llvm/examples/Kaleidoscope/MCJIT/lazy/toy.cpp

   1 #define MINIMAL_STDERR_OUTPUT
   2
   3 #include "llvm/Analysis/Passes.h"
   4 #include "llvm/ExecutionEngine/ExecutionEngine.h"
   5 #include "llvm/ExecutionEngine/MCJIT.h"
   6 #include "llvm/ExecutionEngine/SectionMemoryManager.h"
   7 #include "llvm/IR/DataLayout.h"
   8 #include "llvm/IR/DerivedTypes.h"
   9 #include "llvm/IR/IRBuilder.h"
  10 #include "llvm/IR/LLVMContext.h"
  11 #include "llvm/IR/LegacyPassManager.h"
  12 #include "llvm/IR/Module.h"
  13 #include "llvm/IR/Verifier.h"
  14 #include "llvm/Support/TargetSelect.h"
  15 #include "llvm/Transforms/Scalar.h"
  16 #include <cctype>
  17 #include <cstdio>
  18 #include <map>
  19 #include <string>
  20 #include <vector>
  21 using namespace llvm;
  22
  23 //===----------------------------------------------------------------------===//
  24 // Lexer
  25 //===----------------------------------------------------------------------===//
  26
  27 // The lexer returns tokens [0-255] if it is an unknown character, otherwise one
  28 // of these for known things.
  29 enum Token {
  30   tok_eof = -1,
  31
  32   // commands
  33   tok_def = -2, tok_extern = -3,
  34
  35   // primary
  36   tok_identifier = -4, tok_number = -5,
  37
  38   // control
  39   tok_if = -6, tok_then = -7, tok_else = -8,
  40   tok_for = -9, tok_in = -10,
  41
  42   // operators
  43   tok_binary = -11, tok_unary = -12,
  44
  45   // var definition
  46   tok_var = -13
  47 };
  48
  49 static std::string IdentifierStr;  // Filled in if tok_identifier
  50 static double NumVal;              // Filled in if tok_number
  51
  52 /// gettok - Return the next token from standard input.
  53 static int gettok() {
  54   static int LastChar = ' ';
  55
  56   // Skip any whitespace.
  57   while (isspace(LastChar))
  58     LastChar = getchar();
  59
  60   if (isalpha(LastChar)) { // identifier: [a-zA-Z][a-zA-Z0-9]*
  61     IdentifierStr = LastChar;
  62     while (isalnum((LastChar = getchar())))
  63       IdentifierStr += LastChar;
  64
  65     if (IdentifierStr == "def") return tok_def;
  66     if (IdentifierStr == "extern") return tok_extern;
  67     if (IdentifierStr == "if") return tok_if;
  68     if (IdentifierStr == "then") return tok_then;
  69     if (IdentifierStr == "else") return tok_else;
  70     if (IdentifierStr == "for") return tok_for;
  71     if (IdentifierStr == "in") return tok_in;
  72     if (IdentifierStr == "binary") return tok_binary;
  73     if (IdentifierStr == "unary") return tok_unary;
  74     if (IdentifierStr == "var") return tok_var;
  75     return tok_identifier;
  76   }
  77
  78   if (isdigit(LastChar) || LastChar == '.') {   // Number: [0-9.]+
  79     std::string NumStr;
  80     do {
  81       NumStr += LastChar;
  82       LastChar = getchar();
  83     } while (isdigit(LastChar) || LastChar == '.');
  84
  85     NumVal = strtod(NumStr.c_str(), 0);
  86     return tok_number;
  87   }
  88
  89   if (LastChar == '#') {
  90     // Comment until end of line.
  91     do LastChar = getchar();
  92     while (LastChar != EOF && LastChar != '\n' && LastChar != '\r');
  93
  94     if (LastChar != EOF)
  95       return gettok();
  96   }
  97
  98   // Check for end of file.  Don't eat the EOF.
  99   if (LastChar == EOF)
 100     return tok_eof;
 101
 102   // Otherwise, just return the character as its ascii value.
 103   int ThisChar = LastChar;
 104   LastChar = getchar();
 105   return ThisChar;
 106 }
 107
 108 //===----------------------------------------------------------------------===//
 109 // Abstract Syntax Tree (aka Parse Tree)
 110 //===----------------------------------------------------------------------===//
 111
 112 /// ExprAST - Base class for all expression nodes.
 113 class ExprAST {
 114 public:
 115   virtual ~ExprAST() {}
 116   virtual Value *Codegen() = 0;
 117 };
 118
 119 /// NumberExprAST - Expression class for numeric literals like "1.0".
 120 class NumberExprAST : public ExprAST {
 121   double Val;
 122 public:
 123   NumberExprAST(double val) : Val(val) {}
 124   virtual Value *Codegen();
 125 };
 126
 127 /// VariableExprAST - Expression class for referencing a variable, like "a".
 128 class VariableExprAST : public ExprAST {
 129   std::string Name;
 130 public:
 131   VariableExprAST(const std::string &name) : Name(name) {}
 132   const std::string &getName() const { return Name; }
 133   virtual Value *Codegen();
 134 };
 135
 136 /// UnaryExprAST - Expression class for a unary operator.
 137 class UnaryExprAST : public ExprAST {
 138   char Opcode;
 139   ExprAST *Operand;
 140 public:
 141   UnaryExprAST(char opcode, ExprAST *operand)
 142     : Opcode(opcode), Operand(operand) {}
 143   virtual Value *Codegen();
 144 };
 145
 146 /// BinaryExprAST - Expression class for a binary operator.
 147 class BinaryExprAST : public ExprAST {
 148   char Op;
 149   ExprAST *LHS, *RHS;
 150 public:
 151   BinaryExprAST(char op, ExprAST *lhs, ExprAST *rhs)
 152     : Op(op), LHS(lhs), RHS(rhs) {}
 153   virtual Value *Codegen();
 154 };
 155
 156 /// CallExprAST - Expression class for function calls.
 157 class CallExprAST : public ExprAST {
 158   std::string Callee;
 159   std::vector<ExprAST*> Args;
 160 public:
 161   CallExprAST(const std::string &callee, std::vector<ExprAST*> &args)
 162     : Callee(callee), Args(args) {}
 163   virtual Value *Codegen();
 164 };
 165
 166 /// IfExprAST - Expression class for if/then/else.
 167 class IfExprAST : public ExprAST {
 168   ExprAST *Cond, *Then, *Else;
 169 public:
 170   IfExprAST(ExprAST *cond, ExprAST *then, ExprAST *_else)
 171   : Cond(cond), Then(then), Else(_else) {}
 172   virtual Value *Codegen();
 173 };
 174
 175 /// ForExprAST - Expression class for for/in.
 176 class ForExprAST : public ExprAST {
 177   std::string VarName;
 178   ExprAST *Start, *End, *Step, *Body;
 179 public:
 180   ForExprAST(const std::string &varname, ExprAST *start, ExprAST *end,
 181              ExprAST *step, ExprAST *body)
 182     : VarName(varname), Start(start), End(end), Step(step), Body(body) {}
 183   virtual Value *Codegen();
 184 };
 185
 186 /// VarExprAST - Expression class for var/in
 187 class VarExprAST : public ExprAST {
 188   std::vector<std::pair<std::string, ExprAST*> > VarNames;
 189   ExprAST *Body;
 190 public:
 191   VarExprAST(const std::vector<std::pair<std::string, ExprAST*> > &varnames,
 192              ExprAST *body)
 193   : VarNames(varnames), Body(body) {}
 194
 195   virtual Value *Codegen();
 196 };
 197
 198 /// PrototypeAST - This class represents the "prototype" for a function,
 199 /// which captures its argument names as well as if it is an operator.
 200 class PrototypeAST {
 201   std::string Name;
 202   std::vector<std::string> Args;
 203   bool isOperator;
 204   unsigned Precedence;  // Precedence if a binary op.
 205 public:
 206   PrototypeAST(const std::string &name, const std::vector<std::string> &args,
 207                bool isoperator = false, unsigned prec = 0)
 208   : Name(name), Args(args), isOperator(isoperator), Precedence(prec) {}
 209
 210   bool isUnaryOp() const { return isOperator && Args.size() == 1; }
 211   bool isBinaryOp() const { return isOperator && Args.size() == 2; }
 212
 213   char getOperatorName() const {
 214     assert(isUnaryOp() || isBinaryOp());
 215     return Name[Name.size()-1];
 216   }
 217
 218   unsigned getBinaryPrecedence() const { return Precedence; }
 219
 220   Function *Codegen();
 221
 222   void CreateArgumentAllocas(Function *F);
 223 };
 224
 225 /// FunctionAST - This class represents a function definition itself.
 226 class FunctionAST {
 227   PrototypeAST *Proto;
 228   ExprAST *Body;
 229 public:
 230   FunctionAST(PrototypeAST *proto, ExprAST *body)
 231     : Proto(proto), Body(body) {}
 232
 233   Function *Codegen();
 234 };
 235
 236 //===----------------------------------------------------------------------===//
 237 // Parser
 238 //===----------------------------------------------------------------------===//
 239
 240 /// CurTok/getNextToken - Provide a simple token buffer.  CurTok is the current
 241 /// token the parser is looking at.  getNextToken reads another token from the
 242 /// lexer and updates CurTok with its results.
 243 static int CurTok;
 244 static int getNextToken() {
 245   return CurTok = gettok();
 246 }
 247
 248 /// BinopPrecedence - This holds the precedence for each binary operator that is
 249 /// defined.
 250 static std::map<char, int> BinopPrecedence;
 251
 252 /// GetTokPrecedence - Get the precedence of the pending binary operator token.
 253 static int GetTokPrecedence() {
 254   if (!isascii(CurTok))
 255     return -1;
 256
 257   // Make sure it's a declared binop.
 258   int TokPrec = BinopPrecedence[CurTok];
 259   if (TokPrec <= 0) return -1;
 260   return TokPrec;
 261 }
 262
 263 /// Error* - These are little helper functions for error handling.
 264 ExprAST *Error(const char *Str) { fprintf(stderr, "Error: %s\n", Str);return 0;}
 265 PrototypeAST *ErrorP(const char *Str) { Error(Str); return 0; }
 266 FunctionAST *ErrorF(const char *Str) { Error(Str); return 0; }
 267
 268 static ExprAST *ParseExpression();
 269
 270 /// identifierexpr
 271 ///   ::= identifier
 272 ///   ::= identifier '(' expression* ')'
 273 static ExprAST *ParseIdentifierExpr() {
 274   std::string IdName = IdentifierStr;
 275
 276   getNextToken();  // eat identifier.
 277
 278   if (CurTok != '(') // Simple variable ref.
 279     return new VariableExprAST(IdName);
 280
 281   // Call.
 282   getNextToken();  // eat (
 283   std::vector<ExprAST*> Args;
 284   if (CurTok != ')') {
 285     while (1) {
 286       ExprAST *Arg = ParseExpression();
 287       if (!Arg) return 0;
 288       Args.push_back(Arg);
 289
 290       if (CurTok == ')') break;
 291
 292       if (CurTok != ',')
 293         return Error("Expected ')' or ',' in argument list");
 294       getNextToken();
 295     }
 296   }
 297
 298   // Eat the ')'.
 299   getNextToken();
 300
 301   return new CallExprAST(IdName, Args);
 302 }
 303
 304 /// numberexpr ::= number
 305 static ExprAST *ParseNumberExpr() {
 306   ExprAST *Result = new NumberExprAST(NumVal);
 307   getNextToken(); // consume the number
 308   return Result;
 309 }
 310
 311 /// parenexpr ::= '(' expression ')'
 312 static ExprAST *ParseParenExpr() {
 313   getNextToken();  // eat (.
 314   ExprAST *V = ParseExpression();
 315   if (!V) return 0;
 316
 317   if (CurTok != ')')
 318     return Error("expected ')'");
 319   getNextToken();  // eat ).
 320   return V;
 321 }
 322
 323 /// ifexpr ::= 'if' expression 'then' expression 'else' expression
 324 static ExprAST *ParseIfExpr() {
 325   getNextToken();  // eat the if.
 326
 327   // condition.
 328   ExprAST *Cond = ParseExpression();
 329   if (!Cond) return 0;
 330
 331   if (CurTok != tok_then)
 332     return Error("expected then");
 333   getNextToken();  // eat the then
 334
 335   ExprAST *Then = ParseExpression();
 336   if (Then == 0) return 0;
 337
 338   if (CurTok != tok_else)
 339     return Error("expected else");
 340
 341   getNextToken();
 342
 343   ExprAST *Else = ParseExpression();
 344   if (!Else) return 0;
 345
 346   return new IfExprAST(Cond, Then, Else);
 347 }
 348
 349 /// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression
 350 static ExprAST *ParseForExpr() {
 351   getNextToken();  // eat the for.
 352
 353   if (CurTok != tok_identifier)
 354     return Error("expected identifier after for");
 355
 356   std::string IdName = IdentifierStr;
 357   getNextToken();  // eat identifier.
 358
 359   if (CurTok != '=')
 360     return Error("expected '=' after for");
 361   getNextToken();  // eat '='.
 362
 363
 364   ExprAST *Start = ParseExpression();
 365   if (Start == 0) return 0;
 366   if (CurTok != ',')
 367     return Error("expected ',' after for start value");
 368   getNextToken();
 369
 370   ExprAST *End = ParseExpression();
 371   if (End == 0) return 0;
 372
 373   // The step value is optional.
 374   ExprAST *Step = 0;
 375   if (CurTok == ',') {
 376     getNextToken();
 377     Step = ParseExpression();
 378     if (Step == 0) return 0;
 379   }
 380
 381   if (CurTok != tok_in)
 382     return Error("expected 'in' after for");
 383   getNextToken();  // eat 'in'.
 384
 385   ExprAST *Body = ParseExpression();
 386   if (Body == 0) return 0;
 387
 388   return new ForExprAST(IdName, Start, End, Step, Body);
 389 }
 390
 391 /// varexpr ::= 'var' identifier ('=' expression)?
 392 //                    (',' identifier ('=' expression)?)* 'in' expression
 393 static ExprAST *ParseVarExpr() {
 394   getNextToken();  // eat the var.
 395
 396   std::vector<std::pair<std::string, ExprAST*> > VarNames;
 397
 398   // At least one variable name is required.
 399   if (CurTok != tok_identifier)
 400     return Error("expected identifier after var");
 401
 402   while (1) {
 403     std::string Name = IdentifierStr;
 404     getNextToken();  // eat identifier.
 405
 406     // Read the optional initializer.
 407     ExprAST *Init = 0;
 408     if (CurTok == '=') {
 409       getNextToken(); // eat the '='.
 410
 411       Init = ParseExpression();
 412       if (Init == 0) return 0;
 413     }
 414
 415     VarNames.push_back(std::make_pair(Name, Init));
 416
 417     // End of var list, exit loop.
 418     if (CurTok != ',') break;
 419     getNextToken(); // eat the ','.
 420
 421     if (CurTok != tok_identifier)
 422       return Error("expected identifier list after var");
 423   }
 424
 425   // At this point, we have to have 'in'.
 426   if (CurTok != tok_in)
 427     return Error("expected 'in' keyword after 'var'");
 428   getNextToken();  // eat 'in'.
 429
 430   ExprAST *Body = ParseExpression();
 431   if (Body == 0) return 0;
 432
 433   return new VarExprAST(VarNames, Body);
 434 }
 435
 436 /// primary
 437 ///   ::= identifierexpr
 438 ///   ::= numberexpr
 439 ///   ::= parenexpr
 440 ///   ::= ifexpr
 441 ///   ::= forexpr
 442 ///   ::= varexpr
 443 static ExprAST *ParsePrimary() {
 444   switch (CurTok) {
 445   default: return Error("unknown token when expecting an expression");
 446   case tok_identifier: return ParseIdentifierExpr();
 447   case tok_number:     return ParseNumberExpr();
 448   case '(':            return ParseParenExpr();
 449   case tok_if:         return ParseIfExpr();
 450   case tok_for:        return ParseForExpr();
 451   case tok_var:        return ParseVarExpr();
 452   }
 453 }
 454
 455 /// unary
 456 ///   ::= primary
 457 ///   ::= '!' unary
 458 static ExprAST *ParseUnary() {
 459   // If the current token is not an operator, it must be a primary expr.
 460   if (!isascii(CurTok) || CurTok == '(' || CurTok == ',')
 461     return ParsePrimary();
 462
 463   // If this is a unary operator, read it.
 464   int Opc = CurTok;
 465   getNextToken();
 466   if (ExprAST *Operand = ParseUnary())
 467     return new UnaryExprAST(Opc, Operand);
 468   return 0;
 469 }
 470
 471 /// binoprhs
 472 ///   ::= ('+' unary)*
 473 static ExprAST *ParseBinOpRHS(int ExprPrec, ExprAST *LHS) {
 474   // If this is a binop, find its precedence.
 475   while (1) {
 476     int TokPrec = GetTokPrecedence();
 477
 478     // If this is a binop that binds at least as tightly as the current binop,
 479     // consume it, otherwise we are done.
 480     if (TokPrec < ExprPrec)
 481       return LHS;
 482
 483     // Okay, we know this is a binop.
 484     int BinOp = CurTok;
 485     getNextToken();  // eat binop
 486
 487     // Parse the unary expression after the binary operator.
 488     ExprAST *RHS = ParseUnary();
 489     if (!RHS) return 0;
 490
 491     // If BinOp binds less tightly with RHS than the operator after RHS, let
 492     // the pending operator take RHS as its LHS.
 493     int NextPrec = GetTokPrecedence();
 494     if (TokPrec < NextPrec) {
 495       RHS = ParseBinOpRHS(TokPrec+1, RHS);
 496       if (RHS == 0) return 0;
 497     }
 498
 499     // Merge LHS/RHS.
 500     LHS = new BinaryExprAST(BinOp, LHS, RHS);
 501   }
 502 }
 503
 504 /// expression
 505 ///   ::= unary binoprhs
 506 ///
 507 static ExprAST *ParseExpression() {
 508   ExprAST *LHS = ParseUnary();
 509   if (!LHS) return 0;
 510
 511   return ParseBinOpRHS(0, LHS);
 512 }
 513
 514 /// prototype
 515 ///   ::= id '(' id* ')'
 516 ///   ::= binary LETTER number? (id, id)
 517 ///   ::= unary LETTER (id)
 518 static PrototypeAST *ParsePrototype() {
 519   std::string FnName;
 520
 521   unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.
 522   unsigned BinaryPrecedence = 30;
 523
 524   switch (CurTok) {
 525   default:
 526     return ErrorP("Expected function name in prototype");
 527   case tok_identifier:
 528     FnName = IdentifierStr;
 529     Kind = 0;
 530     getNextToken();
 531     break;
 532   case tok_unary:
 533     getNextToken();
 534     if (!isascii(CurTok))
 535       return ErrorP("Expected unary operator");
 536     FnName = "unary";
 537     FnName += (char)CurTok;
 538     Kind = 1;
 539     getNextToken();
 540     break;
 541   case tok_binary:
 542     getNextToken();
 543     if (!isascii(CurTok))
 544       return ErrorP("Expected binary operator");
 545     FnName = "binary";
 546     FnName += (char)CurTok;
 547     Kind = 2;
 548     getNextToken();
 549
 550     // Read the precedence if present.
 551     if (CurTok == tok_number) {
 552       if (NumVal < 1 || NumVal > 100)
 553         return ErrorP("Invalid precedecnce: must be 1..100");
 554       BinaryPrecedence = (unsigned)NumVal;
 555       getNextToken();
 556     }
 557     break;
 558   }
 559
 560   if (CurTok != '(')
 561     return ErrorP("Expected '(' in prototype");
 562
 563   std::vector<std::string> ArgNames;
 564   while (getNextToken() == tok_identifier)
 565     ArgNames.push_back(IdentifierStr);
 566   if (CurTok != ')')
 567     return ErrorP("Expected ')' in prototype");
 568
 569   // success.
 570   getNextToken();  // eat ')'.
 571
 572   // Verify right number of names for operator.
 573   if (Kind && ArgNames.size() != Kind)
 574     return ErrorP("Invalid number of operands for operator");
 575
 576   return new PrototypeAST(FnName, ArgNames, Kind != 0, BinaryPrecedence);
 577 }
 578
 579 /// definition ::= 'def' prototype expression
 580 static FunctionAST *ParseDefinition() {
 581   getNextToken();  // eat def.
 582   PrototypeAST *Proto = ParsePrototype();
 583   if (Proto == 0) return 0;
 584
 585   if (ExprAST *E = ParseExpression())
 586     return new FunctionAST(Proto, E);
 587   return 0;
 588 }
 589
 590 /// toplevelexpr ::= expression
 591 static FunctionAST *ParseTopLevelExpr() {
 592   if (ExprAST *E = ParseExpression()) {
 593     // Make an anonymous proto.
 594     PrototypeAST *Proto = new PrototypeAST("", std::vector<std::string>());
 595     return new FunctionAST(Proto, E);
 596   }
 597   return 0;
 598 }
 599
 600 /// external ::= 'extern' prototype
 601 static PrototypeAST *ParseExtern() {
 602   getNextToken();  // eat extern.
 603   return ParsePrototype();
 604 }
 605
 606 //===----------------------------------------------------------------------===//
 607 // Quick and dirty hack
 608 //===----------------------------------------------------------------------===//
 609
 610 // FIXME: Obviously we can do better than this
 611 std::string GenerateUniqueName(const char *root)
 612 {
 613   static int i = 0;
 614   char s[16];
 615   sprintf(s, "%s%d", root, i++);
 616   std::string S = s;
 617   return S;
 618 }
 619
 620 std::string MakeLegalFunctionName(std::string Name)
 621 {
 622   std::string NewName;
 623   if (!Name.length())
 624       return GenerateUniqueName("anon_func_");
 625
 626   // Start with what we have
 627   NewName = Name;
 628
 629   // Look for a numberic first character
 630   if (NewName.find_first_of("0123456789") == 0) {
 631     NewName.insert(0, 1, 'n');
 632   }
 633
 634   // Replace illegal characters with their ASCII equivalent
 635   std::string legal_elements = "_abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
 636   size_t pos;
 637   while ((pos = NewName.find_first_not_of(legal_elements)) != std::string::npos) {
 638     char old_c = NewName.at(pos);
 639     char new_str[16];
 640     sprintf(new_str, "%d", (int)old_c);
 641     NewName = NewName.replace(pos, 1, new_str);
 642   }
 643
 644   return NewName;
 645 }
 646
 647 //===----------------------------------------------------------------------===//
 648 // MCJIT helper class
 649 //===----------------------------------------------------------------------===//
 650
 651 class MCJITHelper
 652 {
 653 public:
 654   MCJITHelper(LLVMContext& C) : Context(C), OpenModule(NULL) {}
 655   ~MCJITHelper();
 656
 657   Function *getFunction(const std::string FnName);
 658   Module *getModuleForNewFunction();
 659   void *getPointerToFunction(Function* F);
 660   void *getPointerToNamedFunction(const std::string &Name);
 661   ExecutionEngine *compileModule(Module *M);
 662   void closeCurrentModule();
 663   void dump();
 664
 665 private:
 666   typedef std::vector<Module*> ModuleVector;
 667
 668   LLVMContext  &Context;
 669   Module       *OpenModule;
 670   ModuleVector  Modules;
 671   std::map<Module *, ExecutionEngine *> EngineMap;
 672 };
 673
 674 class HelpingMemoryManager : public SectionMemoryManager
 675 {
 676   HelpingMemoryManager(const HelpingMemoryManager&) = delete;
 677   void operator=(const HelpingMemoryManager&) = delete;
 678
 679 public:
 680   HelpingMemoryManager(MCJITHelper *Helper) : MasterHelper(Helper) {}
 681   virtual ~HelpingMemoryManager() {}
 682
 683   /// This method returns the address of the specified function.
 684   /// Our implementation will attempt to find functions in other
 685   /// modules associated with the MCJITHelper to cross link functions
 686   /// from one generated module to another.
 687   ///
 688   /// If \p AbortOnFailure is false and no function with the given name is
 689   /// found, this function returns a null pointer. Otherwise, it prints a
 690   /// message to stderr and aborts.
 691   virtual void *getPointerToNamedFunction(const std::string &Name,
 692                                           bool AbortOnFailure = true);
 693 private:
 694   MCJITHelper *MasterHelper;
 695 };
 696
 697 void *HelpingMemoryManager::getPointerToNamedFunction(const std::string &Name,
 698                                         bool AbortOnFailure)
 699 {
 700   // Try the standard symbol resolution first, but ask it not to abort.
 701   void *pfn = SectionMemoryManager::getPointerToNamedFunction(Name, false);
 702   if (pfn)
 703     return pfn;
 704
 705   pfn = MasterHelper->getPointerToNamedFunction(Name);
 706   if (!pfn && AbortOnFailure)
 707     report_fatal_error("Program used external function '" + Name +
 708                         "' which could not be resolved!");
 709   return pfn;
 710 }
 711
 712 MCJITHelper::~MCJITHelper()
 713 {
 714   // Walk the vector of modules.
 715   ModuleVector::iterator it, end;
 716   for (it = Modules.begin(), end = Modules.end();
 717        it != end; ++it) {
 718     // See if we have an execution engine for this module.
 719     std::map<Module*, ExecutionEngine*>::iterator mapIt = EngineMap.find(*it);
 720     // If we have an EE, the EE owns the module so just delete the EE.
 721     if (mapIt != EngineMap.end()) {
 722       delete mapIt->second;
 723     } else {
 724       // Otherwise, we still own the module.  Delete it now.
 725       delete *it;
 726     }
 727   }
 728 }
 729
 730 Function *MCJITHelper::getFunction(const std::string FnName) {
 731   ModuleVector::iterator begin = Modules.begin();
 732   ModuleVector::iterator end = Modules.end();
 733   ModuleVector::iterator it;
 734   for (it = begin; it != end; ++it) {
 735     Function *F = (*it)->getFunction(FnName);
 736     if (F) {
 737       if (*it == OpenModule)
 738           return F;
 739
 740       assert(OpenModule != NULL);
 741
 742       // This function is in a module that has already been JITed.
 743       // We need to generate a new prototype for external linkage.
 744       Function *PF = OpenModule->getFunction(FnName);
 745       if (PF && !PF->empty()) {
 746         ErrorF("redefinition of function across modules");
 747         return 0;
 748       }
 749
 750       // If we don't have a prototype yet, create one.
 751       if (!PF)
 752         PF = Function::Create(F->getFunctionType(),
 753                                       Function::ExternalLinkage,
 754                                       FnName,
 755                                       OpenModule);
 756       return PF;
 757     }
 758   }
 759   return NULL;
 760 }
 761
 762 Module *MCJITHelper::getModuleForNewFunction() {
 763   // If we have a Module that hasn't been JITed, use that.
 764   if (OpenModule)
 765     return OpenModule;
 766
 767   // Otherwise create a new Module.
 768   std::string ModName = GenerateUniqueName("mcjit_module_");
 769   Module *M = new Module(ModName, Context);
 770   Modules.push_back(M);
 771   OpenModule = M;
 772   return M;
 773 }
 774
 775 void *MCJITHelper::getPointerToFunction(Function* F) {
 776   // Look for this function in an existing module
 777   ModuleVector::iterator begin = Modules.begin();
 778   ModuleVector::iterator end = Modules.end();
 779   ModuleVector::iterator it;
 780   std::string FnName = F->getName();
 781   for (it = begin; it != end; ++it) {
 782     Function *MF = (*it)->getFunction(FnName);
 783     if (MF == F) {
 784       std::map<Module*, ExecutionEngine*>::iterator eeIt = EngineMap.find(*it);
 785       if (eeIt != EngineMap.end()) {
 786         void *P = eeIt->second->getPointerToFunction(F);
 787         if (P)
 788           return P;
 789       } else {
 790         ExecutionEngine *EE = compileModule(*it);
 791         void *P = EE->getPointerToFunction(F);
 792         if (P)
 793           return P;
 794       }
 795     }
 796   }
 797   return NULL;
 798 }
 799
 800 void MCJITHelper::closeCurrentModule() {
 801   OpenModule = NULL;
 802 }
 803
 804 ExecutionEngine *MCJITHelper::compileModule(Module *M) {
 805   if (M == OpenModule)
 806     closeCurrentModule();
 807
 808   std::string ErrStr;
 809   ExecutionEngine *NewEngine = EngineBuilder(M)
 810                                             .setErrorStr(&ErrStr)
 811                                             .setMCJITMemoryManager(new HelpingMemoryManager(this))
 812                                             .create();
 813   if (!NewEngine) {
 814     fprintf(stderr, "Could not create ExecutionEngine: %s\n", ErrStr.c_str());
 815     exit(1);
 816   }
 817
 818   // Create a function pass manager for this engine
 819   FunctionPassManager *FPM = new FunctionPassManager(M);
 820
 821   // Set up the optimizer pipeline.  Start with registering info about how the
 822   // target lays out data structures.
 823   FPM->add(new DataLayout(*NewEngine->getDataLayout()));
 824   // Provide basic AliasAnalysis support for GVN.
 825   FPM->add(createBasicAliasAnalysisPass());
 826   // Promote allocas to registers.
 827   FPM->add(createPromoteMemoryToRegisterPass());
 828   // Do simple "peephole" optimizations and bit-twiddling optzns.
 829   FPM->add(createInstructionCombiningPass());
 830   // Reassociate expressions.
 831   FPM->add(createReassociatePass());
 832   // Eliminate Common SubExpressions.
 833   FPM->add(createGVNPass());
 834   // Simplify the control flow graph (deleting unreachable blocks, etc).
 835   FPM->add(createCFGSimplificationPass());
 836   FPM->doInitialization();
 837
 838   // For each function in the module
 839   Module::iterator it;
 840   Module::iterator end = M->end();
 841   for (it = M->begin(); it != end; ++it) {
 842     // Run the FPM on this function
 843     FPM->run(*it);
 844   }
 845
 846   // We don't need this anymore
 847   delete FPM;
 848
 849   // Store this engine
 850   EngineMap[M] = NewEngine;
 851   NewEngine->finalizeObject();
 852
 853   return NewEngine;
 854 }
 855
 856 void *MCJITHelper::getPointerToNamedFunction(const std::string &Name)
 857 {
 858   // Look for the functions in our modules, compiling only as necessary
 859   ModuleVector::iterator begin = Modules.begin();
 860   ModuleVector::iterator end = Modules.end();
 861   ModuleVector::iterator it;
 862   for (it = begin; it != end; ++it) {
 863     Function *F = (*it)->getFunction(Name);
 864     if (F && !F->empty()) {
 865       std::map<Module*, ExecutionEngine*>::iterator eeIt = EngineMap.find(*it);
 866       if (eeIt != EngineMap.end()) {
 867         void *P = eeIt->second->getPointerToFunction(F);
 868         if (P)
 869           return P;
 870       } else {
 871         ExecutionEngine *EE = compileModule(*it);
 872         void *P = EE->getPointerToFunction(F);
 873         if (P)
 874           return P;
 875       }
 876     }
 877   }
 878   return NULL;
 879 }
 880
 881 void MCJITHelper::dump()
 882 {
 883   ModuleVector::iterator begin = Modules.begin();
 884   ModuleVector::iterator end = Modules.end();
 885   ModuleVector::iterator it;
 886   for (it = begin; it != end; ++it)
 887     (*it)->dump();
 888 }
 889
 890 //===----------------------------------------------------------------------===//
 891 // Code Generation
 892 //===----------------------------------------------------------------------===//
 893
 894 static MCJITHelper *TheHelper;
 895 static LLVMContext TheContext;
 896 static IRBuilder<> Builder(TheContext);
 897 static std::map<std::string, AllocaInst*> NamedValues;
 898
 899 Value *ErrorV(const char *Str) { Error(Str); return 0; }
 900
 901 /// CreateEntryBlockAlloca - Create an alloca instruction in the entry block of
 902 /// the function.  This is used for mutable variables etc.
 903 static AllocaInst *CreateEntryBlockAlloca(Function *TheFunction,
 904                                           const std::string &VarName) {
 905   IRBuilder<> TmpB(&TheFunction->getEntryBlock(),
 906                  TheFunction->getEntryBlock().begin());
 907   return TmpB.CreateAlloca(Type::getDoubleTy(TheContext), 0, VarName.c_str());
 908 }
 909
 910 Value *NumberExprAST::Codegen() {
 911   return ConstantFP::get(TheContext, APFloat(Val));
 912 }
 913
 914 Value *VariableExprAST::Codegen() {
 915   // Look this variable up in the function.
 916   Value *V = NamedValues[Name];
 917   char ErrStr[256];
 918   sprintf(ErrStr, "Unknown variable name %s", Name.c_str());
 919   if (V == 0) return ErrorV(ErrStr);
 920
 921   // Load the value.
 922   return Builder.CreateLoad(V, Name.c_str());
 923 }
 924
 925 Value *UnaryExprAST::Codegen() {
 926   Value *OperandV = Operand->Codegen();
 927   if (OperandV == 0) return 0;
 928
 929   Function *F = TheHelper->getFunction(MakeLegalFunctionName(std::string("unary")+Opcode));
 930   if (F == 0)
 931     return ErrorV("Unknown unary operator");
 932
 933   return Builder.CreateCall(F, OperandV, "unop");
 934 }
 935
 936 Value *BinaryExprAST::Codegen() {
 937   // Special case '=' because we don't want to emit the LHS as an expression.
 938   if (Op == '=') {
 939     // Assignment requires the LHS to be an identifier.
 940     VariableExprAST *LHSE = static_cast<VariableExprAST*>(LHS);
 941     if (!LHSE)
 942       return ErrorV("destination of '=' must be a variable");
 943     // Codegen the RHS.
 944     Value *Val = RHS->Codegen();
 945     if (Val == 0) return 0;
 946
 947     // Look up the name.
 948     Value *Variable = NamedValues[LHSE->getName()];
 949     if (Variable == 0) return ErrorV("Unknown variable name");
 950
 951     Builder.CreateStore(Val, Variable);
 952     return Val;
 953   }
 954
 955   Value *L = LHS->Codegen();
 956   Value *R = RHS->Codegen();
 957   if (L == 0 || R == 0) return 0;
 958
 959   switch (Op) {
 960   case '+': return Builder.CreateFAdd(L, R, "addtmp");
 961   case '-': return Builder.CreateFSub(L, R, "subtmp");
 962   case '*': return Builder.CreateFMul(L, R, "multmp");
 963   case '/': return Builder.CreateFDiv(L, R, "divtmp");
 964   case '<':
 965     L = Builder.CreateFCmpULT(L, R, "cmptmp");
 966     // Convert bool 0/1 to double 0.0 or 1.0
 967     return Builder.CreateUIToFP(L, Type::getDoubleTy(TheContext), "booltmp");
 968   default: break;
 969   }
 970
 971   // If it wasn't a builtin binary operator, it must be a user defined one. Emit
 972   // a call to it.
 973   Function *F = TheHelper->getFunction(MakeLegalFunctionName(std::string("binary")+Op));
 974   assert(F && "binary operator not found!");
 975
 976   Value *Ops[] = { L, R };
 977   return Builder.CreateCall(F, Ops, "binop");
 978 }
 979
 980 Value *CallExprAST::Codegen() {
 981   // Look up the name in the global module table.
 982   Function *CalleeF = TheHelper->getFunction(Callee);
 983   if (CalleeF == 0)
 984     return ErrorV("Unknown function referenced");
 985
 986   // If argument mismatch error.
 987   if (CalleeF->arg_size() != Args.size())
 988     return ErrorV("Incorrect # arguments passed");
 989
 990   std::vector<Value*> ArgsV;
 991   for (unsigned i = 0, e = Args.size(); i != e; ++i) {
 992     ArgsV.push_back(Args[i]->Codegen());
 993     if (ArgsV.back() == 0) return 0;
 994   }
 995
 996   return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
 997 }
 998
 999 Value *IfExprAST::Codegen() {
1000   Value *CondV = Cond->Codegen();
1001   if (CondV == 0) return 0;
1002
1003   // Convert condition to a bool by comparing equal to 0.0.
1004   CondV = Builder.CreateFCmpONE(
1005       CondV, ConstantFP::get(TheContext, APFloat(0.0)), "ifcond");
1006
1007   Function *TheFunction = Builder.GetInsertBlock()->getParent();
1008
1009   // Create blocks for the then and else cases.  Insert the 'then' block at the
1010   // end of the function.
1011   BasicBlock *ThenBB = BasicBlock::Create(TheContext, "then", TheFunction);
1012   BasicBlock *ElseBB = BasicBlock::Create(TheContext, "else");
1013   BasicBlock *MergeBB = BasicBlock::Create(TheContext, "ifcont");
1014
1015   Builder.CreateCondBr(CondV, ThenBB, ElseBB);
1016
1017   // Emit then value.
1018   Builder.SetInsertPoint(ThenBB);
1019
1020   Value *ThenV = Then->Codegen();
1021   if (ThenV == 0) return 0;
1022
1023   Builder.CreateBr(MergeBB);
1024   // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
1025   ThenBB = Builder.GetInsertBlock();
1026
1027   // Emit else block.
1028   TheFunction->insert(TheFunction->end(), ElseBB);
1029   Builder.SetInsertPoint(ElseBB);
1030
1031   Value *ElseV = Else->Codegen();
1032   if (ElseV == 0) return 0;
1033
1034   Builder.CreateBr(MergeBB);
1035   // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
1036   ElseBB = Builder.GetInsertBlock();
1037
1038   // Emit merge block.
1039   TheFunction->insert(TheFunction->end(), MergeBB);
1040   Builder.SetInsertPoint(MergeBB);
1041   PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(TheContext), 2, "iftmp");
1042
1043   PN->addIncoming(ThenV, ThenBB);
1044   PN->addIncoming(ElseV, ElseBB);
1045   return PN;
1046 }
1047
1048 Value *ForExprAST::Codegen() {
1049   // Output this as:
1050   //   var = alloca double
1051   //   ...
1052   //   start = startexpr
1053   //   store start -> var
1054   //   goto loop
1055   // loop:
1056   //   ...
1057   //   bodyexpr
1058   //   ...
1059   // loopend:
1060   //   step = stepexpr
1061   //   endcond = endexpr
1062   //
1063   //   curvar = load var
1064   //   nextvar = curvar + step
1065   //   store nextvar -> var
1066   //   br endcond, loop, endloop
1067   // outloop:
1068
1069   Function *TheFunction = Builder.GetInsertBlock()->getParent();
1070
1071   // Create an alloca for the variable in the entry block.
1072   AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
1073
1074   // Emit the start code first, without 'variable' in scope.
1075   Value *StartVal = Start->Codegen();
1076   if (StartVal == 0) return 0;
1077
1078   // Store the value into the alloca.
1079   Builder.CreateStore(StartVal, Alloca);
1080
1081   // Make the new basic block for the loop header, inserting after current
1082   // block.
1083   BasicBlock *LoopBB = BasicBlock::Create(TheContext, "loop", TheFunction);
1084
1085   // Insert an explicit fall through from the current block to the LoopBB.
1086   Builder.CreateBr(LoopBB);
1087
1088   // Start insertion in LoopBB.
1089   Builder.SetInsertPoint(LoopBB);
1090
1091   // Within the loop, the variable is defined equal to the PHI node.  If it
1092   // shadows an existing variable, we have to restore it, so save it now.
1093   AllocaInst *OldVal = NamedValues[VarName];
1094   NamedValues[VarName] = Alloca;
1095
1096   // Emit the body of the loop.  This, like any other expr, can change the
1097   // current BB.  Note that we ignore the value computed by the body, but don't
1098   // allow an error.
1099   if (Body->Codegen() == 0)
1100     return 0;
1101
1102   // Emit the step value.
1103   Value *StepVal;
1104   if (Step) {
1105     StepVal = Step->Codegen();
1106     if (StepVal == 0) return 0;
1107   } else {
1108     // If not specified, use 1.0.
1109     StepVal = ConstantFP::get(TheContext, APFloat(1.0));
1110   }
1111
1112   // Compute the end condition.
1113   Value *EndCond = End->Codegen();
1114   if (EndCond == 0) return EndCond;
1115
1116   // Reload, increment, and restore the alloca.  This handles the case where
1117   // the body of the loop mutates the variable.
1118   Value *CurVar = Builder.CreateLoad(Alloca, VarName.c_str());
1119   Value *NextVar = Builder.CreateFAdd(CurVar, StepVal, "nextvar");
1120   Builder.CreateStore(NextVar, Alloca);
1121
1122   // Convert condition to a bool by comparing equal to 0.0.
1123   EndCond = Builder.CreateFCmpONE(
1124       EndCond, ConstantFP::get(TheContext, APFloat(0.0)), "loopcond");
1125
1126   // Create the "after loop" block and insert it.
1127   BasicBlock *AfterBB =
1128       BasicBlock::Create(TheContext, "afterloop", TheFunction);
1129
1130   // Insert the conditional branch into the end of LoopEndBB.
1131   Builder.CreateCondBr(EndCond, LoopBB, AfterBB);
1132
1133   // Any new code will be inserted in AfterBB.
1134   Builder.SetInsertPoint(AfterBB);
1135
1136   // Restore the unshadowed variable.
1137   if (OldVal)
1138     NamedValues[VarName] = OldVal;
1139   else
1140     NamedValues.erase(VarName);
1141
1142
1143   // for expr always returns 0.0.
1144   return Constant::getNullValue(Type::getDoubleTy(TheContext));
1145 }
1146
1147 Value *VarExprAST::Codegen() {
1148   std::vector<AllocaInst *> OldBindings;
1149
1150   Function *TheFunction = Builder.GetInsertBlock()->getParent();
1151
1152   // Register all variables and emit their initializer.
1153   for (unsigned i = 0, e = VarNames.size(); i != e; ++i) {
1154     const std::string &VarName = VarNames[i].first;
1155     ExprAST *Init = VarNames[i].second;
1156
1157     // Emit the initializer before adding the variable to scope, this prevents
1158     // the initializer from referencing the variable itself, and permits stuff
1159     // like this:
1160     //  var a = 1 in
1161     //    var a = a in ...   # refers to outer 'a'.
1162     Value *InitVal;
1163     if (Init) {
1164       InitVal = Init->Codegen();
1165       if (InitVal == 0) return 0;
1166     } else { // If not specified, use 0.0.
1167       InitVal = ConstantFP::get(TheContext, APFloat(0.0));
1168     }
1169
1170     AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
1171     Builder.CreateStore(InitVal, Alloca);
1172
1173     // Remember the old variable binding so that we can restore the binding when
1174     // we unrecurse.
1175     OldBindings.push_back(NamedValues[VarName]);
1176
1177     // Remember this binding.
1178     NamedValues[VarName] = Alloca;
1179   }
1180
1181   // Codegen the body, now that all vars are in scope.
1182   Value *BodyVal = Body->Codegen();
1183   if (BodyVal == 0) return 0;
1184
1185   // Pop all our variables from scope.
1186   for (unsigned i = 0, e = VarNames.size(); i != e; ++i)
1187     NamedValues[VarNames[i].first] = OldBindings[i];
1188
1189   // Return the body computation.
1190   return BodyVal;
1191 }
1192
1193 Function *PrototypeAST::Codegen() {
1194   // Make the function type:  double(double,double) etc.
1195   std::vector<Type *> Doubles(Args.size(), Type::getDoubleTy(TheContext));
1196   FunctionType *FT =
1197       FunctionType::get(Type::getDoubleTy(TheContext), Doubles, false);
1198
1199   std::string FnName = MakeLegalFunctionName(Name);
1200
1201   Module* M = TheHelper->getModuleForNewFunction();
1202
1203   Function *F = Function::Create(FT, Function::ExternalLinkage, FnName, M);
1204
1205   // If F conflicted, there was already something named 'FnName'.  If it has a
1206   // body, don't allow redefinition or reextern.
1207   if (F->getName() != FnName) {
1208     // Delete the one we just made and get the existing one.
1209     F->eraseFromParent();
1210     F = M->getFunction(Name);
1211
1212     // If F already has a body, reject this.
1213     if (!F->empty()) {
1214       ErrorF("redefinition of function");
1215       return 0;
1216     }
1217
1218     // If F took a different number of args, reject.
1219     if (F->arg_size() != Args.size()) {
1220       ErrorF("redefinition of function with different # args");
1221       return 0;
1222     }
1223   }
1224
1225   // Set names for all arguments.
1226   unsigned Idx = 0;
1227   for (Function::arg_iterator AI = F->arg_begin(); Idx != Args.size();
1228        ++AI, ++Idx)
1229     AI->setName(Args[Idx]);
1230
1231   return F;
1232 }
1233
1234 /// CreateArgumentAllocas - Create an alloca for each argument and register the
1235 /// argument in the symbol table so that references to it will succeed.
1236 void PrototypeAST::CreateArgumentAllocas(Function *F) {
1237   Function::arg_iterator AI = F->arg_begin();
1238   for (unsigned Idx = 0, e = Args.size(); Idx != e; ++Idx, ++AI) {
1239     // Create an alloca for this variable.
1240     AllocaInst *Alloca = CreateEntryBlockAlloca(F, Args[Idx]);
1241
1242     // Store the initial value into the alloca.
1243     Builder.CreateStore(AI, Alloca);
1244
1245     // Add arguments to variable symbol table.
1246     NamedValues[Args[Idx]] = Alloca;
1247   }
1248 }
1249
1250 Function *FunctionAST::Codegen() {
1251   NamedValues.clear();
1252
1253   Function *TheFunction = Proto->Codegen();
1254   if (TheFunction == 0)
1255     return 0;
1256
1257   // If this is an operator, install it.
1258   if (Proto->isBinaryOp())
1259     BinopPrecedence[Proto->getOperatorName()] = Proto->getBinaryPrecedence();
1260
1261   // Create a new basic block to start insertion into.
1262   BasicBlock *BB = BasicBlock::Create(TheContext, "entry", TheFunction);
1263   Builder.SetInsertPoint(BB);
1264
1265   // Add all arguments to the symbol table and create their allocas.
1266   Proto->CreateArgumentAllocas(TheFunction);
1267
1268   if (Value *RetVal = Body->Codegen()) {
1269     // Finish off the function.
1270     Builder.CreateRet(RetVal);
1271
1272     // Validate the generated code, checking for consistency.
1273     verifyFunction(*TheFunction);
1274
1275     return TheFunction;
1276   }
1277
1278   // Error reading body, remove function.
1279   TheFunction->eraseFromParent();
1280
1281   if (Proto->isBinaryOp())
1282     BinopPrecedence.erase(Proto->getOperatorName());
1283   return 0;
1284 }
1285
1286 //===----------------------------------------------------------------------===//
1287 // Top-Level parsing and JIT Driver
1288 //===----------------------------------------------------------------------===//
1289
1290 static void HandleDefinition() {
1291   if (FunctionAST *F = ParseDefinition()) {
1292     TheHelper->closeCurrentModule();
1293     if (Function *LF = F->Codegen()) {
1294 #ifndef MINIMAL_STDERR_OUTPUT
1295       fprintf(stderr, "Read function definition:");
1296       LF->print(errs());
1297       fprintf(stderr, "\n");
1298 #endif
1299     }
1300   } else {
1301     // Skip token for error recovery.
1302     getNextToken();
1303   }
1304 }
1305
1306 static void HandleExtern() {
1307   if (PrototypeAST *P = ParseExtern()) {
1308     if (Function *F = P->Codegen()) {
1309 #ifndef MINIMAL_STDERR_OUTPUT
1310       fprintf(stderr, "Read extern: ");
1311       F->print(errs());
1312       fprintf(stderr, "\n");
1313 #endif
1314     }
1315   } else {
1316     // Skip token for error recovery.
1317     getNextToken();
1318   }
1319 }
1320
1321 static void HandleTopLevelExpression() {
1322   // Evaluate a top-level expression into an anonymous function.
1323   if (FunctionAST *F = ParseTopLevelExpr()) {
1324     if (Function *LF = F->Codegen()) {
1325       // JIT the function, returning a function pointer.
1326       void *FPtr = TheHelper->getPointerToFunction(LF);
1327
1328       // Cast it to the right type (takes no arguments, returns a double) so we
1329       // can call it as a native function.
1330       double (*FP)() = (double (*)())(intptr_t)FPtr;
1331 #ifdef MINIMAL_STDERR_OUTPUT
1332       FP();
1333 #else
1334       fprintf(stderr, "Evaluated to %f\n", FP());
1335 #endif
1336     }
1337   } else {
1338     // Skip token for error recovery.
1339     getNextToken();
1340   }
1341 }
1342
1343 /// top ::= definition | external | expression | ';'
1344 static void MainLoop() {
1345   while (1) {
1346 #ifndef MINIMAL_STDERR_OUTPUT
1347     fprintf(stderr, "ready> ");
1348 #endif
1349     switch (CurTok) {
1350     case tok_eof:    return;
1351     case ';':        getNextToken(); break;  // ignore top-level semicolons.
1352     case tok_def:    HandleDefinition(); break;
1353     case tok_extern: HandleExtern(); break;
1354     default:         HandleTopLevelExpression(); break;
1355     }
1356   }
1357 }
1358
1359 //===----------------------------------------------------------------------===//
1360 // "Library" functions that can be "extern'd" from user code.
1361 //===----------------------------------------------------------------------===//
1362
1363 /// putchard - putchar that takes a double and returns 0.
1364 extern "C"
1365 double putchard(double X) {
1366   putchar((char)X);
1367   return 0;
1368 }
1369
1370 /// printd - printf that takes a double prints it as "%f\n", returning 0.
1371 extern "C"
1372 double printd(double X) {
1373   printf("%f", X);
1374   return 0;
1375 }
1376
1377 extern "C"
1378 double printlf() {
1379   printf("\n");
1380   return 0;
1381 }
1382
1383 //===----------------------------------------------------------------------===//
1384 // Main driver code.
1385 //===----------------------------------------------------------------------===//
1386
1387 int main() {
1388   InitializeNativeTarget();
1389   InitializeNativeTargetAsmPrinter();
1390   InitializeNativeTargetAsmParser();
1391   LLVMContext &Context = TheContext;
1392
1393   // Install standard binary operators.
1394   // 1 is lowest precedence.
1395   BinopPrecedence['='] = 2;
1396   BinopPrecedence['<'] = 10;
1397   BinopPrecedence['+'] = 20;
1398   BinopPrecedence['-'] = 20;
1399   BinopPrecedence['/'] = 40;
1400   BinopPrecedence['*'] = 40;  // highest.
1401
1402   // Prime the first token.
1403 #ifndef MINIMAL_STDERR_OUTPUT
1404   fprintf(stderr, "ready> ");
1405 #endif
1406   getNextToken();
1407
1408   // Make the helper, which holds all the code.
1409   TheHelper = new MCJITHelper(Context);
1410
1411   // Run the main "interpreter loop" now.
1412   MainLoop();
1413
1414 #ifndef MINIMAL_STDERR_OUTPUT
1415   // Print out all of the generated code.
1416   TheHelper->dump();
1417 #endif
1418
1419   return 0;
1420 }