[ThinLTO] Add code comment. NFC
[llvm-complete.git] / examples / Kaleidoscope / BuildingAJIT / Chapter3 / toy.cpp
blobe9505033106e70a4b7aa6510c263410ef392b4db
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>
28 using namespace llvm;
29 using namespace llvm::orc;
31 //===----------------------------------------------------------------------===//
32 // Lexer
33 //===----------------------------------------------------------------------===//
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,
40 // commands
41 tok_def = -2,
42 tok_extern = -3,
44 // primary
45 tok_identifier = -4,
46 tok_number = -5,
48 // control
49 tok_if = -6,
50 tok_then = -7,
51 tok_else = -8,
52 tok_for = -9,
53 tok_in = -10,
55 // operators
56 tok_binary = -11,
57 tok_unary = -12,
59 // var definition
60 tok_var = -13
63 static std::string IdentifierStr; // Filled in if tok_identifier
64 static double NumVal; // Filled in if tok_number
66 /// gettok - Return the next token from standard input.
67 static int gettok() {
68 static int LastChar = ' ';
70 // Skip any whitespace.
71 while (isspace(LastChar))
72 LastChar = getchar();
74 if (isalpha(LastChar)) { // identifier: [a-zA-Z][a-zA-Z0-9]*
75 IdentifierStr = LastChar;
76 while (isalnum((LastChar = getchar())))
77 IdentifierStr += LastChar;
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;
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 == '.');
109 NumVal = strtod(NumStr.c_str(), nullptr);
110 return tok_number;
113 if (LastChar == '#') {
114 // Comment until end of line.
116 LastChar = getchar();
117 while (LastChar != EOF && LastChar != '\n' && LastChar != '\r');
119 if (LastChar != EOF)
120 return gettok();
123 // Check for end of file. Don't eat the EOF.
124 if (LastChar == EOF)
125 return tok_eof;
127 // Otherwise, just return the character as its ascii value.
128 int ThisChar = LastChar;
129 LastChar = getchar();
130 return ThisChar;
133 //===----------------------------------------------------------------------===//
134 // Abstract Syntax Tree (aka Parse Tree)
135 //===----------------------------------------------------------------------===//
137 namespace {
139 /// ExprAST - Base class for all expression nodes.
140 class ExprAST {
141 public:
142 virtual ~ExprAST() = default;
144 virtual Value *codegen() = 0;
147 /// NumberExprAST - Expression class for numeric literals like "1.0".
148 class NumberExprAST : public ExprAST {
149 double Val;
151 public:
152 NumberExprAST(double Val) : Val(Val) {}
154 Value *codegen() override;
157 /// VariableExprAST - Expression class for referencing a variable, like "a".
158 class VariableExprAST : public ExprAST {
159 std::string Name;
161 public:
162 VariableExprAST(const std::string &Name) : Name(Name) {}
164 Value *codegen() override;
165 const std::string &getName() const { return Name; }
168 /// UnaryExprAST - Expression class for a unary operator.
169 class UnaryExprAST : public ExprAST {
170 char Opcode;
171 std::unique_ptr<ExprAST> Operand;
173 public:
174 UnaryExprAST(char Opcode, std::unique_ptr<ExprAST> Operand)
175 : Opcode(Opcode), Operand(std::move(Operand)) {}
177 Value *codegen() override;
180 /// BinaryExprAST - Expression class for a binary operator.
181 class BinaryExprAST : public ExprAST {
182 char Op;
183 std::unique_ptr<ExprAST> LHS, RHS;
185 public:
186 BinaryExprAST(char Op, std::unique_ptr<ExprAST> LHS,
187 std::unique_ptr<ExprAST> RHS)
188 : Op(Op), LHS(std::move(LHS)), RHS(std::move(RHS)) {}
190 Value *codegen() override;
193 /// CallExprAST - Expression class for function calls.
194 class CallExprAST : public ExprAST {
195 std::string Callee;
196 std::vector<std::unique_ptr<ExprAST>> Args;
198 public:
199 CallExprAST(const std::string &Callee,
200 std::vector<std::unique_ptr<ExprAST>> Args)
201 : Callee(Callee), Args(std::move(Args)) {}
203 Value *codegen() override;
206 /// IfExprAST - Expression class for if/then/else.
207 class IfExprAST : public ExprAST {
208 std::unique_ptr<ExprAST> Cond, Then, Else;
210 public:
211 IfExprAST(std::unique_ptr<ExprAST> Cond, std::unique_ptr<ExprAST> Then,
212 std::unique_ptr<ExprAST> Else)
213 : Cond(std::move(Cond)), Then(std::move(Then)), Else(std::move(Else)) {}
215 Value *codegen() override;
218 /// ForExprAST - Expression class for for/in.
219 class ForExprAST : public ExprAST {
220 std::string VarName;
221 std::unique_ptr<ExprAST> Start, End, Step, Body;
223 public:
224 ForExprAST(const std::string &VarName, std::unique_ptr<ExprAST> Start,
225 std::unique_ptr<ExprAST> End, std::unique_ptr<ExprAST> Step,
226 std::unique_ptr<ExprAST> Body)
227 : VarName(VarName), Start(std::move(Start)), End(std::move(End)),
228 Step(std::move(Step)), Body(std::move(Body)) {}
230 Value *codegen() override;
233 /// VarExprAST - Expression class for var/in
234 class VarExprAST : public ExprAST {
235 std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames;
236 std::unique_ptr<ExprAST> Body;
238 public:
239 VarExprAST(
240 std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames,
241 std::unique_ptr<ExprAST> Body)
242 : VarNames(std::move(VarNames)), Body(std::move(Body)) {}
244 Value *codegen() override;
247 /// PrototypeAST - This class represents the "prototype" for a function,
248 /// which captures its name, and its argument names (thus implicitly the number
249 /// of arguments the function takes), as well as if it is an operator.
250 class PrototypeAST {
251 std::string Name;
252 std::vector<std::string> Args;
253 bool IsOperator;
254 unsigned Precedence; // Precedence if a binary op.
256 public:
257 PrototypeAST(const std::string &Name, std::vector<std::string> Args,
258 bool IsOperator = false, unsigned Prec = 0)
259 : Name(Name), Args(std::move(Args)), IsOperator(IsOperator),
260 Precedence(Prec) {}
262 Function *codegen();
263 const std::string &getName() const { return Name; }
265 bool isUnaryOp() const { return IsOperator && Args.size() == 1; }
266 bool isBinaryOp() const { return IsOperator && Args.size() == 2; }
268 char getOperatorName() const {
269 assert(isUnaryOp() || isBinaryOp());
270 return Name[Name.size() - 1];
273 unsigned getBinaryPrecedence() const { return Precedence; }
276 /// FunctionAST - This class represents a function definition itself.
277 class FunctionAST {
278 std::unique_ptr<PrototypeAST> Proto;
279 std::unique_ptr<ExprAST> Body;
281 public:
282 FunctionAST(std::unique_ptr<PrototypeAST> Proto,
283 std::unique_ptr<ExprAST> Body)
284 : Proto(std::move(Proto)), Body(std::move(Body)) {}
286 Function *codegen();
289 } // end anonymous namespace
291 //===----------------------------------------------------------------------===//
292 // Parser
293 //===----------------------------------------------------------------------===//
295 /// CurTok/getNextToken - Provide a simple token buffer. CurTok is the current
296 /// token the parser is looking at. getNextToken reads another token from the
297 /// lexer and updates CurTok with its results.
298 static int CurTok;
299 static int getNextToken() { return CurTok = gettok(); }
301 /// BinopPrecedence - This holds the precedence for each binary operator that is
302 /// defined.
303 static std::map<char, int> BinopPrecedence;
305 /// GetTokPrecedence - Get the precedence of the pending binary operator token.
306 static int GetTokPrecedence() {
307 if (!isascii(CurTok))
308 return -1;
310 // Make sure it's a declared binop.
311 int TokPrec = BinopPrecedence[CurTok];
312 if (TokPrec <= 0)
313 return -1;
314 return TokPrec;
317 /// LogError* - These are little helper functions for error handling.
318 std::unique_ptr<ExprAST> LogError(const char *Str) {
319 fprintf(stderr, "Error: %s\n", Str);
320 return nullptr;
323 std::unique_ptr<PrototypeAST> LogErrorP(const char *Str) {
324 LogError(Str);
325 return nullptr;
328 static std::unique_ptr<ExprAST> ParseExpression();
330 /// numberexpr ::= number
331 static std::unique_ptr<ExprAST> ParseNumberExpr() {
332 auto Result = std::make_unique<NumberExprAST>(NumVal);
333 getNextToken(); // consume the number
334 return std::move(Result);
337 /// parenexpr ::= '(' expression ')'
338 static std::unique_ptr<ExprAST> ParseParenExpr() {
339 getNextToken(); // eat (.
340 auto V = ParseExpression();
341 if (!V)
342 return nullptr;
344 if (CurTok != ')')
345 return LogError("expected ')'");
346 getNextToken(); // eat ).
347 return V;
350 /// identifierexpr
351 /// ::= identifier
352 /// ::= identifier '(' expression* ')'
353 static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
354 std::string IdName = IdentifierStr;
356 getNextToken(); // eat identifier.
358 if (CurTok != '(') // Simple variable ref.
359 return std::make_unique<VariableExprAST>(IdName);
361 // Call.
362 getNextToken(); // eat (
363 std::vector<std::unique_ptr<ExprAST>> Args;
364 if (CurTok != ')') {
365 while (true) {
366 if (auto Arg = ParseExpression())
367 Args.push_back(std::move(Arg));
368 else
369 return nullptr;
371 if (CurTok == ')')
372 break;
374 if (CurTok != ',')
375 return LogError("Expected ')' or ',' in argument list");
376 getNextToken();
380 // Eat the ')'.
381 getNextToken();
383 return std::make_unique<CallExprAST>(IdName, std::move(Args));
386 /// ifexpr ::= 'if' expression 'then' expression 'else' expression
387 static std::unique_ptr<ExprAST> ParseIfExpr() {
388 getNextToken(); // eat the if.
390 // condition.
391 auto Cond = ParseExpression();
392 if (!Cond)
393 return nullptr;
395 if (CurTok != tok_then)
396 return LogError("expected then");
397 getNextToken(); // eat the then
399 auto Then = ParseExpression();
400 if (!Then)
401 return nullptr;
403 if (CurTok != tok_else)
404 return LogError("expected else");
406 getNextToken();
408 auto Else = ParseExpression();
409 if (!Else)
410 return nullptr;
412 return std::make_unique<IfExprAST>(std::move(Cond), std::move(Then),
413 std::move(Else));
416 /// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression
417 static std::unique_ptr<ExprAST> ParseForExpr() {
418 getNextToken(); // eat the for.
420 if (CurTok != tok_identifier)
421 return LogError("expected identifier after for");
423 std::string IdName = IdentifierStr;
424 getNextToken(); // eat identifier.
426 if (CurTok != '=')
427 return LogError("expected '=' after for");
428 getNextToken(); // eat '='.
430 auto Start = ParseExpression();
431 if (!Start)
432 return nullptr;
433 if (CurTok != ',')
434 return LogError("expected ',' after for start value");
435 getNextToken();
437 auto End = ParseExpression();
438 if (!End)
439 return nullptr;
441 // The step value is optional.
442 std::unique_ptr<ExprAST> Step;
443 if (CurTok == ',') {
444 getNextToken();
445 Step = ParseExpression();
446 if (!Step)
447 return nullptr;
450 if (CurTok != tok_in)
451 return LogError("expected 'in' after for");
452 getNextToken(); // eat 'in'.
454 auto Body = ParseExpression();
455 if (!Body)
456 return nullptr;
458 return std::make_unique<ForExprAST>(IdName, std::move(Start), std::move(End),
459 std::move(Step), std::move(Body));
462 /// varexpr ::= 'var' identifier ('=' expression)?
463 // (',' identifier ('=' expression)?)* 'in' expression
464 static std::unique_ptr<ExprAST> ParseVarExpr() {
465 getNextToken(); // eat the var.
467 std::vector<std::pair<std::string, std::unique_ptr<ExprAST>>> VarNames;
469 // At least one variable name is required.
470 if (CurTok != tok_identifier)
471 return LogError("expected identifier after var");
473 while (true) {
474 std::string Name = IdentifierStr;
475 getNextToken(); // eat identifier.
477 // Read the optional initializer.
478 std::unique_ptr<ExprAST> Init = nullptr;
479 if (CurTok == '=') {
480 getNextToken(); // eat the '='.
482 Init = ParseExpression();
483 if (!Init)
484 return nullptr;
487 VarNames.push_back(std::make_pair(Name, std::move(Init)));
489 // End of var list, exit loop.
490 if (CurTok != ',')
491 break;
492 getNextToken(); // eat the ','.
494 if (CurTok != tok_identifier)
495 return LogError("expected identifier list after var");
498 // At this point, we have to have 'in'.
499 if (CurTok != tok_in)
500 return LogError("expected 'in' keyword after 'var'");
501 getNextToken(); // eat 'in'.
503 auto Body = ParseExpression();
504 if (!Body)
505 return nullptr;
507 return std::make_unique<VarExprAST>(std::move(VarNames), std::move(Body));
510 /// primary
511 /// ::= identifierexpr
512 /// ::= numberexpr
513 /// ::= parenexpr
514 /// ::= ifexpr
515 /// ::= forexpr
516 /// ::= varexpr
517 static std::unique_ptr<ExprAST> ParsePrimary() {
518 switch (CurTok) {
519 default:
520 return LogError("unknown token when expecting an expression");
521 case tok_identifier:
522 return ParseIdentifierExpr();
523 case tok_number:
524 return ParseNumberExpr();
525 case '(':
526 return ParseParenExpr();
527 case tok_if:
528 return ParseIfExpr();
529 case tok_for:
530 return ParseForExpr();
531 case tok_var:
532 return ParseVarExpr();
536 /// unary
537 /// ::= primary
538 /// ::= '!' unary
539 static std::unique_ptr<ExprAST> ParseUnary() {
540 // If the current token is not an operator, it must be a primary expr.
541 if (!isascii(CurTok) || CurTok == '(' || CurTok == ',')
542 return ParsePrimary();
544 // If this is a unary operator, read it.
545 int Opc = CurTok;
546 getNextToken();
547 if (auto Operand = ParseUnary())
548 return std::make_unique<UnaryExprAST>(Opc, std::move(Operand));
549 return nullptr;
552 /// binoprhs
553 /// ::= ('+' unary)*
554 static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec,
555 std::unique_ptr<ExprAST> LHS) {
556 // If this is a binop, find its precedence.
557 while (true) {
558 int TokPrec = GetTokPrecedence();
560 // If this is a binop that binds at least as tightly as the current binop,
561 // consume it, otherwise we are done.
562 if (TokPrec < ExprPrec)
563 return LHS;
565 // Okay, we know this is a binop.
566 int BinOp = CurTok;
567 getNextToken(); // eat binop
569 // Parse the unary expression after the binary operator.
570 auto RHS = ParseUnary();
571 if (!RHS)
572 return nullptr;
574 // If BinOp binds less tightly with RHS than the operator after RHS, let
575 // the pending operator take RHS as its LHS.
576 int NextPrec = GetTokPrecedence();
577 if (TokPrec < NextPrec) {
578 RHS = ParseBinOpRHS(TokPrec + 1, std::move(RHS));
579 if (!RHS)
580 return nullptr;
583 // Merge LHS/RHS.
584 LHS =
585 std::make_unique<BinaryExprAST>(BinOp, std::move(LHS), std::move(RHS));
589 /// expression
590 /// ::= unary binoprhs
592 static std::unique_ptr<ExprAST> ParseExpression() {
593 auto LHS = ParseUnary();
594 if (!LHS)
595 return nullptr;
597 return ParseBinOpRHS(0, std::move(LHS));
600 /// prototype
601 /// ::= id '(' id* ')'
602 /// ::= binary LETTER number? (id, id)
603 /// ::= unary LETTER (id)
604 static std::unique_ptr<PrototypeAST> ParsePrototype() {
605 std::string FnName;
607 unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.
608 unsigned BinaryPrecedence = 30;
610 switch (CurTok) {
611 default:
612 return LogErrorP("Expected function name in prototype");
613 case tok_identifier:
614 FnName = IdentifierStr;
615 Kind = 0;
616 getNextToken();
617 break;
618 case tok_unary:
619 getNextToken();
620 if (!isascii(CurTok))
621 return LogErrorP("Expected unary operator");
622 FnName = "unary";
623 FnName += (char)CurTok;
624 Kind = 1;
625 getNextToken();
626 break;
627 case tok_binary:
628 getNextToken();
629 if (!isascii(CurTok))
630 return LogErrorP("Expected binary operator");
631 FnName = "binary";
632 FnName += (char)CurTok;
633 Kind = 2;
634 getNextToken();
636 // Read the precedence if present.
637 if (CurTok == tok_number) {
638 if (NumVal < 1 || NumVal > 100)
639 return LogErrorP("Invalid precedecnce: must be 1..100");
640 BinaryPrecedence = (unsigned)NumVal;
641 getNextToken();
643 break;
646 if (CurTok != '(')
647 return LogErrorP("Expected '(' in prototype");
649 std::vector<std::string> ArgNames;
650 while (getNextToken() == tok_identifier)
651 ArgNames.push_back(IdentifierStr);
652 if (CurTok != ')')
653 return LogErrorP("Expected ')' in prototype");
655 // success.
656 getNextToken(); // eat ')'.
658 // Verify right number of names for operator.
659 if (Kind && ArgNames.size() != Kind)
660 return LogErrorP("Invalid number of operands for operator");
662 return std::make_unique<PrototypeAST>(FnName, ArgNames, Kind != 0,
663 BinaryPrecedence);
666 /// definition ::= 'def' prototype expression
667 static std::unique_ptr<FunctionAST> ParseDefinition() {
668 getNextToken(); // eat def.
669 auto Proto = ParsePrototype();
670 if (!Proto)
671 return nullptr;
673 if (auto E = ParseExpression())
674 return std::make_unique<FunctionAST>(std::move(Proto), std::move(E));
675 return nullptr;
678 /// toplevelexpr ::= expression
679 static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
680 if (auto E = ParseExpression()) {
681 // Make an anonymous proto.
682 auto Proto = std::make_unique<PrototypeAST>("__anon_expr",
683 std::vector<std::string>());
684 return std::make_unique<FunctionAST>(std::move(Proto), std::move(E));
686 return nullptr;
689 /// external ::= 'extern' prototype
690 static std::unique_ptr<PrototypeAST> ParseExtern() {
691 getNextToken(); // eat extern.
692 return ParsePrototype();
695 //===----------------------------------------------------------------------===//
696 // Code Generation
697 //===----------------------------------------------------------------------===//
699 static LLVMContext TheContext;
700 static IRBuilder<> Builder(TheContext);
701 static std::unique_ptr<Module> TheModule;
702 static std::map<std::string, AllocaInst *> NamedValues;
703 static std::unique_ptr<KaleidoscopeJIT> TheJIT;
704 static std::map<std::string, std::unique_ptr<PrototypeAST>> FunctionProtos;
706 Value *LogErrorV(const char *Str) {
707 LogError(Str);
708 return nullptr;
711 Function *getFunction(std::string Name) {
712 // First, see if the function has already been added to the current module.
713 if (auto *F = TheModule->getFunction(Name))
714 return F;
716 // If not, check whether we can codegen the declaration from some existing
717 // prototype.
718 auto FI = FunctionProtos.find(Name);
719 if (FI != FunctionProtos.end())
720 return FI->second->codegen();
722 // If no existing prototype exists, return null.
723 return nullptr;
726 /// CreateEntryBlockAlloca - Create an alloca instruction in the entry block of
727 /// the function. This is used for mutable variables etc.
728 static AllocaInst *CreateEntryBlockAlloca(Function *TheFunction,
729 const std::string &VarName) {
730 IRBuilder<> TmpB(&TheFunction->getEntryBlock(),
731 TheFunction->getEntryBlock().begin());
732 return TmpB.CreateAlloca(Type::getDoubleTy(TheContext), nullptr, VarName);
735 Value *NumberExprAST::codegen() {
736 return ConstantFP::get(TheContext, APFloat(Val));
739 Value *VariableExprAST::codegen() {
740 // Look this variable up in the function.
741 Value *V = NamedValues[Name];
742 if (!V)
743 return LogErrorV("Unknown variable name");
745 // Load the value.
746 return Builder.CreateLoad(V, Name.c_str());
749 Value *UnaryExprAST::codegen() {
750 Value *OperandV = Operand->codegen();
751 if (!OperandV)
752 return nullptr;
754 Function *F = getFunction(std::string("unary") + Opcode);
755 if (!F)
756 return LogErrorV("Unknown unary operator");
758 return Builder.CreateCall(F, OperandV, "unop");
761 Value *BinaryExprAST::codegen() {
762 // Special case '=' because we don't want to emit the LHS as an expression.
763 if (Op == '=') {
764 // Assignment requires the LHS to be an identifier.
765 // This assume we're building without RTTI because LLVM builds that way by
766 // default. If you build LLVM with RTTI this can be changed to a
767 // dynamic_cast for automatic error checking.
768 VariableExprAST *LHSE = static_cast<VariableExprAST *>(LHS.get());
769 if (!LHSE)
770 return LogErrorV("destination of '=' must be a variable");
771 // Codegen the RHS.
772 Value *Val = RHS->codegen();
773 if (!Val)
774 return nullptr;
776 // Look up the name.
777 Value *Variable = NamedValues[LHSE->getName()];
778 if (!Variable)
779 return LogErrorV("Unknown variable name");
781 Builder.CreateStore(Val, Variable);
782 return Val;
785 Value *L = LHS->codegen();
786 Value *R = RHS->codegen();
787 if (!L || !R)
788 return nullptr;
790 switch (Op) {
791 case '+':
792 return Builder.CreateFAdd(L, R, "addtmp");
793 case '-':
794 return Builder.CreateFSub(L, R, "subtmp");
795 case '*':
796 return Builder.CreateFMul(L, R, "multmp");
797 case '<':
798 L = Builder.CreateFCmpULT(L, R, "cmptmp");
799 // Convert bool 0/1 to double 0.0 or 1.0
800 return Builder.CreateUIToFP(L, Type::getDoubleTy(TheContext), "booltmp");
801 default:
802 break;
805 // If it wasn't a builtin binary operator, it must be a user defined one. Emit
806 // a call to it.
807 Function *F = getFunction(std::string("binary") + Op);
808 assert(F && "binary operator not found!");
810 Value *Ops[] = {L, R};
811 return Builder.CreateCall(F, Ops, "binop");
814 Value *CallExprAST::codegen() {
815 // Look up the name in the global module table.
816 Function *CalleeF = getFunction(Callee);
817 if (!CalleeF)
818 return LogErrorV("Unknown function referenced");
820 // If argument mismatch error.
821 if (CalleeF->arg_size() != Args.size())
822 return LogErrorV("Incorrect # arguments passed");
824 std::vector<Value *> ArgsV;
825 for (unsigned i = 0, e = Args.size(); i != e; ++i) {
826 ArgsV.push_back(Args[i]->codegen());
827 if (!ArgsV.back())
828 return nullptr;
831 return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
834 Value *IfExprAST::codegen() {
835 Value *CondV = Cond->codegen();
836 if (!CondV)
837 return nullptr;
839 // Convert condition to a bool by comparing equal to 0.0.
840 CondV = Builder.CreateFCmpONE(
841 CondV, ConstantFP::get(TheContext, APFloat(0.0)), "ifcond");
843 Function *TheFunction = Builder.GetInsertBlock()->getParent();
845 // Create blocks for the then and else cases. Insert the 'then' block at the
846 // end of the function.
847 BasicBlock *ThenBB = BasicBlock::Create(TheContext, "then", TheFunction);
848 BasicBlock *ElseBB = BasicBlock::Create(TheContext, "else");
849 BasicBlock *MergeBB = BasicBlock::Create(TheContext, "ifcont");
851 Builder.CreateCondBr(CondV, ThenBB, ElseBB);
853 // Emit then value.
854 Builder.SetInsertPoint(ThenBB);
856 Value *ThenV = Then->codegen();
857 if (!ThenV)
858 return nullptr;
860 Builder.CreateBr(MergeBB);
861 // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
862 ThenBB = Builder.GetInsertBlock();
864 // Emit else block.
865 TheFunction->getBasicBlockList().push_back(ElseBB);
866 Builder.SetInsertPoint(ElseBB);
868 Value *ElseV = Else->codegen();
869 if (!ElseV)
870 return nullptr;
872 Builder.CreateBr(MergeBB);
873 // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
874 ElseBB = Builder.GetInsertBlock();
876 // Emit merge block.
877 TheFunction->getBasicBlockList().push_back(MergeBB);
878 Builder.SetInsertPoint(MergeBB);
879 PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(TheContext), 2, "iftmp");
881 PN->addIncoming(ThenV, ThenBB);
882 PN->addIncoming(ElseV, ElseBB);
883 return PN;
886 // Output for-loop as:
887 // var = alloca double
888 // ...
889 // start = startexpr
890 // store start -> var
891 // goto loop
892 // loop:
893 // ...
894 // bodyexpr
895 // ...
896 // loopend:
897 // step = stepexpr
898 // endcond = endexpr
900 // curvar = load var
901 // nextvar = curvar + step
902 // store nextvar -> var
903 // br endcond, loop, endloop
904 // outloop:
905 Value *ForExprAST::codegen() {
906 Function *TheFunction = Builder.GetInsertBlock()->getParent();
908 // Create an alloca for the variable in the entry block.
909 AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
911 // Emit the start code first, without 'variable' in scope.
912 Value *StartVal = Start->codegen();
913 if (!StartVal)
914 return nullptr;
916 // Store the value into the alloca.
917 Builder.CreateStore(StartVal, Alloca);
919 // Make the new basic block for the loop header, inserting after current
920 // block.
921 BasicBlock *LoopBB = BasicBlock::Create(TheContext, "loop", TheFunction);
923 // Insert an explicit fall through from the current block to the LoopBB.
924 Builder.CreateBr(LoopBB);
926 // Start insertion in LoopBB.
927 Builder.SetInsertPoint(LoopBB);
929 // Within the loop, the variable is defined equal to the PHI node. If it
930 // shadows an existing variable, we have to restore it, so save it now.
931 AllocaInst *OldVal = NamedValues[VarName];
932 NamedValues[VarName] = Alloca;
934 // Emit the body of the loop. This, like any other expr, can change the
935 // current BB. Note that we ignore the value computed by the body, but don't
936 // allow an error.
937 if (!Body->codegen())
938 return nullptr;
940 // Emit the step value.
941 Value *StepVal = nullptr;
942 if (Step) {
943 StepVal = Step->codegen();
944 if (!StepVal)
945 return nullptr;
946 } else {
947 // If not specified, use 1.0.
948 StepVal = ConstantFP::get(TheContext, APFloat(1.0));
951 // Compute the end condition.
952 Value *EndCond = End->codegen();
953 if (!EndCond)
954 return nullptr;
956 // Reload, increment, and restore the alloca. This handles the case where
957 // the body of the loop mutates the variable.
958 Value *CurVar = Builder.CreateLoad(Alloca, VarName.c_str());
959 Value *NextVar = Builder.CreateFAdd(CurVar, StepVal, "nextvar");
960 Builder.CreateStore(NextVar, Alloca);
962 // Convert condition to a bool by comparing equal to 0.0.
963 EndCond = Builder.CreateFCmpONE(
964 EndCond, ConstantFP::get(TheContext, APFloat(0.0)), "loopcond");
966 // Create the "after loop" block and insert it.
967 BasicBlock *AfterBB =
968 BasicBlock::Create(TheContext, "afterloop", TheFunction);
970 // Insert the conditional branch into the end of LoopEndBB.
971 Builder.CreateCondBr(EndCond, LoopBB, AfterBB);
973 // Any new code will be inserted in AfterBB.
974 Builder.SetInsertPoint(AfterBB);
976 // Restore the unshadowed variable.
977 if (OldVal)
978 NamedValues[VarName] = OldVal;
979 else
980 NamedValues.erase(VarName);
982 // for expr always returns 0.0.
983 return Constant::getNullValue(Type::getDoubleTy(TheContext));
986 Value *VarExprAST::codegen() {
987 std::vector<AllocaInst *> OldBindings;
989 Function *TheFunction = Builder.GetInsertBlock()->getParent();
991 // Register all variables and emit their initializer.
992 for (unsigned i = 0, e = VarNames.size(); i != e; ++i) {
993 const std::string &VarName = VarNames[i].first;
994 ExprAST *Init = VarNames[i].second.get();
996 // Emit the initializer before adding the variable to scope, this prevents
997 // the initializer from referencing the variable itself, and permits stuff
998 // like this:
999 // var a = 1 in
1000 // var a = a in ... # refers to outer 'a'.
1001 Value *InitVal;
1002 if (Init) {
1003 InitVal = Init->codegen();
1004 if (!InitVal)
1005 return nullptr;
1006 } else { // If not specified, use 0.0.
1007 InitVal = ConstantFP::get(TheContext, APFloat(0.0));
1010 AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
1011 Builder.CreateStore(InitVal, Alloca);
1013 // Remember the old variable binding so that we can restore the binding when
1014 // we unrecurse.
1015 OldBindings.push_back(NamedValues[VarName]);
1017 // Remember this binding.
1018 NamedValues[VarName] = Alloca;
1021 // Codegen the body, now that all vars are in scope.
1022 Value *BodyVal = Body->codegen();
1023 if (!BodyVal)
1024 return nullptr;
1026 // Pop all our variables from scope.
1027 for (unsigned i = 0, e = VarNames.size(); i != e; ++i)
1028 NamedValues[VarNames[i].first] = OldBindings[i];
1030 // Return the body computation.
1031 return BodyVal;
1034 Function *PrototypeAST::codegen() {
1035 // Make the function type: double(double,double) etc.
1036 std::vector<Type *> Doubles(Args.size(), Type::getDoubleTy(TheContext));
1037 FunctionType *FT =
1038 FunctionType::get(Type::getDoubleTy(TheContext), Doubles, false);
1040 Function *F =
1041 Function::Create(FT, Function::ExternalLinkage, Name, TheModule.get());
1043 // Set names for all arguments.
1044 unsigned Idx = 0;
1045 for (auto &Arg : F->args())
1046 Arg.setName(Args[Idx++]);
1048 return F;
1051 Function *FunctionAST::codegen() {
1052 // Transfer ownership of the prototype to the FunctionProtos map, but keep a
1053 // reference to it for use below.
1054 auto &P = *Proto;
1055 FunctionProtos[Proto->getName()] = std::move(Proto);
1056 Function *TheFunction = getFunction(P.getName());
1057 if (!TheFunction)
1058 return nullptr;
1060 // If this is an operator, install it.
1061 if (P.isBinaryOp())
1062 BinopPrecedence[P.getOperatorName()] = P.getBinaryPrecedence();
1064 // Create a new basic block to start insertion into.
1065 BasicBlock *BB = BasicBlock::Create(TheContext, "entry", TheFunction);
1066 Builder.SetInsertPoint(BB);
1068 // Record the function arguments in the NamedValues map.
1069 NamedValues.clear();
1070 for (auto &Arg : TheFunction->args()) {
1071 // Create an alloca for this variable.
1072 AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, Arg.getName());
1074 // Store the initial value into the alloca.
1075 Builder.CreateStore(&Arg, Alloca);
1077 // Add arguments to variable symbol table.
1078 NamedValues[Arg.getName()] = Alloca;
1081 if (Value *RetVal = Body->codegen()) {
1082 // Finish off the function.
1083 Builder.CreateRet(RetVal);
1085 // Validate the generated code, checking for consistency.
1086 verifyFunction(*TheFunction);
1088 return TheFunction;
1091 // Error reading body, remove function.
1092 TheFunction->eraseFromParent();
1094 if (P.isBinaryOp())
1095 BinopPrecedence.erase(P.getOperatorName());
1096 return nullptr;
1099 //===----------------------------------------------------------------------===//
1100 // Top-Level parsing and JIT Driver
1101 //===----------------------------------------------------------------------===//
1103 static void InitializeModule() {
1104 // Open a new module.
1105 TheModule = std::make_unique<Module>("my cool jit", TheContext);
1106 TheModule->setDataLayout(TheJIT->getTargetMachine().createDataLayout());
1109 static void HandleDefinition() {
1110 if (auto FnAST = ParseDefinition()) {
1111 if (auto *FnIR = FnAST->codegen()) {
1112 fprintf(stderr, "Read function definition:");
1113 FnIR->print(errs());
1114 fprintf(stderr, "\n");
1115 TheJIT->addModule(std::move(TheModule));
1116 InitializeModule();
1118 } else {
1119 // Skip token for error recovery.
1120 getNextToken();
1124 static void HandleExtern() {
1125 if (auto ProtoAST = ParseExtern()) {
1126 if (auto *FnIR = ProtoAST->codegen()) {
1127 fprintf(stderr, "Read extern: ");
1128 FnIR->print(errs());
1129 fprintf(stderr, "\n");
1130 FunctionProtos[ProtoAST->getName()] = std::move(ProtoAST);
1132 } else {
1133 // Skip token for error recovery.
1134 getNextToken();
1138 static void HandleTopLevelExpression() {
1139 // Evaluate a top-level expression into an anonymous function.
1140 if (auto FnAST = ParseTopLevelExpr()) {
1141 if (FnAST->codegen()) {
1142 // JIT the module containing the anonymous expression, keeping a handle so
1143 // we can free it later.
1144 auto H = TheJIT->addModule(std::move(TheModule));
1145 InitializeModule();
1147 // Search the JIT for the __anon_expr symbol.
1148 auto ExprSymbol = TheJIT->findSymbol("__anon_expr");
1149 assert(ExprSymbol && "Function not found");
1151 // Get the symbol's address and cast it to the right type (takes no
1152 // arguments, returns a double) so we can call it as a native function.
1153 double (*FP)() = (double (*)())(intptr_t)cantFail(ExprSymbol.getAddress());
1154 fprintf(stderr, "Evaluated to %f\n", FP());
1156 // Delete the anonymous expression module from the JIT.
1157 TheJIT->removeModule(H);
1159 } else {
1160 // Skip token for error recovery.
1161 getNextToken();
1165 /// top ::= definition | external | expression | ';'
1166 static void MainLoop() {
1167 while (true) {
1168 fprintf(stderr, "ready> ");
1169 switch (CurTok) {
1170 case tok_eof:
1171 return;
1172 case ';': // ignore top-level semicolons.
1173 getNextToken();
1174 break;
1175 case tok_def:
1176 HandleDefinition();
1177 break;
1178 case tok_extern:
1179 HandleExtern();
1180 break;
1181 default:
1182 HandleTopLevelExpression();
1183 break;
1188 //===----------------------------------------------------------------------===//
1189 // "Library" functions that can be "extern'd" from user code.
1190 //===----------------------------------------------------------------------===//
1192 /// putchard - putchar that takes a double and returns 0.
1193 extern "C" double putchard(double X) {
1194 fputc((char)X, stderr);
1195 return 0;
1198 /// printd - printf that takes a double prints it as "%f\n", returning 0.
1199 extern "C" double printd(double X) {
1200 fprintf(stderr, "%f\n", X);
1201 return 0;
1204 //===----------------------------------------------------------------------===//
1205 // Main driver code.
1206 //===----------------------------------------------------------------------===//
1208 int main() {
1209 InitializeNativeTarget();
1210 InitializeNativeTargetAsmPrinter();
1211 InitializeNativeTargetAsmParser();
1213 // Install standard binary operators.
1214 // 1 is lowest precedence.
1215 BinopPrecedence['='] = 2;
1216 BinopPrecedence['<'] = 10;
1217 BinopPrecedence['+'] = 20;
1218 BinopPrecedence['-'] = 20;
1219 BinopPrecedence['*'] = 40; // highest.
1221 // Prime the first token.
1222 fprintf(stderr, "ready> ");
1223 getNextToken();
1225 TheJIT = std::make_unique<KaleidoscopeJIT>();
1227 InitializeModule();
1229 // Run the main "interpreter loop" now.
1230 MainLoop();
1232 return 0;