llvm/examples/Kaleidoscope/BuildingAJIT/Chapter4/toy.cpp

   1 #include "llvm/ADT/APFloat.h"
   2 #include "llvm/ADT/STLExtras.h"
   3 #include "llvm/IR/BasicBlock.h"
   4 #include "llvm/IR/Constants.h"
   5 #include "llvm/IR/DerivedTypes.h"
   6 #include "llvm/IR/Function.h"
   7 #include "llvm/IR/Instructions.h"
   8 #include "llvm/IR/IRBuilder.h"
   9 #include "llvm/IR/LLVMContext.h"
  10 #include "llvm/IR/Module.h"
  11 #include "llvm/IR/Type.h"
  12 #include "llvm/IR/Verifier.h"
  13 #include "llvm/Support/TargetSelect.h"
  14 #include "llvm/Target/TargetMachine.h"
  15 #include "KaleidoscopeJIT.h"
  16 #include <algorithm>
  17 #include <cassert>
  18 #include <cctype>
  19 #include <cstdint>
  20 #include <cstdio>
  21 #include <cstdlib>
  22 #include <map>
  23 #include <memory>
  24 #include <string>
  25 #include <utility>
  26 #include <vector>
  27
  28 using namespace llvm;
  29 using namespace llvm::orc;
  30
  31 //===----------------------------------------------------------------------===//
  32 // Lexer
  33 //===----------------------------------------------------------------------===//
  34
  35 // The lexer returns tokens [0-255] if it is an unknown character, otherwise one
  36 // of these for known things.
  37 enum Token {
  38   tok_eof = -1,
  39
  40   // commands
  41   tok_def = -2,
  42   tok_extern = -3,
  43
  44   // primary
  45   tok_identifier = -4,
  46   tok_number = -5,
  47
  48   // control
  49   tok_if = -6,
  50   tok_then = -7,
  51   tok_else = -8,
  52   tok_for = -9,
  53   tok_in = -10,
  54
  55   // operators
  56   tok_binary = -11,
  57   tok_unary = -12,
  58
  59   // var definition
  60   tok_var = -13
  61 };
  62
  63 static std::string IdentifierStr; // Filled in if tok_identifier
  64 static double NumVal;             // Filled in if tok_number
  65
  66 /// gettok - Return the next token from standard input.
  67 static int gettok() {
  68   static int LastChar = ' ';
  69
  70   // Skip any whitespace.
  71   while (isspace(LastChar))
  72     LastChar = getchar();
  73
  74   if (isalpha(LastChar)) { // identifier: [a-zA-Z][a-zA-Z0-9]*
  75     IdentifierStr = LastChar;
  76     while (isalnum((LastChar = getchar())))
  77       IdentifierStr += LastChar;
  78
  79     if (IdentifierStr == "def")
  80       return tok_def;
  81     if (IdentifierStr == "extern")
  82       return tok_extern;
  83     if (IdentifierStr == "if")
  84       return tok_if;
  85     if (IdentifierStr == "then")
  86       return tok_then;
  87     if (IdentifierStr == "else")
  88       return tok_else;
  89     if (IdentifierStr == "for")
  90       return tok_for;
  91     if (IdentifierStr == "in")
  92       return tok_in;
  93     if (IdentifierStr == "binary")
  94       return tok_binary;
  95     if (IdentifierStr == "unary")
  96       return tok_unary;
  97     if (IdentifierStr == "var")
  98       return tok_var;
  99     return tok_identifier;
 100   }
 101
 102   if (isdigit(LastChar) || LastChar == '.') { // Number: [0-9.]+
 103     std::string NumStr;
 104     do {
 105       NumStr += LastChar;
 106       LastChar = getchar();
 107     } while (isdigit(LastChar) || LastChar == '.');
 108
 109     NumVal = strtod(NumStr.c_str(), nullptr);
 110     return tok_number;
 111   }
 112
 113   if (LastChar == '#') {
 114     // Comment until end of line.
 115     do
 116       LastChar = getchar();
 117     while (LastChar != EOF && LastChar != '\n' && LastChar != '\r');
 118
 119     if (LastChar != EOF)
 120       return gettok();
 121   }
 122
 123   // Check for end of file.  Don't eat the EOF.
 124   if (LastChar == EOF)
 125     return tok_eof;
 126
 127   // Otherwise, just return the character as its ascii value.
 128   int ThisChar = LastChar;
 129   LastChar = getchar();
 130   return ThisChar;
 131 }
 132
 133 //===----------------------------------------------------------------------===//
 134 // Abstract Syntax Tree (aka Parse Tree)
 135 //===----------------------------------------------------------------------===//
 136
 137 /// ExprAST - Base class for all expression nodes.
 138 class ExprAST {
 139 public:
 140   virtual ~ExprAST() = default;
 141
 142   virtual Value *codegen() = 0;
 143 };
 144
 145 /// NumberExprAST - Expression class for numeric literals like "1.0".
 146 class NumberExprAST : public ExprAST {
 147   double Val;
 148
 149 public:
 150   NumberExprAST(double Val) : Val(Val) {}
 151
 152   Value *codegen() override;
 153 };
 154
 155 /// VariableExprAST - Expression class for referencing a variable, like "a".
 156 class VariableExprAST : public ExprAST {
 157   std::string Name;
 158
 159 public:
 160   VariableExprAST(const std::string &Name) : Name(Name) {}
 161
 162   Value *codegen() override;
 163   const std::string &getName() const { return Name; }
 164 };
 165
 166 /// UnaryExprAST - Expression class for a unary operator.
 167 class UnaryExprAST : public ExprAST {
 168   char Opcode;
 169   std::unique_ptr<ExprAST> Operand;
 170
 171 public:
 172   UnaryExprAST(char Opcode, std::unique_ptr<ExprAST> Operand)
 173       : Opcode(Opcode), Operand(std::move(Operand)) {}
 174
 175   Value *codegen() override;
 176 };
 177
 178 /// BinaryExprAST - Expression class for a binary operator.
 179 class BinaryExprAST : public ExprAST {
 180   char Op;
 181   std::unique_ptr<ExprAST> LHS, RHS;
 182
 183 public:
 184   BinaryExprAST(char Op, std::unique_ptr<ExprAST> LHS,
 185                 std::unique_ptr<ExprAST> RHS)
 186       : Op(Op), LHS(std::move(LHS)), RHS(std::move(RHS)) {}
 187
 188   Value *codegen() override;
 189 };
 190
 191 /// CallExprAST - Expression class for function calls.
 192 class CallExprAST : public ExprAST {
 193   std::string Callee;
 194   std::vector<std::unique_ptr<ExprAST>> Args;
 195
 196 public:
 197   CallExprAST(const std::string &Callee,
 198               std::vector<std::unique_ptr<ExprAST>> Args)
 199       : Callee(Callee), Args(std::move(Args)) {}
 200
 201   Value *codegen() override;
 202 };
 203
 204 /// IfExprAST - Expression class for if/then/else.
 205 class IfExprAST : public ExprAST {
 206   std::unique_ptr<ExprAST> Cond, Then, Else;
 207
 208 public:
 209   IfExprAST(std::unique_ptr<ExprAST> Cond, std::unique_ptr<ExprAST> Then,
 210             std::unique_ptr<ExprAST> Else)
 211       : Cond(std::move(Cond)), Then(std::move(Then)), Else(std::move(Else)) {}
 212
 213   Value *codegen() override;
 214 };
 215
 216 /// ForExprAST - Expression class for for/in.
 217 class ForExprAST : public ExprAST {
 218   std::string VarName;
 219   std::unique_ptr<ExprAST> Start, End, Step, Body;
 220
 221 public:
 222   ForExprAST(const std::string &VarName, std::unique_ptr<ExprAST> Start,
 223              std::unique_ptr<ExprAST> End, std::unique_ptr<ExprAST> Step,
 224              std::unique_ptr<ExprAST> Body)
 225       : VarName(VarName), Start(std::move(Start)), End(std::move(End)),
 226         Step(std::move(Step)), Body(std::move(Body)) {}
 227
 228   Value *codegen() override;
 229 };
 230
 231 /// VarExprAST - Expression class for var/in
 232 class VarExprAST : public ExprAST {
 233   std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames;
 234   std::unique_ptr<ExprAST> Body;
 235
 236 public:
 237   VarExprAST(
 238       std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames,
 239       std::unique_ptr<ExprAST> Body)
 240       : VarNames(std::move(VarNames)), Body(std::move(Body)) {}
 241
 242   Value *codegen() override;
 243 };
 244
 245 /// PrototypeAST - This class represents the "prototype" for a function,
 246 /// which captures its name, and its argument names (thus implicitly the number
 247 /// of arguments the function takes), as well as if it is an operator.
 248 class PrototypeAST {
 249   std::string Name;
 250   std::vector<std::string> Args;
 251   bool IsOperator;
 252   unsigned Precedence; // Precedence if a binary op.
 253
 254 public:
 255   PrototypeAST(const std::string &Name, std::vector<std::string> Args,
 256                bool IsOperator = false, unsigned Prec = 0)
 257       : Name(Name), Args(std::move(Args)), IsOperator(IsOperator),
 258         Precedence(Prec) {}
 259
 260   Function *codegen();
 261   const std::string &getName() const { return Name; }
 262
 263   bool isUnaryOp() const { return IsOperator && Args.size() == 1; }
 264   bool isBinaryOp() const { return IsOperator && Args.size() == 2; }
 265
 266   char getOperatorName() const {
 267     assert(isUnaryOp() || isBinaryOp());
 268     return Name[Name.size() - 1];
 269   }
 270
 271   unsigned getBinaryPrecedence() const { return Precedence; }
 272 };
 273
 274 //===----------------------------------------------------------------------===//
 275 // Parser
 276 //===----------------------------------------------------------------------===//
 277
 278 /// CurTok/getNextToken - Provide a simple token buffer.  CurTok is the current
 279 /// token the parser is looking at.  getNextToken reads another token from the
 280 /// lexer and updates CurTok with its results.
 281 static int CurTok;
 282 static int getNextToken() { return CurTok = gettok(); }
 283
 284 /// BinopPrecedence - This holds the precedence for each binary operator that is
 285 /// defined.
 286 static std::map<char, int> BinopPrecedence;
 287
 288 /// GetTokPrecedence - Get the precedence of the pending binary operator token.
 289 static int GetTokPrecedence() {
 290   if (!isascii(CurTok))
 291     return -1;
 292
 293   // Make sure it's a declared binop.
 294   int TokPrec = BinopPrecedence[CurTok];
 295   if (TokPrec <= 0)
 296     return -1;
 297   return TokPrec;
 298 }
 299
 300 /// LogError* - These are little helper functions for error handling.
 301 std::unique_ptr<ExprAST> LogError(const char *Str) {
 302   fprintf(stderr, "Error: %s\n", Str);
 303   return nullptr;
 304 }
 305
 306 std::unique_ptr<PrototypeAST> LogErrorP(const char *Str) {
 307   LogError(Str);
 308   return nullptr;
 309 }
 310
 311 static std::unique_ptr<ExprAST> ParseExpression();
 312
 313 /// numberexpr ::= number
 314 static std::unique_ptr<ExprAST> ParseNumberExpr() {
 315   auto Result = std::make_unique<NumberExprAST>(NumVal);
 316   getNextToken(); // consume the number
 317   return std::move(Result);
 318 }
 319
 320 /// parenexpr ::= '(' expression ')'
 321 static std::unique_ptr<ExprAST> ParseParenExpr() {
 322   getNextToken(); // eat (.
 323   auto V = ParseExpression();
 324   if (!V)
 325     return nullptr;
 326
 327   if (CurTok != ')')
 328     return LogError("expected ')'");
 329   getNextToken(); // eat ).
 330   return V;
 331 }
 332
 333 /// identifierexpr
 334 ///   ::= identifier
 335 ///   ::= identifier '(' expression* ')'
 336 static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
 337   std::string IdName = IdentifierStr;
 338
 339   getNextToken(); // eat identifier.
 340
 341   if (CurTok != '(') // Simple variable ref.
 342     return std::make_unique<VariableExprAST>(IdName);
 343
 344   // Call.
 345   getNextToken(); // eat (
 346   std::vector<std::unique_ptr<ExprAST>> Args;
 347   if (CurTok != ')') {
 348     while (true) {
 349       if (auto Arg = ParseExpression())
 350         Args.push_back(std::move(Arg));
 351       else
 352         return nullptr;
 353
 354       if (CurTok == ')')
 355         break;
 356
 357       if (CurTok != ',')
 358         return LogError("Expected ')' or ',' in argument list");
 359       getNextToken();
 360     }
 361   }
 362
 363   // Eat the ')'.
 364   getNextToken();
 365
 366   return std::make_unique<CallExprAST>(IdName, std::move(Args));
 367 }
 368
 369 /// ifexpr ::= 'if' expression 'then' expression 'else' expression
 370 static std::unique_ptr<ExprAST> ParseIfExpr() {
 371   getNextToken(); // eat the if.
 372
 373   // condition.
 374   auto Cond = ParseExpression();
 375   if (!Cond)
 376     return nullptr;
 377
 378   if (CurTok != tok_then)
 379     return LogError("expected then");
 380   getNextToken(); // eat the then
 381
 382   auto Then = ParseExpression();
 383   if (!Then)
 384     return nullptr;
 385
 386   if (CurTok != tok_else)
 387     return LogError("expected else");
 388
 389   getNextToken();
 390
 391   auto Else = ParseExpression();
 392   if (!Else)
 393     return nullptr;
 394
 395   return std::make_unique<IfExprAST>(std::move(Cond), std::move(Then),
 396                                       std::move(Else));
 397 }
 398
 399 /// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression
 400 static std::unique_ptr<ExprAST> ParseForExpr() {
 401   getNextToken(); // eat the for.
 402
 403   if (CurTok != tok_identifier)
 404     return LogError("expected identifier after for");
 405
 406   std::string IdName = IdentifierStr;
 407   getNextToken(); // eat identifier.
 408
 409   if (CurTok != '=')
 410     return LogError("expected '=' after for");
 411   getNextToken(); // eat '='.
 412
 413   auto Start = ParseExpression();
 414   if (!Start)
 415     return nullptr;
 416   if (CurTok != ',')
 417     return LogError("expected ',' after for start value");
 418   getNextToken();
 419
 420   auto End = ParseExpression();
 421   if (!End)
 422     return nullptr;
 423
 424   // The step value is optional.
 425   std::unique_ptr<ExprAST> Step;
 426   if (CurTok == ',') {
 427     getNextToken();
 428     Step = ParseExpression();
 429     if (!Step)
 430       return nullptr;
 431   }
 432
 433   if (CurTok != tok_in)
 434     return LogError("expected 'in' after for");
 435   getNextToken(); // eat 'in'.
 436
 437   auto Body = ParseExpression();
 438   if (!Body)
 439     return nullptr;
 440
 441   return std::make_unique<ForExprAST>(IdName, std::move(Start), std::move(End),
 442                                        std::move(Step), std::move(Body));
 443 }
 444
 445 /// varexpr ::= 'var' identifier ('=' expression)?
 446 //                    (',' identifier ('=' expression)?)* 'in' expression
 447 static std::unique_ptr<ExprAST> ParseVarExpr() {
 448   getNextToken(); // eat the var.
 449
 450   std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames;
 451
 452   // At least one variable name is required.
 453   if (CurTok != tok_identifier)
 454     return LogError("expected identifier after var");
 455
 456   while (true) {
 457     std::string Name = IdentifierStr;
 458     getNextToken(); // eat identifier.
 459
 460     // Read the optional initializer.
 461     std::unique_ptr<ExprAST> Init = nullptr;
 462     if (CurTok == '=') {
 463       getNextToken(); // eat the '='.
 464
 465       Init = ParseExpression();
 466       if (!Init)
 467         return nullptr;
 468     }
 469
 470     VarNames.push_back(std::make_pair(Name, std::move(Init)));
 471
 472     // End of var list, exit loop.
 473     if (CurTok != ',')
 474       break;
 475     getNextToken(); // eat the ','.
 476
 477     if (CurTok != tok_identifier)
 478       return LogError("expected identifier list after var");
 479   }
 480
 481   // At this point, we have to have 'in'.
 482   if (CurTok != tok_in)
 483     return LogError("expected 'in' keyword after 'var'");
 484   getNextToken(); // eat 'in'.
 485
 486   auto Body = ParseExpression();
 487   if (!Body)
 488     return nullptr;
 489
 490   return std::make_unique<VarExprAST>(std::move(VarNames), std::move(Body));
 491 }
 492
 493 /// primary
 494 ///   ::= identifierexpr
 495 ///   ::= numberexpr
 496 ///   ::= parenexpr
 497 ///   ::= ifexpr
 498 ///   ::= forexpr
 499 ///   ::= varexpr
 500 static std::unique_ptr<ExprAST> ParsePrimary() {
 501   switch (CurTok) {
 502   default:
 503     return LogError("unknown token when expecting an expression");
 504   case tok_identifier:
 505     return ParseIdentifierExpr();
 506   case tok_number:
 507     return ParseNumberExpr();
 508   case '(':
 509     return ParseParenExpr();
 510   case tok_if:
 511     return ParseIfExpr();
 512   case tok_for:
 513     return ParseForExpr();
 514   case tok_var:
 515     return ParseVarExpr();
 516   }
 517 }
 518
 519 /// unary
 520 ///   ::= primary
 521 ///   ::= '!' unary
 522 static std::unique_ptr<ExprAST> ParseUnary() {
 523   // If the current token is not an operator, it must be a primary expr.
 524   if (!isascii(CurTok) || CurTok == '(' || CurTok == ',')
 525     return ParsePrimary();
 526
 527   // If this is a unary operator, read it.
 528   int Opc = CurTok;
 529   getNextToken();
 530   if (auto Operand = ParseUnary())
 531     return std::make_unique<UnaryExprAST>(Opc, std::move(Operand));
 532   return nullptr;
 533 }
 534
 535 /// binoprhs
 536 ///   ::= ('+' unary)*
 537 static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec,
 538                                               std::unique_ptr<ExprAST> LHS) {
 539   // If this is a binop, find its precedence.
 540   while (true) {
 541     int TokPrec = GetTokPrecedence();
 542
 543     // If this is a binop that binds at least as tightly as the current binop,
 544     // consume it, otherwise we are done.
 545     if (TokPrec < ExprPrec)
 546       return LHS;
 547
 548     // Okay, we know this is a binop.
 549     int BinOp = CurTok;
 550     getNextToken(); // eat binop
 551
 552     // Parse the unary expression after the binary operator.
 553     auto RHS = ParseUnary();
 554     if (!RHS)
 555       return nullptr;
 556
 557     // If BinOp binds less tightly with RHS than the operator after RHS, let
 558     // the pending operator take RHS as its LHS.
 559     int NextPrec = GetTokPrecedence();
 560     if (TokPrec < NextPrec) {
 561       RHS = ParseBinOpRHS(TokPrec + 1, std::move(RHS));
 562       if (!RHS)
 563         return nullptr;
 564     }
 565
 566     // Merge LHS/RHS.
 567     LHS =
 568         std::make_unique<BinaryExprAST>(BinOp, std::move(LHS), std::move(RHS));
 569   }
 570 }
 571
 572 /// expression
 573 ///   ::= unary binoprhs
 574 ///
 575 static std::unique_ptr<ExprAST> ParseExpression() {
 576   auto LHS = ParseUnary();
 577   if (!LHS)
 578     return nullptr;
 579
 580   return ParseBinOpRHS(0, std::move(LHS));
 581 }
 582
 583 /// prototype
 584 ///   ::= id '(' id* ')'
 585 ///   ::= binary LETTER number? (id, id)
 586 ///   ::= unary LETTER (id)
 587 static std::unique_ptr<PrototypeAST> ParsePrototype() {
 588   std::string FnName;
 589
 590   unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.
 591   unsigned BinaryPrecedence = 30;
 592
 593   switch (CurTok) {
 594   default:
 595     return LogErrorP("Expected function name in prototype");
 596   case tok_identifier:
 597     FnName = IdentifierStr;
 598     Kind = 0;
 599     getNextToken();
 600     break;
 601   case tok_unary:
 602     getNextToken();
 603     if (!isascii(CurTok))
 604       return LogErrorP("Expected unary operator");
 605     FnName = "unary";
 606     FnName += (char)CurTok;
 607     Kind = 1;
 608     getNextToken();
 609     break;
 610   case tok_binary:
 611     getNextToken();
 612     if (!isascii(CurTok))
 613       return LogErrorP("Expected binary operator");
 614     FnName = "binary";
 615     FnName += (char)CurTok;
 616     Kind = 2;
 617     getNextToken();
 618
 619     // Read the precedence if present.
 620     if (CurTok == tok_number) {
 621       if (NumVal < 1 || NumVal > 100)
 622         return LogErrorP("Invalid precedecnce: must be 1..100");
 623       BinaryPrecedence = (unsigned)NumVal;
 624       getNextToken();
 625     }
 626     break;
 627   }
 628
 629   if (CurTok != '(')
 630     return LogErrorP("Expected '(' in prototype");
 631
 632   std::vector<std::string> ArgNames;
 633   while (getNextToken() == tok_identifier)
 634     ArgNames.push_back(IdentifierStr);
 635   if (CurTok != ')')
 636     return LogErrorP("Expected ')' in prototype");
 637
 638   // success.
 639   getNextToken(); // eat ')'.
 640
 641   // Verify right number of names for operator.
 642   if (Kind && ArgNames.size() != Kind)
 643     return LogErrorP("Invalid number of operands for operator");
 644
 645   return std::make_unique<PrototypeAST>(FnName, ArgNames, Kind != 0,
 646                                          BinaryPrecedence);
 647 }
 648
 649 /// definition ::= 'def' prototype expression
 650 static std::unique_ptr<FunctionAST> ParseDefinition() {
 651   getNextToken(); // eat def.
 652   auto Proto = ParsePrototype();
 653   if (!Proto)
 654     return nullptr;
 655
 656   if (auto E = ParseExpression())
 657     return std::make_unique<FunctionAST>(std::move(Proto), std::move(E));
 658   return nullptr;
 659 }
 660
 661 /// toplevelexpr ::= expression
 662 static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
 663   if (auto E = ParseExpression()) {
 664     // Make an anonymous proto.
 665     auto Proto = std::make_unique<PrototypeAST>("__anon_expr",
 666                                                 std::vector<std::string>());
 667     return std::make_unique<FunctionAST>(std::move(Proto), std::move(E));
 668   }
 669   return nullptr;
 670 }
 671
 672 /// external ::= 'extern' prototype
 673 static std::unique_ptr<PrototypeAST> ParseExtern() {
 674   getNextToken(); // eat extern.
 675   return ParsePrototype();
 676 }
 677
 678 //===----------------------------------------------------------------------===//
 679 // Code Generation
 680 //===----------------------------------------------------------------------===//
 681
 682 static std::unique_ptr<KaleidoscopeJIT> TheJIT;
 683 static std::unique_ptr<LLVMContext> TheContext;
 684 static std::unique_ptr<IRBuilder<>> Builder;
 685 static std::unique_ptr<Module> TheModule;
 686 static std::map<std::string, AllocaInst *> NamedValues;
 687 static std::map<std::string, std::unique_ptr<PrototypeAST>> FunctionProtos;
 688 static ExitOnError ExitOnErr;
 689
 690 Value *LogErrorV(const char *Str) {
 691   LogError(Str);
 692   return nullptr;
 693 }
 694
 695 Function *getFunction(std::string Name) {
 696   // First, see if the function has already been added to the current module.
 697   if (auto *F = TheModule->getFunction(Name))
 698     return F;
 699
 700   // If not, check whether we can codegen the declaration from some existing
 701   // prototype.
 702   auto FI = FunctionProtos.find(Name);
 703   if (FI != FunctionProtos.end())
 704     return FI->second->codegen();
 705
 706   // If no existing prototype exists, return null.
 707   return nullptr;
 708 }
 709
 710 /// CreateEntryBlockAlloca - Create an alloca instruction in the entry block of
 711 /// the function.  This is used for mutable variables etc.
 712 static AllocaInst *CreateEntryBlockAlloca(Function *TheFunction,
 713                                           StringRef VarName) {
 714   IRBuilder<> TmpB(&TheFunction->getEntryBlock(),
 715                    TheFunction->getEntryBlock().begin());
 716   return TmpB.CreateAlloca(Type::getDoubleTy(*TheContext), nullptr, VarName);
 717 }
 718
 719 Value *NumberExprAST::codegen() {
 720   return ConstantFP::get(*TheContext, APFloat(Val));
 721 }
 722
 723 Value *VariableExprAST::codegen() {
 724   // Look this variable up in the function.
 725   Value *V = NamedValues[Name];
 726   if (!V)
 727     return LogErrorV("Unknown variable name");
 728
 729   // Load the value.
 730   return Builder->CreateLoad(Type::getDoubleTy(*TheContext), V, Name.c_str());
 731 }
 732
 733 Value *UnaryExprAST::codegen() {
 734   Value *OperandV = Operand->codegen();
 735   if (!OperandV)
 736     return nullptr;
 737
 738   Function *F = getFunction(std::string("unary") + Opcode);
 739   if (!F)
 740     return LogErrorV("Unknown unary operator");
 741
 742   return Builder->CreateCall(F, OperandV, "unop");
 743 }
 744
 745 Value *BinaryExprAST::codegen() {
 746   // Special case '=' because we don't want to emit the LHS as an expression.
 747   if (Op == '=') {
 748     // Assignment requires the LHS to be an identifier.
 749     // This assume we're building without RTTI because LLVM builds that way by
 750     // default.  If you build LLVM with RTTI this can be changed to a
 751     // dynamic_cast for automatic error checking.
 752     VariableExprAST *LHSE = static_cast<VariableExprAST *>(LHS.get());
 753     if (!LHSE)
 754       return LogErrorV("destination of '=' must be a variable");
 755     // Codegen the RHS.
 756     Value *Val = RHS->codegen();
 757     if (!Val)
 758       return nullptr;
 759
 760     // Look up the name.
 761     Value *Variable = NamedValues[LHSE->getName()];
 762     if (!Variable)
 763       return LogErrorV("Unknown variable name");
 764
 765     Builder->CreateStore(Val, Variable);
 766     return Val;
 767   }
 768
 769   Value *L = LHS->codegen();
 770   Value *R = RHS->codegen();
 771   if (!L || !R)
 772     return nullptr;
 773
 774   switch (Op) {
 775   case '+':
 776     return Builder->CreateFAdd(L, R, "addtmp");
 777   case '-':
 778     return Builder->CreateFSub(L, R, "subtmp");
 779   case '*':
 780     return Builder->CreateFMul(L, R, "multmp");
 781   case '<':
 782     L = Builder->CreateFCmpULT(L, R, "cmptmp");
 783     // Convert bool 0/1 to double 0.0 or 1.0
 784     return Builder->CreateUIToFP(L, Type::getDoubleTy(*TheContext), "booltmp");
 785   default:
 786     break;
 787   }
 788
 789   // If it wasn't a builtin binary operator, it must be a user defined one. Emit
 790   // a call to it.
 791   Function *F = getFunction(std::string("binary") + Op);
 792   assert(F && "binary operator not found!");
 793
 794   Value *Ops[] = {L, R};
 795   return Builder->CreateCall(F, Ops, "binop");
 796 }
 797
 798 Value *CallExprAST::codegen() {
 799   // Look up the name in the global module table.
 800   Function *CalleeF = getFunction(Callee);
 801   if (!CalleeF)
 802     return LogErrorV("Unknown function referenced");
 803
 804   // If argument mismatch error.
 805   if (CalleeF->arg_size() != Args.size())
 806     return LogErrorV("Incorrect # arguments passed");
 807
 808   std::vector<Value *> ArgsV;
 809   for (unsigned i = 0, e = Args.size(); i != e; ++i) {
 810     ArgsV.push_back(Args[i]->codegen());
 811     if (!ArgsV.back())
 812       return nullptr;
 813   }
 814
 815   return Builder->CreateCall(CalleeF, ArgsV, "calltmp");
 816 }
 817
 818 Value *IfExprAST::codegen() {
 819   Value *CondV = Cond->codegen();
 820   if (!CondV)
 821     return nullptr;
 822
 823   // Convert condition to a bool by comparing equal to 0.0.
 824   CondV = Builder->CreateFCmpONE(
 825       CondV, ConstantFP::get(*TheContext, APFloat(0.0)), "ifcond");
 826
 827   Function *TheFunction = Builder->GetInsertBlock()->getParent();
 828
 829   // Create blocks for the then and else cases.  Insert the 'then' block at the
 830   // end of the function.
 831   BasicBlock *ThenBB = BasicBlock::Create(*TheContext, "then", TheFunction);
 832   BasicBlock *ElseBB = BasicBlock::Create(*TheContext, "else");
 833   BasicBlock *MergeBB = BasicBlock::Create(*TheContext, "ifcont");
 834
 835   Builder->CreateCondBr(CondV, ThenBB, ElseBB);
 836
 837   // Emit then value.
 838   Builder->SetInsertPoint(ThenBB);
 839
 840   Value *ThenV = Then->codegen();
 841   if (!ThenV)
 842     return nullptr;
 843
 844   Builder->CreateBr(MergeBB);
 845   // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
 846   ThenBB = Builder->GetInsertBlock();
 847
 848   // Emit else block.
 849   TheFunction->getBasicBlockList().push_back(ElseBB);
 850   Builder->SetInsertPoint(ElseBB);
 851
 852   Value *ElseV = Else->codegen();
 853   if (!ElseV)
 854     return nullptr;
 855
 856   Builder->CreateBr(MergeBB);
 857   // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
 858   ElseBB = Builder->GetInsertBlock();
 859
 860   // Emit merge block.
 861   TheFunction->getBasicBlockList().push_back(MergeBB);
 862   Builder->SetInsertPoint(MergeBB);
 863   PHINode *PN = Builder->CreatePHI(Type::getDoubleTy(*TheContext), 2, "iftmp");
 864
 865   PN->addIncoming(ThenV, ThenBB);
 866   PN->addIncoming(ElseV, ElseBB);
 867   return PN;
 868 }
 869
 870 // Output for-loop as:
 871 //   var = alloca double
 872 //   ...
 873 //   start = startexpr
 874 //   store start -> var
 875 //   goto loop
 876 // loop:
 877 //   ...
 878 //   bodyexpr
 879 //   ...
 880 // loopend:
 881 //   step = stepexpr
 882 //   endcond = endexpr
 883 //
 884 //   curvar = load var
 885 //   nextvar = curvar + step
 886 //   store nextvar -> var
 887 //   br endcond, loop, endloop
 888 // outloop:
 889 Value *ForExprAST::codegen() {
 890   Function *TheFunction = Builder->GetInsertBlock()->getParent();
 891
 892   // Create an alloca for the variable in the entry block.
 893   AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
 894
 895   // Emit the start code first, without 'variable' in scope.
 896   Value *StartVal = Start->codegen();
 897   if (!StartVal)
 898     return nullptr;
 899
 900   // Store the value into the alloca.
 901   Builder->CreateStore(StartVal, Alloca);
 902
 903   // Make the new basic block for the loop header, inserting after current
 904   // block.
 905   BasicBlock *LoopBB = BasicBlock::Create(*TheContext, "loop", TheFunction);
 906
 907   // Insert an explicit fall through from the current block to the LoopBB.
 908   Builder->CreateBr(LoopBB);
 909
 910   // Start insertion in LoopBB.
 911   Builder->SetInsertPoint(LoopBB);
 912
 913   // Within the loop, the variable is defined equal to the PHI node.  If it
 914   // shadows an existing variable, we have to restore it, so save it now.
 915   AllocaInst *OldVal = NamedValues[VarName];
 916   NamedValues[VarName] = Alloca;
 917
 918   // Emit the body of the loop.  This, like any other expr, can change the
 919   // current BB.  Note that we ignore the value computed by the body, but don't
 920   // allow an error.
 921   if (!Body->codegen())
 922     return nullptr;
 923
 924   // Emit the step value.
 925   Value *StepVal = nullptr;
 926   if (Step) {
 927     StepVal = Step->codegen();
 928     if (!StepVal)
 929       return nullptr;
 930   } else {
 931     // If not specified, use 1.0.
 932     StepVal = ConstantFP::get(*TheContext, APFloat(1.0));
 933   }
 934
 935   // Compute the end condition.
 936   Value *EndCond = End->codegen();
 937   if (!EndCond)
 938     return nullptr;
 939
 940   // Reload, increment, and restore the alloca.  This handles the case where
 941   // the body of the loop mutates the variable.
 942   Value *CurVar = Builder->CreateLoad(Type::getDoubleTy(*TheContext), Alloca,
 943                                       VarName.c_str());
 944   Value *NextVar = Builder->CreateFAdd(CurVar, StepVal, "nextvar");
 945   Builder->CreateStore(NextVar, Alloca);
 946
 947   // Convert condition to a bool by comparing equal to 0.0.
 948   EndCond = Builder->CreateFCmpONE(
 949       EndCond, ConstantFP::get(*TheContext, APFloat(0.0)), "loopcond");
 950
 951   // Create the "after loop" block and insert it.
 952   BasicBlock *AfterBB =
 953       BasicBlock::Create(*TheContext, "afterloop", TheFunction);
 954
 955   // Insert the conditional branch into the end of LoopEndBB.
 956   Builder->CreateCondBr(EndCond, LoopBB, AfterBB);
 957
 958   // Any new code will be inserted in AfterBB.
 959   Builder->SetInsertPoint(AfterBB);
 960
 961   // Restore the unshadowed variable.
 962   if (OldVal)
 963     NamedValues[VarName] = OldVal;
 964   else
 965     NamedValues.erase(VarName);
 966
 967   // for expr always returns 0.0.
 968   return Constant::getNullValue(Type::getDoubleTy(*TheContext));
 969 }
 970
 971 Value *VarExprAST::codegen() {
 972   std::vector<AllocaInst *> OldBindings;
 973
 974   Function *TheFunction = Builder->GetInsertBlock()->getParent();
 975
 976   // Register all variables and emit their initializer.
 977   for (unsigned i = 0, e = VarNames.size(); i != e; ++i) {
 978     const std::string &VarName = VarNames[i].first;
 979     ExprAST *Init = VarNames[i].second.get();
 980
 981     // Emit the initializer before adding the variable to scope, this prevents
 982     // the initializer from referencing the variable itself, and permits stuff
 983     // like this:
 984     //  var a = 1 in
 985     //    var a = a in ...   # refers to outer 'a'.
 986     Value *InitVal;
 987     if (Init) {
 988       InitVal = Init->codegen();
 989       if (!InitVal)
 990         return nullptr;
 991     } else { // If not specified, use 0.0.
 992       InitVal = ConstantFP::get(*TheContext, APFloat(0.0));
 993     }
 994
 995     AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
 996     Builder->CreateStore(InitVal, Alloca);
 997
 998     // Remember the old variable binding so that we can restore the binding when
 999     // we unrecurse.
1000     OldBindings.push_back(NamedValues[VarName]);
1001
1002     // Remember this binding.
1003     NamedValues[VarName] = Alloca;
1004   }
1005
1006   // Codegen the body, now that all vars are in scope.
1007   Value *BodyVal = Body->codegen();
1008   if (!BodyVal)
1009     return nullptr;
1010
1011   // Pop all our variables from scope.
1012   for (unsigned i = 0, e = VarNames.size(); i != e; ++i)
1013     NamedValues[VarNames[i].first] = OldBindings[i];
1014
1015   // Return the body computation.
1016   return BodyVal;
1017 }
1018
1019 Function *PrototypeAST::codegen() {
1020   // Make the function type:  double(double,double) etc.
1021   std::vector<Type *> Doubles(Args.size(), Type::getDoubleTy(*TheContext));
1022   FunctionType *FT =
1023       FunctionType::get(Type::getDoubleTy(*TheContext), Doubles, false);
1024
1025   Function *F =
1026       Function::Create(FT, Function::ExternalLinkage, Name, TheModule.get());
1027
1028   // Set names for all arguments.
1029   unsigned Idx = 0;
1030   for (auto &Arg : F->args())
1031     Arg.setName(Args[Idx++]);
1032
1033   return F;
1034 }
1035
1036 const PrototypeAST& FunctionAST::getProto() const {
1037   return *Proto;
1038 }
1039
1040 const std::string& FunctionAST::getName() const {
1041   return Proto->getName();
1042 }
1043
1044 Function *FunctionAST::codegen() {
1045   // Transfer ownership of the prototype to the FunctionProtos map, but keep a
1046   // reference to it for use below.
1047   auto &P = *Proto;
1048   FunctionProtos[Proto->getName()] = std::move(Proto);
1049   Function *TheFunction = getFunction(P.getName());
1050   if (!TheFunction)
1051     return nullptr;
1052
1053   // If this is an operator, install it.
1054   if (P.isBinaryOp())
1055     BinopPrecedence[P.getOperatorName()] = P.getBinaryPrecedence();
1056
1057   // Create a new basic block to start insertion into.
1058   BasicBlock *BB = BasicBlock::Create(*TheContext, "entry", TheFunction);
1059   Builder->SetInsertPoint(BB);
1060
1061   // Record the function arguments in the NamedValues map.
1062   NamedValues.clear();
1063   for (auto &Arg : TheFunction->args()) {
1064     // Create an alloca for this variable.
1065     AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, Arg.getName());
1066
1067     // Store the initial value into the alloca.
1068     Builder->CreateStore(&Arg, Alloca);
1069
1070     // Add arguments to variable symbol table.
1071     NamedValues[std::string(Arg.getName())] = Alloca;
1072   }
1073
1074   if (Value *RetVal = Body->codegen()) {
1075     // Finish off the function.
1076     Builder->CreateRet(RetVal);
1077
1078     // Validate the generated code, checking for consistency.
1079     verifyFunction(*TheFunction);
1080
1081     return TheFunction;
1082   }
1083
1084   // Error reading body, remove function.
1085   TheFunction->eraseFromParent();
1086
1087   if (P.isBinaryOp())
1088     BinopPrecedence.erase(P.getOperatorName());
1089   return nullptr;
1090 }
1091
1092 //===----------------------------------------------------------------------===//
1093 // Top-Level parsing and JIT Driver
1094 //===----------------------------------------------------------------------===//
1095
1096 static void InitializeModule() {
1097   // Open a new context and module.
1098   TheContext = std::make_unique<LLVMContext>();
1099   TheModule = std::make_unique<Module>("my cool jit", *TheContext);
1100   TheModule->setDataLayout(TheJIT->getDataLayout());
1101
1102   // Create a new builder for the module.
1103   Builder = std::make_unique<IRBuilder<>>(*TheContext);
1104 }
1105
1106 ThreadSafeModule irgenAndTakeOwnership(FunctionAST &FnAST,
1107                                        const std::string &Suffix) {
1108   if (auto *F = FnAST.codegen()) {
1109     F->setName(F->getName() + Suffix);
1110     auto TSM = ThreadSafeModule(std::move(TheModule), std::move(TheContext));
1111     // Start a new module.
1112     InitializeModule();
1113     return TSM;
1114   } else
1115     report_fatal_error("Couldn't compile lazily JIT'd function");
1116 }
1117
1118 static void HandleDefinition() {
1119   if (auto FnAST = ParseDefinition()) {
1120     FunctionProtos[FnAST->getProto().getName()] =
1121       std::make_unique<PrototypeAST>(FnAST->getProto());
1122     ExitOnErr(TheJIT->addAST(std::move(FnAST)));
1123   } else {
1124     // Skip token for error recovery.
1125     getNextToken();
1126   }
1127 }
1128
1129 static void HandleExtern() {
1130   if (auto ProtoAST = ParseExtern()) {
1131     if (auto *FnIR = ProtoAST->codegen()) {
1132       fprintf(stderr, "Read extern: ");
1133       FnIR->print(errs());
1134       fprintf(stderr, "\n");
1135       FunctionProtos[ProtoAST->getName()] = std::move(ProtoAST);
1136     }
1137   } else {
1138     // Skip token for error recovery.
1139     getNextToken();
1140   }
1141 }
1142
1143 static void HandleTopLevelExpression() {
1144   // Evaluate a top-level expression into an anonymous function.
1145   if (auto FnAST = ParseTopLevelExpr()) {
1146     if (FnAST->codegen()) {
1147       // Create a ResourceTracker to track JIT'd memory allocated to our
1148       // anonymous expression -- that way we can free it after executing.
1149       auto RT = TheJIT->getMainJITDylib().createResourceTracker();
1150
1151       auto TSM = ThreadSafeModule(std::move(TheModule), std::move(TheContext));
1152       ExitOnErr(TheJIT->addModule(std::move(TSM), RT));
1153       InitializeModule();
1154
1155       // Get the anonymous expression's JITSymbol.
1156       auto Sym = ExitOnErr(TheJIT->lookup("__anon_expr"));
1157
1158       // Get the symbol's address and cast it to the right type (takes no
1159       // arguments, returns a double) so we can call it as a native function.
1160       auto *FP = (double (*)())(intptr_t)Sym.getAddress();
1161       fprintf(stderr, "Evaluated to %f\n", FP());
1162
1163       // Delete the anonymous expression module from the JIT.
1164       ExitOnErr(RT->remove());
1165     }
1166   } else {
1167     // Skip token for error recovery.
1168     getNextToken();
1169   }
1170 }
1171
1172 /// top ::= definition | external | expression | ';'
1173 static void MainLoop() {
1174   while (true) {
1175     fprintf(stderr, "ready> ");
1176     switch (CurTok) {
1177     case tok_eof:
1178       return;
1179     case ';': // ignore top-level semicolons.
1180       getNextToken();
1181       break;
1182     case tok_def:
1183       HandleDefinition();
1184       break;
1185     case tok_extern:
1186       HandleExtern();
1187       break;
1188     default:
1189       HandleTopLevelExpression();
1190       break;
1191     }
1192   }
1193 }
1194
1195 //===----------------------------------------------------------------------===//
1196 // "Library" functions that can be "extern'd" from user code.
1197 //===----------------------------------------------------------------------===//
1198
1199 /// putchard - putchar that takes a double and returns 0.
1200 extern "C" double putchard(double X) {
1201   fputc((char)X, stderr);
1202   return 0;
1203 }
1204
1205 /// printd - printf that takes a double prints it as "%f\n", returning 0.
1206 extern "C" double printd(double X) {
1207   fprintf(stderr, "%f\n", X);
1208   return 0;
1209 }
1210
1211 //===----------------------------------------------------------------------===//
1212 // Main driver code.
1213 //===----------------------------------------------------------------------===//
1214
1215 int main() {
1216   InitializeNativeTarget();
1217   InitializeNativeTargetAsmPrinter();
1218   InitializeNativeTargetAsmParser();
1219
1220   // Install standard binary operators.
1221   // 1 is lowest precedence.
1222   BinopPrecedence['='] = 2;
1223   BinopPrecedence['<'] = 10;
1224   BinopPrecedence['+'] = 20;
1225   BinopPrecedence['-'] = 20;
1226   BinopPrecedence['*'] = 40; // highest.
1227
1228   // Prime the first token.
1229   fprintf(stderr, "ready> ");
1230   getNextToken();
1231
1232   TheJIT = ExitOnErr(KaleidoscopeJIT::Create());
1233   InitializeModule();
1234
1235   // Run the main "interpreter loop" now.
1236   MainLoop();
1237
1238   return 0;
1239 }