctionASTs(const std::string &Name) {
-    auto DefI = FunctionDefs.find(Name);
-    if (DefI == FunctionDefs.end())
-      return nullptr;
-
-    // Return the address of the stub.
-    // Take the FunctionAST out of the map.
-    auto FnAST = std::move(DefI->second);
-    FunctionDefs.erase(DefI);
-
-    // IRGen the AST, add it to the JIT, and return the address for it.
-    auto H = irGenStub(std::move(FnAST));
-    auto Sym = findSymbolIn(H, Name);
-    return RuntimeDyld::SymbolInfo(Sym.getAddress(), Sym.getFlags());
-  }
-
-  // This method will take the AST for a function definition and IR-gen a stub
-  // for that function that will, on first call, IR-gen the actual body of the
-  // function.
-  ModuleHandleT irGenStub(std::unique_ptr<FunctionAST> FnAST) {
-    // Step 1) IRGen a prototype for the stub. This will have the same type as
-    //         the function.
-    IRGenContext C(Session);
-    Function *F = FnAST->Proto->IRGen(C);
-
-    // Step 2) Get a compile callback that can be used to compile the body of
-    //         the function. The resulting CallbackInfo type will let us set the
-    //         compile and update actions for the callback, and get a pointer to
-    //         the jit trampoline that we need to call to trigger those actions.
-    auto CallbackInfo = CompileCallbacks.getCompileCallback();
-
-    // Step 3) Create a stub that will indirectly call the body of this
-    //         function once it is compiled. Initially, set the function
-    //         pointer for the indirection to point at the trampoline.
-    std::string BodyPtrName = (F->getName() + "$address").str();
-    GlobalVariable *FunctionBodyPointer =
-      createImplPointer(*F->getType(), *F->getParent(), BodyPtrName,
-                        createIRTypedAddress(*F->getFunctionType(),
-                                             CallbackInfo.getAddress()));
-    makeStub(*F, *FunctionBodyPointer);
-
-    // Step 4) Add the module containing the stub to the JIT.
-    auto StubH = addModule(C.takeM());
-
-    // Step 5) Set the compile and update actions.
-    //
-    //   The compile action will IRGen the function and add it to the JIT, then
-    // request its address, which will trigger codegen. Since we don't need the
-    // AST after this, we pass ownership of the AST into the compile action:
-    // compile actions (and update actions) are deleted after they're run, so
-    // this will free the AST for us.
-    //
-    //   The update action will update FunctionBodyPointer to point at the newly
-    // compiled function.
-    std::shared_ptr<FunctionAST> Fn = std::move(FnAST);
-    CallbackInfo.setCompileAction([this, Fn, BodyPtrName, StubH]() {
-      auto H = addModule(IRGen(Session, *Fn));
-      auto BodySym = findUnmangledSymbolIn(H, Fn->Proto->Name);
-      auto BodyPtrSym = findUnmangledSymbolIn(StubH, BodyPtrName);
-      assert(BodySym && "Missing function body.");
-      assert(BodyPtrSym && "Missing function pointer.");
-      auto BodyAddr = BodySym.getAddress();
-      auto BodyPtr = reinterpret_cast<void*>(
-                       static_cast<uintptr_t>(BodyPtrSym.getAddress()));
-      memcpy(BodyPtr, &BodyAddr, sizeof(uintptr_t));
-      return BodyAddr;
-    });
-
-    return StubH;
-  }
-
-  SessionContext &Session;
-  SectionMemoryManager CCMgrMemMgr;
-  ObjLayerT ObjectLayer;
-  CompileLayerT CompileLayer;
-  LazyEmitLayerT LazyEmitLayer;
-
-  std::map<std::string, std::unique_ptr<FunctionAST>> FunctionDefs;
-
-  LocalJITCompileCallbackManager<OrcX86_64_SysV> CompileCallbacks;
-};
-
-static void HandleDefinition(SessionContext &S, KaleidoscopeJIT &J) {
-  if (auto F = ParseDefinition()) {
-    S.addPrototypeAST(llvm::make_unique<PrototypeAST>(*F->Proto));
-    J.addFunctionAST(std::move(F));
-  } else {
-    // Skip token for error recovery.
-    getNextToken();
-  }
-}
-
-static void HandleExtern(SessionContext &S) {
-  if (auto P = ParseExtern())
-    S.addPrototypeAST(std::move(P));
-  else {
-    // Skip token for error recovery.
-    getNextToken();
-  }
-}
-
-static void HandleTopLevelExpression(SessionContext &S, KaleidoscopeJIT &J) {
-  // Evaluate a top-level expression into an anonymous function.
-  if (auto F = ParseTopLevelExpr()) {
-    IRGenContext C(S);
-    if (auto ExprFunc = F->IRGen(C)) {
-#ifndef MINIMAL_STDERR_OUTPUT
-      std::cerr << "Expression function:\n";
-      ExprFunc->dump();
-#endif
-      // Add the CodeGen'd module to the JIT. Keep a handle to it: We can remove
-      // this module as soon as we've executed Function ExprFunc.
-      auto H = J.addModule(C.takeM());
-
-      // Get the address of the JIT'd function in memory.
-      auto ExprSymbol = J.findUnmangledSymbol("__anon_expr");
-
-      // Cast it to the right type (takes no arguments, returns a double) so we
-      // can call it as a native function.
-      double (*FP)() = (double (*)())(intptr_t)ExprSymbol.getAddress();
-#ifdef MINIMAL_STDERR_OUTPUT
-      FP();
-#else
-      std::cerr << "Evaluated to " << FP() << "\n";
-#endif
-
-      // Remove the function.
-      J.removeModule(H);
-    }
-  } else {
-    // Skip token for error recovery.
-    getNextToken();
-  }
-}
-
-/// top ::= definition | external | expression | ';'
-static void MainLoop() {
-  LLVMContext TheContext;
-  SessionContext S(TheContext);
-  KaleidoscopeJIT J(S);
-
-  while (true) {
-    switch (CurTok) {
-    case tok_eof:    return;
-    case ';':        getNextToken(); continue;  // ignore top-level semicolons.
-    case tok_def:    HandleDefinition(S, J); break;
-    case tok_extern: HandleExtern(S); break;
-    default:         HandleTopLevelExpression(S, J); break;
-    }
-#ifndef MINIMAL_STDERR_OUTPUT
-    std::cerr << "ready> ";
-#endif
-  }
-}
-
-//===----------------------------------------------------------------------===//
-// "Library" functions that can be "extern'd" from user code.
-//===----------------------------------------------------------------------===//
-
-/// putchard - putchar that takes a double and returns 0.
-extern "C"
-double putchard(double X) {
-  putchar((char)X);
-  return 0;
-}
-
-/// printd - printf that takes a double prints it as "%f\n", returning 0.
-extern "C"
-double printd(double X) {
-  printf("%f", X);
-  return 0;
-}
-
-extern "C"
-double printlf() {
-  printf("\n");
-  return 0;
-}
-
-//===----------------------------------------------------------------------===//
-// Main driver code.
-//===----------------------------------------------------------------------===//
-
-int main() {
-  InitializeNativeTarget();
-  InitializeNativeTargetAsmPrinter();
-  InitializeNativeTargetAsmParser();
-
-  // Install standard binary operators.
-  // 1 is lowest precedence.
-  BinopPrecedence['='] = 2;
-  BinopPrecedence['<'] = 10;
-  BinopPrecedence['+'] = 20;
-  BinopPrecedence['-'] = 20;
-  BinopPrecedence['/'] = 40;
-  BinopPrecedence['*'] = 40;  // highest.
-
-  // Prime the first token.
-#ifndef MINIMAL_STDERR_OUTPUT
-  std::cerr << "ready> ";
-#endif
-  getNextToken();
-
-  std::cerr << std::fixed;
-
-  // Run the main "interpreter loop" now.
-  MainLoop();
-
-  return 0;
-}
diff --git a/examples/Kaleidoscope/Orc/initial/CMakeLists.txt b/examples/Kaleidoscope/Orc/initial/CMakeLists.txt
deleted file mode 100644
index 4f21e1c6221..00000000000
--- a/examples/Kaleidoscope/Orc/initial/CMakeLists.txt
+++ /dev/null
@@ -1,12 +0,0 @@
-set(LLVM_LINK_COMPONENTS
-  Core
-  ExecutionEngine
-  Object
-  RuntimeDyld
-  Support
-  native
-  )
-
-add_kaleidoscope_chapter(Kaleidoscope-Orc-initial
-  toy.cpp
-  )
diff --git a/examples/Kaleidoscope/Orc/initial/README.txt b/examples/Kaleidoscope/Orc/initial/README.txt
deleted file mode 100644
index 5f4cbbfe3d2..00000000000
--- a/examples/Kaleidoscope/Orc/initial/README.txt
+++ /dev/null
@@ -1,13 +0,0 @@
-//===----------------------------------------------------------------------===/
-//                 Kaleidoscope with Orc - Initial Version
-//===----------------------------------------------------------------------===//
-
-This version of Kaleidoscope with Orc demonstrates fully eager compilation. When
-a function definition or top-level expression is entered it is immediately
-translated (IRGen'd) to LLVM IR and added to the JIT, where it is code-gen'd to
-native code and either stored (for function definitions) or executed (for
-top-level expressions).
-
-This directory contain a Makefile that allow the code to be built in a
-standalone manner, independent of the larger LLVM build infrastructure. To build
-the program you will need to have 'clang++' and 'llvm-config' in your path.
diff --git a/examples/Kaleidoscope/Orc/initial/toy.cpp b/examples/Kaleidoscope/Orc/initial/toy.cpp
deleted file mode 100644
index 21f59fc1730..00000000000
--- a/examples/Kaleidoscope/Orc/initial/toy.cpp
+++ /dev/null
@@ -1,1356 +0,0 @@
-#include "llvm/ADT/APFloat.h"
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ExecutionEngine/ExecutionEngine.h"
-#include "llvm/ExecutionEngine/RuntimeDyld.h"
-#include "llvm/ExecutionEngine/SectionMemoryManager.h"
-#include "llvm/ExecutionEngine/Orc/CompileUtils.h"
-#include "llvm/ExecutionEngine/Orc/IRCompileLayer.h"
-#include "llvm/ExecutionEngine/Orc/JITSymbol.h"
-#include "llvm/ExecutionEngine/Orc/LambdaResolver.h"
-#include "llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h"
-#include "llvm/IR/BasicBlock.h"
-#include "llvm/IR/Constant.h"
-#include "llvm/IR/Constants.h"
-#include "llvm/IR/DataLayout.h"
-#include "llvm/IR/DerivedTypes.h"
-#include "llvm/IR/Function.h"
-#include "llvm/IR/Instructions.h"
-#include "llvm/IR/IRBuilder.h"
-#include "llvm/IR/LLVMContext.h"
-#include "llvm/IR/Mangler.h"
-#include "llvm/IR/Module.h"
-#include "llvm/IR/Type.h"
-#include "llvm/IR/Verifier.h"
-#include "llvm/Support/raw_ostream.h"
-#include "llvm/Support/TargetSelect.h"
-#include "llvm/Target/TargetMachine.h"
-#include <cassert>
-#include <cctype>
-#include <cstdint>
-#include <cstdio>
-#include <cstdlib>
-#include <iomanip>
-#include <iostream>
-#include <map>
-#include <memory>
-#include <sstream>
-#include <string>
-#include <utility>
-#include <vector>
-
-using namespace llvm;
-using namespace llvm::orc;
-
-//===----------------------------------------------------------------------===//
-// Lexer
-//===----------------------------------------------------------------------===//
-
-// The lexer returns tokens [0-255] if it is an unknown character, otherwise one
-// of these for known things.
-enum Token {
-  tok_eof = -1,
-
-  // commands
-  tok_def = -2, tok_extern = -3,
-
-  // primary
-  tok_identifier = -4, tok_number = -5,
-
-  // control
-  tok_if = -6, tok_then = -7, tok_else = -8,
-  tok_for = -9, tok_in = -10,
-
-  // operators
-  tok_binary = -11, tok_unary = -12,
-
-  // var definition
-  tok_var = -13
-};
-
-static std::string IdentifierStr;  // Filled in if tok_identifier
-static double NumVal;              // Filled in if tok_number
-
-/// gettok - Return the next token from standard input.
-static int gettok() {
-  static int LastChar = ' ';
-
-  // Skip any whitespace.
-  while (isspace(LastChar))
-    LastChar = getchar();
-
-  if (isalpha(LastChar)) { // identifier: [a-zA-Z][a-zA-Z0-9]*
-    IdentifierStr = LastChar;
-    while (isalnum((LastChar = getchar())))
-      IdentifierStr += LastChar;
-
-    if (IdentifierStr == "def") return tok_def;
-    if (IdentifierStr == "extern") return tok_extern;
-    if (IdentifierStr == "if") return tok_if;
-    if (IdentifierStr == "then") return tok_then;
-    if (IdentifierStr == "else") return tok_else;
-    if (IdentifierStr == "for") return tok_for;
-    if (IdentifierStr == "in") return tok_in;
-    if (IdentifierStr == "binary") return tok_binary;
-    if (IdentifierStr == "unary") return tok_unary;
-    if (IdentifierStr == "var") return tok_var;
-    return tok_identifier;
-  }
-
-  if (isdigit(LastChar) || LastChar == '.') {   // Number: [0-9.]+
-    std::string NumStr;
-    do {
-      NumStr += LastChar;
-      LastChar = getchar();
-    } while (isdigit(LastChar) || LastChar == '.');
-
-    NumVal = strtod(NumStr.c_str(), nullptr);
-    return tok_number;
-  }
-
-  if (LastChar == '#') {
-    // Comment until end of line.
-    do LastChar = getchar();
-    while (LastChar != EOF && LastChar != '\n' && LastChar != '\r');
-
-    if (LastChar != EOF)
-      return gettok();
-  }
-
-  // Check for end of file.  Don't eat the EOF.
-  if (LastChar == EOF)
-    return tok_eof;
-
-  // Otherwise, just return the character as its ascii value.
-  int ThisChar = LastChar;
-  LastChar = getchar();
-  return ThisChar;
-}
-
-//===----------------------------------------------------------------------===//
-// Abstract Syntax Tree (aka Parse Tree)
-//===----------------------------------------------------------------------===//
-
-class IRGenContext;
-
-/// ExprAST - Base class for all expression nodes.
-struct ExprAST {
-  virtual ~ExprAST() {}
-  virtual Value *IRGen(IRGenContext &C) const = 0;
-};
-
-/// NumberExprAST - Expression class for numeric literals like "1.0".
-struct NumberExprAST : public ExprAST {
-  NumberExprAST(double Val) : Val(Val) {}
-  Value *IRGen(IRGenContext &C) const override;
-
-  double Val;
-};
-
-/// VariableExprAST - Expression class for referencing a variable, like "a".
-struct VariableExprAST : public ExprAST {
-  VariableExprAST(std::string Name) : Name(std::move(Name)) {}
-  Value *IRGen(IRGenContext &C) const override;
-
-  std::string Name;
-};
-
-/// UnaryExprAST - Expression class for a unary operator.
-struct UnaryExprAST : public ExprAST {
-  UnaryExprAST(char Opcode, std::unique_ptr<ExprAST> Operand)
-    : Opcode(std::move(Opcode)), Operand(std::move(Operand)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  char Opcode;
-  std::unique_ptr<ExprAST> Operand;
-};
-
-/// BinaryExprAST - Expression class for a binary operator.
-struct BinaryExprAST : public ExprAST {
-  BinaryExprAST(char Op, std::unique_ptr<ExprAST> LHS,
-                std::unique_ptr<ExprAST> RHS)
-    : Op(Op), LHS(std::move(LHS)), RHS(std::move(RHS)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  char Op;
-  std::unique_ptr<ExprAST> LHS, RHS;
-};
-
-/// CallExprAST - Expression class for function calls.
-struct CallExprAST : public ExprAST {
-  CallExprAST(std::string CalleeName,
-              std::vector<std::unique_ptr<ExprAST>> Args)
-    : CalleeName(std::move(CalleeName)), Args(std::move(Args)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  std::string CalleeName;
-  std::vector<std::unique_ptr<ExprAST>> Args;
-};
-
-/// IfExprAST - Expression class for if/then/else.
-struct IfExprAST : public ExprAST {
-  IfExprAST(std::unique_ptr<ExprAST> Cond, std::unique_ptr<ExprAST> Then,
-            std::unique_ptr<ExprAST> Else)
-    : Cond(std::move(Cond)), Then(std::move(Then)), Else(std::move(Else)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  std::unique_ptr<ExprAST> Cond, Then, Else;
-};
-
-/// ForExprAST - Expression class for for/in.
-struct ForExprAST : public ExprAST {
-  ForExprAST(std::string VarName, std::unique_ptr<ExprAST> Start,
-             std::unique_ptr<ExprAST> End, std::unique_ptr<ExprAST> Step,
-             std::unique_ptr<ExprAST> Body)
-    : VarName(std::move(VarName)), Start(std::move(Start)), End(std::move(End)),
-      Step(std::move(Step)), Body(std::move(Body)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  std::string VarName;
-  std::unique_ptr<ExprAST> Start, End, Step, Body;
-};
-
-/// VarExprAST - Expression class for var/in
-struct VarExprAST : public ExprAST {
-  typedef std::pair<std::string, std::unique_ptr<ExprAST>> Binding;
-  typedef std::vector<Binding> BindingList;
-
-  VarExprAST(BindingList VarBindings, std::unique_ptr<ExprAST> Body)
-    : VarBindings(std::move(VarBindings)), Body(std::move(Body)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  BindingList VarBindings;
-  std::unique_ptr<ExprAST> Body;
-};
-
-/// PrototypeAST - This class represents the "prototype" for a function,
-/// which captures its argument names as well as if it is an operator.
-struct PrototypeAST {
-  PrototypeAST(std::string Name, std::vector<std::string> Args,
-               bool IsOperator = false, unsigned Precedence = 0)
-    : Name(std::move(Name)), Args(std::move(Args)), IsOperator(IsOperator),
-      Precedence(Precedence) {}
-
-  Function *IRGen(IRGenContext &C) const;
-  void CreateArgumentAllocas(Function *F, IRGenContext &C);
-
-  bool isUnaryOp() const { return IsOperator && Args.size() == 1; }
-  bool isBinaryOp() const { return IsOperator && Args.size() == 2; }
-
-  char getOperatorName() const {
-    assert(isUnaryOp() || isBinaryOp());
-    return Name[Name.size()-1];
-  }
-
-  std::string Name;
-  std::vector<std::string> Args;
-  bool IsOperator;
-  unsigned Precedence;  // Precedence if a binary op.
-};
-
-/// FunctionAST - This class represents a function definition itself.
-struct FunctionAST {
-  FunctionAST(std::unique_ptr<PrototypeAST> Proto,
-              std::unique_ptr<ExprAST> Body)
-    : Proto(std::move(Proto)), Body(std::move(Body)) {}
-
-  Function *IRGen(IRGenContext &C) const;
-
-  std::unique_ptr<PrototypeAST> Proto;
-  std::unique_ptr<ExprAST> Body;
-};
-
-//===----------------------------------------------------------------------===//
-// Parser
-//===----------------------------------------------------------------------===//
-
-/// CurTok/getNextToken - Provide a simple token buffer.  CurTok is the current
-/// token the parser is looking at.  getNextToken reads another token from the
-/// lexer and updates CurTok with its results.
-static int CurTok;
-static int getNextToken() {
-  return CurTok = gettok();
-}
-
-/// BinopPrecedence - This holds the precedence for each binary operator that is
-/// defined.
-static std::map<char, int> BinopPrecedence;
-
-/// GetTokPrecedence - Get the precedence of the pending binary operator token.
-static int GetTokPrecedence() {
-  if (!isascii(CurTok))
-    return -1;
-
-  // Make sure it's a declared binop.
-  int TokPrec = BinopPrecedence[CurTok];
-  if (TokPrec <= 0) return -1;
-  return TokPrec;
-}
-
-template <typename T>
-std::unique_ptr<T> ErrorU(const std::string &Str) {
-  std::cerr << "Error: " << Str << "\n";
-  return nullptr;
-}
-
-template <typename T>
-T* ErrorP(const std::string &Str) {
-  std::cerr << "Error: " << Str << "\n";
-  return nullptr;
-}
-
-static std::unique_ptr<ExprAST> ParseExpression();
-
-/// identifierexpr
-///   ::= identifier
-///   ::= identifier '(' expression* ')'
-static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
-  std::string IdName = IdentifierStr;
-
-  getNextToken();  // eat identifier.
-
-  if (CurTok != '(') // Simple variable ref.
-    return llvm::make_unique<VariableExprAST>(IdName);
-
-  // Call.
-  getNextToken();  // eat (
-  std::vector<std::unique_ptr<ExprAST>> Args;
-  if (CurTok != ')') {
-    while (true) {
-      auto Arg = ParseExpression();
-      if (!Arg) return nullptr;
-      Args.push_back(std::move(Arg));
-
-      if (CurTok == ')') break;
-
-      if (CurTok != ',')
-        return ErrorU<CallExprAST>("Expected ')' or ',' in argument list");
-      getNextToken();
-    }
-  }
-
-  // Eat the ')'.
-  getNextToken();
-
-  return llvm::make_unique<CallExprAST>(IdName, std::move(Args));
-}
-
-/// numberexpr ::= number
-static std::unique_ptr<NumberExprAST> ParseNumberExpr() {
-  auto Result = llvm::make_unique<NumberExprAST>(NumVal);
-  getNextToken(); // consume the number
-  return Result;
-}
-
-/// parenexpr ::= '(' expression ')'
-static std::unique_ptr<ExprAST> ParseParenExpr() {
-  getNextToken();  // eat (.
-  auto V = ParseExpression();
-  if (!V)
-    return nullptr;
-
-  if (CurTok != ')')
-    return ErrorU<ExprAST>("expected ')'");
-  getNextToken();  // eat ).
-  return V;
-}
-
-/// ifexpr ::= 'if' expression 'then' expression 'else' expression
-static std::unique_ptr<ExprAST> ParseIfExpr() {
-  getNextToken();  // eat the if.
-
-  // condition.
-  auto Cond = ParseExpression();
-  if (!Cond)
-    return nullptr;
-
-  if (CurTok != tok_then)
-    return ErrorU<ExprAST>("expected then");
-  getNextToken();  // eat the then
-
-  auto Then = ParseExpression();
-  if (!Then)
-    return nullptr;
-
-  if (CurTok != tok_else)
-    return ErrorU<ExprAST>("expected else");
-
-  getNextToken();
-
-  auto Else = ParseExpression();
-  if (!Else)
-    return nullptr;
-
-  return llvm::make_unique<IfExprAST>(std::move(Cond), std::move(Then),
-                                      std::move(Else));
-}
-
-/// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression
-static std::unique_ptr<ForExprAST> ParseForExpr() {
-  getNextToken();  // eat the for.
-
-  if (CurTok != tok_identifier)
-    return ErrorU<ForExprAST>("expected identifier after for");
-
-  std::string IdName = IdentifierStr;
-  getNextToken();  // eat identifier.
-
-  if (CurTok != '=')
-    return ErrorU<ForExprAST>("expected '=' after for");
-  getNextToken();  // eat '='.
-
-  auto Start = ParseExpression();
-  if (!Start)
-    return nullptr;
-  if (CurTok != ',')
-    return ErrorU<ForExprAST>("expected ',' after for start value");
-  getNextToken();
-
-  auto End = ParseExpression();
-  if (!End)
-    return nullptr;
-
-  // The step value is optional.
-  std::unique_ptr<ExprAST> Step;
-  if (CurTok == ',') {
-    getNextToken();
-    Step = ParseExpression();
-    if (!Step)
-      return nullptr;
-  }
-
-  if (CurTok != tok_in)
-    return ErrorU<ForExprAST>("expected 'in' after for");
-  getNextToken();  // eat 'in'.
-
-  auto Body = ParseExpression();
-  if (Body)
-    return nullptr;
-
-  return llvm::make_unique<ForExprAST>(IdName, std::move(Start), std::move(End),
-                                       std::move(Step), std::move(Body));
-}
-
-/// varexpr ::= 'var' identifier ('=' expression)?
-//                    (',' identifier ('=' expression)?)* 'in' expression
-static std::unique_ptr<VarExprAST> ParseVarExpr() {
-  getNextToken();  // eat the var.
-
-  VarExprAST::BindingList VarBindings;
-
-  // At least one variable name is required.
-  if (CurTok != tok_identifier)
-    return ErrorU<VarExprAST>("expected identifier after var");
-
-  while (true) {
-    std::string Name = IdentifierStr;
-    getNextToken();  // eat identifier.
-
-    // Read the optional initializer.
-    std::unique_ptr<ExprAST> Init;
-    if (CurTok == '=') {
-      getNextToken(); // eat the '='.
-
-      Init = ParseExpression();
-      if (!Init)
-        return nullptr;
-    }
-
-    VarBindings.push_back(VarExprAST::Binding(Name, std::move(Init)));
-
-    // End of var list, exit loop.
-    if (CurTok != ',') break;
-    getNextToken(); // eat the ','.
-
-    if (CurTok != tok_identifier)
-      return ErrorU<VarExprAST>("expected identifier list after var");
-  }
-
-  // At this point, we have to have 'in'.
-  if (CurTok != tok_in)
-    return ErrorU<VarExprAST>("expected 'in' keyword after 'var'");
-  getNextToken();  // eat 'in'.
-
-  auto Body = ParseExpression();
-  if (!Body)
-    return nullptr;
-
-  return llvm::make_unique<VarExprAST>(std::move(VarBindings), std::move(Body));
-}
-
-/// primary
-///   ::= identifierexpr
-///   ::= numberexpr
-///   ::= parenexpr
-///   ::= ifexpr
-///   ::= forexpr
-///   ::= varexpr
-static std::unique_ptr<ExprAST> ParsePrimary() {
-  switch (CurTok) {
-  default: return ErrorU<ExprAST>("unknown token when expecting an expression");
-  case tok_identifier: return ParseIdentifierExpr();
-  case tok_number:     return ParseNumberExpr();
-  case '(':            return ParseParenExpr();
-  case tok_if:         return ParseIfExpr();
-  case tok_for:        return ParseForExpr();
-  case tok_var:        return ParseVarExpr();
-  }
-}
-
-/// unary
-///   ::= primary
-///   ::= '!' unary
-static std::unique_ptr<ExprAST> ParseUnary() {
-  // If the current token is not an operator, it must be a primary expr.
-  if (!isascii(CurTok) || CurTok == '(' || CurTok == ',')
-    return ParsePrimary();
-
-  // If this is a unary operator, read it.
-  int Opc = CurTok;
-  getNextToken();
-  if (auto Operand = ParseUnary())
-    return llvm::make_unique<UnaryExprAST>(Opc, std::move(Operand));
-  return nullptr;
-}
-
-/// binoprhs
-///   ::= ('+' unary)*
-static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec,
-                                              std::unique_ptr<ExprAST> LHS) {
-  // If this is a binop, find its precedence.
-  while (true) {
-    int TokPrec = GetTokPrecedence();
-
-    // If this is a binop that binds at least as tightly as the current binop,
-    // consume it, otherwise we are done.
-    if (TokPrec < ExprPrec)
-      return LHS;
-
-    // Okay, we know this is a binop.
-    int BinOp = CurTok;
-    getNextToken();  // eat binop
-
-    // Parse the unary expression after the binary operator.
-    auto RHS = ParseUnary();
-    if (!RHS)
-      return nullptr;
-
-    // If BinOp binds less tightly with RHS than the operator after RHS, let
-    // the pending operator take RHS as its LHS.
-    int NextPrec = GetTokPrecedence();
-    if (TokPrec < NextPrec) {
-      RHS = ParseBinOpRHS(TokPrec+1, std::move(RHS));
-      if (!RHS)
-        return nullptr;
-    }
-
-    // Merge LHS/RHS.
-    LHS = llvm::make_unique<BinaryExprAST>(BinOp, std::move(LHS), std::move(RHS));
-  }
-}
-
-/// expression
-///   ::= unary binoprhs
-///
-static std::unique_ptr<ExprAST> ParseExpression() {
-  auto LHS = ParseUnary();
-  if (!LHS)
-    return nullptr;
-
-  return ParseBinOpRHS(0, std::move(LHS));
-}
-
-/// prototype
-///   ::= id '(' id* ')'
-///   ::= binary LETTER number? (id, id)
-///   ::= unary LETTER (id)
-static std::unique_ptr<PrototypeAST> ParsePrototype() {
-  std::string FnName;
-
-  unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.
-  unsigned BinaryPrecedence = 30;
-
-  switch (CurTok) {
-  default:
-    return ErrorU<PrototypeAST>("Expected function name in prototype");
-  case tok_identifier:
-    FnName = IdentifierStr;
-    Kind = 0;
-    getNextToken();
-    break;
-  case tok_unary:
-    getNextToken();
-    if (!isascii(CurTok))
-      return ErrorU<PrototypeAST>("Expected unary operator");
-    FnName = "unary";
-    FnName += (char)CurTok;
-    Kind = 1;
-    getNextToken();
-    break;
-  case tok_binary:
-    getNextToken();
-    if (!isascii(CurTok))
-      return ErrorU<PrototypeAST>("Expected binary operator");
-    FnName = "binary";
-    FnName += (char)CurTok;
-    Kind = 2;
-    getNextToken();
-
-    // Read the precedence if present.
-    if (CurTok == tok_number) {
-      if (NumVal < 1 || NumVal > 100)
-        return ErrorU<PrototypeAST>("Invalid precedecnce: must be 1..100");
-      BinaryPrecedence = (unsigned)NumVal;
-      getNextToken();
-    }
-    break;
-  }
-
-  if (CurTok != '(')
-    return ErrorU<PrototypeAST>("Expected '(' in prototype");
-
-  std::vector<std::string> ArgNames;
-  while (getNextToken() == tok_identifier)
-    ArgNames.push_back(IdentifierStr);
-  if (CurTok != ')')
-    return ErrorU<PrototypeAST>("Expected ')' in prototype");
-
-  // success.
-  getNextToken();  // eat ')'.
-
-  // Verify right number of names for operator.
-  if (Kind && ArgNames.size() != Kind)
-    return ErrorU<PrototypeAST>("Invalid number of operands for operator");
-
-  return llvm::make_unique<PrototypeAST>(FnName, std::move(ArgNames), Kind != 0,
-                                         BinaryPrecedence);
-}
-
-/// definition ::= 'def' prototype expression
-static std::unique_ptr<FunctionAST> ParseDefinition() {
-  getNextToken();  // eat def.
-  auto Proto = ParsePrototype();
-  if (!Proto)
-    return nullptr;
-
-  if (auto Body = ParseExpression())
-    return llvm::make_unique<FunctionAST>(std::move(Proto), std::move(Body));
-  return nullptr;
-}
-
-/// toplevelexpr ::= expression
-static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
-  if (auto E = ParseExpression()) {
-    // Make an anonymous proto.
-    auto Proto =
-      llvm::make_unique<PrototypeAST>("__anon_expr", std::vector<std::string>());
-    return llvm::make_unique<FunctionAST>(std::move(Proto), std::move(E));
-  }
-  return nullptr;
-}
-
-/// external ::= 'extern' prototype
-static std::unique_ptr<PrototypeAST> ParseExtern() {
-  getNextToken();  // eat extern.
-  return ParsePrototype();
-}
-
-//===----------------------------------------------------------------------===//
-// Code Generation
-//===----------------------------------------------------------------------===//
-
-// FIXME: Obviously we can do better than this
-std::string GenerateUniqueName(const std::string &Root) {
-  static int i = 0;
-  std::ostringstream NameStream;
-  NameStream << Root << ++i;
-  return NameStream.str();
-}
-
-std::string MakeLegalFunctionName(std::string Name)
-{
-  std::string NewName;
-  assert(!Name.empty() && "Base name must not be empty");
-
-  // Start with what we have
-  NewName = Name;
-
-  // Look for a numberic first character
-  if (NewName.find_first_of("0123456789") == 0) {
-    NewName.insert(0, 1, 'n');
-  }
-
-  // Replace illegal characters with their ASCII equivalent
-  std::string legal_elements = "_abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
-  size_t pos;
-  while ((pos = NewName.find_first_not_of(legal_elements)) != std::string::npos) {
-    std::ostringstream NumStream;
-    NumStream << (int)NewName.at(pos);
-    NewName = NewName.replace(pos, 1, NumStream.str());
-  }
-
-  return NewName;
-}
-
-class SessionContext {
-public:
-  SessionContext(LLVMContext &C)
-    : Context(C), TM(EngineBuilder().selectTarget()) {}
-  LLVMContext& getLLVMContext() const { return Context; }
-  TargetMachine& getTarget() { return *TM; }
-  void addPrototypeAST(std::unique_ptr<PrototypeAST> P);
-  PrototypeAST* getPrototypeAST(const std::string &Name);
-
-private:
-  typedef std::map<std::string, std::unique_ptr<PrototypeAST>> PrototypeMap;
-
-  LLVMContext &Context;
-  std::unique_ptr<TargetMachine> TM;
-
-  PrototypeMap Prototypes;
-};
-
-void SessionContext::addPrototypeAST(std::unique_ptr<PrototypeAST> P) {
-  Prototypes[P->Name] = std::move(P);
-}
-
-PrototypeAST* SessionContext::getPrototypeAST(const std::string &Name) {
-  PrototypeMap::iterator I = Prototypes.find(Name);
-  if (I != Prototypes.end())
-    return I->second.get();
-  return nullptr;
-}
-
-class IRGenContext {
-public:
-  IRGenContext(SessionContext &S)
-    : Session(S),
-      M(new Module(GenerateUniqueName("jit_module_"),
-                   Session.getLLVMContext())),
-      Builder(Session.getLLVMContext()) {
-    M->setDataLayout(Session.getTarget().createDataLayout());
-  }
-
-  SessionContext& getSession() { return Session; }
-  Module& getM() const { return *M; }
-  std::unique_ptr<Module> takeM() { return std::move(M); }
-  IRBuilder<>& getBuilder() { return Builder; }
-  LLVMContext& getLLVMContext() { return Session.getLLVMContext(); }
-  Function* getPrototype(const std::string &Name);
-
-  std::map<std::string, AllocaInst*> NamedValues;
-
-private:
-  SessionContext &Session;
-  std::unique_ptr<Module> M;
-  IRBuilder<> Builder;
-};
-
-Function* IRGenContext::getPrototype(const std::string &Name) {
-  if (Function *ExistingProto = M->getFunction(Name))
-    return ExistingProto;
-  if (PrototypeAST *ProtoAST = Session.getPrototypeAST(Name))
-    return ProtoAST->IRGen(*this);
-  return nullptr;
-}
-
-/// CreateEntryBlockAlloca - Create an alloca instruction in the entry block of
-/// the function.  This is used for mutable variables etc.
-static AllocaInst *CreateEntryBlockAlloca(Function *TheFunction,
-                                          const std::string &VarName) {
-  IRBuilder<> TmpB(&TheFunction->getEntryBlock(),
-                   TheFunction->getEntryBlock().begin());
-  return TmpB.CreateAlloca(Type::getDoubleTy(TheFunction->getContext()),
-                           nullptr, VarName);
-}
-
-Value *NumberExprAST::IRGen(IRGenContext &C) const {
-  return ConstantFP::get(C.getLLVMContext(), APFloat(Val));
-}
-
-Value *VariableExprAST::IRGen(IRGenContext &C) const {
-  // Look this variable up in the function.
-  Value *V = C.NamedValues[Name];
-
-  if (!V)
-    return ErrorP<Value>("Unknown variable name '" + Name + "'");
-
-  // Load the value.
-  return C.getBuilder().CreateLoad(V, Name.c_str());
-}
-
-Value *UnaryExprAST::IRGen(IRGenContext &C) const {
-  if (Value *OperandV = Operand->IRGen(C)) {
-    std::string FnName = MakeLegalFunctionName(std::string("unary")+Opcode);
-    if (Function *F = C.getPrototype(FnName))
-      return C.getBuilder().CreateCall(F, OperandV, "unop");
-    return ErrorP<Value>("Unknown unary operator");
-  }
-
-  // Could not codegen operand - return null.
-  return nullptr;
-}
-
-Value *BinaryExprAST::IRGen(IRGenContext &C) const {
-  // Special case '=' because we don't want to emit the LHS as an expression.
-  if (Op == '=') {
-    // Assignment requires the LHS to be an identifier.
-    auto &LHSVar = static_cast<VariableExprAST &>(*LHS);
-    // Codegen the RHS.
-    Value *Val = RHS->IRGen(C);
-    if (!Val) return nullptr;
-
-    // Look up the name.
-    if (auto Variable = C.NamedValues[LHSVar.Name]) {
-      C.getBuilder().CreateStore(Val, Variable);
-      return Val;
-    }
-    return ErrorP<Value>("Unknown variable name");
-  }
-
-  Value *L = LHS->IRGen(C);
-  Value *R = RHS->IRGen(C);
-  if (!L || !R) return nullptr;
-
-  switch (Op) {
-  case '+': return C.getBuilder().CreateFAdd(L, R, "addtmp");
-  case '-': return C.getBuilder().CreateFSub(L, R, "subtmp");
-  case '*': return C.getBuilder().CreateFMul(L, R, "multmp");
-  case '/': return C.getBuilder().CreateFDiv(L, R, "divtmp");
-  case '<':
-    L = C.getBuilder().CreateFCmpULT(L, R, "cmptmp");
-    // Convert bool 0/1 to double 0.0 or 1.0
-    return C.getBuilder().CreateUIToFP(L, Type::getDoubleTy(C.getLLVMContext()),
-                                       "booltmp");
-  default: break;
-  }
-
-  // If it wasn't a builtin binary operator, it must be a user defined one. Emit
-  // a call to it.
-  std::string FnName = MakeLegalFunctionName(std::string("binary")+Op);
-  if (Function *F = C.getPrototype(FnName)) {
-    Value *Ops[] = { L, R };
-    return C.getBuilder().CreateCall(F, Ops, "binop");
-  }
-
-  return ErrorP<Value>("Unknown binary operator");
-}
-
-Value *CallExprAST::IRGen(IRGenContext &C) const {
-  // Look up the name in the global module table.
-  if (auto CalleeF = C.getPrototype(CalleeName)) {
-    // If argument mismatch error.
-    if (CalleeF->arg_size() != Args.size())
-      return ErrorP<Value>("Incorrect # arguments passed");
-
-    std::vector<Value*> ArgsV;
-    for (unsigned i = 0, e = Args.size(); i != e; ++i) {
-      ArgsV.push_back(Args[i]->IRGen(C));
-      if (!ArgsV.back()) return nullptr;
-    }
-
-    return C.getBuilder().CreateCall(CalleeF, ArgsV, "calltmp");
-  }
-
-  return ErrorP<Value>("Unknown function referenced");
-}
-
-Value *IfExprAST::IRGen(IRGenContext &C) const {
-  Value *CondV = Cond->IRGen(C);
-  if (!CondV) return nullptr;
-
-  // Convert condition to a bool by comparing equal to 0.0.
-  ConstantFP *FPZero =
-    ConstantFP::get(C.getLLVMContext(), APFloat(0.0));
-  CondV = C.getBuilder().CreateFCmpONE(CondV, FPZero, "ifcond");
-
-  Function *TheFunction = C.getBuilder().GetInsertBlock()->getParent();
-
-  // Create blocks for the then and else cases.  Insert the 'then' block at the
-  // end of the function.
-  BasicBlock *ThenBB = BasicBlock::Create(C.getLLVMContext(), "then", TheFunction);
-  BasicBlock *ElseBB = BasicBlock::Create(C.getLLVMContext(), "else");
-  BasicBlock *MergeBB = BasicBlock::Create(C.getLLVMContext(), "ifcont");
-
-  C.getBuilder().CreateCondBr(CondV, ThenBB, ElseBB);
-
-  // Emit then value.
-  C.getBuilder().SetInsertPoint(ThenBB);
-
-  Value *ThenV = Then->IRGen(C);
-  if (!ThenV) return nullptr;
-
-  C.getBuilder().CreateBr(MergeBB);
-  // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
-  ThenBB = C.getBuilder().GetInsertBlock();
-
-  // Emit else block.
-  TheFunction->getBasicBlockList().push_back(ElseBB);
-  C.getBuilder().SetInsertPoint(ElseBB);
-
-  Value *ElseV = Else->IRGen(C);
-  if (!ElseV) return nullptr;
-
-  C.getBuilder().CreateBr(MergeBB);
-  // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
-  ElseBB = C.getBuilder().GetInsertBlock();
-
-  // Emit merge block.
-  TheFunction->getBasicBlockList().push_back(MergeBB);
-  C.getBuilder().SetInsertPoint(MergeBB);
-  PHINode *PN = C.getBuilder().CreatePHI(Type::getDoubleTy(C.getLLVMContext()),
-                                         2, "iftmp");
-
-  PN->addIncoming(ThenV, ThenBB);
-  PN->addIncoming(ElseV, ElseBB);
-  return PN;
-}
-
-Value *ForExprAST::IRGen(IRGenContext &C) const {
-  // Output this as:
-  //   var = alloca double
-  //   ...
-  //   start = startexpr
-  //   store start -> var
-  //   goto loop
-  // loop:
-  //   ...
-  //   bodyexpr
-  //   ...
-  // loopend:
-  //   step = stepexpr
-  //   endcond = endexpr
-  //
-  //   curvar = load var
-  //   nextvar = curvar + step
-  //   store nextvar -> var
-  //   br endcond, loop, endloop
-  // outloop:
-
-  Function *TheFunction = C.getBuilder().GetInsertBlock()->getParent();
-
-  // Create an alloca for the variable in the entry block.
-  AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
-
-  // Emit the start code first, without 'variable' in scope.
-  Value *StartVal = Start->IRGen(C);
-  if (!StartVal) return nullptr;
-
-  // Store the value into the alloca.
-  C.getBuilder().CreateStore(StartVal, Alloca);
-
-  // Make the new basic block for the loop header, inserting after current
-  // block.
-  BasicBlock *LoopBB =
-      BasicBlock::Create(C.getLLVMContext(), "loop", TheFunction);
-
-  // Insert an explicit fall through from the current block to the LoopBB.
-  C.getBuilder().CreateBr(LoopBB);
-
-  // Start insertion in LoopBB.
-  C.getBuilder().SetInsertPoint(LoopBB);
-
-  // Within the loop, the variable is defined equal to the PHI node.  If it
-  // shadows an existing variable, we have to restore it, so save it now.
-  AllocaInst *OldVal = C.NamedValues[VarName];
-  C.NamedValues[VarName] = Alloca;
-
-  // Emit the body of the loop.  This, like any other expr, can change the
-  // current BB.  Note that we ignore the value computed by the body, but don't
-  // allow an error.
-  if (!Body->IRGen(C))
-    return nullptr;
-
-  // Emit the step value.
-  Value *StepVal;
-  if (Step) {
-    StepVal = Step->IRGen(C);
-    if (!StepVal) return nullptr;
-  } else {
-    // If not specified, use 1.0.
-    StepVal = ConstantFP::get(C.getLLVMContext(), APFloat(1.0));
-  }
-
-  // Compute the end condition.
-  Value *EndCond = End->IRGen(C);
-  if (!EndCond) return nullptr;
-
-  // Reload, increment, and restore the alloca.  This handles the case where
-  // the body of the loop mutates the variable.
-  Value *CurVar = C.getBuilder().CreateLoad(Alloca, VarName.c_str());
-  Value *NextVar = C.getBuilder().CreateFAdd(CurVar, StepVal, "nextvar");
-  C.getBuilder().CreateStore(NextVar, Alloca);
-
-  // Convert condition to a bool by comparing equal to 0.0.
-  EndCond = C.getBuilder().CreateFCmpONE(
-      EndCond, ConstantFP::get(C.getLLVMContext(), APFloat(0.0)), "loopcond");
-
-  // Create the "after loop" block and insert it.
-  BasicBlock *AfterBB =
-      BasicBlock::Create(C.getLLVMContext(), "afterloop", TheFunction);
-
-  // Insert the conditional branch into the end of LoopEndBB.
-  C.getBuilder().CreateCondBr(EndCond, LoopBB, AfterBB);
-
-  // Any new code will be inserted in AfterBB.
-  C.getBuilder().SetInsertPoint(AfterBB);
-
-  // Restore the unshadowed variable.
-  if (OldVal)
-    C.NamedValues[VarName] = OldVal;
-  else
-    C.NamedValues.erase(VarName);
-
-  // for expr always returns 0.0.
-  return Constant::getNullValue(Type::getDoubleTy(C.getLLVMContext()));
-}
-
-Value *VarExprAST::IRGen(IRGenContext &C) const {
-  std::vector<AllocaInst *> OldBindings;
-
-  Function *TheFunction = C.getBuilder().GetInsertBlock()->getParent();
-
-  // Register all variables and emit their initializer.
-  for (unsigned i = 0, e = VarBindings.size(); i != e; ++i) {
-    auto &VarName = VarBindings[i].first;
-    auto &Init = VarBindings[i].second;
-
-    // Emit the initializer before adding the variable to scope, this prevents
-    // the initializer from referencing the variable itself, and permits stuff
-    // like this:
-    //  var a = 1 in
-    //    var a = a in ...   # refers to outer 'a'.
-    Value *InitVal;
-    if (Init) {
-      InitVal = Init->IRGen(C);
-      if (!InitVal) return nullptr;
-    } else // If not specified, use 0.0.
-      InitVal = ConstantFP::get(C.getLLVMContext(), APFloat(0.0));
-
-    AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
-    C.getBuilder().CreateStore(InitVal, Alloca);
-
-    // Remember the old variable binding so that we can restore the binding when
-    // we unrecurse.
-    OldBindings.push_back(C.NamedValues[VarName]);
-
-    // Remember this binding.
-    C.NamedValues[VarName] = Alloca;
-  }
-
-  // Codegen the body, now that all vars are in scope.
-  Value *BodyVal = Body->IRGen(C);
-  if (!BodyVal) return nullptr;
-
-  // Pop all our variables from scope.
-  for (unsigned i = 0, e = VarBindings.size(); i != e; ++i)
-    C.NamedValues[VarBindings[i].first] = OldBindings[i];
-
-  // Return the body computation.
-  return BodyVal;
-}
-
-Function *PrototypeAST::IRGen(IRGenContext &C) const {
-  std::string FnName = MakeLegalFunctionName(Name);
-
-  // Make the function type:  double(double,double) etc.
-  std::vector<Type *> Doubles(Args.size(),
-                              Type::getDoubleTy(C.getLLVMContext()));
-  FunctionType *FT =
-      FunctionType::get(Type::getDoubleTy(C.getLLVMContext()), Doubles, false);
-  Function *F = Function::Create(FT, Function::ExternalLinkage, FnName,
-                                 &C.getM());
-
-  // If F conflicted, there was already something named 'FnName'.  If it has a
-  // body, don't allow redefinition or reextern.
-  if (F->getName() != FnName) {
-    // Delete the one we just made and get the existing one.
-    F->eraseFromParent();
-    F = C.getM().getFunction(Name);
-
-    // If F already has a body, reject this.
-    if (!F->empty()) {
-      ErrorP<Function>("redefinition of function");
-      return nullptr;
-    }
-
-    // If F took a different number of args, reject.
-    if (F->arg_size() != Args.size()) {
-      ErrorP<Function>("redefinition of function with different # args");
-      return nullptr;
-    }
-  }
-
-  // Set names for all arguments.
-  unsigned Idx = 0;
-  for (Function::arg_iterator AI = F->arg_begin(); Idx != Args.size();
-       ++AI, ++Idx)
-    AI->setName(Args[Idx]);
-
-  return F;
-}
-
-/// CreateArgumentAllocas - Create an alloca for each argument and register the
-/// argument in the symbol table so that references to it will succeed.
-void PrototypeAST::CreateArgumentAllocas(Function *F, IRGenContext &C) {
-  Function::arg_iterator AI = F->arg_begin();
-  for (unsigned Idx = 0, e = Args.size(); Idx != e; ++Idx, ++AI) {
-    // Create an alloca for this variable.
-    AllocaInst *Alloca = CreateEntryBlockAlloca(F, Args[Idx]);
-
-    // Store the initial value into the alloca.
-    C.getBuilder().CreateStore(&*AI, Alloca);
-
-    // Add arguments to variable symbol table.
-    C.NamedValues[Args[Idx]] = Alloca;
-  }
-}
-
-Function *FunctionAST::IRGen(IRGenContext &C) const {
-  C.NamedValues.clear();
-
-  Function *TheFunction = Proto->IRGen(C);
-  if (!TheFunction)
-    return nullptr;
-
-  // If this is an operator, install it.
-  if (Proto->isBinaryOp())
-    BinopPrecedence[Proto->getOperatorName()] = Proto->Precedence;
-
-  // Create a new basic block to start insertion into.
-  BasicBlock *BB = BasicBlock::Create(C.getLLVMContext(), "entry", TheFunction);
-  C.getBuilder().SetInsertPoint(BB);
-
-  // Add all arguments to the symbol table and create their allocas.
-  Proto->CreateArgumentAllocas(TheFunction, C);
-
-  if (Value *RetVal = Body->IRGen(C)) {
-    // Finish off the function.
-    C.getBuilder().CreateRet(RetVal);
-
-    // Validate the generated code, checking for consistency.
-    verifyFunction(*TheFunction);
-
-    return TheFunction;
-  }
-
-  // Error reading body, remove function.
-  TheFunction->eraseFromParent();
-
-  if (Proto->isBinaryOp())
-    BinopPrecedence.erase(Proto->getOperatorName());
-  return nullptr;
-}
-
-//===----------------------------------------------------------------------===//
-// Top-Level parsing and JIT Driver
-//===----------------------------------------------------------------------===//
-
-static std::unique_ptr<llvm::Module> IRGen(SessionContext &S,
-                                           const FunctionAST &F) {
-  IRGenContext C(S);
-  auto LF = F.IRGen(C);
-  if (!LF)
-    return nullptr;
-#ifndef MINIMAL_STDERR_OUTPUT
-  fprintf(stderr, "Read function definition:");
-  LF->dump();
-#endif
-  return C.takeM();
-}
-
-template <typename T>
-static std::vector<T> singletonSet(T t) {
-  std::vector<T> Vec;
-  Vec.push_back(std::move(t));
-  return Vec;
-}
-
-class KaleidoscopeJIT {
-public:
-  typedef ObjectLinkingLayer<> ObjLayerT;
-  typedef IRCompileLayer<ObjLayerT> CompileLayerT;
-  typedef CompileLayerT::ModuleSetHandleT ModuleHandleT;
-
-  KaleidoscopeJIT(SessionContext &Session)
-      : DL(Session.getTarget().createDataLayout()),
-        CompileLayer(ObjectLayer, SimpleCompiler(Session.getTarget())) {}
-
-  std::string mangle(const std::string &Name) {
-    std::string MangledName;
-    {
-      raw_string_ostream MangledNameStream(MangledName);
-      Mangler::getNameWithPrefix(MangledNameStream, Name, DL);
-    }
-    return MangledName;
-  }
-
-  ModuleHandleT addModule(std::unique_ptr<Module> M) {
-    // We need a memory manager to allocate memory and resolve symbols for this
-    // new module. Create one that resolves symbols by looking back into the
-    // JIT.
-    auto Resolver = createLambdaResolver(
-                      [&](const std::string &Name) {
-                        if (auto Sym = findSymbol(Name))
-                          return RuntimeDyld::SymbolInfo(Sym.getAddress(),
-                                                         Sym.getFlags());
-                        return RuntimeDyld::SymbolInfo(nullptr);
-                      },
-                      [](const std::string &S) { return nullptr; }
-                    );
-    return CompileLayer.addModuleSet(singletonSet(std::move(M)),
-                                     make_unique<SectionMemoryManager>(),
-                                     std::move(Resolver));
-  }
-
-  void removeModule(ModuleHandleT H) { CompileLayer.removeModuleSet(H); }
-
-  JITSymbol findSymbol(const std::string &Name) {
-    return CompileLayer.findSymbol(Name, true);
-  }
-
-  JITSymbol findUnmangledSymbol(const std::string Name) {
-    return findSymbol(mangle(Name));
-  }
-
-private:
-  const DataLayout DL;
-  ObjLayerT ObjectLayer;
-  CompileLayerT CompileLayer;
-};
-
-static void HandleDefinition(SessionContext &S, KaleidoscopeJIT &J) {
-  if (auto F = ParseDefinition()) {
-    if (auto M = IRGen(S, *F)) {
-      S.addPrototypeAST(llvm::make_unique<PrototypeAST>(*F->Proto));
-      J.addModule(std::move(M));
-    }
-  } else {
-    // Skip token for error recovery.
-    getNextToken();
-  }
-}
-
-static void HandleExtern(SessionContext &S) {
-  if (auto P = ParseExtern())
-    S.addPrototypeAST(std::move(P));
-  else {
-    // Skip token for error recovery.
-    getNextToken();
-  }
-}
-
-static void HandleTopLevelExpression(SessionContext &S, KaleidoscopeJIT &J) {
-  // Evaluate a top-level expression into an anonymous function.
-  if (auto F = ParseTopLevelExpr()) {
-    IRGenContext C(S);
-    if (auto ExprFunc = F->IRGen(C)) {
-#ifndef MINIMAL_STDERR_OUTPUT
-      std::cerr << "Expression function:\n";
-      ExprFunc->dump();
-#endif
-      // Add the CodeGen'd module to the JIT. Keep a handle to it: We can remove
-      // this module as soon as we've executed Function ExprFunc.
-      auto H = J.addModule(C.takeM());
-
-      // Get the address of the JIT'd function in memory.
-      auto ExprSymbol = J.findUnmangledSymbol("__anon_expr");
-
-      // Cast it to the right type (takes no arguments, returns a double) so we
-      // can call it as a native function.
-      double (*FP)() = (double (*)())(intptr_t)ExprSymbol.getAddress();
-#ifdef MINIMAL_STDERR_OUTPUT
-      FP();
-#else
-      std::cerr << "Evaluated to " << FP() << "\n";
-#endif
-
-      // Remove the function.
-      J.removeModule(H);
-    }
-  } else {
-    // Skip token for error recovery.
-    getNextToken();
-  }
-}
-
-/// top ::= definition | external | expression | ';'
-static void MainLoop() {
-  LLVMContext TheContext;
-  SessionContext S(TheContext);
-  KaleidoscopeJIT J(S);
-
-  while (true) {
-    switch (CurTok) {
-    case tok_eof:    return;
-    case ';':        getNextToken(); continue;  // ignore top-level semicolons.
-    case tok_def:    HandleDefinition(S, J); break;
-    case tok_extern: HandleExtern(S); break;
-    default:         HandleTopLevelExpression(S, J); break;
-    }
-#ifndef MINIMAL_STDERR_OUTPUT
-    std::cerr << "ready> ";
-#endif
-  }
-}
-
-//===----------------------------------------------------------------------===//
-// "Library" functions that can be "extern'd" from user code.
-//===----------------------------------------------------------------------===//
-
-/// putchard - putchar that takes a double and returns 0.
-extern "C"
-double putchard(double X) {
-  putchar((char)X);
-  return 0;
-}
-
-/// printd - printf that takes a double prints it as "%f\n", returning 0.
-extern "C"
-double printd(double X) {
-  printf("%f", X);
-  return 0;
-}
-
-extern "C"
-double printlf() {
-  printf("\n");
-  return 0;
-}
-
-//===----------------------------------------------------------------------===//
-// Main driver code.
-//===----------------------------------------------------------------------===//
-
-int main() {
-  InitializeNativeTarget();
-  InitializeNativeTargetAsmPrinter();
-  InitializeNativeTargetAsmParser();
-
-  // Install standard binary operators.
-  // 1 is lowest precedence.
-  BinopPrecedence['='] = 2;
-  BinopPrecedence['<'] = 10;
-  BinopPrecedence['+'] = 20;
-  BinopPrecedence['-'] = 20;
-  BinopPrecedence['/'] = 40;
-  BinopPrecedence['*'] = 40;  // highest.
-
-  // Prime the first token.
-#ifndef MINIMAL_STDERR_OUTPUT
-  std::cerr << "ready> ";
-#endif
-  getNextToken();
-
-  std::cerr << std::fixed;
-
-  // Run the main "interpreter loop" now.
-  MainLoop();
-
-  return 0;
-}
diff --git a/examples/Kaleidoscope/Orc/lazy_codegen/CMakeLists.txt b/examples/Kaleidoscope/Orc/lazy_codegen/CMakeLists.txt
deleted file mode 100644
index faad3420c6a..00000000000
--- a/examples/Kaleidoscope/Orc/lazy_codegen/CMakeLists.txt
+++ /dev/null
@@ -1,12 +0,0 @@
-set(LLVM_LINK_COMPONENTS
-  Core
-  ExecutionEngine
-  Object
-  RuntimeDyld
-  Support
-  native
-  )
-
-add_kaleidoscope_chapter(Kaleidoscope-Orc-lazy_codegen
-  toy.cpp
-  )
diff --git a/examples/Kaleidoscope/Orc/lazy_codegen/README.txt b/examples/Kaleidoscope/Orc/lazy_codegen/README.txt
deleted file mode 100644
index 9d62a914327..00000000000
--- a/examples/Kaleidoscope/Orc/lazy_codegen/README.txt
+++ /dev/null
@@ -1,13 +0,0 @@
-//===----------------------------------------------------------------------===/
-//                 Kaleidoscope with Orc - Initial Version
-//===----------------------------------------------------------------------===//
-
-This version of Kaleidoscope with Orc demonstrates lazy code-generation.
-Unlike the first Kaleidoscope-Orc tutorial, where code-gen was performed as soon
-as modules were added to the JIT, this tutorial adds a LazyEmittingLayer to defer
-code-generation until modules are actually referenced. All IR-generation is still
-performed up-front.
-
-This directory contain a Makefile that allow the code to be built in a
-standalone manner, independent of the larger LLVM build infrastructure. To build
-the program you will need to have 'clang++' and 'llvm-config' in your path.
diff --git a/examples/Kaleidoscope/Orc/lazy_codegen/toy.cpp b/examples/Kaleidoscope/Orc/lazy_codegen/toy.cpp
deleted file mode 100644
index b71733c2dc8..00000000000
--- a/examples/Kaleidoscope/Orc/lazy_codegen/toy.cpp
+++ /dev/null
@@ -1,1361 +0,0 @@
-#include "llvm/ADT/APFloat.h"
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ExecutionEngine/ExecutionEngine.h"
-#include "llvm/ExecutionEngine/RuntimeDyld.h"
-#include "llvm/ExecutionEngine/SectionMemoryManager.h"
-#include "llvm/ExecutionEngine/Orc/CompileUtils.h"
-#include "llvm/ExecutionEngine/Orc/IRCompileLayer.h"
-#include "llvm/ExecutionEngine/Orc/JITSymbol.h"
-#include "llvm/ExecutionEngine/Orc/LambdaResolver.h"
-#include "llvm/ExecutionEngine/Orc/LazyEmittingLayer.h"
-#include "llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h"
-#include "llvm/IR/BasicBlock.h"
-#include "llvm/IR/Constant.h"
-#include "llvm/IR/Constants.h"
-#include "llvm/IR/DataLayout.h"
-#include "llvm/IR/DerivedTypes.h"
-#include "llvm/IR/Function.h"
-#include "llvm/IR/Instructions.h"
-#include "llvm/IR/IRBuilder.h"
-#include "llvm/IR/LLVMContext.h"
-#include "llvm/IR/Mangler.h"
-#include "llvm/IR/Module.h"
-#include "llvm/IR/Type.h"
-#include "llvm/IR/Verifier.h"
-#include "llvm/Support/raw_ostream.h"
-#include "llvm/Support/TargetSelect.h"
-#include "llvm/Target/TargetMachine.h"
-#include <cassert>
-#include <cctype>
-#include <cstdint>
-#include <cstdio>
-#include <cstdlib>
-#include <iomanip>
-#include <iostream>
-#include <map>
-#include <memory>
-#include <sstream>
-#include <string>
-#include <utility>
-#include <vector>
-
-using namespace llvm;
-using namespace llvm::orc;
-
-//===----------------------------------------------------------------------===//
-// Lexer
-//===----------------------------------------------------------------------===//
-
-// The lexer returns tokens [0-255] if it is an unknown character, otherwise one
-// of these for known things.
-enum Token {
-  tok_eof = -1,
-
-  // commands
-  tok_def = -2, tok_extern = -3,
-
-  // primary
-  tok_identifier = -4, tok_number = -5,
-
-  // control
-  tok_if = -6, tok_then = -7, tok_else = -8,
-  tok_for = -9, tok_in = -10,
-
-  // operators
-  tok_binary = -11, tok_unary = -12,
-
-  // var definition
-  tok_var = -13
-};
-
-static std::string IdentifierStr;  // Filled in if tok_identifier
-static double NumVal;              // Filled in if tok_number
-
-/// gettok - Return the next token from standard input.
-static int gettok() {
-  static int LastChar = ' ';
-
-  // Skip any whitespace.
-  while (isspace(LastChar))
-    LastChar = getchar();
-
-  if (isalpha(LastChar)) { // identifier: [a-zA-Z][a-zA-Z0-9]*
-    IdentifierStr = LastChar;
-    while (isalnum((LastChar = getchar())))
-      IdentifierStr += LastChar;
-
-    if (IdentifierStr == "def") return tok_def;
-    if (IdentifierStr == "extern") return tok_extern;
-    if (IdentifierStr == "if") return tok_if;
-    if (IdentifierStr == "then") return tok_then;
-    if (IdentifierStr == "else") return tok_else;
-    if (IdentifierStr == "for") return tok_for;
-    if (IdentifierStr == "in") return tok_in;
-    if (IdentifierStr == "binary") return tok_binary;
-    if (IdentifierStr == "unary") return tok_unary;
-    if (IdentifierStr == "var") return tok_var;
-    return tok_identifier;
-  }
-
-  if (isdigit(LastChar) || LastChar == '.') {   // Number: [0-9.]+
-    std::string NumStr;
-    do {
-      NumStr += LastChar;
-      LastChar = getchar();
-    } while (isdigit(LastChar) || LastChar == '.');
-
-    NumVal = strtod(NumStr.c_str(), nullptr);
-    return tok_number;
-  }
-
-  if (LastChar == '#') {
-    // Comment until end of line.
-    do LastChar = getchar();
-    while (LastChar != EOF && LastChar != '\n' && LastChar != '\r');
-
-    if (LastChar != EOF)
-      return gettok();
-  }
-
-  // Check for end of file.  Don't eat the EOF.
-  if (LastChar == EOF)
-    return tok_eof;
-
-  // Otherwise, just return the character as its ascii value.
-  int ThisChar = LastChar;
-  LastChar = getchar();
-  return ThisChar;
-}
-
-//===----------------------------------------------------------------------===//
-// Abstract Syntax Tree (aka Parse Tree)
-//===----------------------------------------------------------------------===//
-
-class IRGenContext;
-
-/// ExprAST - Base class for all expression nodes.
-struct ExprAST {
-  virtual ~ExprAST() {}
-  virtual Value *IRGen(IRGenContext &C) const = 0;
-};
-
-/// NumberExprAST - Expression class for numeric literals like "1.0".
-struct NumberExprAST : public ExprAST {
-  NumberExprAST(double Val) : Val(Val) {}
-  Value *IRGen(IRGenContext &C) const override;
-
-  double Val;
-};
-
-/// VariableExprAST - Expression class for referencing a variable, like "a".
-struct VariableExprAST : public ExprAST {
-  VariableExprAST(std::string Name) : Name(std::move(Name)) {}
-  Value *IRGen(IRGenContext &C) const override;
-
-  std::string Name;
-};
-
-/// UnaryExprAST - Expression class for a unary operator.
-struct UnaryExprAST : public ExprAST {
-  UnaryExprAST(char Opcode, std::unique_ptr<ExprAST> Operand)
-    : Opcode(std::move(Opcode)), Operand(std::move(Operand)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  char Opcode;
-  std::unique_ptr<ExprAST> Operand;
-};
-
-/// BinaryExprAST - Expression class for a binary operator.
-struct BinaryExprAST : public ExprAST {
-  BinaryExprAST(char Op, std::unique_ptr<ExprAST> LHS,
-                std::unique_ptr<ExprAST> RHS)
-    : Op(Op), LHS(std::move(LHS)), RHS(std::move(RHS)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  char Op;
-  std::unique_ptr<ExprAST> LHS, RHS;
-};
-
-/// CallExprAST - Expression class for function calls.
-struct CallExprAST : public ExprAST {
-  CallExprAST(std::string CalleeName,
-              std::vector<std::unique_ptr<ExprAST>> Args)
-    : CalleeName(std::move(CalleeName)), Args(std::move(Args)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  std::string CalleeName;
-  std::vector<std::unique_ptr<ExprAST>> Args;
-};
-
-/// IfExprAST - Expression class for if/then/else.
-struct IfExprAST : public ExprAST {
-  IfExprAST(std::unique_ptr<ExprAST> Cond, std::unique_ptr<ExprAST> Then,
-            std::unique_ptr<ExprAST> Else)
-    : Cond(std::move(Cond)), Then(std::move(Then)), Else(std::move(Else)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  std::unique_ptr<ExprAST> Cond, Then, Else;
-};
-
-/// ForExprAST - Expression class for for/in.
-struct ForExprAST : public ExprAST {
-  ForExprAST(std::string VarName, std::unique_ptr<ExprAST> Start,
-             std::unique_ptr<ExprAST> End, std::unique_ptr<ExprAST> Step,
-             std::unique_ptr<ExprAST> Body)
-    : VarName(std::move(VarName)), Start(std::move(Start)), End(std::move(End)),
-      Step(std::move(Step)), Body(std::move(Body)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  std::string VarName;
-  std::unique_ptr<ExprAST> Start, End, Step, Body;
-};
-
-/// VarExprAST - Expression class for var/in
-struct VarExprAST : public ExprAST {
-  typedef std::pair<std::string, std::unique_ptr<ExprAST>> Binding;
-  typedef std::vector<Binding> BindingList;
-
-  VarExprAST(BindingList VarBindings, std::unique_ptr<ExprAST> Body)
-    : VarBindings(std::move(VarBindings)), Body(std::move(Body)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  BindingList VarBindings;
-  std::unique_ptr<ExprAST> Body;
-};
-
-/// PrototypeAST - This class represents the "prototype" for a function,
-/// which captures its argument names as well as if it is an operator.
-struct PrototypeAST {
-  PrototypeAST(std::string Name, std::vector<std::string> Args,
-               bool IsOperator = false, unsigned Precedence = 0)
-    : Name(std::move(Name)), Args(std::move(Args)), IsOperator(IsOperator),
-      Precedence(Precedence) {}
-
-  Function *IRGen(IRGenContext &C) const;
-  void CreateArgumentAllocas(Function *F, IRGenContext &C);
-
-  bool isUnaryOp() const { return IsOperator && Args.size() == 1; }
-  bool isBinaryOp() const { return IsOperator && Args.size() == 2; }
-
-  char getOperatorName() const {
-    assert(isUnaryOp() || isBinaryOp());
-    return Name[Name.size()-1];
-  }
-
-  std::string Name;
-  std::vector<std::string> Args;
-  bool IsOperator;
-  unsigned Precedence;  // Precedence if a binary op.
-};
-
-/// FunctionAST - This class represents a function definition itself.
-struct FunctionAST {
-  FunctionAST(std::unique_ptr<PrototypeAST> Proto,
-              std::unique_ptr<ExprAST> Body)
-    : Proto(std::move(Proto)), Body(std::move(Body)) {}
-
-  Function *IRGen(IRGenContext &C) const;
-
-  std::unique_ptr<PrototypeAST> Proto;
-  std::unique_ptr<ExprAST> Body;
-};
-
-//===----------------------------------------------------------------------===//
-// Parser
-//===----------------------------------------------------------------------===//
-
-/// CurTok/getNextToken - Provide a simple token buffer.  CurTok is the current
-/// token the parser is looking at.  getNextToken reads another token from the
-/// lexer and updates CurTok with its results.
-static int CurTok;
-static int getNextToken() {
-  return CurTok = gettok();
-}
-
-/// BinopPrecedence - This holds the precedence for each binary operator that is
-/// defined.
-static std::map<char, int> BinopPrecedence;
-
-/// GetTokPrecedence - Get the precedence of the pending binary operator token.
-static int GetTokPrecedence() {
-  if (!isascii(CurTok))
-    return -1;
-
-  // Make sure it's a declared binop.
-  int TokPrec = BinopPrecedence[CurTok];
-  if (TokPrec <= 0) return -1;
-  return TokPrec;
-}
-
-template <typename T>
-std::unique_ptr<T> ErrorU(const std::string &Str) {
-  std::cerr << "Error: " << Str << "\n";
-  return nullptr;
-}
-
-template <typename T>
-T* ErrorP(const std::string &Str) {
-  std::cerr << "Error: " << Str << "\n";
-  return nullptr;
-}
-
-static std::unique_ptr<ExprAST> ParseExpression();
-
-/// identifierexpr
-///   ::= identifier
-///   ::= identifier '(' expression* ')'
-static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
-  std::string IdName = IdentifierStr;
-
-  getNextToken();  // eat identifier.
-
-  if (CurTok != '(') // Simple variable ref.
-    return llvm::make_unique<VariableExprAST>(IdName);
-
-  // Call.
-  getNextToken();  // eat (
-  std::vector<std::unique_ptr<ExprAST>> Args;
-  if (CurTok != ')') {
-    while (true) {
-      auto Arg = ParseExpression();
-      if (!Arg) return nullptr;
-      Args.push_back(std::move(Arg));
-
-      if (CurTok == ')') break;
-
-      if (CurTok != ',')
-        return ErrorU<CallExprAST>("Expected ')' or ',' in argument list");
-      getNextToken();
-    }
-  }
-
-  // Eat the ')'.
-  getNextToken();
-
-  return llvm::make_unique<CallExprAST>(IdName, std::move(Args));
-}
-
-/// numberexpr ::= number
-static std::unique_ptr<NumberExprAST> ParseNumberExpr() {
-  auto Result = llvm::make_unique<NumberExprAST>(NumVal);
-  getNextToken(); // consume the number
-  return Result;
-}
-
-/// parenexpr ::= '(' expression ')'
-static std::unique_ptr<ExprAST> ParseParenExpr() {
-  getNextToken();  // eat (.
-  auto V = ParseExpression();
-  if (!V)
-    return nullptr;
-
-  if (CurTok != ')')
-    return ErrorU<ExprAST>("expected ')'");
-  getNextToken();  // eat ).
-  return V;
-}
-
-/// ifexpr ::= 'if' expression 'then' expression 'else' expression
-static std::unique_ptr<ExprAST> ParseIfExpr() {
-  getNextToken();  // eat the if.
-
-  // condition.
-  auto Cond = ParseExpression();
-  if (!Cond)
-    return nullptr;
-
-  if (CurTok != tok_then)
-    return ErrorU<ExprAST>("expected then");
-  getNextToken();  // eat the then
-
-  auto Then = ParseExpression();
-  if (!Then)
-    return nullptr;
-
-  if (CurTok != tok_else)
-    return ErrorU<ExprAST>("expected else");
-
-  getNextToken();
-
-  auto Else = ParseExpression();
-  if (!Else)
-    return nullptr;
-
-  return llvm::make_unique<IfExprAST>(std::move(Cond), std::move(Then),
-                                      std::move(Else));
-}
-
-/// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression
-static std::unique_ptr<ForExprAST> ParseForExpr() {
-  getNextToken();  // eat the for.
-
-  if (CurTok != tok_identifier)
-    return ErrorU<ForExprAST>("expected identifier after for");
-
-  std::string IdName = IdentifierStr;
-  getNextToken();  // eat identifier.
-
-  if (CurTok != '=')
-    return ErrorU<ForExprAST>("expected '=' after for");
-  getNextToken();  // eat '='.
-
-  auto Start = ParseExpression();
-  if (!Start)
-    return nullptr;
-  if (CurTok != ',')
-    return ErrorU<ForExprAST>("expected ',' after for start value");
-  getNextToken();
-
-  auto End = ParseExpression();
-  if (!End)
-    return nullptr;
-
-  // The step value is optional.
-  std::unique_ptr<ExprAST> Step;
-  if (CurTok == ',') {
-    getNextToken();
-    Step = ParseExpression();
-    if (!Step)
-      return nullptr;
-  }
-
-  if (CurTok != tok_in)
-    return ErrorU<ForExprAST>("expected 'in' after for");
-  getNextToken();  // eat 'in'.
-
-  auto Body = ParseExpression();
-  if (Body)
-    return nullptr;
-
-  return llvm::make_unique<ForExprAST>(IdName, std::move(Start), std::move(End),
-                                       std::move(Step), std::move(Body));
-}
-
-/// varexpr ::= 'var' identifier ('=' expression)?
-//                    (',' identifier ('=' expression)?)* 'in' expression
-static std::unique_ptr<VarExprAST> ParseVarExpr() {
-  getNextToken();  // eat the var.
-
-  VarExprAST::BindingList VarBindings;
-
-  // At least one variable name is required.
-  if (CurTok != tok_identifier)
-    return ErrorU<VarExprAST>("expected identifier after var");
-
-  while (true) {
-    std::string Name = IdentifierStr;
-    getNextToken();  // eat identifier.
-
-    // Read the optional initializer.
-    std::unique_ptr<ExprAST> Init;
-    if (CurTok == '=') {
-      getNextToken(); // eat the '='.
-
-      Init = ParseExpression();
-      if (!Init)
-        return nullptr;
-    }
-
-    VarBindings.push_back(VarExprAST::Binding(Name, std::move(Init)));
-
-    // End of var list, exit loop.
-    if (CurTok != ',') break;
-    getNextToken(); // eat the ','.
-
-    if (CurTok != tok_identifier)
-      return ErrorU<VarExprAST>("expected identifier list after var");
-  }
-
-  // At this point, we have to have 'in'.
-  if (CurTok != tok_in)
-    return ErrorU<VarExprAST>("expected 'in' keyword after 'var'");
-  getNextToken();  // eat 'in'.
-
-  auto Body = ParseExpression();
-  if (!Body)
-    return nullptr;
-
-  return llvm::make_unique<VarExprAST>(std::move(VarBindings), std::move(Body));
-}
-
-/// primary
-///   ::= identifierexpr
-///   ::= numberexpr
-///   ::= parenexpr
-///   ::= ifexpr
-///   ::= forexpr
-///   ::= varexpr
-static std::unique_ptr<ExprAST> ParsePrimary() {
-  switch (CurTok) {
-  default: return ErrorU<ExprAST>("unknown token when expecting an expression");
-  case tok_identifier: return ParseIdentifierExpr();
-  case tok_number:     return ParseNumberExpr();
-  case '(':            return ParseParenExpr();
-  case tok_if:         return ParseIfExpr();
-  case tok_for:        return ParseForExpr();
-  case tok_var:        return ParseVarExpr();
-  }
-}
-
-/// unary
-///   ::= primary
-///   ::= '!' unary
-static std::unique_ptr<ExprAST> ParseUnary() {
-  // If the current token is not an operator, it must be a primary expr.
-  if (!isascii(CurTok) || CurTok == '(' || CurTok == ',')
-    return ParsePrimary();
-
-  // If this is a unary operator, read it.
-  int Opc = CurTok;
-  getNextToken();
-  if (auto Operand = ParseUnary())
-    return llvm::make_unique<UnaryExprAST>(Opc, std::move(Operand));
-  return nullptr;
-}
-
-/// binoprhs
-///   ::= ('+' unary)*
-static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec,
-                                              std::unique_ptr<ExprAST> LHS) {
-  // If this is a binop, find its precedence.
-  while (true) {
-    int TokPrec = GetTokPrecedence();
-
-    // If this is a binop that binds at least as tightly as the current binop,
-    // consume it, otherwise we are done.
-    if (TokPrec < ExprPrec)
-      return LHS;
-
-    // Okay, we know this is a binop.
-    int BinOp = CurTok;
-    getNextToken();  // eat binop
-
-    // Parse the unary expression after the binary operator.
-    auto RHS = ParseUnary();
-    if (!RHS)
-      return nullptr;
-
-    // If BinOp binds less tightly with RHS than the operator after RHS, let
-    // the pending operator take RHS as its LHS.
-    int NextPrec = GetTokPrecedence();
-    if (TokPrec < NextPrec) {
-      RHS = ParseBinOpRHS(TokPrec+1, std::move(RHS));
-      if (!RHS)
-        return nullptr;
-    }
-
-    // Merge LHS/RHS.
-    LHS = llvm::make_unique<BinaryExprAST>(BinOp, std::move(LHS), std::move(RHS));
-  }
-}
-
-/// expression
-///   ::= unary binoprhs
-///
-static std::unique_ptr<ExprAST> ParseExpression() {
-  auto LHS = ParseUnary();
-  if (!LHS)
-    return nullptr;
-
-  return ParseBinOpRHS(0, std::move(LHS));
-}
-
-/// prototype
-///   ::= id '(' id* ')'
-///   ::= binary LETTER number? (id, id)
-///   ::= unary LETTER (id)
-static std::unique_ptr<PrototypeAST> ParsePrototype() {
-  std::string FnName;
-
-  unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.
-  unsigned BinaryPrecedence = 30;
-
-  switch (CurTok) {
-  default:
-    return ErrorU<PrototypeAST>("Expected function name in prototype");
-  case tok_identifier:
-    FnName = IdentifierStr;
-    Kind = 0;
-    getNextToken();
-    break;
-  case tok_unary:
-    getNextToken();
-    if (!isascii(CurTok))
-      return ErrorU<PrototypeAST>("Expected unary operator");
-    FnName = "unary";
-    FnName += (char)CurTok;
-    Kind = 1;
-    getNextToken();
-    break;
-  case tok_binary:
-    getNextToken();
-    if (!isascii(CurTok))
-      return ErrorU<PrototypeAST>("Expected binary operator");
-    FnName = "binary";
-    FnName += (char)CurTok;
-    Kind = 2;
-    getNextToken();
-
-    // Read the precedence if present.
-    if (CurTok == tok_number) {
-      if (NumVal < 1 || NumVal > 100)
-        return ErrorU<PrototypeAST>("Invalid precedecnce: must be 1..100");
-      BinaryPrecedence = (unsigned)NumVal;
-      getNextToken();
-    }
-    break;
-  }
-
-  if (CurTok != '(')
-    return ErrorU<PrototypeAST>("Expected '(' in prototype");
-
-  std::vector<std::string> ArgNames;
-  while (getNextToken() == tok_identifier)
-    ArgNames.push_back(IdentifierStr);
-  if (CurTok != ')')
-    return ErrorU<PrototypeAST>("Expected ')' in prototype");
-
-  // success.
-  getNextToken();  // eat ')'.
-
-  // Verify right number of names for operator.
-  if (Kind && ArgNames.size() != Kind)
-    return ErrorU<PrototypeAST>("Invalid number of operands for operator");
-
-  return llvm::make_unique<PrototypeAST>(FnName, std::move(ArgNames), Kind != 0,
-                                         BinaryPrecedence);
-}
-
-/// definition ::= 'def' prototype expression
-static std::unique_ptr<FunctionAST> ParseDefinition() {
-  getNextToken();  // eat def.
-  auto Proto = ParsePrototype();
-  if (!Proto)
-    return nullptr;
-
-  if (auto Body = ParseExpression())
-    return llvm::make_unique<FunctionAST>(std::move(Proto), std::move(Body));
-  return nullptr;
-}
-
-/// toplevelexpr ::= expression
-static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
-  if (auto E = ParseExpression()) {
-    // Make an anonymous proto.
-    auto Proto =
-      llvm::make_unique<PrototypeAST>("__anon_expr", std::vector<std::string>());
-    return llvm::make_unique<FunctionAST>(std::move(Proto), std::move(E));
-  }
-  return nullptr;
-}
-
-/// external ::= 'extern' prototype
-static std::unique_ptr<PrototypeAST> ParseExtern() {
-  getNextToken();  // eat extern.
-  return ParsePrototype();
-}
-
-//===----------------------------------------------------------------------===//
-// Code Generation
-//===----------------------------------------------------------------------===//
-
-// FIXME: Obviously we can do better than this
-std::string GenerateUniqueName(const std::string &Root) {
-  static int i = 0;
-  std::ostringstream NameStream;
-  NameStream << Root << ++i;
-  return NameStream.str();
-}
-
-std::string MakeLegalFunctionName(std::string Name)
-{
-  std::string NewName;
-  assert(!Name.empty() && "Base name must not be empty");
-
-  // Start with what we have
-  NewName = Name;
-
-  // Look for a numberic first character
-  if (NewName.find_first_of("0123456789") == 0) {
-    NewName.insert(0, 1, 'n');
-  }
-
-  // Replace illegal characters with their ASCII equivalent
-  std::string legal_elements = "_abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
-  size_t pos;
-  while ((pos = NewName.find_first_not_of(legal_elements)) != std::string::npos) {
-    std::ostringstream NumStream;
-    NumStream << (int)NewName.at(pos);
-    NewName = NewName.replace(pos, 1, NumStream.str());
-  }
-
-  return NewName;
-}
-
-class SessionContext {
-public:
-  SessionContext(LLVMContext &C)
-    : Context(C), TM(EngineBuilder().selectTarget()) {}
-  LLVMContext& getLLVMContext() const { return Context; }
-  TargetMachine& getTarget() { return *TM; }
-  void addPrototypeAST(std::unique_ptr<PrototypeAST> P);
-  PrototypeAST* getPrototypeAST(const std::string &Name);
-
-private:
-  typedef std::map<std::string, std::unique_ptr<PrototypeAST>> PrototypeMap;
-
-  LLVMContext &Context;
-  std::unique_ptr<TargetMachine> TM;
-
-  PrototypeMap Prototypes;
-};
-
-void SessionContext::addPrototypeAST(std::unique_ptr<PrototypeAST> P) {
-  Prototypes[P->Name] = std::move(P);
-}
-
-PrototypeAST* SessionContext::getPrototypeAST(const std::string &Name) {
-  PrototypeMap::iterator I = Prototypes.find(Name);
-  if (I != Prototypes.end())
-    return I->second.get();
-  return nullptr;
-}
-
-class IRGenContext {
-public:
-  IRGenContext(SessionContext &S)
-    : Session(S),
-      M(new Module(GenerateUniqueName("jit_module_"),
-                   Session.getLLVMContext())),
-      Builder(Session.getLLVMContext()) {
-    M->setDataLayout(Session.getTarget().createDataLayout());
-  }
-
-  SessionContext& getSession() { return Session; }
-  Module& getM() const { return *M; }
-  std::unique_ptr<Module> takeM() { return std::move(M); }
-  IRBuilder<>& getBuilder() { return Builder; }
-  LLVMContext& getLLVMContext() { return Session.getLLVMContext(); }
-  Function* getPrototype(const std::string &Name);
-
-  std::map<std::string, AllocaInst*> NamedValues;
-
-private:
-  SessionContext &Session;
-  std::unique_ptr<Module> M;
-  IRBuilder<> Builder;
-};
-
-Function* IRGenContext::getPrototype(const std::string &Name) {
-  if (Function *ExistingProto = M->getFunction(Name))
-    return ExistingProto;
-  if (PrototypeAST *ProtoAST = Session.getPrototypeAST(Name))
-    return ProtoAST->IRGen(*this);
-  return nullptr;
-}
-
-/// CreateEntryBlockAlloca - Create an alloca instruction in the entry block of
-/// the function.  This is used for mutable variables etc.
-static AllocaInst *CreateEntryBlockAlloca(Function *TheFunction,
-                                          const std::string &VarName) {
-  IRBuilder<> TmpB(&TheFunction->getEntryBlock(),
-                   TheFunction->getEntryBlock().begin());
-  return TmpB.CreateAlloca(Type::getDoubleTy(TheFunction->getContext()),
-                           nullptr, VarName);
-}
-
-Value *NumberExprAST::IRGen(IRGenContext &C) const {
-  return ConstantFP::get(C.getLLVMContext(), APFloat(Val));
-}
-
-Value *VariableExprAST::IRGen(IRGenContext &C) const {
-  // Look this variable up in the function.
-  Value *V = C.NamedValues[Name];
-
-  if (!V)
-    return ErrorP<Value>("Unknown variable name '" + Name + "'");
-
-  // Load the value.
-  return C.getBuilder().CreateLoad(V, Name.c_str());
-}
-
-Value *UnaryExprAST::IRGen(IRGenContext &C) const {
-  if (Value *OperandV = Operand->IRGen(C)) {
-    std::string FnName = MakeLegalFunctionName(std::string("unary")+Opcode);
-    if (Function *F = C.getPrototype(FnName))
-      return C.getBuilder().CreateCall(F, OperandV, "unop");
-    return ErrorP<Value>("Unknown unary operator");
-  }
-
-  // Could not codegen operand - return null.
-  return nullptr;
-}
-
-Value *BinaryExprAST::IRGen(IRGenContext &C) const {
-  // Special case '=' because we don't want to emit the LHS as an expression.
-  if (Op == '=') {
-    // Assignment requires the LHS to be an identifier.
-    auto &LHSVar = static_cast<VariableExprAST &>(*LHS);
-    // Codegen the RHS.
-    Value *Val = RHS->IRGen(C);
-    if (!Val) return nullptr;
-
-    // Look up the name.
-    if (auto Variable = C.NamedValues[LHSVar.Name]) {
-      C.getBuilder().CreateStore(Val, Variable);
-      return Val;
-    }
-    return ErrorP<Value>("Unknown variable name");
-  }
-
-  Value *L = LHS->IRGen(C);
-  Value *R = RHS->IRGen(C);
-  if (!L || !R) return nullptr;
-
-  switch (Op) {
-  case '+': return C.getBuilder().CreateFAdd(L, R, "addtmp");
-  case '-': return C.getBuilder().CreateFSub(L, R, "subtmp");
-  case '*': return C.getBuilder().CreateFMul(L, R, "multmp");
-  case '/': return C.getBuilder().CreateFDiv(L, R, "divtmp");
-  case '<':
-    L = C.getBuilder().CreateFCmpULT(L, R, "cmptmp");
-    // Convert bool 0/1 to double 0.0 or 1.0
-    return C.getBuilder().CreateUIToFP(L, Type::getDoubleTy(C.getLLVMContext()),
-                                       "booltmp");
-  default: break;
-  }
-
-  // If it wasn't a builtin binary operator, it must be a user defined one. Emit
-  // a call to it.
-  std::string FnName = MakeLegalFunctionName(std::string("binary")+Op);
-  if (Function *F = C.getPrototype(FnName)) {
-    Value *Ops[] = { L, R };
-    return C.getBuilder().CreateCall(F, Ops, "binop");
-  }
-
-  return ErrorP<Value>("Unknown binary operator");
-}
-
-Value *CallExprAST::IRGen(IRGenContext &C) const {
-  // Look up the name in the global module table.
-  if (auto CalleeF = C.getPrototype(CalleeName)) {
-    // If argument mismatch error.
-    if (CalleeF->arg_size() != Args.size())
-      return ErrorP<Value>("Incorrect # arguments passed");
-
-    std::vector<Value*> ArgsV;
-    for (unsigned i = 0, e = Args.size(); i != e; ++i) {
-      ArgsV.push_back(Args[i]->IRGen(C));
-      if (!ArgsV.back()) return nullptr;
-    }
-
-    return C.getBuilder().CreateCall(CalleeF, ArgsV, "calltmp");
-  }
-
-  return ErrorP<Value>("Unknown function referenced");
-}
-
-Value *IfExprAST::IRGen(IRGenContext &C) const {
-  Value *CondV = Cond->IRGen(C);
-  if (!CondV) return nullptr;
-
-  // Convert condition to a bool by comparing equal to 0.0.
-  ConstantFP *FPZero =
-    ConstantFP::get(C.getLLVMContext(), APFloat(0.0));
-  CondV = C.getBuilder().CreateFCmpONE(CondV, FPZero, "ifcond");
-
-  Function *TheFunction = C.getBuilder().GetInsertBlock()->getParent();
-
-  // Create blocks for the then and else cases.  Insert the 'then' block at the
-  // end of the function.
-  BasicBlock *ThenBB = BasicBlock::Create(C.getLLVMContext(), "then", TheFunction);
-  BasicBlock *ElseBB = BasicBlock::Create(C.getLLVMContext(), "else");
-  BasicBlock *MergeBB = BasicBlock::Create(C.getLLVMContext(), "ifcont");
-
-  C.getBuilder().CreateCondBr(CondV, ThenBB, ElseBB);
-
-  // Emit then value.
-  C.getBuilder().SetInsertPoint(ThenBB);
-
-  Value *ThenV = Then->IRGen(C);
-  if (!ThenV) return nullptr;
-
-  C.getBuilder().CreateBr(MergeBB);
-  // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
-  ThenBB = C.getBuilder().GetInsertBlock();
-
-  // Emit else block.
-  TheFunction->getBasicBlockList().push_back(ElseBB);
-  C.getBuilder().SetInsertPoint(ElseBB);
-
-  Value *ElseV = Else->IRGen(C);
-  if (!ElseV) return nullptr;
-
-  C.getBuilder().CreateBr(MergeBB);
-  // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
-  ElseBB = C.getBuilder().GetInsertBlock();
-
-  // Emit merge block.
-  TheFunction->getBasicBlockList().push_back(MergeBB);
-  C.getBuilder().SetInsertPoint(MergeBB);
-  PHINode *PN = C.getBuilder().CreatePHI(Type::getDoubleTy(C.getLLVMContext()),
-                                         2, "iftmp");
-
-  PN->addIncoming(ThenV, ThenBB);
-  PN->addIncoming(ElseV, ElseBB);
-  return PN;
-}
-
-Value *ForExprAST::IRGen(IRGenContext &C) const {
-  // Output this as:
-  //   var = alloca double
-  //   ...
-  //   start = startexpr
-  //   store start -> var
-  //   goto loop
-  // loop:
-  //   ...
-  //   bodyexpr
-  //   ...
-  // loopend:
-  //   step = stepexpr
-  //   endcond = endexpr
-  //
-  //   curvar = load var
-  //   nextvar = curvar + step
-  //   store nextvar -> var
-  //   br endcond, loop, endloop
-  // outloop:
-
-  Function *TheFunction = C.getBuilder().GetInsertBlock()->getParent();
-
-  // Create an alloca for the variable in the entry block.
-  AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
-
-  // Emit the start code first, without 'variable' in scope.
-  Value *StartVal = Start->IRGen(C);
-  if (!StartVal) return nullptr;
-
-  // Store the value into the alloca.
-  C.getBuilder().CreateStore(StartVal, Alloca);
-
-  // Make the new basic block for the loop header, inserting after current
-  // block.
-  BasicBlock *LoopBB =
-      BasicBlock::Create(C.getLLVMContext(), "loop", TheFunction);
-
-  // Insert an explicit fall through from the current block to the LoopBB.
-  C.getBuilder().CreateBr(LoopBB);
-
-  // Start insertion in LoopBB.
-  C.getBuilder().SetInsertPoint(LoopBB);
-
-  // Within the loop, the variable is defined equal to the PHI node.  If it
-  // shadows an existing variable, we have to restore it, so save it now.
-  AllocaInst *OldVal = C.NamedValues[VarName];
-  C.NamedValues[VarName] = Alloca;
-
-  // Emit the body of the loop.  This, like any other expr, can change the
-  // current BB.  Note that we ignore the value computed by the body, but don't
-  // allow an error.
-  if (!Body->IRGen(C))
-    return nullptr;
-
-  // Emit the step value.
-  Value *StepVal;
-  if (Step) {
-    StepVal = Step->IRGen(C);
-    if (!StepVal) return nullptr;
-  } else {
-    // If not specified, use 1.0.
-    StepVal = ConstantFP::get(C.getLLVMContext(), APFloat(1.0));
-  }
-
-  // Compute the end condition.
-  Value *EndCond = End->IRGen(C);
-  if (!EndCond) return nullptr;
-
-  // Reload, increment, and restore the alloca.  This handles the case where
-  // the body of the loop mutates the variable.
-  Value *CurVar = C.getBuilder().CreateLoad(Alloca, VarName.c_str());
-  Value *NextVar = C.getBuilder().CreateFAdd(CurVar, StepVal, "nextvar");
-  C.getBuilder().CreateStore(NextVar, Alloca);
-
-  // Convert condition to a bool by comparing equal to 0.0.
-  EndCond = C.getBuilder().CreateFCmpONE(
-      EndCond, ConstantFP::get(C.getLLVMContext(), APFloat(0.0)), "loopcond");
-
-  // Create the "after loop" block and insert it.
-  BasicBlock *AfterBB =
-      BasicBlock::Create(C.getLLVMContext(), "afterloop", TheFunction);
-
-  // Insert the conditional branch into the end of LoopEndBB.
-  C.getBuilder().CreateCondBr(EndCond, LoopBB, AfterBB);
-
-  // Any new code will be inserted in AfterBB.
-  C.getBuilder().SetInsertPoint(AfterBB);
-
-  // Restore the unshadowed variable.
-  if (OldVal)
-    C.NamedValues[VarName] = OldVal;
-  else
-    C.NamedValues.erase(VarName);
-
-  // for expr always returns 0.0.
-  return Constant::getNullValue(Type::getDoubleTy(C.getLLVMContext()));
-}
-
-Value *VarExprAST::IRGen(IRGenContext &C) const {
-  std::vector<AllocaInst *> OldBindings;
-
-  Function *TheFunction = C.getBuilder().GetInsertBlock()->getParent();
-
-  // Register all variables and emit their initializer.
-  for (unsigned i = 0, e = VarBindings.size(); i != e; ++i) {
-    auto &VarName = VarBindings[i].first;
-    auto &Init = VarBindings[i].second;
-
-    // Emit the initializer before adding the variable to scope, this prevents
-    // the initializer from referencing the variable itself, and permits stuff
-    // like this:
-    //  var a = 1 in
-    //    var a = a in ...   # refers to outer 'a'.
-    Value *InitVal;
-    if (Init) {
-      InitVal = Init->IRGen(C);
-      if (!InitVal) return nullptr;
-    } else // If not specified, use 0.0.
-      InitVal = ConstantFP::get(C.getLLVMContext(), APFloat(0.0));
-
-    AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
-    C.getBuilder().CreateStore(InitVal, Alloca);
-
-    // Remember the old variable binding so that we can restore the binding when
-    // we unrecurse.
-    OldBindings.push_back(C.NamedValues[VarName]);
-
-    // Remember this binding.
-    C.NamedValues[VarName] = Alloca;
-  }
-
-  // Codegen the body, now that all vars are in scope.
-  Value *BodyVal = Body->IRGen(C);
-  if (!BodyVal) return nullptr;
-
-  // Pop all our variables from scope.
-  for (unsigned i = 0, e = VarBindings.size(); i != e; ++i)
-    C.NamedValues[VarBindings[i].first] = OldBindings[i];
-
-  // Return the body computation.
-  return BodyVal;
-}
-
-Function *PrototypeAST::IRGen(IRGenContext &C) const {
-  std::string FnName = MakeLegalFunctionName(Name);
-
-  // Make the function type:  double(double,double) etc.
-  std::vector<Type *> Doubles(Args.size(),
-                              Type::getDoubleTy(C.getLLVMContext()));
-  FunctionType *FT =
-      FunctionType::get(Type::getDoubleTy(C.getLLVMContext()), Doubles, false);
-  Function *F = Function::Create(FT, Function::ExternalLinkage, FnName,
-                                 &C.getM());
-
-  // If F conflicted, there was already something named 'FnName'.  If it has a
-  // body, don't allow redefinition or reextern.
-  if (F->getName() != FnName) {
-    // Delete the one we just made and get the existing one.
-    F->eraseFromParent();
-    F = C.getM().getFunction(Name);
-
-    // If F already has a body, reject this.
-    if (!F->empty()) {
-      ErrorP<Function>("redefinition of function");
-      return nullptr;
-    }
-
-    // If F took a different number of args, reject.
-    if (F->arg_size() != Args.size()) {
-      ErrorP<Function>("redefinition of function with different # args");
-      return nullptr;
-    }
-  }
-
-  // Set names for all arguments.
-  unsigned Idx = 0;
-  for (Function::arg_iterator AI = F->arg_begin(); Idx != Args.size();
-       ++AI, ++Idx)
-    AI->setName(Args[Idx]);
-
-  return F;
-}
-
-/// CreateArgumentAllocas - Create an alloca for each argument and register the
-/// argument in the symbol table so that references to it will succeed.
-void PrototypeAST::CreateArgumentAllocas(Function *F, IRGenContext &C) {
-  Function::arg_iterator AI = F->arg_begin();
-  for (unsigned Idx = 0, e = Args.size(); Idx != e; ++Idx, ++AI) {
-    // Create an alloca for this variable.
-    AllocaInst *Alloca = CreateEntryBlockAlloca(F, Args[Idx]);
-
-    // Store the initial value into the alloca.
-    C.getBuilder().CreateStore(&*AI, Alloca);
-
-    // Add arguments to variable symbol table.
-    C.NamedValues[Args[Idx]] = Alloca;
-  }
-}
-
-Function *FunctionAST::IRGen(IRGenContext &C) const {
-  C.NamedValues.clear();
-
-  Function *TheFunction = Proto->IRGen(C);
-  if (!TheFunction)
-    return nullptr;
-
-  // If this is an operator, install it.
-  if (Proto->isBinaryOp())
-    BinopPrecedence[Proto->getOperatorName()] = Proto->Precedence;
-
-  // Create a new basic block to start insertion into.
-  BasicBlock *BB = BasicBlock::Create(C.getLLVMContext(), "entry", TheFunction);
-  C.getBuilder().SetInsertPoint(BB);
-
-  // Add all arguments to the symbol table and create their allocas.
-  Proto->CreateArgumentAllocas(TheFunction, C);
-
-  if (Value *RetVal = Body->IRGen(C)) {
-    // Finish off the function.
-    C.getBuilder().CreateRet(RetVal);
-
-    // Validate the generated code, checking for consistency.
-    verifyFunction(*TheFunction);
-
-    return TheFunction;
-  }
-
-  // Error reading body, remove function.
-  TheFunction->eraseFromParent();
-
-  if (Proto->isBinaryOp())
-    BinopPrecedence.erase(Proto->getOperatorName());
-  return nullptr;
-}
-
-//===----------------------------------------------------------------------===//
-// Top-Level parsing and JIT Driver
-//===----------------------------------------------------------------------===//
-
-static std::unique_ptr<llvm::Module> IRGen(SessionContext &S,
-                                           const FunctionAST &F) {
-  IRGenContext C(S);
-  auto LF = F.IRGen(C);
-  if (!LF)
-    return nullptr;
-#ifndef MINIMAL_STDERR_OUTPUT
-  fprintf(stderr, "Read function definition:");
-  LF->dump();
-#endif
-  return C.takeM();
-}
-
-template <typename T>
-static std::vector<T> singletonSet(T t) {
-  std::vector<T> Vec;
-  Vec.push_back(std::move(t));
-  return Vec;
-}
-
-class KaleidoscopeJIT {
-public:
-  typedef ObjectLinkingLayer<> ObjLayerT;
-  typedef IRCompileLayer<ObjLayerT> CompileLayerT;
-  typedef LazyEmittingLayer<CompileLayerT> LazyEmitLayerT;
-
-  typedef LazyEmitLayerT::ModuleSetHandleT ModuleHandleT;
-
-  KaleidoscopeJIT(SessionContext &Session)
-      : DL(Session.getTarget().createDataLayout()),
-        CompileLayer(ObjectLayer, SimpleCompiler(Session.getTarget())),
-        LazyEmitLayer(CompileLayer) {}
-
-  std::string mangle(const std::string &Name) {
-    std::string MangledName;
-    {
-      raw_string_ostream MangledNameStream(MangledName);
-      Mangler::getNameWithPrefix(MangledNameStream, Name, DL);
-    }
-    return MangledName;
-  }
-
-  ModuleHandleT addModule(std::unique_ptr<Module> M) {
-    // We need a memory manager to allocate memory and resolve symbols for this
-    // new module. Create one that resolves symbols by looking back into the
-    // JIT.
-    auto Resolver = createLambdaResolver(
-                      [&](const std::string &Name) {
-                        if (auto Sym = findSymbol(Name))
-                          return RuntimeDyld::SymbolInfo(Sym.getAddress(),
-                                                         Sym.getFlags());
-                        return RuntimeDyld::SymbolInfo(nullptr);
-                      },
-                      [](const std::string &S) { return nullptr; } );
-
-    return LazyEmitLayer.addModuleSet(singletonSet(std::move(M)),
-                                      make_unique<SectionMemoryManager>(),
-                                      std::move(Resolver));
-  }
-
-  void removeModule(ModuleHandleT H) { LazyEmitLayer.removeModuleSet(H); }
-
-  JITSymbol findSymbol(const std::string &Name) {
-    return LazyEmitLayer.findSymbol(Name, true);
-  }
-
-  JITSymbol findUnmangledSymbol(const std::string Name) {
-    return findSymbol(mangle(Name));
-  }
-
-private:
-  const DataLayout DL;
-  ObjLayerT ObjectLayer;
-  CompileLayerT CompileLayer;
-  LazyEmitLayerT LazyEmitLayer;
-};
-
-static void HandleDefinition(SessionContext &S, KaleidoscopeJIT &J) {
-  if (auto F = ParseDefinition()) {
-    if (auto M = IRGen(S, *F)) {
-      S.addPrototypeAST(llvm::make_unique<PrototypeAST>(*F->Proto));
-      J.addModule(std::move(M));
-    }
-  } else {
-    // Skip token for error recovery.
-    getNextToken();
-  }
-}
-
-static void HandleExtern(SessionContext &S) {
-  if (auto P = ParseExtern())
-    S.addPrototypeAST(std::move(P));
-  else {
-    // Skip token for error recovery.
-    getNextToken();
-  }
-}
-
-static void HandleTopLevelExpression(SessionContext &S, KaleidoscopeJIT &J) {
-  // Evaluate a top-level expression into an anonymous function.
-  if (auto F = ParseTopLevelExpr()) {
-    IRGenContext C(S);
-    if (auto ExprFunc = F->IRGen(C)) {
-#ifndef MINIMAL_STDERR_OUTPUT
-      std::cerr << "Expression function:\n";
-      ExprFunc->dump();
-#endif
-      // Add the CodeGen'd module to the JIT. Keep a handle to it: We can remove
-      // this module as soon as we've executed Function ExprFunc.
-      auto H = J.addModule(C.takeM());
-
-      // Get the address of the JIT'd function in memory.
-      auto ExprSymbol = J.findUnmangledSymbol("__anon_expr");
-
-      // Cast it to the right type (takes no arguments, returns a double) so we
-      // can call it as a native function.
-      double (*FP)() = (double (*)())(intptr_t)ExprSymbol.getAddress();
-#ifdef MINIMAL_STDERR_OUTPUT
-      FP();
-#else
-      std::cerr << "Evaluated to " << FP() << "\n";
-#endif
-
-      // Remove the function.
-      J.removeModule(H);
-    }
-  } else {
-    // Skip token for error recovery.
-    getNextToken();
-  }
-}
-
-/// top ::= definition | external | expression | ';'
-static void MainLoop() {
-  LLVMContext TheContext;
-  SessionContext S(TheContext);
-  KaleidoscopeJIT J(S);
-
-  while (true) {
-    switch (CurTok) {
-    case tok_eof:    return;
-    case ';':        getNextToken(); continue;  // ignore top-level semicolons.
-    case tok_def:    HandleDefinition(S, J); break;
-    case tok_extern: HandleExtern(S); break;
-    default:         HandleTopLevelExpression(S, J); break;
-    }
-#ifndef MINIMAL_STDERR_OUTPUT
-    std::cerr << "ready> ";
-#endif
-  }
-}
-
-//===----------------------------------------------------------------------===//
-// "Library" functions that can be "extern'd" from user code.
-//===----------------------------------------------------------------------===//
-
-/// putchard - putchar that takes a double and returns 0.
-extern "C"
-double putchard(double X) {
-  putchar((char)X);
-  return 0;
-}
-
-/// printd - printf that takes a double prints it as "%f\n", returning 0.
-extern "C"
-double printd(double X) {
-  printf("%f", X);
-  return 0;
-}
-
-extern "C"
-double printlf() {
-  printf("\n");
-  return 0;
-}
-
-//===----------------------------------------------------------------------===//
-// Main driver code.
-//===----------------------------------------------------------------------===//
-
-int main() {
-  InitializeNativeTarget();
-  InitializeNativeTargetAsmPrinter();
-  InitializeNativeTargetAsmParser();
-
-  // Install standard binary operators.
-  // 1 is lowest precedence.
-  BinopPrecedence['='] = 2;
-  BinopPrecedence['<'] = 10;
-  BinopPrecedence['+'] = 20;
-  BinopPrecedence['-'] = 20;
-  BinopPrecedence['/'] = 40;
-  BinopPrecedence['*'] = 40;  // highest.
-
-  // Prime the first token.
-#ifndef MINIMAL_STDERR_OUTPUT
-  std::cerr << "ready> ";
-#endif
-  getNextToken();
-
-  std::cerr << std::fixed;
-
-  // Run the main "interpreter loop" now.
-  MainLoop();
-
-  return 0;
-}
diff --git a/examples/Kaleidoscope/Orc/lazy_irgen/CMakeLists.txt b/examples/Kaleidoscope/Orc/lazy_irgen/CMakeLists.txt
deleted file mode 100644
index 44886818e0f..00000000000
--- a/examples/Kaleidoscope/Orc/lazy_irgen/CMakeLists.txt
+++ /dev/null
@@ -1,12 +0,0 @@
-set(LLVM_LINK_COMPONENTS
-  Core
-  ExecutionEngine
-  Object
-  RuntimeDyld
-  Support
-  native
-  )
-
-add_kaleidoscope_chapter(Kaleidoscope-Orc-lazy_irgen
-  toy.cpp
-  )
diff --git a/examples/Kaleidoscope/Orc/lazy_irgen/README.txt b/examples/Kaleidoscope/Orc/lazy_irgen/README.txt
deleted file mode 100644
index 9aaa431712d..00000000000
--- a/examples/Kaleidoscope/Orc/lazy_irgen/README.txt
+++ /dev/null
@@ -1,16 +0,0 @@
-//===----------------------------------------------------------------------===/
-//                 Kaleidoscope with Orc - Lazy IRGen Version
-//===----------------------------------------------------------------------===//
-
-This version of Kaleidoscope with Orc demonstrates lazy IR-generation.
-Building on the lazy-codegen version of the tutorial, this version reduces the
-amount of up-front work that must be done by lazily IRgen'ing ASTs. When a
-function definition is entered, its AST is added to a map of available
-definitions. No IRGen is performed at this point and nothing is added to the JIT.
-When attempting to resolve symbol addresses, the lambda in
-KaleidoscopeJIT::getSymbolAddress will scan the AST map and generate IR on the
-fly.
-
-This directory contains a Makefile that allows the code to be built in a
-standalone manner, independent of the larger LLVM build infrastructure. To build
-the program you will need to have 'clang++' and 'llvm-config' in your path.
diff --git a/examples/Kaleidoscope/Orc/lazy_irgen/toy.cpp b/examples/Kaleidoscope/Orc/lazy_irgen/toy.cpp
deleted file mode 100644
index 72bcd7b633c..00000000000
--- a/examples/Kaleidoscope/Orc/lazy_irgen/toy.cpp
+++ /dev/null
@@ -1,1390 +0,0 @@
-#include "llvm/ADT/APFloat.h"
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ExecutionEngine/ExecutionEngine.h"
-#include "llvm/ExecutionEngine/RuntimeDyld.h"
-#include "llvm/ExecutionEngine/SectionMemoryManager.h"
-#include "llvm/ExecutionEngine/Orc/CompileUtils.h"
-#include "llvm/ExecutionEngine/Orc/IRCompileLayer.h"
-#include "llvm/ExecutionEngine/Orc/JITSymbol.h"
-#include "llvm/ExecutionEngine/Orc/LambdaResolver.h"
-#include "llvm/ExecutionEngine/Orc/LazyEmittingLayer.h"
-#include "llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h"
-#include "llvm/IR/BasicBlock.h"
-#include "llvm/IR/Constant.h"
-#include "llvm/IR/Constants.h"
-#include "llvm/IR/DerivedTypes.h"
-#include "llvm/IR/Function.h"
-#include "llvm/IR/Instructions.h"
-#include "llvm/IR/IRBuilder.h"
-#include "llvm/IR/LLVMContext.h"
-#include "llvm/IR/Mangler.h"
-#include "llvm/IR/Module.h"
-#include "llvm/IR/Type.h"
-#include "llvm/IR/Verifier.h"
-#include "llvm/Support/raw_ostream.h"
-#include "llvm/Support/TargetSelect.h"
-#include "llvm/Target/TargetMachine.h"
-#include <cassert>
-#include <cctype>
-#include <cstdint>
-#include <cstdio>
-#include <cstdlib>
-#include <iomanip>
-#include <iostream>
-#include <map>
-#include <memory>
-#include <sstream>
-#include <string>
-#include <utility>
-#include <vector>
-
-using namespace llvm;
-using namespace llvm::orc;
-
-//===----------------------------------------------------------------------===//
-// Lexer
-//===----------------------------------------------------------------------===//
-
-// The lexer returns tokens [0-255] if it is an unknown character, otherwise one
-// of these for known things.
-enum Token {
-  tok_eof = -1,
-
-  // commands
-  tok_def = -2, tok_extern = -3,
-
-  // primary
-  tok_identifier = -4, tok_number = -5,
-
-  // control
-  tok_if = -6, tok_then = -7, tok_else = -8,
-  tok_for = -9, tok_in = -10,
-
-  // operators
-  tok_binary = -11, tok_unary = -12,
-
-  // var definition
-  tok_var = -13
-};
-
-static std::string IdentifierStr;  // Filled in if tok_identifier
-static double NumVal;              // Filled in if tok_number
-
-/// gettok - Return the next token from standard input.
-static int gettok() {
-  static int LastChar = ' ';
-
-  // Skip any whitespace.
-  while (isspace(LastChar))
-    LastChar = getchar();
-
-  if (isalpha(LastChar)) { // identifier: [a-zA-Z][a-zA-Z0-9]*
-    IdentifierStr = LastChar;
-    while (isalnum((LastChar = getchar())))
-      IdentifierStr += LastChar;
-
-    if (IdentifierStr == "def") return tok_def;
-    if (IdentifierStr == "extern") return tok_extern;
-    if (IdentifierStr == "if") return tok_if;
-    if (IdentifierStr == "then") return tok_then;
-    if (IdentifierStr == "else") return tok_else;
-    if (IdentifierStr == "for") return tok_for;
-    if (IdentifierStr == "in") return tok_in;
-    if (IdentifierStr == "binary") return tok_binary;
-    if (IdentifierStr == "unary") return tok_unary;
-    if (IdentifierStr == "var") return tok_var;
-    return tok_identifier;
-  }
-
-  if (isdigit(LastChar) || LastChar == '.') {   // Number: [0-9.]+
-    std::string NumStr;
-    do {
-      NumStr += LastChar;
-      LastChar = getchar();
-    } while (isdigit(LastChar) || LastChar == '.');
-
-    NumVal = strtod(NumStr.c_str(), nullptr);
-    return tok_number;
-  }
-
-  if (LastChar == '#') {
-    // Comment until end of line.
-    do LastChar = getchar();
-    while (LastChar != EOF && LastChar != '\n' && LastChar != '\r');
-
-    if (LastChar != EOF)
-      return gettok();
-  }
-
-  // Check for end of file.  Don't eat the EOF.
-  if (LastChar == EOF)
-    return tok_eof;
-
-  // Otherwise, just return the character as its ascii value.
-  int ThisChar = LastChar;
-  LastChar = getchar();
-  return ThisChar;
-}
-
-//===----------------------------------------------------------------------===//
-// Abstract Syntax Tree (aka Parse Tree)
-//===----------------------------------------------------------------------===//
-
-class IRGenContext;
-
-/// ExprAST - Base class for all expression nodes.
-struct ExprAST {
-  virtual ~ExprAST() {}
-  virtual Value *IRGen(IRGenContext &C) const = 0;
-};
-
-/// NumberExprAST - Expression class for numeric literals like "1.0".
-struct NumberExprAST : public ExprAST {
-  NumberExprAST(double Val) : Val(Val) {}
-  Value *IRGen(IRGenContext &C) const override;
-
-  double Val;
-};
-
-/// VariableExprAST - Expression class for referencing a variable, like "a".
-struct VariableExprAST : public ExprAST {
-  VariableExprAST(std::string Name) : Name(std::move(Name)) {}
-  Value *IRGen(IRGenContext &C) const override;
-
-  std::string Name;
-};
-
-/// UnaryExprAST - Expression class for a unary operator.
-struct UnaryExprAST : public ExprAST {
-  UnaryExprAST(char Opcode, std::unique_ptr<ExprAST> Operand)
-    : Opcode(std::move(Opcode)), Operand(std::move(Operand)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  char Opcode;
-  std::unique_ptr<ExprAST> Operand;
-};
-
-/// BinaryExprAST - Expression class for a binary operator.
-struct BinaryExprAST : public ExprAST {
-  BinaryExprAST(char Op, std::unique_ptr<ExprAST> LHS,
-                std::unique_ptr<ExprAST> RHS)
-    : Op(Op), LHS(std::move(LHS)), RHS(std::move(RHS)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  char Op;
-  std::unique_ptr<ExprAST> LHS, RHS;
-};
-
-/// CallExprAST - Expression class for function calls.
-struct CallExprAST : public ExprAST {
-  CallExprAST(std::string CalleeName,
-              std::vector<std::unique_ptr<ExprAST>> Args)
-    : CalleeName(std::move(CalleeName)), Args(std::move(Args)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  std::string CalleeName;
-  std::vector<std::unique_ptr<ExprAST>> Args;
-};
-
-/// IfExprAST - Expression class for if/then/else.
-struct IfExprAST : public ExprAST {
-  IfExprAST(std::unique_ptr<ExprAST> Cond, std::unique_ptr<ExprAST> Then,
-            std::unique_ptr<ExprAST> Else)
-    : Cond(std::move(Cond)), Then(std::move(Then)), Else(std::move(Else)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  std::unique_ptr<ExprAST> Cond, Then, Else;
-};
-
-/// ForExprAST - Expression class for for/in.
-struct ForExprAST : public ExprAST {
-  ForExprAST(std::string VarName, std::unique_ptr<ExprAST> Start,
-             std::unique_ptr<ExprAST> End, std::unique_ptr<ExprAST> Step,
-             std::unique_ptr<ExprAST> Body)
-    : VarName(std::move(VarName)), Start(std::move(Start)), End(std::move(End)),
-      Step(std::move(Step)), Body(std::move(Body)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  std::string VarName;
-  std::unique_ptr<ExprAST> Start, End, Step, Body;
-};
-
-/// VarExprAST - Expression class for var/in
-struct VarExprAST : public ExprAST {
-  typedef std::pair<std::string, std::unique_ptr<ExprAST>> Binding;
-  typedef std::vector<Binding> BindingList;
-
-  VarExprAST(BindingList VarBindings, std::unique_ptr<ExprAST> Body)
-    : VarBindings(std::move(VarBindings)), Body(std::move(Body)) {}
-
-  Value *IRGen(IRGenContext &C) const override;
-
-  BindingList VarBindings;
-  std::unique_ptr<ExprAST> Body;
-};
-
-/// PrototypeAST - This class represents the "prototype" for a function,
-/// which captures its argument names as well as if it is an operator.
-struct PrototypeAST {
-  PrototypeAST(std::string Name, std::vector<std::string> Args,
-               bool IsOperator = false, unsigned Precedence = 0)
-    : Name(std::move(Name)), Args(std::move(Args)), IsOperator(IsOperator),
-      Precedence(Precedence) {}
-
-  Function *IRGen(IRGenContext &C) const;
-  void CreateArgumentAllocas(Function *F, IRGenContext &C);
-
-  bool isUnaryOp() const { return IsOperator && Args.size() == 1; }
-  bool isBinaryOp() const { return IsOperator && Args.size() == 2; }
-
-  char getOperatorName() const {
-    assert(isUnaryOp() || isBinaryOp());
-    return Name[Name.size()-1];
-  }
-
-  std::string Name;
-  std::vector<std::string> Args;
-  bool IsOperator;
-  unsigned Precedence;  // Precedence if a binary op.
-};
-
-/// FunctionAST - This class represents a function definition itself.
-struct FunctionAST {
-  FunctionAST(std::unique_ptr<PrototypeAST> Proto,
-              std::unique_ptr<ExprAST> Body)
-    : Proto(std::move(Proto)), Body(std::move(Body)) {}
-
-  Function *IRGen(IRGenContext &C) const;
-
-  std::unique_ptr<PrototypeAST> Proto;
-  std::unique_ptr<ExprAST> Body;
-};
-
-//===----------------------------------------------------------------------===//
-// Parser
-//===----------------------------------------------------------------------===//
-
-/// CurTok/getNextToken - Provide a simple token buffer.  CurTok is the current
-/// token the parser is looking at.  getNextToken reads another token from the
-/// lexer and updates CurTok with its results.
-static int CurTok;
-static int getNextToken() {
-  return CurTok = gettok();
-}
-
-/// BinopPrecedence - This holds the precedence for each binary operator that is
-/// defined.
-static std::map<char, int> BinopPrecedence;
-
-/// GetTokPrecedence - Get the precedence of the pending binary operator token.
-static int GetTokPrecedence() {
-  if (!isascii(CurTok))
-    return -1;
-
-  // Make sure it's a declared binop.
-  int TokPrec = BinopPrecedence[CurTok];
-  if (TokPrec <= 0) return -1;
-  return TokPrec;
-}
-
-template <typename T>
-std::unique_ptr<T> ErrorU(const std::string &Str) {
-  std::cerr << "Error: " << Str << "\n";
-  return nullptr;
-}
-
-template <typename T>
-T* ErrorP(const std::string &Str) {
-  std::cerr << "Error: " << Str << "\n";
-  return nullptr;
-}
-
-static std::unique_ptr<ExprAST> ParseExpression();
-
-/// identifierexpr
-///   ::= identifier
-///   ::= identifier '(' expression* ')'
-static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
-  std::string IdName = IdentifierStr;
-
-  getNextToken();  // eat identifier.
-
-  if (CurTok != '(') // Simple variable ref.
-    return llvm::make_unique<VariableExprAST>(IdName);
-
-  // Call.
-  getNextToken();  // eat (
-  std::vector<std::unique_ptr<ExprAST>> Args;
-  if (CurTok != ')') {
-    while (true) {
-      auto Arg = ParseExpression();
-      if (!Arg) return nullptr;
-      Args.push_back(std::move(Arg));
-
-      if (CurTok == ')') break;
-
-      if (CurTok != ',')
-        return ErrorU<CallExprAST>("Expected ')' or ',' in argument list");
-      getNextToken();
-    }
-  }
-
-  // Eat the ')'.
-  getNextToken();
-
-  return llvm::make_unique<CallExprAST>(IdName, std::move(Args));
-}
-
-/// numberexpr ::= number
-static std::unique_ptr<NumberExprAST> ParseNumberExpr() {
-  auto Result = llvm::make_unique<NumberExprAST>(NumVal);
-  getNextToken(); // consume the number
-  return Result;
-}
-
-/// parenexpr ::= '(' expression ')'
-static std::unique_ptr<ExprAST> ParseParenExpr() {
-  getNextToken();  // eat (.
-  auto V = ParseExpression();
-  if (!V)
-    return nullptr;
-
-  if (CurTok != ')')
-    return ErrorU<ExprAST>("expected ')'");
-  getNextToken();  // eat ).
-  return V;
-}
-
-/// ifexpr ::= 'if' expression 'then' expression 'else' expression
-static std::unique_ptr<ExprAST> ParseIfExpr() {
-  getNextToken();  // eat the if.
-
-  // condition.
-  auto Cond = ParseExpression();
-  if (!Cond)
-    return nullptr;
-
-  if (CurTok != tok_then)
-    return ErrorU<ExprAST>("expected then");
-  getNextToken();  // eat the then
-
-  auto Then = ParseExpression();
-  if (!Then)
-    return nullptr;
-
-  if (CurTok != tok_else)
-    return ErrorU<ExprAST>("expected else");
-
-  getNextToken();
-
-  auto Else = ParseExpression();
-  if (!Else)
-    return nullptr;
-
-  return llvm::make_unique<IfExprAST>(std::move(Cond), std::move(Then),
-                                      std::move(Else));
-}
-
-/// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression
-static std::unique_ptr<ForExprAST> ParseForExpr() {
-  getNextToken();  // eat the for.
-
-  if (CurTok != tok_identifier)
-    return ErrorU<ForExprAST>("expected identifier after for");
-
-  std::string IdName = IdentifierStr;
-  getNextToken();  // eat identifier.
-
-  if (CurTok != '=')
-    return ErrorU<ForExprAST>("expected '=' after for");
-  getNextToken();  // eat '='.
-
-  auto Start = ParseExpression();
-  if (!Start)
-    return nullptr;
-  if (CurTok != ',')
-    return ErrorU<ForExprAST>("expected ',' after for start value");
-  getNextToken();
-
-  auto End = ParseExpression();
-  if (!End)
-    return nullptr;
-
-  // The step value is optional.
-  std::unique_ptr<ExprAST> Step;
-  if (CurTok == ',') {
-    getNextToken();
-    Step = ParseExpression();
-    if (!Step)
-      return nullptr;
-  }
-
-  if (CurTok != tok_in)
-    return ErrorU<ForExprAST>("expected 'in' after for");
-  getNextToken();  // eat 'in'.
-
-  auto Body = ParseExpression();
-  if (Body)
-    return nullptr;
-
-  return llvm::make_unique<ForExprAST>(IdName, std::move(Start), std::move(End),
-                                       std::move(Step), std::move(Body));
-}
-
-/// varexpr ::= 'var' identifier ('=' expression)?
-//                    (',' identifier ('=' expression)?)* 'in' expression
-static std::unique_ptr<VarExprAST> ParseVarExpr() {
-  getNextToken();  // eat the var.
-
-  VarExprAST::BindingList VarBindings;
-
-  // At least one variable name is required.
-  if (CurTok != tok_identifier)
-    return ErrorU<VarExprAST>("expected identifier after var");
-
-  while (true) {
-    std::string Name = IdentifierStr;
-    getNextToken();  // eat identifier.
-
-    // Read the optional initializer.
-    std::unique_ptr<ExprAST> Init;
-    if (CurTok == '=') {
-      getNextToken(); // eat the '='.
-
-      Init = ParseExpression();
-      if (!Init)
-        return nullptr;
-    }
-
-    VarBindings.push_back(VarExprAST::Binding(Name, std::move(Init)));
-
-    // End of var list, exit loop.
-    if (CurTok != ',') break;
-    getNextToken(); // eat the ','.
-
-    if (CurTok != tok_identifier)
-      return ErrorU<VarExprAST>("expected identifier list after var");
-  }
-
-  // At this point, we have to have 'in'.
-  if (CurTok != tok_in)
-    return ErrorU<VarExprAST>("expected 'in' keyword after 'var'");
-  getNextToken();  // eat 'in'.
-
-  auto Body = ParseExpression();
-  if (!Body)
-    return nullptr;
-
-  return llvm::make_unique<VarExprAST>(std::move(VarBindings), std::move(Body));
-}
-
-/// primary
-///   ::= identifierexpr
-///   ::= numberexpr
-///   ::= parenexpr
-///   ::= ifexpr
-///   ::= forexpr
-///   ::= varexpr
-static std::unique_ptr<ExprAST> ParsePrimary() {
-  switch (CurTok) {
-  default: return ErrorU<ExprAST>("unknown token when expecting an expression");
-  case tok_identifier: return ParseIdentifierExpr();
-  case tok_number:     return ParseNumberExpr();
-  case '(':            return ParseParenExpr();
-  case tok_if:         return ParseIfExpr();
-  case tok_for:        return ParseForExpr();
-  case tok_var:        return ParseVarExpr();
-  }
-}
-
-/// unary
-///   ::= primary
-///   ::= '!' unary
-static std::unique_ptr<ExprAST> ParseUnary() {
-  // If the current token is not an operator, it must be a primary expr.
-  if (!isascii(CurTok) || CurTok == '(' || CurTok == ',')
-    return ParsePrimary();
-
-  // If this is a unary operator, read it.
-  int Opc = CurTok;
-  getNextToken();
-  if (auto Operand = ParseUnary())
-    return llvm::make_unique<UnaryExprAST>(Opc, std::move(Operand));
-  return nullptr;
-}
-
-/// binoprhs
-///   ::= ('+' unary)*
-static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec,
-                                              std::unique_ptr<ExprAST> LHS) {
-  // If this is a binop, find its precedence.
-  while (true) {
-    int TokPrec = GetTokPrecedence();
-
-    // If this is a binop that binds at least as tightly as the current binop,
-    // consume it, otherwise we are done.
-    if (TokPrec < ExprPrec)
-      return LHS;
-
-    // Okay, we know this is a binop.
-    int BinOp = CurTok;
-    getNextToken();  // eat binop
-
-    // Parse the unary expression after the binary operator.
-    auto RHS = ParseUnary();
-    if (!RHS)
-      return nullptr;
-
-    // If BinOp binds less tightly with RHS than the operator after RHS, let
-    // the pending operator take RHS as its LHS.
-    int NextPrec = GetTokPrecedence();
-    if (TokPrec < NextPrec) {
-      RHS = ParseBinOpRHS(TokPrec+1, std::move(RHS));
-      if (!RHS)
-        return nullptr;
-    }
-
-    // Merge LHS/RHS.
-    LHS = llvm::make_unique<BinaryExprAST>(BinOp, std::move(LHS), std::move(RHS));
-  }
-}
-
-/// expression
-///   ::= unary binoprhs
-///
-static std::unique_ptr<ExprAST> ParseExpression() {
-  auto LHS = ParseUnary();
-  if (!LHS)
-    return nullptr;
-
-  return ParseBinOpRHS(0, std::move(LHS));
-}
-
-/// prototype
-///   ::= id '(' id* ')'
-///   ::= binary LETTER number? (id, id)
-///   ::= unary LETTER (id)
-static std::unique_ptr<PrototypeAST> ParsePrototype() {
-  std::string FnName;
-
-  unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.
-  unsigned BinaryPrecedence = 30;
-
-  switch (CurTok) {
-  default:
-    return ErrorU<PrototypeAST>("Expected function name in prototype");
-  case tok_identifier:
-    FnName = IdentifierStr;
-    Kind = 0;
-    getNextToken();
-    break;
-  case tok_unary:
-    getNextToken();
-    if (!isascii(CurTok))
-      return ErrorU<PrototypeAST>("Expected unary operator");
-    FnName = "unary";
-    FnName += (char)CurTok;
-    Kind = 1;
-    getNextToken();
-    break;
-  case tok_binary:
-    getNextToken();
-    if (!isascii(CurTok))
-      return ErrorU<PrototypeAST>("Expected binary operator");
-    FnName = "binary";
-    FnName += (char)CurTok;
-    Kind = 2;
-    getNextToken();
-
-    // Read the precedence if present.
-    if (CurTok == tok_number) {
-      if (NumVal < 1 || NumVal > 100)
-        return ErrorU<PrototypeAST>("Invalid precedecnce: must be 1..100");
-      BinaryPrecedence = (unsigned)NumVal;
-      getNextToken();
-    }
-    break;
-  }
-
-  if (CurTok != '(')
-    return ErrorU<PrototypeAST>("Expected '(' in prototype");
-
-  std::vector<std::string> ArgNames;
-  while (getNextToken() == tok_identifier)
-    ArgNames.push_back(IdentifierStr);
-  if (CurTok != ')')
-    return ErrorU<PrototypeAST>("Expected ')' in prototype");
-
-  // success.
-  getNextToken();  // eat ')'.
-
-  // Verify right number of names for operator.
-  if (Kind && ArgNames.size() != Kind)
-    return ErrorU<PrototypeAST>("Invalid number of operands for operator");
-
-  return llvm::make_unique<PrototypeAST>(FnName, std::move(ArgNames), Kind != 0,
-                                         BinaryPrecedence);
-}
-
-/// definition ::= 'def' prototype expression
-static std::unique_ptr<FunctionAST> ParseDefinition() {
-  getNextToken();  // eat def.
-  auto Proto = ParsePrototype();
-  if (!Proto)
-    return nullptr;
-
-  if (auto Body = ParseExpression())
-    return llvm::make_unique<FunctionAST>(std::move(Proto), std::move(Body));
-  return nullptr;
-}
-
-/// toplevelexpr ::= expression
-static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
-  if (auto E = ParseExpression()) {
-    // Make an anonymous proto.
-    auto Proto =
-      llvm::make_unique<PrototypeAST>("__anon_expr", std::vector<std::string>());
-    return llvm::make_unique<FunctionAST>(std::move(Proto), std::move(E));
-  }
-  return nullptr;
-}
-
-/// external ::= 'extern' prototype
-static std::unique_ptr<PrototypeAST> ParseExtern() {
-  getNextToken();  // eat extern.
-  return ParsePrototype();
-}
-
-//===----------------------------------------------------------------------===//
-// Code Generation
-//===----------------------------------------------------------------------===//
-
-// FIXME: Obviously we can do better than this
-std::string GenerateUniqueName(const std::string &Root) {
-  static int i = 0;
-  std::ostringstream NameStream;
-  NameStream << Root << ++i;
-  return NameStream.str();
-}
-
-std::string MakeLegalFunctionName(std::string Name)
-{
-  std::string NewName;
-  assert(!Name.empty() && "Base name must not be empty");
-
-  // Start with what we have
-  NewName = Name;
-
-  // Look for a numberic first character
-  if (NewName.find_first_of("0123456789") == 0) {
-    NewName.insert(0, 1, 'n');
-  }
-
-  // Replace illegal characters with their ASCII equivalent
-  std::string legal_elements = "_abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
-  size_t pos;
-  while ((pos = NewName.find_first_not_of(legal_elements)) != std::string::npos) {
-    std::ostringstream NumStream;
-    NumStream << (int)NewName.at(pos);
-    NewName = NewName.replace(pos, 1, NumStream.str());
-  }
-
-  return NewName;
-}
-
-class SessionContext {
-public:
-  SessionContext(LLVMContext &C)
-    : Context(C), TM(EngineBuilder().selectTarget()) {}
-  LLVMContext& getLLVMContext() const { return Context; }
-  TargetMachine& getTarget() { return *TM; }
-  void addPrototypeAST(std::unique_ptr<PrototypeAST> P);
-  PrototypeAST* getPrototypeAST(const std::string &Name);
-
-private:
-  typedef std::map<std::string, std::unique_ptr<PrototypeAST>> PrototypeMap;
-
-  LLVMContext &Context;
-  std::unique_ptr<TargetMachine> TM;
-
-  PrototypeMap Prototypes;
-};
-
-void SessionContext::addPrototypeAST(std::unique_ptr<PrototypeAST> P) {
-  Prototypes[P->Name] = std::move(P);
-}
-
-PrototypeAST* SessionContext::getPrototypeAST(const std::string &Name) {
-  PrototypeMap::iterator I = Prototypes.find(Name);
-  if (I != Prototypes.end())
-    return I->second.get();
-  return nullptr;
-}
-
-class IRGenContext {
-public:
-  IRGenContext(SessionContext &S)
-    : Session(S),
-      M(new Module(GenerateUniqueName("jit_module_"),
-                   Session.getLLVMContext())),
-      Builder(Session.getLLVMContext()) {
-    M->setDataLayout(Session.getTarget().createDataLayout());
-  }
-
-  SessionContext& getSession() { return Session; }
-  Module& getM() const { return *M; }
-  std::unique_ptr<Module> takeM() { return std::move(M); }
-  IRBuilder<>& getBuilder() { return Builder; }
-  LLVMContext& getLLVMContext() { return Session.getLLVMContext(); }
-  Function* getPrototype(const std::string &Name);
-
-  std::map<std::string, AllocaInst*> NamedValues;
-
-private:
-  SessionContext &Session;
-  std::unique_ptr<Module> M;
-  IRBuilder<> Builder;
-};
-
-Function* IRGenContext::getPrototype(const std::string &Name) {
-  if (Function *ExistingProto = M->getFunction(Name))
-    return ExistingProto;
-  if (PrototypeAST *ProtoAST = Session.getPrototypeAST(Name))
-    return ProtoAST->IRGen(*this);
-  return nullptr;
-}
-
-/// CreateEntryBlockAlloca - Create an alloca instruction in the entry block of
-/// the function.  This is used for mutable variables etc.
-static AllocaInst *CreateEntryBlockAlloca(Function *TheFunction,
-                                          const std::string &VarName) {
-  IRBuilder<> TmpB(&TheFunction->getEntryBlock(),
-                   TheFunction->getEntryBlock().begin());
-  return TmpB.CreateAlloca(Type::getDoubleTy(TheFunction->getContext()),
-                           nullptr, VarName);
-}
-
-Value *NumberExprAST::IRGen(IRGenContext &C) const {
-  return ConstantFP::get(C.getLLVMContext(), APFloat(Val));
-}
-
-Value *VariableExprAST::IRGen(IRGenContext &C) const {
-  // Look this variable up in the function.
-  Value *V = C.NamedValues[Name];
-
-  if (!V)
-    return ErrorP<Value>("Unknown variable name '" + Name + "'");
-
-  // Load the value.
-  return C.getBuilder().CreateLoad(V, Name.c_str());
-}
-
-Value *UnaryExprAST::IRGen(IRGenContext &C) const {
-  if (Value *OperandV = Operand->IRGen(C)) {
-    std::string FnName = MakeLegalFunctionName(std::string("unary")+Opcode);
-    if (Function *F = C.getPrototype(FnName))
-      return C.getBuilder().CreateCall(F, OperandV, "unop");
-    return ErrorP<Value>("Unknown unary operator");
-  }
-
-  // Could not codegen operand - return null.
-  return nullptr;
-}
-
-Value *BinaryExprAST::IRGen(IRGenContext &C) const {
-  // Special case '=' because we don't want to emit the LHS as an expression.
-  if (Op == '=') {
-    // Assignment requires the LHS to be an identifier.
-    auto &LHSVar = static_cast<VariableExprAST &>(*LHS);
-    // Codegen the RHS.
-    Value *Val = RHS->IRGen(C);
-    if (!Val) return nullptr;
-
-    // Look up the name.
-    if (auto Variable = C.NamedValues[LHSVar.Name]) {
-      C.getBuilder().CreateStore(Val, Variable);
-      return Val;
-    }
-    return ErrorP<Value>("Unknown variable name");
-  }
-
-  Value *L = LHS->IRGen(C);
-  Value *R = RHS->IRGen(C);
-  if (!L || !R) return nullptr;
-
-  switch (Op) {
-  case '+': return C.getBuilder().CreateFAdd(L, R, "addtmp");
-  case '-': return C.getBuilder().CreateFSub(L, R, "subtmp");
-  case '*': return C.getBuilder().CreateFMul(L, R, "multmp");
-  case '/': return C.getBuilder().CreateFDiv(L, R, "divtmp");
-  case '<':
-    L = C.getBuilder().CreateFCmpULT(L, R, "cmptmp");
-    // Convert bool 0/1 to double 0.0 or 1.0
-    return C.getBuilder().CreateUIToFP(L, Type::getDoubleTy(C.getLLVMContext()),
-                                       "booltmp");
-  default: break;
-  }
-
-  // If it wasn't a builtin binary operator, it must be a user defined one. Emit
-  // a call to it.
-  std::string FnName = MakeLegalFunctionName(std::string("binary")+Op);
-  if (Function *F = C.getPrototype(FnName)) {
-    Value *Ops[] = { L, R };
-    return C.getBuilder().CreateCall(F, Ops, "binop");
-  }
-
-  return ErrorP<Value>("Unknown binary operator");
-}
-
-Value *CallExprAST::IRGen(IRGenContext &C) const {
-  // Look up the name in the global module table.
-  if (auto CalleeF = C.getPrototype(CalleeName)) {
-    // If argument mismatch error.
-    if (CalleeF->arg_size() != Args.size())
-      return ErrorP<Value>("Incorrect # arguments passed");
-
-    std::vector<Value*> ArgsV;
-    for (unsigned i = 0, e = Args.size(); i != e; ++i) {
-      ArgsV.push_back(Args[i]->IRGen(C));
-      if (!ArgsV.back()) return nullptr;
-    }
-
-    return C.getBuilder().CreateCall(CalleeF, ArgsV, "calltmp");
-  }
-
-  return ErrorP<Value>("Unknown function referenced");
-}
-
-Value *IfExprAST::IRGen(IRGenContext &C) const {
-  Value *CondV = Cond->IRGen(C);
-  if (!CondV) return nullptr;
-
-  // Convert condition to a bool by comparing equal to 0.0.
-  ConstantFP *FPZero =
-    ConstantFP::get(C.getLLVMContext(), APFloat(0.0));
-  CondV = C.getBuilder().CreateFCmpONE(CondV, FPZero, "ifcond");
-
-  Function *TheFunction = C.getBuilder().GetInsertBlock()->getParent();
-
-  // Create blocks for the then and else cases.  Insert the 'then' block at the
-  // end of the function.
-  BasicBlock *ThenBB = BasicBlock::Create(C.getLLVMContext(), "then", TheFunction);
-  BasicBlock *ElseBB = BasicBlock::Create(C.getLLVMContext(), "else");
-  BasicBlock *MergeBB = BasicBlock::Create(C.getLLVMContext(), "ifcont");
-
-  C.getBuilder().CreateCondBr(CondV, ThenBB, ElseBB);
-
-  // Emit then value.
-  C.getBuilder().SetInsertPoint(ThenBB);
-
-  Value *ThenV = Then->IRGen(C);
-  if (!ThenV) return nullptr;
-
-  C.getBuilder().CreateBr(MergeBB);
-  // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
-  ThenBB = C.getBuilder().GetInsertBlock();
-
-  // Emit else block.
-  TheFunction->getBasicBlockList().push_back(ElseBB);
-  C.getBuilder().SetInsertPoint(ElseBB);
-
-  Value *ElseV = Else->IRGen(C);
-  if (!ElseV) return nullptr;
-
-  C.getBuilder().CreateBr(MergeBB);
-  // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
-  ElseBB = C.getBuilder().GetInsertBlock();
-
-  // Emit merge block.
-  TheFunction->getBasicBlockList().push_back(MergeBB);
-  C.getBuilder().SetInsertPoint(MergeBB);
-  PHINode *PN = C.getBuilder().CreatePHI(Type::getDoubleTy(C.getLLVMContext()),
-                                         2, "iftmp");
-
-  PN->addIncoming(ThenV, ThenBB);
-  PN->addIncoming(ElseV, ElseBB);
-  return PN;
-}
-
-Value *ForExprAST::IRGen(IRGenContext &C) const {
-  // Output this as:
-  //   var = alloca double
-  //   ...
-  //   start = startexpr
-  //   store start -> var
-  //   goto loop
-  // loop:
-  //   ...
-  //   bodyexpr
-  //   ...
-  // loopend:
-  //   step = stepexpr
-  //   endcond = endexpr
-  //
-  //   curvar = load var
-  //   nextvar = curvar + step
-  //   store nextvar -> var
-  //   br endcond, loop, endloop
-  // outloop:
-
-  Function *TheFunction = C.getBuilder().GetInsertBlock()->getParent();
-
-  // Create an alloca for the variable in the entry block.
-  AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
-
-  // Emit the start code first, without 'variable' in scope.
-  Value *StartVal = Start->IRGen(C);
-  if (!StartVal) return nullptr;
-
-  // Store the value into the alloca.
-  C.getBuilder().CreateStore(StartVal, Alloca);
-
-  // Make the new basic block for the loop header, inserting after current
-  // block.
-  BasicBlock *LoopBB =
-      BasicBlock::Create(C.getLLVMContext(), "loop", TheFunction);
-
-  // Insert an explicit fall through from the current block to the LoopBB.
-  C.getBuilder().CreateBr(LoopBB);
-
-  // Start insertion in LoopBB.
-  C.getBuilder().SetInsertPoint(LoopBB);
-
-  // Within the loop, the variable is defined equal to the PHI node.  If it
-  // shadows an existing variable, we have to restore it, so save it now.
-  AllocaInst *OldVal = C.NamedValues[VarName];
-  C.NamedValues[VarName] = Alloca;
-
-  // Emit the body of the loop.  This, like any other expr, can change the
-  // current BB.  Note that we ignore the value computed by the body, but don't
-  // allow an error.
-  if (!Body->IRGen(C))
-    return nullptr;
-
-  // Emit the step value.
-  Value *StepVal;
-  if (Step) {
-    StepVal = Step->IRGen(C);
-    if (!StepVal) return nullptr;
-  } else {
-    // If not specified, use 1.0.
-    StepVal = ConstantFP::get(C.getLLVMContext(), APFloat(1.0));
-  }
-
-  // Compute the end condition.
-  Value *EndCond = End->IRGen(C);
-  if (!EndCond) return nullptr;
-
-  // Reload, increment, and restore the alloca.  This handles the case where
-  // the body of the loop mutates the variable.
-  Value *CurVar = C.getBuilder().CreateLoad(Alloca, VarName.c_str());
-  Value *NextVar = C.getBuilder().CreateFAdd(CurVar, StepVal, "nextvar");
-  C.getBuilder().CreateStore(NextVar, Alloca);
-
-  // Convert condition to a bool by comparing equal to 0.0.
-  EndCond = C.getBuilder().CreateFCmpONE(
-      EndCond, ConstantFP::get(C.getLLVMContext(), APFloat(0.0)), "loopcond");
-
-  // Create the "after loop" block and insert it.
-  BasicBlock *AfterBB =
-      BasicBlock::Create(C.getLLVMContext(), "afterloop", TheFunction);
-
-  // Insert the conditional branch into the end of LoopEndBB.
-  C.getBuilder().CreateCondBr(EndCond, LoopBB, AfterBB);
-
-  // Any new code will be inserted in AfterBB.
-  C.getBuilder().SetInsertPoint(AfterBB);
-
-  // Restore the unshadowed variable.
-  if (OldVal)
-    C.NamedValues[VarName] = OldVal;
-  else
-    C.NamedValues.erase(VarName);
-
-  // for expr always returns 0.0.
-  return Constant::getNullValue(Type::getDoubleTy(C.getLLVMContext()));
-}
-
-Value *VarExprAST::IRGen(IRGenContext &C) const {
-  std::vector<AllocaInst *> OldBindings;
-
-  Function *TheFunction = C.getBuilder().GetInsertBlock()->getParent();
-
-  // Register all variables and emit their initializer.
-  for (unsigned i = 0, e = VarBindings.size(); i != e; ++i) {
-    auto &VarName = VarBindings[i].first;
-    auto &Init = VarBindings[i].second;
-
-    // Emit the initializer before adding the variable to scope, this prevents
-    // the initializer from referencing the variable itself, and permits stuff
-    // like this:
-    //  var a = 1 in
-    //    var a = a in ...   # refers to outer 'a'.
-    Value *InitVal;
-    if (Init) {
-      InitVal = Init->IRGen(C);
-      if (!InitVal) return nullptr;
-    } else // If not specified, use 0.0.
-      InitVal = ConstantFP::get(C.getLLVMContext(), APFloat(0.0));
-
-    AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
-    C.getBuilder().CreateStore(InitVal, Alloca);
-
-    // Remember the old variable binding so that we can restore the binding when
-    // we unrecurse.
-    OldBindings.push_back(C.NamedValues[VarName]);
-
-    // Remember this binding.
-    C.NamedValues[VarName] = Alloca;
-  }
-
-  // Codegen the body, now that all vars are in scope.
-  Value *BodyVal = Body->IRGen(C);
-  if (!BodyVal) return nullptr;
-
-  // Pop all our variables from scope.
-  for (unsigned i = 0, e = VarBindings.size(); i != e; ++i)
-    C.NamedValues[VarBindings[i].first] = OldBindings[i];
-
-  // Return the body computation.
-  return BodyVal;
-}
-
-Function *PrototypeAST::IRGen(IRGenContext &C) const {
-  std::string FnName = MakeLegalFunctionName(Name);
-
-  // Make the function type:  double(double,double) etc.
-  std::vector<Type *> Doubles(Args.size(),
-                              Type::getDoubleTy(C.getLLVMContext()));
-  FunctionType *FT =
-      FunctionType::get(Type::getDoubleTy(C.getLLVMContext()), Doubles, false);
-  Function *F = Function::Create(FT, Function::ExternalLinkage, FnName,
-                                 &C.getM());
-
-  // If F conflicted, there was already something named 'FnName'.  If it has a
-  // body, don't allow redefinition or reextern.
-  if (F->getName() != FnName) {
-    // Delete the one we just made and get the existing one.
-    F->eraseFromParent();
-    F = C.getM().getFunction(Name);
-
-    // If F already has a body, reject this.
-    if (!F->empty()) {
-      ErrorP<Function>("redefinition of function");
-      return nullptr;
-    }
-
-    // If F took a different number of args, reject.
-    if (F->arg_size() != Args.size()) {
-      ErrorP<Function>("redefinition of function with different # args");
-      return nullptr;
-    }
-  }
-
-  // Set names for all arguments.
-  unsigned Idx = 0;
-  for (Function::arg_iterator AI = F->arg_begin(); Idx != Args.size();
-       ++AI, ++Idx)
-    AI->setName(Args[Idx]);
-
-  return F;
-}
-
-/// CreateArgumentAllocas - Create an alloca for each argument and register the
-/// argument in the symbol table so that references to it will succeed.
-void PrototypeAST::CreateArgumentAllocas(Function *F, IRGenContext &C) {
-  Function::arg_iterator AI = F->arg_begin();
-  for (unsigned Idx = 0, e = Args.size(); Idx != e; ++Idx, ++AI) {
-    // Create an alloca for this variable.
-    AllocaInst *Alloca = CreateEntryBlockAlloca(F, Args[Idx]);
-
-    // Store the initial value into the alloca.
-    C.getBuilder().CreateStore(&*AI, Alloca);
-
-    // Add arguments to variable symbol table.
-    C.NamedValues[Args[Idx]] = Alloca;
-  }
-}
-
-Function *FunctionAST::IRGen(IRGenContext &C) const {
-  C.NamedValues.clear();
-
-  Function *TheFunction = Proto->IRGen(C);
-  if (!TheFunction)
-    return nullptr;
-
-  // If this is an operator, install it.
-  if (Proto->isBinaryOp())
-    BinopPrecedence[Proto->getOperatorName()] = Proto->Precedence;
-
-  // Create a new basic block to start insertion into.
-  BasicBlock *BB = BasicBlock::Create(C.getLLVMContext(), "entry", TheFunction);
-  C.getBuilder().SetInsertPoint(BB);
-
-  // Add all arguments to the symbol table and create their allocas.
-  Proto->CreateArgumentAllocas(TheFunction, C);
-
-  if (Value *RetVal = Body->IRGen(C)) {
-    // Finish off the function.
-    C.getBuilder().CreateRet(RetVal);
-
-    // Validate the generated code, checking for consistency.
-    verifyFunction(*TheFunction);
-
-    return TheFunction;
-  }
-
-  // Error reading body, remove function.
-  TheFunction->eraseFromParent();
-
-  if (Proto->isBinaryOp())
-    BinopPrecedence.erase(Proto->getOperatorName());
-  return nullptr;
-}
-
-//===----------------------------------------------------------------------===//
-// Top-Level parsing and JIT Driver
-//===----------------------------------------------------------------------===//
-
-static std::unique_ptr<llvm::Module> IRGen(SessionContext &S,
-                                           const FunctionAST &F) {
-  IRGenContext C(S);
-  auto LF = F.IRGen(C);
-  if (!LF)
-    return nullptr;
-#ifndef MINIMAL_STDERR_OUTPUT
-  fprintf(stderr, "Read function definition:");
-  LF->dump();
-#endif
-  return C.takeM();
-}
-
-template <typename T>
-static std::vector<T> singletonSet(T t) {
-  std::vector<T> Vec;
-  Vec.push_back(std::move(t));
-  return Vec;
-}
-
-class KaleidoscopeJIT {
-public:
-  typedef ObjectLinkingLayer<> ObjLayerT;
-  typedef IRCompileLayer<ObjLayerT> CompileLayerT;
-  typedef LazyEmittingLayer<CompileLayerT> LazyEmitLayerT;
-  typedef LazyEmitLayerT::ModuleSetHandleT ModuleHandleT;
-
-  KaleidoscopeJIT(SessionContext &Session)
-    : Session(Session),
-      CompileLayer(ObjectLayer, SimpleCompiler(Session.getTarget())),
-      LazyEmitLayer(CompileLayer) {}
-
-  std::string mangle(const std::string &Name) {
-    std::string MangledName;
-    {
-      raw_string_ostream MangledNameStream(MangledName);
-      Mangler::getNameWithPrefix(MangledNameStream, Name,
-                                 Session.getTarget().createDataLayout());
-    }
-    return MangledName;
-  }
-
-  void addFunctionAST(std::unique_ptr<FunctionAST> FnAST) {
-    std::cerr << "Adding AST: " << FnAST->Proto->Name << "\n";
-    FunctionDefs[mangle(FnAST->Proto->Name)] = std::move(FnAST);
-  }
-
-  ModuleHandleT addModule(std::unique_ptr<Module> M) {
-    // We need a memory manager to allocate memory and resolve symbols for this
-    // new module. Create one that resolves symbols by looking back into the
-    // JIT.
-    auto Resolver = createLambdaResolver(
-                      [&](const std::string &Name) {
-                        // First try to find 'Name' within the JIT.
-                        if (auto Symbol = findSymbol(Name))
-                          return RuntimeDyld::SymbolInfo(Symbol.getAddress(),
-                                                         Symbol.getFlags());
-
-                        // If we don't already have a definition of 'Name' then search
-                        // the ASTs.
-                        return searchFunctionASTs(Name);
-                      },
-                      [](const std::string &S) { return nullptr; } );
-
-    return LazyEmitLayer.addModuleSet(singletonSet(std::move(M)),
-                                      make_unique<SectionMemoryManager>(),
-                                      std::move(Resolver));
-  }
-
-  void removeModule(ModuleHandleT H) { LazyEmitLayer.removeModuleSet(H); }
-
-  JITSymbol findSymbol(const std::string &Name) {
-    return LazyEmitLayer.findSymbol(Name, true);
-  }
-
-  JITSymbol findSymbolIn(ModuleHandleT H, const std::string &Name) {
-    return LazyEmitLayer.findSymbolIn(H, Name, true);
-  }
-
-  JITSymbol findUnmangledSymbol(const std::string &Name) {
-    return findSymbol(mangle(Name));
-  }
-
-private:
-  // This method searches the FunctionDefs map for a definition of 'Name'. If it
-  // finds one it generates a stub for it and returns the address of the stub.
-  RuntimeDyld::SymbolInfo searchFunctionASTs(const std::string &Name) {
-    auto DefI = FunctionDefs.find(Name);
-    if (DefI == FunctionDefs.end())
-      return nullptr;
-
-    // Take the FunctionAST out of the map.
-    auto FnAST = std::move(DefI->second);
-    FunctionDefs.erase(DefI);
-
-    // IRGen the AST, add it to the JIT, and return the address for it.
-    auto H = addModule(IRGen(Session, *FnAST));
-    auto Sym = findSymbolIn(H, Name);
-    return RuntimeDyld::SymbolInfo(Sym.getAddress(), Sym.getFlags());
-  }
-
-  SessionContext &Session;
-  ObjLayerT ObjectLayer;
-  CompileLayerT CompileLayer;
-  LazyEmitLayerT LazyEmitLayer;
-
-  std::map<std::string, std::unique_ptr<FunctionAST>> FunctionDefs;
-};
-
-static void HandleDefinition(SessionContext &S, KaleidoscopeJIT &J) {
-  if (auto F = ParseDefinition()) {
-    S.addPrototypeAST(llvm::make_unique<PrototypeAST>(*F->Proto));
-    J.addFunctionAST(std::move(F));
-  } else {
-    // Skip token for error recovery.
-    getNextToken();
-  }
-}
-
-static void HandleExtern(SessionContext &S) {
-  if (auto P = ParseExtern())
-    S.addPrototypeAST(std::move(P));
-  else {
-    // Skip token for error recovery.
-    getNextToken();
-  }
-}
-
-static void HandleTopLevelExpression(SessionContext &S, KaleidoscopeJIT &J) {
-  // Evaluate a top-level expression into an anonymous function.
-  if (auto F = ParseTopLevelExpr()) {
-    IRGenContext C(S);
-    if (auto ExprFunc = F->IRGen(C)) {
-#ifndef MINIMAL_STDERR_OUTPUT
-      std::cerr << "Expression function:\n";
-      ExprFunc->dump();
-#endif
-      // Add the CodeGen'd module to the JIT. Keep a handle to it: We can remove
-      // this module as soon as we've executed Function ExprFunc.
-      auto H = J.addModule(C.takeM());
-
-      // Get the address of the JIT'd function in memory.
-      auto ExprSymbol = J.findUnmangledSymbol("__anon_expr");
-
-      // Cast it to the right type (takes no arguments, returns a double) so we
-      // can call it as a native function.
-      double (*FP)() = (double (*)())(intptr_t)ExprSymbol.getAddress();
-#ifdef MINIMAL_STDERR_OUTPUT
-      FP();
-#else
-      std::cerr << "Evaluated to " << FP() << "\n";
-#endif
-
-      // Remove the function.
-      J.removeModule(H);
-    }
-  } else {
-    // Skip token for error recovery.
-    getNextToken();
-  }
-}
-
-/// top ::= definition | external | expression | ';'
-static void MainLoop() {
-  LLVMContext TheContext;
-  SessionContext S(TheContext);
-  KaleidoscopeJIT J(S);
-
-  while (true) {
-    switch (CurTok) {
-    case tok_eof:    return;
-    case ';':        getNextToken(); continue;  // ignore top-level semicolons.
-    case tok_def:    HandleDefinition(S, J); break;
-    case tok_extern: HandleExtern(S); break;
-    default:         HandleTopLevelExpression(S, J); break;
-    }
-#ifndef MINIMAL_STDERR_OUTPUT
-    std::cerr << "ready> ";
-#endif
-  }
-}
-
-//===----------------------------------------------------------------------===//
-// "Library" functions that can be "extern'd" from user code.
-//===----------------------------------------------------------------------===//
-
-/// putchard - putchar that takes a double and returns 0.
-extern "C"
-double putchard(double X) {
-  putchar((char)X);
-  return 0;
-}
-
-/// printd - printf that takes a double prints it as "%f\n", returning 0.
-extern "C"
-double printd(double X) {
-  printf("%f", X);
-  return 0;
-}
-
-extern "C"
-double printlf() {
-  printf("\n");
-  return 0;
-}
-
-//===----------------------------------------------------------------------===//
-// Main driver code.
-//===----------------------------------------------------------------------===//
-
-int main() {
-  InitializeNativeTarget();
-  InitializeNativeTargetAsmPrinter();
-  InitializeNativeTargetAsmParser();
-
-  // Install standard binary operators.
-  // 1 is lowest precedence.
-  BinopPrecedence['='] = 2;
-  BinopPrecedence['<'] = 10;
-  BinopPrecedence['+'] = 20;
-  BinopPrecedence['-'] = 20;
-  BinopPrecedence['/'] = 40;
-  BinopPrecedence['*'] = 40;  // highest.
-
-  // Prime the first token.
-#ifndef MINIMAL_STDERR_OUTPUT
-  std::cerr << "ready> ";
-#endif
-  getNextToken();
-
-  std::cerr << std::fixed;
-
-  // Run the main "interpreter loop" now.
-  MainLoop();
-
-  return 0;
-}