Fixed previous commit

Also allows multiple things to be added together

Main.cpp

@@ -53,16 +53,12 @@ int main(int argc, char** argv)
 		// Create tokens out of the input file
 		std::vector<LX::Token>tokens = LX::LexicalAnalyze(inpFile, log.get());
 
-		// Saves the log //
-		if (log != nullptr)
-		{
-			log->close();
-			//log->open(argv[3]);
-		}
-
 		// Turns the tokens into an AST
 		LX::FileAST AST = LX::TurnTokensIntoAbstractSyntaxTree(tokens, log.get());
 
+		//
+		LX::GenerateIR(AST);
+
 		// Returns success
 		return 0;
 	}

Parser/Parser.vcxproj

@@ -132,6 +132,8 @@
   </ItemDefinitionGroup>
   <ItemGroup>
     <ClCompile Include="src\AST-Constructors.cpp" />
+    <ClCompile Include="src\AST-LLVM.cpp" />
+    <ClCompile Include="src\GenIR.cpp" />
     <ClCompile Include="src\Parser.cpp" />
   </ItemGroup>
   <ItemGroup>

Parser/Parser.vcxproj.filters

@@ -17,6 +17,12 @@
     <ClCompile Include="src\AST-Constructors.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="src\AST-LLVM.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="src\GenIR.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="inc\AST.h">

Parser/src/Parser.cpp

@@ -37,12 +37,13 @@ namespace LX
 			// Number literals just require them to be turned into an AST node //
 			// Note: Number literals are stored as strings because i'm a masochist //
 			case Token::NUMBER_LITERAL:
-				return std::make_unique<AST::NumberLiteral>(p.tokens[p.index].contents);
+				return std::make_unique<AST::NumberLiteral>(p.tokens[p.index++].contents);
 
 			// Default just alerts the user of an error //
 			// TODO: Actually make this error tell the user something useful //
 			default:
 				std::cout << "UNKNOWN TOKEN: " << p.tokens[p.index].type << std::endl;
+				p.index++;
 				return nullptr;
 		}
 	}
@@ -53,21 +54,23 @@ namespace LX
 		// Checks if the next token is an operator //
 		// TODO: Add more than just add //
 		// TODO: Make this not crash when at the end //
-		if (p.tokens[p.index + 1].type == Token::ADD)
+		if (p.index + 1 < p.len) [[likely]]
 		{
-			// Parses the left hand side of the operation //
+			if (p.tokens[p.index + 1].type == Token::ADD)
-			std::unique_ptr<AST::Node> lhs = ParsePrimary(p);
+			{
-			p.index++;
+				// Parses the left hand side of the operation //
+				std::unique_ptr<AST::Node> lhs = ParsePrimary(p);
 
-			// Stores the operator to pass into the AST node //
+				// Stores the operator to pass into the AST node //
-			Token::TokenType op = p.tokens[p.index].type;
+				Token::TokenType op = p.tokens[p.index].type;
-			p.index++;
+				p.index++;
 
-			// Parses the right hand of the operation //
+				// Parses the right hand of the operation //
-			std::unique_ptr<AST::Node> rhs = ParsePrimary(p);
+				std::unique_ptr<AST::Node> rhs = ParseOperation(p);
 
-			// Returns an AST node as all of the components combined together //
+				// Returns an AST node as all of the components combined together //
-			return std::make_unique<AST::Operation>(std::move(lhs), op, std::move(rhs));
+				return std::make_unique<AST::Operation>(std::move(lhs), op, std::move(rhs));
+			}
 		}
 
 		// Else goes down the call stack //
@@ -130,9 +133,8 @@ namespace LX
 						// Actually parses the function
 						std::unique_ptr<AST::Node> node = Parse(p);
 
-						// Adds it to the vector and iterates to the next token
+						// Adds it to the vector
 						func.body.push_back(std::move(node));
-						p.index++;
 					}
 
 					// Goes to the next iteration of the loop //

build-test/Log.txt

@@ -6,6 +6,24 @@ Started lexing file
 Token::FUNCTION
 Token::IDENTIFIER:	main
 Unknown: 3
+Token::NUMBER_LITERAL:	1
+Token::ADD
+Token::NUMBER_LITERAL:	2
+Token::ADD
 Token::NUMBER_LITERAL:	3
 Token::ADD
-Token::NUMBER_LITERAL:	56
+Token::NUMBER_LITERAL:	4
+Token::ADD
+Token::NUMBER_LITERAL:	5
+Token::ADD
+Token::NUMBER_LITERAL:	6
+Token::ADD
+Token::NUMBER_LITERAL:	7
+Token::ADD
+Token::NUMBER_LITERAL:	8
+
+-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+Started parsing tokens
+-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+
+AST length: 1

build-test/main.lx

@@ -1,2 +1,2 @@
 func main
-    return 3 + 56
+    return 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8

build-test/tmp

@@ -1,261 +0,0 @@
-/* File 0 */
-
-namespace LX::AST
-{
-	// Base node that everything else inherits from
-	struct Node
-	{
-		// Enum for storing the type of node //
-		// Used so a pointer to Node can be used and then turned into it's true type //
-		enum NodeType
-		{
-			// General Nodes //
-
-			IDENTIFIER,
-			NUMBER_LITERAL,
-			OPERATION,
-
-			// Control flow Nodes //
-
-			RETURN_STATEMENT,
-
-			// If an error happened somewhere //
-			UNDEFINED = -1
-		};
-
-		// Constructor to set the node type //
-		Node(NodeType type)
-			: m_Type(type)
-		{}
-
-		// Virtual destructor because of polymorphism //
-		virtual ~Node() = default;
-
-		// Function for generating LLVN IR (Intermediate representation) //
-		virtual llvm::Value* GenIR(llvm::LLVMContext& context, llvm::Module& module, llvm::IRBuilder<>& builder) = 0;
-
-		// Function for generating C/C++ code (Currently not implemented) //
-		//virtual void GenC() = 0;
-
-		// The type of the node //
-		const NodeType m_Type;
-	};
-
-	class NumberLiteral : public Node
-	{
-		public:
-			// Constructor to set values and automatically set type
-			NumberLiteral(std::string num);
-
-			// Function for generating LLVN IR (Intermediate representation) //
-			llvm::Value* GenIR(llvm::LLVMContext& context, llvm::Module& module, llvm::IRBuilder<>& builder) override;
-
-		private:
-			// The number it stores
-			// Yes the number is stored as a string
-			// It's horrible I know
-			std::string m_Number;
-	};
-
-	//
-	class Operation : public Node
-	{
-		public:
-			// Constructor to set values and automatically set type
-			Operation(std::unique_ptr<Node> lhs, Token::TokenType op, std::unique_ptr<Node> rhs);
-
-			// Function for generating LLVN IR (Intermediate representation) //
-			llvm::Value* GenIR(llvm::LLVMContext& context, llvm::Module& module, llvm::IRBuilder<>& builder) override;
-
-		private:
-			// The sides of the operation
-			// Unary operations are handled by a different class
-			std::unique_ptr<Node> m_Lhs, m_Rhs;
-
-			// The operation to be applied to the two sides
-			Token::TokenType m_Operand;
-	};
-
-	//
-	class ReturnStatement : public Node
-	{
-		public:
-			// Constructor to set values and automatically set type
-			ReturnStatement(std::unique_ptr<Node> val);
-
-			// Function for generating LLVN IR (Intermediate representation) //
-			llvm::Value* GenIR(llvm::LLVMContext& context, llvm::Module& module, llvm::IRBuilder<>& builder) override;
-
-		private:
-			// What it is returning (can be null)
-			std::unique_ptr<Node> m_Val;
-	};
-}
-
-namespace LX
-{
-	struct IRGenerationError {};
-
-	struct FunctionDefinition
-	{
-		FunctionDefinition()
-			: body{}
-		{}
-		
-		std::vector<std::unique_ptr<AST::Node>> body;
-	};
-
-	struct FileAST
-	{
-		FileAST()
-			: functions{}
-		{}
-
-		std::vector<FunctionDefinition> functions;
-	};
-
-	FileAST TurnTokensIntoAbstractSyntaxTree(std::vector<Token>& tokens, std::ofstream* log);
-
-	void GenerateIR(FileAST& ast);
-}
-
-/* File 1 */
-
-#include <Parser.h>
-
-#include <LLVM.h>
-#include <Util.h>
-
-namespace LX::AST
-{
-	llvm::Value* NumberLiteral::GenIR(llvm::LLVMContext& context, llvm::Module& module, llvm::IRBuilder<>& builder)
-	{
-		// Converts the string to it's int equivalent
-		// Will eventually need to do floating point stuff here as well
-		int number = std::stoi(m_Number);
-
-		// Returns it as a llvm value (if valid)
-		llvm::Value* out = llvm::ConstantInt::get(llvm::Type::getInt32Ty(context), number, true);
-		ThrowIf<IRGenerationError>(out == nullptr);
-		return out;
-	}
-
-	llvm::Value* Operation::GenIR(llvm::LLVMContext& context, llvm::Module& module, llvm::IRBuilder<>& builder)
-	{
-		// Gets the IR for both sides of the operation
-		llvm::Value* lhs = m_Lhs->GenIR(context, module, builder);
-		llvm::Value* rhs = m_Rhs->GenIR(context, module, builder);
-
-		// If either side is null then return null to prevent invalid IR //
-		if (lhs == nullptr || rhs == nullptr)
-		{
-			ThrowIf<IRGenerationError>(true);
-			return nullptr;
-		}
-
-		// Will eventually get the correct operator but for now everything is add
-		llvm::Value* out = builder.CreateAdd(lhs, rhs);
-		ThrowIf<IRGenerationError>(out == nullptr);
-		return out;
-	}
-
-	llvm::Value* ReturnStatement::GenIR(llvm::LLVMContext& context, llvm::Module& module, llvm::IRBuilder<>& builder)
-	{
-		if (m_Val == nullptr)
-		{
-			ThrowIf<IRGenerationError>(true);
-			return nullptr;
-		}
-
-		else
-		{
-			llvm::Value* out = builder.CreateRet(m_Val->GenIR(context, module, builder));
-			ThrowIf<IRGenerationError>(out == nullptr);
-			return out;
-		}
-	}
-}
-
-/* File 2 */
-
-#include <Parser.h>
-
-#include <iostream>
-
-namespace LX
-{
-	void GenerateIR(FileAST& ast)
-	{
-		// Generates stuff //
-
-		llvm::LLVMContext context;
-		llvm::IRBuilder<> builder(context);
-		
-		{
-			std::unique_ptr<llvm::Module> module = std::make_unique<llvm::Module>("add_ints", context);
-
-			// Defines main function //
-
-			llvm::FunctionType* funcType = llvm::FunctionType::get(llvm::Type::getInt32Ty(context), false);
-			llvm::Function* mainFunc = llvm::Function::Create(funcType, llvm::Function::ExternalLinkage, "main", module.get());
-			llvm::BasicBlock* entry = llvm::BasicBlock::Create(context, "entry", mainFunc);
-			builder.SetInsertPoint(entry);
-
-			// Loops over AST to generate IR //
-
-			for (auto& node : ast.functions[0].body)
-			{
-				switch (node->m_Type)
-				{
-					case AST::Node::RETURN_STATEMENT:
-					{
-						node->GenIR(context, *module, builder);
-						break;
-					}
-
-					default:
-					{
-						break;
-					}
-				}
-			}
-
-			if (entry->getTerminator() == nullptr)
-			{
-				builder.CreateRet(llvm::ConstantInt::get(llvm::Type::getInt32Ty(context), 0, true));
-			}
-
-			// Verification of the IR //
-
-			if (llvm::verifyFunction(*mainFunc, &llvm::errs()) || llvm::verifyModule(*module, &llvm::errs()))
-			{
-				std::cerr << "Error: IR generation failed" << std::endl;
-				return;
-			}
-
-			// Outputs the IR to the console //
-
-			module->print(llvm::outs(), nullptr);
-
-		} // <- Crashes here
-
-		std::cout << "Finished generating IR" << std::endl;
-	}
-}
-
-
-/* Output */
-
-; ModuleID = 'add_ints'
-source_filename = "add_ints"
-
-define i32 @main() {
-entry:
-  ret i32 7
-}
-Finished generating IR
-
-/* AST */
-
-func main
-    return 3 + 4

build-test/x.cpp

@@ -1,622 +0,0 @@
-#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 std::unique_ptr<LLVMContext> TheContext;
-static std::unique_ptr<Module> TheModule;
-static std::unique_ptr<IRBuilder<>> Builder;
-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 InitializeModule() {
-  // Open a new context and module.
-  TheContext = std::make_unique<LLVMContext>();
-  TheModule = std::make_unique<Module>("my cool jit", *TheContext);
-
-  // Create a new builder for the module.
-  Builder = std::make_unique<IRBuilder<>>(*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");
-    }
-  } 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");
-
-      // Remove the anonymous expression.
-      FnIR->eraseFromParent();
-    }
-  } 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.
-  InitializeModule();
-
-  // Run the main "interpreter loop" now.
-  MainLoop();
-
-  // Print out all of the generated code.
-  TheModule->print(errs(), nullptr);
-
-  return 0;
-}