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

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