1#define MINIMAL_STDERR_OUTPUT
2
3#include "llvm/Analysis/Passes.h"
4#include "llvm/ExecutionEngine/ExecutionEngine.h"
5#include "llvm/ExecutionEngine/MCJIT.h"
6#include "llvm/ExecutionEngine/SectionMemoryManager.h"
7#include "llvm/IR/DataLayout.h"
8#include "llvm/IR/DerivedTypes.h"
9#include "llvm/IR/IRBuilder.h"
10#include "llvm/IR/LLVMContext.h"
11#include "llvm/IR/LegacyPassManager.h"
12#include "llvm/IR/Module.h"
13#include "llvm/IR/Verifier.h"
14#include "llvm/Support/TargetSelect.h"
15#include "llvm/Transforms/Scalar.h"
16#include <cctype>
17#include <cstdio>
18#include <map>
19#include <string>
20#include <vector>
21using namespace llvm;
22
23//===----------------------------------------------------------------------===//
24// Lexer
25//===----------------------------------------------------------------------===//
26
27// The lexer returns tokens [0-255] if it is an unknown character, otherwise one
28// of these for known things.
29enum Token {
30  tok_eof = -1,
31
32  // commands
33  tok_def = -2, tok_extern = -3,
34
35  // primary
36  tok_identifier = -4, tok_number = -5,
37
38  // control
39  tok_if = -6, tok_then = -7, tok_else = -8,
40  tok_for = -9, tok_in = -10,
41
42  // operators
43  tok_binary = -11, tok_unary = -12,
44
45  // var definition
46  tok_var = -13
47};
48
49static std::string IdentifierStr;  // Filled in if tok_identifier
50static double NumVal;              // Filled in if tok_number
51
52/// gettok - Return the next token from standard input.
53static int gettok() {
54  static int LastChar = ' ';
55
56  // Skip any whitespace.
57  while (isspace(LastChar))
58    LastChar = getchar();
59
60  if (isalpha(LastChar)) { // identifier: [a-zA-Z][a-zA-Z0-9]*
61    IdentifierStr = LastChar;
62    while (isalnum((LastChar = getchar())))
63      IdentifierStr += LastChar;
64
65    if (IdentifierStr == "def") return tok_def;
66    if (IdentifierStr == "extern") return tok_extern;
67    if (IdentifierStr == "if") return tok_if;
68    if (IdentifierStr == "then") return tok_then;
69    if (IdentifierStr == "else") return tok_else;
70    if (IdentifierStr == "for") return tok_for;
71    if (IdentifierStr == "in") return tok_in;
72    if (IdentifierStr == "binary") return tok_binary;
73    if (IdentifierStr == "unary") return tok_unary;
74    if (IdentifierStr == "var") return tok_var;
75    return tok_identifier;
76  }
77
78  if (isdigit(LastChar) || LastChar == '.') {   // Number: [0-9.]+
79    std::string NumStr;
80    do {
81      NumStr += LastChar;
82      LastChar = getchar();
83    } while (isdigit(LastChar) || LastChar == '.');
84
85    NumVal = strtod(NumStr.c_str(), 0);
86    return tok_number;
87  }
88
89  if (LastChar == '#') {
90    // Comment until end of line.
91    do LastChar = getchar();
92    while (LastChar != EOF && LastChar != '\n' && LastChar != '\r');
93
94    if (LastChar != EOF)
95      return gettok();
96  }
97
98  // Check for end of file.  Don't eat the EOF.
99  if (LastChar == EOF)
100    return tok_eof;
101
102  // Otherwise, just return the character as its ascii value.
103  int ThisChar = LastChar;
104  LastChar = getchar();
105  return ThisChar;
106}
107
108//===----------------------------------------------------------------------===//
109// Abstract Syntax Tree (aka Parse Tree)
110//===----------------------------------------------------------------------===//
111
112/// ExprAST - Base class for all expression nodes.
113class ExprAST {
114public:
115  virtual ~ExprAST() {}
116  virtual Value *Codegen() = 0;
117};
118
119/// NumberExprAST - Expression class for numeric literals like "1.0".
120class NumberExprAST : public ExprAST {
121  double Val;
122public:
123  NumberExprAST(double val) : Val(val) {}
124  virtual Value *Codegen();
125};
126
127/// VariableExprAST - Expression class for referencing a variable, like "a".
128class VariableExprAST : public ExprAST {
129  std::string Name;
130public:
131  VariableExprAST(const std::string &name) : Name(name) {}
132  const std::string &getName() const { return Name; }
133  virtual Value *Codegen();
134};
135
136/// UnaryExprAST - Expression class for a unary operator.
137class UnaryExprAST : public ExprAST {
138  char Opcode;
139  ExprAST *Operand;
140public:
141  UnaryExprAST(char opcode, ExprAST *operand)
142    : Opcode(opcode), Operand(operand) {}
143  virtual Value *Codegen();
144};
145
146/// BinaryExprAST - Expression class for a binary operator.
147class BinaryExprAST : public ExprAST {
148  char Op;
149  ExprAST *LHS, *RHS;
150public:
151  BinaryExprAST(char op, ExprAST *lhs, ExprAST *rhs)
152    : Op(op), LHS(lhs), RHS(rhs) {}
153  virtual Value *Codegen();
154};
155
156/// CallExprAST - Expression class for function calls.
157class CallExprAST : public ExprAST {
158  std::string Callee;
159  std::vector<ExprAST*> Args;
160public:
161  CallExprAST(const std::string &callee, std::vector<ExprAST*> &args)
162    : Callee(callee), Args(args) {}
163  virtual Value *Codegen();
164};
165
166/// IfExprAST - Expression class for if/then/else.
167class IfExprAST : public ExprAST {
168  ExprAST *Cond, *Then, *Else;
169public:
170  IfExprAST(ExprAST *cond, ExprAST *then, ExprAST *_else)
171  : Cond(cond), Then(then), Else(_else) {}
172  virtual Value *Codegen();
173};
174
175/// ForExprAST - Expression class for for/in.
176class ForExprAST : public ExprAST {
177  std::string VarName;
178  ExprAST *Start, *End, *Step, *Body;
179public:
180  ForExprAST(const std::string &varname, ExprAST *start, ExprAST *end,
181             ExprAST *step, ExprAST *body)
182    : VarName(varname), Start(start), End(end), Step(step), Body(body) {}
183  virtual Value *Codegen();
184};
185
186/// VarExprAST - Expression class for var/in
187class VarExprAST : public ExprAST {
188  std::vector<std::pair<std::string, ExprAST*> > VarNames;
189  ExprAST *Body;
190public:
191  VarExprAST(const std::vector<std::pair<std::string, ExprAST*> > &varnames,
192             ExprAST *body)
193  : VarNames(varnames), Body(body) {}
194
195  virtual Value *Codegen();
196};
197
198/// PrototypeAST - This class represents the "prototype" for a function,
199/// which captures its argument names as well as if it is an operator.
200class PrototypeAST {
201  std::string Name;
202  std::vector<std::string> Args;
203  bool isOperator;
204  unsigned Precedence;  // Precedence if a binary op.
205public:
206  PrototypeAST(const std::string &name, const std::vector<std::string> &args,
207               bool isoperator = false, unsigned prec = 0)
208  : Name(name), Args(args), isOperator(isoperator), Precedence(prec) {}
209
210  bool isUnaryOp() const { return isOperator && Args.size() == 1; }
211  bool isBinaryOp() const { return isOperator && Args.size() == 2; }
212
213  char getOperatorName() const {
214    assert(isUnaryOp() || isBinaryOp());
215    return Name[Name.size()-1];
216  }
217
218  unsigned getBinaryPrecedence() const { return Precedence; }
219
220  Function *Codegen();
221
222  void CreateArgumentAllocas(Function *F);
223};
224
225/// FunctionAST - This class represents a function definition itself.
226class FunctionAST {
227  PrototypeAST *Proto;
228  ExprAST *Body;
229public:
230  FunctionAST(PrototypeAST *proto, ExprAST *body)
231    : Proto(proto), Body(body) {}
232
233  Function *Codegen();
234};
235
236//===----------------------------------------------------------------------===//
237// Parser
238//===----------------------------------------------------------------------===//
239
240/// CurTok/getNextToken - Provide a simple token buffer.  CurTok is the current
241/// token the parser is looking at.  getNextToken reads another token from the
242/// lexer and updates CurTok with its results.
243static int CurTok;
244static int getNextToken() {
245  return CurTok = gettok();
246}
247
248/// BinopPrecedence - This holds the precedence for each binary operator that is
249/// defined.
250static std::map<char, int> BinopPrecedence;
251
252/// GetTokPrecedence - Get the precedence of the pending binary operator token.
253static int GetTokPrecedence() {
254  if (!isascii(CurTok))
255    return -1;
256
257  // Make sure it's a declared binop.
258  int TokPrec = BinopPrecedence[CurTok];
259  if (TokPrec <= 0) return -1;
260  return TokPrec;
261}
262
263/// Error* - These are little helper functions for error handling.
264ExprAST *Error(const char *Str) { fprintf(stderr, "Error: %s\n", Str);return 0;}
265PrototypeAST *ErrorP(const char *Str) { Error(Str); return 0; }
266FunctionAST *ErrorF(const char *Str) { Error(Str); return 0; }
267
268static ExprAST *ParseExpression();
269
270/// identifierexpr
271///   ::= identifier
272///   ::= identifier '(' expression* ')'
273static ExprAST *ParseIdentifierExpr() {
274  std::string IdName = IdentifierStr;
275
276  getNextToken();  // eat identifier.
277
278  if (CurTok != '(') // Simple variable ref.
279    return new VariableExprAST(IdName);
280
281  // Call.
282  getNextToken();  // eat (
283  std::vector<ExprAST*> Args;
284  if (CurTok != ')') {
285    while (1) {
286      ExprAST *Arg = ParseExpression();
287      if (!Arg) return 0;
288      Args.push_back(Arg);
289
290      if (CurTok == ')') break;
291
292      if (CurTok != ',')
293        return Error("Expected ')' or ',' in argument list");
294      getNextToken();
295    }
296  }
297
298  // Eat the ')'.
299  getNextToken();
300
301  return new CallExprAST(IdName, Args);
302}
303
304/// numberexpr ::= number
305static ExprAST *ParseNumberExpr() {
306  ExprAST *Result = new NumberExprAST(NumVal);
307  getNextToken(); // consume the number
308  return Result;
309}
310
311/// parenexpr ::= '(' expression ')'
312static ExprAST *ParseParenExpr() {
313  getNextToken();  // eat (.
314  ExprAST *V = ParseExpression();
315  if (!V) return 0;
316
317  if (CurTok != ')')
318    return Error("expected ')'");
319  getNextToken();  // eat ).
320  return V;
321}
322
323/// ifexpr ::= 'if' expression 'then' expression 'else' expression
324static ExprAST *ParseIfExpr() {
325  getNextToken();  // eat the if.
326
327  // condition.
328  ExprAST *Cond = ParseExpression();
329  if (!Cond) return 0;
330
331  if (CurTok != tok_then)
332    return Error("expected then");
333  getNextToken();  // eat the then
334
335  ExprAST *Then = ParseExpression();
336  if (Then == 0) return 0;
337
338  if (CurTok != tok_else)
339    return Error("expected else");
340
341  getNextToken();
342
343  ExprAST *Else = ParseExpression();
344  if (!Else) return 0;
345
346  return new IfExprAST(Cond, Then, Else);
347}
348
349/// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression
350static ExprAST *ParseForExpr() {
351  getNextToken();  // eat the for.
352
353  if (CurTok != tok_identifier)
354    return Error("expected identifier after for");
355
356  std::string IdName = IdentifierStr;
357  getNextToken();  // eat identifier.
358
359  if (CurTok != '=')
360    return Error("expected '=' after for");
361  getNextToken();  // eat '='.
362
363
364  ExprAST *Start = ParseExpression();
365  if (Start == 0) return 0;
366  if (CurTok != ',')
367    return Error("expected ',' after for start value");
368  getNextToken();
369
370  ExprAST *End = ParseExpression();
371  if (End == 0) return 0;
372
373  // The step value is optional.
374  ExprAST *Step = 0;
375  if (CurTok == ',') {
376    getNextToken();
377    Step = ParseExpression();
378    if (Step == 0) return 0;
379  }
380
381  if (CurTok != tok_in)
382    return Error("expected 'in' after for");
383  getNextToken();  // eat 'in'.
384
385  ExprAST *Body = ParseExpression();
386  if (Body == 0) return 0;
387
388  return new ForExprAST(IdName, Start, End, Step, Body);
389}
390
391/// varexpr ::= 'var' identifier ('=' expression)?
392//                    (',' identifier ('=' expression)?)* 'in' expression
393static ExprAST *ParseVarExpr() {
394  getNextToken();  // eat the var.
395
396  std::vector<std::pair<std::string, ExprAST*> > VarNames;
397
398  // At least one variable name is required.
399  if (CurTok != tok_identifier)
400    return Error("expected identifier after var");
401
402  while (1) {
403    std::string Name = IdentifierStr;
404    getNextToken();  // eat identifier.
405
406    // Read the optional initializer.
407    ExprAST *Init = 0;
408    if (CurTok == '=') {
409      getNextToken(); // eat the '='.
410
411      Init = ParseExpression();
412      if (Init == 0) return 0;
413    }
414
415    VarNames.push_back(std::make_pair(Name, Init));
416
417    // End of var list, exit loop.
418    if (CurTok != ',') break;
419    getNextToken(); // eat the ','.
420
421    if (CurTok != tok_identifier)
422      return Error("expected identifier list after var");
423  }
424
425  // At this point, we have to have 'in'.
426  if (CurTok != tok_in)
427    return Error("expected 'in' keyword after 'var'");
428  getNextToken();  // eat 'in'.
429
430  ExprAST *Body = ParseExpression();
431  if (Body == 0) return 0;
432
433  return new VarExprAST(VarNames, Body);
434}
435
436/// primary
437///   ::= identifierexpr
438///   ::= numberexpr
439///   ::= parenexpr
440///   ::= ifexpr
441///   ::= forexpr
442///   ::= varexpr
443static ExprAST *ParsePrimary() {
444  switch (CurTok) {
445  default: return Error("unknown token when expecting an expression");
446  case tok_identifier: return ParseIdentifierExpr();
447  case tok_number:     return ParseNumberExpr();
448  case '(':            return ParseParenExpr();
449  case tok_if:         return ParseIfExpr();
450  case tok_for:        return ParseForExpr();
451  case tok_var:        return ParseVarExpr();
452  }
453}
454
455/// unary
456///   ::= primary
457///   ::= '!' unary
458static ExprAST *ParseUnary() {
459  // If the current token is not an operator, it must be a primary expr.
460  if (!isascii(CurTok) || CurTok == '(' || CurTok == ',')
461    return ParsePrimary();
462
463  // If this is a unary operator, read it.
464  int Opc = CurTok;
465  getNextToken();
466  if (ExprAST *Operand = ParseUnary())
467    return new UnaryExprAST(Opc, Operand);
468  return 0;
469}
470
471/// binoprhs
472///   ::= ('+' unary)*
473static ExprAST *ParseBinOpRHS(int ExprPrec, ExprAST *LHS) {
474  // If this is a binop, find its precedence.
475  while (1) {
476    int TokPrec = GetTokPrecedence();
477
478    // If this is a binop that binds at least as tightly as the current binop,
479    // consume it, otherwise we are done.
480    if (TokPrec < ExprPrec)
481      return LHS;
482
483    // Okay, we know this is a binop.
484    int BinOp = CurTok;
485    getNextToken();  // eat binop
486
487    // Parse the unary expression after the binary operator.
488    ExprAST *RHS = ParseUnary();
489    if (!RHS) return 0;
490
491    // If BinOp binds less tightly with RHS than the operator after RHS, let
492    // the pending operator take RHS as its LHS.
493    int NextPrec = GetTokPrecedence();
494    if (TokPrec < NextPrec) {
495      RHS = ParseBinOpRHS(TokPrec+1, RHS);
496      if (RHS == 0) return 0;
497    }
498
499    // Merge LHS/RHS.
500    LHS = new BinaryExprAST(BinOp, LHS, RHS);
501  }
502}
503
504/// expression
505///   ::= unary binoprhs
506///
507static ExprAST *ParseExpression() {
508  ExprAST *LHS = ParseUnary();
509  if (!LHS) return 0;
510
511  return ParseBinOpRHS(0, LHS);
512}
513
514/// prototype
515///   ::= id '(' id* ')'
516///   ::= binary LETTER number? (id, id)
517///   ::= unary LETTER (id)
518static PrototypeAST *ParsePrototype() {
519  std::string FnName;
520
521  unsigned Kind = 0; // 0 = identifier, 1 = unary, 2 = binary.
522  unsigned BinaryPrecedence = 30;
523
524  switch (CurTok) {
525  default:
526    return ErrorP("Expected function name in prototype");
527  case tok_identifier:
528    FnName = IdentifierStr;
529    Kind = 0;
530    getNextToken();
531    break;
532  case tok_unary:
533    getNextToken();
534    if (!isascii(CurTok))
535      return ErrorP("Expected unary operator");
536    FnName = "unary";
537    FnName += (char)CurTok;
538    Kind = 1;
539    getNextToken();
540    break;
541  case tok_binary:
542    getNextToken();
543    if (!isascii(CurTok))
544      return ErrorP("Expected binary operator");
545    FnName = "binary";
546    FnName += (char)CurTok;
547    Kind = 2;
548    getNextToken();
549
550    // Read the precedence if present.
551    if (CurTok == tok_number) {
552      if (NumVal < 1 || NumVal > 100)
553        return ErrorP("Invalid precedecnce: must be 1..100");
554      BinaryPrecedence = (unsigned)NumVal;
555      getNextToken();
556    }
557    break;
558  }
559
560  if (CurTok != '(')
561    return ErrorP("Expected '(' in prototype");
562
563  std::vector<std::string> ArgNames;
564  while (getNextToken() == tok_identifier)
565    ArgNames.push_back(IdentifierStr);
566  if (CurTok != ')')
567    return ErrorP("Expected ')' in prototype");
568
569  // success.
570  getNextToken();  // eat ')'.
571
572  // Verify right number of names for operator.
573  if (Kind && ArgNames.size() != Kind)
574    return ErrorP("Invalid number of operands for operator");
575
576  return new PrototypeAST(FnName, ArgNames, Kind != 0, BinaryPrecedence);
577}
578
579/// definition ::= 'def' prototype expression
580static FunctionAST *ParseDefinition() {
581  getNextToken();  // eat def.
582  PrototypeAST *Proto = ParsePrototype();
583  if (Proto == 0) return 0;
584
585  if (ExprAST *E = ParseExpression())
586    return new FunctionAST(Proto, E);
587  return 0;
588}
589
590/// toplevelexpr ::= expression
591static FunctionAST *ParseTopLevelExpr() {
592  if (ExprAST *E = ParseExpression()) {
593    // Make an anonymous proto.
594    PrototypeAST *Proto = new PrototypeAST("", std::vector<std::string>());
595    return new FunctionAST(Proto, E);
596  }
597  return 0;
598}
599
600/// external ::= 'extern' prototype
601static PrototypeAST *ParseExtern() {
602  getNextToken();  // eat extern.
603  return ParsePrototype();
604}
605
606//===----------------------------------------------------------------------===//
607// Quick and dirty hack
608//===----------------------------------------------------------------------===//
609
610// FIXME: Obviously we can do better than this
611std::string GenerateUniqueName(const char *root)
612{
613  static int i = 0;
614  char s[16];
615  sprintf(s, "%s%d", root, i++);
616  std::string S = s;
617  return S;
618}
619
620std::string MakeLegalFunctionName(std::string Name)
621{
622  std::string NewName;
623  if (!Name.length())
624      return GenerateUniqueName("anon_func_");
625
626  // Start with what we have
627  NewName = Name;
628
629  // Look for a numberic first character
630  if (NewName.find_first_of("0123456789") == 0) {
631    NewName.insert(0, 1, 'n');
632  }
633
634  // Replace illegal characters with their ASCII equivalent
635  std::string legal_elements = "_abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
636  size_t pos;
637  while ((pos = NewName.find_first_not_of(legal_elements)) != std::string::npos) {
638    char old_c = NewName.at(pos);
639    char new_str[16];
640    sprintf(new_str, "%d", (int)old_c);
641    NewName = NewName.replace(pos, 1, new_str);
642  }
643
644  return NewName;
645}
646
647//===----------------------------------------------------------------------===//
648// MCJIT helper class
649//===----------------------------------------------------------------------===//
650
651class MCJITHelper
652{
653public:
654  MCJITHelper(LLVMContext& C) : Context(C), OpenModule(NULL) {}
655  ~MCJITHelper();
656
657  Function *getFunction(const std::string FnName);
658  Module *getModuleForNewFunction();
659  void *getPointerToFunction(Function* F);
660  void *getPointerToNamedFunction(const std::string &Name);
661  ExecutionEngine *compileModule(Module *M);
662  void closeCurrentModule();
663  void dump();
664
665private:
666  typedef std::vector<Module*> ModuleVector;
667
668  LLVMContext  &Context;
669  Module       *OpenModule;
670  ModuleVector  Modules;
671  std::map<Module *, ExecutionEngine *> EngineMap;
672};
673
674class HelpingMemoryManager : public SectionMemoryManager
675{
676  HelpingMemoryManager(const HelpingMemoryManager&) = delete;
677  void operator=(const HelpingMemoryManager&) = delete;
678
679public:
680  HelpingMemoryManager(MCJITHelper *Helper) : MasterHelper(Helper) {}
681  virtual ~HelpingMemoryManager() {}
682
683  /// This method returns the address of the specified function.
684  /// Our implementation will attempt to find functions in other
685  /// modules associated with the MCJITHelper to cross link functions
686  /// from one generated module to another.
687  ///
688  /// If \p AbortOnFailure is false and no function with the given name is
689  /// found, this function returns a null pointer. Otherwise, it prints a
690  /// message to stderr and aborts.
691  virtual void *getPointerToNamedFunction(const std::string &Name,
692                                          bool AbortOnFailure = true);
693private:
694  MCJITHelper *MasterHelper;
695};
696
697void *HelpingMemoryManager::getPointerToNamedFunction(const std::string &Name,
698                                        bool AbortOnFailure)
699{
700  // Try the standard symbol resolution first, but ask it not to abort.
701  void *pfn = SectionMemoryManager::getPointerToNamedFunction(Name, false);
702  if (pfn)
703    return pfn;
704
705  pfn = MasterHelper->getPointerToNamedFunction(Name);
706  if (!pfn && AbortOnFailure)
707    report_fatal_error("Program used external function '" + Name +
708                        "' which could not be resolved!");
709  return pfn;
710}
711
712MCJITHelper::~MCJITHelper()
713{
714  // Walk the vector of modules.
715  ModuleVector::iterator it, end;
716  for (it = Modules.begin(), end = Modules.end();
717       it != end; ++it) {
718    // See if we have an execution engine for this module.
719    std::map<Module*, ExecutionEngine*>::iterator mapIt = EngineMap.find(*it);
720    // If we have an EE, the EE owns the module so just delete the EE.
721    if (mapIt != EngineMap.end()) {
722      delete mapIt->second;
723    } else {
724      // Otherwise, we still own the module.  Delete it now.
725      delete *it;
726    }
727  }
728}
729
730Function *MCJITHelper::getFunction(const std::string FnName) {
731  ModuleVector::iterator begin = Modules.begin();
732  ModuleVector::iterator end = Modules.end();
733  ModuleVector::iterator it;
734  for (it = begin; it != end; ++it) {
735    Function *F = (*it)->getFunction(FnName);
736    if (F) {
737      if (*it == OpenModule)
738          return F;
739
740      assert(OpenModule != NULL);
741
742      // This function is in a module that has already been JITed.
743      // We need to generate a new prototype for external linkage.
744      Function *PF = OpenModule->getFunction(FnName);
745      if (PF && !PF->empty()) {
746        ErrorF("redefinition of function across modules");
747        return 0;
748      }
749
750      // If we don't have a prototype yet, create one.
751      if (!PF)
752        PF = Function::Create(F->getFunctionType(),
753                                      Function::ExternalLinkage,
754                                      FnName,
755                                      OpenModule);
756      return PF;
757    }
758  }
759  return NULL;
760}
761
762Module *MCJITHelper::getModuleForNewFunction() {
763  // If we have a Module that hasn't been JITed, use that.
764  if (OpenModule)
765    return OpenModule;
766
767  // Otherwise create a new Module.
768  std::string ModName = GenerateUniqueName("mcjit_module_");
769  Module *M = new Module(ModName, Context);
770  Modules.push_back(M);
771  OpenModule = M;
772  return M;
773}
774
775void *MCJITHelper::getPointerToFunction(Function* F) {
776  // Look for this function in an existing module
777  ModuleVector::iterator begin = Modules.begin();
778  ModuleVector::iterator end = Modules.end();
779  ModuleVector::iterator it;
780  std::string FnName = F->getName();
781  for (it = begin; it != end; ++it) {
782    Function *MF = (*it)->getFunction(FnName);
783    if (MF == F) {
784      std::map<Module*, ExecutionEngine*>::iterator eeIt = EngineMap.find(*it);
785      if (eeIt != EngineMap.end()) {
786        void *P = eeIt->second->getPointerToFunction(F);
787        if (P)
788          return P;
789      } else {
790        ExecutionEngine *EE = compileModule(*it);
791        void *P = EE->getPointerToFunction(F);
792        if (P)
793          return P;
794      }
795    }
796  }
797  return NULL;
798}
799
800void MCJITHelper::closeCurrentModule() {
801  OpenModule = NULL;
802}
803
804ExecutionEngine *MCJITHelper::compileModule(Module *M) {
805  if (M == OpenModule)
806    closeCurrentModule();
807
808  std::string ErrStr;
809  ExecutionEngine *NewEngine = EngineBuilder(M)
810                                            .setErrorStr(&ErrStr)
811                                            .setMCJITMemoryManager(new HelpingMemoryManager(this))
812                                            .create();
813  if (!NewEngine) {
814    fprintf(stderr, "Could not create ExecutionEngine: %s\n", ErrStr.c_str());
815    exit(1);
816  }
817
818  // Create a function pass manager for this engine
819  FunctionPassManager *FPM = new FunctionPassManager(M);
820
821  // Set up the optimizer pipeline.  Start with registering info about how the
822  // target lays out data structures.
823  FPM->add(new DataLayout(*NewEngine->getDataLayout()));
824  // Provide basic AliasAnalysis support for GVN.
825  FPM->add(createBasicAliasAnalysisPass());
826  // Promote allocas to registers.
827  FPM->add(createPromoteMemoryToRegisterPass());
828  // Do simple "peephole" optimizations and bit-twiddling optzns.
829  FPM->add(createInstructionCombiningPass());
830  // Reassociate expressions.
831  FPM->add(createReassociatePass());
832  // Eliminate Common SubExpressions.
833  FPM->add(createGVNPass());
834  // Simplify the control flow graph (deleting unreachable blocks, etc).
835  FPM->add(createCFGSimplificationPass());
836  FPM->doInitialization();
837
838  // For each function in the module
839  Module::iterator it;
840  Module::iterator end = M->end();
841  for (it = M->begin(); it != end; ++it) {
842    // Run the FPM on this function
843    FPM->run(*it);
844  }
845
846  // We don't need this anymore
847  delete FPM;
848
849  // Store this engine
850  EngineMap[M] = NewEngine;
851  NewEngine->finalizeObject();
852
853  return NewEngine;
854}
855
856void *MCJITHelper::getPointerToNamedFunction(const std::string &Name)
857{
858  // Look for the functions in our modules, compiling only as necessary
859  ModuleVector::iterator begin = Modules.begin();
860  ModuleVector::iterator end = Modules.end();
861  ModuleVector::iterator it;
862  for (it = begin; it != end; ++it) {
863    Function *F = (*it)->getFunction(Name);
864    if (F && !F->empty()) {
865      std::map<Module*, ExecutionEngine*>::iterator eeIt = EngineMap.find(*it);
866      if (eeIt != EngineMap.end()) {
867        void *P = eeIt->second->getPointerToFunction(F);
868        if (P)
869          return P;
870      } else {
871        ExecutionEngine *EE = compileModule(*it);
872        void *P = EE->getPointerToFunction(F);
873        if (P)
874          return P;
875      }
876    }
877  }
878  return NULL;
879}
880
881void MCJITHelper::dump()
882{
883  ModuleVector::iterator begin = Modules.begin();
884  ModuleVector::iterator end = Modules.end();
885  ModuleVector::iterator it;
886  for (it = begin; it != end; ++it)
887    (*it)->dump();
888}
889
890//===----------------------------------------------------------------------===//
891// Code Generation
892//===----------------------------------------------------------------------===//
893
894static MCJITHelper *TheHelper;
895static IRBuilder<> Builder(getGlobalContext());
896static std::map<std::string, AllocaInst*> NamedValues;
897
898Value *ErrorV(const char *Str) { Error(Str); return 0; }
899
900/// CreateEntryBlockAlloca - Create an alloca instruction in the entry block of
901/// the function.  This is used for mutable variables etc.
902static AllocaInst *CreateEntryBlockAlloca(Function *TheFunction,
903                                          const std::string &VarName) {
904  IRBuilder<> TmpB(&TheFunction->getEntryBlock(),
905                 TheFunction->getEntryBlock().begin());
906  return TmpB.CreateAlloca(Type::getDoubleTy(getGlobalContext()), 0,
907                           VarName.c_str());
908}
909
910Value *NumberExprAST::Codegen() {
911  return ConstantFP::get(getGlobalContext(), APFloat(Val));
912}
913
914Value *VariableExprAST::Codegen() {
915  // Look this variable up in the function.
916  Value *V = NamedValues[Name];
917  char ErrStr[256];
918  sprintf(ErrStr, "Unknown variable name %s", Name.c_str());
919  if (V == 0) return ErrorV(ErrStr);
920
921  // Load the value.
922  return Builder.CreateLoad(V, Name.c_str());
923}
924
925Value *UnaryExprAST::Codegen() {
926  Value *OperandV = Operand->Codegen();
927  if (OperandV == 0) return 0;
928
929  Function *F = TheHelper->getFunction(MakeLegalFunctionName(std::string("unary")+Opcode));
930  if (F == 0)
931    return ErrorV("Unknown unary operator");
932
933  return Builder.CreateCall(F, OperandV, "unop");
934}
935
936Value *BinaryExprAST::Codegen() {
937  // Special case '=' because we don't want to emit the LHS as an expression.
938  if (Op == '=') {
939    // Assignment requires the LHS to be an identifier.
940    VariableExprAST *LHSE = static_cast<VariableExprAST*>(LHS);
941    if (!LHSE)
942      return ErrorV("destination of '=' must be a variable");
943    // Codegen the RHS.
944    Value *Val = RHS->Codegen();
945    if (Val == 0) return 0;
946
947    // Look up the name.
948    Value *Variable = NamedValues[LHSE->getName()];
949    if (Variable == 0) return ErrorV("Unknown variable name");
950
951    Builder.CreateStore(Val, Variable);
952    return Val;
953  }
954
955  Value *L = LHS->Codegen();
956  Value *R = RHS->Codegen();
957  if (L == 0 || R == 0) return 0;
958
959  switch (Op) {
960  case '+': return Builder.CreateFAdd(L, R, "addtmp");
961  case '-': return Builder.CreateFSub(L, R, "subtmp");
962  case '*': return Builder.CreateFMul(L, R, "multmp");
963  case '/': return Builder.CreateFDiv(L, R, "divtmp");
964  case '<':
965    L = Builder.CreateFCmpULT(L, R, "cmptmp");
966    // Convert bool 0/1 to double 0.0 or 1.0
967    return Builder.CreateUIToFP(L, Type::getDoubleTy(getGlobalContext()),
968                                "booltmp");
969  default: break;
970  }
971
972  // If it wasn't a builtin binary operator, it must be a user defined one. Emit
973  // a call to it.
974  Function *F = TheHelper->getFunction(MakeLegalFunctionName(std::string("binary")+Op));
975  assert(F && "binary operator not found!");
976
977  Value *Ops[] = { L, R };
978  return Builder.CreateCall(F, Ops, "binop");
979}
980
981Value *CallExprAST::Codegen() {
982  // Look up the name in the global module table.
983  Function *CalleeF = TheHelper->getFunction(Callee);
984  if (CalleeF == 0)
985    return ErrorV("Unknown function referenced");
986
987  // If argument mismatch error.
988  if (CalleeF->arg_size() != Args.size())
989    return ErrorV("Incorrect # arguments passed");
990
991  std::vector<Value*> ArgsV;
992  for (unsigned i = 0, e = Args.size(); i != e; ++i) {
993    ArgsV.push_back(Args[i]->Codegen());
994    if (ArgsV.back() == 0) return 0;
995  }
996
997  return Builder.CreateCall(CalleeF, ArgsV, "calltmp");
998}
999
1000Value *IfExprAST::Codegen() {
1001  Value *CondV = Cond->Codegen();
1002  if (CondV == 0) return 0;
1003
1004  // Convert condition to a bool by comparing equal to 0.0.
1005  CondV = Builder.CreateFCmpONE(CondV,
1006                              ConstantFP::get(getGlobalContext(), APFloat(0.0)),
1007                                "ifcond");
1008
1009  Function *TheFunction = Builder.GetInsertBlock()->getParent();
1010
1011  // Create blocks for the then and else cases.  Insert the 'then' block at the
1012  // end of the function.
1013  BasicBlock *ThenBB = BasicBlock::Create(getGlobalContext(), "then", TheFunction);
1014  BasicBlock *ElseBB = BasicBlock::Create(getGlobalContext(), "else");
1015  BasicBlock *MergeBB = BasicBlock::Create(getGlobalContext(), "ifcont");
1016
1017  Builder.CreateCondBr(CondV, ThenBB, ElseBB);
1018
1019  // Emit then value.
1020  Builder.SetInsertPoint(ThenBB);
1021
1022  Value *ThenV = Then->Codegen();
1023  if (ThenV == 0) return 0;
1024
1025  Builder.CreateBr(MergeBB);
1026  // Codegen of 'Then' can change the current block, update ThenBB for the PHI.
1027  ThenBB = Builder.GetInsertBlock();
1028
1029  // Emit else block.
1030  TheFunction->getBasicBlockList().push_back(ElseBB);
1031  Builder.SetInsertPoint(ElseBB);
1032
1033  Value *ElseV = Else->Codegen();
1034  if (ElseV == 0) return 0;
1035
1036  Builder.CreateBr(MergeBB);
1037  // Codegen of 'Else' can change the current block, update ElseBB for the PHI.
1038  ElseBB = Builder.GetInsertBlock();
1039
1040  // Emit merge block.
1041  TheFunction->getBasicBlockList().push_back(MergeBB);
1042  Builder.SetInsertPoint(MergeBB);
1043  PHINode *PN = Builder.CreatePHI(Type::getDoubleTy(getGlobalContext()), 2,
1044                                  "iftmp");
1045
1046  PN->addIncoming(ThenV, ThenBB);
1047  PN->addIncoming(ElseV, ElseBB);
1048  return PN;
1049}
1050
1051Value *ForExprAST::Codegen() {
1052  // Output this as:
1053  //   var = alloca double
1054  //   ...
1055  //   start = startexpr
1056  //   store start -> var
1057  //   goto loop
1058  // loop:
1059  //   ...
1060  //   bodyexpr
1061  //   ...
1062  // loopend:
1063  //   step = stepexpr
1064  //   endcond = endexpr
1065  //
1066  //   curvar = load var
1067  //   nextvar = curvar + step
1068  //   store nextvar -> var
1069  //   br endcond, loop, endloop
1070  // outloop:
1071
1072  Function *TheFunction = Builder.GetInsertBlock()->getParent();
1073
1074  // Create an alloca for the variable in the entry block.
1075  AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
1076
1077  // Emit the start code first, without 'variable' in scope.
1078  Value *StartVal = Start->Codegen();
1079  if (StartVal == 0) return 0;
1080
1081  // Store the value into the alloca.
1082  Builder.CreateStore(StartVal, Alloca);
1083
1084  // Make the new basic block for the loop header, inserting after current
1085  // block.
1086  BasicBlock *LoopBB = BasicBlock::Create(getGlobalContext(), "loop", TheFunction);
1087
1088  // Insert an explicit fall through from the current block to the LoopBB.
1089  Builder.CreateBr(LoopBB);
1090
1091  // Start insertion in LoopBB.
1092  Builder.SetInsertPoint(LoopBB);
1093
1094  // Within the loop, the variable is defined equal to the PHI node.  If it
1095  // shadows an existing variable, we have to restore it, so save it now.
1096  AllocaInst *OldVal = NamedValues[VarName];
1097  NamedValues[VarName] = Alloca;
1098
1099  // Emit the body of the loop.  This, like any other expr, can change the
1100  // current BB.  Note that we ignore the value computed by the body, but don't
1101  // allow an error.
1102  if (Body->Codegen() == 0)
1103    return 0;
1104
1105  // Emit the step value.
1106  Value *StepVal;
1107  if (Step) {
1108    StepVal = Step->Codegen();
1109    if (StepVal == 0) return 0;
1110  } else {
1111    // If not specified, use 1.0.
1112    StepVal = ConstantFP::get(getGlobalContext(), APFloat(1.0));
1113  }
1114
1115  // Compute the end condition.
1116  Value *EndCond = End->Codegen();
1117  if (EndCond == 0) return EndCond;
1118
1119  // Reload, increment, and restore the alloca.  This handles the case where
1120  // the body of the loop mutates the variable.
1121  Value *CurVar = Builder.CreateLoad(Alloca, VarName.c_str());
1122  Value *NextVar = Builder.CreateFAdd(CurVar, StepVal, "nextvar");
1123  Builder.CreateStore(NextVar, Alloca);
1124
1125  // Convert condition to a bool by comparing equal to 0.0.
1126  EndCond = Builder.CreateFCmpONE(EndCond,
1127                              ConstantFP::get(getGlobalContext(), APFloat(0.0)),
1128                                  "loopcond");
1129
1130  // Create the "after loop" block and insert it.
1131  BasicBlock *AfterBB = BasicBlock::Create(getGlobalContext(), "afterloop", TheFunction);
1132
1133  // Insert the conditional branch into the end of LoopEndBB.
1134  Builder.CreateCondBr(EndCond, LoopBB, AfterBB);
1135
1136  // Any new code will be inserted in AfterBB.
1137  Builder.SetInsertPoint(AfterBB);
1138
1139  // Restore the unshadowed variable.
1140  if (OldVal)
1141    NamedValues[VarName] = OldVal;
1142  else
1143    NamedValues.erase(VarName);
1144
1145
1146  // for expr always returns 0.0.
1147  return Constant::getNullValue(Type::getDoubleTy(getGlobalContext()));
1148}
1149
1150Value *VarExprAST::Codegen() {
1151  std::vector<AllocaInst *> OldBindings;
1152
1153  Function *TheFunction = Builder.GetInsertBlock()->getParent();
1154
1155  // Register all variables and emit their initializer.
1156  for (unsigned i = 0, e = VarNames.size(); i != e; ++i) {
1157    const std::string &VarName = VarNames[i].first;
1158    ExprAST *Init = VarNames[i].second;
1159
1160    // Emit the initializer before adding the variable to scope, this prevents
1161    // the initializer from referencing the variable itself, and permits stuff
1162    // like this:
1163    //  var a = 1 in
1164    //    var a = a in ...   # refers to outer 'a'.
1165    Value *InitVal;
1166    if (Init) {
1167      InitVal = Init->Codegen();
1168      if (InitVal == 0) return 0;
1169    } else { // If not specified, use 0.0.
1170      InitVal = ConstantFP::get(getGlobalContext(), APFloat(0.0));
1171    }
1172
1173    AllocaInst *Alloca = CreateEntryBlockAlloca(TheFunction, VarName);
1174    Builder.CreateStore(InitVal, Alloca);
1175
1176    // Remember the old variable binding so that we can restore the binding when
1177    // we unrecurse.
1178    OldBindings.push_back(NamedValues[VarName]);
1179
1180    // Remember this binding.
1181    NamedValues[VarName] = Alloca;
1182  }
1183
1184  // Codegen the body, now that all vars are in scope.
1185  Value *BodyVal = Body->Codegen();
1186  if (BodyVal == 0) return 0;
1187
1188  // Pop all our variables from scope.
1189  for (unsigned i = 0, e = VarNames.size(); i != e; ++i)
1190    NamedValues[VarNames[i].first] = OldBindings[i];
1191
1192  // Return the body computation.
1193  return BodyVal;
1194}
1195
1196Function *PrototypeAST::Codegen() {
1197  // Make the function type:  double(double,double) etc.
1198  std::vector<Type*> Doubles(Args.size(),
1199                             Type::getDoubleTy(getGlobalContext()));
1200  FunctionType *FT = FunctionType::get(Type::getDoubleTy(getGlobalContext()),
1201                                       Doubles, false);
1202
1203  std::string FnName = MakeLegalFunctionName(Name);
1204
1205  Module* M = TheHelper->getModuleForNewFunction();
1206
1207  Function *F = Function::Create(FT, Function::ExternalLinkage, FnName, M);
1208
1209  // If F conflicted, there was already something named 'FnName'.  If it has a
1210  // body, don't allow redefinition or reextern.
1211  if (F->getName() != FnName) {
1212    // Delete the one we just made and get the existing one.
1213    F->eraseFromParent();
1214    F = M->getFunction(Name);
1215
1216    // If F already has a body, reject this.
1217    if (!F->empty()) {
1218      ErrorF("redefinition of function");
1219      return 0;
1220    }
1221
1222    // If F took a different number of args, reject.
1223    if (F->arg_size() != Args.size()) {
1224      ErrorF("redefinition of function with different # args");
1225      return 0;
1226    }
1227  }
1228
1229  // Set names for all arguments.
1230  unsigned Idx = 0;
1231  for (Function::arg_iterator AI = F->arg_begin(); Idx != Args.size();
1232       ++AI, ++Idx)
1233    AI->setName(Args[Idx]);
1234
1235  return F;
1236}
1237
1238/// CreateArgumentAllocas - Create an alloca for each argument and register the
1239/// argument in the symbol table so that references to it will succeed.
1240void PrototypeAST::CreateArgumentAllocas(Function *F) {
1241  Function::arg_iterator AI = F->arg_begin();
1242  for (unsigned Idx = 0, e = Args.size(); Idx != e; ++Idx, ++AI) {
1243    // Create an alloca for this variable.
1244    AllocaInst *Alloca = CreateEntryBlockAlloca(F, Args[Idx]);
1245
1246    // Store the initial value into the alloca.
1247    Builder.CreateStore(AI, Alloca);
1248
1249    // Add arguments to variable symbol table.
1250    NamedValues[Args[Idx]] = Alloca;
1251  }
1252}
1253
1254Function *FunctionAST::Codegen() {
1255  NamedValues.clear();
1256
1257  Function *TheFunction = Proto->Codegen();
1258  if (TheFunction == 0)
1259    return 0;
1260
1261  // If this is an operator, install it.
1262  if (Proto->isBinaryOp())
1263    BinopPrecedence[Proto->getOperatorName()] = Proto->getBinaryPrecedence();
1264
1265  // Create a new basic block to start insertion into.
1266  BasicBlock *BB = BasicBlock::Create(getGlobalContext(), "entry", TheFunction);
1267  Builder.SetInsertPoint(BB);
1268
1269  // Add all arguments to the symbol table and create their allocas.
1270  Proto->CreateArgumentAllocas(TheFunction);
1271
1272  if (Value *RetVal = Body->Codegen()) {
1273    // Finish off the function.
1274    Builder.CreateRet(RetVal);
1275
1276    // Validate the generated code, checking for consistency.
1277    verifyFunction(*TheFunction);
1278
1279    return TheFunction;
1280  }
1281
1282  // Error reading body, remove function.
1283  TheFunction->eraseFromParent();
1284
1285  if (Proto->isBinaryOp())
1286    BinopPrecedence.erase(Proto->getOperatorName());
1287  return 0;
1288}
1289
1290//===----------------------------------------------------------------------===//
1291// Top-Level parsing and JIT Driver
1292//===----------------------------------------------------------------------===//
1293
1294static void HandleDefinition() {
1295  if (FunctionAST *F = ParseDefinition()) {
1296    TheHelper->closeCurrentModule();
1297    if (Function *LF = F->Codegen()) {
1298#ifndef MINIMAL_STDERR_OUTPUT
1299      fprintf(stderr, "Read function definition:");
1300      LF->dump();
1301#endif
1302    }
1303  } else {
1304    // Skip token for error recovery.
1305    getNextToken();
1306  }
1307}
1308
1309static void HandleExtern() {
1310  if (PrototypeAST *P = ParseExtern()) {
1311    if (Function *F = P->Codegen()) {
1312#ifndef MINIMAL_STDERR_OUTPUT
1313      fprintf(stderr, "Read extern: ");
1314      F->dump();
1315#endif
1316    }
1317  } else {
1318    // Skip token for error recovery.
1319    getNextToken();
1320  }
1321}
1322
1323static void HandleTopLevelExpression() {
1324  // Evaluate a top-level expression into an anonymous function.
1325  if (FunctionAST *F = ParseTopLevelExpr()) {
1326    if (Function *LF = F->Codegen()) {
1327      // JIT the function, returning a function pointer.
1328      void *FPtr = TheHelper->getPointerToFunction(LF);
1329
1330      // Cast it to the right type (takes no arguments, returns a double) so we
1331      // can call it as a native function.
1332      double (*FP)() = (double (*)())(intptr_t)FPtr;
1333#ifdef MINIMAL_STDERR_OUTPUT
1334      FP();
1335#else
1336      fprintf(stderr, "Evaluated to %f\n", FP());
1337#endif
1338    }
1339  } else {
1340    // Skip token for error recovery.
1341    getNextToken();
1342  }
1343}
1344
1345/// top ::= definition | external | expression | ';'
1346static void MainLoop() {
1347  while (1) {
1348#ifndef MINIMAL_STDERR_OUTPUT
1349    fprintf(stderr, "ready> ");
1350#endif
1351    switch (CurTok) {
1352    case tok_eof:    return;
1353    case ';':        getNextToken(); break;  // ignore top-level semicolons.
1354    case tok_def:    HandleDefinition(); break;
1355    case tok_extern: HandleExtern(); break;
1356    default:         HandleTopLevelExpression(); break;
1357    }
1358  }
1359}
1360
1361//===----------------------------------------------------------------------===//
1362// "Library" functions that can be "extern'd" from user code.
1363//===----------------------------------------------------------------------===//
1364
1365/// putchard - putchar that takes a double and returns 0.
1366extern "C"
1367double putchard(double X) {
1368  putchar((char)X);
1369  return 0;
1370}
1371
1372/// printd - printf that takes a double prints it as "%f\n", returning 0.
1373extern "C"
1374double printd(double X) {
1375  printf("%f", X);
1376  return 0;
1377}
1378
1379extern "C"
1380double printlf() {
1381  printf("\n");
1382  return 0;
1383}
1384
1385//===----------------------------------------------------------------------===//
1386// Main driver code.
1387//===----------------------------------------------------------------------===//
1388
1389int main() {
1390  InitializeNativeTarget();
1391  InitializeNativeTargetAsmPrinter();
1392  InitializeNativeTargetAsmParser();
1393  LLVMContext &Context = getGlobalContext();
1394
1395  // Install standard binary operators.
1396  // 1 is lowest precedence.
1397  BinopPrecedence['='] = 2;
1398  BinopPrecedence['<'] = 10;
1399  BinopPrecedence['+'] = 20;
1400  BinopPrecedence['-'] = 20;
1401  BinopPrecedence['/'] = 40;
1402  BinopPrecedence['*'] = 40;  // highest.
1403
1404  // Prime the first token.
1405#ifndef MINIMAL_STDERR_OUTPUT
1406  fprintf(stderr, "ready> ");
1407#endif
1408  getNextToken();
1409
1410  // Make the helper, which holds all the code.
1411  TheHelper = new MCJITHelper(Context);
1412
1413  // Run the main "interpreter loop" now.
1414  MainLoop();
1415
1416#ifndef MINIMAL_STDERR_OUTPUT
1417  // Print out all of the generated code.
1418  TheHelper->dump();
1419#endif
1420
1421  return 0;
1422}
1423