From 8e3521f6e06ee217cb8d395d0ab4de6e6f610dbb Mon Sep 17 00:00:00 2001
From: "Prof. Ronald Moore" <ronald.moore@h-da.de>
Date: Wed, 29 Apr 2020 15:56:49 +0200
Subject: [PATCH] Imported LLVM example

---
 LLVM/cplusplus/KaleidoscopeJIT.h   |  139 +++
 LLVM/cplusplus/LICENSE.TXT         |  279 ++++++
 LLVM/cplusplus/Makefile            |  103 ++
 LLVM/cplusplus/ModuleMaker.cpp     |   70 ++
 LLVM/cplusplus/README.md           |  132 +++
 LLVM/cplusplus/fibonacci.cpp       |  148 +++
 LLVM/cplusplus/tests/fibonacci.kal |    9 +
 LLVM/cplusplus/tests/test2.kal     |    4 +
 LLVM/cplusplus/tests/test3.kal     |    7 +
 LLVM/cplusplus/tests/test4.kal     |   12 +
 LLVM/cplusplus/tests/test5.kal     |   26 +
 LLVM/cplusplus/tests/test6.kal     |  101 ++
 LLVM/cplusplus/tests/test7.kal     |   22 +
 LLVM/cplusplus/tests/test8.cpp     |    9 +
 LLVM/cplusplus/tests/test8.kal     |    1 +
 LLVM/cplusplus/tests/test9.kal     |    7 +
 LLVM/cplusplus/toy2.cpp            |  447 +++++++++
 LLVM/cplusplus/toy3.cpp            |  610 ++++++++++++
 LLVM/cplusplus/toy4.cpp            |  701 ++++++++++++++
 LLVM/cplusplus/toy5.cpp            |  975 +++++++++++++++++++
 LLVM/cplusplus/toy6.cpp            | 1094 +++++++++++++++++++++
 LLVM/cplusplus/toy7.cpp            | 1265 ++++++++++++++++++++++++
 LLVM/cplusplus/toy8.cpp            | 1270 ++++++++++++++++++++++++
 LLVM/cplusplus/toy9.cpp            | 1452 ++++++++++++++++++++++++++++
 24 files changed, 8883 insertions(+)
 create mode 100644 LLVM/cplusplus/KaleidoscopeJIT.h
 create mode 100644 LLVM/cplusplus/LICENSE.TXT
 create mode 100644 LLVM/cplusplus/Makefile
 create mode 100644 LLVM/cplusplus/ModuleMaker.cpp
 create mode 100644 LLVM/cplusplus/README.md
 create mode 100644 LLVM/cplusplus/fibonacci.cpp
 create mode 100644 LLVM/cplusplus/tests/fibonacci.kal
 create mode 100644 LLVM/cplusplus/tests/test2.kal
 create mode 100644 LLVM/cplusplus/tests/test3.kal
 create mode 100644 LLVM/cplusplus/tests/test4.kal
 create mode 100644 LLVM/cplusplus/tests/test5.kal
 create mode 100644 LLVM/cplusplus/tests/test6.kal
 create mode 100644 LLVM/cplusplus/tests/test7.kal
 create mode 100644 LLVM/cplusplus/tests/test8.cpp
 create mode 100644 LLVM/cplusplus/tests/test8.kal
 create mode 100644 LLVM/cplusplus/tests/test9.kal
 create mode 100644 LLVM/cplusplus/toy2.cpp
 create mode 100644 LLVM/cplusplus/toy3.cpp
 create mode 100644 LLVM/cplusplus/toy4.cpp
 create mode 100644 LLVM/cplusplus/toy5.cpp
 create mode 100644 LLVM/cplusplus/toy6.cpp
 create mode 100644 LLVM/cplusplus/toy7.cpp
 create mode 100644 LLVM/cplusplus/toy8.cpp
 create mode 100644 LLVM/cplusplus/toy9.cpp

diff --git a/LLVM/cplusplus/KaleidoscopeJIT.h b/LLVM/cplusplus/KaleidoscopeJIT.h
new file mode 100644
index 0000000..a253a97
--- /dev/null
+++ b/LLVM/cplusplus/KaleidoscopeJIT.h
@@ -0,0 +1,139 @@
+//===- KaleidoscopeJIT.h - A simple JIT for Kaleidoscope --------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Contains a simple JIT definition for use in the kaleidoscope tutorials.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_EXECUTIONENGINE_ORC_KALEIDOSCOPEJIT_H
+#define LLVM_EXECUTIONENGINE_ORC_KALEIDOSCOPEJIT_H
+
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/iterator_range.h"
+#include "llvm/ExecutionEngine/ExecutionEngine.h"
+#include "llvm/ExecutionEngine/JITSymbol.h"
+#include "llvm/ExecutionEngine/Orc/CompileUtils.h"
+#include "llvm/ExecutionEngine/Orc/IRCompileLayer.h"
+#include "llvm/ExecutionEngine/Orc/LambdaResolver.h"
+#include "llvm/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.h"
+#include "llvm/ExecutionEngine/RTDyldMemoryManager.h"
+#include "llvm/ExecutionEngine/SectionMemoryManager.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Mangler.h"
+#include "llvm/Support/DynamicLibrary.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetMachine.h"
+#include <algorithm>
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+namespace llvm {
+namespace orc {
+
+class KaleidoscopeJIT {
+public:
+  using ObjLayerT = LegacyRTDyldObjectLinkingLayer;
+  using CompileLayerT = LegacyIRCompileLayer<ObjLayerT, SimpleCompiler>;
+
+  KaleidoscopeJIT()
+      : Resolver(createLegacyLookupResolver(
+            ES,
+            [this](const std::string &Name) { return findMangledSymbol(Name); },
+            [](Error Err) { cantFail(std::move(Err), "lookupFlags failed"); })),
+        TM(EngineBuilder().selectTarget()), DL(TM->createDataLayout()),
+        ObjectLayer(AcknowledgeORCv1Deprecation, ES,
+                    [this](VModuleKey) {
+                      return ObjLayerT::Resources{
+                          std::make_shared<SectionMemoryManager>(), Resolver};
+                    }),
+        CompileLayer(AcknowledgeORCv1Deprecation, ObjectLayer,
+                     SimpleCompiler(*TM)) {
+    llvm::sys::DynamicLibrary::LoadLibraryPermanently(nullptr);
+  }
+
+  TargetMachine &getTargetMachine() { return *TM; }
+
+  VModuleKey addModule(std::unique_ptr<Module> M) {
+    auto K = ES.allocateVModule();
+    cantFail(CompileLayer.addModule(K, std::move(M)));
+    ModuleKeys.push_back(K);
+    return K;
+  }
+
+  void removeModule(VModuleKey K) {
+    ModuleKeys.erase(find(ModuleKeys, K));
+    cantFail(CompileLayer.removeModule(K));
+  }
+
+  JITSymbol findSymbol(const std::string Name) {
+    return findMangledSymbol(mangle(Name));
+  }
+
+private:
+  std::string mangle(const std::string &Name) {
+    std::string MangledName;
+    {
+      raw_string_ostream MangledNameStream(MangledName);
+      Mangler::getNameWithPrefix(MangledNameStream, Name, DL);
+    }
+    return MangledName;
+  }
+
+  JITSymbol findMangledSymbol(const std::string &Name) {
+#ifdef _WIN32
+    // The symbol lookup of ObjectLinkingLayer uses the SymbolRef::SF_Exported
+    // flag to decide whether a symbol will be visible or not, when we call
+    // IRCompileLayer::findSymbolIn with ExportedSymbolsOnly set to true.
+    //
+    // But for Windows COFF objects, this flag is currently never set.
+    // For a potential solution see: https://reviews.llvm.org/rL258665
+    // For now, we allow non-exported symbols on Windows as a workaround.
+    const bool ExportedSymbolsOnly = false;
+#else
+    const bool ExportedSymbolsOnly = true;
+#endif
+
+    // Search modules in reverse order: from last added to first added.
+    // This is the opposite of the usual search order for dlsym, but makes more
+    // sense in a REPL where we want to bind to the newest available definition.
+    for (auto H : make_range(ModuleKeys.rbegin(), ModuleKeys.rend()))
+      if (auto Sym = CompileLayer.findSymbolIn(H, Name, ExportedSymbolsOnly))
+        return Sym;
+
+    // If we can't find the symbol in the JIT, try looking in the host process.
+    if (auto SymAddr = RTDyldMemoryManager::getSymbolAddressInProcess(Name))
+      return JITSymbol(SymAddr, JITSymbolFlags::Exported);
+
+#ifdef _WIN32
+    // For Windows retry without "_" at beginning, as RTDyldMemoryManager uses
+    // GetProcAddress and standard libraries like msvcrt.dll use names
+    // with and without "_" (for example "_itoa" but "sin").
+    if (Name.length() > 2 && Name[0] == '_')
+      if (auto SymAddr =
+              RTDyldMemoryManager::getSymbolAddressInProcess(Name.substr(1)))
+        return JITSymbol(SymAddr, JITSymbolFlags::Exported);
+#endif
+
+    return nullptr;
+  }
+
+  ExecutionSession ES;
+  std::shared_ptr<SymbolResolver> Resolver;
+  std::unique_ptr<TargetMachine> TM;
+  const DataLayout DL;
+  ObjLayerT ObjectLayer;
+  CompileLayerT CompileLayer;
+  std::vector<VModuleKey> ModuleKeys;
+};
+
+} // end namespace orc
+} // end namespace llvm
+
+#endif // LLVM_EXECUTIONENGINE_ORC_KALEIDOSCOPEJIT_H
diff --git a/LLVM/cplusplus/LICENSE.TXT b/LLVM/cplusplus/LICENSE.TXT
new file mode 100644
index 0000000..fa6ac54
--- /dev/null
+++ b/LLVM/cplusplus/LICENSE.TXT
@@ -0,0 +1,279 @@
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diff --git a/LLVM/cplusplus/Makefile b/LLVM/cplusplus/Makefile
new file mode 100644
index 0000000..5234e25
--- /dev/null
+++ b/LLVM/cplusplus/Makefile
@@ -0,0 +1,103 @@
+# Very rudimentary Makefile for the llvm tutorial
+# See http://llvm.org/docs/tutorial/
+# See also http://koichitamura.blogspot.de/2011/01/since-i-went-to-held-several-weeks-ago.html
+# for a necessary "fix" (!)
+#
+# This Makefile written by Prof. R. C. Moore, fbi.h-da.de
+
+PROGS := ModuleMaker fibonacci toy2 toy3 toy4 toy5 toy6 toy7 toy8 toy9
+
+# Uncomment only one of the next two lines (choose your c++ compiler)
+# CC=g++
+CC := clang++
+
+# Now, how to compile in LLVM?
+# LLVM VERSION 3.9.1 (2017) and possibly LLVM Version 4
+# The Tutorial (Chapter 3) does it like this:
+# clang++ -g -O3 toy.cpp `llvm-config --cxxflags --ldflags --system-libs --libs core` -o toy
+# based on that, and some experimentation, we got, for LLVM 3.6...
+# CFLAGS=-std=c++11 `llvm-config --cxxflags --ldflags --system-libs --libs all` -rdynamic -O3
+# Now, for llvm >= 3.7.1, further experience has brought us to....
+# At one time, we piped the output of llvm-config to sed s/no-maybe/no/ .
+# Hopefully this is no longer necessary... ?
+# (sed was used to hide an incompatibility between llvm-config and clang)
+
+LLVM_FLAGS := `llvm-config --cxxflags --ldflags --system-libs --libs all `
+
+CFLAGS :=  $(LLVM_FLAGS) -rdynamic -O3
+
+
+## More preliminaries
+# See https://www.gnu.org/software/make/manual/html_node/Special-Targets.html
+# In this makefile, we want to keep going even if we find errors
+.IGNORE :
+
+# Further, we do not want multiple things built at once, even if make called with -j2
+.NOTPARALLEL :
+
+# Tell make that the following "targets" are "phony"
+# Cf. https://www.gnu.org/software/make/manual/html_node/Phony-Targets.html#Phony-Targets
+.PHONY : all tests clean testclean
+
+##  Now, the targets -- the things that will get made!
+
+all: $(PROGS)
+
+$(PROGS): %: %.cpp
+	$(CC) -g $< $(CFLAGS) -o $@
+
+clean: testclean
+	$(RM) -fv *~ $(PROGS) ModuleMaker.bc fib test8 test8.o test9
+
+testclean:
+	rm -fv *~ *.output test8.o test9
+
+testModuleMaker: ModuleMaker
+	echo && echo "Testing ModuleMaker (expect 5)...\n"
+	@./ModuleMaker >ModuleMaker.bc
+	@lli ModuleMaker.bc || echo $$?
+
+# WARNING: testFibonacci broken (with LLVM and clang 3.7.1)
+testFibonacci: fibonacci
+	echo && echo "\n===================> Testing fibonacci (expect 46368)...\n"
+	-./fibonacci
+
+test2: toy2 tests/test2.kal
+	echo && echo "\n===================> Testing toy2.. (expecting 1 error)\n"
+	-./toy2 <tests/test2.kal
+
+test3: toy3 tests/test3.kal
+	echo && echo "\n===================> Testing toy3...\n"
+	-./toy3 <tests/test3.kal
+
+test4: toy4 tests/test4.kal
+	echo && echo "\n===================> Testing toy4...\n"
+	-./toy4 <tests/test4.kal
+
+test5: toy5 tests/test5.kal
+	echo && echo "\n===================> Testing toy5...\n"
+	-./toy5 <tests/test5.kal
+
+test6: toy6 tests/test6.kal
+	echo && echo "\n===================> Testing toy6...\n"
+	-./toy6 <tests/test6.kal
+
+test7: toy7 tests/test7.kal
+	echo && echo "\n===================> Testing toy7...\n"
+	-./toy7 <tests/test7.kal
+
+test8: toy8 tests/test8.kal toy8.cpp
+	echo && echo "\n===================> Testing toy8... (expect 42, of course)\n"
+	-./toy8 <tests/test8.kal
+	-clang++ tests/test8.cpp test8.o -o test8
+	-./test8
+
+test9: toy9 tests/test9.kal
+	echo && echo "\n===================> Testing toy9...\n"
+	-./toy9 <tests/test9.kal |& clang -x ir - -o test9
+	-./test9
+
+# WARNING: test9 removed since broken (with LLVM and clang <= 3.9)
+# NOTE: fibonacci added BACK to tests since it's working again!
+tests: testModuleMaker testFibonacci test2 test3 test4 test5 test6 test7 test8 
+
diff --git a/LLVM/cplusplus/ModuleMaker.cpp b/LLVM/cplusplus/ModuleMaker.cpp
new file mode 100644
index 0000000..beff40a
--- /dev/null
+++ b/LLVM/cplusplus/ModuleMaker.cpp
@@ -0,0 +1,70 @@
+//===- examples/ModuleMaker/ModuleMaker.cpp - Example project ---*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This programs is a simple example that creates an LLVM module "from scratch",
+// emitting it as a bitcode file to standard out.  This is just to show how
+// LLVM projects work and to demonstrate some of the LLVM APIs.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Bitcode/BitcodeWriter.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/InstrTypes.h"
+#include "llvm/IR/Instruction.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Type.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+
+int main() {
+  LLVMContext Context;
+
+  // Create the "module" or "program" or "translation unit" to hold the
+  // function
+  Module *M = new Module("test", Context);
+
+  // Create the main function: first create the type 'int ()'
+  FunctionType *FT =
+    FunctionType::get(Type::getInt32Ty(Context), /*not vararg*/false);
+
+  // By passing a module as the last parameter to the Function constructor,
+  // it automatically gets appended to the Module.
+  Function *F = Function::Create(FT, Function::ExternalLinkage, "main", M);
+
+  // Add a basic block to the function... again, it automatically inserts
+  // because of the last argument.
+  BasicBlock *BB = BasicBlock::Create(Context, "EntryBlock", F);
+
+  // Get pointers to the constant integers...
+  Value *Two = ConstantInt::get(Type::getInt32Ty(Context), 2);
+  Value *Three = ConstantInt::get(Type::getInt32Ty(Context), 3);
+
+  // Create the add instruction... does not insert...
+  Instruction *Add = BinaryOperator::Create(Instruction::Add, Two, Three,
+                                            "addresult");
+
+  // explicitly insert it into the basic block...
+  BB->getInstList().push_back(Add);
+
+  // Create the return instruction and add it to the basic block
+  BB->getInstList().push_back(ReturnInst::Create(Context, Add));
+
+  // Output the bitcode file to stdout
+  WriteBitcodeToFile(*M, outs());
+
+  // Delete the module and all of its contents.
+  delete M;
+  return 0;
+}
diff --git a/LLVM/cplusplus/README.md b/LLVM/cplusplus/README.md
new file mode 100644
index 0000000..7419b40
--- /dev/null
+++ b/LLVM/cplusplus/README.md
@@ -0,0 +1,132 @@
+Introduction
+============
+
+This Directory contains various examples for working with the LLVM tools.
+
+All interesting files are from the LLVM project -
+See http://llvm.org and in particular http://www.llvm.org/docs/
+for more information.
+
+This collection was prepared by Prof. R. C. Moore, fbi.h-da.de
+in May 2017 for the Compiler Construction course. No warranty implied or expressed.
+See LICENSE.TXT for the original license.
+
+This version has been prepared for LLVM 4.0 (using Arch Linux in a vagrant box)
+in May 2017.
+
+This version can be fairly easily adpated to work with LLVM 3.9. 
+It does NOT work with earlier versions of LLVM.
+
+All of the example files (fibonacci.cpp, ModuleMaker.cpp and toy*.cpp):
+
+ - are available in the LLVM source tree, for example by running the
+   following:
+       svn co https://llvm.org/svn/llvm-project/llvm/tags/RELEASE_400/final/
+   or by downloading the whole source tarball, where you will find a directory
+   named "examples", from:
+        http://llvm.org/releases/
+   or directly from
+        http://releases.llvm.org/10.0.0/llvm-10.0.0.src.tar.xz
+
+ - the directory structure has been simplified, some files have been renamed,
+   and a new Makefile is provided which is much simpler than the original cmake
+   system (but not guarenteed to work outside Linux).  Test files have also
+   been added. See below. 
+
+Still, it should be emphasized that there is nothing really new here -- apart 
+from the packaging, everything here is from the LLVM project!
+
+Manifest ("Table of Contents")
+===============================
+
+You should have received the following files:
+
+ * `fibonacci.cpp`  
+This is a compiler without a front-end, so to speak,
+but with an interpreter built in - see ModuleMaker for
+an even simpler example.
+ * `LICENSE.TXT`         
+The LLVM Release Open Source License
+(taken verbatim from the University of Illinois/NCSA,
+https://github.com/llvm/llvm-project/blob/master/llvm/LICENSE.TXT).
+ * `Makefile`  
+A Makefile, not supplied by LLVM but written instead
+by R. Moore - to make this collection work without the
+rest of the LLVM source tree.  You will (of course)
+need the LLVM tool set installed (clang, clang++ &
+llvm-config and the llvm libs, at the very least).
+ * `ModuleMaker.cpp`   
+Another example provided in the LLVM source tree.
+This file produces binary LLVM bit code for a program
+which does nothing but return a status of 5. LLVM
+bit code can be run using the LLVM "lli" tool.
+Thus, you should be able to do the following:
+
+```
+make ModuleMaker  
+./ModuleMaker >status5.bc  
+lli status5.bc  
+echo $? # should print "5"  
+```
+
+"Hello World" doesn't get much simpler than this!
+(Running "make testModuleMaker" does this, by the way).
+ * `README.md`            
+This file.
+ * `KaleidoscopeJIT.h`   
+A header file used by some of the toy4.cpp - toy9.cpp.
+This version works with LLVM 10. 
+ * `tests`            
+A directory containing files in the Kaleidoscope
+language, taken from the LLVM Tutorial, see
+https://llvm.org/docs/tutorial/MyFirstLanguageFrontend/index.html
+Some, but not all, of these are used by "make tests".
+ * `toy2.cpp` - `toy9.cpp`          
+The source code from the Tutorial, Chapters 2 through 9.
+
+All of the above Chapters are available at
+https://llvm.org/docs/tutorial/MyFirstLanguageFrontend/index.html
+
+Building
+=========
+
+(1) Install clang and the llvm tool kit.  You can either compile from source
+    (see http://www.llvm.org/docs/GettingStarted.html - or perhaps better,
+    http://clang.llvm.org/get_started.html) or install binaries that you find
+    elsewhere (you SHOULD get LLVM 10.0.0 - No guarantees are made for older
+    OR NEWER versions!).
+
+(2) Run `make` (or perhaps `make clean` and then `make`).
+
+(3) If you wish, run `make tests` to run (almost) all the programs delivered
+    in this colleciton.  The output from `make tests` is very long.
+    Each program can also be tested individually, for example with
+    `make testFibonacci` or `make testModuleMaker` or `make test5` 
+    (read the Makefile to see all alternatives).  
+    **Note**: `make test9` is broken. We know.  
+    That's why it's not included in `make tests`.   
+    Please feel free to fix it. 
+
+Further Reading
+===============
+
+These files are only provided to illustrate how LLVM can be used.  The code from
+the tutorial should be read together with the tutorial.
+
+More information is available:
+
+ * Overview of the LLVM Documentation:
+http://llvm.org/releases/10.0.0/docs/index.html
+ * The LLVM ("Kaledeiscope") Tutorial:
+https://llvm.org/docs/tutorial/MyFirstLanguageFrontend/index.html
+ * Guide for Programmers:
+http://llvm.org/releases/10.0.0/docs/ProgrammersManual.html
+ * Guide to the LLVM IR (LLVM Intermediate Representation):
+http://llvm.org/releases/10.0.0/docs/LangRef.html
+
+
+
+
+
+
+
diff --git a/LLVM/cplusplus/fibonacci.cpp b/LLVM/cplusplus/fibonacci.cpp
new file mode 100644
index 0000000..12393a4
--- /dev/null
+++ b/LLVM/cplusplus/fibonacci.cpp
@@ -0,0 +1,148 @@
+//===--- examples/Fibonacci/fibonacci.cpp - An example use of the JIT -----===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This small program provides an example of how to build quickly a small module
+// with function Fibonacci and execute it with the JIT.
+//
+// The goal of this snippet is to create in the memory the LLVM module
+// consisting of one function as follow:
+//
+//   int fib(int x) {
+//     if(x<=2) return 1;
+//     return fib(x-1)+fib(x-2);
+//   }
+//
+// Once we have this, we compile the module via JIT, then execute the `fib'
+// function and return result to a driver, i.e. to a "host program".
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/APInt.h"
+#include "llvm/IR/Verifier.h"
+#include "llvm/ExecutionEngine/ExecutionEngine.h"
+#include "llvm/ExecutionEngine/GenericValue.h"
+#include "llvm/ExecutionEngine/MCJIT.h"
+#include "llvm/IR/Argument.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/InstrTypes.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Type.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
+#include <cstdlib>
+#include <memory>
+#include <string>
+#include <vector>
+
+using namespace llvm;
+
+static Function *CreateFibFunction(Module *M, LLVMContext &Context) {
+  // Create the fib function and insert it into module M. This function is said
+  // to return an int and take an int parameter.
+  FunctionType *FibFTy = FunctionType::get(Type::getInt32Ty(Context),
+                                           {Type::getInt32Ty(Context)}, false);
+  Function *FibF =
+      Function::Create(FibFTy, Function::ExternalLinkage, "fib", M);
+
+  // Add a basic block to the function.
+  BasicBlock *BB = BasicBlock::Create(Context, "EntryBlock", FibF);
+
+  // Get pointers to the constants.
+  Value *One = ConstantInt::get(Type::getInt32Ty(Context), 1);
+  Value *Two = ConstantInt::get(Type::getInt32Ty(Context), 2);
+
+  // Get pointer to the integer argument of the add1 function...
+  Argument *ArgX = &*FibF->arg_begin(); // Get the arg.
+  ArgX->setName("AnArg");            // Give it a nice symbolic name for fun.
+
+  // Create the true_block.
+  BasicBlock *RetBB = BasicBlock::Create(Context, "return", FibF);
+  // Create an exit block.
+  BasicBlock* RecurseBB = BasicBlock::Create(Context, "recurse", FibF);
+
+  // Create the "if (arg <= 2) goto exitbb"
+  Value *CondInst = new ICmpInst(*BB, ICmpInst::ICMP_SLE, ArgX, Two, "cond");
+  BranchInst::Create(RetBB, RecurseBB, CondInst, BB);
+
+  // Create: ret int 1
+  ReturnInst::Create(Context, One, RetBB);
+
+  // create fib(x-1)
+  Value *Sub = BinaryOperator::CreateSub(ArgX, One, "arg", RecurseBB);
+  CallInst *CallFibX1 = CallInst::Create(FibF, Sub, "fibx1", RecurseBB);
+  CallFibX1->setTailCall();
+
+  // create fib(x-2)
+  Sub = BinaryOperator::CreateSub(ArgX, Two, "arg", RecurseBB);
+  CallInst *CallFibX2 = CallInst::Create(FibF, Sub, "fibx2", RecurseBB);
+  CallFibX2->setTailCall();
+
+  // fib(x-1)+fib(x-2)
+  Value *Sum = BinaryOperator::CreateAdd(CallFibX1, CallFibX2,
+                                         "addresult", RecurseBB);
+
+  // Create the return instruction and add it to the basic block
+  ReturnInst::Create(Context, Sum, RecurseBB);
+
+  return FibF;
+}
+
+int main(int argc, char **argv) {
+  int n = argc > 1 ? atol(argv[1]) : 24;
+
+  InitializeNativeTarget();
+  InitializeNativeTargetAsmPrinter();
+  LLVMContext Context;
+
+  // Create some module to put our function into it.
+  std::unique_ptr<Module> Owner(new Module("test", Context));
+  Module *M = Owner.get();
+
+  // We are about to create the "fib" function:
+  Function *FibF = CreateFibFunction(M, Context);
+
+  // Now we going to create JIT
+  std::string errStr;
+  ExecutionEngine *EE =
+    EngineBuilder(std::move(Owner))
+    .setErrorStr(&errStr)
+    .create();
+
+  if (!EE) {
+    errs() << argv[0] << ": Failed to construct ExecutionEngine: " << errStr
+           << "\n";
+    return 1;
+  }
+
+  errs() << "verifying... ";
+  if (verifyModule(*M)) {
+    errs() << argv[0] << ": Error constructing function!\n";
+    return 1;
+  }
+
+  errs() << "OK\n";
+  errs() << "We just constructed this LLVM module:\n\n---------\n" << *M;
+  errs() << "---------\nstarting fibonacci(" << n << ") with JIT...\n";
+
+  // Call the Fibonacci function with argument n:
+  std::vector<GenericValue> Args(1);
+  Args[0].IntVal = APInt(32, n);
+  GenericValue GV = EE->runFunction(FibF, Args);
+
+  // import result of execution
+  outs() << "Result: " << GV.IntVal << "\n";
+
+  return 0;
+}
diff --git a/LLVM/cplusplus/tests/fibonacci.kal b/LLVM/cplusplus/tests/fibonacci.kal
new file mode 100644
index 0000000..96f27c3
--- /dev/null
+++ b/LLVM/cplusplus/tests/fibonacci.kal
@@ -0,0 +1,9 @@
+# Compute the x'th fibonacci number.
+def fib(x)
+  if x < 3 then
+    1
+  else
+    fib(x-1)+fib(x-2)
+
+# This expression will compute the 40th number.
+fib(40)
diff --git a/LLVM/cplusplus/tests/test2.kal b/LLVM/cplusplus/tests/test2.kal
new file mode 100644
index 0000000..0237059
--- /dev/null
+++ b/LLVM/cplusplus/tests/test2.kal
@@ -0,0 +1,4 @@
+def foo(x y) x+foo(y, 4.0);
+def foo(x y) x+y y;
+def foo(x y) x+y );
+extern sin(a);
diff --git a/LLVM/cplusplus/tests/test3.kal b/LLVM/cplusplus/tests/test3.kal
new file mode 100644
index 0000000..2f36ed8
--- /dev/null
+++ b/LLVM/cplusplus/tests/test3.kal
@@ -0,0 +1,7 @@
+# Compare http://llvm.org/docs/tutorial/LangImpl3.html#driver-changes-and-closing-thoughts
+4+5;
+def foo(a b) a*a + 2*a*b + b*b;
+def bar(a) foo(a, 4.0) + bar(31337);
+extern cos(x);
+cos(1.234);
+
diff --git a/LLVM/cplusplus/tests/test4.kal b/LLVM/cplusplus/tests/test4.kal
new file mode 100644
index 0000000..97a8f96
--- /dev/null
+++ b/LLVM/cplusplus/tests/test4.kal
@@ -0,0 +1,12 @@
+# Compare http://llvm.org/docs/tutorial/LangImpl4.html#adding-a-jit-compiler
+4+5;
+def testfunc(x y) x + y*2;
+testfunc(4, 10);
+extern sin(x);
+extern cos(x);
+sin(1.0);
+def foo(x) sin(x)*sin(x) + cos(x)*cos(x);
+foo(4.0);
+foo(42.0);
+extern putchard(x); 
+putchard(120);
diff --git a/LLVM/cplusplus/tests/test5.kal b/LLVM/cplusplus/tests/test5.kal
new file mode 100644
index 0000000..5faee3b
--- /dev/null
+++ b/LLVM/cplusplus/tests/test5.kal
@@ -0,0 +1,26 @@
+# http://llvm.org/docs/tutorial/LangImpl5.html
+extern foo();
+extern bar();
+def baz(x) if x then foo() else bar();
+#
+def fib(x)
+  if x < 3 then
+    1
+  else
+    fib(x-1)+fib(x-2);
+#
+fib(1);
+fib(2);
+fib(3);
+fib(4);
+fib(10);
+fib(20);
+#
+extern putchard(char)
+def printstar(n)
+  for i = 1, i < n, 1.0 in
+    putchard(42);  # ascii 42 = '*';
+
+# print 100 '*' characters
+printstar(100);
+
diff --git a/LLVM/cplusplus/tests/test6.kal b/LLVM/cplusplus/tests/test6.kal
new file mode 100644
index 0000000..70b2d6d
--- /dev/null
+++ b/LLVM/cplusplus/tests/test6.kal
@@ -0,0 +1,101 @@
+# Cf. http://llvm.org/docs/tutorial/LangImpl6.html#kicking-the-tires
+#
+extern printd(x);
+def binary : 1 (x y) 0;  # Low-precedence operator that ignores operands.
+printd(123) : printd(456) : printd(789);
+
+# Logical unary not.
+def unary!(v)
+  if v then
+    0
+  else
+    1;
+
+# Unary negate.
+def unary-(v)
+  0-v;
+
+# Define > with the same precedence as <.
+def binary> 10 (LHS RHS)
+  RHS < LHS;
+
+# Binary logical or, which does not short circuit.
+def binary| 5 (LHS RHS)
+  if LHS then
+    1
+  else if RHS then
+    1
+  else
+    0;
+
+# Binary logical and, which does not short circuit.
+def binary& 6 (LHS RHS)
+  if !LHS then
+    0
+  else
+    !!RHS;
+
+# Define = with slightly lower precedence than relationals.
+def binary = 9 (LHS RHS)
+  !(LHS < RHS | LHS > RHS);
+
+# Define ':' for sequencing: as a low-precedence operator that ignores operands
+# and just returns the RHS.
+def binary : 1 (x y) y;
+
+
+extern putchard(char)
+def printdensity(d)
+  if d > 8 then
+    putchard(32)  # ' '
+  else if d > 4 then
+    putchard(46)  # '.'
+  else if d > 2 then
+    putchard(43)  # '+'
+  else
+    putchard(42); # '*'
+
+printdensity(1): printdensity(2): printdensity(3):
+printdensity(4): printdensity(5): printdensity(9):
+putchard(10);
+
+# Determine whether the specific location diverges.
+# Solve for z = z^2 + c in the complex plane.
+def mandleconverger(real imag iters creal cimag)
+  if iters > 255 | (real*real + imag*imag > 4) then
+    iters
+  else
+    mandleconverger(real*real - imag*imag + creal,
+                    2*real*imag + cimag,
+                    iters+1, creal, cimag);
+
+# Return the number of iterations required for the iteration to escape
+def mandleconverge(real imag)
+  mandleconverger(real, imag, 0, real, imag);
+
+# Compute and plot the mandlebrot set with the specified 2 dimensional range
+# info.
+def mandelhelp(xmin xmax xstep   ymin ymax ystep)
+  for y = ymin, y < ymax, ystep in (
+    (for x = xmin, x < xmax, xstep in
+       printdensity(mandleconverge(x,y)))
+    : putchard(10)
+  )
+
+# mandel - This is a convenient helper function for plotting the mandelbrot set
+# from the specified position with the specified Magnification.
+def mandel(realstart imagstart realmag imagmag)
+  mandelhelp(realstart, realstart+realmag*78, realmag,
+             imagstart, imagstart+imagmag*40, imagmag);
+
+mandel(-2.3, -1.3, 0.05, 0.07);
+
+mandel(-2, -1, 0.02, 0.04);
+
+mandel(-0.9, -1.4, 0.02, 0.03);
+
+
+
+
+
+
diff --git a/LLVM/cplusplus/tests/test7.kal b/LLVM/cplusplus/tests/test7.kal
new file mode 100644
index 0000000..cda8e39
--- /dev/null
+++ b/LLVM/cplusplus/tests/test7.kal
@@ -0,0 +1,22 @@
+# Define ':' for sequencing: as a low-precedence operator that ignores operands
+# and just returns the RHS.
+def binary : 1 (x y) y;
+
+# Recursive fib, we could do this before.
+def fib(x)
+  if (x < 3) then
+    1
+  else
+    fib(x-1)+fib(x-2);
+
+# Iterative fib.
+def fibi(x)
+  var a = 1, b = 1, c in
+  (for i = 3, i < x in
+     c = a + b :
+     a = b :
+     b = c) :
+  b;
+
+# Call it.
+fibi(10);
diff --git a/LLVM/cplusplus/tests/test8.cpp b/LLVM/cplusplus/tests/test8.cpp
new file mode 100644
index 0000000..4f4539a
--- /dev/null
+++ b/LLVM/cplusplus/tests/test8.cpp
@@ -0,0 +1,9 @@
+#include <iostream>
+
+extern "C" {
+    double average(double, double);
+}
+
+int main() {
+    std::cout << "average of 40.0 and 44.0: " << average(40.0, 44.0) << std::endl;
+}
diff --git a/LLVM/cplusplus/tests/test8.kal b/LLVM/cplusplus/tests/test8.kal
new file mode 100644
index 0000000..da902f4
--- /dev/null
+++ b/LLVM/cplusplus/tests/test8.kal
@@ -0,0 +1 @@
+def average(x y) (x + y) * 0.5;
diff --git a/LLVM/cplusplus/tests/test9.kal b/LLVM/cplusplus/tests/test9.kal
new file mode 100644
index 0000000..bff294a
--- /dev/null
+++ b/LLVM/cplusplus/tests/test9.kal
@@ -0,0 +1,7 @@
+def fib(x)
+  if x < 3 then
+    1
+  else
+    fib(x-1)+fib(x-2)
+
+fib(10)
diff --git a/LLVM/cplusplus/toy2.cpp b/LLVM/cplusplus/toy2.cpp
new file mode 100644
index 0000000..59432fb
--- /dev/null
+++ b/LLVM/cplusplus/toy2.cpp
@@ -0,0 +1,447 @@
+#include "llvm/ADT/STLExtras.h"
+#include <algorithm>
+#include <cctype>
+#include <cstdio>
+#include <cstdlib>
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+//===----------------------------------------------------------------------===//
+// 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
+};
+
+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;
+    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)
+//===----------------------------------------------------------------------===//
+
+namespace {
+
+/// ExprAST - Base class for all expression nodes.
+class ExprAST {
+public:
+  virtual ~ExprAST() = default;
+};
+
+/// NumberExprAST - Expression class for numeric literals like "1.0".
+class NumberExprAST : public ExprAST {
+  double Val;
+
+public:
+  NumberExprAST(double Val) : Val(Val) {}
+};
+
+/// VariableExprAST - Expression class for referencing a variable, like "a".
+class VariableExprAST : public ExprAST {
+  std::string Name;
+
+public:
+  VariableExprAST(const std::string &Name) : Name(Name) {}
+};
+
+/// BinaryExprAST - Expression class for a binary operator.
+class BinaryExprAST : public ExprAST {
+  char Op;
+  std::unique_ptr<ExprAST> LHS, RHS;
+
+public:
+  BinaryExprAST(char Op, std::unique_ptr<ExprAST> LHS,
+                std::unique_ptr<ExprAST> RHS)
+      : Op(Op), LHS(std::move(LHS)), RHS(std::move(RHS)) {}
+};
+
+/// CallExprAST - Expression class for function calls.
+class CallExprAST : public ExprAST {
+  std::string Callee;
+  std::vector<std::unique_ptr<ExprAST>> Args;
+
+public:
+  CallExprAST(const std::string &Callee,
+              std::vector<std::unique_ptr<ExprAST>> Args)
+      : Callee(Callee), Args(std::move(Args)) {}
+};
+
+/// PrototypeAST - This class represents the "prototype" for a function,
+/// which captures its name, and its argument names (thus implicitly the number
+/// of arguments the function takes).
+class PrototypeAST {
+  std::string Name;
+  std::vector<std::string> Args;
+
+public:
+  PrototypeAST(const std::string &Name, std::vector<std::string> Args)
+      : Name(Name), Args(std::move(Args)) {}
+
+  const std::string &getName() const { return Name; }
+};
+
+/// FunctionAST - This class represents a function definition itself.
+class FunctionAST {
+  std::unique_ptr<PrototypeAST> Proto;
+  std::unique_ptr<ExprAST> Body;
+
+public:
+  FunctionAST(std::unique_ptr<PrototypeAST> Proto,
+              std::unique_ptr<ExprAST> Body)
+      : Proto(std::move(Proto)), Body(std::move(Body)) {}
+};
+
+} // end anonymous namespace
+
+//===----------------------------------------------------------------------===//
+// 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;
+}
+
+/// LogError* - These are little helper functions for error handling.
+std::unique_ptr<ExprAST> LogError(const char *Str) {
+  fprintf(stderr, "Error: %s\n", Str);
+  return nullptr;
+}
+std::unique_ptr<PrototypeAST> LogErrorP(const char *Str) {
+  LogError(Str);
+  return nullptr;
+}
+
+static std::unique_ptr<ExprAST> ParseExpression();
+
+/// numberexpr ::= number
+static std::unique_ptr<ExprAST> ParseNumberExpr() {
+  auto Result = std::make_unique<NumberExprAST>(NumVal);
+  getNextToken(); // consume the number
+  return std::move(Result);
+}
+
+/// parenexpr ::= '(' expression ')'
+static std::unique_ptr<ExprAST> ParseParenExpr() {
+  getNextToken(); // eat (.
+  auto V = ParseExpression();
+  if (!V)
+    return nullptr;
+
+  if (CurTok != ')')
+    return LogError("expected ')'");
+  getNextToken(); // eat ).
+  return V;
+}
+
+/// identifierexpr
+///   ::= identifier
+///   ::= identifier '(' expression* ')'
+static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
+  std::string IdName = IdentifierStr;
+
+  getNextToken(); // eat identifier.
+
+  if (CurTok != '(') // Simple variable ref.
+    return std::make_unique<VariableExprAST>(IdName);
+
+  // Call.
+  getNextToken(); // eat (
+  std::vector<std::unique_ptr<ExprAST>> Args;
+  if (CurTok != ')') {
+    while (true) {
+      if (auto Arg = ParseExpression())
+        Args.push_back(std::move(Arg));
+      else
+        return nullptr;
+
+      if (CurTok == ')')
+        break;
+
+      if (CurTok != ',')
+        return LogError("Expected ')' or ',' in argument list");
+      getNextToken();
+    }
+  }
+
+  // Eat the ')'.
+  getNextToken();
+
+  return std::make_unique<CallExprAST>(IdName, std::move(Args));
+}
+
+/// primary
+///   ::= identifierexpr
+///   ::= numberexpr
+///   ::= parenexpr
+static std::unique_ptr<ExprAST> ParsePrimary() {
+  switch (CurTok) {
+  default:
+    return LogError("unknown token when expecting an expression");
+  case tok_identifier:
+    return ParseIdentifierExpr();
+  case tok_number:
+    return ParseNumberExpr();
+  case '(':
+    return ParseParenExpr();
+  }
+}
+
+/// binoprhs
+///   ::= ('+' primary)*
+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 primary expression after the binary operator.
+    auto RHS = ParsePrimary();
+    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 = std::make_unique<BinaryExprAST>(BinOp, std::move(LHS),
+                                           std::move(RHS));
+  }
+}
+
+/// expression
+///   ::= primary binoprhs
+///
+static std::unique_ptr<ExprAST> ParseExpression() {
+  auto LHS = ParsePrimary();
+  if (!LHS)
+    return nullptr;
+
+  return ParseBinOpRHS(0, std::move(LHS));
+}
+
+/// prototype
+///   ::= id '(' id* ')'
+static std::unique_ptr<PrototypeAST> ParsePrototype() {
+  if (CurTok != tok_identifier)
+    return LogErrorP("Expected function name in prototype");
+
+  std::string FnName = IdentifierStr;
+  getNextToken();
+
+  if (CurTok != '(')
+    return LogErrorP("Expected '(' in prototype");
+
+  std::vector<std::string> ArgNames;
+  while (getNextToken() == tok_identifier)
+    ArgNames.push_back(IdentifierStr);
+  if (CurTok != ')')
+    return LogErrorP("Expected ')' in prototype");
+
+  // success.
+  getNextToken(); // eat ')'.
+
+  return std::make_unique<PrototypeAST>(FnName, std::move(ArgNames));
+}
+
+/// definition ::= 'def' prototype expression
+static std::unique_ptr<FunctionAST> ParseDefinition() {
+  getNextToken(); // eat def.
+  auto Proto = ParsePrototype();
+  if (!Proto)
+    return nullptr;
+
+  if (auto E = ParseExpression())
+    return std::make_unique<FunctionAST>(std::move(Proto), std::move(E));
+  return nullptr;
+}
+
+/// toplevelexpr ::= expression
+static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
+  if (auto E = ParseExpression()) {
+    // Make an anonymous proto.
+    auto Proto = std::make_unique<PrototypeAST>("__anon_expr",
+                                                 std::vector<std::string>());
+    return std::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();
+}
+
+//===----------------------------------------------------------------------===//
+// Top-Level parsing
+//===----------------------------------------------------------------------===//
+
+static void HandleDefinition() {
+  if (ParseDefinition()) {
+    fprintf(stderr, "Parsed a function definition.\n");
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+static void HandleExtern() {
+  if (ParseExtern()) {
+    fprintf(stderr, "Parsed an extern\n");
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+static void HandleTopLevelExpression() {
+  // Evaluate a top-level expression into an anonymous function.
+  if (ParseTopLevelExpr()) {
+    fprintf(stderr, "Parsed a top-level expr\n");
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+/// top ::= definition | external | expression | ';'
+static void MainLoop() {
+  while (true) {
+    fprintf(stderr, "ready> ");
+    switch (CurTok) {
+    case tok_eof:
+      return;
+    case ';': // ignore top-level semicolons.
+      getNextToken();
+      break;
+    case tok_def:
+      HandleDefinition();
+      break;
+    case tok_extern:
+      HandleExtern();
+      break;
+    default:
+      HandleTopLevelExpression();
+      break;
+    }
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// Main driver code.
+//===----------------------------------------------------------------------===//
+
+int main() {
+  // Install standard binary operators.
+  // 1 is lowest precedence.
+  BinopPrecedence['<'] = 10;
+  BinopPrecedence['+'] = 20;
+  BinopPrecedence['-'] = 20;
+  BinopPrecedence['*'] = 40; // highest.
+
+  // Prime the first token.
+  fprintf(stderr, "ready> ");
+  getNextToken();
+
+  // Run the main "interpreter loop" now.
+  MainLoop();
+
+  return 0;
+}
diff --git a/LLVM/cplusplus/toy3.cpp b/LLVM/cplusplus/toy3.cpp
new file mode 100644
index 0000000..557780d
--- /dev/null
+++ b/LLVM/cplusplus/toy3.cpp
@@ -0,0 +1,610 @@
+#include "llvm/ADT/APFloat.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Type.h"
+#include "llvm/IR/Verifier.h"
+#include <algorithm>
+#include <cctype>
+#include <cstdio>
+#include <cstdlib>
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+// 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
+};
+
+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;
+    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)
+//===----------------------------------------------------------------------===//
+
+namespace {
+
+/// ExprAST - Base class for all expression nodes.
+class ExprAST {
+public:
+  virtual ~ExprAST() = default;
+
+  virtual Value *codegen() = 0;
+};
+
+/// NumberExprAST - Expression class for numeric literals like "1.0".
+class NumberExprAST : public ExprAST {
+  double Val;
+
+public:
+  NumberExprAST(double Val) : Val(Val) {}
+
+  Value *codegen() override;
+};
+
+/// VariableExprAST - Expression class for referencing a variable, like "a".
+class VariableExprAST : public ExprAST {
+  std::string Name;
+
+public:
+  VariableExprAST(const std::string &Name) : Name(Name) {}
+
+  Value *codegen() override;
+};
+
+/// BinaryExprAST - Expression class for a binary operator.
+class BinaryExprAST : public ExprAST {
+  char Op;
+  std::unique_ptr<ExprAST> LHS, RHS;
+
+public:
+  BinaryExprAST(char Op, std::unique_ptr<ExprAST> LHS,
+                std::unique_ptr<ExprAST> RHS)
+      : Op(Op), LHS(std::move(LHS)), RHS(std::move(RHS)) {}
+
+  Value *codegen() override;
+};
+
+/// CallExprAST - Expression class for function calls.
+class CallExprAST : public ExprAST {
+  std::string Callee;
+  std::vector<std::unique_ptr<ExprAST>> Args;
+
+public:
+  CallExprAST(const std::string &Callee,
+              std::vector<std::unique_ptr<ExprAST>> Args)
+      : Callee(Callee), Args(std::move(Args)) {}
+
+  Value *codegen() override;
+};
+
+/// PrototypeAST - This class represents the "prototype" for a function,
+/// which captures its name, and its argument names (thus implicitly the number
+/// of arguments the function takes).
+class PrototypeAST {
+  std::string Name;
+  std::vector<std::string> Args;
+
+public:
+  PrototypeAST(const std::string &Name, std::vector<std::string> Args)
+      : Name(Name), Args(std::move(Args)) {}
+
+  Function *codegen();
+  const std::string &getName() const { return Name; }
+};
+
+/// FunctionAST - This class represents a function definition itself.
+class FunctionAST {
+  std::unique_ptr<PrototypeAST> Proto;
+  std::unique_ptr<ExprAST> Body;
+
+public:
+  FunctionAST(std::unique_ptr<PrototypeAST> Proto,
+              std::unique_ptr<ExprAST> Body)
+      : Proto(std::move(Proto)), Body(std::move(Body)) {}
+
+  Function *codegen();
+};
+
+} // end anonymous namespace
+
+//===----------------------------------------------------------------------===//
+// 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;
+}
+
+/// LogError* - These are little helper functions for error handling.
+std::unique_ptr<ExprAST> LogError(const char *Str) {
+  fprintf(stderr, "Error: %s\n", Str);
+  return nullptr;
+}
+
+std::unique_ptr<PrototypeAST> LogErrorP(const char *Str) {
+  LogError(Str);
+  return nullptr;
+}
+
+static std::unique_ptr<ExprAST> ParseExpression();
+
+/// numberexpr ::= number
+static std::unique_ptr<ExprAST> ParseNumberExpr() {
+  auto Result = std::make_unique<NumberExprAST>(NumVal);
+  getNextToken(); // consume the number
+  return std::move(Result);
+}
+
+/// parenexpr ::= '(' expression ')'
+static std::unique_ptr<ExprAST> ParseParenExpr() {
+  getNextToken(); // eat (.
+  auto V = ParseExpression();
+  if (!V)
+    return nullptr;
+
+  if (CurTok != ')')
+    return LogError("expected ')'");
+  getNextToken(); // eat ).
+  return V;
+}
+
+/// identifierexpr
+///   ::= identifier
+///   ::= identifier '(' expression* ')'
+static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
+  std::string IdName = IdentifierStr;
+
+  getNextToken(); // eat identifier.
+
+  if (CurTok != '(') // Simple variable ref.
+    return std::make_unique<VariableExprAST>(IdName);
+
+  // Call.
+  getNextToken(); // eat (
+  std::vector<std::unique_ptr<ExprAST>> Args;
+  if (CurTok != ')') {
+    while (true) {
+      if (auto Arg = ParseExpression())
+        Args.push_back(std::move(Arg));
+      else
+        return nullptr;
+
+      if (CurTok == ')')
+        break;
+
+      if (CurTok != ',')
+        return LogError("Expected ')' or ',' in argument list");
+      getNextToken();
+    }
+  }
+
+  // Eat the ')'.
+  getNextToken();
+
+  return std::make_unique<CallExprAST>(IdName, std::move(Args));
+}
+
+/// primary
+///   ::= identifierexpr
+///   ::= numberexpr
+///   ::= parenexpr
+static std::unique_ptr<ExprAST> ParsePrimary() {
+  switch (CurTok) {
+  default:
+    return LogError("unknown token when expecting an expression");
+  case tok_identifier:
+    return ParseIdentifierExpr();
+  case tok_number:
+    return ParseNumberExpr();
+  case '(':
+    return ParseParenExpr();
+  }
+}
+
+/// binoprhs
+///   ::= ('+' primary)*
+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 primary expression after the binary operator.
+    auto RHS = ParsePrimary();
+    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 =
+        std::make_unique<BinaryExprAST>(BinOp, std::move(LHS), std::move(RHS));
+  }
+}
+
+/// expression
+///   ::= primary binoprhs
+///
+static std::unique_ptr<ExprAST> ParseExpression() {
+  auto LHS = ParsePrimary();
+  if (!LHS)
+    return nullptr;
+
+  return ParseBinOpRHS(0, std::move(LHS));
+}
+
+/// prototype
+///   ::= id '(' id* ')'
+static std::unique_ptr<PrototypeAST> ParsePrototype() {
+  if (CurTok != tok_identifier)
+    return LogErrorP("Expected function name in prototype");
+
+  std::string FnName = IdentifierStr;
+  getNextToken();
+
+  if (CurTok != '(')
+    return LogErrorP("Expected '(' in prototype");
+
+  std::vector<std::string> ArgNames;
+  while (getNextToken() == tok_identifier)
+    ArgNames.push_back(IdentifierStr);
+  if (CurTok != ')')
+    return LogErrorP("Expected ')' in prototype");
+
+  // success.
+  getNextToken(); // eat ')'.
+
+  return std::make_unique<PrototypeAST>(FnName, std::move(ArgNames));
+}
+
+/// definition ::= 'def' prototype expression
+static std::unique_ptr<FunctionAST> ParseDefinition() {
+  getNextToken(); // eat def.
+  auto Proto = ParsePrototype();
+  if (!Proto)
+    return nullptr;
+
+  if (auto E = ParseExpression())
+    return std::make_unique<FunctionAST>(std::move(Proto), std::move(E));
+  return nullptr;
+}
+
+/// toplevelexpr ::= expression
+static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
+  if (auto E = ParseExpression()) {
+    // Make an anonymous proto.
+    auto Proto = std::make_unique<PrototypeAST>("__anon_expr",
+                                                 std::vector<std::string>());
+    return std::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
+//===----------------------------------------------------------------------===//
+
+static LLVMContext TheContext;
+static IRBuilder<> Builder(TheContext);
+static std::unique_ptr<Module> TheModule;
+static std::map<std::string, Value *> NamedValues;
+
+Value *LogErrorV(const char *Str) {
+  LogError(Str);
+  return nullptr;
+}
+
+Value *NumberExprAST::codegen() {
+  return ConstantFP::get(TheContext, APFloat(Val));
+}
+
+Value *VariableExprAST::codegen() {
+  // Look this variable up in the function.
+  Value *V = NamedValues[Name];
+  if (!V)
+    return LogErrorV("Unknown variable name");
+  return V;
+}
+
+Value *BinaryExprAST::codegen() {
+  Value *L = LHS->codegen();
+  Value *R = RHS->codegen();
+  if (!L || !R)
+    return nullptr;
+
+  switch (Op) {
+  case '+':
+    return Builder.CreateFAdd(L, R, "addtmp");
+  case '-':
+    return Builder.CreateFSub(L, R, "subtmp");
+  case '*':
+    return Builder.CreateFMul(L, R, "multmp");
+  case '<':
+    L = Builder.CreateFCmpULT(L, R, "cmptmp");
+    // Convert bool 0/1 to double 0.0 or 1.0
+    return Builder.CreateUIToFP(L, Type::getDoubleTy(TheContext), "booltmp");
+  default:
+    return LogErrorV("invalid binary operator");
+  }
+}
+
+Value *CallExprAST::codegen() {
+  // Look up the name in the global module table.
+  Function *CalleeF = TheModule->getFunction(Callee);
+  if (!CalleeF)
+    return LogErrorV("Unknown function referenced");
+
+  // If argument mismatch error.
+  if (CalleeF->arg_size() != Args.size())
+    return LogErrorV("Incorrect # arguments passed");
+
+  std::vector<Value *> ArgsV;
+  for (unsigned i = 0, e = Args.size(); i != e; ++i) {
+    ArgsV.push_back(Args[i]->codegen());
+    if (!ArgsV.back())
+      return nullptr;
+  }
+
+  return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
+}
+
+Function *PrototypeAST::codegen() {
+  // Make the function type:  double(double,double) etc.
+  std::vector<Type *> Doubles(Args.size(), Type::getDoubleTy(TheContext));
+  FunctionType *FT =
+      FunctionType::get(Type::getDoubleTy(TheContext), Doubles, false);
+
+  Function *F =
+      Function::Create(FT, Function::ExternalLinkage, Name, TheModule.get());
+
+  // Set names for all arguments.
+  unsigned Idx = 0;
+  for (auto &Arg : F->args())
+    Arg.setName(Args[Idx++]);
+
+  return F;
+}
+
+Function *FunctionAST::codegen() {
+  // First, check for an existing function from a previous 'extern' declaration.
+  Function *TheFunction = TheModule->getFunction(Proto->getName());
+
+  if (!TheFunction)
+    TheFunction = Proto->codegen();
+
+  if (!TheFunction)
+    return nullptr;
+
+  // Create a new basic block to start insertion into.
+  BasicBlock *BB = BasicBlock::Create(TheContext, "entry", TheFunction);
+  Builder.SetInsertPoint(BB);
+
+  // Record the function arguments in the NamedValues map.
+  NamedValues.clear();
+  for (auto &Arg : TheFunction->args())
+    NamedValues[std::string(Arg.getName())] = &Arg;
+
+  if (Value *RetVal = Body->codegen()) {
+    // Finish off the function.
+    Builder.CreateRet(RetVal);
+
+    // Validate the generated code, checking for consistency.
+    verifyFunction(*TheFunction);
+
+    return TheFunction;
+  }
+
+  // Error reading body, remove function.
+  TheFunction->eraseFromParent();
+  return nullptr;
+}
+
+//===----------------------------------------------------------------------===//
+// Top-Level parsing and JIT Driver
+//===----------------------------------------------------------------------===//
+
+static void HandleDefinition() {
+  if (auto FnAST = ParseDefinition()) {
+    if (auto *FnIR = FnAST->codegen()) {
+      fprintf(stderr, "Read function definition:");
+      FnIR->print(errs());
+      fprintf(stderr, "\n");
+    }
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+static void HandleExtern() {
+  if (auto ProtoAST = ParseExtern()) {
+    if (auto *FnIR = ProtoAST->codegen()) {
+      fprintf(stderr, "Read extern: ");
+      FnIR->print(errs());
+      fprintf(stderr, "\n");
+    }
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+static void HandleTopLevelExpression() {
+  // Evaluate a top-level expression into an anonymous function.
+  if (auto FnAST = ParseTopLevelExpr()) {
+    if (auto *FnIR = FnAST->codegen()) {
+      fprintf(stderr, "Read top-level expression:");
+      FnIR->print(errs());
+      fprintf(stderr, "\n");
+    }
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+/// top ::= definition | external | expression | ';'
+static void MainLoop() {
+  while (true) {
+    fprintf(stderr, "ready> ");
+    switch (CurTok) {
+    case tok_eof:
+      return;
+    case ';': // ignore top-level semicolons.
+      getNextToken();
+      break;
+    case tok_def:
+      HandleDefinition();
+      break;
+    case tok_extern:
+      HandleExtern();
+      break;
+    default:
+      HandleTopLevelExpression();
+      break;
+    }
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// Main driver code.
+//===----------------------------------------------------------------------===//
+
+int main() {
+  // Install standard binary operators.
+  // 1 is lowest precedence.
+  BinopPrecedence['<'] = 10;
+  BinopPrecedence['+'] = 20;
+  BinopPrecedence['-'] = 20;
+  BinopPrecedence['*'] = 40; // highest.
+
+  // Prime the first token.
+  fprintf(stderr, "ready> ");
+  getNextToken();
+
+  // Make the module, which holds all the code.
+  TheModule = std::make_unique<Module>("my cool jit", TheContext);
+
+  // Run the main "interpreter loop" now.
+  MainLoop();
+
+  // Print out all of the generated code.
+  TheModule->print(errs(), nullptr);
+
+  return 0;
+}
diff --git a/LLVM/cplusplus/toy4.cpp b/LLVM/cplusplus/toy4.cpp
new file mode 100644
index 0000000..623b5dc
--- /dev/null
+++ b/LLVM/cplusplus/toy4.cpp
@@ -0,0 +1,701 @@
+// Next Line modified for the FbI/h_da.de version (only)
+#include "KaleidoscopeJIT.h"
+#include "llvm/ADT/APFloat.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/LegacyPassManager.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Type.h"
+#include "llvm/IR/Verifier.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Transforms/InstCombine/InstCombine.h"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Scalar/GVN.h"
+#include <algorithm>
+#include <cassert>
+#include <cctype>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <map>
+#include <memory>
+#include <string>
+#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
+};
+
+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;
+    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)
+//===----------------------------------------------------------------------===//
+
+namespace {
+
+/// ExprAST - Base class for all expression nodes.
+class ExprAST {
+public:
+  virtual ~ExprAST() = default;
+
+  virtual Value *codegen() = 0;
+};
+
+/// NumberExprAST - Expression class for numeric literals like "1.0".
+class NumberExprAST : public ExprAST {
+  double Val;
+
+public:
+  NumberExprAST(double Val) : Val(Val) {}
+
+  Value *codegen() override;
+};
+
+/// VariableExprAST - Expression class for referencing a variable, like "a".
+class VariableExprAST : public ExprAST {
+  std::string Name;
+
+public:
+  VariableExprAST(const std::string &Name) : Name(Name) {}
+
+  Value *codegen() override;
+};
+
+/// BinaryExprAST - Expression class for a binary operator.
+class BinaryExprAST : public ExprAST {
+  char Op;
+  std::unique_ptr<ExprAST> LHS, RHS;
+
+public:
+  BinaryExprAST(char Op, std::unique_ptr<ExprAST> LHS,
+                std::unique_ptr<ExprAST> RHS)
+      : Op(Op), LHS(std::move(LHS)), RHS(std::move(RHS)) {}
+
+  Value *codegen() override;
+};
+
+/// CallExprAST - Expression class for function calls.
+class CallExprAST : public ExprAST {
+  std::string Callee;
+  std::vector<std::unique_ptr<ExprAST>> Args;
+
+public:
+  CallExprAST(const std::string &Callee,
+              std::vector<std::unique_ptr<ExprAST>> Args)
+      : Callee(Callee), Args(std::move(Args)) {}
+
+  Value *codegen() override;
+};
+
+/// PrototypeAST - This class represents the "prototype" for a function,
+/// which captures its name, and its argument names (thus implicitly the number
+/// of arguments the function takes).
+class PrototypeAST {
+  std::string Name;
+  std::vector<std::string> Args;
+
+public:
+  PrototypeAST(const std::string &Name, std::vector<std::string> Args)
+      : Name(Name), Args(std::move(Args)) {}
+
+  Function *codegen();
+  const std::string &getName() const { return Name; }
+};
+
+/// FunctionAST - This class represents a function definition itself.
+class FunctionAST {
+  std::unique_ptr<PrototypeAST> Proto;
+  std::unique_ptr<ExprAST> Body;
+
+public:
+  FunctionAST(std::unique_ptr<PrototypeAST> Proto,
+              std::unique_ptr<ExprAST> Body)
+      : Proto(std::move(Proto)), Body(std::move(Body)) {}
+
+  Function *codegen();
+};
+
+} // end anonymous namespace
+
+//===----------------------------------------------------------------------===//
+// 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;
+}
+
+/// LogError* - These are little helper functions for error handling.
+std::unique_ptr<ExprAST> LogError(const char *Str) {
+  fprintf(stderr, "Error: %s\n", Str);
+  return nullptr;
+}
+
+std::unique_ptr<PrototypeAST> LogErrorP(const char *Str) {
+  LogError(Str);
+  return nullptr;
+}
+
+static std::unique_ptr<ExprAST> ParseExpression();
+
+/// numberexpr ::= number
+static std::unique_ptr<ExprAST> ParseNumberExpr() {
+  auto Result = std::make_unique<NumberExprAST>(NumVal);
+  getNextToken(); // consume the number
+  return std::move(Result);
+}
+
+/// parenexpr ::= '(' expression ')'
+static std::unique_ptr<ExprAST> ParseParenExpr() {
+  getNextToken(); // eat (.
+  auto V = ParseExpression();
+  if (!V)
+    return nullptr;
+
+  if (CurTok != ')')
+    return LogError("expected ')'");
+  getNextToken(); // eat ).
+  return V;
+}
+
+/// identifierexpr
+///   ::= identifier
+///   ::= identifier '(' expression* ')'
+static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
+  std::string IdName = IdentifierStr;
+
+  getNextToken(); // eat identifier.
+
+  if (CurTok != '(') // Simple variable ref.
+    return std::make_unique<VariableExprAST>(IdName);
+
+  // Call.
+  getNextToken(); // eat (
+  std::vector<std::unique_ptr<ExprAST>> Args;
+  if (CurTok != ')') {
+    while (true) {
+      if (auto Arg = ParseExpression())
+        Args.push_back(std::move(Arg));
+      else
+        return nullptr;
+
+      if (CurTok == ')')
+        break;
+
+      if (CurTok != ',')
+        return LogError("Expected ')' or ',' in argument list");
+      getNextToken();
+    }
+  }
+
+  // Eat the ')'.
+  getNextToken();
+
+  return std::make_unique<CallExprAST>(IdName, std::move(Args));
+}
+
+/// primary
+///   ::= identifierexpr
+///   ::= numberexpr
+///   ::= parenexpr
+static std::unique_ptr<ExprAST> ParsePrimary() {
+  switch (CurTok) {
+  default:
+    return LogError("unknown token when expecting an expression");
+  case tok_identifier:
+    return ParseIdentifierExpr();
+  case tok_number:
+    return ParseNumberExpr();
+  case '(':
+    return ParseParenExpr();
+  }
+}
+
+/// binoprhs
+///   ::= ('+' primary)*
+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 primary expression after the binary operator.
+    auto RHS = ParsePrimary();
+    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 =
+        std::make_unique<BinaryExprAST>(BinOp, std::move(LHS), std::move(RHS));
+  }
+}
+
+/// expression
+///   ::= primary binoprhs
+///
+static std::unique_ptr<ExprAST> ParseExpression() {
+  auto LHS = ParsePrimary();
+  if (!LHS)
+    return nullptr;
+
+  return ParseBinOpRHS(0, std::move(LHS));
+}
+
+/// prototype
+///   ::= id '(' id* ')'
+static std::unique_ptr<PrototypeAST> ParsePrototype() {
+  if (CurTok != tok_identifier)
+    return LogErrorP("Expected function name in prototype");
+
+  std::string FnName = IdentifierStr;
+  getNextToken();
+
+  if (CurTok != '(')
+    return LogErrorP("Expected '(' in prototype");
+
+  std::vector<std::string> ArgNames;
+  while (getNextToken() == tok_identifier)
+    ArgNames.push_back(IdentifierStr);
+  if (CurTok != ')')
+    return LogErrorP("Expected ')' in prototype");
+
+  // success.
+  getNextToken(); // eat ')'.
+
+  return std::make_unique<PrototypeAST>(FnName, std::move(ArgNames));
+}
+
+/// definition ::= 'def' prototype expression
+static std::unique_ptr<FunctionAST> ParseDefinition() {
+  getNextToken(); // eat def.
+  auto Proto = ParsePrototype();
+  if (!Proto)
+    return nullptr;
+
+  if (auto E = ParseExpression())
+    return std::make_unique<FunctionAST>(std::move(Proto), std::move(E));
+  return nullptr;
+}
+
+/// toplevelexpr ::= expression
+static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
+  if (auto E = ParseExpression()) {
+    // Make an anonymous proto.
+    auto Proto = std::make_unique<PrototypeAST>("__anon_expr",
+                                                 std::vector<std::string>());
+    return std::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
+//===----------------------------------------------------------------------===//
+
+static LLVMContext TheContext;
+static IRBuilder<> Builder(TheContext);
+static std::unique_ptr<Module> TheModule;
+static std::map<std::string, Value *> NamedValues;
+static std::unique_ptr<legacy::FunctionPassManager> TheFPM;
+static std::unique_ptr<KaleidoscopeJIT> TheJIT;
+static std::map<std::string, std::unique_ptr<PrototypeAST>> FunctionProtos;
+
+Value *LogErrorV(const char *Str) {
+  LogError(Str);
+  return nullptr;
+}
+
+Function *getFunction(std::string Name) {
+  // First, see if the function has already been added to the current module.
+  if (auto *F = TheModule->getFunction(Name))
+    return F;
+
+  // If not, check whether we can codegen the declaration from some existing
+  // prototype.
+  auto FI = FunctionProtos.find(Name);
+  if (FI != FunctionProtos.end())
+    return FI->second->codegen();
+
+  // If no existing prototype exists, return null.
+  return nullptr;
+}
+
+Value *NumberExprAST::codegen() {
+  return ConstantFP::get(TheContext, APFloat(Val));
+}
+
+Value *VariableExprAST::codegen() {
+  // Look this variable up in the function.
+  Value *V = NamedValues[Name];
+  if (!V)
+    return LogErrorV("Unknown variable name");
+  return V;
+}
+
+Value *BinaryExprAST::codegen() {
+  Value *L = LHS->codegen();
+  Value *R = RHS->codegen();
+  if (!L || !R)
+    return nullptr;
+
+  switch (Op) {
+  case '+':
+    return Builder.CreateFAdd(L, R, "addtmp");
+  case '-':
+    return Builder.CreateFSub(L, R, "subtmp");
+  case '*':
+    return Builder.CreateFMul(L, R, "multmp");
+  case '<':
+    L = Builder.CreateFCmpULT(L, R, "cmptmp");
+    // Convert bool 0/1 to double 0.0 or 1.0
+    return Builder.CreateUIToFP(L, Type::getDoubleTy(TheContext), "booltmp");
+  default:
+    return LogErrorV("invalid binary operator");
+  }
+}
+
+Value *CallExprAST::codegen() {
+  // Look up the name in the global module table.
+  Function *CalleeF = getFunction(Callee);
+  if (!CalleeF)
+    return LogErrorV("Unknown function referenced");
+
+  // If argument mismatch error.
+  if (CalleeF->arg_size() != Args.size())
+    return LogErrorV("Incorrect # arguments passed");
+
+  std::vector<Value *> ArgsV;
+  for (unsigned i = 0, e = Args.size(); i != e; ++i) {
+    ArgsV.push_back(Args[i]->codegen());
+    if (!ArgsV.back())
+      return nullptr;
+  }
+
+  return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
+}
+
+Function *PrototypeAST::codegen() {
+  // Make the function type:  double(double,double) etc.
+  std::vector<Type *> Doubles(Args.size(), Type::getDoubleTy(TheContext));
+  FunctionType *FT =
+      FunctionType::get(Type::getDoubleTy(TheContext), Doubles, false);
+
+  Function *F =
+      Function::Create(FT, Function::ExternalLinkage, Name, TheModule.get());
+
+  // Set names for all arguments.
+  unsigned Idx = 0;
+  for (auto &Arg : F->args())
+    Arg.setName(Args[Idx++]);
+
+  return F;
+}
+
+Function *FunctionAST::codegen() {
+  // Transfer ownership of the prototype to the FunctionProtos map, but keep a
+  // reference to it for use below.
+  auto &P = *Proto;
+  FunctionProtos[Proto->getName()] = std::move(Proto);
+  Function *TheFunction = getFunction(P.getName());
+  if (!TheFunction)
+    return nullptr;
+
+  // Create a new basic block to start insertion into.
+  BasicBlock *BB = BasicBlock::Create(TheContext, "entry", TheFunction);
+  Builder.SetInsertPoint(BB);
+
+  // Record the function arguments in the NamedValues map.
+  NamedValues.clear();
+  for (auto &Arg : TheFunction->args())
+    NamedValues[std::string(Arg.getName())] = &Arg;
+
+  if (Value *RetVal = Body->codegen()) {
+    // Finish off the function.
+    Builder.CreateRet(RetVal);
+
+    // Validate the generated code, checking for consistency.
+    verifyFunction(*TheFunction);
+
+    // Run the optimizer on the function.
+    TheFPM->run(*TheFunction);
+
+    return TheFunction;
+  }
+
+  // Error reading body, remove function.
+  TheFunction->eraseFromParent();
+  return nullptr;
+}
+
+//===----------------------------------------------------------------------===//
+// Top-Level parsing and JIT Driver
+//===----------------------------------------------------------------------===//
+
+static void InitializeModuleAndPassManager() {
+  // Open a new module.
+  TheModule = std::make_unique<Module>("my cool jit", TheContext);
+  TheModule->setDataLayout(TheJIT->getTargetMachine().createDataLayout());
+
+  // Create a new pass manager attached to it.
+  TheFPM = std::make_unique<legacy::FunctionPassManager>(TheModule.get());
+
+  // Do simple "peephole" optimizations and bit-twiddling optzns.
+  TheFPM->add(createInstructionCombiningPass());
+  // Reassociate expressions.
+  TheFPM->add(createReassociatePass());
+  // Eliminate Common SubExpressions.
+  TheFPM->add(createGVNPass());
+  // Simplify the control flow graph (deleting unreachable blocks, etc).
+  TheFPM->add(createCFGSimplificationPass());
+
+  TheFPM->doInitialization();
+}
+
+static void HandleDefinition() {
+  if (auto FnAST = ParseDefinition()) {
+    if (auto *FnIR = FnAST->codegen()) {
+      fprintf(stderr, "Read function definition:");
+      FnIR->print(errs());
+      fprintf(stderr, "\n");
+      TheJIT->addModule(std::move(TheModule));
+      InitializeModuleAndPassManager();
+    }
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+static void HandleExtern() {
+  if (auto ProtoAST = ParseExtern()) {
+    if (auto *FnIR = ProtoAST->codegen()) {
+      fprintf(stderr, "Read extern: ");
+      FnIR->print(errs());
+      fprintf(stderr, "\n");
+      FunctionProtos[ProtoAST->getName()] = std::move(ProtoAST);
+    }
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+static void HandleTopLevelExpression() {
+  // Evaluate a top-level expression into an anonymous function.
+  if (auto FnAST = ParseTopLevelExpr()) {
+    if (FnAST->codegen()) {
+      // JIT the module containing the anonymous expression, keeping a handle so
+      // we can free it later.
+      auto H = TheJIT->addModule(std::move(TheModule));
+      InitializeModuleAndPassManager();
+
+      // Search the JIT for the __anon_expr symbol.
+      auto ExprSymbol = TheJIT->findSymbol("__anon_expr");
+      assert(ExprSymbol && "Function not found");
+
+      // Get the symbol's address and 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)cantFail(ExprSymbol.getAddress());
+      fprintf(stderr, "Evaluated to %f\n", FP());
+
+      // Delete the anonymous expression module from the JIT.
+      TheJIT->removeModule(H);
+    }
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+/// top ::= definition | external | expression | ';'
+static void MainLoop() {
+  while (true) {
+    fprintf(stderr, "ready> ");
+    switch (CurTok) {
+    case tok_eof:
+      return;
+    case ';': // ignore top-level semicolons.
+      getNextToken();
+      break;
+    case tok_def:
+      HandleDefinition();
+      break;
+    case tok_extern:
+      HandleExtern();
+      break;
+    default:
+      HandleTopLevelExpression();
+      break;
+    }
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// "Library" functions that can be "extern'd" from user code.
+//===----------------------------------------------------------------------===//
+
+#ifdef _WIN32
+#define DLLEXPORT __declspec(dllexport)
+#else
+#define DLLEXPORT
+#endif
+
+/// putchard - putchar that takes a double and returns 0.
+extern "C" DLLEXPORT double putchard(double X) {
+  fputc((char)X, stderr);
+  return 0;
+}
+
+/// printd - printf that takes a double prints it as "%f\n", returning 0.
+extern "C" DLLEXPORT double printd(double X) {
+  fprintf(stderr, "%f\n", X);
+  return 0;
+}
+
+//===----------------------------------------------------------------------===//
+// Main driver code.
+//===----------------------------------------------------------------------===//
+
+int main() {
+  InitializeNativeTarget();
+  InitializeNativeTargetAsmPrinter();
+  InitializeNativeTargetAsmParser();
+
+  // Install standard binary operators.
+  // 1 is lowest precedence.
+  BinopPrecedence['<'] = 10;
+  BinopPrecedence['+'] = 20;
+  BinopPrecedence['-'] = 20;
+  BinopPrecedence['*'] = 40; // highest.
+
+  // Prime the first token.
+  fprintf(stderr, "ready> ");
+  getNextToken();
+
+  TheJIT = std::make_unique<KaleidoscopeJIT>();
+
+  InitializeModuleAndPassManager();
+
+  // Run the main "interpreter loop" now.
+  MainLoop();
+
+  return 0;
+}
diff --git a/LLVM/cplusplus/toy5.cpp b/LLVM/cplusplus/toy5.cpp
new file mode 100644
index 0000000..7264b80
--- /dev/null
+++ b/LLVM/cplusplus/toy5.cpp
@@ -0,0 +1,975 @@
+// Next Line modified for the FbI/h_da.de version (only)
+#include "KaleidoscopeJIT.h"
+#include "llvm/ADT/APFloat.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/LegacyPassManager.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Type.h"
+#include "llvm/IR/Verifier.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Transforms/InstCombine/InstCombine.h"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Scalar/GVN.h"
+#include <algorithm>
+#include <cassert>
+#include <cctype>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <map>
+#include <memory>
+#include <string>
+#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
+};
+
+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;
+    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)
+//===----------------------------------------------------------------------===//
+
+namespace {
+
+/// ExprAST - Base class for all expression nodes.
+class ExprAST {
+public:
+  virtual ~ExprAST() = default;
+
+  virtual Value *codegen() = 0;
+};
+
+/// NumberExprAST - Expression class for numeric literals like "1.0".
+class NumberExprAST : public ExprAST {
+  double Val;
+
+public:
+  NumberExprAST(double Val) : Val(Val) {}
+
+  Value *codegen() override;
+};
+
+/// VariableExprAST - Expression class for referencing a variable, like "a".
+class VariableExprAST : public ExprAST {
+  std::string Name;
+
+public:
+  VariableExprAST(const std::string &Name) : Name(Name) {}
+
+  Value *codegen() override;
+};
+
+/// BinaryExprAST - Expression class for a binary operator.
+class BinaryExprAST : public ExprAST {
+  char Op;
+  std::unique_ptr<ExprAST> LHS, RHS;
+
+public:
+  BinaryExprAST(char Op, std::unique_ptr<ExprAST> LHS,
+                std::unique_ptr<ExprAST> RHS)
+      : Op(Op), LHS(std::move(LHS)), RHS(std::move(RHS)) {}
+
+  Value *codegen() override;
+};
+
+/// CallExprAST - Expression class for function calls.
+class CallExprAST : public ExprAST {
+  std::string Callee;
+  std::vector<std::unique_ptr<ExprAST>> Args;
+
+public:
+  CallExprAST(const std::string &Callee,
+              std::vector<std::unique_ptr<ExprAST>> Args)
+      : Callee(Callee), Args(std::move(Args)) {}
+
+  Value *codegen() override;
+};
+
+/// IfExprAST - Expression class for if/then/else.
+class IfExprAST : public ExprAST {
+  std::unique_ptr<ExprAST> Cond, Then, Else;
+
+public:
+  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 *codegen() override;
+};
+
+/// ForExprAST - Expression class for for/in.
+class ForExprAST : public ExprAST {
+  std::string VarName;
+  std::unique_ptr<ExprAST> Start, End, Step, Body;
+
+public:
+  ForExprAST(const std::string &VarName, std::unique_ptr<ExprAST> Start,
+             std::unique_ptr<ExprAST> End, std::unique_ptr<ExprAST> Step,
+             std::unique_ptr<ExprAST> Body)
+      : VarName(VarName), Start(std::move(Start)), End(std::move(End)),
+        Step(std::move(Step)), Body(std::move(Body)) {}
+
+  Value *codegen() override;
+};
+
+/// PrototypeAST - This class represents the "prototype" for a function,
+/// which captures its name, and its argument names (thus implicitly the number
+/// of arguments the function takes).
+class PrototypeAST {
+  std::string Name;
+  std::vector<std::string> Args;
+
+public:
+  PrototypeAST(const std::string &Name, std::vector<std::string> Args)
+      : Name(Name), Args(std::move(Args)) {}
+
+  Function *codegen();
+  const std::string &getName() const { return Name; }
+};
+
+/// FunctionAST - This class represents a function definition itself.
+class FunctionAST {
+  std::unique_ptr<PrototypeAST> Proto;
+  std::unique_ptr<ExprAST> Body;
+
+public:
+  FunctionAST(std::unique_ptr<PrototypeAST> Proto,
+              std::unique_ptr<ExprAST> Body)
+      : Proto(std::move(Proto)), Body(std::move(Body)) {}
+
+  Function *codegen();
+};
+
+} // end anonymous namespace
+
+//===----------------------------------------------------------------------===//
+// 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;
+}
+
+/// LogError* - These are little helper functions for error handling.
+std::unique_ptr<ExprAST> LogError(const char *Str) {
+  fprintf(stderr, "Error: %s\n", Str);
+  return nullptr;
+}
+
+std::unique_ptr<PrototypeAST> LogErrorP(const char *Str) {
+  LogError(Str);
+  return nullptr;
+}
+
+static std::unique_ptr<ExprAST> ParseExpression();
+
+/// numberexpr ::= number
+static std::unique_ptr<ExprAST> ParseNumberExpr() {
+  auto Result = std::make_unique<NumberExprAST>(NumVal);
+  getNextToken(); // consume the number
+  return std::move(Result);
+}
+
+/// parenexpr ::= '(' expression ')'
+static std::unique_ptr<ExprAST> ParseParenExpr() {
+  getNextToken(); // eat (.
+  auto V = ParseExpression();
+  if (!V)
+    return nullptr;
+
+  if (CurTok != ')')
+    return LogError("expected ')'");
+  getNextToken(); // eat ).
+  return V;
+}
+
+/// identifierexpr
+///   ::= identifier
+///   ::= identifier '(' expression* ')'
+static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
+  std::string IdName = IdentifierStr;
+
+  getNextToken(); // eat identifier.
+
+  if (CurTok != '(') // Simple variable ref.
+    return std::make_unique<VariableExprAST>(IdName);
+
+  // Call.
+  getNextToken(); // eat (
+  std::vector<std::unique_ptr<ExprAST>> Args;
+  if (CurTok != ')') {
+    while (true) {
+      if (auto Arg = ParseExpression())
+        Args.push_back(std::move(Arg));
+      else
+        return nullptr;
+
+      if (CurTok == ')')
+        break;
+
+      if (CurTok != ',')
+        return LogError("Expected ')' or ',' in argument list");
+      getNextToken();
+    }
+  }
+
+  // Eat the ')'.
+  getNextToken();
+
+  return std::make_unique<CallExprAST>(IdName, std::move(Args));
+}
+
+/// 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 LogError("expected then");
+  getNextToken(); // eat the then
+
+  auto Then = ParseExpression();
+  if (!Then)
+    return nullptr;
+
+  if (CurTok != tok_else)
+    return LogError("expected else");
+
+  getNextToken();
+
+  auto Else = ParseExpression();
+  if (!Else)
+    return nullptr;
+
+  return std::make_unique<IfExprAST>(std::move(Cond), std::move(Then),
+                                      std::move(Else));
+}
+
+/// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression
+static std::unique_ptr<ExprAST> ParseForExpr() {
+  getNextToken(); // eat the for.
+
+  if (CurTok != tok_identifier)
+    return LogError("expected identifier after for");
+
+  std::string IdName = IdentifierStr;
+  getNextToken(); // eat identifier.
+
+  if (CurTok != '=')
+    return LogError("expected '=' after for");
+  getNextToken(); // eat '='.
+
+  auto Start = ParseExpression();
+  if (!Start)
+    return nullptr;
+  if (CurTok != ',')
+    return LogError("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 LogError("expected 'in' after for");
+  getNextToken(); // eat 'in'.
+
+  auto Body = ParseExpression();
+  if (!Body)
+    return nullptr;
+
+  return std::make_unique<ForExprAST>(IdName, std::move(Start), std::move(End),
+                                       std::move(Step), std::move(Body));
+}
+
+/// primary
+///   ::= identifierexpr
+///   ::= numberexpr
+///   ::= parenexpr
+///   ::= ifexpr
+///   ::= forexpr
+static std::unique_ptr<ExprAST> ParsePrimary() {
+  switch (CurTok) {
+  default:
+    return LogError("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();
+  }
+}
+
+/// binoprhs
+///   ::= ('+' primary)*
+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 primary expression after the binary operator.
+    auto RHS = ParsePrimary();
+    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 =
+        std::make_unique<BinaryExprAST>(BinOp, std::move(LHS), std::move(RHS));
+  }
+}
+
+/// expression
+///   ::= primary binoprhs
+///
+static std::unique_ptr<ExprAST> ParseExpression() {
+  auto LHS = ParsePrimary();
+  if (!LHS)
+    return nullptr;
+
+  return ParseBinOpRHS(0, std::move(LHS));
+}
+
+/// prototype
+///   ::= id '(' id* ')'
+static std::unique_ptr<PrototypeAST> ParsePrototype() {
+  if (CurTok != tok_identifier)
+    return LogErrorP("Expected function name in prototype");
+
+  std::string FnName = IdentifierStr;
+  getNextToken();
+
+  if (CurTok != '(')
+    return LogErrorP("Expected '(' in prototype");
+
+  std::vector<std::string> ArgNames;
+  while (getNextToken() == tok_identifier)
+    ArgNames.push_back(IdentifierStr);
+  if (CurTok != ')')
+    return LogErrorP("Expected ')' in prototype");
+
+  // success.
+  getNextToken(); // eat ')'.
+
+  return std::make_unique<PrototypeAST>(FnName, std::move(ArgNames));
+}
+
+/// definition ::= 'def' prototype expression
+static std::unique_ptr<FunctionAST> ParseDefinition() {
+  getNextToken(); // eat def.
+  auto Proto = ParsePrototype();
+  if (!Proto)
+    return nullptr;
+
+  if (auto E = ParseExpression())
+    return std::make_unique<FunctionAST>(std::move(Proto), std::move(E));
+  return nullptr;
+}
+
+/// toplevelexpr ::= expression
+static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
+  if (auto E = ParseExpression()) {
+    // Make an anonymous proto.
+    auto Proto = std::make_unique<PrototypeAST>("__anon_expr",
+                                                 std::vector<std::string>());
+    return std::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
+//===----------------------------------------------------------------------===//
+
+static LLVMContext TheContext;
+static IRBuilder<> Builder(TheContext);
+static std::unique_ptr<Module> TheModule;
+static std::map<std::string, Value *> NamedValues;
+static std::unique_ptr<legacy::FunctionPassManager> TheFPM;
+static std::unique_ptr<KaleidoscopeJIT> TheJIT;
+static std::map<std::string, std::unique_ptr<PrototypeAST>> FunctionProtos;
+
+Value *LogErrorV(const char *Str) {
+  LogError(Str);
+  return nullptr;
+}
+
+Function *getFunction(std::string Name) {
+  // First, see if the function has already been added to the current module.
+  if (auto *F = TheModule->getFunction(Name))
+    return F;
+
+  // If not, check whether we can codegen the declaration from some existing
+  // prototype.
+  auto FI = FunctionProtos.find(Name);
+  if (FI != FunctionProtos.end())
+    return FI->second->codegen();
+
+  // If no existing prototype exists, return null.
+  return nullptr;
+}
+
+Value *NumberExprAST::codegen() {
+  return ConstantFP::get(TheContext, APFloat(Val));
+}
+
+Value *VariableExprAST::codegen() {
+  // Look this variable up in the function.
+  Value *V = NamedValues[Name];
+  if (!V)
+    return LogErrorV("Unknown variable name");
+  return V;
+}
+
+Value *BinaryExprAST::codegen() {
+  Value *L = LHS->codegen();
+  Value *R = RHS->codegen();
+  if (!L || !R)
+    return nullptr;
+
+  switch (Op) {
+  case '+':
+    return Builder.CreateFAdd(L, R, "addtmp");
+  case '-':
+    return Builder.CreateFSub(L, R, "subtmp");
+  case '*':
+    return Builder.CreateFMul(L, R, "multmp");
+  case '<':
+    L = Builder.CreateFCmpULT(L, R, "cmptmp");
+    // Convert bool 0/1 to double 0.0 or 1.0
+    return Builder.CreateUIToFP(L, Type::getDoubleTy(TheContext), "booltmp");
+  default:
+    return LogErrorV("invalid binary operator");
+  }
+}
+
+Value *CallExprAST::codegen() {
+  // Look up the name in the global module table.
+  Function *CalleeF = getFunction(Callee);
+  if (!CalleeF)
+    return LogErrorV("Unknown function referenced");
+
+  // If argument mismatch error.
+  if (CalleeF->arg_size() != Args.size())
+    return LogErrorV("Incorrect # arguments passed");
+
+  std::vector<Value *> ArgsV;
+  for (unsigned i = 0, e = Args.size(); i != e; ++i) {
+    ArgsV.push_back(Args[i]->codegen());
+    if (!ArgsV.back())
+      return nullptr;
+  }
+
+  return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
+}
+
+Value *IfExprAST::codegen() {
+  Value *CondV = Cond->codegen();
+  if (!CondV)
+    return nullptr;
+
+  // Convert condition to a bool by comparing non-equal to 0.0.
+  CondV = Builder.CreateFCmpONE(
+      CondV, ConstantFP::get(TheContext, APFloat(0.0)), "ifcond");
+
+  Function *TheFunction = Builder.GetInsertBlock()->getParent();
+
+  // Create blocks for the then and else cases.  Insert the 'then' block at the
+  // end of the function.
+  BasicBlock *ThenBB = BasicBlock::Create(TheContext, "then", TheFunction);
+  BasicBlock *ElseBB = BasicBlock::Create(TheContext, "else");
+  BasicBlock *MergeBB = BasicBlock::Create(TheContext, "ifcont");
+
+  Builder.CreateCondBr(CondV, ThenBB, ElseBB);
+
+  // Emit then value.
+  Builder.SetInsertPoint(ThenBB);
+
+  Value *ThenV = Then->codegen();
+  if (!ThenV)
+    return nullptr;
+
+  Builder.CreateBr(MergeBB);
+  // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
+  ThenBB = Builder.GetInsertBlock();
+
+  // Emit else block.
+  TheFunction->getBasicBlockList().push_back(ElseBB);
+  Builder.SetInsertPoint(ElseBB);
+
+  Value *ElseV = Else->codegen();
+  if (!ElseV)
+    return nullptr;
+
+  Builder.CreateBr(MergeBB);
+  // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
+  ElseBB = Builder.GetInsertBlock();
+
+  // Emit merge block.
+  TheFunction->getBasicBlockList().push_back(MergeBB);
+  Builder.SetInsertPoint(MergeBB);
+  PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(TheContext), 2, "iftmp");
+
+  PN->addIncoming(ThenV, ThenBB);
+  PN->addIncoming(ElseV, ElseBB);
+  return PN;
+}
+
+// Output for-loop as:
+//   ...
+//   start = startexpr
+//   goto loop
+// loop:
+//   variable = phi [start, loopheader], [nextvariable, loopend]
+//   ...
+//   bodyexpr
+//   ...
+// loopend:
+//   step = stepexpr
+//   nextvariable = variable + step
+//   endcond = endexpr
+//   br endcond, loop, endloop
+// outloop:
+Value *ForExprAST::codegen() {
+  // Emit the start code first, without 'variable' in scope.
+  Value *StartVal = Start->codegen();
+  if (!StartVal)
+    return nullptr;
+
+  // Make the new basic block for the loop header, inserting after current
+  // block.
+  Function *TheFunction = Builder.GetInsertBlock()->getParent();
+  BasicBlock *PreheaderBB = Builder.GetInsertBlock();
+  BasicBlock *LoopBB = BasicBlock::Create(TheContext, "loop", TheFunction);
+
+  // Insert an explicit fall through from the current block to the LoopBB.
+  Builder.CreateBr(LoopBB);
+
+  // Start insertion in LoopBB.
+  Builder.SetInsertPoint(LoopBB);
+
+  // Start the PHI node with an entry for Start.
+  PHINode *Variable =
+      Builder.CreatePHI(Type::getDoubleTy(TheContext), 2, VarName);
+  Variable->addIncoming(StartVal, PreheaderBB);
+
+  // 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.
+  Value *OldVal = NamedValues[VarName];
+  NamedValues[VarName] = Variable;
+
+  // 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->codegen())
+    return nullptr;
+
+  // Emit the step value.
+  Value *StepVal = nullptr;
+  if (Step) {
+    StepVal = Step->codegen();
+    if (!StepVal)
+      return nullptr;
+  } else {
+    // If not specified, use 1.0.
+    StepVal = ConstantFP::get(TheContext, APFloat(1.0));
+  }
+
+  Value *NextVar = Builder.CreateFAdd(Variable, StepVal, "nextvar");
+
+  // Compute the end condition.
+  Value *EndCond = End->codegen();
+  if (!EndCond)
+    return nullptr;
+
+  // Convert condition to a bool by comparing non-equal to 0.0.
+  EndCond = Builder.CreateFCmpONE(
+      EndCond, ConstantFP::get(TheContext, APFloat(0.0)), "loopcond");
+
+  // Create the "after loop" block and insert it.
+  BasicBlock *LoopEndBB = Builder.GetInsertBlock();
+  BasicBlock *AfterBB =
+      BasicBlock::Create(TheContext, "afterloop", TheFunction);
+
+  // Insert the conditional branch into the end of LoopEndBB.
+  Builder.CreateCondBr(EndCond, LoopBB, AfterBB);
+
+  // Any new code will be inserted in AfterBB.
+  Builder.SetInsertPoint(AfterBB);
+
+  // Add a new entry to the PHI node for the backedge.
+  Variable->addIncoming(NextVar, LoopEndBB);
+
+  // Restore the unshadowed variable.
+  if (OldVal)
+    NamedValues[VarName] = OldVal;
+  else
+    NamedValues.erase(VarName);
+
+  // for expr always returns 0.0.
+  return Constant::getNullValue(Type::getDoubleTy(TheContext));
+}
+
+Function *PrototypeAST::codegen() {
+  // Make the function type:  double(double,double) etc.
+  std::vector<Type *> Doubles(Args.size(), Type::getDoubleTy(TheContext));
+  FunctionType *FT =
+      FunctionType::get(Type::getDoubleTy(TheContext), Doubles, false);
+
+  Function *F =
+      Function::Create(FT, Function::ExternalLinkage, Name, TheModule.get());
+
+  // Set names for all arguments.
+  unsigned Idx = 0;
+  for (auto &Arg : F->args())
+    Arg.setName(Args[Idx++]);
+
+  return F;
+}
+
+Function *FunctionAST::codegen() {
+  // Transfer ownership of the prototype to the FunctionProtos map, but keep a
+  // reference to it for use below.
+  auto &P = *Proto;
+  FunctionProtos[Proto->getName()] = std::move(Proto);
+  Function *TheFunction = getFunction(P.getName());
+  if (!TheFunction)
+    return nullptr;
+
+  // Create a new basic block to start insertion into.
+  BasicBlock *BB = BasicBlock::Create(TheContext, "entry", TheFunction);
+  Builder.SetInsertPoint(BB);
+
+  // Record the function arguments in the NamedValues map.
+  NamedValues.clear();
+  for (auto &Arg : TheFunction->args())
+    NamedValues[std::string(Arg.getName())] = &Arg;
+
+  if (Value *RetVal = Body->codegen()) {
+    // Finish off the function.
+    Builder.CreateRet(RetVal);
+
+    // Validate the generated code, checking for consistency.
+    verifyFunction(*TheFunction);
+
+    // Run the optimizer on the function.
+    TheFPM->run(*TheFunction);
+
+    return TheFunction;
+  }
+
+  // Error reading body, remove function.
+  TheFunction->eraseFromParent();
+  return nullptr;
+}
+
+//===----------------------------------------------------------------------===//
+// Top-Level parsing and JIT Driver
+//===----------------------------------------------------------------------===//
+
+static void InitializeModuleAndPassManager() {
+  // Open a new module.
+  TheModule = std::make_unique<Module>("my cool jit", TheContext);
+  TheModule->setDataLayout(TheJIT->getTargetMachine().createDataLayout());
+
+  // Create a new pass manager attached to it.
+  TheFPM = std::make_unique<legacy::FunctionPassManager>(TheModule.get());
+
+  // Do simple "peephole" optimizations and bit-twiddling optzns.
+  TheFPM->add(createInstructionCombiningPass());
+  // Reassociate expressions.
+  TheFPM->add(createReassociatePass());
+  // Eliminate Common SubExpressions.
+  TheFPM->add(createGVNPass());
+  // Simplify the control flow graph (deleting unreachable blocks, etc).
+  TheFPM->add(createCFGSimplificationPass());
+
+  TheFPM->doInitialization();
+}
+
+static void HandleDefinition() {
+  if (auto FnAST = ParseDefinition()) {
+    if (auto *FnIR = FnAST->codegen()) {
+      fprintf(stderr, "Read function definition:");
+      FnIR->print(errs());
+      fprintf(stderr, "\n");
+      TheJIT->addModule(std::move(TheModule));
+      InitializeModuleAndPassManager();
+    }
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+static void HandleExtern() {
+  if (auto ProtoAST = ParseExtern()) {
+    if (auto *FnIR = ProtoAST->codegen()) {
+      fprintf(stderr, "Read extern: ");
+      FnIR->print(errs());
+      fprintf(stderr, "\n");
+      FunctionProtos[ProtoAST->getName()] = std::move(ProtoAST);
+    }
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+static void HandleTopLevelExpression() {
+  // Evaluate a top-level expression into an anonymous function.
+  if (auto FnAST = ParseTopLevelExpr()) {
+    if (FnAST->codegen()) {
+      // JIT the module containing the anonymous expression, keeping a handle so
+      // we can free it later.
+      auto H = TheJIT->addModule(std::move(TheModule));
+      InitializeModuleAndPassManager();
+
+      // Search the JIT for the __anon_expr symbol.
+      auto ExprSymbol = TheJIT->findSymbol("__anon_expr");
+      assert(ExprSymbol && "Function not found");
+
+      // Get the symbol's address and 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)cantFail(ExprSymbol.getAddress());
+      fprintf(stderr, "Evaluated to %f\n", FP());
+
+      // Delete the anonymous expression module from the JIT.
+      TheJIT->removeModule(H);
+    }
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+/// top ::= definition | external | expression | ';'
+static void MainLoop() {
+  while (true) {
+    fprintf(stderr, "ready> ");
+    switch (CurTok) {
+    case tok_eof:
+      return;
+    case ';': // ignore top-level semicolons.
+      getNextToken();
+      break;
+    case tok_def:
+      HandleDefinition();
+      break;
+    case tok_extern:
+      HandleExtern();
+      break;
+    default:
+      HandleTopLevelExpression();
+      break;
+    }
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// "Library" functions that can be "extern'd" from user code.
+//===----------------------------------------------------------------------===//
+
+#ifdef _WIN32
+#define DLLEXPORT __declspec(dllexport)
+#else
+#define DLLEXPORT
+#endif
+
+/// putchard - putchar that takes a double and returns 0.
+extern "C" DLLEXPORT double putchard(double X) {
+  fputc((char)X, stderr);
+  return 0;
+}
+
+/// printd - printf that takes a double prints it as "%f\n", returning 0.
+extern "C" DLLEXPORT double printd(double X) {
+  fprintf(stderr, "%f\n", X);
+  return 0;
+}
+
+//===----------------------------------------------------------------------===//
+// Main driver code.
+//===----------------------------------------------------------------------===//
+
+int main() {
+  InitializeNativeTarget();
+  InitializeNativeTargetAsmPrinter();
+  InitializeNativeTargetAsmParser();
+
+  // Install standard binary operators.
+  // 1 is lowest precedence.
+  BinopPrecedence['<'] = 10;
+  BinopPrecedence['+'] = 20;
+  BinopPrecedence['-'] = 20;
+  BinopPrecedence['*'] = 40; // highest.
+
+  // Prime the first token.
+  fprintf(stderr, "ready> ");
+  getNextToken();
+
+  TheJIT = std::make_unique<KaleidoscopeJIT>();
+
+  InitializeModuleAndPassManager();
+
+  // Run the main "interpreter loop" now.
+  MainLoop();
+
+  return 0;
+}
diff --git a/LLVM/cplusplus/toy6.cpp b/LLVM/cplusplus/toy6.cpp
new file mode 100644
index 0000000..ec08671
--- /dev/null
+++ b/LLVM/cplusplus/toy6.cpp
@@ -0,0 +1,1094 @@
+// Next Line modified for the FbI/h_da.de version (only)
+#include "KaleidoscopeJIT.h"
+#include "llvm/ADT/APFloat.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/LegacyPassManager.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Type.h"
+#include "llvm/IR/Verifier.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Transforms/InstCombine/InstCombine.h"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Scalar/GVN.h"
+#include <algorithm>
+#include <cassert>
+#include <cctype>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <map>
+#include <memory>
+#include <string>
+#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
+};
+
+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;
+    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)
+//===----------------------------------------------------------------------===//
+
+namespace {
+
+/// ExprAST - Base class for all expression nodes.
+class ExprAST {
+public:
+  virtual ~ExprAST() = default;
+
+  virtual Value *codegen() = 0;
+};
+
+/// NumberExprAST - Expression class for numeric literals like "1.0".
+class NumberExprAST : public ExprAST {
+  double Val;
+
+public:
+  NumberExprAST(double Val) : Val(Val) {}
+
+  Value *codegen() override;
+};
+
+/// VariableExprAST - Expression class for referencing a variable, like "a".
+class VariableExprAST : public ExprAST {
+  std::string Name;
+
+public:
+  VariableExprAST(const std::string &Name) : Name(Name) {}
+
+  Value *codegen() override;
+};
+
+/// UnaryExprAST - Expression class for a unary operator.
+class UnaryExprAST : public ExprAST {
+  char Opcode;
+  std::unique_ptr<ExprAST> Operand;
+
+public:
+  UnaryExprAST(char Opcode, std::unique_ptr<ExprAST> Operand)
+      : Opcode(Opcode), Operand(std::move(Operand)) {}
+
+  Value *codegen() override;
+};
+
+/// BinaryExprAST - Expression class for a binary operator.
+class BinaryExprAST : public ExprAST {
+  char Op;
+  std::unique_ptr<ExprAST> LHS, RHS;
+
+public:
+  BinaryExprAST(char Op, std::unique_ptr<ExprAST> LHS,
+                std::unique_ptr<ExprAST> RHS)
+      : Op(Op), LHS(std::move(LHS)), RHS(std::move(RHS)) {}
+
+  Value *codegen() override;
+};
+
+/// CallExprAST - Expression class for function calls.
+class CallExprAST : public ExprAST {
+  std::string Callee;
+  std::vector<std::unique_ptr<ExprAST>> Args;
+
+public:
+  CallExprAST(const std::string &Callee,
+              std::vector<std::unique_ptr<ExprAST>> Args)
+      : Callee(Callee), Args(std::move(Args)) {}
+
+  Value *codegen() override;
+};
+
+/// IfExprAST - Expression class for if/then/else.
+class IfExprAST : public ExprAST {
+  std::unique_ptr<ExprAST> Cond, Then, Else;
+
+public:
+  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 *codegen() override;
+};
+
+/// ForExprAST - Expression class for for/in.
+class ForExprAST : public ExprAST {
+  std::string VarName;
+  std::unique_ptr<ExprAST> Start, End, Step, Body;
+
+public:
+  ForExprAST(const std::string &VarName, std::unique_ptr<ExprAST> Start,
+             std::unique_ptr<ExprAST> End, std::unique_ptr<ExprAST> Step,
+             std::unique_ptr<ExprAST> Body)
+      : VarName(VarName), Start(std::move(Start)), End(std::move(End)),
+        Step(std::move(Step)), Body(std::move(Body)) {}
+
+  Value *codegen() override;
+};
+
+/// PrototypeAST - This class represents the "prototype" for a function,
+/// which captures its name, and its argument names (thus implicitly the number
+/// of arguments the function takes), as well as if it is an operator.
+class PrototypeAST {
+  std::string Name;
+  std::vector<std::string> Args;
+  bool IsOperator;
+  unsigned Precedence; // Precedence if a binary op.
+
+public:
+  PrototypeAST(const std::string &Name, std::vector<std::string> Args,
+               bool IsOperator = false, unsigned Prec = 0)
+      : Name(Name), Args(std::move(Args)), IsOperator(IsOperator),
+        Precedence(Prec) {}
+
+  Function *codegen();
+  const std::string &getName() const { return Name; }
+
+  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];
+  }
+
+  unsigned getBinaryPrecedence() const { return Precedence; }
+};
+
+/// FunctionAST - This class represents a function definition itself.
+class FunctionAST {
+  std::unique_ptr<PrototypeAST> Proto;
+  std::unique_ptr<ExprAST> Body;
+
+public:
+  FunctionAST(std::unique_ptr<PrototypeAST> Proto,
+              std::unique_ptr<ExprAST> Body)
+      : Proto(std::move(Proto)), Body(std::move(Body)) {}
+
+  Function *codegen();
+};
+
+} // end anonymous namespace
+
+//===----------------------------------------------------------------------===//
+// 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;
+}
+
+/// Error* - These are little helper functions for error handling.
+std::unique_ptr<ExprAST> LogError(const char *Str) {
+  fprintf(stderr, "Error: %s\n", Str);
+  return nullptr;
+}
+
+std::unique_ptr<PrototypeAST> LogErrorP(const char *Str) {
+  LogError(Str);
+  return nullptr;
+}
+
+static std::unique_ptr<ExprAST> ParseExpression();
+
+/// numberexpr ::= number
+static std::unique_ptr<ExprAST> ParseNumberExpr() {
+  auto Result = std::make_unique<NumberExprAST>(NumVal);
+  getNextToken(); // consume the number
+  return std::move(Result);
+}
+
+/// parenexpr ::= '(' expression ')'
+static std::unique_ptr<ExprAST> ParseParenExpr() {
+  getNextToken(); // eat (.
+  auto V = ParseExpression();
+  if (!V)
+    return nullptr;
+
+  if (CurTok != ')')
+    return LogError("expected ')'");
+  getNextToken(); // eat ).
+  return V;
+}
+
+/// identifierexpr
+///   ::= identifier
+///   ::= identifier '(' expression* ')'
+static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
+  std::string IdName = IdentifierStr;
+
+  getNextToken(); // eat identifier.
+
+  if (CurTok != '(') // Simple variable ref.
+    return std::make_unique<VariableExprAST>(IdName);
+
+  // Call.
+  getNextToken(); // eat (
+  std::vector<std::unique_ptr<ExprAST>> Args;
+  if (CurTok != ')') {
+    while (true) {
+      if (auto Arg = ParseExpression())
+        Args.push_back(std::move(Arg));
+      else
+        return nullptr;
+
+      if (CurTok == ')')
+        break;
+
+      if (CurTok != ',')
+        return LogError("Expected ')' or ',' in argument list");
+      getNextToken();
+    }
+  }
+
+  // Eat the ')'.
+  getNextToken();
+
+  return std::make_unique<CallExprAST>(IdName, std::move(Args));
+}
+
+/// 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 LogError("expected then");
+  getNextToken(); // eat the then
+
+  auto Then = ParseExpression();
+  if (!Then)
+    return nullptr;
+
+  if (CurTok != tok_else)
+    return LogError("expected else");
+
+  getNextToken();
+
+  auto Else = ParseExpression();
+  if (!Else)
+    return nullptr;
+
+  return std::make_unique<IfExprAST>(std::move(Cond), std::move(Then),
+                                      std::move(Else));
+}
+
+/// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression
+static std::unique_ptr<ExprAST> ParseForExpr() {
+  getNextToken(); // eat the for.
+
+  if (CurTok != tok_identifier)
+    return LogError("expected identifier after for");
+
+  std::string IdName = IdentifierStr;
+  getNextToken(); // eat identifier.
+
+  if (CurTok != '=')
+    return LogError("expected '=' after for");
+  getNextToken(); // eat '='.
+
+  auto Start = ParseExpression();
+  if (!Start)
+    return nullptr;
+  if (CurTok != ',')
+    return LogError("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 LogError("expected 'in' after for");
+  getNextToken(); // eat 'in'.
+
+  auto Body = ParseExpression();
+  if (!Body)
+    return nullptr;
+
+  return std::make_unique<ForExprAST>(IdName, std::move(Start), std::move(End),
+                                       std::move(Step), std::move(Body));
+}
+
+/// primary
+///   ::= identifierexpr
+///   ::= numberexpr
+///   ::= parenexpr
+///   ::= ifexpr
+///   ::= forexpr
+static std::unique_ptr<ExprAST> ParsePrimary() {
+  switch (CurTok) {
+  default:
+    return LogError("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();
+  }
+}
+
+/// 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 std::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 =
+        std::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 LogErrorP("Expected function name in prototype");
+  case tok_identifier:
+    FnName = IdentifierStr;
+    Kind = 0;
+    getNextToken();
+    break;
+  case tok_unary:
+    getNextToken();
+    if (!isascii(CurTok))
+      return LogErrorP("Expected unary operator");
+    FnName = "unary";
+    FnName += (char)CurTok;
+    Kind = 1;
+    getNextToken();
+    break;
+  case tok_binary:
+    getNextToken();
+    if (!isascii(CurTok))
+      return LogErrorP("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 LogErrorP("Invalid precedence: must be 1..100");
+      BinaryPrecedence = (unsigned)NumVal;
+      getNextToken();
+    }
+    break;
+  }
+
+  if (CurTok != '(')
+    return LogErrorP("Expected '(' in prototype");
+
+  std::vector<std::string> ArgNames;
+  while (getNextToken() == tok_identifier)
+    ArgNames.push_back(IdentifierStr);
+  if (CurTok != ')')
+    return LogErrorP("Expected ')' in prototype");
+
+  // success.
+  getNextToken(); // eat ')'.
+
+  // Verify right number of names for operator.
+  if (Kind && ArgNames.size() != Kind)
+    return LogErrorP("Invalid number of operands for operator");
+
+  return std::make_unique<PrototypeAST>(FnName, 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 E = ParseExpression())
+    return std::make_unique<FunctionAST>(std::move(Proto), std::move(E));
+  return nullptr;
+}
+
+/// toplevelexpr ::= expression
+static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
+  if (auto E = ParseExpression()) {
+    // Make an anonymous proto.
+    auto Proto = std::make_unique<PrototypeAST>("__anon_expr",
+                                                 std::vector<std::string>());
+    return std::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
+//===----------------------------------------------------------------------===//
+
+static LLVMContext TheContext;
+static IRBuilder<> Builder(TheContext);
+static std::unique_ptr<Module> TheModule;
+static std::map<std::string, Value *> NamedValues;
+static std::unique_ptr<legacy::FunctionPassManager> TheFPM;
+static std::unique_ptr<KaleidoscopeJIT> TheJIT;
+static std::map<std::string, std::unique_ptr<PrototypeAST>> FunctionProtos;
+
+Value *LogErrorV(const char *Str) {
+  LogError(Str);
+  return nullptr;
+}
+
+Function *getFunction(std::string Name) {
+  // First, see if the function has already been added to the current module.
+  if (auto *F = TheModule->getFunction(Name))
+    return F;
+
+  // If not, check whether we can codegen the declaration from some existing
+  // prototype.
+  auto FI = FunctionProtos.find(Name);
+  if (FI != FunctionProtos.end())
+    return FI->second->codegen();
+
+  // If no existing prototype exists, return null.
+  return nullptr;
+}
+
+Value *NumberExprAST::codegen() {
+  return ConstantFP::get(TheContext, APFloat(Val));
+}
+
+Value *VariableExprAST::codegen() {
+  // Look this variable up in the function.
+  Value *V = NamedValues[Name];
+  if (!V)
+    return LogErrorV("Unknown variable name");
+  return V;
+}
+
+Value *UnaryExprAST::codegen() {
+  Value *OperandV = Operand->codegen();
+  if (!OperandV)
+    return nullptr;
+
+  Function *F = getFunction(std::string("unary") + Opcode);
+  if (!F)
+    return LogErrorV("Unknown unary operator");
+
+  return Builder.CreateCall(F, OperandV, "unop");
+}
+
+Value *BinaryExprAST::codegen() {
+  Value *L = LHS->codegen();
+  Value *R = RHS->codegen();
+  if (!L || !R)
+    return nullptr;
+
+  switch (Op) {
+  case '+':
+    return Builder.CreateFAdd(L, R, "addtmp");
+  case '-':
+    return Builder.CreateFSub(L, R, "subtmp");
+  case '*':
+    return Builder.CreateFMul(L, R, "multmp");
+  case '<':
+    L = Builder.CreateFCmpULT(L, R, "cmptmp");
+    // Convert bool 0/1 to double 0.0 or 1.0
+    return Builder.CreateUIToFP(L, Type::getDoubleTy(TheContext), "booltmp");
+  default:
+    break;
+  }
+
+  // If it wasn't a builtin binary operator, it must be a user defined one. Emit
+  // a call to it.
+  Function *F = getFunction(std::string("binary") + Op);
+  assert(F && "binary operator not found!");
+
+  Value *Ops[] = {L, R};
+  return Builder.CreateCall(F, Ops, "binop");
+}
+
+Value *CallExprAST::codegen() {
+  // Look up the name in the global module table.
+  Function *CalleeF = getFunction(Callee);
+  if (!CalleeF)
+    return LogErrorV("Unknown function referenced");
+
+  // If argument mismatch error.
+  if (CalleeF->arg_size() != Args.size())
+    return LogErrorV("Incorrect # arguments passed");
+
+  std::vector<Value *> ArgsV;
+  for (unsigned i = 0, e = Args.size(); i != e; ++i) {
+    ArgsV.push_back(Args[i]->codegen());
+    if (!ArgsV.back())
+      return nullptr;
+  }
+
+  return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
+}
+
+Value *IfExprAST::codegen() {
+  Value *CondV = Cond->codegen();
+  if (!CondV)
+    return nullptr;
+
+  // Convert condition to a bool by comparing non-equal to 0.0.
+  CondV = Builder.CreateFCmpONE(
+      CondV, ConstantFP::get(TheContext, APFloat(0.0)), "ifcond");
+
+  Function *TheFunction = Builder.GetInsertBlock()->getParent();
+
+  // Create blocks for the then and else cases.  Insert the 'then' block at the
+  // end of the function.
+  BasicBlock *ThenBB = BasicBlock::Create(TheContext, "then", TheFunction);
+  BasicBlock *ElseBB = BasicBlock::Create(TheContext, "else");
+  BasicBlock *MergeBB = BasicBlock::Create(TheContext, "ifcont");
+
+  Builder.CreateCondBr(CondV, ThenBB, ElseBB);
+
+  // Emit then value.
+  Builder.SetInsertPoint(ThenBB);
+
+  Value *ThenV = Then->codegen();
+  if (!ThenV)
+    return nullptr;
+
+  Builder.CreateBr(MergeBB);
+  // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
+  ThenBB = Builder.GetInsertBlock();
+
+  // Emit else block.
+  TheFunction->getBasicBlockList().push_back(ElseBB);
+  Builder.SetInsertPoint(ElseBB);
+
+  Value *ElseV = Else->codegen();
+  if (!ElseV)
+    return nullptr;
+
+  Builder.CreateBr(MergeBB);
+  // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
+  ElseBB = Builder.GetInsertBlock();
+
+  // Emit merge block.
+  TheFunction->getBasicBlockList().push_back(MergeBB);
+  Builder.SetInsertPoint(MergeBB);
+  PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(TheContext), 2, "iftmp");
+
+  PN->addIncoming(ThenV, ThenBB);
+  PN->addIncoming(ElseV, ElseBB);
+  return PN;
+}
+
+// Output for-loop as:
+//   ...
+//   start = startexpr
+//   goto loop
+// loop:
+//   variable = phi [start, loopheader], [nextvariable, loopend]
+//   ...
+//   bodyexpr
+//   ...
+// loopend:
+//   step = stepexpr
+//   nextvariable = variable + step
+//   endcond = endexpr
+//   br endcond, loop, endloop
+// outloop:
+Value *ForExprAST::codegen() {
+  // Emit the start code first, without 'variable' in scope.
+  Value *StartVal = Start->codegen();
+  if (!StartVal)
+    return nullptr;
+
+  // Make the new basic block for the loop header, inserting after current
+  // block.
+  Function *TheFunction = Builder.GetInsertBlock()->getParent();
+  BasicBlock *PreheaderBB = Builder.GetInsertBlock();
+  BasicBlock *LoopBB = BasicBlock::Create(TheContext, "loop", TheFunction);
+
+  // Insert an explicit fall through from the current block to the LoopBB.
+  Builder.CreateBr(LoopBB);
+
+  // Start insertion in LoopBB.
+  Builder.SetInsertPoint(LoopBB);
+
+  // Start the PHI node with an entry for Start.
+  PHINode *Variable =
+      Builder.CreatePHI(Type::getDoubleTy(TheContext), 2, VarName);
+  Variable->addIncoming(StartVal, PreheaderBB);
+
+  // 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.
+  Value *OldVal = NamedValues[VarName];
+  NamedValues[VarName] = Variable;
+
+  // 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->codegen())
+    return nullptr;
+
+  // Emit the step value.
+  Value *StepVal = nullptr;
+  if (Step) {
+    StepVal = Step->codegen();
+    if (!StepVal)
+      return nullptr;
+  } else {
+    // If not specified, use 1.0.
+    StepVal = ConstantFP::get(TheContext, APFloat(1.0));
+  }
+
+  Value *NextVar = Builder.CreateFAdd(Variable, StepVal, "nextvar");
+
+  // Compute the end condition.
+  Value *EndCond = End->codegen();
+  if (!EndCond)
+    return nullptr;
+
+  // Convert condition to a bool by comparing non-equal to 0.0.
+  EndCond = Builder.CreateFCmpONE(
+      EndCond, ConstantFP::get(TheContext, APFloat(0.0)), "loopcond");
+
+  // Create the "after loop" block and insert it.
+  BasicBlock *LoopEndBB = Builder.GetInsertBlock();
+  BasicBlock *AfterBB =
+      BasicBlock::Create(TheContext, "afterloop", TheFunction);
+
+  // Insert the conditional branch into the end of LoopEndBB.
+  Builder.CreateCondBr(EndCond, LoopBB, AfterBB);
+
+  // Any new code will be inserted in AfterBB.
+  Builder.SetInsertPoint(AfterBB);
+
+  // Add a new entry to the PHI node for the backedge.
+  Variable->addIncoming(NextVar, LoopEndBB);
+
+  // Restore the unshadowed variable.
+  if (OldVal)
+    NamedValues[VarName] = OldVal;
+  else
+    NamedValues.erase(VarName);
+
+  // for expr always returns 0.0.
+  return Constant::getNullValue(Type::getDoubleTy(TheContext));
+}
+
+Function *PrototypeAST::codegen() {
+  // Make the function type:  double(double,double) etc.
+  std::vector<Type *> Doubles(Args.size(), Type::getDoubleTy(TheContext));
+  FunctionType *FT =
+      FunctionType::get(Type::getDoubleTy(TheContext), Doubles, false);
+
+  Function *F =
+      Function::Create(FT, Function::ExternalLinkage, Name, TheModule.get());
+
+  // Set names for all arguments.
+  unsigned Idx = 0;
+  for (auto &Arg : F->args())
+    Arg.setName(Args[Idx++]);
+
+  return F;
+}
+
+Function *FunctionAST::codegen() {
+  // Transfer ownership of the prototype to the FunctionProtos map, but keep a
+  // reference to it for use below.
+  auto &P = *Proto;
+  FunctionProtos[Proto->getName()] = std::move(Proto);
+  Function *TheFunction = getFunction(P.getName());
+  if (!TheFunction)
+    return nullptr;
+
+  // If this is an operator, install it.
+  if (P.isBinaryOp())
+    BinopPrecedence[P.getOperatorName()] = P.getBinaryPrecedence();
+
+  // Create a new basic block to start insertion into.
+  BasicBlock *BB = BasicBlock::Create(TheContext, "entry", TheFunction);
+  Builder.SetInsertPoint(BB);
+
+  // Record the function arguments in the NamedValues map.
+  NamedValues.clear();
+  for (auto &Arg : TheFunction->args())
+    NamedValues[std::string(Arg.getName())] = &Arg;
+
+  if (Value *RetVal = Body->codegen()) {
+    // Finish off the function.
+    Builder.CreateRet(RetVal);
+
+    // Validate the generated code, checking for consistency.
+    verifyFunction(*TheFunction);
+
+    // Run the optimizer on the function.
+    TheFPM->run(*TheFunction);
+
+    return TheFunction;
+  }
+
+  // Error reading body, remove function.
+  TheFunction->eraseFromParent();
+
+  if (P.isBinaryOp())
+    BinopPrecedence.erase(P.getOperatorName());
+  return nullptr;
+}
+
+//===----------------------------------------------------------------------===//
+// Top-Level parsing and JIT Driver
+//===----------------------------------------------------------------------===//
+
+static void InitializeModuleAndPassManager() {
+  // Open a new module.
+  TheModule = std::make_unique<Module>("my cool jit", TheContext);
+  TheModule->setDataLayout(TheJIT->getTargetMachine().createDataLayout());
+
+  // Create a new pass manager attached to it.
+  TheFPM = std::make_unique<legacy::FunctionPassManager>(TheModule.get());
+
+  // Do simple "peephole" optimizations and bit-twiddling optzns.
+  TheFPM->add(createInstructionCombiningPass());
+  // Reassociate expressions.
+  TheFPM->add(createReassociatePass());
+  // Eliminate Common SubExpressions.
+  TheFPM->add(createGVNPass());
+  // Simplify the control flow graph (deleting unreachable blocks, etc).
+  TheFPM->add(createCFGSimplificationPass());
+
+  TheFPM->doInitialization();
+}
+
+static void HandleDefinition() {
+  if (auto FnAST = ParseDefinition()) {
+    if (auto *FnIR = FnAST->codegen()) {
+      fprintf(stderr, "Read function definition:");
+      FnIR->print(errs());
+      fprintf(stderr, "\n");
+      TheJIT->addModule(std::move(TheModule));
+      InitializeModuleAndPassManager();
+    }
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+static void HandleExtern() {
+  if (auto ProtoAST = ParseExtern()) {
+    if (auto *FnIR = ProtoAST->codegen()) {
+      fprintf(stderr, "Read extern: ");
+      FnIR->print(errs());
+      fprintf(stderr, "\n");
+      FunctionProtos[ProtoAST->getName()] = std::move(ProtoAST);
+    }
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+static void HandleTopLevelExpression() {
+  // Evaluate a top-level expression into an anonymous function.
+  if (auto FnAST = ParseTopLevelExpr()) {
+    if (FnAST->codegen()) {
+      // JIT the module containing the anonymous expression, keeping a handle so
+      // we can free it later.
+      auto H = TheJIT->addModule(std::move(TheModule));
+      InitializeModuleAndPassManager();
+
+      // Search the JIT for the __anon_expr symbol.
+      auto ExprSymbol = TheJIT->findSymbol("__anon_expr");
+      assert(ExprSymbol && "Function not found");
+
+      // Get the symbol's address and 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)cantFail(ExprSymbol.getAddress());
+      fprintf(stderr, "Evaluated to %f\n", FP());
+
+      // Delete the anonymous expression module from the JIT.
+      TheJIT->removeModule(H);
+    }
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+/// top ::= definition | external | expression | ';'
+static void MainLoop() {
+  while (true) {
+    fprintf(stderr, "ready> ");
+    switch (CurTok) {
+    case tok_eof:
+      return;
+    case ';': // ignore top-level semicolons.
+      getNextToken();
+      break;
+    case tok_def:
+      HandleDefinition();
+      break;
+    case tok_extern:
+      HandleExtern();
+      break;
+    default:
+      HandleTopLevelExpression();
+      break;
+    }
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// "Library" functions that can be "extern'd" from user code.
+//===----------------------------------------------------------------------===//
+
+#ifdef _WIN32
+#define DLLEXPORT __declspec(dllexport)
+#else
+#define DLLEXPORT
+#endif
+
+/// putchard - putchar that takes a double and returns 0.
+extern "C" DLLEXPORT double putchard(double X) {
+  fputc((char)X, stderr);
+  return 0;
+}
+
+/// printd - printf that takes a double prints it as "%f\n", returning 0.
+extern "C" DLLEXPORT double printd(double X) {
+  fprintf(stderr, "%f\n", X);
+  return 0;
+}
+
+//===----------------------------------------------------------------------===//
+// Main driver code.
+//===----------------------------------------------------------------------===//
+
+int main() {
+  InitializeNativeTarget();
+  InitializeNativeTargetAsmPrinter();
+  InitializeNativeTargetAsmParser();
+
+  // Install standard binary operators.
+  // 1 is lowest precedence.
+  BinopPrecedence['<'] = 10;
+  BinopPrecedence['+'] = 20;
+  BinopPrecedence['-'] = 20;
+  BinopPrecedence['*'] = 40; // highest.
+
+  // Prime the first token.
+  fprintf(stderr, "ready> ");
+  getNextToken();
+
+  TheJIT = std::make_unique<KaleidoscopeJIT>();
+
+  InitializeModuleAndPassManager();
+
+  // Run the main "interpreter loop" now.
+  MainLoop();
+
+  return 0;
+}
diff --git a/LLVM/cplusplus/toy7.cpp b/LLVM/cplusplus/toy7.cpp
new file mode 100644
index 0000000..f6a3494
--- /dev/null
+++ b/LLVM/cplusplus/toy7.cpp
@@ -0,0 +1,1265 @@
+// Next Line modified for the FbI/h_da.de version (only)
+#include "KaleidoscopeJIT.h"
+#include "llvm/ADT/APFloat.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/LegacyPassManager.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Type.h"
+#include "llvm/IR/Verifier.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Transforms/InstCombine/InstCombine.h"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Scalar/GVN.h"
+#include "llvm/Transforms/Utils.h"
+#include <algorithm>
+#include <cassert>
+#include <cctype>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <map>
+#include <memory>
+#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)
+//===----------------------------------------------------------------------===//
+
+namespace {
+
+/// ExprAST - Base class for all expression nodes.
+class ExprAST {
+public:
+  virtual ~ExprAST() = default;
+
+  virtual Value *codegen() = 0;
+};
+
+/// NumberExprAST - Expression class for numeric literals like "1.0".
+class NumberExprAST : public ExprAST {
+  double Val;
+
+public:
+  NumberExprAST(double Val) : Val(Val) {}
+
+  Value *codegen() override;
+};
+
+/// VariableExprAST - Expression class for referencing a variable, like "a".
+class VariableExprAST : public ExprAST {
+  std::string Name;
+
+public:
+  VariableExprAST(const std::string &Name) : Name(Name) {}
+
+  Value *codegen() override;
+  const std::string &getName() const { return Name; }
+};
+
+/// UnaryExprAST - Expression class for a unary operator.
+class UnaryExprAST : public ExprAST {
+  char Opcode;
+  std::unique_ptr<ExprAST> Operand;
+
+public:
+  UnaryExprAST(char Opcode, std::unique_ptr<ExprAST> Operand)
+      : Opcode(Opcode), Operand(std::move(Operand)) {}
+
+  Value *codegen() override;
+};
+
+/// BinaryExprAST - Expression class for a binary operator.
+class BinaryExprAST : public ExprAST {
+  char Op;
+  std::unique_ptr<ExprAST> LHS, RHS;
+
+public:
+  BinaryExprAST(char Op, std::unique_ptr<ExprAST> LHS,
+                std::unique_ptr<ExprAST> RHS)
+      : Op(Op), LHS(std::move(LHS)), RHS(std::move(RHS)) {}
+
+  Value *codegen() override;
+};
+
+/// CallExprAST - Expression class for function calls.
+class CallExprAST : public ExprAST {
+  std::string Callee;
+  std::vector<std::unique_ptr<ExprAST>> Args;
+
+public:
+  CallExprAST(const std::string &Callee,
+              std::vector<std::unique_ptr<ExprAST>> Args)
+      : Callee(Callee), Args(std::move(Args)) {}
+
+  Value *codegen() override;
+};
+
+/// IfExprAST - Expression class for if/then/else.
+class IfExprAST : public ExprAST {
+  std::unique_ptr<ExprAST> Cond, Then, Else;
+
+public:
+  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 *codegen() override;
+};
+
+/// ForExprAST - Expression class for for/in.
+class ForExprAST : public ExprAST {
+  std::string VarName;
+  std::unique_ptr<ExprAST> Start, End, Step, Body;
+
+public:
+  ForExprAST(const std::string &VarName, std::unique_ptr<ExprAST> Start,
+             std::unique_ptr<ExprAST> End, std::unique_ptr<ExprAST> Step,
+             std::unique_ptr<ExprAST> Body)
+      : VarName(VarName), Start(std::move(Start)), End(std::move(End)),
+        Step(std::move(Step)), Body(std::move(Body)) {}
+
+  Value *codegen() override;
+};
+
+/// VarExprAST - Expression class for var/in
+class VarExprAST : public ExprAST {
+  std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames;
+  std::unique_ptr<ExprAST> Body;
+
+public:
+  VarExprAST(
+      std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames,
+      std::unique_ptr<ExprAST> Body)
+      : VarNames(std::move(VarNames)), Body(std::move(Body)) {}
+
+  Value *codegen() override;
+};
+
+/// PrototypeAST - This class represents the "prototype" for a function,
+/// which captures its name, and its argument names (thus implicitly the number
+/// of arguments the function takes), as well as if it is an operator.
+class PrototypeAST {
+  std::string Name;
+  std::vector<std::string> Args;
+  bool IsOperator;
+  unsigned Precedence; // Precedence if a binary op.
+
+public:
+  PrototypeAST(const std::string &Name, std::vector<std::string> Args,
+               bool IsOperator = false, unsigned Prec = 0)
+      : Name(Name), Args(std::move(Args)), IsOperator(IsOperator),
+        Precedence(Prec) {}
+
+  Function *codegen();
+  const std::string &getName() const { return Name; }
+
+  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];
+  }
+
+  unsigned getBinaryPrecedence() const { return Precedence; }
+};
+
+/// FunctionAST - This class represents a function definition itself.
+class FunctionAST {
+  std::unique_ptr<PrototypeAST> Proto;
+  std::unique_ptr<ExprAST> Body;
+
+public:
+  FunctionAST(std::unique_ptr<PrototypeAST> Proto,
+              std::unique_ptr<ExprAST> Body)
+      : Proto(std::move(Proto)), Body(std::move(Body)) {}
+
+  Function *codegen();
+};
+
+} // end anonymous namespace
+
+//===----------------------------------------------------------------------===//
+// 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;
+}
+
+/// LogError* - These are little helper functions for error handling.
+std::unique_ptr<ExprAST> LogError(const char *Str) {
+  fprintf(stderr, "Error: %s\n", Str);
+  return nullptr;
+}
+
+std::unique_ptr<PrototypeAST> LogErrorP(const char *Str) {
+  LogError(Str);
+  return nullptr;
+}
+
+static std::unique_ptr<ExprAST> ParseExpression();
+
+/// numberexpr ::= number
+static std::unique_ptr<ExprAST> ParseNumberExpr() {
+  auto Result = std::make_unique<NumberExprAST>(NumVal);
+  getNextToken(); // consume the number
+  return std::move(Result);
+}
+
+/// parenexpr ::= '(' expression ')'
+static std::unique_ptr<ExprAST> ParseParenExpr() {
+  getNextToken(); // eat (.
+  auto V = ParseExpression();
+  if (!V)
+    return nullptr;
+
+  if (CurTok != ')')
+    return LogError("expected ')'");
+  getNextToken(); // eat ).
+  return V;
+}
+
+/// identifierexpr
+///   ::= identifier
+///   ::= identifier '(' expression* ')'
+static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
+  std::string IdName = IdentifierStr;
+
+  getNextToken(); // eat identifier.
+
+  if (CurTok != '(') // Simple variable ref.
+    return std::make_unique<VariableExprAST>(IdName);
+
+  // Call.
+  getNextToken(); // eat (
+  std::vector<std::unique_ptr<ExprAST>> Args;
+  if (CurTok != ')') {
+    while (true) {
+      if (auto Arg = ParseExpression())
+        Args.push_back(std::move(Arg));
+      else
+        return nullptr;
+
+      if (CurTok == ')')
+        break;
+
+      if (CurTok != ',')
+        return LogError("Expected ')' or ',' in argument list");
+      getNextToken();
+    }
+  }
+
+  // Eat the ')'.
+  getNextToken();
+
+  return std::make_unique<CallExprAST>(IdName, std::move(Args));
+}
+
+/// 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 LogError("expected then");
+  getNextToken(); // eat the then
+
+  auto Then = ParseExpression();
+  if (!Then)
+    return nullptr;
+
+  if (CurTok != tok_else)
+    return LogError("expected else");
+
+  getNextToken();
+
+  auto Else = ParseExpression();
+  if (!Else)
+    return nullptr;
+
+  return std::make_unique<IfExprAST>(std::move(Cond), std::move(Then),
+                                      std::move(Else));
+}
+
+/// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression
+static std::unique_ptr<ExprAST> ParseForExpr() {
+  getNextToken(); // eat the for.
+
+  if (CurTok != tok_identifier)
+    return LogError("expected identifier after for");
+
+  std::string IdName = IdentifierStr;
+  getNextToken(); // eat identifier.
+
+  if (CurTok != '=')
+    return LogError("expected '=' after for");
+  getNextToken(); // eat '='.
+
+  auto Start = ParseExpression();
+  if (!Start)
+    return nullptr;
+  if (CurTok != ',')
+    return LogError("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 LogError("expected 'in' after for");
+  getNextToken(); // eat 'in'.
+
+  auto Body = ParseExpression();
+  if (!Body)
+    return nullptr;
+
+  return std::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<ExprAST> ParseVarExpr() {
+  getNextToken(); // eat the var.
+
+  std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames;
+
+  // At least one variable name is required.
+  if (CurTok != tok_identifier)
+    return LogError("expected identifier after var");
+
+  while (true) {
+    std::string Name = IdentifierStr;
+    getNextToken(); // eat identifier.
+
+    // Read the optional initializer.
+    std::unique_ptr<ExprAST> Init = nullptr;
+    if (CurTok == '=') {
+      getNextToken(); // eat the '='.
+
+      Init = ParseExpression();
+      if (!Init)
+        return nullptr;
+    }
+
+    VarNames.push_back(std::make_pair(Name, std::move(Init)));
+
+    // End of var list, exit loop.
+    if (CurTok != ',')
+      break;
+    getNextToken(); // eat the ','.
+
+    if (CurTok != tok_identifier)
+      return LogError("expected identifier list after var");
+  }
+
+  // At this point, we have to have 'in'.
+  if (CurTok != tok_in)
+    return LogError("expected 'in' keyword after 'var'");
+  getNextToken(); // eat 'in'.
+
+  auto Body = ParseExpression();
+  if (!Body)
+    return nullptr;
+
+  return std::make_unique<VarExprAST>(std::move(VarNames), std::move(Body));
+}
+
+/// primary
+///   ::= identifierexpr
+///   ::= numberexpr
+///   ::= parenexpr
+///   ::= ifexpr
+///   ::= forexpr
+///   ::= varexpr
+static std::unique_ptr<ExprAST> ParsePrimary() {
+  switch (CurTok) {
+  default:
+    return LogError("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 std::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 =
+        std::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 LogErrorP("Expected function name in prototype");
+  case tok_identifier:
+    FnName = IdentifierStr;
+    Kind = 0;
+    getNextToken();
+    break;
+  case tok_unary:
+    getNextToken();
+    if (!isascii(CurTok))
+      return LogErrorP("Expected unary operator");
+    FnName = "unary";
+    FnName += (char)CurTok;
+    Kind = 1;
+    getNextToken();
+    break;
+  case tok_binary:
+    getNextToken();
+    if (!isascii(CurTok))
+      return LogErrorP("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 LogErrorP("Invalid precedence: must be 1..100");
+      BinaryPrecedence = (unsigned)NumVal;
+      getNextToken();
+    }
+    break;
+  }
+
+  if (CurTok != '(')
+    return LogErrorP("Expected '(' in prototype");
+
+  std::vector<std::string> ArgNames;
+  while (getNextToken() == tok_identifier)
+    ArgNames.push_back(IdentifierStr);
+  if (CurTok != ')')
+    return LogErrorP("Expected ')' in prototype");
+
+  // success.
+  getNextToken(); // eat ')'.
+
+  // Verify right number of names for operator.
+  if (Kind && ArgNames.size() != Kind)
+    return LogErrorP("Invalid number of operands for operator");
+
+  return std::make_unique<PrototypeAST>(FnName, 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 E = ParseExpression())
+    return std::make_unique<FunctionAST>(std::move(Proto), std::move(E));
+  return nullptr;
+}
+
+/// toplevelexpr ::= expression
+static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
+  if (auto E = ParseExpression()) {
+    // Make an anonymous proto.
+    auto Proto = std::make_unique<PrototypeAST>("__anon_expr",
+                                                 std::vector<std::string>());
+    return std::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
+//===----------------------------------------------------------------------===//
+
+static LLVMContext TheContext;
+static IRBuilder<> Builder(TheContext);
+static std::unique_ptr<Module> TheModule;
+static std::map<std::string, AllocaInst *> NamedValues;
+static std::unique_ptr<legacy::FunctionPassManager> TheFPM;
+static std::unique_ptr<KaleidoscopeJIT> TheJIT;
+static std::map<std::string, std::unique_ptr<PrototypeAST>> FunctionProtos;
+
+Value *LogErrorV(const char *Str) {
+  LogError(Str);
+  return nullptr;
+}
+
+Function *getFunction(std::string Name) {
+  // First, see if the function has already been added to the current module.
+  if (auto *F = TheModule->getFunction(Name))
+    return F;
+
+  // If not, check whether we can codegen the declaration from some existing
+  // prototype.
+  auto FI = FunctionProtos.find(Name);
+  if (FI != FunctionProtos.end())
+    return FI->second->codegen();
+
+  // If no existing prototype exists, return null.
+  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,
+                                          StringRef VarName) {
+  IRBuilder<> TmpB(&TheFunction->getEntryBlock(),
+                   TheFunction->getEntryBlock().begin());
+  return TmpB.CreateAlloca(Type::getDoubleTy(TheContext), nullptr, VarName);
+}
+
+Value *NumberExprAST::codegen() {
+  return ConstantFP::get(TheContext, APFloat(Val));
+}
+
+Value *VariableExprAST::codegen() {
+  // Look this variable up in the function.
+  Value *V = NamedValues[Name];
+  if (!V)
+    return LogErrorV("Unknown variable name");
+
+  // Load the value.
+  return Builder.CreateLoad(V, Name.c_str());
+}
+
+Value *UnaryExprAST::codegen() {
+  Value *OperandV = Operand->codegen();
+  if (!OperandV)
+    return nullptr;
+
+  Function *F = getFunction(std::string("unary") + Opcode);
+  if (!F)
+    return LogErrorV("Unknown unary operator");
+
+  return Builder.CreateCall(F, OperandV, "unop");
+}
+
+Value *BinaryExprAST::codegen() {
+  // Special case '=' because we don't want to emit the LHS as an expression.
+  if (Op == '=') {
+    // Assignment requires the LHS to be an identifier.
+    // This assume we're building without RTTI because LLVM builds that way by
+    // default.  If you build LLVM with RTTI this can be changed to a
+    // dynamic_cast for automatic error checking.
+    VariableExprAST *LHSE = static_cast<VariableExprAST *>(LHS.get());
+    if (!LHSE)
+      return LogErrorV("destination of '=' must be a variable");
+    // Codegen the RHS.
+    Value *Val = RHS->codegen();
+    if (!Val)
+      return nullptr;
+
+    // Look up the name.
+    Value *Variable = NamedValues[LHSE->getName()];
+    if (!Variable)
+      return LogErrorV("Unknown variable name");
+
+    Builder.CreateStore(Val, Variable);
+    return Val;
+  }
+
+  Value *L = LHS->codegen();
+  Value *R = RHS->codegen();
+  if (!L || !R)
+    return nullptr;
+
+  switch (Op) {
+  case '+':
+    return Builder.CreateFAdd(L, R, "addtmp");
+  case '-':
+    return Builder.CreateFSub(L, R, "subtmp");
+  case '*':
+    return Builder.CreateFMul(L, R, "multmp");
+  case '<':
+    L = Builder.CreateFCmpULT(L, R, "cmptmp");
+    // Convert bool 0/1 to double 0.0 or 1.0
+    return Builder.CreateUIToFP(L, Type::getDoubleTy(TheContext), "booltmp");
+  default:
+    break;
+  }
+
+  // If it wasn't a builtin binary operator, it must be a user defined one. Emit
+  // a call to it.
+  Function *F = getFunction(std::string("binary") + Op);
+  assert(F && "binary operator not found!");
+
+  Value *Ops[] = {L, R};
+  return Builder.CreateCall(F, Ops, "binop");
+}
+
+Value *CallExprAST::codegen() {
+  // Look up the name in the global module table.
+  Function *CalleeF = getFunction(Callee);
+  if (!CalleeF)
+    return LogErrorV("Unknown function referenced");
+
+  // If argument mismatch error.
+  if (CalleeF->arg_size() != Args.size())
+    return LogErrorV("Incorrect # arguments passed");
+
+  std::vector<Value *> ArgsV;
+  for (unsigned i = 0, e = Args.size(); i != e; ++i) {
+    ArgsV.push_back(Args[i]->codegen());
+    if (!ArgsV.back())
+      return nullptr;
+  }
+
+  return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
+}
+
+Value *IfExprAST::codegen() {
+  Value *CondV = Cond->codegen();
+  if (!CondV)
+    return nullptr;
+
+  // Convert condition to a bool by comparing non-equal to 0.0.
+  CondV = Builder.CreateFCmpONE(
+      CondV, ConstantFP::get(TheContext, APFloat(0.0)), "ifcond");
+
+  Function *TheFunction = Builder.GetInsertBlock()->getParent();
+
+  // Create blocks for the then and else cases.  Insert the 'then' block at the
+  // end of the function.
+  BasicBlock *ThenBB = BasicBlock::Create(TheContext, "then", TheFunction);
+  BasicBlock *ElseBB = BasicBlock::Create(TheContext, "else");
+  BasicBlock *MergeBB = BasicBlock::Create(TheContext, "ifcont");
+
+  Builder.CreateCondBr(CondV, ThenBB, ElseBB);
+
+  // Emit then value.
+  Builder.SetInsertPoint(ThenBB);
+
+  Value *ThenV = Then->codegen();
+  if (!ThenV)
+    return nullptr;
+
+  Builder.CreateBr(MergeBB);
+  // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
+  ThenBB = Builder.GetInsertBlock();
+
+  // Emit else block.
+  TheFunction->getBasicBlockList().push_back(ElseBB);
+  Builder.SetInsertPoint(ElseBB);
+
+  Value *ElseV = Else->codegen();
+  if (!ElseV)
+    return nullptr;
+
+  Builder.CreateBr(MergeBB);
+  // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
+  ElseBB = Builder.GetInsertBlock();
+
+  // Emit merge block.
+  TheFunction->getBasicBlockList().push_back(MergeBB);
+  Builder.SetInsertPoint(MergeBB);
+  PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(TheContext), 2, "iftmp");
+
+  PN->addIncoming(ThenV, ThenBB);
+  PN->addIncoming(ElseV, ElseBB);
+  return PN;
+}
+
+// Output for-loop 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:
+Value *ForExprAST::codegen() {
+  Function *TheFunction = Builder.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->codegen();
+  if (!StartVal)
+    return nullptr;
+
+  // Store the value into the alloca.
+  Builder.CreateStore(StartVal, Alloca);
+
+  // Make the new basic block for the loop header, inserting after current
+  // block.
+  BasicBlock *LoopBB = BasicBlock::Create(TheContext, "loop", TheFunction);
+
+  // Insert an explicit fall through from the current block to the LoopBB.
+  Builder.CreateBr(LoopBB);
+
+  // Start insertion in LoopBB.
+  Builder.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 = NamedValues[VarName];
+  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->codegen())
+    return nullptr;
+
+  // Emit the step value.
+  Value *StepVal = nullptr;
+  if (Step) {
+    StepVal = Step->codegen();
+    if (!StepVal)
+      return nullptr;
+  } else {
+    // If not specified, use 1.0.
+    StepVal = ConstantFP::get(TheContext, APFloat(1.0));
+  }
+
+  // Compute the end condition.
+  Value *EndCond = End->codegen();
+  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 = Builder.CreateLoad(Alloca, VarName.c_str());
+  Value *NextVar = Builder.CreateFAdd(CurVar, StepVal, "nextvar");
+  Builder.CreateStore(NextVar, Alloca);
+
+  // Convert condition to a bool by comparing non-equal to 0.0.
+  EndCond = Builder.CreateFCmpONE(
+      EndCond, ConstantFP::get(TheContext, APFloat(0.0)), "loopcond");
+
+  // Create the "after loop" block and insert it.
+  BasicBlock *AfterBB =
+      BasicBlock::Create(TheContext, "afterloop", TheFunction);
+
+  // Insert the conditional branch into the end of LoopEndBB.
+  Builder.CreateCondBr(EndCond, LoopBB, AfterBB);
+
+  // Any new code will be inserted in AfterBB.
+  Builder.SetInsertPoint(AfterBB);
+
+  // Restore the unshadowed variable.
+  if (OldVal)
+    NamedValues[VarName] = OldVal;
+  else
+    NamedValues.erase(VarName);
+
+  // for expr always returns 0.0.
+  return Constant::getNullValue(Type::getDoubleTy(TheContext));
+}
+
+Value *VarExprAST::codegen() {
+  std::vector<AllocaInst *> OldBindings;
+
+  Function *TheFunction = Builder.GetInsertBlock()->getParent();
+
+  // Register all variables and emit their initializer.
+  for (unsigned i = 0, e = VarNames.size(); i != e; ++i) {
+    const std::string &VarName = VarNames[i].first;
+    ExprAST *Init = VarNames[i].second.get();
+
+    // 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->codegen();
+      if (!InitVal)
+        return nullptr;
+    } else { // If not specified, use 0.0.
+      InitVal = ConstantFP::get(TheContext, APFloat(0.0));
+    }
+
+    AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
+    Builder.CreateStore(InitVal, Alloca);
+
+    // Remember the old variable binding so that we can restore the binding when
+    // we unrecurse.
+    OldBindings.push_back(NamedValues[VarName]);
+
+    // Remember this binding.
+    NamedValues[VarName] = Alloca;
+  }
+
+  // Codegen the body, now that all vars are in scope.
+  Value *BodyVal = Body->codegen();
+  if (!BodyVal)
+    return nullptr;
+
+  // Pop all our variables from scope.
+  for (unsigned i = 0, e = VarNames.size(); i != e; ++i)
+    NamedValues[VarNames[i].first] = OldBindings[i];
+
+  // Return the body computation.
+  return BodyVal;
+}
+
+Function *PrototypeAST::codegen() {
+  // Make the function type:  double(double,double) etc.
+  std::vector<Type *> Doubles(Args.size(), Type::getDoubleTy(TheContext));
+  FunctionType *FT =
+      FunctionType::get(Type::getDoubleTy(TheContext), Doubles, false);
+
+  Function *F =
+      Function::Create(FT, Function::ExternalLinkage, Name, TheModule.get());
+
+  // Set names for all arguments.
+  unsigned Idx = 0;
+  for (auto &Arg : F->args())
+    Arg.setName(Args[Idx++]);
+
+  return F;
+}
+
+Function *FunctionAST::codegen() {
+  // Transfer ownership of the prototype to the FunctionProtos map, but keep a
+  // reference to it for use below.
+  auto &P = *Proto;
+  FunctionProtos[Proto->getName()] = std::move(Proto);
+  Function *TheFunction = getFunction(P.getName());
+  if (!TheFunction)
+    return nullptr;
+
+  // If this is an operator, install it.
+  if (P.isBinaryOp())
+    BinopPrecedence[P.getOperatorName()] = P.getBinaryPrecedence();
+
+  // Create a new basic block to start insertion into.
+  BasicBlock *BB = BasicBlock::Create(TheContext, "entry", TheFunction);
+  Builder.SetInsertPoint(BB);
+
+  // Record the function arguments in the NamedValues map.
+  NamedValues.clear();
+  for (auto &Arg : TheFunction->args()) {
+    // Create an alloca for this variable.
+    AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, Arg.getName());
+
+    // Store the initial value into the alloca.
+    Builder.CreateStore(&Arg, Alloca);
+
+    // Add arguments to variable symbol table.
+    NamedValues[std::string(Arg.getName())] = Alloca;
+  }
+
+  if (Value *RetVal = Body->codegen()) {
+    // Finish off the function.
+    Builder.CreateRet(RetVal);
+
+    // Validate the generated code, checking for consistency.
+    verifyFunction(*TheFunction);
+
+    // Run the optimizer on the function.
+    TheFPM->run(*TheFunction);
+
+    return TheFunction;
+  }
+
+  // Error reading body, remove function.
+  TheFunction->eraseFromParent();
+
+  if (P.isBinaryOp())
+    BinopPrecedence.erase(P.getOperatorName());
+  return nullptr;
+}
+
+//===----------------------------------------------------------------------===//
+// Top-Level parsing and JIT Driver
+//===----------------------------------------------------------------------===//
+
+static void InitializeModuleAndPassManager() {
+  // Open a new module.
+  TheModule = std::make_unique<Module>("my cool jit", TheContext);
+  TheModule->setDataLayout(TheJIT->getTargetMachine().createDataLayout());
+
+  // Create a new pass manager attached to it.
+  TheFPM = std::make_unique<legacy::FunctionPassManager>(TheModule.get());
+
+  // Promote allocas to registers.
+  TheFPM->add(createPromoteMemoryToRegisterPass());
+  // Do simple "peephole" optimizations and bit-twiddling optzns.
+  TheFPM->add(createInstructionCombiningPass());
+  // Reassociate expressions.
+  TheFPM->add(createReassociatePass());
+  // Eliminate Common SubExpressions.
+  TheFPM->add(createGVNPass());
+  // Simplify the control flow graph (deleting unreachable blocks, etc).
+  TheFPM->add(createCFGSimplificationPass());
+
+  TheFPM->doInitialization();
+}
+
+static void HandleDefinition() {
+  if (auto FnAST = ParseDefinition()) {
+    if (auto *FnIR = FnAST->codegen()) {
+      fprintf(stderr, "Read function definition:");
+      FnIR->print(errs());
+      fprintf(stderr, "\n");
+      TheJIT->addModule(std::move(TheModule));
+      InitializeModuleAndPassManager();
+    }
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+static void HandleExtern() {
+  if (auto ProtoAST = ParseExtern()) {
+    if (auto *FnIR = ProtoAST->codegen()) {
+      fprintf(stderr, "Read extern: ");
+      FnIR->print(errs());
+      fprintf(stderr, "\n");
+      FunctionProtos[ProtoAST->getName()] = std::move(ProtoAST);
+    }
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+static void HandleTopLevelExpression() {
+  // Evaluate a top-level expression into an anonymous function.
+  if (auto FnAST = ParseTopLevelExpr()) {
+    if (FnAST->codegen()) {
+      // JIT the module containing the anonymous expression, keeping a handle so
+      // we can free it later.
+      auto H = TheJIT->addModule(std::move(TheModule));
+      InitializeModuleAndPassManager();
+
+      // Search the JIT for the __anon_expr symbol.
+      auto ExprSymbol = TheJIT->findSymbol("__anon_expr");
+      assert(ExprSymbol && "Function not found");
+
+      // Get the symbol's address and 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)cantFail(ExprSymbol.getAddress());
+      fprintf(stderr, "Evaluated to %f\n", FP());
+
+      // Delete the anonymous expression module from the JIT.
+      TheJIT->removeModule(H);
+    }
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+/// top ::= definition | external | expression | ';'
+static void MainLoop() {
+  while (true) {
+    fprintf(stderr, "ready> ");
+    switch (CurTok) {
+    case tok_eof:
+      return;
+    case ';': // ignore top-level semicolons.
+      getNextToken();
+      break;
+    case tok_def:
+      HandleDefinition();
+      break;
+    case tok_extern:
+      HandleExtern();
+      break;
+    default:
+      HandleTopLevelExpression();
+      break;
+    }
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// "Library" functions that can be "extern'd" from user code.
+//===----------------------------------------------------------------------===//
+
+#ifdef _WIN32
+#define DLLEXPORT __declspec(dllexport)
+#else
+#define DLLEXPORT
+#endif
+
+/// putchard - putchar that takes a double and returns 0.
+extern "C" DLLEXPORT double putchard(double X) {
+  fputc((char)X, stderr);
+  return 0;
+}
+
+/// printd - printf that takes a double prints it as "%f\n", returning 0.
+extern "C" DLLEXPORT double printd(double X) {
+  fprintf(stderr, "%f\n", X);
+  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; // highest.
+
+  // Prime the first token.
+  fprintf(stderr, "ready> ");
+  getNextToken();
+
+  TheJIT = std::make_unique<KaleidoscopeJIT>();
+
+  InitializeModuleAndPassManager();
+
+  // Run the main "interpreter loop" now.
+  MainLoop();
+
+  return 0;
+}
diff --git a/LLVM/cplusplus/toy8.cpp b/LLVM/cplusplus/toy8.cpp
new file mode 100644
index 0000000..b11cea4
--- /dev/null
+++ b/LLVM/cplusplus/toy8.cpp
@@ -0,0 +1,1270 @@
+#include "llvm/ADT/APFloat.h"
+#include "llvm/ADT/Optional.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/IR/BasicBlock.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/LegacyPassManager.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Type.h"
+#include "llvm/IR/Verifier.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Host.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetOptions.h"
+#include <algorithm>
+#include <cassert>
+#include <cctype>
+#include <cstdio>
+#include <cstdlib>
+#include <map>
+#include <memory>
+#include <string>
+#include <system_error>
+#include <utility>
+#include <vector>
+
+using namespace llvm;
+using namespace llvm::sys;
+
+//===----------------------------------------------------------------------===//
+// 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)
+//===----------------------------------------------------------------------===//
+
+namespace {
+
+/// ExprAST - Base class for all expression nodes.
+class ExprAST {
+public:
+  virtual ~ExprAST() = default;
+
+  virtual Value *codegen() = 0;
+};
+
+/// NumberExprAST - Expression class for numeric literals like "1.0".
+class NumberExprAST : public ExprAST {
+  double Val;
+
+public:
+  NumberExprAST(double Val) : Val(Val) {}
+
+  Value *codegen() override;
+};
+
+/// VariableExprAST - Expression class for referencing a variable, like "a".
+class VariableExprAST : public ExprAST {
+  std::string Name;
+
+public:
+  VariableExprAST(const std::string &Name) : Name(Name) {}
+
+  Value *codegen() override;
+  const std::string &getName() const { return Name; }
+};
+
+/// UnaryExprAST - Expression class for a unary operator.
+class UnaryExprAST : public ExprAST {
+  char Opcode;
+  std::unique_ptr<ExprAST> Operand;
+
+public:
+  UnaryExprAST(char Opcode, std::unique_ptr<ExprAST> Operand)
+      : Opcode(Opcode), Operand(std::move(Operand)) {}
+
+  Value *codegen() override;
+};
+
+/// BinaryExprAST - Expression class for a binary operator.
+class BinaryExprAST : public ExprAST {
+  char Op;
+  std::unique_ptr<ExprAST> LHS, RHS;
+
+public:
+  BinaryExprAST(char Op, std::unique_ptr<ExprAST> LHS,
+                std::unique_ptr<ExprAST> RHS)
+      : Op(Op), LHS(std::move(LHS)), RHS(std::move(RHS)) {}
+
+  Value *codegen() override;
+};
+
+/// CallExprAST - Expression class for function calls.
+class CallExprAST : public ExprAST {
+  std::string Callee;
+  std::vector<std::unique_ptr<ExprAST>> Args;
+
+public:
+  CallExprAST(const std::string &Callee,
+              std::vector<std::unique_ptr<ExprAST>> Args)
+      : Callee(Callee), Args(std::move(Args)) {}
+
+  Value *codegen() override;
+};
+
+/// IfExprAST - Expression class for if/then/else.
+class IfExprAST : public ExprAST {
+  std::unique_ptr<ExprAST> Cond, Then, Else;
+
+public:
+  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 *codegen() override;
+};
+
+/// ForExprAST - Expression class for for/in.
+class ForExprAST : public ExprAST {
+  std::string VarName;
+  std::unique_ptr<ExprAST> Start, End, Step, Body;
+
+public:
+  ForExprAST(const std::string &VarName, std::unique_ptr<ExprAST> Start,
+             std::unique_ptr<ExprAST> End, std::unique_ptr<ExprAST> Step,
+             std::unique_ptr<ExprAST> Body)
+      : VarName(VarName), Start(std::move(Start)), End(std::move(End)),
+        Step(std::move(Step)), Body(std::move(Body)) {}
+
+  Value *codegen() override;
+};
+
+/// VarExprAST - Expression class for var/in
+class VarExprAST : public ExprAST {
+  std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames;
+  std::unique_ptr<ExprAST> Body;
+
+public:
+  VarExprAST(
+      std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames,
+      std::unique_ptr<ExprAST> Body)
+      : VarNames(std::move(VarNames)), Body(std::move(Body)) {}
+
+  Value *codegen() override;
+};
+
+/// PrototypeAST - This class represents the "prototype" for a function,
+/// which captures its name, and its argument names (thus implicitly the number
+/// of arguments the function takes), as well as if it is an operator.
+class PrototypeAST {
+  std::string Name;
+  std::vector<std::string> Args;
+  bool IsOperator;
+  unsigned Precedence; // Precedence if a binary op.
+
+public:
+  PrototypeAST(const std::string &Name, std::vector<std::string> Args,
+               bool IsOperator = false, unsigned Prec = 0)
+      : Name(Name), Args(std::move(Args)), IsOperator(IsOperator),
+        Precedence(Prec) {}
+
+  Function *codegen();
+  const std::string &getName() const { return Name; }
+
+  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];
+  }
+
+  unsigned getBinaryPrecedence() const { return Precedence; }
+};
+
+/// FunctionAST - This class represents a function definition itself.
+class FunctionAST {
+  std::unique_ptr<PrototypeAST> Proto;
+  std::unique_ptr<ExprAST> Body;
+
+public:
+  FunctionAST(std::unique_ptr<PrototypeAST> Proto,
+              std::unique_ptr<ExprAST> Body)
+      : Proto(std::move(Proto)), Body(std::move(Body)) {}
+
+  Function *codegen();
+};
+
+} // end anonymous namespace
+
+//===----------------------------------------------------------------------===//
+// 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;
+}
+
+/// LogError* - These are little helper functions for error handling.
+std::unique_ptr<ExprAST> LogError(const char *Str) {
+  fprintf(stderr, "Error: %s\n", Str);
+  return nullptr;
+}
+
+std::unique_ptr<PrototypeAST> LogErrorP(const char *Str) {
+  LogError(Str);
+  return nullptr;
+}
+
+static std::unique_ptr<ExprAST> ParseExpression();
+
+/// numberexpr ::= number
+static std::unique_ptr<ExprAST> ParseNumberExpr() {
+  auto Result = std::make_unique<NumberExprAST>(NumVal);
+  getNextToken(); // consume the number
+  return std::move(Result);
+}
+
+/// parenexpr ::= '(' expression ')'
+static std::unique_ptr<ExprAST> ParseParenExpr() {
+  getNextToken(); // eat (.
+  auto V = ParseExpression();
+  if (!V)
+    return nullptr;
+
+  if (CurTok != ')')
+    return LogError("expected ')'");
+  getNextToken(); // eat ).
+  return V;
+}
+
+/// identifierexpr
+///   ::= identifier
+///   ::= identifier '(' expression* ')'
+static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
+  std::string IdName = IdentifierStr;
+
+  getNextToken(); // eat identifier.
+
+  if (CurTok != '(') // Simple variable ref.
+    return std::make_unique<VariableExprAST>(IdName);
+
+  // Call.
+  getNextToken(); // eat (
+  std::vector<std::unique_ptr<ExprAST>> Args;
+  if (CurTok != ')') {
+    while (true) {
+      if (auto Arg = ParseExpression())
+        Args.push_back(std::move(Arg));
+      else
+        return nullptr;
+
+      if (CurTok == ')')
+        break;
+
+      if (CurTok != ',')
+        return LogError("Expected ')' or ',' in argument list");
+      getNextToken();
+    }
+  }
+
+  // Eat the ')'.
+  getNextToken();
+
+  return std::make_unique<CallExprAST>(IdName, std::move(Args));
+}
+
+/// 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 LogError("expected then");
+  getNextToken(); // eat the then
+
+  auto Then = ParseExpression();
+  if (!Then)
+    return nullptr;
+
+  if (CurTok != tok_else)
+    return LogError("expected else");
+
+  getNextToken();
+
+  auto Else = ParseExpression();
+  if (!Else)
+    return nullptr;
+
+  return std::make_unique<IfExprAST>(std::move(Cond), std::move(Then),
+                                      std::move(Else));
+}
+
+/// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression
+static std::unique_ptr<ExprAST> ParseForExpr() {
+  getNextToken(); // eat the for.
+
+  if (CurTok != tok_identifier)
+    return LogError("expected identifier after for");
+
+  std::string IdName = IdentifierStr;
+  getNextToken(); // eat identifier.
+
+  if (CurTok != '=')
+    return LogError("expected '=' after for");
+  getNextToken(); // eat '='.
+
+  auto Start = ParseExpression();
+  if (!Start)
+    return nullptr;
+  if (CurTok != ',')
+    return LogError("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 LogError("expected 'in' after for");
+  getNextToken(); // eat 'in'.
+
+  auto Body = ParseExpression();
+  if (!Body)
+    return nullptr;
+
+  return std::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<ExprAST> ParseVarExpr() {
+  getNextToken(); // eat the var.
+
+  std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames;
+
+  // At least one variable name is required.
+  if (CurTok != tok_identifier)
+    return LogError("expected identifier after var");
+
+  while (true) {
+    std::string Name = IdentifierStr;
+    getNextToken(); // eat identifier.
+
+    // Read the optional initializer.
+    std::unique_ptr<ExprAST> Init = nullptr;
+    if (CurTok == '=') {
+      getNextToken(); // eat the '='.
+
+      Init = ParseExpression();
+      if (!Init)
+        return nullptr;
+    }
+
+    VarNames.push_back(std::make_pair(Name, std::move(Init)));
+
+    // End of var list, exit loop.
+    if (CurTok != ',')
+      break;
+    getNextToken(); // eat the ','.
+
+    if (CurTok != tok_identifier)
+      return LogError("expected identifier list after var");
+  }
+
+  // At this point, we have to have 'in'.
+  if (CurTok != tok_in)
+    return LogError("expected 'in' keyword after 'var'");
+  getNextToken(); // eat 'in'.
+
+  auto Body = ParseExpression();
+  if (!Body)
+    return nullptr;
+
+  return std::make_unique<VarExprAST>(std::move(VarNames), std::move(Body));
+}
+
+/// primary
+///   ::= identifierexpr
+///   ::= numberexpr
+///   ::= parenexpr
+///   ::= ifexpr
+///   ::= forexpr
+///   ::= varexpr
+static std::unique_ptr<ExprAST> ParsePrimary() {
+  switch (CurTok) {
+  default:
+    return LogError("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 std::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 =
+        std::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 LogErrorP("Expected function name in prototype");
+  case tok_identifier:
+    FnName = IdentifierStr;
+    Kind = 0;
+    getNextToken();
+    break;
+  case tok_unary:
+    getNextToken();
+    if (!isascii(CurTok))
+      return LogErrorP("Expected unary operator");
+    FnName = "unary";
+    FnName += (char)CurTok;
+    Kind = 1;
+    getNextToken();
+    break;
+  case tok_binary:
+    getNextToken();
+    if (!isascii(CurTok))
+      return LogErrorP("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 LogErrorP("Invalid precedence: must be 1..100");
+      BinaryPrecedence = (unsigned)NumVal;
+      getNextToken();
+    }
+    break;
+  }
+
+  if (CurTok != '(')
+    return LogErrorP("Expected '(' in prototype");
+
+  std::vector<std::string> ArgNames;
+  while (getNextToken() == tok_identifier)
+    ArgNames.push_back(IdentifierStr);
+  if (CurTok != ')')
+    return LogErrorP("Expected ')' in prototype");
+
+  // success.
+  getNextToken(); // eat ')'.
+
+  // Verify right number of names for operator.
+  if (Kind && ArgNames.size() != Kind)
+    return LogErrorP("Invalid number of operands for operator");
+
+  return std::make_unique<PrototypeAST>(FnName, 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 E = ParseExpression())
+    return std::make_unique<FunctionAST>(std::move(Proto), std::move(E));
+  return nullptr;
+}
+
+/// toplevelexpr ::= expression
+static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
+  if (auto E = ParseExpression()) {
+    // Make an anonymous proto.
+    auto Proto = std::make_unique<PrototypeAST>("__anon_expr",
+                                                 std::vector<std::string>());
+    return std::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
+//===----------------------------------------------------------------------===//
+
+static LLVMContext TheContext;
+static IRBuilder<> Builder(TheContext);
+static std::unique_ptr<Module> TheModule;
+static std::map<std::string, AllocaInst *> NamedValues;
+static std::map<std::string, std::unique_ptr<PrototypeAST>> FunctionProtos;
+
+Value *LogErrorV(const char *Str) {
+  LogError(Str);
+  return nullptr;
+}
+
+Function *getFunction(std::string Name) {
+  // First, see if the function has already been added to the current module.
+  if (auto *F = TheModule->getFunction(Name))
+    return F;
+
+  // If not, check whether we can codegen the declaration from some existing
+  // prototype.
+  auto FI = FunctionProtos.find(Name);
+  if (FI != FunctionProtos.end())
+    return FI->second->codegen();
+
+  // If no existing prototype exists, return null.
+  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,
+                                          StringRef VarName) {
+  IRBuilder<> TmpB(&TheFunction->getEntryBlock(),
+                   TheFunction->getEntryBlock().begin());
+  return TmpB.CreateAlloca(Type::getDoubleTy(TheContext), nullptr, VarName);
+}
+
+Value *NumberExprAST::codegen() {
+  return ConstantFP::get(TheContext, APFloat(Val));
+}
+
+Value *VariableExprAST::codegen() {
+  // Look this variable up in the function.
+  Value *V = NamedValues[Name];
+  if (!V)
+    return LogErrorV("Unknown variable name");
+
+  // Load the value.
+  return Builder.CreateLoad(V, Name.c_str());
+}
+
+Value *UnaryExprAST::codegen() {
+  Value *OperandV = Operand->codegen();
+  if (!OperandV)
+    return nullptr;
+
+  Function *F = getFunction(std::string("unary") + Opcode);
+  if (!F)
+    return LogErrorV("Unknown unary operator");
+
+  return Builder.CreateCall(F, OperandV, "unop");
+}
+
+Value *BinaryExprAST::codegen() {
+  // Special case '=' because we don't want to emit the LHS as an expression.
+  if (Op == '=') {
+    // Assignment requires the LHS to be an identifier.
+    // This assume we're building without RTTI because LLVM builds that way by
+    // default.  If you build LLVM with RTTI this can be changed to a
+    // dynamic_cast for automatic error checking.
+    VariableExprAST *LHSE = static_cast<VariableExprAST *>(LHS.get());
+    if (!LHSE)
+      return LogErrorV("destination of '=' must be a variable");
+    // Codegen the RHS.
+    Value *Val = RHS->codegen();
+    if (!Val)
+      return nullptr;
+
+    // Look up the name.
+    Value *Variable = NamedValues[LHSE->getName()];
+    if (!Variable)
+      return LogErrorV("Unknown variable name");
+
+    Builder.CreateStore(Val, Variable);
+    return Val;
+  }
+
+  Value *L = LHS->codegen();
+  Value *R = RHS->codegen();
+  if (!L || !R)
+    return nullptr;
+
+  switch (Op) {
+  case '+':
+    return Builder.CreateFAdd(L, R, "addtmp");
+  case '-':
+    return Builder.CreateFSub(L, R, "subtmp");
+  case '*':
+    return Builder.CreateFMul(L, R, "multmp");
+  case '<':
+    L = Builder.CreateFCmpULT(L, R, "cmptmp");
+    // Convert bool 0/1 to double 0.0 or 1.0
+    return Builder.CreateUIToFP(L, Type::getDoubleTy(TheContext), "booltmp");
+  default:
+    break;
+  }
+
+  // If it wasn't a builtin binary operator, it must be a user defined one. Emit
+  // a call to it.
+  Function *F = getFunction(std::string("binary") + Op);
+  assert(F && "binary operator not found!");
+
+  Value *Ops[] = {L, R};
+  return Builder.CreateCall(F, Ops, "binop");
+}
+
+Value *CallExprAST::codegen() {
+  // Look up the name in the global module table.
+  Function *CalleeF = getFunction(Callee);
+  if (!CalleeF)
+    return LogErrorV("Unknown function referenced");
+
+  // If argument mismatch error.
+  if (CalleeF->arg_size() != Args.size())
+    return LogErrorV("Incorrect # arguments passed");
+
+  std::vector<Value *> ArgsV;
+  for (unsigned i = 0, e = Args.size(); i != e; ++i) {
+    ArgsV.push_back(Args[i]->codegen());
+    if (!ArgsV.back())
+      return nullptr;
+  }
+
+  return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
+}
+
+Value *IfExprAST::codegen() {
+  Value *CondV = Cond->codegen();
+  if (!CondV)
+    return nullptr;
+
+  // Convert condition to a bool by comparing non-equal to 0.0.
+  CondV = Builder.CreateFCmpONE(
+      CondV, ConstantFP::get(TheContext, APFloat(0.0)), "ifcond");
+
+  Function *TheFunction = Builder.GetInsertBlock()->getParent();
+
+  // Create blocks for the then and else cases.  Insert the 'then' block at the
+  // end of the function.
+  BasicBlock *ThenBB = BasicBlock::Create(TheContext, "then", TheFunction);
+  BasicBlock *ElseBB = BasicBlock::Create(TheContext, "else");
+  BasicBlock *MergeBB = BasicBlock::Create(TheContext, "ifcont");
+
+  Builder.CreateCondBr(CondV, ThenBB, ElseBB);
+
+  // Emit then value.
+  Builder.SetInsertPoint(ThenBB);
+
+  Value *ThenV = Then->codegen();
+  if (!ThenV)
+    return nullptr;
+
+  Builder.CreateBr(MergeBB);
+  // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
+  ThenBB = Builder.GetInsertBlock();
+
+  // Emit else block.
+  TheFunction->getBasicBlockList().push_back(ElseBB);
+  Builder.SetInsertPoint(ElseBB);
+
+  Value *ElseV = Else->codegen();
+  if (!ElseV)
+    return nullptr;
+
+  Builder.CreateBr(MergeBB);
+  // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
+  ElseBB = Builder.GetInsertBlock();
+
+  // Emit merge block.
+  TheFunction->getBasicBlockList().push_back(MergeBB);
+  Builder.SetInsertPoint(MergeBB);
+  PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(TheContext), 2, "iftmp");
+
+  PN->addIncoming(ThenV, ThenBB);
+  PN->addIncoming(ElseV, ElseBB);
+  return PN;
+}
+
+// Output for-loop 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:
+Value *ForExprAST::codegen() {
+  Function *TheFunction = Builder.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->codegen();
+  if (!StartVal)
+    return nullptr;
+
+  // Store the value into the alloca.
+  Builder.CreateStore(StartVal, Alloca);
+
+  // Make the new basic block for the loop header, inserting after current
+  // block.
+  BasicBlock *LoopBB = BasicBlock::Create(TheContext, "loop", TheFunction);
+
+  // Insert an explicit fall through from the current block to the LoopBB.
+  Builder.CreateBr(LoopBB);
+
+  // Start insertion in LoopBB.
+  Builder.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 = NamedValues[VarName];
+  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->codegen())
+    return nullptr;
+
+  // Emit the step value.
+  Value *StepVal = nullptr;
+  if (Step) {
+    StepVal = Step->codegen();
+    if (!StepVal)
+      return nullptr;
+  } else {
+    // If not specified, use 1.0.
+    StepVal = ConstantFP::get(TheContext, APFloat(1.0));
+  }
+
+  // Compute the end condition.
+  Value *EndCond = End->codegen();
+  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 = Builder.CreateLoad(Alloca, VarName.c_str());
+  Value *NextVar = Builder.CreateFAdd(CurVar, StepVal, "nextvar");
+  Builder.CreateStore(NextVar, Alloca);
+
+  // Convert condition to a bool by comparing non-equal to 0.0.
+  EndCond = Builder.CreateFCmpONE(
+      EndCond, ConstantFP::get(TheContext, APFloat(0.0)), "loopcond");
+
+  // Create the "after loop" block and insert it.
+  BasicBlock *AfterBB =
+      BasicBlock::Create(TheContext, "afterloop", TheFunction);
+
+  // Insert the conditional branch into the end of LoopEndBB.
+  Builder.CreateCondBr(EndCond, LoopBB, AfterBB);
+
+  // Any new code will be inserted in AfterBB.
+  Builder.SetInsertPoint(AfterBB);
+
+  // Restore the unshadowed variable.
+  if (OldVal)
+    NamedValues[VarName] = OldVal;
+  else
+    NamedValues.erase(VarName);
+
+  // for expr always returns 0.0.
+  return Constant::getNullValue(Type::getDoubleTy(TheContext));
+}
+
+Value *VarExprAST::codegen() {
+  std::vector<AllocaInst *> OldBindings;
+
+  Function *TheFunction = Builder.GetInsertBlock()->getParent();
+
+  // Register all variables and emit their initializer.
+  for (unsigned i = 0, e = VarNames.size(); i != e; ++i) {
+    const std::string &VarName = VarNames[i].first;
+    ExprAST *Init = VarNames[i].second.get();
+
+    // 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->codegen();
+      if (!InitVal)
+        return nullptr;
+    } else { // If not specified, use 0.0.
+      InitVal = ConstantFP::get(TheContext, APFloat(0.0));
+    }
+
+    AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
+    Builder.CreateStore(InitVal, Alloca);
+
+    // Remember the old variable binding so that we can restore the binding when
+    // we unrecurse.
+    OldBindings.push_back(NamedValues[VarName]);
+
+    // Remember this binding.
+    NamedValues[VarName] = Alloca;
+  }
+
+  // Codegen the body, now that all vars are in scope.
+  Value *BodyVal = Body->codegen();
+  if (!BodyVal)
+    return nullptr;
+
+  // Pop all our variables from scope.
+  for (unsigned i = 0, e = VarNames.size(); i != e; ++i)
+    NamedValues[VarNames[i].first] = OldBindings[i];
+
+  // Return the body computation.
+  return BodyVal;
+}
+
+Function *PrototypeAST::codegen() {
+  // Make the function type:  double(double,double) etc.
+  std::vector<Type *> Doubles(Args.size(), Type::getDoubleTy(TheContext));
+  FunctionType *FT =
+      FunctionType::get(Type::getDoubleTy(TheContext), Doubles, false);
+
+  Function *F =
+      Function::Create(FT, Function::ExternalLinkage, Name, TheModule.get());
+
+  // Set names for all arguments.
+  unsigned Idx = 0;
+  for (auto &Arg : F->args())
+    Arg.setName(Args[Idx++]);
+
+  return F;
+}
+
+Function *FunctionAST::codegen() {
+  // Transfer ownership of the prototype to the FunctionProtos map, but keep a
+  // reference to it for use below.
+  auto &P = *Proto;
+  FunctionProtos[Proto->getName()] = std::move(Proto);
+  Function *TheFunction = getFunction(P.getName());
+  if (!TheFunction)
+    return nullptr;
+
+  // If this is an operator, install it.
+  if (P.isBinaryOp())
+    BinopPrecedence[P.getOperatorName()] = P.getBinaryPrecedence();
+
+  // Create a new basic block to start insertion into.
+  BasicBlock *BB = BasicBlock::Create(TheContext, "entry", TheFunction);
+  Builder.SetInsertPoint(BB);
+
+  // Record the function arguments in the NamedValues map.
+  NamedValues.clear();
+  for (auto &Arg : TheFunction->args()) {
+    // Create an alloca for this variable.
+    AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, Arg.getName());
+
+    // Store the initial value into the alloca.
+    Builder.CreateStore(&Arg, Alloca);
+
+    // Add arguments to variable symbol table.
+    NamedValues[std::string(Arg.getName())] = Alloca;
+  }
+
+  if (Value *RetVal = Body->codegen()) {
+    // Finish off the function.
+    Builder.CreateRet(RetVal);
+
+    // Validate the generated code, checking for consistency.
+    verifyFunction(*TheFunction);
+
+    return TheFunction;
+  }
+
+  // Error reading body, remove function.
+  TheFunction->eraseFromParent();
+
+  if (P.isBinaryOp())
+    BinopPrecedence.erase(P.getOperatorName());
+  return nullptr;
+}
+
+//===----------------------------------------------------------------------===//
+// Top-Level parsing and JIT Driver
+//===----------------------------------------------------------------------===//
+
+static void InitializeModuleAndPassManager() {
+  // Open a new module.
+  TheModule = std::make_unique<Module>("my cool jit", TheContext);
+}
+
+static void HandleDefinition() {
+  if (auto FnAST = ParseDefinition()) {
+    if (auto *FnIR = FnAST->codegen()) {
+      fprintf(stderr, "Read function definition:");
+      FnIR->print(errs());
+      fprintf(stderr, "\n");
+    }
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+static void HandleExtern() {
+  if (auto ProtoAST = ParseExtern()) {
+    if (auto *FnIR = ProtoAST->codegen()) {
+      fprintf(stderr, "Read extern: ");
+      FnIR->print(errs());
+      fprintf(stderr, "\n");
+      FunctionProtos[ProtoAST->getName()] = std::move(ProtoAST);
+    }
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+static void HandleTopLevelExpression() {
+  // Evaluate a top-level expression into an anonymous function.
+  if (auto FnAST = ParseTopLevelExpr()) {
+    FnAST->codegen();
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+/// top ::= definition | external | expression | ';'
+static void MainLoop() {
+  while (true) {
+    switch (CurTok) {
+    case tok_eof:
+      return;
+    case ';': // ignore top-level semicolons.
+      getNextToken();
+      break;
+    case tok_def:
+      HandleDefinition();
+      break;
+    case tok_extern:
+      HandleExtern();
+      break;
+    default:
+      HandleTopLevelExpression();
+      break;
+    }
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// "Library" functions that can be "extern'd" from user code.
+//===----------------------------------------------------------------------===//
+
+#ifdef _WIN32
+#define DLLEXPORT __declspec(dllexport)
+#else
+#define DLLEXPORT
+#endif
+
+/// putchard - putchar that takes a double and returns 0.
+extern "C" DLLEXPORT double putchard(double X) {
+  fputc((char)X, stderr);
+  return 0;
+}
+
+/// printd - printf that takes a double prints it as "%f\n", returning 0.
+extern "C" DLLEXPORT double printd(double X) {
+  fprintf(stderr, "%f\n", X);
+  return 0;
+}
+
+//===----------------------------------------------------------------------===//
+// Main driver code.
+//===----------------------------------------------------------------------===//
+
+int main() {
+  // Install standard binary operators.
+  // 1 is lowest precedence.
+  BinopPrecedence['<'] = 10;
+  BinopPrecedence['+'] = 20;
+  BinopPrecedence['-'] = 20;
+  BinopPrecedence['*'] = 40; // highest.
+
+  // Prime the first token.
+  fprintf(stderr, "ready> ");
+  getNextToken();
+
+  InitializeModuleAndPassManager();
+
+  // Run the main "interpreter loop" now.
+  MainLoop();
+
+  // Initialize the target registry etc.
+  InitializeAllTargetInfos();
+  InitializeAllTargets();
+  InitializeAllTargetMCs();
+  InitializeAllAsmParsers();
+  InitializeAllAsmPrinters();
+
+  auto TargetTriple = sys::getDefaultTargetTriple();
+  TheModule->setTargetTriple(TargetTriple);
+
+  std::string Error;
+  auto Target = TargetRegistry::lookupTarget(TargetTriple, Error);
+
+  // Print an error and exit if we couldn't find the requested target.
+  // This generally occurs if we've forgotten to initialise the
+  // TargetRegistry or we have a bogus target triple.
+  if (!Target) {
+    errs() << Error;
+    return 1;
+  }
+
+  auto CPU = "generic";
+  auto Features = "";
+
+  TargetOptions opt;
+  auto RM = Optional<Reloc::Model>();
+  auto TheTargetMachine =
+      Target->createTargetMachine(TargetTriple, CPU, Features, opt, RM);
+
+  TheModule->setDataLayout(TheTargetMachine->createDataLayout());
+
+// THIS LINE CHANGED FOR THE h_da FbI VERSION!
+  auto Filename = "test8.o";
+  std::error_code EC;
+  raw_fd_ostream dest(Filename, EC, sys::fs::OF_None);
+
+  if (EC) {
+    errs() << "Could not open file: " << EC.message();
+    return 1;
+  }
+
+  legacy::PassManager pass;
+  auto FileType = CGFT_ObjectFile;
+
+  if (TheTargetMachine->addPassesToEmitFile(pass, dest, nullptr, FileType)) {
+    errs() << "TheTargetMachine can't emit a file of this type";
+    return 1;
+  }
+
+  pass.run(*TheModule);
+  dest.flush();
+
+  outs() << "Wrote " << Filename << "\n";
+
+  return 0;
+}
diff --git a/LLVM/cplusplus/toy9.cpp b/LLVM/cplusplus/toy9.cpp
new file mode 100644
index 0000000..ea134cd
--- /dev/null
+++ b/LLVM/cplusplus/toy9.cpp
@@ -0,0 +1,1452 @@
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/Analysis/BasicAliasAnalysis.h"
+#include "llvm/Analysis/Passes.h"
+#include "llvm/IR/DIBuilder.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/LegacyPassManager.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Verifier.h"
+#include "llvm/Support/Host.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Transforms/Scalar.h"
+#include <cctype>
+#include <cstdio>
+#include <map>
+#include <string>
+#include <vector>
+// Next Line modified for the FbI/h_da.de version (only)
+#include "KaleidoscopeJIT.h"
+
+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
+};
+
+std::string getTokName(int Tok) {
+  switch (Tok) {
+  case tok_eof:
+    return "eof";
+  case tok_def:
+    return "def";
+  case tok_extern:
+    return "extern";
+  case tok_identifier:
+    return "identifier";
+  case tok_number:
+    return "number";
+  case tok_if:
+    return "if";
+  case tok_then:
+    return "then";
+  case tok_else:
+    return "else";
+  case tok_for:
+    return "for";
+  case tok_in:
+    return "in";
+  case tok_binary:
+    return "binary";
+  case tok_unary:
+    return "unary";
+  case tok_var:
+    return "var";
+  }
+  return std::string(1, (char)Tok);
+}
+
+namespace {
+class PrototypeAST;
+class ExprAST;
+}
+static LLVMContext TheContext;
+static IRBuilder<> Builder(TheContext);
+struct DebugInfo {
+  DICompileUnit *TheCU;
+  DIType *DblTy;
+  std::vector<DIScope *> LexicalBlocks;
+
+  void emitLocation(ExprAST *AST);
+  DIType *getDoubleTy();
+} KSDbgInfo;
+
+struct SourceLocation {
+  int Line;
+  int Col;
+};
+static SourceLocation CurLoc;
+static SourceLocation LexLoc = {1, 0};
+
+static int advance() {
+  int LastChar = getchar();
+
+  if (LastChar == '\n' || LastChar == '\r') {
+    LexLoc.Line++;
+    LexLoc.Col = 0;
+  } else
+    LexLoc.Col++;
+  return LastChar;
+}
+
+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 = advance();
+
+  CurLoc = LexLoc;
+
+  if (isalpha(LastChar)) { // identifier: [a-zA-Z][a-zA-Z0-9]*
+    IdentifierStr = LastChar;
+    while (isalnum((LastChar = advance())))
+      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 = advance();
+    } while (isdigit(LastChar) || LastChar == '.');
+
+    NumVal = strtod(NumStr.c_str(), nullptr);
+    return tok_number;
+  }
+
+  if (LastChar == '#') {
+    // Comment until end of line.
+    do
+      LastChar = advance();
+    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 = advance();
+  return ThisChar;
+}
+
+//===----------------------------------------------------------------------===//
+// Abstract Syntax Tree (aka Parse Tree)
+//===----------------------------------------------------------------------===//
+namespace {
+
+raw_ostream &indent(raw_ostream &O, int size) {
+  return O << std::string(size, ' ');
+}
+
+/// ExprAST - Base class for all expression nodes.
+class ExprAST {
+  SourceLocation Loc;
+
+public:
+  ExprAST(SourceLocation Loc = CurLoc) : Loc(Loc) {}
+  virtual ~ExprAST() {}
+  virtual Value *codegen() = 0;
+  int getLine() const { return Loc.Line; }
+  int getCol() const { return Loc.Col; }
+  virtual raw_ostream &dump(raw_ostream &out, int ind) {
+    return out << ':' << getLine() << ':' << getCol() << '\n';
+  }
+};
+
+/// NumberExprAST - Expression class for numeric literals like "1.0".
+class NumberExprAST : public ExprAST {
+  double Val;
+
+public:
+  NumberExprAST(double Val) : Val(Val) {}
+  raw_ostream &dump(raw_ostream &out, int ind) override {
+    return ExprAST::dump(out << Val, ind);
+  }
+  Value *codegen() override;
+};
+
+/// VariableExprAST - Expression class for referencing a variable, like "a".
+class VariableExprAST : public ExprAST {
+  std::string Name;
+
+public:
+  VariableExprAST(SourceLocation Loc, const std::string &Name)
+      : ExprAST(Loc), Name(Name) {}
+  const std::string &getName() const { return Name; }
+  Value *codegen() override;
+  raw_ostream &dump(raw_ostream &out, int ind) override {
+    return ExprAST::dump(out << Name, ind);
+  }
+};
+
+/// UnaryExprAST - Expression class for a unary operator.
+class UnaryExprAST : public ExprAST {
+  char Opcode;
+  std::unique_ptr<ExprAST> Operand;
+
+public:
+  UnaryExprAST(char Opcode, std::unique_ptr<ExprAST> Operand)
+      : Opcode(Opcode), Operand(std::move(Operand)) {}
+  Value *codegen() override;
+  raw_ostream &dump(raw_ostream &out, int ind) override {
+    ExprAST::dump(out << "unary" << Opcode, ind);
+    Operand->dump(out, ind + 1);
+    return out;
+  }
+};
+
+/// BinaryExprAST - Expression class for a binary operator.
+class BinaryExprAST : public ExprAST {
+  char Op;
+  std::unique_ptr<ExprAST> LHS, RHS;
+
+public:
+  BinaryExprAST(SourceLocation Loc, char Op, std::unique_ptr<ExprAST> LHS,
+                std::unique_ptr<ExprAST> RHS)
+      : ExprAST(Loc), Op(Op), LHS(std::move(LHS)), RHS(std::move(RHS)) {}
+  Value *codegen() override;
+  raw_ostream &dump(raw_ostream &out, int ind) override {
+    ExprAST::dump(out << "binary" << Op, ind);
+    LHS->dump(indent(out, ind) << "LHS:", ind + 1);
+    RHS->dump(indent(out, ind) << "RHS:", ind + 1);
+    return out;
+  }
+};
+
+/// CallExprAST - Expression class for function calls.
+class CallExprAST : public ExprAST {
+  std::string Callee;
+  std::vector<std::unique_ptr<ExprAST>> Args;
+
+public:
+  CallExprAST(SourceLocation Loc, const std::string &Callee,
+              std::vector<std::unique_ptr<ExprAST>> Args)
+      : ExprAST(Loc), Callee(Callee), Args(std::move(Args)) {}
+  Value *codegen() override;
+  raw_ostream &dump(raw_ostream &out, int ind) override {
+    ExprAST::dump(out << "call " << Callee, ind);
+    for (const auto &Arg : Args)
+      Arg->dump(indent(out, ind + 1), ind + 1);
+    return out;
+  }
+};
+
+/// IfExprAST - Expression class for if/then/else.
+class IfExprAST : public ExprAST {
+  std::unique_ptr<ExprAST> Cond, Then, Else;
+
+public:
+  IfExprAST(SourceLocation Loc, std::unique_ptr<ExprAST> Cond,
+            std::unique_ptr<ExprAST> Then, std::unique_ptr<ExprAST> Else)
+      : ExprAST(Loc), Cond(std::move(Cond)), Then(std::move(Then)),
+        Else(std::move(Else)) {}
+  Value *codegen() override;
+  raw_ostream &dump(raw_ostream &out, int ind) override {
+    ExprAST::dump(out << "if", ind);
+    Cond->dump(indent(out, ind) << "Cond:", ind + 1);
+    Then->dump(indent(out, ind) << "Then:", ind + 1);
+    Else->dump(indent(out, ind) << "Else:", ind + 1);
+    return out;
+  }
+};
+
+/// ForExprAST - Expression class for for/in.
+class ForExprAST : public ExprAST {
+  std::string VarName;
+  std::unique_ptr<ExprAST> Start, End, Step, Body;
+
+public:
+  ForExprAST(const std::string &VarName, std::unique_ptr<ExprAST> Start,
+             std::unique_ptr<ExprAST> End, std::unique_ptr<ExprAST> Step,
+             std::unique_ptr<ExprAST> Body)
+      : VarName(VarName), Start(std::move(Start)), End(std::move(End)),
+        Step(std::move(Step)), Body(std::move(Body)) {}
+  Value *codegen() override;
+  raw_ostream &dump(raw_ostream &out, int ind) override {
+    ExprAST::dump(out << "for", ind);
+    Start->dump(indent(out, ind) << "Cond:", ind + 1);
+    End->dump(indent(out, ind) << "End:", ind + 1);
+    Step->dump(indent(out, ind) << "Step:", ind + 1);
+    Body->dump(indent(out, ind) << "Body:", ind + 1);
+    return out;
+  }
+};
+
+/// VarExprAST - Expression class for var/in
+class VarExprAST : public ExprAST {
+  std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames;
+  std::unique_ptr<ExprAST> Body;
+
+public:
+  VarExprAST(
+      std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames,
+      std::unique_ptr<ExprAST> Body)
+      : VarNames(std::move(VarNames)), Body(std::move(Body)) {}
+  Value *codegen() override;
+  raw_ostream &dump(raw_ostream &out, int ind) override {
+    ExprAST::dump(out << "var", ind);
+    for (const auto &NamedVar : VarNames)
+      NamedVar.second->dump(indent(out, ind) << NamedVar.first << ':', ind + 1);
+    Body->dump(indent(out, ind) << "Body:", ind + 1);
+    return out;
+  }
+};
+
+/// PrototypeAST - This class represents the "prototype" for a function,
+/// which captures its name, and its argument names (thus implicitly the number
+/// of arguments the function takes), as well as if it is an operator.
+class PrototypeAST {
+  std::string Name;
+  std::vector<std::string> Args;
+  bool IsOperator;
+  unsigned Precedence; // Precedence if a binary op.
+  int Line;
+
+public:
+  PrototypeAST(SourceLocation Loc, const std::string &Name,
+               std::vector<std::string> Args, bool IsOperator = false,
+               unsigned Prec = 0)
+      : Name(Name), Args(std::move(Args)), IsOperator(IsOperator),
+        Precedence(Prec), Line(Loc.Line) {}
+  Function *codegen();
+  const std::string &getName() const { return Name; }
+
+  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];
+  }
+
+  unsigned getBinaryPrecedence() const { return Precedence; }
+  int getLine() const { return Line; }
+};
+
+/// FunctionAST - This class represents a function definition itself.
+class FunctionAST {
+  std::unique_ptr<PrototypeAST> Proto;
+  std::unique_ptr<ExprAST> Body;
+
+public:
+  FunctionAST(std::unique_ptr<PrototypeAST> Proto,
+              std::unique_ptr<ExprAST> Body)
+      : Proto(std::move(Proto)), Body(std::move(Body)) {}
+  Function *codegen();
+  raw_ostream &dump(raw_ostream &out, int ind) {
+    indent(out, ind) << "FunctionAST\n";
+    ++ind;
+    indent(out, ind) << "Body:";
+    return Body ? Body->dump(out, ind) : out << "null\n";
+  }
+};
+} // end anonymous namespace
+
+//===----------------------------------------------------------------------===//
+// 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;
+}
+
+/// LogError* - These are little helper functions for error handling.
+std::unique_ptr<ExprAST> LogError(const char *Str) {
+  fprintf(stderr, "Error: %s\n", Str);
+  return nullptr;
+}
+
+std::unique_ptr<PrototypeAST> LogErrorP(const char *Str) {
+  LogError(Str);
+  return nullptr;
+}
+
+static std::unique_ptr<ExprAST> ParseExpression();
+
+/// numberexpr ::= number
+static std::unique_ptr<ExprAST> ParseNumberExpr() {
+  auto Result = std::make_unique<NumberExprAST>(NumVal);
+  getNextToken(); // consume the number
+  return std::move(Result);
+}
+
+/// parenexpr ::= '(' expression ')'
+static std::unique_ptr<ExprAST> ParseParenExpr() {
+  getNextToken(); // eat (.
+  auto V = ParseExpression();
+  if (!V)
+    return nullptr;
+
+  if (CurTok != ')')
+    return LogError("expected ')'");
+  getNextToken(); // eat ).
+  return V;
+}
+
+/// identifierexpr
+///   ::= identifier
+///   ::= identifier '(' expression* ')'
+static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
+  std::string IdName = IdentifierStr;
+
+  SourceLocation LitLoc = CurLoc;
+
+  getNextToken(); // eat identifier.
+
+  if (CurTok != '(') // Simple variable ref.
+    return std::make_unique<VariableExprAST>(LitLoc, IdName);
+
+  // Call.
+  getNextToken(); // eat (
+  std::vector<std::unique_ptr<ExprAST>> Args;
+  if (CurTok != ')') {
+    while (1) {
+      if (auto Arg = ParseExpression())
+        Args.push_back(std::move(Arg));
+      else
+        return nullptr;
+
+      if (CurTok == ')')
+        break;
+
+      if (CurTok != ',')
+        return LogError("Expected ')' or ',' in argument list");
+      getNextToken();
+    }
+  }
+
+  // Eat the ')'.
+  getNextToken();
+
+  return std::make_unique<CallExprAST>(LitLoc, IdName, std::move(Args));
+}
+
+/// ifexpr ::= 'if' expression 'then' expression 'else' expression
+static std::unique_ptr<ExprAST> ParseIfExpr() {
+  SourceLocation IfLoc = CurLoc;
+
+  getNextToken(); // eat the if.
+
+  // condition.
+  auto Cond = ParseExpression();
+  if (!Cond)
+    return nullptr;
+
+  if (CurTok != tok_then)
+    return LogError("expected then");
+  getNextToken(); // eat the then
+
+  auto Then = ParseExpression();
+  if (!Then)
+    return nullptr;
+
+  if (CurTok != tok_else)
+    return LogError("expected else");
+
+  getNextToken();
+
+  auto Else = ParseExpression();
+  if (!Else)
+    return nullptr;
+
+  return std::make_unique<IfExprAST>(IfLoc, std::move(Cond), std::move(Then),
+                                      std::move(Else));
+}
+
+/// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression
+static std::unique_ptr<ExprAST> ParseForExpr() {
+  getNextToken(); // eat the for.
+
+  if (CurTok != tok_identifier)
+    return LogError("expected identifier after for");
+
+  std::string IdName = IdentifierStr;
+  getNextToken(); // eat identifier.
+
+  if (CurTok != '=')
+    return LogError("expected '=' after for");
+  getNextToken(); // eat '='.
+
+  auto Start = ParseExpression();
+  if (!Start)
+    return nullptr;
+  if (CurTok != ',')
+    return LogError("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 LogError("expected 'in' after for");
+  getNextToken(); // eat 'in'.
+
+  auto Body = ParseExpression();
+  if (!Body)
+    return nullptr;
+
+  return std::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<ExprAST> ParseVarExpr() {
+  getNextToken(); // eat the var.
+
+  std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames;
+
+  // At least one variable name is required.
+  if (CurTok != tok_identifier)
+    return LogError("expected identifier after var");
+
+  while (1) {
+    std::string Name = IdentifierStr;
+    getNextToken(); // eat identifier.
+
+    // Read the optional initializer.
+    std::unique_ptr<ExprAST> Init = nullptr;
+    if (CurTok == '=') {
+      getNextToken(); // eat the '='.
+
+      Init = ParseExpression();
+      if (!Init)
+        return nullptr;
+    }
+
+    VarNames.push_back(std::make_pair(Name, std::move(Init)));
+
+    // End of var list, exit loop.
+    if (CurTok != ',')
+      break;
+    getNextToken(); // eat the ','.
+
+    if (CurTok != tok_identifier)
+      return LogError("expected identifier list after var");
+  }
+
+  // At this point, we have to have 'in'.
+  if (CurTok != tok_in)
+    return LogError("expected 'in' keyword after 'var'");
+  getNextToken(); // eat 'in'.
+
+  auto Body = ParseExpression();
+  if (!Body)
+    return nullptr;
+
+  return std::make_unique<VarExprAST>(std::move(VarNames), std::move(Body));
+}
+
+/// primary
+///   ::= identifierexpr
+///   ::= numberexpr
+///   ::= parenexpr
+///   ::= ifexpr
+///   ::= forexpr
+///   ::= varexpr
+static std::unique_ptr<ExprAST> ParsePrimary() {
+  switch (CurTok) {
+  default:
+    return LogError("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 std::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 (1) {
+    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;
+    SourceLocation BinLoc = CurLoc;
+    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 = std::make_unique<BinaryExprAST>(BinLoc, 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;
+
+  SourceLocation FnLoc = CurLoc;
+
+  unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.
+  unsigned BinaryPrecedence = 30;
+
+  switch (CurTok) {
+  default:
+    return LogErrorP("Expected function name in prototype");
+  case tok_identifier:
+    FnName = IdentifierStr;
+    Kind = 0;
+    getNextToken();
+    break;
+  case tok_unary:
+    getNextToken();
+    if (!isascii(CurTok))
+      return LogErrorP("Expected unary operator");
+    FnName = "unary";
+    FnName += (char)CurTok;
+    Kind = 1;
+    getNextToken();
+    break;
+  case tok_binary:
+    getNextToken();
+    if (!isascii(CurTok))
+      return LogErrorP("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 LogErrorP("Invalid precedence: must be 1..100");
+      BinaryPrecedence = (unsigned)NumVal;
+      getNextToken();
+    }
+    break;
+  }
+
+  if (CurTok != '(')
+    return LogErrorP("Expected '(' in prototype");
+
+  std::vector<std::string> ArgNames;
+  while (getNextToken() == tok_identifier)
+    ArgNames.push_back(IdentifierStr);
+  if (CurTok != ')')
+    return LogErrorP("Expected ')' in prototype");
+
+  // success.
+  getNextToken(); // eat ')'.
+
+  // Verify right number of names for operator.
+  if (Kind && ArgNames.size() != Kind)
+    return LogErrorP("Invalid number of operands for operator");
+
+  return std::make_unique<PrototypeAST>(FnLoc, FnName, 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 E = ParseExpression())
+    return std::make_unique<FunctionAST>(std::move(Proto), std::move(E));
+  return nullptr;
+}
+
+/// toplevelexpr ::= expression
+static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
+  SourceLocation FnLoc = CurLoc;
+  if (auto E = ParseExpression()) {
+    // Make an anonymous proto.
+    auto Proto = std::make_unique<PrototypeAST>(FnLoc, "__anon_expr",
+                                                 std::vector<std::string>());
+    return std::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();
+}
+
+//===----------------------------------------------------------------------===//
+// Debug Info Support
+//===----------------------------------------------------------------------===//
+
+static std::unique_ptr<DIBuilder> DBuilder;
+
+DIType *DebugInfo::getDoubleTy() {
+  if (DblTy)
+    return DblTy;
+
+  DblTy = DBuilder->createBasicType("double", 64, dwarf::DW_ATE_float);
+  return DblTy;
+}
+
+void DebugInfo::emitLocation(ExprAST *AST) {
+  if (!AST)
+    return Builder.SetCurrentDebugLocation(DebugLoc());
+  DIScope *Scope;
+  if (LexicalBlocks.empty())
+    Scope = TheCU;
+  else
+    Scope = LexicalBlocks.back();
+  Builder.SetCurrentDebugLocation(
+      DebugLoc::get(AST->getLine(), AST->getCol(), Scope));
+}
+
+static DISubroutineType *CreateFunctionType(unsigned NumArgs, DIFile *Unit) {
+  SmallVector<Metadata *, 8> EltTys;
+  DIType *DblTy = KSDbgInfo.getDoubleTy();
+
+  // Add the result type.
+  EltTys.push_back(DblTy);
+
+  for (unsigned i = 0, e = NumArgs; i != e; ++i)
+    EltTys.push_back(DblTy);
+
+  return DBuilder->createSubroutineType(DBuilder->getOrCreateTypeArray(EltTys));
+}
+
+//===----------------------------------------------------------------------===//
+// Code Generation
+//===----------------------------------------------------------------------===//
+
+static std::unique_ptr<Module> TheModule;
+static std::map<std::string, AllocaInst *> NamedValues;
+static std::unique_ptr<KaleidoscopeJIT> TheJIT;
+static std::map<std::string, std::unique_ptr<PrototypeAST>> FunctionProtos;
+
+Value *LogErrorV(const char *Str) {
+  LogError(Str);
+  return nullptr;
+}
+
+Function *getFunction(std::string Name) {
+  // First, see if the function has already been added to the current module.
+  if (auto *F = TheModule->getFunction(Name))
+    return F;
+
+  // If not, check whether we can codegen the declaration from some existing
+  // prototype.
+  auto FI = FunctionProtos.find(Name);
+  if (FI != FunctionProtos.end())
+    return FI->second->codegen();
+
+  // If no existing prototype exists, return null.
+  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,
+                                          StringRef VarName) {
+  IRBuilder<> TmpB(&TheFunction->getEntryBlock(),
+                   TheFunction->getEntryBlock().begin());
+  return TmpB.CreateAlloca(Type::getDoubleTy(TheContext), nullptr, VarName);
+}
+
+Value *NumberExprAST::codegen() {
+  KSDbgInfo.emitLocation(this);
+  return ConstantFP::get(TheContext, APFloat(Val));
+}
+
+Value *VariableExprAST::codegen() {
+  // Look this variable up in the function.
+  Value *V = NamedValues[Name];
+  if (!V)
+    return LogErrorV("Unknown variable name");
+
+  KSDbgInfo.emitLocation(this);
+  // Load the value.
+  return Builder.CreateLoad(V, Name.c_str());
+}
+
+Value *UnaryExprAST::codegen() {
+  Value *OperandV = Operand->codegen();
+  if (!OperandV)
+    return nullptr;
+
+  Function *F = getFunction(std::string("unary") + Opcode);
+  if (!F)
+    return LogErrorV("Unknown unary operator");
+
+  KSDbgInfo.emitLocation(this);
+  return Builder.CreateCall(F, OperandV, "unop");
+}
+
+Value *BinaryExprAST::codegen() {
+  KSDbgInfo.emitLocation(this);
+
+  // Special case '=' because we don't want to emit the LHS as an expression.
+  if (Op == '=') {
+    // Assignment requires the LHS to be an identifier.
+    // This assume we're building without RTTI because LLVM builds that way by
+    // default.  If you build LLVM with RTTI this can be changed to a
+    // dynamic_cast for automatic error checking.
+    VariableExprAST *LHSE = static_cast<VariableExprAST *>(LHS.get());
+    if (!LHSE)
+      return LogErrorV("destination of '=' must be a variable");
+    // Codegen the RHS.
+    Value *Val = RHS->codegen();
+    if (!Val)
+      return nullptr;
+
+    // Look up the name.
+    Value *Variable = NamedValues[LHSE->getName()];
+    if (!Variable)
+      return LogErrorV("Unknown variable name");
+
+    Builder.CreateStore(Val, Variable);
+    return Val;
+  }
+
+  Value *L = LHS->codegen();
+  Value *R = RHS->codegen();
+  if (!L || !R)
+    return nullptr;
+
+  switch (Op) {
+  case '+':
+    return Builder.CreateFAdd(L, R, "addtmp");
+  case '-':
+    return Builder.CreateFSub(L, R, "subtmp");
+  case '*':
+    return Builder.CreateFMul(L, R, "multmp");
+  case '<':
+    L = Builder.CreateFCmpULT(L, R, "cmptmp");
+    // Convert bool 0/1 to double 0.0 or 1.0
+    return Builder.CreateUIToFP(L, Type::getDoubleTy(TheContext), "booltmp");
+  default:
+    break;
+  }
+
+  // If it wasn't a builtin binary operator, it must be a user defined one. Emit
+  // a call to it.
+  Function *F = getFunction(std::string("binary") + Op);
+  assert(F && "binary operator not found!");
+
+  Value *Ops[] = {L, R};
+  return Builder.CreateCall(F, Ops, "binop");
+}
+
+Value *CallExprAST::codegen() {
+  KSDbgInfo.emitLocation(this);
+
+  // Look up the name in the global module table.
+  Function *CalleeF = getFunction(Callee);
+  if (!CalleeF)
+    return LogErrorV("Unknown function referenced");
+
+  // If argument mismatch error.
+  if (CalleeF->arg_size() != Args.size())
+    return LogErrorV("Incorrect # arguments passed");
+
+  std::vector<Value *> ArgsV;
+  for (unsigned i = 0, e = Args.size(); i != e; ++i) {
+    ArgsV.push_back(Args[i]->codegen());
+    if (!ArgsV.back())
+      return nullptr;
+  }
+
+  return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
+}
+
+Value *IfExprAST::codegen() {
+  KSDbgInfo.emitLocation(this);
+
+  Value *CondV = Cond->codegen();
+  if (!CondV)
+    return nullptr;
+
+  // Convert condition to a bool by comparing non-equal to 0.0.
+  CondV = Builder.CreateFCmpONE(
+      CondV, ConstantFP::get(TheContext, APFloat(0.0)), "ifcond");
+
+  Function *TheFunction = Builder.GetInsertBlock()->getParent();
+
+  // Create blocks for the then and else cases.  Insert the 'then' block at the
+  // end of the function.
+  BasicBlock *ThenBB = BasicBlock::Create(TheContext, "then", TheFunction);
+  BasicBlock *ElseBB = BasicBlock::Create(TheContext, "else");
+  BasicBlock *MergeBB = BasicBlock::Create(TheContext, "ifcont");
+
+  Builder.CreateCondBr(CondV, ThenBB, ElseBB);
+
+  // Emit then value.
+  Builder.SetInsertPoint(ThenBB);
+
+  Value *ThenV = Then->codegen();
+  if (!ThenV)
+    return nullptr;
+
+  Builder.CreateBr(MergeBB);
+  // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
+  ThenBB = Builder.GetInsertBlock();
+
+  // Emit else block.
+  TheFunction->getBasicBlockList().push_back(ElseBB);
+  Builder.SetInsertPoint(ElseBB);
+
+  Value *ElseV = Else->codegen();
+  if (!ElseV)
+    return nullptr;
+
+  Builder.CreateBr(MergeBB);
+  // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
+  ElseBB = Builder.GetInsertBlock();
+
+  // Emit merge block.
+  TheFunction->getBasicBlockList().push_back(MergeBB);
+  Builder.SetInsertPoint(MergeBB);
+  PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(TheContext), 2, "iftmp");
+
+  PN->addIncoming(ThenV, ThenBB);
+  PN->addIncoming(ElseV, ElseBB);
+  return PN;
+}
+
+// Output for-loop 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:
+Value *ForExprAST::codegen() {
+  Function *TheFunction = Builder.GetInsertBlock()->getParent();
+
+  // Create an alloca for the variable in the entry block.
+  AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
+
+  KSDbgInfo.emitLocation(this);
+
+  // Emit the start code first, without 'variable' in scope.
+  Value *StartVal = Start->codegen();
+  if (!StartVal)
+    return nullptr;
+
+  // Store the value into the alloca.
+  Builder.CreateStore(StartVal, Alloca);
+
+  // Make the new basic block for the loop header, inserting after current
+  // block.
+  BasicBlock *LoopBB = BasicBlock::Create(TheContext, "loop", TheFunction);
+
+  // Insert an explicit fall through from the current block to the LoopBB.
+  Builder.CreateBr(LoopBB);
+
+  // Start insertion in LoopBB.
+  Builder.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 = NamedValues[VarName];
+  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->codegen())
+    return nullptr;
+
+  // Emit the step value.
+  Value *StepVal = nullptr;
+  if (Step) {
+    StepVal = Step->codegen();
+    if (!StepVal)
+      return nullptr;
+  } else {
+    // If not specified, use 1.0.
+    StepVal = ConstantFP::get(TheContext, APFloat(1.0));
+  }
+
+  // Compute the end condition.
+  Value *EndCond = End->codegen();
+  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 = Builder.CreateLoad(Alloca, VarName.c_str());
+  Value *NextVar = Builder.CreateFAdd(CurVar, StepVal, "nextvar");
+  Builder.CreateStore(NextVar, Alloca);
+
+  // Convert condition to a bool by comparing non-equal to 0.0.
+  EndCond = Builder.CreateFCmpONE(
+      EndCond, ConstantFP::get(TheContext, APFloat(0.0)), "loopcond");
+
+  // Create the "after loop" block and insert it.
+  BasicBlock *AfterBB =
+      BasicBlock::Create(TheContext, "afterloop", TheFunction);
+
+  // Insert the conditional branch into the end of LoopEndBB.
+  Builder.CreateCondBr(EndCond, LoopBB, AfterBB);
+
+  // Any new code will be inserted in AfterBB.
+  Builder.SetInsertPoint(AfterBB);
+
+  // Restore the unshadowed variable.
+  if (OldVal)
+    NamedValues[VarName] = OldVal;
+  else
+    NamedValues.erase(VarName);
+
+  // for expr always returns 0.0.
+  return Constant::getNullValue(Type::getDoubleTy(TheContext));
+}
+
+Value *VarExprAST::codegen() {
+  std::vector<AllocaInst *> OldBindings;
+
+  Function *TheFunction = Builder.GetInsertBlock()->getParent();
+
+  // Register all variables and emit their initializer.
+  for (unsigned i = 0, e = VarNames.size(); i != e; ++i) {
+    const std::string &VarName = VarNames[i].first;
+    ExprAST *Init = VarNames[i].second.get();
+
+    // 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->codegen();
+      if (!InitVal)
+        return nullptr;
+    } else { // If not specified, use 0.0.
+      InitVal = ConstantFP::get(TheContext, APFloat(0.0));
+    }
+
+    AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
+    Builder.CreateStore(InitVal, Alloca);
+
+    // Remember the old variable binding so that we can restore the binding when
+    // we unrecurse.
+    OldBindings.push_back(NamedValues[VarName]);
+
+    // Remember this binding.
+    NamedValues[VarName] = Alloca;
+  }
+
+  KSDbgInfo.emitLocation(this);
+
+  // Codegen the body, now that all vars are in scope.
+  Value *BodyVal = Body->codegen();
+  if (!BodyVal)
+    return nullptr;
+
+  // Pop all our variables from scope.
+  for (unsigned i = 0, e = VarNames.size(); i != e; ++i)
+    NamedValues[VarNames[i].first] = OldBindings[i];
+
+  // Return the body computation.
+  return BodyVal;
+}
+
+Function *PrototypeAST::codegen() {
+  // Make the function type:  double(double,double) etc.
+  std::vector<Type *> Doubles(Args.size(), Type::getDoubleTy(TheContext));
+  FunctionType *FT =
+      FunctionType::get(Type::getDoubleTy(TheContext), Doubles, false);
+
+  Function *F =
+      Function::Create(FT, Function::ExternalLinkage, Name, TheModule.get());
+
+  // Set names for all arguments.
+  unsigned Idx = 0;
+  for (auto &Arg : F->args())
+    Arg.setName(Args[Idx++]);
+
+  return F;
+}
+
+Function *FunctionAST::codegen() {
+  // Transfer ownership of the prototype to the FunctionProtos map, but keep a
+  // reference to it for use below.
+  auto &P = *Proto;
+  FunctionProtos[Proto->getName()] = std::move(Proto);
+  Function *TheFunction = getFunction(P.getName());
+  if (!TheFunction)
+    return nullptr;
+
+  // If this is an operator, install it.
+  if (P.isBinaryOp())
+    BinopPrecedence[P.getOperatorName()] = P.getBinaryPrecedence();
+
+  // Create a new basic block to start insertion into.
+  BasicBlock *BB = BasicBlock::Create(TheContext, "entry", TheFunction);
+  Builder.SetInsertPoint(BB);
+
+  // Create a subprogram DIE for this function.
+  DIFile *Unit = DBuilder->createFile(KSDbgInfo.TheCU->getFilename(),
+                                      KSDbgInfo.TheCU->getDirectory());
+  DIScope *FContext = Unit;
+  unsigned LineNo = P.getLine();
+  unsigned ScopeLine = LineNo;
+  DISubprogram *SP = DBuilder->createFunction(
+      FContext, P.getName(), StringRef(), Unit, LineNo,
+      CreateFunctionType(TheFunction->arg_size(), Unit), ScopeLine,
+      DINode::FlagPrototyped, DISubprogram::SPFlagDefinition);
+  TheFunction->setSubprogram(SP);
+
+  // Push the current scope.
+  KSDbgInfo.LexicalBlocks.push_back(SP);
+
+  // Unset the location for the prologue emission (leading instructions with no
+  // location in a function are considered part of the prologue and the debugger
+  // will run past them when breaking on a function)
+  KSDbgInfo.emitLocation(nullptr);
+
+  // Record the function arguments in the NamedValues map.
+  NamedValues.clear();
+  unsigned ArgIdx = 0;
+  for (auto &Arg : TheFunction->args()) {
+    // Create an alloca for this variable.
+    AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, Arg.getName());
+
+    // Create a debug descriptor for the variable.
+    DILocalVariable *D = DBuilder->createParameterVariable(
+        SP, Arg.getName(), ++ArgIdx, Unit, LineNo, KSDbgInfo.getDoubleTy(),
+        true);
+
+    DBuilder->insertDeclare(Alloca, D, DBuilder->createExpression(),
+                            DebugLoc::get(LineNo, 0, SP),
+                            Builder.GetInsertBlock());
+
+    // Store the initial value into the alloca.
+    Builder.CreateStore(&Arg, Alloca);
+
+    // Add arguments to variable symbol table.
+    NamedValues[std::string(Arg.getName())] = Alloca;
+  }
+
+  KSDbgInfo.emitLocation(Body.get());
+
+  if (Value *RetVal = Body->codegen()) {
+    // Finish off the function.
+    Builder.CreateRet(RetVal);
+
+    // Pop off the lexical block for the function.
+    KSDbgInfo.LexicalBlocks.pop_back();
+
+    // Validate the generated code, checking for consistency.
+    verifyFunction(*TheFunction);
+
+    return TheFunction;
+  }
+
+  // Error reading body, remove function.
+  TheFunction->eraseFromParent();
+
+  if (P.isBinaryOp())
+    BinopPrecedence.erase(Proto->getOperatorName());
+
+  // Pop off the lexical block for the function since we added it
+  // unconditionally.
+  KSDbgInfo.LexicalBlocks.pop_back();
+
+  return nullptr;
+}
+
+//===----------------------------------------------------------------------===//
+// Top-Level parsing and JIT Driver
+//===----------------------------------------------------------------------===//
+
+static void InitializeModule() {
+  // Open a new module.
+  TheModule = std::make_unique<Module>("my cool jit", TheContext);
+  TheModule->setDataLayout(TheJIT->getTargetMachine().createDataLayout());
+}
+
+static void HandleDefinition() {
+  if (auto FnAST = ParseDefinition()) {
+    if (!FnAST->codegen())
+      fprintf(stderr, "Error reading function definition:");
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+static void HandleExtern() {
+  if (auto ProtoAST = ParseExtern()) {
+    if (!ProtoAST->codegen())
+      fprintf(stderr, "Error reading extern");
+    else
+      FunctionProtos[ProtoAST->getName()] = std::move(ProtoAST);
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+static void HandleTopLevelExpression() {
+  // Evaluate a top-level expression into an anonymous function.
+  if (auto FnAST = ParseTopLevelExpr()) {
+    if (!FnAST->codegen()) {
+      fprintf(stderr, "Error generating code for top level expr");
+    }
+  } else {
+    // Skip token for error recovery.
+    getNextToken();
+  }
+}
+
+/// top ::= definition | external | expression | ';'
+static void MainLoop() {
+  while (1) {
+    switch (CurTok) {
+    case tok_eof:
+      return;
+    case ';': // ignore top-level semicolons.
+      getNextToken();
+      break;
+    case tok_def:
+      HandleDefinition();
+      break;
+    case tok_extern:
+      HandleExtern();
+      break;
+    default:
+      HandleTopLevelExpression();
+      break;
+    }
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// "Library" functions that can be "extern'd" from user code.
+//===----------------------------------------------------------------------===//
+
+#ifdef _WIN32
+#define DLLEXPORT __declspec(dllexport)
+#else
+#define DLLEXPORT
+#endif
+
+/// putchard - putchar that takes a double and returns 0.
+extern "C" DLLEXPORT double putchard(double X) {
+  fputc((char)X, stderr);
+  return 0;
+}
+
+/// printd - printf that takes a double prints it as "%f\n", returning 0.
+extern "C" DLLEXPORT double printd(double X) {
+  fprintf(stderr, "%f\n", X);
+  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; // highest.
+
+  // Prime the first token.
+  getNextToken();
+
+  TheJIT = std::make_unique<KaleidoscopeJIT>();
+
+  InitializeModule();
+
+  // Add the current debug info version into the module.
+  TheModule->addModuleFlag(Module::Warning, "Debug Info Version",
+                           DEBUG_METADATA_VERSION);
+
+  // Darwin only supports dwarf2.
+  if (Triple(sys::getProcessTriple()).isOSDarwin())
+    TheModule->addModuleFlag(llvm::Module::Warning, "Dwarf Version", 2);
+
+  // Construct the DIBuilder, we do this here because we need the module.
+  DBuilder = std::make_unique<DIBuilder>(*TheModule);
+
+  // Create the compile unit for the module.
+  // Currently down as "fib.ks" as a filename since we're redirecting stdin
+  // but we'd like actual source locations.
+  KSDbgInfo.TheCU = DBuilder->createCompileUnit(
+      dwarf::DW_LANG_C, DBuilder->createFile("fib.ks", "."),
+      "Kaleidoscope Compiler", 0, "", 0);
+
+  // Run the main "interpreter loop" now.
+  MainLoop();
+
+  // Finalize the debug info.
+  DBuilder->finalize();
+
+  // Print out all of the generated code.
+  TheModule->print(errs(), nullptr);
+
+  return 0;
+}
-- 
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