1 #include "llvm/ADT/STLExtras.h"
2 #include "llvm/Analysis/Passes.h"
3 #include "llvm/IR/IRBuilder.h"
4 #include "llvm/IR/LLVMContext.h"
5 #include "llvm/IR/LegacyPassManager.h"
6 #include "llvm/IR/Module.h"
7 #include "llvm/IR/Verifier.h"
8 #include "llvm/Support/TargetSelect.h"
9 #include "llvm/Transforms/Scalar.h"
10 #include <cctype>
11 #include <cstdio>
12 #include <map>
13 #include <string>
14 #include <vector>
15 #include "../include/KaleidoscopeJIT.h"
16
17 using namespace llvm;
18 using namespace llvm::orc;
19
20 //===----------------------------------------------------------------------===//
21 // Lexer
22 //===----------------------------------------------------------------------===//
23
24 // The lexer returns tokens [0-255] if it is an unknown character, otherwise one
25 // of these for known things.
26 enum Token {
27 tok_eof = -1,
28
29 // commands
30 tok_def = -2,
31 tok_extern = -3,
32
33 // primary
34 tok_identifier = -4,
35 tok_number = -5
36 };
37
38 static std::string IdentifierStr; // Filled in if tok_identifier
39 static double NumVal; // Filled in if tok_number
40
41 /// gettok - Return the next token from standard input.
gettok()42 static int gettok() {
43 static int LastChar = ' ';
44
45 // Skip any whitespace.
46 while (isspace(LastChar))
47 LastChar = getchar();
48
49 if (isalpha(LastChar)) { // identifier: [a-zA-Z][a-zA-Z0-9]*
50 IdentifierStr = LastChar;
51 while (isalnum((LastChar = getchar())))
52 IdentifierStr += LastChar;
53
54 if (IdentifierStr == "def")
55 return tok_def;
56 if (IdentifierStr == "extern")
57 return tok_extern;
58 return tok_identifier;
59 }
60
61 if (isdigit(LastChar) || LastChar == '.') { // Number: [0-9.]+
62 std::string NumStr;
63 do {
64 NumStr += LastChar;
65 LastChar = getchar();
66 } while (isdigit(LastChar) || LastChar == '.');
67
68 NumVal = strtod(NumStr.c_str(), nullptr);
69 return tok_number;
70 }
71
72 if (LastChar == '#') {
73 // Comment until end of line.
74 do
75 LastChar = getchar();
76 while (LastChar != EOF && LastChar != '\n' && LastChar != '\r');
77
78 if (LastChar != EOF)
79 return gettok();
80 }
81
82 // Check for end of file. Don't eat the EOF.
83 if (LastChar == EOF)
84 return tok_eof;
85
86 // Otherwise, just return the character as its ascii value.
87 int ThisChar = LastChar;
88 LastChar = getchar();
89 return ThisChar;
90 }
91
92 //===----------------------------------------------------------------------===//
93 // Abstract Syntax Tree (aka Parse Tree)
94 //===----------------------------------------------------------------------===//
95 namespace {
96 /// ExprAST - Base class for all expression nodes.
97 class ExprAST {
98 public:
~ExprAST()99 virtual ~ExprAST() {}
100 virtual Value *codegen() = 0;
101 };
102
103 /// NumberExprAST - Expression class for numeric literals like "1.0".
104 class NumberExprAST : public ExprAST {
105 double Val;
106
107 public:
NumberExprAST(double Val)108 NumberExprAST(double Val) : Val(Val) {}
109 Value *codegen() override;
110 };
111
112 /// VariableExprAST - Expression class for referencing a variable, like "a".
113 class VariableExprAST : public ExprAST {
114 std::string Name;
115
116 public:
VariableExprAST(const std::string & Name)117 VariableExprAST(const std::string &Name) : Name(Name) {}
118 Value *codegen() override;
119 };
120
121 /// BinaryExprAST - Expression class for a binary operator.
122 class BinaryExprAST : public ExprAST {
123 char Op;
124 std::unique_ptr<ExprAST> LHS, RHS;
125
126 public:
BinaryExprAST(char Op,std::unique_ptr<ExprAST> LHS,std::unique_ptr<ExprAST> RHS)127 BinaryExprAST(char Op, std::unique_ptr<ExprAST> LHS,
128 std::unique_ptr<ExprAST> RHS)
129 : Op(Op), LHS(std::move(LHS)), RHS(std::move(RHS)) {}
130 Value *codegen() override;
131 };
132
133 /// CallExprAST - Expression class for function calls.
134 class CallExprAST : public ExprAST {
135 std::string Callee;
136 std::vector<std::unique_ptr<ExprAST>> Args;
137
138 public:
CallExprAST(const std::string & Callee,std::vector<std::unique_ptr<ExprAST>> Args)139 CallExprAST(const std::string &Callee,
140 std::vector<std::unique_ptr<ExprAST>> Args)
141 : Callee(Callee), Args(std::move(Args)) {}
142 Value *codegen() override;
143 };
144
145 /// PrototypeAST - This class represents the "prototype" for a function,
146 /// which captures its name, and its argument names (thus implicitly the number
147 /// of arguments the function takes).
148 class PrototypeAST {
149 std::string Name;
150 std::vector<std::string> Args;
151
152 public:
PrototypeAST(const std::string & Name,std::vector<std::string> Args)153 PrototypeAST(const std::string &Name, std::vector<std::string> Args)
154 : Name(Name), Args(std::move(Args)) {}
155 Function *codegen();
getName() const156 const std::string &getName() const { return Name; }
157 };
158
159 /// FunctionAST - This class represents a function definition itself.
160 class FunctionAST {
161 std::unique_ptr<PrototypeAST> Proto;
162 std::unique_ptr<ExprAST> Body;
163
164 public:
FunctionAST(std::unique_ptr<PrototypeAST> Proto,std::unique_ptr<ExprAST> Body)165 FunctionAST(std::unique_ptr<PrototypeAST> Proto,
166 std::unique_ptr<ExprAST> Body)
167 : Proto(std::move(Proto)), Body(std::move(Body)) {}
168 Function *codegen();
169 };
170 } // end anonymous namespace
171
172 //===----------------------------------------------------------------------===//
173 // Parser
174 //===----------------------------------------------------------------------===//
175
176 /// CurTok/getNextToken - Provide a simple token buffer. CurTok is the current
177 /// token the parser is looking at. getNextToken reads another token from the
178 /// lexer and updates CurTok with its results.
179 static int CurTok;
getNextToken()180 static int getNextToken() { return CurTok = gettok(); }
181
182 /// BinopPrecedence - This holds the precedence for each binary operator that is
183 /// defined.
184 static std::map<char, int> BinopPrecedence;
185
186 /// GetTokPrecedence - Get the precedence of the pending binary operator token.
GetTokPrecedence()187 static int GetTokPrecedence() {
188 if (!isascii(CurTok))
189 return -1;
190
191 // Make sure it's a declared binop.
192 int TokPrec = BinopPrecedence[CurTok];
193 if (TokPrec <= 0)
194 return -1;
195 return TokPrec;
196 }
197
198 /// Error* - These are little helper functions for error handling.
Error(const char * Str)199 std::unique_ptr<ExprAST> Error(const char *Str) {
200 fprintf(stderr, "Error: %s\n", Str);
201 return nullptr;
202 }
203
ErrorP(const char * Str)204 std::unique_ptr<PrototypeAST> ErrorP(const char *Str) {
205 Error(Str);
206 return nullptr;
207 }
208
209 static std::unique_ptr<ExprAST> ParseExpression();
210
211 /// numberexpr ::= number
ParseNumberExpr()212 static std::unique_ptr<ExprAST> ParseNumberExpr() {
213 auto Result = llvm::make_unique<NumberExprAST>(NumVal);
214 getNextToken(); // consume the number
215 return std::move(Result);
216 }
217
218 /// parenexpr ::= '(' expression ')'
ParseParenExpr()219 static std::unique_ptr<ExprAST> ParseParenExpr() {
220 getNextToken(); // eat (.
221 auto V = ParseExpression();
222 if (!V)
223 return nullptr;
224
225 if (CurTok != ')')
226 return Error("expected ')'");
227 getNextToken(); // eat ).
228 return V;
229 }
230
231 /// identifierexpr
232 /// ::= identifier
233 /// ::= identifier '(' expression* ')'
ParseIdentifierExpr()234 static std::unique_ptr<ExprAST> ParseIdentifierExpr() {
235 std::string IdName = IdentifierStr;
236
237 getNextToken(); // eat identifier.
238
239 if (CurTok != '(') // Simple variable ref.
240 return llvm::make_unique<VariableExprAST>(IdName);
241
242 // Call.
243 getNextToken(); // eat (
244 std::vector<std::unique_ptr<ExprAST>> Args;
245 if (CurTok != ')') {
246 while (1) {
247 if (auto Arg = ParseExpression())
248 Args.push_back(std::move(Arg));
249 else
250 return nullptr;
251
252 if (CurTok == ')')
253 break;
254
255 if (CurTok != ',')
256 return Error("Expected ')' or ',' in argument list");
257 getNextToken();
258 }
259 }
260
261 // Eat the ')'.
262 getNextToken();
263
264 return llvm::make_unique<CallExprAST>(IdName, std::move(Args));
265 }
266
267 /// primary
268 /// ::= identifierexpr
269 /// ::= numberexpr
270 /// ::= parenexpr
ParsePrimary()271 static std::unique_ptr<ExprAST> ParsePrimary() {
272 switch (CurTok) {
273 default:
274 return Error("unknown token when expecting an expression");
275 case tok_identifier:
276 return ParseIdentifierExpr();
277 case tok_number:
278 return ParseNumberExpr();
279 case '(':
280 return ParseParenExpr();
281 }
282 }
283
284 /// binoprhs
285 /// ::= ('+' primary)*
ParseBinOpRHS(int ExprPrec,std::unique_ptr<ExprAST> LHS)286 static std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec,
287 std::unique_ptr<ExprAST> LHS) {
288 // If this is a binop, find its precedence.
289 while (1) {
290 int TokPrec = GetTokPrecedence();
291
292 // If this is a binop that binds at least as tightly as the current binop,
293 // consume it, otherwise we are done.
294 if (TokPrec < ExprPrec)
295 return LHS;
296
297 // Okay, we know this is a binop.
298 int BinOp = CurTok;
299 getNextToken(); // eat binop
300
301 // Parse the primary expression after the binary operator.
302 auto RHS = ParsePrimary();
303 if (!RHS)
304 return nullptr;
305
306 // If BinOp binds less tightly with RHS than the operator after RHS, let
307 // the pending operator take RHS as its LHS.
308 int NextPrec = GetTokPrecedence();
309 if (TokPrec < NextPrec) {
310 RHS = ParseBinOpRHS(TokPrec + 1, std::move(RHS));
311 if (!RHS)
312 return nullptr;
313 }
314
315 // Merge LHS/RHS.
316 LHS =
317 llvm::make_unique<BinaryExprAST>(BinOp, std::move(LHS), std::move(RHS));
318 }
319 }
320
321 /// expression
322 /// ::= primary binoprhs
323 ///
ParseExpression()324 static std::unique_ptr<ExprAST> ParseExpression() {
325 auto LHS = ParsePrimary();
326 if (!LHS)
327 return nullptr;
328
329 return ParseBinOpRHS(0, std::move(LHS));
330 }
331
332 /// prototype
333 /// ::= id '(' id* ')'
ParsePrototype()334 static std::unique_ptr<PrototypeAST> ParsePrototype() {
335 if (CurTok != tok_identifier)
336 return ErrorP("Expected function name in prototype");
337
338 std::string FnName = IdentifierStr;
339 getNextToken();
340
341 if (CurTok != '(')
342 return ErrorP("Expected '(' in prototype");
343
344 std::vector<std::string> ArgNames;
345 while (getNextToken() == tok_identifier)
346 ArgNames.push_back(IdentifierStr);
347 if (CurTok != ')')
348 return ErrorP("Expected ')' in prototype");
349
350 // success.
351 getNextToken(); // eat ')'.
352
353 return llvm::make_unique<PrototypeAST>(FnName, std::move(ArgNames));
354 }
355
356 /// definition ::= 'def' prototype expression
ParseDefinition()357 static std::unique_ptr<FunctionAST> ParseDefinition() {
358 getNextToken(); // eat def.
359 auto Proto = ParsePrototype();
360 if (!Proto)
361 return nullptr;
362
363 if (auto E = ParseExpression())
364 return llvm::make_unique<FunctionAST>(std::move(Proto), std::move(E));
365 return nullptr;
366 }
367
368 /// toplevelexpr ::= expression
ParseTopLevelExpr()369 static std::unique_ptr<FunctionAST> ParseTopLevelExpr() {
370 if (auto E = ParseExpression()) {
371 // Make an anonymous proto.
372 auto Proto = llvm::make_unique<PrototypeAST>("__anon_expr",
373 std::vector<std::string>());
374 return llvm::make_unique<FunctionAST>(std::move(Proto), std::move(E));
375 }
376 return nullptr;
377 }
378
379 /// external ::= 'extern' prototype
ParseExtern()380 static std::unique_ptr<PrototypeAST> ParseExtern() {
381 getNextToken(); // eat extern.
382 return ParsePrototype();
383 }
384
385 //===----------------------------------------------------------------------===//
386 // Code Generation
387 //===----------------------------------------------------------------------===//
388
389 static std::unique_ptr<Module> TheModule;
390 static IRBuilder<> Builder(getGlobalContext());
391 static std::map<std::string, Value *> NamedValues;
392 static std::unique_ptr<legacy::FunctionPassManager> TheFPM;
393 static std::unique_ptr<KaleidoscopeJIT> TheJIT;
394 static std::map<std::string, std::unique_ptr<PrototypeAST>> FunctionProtos;
395
ErrorV(const char * Str)396 Value *ErrorV(const char *Str) {
397 Error(Str);
398 return nullptr;
399 }
400
getFunction(std::string Name)401 Function *getFunction(std::string Name) {
402 // First, see if the function has already been added to the current module.
403 if (auto *F = TheModule->getFunction(Name))
404 return F;
405
406 // If not, check whether we can codegen the declaration from some existing
407 // prototype.
408 auto FI = FunctionProtos.find(Name);
409 if (FI != FunctionProtos.end())
410 return FI->second->codegen();
411
412 // If no existing prototype exists, return null.
413 return nullptr;
414 }
415
codegen()416 Value *NumberExprAST::codegen() {
417 return ConstantFP::get(getGlobalContext(), APFloat(Val));
418 }
419
codegen()420 Value *VariableExprAST::codegen() {
421 // Look this variable up in the function.
422 Value *V = NamedValues[Name];
423 if (!V)
424 return ErrorV("Unknown variable name");
425 return V;
426 }
427
codegen()428 Value *BinaryExprAST::codegen() {
429 Value *L = LHS->codegen();
430 Value *R = RHS->codegen();
431 if (!L || !R)
432 return nullptr;
433
434 switch (Op) {
435 case '+':
436 return Builder.CreateFAdd(L, R, "addtmp");
437 case '-':
438 return Builder.CreateFSub(L, R, "subtmp");
439 case '*':
440 return Builder.CreateFMul(L, R, "multmp");
441 case '<':
442 L = Builder.CreateFCmpULT(L, R, "cmptmp");
443 // Convert bool 0/1 to double 0.0 or 1.0
444 return Builder.CreateUIToFP(L, Type::getDoubleTy(getGlobalContext()),
445 "booltmp");
446 default:
447 return ErrorV("invalid binary operator");
448 }
449 }
450
codegen()451 Value *CallExprAST::codegen() {
452 // Look up the name in the global module table.
453 Function *CalleeF = getFunction(Callee);
454 if (!CalleeF)
455 return ErrorV("Unknown function referenced");
456
457 // If argument mismatch error.
458 if (CalleeF->arg_size() != Args.size())
459 return ErrorV("Incorrect # arguments passed");
460
461 std::vector<Value *> ArgsV;
462 for (unsigned i = 0, e = Args.size(); i != e; ++i) {
463 ArgsV.push_back(Args[i]->codegen());
464 if (!ArgsV.back())
465 return nullptr;
466 }
467
468 return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
469 }
470
codegen()471 Function *PrototypeAST::codegen() {
472 // Make the function type: double(double,double) etc.
473 std::vector<Type *> Doubles(Args.size(),
474 Type::getDoubleTy(getGlobalContext()));
475 FunctionType *FT =
476 FunctionType::get(Type::getDoubleTy(getGlobalContext()), Doubles, false);
477
478 Function *F =
479 Function::Create(FT, Function::ExternalLinkage, Name, TheModule.get());
480
481 // Set names for all arguments.
482 unsigned Idx = 0;
483 for (auto &Arg : F->args())
484 Arg.setName(Args[Idx++]);
485
486 return F;
487 }
488
codegen()489 Function *FunctionAST::codegen() {
490 // Transfer ownership of the prototype to the FunctionProtos map, but keep a
491 // reference to it for use below.
492 auto &P = *Proto;
493 FunctionProtos[Proto->getName()] = std::move(Proto);
494 Function *TheFunction = getFunction(P.getName());
495 if (!TheFunction)
496 return nullptr;
497
498 // Create a new basic block to start insertion into.
499 BasicBlock *BB = BasicBlock::Create(getGlobalContext(), "entry", TheFunction);
500 Builder.SetInsertPoint(BB);
501
502 // Record the function arguments in the NamedValues map.
503 NamedValues.clear();
504 for (auto &Arg : TheFunction->args())
505 NamedValues[Arg.getName()] = &Arg;
506
507 if (Value *RetVal = Body->codegen()) {
508 // Finish off the function.
509 Builder.CreateRet(RetVal);
510
511 // Validate the generated code, checking for consistency.
512 verifyFunction(*TheFunction);
513
514 // Run the optimizer on the function.
515 TheFPM->run(*TheFunction);
516
517 return TheFunction;
518 }
519
520 // Error reading body, remove function.
521 TheFunction->eraseFromParent();
522 return nullptr;
523 }
524
525 //===----------------------------------------------------------------------===//
526 // Top-Level parsing and JIT Driver
527 //===----------------------------------------------------------------------===//
528
InitializeModuleAndPassManager()529 static void InitializeModuleAndPassManager() {
530 // Open a new module.
531 TheModule = llvm::make_unique<Module>("my cool jit", getGlobalContext());
532 TheModule->setDataLayout(TheJIT->getTargetMachine().createDataLayout());
533
534 // Create a new pass manager attached to it.
535 TheFPM = llvm::make_unique<legacy::FunctionPassManager>(TheModule.get());
536
537 // Do simple "peephole" optimizations and bit-twiddling optzns.
538 TheFPM->add(createInstructionCombiningPass());
539 // Reassociate expressions.
540 TheFPM->add(createReassociatePass());
541 // Eliminate Common SubExpressions.
542 TheFPM->add(createGVNPass());
543 // Simplify the control flow graph (deleting unreachable blocks, etc).
544 TheFPM->add(createCFGSimplificationPass());
545
546 TheFPM->doInitialization();
547 }
548
HandleDefinition()549 static void HandleDefinition() {
550 if (auto FnAST = ParseDefinition()) {
551 if (auto *FnIR = FnAST->codegen()) {
552 fprintf(stderr, "Read function definition:");
553 FnIR->dump();
554 TheJIT->addModule(std::move(TheModule));
555 InitializeModuleAndPassManager();
556 }
557 } else {
558 // Skip token for error recovery.
559 getNextToken();
560 }
561 }
562
HandleExtern()563 static void HandleExtern() {
564 if (auto ProtoAST = ParseExtern()) {
565 if (auto *FnIR = ProtoAST->codegen()) {
566 fprintf(stderr, "Read extern: ");
567 FnIR->dump();
568 FunctionProtos[ProtoAST->getName()] = std::move(ProtoAST);
569 }
570 } else {
571 // Skip token for error recovery.
572 getNextToken();
573 }
574 }
575
HandleTopLevelExpression()576 static void HandleTopLevelExpression() {
577 // Evaluate a top-level expression into an anonymous function.
578 if (auto FnAST = ParseTopLevelExpr()) {
579 if (FnAST->codegen()) {
580
581 // JIT the module containing the anonymous expression, keeping a handle so
582 // we can free it later.
583 auto H = TheJIT->addModule(std::move(TheModule));
584 InitializeModuleAndPassManager();
585
586 // Search the JIT for the __anon_expr symbol.
587 auto ExprSymbol = TheJIT->findSymbol("__anon_expr");
588 assert(ExprSymbol && "Function not found");
589
590 // Get the symbol's address and cast it to the right type (takes no
591 // arguments, returns a double) so we can call it as a native function.
592 double (*FP)() = (double (*)())(intptr_t)ExprSymbol.getAddress();
593 fprintf(stderr, "Evaluated to %f\n", FP());
594
595 // Delete the anonymous expression module from the JIT.
596 TheJIT->removeModule(H);
597 }
598 } else {
599 // Skip token for error recovery.
600 getNextToken();
601 }
602 }
603
604 /// top ::= definition | external | expression | ';'
MainLoop()605 static void MainLoop() {
606 while (1) {
607 fprintf(stderr, "ready> ");
608 switch (CurTok) {
609 case tok_eof:
610 return;
611 case ';': // ignore top-level semicolons.
612 getNextToken();
613 break;
614 case tok_def:
615 HandleDefinition();
616 break;
617 case tok_extern:
618 HandleExtern();
619 break;
620 default:
621 HandleTopLevelExpression();
622 break;
623 }
624 }
625 }
626
627 //===----------------------------------------------------------------------===//
628 // "Library" functions that can be "extern'd" from user code.
629 //===----------------------------------------------------------------------===//
630
631 /// putchard - putchar that takes a double and returns 0.
putchard(double X)632 extern "C" double putchard(double X) {
633 fputc((char)X, stderr);
634 return 0;
635 }
636
637 /// printd - printf that takes a double prints it as "%f\n", returning 0.
printd(double X)638 extern "C" double printd(double X) {
639 fprintf(stderr, "%f\n", X);
640 return 0;
641 }
642
643 //===----------------------------------------------------------------------===//
644 // Main driver code.
645 //===----------------------------------------------------------------------===//
646
main()647 int main() {
648 InitializeNativeTarget();
649 InitializeNativeTargetAsmPrinter();
650 InitializeNativeTargetAsmParser();
651
652 // Install standard binary operators.
653 // 1 is lowest precedence.
654 BinopPrecedence['<'] = 10;
655 BinopPrecedence['+'] = 20;
656 BinopPrecedence['-'] = 20;
657 BinopPrecedence['*'] = 40; // highest.
658
659 // Prime the first token.
660 fprintf(stderr, "ready> ");
661 getNextToken();
662
663 TheJIT = llvm::make_unique<KaleidoscopeJIT>();
664
665 InitializeModuleAndPassManager();
666
667 // Run the main "interpreter loop" now.
668 MainLoop();
669
670 return 0;
671 }
672