1 #include "../include/KaleidoscopeJIT.h"
2 #include "llvm/ADT/APFloat.h"
3 #include "llvm/ADT/STLExtras.h"
4 #include "llvm/IR/BasicBlock.h"
5 #include "llvm/IR/Constants.h"
6 #include "llvm/IR/DerivedTypes.h"
7 #include "llvm/IR/Function.h"
8 #include "llvm/IR/IRBuilder.h"
9 #include "llvm/IR/LLVMContext.h"
10 #include "llvm/IR/LegacyPassManager.h"
11 #include "llvm/IR/Module.h"
12 #include "llvm/IR/Type.h"
13 #include "llvm/IR/Verifier.h"
14 #include "llvm/Support/TargetSelect.h"
15 #include "llvm/Target/TargetMachine.h"
16 #include "llvm/Transforms/InstCombine/InstCombine.h"
17 #include "llvm/Transforms/Scalar.h"
18 #include "llvm/Transforms/Scalar/GVN.h"
19 #include <algorithm>
20 #include <cassert>
21 #include <cctype>
22 #include <cstdint>
23 #include <cstdio>
24 #include <cstdlib>
25 #include <map>
26 #include <memory>
27 #include <string>
28 #include <vector>
29
30 using namespace llvm;
31 using namespace llvm::orc;
32
33 //===----------------------------------------------------------------------===//
34 // Lexer
35 //===----------------------------------------------------------------------===//
36
37 // The lexer returns tokens [0-255] if it is an unknown character, otherwise one
38 // of these for known things.
39 enum Token {
40 tok_eof = -1,
41
42 // commands
43 tok_def = -2,
44 tok_extern = -3,
45
46 // primary
47 tok_identifier = -4,
48 tok_number = -5
49 };
50
51 static std::string IdentifierStr; // Filled in if tok_identifier
52 static double NumVal; // Filled in if tok_number
53
54 /// gettok - Return the next token from standard input.
gettok()55 static int gettok() {
56 static int LastChar = ' ';
57
58 // Skip any whitespace.
59 while (isspace(LastChar))
60 LastChar = getchar();
61
62 if (isalpha(LastChar)) { // identifier: [a-zA-Z][a-zA-Z0-9]*
63 IdentifierStr = LastChar;
64 while (isalnum((LastChar = getchar())))
65 IdentifierStr += LastChar;
66
67 if (IdentifierStr == "def")
68 return tok_def;
69 if (IdentifierStr == "extern")
70 return tok_extern;
71 return tok_identifier;
72 }
73
74 if (isdigit(LastChar) || LastChar == '.') { // Number: [0-9.]+
75 std::string NumStr;
76 do {
77 NumStr += LastChar;
78 LastChar = getchar();
79 } while (isdigit(LastChar) || LastChar == '.');
80
81 NumVal = strtod(NumStr.c_str(), nullptr);
82 return tok_number;
83 }
84
85 if (LastChar == '#') {
86 // Comment until end of line.
87 do
88 LastChar = getchar();
89 while (LastChar != EOF && LastChar != '\n' && LastChar != '\r');
90
91 if (LastChar != EOF)
92 return gettok();
93 }
94
95 // Check for end of file. Don't eat the EOF.
96 if (LastChar == EOF)
97 return tok_eof;
98
99 // Otherwise, just return the character as its ascii value.
100 int ThisChar = LastChar;
101 LastChar = getchar();
102 return ThisChar;
103 }
104
105 //===----------------------------------------------------------------------===//
106 // Abstract Syntax Tree (aka Parse Tree)
107 //===----------------------------------------------------------------------===//
108
109 namespace {
110
111 /// ExprAST - Base class for all expression nodes.
112 class ExprAST {
113 public:
114 virtual ~ExprAST() = default;
115
116 virtual Value *codegen() = 0;
117 };
118
119 /// NumberExprAST - Expression class for numeric literals like "1.0".
120 class NumberExprAST : public ExprAST {
121 double Val;
122
123 public:
NumberExprAST(double Val)124 NumberExprAST(double Val) : Val(Val) {}
125
126 Value *codegen() override;
127 };
128
129 /// VariableExprAST - Expression class for referencing a variable, like "a".
130 class VariableExprAST : public ExprAST {
131 std::string Name;
132
133 public:
VariableExprAST(const std::string & Name)134 VariableExprAST(const std::string &Name) : Name(Name) {}
135
136 Value *codegen() override;
137 };
138
139 /// BinaryExprAST - Expression class for a binary operator.
140 class BinaryExprAST : public ExprAST {
141 char Op;
142 std::unique_ptr<ExprAST> LHS, RHS;
143
144 public:
BinaryExprAST(char Op,std::unique_ptr<ExprAST> LHS,std::unique_ptr<ExprAST> RHS)145 BinaryExprAST(char Op, std::unique_ptr<ExprAST> LHS,
146 std::unique_ptr<ExprAST> RHS)
147 : Op(Op), LHS(std::move(LHS)), RHS(std::move(RHS)) {}
148
149 Value *codegen() override;
150 };
151
152 /// CallExprAST - Expression class for function calls.
153 class CallExprAST : public ExprAST {
154 std::string Callee;
155 std::vector<std::unique_ptr<ExprAST>> Args;
156
157 public:
CallExprAST(const std::string & Callee,std::vector<std::unique_ptr<ExprAST>> Args)158 CallExprAST(const std::string &Callee,
159 std::vector<std::unique_ptr<ExprAST>> Args)
160 : Callee(Callee), Args(std::move(Args)) {}
161
162 Value *codegen() override;
163 };
164
165 /// PrototypeAST - This class represents the "prototype" for a function,
166 /// which captures its name, and its argument names (thus implicitly the number
167 /// of arguments the function takes).
168 class PrototypeAST {
169 std::string Name;
170 std::vector<std::string> Args;
171
172 public:
PrototypeAST(const std::string & Name,std::vector<std::string> Args)173 PrototypeAST(const std::string &Name, std::vector<std::string> Args)
174 : Name(Name), Args(std::move(Args)) {}
175
176 Function *codegen();
getName() const177 const std::string &getName() const { return Name; }
178 };
179
180 /// FunctionAST - This class represents a function definition itself.
181 class FunctionAST {
182 std::unique_ptr<PrototypeAST> Proto;
183 std::unique_ptr<ExprAST> Body;
184
185 public:
FunctionAST(std::unique_ptr<PrototypeAST> Proto,std::unique_ptr<ExprAST> Body)186 FunctionAST(std::unique_ptr<PrototypeAST> Proto,
187 std::unique_ptr<ExprAST> Body)
188 : Proto(std::move(Proto)), Body(std::move(Body)) {}
189
190 Function *codegen();
191 };
192
193 } // end anonymous namespace
194
195 //===----------------------------------------------------------------------===//
196 // Parser
197 //===----------------------------------------------------------------------===//
198
199 /// CurTok/getNextToken - Provide a simple token buffer. CurTok is the current
200 /// token the parser is looking at. getNextToken reads another token from the
201 /// lexer and updates CurTok with its results.
202 static int CurTok;
getNextToken()203 static int getNextToken() { return CurTok = gettok(); }
204
205 /// BinopPrecedence - This holds the precedence for each binary operator that is
206 /// defined.
207 static std::map<char, int> BinopPrecedence;
208
209 /// GetTokPrecedence - Get the precedence of the pending binary operator token.
GetTokPrecedence()210 static int GetTokPrecedence() {
211 if (!isascii(CurTok))
212 return -1;
213
214 // Make sure it's a declared binop.
215 int TokPrec = BinopPrecedence[CurTok];
216 if (TokPrec <= 0)
217 return -1;
218 return TokPrec;
219 }
220
221 /// LogError* - These are little helper functions for error handling.
LogError(const char * Str)222 std::unique_ptr<ExprAST> LogError(const char *Str) {
223 fprintf(stderr, "Error: %s\n", Str);
224 return nullptr;
225 }
226
LogErrorP(const char * Str)227 std::unique_ptr<PrototypeAST> LogErrorP(const char *Str) {
228 LogError(Str);
229 return nullptr;
230 }
231
232 static std::unique_ptr<ExprAST> ParseExpression();
233
234 /// numberexpr ::= number
ParseNumberExpr()235 static std::unique_ptr<ExprAST> ParseNumberExpr() {
236 auto Result = std::make_unique<NumberExprAST>(NumVal);
237 getNextToken(); // consume the number
238 return std::move(Result);
239 }
240
241 /// parenexpr ::= '(' expression ')'
ParseParenExpr()242 static std::unique_ptr<ExprAST> ParseParenExpr() {
243 getNextToken(); // eat (.
244 auto V = ParseExpression();
245 if (!V)
246 return nullptr;
247
248 if (CurTok != ')')
249 return LogError("expected ')'");
250 getNextToken(); // eat ).
251 return V;
252 }
253
254 /// identifierexpr
255 /// ::= identifier
256 /// ::= identifier '(' expression* ')'
ParseIdentifierExpr()257 static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
258 std::string IdName = IdentifierStr;
259
260 getNextToken(); // eat identifier.
261
262 if (CurTok != '(') // Simple variable ref.
263 return std::make_unique<VariableExprAST>(IdName);
264
265 // Call.
266 getNextToken(); // eat (
267 std::vector<std::unique_ptr<ExprAST>> Args;
268 if (CurTok != ')') {
269 while (true) {
270 if (auto Arg = ParseExpression())
271 Args.push_back(std::move(Arg));
272 else
273 return nullptr;
274
275 if (CurTok == ')')
276 break;
277
278 if (CurTok != ',')
279 return LogError("Expected ')' or ',' in argument list");
280 getNextToken();
281 }
282 }
283
284 // Eat the ')'.
285 getNextToken();
286
287 return std::make_unique<CallExprAST>(IdName, std::move(Args));
288 }
289
290 /// primary
291 /// ::= identifierexpr
292 /// ::= numberexpr
293 /// ::= parenexpr
ParsePrimary()294 static std::unique_ptr<ExprAST> ParsePrimary() {
295 switch (CurTok) {
296 default:
297 return LogError("unknown token when expecting an expression");
298 case tok_identifier:
299 return ParseIdentifierExpr();
300 case tok_number:
301 return ParseNumberExpr();
302 case '(':
303 return ParseParenExpr();
304 }
305 }
306
307 /// binoprhs
308 /// ::= ('+' primary)*
ParseBinOpRHS(int ExprPrec,std::unique_ptr<ExprAST> LHS)309 static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec,
310 std::unique_ptr<ExprAST> LHS) {
311 // If this is a binop, find its precedence.
312 while (true) {
313 int TokPrec = GetTokPrecedence();
314
315 // If this is a binop that binds at least as tightly as the current binop,
316 // consume it, otherwise we are done.
317 if (TokPrec < ExprPrec)
318 return LHS;
319
320 // Okay, we know this is a binop.
321 int BinOp = CurTok;
322 getNextToken(); // eat binop
323
324 // Parse the primary expression after the binary operator.
325 auto RHS = ParsePrimary();
326 if (!RHS)
327 return nullptr;
328
329 // If BinOp binds less tightly with RHS than the operator after RHS, let
330 // the pending operator take RHS as its LHS.
331 int NextPrec = GetTokPrecedence();
332 if (TokPrec < NextPrec) {
333 RHS = ParseBinOpRHS(TokPrec + 1, std::move(RHS));
334 if (!RHS)
335 return nullptr;
336 }
337
338 // Merge LHS/RHS.
339 LHS =
340 std::make_unique<BinaryExprAST>(BinOp, std::move(LHS), std::move(RHS));
341 }
342 }
343
344 /// expression
345 /// ::= primary binoprhs
346 ///
ParseExpression()347 static std::unique_ptr<ExprAST> ParseExpression() {
348 auto LHS = ParsePrimary();
349 if (!LHS)
350 return nullptr;
351
352 return ParseBinOpRHS(0, std::move(LHS));
353 }
354
355 /// prototype
356 /// ::= id '(' id* ')'
ParsePrototype()357 static std::unique_ptr<PrototypeAST> ParsePrototype() {
358 if (CurTok != tok_identifier)
359 return LogErrorP("Expected function name in prototype");
360
361 std::string FnName = IdentifierStr;
362 getNextToken();
363
364 if (CurTok != '(')
365 return LogErrorP("Expected '(' in prototype");
366
367 std::vector<std::string> ArgNames;
368 while (getNextToken() == tok_identifier)
369 ArgNames.push_back(IdentifierStr);
370 if (CurTok != ')')
371 return LogErrorP("Expected ')' in prototype");
372
373 // success.
374 getNextToken(); // eat ')'.
375
376 return std::make_unique<PrototypeAST>(FnName, std::move(ArgNames));
377 }
378
379 /// definition ::= 'def' prototype expression
ParseDefinition()380 static std::unique_ptr<FunctionAST> ParseDefinition() {
381 getNextToken(); // eat def.
382 auto Proto = ParsePrototype();
383 if (!Proto)
384 return nullptr;
385
386 if (auto E = ParseExpression())
387 return std::make_unique<FunctionAST>(std::move(Proto), std::move(E));
388 return nullptr;
389 }
390
391 /// toplevelexpr ::= expression
ParseTopLevelExpr()392 static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
393 if (auto E = ParseExpression()) {
394 // Make an anonymous proto.
395 auto Proto = std::make_unique<PrototypeAST>("__anon_expr",
396 std::vector<std::string>());
397 return std::make_unique<FunctionAST>(std::move(Proto), std::move(E));
398 }
399 return nullptr;
400 }
401
402 /// external ::= 'extern' prototype
ParseExtern()403 static std::unique_ptr<PrototypeAST> ParseExtern() {
404 getNextToken(); // eat extern.
405 return ParsePrototype();
406 }
407
408 //===----------------------------------------------------------------------===//
409 // Code Generation
410 //===----------------------------------------------------------------------===//
411
412 static LLVMContext TheContext;
413 static IRBuilder<> Builder(TheContext);
414 static std::unique_ptr<Module> TheModule;
415 static std::map<std::string, Value *> NamedValues;
416 static std::unique_ptr<legacy::FunctionPassManager> TheFPM;
417 static std::unique_ptr<KaleidoscopeJIT> TheJIT;
418 static std::map<std::string, std::unique_ptr<PrototypeAST>> FunctionProtos;
419
LogErrorV(const char * Str)420 Value *LogErrorV(const char *Str) {
421 LogError(Str);
422 return nullptr;
423 }
424
getFunction(std::string Name)425 Function *getFunction(std::string Name) {
426 // First, see if the function has already been added to the current module.
427 if (auto *F = TheModule->getFunction(Name))
428 return F;
429
430 // If not, check whether we can codegen the declaration from some existing
431 // prototype.
432 auto FI = FunctionProtos.find(Name);
433 if (FI != FunctionProtos.end())
434 return FI->second->codegen();
435
436 // If no existing prototype exists, return null.
437 return nullptr;
438 }
439
codegen()440 Value *NumberExprAST::codegen() {
441 return ConstantFP::get(TheContext, APFloat(Val));
442 }
443
codegen()444 Value *VariableExprAST::codegen() {
445 // Look this variable up in the function.
446 Value *V = NamedValues[Name];
447 if (!V)
448 return LogErrorV("Unknown variable name");
449 return V;
450 }
451
codegen()452 Value *BinaryExprAST::codegen() {
453 Value *L = LHS->codegen();
454 Value *R = RHS->codegen();
455 if (!L || !R)
456 return nullptr;
457
458 switch (Op) {
459 case '+':
460 return Builder.CreateFAdd(L, R, "addtmp");
461 case '-':
462 return Builder.CreateFSub(L, R, "subtmp");
463 case '*':
464 return Builder.CreateFMul(L, R, "multmp");
465 case '<':
466 L = Builder.CreateFCmpULT(L, R, "cmptmp");
467 // Convert bool 0/1 to double 0.0 or 1.0
468 return Builder.CreateUIToFP(L, Type::getDoubleTy(TheContext), "booltmp");
469 default:
470 return LogErrorV("invalid binary operator");
471 }
472 }
473
codegen()474 Value *CallExprAST::codegen() {
475 // Look up the name in the global module table.
476 Function *CalleeF = getFunction(Callee);
477 if (!CalleeF)
478 return LogErrorV("Unknown function referenced");
479
480 // If argument mismatch error.
481 if (CalleeF->arg_size() != Args.size())
482 return LogErrorV("Incorrect # arguments passed");
483
484 std::vector<Value *> ArgsV;
485 for (unsigned i = 0, e = Args.size(); i != e; ++i) {
486 ArgsV.push_back(Args[i]->codegen());
487 if (!ArgsV.back())
488 return nullptr;
489 }
490
491 return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
492 }
493
codegen()494 Function *PrototypeAST::codegen() {
495 // Make the function type: double(double,double) etc.
496 std::vector<Type *> Doubles(Args.size(), Type::getDoubleTy(TheContext));
497 FunctionType *FT =
498 FunctionType::get(Type::getDoubleTy(TheContext), Doubles, false);
499
500 Function *F =
501 Function::Create(FT, Function::ExternalLinkage, Name, TheModule.get());
502
503 // Set names for all arguments.
504 unsigned Idx = 0;
505 for (auto &Arg : F->args())
506 Arg.setName(Args[Idx++]);
507
508 return F;
509 }
510
codegen()511 Function *FunctionAST::codegen() {
512 // Transfer ownership of the prototype to the FunctionProtos map, but keep a
513 // reference to it for use below.
514 auto &P = *Proto;
515 FunctionProtos[Proto->getName()] = std::move(Proto);
516 Function *TheFunction = getFunction(P.getName());
517 if (!TheFunction)
518 return nullptr;
519
520 // Create a new basic block to start insertion into.
521 BasicBlock *BB = BasicBlock::Create(TheContext, "entry", TheFunction);
522 Builder.SetInsertPoint(BB);
523
524 // Record the function arguments in the NamedValues map.
525 NamedValues.clear();
526 for (auto &Arg : TheFunction->args())
527 NamedValues[std::string(Arg.getName())] = &Arg;
528
529 if (Value *RetVal = Body->codegen()) {
530 // Finish off the function.
531 Builder.CreateRet(RetVal);
532
533 // Validate the generated code, checking for consistency.
534 verifyFunction(*TheFunction);
535
536 // Run the optimizer on the function.
537 TheFPM->run(*TheFunction);
538
539 return TheFunction;
540 }
541
542 // Error reading body, remove function.
543 TheFunction->eraseFromParent();
544 return nullptr;
545 }
546
547 //===----------------------------------------------------------------------===//
548 // Top-Level parsing and JIT Driver
549 //===----------------------------------------------------------------------===//
550
InitializeModuleAndPassManager()551 static void InitializeModuleAndPassManager() {
552 // Open a new module.
553 TheModule = std::make_unique<Module>("my cool jit", TheContext);
554 TheModule->setDataLayout(TheJIT->getTargetMachine().createDataLayout());
555
556 // Create a new pass manager attached to it.
557 TheFPM = std::make_unique<legacy::FunctionPassManager>(TheModule.get());
558
559 // Do simple "peephole" optimizations and bit-twiddling optzns.
560 TheFPM->add(createInstructionCombiningPass());
561 // Reassociate expressions.
562 TheFPM->add(createReassociatePass());
563 // Eliminate Common SubExpressions.
564 TheFPM->add(createGVNPass());
565 // Simplify the control flow graph (deleting unreachable blocks, etc).
566 TheFPM->add(createCFGSimplificationPass());
567
568 TheFPM->doInitialization();
569 }
570
HandleDefinition()571 static void HandleDefinition() {
572 if (auto FnAST = ParseDefinition()) {
573 if (auto *FnIR = FnAST->codegen()) {
574 fprintf(stderr, "Read function definition:");
575 FnIR->print(errs());
576 fprintf(stderr, "\n");
577 TheJIT->addModule(std::move(TheModule));
578 InitializeModuleAndPassManager();
579 }
580 } else {
581 // Skip token for error recovery.
582 getNextToken();
583 }
584 }
585
HandleExtern()586 static void HandleExtern() {
587 if (auto ProtoAST = ParseExtern()) {
588 if (auto *FnIR = ProtoAST->codegen()) {
589 fprintf(stderr, "Read extern: ");
590 FnIR->print(errs());
591 fprintf(stderr, "\n");
592 FunctionProtos[ProtoAST->getName()] = std::move(ProtoAST);
593 }
594 } else {
595 // Skip token for error recovery.
596 getNextToken();
597 }
598 }
599
HandleTopLevelExpression()600 static void HandleTopLevelExpression() {
601 // Evaluate a top-level expression into an anonymous function.
602 if (auto FnAST = ParseTopLevelExpr()) {
603 if (FnAST->codegen()) {
604 // JIT the module containing the anonymous expression, keeping a handle so
605 // we can free it later.
606 auto H = TheJIT->addModule(std::move(TheModule));
607 InitializeModuleAndPassManager();
608
609 // Search the JIT for the __anon_expr symbol.
610 auto ExprSymbol = TheJIT->findSymbol("__anon_expr");
611 assert(ExprSymbol && "Function not found");
612
613 // Get the symbol's address and cast it to the right type (takes no
614 // arguments, returns a double) so we can call it as a native function.
615 double (*FP)() = (double (*)())(intptr_t)cantFail(ExprSymbol.getAddress());
616 fprintf(stderr, "Evaluated to %f\n", FP());
617
618 // Delete the anonymous expression module from the JIT.
619 TheJIT->removeModule(H);
620 }
621 } else {
622 // Skip token for error recovery.
623 getNextToken();
624 }
625 }
626
627 /// top ::= definition | external | expression | ';'
MainLoop()628 static void MainLoop() {
629 while (true) {
630 fprintf(stderr, "ready> ");
631 switch (CurTok) {
632 case tok_eof:
633 return;
634 case ';': // ignore top-level semicolons.
635 getNextToken();
636 break;
637 case tok_def:
638 HandleDefinition();
639 break;
640 case tok_extern:
641 HandleExtern();
642 break;
643 default:
644 HandleTopLevelExpression();
645 break;
646 }
647 }
648 }
649
650 //===----------------------------------------------------------------------===//
651 // "Library" functions that can be "extern'd" from user code.
652 //===----------------------------------------------------------------------===//
653
654 #ifdef _WIN32
655 #define DLLEXPORT __declspec(dllexport)
656 #else
657 #define DLLEXPORT
658 #endif
659
660 /// putchard - putchar that takes a double and returns 0.
putchard(double X)661 extern "C" DLLEXPORT double putchard(double X) {
662 fputc((char)X, stderr);
663 return 0;
664 }
665
666 /// printd - printf that takes a double prints it as "%f\n", returning 0.
printd(double X)667 extern "C" DLLEXPORT double printd(double X) {
668 fprintf(stderr, "%f\n", X);
669 return 0;
670 }
671
672 //===----------------------------------------------------------------------===//
673 // Main driver code.
674 //===----------------------------------------------------------------------===//
675
main()676 int main() {
677 InitializeNativeTarget();
678 InitializeNativeTargetAsmPrinter();
679 InitializeNativeTargetAsmParser();
680
681 // Install standard binary operators.
682 // 1 is lowest precedence.
683 BinopPrecedence['<'] = 10;
684 BinopPrecedence['+'] = 20;
685 BinopPrecedence['-'] = 20;
686 BinopPrecedence['*'] = 40; // highest.
687
688 // Prime the first token.
689 fprintf(stderr, "ready> ");
690 getNextToken();
691
692 TheJIT = std::make_unique<KaleidoscopeJIT>();
693
694 InitializeModuleAndPassManager();
695
696 // Run the main "interpreter loop" now.
697 MainLoop();
698
699 return 0;
700 }
701