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1#define MINIMAL_STDERR_OUTPUT2 3#include "llvm/Analysis/Passes.h"4#include "llvm/ExecutionEngine/ExecutionEngine.h"5#include "llvm/ExecutionEngine/MCJIT.h"6#include "llvm/ExecutionEngine/ObjectCache.h"7#include "llvm/ExecutionEngine/SectionMemoryManager.h"8#include "llvm/IR/DataLayout.h"9#include "llvm/IR/DerivedTypes.h"10#include "llvm/IR/IRBuilder.h"11#include "llvm/IR/LLVMContext.h"12#include "llvm/IR/LegacyPassManager.h"13#include "llvm/IR/Module.h"14#include "llvm/IR/Verifier.h"15#include "llvm/IRReader/IRReader.h"16#include "llvm/Support/CommandLine.h"17#include "llvm/Support/FileSystem.h"18#include "llvm/Support/Path.h"19#include "llvm/Support/SourceMgr.h"20#include "llvm/Support/TargetSelect.h"21#include "llvm/Support/raw_ostream.h"22#include "llvm/Transforms/Scalar.h"23#include <cctype>24#include <cstdio>25#include <map>26#include <string>27#include <vector>28using namespace llvm;29 30//===----------------------------------------------------------------------===//31// Command-line options32//===----------------------------------------------------------------------===//33 34static cl::opt<std::string> InputIR(35    "input-IR",36    cl::desc("Specify the name of an IR file to load for function definitions"),37    cl::value_desc("input IR file name"));38 39static cl::opt<bool>40    UseObjectCache("use-object-cache",41                   cl::desc("Enable use of the MCJIT object caching"),42                   cl::init(false));43 44//===----------------------------------------------------------------------===//45// Lexer46//===----------------------------------------------------------------------===//47 48// The lexer returns tokens [0-255] if it is an unknown character, otherwise one49// of these for known things.50enum Token {51  tok_eof = -1,52 53  // commands54  tok_def = -2, tok_extern = -3,55 56  // primary57  tok_identifier = -4, tok_number = -5,58 59  // control60  tok_if = -6, tok_then = -7, tok_else = -8,61  tok_for = -9, tok_in = -10,62 63  // operators64  tok_binary = -11, tok_unary = -12,65 66  // var definition67  tok_var = -1368};69 70static std::string IdentifierStr;  // Filled in if tok_identifier71static double NumVal;              // Filled in if tok_number72 73/// gettok - Return the next token from standard input.74static int gettok() {75  static int LastChar = ' ';76 77  // Skip any whitespace.78  while (isspace(LastChar))79    LastChar = getchar();80 81  if (isalpha(LastChar)) { // identifier: [a-zA-Z][a-zA-Z0-9]*82    IdentifierStr = LastChar;83    while (isalnum((LastChar = getchar())))84      IdentifierStr += LastChar;85 86    if (IdentifierStr == "def") return tok_def;87    if (IdentifierStr == "extern") return tok_extern;88    if (IdentifierStr == "if") return tok_if;89    if (IdentifierStr == "then") return tok_then;90    if (IdentifierStr == "else") return tok_else;91    if (IdentifierStr == "for") return tok_for;92    if (IdentifierStr == "in") return tok_in;93    if (IdentifierStr == "binary") return tok_binary;94    if (IdentifierStr == "unary") return tok_unary;95    if (IdentifierStr == "var") return tok_var;96    return tok_identifier;97  }98 99  if (isdigit(LastChar) || LastChar == '.') {   // Number: [0-9.]+100    std::string NumStr;101    do {102      NumStr += LastChar;103      LastChar = getchar();104    } while (isdigit(LastChar) || LastChar == '.');105 106    NumVal = strtod(NumStr.c_str(), 0);107    return tok_number;108  }109 110  if (LastChar == '#') {111    // Comment until end of line.112    do LastChar = getchar();113    while (LastChar != EOF && LastChar != '\n' && LastChar != '\r');114 115    if (LastChar != EOF)116      return gettok();117  }118 119  // Check for end of file.  Don't eat the EOF.120  if (LastChar == EOF)121    return tok_eof;122 123  // Otherwise, just return the character as its ascii value.124  int ThisChar = LastChar;125  LastChar = getchar();126  return ThisChar;127}128 129//===----------------------------------------------------------------------===//130// Abstract Syntax Tree (aka Parse Tree)131//===----------------------------------------------------------------------===//132 133/// ExprAST - Base class for all expression nodes.134class ExprAST {135public:136  virtual ~ExprAST() {}137  virtual Value *Codegen() = 0;138};139 140/// NumberExprAST - Expression class for numeric literals like "1.0".141class NumberExprAST : public ExprAST {142  double Val;143public:144  NumberExprAST(double val) : Val(val) {}145  virtual Value *Codegen();146};147 148/// VariableExprAST - Expression class for referencing a variable, like "a".149class VariableExprAST : public ExprAST {150  std::string Name;151public:152  VariableExprAST(const std::string &name) : Name(name) {}153  const std::string &getName() const { return Name; }154  virtual Value *Codegen();155};156 157/// UnaryExprAST - Expression class for a unary operator.158class UnaryExprAST : public ExprAST {159  char Opcode;160  ExprAST *Operand;161public:162  UnaryExprAST(char opcode, ExprAST *operand)163    : Opcode(opcode), Operand(operand) {}164  virtual Value *Codegen();165};166 167/// BinaryExprAST - Expression class for a binary operator.168class BinaryExprAST : public ExprAST {169  char Op;170  ExprAST *LHS, *RHS;171public:172  BinaryExprAST(char op, ExprAST *lhs, ExprAST *rhs)173    : Op(op), LHS(lhs), RHS(rhs) {}174  virtual Value *Codegen();175};176 177/// CallExprAST - Expression class for function calls.178class CallExprAST : public ExprAST {179  std::string Callee;180  std::vector<ExprAST*> Args;181public:182  CallExprAST(const std::string &callee, std::vector<ExprAST*> &args)183    : Callee(callee), Args(args) {}184  virtual Value *Codegen();185};186 187/// IfExprAST - Expression class for if/then/else.188class IfExprAST : public ExprAST {189  ExprAST *Cond, *Then, *Else;190public:191  IfExprAST(ExprAST *cond, ExprAST *then, ExprAST *_else)192  : Cond(cond), Then(then), Else(_else) {}193  virtual Value *Codegen();194};195 196/// ForExprAST - Expression class for for/in.197class ForExprAST : public ExprAST {198  std::string VarName;199  ExprAST *Start, *End, *Step, *Body;200public:201  ForExprAST(const std::string &varname, ExprAST *start, ExprAST *end,202             ExprAST *step, ExprAST *body)203    : VarName(varname), Start(start), End(end), Step(step), Body(body) {}204  virtual Value *Codegen();205};206 207/// VarExprAST - Expression class for var/in208class VarExprAST : public ExprAST {209  std::vector<std::pair<std::string, ExprAST*> > VarNames;210  ExprAST *Body;211public:212  VarExprAST(const std::vector<std::pair<std::string, ExprAST*> > &varnames,213             ExprAST *body)214  : VarNames(varnames), Body(body) {}215 216  virtual Value *Codegen();217};218 219/// PrototypeAST - This class represents the "prototype" for a function,220/// which captures its argument names as well as if it is an operator.221class PrototypeAST {222  std::string Name;223  std::vector<std::string> Args;224  bool isOperator;225  unsigned Precedence;  // Precedence if a binary op.226public:227  PrototypeAST(const std::string &name, const std::vector<std::string> &args,228               bool isoperator = false, unsigned prec = 0)229  : Name(name), Args(args), isOperator(isoperator), Precedence(prec) {}230 231  bool isUnaryOp() const { return isOperator && Args.size() == 1; }232  bool isBinaryOp() const { return isOperator && Args.size() == 2; }233 234  char getOperatorName() const {235    assert(isUnaryOp() || isBinaryOp());236    return Name[Name.size()-1];237  }238 239  unsigned getBinaryPrecedence() const { return Precedence; }240 241  Function *Codegen();242 243  void CreateArgumentAllocas(Function *F);244};245 246/// FunctionAST - This class represents a function definition itself.247class FunctionAST {248  PrototypeAST *Proto;249  ExprAST *Body;250public:251  FunctionAST(PrototypeAST *proto, ExprAST *body)252    : Proto(proto), Body(body) {}253 254  Function *Codegen();255};256 257//===----------------------------------------------------------------------===//258// Parser259//===----------------------------------------------------------------------===//260 261/// CurTok/getNextToken - Provide a simple token buffer.  CurTok is the current262/// token the parser is looking at.  getNextToken reads another token from the263/// lexer and updates CurTok with its results.264static int CurTok;265static int getNextToken() {266  return CurTok = gettok();267}268 269/// BinopPrecedence - This holds the precedence for each binary operator that is270/// defined.271static std::map<char, int> BinopPrecedence;272 273/// GetTokPrecedence - Get the precedence of the pending binary operator token.274static int GetTokPrecedence() {275  if (!isascii(CurTok))276    return -1;277 278  // Make sure it's a declared binop.279  int TokPrec = BinopPrecedence[CurTok];280  if (TokPrec <= 0) return -1;281  return TokPrec;282}283 284/// Error* - These are little helper functions for error handling.285ExprAST *Error(const char *Str) { fprintf(stderr, "Error: %s\n", Str);return 0;}286PrototypeAST *ErrorP(const char *Str) { Error(Str); return 0; }287FunctionAST *ErrorF(const char *Str) { Error(Str); return 0; }288 289static ExprAST *ParseExpression();290 291/// identifierexpr292///   ::= identifier293///   ::= identifier '(' expression* ')'294static ExprAST *ParseIdentifierExpr() {295  std::string IdName = IdentifierStr;296 297  getNextToken();  // eat identifier.298 299  if (CurTok != '(') // Simple variable ref.300    return new VariableExprAST(IdName);301 302  // Call.303  getNextToken();  // eat (304  std::vector<ExprAST*> Args;305  if (CurTok != ')') {306    while (1) {307      ExprAST *Arg = ParseExpression();308      if (!Arg) return 0;309      Args.push_back(Arg);310 311      if (CurTok == ')') break;312 313      if (CurTok != ',')314        return Error("Expected ')' or ',' in argument list");315      getNextToken();316    }317  }318 319  // Eat the ')'.320  getNextToken();321 322  return new CallExprAST(IdName, Args);323}324 325/// numberexpr ::= number326static ExprAST *ParseNumberExpr() {327  ExprAST *Result = new NumberExprAST(NumVal);328  getNextToken(); // consume the number329  return Result;330}331 332/// parenexpr ::= '(' expression ')'333static ExprAST *ParseParenExpr() {334  getNextToken();  // eat (.335  ExprAST *V = ParseExpression();336  if (!V) return 0;337 338  if (CurTok != ')')339    return Error("expected ')'");340  getNextToken();  // eat ).341  return V;342}343 344/// ifexpr ::= 'if' expression 'then' expression 'else' expression345static ExprAST *ParseIfExpr() {346  getNextToken();  // eat the if.347 348  // condition.349  ExprAST *Cond = ParseExpression();350  if (!Cond) return 0;351 352  if (CurTok != tok_then)353    return Error("expected then");354  getNextToken();  // eat the then355 356  ExprAST *Then = ParseExpression();357  if (Then == 0) return 0;358 359  if (CurTok != tok_else)360    return Error("expected else");361 362  getNextToken();363 364  ExprAST *Else = ParseExpression();365  if (!Else) return 0;366 367  return new IfExprAST(Cond, Then, Else);368}369 370/// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression371static ExprAST *ParseForExpr() {372  getNextToken();  // eat the for.373 374  if (CurTok != tok_identifier)375    return Error("expected identifier after for");376 377  std::string IdName = IdentifierStr;378  getNextToken();  // eat identifier.379 380  if (CurTok != '=')381    return Error("expected '=' after for");382  getNextToken();  // eat '='.383 384 385  ExprAST *Start = ParseExpression();386  if (Start == 0) return 0;387  if (CurTok != ',')388    return Error("expected ',' after for start value");389  getNextToken();390 391  ExprAST *End = ParseExpression();392  if (End == 0) return 0;393 394  // The step value is optional.395  ExprAST *Step = 0;396  if (CurTok == ',') {397    getNextToken();398    Step = ParseExpression();399    if (Step == 0) return 0;400  }401 402  if (CurTok != tok_in)403    return Error("expected 'in' after for");404  getNextToken();  // eat 'in'.405 406  ExprAST *Body = ParseExpression();407  if (Body == 0) return 0;408 409  return new ForExprAST(IdName, Start, End, Step, Body);410}411 412/// varexpr ::= 'var' identifier ('=' expression)?413//                    (',' identifier ('=' expression)?)* 'in' expression414static ExprAST *ParseVarExpr() {415  getNextToken();  // eat the var.416 417  std::vector<std::pair<std::string, ExprAST*> > VarNames;418 419  // At least one variable name is required.420  if (CurTok != tok_identifier)421    return Error("expected identifier after var");422 423  while (1) {424    std::string Name = IdentifierStr;425    getNextToken();  // eat identifier.426 427    // Read the optional initializer.428    ExprAST *Init = 0;429    if (CurTok == '=') {430      getNextToken(); // eat the '='.431 432      Init = ParseExpression();433      if (Init == 0) return 0;434    }435 436    VarNames.push_back(std::make_pair(Name, Init));437 438    // End of var list, exit loop.439    if (CurTok != ',') break;440    getNextToken(); // eat the ','.441 442    if (CurTok != tok_identifier)443      return Error("expected identifier list after var");444  }445 446  // At this point, we have to have 'in'.447  if (CurTok != tok_in)448    return Error("expected 'in' keyword after 'var'");449  getNextToken();  // eat 'in'.450 451  ExprAST *Body = ParseExpression();452  if (Body == 0) return 0;453 454  return new VarExprAST(VarNames, Body);455}456 457/// primary458///   ::= identifierexpr459///   ::= numberexpr460///   ::= parenexpr461///   ::= ifexpr462///   ::= forexpr463///   ::= varexpr464static ExprAST *ParsePrimary() {465  switch (CurTok) {466  default: return Error("unknown token when expecting an expression");467  case tok_identifier: return ParseIdentifierExpr();468  case tok_number:     return ParseNumberExpr();469  case '(':            return ParseParenExpr();470  case tok_if:         return ParseIfExpr();471  case tok_for:        return ParseForExpr();472  case tok_var:        return ParseVarExpr();473  }474}475 476/// unary477///   ::= primary478///   ::= '!' unary479static ExprAST *ParseUnary() {480  // If the current token is not an operator, it must be a primary expr.481  if (!isascii(CurTok) || CurTok == '(' || CurTok == ',')482    return ParsePrimary();483 484  // If this is a unary operator, read it.485  int Opc = CurTok;486  getNextToken();487  if (ExprAST *Operand = ParseUnary())488    return new UnaryExprAST(Opc, Operand);489  return 0;490}491 492/// binoprhs493///   ::= ('+' unary)*494static ExprAST *ParseBinOpRHS(int ExprPrec, ExprAST *LHS) {495  // If this is a binop, find its precedence.496  while (1) {497    int TokPrec = GetTokPrecedence();498 499    // If this is a binop that binds at least as tightly as the current binop,500    // consume it, otherwise we are done.501    if (TokPrec < ExprPrec)502      return LHS;503 504    // Okay, we know this is a binop.505    int BinOp = CurTok;506    getNextToken();  // eat binop507 508    // Parse the unary expression after the binary operator.509    ExprAST *RHS = ParseUnary();510    if (!RHS) return 0;511 512    // If BinOp binds less tightly with RHS than the operator after RHS, let513    // the pending operator take RHS as its LHS.514    int NextPrec = GetTokPrecedence();515    if (TokPrec < NextPrec) {516      RHS = ParseBinOpRHS(TokPrec+1, RHS);517      if (RHS == 0) return 0;518    }519 520    // Merge LHS/RHS.521    LHS = new BinaryExprAST(BinOp, LHS, RHS);522  }523}524 525/// expression526///   ::= unary binoprhs527///528static ExprAST *ParseExpression() {529  ExprAST *LHS = ParseUnary();530  if (!LHS) return 0;531 532  return ParseBinOpRHS(0, LHS);533}534 535/// prototype536///   ::= id '(' id* ')'537///   ::= binary LETTER number? (id, id)538///   ::= unary LETTER (id)539static PrototypeAST *ParsePrototype() {540  std::string FnName;541 542  unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.543  unsigned BinaryPrecedence = 30;544 545  switch (CurTok) {546  default:547    return ErrorP("Expected function name in prototype");548  case tok_identifier:549    FnName = IdentifierStr;550    Kind = 0;551    getNextToken();552    break;553  case tok_unary:554    getNextToken();555    if (!isascii(CurTok))556      return ErrorP("Expected unary operator");557    FnName = "unary";558    FnName += (char)CurTok;559    Kind = 1;560    getNextToken();561    break;562  case tok_binary:563    getNextToken();564    if (!isascii(CurTok))565      return ErrorP("Expected binary operator");566    FnName = "binary";567    FnName += (char)CurTok;568    Kind = 2;569    getNextToken();570 571    // Read the precedence if present.572    if (CurTok == tok_number) {573      if (NumVal < 1 || NumVal > 100)574        return ErrorP("Invalid precedence: must be 1..100");575      BinaryPrecedence = (unsigned)NumVal;576      getNextToken();577    }578    break;579  }580 581  if (CurTok != '(')582    return ErrorP("Expected '(' in prototype");583 584  std::vector<std::string> ArgNames;585  while (getNextToken() == tok_identifier)586    ArgNames.push_back(IdentifierStr);587  if (CurTok != ')')588    return ErrorP("Expected ')' in prototype");589 590  // success.591  getNextToken();  // eat ')'.592 593  // Verify right number of names for operator.594  if (Kind && ArgNames.size() != Kind)595    return ErrorP("Invalid number of operands for operator");596 597  return new PrototypeAST(FnName, ArgNames, Kind != 0, BinaryPrecedence);598}599 600/// definition ::= 'def' prototype expression601static FunctionAST *ParseDefinition() {602  getNextToken();  // eat def.603  PrototypeAST *Proto = ParsePrototype();604  if (Proto == 0) return 0;605 606  if (ExprAST *E = ParseExpression())607    return new FunctionAST(Proto, E);608  return 0;609}610 611/// toplevelexpr ::= expression612static FunctionAST *ParseTopLevelExpr() {613  if (ExprAST *E = ParseExpression()) {614    // Make an anonymous proto.615    PrototypeAST *Proto = new PrototypeAST("", std::vector<std::string>());616    return new FunctionAST(Proto, E);617  }618  return 0;619}620 621/// external ::= 'extern' prototype622static PrototypeAST *ParseExtern() {623  getNextToken();  // eat extern.624  return ParsePrototype();625}626 627//===----------------------------------------------------------------------===//628// Quick and dirty hack629//===----------------------------------------------------------------------===//630 631// FIXME: Obviously we can do better than this632std::string GenerateUniqueName(const char *root)633{634  static int i = 0;635  char s[16];636  sprintf(s, "%s%d", root, i++);637  std::string S = s;638  return S;639}640 641std::string MakeLegalFunctionName(std::string Name)642{643  std::string NewName;644  if (!Name.length())645      return GenerateUniqueName("anon_func_");646 647  // Start with what we have648  NewName = Name;649 650  // Look for a numeric first character651  if (NewName.find_first_of("0123456789") == 0) {652    NewName.insert(0, 1, 'n');653  }654 655  // Replace illegal characters with their ASCII equivalent656  std::string legal_elements = "_abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";657  size_t pos;658  while ((pos = NewName.find_first_not_of(legal_elements)) != std::string::npos) {659    char old_c = NewName.at(pos);660    char new_str[16];661    sprintf(new_str, "%d", (int)old_c);662    NewName = NewName.replace(pos, 1, new_str);663  }664 665  return NewName;666}667 668//===----------------------------------------------------------------------===//669// MCJIT object cache class670//===----------------------------------------------------------------------===//671 672class MCJITObjectCache : public ObjectCache {673public:674  MCJITObjectCache() {675    // Set IR cache directory676    sys::fs::current_path(CacheDir);677    sys::path::append(CacheDir, "toy_object_cache");678  }679 680  virtual ~MCJITObjectCache() {681  }682 683  virtual void notifyObjectCompiled(const Module *M, const MemoryBuffer *Obj) {684    // Get the ModuleID685    const std::string ModuleID = M->getModuleIdentifier();686 687    // If we've flagged this as an IR file, cache it688    if (0 == ModuleID.compare(0, 3, "IR:")) {689      std::string IRFileName = ModuleID.substr(3);690      SmallString<128>IRCacheFile = CacheDir;691      sys::path::append(IRCacheFile, IRFileName);692      if (!sys::fs::exists(CacheDir.str()) && sys::fs::create_directory(CacheDir.str())) {693        fprintf(stderr, "Unable to create cache directory\n");694        return;695      }696      std::string ErrStr;697      raw_fd_ostream IRObjectFile(IRCacheFile.c_str(), ErrStr, raw_fd_ostream::F_Binary);698      IRObjectFile << Obj->getBuffer();699    }700  }701 702  // MCJIT will call this function before compiling any module703  // MCJIT takes ownership of both the MemoryBuffer object and the memory704  // to which it refers.705  virtual MemoryBuffer* getObject(const Module* M) {706    // Get the ModuleID707    const std::string ModuleID = M->getModuleIdentifier();708 709    // If we've flagged this as an IR file, cache it710    if (0 == ModuleID.compare(0, 3, "IR:")) {711      std::string IRFileName = ModuleID.substr(3);712      SmallString<128> IRCacheFile = CacheDir;713      sys::path::append(IRCacheFile, IRFileName);714      if (!sys::fs::exists(IRCacheFile.str())) {715        // This file isn't in our cache716        return NULL;717      }718      std::unique_ptr<MemoryBuffer> IRObjectBuffer;719      MemoryBuffer::getFile(IRCacheFile.c_str(), IRObjectBuffer, -1, false);720      // MCJIT will want to write into this buffer, and we don't want that721      // because the file has probably just been mmapped.  Instead we make722      // a copy.  The filed-based buffer will be released when it goes723      // out of scope.724      return MemoryBuffer::getMemBufferCopy(IRObjectBuffer->getBuffer());725    }726 727    return NULL;728  }729 730private:731  SmallString<128> CacheDir;732};733 734//===----------------------------------------------------------------------===//735// MCJIT helper class736//===----------------------------------------------------------------------===//737 738class MCJITHelper739{740public:741  MCJITHelper(LLVMContext& C) : Context(C), OpenModule(NULL) {}742  ~MCJITHelper();743 744  Function *getFunction(const std::string FnName);745  Module *getModuleForNewFunction();746  void *getPointerToFunction(Function* F);747  void *getPointerToNamedFunction(const std::string &Name);748  ExecutionEngine *compileModule(Module *M);749  void closeCurrentModule();750  void addModule(Module *M);751  void dump();752 753private:754  typedef std::vector<Module*> ModuleVector;755 756  LLVMContext  &Context;757  Module       *OpenModule;758  ModuleVector  Modules;759  std::map<Module *, ExecutionEngine *> EngineMap;760  MCJITObjectCache OurObjectCache;761};762 763class HelpingMemoryManager : public SectionMemoryManager764{765  HelpingMemoryManager(const HelpingMemoryManager&) = delete;766  void operator=(const HelpingMemoryManager&) = delete;767 768public:769  HelpingMemoryManager(MCJITHelper *Helper) : MasterHelper(Helper) {}770  virtual ~HelpingMemoryManager() {}771 772  /// This method returns the address of the specified function.773  /// Our implementation will attempt to find functions in other774  /// modules associated with the MCJITHelper to cross link functions775  /// from one generated module to another.776  ///777  /// If \p AbortOnFailure is false and no function with the given name is778  /// found, this function returns a null pointer. Otherwise, it prints a779  /// message to stderr and aborts.780  virtual void *getPointerToNamedFunction(const std::string &Name,781                                          bool AbortOnFailure = true);782private:783  MCJITHelper *MasterHelper;784};785 786void *HelpingMemoryManager::getPointerToNamedFunction(const std::string &Name,787                                        bool AbortOnFailure)788{789  // Try the standard symbol resolution first, but ask it not to abort.790  void *pfn = SectionMemoryManager::getPointerToNamedFunction(Name, false);791  if (pfn)792    return pfn;793 794  pfn = MasterHelper->getPointerToNamedFunction(Name);795  if (!pfn && AbortOnFailure)796    report_fatal_error("Program used external function '" + Name +797                        "' which could not be resolved!");798  return pfn;799}800 801MCJITHelper::~MCJITHelper()802{803  // Walk the vector of modules.804  ModuleVector::iterator it, end;805  for (it = Modules.begin(), end = Modules.end();806       it != end; ++it) {807    // See if we have an execution engine for this module.808    std::map<Module*, ExecutionEngine*>::iterator mapIt = EngineMap.find(*it);809    // If we have an EE, the EE owns the module so just delete the EE.810    if (mapIt != EngineMap.end()) {811      delete mapIt->second;812    } else {813      // Otherwise, we still own the module.  Delete it now.814      delete *it;815    }816  }817}818 819Function *MCJITHelper::getFunction(const std::string FnName) {820  ModuleVector::iterator begin = Modules.begin();821  ModuleVector::iterator end = Modules.end();822  ModuleVector::iterator it;823  for (it = begin; it != end; ++it) {824    Function *F = (*it)->getFunction(FnName);825    if (F) {826      if (*it == OpenModule)827          return F;828 829      assert(OpenModule != NULL);830 831      // This function is in a module that has already been JITed.832      // We need to generate a new prototype for external linkage.833      Function *PF = OpenModule->getFunction(FnName);834      if (PF && !PF->empty()) {835        ErrorF("redefinition of function across modules");836        return 0;837      }838 839      // If we don't have a prototype yet, create one.840      if (!PF)841        PF = Function::Create(F->getFunctionType(),842                                      Function::ExternalLinkage,843                                      FnName,844                                      OpenModule);845      return PF;846    }847  }848  return NULL;849}850 851Module *MCJITHelper::getModuleForNewFunction() {852  // If we have a Module that hasn't been JITed, use that.853  if (OpenModule)854    return OpenModule;855 856  // Otherwise create a new Module.857  std::string ModName = GenerateUniqueName("mcjit_module_");858  Module *M = new Module(ModName, Context);859  Modules.push_back(M);860  OpenModule = M;861  return M;862}863 864void *MCJITHelper::getPointerToFunction(Function* F) {865  // Look for this function in an existing module866  ModuleVector::iterator begin = Modules.begin();867  ModuleVector::iterator end = Modules.end();868  ModuleVector::iterator it;869  std::string FnName = F->getName();870  for (it = begin; it != end; ++it) {871    Function *MF = (*it)->getFunction(FnName);872    if (MF == F) {873      std::map<Module*, ExecutionEngine*>::iterator eeIt = EngineMap.find(*it);874      if (eeIt != EngineMap.end()) {875        void *P = eeIt->second->getPointerToFunction(F);876        if (P)877          return P;878      } else {879        ExecutionEngine *EE = compileModule(*it);880        void *P = EE->getPointerToFunction(F);881        if (P)882          return P;883      }884    }885  }886  return NULL;887}888 889void MCJITHelper::closeCurrentModule() {890  OpenModule = NULL;891}892 893ExecutionEngine *MCJITHelper::compileModule(Module *M) {894  if (M == OpenModule)895    closeCurrentModule();896 897  std::string ErrStr;898  ExecutionEngine *NewEngine = EngineBuilder(M)899                                            .setErrorStr(&ErrStr)900                                            .setMCJITMemoryManager(new HelpingMemoryManager(this))901                                            .create();902  if (!NewEngine) {903    fprintf(stderr, "Could not create ExecutionEngine: %s\n", ErrStr.c_str());904    exit(1);905  }906 907  if (UseObjectCache)908    NewEngine->setObjectCache(&OurObjectCache);909 910  // Get the ModuleID so we can identify IR input files911  const std::string ModuleID = M->getModuleIdentifier();912 913  // If we've flagged this as an IR file, it doesn't need function passes run.914  if (0 != ModuleID.compare(0, 3, "IR:")) {915    // Create a function pass manager for this engine916    FunctionPassManager *FPM = new FunctionPassManager(M);917 918    // Set up the optimizer pipeline.  Start with registering info about how the919    // target lays out data structures.920    FPM->add(new DataLayout(*NewEngine->getDataLayout()));921    // Provide basic AliasAnalysis support for GVN.922    FPM->add(createBasicAliasAnalysisPass());923    // Promote allocas to registers.924    FPM->add(createPromoteMemoryToRegisterPass());925    // Do simple "peephole" optimizations and bit-twiddling optzns.926    FPM->add(createInstructionCombiningPass());927    // Reassociate expressions.928    FPM->add(createReassociatePass());929    // Eliminate Common SubExpressions.930    FPM->add(createGVNPass());931    // Simplify the control flow graph (deleting unreachable blocks, etc).932    FPM->add(createCFGSimplificationPass());933    FPM->doInitialization();934 935    // For each function in the module936    Module::iterator it;937    Module::iterator end = M->end();938    for (it = M->begin(); it != end; ++it) {939      // Run the FPM on this function940      FPM->run(*it);941    }942 943    // We don't need this anymore944    delete FPM;945  }946 947  // Store this engine948  EngineMap[M] = NewEngine;949  NewEngine->finalizeObject();950 951  return NewEngine;952}953 954void *MCJITHelper::getPointerToNamedFunction(const std::string &Name)955{956  // Look for the functions in our modules, compiling only as necessary957  ModuleVector::iterator begin = Modules.begin();958  ModuleVector::iterator end = Modules.end();959  ModuleVector::iterator it;960  for (it = begin; it != end; ++it) {961    Function *F = (*it)->getFunction(Name);962    if (F && !F->empty()) {963      std::map<Module*, ExecutionEngine*>::iterator eeIt = EngineMap.find(*it);964      if (eeIt != EngineMap.end()) {965        void *P = eeIt->second->getPointerToFunction(F);966        if (P)967          return P;968      } else {969        ExecutionEngine *EE = compileModule(*it);970        void *P = EE->getPointerToFunction(F);971        if (P)972          return P;973      }974    }975  }976  return NULL;977}978 979void MCJITHelper::addModule(Module* M) {980  Modules.push_back(M);981}982 983void MCJITHelper::dump()984{985  ModuleVector::iterator begin = Modules.begin();986  ModuleVector::iterator end = Modules.end();987  ModuleVector::iterator it;988  for (it = begin; it != end; ++it)989    (*it)->dump();990}991 992//===----------------------------------------------------------------------===//993// Code Generation994//===----------------------------------------------------------------------===//995 996static MCJITHelper *TheHelper;997static LLVMContext TheContext;998static IRBuilder<> Builder(TheContext);999static std::map<std::string, AllocaInst*> NamedValues;1000 1001Value *ErrorV(const char *Str) { Error(Str); return 0; }1002 1003/// CreateEntryBlockAlloca - Create an alloca instruction in the entry block of1004/// the function.  This is used for mutable variables etc.1005static AllocaInst *CreateEntryBlockAlloca(Function *TheFunction,1006                                          const std::string &VarName) {1007  IRBuilder<> TmpB(&TheFunction->getEntryBlock(),1008                 TheFunction->getEntryBlock().begin());1009  return TmpB.CreateAlloca(Type::getDoubleTy(TheContext), 0, VarName.c_str());1010}1011 1012Value *NumberExprAST::Codegen() {1013  return ConstantFP::get(TheContext, APFloat(Val));1014}1015 1016Value *VariableExprAST::Codegen() {1017  // Look this variable up in the function.1018  Value *V = NamedValues[Name];1019  char ErrStr[256];1020  sprintf(ErrStr, "Unknown variable name %s", Name.c_str());1021  if (V == 0) return ErrorV(ErrStr);1022 1023  // Load the value.1024  return Builder.CreateLoad(V, Name.c_str());1025}1026 1027Value *UnaryExprAST::Codegen() {1028  Value *OperandV = Operand->Codegen();1029  if (OperandV == 0) return 0;1030 1031  Function *F = TheHelper->getFunction(MakeLegalFunctionName(std::string("unary")+Opcode));1032  if (F == 0)1033    return ErrorV("Unknown unary operator");1034 1035  return Builder.CreateCall(F, OperandV, "unop");1036}1037 1038Value *BinaryExprAST::Codegen() {1039  // Special case '=' because we don't want to emit the LHS as an expression.1040  if (Op == '=') {1041    // Assignment requires the LHS to be an identifier.1042    VariableExprAST *LHSE = static_cast<VariableExprAST*>(LHS);1043    if (!LHSE)1044      return ErrorV("destination of '=' must be a variable");1045    // Codegen the RHS.1046    Value *Val = RHS->Codegen();1047    if (Val == 0) return 0;1048 1049    // Look up the name.1050    Value *Variable = NamedValues[LHSE->getName()];1051    if (Variable == 0) return ErrorV("Unknown variable name");1052 1053    Builder.CreateStore(Val, Variable);1054    return Val;1055  }1056 1057  Value *L = LHS->Codegen();1058  Value *R = RHS->Codegen();1059  if (L == 0 || R == 0) return 0;1060 1061  switch (Op) {1062  case '+': return Builder.CreateFAdd(L, R, "addtmp");1063  case '-': return Builder.CreateFSub(L, R, "subtmp");1064  case '*': return Builder.CreateFMul(L, R, "multmp");1065  case '/': return Builder.CreateFDiv(L, R, "divtmp");1066  case '<':1067    L = Builder.CreateFCmpULT(L, R, "cmptmp");1068    // Convert bool 0/1 to double 0.0 or 1.01069    return Builder.CreateUIToFP(L, Type::getDoubleTy(TheContext), "booltmp");1070  default: break;1071  }1072 1073  // If it wasn't a builtin binary operator, it must be a user defined one. Emit1074  // a call to it.1075  Function *F = TheHelper->getFunction(MakeLegalFunctionName(std::string("binary")+Op));1076  assert(F && "binary operator not found!");1077 1078  Value *Ops[] = { L, R };1079  return Builder.CreateCall(F, Ops, "binop");1080}1081 1082Value *CallExprAST::Codegen() {1083  // Look up the name in the global module table.1084  Function *CalleeF = TheHelper->getFunction(Callee);1085  if (CalleeF == 0)1086    return ErrorV("Unknown function referenced");1087 1088  // If argument mismatch error.1089  if (CalleeF->arg_size() != Args.size())1090    return ErrorV("Incorrect # arguments passed");1091 1092  std::vector<Value*> ArgsV;1093  for (unsigned i = 0, e = Args.size(); i != e; ++i) {1094    ArgsV.push_back(Args[i]->Codegen());1095    if (ArgsV.back() == 0) return 0;1096  }1097 1098  return Builder.CreateCall(CalleeF, ArgsV, "calltmp");1099}1100 1101Value *IfExprAST::Codegen() {1102  Value *CondV = Cond->Codegen();1103  if (CondV == 0) return 0;1104 1105  // Convert condition to a bool by comparing equal to 0.0.1106  CondV = Builder.CreateFCmpONE(1107      CondV, ConstantFP::get(TheContext, APFloat(0.0)), "ifcond");1108 1109  Function *TheFunction = Builder.GetInsertBlock()->getParent();1110 1111  // Create blocks for the then and else cases.  Insert the 'then' block at the1112  // end of the function.1113  BasicBlock *ThenBB = BasicBlock::Create(TheContext, "then", TheFunction);1114  BasicBlock *ElseBB = BasicBlock::Create(TheContext, "else");1115  BasicBlock *MergeBB = BasicBlock::Create(TheContext, "ifcont");1116 1117  Builder.CreateCondBr(CondV, ThenBB, ElseBB);1118 1119  // Emit then value.1120  Builder.SetInsertPoint(ThenBB);1121 1122  Value *ThenV = Then->Codegen();1123  if (ThenV == 0) return 0;1124 1125  Builder.CreateBr(MergeBB);1126  // Codegen of 'Then' can change the current block, update ThenBB for the PHI.1127  ThenBB = Builder.GetInsertBlock();1128 1129  // Emit else block.1130  TheFunction->insert(TheFunction->end(), ElseBB);1131  Builder.SetInsertPoint(ElseBB);1132 1133  Value *ElseV = Else->Codegen();1134  if (ElseV == 0) return 0;1135 1136  Builder.CreateBr(MergeBB);1137  // Codegen of 'Else' can change the current block, update ElseBB for the PHI.1138  ElseBB = Builder.GetInsertBlock();1139 1140  // Emit merge block.1141  TheFunction->insert(TheFunction->end(), MergeBB);1142  Builder.SetInsertPoint(MergeBB);1143  PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(TheContext), 2, "iftmp");1144 1145  PN->addIncoming(ThenV, ThenBB);1146  PN->addIncoming(ElseV, ElseBB);1147  return PN;1148}1149 1150Value *ForExprAST::Codegen() {1151  // Output this as:1152  //   var = alloca double1153  //   ...1154  //   start = startexpr1155  //   store start -> var1156  //   goto loop1157  // loop:1158  //   ...1159  //   bodyexpr1160  //   ...1161  // loopend:1162  //   step = stepexpr1163  //   endcond = endexpr1164  //1165  //   curvar = load var1166  //   nextvar = curvar + step1167  //   store nextvar -> var1168  //   br endcond, loop, endloop1169  // outloop:1170 1171  Function *TheFunction = Builder.GetInsertBlock()->getParent();1172 1173  // Create an alloca for the variable in the entry block.1174  AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);1175 1176  // Emit the start code first, without 'variable' in scope.1177  Value *StartVal = Start->Codegen();1178  if (StartVal == 0) return 0;1179 1180  // Store the value into the alloca.1181  Builder.CreateStore(StartVal, Alloca);1182 1183  // Make the new basic block for the loop header, inserting after current1184  // block.1185  BasicBlock *LoopBB = BasicBlock::Create(TheContext, "loop", TheFunction);1186 1187  // Insert an explicit fall through from the current block to the LoopBB.1188  Builder.CreateBr(LoopBB);1189 1190  // Start insertion in LoopBB.1191  Builder.SetInsertPoint(LoopBB);1192 1193  // Within the loop, the variable is defined equal to the PHI node.  If it1194  // shadows an existing variable, we have to restore it, so save it now.1195  AllocaInst *OldVal = NamedValues[VarName];1196  NamedValues[VarName] = Alloca;1197 1198  // Emit the body of the loop.  This, like any other expr, can change the1199  // current BB.  Note that we ignore the value computed by the body, but don't1200  // allow an error.1201  if (Body->Codegen() == 0)1202    return 0;1203 1204  // Emit the step value.1205  Value *StepVal;1206  if (Step) {1207    StepVal = Step->Codegen();1208    if (StepVal == 0) return 0;1209  } else {1210    // If not specified, use 1.0.1211    StepVal = ConstantFP::get(TheContext, APFloat(1.0));1212  }1213 1214  // Compute the end condition.1215  Value *EndCond = End->Codegen();1216  if (EndCond == 0) return EndCond;1217 1218  // Reload, increment, and restore the alloca.  This handles the case where1219  // the body of the loop mutates the variable.1220  Value *CurVar = Builder.CreateLoad(Alloca, VarName.c_str());1221  Value *NextVar = Builder.CreateFAdd(CurVar, StepVal, "nextvar");1222  Builder.CreateStore(NextVar, Alloca);1223 1224  // Convert condition to a bool by comparing equal to 0.0.1225  EndCond = Builder.CreateFCmpONE(1226      EndCond, ConstantFP::get(TheContext, APFloat(0.0)), "loopcond");1227 1228  // Create the "after loop" block and insert it.1229  BasicBlock *AfterBB =1230      BasicBlock::Create(TheContext, "afterloop", TheFunction);1231 1232  // Insert the conditional branch into the end of LoopEndBB.1233  Builder.CreateCondBr(EndCond, LoopBB, AfterBB);1234 1235  // Any new code will be inserted in AfterBB.1236  Builder.SetInsertPoint(AfterBB);1237 1238  // Restore the unshadowed variable.1239  if (OldVal)1240    NamedValues[VarName] = OldVal;1241  else1242    NamedValues.erase(VarName);1243 1244 1245  // for expr always returns 0.0.1246  return Constant::getNullValue(Type::getDoubleTy(TheContext));1247}1248 1249Value *VarExprAST::Codegen() {1250  std::vector<AllocaInst *> OldBindings;1251 1252  Function *TheFunction = Builder.GetInsertBlock()->getParent();1253 1254  // Register all variables and emit their initializer.1255  for (unsigned i = 0, e = VarNames.size(); i != e; ++i) {1256    const std::string &VarName = VarNames[i].first;1257    ExprAST *Init = VarNames[i].second;1258 1259    // Emit the initializer before adding the variable to scope, this prevents1260    // the initializer from referencing the variable itself, and permits stuff1261    // like this:1262    //  var a = 1 in1263    //    var a = a in ...   # refers to outer 'a'.1264    Value *InitVal;1265    if (Init) {1266      InitVal = Init->Codegen();1267      if (InitVal == 0) return 0;1268    } else { // If not specified, use 0.0.1269      InitVal = ConstantFP::get(TheContext, APFloat(0.0));1270    }1271 1272    AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);1273    Builder.CreateStore(InitVal, Alloca);1274 1275    // Remember the old variable binding so that we can restore the binding when1276    // we unrecurse.1277    OldBindings.push_back(NamedValues[VarName]);1278 1279    // Remember this binding.1280    NamedValues[VarName] = Alloca;1281  }1282 1283  // Codegen the body, now that all vars are in scope.1284  Value *BodyVal = Body->Codegen();1285  if (BodyVal == 0) return 0;1286 1287  // Pop all our variables from scope.1288  for (unsigned i = 0, e = VarNames.size(); i != e; ++i)1289    NamedValues[VarNames[i].first] = OldBindings[i];1290 1291  // Return the body computation.1292  return BodyVal;1293}1294 1295Function *PrototypeAST::Codegen() {1296  // Make the function type:  double(double,double) etc.1297  std::vector<Type *> Doubles(Args.size(), Type::getDoubleTy(TheContext));1298  FunctionType *FT =1299      FunctionType::get(Type::getDoubleTy(TheContext), Doubles, false);1300 1301  std::string FnName = MakeLegalFunctionName(Name);1302 1303  Module* M = TheHelper->getModuleForNewFunction();1304 1305  Function *F = Function::Create(FT, Function::ExternalLinkage, FnName, M);1306 1307  // If F conflicted, there was already something named 'FnName'.  If it has a1308  // body, don't allow redefinition or reextern.1309  if (F->getName() != FnName) {1310    // Delete the one we just made and get the existing one.1311    F->eraseFromParent();1312    F = M->getFunction(Name);1313 1314    // If F already has a body, reject this.1315    if (!F->empty()) {1316      ErrorF("redefinition of function");1317      return 0;1318    }1319 1320    // If F took a different number of args, reject.1321    if (F->arg_size() != Args.size()) {1322      ErrorF("redefinition of function with different # args");1323      return 0;1324    }1325  }1326 1327  // Set names for all arguments.1328  unsigned Idx = 0;1329  for (Function::arg_iterator AI = F->arg_begin(); Idx != Args.size();1330       ++AI, ++Idx)1331    AI->setName(Args[Idx]);1332 1333  return F;1334}1335 1336/// CreateArgumentAllocas - Create an alloca for each argument and register the1337/// argument in the symbol table so that references to it will succeed.1338void PrototypeAST::CreateArgumentAllocas(Function *F) {1339  Function::arg_iterator AI = F->arg_begin();1340  for (unsigned Idx = 0, e = Args.size(); Idx != e; ++Idx, ++AI) {1341    // Create an alloca for this variable.1342    AllocaInst *Alloca = CreateEntryBlockAlloca(F, Args[Idx]);1343 1344    // Store the initial value into the alloca.1345    Builder.CreateStore(AI, Alloca);1346 1347    // Add arguments to variable symbol table.1348    NamedValues[Args[Idx]] = Alloca;1349  }1350}1351 1352Function *FunctionAST::Codegen() {1353  NamedValues.clear();1354 1355  Function *TheFunction = Proto->Codegen();1356  if (TheFunction == 0)1357    return 0;1358 1359  // If this is an operator, install it.1360  if (Proto->isBinaryOp())1361    BinopPrecedence[Proto->getOperatorName()] = Proto->getBinaryPrecedence();1362 1363  // Create a new basic block to start insertion into.1364  BasicBlock *BB = BasicBlock::Create(TheContext, "entry", TheFunction);1365  Builder.SetInsertPoint(BB);1366 1367  // Add all arguments to the symbol table and create their allocas.1368  Proto->CreateArgumentAllocas(TheFunction);1369 1370  if (Value *RetVal = Body->Codegen()) {1371    // Finish off the function.1372    Builder.CreateRet(RetVal);1373 1374    // Validate the generated code, checking for consistency.1375    verifyFunction(*TheFunction);1376 1377    return TheFunction;1378  }1379 1380  // Error reading body, remove function.1381  TheFunction->eraseFromParent();1382 1383  if (Proto->isBinaryOp())1384    BinopPrecedence.erase(Proto->getOperatorName());1385  return 0;1386}1387 1388//===----------------------------------------------------------------------===//1389// Top-Level parsing and JIT Driver1390//===----------------------------------------------------------------------===//1391 1392static void HandleDefinition() {1393  if (FunctionAST *F = ParseDefinition()) {1394    TheHelper->closeCurrentModule();1395    if (Function *LF = F->Codegen()) {1396#ifndef MINIMAL_STDERR_OUTPUT1397      fprintf(stderr, "Read function definition:");1398      LF->print(errs());1399      fprintf(stderr, "\n");1400#endif1401    }1402  } else {1403    // Skip token for error recovery.1404    getNextToken();1405  }1406}1407 1408static void HandleExtern() {1409  if (PrototypeAST *P = ParseExtern()) {1410    if (Function *F = P->Codegen()) {1411#ifndef MINIMAL_STDERR_OUTPUT1412      fprintf(stderr, "Read extern: ");1413      F->print(errs());1414      fprintf(stderr, "\n");1415#endif1416    }1417  } else {1418    // Skip token for error recovery.1419    getNextToken();1420  }1421}1422 1423static void HandleTopLevelExpression() {1424  // Evaluate a top-level expression into an anonymous function.1425  if (FunctionAST *F = ParseTopLevelExpr()) {1426    if (Function *LF = F->Codegen()) {1427      // JIT the function, returning a function pointer.1428      void *FPtr = TheHelper->getPointerToFunction(LF);1429 1430      // Cast it to the right type (takes no arguments, returns a double) so we1431      // can call it as a native function.1432      double (*FP)() = (double (*)())(intptr_t)FPtr;1433#ifdef MINIMAL_STDERR_OUTPUT1434      FP();1435#else1436      fprintf(stderr, "Evaluated to %f\n", FP());1437#endif1438    }1439  } else {1440    // Skip token for error recovery.1441    getNextToken();1442  }1443}1444 1445/// top ::= definition | external | expression | ';'1446static void MainLoop() {1447  while (1) {1448#ifndef MINIMAL_STDERR_OUTPUT1449    fprintf(stderr, "ready> ");1450#endif1451    switch (CurTok) {1452    case tok_eof:    return;1453    case ';':        getNextToken(); break;  // ignore top-level semicolons.1454    case tok_def:    HandleDefinition(); break;1455    case tok_extern: HandleExtern(); break;1456    default:         HandleTopLevelExpression(); break;1457    }1458  }1459}1460 1461//===----------------------------------------------------------------------===//1462// "Library" functions that can be "extern'd" from user code.1463//===----------------------------------------------------------------------===//1464 1465/// putchard - putchar that takes a double and returns 0.1466extern "C"1467double putchard(double X) {1468  putchar((char)X);1469  return 0;1470}1471 1472/// printd - printf that takes a double prints it as "%f\n", returning 0.1473extern "C"1474double printd(double X) {1475  printf("%f", X);1476  return 0;1477}1478 1479extern "C"1480double printlf() {1481  printf("\n");1482  return 0;1483}1484 1485//===----------------------------------------------------------------------===//1486// Command line input file handler1487//===----------------------------------------------------------------------===//1488 1489Module* parseInputIR(std::string InputFile) {1490  SMDiagnostic Err;1491  Module *M = ParseIRFile(InputFile, Err, TheContext);1492  if (!M) {1493    Err.print("IR parsing failed: ", errs());1494    return NULL;1495  }1496 1497  char ModID[256];1498  sprintf(ModID, "IR:%s", InputFile.c_str());1499  M->setModuleIdentifier(ModID);1500 1501  TheHelper->addModule(M);1502  return M;1503}1504 1505//===----------------------------------------------------------------------===//1506// Main driver code.1507//===----------------------------------------------------------------------===//1508 1509int main(int argc, char **argv) {1510  InitializeNativeTarget();1511  InitializeNativeTargetAsmPrinter();1512  InitializeNativeTargetAsmParser();1513  LLVMContext &Context = TheContext;1514 1515  cl::ParseCommandLineOptions(argc, argv,1516                              "Kaleidoscope example program\n");1517 1518  // Install standard binary operators.1519  // 1 is lowest precedence.1520  BinopPrecedence['='] = 2;1521  BinopPrecedence['<'] = 10;1522  BinopPrecedence['+'] = 20;1523  BinopPrecedence['-'] = 20;1524  BinopPrecedence['/'] = 40;1525  BinopPrecedence['*'] = 40;  // highest.1526 1527  // Prime the first token.1528#ifndef MINIMAL_STDERR_OUTPUT1529  fprintf(stderr, "ready> ");1530#endif1531  getNextToken();1532 1533  // Make the helper, which holds all the code.1534  TheHelper = new MCJITHelper(Context);1535 1536  if (!InputIR.empty()) {1537    parseInputIR(InputIR);1538  }1539 1540  // Run the main "interpreter loop" now.1541  MainLoop();1542 1543#ifndef MINIMAL_STDERR_OUTPUT1544  // Print out all of the generated code.1545  TheHelper->print(errs());1546#endif1547 1548  return 0;1549}1550