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

   1 #include "llvm/Analysis/Passes.h"
   2 #include "llvm/ExecutionEngine/ExecutionEngine.h"
   3 #include "llvm/ExecutionEngine/MCJIT.h"
   4 #include "llvm/ExecutionEngine/ObjectCache.h"
   5 #include "llvm/ExecutionEngine/SectionMemoryManager.h"
   6 #include "llvm/IR/DataLayout.h"
   7 #include "llvm/IR/DerivedTypes.h"
   8 #include "llvm/IR/IRBuilder.h"
   9 #include "llvm/IR/LLVMContext.h"
  10 #include "llvm/IR/LegacyPassManager.h"
  11 #include "llvm/IR/Module.h"
  12 #include "llvm/IR/Verifier.h"
  13 #include "llvm/IRReader/IRReader.h"
  14 #include "llvm/Support/CommandLine.h"
  15 #include "llvm/Support/FileSystem.h"
  16 #include "llvm/Support/Path.h"
  17 #include "llvm/Support/SourceMgr.h"
  18 #include "llvm/Support/TargetSelect.h"
  19 #include "llvm/Support/raw_ostream.h"
  20 #include "llvm/Transforms/Scalar.h"
  21 #include <cctype>
  22 #include <cstdio>
  23 #include <map>
  24 #include <string>
  25 #include <vector>
  26
  27 using namespace llvm;
  28
  29 //===----------------------------------------------------------------------===//
  30 // Command-line options
  31 //===----------------------------------------------------------------------===//
  32
  33 namespace {
  34   cl::opt<std::string>
  35   InputIR("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
  39   cl::opt<bool>
  40   VerboseOutput("verbose",
  41                 cl::desc("Enable verbose output (results, IR, etc.) to stderr"),
  42                 cl::init(false));
  43
  44   cl::opt<bool>
  45   SuppressPrompts("suppress-prompts",
  46                   cl::desc("Disable printing the 'ready' prompt"),
  47                   cl::init(false));
  48
  49   cl::opt<bool>
  50   DumpModulesOnExit("dump-modules",
  51                   cl::desc("Dump IR from modules to stderr on shutdown"),
  52                   cl::init(false));
  53
  54   cl::opt<bool> EnableLazyCompilation(
  55     "enable-lazy-compilation", cl::desc("Enable lazy compilation when using the MCJIT engine"),
  56     cl::init(true));
  57
  58   cl::opt<bool> UseObjectCache(
  59     "use-object-cache", cl::desc("Enable use of the MCJIT object caching"),
  60     cl::init(false));
  61 } // namespace
  62
  63 //===----------------------------------------------------------------------===//
  64 // Lexer
  65 //===----------------------------------------------------------------------===//
  66
  67 // The lexer returns tokens [0-255] if it is an unknown character, otherwise one
  68 // of these for known things.
  69 enum Token {
  70   tok_eof = -1,
  71
  72   // commands
  73   tok_def = -2, tok_extern = -3,
  74
  75   // primary
  76   tok_identifier = -4, tok_number = -5,
  77
  78   // control
  79   tok_if = -6, tok_then = -7, tok_else = -8,
  80   tok_for = -9, tok_in = -10,
  81
  82   // operators
  83   tok_binary = -11, tok_unary = -12,
  84
  85   // var definition
  86   tok_var = -13
  87 };
  88
  89 static std::string IdentifierStr;  // Filled in if tok_identifier
  90 static double NumVal;              // Filled in if tok_number
  91
  92 /// gettok - Return the next token from standard input.
  93 static int gettok() {
  94   static int LastChar = ' ';
  95
  96   // Skip any whitespace.
  97   while (isspace(LastChar))
  98     LastChar = getchar();
  99
 100   if (isalpha(LastChar)) { // identifier: [a-zA-Z][a-zA-Z0-9]*
 101     IdentifierStr = LastChar;
 102     while (isalnum((LastChar = getchar())))
 103       IdentifierStr += LastChar;
 104
 105     if (IdentifierStr == "def") return tok_def;
 106     if (IdentifierStr == "extern") return tok_extern;
 107     if (IdentifierStr == "if") return tok_if;
 108     if (IdentifierStr == "then") return tok_then;
 109     if (IdentifierStr == "else") return tok_else;
 110     if (IdentifierStr == "for") return tok_for;
 111     if (IdentifierStr == "in") return tok_in;
 112     if (IdentifierStr == "binary") return tok_binary;
 113     if (IdentifierStr == "unary") return tok_unary;
 114     if (IdentifierStr == "var") return tok_var;
 115     return tok_identifier;
 116   }
 117
 118   if (isdigit(LastChar) || LastChar == '.') {   // Number: [0-9.]+
 119     std::string NumStr;
 120     do {
 121       NumStr += LastChar;
 122       LastChar = getchar();
 123     } while (isdigit(LastChar) || LastChar == '.');
 124
 125     NumVal = strtod(NumStr.c_str(), 0);
 126     return tok_number;
 127   }
 128
 129   if (LastChar == '#') {
 130     // Comment until end of line.
 131     do LastChar = getchar();
 132     while (LastChar != EOF && LastChar != '\n' && LastChar != '\r');
 133
 134     if (LastChar != EOF)
 135       return gettok();
 136   }
 137
 138   // Check for end of file.  Don't eat the EOF.
 139   if (LastChar == EOF)
 140     return tok_eof;
 141
 142   // Otherwise, just return the character as its ascii value.
 143   int ThisChar = LastChar;
 144   LastChar = getchar();
 145   return ThisChar;
 146 }
 147
 148 //===----------------------------------------------------------------------===//
 149 // Abstract Syntax Tree (aka Parse Tree)
 150 //===----------------------------------------------------------------------===//
 151
 152 /// ExprAST - Base class for all expression nodes.
 153 class ExprAST {
 154 public:
 155   virtual ~ExprAST() {}
 156   virtual Value *Codegen() = 0;
 157 };
 158
 159 /// NumberExprAST - Expression class for numeric literals like "1.0".
 160 class NumberExprAST : public ExprAST {
 161   double Val;
 162 public:
 163   NumberExprAST(double val) : Val(val) {}
 164   virtual Value *Codegen();
 165 };
 166
 167 /// VariableExprAST - Expression class for referencing a variable, like "a".
 168 class VariableExprAST : public ExprAST {
 169   std::string Name;
 170 public:
 171   VariableExprAST(const std::string &name) : Name(name) {}
 172   const std::string &getName() const { return Name; }
 173   virtual Value *Codegen();
 174 };
 175
 176 /// UnaryExprAST - Expression class for a unary operator.
 177 class UnaryExprAST : public ExprAST {
 178   char Opcode;
 179   ExprAST *Operand;
 180 public:
 181   UnaryExprAST(char opcode, ExprAST *operand)
 182     : Opcode(opcode), Operand(operand) {}
 183   virtual Value *Codegen();
 184 };
 185
 186 /// BinaryExprAST - Expression class for a binary operator.
 187 class BinaryExprAST : public ExprAST {
 188   char Op;
 189   ExprAST *LHS, *RHS;
 190 public:
 191   BinaryExprAST(char op, ExprAST *lhs, ExprAST *rhs)
 192     : Op(op), LHS(lhs), RHS(rhs) {}
 193   virtual Value *Codegen();
 194 };
 195
 196 /// CallExprAST - Expression class for function calls.
 197 class CallExprAST : public ExprAST {
 198   std::string Callee;
 199   std::vector<ExprAST*> Args;
 200 public:
 201   CallExprAST(const std::string &callee, std::vector<ExprAST*> &args)
 202     : Callee(callee), Args(args) {}
 203   virtual Value *Codegen();
 204 };
 205
 206 /// IfExprAST - Expression class for if/then/else.
 207 class IfExprAST : public ExprAST {
 208   ExprAST *Cond, *Then, *Else;
 209 public:
 210   IfExprAST(ExprAST *cond, ExprAST *then, ExprAST *_else)
 211   : Cond(cond), Then(then), Else(_else) {}
 212   virtual Value *Codegen();
 213 };
 214
 215 /// ForExprAST - Expression class for for/in.
 216 class ForExprAST : public ExprAST {
 217   std::string VarName;
 218   ExprAST *Start, *End, *Step, *Body;
 219 public:
 220   ForExprAST(const std::string &varname, ExprAST *start, ExprAST *end,
 221              ExprAST *step, ExprAST *body)
 222     : VarName(varname), Start(start), End(end), Step(step), Body(body) {}
 223   virtual Value *Codegen();
 224 };
 225
 226 /// VarExprAST - Expression class for var/in
 227 class VarExprAST : public ExprAST {
 228   std::vector<std::pair<std::string, ExprAST*> > VarNames;
 229   ExprAST *Body;
 230 public:
 231   VarExprAST(const std::vector<std::pair<std::string, ExprAST*> > &varnames,
 232              ExprAST *body)
 233   : VarNames(varnames), Body(body) {}
 234
 235   virtual Value *Codegen();
 236 };
 237
 238 /// PrototypeAST - This class represents the "prototype" for a function,
 239 /// which captures its argument names as well as if it is an operator.
 240 class PrototypeAST {
 241   std::string Name;
 242   std::vector<std::string> Args;
 243   bool isOperator;
 244   unsigned Precedence;  // Precedence if a binary op.
 245 public:
 246   PrototypeAST(const std::string &name, const std::vector<std::string> &args,
 247                bool isoperator = false, unsigned prec = 0)
 248   : Name(name), Args(args), isOperator(isoperator), Precedence(prec) {}
 249
 250   bool isUnaryOp() const { return isOperator && Args.size() == 1; }
 251   bool isBinaryOp() const { return isOperator && Args.size() == 2; }
 252
 253   char getOperatorName() const {
 254     assert(isUnaryOp() || isBinaryOp());
 255     return Name[Name.size()-1];
 256   }
 257
 258   unsigned getBinaryPrecedence() const { return Precedence; }
 259
 260   Function *Codegen();
 261
 262   void CreateArgumentAllocas(Function *F);
 263 };
 264
 265 /// FunctionAST - This class represents a function definition itself.
 266 class FunctionAST {
 267   PrototypeAST *Proto;
 268   ExprAST *Body;
 269 public:
 270   FunctionAST(PrototypeAST *proto, ExprAST *body)
 271     : Proto(proto), Body(body) {}
 272
 273   Function *Codegen();
 274 };
 275
 276 //===----------------------------------------------------------------------===//
 277 // Parser
 278 //===----------------------------------------------------------------------===//
 279
 280 /// CurTok/getNextToken - Provide a simple token buffer.  CurTok is the current
 281 /// token the parser is looking at.  getNextToken reads another token from the
 282 /// lexer and updates CurTok with its results.
 283 static int CurTok;
 284 static int getNextToken() {
 285   return CurTok = gettok();
 286 }
 287
 288 /// BinopPrecedence - This holds the precedence for each binary operator that is
 289 /// defined.
 290 static std::map<char, int> BinopPrecedence;
 291
 292 /// GetTokPrecedence - Get the precedence of the pending binary operator token.
 293 static int GetTokPrecedence() {
 294   if (!isascii(CurTok))
 295     return -1;
 296
 297   // Make sure it's a declared binop.
 298   int TokPrec = BinopPrecedence[CurTok];
 299   if (TokPrec <= 0) return -1;
 300   return TokPrec;
 301 }
 302
 303 /// Error* - These are little helper functions for error handling.
 304 ExprAST *Error(const char *Str) { fprintf(stderr, "Error: %s\n", Str);return 0;}
 305 PrototypeAST *ErrorP(const char *Str) { Error(Str); return 0; }
 306 FunctionAST *ErrorF(const char *Str) { Error(Str); return 0; }
 307
 308 static ExprAST *ParseExpression();
 309
 310 /// identifierexpr
 311 ///   ::= identifier
 312 ///   ::= identifier '(' expression* ')'
 313 static ExprAST *ParseIdentifierExpr() {
 314   std::string IdName = IdentifierStr;
 315
 316   getNextToken();  // eat identifier.
 317
 318   if (CurTok != '(') // Simple variable ref.
 319     return new VariableExprAST(IdName);
 320
 321   // Call.
 322   getNextToken();  // eat (
 323   std::vector<ExprAST*> Args;
 324   if (CurTok != ')') {
 325     while (1) {
 326       ExprAST *Arg = ParseExpression();
 327       if (!Arg) return 0;
 328       Args.push_back(Arg);
 329
 330       if (CurTok == ')') break;
 331
 332       if (CurTok != ',')
 333         return Error("Expected ')' or ',' in argument list");
 334       getNextToken();
 335     }
 336   }
 337
 338   // Eat the ')'.
 339   getNextToken();
 340
 341   return new CallExprAST(IdName, Args);
 342 }
 343
 344 /// numberexpr ::= number
 345 static ExprAST *ParseNumberExpr() {
 346   ExprAST *Result = new NumberExprAST(NumVal);
 347   getNextToken(); // consume the number
 348   return Result;
 349 }
 350
 351 /// parenexpr ::= '(' expression ')'
 352 static ExprAST *ParseParenExpr() {
 353   getNextToken();  // eat (.
 354   ExprAST *V = ParseExpression();
 355   if (!V) return 0;
 356
 357   if (CurTok != ')')
 358     return Error("expected ')'");
 359   getNextToken();  // eat ).
 360   return V;
 361 }
 362
 363 /// ifexpr ::= 'if' expression 'then' expression 'else' expression
 364 static ExprAST *ParseIfExpr() {
 365   getNextToken();  // eat the if.
 366
 367   // condition.
 368   ExprAST *Cond = ParseExpression();
 369   if (!Cond) return 0;
 370
 371   if (CurTok != tok_then)
 372     return Error("expected then");
 373   getNextToken();  // eat the then
 374
 375   ExprAST *Then = ParseExpression();
 376   if (Then == 0) return 0;
 377
 378   if (CurTok != tok_else)
 379     return Error("expected else");
 380
 381   getNextToken();
 382
 383   ExprAST *Else = ParseExpression();
 384   if (!Else) return 0;
 385
 386   return new IfExprAST(Cond, Then, Else);
 387 }
 388
 389 /// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression
 390 static ExprAST *ParseForExpr() {
 391   getNextToken();  // eat the for.
 392
 393   if (CurTok != tok_identifier)
 394     return Error("expected identifier after for");
 395
 396   std::string IdName = IdentifierStr;
 397   getNextToken();  // eat identifier.
 398
 399   if (CurTok != '=')
 400     return Error("expected '=' after for");
 401   getNextToken();  // eat '='.
 402
 403
 404   ExprAST *Start = ParseExpression();
 405   if (Start == 0) return 0;
 406   if (CurTok != ',')
 407     return Error("expected ',' after for start value");
 408   getNextToken();
 409
 410   ExprAST *End = ParseExpression();
 411   if (End == 0) return 0;
 412
 413   // The step value is optional.
 414   ExprAST *Step = 0;
 415   if (CurTok == ',') {
 416     getNextToken();
 417     Step = ParseExpression();
 418     if (Step == 0) return 0;
 419   }
 420
 421   if (CurTok != tok_in)
 422     return Error("expected 'in' after for");
 423   getNextToken();  // eat 'in'.
 424
 425   ExprAST *Body = ParseExpression();
 426   if (Body == 0) return 0;
 427
 428   return new ForExprAST(IdName, Start, End, Step, Body);
 429 }
 430
 431 /// varexpr ::= 'var' identifier ('=' expression)?
 432 //                    (',' identifier ('=' expression)?)* 'in' expression
 433 static ExprAST *ParseVarExpr() {
 434   getNextToken();  // eat the var.
 435
 436   std::vector<std::pair<std::string, ExprAST*> > VarNames;
 437
 438   // At least one variable name is required.
 439   if (CurTok != tok_identifier)
 440     return Error("expected identifier after var");
 441
 442   while (1) {
 443     std::string Name = IdentifierStr;
 444     getNextToken();  // eat identifier.
 445
 446     // Read the optional initializer.
 447     ExprAST *Init = 0;
 448     if (CurTok == '=') {
 449       getNextToken(); // eat the '='.
 450
 451       Init = ParseExpression();
 452       if (Init == 0) return 0;
 453     }
 454
 455     VarNames.push_back(std::make_pair(Name, Init));
 456
 457     // End of var list, exit loop.
 458     if (CurTok != ',') break;
 459     getNextToken(); // eat the ','.
 460
 461     if (CurTok != tok_identifier)
 462       return Error("expected identifier list after var");
 463   }
 464
 465   // At this point, we have to have 'in'.
 466   if (CurTok != tok_in)
 467     return Error("expected 'in' keyword after 'var'");
 468   getNextToken();  // eat 'in'.
 469
 470   ExprAST *Body = ParseExpression();
 471   if (Body == 0) return 0;
 472
 473   return new VarExprAST(VarNames, Body);
 474 }
 475
 476 /// primary
 477 ///   ::= identifierexpr
 478 ///   ::= numberexpr
 479 ///   ::= parenexpr
 480 ///   ::= ifexpr
 481 ///   ::= forexpr
 482 ///   ::= varexpr
 483 static ExprAST *ParsePrimary() {
 484   switch (CurTok) {
 485   default: return Error("unknown token when expecting an expression");
 486   case tok_identifier: return ParseIdentifierExpr();
 487   case tok_number:     return ParseNumberExpr();
 488   case '(':            return ParseParenExpr();
 489   case tok_if:         return ParseIfExpr();
 490   case tok_for:        return ParseForExpr();
 491   case tok_var:        return ParseVarExpr();
 492   }
 493 }
 494
 495 /// unary
 496 ///   ::= primary
 497 ///   ::= '!' unary
 498 static ExprAST *ParseUnary() {
 499   // If the current token is not an operator, it must be a primary expr.
 500   if (!isascii(CurTok) || CurTok == '(' || CurTok == ',')
 501     return ParsePrimary();
 502
 503   // If this is a unary operator, read it.
 504   int Opc = CurTok;
 505   getNextToken();
 506   if (ExprAST *Operand = ParseUnary())
 507     return new UnaryExprAST(Opc, Operand);
 508   return 0;
 509 }
 510
 511 /// binoprhs
 512 ///   ::= ('+' unary)*
 513 static ExprAST *ParseBinOpRHS(int ExprPrec, ExprAST *LHS) {
 514   // If this is a binop, find its precedence.
 515   while (1) {
 516     int TokPrec = GetTokPrecedence();
 517
 518     // If this is a binop that binds at least as tightly as the current binop,
 519     // consume it, otherwise we are done.
 520     if (TokPrec < ExprPrec)
 521       return LHS;
 522
 523     // Okay, we know this is a binop.
 524     int BinOp = CurTok;
 525     getNextToken();  // eat binop
 526
 527     // Parse the unary expression after the binary operator.
 528     ExprAST *RHS = ParseUnary();
 529     if (!RHS) return 0;
 530
 531     // If BinOp binds less tightly with RHS than the operator after RHS, let
 532     // the pending operator take RHS as its LHS.
 533     int NextPrec = GetTokPrecedence();
 534     if (TokPrec < NextPrec) {
 535       RHS = ParseBinOpRHS(TokPrec+1, RHS);
 536       if (RHS == 0) return 0;
 537     }
 538
 539     // Merge LHS/RHS.
 540     LHS = new BinaryExprAST(BinOp, LHS, RHS);
 541   }
 542 }
 543
 544 /// expression
 545 ///   ::= unary binoprhs
 546 ///
 547 static ExprAST *ParseExpression() {
 548   ExprAST *LHS = ParseUnary();
 549   if (!LHS) return 0;
 550
 551   return ParseBinOpRHS(0, LHS);
 552 }
 553
 554 /// prototype
 555 ///   ::= id '(' id* ')'
 556 ///   ::= binary LETTER number? (id, id)
 557 ///   ::= unary LETTER (id)
 558 static PrototypeAST *ParsePrototype() {
 559   std::string FnName;
 560
 561   unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.
 562   unsigned BinaryPrecedence = 30;
 563
 564   switch (CurTok) {
 565   default:
 566     return ErrorP("Expected function name in prototype");
 567   case tok_identifier:
 568     FnName = IdentifierStr;
 569     Kind = 0;
 570     getNextToken();
 571     break;
 572   case tok_unary:
 573     getNextToken();
 574     if (!isascii(CurTok))
 575       return ErrorP("Expected unary operator");
 576     FnName = "unary";
 577     FnName += (char)CurTok;
 578     Kind = 1;
 579     getNextToken();
 580     break;
 581   case tok_binary:
 582     getNextToken();
 583     if (!isascii(CurTok))
 584       return ErrorP("Expected binary operator");
 585     FnName = "binary";
 586     FnName += (char)CurTok;
 587     Kind = 2;
 588     getNextToken();
 589
 590     // Read the precedence if present.
 591     if (CurTok == tok_number) {
 592       if (NumVal < 1 || NumVal > 100)
 593         return ErrorP("Invalid precedecnce: must be 1..100");
 594       BinaryPrecedence = (unsigned)NumVal;
 595       getNextToken();
 596     }
 597     break;
 598   }
 599
 600   if (CurTok != '(')
 601     return ErrorP("Expected '(' in prototype");
 602
 603   std::vector<std::string> ArgNames;
 604   while (getNextToken() == tok_identifier)
 605     ArgNames.push_back(IdentifierStr);
 606   if (CurTok != ')')
 607     return ErrorP("Expected ')' in prototype");
 608
 609   // success.
 610   getNextToken();  // eat ')'.
 611
 612   // Verify right number of names for operator.
 613   if (Kind && ArgNames.size() != Kind)
 614     return ErrorP("Invalid number of operands for operator");
 615
 616   return new PrototypeAST(FnName, ArgNames, Kind != 0, BinaryPrecedence);
 617 }
 618
 619 /// definition ::= 'def' prototype expression
 620 static FunctionAST *ParseDefinition() {
 621   getNextToken();  // eat def.
 622   PrototypeAST *Proto = ParsePrototype();
 623   if (Proto == 0) return 0;
 624
 625   if (ExprAST *E = ParseExpression())
 626     return new FunctionAST(Proto, E);
 627   return 0;
 628 }
 629
 630 /// toplevelexpr ::= expression
 631 static FunctionAST *ParseTopLevelExpr() {
 632   if (ExprAST *E = ParseExpression()) {
 633     // Make an anonymous proto.
 634     PrototypeAST *Proto = new PrototypeAST("", std::vector<std::string>());
 635     return new FunctionAST(Proto, E);
 636   }
 637   return 0;
 638 }
 639
 640 /// external ::= 'extern' prototype
 641 static PrototypeAST *ParseExtern() {
 642   getNextToken();  // eat extern.
 643   return ParsePrototype();
 644 }
 645
 646 //===----------------------------------------------------------------------===//
 647 // Quick and dirty hack
 648 //===----------------------------------------------------------------------===//
 649
 650 // FIXME: Obviously we can do better than this
 651 std::string GenerateUniqueName(const char *root)
 652 {
 653   static int i = 0;
 654   char s[16];
 655   sprintf(s, "%s%d", root, i++);
 656   std::string S = s;
 657   return S;
 658 }
 659
 660 std::string MakeLegalFunctionName(std::string Name)
 661 {
 662   std::string NewName;
 663   if (!Name.length())
 664       return GenerateUniqueName("anon_func_");
 665
 666   // Start with what we have
 667   NewName = Name;
 668
 669   // Look for a numberic first character
 670   if (NewName.find_first_of("0123456789") == 0) {
 671     NewName.insert(0, 1, 'n');
 672   }
 673
 674   // Replace illegal characters with their ASCII equivalent
 675   std::string legal_elements = "_abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
 676   size_t pos;
 677   while ((pos = NewName.find_first_not_of(legal_elements)) != std::string::npos) {
 678     char old_c = NewName.at(pos);
 679     char new_str[16];
 680     sprintf(new_str, "%d", (int)old_c);
 681     NewName = NewName.replace(pos, 1, new_str);
 682   }
 683
 684   return NewName;
 685 }
 686
 687 //===----------------------------------------------------------------------===//
 688 // MCJIT object cache class
 689 //===----------------------------------------------------------------------===//
 690
 691 class MCJITObjectCache : public ObjectCache {
 692 public:
 693   MCJITObjectCache() {
 694     // Set IR cache directory
 695     sys::fs::current_path(CacheDir);
 696     sys::path::append(CacheDir, "toy_object_cache");
 697   }
 698
 699   virtual ~MCJITObjectCache() {
 700   }
 701
 702   virtual void notifyObjectCompiled(const Module *M, const MemoryBuffer *Obj) {
 703     // Get the ModuleID
 704     const std::string ModuleID = M->getModuleIdentifier();
 705
 706     // If we've flagged this as an IR file, cache it
 707     if (0 == ModuleID.compare(0, 3, "IR:")) {
 708       std::string IRFileName = ModuleID.substr(3);
 709       SmallString<128>IRCacheFile = CacheDir;
 710       sys::path::append(IRCacheFile, IRFileName);
 711       if (!sys::fs::exists(CacheDir.str()) && sys::fs::create_directory(CacheDir.str())) {
 712         fprintf(stderr, "Unable to create cache directory\n");
 713         return;
 714       }
 715       std::string ErrStr;
 716       raw_fd_ostream IRObjectFile(IRCacheFile.c_str(), ErrStr, raw_fd_ostream::F_Binary);
 717       IRObjectFile << Obj->getBuffer();
 718     }
 719   }
 720
 721   // MCJIT will call this function before compiling any module
 722   // MCJIT takes ownership of both the MemoryBuffer object and the memory
 723   // to which it refers.
 724   virtual MemoryBuffer* getObject(const Module* M) {
 725     // Get the ModuleID
 726     const std::string ModuleID = M->getModuleIdentifier();
 727
 728     // If we've flagged this as an IR file, cache it
 729     if (0 == ModuleID.compare(0, 3, "IR:")) {
 730       std::string IRFileName = ModuleID.substr(3);
 731       SmallString<128> IRCacheFile = CacheDir;
 732       sys::path::append(IRCacheFile, IRFileName);
 733       if (!sys::fs::exists(IRCacheFile.str())) {
 734         // This file isn't in our cache
 735         return NULL;
 736       }
 737       std::unique_ptr<MemoryBuffer> IRObjectBuffer;
 738       MemoryBuffer::getFile(IRCacheFile.c_str(), IRObjectBuffer, -1, false);
 739       // MCJIT will want to write into this buffer, and we don't want that
 740       // because the file has probably just been mmapped.  Instead we make
 741       // a copy.  The filed-based buffer will be released when it goes
 742       // out of scope.
 743       return MemoryBuffer::getMemBufferCopy(IRObjectBuffer->getBuffer());
 744     }
 745
 746     return NULL;
 747   }
 748
 749 private:
 750   SmallString<128> CacheDir;
 751 };
 752
 753 //===----------------------------------------------------------------------===//
 754 // IR input file handler
 755 //===----------------------------------------------------------------------===//
 756
 757 Module* parseInputIR(std::string InputFile, LLVMContext &Context) {
 758   SMDiagnostic Err;
 759   Module *M = ParseIRFile(InputFile, Err, Context);
 760   if (!M) {
 761     Err.print("IR parsing failed: ", errs());
 762     return NULL;
 763   }
 764
 765   char ModID[256];
 766   sprintf(ModID, "IR:%s", InputFile.c_str());
 767   M->setModuleIdentifier(ModID);
 768   return M;
 769 }
 770
 771 //===----------------------------------------------------------------------===//
 772 // Helper class for execution engine abstraction
 773 //===----------------------------------------------------------------------===//
 774
 775 class BaseHelper
 776 {
 777 public:
 778   BaseHelper() {}
 779   virtual ~BaseHelper() {}
 780
 781   virtual Function *getFunction(const std::string FnName) = 0;
 782   virtual Module *getModuleForNewFunction() = 0;
 783   virtual void *getPointerToFunction(Function* F) = 0;
 784   virtual void *getPointerToNamedFunction(const std::string &Name) = 0;
 785   virtual void closeCurrentModule() = 0;
 786   virtual void runFPM(Function &F) = 0;
 787   virtual void dump();
 788 };
 789
 790 //===----------------------------------------------------------------------===//
 791 // MCJIT helper class
 792 //===----------------------------------------------------------------------===//
 793
 794 class MCJITHelper : public BaseHelper
 795 {
 796 public:
 797   MCJITHelper(LLVMContext& C) : Context(C), CurrentModule(NULL) {
 798     if (!InputIR.empty()) {
 799       Module *M = parseInputIR(InputIR, Context);
 800       Modules.push_back(M);
 801       if (!EnableLazyCompilation)
 802         compileModule(M);
 803     }
 804   }
 805   ~MCJITHelper();
 806
 807   Function *getFunction(const std::string FnName);
 808   Module *getModuleForNewFunction();
 809   void *getPointerToFunction(Function* F);
 810   void *getPointerToNamedFunction(const std::string &Name);
 811   void closeCurrentModule();
 812   virtual void runFPM(Function &F) {} // Not needed, see compileModule
 813   void dump();
 814
 815 protected:
 816   ExecutionEngine *compileModule(Module *M);
 817
 818 private:
 819   typedef std::vector<Module*> ModuleVector;
 820
 821   MCJITObjectCache OurObjectCache;
 822
 823   LLVMContext  &Context;
 824   ModuleVector  Modules;
 825
 826   std::map<Module *, ExecutionEngine *> EngineMap;
 827
 828   Module       *CurrentModule;
 829 };
 830
 831 class HelpingMemoryManager : public SectionMemoryManager
 832 {
 833   HelpingMemoryManager(const HelpingMemoryManager&) = delete;
 834   void operator=(const HelpingMemoryManager&) = delete;
 835
 836 public:
 837   HelpingMemoryManager(MCJITHelper *Helper) : MasterHelper(Helper) {}
 838   virtual ~HelpingMemoryManager() {}
 839
 840   /// This method returns the address of the specified function.
 841   /// Our implementation will attempt to find functions in other
 842   /// modules associated with the MCJITHelper to cross link functions
 843   /// from one generated module to another.
 844   ///
 845   /// If \p AbortOnFailure is false and no function with the given name is
 846   /// found, this function returns a null pointer. Otherwise, it prints a
 847   /// message to stderr and aborts.
 848   virtual void *getPointerToNamedFunction(const std::string &Name,
 849                                           bool AbortOnFailure = true);
 850 private:
 851   MCJITHelper *MasterHelper;
 852 };
 853
 854 void *HelpingMemoryManager::getPointerToNamedFunction(const std::string &Name,
 855                                         bool AbortOnFailure)
 856 {
 857   // Try the standard symbol resolution first, but ask it not to abort.
 858   void *pfn = RTDyldMemoryManager::getPointerToNamedFunction(Name, false);
 859   if (pfn)
 860     return pfn;
 861
 862   pfn = MasterHelper->getPointerToNamedFunction(Name);
 863   if (!pfn && AbortOnFailure)
 864     report_fatal_error("Program used external function '" + Name +
 865                         "' which could not be resolved!");
 866   return pfn;
 867 }
 868
 869 MCJITHelper::~MCJITHelper()
 870 {
 871   // Walk the vector of modules.
 872   ModuleVector::iterator it, end;
 873   for (it = Modules.begin(), end = Modules.end();
 874        it != end; ++it) {
 875     // See if we have an execution engine for this module.
 876     std::map<Module*, ExecutionEngine*>::iterator mapIt = EngineMap.find(*it);
 877     // If we have an EE, the EE owns the module so just delete the EE.
 878     if (mapIt != EngineMap.end()) {
 879       delete mapIt->second;
 880     } else {
 881       // Otherwise, we still own the module.  Delete it now.
 882       delete *it;
 883     }
 884   }
 885 }
 886
 887 Function *MCJITHelper::getFunction(const std::string FnName) {
 888   ModuleVector::iterator begin = Modules.begin();
 889   ModuleVector::iterator end = Modules.end();
 890   ModuleVector::iterator it;
 891   for (it = begin; it != end; ++it) {
 892     Function *F = (*it)->getFunction(FnName);
 893     if (F) {
 894       if (*it == CurrentModule)
 895           return F;
 896
 897       assert(CurrentModule != NULL);
 898
 899       // This function is in a module that has already been JITed.
 900       // We just need a prototype for external linkage.
 901       Function *PF = CurrentModule->getFunction(FnName);
 902       if (PF && !PF->empty()) {
 903         ErrorF("redefinition of function across modules");
 904         return 0;
 905       }
 906
 907       // If we don't have a prototype yet, create one.
 908       if (!PF)
 909         PF = Function::Create(F->getFunctionType(),
 910                                       Function::ExternalLinkage,
 911                                       FnName,
 912                                       CurrentModule);
 913       return PF;
 914     }
 915   }
 916   return NULL;
 917 }
 918
 919 Module *MCJITHelper::getModuleForNewFunction() {
 920   // If we have a Module that hasn't been JITed, use that.
 921   if (CurrentModule)
 922     return CurrentModule;
 923
 924   // Otherwise create a new Module.
 925   std::string ModName = GenerateUniqueName("mcjit_module_");
 926   Module *M = new Module(ModName, Context);
 927   Modules.push_back(M);
 928   CurrentModule = M;
 929
 930   return M;
 931 }
 932
 933 ExecutionEngine *MCJITHelper::compileModule(Module *M) {
 934   assert(EngineMap.find(M) == EngineMap.end());
 935
 936   if (M == CurrentModule)
 937     closeCurrentModule();
 938
 939   std::string ErrStr;
 940   ExecutionEngine *EE = EngineBuilder(M)
 941                             .setErrorStr(&ErrStr)
 942                             .setMCJITMemoryManager(new HelpingMemoryManager(this))
 943                             .create();
 944   if (!EE) {
 945     fprintf(stderr, "Could not create ExecutionEngine: %s\n", ErrStr.c_str());
 946     exit(1);
 947   }
 948
 949   if (UseObjectCache)
 950     EE->setObjectCache(&OurObjectCache);
 951   // Get the ModuleID so we can identify IR input files
 952   const std::string ModuleID = M->getModuleIdentifier();
 953
 954   // If we've flagged this as an IR file, it doesn't need function passes run.
 955   if (0 != ModuleID.compare(0, 3, "IR:")) {
 956     FunctionPassManager *FPM = 0;
 957
 958     // Create a FPM for this module
 959     FPM = new FunctionPassManager(M);
 960
 961     // Set up the optimizer pipeline.  Start with registering info about how the
 962     // target lays out data structures.
 963     FPM->add(new DataLayout(*EE->getDataLayout()));
 964     // Provide basic AliasAnalysis support for GVN.
 965     FPM->add(createBasicAliasAnalysisPass());
 966     // Promote allocas to registers.
 967     FPM->add(createPromoteMemoryToRegisterPass());
 968     // Do simple "peephole" optimizations and bit-twiddling optzns.
 969     FPM->add(createInstructionCombiningPass());
 970     // Reassociate expressions.
 971     FPM->add(createReassociatePass());
 972     // Eliminate Common SubExpressions.
 973     FPM->add(createGVNPass());
 974     // Simplify the control flow graph (deleting unreachable blocks, etc).
 975     FPM->add(createCFGSimplificationPass());
 976
 977     FPM->doInitialization();
 978
 979     // For each function in the module
 980     Module::iterator it;
 981     Module::iterator end = M->end();
 982     for (it = M->begin(); it != end; ++it) {
 983       // Run the FPM on this function
 984       FPM->run(*it);
 985     }
 986
 987     delete FPM;
 988   }
 989
 990   EE->finalizeObject();
 991
 992   // Store this engine
 993   EngineMap[M] = EE;
 994
 995   return EE;
 996 }
 997
 998 void *MCJITHelper::getPointerToFunction(Function* F) {
 999   // Look for this function in an existing module
1000   ModuleVector::iterator begin = Modules.begin();
1001   ModuleVector::iterator end = Modules.end();
1002   ModuleVector::iterator it;
1003   std::string FnName = F->getName();
1004   for (it = begin; it != end; ++it) {
1005     Function *MF = (*it)->getFunction(FnName);
1006     if (MF == F) {
1007       std::map<Module*, ExecutionEngine*>::iterator eeIt = EngineMap.find(*it);
1008       if (eeIt != EngineMap.end()) {
1009         void *P = eeIt->second->getPointerToFunction(F);
1010         if (P)
1011           return P;
1012       } else {
1013         ExecutionEngine *EE = compileModule(*it);
1014         void *P = EE->getPointerToFunction(F);
1015         if (P)
1016           return P;
1017       }
1018     }
1019   }
1020   return NULL;
1021 }
1022
1023 void MCJITHelper::closeCurrentModule() {
1024     // If we have an open module (and we should), pack it up
1025   if (CurrentModule) {
1026     CurrentModule = NULL;
1027   }
1028 }
1029
1030 void *MCJITHelper::getPointerToNamedFunction(const std::string &Name)
1031 {
1032   // Look for the functions in our modules, compiling only as necessary
1033   ModuleVector::iterator begin = Modules.begin();
1034   ModuleVector::iterator end = Modules.end();
1035   ModuleVector::iterator it;
1036   for (it = begin; it != end; ++it) {
1037     Function *F = (*it)->getFunction(Name);
1038     if (F && !F->empty()) {
1039       std::map<Module*, ExecutionEngine*>::iterator eeIt = EngineMap.find(*it);
1040       if (eeIt != EngineMap.end()) {
1041         void *P = eeIt->second->getPointerToFunction(F);
1042         if (P)
1043           return P;
1044       } else {
1045         ExecutionEngine *EE = compileModule(*it);
1046         void *P = EE->getPointerToFunction(F);
1047         if (P)
1048           return P;
1049       }
1050     }
1051   }
1052   return NULL;
1053 }
1054
1055 void MCJITHelper::dump()
1056 {
1057   ModuleVector::iterator begin = Modules.begin();
1058   ModuleVector::iterator end = Modules.end();
1059   ModuleVector::iterator it;
1060   for (it = begin; it != end; ++it)
1061     (*it)->dump();
1062 }
1063
1064 //===----------------------------------------------------------------------===//
1065 // Code Generation
1066 //===----------------------------------------------------------------------===//
1067
1068 static BaseHelper *TheHelper;
1069 static LLVMContext TheContext;
1070 static IRBuilder<> Builder(TheContext);
1071 static std::map<std::string, AllocaInst*> NamedValues;
1072
1073 Value *ErrorV(const char *Str) { Error(Str); return 0; }
1074
1075 /// CreateEntryBlockAlloca - Create an alloca instruction in the entry block of
1076 /// the function.  This is used for mutable variables etc.
1077 static AllocaInst *CreateEntryBlockAlloca(Function *TheFunction,
1078                                           const std::string &VarName) {
1079   IRBuilder<> TmpB(&TheFunction->getEntryBlock(),
1080                  TheFunction->getEntryBlock().begin());
1081   return TmpB.CreateAlloca(Type::getDoubleTy(TheContext), 0, VarName.c_str());
1082 }
1083
1084 Value *NumberExprAST::Codegen() {
1085   return ConstantFP::get(TheContext, APFloat(Val));
1086 }
1087
1088 Value *VariableExprAST::Codegen() {
1089   // Look this variable up in the function.
1090   Value *V = NamedValues[Name];
1091   if (V == 0) return ErrorV("Unknown variable name");
1092
1093   // Load the value.
1094   return Builder.CreateLoad(V, Name.c_str());
1095 }
1096
1097 Value *UnaryExprAST::Codegen() {
1098   Value *OperandV = Operand->Codegen();
1099   if (OperandV == 0) return 0;
1100   Function *F;
1101   F = TheHelper->getFunction(
1102       MakeLegalFunctionName(std::string("unary") + Opcode));
1103   if (F == 0)
1104     return ErrorV("Unknown unary operator");
1105
1106   return Builder.CreateCall(F, OperandV, "unop");
1107 }
1108
1109 Value *BinaryExprAST::Codegen() {
1110   // Special case '=' because we don't want to emit the LHS as an expression.
1111   if (Op == '=') {
1112     // Assignment requires the LHS to be an identifier.
1113     // This assume we're building without RTTI because LLVM builds that way by
1114     // default.  If you build LLVM with RTTI this can be changed to a
1115     // dynamic_cast for automatic error checking.
1116     VariableExprAST *LHSE = static_cast<VariableExprAST*>(LHS);
1117     if (!LHSE)
1118       return ErrorV("destination of '=' must be a variable");
1119     // Codegen the RHS.
1120     Value *Val = RHS->Codegen();
1121     if (Val == 0) return 0;
1122
1123     // Look up the name.
1124     Value *Variable = NamedValues[LHSE->getName()];
1125     if (Variable == 0) return ErrorV("Unknown variable name");
1126
1127     Builder.CreateStore(Val, Variable);
1128     return Val;
1129   }
1130
1131   Value *L = LHS->Codegen();
1132   Value *R = RHS->Codegen();
1133   if (L == 0 || R == 0) return 0;
1134
1135   switch (Op) {
1136   case '+': return Builder.CreateFAdd(L, R, "addtmp");
1137   case '-': return Builder.CreateFSub(L, R, "subtmp");
1138   case '*': return Builder.CreateFMul(L, R, "multmp");
1139   case '/': return Builder.CreateFDiv(L, R, "divtmp");
1140   case '<':
1141     L = Builder.CreateFCmpULT(L, R, "cmptmp");
1142     // Convert bool 0/1 to double 0.0 or 1.0
1143     return Builder.CreateUIToFP(L, Type::getDoubleTy(TheContext), "booltmp");
1144   default: break;
1145   }
1146
1147   // If it wasn't a builtin binary operator, it must be a user defined one. Emit
1148   // a call to it.
1149   Function *F;
1150   F = TheHelper->getFunction(MakeLegalFunctionName(std::string("binary")+Op));
1151   assert(F && "binary operator not found!");
1152
1153   Value *Ops[] = { L, R };
1154   return Builder.CreateCall(F, Ops, "binop");
1155 }
1156
1157 Value *CallExprAST::Codegen() {
1158   // Look up the name in the global module table.
1159   Function *CalleeF = TheHelper->getFunction(Callee);
1160   if (CalleeF == 0) {
1161     char error_str[64];
1162     sprintf(error_str, "Unknown function referenced %s", Callee.c_str());
1163     return ErrorV(error_str);
1164   }
1165
1166   // If argument mismatch error.
1167   if (CalleeF->arg_size() != Args.size())
1168     return ErrorV("Incorrect # arguments passed");
1169
1170   std::vector<Value*> ArgsV;
1171   for (unsigned i = 0, e = Args.size(); i != e; ++i) {
1172     ArgsV.push_back(Args[i]->Codegen());
1173     if (ArgsV.back() == 0) return 0;
1174   }
1175
1176   return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
1177 }
1178
1179 Value *IfExprAST::Codegen() {
1180   Value *CondV = Cond->Codegen();
1181   if (CondV == 0) return 0;
1182
1183   // Convert condition to a bool by comparing equal to 0.0.
1184   CondV = Builder.CreateFCmpONE(
1185       CondV, ConstantFP::get(TheContext, APFloat(0.0)), "ifcond");
1186
1187   Function *TheFunction = Builder.GetInsertBlock()->getParent();
1188
1189   // Create blocks for the then and else cases.  Insert the 'then' block at the
1190   // end of the function.
1191   BasicBlock *ThenBB = BasicBlock::Create(TheContext, "then", TheFunction);
1192   BasicBlock *ElseBB = BasicBlock::Create(TheContext, "else");
1193   BasicBlock *MergeBB = BasicBlock::Create(TheContext, "ifcont");
1194
1195   Builder.CreateCondBr(CondV, ThenBB, ElseBB);
1196
1197   // Emit then value.
1198   Builder.SetInsertPoint(ThenBB);
1199
1200   Value *ThenV = Then->Codegen();
1201   if (ThenV == 0) return 0;
1202
1203   Builder.CreateBr(MergeBB);
1204   // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
1205   ThenBB = Builder.GetInsertBlock();
1206
1207   // Emit else block.
1208   TheFunction->insert(TheFunction->end(), ElseBB);
1209   Builder.SetInsertPoint(ElseBB);
1210
1211   Value *ElseV = Else->Codegen();
1212   if (ElseV == 0) return 0;
1213
1214   Builder.CreateBr(MergeBB);
1215   // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
1216   ElseBB = Builder.GetInsertBlock();
1217
1218   // Emit merge block.
1219   TheFunction->insert(TheFunction->end(), MergeBB);
1220   Builder.SetInsertPoint(MergeBB);
1221   PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(TheContext), 2, "iftmp");
1222
1223   PN->addIncoming(ThenV, ThenBB);
1224   PN->addIncoming(ElseV, ElseBB);
1225   return PN;
1226 }
1227
1228 Value *ForExprAST::Codegen() {
1229   // Output this as:
1230   //   var = alloca double
1231   //   ...
1232   //   start = startexpr
1233   //   store start -> var
1234   //   goto loop
1235   // loop:
1236   //   ...
1237   //   bodyexpr
1238   //   ...
1239   // loopend:
1240   //   step = stepexpr
1241   //   endcond = endexpr
1242   //
1243   //   curvar = load var
1244   //   nextvar = curvar + step
1245   //   store nextvar -> var
1246   //   br endcond, loop, endloop
1247   // outloop:
1248
1249   Function *TheFunction = Builder.GetInsertBlock()->getParent();
1250
1251   // Create an alloca for the variable in the entry block.
1252   AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
1253
1254   // Emit the start code first, without 'variable' in scope.
1255   Value *StartVal = Start->Codegen();
1256   if (StartVal == 0) return 0;
1257
1258   // Store the value into the alloca.
1259   Builder.CreateStore(StartVal, Alloca);
1260
1261   // Make the new basic block for the loop header, inserting after current
1262   // block.
1263   BasicBlock *LoopBB = BasicBlock::Create(TheContext, "loop", TheFunction);
1264
1265   // Insert an explicit fall through from the current block to the LoopBB.
1266   Builder.CreateBr(LoopBB);
1267
1268   // Start insertion in LoopBB.
1269   Builder.SetInsertPoint(LoopBB);
1270
1271   // Within the loop, the variable is defined equal to the PHI node.  If it
1272   // shadows an existing variable, we have to restore it, so save it now.
1273   AllocaInst *OldVal = NamedValues[VarName];
1274   NamedValues[VarName] = Alloca;
1275
1276   // Emit the body of the loop.  This, like any other expr, can change the
1277   // current BB.  Note that we ignore the value computed by the body, but don't
1278   // allow an error.
1279   if (Body->Codegen() == 0)
1280     return 0;
1281
1282   // Emit the step value.
1283   Value *StepVal;
1284   if (Step) {
1285     StepVal = Step->Codegen();
1286     if (StepVal == 0) return 0;
1287   } else {
1288     // If not specified, use 1.0.
1289     StepVal = ConstantFP::get(TheContext, APFloat(1.0));
1290   }
1291
1292   // Compute the end condition.
1293   Value *EndCond = End->Codegen();
1294   if (EndCond == 0) return EndCond;
1295
1296   // Reload, increment, and restore the alloca.  This handles the case where
1297   // the body of the loop mutates the variable.
1298   Value *CurVar = Builder.CreateLoad(Alloca, VarName.c_str());
1299   Value *NextVar = Builder.CreateFAdd(CurVar, StepVal, "nextvar");
1300   Builder.CreateStore(NextVar, Alloca);
1301
1302   // Convert condition to a bool by comparing equal to 0.0.
1303   EndCond = Builder.CreateFCmpONE(
1304       EndCond, ConstantFP::get(TheContext, APFloat(0.0)), "loopcond");
1305
1306   // Create the "after loop" block and insert it.
1307   BasicBlock *AfterBB =
1308       BasicBlock::Create(TheContext, "afterloop", TheFunction);
1309
1310   // Insert the conditional branch into the end of LoopEndBB.
1311   Builder.CreateCondBr(EndCond, LoopBB, AfterBB);
1312
1313   // Any new code will be inserted in AfterBB.
1314   Builder.SetInsertPoint(AfterBB);
1315
1316   // Restore the unshadowed variable.
1317   if (OldVal)
1318     NamedValues[VarName] = OldVal;
1319   else
1320     NamedValues.erase(VarName);
1321
1322
1323   // for expr always returns 0.0.
1324   return Constant::getNullValue(Type::getDoubleTy(TheContext));
1325 }
1326
1327 Value *VarExprAST::Codegen() {
1328   std::vector<AllocaInst *> OldBindings;
1329
1330   Function *TheFunction = Builder.GetInsertBlock()->getParent();
1331
1332   // Register all variables and emit their initializer.
1333   for (unsigned i = 0, e = VarNames.size(); i != e; ++i) {
1334     const std::string &VarName = VarNames[i].first;
1335     ExprAST *Init = VarNames[i].second;
1336
1337     // Emit the initializer before adding the variable to scope, this prevents
1338     // the initializer from referencing the variable itself, and permits stuff
1339     // like this:
1340     //  var a = 1 in
1341     //    var a = a in ...   # refers to outer 'a'.
1342     Value *InitVal;
1343     if (Init) {
1344       InitVal = Init->Codegen();
1345       if (InitVal == 0) return 0;
1346     } else { // If not specified, use 0.0.
1347       InitVal = ConstantFP::get(TheContext, APFloat(0.0));
1348     }
1349
1350     AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
1351     Builder.CreateStore(InitVal, Alloca);
1352
1353     // Remember the old variable binding so that we can restore the binding when
1354     // we unrecurse.
1355     OldBindings.push_back(NamedValues[VarName]);
1356
1357     // Remember this binding.
1358     NamedValues[VarName] = Alloca;
1359   }
1360
1361   // Codegen the body, now that all vars are in scope.
1362   Value *BodyVal = Body->Codegen();
1363   if (BodyVal == 0) return 0;
1364
1365   // Pop all our variables from scope.
1366   for (unsigned i = 0, e = VarNames.size(); i != e; ++i)
1367     NamedValues[VarNames[i].first] = OldBindings[i];
1368
1369   // Return the body computation.
1370   return BodyVal;
1371 }
1372
1373 Function *PrototypeAST::Codegen() {
1374   // Make the function type:  double(double,double) etc.
1375   std::vector<Type *> Doubles(Args.size(), Type::getDoubleTy(TheContext));
1376   FunctionType *FT =
1377       FunctionType::get(Type::getDoubleTy(TheContext), Doubles, false);
1378
1379   std::string FnName;
1380   FnName = MakeLegalFunctionName(Name);
1381
1382   Module* M = TheHelper->getModuleForNewFunction();
1383   Function *F = Function::Create(FT, Function::ExternalLinkage, FnName, M);
1384
1385   // FIXME: Implement duplicate function detection.
1386   // The check below will only work if the duplicate is in the open module.
1387   // If F conflicted, there was already something named 'Name'.  If it has a
1388   // body, don't allow redefinition or reextern.
1389   if (F->getName() != FnName) {
1390     // Delete the one we just made and get the existing one.
1391     F->eraseFromParent();
1392     F = M->getFunction(FnName);
1393     // If F already has a body, reject this.
1394     if (!F->empty()) {
1395       ErrorF("redefinition of function");
1396       return 0;
1397     }
1398     // If F took a different number of args, reject.
1399     if (F->arg_size() != Args.size()) {
1400       ErrorF("redefinition of function with different # args");
1401       return 0;
1402     }
1403   }
1404
1405   // Set names for all arguments.
1406   unsigned Idx = 0;
1407   for (Function::arg_iterator AI = F->arg_begin(); Idx != Args.size();
1408        ++AI, ++Idx)
1409     AI->setName(Args[Idx]);
1410
1411   return F;
1412 }
1413
1414 /// CreateArgumentAllocas - Create an alloca for each argument and register the
1415 /// argument in the symbol table so that references to it will succeed.
1416 void PrototypeAST::CreateArgumentAllocas(Function *F) {
1417   Function::arg_iterator AI = F->arg_begin();
1418   for (unsigned Idx = 0, e = Args.size(); Idx != e; ++Idx, ++AI) {
1419     // Create an alloca for this variable.
1420     AllocaInst *Alloca = CreateEntryBlockAlloca(F, Args[Idx]);
1421
1422     // Store the initial value into the alloca.
1423     Builder.CreateStore(AI, Alloca);
1424
1425     // Add arguments to variable symbol table.
1426     NamedValues[Args[Idx]] = Alloca;
1427   }
1428 }
1429
1430 Function *FunctionAST::Codegen() {
1431   NamedValues.clear();
1432
1433   Function *TheFunction = Proto->Codegen();
1434   if (TheFunction == 0)
1435     return 0;
1436
1437   // If this is an operator, install it.
1438   if (Proto->isBinaryOp())
1439     BinopPrecedence[Proto->getOperatorName()] = Proto->getBinaryPrecedence();
1440
1441   // Create a new basic block to start insertion into.
1442   BasicBlock *BB = BasicBlock::Create(TheContext, "entry", TheFunction);
1443   Builder.SetInsertPoint(BB);
1444
1445   // Add all arguments to the symbol table and create their allocas.
1446   Proto->CreateArgumentAllocas(TheFunction);
1447
1448   if (Value *RetVal = Body->Codegen()) {
1449     // Finish off the function.
1450     Builder.CreateRet(RetVal);
1451
1452     // Validate the generated code, checking for consistency.
1453     verifyFunction(*TheFunction);
1454
1455     return TheFunction;
1456   }
1457
1458   // Error reading body, remove function.
1459   TheFunction->eraseFromParent();
1460
1461   if (Proto->isBinaryOp())
1462     BinopPrecedence.erase(Proto->getOperatorName());
1463   return 0;
1464 }
1465
1466 //===----------------------------------------------------------------------===//
1467 // Top-Level parsing and JIT Driver
1468 //===----------------------------------------------------------------------===//
1469
1470 static void HandleDefinition() {
1471   if (FunctionAST *F = ParseDefinition()) {
1472     if (EnableLazyCompilation)
1473       TheHelper->closeCurrentModule();
1474     Function *LF = F->Codegen();
1475     if (LF && VerboseOutput) {
1476       fprintf(stderr, "Read function definition:");
1477       LF->print(errs());
1478       fprintf(stderr, "\n");
1479     }
1480   } else {
1481     // Skip token for error recovery.
1482     getNextToken();
1483   }
1484 }
1485
1486 static void HandleExtern() {
1487   if (PrototypeAST *P = ParseExtern()) {
1488     Function *F = P->Codegen();
1489     if (F && VerboseOutput) {
1490       fprintf(stderr, "Read extern: ");
1491       F->print(errs());
1492       fprintf(stderr, "\n");
1493     }
1494   } else {
1495     // Skip token for error recovery.
1496     getNextToken();
1497   }
1498 }
1499
1500 static void HandleTopLevelExpression() {
1501   // Evaluate a top-level expression into an anonymous function.
1502   if (FunctionAST *F = ParseTopLevelExpr()) {
1503     if (Function *LF = F->Codegen()) {
1504       // JIT the function, returning a function pointer.
1505       void *FPtr = TheHelper->getPointerToFunction(LF);
1506       // Cast it to the right type (takes no arguments, returns a double) so we
1507       // can call it as a native function.
1508       double (*FP)() = (double (*)())(intptr_t)FPtr;
1509       double Result = FP();
1510       if (VerboseOutput)
1511         fprintf(stderr, "Evaluated to %f\n", Result);
1512     }
1513   } else {
1514     // Skip token for error recovery.
1515     getNextToken();
1516   }
1517 }
1518
1519 /// top ::= definition | external | expression | ';'
1520 static void MainLoop() {
1521   while (1) {
1522     if (!SuppressPrompts)
1523       fprintf(stderr, "ready> ");
1524     switch (CurTok) {
1525     case tok_eof:    return;
1526     case ';':        getNextToken(); break;  // ignore top-level semicolons.
1527     case tok_def:    HandleDefinition(); break;
1528     case tok_extern: HandleExtern(); break;
1529     default:         HandleTopLevelExpression(); break;
1530     }
1531   }
1532 }
1533
1534 //===----------------------------------------------------------------------===//
1535 // "Library" functions that can be "extern'd" from user code.
1536 //===----------------------------------------------------------------------===//
1537
1538 /// putchard - putchar that takes a double and returns 0.
1539 extern "C"
1540 double putchard(double X) {
1541   putchar((char)X);
1542   return 0;
1543 }
1544
1545 /// printd - printf that takes a double prints it as "%f\n", returning 0.
1546 extern "C"
1547 double printd(double X) {
1548   printf("%f", X);
1549   return 0;
1550 }
1551
1552 extern "C"
1553 double printlf() {
1554   printf("\n");
1555   return 0;
1556 }
1557
1558 //===----------------------------------------------------------------------===//
1559 // Main driver code.
1560 //===----------------------------------------------------------------------===//
1561
1562 int main(int argc, char **argv) {
1563   InitializeNativeTarget();
1564   InitializeNativeTargetAsmPrinter();
1565   InitializeNativeTargetAsmParser();
1566   LLVMContext &Context = TheContext;
1567
1568   cl::ParseCommandLineOptions(argc, argv,
1569                               "Kaleidoscope example program\n");
1570
1571   // Install standard binary operators.
1572   // 1 is lowest precedence.
1573   BinopPrecedence['='] = 2;
1574   BinopPrecedence['<'] = 10;
1575   BinopPrecedence['+'] = 20;
1576   BinopPrecedence['-'] = 20;
1577   BinopPrecedence['/'] = 40;
1578   BinopPrecedence['*'] = 40;  // highest.
1579
1580   // Make the Helper, which holds all the code.
1581   TheHelper = new MCJITHelper(Context);
1582
1583   // Prime the first token.
1584   if (!SuppressPrompts)
1585     fprintf(stderr, "ready> ");
1586   getNextToken();
1587
1588   // Run the main "interpreter loop" now.
1589   MainLoop();
1590
1591   // Print out all of the generated code.
1592   if (DumpModulesOnExit)
1593     TheHelper->dump();
1594
1595   return 0;
1596 }